Differential with disconnect

Abstract

A differential (10) is provided. The differential (10) includes a cage (30), a carrier (40), and a disconnect coupling (50) having radially projecting splines (56a-b) configured to selectively connect the carrier (40) to the cage (30).

Description

[Technical Field]

[0001] The present invention relates to differential devices, and in particular to solutions for decoupling the rotating components of a differential from the driveline. [Background technology]

[0002] A differential, typically located on an axle, allows the wheels to rotate at different speeds. The differential has a ring gear that receives an input drive torque, causing the ring gear to rotate. The ring gear is connected to a carrier that surrounds planetary bevel gears, which engage driven bevel gears attached to each wheel axle. The planetary bevel gears can rotate about their respective axes, allowing differential motion of the driven bevel gears.

[0003] It has been proposed to include a disconnect functionality in the differential to disengage the driven bevel gears (i.e., each wheel) from the transverse ring gear. One such example is described in WO2020178875, in which the ring gear is connected to an outer case. An inner case, which forms a carrier together with the planetary gears and driven bevel gear, is connectable to the outer case by a clutch. The clutch is formed by a cylindrical member that is axially movable relative to the outer case and has axially upstanding teeth that face and mate with axially disposed teeth on the inner case. Engaging the clutch causes the cylindrical member to move axially, engaging the dog teeth, thereby connecting the ring gear to the inner case via the outer case.

[0004] While this prior art document suggests a solution that provides the desired differential disconnect function, the axial engagement / disengagement of the dog teeth creates significant and disruptive noise. Therefore, there is a need for an improved differential with disconnect function that provides smoother operation and reduces undesirable sounds. Summary of the Invention

[0005] It is an object of the present invention to at least partially overcome one or more of the above limitations of the prior art.

[0006] According to a first aspect, a differential is provided. The differential includes a cage, a carrier, and a disconnect coupling having radially projecting splines configured to selectively connect the carrier to the cage.

[0007] The radially projecting splines may be disposed on an axially movable dog member.

[0008] The radially projecting splines may be arranged in at least two parallel rows.

[0009] The radially projecting splines may be disposed on a first side of the dog member, and the dog member may include a second set of splines on a second side.

[0010] The radially projecting splines may face the carrier and be configured to selectively engage mating splines on the carrier.

[0011] The second set of splines on the dog members may be in constant engagement with mating splines on the cage.

[0012] The dog members may be rigidly attached to the controllable sleeve.

[0013] According to a second aspect, a differential is provided, the differential including a cage, a carrier, and a disconnect joint having a dog member radially disposed between the carrier and the cage.

[0014] The dog members may be provided with radially projecting splines configured to selectively connect the carrier to the cage.

[0015] According to a third aspect, there is provided a vehicle, the vehicle comprising a differential according to the first or second aspect. [Brief explanation of the drawings]

[0016] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which: [Figure 1] FIG. 1 is a cross-sectional view of a differential according to one embodiment. [Figure 2a] FIG. 2a is a partial cross-sectional view showing the differential of FIG. 1 in a connected mode. [Figure 2b] FIG. 2b is a partial cross-sectional view showing the differential of FIG. 1 in a connected mode. [Figure 3a] FIG. 3a is a partial cross-sectional view showing the differential of FIG. 1 in a disengaged mode. [Figure 3b] FIG. 3b is a partial cross-sectional view showing the differential of FIG. 1 in a disengaged mode. [Figure 4a] FIG. 4a is an enlarged cross-sectional view of a portion of the differential of FIG. [Figure 4b] FIG. 4b is an enlarged cross-sectional view of a portion of the differential of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] 1, a differential 10 is shown in cross section. The differential 10 includes a ring gear 20 that is fixedly secured to a differential cage 30, for example, by bolts 21. While the ring gear 20 is shown as having radial gears 22, it should be noted that the ring gear 20 could also include bevel gears. The ring gear 20 is configured to receive input torque from a torque source, for example, an electric motor (not shown).

[0018] The differential cage 30 surrounds a carrier 40. The carrier 40 has a cylindrical extension and two opposing planetary bevel gears 42, 44. The planetary bevel gears 42, 44 are connected to the carrier 40 by a pin 46 that extends through the carrier 40.

[0019] The planetary bevel gears 42, 44 are engaged with two opposing driven bevel gears 48, 49. Each of the driven bevel gears 48, 49 is connected to a respective wheel axle (not shown).

[0020] The carrier 40 is selectively connected to the differential cage 30 by a disconnect coupling 50. The disconnect coupling 50 includes an axially displaceable sleeve 52 disposed radially outward of the differential cage 30. The disconnect coupling 50 further includes cylindrical dog members 54 secured to the sleeve 52 such that axial movement of the sleeve 52 causes corresponding axial movement of the dog members 54.

[0021] An actuator (not shown) is provided to control the disconnect device 50. Preferably, the actuator is an electromechanical actuator having an eccentric pin inserted into a slot in the sleeve 52. Upon actuation, the actuator rotates the pin, thereby also moving the pin axially due to the eccentric configuration. Thus, maximum translation of the sleeve 52 can be achieved by rotating the pin by no more than ±90°.

[0022] However, it should be noted that other actuators may replace the above example utilizing an eccentric pin, and a ball ramp mechanism or a hydraulic piston could be considered as possible options for controlling the disconnect device 50.

[0023] Dog members 54 are radially disposed between carrier 40 and cage 30. Dog members 54 have external splines 55 that engage mating splines 31 on the inner surface of cage 30.

[0024] The dog member 54 is further provided with internal splines 56a-b that selectively engage with the mating external splines 41a-b of the carrier 40.

[0025] 2a-b, the differential 10 is shown with the disconnect joint 50 engaged, ie, with the carrier 40 rotatably connected to the cage 30. As shown in FIG.

[0026] 2a shows the outer surface of dog member 54. External splines 55 have an axial extension that exceeds the maximum axial distance that dog member 54 can travel. Thus, the splines 55 that project radially from dog member 54 will always engage internal splines 31 of cage 30.

[0027] 2b shows the outer surface of carrier 40. Two rows of splines 41a-b are disposed on the side ends of carrier 40. Splines 41a-b project radially and engage with corresponding inner rows of splines 56a-b on dog member 54.

[0028] 3a-b, the differential 10 is shown with the disconnect joint 50 disengaged, ie, the carrier 40 is free to rotate relative to the cage 30. As shown in FIG.

[0029] In Figure 3a, the outer surface of the dog member 54 is shown, i.e., this view corresponds to Figure 2a, but the sleeve 52 and dog member 54 have been moved axially to the right. The external splines 55 of the dog member 54 are still in engagement with the internal splines 31 of the cage 30.

[0030] Figure 3b shows the outer surface of carrier 40; i.e., this view corresponds to Figure 3a, but sleeve 52 and dog member 54 have been moved axially to the right. Two rows of splines 56a-b have been displaced axially so that they no longer engage with outer splines 41a-b of carrier 40.

[0031] Cross-sectional views of disconnect coupling 50 are shown in Figures 4a-b (given by). As can be seen from Figure 4a, which shows the connected state of disconnect coupling 50, sleeve 52 has been moved to the left and has reached its end position, which corresponds to the position of dog member 54 in which rows of splines 56a-b are engaged with rows of splines 41a-b of carrier 40.

[0032] In FIG. 4b, sleeve 52 is moved to the right to reach its opposite end position, which corresponds to the position of dog member 54 where spline rows 56a-b are moved axially out of contact with spline rows 41a-b of carrier 40.

[0033] While the present invention has been described with reference to the specific examples shown in the drawings, it should be noted that in some embodiments, it is possible to arrange the splines 55, 56a-b of the dog member 54 in the opposite manner, i.e., so that the dog member 54 is always connected with the carrier 40 and instead a selective connection is established with the cage 30. Such an arrangement would require the outer spline arrangement of the carrier to be relocated to the inner side of the cage 30, or vice versa.

[0034] From the foregoing description, while various embodiments of the present invention have been described and illustrated, the present invention is not limited thereto and may be embodied in other ways within the subject matter defined in the following claims.

Claims

1. A differential (10) comprising a cage (30), a carrier (40), and a disconnect coupling (50) having radially projecting splines (56a-b) configured to selectively connect the carrier (40) to the cage (30).

2. The differential (10) of claim 1, wherein the radially projecting splines (56a-b) are disposed on axially movable dog members (54).

3. The differential (10) of claim 2, wherein the radially projecting splines (56a-b) are arranged in at least two parallel rows.

4. 4. The differential (10) of claim 2 or 3, wherein the radially protruding splines (56a-b) are disposed on a first side of the dog member (54), the dog member (54) further comprising a second set of splines (55) on a second side.

5. 5. The differential (10) of claim 4, wherein the radially protruding splines (56a-b) face the carrier (40) and are configured to selectively engage with mating splines (41a-b) of the carrier (40).

6. 6. The differential (10) of claim 4 or 5, wherein the second set of splines (55) of the dog members (54) are in constant engagement with mating splines (31) of the cage (30).

7. The differential (10) of any one of claims 2 to 6, wherein the dog members (54) are rigidly attached to the controllable sleeves (52).

8. A differential (10) comprising a cage (30), a carrier (40), and a disconnect joint (50) having a dog member (54) radially disposed between the carrier (40) and the cage (30).

9. 9. The differential (10) of claim 8, wherein the dog members (54) include radially projecting splines (56a-b) configured to selectively connect the carrier (40) to the cage (30).

10. A vehicle comprising a differential (10) according to any one of claims 1 to 9.

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