Actuator for providing a torque, comprising a linear drive

Abstract

The invention relates to an actuator (1) for providing a torque, said actuator comprising a linear drive (2) and a gearbox (3) for converting a linear motion into a rotary motion, the gearbox (3) comprising a rod (4) which rotationally drives a shaft (5) to be subjected to a torque, the gearbox (3) further having a coupling element (6), the coupling element (6) is connected to the linear drive (2) via a first connection point (7) and to the rod (4) by means of a second connection point (8) such that energy is transmitted only via the coupling element (6) between the linear drive (2) and the rod (4), and the coupling element (6) is rotatably mounted at the two connection points (7, 8).

Description

Technical Field

[0001] The present invention relates to an actuator for providing torque, the actuator having a linear drive and a gear mechanism for converting linear motion into rotational motion, the gear mechanism including a lever that rotatably drives a shaft to which torque is applied. Background Technology

[0002] Such an actuator is known from DE 10 2016 207 827 A1, which has a nonlinear actuating force of an actuation unit used in an automatic transmission (preferably a PRND automatic transmission system) for motor vehicles. For this purpose, a corresponding sliding track is provided to generate nonlinearity.

[0003] An actuator is known from WO 2015 070 850 A1, which is preferably used for clutch actuation using a hinged transmission between a linear transmission and a shaft.

[0004] Generally, such actuators are known from DE 10 2018 116 133 A1. Summary of the Invention

[0005] The present invention aims to provide, in a simple manner, an actuator of the type discussed that has a nonlinear characteristic curve.

[0006] This objective of the invention is achieved by an actuator of the type discussed, having the features of claim 1.

[0007] According to the invention, the gear mechanism of the actuator further includes a coupling element connected to a linear drive via a first connection point and to a rod via a second connection point, such that energy is transferred between the linear drive and the rod only via the coupling element.

[0008] The connecting element is rotatably mounted at the two connection points.

[0009] In addition to the rod and linear actuator, the connecting element also provides a third component that connects the rod and linear actuator. This third component can be installed in a particularly simple manner and is capable of realizing the nonlinear characteristic curve of the actuator through the corresponding energy transfer from the linear actuator to the rod and thus to the shaft.

[0010] Furthermore, the rod is fixed to the shaft in rotation at the second rod end via a third connection point, and rotatably connected to the connecting element at the first rod end via a second connection point, with a rigid connection established between the two connection points. The nonlinearity of the actuator can be easily adjusted by changing the position of the connection points and the length of the connecting element, because the distance from the second rod end to the shaft can be kept constant, and only the transmitted torque or the corresponding rotational speed can be changed. In other words, the movement of the rod in space is limited by the fixed position of the housing at the third connection point, which acts as a constraint, and the rotational speed and torque of the shaft are determined by the length of the connecting element along with its position on the linear actuator.

[0011] Furthermore, according to the present invention, a rigid connection is established between the first connection point and the second connection point, such that the linear motion of the first connection point by the linear actuator causes a first pivoting motion of the second connection point about the first connection point, and causes a second pivoting motion of the second connection point about a third connection point, such that the rotation of the shaft is caused by the second pivoting motion due to the rotationally fixed connection between the rod and the shaft. The distance traveled by the second connection point is predetermined by the constraint of the rigid rod. By superimposing the two pivots onto a fixed predetermined curve, the nonlinearity of the rotational speed or the transmitted torque is correspondingly predetermined.

[0012] According to the invention, the connecting element connects the rod and the linear actuator to each other such that the second connection point moves along the trajectory, so that in a first working region around a first endpoint of the trajectory, the movement of the first connection point is progressively accelerated by the linear actuator into a first rotational motion of the shaft, and in a second working region around a second endpoint, the movement of the first connection point is progressively decelerated by the linear actuator into a second rotational motion of the shaft, the first rotational motion being transmitted with less force and covering a larger angular range than the second rotational motion over a time interval. In this way, specific operating points and intermediate transition regions for the actuation force of the shaft can be defined, corresponding to the desired nonlinearity of the actuation and transitioning between each other.

[0013] In a first alternative according to the invention, at the second end point, the connecting element is oriented perpendicular to the axis of motion of the rod and the linear actuator, and the rod is oriented parallel to the axis of motion. In this arrangement, force transmission is difficult. Therefore, the force acting on the connecting element from the linear actuator acts perpendicular to the tangent of the arc described by the end of the second rod, resulting in a very small transmitted torque, and thus enabling high rotational speeds. In this arrangement, the actuator is also self-locking. This is especially true when considering the friction points of the actuator.

[0014] In a second arrangement according to the invention, alternatively or additionally, at the first end point, the connecting element is parallel to the axis of motion of the linear actuator and perpendicular to the rod orientation. This results in maximum torque and minimum rotational speed. Therefore, the actuator position is also stable in this case.

[0015] In a further development of the invention, a first stop, preferably a housing-fixing stop, may be provided at the first end point for fixing the first end point, and / or a second stop, preferably a housing-fixing stop, may be provided at the second end point for fixing the second end point, and the end of the second rod is designed to cause the rod to strike against the first stop and / or the second stop. In this way, the two stable ends of the actuator can firmly resist vibrational movement and also remain resistant to vibration.

[0016] For example, a stop can be provided in the extension of the spindle of the linear drive on the actuator housing, and the stop can be configured as a stop for the rod in the opposite end position.

[0017] In particular, the first stop and / or the second stop can be integrally formed from the actuator housing.

[0018] The advantage of positioning the stop on the housing and limiting the linear adjustability within the linear actuator to the linear actuator itself is that, in a further improvement, the rotor bearing of the linear actuator is positioned between the linear actuator and the rod. Therefore, the cumulative coefficient of friction does not fluctuate as it would with a combination of only sliding friction points, which is primarily determined by the sliding friction coefficients within the linear actuator and the stop, and negligibly by the rolling friction coefficient of the rotor bearing. This allows for more precise definition of the required drive torque of the linear actuator, which is essential for ensuring robust support within the stop.

[0019] The process for securely supporting the actuator at its endpoints involves slowly / decelerating the linear drive to a stop region. This means, for example, that the spindle of the linear drive moves against one of the stops and / or the rod moves against another. As the process continues, the linear drive continues to move in the same direction, or the corresponding spindle continues to rotate even after reaching the stop, and the linear drive, spindle, or rod moves with a defined torque, which is certainly less than the maximum possible torque of the motor or electric motor driving the linear drive or spindle. This ensures that even if boundary conditions (fluctuations in lubrication, temperature, and power supply, etc.) have changed, the support can be safely released so that a return to normal operating conditions is possible.

[0020] In order to enable the actuator to move against the stop in a particularly controlled manner to adjust or calibrate it, according to a further improvement, the first stop and / or the second stop have a specific degree of softness, which enables the predetermined linear motion of the linear actuator to be achieved.

[0021] The required locking torque can also be predetermined to a reasonable value by means of the effective radius of the stop for the spindle or rod or its variation during the design period.

[0022] Since the stop does not require additional parts, but only the matching geometry of the actuator housing, the end stop can be fixed in a way that does not affect the cost.

[0023] Finally, the present invention relates to an actuator comprising a linear drive and a gear mechanism for converting linear motion into rotary motion. In principle, those skilled in the art are well aware of various types of linear drives based on different principles, whether mechanical or hydraulic. A linear drive can, for example, be formed by a ball screw drive or a planetary roller screw drive. The linear motion can be provided by a nut on a spindle or by the spindle itself. The rotary motion of the shaft is generated by a rod connected to the shaft in a manner fixed in rotation. A connecting element establishes a rigid connection between the rod of the linear drive and the linear motion element (nut or spindle, etc.). This means that the connection point of the connecting element on the linear drive moves linearly only along a straight path, and the connection point of the connecting element on the rod pivots only around the axis of the shaft along a circular path with a predetermined radius r, while the distance between the two connection points on the rod and the linear drive remains constant. In this way, a trajectory of the second connection point on the rod is achieved, which provides a faster angular velocity with lower torque in a first working region and a lower angular velocity with higher torque in a second working region to drive the shaft. A corresponding transition region exists between the two working regions.

[0024] In this way, the shaft can provide rotational motion with a variable characteristic curve, i.e., a greater angular velocity in a first angular range than in a second angular range, and a correspondingly smaller torque in the first angular range than in the second angular range. This rotational motion can be used to actuate disconnection units, clutches, brakes, or parking locks in the drivetrain of motor vehicles or commercial vehicles.

[0025] The toggle lever mechanism described herein creates a non-linear characteristic curve between the linear advance of the linear actuator (e.g., spindle travel and lever rotation) or the driving force of the linear actuator or the spindle force and lever torque. Therefore, this actuator is particularly suitable for actuating loads that also have a non-linear actuation force characteristic curve. An example of this is the actuation of a parking lock.

[0026] This arrangement allows the shaft used for actuation loads to be positioned very close to the linear actuator—significantly closer to the linear actuator than in cases where only the actuating rod generates a relatively large actuation torque. Attached Figure Description

[0027] Exemplary embodiments of the invention are illustrated in the following figures. The invention is not limited to these exemplary embodiments, and other features according to the invention can be derived from these exemplary embodiments. In the figures:

[0028] Figure 1 The actuator according to the invention is shown in a partial cross-sectional view.

[0029] Figure 2 : This shows the symbolic representation of the trajectory of the rod for shaft actuation.

[0030] Figure 3 This illustrates an alternative arrangement of the connecting elements between the rod and the spindle.

[0031] Figure 4 It shows the results based on Figure 3 A diagram illustrating the torque generated by the actuator.

[0032] Figure 5 and Figure 6 The cross-sectional view shows the results based on... Figure 1 The actuator, wherein the rod is located at the first end point and the second end point,

[0033] Figure 7 This shows one half of the actuator housing. Detailed Implementation

[0034] Figure 1 An actuator 1 is shown for converting the linear motion of the linear drive 2 into the rotational motion 23, 24 of the shaft 5.

[0035] For this purpose, the linear drive 2 includes a spindle 50. The spindle 50 has an end cap 51, which is connected to the coupling element 6 on one side via a support roller 52. Instead of having only one support roller 52 on one side as shown here, the support rollers on both sides can also be connected to their respective coupling elements.

[0036] Support roller 52 represents the first connection point 7 for rotatably mounting the connecting element 6.

[0037] The connecting element 6 is designed as a linearly extending rigid metal plate component, which is connected to the spindle 50 at one end via a first connection point 7 and to the rod 4 at a second end via a second connection point 8. The connecting element 6 is also rotatably mounted on the rod 4 via the second connection point 8.

[0038] Rod 4 extends from its first rod end 9, which has a second connection point 8, to a third connection point 10 at its second rod end 11. Rod 4 is connected to shaft 5 at the third connection point 10 in a rotationally fixed manner. For this purpose, rod 4 has a bore 53 with an internal gear system 54. Shaft 5 has a corresponding external gear system 55, which engages in the internal gear system 54. Shaft 5 is rotatably mounted in actuator housing 40 and extends through actuator housing 40 along the direction of shaft axis 56. Shaft axis 56 extends perpendicular to both the motion axis 41 of main shaft 50 and the extension direction 57 of connecting element 6.

[0039] Outside the actuator housing 40, shaft 5 is connected to actuator element 60. Actuator element can be an eccentric disc, contour disc, or the like, and is configured to rotate by means of shaft 5. Parking locks, brakes, clutches, etc., can be actuated via actuator element 60.

[0040] The spindle 50, end cap 51, connecting element 6 and rod 4 are components of the gear device 3, which converts the linear motion of the spindle 50 of the linear drive 2 into the rotational motion 23, 24 of the shaft 5 to drive the actuator 60.

[0041] exist Figure 1 In position P1, the main shaft 50 is positioned such that the extension direction 57 of the connecting element 6 is substantially perpendicular to the axis of motion 41 of the main shaft 50 and the rod 4. In position P1, the main shaft 50 is practically fully extended, and the second connection point 8 is located at the second end point 22. If the main shaft 50 retracts, its corresponding travel path is connected via the connecting element 6 to the smaller travel path perpendicular to the second connection point 8. That is, in this case, the linear motion of the linear drive 2 is converted into a second rotational motion 24, transmitting maximum torque to the shaft 5 at minimum rotational speed.

[0042] exist Figure 2 The diagram shows the transmitted torque and associated rotational speed. The second connection point 8 is located at... Figure 2 At the second endpoint 22 in the left part, also as Figure 1 As shown, and located at the first end point 21 in the right-hand portion. At the second end point 22 of the second connection point 8, the first connection point 7 of the connecting element 6 is located on the motion axis 41 of the main shaft 50. The linear motion for retracting the main shaft 50 along direction 61 pulls the rod 4 into a second rotational motion 24 about the third connection point 10 via the second connection point 8. The second connection point 8 follows a trajectory 20, wherein the distance between the second connection point 8 and the third connection point 10 is r. This motion of the rod 4 is characterized by a minimum rotational speed and a maximum torque at the second end point 22.

[0043] exist Figure 2In the right-hand portion, the second connection point 8 is located at the first end point 21. In this case, the main shaft 50 is retracted so far that the rod element 4 is positioned virtually parallel to the main shaft 50 on the axis of motion 41. Then, extending the main shaft 50 results in the maximum rotational speed and minimum torque of the rod 4.

[0044] In the region between the two endpoints 21 and 22, lever 4 is therefore driven with a non-linear torque characteristic curve. Shaft 5 is driven accordingly, and the non-linear characteristic curve of shaft 5 can be used to actuate non-linear loads, such as parking locks.

[0045] Figure 3 An alternative arrangement of the connecting element 6 between the rod 4 and the spindle 50 is shown. In this case, the spindle 50 is in the retracted position P2, and the second connection point 8 is located at the second end point 22'. In the parallel position of the connecting element 6, the connecting element is positioned such that it covers the spindle 50 along the direction of the axis of motion 41. (The last sentence appears to be incomplete and possibly refers to a different arrangement.) Figure 1 and Figure 2 Compared to the previous implementation, the connecting element 6 is tilted at 90°.

[0046] It is possible Figure 4 Find the illustration of the torque generated by the actuator. In this case, the first endpoint 21' of the second connection point 8 is shown on the left, and the second endpoint 22' is shown accordingly on the right. Between the first and second endpoints, the second connection point 8 moves along trajectory 20'. Also in this case, the maximum torque is transmitted to the shaft 50 at the second endpoint 22' (right side), and the minimum torque is transmitted to the shaft at the first endpoint 21'. Therefore, the shaft 50 undergoes a first rotational movement 23' at the first endpoint 21' and a second rotational movement 24' at the second endpoint 22'. The lengths of the arrows for the rotational movements 23' and 24' represent the transmitted torque.

[0047] Figure 2 and Figure 4 The trajectories 20 and 20' of the two alternative schemes are actually mirror images and are otherwise indistinguishable. However, the direction of rotation under the minimum and maximum torque of shaft 5 is switched; that is, the rotational movements 23, 23' and 24, 24' are reversed and equal in magnitude in each case. Figure 2 In the first example, maximum torque is transmitted when the spindle 50 retracts, while according to Figure 4 In the second alternative, the maximum torque is transmitted when the spindle 50 is extended.

[0048] like Figure 3 As shown, according to Figure 1An alternative embodiment of the actuator 1 also includes a connecting element 6', which has two parallel partial connecting elements 6a located on both sides of the main shaft 50. Such a connecting element 6' can then also achieve... Figure 4 The motivation of alternative solutions in the process.

[0049] However, the same applies to the generation of the nonlinear characteristic curve for axis 5, such as... Figure 1 As already described in [the text].

[0050] Figure 5 and Figure 6 It shows that according to Figure 1 The actuator, shown in cross-section, is driven by a spindle driver, and stops 30 and 31 for the rod 4 and the spindle 50, respectively, are provided on the actuator housing 40.

[0051] exist Figure 5 In the middle, rod 4 or the second connection point 8 is located at the first end point 21, and... Figure 6 In the diagram, the second connection point 8 is shown as being located at the second endpoint 22. Figure 6 In the middle, when the spindle 50 retracts in the direction of the linear drive 2, the maximum torque is generated on the shaft 5.

[0052] exist Figure 5 In this configuration, rod 4 is positioned at its first end point 21 on the first stop 30. The first stop 30 is designed as an integral part of the actuator housing 40. If a predetermined torque is now applied by the spindle 50 or spindle drive 70, which presses rod 4 or the first rod end 9 against the first stop 30 with a predetermined stopping force, the position of rod 4 and thus the angular position of shaft 5 can be clearly set, and the actuator 1 can generally be fixed to prevent adjustments, for example, due to vibration.

[0053] exist Figure 6 In this configuration, rod 4 or the second connection point 8 is located at the second end point 22. The second stop 31 is now configured for the spindle 50 or the end cap 51 of the spindle 50. Similarly, the spindle 50 can now be pressed against the second stop 31 with a predetermined torque. Also in this configuration, the position of rod 4, and therefore the angular position of shaft 5, can be clearly defined, and actuator 1 can generally be fixed to prevent adjustments, for example, due to vibration.

[0054] Figure 5 and Figure 6The spindle 50 is further shown to be driven via a nut 71. The nut is connected to the spindle via a tooth tip 72. Since the spindle 50 is housed in the actuator housing 40 in a rotationally fixed manner, the rotational motion of the nut 71 is correspondingly converted into linear motion of the spindle 50. The spindle 50 is supported on the actuator housing 40 via the nut 71 and a rotor bearing 73. The nut 71 is driven via the rotor 74 of an electric motor 75.

[0055] As shown here, since the rotor bearing 73 is axially positioned between the stops 30, 31 and the rotor 74, the torque required to securely support the rod 4 or the spindle 50 at the first stop 30 or the second stop 31 can be set more precisely because the cumulative coefficient of friction does not fluctuate as it does with combinations of sliding friction points alone. The cumulative coefficient of friction is primarily determined by the sliding friction coefficient (spindle / nut, stop surface) and is negligibly determined only by the rolling friction coefficient of the rotor bearing.

[0056] Figure 7 Half of the actuator housing 40 is shown.

[0057] The actuator housing 40 has an inner contour 42. This contour 42 is embossed into the actuator housing 40 parallel to the main shaft 50 and serves to house a support element 43. The support element 43 is positioned at one end of the main shaft 50, such as... Figure 1 As shown, the main shaft 50 is supported on the actuator housing 40. Figure 1 As shown, the support element is preferably designed as a support roller 52. The support element 43 coincides with the first connection point 7. Preferably, the support element 43 includes two support rollers 52 arranged around the hinged first connection point 7 on both sides of the main shaft 50 and the connecting element 6, preferably located at the end of the main shaft 50, and the support rollers are supported on a corresponding frame-fixed support surface 44 of the contour 42 in the actuator housing 40 and can roll on the support surface. In this way, the efficiency of the actuator 1 can be improved (in principle, sliding bearings on one or both sides are also conceivable). The support surface 44 preferably extends parallel to the axis of motion 41 of the main shaft 50 or the linearly movable element of the linear actuator 2.

[0058] With the help of the actuator 1 shown here based on the principle of a toggle lever, a non-linear actuation characteristic curve can be easily achieved on the actuating element 60 via the linear drive 2. The provided stops 30, 31 can be used to prevent accidental adjustment due to vibration or similar reasons, and can also ensure the limited position of the actuator 1, for example, in the event of a power failure.

[0059] A safe actuation with good efficiency can be achieved by combining the support surface 44 with the support roller 52.

[0060] List of reference numerals

[0061] 1 Actuator

[0062] 2 Linear Drivers

[0063] 3. Gear assembly

[0064] 4 bars

[0065] 5-axis

[0066] 6, 6' connecting element

[0067] 6a Partial connecting elements

[0068] 7 First connection point

[0069] 8 Second connection point

[0070] 9. End of the first rod

[0071] 10 Third Connection Point

[0072] 11. End of the second rod

[0073] 20, 20' trajectory

[0074] 21, 21' First endpoint

[0075] 22, 22' Second endpoint

[0076] 23, 23' First rotational motion

[0077] 24, 24' Second rotational motion

[0078] 25 First pivotal motion

[0079] 26 Second pivotal motion

[0080] 30 First stop component

[0081] 31 Second stop

[0082] 40 Actuator housing

[0083] 41. Axis of Motion

[0084] 42 Outline

[0085] 43 Support elements

[0086] 44 Support surface

[0087] 50 spindle

[0088] 51 End Cap

[0089] 52 Support Rollers

[0090] 53 holes

[0091] 54 Internal Gear System

[0092] 55 External Tooth System

[0093] 56 axis lines

[0094] 57. Extension direction

[0095] 60 Actuating elements

[0096] 61 directions

[0097] 70 Spindle Driver

[0098] 71 Nuts

[0099] 72 tooth cusps

[0100] 73 Rotor bearings

[0101] 74 Rotors

[0102] 75 Electric Motor

[0103] P1, P2 spindle positions

Claims

1. An actuator (1) for providing torque, the actuator having a linear drive (2) and a gear mechanism (3) for converting linear motion into rotary motion, wherein, The gear mechanism (3) includes a rod (4) that rotatably drives a shaft (5) to which torque is applied. The gear mechanism (3) also has a connecting element (6) that is connected to the linear actuator (2) via a first connection point (7) and to the rod (4) via a second connection point (8), such that energy is transferred only between the linear actuator (2) and the rod (4) via the connecting element (6). The connecting element (6) is rotatably mounted at two connection points (7, 8). The rod (4) is fixed in rotation at the second rod end (11) via a third connection point (10) and rotatably connected to the connecting element (6) at the first rod end (9) via the second connection point (8). The rod (4) establishes a rigid connection between the two connection points (8, 10). The connecting element (6) establishes a rigid connection between the first connection point (7) and the second connection point (8), such that the linear movement of the first connection point (7) caused by the linear actuator (2) results in a first pivoting movement (25) of the second connection point (8) about the first connection point (7), and a second pivoting movement (26) of the second connection point (8) about the third connection point (10), such that the rotation of the shaft (5) is caused by the second pivoting movement (26) due to the rotationally fixed connection between the rod (4) and the shaft (5), and The connecting element (6) connects the rod (4) and the linear actuator (2) to each other such that the second connection point (8) moves along the trajectory (20, 20'), such that in a first working region around the first endpoint (21, 21') of the trajectory (20, 20'), the movement of the first connection point (7) is gradually accelerated by the linear actuator (2) into a first rotational motion (23, 23') of the shaft (5), and in a second working region around the second endpoint (22, 22'), the movement of the first connection point (7) is gradually decelerated by the linear actuator (2) into a second rotational motion (24, 24') of the shaft (5), the first rotational motion (23, 23') covering a larger angular range with less force than the second rotational motion (24, 24') over a time interval. The characteristic is that at the second end point (22, 22'), the connecting element (6) is oriented perpendicular to the rod (4) and perpendicular to the motion axis (41) of the linear actuator (2), and the rod (4) is oriented parallel to the motion axis (41), and / or at the first end point (21, 21'), the connecting element (6) is oriented parallel to the motion axis (41) of the linear actuator (2) and perpendicular to the rod (4).

2. The actuator (1) according to claim 1, characterized in that, A first stop (30) for fixing the first end point (21, 21') is provided at the first end point (21, 21'), preferably a housing-fixed first stop, and / or a second stop for fixing the second end point (22, 22') is provided at the second end point (22, 22'), preferably a housing-fixed second stop, and the first rod end (9) is designed to cause the rod (4) to impact against the first stop (30) and / or the second stop.

3. The actuator (1) according to claim 1 or 2, characterized in that, A second stop (31) is provided for fixing the second end point (22, 22'), preferably a housing-fixed stop, and the spindle (50) or the end cap (51) of the spindle (50) is designed to impact against the second stop (31).

4. The actuator (1) according to claim 2 or 3, characterized in that, The first stop (30) and / or the second stop (31) are integrally formed from the actuator housing (40).

5. The actuator (1) according to any one of claims 2 to 4, characterized in that, The first stop (30) and / or the second stop (31) have a specific degree of flexibility, which enables the linear actuator (2) to achieve a predetermined linear motion.

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