JPH0612995Y2 - Power transmission device for four-wheel drive vehicle - Google Patents

Description

TECHNICAL FIELD The present invention relates to a power transmission device for a four-wheel drive vehicle.

2. Description of the Related Art As a power transmission device of this type, Japanese Patent Application Laid-Open No. 61-10232
The one shown in No. 6 is known. This device includes a vane pump and a hydraulic control device that controls the discharge hydraulic pressure from the pump. The rotor of the vane pump is connected to the first rotating shaft that transmits the driving force to the front wheels, and the casing is connected to the second rotating shaft that transmits the driving force to the rear wheels, and the vane pump is driven by the difference in rotational speed between them. To be done. Further, the casing is provided with a first suction / discharge port and a second suction / discharge port, and the first suction / discharge port and the second suction / discharge port are provided depending on the relative rotation direction of the rotor and the casing.
The direction in which the oil flows between the suction and discharge ports is switched, and the amount of oil is discharged according to the rotational speed difference between the rotor and the casing. Further, the first suction discharge port and the second suction discharge port of the vane pump are communicated with each other by a communication oil passage, and in this communication oil passage, the control device uses pressure oil or air to discharge from the vane pump. Control hydraulic pressure.
Then, the brake pressure when braking the vehicle, the signal of the load condition of the engine, the throttle opening, the steering angle of the steering wheel,
Vehicle speed, steering hydraulic pressure generated when steering power steering,
By inputting the acceleration signal from the acceleration sensor, the computer controls the discharge hydraulic pressure of the vane pump caused by the difference in the rotational speed of the front and rear wheels, and the power transmission amount to the front and rear wheels is changed according to the running condition and distributed appropriately.

However, in this power transmission device, the rotor of the vane pump and the casing are both rotating at high speed, and it is necessary to supply pressure oil or air for controlling the discharge hydraulic pressure to the rotating body. The problem arises. That is, it is necessary to connect a fixed pipe for supplying pressure oil or air to the rotation center of the rotating body, which requires a high degree of sealing technology. Therefore, it is difficult to transmit the controlled hydraulic pressure without leaking, and there is a problem in reliability. Further, the mounting portion of the fixed pipe and the rotating body is required to withstand the temperature change, the vibration and the abrasion due to the sliding, to ensure the pressure resistance and reduce the friction loss, so that the structure is complicated and the cost becomes expensive.

An object of the present invention is to provide a power transmission device for a four-wheel drive vehicle that solves the above problems.

The device according to the invention comprises a first rotary shaft connected to a first rotary shaft for transmitting a driving force to a front wheel.
Driven by the difference in rotational speed between the first rotating body and the second rotating body connected to the second rotating shaft that transmits the driving force to the rear wheel, and the relative rotation direction of the first rotating body and the second rotating body. Is used to switch the direction of oil flow between the first suction / discharge port and the second suction / discharge port, and to discharge the amount of oil according to the difference in rotational speed between the first rotating body and the second rotating body. Power of a four-wheel drive vehicle including a pump and a hydraulic control device that controls the hydraulic pressure discharged from the hydraulic pump in a communication oil passage that connects the first suction discharge port and the second suction discharge port of the hydraulic pump In the transmission device, the first suction / discharge port and the second suction / discharge port of the hydraulic pump, and the communication oil passages for these are provided in one of the rotating bodies, and the hydraulic control device controls the rotation of the one side. It is attached to the body so that it can move in parallel with it and in the axial direction. And a sliding member that faces the communicating oil passage, a sliding member that is attached to the one rotating body concentrically and axially, and is connected to the spool, and the sliding member. It is characterized in that it is provided with a control member which is rotatably mounted on the shaft and is mounted on the fixed side, and a moving device which moves the control member in the axial direction.

By moving the control member with the moving device, the sliding member moves with respect to the rotating body, whereby the spool moves accurately by the same amount as the control member. Therefore, the discharge hydraulic pressure from the hydraulic pump is accurately controlled, and the reliability is high. Further, the rotation of the rotating body is absorbed by the bearing between the sliding member and the control member. Further, since it is only necessary to provide a bearing between the sliding member on the rotating side and the control member on the stationary side, there is no need to connect the stationary pipe and the rotating body as in the conventional case, so the structure is simple and the cost is low. .

Embodiment FIG. 1 shows the first embodiment, and the power transmission system comprises a vane pump (10) and a hydraulic control device (11) for controlling the discharge hydraulic pressure from this pump (10). FIG. 2 shows the circuit layout of the vane pump (10).

The vane pump (10) includes a casing (12) and a casing (1
2) a cam ring (13) fixed inside, a rotor (14) arranged inside the cam ring (13) inside the casing (12), and a plurality of vanes (15) attached to the rotor (14). It consists of The rotor (14) is connected to the first rotating shaft (16) that transmits the driving force to the front wheels, and the casing (12) is connected to the second rotating shaft (17) that transmits the driving force to the rear wheels. The pump (10) is driven by these rotational speed differences. A shaft portion (18) is formed on one end surface of the casing (12), and the shaft portion (18)
Are rotatably supported by the fixed housing (20) via bearings (19). Although not shown, the rotary shafts (16) and (17) are also rotatably supported at appropriate positions on the housing (20).
Two first suction and discharge ports (21a) and (21b) are formed at substantially diagonal positions of the casing (12), and two second suction and discharge oil passages (22a) (22a) ( 22b) has been formed. The direction of oil flow between the first suction / discharge ports (21a) (21b) and the second suction / discharge ports (22a) (22b) is cut by the relative rotation direction of the rotor (14) and the casing (12). Replace That is, when the rotor (14) rotates relative to the casing (12) in the clockwise direction in FIG. 2, the first suction / discharge ports (21a) (21b) serve as the suction port and the second suction / discharge port (22a). ) (22b) becomes the discharge port. On the contrary, when the rotor (14) relatively rotates counterclockwise in the figure, the second suction / discharge ports (22a) (22b) are discharged to the suction ports and the first suction / discharge ports (21a) (21b) are discharged. Become an exit. Also, pump (1
The amount of oil discharged from (0) is proportional to the rotational speed difference between the rotor (14) and the casing (12).

The first suction and discharge ports (21a) and (21b) are communicated with each other by the first oil passage (23), and the second suction and discharge ports (22a) and (22b) are connected to the second oil passage (24).
Is in communication with. In addition, the first oil passage (23) and the second oil passage
(24) is connected by the discharge oil passage (25), and this oil passage (2
5) is connected to the oil sump (26). A spool (27) of a hydraulic control device (11), which will be described later, faces an intermediate portion of the discharge oil passage (25), and the spool (27) of the discharge oil passage (25) is located at a first position.
From the oil sump (26) to the first oil passage (23) on the oil passage (23) side
The check valve (28) that allows only the oil flow to the second oil passage
A check valve (29) that allows only the flow of oil from the oil sump (26) to the second oil passage (24) is provided in the portion on the (24) side. The first oil passage (23) and the second oil passage (24) are connected to the switching oil passage (3
It is communicated with a portion of the discharge oil passageway (25) where the spool (27) is provided via (0). The switching oil passage (30) includes two switching check valves (31) that allow only the outflow of oil from the first oil passage (23) and the second oil passage (24) to the discharge oil passage (25). ) (32) are provided opposite to each other.

The power transmission device described above is a hydraulic control device to be described below.
Except for (11) and its related parts, JP-A-61-10
Since it is the same as that described in No. 2326, further detailed description will be omitted.

The oil passages (23), (24), (25) and (30) are all formed in the casing (12). In the embodiment of FIG. 1, two sets of the discharge oil passage (25) and the switching oil passage (30) are provided, and the spool (27) is provided in each of them. The spool (27) is parallel to the axis (A) of the casing (12) and
It is slidably inserted into (12) from its one end surface in the axial direction, and its tip (27a) is connected to the discharge oil passage (25) and the switching oil passage (3
0). Also, spool (27) and casing (12)
An O-ring (33) is provided between the two. Casing (1
A cylindrical sliding member (34) is fitted on the shaft portion (18) of (2) so as to be slidable in the direction of the axis (A), and a flange (35) formed at one end of the sliding member (34) is fitted with a retaining ring ( By (36), it is fixed to the end (27b) of the spool (27) projecting to the outside of the casing (12) so as not to move in the axial direction. A stepped cylindrical control member (37) is rotatably mounted around the other end of the sliding member (34) via a bearing (38). Inner ring of this bearing (38)
(38a) is fixed to the sliding member (34) by the retaining ring (39) so as not to move axially, and the outer ring (38b) is prevented from moving axially to the control member (37) by the retaining ring (40). It is fixed to. A screw (41) is formed at one end of the control member (37), and this is formed in the annular recess (42) of the housing (20), and thus is screwed into the screw (43). Also, the control member
A gear (44) is formed on the outer peripheral surface of the intermediate portion of (37). On the other hand, the housing (20) is provided with a control stepping motor (45), and the worm (46) attached thereto meshes with the gear (44) of the control member (37).

When the worm (46) is rotated by the rotation of the motor (45), the control member (37) is rotated via the gear (44) meshing with the worm (46). When the control member (37) rotates, the control member (37) moves in the axial direction by the action of the male screw (41) of the control member (37) and the female screw (43) of the housing (20) meshing with the male screw (41). Both of these movements are proportional to the amount of rotation of the motor (45). Control member
The movement of (37) is transmitted to the sliding member (34) via the bearing (38), and the sliding member (34) and the control member (37) with respect to the shaft portion (18) of the casing (12). Move axially by the same amount. Then, the movement of the sliding member (34) causes the spool (27) to move in the casing (12) in the axial direction by the same amount as the control member (37), whereby the discharge hydraulic pressure from the pump (10) is increased. Controlled.

Others are the same as in the case of Japanese Patent Application No. 61-102326,
By controlling the motor (45) according to the running conditions,
It is possible to realize the optimum four-wheel drive state by adjusting the power transmission force and performing appropriate power distribution.

FIG. 3 shows the second embodiment, and the parts corresponding to those of the first embodiment are designated by the same reference numerals.

In the case of the second embodiment, the control member (37) has a substantially cylindrical shape, and the flange (47) is formed in the middle portion thereof. Then, this flange (47) is provided with a stepped hole (4
8) Large diameter part (48a) has the same hole on the side opposite the bearing (38).
It is slidably fitted in the small diameter portion (48b) of (48). O-rings (49) (50) between the large diameter part (48a) of the hole (48) and the flange (47) and between the small diameter part (48b) and the control member (37).
The stepped portion (48c) of the stepped hole (48) and the control member
An annular oil chamber (51) is formed between the flanges (47) of (37). Further, the housing (20) has an oil supply / discharge passage (52) for the oil chamber (51). Large diameter part of stepped hole (48) (48
An annular stopper (53) is fixed to the end of (a), and the control member (3) is interposed between this stopper (53) and the flange (47) of the control member (37).
A compression coil spring (54) for urging 7) to the right in FIG. 3 is provided. Further, the casing (12) and the sliding member (34)
A compression coil spring (55) for urging the sliding member (34) to the right in FIG. 3 is also provided between them.

By increasing the oil pressure in the oil chamber (51), the control member (37)
Moves to the left side in FIG. 3 against the springs (54) and (55), and when the hydraulic pressure in the oil chamber (51) is lowered, the control member (37) causes the spring (54) to move.
It moves to the right side of FIG. 3 by (55). By moving the control member (37) in the axial direction in this manner, the spool (27) is moved to the control member (37) as in the case of the first embodiment.
By the same amount in the same direction as the pump (1
The discharge hydraulic pressure from 0) is controlled.

In the above embodiment, the vane pump is used as the hydraulic pump, but other types of pumps such as a plunger pump and a trochoid pump can be used. Further, the configuration of the other parts of the power transmission device is not necessarily limited to that of the above-described embodiment, and can be changed as appropriate.

Effect of the Invention According to the power transmission device of the present invention, by moving the control member as described above, the spool can be moved reliably and accurately, and the discharge hydraulic pressure from the hydraulic pump can be accurately controlled. Yes, it is reliable. Further, since it is only necessary to provide a bearing between the sliding member on the rotating side and the control member on the stationary side, there is no need to connect the stationary pipe and the rotating body as in the conventional case, so the structure is simple and the cost is low. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cutaway side view of a power transmission device showing a first embodiment of the present invention, FIG. 2 is a drawing showing a hydraulic circuit arrangement of a portion of a vane pump of FIG. 1, FIG. 3 is a drawing corresponding to FIG. 1 showing a second embodiment of the present invention. (10) …… Vane pump, (11) …… Hydraulic control device, (12)…
… Casing, (14) …… Rotor, (16) …… First rotary shaft, (17) …… Second rotary shaft, (20) …… Fixed housing,
(21a) (21b) …… first suction / discharge port, (22a) (22b) …… second
Suction and discharge port of (25) …… Discharge oil passage, (27) …… Spool,
(30) …… Switching oil passage, (34) …… Sliding member, (37) …… Control member, (45) …… Motor.

Claims (1)

[Scope of utility model registration request] 1. A first rotating body connected to a first rotating shaft for transmitting a driving force to front wheels, and a second rotating body connected to a second rotating shaft for transmitting a driving force to rear wheels. Driven by the difference in rotational speed between the first rotary body and the second rotary body, the direction of oil flow between the first suction discharge port and the second suction discharge port is switched according to the relative rotation direction of the first rotary body and the second rotary body. A hydraulic pump that discharges an amount of oil according to the difference in rotational speed between the first rotary body and the second rotary body, and a communication oil passage that connects the first suction discharge port and the second suction discharge port of this hydraulic pump. In a power transmission device for a four-wheel drive vehicle, comprising: a hydraulic control device that controls the discharge hydraulic pressure from the hydraulic pump in the first pump, the first suction / discharge port and the second suction / discharge port of the hydraulic pump, and a communication oil passage for these. Is provided on one of the rotating bodies, and the hydraulic control device is A spool mounted on the one rotating body so as to be movable in the axial direction in parallel with the rotating body and facing the communicating oil passage, and to be concentrically and axially movable to the one rotating body. A sliding member attached and connected to the spool, a control member rotatably attached to the sliding member via a bearing, and attached to the fixed side, and a movement for moving the control member in the axial direction. A power transmission device for a four-wheel drive vehicle, comprising: