Actor

Abstract

Actuator (10) with a stator (14) and an armature (16) forming an electromagnetic drive (18) for a switching element (20) of the actuator (10) extending in an axial direction (A), wherein the actuator (10) is configured to adjust the armature (16) in the axial direction (A) by means of the stator (14), and has at least one coupling device (40) by means of which the switching element (20) can be coupled to the armature (16), wherein in a coupled position of the coupling device (40), the switching element (20) is adjusted in the axial direction (A) together with the armature (16), and in a decoupled position of the coupling device (40), the switching element (20) is not adjusted in the axial direction (A) when the armature (16) is adjusted in the axial direction (A).

Description

[0001] The invention relates to an actuator with an electromagnetic drive. The actuator is particularly suitable for use in vehicle transmissions, for example to axially adjust a switching element.

[0002] Electromagnetic actuators operating on the reluctance principle are highly dependent on the existing magnetic air gap and its change over the switching travel of the armature. For this reason, the usable stroke or switching travel of the armature is limited. Furthermore, in a conventional solenoid, the switching force decreases exponentially with increasing air gap. Large switching travels combined with large switching forces are therefore mutually exclusive.

[0003] Electromagnetic linear actuators enable the achievement of large switching travels and actuation forces. This is achieved by distributing several coils along a direction of travel to generate a moving magnetic field. To generate high actuation forces, permanent magnets are often used on the push rod. The design, with multiple coils in series and the magnetic flux guided by the push rod, requires a significant amount of axial space. Due to their weight, cost, and the required installation space, such actuators are generally not suitable for use in gearboxes, where available space is extremely limited.

[0004] The object of the invention is to provide an actuator with an electromagnetic drive that is both compact and has large switching distances.

[0005] According to the invention, the actuator comprises a stator and an armature, which form an electromagnetic drive for an axially extending switching element of the actuator. The actuator is configured to adjust the armature axially by means of the stator and has at least one coupling device by means of which the switching element can be coupled to the armature. In a coupled position of the coupling device, the switching element is adjusted axially together with the armature, and in a decoupled position of the coupling device, the switching element is not adjusted axially when the armature is adjusted axially. The basic concept of the actuator according to the invention is to divide the total switching travel into several small individual strokes, so that a high actuating force is obtained for each stroke (due to the small air gap), while a large overall switching travel is achieved.At the same time, the Akor can be built compactly.

[0006] According to one embodiment, the coupling device is a coupling element with a coupling contour that, in the coupled position of the coupling device, engages with a radially opposite, complementary coupling contour of the switching element. During a switching stroke, the complementary coupling contours are engaged with each other, so that the resulting positive locking ensures that the forces between the armature and the switching element are reliably transmitted.

[0007] According to a further embodiment, the coupling contour of the coupling element and / or the coupling contour of the switching element is a toothed section, in particular with a sawtooth profile. The toothed section creates a ratchet effect, resulting in a defined, incremental movement in the desired direction. At the same time, it prevents the switching element from slipping back.

[0008] In one embodiment, the axial length of the coupling contour of the switching element is greater than the axial length of the coupling contour of the coupling element, so that the coupling element can interact with the coupling contour of the switching element over the entire switching path.

[0009] In another embodiment, the coupling element is radially pre-tensioned by a spring in the direction of the switching element, thus pre-tensioning the coupling device into the coupled position. The spring pre-tension ensures secure engagement of the coupling contours without additional actuating force.

[0010] According to one embodiment, the coupling device has at least one control element by means of which the coupling element can be adjusted between an activated state, in which the coupling device is adjustable between the decoupled and coupled positions, and a deactivated state, in which the coupling device cannot be adjusted to the coupled position. In this way, it is possible to reliably control which of the coupling devices is available for power transmission.

[0011] According to a further embodiment, the at least one control element is coupled to the coupling element via a control contour, in particular one that extends in the axial direction. The coupling element can be switched between the activated and deactivated states in a simple and compact manner by means of the control contour.

[0012] In one embodiment, the actuator is designed such that the coupling element is moved into the activated state when the at least one control element is pressed axially against a first axial stop of the actuator, and into the deactivated state when the at least one control element is pressed axially against a second axial stop of the actuator, which is arranged axially opposite to the first axial stop. This arrangement enables automatic switching of the coupling device by the armature movement itself.

[0013] In a further embodiment, the actuator has at least a second coupling device by means of which the switching element can be coupled to the armature, wherein in a coupled position of the second coupling device, the switching element is adjusted in the opposite direction to the axial direction together with the armature, and in a decoupled position of the second coupling device, the switching element is not adjusted in the opposite direction to the axial direction when the armature is adjusted in the opposite direction. With this design, the switching element can be adjusted bidirectionally by appropriately controlling the coupling devices.

[0014] According to one embodiment, the actuator has a first position sensor configured to determine the axial position of the armature relative to the stator, and a second position sensor configured to determine the axial position of the switching element relative to the stator. The position sensors allow the switching state to be monitored and the switching movements to be precisely tracked.

[0015] According to a further embodiment, the switching element has a shaft and a switching ring which is mounted on the shaft so as to be axially immovable and circumferentially rotatable, in particular wherein the switching ring is secured against rotation relative to the stator. This design allows relative rotation between the shaft and the actuator with simultaneous axial force transmission.

[0016] Further advantages and features will become apparent from the following description and the accompanying drawings. These show: - Fig. 1 in a sectional view an actuator according to the invention, - Fig. 2 in another section view the actuator from Fig. 1, - Fig. 3 in a side view first and second coupling devices of the actuator Fig. 1, - Fig. 4 in a sectional view the first and second coupling devices of the actuator. Fig. 1, - Fig. 5 in a sectional view a first coupling device made of Fig. 4 in a coupled position, - Fig. 6 in a sectional view a second coupling device made of Fig. 4 in a decoupled position, - Fig. 7 in a detailed view, section B from Fig. 3, and - Fig. Figure 8 shows a schematic representation of a method for axially adjusting a switching element of the actuator. Fig. 1.

[0017] Fig. Figure 1 shows a perspective view of an actuator 10 according to the invention, which for example forms an actuating device in a vehicle transmission.

[0018] The actuator 10 comprises a stator assembly 12 with a stator 14 and an armature 16 movable in axial direction A, which together form an electromagnetic drive 18 for a switching element 20 extending in axial direction A.

[0019] The stator assembly 12 is equipped with two coils 22 which are arranged within the stator assembly 12 for power generation and for guiding the magnetic flux.

[0020] The armature 16 is positioned below the stator assembly 12 and can move from a central position in and against the axial direction A.

[0021] To achieve high tightening forces with small air gaps, the armature 16 has conical surfaces 24 which interact with correspondingly complementary surfaces of the stator 14.

[0022] The stator assembly 12 is designed in such a way that a residual air gap is ensured between the armature 16 and the stator 14, which prevents the parts from magnetically sticking to each other.

[0023] As a magnetic barrier and to limit the armature stroke, two sliding rings 26 are arranged in the stator assembly 12, which consist of non-ferromagnetic material and guide the armature 16 over their radially inner sliding surface during the switching movement.

[0024] The switching element 20 comprises a shaft 28 and a switching ring 30, which is mounted on the shaft 28 so as to be immovable in the axial direction A and rotatable in the circumferential direction.

[0025] A coupling section 32 is arranged at an axial end of the switching element 20, by means of which the shaft 28 can be coupled to a complementarily designed coupling section in a torque-transmitting manner.

[0026] The switching ring 30 is coupled to the stator assembly 12 via cams / slots not shown, whereby the switching ring 30 is rotationally fixed to the stator assembly 12, while axial displacement is possible.

[0027] To facilitate manufacturing and assembly, the switching ring 30 can be segmented.

[0028] The shaft 28 is axially movable and rotatable relative to the armature 16 by means of bearing rings 33.

[0029] To determine the axial positions of the armature 16 and the switching element 20, first and second position sensors 34, 36 with an associated sensor board 38 are provided.

[0030] The first position sensors 34 are configured to detect the axial position of the armature 16, while the second position sensors 36 are configured to detect the axial position of the switching element 20.

[0031] Forces between the armature 16 and the switching element 20 are transmitted via first coupling devices 40 (see Fig. 2) and second coupling devices 42, which are arranged in a circumferential direction around the switching element 20.

[0032] In the present embodiment, the actuator 10 has three first coupling devices 40 (see Fig. 4), which are designed to adjust the switching element 20 in a switching direction in axial direction A, and three second coupling devices 42, which are designed to adjust the switching element 20 in a switching direction opposite to the axial direction A.

[0033] In principle, the actuator 10 can have any number of coupling devices 40, 42, but at least one first coupling device 40 or at least one second coupling device 42.

[0034] The coupling devices 40, 42 are arranged around the centrally arranged switching element 20 (see Fig. 3) with its switching ring 30 arranged in the circumferential direction.

[0035] Each of the coupling devices 40, 42 has a coupling element 44 which is guided radially movable in the armature 16.

[0036] The coupling elements 44 each have a coupling contour 46 (see Fig. 5 and Fig. 6) in the form of a toothing which can engage with a radially opposite, complementary coupling contour 48 of the switching ring 30.

[0037] In the illustrated embodiment, the teeth each have a sawtooth profile.

[0038] In this context, the coupling elements 44 of the first coupling devices 40 each have a toothing that is oriented opposite to the toothing of the coupling elements 44 of the second coupling devices 42 (see Fig. 5 and Fig. 6) The same applies analogously to the toothing of the respective complementary coupling contours 48 of the switching ring 30. In this way, the different switching directions in or against the axial direction A of the first and second coupling devices 40, 42 are realized.

[0039] As in Fig. As shown in Figure 3, the coupling contours 48 of the switching ring 30 each have an axial length L that is greater than the axial length l of the coupling contours 46 of the individual coupling elements 44.

[0040] The coupling devices 40, 42 are each connected between a coupled position (see Fig. 5) and a decoupled position (see Fig. 6) Adjustable.

[0041] In the coupled position, the coupling contour 46 of the coupling element 44 engages with the complementary coupling contour 48 of the switching ring 30, whereby the switching ring 30 is adjusted in the corresponding switching direction of the coupling device 40, 42 together with the armature 16.

[0042] In the decoupled position, the coupling contour 46 of the coupling element 44 and the complementary coupling contour 48 of the switching ring 30 are not engaged, so that the switching ring 30 is not adjusted in the corresponding switching direction of the coupling device 40, 42 when the armature 16 is adjusted.

[0043] Consequently, the coupling devices 40, 42 of the actuator 10 in the present embodiment are based on a positive locking (gearing) for power transmission.

[0044] In an alternative embodiment, power transmission through the coupling devices 40, 42 can be achieved by frictional engagement, for example in the form of a clamping connection.

[0045] The coupling elements 44 are each adjustable between an activated state, in which the corresponding coupling device 40, 42 is adjustable between the decoupled and coupled positions, and a deactivated state, in which the corresponding coupling device 40, 42 is locked in the decoupled position and therefore cannot be adjusted to the coupled position.

[0046] For controlling the first coupling devices 40, first control elements 50 are required (see Fig. 7) and for controlling the second coupling devices 42, second control elements 52 are provided, each in a corresponding receptacle 54 (see Fig. 2) are guided axially displaceably in the anchor 16.

[0047] In the present embodiment, each coupling device 40, 42 is assigned two control elements 50, 52.

[0048] Each control element 50, 52 has a control contour 56 extending in the axial direction A, which interacts with the associated coupling element 44.

[0049] In the deactivated state of the clutch element 44, the control element 50, 52 is in an axial position in which the control contour 56 pushes the clutch element 44 radially outwards to such an extent that its clutch contour 46 cannot engage in the complementary clutch contour 48 of the switching ring 30.

[0050] In the activated state of the clutch element 44, however, the control element 50, 52 is in an axial position in which the control contour 56 provides sufficient radial clearance for the clutch element 44, so that its clutch contour 46 can engage with the complementary clutch contour 48 of the switching ring 30.

[0051] When the first coupling devices 40 are in the coupled position (see Fig. 5) The switching ring 30 is moved in the switching direction of the first coupling devices 40, i.e., in the axial direction A, together with the armature 16, whereas the switching ring 30 is essentially not moved by the armature 16 when the armature 16 moves against the switching direction of the first coupling devices 40, i.e., against the axial direction A. This fact is described in Fig. 5 represented by the block arrow pointing in axial direction A.

[0052] In the decoupled position of the first coupling devices 40, however, the switching ring 30 is neither adjusted in nor against the axial direction A when the armature 16 is adjusted axially.

[0053] When the second coupling devices 42 are in the coupled position, the switching ring 30 is moved in the switching direction of the second coupling devices 42, i.e., opposite to the axial direction A, together with the armature 16, whereas the switching ring 30 is essentially not moved by the armature 16 when the armature 16 moves opposite to the switching direction of the second coupling devices 42, i.e., opposite to the axial direction A.

[0054] In the decoupled position of the second coupling devices 42 (see Fig. 6) However, the switching ring 30 is neither adjusted in nor against the axial direction A when the armature 16 is adjusted axially.

[0055] The coupling elements 44 are pre-tensioned radially inwards towards the switching ring 30 into the coupled position by springs 58, for example by coil springs.

[0056] The spring force of the spring 58 is so low that the coupling element 44 is moved radially outwards and its coupling contour 46 slides over the complementary coupling contour 48 of the shift ring 30 when the armature 16 moves against the direction of shifting. This ensures that the shift element 20 can be moved stepwise in the direction of shifting.

[0057] By axially displacing the control elements 50, 52, the clutch elements 44 can be moved radially outwards against the spring force of the spring 58. This releases them from the switching ring 30.

[0058] The control elements 50, 52 are designed such that in a first axial position of the control elements 50, 52 the first coupling devices 40 are in the coupled position (see Fig. 4) are arranged, while the second coupling devices 42 are arranged in the decoupled position, and in a second axial position of the control elements 50, 52 the second coupling devices 42 are arranged in the coupled position, while the first coupling devices 40 are arranged in the decoupled position.

[0059] The control elements 50, 52 are axially longer than the receptacles 54 are wide (see Fig. 2) and thus project axially beyond the anchor 16 on at least one end face.

[0060] The actuator 10 is designed such that the control elements 50, 52 are pressed against axial stops 60, 62 of the stator assembly 12 when the armature 16 is moved sufficiently close to the axial stops 60, 62. In this way, the control elements 50, 52 can be adjusted between the first axial position and the second axial position by means of the armature 16.

[0061] In the present embodiment (see Fig. 3) The control elements 50, 52 are designed such that the coupling elements 44 of the first coupling devices 40 are moved into the activated state and the coupling elements 44 of the second coupling devices 42 are moved into the deactivated state when the control elements 50, 52 are pressed axially against the first axial stop 60, and the coupling elements 44 of the first coupling devices 40 are moved into the deactivated state and the coupling elements 44 of the second coupling devices 42 are moved into the activated state when the control elements 50, 52 are pressed axially against the second axial stop 62.

[0062] The arrangement shown allows for a bidirectional stepwise movement of the switching element 20, whereby the axial displacement of the armature 16 selectively switches between the two coupling devices 40, 42.

[0063] In an alternative embodiment, the actuator 10 has only first or second coupling devices 40, so that the switching element 20 can only be adjusted in one switching direction, i.e., in or against the axial direction A, by means of the armature 16. In this case, the switching element 20 can be biased against the switching direction, for example by means of a return spring. The spring force of the return spring is correspondingly low so that the coupling elements 44 slip over the teeth during the return movement, thus allowing the switching element 20 to be adjusted stepwise in the switching direction.

[0064] The manner in which the switching element 20 of the actuator 10 is adjusted in axial direction A is described below using the Fig. 8 explained.

[0065] The illustration shows the sequential operation of the actuator 10 in two successive operating states, illustrating the stepwise movement of the switching element 20 by several stroke cycles of the armature 16.

[0066] In the upper area of ​​the Fig. Figure 8 shows the actuator 10 in a first operating state, in which the switching element 20 is arranged in a retracted position.

[0067] In the lower area of ​​the Fig. Figure 8 shows the actuator 10 in a second operating state, in which the switching element 20 is arranged in an extended position which differs from the retracted position by a total stroke H.

[0068] In order to adjust the switching element 20 in axial direction A from the retracted to the extended position, the armature 16 is alternately adjusted in and against the axial direction A by means of the coils 22.

[0069] Here, the first coupling devices 40 are in the coupled position, so that the switching ring 30 is adjusted by a step size W in axial direction A when the armature 16 makes a stroke h in axial direction A.

[0070] During the reverse movement of the armature 16 against the axial direction A, the switching element 20 is not carried along by the armature 16, because the coupling elements 44 of the first coupling devices 40 slide over the switching ring 30, as previously described.

[0071] After several strokes h of the armature 16 and correspondingly many step sizes W of the switching ring 30, for example five, the switching element 20 finally reaches the extended position with the total stroke H, which here corresponds to 5W or 5h.

[0072] In other words, by alternately energizing the coils 22, a stepwise movement of the switching element 20 is achieved, whereby with each stroke cycle of the armature 16 the switching element 20 moves further by a defined step size W, so that the limited stroke h of the armature 16 is multiplied to an increased total stroke H of the switching element 20.

[0073] In order to move the switching element 20 from the extended to the retracted position against the axial direction A, the armature 16 is also moved alternately in and against the axial direction A by means of the coils 22, but the second coupling devices 42 are in the coupled position instead of the first coupling devices 40 and the armature 16 makes a stroke h against the axial direction A from the center position.

[0074] In both cases, no backstop is required because the switching element 20 is not axially loaded, and no external axial force acts on the shaft 28. The inertia and friction or drag torques prevent the coupling elements 44 from significantly displacing the switching ring 30 during the reverse movement; instead, they cause the coupling elements 44 to slip over the teeth.

[0075] In this way, an actuator 10 is provided that combines the advantages of a compact electromagnetic actuator with high pull-in forces and small air gaps with the advantages of large switching paths.

[0076] The bidirectional operation through the two coupling devices 40, 42 allows precise positioning of the switching element 20 in and against the axial direction A, thus opening up diverse application possibilities in vehicle transmissions or other actuating devices.

[0077] Compared to linear drives with multiple coils in series, the Actuator 10 is particularly compact with only two coils.

[0078] The positive locking between the coupling elements 44 and the switching ring 30 ensures that even high switching forces can be effectively transmitted.

[0079] The coupling and mounting of all components ensures defined air gaps, precise position measurements and minimal tilting play.

Claims

[1] Actuator (10) with a stator (14) and an armature (16) forming an electromagnetic drive (18) for a switching element (20) of the actuator (10) extending in an axial direction (A), wherein the actuator (10) is configured to adjust the armature (16) in the axial direction (A) by means of the stator (14), and has at least one coupling device (40) by means of which the switching element (20) can be coupled to the armature (16), wherein in a coupled position of the coupling device (40), the switching element (20) is adjusted in the axial direction (A) together with the armature (16), and in a decoupled position of the coupling device (40), the switching element (20) is not adjusted in the axial direction (A) when the armature (16) is adjusted in the axial direction (A). [2] Actuator (10) according to claim 1, wherein the coupling device (40) is a coupling element (44) with a coupling contour (46) which, in the coupled position of the coupling device (40), engages with a radially opposite, complementary coupling contour (48) of the switching element (20). [3] Actuator (10) according to claim 2, wherein the coupling contour (46) of the coupling element (44) and / or the coupling contour (48) of the switching element (20) is a toothing, in particular with a sawtooth profile. [4] Actuator (10) according to claim 2 or 3, wherein the axial length (L) of the coupling contour (48) of the switching element (20) is greater than the axial length (l) of the coupling contour (46) of the coupling element (44). [5] Actuator (10) according to one of claims 2 to 4, wherein the coupling element (44) is pre-tensioned radially in the direction of the switching element (20) by means of a spring (58). [6] Actuator (10) according to one of claims 2 to 5, wherein the coupling device (40) has at least one control element (50) by means of which the coupling element (44) can be adjusted between an activated state in which the coupling device (40) can be adjusted between the decoupled and coupled positions, and a deactivated state in which the coupling device (40) cannot be adjusted into the coupled position. [7] Actuator (10) according to claim 6, wherein the at least one control element (50) is coupled to the coupling element (44) via a control contour (56), in particular extending in the axial direction (A). [8] Actuator (10) according to claim 6 or 7, wherein the actuator (10) is designed such that the coupling element (44) is moved into the activated state when the at least one control element (50) is pressed axially against a first axial stop (60) of the actuator (10), and is moved into the deactivated state when the at least one control element (50) is pressed axially against a second axial stop (62) of the actuator (10), which is arranged in the axial direction (A) opposite to the first axial stop (60). [9] Actuator (10) according to one of the preceding claims, wherein the actuator (10) has at least a second coupling device (42) by means of which the switching element (20) can be coupled to the armature (16), wherein in a coupled position of the second coupling device (42), the switching element (20) is adjusted together with the armature (16) against the axial direction (A), and in a decoupled position of the second coupling device (42), the switching element (20) is not adjusted against the axial direction (A) when the armature (16) is adjusted against the axial direction (A). [10] Actuator (10) according to one of the preceding claims, wherein the actuator (10) has a first position sensor (34) configured to determine the axial position of the armature (16) relative to the stator (14), and a second position sensor (36) configured to determine the axial position of the switching element (20) relative to the stator (14). [11] Actuator (10) according to one of the preceding claims, wherein the switching element (20) has a shaft (28) and a switching ring (30) which is mounted on the shaft (28) so as to be immovable in the axial direction (A) and rotatable in the circumferential direction, in particular wherein the switching ring (30) is secured against rotation relative to the stator (14).

Images