JP4506198B2 - Bush and bushing manufacturing method - Google Patents

Description

The present invention relates to a bush formed by bending a plate-shaped material into a cylindrical shape and a method for manufacturing the bush.

Conventionally, a bush having a back metal and a bearing layer is well known, and a manufacturing method thereof is generally formed by cutting a strip-shaped material having a back metal and a bearing layer into a predetermined length to form a plate-like material. The both ends of the plate-like material are curved so as to abut each other and are formed into a cylindrical shape (for example, cited document 1, cited document 2, cited document 3).
JP 2000-283166 A JP-A 64-69819 JP-A-57-72773

Conventionally, when the strip material is cut into a predetermined length, the strip material is linearly cut in a direction perpendicular to the longitudinal direction of the strip material. As a result, when both ends of the plate-like material obtained by the above-mentioned cutting are brought into contact with each other to be curved and formed into a cylindrical shape, first, either one side in the width direction of both ends, that is, one corner of the plate-like material. After the parts come into contact with each other, the whole area of both end parts may be molded so as to be in close contact with each other toward the other corner part.
In this case, when the deformation of the corner portion that is contacted first increases, the risk of cracks occurring between the back metal and the bearing layer increases, particularly in the corner portion. This tendency is particularly prominent when the bearing layer is a synthetic resin-based bearing layer having a small plastic deformation capacity with respect to the back metal, and the defect rate may reach 20 to 30% in the mass production process.
Conventionally, when a plate-shaped material is curved and formed into a cylindrical shape, there is a problem that the axial center portion of the outer peripheral surface of the bush tends to be a concave shape slightly recessed from both ends, and the straightness of the back surface of the bush is poor. It was.
In view of such circumstances, the present invention can reduce the risk of cracking between the back metal and the bearing layer, and can produce a bush and a bush that can improve the straightness of the back surface of the bush . A method is provided.

That is, the invention of claim 1 forms a plate-like material by cutting a strip-like material provided with a back metal and a bearing layer into a predetermined length, and then curves both ends of the plate-like material so as to abut each other. In the method of manufacturing a bush that is molded into a cylindrical shape,
A widthwise central portion of at least one end portion of the plate-shaped material is formed so as to protrude , and the end portion is formed in a direction perpendicular to the longitudinal direction of the strip-shaped material, and the tip surface It is formed in a trapezoidal shape with an inclined surface cut linearly obliquely rearward from the both sides in the protruding direction, and then curved so that both ends of the plate-like material abut each other and formed into a cylindrical shape . It is characterized by this.
The invention of claim 5 is a bush formed into a cylindrical shape by curving so that both end portions of a plate-like material provided with a back metal and a bearing layer face each other.
At least one end portion of the plate-like material has a front end surface formed in a direction perpendicular to the projecting direction with a center portion in the width direction projecting from the end portion, and the projecting direction from both sides of the front end surface. Thus, it is formed in a trapezoidal shape by an inclined surface that is cut obliquely rearward and linearly.

According to the first aspect of the present invention , the first contact is always the projecting portion of the central portion in the width direction, so that the risk of cracking between the back metal and the bearing layer is reduced compared to the corner portion. Can do.
In addition, since the dimension in the length direction at the center part in the width direction of the plate-like material is longer than the dimension in the length direction on both sides in the width direction, the center part in the axial direction on the outer peripheral surface of the bush is slightly recessed from both ends. It is possible to suppress the formation of a bowl shape, thereby making it possible to improve the straightness of the back surface of the bush.
Therefore, according to the fifth aspect of the present invention, it is possible to provide a bush having a low risk of cracking between the back metal and the bearing layer and having a good straightness.

  The manufacturing method of the present invention will be described below with reference to the illustrated embodiment. In FIG. 1, a strip-shaped material 1 having a back metal and a bearing layer is cut to a required length to form a plate-shaped material 2. When the plate-like material 2 is cut, a scrap 3 is formed between the belt-like material 1 and the plate-like material 2, with the center portion in the width direction of the belt-like material 1 being narrowed to form the scrap 3. While the plate-like material 2 is sequentially cut from the belt-like material 1, the widthwise central portions at both end portions 4 of the plate-like material 1 are projected.

In the illustrated embodiment, each of the end portions 4 is linearly cut obliquely rearward from the front end surface 4A formed in a direction orthogonal to the longitudinal direction of the strip-shaped material 1 and the protruding direction from both sides of the front end surface 4A. Each of the inclined surfaces 4B and 4B has a trapezoidal shape.
At this time, each inclined surface 4B is preferably formed in the range of the width direction dimension W1 of 1/10 or more with respect to the entire width direction dimension W, and the direction orthogonal to the longitudinal direction of the strip-shaped material 1 is used as a reference. The angle θ of the inclined surface is preferably set in the range of 2 to 6 °. Furthermore, it is desirable to slightly chamfer the corner portion between the inclined surface 4B and the side surface of the plate material 2.

  After the plate-like material 2 is cut and formed from the strip-like material 1 as described above, the two end portions 4 and 4 of the plate-like material 2 are then bent so as to abut each other and formed into a cylindrical shape. The plate-shaped material 2 may be formed into a cylindrical shape by a conventionally known method. For example, the plate-shaped material 2 can be formed into a cylindrical shape by a two-divided mold.

Next, the function and effect of the present invention will be described based on experimental results.
First, as the band-shaped material, a band-shaped material 1 in which a back plate of a steel plate and a bearing layer mainly composed of a resin and graphite were adhered to each other was used. The bearing layer may be made of a copper alloy, an aluminum alloy, or a resin material in which a porous sintered layer is impregnated with a resin and a soft metal.
As the product 1 of the present invention, the width W of the plate-shaped material 2 cut out from the band-shaped material 1 is 27 mm, and the length dimension L in the center portion in the width direction at both ends is 55.1 mm. Both end portions were each formed in a trapezoidal shape, the dimension W1 in the width direction of each inclined surface 4B was set to 3 mm which is 1/10 or more of the width W, and the angle θ was set to 3 °. Further, the corners between the inclined surfaces 4B and the side surfaces of the plate material 2 were chamfered with an arc having a radius of 0.8 mm.

Moreover, as this invention product 2, the width W of the plate-shaped raw material 2 cut out from the said strip-shaped raw material 1 shall be 12.2 mm, and the dimension L of the length direction in the center part of the width direction of both ends is 55.1 mm. Both end portions were formed in a trapezoidal shape, the width direction dimension W1 of each inclined surface 4B was set to 1.5 mm which is 1/10 or more of the width W, and the angle θ was set to 3 °. This plate material was also chamfered as described above.
Furthermore, as a comparative example, the strip-shaped material 1 was cut linearly in a direction perpendicular to the longitudinal direction to produce a plate-shaped material 2. The width W of this plate-shaped material was 27 mm, and the dimension L in the length direction was 55.1 mm. This comparative example is also chamfered as described above.
Then, the invention products 1 and 2 and the comparative example were each bent under the same conditions so that the bearing layer was inside by means of a mold (not shown) that was divided into two to produce cylindrical bushes.

FIG. 2 is a diagram showing the rate of occurrence of cracks, and FIG. 3 is a diagram showing the amount of saddle warp on the back of the bush.
As can be seen from FIG. 2, the comparative example has a defect rate of 12 to 32%, whereas the present product 2 can be 3% or less, and the present product 1 should be almost zero. I was able to.
In addition, as can be seen from FIG. 3, the amount of saddle warp on the back surface of the bush in the comparative example is as large as 70 to 90 μm, whereas in the product 1 of the present invention, it can be as small as 10 to 20 μm. It was able to be good.

The top view explaining the manufacturing method of this invention. The experimental result figure which showed the incidence rate of a crack. The experimental result figure which showed the amount of bowl-shaped warpage of a bush back.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Band-shaped material 2 Plate-shaped material 4 End part 4A tip surface 4B inclined surface W Width direction dimension of plate-shaped material 2 W1 Width direction dimension of inclined surface 4B θ Angle of inclined surface 4B

Claims (5)

A bush material that is formed by cutting a strip-shaped material having a backing metal and a bearing layer into a predetermined length to form a plate-shaped material, and then bending the both ends of the plate-shaped material so as to abut each other. In the manufacturing method,
A widthwise central portion of at least one end portion of the plate-shaped material is formed so as to protrude , and the end portion is formed in a direction perpendicular to the longitudinal direction of the strip-shaped material, and the tip surface It is formed in a trapezoidal shape with an inclined surface cut linearly obliquely rearward from the both sides in the protruding direction, and then curved so that both ends of the plate-like material abut each other and formed into a cylindrical shape . A bushing manufacturing method characterized by the above. 2. The method for manufacturing a bush according to claim 1 , wherein a dimension in the width direction of each of the inclined surfaces is 1/10 or more of a whole dimension in the width direction. 3. The method for manufacturing a bush according to claim 1 , wherein an angle of the inclined surface with respect to a direction orthogonal to the longitudinal direction of the strip-shaped material is in a range of 2 to 6 °. The bearing layer may bushing method according to any one of claims 1 to claim 3, characterized in that a bearing layer of synthetic resin.   In the bush formed by bending the both ends of the plate-like material provided with the back metal and the bearing layer so as to face each other,
  At least one end portion of the plate-like material has a front end surface formed in a direction perpendicular to the projecting direction with a center portion in the width direction protruding from the end portion, and the projecting direction from both sides of the front end surface The bush is formed in a trapezoidal shape by an inclined surface cut linearly and obliquely rearward.

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