JPH03134314A - Cylindrical bush - Google Patents

Abstract

PURPOSE:To prevent decrease in the inside diameter by forming a bearing layer containing resin on a back plate, forming an axial through groove on the bearing layer, and exposing the back plate of a designated width to the bottom portion of the groove to let thermal expansion escape in the circumferential direction. CONSTITUTION:A circular bush is formed by forming a bearing layer 2 on a back plate 1, providing chamfering portions 4 on the inner periphery sides of both end portions 3, and bending the above cylindrically in such a manner that the bearing layer is put inside to meet both end portions 3 mutually. The chamfering portions 4 are made larger in such a manner as to form a through groove where the back plate 1 is exposed when both end portions 3 are joined. Further, axial through grooves 6, 7 are provided to expose the back plate 1. Resin such as PTFE, polyacetal, or the like is contained in the bearing layer. The thermal expansion of the bearing layer is let escape in the circumferential direction by the through grooves, and the inside diameter is decreased not to change the clearance with the shaft. Furthermore, the decrease in the area of a sliding surface can be prevented as much as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a cylindrical bushing, and more particularly to a cylindrical bushing with a bearing layer.

"Prior Art" Conventionally, a cylindrical bushing was formed, a bearing layer containing resin was formed on a backing metal, and the backing metal and bearing layer were curved into a circle with the bearing layer on the inside, and both ends were brought together. Things are well known.

Conventionally, through grooves have also been formed by penetrating the sliding surface of a sliding bearing on both sides in the axial direction (Utility Model No. 59
-153721).

"Problem to be Solved by the Invention" By the way, in the above-mentioned cylindrical bush, when heat is applied, the resin contained in the bearing layer thermally expands and the inner diameter decreases, thereby changing the clearance with the shaft. was.

This is because the thermal expansion coefficient of the bearing layer is larger than that of the backing metal, so that the expansion of the resin cannot escape in the circumferential direction and expands in the thickness direction.

In order to improve such defects, it is possible to form a through groove that penetrates on both sides in the axial direction in a part of the bearing layer, and to expose the back metal at the bottom of the through groove with a predetermined width in the circumferential direction. , since it is possible to release the thermal expansion of the bearing layer in the circumferential direction,
It is possible to prevent the inner diameter of the bearing layer from decreasing as much as possible.

However, on the other hand, if such a through groove is formed in the bearing layer, the area of the tank moving surface becomes smaller, resulting in a reduction in the load capacity of the bearing.

"Means for Solving the Problems" The present invention provides a method in which, in a cylindrical bush, the inner circumferential side of the end that becomes the mating part is chamfered to prevent the inner circumferential side of the end from protruding toward the shaft side. By focusing on the fact that the bearing layer is in the bearing layer and forming a through groove using that part, the thermal expansion of the bearing layer can be released in the circumferential direction while preventing the area of the sliding surface from becoming smaller as much as possible. It has been made possible to do so.

That is, the present invention provides a cylindrical bush having the above configuration,
The bearing layer at the end is removed to form a through groove penetrating both sides in the axial direction, and the back metal at the bottom of the through groove is exposed with a predetermined width in the circumferential direction.

"Operation" According to the above structure, the through groove allows thermal expansion of the bearing layer to escape in the circumferential direction, thereby preventing the inner diameter from decreasing and changing the clearance between the bearing layer and the shaft. can be prevented.

In addition to this, since the through-groove is formed at the end that is originally chamfered, the area of the sliding surface becomes smaller compared to the case where a new through-groove is formed in other parts. This can prevent the load capacity of the bearing from decreasing.

``Embodiment'' The present invention will be described below with reference to the illustrated embodiment. FIG. 1 is a plan view showing a cylindrical bush developed and FIG. 2 is a front view of FIG. And this secret money 1
The bearing layer 2 includes a resin formed thereon.

Examples of the resin for the bearing layer 2 include PTFE, polyacetal, polyimide, polyamideimide, phenol resin,
Epoxy resins, etc. can be applied, as well as lubricants such as graphite, carbon, molybdenum disulfide, and boron nitride, soft metals such as Pb, Sn, and 'Zn, and appropriate amounts of fillers such as clay, silica, alumina, and talc. It can be added to form the bearing layer 2.

Although not shown, the bearing layer 2 may be formed on a Cu sintered layer formed on the surface of the back metal 1.

Both ends of the cylindrical bushing are curved into a circle and aligned with each other so that the bearing layer 2 is on the inside, and a chamfer 4 is formed on the inner peripheral side of the end 3. Conventional chamfered portions are only slightly formed so that the inner peripheral side of the ends does not protrude toward the shaft side when both ends are brought together, but as shown in Figure 3, the chamfered portion The portion 4 is formed obliquely with respect to the circumferential direction of the backing metal 1 so that the backing metal 1 is relatively thick (exposed), leaving the end surfaces of both ends of the cylindrical bushing in contact with each other.

Therefore, as shown in FIG. 3, at the end portion 3, the bearing layer 2 is removed to form a through groove 5 penetrating both sides in the axial direction, and the back metal 1 at the bottom of the through groove S is circular. It comes to be exposed with a predetermined width W in the circumferential direction.

Furthermore, in this embodiment, as shown in FIGS. 1 and 2, in addition to the through groove 5, two through grooves 6.7 are provided in the through groove 5.
The backing metal 1 at the bottom of these through grooves 6.7 is also exposed with a predetermined width W in the circumferential direction.

According to the above configuration, the thermal expansion of the bearing layer 2 can be released in the circumferential direction by the three through grooves 5 to 7, so that it is possible to prevent the bearing layer 2 from expanding in the thickness direction. Therefore, it is possible to prevent the inner diameter from decreasing and to prevent the clearance between the bearing layer 2 and the shaft (not shown) from fluctuating.

Furthermore, since the through groove 5 is formed at the end 3 where chamfering is originally performed, the sliding surface of the bearing layer 2 is It is possible to prevent the area from becoming small as much as possible, thereby preventing the load capacity of the bearing from decreasing.

In the above embodiment, three through grooves 5 to 7 are formed, but the present invention is not limited to this, and depending on the usage conditions, only one annular groove 5 may be formed.

Also, as a cylindrical bushing with both ends butted against each other,
It may be a clinch type cylindrical bushing in which a concave portion and a convex portion formed at both ends are engaged with each other.

"Effects of the Invention" As described above, according to the present invention, by forming the through groove, fluctuations in the thickness direction of the bearing layer due to heat can be prevented as much as possible, thereby increasing the clearance between the bearing layer and the shaft. Moreover, it is possible to prevent the reduction in the area of the sliding surface due to the formation of the through groove as much as possible, thereby preventing the load capacity of the bearing from decreasing as a result. Effects can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an exploded plan view of a cylindrical bushing according to an embodiment of the present invention, FIG. 2 is a front view of FIG. 1, and FIG. 3 is an enlarged front view of a mating portion of the cylindrical bushing. 1... Back metal 3... Ends 5 to 7... Penetration groove 2... Bearing layer 4... Chamfered part

Claims (1)

[Scope of Claims] A cylindrical bushing in which a bearing layer containing resin is formed on a backing metal, the backing metal and the bearing layer are curved into a circle with the bearing layer on the inside, and both ends are brought together; 1. A cylindrical bushing, characterized in that a through-groove is formed by removing a bearing layer of a portion of the bushing, and a through-groove passing through both sides in the axial direction is formed, and a back metal at the bottom of the through-groove is exposed with a predetermined width in the circumferential direction.