JPH0586503B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a frequency-sensitive shock absorber useful for use in a suspension system in a vehicle such as an automobile, and more specifically, to a frequency-sensitive shock absorber useful for use in a suspension system of a vehicle such as an automobile. The present invention relates to a frequency-sensitive shock absorber that automatically and appropriately controls the damping force generated by a damper mechanism.

[Conventional technology]

Generally, as shown in FIG. 7, a suspension system for an automobile, etc., has a sprung vehicle body 1 and a suspension spring 3 disposed in parallel between an unsprung mechanism 2 supported by tires 5 having a spring action. It can be expressed as a two-degree-of-freedom system that is elastically supported via the damper mechanism 4.

Therefore, in this case, if we exclude the damper mechanism 4 and focus only on the suspension spring 3,
The vibration frequency characteristic of the sprung vehicle body 1 is as shown in Fig. 8, when the vertical axis represents the sprung acceleration speed G and the horizontal axis represents the road surface input frequency, the sprung mass resonance frequency ₁ (usually 1 to 2 Hz) Two resonance regions (spring resonance point and unsprung resonance point) are generated at the unsprung resonance frequency ₂ (usually around 10Hz) and the acceleration becomes large.

In this way, as a vibration system, a sprung resonance region and an unsprung resonance region inevitably occur, and the large vibration acceleration in these resonance frequency ₁ and ₂ regions impairs the ride comfort of the vehicle.

Therefore, in order to suppress the large vibration acceleration in such a resonance region, if the damping force generated by the damper mechanism 4 is increased to measure the damping effect, in other vibration regions where vibration acceleration is small, the unsprung vibration will be highly damped. This is not preferable because the force is directly transmitted through the damper mechanism 4 to the sprung vehicle body 1 side, making the spring characteristics feel stiff and causing discomfort to the occupants.

For the above reasons, the applicant first designed the damper mechanism 4 in such a suspension system for a vehicle to have a structure in which the damping force can be adjusted, and to bias the damper mechanism 4 in response to the magnitude of the vibration acceleration that the damper mechanism 4 itself receives. proposed a device that automatically adjusts the damping force by the movement of an actuating member (see Utility Model Application Publication No. 100103/1983).

According to this device, when the vibration between the sprung mass and the unsprung mass enters the resonance range, the damping force generated by the damper mechanism 4 automatically increases to produce a large damping effect, and in other driving conditions where vibration acceleration is low. In this case, the damping force generated by the damper mechanism 4 can be kept low and a good vibration damping effect can be exhibited.

[Problem that the invention seeks to solve]

As mentioned above, in this type of suspension system, a control system that automatically increases the damping force generated by the damper mechanism in the sprung and unsprung resonance regions is effective, as is the case with the previously proposed device. Vibration is effective.

Therefore, a first object of the present invention is to make the damping force generated by the shock absorber in this type of suspension system variable in accordance with the magnitude of the vibration acceleration between the sprung mass and the sprung mass.

Furthermore, in the case of the above-mentioned device proposed earlier,
Since a self-switching damper mechanism is used, it is necessary to incorporate structural members such as an actuating member that responds to vibration acceleration or a variable orifice that works in conjunction with the damper mechanism itself.
In this case, the structural shape of the entire mechanism must be changed.

In contrast, it is an object of the present invention to provide a shock absorber with adjustable damping force that can be relatively easily adopted by improving the conventional type or by adding an additional mechanism.

Furthermore, in such a vibration system, it may not be sufficient to control the damping force generated by the damper mechanism based only on the frequency of input vibration from the road surface. This is because if the damping force generated by the damper mechanism is controlled only by the frequency of the road surface input vibration, for example, the generated damping force of the damper mechanism will be affected even when the vehicle is maneuvered at high speed while driving outside the resonance area. This is because it is inconvenient that it is not possible to suppress the rolling of the vehicle body by increasing the force.

Therefore, the present invention provides a device that can control the damping force generated by a damper by selectively or preferentially applying input elements such as vehicle speed and steering angle in combination with the input vibration frequency. The purpose is also to

[Means for solving problems]

Therefore, in the present invention, there is provided a resonance detection mechanism that detects the occurrence of resonance of spring vibration, a signal processing mechanism that holds the continuation state of resonance detected by the resonance detection mechanism, and a signal processing mechanism that receives a hold signal from this signal processing mechanism and The damping force of the damper mechanism is controlled by a drive mechanism that controls the damping force adjustment actuator of the damper mechanism.

In addition to the above, a vehicle speed signal or a steering angle signal is input to the drive mechanism along with a hold signal of the drive mechanism, and these input signals are applied selectively or preferentially to perform damping force control. be.

[Effect]

That is, the resonance detection mechanism resonates with the resonance frequency of the spring vibration and acts to detect the resonance frequency range. Therefore, by setting the resonance conditions of the plurality of resonance detection mechanisms to the sprung resonance frequency and the unsprung resonance frequency, each resonance region can be detected.

Then, these detection results are continuously held by the signal processing mechanism only when they occur continuously, and act as control signals for the drive mechanism that controls the damping force adjustment actuator.

As a result, the damper mechanism increases the generated damping force only in the resonance region based on the control signal from the drive mechanism, and exhibits an effective damping effect.

Moreover, since the damping force control described above is a vibration frequency sensitive method using a resonance detection mechanism, it can be easily applied to existing vehicles such as automobiles that are equipped with damper mechanisms capable of adjusting the damping force.

In addition, the vehicle speed and steering angle signals input to the drive mechanism are applied selectively or preferentially in combination with input signals from the signal processing mechanism, and act to control rolling, etc. that occurs in the vehicle body. .

〔Example〕

FIG. 1 is a configuration diagram showing an embodiment of the frequency-sensitive shock absorber according to the present invention, which is a resonance detection mechanism for detecting the occurrence of resonance in a sprung vehicle body 1 in a suspension system of an automobile or the like. A resonance detection sensor 7 (basically a set of two together with a resonance detection sensor for the unsprung mass 2) is integrally installed, and the detection signal of the resonance detection sensor 7 is sent to a hold circuit 8 which is a signal processing mechanism. After processing, the controller 9, which is a drive mechanism, selects the processed signal and amplifies the power based on this processed signal, thereby adjusting the damping force generated by the damper mechanism 4.

Resonance detection sensor 7 which is the above resonance detection mechanism
As shown in FIG. 2, an adjuster member 12 for adjusting a spring load is screwed into one open end of a cylindrical housing 11 made of a non-magnetic material to close the end. This adjuster star member 12 is a hollow body with a closed end, and has a small hole 13 in the closed surface of the screwed end. The supported plug 16 is movably provided under sliding tightness by an O-ring 17.

Further, a cap 23 is screwed onto the other open end of the casing 11, and a spring 20 made of a non-magnetic material is provided in the center of the casing 11, one end of which is in contact with the tip of the adjuster member 12. The spring 2 also has one end in contact with the cap 23.
An inertial member 22 made of a permanent magnet sandwiched between springs 21 identical to those of 0 is movably arranged, and a hollow portion including the volume compensation chamber 14 is filled with oil. In addition, 22a indicates an orifice provided in the inertial member 22, and 18 and 24 indicate O-rings for sealing.

The housing 11 also includes an inertial member 22, as shown in FIG. 3, which is a sectional view taken along line A-A in FIG.
A reed switch 19 is disposed in a small hole 25 that is located in the other side of the movement range of the springs 2 and 2, and the reed switch 19 is disposed in a small hole 25 that is drilled horizontally.
They are provided at symmetrical positions A, A' and B, B' on both upper and lower sides with respect to the stable position of the inertial member 22 supported by 0 and 21, respectively.

As mentioned above, the reason why the reed switch 19 is provided in two sets, one at the A, A' position and the other at the B, B' position outside of it, is because the reed switch 19 is provided in two sets, one at the A, A' position and the other at the B, B' position outward from the reed switch 19. This is detected by the reed switches 19 at the A and A' positions, and the large amplitude input time with larger resonance energy is detected separately by the reed switches 19 at the B and B' positions. This is to adjust the damping force generated by the damper mechanism 4, which will be described later, in two stages according to the time and large amplitude.

On the other hand, the hold circuit 8, which is a signal processing mechanism,
As shown in FIG.
The circuit signals A and B associated with the closing of each reed switch 19 are input to the NAND circuit 28 through filter circuits configured to constitute discharge circuits 6 and 27, respectively, and the output C from this NAND circuit 28 is retriggered. The hold signal E is processed by a blue mono multivibrator 29 and a flip-flop circuit 30 to generate a hold signal E.

Note that the hold circuit 8 is arranged in two pairs of reed switches 19 in the resonance detection sensor 7 (one pair and two pairs in the A, A' position and in the B, B' position). In addition to the set corresponding to the position B, there is another two set corresponding to the set B and B', and furthermore, the resonance of the two set corresponding to the sprung mass resonance frequency ₁ and the sprung mass resonance frequency ₂ . Including the detection sensor 7, the hold circuit 8 has a total of four sets.

As described above, the hold signal E is transmitted from the set of hold circuits 8 corresponding to the reed switches 19 at positions A and A'.
A hold signal F is transmitted from the set of hold circuits 8 corresponding to the reed switches 19 in the B and B' positions. In addition, the resonance detection sensor 7 that detects the sprung mass resonance frequency ₁ and the resonance detection sensor 7 that detects the sprung mass resonance frequency ₂ each have a resonance frequency
₁ and ₂ , the spring constants of the springs 20 and 21 and the mass of the inertial member 22 are selected.

Furthermore, as shown in FIG. 6, the controller 9, which is a drive mechanism, inputs hold signals E and F from each hold circuit 8, and inputs a damping force selection circuit 31.
After processing the selected resultant signal by a power amplifier circuit consisting of power transistors 32, 33 and their driver circuits 34, 35, damper mechanism 4 is selected based on each signal.
The damping force adjustment drive solenoids 36 and 37 are actuated.

The selection of the hold signals E and F by the damping force selection circuit 31 involves, for example, operating the drive solenoid 36 to reduce the damping force generated by the damper mechanism 4 slightly for the hold signal E when the resonance energy is small and the amplitude is small. When the hold signal F at a large amplitude indicating that the resonance energy is large is transmitted, the drive solenoid 37 of the damper mechanism 4
act to further increase the generated damping force.

According to the frequency-sensitive shock absorber of the present invention constructed as described above, each resonance detection sensor 7 vibrates together with vehicle vibration (road surface input frequency) while the vehicle is running. At this time, the inertial member 22
and the spring 20 that supports it from both sides,
The natural frequency of the inertial member 22 of the resonance detection sensor 7, which is determined by the spring constant of 21, is set to a sprung resonance frequency ₁ and an unsprung resonance frequency ₂ according to their respective roles (spring and unsprung). By setting this, when sprung resonance and unsprung resonance occur, the inertia member 22 of the corresponding resonance detection sensor 7 vibrates greatly, which acts on the reed switch 19 placed in the relevant movement range, thereby preventing resonance. When the energy is relatively small and has a small amplitude, the reed switch 19 at the A and A' positions is opened and closed, and when the resonance energy is large and has a large amplitude, the reed switch 19 at the A and B' positions is opened and closed.

The hold circuit 8 that receives the detection signal from the above operation converts the detection signal into a pulse using a filter circuit. Now, if the pulses converted by this filter circuit are, for example, pulses like the signals A and B shown in FIG. 5, the NAND circuit 28 receiving these signals A and B converts the signals A, B is processed as a signal C that generates a positive pulse in response to the closing of the reed switch 19.

Subsequently, the retriggerable mono-multivibrator 29 that receives this signal C continues to operate for a certain period of time T from the pulse input and generates a signal D, and then returns to its own state. Since the retriggerable mono multivibrator 29 continues to operate and generate the signal D when the next pulse input is received, the retriggerable mono multivibrator 29 outputs the signal D as shown in FIG.

Next, a flip-flop circuit 30 following this retrievable mono multivibrator 29 is controlled by the activation signal and the inactivation signal of the retrievable mono multivibrator 29, and
It operates using the output signal from the NAND circuit 28 as a synchronization signal. That is, the flip-flop circuit 30 is
Under the input of the signal D, which is the activation signal from the retriggerable mono multivibrator 29,
A hold signal that transitions to a positive output state in synchronization with the signal C from the NAND circuit 28 when the signal C is input, and transitions back to the positive output state at the same time as the signal D of the retriggerable mono multivibrator 29 returns to zero. E and F (only the hold signal E is shown in FIG. 5) are output.

In the controller 9 that receives the hold signals E and F from the hold circuit 8, the damping force selection circuit 31 distinguishes the hold signals E and F, and the respective power transistors 32
Or under the control of 33, the damping force adjustment drive solenoid 36 or 37 of the damper mechanism 4 is selectively driven.
That is, when the resonance energy is relatively small and has a small amplitude, the damping force adjustment drive solenoid 36 is driven based on the hold signal E, and the damper mechanism 4
The damping force adjustment actuator such as the variable orifice is operated to slightly increase the generated damping force, and when the resonance energy is large and has a large amplitude, the hold signal F is selected and the damping force adjustment actuator is used to increase the generated damping force of the damper mechanism 4. Increase more.

As described above, the damper mechanism 4 automatically and appropriately responds to the occurrence and magnitude of sprung resonance and unsprung resonance in the suspension system of automobiles, etc.
The vibration damping effect is achieved by increasing the generated damping force.

Note that the damping force selection circuit 3 of the controller 9
In addition to the signal from the resonance detection sensor 7, the signal θ from the separately provided steering angle sensor 10 and the signal V from the vehicle speed sensor 10' (see Fig. 1) are input to 1.
By selectively or preferentially applying these signals θ and V, the damping force generated by the damper mechanism 4 during cornering is increased and anti-rolling against the vehicle body is achieved even when there is no vibration input from the road surface or with priority. It can also be used to perform functions.

〔Effect of the invention〕

As described above, according to the present invention, there is a resonance detection mechanism that detects the occurrence of resonance in spring vibration, a signal processing mechanism that holds the continuation state of resonance detected by the resonance detection mechanism, and a hold signal from the signal processing mechanism. The damping force of the damper is controlled by a drive mechanism that receives a signal and controls the damping force adjustment actuator of the damper mechanism, and increases the damping force generated by the damper mechanism only when resonance occurs to achieve an effective damping effect. This can significantly improve vehicle ride comfort.

Moreover, since the damping force control described above is a vibration frequency sensitive method using a resonance detection mechanism, it can be easily applied to existing vehicles such as automobiles that are equipped with dampers that can adjust the damping force.

In addition, by inputting vehicle speed, steering angle signals, etc. to the drive mechanism, and applying these signals selectively or preferentially in combination with input signals from the signal processing mechanism, the It has extremely high practical effects, such as increasing the damping force generated by the damper mechanism and suppressing rolling that occurs in the vehicle body.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of a frequency-sensitive shock absorber according to the present invention, and FIG. 2 is a longitudinal sectional view showing an example of a resonance detection mechanism in the frequency-sensitive shock absorber according to the present invention. 3 is a cross-sectional view taken along line A-A in FIG. 2, FIG. 4 is a circuit diagram showing an example of a signal processing mechanism in a frequency sensitive shock absorber according to the present invention, and FIG. FIG. 6 is a circuit diagram showing an example of a drive mechanism in a frequency-sensitive shock absorber according to the present invention; FIG. 7 is a configuration diagram showing a general vehicle suspension system; FIG. 8 is a frequency characteristic diagram of sprung mass acceleration in the suspension system. 1... Sprung vehicle body, 2... Unsprung mechanism,
3... Suspension spring, 4... Damper mechanism, 5
... Tire, 7 ... Resonance detection sensor which is a resonance detection mechanism, 8 ... Hold circuit which is a signal processing mechanism, 9 ... Controller which is a drive mechanism.

Claims (1)

[Scope of Claims] 1. In a vehicle suspension system equipped with a damper mechanism capable of adjusting damping force, a resonance detection mechanism detects the occurrence of resonance of spring vibration, and a continuation state of resonance detected by the resonance detection mechanism is held. A frequency-sensitive shock absorber comprising a damping force control device comprising a signal processing mechanism and a drive mechanism that receives a hold signal from the signal processing mechanism and controls a damping force adjustment actuator of the damper mechanism. 2. The frequency-sensitive shock absorber according to claim 1, wherein the resonance detection mechanism comprises a plurality of resonance detection sensors corresponding to a plurality of spring resonance frequencies. 3. The frequency-sensitive shock absorber according to claim 1, wherein the signal processing mechanism for holding the continuous state of resonance comprises a hold circuit that responds every half period of the resonance wave. 4. The driving mechanism according to claim 1, wherein the drive mechanism is configured to select and determine the damping force in response to each output signal obtained by detecting the magnitude of the input vibration amplitude in two stages by a resonance detection mechanism. Frequency sensitive shock absorber. 5. The frequency-sensitive shock absorber according to claim 1, wherein the damping force adjustment mechanism of the damper mechanism is a variable orifice provided in a piston moving in a cylinder. 6. Claim 1, in which a vehicle speed signal or a steering angle signal is added to the drive mechanism along with a hold signal.
Frequency-sensitive shock absorber as described in section.