JPH079251B2 - Solid lubricant retainer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Object of the Invention [Field of Industrial Application] The present invention relates to a solid lubrication technology for high temperature ceramic rolling bearings, and more particularly to a self-lubricating cage.

“Prior art” The main fields of application of ceramic rolling bearings are high-speed bearings that focus on the low density of ceramics, and high-temperature bearings that take advantage of the high temperature strength of ceramics.

When applying ceramics to high-temperature bearings, it can be said that the material properties will be utilized only when used in high-temperature regions where conventional bearing materials and lubricants are not used.

However, when ceramics are applied to rolling bearings, their lubrication poses a problem.

That is, conventional high temperature lubricating oil and grease cannot be used in the temperature range of 500 ° C or higher in the atmosphere. Therefore, solid lubricant is used for lubrication in this region. A method generally used as a solid lubrication method for this rolling bearing is a method by transfer of a solid lubricant. As shown in FIG. 9 and FIG. 10, this transfer method refers to a rolling bearing 21 composed of a bearing ring (inner ring 22, outer ring 22), a cage 24, and rolling elements (ball 25 or roller 26). , Bearing rings 22,23
And the rolling elements 25 and 26 are made of ceramics, and the cage 2
4 is composed of a solid lubricant. During rolling, the solid lubricant is transferred from the cage 24 to the surfaces of the rolling elements 25 and 26, and the races 22 and 23
It will be transferred to the orbital plane of. In this way, the solid lubricant is replenished to the rolling surface to continue the lubrication.

[Problems to be Solved by the Invention] However, the solid lubricant retainer has a relatively brittle property because the solid lubricant powder is molded and manufactured. On the other hand, the hoop stress (circumferential stress) acts on the cage of the bearing that rotates at high speed due to its centrifugal force, and for materials with low tensile strength (brittle material), when the rotational speed exceeds the limit, the cage has a cross section with low strength. Break.

Therefore, it has been considered to add a reinforcing material to a cage made of a solid lubricant to enhance the strength, but such a reinforcing method is not preferable because it complicates the structure of the cage and impairs lubrication characteristics.

The present invention has been made in view of the above circumstances, and the solid lubricant can be satisfactorily transferred even in a high temperature environment, and the operation of the bearing can be disabled even at a high speed without any reinforcement. 500 ℃ in the atmosphere without causing any damage
It is an object of the present invention to provide a ceramic rolling bearing which can be used in the above environment, has a simple structure, and has high lubricating characteristics.

(B) Structure of the Invention [Means for Solving the Problem] To this end, the solid lubricant retainer of the present invention comprises:
An annular retainer made of a solid lubricant for holding the rolling element in the pocket between the bearing rings, the ring having a plurality of the rolling element pockets, and the ring is circumferentially divided,
At least one of the inner peripheral surface and the outer peripheral surface of the retainer piece is made to have the same curvature as the opposing peripheral surface of the bearing ring. It is characterized by being formed.

Hereinafter, details of the present invention will be described with reference to the drawings illustrating an embodiment.

In FIGS. 1 and 2, 1a is a radial ball bearing, and the radial ball bearing 1a is held by an inner ring 1a, an inner ring 2 and an outer ring 3, a bearing ring, a retainer 4a, and a retainer 4a. It consists of rolling elements of balls 5.

The inner ring 2 and the outer ring 3 are made of silicon nitride (Si
_The raceway surface 7 made of ceramics such as ₃ N ₄ ) and on which the balls 5 roll may be covered with a metal coating. The metal coating is iron (F
e), a metal such as chromium (Cr) is deposited by sputtering, ion plating, vapor deposition or the like. The cage 4a has a main body made of ceramics such as silicon nitride (Si ₃ N ₄ ) and has a surface coated with a solid lubricant such as molybdenum disulfide, tungsten disulfide or graphite, or the cage 4a is entirely formed. Composed of fixed lubricant.

Particularly importantly, the cage 4a is located in a plane orthogonal to the central axis of the bearing, is circumferentially divided, and is an assembly of four cage pieces 10a each having a pocket for holding a rolling element. It is configured. The four retainer pieces 10a are located around the central axis of the bearing, and the whole retainer pieces are assembled to form an annular retainer 4a. In other words, the retainer pieces 10a divide the retainer 4a into four in the circumferential direction. It has a shape. The retainer piece 10a constitutes a retainer 4a for guiding the inner ring in the low speed rotation range and for guiding the outer ring in the high speed rotation range. Therefore, the inner peripheral surface 11 is formed to have the same curvature as the outer peripheral surface of the inner ring 2, Outer peripheral surface
12 is formed with the same curvature as the inner peripheral surface of the outer ring 3. The left and right side surfaces 13 and 14 of each cage piece 10a face or are in contact with both side surfaces of the adjacent cage pieces 10a.

FIG. 3 shows a retainer piece 10b constituting a retainer 4b for guiding the outer ring. The outer peripheral surface 12 of the retainer piece 10b has an outer ring 3 and an inner peripheral surface 2
It has the same curvature as 7.

The body of the ball 5 is made of ceramics such as silicon nitride (Si ₃ N ₄ ), and its surface is formed by sputtering metal such as iron (Fe) or chromium (Cr) by ion plating or vapor deposition. You may coat with the formed metal film.

[Operation] In the radial ball bearing configured as described above, in the low speed rotation range, as shown in FIGS. 1 and 2, the left and right side surfaces 13 and 14 of each cage piece 10a are adjacent to each other. Piece
An annular cage 4a is formed in contact with the side surface of 10a, and the balls 5 are held in a state in which the inner peripheral surface 11 is in contact with the outer peripheral surface of the inner ring 2, and the four cage pieces 10a as a whole are guided by the inner ring. Function as a retainer 4a.

When the radial ball bearing 1a is used in the high speed rotation range,
As shown in FIG. 4 and FIG. 5, hoop stress (circumferential stress) acts on the cage 4a due to centrifugal force, but each cage piece 10a is displaced to the outer ring guiding state, and Since the cage pieces 10a are separated from each other in the circumferential direction and are not restrained from each other, the hoop stress disappears.

Next, also in the case of the outer ring guide retainer 4b shown in FIG. 3, in the high-speed rotation range, as shown in FIG.
Since b shifts outward and each is separated in the circumferential direction,
No hoop stress is generated.

In addition, in order to improve the strength of the cage, it is important to increase the cross section parallel to the rotation axis of the cage. 7th
In the one shown in the figure, this cross section is enlarged by providing an annular protruding portion 16, but this protruding portion 16 engages with the outer ring 3 to function as an axial guide of the cage. The point that it is exerting is important. In the structure shown in FIG. 8, the cross section is enlarged by providing annular collars 17 at both ends, but the collar 17 also engages with the outer ring 3 to exert a function as an axial guide.

(C) Effect of the Invention The cage of the present invention is divided in the circumferential direction to form four cage pieces, and the four cage pieces are assembled to form a cage. Therefore, since the cage does not form an integral ring, hoop stress does not occur.

As described above, according to the present invention, by applying the damage mode of the cage at a high speed, and preliminarily dividing the cage in the circumferential direction, a reinforcing material harmful to the lubricating fiber is required. Without, the destruction of the cage can be avoided.

Although the above description relates to the embodiment in which the present invention is mainly applied to the radial rolling bearing, the present invention can be applied to the thrust bearing as it is.

[Brief description of drawings]

FIG. 1 is a front view of a radial bearing according to the first embodiment,
2 is a sectional view taken along the line II-II in FIG. 1, and FIG.
FIG. 4 is a front view of a radial bearing according to the embodiment of FIG.
FIG. 5 is a front view showing a state in the high speed rotation range of the radial bearing according to the embodiment, FIG. 5 is a sectional view taken along line VV in FIG. 4, and FIG. 6 is a high speed rotation range of the radial bearing according to the second embodiment. FIG. 7 is a sectional view of a cage, FIG. 8 is a sectional view of another cage, FIG. 9 is a sectional explanatory view showing a conventional radial ball bearing, and FIG. FIG. 3 is a cross-sectional explanatory view showing the radial roller bearing of FIG. 1a ... Radial ball bearing, 2 ... inner ring, 3 ... outer ring, 4a ...
… Cage, 5 …… ball, 7 …… orbit, 10a …… Cage piece, 1
1 …… Inner circumferential surface, 12 …… Outer circumferential surface, 13 …… Left side surface, 14 …… Right side surface, 16 …… Projecting portion, 17 …… Brim, 21 …… Rolling bearing,
22 …… Inner ring, 23 …… Outer ring, 24 …… Cage, 25 …… Ball, 26
...... Coro

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Tsutomu Yune, Inoue Nishinocho, Minami-ku, Osaka City, Osaka Prefecture, Kono Seiko Co., Ltd. (72) Hiroaki Takebayashi, Nishinocho, Nishinomachi, Osaka, Osaka Address: Koyo Seiko Co., Ltd., Judging body for referees Shinichiro Suzuki Judge Tadayoshi Ueno Judge Toshihiko Nishimura (56) References JP60-146917 (JP, A) JP60-241516 (JP, A) Japanese Unexamined Patent Publication No. 54-64244 (JP, A) Actual development No. 54-15145 (JP, U)

Claims (1)

[Claims] 1. An annular cage made of a solid lubricant for holding a rolling element in a pocket between races, each of which has a plurality of said rolling element pockets, and the ring is divided in the circumferential direction, Are assembled into a plurality of cage pieces that form the annular cage, and at least one of the inner peripheral surface and the outer peripheral surface of the cage piece is formed to have the same curvature as the opposing peripheral surfaces of the bearing ring. Solid lubricant retainer characterized in that