An actuator for providing torque, equipped with a linear drive system.

Abstract

The present invention relates to an actuator (1) for providing torque, the actuator comprising a linear drive unit (2) and a gearbox (3) for converting linear motion into rotational motion, the gearbox (3) comprising a lever (4) for rotationally driving a shaft (5) to which torque is to be applied, the gearbox (3) also comprising a coupling element (6), the coupling element (6) being connected to the linear drive unit (2) via a first connection point (7) and to the lever (4) at a second connection point (8), thereby energy being transmitted between the linear drive unit (2) and the lever (4) exclusively via the coupling element (6), the coupling element (6) being rotatably mounted at both connection points (7, 8).

Description

Technical Field

[0001] The present invention relates to an actuator for providing torque, comprising a linear drive and a transmission for converting linear movement into rotational movement, the transmission comprising a lever for rotationally driving a shaft to which torque is to be applied.

Background Art

[0002] Such an actuator is known from German Patent Application Publication No. 102016207827 as having a non-linear actuating force for an operating unit for an automatic transmission of a motor vehicle (preferably a PRND automatic transmission system). For this purpose, a corresponding slide track is provided to generate non-linearity.

[0003] Preferably, an actuator for clutch operation having an articulated transmission between a linear transmission and a shaft is known from International Publication No. 2015 / 070850.

[0004] Generally, such an actuator is known from German Patent Application Publication No. 102018116133.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem of the present invention is to simply provide an actuator of a type having a non-linear characteristic curve.

Means for Solving the Problems

[0006] This object of the present invention is achieved by an actuator of the type having the features of claim 1.

[0007] According to the present invention, the transmission of the actuator further has a coupling element. The coupling element is connected to the linear drive unit via a first connection point and to the lever via a second connection point, thereby transmitting energy exclusively between the linear drive unit and the lever via the coupling element. The connecting element is rotatably mounted at both connection points.

[0008] In addition to the lever and linear drive unit, the coupling element provides a third component that connects them, which can be mounted in a simple manner and enables the actuator's nonlinear characteristic curve through the corresponding energy transfer from the linear drive unit to the lever and, thereby, to the shaft.

[0009] Furthermore, the lever is connected at a second lever end to the shaft via a third connection point so as to be rotatably fixed, and at a first lever end to a coupling element via a second connection point, so that the lever establishes a rigid connection between the two connection points. By adapting the position of the connection points and the length of the coupling element, the nonlinearity of the actuator can be easily adapted, because what can be changed is not the distance of the second lever end from the shaft, but exclusively the transmitted torque or the corresponding rotational speed. In other words, the movement of the lever in space is defined by the housing-fixed position of the third connection point as a limit, and the rotational speed and torque of the shaft are determined by the length of the coupling element relative to its position on the linear drive unit.

[0010] Furthermore, according to the present invention, the coupling element establishes a rigid connection between the first connection point and the second connection point, thereby, the linear movement of the first connection point by the linear drive device results in a first pivotal movement of the second connection point around the first connection point, and a second pivotal movement of the second connection point around the third connection point, thereby causing the rotation of the shaft to be triggered by the second pivotal movement by the rotation-fixed connection of the lever to the shaft. The distance the second connection point moves is predetermined by the limitation of the rigid lever. By superimposing the two pivots onto a fixed, predetermined curve, the nonlinearity of the rotational speed or the transmitted torque is predetermined accordingly.

[0011] According to the present invention, the coupling element connects the lever and the linear drive unit to each other such that the second connection point moves along the track, thereby in a first functional region around the first end of the track, the movement of the first connection point is stepped up by the linear drive unit to a first rotational movement of the shaft, and in a second functional region around the second end, the movement of the first connection point is stepped down by the linear drive unit to a second rotational movement of the shaft, the first rotational movement covering a larger angular range with smaller force transmission over a time interval than the second rotational movement. In this way, specific operating points and intermediate transition regions for the shaft's operating force, which transition from one another to the other, can be defined to accommodate the desired nonlinearity of the operation.

[0012] In the first alternative embodiment according to the present invention, at the second end, the coupling element is oriented perpendicular to the moving axis of the lever and the linear drive, and the lever is oriented parallel to the moving axis. In such an arrangement, force transmission is difficult. Therefore, the force acting on the coupling element from the linear drive acts perpendicular to the tangent to the arc drawn by the second lever end, and the transmitted torque is very small, thereby enabling high rotational speeds to be achieved. In this arrangement, the actuator is also self-locking. This is even more true when the friction points of the actuator are taken into consideration.

[0013] In the second arrangement according to the present invention, alternatively or additionally, at the first end, the coupling element is oriented parallel to the moving axis of the linear drive and perpendicular to the lever. This results in maximum torque and minimum rotational speed. Thus, the position of the actuator is stable in this case as well.

[0014] In a further development of the present invention, a first, preferably housing-fixed stop is provided at the first end to fix the first end, and / or a second, preferably housing-fixed stop is provided at the second end to fix the second end, and the second lever end is configured such that the lever contacts the first and / or second stop. In this way, the two stable ends of the actuator can be reliably moved and held against vibration.

[0015] The stopper can be provided, for example, on an extension of the spindle of a linear drive device on the actuator housing, and at the opposite end position as a stopper for a lever.

[0016] Specifically, the first stop unit and / or the second stop unit can be integrally formed from the actuator housing.

[0017] Instead of limiting the linear adjustability of the linear drive within the linear drive mechanism, the advantage of positioning the stop in the housing is that, in further developments, the rotor bearing of the linear drive mechanism is positioned between the linear drive mechanism and the lever, thereby preventing the cumulative friction coefficient, which is primarily determined by the sliding friction coefficient within the linear drive mechanism and the stop, and only negligibly determined by the rolling friction coefficient of the rotor bearing, from fluctuating as much as with a combination of sliding friction points alone. This allows for a more precise determination of the required driving torque of the linear drive mechanism, which is necessary to ensure reliable reinforcement at the stop.

[0018] The process for ensuring the actuator is reinforced at its end consists of slowly / decelerating the linear drive unit to a stopping area. This means, for example, that the spindle of the linear drive unit is moved toward one stopping point and / or the lever is moved toward the other stopping point. As the process continues, the linear drive unit continues to move in the same direction, or the corresponding spindle continues to rotate after reaching the stopping point, and the linear drive unit, spindle, or lever moves with a specified torque that is reliably below the maximum possible torque of the motor or electric motor driving the linear drive unit or spindle. This ensures that the reinforcement can be safely released so that it can return to a normal operating state even if boundary conditions (variations such as lubrication, temperature, and power supply) change.

[0019] In order to allow movement relative to the stop in a particularly controlled manner for adjusting or calibrating the actuator, according to a further development, the first stop and / or second stop have a certain degree of softness so that predetermined linear movement of the linear drive device is possible.

[0020] The required locking torque can also be predetermined to a reasonable value by the effective radius of the stop section for the spindle or lever, or by variations thereof in the configuration.

[0021] Since no additional components are required for the stop mechanism, and only a suitable shape for the actuator housing is needed, the fixing of the end stop mechanism can be achieved with virtually no cost.

[0022] Finally, the present invention relates to an actuator comprising a linear drive and a transmission for converting linear motion into rotational motion. In principle, those skilled in the art are familiar with various types of linear drive systems based on different principles, whether mechanical or hydraulic. A linear drive system can be formed, for example, by a ball screw drive or a planetary roller screw drive. Linear motion can be provided by a nut on a spindle or by the spindle itself. Rotational motion of the shaft is generated by a lever connected to the shaft so as to be rotationally fixed. A coupling element establishes a rigid connection between the lever and the linear motion element of the linear drive (such as a nut or spindle). This means that the distance between the two connection points on the lever and the two connection points on the linear drive remains constant, while the connection points on the lever pivot exclusively along a linear path and the connection points on the lever pivot exclusively along a circular path with a predetermined radius r around the axis of the shaft. In this way, a trajectory of the second connection point on the lever is realized that provides a lower torque and faster angular velocity in the first functional region, and a higher torque and lower angular velocity in the second functional region, in order to drive the shaft. Between the two functional regions, there is a corresponding transition region.

[0023] In this way, the shaft can provide rotational motion with a variable characteristic curve, namely, the angular velocity is greater in a first angular range than in a second angular range, and the torque is correspondingly smaller in the first angular range than in the second angular range. This rotational motion can be used to actuate a disengagement unit, clutch, brake, or parking lock in the drivetrain of an automobile or commercial vehicle.

[0024] The toggle lever mechanism described herein creates a non-linear characteristic curve between the linear feed of a linear drive, for example, spindle movement, and the rotation of a lever or the driving force of the linear drive, or between the spindle force and the torque of the lever. Thereby, such an actuator is particularly suitable for actuating a load that also has a non-linear actuating force characteristic curve. This embodiment is the actuation of a parking lock.

[0025] This arrangement enables positioning a shaft for actuating a load very close to the linear drive - significantly closer than would be possible if a relatively large actuating torque were generated only by the actuating lever.

[0026] Exemplary embodiments of the present invention are shown in the following drawings, but the present invention is not limited thereto and may bring further features according to the present invention.

Brief Description of the Drawings

[0027] [Figure 1] It is a partial cross-sectional view of an actuator according to the present invention. [Figure 2] It is a diagram showing a symbolic representation of the trajectory of a lever for shaft actuation. [Figure 3] It is a diagram showing an alternative arrangement of a coupling element between a lever and a spindle. [Figure 4] It is a diagram showing an illustration of the torque generated by the actuator according to FIG. 3. [Figure 5] It is a cross-sectional view of the actuator of FIG. 1 having levers at the first end and the second end. [Figure 6] It is a cross-sectional view of the actuator of FIG. 1 having levers at the first end and the second end. [Figure 7] It is a diagram showing half of an actuator housing.

Embodiments for Carrying Out the Invention

[0028] Figure 1 shows the actuator 1 for converting the linear movement of the linear drive unit 2 into the rotational movement 23 and 24 of the shaft 5.

[0029] For this purpose, the linear drive unit 2 comprises a spindle 50. The spindle 50 has an end cap 51, which is connected to the coupling element 6 via a support roller 52 on one side. Instead of just one support roller 52 on one side as shown here, support rollers on both sides can each be connected to their respective coupling elements.

[0030] The support roller 52 represents a first connection point 7 for rotatably mounting the coupling element 6.

[0031] The coupling element 6 is configured as a linearly elongated, rigid sheet metal component, connected at one end to the spindle 50 via a first connection point 7, and at the second end to the lever 4 via a second connection point 8. The coupling element 6 is also rotatably mounted to the lever 4 via the second connection point 8.

[0032] Lever 4 extends from its first lever end 9, which has a second connection point 8, to a third connection point 10 at its second lever end 11. At the third connection point 10, lever 4 is connected to shaft 5 so as to be rotatably fixed. For this purpose, lever 4 has a bore 53 having an internal gear system 54. Shaft 5 has a corresponding external gear system 55 that engages with the internal gear system 54. Shaft 5 is rotatably mounted within actuator housing 40 and extends through actuator housing 40 in the direction of shaft axis 56, which extends perpendicular to both the moving axis 41 of spindle 50 and the extension direction 57 of coupling element 6.

[0033] Outside the actuator housing 40, the shaft 5 is connected to the actuation element 60. This can be an eccentric disc, a contoured disc, etc., set to rotate by the shaft 5. A parking lock, brake, clutch, etc., can be actuated via this actuation element 60.

[0034] The spindle 50, end cap 51, coupling element 6, and lever 4 are components of the transmission device 3, which converts the linear movement of the spindle 50 of the linear drive device 2 into the rotational movement 23, 24 of the shaft 5 for driving the actuation element 60.

[0035] In Figure 1, the spindle 50 is in position P1, so that the extension direction 57 of the coupling element 6 is substantially perpendicular to the movement axis 41 and lever 4 of the spindle 50. In position P1, the spindle 50 is substantially fully extended, and the second connection point 8 is located at the second end 22. When the spindle 50 retracts, the corresponding travel path of the spindle 50 is connected via the coupling element 6 to the smaller travel path of the second connection point 8, which is perpendicular to it. That is, in this case, the linear movement of the linear drive unit 2 is converted into a second rotational movement 24. The maximum torque is transmitted to the shaft 5 at the minimum rotational speed.

[0036] An example of the transmitted torque and associated rotational speed is shown in Figure 2. The second connection point 8 is located at the second end 22 in the left portion of Figure 2 and at the first end 21 in the right portion, as also shown in Figure 1. At the second end 22 of the second connection point 8, the first connection point 7 of the coupling element 6 is located on the moving axis 41 of the spindle 50. A linear movement to retract the spindle 50 in direction 61 pulls the lever 4 through the second connection point 8 into a second rotational movement 24 around the third connection point 10. The second connection point 8 follows a trajectory 20 with a distance r between the second connection point 8 and the third connection point 10. This movement of the lever 4 is characterized by a minimum rotational speed and a maximum torque at the second end 22.

[0037] In the right-hand portion of Figure 2, the second connection point 8 is located at the first end 21. In this case, the spindle 50 retracts until the lever element 4 is positioned substantially perfectly parallel to the spindle 50 on the moving axis 41. Extending the spindle 50 results in the maximum rotational speed and minimum torque of the lever 4.

[0038] In the region between the two ends 21 and 22, the lever 4 is driven, thereby exhibiting a nonlinear torque characteristic curve. The shaft 5 is driven accordingly, and the nonlinear characteristic curve of the shaft 5 can be used to actuate a nonlinear load, such as a parking lock.

[0039] Figure 3 shows an alternative arrangement of the coupling element 6 between the lever 4 and the spindle 50. In this case, the spindle 50 is in the retracted position P2, and the second connection point 8 is located at the second end 22'. In the parallel position of the coupling element 6, the coupling element 6 is positioned to cover the spindle 50 in the direction of the movement axis 41. In contrast to the embodiments shown in Figures 1 and 2, the coupling element 6 is inclined at 90°.

[0040] An example of the torque generated by this actuator can be seen in Figure 4. In this case, the first end 21' of the second connection point 8 is shown on the left, while the corresponding second end 22' is shown on the right. Meanwhile, the second connection point 8 moves along the trajectory 20'. In this case as well, the maximum torque is transmitted to the shaft 50 at the second end 22' (right side), and the minimum torque is transmitted to the shaft 50 at the first end 21'. Therefore, the shaft 50 receives a first rotational movement 23' at the first end 21' and a second rotational movement 24' at the second end 22'. The lengths of the arrows for rotational movements 23' and 24' represent the transmitted torque.

[0041] The trajectories 20 and 20' of the two alternative configurations in Figures 2 and 4 are substantially mirror images and otherwise identical. However, the rotational direction of the shaft 5 at minimum and maximum torque is reversed, i.e., the rotational movements 23, 23' and 24, 24' are reversed and are of equal magnitude in both cases. In the first embodiment of Figure 2, the maximum torque is transmitted when the spindle 50 is retracted, whereas in the second alternative configuration of Figure 4, the maximum torque is transmitted when the spindle 50 is extended.

[0042] An alternative embodiment of the actuator 1 shown in Figure 1 also has a coupling element 6' having two parallel partial coupling elements 6a on either side of the spindle 50, as shown in Figure 3. Such a coupling element 6' also enables operation in the alternative configuration shown in Figure 4.

[0043] However, in this case, as already shown in Figure 1, the same applies to the generation of the nonlinear characteristic curve of shaft 5.

[0044] Figures 5 and 6 show the actuator according to Figure 1, with a cross-sectional view showing the drive by the spindle drive device, and stop sections 30 and 31 for the lever 4 and spindle 50 respectively provided in the actuator housing 40.

[0045] In Figure 5, the lever 4 or second connection point 8 is located at the first end 21, while in Figure 6, the second connection point 8 is shown at the second end 22. In Figure 6, maximum torque is generated on the shaft 5 when the spindle 50 retracts in the direction of the linear drive unit 2.

[0046] In Figure 5, the lever 4 is positioned at the first end 21 on the first stop 30. The first stop 30 is configured as an integrated component of the actuator housing 40. Here, when a predetermined torque is applied by the spindle 50 or the spindle drive 70, and that torque presses the lever 4 or the first lever end 9 against the first stop 30 with a predetermined stopping force, the position of the lever 4, thereby the angular position of the shaft 5, can be clearly set, and the actuator 1 can be fixed in place, for example, against adjustments caused by vibration.

[0047] In Figure 6, the lever 4 or the second connection point 8 is located at the second end 22. The second stop 31 is provided for the spindle 50 or the end cap 51 of the spindle 50. Similarly, the spindle 50 can be pressed against the second stop 31 with a predetermined torque. In this case as well, the position of the lever 4, thereby the angular position of the shaft 5, can be clearly set, and the actuator 1 can generally be fixed against adjustments caused, for example, by vibration.

[0048] Figures 5 and 6 further illustrate that the spindle 50 is driven via a nut 71, which is connected to the spindle via a toothed point 72. Since the spindle 50 is received to be rotatably fixed within the actuator housing 40, the rotational movement of the nut 71 is converted accordingly into a linear movement of the spindle 50. The spindle 50 is supported in 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.

[0049] As shown here, the rotor bearing 73 is positioned axially between the stoppers 30, 31 and the rotor 74, which allows for a more precise setting of the torque required to ensure the lever 4 or spindle 50 at the first or second stoppers 30, 31. This is because the cumulative friction coefficient, which is determined primarily by the sliding friction coefficient (spindle / nut, stopper surface) and only negligibly by the rolling friction coefficient of the rotor bearing, does not fluctuate as much as the combination of sliding friction points alone.

[0050] Figure 7 shows half of the actuator housing 40.

[0051] The actuator housing 40 has an inner contour 42. This contour 42 is embossed into the actuator housing 40 parallel to the spindle 50 and functions to accommodate a bearing element 43. The bearing element 43 is positioned at one end of the spindle 50 and supports the spindle 50 on the actuator housing 40, as shown in Figure 1. As shown in Figure 1, it preferably consists of support rollers 52. The bearing element 43 coincides with a first connection point 7. Preferably, this bearing element 43 is positioned around the articulated first connection point 7 between the spindle 50 and the coupling element 6, preferably on both sides of the end of the spindle 50, and consists of two support rollers 52 that are supported on the corresponding frame-fixed support surfaces 44 of the contour 42 in the actuator housing 40 and can roll there. In this way, the efficiency of the actuator 1 can be improved (in principle, single-sided or double-sided sliding bearings are also conceivable). The support surface 44 preferably extends parallel to the movement axis 41 of the spindle 50 or the linearly displaceable element of the linear drive unit 2.

[0052] According to the toggle lever principle, the actuator 1 shown herein allows for the easy realization of a nonlinear operating characteristic curve on the actuating element 60 via the linear drive unit 2. The provided stop units 30 and 31 can be used to prevent unintended adjustments due to vibrations, etc., and can also ensure the specified position of the actuator 1 in the event of a power outage, for example.

[0053] Reliable operation with good efficiency can be achieved through the support surface 44 together with the support roller 52. [Explanation of Symbols]

[0054] 1 Actuator 2 Linear drive unit 3. Transmission device 4 Lever 5 shafts 6, 6' connecting element 6a partially connected element 7. First connection point 8. Second connection point 9. First lever end 10. Third connection point 11 Second lever end 20, 20' orbit 21, 21' First end 22, 22' Second end 23, 23' First rotational movement 24, 24' Second rotational movement 25 First pivot movement 26. Second pivot movement 30 First stopping section 31 Second stopping section 40 Actuator Housing 41 Movement axis 42 Outline 43 Bearing elements 44 Support surface 50 spindles 51 End caps 52 Support rollers 53 Hole 54 Internal tooth system 55 External tooth system 56 Shaft axis 57 Extension direction 60 Actuating elements 61 directions 70 Spindle drive unit 71 Nut 72 Toothed dots 73 Rotor bearing 74 rotors 75 Electric motor P1, P2 spindle positions

Claims

1. An actuator (1) for providing torque, comprising a linear drive device (2) and a transmission device (3) for converting linear motion into rotational motion, wherein the transmission device (3) includes a lever (4) for rotationally driving a shaft (5) to which the torque is to be applied, and the transmission device (3) further includes a coupling element (6), The coupling element (6) is connected to the linear drive unit (2) via a first connection point (7) and to the lever (4) via a second connection point (8), thereby transmitting energy exclusively between the linear drive unit (2) and the lever (4) via the coupling element (6). The connecting element (6) is rotatably mounted at both connection points (7, 8). The lever (4) is connected at a second lever end (11) to the shaft (5) via a third connection point (10) so as to be rotatably fixed, and at a first lever end (9) to the coupling element (6) via the second connection point (8), and the lever (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), thereby causing the linear movement of the first connection point (7) by the linear drive device (2) to result in a first pivotal movement (25) of the second connection point (8) around the first connection point (7), and a second pivotal movement (26) of the second connection point (8) around the third connection point (10), thereby causing the rotation of the shaft (5) to be triggered by the second pivotal movement (26) due to the rotationally fixed connection of the lever (4) to the shaft (5). The coupling element (6) connects the lever (4) and the linear drive unit (2) to each other such that the second connection point (8) moves along the track (20, 20'), thereby in a first functional region around the first end (21, 21') of the track (20, 20'), the movement of the first connection point (7) is stepped up by the linear drive unit (2) to a first rotational movement (23, 23') of the shaft (5), and in a second functional region around the second end (22, 22'), the movement of the first connection point (7) is stepped down by the linear drive unit (2) to a second rotational movement (24, 24') of the shaft (5), and the first An actuator (1) wherein the rotational movement (23, 23') covers a larger angular range with less force transmission over a time interval than the second rotational movement (24, 24'), characterized in that at the second end (22, 22'), the coupling element (6) is oriented perpendicular to the lever (4) and the movement axis (41) of the linear drive device (2), the lever (4) is oriented parallel to the movement axis (41), and / or at the first end (21, 21'), the coupling element (6) is oriented parallel to the movement axis (41) of the linear drive device (2) and perpendicular to the lever (4).

2. The actuator (1) according to claim 1, characterized in that a first, preferably, housing fixing stop portion (30) is provided at the first end portion (21, 21') for fixing the first end portion (21, 21') and / or a second, preferably, housing fixing stop portion is provided at the second end portion (22, 22') for fixing the second end portion (22, 22'), and the first lever end portion (9) is configured such that the lever (4) contacts the first stop portion and / or the second stop portion (30).

3. A second, preferably, housing fixing stopper (31) is provided for fixing the second end (22, 22'), and the spindle (50) or the end cap (51) of the spindle (50) is configured to contact the second stopper (31), characterized in that the actuator (1) according to claim 1 or 2.

4. The actuator (1) according to claim 2 or 3, characterized in that the first stop portion (30) and / or the second stop portion (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 portion (30) and / or the second stop portion (31) have a specific degree of softness, thereby enabling predetermined linear movement of the linear drive device (2).

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