Vehicle height adjusting device

'7~ 1 VEHICLE HEIGHT ADJUSTING DEVICE 3 BACKGROUND OF THE INVENTION 4 1.

Field of the Invention:

The present invention relates to a vehicle height 6 adjusting device having an elongate resilient member 7 provided as a suspension component, having a vertical 8 resilient force, and extending transversely of a vehicle.

9 2.

Description of the Relevant Art:

Generally, conventional vehicle height adjusting 11 devices include a damper comprising a shock absorber which 12 has an additional air chamber serving as an actuator for 13 effecting vehicle height adjustment and also comprising a 14 coil spring. Laterally spaced suspensions have such dampers independen-tly. Such a height adjusting device is 16 disclosed in Japanese Laid-Open Patent Publication No. 6117 150809, for example 18 For carrying out vehicle height adjustment, 19 therefore, there have heretofore been required dedicated dampers for making vehicle height adjustment only, each , 21 damper~somprising a shock absorber which has an additional 22 air chamber serving as an actuator for effecting vehicle : ::

23 height adjustment and also comprising a coil spring. To :

24 give a commercially available vehicle a vehicle height adjusting capability, its dampers are replaced with dampers 26 having~ height~adjusting~alr chambers, and the basic 27 s~tructure~of ~suspensions of -the vehicle may have to be :

:

7~ l modified. HeretoEore, since the dedicated dampers or 2 height adjusting actuators are independently associated 3 with the laterally spaced suspensions, respectively, there 4 is a limitation on eEforts to make the suspensions smaller and lighter.

6 SUMMARY OF THE INVENTION 7 It is an object of the present invention to 8 provide a vehicle he.ight adjusting dévice which can employ 9 a damper comprising a shock absorber only with no coil spring, can provide a stabilizer function, allows a vehicle ll height adjusting capability to be added easily to an 12 existing vehicle without modifying existing dampers and the 13 basic structure of suspensions of the vehicle in any way, 14 permits height adjusting actuators to be located in a centralized position so as to make the suspensions smaller 16 and lighter, and can ensure substantially the same 17 suspension capability when the vehicle height is adjusted 1~ as that when the vehicle height is not adjusted.

l9 : : According to the present invention, there is provided a vehlcle helght adjusting device including a ~: :

21 resilient member.having an outer end coupled to a wheel 22 support member and an inner ~end:supported on a vehicle 23 body, the resilient member having a vertical resilient 24 force and serving: as a:suspension component, and load means disposed between the resilient member and the vehicle body 26 ~ for~applying a vertical bending stress to the resilient 27 ~member:~to~dlsplace the resilient member for thereby varying ~ 2 - ~ :: ~ 1 the height of the vehicle body.

2 According to the present invention, there is also 3 provided a vehicle height adjusting device incLuding a 4 Another vehicle height adjusting device includes an elongate resilient member e~tending transversely of a 6 vehicle body and having opposite ends coupled respectively 7 to two laterally spaced wheel support members, the 8 resilient member having a vertical resilient force and 9 serving as a suspension component, retaining members supporting an intermediate portion of the elongate 11 resilient member slidably and swingably on the vehicle body 12 at at least two spaced points on the intermediate portion, 13 and load means for applying a vertical bending stress to 14 the resilient member to displace the resilient member for thereby varying the height of the vehicle body.

16 The above and further objects, details and 17 advantages of the present invention will become apparent 18 from the following detailed description of preferred 19 embodiments thereof, when read in conjunction with the accompanying drawlngs.

21 BRIEF DESCRIPTION OF THE DRAWINGS 22 FIG. :1 is a schematic front eleva-tional view of a 23 suspension incorporating a vehicle height adjusting device 24 according to a first embodiment of the present invention;

FIG, 2 is~a schematic front elevational view of a 26 suspension:incorporating a vehicle height adjusting device : : :

27 according to a second embodiment of the present invention;

: - 3 Y~ - ~ , ~- ,'. ,, 7~ 1 FIG. 3 is a schematic front elevational view of 2 two laterally spaced suspensions incorporating a vehicle 3 height adjusting device according tc a third embodiment of 4 the present invention;

FIG. 4 is a schematic ro-nt elevational view oE 6 two laterally spaced suspensions incorporating a vehicle 7 height adjusting device according to a fourth embodiment of 8 the present invention:

9 FIG. 5 is a schematic front elevational view showing the manner in which a concentrated load is appiled 11 to the center of a resillent member by a load means in the 12 third and fourth embodiments;

13 FIG. 6 is a schematic front elevational view 14 showing the manner in which different concentrated loads are appiled at two spaced positions to an intermediate 16 portion of a resilient member by a load means in the third 17 and fourth embodiments;

18 FIG. 7~is a schematic front elevational view 19: showing the manner in which unlform equally d1stributed loads are appiled to an intermediate portion of a resilient 21 membe~r by a load means:in~:the thi~rd and fourth embodiments 22 ;FIG. 8 is a schematic front elevational view 23 showing the manner in which irregularly distributed loads 24 are app~iled:at two:spaced positions to an intermediate portion of a~resilient member by a load means in the third 26 and~fourth~embodiments;

27~ FIG; ~9 1s~a schematic front elevational view - ~ : , .

1 showing a fluid-filled enclosure used as the load menas in 2 the emboidment of FIG. 3;

3 FIG. 10 is a schematic front elevational view 4 showing a fluid-filled enclosure used as the load menas in the emboidment of FIG. 4;

6 FIG. ll(a) is a cross-sectional view taken along 7 line XI - XI of FIGS. 9 and 10, showing the condition when 8 the pressure of the fluid in the enclosure is lower;

9 FIG. ll(b) is a cross-sectional view taken along line XI - XI of FIGS. 9 and 10, showing the condition when 11 the pressure of the fluid in the enclosure is higher; and 12 FIG. 12 is a schematic front elevational view 13 showing a modification of the enclosure illustrated in 14 FIGS. 9 and 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 16 ~FIG. 1 shows a vehicle suspension incorporating a 17 vehicle height adjusting device according to a first .A 18 embodiment of the~inventlon. Thé suspenslon shown together 19 with one of laterally spaced road wheels is of the double-wishbone type. A road wheel l~is rotatably 21 supported~an an axle 2 mounted on a support member or 22 knuckle 3 pivotally connected at an upper end thereof to 23 the outer end of an upper arm 4 of the suspension. The 24 suspension a~so includes a lower arm which is constructed o a resilient member or leaf spring 11 having a vertical 26~; resillent~force~and~extending transversely of the vehicle.

27 More specificaily, the leaf spring 11 has a slightly :

~ 5 1 upwardly curved intermediate portion of an arcuate shape.

2 The outer end of the leaf spring 11 is pivotally connected 3 to the lower end of the knuckle 3 at a supporting point A.

4 The leaf spring 11 has its inner end fixedly supported on a vehicle body 9 at a supporting point s.

6 Although not shown in FIG. 1, a load means of any 7 desired type is interposed between the vehicle body 9 and 8 the intermediate portion of the leaE spring 11, and a g damper comprising a shock absorber only is associated with the suspension.

11 Since the lower arm, which cooperates with the 12 upper arm 4 in constructing the double-wishbone suspension, 13 is constructed of the leaf spring 11, the portion of the 14 suspension pivotally coupled to the leaf spring 11 at the outer supporting point A near the road wheel 1 is normally 16 urged downwardly under the resiliency of the arcuate leaf 17 spring 11 which is supported on the vehicle body 9 at the 18 inner supparting point B. Therefore, as the leaf spring 11 19 doubles as the lower arm, the suspension is made lightweight. The suspension can also employ dampers each 21 comprising a shock absorber only with no coil spring.

22 When an upward bending stress, for example, is 23 applied to the leaf spring 11 at a portion or in a certain 24 range thereof by the load means, as indicated by the arrow F, the leaf spring 11 fixed to the vehicle body 9 at the 26 lnner supporting point B is elastically deformed, lifting 27 its outer supporting point A, i.e., moving the road wheel 1 ~ ; - 6 1 upwardly with respect to the vehicle body 9. The vehicle 2 height above ground is thus lowered. Conversely, the 3 vehicle height above ground is increased by applying a 4 downward bending stress to the leaf spring 11.

FIG. 2 shows a second embodiment in which a lower 6 arm 5 has an outer end pivotally coupled to the lower end 7 of a knuckle 3 and a leaf spring 12 is provided separately 8 from the lower arm 5. The leaf spring 12 has an outer end g pivotally coupled to an intermediate portion of the lower arm 5 at a supporting point A and an inner end fixedly 11 supported on a vehicle body 9 at a supporting point B.

12 The arrangement shown in FIG. 2 operates in the 13 same manner and offers the same advantages as the 14 construction shown in FIG. 1, except that the leaf spring doubles as the lower arm in FIG. 1.

16 According to a third embodiment shown in FIG. 3, 17 two laterally spaced suspensions;each identical to that of 18 the first embodiment are interconnected by a leaf spring 13 19 which is elongate transversely of the vehicle. The leaf spring 13 is of an arcuate shape with its intermediate 21 portion curved upwardly, and is longer than the leaf 22 springs 11, 12 shown in FIGS. 1 and 2. The opposite ends 23 of the leaf spring 13 are pivotally coupled at supporting 24 points A to the lower ends of laterally spaced knuckles or support members 3 supporting road wheels 1, respectively, 26 through axles 2. The leaf spring 13 has its intermediate 27 port:on slidably and swingably supported on a vehicle body ~ - 7 . ~ , 7~ 1 9 at two laterally spaced supporting points C by means of 2 retaining members 21, respectively. The leaf spring 13 3 doubles as two lower arms.

4 Although not shown, a load means of any desired type is interposed between the vehicle body 9 and a central 6 area, for example, of the intermediate portion of the leaf 7 spring 11 between the supporting points C, and a damper 8 comprising a shock absorber only is associated with each of 9 the suspensions.

Since the lower arms 5 are constructed of the 11 common leaf spring 13, the portions of the suspensions 12 pivotally coupled to the leaf spring 13 at supporting 13 points A on the opposite ends of the leaf spring 13 near 14 the road wheels 1 a~e normally urged downwardly under the resiliency of the arcuate leaf spring 13 w,hich is supported 16 on the vehicle body 9 at the two laterally spaced 17 supporting points C on the intermediate portlon of the leaf 18 spring 13, with the load means interposed between the leaf 19 spring 13 and the vehicle body 9 between the supporting points C. Therefore, the common leaf spring 13 doubling as 21 the lower arms gives the suspensions a stabilizer function, 22 the load mean~s is shared by the suspensions, and the 23 9uspensions;are made lightweight. The suspensions can also 24 ~employ dampers~each comprising a shock absorber only with no coil spring.

26 ~ ~When an upward bending stress, for example, is 27 ;applled;to the~leaf~spring 13 at its center or within a , ~ ~ - 8~ 1 certain intermediate range L between the supporting points 2 C by the load means, as indicated by the arrow F, the leaf 3 spring 13 is elastically de~ormed, lifting its intermediate 4 portion. The supporting points A on the opposite ends of the leaf spring 13 near the road wheels 1 are then lowered 6 about the supporting points C, so that the road wheels 1 7 are moved downwardly with respect to the vehicle body 9, 8 resulting in an increase in the vehicle height above 9 ground. Conversely, when a downward bending stress is imposed on the intermediate portion o the leaf spring 11, 11 t:he vehicle height above ground is reduced.

12 FIG. 4 shows a fourth embodiment in which two 13 laterally spaced suspensions each identical to that of the 14 second embodiment are interconnected by a leaf spring 14 which is elongate transversely of a vehicle. More 1~ speciically, the elongate leaf spr~ing 14, which is 17 separate from two laterally spaced lower arms 5, has 18 opposite ends pivotally coupled at supporting points A to 19 intermediate portions of the lower arms 5, respectively.

The lea spring 14 has an intermediate portion slidably and 21 swingably supported on a vehicle body 9 at two laterally 22 spaced supporting points C by means o retaining members 23 21, respectively.

24 The arrangement shown in FIG. 4 operates in the 25~ same manner and offers the same advantages as the 26 construotion sh;own;in FIG. 3, except that the leaf spring 27 doubles as the lower arms in FIG. 3.

g, :

7G l 1 In the third and fourth embodiments, the elongate 2 leaf springs 13, 14 are employed and a vertical bending 3 stress is applied by the load means to a limited range L of 4 the intermediate portion of the leaf sprinys 13, 14.

Therefore, the supporting points A near the road wheels 1 6 can be displaced a relatively large distance by a 7 relatively small vertical displacement of the intermediate 8 range L.

Inasmuch as the load means is disposed between 9 the supporting points C on both sides of the intermediate portion of the leaf springs 13, 14, height adjusting 11 actuators are not required to be associated independently 12 with the road wheels 1 but the load means is located in a 13 centralized position. This allows the suspensions to be 14 smaller and lighter.

lS The leaf spring 13, 14 may be subjected to a 16 centralized load F appli~d to the center of the leaf spring 17 13, 14, as shown in FIG. 5. However, independent vehicle 18 height adjustments may be effected at the laterally spaced 19 road wheels 1 by applying different centralized loads F, F' to two laterally spaced points on the leaf spring 13, 14 21 between the supporting points B, as shown in FIG. 6.

22 Instead of the centralized loads, uniform equally 23 distributed loads F may be applied to the leaf spring 13, 24 14 within an intermediate range L to avoid stress concentration on the leaf spring 13, 14, as shown in FIG.

26 7. Alternatively, as shown in FIG. 8, irregularly 27 distributed loads F, F ' may be impressed on the leaf spring - 1 0 ~ , .

.

7~ 1 at two laterally spaced areas in the intermediate range L 2 to avoid stress concentraion and also to permit independent 3 vehicle height adjustments at the road wheels 1.

4 The leaf spring or resilient member may be coupled to the upper arms or may double as the upper arms.

6 The present invention is applicable to not only double7 wishbone suspenions but also strut suspensions. The leaf 8 spring may be supported on the vehicle body at four 9 laterally spaced points on the intermeidate portion of the leaf spriDg.

11 The load means may be disposed upwardly of the 12 leaf spring or both upwardly and downwardly of the leaf 13 spring. A leaf spring extending longitudinally of the 14 vehicle may be used for vehicle height adjustment.

A load means which can be employed in the vehicle 16 height adjusting devices according to the aforesaid 17 embodiments will be described below.

18 FIG. 9 shows a load means for use with the 19 vehicle height adjusting device according to the third embodiment shown in FIG. 3~. The retaining members or means 21 21 by which the elongate leaf spring 13 is supported on the 22 vehicle body 9 at the supporting points C, C have a beam or 23 box 22 disposed below the leaf spring 13 and extending 24 substantlally~parallel to the leaf spring 13 in the transverse direction of the vehicle. A load means 31 26 comprising an enclosure 32 illed with a fluid is disposed 27 between the leaf spring 13 and the beam 22 and extends :

:: ~ ~: ' l transversely of the vehicle.

2 The enclosure 32 may be unexpandable and the 3 fluid filled therein may be a gas which is a compressible 4 fluid. Alternatively, the enclosure 32 may be expandable and the fluid filled therein may be a liquid which is a 6 noncompressible fluid.

7 A gas or a liquid is injected by a pump or the 8 like (not shown) into the enclosure 32 of the load means 31 9 which is prevented from moving downwardly by the beam 22 that is integral with the vehicle body 9, for thereby ll increasing the internal pressure in the enclosure 32 from 12 the condition of FIG. ll(a) to the condition of FIG. ll(b).

13 By thus applying an upward bending stress to the leaf 14 spring 13 between the supporting points C, the leaf spring 13 is elastically deformed, lifting its intermediate 16 portion. The supporting points A on the opposite ends of 17 the leaf spring 13 near the road wheels 1 are then lowered 18 about the supporting points C, so that the road wheels 1 19 are moved downwardly with respect to the vehicle body 9, resulting in an increase in the vehicle height above 21 ground. Conversely, the vehicle height above ground is 22 lowered by reducing the internal pressure in the enclosure 23 32 ~rom the condition of FIG. ll(b) to the condition of 24 FIG. ll(a) for thereby weakening the upward bending stress applied to the leaf spring 13 between the supporting points 26 C by the load~means 31.

27 ~Since equally~distributed loads are applied to , ~ - 12 1 the leaf spring 13 between the supporting points C by the 2 load means 31 comprising the fluid filled in the enclosure 3 32, stress concentration on the leaf spring 13 can be 4 avoided, and the supporting points A on the opposite ends of the leaf spring 13 can be displaced a relatively large 6 distance in response to a relatively small displacement of 7 the leaf spring 13 between the supporting points C. In 8 addition, the load means 31 is positioned between the 9 laterally spaced supporting points C on the intermediate portion of the leaf spring 13, i.e., height adjusting 11 actuators are not associated independently with the road 12 wheels 1 but the load means is located in a centralized 13 position. This allows the suspensions to be smaller and 14 lighter.

If a bending stress were applied to the leaf 16 spring 13 by means of an actuator such as a hydraulic 17 cylinder unit, because the leaf spring 13 and the actuator 18 would be coupled through a fixed point, the supporting 19 points C would also be substantially fixed, and vertical swinging movement of the supporting points A on the 21 opposite ends of the leaf spring 13 would be limited by the 22 fixed supporting points C. Therefore, the leaf spring 13 23 would be elastically deformed in different modes. With the 24 vehicle height adjusted, the suspension capability would become different from that which would be if no vehicle 26 helght adjustment were effected, and the stabilizer 27 function would also be impaired.

~ - 13 1 According to the present invention, the load 2 means 31 comprises a compressible fluid filled in an 3 unexpandable enclosure 32, or a noncompressible fluid 4 filled in an expandable enclosure 32, for example, so that S the load means 31 can follow the bending displacement of 6 the leaf spring 13 between the supporting points C 7 dependent on the internal pressure in the enclosure 32.

8 Therefore, even when the vehicle height i5 adjusted, the 9 portion of the leaf spring 13 between the supporting points C can be kept substantially in a free state.

lL More specifically, with the vehicle height 12 adjusted, the portion of the leaf spring 13 between the 13 supporting points C can freely be bent upwardly when the 14 road wheels 1 rebound, while the load means 31 is following lS the bending displacement of the leaf spring 13 except when 16 the load means 31 excessively rebounds under reactive 17 forces due to the internal pressure of the fluid in the 18 enclosure 32. Downward bending displacement of the leaf 19 spring 13 between the supporting points C when the road wheels 1 bound is substantially freely effected while the 21 load means 31 is following the bending displacement of the 22 leaf spring 13 through either compression of the 23 compressible fluid sealed in the unexpandable enclosure 32 24 under the load, or expansion of the expandable enclosure 32 in which the noncompressible fluid is sealed. Therefore, 26 vertical swinging movement of the supporting points A on 27 the opposite ends of~the leaf spring 13 upon bounding and ~: :

: - 14 )~ ' " ' ` 7~ 1 rebounding the road wheels 1 remains to be such rnovement 2 which allows the leaf spring 13 to glide and swing at the 3 supporting points C.

4 Therefore, even with the vehicle height adjusted, the leaf spring 13 is elastically deformed in substantially 6 the same mode as that which would be if the vehicle height 7 were not adjusted. Consequently, substantially the same 8 suspension capability as that which would be if the vehicle 9 height were not adjusted can be maintained, and the stabilizer function can also be maintained.

11 FIG. 10 shows a load means for use with the 12 vehicle height adjusting device according to the fourth 13 embodiment illustrated in FIG. 4. The retaining members or 14 means 21 have a beam or box 22 accommodating a fluid-filled enclosure 32. The load means shown in FIG. 10 operates in 16 the same way and offers the same advantages as those of the 17 load means shown in FIG. 9.

18 According to a modification shown in FIG. 12, two 19 load means 31 which are substantially the same as the load means 31 described above may be disposed in the beam 22 at 21 laterally spaced loaations, and the fluid pressures in the 22 enclosures 32 may suitably be selected for independent 23 vehicle height adjustment at the road wheels 1.

24 : With the present invention, as described above, a suspension component is constructed of a resilient member ..

26 having: a vertical resilient force, and the resilient member 27 has portlons coupled to road wheels and an lntermediate 15 ' ~ , , ` .

'7~ 1 portion supported on the body of the vehicle at areas 2 spaced from the coupled portions. ThereEore, dampers each 3 comprising a shock absorber only with no coil spring may be 4 employed. Furthermore, a load means is provided for applying a vertical bending stress to the resilient member 6 to displace the resilient member for varying the height of 7 the vehicle. Accordingly, a vehicle height adjusting 8 capability can easily be added to an existing vehicle 9 without modifying the dampers and the basic structure of suspensions of the vehicle.

11 Where the load means comprises a fluid filled in 12 an enclosure, e.g., a compressible fluid filled in an 13 unexpandable enclosure, or a noncompressible fluid filled 14 in an expandable enclosure, stress concentration on the resilient member can be avoided and the load means is 16 capable of following bending displacement of the resilient 17 member. Therefore, when the road wheels bound or rebound 18 with the vehicle helght adjusted, the resilient member is l9 elastically deformed in substantially the same mode as that which would be if the vehicle height were not adjusted. As 21 a result, substantially the same suspension capability as .

22 that which would be if the vehicle height were not adjusted 23 can be maintained.

24 Although there have been described what are at present considered to be the preferred embodiments of the 26 present invention, it will be understood that the invention 27 may be embodied in other speciflc forms without departing .

- 16 : :

1 from the spirit or essential characteristic.s thereo~. The 2 present embodiments are thereEore to be considered in all 3 aspects as illustrative, and not restrictive. The scope of 4 the invention is indicated by the appended claims rather than by the foregoing description.

11 12 13 14 16 17 18 1 9 21 :: :

22 23 :: :

24 26 27` .