Pivot drive

Abstract

A pivot drive device (1) having a base (10), an output element (12), and a rotary actuator (30) and two or more pivot actuators (42, 44), the output element being mounted to the base (10) in a manner rotatable about a rotation axis and pivotable about two or more pivot axes, the two or more pivot axes intersecting each other at intersections arranged on the rotation axis, the rotary actuator (30) and the pivot actuators (42, 44) being mounted in a manner fixed relative to the base (10).

Description

Technical Field

[0001] This invention relates to a pivot drive device. Background Technology

[0002] A pivot drive is an electromechanical device that allows controlled movement of an output element relative to a reference element (e.g., a base). Preferably, the output element can move about all three axes of a Cartesian coordinate system.

[0003] Pivot drives can be used in many applications. One example is a gripper that is attached to an output element and can be displaced relative to the base of the pivot drive. The base of the pivot drive can then be attached to the robot's arm.

[0004] An example of a prior art pivot drive is known from US 4399718. A disadvantage of this known pivot drive is that displacement about one axis causes translational displacement about another axis, potentially displacing the output element about that other axis. This complicates the displacement of the output element relative to the base. Summary of the Invention

[0005] The object of the present invention is to provide a pivot drive device in which controlled movement of the output element relative to the base is possible.

[0006] To achieve this objective, the present invention provides a pivoting drive device having a base, an output element, and a rotary actuator and two or more pivoting actuators. The output element is mounted to the base in a manner capable of rotating about a rotation axis and pivoting about two or more axes, the pivoting axes intersecting each other at intersections on the rotation axes. The rotary actuators and pivoting actuators are mounted fixed relative to the base. Arranging the pivoting axes such that they intersect each other at intersections on the rotation axes ensures that displacement about one axis does not cause translational displacement of the other axis. Ensuring that all axes intersect at a single point significantly simplifies the control of the output element's displacement. Furthermore, arranging all actuators fixed relative to the base ensures that during displacement of the output element relative to the base, none of the motors used in the actuators shift relative to the base, thus preventing bending loads from acting on cables or conductors if the motors shift relative to the base.

[0007] One type of displacement of the output element is rotation about the axis of rotation, also known as yaw displacement. To achieve this movement, the output element can be mounted to the drive element in a manner that allows it to pivot relative to the drive element but not rotate it.

[0008] The drive element can be rotatably mounted relative to the base, particularly via crossed roller bearings. The bearings provide smooth, low-friction, and precise movement of the drive element relative to the base. In the case of crossed roller bearings, the load acting on the output element can be reliably transmitted to the base.

[0009] As an alternative to crossed roller bearings, sliding bearings or simple roller bearings can be used.

[0010] A rotary actuator can be connected to a drive element via a gear arranged in the drive path between the rotary motor and the drive element. The gear allows for an increase in the torque provided by the rotary motor, thus allowing the use of a compact rotary motor.

[0011] Depending on the requirements, the gear can be self-locking or non-locking. For self-locking gears, worm gears are particularly suitable.

[0012] According to one embodiment, the output element is mounted to the drive element via a universal joint or universal connector. This connector provides torque transmission between the drive element and the output element while allowing pivoting movement of the output element relative to the base.

[0013] As an alternative to universal joints or universal couplings, constant velocity couplings can be used.

[0014] According to one embodiment, a pivot ring is mounted to the output element so that it can rotate relative to the output element about an axis coinciding with the axis of rotation of the output element. The pivot ring allows engagement at the output element to pivot the output element about the pivot axis in a mechanically very simple manner.

[0015] To move the pivot ring relative to the base, the pivot actuator engages at the pivot ring, specifically at an angle of 90° relative to each other. The combined action of the pivot actuators allows the pivot ring, and therefore the output element, to shift in all directions.

[0016] To enable the pivot ring to shift, each pivot actuator is operatively connected to an engagement element for engagement at the pivot ring, the engagement element being able to shift in a translational manner. This makes the structure of the pivot gear mechanically simple.

[0017] According to one embodiment, each pivot actuator is operatively connected to a gear for converting the rotational motion of the pivot motor into the translational motion of the engaging element. This gear allows for high actuation force to be introduced into the pivot ring while using a compact motor.

[0018] Depending on the requirements, the pivot gear can be a self-locking gear, especially a spindle drive or a non-locking gear.

[0019] To transmit the motion of the pivot gear to the pivot ring, the engaging element of the pivot gear is either a claw element or a ball element. This mechanically simple structure allows for reliable transmission of the motion of the engaging element to the pivot ring, while also allowing for compensation of the motion of the claw element and the ball element relative to each other.

[0020] The pivot ring is preferably held non-rotatably relative to the base in order to improve the positional accuracy of the pivot gear.

[0021] Preferably, the pivot ring includes an abutment element engaged between two or more guide surfaces, which are provided by the outer surface of the spindle drive. In this way, a particularly compact structure is achieved, which eliminates the need for space for separate guides.

[0022] The spindle of the pivot gear can extend perpendicularly to the extension plane of the base, resulting in a space-saving construction.

[0023] The rotation axes of the motor can be arranged such that they are parallel to the central axis of the spindle drive, and thus arranged on top of the base to accommodate the motor adjacent to the spindle drive, thereby achieving a compact design.

[0024] In an alternative, the motor can be housed in the base of the pivot drive. Attached Figure Description

[0025] The invention will now be described with reference to two embodiments shown in the accompanying drawings. In the drawings,

[0026] Figure 1 A first perspective view of the pivot drive device according to the first embodiment is shown;

[0027] Figure 2 It shows Figure 1 Second perspective view of the pivot drive mechanism in the middle;

[0028] Figure 3 It shows Figure 1 A side view of the pivot drive mechanism, in which the output elements are shown in different positions;

[0029] Figure 4 A front view of the pivot drive device of the first embodiment is shown, wherein the output element is shown in different displacement positions;

[0030] Figure 5 It shows Figure 4 A pivot drive mechanism in which the output element is not positioned at the center;

[0031] Figure 6 A top view shows the pivot drive device according to the first embodiment;

[0032] Figure 7 The pivot drive device according to the first embodiment is shown in an exploded view;

[0033] Figure 8 The rear view shows the pivot drive device according to the first embodiment;

[0034] Figure 9 It shows along Figure 8 The cross section of the IX-IX line in the diagram;

[0035] Figure 10 It shows along Figure 9 The cross-section of the XX line in the image;

[0036] Figure 11 A partial perspective sectional view of the pivot drive device according to the first embodiment is shown;

[0037] Figure 12 A partial top sectional view of the pivot drive device according to the first embodiment is shown;

[0038] Figure 13 A perspective view of the pivot drive device according to the first embodiment is shown, wherein the cover is removed;

[0039] Figure 14 Shown in different perspectives Figure 13 The pivot drive mechanism in the middle;

[0040] Figure 15 Shown at magnified scale Figure 14 Details in XV;

[0041] Figure 16 A bottom perspective view of the pivot drive device according to the first embodiment is shown;

[0042] Figure 17 A first perspective view of a pivot drive device according to a second embodiment of the present invention is shown;

[0043] Figure 18 A second perspective view of the pivot drive device according to the second embodiment is shown;

[0044] Figure 19 A partial bottom sectional view of the pivot drive device according to the second embodiment is shown;

[0045] Figure 20 A front view of the pivot drive device according to the second embodiment is shown;

[0046] Figure 21 It shows along Figure 20 The cross section of the XXI-XXI line; and

[0047] Figure 22 A bottom perspective view of the pivot drive device according to the second embodiment is shown. Detailed Implementation

[0048] The first embodiment of the pivot drive device 1 is in Figures 1 to 16 As shown in the image.

[0049] Generally, the pivot drive 1 is used to displace the output element 12 relative to the base 10 of the pivot drive 1. The output element 12 can be displaced about the three axes of a Cartesian coordinate system (see [link to Cartesian coordinate system]). Figure 2 The motions are, in other words, rolling about axis X, pitching about axis Y, and yaw about axis Z. The motion about axis Z is referred to as rotation below, while the motions about axes X and Y are referred to as pivoting below.

[0050] The base 10 can be installed in a fixed manner. Alternatively, the base 10 itself can be arranged in a movable manner, for example, by mounting it to the end of a robot arm.

[0051] Output element 12 is used to receive an element displaced by pivot drive 1. In a first embodiment, mounting bracket 2 is shown connected to output element 12. It can receive, for example, a mechanically actuated gripper.

[0052] For example, the rotation range here can be ±91° (see [link]). Figure 6 The range of pivoting movement can be ±23° (see [link to relevant documentation]). Figure 3 and Figure 4 ).

[0053] The output element 12 is supported on the drive element 14, which in turn is supported on the base 10, so that it can rotate relative to the base 10.

[0054] To rotatably mount the drive element 14 onto the base 10, a roller bearing 16 (shown schematically only here) is used. The outer ring of the bearing 16 (here by screw 18; see specifically) Figure 9 The bearing 16 is connected to the base 10, while the inner ring of the bearing 16 is connected to the drive element 14. Screws can also be used here again.

[0055] Roller bearing 16 is preferably a crossed roller bearing.

[0056] As an alternative to crossed roller bearings, simple roller bearings can be used. Sliding bearings can also be used.

[0057] Regardless of the specific type of bearing used, bearing 16 is adapted to precisely guide drive element 14 relative to base 10 while supporting loads acting on output element 12.

[0058] The output element 12 is connected to the drive element 14 in a manner that allows the output element 12 to pivot relative to the drive element 14, while also being connected to the drive element 14 in a non-rotatable manner.

[0059] In this embodiment, the universal joint or universal connector 20 is used to connect the output element 12 to the drive element 14.

[0060] Universal joint 20 here includes universal joint ring 22, which is connected to drive head 24 of drive element 14 by pin 26, pin 26 extending through drive head 24 and oriented perpendicularly to the axis of rotation of drive element 14.

[0061] As an alternative to a single pin 26, two shorter pins arranged on a common axis and protruding from opposite sides of the drive head 24 can be used.

[0062] A second set of pins 28 having a common axis is arranged at a 90° angle relative to the first pin 26, wherein the second pin 28 connects the universal joint ring 22 to the output element 12.

[0063] As an alternative to the universal joint 20, a constant velocity joint can be used to connect the output element 12 to the drive element 14 in a torque-transmitting but pivotal manner.

[0064] A rotary actuator is provided for rotating the drive element 14 relative to the base 10 and thus rotating the output element 12.

[0065] The rotary actuator includes an electric motor 30, preferably a stepper motor.

[0066] As an alternative to stepper motors, servo motors or similar motors can be used.

[0067] Rotary actuator 30 is connected to drive element 14 via gear 32 (see in detail) Figure 16 Gear 32 here includes a worm gear 34 driven by a rotary actuator 30, and a gear 36 meshing into the worm gear 34 and non-rotatably connected to the drive element 14.

[0068] The gear 32 is formed in a self-locking manner, so that when the rotary actuator 30 is deactivated, no brake or similar device is needed to prevent the output element 12 from rotating under external load.

[0069] If the self-locking characteristic of the gear is not required, a different construction can be used to connect the rotary actuator 30 to the drive element 14.

[0070] exist Figure 16 In the image, a stop pin 38 can be seen, which engages with an arcuate portion provided in the gear 36. The stop pin 38 provides a mechanical end stop, which prevents the drive element 14 from rotating excessively relative to the base 10.

[0071] The worm gear 34 can be rotated mechanically without the use of the rotary actuator 30. For this purpose, a plug 40 is provided in the base 10, which, when removed, provides passage to the end face of the shaft on which the worm gear 34 is disposed. The shaft can be rotated by inserting a screwdriver, Allen wrench, or similar tool.

[0072] To enable the output element 12 to pivot relative to the drive element 14, at least two pivot actuators 42, 44 are provided. A stepper motor is preferred, similar to the rotary actuator 30. Alternatively, a servo motor or a similar drive can be used.

[0073] Generally, pivot actuators 42 and 44 act on a pivot ring 46, which is rotatably connected to the output element 12 relative to it. Preferably, a roller bearing 48 is used to mount the pivot ring 46 onto the output element 12. Thus, any pivoting motion introduced into the pivot ring 46 is transmitted to the output element 12.

[0074] The pivot ring 46 is provided with two actuating protrusions 50, which are arranged at a 90° angle relative to each other (see [link]). Figure 12 In the embodiment shown in the figure, the actuating protrusion 50 is a spherical element that is bolted to the pivot ring 46.

[0075] It is advantageous to arrange the actuating protrusions 50 at a 90° angle relative to each other because the resulting lever arm used to shift the pivot ring 46 is at its maximum. However, different angles may be used other than the arrangement in which the actuating protrusions 50 are arranged (almost) diametrically relative to each other.

[0076] At each actuating protrusion 50, an engaging element 52 engages, which is here formed as a claw (see in detail). Figure 7 and Figure 14 ).

[0077] The actuating protrusion 50 is formed as a partially spherical shape, which is engaged by at least two flat surfaces arranged opposite to and parallel to each other. This structure allows the actuating protrusion 50 to pivot relative to the claw, while also being able to translate relative to the claw.

[0078] Each engaging element 52 is connected to a nut 54 arranged on a spindle 56. Each spindle 56 is part of a spindle drive 58 or a pivot drive for displacing the engaging element 54 in a translational manner.

[0079] 56 per spindle (see also) Figure 10) is connected to its respective pivot actuators 42, 44 via gear 60 (see See Figure 16 ).

[0080] Each spindle drive 58 includes a housing 62, which prevents the nut 54 from rotating when the spindle 56 rotates.

[0081] The pivot ring 46 is non-rotatably held relative to the base 10, meaning it cannot rotate about the axis of rotation / central axis of the output element 12. In a simplified embodiment, this can be achieved by supporting any torque via the spindle drive 58, particularly through the engagement between the actuating protrusion 50 and the claw 52.

[0082] To achieve higher precision, the pivot ring 46 is provided with an adjacent element 64 that engages with the housing 62 of the spindle drive.

[0083] In a manner similar to that of the rotary drive, each spindle drive 58 is provided with an end cap 60, which, when removed, allows access to the end of the respective spindle, so that the spindle can be manually rotated without operating the pivot actuators 42, 44.

[0084] A housing 68 is provided to seal all components of the pivot drive 1 relative to the environment. A flexible seal 70 is arranged between the output element 12 and the edge of the housing 68 to prevent contaminants from entering the housing 68.

[0085] When the two engaging elements 52 are displaced in the same direction, the output element 10 pivots about the axis y. If one engaging element moves upward and the other moves downward, the pivoting motion about the axis y is performed. Proper control of the displacement of the engaging elements 52 allows the output element 10 to pivot in each direction.

[0086] Furthermore, the output element 12 can be rotated by operating the rotary actuator 30.

[0087] Any pivoting motion occurs about the intersecting axes of the output element 12 and the drive element 14 at the point of intersection. In other words, the intersection is located at the center of the universal joint that connects the drive element 14 to the output element 12.

[0088] As in Figure 10 As can be seen, the spindle drive is arranged such that the axis of rotation of the spindle 56 extends perpendicularly to the extending plane of the base 10. For example, particularly... Figure 9 As can be further seen, the rotation axis of the drive element 14 is also arranged perpendicularly to the extension plane of the base 10.

[0089] Actuators 30, 42, and 44 are arranged parallel to the spindle drive 58. Preferably, the rotation axis of the motor used in actuators 30, 42, and 44 is also arranged perpendicular to the extension plane of the base 10.

[0090] The drive electronics for controlling actuators 30, 42, and 44 are preferably integrated into the pivot drive unit 1. They may be arranged adjacent to actuators 30, 42, and 44 below the housing 68.

[0091] The second embodiment of the pivot drive device 1 is in Figures 17 to 22 The figures are shown in the figure. All elements known from the first embodiment are referred to using the same reference numerals and with reference to the above notes.

[0092] The difference between the first and second embodiments is that, in the second embodiment, the actuators 30, 42, and 44 are not arranged on the top of the base 10, on the side of the spindle drive 58 opposite to the output element 12, but are arranged inside the base 20. For this purpose, the height of the base 10 is increased to create the space required to accommodate the actuators 30, 42, and 44 (and possibly their associated drive electronics).

[0093] Due to the different positions of actuators 30, 42, and 44, base 10 now has a square shape instead of a rectangular shape.

Claims

1. A pivot drive (1) having a base (10), an output element (12) and having a rotary actuator (30) and two or more pivot actuators (42, 44), the output element being mounted to the base (10) in a manner rotatable about a rotary axis and pivotable about two or more pivot axes, the two or more pivot axes intersecting one another at a cross point arranged on the rotary axis, the rotary actuator (30) and the pivot actuators (42, 44) being mounted in a fixed manner relative to the base (10), wherein the output element (12) being mounted to a drive element (14) in a manner pivotable but not rotatable relative to the drive element (14), and the drive element (14) being rotatably mounted relative to the base (10) by a cross roller bearing (16).

2. The pivot drive (1) according to claim 1, wherein the rotary actuator (30) being connected to the drive element (14) by a first gear wheel (32) arranged in a drive path between a rotary motor and the drive element (14).

3. The pivot drive (1) according to claim 2, wherein the first gear wheel (32) is self-locking.

4. The pivot drive (1) according to claim 3, wherein the first gear wheel (32) is a worm wheel (34, 36).

5. The pivot drive (1) according to claim 2, wherein the first gear wheel is a non-locking gear wheel.

6. The pivot drive (1) according to claim 1, wherein the output element (12) is mounted to the drive element (14) by a gimbal (20) or cardan joint.

7. The pivot drive (1) according to claim 1, wherein a pivot ring (46) is mounted to the output element (12) so as to be rotatable relative to the output element (12) about an axis coinciding with the rotary axis of the output element (12).

8. The pivot drive (1) according to claim 7, wherein the pivot actuators (42, 44) engage at the pivot ring (46) at an angle of 90° relative to one another.

9. The pivot drive (1) according to claim 8, wherein each pivot actuator (42, 44) is operatively connected to an engagement element (52) for engaging at the pivot ring (46), the engagement element (52) being displaceable in a translatory manner.

10. The pivot drive (1) according to claim 9, wherein each pivot actuator (42, 44) is operatively connected to a second gear wheel (60) for converting a rotary motion of a pivot motor into a translatory motion of the engagement element (52).

11. The pivot drive (1) according to claim 10, wherein the second gear wheel (60) is a self-locking gear wheel.

12. The pivot drive (1) according to claim 11, wherein the second gear wheel (60) is a spindle drive (58).

13. The pivot drive (1) according to claim 11, wherein the second gear wheel (60) is a non-locking gear wheel.

14. The pivot drive (1) according to claim 9, wherein the engagement element (52) is one of a claw-shaped element and a ball-shaped element.

15. The pivot drive (1) according to any one of claims 7 to 14, wherein the pivot ring (46) is held non-rotatable relative to the base (10).

16. The pivot drive arrangement (1) according to claim 12, wherein the pivot ring (46) comprises an abutment element (64) engaging between two or more guide surfaces, the two guide surfaces being provided by an outer surface of the spindle drive (58).

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