JP2012149755A - Cage for rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive cage with machined portions provided for improving performances such as lubricity, low torque property, or the like by molding the cage by a MIM method, to improve the performances.SOLUTION: The cage for rolling bearing includes annular sections 13 formed at both axial ends, a plurality of pillar sections 14 each connecting the annular sections 13 at constant intervals, and pocket sections 15 arranged between the pillar sections 14. The machined sections such as oil supply grooves 17 provided for improving cage performances such as lubricity, low torque property, or the like are provided in some or all sections of the annular sections 13, the pillar sections 14, and pocket sections 15. The whole including the machined sections is molded by the MIM method.

Description

  The present invention relates to a rolling bearing cage, and more particularly to improvement of cage performance such as lubricity and low torque.

  Low-section and compact needle roller bearings (cages and rollers) are often used at the large end of the connecting rod of the engine and the planetary part of the planetary speed reducer. Is done. However, for example, in an engine, lubricating oil tends to be reduced in order to comply with exhaust gas regulations due to environmental problems in recent years, and the lubrication conditions of bearings are becoming more severe.

  Since the centrifugal force is applied to the cage by the eccentric motion at the large end of the connecting rod and the planetary portion, a cage with an outer diameter guide is often used. The outer diameter guide cage is guided while the cage outer diameter and the outer ring inner diameter surface are in sliding contact with each other. For this reason, when lubrication conditions become severe, oil film breakage may occur at the sliding contact portion on the outer diameter surface of the cage.

Taking the above points into consideration, it has been conventionally known to adopt the following structure as means for improving the lubrication performance of the cage.
A structure in which an oil supply groove reaching the axial end surface is provided on the outer diameter surface of the cage (Patent Document 1).
A structure in which oil supply grooves in the circumferential direction and the axial direction are provided on the outer diameter surface of the cage (Patent Document 2).
A structure in which a dynamic pressure groove is provided on the outer diameter surface of the cage (Patent Document 3).
・ Structure in which radial oil supply holes are provided in the cage pillars (Patent Document 4)

  On the other hand, rolling bearings such as roller bearings are generally composed of an outer ring, an inner ring (or shaft), rolling elements and a cage. In rolling bearings, it is extremely important to keep the rotational torque small. is important. However, since the cage for guiding the rollers rotates while slidingly contacting the inner and outer rings and the rollers, the sliding resistance is one of the factors that increase the rotational torque of the rolling bearing.

Therefore, the following structures are conventionally known as means for reducing the rotational torque of the cage.
A structure in which the cage is thinned to reduce the contact area with each part and reduce friction (Patent Document 5, “Prior Art” section).
A structure in which the cage is impregnated with lubricating oil (Patent Document 5, “Prior Art”).
A structure in which narrow grooves are closely arranged on the inner surface of the pocket to form an uneven shape (Patent Document 6).
A structure in which a spiral groove that advances in the length direction is provided in the pillar portion of the cage (Patent Document 7).
A structure in which corrugation is applied to both axial end faces of the cage (Patent Document 8).

  Further, a metal powder injection molding method (hereinafter referred to as “MIM method”) has been conventionally known as a processing method for a cage of a rolling bearing (see Patent Document 9 “Means for Solving the Problems”). reference). Briefly explaining the MIM method, a mixture of metal powder and a binder is injection-molded into a mold, and then degreased and sintered to evaporate the binder to produce a metal product (cage). The density of the metal is as high as 95% or more, and a characteristic close to that of an iron cage made of molten metal is obtained.

JP 2003-42163 A JP 2004-324844 A JP 2008-19937 A JP 2008-128404 A JP 2004-245278 A JP-A-8-184318 JP 2004-316670 A JP-A-8-200303 JP 2000-234623 A

  In the conventional measures for improving the lubrication performance of the cage, when the oil groove or the oil hole is provided in the cage, there is a problem that the machining cost is increased if it is provided by turning. Although there is a method of forming by pressing, there are restrictions such as not being able to cope with very deep grooves and complicated shapes. In addition, it is difficult to press a thin hole from the standpoint of mold durability in order to provide a radial oil supply hole in the column.

  On the other hand, in the conventional measures for reducing the rotational torque by the cage, reducing the thickness of the cage has a problem of reducing the strength of the cage. For example, when used in a connecting rod part of an engine, a planetary part of a planetary speed reducer, or the like, if a centrifugal force due to an eccentric motion (crank motion) is applied to the cage, there is a risk of overloading. In addition, the method of impregnating the cage with the lubricating oil has a drawback of high cost.

  Further, a structure in which fine grooves are arranged closely on the inner surface of the pocket to provide a concavo-convex shape, a structure in which a spiral groove is provided in the cage pillar, and a structure in which corrugation is applied to both end faces of the cage are all disclosed for resin cages. Structure. Resin cages are inferior to metal cages in strength and heat resistance, and also have disadvantages such as a large coefficient of thermal expansion, large shrinkage immediately after molding, and large dimensional changes over time. Therefore, it is difficult to use in a part where these characteristics are required, for example, a part having severe use conditions such as a connecting rod part of an engine.

  In the above-mentioned Patent Document 9, an invention for manufacturing a rolling bearing retainer by the MIM method is disclosed. The gist of the invention is that the metal formed by the MIM method has very small independent residual pores with a diameter of 2 μm to 30 μm. It has been improved.

  In the above invention, in order to improve the lubricity of the cage, the cage itself is molded by the MIM method without providing a special processing portion (for example, an oiling groove or an oiling hole) for improving the lubricating performance. The residual holes that are inevitably generated in the metal are used as they are to hold the lubricating oil. As a matter of course, the size, position, shape, density, etc. of the residual holes cannot be arbitrarily set.

  As described above, the invention disclosed in Patent Document 9 merely uses the characteristic that fine pores remain in the metal after molding as one of the characteristics of the MIM method. It cannot be said that it uses one characteristic that it has, that is, the ability to manufacture a metal product having a complicated shape in the same manner as the injection molding of synthetic resin using various metal materials.

  In view of this, the present invention has improved these various performances by molding a retainer that is actively provided with a processing section for improving the performance of the retainer such as lubricity and low torque by the MIM method. It is an object to provide a cage at a low cost.

  In order to solve the above-mentioned problems, the present invention is provided between an annular portion provided at both ends in the axial direction, a large number of pillar portions that connect the annular portions at regular intervals, and between the pillar portions. In a rolling bearing retainer constituted by a pocket portion, a processing portion for improving retainer performance such as lubricity and low torque is provided on a part or all of the annular portion, column portion, and pocket portion. The entire structure including the processed part is formed by the MIM method.

  The processed parts are classified into those having a function of improving the lubricity of the cage and those having a function contributing to low torque.

  As a function to improve the lubricity of the cage, an oil supply groove provided in the axial direction or circumferential direction on the outer diameter surface of the annular portion, and provided in the radial direction or circumferential direction on both axial end surfaces of the annular portion. There are oil supply holes provided in the radial direction in the pillar portions between the provided oil supply grooves and pockets. By these oil supply grooves and oil supply holes, the lubricating oil is guided to the sliding portion of the cage. Further, as other processing parts, there are innumerable oil sump parts distributed in the sliding part of the cage. The amount of oil in the sliding portion is increased by the lubricating oil retained in the countless oil sump portions.

  Moreover, there exists a dynamic-pressure groove | channel provided in the annular part outer-diameter surface as what has a function which contributes to the low torque property of a holder | retainer. An oil film is formed on the outer peripheral surface of the annular portion by the action of the dynamic pressure groove. Other processed parts include a circumferential rib provided on the outer diameter surface of the annular part, a corrugated uneven part provided on the guide surface of the pocket part, and a protrusion provided on the inner end face of the pocket part. Both reduce friction with the mating member and contribute to low torque.

  As described above, according to the present invention, a retainer having a processing portion for improving the lubricity and low torque performance of a retainer such as an oil supply groove, an oil supply hole, a dynamic pressure groove, and a corrugated uneven portion. Is molded by the MIM method, so that it is possible to provide a cage having excellent performance in terms of lubricity, low torque and the like at a low cost.

1A is a partially longitudinal side view of Embodiment 1, FIG. 1B is a plan view of the same, and FIG. 1C is a cross-sectional view taken along line X1-X1 of FIG. 1B. is there. 2A is a plan view of the second embodiment, and FIG. 2B is a cross-sectional view taken along line X2-X2 of FIG. Fig.3 (a) is a side view of Embodiment 3, FIG.3 (b) is a partial top view same as the above. FIG. 4 is a side view of the fourth embodiment. Fig.5 (a) is a partial top view of Embodiment 5, FIG.5 (b) is sectional drawing of a X3-X3 line same as the above. FIG. 6 is a plan view of the sixth embodiment. FIG. 7 is a plan view of a modification of the sixth embodiment. FIG. 8 is a side view of a modification of the sixth embodiment. FIG. 9 is a partial cross-sectional view of a modification of the sixth embodiment. FIG. 10 is a plan view of the seventh embodiment. FIG. 11 is a plan view of the eighth embodiment. FIG. 12 is a plan view of a modification of the eighth embodiment. Fig.13 (a) is a partial cross section figure of the modification of Embodiment 8, FIG.13 (b) is a partial top view same as the above. 14A is a plan view of a modification of the eighth embodiment, FIG. 14B is a cross-sectional view taken along line X4-X4 in FIG. 14A, and FIG. 14C is X5 in FIG. 14A. It is sectional drawing of a -X5 line.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
[Embodiment 1]

  A needle roller bearing 10 according to the first embodiment shown in FIG. 1 includes a cage 11 and a needle roller 12 held thereby. The cage 11 is made of a metal manufactured by the MIM method, and has a pair of annular portions 13 provided at both ends in the axial direction and a certain interval in the circumferential direction between the annular portions 13. It is provided with a column portion 14 provided and connecting the annular portions 13 to each other, and a pocket portion 15 provided between the column portions 14. A concave portion 16 is formed in the center portion of the outer diameter surface of the column portion 14.

  On the outer diameter surface of each annular portion 13, an axial oil supply groove 17 is provided between the end portion of each pocket portion 15 and the outer end portion in the axial direction. The portions including the oil supply groove 17, the pocket portion 15, the concave portion 16, and the like are simultaneously formed when the entire retainer 11 is formed by the MIM method.

  When the cage 11 is molded by the MIM method, the metal material can be freely selected. For example, aluminum, titanium, or magnesium material can be used, and these materials can reduce the weight of the cage 11. it can. Further, by using high-strength brass, it is possible to improve the initial conformability of the sliding surface of the cage 11 and further improve the lubrication performance. The use of stainless steel provides rust prevention performance, so it can be used in environments where rust is likely to occur, such as outdoors, and in environments where rust is not required, such as food machinery and semiconductor manufacturing equipment. .

  In addition, when an identification mark or stamp (product name, manufacturer name, manufacturing information, etc.) is to be provided on the retainer 11, the number of steps for stamping is increased with a normal cage and roller. Since the identification mark and the stamp can be formed at the same time, it is not necessary to add a process and can be provided at low cost.

When the needle roller bearing 10 is used and supplied with lubricating oil, the lubricating oil in contact with the outer diameter surface of the cage 11 is captured by the oil supply groove 17 and is therefore guided to the pocket portion 15 side. This facilitates the lubrication performance of the cage 11.
[Embodiment 2]

  The cage 11 constituting the needle roller bearing 10 according to the second embodiment shown in FIG. 2 is provided with circumferential oil supply grooves 17 in the left and right annular portions 13. Other configurations are substantially the same as in the case of the first embodiment (see FIG. 1) except that there is no recess 16.

  The oil supply groove 17 is formed in a spiral shape, and one end thereof is at the outer end of the annular portion 13 and the other end is at the inner end. As shown in the figure, the direction of the spiral is determined to be counterclockwise for the left annular portion 13 and clockwise for the right annular portion 13. These oil supply grooves 17 guide the lubricating oil on the annular portion 13 in the spiral rotation direction.

When the direction of the spiral is set as shown in the figure, when the cage 11 rotates counterclockwise as viewed from the direction of arrow A in FIG. A flow of lubricating oil induced to the (pocket 15 side) occurs.
[Embodiment 3]

The cage 11 constituting the needle roller bearing 10 according to the third embodiment shown in FIG. 3 is provided with radial oil supply grooves 17 at a plurality of locations at predetermined intervals in the circumferential direction on both end surfaces thereof. is there. In this case, the lubricating oil is caused to flow by the centrifugal force accompanying the rotation of the cage 11, the amount of lubricating oil at the cage end surface is increased, and the oil permeability in the radial direction is improved.
[Embodiment 4]

  The retainer 11 constituting the needle roller bearing 10 according to the fourth embodiment shown in FIG. 4 is provided with circumferential oil supply grooves 17 on both end faces thereof. The oil supply groove 17 is formed in a spiral shape, and one end thereof is on the inner diameter of the end face of the annular portion 13 and the other end is on the outer diameter. The direction of the spiral is clockwise as shown in the figure from the inner diameter side to the outer diameter side, while the illustration of the other is omitted, but the other is counterclockwise from the inner diameter side toward the outer diameter side. Determined. These oil supply grooves 17 guide the lubricating oil adhering to the end face of the annular portion 13 in the spiral rotation direction.

  When the direction of the spiral is set as described above, when the cage 11 rotates counterclockwise as viewed from the direction of FIG. 4, it is guided from the inner diameter side to the outer diameter side also by the oil supply grooves 17 on both sides. Resulting in a flow of lubricating oil.

As in the case of the third embodiment (see FIG. 3), when the oil supply groove 17 is provided in the radial direction, a part of the oil adhering over the entire circumference of the end face can be guided in the outer radial direction. In the case of the fourth embodiment (see FIG. 4), the oil supply groove 17 is provided on the entire periphery, so that the oil on the entire periphery can be guided.
[Embodiment 5]

A cage 11 constituting the needle roller bearing 10 according to the fifth embodiment shown in FIG. 5 includes a column portion 14 and an annular portion 13 continuous to the column portion 14 as a processing portion that improves the lubrication performance of the cage 11. The radial oil supply holes 18 are provided at several locations. Since the lubricating oil can freely pass through these oil supply holes 18 in the radial direction, the lubricating performance of the cage 11 is improved.
[Embodiment 6]

  The cage 11 constituting the needle roller bearing 10 according to the sixth embodiment shown in FIGS. 6 to 9 is a counterpart member such as an outer ring or a casing disposed close to the outer peripheral portion or both ends of the cage 11. Innumerable oil reservoirs 19 are provided in a dispersed manner at the sliding portion with the needle roller 12 and the sliding portion with the needle roller 12. The oil sump 19 is formed by a circular or elliptical depression (dimple).

  In the case of FIG. 6, FIG. 7, it has provided in the end surface of the annular part 13 in the case of FIG. In the case of FIG. 9, it is provided on the guide surface of the pocket 15. The shape is not limited to a circle and an ellipse, and may be a square or a rectangle. In the case of an ellipse and a long direction, the long axis direction is set to be along the axial direction of the cage.

These oil sumps 19 provide resistance to the flow of the lubricating oil, the lubricating oil stays, the amount of oil in the sliding portion increases, and the oil film forming ability is improved.
[Embodiment 7]

  The cage 11 constituting the needle roller bearing 10 according to the seventh embodiment shown in FIG. 10 is provided with dynamic pressure grooves 20 on the outer peripheral surfaces of the left and right annular portions 13. In the illustrated example, the dynamic pressure groove 20 has a herringbone shape, but may have other shapes.

When the needle roller bearing 10 rotates at a high speed, an oil film is formed by the action of the dynamic pressure groove 20 between other members such as a casing disposed close to the outer peripheral surface of each annular portion 13, and rotational torque Is reduced.
[Embodiment 8]

  The retainer 11 of the needle roller bearing 10 according to the eighth embodiment shown in FIGS. 11 to 14 is connected to a counterpart member such as an outer ring and a casing disposed close to the outer peripheral portion and both end portions of the retainer 11. Protruding portions 21 are provided on the sliding portions and the sliding portions with the needle rollers 12, and contact with the protruding portions 21 reduces the sliding resistance and reduces the rotational torque of the cage 11.

  In the case of FIG. 11, a plurality of rib-shaped protrusions 21 are provided over the entire outer circumference of the left and right annular portions 12. The contact between each protrusion 21 and the mating member is a point contact, and friction is reduced.

  In the case of FIG. 12, a large number of protrusions 21 are provided on the entire circumference of each end face of the left and right annular portions 12 by corrugated uneven surfaces. The contact between each protrusion 21 and the mating member is a line contact.

  In the case of FIG. 13, a plurality of protrusions 21 are provided on the guide surface of the pocket portion 15 by corrugated surfaces in the axial direction. Contact between each protrusion 21 and the needle roller 12 is point contact.

  In the case of FIG. 14, a single protrusion 21 is provided on the inner end surface of the pocket portion 15 so as to be in contact with the center portion of both end surfaces of the needle roller 12. Since the central portion has a low peripheral speed and a small contact area, the sliding resistance is reduced and the rotational torque is reduced.

DESCRIPTION OF SYMBOLS 10 Needle roller bearing 11 Cage 12 Needle roller 13 Annular part 14 Column part 15 Pocket part 16 Recessed part 17 Oil supply groove 18 Oil supply hole 19 Oil reservoir 20 Dynamic pressure groove 21 Protrusion part

Claims (13)

  In a rolling bearing cage comprising an annular portion provided at both axial end portions, a plurality of column portions that connect the annular portions at regular intervals, and a pocket portion provided between the column portions. In addition, a part or all of the annular part, column part, and pocket part is provided with a processing part for improving cage performance such as lubricity and low torque, and the whole including the processing part is formed by the MIM method. A cage for a rolling bearing characterized by being molded.   The rolling bearing retainer according to claim 1, wherein the processed portion is an oil supply groove provided in an axial direction or a circumferential direction on an outer diameter surface of the annular portion.   The rolling bearing retainer according to claim 2, wherein the oil supply groove provided in the circumferential direction has a spiral shape.   The rolling bearing retainer according to claim 1, wherein the processed portion is an oil supply groove provided in a radial direction or a circumferential direction on both axial end surfaces of the annular portion.   The rolling bearing retainer according to claim 4, wherein oil supply holes provided in a circumferential direction on both end faces in the axial direction have a spiral shape.   The rolling bearing retainer according to claim 1, wherein the processed portion is an oil supply hole provided in a radial direction in a column portion or an annular portion between the pockets.   The rolling bearing retainer according to claim 1, wherein the processed portion is an infinite number of oil sump portions distributed in a cage sliding portion.   The rolling bearing cage according to claim 1, wherein the processed portion is a dynamic pressure groove provided on the outer diameter surface of the annular portion.   The rolling bearing retainer according to claim 1, wherein the processed portion is a circumferential rib-shaped protrusion provided on an outer diameter surface of the annular portion.   The rolling bearing retainer according to claim 1, wherein the processed portion is a protruding portion having a corrugated uneven surface provided on an end surface of the annular portion.   The rolling bearing retainer according to claim 1, wherein the processed portion is a protrusion formed by a corrugated surface in an axial direction provided on a guide surface of the pocket portion.   The rolling bearing retainer according to claim 1, wherein the processed portion is a single protrusion provided on the inner end face of the pocket portion. The rolling bearing retainer according to any one of claims 1 to 12, wherein the material for the MIM processing is any one of aluminum, titanium, magnesium, high-strength brass, and stainless steel.

Images