Bell-type continuously transmission and straddle-type vehicle including the same

ES 2 392 589 T3

DESCRIPTION

Straddle-type vehicle and belt drive including belt drive

BACKGROUND

The present invention relates to a belt type continuously variable transmission and a straddle type vehicle including the belt type continuously variable transmission.

At present, a straddle-type vehicle is known which includes a belt-type continuously variable transmission. This belt-type continuously variable transmission has a primary pulley that receives the driving force from a motor, and a secondary pulley that receives the driving force from the primary pulley through a belt. At least either the primary pulley or the secondary pulley has a variable belt winding diameter, and the speed change ratio is controlled by varying the ratio of the belt winding diameter of the primary pulley to the belt winding diameter of the secondary pulley.

More specifically, the primary pulley typically includes a fixed pulley element (hereinafter referred to as "primary fixed pulley element"), and a movable pulley element (hereinafter referred to as "primary movable pulley element. ”) Arranged opposite the primary fixed pulley element. The primary fixed pulley member and the primary movable pulley member form a substantially V-shaped belt groove in cross-sectional view into which a belt is wound. The primary movable pulley element can be moved in the direction of the axis of rotation to change its position from the primary fixed pulley element. (That is, the primary movable pulley member can move toward or away from the primary stationary pulley member.)

The primary pulley has a cam plate arranged opposite the side of the primary movable pulley element opposite the side facing the primary fixed pulley element. The cam plate is constructed so that it does not change its position in the axial direction from the primary stationary pulley member. The primary movable pulley member has a plurality of guide ribs that extend toward the cam plate. The cam plate has guide grooves with which the guide ribs engage to slide in the guide grooves. This engagement between the guide ribs and the guide grooves prevents rotation of the primary movable pulley member relative to the cam plate, and enables the primary movable pulley member to be slidably guided in the axial direction.

Between the primary pulley element and the cam plate a plurality of roller weights are provided which can move in the radial direction of the primary pulley and can circulate with the rotations of the primary movable pulley element and the cam plate. The primary movable pulley member has a plurality of stops that extend toward the outer circumference of the cam plate. These stops determine the maximum offset positions of the roll weights outward in the radial direction.

Similar to the primary pulley, the secondary pulley includes a fixed pulley element (hereinafter referred to as "secondary fixed pulley element"), and a movable pulley element (hereinafter referred to as "secondary fixed pulley element. of secondary mobile pulley ”) arranged opposite to the secondary fixed pulley element. The secondary fixed pulley member and the secondary movable pulley member form a substantially V-shaped belt groove in the cross-sectional view into which the belt is wound. The secondary movable pulley member is spring biased in the direction in which the width of the belt groove narrows (that is, the direction in which the distance from the secondary fixed pulley member is reduced).

When the rotation speed of the primary pulley is low, the width of the belt groove of the secondary pulley is kept small by the biasing force of the spring. Therefore, the belt winding diameter of the secondary pulley becomes relatively large. In this state, the belt is pulled towards the secondary pulley. By this pulling force, the roller weights are kept close to the axis of rotation, and the width of the belt groove of the primary pulley is kept relatively large. As a result, the rate of change of speed increases.

As the rotational speed of the primary pulley increases, the centrifugal force acting on the roller weights increases correspondingly. Thus, the roller weights are shifted outward in the radial direction while pressing the primary movable pulley member towards the primary stationary pulley member. As a result, the belt winding diameter of the primary pulley increases. With increasing this diameter, the belt is pulled towards the primary pulley, and the belt winding diameter of the secondary pulley is reduced. Therefore, the speed of rotation of the primary pulley, that is, the revolution of the motor, increases and the rate of change of speed is reduced. The rate of change of speed becomes minimum when the roller weights reach the maximum travel positions where the roller weights contact the stops, a state in which the width of the belt groove of the primary pulley becomes minimal.

A structure of a primary pulley in the related art will now be described in more detail with reference to Figures 14 and 15.

ES 2 392 589 T3

Figure 14 is a cross-sectional view of a related art primary pulley 136 disclosed in Japanese Patent No. 3,008,214. Figure 15 is a plan view of primary pulley 136 viewed from cam plate 160. The primary pulley 136 has a fixed pulley element 136a, a movable pulley element 136b, the cam plate 160 (ramp plate), and a roller weight 144 (centrifugal force) provided between the movable pulley element 136b and the cam plate 160.

A plurality of guide ribs 155 extending in the radial direction are provided on the radially outer surface of the movable pulley element 136b on the cam plate 160 side at equal intervals in the circumferential direction of the primary pulley 136. . Sliders 162 each with a slide groove 163 (guide groove) with which the corresponding guide rib 155 slidably engages are mounted on the cam plate 160. By engagement between the slide grooves 163 of the sliders 162 and the guide ribs 155, rotation of the cam plate 160 relative to the movable pulley member 136b is prevented. When the cam plate 160 is moved in the axial direction to change its position relative to the movable pulley member 136b, the cam plate 160 is guided in the axial direction of the primary pulley 136 by sliding the guide ribs 155 in the sliding grooves 163.

According to the technique in the related art illustrated in Figures 14 and 15, each joint portion 160a of the sliders 162 that is provided in the tapered cam plate 160 is formed by deep drawing to expand towards the movable pulley element 136b. so that the direction of the slider 162 (opening direction of the sliding slot 163) crosses the sliding direction of the slider 162 (i.e. the axial direction of the primary pulley 136) at right angles (see JP-A-2002-301525 (particularly Figure 1) and Japanese Patent No. 3,238,303 (particularly Figure 2) as well).

However, the deep drawing process in the cam plate 160 is extremely difficult. Therefore, the manufacture of the belt-type continuously variable transmission becomes difficult.

The invention seeks to provide a belt-type continuously variable transmission that can be easily manufactured.

SUMMARY

Aspects of the invention are defined in the claims.

A belt-type continuously variable transmission according to one aspect of the invention includes a primary pulley, a secondary pulley, and a belt. The belt is wrapped around the primary pulley and the secondary pulley. The primary pulley rolls around an axis of rotation.

In one embodiment of the invention the primary pulley includes a first pulley element, a second pulley element, a cam plate, and a pressure element. The primary pulley can move in the direction of extension of the axis of rotation. The second pulley element is arranged in a position offset from the first pulley element towards one side of the direction of extension of the axis of rotation. The second pulley element is opposite the first pulley element. The first pulley element and the second pulley element form a belt groove around which the belt is wound. The cam plate is arranged in a position offset from the first pulley member to the other side of the direction of extension of the axis of rotation. The cam plate is opposite the first pulley element. The cam plate and the first pulley element produce a space that tapers towards the radially outer portion of the first pulley element. The pressure element is arranged in the space between the first pulley element and the cam plate. The pressure element rotates around the axis of rotation according to the rotation of the first pulley element. The pressure element narrows the width of the belt groove by moving towards the radially outer part of the first pulley element while pressing the first pulley element against the second pulley element by the centrifugal force generated during the turns.

The first pulley element has a guide element. The guide element extends towards the cam plate. The cam plate has a sliding element. The slide member has a guide groove that engages with the guide member so that the slide member can slide relative to the guide member. In an embodiment of a belt-type continuously variable transmission according to the invention, the position of the radially outer part of the end surface of the slide member on the other side of the direction of extension of the axis of rotation is shifted to one side of the direction of extension of the axis of rotation from the position of the part radially interior of the end surface of the slide member on the other side of the direction of extension of the axis of rotation.

A straddle-type vehicle according to one aspect of the invention includes such a belt-type continuously variable transmission.

The description "the part of the plate main body opposite the guide element is notched" herein includes not only the state in which a part of the plate main body is practically notched but also the state in which the part of the plate main body opposite the guide element has a notched shape produced for various reasons. Therefore, the stages of formation and the method of formation of the

ES 2 392 589 T3 notch are not specifically limited. For example, the plate main body having a shape including a notched portion opposite the guide member can be formed by a single pressing step.

A continuously variable belt-type transmission provided according to the invention can be easily manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are described hereinafter, by way of example only, with reference to the accompanying drawings.

Figure 1 is a side view of a motorcycle according to the invention.

Figure 2 is a cross-sectional view of a structure of a motor unit.

Figure 3 is a plan view of a primary movable pulley member to which a cam plate is attached viewed from the center in the width direction of the vehicle.

Figure 4 is a plan view of the primary pulley member viewed from the center in the width direction of the vehicle.

Figure 5 is a plan view of a plate main body seen from the primary movable pulley element.

Figure 6 is a perspective view of the plate main body.

Figure 7 is a plan view of the main plate body.

Figure 8 is a view, seen from a line VIII-VIII in Figure 7.

Figure 9 is a perspective view of a slider.

Figure 10 is a side view of the slider.

Figure 11 is a front view of the slider.

Figure 12 schematically illustrates the state of engagement between the cam plate and a guide rib. More specifically, Figure 12 (a) schematically illustrates an engagement between the cam plate and the guide rib according to the invention when the width of a guide groove is maximum. Fig. 12 (b) schematically illustrates an engagement between the cam plate and the guide rib in the related art when the width of the guide groove is maximum. Figure 12 (c) schematically illustrates an engagement between the cam plate and the guide rib according to the invention when the width of the guide groove is minimal. Figure 12 (d) schematically illustrates an engagement between the cam plate and the guide rib in the related art when the width of the guide groove is minimal.

Figure 13 is a side view of a slider in a modified example.

Figure 14 is a cross-sectional view of a primary pulley in the related art shown in Japanese Patent No. 008,214.

Figure 15 is a plan view of the primary pulley in the related art shown in Japanese Patent No. 008,214 viewed from a cam plate.

DETAILED DESCRIPTION

According to the related art structure, the cam plate slider attachment parts 160a are formed by deep drawing so that the slider extension direction crosses the axial direction (travel direction) at right angles as illustrated. in Figure 14 (see Figures 12 (b) and 12 (d) as well), expecting smooth movement of cam plate 160 in this structure. The present inventors found that the arrangement of the slider extension direction arranged orthogonal to the axial direction is largely unrelated to the smooth movement of the slider, and therefore they practiced this embodiment based on their findings.

A specific structure according to an embodiment of the invention is described in detail with reference to the drawings. In this embodiment, an off-road type motorcycle 1 shown in Fig. 1 is explained as an example of a straddle-type vehicle to which the invention has been applied. However, the straddle-type vehicle according to the invention is not limited to this type of motorcycle, but can be a motorcycle of other types than the off-road type (such as motorcycle-type, scooter-type, of the so-called type moped, and other types of motorcycle). The invention can also be applied to a straddle type vehicle other than a motorcycle (such as ATV: off-road vehicle).

ES 2 392 589 T3

Fig. 1 is a side view of the motorcycle 1 according to this embodiment. Initially, with reference to Figure 1 the general structure of the motorcycle 1 is described. It is assumed that the front-rear and left-right directions in the following descriptions are the front-rear and left-right directions as seen from a rider seated in a seat 11.

The motorcycle 1 has a body frame 2. The body frame 2 has a main duct 3, a down tube 4 that extends downwardly from the main duct 3, and a seat support 5 that extends from the main duct 3 rearwardly. The lower end of the main conduit 3 is connected with a front wheel 7 through a front fork 6 and other components. A rearwardly extending rear arm 8 is supported in the vicinity of the lower end of the seat support 5. The rear end of the rear arm 8 is connected with a rear wheel 9. A cover 10 covering the body frame 2 is provided above the body frame 2. The seat 11 is arranged in a position slightly offset rearward from the center of the deck 10.

An engine unit 12 supported by the down tube 4 and the seat support 5 is arranged between the down tube 4 and the seat support 5. As illustrated in FIG. 2, the engine unit 12 is formed by combining an engine 13, a belt-type continuously variable transmission 14 (hereinafter referred to as "CVT (continuously variable transmission)) ( see Figure 2), a reduction mechanism 16, and other components to form a single piece. The driving force generated by the motor unit 12 is transmitted to the rear wheel 9 through power transmission means (not shown) such as a chain belt. Although engine 13 is a single-cylinder four-stroke engine in this example, engine 13 may be a multi-cylinder or two-stroke engine, for example.

The structure of the engine unit 12 is now explained with reference to Fig. 2. The engine unit 12 has the engine 13, the CVT 14, a centrifugal clutch 15, and the reduction mechanism 16. To simplify the explanation, a part of the structure of the reduction mechanism 16 is not shown in Fig. 2.

The engine 13 has a crankcase 17, a substantially cylindrical cylinder 18, and a cylinder cover 19. The crankcase 17 has two crankcase blocks: a first crankcase block 17a positioned on the left side and a second crankcase block 17b arranged on the right side. The first crankcase block 17a and the second crankcase block 17b are facing each other in the width direction of the vehicle. Cylinder 18 is connected to a diagonally upper front portion of crankcase 17 (see Figure 1 as well). The cylinder cap 19 is connected to the end of the cylinder 18.

A crankshaft 20 extending horizontally in the width direction of the vehicle is housed in the crankcase 17 of the crankshaft. The crankshaft 20 is supported by the first crankcase block 17a and the second crankcase block 17b through bearings 21 and 22.

A piston 23 is inserted into cylinder 18 so that piston 23 can slide inside. One end of a connecting rod 24 is connected with the piston 23 on the side of the crankshaft 20. The other end of the connecting rod 24 is connected with a crankshaft journal 59 disposed between a left crankshaft arm 20a and a right crankshaft arm 20b of the crankshaft 20. This structure allows the piston 23 to reciprocate within the cylinder 18 according to the rotation of the crankshaft 20.

The cylinder cover 19 has a gap 19a that connects to the interior space of the cylinder 18, and an intake port and an exhaust port (not shown) that communicate with the gap 19a. A spark plug 25 is inserted into the cylinder cap 19 and attached thereto so that the ignition area of ​​the tip of the spark plug 25 can be exposed in the gap 19a.

A cam chain chamber 26 connecting the interior of the crankcase 17 and the interior of the cylinder cover 19 is provided within the left side of the cylinder 18. A timing chain 27 is disposed within the cylinder chamber 26. cam chain. Timing chain 27 is wound around crankshaft 20 and camshaft 28. This structure allows the camshaft 28 to rotate in accordance with the rotation of the crankshaft 20 to open and close an intake valve and an exhaust valve not shown.

A dynamo box 30 housing a dynamo 29 is removably attached to the left side of the front half of the first crankcase block 17a. A transmission case 31 that houses the CVT 14 is attached to the right side of the second crankcase block 17b.

An opening is formed in the right side of the rear half of the second crankcase block 17b. The opening is closed by a clutch cover 32. The clutch cover 32 is removably attached to the second crankcase block 17b by a bolt 33.

The transmission case 31 is provided separately from the crankcase 17 of the crankshaft. The transmission case 31 has an inner case 31a that covers the inside (left side) of the CVT 14 in the width direction of the vehicle, and an outer case 31b that covers the outside (right side) of the CVT 14 in the direction width of the vehicle. Box 31a inside

ES 2 392 589 T3 is attached to the right side of the crankcase 17 of the crankshaft. The outer box 31b is attached to the right side of the inner box 31a. A belt chamber 34 is divided by the outer case 31b and the inner case 31a.

The left end of the crankshaft 20 penetrates through the first crankcase block 17a and reaches the interior of the dynamo box 30. Dynamo 29 is attached to the left end of crankshaft 20. More specifically, dynamo 29 has a stator 29b and a rotor 29a opposite stator 29b. Stator 29b is attached to dynamo box 30 so that rotation and displacement of stator 29b is prevented. The rotor 29a is fixed to a sleeve 35 that rotates with the crankshaft 20 so that the rotation of the rotor 29a is prevented. This structure allows rotor 29a to rotate relative to stator 29b in accordance with the rotation of crankshaft 20 for power generation.

CVT 14 is housed in belt chamber 34. The CVT 14 has a primary pulley 36 and a secondary pulley 37 disposed behind the primary pulley 36. The crankshaft 20 penetrates through the second crankcase block 17b and the inner case 31a and reaches the belt chamber 34. The right part of the crankshaft 20 (more precisely, the right part from the bearing 22) constitutes a primary pulley shaft 20c. Primary pulley 36 is supported by primary pulley shaft 20c. This structure allows the primary pulley 36 to rotate with the rotation of the crankshaft 20.

A secondary pulley shaft 38 which penetrates through the inner case 31a and the clutch cover 32 and reaches the inside of the crankcase 17 is disposed in the rear half of the transmission case 31. The secondary pulley shaft 38 is attached to the clutch cover 32 through a bearing 39. The secondary pulley 37 is supported by the secondary pulley shaft 38 within the belt chamber 34.

A belt 41 (such as V-belt (resin block)) is wound around the secondary pulley 37 and primary pulley 36. Therefore, when the primary pulley 36 rotates with the crankshaft 20, the generated torque is transmitted to the secondary pulley 37 through the belt 41. Then, the secondary pulley shaft 38 begins to rotate with the secondary pulley 37. The rotation of the secondary pulley shaft 38 is transmitted to the rear wheel 9 through the centrifugal clutch 15, the reduction mechanism 16, and power transmission means such as the belt and chain (not shown).

The structure of CVT 14 is explained in more detail below with reference to Figure 2. As discussed above, CVT 14 has primary pulley 36, secondary pulley 37, and belt 41, and is housed in the strap chamber 34. The primary pulley 36 has a fixed pulley element 36a and a movable pulley element 36b each having a tapered shape. The fixed pulley element 36a is fixed to the right end of the primary pulley shaft 20c so that the fixed pulley element 36a extends outwardly radially while approaching the outside (right side) in the width direction of the vehicle. The fixed pulley member 36a rotates with the primary pulley shaft 20c. On the other hand, the movable pulley element 36b is arranged in a position offset towards the center (left side) from the position of the fixed pulley element 36a and opposed to the fixed pulley element 36a. The movable pulley member 36b extends outwardly radially as it approaches the interior (left side) in the width direction of the vehicle. A projection formed at the center of rotation of the movable pulley element 36b is attached to the primary pulley shaft 20c through a collar 49. The movable pulley element 36b engages with a cam plate 60 attached to the primary pulley shaft 20c so that the cam plate 60 cannot rotate, and the rotation of the movable pulley body 36b is regulated by the cam plate 60. Therefore, the movable pulley member 36b can slide in the axial direction of the primary pulley shaft 20c, but cannot rotate with respect to the primary pulley shaft 20c. In this structure, a substantially V-shaped belt groove 36c in the cross-sectional view around which the belt 41 is wound is formed by the fixed pulley element 36a and the movable pulley element 36b, and the width of the belt groove 36c is varied by changing the position of the movable pulley element 36b with respect to the fixed pulley element 36a.

A reservoir 47 of grease (lubricant) is provided between the primary pulley shaft 20c and the collar 49. More specifically, the radius of the primary pulley shaft 20c is approximately 2mm shorter than that of other components according to this embodiment, and the The space thus produced between the primary pulley shaft 20c and the collar 49 constitutes the grease reservoir 47. One or more holes 48 through which the grease reservoir 47 communicates with the outside are formed in the collar 49. The one or more holes 48 allow the fat stored in the grease reservoir 47 to be supplied correctly to the primary pulley 36 by centrifugal force generated according to the rotation of the primary pulley 36. In this structure, a large amount of grease is supplied at the time of high-speed rotation, and thus seizing of components against each other and abrasion of the primary movable pulley 36b, collar 49 and other components can be effectively prevented. . The size and number of holes 48 can be appropriately determined based on the grease supply amount.

The method of forming the fat deposit 47 is not specifically limited. For example, the grease reservoir can be produced by piercing the collar 49 (by working the inner periphery of the collar 49 with the gouge) to expand the inside diameter of the collar 49. Alternatively, the grease reservoir 47 can be created by forming linear grooves extending in the axial direction in the primary pulley shaft 20c. In the case of the grease reservoir 47 produced by forming the linear grooves, the supply of the grease to the grease reservoir 47 is simpler than in the case of the grease reservoir 47 produced by narrowing a part of the shaft 20c of primary pulley for a shorter radius than other components. More specifically, when the grease reservoir 47 is formed by narrowing a portion of the primary pulley shaft 20c, the collar 49 attached after the

ES 2 392 589 T3 grease has been applied to the grease reservoir 47, it may come into contact with the applied grease at the time of attachment of the collar 49. In this case, there is the possibility that the grease will leak out of the grease reservoir 47 . However, when the grease reservoir 47 is produced by forming the linear grooves, the collet 49 attached after the grease has been applied to the grease reservoir 47 does not come into contact with the applied grease at the time of attachment of the collet 49 . Therefore, the fat does not leak out of the fat reservoir 47. In the case of the grease reservoir 47 formed by narrowing a portion of the primary pulley shaft 20c, the grease can be injected through the holes 48.

A cooling fan 46 is provided on the outer surface (right surface in FIG. 2) of the fixed pulley member 36a. A plurality of cam surfaces 42 extending in the radial direction are provided on the left surface of the movable pulley member 36b. The cam plate 60 is disposed on the left side of the movable pulley member 36b in a position opposite the cam surfaces 42. A plurality of substantially cylindrical (or substantially column-shaped) roller weights 44 (pressure elements) that cannot move in the circumferential direction and can move in the radial direction are provided in a space divided between the cam plate 60 and cam surfaces 42. The cam surfaces 42 are tapered so that they extend radially from the center outward as they approach the cam plate 60. The cam plate 60 has a similar taper so that it extends radially from the center outward as it approaches the cam surfaces 42. Therefore, the width between the cam plate 60 and the cam surfaces 42 decreases outwardly in the radial direction.

The secondary pulley 37 has a fixed pulley element 37a and a movable pulley element 37b positioned outside the fixed pulley element 37a in the width direction of the vehicle in a position opposite the fixed pulley element 37a. The fixed pulley member 37a attached to the secondary pulley shaft 38 extends radially outward while approaching the interior (left side) in the width direction of the vehicle. The fixed pulley element 37a rotates with the secondary pulley element 38. The movable pulley member 37b attached to the secondary pulley shaft 38 extends radially outward while approaching the outward (right side) in the width direction of the vehicle. The movable pulley element 37b is attached such that the movable pulley element 37b cannot rotate with respect to the secondary pulley shaft 38 and can slide in the axial direction. In this structure, a substantially V-shaped belt groove 37c in the cross-sectional view around which the belt 41 is wound is formed by the fixed pulley element 37a and the movable pulley element 36b, and the width of the belt groove 36c is varied by changing the position of the movable pulley element 37b relative to the position of the fixed pulley element 37a. The center of the shaft of the movable pulley element 37b is constituted by a cylindrical slip collar, and is engaged with the secondary pulley shaft 38 by means of a slotted engagement.

A helical compression spring 45 is arranged on the outside (right side) of the pulley element 37b movable in the width direction of the vehicle. Helical compression spring 45 biases movable pulley element 37b towards fixed pulley element 37a. This structure allows the width of the belt groove 37c to be minimal at the moment of low speed revolution of the engine such as under idling conditions.

The CVT 14 determines the speed change ratio based on the ratio of the force of the roller weights 44 to press the primary movable pulley element 36b toward the primary stationary pulley element 36a (to the right) with the force of the spring. Helical compression to bias the secondary movable pulley element 37b towards the secondary fixed pulley element 37a (to the left).

More specifically, when the rotational speed of the primary pulley shaft 20c is low, the width of the belt groove 37c of the secondary pulley 37 is reduced by the biasing force of the compression helical spring 45 (see pulley condition 37 secondary pulley shaft 38 shown above (maximum speed change ratio position) in FIG. 2). In this state, the belt winding diameter of the secondary pulley 37 increases, and the belt 41 is pulled towards the secondary pulley 37. Therefore, the primary movable pulley member 36b is pressed toward the cam plate 60 by the belt 41, and the width of the belt groove 36c of the primary pulley 36 is expanded (see the state of the primary pulley 36 being shown below the primary pulley shaft 20c (maximum speed change ratio state) in FIG. 2). As a result, the rate of change of speed increases.

On the other hand, when the rotational speed of the primary pulley shaft 20c becomes high, the roller weights 44 move outwardly in the radial direction upon receiving the centrifugal force. Since the distance between the primary movable pulley element 36b and the cam plate 60 narrows radially outward, the primary pulley element 36b is pressed toward the primary stationary pulley element 36a (to the right) by displacement of the roll weights 44 outward in the radial direction. Then, the primary movable pulley element 36b slides toward the primary stationary pulley element 36a, and the width of the belt groove 36c decreases (see the state of the primary pulley 36 shown above the primary pulley shaft 20c (position of minimum speed change ratio) in figure 2). In this state, the belt winding diameter of the primary pulley 36 increases, and the belt 41 is pulled toward the primary pulley 36. Therefore, the belt 41 presses the secondary movable pulley element 37b in the direction away from the secondary fixed pulley element 37a (to the right) against the biasing force of the compression helical spring 45. As a result, the secondary movable pulley element 37b slides in the direction away from the secondary fixed pulley element 37a, and the belt winding diameter of the secondary pulley 37 increases (see the condition of the secondary pulley 37 shown by under pulley shaft 38

ES 2 392 589 T3 secondary (minimum speed change ratio state) in FIG. 2). As a result, the rate of change of speed decreases.

The materials of the primary stationary pulley element 36a, the primary movable pulley element 36b, the secondary stationary pulley element 37a, the secondary movable pulley element 37b, and the cam plate 60 are not specifically limited. For example, these materials can be metals such as iron, aluminum, and stainless steel. The surfaces of these components can be processed by chrome plating or other processing.

The roller weights 44 change the distance between the cam surfaces 42 and the cam plate 60 by moving in the radially inside-out direction, and thus can be of any type as long as they can be moved in the radially inside-out direction. For example, the roll weights 44 may be spherical, roll-shaped, or otherwise. Also, the roller weights 44 can shift as they rotate, or simply slide.

The structure of the primary pulley 36, more specifically, the structures of the primary pulley member 36b and cam plate 60 according to this embodiment will now be described in more detail with reference to Figures 3 to 12.

Initially, the structure of the primary movable pulley element 36b is explained with reference to Fig. 4. A plurality of guide grooves 51 in which the corresponding roller weights 44 are disposed are formed on the rear surface of the movable pulley element 36b. primary. More specifically, the six guide grooves 51 extend radially from a protrusion 50 outwardly in the radial direction. More specifically, each adjacent pair of the six guide grooves 51 arranged to form a V shape constitutes a pair of three pairs 54 of guide grooves, and these three pairs 54 of guide grooves are provided at substantially equal intervals around the protrusion. fifty.

Each of the guide grooves 51 has the cam surface 42 and a pair of guide walls 52a and 52b. As illustrated in FIG. 2, the cam surface 42 extends radially outward while tilting toward the cam plate 60. As illustrated in FIG. 4, each of the guide walls 52a and 52b protrudes from the end side of the cam surface 42 in a direction to face each other in parallel, and extends radially along the side of end of cam surface 42. The distance between the guide wall 52a and the guide wall 52b is adjusted to substantially the same length as the height of the roller weight 44, and the roller weight 44 moves in the guide groove 51 along the walls. 52a and 52b guide in the radial direction of the primary movable pulley member 36b.

A stop 53 protruding from the cam surface 42 towards the cam plate 60 is provided at the outer end of each of the guide grooves 51 in the radial direction (see Figure 2 also). This stop 53 determines the radially outer end of the movable area of ​​the roller weight 44. Therefore, the stopper 53 regulates the further displacement of the roller weight 44 radially outward contacting the outer circumferential surface of the roller weight 44 when the primary pulley member 36b reaches the minimum speed change ratio position at wherein the primary movable pulley member 36b reduces the width of the belt groove 36c to a minimum.

Guide ribs 55 (guide elements) are provided each being disposed between the pair 54 of guide grooves and projecting from the surface of the primary movable pulley element 36b on the cam plate side toward the plate 60 of cam in the axial direction (vertical direction with respect to the blade surface of FIG. 4) at equal intervals in the circumferential direction of the primary movable pulley member 36b. Each of the guide ribs 55 extends from the outer circumference of the cam plate side surface of the primary movable pulley member 36b inwardly in the radial direction. The guide ribs 55 engage with the guide grooves 63 of the cam plate 60 as will be described later so that the guide ribs 55 can slide therein. The primary movable pulley member 36b is guided in the axial direction by sliding the guide ribs 55 in the guide grooves 63.

As illustrated in Figures 3 and 5, the cam plate 60 has a plate main body 61 made of metal (such as iron), and a plurality of glides 62 (slide elements) made of resin (such as nylon. 4-6) or other materials. More specifically, the multiple sliders 62 are provided on the outer circumferential portion of the substantially circular plate main body 61 in plan view at equal intervals along the outer circumference in the circumferential direction.

An open hole 61d through which the primary pulley shaft 20c is inserted is formed in the center of the main plate body 61. The main plate body 61 has a tapered shape expanding from the center where the open hole 61d is formed toward the primary movable pulley member 36b (see Figures 2 and 6 to 8 as well). A notch 61a is formed in the plate main body 61 at a position corresponding to each position of the guide ribs 55. More specifically, the three substantially rectangular notches 61a in plan view are formed in the outer circumferential portion of the main plate body 61 at equal intervals. For the areas where the notches 61a are formed, deep drawing is not performed. In other words, the notches 61a are placed substantially flush with other parts of the main plate body 61, and the projecting walls in the axial direction are not provided radially within the notches 61a.

As illustrated in FIG. 5, the sliders 62 are arranged in corresponding notches 61a. As discussed above, no deep drawing is performed for the notches 61a to which the sliders 62 are attached.

ES 2 392 589 T3 corresponding. Thus, as illustrated in Figures 3 and 10, the radially outer portions of the inner end surfaces 62a of the sliders 62 in the width direction of the vehicle are positioned outside their radially inner portions in the width direction of the vehicle. vehicle. More specifically, surfaces 62a are formed into sloping surfaces that extend outwardly in the radial direction while sloping outwardly in the width direction of the vehicle.

The guide groove 63 (slide grooves) is formed in each of the sliders 62. The guide ribs 55 engage with the corresponding guide grooves 63 so that the guide ribs 55 can slide therein, and thereby both the rotation of the cam plate 60 with respect to the primary movable pulley member 36b is prevented. Since the primary movable pulley element 36b is attached to the primary pulley shaft 20c so that the primary movable pulley element 36b cannot rotate as discussed above, the cam plate 60 rotates with the primary movable pulley element 36b by the rotation of the primary pulley shaft 20c. With respect to the axial direction of the primary pulley 36, the cam plate 60 is attached to the primary pulley shaft 20c so that the cam plate 60 cannot move in the axial direction of the primary pulley member 20c. Therefore, the position of the cam plate 60 with respect to the primary fixed pulley element 36a cannot be varied in the axial direction, although the position of the cam plate 60 with respect to the primary movable pulley element 36b can be varied in the axial direction.

Notches 61c extending in the circumferential direction are formed at both radially inner corners of each of the notches 61a. The respective ends of each groove 61a extending from the inside out in the radial direction curve towards the primary movable pulley member 36b in the axial direction. The curved portions 61b thus produced allow the sliders 62 to be attached to the main plate body 61 so that the sliders 62 cannot move in the axial direction.

More specifically, as illustrated in Figures 9-11, each of the sliders 62 has a slide main body 65 having the guide groove 63 and a latch portion 64 formed on the outer surface of the main body 65 of the slide. slider. The engagement between the engaging portion 64 and the curved portion 61b regulates the change of position of the slider 62 with respect to the main plate body 61 in the axial direction.

More specifically, each of the latch portions 64 has a first linear convexity 64a and a second linear convexity 64b that extend along the plate main body 61 in a direction parallel to the extension direction of the main plate body 61. plate and inclined with respect to the axial direction. The first linear convexity 64a is provided at one end of the outer surface of the slider main body 65 along the end side. The lateral surface of the first linear convexity 64a on the side of the primary movable pulley member 36b has a curved surface corresponding to the shape of a curve 61e of the curved portion 61b, and contacts the curve 61e by surface contact. The side surface of the first linear convexity 64a on the side opposite the primary movable pulley member 36b is flush with the end surface of the slider main body 65. Thus, the end surface 62a of the slider 62 is substantially flush with the tapered surface of the main plate body 61 on the side opposite the primary movable pulley member 36b. The guide grooves 63 extend from the area where the guide grooves 63 are substantially flush with the tapered surface of the main plate body 61 on the side opposite the primary movable pulley member 36b toward the drive member 36b. primary mobile pulley.

The second linear convexity 64b is located at a position slightly offset to the other end of the outer surface of the main slider body 65 from its center. The side surface of the second linear convexity 64b on the side opposite the primary movable pulley member 36b comes into contact with an end surface 61f of the curved portion 61b. It is preferable that the first linear convexity 64a and the second linear convexity 64b are arranged in parallel to each other in view of the simple attachment and separation of the slider 62.

As illustrated in FIG. 10, the slider 62 has a substantially trapezoidal shape in side view having an axial length L1 of the radially outer portion of the slider 62 less than an axial length L2 of the radially inner portion of the slider 62. In other words, the radially inner area of ​​the slider main body 65 further extends from the portion where the second linear convexity 64b is provided toward the primary movable pulley member 36b. Thus, an extension 65a is formed which extends from a position displaced towards the primary movable pulley member 36b from the second linear convexity 64b in the slider main body 65.

Since the radially outer portion of the end surface 62a of the slider 62 is positioned outside its radially inner portion in the width direction of the vehicle, the length of the engagement portion between the cam plate 60 and the guide rib 55 at the extension direction of the cam plate 60 becomes relatively large. More specifically, since the end surface 62a of the slider 62 is an inclined surface that extends outwardly in the radial direction while it is inclined outwardly in the width direction of the vehicle, the length of the engagement portion between the cam plate 60 and guide rib 55 in the extension direction of cam plate 60 becomes relatively large.

More specifically, as illustrated in FIG. 12, the end surface 62a has a tapered section according to this embodiment, and thus a length L3 of the engagement portion between the cam plate 60 and the guide rib 55 on the extension direction of cam plate 60 (see Figure 12 (a)) can be made larger than a

ES 2 392 589 T3 corresponding length L4 in the related art structure in which the deep drawn processed part for attachment of the slider 162 of the main plate body 161 crosses the axial direction at right angles (see Figure 12 (b )). Consequently, guide groove 63 and guide rib 55 more rigidly engage with each other, and primary movable pulley member 36b slides more smoothly and stably relative to cam plate 60.

Since the radially outer portion of the end surface 62a of the slider 62 is positioned outside the radially inner portion of the end surface 62a in the width direction of the vehicle, the need for deep drawing of the main plate body 61 is eliminated. . Thus, costs are reduced and the need for complicated and difficult deep drawing for the plate main body 61 is eliminated. Accordingly, the cam plate 60 can be more easily manufactured at a lower cost than the cam plate having the structure requiring deep drawing as in the related art. Particularly, the service life of a mold (metal mold) used to form the cam plate 60 is lengthened, and the costs for molding the cam plate 60 are reduced. As a result, the belt-type continuously variable transmission 14 which is manufactured simply at a low cost, and the motorcycle 1 which is thus easily manufactured at a low cost can be obtained.

According to the plate main body 161 in the related art for which deep drawing is performed, it is necessary to attach the slider 162 at a position remote from the boss by an amount corresponding to the deep drawing. In this case, it is difficult to increase the length of the slider 162 in the radial direction enough to extend an innermost portion in the radial direction. According to this embodiment, however, the length of the slider 62 that does not require deep drawing can be increased in the radial direction sufficiently to reach an innermost portion in the radial direction. That is, since the plate main body 61 does not require deep drawing, the length L3 of the engaging portion between the cam plate 60 and the guide rib 55 in the extension direction of the cam plate 60 is increased. Thus, the guide groove 63 and the guide rib 55 engage each other more rigidly, and the primary movable pulley member 36b can slide more smoothly and stably with respect to the cam plate 60. Furthermore, since the contact area between the slider 62 and the guide rib 55 is relatively large, the surface pressure applied to the slider 62 is relatively low. As a result, the durability of the slider 62 made of a material having a relatively low hardness can be increased.

According to this embodiment, the guide groove 63 extends from its portion substantially flush with the tapered surface of the main plate body 61 toward the primary movable pulley member 36b. Thus, a large contact area between the guide groove 63 and the guide rib 55 is ensured. Consequently, the engagement between the guide groove 63 and the guide rib 55 becomes especially rigid, and the sliding of the primary movable pulley member 36b relative to the cam plate 60 is considerably stabilized. Furthermore, according to this structure, the contact area between the slider 62 and the guide rib 55 can be particularly increased. Therefore, the durability of the slider 62 made of a material having a relatively low hardness can be further improved.

The slider 62 is attached to the plate main body 61 by engagement between the latch portion 64 and the curved portion 61b formed by curving each end of the groove 61a extending from the inside out in the radial direction. More specifically, the slider 62 is attached to the main plate body 61 by surface contact between the surface of the curved portion 61b and the side of the slider 62 in the state that the engaging portion 64 comes into contact with the bend. 61e and the end surface 61f squeeze the curved portion in the axial direction. Therefore, the large contact area between the slider 62 and the plate main body 61 is ensured, and the slider 62 is rigidly fixed to the plate main body 61 according to this embodiment. Furthermore, the surface pressure of the contact surface between the plate main body 61 and the slider 62 is relatively low. Accordingly, the durability of the slider 62 made of a material having a relatively low hardness such as resin can be increased. For further improvement of the durability of the slider 62, a guard element (such as metal) may be interposed that contacts the slider 62 with a contact area greater than the contact area between the slider 62 and the main body 61. plate between slider 62 and plate main body 61.

According to this embodiment discussed above, the guide groove 63 extends from its portion substantially flush with the tapered surface of the main plate body 61 toward the primary movable pulley member 36b. Thus, as illustrated in Fig. 12 (c), a sufficient engagement area is ensured between the guide rib 55 and the guide groove 63 even though the main plate body 61 is moved further up from the end. radially inward of the guide rib 55 in FIG. 12 (c) (more specifically, in the direction away from the surface of the primary movable pulley member 36b that opposes the cam plate 60). That is, since the guide groove 63 extends from the main plate body 61 toward the primary movable pulley member 36b as illustrated in Figures 12 (c) and 12 (d), a large range of travel can be ensured. of the primary movable pulley member 36b with respect to the cam plate 60, which range is equivalent to that of the related art structure using the deep drawing shown in FIG. 12 (d).

Particularly, as illustrated in Fig. 12 (a), the contact area between the guide groove 63 and the guide rib 55 can be increased in the state that the primary movable pulley member 36b is away from the plate. Cam 60 forming the slider main body 65 having a substantially trapezoidal shape in side view having the length L2 of the radially inner part in the axial direction longer than the length L1 of its part

ES 2 392 589 T3 radially outer, that is, forming the extension 65a extending from a position displaced towards the primary movable pulley element 36b from the second linear convexity 64b. In this case, the length of the guide rib 55 in the axial direction becomes relatively short, and a comparatively wide range of movement of the primary movable pulley member 36b relative to the cam plate 60 in the axial direction is ensured. Accordingly, the primary pulley 36 can be made compact and thin. In other words, the CVT 14 provided according to this embodiment can vary the speed ratio relatively large.

According to this embodiment, the latch portion 64 is disposed along the end side of the outer side of the slider main body 65 on the side opposite the primary movable pulley member 36b as illustrated in Fig. 9 and other figures. Thus, the upper end surface of the slider 62 is substantially flush with the tapered surface of the cam plate 60. That is, the slider 62 does not protrude away from the primary movable pulley member 36b from the tapered surface of the cam plate 60. Therefore, as illustrated in FIG. 2, positional interference between the inner case 31a of the transmission case 31 and the slider 62 is avoided. Consequently, the CVT 14 provided according to this embodiment can be made more compact.

According to this embodiment, the curves 61e are formed by curving the respective ends of the groove 61a extending from the inside out in the radial direction, and the first linear convexity 64a is provided so that the side of the first linear convexity 64a on the side of the primary movable pulley member 36b has a curved surface corresponding to the shape of the curve 61e of the curved portion 61b. Therefore, the slider 62 is effectively prevented from projecting toward the side opposite the primary movable pulley member 36b with respect to the axial direction from the tapered surface of the cam plate 60. This advantage is particularly preferable in view of the miniaturization of the CVT 14.

The following modifications and changes to the structure may be made in accordance with the preferred embodiment of the invention described above. The plate main body 61 and the slider 62 (slide member) can be integrally formed with each other. However, when the shape of the slider 62 is particularly complicated, it is preferable that the main plate body 61 and the slider 62 are provided separately from each other for ease of manufacture.

According to this embodiment, the primary pulley 36 has the primary fixed pulley element 36a and the primary movable pulley element 36b. However, the primary pulley 36 may have two primary movable pulley elements arranged opposite each other. More specifically, a cam plate and an additional pressure element may be provided on the right side of the primary fixed pulley element 36a so that the primary fixed pulley element 36a can be displaced in the axial direction of the primary pulley shaft 20c according to the displacement of the pressure element.

According to this embodiment, the end surface 62a of the inner portion of the slider 62 in the width direction of the vehicle extends outwardly radially while it is inclined outwardly in the width direction of the vehicle. However, the end surface 62a need not have such an inclined surface as long as the radially outer portion of the end surface 62a is positioned outside its radially inner portion in the width direction of the vehicle. For example, end surface 62a may have a stepped shape in side view as illustrated in Figure 13.

The straddle-type vehicle according to the invention is not limited to the off-road-type motorcycle discussed in this embodiment, but can be a motorcycle of different types from the off-road type (such as motorcycle-type, scooter-type, the called moped type and other types of motorcycle). The invention is also applicable to a straddle type vehicle other than a motorcycle (such as ATV: off-road vehicle).

The description "the end surface 62a and the inner surface of the plate main body 61 in the width direction of the vehicle are level with each other" in this specification includes the state in which the end surface 62a and the inner surface of the plate main body 61 in the width direction of the vehicle are offset from each other to such an extent that no problem occurs in practical use as well as the state in which the surface 62a of The end and the inner surface of the plate main body 61 in the vehicle width direction are perfectly level with each other.

The invention finds application in a straddle type vehicle having a belt type continuously variable transmission.

DESCRIPTION OF REFERENCE NUMBERS AND SYMBOLS motorcycle motor unit motor belt-type continuously variable transmission (CVT)

ES 2 392 589 T3 crankshaft

20c primary pulley shaft primary pulley

36a primary fixed pulley element

36b primary movable pulley element secondary pulley belt cam surface roller weight guide groove stop guide rib cam plate plate main body

61st notch

61b curved part slider

62a end surface guide groove hooking part main body of slider

65th extension