JPH051022U - Cylindrical resin cage - Google Patents

Abstract

(57) [Abstract] [Purpose] It is easy to assemble the balls, the balls are held securely, and the resistance is small even when applied to the linear bearings for oil-immersed solenoid valves, and the valve operating response can be improved. A cylindrical resin cage is provided. [Structure] A ball retaining pocket 2 is provided with a ball engaging portion 3 which projects radially outward from an outer peripheral surface of a cylindrical body, an inner peripheral surface 3b thereof is a spherical surface corresponding to a ball diameter of a ball 4, and a rear surface 3a thereof is a ball. Locking part 3
A conical surface having a vertex radially outward of the outer peripheral surface of the cylindrical body on a line connecting the spherical center of the inner peripheral surface 3b and the radial center of the cylindrical body. The ball locking portion 3 is elastically deformed, and holds the ball securely even if the thickness of the cylindrical body is reduced. It also has the function of reducing the oil flow resistance.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cylindrical resin cage in which balls can be easily assembled, can securely hold the assembled balls, and can be easily injection molded.

[0002]

[Prior Art]

 As a conventional resin cage, for example, there is one disclosed in Japanese Utility Model Publication No. 49-136941 (first conventional example). This product has a thin wall between the recess and the ball pocket opening by providing a recess reaching the upper end of the peripheral wall at the portion between the ball pockets on either side of the inner or outer wall of the cage body. It is a synthetic resin crown type bearing cage formed.

In Japanese Utility Model Publication No. 53-5314, a plurality of balls arranged so as to roll between an outer cylinder and an inner cylinder in order to absorb impact energy are balls of a retaining ring made of a synthetic resin. There is disclosed a resin-made cage that is press-fitted and loaded into a ball holding hole and has a dimensional relationship of an inlet diameter of the ball holding hole <ball diameter <maximum inner diameter of the holding hole (second conventional example). On the other hand, in Japanese Patent Application Laid-Open No. 48-14932, a thick cylinder made of synthetic resin is injection-molded by inserting a ball mold, and the ball mold is removed before cooling the cylinder to fit a metal ball. In this case, a ball retainer (third conventional example) formed to hold the ball by utilizing the reduction of the cylindrical body by cooling, and a holding hole for ball fitting are provided in one metal plate, and the holding When the metal plate is made into a cylinder, the hole is provided with a projecting edge that is inclined to be slightly smaller than the ball diameter on the inner surface side and is inclined to be slightly larger than the ball diameter on the outer surface side. There is disclosed a metal ball retainer (fourth conventional example) in which a ball is fitted into the holding hole from the outside and then the outer edge of the ball is compressed to hold the ball in the holding hole.

[0004]

[Problems to be solved by the device]

 However, in the first conventional example, since the peripheral edge of the ball pocket in which the ball is held is only partially thin at the portion between the recess and the ball pocket opening, the ball is incorporated. At this time, there was a problem that the peripheral edge of the ball pocket was not easily deformed, and therefore a large amount of force was required for assembling. Further, there is a problem that it is difficult to remove the pocket inner peripheral surface forming die (pocket pin) during injection molding from the cage.

On the other hand, in the second conventional example, the entrance diameter of the ball holding hole is smaller than the ball diameter within the thickness of the retaining ring made of synthetic resin. As described above, a large amount of force is required for assembling, and if the wall thickness is made thin, it becomes difficult to hold the ball securely.

Further, the third conventional example has a problem in that the molding process is complicated and the dimensional accuracy of the product is difficult to obtain because it is die-cut before cooling, and it is difficult to reliably hold the ball. On the other hand, the fourth conventional example is made of metal and can be made thinner than the synthetic resin of the first to third conventional examples, but it is possible to form a projecting edge for locking the ball or to fit the ball in the holding hole. There is a problem in that the manufacturing process becomes complicated because it is necessary to caulk the edges after combining.

Further, when the cylindrical retainer is applied to the linear bearing for the oil immersion solenoid valve, all of the structures of the above-mentioned first to third conventional examples have a large flow resistance of the oil flowing in the axial direction. In the fourth conventional example, since it is made of metal and weighs about six times as much as resin and has a large inertial force, there is a problem that the response in the axial movement is poor and it is unsuitable.

Therefore, an object of the present invention is to solve the above-mentioned problems of the related art, and the molding, the assembling of the balls, etc. are easy and the manufacturing is easy, and the balls can be surely held, and the weight is light and the axial direction is good. It is an object of the present invention to provide a cylindrical resin cage which has a low fluid flow resistance and can improve the operation response of the valve when applied to a linear bearing for an oil immersion solenoid valve.

[0009]

[Means for Solving the Problems]

 The present invention for achieving the above object relates to a cylindrical resin cage having a plurality of ball retaining pocket rows arranged at equal intervals on a circumference perpendicular to the axis of the cylindrical body in the axial direction of the cylindrical body. The ball holding pocket has a ball engaging portion that projects radially outward from the outer peripheral surface of the cylindrical body, and the inner peripheral surface of the ball engaging portion has a spherical surface corresponding to the ball diameter. On the other hand, the back surface of the ball engaging portion is a conical surface having a vertex radially outward of the outer peripheral surface of the cylindrical body on a line connecting the center of the spherical surface on the inner peripheral surface of the ball engaging portion and the radial center of the cylindrical body, Alternatively, it is characterized by comprising a spherical surface having a radius larger than the radius of the inner peripheral portion of the ball locking portion and smaller than the radius of the outer peripheral surface of the cylindrical body.

[0010]

[Action]

 The cylindrical resin cage can be easily manufactured by injection molding. The ball locking portion consisting of a spherical inner surface and a conical outer surface has a thin end and is easily elastically deformed. To fit a ball into this ball holding pocket, elastically deform the ball locking part and open it. After the ball is inserted, the ball locking part elastically restores and holds the ball. By sufficiently projecting the ball locking part of the cylindrical body from the cylindrical body, the ball can be held securely, and the wall thickness of the cylindrical body can be reduced to reduce the axial fluid flow resistance.

[0011]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 1 to 4 show an embodiment of the present invention. FIG. 1 is a front view of a cylindrical resin cage, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is a partially enlarged sectional view of FIG. FIG. 4 and FIG. 4 are schematic cross-sectional views illustrating a state in which balls are fitted into the cage and mounted between the bearing outer ring and the shaft.

The cage 1 is a cylinder made of synthetic resin, and has a plurality of rows of ball holding pockets 2 arranged at equal intervals on the circumference perpendicular to the axis of the cylinder in the axial direction. .. The ball holding pockets 2 in adjacent rows are staggered with their phases shifted in the circumferential direction. Each of the ball holding pockets 2 has a ball locking portion 3 which annularly projects from the outer peripheral surface 1A toward the outer side in the radial direction of the cylindrical body at the edge of the opening on the outer peripheral surface 1A side of the cylindrical body. .. The inner peripheral surface 3b of the ball locking portion 3 forms a spherical surface corresponding to the ball diameter of the ball 4 and forms a part of the spherical inner peripheral surface 2b of the ball holding pocket 2. On the other hand, the back surface 3a of the ball locking portion 3 is a conical surface or a spherical surface. That is, the center O ₁ of the spherical inner peripheral surface 3b of the ball locking portion 3 (which is also the center of the spherical inner peripheral surface 2b of the ball holding pocket 2) and the axis O of the cage 1 which is the radial center of the cylindrical body. _On the line L connecting the ₂ and _2, it is larger than the conical surface having the apex T radially outward of the outer peripheral surface 1A of the cylindrical body or the spherical half diameter of the inner peripheral surface of the ball locking portion 3 and the cylindrical body. It is composed of a spherical surface having a radius smaller than the radius of the outer peripheral surface. The inner peripheral surface 1B side of the cylindrical body of the ball holding pocket 2 is directly opened to the inner peripheral surface 1B without having a ball engaging portion.

The cage 1 configured as described above is lightweight and mechanically formed by molding a synthetic resin in which glass fibers are mixed in a range of 10 to 40% by weight, particularly polyphenylene sulfide resin (PPS resin). High strength, extremely small dimensional change due to swelling, and excellent heat resistance and oil resistance can be obtained. If the mixing ratio of the glass fibers is less than 10% by weight, the mechanical strength and dimensional stability of the cage product are not good. On the other hand, if it exceeds 40% by weight, the moldability is deteriorated. The cage 1 of this example is manufactured by injection molding using a PPS resin "Fuatron KPS, W-200" (trade name, containing 20% by weight of glass fiber) manufactured by Kureha Chemical Industry Co., Ltd. ..

FIG. 5 shows a cage assembly H assembled by inserting the balls 4 into the cage 1 described above, for example, an oil incorporated in a hydraulic circuit for mitigating gear shift shock of an automobile, a power steering hydraulic circuit, or the like. FIG. 7 is a vertical cross-sectional view showing a case where the immersion solenoid valve is applied as a linear bearing of a plunger shaft. In the figure, 6 is a shaft fixed to a plunger 8 of a solenoid, 7 is a coil for attracting the plunger 8 against the elasticity of a return spring 9, 10 is a core, 11 is an outer cylinder, 12 is a spacer, 13 Is a spool that moves in the axial direction to open and close the hydraulic circuit. The cage assembly H is mounted between the bearing outer ring 5 fitted on the inner peripheral surface of the core 10 and the outer peripheral surface of the shaft 6. The inside of the outer cylinder 11 is filled with oil, and the cage assembly H is immersed in the oil.

Next, the operation will be described. The cage 1 has a ball locking portion 3 provided on the outer peripheral edge of the opening of the ball holding pocket 2 such that the inner peripheral surface 3b thereof is a spherical surface and the back surface thereof is a conical surface or a spherical surface. As a result, the ball locking portion 3 gradually becomes thinner from the base to the tip, and the thin tip is easily elastically deformed, while the base that is thick and curved inward inward has a large elastic restoring force and ball holding force. .. Therefore, when inserting the ball 4 into the ball holding pocket 2, if the ball 4 is pressed against the tip of the ball locking portion 3, the tip easily elastically deforms and the opening of the ball holding pocket 2 expands. Therefore, the ball 4 can be incorporated into the ball holding pocket 2 with a small force. In addition, the ball locking portion 3 is projected outward in the radial direction of the cylinder to secure a sufficient radial length for holding the ball 4 having a diameter larger than the radial thickness of the cylindrical cage. , The incorporated ball 4 can be securely held. As can be seen from the above explanation, it is essential that the ball engaging portion 3 of the cage 1 is gradually thinned from the base portion to the tip, and the back surface shape is a conical surface or a polygonal surface other than a spherical surface. You can have it.

Further, when the cage 1 is manufactured by injection molding, the pocket pin forming the spherical inner peripheral surface 2b of the ball holding pocket 2 is easily pulled out of the cage 1, so that the ball locking portion 3 is prevented from being broken. can do. Therefore, the cage 1 of this embodiment is easy to manufacture. When the cage assembly H in which the balls 4 are fitted in the cage 1 is used by being assembled in the oil immersion solenoid valve as shown in FIG. 5, the operation is as follows.

In FIG. 5, when the coil 7 is energized and excited, the plunger 8 is attracted by the coil 7 against the biasing force of the return spring (not shown) and the shaft 6 moves to the right in the figure. Then, the spool 13 is pressed. At this time, as the plunger 8 moves to the right, oil flows from the plunger 8 side toward the spool 13 side. The pushed spool 13 moves to the right in the axial direction to switch the hydraulic circuit. When the current to the coil 7 is cut off, the plunger 8 and the shaft 6 are elastically pressed by the return spring and move to the left in the figure. At this time, the oil flows from the spool 13 side toward the plunger 8 side, contrary to the above.

In the above-mentioned on / off operation of the solenoid valve, the movement of the shaft 6 is guided to the cage assembly H. That is, the balls 4 incorporated in the cage assembly H are in contact with the outer peripheral surface 6a of the shaft 6 and the inner peripheral surface 5a of the bearing outer ring 5 and move while rolling with the movement of the shaft 6. Accordingly, the cage 1 also moves in the axial direction. By the way, in this case, as shown in FIG. 4, the outer peripheral surface 1A of the cylindrical body of the cage 1 of the cage assembly H, which is interposed between the bearing outer ring 5 and the shaft 6, and the inner periphery of the bearing outer ring 5. There is a clearance ΔR with the surface 5A, and the oil in the valve flows through this clearance ΔR when the shaft 6, the plunger 8, and the cage assembly H move. In the cage 1 of the present invention, however, the wall thickness of the cylindrical body can be made thin to make the gap ΔR large, and therefore the viscous resistance due to oil against the axial movement of the cage assembly H can be reduced. Have. As a result, it is possible to move the shaft 6 and the plunger 8 at high speed in the axial direction, and to improve the operation response of the oil immersion solenoid valve.

The cage 1 of this embodiment can be easily manufactured by injection molding using PPS resin in which glass fibers are mixed in an appropriate amount as a material. Further, the PPS resin is a resin excellent in high temperature oil resistance, heat resistance, and chemical resistance. Therefore, the cage 1 is not only lightweight, but also has high oil resistance and heat resistance. It was experimentally confirmed that even when incorporated into an oil-immersed solenoid valve, swelling due to oil was small, and it could be used continuously for a long period of time at high temperatures up to 180 ° C, maintaining stable performance.

By the way, in the conventional resin cage, phenol resin, polyamide resin, and polyacetal resin are often used as resin materials. However, since phenol resin cannot be injection-molded, it is troublesome to perform cutting work, drilling, etc. Such machining is necessary, resulting in high cost. In addition, polyamide resins and polyacetal resins have problems in heat resistance and oil resistance, and cages made of these resin materials will age with contact with oil containing extreme pressure additives at temperatures of 115 ° C or higher. It is not suitable for use in the above oil-immersed solenoid valve because it deteriorates over time and cannot stabilize its performance for a long period of time.

[0021]

[Effect of the device]

 As described above, in the cylindrical resin cage according to the present invention, the ball retaining pocket is provided with the ball locking portion that projects outward in the radial direction from the outer peripheral surface of the cylindrical body. The peripheral surface has a spherical surface that corresponds to the diameter of the ball, and the back surface is located radially outward of the outer peripheral surface of the cylinder on the line connecting the spherical center of the inner peripheral surface of the ball locking part and the radial center of the cylindrical body. A conical surface having an apex or a spherical surface having a radius larger than the radius of the inner peripheral surface of the ball locking portion and smaller than the radius of the outer peripheral surface of the cylindrical body is adopted. Therefore, it can be easily manufactured by injection molding, the ball can be easily incorporated into the ball holding pocket by utilizing the elastic deformation of the ball locking part, and the thickness of the cylindrical body is thin. It is possible to cover the ball sufficiently with the protruding length of the locking part to securely hold the ball, and it is also possible to reduce the flow resistance of the fluid in the axial direction. It is said that it is possible to provide a cylindrical resin cage that can be easily assembled, can securely retain the assembled balls, and can improve the valve operating response when applied to a linear bearing for oil-immersed solenoid valves. The effect is obtained.

[Brief description of drawings]

FIG. 1 is a front view of a cylindrical resin cage according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a partially enlarged sectional view of FIG.

FIG. 4 is a schematic cross-sectional view illustrating a state in which balls are fitted in the cage and mounted between the bearing outer ring and the shaft.

FIG. 5 is a vertical cross-sectional view showing a case where the cage assembly is applied as a linear bearing of a plunger shaft of an oil immersion solenoid valve.

[Explanation of symbols]

 1 cage 2 ball holding pocket 3 ball locking part 3a back surface 3b inner peripheral surface 4 ball

Claims (1)

[Claims for utility model registration] 1. A cylindrical resin cage having a plurality of ball retaining pocket rows arranged at equal intervals on a circumference perpendicular to the axis of the cylindrical body in the axial direction of the cylindrical body. In, the ball holding pocket has a ball locking portion that projects outward in the radial direction from the outer peripheral surface of the cylindrical body, and the inner peripheral surface of the ball locking portion has a spherical surface corresponding to the ball diameter. The rear surface is a conical surface having a vertex radially outward of the outer peripheral surface of the cylindrical body on a line connecting the center of the spherical surface on the inner peripheral surface of the ball locking portion and the radial center of the cylindrical body. Cylindrical resin cage.