JPS60231029A - Driving link device for four-wheel drive - Google Patents

Abstract

PURPOSE:To improve closing characteristics of check valves in a driving link device for four-wheel drive, by letting a center line of a large-diameter cylindrical hole, small-diameter cylindrical hole and conical surface of a check valve mechanism in a hydraulic link mechanism intersect a rotative center line of rotating shafts. CONSTITUTION:In a driving link device 13 for four-wheel drive comprising a hydraulic pump VP and a hydraulic circuit 21, check valves 28, 29, 29', 31 and 32 are provided between a first oil passage 26 and a second oil passage 27. A check valve mechanism CM is designed in such that a center line C1 of a large- diameter cylindrical hole 42, small-diameter cylindrical hole 43 and conical surface 44 intersects a rotative center line CL of a first rotating shaft 11 and a second rotating shaft 14 at the extension on the large-diameter cylindrical hole 42 side. With this arrangement, it is possible to quickly shift an open condition of the check valve mechanism to a closed condition thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a drive coupling device for driving front wheels and rear wheels with the same engine.

[Conventional technology]

Four-wheel drive (4-wheel drive) in which the front and rear wheels are driven by the same engine.
In a 4WD (4WD) car, there is a slight difference in the effective radius of the front and rear tires, and the difference in the rolling path of the wheels when cornering causes the tires to slip, causing unreasonable force to act on the drive system. It is necessary to provide means to prevent this.

For this reason, conventionally, in full-time four-wheel drive vehicles, even if there is a difference in rotational speed between the first rotating shaft that transmits driving force to the front wheels and the second rotating shaft that transmits driving force to the rear wheels, the drive A differential device called a center differential is used to transmit power, and it is disadvantageous compared to part-time 4-wheel drive vehicles in terms of weight, size, and cost, and because differential rotation is possible, 4-wheel drive vehicles are used. In some cases, four-wheel drive cannot be achieved when a drive is required, and the device becomes even more complex, such as requiring a differential locking mechanism.

On the other hand, many part-time 4-wheel drive vehicles do not have a center derailleur 7 installed, and if there is a problem caused by the 4-wheel drive such as tight corner braking caused by 1) corner braking, The vehicle is configured to have two-wheel drive when operated by a person, and has the disadvantage that driving operations are complicated.

Therefore, a four-wheel drive drive coupling device may be considered that includes a hydraulic coupling mechanism that can mutually transmit driving force between the first rotation shaft and the second rotation shaft.

[Problem that the invention seeks to solve]

However, when a vane pump is used as a differential pump in such a hydraulic coupling mechanism, the vanes of the vane pump are fitted to the rotor so that they can be protruded by the centrifugal force generated by the rotation of the rotor, and the rotor may stop. In the state,
Since the vanes on the upper part of the rotor do not make sufficient sliding contact with the inner circumferential surface of the casing, such a hydraulic coupling mechanism has the problem that sufficient driving force cannot be transmitted when the vehicle starts or rotates at low speed.

If a check valve mechanism a is arranged in the hydraulic circuit of this differential pump type coupling mechanism so that its cylindrical portion 1) is parallel to the rotation axis CL, as shown in FIG. Since the formed hydraulic circuit also rotates as the rotating shaft rotates, centrifugal force F acts on the spherical ball valve body, and the check valve becomes open.

Since the check valve in the open state is in an open state due to the centrifugal force F, there is a problem that the check valve cannot be immediately closed when switching to open/close.

In particular, when the differential pump type coupling mechanism is rotating at high speed, that is, at high vehicle speeds, the centrifugal force F becomes larger, making it even more difficult to close.

The present invention aims to solve these problems, and provides a drive connection for four-wheel drive that can improve the closing performance of a check valve mechanism in a hydraulic circuit of a differential pump type connection mechanism. The purpose is to provide equipment.

[Means for solving problems]

Therefore, the four-wheel drive drive coupling device of the present invention includes a first rotating shaft that transmits the driving force to the front wheels of the vehicle, a second rotating shaft that transmits the driving force to the rear wheels, and the first rotating shaft that transmits the driving force to the rear wheels. axis of rotation and the second
A hydraulic coupling mechanism is provided between the rotary shaft of the hydraulic coupling mechanism and the rotating shaft of the hydraulic coupling mechanism to mutually transmit driving force, and the hydraulic coupling mechanism is configured as a force pump type coupling mechanism, and the hydraulic circuit of the coupling mechanism is configured as a force pump type coupling mechanism. A check valve mechanism is provided, and the check valve mechanism has a large diameter cylindrical hole, a small diameter cylindrical hole, a conical surface serving as a valve seat connecting these large diameter cylindrical holes and the small diameter cylindrical hole, and a specific gravity of the hydraulic oil. a ball valve body having a larger specific gravity, and the center lines of the large diameter cylindrical hole, the small diameter cylindrical hole, and the conical surface are aligned with the first and second rotation axes on the extension of the large diameter cylindrical hole side. It is characterized by intersecting the center line of rotation.

[Effect]

With the above configuration, the centrifugal force generated by the rotation of the @1 and second rotating shafts acts as a force that closes the check valve mechanism.

〔Example〕

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.
1 to 5 show a four-wheel drive drive coupling device as an embodiment of the present invention. FIG. 1 is a cross-sectional view of the main parts thereof, FIG. 3 is a cross-sectional view of the present device, FIG. 4 is a vertical cross-sectional view of the device, and FIG. 5 is a schematic diagram illustrating its operation.

As shown in Fig. 2, a transmission 2 is attached to an engine 1 placed horizontally.
are connected to each other, and a drive gear 4 attached to its output shaft 3
Driving force is taken out from the idler gear 5 and transmitted to an intermediate transmission shaft 8 equipped with gears 6 and 7 at both ends.

Then, the driving force is transmitted from one gear 7 of this intermediate transmission shaft 8 to the differential device 10 for the front wheels 9 to drive the front wheels 9, while the driving force transmitted to the front wheels 9 is directly transmitted to the first rotation. A drive coupling device main body 1 for four-wheel drive is transmitted to the shaft 11 via a gear 12, and further serves as a differential pump type coupling mechanism.
3.

The driving force via this four-wheel drive drive coupling device main body 13 is transmitted to the second rotating shaft 14,
The driving force is transmitted to the differential device 17 for the rear wheels 16 via a bevel gear mechanism 15° 15' that changes the direction of rotation.
Drives the rear wheels 16.

As shown in FIGS. 3 and 4, this four-wheel drive drive coupling device main body 13 is composed of a vane pump vP as a hydraulic pump (hydraulic coupling mechanism) and a hydraulic circuit 21 attached thereto). The rotor 19 of the vane pump vP is the front wheel 9
The cam ring part 20a and the plate 20c that constitute the casing 20 are connected to the second rotating shaft 14 that transmits the driving force to the rear wheel 16. There is.

The vane pump VP as a hydraulic pump has a large number of holes 19b (eight in this case) shaped like T& at equal intervals in the circumferential direction on the outer circumferential surface 19a of the rotor 19. A vane 18 that can come into sliding contact with the inner circumferential surface 2()d of the cam ring portion 20a is fitted into each of the vanes 18.

In addition, the vane pump VP discharges an amount of oil proportional to its rotation speed, and the vane pump VP discharges an amount of oil proportional to its rotation speed.
When a relative rotation occurs between the first rotating shaft 11 and the second rotating shaft 14, the first rotating shaft 11 and the second rotating shaft 14 function as a hydraulic pump and generate hydraulic pressure.

Discharge port of vane pump ■P (suction and discharge ports 22 to 25 at the tip of the relative rotational direction of the vane 18 with respect to the casing 20)
(equivalent to this), the rotor 19 and the cam ring portion 20a become like a rigid body and are rotated together by the static pressure via the oil.

For this reason, two pump chambers 36 and 37 are formed at diagonal positions between the cam ring part 2(')a and the rotor 19, and when located on the base end side in the rotational direction, it becomes a suction port and on the distal end side. Four suction/discharge ports 22 located at
25 are formed at almost diagonal positions, and the diagonally located suction and discharge ports 22.24 and 23.25, which have the same function, keep oil on the stationary side even when the cam ring part 20a is rotating. The first oil passage 2
6 and a second oil passage 27.

Additionally, an oil reservoir 30 is connected between the first oil passage 26 and the second oil passage 27 via check valves 28, 29, and 29', respectively.
are in communication with each other, allowing only flow from the oil N30 to each oil passage 26+27, and allowing only outflow between the first oil passage 26 and the second oil passage 27. Two opposing check valves 31. Both oil passages 26 and 27 are communicated via a check valve 32, and an intermediate portion between the two check valves 31 and 32 is connected to an oil passage 40.
It communicates with the relief valve 33 via.

A communication passage 35 is provided between the oil reservoir 30 and the check valve 29' and the two check valves 28 and 29 through the intermediate portion of the relief valve 33 on the spring 34 side.

The check valves 28, 29, 31, 32 are configured as a check valve mechanism CM, and as shown in FIG. A side large-diameter cylindrical hole 42, an outflow side small-diameter cylindrical hole 43, and these large-diameter cylindrical holes 42 and small-diameter cylindrical holes 4.
3, and a large diameter cylindrical hole 42. Small diameter cylindrical hole 43 and circular surface 44
The center line C1 is arranged to be the rotation center line CL of the first rotating shaft 11 and the second rotating shaft 14 on the extension of the large diameter cylindrical hole 42i1.

The intersection angle a between the center line C1 and the rotation center line CL is such that the difference (α-γ) from the angle γ of (1/2) of the cone angle is 20 degrees or less. Mainly, a communication oil passage 38 that communicates the first oil passage 26 connected to the suction discharge port 24 and the oil passage 27 connected to the suction discharge port 23.
An orifice 3 is provided in this communication oil passage 38.
9 is interposed. This orifice 39 is configured, for example, as a centrifugal orifice mechanism, and the rotation shaft 11
．． 14, the orifice diameter becomes smaller during high rotations and becomes larger during low rotations.

With such a hydraulic circuit 21, the discharge pressure always acts on the valve body of the relief valve 33, regardless of the relative rotation direction between the rotor 19 and the cam ring portion 20a, and the oil reservoir 30 communicates with the suction port. become.

In addition, the reference numeral 45 in FIG. 4 is a bear link, 46 is a case (1 lance transmission cable, etc.), 47 is a suction port, and 48 is a
indicate each bolt.

Since the four-wheel drive drive coupling device of the present invention is configured as described above, when the vehicle is normally traveling straight, the effective radius of the tires of the front wheels 9 and rear wheels 16 is the same, and the slip rotation speed of the tires is The first rotating shaft 11 and the second rotating shaft 14 are connected to the four-wheel drive drive coupling device main body 13.
There is no difference in rotational speed between the two.

Therefore, the vane pump VP does not generate oil pressure,
No driving force is transmitted to the rear wheels 16, and only the front wheels 9 drive the front wheels.

However, in a state where the front wheels 9 normally slip within about 1% even without a large slip 7, such as when the vehicle is accelerating straight ahead, the difference in rotational speed due to this is caused between the first rotating shaft 11 and the second rotating shaft 11.
When the rotor 1
9 and the cam ring part 20a rotate together, and a driving force corresponding to this oil pressure and the pressure receiving area of the vane is applied to the rear wheel 16.
The transmission is transmitted to four-wheel drive mode.

In this case, the oil flow in the vane pump VP is caused by the relative rotation of the rotor 19 (see symbol A in FIG. While oil is sucked in from the oil reservoir 30, the suction/discharge port 23.25 becomes a discharge port, and at the same time, the check valve 29.31 is closed and the check valve 29.31 is closed. Valve 32° Oil passage 4
Oil is led to the relief valve 33 via the valve 0.

In addition, in FIG. 3, solid line arrows indicate the flow of discharged oil, and broken line arrows indicate the flow of suction oil.

Then, as the rotational speed of the first rotating shaft 11 and the second rotating shaft 14 increases and the centrifugal force that the vane 18 receives increases, the tip portion (outer diameter end portion) of the vane 18 is moved toward the cam ring portion. 20a, and the vanes 18 touch the inner peripheral surface 20d1.20a of the cam ring portion 20a. The state of sliding in close contact is maintained.

Note that a vane biasing mechanism that presses the base end (inner diameter end) of the vane 18 may be provided as appropriate. In this case, when the vehicle is stopped, the first rotation shaft 11 and the second rotation shaft 14 Even if they do not rotate, the vane 18 is always urged in the projecting direction, so the connection function of the vane pump ■P is maintained at a sufficiently high level.

Next, the rotational speed of the front wheels 9 compared to the rotational speed of the rear wheels 16.
If the torque becomes very large, for example, if the front wheels slip on a snowy road or the rear wheels tend to lock up during sudden acceleration or braking, the The difference in rotational speed between the first rotating shaft 11 and the second rotating shaft 14 becomes very large.

As a result, in the vane pump ■P, the oil flow shown in Fig. 3 occurs and a large hydraulic pressure is generated, but when a predetermined value is exceeded, the relief valve 33 opens against the spring 34 and the discharge pressure remains almost constant. A four-wheel drive state is established in which a constant driving force corresponding to a constant discharge pressure is transmitted to the rear wheels 16.

Then, as the rotational speed of the front wheel 9 decreases, the rear wheel 1
6's rotational speed increases, reducing the rotational speed difference (
Same function as non-slip differential).

In this way, when the front wheels 9 are in a slip state, the drive torque to the rear wheels 16 is increased, making it impossible to drive, and when the rear wheels 16 are a little locked, the brake torque of the front wheels 9 is increased. to prevent the rear wheels 16 from locking.

On the other hand, when the rotational speed of the rear wheels 16 becomes very large compared to the rotational speed of the front wheels 9, for example, when the front wheels 9 are slightly locked in the braking state, the first A very large rotational speed difference occurs between the rotating shaft 11 and the second rotating shaft 14 in the opposite direction to that described above.

As a result, in the vane pump vP, an oil flow occurs in the opposite direction to the oil flow shown in FIG.
serves as a suction port, and oil is sucked in from the oil reservoir 30 via the check valves 29, 29', while the suction and discharge ports 22.
24 becomes the discharge port and passes through the first oil passage 26 to the check valve 28
, 3.2 and close the check valve 31 and the relief valve 33.
However, this oil pressure is also kept constant by the relief valve 33, and a constant driving force is applied to the rear wheels 16.
The transmission is transmitted to four-wheel drive mode.

Then, the brake torque to the rear wheels 16 is increased and the brake torque to the front wheels 9 is increased.
prevent locking.

That is, in the check valve mechanism CM, as shown in FIG. When the check valve mechanism CN4 is applied to the right in FIG. 5 from the perpendicular line ρ of the radial conical surface 44, the check valve mechanism CN4 is closed, and when it is applied to the left, the check valve mechanism CM is opened.

Here, since the resultant force F is applied to the right side in FIG. 5 from the perpendicular line ρ, the check valve mechanism CM changes from the open (Op) state to the closed (C
The transition to the 1) state is performed by the check valves 28 and 32, but when the hydraulic oil supplied to the large diameter cylindrical hole 42 stops, the spherical ball valve body 41 has a higher specific gravity than the hydraulic oil, so the spherical ball valve body 41 The ball valve body 41 is immediately pressed against the conical surface 44 by the centrifugal force F, and the check valve 28, 32 is quickly closed.

As a result, the oil pressure in the first oil passage 26 is reduced to the suction and discharge port 22.
．． The pressure immediately increases to the discharge pressure from 24.

Note that since the spherical ball valve body 41 is made of a material with a specific gravity greater than the specific gravity of the hydraulic oil, it sinks in the direction of gravity of the large diameter cylindrical hole 42 when the rotation of the vane pump VP is stopped.

Also, during normal cornering, the rotational speed of the front wheels 9 is slightly greater than the rotational speed of the rear wheels 16, causing the front wheels 9 to have a play 4.
) and a four-wheel drive state in which driving torque is applied to the rear wheels 16 and cornering is performed.

In this way, by controlling the discharge pressure in the 4-wheel drive drive coupling device main body 13 using the relief valve 33 so that it does not exceed a certain value, it is possible to control the discharge pressure in the 4-wheel drive drive coupling device main body 13 so that it does not exceed a certain value. Previously, the driver's operation was required, but now the system automatically switches between 4-wheel drive and 2-wheel drive, and the 4-wheel drive system uses driving force according to the difference in rotational speed between the front wheels 9 and rear wheels 16. A driving state is obtained.

In addition, compared to the center differential that was always installed in conventional full-time 4-wheel drive vehicles, this device is smaller and more compact, and also reduces weight.
It also reduces costs.

By the way, when the vehicle is running at low speed, the orifice diameter of the orifice 39 increases and the amount of oil flowing through the communication oil passage 38 increases, so when the vehicle makes a sharp turn, the discharge pressure decreases and the driving force transmission efficiency decreases. .

That is, when the rotational speed difference between the front wheels 9 and the rear wheels 16 is smaller than the permissible rotational speed difference between the front and rear wheels, it is possible to reliably avoid the braking phenomenon during sharp turns.

On the other hand, when the vehicle is running at high speed, the orifice diameter of the orifice 39 becomes smaller, and the amount of oil flowing through the communication oil passage 38 decreases, so that the discharge pressure becomes higher and the driving force transmission efficiency increases.

That is, if the rotational speed difference between the front wheels 9 and the rear wheels 16 is larger than the allowable rotational speed difference between the front and rear wheels, the front wheels 9
A difference in rotational speed between the rear wheels 16 and 16 is not allowed, resulting in a four-wheel drive state, improving straight-line stability.

In this way, when turning at high speed, the turning radius is large, so
Braking phenomena are minimal, and four-wheel drive ensures stable handling.

Furthermore, in addition to a balanced vane pump with four suction and discharge ports as the hydraulic pump for the four-wheel drive drive coupling device main body 13, depending on the amount of driving force transmitted, an unbalanced vane pump with two suction and discharge ports may be used. It's okay.

According to the embodiments of the present invention, the following effects and advantages can be obtained.

(1) Since differential rotation between the Ti wheels and the rear wheels is allowed, it is possible to eliminate problems such as tight corner braking of part-time four-wheel drive vehicles and the complexity of driving.

(2) Due to the opening between the first rotating shaft and the second rotating shaft, force is transmitted from the faster rotating shaft to the slower rotating shaft.
This prevents one of the front wheels or the rear wheels from over-rotating, reliably preventing wheelspin, and contributing to vehicle safety.

(3) It can be made smaller and lighter than the center differential conventionally equipped on full-time four-wheel drive vehicles, and can also contribute to lower costs.

〔Effect of the invention〕

As detailed above, according to the four-wheel drive drive coupling device of the present invention, the first rotating shaft transmits the driving force to the front wheels of the vehicle, and the second rotating shaft transmits the driving force to the rear wheels. and a hydraulic coupling mechanism that is interposed between the first rotating shaft and the second rotating shaft and capable of mutually transmitting driving force, and the hydraulic coupling mechanism is a differential pump type coupling. A check valve mechanism is provided in the hydraulic circuit of the coupling mechanism, and the check valve mechanism has a large-diameter cylindrical hole, a small-diameter cylindrical hole, and a valve connecting these large-diameter cylindrical holes and the small-diameter cylindrical hole. It is composed of a conical surface as a seat and a ball valve body having a specific gravity greater than the specific gravity of the hydraulic oil, and the center line of the large diameter cylindrical hole, small diameter cylindrical hole and conical surface is on the side of the large diameter cylindrical hole. With a simple configuration in which the extension intersects with the rotation center lines of the first and second rotation shafts, there is an advantage that the check valve mechanism can quickly shift from the open state to the closed state. Even when the relative rotation direction of the rotation shaft and the second rotation shaft is reversed, the discharge pressure from the differential pump can be immediately increased.

[Brief explanation of the drawing]

1 to 5 show a four-wheel drive drive coupling device as an embodiment of the present invention. FIG. 1 is a cross-sectional view of the main parts thereof, FIG. 3 is a cross-sectional view of this device, FIG. 4 is a vertical sectional view of this device, FIG. 5 is a schematic diagram explaining its operation, and FIG. 6 is a schematic diagram showing the operation of a conventional check valve mechanism. It is. 1. Horizontal engine, 2. Transmission, 3. Output shaft, 4
... Drive gear, 5.. Idle gear, 6.7.. Gear, 8.. Intermediate transmission shaft, 9.. Front wheel, 10.. Differential device, 11.. First rotating shaft, 12.. Gear , 13... 4-wheel drive drive coupling device main body as a differential pump type coupling mechanism, 14... second rotating shaft, 15.15'... bevel gear mechanism, 16... rear wheel, 17... differential Dynamic device, 18...Vane, 19...Rotor, 19a...Outer peripheral surface, 19b...
Hole, 20...Casing, 20a...Cam ring part,
20b...Plate, 20c...Plate, 20d...
Inner peripheral surface, 21... Hydraulic circuit, 22-25... Suction/discharge port, 26... First oil passage, 27... Second oil passage, 28.29.
29'...Check valve, 30...Oil reservoir, 31.3
2.Check valve, 33.Relief valve, 34.Spring, 35.Communication path, 36.37.Pump chamber,
38... Communication oil passage, 39... Orifice, 4°... Oil passage, 41... Spherical ball valve body, 42... Large diameter cylindrical hole, 43
・・Small diameter cylindrical hole, 44・・Conical surface as valve seat, 45・
・Bearing, 46...Case, 47...Suction port, 48
・・Bolt, C1・・Center line, cL・・Rotation center line, C
M...Check valve mechanism, VP...Vane pump. Agent Patent Attorney Yoshihiko Iinuma Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 0 201) Fig. 5 Fig. 6

Claims (1)

[Claims] A first rotating shaft that transmits driving force to the front wheels of the vehicle, a second rotating shaft that transmits driving force to the rear wheels, and an interposed device between the first rotating shaft and the second rotating shaft. and a hydraulic coupling mechanism capable of transmitting driving force to each other, the hydraulic coupling mechanism is configured as a force pump type coupling mechanism, and a check valve mechanism is provided in the hydraulic circuit of the coupling mechanism, The check valve mechanism includes a large-diameter cylindrical hole, a small-diameter cylindrical hole, a conical surface as a valve seat that connects these large-diameter cylindrical holes and the small-diameter cylindrical hole, and a ball valve body having a specific gravity greater than the specific gravity of the hydraulic fluid. Kara structure 1. - characterized in that the center lines of the large diameter cylindrical hole, the small diameter cylindrical hole, and the conical surface intersect with the rotation center lines of the first and second rotation shafts on the extension of the large diameter cylindrical hole side. A drive coupling device for four-wheel drive.