JPS61287807A - Structure of suspension bush assembly used in suspension mechanism for vehicle - Google Patents

Abstract

PURPOSE:To improve resistance to vibration by injecting resin into a spherical sliding gap between a cylindrical fitting and a race fitting so as to mold a sliding resin member in a bush assembly used for a suspension device made of fiber reinforced resin. CONSTITUTION:A bush assembly which is fitted onto a cylindrical joint 4 of a suspension arm 2 made of fiber reinforced resin through a rubber sleeve 12, is composed of a cylindrical fitting 6, a race fitting 8, and of a sliding resin 10. In this configuration, the sliding resin 10 is formed by injection molding glass fiber reinforced resin into a gap between a spherical convex surface 16 of the cylindrical fitting 6 and a spherical concave surface 20 of the race fitting 8. This configuration is capable of providing a smooth and positive sliding motion with the provision of improved resistance to vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a suspension bush assembly structure in a vehicle suspension mechanism, and in particular incorporates a ball joint mechanism to effectively reduce twisting, twisting, and other forces applied to a suspension rod. The present invention relates to a structure of a suspension bushing assembly that improves vibration damping or isolation characteristics while simultaneously absorbing vibrations.

(Prior Art) Conventionally, suspension members such as various arms, rondos, links, etc. or suspension lofts have been made swingable in various directions in order to suspend differentials, wheels, etc. on the body of an automobile or the like. The pivot joints at both ends of the suspension rod, that is, the pivot joints to the vehicle body, axle, or wheels, are generally made of rubber material for the purpose of damping vibrations. A suspension bushing is included.

By the way, such suspension bushings generally include an inner cylinder member into which a predetermined pivot shaft is inserted for suspension of the vehicle, and a suspension bushing that is arranged concentrically at a predetermined distance outside the inner cylinder member, and The suspension rod of the suspension mechanism is fitted into the outer surface, and a cylindrical elastic member is interposed between the outer cylinder member and the attached outer cylinder member. The elastic force of the elastic member absorbs vibrations in the direction perpendicular to the axis, and the torsional deformation of the elastic member around the axis causes
Rotation of both the inner and outer cylindrical members, in other words, relative rotation between the pivot shaft fixed to the cylindrical members and the suspension rod is allowed.

However, in the conventional suspension bushings as described above, due to the elasticity, shape, size, etc. of the elastic members, the stiffness in the direction perpendicular to the axis of the bushing and the torsional rigidity around the axis, in other words, the vibration damping performance and the It has been difficult to appropriately set the rotational performance of the pivot and the suspension rod independently of each other in accordance with the characteristics required of the bushing.

In other words, in the conventional bushing structure, if the rigidity in the direction perpendicular to the axis is significantly shifted with emphasis on vibration isolation performance, the torsional rigidity around the axis will also increase, which will improve the rotation performance between the pivot and the suspension rod. Conversely, if the torsional rigidity around the axis is lowered in order to improve the rotation performance between the pivot and suspension rod, the rigidity in the direction perpendicular to the axis will also be lowered, resulting in good vibration isolation performance. The problem was that it was no longer possible to obtain

Therefore, in order to solve the problems of the above-mentioned conventional suspension bushings, the applicants of the present application proposed a combination of a cylindrical member and an elastic member in U.S. Pat. In the meantime, we have proposed a bushing assembly in which a friction reducing means (sliding sleeve) is interposed to reduce the frictional resistance between them. According to this bushing assembly, the frictional resistance between the cylindrical member and the elastic member is reduced by the sliding sleeve, and the elastic member has a rigidity in a direction perpendicular to the axis of the bushing assembly. However, it is possible to slide relatively easily around the axis relative to the opposing cylindrical member with the sliding sleeve in between, and the rotation between the pivot and suspension rod can be improved while maintaining good vibration isolation performance. This also made it possible to maintain good dynamic performance.

(Problem) However, even in the bushing assembly improved in this way, forces in directions oblique to the bushing axis direction,
When a so-called twisting force is applied, the sliding function of the sliding bushing is not fully expressed, and the applied twisting force is absorbed by an elastic member, similar to conventional bushings. This has the inherent problem that the vibration damping function of the elastic member deteriorates.

On the other hand, in order to reduce the weight of vehicles and improve corrosion resistance, attempts have been made to change the suspension rods in suspension mechanisms from conventional metal ones to resin ones. When such a suspension rod is a short dual link (arm), the above-mentioned twisting force as well as the twisting force around the axis of the bushing becomes a big problem. Absorb 1. Unless the force applied to the resin rods is reduced, it will be extremely difficult to make such suspension rods from resin.

However, in the conventional bush structure, torque and moment force due to the reaction force of the elastic member act on the rond in response to twisting or twisting input, and it is difficult for the resin to withstand this force. be.

(Solution Means) Here, the present invention has been made to solve the above-mentioned problems, and its feature is that the end of the suspension rod of the vehicle suspension mechanism is connected to the vehicle body side or the axle shaft. In the structure of a suspension bushing assembly for vibration-proof connection to a wheel side, (a) an inner cylindrical metal fitting having a spherical convex surface on the outer circumferential surface of an intermediate portion in the axial direction and into which a predetermined pivot shaft is inserted; b) a cylindrical race member having a spherical concave surface located outside the inner cylindrical metal fitting and provided at a portion corresponding to the spherical convex surface so as to form a uniform gap along the spherical convex surface; c) The race member and the inner cylindrical fitting are integrally formed by injection molding a predetermined resin material in the gap between the spherical concave surface of the race member and the spherical convex surface of the inner cylindrical fitting. (d) a sliding member that is connected to the race member and can freely slide on the spherical convex surface of the inner cylinder fitting; (d) an end of the suspension rod that is located concentrically outside the race member; interposed between the cylindrical connecting part,
The structure includes a cylindrical rubber elastic body that blocks or suppresses transmission of vibration between them.

(Operation/Effect) The suspension bushing assembly structure according to the present invention as described above includes an inner cylindrical metal fitting, a cylindrical race member,
An effective ball joint mechanism is constructed by a sliding member that is injection molded between them to integrally connect them and to be able to slide freely against the spherical convex surface of the inner cylinder fitting. Therefore, even if twisting or twisting forces are applied, they are effectively absorbed by the ball joint mechanism, which is why the ball joint mechanism is interposed between the suspension rod and the cylindrical connection at the end of the suspension rod. There is no twisting or twisting force applied to the rubber elastic body. Therefore, since no unnecessary reaction force is generated on the rubber elastic body, the damping function of the rubber elastic body can be advantageously maintained, and the force applied to the suspension rod due to twisting or twisting is reduced, and therefore, , it becomes possible to use resin for such suspension rods,
This makes it possible to advantageously achieve weight reduction, improved corrosion resistance, and the like.

In addition, in such suspension bushings and assemblies, a uniform gap is formed between the spherical convex surface of the inner cylinder fitting and the spherical concave surface of the race member located outside thereof, and the resin material is injected into the gap. This results in the formation of a spherical sliding member with a uniform thickness that allows the inner cylindrical metal fitting and the race member to slide relative to each other.
It is possible to absorb the dimensional tolerance between the race member and the inner cylinder metal fitting, and since the clearance is generated by the contraction of the resin, it is possible to obtain a ball joint structure with no play and high precision. The ball joint structure is achieved by integrally connecting the race member and the inner cylindrical fitting via the sliding member formed by molding, which has the advantage of requiring fewer machining steps. It happens.

(Example) Hereinafter, in order to clarify the present invention more specifically, one example thereof will be described in detail based on the drawings.

First, FIG. 1 shows an example of a dual link arm, which is one of the suspension rods, to which a suspension bush assembly according to the present invention is attached, and FIGS. , a cross section of the main part is shown. In those figures, 2 is an arm in a dual link suspension, which is molded using fiber reinforced resin material (FRP) and has an I wall cross section as shown in Figure 3. are doing. Also,
Arm eyes 4, 4 as cylindrical connecting portions are integrally formed at both ends of the arm 20, respectively. Then, inside this arm eye 4, an inner cylindrical metal fitting 6. Lace fittings 8
．． A bushing assembly consisting of a sliding resin 10 and a rubber sleeve 12 is attached.

By the way, as shown in an enlarged view in FIG. 4, the inner cylindrical metal fitting 6 in such a bushing assembly has a hollow portion in its axial direction as an insertion hole 14 into which a predetermined pivot shaft is inserted and attached. On the other hand, the outer peripheral surface of the intermediate portion in the axial direction is formed as a spherical convex surface 16. Incidentally, circumferential grooves 18.1B are provided near both ends of the inner cylinder fitting 6 in the axial direction, respectively, for mounting dust boots thereon.

Further, as shown in an enlarged view in FIG. 5, the race fitting 8 has a cylindrical shape with a predetermined length, and the inner circumferential surface at the axial center portion thereof is the spherical convex surface of the inner cylindrical fitting 6. It is formed as a spherical concave surface 20 having a shape corresponding to 16, so that a uniform gap can be formed along the spherical convex surface 16 when combined with the inner cylindrical metal fitting 6. Further, the spherical concave surface 20 is provided with two engagement grooves 22, 22. A gate 2 is located at the center of the spherical concave surface 20 of the race fitting 80 and passes through the cylindrical wall of the race fitting 8.
4 are provided in a suitable number (here, two) at symmetrical positions. Note that on the outer circumferential surface of both axial ends of the race fitting 8, there are grooves 26.2 into which the dust boots are fitted.
6 are provided respectively.

In order to realize an integrated ball joint mechanism by combining the inner cylinder fitting 6 and the race fitting 8 and injection molding the sliding resin 10 between them, for example, as shown in FIG. In this way, it is integrally vulcanized and molded.

That is, as shown in FIG.
The inner cylindrical metal fitting 6 and the race metal fitting 8 are held and set by an upper mold 30 and a lower mold 32 so that a predetermined gap is formed between their spherical convex surface 16 and spherical concave surface 20. Then, a predetermined resin material 34 constituting the sliding resin 10 is guided through the sprue 36 of the molding die 28, and is passed through the gate 24 provided on the race fitting 8 between the spherical convex surface 16 and the spherical concave surface 20. By injecting into the gap, the intended sliding resin 10 is molded.

Note that any material having lubricity can be used as the resin material 34 constituting the sliding resin 10, but generally a resin material such as nylon reinforced with glass fiber, carbon fiber, etc. is used. In particular, a resin such as nylon reinforced with fine charcoal fibers (0.2 to 1 μm in diameter, 5 to 30 μm in length) such as potassium titanate whiskers is advantageously used. In other words, by using such a resin material, while ensuring appropriate lubricity, it exhibits excellent characteristics such as no damage to the spherical sliding surface and no deterioration of the resin during use. .

By such injection molding operation of the resin material 34, a spherical sliding resin 10 having a predetermined thickness is formed in the gap between the spherical convex surface 16 of the inner cylinder fitting 6 and the spherical concave surface 20 of the race fitting 8. Accordingly, the inner cylinder fitting 6 and the race fitting 8 are as follows.
This results in a structure in which they are integrally connected via the sliding resin 10. In addition, in such a sliding resin 10, a desired clearance is formed on the sliding surface due to the contraction of the resin after injection. Since the gap between the two is uniform, the distance is almost constant. That is, by forming the sliding resin 10 with a substantially constant thickness within a uniform gap, it is possible to maintain a constant amount of resin contraction, and this is achieved in this way. The presence of approximately uniform rearance ensures smooth spherical sliding.

In addition, as a method for injection molding the sliding resin 10 formed between the spherical convex surface 161 and the spherical concave surface 0 of the inner cylinder fitting 6 and the race fitting 8, various methods may be used in addition to the method for the upper side. However, by injecting the resin material 34 through the gate 24 provided on the race fitting 8, as shown in FIG. Since the resin material 34 that tends to shrink inward is restrained outward, the necessary clearance can be secured between the sliding resin 10 to be formed and the spherical convex surface 16 of the inner cylindrical fitting 6. Therefore, the sliding motion of the sliding resin 10 relative to the spherical convex surface 16 is realized as a smooth motion.

Next, as shown in FIG. 7, the integral ball joint unit composed of the inner cylindrical fitting 6, the race fitting 8, and the sliding resin 10 thus obtained has a spherical sliding surface. In order to prevent deterioration of the sliding function due to the intrusion of dirt, muddy water, etc. into the contact surface between the spherical convex surface 16 and the sliding resin 10, the groove portion 26 and the inner cylindrical metal fitting 6 are formed at both ends of the race fitting 8. Annular rubber dust boots 38, 38 are respectively attached so as to straddle between the circumferential groove 18 and the circumferential groove 18.

Then, for the ball joint unit to which the dust boot 38 is attached in this way, a cylindrical rubber as shown in FIGS. A rubber sleeve 12, which is an elastic body, is press-fitted and is further press-fitted and installed into the arm eye 4 of the arm 2 as shown in FIGS. 1 and 2.

Note that lips 40 and 40 are provided on the outer periphery of both ends of the rubber sleeve 12 in the axial direction, and when the sleeve 12 is press-fitted into the arm eye 4,
Each lip 40 is brought into contact with the end surface of the arm eye 4.

Further, the rubber sleeve 12 is fixed to the race fitting 8 and the arm eye 4 by post-adhesion, if necessary.

Therefore, in the suspension bush assembly structure obtained in this way, even if twisting force or twisting force is applied to it, the suspension bushing is composed of the inner cylinder fitting 6, the race fitting 8, and the sliding resin 10. It is effectively absorbed by the pole joint mechanism, and the force applied to the resin arm 2 can be advantageously reduced, and the unnecessary reaction force of the rubber sleeve 12 caused by twisting or twisting can be eliminated, and the damping characteristics of the arm 2 can be improved. Therefore, the transmission of vibration can be effectively blocked or suppressed.

Since the force of such twisting and twisting is effectively absorbed and the force applied to the arm 2 is reduced, even if the arm 2 is made of resin, there are problems such as the arm being destroyed. Therefore, the arm 2 can be made of resin, making it possible to effectively reduce the weight of the vehicle and improve its corrosion resistance.

Although one embodiment of the present invention has been described in detail above, it is a literal illustration, and the present invention is not interpreted in any way limited by the description of the embodiment. Various changes, modifications, improvements, etc. can be made based on the knowledge of those skilled in the art without departing from the spirit of the invention, and the present invention also includes such embodiments.

Furthermore, the present invention can be advantageously applied to a vibration-proof connection structure for short suspension rods such as an arm in an upper dual-link suspension, but it is generally applicable to various types of suspension rods used in automobile suspension mechanisms. It can also be applied to connecting the ends of suspension rods, such as control arms, strut rods, radius rods, stabilizer link ronds, etc.

[Brief explanation of the drawing]

FIG. 1 is a front view of an arm with suspension bush assemblies according to the present invention attached to both ends, and FIGS. 2 and 3 are a cross-sectional view taken along the line ■-■ and a cross-sectional view taken along the line ■-■ in FIG. 1, respectively. It is a diagram. FIGS. 4 and 5 are half-cut sectional views showing the inner tube fitting and the race fitting, respectively, used in such a suspension bushing assembly, and FIG. 6 shows the inner tube fitting and the race fitting used in the suspension bushing assembly. FIG. 7 is an explanatory cross-sectional view of a mold showing one method of injection molding a sliding resin, and FIG. 7 shows an inner cylindrical fitting obtained in this manner. 8 is a half-cut sectional view of an integral pole joint unit including a race fitting and a sliding resin; FIG. 8 is a half-cut sectional view of a rubber sleeve; and FIG. 9 is a sectional view taken along line IX-IX in FIG. 8. 2 = Arm 4: Arm eye 6: Inner cylinder metal fitting 8: Race metal fitting 10: Sliding resin 12: Rubber sleeve 16: Spherical convex surface 20: Spherical concave surface 24: Gate 28: Molding mold 30. 32: Upper mold, lower mold 34 : Resin material 38: Dust boots Applicant Tokai Rubber Industries Co., Ltd. Figure 4 Figure 5 Figure 6

Claims (3)

[Claims] (1) A suspension bushing assembly structure for vibration-proofing connection of the end of the suspension rod of the vehicle suspension mechanism to the vehicle body side, axle, or wheel side, with a spherical convex surface provided on the outer peripheral surface of the intermediate portion in the axial direction. In addition, an inner cylindrical metal fitting into which a predetermined pivot shaft is inserted, and a portion located outside the inner cylindrical metal fitting corresponding to the spherical convex surface thereof are provided so as to form a uniform gap along the spherical convex surface. a cylindrical race member having a spherical concave surface; and a race member formed by injection molding a predetermined resin material into a gap between the spherical concave surface of the race member and the spherical convex surface of the inner cylindrical metal fitting. a sliding member that integrally connects the inner cylindrical metal fitting and can freely slide on the spherical convex surface of the inner cylindrical metal fitting; A vehicle suspension mechanism comprising: a cylindrical rubber elastic body interposed between a cylindrical connecting portion at an end of a suspension rod and blocking or suppressing transmission of vibration therebetween. Suspension bush assembly structure in. (2) The sliding member is formed by injecting the resin material through a gate portion provided through the cylindrical wall of the cylindrical race member, and the resin material remains in the gate portion. The suspension bushing assembly structure according to claim 1, wherein the suspension bushing assembly structure is joined to the race member. (3) The suspension bush assembly structure according to claim 1 or 2, wherein the suspension rod is made of a fiber-reinforced resin material.