JPS628805A - Suspension bushing assembly in vehicle suspension mechanism and its manufacture - Google Patents

Abstract

PURPOSE:To improve twist and distortion absorbing capability by interposing a sliding plastic member having a sliding piece between a metal cylinder having a spherical convex surface and a cylindrical race member having a spherical concave surface and arranging a cylindrical rubber elastic body around the race member. CONSTITUTION:A bushing assembly 13 is composed of a metal cylinder 6 having in its middle section a spherical convex surface 16, a metal race 8 having a spherical convex surface 20 corresponding to the spherical convex surface 16, and a sliding plastic member 10 having a sliding piece 11 of low friction coefficient on the side to the convex surface 16 and interposed between the spherical convex surface 16 and the spherical concave surface 20 by injection molding or the like. Further, a cylindrical rubber sleeve 12 is arranged around the metal race 8 to insulate vibrations between connecting part of a suspension arm 2. With this constitution, the metal cylinder and the metal race can slide smoothly due to the spherical surface and the sliding piece 11 so that twist and distortion are effectively absorbed and the forces on the arm can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a suspension bushing assembly in a vehicle suspension mechanism and a method for manufacturing the same. The present invention relates to a suspension bushing assembly that effectively absorbs force and has improved vibration damping or isolation characteristics, and a method for manufacturing the same.

(Prior Art) Conventionally, suspension members such as various arms, rondes, links, etc. or suspension rods have been made swingable in various directions in order to suspend differentials, wheels, etc. to 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 a suspension bush generally includes an inner cylinder member into which a predetermined shaft member is inserted for suspension of the vehicle, and a concentric arrangement arranged outside the inner cylinder member at a predetermined interval, and A configuration is adopted in which a suspension rod of a vehicle suspension mechanism is fitted onto an 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 perpendicular to the axis, and the torsional deformation of the elastic member around the axis prevents the rotation of both the inner and outer cylinder members. Relative rotation between the pivot shaft fixed to the member 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 The rotation performance of the pivot and the suspension rod is determined, and it has been difficult to appropriately set the vibration isolation performance and rotation performance independently of each other according to 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 increased with emphasis on vibration isolation performance, the torsional rigidity around the axis is also increased (thus, the rotation between the pivot and the suspension rod is increased). On the other hand, if the torsional rigidity around the axis is lowered in order to improve the rotational performance between the pivot and the suspension rod, the rigidity in the direction perpendicular to the axis will also be lowered, resulting in better protection. There was a problem that vibration performance could no longer be obtained.

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 such a 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 large rigidity in the direction perpendicular to the axis of the bushing assembly. Regardless of this, it is possible to slide relatively easily around the axis relative to the cylindrical member facing the sliding sleeve, which maintains good vibration-proofing performance while maintaining the axis and suspension rond. This makes it possible to maintain good rotational 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 sleeve is not fully expressed, and the elastic member absorbs the twisting force, as with conventional bushings. There is an inherent problem that the vibration damping function of such an elastic member is degraded.

On the other hand, in order to reduce the weight of vehicles and improve corrosion resistance, attempts have been made to change the suspension ports and rads in suspension mechanisms from conventional metal ones to resin ones. In particular, when such a suspension rod is a short dual link (arm), etc., the twisting force around the axis of the bushing and the above-mentioned twisting force become a big problem. It is extremely difficult to make such a suspension mechanism made of resin unless the force is absorbed and the force applied to the resin rod is reduced.

However, in the conventional bush structure, when twisting or twisting occurs, large torque and moment forces act on the rond based on the reaction force of the elastic member.

(Solution Means) Here, the present invention provides a suspension bushing assembly capable of solving the above-mentioned problems and a suitable manufacturing method thereof. First, the features of the bushing assembly are as follows. , a suspension bushing assembly for vibration-proofing connection of the end of the suspension rod of a vehicle suspension mechanism to the vehicle body side or the axle or wheel side, (a) a spherical convex surface is provided on the outer circumferential surface of the intermediate portion in the axial direction; , an inner cylindrical metal fitting into which a predetermined pivot shaft is inserted, and (b) a spherical concave surface located on the outside of the inner cylindrical metal fitting and formed on the inner circumferential surface of an axially intermediate portion corresponding to the spherical convex surface. , and (C) a cylindrical race member forming a uniform gap along the spherical convex surface between the spherical concave surface and the spherical convex surface of the inner cylinder fitting; Provided between the spherical convex surface of the inner cylindrical fitting and integrally fixed to the spherical concave surface of the race member on the outer circumferential surface, and slidably holding the spherical convex surface of the inner cylindrical fitting on the inner periphery. (d) a spherical and annular sliding member made of a predetermined synthetic resin material and having a uniform wall thickness;
(e) an annular cloth member having a low coefficient of friction that is integrally joined to the inner circumferential surface of the sliding member; It is configured to include a cylindrical rubber elastic body that is interposed between the connecting part and blocks or suppresses the transmission of vibrations therebetween.

Further, the gist of the method of the present invention for manufacturing such a bushing assembly is that an inner cylindrical metal fitting having a spherical convex surface on the outer circumferential surface of the intermediate portion in the axial direction and into which a predetermined pivot shaft is inserted; A cylindrical race member having a spherical concave surface on the inner circumferential surface of the intermediate portion is arranged such that the spherical concave surface and the spherical convex surface face each other with a predetermined gap, and a low When an annular cloth member having a coefficient of friction is positioned in the gap surrounding the spherical convex surface of the inner cylinder member, the gap between the spherical concave surface of the race member and the spherical convex surface of the inner cylinder fitting is By injecting a predetermined synthetic resin material into the gap, a material having a substantially constant thickness is fixed to the spherical concave surface of the race member on the outer circumferential surface, and the cloth member is integrally joined on the inner circumferential surface. forming a sliding member and slidably holding the spherical convex surface of the inner cylinder fitting on the sliding member via the cloth member;
Thereafter, a cylindrical rubber elastic body interposed between the outer peripheral surface of the sliding member and the cylindrical connecting portion at the end of the suspension rod is concentrically attached.

(Operation/Effect) In the suspension bushing assembly according to the present invention, the inner cylindrical metal fitting, the cylindrical race member, and the cylindrical race member, which is injection molded between them, slides on the spherical convex surface of the inner cylindrical metal fitting. An effective ball joint II structure is constructed by the sliding member held movably. Therefore, even if twisting or twisting forces act on the ball joint mechanism, they are effectively absorbed by the rubber elastic body interposed between the cylindrical connection part at the end of the suspension rod. On the other hand, no twisting or straining force is applied. 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. Therefore, such a suspension rod can be made of resin, and it is possible to advantageously achieve weight reduction and improved corrosion resistance.

Moreover, since a cloth member with a small coefficient of friction is integrally joined to the inner surface of the sliding member, the spherical convex surface of the inner cylinder fitting is more easily held between them than when the sliding member directly holds the convex surface. It also has the advantage of reducing sliding resistance.
Furthermore, since the inner cylindrical metal fitting is held through the cloth member, fiber reinforced resin such as glass fiber reinforced resin is used as the synthetic resin material of the sliding member.
Another advantage is that the allowable load in the axial direction can be increased. In other words, if an attempt is made to directly hold the inner tube fitting with a sliding member made of fiber-reinforced resin, the spherical convex surface of the inner tube fitting may be damaged due to the presence of fibers, or the sliding resistance between them will be significant. However, there are problems such as increase in
In the present invention, it is possible to enjoy the effects of employing fiber-reinforced resin without the problems caused by the presence of such fibers.

Further, according to the manufacturing method according to the present invention, the lace member, the inner cylindrical metal fitting, and the cloth member are respectively arranged with a predetermined positional relationship, and under the arrangement state, the spherical concave surface of the lace member and the spherical convex surface of the inner cylindrical fitting By injecting a synthetic resin material into the gap between the parts, the spherical convex surface of the inner cylinder fitting can be slidably held on the inner peripheral surface, and the sliding member can be easily joined to the spherical concave surface of the race member on the outer peripheral surface. This has the advantage that the suspension bushing assembly described above can be manufactured at low cost. Also, like that,
Since the sliding member is manufactured by injection molding, it is possible to absorb the dimensional tolerances of the race member and the inner cylinder metal fitting, and since the appropriate clearance is created by the contraction of the resin, it is possible to create a highly accurate ball with no play. There is also the advantage that a joint mechanism can be obtained. Furthermore, since a synthetic resin-impregnated cloth member having a low coefficient of friction is employed, there is an advantage that the cloth member can be reliably and firmly bonded to the sliding member.

(Example) Hereinafter, in order to clarify the present invention more specifically,
One embodiment 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 cross section as shown in Figure 3. are doing.

Furthermore, arm eyes 4.4 as cylindrical connecting portions are integrally formed at both ends of the arm 2, respectively. Then, inside this arm eye 4, an inner cylindrical metal fitting 6. Lace fittings 8. Sliding resin 10. A bushing string solid body 13 consisting of a sliding cloth 11 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 of the bushing assembly 13 has an axial hollow portion formed with 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, near both ends of the inner cylinder fitting 6 in the axial direction, there are circumferential grooves 18 and 1 for attaching dust boots, respectively.
8 is provided.

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. formed as a spherical concave surface 20 having a slightly larger diameter than 16;
When combined with the inner cylinder metallic odor, uniform gaps can be formed along the spherical convex surface 16. Further, the spherical concave surface 20 is provided with two annular grooves 22 and 22 around the axis of the race fitting 8. A suitable number (two in this case) of gates 24 are provided at the center of the race fitting 8 and the spherical concave surface 20 and passing through the cylindrical wall of the race fitting 8 at equal intervals. There is. Note that grooves 26 and 26 for fitting the dust boots are provided on the outer circumferential surface of both axial ends of the race fitting a, respectively.

In order to combine such an inner cylinder fitting 6 and a race fitting 8 to form a sliding resin lO with a sliding cloth 11 bonded therebetween, for example, FIGS. Injection molding is performed as shown in FIG.

That is, first, as shown in FIG. 6, the inner cylindrical fitting 6 and the race fitting 8 are placed in a predetermined molding die 28 with a predetermined gap formed between their spherical convex surface 16 and spherical concave surface 20. The upper mold 30 and the lower mold 32 hold the mold concentrically and center the mold so that it is centered. At this time, as shown in FIG. 8, the sliding cloth 11 is sewn into a cylindrical shape (ring shape) having approximately the same diameter as the inner tube fitting 60 and the spherical convex surface 16 by sewing both ends together, with the sewn portion facing outward. In this state, it is inserted onto the spherical convex surface 16 of the inner cylinder fitting 6.

Note that the spherical concave surface 20 of the race fitting 8 is subjected to an adhesive treatment in advance. Moreover, here, as the sliding cloth 11,
Too-to made of low friction coefficient material such as PTFE (tetrafluoroethylene resin).

Yarns of about OO denier, preferably about 400 denier, are used at a density of about 20 to 200 threads per inch, preferably about 50 to 60 threads per inch, such as plain weave, twill weave,
Fabrics with a satin weave or the like will be adopted, and more preferably, in order to improve bonding properties with the sliding resin IO, these fabrics are coated with epoxy resin, urethane resin, phenol resin, acrylic resin, etc. In this way, if the sliding cloth 11 is impregnated with a synthetic resin in advance, the bondability with the sliding resin 10 is improved. , the bonding described below is performed reliably and firmly.

In such a state, as shown in FIG. 7, 2. -2
Ru. As such, the predetermined resin material 3 constituting the sliding resin 10
4 through the sprue 36 of the molding die 28 and from the gate 24 provided on the race fitting 8 into the gap between the spherical convex surface 1.6 (actually, the sliding cloth 11) and the spherical concave surface 20. Make it eject.

Note that various materials such as nylon can be used as the resin material 34 constituting the sliding resin 10, but it is possible to increase the mechanical strength of the sliding resin 10, In order to increase the permissible load in the axial direction, resin materials reinforced with glass fibers, carbon fibers, aromatic polyamide (Kevlar) fibers, etc. are generally used, which are mixed at a ratio of about 20 to 50% by weight. That will happen.

By such an injection molding operation of the resin material 34, a sliding resin of a predetermined thickness is integrally fixed to the spherical concave surface 20 of the race fitting 8 on the outer peripheral surface, and the sliding cloth 11 is integrally joined to the inner peripheral surface. 10 is formed, whereby the inner cylinder fitting 6 and the race fitting 8 are integrally connected via the sliding resin 10. Also, like that, the sliding resin 1
While the sliding cloth 11 is integrally joined to the inner peripheral surface of 0,
As the sliding resin 10 (resin material 34) shrinks after injection, a uniform clearance is formed on the sliding surface. Smooth spherical sliding is ensured between the spherical convex surface 16 and the spherical convex surface 16. That is, the gap between the spherical convex surface 16 and the spherical concave surface 20 is made uniform, so that the amount of contraction of the sliding resin 10 is approximately uniform, while the sliding resin 10 is fixed to the spherical concave surface 20 on the outer peripheral surface. Since it is,
A substantially uniform clearance is formed between the sliding cloth 11 bonded to the inner peripheral surface of the sliding resin 10 and the spherical convex surface 16, and as a result, good spherical sliding without play can be obtained. be.

In addition, injection molding of the sliding resin 10 can be carried out by various methods other than the upper one, but when a fiber-reinforced resin with poor fluidity is used as the resin material 34, this injection molding method is not suitable. As in the example, it is desirable to provide a gate 24 that penetrates the cylindrical wall of the race fitting 8 at the center of the spherical concave surface 20, and to inject the resin material 34 through the gate 24. In addition, in order to prevent the sliding cloth 11 from shifting,
It is desirable to perform injection through the gate 24 provided through the cylindrical wall of the race fitting 8. Furthermore, if the resin material 34 is injected through the gate 24 formed on the spherical concave surface 20, the sliding resin 10 (resin material 34) is constrained to the outside, so
This is also advantageous in securing clearance on the sliding surface.

Next, the inner cylindrical metal fitting 6. and the race metal fitting 8. thus obtained. As shown in FIG. 9, the integral ball joint unit consisting of the sliding resin 10 and the sliding cloth 11 has a spherical sliding surface (abutment between the spherical convex surface 16 and the sliding resin 10). In order to prevent deterioration of the sliding function due to the intrusion of dirt, muddy water, etc. to An annular rubber dust boot 38.38 is fitted respectively.

Then, for the ball joint unit to which the dust boots 38 and 38 are attached in this way, the outer circumferential surface of the lace fitting 8 located on the outer circumference of the ball joint unit is attached as shown in FIGS. 1.0 and 11. A rubber sleeve 12, which is a cylindrical rubber elastic body, is press-fitted to form a bushing assembly 13. And, such a bushing assembly 1
3, as shown in FIGS. 1 and 2, the arm eye 4 of the arm 2 is located on the outer peripheral surface of the rubber sleeve 12.
It will be press-fitted and installed. Note that the rubber sleeve 12 has lips 40 and 40 on the outer periphery of both ends in the axial direction.
are respectively provided, 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.

In the suspension bushing assembly 13 obtained in this way, the inner cylindrical metal fitting 6 and the race metal fitting 8 smoothly move between the spherical convex surface 16 and the inner circumferential surface of the sliding resin 10, that is, the sliding cloth 11. Since it is possible to slide on a spherical surface, even if twisting force or twisting force acts between them, the twisting force or twisting force will be effectively absorbed by the above-mentioned spherical sliding. Therefore, the force applied to the resin arm 2 is advantageously reduced. Further, unnecessary reaction force of the rubber sleeve 2 caused by twisting or twisting is eliminated, and the damping characteristics of the arm 2 are improved, so that vibration transmission is 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, and it is possible to effectively reduce the weight of the vehicle, improve corrosion resistance, etc.

Further, a sliding cloth 11 having a low coefficient of friction is integrally joined to the inner peripheral surface of the sliding resin 10, and the sliding resin 10 is attached to the sliding cloth 11.
Since the spherical convex surface 16 of the inner cylindrical metal fitting 6 is held through the spherical convex surface 16, even when fiber-reinforced resin is used as the resin material 34, problems such as damage to the spherical convex surface 16 and increase in frictional resistance can be avoided. Therefore, there is an advantage that the allowable amount of load applied in the axial direction can be increased without causing a decrease in sliding performance.

Although the embodiments of the present invention have been described in detail above,
This is a literal illustration, and the present invention is not to be construed as being limited by the description of such an example.
The present invention includes, without departing from the spirit of the present invention,
Various changes, modifications, improvements, etc. can be made based on the knowledge of those skilled in the art, and the present invention includes such embodiments.

Although the present invention can be advantageously applied to a bushing assembly as a vibration-proof connection mechanism for a short suspension rod such as an arm in an upper dual-link suspension, it is generally applicable to a suspension mechanism of an automobile. The invention can also be applied to bush assemblies used to connect the ends of various suspension rods used in, for example, controls, roll 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 bushing assemblies according to the present invention attached to both ends thereof, and FIGS. 2 and 3 are cross-sectional views taken along the line ■--■ and ■-■ in FIG. 1, respectively. FIG. FIG. 6 and 7 are cross-sectional explanatory views for explaining an example of the injection molding operation of the sliding resin in the bushing assembly of FIG. 1, respectively. FIG. 8 is an explanatory plan view showing the sliding cloth of the bushing assembly of FIG. 1. Figure 9 is the bush of Figure 1, and the first
FIG. 1 is a sectional view taken along the line XI-XI in FIG. 10. 2: Arm 4: Arm eye 6: Inner cylinder metal fitting 8: Race metal fitting 10: Sliding resin 11: Sliding cloth 12: Rubber sleeve 13: Push assembly 16: Spherical convex surface 20: Spherical concave surface 24: Gate 28: Molding mold 30: Upper mold 32: Lower mold 34: Resin material 38: Dust boots Applicant: Tokai Rubber Industries, Ltd. Figure 6 Figure 7 Figure 95A

Claims (4)

[Claims] (1) A suspension bushing assembly 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, and having a spherical convex surface on the outer peripheral surface of the intermediate portion in the axial direction; It has an inner cylindrical metal fitting into which a predetermined pivot is inserted, and a spherical concave surface located on the outside of the inner cylindrical metal fitting and formed on the inner circumferential surface of an axially intermediate portion corresponding to the spherical convex surface, and A cylindrical race member that forms a uniform gap along the spherical convex surface between the concave surface and the spherical convex surface of the inner cylindrical fitting; and between the spherical concave surface of the race member and the spherical convex surface of the inner cylindrical fitting. A predetermined, substantially constant wall thickness, which is integrally fixed to the spherical concave surface of the race member on the outer circumferential surface and slidably holds the spherical convex surface of the inner cylinder fitting on the inner circumferential surface. a spherical and annular sliding member made of a synthetic resin material; an annular cloth member having a low coefficient of friction and integrally joined to the inner peripheral surface of the sliding member; and an outer side of the race member. a cylindrical rubber elastic body that is attached concentrically to the suspension rod and interposed between the suspension rod and the cylindrical connecting portion at the end of the suspension rod to block or suppress transmission of vibration therebetween; A suspension bushing assembly in a vehicle suspension mechanism, comprising: (2) The sliding member is inserted into the gap between the spherical concave surface of the race member and the spherical convex surface of the inner cylindrical metal fitting through a gate portion provided by penetrating the cylindrical wall of the cylindrical race member. The suspension bushing assembly according to claim 1, wherein the suspension bushing assembly is formed by injecting the synthetic resin material. (3) an inner cylindrical metal fitting having a spherical convex surface on the outer circumferential surface of the intermediate portion in the axial direction, into which a predetermined pivot is inserted; and a cylindrical race member having a spherical concave surface on the inner circumferential surface of the intermediate portion in the axial direction; The spherical concave surface and the spherical convex surface are arranged to face each other with a predetermined gap therebetween, and an annular cloth member impregnated with a predetermined synthetic resin and having a low coefficient of friction is inserted into the inner cylindrical member within the gap. By injecting a predetermined synthetic resin material into the gap between the spherical concave surface of the race member and the spherical convex surface of the inner cylinder fitting, the spherical convex surface of the race member is positioned so as to surround the spherical convex surface of the race member. A sliding member having a substantially constant thickness is fixed to the spherical concave surface of the race member, and the cloth member is integrally joined to the inner peripheral surface of the race member, and the spherical convex surface of the inner cylinder fitting is fixed to the cloth member. A cylindrical rubber elastic member is slidably held on the sliding member via a member, and then interposed between the outer peripheral surface of the sliding member and the cylindrical connecting portion at the end of the suspension rod. A method for manufacturing a suspension bush assembly in a vehicle suspension mechanism, which is characterized in that the body is attached concentrically. (4) The synthetic resin material injected into the gap between the spherical concave surface of the race member and the spherical convex surface of the inner cylinder fitting is a fiber-reinforced resin, and the synthetic resin material is injected into the cylinder of the race member. 4. The manufacturing method according to claim 3, wherein the manufacturing method is carried out through a gate provided through a wall.