JPH0510533B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <<Industrial Application Field>> The present invention relates to a method of manufacturing a bushing mainly for a vehicle, which is used for connecting and attaching a vibrating member in a suspension part, an engine mount part, etc. of an automobile.

<<Background of the Invention>> A bushing used for purposes such as vibration isolation and cushioning generally consists of a cylindrical outer member, a shaft inserted inside the bushing, and a space between the outer member and the shaft. The outer member is fixed to a swinging member such as an automobile suspension arm, and the joint surfaces at both ends of the shaft are pressed against the other connecting member and fastened with bolts, nuts, etc. By doing so, the relative movement of the swinging member and the connecting member is buffered, and an elastic connection with a degree of freedom in directionality in swinging is achieved.

In such a device, if the joint surface of the shaft is smooth, when excessive torque is applied to the shaft due to the movement of the swinging member, slippage may occur between the joint surface of the shaft and the connecting member, resulting in the connection being difficult. Looseness occurs in the parts. For this reason, it is necessary to provide a locking mechanism on the joint surface of the shaft. As a means to prevent this loosening,
It is possible to consider methods in which the joint surface of the shaft is subjected to shot processing such as sandblasting, or in which serrated teeth or pawls are formed by knurling or press cutting (for example, Utility Model No. 57-65245).
No. 57-165827).

In the case of shot processing, it is difficult to mask the rubber, so first, shot processing is performed on the shaft.
After that, it is common to bake the rubber. However, the rough surface resulting from shot processing may be crushed and smoothed by the clamping of the mold during the rubber baking process, or may be smoothed together when the rubber adhering to the surface is removed by buffing etc. after baking. I end up.
Therefore, it is difficult to be an effective means for preventing loosening.

In the case of teeth or claws, the teeth or claws are prevented from loosening by deeply digging the serrated teeth formed at the end of the shaft or the tip of the claw into the contact surface of the connecting member. It is required to be large and harder than the connecting member, and is usually hardened. However, there is a problem in that the number of man-hours required for this process is extremely large.

<<Objective of the Invention>> The object of the present application is to provide a surface that is not easily smoothed like a rough surface by shot processing, and is not so hard that it bites into the contact surface of a connecting member like a hardened tooth or pawl. To provide a method for manufacturing a bushing that can form a loosening preventer of appropriate hardness on the joint surface of a shaft.

<<Means for Solving the Problems>> The manufacturing method of the bush according to the present application involves inserting a shaft into the hollow part of a cylindrical outer member, causing the end of the shaft to protrude outward from the outer member, and forming the protruding end. A joint surface for fastening with the connecting member is provided on the part, rubber is filled between the shaft and the outer member to connect and integrate the outer member and the shaft, and then a mold with a molded protrusion formed on the surface is attached to the shaft. By stamping on the joining surface, a recess corresponding to the molded protrusion is carved on the joining surface, and as the recess is formed, a burr is formed that protrudes from the periphery of the recess in the joining direction. shall be.

<Operation of the Invention> According to the method of the present invention, when rubber is baked, since no recesses are formed on the joint surface of the shaft and it is smooth, adhesive and rubber attached to the surface can be easily removed. It is possible. Thereafter, when the joint surface of the shaft is stamped with a mold having a molding protrusion formed on the surface, a recess corresponding to the molding projection of the mold is formed on the joint surface of the shaft, and
A burr is integrally formed around this recessed portion in the joining direction, and a rough surface that prevents loosening is formed on the joining surface. Furthermore, this rough surface is not affected by the rubber baking process and is reliably formed on the finished bush.

<<Example>> First, a press-fit bushing used in an automobile suspension part manufactured according to this example is shown in FIGS. 1 to 4. As shown in FIGS. 1 and 2, this bush 1 includes an outer member 2 which is a metal cylinder, a shaft 3 inserted into the outer member 2, and a shaft 3 filled between the outer member 2 and the shaft 3. It consists of rubber 4. The outer member 2 and the shaft 3 are cylindrical metal shaft members. The hollow part of the shaft 3 is a mounting hole 5 for passing mounting members such as bolts.
Further, both ends form projecting end portions 6 extending outwardly from the outer member 2, and these end surfaces serve as joint surfaces 6a with a connecting member to be described later.

The joint surface 6a is roughened to include a large number of recesses 7 and burrs 8 (FIG. 1) formed around the recesses. The recess 7 has a substantially triangular cross section carved inward from the joining surface 6a, and a burr 8 is integrally formed around it in the joining direction (the direction of joining with the connecting member, the top and bottom in FIG. 1). direction) normally
It is raised and protruded by about 0.04 to several mm. The burr 8 is buckled and crushed when the shaft 3 and the connecting member are strongly connected by bolting or the like, but it is not completely smoothed and has a rough surface on the joint surface 6a. It is something.

The rubber 4 includes a bridge portion 9 that connects the outer member 2 and the shaft 3, and a clearance portion 10 (a second
) are formed in the axial direction, respectively. However, the presence or absence of the clearance portion 10 can be freely determined as necessary.

3 and 4 show the state of use. first,
As shown in FIG. 3, the bush 1 includes a swinging member 11 such as a training arm in the suspension section.
The connecting member 1 fixed to the vehicle body is press-fitted into a holder 12 formed at the end of the bushing 1 and having a diameter slightly smaller than the outer diameter of the bushing 1.
Mounting holes 14, 1 formed in the connecting members 13, 15 in contact with the side portions 13a, 15a of the connecting members 13, 15.
6 and the mounting hole 5 are aligned and fastened with fasteners such as bolts 17 and nuts 18. Figure 4 shows the state after fastening.

Next, an example of the manufacturing method of this bush will be explained with reference to FIGS. 5 to 8.

FIG. 5 shows the mold in the rubber baking process. The outer member 2 and the shaft 3 are fixed between the upper mold 20, the middle mold 21, and the lower mold 22, and the shaft 3 protrudes downward and upward from the upper mold 20 and the lower mold 22, respectively, into the mounting hole 5. Guides 23 and 24 are inserted and positioned. A cavity 25 formed between the outer member 2 and the shaft 3 is a space filled with rubber, and a rubber liquid is press-injected into the cavity through an injection hole 26 and vulcanized. Note that at this time, the joint surface 6a of the shaft 3 has not been processed yet and remains a smooth surface. FIG. 6 shows an intermediate molded product 27 formed by this mold. This differs from the final molded product (bush 1) only in that, as described above, the joint surface 6a of the shaft 3 remains an unfinished smooth surface. Therefore, this intermediate molded product 27
is fixed to a suitable jig of the press molding machine, and the joint surface 6
With respect to a, a mold having a large number of protruding protrusions 31 formed on the base plate 30 is pressed through a shaft 32 by applying pressure. Then, as shown in FIG. 8, a recess 7 corresponding to the molded protrusion 31 is stamped on the joint surface 6a. At the same time, a burr 8 is formed around the recess 7 integrally and raised toward the surface. In addition,
When pressing the joint surfaces 6a, 6a at both ends,
It is best to do both at the same time. As a result, a bush 1, which is the final molded product of the present invention, is obtained.

Next, the use of the bush 1 thus obtained will be explained. In the fastened state shown in FIG. 4, the burr 8 on the joint surface 6a protrudes in the joining direction, and since it has not been hardened, it is buckled and deformed by the pressure caused by the fastening and is crushed. However, since crushed burrs remain on the joint surface, it is not completely smoothed and remains rough. That is, the burr 8 has a buckling property and is not completely smoothed during fastening. As a result, the contact surface 13a between the shaft 3 and the connecting members 13, 15,
15a becomes large, and the relative slippage on this surface is suppressed to prevent the fastening portion from loosening.
Moreover, since it has no directionality, it is still effective against rotation. Moreover, since the contact surfaces 13a, 15a of the connecting members 13, 15 are not easily damaged by the easy buckling deformation of the burr 8, deep digging by the burr 8 is not formed on the connecting members 13, 15 side. Therefore, when replacing the bush 1 with a new one, the burr 8 is attached to the connecting members 13 and 15.
It can be fastened immediately at any position relative to the contact surfaces 13a, 15a. That is,
If a bite mark remains as in the conventional case, loosening may occur during use unless the new tooth tip is tightened with the tip of the new tooth aligned with the bite mark. However, according to this embodiment, this is impossible. Close alignment work becomes unnecessary. Therefore, the bush 1 can be replaced easily and quickly, and maintainability is significantly improved. Moreover, since the burr 8 is not hardened and is essentially a hard material, the connecting members 13, 15
This makes it possible to combine materials of the same degree of hardness, that is, similar materials, for the shaft 3 and the shaft 3, increasing the degree of freedom in material selection.

FIG. 9 is a graph of the characteristics when the bush 1 is fastened, and is a characteristic diagram when a torque detector is attached to the connecting member 13 or 15 and the outer member 2 is rotated. This graph shows the rotation angle on the horizontal axis and the torque on the vertical axis, and shows how much torque the fastening part can withstand without slipping.Slippage occurs when the characteristic curve becomes parallel to the horizontal axis. Further, the solid line in the graph is for the present example, and the dotted line is for the comparative example subjected to sandblasting. As is clear from this, the structure of this embodiment can withstand large torque and suppress slippage.

As described above, according to this embodiment, when the joint surfaces at both ends of the shaft are roughened using a shot method such as sandblasting or steel blasting after the rubber is baked, the outer members and the rubber must be masked. However, even after the rubber baking process, the joint surface 6
It is possible to easily form a burr 8 above a to a certain degree of effectiveness as a loosening preventer.

In addition, even if an attempt was made to perform end face processing on a cylindrical object by knurling or the like on the joint surface 6a of the cylindrical shaft 3 as in this embodiment, there is currently no tool that can be applied immediately, and a special dedicated machine would have to be developed. Must. Furthermore, if it is done by hand, the machined surface tends to be an irregularly curved surface,
Fasteners tend to loosen. The same is true for other machining processes, which either require the development of special techniques or are extremely inefficient. However, the molded protrusion 31 as in this embodiment
By using a mold equipped with this, practical and efficient manufacturing with high mass productivity is possible without the need for a special dedicated machine.

Note that the present invention can be applied in various ways, and the dimensions of the burr can be adjusted as appropriate depending on the fastening conditions. When forming a burr on the end surface of the shaft, it may be formed on only one side instead of both sides.

Furthermore, the bush obtained by the present invention can be used not only in suspension parts and engine mount parts, but also in various places that require vibration isolation, elastic coupling, and the like.

<<Effects of the Invention>> According to the method of the present invention, burrs are formed by roughening the surface by press molding, etc., so burrs can be formed after baking the rubber and removing the attached rubber, etc. I can do it. Therefore, the joint surface of the shaft in the manufactured bushing can maintain a predetermined rough surface even though the rubber is baked and the adhering rubber is sufficiently removed. Moreover, since the process of removing adhered rubber and the like becomes easy and quick, products of constant quality can be manufactured at low cost.

[Brief explanation of the drawing]

1 to 9 show an embodiment of the present invention, FIG. 1 is a cross-sectional view of the bushing taken along the line shown in FIG. Figure 4 is an axial sectional view of the installed state, Figure 5
The figure is a cross-sectional view showing rubber baking molding, Figure 6 is a cross-sectional view of an intermediate product, Figure 7 is a partial cross-sectional view showing the roughening method, and Figure 8 is an enlarged cross-sectional view of the molded surface after roughening. , FIG. 9 is a graph showing the characteristics of the bush with respect to torque. Explanation of symbols, 1...Button, 2...Outer member, 3...Shaft, 4...Rubber, 6...End face,
7... recess, 8... burr, 12... rocking member, 1
3... Connecting member, 15... Connecting member, 27... Intermediate product.

Claims (1)

[Claims] 1. Insert the shaft into the hollow part of the cylindrical outer member, make the end of the shaft protrude outward from the outer member, provide the protruding end with a joint surface when fastening with the connecting member, and connect the shaft and the outer member. Rubber is filled between the members to connect and integrate the outer member and the shaft,
Next, by stamping the joint surface of the shaft with a die having molded projections formed on the surface, a recess corresponding to the molded projection is carved on the joint surface, and as the recess is formed, a recess is formed. A method for manufacturing bushings that is characterized by forming a burr that protrudes from the periphery in the joining direction.