JP3547223B2 - Ball bearing cage - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cage for a ball bearing.
[0002]
[Prior art]
The swivel bearing is used for various large-sized industrial machines, such as medical equipment such as a CT scanner rotating dome support bearing, construction equipment, and railway vehicles. Usually, since the diameter of the ball-shaft retainer constituting such a bearing for a swivel seat becomes large, a plurality of comb-shaped segment-type cages as shown in FIG. 4 are arranged in the circumferential direction. This is used as a ball bearing retainer.
[0003]
As such a segment-shaped cage having a strip shape, for example, there is a technology related to a bearing having a ball bearing cage connected in plural numbers in a circumferential direction (Japanese Patent Publication No. 5-22086).
[0004]
Ball bearing cages include metal cages and plastic cages. Since cost reduction and weight reduction can be achieved, plastic cages are now widely used.
[0005]
The plastic ball bearing retainer is, for example, a plurality of comb-shaped segment type retainers made by plastic injection molding or the like connected in the circumferential direction by fitting or the like.
[0006]
The shape of the comb-shaped segment type retainer is such that when one side end face is continuous and the open side end having the other claw portion is discontinuous, the metal piece is formed by plastic injection molding from the end face side of the segment portion. When a material is injected into a mold, the flow direction and orientation of the injected material are not continuous between one end surface and the other end surface, and molding shrinkage occurs. That is, when the reinforcing fiber is not added, the resin material contracts three-dimensionally, and thus the pocket side is settled on the opening side due to the difference in shape between the opening side and the opposite side of the pocket. Further, when reinforcing fibers are added, the fibers are oriented so that the side opposite to the opening side becomes resistant to molding shrinkage, so that the opening side is relatively settled.
[0007]
Since the molding shrinkage causes the comb-shaped claws to fall, the cage for a ball bearing including the segment-shaped cage having such a comb-like shape causes problems such as applying a brake to the bearing.
[0008]
Such a comb-shaped crawling caused by plastic injection molding can be prevented to some extent by examining the material, mold and the like to be used. However, the materials studied in the past cannot completely prevent the sag. For example, in the method shown in FIG. I couldn't. In the figure, reference numeral 7 denotes a spine.
[0009]
As shown in FIG. 6, a method for preventing the above-mentioned inset by controlling the flow direction, orientation, and the like of the material to be injected by providing an injection port for the material provided in the center of the conventional mold at the side end as shown in FIG. It has been considered, but with a slight effect, it has not been fully resolved.
[0010]
[Problems to be solved by the invention]
In view of the above, an object of the present invention is to provide a ball bearing retainer comprising a comb-shaped segment type retainer having no claw part by plastic injection molding.
[0011]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is for a segment type ball bearing having a plurality of retainer pieces divided in a circumferential direction, each retainer piece having a pocket for keeping balls at a constant interval in a circumferential direction. In the retainer, between each pocket of the retainer pieces, a notch cut out beyond an imaginary line connecting the bottom of each pocket from the end face opposite to the end face on the pocket opening side toward the pocket opening side. It is characterized by having been formed.
[0012]
Hereinafter, the ball bearing retainer of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of an example of a comb-shaped segment type cage constituting the ball bearing cage of the present invention. In the figure, 1 represents a pocket. 2 represents a notch. 3 represents the center of the pocket. 4 represents a pocket center line. 5 represents a virtual line (pocket bottom line) connecting the bottom of the pocket.
The pocket center line 4 is a line connecting the pocket center portions 3.
[0013]
The cage for a ball bearing of the present invention is cut out between the pockets 1 from the end face opposite to the end face on the opening side of the pocket 1 toward the opening side of the pocket 1 beyond the pocket bottom line 5 and the pocket center line 4. The notch 2 is formed.
Since the above-mentioned notch 2 is formed in the above-mentioned ball bearing retainer, when the comb-shaped segment type retainer is formed, the flow direction and the orientation of the material injected into the mold are determined as shown in FIG. As shown in FIG. 2, since the shapes are not linearly continuous in the circumferential direction and the shapes at both ends (the side opposite to the pocket opening side) are similar, there is no difference in molding shrinkage at both ends. In the figure, the dotted lines represent the flow direction and orientation of the material.
[0014]
When the notch 2 is formed from the end face opposite to the end face on the opening side of the pocket 1 toward the opening side of the pocket 1 without exceeding the pocket bottom line 5, the material such as resin and filling fiber injected into the mold is formed. As shown in FIG. 3, the flow direction and orientation of the mold are continuous linearly in the circumferential direction between the pocket bottom line 5 and the end face of the pocket 1 on the closing side, so that the difference in molding shrinkage is different from the pocket opening side and the closing side. And the comb-shaped claw portion is settled. In the figure, the dotted lines represent the flow direction and orientation of the material.
[0015]
The ball bearing retainer is preferably made of a material to which reinforcing fibers are added. The reinforcing fibers are not particularly limited, and include, for example, glass fibers, carbon fibers, whisker fibers, ceramic fibers, metal fibers, and the like which are generally filled for the purpose of improving the strength of a plastic material.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to only these Examples.
[0017]
A mold having the shape shown in FIG. 1 was prepared, a material injection port was provided at an end of the segment portion, a material was injected, and plastic injection molding was performed. Since the material flows continuously between the end face and the other end face, the plastic does not linearly orient linearly on one side end face in the circumferential direction, so that there is no difference in molding shrinkage on both side ends, so that a comb-shaped claw There was no fall in the part.
[0018]
A plurality of such segment-shaped cages are connected in the circumferential direction by fitting as shown in FIG. 7 to form a ball bearing cage.
[0019]
When the conventional comb-shaped segment type cage shown in FIG. 4 was formed by plastic injection molding, these had a large deformation, so when a plurality of them were connected in the circumferential direction, the ball bearing cage was used. Sore.
[0020]
When the ball bearing cage in which the ball bearing occurred was incorporated into the bearing, the outer diameter of the ball bearing cage came into contact with the inner peripheral surface of the outer ring, and at the same time, the inner diameter of the ball bearing cage contacted the outer peripheral surface of the inner ring. As a result, the starting torque was tripled.
[0021]
In order to prevent the above-mentioned sagging, 6,6 nylon without reinforcing fibers, 6,6 nylon with reinforcing fibers and the like were used as materials, but the sagging did not stop.
In addition, plastic injection molding was performed using a mold provided with a plurality of material injection ports at the side end portions as shown in FIG. 6, but the pour was reduced only by 20 to 30%.
[0022]
【The invention's effect】
Since the ball bearing retainer of the present invention has the above-described configuration, the flow direction and the orientation of the material injected into the mold are not linearly continuous in the circumferential direction, and the comb-shaped claw portion is settled. For example, the present invention is suitable for a ball bearing retainer that constitutes a large bearing such as a swivel bearing.
[Brief description of the drawings]
FIG. 1 is a perspective view of an example of a comb-shaped segment type cage constituting a ball bearing cage of the present invention.
FIG. 2 is a view showing a flowing direction and an orientation of a material injected into a mold of a comb-shaped segment type cage constituting the ball bearing cage of the present invention.
FIG. 3 is a view showing a flow direction and an orientation of a material injected into a mold of a conventional comb-shaped segment type retainer.
FIG. 4 is a perspective view of an example of a conventional comb-shaped segment type retainer.
FIG. 5 is a diagram showing an example of backstrip processing added to a mold of a conventional comb-shaped segment type retainer.
FIG. 6 is a view showing an example of a conventional comb-shaped segment type retainer in which a material injection port is provided at a side end portion.
FIG. 7 is a diagram showing a connection method by fitting in the embodiment.
[Explanation of symbols]
1 Pocket 2 Notch 3 Pocket center 4 Pocket center line 5 Pocket bottom line 6 Inlet 7 Back

Claims (3)

A segment type revolving seat ball bearing retainer comprising a plurality of retainer pieces divided in a circumferential direction, each retainer piece having a pocket for keeping balls at a constant interval in a circumferential direction. Between each pocket of the pocket opening side, a notch cut out beyond an imaginary line connecting the bottom of each pocket toward the pocket opening side from the end face on the side of the pocket opening side. pocket opening between portions adjacent the end face Ri one plane near perpendicular to the rotation axis, and the cage for a ball bearing, characterized in that formed by formed by plastic injection molding. The ball bearing retainer according to claim 1 , wherein the retainer is made of a material to which reinforcing fibers are added. 3. The ball bearing retainer according to claim 1, wherein the retainer is made of a material to which at least one type of reinforcing fiber selected from the group consisting of carbon fiber, whisker fiber, ceramic fiber, and metal fiber is added.

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