JPH0949525A - Solid lubrication roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply lubricating oil directly to a track surface by forming a guide part for guiding in contact with the track surface of an inner or outer ring of a holder. SOLUTION: A bearing is composed of an inner ring 1 fitting on a rotary shaft, an outer ring 2 fixed to a housing, a plurality of balls 5 interposed between a track surface 3 of the inner ring 1 and a track surface 4 of the outer ring 2 and a holder to hold the balls 5 at equal intervals on circumference. Since a guide part 12 makes contact with the track surface 3 of the inner ring in the rotation of the bearing, lubricating powder of COPNA resin is rollingly supplied to the track surface 3 of the inner ring from the holder. The rollingly deposited film is not indirectly supplied through the ball 5, but direcly supplied from the holder 6 to the track surface 3 of the inner ring, so that the film is formed surely satisfactorily, and since the film is also rollingly supplied to the ball, the lubricating condition of the bearing can be markedly improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid lubrication rolling bearing suitable for use in a special environment where a lubricant such as grease or oil cannot be used, for example, in a high temperature, clean environment or in vacuum.

[0002]

2. Description of the Related Art As solid lubricants used for rolling bearings, inorganic materials such as silver and molybdenum disulfide and organic materials such as polytetrafluoroethylene (PTFE) and polyimide are generally used. Since it is formed as a film on the surface of the bearing component, it wears hard and
Difficulty in durability compared to grease lubrication.

In view of this point, the present inventors have previously proposed a rolling bearing in which a bearing component such as a bearing ring is made of Kopuna resin (Japanese Patent Application No. 7-14279). According to this proposal, since the bearing component itself is made of a resin material having a self-lubricating action, the durability can be remarkably improved as compared with the case of forming the solid lubricating coating. Moreover, since the COPNA resin has extremely excellent properties such as heat resistance and wear resistance, it is convenient as a bearing used under high temperature and clean environment such as semiconductor manufacturing equipment.

However, in the bearing using the bearing ring made of Kopuna resin, since the resin material is used as the mechanical structural member, the load resistance is inferior to the usual iron-based material,
There is also a problem that it is difficult to obtain high dimensional accuracy.

Therefore, the present inventors have previously proposed that the cage be made of Kopuna resin (Japanese Patent Application No. 7-76974) to solve these problems. According to this bearing, when the rolling element comes into contact with the cage, the lubricating powder of the coplanar resin is transferred to the rolling element, and further, this is transferred and supplied to the raceways of the inner ring and the outer ring via the rolling element. Sufficient lubricity can be ensured for each contact portion. Therefore, the inner ring and the outer ring can be made of an iron-based material, which makes it possible to obtain desired dimensional accuracy and load resistance.

[0006]

Generally, the lubricity of a solid lubrication bearing is greatly influenced by the quality of the transfer of the solid lubricant to the raceway surface and the like. However, in Japanese Patent Application No. 7-76974, the solid lubricant is first transferred to the rolling elements and then transferred to the raceway surface, which is indirectly used. If the conditions are severe, the lubrication of the raceway surface may be insufficient.

Therefore, an object of the present invention is to provide a solid-lubricated rolling bearing capable of directly supplying the lubricant to the raceway surface.

[0008]

To achieve the above object, a bearing according to the present invention comprises an inner ring and an outer ring, a plurality of rolling elements interposed between the inner and outer rings, and a self-lubricating material. A solid-lubricating rolling bearing comprising a cage for holding moving bodies at predetermined intervals, the cage having a guide portion that is guided in contact with the raceway of the inner ring or the outer ring.

A solid lubricated rolling bearing having an inner ring and an outer ring, a plurality of rolling elements interposed between the inner and outer rings, and a cage made of a self-lubricating material and holding the rolling elements at predetermined intervals. The cage is composed of a partial body including an inner ring side guide portion which is contact-guided to the raceway surface of the inner ring and a partial body including an outer ring side guide portion which is contacted and guided to the raceway surface of the outer ring.

The guide portion has an arcuate cross section, and its surface curvature is smaller than that of the raceway surface.

The cage is made of Kopuna resin.

Here, the term "copna resin" means naphthalene,
It refers to a thermosetting resin obtained by crosslinking a polycyclic aromatic hydrocarbon such as anthracene, phenanthrene, pyrene, and coal tar pitch with para-xylylene glycol using an acid catalyst. The reaction proceeds by an electrophilic substitution reaction involving dehydration, resulting in a structure in which a large number of fused polycyclic aromatic groups are linked by a penzyl type bond,
Condensed polycyclic polynuclear aromatic resin "Co ndensed P oly n uclear A rom
It is named "atic Resin". As an abbreviation, the underlined parts are collectively called "COPNA resin".

The Copuna resin is excellent in heat resistance, sliding characteristics, mechanical characteristics and chemical resistance, and has easy moldability and cost performance. Kopuna resin is currently marketed by Sumikin Kako Co., Ltd. under the trade name of "SK Resin".

In terms of heat resistance, the weight loss of phenol resin and polyimide resin, which have excellent heat resistance, begins at 300 ° C to 350 ° C, while that of Copuna resin (SK resin) is 40%.
Only when the temperature exceeds 0 ° C, the weight begins to decrease, and it exhibits extremely excellent thermal decomposition resistance.

Regarding the sliding property, the limit PV value of the one without the filler is 2000 kgf / cm ² · cm / s, and that of the composite material with PTFE or graphite is 2800 to 4400 kgf / cm ² · cm / s. is there. Furthermore, the limit PV value of the heat-treated product is 6250 kgf / cm ² · cm / s
It has been confirmed that the above-mentioned results reach the level of 4500 to 5500, which is a polyimide composite material having excellent sliding characteristics, and exhibits excellent sliding characteristics.

The specific wear amount is 0.02 mm for the graphite-added product.
It is about ² / kgf · km, which is a material with excellent wear resistance.

Regarding easy moldability, since it exhibits sufficient fluidity even at about 100 ° C., transfer molding as well as injection molding and laminated molding can be applied, and molding can be performed under almost the same conditions as phenol resin, and mass production is supported. Is also possible.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is applied to a deep groove ball bearing, and an embodiment thereof will be described below with reference to FIGS. 1 to 8.

As shown in FIG. 1, this bearing includes an inner ring (1) fitted to a rotating shaft (not shown), an outer ring (2) fixed to a housing (not shown), and a raceway surface (1) of the inner ring (1). 3) and a plurality of rolling elements (balls) (5) interposed between the raceway surface (4) of the outer ring (2) and a cage (6) for holding the balls (5) at equal intervals around the circumference. Composed. 1 (a) is an axial sectional view passing through the comb portion (11) of the cage (6) described later, and FIG. 1 (b) is an axial sectional view passing through the center of the ball (5). is there.

Inner and outer rings (1) (2) and balls (5)
Is made of an iron-based material such as martensitic stainless steel, for example, SUS440C, in order to obtain desired load resistance and dimensional accuracy, and the retainer (6) is formed of the above-described Kopuna resin.

The retainer (6) has a crown-like shape and is formed at least in an annular portion (10) and a comb-like portion integrally formed with the annular portion (10) for holding the ball (5) at a distance. (11) consists of The axial length of the comb portion (11) is approximately the same as the width of the inner ring raceway surface (3) and the outer ring raceway surface (4).

By the way, generally, the cage (6) is roughly classified into three types, that is, rolling element guide, inner ring guide and outer ring guide, depending on the type of guiding the rotational movement thereof. The rolling element guide uses the orbital movement of the rolling element (5) to rotate the cage (6) so that the inner and outer diameter surfaces of the cage (6) do not touch the inner and outer rings (1) and (2). It is a guide. The inner ring guide guides the rotational movement of the retainer (6) by rotating the inner ring (1) by bringing the inner diameter surface of the retainer (6) into contact with the inner ring (1: rotation side), and the outer ring guide is Rotation of the retainer (6) by the revolution movement of the rolling element (5) while applying the braking action to the retainer (6) by bringing the outer diameter surface of the retainer (6) into contact with the outer ring (2: fixed side). It guides the exercise.

Among these guide types, the inner ring guide and the outer ring guide are, in a normal bearing, the inner diameter surface or the outer diameter surface of the retainer (6) and the shoulder portions (1a) (of the inner and outer rings (1) and (2)). Although it is performed by contacting the inner ring raceway surface (3) or the outer ring raceway surface (4) in the present invention, it is performed by contacting the inner ring raceway surface (3).

Specifically, for example, in the inner ring guide type, as shown in FIGS. 1 (a) and 1 (b), the inner surface of the comb portion (11) of the retainer (6) is arcuate toward the inner diameter side. The protruding guide part (12) is integrally formed. The guide portion (12) is formed on the inner diameter surface of all the comb portions (11), as shown by the scattered points in FIG.

The minimum inner diameter (φh) of the guide portion (12) is slightly larger than the minimum outer diameter (φg) of the inner ring raceway surface (3) (φh> φg). The partial contact of the inner ring raceway surface (3) with the inner ring (12) (see FIGS. 1A and 1B) guides the rotational movement of the cage (6).

The surface curvature (R _R ) of the guide portion (12) is such that the guide portion (12) can contact the axial center portion (P) of the inner ring raceway surface (3). It is made smaller than the curvature (R _I ) (R _R <R _I ). However, both curvatures may be equal (R _R = R _I ). Further, the shape of the guide portion (12) is not limited to the arc shape shown in the drawing, but may be another shape.
In order to prevent poor lubrication at the central portion (P) in the axial direction of the inner ring raceway surface (3) which requires a better lubrication state, at least the central portion (P) can surely contact the guide portion (12). Good shape.

In the cage (6), after placing the ball (5) between the inner and outer races (1) and (2), the guide portion (12) is brought into contact with the shoulder portion (1a) of the inner race (1). , Is installed in the bearing by inserting the inner part and the outer ring (1) and (2) while expanding the comb part (11) to the outer diameter side. When the approximately central portion of the guide portion (12) reaches the approximately central portion of the inner ring raceway surface (3), the comb portion (11) is elastically displaced toward the inner diameter side and returns to the original state.
Therefore, the engaging force acts between the guide portion (12) and the inner ring raceway surface (3) against the force that pushes the retainer (6) to the right side in FIG. 1, whereby the retainer ( 6) The retainer is prevented.

Tightening margin of the inner ring shoulder (1a) and the guide portion (12) when the retainer (6) is assembled (outer diameter of the inner ring shoulder (φ
l) and the minimum inner diameter (φg) of the guide part: φl-φg)
Is appropriately set depending on the elasticity of the retainer (6), but does not need to be so large.
It suffices that the insertion work of (1) is not hindered and the retainer (6) is reliably prevented from coming off. In the retainer (6) for guiding the inner ring raceway as described above, it is desirable to reduce the tightening allowance at the time of assembly, and even if there is no tightening allowance, the problem that the retainer (6) pops out under low speed conditions does not occur.

The guide gap between the guide portion (12) of the cage (6) and the inner ring raceway surface (3) is preferably a plus gap (φh> φg) from the viewpoint of low torque, but especially Under operating conditions that require good lubricity, zero clearance (φh = φg) or slightly negative clearance (φh <φ
It may be g).

According to this embodiment, the cage (6) made of coplanar resin having self-lubricity functions as a lubricant supply source. That is, when the guide portion (12) and the inner ring raceway surface (3) come into contact with each other during rotation of the bearing, the lubricant powder of the COPNA resin is transferred from the retainer (6) to the inner ring raceway surface (3). This transfer coating is not indirectly supplied via the balls (5), but is directly supplied from the retainer (6) to the inner ring raceway surface (3).
The film is formed reliably and satisfactorily, and the ball (5) is also transferred and supplied, so that the lubrication state of the bearing can be significantly improved.

In addition, because of the characteristics of the above-mentioned coplanar resin, there is no concern about deterioration of the lubricant at high temperature or depletion, and due to its excellent wear resistance, excessive lubricating powder that does not form a transfer coating is less likely to be generated, and the generation of the lubricant is suppressed. It also has advantages such as less dust.

Needless to say, if a solid lubricant such as a PTFE coating is used in combination, the bearing characteristics (low torque and low dust generation) can be more completely and stably obtained from the initial stage.

Further, the guide portion (12) has an inner ring raceway surface (3).
The retainer (6) is prevented from coming off at the same time because the structure is locked to. Therefore, even when applied to an open type bearing without a shield plate, the retainer (6) does not fall off from the bearing during use, and a stable use state is secured.

FIG. 3A shows an embodiment in which the present invention is applied to an outer ring guide type. That is, the guide portion (12) is formed on the outer diameter surface of the comb portion (11), and the guide portion (12) is guided by the outer ring raceway surface (4). Various conditions such as the size and shape of each part are the same as those of the bearing shown in FIGS. 1 and 2. Further, in FIG. 6B, in order to improve the assemblability of the retainer (6), the guide portion (12) is provided with all the comb portions (11).
This is an embodiment in which it is formed only on the outer diameter surface of the comb portion (11) opposed to each other by 180 degrees, not on the outer diameter surface of.

4 and 5, the cage (6) is divided into two, and one of the partial bodies (6a) is used as an inner ring raceway surface guide having a guide portion (12a) on the inner diameter surface. The other partial body (6b) is used as an outer ring raceway surface guide in which a guide portion (12b) is provided on the outer diameter surface. FIG. 4 shows a cage (6) divided into two parts in the diametrical direction to form an inner ring raceway surface guiding partial body (6a) and an outer ring raceway surface guiding partial body (6b), and FIG. The inner ring raceway surface guide partial body (6a) is formed within a range of 240 ° (2/3 of the circumference), and the outer ring raceway surface guide partial body (6b) is formed of 120 ° (1/3 of the circumference). It is formed in the range.

With such a structure, both the inner ring raceway surface (3) and the outer ring raceway surface (4) simultaneously contact the inner ring side guide portion (12a) and the outer ring side guide portion (12b), and both are lubricated. Since the film is formed, a better lubrication state can be obtained. As shown in FIG. 5, if the partial body (6a) for guiding the inner ring raceway surface is formed in a wider area than the partial body (6b) for guiding the outer ring raceway surface, the contact between the inner ring raceway surface (3) and the guide portion (12a) Since the probability increases, it is suitable when an excessive load is applied by the inner ring raceway surface (3), such as when the bearing is used for supporting the horizontal axis.

The reason why the cage (6) is divided into two is not only because of its assemblability, but in the integrated type, the inner ring raceway surface (3) and the outer ring raceway surface (4) cannot be contact lubricated at the same time. Because. Even with such a divided structure, the rotational movement of the cage (6) is not hindered as long as it is used at a low speed.

The embodiment shown in FIGS. 6 to 8 is similar to the embodiment shown in FIGS. 4 and 5 in that the cage (6) is composed of two partial bodies (6c) and (6d). , Each partial body (6
c) (6d) is different in that each is a crown-shaped annular molded body.

As shown in FIG. 7, one partial body (6c)
Is composed of an annular ring portion (10c) and a comb portion (11c) which is integrally formed with the ring portion (10c) and holds the ball (5) at a distance. The outer diameter surface of the comb portion (11c) is And a guide portion (12c) which is guided by contacting with the outer ring raceway surface (4).
The other partial body (6d) is composed of an annular ring portion (10d) and a comb portion (11d) which is integrally formed with the ring portion (10d) and holds the ball (5) at a distance. On the inner diameter surface of (11d), a guide portion (12) that is guided in contact with the inner ring raceway surface (3).
d). In this embodiment, the comb (11
c) and (11d) are formed at three positions that are equally distributed around the circumference.

As shown in FIG. 8, the retainer (6) of this embodiment has the above-described two partial bodies (6c) and (6d).
The comb parts (11c) and (11d) are axially abutted with their phases shifted from each other. Six pockets for accommodating the ball (5) are formed between the three comb parts (11c) of the partial body (6c) and the three comb parts (11d) of the partial body (6d).

As shown in FIG. 6, the guide portion (12c) of the partial body (6c) contacts the outer ring raceway surface (4), and the guide portion (12d) of the partial body (6d) contacts the inner ring raceway surface (3). By contacting with, the transfer coating is formed on both the inner ring raceway surface (3) and the outer ring raceway surface (4), so that a good lubrication state is obtained. Moreover, since each of the partial bodies (6c) and (6d) is a ring body, the rigidity is relatively high as compared with the divided structure shown in FIGS. If the annular parts (10c) and (10d) of the partial bodies (6c) and (6d) are extended in the inner and outer radial directions, a function as a shield plate can be imparted.

In the above description, the cage (6) is made of Kopuna resin, but the cage (6) may be made of other materials as long as it has self-lubricating property. Further, although the shape of the cage (6) is a crown type (comb type), it is not limited to this shape, and if the cage (6) having another shape can be used, it can be used. Good.

[0043]

According to the present invention, the transfer coating on the raceway surface is
It will be supplied directly from the cage, not via the rolling elements. Therefore, the coating on the raceway surface is surely and satisfactorily formed, and the lubrication state of the bearing can be significantly improved. Further, since the guide portion is locked to the raceway surface, the retainer can be prevented from coming off at the same time, which can be stably used for a long period of time and can be easily applied to the open type bearing.

By constructing the cage by the partial body including the inner ring side guide portion which is contact-guided to the inner ring raceway surface and the partial body including the outer ring side guide portion which is contact-guided to the outer ring raceway surface,
Since both the inner ring raceway surface and the outer ring raceway surface are in contact with the guide portion at the same time and the lubricating coating is formed on both of them, a better lubrication state can be obtained.

By making the surface curvature of the guide portion smaller than that of the raceway surface, it is possible to surely form the lubricating coating on the axially intermediate portion of the raceway surface, which is a particularly severe lubrication condition.

If the cage is made of coplanar resin, the characteristics of the coplanar resin prevent the lubricant from deteriorating at high temperature and depleting the lubricant, and its excellent wear resistance enables low dust generation. It is convenient to use in high temperature and clean environment such as equipment.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a solid lubrication rolling bearing (inner ring raceway guide) according to the present invention, in which (a) is an axial cross section passing through a comb portion of a cage, and (b) is a center of a ball. An axial cross section is shown.

FIG. 2 is a perspective view of a cage used in the bearing.

FIG. 3 is a cross-sectional view of a solid lubrication rolling bearing (outer ring raceway surface guide) according to the present invention and a perspective view of a cage used in the bearing.

FIG. 4 is a sectional view showing an embodiment in which a cage is divided.

FIG. 5 is a sectional view showing an embodiment in which a cage is divided.

6A and 6B are a longitudinal sectional view (FIG. A) and a transverse sectional view (FIG. B) showing an embodiment in which a cage is composed of two annular partial bodies.

FIG. 7 is a front view showing each partial body in FIG.

FIG. 8 is a side view of the cage in FIG.

[Explanation of symbols]

 1 inner ring 2 outer ring 3 inner ring raceway surface 4 outer ring raceway surface 5 rolling element (ball) 6 cage 6a partial body (inner ring raceway surface guide) 6b partial body (outer ring raceway surface guide) 6c partial body (outer ring raceway surface guide) 6d part Body (inner ring raceway guide) 12 Guide part 12a Inner ring side guide part 12b Outer ring side guide part 12c Outer ring side guide part 12d Inner ring side guide part

Claims (4)

[Claims] 1. An inner ring and an outer ring, a plurality of rolling elements interposed between raceways of the inner and outer rings, and a self-lubricating material,
A solid lubrication rolling bearing including a cage for holding rolling elements at predetermined intervals, wherein the cage has a guide portion that is guided by contact with the raceway surface of the inner ring or the raceway surface of the outer ring. Lubricated rolling bearing. 2. An inner ring and an outer ring, a plurality of rolling elements interposed between raceways of the inner and outer rings, and a self-lubricating material,
A solid lubrication rolling bearing comprising a cage for holding rolling elements at a predetermined interval, wherein the cage includes a partial body including an inner ring side guide portion that is guided in contact with an inner ring raceway surface, and an outer ring raceway surface. And a partial body including an outer ring side guide portion that is guided in contact with the solid lubrication rolling bearing. 3. The solid lubricated rolling bearing according to claim 1, wherein the guide portion has an arcuate cross section, and the surface curvature thereof is smaller than the curvature of the raceway surface. 4. The solid lubrication rolling bearing according to claim 1, 2 or 3, wherein the cage is made of a Kopuna resin.