JP2567998Y2 - Driving force transmission device for four-wheel drive vehicles - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving force transmitting device for a four-wheel drive vehicle which transmits driving force between a pair of drive shafts for a four-wheel drive vehicle.

[0002]

2. Description of the Related Art In recent years, four-wheel drive vehicles have been rapidly spreading in recent years because they are not only excellent on rough roads, but also excellent on acceleration and running stability on general roads. In this four-wheel drive vehicle, in order to prevent the so-called tight corner braking phenomenon, etc., allow a difference in rotational speed between both front and rear wheel drive shafts or between left and right wheel drive shafts. A driving force transmission device that can perform the operation is interposed.

[0003] As the above-mentioned driving force transmission device, a casing which rotates in conjunction with one of the input and output shafts and has a plurality of concave portions on the inner peripheral surface, and is accommodated in the casing and rotates in conjunction with the other. And a columnar rotor forming a pump chamber between the outer peripheral surface and the recess of the casing, and a vane slidably inserted into a plurality of storage grooves formed on the peripheral surface of the rotor. There is a vane pump that transmits torque between input and output shafts through a hydraulic pressure generated according to a difference in rotation speed between a rotor and a casing.

In this driving force transmission device, a desired high pressure cannot be generated in the pump chamber unless each vane is securely sealed to the inner peripheral surface of the casing. Each vane is biased toward the inner peripheral surface side of the casing by a coil spring interposed between the bottom of the storage groove. However, with this coil spring alone, it was not possible to obtain a sufficient push-up force of the vane against the high pressure in the pump chamber, and the sealing by the vane was uncertain.

Therefore, an oil passage for guiding the pressure oil from the pump chamber to the bottom of the housing groove is provided in the inner portion (side plate) of the casing, and a check valve for allowing only the outflow of the pressure oil from the pump chamber to the oil passage. There has been a driving force transmission device in which the vane is pressed against the inner peripheral surface side of the casing by the pressure oil from the pump chamber. However, there is a disadvantage that the casing becomes thicker and the driving force transmission device becomes larger.

Therefore, in order to reduce the size, an opening is provided at a predetermined position between adjacent vanes on the peripheral surface of the rotor, and only the outflow of pressure oil from the pump chamber to the bottom of each storage groove is performed halfway. A drive oil having a so-called check valve built-in type rotor in which a discharge oil passage provided with a check valve that allows pressure is provided, and pressure oil in the pump chamber is introduced to the bottom of each storage groove via the discharge oil passage. A transmission device has been provided (see, for example, Japanese Patent Application Laid-Open No. 2-300524).

[0007]

However, in this driving force transmitting device, the number of discharge oil passages and check valves equal to the number of vanes is provided. Had the drawback of becoming expensive. Further, when assembling the vane pump, it takes time and effort to assemble the check valve having a large number of components, and there is a problem that the manufacturing cost is increased due to the large number of processing steps of the discharge oil passage and the high component cost. The present invention has been made in view of the above technical problem, and has as its object to provide a driving force transmission device for a four-wheel drive vehicle that can reduce manufacturing costs by reducing the number of processing steps, component costs, and assembly steps.

[0008]

In order to achieve the above object, a four-wheel drive vehicle driving force transmission device according to the present invention rotates in conjunction with one of input and output shafts and has an inner peripheral surface. A casing having a plurality of recesses, a cylindrical rotor housed inside the casing and rotating in conjunction with the other and forming a pump chamber between the outer peripheral surface and the recess of the casing; and a peripheral surface of the rotor. A vane slidably inserted in a plurality of storage grooves formed in the rotor, and an opening at a predetermined position on the peripheral surface of the rotor, and only the outflow of pressure oil from the pump chamber to the bottom of the storage groove in the middle thereof A four-wheeled vehicle having a vane pump having a plurality of discharge oil passages provided with a check valve that allows a torque, and transmitting torque between input and output shafts through a hydraulic pressure generated according to a rotational speed difference between a rotor and a casing. Driving force transmission for driving vehicles In the device, the number of pump chambers and the number of vanes are set so that the pressure characteristics of each pump chamber have a phase difference, and one of the discharge oil passages provided with the check valves has a high pressure with a phase difference. The number of the discharge oil passages is set to a predetermined number equal to or less than half of the number of vanes so as to communicate with the pump chamber, and each opening has a phase difference in the circumferential direction of the rotor. It is characterized by being arranged in a position.

[0009]

According to the driving force transmitting apparatus for a four-wheel drive vehicle having the above-described structure, each pump chamber has a high pressure with a phase difference, but a predetermined number of pump chambers are provided for the high-pressure pump chamber. Since any one of the discharge oil passages communicates, the pressure oil in the pump chamber can always be introduced to the bottom of each storage groove via the discharge oil passage. With this pressure oil, all the vanes can be pressed toward the inner peripheral surface side of the casing. Thereby, sealing by all vanes is ensured, and a predetermined pressure characteristic having a phase difference can be obtained in each pump chamber.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 2 is a longitudinal sectional view showing a driving force transmission device for a four-wheel drive vehicle as one embodiment of the present invention. Referring to FIG. 1, the driving force transmission device is provided between an input shaft 1 that rotates in conjunction with one of the front and rear wheels, and an output shaft 2 that rotates in conjunction with the other of the front and rear wheels. The vane pump 3 generates a hydraulic pressure according to the difference.

In the vane pump 3, a rotor 30 connected to an output shaft 2 as described later is coaxially rotatably housed in a casing 3a connected to an input shaft 1 as described later. It is provided in a differential gear device (not shown) that transmits the driving force of the engine to the left and right wheels. The casing 3a of the vane pump 3 includes a cam ring 31 having a short cylindrical shape, a pressure plate 32 and a side plate 33 having a hollow disc shape coaxially positioned on both sides of the cam ring 31. A bracket 36 having a boss portion 36a extending inward and closely attached to an end surface of the pressure plate 32, the pressure plate 32, and the cam ring 31;
The cam ring 31, the pressure plate 32, and the side plate 33 are integrally connected to each other by a plurality of bolts 37 (only one is shown) which respectively penetrates in the thickness direction and is screwed to the side plate 33. I have.
The input shaft 1 is spline-coupled to the boss portion 36 a of the bracket 36, whereby the casing 3 a is rotated in conjunction with the rotation of the input shaft 1.

On the other hand, the rotor 30 of the vane pump 3 has a short cylindrical shape having substantially the same length as the cam ring 31, and is housed inside the cam ring 31 and spline-coupled to the rotor shaft 4 serving as a rotating shaft. ing. The rotor shaft 4 is slidingly supported coaxially by the inside of the hollow portion of the pressure plate 32 and the hollow portion of the side plate 33 in a state of being fitted therein. Referring to FIG.
The rotor 30 is provided with a plurality of storage grooves 30b having a predetermined depth in the radial direction and equally arranged in the circumferential direction, and each of these grooves has a rectangular flat plate-like vane 34 (in this embodiment, 10 vanes 34). ) Are retractably stored. Each vane 3
4 is urged radially outward by a coil spring 35. Referring to FIG. 3, one end of coil spring 35 is inserted into spring receiving recess 34b on the base end side of vane 34, and the other end is fixed to the bottom of storage groove 30b by holding body 5. Have been. The holding body 5 has a support plate 50 having a pair of holding portions 50a for holding between both end surfaces 30a of the rotor 30, and a holding rod that stands upright at the center of the support plate 50 and has the other end of the spring fitted therein. 51. The dimension of the holding rod 51 in the axial direction is set so that the tip thereof always faces the inside of the spring receiving hole 34b irrespective of the advance / retreat stroke of the vane 34.

A plurality of modified crescent-shaped pump chambers 40 a surrounded by the inner peripheral surface of the cam ring 31, the outer peripheral surface of the rotor 30, the pressure plate 32 and the side plate 33 are provided at positions corresponding to the concave portions on the inner periphery of the cam ring 31. ~ 40
c (three in this embodiment) are formed on the inner peripheral surface of the cam ring 31 at equal circumferential intervals. An annular sealing member 61 seals between the outer periphery of the rotor shaft 4 and the inner periphery of the pressure plate 32 and between the outer periphery of the rotor shaft 4 and the side plate 33. Further, between the cam ring 31 and the pressure plate 32,
An O-ring 62 hermetically seals between the side plate 33 and the side plate 33. The boss portion 36a of the bracket 36 is fitted inside the left side portion of the hollow portion of the rotor shaft 4. The output shaft 2 is internally fitted to the right side of the hollow portion of the rotor shaft 4, and both are spline-coupled. Thereby, the rotor 3
0 will rotate in conjunction with the rotation of the output shaft 2,
Between the casing 3a of the vane pump 3 and the rotor 30,
That is, relative rotation corresponding to the difference in rotation speed between the front and rear wheels occurs, and hydraulic pressure is generated in the pump chamber as described later.

The pressure characteristics of the pump chambers 40a,..., 40c have a predetermined phase difference (see FIG. 4).
The number of pump chambers and the number of vanes are set to predetermined values (in the present embodiment, ten vanes 34 are provided for the three pump chambers 40a to 40c, and the numbers of both vanes are divisors to each other). Without such a relationship, it is possible to generate a pressure characteristic having the above-mentioned phase difference).

Referring to FIGS. 1 and 2, orifices 34 are provided in vanes 34 to allow oil to flow through both sides of the space formed by partitioning the pump chamber.
a is provided. In addition, the pressure plate 32
Inner end surface 32a and the inner end surface 33a of the side plate 33
Are formed with annular concave portions 32b and 33b which allow the holding portion 50a of the holding body 5 holding the coil spring 35 to enter.

The rotor 30 has a check valve which is opened on the outer peripheral surface of the rotor 30 between the mounting positions of the vanes 34 adjacent to each other by an opening 44a and which only allows outflow of pressurized oil from the pump chamber halfway. A predetermined number of discharge oil passages 6a to 6d provided with 46 are provided. Each discharge oil passage 6a,.
6d is a radial path 44 having a predetermined depth in the radial direction.
And an axial path 45 communicating with the bottom of each radial path 44 and passing through the rotor 30 in the axial direction and communicating with the annular recess 32b. The check valve 46 is fitted in the middle of the axial path 45. The number of the discharge oil passages 6a to 6d provided with the check valve 46 is as follows.
The predetermined number (four in this embodiment) is equal to or less than half (five in this embodiment) the number of vanes 34, and any one of these discharge oil passages 6a to 6d has a phase difference. The openings 44a are arranged with a phase difference in the circumferential direction of the rotor 30 so as to communicate with the pump chambers 40a,.

The operation of the vane pump 3 configured as described above will be described. When a difference in rotation speed occurs between the front and rear wheels, and the rotation speed between the input and output shafts 1 and 2 is different,
A relative rotation occurs between the rotor 30 and the casing 3a. When the relative rotation occurs in this way, as shown in FIG.
It rotates with the rotation of 0. Then, the volume of the sealed space A defined by the surface on the downstream side in the rotation direction of the vane 34 rotating in the pump chamber 40a, the concave surface of the cam ring 31 and the outer peripheral surface of the rotor 30 is reduced. Thereby, a high pressure is generated in the sealing space A. If you rotate further,
Opening 44a of discharge oil passage 6b in pump chamber 40b
Becomes high pressure, and then the pump chamber 40c
The pressure in the sealed space corresponding to the discharge oil passage 6c becomes high, and then the discharge oil passage 6d in the pump chamber 40a.
Becomes high pressure in the sealing space corresponding to
Pump chamber 4 in which the two discharge oil passages 6a to 6d become sequentially high pressure
It will correspond sequentially to the sealing space in 0a-40c. Then, with the relative rotation of the rotor 30 and the casing 3a, pressure oil is introduced into the bottom of each storage groove 30b through these discharge oil passages 6a to 6d, and all the vanes 34 are caused by this pressure oil. It is pressed against the inner peripheral surface of the cam ring 31. Thereby, all the vanes 34 are reliably sealed, and pressure characteristics having a predetermined phase difference can be obtained in each of the pump chambers 40a,..., 40c. The pressure acts as a piston pressure in each of the pump chambers 40a,..., 40c. As a torque transmission medium, torque is transmitted from the rotor 30 to the cam ring 31. A torque distribution is performed between the rear wheels.

Hydraulic oil flows from the high-pressure sealed space via the orifice 34a of the vane 34 into the sealed space on the upstream side in the rotational direction of the vane 34 with a predetermined flow resistance. The high pressure in the sealed space is mainly determined by the flow resistance. As described above, according to the present embodiment, the same number of discharge oil passages and check valves as the number of vanes in the related art is used, but the required minimum number of discharge oil passages 6a to 6d with check valves is provided. Either
By arranging the pump chamber to always communicate with the high-pressure pump chamber, it is possible to achieve a vane lifting function equivalent to that of the related art. Therefore, the discharge oil passages 6a to 6d
The number of processing steps for processing the material can be reduced. Further, since the number of check valves 46 can be reduced by half as compared with the related art, it is possible to reduce the cost of parts and the number of assembling steps, and to reduce the manufacturing cost in combination with the above-described reduction of the number of processing steps.

The present invention is not limited to the above-described embodiment. For example, the driving force transmission device for a four-wheel drive vehicle can be used for transmitting torque between a left front wheel and a right front wheel. Further, it can be used for transmitting torque between the left rear wheel and the right rear wheel. Furthermore, the number of pump chambers, the number of vanes, the number of discharge oil passages, and the arrangement positions of the openings can be arbitrarily set under the above-described conditions, and various other conditions are provided without changing the gist of the present invention. Design changes can be made.

[0020]

As described above, according to the driving force transmission device for a four-wheel drive vehicle of the present invention, the number of discharge oil passages with check valves, which is conventionally provided by the same number as the number of vanes, is reduced to less than half of the number of vanes. By reducing the number to a predetermined number, these discharge oil passages can fulfill the same vane lifting function as the conventional one. Therefore, the number of processing steps for the discharge oil passage can be reduced, and the number of check valves can be reduced to reduce the parts cost and the number of assembling steps.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a driving force transmission device for a four-wheel drive vehicle according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a driving force transmission device for a four-wheel drive vehicle.

FIG. 3 is an enlarged view showing a mounted state of a coil spring for urging the vane.

FIG. 4 is a diagram showing a rotation angle of a rotor and a pressure characteristic in each pump chamber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input shaft 2 Output shaft 3 Vane pump 3a Casing 6a-6d Discharge oil path 30 Rotor 30b Storage groove 34 Vane 40a-40c Pump room 44a Opening

Claims (1)

(57) [Scope of request for utility model registration] A casing which rotates in conjunction with one of the input / output shafts and has a plurality of recesses on an inner peripheral surface thereof; A cylindrical rotor forming a pump chamber between the concave portion of the rotor and a vane slidably inserted into a plurality of storage grooves formed on the peripheral surface of the rotor;
A vane pump having a plurality of discharge oil passages each having an opening at a predetermined position on the peripheral surface of the rotor and having a check valve arranged in the middle of the opening to allow only pressure oil to flow from the pump chamber to the bottom of the storage groove, In a driving force transmission device for a four-wheel drive vehicle that transmits torque between input and output shafts through a hydraulic pressure generated according to a rotation speed difference between a rotor and a casing, a phase difference is generated in a pressure characteristic of each pump chamber. The number of pump chambers and the number of vanes are set so as to have, so that any one of the discharge oil passages provided with the check valves communicates with the pump chamber that has a high pressure with a phase difference.
A four-wheel drive, wherein the number of the discharge oil passages is set to a predetermined number equal to or less than half of the number of vanes, and each opening is arranged with a phase difference in a circumferential direction of the rotor. Driving force transmission device for vehicles.