differential

Abstract

A differential is provided that includes a differential gear set, a split case defining a space that houses the clutch and the differential gear set, a first member of the case formed as one piece and including an end wall, a boss portion projecting axially outward from the end wall, a sidewall about an axis, and a flange extending radially outward to receive torque, the end wall having a window therethrough, a second member of the case secured with the sidewall to enclose the space, an axially movable clutch member including a branch portion that is placed in the window and that transmits torque from the end wall to the differential gear set, and an actuator having an offset axially outward from the flange and including a plunger that bears against the branch portion and is axially driven by the actuator to push the clutch member.

Description

Technical Field

[0001] The present invention relates to a differential having a clutch preferably suitable for a transmission system of a motor vehicle, and more particularly to a compact differential having sufficient rigidity. Background Technology

[0002] Since the left and right axles in a vehicle do not necessarily rotate at the same speed, it is necessary to allow differential movement between them. To transmit torque to the two axles and achieve differential movement between them, a differential is used.

[0003] For the purpose of limiting or locking differential motion, or for any other purpose, a differential may sometimes contain a clutch internally and may be combined with an external actuator for actuating the clutch. Since the clutch within the differential is rotating, while the actuator is anti-rotating, how these components should be arranged and coupled always requires some technical attention.

[0004] US8,287,417B2 discloses a differential combined with a solenoid, the solenoid serving as an actuator for actuating an internal clutch. Summary of the Invention

[0005] Of course, from the perspective of pursuing compactness, adding an actuator is inherently disadvantageous. Moreover, the inventors are more concerned about the adverse effects on stiffness caused by the structure necessary for the combination of the anti-rotation actuator and the rotational clutch, as this structure requires reinforcement and strengthening, thus increasing its size.

[0006] According to one aspect, a differential with a clutch comprises: a differential gear set configured to differentially transmit torque to a pair of output gears; a housing rotatable about an axis and defining a space sized to accommodate the clutch and the differential gear set, the housing being axially divisible into at least a first member and a second member; the first member being integrally formed and including an end wall, a boss portion projecting axially outward from the end wall, a side wall about the axis, and a flange extending radially outward to receive torque, the end wall having a window extending through the end wall; the second member being fixed to the side wall to enclose the space; a clutch member axially movable between a first position and a second position, and including a branch portion placed in the window and transmitting torque from the end wall to the differential gear set in the second position; and an actuator mounted on and coaxial with the boss portion of the first member and having an axially outward offset from the flange, the actuator having a plunger abutting against the branch portion and axially driven by the actuator to push the clutch member from the first position to the second position. Attached Figure Description

[0007] Figure 1 This is a 3D diagram of a differential.

[0008] Figure 2 This is another 3D view of the differential.

[0009] Figure 3 From Figure 4 The differential is a cross-sectional view taken from line III-III.

[0010] Figure 4 This is a side view of the differential, viewed from the end with the cover.

[0011] Figure 5 It is a sectional view of the shell drawn as an exploded view.

[0012] Figure 6 This is a side view of the annular plate.

[0013] Figure 7 This is an enlarged 3D view of the differential, which mainly shows the window and the components around it, while omitting the solenoid.

[0014] Figure 8 It is a three-dimensional view of the clutch components, the half-shaft gear that meshes with the clutch components, the annular plate, and the plunger.

[0015] Figure 9 This is an enlarged front sectional view of the differential, which mainly shows the clutch assembly and its surrounding components. Detailed Implementation

[0016] The following will refer to Figures 1 to 9 Exemplary embodiments are described. These figures are not necessarily drawn to scale, and therefore it is specifically noted that the dimensional relationships between them are not limited to those shown in the figures.

[0017] Throughout the following description and the appended claims, unless otherwise stated, axis refers to the axis of rotation of the differential and the terms “inward” and “outward” refer to “toward” and “away” from the interior of the differential housing, respectively.

[0018] The embodiments described below are for so-called "lock-up differentials" that use a clutch to lock the differential movement, but are equally applicable to so-called "free-running differentials" that use a clutch to engage / disengage the transmission of torque to the axle.

[0019] Main reference Figures 1 to 4According to the embodiment, the differential includes a housing 1 that receives torque from an engine, electric motor, etc., and thereby rotates about an axis X. The housing 1 can be axially divided into at least two components, namely a main body portion 1A and a cover portion 1B. The housing 1 also includes boss portions 45A and 45B, which are rotatably supported by a bracket (not shown). Boss portion 45A extends axially from the main body portion 1A, and boss portion 45B extends axially from the cover portion 1B.

[0020] The differential also includes a differential gear set 11 for differentially transmitting torque to a pair of half-shaft gears 23A, 23B. The housing 1 accommodates the differential gear set 11 and the clutch member 13. Clutch-suited structures, such as clutch teeth, are formed on the rear facet of the half-shaft gear 23B and the corresponding facet of the clutch member 13. Corresponding to the disengagement and engagement of this clutch, the clutch enables and disables differential movement between the half-shaft gears 23A, 23B. Simultaneously, clutch teeth are formed on the inner housing for supporting the differential gear set 11, replacing the half-shaft gears in its application to a free-running differential as described above. In this case, the clutch releases and engages the differential gear set 11 with the engine / motor.

[0021] Combination Figures 1 to 4 , refer to Figure 5 The housing 1 defines a space 47 for accommodating the gear set 11 and the clutch assembly 13. The cover portion 1B is fixed to the main body portion 1A, for example, by a plurality of bolts 41, but can be separated from the main body portion 1A to expose the space 47 to the outside when internal components are to be installed in the space 47. Although these bodies 1A, 1B can be divided around a center, for example around the pinion axis C, the dividing line is preferably away from the center. More specifically, the main body portion 1A is preferably elongated compared to the cover portion 1B. Thus, the main body portion 1A is formed in a deep bowl shape, while the cover portion 1B is formed in a shallow disc shape, so that the main body portion 1A alone supports the pinion shaft 27, which will be described later.

[0022] The main body 1A is generally, but not limited to, composed of a side wall 5 surrounding the axis X, an end wall 7 at one end, and a flange 9, which are integrally formed. The combination of the side wall 5, the end wall 7, and the cover 1B primarily defines the space 47. The flange 9 extends radially outward from the main body 1A and couples with any gear structure (e.g., a ring gear) used to receive torque.

[0023] The sidewall 5 is generally formed as a cylinder or cylindrical shape around the axis X. The sidewall 5 has an opening 49, sized to receive the pinion shaft 27. The opening 49 is radially oriented relative to the axis X and extends through the sidewall 5 from the outer to the inner part to facilitate mounting the pinion shaft 27. Notably, the sidewall 5 supports the pinion shaft 27 exclusively, while other parts of the main body 1A and the cover 1B do not support the pinion shaft 27. In other words, when the clutch is disengaged, only a limited portion from the flange 9 to the opening 49 bears the torque transmission. Other parts do not need to form a large volume for reinforcement and strengthening. This structure contributes to a reduction in the overall size of the device.

[0024] The sidewall 5 may also have a drilled hole 51 for receiving a pin for retaining the pinion shaft 27 and a bolt hole 53 for tightening a bolt 41 therein. Both preferably extend in the axial direction and open on the end face opposite the cover portion 1B. The drilled hole 51 and the bolt hole 53 are arranged alternately in the circumferential direction about the axis X, as shown from... Figure 4 This can be best understood. Bolt hole 53 is therefore in Figure 5 In the view shown perpendicular to axis X, the bolt 41 can extend beyond the opening 49 from the end face without weakening the structure around the opening 49. The head of the bolt 41 can be as follows: Figure 3 It is positioned closer to the opening 49 as shown. This helps to reduce the size, especially the lateral dimension from the shoulder of the housing 1 to the flange.

[0025] The end wall 7 is generally perpendicular to the axis X and thus forms the bottom of the bowl formed by the main body 1A. However, the end wall 7 has a drilled hole at its center and a plurality of windows 17 around the center. A boss portion 45A extending from the end wall 7 is drilled around the central hole and an axle passes through it. The windows 17 are used to couple the actuator 15 to the clutch member 13 and also to transmit torque to the clutch member 13, as described later.

[0026] Flange 9 is inherently perpendicular to axis X and extends radially outward to couple with ring gears, etc. Flange 9 is integrally formed with sidewall 5 and endwall 7 as described above. The absence of any joints within or between these portions contributes to increased strength and rigidity, and thus results in a reduction in the overall size of the device.

[0027] The flange 9 can be positioned anywhere on the sidewall 5, particularly between the opening 49 and the end wall 7, but is preferably positioned as close as possible to the end wall 7. Therefore, the end wall 7 can be positioned radially inside the flange 9 or overlap with the flange 9. The outer portion 55 of the end wall 7 can still be axially raised outward to provide sufficient thickness for the end wall 7. This structural relationship between the flange 9, the end wall 7, and its outer portion 55 improves the structural resistance to applied torque. As described later, the outer portion 55 can receive and position the actuator 15. The plane M of the outer portion 55 receiving the actuator 15 can have an axially outward offset OF from the flange plane F, which is defined as the outermost axial portion of the flange 9, such as... Figure 5 As shown.

[0028] Combination Figure 3 and Figure 5 , refer to Figure 9 The differential gear set 11 may be, but is not limited to, a helical gear type generally consisting of a pinion 29 rotatably supported by a pinion shaft 27 and a pair of half-shaft gears 23A, 23B meshing with the pinion 29. Of course, face gears or any other type are also applicable here. The pinion shaft 27 is inserted into the opening 49 and secured to the side wall 5 by a pin 27P inserted laterally therein. The pinion shaft 27 receives torque about the axis X, and the pinion 29, rotatable about the pinion axis C, transmits the torque to the half-shaft gears 23A, 23B. The differential gear set 11 thus differentially transmits the applied torque to the half-shaft gears 23A, 23B, thereby allowing differential movement between them.

[0029] Each axle gear 23A, 23B is a hollow gear formed to mesh with a pinion 29, having a splined or any structure for coupling with an axle. The axle gear 23A on the flange 9 side has an engagement structure, such as pawl teeth, for meshing with the clutch member 13. The clutch, consisting of the axle gear 23A and the clutch member 13, restricts differential movement between the axle gears 23A, 23B in the engaged state.

[0030] For example, combining Figure 3 and Figure 9 , refer to Figure 8 The clutch member 13 is generally formed as a slightly larger ring. The clutch member 13 has multiple axially outwardly projecting branch portions 13L corresponding to the window 17, and on the opposite face, any engaging structure corresponding to the half-shaft gear 23A, such as pawl teeth. When the clutch member 13 is held between the end wall 7 and the half-shaft gear 23A, some axial movement is permitted to engage and disengage with the half-shaft gear 23A.

[0031] The branch portions 13L are located in the window 17, and these ends are exposed to the outside of the port 7 through the window 17. The dimensions of each side portion 13S of the branch portion 13L are set to abut against the side portion 17S of the window 17. Therefore, when the clutch is engaged, the clutch member 13 receives torque from the end wall 7 and transmits the torque to the half-shaft gear 23A.

[0032] The actuator 15 can be any drive device formed in a cylindrical shape, such as a solenoid, hydraulic cylinder, pneumatic cylinder, or motor cylinder, which axially pushes the end of the branch portion 13L exposed through the window 17. In the case of a solenoid, the actuator 15 includes, for example, an electromagnetic coil 31 and a core 33 for guiding the magnetic flux generated by the coil 31, the electromagnetic coil 31 having a cable 31L leading out therefrom.

[0033] The actuator 15 may include a cylindrical plunger 21 for transmitting its driving force to the clutch member 13, while the actuator 15 itself moves axially to actuate the clutch member 13. The differential may include a repulsive element (e.g., a spring) for returning the clutch to the disengaged state, for example, the repulsive element may be repulsively inserted between the half-shaft gear 23A and the clutch member 13. Of course, the actuator 15 may also be used to pull the clutch member 13, and the repulsive element may be used to engage the clutch.

[0034] In the case where the actuator 15 is a solenoid, in order to prevent magnetic flux leakage, the plunger 21 can generally be made of any non-magnetic material such as stainless steel, any aluminum alloy or any engineering plastic, but may also include a magnetic part 37 made of any magnetic material such as low carbon steel, which is arranged to face the electromagnetic coil so as to be driven by the solenoid magnetic force.

[0035] The actuator 15 is positioned close to or in contact with the outer portion 55 of the end wall 7 and coaxial with the boss portion 45A. The actuator 15 thus has an axial outward offset relative to the flange 9, which corresponds to the offset OF of the outer portion 55. Preferably, the actuator 15 is slidably mounted on the boss portion 45A. Because the actuator 15 is positioned in this way, the size of the differential can be reduced.

[0036] Combination Figure 1 , Figure 3 and Figures 7 to 9 , refer to Figure 6 The differential also includes an annular plate 19 for detecting whether the clutch is engaged or disengaged. The annular plate 19 is generally a ring coaxial with the X-axis and has multiple, for example three, tab portions 19T for attachment to the branch portion 13L. The tab portions 19T are attached to the branch portion 13L respectively by bolts 43, rivets, or any other fixing means. Alternatively, the tab portions 19T can be attached to the plunger 21.

[0037] The outer surface 55 of the end wall 7 may be flat, at least within the area where the actuator 15 contacts it, and the end wall 7 may include a notch 57 through which the tab portion 19T is led out, such as... Figure 7 As shown in the optimal diagram. However, since the notches 57 are narrow enough, they have almost no adverse effect on the structural stiffness against the applied torque.

[0038] The notch 57 provides sufficient clearance to allow the contact plate portion 19T to move axially, thus following the movement of the clutch member 13. Therefore, when the annular plate 19 indicates the position of the clutch member 13 externally, the clutch's engagement or disengagement can be detected externally. Similarly, since the annular plate 19 rotates together with the differential, it can also be used for speed detection.

[0039] As can be easily understood from the above description, the torque input through flange 9 propagates only within a limited area of ​​housing 1. The torque flow can be represented by two paths. In the first path, which is typically established in the disconnected state, the torque is transmitted from flange 9 through a limited portion of sidewall 5 to pinion shaft 27. In the second path, which is established only in the connected state, the torque is also delivered from flange 9 through endwall 7 to clutch member 13. Since cover portion 1B and bolt 41 are stably located outside these paths, these components can be reduced in size without loss of structural strength and stiffness. Furthermore, the second path, while compact, can have sufficient torsional stiffness, primarily due to the specific relationship between flange 9, endwall 7, and its outer surface 55 as described above.

[0040] Although some exemplary embodiments have been described above, those skilled in the art will make modifications and variations to the embodiments based on the above teachings.

Claims

1. A differential with a clutch, comprising: A differential gear set, which is configured to transmit torque differentially to a pair of output gears; A housing that is rotatable about an axis and has dimensions configured to accommodate the clutch and the differential gear set, the housing being axially divisible into at least a first component and a second component; The first component is integrally formed and includes an end wall, a boss portion projecting axially outward from the end wall, a side wall surrounding the axis, and a flange extending radially outward to receive the torque. The end wall has a window penetrating the end wall, and the side wall includes an opening for receiving the pinion shaft of the differential gear set. The second component is fixed to the sidewall to enclose the space; A clutch component, axially movable between a first position and a second position, and including a branch portion placed in the window and transmitting the torque from the end wall to the differential gear set in the second position; as well as An actuator, mounted on and coaxial with the boss portion of the first member and having an axially outward offset from the flange, the actuator having a plunger abutting against the branch portion and axially driven by the actuator to push the clutch member from the first position to the second position. The end wall is located radially inside the flange or overlaps with the flange, and includes an outer portion that protrudes axially outward from the flange and receives the actuator. The flange is disposed between the opening on the side wall and the end wall.

2. The differential according to claim 1, wherein, The end wall is at least partially in contact with the actuator and includes a notch to leave a gap between the end wall and the actuator.

3. The differential according to claim 2, further comprising: An annular plate, which is fixed to the branch portion to follow the movement of the clutch component and is led out through the gap.

4. The differential according to claim 1, wherein, The actuator is slidably mounted on the boss portion of the first component.

5. The differential according to claim 1, wherein, The actuator includes a solenoid configured to magnetically drive the plunger.

6. The differential according to claim 1, wherein, The flange overlaps axially with the clutch component.

Images