JPH1148366A - Resin arm and method for manufacturing resin arm - Google Patents

Abstract

(57) [Problem] To provide a high-strength resin arm made of a synthetic resin, which is provided with a mounting portion for a joint device at an axial end. A shaft part (12) and a mounting part (14) are formed of separate parts from each other, and the shaft part (12) is made of a polyamide resin reinforced with a long fiber.
It is made of a polyamide copolymer reinforced with short fibers, comprising a polyamide 6 component of 25% by weight and a polyamide 66 component of 98 to 75% by weight, and the shaft portion 12 and the mounting portion 14 are
The desired resin arms 10 were welded and fixed to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arm made of synthetic resin as a connecting member which is stretched between predetermined members and connects the two members, and a method of manufacturing the arm, and more particularly, to a suspension constituting, for example, an automobile suspension system. The present invention relates to a high-strength resin arm suitably used as a member or the like and an advantageous manufacturing method thereof.

[0002]

2. Description of the Related Art Heretofore, as one type of a connecting member which is stretched between predetermined members to regulate relative displacement or transmit a driving force, at least one axial end of a longitudinal rod-shaped shaft is provided. It is known to have a structure provided with a mounting portion for a coupling device such as a rubber bush, a ball joint, a pillow ball bush, and the like. It is used as a connecting rod for the body.

[0003] By the way, such a connecting rod is generally formed of an iron-based metal.
Its large weight is becoming a problem. Therefore, a connecting rod made of an aluminum alloy has been proposed, but it is not practical because it is extremely difficult to satisfy cost requirements. Further, in order to achieve cost reduction and weight reduction, a connecting rod in which a shaft portion and a mounting portion are integrally formed of a synthetic resin material has been proposed, but it has been difficult to satisfy strength requirements. In order to improve the strength characteristics of the connecting rod made of a synthetic resin, it is conceivable to employ a fiber-reinforced resin. There has been a problem that it is extremely difficult to stably mold a mounting part having a complicated shape having a part, a curved part, a spherical shell part, and the like.

[0004]

Here, all of the inventions according to claims 1 to 5 have been made on the background of the above circumstances, and particularly, the inventions according to claims 1 to 3 Another object of the present invention is to provide a resin arm having an improved structure, which is lightweight, low-cost, and stably exhibits high strength characteristics under favorable manufacturability.

[0005] Further, the inventions according to claims 4 to 5 can easily provide a resin arm having an improved structure that is light in weight and stably exhibits high strength characteristics, with good manufacturability. It is an object of the present invention to provide a method of manufacturing a resin arm which can be manufactured at low cost.

[0006]

In order to solve such a problem, the present inventor has conducted detailed experiments and studies.
By independently considering the requirements required for the shaft portion and the mounting portion, all of the various characteristics required for the resin arm as one connecting member as a whole can be highly achieved. Have been newly found, and the inventions according to claims 1 to 5 have been completed based on such a new technical viewpoint.

[0007] That is, a feature of the invention as set forth in claim 1 is that in a resin arm provided with a mounting portion of a joint device at at least one axial end of a longitudinal rod-shaped shaft. The part is formed of a fiber-reinforced polyamide resin, and the mounting part is
6 to 25% by weight of polyamide 6 component and 98 to 75% by weight
The fiber length of the mounting portion is shorter than the fiber length of the shaft portion, and the shaft portion and the mounting portion are formed of a fiber-reinforced polyamide copolymer comprising a polyamide 66 component of Is a resin arm which is formed of separate parts and is welded.

In the resin arm having the structure according to the first aspect of the present invention, the shaft portion and the mounting portion are formed of different materials from each other. This has a large effect on the strength of the arm member, but the shaft, which is simple in shape and easy to mold, is made of long fiber reinforced resin. By using a short fiber reinforced resin for the mounting portion having a relatively small influence, large strength characteristics can be stably exhibited as a whole under excellent manufacturability.

In addition, the shaft portion and the mounting portion are both formed of a polyamide-based thermoplastic resin, and the mounting portion is formed of a material containing the polyamide 6 component at a specific ratio. The shaft part and the mounting part formed of the parts can be easily welded and fixed with good strength, so that good manufacturability and excellent strength properties as a whole are more advantageously and It is achieved stably. In particular, in the resin arm having the structure according to the present invention, polyamide 6 is used as the material of the mounting portion.
Since the polyamide resin containing the component and the polyamide 66 component in a specific weight ratio is employed, the strength of the member of the mounting portion and the welding strength of the shaft portion and the mounting portion can be both more highly achieved. You can. That is, when the weight ratio of the polyamide 6 component is less than 2% by weight in the material of the mounting portion, it is difficult to obtain sufficient weldability to the shaft portion, and when it is more than 25% by weight, the strength of the mounting portion is sufficiently high. It is difficult to obtain.

The specific shape such as the cross-sectional shape, size, length, etc. of the shaft is not particularly limited, but may be appropriately set according to the required strength, installation space, and the like. Since it has a solid or hollow long rod shape as a whole and does not have a complicated shape such as a tubular portion, a curved portion, and a bent portion like a mounting portion, it has a long fiber-containing resin material. Thus, good moldability can be ensured. The specific shape of the mounting portion is not particularly limited, and is determined according to the structure of the joint device to be mounted, such as a cylindrical shape or a spherical shell shape. As a result, good moldability can be ensured. The type of the coupling device is not particularly limited, and various types of coupling devices such as an elastic coupling device such as a rubber bush and a spherical sliding type coupling device such as a ball joint and a pillow ball joint can be employed.

The polyamide resin forming the shaft portion is a polymer having an amide bond in the main chain. Examples thereof include polyamide 6, polyamide 66, polyamide 12, and polyamide 12.
Alternatively, those copolymers and aromatic nylons are appropriately selected in consideration of required moldability, cost, strength, and the like.
Can be adopted. Further, as a welding structure of the shaft portion and the mounting portion, welding using a chemical or the like, welding by heating with a laser or the like is also possible, but, for example, either one of the shaft portion and the mounting portion is performed first. By molding and setting the other part in a mold of the other part to form the other part, a welding structure or the like in which the shaft part and the mounting part are welded by heat during molding of the other part is formed. Is preferably adopted.

Further, the fiber material for reinforcement in the mounting portion and the shaft portion is not particularly limited, and is appropriately determined in consideration of required properties such as strength, moldability, cost, and the like. For example, glass fiber, carbon fiber, aramid fiber or the like can be adopted as the reinforcing fiber. In addition, the length of the reinforcing fiber contained in the mounting portion and the shaft portion is also appropriately determined in consideration of the strength, shape, molding method, and the like required of the resin arm, and is particularly limited. Preferably, the contained fiber length in the mounting portion is less than 1 mm, while the contained fiber length in the shaft portion is 1 mm or more. As a result, the moldability of the mounting portion and the strength of the shaft portion are both extremely advantageously ensured. In addition, if the length of the fiber contained in the mounting portion is too short, an effective reinforcing effect may not be obtained. In addition, since the fiber length contained in the shaft portion is too long, there is a possibility that the moldability is adversely affected. Therefore, in the case of injection molding, it is preferable to set the length to 60 mm or less. Since it is possible to form a fiber longer than the length of the shaft portion while pulling it out from the reel, the fiber length can be set to the length of the entire length of the shaft portion.

Still further, preferably, as described in claim 3, the fibers contained in the shaft portion are arranged substantially in the longitudinal direction of the shaft portion. Thus, the strength of the shaft portion against the axial load can be more advantageously and stably secured, and the load resistance and reliability of the resin arm can be further improved.

The invention described in claim 4 is the first invention.
In manufacturing the resin arm according to the above, the shaft portion,
After being formed by pultrusion, the mounting part is arranged in a mold of the mounting part to form the mounting part,
The method is characterized by a method for manufacturing a resin arm that is welded to the shaft simultaneously with the molding.

According to the method of the present invention, even when a resin material containing long reinforcing fibers is employed, the moldability of the shaft portion can be advantageously ensured. It is possible to easily manufacture a high-strength shaft portion, and thus a resin arm, with good manufacturability. Moreover, since the reinforcing fibers are advantageously arranged in the longitudinal direction of the shaft portion, which is the drawing direction, by drawing the reinforcing fiber-containing resin material, the strength against the axial load on the shaft portion and thus the resin arm is further increased. Advantageously and stably, it is ensured. When the shaft portion is formed by pultruding, a shaft portion having a substantially constant cross-sectional shape in the axial direction is preferably adopted.

In addition, according to the method of the present invention, since the shaft member and the mounting portion are both formed of a polyamide resin material, when the mounting portion is formed, heat or the like of the molding resin material of the mounting portion is reduced. And the surface of the shaft member is melted, so that the mounting portion is welded to the separately formed shaft portion at the same time as the mounting portion is formed and firmly fixed, and the shaft portion is mounted. This eliminates the need for a special welding step or treatment for welding the parts to each other, and can further improve the manufacturability of the resin arm.

In the method of the present invention,
For example, a serration or a screw groove, or an uneven portion including an independent or continuous concave portion or convex portion is provided on an axial end portion of the shaft portion to which the mounting portion is attached. Providing a locking part that is locked to the uneven part,
Although it is possible to form a shape-fixing mechanism or the like, or to apply an adhesive to the surface of the axial end of the shaft, etc., particularly according to the method of the present invention, the shaft and the mounting portion are By welding, it is possible to stably obtain a large fixing strength. Therefore, it is possible to easily secure a sufficient fixing strength without employing such a troublesome shape fixing mechanism or bonding treatment. There is an advantage that can be.

It is also possible to assemble a separately formed coupling device to the mounting portion after the mounting portion is formed. In particular, when the mounting portion is fixed to the shaft simultaneously with the formation,
For example, as described in claim 5, by disposing the joint device in the mold of the mounting portion and molding the mounting portion, the joint device is formed with the molding of the mounting portion. At the same time, the manufacturing method of the resin arm to be attached to the mounting part
It is preferably adopted. According to such a manufacturing method, since a special assembling step or the like for assembling the joint device to the mounting portion becomes unnecessary, the productivity of the resin arm having the joint device can be improved. is there. In the case where a vibration isolating joint such as a rubber bush having a rubber elastic body or the like is adopted, by following the manufacturing method according to claim 5,
Simultaneously with the formation of the mounting portion and the attachment of the joint device to the mounting portion, it is also possible to apply a pre-compression to the rubber elastic body constituting the joint device, thereby improving the durability and the durability of the joint device (rubber elastic body). There is also an advantage that the assembling strength can be advantageously obtained.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 shaft 1
The two cylindrical portions 14, 14 as a pair of mounting portions are provided at both ends, and rubber bushes 16, 16 as a joint device are attached to the cylindrical portions 14, 14, respectively. ing. The suspension arm 10 is mounted between the wheel and the body by attaching one rubber bush 16 to the wheel side and the other rubber bush 16 to the body side. The suspension device is configured to be swingably connected to each other to form a suspension device.

More specifically, the shaft portion 12 has a shape of a long rod having a circular cross section. Further, the cylindrical portions 14, 14
Each has a substantially large-diameter cylindrical shape, and is integrally formed with a bottomed cylindrical fixing portion 18 which protrudes and opens radially outward at one location on the outer peripheral surface. . The fixing portion 18 is externally inserted into the axial end 32 of the shaft portion 12, and each tubular portion 14 is fixedly attached to the shaft portion 12.

As shown in FIG. 3, the rubber bush 16 has a thick cylindrical rubber elastic body 22 attached to a small-diameter cylindrical inner cylindrical fitting 20 in an extrapolated state. It has an integral vulcanized molded product in which the inner peripheral surface of the rubber elastic body 22 is vulcanized and bonded to the outer peripheral surface of the inner cylindrical metal member 20. In addition, large-diameter flange portions 24, 24 are integrally formed at both axial end edges of the rubber elastic body 22, and the outer peripheral surface is provided with a predetermined width at a portion opposed in one radial direction. A pair of cutouts 26 extending in the axial direction,
26 are provided.

The rubber bush 16 is attached to the cylindrical portion 14 in an inserted state, and a radial compressive load is applied to the rubber elastic body 22 so that the outer periphery of the rubber elastic body 22 is The surface is pressed against the inner peripheral surface of the cylindrical portion 14, and the both flange portions 24, 24 are overlapped and abutted on both axial end surfaces of the cylindrical portion 14, thereby rotating around the central axis. And axial escape is prevented. In a state where the rubber bush 16 is attached to the cylindrical portion 14, a portion facing the axial portion of the shaft portion 12 in the axial direction includes a lightening portion 26,
26 is positioned, and the radial spring ratio of the rubber bush 16 is adjusted.

Here, both the shaft portion 12 and the respective cylindrical portions 14 as described above are formed of fiber reinforced resin.

In particular, the shaft portion 12 is formed of a fiber-reinforced polyamide resin in consideration of strength, heat resistance, durability, cost performance, moldability, and the like, in addition to the weldability with the cylindrical portion 14. For example, polyamide 6, polyamide 66,
Polyamide 12, or a fiber reinforced resin containing glass fibers or the like in a polyamide 12, a copolymer thereof, or an aromatic nylon is preferably employed. The shaft portion 12 is preferably made of a long material by a continuous pultrusion method (continuous pultrusion method) in which a molten resin material containing such reinforcing fibers is continuously drawn through a die having a predetermined shape and cooled. Is manufactured by cutting the obtained long material into an appropriate length. That is, if manufactured by such a pultrusion molding method, even if long fibers are employed as the reinforcing fibers,
Good moldability and stable characteristics are advantageously ensured, and since the reinforcing fibers are arranged in the drawing direction, the strength in the shaft portion 12 can be obtained very advantageously and stably. . And the shaft portion 12
In the above, a long fiber having a fiber length of 1 mm or more is suitably adopted, whereby more excellent strength can be realized.

On the other hand, since the cylindrical portion 14 has a complicated shape having a curved portion, a protruding portion, and the like, the molten resin material is filled in a molding cavity formed by, for example, a molding die and cooled. It can be advantageously produced by an injection molding method or the like in which it is solidified. Here, as a material of the cylindrical portion 14, in consideration of strength, heat resistance, durability, cost, moldability, and the like, in addition to the weldability with the shaft portion 12, the polyamide 6 component is 2 to 25% by weight. % Polyamide 66 component at 98%
７５75% by weight of a polyamide copolymer reinforced with a fiber,
A resin material reinforced with shorter fibers than the fibers contained in the molding material of No. 2 is used. That is, by adopting a resin material reinforced with short fibers, even if the cylindrical portion 14 has a complicated shape,
It can be easily formed by an injection molding method or the like, and good moldability and stable characteristics are advantageously ensured. Then, in the cylindrical portion 14, short fibers having a fiber length of less than 1 mm are suitably adopted, whereby more excellent moldability can be achieved.

Also, particularly preferably, the cylindrical portion 14 is welded to the shaft portion 12 simultaneously with its molding. To this end, first, the shaft portion 12 is formed by pultrusion molding or the like, and the rubber bush 16 is separately formed. As shown in FIG. Then, it is set at a predetermined mounting position with respect to the cylindrical portion 14. After that, the molding die 28 is closed, and the molding cavity 30 is filled with the molding resin material of the cylindrical portion 14 by an injection operation or the like to form the cylindrical portion 14. When the shaft portion 12 is set in the molding die 28, a heating process is performed on the shaft portion 12 as necessary.

In this manner, when the cylindrical portion 14 is molded, the cylindrical portion 14 is set in the molding cavity 30 depending on the heating temperature of the cylindrical portion 14 filled in the molding cavity 30 and the heating temperature of the molding die 28. When the shaft portion 12 is heated, the surface of the shaft portion 12 is melted and covered with the molten resin material forming the cylindrical portion 14, and as a result, the shaft portion 12 and the cylindrical portion 14 are welded. It is almost integrated. In addition, based on the filling pressure of the molding resin material into the molding cavity 30 of the cylindrical portion 14 and the contraction pressure upon cooling and solidification, the cylindrical portion 14 (the fixing portion 1)
The fitting effect of 8) is also exerted, and a stronger fixing force is exerted.

That is, while the material of the shaft portion 12 is a polyamide resin, the material of the cylindrical portion 14 is 2-25% by weight of the polyamide 6 component and 9% of the polyamide 66 component.
By making the polyamide copolymer 8 to 75% by weight, the tubular portion 14 can be easily and advantageously welded to the shaft portion 12 while ensuring the strength of the tubular portion 14. Therefore, a large fixing strength is stably exhibited. If the weight ratio of the polyamide 6 component in the material of the cylindrical portion 14 is smaller than 2% by weight, it becomes difficult to sufficiently obtain the weldability of the cylindrical portion 14 to the shaft portion 12, and if it is larger than 25% by weight. Therefore, it is difficult to sufficiently obtain the strength of the cylindrical portion 14.

Incidentally, in order to confirm the welding strength of the cylindrical portion 14 made of the material according to the present invention to the shaft portion 12, the results of an experiment of welding strength evaluation using test pieces made of various materials are shown. The results are shown in Table 1 below. In such an experiment, a secondary molding resin material was formed by injection-filling a resin material into a molding cavity in which a primary molding resin material previously formed alone was set, thereby simultaneously forming the primary molding resin material. 1inch ²
A test piece welded on a flat surface having an area of was obtained, and the welding strength of the test piece was measured by pulling the primary molding resin material and the secondary molding resin material in a direction away from each other along the welding surface. The numerical unit of the measurement results shown in Table 1 is [kgf / inch ² ]. In Table 1, the materials:
A is polyamide 6 containing 30% by weight of glass fiber.
Is a fiber reinforced resin, and the material: B is 30
A fiber reinforced resin of polyamide 66 containing 15% by weight, material: C is a fiber reinforced resin containing 30% by weight of glass fiber and comprising a copolymer of 15% by weight of polyamide 6 and 85% by weight of polyamide 66. is there. From the experimental results shown in Table 1, the specific copolymer (material: C) of polyamide 6 and polyamide 66 can be used in both the primary molding resin material and the secondary molding resin material. It is recognized that a product having sufficiently larger strength characteristics than a homopolymer of polyamide 6 can be realized without a significant decrease in welding strength as compared with a case where a homopolymer of polyamide 6 is employed. In particular, by adopting such a copolymer (material: C) as the secondary molding resin material, in particular, regardless of the material of the primary molding resin material,
The fact that a large welding strength can be obtained more advantageously
Is recognized. It has been confirmed by experiments of the present inventors that the properties such as the strength of the copolymer composed of the above material: C are sufficiently superior to the homopolymer of the polyamide 6.

[0031]

[Table 1]

If the above-described manufacturing method is adopted,
When the cylindrical portion 14 is molded, the outer peripheral surface of the rubber elastic body 22 is radially pre-compressed by the filling pressure of the molding resin material into the molding cavity 30 and the contraction pressure at the time of cooling and solidification. 16 is assembled to the cylindrical portion 14 with a good holding force.

Therefore, according to the manufacturing method as described above, the cylindrical portion 14 does not require any special steps or treatments such as shaping or bonding for fixing the shaft portion 12 and the cylindrical portion 14. At the same time as the molding of the cylindrical portion 14, the separately formed shaft portion 12 can be firmly welded and fixed to the cylindrical portion 14. At the same time, the rubber bushing can be performed without any special process. 16 can be assembled to the tubular portion 14 with an appropriate precompression.

In the suspension arm 10 thus obtained, since both the shaft portion 12 and the cylindrical portion 14 are made of synthetic resin, the suspension arm 10 is extremely lightweight and inexpensive. A large strength can be advantageously secured by the shaft portion 12 formed of the long fiber reinforced resin, and the cylindrical portion 14 is formed of the short fiber reinforced resin as a separate component from the shaft portion 12, Good strength and manufacturability can be ensured, and since the shaft portion 12 and the cylindrical portion 14 are firmly fixed by welding, extremely excellent strength against an axial tensile load and the like. Can be obtained.

Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention is not to be construed as being limited in any way by the specific structure or specific description in the embodiment. Instead, the present invention can be implemented in an embodiment in which various changes, modifications, improvements, and the like are made based on the knowledge of those skilled in the art, and unless such an embodiment departs from the spirit of the present invention. It goes without saying that both are included in the scope of the present invention.

[0036]

As is apparent from the above description, in the resin arm having the structure according to the first to third aspects of the present invention, both the shaft portion and the mounting portion are made of a synthetic resin material reinforced with fibers. Because it is formed, as a whole, it is lightweight and inexpensive, and excellent performance is stably exhibited,
In particular, a shaft portion made of a polyamide resin reinforced with long fibers and a mounting portion made of a specific polyamide copolymer reinforced with short fibers are adopted, and the shaft portion and the mounting portion are welded and fixed. In addition, a sufficient fixing strength between the shaft portion and the mounting portion is ensured, and a resin arm having excellent load bearing performance can be advantageously realized.

Further, according to the method of the present invention described in claims 4 and 5, the resin arm having the structure according to the invention of claim 1 can be advantageously manufactured. Since the long fibers can be advantageously arranged in the longitudinal direction of the shaft portion by pultruding the portion, more excellent strength is stably exhibited, and the welding of the shaft portion and the mounting portion is performed by a special process. There is an advantage that it can be advantageously performed at the same time as the formation of the mounting portion without the need for.

[Brief description of the drawings]

FIG. 1 is a partially cutaway plan view showing a suspension arm as one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of the suspension arm shown in FIG.

FIG. 3 is a longitudinal sectional view showing a rubber bush constituting the suspension arm shown in FIG. 1 by a cut surface corresponding to a III-III section in FIG. 1;

FIG. 4 is an explanatory diagram for explaining a manufacturing process of the suspension arm shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Suspension arm 12 Shaft part 14 Cylindrical part 16 Rubber bush

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI B29K 105: 08

Claims (5)

[Claims] 1. A resin arm provided with a mounting portion for a joint device at at least one axial end of a longitudinal rod-shaped shaft, wherein the shaft is formed of a fiber-reinforced polyamide resin. And the mounting portion is 2 to 25% by weight.
Of polyamide 6 component and 98 to 75% by weight of polyamide 6
It is formed by a fiber-reinforced polyamide copolymer composed of six components, and the contained fiber length in the mounting portion is:
A resin arm, wherein the length of the fiber contained in the shaft portion is shorter than that of the shaft portion, and the shaft portion and the mounting portion are formed as separate components and welded. 2. A fiber length contained in the mounting portion is less than 1 mm, while a fiber length contained in the shaft portion is 1 mm.
2. The resin arm according to claim 1, wherein the diameter is not less than mm. 3. The resin arm according to claim 1, wherein the fibers contained in the shaft portion are arranged substantially in the longitudinal direction of the shaft portion. 4. When manufacturing the resin arm according to claim 1, the shaft portion is formed by pultrusion molding, and then disposed in a molding die of the mounting portion to form the mounting portion. ,
A method for manufacturing a resin arm, wherein the mounting portion is welded to the shaft simultaneously with molding. 5. The mounting device according to claim 1, wherein the joint device is disposed in a molding die of the mounting portion, and the mounting portion is molded, so that the joint device is assembled to the mounting portion simultaneously with the molding of the mounting portion. 5. The method for manufacturing a resin arm according to item 4.