JPS6319623Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a dynamic pressure type radial thrust fluid bearing device, and particularly relates to an improvement of a thrust bearing member.

The housing includes a housing having a cylindrical hole, a thrust receiving member fitted into one end of the cylindrical hole with an interference fit, and a shaft rotatably and loosely fitted into the cylindrical hole, and the outer circumferential surface of the shaft and the cylindrical hole an asymmetric herringbone-shaped groove for generating dynamic pressure that is inclined only in one direction or has a longer length in one direction than in the other direction, and is provided between the outer circumferential surface and the cylindrical hole. A dynamic pressure membrane is formed on the groove to support the radial load, and the pressure fluid generated by the groove is guided between the thrust receiving surface of the thrust receiving member and the end surface of the shaft opposite to the thrust receiving surface. A hydrodynamic type radial thrust fluid bearing device in which a hydrodynamic film is formed between the thrust receiving surface and the end face to support the thrust load is known from Figs. 3 and 4 of JP-A No. 58-24615. It is being Furthermore, it has been proposed in Fig. 3 of JP-A-58-34227 that the thrust receiving member be made of a self-lubricating synthetic resin to suppress the torque to a small level during startup or low-speed rotation.

However, in the case of the conventional ones mentioned above,
If the bearing is used in a wide temperature range, for example from -20℃ to +80℃, the synthetic resin thrust bearing member will creep as the temperature changes from low to high temperature several times. In some cases, the fit with the housing became loose and the thrust receiving member fell out of the housing. or,
In order to reduce the starting torque of the bearing and increase its durability, it is necessary to increase the accuracy of the perpendicularity of the thrust bearing surface of the thrust bearing member to the axis, so the injection molded synthetic resin is machined to achieve the necessary accuracy. It was designed as a thrust receiving member that ensured the following. In this case, when the synthetic resin is chucked on a lathe, it is easily deformed, and in order to obtain good accuracy, the machining process requires devising a jig or reducing the amount of turning per turn.

SUMMARY OF THE INVENTION An object of the present invention is to provide a dynamic pressure type radial thrust fluid bearing device in which the thrust bearing member is difficult to fall off from the housing and is easy to machine.

In order to achieve the above object, the present invention includes a housing having a cylindrical hole, a thrust receiving member fitted into one end of the cylindrical hole, and a shaft loosely fitted into the cylindrical hole. A groove for generating dynamic pressure is provided in the outer circumferential surface or the cylindrical hole, a dynamic pressure film is formed between the outer circumferential surface and the cylindrical hole to support the radial load applied to the shaft or the housing, and the groove The pressure fluid generated is guided between the thrust receiving surface of the thrust receiving member and the end surface of the shaft opposite to the thrust receiving surface, and a dynamic pressure film is formed between the two surfaces to reduce the thrust load applied to the shaft or housing. The thrust bearing member is composed of a synthetic resin sliding member and a metal mounting member, and the sliding member is mounted on both end faces of the mounting member. The sliding member and the mounting member are integrally molded so that a portion thereof is covered, and as a result, the sliding member clamps and fixes the mounting member by the contraction force in the axial direction of the sliding member. The hydrodynamic radial thrust fluid bearing device is characterized in that the mounting member is fitted into the cylindrical hole.

Next, an embodiment of the present invention shown in the drawings will be described.

What is shown in FIG. 1 is a first embodiment of the present invention, which includes a housing 2 made of a metal material having a cylindrical hole 21, and a thrust receiving member 3 fitted and fixed to one end of the cylindrical hole 21.
This is a dynamic pressure type radial thrust fluid bearing device consisting of a shaft 1 made of a metal material and rotatably fitted loosely into a cylindrical hole 21. A herringbone-shaped dynamic pressure generating groove 11 (an inclined groove inclined only in one direction may be used) is formed on the outer peripheral surface of the shaft 1, the length of which is longer in one direction than the length in the other direction. . Note that this groove for generating dynamic pressure may be formed in the cylindrical hole 21. Due to this groove 11, when the shaft 1 rotates clockwise when viewed from above in the figure, or when the housing 2 rotates counterclockwise when viewed from above in the figure, a dynamic pressure film is formed between the outer peripheral surface of the shaft 1 and the cylindrical hole 21. , supports the radial load applied to the shaft 1 or the housing 2, and since the length of the herringbone-shaped groove 11 in one direction is longer than in the other direction, the pressure fluid generated by the groove 11 is transferred to the thrust receiving member 3. is pushed between the thrust receiving surface 311 and the end surface 12 of the shaft 1 facing the thrust receiving surface 311, and the both surfaces 311,
A dynamic pressure film is formed between the shaft 1 and the housing 2 to support the thrust load applied to the shaft 1 or the housing 2. In addition,
Since the end surface 12 comes into sliding contact with the thrust receiving surface 311 during startup or low-speed rotation, it is formed into a convex spherical surface for the purpose of reducing torque. The thrust receiving member 3 includes a sliding member 31 made of synthetic resin, and a sliding member 31 made of synthetic resin.
A mounting member 3 made of a metal material, which is integrally molded with the sliding member 31 on the radially outer side of the housing 2 and is made of a magnetic material and has a coefficient of linear expansion that is approximately the same as that of the housing 2.
It consists of 2. One end surface of the sliding member 31 faces the end surface 12 and serves as a thrust receiving surface 311 . The entire length of the mounting member 32 in the axial direction is shorter than the length of the sliding member 31, and a portion 312 of the sliding member 31,
The sliding member 31 and the mounting member 32 are integrally molded so that 313 forms an annular flange shape and is covered with the sliding member 31 and the mounting member 32. As a result, since the sliding member 31 is made of synthetic resin, the force of contraction in the axial direction during injection molding causes the mounting member 32 to
The sliding member 31 pinches them in the axial direction. The outer diameter 323 of the mounting member 32 is fitted into one end of the cylindrical hole 21 with an interference fit. Note that a hole 314 passing through the center of the sliding member 31 in the axial direction is a hole for adjusting the pressure of the dynamic pressure film between the end surface 12 and the thrust receiving surface 311 to an appropriate value.

What is shown in FIG. 2 is a second embodiment of the present invention, which includes a housing 2 having a cylindrical hole 21, a thrust receiving member 3 fitted and fixed to one end of the cylindrical hole 21, and a thrust receiving member 3 that is rotatably and loosely fitted into the cylindrical hole 21. This is a dynamic pressure type radial thrust fluid bearing device consisting of a shaft 1. A groove 11 for generating dynamic pressure is formed on the outer peripheral surface of the shaft 1, and functions similarly to the first embodiment to support radial and thrust loads. The thrust receiving member 3 of this embodiment includes a sliding member 31 made of synthetic resin,
A mounting member 32 is formed integrally with the sliding member 31 on the outside in the radial direction of the sliding member 31, and is made of a magnetic material and a metal material having approximately the same coefficient of linear expansion as that of the housing 2. Mounting member 32
One end surface 321 is larger than the end surface 12 of the thrust receiving surface 3.
11, an annular step 324 is formed on the other end surface 326, and a step end surface 322 is provided. Therefore, the axial length between the one end surface 321 of the mounting member 32 and the step end surface 322 is the same as that of the sliding member 3.
It is shorter than the entire axial length of 1.
The sliding member 31 and the mounting member 32 are integrally molded so that parts 312 and 313 of the sliding member 31 form an annular flange shape on the one end surface 321 and the stepped end surface 322. . As a result, as in the first embodiment, one end surface 321 of the mounting portion 32 and the step end surface 322, that is, both end surfaces, are connected to the sliding member 31.
are sandwiched, and the sliding member 31 is strongly fixed to the mounting member 32. The outer diameter 323 of the mounting member 32 fits into one end of the cylindrical hole 21 with a shimmy. Note that a flange portion 325 is formed on the mounting member 32, and the thrust receiving member 3 is positioned with respect to the housing 2 in the axial direction.

According to the present invention, although the thrust receiving surface is made of synthetic resin with good sliding properties, it is equipped with a mounting member made of a metal material that is integrally molded with the synthetic resin, and this mounting member is firmly attached to the housing. Can be mated,
The thrust receiving member does not creep as it is not affected by the contraction of the synthetic resin. Furthermore, if a metal material having substantially the same coefficient of linear expansion as the housing is used for the mounting member, the fitting angle will not change even if the operating environment temperature changes, and there is no fear that the thrust receiving member will fall off from the housing. Furthermore, if the mounting member is made of a magnetic metal material, a magnetic chuck can be used when machining the thrust receiving surface of the thrust receiving member, resulting in good machining accuracy and high machining efficiency. Furthermore, since the sliding member is attached by sandwiching the mounting member in the axial direction, there is no possibility that the sliding member will separate from the mounting member.

Note that the present invention is not limited to the mounting orientation of the bearing and the shape of the groove for generating dynamic pressure, etc. of the embodiment.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of the first embodiment of the present invention, and the second
The figure is a longitudinal cross-sectional view of a second embodiment of the present invention, with reference numeral 11
is a groove, 21 is a cylindrical hole, 3 is a thrust receiving member, 31
32 is a sliding member, 32 is a mounting member, 312 and 313 are parts of the sliding member, and 321 and 322 are end faces (step end faces).

Claims (1)

[Claims for Utility Model Registration] (1) A housing comprising a cylindrical hole, a thrust receiving member fitted into one end of the cylindrical hole, and a shaft loosely fitted into the cylindrical hole, the outer peripheral surface of the shaft being and a groove for generating dynamic pressure is provided in at least one of the cylindrical holes, a dynamic pressure membrane is formed between the outer peripheral surface and the cylindrical hole to support a radial load, and a pressure fluid generated by the groove is provided. is guided between the thrust receiving surface of the thrust receiving member and the end surface of the shaft opposite to the thrust receiving surface, and a dynamic pressure film is formed between the thrust receiving surface and the end surface to support the thrust load. In the dynamic pressure type radial thrust fluid bearing device, the thrust receiving member is composed of a sliding member made of synthetic resin and a mounting member made of a metal material having a hole in the center, and the sliding member passes through the hole and is attached at both ends. flange-like part 31
2, 313, a portion of which covers both end surfaces 321, 322 of the mounting member, the sliding member and the mounting member are integrally formed, and the mounting member is fitted into the cylindrical hole. A dynamic pressure type radial/thrust fluid bearing device characterized by: (2) The dynamic pressure type radial thrust fluid bearing device according to claim 1, wherein the linear expansion coefficient of the mounting member is substantially the same as that of the housing. (3) The dynamic pressure type radial thrust fluid bearing device according to claim 1, wherein the mounting member is made of a magnetic metal material.