JP3138341B2 - Radial corrugated spacer expander - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radial corrugated spacer expander, and more particularly, to a radial corrugated spacer expander for minimizing breakage of an abutment portion of the expander.

[0002]

2. Description of the Related Art A radial corrugated spacer expander is an example of a spacer expander used in combination with a side rail as an oil ring of an internal combustion engine. FIG.
Indicates the vicinity of the opening of the spacer expander 101. The spacer expander 101 has peaks 102 and valleys 103 alternately in the ring radial direction.
Except for the top portion 02 and the bottom portion of the valley portion 103, an oil passage hole 104 having the same shape is formed in the circumferential direction. Each valley is provided with a pair of ears 105 protruding in opposite directions in the axial direction, and abutments 106a, 106b extending in the radial direction for attachment to a piston (not shown) are formed at both ends. ing. The abutments 106a and 106b are formed at the corners 1 of the valley 103 at both ends of the spacer expander.
It is constituted by rising portions from 07a and 107b. And the butting surfaces 110a, 110 of the abutment portion
It forms an annular shape by abutment between b. In addition, wire 1 of predetermined length
08 is inserted through the oil passage hole 104, and when the spacer expander is mounted on the piston, the butting surfaces 110a, 1a
The contact between 10b is ensured.

[0003]

Here, with the recent demand for downsizing and high output of the internal combustion engine, a high load also acts on the combined oil ring, and the conventional radial corrugated spacer expander 101 is fitted. The corners 107a and 107b of the mouths 106a and 106b are frequently broken. If the abutments 106a and 106b are broken, the desired elasticity of the spacer expander 101 cannot be obtained, and not only the necessary oil scraping effect of the side rails is reduced, but also the abutment is released and slides. This will have a negative effect on the surface. It is therefore an object of the present invention to provide a radial corrugated spacer expander that minimizes the possibility of breakage of the abutment.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention has a structure in which a ridge and a valley are alternately arranged in a radial direction, and an oil passage hole is formed in a circumferential direction. A pair of ears protruding in the axial direction are provided, and abutments extending in the radial direction for attachment to the piston are formed at both ends. The oil hole, the ear portion is a radial corrugated spacer expander formed by punching a metal band in the thickness direction thereof,
The abutting portion is provided so that rising portions or falling portions of the both end portions can be brought into contact with each other due to elastic deformation of the metal band, and a corner portion for forming the rising portion or the falling portion is formed with a thick wall. When viewed in the direction, the present invention provides a radially corrugated spacer expander in which the barbed portion and the barbed portion on the shearing cut surface of the punching process are located on the tension side and the compression side, respectively.

[0005]

According to the radial wavy spacer expander of the present invention having the above structure, the drooping portion is located on the pulling side,
The burr is located on the compression side. That is, on the side receiving a tensile stress at the corner, for example, in the case of an abutting portion formed to rise from a valley portion, in the case of a thick inner peripheral side of the spacer expander, and in the case of an abutting portion formed to fall from a mountain portion. , Place the drooping part on the outer peripheral side of the thickness of the spacer expander,
On the side receiving the compressive stress at the corner, for example, in the case of an abutting portion formed to rise from a valley portion, to the outer peripheral wall thickness of the spacer expander, and in the case of an abutting portion formed to fall from a mountain portion, a spacer. Position the burrs on the inner peripheral side of the expander wall thickness. As a result, no tensile stress acts on the burrs, which are inferior in toughness as compared with the drooping parts, so that breakage at the corners of the abutment is minimized.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a side view showing the vicinity of an abutment portion of a radial corrugated spacer expander 1 according to a first embodiment of the present invention. As in FIG. 6, the spacer expander 1 has peaks 2 and valleys 3 alternately in the ring radial direction, and is circumferentially identical except for the tops of the ridges 2 and the bottoms of the valleys 3. An oil passage hole 4 having a shape is formed. Each valley is provided with a pair of ears 5 protruding in opposite directions in the axial direction, and abutments 6a and 6b are formed at both ends extending in the radial direction for attachment to a piston (not shown). ing. This contact 6
Reference numerals a and 6b denote the falling edges of the ridge 2 from the corners 7a and 7b at both ends of the spacer expander. And the butting surfaces 10a, 10
It forms an annular shape by abutment between b. In addition, the wire 8 of a predetermined length
When the spacer expander is mounted on the piston, the abutting surfaces 10a and 10b are in contact with each other.

FIG. 2 is a plan view showing a punched portion in a punching step in the manufacture of the spacer expander 1. In FIG. 2, a steel strip 1 </ b> A is stamped with a side edge stamped portion X for forming an ear portion 5 and a center stamped portion Y for forming an oil passage hole 4. Thereafter, the corrugated continuous bending is performed, and the radial corrugated spacer expander 1 is manufactured. Here, as shown in FIGS. 3A and 3B, when viewed from the shearing cut surface of the punching process,
The dripping portion 1a is a portion of the free surface pressed down when the tool bites into the metal strip, and a shear surface 1c, which is a glossy portion subjected to a large shear strain and burnished on the side surface of the tool, follows the portion. . Next to the shear surface 1c, there is a crystal grain surface at a portion where a crack has occurred and fractured, and there is a remarkable fracture surface 1d of fine irregularities, followed by a burr portion 1b.

In addition to the high load on the spacer expander due to the recent demand for higher engine output,
In recent years, nitriding treatment has been increasingly performed in place of chromium plating as a surface treatment of the spacer expander. This nitriding treatment increases the hardness of the spacer expander, but also increases the brittleness. It is considered that the possibility of breakage of the abutment portion has increased because the repeated stress acts about twice as much as the portion.
In view of this, the inventor of the present invention has taken into account the fact that the cracks of the punched burrs generated in the fractured surface 1d and the subsequent burrs 1b are likely to be the starting points of breakage in consideration of the specificity of the shear cut surface of the punching shearing process. Then, it was considered that the possibility of breakage of the abutment portion can be reduced by preventing the concentration of tensile stress from occurring at such a portion.

In consideration of such a shearing cut surface, in the next step of continuous wave bending, the drooping portion 1a is located on the tension side and the barb portion 1b is located on the compression side. More specifically, as shown in FIG. 4, the drooping portion 1a is located on the side of the corner portion 7a (7b) which receives a tensile stress, that is, on the outer peripheral side of the thickness of the abutting portion 6a (6b) formed from the mountain portion. The burr portion 1b is formed on the side of the corner portion where compressive stress is applied, that is, on the inner circumferential side of the thick portion of the abutment portion formed to fall from the crest portion.
Position. In other words, when the abutment portion of the spacer expander is formed by falling from the mountain portion, after punching, the barbed portion 1a is formed on the outer peripheral side of the spacer expander, and the barbed portion is formed on the inner peripheral side. What is necessary is just to perform a waveform continuous bending process so that 1b may be located. In FIG. 4, the center of the spacer expander 1 is in the direction of arrow B.

The burrs 1b are more susceptible to cracks and inferior toughness than the burrs 1a.
a (7b) is considered to be subjected to a repetitive stress twice as large as that of the other bent portions, and the above configuration prevents the burr portion from being cracked, thereby breaking at the corners of the joint. Can be minimized.

Next, a second embodiment of the radial waveform spacer expander according to the present invention will be described with reference to FIG. In contrast to the first embodiment, the second embodiment is similar to the conventional spacer expander 101 shown in FIG. 6 in that the abutment portion is formed by rising from the valley portion. It differs from the conventional spacer expander in that the cut surface is considered in the same manner as in the first embodiment. In FIG. 5, the side receiving the tensile stress at the corner 7a '(7b'), that is, the abutment 6a 'raised from the valley.
The drooping portion 1a is positioned on the inner peripheral side of the wall thickness of (6b '), and the barb is formed on the side receiving the compressive stress at the corner 7a, that is, on the outer peripheral side of the wall thickness of the abutting portion 6a' raised from the trough 3. Position the part 1b. In other words, the spacer expander 1 '
When the abutting portion 6a 'is formed by rising from the valley portion 3, after punching, the drooping portion 1a is located on the inner peripheral side of the spacer expander 1', and the barbed portion 1b is located on the outer peripheral side. What is necessary is just to perform a waveform continuous bending process so that it may be performed.

[0012]

As described above in detail, according to the radial corrugated spacer expander of the present invention, the burrs formed by punching and shearing are more susceptible to cracks and inferior in toughness than the drooping parts. It is considered that a repetitive stress twice as large as that of the other bent portions acts on the corners for forming the mouth. When the corner is viewed in the thickness direction, the drooping portion and the barbed portion of the punched shearing cut surface are located on the pulling side and the compression side of the corner, respectively, thereby breaking the joint at the corner. Can be minimized. With such a configuration, the burrs where cracks easily occur are subjected to compressive stress instead of tensile stress, so that the expansion of cracks at that point is suppressed, and the possibility of breakage of the joint at the corner is reduced. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a side view of a radial corrugated spacer expander according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a punched portion during a punching step in the manufacture of a radially corrugated spacer expander.

3A is a cross-sectional view taken along the line III-III in FIG. 2, and FIG. 3B is a side view as viewed from the direction of the arrow in FIG. 3A.

FIG. 4 is an enlarged side view showing the vicinity of an abutment portion of the radial corrugated spacer expander according to the first embodiment of the present invention.

FIG. 5 is an enlarged side view showing the vicinity of an abutment portion of a radial corrugated spacer expander according to a second embodiment of the present invention.

FIG. 6 is a perspective view showing a conventional radial wave spacer expander.

[Explanation of symbols]

 1, 1 'Radial corrugated spacer expander 1A Metal strip 1a Droop 1b Burr 2 Crest 3 Valley 4 Oil passage hole 5 Ear 6a, 6b Joint 7a, 7b Corner

Claims (1)

(57) [Claims] An oil passage is provided in the circumferential direction, having a peak portion and a valley portion alternately in a radial direction, and each valley portion is provided with a pair of ears projecting in an axial direction. Abutting portions extending in the radial direction for mounting on the piston are formed at both ends, and the abutting portions abut each other to form an annular shape. In the radial corrugated spacer expander formed by punching in the direction, the abutting portion is provided such that rising portions or falling portions of the both end portions can contact each other due to elastic deformation of the metal band, When the corners for forming the part or the falling part are viewed in the thickness direction, the drooping part and the burr part in the shearing cut surface of the punching are located on the tension side and the compression side, respectively. Radial corrugated spacer Kisupanda.