JPH02225113A - Suspension for vehicle - Google Patents

Abstract

PURPOSE:To enlarge front and rear compliance by setting a damping force in the contraction of a front shock absorber larger than that of a rear shock absorber while devising positions in which the respective front and rear shock absorbers are disposed. CONSTITUTION:A double Wishbone type suspension is provided with an upper arm 22 and two lower arms 24, 26 for supporting a wheel carrier 20 and a radius rod 28 for regulating the forward and backward movements of the wheel carrier 20. Also, it is provided with front and rear shock absorbers 30, 32 disposed spaced from each other back and forth of a car body to sandwich the rotary axis O. Then, a damping force of the front shock absorber 30 in its contraction is set larger than that of the rear shock absorber 32. Also, the front shock absorber 30 is disposed approximately orthogonally to the radius rod 28 in a vertical plane orthogonal to the rotary axis O, and the rear shock absorber 32 is disposed approximately vertically.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vehicle suspension, and more particularly to a double wishbone type rear suspension in which a wheel carrier is supported by an upper arm, a lower arm, and a radius rod.

(Prior art) In the double wishbone suspension described above,
Bushes made of rubber or other elastic material are arranged at the connection portions of the upper arm, lower arm, and radius rod with the vehicle body. Therefore, when the wheel carrier receives force from the road surface, it tends to displace or rotate around the axis of rotation of the wheel within the range of deflection of the bushing. If this displacement can be actively utilized, the compliance in the front-rear direction can be increased without changing the characteristics of the bush.

By the way, one shock absorber is usually arranged in a double wishbone suspension. In this case, the location of the shock absorber is determined from the viewpoint of whether the upper and lower blades that are applied to the wheel carrier are easy to hold, and whether or not they will interfere with other parts, regardless of compliance in the longitudinal direction. It will be done.

There has also been a proposal to use two shock absorbers for each suspension, examples of which are shown in FIG. 5 (Japanese Patent Application Laid-Open No. 1983-312207) and FIG. 6 (Japanese Patent Application Laid-Open No. 63-306910). This proposal also does not consider increasing the longitudinal compliance by utilizing the fact that the wheel carrier can be displaced around the rotational axis.

The suspension shown in FIG. 5 is of a so-called trailing arm type, and is intended to prevent vibration of the trailing arm due to brake reaction force. The trailing arm 10 is rigidly connected to the wheel carrier 11, and is swingably connected to the vehicle body at its front end. A shock absorber 13 and a shock absorber 14 are installed at the front and rear parts of the wheel carrier 11 across the rotational axis of the wheel 12.
is attached.

The suspension shown in FIG. 6 is a double wishbone type suspension that increases the damping force in the sprung resonance region. An upper arm 15 and a lower arm 16 are swingably connected to a wheel carrier 17, a shock absorber 18 extends from the lower arm 16, and a shock absorber 19 located forward of the shock absorber 18 extends from the upper arm 15.

(Problem to be Solved by the Invention) In the suspension shown in Fig. 5, when the wheel rides on a protrusion on the road surface, the wheel swings around the front end of the trailing arm, but at this time, the longitudinal compliance is It does not change. If the spring constant in the longitudinal direction of the elastic bush disposed at the front end of the trailing arm is set to be soft, the longitudinal compliance can be changed. but.

If this is done, the alignment is likely to change due to forces from the road surface, impairing steering stability.

In the suspension shown in Figure 6, the lower arm has a particularly high rigidity, and the upper arm is bifurcated into a bifurcated shape, which also has a large support rigidity, so the wheels could easily run over protrusions. At this time, substantially no displacement of the wheel carrier about the axis of rotation of the wheel occurs.

An object of the present invention is to provide a vehicle suspension that can change longitudinal compliance without changing the spring constants of bushings provided in association with the upper arm, lower arm, and radius rod.

(Means for Solving the Problems) The present invention provides a wheel carrier on which a wheel is mounted, an upper arm and a lower arm arranged in the lateral direction of a vehicle body and supporting the wheel carrier, and regulating movement of the wheel carrier in the longitudinal direction. Equipped with a radius rod that
The suspension includes the upper arm, the lower arm, and the radius rod connected to the vehicle body via an elastic bushing so that the wheel carrier is displaced around the rotation axis of the wheel, and the suspension is connected to the vehicle body across the rotation axis. The shock absorber includes a front shock absorber and a rear shock absorber that are spaced apart from each other in the longitudinal direction, and the damping force of the front shock absorber when it is compressed is set to be larger than the damping force of the rear shock absorber when it is compressed. In a standard state, the front shock absorber is arranged to be substantially perpendicular to the radius rod in a vertical plane perpendicular to the axis of rotation when the front shock absorber and the radius rod are projected from the side; The shock absorber of is arranged so that it is almost vertical in its standard state.

The upper arm, lower arm and radius rod are arranged and/or shaped such that the wheel carrier is displaced about the axis of rotation of the wheel. The elastic bushings disposed at the connections between these members and the vehicle body may be the same as those conventionally used.

The standard state may be a state in which a vehicle loaded with a standard load is neither bouncing nor rebounding.

(Operation and Effect) When a wheel of a running vehicle rides on a protrusion and the wheel carrier receives an upward force, the front shock absorber and the rear shock absorber tend to contract. At this time, since the damping force when the front shock absorber contracts is greater than the mechanical damping force when the rear shock absorber contracts, the rear shock absorber contracts with a larger stroke, and eventually the wheel carrier Rotate around the axis in the direction of wheel rotation. by this,
Front and rear compliance increases.

Increasing the longitudinal compliance when riding on a protrusion or the like is equivalent to reducing the spring constant of the bushings provided in relation to the upper arm, lower arm, radius rod, etc.

Therefore, the impact can be reduced and the riding comfort can be improved.

When the wheel carrier is displaced around the axis of rotation, substantially no bending moments act on the front and rear shock absorbers. As a result, the friction when the shock absorber expands and contracts can be reduced, and the durability of the shock absorber can be improved.

Bushes provided in connection with the upper arm, lower arm, and radius rod can have exactly the same characteristics as conventional ones, so changes in alignment can be maintained in the same state as conventional ones. In other words, ride comfort is not secured at the expense of handling stability, but it is possible to achieve both.

(Example) The double wishbone suspension shown in FIGS. 1 and 2 includes a wheel carrier 20, an upper arm 22, two lower arms 24, 26, a radius rod 28, and two shock absorbers 30, 32. including.

The wheels 33 are mounted on the wheel carrier 20 with a structure known per se.
can be attached to. Wheel carrier 20 has upper arm 22% lower arm 24.26 and radius rod 2
8, the wheel 33 is supported so as to be displaced or rotated around the rotational axis O of the wheel 33.

The upper arm 22 has an A- or V-shaped planar shape, and is connected to the wheel carrier 20 via a ball joint 34 at an end 23a that is outward in the lateral direction of the vehicle body. The two inner end portions 23b and 23c of the upper arm are swingably connected to the vehicle body via a rubber bush 36.

The lower arm 24 located below the upper arm 22 and in front of the wheel rotation @aO is made of a substantially straight bar member.

The lower arm 24 has a ball joint 3 at its outer end.
8 to the wheel carrier 20, and at its inner end to the vehicle body via a rubber bushing 40.

The lower arm 26 located below the upper arm 22 and behind the rotational axis 0 is made of a substantially straight member. The lower arm 26 is connected at its outer end to the wheel carrier 20 via a ball joint (not shown), and at its inner end to the vehicle body via a rubber bushing (not shown). .

The radius rod 28 is connected to the wheel carrier 20 at its rear end. The radius rod 28 extends forward or diagonally forward of the vehicle, and is swingably connected to the vehicle body via a rubber bushing 42 at its front end. The radius rod 28 restricts the movement of the wheel carrier 20 in the longitudinal direction.

The two shock absorbers 30 and 32 are arranged in the front-rear direction of the vehicle across the rotational axis 0, with the shock absorber 30 located at the front and the shock absorber 32 located at the rear. The shock absorber 30 is connected to the wheel carrier 20 via a ball joint 44 at its lower end.
Further, the shock absorber 32 is connected to the wheel carrier 20 via a ball joint 46 at its lower end. The shock absorber 30 can also be connected to the lower arm 24 and the shock absorber 32 can be connected to the lower arm 26. The upper ends of both shock absorbers are swingably connected to the vehicle body. This connection structure may be of any type known per se. A coil spring 31 is disposed surrounding a rear shock absorber 32, and extends between the shock absorber 32 and the vehicle body. A coil spring can also be arranged around the front shock absorber 30.

The damping force of the front shock absorber 30 when it is compressed is set to be larger than the damping force of the rear shock absorber 32 when it is compressed. Do this like this:

For example, the damping force of the front shock absorber 30 during contraction can be set to be greater than the damping force of the rear shock absorber 32 in all piston speed ranges.

For this purpose, two shock absorbers with different characteristics may be used.

As another example, for example, if the piston speed is 0.5I
At speeds above I/s, the damping force of the front shock absorber 30 when compressed is greater than that of the rear shock absorber 32, but in a range lower than the piston speed, the damping force of both shock absorbers when compressed is the same. It can also be set as follows. One shock absorber is a normal one, and the other shock absorber is a normal one.

The two liquid chambers in the cylinder separated by the piston are communicated through a bypass passage provided in the piston rod, and a valve that opens when the piston speed reaches 0.5 m/s or more is placed in the bypass passage. can.

As another example, both shock absorbers have the same characteristics, and when assembled to the vehicle body, one is positioned obliquely and the other is positioned approximately vertically.

When the front shock absorber 30 is in the standard state, the shock absorber 30 and the radius rod 28 are located in a vertical plane orthogonal to the rotation axis IwO projected from the side, that is, in FIG. 1 and in FIG. are arranged almost perpendicular to. The rear shock absorber 32 is arranged substantially vertically in the standard state. Almost perpendicular or almost perpendicular means something other than completely orthogonal or vertical.
This means that there may be some deviation.

In the illustrated embodiment, the radius rod 2B is arranged diagonally so as to face upward toward the front of the vehicle, while the shock absorber 30 is arranged diagonally so that its lower end is located forward of its upper end. They are arranged in a nearly orthogonal relationship.

According to this arrangement, when the tire rides on the protrusion, the rear end of the radius rod 2B is connected to the wheel carrier 20.
Since it acts to push out the lower part of the wheel carrier 20 rearward, it becomes easier to displace the wheel carrier 20 rearward. Also,
It is easy to set the damping force when the shock absorber 30 is compressed to be larger than the damping force when the shock absorber 32 is compressed.

In order to accurately maintain the positional relationship between the two shock absorbers 30 and 32 and to ensure ease of assembly, the third
A bracket 50 shown in the figures and FIG. 4 is used.

The bracket 50 consists of a highly rigid substrate 51 and supports 52 and 53 welded to the substrate 51. Spring receiver 5
4.55 is welded to the substrate 51, and a rubber cushion 56 is attached.
．． 57 are provided on the supports 52 and 53, respectively.

Piston rod 30a of front shock absorber 30
extends through a through hole in substrate 50 to support 52 and is coupled to cushion 56 .

The coil spring 29 surrounding the shock absorber 30 is then hooked to the spring receiver 54. Further, the piston rod 32a of the rear shock absorber 32 extends to the support 53 through the through hole of the base plate 50, and is coupled to the cushion 57.

The coil spring 31 is latched onto a spring receiver 55.

When the coil spring 29 is not arranged around the shock absorber 30, the spring receiver 54 is omitted.

In the production line, two shock absorbers 30.
The upper ends of the shock absorbers 30 and 32 can be held in a so-called subassembly state with their upper ends coupled to the bracket 50, and by assembling this subassembly to the vehicle body 60, the two shock absorbers 30 and 32 can be coupled to the vehicle body. This can improve work efficiency. Also, support 52.5
3 into the holes 61 and 62 provided in the vehicle body 60, and
0 and the vehicle body 60 using bolts 63 and nuts 64, the number of bolts and nuts required can be smaller than the number of bolts and nuts required when each shock absorber is coupled to the vehicle body. This allows cost reduction.

As shown in FIG. 2, when a wheel 33 of a vehicle traveling forward runs onto a protrusion 70 on the road surface, a force F is applied from the protrusion. As a result, the wheel carrier 20 has a connection point P between the front shock absorber 30 and the wheel carrier 20, and the length 2 of a perpendicular drawn from the connection point P to the line of action of the force F and the force F. The rear shock absorber 32 has a larger stroke because a moment determined by the product of Shrink. As a result, the wheel carrier 20 rotates around the rotation axis 0, and since this rotation is the same as the direction in which the wheel is rotating, the rotation axis eventually moves to 01, and the connection point P becomes PI. Then, the grounding point J moves to J. In this way, the wheel carrier rotates and the longitudinal compliance is increased.

As shown in FIG. 1, when the front shock absorber 30 is arranged at an angle, a force F3 smaller than the vertical component F2 of the force F acts on the front shock absorber 30. On the other hand, a vertical force F2 acts on the rear shock absorber 32. Therefore, shock absorber 30.3
Even if the two characteristics are set to be the same, the damping force of the front shock absorber 30 when it is compressed is apparently larger than the damping force of the rear shock absorber 32 when it is compressed.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the side surface of the suspension, Fig. 2 is a schematic diagram showing the action, Fig. 3 is a perspective view of a bracket that connects two shock absorbers, Fig. 4 is a cross-sectional view of the bracket, and Fig. 5 6 shows a conventional suspension, with FIG. 5 being a side view and FIG. 6 being a perspective view. 20: Wheel carrier, 22 Near shoulder arm, 24.26: Lower arm, 28 Ni radius slot, 30.32: Shock absorber, 36.40.42: Push, 50 Ni bracket. Figure 1 24, 7b; 077'-2~ Agent Patent Attorney Nobuyuki Matsunaga Figure Figure

Claims (1)

[Claims] The wheel carrier is provided with a wheel carrier on which a wheel is attached, an upper arm and a lower arm that are disposed in the lateral direction of the vehicle body and support the wheel carrier, and a radius rod that restricts the movement of the wheel carrier in the longitudinal direction. A suspension in which the upper arm, the lower arm, and the radius rod are connected to the vehicle body via elastic bushings so as to be displaced around the rotation axis, and are spaced apart from each other in the longitudinal direction of the vehicle across the rotation axis. A front shock absorber and a rear shock absorber are arranged, and a damping force of the front shock absorber when compressed is set to be larger than a damping force of the rear shock absorber when it is compressed, and the front shock absorber is configured to , in a standard state, the front shock absorber and the radius rod are arranged to be substantially perpendicular to the radius rod in a vertical plane perpendicular to the axis of rotation projected from the side;
A vehicle suspension in which the rear shock absorber is arranged so as to be substantially vertical in a standard state.