JPH08200371A - Oil-retaining bearing - Google Patents

Abstract

PURPOSE: To regulate the passage of an impregnating lubricant by applying masking processing to the surface of a sintered oil-retaining bearing. CONSTITUTION: Masking processing 12 is applied to part of the surface of a circular sintered oil-retaining bearing 4 formed with a bearing section at the center. A lubricant is prevented from unnecessarily oozing from the surface of the bearing 4 and being dispersed, the durability of the oil-retaining bearing 4 is improved, and an oil film is satisfactorily formed against a thrust load. The shaft deflection of a rotary shaft can be prevented when a motor having the specification that no radial load is applied is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing impregnated with lubricating oil, which comprises an annular sintered oil-impregnated bearing having a bearing portion formed in the center thereof, and forcibly controls the circulation path of impregnated oil. It is an object of the present invention to provide an ideal oil-impregnated bearing.

[0002]

2. Description of the Related Art Oil-impregnated bearings are made of a porous metal body obtained by molding metal powder and then sintering it. By allowing lubricating oil to soak into the pores, frictional heat and pumping action due to the rotation of the rotary shaft are achieved. Due to the combined action of and, the lubricating oil in the bearing exudes to the sliding portion between the rotating shaft and the bearing, so-called self-lubricating action is performed. In this case, because many small holes are formed on the surface of the bearing, part of the lubricating oil oozes from the inner diameter side of the bearing to the outer diameter side again due to the effect of pressure generation when the oil film is formed. The oil film pressure is generated by the wedge effect due to the rotation of the rotating shaft, but this oil film pressure is reduced from the small holes on the surface, so it is possible to sufficiently maintain the oil film pressure on the load side. Difficult to fall into the boundary lubrication area.

Further, since the sliding bearing has an operating clearance peculiar to the sliding bearing, when operating under a condition where a load (radial load) in the direction perpendicular to the rotating shaft is not applied, the runout or runout of the rotating shaft is equivalent to the operating clearance. Is likely to occur and stable operation cannot be obtained. On the other hand, in order to address these difficulties, the present applicant has developed the latest technology for effectively retaining the lubricating oil component impregnated in the sintered oil-impregnated bearing in the sintered metal body. "Bearing made of sintered metal" (Jikkou 6-29536) is known. This consists of an outer powder compacted sintered metal part having a joint part projecting on one side of the annular inner powder compacted sintered metal part having a bearing part and a projecting joint part on the other side. The above-mentioned joints are joined to the other body, and a lubricating component reservoir is formed between both annular bodies.

[0004]

However, in the case of the above-mentioned conventional technique, firstly, although it is easy to form an oil film against a load (radial load) in the direction orthogonal to the rotating shaft, the rotating shaft The formation of an oil film against a load in the parallel direction (thrust load) is small and the allowable value is low. Secondly, in a spindle motor, that is, a motor with specifications that does not apply a radial load, rattling corresponding to the operating clearance occurs. As a result, there is a drawback that the shaft runout of the rotating shaft often occurs and the operation of the motor is hindered.

Thirdly, the supply of lubricating oil to the sliding portion of the oil-impregnated bearing is generally performed only by seeping out from the holes in the sliding surface on the inner diameter side (inner side). Since it becomes impossible to supply sufficient lubricating oil to fill the operating gap, rattling and runout of the shaft are likely to occur, and likewise often hinder the operation of the motor.
Fourthly, the above-mentioned holes for lubricating oil seeping out of the oil-impregnated bearing may reduce the hydraulic pressure of the sliding portion, and often cause the lubricating oil to be scattered to places where oil is disliked. There are various difficulties.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art and obtains an ideal oil-impregnated bearing by forcibly controlling the circulation path of impregnated oil. More specifically, the present invention relates to an annular oil-impregnated bearing in which a bearing portion is formed in the center, wherein a part of the surface of the sintered oil-impregnated bearing is masked.

The present invention also relates to an annular oil-impregnated bearing having a bearing portion formed in the center thereof, wherein the externally exposed surface in the use state is masked.

Further, according to the present invention, in an annular sintered oil-impregnated bearing in which a bearing portion is formed in the center, a tapered portion which gradually expands from a part of the inner peripheral surface of the sintered oil-impregnated bearing toward the axial end surface is formed. In addition, the present invention also relates to an oil-impregnated bearing characterized in that the surface of the sintered oil-impregnated bearing excluding at least the tapered portion is subjected to masking processing.

Further, according to the present invention, in an annular sintered oil-impregnated bearing having a bearing portion formed in the center, a stepped portion is formed on the axial end surface of the sintered oil-impregnated bearing, leaving a portion near the outer peripheral surface. In addition, the present invention also relates to an oil-impregnated bearing characterized in that the surface of the sintered oil-impregnated bearing excluding the stepped portion and the inner peripheral surface is subjected to masking processing.

Further, according to the present invention, in an annular sintered oil-impregnated bearing having a bearing portion formed in the center, masking is applied to the outer peripheral surface and the axial end surface of the sintered oil-impregnated bearing, and the bearing end surface is formed in the axial direction. The present invention also relates to an oil-impregnated bearing, which is characterized in that a relief groove is formed.

Further, according to the present invention, in an annular sintered oil-impregnated bearing in which a bearing portion is formed in the center, the outer peripheral surface and the axial end surface of the sintered oil-impregnated bearing are masked, and a part of the sintered oil-impregnated bearing is subjected. Also relates to an oil-impregnated bearing characterized in that an escape hole is formed so as to penetrate in the axial direction.

Further, according to the present invention, in an annular sintered oil-impregnated bearing in which a bearing portion is formed in the center, the outer peripheral surface and the axial end surface of the sintered oil-impregnated bearing are masked, and a part of the sintered oil-impregnated bearing is subjected. Also relates to an oil-impregnated bearing characterized by forming an escape hole penetrating in the axial direction and further forming an oil supply hole communicating from the outer peripheral surface to the inner diameter surface through the escape hole.

Further, according to the present invention, in an annular sintered oil-impregnated bearing in which a bearing portion is formed in the center, an axial supply groove is formed on the inner peripheral surface of the sintered oil-impregnated bearing, and the supply groove is formed. The oil-impregnated bearing is also characterized in that an escape groove is formed in the same axial direction on the outer peripheral surface within a range of 80 degrees on the sliding side of the sintered oil-impregnated bearing from the position to the symmetrical position. Concerned.

Further, according to the present invention, in an annular sintered oil-impregnated bearing having a bearing portion formed in the center, a part of the sintered oil-impregnated bearing is formed so as to be oriented in the axial direction. It also relates to oil-impregnated bearings.

[0015]

[Function] When a part of the surface of the sintered oil-impregnated bearing is masked, the lubricating oil does not meaninglessly exude and diffuse from the bearing surface, significantly improving the durability of the oil-impregnated bearing and at the same time The formation of an oil film against the load (thrust load) in the direction parallel to the rotary shaft on the circumferential surface is good, and shaft runout of the rotary shaft can be prevented especially when the motor is used in a motor that is not subject to radial loads.

Further, a tapered portion is formed which gradually expands from a part of the inner peripheral surface of the sintered oil-impregnated bearing toward the axial end surface, and at least the surface of the sintered oil-impregnated bearing excluding the tapered portion is masked. If it is applied, sufficient lubricating oil is supplied to fill the operating gap by leaching the lubricating oil only from the taper part or from the bearing inner surface and the taper part, thereby eliminating rattling and runout of the shaft. .

Furthermore, a stepped portion is formed on the axial end surface of the sintered oil-impregnated bearing while leaving a portion near the outer peripheral surface, and the surface of the sintered oil-impregnated bearing excluding the stepped portion and the inner peripheral surface is formed. When the masking process is performed, the lubricating oil is also supplied from the stepped portion, so that the slidability in the thrust direction can be improved. Further, masking is applied to the outer peripheral surface and the axial end surface of the sintered oil-impregnated bearing, and an escape groove is formed on the outer peripheral surface in the axial direction, or a part of the sintered metal body is penetrated in the axial direction. In the case of forming the escape hole, the oil-containing lubricating oil can escape from the above-mentioned escape groove when the hydraulic pressure is generated by the rotation. Since it can be pulled, vibration and whirling of the rotating shaft can be prevented.

Further, the outer peripheral surface and the axial end surface of the sintered oil-impregnated bearing are masked, and an escape hole penetrating in the axial direction is formed in a part of the sintered oil-impregnated bearing. When the oil supply hole communicating with the inner diameter surface is formed through the hole, the lubricating oil is supplied from the clearance hole to the sliding surface by the negative pressure generated by the operation of the rotating shaft.
Further, on the inner peripheral surface of the sintered oil-impregnated bearing, a supply groove directed in the axial direction is formed, and a symmetrical position from the position of the supply groove,
Alternatively, when a relief groove is formed in the same axial direction on the outer peripheral surface within the range of 80 degrees on the sliding side of the sintered oil-impregnated bearing from the symmetrical position, the rotary shaft is stable in the bearing part of the sintered metal body. The shaft runout can be eliminated due to the mechanical sliding.

Further, in the case where a part of the sintered oil-impregnated bearing which is oriented in the axial direction is formed, when the lubricating oil moves in the sintered metal body as the rotary shaft rotates, a part near the part is formed. Movement is restricted, and as a result, the hydraulic pressure of the sliding portion near the barrier can be increased.

[0020]

The specific contents of the present invention will be described below with reference to FIGS.
Describing on the basis of the embodiment shown in 8, the reference numeral 4 represents an oil-impregnated bearing which is an annular sintered oil-impregnated bearing in which a bearing 5 is formed in the center. FIG. 1 shows a usage state of an oil-impregnated bearing 4 according to a first embodiment of the present invention. A taper gradually expanding from a part of an inner peripheral surface of a sintered oil-impregnated bearing toward an axial end surface. The surface of the sintered oil-impregnated bearing excluding at least the tapered portion 6 is masked 12 while forming the portion 6.

In the masking process 12, when the lubricating oil impregnated in the sintered oil-impregnated bearing circulates in the sintered metal body, the masked portion is exposed to the outside from the surface of the sintered metal body. It is possible to use a co-sliding process that crushes the surface by sliding products together, a cutting process that crushes the surface with a cutting tool, or a cemented carbide. A method such as a chamfering process for rubbing the surface with a plate or a tool steel plate, a shot blasting process for hitting metal powder or particles on the product surface for blinding, and a coating process for coating the product surface with a resin or the like can be considered. In the figure, 1 is a rotary shaft, 2 is a bracket, and 3 is a thrust receiving plate.

In the case of the oil-impregnated bearing 4 according to the first embodiment, the axial oil-impregnated bearing is impregnated in the sintered oil-impregnated bearing because the axial end surface and the outer peripheral surface excluding the taper portion 6 are masked. Lubricating oil flows out only from the taper portion 6 and is drawn along the inner surface of the bearing portion 5 by the capillary force and drawn around the rotating shaft 1 which is within the operating clearance of the rotating shaft 1 as shown by the arrow. The drawn lubricating oil is absorbed from the bearing portion 5 into the sintered oil-impregnated bearing at any time by the rotation of the rotating shaft 1,
The outflow from the taper portion 6 described above is repeated again.

FIG. 2 shows a cross-sectional view of the oil-impregnated bearing 4 according to the second embodiment of the present invention in use, and a plan view of the upper part thereof. In this case, the outer peripheral surface and the axial end surface of the sintered oil-impregnated bearing are masked 12, and one escape groove 6 oriented in the axial direction is formed on the outer peripheral surface.

In the case of the oil-impregnated bearing 4 of the second embodiment, the oil pressure of the lubricating oil generated in the sintered oil-impregnated bearing due to the rotation of the rotary shaft 1 can escape from the relief groove 6 on the outer peripheral surface,
While the rotating shaft 1 is rotating, the rotating shaft 1 is pulled to the position near the escape groove 6 in the bearing portion 5.

FIG. 3 is a cross-sectional view of the oil-impregnated bearing 4 according to the third embodiment of the present invention in use. In this case, the sintered oil-impregnated bearing has a stepped portion 7 formed on the end surface in the axial direction of the sintered oil-impregnated bearing while leaving a portion 4a near the outer peripheral surface, and the stepped portion 7 and the inner peripheral surface (bearing portion) are removed. The surface of the sintered oil-impregnated bearing is subjected to a masking process 12.

In the case of the oil-impregnated bearing 4 of the third embodiment, as in the case of the first embodiment, the impregnated lubricating oil flows out only from the step portion 7 and is supplied into the bearing portion, so that it is slid in the thrust direction. The mobility is further improved.

FIG. 4 shows a cross-sectional view of the oil-impregnated bearing 4 according to a fourth embodiment of the present invention in use, and a plan view on the upper part thereof. In this case, the outer peripheral surface and the axial end surface of the sintered oil-impregnated bearing are masked 12, and the escape hole 8 penetrating in the axial direction is formed in a part of the sintered oil-impregnated bearing. .

In the case of the oil-impregnated bearing 4 of the fourth embodiment, the oil pressure of the lubricating oil generated in the sintered oil-impregnated bearing due to the rotation of the rotary shaft 1 can escape from the escape hole 8, and the rotary shaft 1
During rotation, is drawn to the position near the escape hole 8 in the bearing portion 5.

FIG. 5 shows a cross-sectional view of the oil-impregnated bearing 4 according to a fifth embodiment of the present invention in use, and a left side view of the left part thereof. In this case, the outer peripheral surface and the axial end surface of the sintered oil-impregnated bearing are masked 12, and the escape hole 8 penetrating in the axial direction is formed in a part of the sintered oil-impregnated bearing. An oil supply hole 9 communicating with the clearance hole 8 from the outer peripheral surface and the inner surface of the bearing portion 5.
Are formed.

In the case of the structure of the oil-impregnated bearing 4 of the fifth embodiment, in addition to the operation of the structure of the fourth embodiment described above, the negative pressure generated by the rotation of the rotary shaft 1 causes the bearing to pass from the oil supply hole 9 to the bearing. Sufficient lubricating oil is supplied to the inner surface of the portion 5 to achieve the dynamic pressure effect.

FIG. 6 shows a sectional view of an oil-impregnated bearing 4 which is a sixth embodiment of the present invention. In this case, the masking process 12 is applied only to the surface of the portion exposed to the outside when the oil-impregnated bearing 4 is in use.

According to the structure of the oil-impregnated bearing 4 of the sixth embodiment, when the oil-impregnated bearing 4 is used, unnecessary lubrication oil is prevented from flowing out from a portion exposed to the outside, and the durability of the oil-impregnated bearing 4 is improved. And the impregnated lubricating oil in the sintered oil-impregnated bearing is exclusively supplied to the oil supplement mechanism 13 which supports the oil-impregnated bearing 4.

FIG. 7 shows a sectional view of an oil-impregnated bearing 4 which is a seventh embodiment of the present invention. In this case, a part 10 of the sintered oil-impregnated bearing is formed with an engagement portion 10 directed in the axial direction. The function part 10 may be one that can regulate the movement of the lubricating oil circulating in the sintered oil-impregnated bearing. For example, a resin is press-fitted or adhered or inflow-cured into the sintered oil-impregnated bearing, or a metal body is press-fitted or adhered. Alternatively, it can be formed by a method such as caulking, welding, sinter joining, and screwing.

According to the structure of the oil-impregnated bearing 4 of the seventh embodiment, when the lubricating oil circulates in the sintered oil-impregnated bearing as the rotary shaft 1 rotates, the sliding portion near the barrier 10 Hydraulic pressure is increased.

FIG. 8 shows a sectional view of an oil-impregnated bearing 4 according to an eighth embodiment of the present invention. In this case, an oil supply groove 11 directed in the axial direction is formed on the inner peripheral surface of the sintered oil-impregnated bearing, and a position symmetrical with respect to the position of the oil supply groove 11,
Alternatively, the escape groove 6 is also formed in the axial direction in the outer peripheral surface within the range of 80 degrees on the sliding side of the sintered oil-impregnated bearing from the symmetrical position.

In the case of the oil-impregnated bearing 4 according to the eighth embodiment, the negative pressure generated by the rotation of the rotary shaft 1 causes sufficient lubrication oil to be supplied from the oil supply groove 11 to the inner surface of the bearing portion 5. The dynamic pressure effect can be achieved, and the hydraulic pressure of the lubricating oil generated in the sintered oil-impregnated bearing due to the rotation of the rotating shaft 1 can escape from the escape groove 6 on the outer peripheral surface. As a result, the rotary shaft 1 is more stably rotated and slid as a result of being pulled to the position near the escape groove 6 described above.

The present invention is not limited to the configuration of the above-mentioned embodiment, and in addition to this, for example, the above-mentioned first to first
The various configurations shown in the eighth embodiment may be combined appropriately.

[0038]

As described above, according to the present invention, since a part of the surface of the sintered oil-impregnated bearing is masked,
Lubricating oil does not seep out from the bearing surface, meaning that it does not diffuse, and the durability of the oil-impregnated bearing is significantly improved. Along with this, the formation of an oil film on the inner peripheral surface of the bearing part against a load (thrust load) in the direction parallel to the rotating shaft is improved, and shaft runout of the rotating shaft is prevented especially when it is used in a motor with no radial load specifications. be able to.

Further, a tapered portion is formed which gradually expands from a part of the inner peripheral surface of the sintered oil-impregnated bearing toward the axial end surface, and at least the surface of the sintered oil-impregnated bearing excluding the tapered portion is masked. If it is applied, sufficient lubricating oil is supplied to fill the operating gap by leaching the lubricating oil only from the tapered part or from the bearing inner surface and the tapered part, which causes shaft rattling and runout. By eliminating it, stable operation becomes possible.

Further, a stepped portion is formed on the axial end surface of the sintered oil-impregnated bearing while leaving a portion near the outer peripheral surface, and the surface of the sintered oil-impregnated bearing excluding the stepped portion and the inner peripheral surface is formed. When the masking process is performed, the lubricating oil is also supplied from the stepped portion, so that the slidability in the thrust direction can be improved. Further, masking is applied to the outer peripheral surface and the axial end surface of the sintered oil-impregnated bearing, and an escape groove is formed on the outer peripheral surface in the axial direction, or a part of the sintered metal body is penetrated in the axial direction. In the case of forming the escape hole, the oil-containing lubricating oil can be released from the above-mentioned escape groove when the hydraulic pressure is generated by the rotation, whereby the rotary shaft can be located in the bearing near the above-mentioned escape groove. Since it can be pulled, vibration and whirling of the rotating shaft can be prevented.

Further, the outer peripheral surface and the axial end surface of the sintered oil-impregnated bearing are masked, and an escape hole penetrating in the axial direction is formed in a part of the sintered oil-impregnated bearing. When an oil supply hole that communicates with the escape hole is formed, the negative pressure generated by the operation of the rotating shaft can supply sufficient lubricating oil from the escape hole to the sliding surface, significantly improving the durability of the oil-impregnated bearing. The dynamic pressure effect can be enhanced.

Further, a supply groove directed in the axial direction is formed on the inner peripheral surface of the sintered oil-impregnated bearing, and a position symmetrical to the position of the supply groove or a sliding side of the sintered oil-impregnated bearing from the symmetrical position by 80 degrees. In the case where an escape groove that is also oriented in the axial direction is formed on the outer peripheral surface within the range of (4), the rotating shaft stably slides in the bearing portion of the sintered metal body, so that shaft runout can be eliminated.

Further, in the case where a part of the sintered oil-impregnated bearing which is oriented in the axial direction is formed, when the lubricating oil moves in the sintered metal body as the rotary shaft rotates, the part near the part is formed. Movement is restricted, and as a result, the hydraulic pressure of the sliding portion near the barrier can be increased.

[Brief description of drawings]

FIG. 1 is a sectional view showing a usage state of an oil-impregnated bearing according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view and a plan view of an oil-impregnated bearing in use, which is a second embodiment of the present invention.

FIG. 3 is a sectional view of an oil-impregnated bearing in use, which is a third embodiment of the present invention.

FIG. 4 is a cross-sectional view and a plan view of an oil-impregnated bearing in use, which is a fourth embodiment of the present invention.

5A and 5B are a cross-sectional view and a left side view of an oil-impregnated bearing in use, which is a fifth embodiment of the present invention.

FIG. 6 is a sectional view of an oil-impregnated bearing, which is a sixth embodiment of the present invention.

FIG. 7 is a sectional view of an oil-impregnated bearing, which is a seventh embodiment of the present invention.

FIG. 8 is a sectional view of an oil-impregnated bearing, which is an eighth embodiment of the present invention.

[Explanation of symbols]

 1 rotary shaft 2 bracket 3 thrust receiving plate 4 oil-impregnated bearing 5 bearing part 6 taper part 7 step part 8 escape hole 9 oil supply hole 10 barrier part 11 oil supply groove 12 masking process 13 lubrication mechanism

Claims (10)

[Claims] 1. An oil-impregnated bearing having an annular sintered oil-impregnated bearing having a bearing portion formed in the center, wherein a part of the surface of the sintered oil-impregnated bearing is masked. 2. The oil-impregnated bearing according to claim 1, wherein the masking process is performed on the outer peripheral surface and / or the axial end surface of the annular oil-impregnated sintered oil-impregnated bearing. 3. An oil-impregnated sintered annular bearing having a bearing portion formed at the center, wherein an externally exposed surface in a used state is masked. 4. An annular sintered oil-impregnated bearing having a bearing portion formed in the center, wherein a tapered portion gradually expanding from a part of an inner peripheral surface of the sintered oil-impregnated bearing toward an axial end surface is formed, and An oil-impregnated bearing characterized in that the surface of a sintered oil-impregnated bearing excluding at least the tapered portion is subjected to a masking process. 5. An annular sintered oil-impregnated bearing having a bearing portion formed in the center thereof, wherein a stepped portion is formed on an axial end surface of the sintered oil-impregnated bearing while leaving a portion near the outer peripheral surface,
An oil-impregnated bearing characterized in that the surface of a sintered oil-impregnated bearing excluding the stepped portion and the inner peripheral surface is masked. 6. An annular sintered oil-impregnated bearing having a bearing portion formed in the center, wherein the outer peripheral surface and the axial end surface of the sintered oil-impregnated bearing are masked, and the outer peripheral surface is provided with an escape groove directed in the axial direction. An oil-impregnated bearing characterized by being formed. 7. An annular sintered oil-impregnated bearing having a bearing portion formed in the center thereof, wherein the outer peripheral surface and the axial end surface of the sintered oil-impregnated bearing are masked, and a part of the sintered oil-impregnated bearing is axially formed. An oil-impregnated bearing characterized in that a relief hole is formed so as to penetrate toward the. 8. An annular sintered oil-impregnated bearing having a bearing portion formed in the center thereof, wherein the outer peripheral surface and the axial end surface of the sintered oil-impregnated bearing are masked, and a part of the sintered oil-impregnated bearing is axially formed. An oil-impregnated bearing, characterized in that an escape hole is formed to penetrate toward the inner side of the bearing portion, and an oil supply hole communicating from the inner surface of the bearing portion to the inside of the escape hole is formed. 9. An annular sintered oil-impregnated bearing having a bearing portion formed in the center, wherein a supply groove directed in the axial direction is formed on the inner peripheral surface of the sintered oil-impregnated bearing, and symmetrical from the position of the supply groove. Position, or sliding side 8 of the sintered oil-impregnated bearing from the symmetrical position
An oil-impregnated bearing characterized in that an escape groove is formed in the outer peripheral surface within the range of 0 degree in the same direction as the axial direction. 10. An oil-impregnated sintered oil-impregnated bearing having a bearing portion formed in the center thereof, wherein a part of the sintered oil-impregnated bearing is formed with an engagement portion directed in the axial direction.