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CN-113669370-B - Retainer, bearing and speed reducer

CN113669370BCN 113669370 BCN113669370 BCN 113669370BCN-113669370-B

Abstract

The invention provides a retainer, a bearing and a speed reducer. A cage of the present invention is a cage (1) for holding a bearing (1A) of a plurality of rolling elements (2) about a central axis (F3), wherein the cage comprises a side peripheral portion (1A) that accommodates the plurality of rolling elements along the periphery of the central axis, annular plate-shaped end surface portions (1 b, 1 c) that are arranged radially from the end portions (1A 1, 1A 2) of the side peripheral portion in the direction of the central axis toward the direction based on the central axis, and reinforcing portions (1 d, 1 e) that are arranged on the end surface portions.

Inventors

  • Nagakata kunikazu

Assignees

  • 纳博特斯克有限公司

Dates

Publication Date
20260512
Application Date
20210413
Priority Date
20200513

Claims (6)

  1. 1. A cage for a needle roller bearing which holds a plurality of needle rollers having a cylindrical outer shape with an axis parallel to a central axis around the central axis, wherein, The retainer has: a side peripheral portion having a rectangular opening space for accommodating a plurality of needle rollers along a periphery of the central axis, the side peripheral portion forming a cylindrical surface around the central axis; A circular annular plate-shaped end surface portion arranged from both end portions of the side peripheral portion in a direction along the central axis toward a radial direction based on the central axis, and A regulating portion integrally formed with the end surface portion as a projecting strip opposed to each other at an entire circumference of a radial end portion of the end surface portion based on the central axis, and projecting toward a position closer to an end surface of the needle roller than a contour end surface of the side peripheral portion forming a contour of the opening space in a direction along the central axis, The end surface portions are each disposed radially outward of the side peripheral portion with respect to the central axis, the axis of the needle roller is located radially outward of the side peripheral portion with respect to the central axis, the restricting portion is located radially outward of the axis of the needle roller with respect to the central axis, The plurality of needle rollers are arranged so as to be equidistant from each other in the circumferential direction based on the central axis, The distance between the needle rollers adjacent in the circumferential direction based on the center axis at a position where the radial position based on the center axis is equal to a pitch circle including the axis of the needle rollers is smaller than the distance between the opening spaces adjacent in the circumferential direction based on the center axis at a position where the radial position based on the center axis is equal to the cylindrical surface of the side peripheral portion.
  2. 2. A cage for a needle roller bearing which holds a plurality of needle rollers having a cylindrical outer shape with an axis parallel to a central axis around the central axis, wherein, The retainer has: a side peripheral portion having a rectangular opening space for accommodating a plurality of needle rollers along a periphery of the central axis, the side peripheral portion forming a cylindrical surface around the central axis; A circular annular plate-shaped end surface portion arranged from both end portions of the side peripheral portion in a direction along the central axis toward a radial direction based on the central axis, and A regulating portion integrally formed with the end surface portion as a projecting strip opposed to each other at an entire circumference of a radial end portion of the end surface portion based on the central axis, and projecting toward a position closer to an end surface of the needle roller than a contour end surface of the side peripheral portion forming a contour of the opening space in a direction along the central axis, The end surface portion protrudes radially inward based on the central axis from both end portions of the side circumferential portion in a direction along the central axis, the axis of the needle roller is located radially inward based on the central axis than the side circumferential portion, the restricting portion is located radially inward based on the central axis than the axis of the needle roller, The diameter of the cylindrical surface formed by the side peripheral portion is larger than the pitch diameter of the needle roller arrangement, The plurality of needle rollers are arranged so as to be equidistant from each other in the circumferential direction based on the central axis, The distance between the needle rollers adjacent in the circumferential direction based on the center axis at a position where the radial position based on the center axis is equal to a pitch circle including the axis of the needle rollers is smaller than the distance between the opening spaces adjacent in the circumferential direction based on the center axis at a position where the radial position based on the center axis is equal to the cylindrical surface of the side peripheral portion.
  3. 3. The holder according to claim 1 or 2, wherein, The end face portion and the restriction portion are integrally formed by press working.
  4. 4. The holder according to claim 1 or 2, wherein, An end portion in a direction of the central axis toward a contour of the open space as viewed in a radial direction based on the central axis and an end portion in a direction of the central axis of the needle roller as seen from the open space are separated from each other.
  5. 5. A bearing, wherein, The bearing has: an outer ring formed in an annular shape and having an outer rolling surface facing radially inward; An inner ring disposed coaxially with the outer ring and having an inner rolling surface facing the radially outer side, a plurality of needle rollers rolling on the inner rolling surface and the outer rolling surface, and The cage of claim 1 or 2, which holds a plurality of said needle rollers.
  6. 6. A speed reducer, wherein, The speed reducer is provided with: An outer tube having inner teeth formed on an inner circumferential surface thereof and arranged in a circumferential direction; an eccentric oscillating gear having external teeth meshed with the internal teeth of the outer cylinder; a crankshaft connected to a driving source for oscillating the eccentric oscillating gear, and A carrier that supports the crankshaft and rotates relative to the outer tube, The crankshaft is supported by the carrier by the bearing according to claim 5.

Description

Retainer, bearing and speed reducer Technical Field The invention relates to a retainer, a bearing and a speed reducer. The present application claims priority based on japanese patent application publication No. 2020-084679, 5/13/2020, and this japanese patent application is incorporated herein by reference. Background For industrial robots, machine tools, and the like, a decelerator having a needle bearing is sometimes used. For the needle bearing, many rolling elements (needles) held to pockets (openings) of a cage are sandwiched by an inner ring and an outer ring to form the bearing. The plurality of pockets (openings) of the retainer are arranged in the circumferential direction with respect to the center axis of the bearing. The retainer has a pillar portion formed between adjacent pockets (openings). The reduction gear RV tends to increase the needle filling rate of the needle bearings used for the crank shaft portion as the output density increases. In particular, in the case of an eccentric oscillating type reduction gear, the tendency of the needle filling rate to increase is remarkable. Prior art literature Patent literature Patent document 1 Japanese patent application No. 2628674 Disclosure of Invention Problems to be solved by the invention However, if the needle filling rate increases, the pocket (opening) in which the needle is inserted in the holder increases. Therefore, the distance between adjacent pockets (openings) becomes smaller in the circumferential direction based on the central axis, and the circumferential dimension of the pillar portion becomes smaller. Thus, there is a case where the strength of the retainer is lowered. In a decelerator used for a robot or the like, a tilting force is generated in a needle roller of a needle bearing. There are cases where the needle roller tilts due to the oblique force. When the needle roller of the needle bearing is inclined, the needle roller collides with the contour of the pocket (opening) of the retainer in an inclined state. The needle rollers collide with the end face side of the contour of the pocket (opening) along the center axis and the column side in the circumferential direction of the center axis. Thereby, stress concentration occurs in the corner post root R portion of the outline of the pocket (opening) of the retainer. However, in the case of the retainer having a reduced strength, there is a problem that a portion located in the vicinity of the pocket of the retainer may be broken due to concentration of stress. The present invention provides a structure capable of improving the strength of a retainer for a needle bearing, and provides a retainer, a bearing, and a speed reducer capable of preventing the occurrence of breakage due to an oblique force with a simple structure. Solution for solving the problem The retainer according to an aspect of the present invention solves the above-described problems by: the cage is a cage of a bearing holding a plurality of rolling elements around a central axis, wherein, The retainer is provided with: a side peripheral portion that accommodates the plurality of rolling elements along a periphery of the central axis; A circular annular plate-shaped end surface portion arranged radially to the center axis at an end of the side peripheral portion, and And a reinforcing portion disposed on the end surface portion. According to the cage of the aspect of the present invention, when the rolling elements are inclined with respect to the center axis by the oblique force and come into contact with the side peripheral portion, the strength of the side peripheral portion is increased by the reinforcing portion, so that the cage can be prevented from being broken. The holder according to an aspect of the present invention can be configured such that, In the case of the above-mentioned holder, The reinforcement portion is formed in a circular ring shape. The holder according to an aspect of the present invention can be configured such that, In the case of the above-mentioned holder, The reinforcing portion is a thick portion formed integrally with the end face portion and having a thickness thicker than a thickness of the end face portion in a direction along the central axis. The holder according to an aspect of the present invention can be configured such that, In the case of the above-mentioned holder, The end portions of the reinforcing portion and the end portions of the rolling elements can be in contact with each other in a direction along the central axis. The holder according to an aspect of the present invention can be configured such that, In the case of the above-mentioned holder, The side peripheral portion is provided with the end face portions at both end portions in a direction along the central axis. The holder according to an aspect of the present invention can be configured such that, In the case of the above-mentioned holder, The reinforcing portion is formed on the opposite surface