JP2003056571A - Plastic holder for roller bearing and roller bearing having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic holder for a roller bearing, durable without being damaged under disadvantageous operated conditions, having both-side side rings 1, 2 spaced from each other in the axial direction and a plurality of cross pieces 3 extending in the axial direction for joining the both-side side rings 1, 2 with each other, the cross pieces 3 which are distributed over the circumference of the side rings 1, 2 to form pockets 4 storing rollers 5 together with the both-side side rings 1, 2, the both-side side rings 1, 2 having different diameters, so that the plastic holder can be manufactured by using a tool mov able to the axial direction during injection molding. SOLUTION: Each of the cross pieces 3 has a first guide surface 6, protruding to the outside in the radial direction, so that the holder can be guided on the flange 18 which is protruded outside from the both-side side rings 1, 2 in the radial direction, provided on the outer ring 17 of the rolling bearing and turned to the inside in the radial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic cage for rolling bearings, which is formed so as to be manufactured by injection molding, and a rolling bearing including the cage.

[0002]

2. Description of the Prior Art Such cages are already known from German Utility Model Registration No. 1886747. This known cage has a plurality of crosspieces forming pockets for accommodating rolling elements, the crosspieces being connected to each other at both ends by side wheels. The radial dimension of the side ring of this cage is half the radial dimension of the crosspiece. One side wheel extends from the cage inner diameter to the center of the cross piece cross section, and the opposite side wheel extends from the center of the cross piece cross section to the cage outer diameter. The known cage is designed for particularly easy assembly.

However, in addition to assembly problems, plastic cages have proved to be problematic with respect to their durability, especially under adverse operating conditions.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a plastic cage which is durable and will not be damaged even under adverse operating conditions.

[0005]

Means for Solving the Problems and Effects of the Invention The objects of the present invention are solved by the means as set forth in claim 1.

The plastic cage according to the invention is
It has both side wheels axially spaced from each other. The two side wheels are connected to each other by a plurality of axially extending cross pieces. These cross pieces are distributed along the circumference of the side wheels so as to form pockets for accommodating the rolling elements together with the side wheels. The two side wheels have different diameters so that the plastic cage can be produced with axially displaceable tools during injection molding. Each of the cross pieces projects radially outward from both side wheels and has a radially outward first guide surface for guiding the cage by radially inward flanges provided on the outer ring of the rolling bearing. Have

The plastic cage according to the invention is
Since there is no need for a tool that moves in the radial direction when forming by injection molding, it has the advantage of being inexpensive to manufacture.

Another advantage of the present invention is that the crosspiece has a large radial dimension that extends beyond the side wheels.
It is mechanically very strong. The free space formed by the radial protrusion of the crosspiece from the side wheels or the reduction of the cross section of the side wheels has the advantage that the lubricant can be transported very well in the axial direction.

In a preferred embodiment of the plastic cage according to the invention, the crosspieces are arranged on opposite sides of adjacent crosspieces for the auxiliary guidance of the plastic cage by the rolling elements. It has a second guide surface. The resulting composite guide provides the plastic cage according to the invention with great mechanical strength and resistance to radial vibrations.

The second guide surface is preferably formed such that the rolling element rolls in contact with the second guide surface on the outer side in the radial direction of the circle connecting the rolling element centers. This advantageously
The crosspiece can be very thick and therefore mechanically strong.

Planar depressions are provided on the mutually facing surfaces of the adjacent cross pieces. Fouling particles accumulate therein, which keep them away from the first and second guide surfaces in particular. This prevents the formation of grooves on the outer peripheral surface of the rolling element.
The recess is up to 0.3 mm so that the plastic cage manufactured by injection molding can be demolded without problems.
Have a depth of.

Further, on the surfaces of the adjacent cross pieces facing each other, a projection arranged at the center in the axial direction is provided in order to prevent the rolling elements from falling off. The central arrangement of the projections makes it possible to maintain a free space in the axial direction between the projections and the side wheels and thus increase the flexibility of the plastic cage.

The crosspiece is provided with recesses in the first guide surface in order to reduce the mass of the plastic cage according to the invention and to optimize the injection of the injection molding material during the production of the cage. .

The transition areas between each side wheel and the crosspiece are each rounded to reduce stress.

The surfaces of the two side wheels that face each other in the axial direction are curved in a convex shape in the range between the adjacent cross pieces in order to reduce the wear of the rolling elements that roll in contact with them.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings.

For the sake of clarity, FIGS. 1, 2 and 3 only show a part of the plastic cages that project radially at regular intervals in the circumferential direction. As can be seen from these figures, the plastic cage has two side wheels 1, 2 axially spaced from each other. The both side wheels 1, 2 are connected to each other by a plurality of axially extending crosspieces 3. These cross pieces 3 are distributed over the circumferences of the side wheels 1 and 2 so as to form pockets 4 for accommodating the rolling elements 5 together with the side wheels 1 and 2. The two side wheels 1, 2 have different diameters so that the plastic cage can be manufactured with axially displaceable tools during injection molding. In other words, the inner diameter of the one side wheel 1 is set to be larger than the outer diameter of the opposite side wheel 2 so that the both side wheels 1 and 2 do not overlap with each other when viewed in the axial direction.

Each of the plurality of cross pieces 3 has a first guide surface 6 protruding radially outward from both side wheels 1 and 2 and directed radially outward for guiding the cage by the bearing races. ing. Side wheels 1 and 2 on both sides of the cross piece 3
The radial wall surface between the first guide surface 6 and the outer diameters of the both side wheels 1 and 2 formed by the protrusion from allows the lubricant to flow favorably in the axial direction. In this context, when dimensioning the plastic cage, in order to ensure a sufficient flow of the lubricant, the projecting dimension of the crosspiece 3 from the side wheels 1, 2 is preferably at least 2 mm.

The crosspieces 3 adjacent to each other have, on their surfaces facing each other in the circumferential direction, second guide surfaces 7 for auxiliary guiding of the plastic cage by the rolling elements 5. The second guide surface 7 is formed such that the rolling element 5 rolls in contact with the second guide surface 7 on the outer side in the radial direction of the circle 9 connecting the plurality of rolling element centers 8. Therefore,
In the illustrated embodiment, the first guide surface 6 and the second guide surface 6
The guide surface 7 is involved in providing complex guidance. The involvement of the second guide surface 7 is optional and can be omitted,
This serves to stabilize the overall.

A planar recess 10 is further formed on the surface of the cross piece 3 on which the second guide surface 7 is present. Dirt particles are deposited in the recess 10. As a result, the dirt particles do not reach the second guide surface 7 and thus the first guide surface 6, so that the dirt particles cause the first and second guide surfaces 6, 7 or their guidance. Damage or severe wear on the opposing surfaces in contact with surfaces 6 and 7 is avoided. In order to enable the die removal of the plastic cage after injection molding, the recess 10
Is formed very shallow, which results in only a slight undercut that can be overcome without damaging the plastic cage. It has been confirmed that the above-mentioned characteristics of the depression 10 are obtained when the depth thereof is 0.3 mm at the maximum.

On the opposite sides of the cross pieces 3 adjacent to each other, a protrusion 11 for preventing the rolling elements 5 from falling off is provided in the vicinity of the inner peripheral edge thereof. As a result, the movement of the rolling elements 5 inward in the radial direction is restricted, that is, the rolling elements are prevented from falling off, so that the assembly of the cage equipped with the rolling elements is facilitated. The projection 11 is preferably centrally located in the axial direction and does not extend completely to the side wheels 1 and 2 so that a gap 12 is present. This increases the flexibility of the plastic cage and makes the assembly easier than in the case where the protrusion 11 is firmly connected to the side wheels 1 and 2.

The crosspiece 3 has a radial recess 13 extending axially in the region of the first guide surface 6. The recess 13 is open towards at least one side of the crosspiece 3 in the axial direction in order to allow die-cutting in the axial direction.

The transition area 14 between each side wheel 1, 2 and the crosspiece 3 is rounded in order to reduce the stress concentration in this area.

The axially facing surfaces 15 of the two side wheels 1, 2 which limit the axial play of the rolling element 5 are curved in a convex shape in the range between the adjacent cross pieces 3. As a result, wear on the end surface of the rolling element 5 rolling in contact therewith is reduced.

The rolling element 5 rolls between the inner ring 16 and the outer ring 17. The outer ring 17 has flanges 18 on both sides in the axial direction, which are oriented inward in the radial direction. The first guide surface 6 of the cross piece 3 is brought into contact with the surface 19 of these flanges 18 facing inward in the radial direction and slides.

In the assembled state, the plastic cage is surrounded by a lubricant, especially grease. This grease is especially useful for the first guide surface 6 and the second guide surface 7,
It is applied to minimize wear in these areas.

[Brief description of drawings]

FIG. 1 is a partial perspective view of a plastic cage according to the present invention.

FIG. 2 is a partial sectional view of a plastic cage according to the present invention.

FIG. 3 is a partial perspective view of a plastic cage according to the present invention.

[Explanation of symbols]

1 side wheel 2 side wheels 3 cross pieces 4 pockets 5 rolling elements 6 First guideway 7 Second guideway 8 Rolling body center 9 yen 10 depressions 11 protrusions 12 gaps 13 recess 14 Transition range 15 Axial surface 16 inner ring 17 outer ring 18 flange

Claims (11)

[Claims] 1. A pair of side wheels 1 and 2 axially spaced from each other, and a plurality of axially extending crosspieces 3 connecting the side wheels 1 and 2 to each other. Are distributed over the circumference of the side wheels 1 and 2 so as to form a pocket 4 for accommodating the rolling element 5 together with the side wheels 1 and 2, and the side wheels 1 and 2 are made of a plastic cage. In a plastic cage for rolling bearings, which have different diameters, so that they can be produced with axially displaceable tools during injection molding, the crosspieces 3 have side wheels 1, 2 respectively. 2 has a radially outwardly directed first guide surface 6 for guiding the cage by a radially inwardly facing flange 18 provided on the outer ring 17 of the rolling bearing and protruding radially outwardly from Rolling shaft characterized by Acceptable plastic cage. 2. The plastic cage according to claim 1, wherein the cross piece 3 is projected from the side wheels 1 and 2 in the radial direction by at least 2 mm. 3. The cross piece 3 has second guide surfaces 7 arranged on the mutually facing surfaces of the adjacent cross pieces 3 for auxiliary guiding of the plastic cage by the rolling elements 5. The cage made of plastic according to any one of claims 1 to 3. 4. The second guide surface 7 is formed so that the rolling element 5 rolls in contact with the second guide surface 7 on the outer side in the radial direction of a circle 9 connecting the plurality of rolling element centers 8. The plastic cage according to claim 3. 5. The cross piece 3 is such that the mutually facing surfaces of the adjacent cross pieces 3 are flat recesses 10.
The plastic cage according to any one of claims 1 to 4, further comprising: 6. The plastic cage according to claim 5, wherein the recess 10 has a maximum depth of 0.3 mm. 7. The cross piece 3 is such that the mutually facing surfaces of the cross pieces 3 adjacent to each other have a projection 11 arranged at the center in the axial direction in order to prevent the rolling elements 5 from falling off. The plastic cage according to any one of claims 1 to 6. 8. The plastic cage according to claim 1, wherein the cross piece 3 has a recess 13 in the first guide surface 6. 9. The plastic according to claim 1, wherein the transition regions 14 between the side wheels 1 and 2 and the cross piece 3 are rounded. Made cage. 10. The surface 15 of each of the side wheels 1 and 2 facing each other in the axial direction is curved in a convex shape in a range between the adjacent cross pieces 3. The cage made of plastic according to any one of the above. 11. An inner ring 16, an outer ring 17, and both inner and outer wheels 1.
In a rolling bearing with rolling element 5 arranged between No. 6 and 17, rolling element 5 is arranged in the plastic cage according to any one of claims 1 to 10. Rolling bearing characterized by.