JP2001269740A - Metal rod and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal rod having a connection structure of a first metal rod and a second metal rod which can stably give high strength to the connection portion. SOLUTION: A thin-walled metal sleeve 32 is externally inserted into an end in the axial direction of the second metal rod 20, and the end in the axial direction of the second metal rod 20 is externally inserted into an end in the axial direction of the first metal rod 18 having grooves 30, 30, 30 in the circumferential direction. By caulking the metal sleeve 32, the second metal rod 20 and the metal sleeve 32 are plastically deformed in a closely tightened state to each other, and fitted and fixed to circumferential grooves 30, 30, 30 of the first metal rod 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal rod, such as a suspension arm for an automobile or an engine torque rod, which spans between predetermined members and connects both members.

[0002]

2. Description of the Related Art Conventionally, at least one end portion of a longitudinal rod-shaped shaft portion has been used as one type of a connecting member that is stretched between predetermined members to regulate the relative displacement of the two members and transmit a driving force. It is known that a joint portion such as an arm eye is provided on the vehicle, and a joint device such as a rubber bush, a ball joint, and a pillow ball bush is mounted on the joint portion. Are used as various types of rods and arms, or as connecting rods for power units, differential carriers and bodies.

In order to achieve the required strength, such a connecting rod is generally formed of a metal material such as an iron-based material or an aluminum alloy. , A connecting rod is integrally formed with a hollow joint such as an arm eye by cutting an appropriate length, (b) a method of forging the connecting rod integrally with the joint, (c) a connecting rod. And (d) forming the connecting rod and the joint separately, and then fixing them by MIG welding, FSW welding, or FW welding.

[0004] However, the connecting rod obtained by the extrusion molding in the above (a) has a small degree of freedom in shape design because the forming direction of the hollow joint is limited to the extrusion direction. In addition, there is a problem that the strength of the member becomes directional due to the influence of the extrusion direction. In addition, the connecting rod obtained by forging in (b) is inevitably expensive due to the manufacturing cost, and the connecting rod obtained by casting in (c) has quality stability such as member strength. There was a problem that it was difficult to obtain. Furthermore, the connecting rod obtained by the welding in (d) has a joint efficiency (ratio of the strength of the joint to the strength of the base material) of 0. Since it is reduced to about 5 to 0.7, there is a problem that it is difficult to obtain the strength of the entire connecting rod.

[0005]

Here, the present invention has been made in view of the above-mentioned circumstances, and the object of the present invention is to reduce or avoid the directionality of the member strength.
An object of the present invention is to provide a metal rod having a novel structure capable of stably obtaining high-strength characteristics and a method for manufacturing the same.

[0006]

An embodiment of the present invention which has been made to solve such a problem will be described below. The components employed in each of the embodiments described below can be employed in any combination as possible. In addition, aspects or technical features of the present invention are not limited to those described below, but are described in the entire specification and drawings, or based on the invention ideas that can be understood by those skilled in the art from the descriptions. It should be understood that it is recognized on the basis of.

That is, a feature of the present invention relating to a metal rod is a metal rod in which the axial end of the second metal rod is connected and fixed to the axial end of the first metal rod. In the outer peripheral surface at the axial end of the first metal rod, at least two circumferential grooves extending continuously or discontinuously in the circumferential direction are formed in the axial direction, while at least two circumferential grooves are formed. Along the axial end of the first metal rod, the axial end of the metal rod is cylindrically arranged and extrapolated to the axial end of the second metal rod. The metal sleeve formed separately from the metal rod is extrapolated and arranged, and the metal sleeve and the second metal rod are deformed in close contact with each other, and the second metal rod is brought into contact with the first metal rod. Insert into the circumferential groove of the rod and fix it Lies in the fact was.

In the metal rod having the structure according to the present invention, the metal sleeve is extrapolated to the second metal rod fitted in the circumferential groove of the first metal rod so that the second metal rod is in close contact with the second metal rod. In this arrangement, the metal sleeve acts as a reinforcing member for the connecting portion of the second metal rod, and can exert a deformation resistance in the expanding direction on the fitting portion of the second metal rod. Becomes Therefore, when an external force in the axial direction is applied to the connection portion between the first metal rod and the second metal rod, a large locking is formed between the two metal rods at the portion where the circumferential groove of the first metal rod is formed. Since the fixing force is exerted, a high-strength metal rod can be realized as a whole. Moreover, when connecting the first metal rod and the second metal rod, there is no need to heat the two metal rods, so that there is no problem such as a decrease in strength due to heat treatment.

In such a metal rod,
When the cylindrical portion of the second metal rod is reduced in diameter by caulking or the like and fitted into the circumferential groove of the first metal rod, for example, a processing external force such as a caulking force is applied to the second metal rod via a metal sleeve. Since it can exert on the metal rod, it is possible to apply a large external force to the second metal rod while reducing or avoiding scratches and local thinning of the second metal rod. Thereby, the direct locking force itself based on the fitting of the second metal rod to the circumferential groove of the first metal rod can be advantageously obtained. That is, since the metal sleeve and the second metal rod have a double-pipe structure, a processing external force applied to the metal sleeve causes deformation of the metal sleeve itself and a boundary surface between the metal sleeve and the second metal rod. Is dispersed and exerted on the second metal rod by the slipping action, thereby making the external working force exerted on the second metal rod uniform and stable.

Further, in the metal rod having the structure according to the present invention, the first metal rod and the second metal rod formed separately from each other are connected by mechanically fitting in a post-process. Therefore, there is no restriction on the material and manufacturing method of the first and second metal rods. Therefore, the required strength of the member can be easily realized, and there is no problem in which a specific direction regarding the strength of the member becomes a problem. Specifically, in both the first and second metal rods, various materials such as steel and aluminum alloy can be adopted as the material, and particularly, aluminum alloy and the like which are easy to plastically process and have little springback can be used. Is preferably adopted. Also,
As a manufacturing method, for example, various processing methods such as extrusion molding, casting, and forging can be adopted. Furthermore, the first metal rod and the second metal rod can be made of different materials or manufactured by different methods in consideration of required characteristics.

In addition, various materials and manufacturing methods can be adopted for the metal sleeve irrespective of the first and second metal rods. Preferably, the second metal rod and the metal sleeve are made of the same material. . By adopting the second metal rod and the metal sleeve of the same material, it is easy to caulk both members at the same time and to fit in the circumferential groove of the first metal rod in close contact. Thereby, for example, due to a reduction in the reinforcing effect of the metal sleeve on the second metal rod due to the springback of the metal sleeve, or due to local stress transmission to the second metal rod through the metal sleeve. Occurrence of stress concentration sites in the second metal rod and the like can be reduced or avoided. Furthermore, when using a metal sleeve of the same material as the second metal rod, it is desirable to make the metal sleeve thinner than the cylindrical axial end of the second metal rod, When caulking the second metal rod via the metal sleeve, the second metal rod can be more easily fitted into the circumferential groove of the first metal rod.

Furthermore, it is desirable that the axial end of the first metal rod has a deformation rigidity greater than at least the second metal rod at the portion where the circumferential groove is formed, and more preferably such first rigid rod. The axial end of the metal rod has a solid structure. Thereby, the deformation of the first metal rod when the second metal rod is fitted into the circumferential groove of the first metal rod is advantageously prevented, and the first metal rod and the second metal rod are prevented from being deformed. The connection strength can be more stably obtained.

In the present invention, a deformed portion having an outer diameter different in a circumferential direction is provided on at least a part of an externally fixed portion of the second metal rod in the first metal rod,
The second metal rod may be extrapolated in close contact with the deformed portion. Thereby, the connection fixing force in the circumferential direction between the first metal rod and the second metal rod can be advantageously obtained. In addition, specifically, such a deformed portion is, for example, an outer peripheral surface or a circumferential groove of the first metal rod to which the second metal rod is inserted and fixed by being externally inserted. This can be realized by forming a non-circular shape, or by forming a convex portion or a concave portion on the outer peripheral surface or the circumferential groove of the first metal rod.

It is desirable that the first metal rod and the second metal rod are brought into close contact with each other over the entire surface of the first metal rod at the portion where the first metal rod is fitted and fixed in the circumferential groove of the first metal rod. . By fitting the second metal rod in close contact with the entire bottom surface and both side surfaces of the circumferential groove of the first metal rod, the connection between the first metal rod and the second metal rod The occurrence of backlash is prevented, and a large connection strength can be obtained with excellent durability.

Preferably, the metal sleeve is disposed over the entire length of the portion of the second metal rod that is extrapolated to the first metal rod, and more preferably, the metal sleeve is entirely formed. The second metal rod is tightly attached to the outer peripheral surface of the first metal rod over the entire length of the extrapolated portion to the first metal rod, while being extrapolated and fixed to the second metal rod in close contact with the second metal rod. State. Thereby, not only the fitting portion of the second metal rod into the circumferential groove of the first metal rod, but also a larger connecting force as a whole is exerted.

Further, the metal rod to which the present invention is applied is not particularly limited with respect to its use and the like. Specifically, for example, the present invention can be advantageously applied to a rod member for an automobile in which a tensile / compressive load is applied in the axial direction of the first and second metal rods. More specifically, such as a suspension arm for an automobile or a torque rod of a power unit.

The metal rod to which the present invention is applied is as follows:
The thickness, length, cross-sectional shape, overall shape, and the like are appropriately changed depending on the use and the like, and are not particularly limited. Specifically, for example, the present invention is advantageously applied to a connecting rod in which a joint portion is formed with respect to an axial end opposite to a connecting side of the first metal rod with the second metal rod. Can be applied. More specifically, such joints include a cylindrical arm eye to which a vibration isolating bush or the like is mounted, and a ball joint.

On the other hand, the feature of the present invention relating to the method of manufacturing a metal rod is that the axial end of the second metal rod is connected and fixed to the axial end of the first metal rod. When obtaining an integral metal rod, at least two circumferential grooves extending continuously or discontinuously in the circumferential direction are formed on the outer peripheral surface of the axial end portion of the first metal rod in the axial direction. On the other hand, the axial end of the second metal rod is cylindrical and extrapolated to the axial end of the first metal rod, and the axial end of the second metal rod is formed with respect to the axial end of the second metal rod. By extrapolating a metal sleeve formed separately from the first and second metal rods and caulking the metal sleeve, the metal sleeve and the second metal rod are plastically deformed in close contact with each other. Let me
The present invention is a method for manufacturing a metal rod, wherein the second metal rod is inserted into a circumferential groove of the first metal rod and fitted and fixed.

According to the method of the present invention, it is possible to advantageously manufacture a metal rod having the end connecting structure according to the present invention as described above, and the first metal rods formed separately from each other. , The second metal rod and the metal sleeve are inserted into and out of each other, and a caulking force is applied from the outer peripheral surface of the metal sleeve to integrally reduce the diameter of the metal sleeve and the second metal rod to form the first metal rod. By fitting and fixing in the circumferential groove, the second metal sleeve can be inserted into the circumferential groove of the first metal sleeve in a state where the metal sleeve and the second metal rod are in close contact with each other.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

First, FIGS. 1 and 2 show a vehicle suspension arm 10 according to an embodiment of the present invention. The suspension arm 10 includes a main body rod 12 having a straight longitudinal rod shape, and a pair of arm eyes 14 as fixed joints formed at both axial ends of the main body rod 12. I have. Rubber bushes 16, 16 are mounted on the arm eyes 14, 14, respectively. The suspension arm 10 has both ends in the axial direction attached to the body-side member and the wheel-side member (not shown) via the rubber bushes 16, 16 to connect the wheel-side member to the body-side member in a vibration-proof manner. It has become.

More specifically, the suspension arm 10
Is composed of a pair of arm eyes 14,
14 and a pair of end rods 18, 18 as first metal rods respectively formed integrally with each other,
8, 18 are constituted by a central rod 20 as a second metal rod fixed to both ends.

Here, the arm eye 14 has a cylindrical shape, and is formed integrally with a U-shaped frame-shaped mounting portion 22 protruding outward in the radial direction with respect to the outer peripheral surface thereof. The end rod 18 is integrally formed at the center of the protruding tip surface of the portion 22. The end rod 18 has a straight solid circular rod shape, and has a central axis orthogonal to the central axis of the arm eye 14.

In the present embodiment, the end rod 18, the mounting portion 22, and the arm eye 14 are formed of an integral die-cast product of an aluminum alloy. A rubber bush 16 is mounted inside the hollow of the arm eye 14. Such a rubber bush 16
Has a small-diameter cylindrical shaft fitting 24 and a thick cylindrical rubber elastic body 26. The shaft fitting 24 is inserted through the arm eye 14, and is coaxially arranged radially inward of the arm eye 14. With the shaft fitting 24 and the arm eye 14
A rubber elastic body 26 having a thick cylindrical shape is interposed between the radially opposite surfaces, and the shaft fitting 24 is elastically connected to the arm eye 14 by the rubber elastic body 26. The shaft fitting 24 of each rubber bush 16 is attached to a wheel-side member or a body-side member (not shown). The rubber elastic body 26 has a pair of arcuate plate-like reinforcing members 28, 28 fixed in a portion facing each other in one radial direction across the shaft member 24 in a penetrating state. The right angle spring ratio is adjusted. The rubber bush 16 can be assembled by press-fitting a vulcanized molded product of a rubber elastic body 26 having a shaft fitting 24 into the arm eye 14. By setting and vulcanizing the rubber elastic body 26, the rubber elastic body 26 may be formed as an integral vulcanized molded product including the shaft fitting 24 and the arm eye 14.

The end rod 18 integrally formed with the arm eye 14 has annular grooves 30 and 3 on its outer peripheral surface as three circumferential grooves extending in the circumferential direction, respectively.
0, 30 are formed spaced apart from each other in the axial direction.
Each of these annular grooves 30, 30, 30 is formed continuously in the circumferential direction with a constant inverted trapezoidal cross section that expands toward the outer peripheral side. In addition, the annular grooves 30, 30, 30
May be formed simultaneously with the formation of the end rod 18 or may be formed by post-processing such as cutting after the formation of the end rod 18.

On the other hand, the center rod 20 has a cylindrical shape whose inner and outer diameters are substantially constant over the entire length in the axial direction. In the present embodiment, the central rod 20 is
It is formed by cutting a pipe material, which is an extruded product of an aluminum alloy, into an appropriate length. And
The end rods 18 are inserted into both ends of the central rod 20 in the axial direction.
0 is configured.

A metal tube 32 as a metal sleeve is externally attached to each of both ends in the axial direction of the center rod 20 externally inserted into each end rod 18. The metal tube 32 has a length in the axial direction that covers the external insertion portion of the center rod 20 with respect to the end rod 18 over the entire length, and has an inner diameter corresponding to the outer diameter of the center rod 20. The center rod 20 is fitted and fixed in close contact with the outer peripheral surface of the central rod 20. In the present embodiment, the metal tube 32 is formed by cutting a pipe material, which is an extruded product of an aluminum alloy of the same material as that of the central rod 20, at an appropriate length.
In the present embodiment, a metal tube having a smaller thickness than the center rod 20 is used as the metal tube 32.

Next, the suspension arm 1 as described above is used.
An embodiment of the manufacturing method according to the present invention will be described.

First, as shown in FIG. 3, a center rod 20 obtained by cutting a pipe material, which is an extruded product of an aluminum alloy, into an appropriate length, as described above, The tube 32 is prepared, and the metal tube 32 is extrapolated to the axial end of the central rod 20 and assembled. In order to facilitate the operation of inserting the metal tube 32 into the center rod 20, the metal tube 32 having an inner diameter slightly larger than the outer diameter of the center rod 20 may be employed. desirable.

As shown in FIG. 4, the end rod 18 integrally formed with the arm eye 14 and the mounting portion 22 is formed separately by die casting or the like as described above, and the arm eye 14 is formed. The rubber bush 16 is attached to the. And such end rod 18
The central rod 2 with the metal tube 32 extrapolated as described above
0 and inserted into the open end.

Thereafter, as shown in FIG. 5, a central rod 20 extrapolated to the end rod 18 and a metal tube 32
By applying an external force in the diameter reducing direction using the caulking jig 34, the metal tube 32 and the central rod 20 are drawn and deformed in the diameter reducing direction. Thereby, the metal tube 32 and the central rod 20 are brought into close contact with each other, and
To the end rod 18. In this caulking process, for example, a known octagonal drawing process or the like can be applied.For example, as shown, using a caulking jig 34 composed of a plurality of divided jigs divided in the circumferential direction, These division jigs can be made by contacting the outer peripheral surface of the metal tube body 32 and applying a pressing force radially inward to each division jig.

The caulking jig 34 has annular concave grooves 30, 30, 30 formed on the outer peripheral surface of the end rod 18 with respect to the pressing surface brought into contact with the metal tube 32.
Annular projections 36, 3 extending continuously in the circumferential direction corresponding to
6, 36 are provided. And these annular projections 3
The pressing force is transmitted to the central rod 20 by the metal tube 32 being pressed by 6, 36, 36, so that the central rod 20 enters the annular concave grooves 30, 30, 30 and is superimposed substantially in close contact. It has become.

Therefore, in the suspension arm 10 of the present embodiment manufactured as described above, the annular ridges 38, 38, 38 corresponding to the annular grooves 30, 30, 30 of the end rod 18 are formed by the central rod 20. And the annular projections 38, 38, 38 are fitted in the annular grooves 30, 30, 30, so that the connecting portion between the end rod 18 and the central rod 20 can be axially or twisted. Large fixing strength can be exhibited. Moreover, in addition to the above, a metal tube 32 is externally fitted to the center rod 20, and
Since the rigidity of the center rod 20 is improved by the reinforcing action of the metal tube 32, the fixing strength between the end rod 18 and the center rod 20 can be further improved.

When caulking the center rod 20, the caulking force is applied via the metal tube 32 to the center rod 20.
Therefore, the caulking force exerted on the central rod 20 is dispersed, so that stress concentration and thinning due to local deformation of the central rod 20 are prevented, whereby the central rod 20 and the end rod Thus, the desired connection strength can be stably obtained between 18.

In addition, the center rod 20 is
As compared with No. 8, since it is plastically deformed by caulking and is fitted and fixed, there is no problem of reduction in connection strength or instability due to thermal influence.

In comparison with forging, caulking is
Since the machining cycle is good at a relatively low cost and excellent productivity can be achieved, and since the joint strength of the connecting part can be secured to the same level as or higher than that of the base material, the central rod is required. It is also possible to make the suspension arm thinner, whereby the weight and cost of the suspension arm can be reduced.

Incidentally, in order to confirm the connection strength of the connection portion in the suspension arm as described above, an experiment was performed using a test piece.

As shown in FIG. 6, the test piece subjected to the experiment has an annular concave groove 30 similar to the end rod 18 in the above-described embodiment, with respect to the distal end portion of a solid circular rod material. The first metal rod 42 is formed by forming the annular groove portion 40 of the second metal rod 42, and the second metal rod 44 is formed by forming the connection side end of the circular rod material into a hollow cylindrical shape,
As in the case of the main body rod 12 in the above embodiment, a metal sleeve 46 as the metal tube 32 is externally inserted into the second metal rod 44 and caulked to form the metal sleeve 46 and the second metal rod 44. The diameter was reduced in the close contact state, and the second metal rod 44 was fitted and fixed to the annular grooves 40, 40 of the first metal rod 42 in the close contact state. The first and second metal rods 42 and 44 and the metal sleeve 46 in the test piece are used.
Are aluminum alloy materials (material: A60
61-T6), which was formed by cutting an extruded material.
In the test piece, the outer diameter of the portion of the first metal rod 42 where the annular groove 40 is not formed is φ1.
7.5 mm, the inner diameter and the outer diameter of the portion of the second metal rod 44 not fitted in the annular groove 40 are φ1
7.5 mm and 22.5 mm, the inner and outer diameters of the portion of the metal sleeve 46 not fitted in the annular groove 40 were 22.5 mm and 24 mm, respectively, and the axial length of the metal sleeve 46 was 45 mm.

The outer end of the first metal rod 42 in the test piece and the second metal rod 44
Chuck the outer end of each, and pull in the axial direction /
By repeatedly applying a compressive load at 8mm and measuring the number of repeated actions of the load until the test piece breaks,
The joint strength was evaluated. The result is shown in FIG. As a comparative example, the second metal rod 44 alone (Comparative Example 1), the first metal rod 42 and the second metal rod 44
(Comparative example 2), a first metal rod 42 and a second metal rod 44 subjected to FSW welding (comparative example 3), a first metal rod 42 and a second metal rod 44 Was subjected to MIG welding (Comparative Example 4), and similar tests were performed. The test results are also shown in FIG. It should be noted that a shown on the vertical axis of the graph shown in FIG.
Is a constant.

From the test results shown in FIG. 7, in the connection structure according to the present invention, a connection strength comparable to the strength of the second metal rod 44 as the base material can be obtained stably. Is recognized.

Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention is not construed as being limited by the specific description in the embodiment.

For example, in the above embodiment, the central rod 2
When the diameter of the metal tube 32 is reduced to fit in the annular groove 30 of the end rod 18, diameter reduction using a plurality of caulking jigs 34 similar to swaging has been employed. However, the center rod 20 and the metal tube 32 may be reduced in diameter by roll caulking or spattling.

In the above embodiment, the end rod 18
The central rod 20 and the metal pipe 3
2 are fitted and fixed while being uniformly reduced in diameter over the entire circumference. However, for example, as shown in FIGS. In order to reduce caulking pressure in response to meat, etc.
It is also possible to press the metal tube 32 with a caulking jig at a plurality of locations spaced apart in the circumferential direction.

Further, as shown in FIGS. 10 to 11, the end rod 18 has a non-circular cross-sectional shape such as a hexagon except for the portion where the annular groove 30 is formed, and has a central rod on its surface. It is also possible to externally fix the outer tube 20, whereby the connection strength in the circumferential direction (torsion direction) at the connection portion between the center rod 20 and the end rod 18 can be improved.
In order to secure the connection strength in the circumferential direction, for example, as shown in FIGS. 12 and 13, the bottom wall surface of the annular groove 30 in the end rod 18 is formed into a non-circular cross-sectional shape such as a two-sided width. It is also effective to tightly fit and fix the center rod 20 to the bottom wall of the annular groove 30. Further, as shown in FIG. 14, the bottom wall surface of the annular groove 30 corresponding to FIG. 13 has a concave cross-sectional shape in which an arc-shaped recess that is less than half a circumference is provided at two places in the circumferential direction. As
In other words, the central rod 20 is closely fitted and fixed to the bottom wall surface of the annular groove 30 as a convex cross-sectional shape provided with two convex portions spaced apart in the circumferential direction. Thereby, the connection strength can be increased.

The large-diameter portion shown in FIG. 11 and the small-diameter portion shown in FIGS. 13 and 14 of the above-mentioned end rod 18 can of course be used in appropriate combination. In FIGS. 8 to 14, members and portions having the same structure as in the above-described embodiment are denoted by the same reference numerals as those in the above-described embodiment for easy understanding.

Further, in the above embodiment, the end rod 1
8, the central rod 20 is fitted in close contact with the entire surface of the annular groove 30 formed in the annular groove 8; It is also possible to make the central rod 20 close together or to make the center rod 20 close only at a part of the annular groove 30 in the longitudinal direction (circumferential direction), for example, only at both sides facing in the radial direction. The connection structure may be appropriately adopted according to the required connection strength and the like.

In the above embodiment, the central rod 20
Although the metal tube 32 is extrapolated and mounted only at the end of the central rod 20, the metal tube 32 may be extrapolated over the entire length of the central rod 20.

Further, in the above embodiment, a specific example in which three annular grooves 30, 30, 30 are formed in the end rod 18 has been described.
It is sufficient if there are two or more, for example, in the above embodiment,
Three annular grooves 30, 30, 3 in the end rod 18
It is also possible to adopt a structure in which any one of 0 is not provided.

The annular groove 3 in the end rod 18
In other words, 0 can be considered to mean that an annular convex portion is formed. That is, in the present invention, at least two circumferential protrusions extending continuously or discontinuously in the circumferential direction are formed in the end rod 18 at intervals in the axial direction, and the central rod 20 and the A structure in which the metal tube 32 is externally fitted and fixed can also be adopted, and even in such a structure, the effects of the present invention can be effectively exhibited.

Furthermore, in the above embodiment, the central rod 20 has a hollow tubular structure over the entire length, but only the end connected to the end rod 18 has the hollow tubular structure. The central portion may have a solid rod structure.

Further, the end rod 18 and the center rod 20
May be curved or bent.

The present invention is similarly applicable to the main body rod 12 having a structure in which one end rod 18 is connected and fixed to only one end in the axial direction of the center rod 20.

In addition, in the above-described embodiment, a specific example in which the present invention is applied to a suspension arm of an automobile is shown. However, the present invention is applied to a metal rod used for an automobile or various devices other than an automobile. Of course, both are applicable.

In addition, although not enumerated one by one, the present invention
Based on the knowledge of those skilled in the art, the present invention can be implemented in a form in which various changes, modifications, improvements, and the like are made.
It goes without saying that all such embodiments are included in the scope of the present invention without departing from the spirit of the present invention.

[0055]

As is apparent from the above description, in the metal rod having the structure according to the present invention, the first metal in the second metal rod is formed by the metal sleeve extrapolated to the second metal rod. Since the fitting portion of the rod into the annular groove is protected and reinforced, stress concentration due to local deformation and damage of the second metal rod at the time of assembling, and second stress after assembling, Any of the plastic deformation of the metal rods in the direction of expanding and detaching can be reduced or prevented, whereby the first metal rod and the second metal rod can be firmly connected and fixed.

Therefore, the first metal rod and the second metal rod, each manufactured by an arbitrary material and processing method, are firmly connected to each other to form a metal rod having the desired strength and characteristics. You can get it.

Further, according to the method of the present invention, the metal rod having the structure according to the present invention as described above can be manufactured at low cost and with an excellent processing cycle by using caulking.

[Brief description of the drawings]

FIG. 1 is a plan view of a vehicle suspension arm according to an embodiment of the present invention.

FIG. 2 is an enlarged longitudinal sectional view showing a main part of the suspension arm shown in FIG. 1;

FIG. 3 is a schematic view for explaining a manufacturing process of the suspension arm shown in FIG. 1;

FIG. 4 is a schematic diagram for explaining a manufacturing process of the suspension arm as a manufacturing process after FIG. 3;

FIG. 5 is a schematic diagram for explaining a manufacturing process of the suspension arm as a manufacturing process after FIG. 4;

6 is a longitudinal sectional view showing a test piece used for an experiment for verifying the strength of the connection structure in the suspension arm shown in FIG.

FIG. 7 is a graph (SN curve) showing the result data of a durability test using the test piece shown in FIG. 6;

FIG. 8 is a front view showing a main part of a vehicle suspension arm as another embodiment of the present invention.

9 is a sectional view taken along line IX-IX in FIG.

FIG. 10 is a front view showing a main part of a vehicle suspension arm as still another embodiment of the present invention.

11 is a sectional view taken along line XI-XI in FIG.

FIG. 12 is a front view showing a main part of a vehicle suspension arm as still another embodiment of the present invention.

FIG. 13 is a sectional view taken along line XIII-XIII in FIG.

FIG. 14 is a cross-sectional view showing a small-diameter portion corresponding to FIG. 13 in an end rod of a vehicle suspension arm as still another embodiment of the present invention.

[Explanation of symbols]

 12 Body Rod 18 End Rod 20 Center Rod 30 Annular Groove 32 Metal Tube

Continuing from the front page (72) Inventor Koji Uchino 3-1, Higashi 3-chome, Komaki City, Aichi Prefecture (72) Inventor Shizuo Maeda 1-3-1, Higashi 3-chome, Komaki City, Aichi Prefecture (72) ) Inventor Masanobu Kawaguchi 3-1, Higashi 3-chome, Komaki City, Aichi Prefecture F-term in Tokai Rubber Industries Co., Ltd. (reference) 3D001 AA17 DA04

Claims (9)

[Claims] 1. A metal rod in which an axial end of a second metal rod is connected and fixed to an axial end of a first metal rod, wherein the axial end of the first metal rod is provided. On the outer peripheral surface of the portion, while forming circumferential grooves continuously or discontinuously in the circumferential direction, at least two circumferentially spaced grooves,
The axial end of the second metal rod is formed in a cylindrical shape and is extrapolated to the axial end of the first metal rod. And a metal sleeve formed separately from the second metal rod is extrapolated and arranged, and the metal sleeve and the second metal rod are deformed in close contact with each other, and the second metal rod is A metal rod characterized by being fitted into and fixed to a circumferential groove of one metal rod. 2. The metal rod according to claim 1, wherein the second metal rod and the metal sleeve are made of the same material. 3. The metal rod according to claim 2, wherein the metal sleeve is thinner than a cylindrical axial end of the second metal rod. 4. The metal rod according to claim 1, wherein an axial end of the first metal rod has a solid structure. 5. A deformed portion whose outer diameter dimension changes in a circumferential direction is provided at at least a part of an externally fixed portion of the first metal rod for externally fixing the second metal rod. A metal rod according to any one of the above. 6. The first metal rod and the second metal rod are brought into close contact with each other over the entire surface of the first metal rod at a portion where the first metal rod is fitted and fixed in a circumferential groove of the first metal rod. Item 6. A metal rod according to any one of Items 1 to 5. 7. The metal rod according to claim 1, wherein the metal rod is a rod member for an automobile to which a tensile / compression load is applied in an axial direction of the first and second metal rods. 8. An axial end of the first metal rod opposite to a connection side with the second metal rod,
The metal rod according to any one of claims 1 to 7, wherein a joint portion is formed. 9. When obtaining an integral metal rod by connecting and fixing the axial end of the second metal rod to the axial end of the first metal rod, On the outer peripheral surface at the axial end,
A circumferential groove extending continuously or discontinuously in the circumferential direction,
While forming at least two spaced apart in the axial direction, the axial end of the second metal rod is cylindrical and extrapolated to the axial end of the first metal rod, and the second metal rod is The metal sleeve formed separately from the first and second metal rods is extrapolated to the axial end portion of the rod, and the metal sleeve is caulked to form the metal sleeve and the second metal rod. A method of manufacturing a metal rod, wherein the rods are plastically deformed in close contact with each other, and the second metal rod is inserted and fixed in the circumferential groove of the first metal rod.