JPH0547853Y2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Purpose of the Invention (Field of Industrial Application) The present invention relates to a structure for fitting a shaft bushing to a shaft, mainly in applications where no radial load is applied.

(Prior Art) The content and configuration of the prior art will be explained with reference to FIGS. 3 to 5.

FIG. 3 is a cross-sectional view showing an example of fixing a shaft 2 and a member to be fastened 3 via a shaft bushing 1 according to the prior art, in which a screw hole is formed in the shaft bushing 1 and tightened with a screw member 4. It is a fixed configuration.

As shown in the figure, in the fixing structure using the screw member 4, the shaft bushing 1 that supports the fastened member 3 has an inner diameter ΦD1 larger than an outer diameter ΦD2 of the shaft 2 to be inserted, so that fitting is facilitated. We are taking the utmost care.

When the screw member 4 is tightened and fixed, the gap ΔS' on the anti-tightening side becomes almost 0, and on the tightening side it is pulled by the screw member 4, so the difference between ΦD1 and ΦD2 becomes the side ΔS and is fixed. Therefore, the difference of ΔS′<ΔS is the difference between the fastened member 3
is the eccentricity with respect to axis 2.

That is, with this configuration, it is impossible to avoid the fact that the diameter difference provided to facilitate fitting becomes an eccentricity error in the mounted state.

Also, FIGS. 4 and 5 show another example of the same prior art, in which an enlarged diameter portion 2-1 with a diameter ΦD2' is formed on the outer diameter ΦD1 of the shaft 2 as shown in FIG. 4 as a means of securing fastening force. The shaft 2 is fastened and fixed to a shaft bushing 1 whose inner diameter ΦD1 is smaller than the diameter ΦD2' of the fitting and fixing part as shown in FIG.

As mentioned above, in this configuration, ΦD1 <ΦD2' constitutes a tightening margin to obtain a fastening force, and since they are directly connected, like the fastening using the screw member 4 shown in FIG. 3,
Although eccentricity does not occur due to the gaps ΔS' and ΔS, the addition of the machining process for the enlarged diameter part 2-1 is not only to simply expand the diameter, but also to ensure that it is concentric with the shaft center so that eccentricity does not occur due to fastening. In order to ensure accuracy, concentric machining of the outer diameter was required, and as a production method, there were problems in the process.

(Problems to be Solved by the Invention) The object of the present invention is to obtain a shaft bushing that can accurately and easily ensure concentricity between the shaft and the fastened member attached to the shaft.

(2) Structure of the invention (Means for solving the problems) The shaft bushing of the invention includes a cylindrical part for fitting the member to be fastened, and an inner circumferential surface of the cylindrical part.
One forms an imaginary arc whose tip portion is larger than the diameter of the shaft into which it is inserted, and the other forms an imaginary arc whose tip portion forms a smaller imaginary arc than the shaft diameter. The axial cross section is branched into a Y-shape so as to be in pressure contact with the surface of the shaft, and it is constructed by integral molding of plastic or the like so as to be able to flex integrally in the axial direction.

(Function) In the configuration described above, since the shaft and the member to be fastened are directly fixed to their inner and outer circumferential surfaces, the accuracy of the concentricity of both depends solely on the inner and outer concentricity of the bushing for the shaft. , it brings about the effect that the fixing can be completed simply by inserting and inserting.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a fastening configuration using a shaft bushing 1 according to the present invention, in which a shaft 2, a member to be fastened 3,
For example, a rotary plate of a photoelectric encoder is connected and fixed by a shaft bushing 1, and in the fastened state, the surface of the shaft 2 has an engaging pawl formed on the inner peripheral surface of the cylindrical portion 1-1 of the shaft bushing 1. A and B are pressed together.

The mechanism from insertion of the shaft 2 to fastening is as follows.

As shown in FIG. 2, when the shaft bushing 1 is in its natural state, one of the engaging claws 1-2 formed on the inner periphery of the cylindrical portion 1-1 has a shaft diameter ΦD2 indicated by a broken line in the same figure. The other engaging claw B1 is formed integrally with a pseudo-cylindrical shape having a larger diameter ΦDA.
-3 is formed to have a diameter ΦDB smaller than the shaft diameter ΦD2, and when the shaft 2 is inserted as shown by the arrow in the same figure, the tip of the shaft 2 first becomes the diameter ΦD of the shaft 2.
The engaging claw B1-3, which is a pseudo circular arc with a diameter ΦDB smaller than 2, is pushed out (solid line arrow in Figure 1), and as the engaging claw B1-3 is bent, the engaging claw A1-, which is integral with this, is expanded. 2 is bent (dashed line arrow in Figure 1), causing the shaft 2 to bend.
The aim is to conclude the agreement with

That is, the shaft bushing 1, and therefore the fastened member 3 and the shaft 2, are connected to an engaging pawl A formed on the inner circumferential surface of the cylindrical portion 1-1 on which the fastened member 3 of the shaft bushing 1 is mounted. The fixing force is obtained by press-contacting the shaft 2 and the shaft 2 at different locations on the surface of the shaft 2.

(3) Effects of the invention Since the shaft bushing of the invention has the above-mentioned configuration, it has the advantage of being able to easily achieve concentricity between the shaft and the fastened member with high accuracy. .

[Brief explanation of the drawing]

Fig. 1 is a sectional view a and a front view b of an example of a fastening structure using the shaft bushing of the present invention, and Fig. 2 is a sectional view a and a front view b showing the natural state of the shaft bushing alone in the example. FIG. 3 is a sectional view of an example of a fastening structure according to the prior art, and FIGS. 4 and 5 show a shaft and a shaft bushing of other examples of the prior art. Explanation of symbols, 1... Shaft bushing, 1-2...
Engagement claw A, 1-3...Engagement claw B, 2...Shaft, 2-
1... Diameter enlarged portion, 3... Member to be fastened, 4... Screw member.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A cylindrical portion for fitting the fastened member in a shaft bushing for a fastened member device mainly used in applications where no radial load is applied to the fastened member. and, on the inner circumferential surface of the cylindrical part, one has an imaginary arc larger than the shaft diameter into which the tip part is inserted, and the other has an imaginary arc whose tip part is smaller than the shaft diameter, and A plurality of engaging pawls A and B are formed, each of which has a branched Y-shaped cross section in the axial direction, so that when the shaft is inserted into the shaft, the ends of the engaging pawls A and B are in pressure contact with the surface of the shaft. Features a shaft bush. (2) The shaft use according to claim 1 of the utility model registration claim, characterized in that the ends of the Y-shaped engaging claws A and B are both integrally flexible in the axial direction. Butsuyuu. (3) The shaft bushing according to claims 1 and 2 of the utility model registration claim, characterized in that the cylindrical portion and the engaging claws A and B on the inner circumference thereof are integrally formed by plastic molding.