Electromagnetically actuated limited-slip differential, method for producing an electromagnetically actuated limited-slip differential and vehicle

Abstract

An electromagnetically actuated limited-slip differential is proposed. The electromagnetically actuated limited-slip differential comprises a differential carrier, a differential cover, and a spur gear. The differential cover is connected to the differential carrier by a frictional or positive fit. The spur gear is connected to the differential carrier by a material bond.

Description

[0001] The present invention relates to an electromagnetically actuated limited-slip differential, a method for producing an electromagnetically actuated limited-slip differential and a vehicle.

[0002] A limited-slip differential is a device in a vehicle that allows the wheels to operate at different speeds, for example, to improve maneuverability in corners. A limited-slip differential can improve drive to both wheels in certain situations, such as poor road conditions or off-road driving.

[0003] An electronically controlled or actuated limited-slip differential, also known as an "eLocker," allows the driver to electronically engage or disengage the locking function. This can be particularly useful when the vehicle is traveling over difficult terrain and additional grip is required. Electronic control allows the driver to adjust the behavior of the limited-slip differential depending on the current driving conditions.

[0004] During operation, an electromagnetically actuated limited-slip differential is subjected to strong forces, such as torque, which must be suitably absorbed by the electromagnetically actuated limited-slip differential. For this purpose, a differential cover and a spur gear are connected to the differential carrier via a bolted connection. To transmit or dissipate the torque, special requirements must be placed on the bolted connection. Furthermore, depending on the design, an additional bolted connection may be required for the differential cover if it is not integrated into the spur gear bolted connection of the spur gear. Manufacturing an electromagnetically actuated limited-slip differential using one or more bolted connections can increase the design effort and / or enlarge the design.There is therefore a need to provide an improved electromagnetically actuated limited-slip differential, in particular an improved structure for connecting the differential carrier, differential cover and spur gear.

[0005] The object of the invention is achieved by an electromagnetically actuated limited-slip differential, a method for producing an electromagnetically actuated limited-slip differential and a vehicle according to the independent claims.

[0006] According to a first aspect, an electromagnetically actuated limited-slip differential is proposed. The electromagnetically actuated limited-slip differential comprises a differential carrier, a differential cover, and a spur gear. The differential cover is connected to the differential carrier in a force-locking or form-locking manner. The spur gear is connected to the differential carrier by a material connection. In particular, a torque can be dissipated or dissipated essentially via the material connection between the spur gear and the differential carrier. This means that the force-locking or form-locking connection between the differential cover and the differential carrier can be designed solely for fastening the differential cover to the differential carrier. Accordingly, the force-locking or form-locking connection, for example a screw connection for fastening the differential cover, can be implemented with smaller fastening elements, such as screws.This allows for a reduction in installation space requirements. Furthermore, the integral connection between the spur gear and the differential carrier provides a larger connection point for the transfer or dissipation of torque. This increases the mechanical stability of the limited-slip differential. Power transmission in the limited-slip differential can therefore occur not only via frictional connection, but also (or exclusively) via a material connection.

[0007] In one embodiment, the limited-slip differential can further comprise a locking device. The locking device can be arranged in the differential carrier. This allows a locking torque, i.e., a torque that occurs when the limited-slip differential is locked, to be focused in the differential carrier when the limited-slip differential is locked. In particular, a spread of the torque to the differential cover can be prevented. This allows the structural stability of the connection between the differential cover and the differential carrier to be improved and / or a smaller frictional or positive connection to be used.

[0008] In one embodiment, the differential cover may include a through-hole for the passage of an actuator of the locking device. This allows the actuator to be arranged outside the differential cover, and the locking device to be controlled inside the differential carrier.

[0009] In one embodiment, the spur gear can have a step on a side facing the differential carrier. The step can be designed as an axial stop for placement on the differential carrier. This can simplify the arrangement of the spur gear for a materially bonded connection to the differential carrier. Furthermore, the step can apply an axial toothing force to the spur gear and the differential carrier. This can improve the arrangement of the spur gear on the differential carrier.

[0010] In one embodiment, torque flow in the limited-slip differential can occur solely via the material connection between the spur gear and the differential carrier. Accordingly, the frictional or positive connection between the differential cover and the differential carrier can be designed solely to enable attachment of the differential cover to the differential carrier. The frictional or positive connection can thus be designed such that no torque transfer or dissipation is required. Accordingly, the frictional or positive connection can be made smaller, for example, by using smaller fasteners. This allows the installation space of the limited-slip differential to be reduced.

[0011] In one embodiment, torque flow in a locked state of the limited-slip differential can occur independently of the differential cover. This means that stress on the frictional or positive connection between the differential cover and the differential carrier can be reduced or avoided even in the locked state, particularly by arranging the locking device within the differential carrier.

[0012] In one embodiment, the integral connection can be a welded joint. This allows the spur gear to be connected to the differential carrier in a simplified manner.

[0013] According to a second aspect of the invention, a vehicle is proposed. The vehicle comprises an electric machine configured to drive the vehicle, wherein the electric machine comprises an electromagnetically actuated limited-slip differential as described above.

[0014] According to a third aspect of the invention, a method for manufacturing an electromagnetically actuated limited-slip differential is proposed. The method comprises providing a differential carrier. Furthermore, the method comprises arranging a spur gear on the differential carrier in a materially bonded manner. Furthermore, the method comprises arranging a differential cover on the differential carrier in a force-fitting or form-fitting manner. This allows for the manufacture of an electromagnetically actuated limited-slip differential with a reduced installation space requirement.

[0015] In one embodiment, the method may further comprise grinding the spur gear after it has been firmly arranged on the differential carrier (and before the differential cover is arranged). Accordingly, the spur gear can still be ground even after it has been arranged on the differential carrier. This can result in greater design freedom. In particular, the spur gear can be ground after the spur gear has been assembled with the differential carrier. This can, in particular, reduce noise, vibration, and / or roughness when using a limited-slip differential according to the invention.

[0016] The present invention will be described below by way of example only, with reference to the accompanying figures. They show: Fig. 1a and Fig. 1b show different perspective views and Fig. 1c a sectional view of an electromagnetically actuated limited-slip differential; Fig. 2a and Fig. 2b show detailed views of the sectional view of the limited-slip differential from Fig. 1 for different states of the limited-slip differential; Fig. 3 shows an embodiment of a vehicle; and Fig. 4 shows a flowchart of a method for manufacturing an electromagnetically actuated limited-slip differential.

[0017] Fig. 1a and Fig. 1b show different perspective views and Fig. 1c shows a sectional view of an electromagnetically actuated limited-slip differential 100. The electromagnetically actuated limited-slip differential 100 comprises a differential carrier 110, a differential cover 120, and a spur gear 130. The differential cover 120 is connected to the differential carrier 110 in a force-locking and / or form-locking manner. For example, the differential cover 120 can be connected to the differential carrier 110 with a fastening means, such as a screw or a rivet. In a force-locking connection, the strength of the connection can depend primarily on the friction between the contact surfaces of the components, which is generated by the fastening means. Here, the tightening force of the fastening means can play a decisive role.Alternatively, in a positive-locking connection, the strength may depend less on friction and more on the specific shapes and profiles of the fastener and the area for arranging the fastener. The fastener may then serve more to maintain a position-specific shape. This means, for example, in a screw connection, a force-locking connection may dominate (for example, if strength can be adjusted via a screw force), a form-locking connection may dominate (for example, in interaction with a tongue and groove), or strength may be ensured by a combination of force and form locking. In particular, the differential cover 120 may not be integrally connected to the differential carrier 110.

[0018] The spur gear 130 is integrally connected to the differential carrier 110. The integral connection 132 of the spur gear 130 to the differential carrier 110 eliminates the need for a frictional and / or positive connection 122. For example, a screw connection for connecting the spur gear 130 and the differential carrier 110 can be dispensed with. This means that torque can no longer be transmitted or diverted via a screw connection. Instead, the torque in the limited-slip differential 100 can be transmitted or diverted via the integral connection 132 between the spur gear 130 and the differential carrier 110. By transmitting or diverting the torque via the integral connection 132, an area for transmitting or diverting the torque can be enlarged. In particular, compared to the use of a screw connection, the use of screw connections can be completely dispensed with.

[0019] In known systems, high demands are placed on the screw connection between the differential carrier and the spur gear due to the torque being dissipated or transferred via screw connections between the differential carrier and the spur gear. For example, this screw connection must be of a certain size to provide minimum stability for a limited-slip differential. The inventors have discovered that the torque dissipation or transfer can be improved by providing a material-to-material connection 132 between the spur gear 130 and the differential carrier 110. This eliminates the need for a complex construction with a screw connection, which increases the installation space required. The material-to-material connection 132 allows the installation space required to be reduced.Furthermore, a dimension of the integral connection 132 can be varied without substantially changing the installation space required for the limited-slip differential 100. The integral connection 132, for example, a weld seam, a soldered connection, or an adhesive connection, can be adapted from a dimension, for example, a width, within the scope of the dimensions of the spur gear 130 and the differential carrier 110. This allows, for example, a dissipated or dissipated torque to be increased without changing the installation space of the limited-slip differential 100. In contrast, when using a screw connection, a dissipated or dissipated torque can be increased simply by enlarging the screw connection.

[0020] The limited-slip differential 100 according to the invention can therefore offer a number of advantages. A large screw connection for torque transmission between the differential carrier 110 and the spur gear 130 can be eliminated. This allows a limited-slip differential 100 to be provided with a reduced installation space. Furthermore, torque transmission can be achieved by a material connection. This allows a torque transmission area to be adapted to a specific application without significantly changing the installation space. Furthermore, the spur gear 130 can be ground in an installed state. Furthermore, the electromagnetically actuated limited-slip differential 100 can have a combination of a material connection 132 and a non-positive or positive connection 122. For example, the differential carrier 110 can be a 4-planetary differential carrier.

[0021] In one embodiment, the limited-slip differential 100 may further comprise a locking device 140. The locking device 140 may be arranged in the differential carrier 110. By arranging the locking device 140 in the differential carrier 110, a torque flow in a locking case, i.e., in a locked state of the limited-slip differential 100, may take place directly in the differential carrier 110 (see also Fig. 2b). This allows for a reduction or avoidance of stress on the frictional or positive connection 122 between the differential carrier 110 and the differential cover 120 in a locked state. Accordingly, a frictional or positive connection 122 between the differential carrier 110 and the differential cover 120 can be simplified in design. In particular, the required installation space for the frictional or positive connection 122 can be reduced.

[0022] In one embodiment, the differential cover 120 can include a through-opening 150 for the passage of an actuator of the locking device 140. The actuator can be a coil (i.e., an electromagnetic actuator), a shift drum, an electric motor, or a hydraulic or pneumatic actuator. This means that the locking device 140 can be controlled within the differential carrier 110 through the through-opening 150. Accordingly, a part and / or a supply line of the actuator can extend through the through-opening 150. The through-opening 150 can enable a simplified arrangement of the locking device 140 within the differential carrier 110. Accordingly, the actuator can be arranged outside the differential cover 120. This means that the limited-slip differential 100 can include a locking device 140, i.e., a locking mechanism, in the differential carrier 110 instead of in the differential cover 120.This may, as described above, enable direct torque flow within the differential carrier 110 without torque flow within the differential cover 120 for a locked condition of the limited-slip differential 100.

[0023] In one embodiment, the spur gear 130 can have a step 160 on a side facing the differential carrier 110. The step 160 can be designed as an axial stop for arrangement on the differential carrier 110. Accordingly, the differential carrier 110 can also include a step for arrangement on the step 160 of the spur gear 130. The step 160 of the spur gear 130 can form a toothing force in interaction with the step of the differential carrier 110 and the integral connection 132. This can improve the arrangement of the spur gear 130 on the differential carrier 110.

[0024] In one embodiment, torque flow in the limited-slip differential 100 can occur solely via the material connection 132 between the spur gear 130 and the differential carrier 110. Accordingly, the frictional or positive connection 122 between the differential cover 120 and the differential carrier 110 can be configured solely to enable attachment of the differential cover 120 to the differential carrier 110. However, force dissipation or transmission need not be provided by the frictional or positive connection 122. This can simplify the design of the frictional or positive connection 122.

[0025] In one embodiment, a torque flow in a locked state of the limited-slip differential 100 can occur independently of the differential cover 120. This means that a load on the force-locking or form-locking connection 122 between the differential cover 120 and the differential carrier 110 does not need to be designed to dissipate or dissipate force.

[0026] In one exemplary embodiment, the material-to-material connection 132 can be or comprise a welded connection 132. Alternatively or optionally, the material-to-material connection 132 can be or comprise a soldered connection and / or an adhesive connection. For example, a weld seam can be combined with an adhesive connection. This allows the spur gear 130 to be connected to the differential carrier 110 in a simplified manner. In particular, a size of the material-to-material connection 132, for example of the welded connection 132, can be easily adjusted. The material-to-material connection 132 can be at least partially circumferential along an end face of the spur gear 130. In particular, the material-to-material connection 132 can be completely circumferential. A width of the material-to-material connection 132 can be adapted to an application.The material connection 132 is at least 0.5 mm, or at least 1 mm, or at least 2 mm, or at least 3 mm wide and / or at most 6 mm, or at most 5 mm, or at most 4 mm. The frictional or positive connection 122, however, can only be designed in such a way that a (secure) attachment of the differential cover 120 to the differential carrier 110 is ensured. For example, the frictional or positive connection 122 can be a screw connection 122.

[0027] Fig. 2a and Fig. 2b show detailed views of the sectional view of the limited-slip differential 100 from Fig. 1 for different states of the limited-slip differential 100. The limited-slip differential 100 comprises, as with reference to Fig. 1, a differential carrier 110, a differential cover 120 and a spur gear 130. Fig. Figure 2a shows the torque flow for a normal operating state, i.e., a non-locked state, of the limited-slip differential 100. The torque flow is indicated by the black arrows. As can be seen, the torque flow is not diverted or dissipated via the differential cover 120. The torque flow is diverted or dissipated solely between the differential carrier 110 and the spur gear 130.

[0028] Fig. Figure 2b shows the torque flow for a locked state of the limited-slip differential 100. The additional torque flow due to the locked state is indicated by the dashed arrows. As can be clearly seen, the additional torque flow due to the locked state is limited to the differential carrier 110. By arranging the locking device within the differential carrier 110, the torque flow can be separated from the differential cover 120. This can reduce the stress on the frictional or positive connection between the differential carrier 110 and the differential cover 120.

[0029] Fig. 3 shows an embodiment of a vehicle 300. The vehicle includes an electric machine 310 configured to drive the vehicle 300. The electric machine 310 includes an electromagnetically actuated limited-slip differential 320, such as with reference to at least one of the Fig. 1 or Fig. 2 is described.

[0030] Fig. 4 shows a flowchart of a method 400 for manufacturing an electromagnetically actuated limited-slip differential. The method 400 can be used, for example, to manufacture a limited-slip differential as described with reference to Fig. 1 or Fig.2 described. The method 400 comprises providing 410 a differential carrier. Furthermore, the method 400 comprises materially bonded 420 a spur gear to the differential carrier. Furthermore, the method 400 comprises force-fitting or form-fitting 430 a differential cover to the differential carrier. This makes it possible to produce an electromagnetically actuated limited-slip differential with a reduced installation space requirement. In one exemplary embodiment, the method 400 can further comprise grinding 440 the spur gear after the materially bonded 420 arrangement (and before the force-fitting and / or form-fitting arrangement 430) on the differential carrier. In conventional screw connections between the spur gear and the differential carrier, the differential cover and other components, such as electronic components, are often also fastened to the differential carrier with the screw connection. That is to sayAfter arranging the spur gear by means of a screw connection to the differential carrier, grinding the spur gear may be impossible without damaging other components of the limited-slip differential. By arranging the spur gear 420 to the differential carrier with a material connection, however, the spur gear can be arranged on the differential carrier separately (i.e., before arranging the differential cover). Accordingly, even after arranging the spur gear to the differential carrier, grinding of the spur gear can still be performed. Grinding the spur gear before arranging it on the differential carrier and the associated more complex manufacturing process can thus be simplified.

[0031] Optionally, a press fit of the spur gear to the differential carrier can be implemented, particularly for centering and optionally for power transmission. Using the press fit or a press fit, the spur gear can be centered on the differential carrier for the material-to-material assembly 420, e.g., a welding process, and optionally arranged in a force-to-material manner. This can simplify the material-to-material assembly 420.

[0032] Optionally, part of the force transmission can be carried out via the press set (depending on the design) in addition to the material bond. Reference symbol 100 electromagnetically actuated limited slip differential 110 Differential cage 120 differential cover 122 force-locking or form-locking connection 130 spur gear 132 positive connection 140 locking device 150 passage opening 160 level 300 vehicles 310 electric machine 320 electromagnetically actuated limited slip differential 400 Method for producing an electromagnetically actuated limited-slip differential 410 Providing a differential carrier 420 material-to-material arrangement of a spur gear 430 force-fitting or form-fitting arrangement of a differential cover 440 Grinding the spur gear

Claims

[1] An electromagnetically actuated limited-slip differential (100) comprising: a differential carrier (110); a differential cover (120), wherein the differential cover (120) is connected to the differential carrier (110) in a force-locking or form-locking manner; and a spur gear (130), wherein the spur gear (130) is integrally connected to the differential carrier (110). [2] The limited-slip differential (100) according to claim 1, further comprising a locking device (140), wherein the locking device (140) is arranged in the differential carrier (110). [3] The limited-slip differential (100) according to claim 2, wherein the differential cover (120) comprises a through-opening (150) for the passage of an actuator of the locking device (150). [4] The limited-slip differential (100) according to one of the preceding claims, wherein the spur gear (130) has a step on a side facing the differential carrier (110), the step being designed as an axial stop for arrangement on the differential carrier (110). [5] The limited-slip differential (100) according to one of the preceding claims, wherein a torque flow in the limited-slip differential (100) occurs solely via the material connection (122) between the spur gear (130) and the differential carrier (110). [6] The limited-slip differential (100) according to any one of the preceding claims, wherein a torque flow in a locked state of the limited-slip differential (100) occurs independently of the differential cover (120). [7] The limited-slip differential (100) according to one of the preceding claims, wherein the material connection (122) is a welded connection. [8] A vehicle (300) comprising: an electric machine (310) configured to drive the vehicle (300), wherein the electric machine (310) comprises an electromagnetically actuated limited-slip differential (320) according to one of the preceding claims. [9] A method (400) for manufacturing an electromagnetically actuated limited-slip differential, comprising: Providing (410) a differential carrier; materially arranging (420) a spur gear on the differential carrier; and force-fitting or form-fitting arrangement (430) of a differential cover on the differential carrier. [10] The method (400) of claim 9, further comprising grinding (440) the spur gear after said integrally arranged (420) on the differential carrier.

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