JPS6237563A - Bearing and seal structure - Google Patents

Abstract

PURPOSE:To maintain a sufficient seal function, by inserting a cylindrical bearing member to allow a positional slip along each radius direction of a rotating body and a fixed shaft. CONSTITUTION:A cylindrical fixed shaft 30 to be locked to a machine frame 9 is being inserted into a cylinder part 6a of a motor frame 6, while a distributing ring 31 is oiltightly supported on a tip end of this shaft 30 via elastic packing 32, and this distributing ring 31 is slidingly contacted with a distributing panel 16 in an eccentric manner. Now, if the fixed shaft 30 gets bent to some extent, an inner diameter of a bearing member 51 is being set to the value making the flection allowable, so that flection in the fixed shaft 30 is in no case influenced on the bearing member 51. At this time, a uniform minute clearance 58 is maintained on an outer surface of the bearing member 51 and an inner surface of the cylinder part 6a, and furthermore an O-ring 56 is interposingly installed between the outer surface of the fixed shaft 30 and the inner surface of the bearing member 51.

Description

Detailed Description of the Invention (1) Industrial Application Field The present invention relates to a bearing and a seal structure between a rotating body having a liquid chamber and a fixed shaft that enters the liquid chamber and is surrounded by the rotating body. .

(2) Conventional technology Conventionally, such bearings and seal structures have been developed, for example, in
A hydraulic transmission for a vehicle is disclosed in Japanese Patent No. 3208. That is, this transmission forms a hydraulic closed circuit between a hydraulic pump and a hydraulic motor, and a distribution board is fixed within a rotatable motor frame to define an oil chamber as a liquid chamber. A distribution ring that slides into contact with the distribution panel is supported at the tip of the fixed shaft that protrudes into the oil chamber. The distribution board and distribution ring are
In this state of sliding contact, hydraulic fluid is transferred between the hydraulic pump and the hydraulic motor. Furthermore, a cylindrical bearing member is fitted between the fixed shaft and the motor frame to perform a bearing and a sealing function.

(3) Problems to be Solved by the Invention However, in the conventional bearing and seal structures described above, when the fixed shaft is deflected, excessive force is applied to the bearing member, causing distortion, resulting in insufficient sealing function. There are some things you don't get.

The present invention has been made in view of the above circumstances, and provides a bearing that satisfies both bearing and sealing functions.
The purpose is to provide a sealing structure.

B0 Structure of the Invention (1) Means for Solving the Problems According to the present invention, there is a radial groove between the rotating body and the fixed shaft in order to allow for positional deviation in the radial direction between the rotating body and the fixed shaft. A cylindrical bearing member is inserted so as to be able to float therein, and either one of the rotating body and the fixed shaft is provided with a sealing member that constantly contacts the bearing member over its entire circumference.

(2) Action When the rotating body and the fixed shaft are misaligned in the radial direction, a liquid film maintains an even gap between the other of the rotating body or the fixed shaft and the bearing member. The sealing performance is maintained sufficiently.

(3) Examples Hereinafter, examples in which the present invention is applied to a vehicle hydraulic transmission will be explained with reference to the drawings.
In FIG. 1 showing an embodiment, this hydraulic transmission for a vehicle includes a swash plate type hydraulic pump 1 and a swash plate type hydraulic motor 2 that are connected to each other to form a hydraulic closed circuit. The driving force from the engine is input to the drive shaft 4 of the hydraulic pump 1 through the sprocket 3, and the hydraulic pressure discharged from the hydraulic pump 1 moves the hydraulic motor 2 by one force, thereby increasing the output provided to the hydraulic motor 2. The signal is transmitted to gear 5.

In the hydraulic motor 2, the motor frame 6 as a rotating body is
It is rotatably supported by a machine frame 9 by a bearing 7.8, and the output gear 5 is spline-coupled to a cylindrical portion 6a provided on the motor frame 6. Also hydraulic pump 1
The pump frame 10 is spline-coupled to the drive shaft 4, and the pump frame 10 and the drive shaft 4 are rotatably supported on the motor frame 6 with the same axis.

A plurality of pistons 11 are arranged in the pump frame 10 at equal intervals in the circumferential direction around the drive shaft 4 and are movable in a direction parallel to the axis of the drive shaft 4. The spherical heads 12 provided at the tips of the two abut against the inclined plates 13, respectively. Furthermore, this inclined plate 13 is rotatably arranged within the motor frame 6 via roller bearings 14,15. Further, on the opposite side of the pump frame 10 from the inclined plate 13, a distribution plate 16 is fixed in the motor frame 6, and the pump frame 10 is elastically attached to a spherical surface 17 provided on the distribution plate 16 by a spring 18. and liquid-tight sliding contact.

A plurality of pistons 19 are arranged in the motor frame 6 of the hydraulic motor 2 so as to surround each of the pistons 11 so as to be movable in a direction parallel to the axis of the drive shaft 4. The spherical protrusion 20 provided on the inclined plate 2
1. This inclined plate 21 is rotatably supported by roller bearings 23 and 24 within an inclined support frame 22, and the inclined support frame 22 has support shafts protruding from both sides in a direction perpendicular to the axis of the drive shaft 4. 25, it is pivotally supported on the machine frame 9.

The wall of the pump frame 10 that slides on the spherical surface 17 of the distribution board 16 is provided with oil holes 27 that individually communicate with the hydraulic chambers 26 defined between each piston 11 and the pump frame 10. The spherical surface 17 is provided with an arcuate discharge hole 28 and an arcuate suction hole 29 which communicate with the oil holes 27 in sequence. This discharge hole 28 is connected to the side of each piston 11 that ascends the slope of the inclined plate 13, that is, the piston 11 that is in a contracted state.
The suction hole 29 communicates with the oil hole 27 of the piston 11 on the side going down the slope of the inclined plate 13, that is, in the extended operating state.

Referring also to FIG. 2, a cylindrical fixed shaft 30 fixed to the machine frame 9 is inserted into the cylindrical portion 6a of the motor frame 6, and a distribution ring is attached to the tip of the fixed shaft 30. 31 is supported in an oil-tight manner via an elastic packing 32, and this distribution ring 31 is brought into sliding contact with the distribution plate 16 eccentrically. This results in
An inner chamber 33 and an outer chamber 34 as a liquid chamber are formed inside and outside of the distribution ring 31, which are isolated from each other.

On the other hand, in the hydraulic motor 2, oil holes 36 are drilled in the motor frame 6 and communicate with the hydraulic chambers 35 defined between each piston 19 and the motor frame 6. A plurality of oil passages 3 opened on the side of the distribution board 16
7 individually.

In the distribution panel 16, the discharge hole 28 is formed to communicate with the inner chamber 33, and the suction hole 29 is formed so as to communicate with the outer chamber 34. communicates with the inner chamber 33 when in the contracted operating state;
The corresponding piston 11 is configured to communicate with the outer chamber 34 when it is in the extended operating state.

Therefore, in the hydraulic pump 1, when the piston 11 is in the contracted state, the hydraulic pressure discharged from the hydraulic chamber 26 is supplied to the hydraulic chamber 35 of the corresponding piston 19 in the hydraulic motor 2. Further, when the piston 11 in the hydraulic pump 1 is in an extended state, the hydraulic chamber 26 of the piston 11 communicates with the outer chamber 34, and the hydraulic chamber 35 of the corresponding piston 19 in the hydraulic motor 2 also communicates with the outer chamber 34.

In this way, hydraulic oil is exchanged between the hydraulic pump 1 and the hydraulic motor 2, and the motor frame 6 of the hydraulic motor 2
It rotates according to the inclination angle of the inclined plate 21.

In order to control the inclination angle of this inclined plate 21, the inclined plate 2
A servo cylinder 38 is connected to one end of the inclined support frame 22 that supports the servo cylinder 1 .

Referring again to FIG. 2, the fixed shaft 30 protrudes into the outer chamber 34, and in order to prevent hydraulic oil from leaking from the outer chamber 34 and to support the fixed shaft 30 concentrically on the cylindrical portion 6a, the cylindrical portion is inserted into the outer chamber 34. A cylindrical bearing member 51 is inserted between 6a and the fixed shaft 30.

Referring also to FIG. 3A, the bearing member 51 is connected to the fixed shaft 3.
It has an inner diameter that allows for a deflection of 0, and the fixed shaft 3
It is connected to the outer surface of the fixed shaft 30 by a spline 52 having zero radial play. In order to restrict the axial movement of the bearing member 51, a restriction collar 53 facing one end of the bearing member 51 protrudes over the entire circumference of the fixed shaft 30, and a circlip facing the other end of the bearing member 51. 5
4 is fitted onto the fixed shaft 30.

The spline 52 is not provided between the bearing member 51 and the fixing member 30 in a portion closer to the regulating collar 53, and a fitting groove 55 is provided on the outer surface of the fixed shaft 30 over the entire circumference in this portion. An O-ring 56 and a backup ring 57 are fitted into the fitting groove 55 as sealing members that come into contact with the inner surface of the bearing member 51 .

A small annular gap 58 is formed between the outer surface of the bearing member 51 and the inner surface of the cylindrical portion 6a.

Inside the fixed shaft 51, communication between the inner chamber 33 and the outer chamber 34,
Clutch valve 59, which controls disconnection and connection between drive shaft 4 and motor frame 6, is rotatably inserted.

Next, to explain the operation of this embodiment, the driving force input from the engine to the drive shaft 4 is changed in speed according to the angle of the inclined plate 21, and is output from the output gear 5 provided on the motor frame 6. In this vehicle hydraulic transmission, the fixed shaft 30 may be bent.

In FIG. 3B, even if the fixed shaft 30 is bent by δ, the inner diameter of the bearing member 51 is set to a value that can tolerate the bending, and the bending of the fixed shaft 30 will not affect the bearing member 51. . At this time, the outer surface of the bearing member 51 and the cylindrical portion 6
A uniform minute gap 58 is maintained over the entire circumference between the fixed shaft 30 and the inner surface of the fixed shaft 30 by the oil film pressure of the hydraulic oil.
An O-ring 56 is interposed between the outer surface of the bearing member 51 and the inner surface of the bearing member 51.

Therefore, the hydraulic oil in the outer chamber 34 can be prevented from leaking to the outside, and a stable sealing function can be ensured.

In the above implementation, the bearing member 51 was coupled to the fixed shaft 30 by the spline 52 in order to prevent the rotation of the bearing member 5 in order to prevent the O-ring 56 from being damaged, but the second embodiment of the present invention As shown in Figure 4, the O ring 56
Instead, when using a seal ring 60 that is not likely to be damaged even if the bearing member 51 rotates, the spline 5
2 is unnecessary.

FIG. 5 shows a third embodiment of the present invention, in which a bearing member 51 is connected to the inner surface of a cylindrical portion 6a by a spline 61, and a regulating step 62 and a circlip 63 provided on the inner surface of the cylindrical portion 6a. axial movement is restricted by In addition, a circle ring 64 and a backup ring 65 are fitted into the inner surface of the cylindrical portion 6a, which abut the outer surface of the bearing member 51 over the entire circumference. Moreover, the spline 61 is connected to the bearing member 5.
The fixed shaft 30 is formed to have backlash in the radial direction so as to allow floating of the fixed shaft 30 .

According to this third embodiment, when the fixed shaft 30 is bent,
The bearing member 51 floats to form a uniform minute gap 66 over the entire circumference with the outer surface of the fixed shaft 30 due to the oil film pressure of the hydraulic oil, and performs a sufficient sealing function as in each of the above embodiments. be able to.

Although each of the above embodiments has been described in relation to the deflection of the fixed shaft 30, even when the cylindrical portion 6a of the motor frame 6 is deflected, the bearing member 51 floats and the sealing performance is maintained.

C1 Effects of the Invention As described above, according to the present invention, a cylindrical shape is provided between the rotating body and the fixed shaft to allow floating in the radial direction, in order to allow positional deviation of the rotating body and the fixed shaft in the radial direction. The bearing member is inserted, and either the rotary body or the fixed shaft is provided with a sealing member that constantly contacts the bearing member over the entire circumference, so even if the rotary body and the fixed shaft are misaligned, the bearing will remain intact. By floating the member, a uniform minute gap can be maintained between the bearing member and the other of the rotating body or the fixed shaft by liquid film pressure, and a sufficient sealing function can be maintained.

[Brief explanation of drawings]

1 to 3B show a first embodiment of the present invention, in which FIG. 1 is a longitudinal sectional side view of a hydraulic transmission for a vehicle, and FIG. 2 is an enlarged longitudinal sectional side view of the ■ part in FIG. , Figures 3A and 3B
The figure is a cross-sectional view taken along the line ■-■ of FIG. 2, FIG. 3A is a cross-sectional view in normal condition, FIG. 38 is a cross-sectional view when the fixed shaft is bent, and FIG. 4 is a second embodiment of the present invention. FIG. 5 is a longitudinal side view corresponding to FIG. 2 of the example, and FIG. 5 is a longitudinal side view corresponding to FIG. 2 of the third embodiment of the present invention. 6... Motor frame as a rotating body, 30... Fixed shaft,
34... Outer chamber as a liquid chamber, 51... Bearing member, 5
6゜64...0 ring as a seal member, 60...
・Seal ring as a sealing member Fig. 4 Fig. 5

Claims (1)

[Claims] In a bearing or seal structure between a rotating body having a liquid chamber and a fixed shaft that protrudes into the liquid chamber and is surrounded by the rotating body, there is a gap between the rotating body and the fixed shaft in the radial direction of the rotating body and the fixed shaft. A cylindrical bearing member is inserted so as to be able to float in the radial direction in order to allow for positional displacement along the axis, and a sealing member is provided on either the rotary body or the fixed shaft to constantly contact the bearing member over the entire circumference. Bearing and seal structure characterized by being provided.