JP7491690B2 - Differential device - Google Patents

Description

The present invention relates to the technical field of differential devices that are installed in vehicles and perform differential motion while the vehicle is running.

Vehicles such as automobiles are provided with a power transmission device for transmitting the power of an engine, electric motor, etc. to the drive wheels, and the power output from the power transmission device is transmitted to the drive wheels via a differential device.

The differential device has a differential mechanism arranged inside the housing, which is composed of a ring gear, a differential case, side gears, and a pinion gear. Inside the housing are arranged a drive shaft to which power is transmitted and a drive gear fixed to one end of the drive shaft, and the drive gear is meshed with the ring gear.

When the vehicle is traveling straight, the resistance from the road surface to the left and right drive wheels is equal, so the differential case, which rotates together with the ring gear, revolves the pinion gear, and the rotational force of the pinion gear is transmitted to the left and right side gears that are meshed with the pinion gear. At this time, the side gears revolve without rotating.

On the other hand, when the vehicle turns, the resistance from the road surface to the left and right drive wheels is different, and one side gear tries to push back against the pinion gear, causing the pinion gear to revolve and rotate. Therefore, the rotation of the pinion gear increases the rotation speed of the other side gear, creating a rotation difference between the left and right drive wheels and ensuring smooth driving conditions.

Some differential devices as described above are equipped with a mechanism that performs a different function in addition to the differential mechanism that performs the differential when the resistance from the road surface to the left and right drive wheels is different (for example, see Patent Document 1). The differential device described in Patent Document 1 is added with a function to connect (4WD state) and disconnect (2WD state) the engine side and the differential mechanism, and a function to lock and unlock the differential rotation.

Some differential devices incorporate a differential limiting mechanism that limits the differential operation of the differential mechanism in addition to the differential mechanism, thereby achieving high driving performance (see, for example, Patent Documents 2 and 3). Such a differential limiting mechanism is called a limited slip differential (LSD), and LSDs include both mechanically operated and electronically operated types.

For example, when driving sports cars around sharp curves at high speeds, if the inside drive wheel is lifted into the air by centrifugal force and the differential mechanism distributes the driving force to the inside drive wheel, the inside drive wheel will spin freely and the outside drive wheel, which is on the ground, will not rotate, which could result in a drop in speed when cornering or difficulty in escaping from rough roads.

Therefore, the differential limiting mechanism limits the operation of the differential mechanism and suppresses spinning of the drive wheels, improving the above-mentioned phenomenon while driving and achieving high driving performance.

Japanese Patent Application Laid-Open No. 11-210863 JP 2001-323988 A JP 2019-23480 A

However, in differential devices with functions other than the differential function described in Patent Documents 1 and 2, the additional mechanisms for performing the other functions tend to increase in size.

For example, if such an added mechanism is placed externally on either the left or right side of the differential mechanism, it may be prone to interfere with other structures such as fuel piping, which may necessitate a change in design. Even if the added mechanism is built into the housing that also houses the differential mechanism, various parts such as the motor will protrude and may still interfere with other structures.

Therefore, the present invention aims to improve functionality while avoiding large size.

First, a differential device according to the present invention comprises a differential case rotated by power transmitted through a drive gear, a pinion shaft having a gear portion and capable of rotating relative to the differential case, a pinion gear that rotates integrally with the pinion shaft and revolves with the rotation of the differential case, a side gear that meshes with the pinion gear and transmits power from the drive gear to an axle, a rotating body that has a transmission gear portion meshed with the gear portion and rotates while meshing with the gear portion of the pinion shaft, and a differential limiting mechanism that applies a rotational load to the pinion shaft via the rotating body, wherein the rotating body is capable of rotating at a speed different from that of the pinion shaft, a clutch mechanism is provided in the differential limiting mechanism, a coil for operating the clutch mechanism is provided in the differential limiting mechanism, and the coil and the rotating body are positioned apart in the direction of the rotation axis of the differential case .

As a result, a rotational load is applied to the pinion shaft via the rotor meshed with the gear portion of the transmission gear unit, so that the rotor is positioned close to the pinion shaft and the differential limiting mechanism is positioned close to the rotor. Also, it becomes possible to control the magnitude of the rotational load applied to the pinion shaft by the operating state of the versatile clutch mechanism.

Secondly, in the differential device according to the present invention described above, it is desirable that the rotating body be positioned around the differential case.

As a result, the differential case and the rotor are positioned side-by-side in the radial direction of the axle, so the rotor does not protrude beyond the differential case in the axial direction of the axle.

Thirdly, in the differential device according to the present invention described above, it is desirable that the rotation axis of the differential case and the rotation axis of the rotor are aligned.

This makes it possible to minimize the radial distance between the differential case and the rotors on the axle.

Fourthly, in the differential device according to the present invention described above, it is desirable that the differential limiting mechanism be positioned around the differential case.

As a result, the differential case and the limited slip differential mechanism are positioned side-by-side in the radial direction of the axle, so the limited slip differential mechanism does not protrude beyond the differential case in the axial direction of the axle.

In the differential device according to the present invention described above , it is preferable that the differential case, the pinion shaft, the pinion gear, the side gear, the rotor, and the limited slip differential mechanism are disposed inside a housing.

This allows the differential case, pinion shaft, pinion gear, side gear, rotor, and limited slip differential mechanism to be housed within the same housing.

In the differential device of the present invention described above , it is desirable that the rotating body be positioned between the pinion shaft and the differential limiting mechanism in the axial direction of the rotating shaft in the differential case, and that a regulating unit that regulates displacement of the rotating body toward the differential limiting mechanism be attached to the differential case.

As a result, the restricting portion restricts the displacement of the rotating body toward the differential limiting mechanism.

According to the present invention, the transmission gear section is configured so that a rotational load is applied to the pinion shaft via a rotating body that is meshed with the gear section, so that the rotating body is positioned close to the pinion shaft and the differential limiting mechanism is positioned close to the rotating body, improving functionality while avoiding size increases.

2 to 4 show an embodiment of a differential device according to the present invention, and this figure shows a schematic configuration of a vehicle. FIG. FIG. 4 is an enlarged cross-sectional view showing a state in which the differential limiting mechanism is not in operation. FIG. 4 is an enlarged cross-sectional view showing a state in which the differential limiting mechanism is operated.

Below, we will explain the embodiment of the differential device of the present invention with reference to the attached drawings.

<Vehicle configuration>
First, an outline of the configuration of a vehicle 100 equipped with a differential device will be described (see FIG. 1).

The vehicle 100 is equipped with an engine 101, a power transmission device 102, a hydraulic control unit 103, a gear mechanism 104, a differential device 1, driving wheels 105, 105, an engine control unit 106, a transmission mechanism control unit 107, and a bus 108.

The engine 101 functions as a power source (prime mover) for propelling the vehicle 100, consuming fuel to generate power that acts on the drive wheels 105, 105 of the vehicle 100. The engine 101 burns fuel to generate torque in a crankshaft 109 that functions as an output shaft to the power transmission device 102. Note that in the vehicle 100, an electric motor may be provided as a drive source for propelling instead of or in addition to the engine 101.

The power transmission device 102 has a torque converter 110, a forward/reverse switching mechanism 111, and a speed change transmission mechanism 112. The power transmission device 102 is provided in the path of power transmission from the engine 101 to the drive wheels 105, 105, has the function of transmitting power from the engine 101 to the drive wheels 105, 105, and operates by the hydraulic pressure of the hydraulic oil.

The torque converter 110 is disposed between the engine 101 and the forward/reverse switching mechanism 111, and has the function of amplifying or maintaining the torque of the power transmitted from the engine 101 via the crankshaft 109 and transmitting it to the forward/reverse switching mechanism 111.

The forward/reverse switching mechanism 111 is disposed between the torque converter 110 and the speed change transmission mechanism 112, and has the function of changing the rotational speed of the rotating shaft rotated by the power transmitted from the engine 101 via the torque converter 110, and the function of switching the rotational direction of the rotating shaft.

The speed change transmission mechanism 112 is disposed between the forward/reverse switching mechanism 111 and the gear mechanism 104. Power is transmitted from the forward/reverse switching mechanism 111 to the speed change transmission mechanism 112 via an input shaft 113, and the power input from the speed change transmission mechanism 112 via the input shaft 113 is output toward the gear mechanism 104 via an output shaft 114. The speed change transmission mechanism 112 has a continuously variable transmission (Continuously Variable Transmission (CVT)) that continuously changes the speed of the power input via the input shaft 113.

The power transmitted from the speed change transmission mechanism 112 to the output shaft 114 is transmitted to the differential device 1 via the gear mechanism 104. The differential device 1 transmits the transmitted power to the drive wheels 105, 105 via the axles 115, 115. The differential device 1 has the function of absorbing the difference in rotational speed between the drive wheels 105, 105 that occurs when the vehicle 100 turns.

The hydraulic control unit 103 operates the torque converter 110, forward/reverse switching mechanism 111, and speed change transmission mechanism 112 using the hydraulic oil pressure. The hydraulic control unit 103 is provided with multiple oil passages, oil reservoirs, oil pumps, multiple solenoid valves, etc. (not shown), and controls the flow rate and hydraulic pressure of the hydraulic oil supplied to each part of the power transmission device 102 based on a control signal output from the transmission mechanism control unit 107. The hydraulic control unit 103 also functions as a lubricating oil supply unit that lubricates each part of the power transmission device 102 and each part of the differential device 1.

The engine control unit 106 and the transmission mechanism control unit 107 are equipped with a microcomputer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and are connected to each other so that data communication between them is possible via a bus 108 that supports a specific in-vehicle network communication standard such as CAN (Controller Area Network).

The engine control unit 106 has the function of performing various operational controls for the engine 101, such as fuel injection control, ignition control, and intake air volume adjustment control. The engine control unit 106 is capable of communicating with the transmission mechanism control unit 107, and outputs data regarding the operating state of the engine 101 to the transmission mechanism control unit 107 as necessary, and also performs operational control of the engine 101 based on various signals output from the transmission mechanism control unit 107 as necessary.

The transmission mechanism control unit 107 controls the hydraulic control unit 103 to control the operation of the torque converter 110, the forward/reverse switching mechanism 111, and the speed change transmission mechanism 112.

<Differential device configuration>
Next, the configuration of the differential device 1 will be described (see FIGS. 2 and 3).

The differential device 1 is constructed with the necessary parts arranged or supported in the housing 2.

The housing 2 has a cylindrical shaft support portion 3 extending forward and backward, and a cover portion 4 connected to the rear end of the shaft support portion 3, with the internal space of the cover portion 4 being formed as the arrangement space 4a. Openings 4b, 4b are formed on the left and right sides of the cover portion 4, and the openings 4b, 4b are connected to the arrangement space 4a. A power outlet hole 4c is formed in the cover portion 4.

Shaft connecting members 5, 5 are inserted into the arrangement space 4a of the cover part 4 through openings 4b, 4b, respectively. An axle 115 is connected to the shaft connecting member 5.

The drive shaft 6 is rotatably supported on the shaft support portion 3 of the housing 2. Power is transmitted to the drive shaft 6 from the engine 101 etc. via a gear mechanism 104.

A drive gear 7 is fixed to the rear end of the drive shaft 6. The drive gear 7 is positioned in the arrangement space 4a of the cover part 4 and rotates together with the drive shaft 6.

A differential mechanism 8 is arranged in the arrangement space 4a of the cover portion 4. The differential mechanism 8 has a ring gear 9, a differential case 10, pinion shafts 11, 11, pinion gears 12, 12, and side gears 13, 13.

The ring gear 9 has an axial direction oriented in the left-right direction and is meshed with the drive gear 7. The ring gear 9 is fixed to the differential case 10. Therefore, the ring gear 9 and the differential case 10 rotate together.

The differential case 10 has a gear arrangement section 14 in which pinion gears 12, 12 and side gears 13, 13 are arranged, and shaft insertion sections 15, 16 that protrude from the gear arrangement section 14 on both the left and right sides, with the shaft insertion section 16 being longer in the left-right direction than the shaft insertion section 15. The gear arrangement section 14 has shaft support holes 14a, 14a that penetrate from front to back and are formed at a distance from each other in the front to back. Gear support holes 14b, 14b are formed at the connecting parts of the gear arrangement section 14 with the shaft insertion sections 15, 16. Shaft connecting members 5, 5 are inserted into the shaft insertion sections 15, 16, respectively.

The differential case 10 is rotatably supported on the cover part 4 of the housing 2 via roller bearings 17, 17, and the axial direction of the rotating shaft 10a is oriented in the left-right direction.

A gear connecting tube 18 is rotatably arranged inside the gear arrangement section 14. The gear connecting tube 18 has an axial direction in the front-rear direction and is positioned between the shaft support holes 14a, 14a.

The pinion shafts 11, 11 are rotatably supported by the gear arrangement section 14 with a portion of each inserted into the shaft support hole 14a, 14a. The pinion shaft 11 consists of a shaft-shaped section 11a extending forward and backward, and a gear section 11b protruding from one end of the shaft-shaped section 11a in the axial direction. A portion of the shaft-shaped section 11a on the gear section 11b side is inserted into the shaft support hole 14a, and the end of the shaft-shaped section 11a opposite the gear section 11b is connected to the gear connecting tube 18. Therefore, the pinion shafts 11, 11 rotate integrally with the gear connecting tube 18 relative to the differential case 10.

The pinion gears 12 are each supported by a spline engagement on the shaft portion 11a of the pinion shaft 11 and positioned inside the gear arrangement portion 14. Therefore, the pinion gears 12 rotate integrally with the pinion shaft 11.

The side gear 13 is rotatably supported by the gear arrangement section 14 with a portion of it inserted into the gear support hole 14b, and is meshed with both of the pinion gears 12, 12. One end of the shaft connecting members 5, 5 inserted into the shaft insertion sections 15, 16 is connected to the side gears 13, 13. Therefore, the side gears 13, 13 rotate integrally with the shaft connecting members 5, 5 relative to the differential case 10.

The differential device 1 is provided with a differential limiting mechanism 19 that limits the function of the differential mechanism 8. The differential limiting mechanism 19 is a mechanism added to the differential mechanism 8 in order to obtain higher driving performance of the vehicle 100, and is called a limited slip differential (LSD).

The differential limiting mechanism 19 is disposed on the outer periphery of the differential case 10 in the arrangement space 4a of the cover portion 4 in the housing 2. The differential limiting mechanism 19 is controlled by an electronic control unit (ECU) (not shown) having, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and is operated by supplying current to a coil (described later) based on a drive signal sent from the electronic control unit.

The electronic control unit sends a drive signal to the differential limiting mechanism 19 at a level corresponding to, for example, the acceleration of the vehicle 100, and the differential limiting mechanism 19 limits the operating state of the differential mechanism 8.

The differential limiting mechanism 19 has a coil (electromagnetic solenoid) 20, a control cam 21, a control clutch 22, a main cam 23, a main clutch 24, and an armature 25, and is disposed on the outer periphery of the shaft insertion portion 16 in the differential case 10.

The coil 20 is disposed inside the gear arrangement section 14 at a position toward one end in the left-right direction and is held by a coil holder 26. The power outlet hole 4c of the cover section 4 is located on the outer periphery of the coil holder 26, and an electric wire (not shown) that is inserted through the power outlet hole 4c is connected to the coil 20. The coil holder 26 is formed from a magnetic metal material. A current is supplied to the coil 20 based on a drive signal sent from an electronic control unit.

The coil 20 is covered by the clutch holder 27 from the gear arrangement portion 14 side. The clutch holder 27 has an outer portion 27a, an inner portion 27b, an outer peripheral surface portion 27c, and a press-fit member 27d. The outer portion 27a, the inner portion 27b, and the outer peripheral surface portion 27c are all formed from a magnetic metal material, and the press-fit member 27d is formed from a non-magnetic material. The inner portion 27b is positioned on the inner peripheral side of the outer portion 27a, and the press-fit member 27d is press-fitted between the outer portion 27a and the inner portion 27b. The outer peripheral surface portion 27c protrudes laterally from the outer end of the outer portion 27a.

Since the coil holder 26, the outer portion 27a, the inner portion 27b, and the outer peripheral portion 27c are made of a magnetic metal material, when a current is supplied to the coil 20 based on a drive signal sent from the electronic control unit, a magnetic field is generated around the coil 20.

The clutch holder 27 is supported by the shaft insertion portion 16 of the differential case 10 through a spline fit, and is made rotatable relative to the coil holder 26 via a ball bearing 28. Therefore, the clutch holder 27 rotates integrally with the differential case 10 relative to the coil holder 26.

The control cam 21 is positioned to the side of the inner portion 27b of the clutch holder 27 and is rotatable relative to the differential case 10. A recess 21a is formed on one of the left and right sides of the control cam 21. The recess 21a of the control cam 21 has an inclined surface (not shown) whose depth changes in the circumferential direction.

The control clutch 22 is composed of multiple outer friction plates 22a and multiple inner friction plates 22b arranged alternately in the left-right direction. The outer periphery of the outer friction plates 22a is supported by the outer periphery surface portion 27c, and is rotated integrally with the clutch holder 27 and is movable in the left-right direction relative to the clutch holder 27. The inner periphery of the inner friction plates 22b is supported by the outer periphery of the control cam 21, and is rotated integrally with the control cam 21 and is movable in the left-right direction relative to the control cam 21.

The control clutch 22 has the function of transmitting power between the control cam 21 and the clutch holder 27 by the outer friction plate 22a and the inner friction plate 22b approaching each other and engaging or slipping. In the control clutch 22, the magnitude of the power transmitted between the control cam 21 and the outer peripheral surface portion 27c is changed according to the magnitude of the friction force between the outer friction plate 22a and the inner friction plate 22b.

The main cam 23 is positioned to the side of the control cam 21, facing the control cam 21, and is rotatable relative to the differential case 10. A recess 23a is formed on the surface of the main cam 23 facing the control cam 21. The recess 23a of the main cam 23 has an inclined surface whose depth changes in the circumferential direction.

A number of balls 29 are arranged circumferentially spaced apart between the control cam 21 and the main cam 23. The balls 29 are inserted and held in the recesses 21a of the control cam 21 and the recesses 23a of the main cam 23.

The rotating body 30 is disposed on the opposite side of the control cam 21 with the main cam 23 in between in the left-right direction. The rotating body 30 is rotatable relative to the differential case 10 via a bearing 31, and the axial direction of the rotating shaft 30a is in the left-right direction. The rotating shaft 30a of the rotating body 30 and the rotating shaft 10a of the differential case 10 are aligned.

By aligning the rotation axis 10a of the differential case 10 and the rotation axis 30a of the rotor 30 in this way, it is possible to minimize the distance between the differential case 10 and the rotor 30 in the radial direction of the axle 115, thereby making it possible to miniaturize the differential device 1.

The rotating body 30 is formed in a cylindrical shape and is positioned on the outer periphery of the portion of the differential case 10 that extends from the gear arrangement portion 14 to the shaft insertion portion 16. The rotating body 30 is provided with a transmission gear portion 30b at the end of the rotating body 30 on the gear arrangement portion 14 side in the axial direction, and the transmission gear portion 30b is meshed with the gear portions 11b, 11b of the pinion shafts 11, 11. Therefore, the rotating body 30 is rotatable in conjunction with the rotation of the pinion shafts 11, 11, and when the rotation of the rotating body 30 is controlled, the rotation of the pinion shafts 11, 11 is also controlled.

A part of the main cam 23 is engaged with the rotating body 30, so that the rotating body 30 and the main cam 23 can rotate together.

The main clutch 24 is composed of multiple outer peripheral engaging plates 24a and multiple inner peripheral engaging plates 24b arranged alternately in the left-right direction. The outer peripheral portion of the outer peripheral engaging plate 24a is supported by the outer peripheral surface portion 27c, and is rotated integrally with the clutch holder 27 and is movable in the left-right direction relative to the clutch holder 27. The inner peripheral portion of the inner peripheral engaging plate 24b is supported by the rotating body 30, and is rotated integrally with the rotating body 30 and is movable in the left-right direction relative to the rotating body 30.

The main clutch 24 has the function of transmitting power between the rotor 30 and the main cam 23 by the outer peripheral engaging plate 24a and the inner peripheral engaging plate 24b approaching each other and engaging or slipping. In the main clutch 24, the magnitude of the power transmitted from the rotor 30 to the main cam 23 changes depending on the magnitude of the frictional force between the outer peripheral engaging plate 24a and the inner peripheral engaging plate 24b.

The armature 25 is disposed between the control clutch 22 and the main cam 23 on the outer periphery of the control cam 21. The armature 25 is made of a ferromagnetic material such as iron, and is moved left and right by the thrust force generated in the magnetic field depending on the state of current flow to the coil 20.

A restricting portion 32 is attached to the outer periphery of the shaft insertion portion 16 in the differential case 10. The restricting portion 32 is, for example, composed of a snap ring 32a attached to the shaft insertion portion 16 and a plate 32b attached to one surface of the snap ring 32a in the axial direction, and is positioned between the main cam 23 and the rotor 30.

When the pinion shafts 11, 11 are rotated, a reaction force is applied to the rotating body 30 that is meshed with the pinion shafts 11, 11, causing it to move toward the main cam 23. However, when the rotating body 30 comes into contact with the restricting portion 32, the movement of the rotating body 30 toward the main cam 23 is restricted.

In this way, the differential device 1 has a restricting portion 32 attached to the differential case 10, which restricts the displacement of the rotating body 30 toward the differential limiting mechanism 19.

Therefore, the regulating portion 32 regulates the displacement of the rotating body 30 toward the differential limiting mechanism 19, thereby preventing the rotating body 30 from coming into contact with the differential limiting mechanism 19 and ensuring a stable driving state of the differential limiting mechanism 19.

In addition, in the differential device 1, the rotating body 30 is positioned around the differential case 10, and the differential case 10 and the rotating body 30 are positioned side by side in the radial direction of the axle 115. This means that the rotating body 30 does not protrude beyond the differential case 10 in the axial direction of the axle 115, making it possible to reduce the size of the differential device 1.

Furthermore, since the differential limiting mechanism 19 is positioned around the differential case 10, and the differential case 10 and the differential limiting mechanism 19 are positioned side by side in the radial direction of the axle 115, the differential limiting mechanism 19 does not protrude from the differential case 10 in the axial direction of the axle 115, and the differential device 1 can be made even more compact.

Furthermore, the differential case 10, the pinion shafts 11, 11, the pinion gears 12, 12, the side gears 13, 13, the rotor 30, and the differential limiting mechanism 19 are all arranged inside the housing 2.

As a result, the differential case 10, pinion shafts 11, 11, pinion gears 12, 12, side gears 13, 13, rotors 30, and differential limiting mechanism 19 are all housed in the same housing 2, making it possible to further reduce the size of the differential device 1.

<Operation in Differential Device>
The operation of the differential mechanism 8 and the differential limiting mechanism 19 in the differential device 1 will be described below (see FIGS. 2 to 4).

When power is transmitted from the engine 101 or the like to the drive gear 7 via the drive shaft 6, the ring gear 9 meshed with the drive gear 7 rotates, and the ring gear 9 and the differential case 10 rotate together, while the pinion gears 12, 12 revolve with the rotation of the differential case 10. The pinion shafts 11, 11 revolve with the revolution of the pinion gears 12, 12, and the rotating body 30 meshed with the pinion shafts 11, 11 rotates with the rotation axis 30a as a fulcrum.

When the pinion gears 12, 12 revolve, the side gears 13, 13 meshed with the pinion gears 12, 12 are rotated, and the side gears 13, 13 and the shaft connecting members 5, 5 are rotated together, and power is transmitted to the drive wheels 105, 105 via the axles 115, 115, causing the vehicle 100 to run.

At this time, when the vehicle 100 is moving straight, the resistance from the road surface to the left and right drive wheels 105, 105 is equal, so the pinion gears 12, 12 revolve with the rotation of the differential case 10 but do not rotate, and the rotational force of the pinion gears 12, 12 is transmitted equally to the side gears 13, 13 that are meshed with the pinion gears 12, 12.

On the other hand, when the vehicle 100 turns, the resistance from the road surface to the left and right drive wheels 105, 105 is different, and one side gear 13 tries to push back against the pinion gears 12, 12, causing the pinion gears 12, 12 to revolve and rotate. Therefore, the rotation of the other side gear 13 is accelerated by the rotation of the pinion gears 12, 12, creating a rotation difference between the left and right drive wheels 105, 105, ensuring smooth driving conditions.

At this time, the pinion shafts 11, 11 rotate together with the pinion gears 12, 12. The rotating body 30 meshed with the pinion shafts 11, 11 rotates around the rotating shaft 30a as a fulcrum at a speed different from that of the differential case 10 due to the rotation of the pinion shafts 11, 11.

In addition, for example, in the case of sports driving such as going around sharp curves at high speed, as described above, a drive signal having a magnitude corresponding to the acceleration, etc. of the vehicle 100 is sent from the electronic control unit to the differential limiting mechanism 19, and the differential limiting mechanism 19 limits the operating state of the differential mechanism 8 as follows.

When a drive signal is input from the electronic control unit to the differential limiting mechanism 19, the differential limiting mechanism 19 starts to operate, a drive current is supplied to the coil 20, and a magnetic field is generated around the coil 20, attracting the armature 25 toward the control clutch 22 (see FIG. 4). At this time, as the drive gear 7 rotates, the differential case 10, the rotor 30, the main cam 23, the clutch holder 27, the outer peripheral engagement plate 24a and the inner peripheral engagement plate 24b of the main clutch 24, and the outer peripheral friction plate 22a of the control clutch 22 rotate together relative to the housing 2.

When the armature 25 is moved toward the control clutch 22, the outer friction plate 22a and the inner friction plate 22b are pressed by the armature 25 and move closer to each other, engaging or slipping. When the outer friction plate 22a and the inner friction plate 22b are engaged or slipping, power can be transmitted between the control cam 21 and the clutch holder 27.

At this time, the main cam 23 is rotating, and power is transmitted between the main cam 23 and the control cam 21 via the ball 27, but a rotational difference occurs between the control cam 21 and the main cam 23. Therefore, the balls 29 held in the recesses 21a and 23a roll on the inclined surfaces of the recesses 21a and 23a, and the main cam 23 is pressed and moved toward the main clutch 24 by the balls 29.

When the main cam 23 moves, the outer peripheral engaging plate 24a and the inner peripheral engaging plate 24b of the main clutch 24 are pressed and moved by the main cam 23, approaching each other and engaging or slipping. When the outer peripheral engaging plate 24a and the inner peripheral engaging plate 24b engage or slip, the differential case 10 and the rotating body 30 are connected via the differential limiting mechanism 19, and power is transmitted between the differential case 10 and the rotating body 30.

The differential case 10 and the rotor 30 are connected via the differential limiting mechanism 19, so that the differential limiting mechanism 19 applies a rotational load to the pinion shaft 11 via the rotor 30, causing the rotor 30 to rotate in conjunction with the rotation of the differential case 10, allowing the rotor 30 to rotate at the same speed as the differential case 10.

In this way, the differential case 10 and the rotor 30 are connected via the differential limiting mechanism 19, a rotational load is applied to the pinion shaft 11, and the differential operation of the differential mechanism 8 is limited by the differential limiting mechanism 19, making it possible to return the loss of driving force caused by the operation of the differential mechanism 8 to the differential case 10. In addition, by adjusting the level of the drive signal input from the electronic control unit to the differential limiting mechanism 19, it is possible to adjust the engagement state of the outer peripheral engaging plate 24a and the inner peripheral engaging plate 24b in the main clutch 24, and control the return rate of the lost driving force to the differential case 10.

<Summary>
As described above, the differential device 1 includes the pinion shaft 11 which is rotatable relative to the differential case 10, the pinion gear 12 which rotates integrally with the pinion shaft 11 and revolves in conjunction with the rotation of the differential case 10, the side gear 13 which is meshed with the pinion gear 12 and transmits power to the axle 115, the rotating body 30 which is meshed with the pinion shaft 11 and rotates integrally with the pinion shaft 11, and the differential limiting mechanism 19 which applies a rotational load to the pinion shaft 11 via the rotating body 30.

Therefore, since the transmission gear portion 30b is configured to apply a rotational load to the pinion shaft 11 via the rotor 30 meshed with the gear portion 11b, the rotor 30 is positioned close to the pinion shaft 11 and the differential limiting mechanism 19 is positioned close to the rotor 30. This makes it possible to avoid an increase in size while improving functionality in a configuration equipped with a differential limiting mechanism 19 that has a function different from that of the differential mechanism 8 that performs differentials.

In addition, because the rotor 30 is positioned close to the pinion shaft 11 and the differential limiting mechanism 19 is positioned close to the rotor 30, it is possible to position the differential limiting mechanism 19 and the rotor 30 close to the center of rotation (center of rotation) of the pinion gear 12, which is the center of rotation of the differential mechanism 8, and the structure arranged inside the housing 2 can be made as close as possible to a configuration that is linearly symmetrical with respect to the center of rotation of the differential mechanism 8.

In particular, by making the structure arranged inside the housing 2 as linearly symmetrical as possible with respect to the center of rotation of the differential mechanism 8, it is possible to ensure a good balance of the differential device 1 and the vehicle 100 equipped with the differential device 1, and difficulties in designing the strength of the vehicle body are unlikely to arise.

In addition, by avoiding an increase in size of the differential device 1, interference between the differential device 1 and other structures such as fuel piping is less likely to occur, and design freedom for each part of the vehicle 100 can be improved.

Furthermore, in the differential device 1, a clutch mechanism having a control clutch 22 and a main clutch 24 is provided in the differential limiting mechanism 19.

As a result, it is possible to control the magnitude of the rotational load applied to the pinion shaft 11 depending on the operating state of the versatile clutch mechanism, and the rotational state of the pinion shaft 11 can be controlled while simplifying the structure.

In the above, a differential mechanism 8 having two pinion shafts 11 and two pinion gears 12 is shown as an example, but the differential mechanism 8 may be configured with three or more pinion shafts 11 and three or more pinion gears 12 in the circumferential direction.

The differential limiting mechanism 19 may be of a mechanically operated type or an electronically operated type.

REFERENCE SIGNS LIST 1 Differential device 2 Housing 7 Drive gear 8 Differential mechanism 10 Differential case 10a Rotating shaft 11 Pinion shaft 11b Gear portion 12 Pinion gear 13 Side gear 19 Differential limiting mechanism 30 Rotating body 30a Rotating shaft 30b Transmission gear portion 32 Restricting portion 115 Axle

Claims (6)

a differential case rotated by power transmitted via a drive gear;
a pinion shaft having a gear portion and rotatable relative to the differential case;
a pinion gear that rotates integrally with the pinion shaft and revolves in accordance with the rotation of the differential case;
a side gear that is meshed with the pinion gear and transmits power from the drive gear to an axle;
a rotor having a transmission gear portion meshed with the gear portion and rotated by meshing with the gear portion of the pinion shaft;
a differential limiting mechanism that applies a rotational load to the pinion shaft via the rotor,
The rotor is rotatable at a speed different from that of the pinion shaft ,
The differential limiting mechanism is provided with a clutch mechanism,
a coil for operating the clutch mechanism is provided in the differential limiting mechanism,
The coil and the rotor are positioned apart from each other in the direction of the rotation axis of the differential case.
Differential device. The differential device according to claim 1 , wherein the rotors are positioned around the differential case. 3. The differential device according to claim 2, wherein a rotation axis of the differential case and a rotation axis of the rotor are aligned. 4. The differential device according to claim 1, 2 or 3, wherein the differential limiting mechanism is positioned around the differential case. The differential case, the pinion shaft, the pinion gear, the side gear, the rotor, and the limited slip differential mechanism are disposed inside a housing.
A differential device according to claim 1, 2, 3 or 4 . the rotor is located between the pinion shaft and the limited slip differential mechanism in an axial direction of a rotation shaft in the differential case,
A restricting portion is attached to the differential case to restrict displacement of the rotor toward the differential limiting mechanism.
A differential device according to claim 1, 2, 3, 4 or 5 .

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