JPS6036966B2 - Vehicle suspension system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle suspension system, and more particularly to a vehicle suspension system having a leaf spring device that can control the frictional force acting on the spring plates depending on the running condition of the vehicle.

2. Description of the Related Art Suspension systems used in vehicles such as automobiles generally include a stacked leaf spring device, whose longitudinally intermediate portion is connected to the axle, and both ends are connected to the vehicle body.

As is well known, the spring constant and the friction between the plates affect ride comfort, steering stability, and the like, and the degree of this also varies depending on the speed of the vehicle, the condition of the road, etc. In general, the ride comfort when driving on a good road is better when there is less friction between slopes, but the steering stability shows a tendency that is contrary to this.
On the other hand, in order to reduce the weight of vehicles and improve riding comfort, taper spring plates, which have a tapered part that decreases in thickness toward the edge of the plate, have come into use. Compared to the case where spring plates with a constant thickness are used, the number of spring plates required is smaller, and the friction between the plates is less, so it is necessary to increase the capacity of the shock absorber in order to improve riding comfort when driving on rough roads.

However, a large-capacity shock absorber is expensive, and even when damping is unnecessary, it always provides a fixed amount of damping, which may impair the comfort of the vehicle. In addition, if a clamping mechanism is provided in which the spring plates are brought into contact with each other in the thickness direction in order to increase the friction between the plates, the friction between the plates is almost constant in the conventional bolt-tightening clamp mechanism, so it is difficult to ride when driving on rough roads. Although the comfort can be improved, on the other hand, there is a drawback that the ride comfort becomes worse when driving on a good road. The present invention has been made under the above circumstances, and its object is to provide a suspension system for a vehicle that can always maintain optimum ride comfort and handling stability, regardless of the traveling speed or the condition of the traveling road. Our goal is to provide the following. Hereinafter, the present invention will be described with reference to an illustrated embodiment.

In FIG. 1, a stacked leaf spring device 1 constituting a suspension system includes a plurality of spring plates 2 (in the figure, there are three spring plates) overlapped in the thickness direction. In the illustrated example, the spring plate 2...
・Since all of the spring plates are tapered spring plates, all or part of these may not have a tapered portion. The spring plates 2 are tightened in the thickness direction by appropriate means 3 at their longitudinally intermediate portions, as in the case of the retainer, and are connected to the axle (not shown) of the vehicle. Clamp mechanisms 4, 4 capable of attaching the spring plates 2 in the thickness direction are provided on the side of the vehicle body a of the vehicle. In the illustrated example, the clamp mechanisms 4, 4 are provided on support members 5, 5 to which both ends of the stacked leaf spring device 1 are connected. That is, one support member 5 is provided with a pin 6 that rotatably supports the centerpiece formed at one end of the first spring plate 2, and the other support member 5 is provided with a pin 6 that rotatably supports the eyelet formed at one end of the first spring plate 2. A spring receiving member 7 is provided, with which the end portion of the pond 2 slides into contact from below. In addition, the support sections 5, 5 are provided with a pin 6, a pressing member 8 which can be raised and lowered and which faces the spring bearing member 7 at intervals, respectively.
8 is provided. Interposed between these pressing members 8, 8 and the third spring plate 2 are inserts 9, 9 made of a suitable material such as rubber. The support members 5, 5 are provided with fluid pressure cylinder devices 10, 10.

This cylinder device 10 includes a cylinder 11 attached to a support member 5 as illustrated in FIG.
1, a spring member 13 such as a disc spring installed in the cylinder 11 so as to be able to bias the piston 12 in the direction toward the head, and a piston rod 14 connected to the piston 12. There is. The above-mentioned self-pressing members 8, 8 are attached to the piston rod 14 at the tip thereof which protrudes upwardly through the through hole 15 of the support member 5. In addition, a boat 16 provided at the end of the head of each cylinder 9, 9, and the cylinder device 10, 1,
16, and is configured such that the clamp mechanisms 4, 4 can be driven by pressure fluid introduced from these boats 16, 16. The pressure cylinder device 10, 1 river,
Piping 17 and control valve 1 connected to boats 16, 16
8 to a pressure fluid source 19. On the other hand, the first and second integrating circuits 21, which are connected in series between the two control devices,
22 and the first control circuit 23, second and third control circuits 24, 25, fourth and fifth control circuits 26, 27 connected to each input terminal of the integrating circuits 21, 22, and each of these control circuits 23-27. The output terminal of the combining section 28 is connected to the control valve 18 via an amplifier 29.

Further, at the input end of the first integrating circuit 21, there is a fourth acceleration detector 30 for detecting the acceleration of vertical vibration of the vehicle body a.
A vehicle steering wheel operation angle detector 31 and a vehicle distance detector 32 are connected to an input end of the control circuit 26, and a manual operation section 33 is connected to an input end of the fifth control circuit 27. In the device configured as described above, for example, the output signals of the first to fourth control circuits 23 to 26 are cut off, and the operation section 33 is appropriately set to turn off the amplifier 29.
By keeping the output constant, the fluid pressure applied to the cylinder device 1 via the control valve 18 is maintained constant, and the stacked leaf spring device 1 operates in the same manner as in the conventional device.

In this case, the relationship between the vibration amplitude A of the plate end and the dynamic spring constant Kd in the stacked plate spring device 1 is, as shown in FIG. In some cases, it becomes like a mouth. Furthermore, as shown in Figure 4, the relationship between the amplitude A and the equivalent damping coefficient D based on interplate friction, etc. is as follows when the fluid pressure is a high constant value, and as shown in 2 when the fluid pressure is a low constant value. Become. Moreover, the first to third control circuits 23 to
If the control valve 18 is controlled by the output signal of 25, and the fluid pressure P is increased in accordance with the amplitude A, as shown schematically by dot chain E and H in FIGS. When the amplitude A is greater than 4, such as when driving, the fluid pressure is low and the dynamic spring constant is set small, resulting in good vibration isolation, and when the amplitude A is large, such as when driving on a rough road. In this case, the fluid pressure is high and the equivalent damping coefficient D is set high, resulting in good damping performance.

Therefore, a good ride comfort can always be obtained regardless of the condition of the road. Furthermore, when turning, a fourth
A control signal corresponding to the centripetal acceleration of the vehicle body is output from the control circuit 26, and the dynamic spring constant Kd is set high by increasing the fluid pressure as the centripetal acceleration increases. Therefore, tilting of the vehicle body due to centripetal acceleration is suppressed, and the steering stability of the vehicle during turning can be significantly improved. If necessary, instead of or in addition to the above-mentioned steering wheel operation angle detector 31 and vehicle speed detector 32, the displacement, speed, acceleration, etc. of the spring plates 2 in each stacked leaf spring device 1 on both sides of the vehicle body are detected. A means may be provided. In addition, in the automatic control as described above, all or part of each of the control circuits 2 to 27 may be provided with an appropriate reference setting section to appropriately set the control mode, or the above-mentioned manual Operation part 3
3 may be used to perform desired control that adapts to the driver's preference, load situation, etc. It should be noted that the present invention is not limited to the above-mentioned embodiments; for example, one of the clamp mechanisms 4 may be omitted, or three or more clamp mechanisms 4 may be provided.

Further, as illustrated in FIG. 5, either one of the supporting members 5 may be provided rotatably relative to the side of the vehicle body a. If necessary, as illustrated in FIG.
In addition, the ends of the spring plates 2 may be held between the spring plate 42 and the spring receiver member 7, and thereby the dynamic spring constant and the equivalent damping coefficient can be controlled at the same time. can. Alternatively, as illustrated in FIG. 7, the clamp mechanism 4 and the cylinder device 10 may be provided in the longitudinally intermediate portion of the spring plate 2 . Further, the number of spring plates is not limited to a plurality, but may be a single number. Furthermore, the eighth
As illustrated in the figure, a fluid pressure cylinder device 43 that does not require the spring member 13 may be used, or a piston rod 44 of the cylinder device may be made to protrude downward and a pressing member 45 may be provided at its lower end. Good too.
In this case, the cylinder device 43, the pressing member 45, etc. may be provided at both ends of the spring plate 2 as shown in FIG. 9, or the piston of the cylinder device 43 may be provided as shown in FIG. The rod 44 and the pressing member 45 may be connected via a push cable 46, for example. Instead of further providing the first and second integrating circuits 21 and 22'
A means for detecting the speed and displacement of this vibration may be provided, or a means for detecting the speed or displacement may be provided instead of providing the acceleration detector 30, and the acceleration and displacement, or the acceleration may be detected from these output signals. and speed may be calculated. In addition, various modifications and applications are possible within the scope of the gist of the present invention. As described above, the present invention includes a leaf spring device interposed between the axle and the vehicle body, and a clamp mechanism for tightening the spring plate of the leaf spring device in the thickness direction. The present invention is characterized by comprising a control means that is provided along the body of the vehicle and is capable of controlling the clamping force of the spring plate of the clamp mechanism in accordance with the running state of the vehicle.

Therefore, it is possible to control the spring constant, equivalent damping coefficient, etc. of the leaf spring device according to the driving conditions of the vehicle, the conditions of the driving road, etc., and it is possible to always maintain optimal ride comfort and handling stability. .

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing one embodiment of the present invention, and Fig. 2 is a system diagram showing an embodiment of the present invention.
FIGS. 3 and 4 are diagrams for explaining the operating characteristics of the same example, and FIGS. 5 to 10 are explanatory diagrams showing modifications of main parts. . DESCRIPTION OF SYMBOLS 1... Leaf spring device, 2... Spring plate, 4... Clamp mechanism, 6... Pin, 7... Spring receiving member, 8...
Pressing member, 10, 43...Fluid pressure cylinder device, 13
... Spring member, 18... Control valve, 19... Pressure fluid source, 20... Control device, 30-32... Detector. Figure 2 Figure 3 Figure 4 Figure 1 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] 1. A device that has a leaf spring device interposed between the axle and the body of the vehicle, and a clamp mechanism that tightens the spring plate of the leaf spring device in the thickness direction, when the body of the vehicle is 1. A suspension system for a vehicle, characterized in that the suspension system is provided with a control means that can control the spring plate clamping force of the clamp mechanism according to the running condition of the vehicle.