JPH0433568Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the structure of an assembly having a portion into which a shaft or the like is press-fitted, such as a guide roller for a video tape recorder.

[Conventional technology]

FIG. 8 shows this type of guide roller assembly. The lower flange 18 is fixed to the stainless steel shaft 11 by press fitting, and the lower flange 18
A guide roller 19 made of synthetic resin is rotatably mounted on the shaft 11, and an upper flange 12 is press-fitted onto the shaft 11 on the guide roller 19.

As shown in FIG. 9, the upper flange 12 has a press-fit hole 13 with a circular cross-sectional shape corresponding to the shaft 11 with a circular cross-sectional shape, and a taper to prevent the magnetic tape from running over due to vibration during running. Part 1
4, an abutment surface 15 that receives pressure from a jig A to be described later, and a groove 16 into which the tip of the jig A is aligned and inserted. When fitting the upper flange 12, after attaching the guide roller 19 to the shaft 11, insert the tip of the jig A into the groove 16 of the temporarily fitted upper flange 12, press it while rotating, and press it against the shaft 11. Positioning will be performed. In this way, the guide roller 19 and the upper flange 12 are held in place along with the lower flange 18 that was press-fitted earlier.

[Problem that the invention attempts to solve]

However, in the case of the guide roller assembly described above, the press-fit hole 13 of the upper flange 12 requires extremely high roundness to match the shaft 11 in a tight fit relationship. However, the necessary roundness cannot be obtained with sintered metal or press forming, and for this reason, conventionally, a cutting process is indispensable for forming the press-fit hole 13, and as a result, the mass productivity of the upper flange 12 is improved. It was difficult. Lower flange 18
The same applies to .

Furthermore, when forming the groove 16, it is necessary to take measures to prevent burrs from forming on the inner wall of the press-fit hole 13, which would occur if the groove 16 intersects with the press-fit hole 13. That is,
As shown in FIG. 10, a relief hole 17 must be formed in the upper part of the press-fit hole 13, and the groove 16 must intersect with the relief hole 17, which increases the number of processing steps and increases the manufacturing cost. There were some inconveniences.

Furthermore, careful attention was required to align the shaft 11 to be press-fitted with the press-fit hole 13, and to perform the press-fitting operation while rotating and pressing the upper flange 12, making the assembly work troublesome. In view of the above circumstances, it is an object of the present invention to provide a guide roller assembly that is excellent in mass productivity and can be easily press-fitted.

[Means and actions for solving problems]

The guide roller assembly according to the present invention forms, for example, a polygonal press-fit hole that can be partially pressed into contact with the upper flange on the outer peripheral surface of the shaft that is press-fitted with the upper flange (the same applies to the lower flange). Accordingly, the upper flange is configured to fit onto the shaft. Therefore, the cross-sectional shapes of the fitting portions of the upper flange and the shaft are circular on one side and polygonal on the other, and both have high roundness as in the past. It is never circular. As a result, the dimensional accuracy of the press-fit hole of the upper flange can be relaxed, and cutting of the press-fit hole is no longer necessary, and for example, formation of sintered metal can be applied, and the press-fit hole can be accurately press-fitted with the shaft. Work becomes easier.

〔Example〕

1 to 3 show a first embodiment of a guide roller assembly according to the present invention. 1 is a metal shaft having a circular cross-sectional shape; 8 is a lower flange molded from sintered metal or the like and fitted to the underside of the shaft 1; 9 is a synthetic material rotatably attached to the shaft 1; The guide roller 2 made of resin is an upper flange molded from sintered metal or the like and fitted onto the shaft 1 above the guide roller 9. Thus, there is an appropriate gap between the upper flange 2 and the guide roller 9 so as not to hinder the rotation of the guide roller 9.

The upper flange 2 has the following parts.
Reference numeral 3 indicates a press-fit hole whose cross-sectional shape is polygonal, that is, a hexagonal shape in contact with the circumference of the shaft 1 in the example shown in FIG.
is the jig B when press-fitting the shaft 1 into the press-fitting hole 3.
A contact surface 6 pressed by the lower surface a occupies the upper part of the press-fit hole 3, and when press-fitting the upper flange 2 to the shaft 1, a protrusion a' whose cross-sectional shape is hexagonal at the tip of the jig B This is a hexagonal square hole into which the upper flange is rotated by jig B. The lower flange 8 also has a press-fit hole, and the shaft 1 is inserted into the press-fit hole.
is press-fitted, and the lower flange 8 is fitted to the lower side of the shaft 1.

Since the guide roller assembly according to the present invention has the above-mentioned configuration, the press-fit hole 3 of the upper flange 2, which has a hexagonal cross-section, has a higher height than the conventional shaft 1, which has a circular cross-section. Precision dimensions are no longer required. Even if the upper flange 2 is made of sintered metal that can be mass-produced, the shaft 1
Since appropriate dimensional accuracy of the press-fit hole 3 can be ensured, conventional cutting is not required, and as a result, manufacturing costs can be reduced by reducing manufacturing man-hours, shortening manufacturing time, etc.

Furthermore, when press-fitting the upper flange 2 into the shaft 1, vertical alignment of the two is much easier than in the conventional case where both have circular cross-sectional shapes. In particular, if the lower end opening of the press-fit hole 3 is tapered, this will become easier.
Furthermore, the protrusion a' of the jig B is inserted into the square hole 6 of the upper flange 2, and the jig B is rotated while pressing the contact surface 5 with the lower surface a of the jig B to easily and properly attach the upper flange 2 to the shaft 1. Can be press-fitted securely.

FIG. 4 is a cross-sectional view of the fitting portion between the shaft 1 and the upper flange 2 in the second embodiment, and FIG. 5 shows the upper flange 2 in cross section taken along the line -- in FIG. The cross-sectional shape of the press-fit hole 3 of the upper flange 2 is hexagonal, and the square hole 6 in the upper part of the press-fit hole 3
is similar in cross-sectional shape to the above-mentioned hexagon and is formed slightly larger. Insert the jig B so that the lower end of the protrusion a' is in contact with the lower surface of the upper square hole 6 of the press-fit hole 3, press fit while rotating the upper flange 2, and connect the upper end of the shaft 1 with the jig B. If the upper flange 2 is properly positioned on the shaft 1 when the lower end of the protrusion a' comes into contact with the lower end of the protrusion a', the press-fitting operation will be more appropriate and easier.

The cross-sectional shape of the third embodiment is shown in Fig. 6 and Fig. 6-
A vertical cross-sectional shape of the upper flange 2 is shown in FIG. In the third embodiment, the cross-sectional shape of the press-fit hole 3 of the upper flange 2 is circular, and the cross-sectional shape of the square hole 6 in the upper part of the press-fit hole 3 is hexagonal. The cross-sectional shape of the upper fitting part is hexagonal.
The same press-fitting effect as in the example can be obtained. In addition, the shapes of the press-fit hole 3 of the upper flange 2 and the upper fitting part and the lower fitting part of the shaft 1 in each of the above embodiments may be in an inverse relationship to each other.

Furthermore, although only the upper flange 2 has been described above, the same can be applied to the lower flange 8, and in either case, an appropriate and simple press-fitting operation can be performed. In the present invention, the upper flange 2 and the lower flange 8 can be manufactured not only from sintered metal but also by press working. In this case too, manufacturing cost savings result.

[Effect of idea]

As described above, the guide roller assembly according to the present invention has advantages such as improving the mass productivity of flanges and making the assembly of the guide roller accurate and simple.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the guide roller assembly of the present invention, in which FIG. 1 is a longitudinal sectional view of the overall structure, FIG. 2 is a perspective view of the upper flange, and FIG. 1, FIG. 4 is a cross-sectional view of the fitting portion between the shaft and the upper flange in the second embodiment, FIG. 5 is a cross-sectional view of the upper flange taken along the line - in FIG. 4, and FIG. 7 is a cross-sectional view of the fitting portion between the shaft and the upper flange in the third embodiment, FIG. 7 is a cross-sectional view of the upper flange taken along the line - in FIG. 6, and FIG.
The figure is a vertical cross-sectional view of a conventional guide roller assembly.
1 and 10 are a perspective view and a vertical sectional view showing an upper flange of a conventional guide roller assembly. 1... Shaft, 2... Upper flange, 3... Press-fit hole, 4... Taper part, 5... Contact surface, 6... Square hole, 8... Lower flange, 9... Guide roller, B
……jig.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A guide roller is rotatably installed between upper and lower flanges fitted to the shaft, and the cross-sectional shape of the fitting portion between the press-fit hole of the flange and the shaft. 1. A guide roller assembly, characterized in that said circular and polygonal shapes are in contact with each other, and the fitting surfaces are formed so as to partially press against each other. (2) The scope of the utility model registration claim (1) characterized in that the cross-sectional shape of the press-fit hole is polygonal, and the cross-sectional shape of the upper part of the press-fit hole is similar to and slightly larger than the polygon. ) Guide roller assembly as described in ). (3) The cross-sectional shape of the press-fit hole is circular, the cross-sectional shape of the upper part of the press-fit hole is polygonal, and the cross-section of the shaft at the fitting portion between the press-fit hole and the shaft; The guide roller assembly according to claim (1) of the utility model registration, characterized in that the shape is polygonal.