JPH0735127A - Connecting rod made of resin and manufacture thereof - Google Patents

Abstract

PURPOSE:To increase the strength by arranging an elastic body on the cylindrical part made of resin of the both end parts of a rod shape part, by providing a thick part on a region in the circumferential direction of the cylindrical part, and by positioning a weld line on the thick part. CONSTITUTION:An elastic body 3 is preliminarily positioned and arranged in a cavity, and a resin material is injected from a gate A communicated to the mold space or a cylindrical part 2 in the reverse side of the cylindrical part 2 forming a thick part 4. The resin material is flowed into the mold space of the cylindrical part 2 forming the thick part 4 through the cylindrical part, and the mold space of a rod-shape part 1, and the resin material is further flowed into the resin pool of the cavity. After the entire mold space is completely filled up, the injection of the resin material is stopped. A weld line 5 is surely formed on the thick part 4 adjacent to the resin pool, while the gas sandwiched between the resin materials is purged to the resin pool, and entrainment of the gas to the chick part 4 as well as reduction in the strength caused thereby are thus prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin connecting rod which can be used as a torque rod, a stabilizer link rod, a suspension rod, etc. of an automobile engine, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A conventional connecting rod of this type is disclosed in, for example, Japanese Utility Model Laid-Open No. 50-3217. This has a tubular portion into which elastic members are fitted at both ends of a rod-shaped portion, and these tubular portion and rod-shaped portion are integrally formed by a plastic material reinforced with glass fiber. The cross section of the rod-shaped portion is such that the moments of inertia are equal in two orthogonal directions.

Such a connecting rod can be used by attaching each cylindrical portion to each connected member via an elastic member. Under the condition of use, the load is mostly both cylinders. It acts in the direction of the line segment connecting the centers of the cylindrical portions, and in particular, a large stress acts on the outermost position of the tubular portion due to the load in the tensile direction as compared with other portions.

[0004]

By the way, in the case of manufacturing such a resin connecting rod by injection molding of a resin material, if there is only one resin material injection gate, the injection gate is Even when it is positioned at a portion corresponding to either the rod-shaped portion or the tubular portion,
A weld line caused by the merging of resin materials will occur at some position in the tubular portion,
Above all, it occurs particularly often at the outermost position of the cylindrical part or in the vicinity thereof, and the mechanical strength at the part where the weld line is generated is less than half that of the other parts. In addition, when a large stress acts on the outermost position of the tubular portion, there is a problem that the connecting rod is extremely likely to be damaged from the weld line generation portion.

The present invention has been made as a result of studies to solve such problems of the prior art, and an object of the present invention is to inevitably generate a weld line in a cylindrical portion. The object is to provide a resin-made connecting rod in which damage to the connecting rod is effectively prevented by sufficiently increasing the strength of the portion where the weld line is generated, and a method for manufacturing the same.

[0006]

In the resin connecting rod of the present invention, resinous tubular portions are integrally formed at both ends of the resinous rod-like portions, and the respective tubular portions are formed in the respective tubular portions. In the case where an elastic body, preferably an elastic body having a rigid inner cylinder, is provided, a thick wall portion having a thick wall thickness over the entire length in the axial direction in a circumferential partial area of at least one tubular portion. Is provided, and the weld drain generated by the merging of the resin material is located in the thick portion.

Further, according to the manufacturing method of the present invention, at the time of manufacturing the connecting rod as described above by injection molding of a resin material, at least one cylindrical portion is made thick in a circumferential partial region, The resin materials that join each other are caused to flow into the resin reservoir located adjacent to the thick portion.

[0008]

In the connecting rod of the present invention, the weld line is positioned in the thick portion provided in the tubular portion so that the reduction in mechanical strength due to the occurrence of the weld line can be prevented by reducing the thickness of the thick wall portion. By making up for itself by increasing its strength,
It is possible to sufficiently enhance the strength of the weld line generation portion and effectively prevent damage to the connecting rod at that portion.

Further, in the method of the present invention, when the resin materials are merged, the mutual resin materials are caused to flow into the resin reservoir together so that the position of the weld line in the thick portion is adjacent to the resin reservoir. It is possible to accurately specify the position to be applied, and at the same time, the air in the cavity sandwiched between the merging resin materials, the generated gas of the resin material, etc. are allowed to escape to the resin reservoir, so It is possible to prevent entanglement and the like, and sufficiently prevent the strength of the thick portion from decreasing.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of the present invention, in which 1 denotes a linearly extending rod-shaped portion, and 2 denotes respective tubular portions integrally formed at both ends thereof. All of the parts are made of synthetic resin material.

The rod-shaped portion 1 has ribs 1a and 1b at both ends and a central portion in the width direction, and a thin portion 1c is provided between the ribs. Also,
Each of the tubular portions 2 has a cylindrical shape as a whole and has an axial length equal to that of the ribs 1 a and 1 b of the rod-shaped portion 1. A cylindrical elastic body 3 made of rubber or a rubber-like elastic material is provided in each of these cylindrical portions at the time of molding the cylindrical portion 2 or after the molding, and preferably,
At the innermost side of the elastic body 3, a rigid inner cylinder 3a for connecting to the connected member is provided.

By the way, in this example, one cylindrical portion 2
The outermost part of the, in other words, the one cylindrical part 2
Of the cylindrical portion 2 at the portion farthest from the rod-shaped portion 1.
The thick wall portion 4 has a thick wall portion 4 over its entire length in the axial direction. The thick wall portion 4 is made thickest on the central axis of the rod-shaped portion 1 and the tubular portion 2 is By gradually thinning it in the circumferential direction, preferably over an angular range of 30 ° or more, its thickened portion 4
The plane contour shape of is almost mountain-shaped. Then, again preferably, the maximum thickness t of the thick portion is set to be 1.5 times or more the thickness t ₀ of the other portion. In addition, such thick portion 4
Need not necessarily be positioned on the central axis of the rod-shaped portion 1, but the position can be appropriately changed in the circumferential direction of the tubular portion 2 as required.

Further, in the illustrated example, the weld line 5 generated by the merging of the resin material is located in the thick portion as described above, and preferably the weld line 5 is substantially as shown in the drawing. By extending the rod-shaped portion 1 on the axis of the rod-shaped portion 1, the weld line 5 has the thickest portion 4 of the thickest portion 4.
Against the decrease in strength due to the occurrence of.

FIG. 2 is an explanatory view of the method for manufacturing the connecting rod as described above. Here, in the state where each elastic body 3 is positioned and arranged in advance in the cavity, the thick portion 4
The resin material is injected from the gate A provided in communication with the molding space for forming the cylindrical portion 2 on the side opposite to the cylindrical portion 2 forming And through the molding space of the rod-shaped portion 1 sequentially into the molding space of the cylindrical portion 2 forming the thick-walled portion 4, and there, mutual interaction of the resin materials bypassing the elastic body 3 from each direction. The thick part 4
Through the molding space of (1) and into the resin pool of the cavity located adjacent to the molding space. After the resin reservoir is completely filled with the resin material in this way, each molding space in the cavity is gradually filled toward the gate side, and all the molding spaces are completely filled, so that the resin material is injected. Is stopped.

Therefore, here, the respective resin materials bypassing the elastic body 3 flow into the resin reservoir together, so that the weld line is formed in the thick portion 4 adjacent to the resin reservoir, that is, the thickest portion in the figure. 5 is reliably generated, the gas sandwiched between the respective resin materials is expelled to the resin pool, and the gas is entrained in the thick portion 4 and, by extension, the strength caused thereby. The decrease is sufficiently prevented.

According to the above description, the protrusion 6 formed by the resin pool is generated on the connecting rod, but the protrusion 6 is cut off after the completion of the forming, so that the function of the connecting rod is obtained. It will not cause any problems.

FIG. 3 is a view showing another connecting rod of the present invention. In this example, a thick wall portion 4 is formed on the outermost portion of each of the two tubular portions 2, and the inner end portions in the radial direction of the respective tubular portions 2 are provided on both end sides in the length direction thereof. The flange 2a is formed so as to squeeze out and enter the elastic body, and other configurations are substantially the same as those described above.

Such a connecting rod can be manufactured by opening a gate in the molding space of the rod-shaped part, and according to this, since each tubular part 2 has a thick part 4, both rods are formed. Further increase in strength can be ensured. In addition, according to this example, since the flange 2a formed on the tubular portion 2 can prevent intrusion of earth and sand or other foreign matter between the tubular portion 2 and the elastic body 3, the elastic body 3 and tubular part 2
However, it is possible to effectively prevent them from being damaged and improve durability. In the production of the connecting rod of this example, it is preferable to generate a protrusion formed by a resin reservoir in each thick portion 4.

FIG. 4 is a plan view showing still another connecting rod. This is because the rod-shaped portion 1 is bent in a substantially U-shape, and the tubular portions 2 are provided at both end portions thereof, and the bent end portion 1 of the rod-shaped portion 1 is provided in each tubular portion 2.
A thick portion 4 located on the axis of d is provided, and a weld line 5 is located at a portion of the thick portion 4 corresponding to the axis. In this connecting rod, the gate A is provided at a position corresponding to the central portion of the rod-shaped portion 1, and at the position corresponding to the axis of the bent end portion 1d,
By generating the protrusions 6 due to the resin pool, the position of the weld line 5 can be accurately specified at the above-described position, and the same effect as the above-described embodiment can be obtained.

[0020]

As described above, according to the connecting rod of the present invention, it is possible to effectively prevent a decrease in strength due to the occurrence of a weld line due to the presence of the thick portion provided in the tubular portion. According to the manufacturing method of the present invention, it is possible to generate a weld line at a desired position, and it is possible to sufficiently avoid a decrease in strength due to the entrainment of gas in the thick portion.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a connecting rod of the present invention.

FIG. 2 is an explanatory view of a method of manufacturing the connecting rod shown in FIG.

FIG. 3 is a diagram illustrating another connecting rod of the present invention.

FIG. 4 is a diagram illustrating still another connecting rod of the present invention.

[Explanation of symbols]

 1 Rod-shaped part 1d Bent end part 2 Cylindrical part 2a Flange 3 Elastic body 3a Rigid inner cylinder 4 Thick part 5 Weld line 6 Projection A Gate

Claims (2)

[Claims] 1. A rod-shaped part made of resin, a tubular part made of resin, which is integrally formed at both ends of the rod-shaped part, and elastic bodies arranged in the respective tubular parts. A resin-made connecting rod, wherein a thick-walled portion is provided in a circumferential partial area of at least one tubular portion, and a weld line is located in the thick-walled portion. 2. A resin material is injected into a cavity in which an elastic body is previously arranged, and a rod-shaped portion and cylindrical portions located at both ends of the rod-shaped portion and surrounding the elastic body are provided. In manufacturing a resin rod to be equipped with, at least one cylindrical portion is made thick in a circumferential partial area, and the resin material is caused to flow into a resin pool located adjacent to the thick portion. And a method of manufacturing a resin rod.