JP2009168046A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing capable of being securely fastened, in particular, to a shaft hole having a groove for air vent or a keyway, further a rolling bearing capable of preventing creeping even in the rolling bearing for an alternator used under severe condition by enabling an outer ring of a rolling bearing to be surely fixed in the shaft hole. <P>SOLUTION: In the rolling bearing, one or more circumferential grooves 5 are formed on the outer peripheral surface of an outer ring 4 of the rolling bearing, and a resin band 6 consisting of thermosetting resin in an undercured state is fitted into the circumferential groove 5 so as to project radially outward from the outer peripheral surface of the outer ring 4. The resin band 6 may be integrally formed with the outer ring 4 by filling unset resin into the circumferential groove 5. The resin band is exposed to heat history to be hardened, and integrally engaged with the groove for air vent or the keyway so that the function for creep prevention is fulfilled securely. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rolling bearing that is fixed with a preload when fitted in a shaft hole.

In general, a rolling bearing that is fitted in a shaft hole of a housing or the like and fixed with a preload secures a “squeeze (tightening margin)” of the bearing outer ring even under high temperature conditions, and a thermal expansion difference from the shaft hole forming member In consideration of the need to prevent so-called “creep”, a resin band is integrally provided on the outer diameter surface of the outer ring so as to prevent the reduction of the support force and the “shift” in the rotation direction.
The resin band is provided in an endless annular shape extending in the circumferential direction on the outer peripheral surface of the outer ring, and is provided integrally with the outer ring in a state where the bottom portion is fitted in the circumferential groove.

  A resin band having a function of correcting an error of “tightening” due to thermal expansion is particularly called an expansion compensation bearing (or EC bearing (Expansion Compensating Bearing)).

  The material of the resin band attached to the rolling bearing is often formed of polyamide 66 (abbreviated as PA66) having a relatively large linear expansion coefficient (Patent Document 1).

  The predetermined height protruding on the outer periphery of the outer ring of the resin band comprehensively considers the expansion amount when the outer ring is heated from room temperature to high temperature, the expansion amount of the housing, and the expansion amount of the resin band. The resin is set by adjusting the material, volume, and shape of the resin so that an “interference” can be obtained with an appropriate thickness at both normal and high temperatures.

  As a rolling bearing that particularly demands such a requirement, there is a rolling bearing for an alternator that is used in severe temperature conditions and other usage conditions.

As shown in FIG. 3, in the automotive alternator, a rotor rotating shaft 13 on which a rotor 12 is mounted is rotatably supported by a pair of ball bearings A in a housing. A rotor coil 15 is attached to the rotor 12, and a three-turn stator coil 17 is attached to the stator 16 disposed on the outer periphery of the rotor 12 with a phase of 120 °.
Such an alternator for an automobile is an AC generator capable of generating electric power by receiving rotation of an automobile engine by a belt (not shown), supplying electric power to an electric load of the vehicle, and charging a battery.

  The rotor rotating shaft 13 is rotationally driven by the rotational torque from the automobile engine transmitted to the pulley 20 attached to the tip of the rotor 20 by a belt (not shown). A current is induced, full-wave rectified by the rectifier 21, and the battery is charged.

  Since the pulley 20 is attached to the rotor rotating shaft 13 in a cantilever state, and vibration is also generated with high-speed rotation, the ball bearing A that supports the pulley 20 side receives particularly severe load. In FIG. 3, reference numeral 18 denotes a step ring, and 19 denotes a fan.

  Since the ball bearing A rotates at a high speed of 10,000 rpm or more in an atmosphere in a heated engine room, it may become a high temperature of 180 ° C. or higher. Such bearings are required to have heat resistance and low rotational torque for suppressing temperature rise, and also have durability.

JP 09-314695 A

  However, in the conventional rolling bearing described above, it is not easy to obtain a sufficient fixing force with respect to the shaft hole, and the resin band is thermally deformed by the temperature rise of the bearing, and particularly in the alternator, the housing is formed of an aluminum alloy. Therefore, there is a problem in that it is difficult to prevent sufficient creep prevention due to a decrease in “interference” due to thermal expansion at a high temperature.

  Also, when attaching a rolling bearing to the shaft hole, the shaft hole may be provided with an air vent groove to release compressed air that tends to accumulate at the tip in the press-fitting direction, and a key groove is formed. A rolling bearing with a resin band may be fitted into the shaft hole.

  However, when an outer ring with a resin band of a rolling bearing is press-fitted into the shaft hole in which these grooves are formed, no tightening force is generated on the outer ring at the grooved portion, so that the rolling bearing is sufficiently prevented from creeping. I ca n’t do it.

  Accordingly, the object of the present invention is to solve the above-described problems so that the outer ring of the rolling bearing can be securely fixed to the shaft hole, and in particular, an air vent groove and a key groove are formed. In other words, the rolling bearing can be securely fixed to the shaft hole, and the rolling bearing can be sufficiently prevented from creeping as a rolling bearing for an alternator having severe use conditions.

  In order to solve the above-mentioned problems, in the present invention, one or more circumferential grooves are formed on the outer peripheral surface of the outer ring of the rolling bearing, and the under-cured heat is projected so as to protrude radially outward from the outer peripheral surface of the outer ring. This is a rolling bearing provided with a resin band made of a curable resin fitted in the circumferential groove. The resin band may be formed by filling the circumferential groove with an uncured resin and integrally molding the outer ring.

  The rolling bearing of the present invention configured as described above is an under cure when a shaft hole in which one or more air vent grooves or key grooves are formed, or when there is a groove or other recess in the shaft hole for any purpose. A part of the fixing resin band made of the thermosetting resin in the state enters the groove or the recess by deformation due to elastic deformation or the like.

  The resin band made of under-cured thermosetting resin receives a heat history by positively baking after use, or by the amount of heat generated in the bearing during use or the amount of heat received from the external environment during use. Then, the reaction of the remaining curing agent and residual monomer proceeds, and the crosslinking density increases.

In this way, the resin band naturally cooled after the crosslinking density is increased by heating or the like becomes harder than before due to receiving the thermal history, and engages with the groove or key groove for air venting and the outer ring and its supporting surface. Integrates and demonstrates a reliable anti-creep function.
That is, in the resin band that has been cured due to a thermal history during use or the like, the portion that has entered the groove is cured to form a so-called “anti-rotation structure such as a key structure”, thereby improving creep prevention.

  In order to form the resin band, it is preferable to inject uncured resin into the circumferential groove of the outer ring of the rolling bearing and to form it integrally with the outer ring in order to improve the adhesion with the rolling bearing and to make it integral. In addition, it is preferable for increasing the production efficiency.

In order to attach the rolling bearing to the shaft hole, it is only necessary to press-fit in the axial direction while pressing the outer peripheral surface of the outer ring and fix it with a preload, and it is the same as a rolling bearing for normal press-fitting.
A rolling bearing for fixing a grooved shaft hole in which an outer ring is fitted and fixed in a shaft hole in which a groove for air venting or a key groove is formed is composed of such a rolling bearing. As a rolling bearing for an alternator, it exhibits sufficient anti-creep properties.

  If the resin band is a resin band made of a phenol resin, it can be cured to a sufficient hardness of 124 to 128 on the Rockwell hardness M scale, for example, without adding a filler. It is surely integrated with the groove and has an anti-creep effect.

  Since this invention is a rolling bearing provided in a state in which a fixing resin band made of an undercured thermosetting resin is fitted to a circumferential groove formed on the outer peripheral surface of the outer ring of the rolling bearing, a groove for removing air or It is possible to securely fix the outer ring of the rolling bearing to the shaft hole in which a lockable recess such as a keyway is formed, and it has sufficient anti-creep properties, especially as a rolling bearing for alternators with severe use conditions. There is an advantage that can be exhibited.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIGS. 1 and 2, the embodiment is a rolling bearing in which an air vent groove 3 is formed in the shaft hole 2 of the housing 1, and the shaft hole 2 is press-fitted and fixed in the axial direction. One or more circumferential grooves 5 are formed on the outer peripheral surface of the outer ring 4 at intervals in the axial direction, and a grooved shaft hole in which a resin strip 6 made of an undercured thermosetting resin is fitted in the circumferential groove 5 This is a fixed rolling bearing. In the figure, reference numeral 7 denotes a spherical rolling element, reference numeral 8 denotes an inner ring, reference numeral 9 denotes a cage, and reference numeral 10 denotes a seal member.

  The air vent groove 3 formed in the shaft hole 2 is not particularly limited in view of the cross-sectional shape, but is a circular (or elliptical) groove shape, polygonal groove shape, V groove shape, stepped groove, bottom portion. It may be a well-known groove shape such as a groove having a protruding line on the inside.

  Although two circumferential grooves 5 are formed on the outer peripheral surface of the outer ring 4 with an interval in the axial direction, the arrangement and the number of the peripheral grooves 5 can be set as appropriate. One groove is an edge of the outer peripheral surface. It may be provided in the central portion or the central portion, and three or more grooves may be arranged at an appropriate interval.

  In order to provide the resin band 6 in a state of being fitted to the circumferential groove 5, the resin band 6 may be molded into a ring shape and then fitted into the circumferential groove 5, but provided separately so as to cover the circumferential groove 5 of the outer ring 4. Alternatively, the resin band 6 may be composite-molded on the outer ring 4 by a molding method in which an uncured resin as a molding material is injected from a gate provided on the mold.

  The thermosetting resin used in the present invention is not particularly limited to a specific resin type as long as the required elasticity can be obtained in an undercure state, for example, phenol resin, epoxy resin, melamine resin, urea resin, Silicon resin, polyester resin, diallyl phthalate resin, etc. can be employed.

  In order to make a fixing resin band made of a thermosetting resin in the required undercured state of elasticity, when performing a normal curing process of crosslinking a so-called thermosetting resin by the action of heat, light, radiation, catalyst, etc. The molding temperature can be lowered by about 5 to 30 ° C. than usual, or the molding time or curing time can be shortened by about 5 to 30 minutes. As will be described later, for example, a phenol resin may be heated at 150 ° C. for about 1 minute.

The degree of the undercure state is not particularly limited, and the thermosetting resin may be elastically deformed into the groove when the outer peripheral surface of the outer ring is pressed against the shaft hole in the axial direction. What is necessary is just to be able to cure | harden secondarily by secondary heating etc. after that.
The amount of heat required for the secondary heating for complete curing (curing) may be performed before use by heating the entire rolling bearing gradually or quickly in the usage state of the rolling bearing, Preferably, the glass transition temperature is heated to around Tg. For example, by heating to about 30 ° C. lower than Tg, the reaction of the remaining unreacted groups such as residual curing agent and residual monomer proceeds and the crosslinking density increases, so that the hardness and elastic modulus are higher than those immediately after the initial curing. The glass transition temperature also increases.
Specifically, a method similar to so-called after baking can be taken, and as an example of aggressive heat treatment conditions, heating is performed at 120 to 150 ° C. for several hours to several tens of hours (usually within 48 hours). Is preferred. "

  A mold provided separately to cover the circumferential groove formed on the outer peripheral surface of the outer ring of the rolling bearing is covered, and a phenolic resin as a molding material is injected into the mold from the gate and heated at 150 ° C. for 1 minute. The outer ring was provided with a deep groove ball bearing (see FIGS. 1 and 2) in which an under-cured resin band was compositely molded.

  As shown in FIG. 3, the obtained rolling bearing is incorporated into an alternator of an automobile, and at that time, the outer peripheral surface of the outer ring is press-fitted into the shaft hole and fixed in the axial direction and fixed with preload. Assuming the state of use, the condition that the entire rolling bearing was heated to 160 ° C. was maintained for 30 hours, and then allowed to cool to room temperature.

  When the obtained rolling bearing was forcibly removed from the alternator and examined, the part that entered the groove was hardened to form a so-called `` rotation structure like a key structure '', and the creep prevention property was improved. It was confirmed that

Sectional drawing of the axial direction which expands and shows the principal part of embodiment II-II sectional view of FIG. Sectional view of an alternator for explaining the state of use of the embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2 Shaft hole 3 Groove 4 Outer ring 5 Circumferential groove 6 Resin band 7 Rolling body 8 Inner ring 9 Cage 10 Seal member 12 Rotor 13 Rotor rotating shaft 15 Rotor coil 16 Stator 17 Stator coil 18 Step ring 19 Fan 20 Pulley 21 Rectifier

Claims (6)

  One or more circumferential grooves are formed on the outer circumferential surface of the outer ring of the rolling bearing, and a resin band made of an under-cured thermosetting resin is fitted into the circumferential groove so as to protrude radially outward from the outer circumferential surface of the outer ring. A rolling bearing characterized by being provided in a state.   The rolling bearing according to claim 1, wherein the resin band is formed by filling a circumferential groove with an uncured resin and integrally molding the outer ring.   A rolling bearing for press-fitting and fixing, comprising the rolling bearing according to claim 1, wherein the outer peripheral surface of the outer ring is press-fitted into a shaft hole and fixed with a preload.   A rolling bearing for fixing a grooved shaft hole, comprising the rolling bearing according to any one of claims 1 to 3, wherein an outer ring is fitted and fixed in a shaft hole in which an air vent groove or a key groove is formed.   The rolling bearing according to claim 4, wherein the rolling bearing is a rolling bearing that supports a rotating shaft of an alternator.   The rolling bearing according to claim 4, wherein the resin band is a resin band made of a phenol resin.

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