JP3392588B2 - Spindle bearings for hydraulic pump motors - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a main shaft slide bearing applied to a piston type hydraulic pump motor. 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 rotating shaft, 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 caulked to the spherical portion of the piston 6, 8 is a shoe retainer, 9 is a ball retainer. Reference numeral 10 denotes a casing, 11 denotes a seal, and 12 denotes a spline. [0003] The piston 6 is pressed against the swash plate 5 via the shoe 7 by the discharge pressure. As a reaction force, a force F is applied to the piston from the swash plate 5. The orthogonal component of the force to the rotating shaft 1 is applied to the rotating shaft 1 via the spline 12. The resultant force F of the forces from the plurality of pistons 6 is applied to the rotating shaft as a lateral load. Moreover, the lateral load F increases in proportion to the discharge pressure. [0004] The lateral load F causes the rotating shaft 1 to bend and deform, causing the bearings 2A and 2B to come into contact with each other. In order to prevent this one-side contact, a rolling bearing capable of absorbing one-side contact such as a spherical roller bearing or a roller bearing is used as a bearing in a hydraulic pump motor. However, when ordinary metal plain bearings are used for the bearings 2A and 2B, there is a problem that seizure and wear damage are apt to occur due to contact with one side. [0005] In a water / glycol-based hydraulic fluid pump motor, a sliding bearing is used because the life of the rolling bearing is short, but a resin bearing is used to prevent seizure due to one-side contact. Resin bearings prevent excessive one-sided contact due to deformation and wear to prevent seizure damage, but have the drawback that their life is not long due to 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 come into contact with each other. . In order to prevent the one-side contact, a spherical roller bearing or a roller bearing is used as a bearing in the hydraulic pump motor. However, when ordinary metal plain bearings are used for the bearings 2A and 2B, there is a problem that seizure and wear damage are liable to occur due to contact with one side. A water / glycol-based hydraulic fluid pump motor is made of a resin bearing in order to prevent seizure due to one-sided contact. However, the resin bearing has a drawback that its life is not long because of abrasion. ing. SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic pump motor capable of preventing a seizure or abrasion by absorbing and relaxing a contact of a bearing bush even when a large load acts on the rotating shaft in a lateral direction to deform the rotating shaft. The main object is to provide a plain bearing. A main shaft slide bearing of a hydraulic pump motor according to the present invention is a main shaft slide bearing of a piston type hydraulic pump motor, wherein an inner diameter supporting a rotary shaft is uniform.
Such in spindle sliding bearing of the hydraulic pump motor the outer periphery of the circular cylindrical bushing formed by press-fitted into the inner periphery of the holder, a plurality of over a predetermined length from the end face on the side of the contact rotating shaft piece in the bush When the slit is formed along the axial direction, a part of the outer diameter of the bush is reduced or
By increasing a part of the inner diameter of the holder , a constant gap is formed in the axial direction that has escaped between the outer periphery of the bush and the inner periphery of the holder over an equivalent length of the slit in the axial direction . Slit of the bush due to lateral load
At the portion corresponding to the axial length of the bush,
It is characterized in that it is configured to be deformable until it comes into contact with the inner peripheral surface of the holder . An axial bearing load F is applied to the bush 2b from the rotary shaft 1. In addition, the rotating shaft is flexed and deformed by the lateral load F, and is inclined with respect to the bush and makes one contact with the sliding bearing. The bush has a plurality of axial slits 2d,
Since a gap is provided between the back surface of the bush and the bush holder, the bush can be deformed along the inclination of the rotating shaft 1.
One side 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 amount of deformation of the bush 2b is regulated by the amount of the gap, thereby preventing the bush 2b from being damaged due to excessive bending deformation. An embodiment 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, reference numeral 1 denotes a rotating shaft, a metal bush 2b having a uniform inner diameter.
Are press-fitted into the holder 2a. A plurality of slits 2d are provided in the bush 2b in the axial direction over a length l, and the inside diameter of a part (the slit portion) inside the holder 2a is increased, and a radial direction is provided between the back surfaces of the bush 2b. A constant gap 2c in the axial direction having a length δ has a length l in the axial direction.
It is formed over. That is, in the first embodiment, as shown in FIGS.
The rotary shaft 1 is rotatably supported by a cylindrical bush 2b whose inner and outer diameters are press-fitted into the inner circumference of the cylindrical shaft and are uniform in the axial direction. A plurality of slits 2d are inserted from the end face of the holder 2a over a predetermined length l, and the inner periphery of the bush 2b and the inner periphery of the holder 2a are formed on the inner surface of the holder 2a over the length l corresponding to the axial direction of the slit 2d. A constant gap is formed in the axial direction of the radial length δ that has escaped, so that the back surface of the bush 2b does not contact the portion corresponding to the axial length 1 of the slit 2d on the inner surface of the holder 2a. FIG. 3 shows a second embodiment, in which a slit 2d and a part of the outer diameter of the bush 2b are made small and a gap 2c is provided together with the slit 2d of the first embodiment, which is exactly the same as the first embodiment. Has an effect. As a modification, when the bush 2b is a wound bush, the same effect as in the first embodiment can be produced by matching one slit 2d with the mating surface of the bush. When the hydraulic pump motor operates, the rotating shaft 1
However, a lateral load F is applied to the tilt bearing bush 2b. Although the bush is deformed due to a lateral load, by implementing the present invention, the angle of contact between the rotating shaft and the bush 2b is reduced, and the contact of the bush is reduced. In the present invention, a plurality of slits 2
Since d is provided, the bush 2b is easily deformed, and the ability to alleviate the one-side contact is large. When the end of the bush 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. Accordingly, the inclination angle α = δ / l can be absorbed by one side. In the hydraulic pump motor, the inclination angle of the bearing part of the rotating shaft can be predicted at the design stage, and if δ and l are determined so that the rotating shaft and the inclination angle match, it is possible to prevent the bush and the rotating shaft from hitting one side. Can be. As a result, fluid lubrication between the bush and the rotating shaft is possible, and damages such as seizure and wear can be prevented. Further, since a sliding bearing can be used instead of the rolling bearing, the noise of the hydraulic pump motor can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a sliding bearing according to a first embodiment of the present invention, FIG. 2 is a view taken in the direction of arrows II-II in FIG. 1, FIG. FIG. 4 is a longitudinal sectional view of a sliding bearing according to an embodiment, and FIG. 4 is a longitudinal sectional view showing a conventional hydraulic pump. [Description of Signs] 1 ... Rotating shaft, 2A, 2B ... Bearing, 2a ... Bushing holder, 2b ... Bushing, 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.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16C 17/00-17/26 F16C 21/00-27/08 F16C 33/00-33/28

Claims (1)

(57) A [Claims 1. A piston type hydraulic pump main shaft sliding bearing of the motor, the outer periphery of the bush supporting the inner diameter uniform circular cylindrical rotating shaft on the inner periphery of the holder In the main shaft slide bearing of the hydraulic pump motor which is press-fitted, a plurality of slits are formed in the bush along the axial direction over a predetermined length from the end face on the side of the bushing,
Part of the outer diameter of the bush is reduced or
By increasing the portion of da inner diameter, to form a predetermined gap in the axial direction escape between the inner periphery of the said bushing outer periphery and the holder over the axial length corresponding to the slit, the blanking
Axial length of the bush slit due to the lateral load of the bush
The outer peripheral surface of the bush at the portion corresponding to
A main shaft slide bearing for a hydraulic pump motor, which is configured to be deformable until it comes into contact with a peripheral surface .