JP2000094920A - Strut type suspension device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a strut type suspension device capable of properly giving desired lateral force to a strut by a compression coil spring in a simple structure. SOLUTION: A compression coil spring 5 is formed so as to curve a coil axis passing through the center of an upper side seat surface of the compression coil spring 5 by prescribed curvature in a free condition. A rubber block 20 is interposed between an element wire 5a of a lower side end coil part positioned outside a car body in the compression coil spring 5 and an element wire 5b adjacent to this element wire 5a. The compression coil spring 5 is arranged between upper/lower side seats 3, 4 so as to surround a strut 2, to be held in a manner wherein the curve direction of the coil axis of the compression coil spring is in the car body outside direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strut-type suspension system for a motor vehicle in which a compression coil spring is arranged so as to surround a strut, and more particularly to a strut-type suspension system capable of smoothly damping struts.

[0002]

2. Description of the Related Art Various types of suspension systems for automobiles have been known, but a strut type suspension system using a shock absorber (buffer) as a strut for positioning wheels. Is widespread. In this strut type suspension device, since a displacement between the load input shaft and the strut shaft is inevitable, a bending moment is generated in the strut, and the lateral force acting on the guide portion and the piston portion of the strut makes the strut a smooth shock absorber. Smooth sliding operation is hindered. In order to prevent this, for example, a technique of offsetting a bending moment by offsetting a coil axis of a cylindrical compression coil spring with respect to a strut axis is used.

With respect to such a strut type suspension,
For example, Japanese Utility Model Publication No. 48-39290 discloses a method for reducing the lateral force generated on a buffer strut.
A method of mounting a general-purpose coil spring having a coil axis formed in a straight cylindrical shape in a free state by bending it in a direction substantially perpendicular to the center of the spring, and a coil spring previously formed by bending the center of the spring in a free state There has been proposed a method of obtaining a moment due to a lateral reaction force of a spring by setting the spring center in a mounted state so that the center of the spring is linear. Eventually, the coil spring is elastically deformed in a direction substantially perpendicular to the center of the spring and mounted with a lateral load, and the coil spring acts against the moment due to the lateral load against the moment due to the reaction force of the road surface. So as to reduce the lateral force of the bush and the piston of the shock-absorbing column.

[0004] Similarly, in British Patent No. 1 198713, a method for compressing and mounting a coil spring in a strut-type suspension device to a shock absorber or strut so that a bending moment is generated in a direction opposite to a bending moment by a wheel. Has been proposed. FIG.
No. 2 discloses a coil spring wound around a substantially linear axis, and winding portions at both ends are formed to bend by α ° with each other. This coil spring is located between the shock absorber housing and the parallel plate connected to the rod.
If the surface including both ends of the coil spring intersects on the inside of the vehicle, the compression amount of the coil spring will be larger on the outside than on the inside, so the urging force will cause the strut to exert a bending moment on the strut by the wheel. It states that a bending moment is generated in a direction opposite to the above.

[0005] Fig. 3 of the publication discloses a coil spring wound around one arc-shaped axis in a free state and formed so that two seating surfaces are inclined with respect to each other. It is described that if this coil spring is interposed between the parallel plates and is disposed so that the longer side surface faces the outside of the vehicle in a free state, the compression amount of the coil spring is larger on the outside than on the inside. ing. FIG. 4 also shows that two plates are connected to the housing and rod of the shock absorber such that the two surfaces are inclined with respect to each other, and the two surfaces intersect outside the vehicle. It is described that a cylindrical coil spring wound around is disposed. This describes that the compression amount of the coil spring is larger on the outside than on the inside.

[0006] Further, Japanese Patent No. 2642163 discloses that
In a strut-type suspension system, when the tire width of an automobile increases, the wheel support point shifts outward, so that the angle between the support action line at which the spring force action line should be set and the shock absorber axis increases, which satisfies this. In view of the fact that it is not possible to adopt a structure, a compression coil spring whose spring center line extends substantially in an S-shape in a no-load state with the aim of enabling the lateral force generated on the piston rod of the shock absorber to be largely removed is provided. Suspensions have been proposed.

[0007]

With the demand for further miniaturization of the strut-type suspension system, the improvement of the strut and its supporting mechanism using a normal cylindrical compression coil spring is not enough. It is difficult to cancel the bending moment generated in the strut. Therefore, it is necessary to positively increase the lateral force of the compression coil spring and properly attach the compression coil spring to the strut type suspension. However, in the structure disclosed in the above-mentioned Japanese Utility Model Publication No. 48-39290, in which a coil spring formed by bending a spring center in a free state is set so that the spring center is linear in a mounted state, a desired effect is obtained. It is very difficult to get.

On the other hand, in the suspension device disclosed in British Patent No. 1198713, the structure of a coil spring is disclosed. However, a desired effect can also be obtained by the coil spring and its mounting structure described in the publication. It is difficult to get. In this regard, the above-mentioned Patent No. 2642163 is disclosed.
In the publication, it is difficult to sufficiently reduce the lateral force acting on the guide portion and the piston portion of the strut. However, the compression coil spring disclosed in Japanese Patent No. 2642163, in which the spring center line extends substantially in an S-shape in a no-load state, is difficult to manufacture and causes an increase in cost.

[0009] After all, simply bending the compression coil spring as described above shifts the spring reaction force axis (spring force action line) parallel to the coil axis (spring center line), and the upper seat of the compression coil spring. Since it does not pass through the center of the surface, an eccentric force is generated with respect to the upper seat, which may adversely affect the support structure of the upper seat.

Accordingly, an object of the present invention is to provide a strut type suspension device which has a simple structure and can appropriately apply a desired lateral force to a strut by a compression coil spring.

[0011]

According to a first aspect of the present invention, there is provided a lower body seat for supporting an upper end of a strut on a vehicle body and fixing the strut to the strut. A strut-type suspension device in which a compression coil spring is arranged so as to surround the strut between the strut and the vehicle body via the strut. The compression coil spring is formed so that a coil axis passing through the center of the compression coil spring is curved at a predetermined curvature in a free state of the compression coil spring, and is located outside the vehicle body of the compression coil spring and near the lower seat. An elastic member is interposed between adjacent wires, and / or an elastic member is interposed between adjacent wires near the upper seat, which is located inside the vehicle body of the compression coil spring, and The compression coil spring disposed between the side seat and the upper seat, in which the bending direction of the coil axis was decided to retain so that the outboard direction. For example, when arranging the compression coil spring so that the coil axis is offset with respect to the strut,
The compression coil spring having the elastic member interposed therebetween may be held such that a bending direction of the coil shaft coincides with an offset direction with respect to the strut when the compression coil spring is disposed.

In particular, as described in claim 2, the upper end of the strut is supported on the vehicle body, and the strut is surrounded between a lower seat fixed to the strut and an upper seat supported on the vehicle body. In the strut type suspension device in which the compression coil spring is arranged so as to support the wheel on the vehicle body via the strut, the coil axis passing through the center of the upper seat surface of the compression coil spring is in the free state of the compression coil spring. The compression coil spring is formed so as to be curved at a predetermined curvature, and a wire of a lower end turn portion located outside the vehicle body of the compression coil spring is adjacent to a wire of the lower end turn portion. An elastic member is interposed between the
The compression coil spring disposed between the lower seat and the upper seat may be configured to be held such that a bending direction of the coil shaft is directed to the outside of the vehicle body.

According to a third aspect of the present invention, the elastic member has a central angle of 6 around the axis of the compression coil spring.
It is preferable that the lower end winding portion be constituted by a rubber block disposed so as to be in contact with the element wire of the lower end winding portion and an element wire adjacent to the lower end winding portion within a range of 5 ° or less.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an overall configuration of an embodiment of a strut type suspension device (hereinafter, simply referred to as a suspension device). FIG. 2 is an enlarged sectional view showing an upper seat 3, a lower seat 4, and a strut mount 10. 1, an upper end of a strut 2 is elastically supported by a vehicle body 1, an upper seat 3 is supported by the vehicle body 1, and a lower seat 4 is fixed to an intermediate portion of the strut 2. A compression coil spring 5 is provided between the upper seat 3 and the lower seat 4 so as to surround the strut 2.
Is arranged. The lower end of the strut 2 is fixed to a knuckle 6, and the knuckle 6 is pivotally connected to the vehicle body 1 via a lower arm 7. Thus, the wheel 8 supported by the knuckle 6 is supported by the vehicle body 1 via the strut 2 and the compression coil spring 5, and is supported by the vehicle body 1 via the lower arm 7. The upper end of the strut 2 and the upper seat 3 are attached to the vehicle body 1 via a strut mount 10, which will be described later.

The strut 2 includes a cylinder 2a and a rod 2b slidably supported in the cylinder 2a.
These constitute a shock absorber.
The upper end of the rod 2b is attached to the vehicle body 1 via a strut mount 10, and the lower end of the cylinder 2a is
, For example, the above-mentioned Japanese Utility Model Publication No. 48-39290.
It is configured in the same manner as the mechanism disclosed in Japanese Patent Application Laid-Open Publication No. H10-209,878. The lower seat 4 is fixed to the cylinder 2a between them.

As shown in FIG. 2, the compression coil spring 5 is formed such that a coil axis CA passing through the center of the upper seat surface US is curved at a predetermined curvature in a free state of the compression coil spring 5. It has an initial body bending with a bending amount d.
When the compression coil spring 5 is mounted on the vehicle body, an elastic member of the present invention is provided between the element wire 5a of the lower end turn located outside the vehicle body and the element wire 5b adjacent to the element wire 5a. A barrel rubber block 20 is interposed.

As shown in FIG. 3, the rubber block 20 has a center angle of 65 mm about the axis of the compression coil spring 5.
° A portion of a rubber cylinder having an inner and outer circumference of an arc of not more than 0 °, and at least at the time of the minimum load, the element wire 5a of the lower end winding portion and the element adjacent thereto along the circumferential direction of the compression coil spring 5. It is formed so as to abut the line 5b.

As shown in FIG. 2, the compression coil spring 5 in which the rubber block 20 is interposed between the wires 5a and 5b is provided between the upper seat 3 and the lower seat 4. Interposed. That is, the compression coil spring 5 is supported between the lower seat 4 and the upper seat 3 such that the bending direction of the coil axis is in the outer direction of the vehicle body. For example, when the strut 2 is offset as shown in FIG. 1, the compression coil spring 5 is held so as to coincide with the offset direction (right side in FIG. 2) of the strut 2 with respect to the strut 2. As a result, the compression coil spring 5
Is held with a larger compressive force on the right side of FIG. 2 than on the left side.

As shown in FIG. 2, the strut mount 10 includes a lower bracket 12 for supporting the upper seat 3 to the vehicle body 1 via a bearing 11, and an upper bracket 13 for bolting the lower bracket 12 to the vehicle body 1 together with the lower bracket 12. The vibration isolating rubber 14 is accommodated between them. On the other hand, a support bracket 15 is fixed to the tip of the rod 2 b of the strut 2, and the support bracket 15 is sandwiched between the lower bracket 12 and the upper bracket 13 by the vibration-proof rubber 14. That is, the strut mount 10 of the present embodiment
Is a load path separated type, and the strut 2 is supported by the vehicle body 1 through the vibration isolating rubber 14 so that vibration from the wheels 8 is absorbed, and the compression coil spring 5 is connected to the vehicle body 1 through the bearing 11. Because of the support, the stress generated during the compression and expansion operations is properly absorbed.

Here, for example, as shown in FIG. 7, simply bending the compression coil spring in the initial direction only causes the spring reaction axis RA to move in parallel, and the applied point of the spring reaction force is shifted from the coil axis CA. (The amount of deviation is indicated by e in FIG. 7), and uneven wear may occur in the bearing 11 (FIG. 2). On the other hand, in the present embodiment, as shown in FIG. 2, the point of application of the spring reaction force is located substantially at the center of the upper bearing surface US and substantially located on the coil axis CA.

Thus, in the suspension having the above structure, as shown in FIG. 1, the load input shaft AA does not coincide with the spring reaction force axis RA, and the strut shaft SA of the strut 2 and the load input shaft AA Makes an angle θ1, while the strut axis SA and the spring reaction force axis RA make an angle θ2.
LA denotes the axis of the lower arm 7 and KA denotes the kingpin axis. Due to the mismatch between the load input shaft AA and the strut shaft SA, a sliding resistance may occur between the cylinder 2a and the rod 2b of the strut 2. This sliding resistance is generated by the urging force of the compression coil spring 5. As a result, a smooth sliding operation of the rod 2b is ensured.

FIGS. 4 to 6 show an FEM analysis using an analysis model (not shown) corresponding to the compression coil spring 5 having the coordinates shown at the lower left of FIG. It shows the result of performing. This analysis model is modeled by several scalar springs interposed between 0.75 turns and 1.75 turns from the lower seating surface of the coil spring.
Is set so as to be 45 N / mm, and the spring characteristics are set so that the rubber block 20 contacts the strands 5a and 5b at the time of the minimum load.

First, FIG. 4 shows the change in the lateral force according to the central angle θc of the rubber block 20 as an arc. As the central angle θc increases, the lateral force Fs (N) of the compression coil spring 5 decreases. You can see that. FIG. 5 shows the relationship between the central angle θc and the lateral force reduction rate (%). When θc = 70 °, the lateral force decreases by about 5% as compared with the case where θc = 0 °. Note that θc = 0 ° is a minimum value in the simulation and does not actually exist. Therefore, it is necessary to set the minimum value to be practically manufacturable. However, in the present embodiment, the minimum value is required as described later. I do not.

FIG. 6 shows a compression coil spring having an initial torsion which is formed such that a coil axis passing through the center of the upper seat surface is curved at a predetermined curvature in a free state, like the above-mentioned compression coil spring 5. The rubber block 2 described above
It is an experimental result when experimenting the effect of 0 on the spring reaction force. More specifically, a rubber block having a range of various central angles θc for specifying a range in which the wire 5a of the lower end winding portion and the wire 5b adjacent to the wire 5a are in contact with each other is formed. It is the figure which projected the spring reaction-force axis when interposed between lines 5a and 5b on the xz plane. The spring reaction force axis is a line connecting the contact points of the spring reaction force acting on the upper seat surface and the lower seat surface.

In FIG. 6, the lowest x
The thick dashed line having the axial inclination represents the analysis result in the case where there is no rubber block.
A solid line having an axial inclination represents a case where the central angle θc is 0 °. As is clear from FIG. 6, the inclination of the spring reaction force axis in the x-axis direction decreases as the central angle θc increases from 0 ° (the contact portion with the element wire increases).

The following matters become clear from the above analysis results. That is, (1) the smaller the range of the central angle θc of the rubber block 20, the greater the effect of increasing the lateral force of the compression coil spring. (2) If the range of the center angle θc of the rubber block 20 is too large, not only the lateral force increasing effect is reduced, but also the adjacent strands 5a and 5b are evenly contacted on the work accuracy. Becomes difficult. (3) Conversely, if the range of the central angle θc of the rubber block 20 is too small, the production,
It becomes difficult to assemble, and it becomes difficult to design a shape that can abut the strands 5a and 5b in a stable state.

As a result, the center angle θc of the rubber block 20 is obtained.
Is desirably 65 ° or less. However, if the range of the central angle θc is too small, the above problem occurs. Therefore, the lower limit of the central angle θc is set to, for example, the element wire 5a and the element wire 5 of the rubber block 20 shown in FIG. It is desirable to set the width w of the portion in contact with 5b to be 20 mm or more. Although the maximum principal stress distribution (not shown) was obtained from the above analysis results,
It was confirmed that the stress distribution and its maximum value hardly changed even when the center angle θc of the rubber block 20 was changed.

In this embodiment, as shown in FIG. 2, the amount of bending of the compression coil spring 5 and the center angle θc of the rubber block 20 are appropriately set, and the magnitude of the lateral force on the strut 2 is reduced. It is adjusted appropriately and adjusted so that the contact point of the spring reaction force is located substantially at the center of the upper seat surface US. Thereby, lateral force is applied to the strut 2 in a stable state without uneven wear on the bearing 11.
Although the detailed description of the vibration isolating rubber 14 is omitted in the present application, the vibration isolating rubber 14 is designed such that the spring reaction force axis of the compression coil spring 5 passes through substantially the center of the upper seat surface US.

Although not shown, a rubber block may be interposed between adjacent wires near the upper seat 3 of the compression coil spring 5 instead of or together with the rubber block 20. Is also good. In this case, the rubber block interposed in the vicinity of the upper seat 3 of the compression coil spring 5 is disposed inside the vehicle body.

[0030]

The present invention has the following effects because it is configured as described above. That is, the strut type suspension device according to claim 1 forms the compression coil spring so that the coil axis passing through the center of the upper seat surface of the compression coil spring is curved at a predetermined curvature in a free state, and the compression coil spring is An elastic member is interposed between wires adjacent to the lower seat near the lower seat and / or an elastic member is interposed between wires adjacent to the upper seat near the upper side of the compression coil spring. In addition, since the compression coil spring is held so that the bending direction of the coil shaft is on the outside of the vehicle body, a desired lateral force can be appropriately applied to the strut, and a smooth cushioning operation can be secured. . Also, since there is no need to take any special measures when mounting the compression coil spring, the assembly is easy.

In particular, in the strut type suspension device according to the second aspect, the compression coil spring is formed such that the coil axis passing through the center of the upper seat surface of the compression coil spring is curved at a predetermined curvature in a free state. An elastic member is interposed between a wire of a lower end turn located outside the vehicle body of the compression coil spring and a wire adjacent to the turn of the lower end turn, and the coil shaft is bent. Since the compression coil spring is held so that the direction is toward the outside of the vehicle body, a desired lateral force can be appropriately applied to the strut with a simple configuration, and a smooth cushioning operation can be secured.

The elastic member may have a central angle of 65 ° about the axis of the compression coil spring.
In the following range, if it is constituted by the strand of the lower end winding portion and the rubber block disposed so as to abut on the strand adjacent thereto, the desired lateral force can be appropriately applied to the strut easily and inexpensively. Can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a strut type suspension device according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing an upper seat, a lower seat, and a strut mount in one embodiment of the present invention.

FIG. 3 is a perspective view of a rubber block provided to the strut type suspension device according to one embodiment of the present invention.

FIG. 4 is a graph showing a relationship between a central angle and a lateral force of a rubber block provided in a strut type suspension device according to an embodiment of the present invention.

FIG. 5 is a graph showing a relationship between a center angle of a rubber block provided to a strut type suspension device according to an embodiment of the present invention and a lateral force reduction rate.

FIG. 6 is a graph showing a state in which a spring reaction force axis when rubber blocks having various ranges of central angles are interposed is projected on an xz plane in one embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a supported state of an example of a compression coil spring to be compared according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body, 2 strut 3 Upper seat, 4 Lower seat 5 Compression coil spring 6 Knuckle, 7 Lower arm, 8 Wheels 10 Strut mount, 20 Rubber block US Upper seat, LS Lower seat

Claims (3)

[Claims] 1. A compression coil spring that supports an upper end of a strut on a vehicle body and is disposed between a lower seat fixed to the strut and an upper seat supported on the vehicle body so as to surround the strut, In a strut-type suspension device that supports wheels on the vehicle body through the struts,
The compression coil spring is formed so that a coil axis passing through the center of the upper bearing surface of the compression coil spring is curved at a predetermined curvature in the free state of the compression coil spring, and the compression coil spring is provided on the outside of the vehicle body of the compression coil spring. An elastic member is interposed between adjacent wires located near the lower seat and / or
Or, an elastic member is interposed between adjacent wires near the upper seat and located near the upper seat of the compression coil spring, and the compression coil spring disposed between the lower seat and the upper seat, A strut-type suspension device, wherein the coil shaft is held so that a bending direction of the coil shaft is directed to the outside of the vehicle body. 2. A compression coil spring is arranged between a lower seat fixed to the strut and an upper seat supported by the vehicle body, the compression coil spring surrounding the strut. In a strut-type suspension device that supports wheels on the vehicle body through the struts,
The compression coil spring is formed so that a coil axis passing through the center of the upper bearing surface of the compression coil spring is curved at a predetermined curvature in the free state of the compression coil spring, and the compression coil spring is provided on the outside of the vehicle body of the compression coil spring. An elastic member is interposed between the element wire of the lower end turn portion and the element wire adjacent to the element wire of the lower end turn portion, and is disposed between the lower seat and the upper seat. A strut-type suspension device, wherein the compression coil spring is held so that a bending direction of the coil shaft is directed to the outside of the vehicle body. 3. The element wire of the lower end turn and the element of the lower end turn in a range of a center angle of 65 ° or less about the axis of the compression coil spring. 3. The strut-type suspension device according to claim 2, comprising a rubber block disposed so as to abut on a wire adjacent to the wire.