Electromagnetic actuator for an electromagnetically actuated limited-slip differential, electromagnetically actuated limited-slip differential and vehicle

Abstract

An electromagnetic actuator for an electromagnetically actuated limited-slip differential is proposed. The electromagnetic actuator comprises an electromagnet, an armature, and a sensor target. The armature and the sensor target are arranged radially outwardly of the electromagnet.

Description

The present invention relates to an electromagnetic actuator for an electromagnetically actuated locking differential, an electromagnetically actuated locking differential and a vehicle.A locking differential is a device in a vehicle that allows the wheels to have different speeds, for example, to better maneuver in turns. A locking differential may improve drive to both wheels in certain situations, such as in rough road conditions or off-road driving.An electronically controlled locking differential, also referred to as "eLocker", allows the driver to electronically activate or deactivate the locking function. This may be particularly useful when the vehicle is moving on difficult terrain and additional grip is required. Through the electronic controller, the driver may adjust the behavior of the differential depending on the current driving conditions.A locking differential can be, for example, an electromagnetically actuated locking claw of a differential. For safety reasons, position sensing of the locking pawl state may be required. For example, a sensor can be used to detect the position of the axially movable locking claw. It can thus be detected whether the locking claw and thus the e Are in the locked or in the open state. An arrangement of a position sensor can be made more difficult by various structural limitations. There is therefore a need to provide an improved electromagnetically actuated locking differential, in particular an improved electromagnetic actuator.The object according to the invention is achieved by an electromagnetic actuator for an electromagnetically actuated locking differential, an electromagnetically actuated locking differential and a vehicle according to the independent claims.According to a first aspect, an electromagnetic actuator for an electromagnetically actuated locking differential is proposed. The electromagnetic actuator includes an electromagnet, an armature, and a sensor target. The armature and the sensor target are disposed radially outward from the electromagnet. As a result, a radially required installation space can be reduced. In particular, it is possible to dispense with extending the armature along the electromagnet for arranging the sensor target. As a result, a dimension of the armature and thus of the electromagnetic actuator in the radial as well as in the axial direction can be reduced.In one embodiment, the electromagnet, the armature and the sensor target can be arranged axially overlapping. The axial overlap of the armature, sensor target and electromagnet can reduce an axial expansion of the locking differential.In one exemplary embodiment, the sensor target can be designed to be at least partially circumferential. In particular, the sensor target can be embodied so as to be completely circumferential. Due to the at least partially circumferential configuration of the sensor target, a position sensor which is mounted rotatably with respect to the differential housing can detect the sensor target at different rotational angles of the sensor target relative to the position sensor. This makes it possible to improve position determination by means of the sensor target.In an embodiment, the electromagnetic actuator may further include a locking pawl. The locking claw can be connected to the armature in a force-fit manner, so that a torque can be transmitted from the armature to the locking claw. That is, the locking pawl can receive rotation from the anchor. A rotation of the armature can thus be reduced or stopped via a force transmission to the locking claw. A force transmission for changing a torque of the armature can thus take place via the fastening region with the locking claw.In one exemplary embodiment, the locking claw can have a protrusion on a radial end face. The elevation can have a through-opening for the arrangement of a fastening means. The anchor can have a fastening region. The fastening region may be configured to receive the fastening means, such that the anchor may be fastened to the locking claw by the fastening means, which may extend through the elevation of the locking claw. As a result, a force-fit connection between the anchor and the locking claw can be advantageously produced.In an embodiment, the electromagnetic actuator may further include a position sensor. The position sensor may be decoupled from rotation of the sensor target. Decoupling the rotation of the sensor target from the position sensor makes it possible to simplify a structure or an arrangement of the position sensor.According to a second aspect of the invention, an electromagnetically actuated locking differential is proposed. The locking differential includes a differential housing and an electromagnetic actuator as described above. The sensor target is connected to the differential housing in a rotationally fixed manner. Because the sensor target is connected to the differential housing in a rotationally fixed manner, a construction of the locking differential can be simplified. For example, decoupling between the sensor target and the differential housing, so that the sensor target is rotationally fixed relative to the differential housing, can be dispensed with. Furthermore, the freedom of arrangement of the sensor target can be increased by the rotationally fixed arrangement of the sensor target. For example, the sensor target can be formed positively with the armature.In one embodiment, the locking differential may further include a fastener. The fastening means can produce a force-fit connection between the anchor and the locking claw. Thereby, a torque can be transmitted from the armature to the lock claw properly.According to a third aspect of the invention, a vehicle is proposed. The vehicle includes an electric machine configured to propel the vehicle, the electric machine including an electromagnetically actuated locking differential as described above.In an exemplary embodiment, the vehicle may further include a disconnect system. The electromagnetic actuator or the electromagnetically actuated locking differential can be configured in combination with the disconnect system to decouple the electromagnetic machine from a drive train, such that a connection between the electromagnetic machine and the axle is completely decoupled. As a result, a mass moment of inertia acting on the electromagnetic machine can be reduced or avoided by the drive train.The present invention is to be described below merely by way of example with reference to the attached figures. The following are shown: FIGS. 1 aand 1 b show different views of an electromagnetic actuator 100 for an electromagnetically actuated locking differential; FIGS. 2 aand 2 b show different views of an electromagnetically actuated locking differential; FIGS. 3a-3b show longitudinal sectional views of a locking differential according to FIG. 2 with the locking claw open and the locking claw closed; FIGS. 4a-4c show various views of a locking differential according to the invention; FIGS. 5a-5f show a locking differential according to the invention in comparison with a locking differential from the prior art; FIGS. 6 aand 6 b show the locking differential according to the invention in comparison with a locking differential from the prior art analogous to FIG. 5 ; FIG. 7 shows an embodiment of a vehicle; and FIG. 8 shows a schematic illustration of a combination of an electromagnetic actuator with a disconnect.FIGS. 1 aand 1 b show different views of an electromagnetic actuator 100 for an electromagnetically actuated locking differential. FIG. 1 is a longitudinal sectional view of the electromagnetic actuator 100. FIG. 1B shows a partial section of a longitudinal sectional view of the electromagnetic actuator 100. The actuator 104 includes an electromagnet 130, an armature 110, and a sensor target 120. The armature 110 and the sensor target 120 are disposed radially outward of the electromagnet 130. As a result, a radially required installation space can be reduced.Furthermore, by arranging the armature 110 and the sensor target 120 on a radial outer side, an integration of the armature 110 and the sensor target 120 can take place. Functions of armature 110 and sensor target 120 can thereby be combined in one sub-component. For example, the function of actuation (for example by means of the mechanically movable armature 110) and the function of sensing (for example by means of movable sensor targets) can be implemented integrated in one sub-component.Due to the radially outer arrangement of the armature 110, in addition to the possible functional integration of the armature 110 and the sensor target 120, further advantages can be achieved. For example, functional integration can allow for an axially smaller installation space requirement. For example, as shown in FIG. 1, the sensor target 120 may be disposed in a recess of the armature 110. Furthermore, the positioning of the armature 110 radially outside the electromagnet 130 can allow a radially smaller installation space requirement (see also FIG. 6 ). Furthermore, a reduction in the installation space requirement can enable an integration of a larger electromagnet or a coil in the same overall installation space (see also FIG. 6 ). This allows higher actuating forces and faster switching times to be achieved.In particular, in comparison with the prior art, in which an armature of an actuator is positioned radially on the inside and is guided on the differential cage or differential cover, a simplified and / or more compact design can be achieved. In the prior art, the position sensor is always positioned radially on the outside. Since the position of the locking claw is to be directly sensed, it is necessary to produce a positive or non-positive connection between the locking claw, the armature and the sensor target. In a radially inner arrangement, an "L-shape" system architecture is required. This can require an increased installation space requirement.In one embodiment, the electromagnet 130, the armature 110, and the sensor target 120 may be arranged axially overlapping. The axial overlap of the armature, sensor target and electromagnet can reduce an axial expansion of the locking differential. This allows space to be saved in the axial direction (see also FIG. 6 ).In one exemplary embodiment, the sensor target 120 can be embodied at least partially circumferentially. In particular, the sensor target 120 can be embodied so as to be completely circumferential. Because the sensor target 120 can be at least partially circumferential, the sensor target 120 can be detected by a position sensor 122, which is decoupled from rotation from the sensor target 120, in different positions of the sensor target 120. In particular, the sensor target 120 can be designed such that it can be detected by the position sensor 122 independently of the position of the sensor target 120 relative to the position sensor 122. For example, the sensor target 120 may be formed annularly.As can be seen in FIG. 1 b, the at least partially revolving sensor target 120 can be sensed by the position sensor 122 independently of a relative rotation of the sensor target 120. Accordingly, by means of the at least partially revolving sensor target 120, detection by a position sensor 122, which is decoupled from a rotation of the sensor target 120, can be improved.In an embodiment, the actuator 100 may further include a position sensor 122. The position sensor 122 may be decoupled from rotation of the sensor target 120. By decoupling a rotation of the position sensor 122, an arrangement of the position sensor 122 can be simplified. For example, a Hall sensor or a capacitive sensor may be used as the position sensor 122.In an embodiment, the actuator 100 may further include a locking pawl 150. The locking pawl 150 may be frictionally connected to the armature 110 so that torque may be transmitted from the armature 110 to the locking pawl 150. That is, the locking pawl 150 can receive rotation from the armature 110. As a result, rotation of the armature 110 and the sensor target 120 can be reduced or stopped by the frictional connection with the locking claw 150.In one embodiment, the locking pawl 150 may have a protrusion 152 on a radial end surface. The elevation 152 can have a through-opening 154 for arranging a fastening means. The anchor 110 may include a mounting portion 156. The attachment portion 156 may be configured to receive the fastener such that the anchor 110 may be attached to the locking pawl 150 by the fastener that may extend through the protrusion of the locking pawl 150. As a result, a force-fit connection between the anchor 110 and the locking claw 150 can be advantageously produced.FIGS. 2 aand 2 b show different views of an electromagnetically actuated locking differential 202. FIG. 2 ashows a longitudinal sectional view of the electromagnetically actuated locking differential 202. FIG. 1B shows a partial section of a longitudinal sectional view of the electromagnetically actuated locking differential 202. The locking differential 202 includes a differential housing 140 and an electromagnetic actuator 100, e.g., the electromagnetic actuator 100 as described with reference to FIG. 1. The actuator 104 includes an electromagnet 130, an armature 110, and a sensor target 120. The sensor target 120 is rotationally fixedly connected to the differential case 140.Due to the rotationally fixed arrangement of the sensor target 120, a construction of the locking differential 120 can be simplified. In particular, it is not necessary to decouple a rotation of the differential housing 140 from the sensor target 120.As can be seen in FIG. 2 b, the at least partially revolving sensor target 120 can be sensed by the position sensor 122 independently of a relative rotation of the sensor target 120. Accordingly, by means of the at least partially revolving sensor target 120, a detection of a sensor target 120 connected to the differential housing 140 in a rotationally fixed manner can be improved.Furthermore, the locking differential 202 can also comprise further components such as, for example, a cable duct 232 for the electromagnet 130, a wave spring 260 for transmitting force to the locking claw 150 and / or an axle bevel gear 270.In one embodiment, the locking differential 202 may further include a fastener 258. The fastening means 258 can produce a force-fit connection between the anchor 110 and the locking claw 150. The fastening means 258 can be, for example, a screw connection, a press fit, a securing ring.The locking differential may be, for example, a planetary differential. A number of the planets may be suitably selected.FIGS. 3 a- 3 b show longitudinal sectional views of a locking differential 200 according to FIG. 2 with the locking claw 150 (FIG. 3 a) and the locking claw 150 (FIG. 3 b) open. The locking differential 200 may be a locking differential, such as described with reference to FIG. 2. The locking differential 200 may include an actuator as described with reference to FIG. 1. That is, the actuator may include an electromagnet 130, an armature 110, and a sensor target 120. A sleeve 312 may adjust the position of the armature 110 in cooperation with a wave spring 260.As can be seen in FIG. 3 a, the electromagnet 130 cannot be energized. In this case, no deflection of the armature 110 can take place by the electromagnet 130, i.e. the sleeve 312. The armature 110 can be in a position 1, as indicated by 1. In this case, the locking claw 150 may be opened by the wave spring 260. That is, the wave spring 260 may apply a force to the armature 110 to be positioned for an electroless actuator in a state that allows the locking pawl 150 to open.In FIG. 3 b, the electromagnet 130 is energized. Accordingly, the sleeve 312 may result in deflection of the armature 110. For example, a longitudinal extension of the sleeve 312 may increase. This allows the armature 110 to be moved from the first position to a second position, indicated by 2. Thereby, the locking claw 150 can be brought into a closed position.Because the sensor target 120 is arranged with the armature 110 radially on the outside, a movement of the armature 110 can be transmitted 120 to the sensor target without great constructive complexity. For example, the sensor target 120 and the armature 110 may be integrally fabricated. That is, the sensor target may be disposed in a recess or depression of the armature 110.The sensor target 120 can thus move with the armature 110 from the first position into the second position. Accordingly, a state of the locking claw 150 can be determined via the position of the sensor target 120. Due to the radially outer arrangement of the armature 110, a construction of the electromagnetic actuator can be simplified.The wave spring 160 shown in FIG. 3 is only an exemplary embodiment of a return spring. Alternatively, a coil spring may be used. Furthermore, an arrangement of the restoring spring, i.e. for example of the corrugated spring 160, can be radially flexible. For example, a restoring spring can be arranged radially on the inside or radially on the outside of the electromagnet 130.FIGS. 4a-4c show various views of a locking differential 402 according to the invention. The locking differential 402 may be the same locking differential 402 as described with reference to FIGS. 2 and / or 3. As seen in FIG. 4, the locking differential 402 includes a locking pawl 450. The locking pawl includes a boss 452 including a through hole 454. The through-opening can be configured for the passage of a fastening means 458. The fastener may be disposed in a mounting region 456 of the anchor 410. The anchor can thus be connected in a force-fit manner to the locking claw 450 by the fastening means 458.FIGS. 4 band 4 c show an arrangement of the locking claw 450 within a differential housing 440. The protrusions 452 of the locking claw 450 are arranged in recesses 442 of the differential housing 440. Thereby, power transmission from the lock pawl 450 to the differential case 440 can be improved. In particular, a force transmission can be increased. This ensures that the locking claw 450 can also absorb the forces from the armature and transmit them to the differential housing 440.The protrusion 452 of the locking claw can also be considered as a toothing. That is, the protrusion 452 and the protrusions 452 may form a ratchet tooth. As shown in FIG. 4, the protrusion 452 may be disposed on a radial end surface. In this case, the locking pawl 450 may be a radial pawl. Alternatively, the elevation 452 may also be arranged on an end face. In this case, the locking claw 450 may be a front claw.The differential housing 440 can be embodied in one part or in multiple parts, for example in two parts.FIGS. 5a-5f show a locking differential 502 according to the invention in comparison with a locking differential from the prior art. FIG. 5 ashows a longitudinal sectional view of a locking differential 502 according to the invention. The armature and the sensor target are arranged radially on the outside.FIG. 5 bshows a longitudinal sectional view of a locking differential of the prior art. In contrast to the locking differential according to the invention, the armature is arranged radially on the inside in FIG. 5 b. As a result, an axially outer connection between the armature and the sensor target must be produced in order to connect the radially inner armature to the radially outer sensor target. This connection has an L-shape and can represent an increased design outlay. With the locking differential 502 according to the invention, the design complexity can be reduced.FIG. 5 cshows the same longitudinal sectional view as FIG. 5 a. In FIG. 5 c, the rotating and non-rotating components of the locking differential 502 are highlighted. As can be seen, the sensor target 102 is rotatably arranged. That is, the sensor target 120 is rotationally fixedly connected to the differential case and rotates therewith. In contrast to this (see FIG. 5 d ), the sensor target 520 is arranged in a rotationally fixed manner. That is, in the prior art, the sensor target 520 does not rotate with the differential case. Decoupling the sensor target 520 from a rotation of the differential housing can be complicated in construction. Due to the rotating arrangement of the locking differential 502 according to the invention, a structural outlay for the arrangement of the sensor target 120 can be reduced.FIG. 5e shows the same longitudinal sectional view as FIG. 5a. In FIG. 5 e, a required installation space for the anchor is emphasized. Due to the radially outer arrangement of the armature, a required installation space of the armature can be reduced. In particular, an L-shaped diversion to the sensor target can be dispensed with.In contrast to this (see FIG. 5 f), the anchor in the prior art requires a significantly larger installation space because of the L-shaped diversion. In particular, the L-shaped diversion must have a minimum distance to the electromagnet so that the armature and the sensor target can still move from a first position into a second position. This additionally increases the installation space required.FIGS. 6 aand 6 b show the locking differential 502 according to the invention in comparison with a locking differential from the prior art analogous to FIG. 5. in contrast to FIG. 5, the gain in installation space is shown in FIG. 6 aand a possible enlargement of the coil cross section is shown in FIG. 6 b.As can be seen in FIG. 6 a, a locking differential according to the invention can achieve both a radial gain in installation space (because the armature no longer has a region for arranging the L-shaped component) and an axial gain in installation space (because the L-shaped component is omitted). Alternatively, as shown in FIG. 6 b, a cross section of a coil can be enlarged in the same installation space compared to the prior art.FIG. 7 shows an embodiment of a vehicle 700. The vehicle includes an electric machine 710 configured to propel the vehicle 700. The electric machine 710 comprises an electromagnetic actuator 720, as described, for example, with reference to FIG. 1, or an electromagnetically actuated locking differential, as described, for example, with reference to at least one of FIGS. 2-6.FIG. 8 shows a schematic illustration of a combination of an electromagnetic actuator, e.g. as described with reference to FIG. 1, or an electromagnetically actuated locking differential, e.g. as described with reference to FIGS. 2-5, with a disconnect. FIG. 8 shows an exemplary illustration of a side wave disconnect. A side shaft disconnect system represents a dog clutch controllable by an actuator. This allows decoupling the electromagnetic machine from the drive train. An electromagnetic actuator according to the invention or an electromagnetically actuated locking differential can be combined with a disconnect system. The disconnect system can therefore comprise in particular an electromagnetic actuator according to the invention or an electromagnetically actuated locking differential. For safety reasons, in such an application, the position sensing of the elocker locking pawl may be required in order to be able to reliably detect the state of the elocker. An electromagnetic actuator according to the invention or an electromagnetically actuated locking differential can thus be used both for an electric drive and for an axle transmission.In one exemplary embodiment, the electromagnetically actuated locking differential can be used in combination with a disconnect system which can decouple the electromagnetic machine from a drive train, so that a connection between the electromagnetic machine and the axle is completely resolved. That is, the vehicle may further include a disconnect system. The electromagnetic actuator or the electromagnetically actuated locking differential can be configured in combination with the disconnect system to decouple the electromagnetic machine from a drive train, such that a connection between the electromagnetic machine and the axle is completely decoupledFor example, a second axis can be separated from an electric motor so that the second axis only rotates as well. Transmission of a force from the second axis to the electric motor can thereby be prevented. As a result, in particular a mass moment of inertia acting on the electric motor can be reduced or decoupled.Reference numerals denote reference numerals100 Actuator 110 Armature 120 Sensor target 122 Position sensor 130 Electromagnet 140 Differential housing 150 Locking claw 152 Protrusion 154 Through opening 156 Fastening region 202 Locking differential 232 Cable path Electromagnet 258 Fastening means 260 Wave spring 270 Axle bevel gear 312 Sleeve 402 Locking differential 410 Armature 440 Differential housing 450 Locking claw 452 Protrusion 454 Through opening 456 Fastening region 458 Fastening means 502 Locking differential 520 Sensor target 700 Vehicle 710 Electric machine 720 Electromagnetic actuator 730 Electromagnetically actuated locking differential

Claims

An electromagnetic actuator (100) for an electromagnetically actuated locking differential, comprising: an electromagnet (130); an armature (110); and a sensor target (120), wherein the armature (110) and the sensor target (120) are disposed radially outward of the electromagnet (130)The actuator (100) of claim 1, wherein the electromagnet (130), the armature (110), and the sensor target (120) are arranged axially overlapping.The actuator (100) according to one of the preceding claims, wherein the sensor target (120) is formed at least partially circumferentially.The actuator (100) according to any one of the preceding claims, further comprising a locking pawl (150), wherein the locking pawl (150) is non-positively connected to the armature (110), such that a torque can be transmitted from the armature (110) to the locking pawl (150).The actuator (100) according to claim 4, wherein the locking claw (150) has a protrusion (152) on a radial end face, wherein the protrusion (152) has a through-opening (154) for arranging a fastening means, and wherein the anchor (110) has a fastening region (156), wherein the fastening region is configured to receive the fastening means, such that the anchor (110) can be fastened to the locking claw (150) by the fastening means, which can extend through the through-opening (154) of the locking claw (150).The actuator (100) of any preceding claim, further comprising a position sensor (122), wherein the position sensor (122) is decoupled from rotation of the sensor target (120).An electromagnetically actuated locking differential comprising: a differential housing (240); an electromagnetic actuator (100) according to any preceding claim; wherein the sensor target (120) is rotationally fixedly connected to the differential housing (240).The electromagnetically actuated locking differential of claim 7, further comprising a fastener, wherein the fastener establishes a frictional connection between the armature and the locking pawl.A vehicle (700) comprising: an electric machine (710) configured to propel the vehicle (700), wherein the electric machine (710) comprises an electromagnetic actuator (720) according to any one of claims 1-6 or an electromagnetically actuated locking differential (730) according to any one of claims 7 or 8.The vehicle (700) of claim 9, further comprising a disconnect system, wherein the electromagnetic actuator (720) or the electromagnetically actuated locking differential (730), in combination with the disconnect system, are configured to decouple the electromagnetic machine (710) from a powertrain such that a connection between the electromagnetic machine (710) and the axle is completely decoupled.

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