JPS6192309A - Press-in part - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION 70 OBJECTS OF THE INVENTION (1) Field of Industrial Application The present invention relates to a press-fit part that is press-fitted into a press-fit hole having a circular cross section formed in a press-fit member.

(2) Conventional technology Conventionally, this type of press-fit component has a deformable portion having an arc-shaped outer circumferential surface to expand the diameter of the press-fit hole by elastically deforming the circumferential wall of the press-fit hole, and a deformable portion connected to the deformed portion to expand the press-fit hole. and a crimping portion that tightly fits into the press-fit hole after the diameter.

(3) Problems to be Solved by the Invention However, in the press-fitted part, the outer peripheral surface of the deformed part is formed in an arc shape, so the arc-shaped outer peripheral surface easily slips against the press-fit hole mouth edge. There are five problems: positioning is troublesome and accuracy workability is poor.

In addition, the arcuate outer peripheral surface of the deformed part is formed by polishing with a puff or turning-centerless finishing, so in the case of the former polishing with a puff, the boundary line between the deformed part and the crimped part is wavy and constant. In the latter case, when turning with a cutting tool, if the cutting tool has a large amount of cutting, a stepped part will be created at the boundary between the deformed part and the crimped part even if centerless finishing is performed, whereas if the cutting tool has little cutting There is also the problem that quality is not constant, such as the radius of curvature of the deformed part becoming small due to centerless finishing, and quality control is difficult.

In view of the above, an object of the present invention is to provide a press-fit component that has good press-fit workability and is easy to control quality.

B1 Structure of the Invention (1) Means for Solving Problems The press-fit component according to the present invention has a tapered outer peripheral surface that slopes upward from the front side toward the rear side in the press-fit direction, and elastically deforms the peripheral wall of the press-fit hole. a deformed portion that expands the diameter of the press-fit hole; and a crimp portion that is connected to a large diameter end of the deformed portion and has a circular cross section that tightly fits into the press-fit hole after the diameter has been expanded. do.

(2) Operation Since the deformed portion has a tapered outer circumferential surface, the press-fit part is correctly positioned at the press-fit hole mouth edge via the tapered outer circumferential surface, and then the press-fit hole is expanded in diameter by the deformed portion, and then expanded. The crimp portion fits tightly into the press-fit hole.

(3) Embodiment FIGS. 1 to 7 show a first embodiment in which an iron-based valve seat 1 as a press-fitted part is press-fitted into a cylinder head Eα of an aluminum alloy-based engine E, which is a press-fitted member.

In FIG. 1, a press-fit hole 3 having a circular cross section is formed at the inlet of an exhaust boat 2 of a cylinder head Eα, and a valve seat 1 is press-fitted into the press-fit hole 3. 4 is an exhaust valve.

In FIG. 2, the valve seat 1 has a tapered outer peripheral surface 5α with an upward slope toward the rear from the front end surface in the press-fitting direction,
A guide portion 5 whose large diameter end is formed to be smaller in diameter than that of the press-fit hole 3, and a press-fit hole 3 formed by elastically deforming the circumferential wall of the press-fit hole 30.
In order to increase the diameter of the deformable part 6, the deformable part 6 has a tapered outer peripheral surface 6α having a gentler slope than the tapered outer peripheral surface 5α of the guide part 5 and is connected to the large diameter end of the guide part 5, and the deformable part 60 has a large diameter end. The crimping portion 7 has a circular cross section and is connected to the crimping portion 7 and tightly fits into the press-fit hole 3 after its diameter has been expanded.

With this configuration, the guide portion 5, the deformable portion 6, and the crimp portion 7 can be formed by turning, so that the quality of the valve seat 1 can always be kept constant and its quality control can be performed easily.

When the valve seat 1 is press-fitted into the press-fit hole 3, the guide part 5 of the valve seat 1 is inserted into the press-fit hole 3 as shown in FIG. The valve seat 1 is positioned by engaging with the edge of the press-fit hole 30.

Next, by pressing the end face of the crimping part 7, as shown in FIG. The crimp part 7 is tightly fitted to the part. In this case, since the boundary portion 8 between the guide portion 5 and the deformable portion 6 is located outside the elastic deformation α, the elastic deformation of the press-fit hole peripheral wall is performed smoothly.

When the end surface of the guide portion 5 abuts against the inner end surface of the press-fit hole 3, the press-fitting operation is stopped. The connecting portion between the inner circumferential surface and the inner end surface of the press-fit hole 3 is formed into an arcuate surface 3a, but the outer circumferential surface 5a of the guide portion 5 is formed into a tapered surface, so that the valve seat 1 and the arcuate surface 3α interfere with each other. There's nothing to do.

The inclination angle θ of the tapered outer circumferential surface 6α of the deformed portion 6 with respect to the outer circumferential surface of the crimp portion 7 is set to 3°≦θ≦12°,
This prevents the valve seat 1 from galling the inner peripheral surface of the press-fit hole 3.

In order to securely hold the valve seat 1 in the press-fit hole 3, a predetermined press-fit depth β is required from the end surface of the crimped portion 7 of the valve seat 1. Therefore, if the inclination angle θ exceeds 12°, θ, Then, as shown by the chain line in Fig. 6, the inclination angle θ
is less than 3 degrees and becomes θ2, as shown by the chain line in FIG.
When press-fitting, the boundary portion 8 abuts against the edge of the press-fit hole 3 and scrapes the inner circumferential surface of the press-fit hole 3, causing galling on the inner circumferential surface.

FIG. 8 shows a second embodiment in which a ball bearing 9 as a press-fit part is press-fitted into a press-fit hole 3 of a bearing holder 10 as a press-fit member, and the outer race 9α of the ball bearing 9 has a guide portion 5, It is composed of a deformable part 6 and a crimp part 7. Further, the inclination angle θ of the tapered outer circumferential surface 6α in the deformable portion 6 is also set in the same manner as described above.

C1 Effects of the Invention According to the present invention, since the press-fitted part is constituted by a deformed part having a tapered outer circumferential surface and a crimping part with a circular cross section connected to the deformed part, the tapered outer circumferential surface of the deformed part The press-fitting part can be easily positioned by engaging with the press-fitting hole mouth edge, and the part can be accurately press-fitted into the press-fitting hole, resulting in good press-fitting workability.

Furthermore, since the deformed part and the crimped part can be formed by turning, the press-fit parts can be manufactured easily, and the quality can be kept constant and quality control can be performed easily.

[Brief explanation of the drawing]

Figures 1 to 7 show a first embodiment of the present invention, Figure 1 is a sectional view of the engine, Figure 2 is a perspective view of the valve seat, and Figures 3 to 5 are explanatory diagrams of the press-fitting process of the valve seat. , 6 and 7 are explanatory diagrams showing the relationship of the inclination angle of the deformed portion with respect to the crimped portion, and FIG. 8 is a sectional view of a second embodiment of the present invention. 1.9... Valve seat and ball bearing as press-fit parts, 3... Press-fit hole, 6... Deformed part, 6a...
・Tapered outer circumferential surface, 7...Crimping portion, E, 10...Engine as press-fitted member, bearing holder Patent applicant Honda Motor Co., Ltd. No. 5WJ Fig. 3 Fig. 7 Fig. 6 Fig. 8 Procedural amendment Yoshikawa April 22, 1985 Display of the case 1988 Patent Application No. 214005 Name of the invention Press-fit parts ■ Person who makes corrections Relationship to the case Patent applicant name Title (532) Honda Motor Co., Ltd. Hiki Toshihito 105 Telephone Tokyo 434-4151 1 Positive object

Claims (1)

[Claims] The press-fit part is press-fitted into a press-fit hole with a circular cross section formed in a press-fit member, and has a tapered outer peripheral surface that slopes upward from the front side toward the rear side in the press-fit direction, and the peripheral wall of the press-fit hole is elastically deformed. a deformed portion that expands the diameter of the press-fit hole; and a crimp portion that is connected to a large diameter end of the deformed portion and has a circular cross section that tightly fits into the press-fit hole after the diameter has been expanded. Press-fit parts.