Machine tool

IS 2 170 754 T5

DESCRIPTION

Machine tool.

The invention relates to a machine tool according to the preamble of claim 1.

Such a machine tool is known from JP 4 365 529 A.

A machine tool, comprising a machine frame, a workpiece holder placed on the machine frame to hold a part to be machined, a tool-holder spindle movably placed on the machine frame, for holding a tool, a first carriage, in which the tool-holder spindle is placed and which can move along a first axis and is guided on a first carriage-holder support, a second carriage, that can be displaced along a second axis that extends transversely with respect to the first axis and that surrounds the first trolley support support and that is guided in a second trolley support configured as a yoke that surrounds a second central opening, forming the second support carriage part of the machine frame, and a first drive and a second drive for carrying out a relative movement between the tool and the part in the direction of the axes is known from document US 4,987,668, in this machine the second carriage support forming a closed gantry, in whose two columns the first carriage support is guided.

Therefore, the present invention aims to improve a machine tool of the generic kind indicated, so that it has a construction that is as stable as possible and that the highest possible dynamics can be achieved.

This objective is solved in a machine tool of the kind described at the beginning with the characteristics indicated according to claim 1.

The advantage of the solution advocated in the invention therefore consists in that with this solution a robust and rigid construction is achieved for the positioning of the tool-holder spindle.

The highest possible dynamics can be achieved in the movement of the tool-holder spindle, if at least the first drive and the second drive comprise two linear electric motors, aligned parallel to the respective axis and located at a distance from each other in the transverse direction, if the respective carriage, which can be moved by these linear motors, runs between the two linear motors and if a control is provided, that simultaneously drives the linear motors for the movement of the respective carriage.

By means of the concept proposed in the present invention of using two linear motors aligned parallel to the axis, which are used at the same time to move the carriage, great dynamics can be achieved for driving the carriage, since this way no longer there are the usual limitations of rotary spindle drives. Furthermore, the problems common to known screw drives in terms of play, elasticity, friction and wear are thus eliminated.

In addition to the high acceleration and high speeds achieved in this way, other special advantages are also the long travel paths and the positioning accuracy.

Further advantages are achieved by the use of two linear motors operating simultaneously, since these simply supply particularly high acceleration forces for highly dynamic carriage movement.

The two linear motors can work in the most diverse ways.

Thus, an advantageous solution possibility provides that the two linear motors work together as a single numerical control (NC) axis. However, despite the common drive as the numerical control axis, separate power supply lines are advantageously provided here. This possibility can be implemented in a way that is economically favorable in terms of control technology.

As an alternative to this, it is envisaged that the two linear motors can be driven as independent numerical control (NC) axes. This means that each of the linear motors has its own control for the numerical control axis and its own power supply. This has the advantage that the movement of the two linear motors can thus be better synchronized with each other.

This is particularly advantageously possible if each linear motor has its own path measurement system.

In particular, a parallel movement of the carriage can be carried out by means of an active control of the linear motors, so that, on the one hand, essentially no transverse forces act on the carriage guides any longer, which could cause edging. of the car.

Linear motors can be built in the most diverse ways. Single comb linear motors are conveniently employed.

In a preferred solution, linear motors have primary part and secondary part as linear motor parts, aligned parallel to a plane.

A particularly compact form of construction in the use of linear motors of this kind can be achieved if the plane, in which the motor parts extend, is located transversely to the transverse direction.

In order to be able to effectively evacuate the heat from the linear motors, it is furthermore advantageous that the linear motors are each located to one side in the outer areas of the carriage and of a carriage support.

The arrangement of the linear motors is particularly advantageous if they are placed on opposite outer sides of the carriage support or of the carriage itself. With this solution, an optimal evacuation of the heat produced by the linear motors to the outside is possible, and on the other hand, a form of construction of the trolley or the trolley support is possible that is as compact as possible in the direction of the respective axis.

Regarding the driving of the carriage, no concrete indications have yet been given here when explaining the previous embodiments. For example, it is conceivable to guide the carriage in a main guide device. However, it is particularly advantageous, especially as regards the accuracy and precision of the carriage driving, that the carriage is guided in two main guide devices, parallel to each other and located at a distance from each other.

In order to achieve a compact construction and on the other hand to create the possibility of optimal cooling of linear motors, as already mentioned above, it is advantageously provided

ES 2 170 754 T5 that the main guiding devices are positioned between the linear motors.

With this arrangement of the linear motors, located externally with respect to the main guide devices, stability problems could occur due to the forces acting between the parts of the linear motors.

These stability problems are advantageously solved by positioning each of the linear motors respectively between a main guide device and an additional guide device, so that both guide devices act between the carriage and the respective carriage support. Therefore, the placement of the additional guide devices allows a robust guiding of the engine parts relative to each other and a sufficient rigidity with the smallest possible mass of the carriage and the carriage support, and therefore a high dynamics.

To achieve optimum cooling, linear motors are preferably provided with a cooled primary and secondary part.

A refrigeration of this kind can be carried out in the most diverse ways. An exemplary embodiment preferably provides that the cooling of the primary and secondary parts is carried out by means of cooling channels in support elements for the primary and secondary parts, so that these can be cooled by means of direct contact with the respective elements. support on which they lean.

The cooling channels are preferably traversed by a stream of a cooling medium, which can be cooled by means of a cooling device to a defined temperature.

In connection with the explanation of the above embodiments, only the way in which optimum carriage dynamics can be achieved has been discussed. By using electric linear motors, both acceleration and braking are possible with these linear motors.

However, especially for safety reasons, it is advantageous if the carriage can be held in a fixed position in addition additionally by means of a brake device.

The braking device is preferably designed here as a mechanically acting braking device. The braking device here serves in particular as an automatic braking device, which automatically brakes the carriage when predetermined carriage positions are reached.

For this, it is preferably provided that the braking device can be actuated by means of an end position switch, which therefore brakes and firmly holds the carriage, independently of the activation of the linear motors, when an end position set by the limit switch.

As an alternative or in addition to this, it is advantageously provided that the braking device is designed as a safety and protection element in the event of a power failure or emergency stop.

To do this, the braking device can preferably be actuated by means of a safety switch for cases of power failure or an emergency stop switch, so that the braking device brakes and firmly holds the trolley in the event of a power failure. cut off the electrical power supply for linear motors or if the emergency stop switch is actuated.

It is particularly expedient, especially in order to effectively apply the greatest possible braking forces, that the carriage can be fixed by means of two braking devices located at a distance from each other in the transverse direction. In this way, the carriage can be braked particularly effectively and abrupt braking of the carriage can preferably be avoided.

In an advantageous embodiment of a machine tool constructed according to the invention, provision is made for the workpiece holder to be held on a third carriage so that it can be moved in a third direction transversely to the first and second directions.

For this, the workpiece holder can rotate around an axis, preferably with a rotary drive, with respect to the machine frame, so that the workpiece can be placed in different rotational positions around a rotary axis or it can be placed in rotary motion around this axis, for example in a similar way to a spindle.

A particularly advantageous solution provides that the rotary drive is configured as a numerical control axis (NC), so that the rotary movements can be carried out with exactly determinable angles or rotary machining.

As regards the rotary drive, it is particularly advantageous here that it is a direct drive, that is to say that no intermediate gear is provided between a drive motor and the workpiece holder.

The advantages of such a direct drive are that gear problems such as play, friction, etc. are suppressed and high dynamics can be achieved.

In combination with a direct drive, a particularly preferred solution in terms of achievable accuracy is achieved if the rotary drive is provided with a direct measuring system, which detects the rotary positions of the workpiece holder.

In order to be able to precisely position and fix the workpiece holder in the various rotational positions, it is preferably provided that the rotary drive has a brake device, with which it is possible to fix the workpiece holder in any rotary position for machining the workpiece.

Preferably, especially in a configuration of the machine tool as a machining center, the rotary drive is configured as a rotary table, with which the workpiece holder can rotate about a vertical axis.

To do this, the workpiece holder can be released and fixed in a housing of the rotary table, so that the part, together with the workpiece holder, is fixed on the rotary table, then machined and then can be transported out together with the workpiece holder. .

The fixture can preferably be clamped hydraulically in the rotary table housing.

The workpiece carrier is here preferably constructed as a pallet, on which the workpiece is held.

In particular in the case of a rotary table around a vertical axis, it is advantageously provided

ES 2 170 754 T5 for this rotary table to rest on a carriage, which in turn can be moved on a longitudinal bench of the machine frame, which includes a carriage support.

In the case of an advantageous version of a machine tool made according to the invention, the second carriage support is placed in the form of an upright on a bed of the machine.

A third axis, located transversely with respect to the first and second axes, is formed by a carriage movable along a longitudinal bed placed on the bed of the machine. This division of the axes allows optimal stability and, especially in the case of linear drives, allows to obtain an optimal distribution of the masses to achieve the greatest possible dynamics in all axes.

The longitudinal bed is in this case preferably surrounded by the bed of the machine.

A particularly robust construction is achieved if two arms of the Y-shaped bed are located next to the longitudinal bed, the arms being attached, at their ends farthest from the longitudinal bed, to the upright of the machine.

In another embodiment carried out according to the invention, provision is made for a work space of the machine tool to be surrounded and closed by a cell. In order to allow a highly dynamic movement of the carriage, it is provided in this case that a limiting wall of the cell is formed by at least one partition or closing shield attached to the carriage and extending away from the carriage in the direction of movement of this and that, in all positions of the axis of the carriage, reaches in its direction of extension at least up to a wall limiting the workspace in the direction of extension.

For this, it is advantageous if the enclosure wall of the cell is formed by two partitions or closing shields, which extend in opposite directions to each other.

Advantageously, it is provided here that a tool placed on the first carriage in its movement traverses a space existing between the two partitions or closing shields.

In order to be able to optimally cover this movement space as well and to be able to carry out highly dynamic movements, it is preferably provided that this space can also be closed, at least in one direction, by means of a partition or closing shield that can be moved by the car.

This partition or closing shield can be guided in any way desired. Preferably, this partition can be guided by means of longitudinal guides on both sides of the movement space.

A particularly advantageous embodiment of a machine tool constructed according to the invention provides that two partitions or closing shields are provided on the second carriage, extending in opposite directions to each other, and that another partition or wall is placed on the first carriage. closing shield extending in one direction, while a closing wall of telescopic elements is located in the other direction, and that the partition and the telescopic wall form a final boundary wall of the cell.

As regards the construction of the partitions or closing panels, no specific indications have been given so far. To achieve good stability, a partition is configured as a lightweight construction plate, which has a front layer and a rear layer of sheet metal and reinforcing bodies with hollow spaces located between the two layers, to give the partition rigidity.

The reinforcing body is conveniently a layer of corrugated sheet. But, it is also possible to make it as a structure with cells or in the form of a honeycomb, etc.

A solution in which the front and rear layers are made of aluminum is particularly advantageous. Even better is that also the reinforcing body, to give rigidity to the partition, is made of aluminum and preferably that the reinforcing body and the layers are glued together.

Another advantageous example of embodiment has a tool magazine located outside the cell.

The tool magazine is preferably configured as a magazine wheel in the shape of a Ferris wheel, with storage positions for tools located on its circumference.

In order to be able to carry out a tool change easily and as quickly as possible with the tool holder, in the case of a cell surrounding the workspace, a side wall with a swing door is provided.

This swing door is preferably designed as a double swing door with two door leaves.

The door leaves must be able to be opened as an option, since in order to pass through the double swing door as quickly as possible, it is necessary that both door leaves open as quickly as possible. For this, provision is preferably made that the door leaves can be brought into an open position by pushing the tool holder.

For this purpose, damping elements are preferably provided in the door leaves, which reduce the acceleration forces acting on the door leaves by the tool holder.

In order that the door leaves are closed again in the simplest possible way and can be kept in this closed position, it is preferably provided that the door leaves are pressed by means of spring elements in the direction towards their closed position.

Since, if the two door leaves are opened rapidly, there is a danger that the leaves will rebound elastically from their open position due to collision with a stop, it is preferably provided that each door leaf is provided with a brake device, preferably in the form of a friction brake device, which slows the free movement of the door leaf.

Other characteristics and advantages of the solution proposed in the invention are the subject of the following description, as well as the representation in drawings of some embodiments.

The attached drawings show:

- in figure 1 a general perspective view of a machine tool made according to the invention;

- in figure 2 a view from above in the direction of an arrow A in figure 1;

IS 2 170 754 T5

- in figure 3 a view from above in the direction of an arrow B in figure 1;

- in figure 4 a view from above in the direction of an arrow C in figure 1;

- in figure 5 a section through a carriage of the Z axis with actuation of the axis of rotation;

FIG. 6 shows a perspective representation of a second embodiment;

- in figure 7 a detail in section along the line 7-7 of figure 6;

- in figure 8 a detail in section along the line 8-8 of figure 6; Y

- in figure 9 a detail in section along the line 9-9 of figure 6.

A first example of embodiment represented in FIG. 1 for a machine tool made according to the invention comprises a frame of the machine, designated as a whole with the reference number 10, on which a part 12 can be placed. For machining the part 12 by means of a tool 14, the tool 14 is clamped on a tool-holder spindle 16, which for its part can be displaced on the frame 10 of the machine in an X direction and in a Y direction. Additionally, the part 12 can also move in a Z direction with respect to the tool spindle 16 and perpendicular to the X and Y axes, so that as a whole the part 12 and the tool 14 can move along three axes. located perpendicular to each other, specifically the X axis, the Y axis and the Z axis, for machining part 12.

In order to be able to move the tool spindle 16 along the X and Y axes, the tool spindle 16 is attached to a carriage 18 movable on the Y axis, which in turn can be moved in the Y direction on a carriage support 20, configured as a yoke with a central opening 22. The tool spindle 16 here extends with a rear portion 24 away from the tool 14, passing through the central opening 22 (Figures 2 and 3). The central aperture 22 is therefore configured so that the tool spindle 16 can move unimpededly and without colliding with the edges of the central aperture 22 along its maximum travel path Y, preset by the possibility of movement of the carriage 18 of the Y axis with respect to the carriage support 20.

The carriage support 20 is surrounded by a carriage 26 movable on the X axis, which for its part is movably held along the X axis on a post 28. The upright 28 is here also configured as a yoke and has a central opening 30, through which the rear part of the tool spindle 24 passes, the central opening 30 being configured so that the tool spindle 16 can move in the opening, without colliding, towards all possible positions along the X and Y axes.

The upright 28, as part of the frame 10 of the machine, is placed on a bed 32 of the machine, also surrounded by the frame 10 of the machine and having a longitudinal bed 34, which extends parallel to the Z axis and through therefore perpendicular to a plane formed by the X axis and the Y axis, moving away from the upright 28. For the robust union of the upright 28 with the longitudinal bed 34, the bed 32 of the machine has two arms 36 that move away from the longitudinal bed forming a Y, on whose ends 38 farthest from the longitudinal bed 34 the upright 28 sits. , the ends 38 being located under the vertical support beams 40 of the yoke of the upright 28.

A carriage 42 movable on the Z axis is driven on the longitudinal bed 34 and parallel to the Z axis, on which a rotary axis drive 44 is positioned, with which the workpiece can rotate about a B axis.

The rotary shaft drive 44, together with a receiving surface 46 for a workpiece holder 48, forms a rotary table, designated as a whole with reference numeral 50, for the workpiece holder 48, which is preferably configured as a pallet for placement of part 12.

Axis B is here located parallel to the plane formed by axis X and by axis Y, and is preferably perpendicular to an axis 52 of tool spindle 16.

As shown in Figures 2 and 3, the carriage 18 movable on the Y-axis comprises a bridge 70, on which the tool-holder spindle 16 is placed. The bridge 70 carries guide carriages 74 and 76 on a back side 72, which are positioned at a distance from each other on a front side 78 of the carriage support 20 and are guided on guide rails 80 and 82 which extend parallel to the Y axis. The guide carriages 74 and 76, together with the guide rails 80 and 82, form main guide devices 84 and 86 for the carriage 18 movable on the Y axis, which are preferably located symmetrically with respect to the axis 52 of the spindle. .

On both sides of the main guide devices 84 and 86, specifically on the farthest sides of the tool spindle 16, a linear motor 88 or 90 is respectively located on each side, both serving together to move the movable carriage 18 on the axis. Y in the direction of the Y axis, and running both motors simultaneously.

The two linear motors 88 and 90 are located respectively on the sides of the carriage support 20, specifically such that they are adjacent to a lateral surface 92 or 94 respectively of the carriage support 20 and extend with their winding planes 96 parallel to the Y-axis direction, and parallel to the Z-axis direction.

Each of the linear motors comprises a primary part 98, which is mounted on a clamping flange 100 of the carriage 18 movable on the Y axis on a side facing the lateral surface 92 or 94. For this, the clamping flange 100 is it extends from an outer end 102 of bridge 70 approximately parallel to, surrounding side surface 94.

On the trolley support 20 and facing the primary part 98, a secondary part 106 is arranged by means of a support element 104, which rests on the support element 104 on one side facing the clamping flange 100, while support member 104 is supported on side surface 94.

To support the clamping flange 100 against the forces acting perpendicular to the winding plane 96 between the primary part 98 and the secondary part 106, the clamping flange 100 is guided on its side furthest from the bridge 70 by means of an additional guide device 108, comprising a guide carriage 110, attached to the clamping flange 100,

ES 2 170 754 T5 and a longitudinal guide 112 resting on the lateral surface 94 and extending parallel to the Y axis. This additional guide device 108 thus exactly guides the clamping flange 100 in a defined alignment with respect to the lateral surface 94 of the carriage support 20 and therefore to the primary part 98 at a defined distance from the secondary part 106, specifically in conjunction with the main guide devices 84 and 86.

For cooling the primary part 98 and the secondary part 196 of each of the linear motors 88 and 90, cooling channels 114 or 116 are provided respectively in the clamping elements for the motors, that is, in the clamping flange 100. for the primary part 88 and on the support element 104 for the secondary part 106, so that both the primary part 98 and also the secondary part 106 can be cooled by means of the clamping element that serves as a support respectively, that is, by the clamping flange 100 and by the support element 104. The cooling channels 114 and 116 are traversed by a stream of a cooling medium, which is cooled by a cooling device to a defined temperature.

The ignition of the two linear motors 88 and 90 is carried out by means of a connection device 118 provided jointly for the two linear motors 88 and 90, which is a numerical control (NC) command for the axes, with power lines current 120 anyway independent, it being possible for the connection device 118 to be preset the position along the Y axis that the moving carriage 18 in the Y axis must reach in its movement by means of a main control 122 of the machine.

To detect the actual position of the carriage on the Y axis, a Y axis measurement system 124 is provided, which extends parallel to the Y axis, and which is positioned on the front side 78 of the carriage support 20, specifically between the spindle tool holder 16 and main guide device 86, and has a travel recorder 126, as well as a travel probe 128, the travel recorder 126 being placed on the trolley support 20 and the travel probe 128 being attached to the bridge 70.

The Y-axis measurement system 124 detects the position of the movable carriage 18 in the Y-axis with respect to the Y-axis, and sends this data through a line 130 to the control device 118, which thus receives a preset value of the actual position on the Y axis, whereby, after a comparison with the position on the Y axis to which it is to be reached, predetermined by the machine control 122, it provides a winding current for the respective linear motor 88 or 90, which circulates through a supply line 132 or 134 to the respective linear motor 88 or 90.

To increase the dynamics of the movement of the mobile carriage 18 on the Y axis in the direction of the Y axis, the force of gravity, which acts on the mobile carriage 18 on the Y axis due to the mass of the tool spindle 16 of the mobile carriage 18 on the Y axis, it is compensated by means of a pneumatic counterweight 140, comprising a pneumatic cylinder 142, which is held in the carriage support 20 and whose piston rod 144 acts on the bridge 70 preferably in the area of ​​the tool-holder spindle 16. The pneumatic cylinder 142 is subjected to such a pressure that it essentially compensates for the force of gravity that it acts on the mobile carriage 18 in the Y axis, so that, by means of the linear motors 88 and 90, it is only necessary to provide essentially the acceleration forces.

In order to be able to additionally fix the carriage of the Y-axis in defined positions along the Y-axis, a brake 150 is further provided between the main guide device 84 and the tool spindle 16, comprising a brake member 152 that actuates a shoe brake and which for its part is fastened to the bridge 70, and a brake slat 154, which is fastened to a front side 78 of the trolley support 20.

The brake 150 serves to fix the movable carriage 20 on the Y axis when an emergency stop switch is actuated or in the event of a power failure, in the latter case the actuation of the brake 150 takes place automatically.

The carriage 26 movable in the Y axis, which surrounds the carriage support 20 is supported for its part in a displaceable manner on the upright 28 configured in the shape of a yoke, specifically by means of two main guide devices 170 and 172, each of the which comprises a guide carriage 174 and a guide rail 176, the guide rail 176 being supported on a front side 178 of the upright 28, while the guide carriage 174 is supported on a rear side 180 of the mobile carriage 26 on the X axis.

The two main guide devices 170 and 172 are here aligned parallel to the X-axis and extend at a distance from each other, preferably in the area of ​​two transverse yoke beams 184 or 186 respectively of the yoke-shaped upright 28, which form a trolley support.

Two linear motors 190 and 192 are provided to drive the movable carriage 26 in the X axis, the winding plane 194 of which extends parallel to the X direction and parallel to the Z direction. For this, the two linear motors 190 and 192 are also located on the sides of the transverse beams 184 and 186, the lower linear motor 190 being located below the lower transverse beam 184, while the upper linear motor 192 is located above the upper cross member 186.

Each of the linear motors 190 and 192 comprises a primary part 198, held by a clamping flange 196 placed on the mobile carriage 26 on the X axis, opposite to which there is a secondary part 200, which in turn is clamped. by a support element 202, which is positioned on a lateral surface 204 of the transverse beams 184 or 186. The clamping flange 196 here also surrounds the lateral surface 204 of the respective transverse beam 184 or 186.

In addition, an additional guide device 206 is provided for supporting the clamping flange 196, comprising a guide carriage 208 and a guide rail 210, the guide carriage 208 being fastened to the clamping flange 196 and the guide rail 210 attached to the respective crossbar 184 or 186. The additional guide device 206 is hooked for this also at one end of the respective clamping flange 196, further away from the carriage 26 of the X-axis, so that the respective linear motor 190 or 192 is located between the additional guide device 206 and the respective main guide device 170 or 172, and the primary part 198 is supported on both sides with

ES 2 170 754 T5 tra the secondary part 200 by means of the respective additional guide device 206 and the respective main guide device 170 or 172.

In the same way that has already been described in relation to the linear motors 88 and 90, the clamping flange 196 is provided with cooling channels 212 and the support element 202 is provided with cooling channels 214, which are also traversed by the cooling medium, which is cooled by the cooling device to a defined temperature.

For the operation of the two linear motors 190 and 192, two connection devices 220 and 222 are provided, with their own current supply for each of them for the respective linear motor 190 and 192, so that this current supply system provides electrical current to linear motors 190 and 192 through power lines 224 or 226 respectively, the position being pre-fixed along the X axis by means of the main control 122 of the machine.

To detect the exact position along the X axis of the mobile carriage 26 on the X axis, two measuring systems 228 and 230 are provided, the measuring system 228 being located near the linear motor 190, preferably on the side farthest from the upright. 28, and the measurement system 230 being close to the linear motor 192, preferably on the side farthest from the crossbar 186.

Each of the two measurement systems 228 and 230 comprises a travel detector 232 and a travel probe 234, the travel detector 232 being connected to the upright 28 and the travel probe 234 connected to the mobile carriage 26 on the X axis.

For the connection device 220 for the linear motor 190 the measuring system 228 located close to the motor is provided, while for the connection device 222 for the linear motor 192 the measurement system 230 is provided.

Due to the large distance between the linear motors 190 and 192 in the direction of the Y axis, and therefore also the large distance between the measuring systems 228 and 230, the allocation of its own measuring system for each of the connection devices 220 and 222 serve so that these two connection devices 220 and 222 can work completely independently of each other, as two independent controls by numerical control for the axes, but at the same time they can work simultaneously, so that each linear motor 190 or 192 starts in a regulated way up to the position of the X axis required by the control 222 of the machine, according to the respective actual measurement values ​​of the corresponding measurement system 228 or 230. In this way you can achieve an active parallel driving of the mobile carriage 26 on the X axis, specifically parallel to the Y axis, so that the parallel alignment of the mobile carriage 26 on the X axis with respect to the Y axis is actively carried out by means of of the command.

For fixing the movable carriage 26 on the X axis at positions along the X axis there are additionally also two brakes 250 and 252, each of which comprises a brake element 254 with brake shoes and a brake slat 256 , the brake slat 256 of the brake 250 being fastened to the crossbar 184, while the brake slat of the brake 252 is fastened to the crossbar 186, and the brake elements 254 of both the brakes 250 and 252 are located on the rear side 180 of the movable carriage 26 on the X axis.

Both brakes 250 and 252 are designed to fix the carriage on the X axis, when an emergency stop switch is actuated or in the event of a power cut.

The longitudinal bench 34 comprises two support beams 290 and 292 located at a distance from each other and parallel to the Z axis, forming a carriage support, and have main guide devices 294 and 296 for the mobile carriage 42 on the Z axis. Each of the main guide devices respectively comprises a guide rail 298 supported on the support cross member 290 or 292 and a guide carriage 300 movable on the guide rail 298 and secured on the carriage 42 movable on the Z axis.

The carriage 42 movable on the Z axis comprises a casing 302 of the rotary axis drive 44, in which a rotor is supported in a rotational manner around the B axis by means of a rotary support 306, a rotor designated as a whole with the number of Reference 304.

The rotor 306 is driven directly by a motor, designated as a whole by the reference numeral 308, the stator part 310 of which is supported on the casing 302 and the rotor part 312 of which is rotatably supported on the rotor, the part being of stator 310 and rotor part 312 positioned in the casing 302 between the turning bracket 306 and the guide carriage 300.

For detecting the rotational positions of the rotor 304 relative to the housing 302, a rotary pulse transmitter 314 is radially located inside the motor 308. This negative impulse transmitter generator 314 sends the actual rotational position of the rotor 304 with respect to the casing 302 to a connection device 316, which in turn supplies the motor 308 with electrical current through a power line, in such a way that that the turning movements can be performed as movements in the B axis controlled by the numerical control (NC).

The various rotational positions of the motor 308 are preset by means of the machine control 122, which sends them to the connecting device 316 of the rotary shaft.

To fix the workpiece holder, the housing 46 is provided on the rotor 304, which has roller bearings 320 positioned at a distance from each other and which support the workpiece holder on a lower side 322. Furthermore, the roller bearings 320 penetrate into grooves 324 of the workpiece holder, so that the workpiece holder, by means of the movement of the housing 46 in the direction towards the casing 302, can also be pushed in this direction and can be placed on support elements. 326 on rotor 304. These support elements 326 serve for the centering and for the exact alignment of the workpiece holder 48 with respect to the rotor 304, to achieve an exact positioning of the workpiece holder 48 with respect to the rotor 304 and therefore with respect to the B axis and the Z axis. The bearing elements 326 preferably form bearing surfaces that extend transversely with respect to the B axis and also have centering bolts 330, which engage in the corresponding centering holes 332 made in the fixture 48, to position the fixture in a defined manner with respect to to axis B on rotor 304.

To move the housing 46 towards the housing 302 or to move it away from it, in a

In the upper part of the rotor 304, there is provided a piston 334 held vertically in the housing 302, on which a cylinder 336 is guided, surrounded by the rotor 304, movable in the direction of the axis of rotation or of the axis B. This cylinder 336 can be displaced by applying pressure with a hydraulic medium on the spaces 335a or 335b of the cylinder and serves as a support for the housing surface 46 with the roller bearings 320.

The supply of hydraulic fluid to the cylinder spaces 335a and 335b in the rotor 304 is carried out by means of a fixed supply line 338 located in a central position and passing through a piston rod 334 and extending from the casing 302, up to the rotor 304 and which, at the height of the cylinder spaces 335a and 335b, connects the cylinder spaces 335a and 335b with their hydraulic channels through rotating supply conduits.

To fix the rotor 304 to the housing 302, a brake 340 is also provided, which has a brake element 342 and a brake flange 344, the brake flange 344 being rigidly connected to the rotor 304 and the brake element being supported. brake 342 securely on housing 302.

With the brake 340 it is possible to fix the rotational position of the part 12, resting on the workpiece holder 48, for its machining by means of the tool 14.

To move the carriage 42 along the Z axis, two linear motors 360 and 362 are provided along the Z axis, the winding planes 364 of which extend in the same plane parallel to the Z axis and the Y axis. The two motors Linear lines 360 and 362 are then located on one side next to the cross member, in the region of the lateral surfaces 366 that are farthest from each other.

Each of the linear motors 360 and 362 comprises a primary part 368, which is clamped on a clamping flange 370, the clamping flange 370 being itself clamped on the carriage on the Z axis and extending along the sides of the cross members. 290 and 292 and overlying the lateral surfaces 366 of said cross members. Opposite the primary part 368 is located a secondary part 372, which in turn rests on a support element 374, which in turn is fastened on the respective lateral surface 366.

Furthermore, cooling channels 371 or 375 respectively are provided in the clamping flange 370 and in the support element 374, which are traversed by the flow of the cooling medium in the same way as in the X-axis or in the Y-axis.

In the same way that occurs in the Y axis, as well as in the X axis, the support of the clamping flange 370 takes place here by means of an additional guide device, designated as a whole with the number 376, comprising a carriage guide rail 378 and a guide rail 380, the guide rail 380 being attached to the respective cross member 290 or 292 and the guide carriage 380 being rigidly attached to the clamping flange 380.

The forces acting between the primary part 368 and the secondary part 372 are therefore absorbed here, in the same way as in the Y axis or in the X axis, by means of the respective main guide device 294 or 296 and the corresponding device additional guide 376.

To fix the movable carriage 42 on the Z axis, brakes 381 and 383 are also provided, which preferably act between the longitudinal bed 34 and the clamping flanges 370 and are shaped in the same way as the brakes 250 and 252.

For the detection of the movement of the moving carriage 42 in the Z axis along the Z axis, each of the linear motors 360 and 362 has a measuring system 384 or 386 respectively, the measuring systems being located respectively on one side. interior 388 or 390 of the respective support cross member 290 or 292, in order to be as close as possible to the respective linear motor 360 or 362.

Each of the measurement systems 384 and 386 comprises a path detector 392, fixedly attached to the longitudinal bed 34, as well as a path probe 394 attached to the carriage 42 movable in the Z axis.

For the operation of the two linear motors 360 and 362, each of them has a connection device 396 or 398 and each of these connection devices 396 has a path measurement system 384 or 386 to detect the real position in the direction Z. Both connection devices 396 and 398 receive from the machine control 122 the data on the position to which they should move along the Z axis and then compare this position with the respective real positions detected by the measurement systems 384 and 386 .

Both connection devices 396 and 398 work independently of each other, so that in this way an active parallel alignment of the carriage can be carried out in the Z axis with respect to the X axis, exactly as described in relation to the connection devices 220 and 222.

In a second embodiment of a machining center built according to the invention, represented in Figure 6, for example for the solution proposed according to the first embodiment, a workspace 400, in which machining of the part 12 by means of the tool 14, is surrounded by a cell 402, which comprises a front wall 404 essentially perpendicular and parallel to the XY plane, which is located opposite the tool-holder spindle 16. Between the front wall 404 and the movable carriage 18 on the Y axis, the workpiece holder 48 can be moved along the Z axis. The cell 402 also comprises two side walls 406 and 408, located at a distance from each other, between which are You can move the carriage on the Z axis, designated as a whole with the reference number 42. These side walls 406 and 408 extend from the front wall 404 in the direction of the carriage 18 movable on the Y axis, equipped with the tool spindle 16 and movable both in the Y direction and also in the X direction.

A rear closing wall of the cell 402, located opposite the front wall 404, is formed by two closing shields or partitions 410 and 412 attached to the mobile carriage 26 on the X axis, which extend from a movement space 414 located in the direction of the Y axis for the tool-holder spindle 16, respectively in the direction of the X axis, so that, on both sides and in all positions of the X axis of the carriage 26 movable on the X axis, the partitions rest on the rear side edges 416 or 418 respectively of the side walls 406 or 408, or they protrude outside these in the direction of the X axis on a side opposite to that of the working space 400.

The two closing shields or partitions 410 and 412 are rigidly fastened to the mobile carriage 26 on the X axis, by means of a system of bars not shown.

ES 2 170 754 T5 in the drawing, and form a partially rear closing wall of cell 402.

This closing wall is completed by means of an upper closing wall 420, which closes the movement space 414 above the tool-holder spindle 16 and is configured as a closing shield or partition, and a lower closing wall 422 located below the spindle. tool holder 16 and closing the movement space 414.

The upper closing wall 420 is a plate attached to the carriage 18 movable in the Y axis, as shown in Figure 7, and is guided in grooves 424 and 426 of the edge slats 428 and 430, which limit the space of movement 414 and extend in the direction of the Y axis. The extension of the plate 420 is chosen in this case so that, with an upper edge 432, it is flush in all positions of the Y axis of the tool spindle 16 with the upper edge 434 of the shields or partitions 410 and 412, or protrudes above these upward.

In contrast, the bottom closure wall 422 is a so-called telescopic type liner, shown in Figure 8, comprising a number of closure plates 440 that telescopically overlap each other and can be moved one over the other and guided in a number of grooves 442 or 444 respectively of the edge slats 428 or 430, placed consecutively in the direction of the Z axis. One of the closure plates 440, the one located in the highest position, is attached to the carriage on the Z axis, while the plate located in the lowest position of the closure plates 440 is attached to a lower part 450 of cell 402, bottom 450 forming a bottom sealing surface of cell 402.

As shown in Figures 7 and 8, the two closing shields or partitions 410 and 412 are lightly constructed plates, having two outer layers 411 placed parallel to each other and a corrugated inner layer 413, placed between the two and joined. to them, preferably glued, and respectively composed of thin sheet metal, preferably aluminum sheet.

In addition, for the introduction of parts with a workpiece holder 48 in the workspace 400, each of the side walls 406 and 408 is provided with a door 452 and 454 respectively, the respective door being located on a transport path 456 for the workpiece holder 48, said track extending at a distance from the movable carriage 18 on the Y axis, as well as from the machining position 458 of the workpiece 14, parallel to the direction of the X axis through the cell 402.

Outside the cell 402 there is also installed a tool magazine, designated as a whole with the reference number 460, comprising a magazine wheel 464 in the shape of a Ferris wheel, which can rotate about an axis 462, the axis 462 being located preferably parallel to axis 52 of the spindle. On this magazine wheel 464 there are arranged accommodation stations 466 for a large number of tools.

The magazine wheel 464 is located in this case so that a delivery position 468 is within the zone of movement of the Y / X axes of the tool spindle 16, so that the tool spindle 16 together with the tool 14 it can be inserted directly into the delivery position 468, thanks to its mobility in the plane of the Y / X axes.

For this, in the rear area, located next to the rear edge 416 of the side wall 406, there is provided a double swing door 470, shown in detail in Figure 9, which has two door leaves 476 or 478, which they can tilt around axes 472 or 474 respectively parallel to the Z axis and are supported on the side wall 406, so that when they are in the closed state they have front edges 480 or 482 located at a short distance from each other, so that in the closed state of the reciprocating double door 470, the cell 402 is closed. These door leaves 476 and 478 are pressed in the direction of their closed position by means of two spring elements 484 and 486, the position being closed fixed by means of two stops 488 or 490 against which are supported two tiltable arms 492 and 494 pressed by spring elements 484 and 486. The spring elements 484 and 486 are preferably hooked onto the pivoting arms for this.

The opening of the double swing door 470 is now carried out by moving the tool spindle 16 to a defined position 496 on the Y axis, and then moving it in the direction of the X axis against the door leaves 476 and 478, the leaves 476 being and 478 of the door provided for this purpose with damping elements 498 or 500, preferably in the area of ​​its front edges 480 or 482. In this way, the tool spindle 16 presses with its outer casing 502 on each of the door leaves 476 and 478 until it reaches an open position, represented in figure 9 by intermittent broken lines, then enters the delivery position 468, delivers the tool 14 to the magazine wheel and, after turning the magazine wheel 464, takes a new tool 14 from the magazine wheel from the delivery position 468. In the delivery position 468 (represented in the drawing with intermittent lines) the tool spindle is positioned so that its outer casing 502 keeps the door leaves 476 and 478 in the open position.

Each of the door leaves 476 and 478 is additionally also provided with a friction brake 504, which comprises a friction wheel 506 fixedly attached to the respective door leaf 476 or 478 and which in turn rests on a friction jaw 508, which is pressed against friction wheel 506 by means of a spring-elastic element 510. In this way, by rapidly opening the two door leaves 476 and 478, the door leaves 476 and 478 are prevented from bouncing back towards their closed position, furthermore, in this way a slow closing of the doors is ensured. leaves 476 and 478 of the door.