JPH0674823B2 - Differential limiting mechanism in differential device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a differential device with a mechanism for limiting the differential with a multi-plate clutch when the input / output shafts rotate relative to each other, and more particularly to a vane pump. It relates to a differential limiting mechanism with a built-in.

[Conventional technology]

As is well known, a differential limiting mechanism in a differential device causes a differential resistance in the differential device when a rotational difference occurs between two transmission members that are relatively rotatable in the differential device. Conventionally, the differential limiting mechanism includes, for example, a mechanical type, a viscous coupling (viscus coupling) type, a pump type, and the like.

The differential limiting mechanism of the present invention belongs to the above-mentioned pump type, and the prior art thereof is, for example, JP-A-61-282646.
There is one described in the publication.

This means that in a differential limiting mechanism interposed between two relatively rotatable transmission members in a differential device, a pump case provided on one of the transmission members and an elastic surface on the inner surface of the pump case. A vane pump having a plurality of vanes slidably contacting with the pump and an eccentric rotor with respect to the pump, the rotor being coupled to the other transmission member and functioning as an intake port or a discharge port depending on the rotation direction of the rotor. In order to do so, between the pair of circulation ports provided in the pump case, there is provided a first circulation direction regulation circuit which allows only the circulation of the working fluid to the circulation ports, and only the circulation of the working fluid from both the circulation ports. Is connected to the second circulation direction regulation circuit which allows the above-mentioned ", and both circulation direction regulation circuits are mutually connected via a diaphragm".

Further, the same first circulation direction regulation circuit and the second circulation direction regulation circuit as described above are connected, and "both circulation direction regulation circuits are connected via mutually parallel throttles and relief valves", that is, In addition to the above configuration, there is also a throttle valve in which a relief valve is connected in parallel.

In both cases, when a differential action occurs in the differential device, the vane pump exerts a differential resistance.

[Problems to be Solved by the Invention]

The above-mentioned conventional differential limiting mechanism using a vane pump may have the following problems.

i) The transmission member on the output side of the differential device rotates faster or later than the input side, and rotation between the two transmission members in the forward and reverse directions occurs relatively. Therefore, when the vane pump is used for the differential limiting mechanism, it is necessary to make the pair of through holes formed in the pump case of the vane pump function as suction holes or discharge holes depending on the relative rotation direction with the rotor. Therefore, in the above-mentioned conventional example, the first circulation direction regulating circuit
Although the second circulation direction regulation circuit and the like are provided, the hydraulic circuit is complicated and the manufacturing process is difficult.

ii) In order to prevent backflow of the working fluid, a check valve is installed in the above circuit.
Although it is necessary to provide one as well, since the pump case becomes larger and heavier, it may not be possible to mount it on a small vehicle.

The present invention relates to a differential limiting mechanism with a built-in vane pump in a differential gear, and is intended to solve the above conventional problems. That is, an object of the present invention is to provide a differential limiting mechanism in a differential device, which has a small and simple structure and is capable of automatically and instantaneously switching between a suction side and a discharge side of a vane pump. It is in.

Configuration of the Invention [Means for Solving the Problems] A differential limiting mechanism in a differential device according to the present invention is a differential mechanism that uses a multi-disc clutch (2) when the input / output shafts (19) (21) are relatively rotated. In a differential device (1) with a mechanism for limiting the movement, between the two transmission members (3) (4) on the input and output sides, which are relatively rotatable in the forward and reverse directions in the differential device (1). Is provided with a vane pump (6) capable of supplying the working fluid (5) for pressing the multi-plate clutch and a direction switching valve (7), and the vane pump (6) has a rotor having a large number of vanes (9). (8) is provided on the input-side transmission member (3), and a pump case (10) capable of slidingly contacting the vane (9) with the inner peripheral surface is provided on one output-side transmission member (4). A suction hole (12) and a discharge hole (13) for the working fluid (5) are formed on the side surface (11) of the case (10), The direction switching valve (7) is in the shape of a hollow disc, and is located between the side surface (11) of the pump case (10) where the suction hole (12) and the discharge hole (13) are formed and the side surface (14) of the rotor (8). Spring (15) for pressure contact with the side surface (14) of the rotor (8)
Is provided with a stopper (16) for stopping the forward / reverse rotation of the switching valve (7) at a constant angle, and the case (10) is sucked when the switching valve (7) is stopped by the forward / reverse rotation. The suction ports (17) and (18) communicating with the suction hole (12) are formed at the positions corresponding to the holes (12), and at the positions corresponding to the discharge holes (13) of the case (10).
By forming the discharge port (35) communicating with the discharge hole (13), the switching valve (7) rotates by a certain angle in accordance with the positive relative rotation of the input / output shafts (19) (21), One of the inlet (17) and the outlet (35) of the switching valve (7) is a case (10).
Communicates with the suction hole (12) and the discharge hole (13) of the switch valve, and the switching valve (7) reversely rotates by a certain angle in accordance with the relative rotation in the opposite direction,
The other suction port (18) and discharge port (35) of the switching valve (7) communicate with the suction hole (12) and discharge hole (13) of the case (10) to limit the differential. It is a thing.

In the above structure, the differential device (1) may be for the center differential or for the rear differential. Also, even with planetary gear type,
A bevel gear type may be used.

The two transmission members (3) and (4) on the input and output sides are, for example, in the case of a center differential using a planetary gear,
The transmission member (3) on the input side is a member that rotates together with the input shaft (19) from the transfer, while the transmission member (4) on the output side is a member that rotates together with the chain wheel (20) to the front wheels. is there. Incidentally, (21) is an output shaft to the rear wheels, which transmits the driving force from the center differential device to the rear wheels. In the case of the rear diff that uses a bevel gear,
The input transmission member (3) is a differential case, and the output transmission member (4) is a right or left side gear.

The fact that the two transmission members (3) and (4) on the input and output sides can rotate in the forward and reverse directions relative to each other means that the transmission member (3) on the input side depends on the rotation speed of the transmission member (4) on the output side. It refers to the forward or reverse rotation that occurs relatively between them.

The spring (5) for pressing the direction switching valve (7) to the side surface (14) of the rotor (8) may be, for example, a coil spring or a disc spring.

The stopper (16) that locks the forward / reverse rotation of the direction switching valve (7) at a constant angle is provided, for example, between the side surface of the direction switching valve (7) and the side surface (11) of the pump case (10). It is preferable to form a circular arc-shaped long groove (22) on the other side and project a knock pin (23) that engages with the long groove (22) on the other side.

The suction ports (17) and (18) of the switching valve (7) are formed at positions communicating with the suction holes (12) of the pump case (10) at the time when the suction ports (17) and (18) are stopped by rotating forward or backward at a constant angle. One of the suction ports (17) (18) is connected to the suction port (1
The working fluid (5) can be inhaled by communicating with (2). At that time, one of the discharge ports (35) (3
5) coincides with the discharge hole (13) of the case (10) so that the working fluid (5) can be discharged toward the pump.

[Action]

I First, when the vehicle is traveling straight or turning at a high speed (turning radius is large), between the input-side transmission member (3) and the output-side transmission member (4) to the front / rear or left / right wheels. The rotation difference does not occur or is small. Further, when the vehicle turns at a low speed (turning radius is small), a large rotation difference occurs, but the vane does not fly out due to centrifugal force, so the vane pump (6) does not operate.

Therefore, in the differential limiting mechanism of the present invention, the rotor (8) with vanes provided on the transmission member (3) on the input side and the pump case (10) provided on the transmission member (4) on the output side are provided. The vane pump (6) will either not be differential or will only operate slowly.

Therefore, the working fluid (5) does not press the multi-plate clutch (2) or does not have a pressure enough to generate a frictional force in the multi-plate clutch (2). The device is not limited to differentials.

II Next, when one of the front / rear or left / right wheels of the vehicle idles in a place with a small friction coefficient such as a dirt road and a frozen road, when one of the input side transmission member (3) and the output side transmission A large difference in rotation occurs between the members (4). Therefore, in the differential limiting mechanism, due to the rotation difference between the vaned rotor (8) provided in the input side transmission member (3) and the pump case (10) in the one output side transmission member (4), the rotation difference is caused. The vane pump (6) is activated.

That is, the rotation direction of the transmission member (3) on the input side is constant,
The transmission member (4) on the output side rotates faster or slower than the input shaft. Therefore, depending on the number of rotations of the transmission member (4) on the output side, a normal or reverse rotation is relatively generated between the transmission members (3) and (4). At this time, since the direction switching valve (7) is pressed against the input side rotor (8) by the spring (15), it always rotates in the same direction as the rotor (8). Then, after rotating by a certain angle, the switching valve (7) is locked by the stopper (16) with the pump case (10) and stopped.

In the above case, on the side where the volume of the vane pump chamber (29) increases (fluid suction side) depending on the rotation difference between the pump case (10) and the vane rotor (8), the suction hole of the pump case (10). Either the suction port (17) or (18) of the directional control valve (7) coincides with (12) (see FIG. 3 for forward rotation and FIG. 4 for reverse rotation). 5) can be sucked into the pump chamber (29).

At that time, on the side where the volume of the vane pump chamber (29) becomes smaller (fluid discharge side), the discharge hole (13) of the case (10) and the discharge port (35) of the direction switching valve (7) are in communication. Therefore (see FIG. 3 for forward rotation and FIG. 4 for reverse rotation), the working fluid (5) in the pump (6) can be discharged from the discharge hole (13). The discharged working fluid (5) is sent toward the pinton and becomes a force for pressing the multi-plate clutch (2), and a large frictional force corresponding to the rotation difference is generated to generate a differential limiting force.

As described above, when the rotational speed of the transmission member (4) on the output side changes, the rotor (8) on the input side rotates in the opposite direction relative to the pump case (10) on the output side. Since the direction switching valve (7) is pressed against the rotor (8) by the spring (15), it automatically and instantaneously follows the rotor (8) and switches to reverse rotation. Working fluid (5) during this reverse rotation
Is sucked into the pump (6) automatically and instantly from the suction port (18) on the reverse rotation side, and is discharged from the discharge hole (13) to the outside of the pump (6) to produce the multi-plate clutch (2). By pressing, the differential limiting force according to the running state is automatically and instantly exerted.

〔Example〕

The illustrated example shows a case where the differential limiting mechanism of the present invention is provided in a planetary gear type differential device and is used for a center differential.

This planetary gear type differential device has a structure similar to that of a conventionally known planetary gear type center differential. That is, the input shaft (19) is provided with an internal gear (27) which rotates integrally therewith, while the output shaft (21) is provided with a sun gear which is rotatable integrally therewith.

The internal gear (27) and the sun gear are meshed with each other through a multi-stage planetary gear (26), and a planetary gear case provided with a shaft of each planetary gear (26) is provided with a cylindrical portion of the output shaft ( It is rotatable around 21). With this planetary gear type differential device, the wheels differentially rotate on curved roads, bumpy roads, etc., and smooth running is possible.

A pump spindle (25) that rotates integrally with the internal gear (27) is provided as an input side transmission member (3) on the outer periphery of the tubular portion of the planetary gear case of the differential device, as will be described later. On the outer circumference of the spindle (25)
As described later, a pump case (10) is provided as the operating member (4) on the output side.

A chain wheel (20) for the front wheels is integrally provided on the pump case (10), and an internal gear is provided between the pump case (10) and the disc portion of the pump spindle (25). A rotatable multi-disc clutch (2) is provided integrally with (27). (25) is a pump spindle as a transmission member (3) on the input side, and the flange-shaped outer peripheral edge of the pump spindle is hooked by an internal gear (27) of a differential gear using a planetary gear (26) and transferred from the transfer. Receives the rotational force of the input shaft (19).

The vane pump (6) has a rotor (8) fixed to the outer circumference of a pump spindle (25) serving as the input side transmission member,
A pump case (10) serving as an output side transmission member has a large number of vanes (9) that are in sliding contact with the inner peripheral surface of the pump case (10). Like a normal one, the working fluid suction side into the pump chamber (29) and the pinton side. And the working fluid discharge side to.

(10) is a pump case as a transmission member (4) on the output side, which forms a storage chamber (28) for the working fluid (5) and a vane pump chamber (29) on the outer periphery of the pump spindle (25). It has a chain wheel (20) of a chain (30) which is provided and transmits the driving force to the front wheels.

In addition, a suction hole (12) and a discharge hole (1) for the working fluid (5) are provided at target positions in the circumferential direction on the side surface (11) of the pump case (10).
3) has been formed. In addition, on the inner peripheral surface corresponding to the outer peripheral surface of the switching valve (7), at the positions on both sides with the suction hole (12) in between, the suction port (17) of the switching valve (7) stopped after the forward / reverse rotation. Communication groove (34) that can communicate with either one of (18)
(34) are also formed (see FIG. 11).

The direction switching valve (7) has a hollow thin disk shape, and has a side surface (11) on which a suction hole (12) and a discharge hole (13) of the pump case (10) are formed and a side surface of a rotor (8) ( 14), which is interposed between the hollow disk-shaped side faces, and a knock pin () as a stopper (16) projecting on the pump case (10) to stop relative forward / reverse rotation at a constant angle. An arcuate long groove (22) is formed so that the groove (23) can be engaged.

Further, the direction switching valve (7) has a position near the outer periphery thereof,
When the switching valve (7) stops after rotating at a certain angle in the forward / reverse direction, it rotates in the reverse direction with the intake port (17) for the forward rotation at each position corresponding to the intake hole (12) of the case (10). An intake port (18) for use is formed respectively. Further, the switching valve (7)
Groove-shaped discharge ports (35) (35) are formed on both sides of the outer peripheral surface of the case, and one of the suction ports (17) (18) is a suction hole (12) of the case (10). At the same time, the one groove-shaped discharge port (35) communicates with the discharge hole (13) of the case (10) (see FIG. 5). The groove-shaped discharge ports (35) (35) are rotated in the forward or reverse direction to rotate the case (1).
The shape is such that it can communicate with any of the communication grooves (34) (34) of (0).

The spring (15) for pressing the direction switching valve (7) to the side surface (14) of the rotor (8) is a coil spring whose other end is supported by the pump spindle (25). Although the transmission member (3) on the input side is the pump spindle (25) and the transmission member (4) on the output side is the pump case (10) in the above,
It is not limited to that. (32) shows a fluid passage from the discharge hole (13) to the piston (31).

The operating state of the directional control valve in the above embodiment is as follows.

a) First, when the switching valve 7 rotates forward, as shown in FIG. 3, on the side where the volume of the vane pump chamber (29) becomes large, the suction hole (12) of the pump case (10) and the direction switching valve (7). ) One suction port (suction port for normal rotation) (17) matches. Therefore, the working fluid (5) can be sucked from the suction port (12) through the suction port (17), and through the communication groove (34) communicating with the suction port (17), the pump chamber (29).
Filled inside. At this time, the groove-shaped discharge port (35) on this side (the right side in the figure) does not communicate with the discharge hole (13) of the case (10), but communicates with the communication groove (34) to generate the working fluid. (5)
Plays a role of influxing.

On the side where the volume of the vane pump chamber (29) becomes smaller, the groove-shaped discharge port (3) on the other side (left side in the figure) of the switching valve (7).
5) communicates with the discharge hole (13) of the case (10).
Therefore, the working fluid (5) pressurized by the decrease in volume is
It is sent out from the groove-shaped discharge port (35) through the discharge hole (13) toward the pinton (31), and serves as a force for pressing the multi-plate clutch (2) to limit the differential.

b) When the switching valve (7) rotates in the reverse direction, as shown in FIG. 4, on the side where the volume of the vane pump chamber (29) increases, the suction hole (12) of the case (10) and the direction switching valve ( 7) The other suction port (suction port for reverse rotation) (18) coincides, and the working fluid (5) flows from the suction hole (12) through the suction port (18) into the pump chamber (29). Is sucked into the pump chamber (29) through the communication groove (34) communicating with the suction port (18). Also in this case, the groove-shaped discharge port (35) on this side (left side in the figure) is the discharge hole (1) of the case (10).
It does not communicate with 3) but plays a role of allowing the working fluid (5) to flow in through the communication groove (34).

On the side where the volume of the vane pump chamber (29) becomes smaller, the groove-shaped discharge port (3) on the other side (left side in the figure) of the switching valve (7).
5) communicates with the discharge hole (13) of the case (10).
Therefore, the working fluid (5) pressurized by the decrease in volume is
It is sent out from the groove-shaped discharge port (35) through the discharge hole (13) toward the pinton (31), which serves as a force for pressing the multi-plate clutch (2) and limiting the differential.

As described above, when the rotational speed of the transmission member (4) on the output side changes, the rotor (8) on the input side rotates in the opposite direction relative to the pump case (10) on the output side. Since the thin disk-shaped directional control valve (7) is pressed against the rotor (8) by the spring (15), it automatically and instantaneously follows the rotor (8) and switches to reverse rotation, and the forward rotation is changed. It corresponds to reverse rotation.

EFFECTS OF THE INVENTION As is apparent from the above, the differential device with the mechanism for limiting the differential with the multi-plate clutch at the time of relative rotation of the input / output bearing member according to the present invention has a small and simple structure as a whole. Moreover, the differential limiting force can be generated by automatically and instantaneously switching between the suction side and the discharge side of the vane pump according to the running state of the vehicle.

That is, in the conventional differential device, the differential limiting mechanism with a built-in vane pump needs to form a complicated hydraulic circuit in the pump case, which is difficult to manufacture and process. Moreover, four check valves must be provided in the above circuit, which makes the pump case large and heavy, and cannot be mounted on a small vehicle.

On the other hand, in the differential limiting mechanism of the differential device of the present invention, the direction switching valve of the base pump is formed into a disk shape having suction ports at two positions at a constant angle in the circumferential direction, and is pressed against the rotor side by a spring. In addition, the stopper is provided to enable rotation following the rotor and to stop at a constant angle.

Therefore, in the differential limiting mechanism of the present invention, the direction switching valve of the vane pump relatively forwards / reverses at a constant angle with respect to the relative forward / reverse rotation between the two transmission members in the differential gear depending on the running state. By rotating, one of the two suction ports can be automatically and instantly matched with the suction hole of the case. Therefore, the flow of the working fluid can be switched automatically and instantaneously, and the differential limiting force according to the running state can be generated. Moreover, since the structure is simple and small, the differential device using the same can be mounted in a small vehicle.

[Brief description of drawings]

The figure shows a case in which the differential limiting mechanism according to the present invention is provided for a planetary gear type differential device and is used for a center differential. FIG. 1 is a cross-sectional plan view thereof, and FIG. 2 is an enlarged cross-sectional plan view of essential parts. FIG. 3 is a sectional view taken along the line AA of FIG. 2 showing the positional relationship with the pump case when the direction switching valve rotates forward, and FIG. 4 shows the positional relationship with the pump case when the direction switching valve rotates backward. Fig. 2 is a sectional view taken along the line AA, Fig. 5 is a right side view of the directional control valve, Fig. 6 is a left side view of the directional control valve, and Fig. 7 is a sectional view taken along the line BB of Fig. 6. 8 is a sectional view taken along line CC of FIG. 6, FIG. 9 is a sectional view taken along line DD of FIG. 6, 10 is a sectional view taken along line EE of FIG. 6, and 11 is a pump case. Part of the right side view, FIG. 12 is a sectional view taken along line FF in FIG. Drawing reference numeral (1) ... differential device (2) ... multi-plate clutch (3) ... input side transmission member (4) ... output side transmission member (5) ... working fluid, (6) ... … Vane pump (7) …… Direction switching valve, (8) …… Rotor (9) …… Vane, (10) …… Pump case (11) …… Side, (12) …… Suction hole (13) …… Discharge hole, (14) …… Side surface (15) …… Spring, (16) …… Stopper (17) …… Suction port, (18) …… Suction port (19) …… Input side, (21) …… Output shaft (34) …… groove for communication, (35) …… Discharge port

Claims (1)

[Claims] 1. When the input / output shafts (19) (21) rotate relative to each other,
In a differential device (1) with a mechanism for limiting the differential with a multi-plate clutch (2), there are two input / output side rotatable devices in the differential device (1) that are relatively rotatable in forward and reverse directions. A vane pump (6) capable of supplying the working fluid (5) for pressing the multi-plate clutch and a direction switching valve (7) are provided between the transmission members (3) and (4), and the vane pump (6) includes: A rotor (8) having a large number of vanes (9) is provided on the transmission member (3) on the input side, and a pump case (10) on which the vanes (9) can slidably contact the inner peripheral surface is provided on one output side. Is formed on the side surface (11) of the case (10) to form a suction hole (12) and a discharge hole (13) for the working fluid (5). The hollow disk-shaped side surface (11) of the pump case (10) in which the suction hole (12) and the discharge hole (13) are formed and the rotor ( Interposed between the side surface (14) of), the rotor (spring for pressing the side surface (14) of 8) (15)
Is provided with a stopper (16) for stopping the forward / reverse rotation of the switching valve (7) at a constant angle, and the case (10) is sucked when the switching valve (7) is stopped by the forward / reverse rotation. The suction ports (17) and (18) communicating with the suction hole (12) are formed at the positions corresponding to the holes (12), and at the positions corresponding to the discharge holes (13) of the case (10).
By forming the discharge port (35) communicating with the discharge hole (13), the switching valve (7) rotates by a certain angle in accordance with the positive relative rotation of the input / output shafts (19) (21), One of the inlet (17) and the outlet (35) of the switching valve (7) is a case (10).
Communicates with the suction hole (12) and the discharge hole (13) of the switch valve, and the switching valve (7) reversely rotates by a certain angle in accordance with the relative rotation in the opposite direction,
The other suction port (18) and discharge port (35) of the switching valve (7) communicate with the suction hole (12) and discharge hole (13) of the case (10) to limit the differential. A differential limiting mechanism in a differential device characterized by the above.