JPS6192308A - 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 A0 Object of the Invention (1) Industrial Application Field 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 been designed to expand the diameter of the press-fit hole by elastically deforming the peripheral wall of the press-fit hole (a deformed part having an arcuate outer peripheral surface and a deformed part connected to the deformed part). and a crimping portion that tightly fits into the press-fit hole after diameter expansion.

(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 is a problem that positioning is troublesome and the correct size workability is poor.

In addition, the arcuate outer circumferential 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. 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, and on the other hand, if the cutting tool has a small amount of cutting. Due to the centerless finishing process, the radius of curvature of the deformed portion becomes smaller, resulting in inconsistent quality, making quality control difficult, and furthermore, there are problems in that galling is likely to occur on the inner circumferential surface of the press-fit hole.

In view of the above, an object of the present invention is to provide a press-fitting part that has good press-fitting workability, easy quality control, and does not cause galling of the inner circumferential surface of the press-fitting hole.

B0 Structure of the Invention (1) Means for Solving Problems The press-fit part according to the present invention is a press-fit part that is press-fitted into a press-fit hole with a circular cross section formed in a press-fitted member, and is a deformable part having a tapered outer circumferential surface with an upward slope from the front side to the rear side and expands the diameter of the press-fit hole by elastically deforming the peripheral wall of the press-fit hole; and a crimping portion having a circular cross section that closely fits into the press-fit hole after the diameter, and an inclination angle of the tapered outer circumferential surface of the deformed portion with respect to the crimping portion is set to 3° or more and 12° or less. (2) Since the action deformation part has a tapered outer circumferential surface, the press-fit part is correctly positioned on the press-fit hole mouth edge via the tapered outer circumference, and then the diameter of the press-fit hole is expanded by the deformation part, Thereafter, the crimping part fits tightly into the press-fit hole whose diameter has been enlarged.Furthermore, when the inclination angle of the tapered outer circumferential surface in the deformed part is specified as described above, the peripheral wall of the press-fit hole is smoothly elastically deformed by the deformed part, and the press-fitting part is press-fitted. The diameter of the hole can be expanded, and galling does not occur on the inner peripheral surface of the press-fit hole.

(3) Example - Figures 1 to 7 are iron-based valve seats 1 as press-fit parts.
A first embodiment is shown in which the cylinder head Ea of an aluminum alloy engine E, which is a press-fitted member, is press-fitted into the cylinder head Ea.

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

In FIG. 2, the valve seat 1 has a tapered outer peripheral surface 5a with an upward slope toward the rear from the front end surface in the press-fitting direction, and the diameter of the large diameter end is smaller than that of the press-fitting hole 3 (formed guide portion 5a). In order to expand the diameter of the press-fit hole 3 by elastically deforming the circumferential wall of the press-fit hole 30, a tapered outer circumferential surface 6a having a gentler slope than the tapered outer circumferential surface 5a of the guide section 5 is connected to the large diameter end of the guide section 50. It consists of a deformable part 6 provided therein, and a crimping part 7 having a circular cross section that is continuous with the large diameter end of the deformable part 60 and tightly fits into the press-fit hole 3 after the diameter has been enlarged.

With this configuration, the guide portion 5, the deformed portion 6, and the crimping portion 7 can be formed by turning, so that the quality of the valve seat 10 can be kept constant and easily controlled.

When press-fitting the valve seat 1 into the press-fit hole 3, insert the valve seat 10 guide part 5 into the press-fit hole 3 as shown in FIG. The valve seat 1 is positioned by engaging the intermediate portion of the tapered outer peripheral surface 6a of the deformable portion 6 with the edge of the press-fit hole 30.

Next, by pressing the end face of the crimping part 7, the tapered outer circumferential surface 6a of the deforming part 6 elastically deforms the circumferential wall of the press-fit hole 30 to enlarge the diameter of the press-fit hole 3, as shown in FIG. The crimping part 7 is tightly fitted to the crimped 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 continuous 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 guide portion 5
Since the outer circumferential surface 5Q of is formed as a tapered surface, there is no interference between the valve seat 1 and the arcuate surface 3a.

The inclination angle θ of the tapered outer circumferential surface 6a of the deformed portion 6 with respect to the outer circumferential surface of the crimp portion 7 is set to 3°≦θ≦12°,
This K 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 -Al is required from the end face of the crimped portion 7 of the valve seat 1, and therefore, the inclination angle θ exceeds 12° and θ1. Then, Figure 6'2. -As is clear, when the inclination angle θ is less than 3° and becomes θ2, Fig. 7 1H1
As shown in i and i4, the boundary portion 8 between the guide portion 5 and the deformable portion 6 is located within the elastic deformation a, so when the valve seat 1 is press-fitted into the press-fit hole 3, the boundary portion 8 is 3 and scrapes the inner peripheral surface of the press-fit hole 3, causing galling on the inner peripheral surface.

FIG. 8 shows a second embodiment in which a ball bearing 9 as a press-fitted part is press-fitted into a press-fit hole 3 of a bearing holder 10 as a press-fitted member, and the accrace 9σ of the pole bearing 9 is the same as the guide part 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 6a of 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, the part can be accurately press-fitted into the press-fitting hole, and the correct size workability is good.

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.

Furthermore, by specifying the inclination angle of the tapered outer circumferential surface of the deformed portion as described above, the diameter expansion work of the press-fit hole by the deformed portion can be performed smoothly, and galling can be prevented from occurring on the press-fit hole inner circumferential surface. do not have.

[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 as a press-fit part, ball bearing, 3...Press-fit hole, 6...Deformed part, 6a-Tapered outer peripheral surface, γ...Crimp part, E, 1 discharge... Engine as a press-fitted member, bearing boulder, θ...tilt (angle patent) Applicant: Honda Motor Co., Ltd., Figure 5, Figure 3 [4, Figure 7, Figure 6]

Claims (1)

[Claims] This is a press-fit part that 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 part that expands the diameter of the press-fit hole; a crimp part that is connected to a large diameter end of the deformed part and has a circular cross section that tightly fits into the press-fit hole after the diameter has been expanded; The inclination angle of the tapered outer circumferential surface of the deformed portion is 3° or more and 12°
A press-fit part characterized by the following settings.