JPS6148445B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a shock absorber applied to a suspension system of an automobile.

Background Art As is well known, this type of suspension system supports the weight of the vehicle body through the wheel axle, prevents wheel vibrations from being directly transmitted to the vehicle body, and reduces driving force, braking force, lateral reaction force during steering, etc. information from the wheels to the vehicle body,
This is to improve riding comfort and to prevent excessive loads from being applied to each part. Such suspension systems are equipped with shock absorbers that generate damping force through the action of springs, and this damping force absorbs vibrations of the car, suppresses the movement of the car, or absorbs shocks applied to the wheels. It temporarily absorbs force, softens the impact, and prevents it from being transmitted directly to the vehicle body.

By the way, in conventional shock absorbers of this type, if the spring pressure of the buffer spring is set to be strong and hard and the damping force is set high to suppress the movement of the vehicle, the ground contact of the vehicle will be improved and stable driving performance will be ensured. , bumps and vibrations due to irregularities and undulations on the road surface become more intense, resulting in poor ride quality and comfort.In order to obtain a comfortable ride, if the spring pressure is set to be soft and the damping force is set to a low value, the ground running performance deteriorates. Then, contradictory issues arose. Furthermore, if you weaken the spring pressure and set the damping force to a low value like this,
For example, when an impact force is applied to the front wheels due to unevenness of the road surface, the vehicle body may be pushed up and agitated, causing large vibrations or shaking vertically and horizontally.
Moreover, it takes time to attenuate and absorb such vibrations and large tremors, and recovery to a stable running state cannot be performed quickly, which results in the problem of not only taking time but also significantly impairing ride comfort.

Disclosure of the invention This invention has been made in view of the above points.
Under normal driving conditions, the spring pressure of the buffer spring is set to a low and soft setting to provide a comfortable ride. The purpose of this system is to temporarily increase the spring pressure of the springs to make them harder and to quickly dampen and absorb the vibrations and shaking of the car body caused by this impact force.

In order to achieve this object, the present invention provides a buffer member consisting of a normal spring and a shape memory alloy spring interposed between the vehicle body and the axle, and a sensor for detecting vibration or acceleration applied to the axle at or near the axle. In addition, a means is provided to heat the shape memory alloy spring to return to its shape when the sensor's detection output exceeds a preset output, and when an impact force is applied to the wheel due to an uneven road surface, etc. By making the spring pressure of the spring superfluous with the spring pressure of the shape memory alloy spring, the spring pressure of the buffer member is temporarily made stronger and harder, increasing its damping force, and the buffering effect of the buffer member is suppressed under normal running conditions. Usually, the configuration is such that it is performed only by the spring pressure of a spring.

According to this invention, in normal running conditions on flat ground, the buffering effect of the buffering member is normally performed only by the spring action of the spring, and the spring pressure acts softly, so the damping force is set low. You can enjoy a comfortable ride. In addition, when an impact force is applied to the wheel, that is, the axle that supports it due to unevenness of the road surface, etc., the shape memory alloy spring is restored to its shape, and the spring pressure is added to that of the normal spring, and the spring pressure is used as a shock absorber. The spring pressure from the members acts strongly and hard, and the damping force is temporarily set high, so the impact force is quickly absorbed and alleviated, and the impact force causes the vehicle body to vibrate and move vertically or horizontally. The large tremors are quickly attenuated and absorbed. Furthermore, since the shape memory alloy spring has excellent responsiveness, it is possible to quickly restore driving stability with good responsiveness even on a rough road with unevenness or undulations. Therefore, stable and good running performance can be obtained at all times regardless of road surface conditions or running conditions, and ride quality and comfort are also improved.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

Figures 1 and 2 show the main parts of a suspension system for a four-wheeled vehicle to which the present invention is applied. Suspension 1 between
5 and 15 are interposed, respectively, and the vehicle body 10 is suspended on both axles 11 and 13 by these suspensions 15 and 15, respectively. In addition, in the figure, only one side in the width direction of the vehicle body 10 is shown for simplicity.

As shown in FIG. 3, the suspension 15 includes a mounting member 16 pivotally connected to the axles 11 and 13;
A mounting member 17 fixed to the vehicle body 10, a coil spring 18 made of a normal spring material interposed between the mounting members 16 and 17, and a coil spring 18 made of a shape memory alloy arranged in parallel with the normal spring 18. 20 (hereinafter referred to as a memory alloy spring).

By heating the memory alloy spring 20 to a predetermined temperature, the shape returns to the initial state stored in advance and the spring pressure returns to the desired set pressure. It is formed to be approximately "0". Terminals 2 connected to the power supply circuit 33 at both ends of the memory alloy spring 20
1 and 22 are provided.

A wheel 12, that is, an axle 1 is mounted at a predetermined position on the front axle 11.
A sensor 23 is attached to detect the vibration or acceleration when an impact force is applied to the sensor 1 . Note that this sensor 23 may be attached to the mounting member 16, for example.
It may be installed on the

Next, FIG. 2 is a block diagram showing an example of a circuit configuration for embodying the present invention, in which 30 is a comparator and 31 is a setting device that outputs a set output according to a preset vibration value or acceleration value. Output to comparator 30.
Further, 32 is a drive circuit which receives a signal from the comparator 30 and drives the power supply circuit 33. Power circuit 3
3 is a power supply 34 and a switch 35 for turning it on and off.
It is connected between the terminals 21 and 22 of the memory alloy spring 20.

In the above configuration, when the car is running on a normal flat road, the detection output from the sensor 23 is at approximately "0" level, so the comparator 3
No signal is output from 0, and all memory alloy springs 20 are kept at room temperature. As a result, the vibration absorption and shock mitigation effects of the suspension 15 are usually performed only by the spring pressure of the spring 18, and the spring pressure acts softly. Therefore, the damping force against vibrations and shocks caused by the suspension 15 is adjusted to be slightly lower, thereby maintaining good riding comfort and comfort.

On the other hand, as shown in Fig. 4, the front wheel 12
When the vehicle gets stuck in the unevenness A generated on the road surface, the impact force generated at that time is applied to the front wheel 12. Then, the sensor 23 detects vibration or acceleration caused by this impact force and outputs a detection signal corresponding to this to the comparator 30. The comparator 30 compares and calculates the detection signal from the sensor 23 and the setting output from the setting device 31, and sends a signal to the drive circuit 32 when the detected value exceeds a preset setting value. The drive circuit 32 is driven by this signal, and the power supply circuit 33
Turn on the switch 35. As a result, all the memory alloy springs 20 provided in each suspension 15 are heated by the power supply 34, and
The shape instantly returns to its initial state, and at the same time, the spring pressure recovers to the desired set pressure. As a result, the spring pressure of each suspension 15 is increased to be equal to the sum of the spring pressure caused by the memory alloy spring 20 and the spring pressure caused by the normal spring 18. Therefore, the spring pressure temporarily acts harder and harder than when the vehicle is running on flat ground, and the damping force value against vibrations and shaking is set high. Therefore, the impact force applied to the front wheels 12 is quickly absorbed and buffered at that point, and at the same time, the vibrations and shaking of the vehicle body caused by this impact force are quickly damped and absorbed with good response. In this case, since the memory alloy spring 20 has extremely good responsiveness and returns to its shape instantly, phenomena such as shock absorption, vibration of the vehicle body, and large shaking are attenuated and absorbed in a very short period of time and are eliminated. Therefore, unlike in the past, if the vibrations or large tremors continue for a long time after passing the unevenness A, the vibrations and shaking will not continue, and the stable running state can be quickly recovered in a short time. Thereafter, when the vehicle returns to a stable running state, the power to the memory alloy spring 20 is cut off, the vehicle body 10 is suspended and supported only by the spring pressure of the normal spring 18, and its damping force value is adjusted to a lower value again. Ru.

In the embodiment, all the memory alloy springs are made to return to their shape when the front wheel 12 fits into the unevenness A, but only some of them, for example, the memory alloy spring on the rear wheel side, are electrically heated. The shape may be restored. Furthermore, it is also possible to provide a plurality of levels of strength to the reference value set by the setting device 31, so that the strength of the spring can be sequentially switched in stages. In this way, it is possible to switch and adjust the damping force value by the spring in a plurality of high and low levels corresponding to the impact level according to the unevenness of the road surface.

Furthermore, if a manual switch 40 for changing the strength of the spring is provided in the circuit shown in Fig. 2, and this is placed on the instrument panel, the driver can adjust his/her own control at any time depending on the unevenness of the road surface or the driving condition. You can select and adjust the damping force value to suit your preference.

Next, FIG. 5 shows another example of the spring constituting the suspension, in which the mounting members 16, 1
Memory alloy springs 42 are fitted inside the normal spring 41 interposed between the springs 7 and 7 in parallel with each other with their central axes coaxial. A power supply circuit 33 is connected to both ends of the memory alloy spring 42.
Terminals 43 and 44 are provided to be connected to.

FIGS. 6 and 7 show still other examples of springs constituting the suspension, and this spring 50
consists of a pipe-shaped member 51 formed in a spiral shape from plastic or the like, a normal spring 52, and a memory alloy spring 53. The springs 52 and 53 are stacked on top of each other and assembled into one body, and are fitted into the member 51 from one side to form an integral unit.
Terminals 54 and 55 connected to the power supply circuit 33 are provided at both ends of the memory alloy spring 53.

According to these examples, the configuration can be made more compact than the springs shown in the above embodiments.

FIG. 8 shows another example of this suspension, in which a pair of normal springs 60, 60 are interposed at a predetermined interval on both sides between the mounting members 16, 17, and a memory alloy spring is installed approximately in the center between them. 61 are arranged. In this case, the normal spring 60 may be provided in the center, and a pair of memory alloy springs may be arranged on both sides thereof.

In the example, the suspension on the rear wheel side is composed of a leaf spring consisting of a plurality of leaf springs, and one to two leaf spring-like memory alloy springs are arranged between them.
A plurality of sheets may be installed alternately.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the main parts of a suspension system in a four-wheeled vehicle to which the present invention is applied, FIG. 2 is a block diagram showing an example of a circuit configuration for embodying the present invention, and FIG. FIG. 4 is a side view of a main part of a suspension to which the invention is applied; FIG. 4 is a side view of a main part illustrating the operation of the shock absorber according to the invention; FIG. figure,
FIG. 7 is a perspective view showing another example of a spring constituting the suspension, and FIG. 8 is a side view of a main part showing still another example of the suspension. 10... Vehicle body, 11, 13... Axle, 18, 4
1, 52, 60... Normal spring, buffer means, 20,
42, 53, 61...memory alloy spring, buffer means,
23... (vibration or acceleration) sensor, 31... setting device, 30... comparator, 32... drive circuit, 33
...Power circuit.

Claims (1)

[Claims] 1. A buffer means consisting of a normal spring and a shape memory alloy spring interposed between the vehicle body and the axle, a vibration or acceleration sensor disposed at or near a predetermined position of the axle, and a detection output of this sensor. a comparator that compares and calculates a set output set by a setting device and outputs a signal when the detected output exceeds the set output; and a comparator that heats the shape memory alloy spring based on the signal from the comparator. A shock absorber for a vehicle suspension system comprising means for restoring the shape of the shock absorber.