JPH08132834A - Connecting rod - Google Patents

Abstract

PURPOSE: To reduce weight and cost by forming a connecting rod with a tubular material. CONSTITUTION: A curved part 1a is formed by bending a part of a rod main body 1 made of a tubular material, the bar main body 1 is formed in a slender hollow cross section shape in the radius of curvature direction in the curved part 1a, a cylindrical body 2 almost perpendicularly crossing to the rod main body 1 is held by a cut-off part 1b formed in the curved part 1a, and in this state, welded to the rod main body 1, then reinforced with a rib 3. A tapered part 1c is formed at the other end of the rod main body 1, and male thread 4 is formed on the solid rod-shaped end 1d which is formed at the tip of the rod main body 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting rod used for a suspension system of an automobile.

[0002]

2. Description of the Related Art FIG. 7 is a side view schematically showing a link structure of a 3-link coil spring type suspension as an example of a suspension system for an automobile. As shown in the same figure, a lower arm bracket 13 attached to a rear axle housing 12 extending from both sides of a differential gear box 11 in a vehicle width direction (a direction perpendicular to the plane of the drawing) has a trailing portion for restricting movement of a wheel with respect to a vehicle body in a longitudinal direction. The arm 14 is connected so as to avoid interference with the rear axle housing 12. Further, a lateral rod 15 that restricts the movement of the wheels in the vehicle width direction is attached to the lower arm bracket 13, and a stabilizer 16 is connected to the rear axle housing 12 in order to obtain stability of vertical movement and lateral difference of the wheels. The trailing arm 14 is supported via a pivot portion using a rubber bush 17, as shown in an enlarged view of a main portion in FIGS. 8 and 9. In the figure, reference numeral 18 is an outer cylinder of the rubber bush 17 or a bush tube for attaching the rubber bush. The above-mentioned trailing arm 14 is usually forged with an H-shaped cross section having high rigidity, and a pivot portion is also provided at the other end of the trailing arm 14 which is omitted in FIG. A single part drawing of the trailing arm 14 is shown in FIGS.

[0003]

Therefore, when the above-mentioned conventional trailing arm is used, the unsprung weight of the suspension device becomes heavy and the suspension characteristics are restricted, and it is relatively expensive and difficult to reduce the cost. was there.

Therefore, an object of the present invention is to form a connecting rod such as a trailing arm with a tubular material to reduce the weight and the cost.

[0005]

[Means for Solving the Problems] For this purpose, the following connecting rod was created. That is, the invention according to claim 1 is a connecting rod used for a suspension system of an automobile, wherein one end of a rod main body made of a tubular material is bent to form a curved portion, and the rod main body is curved at the curved portion. A tubular body that is elongated in the radial direction and that is approximately orthogonal to the rod body is fixed to the rod body while being held by the notch provided in the curved portion, while the other end side of the rod body is formed into a taper shape. It is characterized by having done. According to a second aspect of the present invention, there is provided a connecting rod used in a suspension system for an automobile, wherein one end of a rod body made of a tubular material is bent to form a curved portion, and the rod body has a radius of curvature at the curved portion. While having a hollow cross-sectional shape elongated in the direction and being fixed to the rod body while inserting a tubular body that is substantially orthogonal to the rod body into the through hole provided in the curved portion, the other end of the rod body is formed into a taper shape. It is characterized by that. Further, in the invention according to claim 3, in the connecting rod according to claim 1, there is provided a reinforcing member that extends along a curved portion of the rod body and has a substantially U-shaped cross section that sandwiches the rod body. It is characterized in that the U-shaped tip of the reinforcing member is welded at a position substantially intersecting the neutral surface of the curved portion. The invention according to claim 4 is the connecting rod according to claim 3, characterized in that a buffer member is interposed between the curved portion of the rod body and the U-shaped inner bottom of the reinforcing member.

[0006]

[Operation] In the above-mentioned connecting rod, the main body of the rod at the curved portion is
The required bending rigidity can be easily ensured by making the hollow cross-sectional shape elongated in the radius of curvature direction. Further, by fixing the tubular body to the curved portion to facilitate attachment of, for example, a rubber bush, while making the other end tapered to facilitate formation of a male screw for attachment at the tip,
The connecting rod has a simple structure including a mounting portion that is usually a pivot portion, and compared with the forged structure and the pressed steel plate product, it is possible to significantly reduce the cost in combination with the reduction in weight. Also, by welding the reinforcing member that covers the curved portion of the rod body at a position where the skin stress that appears during use is relatively small and where it almost intersects the neutral surface of the curved portion, the base metal structure of the rod body becomes rough due to welding. Even if the fatigue strength may be partially reduced, the influence on the strength can be less likely to occur as compared with the case where the fatigue strength is welded to another position (for example, the inner and outer circumferences of the curved portion). In addition, a cushioning effect is provided by interposing a cushioning member between the curved portion of the rod body and the U-shaped inner bottom of the reinforcing member.

[0007]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a front view showing a connecting rod according to the first embodiment, and FIG. 2 is a sectional view taken along line AA, BB, CC of FIG. As shown in both figures, the rod main body 1 is formed by forming a tubular material such as a steel pipe into a roughly illustrated shape, and a curved portion 1a is formed at the right end by bending, and the curved portion 1a is formed. The cross-sectional shape is formed in a hollow oval shape elongated in the radius of curvature of the curve. And the inner circumference side 2 of the curve
The portion is cut out in a substantially semicircular shape, and the cylindrical bodies 2 and 2 orthogonal to the rod main body 1 are fitted and welded to the cutout portions 1b and 1b. Further, a plate-shaped rib 3 is welded to the rod main body 1 in a state of abutting against the one tubular body 2 and covering the other tubular body 2, and the joint portion between the curved portion 1a and the tubular body 2 is reinforced. ing. Further, the left end side of the rod main body 1 is gradually reduced in diameter from the curved portion 1a by swaging, and the tip of the taper portion 1c is further compression-molded to form a solid rod-shaped end portion 1d. Are formed. In addition, in FIG.
The imaginary line shows the outline before swaging.

One purpose of the connecting rod formed as described above is to replace the forged trailing arm 14 (see FIGS. 7 to 9) described above as a conventional example, for example. That is, the cylindrical body 2 serves as a so-called bush tube, and a rubber bush having the same structure as that of the conventional example is attached thereto, while a rubber bush, a ball joint or the like is attached to the male screw 4 of the rod-shaped end portion 1d (not shown). ), The mounting portions at both ends thereof are pivot portions that constitute the link mechanism of the suspension device.

Therefore, in the connecting rod of the first embodiment, since the rod main body 1 has a hollow cross-sectional shape elongated in the radius of curvature direction, it is easy to secure the required bending rigidity in the curved portion. Further, while the tubular body 2 is fixed to the curved portion, the male screw 4 is formed at the tip of the tapered portion 1c. Therefore, the connecting rod has a simple structure including the mounting part that is usually the rubber bush and is the pivot part of the link mechanism, and it is significantly lighter than the conventional forged structure and pressed steel plate products. Cost reduction is possible. Since the natural frequency of the suspension system is increased by reducing the weight of the connecting rod, the suspension characteristics such as responsiveness are improved.

Next, the connecting rod according to the second embodiment will be described. The rod main body 5 shown in FIG. 3 has substantially the same configuration as the rod main body 1 described above, but the cross-sectional shape of the curved portion 5a is hollow and substantially triangular as shown in FIG. The cylindrical body 2 is inserted into the through hole 5b and welded. The rod-shaped end portion 5d and the male screw 6 are the same as those of the rod body 1 of the first embodiment. Therefore,
In this example, as compared with the connecting rod of the first embodiment, since there is no rib to be welded, the processing steps are simple and the manufacturing is easy.

Next, the connecting rod according to the third embodiment will be described. The rod main body 7 shown in FIG. 5 is configured such that a reinforcing member 8 having a substantially U-shaped cross section is attached in place of the rib 3 in the rod main body 1 of the first embodiment described above. Both ends of the tubular body 2 are inserted through the mounting holes 8a. The cylindrical body 2 is welded to the semicircular notch peripheral edge of the curved portion 7a and the peripheral edge of the mounting hole of the reinforcing member 8. Moreover, the U-shaped tip of the reinforcing member 8 has the curved portion 7a.
It extends to a position where it intersects with the neutral plane N, and is welded there. A buffer member 9 such as urethane or rubber is interposed between the curved portion 7a of the rod body 7 and the U-shaped inner bottom of the reinforcing member 8.

Therefore, in this example, since the reinforcing member 8 is a reinforcing shell, the cylindrical body 2 is more firmly fixed and the rigidity of the mounting portion is increased as compared with the connecting rod of the first embodiment. Further, since the reinforcing member 8 is welded to the rod body 7 at a position where the skin stress that appears during use is relatively small and which substantially intersects the neutral surface N of the curved portion 7a, the base material of the rod body 7 is welded. Even if the tissue is roughened and the fatigue strength is partially reduced, the strength is less likely to be affected as compared with the case of welding at other positions (for example, the inner and outer circumferences of the curved portion). Therefore, the reliability of the connecting rod is improved. Also,
The cushioning member 9 interposed between the curved portion 7a of the rod main body 7 and the U-shaped inner bottom of the reinforcing member 8 has a cushioning effect of weakening the shock transmitted to the connecting rod.

The connecting rod (trailing arm) made of the tubular material described in the embodiment can be reduced in weight by about 65% as compared with the conventional cast steel.

[0014]

As described above, in the connecting rod of the present invention, since the rod main body has the hollow cross-sectional shape elongated in the radius of curvature direction, it is easy to secure the required bending rigidity in the curved portion. Further, since the tubular body is fixed to the curved portion to facilitate attachment of, for example, a rubber bush, while the other end is tapered to facilitate formation of, for example, a male screw for attachment at the tip, the connecting rod is usually a pivot. It has a simple structure including the mounting part, which is a part of the forged structure and the steel plate pressed product, which enables a significant cost reduction in combination with the reduction in weight. In addition, since the reinforcing member having a substantially U-shaped cross section is welded at a position where the skin stress that appears during use is relatively small and substantially intersects the neutral surface of the curved portion, the base material structure of the rod main body is roughened by the welding. Even if the fatigue strength may be partially reduced, it is less likely to be affected in terms of strength as compared with the case where the fatigue strength is welded to another position (for example, the inner and outer circumferences of the curved portion). In addition, a cushioning effect is provided by interposing a cushioning member between the curved portion of the rod body and the U-shaped inner bottom of the reinforcing member. By using the connecting rod of the present invention, it is possible to reduce the weight and cost of the suspension device.

[Brief description of drawings]

FIG. 1 is a front view showing a connecting rod according to a first embodiment.

FIG. 2 is a cross-sectional view of the connecting rod according to the first embodiment,
1A is a cross section taken along the line AA of FIG. 1, FIG. 1B is a cross section taken along the line BB, and FIG.

FIG. 3 is a front view showing a connecting rod according to a second embodiment.

FIG. 4 is a cross-sectional view of a connecting rod according to a second embodiment,
1D is a cross section taken along the line DD of FIG. 1, FIG. 6E is a cross section taken along the line EE, and FIG.

FIG. 5 is a front view showing a main part of a connecting rod according to a third embodiment.

6 is a sectional view taken along line GG of FIG.

FIG. 7 is a side view schematically showing a link structure of a three-link coil spring suspension of an automobile.

FIG. 8 is an enlarged view of a main part showing a connection state between the lower arm bracket and the trailing arm of FIG. 7.

9 is a sectional view taken along line HH of FIG.

FIG. 10 is a front view of a trailing arm according to a conventional example.

11 is a cross-sectional view of a trailing arm according to a conventional example, (J) is a cross section taken along line JJ of FIG. 10, (K) is the same K-.
The K-line cross section is shown.

[Explanation of symbols]

 1, 5, 7 Rod main body 1a, 5a, 7a Curved portion 1b, 7b Cutout portion 1c, 5c, 7c Tapered portion 1d, 5d Rod end 2 Tubular body 3 Rib 4 Male screw 5b Through hole 8 Reinforcing member 9 Buffer member

Claims (4)

[Claims] 1. A connecting rod used for a suspension system of an automobile, wherein one end of a rod main body made of a tubular material is bent to form a curved portion, and the rod main body is elongated in the radius of curvature in the curved portion. A connecting rod having a cross-sectional shape and a tubular body that is substantially orthogonal to the rod main body is fixed to the rod main body while being held by the notch formed in the curved portion, while the other end side of the rod main body is formed into a taper shape. . 2. A connecting rod used for a suspension system of a vehicle, wherein one end of a rod main body made of a tubular material is bent to form a curved portion, and the rod main body is elongated hollow in the radius of curvature at the curved portion. A connecting rod having a cross-sectional shape and being fixed to the rod main body while inserting a tubular body that is substantially orthogonal to the rod main body into the through hole provided in the curved portion, while the other end side of the rod main body is formed in a taper shape. . 3. The connecting rod according to claim 1, further comprising a reinforcing member extending in a curved portion of the rod main body and having a substantially U-shaped cross section sandwiching the rod main body, and the U-shaped reinforcing member. A connecting rod characterized in that the tip of is welded at a position substantially intersecting the neutral surface of the curved portion. 4. The connecting rod according to claim 3, wherein a buffer member is interposed between the curved portion of the rod main body and the U-shaped inner bottom of the reinforcing member.