JP2009008146A - Rolling bearing for piston pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the annular rigidity of an outer ring against a collision force of a piton without changing the dimension of a bearing. <P>SOLUTION: The annular rigidity of the outer ring 2 against an abutting force of the piston 12 can be enhanced without changing the bearing dimension by press-fitting a shield 5 as a reinforcement member which is a ring-like part 5a having an annular part 5a overhanging toward the inner diameter side into the inner diameter face of the outer ring 2 where the piston 12 abuts on the outer diameter face. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rolling bearing for a piston pump in which an inner ring is fitted on an eccentric shaft connected to an output shaft of a motor and a piston that reciprocates on an outer diameter surface of the outer ring is abutted.

  A rolling bearing for a piston pump in which an inner ring is externally fitted to an eccentric shaft connected to an output shaft of a motor, and a piston or plunger (hereinafter referred to as a piston) that reciprocates on the outer diameter surface of the outer ring is engaged with the outer ring of the outer ring. Due to the abutting force of the piston loaded at a single point on the radial surface, the annular outer ring is deformed so as to be flattened, and tensile stress is generated in the inner diameter part of the outer ring, which may damage the outer ring. In order to prevent such breakage of the outer ring, conventionally, a large-sized rolling bearing with a large rated load is used, or a plurality of single row ball bearings are arranged in contact with each other or close to each other (for example, , See Patent Document 1).

  On the other hand, rolling bearings for piston pumps used in piston pumps that supply brake fluid in reservoir tanks to the master cylinder in brake systems such as anti-lock brake systems (ABS) for automobiles are becoming more and more compact for automobile parts. A compact design is demanded in accordance with the demand for the realization. For this reason, as described above, the method of using a large-sized rolling bearing having a large rated load or disposing a double row single row ball bearing has a problem of hindering a compact design.

JP 2001-187915 A

  In order to prevent cracking of the outer ring due to the abutting force of the piston without increasing the size of the rolling bearing for the piston pump described above, the outer ring can be prevented from being flattened by the abutting force of the piston by increasing the thickness of the outer ring. Although it is conceivable to increase the annular rigidity, there is a problem that if the thickness of the outer ring is increased, the diameter of the rolling element has to be reduced, and the load capacity of the bearing is reduced.

  Accordingly, an object of the present invention is to increase the annular rigidity of the outer ring against the abutting force of the piston without changing the bearing dimensions.

  In order to solve the above problems, the present invention provides a rolling bearing for a piston pump in which an inner ring is fitted on an eccentric shaft connected to an output shaft of a motor, and a piston that reciprocates on an outer diameter surface of the outer ring is abutted. The configuration in which an annular reinforcing member is press-fitted into the inner diameter surface of the outer ring is adopted.

  That is, the annular rigidity of the outer ring against the abutting force of the piston can be increased without pressing the bearing dimensions by press-fitting an annular reinforcing member into the inner surface of the outer ring.

The longitudinal elastic modulus E of the reinforcing member is preferably equal to or greater than the longitudinal elastic modulus E of the outer ring. When the outer ring is formed of normal high carbon chrome bearing steel SUJ1-3 (E = 21000 kgf / mm ² ), the reinforcing member is medium carbon steel (E = 21000 kgf / mm) such as S45C in addition to these SUJ1-3. ² ), nickel-chromium steel (E = 22300 kgf / mm ² ) such as SNC 1 to 3 and the like.

  The radial thickness of the reinforcing member is preferably 1 mm or more. It is because sufficient annular rigidity cannot be secured if the radial thickness of the reinforcing member is less than 1 mm.

  By providing the reinforcing member with an annular portion that protrudes toward the inner diameter side, the annular rigidity of the outer ring can be further increased.

  The axial thickness of the annular portion is preferably 1 mm or more. This is because sufficient annular rigidity cannot be ensured when the axial thickness of the annular portion is less than 1 mm.

  The reinforcing member may be a shield that seals a bearing space between the inner ring and the outer ring.

  The reinforcing member may be a metal core to which another member is attached or a metal fitting that cooperates with the other member. The core metal to which other members are attached can be a member to which a seal member such as a rubber seal is attached, or a sensor to be detected such as a sensor or an encoder. The working metal fitting may be a slinger or the like to which the seal member is slidably contacted.

  In the rolling bearing for piston pump of the present invention, since the annular reinforcing member is press-fitted into the inner surface of the outer ring, the annular rigidity of the outer ring against the abutting force of the piston is increased without changing the bearing size, and the outer ring is less damaged. Can be prevented.

  By providing the reinforcing member with an annular portion that protrudes toward the inner diameter side, the annular rigidity of the outer ring can be further increased.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment. In this piston pump rolling bearing, an inner ring 1 externally fitted to an eccentric shaft 11a connected to an output shaft 11 that is rotationally driven by a motor (not shown) and a reciprocating piston 12 are abutted against an outer diameter surface. A ball bearing in which a plurality of balls 3 as rolling elements are held and arranged in a cage 4 between the outer ring 2 and the outer ring 2. A shield 5 as a reinforcing member provided with an annular portion 5b to be put out is press-fitted. The tip of the shield 5 is inserted into seal grooves 1 a provided at both ends of the outer diameter surface of the inner ring 1 so as to seal the bearing space between the inner ring 1 and the outer ring 2.

  The inner ring 1 and the outer ring 2 are made of high carbon chrome bearing steel SUJ2, and the shield 5 is made of medium carbon steel S45C having a longitudinal elastic modulus E equivalent to SUJ2. The radial thickness of the annular portion 5a of the shield 5 and the axial thickness of the annular portion 5b are set to 1 mm or more.

  FIG. 2 shows a second embodiment. The basic structure of this piston pump rolling bearing is the same as that of the first embodiment. The reinforcing member press-fitted into both end portions of the inner diameter surface of the outer ring 2 is vulcanized by the rubber seal 6 of the sealing member. The difference is that the metal core 7 is provided with an annular portion 7b attached to the annular portion 7a and projecting toward the inner diameter side. The tip of the rubber seal 6 is in contact with the seal groove 1 a on the outer diameter surface of the inner ring 1 to seal the bearing space between the inner ring 1 and the outer ring 2. Also in this embodiment, the metal core 7 is formed of S45C, and the radial thickness of the annular portion 7a and the axial thickness of the annular portion 7b are 1 mm or more.

  FIG. 3 shows a third embodiment. The basic structure of the piston pump rolling bearing is the same as that of the first embodiment. The reinforcing members press-fitted into both end portions of the inner diameter surface of the outer ring 2 are stretched to the inner diameter side of the annular portion 9a. The slinger 9 is provided with a ring portion 9b to be drawn out, and the seal member 8 mounted on the outer diameter surface of the inner ring 1 is in sliding contact with the ring portion 9b of the slinger 9. Also in this embodiment, the slinger 9 is formed of S45C, and the radial thickness of the annular portion 9a and the axial thickness of the annular portion 9b are 1 mm or more.

  In each of the above-described embodiments, the outer ring reinforcing member is a shield provided with an annular portion projecting to the inner diameter side on the annular portion, a core metal and a slinger of the sealing member, and these are formed of medium carbon steel S45C, Although the radial thickness of the part and the axial thickness of the annular part are 1 mm or more, only one of these thicknesses can be 1 mm or more, and the reinforcing member may have only an annular part. it can. Further, the reinforcing member can be formed of other medium carbon steel, high carbon chrome bearing steel, nickel chrome steel, or the like, and can also be a core bar to which various sensors and sensors to be detected are mounted.

  Furthermore, in each embodiment mentioned above, although the rolling bearing was made into the ball bearing, the rolling bearing for piston pumps concerning this invention is applicable also to other rolling bearings, such as a roller bearing.

The longitudinal cross-sectional view which shows the rolling bearing for piston pumps of 1st Embodiment The longitudinal cross-sectional view which shows the rolling bearing for piston pumps of 2nd Embodiment The longitudinal cross-sectional view which shows the rolling bearing for piston pumps of 3rd Embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner ring 1a Seal groove 2 Outer ring 3 Ball 4 Cage 5 Shield 5a Annular part 5b Annular part 6 Rubber seal 7 Core metal 7a Annular part 7b Annular part 8 Sealing member 9 Slinger 9a Annular part 9b Annular part 11 Output shaft 11a Eccentric Shaft 12 piston

Claims (7)

  In a rolling bearing for a piston pump in which an inner ring is fitted on an eccentric shaft connected to an output shaft of a motor and a piston that reciprocates on an outer diameter surface of the outer ring is abutted, an annular reinforcing member is provided on the inner diameter surface of the outer ring. Rolling bearing for piston pumps, characterized by being press-fitted.   The rolling bearing for a piston pump according to claim 1, wherein a longitudinal elastic coefficient of the reinforcing member is equal to or greater than a longitudinal elastic coefficient of the outer ring.   The rolling bearing for a piston pump according to claim 1 or 2, wherein the reinforcing member has a radial thickness of 1 mm or more.   The rolling bearing for a piston pump according to any one of claims 1 to 3, wherein the reinforcing member is provided with an annular portion projecting toward an inner diameter side.   The rolling bearing for a piston pump according to claim 4, wherein an axial thickness of the annular portion is 1 mm or more.   The rolling bearing for a piston pump according to any one of claims 1 to 5, wherein the reinforcing member is a shield that seals a bearing space between the inner ring and the outer ring.   The rolling bearing for a piston pump according to any one of claims 1 to 5, wherein the reinforcing member is a metal core to which another member is attached or a metal fitting that cooperates with the other member.

Images