JPH09144840A - Differential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a stable high differential limiting force even when the number of differential revolutions is low and release a pump case from the influence of the thrust force of a side gear. SOLUTION: A differential device comprises a differential case 3 rotationally driven by an engine, a differential gear mechanism 4a, a friction clutch 45 for differential limit, a plurality of sets of gear pumps 49 to receive differential rotation for drive, and an actuator 47 to receive the delivery pressure of the pump 49 and fasten a friction clutch 45. A pump 49 comprises an internal tooth gear 63 rotated integrally with the differential case 3, a plurality of external tooth gears 65 engaged with the gear 63, and a pump case 55 to rotatably support each gear 65 and be axially relatively movably coupled to the outer periphery of the boss part 29 of a side gear 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential device used for a vehicle.

[0002]

2. Description of the Related Art Some conventional differential devices incorporate a gear pump which is driven by receiving differential rotation, and engages a friction clutch for limiting a differential with the pump pressure. The gear pump is configured to suck oil from an oil reservoir provided in a case that houses a differential device.

Gear pumps are classified into inward and external types.

In a differential device using a circumscribing type gear pump, an inner gear to which differential rotation is input is generally arranged coaxially with the differential device, and an outer gear is arranged on an outer periphery of an inner gear, so that a differential case is provided. An oil port is concentrically formed at a position opposed to the vicinity of the meshing portion of the inner and outer gears.

Further, the one shown in FIG. S. Pa
It is the differential device 201 described in the tent 5310388 registration certificate, which is an example of the differential device using an internal gear pump.

The differential device 201 includes a pinion shaft 205 fixed to a differential case 203,
A bevel gear type differential mechanism 213 including a pinion gear 207 rotatably supported on a pinion shaft 205 and side gears 209 and 211 meshing with the pinion gear 207, a multi-disc clutch 215 for limiting a differential, and a multi-disc clutch 215. Hydraulic actuator 217 for fastening
And a gear pump 219 for operating the hydraulic actuator 217. The side gears 209 and 211 are spline-connected to the axles 221 and 223, respectively.

The multi-plate clutch 215 and the gear pump 219 are arranged between the axle 221 on the side gear 209 side and the differential case 203, and the gear pump 219 is attached to the axle 221.
Driven by the differential rotation of the differential mechanism 213, the hydraulic actuator 217 receives the discharge pressure of the gear pump 219 and presses the multi-plate clutch 215 to limit the differential of the differential mechanism 213.

[0008]

However, the external gear pump is restricted by the presence of the outer gear and the inner gear cannot be made large in diameter. Therefore, the P.P. C.
D (pitch circle diameter of circle in which oil ports are arranged) also becomes small. Therefore, the P. C. Since the oil port is densely opened on D, the strength of the differential case is reduced accordingly.

When the driven inner gear has a small diameter, the rotation speed of the outer gear (the rotation speed of the gear pump) when receiving differential rotation is low, so that the discharge amount per rotation speed is small and high. Pump pressure does not occur. Therefore, a large differential limiting force cannot be obtained, the dynamic performance of the vehicle cannot be sufficiently improved, and the dependency of the differential limiting function on the pump pressure becomes high, and the pump pressure fluctuates with a slight change in the differential rotation speed. Then
The differential limiting function becomes unstable.

Further, the oil port P. C. If D is small, it is necessary to raise the oil level in the oil sump by that amount, but in order to raise the oil level, a large amount of oil is used.
If the oil level is raised, the viscosity of the oil increases the rotational resistance that the differential device receives, and this power loss reduces the fuel efficiency of the engine.

Further, in a conventional differential device using an external gear pump, an inner gear is fixed to an axle connected to an output side gear, and a pump case is arranged between the side gear and the differential case. There is something.

In such a structure, the thrust force of the side gear may bend the pump case and cause galling between the gear and the pump case. To prevent this, the pump case is made thicker, This leads to an increase in the weight and size of the device.

Further, the differential device 201 shown in FIG.
As described above, the internal gear pump 219 is used. Since the gear pump 219 is a set of gear pumps including an external gear 225 and an internal gear 227, the pump has a small discharge amount per rotational speed. The pressure is low. Therefore,
A large differential limiting force cannot be obtained, and the dynamic performance of the vehicle cannot be sufficiently improved.

Therefore, the present invention is a differential device which drives a built-in gear pump by differential rotation and presses a friction clutch to obtain a differential limiting force, which is stable and has a large difference even when the differential rotation speed is low. An object of the present invention is to provide a differential device in which a dynamic limiting force is obtained and the pump case is released from the influence of the thrust force of the side gear.

[0015]

A differential device according to a first aspect of the present invention is a differential gear which is rotationally driven by a driving force of an engine and a differential gear which outputs the rotation of the differential gear from a pair of side gears via a pinion gear. Mechanism, a friction clutch that limits the differential of the differential gear mechanism, a plurality of sets of internal gear pumps that are rotationally driven by the differential rotation of the differential gear mechanism, and the discharge pressure of this gear pump. An actuator for pressing and fastening the friction clutch, wherein the gear pump has an internal gear that rotates integrally with the differential case;
A plurality of external gears meshing with the internal gear, and a pump case that rotatably supports each external gear and is connected to the outer periphery of the boss portion of the side gear so as to be relatively movable in the axial direction. And

When differential rotation occurs in the differential gear mechanism, the external gear of each pump chamber and the internal gear of the differential case are separated by the relative rotation of the pump case and the differential case, which are integrated with the side gear. The mesh pump rotates, each gear pump is driven, and the actuator is actuated by receiving these discharge pressures, the friction clutch is pressed and the differential is limited.

Since the pump work and the frictional resistance of the friction clutch increase as the differential rotation speed increases, a speed-sensitive differential limiting function is thus obtained.

Further, unlike the conventional example of FIG. 4 in which the differential gear is limited by one set of gear pumps, a large differential limiting force is obtained because a plurality of sets of gear pumps are used, and the movement of the vehicle is reduced even when the differential rotation speed is low. The performance can be improved sufficiently.

In addition to this, unlike the external gear pump, the internal gear pump can rotate the internal gear because the internal gear (drive gear) can have a large diameter without being restricted by the external gear. The rotation speed of the external gear becomes higher, and the gear pump is driven at high speed to obtain a large oil discharge amount and pump pressure. Therefore, the dependency of the differential limiting function on the pump pressure is reduced, the differential limiting function is released from the influence of the fluctuation of the differential rotation speed, and the differential limiting function is stabilized.

Further, in the internal gear pump, as described above, the internal gear can have a large diameter, so that the P.P.
C. D also has a large diameter, and even if a plurality of sets of gear pump oil ports are provided, the arrangement of the oil ports becomes rough, so that the reduction in the strength of the differential case is alleviated.

Further, the oil port P. C. Since D is large and the oil level in the oil sump can be lowered by that much, the amount of oil to be put into the case can be reduced, and the rotational resistance and power loss that the differential device receives due to oil can be greatly reduced, improving the fuel efficiency of the engine. .

In addition to this, since the boss portion of the side gear is connected to the pump case so as to be relatively movable in the axial direction, the thrust force of the side gear can be received by the differential case.
Thus, the deflection of the pump case due to the thrust force of the side gear and the galling of the pump case and the gear are prevented, and it is not necessary to make the pump case thick, which makes the differential device heavy and large. can avoid.

[0023]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a differential device 1 according to this embodiment. Note that the left and right directions are the left and right directions in FIG. 1, and the members and the like without reference numerals are not shown.

As shown in FIG. 1, the differential case 3 of the differential device 1 is constructed by fixing a casing body 5 and a cover 7 with bolts 9. The differential case 3 is arranged inside the differential carrier, and an oil reservoir is formed in the differential carrier.

The left and right boss portions 11 and 13 of the differential case 3 are supported by the differential carrier via bearings. A ring gear is fixed to the differential case 3 with bolts, and the ring gear meshes with the drive gear of the drive force transmission system.
Thus, the differential case 3 is rotationally driven by the driving force of the engine via this driving force transmission system.

Inside the diff casing 3, a plurality of pinion shafts 17 are radially arranged around the boss portion 15, and the chamfered portion 19 formed at the outer end of each pinion shaft 17 is a diff casing. -It engages with the groove 21 of the sleeve 3 and is connected in the rotational direction. A pinion gear 23 is rotatably supported on each pinion shaft 17.

Inside the differential case 3, left and right output side gears 25, 27 are arranged. These side gears 25 and 27 are integrally formed with the respective boss portions 29 and 31, and the side gears 25 and 27 are connected to the pinion gear 2 respectively.
It is supported from the outside in the radial direction by meshing with 3. A spherical washer 33 is arranged between the pinion gear 23 and the differential case 3, and bears the centrifugal force of the pinion gear 23 and the meshing reaction force that the pinion gear 23 receives by meshing with the side gears 25 and 27. .

The boss portion 29 of the left side gear 25 is a differential gear.
The boss portion 31 of the right side gear 27 is rotatably supported by a bearing portion 35 of the gear 3, and the boss portion 31 of the right side gear 27 is rotatably supported by a bearing portion 37 of the differential case 3. A washer 39 is arranged between the right side gear 27 and the differential case 3. The side gears 25 and 27 are spline-connected to the left and right axles via the boss portions 29 and 31, respectively.

Thus, the bevel gear type differential gear mechanism 4
1 is configured. The pinion shaft 17, the pinion gear 23, and the side gears 25, 27 of the differential gear mechanism 41.
Are axially movable on the groove 21.

The driving force of the engine for rotating the differential case 3 is distributed from the pinion shaft 17 to the side gears 25 and 27 via the pinion gear 23 and transmitted to the wheel side via each axle. Further, for example, when a driving resistance difference occurs between the wheels during traveling on a rough road, the driving force of the engine is differentially distributed to each wheel side by the rotation of each pinion gear 23.

A multi-plate clutch 45 (friction clutch) is arranged between the top portion 43 of the left side gear 25 and the differential case 3. Further, a hydraulic actuator 47 (actuator) is arranged on the left side thereof, and further on the left side thereof, as shown in FIG. 2, four sets of internal gear pumps 4 are provided.
9 are arranged.

A back ring 51 is arranged between the multi-plate clutch 45 and the differential case 3 to bear the pressing force on the multi-plate clutch 45.

The piston 53 of the hydraulic actuator 47 is disposed between the pump case 55 of the gear pump 49 and the differential case 3 via seal rings 57 and 59 so as to be movable in the axial direction. Also, the hydraulic actuator 4
Cylinder 61 of 7 includes piston 53 and pump case 55.
And the differential case 3.

As shown in FIG. 2, each gear pump 49 comprises a pump case 55, an internal gear 63, four external gears 65, check valve mechanisms 67, 69 and the like.

The inner circumference of the pump case 55 is the left side gear 2.
A spline portion 71 is connected to the outer periphery of the boss portion 29 of No. 5 so as to be movable in the axial direction. The outer circumference of the internal gear 63 is connected to the inner circumference of the differential case 3 by a spline portion 73. The pump case 55 is provided with four pump chambers 75 at equal intervals in the circumferential direction, and the external gears 65 are slidably and rotatably housed in these pump chambers 75. It meshes with the internal gear 63 to form four sets of gear pumps 49.

Therefore, when differential rotation occurs in the differential gear mechanism 41, the gears 63 and 65 are rotated by the relative rotation between the differential case 3 (internal gear 63) and the left side gear 25 (pump case 55). The gear pump 49 operates by meshing rotation.

As shown in FIG. 3, the cover 7 of the differential case 3 is provided with a suction port at a position opposed to both circumferential sides (the suction side and the discharge side of the gear pump 49) of the meshing portion of the gears 63 and 65.
A total of four sets of ports 77 and 77 are provided, and a valve seat 79 that communicates with each suction port 77 is provided. Further, as shown in FIG. 2, the gear case 4 is attached to the pump case 55.
9, a discharge port 81 is provided at a position facing the suction side and the discharge side of 9,
There are 4 sets of 81 in total, and as shown in FIG.
A valve seat 83 communicating with each discharge port 81 is provided.

Each check valve mechanism 67 has a valve seat 79.
And a disc-shaped suction side check valve 85 arranged so as to be able to close the valve seat 79, and the check valve 85 is prevented from falling off by the side surfaces of the gears 63 and 65. Valve seat 7
9 is directed to the gear pump 49 side, and each check valve mechanism 67 causes oil to flow from the suction port 77 to the gear pump 49 by opening and closing the valve seat 79 by the check valve 85, and at the same time from the gear pump 49. -G7
Return to 7 and shut off the oil.

Each check valve mechanism 69 comprises a valve seat 83 and a disc-shaped discharge side check valve 87 arranged so as to be able to close the valve seat 83.
7 is a plate ring 89 mounted on the pump case 55.
It is prevented from falling off. The valve seat 83 is an actuator.
The check valve mechanism 69,
From the gear pump 49 to the discharge port 81 (actuator 4
(7 side), and at the same time, the return oil from the discharge port 81 side is shut off.

When each gear pump 49 rotates, whichever direction the gear pump 49 rotates, on the suction side of each gear pump 49, the check valve mechanism 67 is opened, oil is sucked into the gear pump 49, and the check valve mechanism 69 is opened. It is blocked and the return oil from the actuator 47 side is blocked. On the discharge side of each gear pump 49, the check valve mechanism 67 is closed to shut off the oil returning from the gear pump 49 to the outside of the differential case 3, and the check valve mechanism 69 is opened so that the actuator 47 receives the oil. Is supplied.

In this way, when each gear pump 49 rotates, its rotation direction (the differential rotation direction of the differential gear mechanism 41:
Regardless of the direction of travel of the vehicle)
Oil pressure is applied to the cylinder-61.

An oil pocket 89 is attached to the side surface of the cover 7. The oil pocket 89 is composed of a compartment member 91, a seal member 93 lining the compartment member 91 to make it liquid-tight, and a ring 95, and an oil chamber 97 is provided between the cover member 91 and the cover 7.
Is formed.

The oil pocket 89 is slidably rotatable with respect to the cover 7, and an oil pipe is connected to the oil pocket 89. The oil pipe communicates with the oil reservoir of the differential carrier and the oil pocket 89 via the oil strainer and the control valve.

When each gear pump 49 is operated, oil is sucked from the oil reservoir through the oil pipe to fill the oil chamber 97, and the oil pressure is applied to the cylinder 61 as described above.

When an oil pressure is applied to the cylinder 61, the hydraulic actuator 47 presses and engages the multi-plate clutch 45 via the piston 53, and the frictional resistance of the multi-plate clutch 45 and the pump work of each gear pump 49 are performed. This limits the differential of the differential gear mechanism 41. Since the frictional resistance of the multi-plate clutch 45 and the pump work of the gear pump 49 increase as the differential rotation speed increases, a differential limiting function sensitive to the differential rotation speed can be obtained.

When the differential rotation speed becomes lower than a certain value, the check valve functions 67 and 69 cause the oil ports to operate.
Is blocked and the pump function of the gear pump 49 stops,
The differential limitation is released.

The piston 53 is provided with an orifice 99, and when oil pressure is applied to the cylinder-61,
The air mixed in the oil is discharged, and further the oil is discharged appropriately. The discharged oil lubricates the multi-plate clutch 45, the meshing parts of the gears, the sliding parts of the pinion gear 23 with the pinion shaft 17 and the spherical washer 33, and is centrifuged from the openings 101 and 103 provided in the differential case 3. It is discharged to the outside by force and returns to the oil reservoir of the differential carrier.

While the differential gear mechanism 41 transmits torque,
A meshing reaction force with the pinion gear 23 is applied to each of the side gears 25 and 27. The left side gear 25 moves to the left by this meshing reaction force. Also, the right side gear 2
Since 7 is in contact with the differential case 3 via the washer 39 and cannot move to the right, the side gear 25 receives a meshing reaction force from the side gear 27 in addition to its meshing reaction force.

However, this large meshing reaction force (thrust force) received by the side gear 25 is generated by the spline connection of the pump case 55 of the gear pump 49 to the boss portion 29 of the side gear 25 so as to be movable in the axial direction. Unlike the example, it does not hang on the pump case 55, but hangs on the side wall 105 of the differential case 3.

Thus, the differential device 1 is constructed.

A vehicle using the differential device 1 is
Due to the large speed-sensitive differential limiting function, the drive wheels are prevented from idling on rough roads and the running performance is improved.

As described above, in the differential device 1, unlike the conventional example shown in FIG. 4, four sets of gear pumps 4 are provided.
By using 9, the sufficient differential limiting force can be obtained even when the differential rotation speed is low, and the kinematic performance of the vehicle can be sufficiently improved.

Moreover, since the internal gear pump 49 is used, unlike the external gear pump, the internal gear 63 has a large diameter without being restricted by the external gear, as shown in FIGS. , Oil ports 77, 77, 81, 81. C.
D also has a large diameter. Therefore, like the differential device 1, four sets of oil ports 77, 7 for the gear pump 49 are provided.
Even when 7, 81 and 81 are formed on the differential case 3, the arrangement of these becomes coarse, so that the reduction in strength of the differential case 3 is alleviated.

Further, since the internal gear 63 has a large diameter,
The rotation speed of the external gear 65 per rotation speed of the internal gear 63 increases, the amount of oil discharged from each gear pump 49 increases, and the pump pressure increases. Therefore, in combination with the effect of arranging the plurality of gear pumps 49, the dependency of the differential limiting function on the pump pressure is reduced, and the differential limiting function is stabilized by being released from the influence of the variation in the differential rotation speed.

In addition to this, oil port P. C. D
By increasing, the oil level in the oil sump can be lowered accordingly. Differential device 1
During rotation, the oil in the oil sump is swirled by the ring gear and sticks to the inner wall of the differential carrier.By lowering the oil level, the thickness of this sticky oil becomes thinner and the amount of oil to be put into the differential carrier can be reduced. . Further, the rotational resistance and power loss received by the differential device 1 due to the oil are reduced, and the fuel efficiency of the engine is greatly improved.

Since the boss portion 29 of the side gear 25 is connected to the pump case 55 so as to be relatively movable in the axial direction, the differential case 3 can receive the thrust force of the side gears 25 and 27. Thus, the bending of the pump case 55 due to the thrust force of the side gears 25 and 27 and the pump case
It is possible to prevent galling between the gear 55 and the gears 63 and 65, and it is not necessary to increase the thickness of the pump case 55, so that the weight and size of the differential device 1 can be avoided.

In the present invention, the differential gear mechanism is not limited to the bevel gear type, and for example, the torque sensitive type is utilized by utilizing the friction resistance between the differential gears and the friction resistance between each gear and the differential case. A helical gear type differential gear mechanism which obtains the differential limiting function may be used.

If such a differential gear mechanism is used, it is possible to obtain a differential device having not only the torque-sensitive differential limiting function but also the speed-sensitive differential limiting function by the friction clutch and the pump.

The clutch for limiting the differential is not limited to the multi-plate clutch, but may be another friction clutch such as a cone clutch.

The differential device of the present invention includes a front differential (a differential device arranged on the front wheel axle), a rear differential (a differential device arranged on the rear wheel axle), and a center differential (engine driving force applied to the front wheel). And a differential device for distributing to the rear wheels).

[0061]

As described above, the differential device according to the first aspect of the present invention, unlike the conventional example, uses a plurality of sets of gear pumps, so that a large differential limiting force can be obtained and the vehicle motion can be achieved even when the differential rotation speed is low. The performance can be improved sufficiently.

Further, unlike the external gear pump, the internal gear pump can increase the diameter of the internal gear, so that the rotation speed of the external gear with respect to the rotation of the internal gear increases, and the gear pump operates at high speed. When driven, a large oil discharge amount and pump pressure are obtained. Therefore, the dependency of the differential limiting function on the pump pressure is reduced, the differential limiting function is released from the influence of the fluctuation of the differential rotation speed, and the differential limiting function is stabilized.

Since the internal gear can have a large diameter, the P.P. C. D also has a large diameter, and even if a plurality of sets of gear pump oil ports are provided, the reduction in the strength of the differential case is alleviated.

Further, the oil port P. C. Since D is large and the oil level in the oil sump can be lowered by that much, the amount of oil to be put in the case can be reduced, and the rotational resistance and power loss of the oil received by the differential device can be reduced, greatly improving the fuel efficiency of the engine. To do.

In addition to this, since the boss portion of the side gear is connected to the pump case so as to be relatively movable in the axial direction, the thrust force of the side gear can be received by the differential case, and the pump case due to the thrust force of the side gear can be applied. Bending and galling of the pump case and the gear are prevented, and it is not necessary to make the pump case thick, and the weight and size of the differential device can be avoided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view of a conventional example.

[Explanation of symbols]

 1 Differential Device 3 Differential Case 23 Pinion Gear 25, 27 Side Gear 29 Boss of Side Gear 25 41 Differential Gear Mechanism 45 Multiple Disc Clutch (Friction Clutch) 47 Hydraulic Actuator (Actuator) 49 Internal Gear Pump 55 Pump Case Gear 63 Internal gear 65 External gear

Claims (1)

[Claims] 1. A differential case which is rotationally driven by a driving force of an engine, a differential gear mechanism which outputs the rotation of the differential case from a pair of side gears through a pinion gear, and a differential between the differential gear mechanism is limited. Friction clutch, a plurality of sets of internal gear pumps that are rotationally driven by the differential rotation of the differential gear mechanism, and an actuator that presses and engages the friction clutch by receiving the discharge pressure of the gear pumps. The gear pump includes an internal gear that rotates integrally with the differential case,
A plurality of external gears meshing with the internal gear, and a pump case that rotatably supports each external gear and is connected to the outer periphery of the boss portion of the side gear so as to be relatively movable in the axial direction. Differential device.