JP2003042136A - End piece pressure welding type hollow camshaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the reduction of connecting strength between an end piece and a hollow shaft in an end piece pressure welding type hollow camshaft. SOLUTION: In the end piece pressure-welding type hollow camshaft pressure- welded with an end piece 1 at least at one end of the hollow shaft 2, an outer diameter of an end face 5 of a pressure-welding portion 3 of the end piece 1 kept in press-contact with the hollow shaft 2 is the same as an outer diameter of an end face 6 of the hollow shaft 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an end piece pressure contact type hollow camshaft.

[0002]

2. Description of the Related Art An end piece pressure contact type hollow cam shaft in which an end piece is fixed to a hollow shaft by a friction pressure welding method is known from Japanese Patent Laid-Open No. 2000-213551. In this end piece press contact type hollow cam shaft, the press contact portion is located on the same end surface as the end surface of the end piece on the hollow shaft side.

[0003]

When the heat capacity of the end piece side pressure contact portion is larger than the heat capacity of the hollow shaft side pressure contact portion, the end piece pressure contact type hollow cam shaft loses heat balance during the pressure contact and has a small heat capacity. There is a case where only the shaft side is heated to the bonding temperature, and the pressure welding process ends before the end piece side having a large heat capacity reaches the predetermined bonding temperature. In this case, since the structure and hardness change abruptly at both joint interfaces, residual stress is likely to occur, stress concentration is likely to occur during operation of the camshaft, and the joint strength is reduced.

The present invention has been made in order to solve this problem, and an object thereof is to prevent deterioration of the shaft strength of the joint portion in the end piece pressure contact type hollow cam shaft.

[0005]

In order to solve the above-mentioned problems, the means adopted by the present invention is, in an end-piece pressure contact type hollow camshaft, for joining the end face of the pressure-contact portion and the hollow shaft for joining to the hollow shaft of the end piece. The difference is that the outer diameters of the end faces are the same and the difference in heat capacity between the two pressure contact portions is small. Preferably, the end surface of the press-contact portion of the end piece and the end surface of the hollow shaft have the same shape and size, and the heat capacities of both press-contact portions are the same. More preferably, in order to prevent the maximum stress from occurring in the joint portion, the pressure contact portion is hollow at a certain distance or more from the end surface of the end piece on the hollow shaft side, for example, 1 mm or more, preferably 3 mm or more, more preferably 6 mm or more Make it project to the shaft side.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described based on the embodiments shown in the drawings.

FIG. 1 is a side sectional view of an end piece pressure contact type hollow cam shaft of the first embodiment, (a) showing a state before joining and (b) showing a state after joining.

As shown in FIG. 1 (a), the end piece 1
The pressure contact portion 3 joined to the hollow shaft 2 is a cylindrical body, and its end surface 5 is located on the same end surface as the hollow shaft side end surface 4 of the end piece 1. The end surface 5 of the press contact portion 3 has a solid circular shape, and the outer diameter thereof is the same as the outer diameter of the hollow circular end surface 6 of the hollow shaft 2. An annular groove 7 is engraved around the press contact portion 3. The inner diameter of the annular groove 7 is equal to the outer diameter of the end face 5 of the press contact portion.

As shown in FIG. 1B, the end piece 1
Is rotated, and the end surface 6 of the hollow shaft 2 is fixedly contacted with the end surface 5 of the pressure contact portion 3 to apply frictional pressure to generate frictional heat. When the end faces are brought into a state suitable for pressure contact due to frictional heat, the rotation of the end piece 1 is suddenly stopped, and a large upset thrust force is applied in the axial direction to complete the pressure contact.

At this time, a burr having no warp is formed on the outer peripheral side of the pressure contact portion of the end piece 1 and the hollow shaft 2, and a burr having a warp is formed on the inner peripheral side. Although there is no danger of burrs without warpage falling off, burrs with warping may fall off.Therefore, when using the hollow part inside the camshaft as an oil passage, it is not shown.
From a sealing portion having substantially the same shape as the inner shape of the hollow shaft, and a connecting portion for connecting the sealing portion and the center of the end face of the pressure contact portion to form a confined space between the inner peripheral surface of the hollow shaft. The confinement member is provided in the press contact portion, and the burr that has fallen off from the inner peripheral side of the press contact portion is confined in the hollow shaft.

The heat capacity of the pressure contact portion between the end piece 1 and the hollow shaft 2 is slightly larger on the end piece side than on the hollow shaft side.
Since the difference is relatively small, both the end surface 5 of the end piece pressing portion 3 and the end surface 6 of the hollow shaft 2 reach a predetermined joining temperature and come into pressure contact with each other. Therefore, there is no abrupt change in structure or change in hardness at both joint interfaces, so that the end piece 1 and the hollow shaft 2 are well joined and always maintain sufficient joint strength.

[0012]

Next, another embodiment of the present invention will be described.

2A and 2B are side sectional views of an end piece press contact type camshaft according to the second embodiment. FIG. 2A shows a state before joining and FIG. 2B shows a state after joining.

As shown in FIG. 2A, the end piece 1
The pressure contact portion 3a joined to the hollow shaft 2a of a is a cylindrical body
The end surface 5a is located on the same end surface as the hollow shaft side end surface 4a of the end piece 1a. The end surface 5a of the press contact portion 3a is a hollow circle having the same shape and size as the hollow circular end surface 6a of the hollow shaft 2a. An annular groove 7a is engraved around the press contact portion 3a.
The inner diameter of the annular groove 7a is equal to the outer diameter of the end face 5a of the pressure contact portion.

As shown in FIG. 2B, the end piece 1
By rotating a, the end surface 6a of the hollow shaft 2a is fixedly contacted with the end surface 5a of the press contact portion 3a, and frictional pressure is applied to generate frictional heat. When the end faces are brought into a state suitable for pressure contact due to frictional heat, the rotation of the end piece 1a is abruptly stopped, and an upset thrust force is applied in the axial direction for pressure contact.

At this time, the end piece 1a and the hollow shaft 2a
Burrs that do not warp are formed on the outer peripheral side and the inner peripheral side of the pressure-contacting portion. Since this burr does not fall off,
Even when the hollow portion inside the camshaft is used as an oil passage, it is not necessary to provide a confinement member at the pressure contact portion of the end piece.

The end piece 1a and the hollow shaft 2 of the second embodiment.
Since the pressure contact portion of a has the same shape and the same size and the same heat capacity, both end surfaces 5a and 6a always reach the predetermined bonding temperature at the same time and are pressure bonded. Therefore, since there is no sudden change in structure or change in hardness at the joining interface between the two, the joining between the end piece 1a and the hollow shaft 2a is good and always maintains sufficient joining strength.

3A and 3B are side sectional views of an end piece pressure contact type camshaft of the third embodiment. FIG. 3A shows a state before joining and FIG. 3B shows a state after joining.

As shown in FIG. 3A, the end piece 1
The pressure contact portion 3b joined to the hollow shaft 2b of b is 1 mm or more, preferably 3 mm from the hollow shaft side end surface 4b of the end piece 1b.
It is a columnar body projecting toward the hollow shaft side of at least 6 mm, more preferably at least 6 mm. The end surface 5b of the press contact portion 3b has a solid circular shape, and the outer diameter thereof is the same as the outer diameter of the hollow circular end surface 6b of the hollow shaft 2b.

As shown in FIG. 3B, the end piece 1
By rotating b, the end surface 5b of the press contact portion 3b is fixedly contacted with the end surface 6b of the hollow shaft 2b to apply frictional pressure to generate frictional heat. When the end faces are brought into a state suitable for pressure contact due to frictional heat, the rotation of the end piece 1 is suddenly stopped, and a large upset thrust force is applied in the axial direction to complete the pressure contact.

By projecting the pressure contact portion from the end surface of the end piece on the hollow shaft side toward the hollow shaft side, it is possible to avoid stress concentration at the joint portion and to strengthen the joint strength of the hollow camshaft.

At this time, the end piece 1b and the hollow shaft 2b
A burr having no warp is formed on the outer peripheral side of the pressure contact portion and a burr having a warp is formed on the inner peripheral side. Although there is no risk of burrs without warpage falling off, burrs with warping may fall off.Therefore, when using the hollow part inside the camshaft as an oil path, it is not shown in the figure but inside the hollow shaft. A sealing portion having substantially the same shape as the shape,
A confinement member consisting of the sealing part and the connecting part that connects the center of the end face of the press contact part to form a space confined between the inner peripheral surface of the hollow shaft is provided in the press contact part, and is dropped from the inner peripheral side of the press contact part. The burrs are trapped inside the hollow shaft.

The heat capacity of the pressure contact portion between the end piece 1b and the hollow shaft 2b is slightly larger on the end piece side than on the hollow shaft side, but the difference is relatively small, so the end piece pressure contact portion 3
Both the end surface 5b of b and the end surface 6b of the hollow shaft 2b reach a predetermined joining temperature and are brought into pressure contact with each other. Therefore, since there is no sudden change in structure or change in hardness at the joining interface between the two, the joining between the end piece 1b and the hollow shaft 2b is good and always holds sufficient joining strength.

4A and 4B are side sectional views of an end piece pressure contact type camshaft of a fourth embodiment. FIG. 4A shows a state before joining and FIG. 4B shows a state after joining.

As shown in FIG. 4A, the end piece 1
The pressure contact portion 3c joined to the hollow shaft 2c of c is a cylindrical body projecting from the hollow shaft side end surface 4c of the end piece 1c to the hollow shaft side by 3 mm or more. The hollow circular end surface 5c of the press contact portion 3c has the same shape and size as the hollow circular end surface 6c of the hollow shaft 2c.

As shown in FIG. 4B, the end piece 1
By rotating c, the end surface 6c of the hollow shaft 2c is fixedly contacted with the end surface 5c of the press contact portion 3c, frictional pressure is applied, and frictional heat is generated. When the end faces are brought into a state suitable for pressure contact due to frictional heat, rotation of the end piece 1c is suddenly stopped, and an upset thrust force is applied in the axial direction for pressure contact.

At this time, the end piece 1c and the hollow shaft 2c
Burrs that do not warp are formed on the outer peripheral side and the inner peripheral side of the pressure-contacting portion. Since this burr does not fall off,
Even when the hollow portion inside the camshaft is used as an oil passage, it is not necessary to provide a confinement member at the pressure contact portion of the end piece.

End piece 1c and hollow shaft 2 of the fourth embodiment
Since the pressure contact portion of c has the same shape and the same size and the same heat capacity, both end surfaces 5c and 6c always reach a predetermined bonding temperature at the same time for pressure contact. Therefore, since there is no sudden change in structure or change in hardness at the joining interface between the two, the joining between the end piece 1c and the hollow shaft 2c is good and always holds sufficient joining strength.

FIG. 5 is a side sectional view of the end piece pressure contact type camshaft of the fifth embodiment after joining. Similar to the above embodiment, the end surface 5d of the press contact portion 3d and the end surface 6d of the hollow shaft 2d have the same shape and size. The press contact portion 3d has an end piece 1d at the center.
The hollow shaft side end surface 4d has a recessed portion 8d that is deeply recessed on the axial outer end side. The inner diameter of the recess 8d is the same as the inner diameter of the hollow shaft 2d.

Such a recess can be applied to the second embodiment shown in FIG.

The configuration and effects of the fifth embodiment other than those described above are exactly the same as those of the fourth embodiment.

[0032]

As described above, in the conventional end piece pressure contact type hollow cam shaft, there is a great difference in heat capacity between the pressure contact portions of the end piece and the hollow shaft, so there is a concern that the joint strength may be reduced. The piece press-contact type hollow cam shaft has an excellent effect that there is no possibility of deterioration of the joint strength because there is no difference in the heat capacities of the end piece and the press contact portion of the hollow shaft, or there is a slight difference.

When the press contact portion projects from the end face of the end piece on the hollow shaft side toward the hollow shaft side by 1 mm or more, stress concentration at the joint can be avoided.

[Brief description of drawings]

FIG. 1 is a side sectional view of an end piece pressure contact type camshaft according to a first embodiment of the present invention, in which (a) shows a state before joining,
(B) shows the state after joining, respectively.

FIG. 2 is a side sectional view of a second embodiment, (a) showing a state before joining, and (b) showing a state after joining, respectively.

FIG. 3 is a side sectional view of a third embodiment, (a) showing a state before joining and (b) showing a state after joining, respectively.

4A and 4B are side sectional views of a fourth embodiment, FIG. 4A showing a state before joining and FIG. 4B showing a state after joining.

FIG. 5 is a side sectional view showing a state after joining of the fifth embodiment,

[Explanation of symbols]

1, 1a, 1b, 1c, 1d: End pieces 2, 2a, 2b, 2c, 2d: Hollow shafts 3, 3a, 3b, 3c, 3d: Pressure contact parts 4, 4a, 4b, 4c, 4d: End faces (end pieces Hollow shaft side) 5, 5a, 5b, 5c, 5d: End face (press contact part) 6, 6a, 6b, 6c, 6d: End face (hollow shaft) 7, 7a: Annular groove 8d: Recess

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Sato             1111 Nogi, Nogi-cho, Shimotsuga-gun, Tochigi Prefecture Japan Piss             Tonling Co., Ltd. Tochigi factory (72) Inventor Yuki Yamanaka             1111 Nogi, Nogi-cho, Shimotsuga-gun, Tochigi Prefecture Japan Piss             Tonling Co., Ltd. Tochigi factory F-term (reference) 3J023 EA02 FA02 GA03                 3J033 AA01 AB03 AC01 BA02 BA07                       BA20

Claims (5)

[Claims] 1. Hollow shaft (2, 2a, 2b, 2c, 2d)
End pieces (1, 1a, 1b, 1
c, 1d) in a pressure-contacted camshaft, a pressure-contact portion (3, 3a,
3b, 3c, 3d) end faces (5, 5a, 5b, 5c, 5
The outer diameter of d) is the end surface (6, 6a, 6b, 6) of the hollow shaft.
End piece pressure contact type hollow camshaft having the same outer diameter as c, 6d). 2. The end piece press contact type hollow cam shaft according to claim 1, wherein the end faces (5a, 5c, 5d) of the press contact portions (3a, 3c, 3d) are hollow shafts (2a, 2c, 2).
An end-piece pressure contact type hollow camshaft having the same shape and size as the end faces (6a, 6c, 6d) of d). 3. The end piece press contact type hollow camshaft according to claim 1, wherein the press contact portion (3, 3a) is on the same end surface as the hollow shaft side end surface (4, 4a) of the end piece (1, 1a). And an annular groove (7,
7a) is engraved, an end piece pressure contact type hollow camshaft. 4. The end piece pressure contact type hollow cam shaft according to claim 1, wherein the pressure contact parts (3b, 3c, 3).
The end piece (1b, 1c, 1d) is an end piece pressure contact type hollow camshaft, characterized in that the end piece (1b, 1c, 1d) projects from the hollow shaft side end surface (4b, 4c, 4d) to the hollow shaft side. 5. The end piece pressure contact type hollow cam shaft according to claim 3 or 4, wherein the pressure contact portion (3d) is located at the center of the end piece (1d) at an axially outer end than the hollow shaft side end surface (4a, 4d). An end-piece pressure contact type hollow camshaft having a concave portion (8d) that is depressed toward the side.