JPH0721934Y2 - Drive coupling device for four-wheel drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a four-wheel drive drive coupling device that utilizes the hydraulic pressure generated by a vane pump as a means for transmitting a driving force between front and rear wheels.

[Prior art]

A four-wheel drive vehicle not only provides high running stability on special road conditions such as snowy roads and gravel roads, but also has excellent stability on normal road surfaces during acceleration / deceleration and high-speed running. Therefore, in recent years, it has been particularly spotlighted as a device that can realize comfortable running regardless of the road surface condition and the running condition. As such a four-wheel drive vehicle,
A drive connecting device that distributes a driving force according to the rotational speed difference between the rear wheels is provided in the middle of the transmission shaft between the front and rear wheels, which is the mainstream. As one type, there is a hydraulic pump, in particular, one that utilizes the generated hydraulic pressure of a vane pump that is easy to reduce in size and weight and has excellent durability.

The vane pump has a short cylindrical rotor that is equipped with a plurality of flat plate-shaped vanes that are arranged substantially equidistantly in the circumferential direction so as to be able to advance and retreat in the radial direction, and a cam ring that forms an eccentric annular A side plate is attached to each of the side plates, and a casing having a space surrounded by the side plate is formed therein. The rotor is coaxially and rotatably accommodated in the inner space of the casing, and the outer peripheral surface of the rotor and the cam ring. A plurality of pump chambers surrounded by these and the side surfaces of both side plates are formed between the inner peripheral surface and the inner peripheral surface, and the oil introduced into each separate pump chamber is slidably brought into contact with the inner peripheral surface of the cam ring. The drive coupling device using the vane pump has a known structure in which it is sealed between adjacent vanes and is rotated by the rotation of the rotor to increase the pressure. The rotor On the other hand, the casing is coaxially fixed to the shaft body connected to the other so that relative rotation corresponding to the difference in rotational speed between the front and rear wheels is generated between the rotor and the casing. The hydraulic pressure is generated according to the relative rotation speed, and the driving force is transmitted between the rotor and the casing by the frictional force acting in the direction of suppressing the relative rotation.

This drive coupling device is disclosed in Japanese Patent Application Laid-Open No. 1-153335 by the present applicant.
As described in Japanese Patent Laid-Open Publication No. JP-A-2003-242, pressure oil is supplied to each of the separate pump chambers through a valve fixed to a side plate on one side of an oil tank, and each vane penetrates through the front and back sides. Similarly, small squeezing holes are formed, and a part of the oil that is pressurized in the sealed space formed between the vanes is adjacent to the low pressure side of the space, that is, the upstream side in the relative rotation direction of the rotor. In the sealed space of the above, the throttle holes are made to flow through and leak out, and the oil delivered from the pump chamber is introduced into the bottom of the storage groove in which each vane is inserted, and each vane is removed. After pressing in the advancing direction and pressing these tips against the inner peripheral surface of the cam ring, it leaks out through a small gap between the side surface of the rotor and the side plate and returns to the low-pressure oil tank. I am supposed to do it. That is, the hydraulic pressure generated in the pump chamber in response to the relative rotation generated between the rotor and the casing resists the flow resistance in the gap between the throttle hole and the rotor and the side plate, mainly against the flow resistance of the former. It is supposed to occur.

[Problems to be Solved by the Invention] When an automobile accelerates or decelerates and a large load is applied to one of the front and rear wheels, a large rotational speed difference occurs between the front and rear wheels. When such a large rotation speed difference occurs,
The relative rotation speed between the rotor and the casing is high, and the time interval between suction and discharge of the pressure oil in the pump chamber is short, which requires a large flow rate of pressure oil.

However, in the conventional drive coupling device as described above, since the pressure oil is fed to each of the separate pump chambers by a single path, the maximum feed amount of the pressure oil is small, and the large amount of pressure oil is generated. When it becomes necessary, the flow rate of the pressure oil tends to be less than the required flow rate, which may cause cavitation in the pressure oil. When cavitation occurs in the pressure oil in this way, when the pressure oil is pressurized in the pump chamber, the bubbles in the pressure oil disappear, so the pressure in the pump chamber is kept low, and a sufficient driving force is thereby obtained. However, there was a problem that the transmission was not performed between the front and rear wheels.

The present invention has been made in view of such circumstances, and by providing a plurality of pressure oil supply paths to the pump chamber, the supply flow rate of the pressure oil is increased to suppress the occurrence of cavitation, and even during acceleration / deceleration. An object of the present invention is to provide a four-wheel drive drive coupling device capable of transmitting a sufficient driving force between the front and rear wheels.

[Means for Solving the Problems]

A drive connecting device for four-wheel drive according to the present invention comprises a plurality of plate-shaped vanes each having a throttle hole penetrating to the front and back so as to be able to advance and retreat in the radial direction, and a cylinder that rotates in conjunction with one of the front and rear wheels. -Shaped rotor and a casing that rotates in conjunction with the other and has side plates mounted on both sides of a cam ring having an uneven thickness annular shape, respectively, the outer peripheral surface of the rotor, the inner peripheral surface of the cam ring, and the side plates on both sides. The rotor is housed in a casing so as to form a plurality of pump chambers surrounded by the side surface, and a vane pump is formed, pressure oil is sent to the pump chambers, and it is generated against the flow resistance of the throttle hole. In the four-wheel drive drive connection device for connecting the front and rear wheels by the hydraulic pressure, the one side plate is provided with a plurality of suction oil passages that respectively communicate the plurality of pump chambers with the oil storage portion, and the other is provided. of The id plate is provided with a plurality of discharge oil passages that individually communicate the plurality of pump chambers and the oil storage portion, and a plurality of communication oil passages that divide the discharge oil passages in the middle and communicate with the oil storage portion. A suction check valve that allows only the inflow from the oil reservoir to the pump chamber is provided for each of the plurality of suction oil passages and each of the plurality of communication oil passages, and the pump chamber is provided for each of the plurality of discharge oil passages. A discharge check valve is provided which allows only the outflow to the oil reservoir.

[Action]

According to the present invention, one side plate is provided with a suction oil passage for pressure oil to the pump chamber, and the other side plate is provided with a discharge oil passage and a communication oil passage that share a part of the oil passage. Since the pressure oil can be sucked in through the suction oil passage and the communication oil passage, it becomes possible to provide a sufficient margin for the pressure oil supply amount, and cavitation caused by the shortage of the supplied pressure oil, etc. It is possible to prevent inconvenience, and a separate check valve is provided for each of the plurality of suction oil passages, discharge oil passages, and communication oil passages so that they can communicate with the oil reservoir, so the capacity of the check valve itself can be small and high. Responsiveness can be obtained.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings showing an embodiment thereof. FIG. 1 is a longitudinal sectional view of a drive connecting device for four-wheel drive (hereinafter referred to as the device of the present invention) according to the present invention, and FIG. 2 is II-I of FIG.
It is a cross-sectional view taken along the line I.

In the figure, 1 is an input shaft that rotates in conjunction with one of the front and rear wheels, and 2 is an output shaft that rotates in conjunction with the other.
In the proposed device, due to the pressure generated by the vane pump 3 interposed between the input shaft 1 and the output shaft 2, the rotational speed difference between the two shafts, that is, the rotational speed difference generated between the front and rear wheels, The driving force is transmitted from the input shaft 1 to the output shaft 2.
In a FR-based four-wheel drive vehicle, the input shaft 1 is connected to the rear wheel, which is the main drive wheel, or the engine, which is the drive source,
It goes without saying that the output shaft 2 is connected to the front wheels, and the driving force is transmitted from the rear wheels to the front wheels via the device of the present invention.

In the vane pump 3, a plurality of storage grooves 30b, 30b ... Having a predetermined depth in the radial direction are formed in a short cylindrical body in a substantially equal arrangement in the circumferential direction, and the storage grooves 30b, 30b. In the state of being urged outward in the radial direction by the pair of coil springs 30c, 30c ...
Side plates 32 and 33 are fixed to both sides of a rotor 30 having slidably inserted vanes 30a, 30a ... Is a main component.

The cam ring 31 is provided in a circle having a diameter slightly larger than the outer diameter of the rotor 30 by equidistantly arranging three concave portions in the circumferential direction, and forming a hollow portion 31a having an axial sectional shape as shown in FIG. It is a member formed at the axial center position and having an axial length dimension substantially equal to that of the rotor 30, and the side plates 32, 33 both have bearing holes for the rotor shaft 36 described later at the axial center positions. ,
The former is a thin-walled member, and the latter is a thick-walled hollow disk-shaped member. These side plates 32, 33 are attached to the cam ring 31.
Is positioned coaxially with both sides of the side plate 32 on the side opposite to the cam ring 31 of the side plate 32 and coaxially with them, and a short cylinder is connected to one side of the thin disk. Along with the shaft sealing member 34 that is installed, the shaft sealing member 34, the side plate 32, the cam ring 31 are penetrated in this order, and a plurality of fixing bolts 35 that are screwed into respective screw holes (not shown) formed in the side plate 33. , 35 ... Are integrally connected to form a casing of the vane pump 3. The output shaft 2 has a disc-shaped flange 20 formed at the end thereof.
Side plate 33 with a plurality of fixing bolts 21, 21 ...
Is fixed to the casing on the side opposite to the cam ring 31 and is coaxially fixed to the casing. The casing rotates around its axis in response to the rotation of the output shaft 2, that is, the rotation of the front wheel. Yes.

As shown in FIG. 1, on the outside of the casing, a part of the outer periphery of the side plate 33 and the outer periphery of the cylindrical portion of the shaft sealing member 34 are externally fitted, and a surrounding wall member 38 having a thin tubular shape is mounted. Yes, the operating oil of the vane pump 3 is the same as the surrounding member 38,
It is enclosed in an oil tank T which is an oil storage portion formed in an annular shape with the outer peripheral surface of the casing.

The rotor 30 is inserted in the space surrounded by the cavity 31a of the cam ring 31 and the side plates 32, 33,
A rotor shaft 36 supported by needle roller bearings 32a and ball bearings 33a, which are fixedly fitted in the supporting holes of the side plates 32 and 33, respectively, are externally fitted between the two bearing positions, and are spline-coupled with the bearing shafts. I am allowed. The outer circumference of the rotor shaft 36 is sealed by an oil seal 34a and an X ring 34b mounted on the inner circumference of the cylindrical portion of the shaft sealing member 34, and the rotor shaft 36 is projected to the side plate 32 side by an appropriate length. The connecting flange 37 formed in the above is fixed to the disc-shaped flange 10 formed at the end of the input shaft 1 by a plurality of fixing bolts 11, 11 ,.
It is coaxially connected to the input shaft 1. Thus, the rotor 30
Is connected to the input shaft 1 through the rotor shaft 36,
The rotation of the rear wheel, that is, the rotation of the rear wheel, rotates about its axis.

As described above, between the outer peripheral surface of the rotor 30 inserted in the casing and the inner peripheral surface of the hollow portion 31a of the cam ring 31, the two surfaces, the side plates 32, The three pump chambers 4 which are surrounded by the side surface of 33 and have a modified crescent-shaped axial cross-sectional shape as shown in FIG.
0, 40, 40 are formed, and in each pump chamber 40, a pair of suction ports 40a, 40a (which are located at both ends of the crescent moon and open to the side plate 32 side) are shown in FIG. The suction port located on the upstream side in the rotation direction is shown as 40a ₁ , and the suction port located on the downstream side is shown as 40a _{2. The} same applies hereinafter), and a pair of discharge ports 40b, 40b (first at the side plate 33 side). Two
In the figure, the discharge port located on the upstream side in the relative rotation direction is 40b ₁ ,
The outlet located on the downstream side is shown as 40b ₂ . The same shall apply hereinafter) are formed respectively. Three pump rooms 40,40,40
The respective suction ports 40a, 40a ... Of the respective first suction check valves 41, 41, which are fixed to the side plate 32 so as to correspond to their forming positions and allow only the inflow into the pump chamber 40,
An annular oil chamber 42 formed in such a manner that the inlet portions of the check valves 41, 41 ... Are communicated with the contact surface of the shaft sealing member 34 with the side plate 32, and the disc portion of the shaft sealing member 34 has a thickness. Are connected to the oil tank T by a suction oil passage 43 formed so as to penetrate in the direction, while the discharge ports 40b, 40b ... Have one end opened at these formation positions and are folded inward in the radial direction. The separate oil discharge passages 44, 4 formed on the side plate 33.
4 and the respective discharge check valves 4 that are fixedly provided in the middle of the oil passages 44, 44 ... and allow only the outflow from the pump chamber 40.
An annular groove 46 formed on the side surface of the rotor 30 via 5,45.
It is in communication with. As shown in FIG. 2, the annular groove 46 is formed in such a manner that the bottom portions of the storage grooves 30b, 30b ... Are communicated with each other. Further, the discharge ports 40b, 40b ...
The outlets of the second suction check valves 49, 49, which are fixed to the side plate 33 and have their inlets communicated with the oil tank T, are communicated with the discharge oil passages 44, 44. , The second suction check valves 49, 49 ... Only when the vane pump 3 is sucking,
The pressure oil in the oil tank T is discharged through the discharge oil passages 44, 44 ...
It is sent to the pump chamber 40 from 0b. Also the side plate
The annular space between the bearing holes of 32 and the rotor shaft 36 is a bearing member.
By the communication hole 47 that penetrates the cylindrical portion of 34 in and out,
An annular space between the bearing hole of the side plate 33 and the rotor shaft 36 is provided with a communication hole 48 that penetrates the side plate 33 in the radial direction.
The oil filled in the oil tank T is introduced to lubricate the needle roller bearing 32a and the ball bearing 33a.

Thus, the pressure oil delivered from the discharge port 40b is introduced to the bottom of the storage grooves 30b, 30b ... Through the separate discharge oil passages 44 and the annular groove 46, and the coil springs 30c, 30c ... Synergistically with the urging force of the blades, the vanes 30a, 30a ... are pressed outward in the radial direction, passing through a slight gap between the side surfaces of the rotor 30 and the side surfaces of the side plates 32, 33. And leaks into the bearing hole, passes through the communication holes 47 and 48, and then reaches the oil tank T.
Reflux to.

As shown in FIG. 1, each of the vanes 30a, 30a ... Has a throttle hole 5 formed at the center in the width direction near the tips thereof. The throttle hole 5 forms a through hole 50 having an extremely small diameter so as to penetrate the vane 30a in the thickness direction, and a conical chamfered portion 51 which is substantially concentric with the through hole 50 is continuously provided on one side of the through hole 50. 2 which flows through the throttle hole 5 as described later.
It has a shape that gives different flow resistance to the directional flow. In the throttle hole 5, the flow gradually flows into the through hole 50 through the chamfered portion 51 and gradually flows out from the opening on the other side, and then directly flows into the extremely small through hole 50 to gradually expand the diameter. There is a flow that flows out through the chamfered portion 51. In the former case, since the inflow loss is small, the flow resistance is substantially the addition value of the friction loss in the through hole 50 and the outflow loss, whereas in the latter case, the addition value is Loss and chamfer due to inflow into extra-fine through hole 50
The flow resistance of the former is much smaller than that of the latter, since it is the sum of the loss due to the diversion at 51.

The operation of the device of the present invention configured as described above will be described below. When there is no difference in rotational speed between the input shaft 1 and the output shaft 2, relative rotation does not occur between the rotor 30 interlockingly rotating with the former and the cam ring 31 interlockingly rotating with the latter, and each pump chamber 40, The oil in 40 only rotates with the rotation of the rotor 30 and the cam ring 31, no hydraulic pressure is generated, and the driving force is not transmitted from the input shaft 1 to the output shaft 2. This corresponds to the case where ideal straight running is performed at a constant speed, but such a state rarely occurs during actual running, and the input shaft 1 and the output shaft 2 are In between
There is always some difference in rotational speed, especially when one of the front and rear wheels is idling, or during acceleration or deceleration.
When a large load acts on one of the rear wheels, a large rotational speed difference occurs. When the rotational speed difference is generated in this manner, relative rotation occurs between the rotor 30 and the cam ring 31 as indicated by an arrow a in FIG. 2, and the oil in the oil tank T is
It is introduced into the pump chamber 40 through the suction oil passage 43, the first suction check valve 41, and the second suction check valve 49 from the suction port 40a and the discharge port 40b which are open on the upstream side in the relative rotation direction. And this oil is made up of two vanes next to each other.
The rotor 30 is sealed in a space surrounded by 30a and 30a, the outer peripheral surface of the rotor 30, the inner peripheral surface of the cam ring 31, and the side plates 32 and 33, and the rotor 30 is relatively rotated. When the pressure of the oil in the pump chamber 40 is increased by being rotated in the direction, the oil is discharged from the discharge port 40b ₂ opening in the pump chamber 40 on the downstream side in the relative rotation direction. At this time, the second suction check valve 49 communicating with the discharge oil passage 44 is closed by the discharge hydraulic pressure, and the discharged oil passes through the discharge oil passage 44, the discharge check valve 45 and the annular groove 46, and then the storage groove 30b. Cam rings 3 are installed on the bottoms of the vanes 30a, 30b, and inserted into the vanes 30a, 30a.
It works to press against the inner surface of 1. When the rotor 30 is further rotated relatively, the vane 30a is pushed down by the inner peripheral surface of the cam ring 31, and the oil in the storage groove 30b is transferred to the rotor 30.
The needle roller bearing leaks from the gap between the side plate 32 or the side wall of the side plate 33 into the bearing hole maintained at a low pressure.
32a or the ball bearing 33a serves as a lubricant, and flows through the communication hole 47 or 48 to return to the oil tank T.

As described above, the oil introduced into the pump chamber 40 and sealed in the space formed between the two adjacent vanes 30a, 30a is rotated by the relative rotation and the pressure is increased. ,
A part of the gas flows through the throttle hole 5 formed in the one vane 30a on the upstream side in the relative rotation direction, leaks into the same space adjacent to the above space and in a lower pressure state than this, and the rest is ,
Along with the oil leaking from the throttle hole 5 of the other vane 30a into the space, it passes through the discharge oil passage 44, the discharge check valve 45, and the annular groove 46, passes through the gap between the rotor 30 and the side plates 32, 33, and is low pressure. Leaks to the department. Therefore, the level of the generated hydraulic pressure inside the pump chamber 40 corresponds to the sum of the flow resistance in the throttle hole 5 and the flow resistance in the gap. On the other hand, when the hydraulic pressure is generated in the pump chamber 40 in this way, a frictional force corresponding to the hydraulic pressure acts between the outer peripheral surface of the rotor 30 and the inner peripheral surface of the cam ring 31 in a direction of suppressing the relative rotation. , Rotor
Torque is transmitted between 30 and the casing, that is, between the input shaft 1 and the output shaft 2, and the four-wheel drive state is realized.
Therefore, the magnitude of the transmission torque from the input shaft 1 to the output shaft 2 corresponds to the level of the hydraulic pressure in the pump chamber 40, and the throttle hole 5
And the sum of the flow resistances in the gap.

The direction of relative rotation of the rotor 30 with respect to the casing is determined by which of the rotational speed of the input shaft 1 and the rotational speed of the output shaft 2 is higher. When the rotational speed of the input shaft 1 is high, The relative rotation is based on the input shaft 1 and the output shaft 2.
Occurs in the same direction as the rotation direction of the rotor 30 and the casing, and the rotation speed of the output shaft 2 is high,
The relative rotation likewise occurs in opposite directions. When the former is set to the normal rotation and the latter is set to the reverse rotation, the vanes 30a, 30a ... Are mounted so that the chamfered portion 51 is located on the high pressure side during the reverse rotation, that is, on the downstream side in the relative rotation direction. This suppresses the driving force transmitted to the front wheels to a low level during turning traveling in which the rotational speed of the front wheels is high, and in the normal traveling
This is so that sufficient transmission torque can be obtained when a difference in rotational speed occurs between the rear wheels.

In this device, the side plate 32 has first suction check valves 41, 41 ..., and the side plate 33 has second suction check valves 49, 41.
49 are fixed respectively, and when the vane pump 3 is sucking, the pressure oil can be sucked into the pump chamber 40 through these valves so that a large amount of pressure oil can be sent to the pump chamber 40.
When a large flow rate of pressure oil is required, such as during acceleration / deceleration, where the difference in rotational speed between the front and rear wheels becomes large, pressure oil can be supplied without a shortage, and sufficient pressure oil can be supplied between the front and rear wheels. The driving force is transmitted.

Further, by adding more suction check valves to the pump chamber 40 than in the conventional device, the capacity of each suction check valve can be made smaller than that of the conventional device, and each suction check valve can be miniaturized. This also allows the drive coupling to be miniaturized.

〔effect〕

As described above, in the device of the present invention, one side plate is provided with a suction oil passage for pressure oil to the pump chamber, and the other side plate is provided with a discharge oil passage and a communicating oil passage sharing a part of the oil passage. Since the pressure oil can be sucked into the pump chamber through the suction oil passage and the communication oil passage, it is possible to provide a sufficient margin for the pressure oil supply amount, which is caused by the shortage of the pressure oil supply. Inconveniences such as cavitation can be prevented.

In addition, a check valve is provided for each of the plurality of suction oil passages, discharge oil passages, and communication oil passages so that the check valves can communicate with the oil storage portion, so the capacity of the check valve itself can be small and high responsiveness can be obtained. The present invention has an excellent effect.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of the device of the present invention, and FIG. 2 is II-II of FIG.
It is a cross-sectional view by a line. 3 ... Vane pump, 5 ... Throttle hole, 30 ... Rotor, 30
a …… Vane, 31 …… Cam ring, 32,33 …… Side plate, 41 …… First suction check valve, 49 …… Second suction check valve, 40 …… Pump chamber

Claims (1)

[Scope of utility model registration request] 1. A cylindrical rotor, which is provided with a plurality of plate-shaped vanes each having a throttle hole penetrating to the front and back sides so as to be able to advance and retreat in the radial direction, and interlocks with the other of the front and rear wheels. And a casing formed by mounting side plates on both sides of a rotating cam ring having an uneven thickness ring, respectively, and a plurality of casings surrounded by an outer peripheral surface of the rotor, an inner peripheral surface of the cam ring and side surfaces of both side plates. The rotor is housed in a casing so as to form a pump chamber to form a vane pump, pressure oil is sent to the pump chamber, and the front and rear wheels are driven by the hydraulic pressure generated against the flow resistance of the throttle hole. In the four-wheel drive drive connection device for connecting the plurality of suction oil passages, the one side plate is provided with a plurality of suction oil passages that respectively communicate the plurality of pump chambers and the oil storage portion, and the other side plate is provided with the plurality of suction oil passages. A plurality of discharge oil passages that respectively communicate the pump chamber and the oil storage portion, and a plurality of communication oil passages that divide the discharge oil passage in the middle and communicate with the oil storage portion, and the plurality of suction oil passages are provided. A suction check valve that allows only an inflow from the oil reservoir to the pump chamber for each of the plurality of communication oil passages, and an outflow from the pump chamber to the oil reservoir for each of the plurality of discharge oil passages. A drive coupling device for four-wheel drive, which is provided with a discharge check valve that allows only the above.