JP2002339981A - Single row ball turning bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single row ball turning bearing capable of smoothly turning a turntable under a partial load. SOLUTION: By cutting a holder 6 for holding balls in the circumferential direction between raceway surfaces of inner and outer rings in at least one part in the circumferential direction, any advancement/delay of the balls can be absorbed at a cut part of the holder even when any relative advancement/ delay phenomenon occurs due to the moment load so that no tensile or compressive load is applied to the holder 6, a bearing is rotated smoothly, and the holder is not broken either. In addition, by setting the thickness of the holder 6 >=1/2 of the dimension of a space between the inner and outer rings, the cut part of the holder 6 is prevented from overlapping in the space between the inner and outer rings, and any locked condition caused by the overlapping of the holder is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-row ball slewing bearing for rotatably supporting a turntable.

[0002]

2. Description of the Related Art A slewing bearing for rotatably supporting a turntable used for various machines such as a construction machine, a cargo handling machine, a machine tool, and various devices such as a parabolic antenna and a rotating stage is a ball bearing type, a roller. There are various types such as a bearing type and a cross roller type. This slewing bearing
In addition to the axial load and the radial load, a moment load is also applied along with the eccentric load applied to the turntable.

As shown in FIG. 4, each of the raceway surfaces 3 and 4 of the inner ring 1 and the outer ring 2 is formed by two curved surfaces, respectively.
A single-row ball slewing bearing that holds a plurality of single-row balls 5 between the raceway surfaces 3 and 4 with a retainer 6 and makes each ball 5 contact the raceway surfaces 3 and 4 at four points is a rolling element. Since the ball 5 is firmly held between the two raceway surfaces 3 and 4 and the rigidity of the inner and outer races 1 and 2 formed integrally with each other is high, a high load capacity can be obtained with a simple configuration.

In this single-row ball slewing bearing, a gear 9 meshing with the drive shaft of the turntable is provided on the inner periphery of the inner ring 1 so that the inner ring 1 rotates together with the turntable. In some cases, a gear is provided on the outer periphery of the outer ring, and the outer ring is rotated together with the turntable.

[0005] As shown in FIG. 5A, the retainer 6 is formed in a full circle, and a plurality of pockets for holding the balls 5 one by one as shown in FIG. 11
Is provided. Each pocket 11 is formed in a circular shape substantially equal to the diameter of the ball 5.

[0006]

In the single row ball slewing bearing, when the turntable turns while receiving an eccentric load,
The contact angle of each ball in contact with the raceway surface changes individually due to the moment load caused by the unbalanced load. As described above, when the contact angles of the balls individually change, the orbit diameters of the balls are different for each ball, and a relative advance / delay phenomenon occurs for the balls.

For this reason, in the conventional single-row ball slewing bearing described above, a tensile load or a compressive load acts on the cage for holding the ball, which hinders smooth rotation of the bearing and fluctuates in the slewing torque of the turntable. There is a problem that occurs. Further, the cage may be damaged due to repeated tensile load and compressive load.

An object of the present invention is to provide a single-row ball slewing bearing that can smoothly turn a turntable that receives an eccentric load.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to an inner ring and an outer ring in which each of the raceways is formed by two curved surfaces, and a plurality of balls in a single row are interposed between the raceways. Is held in a pocket of the cage in a circumferential direction, and when a load is applied, these balls are in four-point contact with the raceway surfaces of the inner and outer rings. And the thickness of the cage is set to a thickness equal to or more than １ ／ of the gap between the inner ring and the outer ring.

That is, by dividing the ball at least at one point in the circumferential direction between the raceway surfaces of the inner and outer rings, even if a relative advance / delay phenomenon of the ball due to a moment load occurs, the advance / delay of the ball is maintained. Since it can be absorbed by the divided part of the container, tensile load and compressive load do not act on the cage,
The bearing rotates smoothly and the cage is not damaged.

Also, in the present invention, the thickness of the cage is set to a thickness equal to or more than の of the gap between the inner ring and the outer ring. The divided portions of the retainer do not overlap each other, and the retainer and the inner and outer rings do not interfere with each other to be locked, so that the torque can be stabilized.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. This single row ball slewing bearing
As shown in FIG. 1, each of the raceways 3, 4 of the inner race 1 and the outer race 2 is formed by two curved surfaces, respectively.
A plurality of balls 5 in a single row are held by a retainer 6 therebetween, and each ball 5 comes into contact with each of the raceway surfaces 3 and 4 at four points. Grease is filled between the raceway surfaces 3 and 4 on which the balls 5 are held, and upper and lower ends thereof are respectively provided with sealing members 7.
Sealed by a and 7b.

The inner ring 1 is provided with a screw hole 8 for attaching a turntable, and a gear 9 which meshes with a drive shaft of the turntable is provided on the inner periphery thereof. The outer race 2 is provided with a bolt hole 10 for attachment to a fixed seat. Although not shown, the inner ring 1 has a ball 5
Is provided between the raceway surfaces 3 and 4, and this hole is closed with a stopper plug.

As shown in FIG. 2, the cage 6 is formed by equally dividing a ring-shaped one into six segments 6a in the circumferential direction. As shown in FIG. 2B, each segment 6a is provided with a pocket 11 for holding one ball 5 at a time.

The thickness T of the retainer 6 is set between the inner ring 1 and the outer ring 2.
The thickness is set to a half or more of the gap dimension H between them.

That is, when the plate thickness T of the retainer 6 is equal to or less than 1/2 of the clearance dimension H between the inner ring 1 and the outer ring 2, FIG.
As shown in (b), in the gap between the inner ring 1 and the outer ring 2, the ends of the segments 6a may overlap each other, interfere with the inner and outer rings, and may be in the worst locked state. By defining the plate thickness T of the retainer 6 as H / 2 <T <H, as shown in FIG. 3A, even if the ends of the segments 6a abut each other, they do not overlap. Therefore, friction between the inner and outer wheels and the retainer 6 can be suppressed, and the torque on the inner and outer wheels can be stabilized without interference.

[0017]

As described above, in the single-row ball slewing bearing of the present invention, the cage is divided at at least one position in the circumferential direction, so that the relative advance and delay of the ball due to the moment load occurs. However, since the advance / delay of the ball can be absorbed by the divided portion of the cage, a tensile load or a compressive load does not act on the cage, the bearing rotates smoothly, and the cage is not damaged.

Further, by setting the plate thickness of the retainer to be equal to or more than の of the gap size between the inner ring and the outer ring,
In the gap between the inner ring and the outer ring, since the divided parts of the cage do not overlap, the cage and the inner and outer rings interfere,
There is no possibility of the lock state, and the torque fluctuation can be suppressed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a single-row ball slewing bearing according to an embodiment of the present invention.

2A is a plan view of a retainer portion of FIG. 1, and FIG.

3A and 3B show the relationship between the gap size of the inner and outer races and the plate thickness of the cage according to the present invention, and FIG. 3A shows the case where the plate thickness of the cage is made equal to or more than 1/2 of the gap size of the inner and outer races. FIG. 4B is a plan view when the thickness of the cage is set to be equal to or less than half the clearance between the inner and outer rings.

FIG. 4 is a longitudinal sectional view showing a conventional single-row ball slewing bearing.

FIG. 5A is a plan view of a conventional cage, and FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3, 4 Raceway surface 5 Ball 6 Cage 6a Segment 7a, 7b Sealing member 8 Screw hole 9 Gear 10 Bolt hole 11 Pocket

Claims (2)

[Claims] An inner race and an outer race each have two raceway surfaces.
Formed of two curved surfaces, between which a plurality of balls in a single row are circumferentially held in pockets of the cage, and when a load is applied, these balls make four-point contact with the raceways of the inner and outer rings. In the single-row ball slewing bearing, the cage is divided at at least one location in the circumferential direction, and the thickness of the cage is set to be equal to or more than の of the gap between the inner ring and the outer ring. And single row ball slewing bearing. 2. The single-row ball slewing bearing according to claim 1, wherein the cage is divided into a plurality of segments.