JPH08312648A - Main shaft slide bearing for hydraulic pump motor - Google Patents

Abstract

PURPOSE: To provide a main shaft slide bearing for a hydraulic pump motor to absorb and relax one-sided contact of a bearing bush even when a sideways high load is exerted on the rotary shaft of a hydraulic pump and the rotary shaft is deformed and prevent the occurrence of seizure and wear. CONSTITUTION: The main shaft slide bearing of a hydraulic pump motor is structured in such a manner that a plurality of slits 2d are formed in the rotary shaft of the hydraulic pump and a part of a bearing bush 2b on the one-sided contact side, and the back of a bush 2b or the equivalent part in the axial direction of the slit 2d on the bush press-in holder side is escaped, and the back of the bush 2b and the equivalent part in an axial direction of the slit 2d of a bush holder 2a are brought into no contact with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle slide bearing applied to a piston type hydraulic pump motor.

[0002]

2. Description of the Related Art FIG. 4 shows a longitudinal section of a conventional structure example of a swash plate type piston pump. In the figure, 1 is a rotation axis, 2A, 2B
Is a bearing for supporting the rotary shaft 1, 3 is a cylinder barrel, 4 is a valve plate, 5 is a swash plate, 6 is a piston, 7 is a shoe crimped to the spherical portion of the piston 6, 8 is a shoe retainer, and 9 is a ball retainer. Reference numeral 10 denotes a casing, 11 denotes a seal, and 12 denotes a spline.

The piston 6 is pressed against the swash plate 5 via the shoe 7 by the discharge pressure. As the reaction force, a force F is applied to the piston from the swash plate 5. The orthogonal component of the force with respect to the rotation axis 1 is applied to the rotation axis 1 via the spline 12. The resultant force F of the plurality of pistons 6 is applied as a lateral load to the rotating shaft. Moreover, the lateral load F increases in proportion to the discharge pressure.

Due to the lateral load F, the rotary shaft 1 is flexibly deformed, and the bearings 2A and 2B are partially biased. In order to prevent this one-sided contact, a rolling bearing such as a spherical roller bearing or a roller bearing that can absorb one-sided contact is used as a bearing in a hydraulic pump motor. However, when a normal metal slide bearing is used for the bearings 2A and 2B, there is a problem that seizure or abrasion damage is likely to occur due to one-sided contact.

In a water / glycol-based hydraulic fluid pump motor, a sliding bearing is used because the rolling bearing has a short life, but a resin bearing is used to prevent seizure due to one-sided contact. Resin bearings prevent excessive one-sided contact due to deformation and wear to prevent seizure damage, but have the drawback that they do not last long because of wear.

[0006]

In the piston type hydraulic pump motor, a large lateral load proportional to the discharge pressure acts on the rotary shaft from the swash plate 5 as described above, so that the bearings 2A and 2B are partially hit. To prevent this one-sided contact, a spherical roller bearing or roller bearing is used as a bearing in the hydraulic pump motor. However, when a normal metal slide bearing is used for the bearings 2A and 2B, there is a problem that seizure or abrasion damage is likely to occur due to one-sided contact.

Further, the water and glycol type hydraulic fluid pump motor has a resin bearing in order to prevent seizure due to one-sided contact, but the resin bearing has a drawback in that it has a long life due to much wear. ing.

An object of the present invention is to provide a hydraulic pump motor which is capable of preventing seizure and wear by absorbing and mitigating one side contact of the bearing bush even if a large lateral load is applied to the rotary shaft and the rotary shaft is deformed. The main purpose is to provide plain bearings.

[0009]

A main shaft slide bearing of a hydraulic pump motor according to the present invention is a rotary shaft slide bearing of a piston type hydraulic pump motor, wherein a plurality of bearing bushes on one side of the rotary shaft are provided. With the slit of the book, the bush back surface or the axially corresponding portion of the slit on the bush press-fit holder side is allowed to escape so that the bushing back surface and the axially corresponding portion of the slit of the bush holder do not come into contact with each other. .

[0010]

The bearing load F in the lateral direction is applied to the bush 2b from the rotating shaft 1. Further, the rotary shaft is flexibly deformed by the lateral load F, is inclined with respect to the bush, and is in one-side contact with the slide bearing. The bush has a plurality of axial slits 2d,
Since there is a gap between the bush back surface and the bush holder, it is possible to deform along the inclination of the rotating shaft 1,
One-sided contact between the rotating shaft 1 and the bush 2b can be prevented. A gap is formed between the back surface of the bush and the bush holder, and the deformation amount of the bush 2b is regulated by this gap amount, and it is possible to prevent the bush 2b from being damaged due to excessive bending deformation.

[0011]

EXAMPLES Examples of the present invention will be described below with reference to FIGS. 1 and 2 show a first embodiment. 1 is a longitudinal sectional view of the bearing, and FIG. 2 is a sectional view taken along line II-II of FIG. In the figure, 1 is a rotating shaft, and a metal bush 2b is a holder 2a.
Has been pressed into. The bush 2b is provided with a plurality of slits 2d in the axial direction over a length l, and the inner diameter of a part (the slit portion) inside the holder 2a is increased so that the length between the back surface of the bush 2b is increased. A gap 2c of δ is formed over the length l in the axial direction.

FIG. 3 shows a second embodiment, which is an example in which a part of the outer diameter of the bush 2b is made small along with the slit 2d of the first embodiment and a gap 2c is provided, which is exactly the same as the first embodiment. Have an effect. As a modification, when the bush 2b is a wound bush, the same effect as that of the first embodiment can be produced by aligning one slit 2d with the mating surface of the bush.

[0013]

When the hydraulic pump motor operates, the rotary shaft 1
However, a lateral load F is applied to the tilt bearing bush 2b. The bush deforms due to a lateral load, but by carrying out the present invention, the one-sided contact angle between the rotating shaft and the bush 2b is reduced and the one-sided contact is alleviated. In the present invention, a plurality of slits 2
Since d is provided, the bush 2b is easily deformed, and the one-sided alleviation ability is large. When the bush end is deformed by δ in the radial direction, the inner peripheral surface of the holder 2a comes into contact with the outer peripheral surface of the bush 2b, and further deformation can be prevented.

Therefore, the tilt angle α = δ / l can be absorbed in one contact. In the hydraulic pump motor, the inclination angle of the bearing of the rotary shaft can be predicted at the design stage, and if δ and l are determined so that the inclination angle matches the rotary shaft, it is possible to prevent one-sided contact between the bush and the rotary shaft. You can As a result, the bush and the rotary shaft can be fluid-lubricated, and damage such as seizure and wear can be prevented. Further, since the slide bearing can be used instead of the rolling bearing, the noise of the hydraulic pump motor can be reduced.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a slide bearing according to a first embodiment of the present invention,

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a longitudinal sectional view of a slide bearing according to a second embodiment of the present invention,

FIG. 4 is a vertical sectional view showing a conventional hydraulic pump.

[Explanation of symbols]

1 ... Rotary shaft, 2A, 2B ... Bearing, 2a ... Bush holder, 2b ... Bush, 2c ... Gap, 2d ... Slit, 3
... cylinder barrel, 4 ... valve plate, 5 ... swash plate, 6 ... piston, 7 ... shoe, 8 ... shoe retainer, 9 ... ball retainer, 10 ... casing, 11 ... seal, 12 ... spline.

Claims (1)

[Claims] 1. A main shaft slide bearing of a piston type hydraulic pump motor, wherein a plurality of slits are formed in a part of a bearing bush on a side that is one-sided against the rotary shaft, and the bush back surface or the bush press-fit holder side is formed. A spindle slide bearing for a hydraulic pump motor, characterized in that the axially corresponding portion of the slit is allowed to escape so that the bush back surface and the axially corresponding portion of the slit of the bush holder do not contact.