JPH0765625B2 - Shaft loose fitting structure - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft loose fitting member such as a bearing member formed by molding a plastic material, and a shaft loose fitting structure for the shaft loose fitting member.

(Prior Art) A shaft such as a rotary shaft used in various rotating devices and rotating mechanisms is rotatably supported by a shaft loose fitting member such as a bearing member.

A conventional shaft loose fitting structure is, for example, as shown in FIG. 10, in a shaft hole of a bearing member 1, a shaft 2 having the same diameter over its entire length.
Is rotatably inserted, and the shaft 2 is fitted with stop rings 3 and 3 such as E rings on both sides of the bearing member 1 to prevent the shaft 2 from coming off. When a gear or the like is fixed to the shaft 2, the shaft 2 may be prevented from coming off by locating the gear or the like on the side of the bearing member 1.

(Problems to be Solved by the Invention) According to the conventional loose fitting structure of the shaft, it is necessary to attach the stop rings 3 and 3 to the shaft 2 on both sides of the bearing member 1, and to prevent the shaft 2 from slipping off. However, since the gears and the like need to be integrally mounted on the shaft 2, the number of parts is large and the configuration is complicated. Further, the outer diameter of the shaft 2 and the inner diameter of the shaft hole of the bearing member 1 are Axis 2 due to dimensional variation
There was a quality problem in terms of rotation performance. In particular,
When the bearing member is a plastic material, expansion and contraction due to changes in temperature and humidity are large, and dimensional accuracy is a serious problem.

An object of the present invention is to reduce the number of parts, simplify the configuration, and rationalize the assembly, and improve the clearance accuracy between the shaft loose fitting member such as a bearing member and the shaft. To provide the structure.

(Means for Solving the Problems) The present invention provides a shaft loose fitting member formed by molding a plastic material into a shape having a round hole, and a diameter smaller than the diameter of the round hole of the shaft loose fitting member. And a shaft having a circumferential groove portion having a length in the axial direction larger than the thickness dimension of the shaft loosely fitting member in the axial direction, the shaft having a round groove of the shaft loosely fitting member in the circumferential groove portion. It is characterized by being loosely fitted in the hole.

(Operation) The shaft can be rotated relative to the shaft loose fitting member by supporting the circumferential groove portion by the round hole of the shaft loose fitting member.
The shaft loose fitting member can be insert-molded with a plastic material at a portion of the cylindrical surface other than the circumferential groove portion of the shaft, whereby a round hole along the cylindrical surface of the shaft is formed in the shaft loose fitting member. After molding, if the shaft and the shaft loose fitting member are displaced relative to each other in the axial direction so that the shaft loose fitting member is positioned in the circumferential groove portion of the shaft, the diameter of the round hole of the shaft loose fitting member due to shrinkage of the plastic material after molding. Becomes smaller and fits in the circumferential groove portion of the shaft, the shaft is loosely fitted relative to the shaft fitting member, and the shaft is prevented from coming off from the shaft fitting member.

(Example) Hereinafter, an example of a loose fitting structure of a shaft according to the present invention will be described with reference to the drawings.

1 and 2 show an embodiment of the present invention, wherein FIG. 1 shows an intermediate step of manufacturing and FIG. 2 shows a completed state. In FIGS. 1 and 2, reference numeral 11 is a bearing member as a shaft loose fitting member made by molding a plastic material, and 12 is a shaft made of metal or the like. axis
A peripheral groove portion 13 is formed in the groove 12. The axial length L1 of the circumferential groove portion 13 is larger than the axial thickness dimension L2 of the bearing member 11. Also, assuming that the outer diameter of the shaft 12 is D1, the outer diameter of the circumferential groove portion 13 of the shaft 12 is D2, and the inner diameter of the bearing member 11 in the completed state as shown in FIG. 2 is D3, D1>D3> It has a D2 relationship. Therefore, in the completed state as shown in FIG. 2, the shaft 12 is rotatably supported by the bearing member 11,
Moreover, it is prevented from coming off.

In obtaining such a loose fitting structure of the shaft, first,
12 is inserted into a mold, and a bearing member is formed on a portion of the cylindrical surface other than the circumferential groove portion 13 of the shaft 12 as shown in FIG.
11 is made of plastic material. By doing so, the bearing member 11 and the shaft 12 are in a fitted state, and the bearing member 11 is formed with a round hole along the cylindrical surface of the shaft 12.
After molding the bearing member 11, the bearing member 11 and the shaft 12 are forcibly displaced relative to each other in the axial direction, and the circumferential groove portion 13 of the shaft 12 is positioned in the round hole portion of the bearing member 11. The diameter D3 of the round hole of the bearing member 11 becomes smaller than the outer diameter D1 of the shaft 12 due to contraction after molding, so that the shaft 12 is prevented from coming off, and the bearing member 11 rotatably supports the shaft 12. The relative displacement of the bearing member 11 and the shaft 12 in the axial direction may be performed by relatively shifting the bearing member 11 and the shaft 12 with respect to the shaft 12 in the molding state of the bearing member 11. In this way, the molded product is displaced while it is at a high temperature, so that it can be displaced smoothly. After that, the bearing member 11 made of a plastic material contracts due to the decrease in temperature, the diameter of the round hole portion becomes small, and the shaft 12 is prevented from coming off as described above.

According to the above-mentioned embodiment, the round hole of the bearing member 11 is loosely fitted in the circumferential groove portion 13 of the shaft 12 having the circumferential groove portion 13, and the diameter of the circumferential groove portion 13 of the shaft 12 is smaller than the diameter of the round hole and Bearing member 11
Since the axial dimension of the circumferential groove portion 13 of the shaft 12 is larger than the axial thickness dimension of the shaft 12, it is possible to prevent the shaft from coming off the bearing member 11 without using a retaining ring or the like. Therefore, it is possible to obtain the loose fitting structure of the shaft having a small number of parts and a simple structure. Further, the bearing member 11 is insert-molded to the shaft 12, and then the bearing member 11 and the shaft 12 are relatively displaced in the axial direction to loosely fit the circumferential groove portion 13 of the shaft 12 and the round hole of the bearing member 11. Therefore, the bearing member 11
The round hole is formed so as to be dimensioned along the outer diameter of the shaft 12, and the loose fitting dimensional accuracy of both can be improved as compared with the case where the bearing member 11 is manufactured separately from the shaft 12 and these are combined.

Another embodiment shown in FIGS. 3 and 4 is an example in which the shaft is supported at two points. In FIGS. 3 and 4, the axis
Circumferential groove portions 23, 23 are formed at two locations on 22. The bearing members 21, 21 as two shaft loose fitting members that support the circumferential groove portions 23, 23 are integrally formed of a plastic material, and the circumferential groove portion 23 of the shaft 22 is formed in a round hole formed in the bearing members 21, 21. The shaft 22 is rotatable by loosely fitting the shaft 23.
The axial length of the circumferential groove portions 23, 23 of the shaft 22 is the bearing member 21,
It is larger than the thickness in the axial direction of 21. Also,
Bearing member in a completed state as shown in FIG.
The inner diameters of the round holes 21 and 21 are smaller than the outer diameter of the shaft 22 and larger than the outer diameters of the circumferential grooves 23 and 23 of the shaft 22. Therefore, the axis
22 is rotatably supported by bearing members 21, 21, and
It is locked out.

In the case of the above embodiment as well, as shown in FIG.
The bearing members 21 and 21 are integrally molded with a plastic material in the portion other than the peripheral groove portions 23 and 23 of the shaft 22 in a state where the bearing members 21 and 21 and the shaft 22 are relatively displaced in the axial direction. The finished product as shown in FIG. 4 can be obtained by locating the circumferential groove portions 23, 23 of the shaft 22 in the round hole portions of the bearing members 21, 21. Also, in the case of the above-mentioned embodiment, the same operational effect as that of the above-mentioned embodiment is obtained.

The embodiment shown in FIGS. 5 and 6 is an example in which gears are integrally provided at both ends of the shaft. In FIG. 5 and FIG. 6, the shaft 32 has circumferential groove portions 33, 33 at two locations. The circumferential groove portions 33, 33 are formed on the bearing members 31, 31 as two shaft loose fitting members formed by molding a plastic material. It is freely rotatably fitted in the drilled round hole. Knurls 34, 34 are formed at both ends of the shaft 32, and gears 35, 35 are integrally fixed to the knurls 34, 34. The relationship between the inner diameter of the round hole of the bearing member 31, 31 and the axial thickness dimension, the outer diameter of the shaft 32, and the outer diameter dimension of the circumferential groove portions 33, 33 of the shaft 32 is the same as that of the above-described embodiment. There is.

Also in the case of the above embodiment, first, as shown in FIG. 5, the bearing members 31 and 31 are insert-molded from the plastic material in the portions other than the circumferential groove portions 33 of the shaft 32. At this time gear 3
5 and 35 are made of plastic material, and knurls 34 and 34 of the shaft 32
The position may be insert-molded at the position, or the gears 35, 35 may be fixed to the shaft 32 in advance. After molding the bearing members 31, 31, the bearing members 31, 31 and the shaft 32 are relatively displaced in the axial direction, and the circumferential groove portions 33, 33 of the shaft 32 are loosely fitted in the round hole portions of the bearing members 31, 31. As a result, the shaft 32 integrally including the gears 35, 35 is rotatably supported.

In the case of the above-mentioned embodiment, the same operational effect as that of the above-mentioned embodiment can be obtained.

FIG. 7 shows a mold structure for obtaining the loose fitting structure of the shaft according to the embodiment of FIGS. 5 and 6. In FIG.
The right side die 36 is a fixed side die, and the left side die 37 is a movable side die. Slide cores 38 and 38 for molding the bearing members 31 and 31 with the shaft 32 inserted are arranged between the mold 36 and the mold 37.

When using the mold having the above structure, first, the mold 37 and the slide cores 38, 38 are set at predetermined positions with respect to the mold 36 to mold the bearing members 31, 31, and then the slide cores 38, 38 are illustrated. In, the slide is divided into the front side and the side facing in the direction perpendicular to the paper surface. Next, the bearing members 31, 31 and the shaft 32 are relatively moved in the axial direction so that the round hole portions of the bearing members 31, 31 become the shafts.
It is fitted in the circumferential groove portions 33, 33 of 32, and then the mold 37 is moved in a direction away from the mold 36. With this, the bearing member 31 of the shaft 32,
The loose fitting structure for 31 is completed.

As shown in FIG. 7, the molds 36, 37 are molds for the gears 35, 35, and the gears 35, 35 are formed simultaneously with the molding of the bearing members 31, 31.
The 35 may be insert-molded with a plastic material, or the gears 35, 35 may be fixed to both ends of the shaft 32 in advance, and then the bearing members 31, 31 may be insert-molded.

The shaft loosely fitting member on which the shaft is loosely fitted may be a gear. 8th
Figures and 9 show such an embodiment. In FIGS. 8 and 9, reference numeral 41 is a gear as a shaft loose fitting member formed by molding a plastic material, and the gear 41 is attached to the outer diameter portion of the shaft 42 inserted in the dies 44 and 45. Molded by injection of plastic material, then the shaft
A round hole is formed along the outer diameter portion of 42. Circumferential groove on shaft 42
43 is formed, and after the gear 41 is molded, the gear 41 and the shaft 42 are moved relative to each other in the axial direction to fit the round hole portion of the gear 41 into the circumferential groove portion 43 of the shaft 42. It is loosely fitted in relative rotation. The diameter of the round hole of the gear 41 and the circumferential groove portion 43 of the shaft 42 and the dimensional relationship in the axial direction are the same as those in the above-described embodiment.
In FIG. 8, reference numeral 46 is an injection hole for introducing the plastic material into the molding cavity of the gear 41. The shaft 42 may be fixedly attached to a predetermined support portion or may be rotatably supported.

Also in the case of the above embodiment, when loosely fitting the gear 41 and the shaft 42, it is not necessary to use a stop ring or the like, so that the number of parts can be reduced and the configuration can be simplified. The same action and effect as in the case are achieved.

(Effect of the Invention) According to the present invention, a round hole of a shaft loose fitting member such as a bearing member is loosely fitted in the circumferential groove portion of a shaft having a circumferential groove portion, and the circumference of the shaft is larger than the diameter of the round hole. Since the diameter of the groove portion is small and the axial length of the circumferential groove portion of the shaft is larger than the axial thickness dimension of the shaft loose fitting member, the shaft loose fitting member can be fitted to the shaft loose fitting member without using a stop ring or the like. It is possible to prevent the shaft from coming off, and thus it is possible to provide a loose fitting structure of the shaft which has a small number of parts and a simple structure. In addition, the shaft loose fitting member is insert-molded with the shaft by a plastic material, and then the shaft loose fitting member and the shaft are relatively displaced in the axial direction so that the circumferential groove portion of the shaft and the round hole of the shaft loose fitting member are formed. Since they can be fitted together, the round hole of the shaft loose fitting member can be formed by dimensioning along the outer diameter of the shaft, and it is better than when the shaft loose fitting member is manufactured separately from the shaft and assembled. It is possible to improve the loose fitting dimensional accuracy of both and to rationalize the assembly.

[Brief description of drawings]

FIG. 1 is a partially sectional front view showing a state in the middle of a manufacturing process of an embodiment of a shaft loose fitting structure according to the present invention, FIG. 2 is a partially sectional front view of the same embodiment, and FIG. FIG. 4 is a partially sectional front view showing a state in the middle of a manufacturing process of another embodiment of the shaft loose fitting structure according to the present invention, and FIG.
FIG. 6 is a partially sectional front view showing a state in the middle of a manufacturing process of yet another embodiment of the shaft loose fitting structure according to the present invention, FIG. 6 is a partially sectional front view of the same embodiment, and FIG. Same as above, a partial sectional front view showing an example of a mold structure used to obtain a shaft loose fitting structure, and FIG. 8 is a manufacture of yet another embodiment of the shaft loose fitting structure according to the present invention. FIG. 9 is a partial sectional front view showing the state in the middle of the process, and FIG.
FIG. 10 is a partially sectional front view showing an example of a conventional loose fitting structure of a shaft. 11, 21, 31, ... Bearing members as shaft loose fitting members, 12, 22,
32, 42 ... Shafts, 13, 23, 33, 43 ... Circular groove portions, 41 ... Gears as shaft loose fitting members.

Claims (1)

[Claims] 1. A shaft loose fitting member formed by forming a round hole by molding a plastic material, and a diameter smaller than the diameter of the round hole of the shaft loose fitting member, and of the shaft loose fitting member. A shaft having a peripheral groove portion having a length in the axial direction larger than the thickness dimension in the axial direction, and the shaft having the peripheral groove portion loosely fitted in the round hole of the shaft loose fitting member. A loose fitting structure.