JPS61206823A - Manufacture of bush for floating bush bearing - Google Patents

Abstract

PURPOSE:To enable easy manufacture of the floating bush of a bearing, by a method wherein, after the inner peripheral surface of a cylinder bush material is machined in roundness in a state in that the material is pressed for resilient deformation, the deformation is released to for plural arcuate surfaces are formed in the inner peripheral surface. CONSTITUTION:The outer peripheral surface of a cylinder bush material 10a having an inner and an outer peripheral surface in roundness is supported in plural spots by means of projections 23a, 23b, 24a, and 24b of a securing tool 20. The projections 23a and 23b are pressed through a press screw 21 and a force gauge 22 to resiliently deform the bush material 10a. With this,the inner peripheral surface of the bush material 10a is machined in roundness, and thereafter, the bush material is released from the press produced by means of the projections 23a and 23b to provide a bush having plural arcuate surfaces.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a bush for a floating bush bearing that floats between a rotating shaft and a support supporting it by the dynamic pressure of lubricating oil.

5, which shows the structure of a conventional floating bush bearing, there is a gap between the outer circumferential surface 1a of the rotating shaft 1 and the inner circumferential surface 2a of the support 2 that surrounds and supports the rotating shaft. There is a gap 3 between the two
．． 4, a cylindrical bush 5 is interposed so as to be rotatable relative to the rotating shaft 1. When the shaft 1 starts rotating, dynamic pressure is generated in the lubricating oil supplied to the gap 4, and P
As the rotating shaft 1 floats inside the bush 5, the viscosity of the lubricating oil causes the bush 5 to rotate around the same rotation, and dynamic pressure is generated in the lubricating oil supplied to the gap 3, causing the bush 5 to also become a support. This results in a bearing with low frictional resistance as a whole.

In conventional floating bush bearings, the inner and outer circumferential surfaces of the bush are formed into a perfect circle with a gap between them, so if the bearing rotates above a certain number of rotations, it will generate oil whip and fail. When the bushing was in a stable state, there was a problem in which radial vibration occurred and the bushing came into contact with the rotating shaft or support.

Therefore, as a highly reliable floating bush bearing, in which the bush floats stably without vibration even when rotating at higher speeds than conventional models, multiple arcuate surfaces with different centers of one curve are formed in the circumferential direction. A floating bush bearing using a bush whose inner peripheral surface is formed into a continuous shape has been considered.

<Problems to be Solved by the Invention> When manufacturing a bush for a floating bush bearing whose inner circumferential surface is formed by a plurality of arcuate surfaces, the conventional processing method requires a lot of time and effort to manufacture it. Moreover, there were problems such as the need for advanced technology to manufacture high-precision products.

Based on this knowledge, it is an object of the present invention to provide a method by which a bush having a special inner peripheral surface shape for a floating bush bearing can be manufactured simply and with high precision.

<Means for Solving the Problems> The present invention provides for the outer circumferential surface of a cylindrical bushing material having a perfect circular inner circumferential surface and an outer circumferential surface concentrically formed at a plurality of locations in the circumferential direction. The bushing material is elastically deformed by pressing the supporting positions radially inward, and in this state, the inner circumferential surface is processed into a perfect circle, and then the support of the outer circumferential surface is released and the bush material is returned to its original state. The inner circumferential surface is formed by a plurality of arcuate surfaces.

Action〉 When the bushing material is pressed to its radius, the bushing material is elastically deformed into a distorted shape corresponding to this pressing force and the pressing position. Since the amount of processing on this inner circumferential surface is not uniform along the circumferential direction, a plurality of arcuate surfaces are formed on the inner circumferential surface of the bushing material by returning it to its original state.

Embodiment> As shown in FIG. 1, which shows an example of the structure of the floating bushing that is the object of the present invention, there is a gap 3. A cylindrical bush 10 is interposed between C and C, and the inner peripheral surface of this bush 10 is C
It is formed into a shape in which circular arc surfaces 11a and llb are continuous. The centers of curvature of these arcuate surfaces 11a and llb are eccentric in opposite directions relative to the center of the outer peripheral surface of the bushing 10, and vary depending on the diameter and rotation speed of the rotating shaft l, for example, about 200 millimeters. In the case of the rotating shaft 10 having a diameter of , the eccentricity is set to about 1/10 balm.

A floating bush bearing using such a bush 10 can rotate the bush 1 by rotating the shaft 1 once.
0 rotates in a state where it floats across a gap 3.4. However, during this rotation, the shape of the oil film within the gap 4 changes, and even at higher rotational speeds at which oil whip occurs, vibrations are prevented from occurring.

When manufacturing this bushing 10, a cylindrical bushing material 10 having a perfectly circular outer peripheral surface and an inner peripheral surface formed concentrically is used.
A is prepared, and 108% of the bushing material is supported inside a cylindrical bushing fixing jig 20 as shown in FIG.

A set screw 21 for applying an external force is screwed into the bush fixing jig 20 so as to pass through it in the radial direction.

A bush support 23 is connected to the tip of the force gauge 22.
is provided. A pair of pressing protrusions 23a and 23b are protruded from this bush support 23, and these pressing protrusions 23a
, 23b are also integrally protruded from the inner circumferential surface of the fixing jig 20 at positions 180 degrees apart from the bushing fixing supports 24a, 24b. Tsumashi, these protrusions 23a.

Between 23 b, 24 a, 24 b
After supporting the material 10a, the force gauge 22 (!:
The elasticity of the bushing material 10a is adjusted by adjusting the screwing amount of the set screw 21 while measuring the external force applied to the bushing support 23 using the attached eave side device. to press the target. Then, when the external force reaches a predetermined level, the bushing material 10a is turned or internally ground. This process involves turning or grinding the portion of the bushing material 10a that protrudes inward due to elastic deformation to ensure that the inner peripheral surface is true. Do it so that it becomes a circle d.

After processing in this manner, the set screw 21 is loosened and the bushing material 10a is taken out from within the fixing jig 20. At this time, the bushing material 10a returns to its original external shape due to its own elasticity.

The two parts protruding from the inner surface during elastic deformation and being ground remain as separate arcuate surfaces, yielding a bushing 1° having an inner circumferential surface in which the two arcuate surfaces are continuous.

Further, as shown in FIG. 3, the inner peripheral surface has three arcuate surfaces 13a,
When manufacturing a bushing support 2 having a continuous shape of 13b and 13a%, as shown in FIG.
A fixing jig 27 is used in which the bushing support 26 is integrally provided in a protruding manner, and the bushing support 26 is attached to the inner end of the set screw 21 via the force gauge 22 in the same way as in the previous embodiment. The bushing material 10a is supported by the three points of the light weight pressing protrusion 26a and the bushing fixing supports 25a and 25b, and the bushing material 10a is further screwed in by screwing in the set screw 21.
It is preferable to press the outer circumferential surface of a at three points to elastically deform it, and in this state process the inner circumferential surface into a perfect circle.

<Effects of the Invention> According to the method for manufacturing a bush for a floating bush bearing of the present invention,
The bushing material is pressed to elastically deform, and in this state, the inner circumferential surface of the bushing material is processed into a perfect circle, and this inner circumferential surface is formed into a shape with multiple continuous circular arc surfaces, so it is always true. It is only necessary to perform circular machining, and complex arcuate surfaces can be easily machined with a high-performance block.Furthermore, minute molding is possible by adjusting the amount of elastic deformation, and high-performance floating bush bearings can be obtained. can.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of an example of a floating bush bearing that is the object of the present invention, Fig. 2 is a conceptual diagram showing the manufacturing principle of the bush, Fig. 3 is a sectional view of another example of the bush, and Fig. 4 The figure is a conceptual diagram showing the manufacturing principle of this bushing, and FIG. 5 is a longitudinal sectional view of a conventional floating bush bearing. 10 is a bushing s, 10a is a bushing material, 20.27 is a fixing jig, 21 is a set screw, 22 is a force gauge %23.26 is a bushing support, 23a, 23b,
26a is a pressing protrusion. 24 a, 24 b, 25 a, 25 b
is a bushing fixed support.

Claims (1)

[Claims] The outer circumferential surface of a cylindrical bushing material, each having a perfectly circular inner circumferential surface and an outer circumferential surface formed concentrically, is supported at a plurality of locations in the circumferential direction, and these supporting positions are pressed radially inward to support the bushing. After elastically deforming the material and processing the inner circumferential surface into a perfect circle in this state, the outer circumferential surface is released from support and restored to its original shape, and the inner circumferential surface is formed by a plurality of circular arc surfaces. A method for manufacturing a bushing for a floating bushing bearing, characterized by: