Electromechanical drive module

Abstract

In order to provide an electromechanical drive module as an alternative for hydraulically operating the piston, it is proposed that the piston and the axial unit are provided, the piston being mounted in a rotationally fixed but longitudinally displaceable manner relative to the axial unit, and the axial unit being arranged in the housing in a rotatable but immovable manner in the direction of the longitudinal axis. The two elements engage into each other via a chute in which the guide pin is guided and which has a control cam that is inclined in the longitudinal axis. The rotation of the axial unit, which can be generated by means of the electric motor, is converted into the piston stroke due to the shape of the control cam in the chute and the anti-rotation bearing of the piston.

Description

Technical Field

[0001] The invention relates to a drive module comprising a housing and a piston which is mounted in a rotationally fixed manner relative to the housing in the direction of a longitudinal axis but is longitudinally displaceable and which serves for a compressive or tensile actuation, in particular a tensioning means. Background Art

[0002] It has long been known that various types of tensioning devices are used on machine tools, which require an actuating force to actuate them. Such an actuating force is usually applied by means of a hydraulic cylinder, which is used in the machine tool and whose piston can be connected to the tensioning device in order to enable loading with tensile and compressive forces.

[0003] Thus, for example, a force tensioner, such as a tensioning tong or a tensioning mandrel, is placed on the headstock of a lathe in the area of ​​the workspace. Behind it, i.e. facing away from the workpiece tensioned in the force tensioner, a hydraulic cylinder follows and transmits force to the force tensioner via its tension rod.

[0004] However, for hydraulic applications it is usually necessary to supply hydraulic oil, so that hose lines must be introduced. Therefore, it is always necessary to work with multiple media, thus usually at least with electrical energy and hydraulic pressure. Summary of the invention

[0005] Against this background, the object of the present invention is to provide a drive module which overcomes the disadvantages of the prior art and constitutes an equivalent alternative to the known hydraulic pistons.

[0006] This object is achieved by a drive module according to the features of independent claim 1. Exemplary embodiments of such a drive module can be gathered from the subsequent dependent claims.

[0007] In this regard, a drive module is provided, which comprises a housing and a piston which is mounted in a rotationally fixed manner with respect to the housing in the direction of a longitudinal axis but can be longitudinally displaced, the piston being used for pressure or tension actuation, in particular a tensioning device. According to the invention, the drive module is characterized in that the piston is surrounded by an axial unit which is mounted rotatably but immovably in the direction of the longitudinal axis, wherein the axial unit is actuated electrically in the direction of rotation and a guide groove is formed between the piston and the axial unit, in which guide groove at least one guide pin is guided along a control cam which is inclined in the direction of the longitudinal axis in order to generate the piston stroke.

[0008] The invention therefore provides that a piston is provided for force transmission, which exerts the same type of pressure on the tensioning means, or that the invention can also be used freely if other applications are desired, such as in hydraulic pistons. For this purpose, the piston is mounted in such a way that it cannot be rotated relative to the housing or the axial unit, but can only be disconnected or pulled apart in the direction of the longitudinal axis, i.e. in the direction of the coupled device (e.g. the tensioning means), but also in the direction of any other application. This is achieved, for example, by providing at least one guide pin on the piston, which guide pin is guided in a guide groove, i.e. a guide slot, of the axial unit.

[0009] In the sense of kinematic reversal, it can also be provided that at least one guide pin is fastened to the axial unit and engages in a guide groove or guide slot of the piston. However, if the first-mentioned solution is discussed below, this should also always apply to the reverse configuration.

[0010] The axial unit can only rotate around the longitudinal axis, but cannot move in the direction of the longitudinal axis or in the opposite direction. Therefore, during the rotation of the axial unit, at least one guide pin moves along the guide slot. If the guide slot is an annular groove, the piston fixedly connected to the guide pin will not move. Due to the shape of the guide slot with a control cam, which has an inclination relative to the longitudinal axis, the guide pin is pressed in the direction of the control cam during the rotation of the axial unit and thus moves the piston connected to it. This works in both directions. The piston stroke corresponds to the rise of the control cam on the path in the guide slot passed by during the rotation of the axial unit.

[0011] Due to the purely electric drive of the axial unit, only the current supply to the drive module is required for the force transmission; no other media are necessary.

[0012] In a specific embodiment, the axial unit of such a drive module can have two cam disks, which together form a guideway, wherein the cam disks are connected to each other in a rotationally fixed manner with at least one supporting sleeve interposed therebetween. In particular, the cam disks can be simple circular disks in the radial direction, which in the longitudinal direction along their edges respectively form the walls of the guideway channel, so that the guide pin is guided between the walls lying opposite one another and is pressed in the direction of the longitudinal axis during the rotation of the axial unit.

[0013] Furthermore, the guideway can be divided into a plurality of guideway segments of the same type. In this case, the forces occurring are distributed more evenly over the circumference of the piston and the axial unit, thereby preventing skewing. Each guideway segment then extends identically to the adjacent guideway segment, but is offset at an angle.

[0014] The use of three guide pins is considered particularly advantageous, so that the link is divided into three identical link sections and each point of a link section is repeated after a rotation of 120°. Accordingly, the guide pins are also offset by 120° relative to each other in this case.

[0015] In order to place the axial unit itself in a rotational movement about the longitudinal axis, it can be provided that the axial unit cooperates with a toothed ring surrounding the axial unit. The toothed ring can in particular tightly surround the axial unit so that the forces acting on the toothed ring are transmitted to the axial unit. In a simple first design, this can be done directly when the toothed ring is connected to the axial unit without play. Thus, any force introduced into the toothed ring is directly transmitted to the axial unit. However, this has the disadvantage that, for example, when a drive module is used in a force tensioner, it is not possible to build up a tensioning force without further supplying the force tensioner. Therefore, it is preferred that the toothed ring is movably but elastically supported on the axial unit about a center position. If the force tensioner reaches a stop position in the above case (for example, due to the gripping of a workpiece), further force can be provided to the toothed ring, which is introduced into the elastic part of the toothed ring relative to the axial unit. Therefore, when the workpiece is loaded with force, the force tensioner is tensioned again by the elastic force, without the toothed ring having to be mechanically activated again for this purpose. The system tensions itself when necessary, so that the workpiece is always reliably held.

[0016] In a specific design of the support of the toothed ring, at least two support sleeves can be provided at the axial unit, and a radial guide can be formed between the support sleeve and the toothed ring, wherein the guide key is guided in the guide groove. Thus, when the toothed ring moves relative to the axial unit, the toothed ring is guided in a non-lost manner. It is possible for the groove to be formed in the toothed ring and in the axial unit. However, since the axial unit always includes two cam disks and is thus constructed in multiple layers, it is preferred that the support sleeve forms the guide groove and is part of the axial unit.

[0017] The guide groove can also have a groove-shaped widening, wherein a driver for force transmission is accommodated in the groove-shaped widening. If the guide groove is in turn associated with the axial unit, this means that the driver is fixedly connected to the toothed ring and is formed integrally with the toothed ring as required. The driver is located in the widening of the groove and can furthermore advantageously be supported on both sides with respect to the end-side ends of the groove-shaped widening by means of compression springs. These compression springs absorb further energy after reaching the contact position of the force tensioner, which is connected to the piston, for example, in order to re-tension the force tensioner relative to the workpiece.

[0018] To drive the ring gear, the drive module can be equipped with an electric motor in the housing, which directly or indirectly cooperates with the ring gear with a transmission interposed therebetween. Particularly advantageously, the electric motor can be directly equipped with a planetary gear, thereby enabling the transmission of high torques. The torque can then be transmitted to the ring gear by means of a spur gear transmission.

[0019] Furthermore, it can be provided that the electric motor is assigned a microcontroller which is data-connected to the force sensor for force control. In such a solution, the sensor detects the force actually applied by the force tensioner and adjusts the control of the electric motor accordingly.

[0020] Finally, to prevent unintentional movement of the ring gear after the electric motor is switched off, the ring gear can be assigned a holding brake, preferably an electric holding brake without current locking. This holding brake can also cooperate with the ring gear via the above-mentioned spur gear transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention described above is explained in more detail below based on examples.

[0022] in:

[0023] Figure 1 The electromechanical drive module is shown in a perspective view from obliquely above.

[0024] Figure 2 The perspective partial section shows the Figure 1 The driver module,

[0025] Figure 3 The side section shows the Figure 2 The piston of the drive module together with the axial module and the ring gear,

[0026] Figure 4 The perspective partial section shows the Figure 3 The piston of the cam disk with axial module together with the support sleeve and the ring gear, and

[0027] Figure 5 The complete axial module with the ring gear and the piston is shown in a perspective view obliquely from above. DETAILED DESCRIPTION

[0028] Figure 1A drive module 1 is shown which is designed as a purely electromechanical alternative to a hydraulic piston. To this end, the drive module 1 has a piston 21 which is accommodated centrally in the housing 2 of the drive module 1 and can be moved purely electromechanically out of the housing 2 and into the housing 2 along the longitudinal axis 6. The drive module 1 is functionally designed in such a way that it also meets all the requirements imposed on a hydraulic piston. In this way, the drive module can be connected to the machine spindle via the screw 3 in order to be held thereon. The centering edge 4 ensures planar contact with respect to the tensioning device to be connected, and the tensioning device itself can be connected to the piston 21 via the piston coupling 22, so that the tensioning device can be subjected to compressive and tensile forces. It is only necessary to provide the required electrical energy in addition, which can be introduced via the machine spindle.

[0029] Figure 2 The structure of the housing is shown, wherein the arrangement is designed to be circularly symmetrical. The components arranged around the piston 21 and the axial unit 8 surrounding the piston 21 are used three times, but this can be scaled to a certain extent. Instead of three electric motors 15 with a transmission 16 and a holding brake 17, fewer or more can also be used, on the one hand to increase the force on the axial unit and on the other hand to ensure a uniform coupling of forces and avoid the occurrence of torsional forces.

[0030] The piston 21 is supported in the interior of the housing 2 in such a way that it is held in the housing in a rotationally fixed but longitudinally movable manner. This arrangement is suitable for piston strokes of up to 6 mm. To achieve this stroke, the electric motor 15 acts on a toothed ring 18 with a transmission 16 interposed therebetween, which surrounds the axial unit 8 which is movable radially but fixed in the longitudinal direction 6. The holding brake 17 can be used to prevent the toothed ring 18 from rotating again in the opposite direction due to the restoring force after the rotation of the electric motor 15 has ended. The piston 21 is supported in a dust-proof and dirt-proof manner by means of the seal 5.

[0031] If the ring gear 18 is finally rotated by means of the electric motor 15 , this rotation is transmitted to the axial unit 8 . Figure 3Here, it is shown that the piston stroke is generated due to the rotation of the axial unit 8. The substantially cylindrical piston 21 has a plurality of guide pins 23 on its circumference, to which a sliding bearing 24 is respectively inserted for better support. The cam disks 9 of the axial unit 8 are annular disks connected to each other, which have mutually facing projections at their inner edges, which form corresponding control cams. The cam disks 9 thus jointly form a guideway 10, which is inclined relative to the longitudinal axis 6. This guideway is repeated for each guide pin 23 of the piston 21, and therefore is repeated three times with an offset of 120° in the arrangement of three guide pins 23. By means of the anti-rotation device 25 that ensures that the piston cannot rotate together with the housing 2, the guide pin 23 must move in the guideway 10 due to the rotation of the axial unit 8 in the rotation direction 7, and has a movement portion in the longitudinal direction 6, which causes the piston stroke. The anti-rotation device is realized as a groove having a corresponding counterpart on the housing 2 , wherein the groove and counterpart are connected via a key in such a way that the piston is supported in a rotationally fixed manner but in a longitudinally displaceable manner.

[0032] exist Figure 4 2 shows how the cam disks 9 of the axial unit 8 arranged around the piston 21 are joined together. This is achieved by means of two support sleeves 11, which are screwed to the cam disk 9. The support sleeves 11 here open guide grooves 12, in which corresponding guide keys 19 of the toothed ring 18 are guided radially displaceably. The toothed ring 18 is thus movable relative to the axial unit 8, but has a driver 20, which is arranged on the inner side of the toothed ring 18 every 120° in this case in order to surround the guide keys 19.

[0033] exist Figure 5 In the drawing, the driver 20 with the toothed ring 18 fixed thereto is again shown together with the complete axial unit 8 and the piston 21. The driver 20 is located in the widening 13 of the guide groove 12, which is also provided every 120°. Compression springs 14 are arranged on both sides of the driver 20, by means of which the driver 20 is supported at its end-side ends relative to the groove-shaped widening 13, so that additional tensioning is established when the toothed ring 18 is further rotated after the tensioning means, which may be connected to the piston 21, has come into contact and after the stop of the piston 21 which is present in this regard. If, for example, the grip of the tensioning means is loosened due to mechanical processing of the workpiece, re-tensioning is carried out by the force stored in the compression spring 14 and no additional activation of the electric motor 15 is required for re-tensioning, while the workpiece is securely held.

[0034] Above, therefore, a drive module is described which overcomes the known disadvantages of the prior art and constitutes an equivalent alternative to known hydraulic pistons.

[0035] Reference numerals list

[0036] 1. Driver module

[0037] 2 Shell

[0038] 3. Screw-on

[0039] 4 Centering edge

[0040] 5 Seals

[0041] 6 Longitudinal axis

[0042] 7Rotation direction

[0043] 8 axial units

[0044] 9 Cam disc

[0045] 10 chute

[0046] 11 Support sleeve

[0047] 12 Guide slots

[0048] 13 Widening

[0049] 14Compression spring

[0050] 15 Electric Motor

[0051] 16 Transmission

[0052] 17 Holding brake

[0053] 18 gear ring

[0054] 19 Boot Keys

[0055] 20 driving parts

[0056] 21 Piston

[0057] 22 Piston connector

[0058] 23 guide pins

[0059] 24 Sliding bearings

[0060] 25 Anti-rotation device

Claims

1. A drive module comprising a housing (2) and a piston (21) which is mounted in a rotationally fixed manner in relation to the housing (2) in the direction of a longitudinal axis (6) but is longitudinally displaceable, the piston being used for pressure or tension actuation, in particular for a tensioning device, It is characterized in that The piston (21) is surrounded by an axial unit (8) which is mounted rotatably but immovably in the direction of the longitudinal axis (6), wherein the axial unit (8) is electrically actuated in the direction of rotation (7) and a guide groove (10) is formed between the piston (21) and the axial unit (8), in which at least one guide pin (23) is guided along a control cam inclined in the direction of the longitudinal axis (6) in order to generate a piston stroke.

2. The driving module according to claim 1, characterized in that: The axial unit (8) has two cam disks (9) which jointly form the link (10), wherein the cam disks (9) are connected to one another in a rotationally fixed manner with at least one supporting sleeve (11) interposed therebetween.

3. The driving module according to claim 1 or 2, characterized in that: The slotted link (10) is divided into a plurality of slotted link sections of the same type, and a guide pin (23) is guided in each slotted link section.

4. The driving module according to claim 3, characterized in that: Three slotted guide sections and three guide pins (23) are respectively arranged at intervals of 120°.

5. The driving module according to any one of claims 2 to 4, characterized in that: The axial unit (8) interacts with a toothed ring (18) surrounding the axial unit.

6. The driving module according to claim 5, characterized in that: The toothed ring (18) is mounted on the axial unit (8) so that it can move, but is elastic about a center position.

7. The driving module according to any one of claims 2 to 6, characterized in that: At least two support sleeves (11) are provided, and a radial guide is formed between the support sleeves (11) and the toothed ring (18), wherein a guide key (19) is guided in a guide groove (12).

8. The driving module according to claim 7, characterized in that: The guide groove has at least one groove-shaped widened portion (13), wherein a driver (20) for force transmission is accommodated in the groove-shaped widened portion (13).

9. The driving module according to claim 8, characterized in that: The driver (20) is supported on both sides relative to the end faces of the groove-shaped widened portion (13) by means of compression springs (14).

10. A drive module according to any one of the preceding claims, characterized in that An electric motor (15) is associated with the housing (2) and interacts directly or indirectly with the ring gear with a transmission (16) interposed therebetween.

11. The driving module according to claim 10, characterized in that: The electric motor (15) is associated with a planetary gear transmission and / or a spur gear transmission.

12. The driving module according to any one of claims 10 or 11, characterized in that: The electric motor (15) is assigned a microcontroller for force control which is data-connected to a force sensor.

13. A drive module according to any one of the preceding claims, characterized in that A holding brake (17), preferably a non-current-locking electric holding brake (17), is associated with the ring gear (18).

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