Locking differential for a motor vehicle, and motor vehicle

Abstract

The invention relates to a locking differential (10) for a motor vehicle, comprising a differential housing (12) that can be rotated about a rotational axis and encloses a receiving space (14); two output wheels (16) that can be rotated relative to one another about the rotational axis; at least one compensating wheel (16) that is mounted in the receiving space (14) and is held on the differential housing (12) so as to be rotatable about a rotational axis, which is non-rotatably fixed to the differential housing (12), by means of a compensating pin (17), which is secured to the differential housing (12), the compensating wheel resting against each of the output wheels (16); and a differential lock (18) comprising a plate stack (20), the differential housing (12) having at least one first oil supply channel (34) with an inlet opening (38) and an outlet opening (40), by means of which oil (32) can be guided to the plate stack (20), and at least one second oil supply channel (36), by means of which oil (32) can be guided into the receiving space (14).

Description

[0001] 24-2274

[0002] 1

[0003] Limited-slip differential for a motor vehicle and motor vehicle

[0004] The invention relates to a locking differential for a motor vehicle and a motor vehicle.

[0005] From EP 2574827 B1, a clutch assembly for a motor vehicle is known for transmitting drive power from the motor vehicle to a wheel of an axle with a switchable clutch device, capable of transmitting drive power from a drive element on the drive side with respect to the clutch device to a drive element on the output side with respect to the clutch device. An oil supply device for clutch lubrication is provided, which supplies oil from an oil circuit servicing the clutch device depending on the operating conditions. The clutch assembly is mounted in a housing that forms a clutch chamber for receiving the clutch device. Furthermore, a draining device is provided, which drains oil from the clutch chamber when the oil supply device is not operating.

[0006] Furthermore, a differential gear, particularly for motor vehicles, is known from DE 1 123214 B, in which the axle shaft bevel gears, located coaxially to the driven differential gear, are each connected to one of the axle shafts. The differential gear has slip clutches arranged between the differential gear housing and the axle shafts. These slip clutches are located in a cylindrical housing connected to the differential gear and contain a pack of clutch plates. These plates are pressed together under preload by means of springs located in extension of the clutch plate pack and are alternately engaged with the 24-2274

[0007] 2

[0008] The axle drive unit is connected to the cylindrical housing or the axle shafts of the differential. The oil level in the axle housing is slightly lower than the lowest point on the outer surface of the housing. Therefore, a sheet metal ring is press-fitted to the outer surface of the housing near its inner end. This ring contains outward-facing, triangularly shaped vanes, formed as a single piece with the ring, which are spaced at intervals around the circumference. Openings serving as oil channels are provided in the housing wall below each vane, near the point where the vane joins the circumference of the ring. When the axle drive unit rotates, the oil vanes dip into an oil sump located between the axle housing and the housing.

[0009] The object of the present invention is to provide a solution which enables particularly efficient and reliable cooling of a multi-plate clutch of a particularly compact limited-slip differential.

[0010] This problem is solved according to the invention by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the dependent claims, the description, and the figures. Features, advantages, and possible embodiments set forth in the description for one of the subject matter of the independent claims are to be regarded, at least analogously, as features, advantages, and possible embodiments of the respective subject matter of the other independent claims, as well as of any possible combination of the subject matter of the independent claims, optionally in conjunction with one or more of the dependent claims.

[0011] The invention relates to a limited-slip differential for a motor vehicle. A limited-slip differential is a differential gear often used in motor vehicles. If one wheel of the motor vehicle spins, the limited-slip differential transmits a greater amount of torque to the other wheel so that the driving force is not limited by the low traction of the spinning wheel. The limited-slip differential in this case is a differential gear with a differential lock. The differential gear, which can also be called a differential transmission, is a planetary gear transmission with one input and two outputs. The differential gear is therefore a distribution transmission. The differential gear is designed to distribute a torque supplied by the motor vehicle's engine between two 24-2274

[0012] 3

[0013] The differential gear is used to distribute power between the driven wheels of the motor vehicle. It is therefore an axle differential.

[0014] A differential lock allows torque to be redirected from the faster-rotating output shaft to the slower-rotating one. In other words, the faster output shaft can be slowed down to benefit the slower one. In this case, the locking differential comprises a driveable differential housing that rotates around a pivot axis and encloses a receiving chamber. This differential housing is a differential carrier of the differential gear. Furthermore, the locking differential includes two output gears that rotate relative to each other around the pivot axis. These gears are located within the receiving chamber and are rotatable relative to the differential housing. The respective output gears can, for example, be conical in shape. Thus, the respective output gears can be considered output cones.Each of the output gears is designed to be rotationally fixed to one of the vehicle's wheels, thus enabling each output gear to drive one of the vehicle's wheels. Furthermore, the limited-slip differential comprises at least one compensating gear located in the receiving space, which is rotatably held on the differential housing about a compensating axis that is fixed relative to the differential housing by means of a compensating bolt attached to the differential housing. In other words, the compensating bolt is fixed in its longitudinal direction relative to the differential housing. Therefore, if the differential housing rotates about the axis of rotation, the compensating bolt rotates with the differential housing.At least one compensating gear is mounted on the compensating bolt, thereby holding the compensating gear to the differential housing and allowing it to rotate relative to the differential housing about the compensating axis defined by the compensating bolt. The compensating gear bears against each of the output gears and is designed to transmit a rotational movement of one output gear to another or to compensate for a relative rotation of the output gears to each other.

[0015] The differential housing thus serves as a carrier for at least one differential gear. The differential gear is therefore a planetary gear of the differential transmission. It is possible that the locking differential comprises several differential gears arranged in the receiving space, each differential gear having its own offset defined by a respective offset pin.24-2274

[0016] 4

[0017] The compensating axis is rotatable relative to the differential housing. Each of the compensating gears is designed to bear against both output gears in order to transmit a rotational movement of one of the output gears to the other of the output gears or to compensate for a relative rotation of the output gears to each other about the axis of rotation.

[0018] The differential lock of the limited-slip differential comprises a multi-plate clutch pack. The differential lock is designed to be adjustable between a locked state, in which the first of the output gears is rotationally fixed to the differential housing, and a disengaged state, in which the multi-plate clutch pack allows relative rotation of the first output gear with respect to the differential housing. The differential lock is therefore designed as a multi-plate clutch. This multi-plate clutch is a torque-dependent differential lock. The multi-plate clutch pack establishes a frictional connection between the differential housing and the outputs.

[0019] In the limited-slip differential, the clutch pack and an actuating device for adjusting the clutch pack's state are arranged on axially opposite sides of the compensating bolt, each radially overlapping one of the differential gears. The clutch pack is fluidly separated from the receiving space by means of a clutch pack end plate. The actuating device allows the clutch pack to be adjusted between the locked and unlocked states. The axial direction is parallel to the longitudinal direction of rotation of the differential housing or the output gears. Thus, the clutch pack and its associated actuating device are arranged on axially opposite sides of the at least one compensating bolt.Furthermore, the clutch pack and the actuating device are arranged such that they each radially overlap one of the differential gears at least partially. The limited-slip differential thus has a particularly short axial extension. It is therefore provided that the clutch pack radially overlaps at least partially one of the differential gears, and the actuating device radially overlaps at least partially one of the differential gears. Because the actuating device and the clutch pack are arranged on axially opposite sides of the at least one compensating bolt, the clutch pack end disk 24-2274 is

[0020] 5

[0021] The clutch pack is arranged axially facing the compensating bolt. This means that the clutch pack is sealed by the clutch pack end plate on the side facing the compensating bolt in the axial direction. The clutch pack end plate is designed to seal the clutch compartment of the limited-slip differential, in which the clutch pack is housed, at least fluid-tight, and in particular fluid-tight, from the receiving space. This prevents fluid from flowing directly from the clutch compartment into the receiving space, in which the differential gears and the output gears are located. In particular, it is provided that both the clutch pack and the at least one differential gear or the output gears are cooled by means of a cooling fluid, in this case oil. For this purpose, oil must be supplied to both the clutch pack and the receiving space.The oil can also be used to lubricate the drive wheels and at least one compensating wheel.

[0022] The differential housing has at least one first oil supply channel with an inlet and an outlet, through which oil can be supplied to the clutch pack. Furthermore, the differential housing has at least one second oil supply channel through which oil can be supplied to the receiving chamber. Thus, the differential housing is provided with two oil supply channels that are at least partially separate from each other: the first oil supply channel and the second oil supply channel. This ensures that oil can be supplied to both the clutch pack and the receiving chamber of the differential housing via the respective oil supply channels. This ensures reliable cooling and lubrication of the clutch pack, the output gears, and the at least one differential gear.

[0023] In a possible further development of the invention, it is provided that an edge limiting the inlet opening of the first oil supply channel rearward in the direction of rotation of the differential housing about the axis of rotation is formed with an angle tapering to a point in the cross-section perpendicular to the axial direction, whereby oil from an oil jet directed towards the inlet opening can be scooped into the first oil supply channel by means of this edge. In other words, the inlet opening of the first oil supply channel is formed with respect to the direction of rotation,24-2274

[0024] 6

[0025] The differential housing, which rotates around its axis of rotation during operation, is bounded at the rear by a tapered edge. This rear edge cuts off the oil jet directed towards the inlet opening. This ensures reliable oil flow into the first oil supply channel by means of the rear, tapered edge that defines the inlet opening of the first oil supply channel. The inlet opening of the first oil supply channel is thus bounded at the rear by a sharp edge, which cuts off the oil jet directed towards the inlet opening. This allows for particularly reliable oil delivery into the first oil supply channel and prevents oil from flowing out of the first oil supply channel through the inlet opening.

[0026] In a further possible embodiment of the invention, an edge defining the inlet opening of the first oil supply channel in the direction of rotation of the differential housing about the axis of rotation is provided by a plate-shaped planing element or a scoop-shaped blade element attached to the differential housing. The planing element can be sharp and thin, similar to a razor or razor blade. It is possible for the planing element to be made of a metallic material. In particular, the planing element is a razor or razor blade. It is specifically provided that the planing element does not project radially outwards beyond any area of ​​the differential housing surrounding the planing element and thus is flush with the differential housing. For this purpose, the planing element can be arranged in a recess of the differential housing.The particularly sharp edge provided by the blade element, which limits the rearward boundary of the inlet opening, allows oil to be effectively bladed from an oil jet directed at the inlet opening and thus reliably guided into the first oil supply channel. The edge provided by the blade element, which limits the rearward boundary of the inlet opening, can have a freely selectable profile. For example, the edge can be straight or have a radial curvature. The blade element can project radially beyond a surrounding area of ​​the differential housing. The blade element can have a radially outward curvature, which enables a particularly large amount of oil from the oil jet directed at the inlet opening to be drawn into the first oil supply channel.24-2274

[0027] 7

[0028] It can be scooped. The scoop element can, for example, be glued onto the differential housing.

[0029] In a further possible embodiment of the invention, the lamellar assembly has a distribution channel formed by recesses, in particular grooves, in several lamellae of the lamellar assembly. The distribution channel extends at least partially in the axial direction, allowing oil flowing to the lamellar assembly to be guided and / or distributed axially by means of the distribution channel. The distribution channel is particularly located on the outer surface of the lamellar assembly. The distribution channel can extend parallel or obliquely to the axial direction. The distribution channel allows oil flowing into the lamellar space to be distributed particularly well between the lamellae or to be guided to all lamellae, thus ensuring that a particularly large number of the lamellae of the lamellar assembly are cooled and lubricated effectively.

[0030] In another possible embodiment of the invention, the outlet opening opens into the lamellar chamber in which the clutch pack is arranged. In this embodiment, a first edge of the differential housing, defining the outlet opening towards the compensating bolt, has a greater axial distance to the compensating bolt than an edge of the differential housing defining the inlet opening towards the compensating bolt. Alternatively or additionally, a second edge defining the outlet opening and located axially opposite the first edge has a greater axial distance to the compensating bolt than an edge of the differential housing defining the inlet opening on the side facing away from the compensating bolt. This directs oil flowing in the first oil supply channel axially towards the end disk of the clutch pack.The end disk of the lamellar pack limits the lamellar pack axially on one side of the lamellar pack facing the compensating bolt. The described design of the edge and the outlet opening in relation to the edges of the inlet openings of the first oil supply channel results in the first oil supply channel extending axially away from the compensating bolt with its longitudinal direction from the radially outer inlet opening to the radially inner outlet opening. In other words, the inlet opening of the first oil supply channel is axially closer to the 24-2274.

[0031] 8

[0032] The compensating bolt is positioned as the outlet of the first oil supply channel. Oil can thus be guided into the clutch chamber via this first oil supply channel in both an axial direction away from the compensating bolt and a radial direction from the outside to the inside. Consequently, the clutch pack located in the clutch chamber can be subjected to an oblique oil flow. This significantly reduces the risk of oil being thrown radially away from the clutch pack due to rotation of the clutch pack, which is fixed to the differential housing. Reliable lubrication of the clutch pack with oil is therefore ensured.

[0033] In this context, it can be specifically designed that the lamellar space forms a radial undercut towards the outlet opening, allowing the oil to collect in the undercut. Specifically, an oil pool forms in the undercut, with the radial height of the undercut determining the amount of oil that can accumulate. An oil level within this pool extends axially and in the direction of rotation. This undercut causes oil flung radially from the lamellar assembly due to its rotation around the axis of rotation to collect in the undercut, thus forming a kind of oil sump within the undercut. The oil collected in the undercut can then be used to lubricate and cool the lamellar assembly.In particular, it is intended that at least one lamella, especially several individual lamellae, protrude into the oil sump in the undercut, which allows these lamellae to be cooled particularly well by means of the oil.

[0034] In this context, it can be provided, in particular, that the undercut deepens radially with increasing axial distance from an outlet opening. This means that the greater the axial distance of a region of the undercut from the outlet opening, the further the undercut projects radially beyond the outlet opening. This ensures that the oil flowing into the lamellar chamber flows axially within the lamellar chamber due to the undercut deepening with axial distance from the outlet opening, thus guaranteeing that a particularly large number of the lamellae arranged in the lamellar chamber can be cooled by contact with the oil. Furthermore, the further the oil is axially from the outlet opening, the more radially the oil flows due to the radial deepening of the undercut.

[0035] 9

[0036] As the oil flows outwards, it is guided in an axial direction away from the outlet opening into the lamellar space due to centrifugal forces acting on the oil, particularly along the lamellar pack.

[0037] In a further possible embodiment of the invention, the limited-slip differential is designed such that, in a first section of a circumferentially extending oil path, the oil is guided radially inwards through the differential housing, and in a second section of the oil path, adjoining the first section in the circumferential direction, the oil is guided radially outwards between axially adjacent lamellae. In the second section of the oil path, the oil flows circumferentially and axially between adjacent lamellae. In the second section, the radial height of the lamellae increases with increasing circumferential distance from the first section. This radial design of the lamellae, combined with centrifugal forces acting on the oil, assists the oil flowing circumferentially through the oil path.The centrifugal forces acting on the oil cause it to be conveyed or accelerated circumferentially in the second section of the oil path. A drain channel can be connected to this second section, through which the oil must flow so that it can flow out of the differential housing.

[0038] In another possible embodiment of the invention, the outlet opening is arranged further rearward in the circumferential direction than the inlet opening. This allows the oil to flow particularly easily and reliably through the first oil supply channel from the inlet opening to the outlet opening, since inertial forces acting on the oil flowing into the first oil supply channel via the inlet opening can be used to guide the oil through the first oil supply channel. In other words, the oil flows into the first oil supply channel and the differential housing continues to rotate circumferentially while the oil is in the first oil supply channel.Because the differential housing moves circumferentially and certain inertial forces act on the oil that has flowed into the first oil supply channel, the differential housing moves relative to the oil in the circumferential direction, or the oil arranged in the first oil supply channel moves relative to the differential housing in the opposite direction to the circumferential direction.24-2274.

[0039] 10

[0040] In a further possible embodiment of the invention, the differential housing has at least one oil draining channel with an oil draining inlet and an oil draining outlet, which are arranged circumferentially offset from the inlet of the first oil supply channel. This means that the oil draining outlet overlaps the inlet of the first oil supply channel over a circumferential axial length. The oil draining outlet and the inlet of the oil supply channel are spaced apart circumferentially. For example, the differential housing can have several first oil supply channels and several oil draining channels, with an inlet of the first oil supply channel and an oil draining outlet alternately arranged radially on the outer surface of the differential housing in the circumferential direction.The at least one oil removal channel enables defined oil removal from the lamellar space by directing oil away from the lamellar space via the at least one oil removal channel.

[0041] In this context, it can be specifically designed that the oil drain opening covers the lamellar assembly in a circumferential section of the lamellar assembly over its entire axial length. This means that in this circumferential section, the entire lamellar assembly is radially covered outwards by the oil drain opening, through which the oil can flow from the lamellar chamber into the oil drain channel. This ensures reliable oil removal from the lamellar chamber via the oil drain channel. By selecting a flow cross-section for the oil drain channel, for example by adjusting the circumferential length of the circumferential section, the volume flow rate of the oil flowing in the oil drain channel can be controlled.By adjusting this flow rate, the residence time of the oil in the lamellar chamber can be set before it flows out of the lamellar chamber via the drain channel. The oil residence time in the lamellar chamber controls the cooling of the lamellar pack. Because the drain inlet extends over the entire axial length of the lamellar pack, the risk of an oil pool forming, where oil that no longer flows out of the lamellar chamber collects and remains there permanently, is significantly reduced. Thus, the formation of [24-2274]

[0042] 11

[0043] Dead zones, where oil accumulates and no longer flows out, should be kept to a minimum.

[0044] In another possible embodiment of the invention, a nozzle of a pressurized oil line is directed towards the inlet opening of the first oil supply channel, allowing oil to be sprayed onto the inlet opening by means of the nozzle. The nozzle, and in particular at least a portion of the pressurized oil line, can be part of the limited-slip differential. The pressurized oil line is designed to supply pressurized oil, and thus pressurized oil, to the nozzle. The nozzle can direct the oil towards the inlet opening to ensure that a particularly large amount of the oil supplied by the nozzle flows into the first oil supply channel via the inlet opening.It is possible to use two nozzles. One nozzle directs the oil towards the inlet of the first oil supply channel, while the second nozzle directs it towards a different inlet of the second oil supply channel. This ensures that oil flows into the finned space via the first oil supply channel and into the receiving chamber via the second oil supply channel. The first nozzle directs the oil towards the inlet of the first oil supply channel, resulting in a particularly high percentage of the directed oil jet actually entering the first oil supply channel. This enables highly reliable and efficient cooling of the fins within the fin pack.

[0045] The invention further relates to a motor vehicle with a drivetrain comprising a locking differential, as already described in connection with the locking differential according to the invention. The drivetrain can, for example, be an electric drivetrain with an electric traction motor. The locking differential has a particularly small axial extent, which makes it particularly easy to integrate into the available installation space in the motor vehicle.

[0046] Further features of the invention may become apparent from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures alone, are not only in 24-2274

[0047] 12

[0048] not only in the combination specified, but also in other combinations or on its own, without leaving the scope of the invention.

[0049] The drawing shows in:

[0050] Fig. 1 shows a schematic cross-section of a locking differential in a first embodiment for a motor vehicle, wherein the locking differential is shown cut along an axial direction parallel to a rotation axis of a differential housing of the locking differential;

[0051] Fig. 2 shows a schematic sectional view of a section of the differential housing, with the differential housing shown cut perpendicular to the axial direction;

[0052] Fig. 3 shows another schematic sectional view of the locking differential in a second embodiment, wherein the differential housing is shown cut perpendicular to the axial direction;

[0053] Fig. 4 shows another schematic sectional view of the locking differential in a third embodiment, wherein the differential housing is shown cut perpendicular to the axial direction;

[0054] Fig. 5 shows a further schematic sectional view of the locking differential in a fourth embodiment, wherein the differential housing is shown cut perpendicular to the axial direction; and

[0055] Fig. 6 shows another schematic sectional view of the locking differential in a fifth embodiment, wherein the differential housing is shown cut perpendicular to the axial direction.

[0056] In the figures, identical and functionally equivalent elements are designated with the same reference symbols. 24-2274

[0057] 13

[0058] Figure 1 shows a partial cross-sectional view of a limited-slip differential 10 for a motor vehicle. The limited-slip differential 10 is designed as a differential gear with a differential lock 18. The limited-slip differential 10 comprises a differential housing 12, which is rotatable about an axis of rotation extending in the axial direction A during operation. The differential housing 12 defines a receiving space 14. Furthermore, the limited-slip differential 10 comprises two output gears 16, of which only one is partially shown in Figure 1. Each of the output gears 16 is connected to a driven wheel of the motor vehicle in a torque-transmitting manner. The output gears 16 are arranged within the receiving space 14 and are rotatable about the axis of rotation both relative to each other and relative to the differential housing 12.Furthermore, the locking differential 10 comprises at least one compensating gear arranged in the receiving space 14 (not shown in the figures), which is rotatably held on the differential housing 12 about a compensating axis fixed to the differential housing 12 by means of a compensating bolt 17 attached to the differential housing 12, the compensating bolt extending radially with its longitudinal direction. In Fig. 1, the compensating bolt 17 associated with the at least one compensating gear is schematically indicated by a dashed line. The at least one compensating gear bears against each of the output gears 16. In particular, the compensating gear is toothed with each of the output gears 16, whereby a rotational movement of one of the output gears 16 can be transmitted to the other of the output gears 16 by means of the compensating gear, or a relative rotation of the output gears 16 can be compensated for.

[0059] The limited-slip differential 10 further comprises a differential lock 18, which includes a clutch pack 20. The differential lock 18 is designed to be adjustable between a locked state and an unlocked state. In the locked state, the clutch pack 20 connects a first of the output gears 16 to the differential housing 12 in a rotationally fixed manner. In the unlocked state, the clutch pack 20 allows the first output gear 16 to rotate relative to the differential housing 12 about the axis of rotation. The clutch pack 20 comprises a plurality of clutches 22, of which first clutches 24 are rotationally fixed to the first output gear 16 and second clutches 26 are rotationally fixed to the differential housing 12. For clarity, only some of the clutches 22 are labeled with their corresponding reference numerals in Fig. 1. The first lamellae 24 and the second lamellae 26 are arranged alternately in the axial direction.The lamella package 20 is arranged in a lamella space 30, which 24-2274.

[0060] 14

[0061] The clutch pack 20 is limited at least by the differential housing 12 and, in particular, additionally by the first output gear 16. The clutch pack 20 further comprises a clutch pack end disk 28, by means of which the clutch pack 20 is closed in the axial direction on the side facing the compensating bolt 17.

[0062] Because the end disk 28 of the lamellar pack is arranged on the side of the lamellar pack 20 facing the at least one compensating bolt 17, the flow of oil 32 from the lamellar chamber 30 into the receiving chamber 14 is prevented by the end disk 28. Since the flow of oil 32 from the lamellar chamber 30 into the receiving chamber 14 is prevented by the end disk 28, efficient cooling of the lamellae 22 of the lamellar pack 20 and the gears arranged in the receiving chamber 14 requires that oil 32 be explicitly supplied to both the receiving chamber 14 and the lamellar chamber 30.

[0063] The differential lock 18 additionally comprises an actuating device, which is configured to adjust the state of the clutch pack 20. The clutch pack 20 and the actuating device are arranged on opposite sides of the at least one compensating bolt 17 of the locking differential 10 in the axial direction A. Furthermore, the clutch pack 20 radially overlaps the first output gear 16. It is also provided that the actuating device radially overlaps the second output gear (not shown in Fig. 1) in the axial direction A. Due to this design, the locking differential 10 shown in Fig. 1 has a particularly small extent in the axial direction A and is therefore particularly compact in the axial direction A.

[0064] To explicitly supply oil 32 to the clutch chamber 30, the differential housing 12 has a first oil supply channel 34. To supply oil 32 to the receiving chamber 14, the differential housing 12 has a second oil supply channel 36. The limited-slip differential 10 can have at least one pressurized oil line with at least one, in particular two, nozzles, each nozzle being directed towards one of the oil supply channels 34, 36. This means that pressurized oil from the pressurized oil line can be directed towards the first oil supply channel 34 by means of a first nozzle to cause the oil 32 to flow into the first oil supply channel 34. The second nozzle is configured to direct an oil jet towards the second oil supply channel 36 to ensure that oil flows into the second oil supply channel 34.

[0065] 15

[0066] Oil flows into oil supply channel 36 and through the second oil supply channel 36 into the receiving chamber 14.

[0067] In Fig. 2, the differential housing 12 is shown in a section, transverse to the axial direction A, which extends into the plane of the image in Fig. 2. The differential housing 12 is shown in section in the area of ​​the first oil supply channel 34. The first oil supply channel 34 has an inlet opening 38 and an outlet opening 40. The inlet opening 38 is located radially further outward than the outlet opening 40. The outlet opening 40 opens into the clutch chamber 30. The sectional view of the differential housing 12 shown in Fig. 2 corresponds to a section of the differential housing 12 along the line labeled A:A in Fig. 1.To ensure particularly precise and reliable guidance of the oil 32 via the first oil supply channel 34 into the lamellar chamber 30, it is provided that the oil 32 is sheared off by a first inlet opening edge 42, which limits the inlet opening 38 in the circumferential direction U to the rear, when the differential housing 12 is rotated about the axis of rotation in the circumferential direction U. For this purpose, the first inlet opening edge 42, as can be seen particularly well in Fig. 2, is formed by walls tapering at an acute angle. The inlet opening edge 42 is thus formed with an acute angle in the cross-section running perpendicular to the axial direction A, as shown in Fig. 2, whereby the oil 32, directed towards the inlet opening 38 in the form of an oil jet, can be scooped or sheared into the first oil supply channel 34 by means of this first inlet opening edge 42. Thus, as shown in Fig.As can be seen particularly well in Figure 2, the outlet opening 40 is offset rearward relative to the inlet opening 38 with respect to the circumferential direction U. The inlet opening edge 42 can, as indicated by the dashed line 78 in Figure 2, run obliquely rather than parallel to the axial direction A in its longitudinal direction. In a top view, it could thus be seen that the inlet opening edge 42 runs obliquely to the axial direction. This means that the inlet opening edge 42 projects to different degrees in the circumferential direction U in different length ranges arranged side by side in the axial direction A. The inlet opening edge 42 can, for example, be straight.

[0068] In the present embodiment shown in Fig. 1, it is further provided that a 24-2274 limiting the outlet opening 40 towards the compensating bolt 17

[0069] 16

[0070] The first outlet opening edge 44 of the differential housing 12 has a greater axial distance A to the compensating bolt 17 than a second inlet opening edge 46 that defines the inlet opening 38 towards the compensating bolt 17. Furthermore, it is provided that a second outlet opening edge 48, which defines the outlet opening 40 and is located opposite the first outlet opening edge 44 in axial direction A, has a greater axial distance A to the compensating bolt 17 than a third inlet opening edge 50 of the differential housing 12, which defines the side of the inlet opening 38 facing away from the compensating bolt 17 in the axial direction. The first oil supply channel 34 thus extends from the inlet opening 38 to the outlet opening 40 along the axial direction A away from the compensating bolt 17 and in the radial direction R from the outside inwards, and thus in the direction of the axis of rotation of the differential housing 12.To prevent the oil 32 from being flung out of the lamellar chamber 30 upon impact with the lamellar pack 20, contrary to the oil 32's inflow direction through the first oil supply channel 34, the lamellar chamber 30 is designed to form a radial undercut 52 towards the outlet opening 40. This allows the oil 32 to collect in this undercut 52 during operation, forming an oil pool 54. Individual, and in particular several, of the lamellars 22, especially the second lamellars 26, can project into this oil pool 54. This allows the lamellars 22 projecting into the oil pool 54 to be cooled particularly efficiently by the oil 32. As can be seen particularly well in Fig. 1, the undercut 52 is designed to deepen in the radial direction R with increasing axial distance A from the outlet opening 40.

[0071] As can be seen particularly well in Fig. 2, the outlet opening 40 is arranged further back in the circumferential direction U than the inlet opening 38. This means that a fourth inlet opening edge 56 of the differential housing 12, which limits the inlet opening 38 forward in the circumferential direction U, is arranged in the circumferential direction U in front of a third outlet opening edge 58, which limits the outlet opening 40 forward in the circumferential direction U.

[0072] To allow the oil 32 to flow out of the lamellar chamber 30, the limited-slip differential 10, in particular the differential housing 12, is provided to have at least one oil drain channel 60. As can be seen particularly well in Fig. 2, it is provided here that the oil drain channel 60 is the first 24-2274

[0073] 17

[0074] The oil supply channel 34 is partially covered to the rear in the circumferential direction U. The oil 32 can thus flow into the lamellar chamber 30 via the first oil supply channel 34, flow through the lamellar chamber 30, and flow out of the lamellar chamber 30 through the drain channel 60, in particular out of the differential housing 12. Because the drain channel 60 is arranged behind the first oil supply channel 34 in the circumferential direction U, it is offset relative to the first oil supply channel 34 in the circumferential direction U. The drain channel 60 has a drain inlet opening 62 and a drain outlet opening 64. The drain inlet opening 62 delimits the drain channel 60 towards the lamellar chamber 30. In Fig. 1, the oil draining channel 60 is indicated by dashed lines 66. As in Fig.To ensure that the oil drain inlet opening 62 can be clearly seen, it is provided here that the lamellar assembly 20 covers the lamellar assembly 20 in a circumferential section U extending along the entire axial length A of the lamellar assembly 20. This ensures that all oil 32 flowing into the lamellar chamber 30 via the at least one oil supply channel 34 can be discharged from the lamellar chamber 30 via the at least one drain channel 60. Within the lamellar chamber 30, the oil 32 can be carried along by the lamellar 22 in the circumferential direction U.

[0075] In the second embodiment shown in Fig. 3, at least some of the lamellae 22, and in particular at least some, and in particular all, of the first lamellae 24 have a radially outer indentation or recess 68, whereby a distribution channel 70 is formed by the recesses 68 of several of the lamellae 22. The distribution channel 70 extends at least partially along the axial direction A, in particular parallel to the axial direction A. Alternatively, the distribution channel 70 can extend obliquely to the axial direction A. By means of this distribution channel 70, oil 32 flowing along the lamellae 22 can be distributed in the axial direction to ensure that the oil 32 reaches all lamellae 22.This is particularly advantageous if the first oil supply channel 34 runs with its longitudinal extension direction perpendicular to the axial direction A, and thus the oil 32 flowing in the first oil supply channel 34 flows only in the radial direction R and in the circumferential direction U towards the lamellae 22. In particular, at least the first lamellae 24, as can be seen particularly well in FIGS. 3 to 5, can have several 24-2274.

[0076] 18

[0077] The tabs have radially projecting tabs R. The respective recesses 68 are arranged in particular on the respective tabs.

[0078] In the embodiment shown in Fig. 4, the first inlet opening edge 42, which limits the inlet opening 38 in the circumferential direction U to the rear, is provided by a planing element 72. In this case, this planing element 72 is a plate which is inserted into a recess in the differential housing 12. As a result, the planing element 72 does not protrude beyond that of the differential housing 12, but rather is flush with it radially outwards. As can be seen particularly well in the enlarged section in Fig. 4, the contour of the area of ​​the planing element 72 providing the first inlet opening edge 42 can be freely selected. In this case, a planing edge 74 providing the first inlet opening edge 42 is curved with its axial course about the radial direction R. The planing element 72 can also be curved about the radial direction R or be straight in the circumferential direction.

[0079] In the embodiment shown in Fig. 5, the first inlet opening edge 42, which limits the inlet opening 38 in the circumferential direction U to the rear, is provided by a vane element 76. This vane element 76 can be bonded radially to the outside of the differential housing 12. By means of the vane element 76, a particularly large amount of oil 32 can be scooped from an oil jet directed towards the inlet opening 38 into the first oil supply channel 34.

[0080] In the embodiment shown in Fig. 6, a front surface of the lamellae 22 of the lamellar pack is planar. This surface runs parallel to the flow direction in which the oil 32 flows within the first oil supply channel 34. For clarity, only some of the lamellae 22 of the lamellar pack 20 are explicitly shown in Fig. 6. As can also be seen in Fig. 6, the oil 32 is guided radially inwards through the differential housing 12 in a first section 80 of an oil path. The first section 80 is provided, at least partially, by the first oil supply channel 34. In a second section 82 of the oil path, which adjoins the first section 80 in the circumferential direction U, the oil 32 is guided radially outwards between lamellae 22 arranged side by side in the axial direction A.In the second section 82, the radial height of the lamellae 22 increases with a circumferentially increasing distance U from the first section 80. This radial design of the lamellae 22, combined with centrifugal forces acting on the oil 32, assists the oil 32, which is guided between them, in flowing circumferentially through the oil path.

[0081] In a limited-slip differential 10 with active lubrication, both the gears of the differential and the clutch pack 20 must be lubricated. Active oil injection into the limited-slip differential 10 is used to lubricate and cool the gears of the limited-slip differential 10 from the outside. Furthermore, the clutch pack 20 must be lubricated and cooled.

[0082] To minimize the installation space required for the locking differential 10, the locking differential 10 shown in Fig. 1 incorporates a transverse locking mechanism into the gearbox of the electric drive motor. This results in a particularly small axial dimension available for the locking differential 10. By directly integrating the locking differential 10 into the gearbox of the electric drive motor, the gearbox oil of the electric drive motor can be used to lubricate and cool the locking differential 10. Oil 32 with a low temperature limit can be used for this purpose. It is essential to prevent the clutch pack 20 from overheating due to active cooling with the oil 32, as this could cause the locking differential 10 or the gearbox to overheat and potentially lead to gearbox failure. Simultaneously, lubrication of the gears of the locking differential 10 must also be ensured.The oil injection velocity of the oil 32 into the first oil supply channel 34 is significantly lower than the maximum circumferential speed of the differential housing 12. It must be ensured that a required quantity of oil reaches the clutch plates 22 while simultaneously preventing the oil 32 from being flung off the plates 22 due to centrifugal force acting upon it. To meet these requirements, the oil 32 is supplied to the clutch plates 22 located in the clutch chamber 30 via the first oil supply channel 34. The use of two nozzles allows for a defined distribution of the oil 32 supplied by a pressurized oil line.For example, 70% of the supplied oil 32 can be fed into the lamellar chamber 30 via the first oil supply channel 34, and 30% of the oil 32 supplied via the pressure oil line can be fed to the wheels of the locking differential 10 arranged in the receiving chamber 14 via the second oil supply channel 32. This is achieved through the two oil supply channels 34, 36 with 20.

[0083] According to their individual guide geometries of the differential housing 12, a respective oil jet can be individually supplied to or removed from the component to be lubricated, and thus to the lamellar package 20 or the wheels arranged in the receiving space 14.

[0084] Defined slopes in the walls of the differential housing 12, which bound the first oil supply channel 34, guide the oil 32 in all three spatial directions and prevent it from escaping through the inlet opening 38 of the differential housing 12. This prevents the oil 32 from being flung off the clutch pack 20 in an uncontrolled manner. When the oil jet reaches the clutch pack 20, a tipping point can be reached at defined flow velocities. At this point, the centrifugal force acting on the oil 32 outweighs the input impulse of the pressurized oil from the pressurized oil line. If the oil 32 strikes the clutch pack 20 in axial direction A at the level of the tipping point, it would flow directly radially outwards.Therefore, by providing the undercut 52, the tipping point is geometrically set such that, upon reaching the tipping point, the oil 32 flows into the undercut 52 instead of flowing radially outwards from the differential housing 12. While the oil 32 flows in the undercut 52, it has time to dissipate heat from the clutch plates 22 and exert its lubricating effect until it can flow out of the clutch plate space 30 through the defined, at least one, draining channel 60, in particular by being flung off. The three chamfers of the walls of the differential housing 12 that bound the first oil supply channel 34 allow the oil 32 to be radially skimmed as it flows into the first oil supply channel 34 via the inlet opening 38, thus eliminating the centrifugal force acting on the oil 32 and guiding it axially in direction A into the clutch plate space 30.Further inclined surfaces of the walls of the differential housing 12, which define the first oil supply channel 34, accelerate the oil 32 in axial direction A and ensure axial delivery of the oil 32 beyond the tipping point into the lamellar chamber 30. The tipping point is defined by the second outlet opening edge 48.

[0085] To protect the oil 32 from overheating and damage, at least one defined oil drain channel 60 is provided. A path for the oil 32 through the differential housing 12 is thus defined entirely by means of the first oil supply channel 34, the clutch chamber 30, and the at least one oil drain channel 60. This allows the oil 32 to be optimally guided through the limited-slip differential 10. By varying the diameters of individual clutch plates 22 of the clutch pack 20, a particularly large wetting surface area of ​​the clutch pack 20 can be created, thereby enabling particularly efficient cooling of the clutch pack 20. In particular, it is provided that the housing-fixed second clutch plates 26 project into the oil reservoir 54. It is also possible for the first clutch plates 24, which are arranged non-rotatably to the first output gear 16, to project into the oil reservoir 54.However, there may be a conflict of objectives between having the largest possible total surface area of ​​the lamellar package 20 and the deepest possible immersion of the first lamellars 24 attached to the first output wheel 16 into the oil collection 54.

[0086] Overall, the invention demonstrates how the lubrication of a differential lock 18 in an electric drive can be implemented. Reference numerals

[0087] 10 Locking differential

[0088] 12 Differential housings

[0089] 14 Recording room

[0090] 16 first output gear

[0091] 17 compensating bolts

[0092] 18 Differential lock

[0093] 20 slat package

[0094] 22 slats

[0095] 24 first slats

[0096] 26 second slats

[0097] 28 lamellar pack end disc

[0098] 30 slat space

[0099] 32 Oil

[0100] 34 first oil supply channel

[0101] 36 second oil supply channel

[0102] 38 Inlet opening

[0103] 40 Outlet opening

[0104] 42 first inlet opening edge

[0105] 44 first outlet opening edge

[0106] 46 second inlet opening edge

[0107] 48 second outlet opening edge

[0108] 50 third inlet opening edge

[0109] 52 Undercut

[0110] 54 Oil accumulation

[0111] 56 fourth inlet opening edge

[0112] 58 third outlet opening edge

[0113] 60 Oil drain channel

[0114] 62 Oil drain inlet opening

[0115] 64 Oil drain opening

[0116] 66 dashed lines

[0117] 68 Exclusion23

[0118] 70 distribution channel

[0119] 72 Planing element

[0120] 74 Planed edge

[0121] 76 shovel element

[0122] 78 dashed line

[0123] 80 first section of the Oil Route

[0124] 82 second section of the Oil Route

[0125] A axial direction

[0126] R radial direction

[0127] U circumferential direction

Claims

Patent claims 1. Locking differential (10) for a motor vehicle, with a driveable differential housing (12) rotatable about a pivot axis, which encloses a receiving space (14), two output gears (16) which are rotatable relative to each other about the axis of rotation, which are arranged within the receiving space (17) and are rotatable relative to the differential housing (12), - at least one compensating gear (16) arranged in the receiving space (14), which is rotatably held on the differential housing (12) by means of a compensating bolt (17) attached to the differential housing (12) about a compensating axis of rotation fixed to the differential housing (12), which rests against each of the output gears (16) and is designed to transmit a rotational movement of one of the output gears (16) to the other of the output gears or to compensate for a relative rotation of the output gears (16) to each other, and a differential lock (18) comprising a lamellar package (20), which is designed to be adjusted at least between a locking state in which a first of the output gears (16) is rotationally fixed to the differential housing (12), and a release state in which the lamellar package (20) allows a relative rotation of the first output gear (16) to the differential housing (12), where the lamellar package (20) and an actuating device, which is designed to adjust the state of the lamellar package (20), are arranged on axially opposite sides (A) of the compensating bolt (17), each radially overlapping one of the compensating wheels (16), whereby the lamellar package (20) is fluidically separated from the receiving space (14) by means of a lamellar package end disk (28), and the differential housing (12) has at least one first oil supply channel with (34) an inlet opening (38) and an outlet opening (40) by means of which oil (32) can be supplied to the clutch pack (20), and25 has at least one second oil supply channel (36) by means of which oil (32) can be supplied into the receiving chamber (14).

2. Locking differential (10) according to claim 1, characterized by the fact that an edge (42) of the differential housing (12) which limits the inlet opening (38) of the first oil supply channel (34) in the direction of rotation (U) of the differential housing (12) to the rear about the axis of rotation is formed with an angle that tapers to a point in the cross-section perpendicular to the axial direction (A), whereby oil (32) of an oil jet directed towards the inlet opening (38) can be scooped into the first oil supply channel (34) by means of this edge (42).

3. Locking differential (10) according to claim 1, characterized by the fact that an edge (42) limiting the inlet opening (38) of the first oil supply channel (34) in the direction of rotation (U) of the differential housing (12) about the axis of rotation to the rear is provided by a plate-shaped planing element (72) attached to the differential housing (12) or a shovel-shaped blade element (76) attached to the differential housing (12).

4. Locking differential (10) according to one of the preceding claims, characterized by the fact that the lamellar package (20) has a distribution channel (70) which is formed by recesses (68) in several lamellae (22) of the lamellar package (20), wherein the distribution channel (70) extends at least partially in the axial direction (A) with its longitudinal direction, whereby oil (32) which has flowed to the lamellar package (20) can be guided and / or distributed in the axial direction (A) by means of the distribution channel.

5. Locking differential (10) according to one of the preceding claims, characterized by the fact that the outlet opening (40) opens into a lamellar space (30) in which the lamellar package (20) is arranged, wherein 26 a first edge (44) of the differential housing (12) limiting the outlet opening (40) towards the compensating bolt (17) has a greater distance in axial direction (A) to the compensating bolt (17) than an edge (46) of the differential housing (12) limiting the inlet opening (38) towards the compensating bolt (17), and / or a second edge (48) limiting the outlet opening (40) and opposite the first edge (44) in the axial direction (A) has a greater distance in the axial direction (A) to the compensating bolt (17) than an edge (50) of the differential housing (12) limiting the inlet opening (38) in the axial direction (A) to the side facing away from the compensating bolt (17), whereby oil (32) guided in the first oil supply channel (34) is guided axially towards the end disk of the clutch pack (28).

6. Locking differential (10) according to claim 5, characterized by the fact that the lamellar space (30) forms a radial undercut (52) to the outlet opening (40), allowing the oil (32) to collect in the undercut (52).

7. Locking differential (10) according to claim 6, characterized by the fact that The undercut (52) deepens in the radial direction (R) with increasing axial distance from the outlet opening (40).

8. Locking differential (10) according to one of the preceding claims, characterized by the fact that the locking differential (10) is designed such that the oil (32) is guided radially inwards in a first section (80) of an oil path extending in the circumferential direction (U) through the differential housing (12) and in a second section (82) of the oil path adjoining the first section (80) in the circumferential direction (U) the oil (32) is guided radially outwards between lamellae (22) arranged next to each other in the axial direction (A).

9. Locking differential (10) according to one of the preceding claims, characterized by the fact that 24-2274 27 the outlet opening (40) is located further back in the circumferential direction (II) than the inlet opening (38).

10. Locking differential (10) according to one of the preceding claims, characterized by the fact that the differential housing (12) has at least one oil draining channel (60) with an oil draining inlet opening (62) and an oil draining outlet opening (64), which is arranged in the circumferential direction (U) offset to the inlet opening (38) of the first oil supply channel (34).

11. Locking differential (10) according to claim 10, characterized by the fact that the oil drain inlet opening (62) covers the lamellar pack (20) in a circumferential section of the lamellar pack (20) over an entire length of the lamellar pack (20) extending in the axial direction (A).

12. Locking differential (10) according to one of the preceding claims, characterized by the fact that a nozzle of a pressurised oil line is aligned with the inlet opening (38) of the first oil supply channel (34), whereby oil (32) can be sprayed onto the inlet opening (38) by means of the nozzle.

13. Motor vehicle with a drive train comprising a locking differential (10) according to any of the preceding claims.

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