JPH05286334A - Vibration reducer of vehicle - Google Patents

Abstract

PURPOSE:To reduce a so called steady point as a transmission function of the vibration acceleration of a car body to road input when the car body vibrates at a vibration frequency determined by the vibration of the car body, spring constant of a wheel and unsprung mass, in particular. CONSTITUTION:An auxiliary mass body 7 is arranged on the side (on spring) of the car body 1 of a vehicle, and a shaker 8 is also provided to shake the auxiliary mass body 7. The relative displacement between the car body 1 and a wheel 2FL is detected by a relative displacement sensor 10, and a relative speed signal is calculated from the detected signal. Based on a relative speed signal and relative displacement signal, the auxiliary mass body 7 is shaken with a shaker 8 in the direction to resist the vibration of the car body 1. The auxiliary mass body 7 comprises an engine and the shaker 8 comprises an engine mount. This effectively reduces the vibration of the car body while limiting the displacement quantity of the auxiliary mass body 7 small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a vehicle vibration reducing device.

[0002]

2. Description of the Related Art Conventionally, as a vehicle vibration reducing device,
A so-called active suspension device is known, for example, as disclosed in Japanese Patent Laid-Open No. 63-130418. This suspension device is provided with a fluid cylinder between a sprung portion and an unsprung portion of the vehicle, detects vertical acceleration and vehicle height applied to the vehicle, fluid pressure in the fluid cylinder, and the like, and based on these detection signals. By controlling the flow rate of the fluid supplied to and discharged from the fluid cylinder, each vibration of the bounce, pitching and roll of the vehicle is reduced regardless of the operating state of the vehicle.

Further, since the vibration of the vehicle body, especially the vibration associated with the unsprung resonance of the vehicle, is so-called bubbling and unpleasant vibration, conventionally, in order to reduce the unsprung vibration, the unsprung weight is reduced to reduce the unsprung resonance frequency. A method of optimizing by shifting to a high frequency side or adjusting a damping characteristic of a suspension device damper has been adopted.

[0004]

By the way, the active suspension device as described above, a semi-active suspension device in which only the damping constant of the damper is variable by simplifying the structure, or a normal suspension device in which the suspension characteristic does not change is provided. The vehicle can be represented by a two-degree-of-freedom model including an unsprung mass m1 and an unsprung mass m2, as shown in FIG.

Now, in the two-degree-of-freedom model of FIG. 8, the tire spring constant is KT, the road surface displacement is X0, and the unsprung displacement is X1.
, The sprung displacement is X2, and the reaction force of the suspension device is F
Then, the equation of motion is expressed by the following equation.

[0006]

[Equation 1]

[Equation 2] Based on the above equation, the transfer characteristic of the vibration from the road surface to the vehicle body (d
² x2 / dt ² ) / X0 becomes the graph shown in FIG.

Next, when the above equations (1) and (2) are added to eliminate the reaction force F,

[Equation 3] Is obtained, and by subjecting this formula to the Laplace transform and substituting S = jω, the following formula (3) is obtained.

[Equation 4] Next, let H (S) be the vibration transmission characteristic of the vehicle body, and H (S) = X2
Putting (S) · S ² / X0 (S), in the above formula (3),
Frequency transfer function H when ωa = √ (KT / m1)
(Ωa) is

[Equation 5] Becomes In the above formula (4), KT, m2 and ωa ²
Is a constant, so as shown in FIG. 10, ωa = √ (K
The transfer function H (ωa) of the frequency near 10 Hz, which is T / m1), is uniquely determined to be a constant value regardless of the type of suspension device. However, the transfer function H (ωa) of the frequency at ωa = √ (KT / m1) can be improved to be small, no matter how properly the damper is adjusted, the damper is adjusted, or the spring constant in the active suspension device is controlled. As a result, there was a limit to the reduction of vehicle vibration. For the above circumstances, see, for example, page 78 of “6. Design method of active suspension” described on pages 73 to 82 of the teaching materials of the Japan Society of Mechanical Engineers (Experience and vibration control of '91 -7.18,19). Is also disclosed, and the transfer function H (ωa) of the frequency when ωa = √ (KT / m1) is referred to as a fixed point. In this description, the transfer function H (ω
a) is called a fixed point.

Therefore, for example, in order to improve the fixed point H (ωa) to be small, theoretically from the above formula (4), the spring constant KT of the tire is limited to a small value, the sprung mass m2 is increased, or the spring mass is increased. Countermeasures such as setting a dynamic damper below may be considered, but none of them is a drastic solution, and has a drawback that the running property and durability of the vehicle are deteriorated.

The present invention has been made in view of the above point, and particularly focused on the structure of a vibration damping device for suppressing vibration due to strong wind using an auxiliary mass body in a high-rise building or the like. This damping device is used, for example, as a training material for the Japan Society of Mechanical Engineers ('91 -7.18,1
9) Experience / vibration control), page 1 to page 20, “1.
As disclosed in "Guidelines for Active Vibration Control System Design", two high-rise buildings that are built upright in parallel are connected by a passage or the like, and the passage is vibrated as an auxiliary mass body so that two It suppresses the vibration of high-rise buildings.

Therefore, the present inventor has considered a case where an auxiliary mass body is separately provided in the vehicle and the vehicle is represented by a three-degree-of-freedom model including a sprung mass, an unsprung mass, and an auxiliary mass body. That is,
In the three-degree-of-freedom model of the vehicle shown in FIG. 11, m3 is the mass of the auxiliary mass body arranged on the spring, Ks is the spring constant of the suspension device, Cs is the damping coefficient of the suspension device, and U is the addition mass to be added to the auxiliary mass body. If it is a vibrating force, the following three expressions are established.

[Equation 6]

[Equation 7]

[Equation 8] Here, in the above formula (6),

[Equation 9] That is,

[Equation 10] If the excitation force U to the auxiliary mass m3 is controlled so that the sprung mass acceleration can always be maintained at zero value and the fixed point H (ωa) can be eliminated regardless of the road surface input. I understood.

Therefore, generally, K1 and K2 are defined as control gains, and

[Equation 11] It is known that if the gains K1 and K2 are equal to the spring constant Ks and the damping coefficient Cs of the suspension device or set to a predetermined value, the sprung acceleration can be reduced and the fixed point H (ωa) can be improved.

From the above point of view, the object of the present invention is to improve the fixed point by providing the vehicle with the auxiliary mass body and appropriately oscillating the auxiliary mass body based on the above equation (8). The object is to provide a vibration reduction device for a vehicle that can be used.

[0013]

In order to achieve the above object, a concrete solving means of the invention according to claim 1 is, as shown in FIG. 1, an auxiliary mass body arranged in a sprung portion of a vehicle. 7, a vibrating means 8 for vibrating the auxiliary mass body 7, and a vibrating means 8 for vibrating the auxiliary mass body 7 with a value corresponding to a detection signal relating to the vibration of the vehicle body and an exciting force that opposes the vehicle body vibration. A control means 51 for controlling the vibrating means 8 is provided, and the auxiliary mass body is specified as an engine and the vibrator is specified as a mount of the engine.

Further, in the invention described in claim 2, in addition to the configuration of the invention described in claim 1, an operating state means for detecting a specific operating state of the engine is provided, and the operating state detecting means is provided to the control means. When the engine is in the specific operating state detected by the above, the function of changing the control gain of the vibration control of the auxiliary mass body to a small value is added.

Further, in the invention described in claim 3, the operating condition means of the invention described in claim 2 is specified to detect the acceleration operation of the engine.

[0016]

With the above construction, in the invention of claim 1,
Since the auxiliary mass body 7 is excited by the exciting force having a value corresponding to the detection signal regarding the vehicle body vibration, the exciting force close to the ideal exciting force determined by the above equation (8) is obtained, and As a result, the sprung acceleration of the vehicle is reduced, so that the fixed point H (ωa) is 1
The vibration of the vehicle is effectively reduced over a wide frequency range including a frequency near 0 Hz.

In this case, since the engine itself having a large mass is vibrated as the auxiliary mass body, the vehicle body vibration can be effectively reduced only by vibrating the engine with a small displacement amount.

Further, in the inventions according to claims 2 and 3, the control gain of the vibration control of the auxiliary mass body is changed to a small value by the control means in a specific operation state such as during acceleration operation of the engine. The mount allows the engine to be relatively strongly fixed, so that a large torque is transmitted to the driving wheels well, and the traveling performance such as the acceleration performance of the vehicle is secured well.

[0019]

As described above, according to the vibration reducing device for a vehicle of the first aspect of the present invention, the auxiliary mass body arranged in the vehicle is constituted by the engine itself, and the engine is provided with a detection signal relating to vehicle body vibration. Since it was excited by the engine mount with the excitation force according to, the displacement of the auxiliary mass body was limited to a small amount, and the vibration of the vehicle was effectively reduced over a wide frequency range including the frequency near 10 Hz of the fixed point. Therefore, there is an effect that the riding comfort of the vehicle can be improved.

According to the second and third aspects of the present invention, in addition to the structure of the first aspect of the invention, the auxiliary mass body is vibrated in a specific operation state such as during acceleration operation of the engine. Since the control gain of the control is changed to a small value, it is possible to ensure good transmission of large torque to the drive wheels, and it is possible to ensure good traveling performance such as acceleration performance of the vehicle.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

FIG. 2 shows a schematic structure of a vehicle vibration reducing apparatus according to the present invention. Although only the left side of the vehicle body is shown in the figure, the right side of the vehicle body is also similarly configured. In the figure, 1 is a vehicle body, 2FL is a left front wheel, 2FR is a left rear wheel, and coil springs 3 are provided between the vehicle body 1 and the left front wheel 2FL and between the vehicle body 1 and the left rear wheel 2FR, respectively. And damper 4
An ordinary suspension device 5 consisting of is interposed.

Further, an engine 7 is arranged in the hood of the vehicle body 1, and the engine 7 constitutes an auxiliary mass body 7 arranged at a sprung portion of the vehicle. The engine 7
Has a plurality of lower end portions fixed to the vehicle body 1 via an engine mount 8, and the mount 8 constitutes an exciter as a vibrating means for vibrating the engine 7 as an auxiliary mass body. ..

FIG. 3 shows the structure of the engine mount 8 as the above-mentioned vibrator. In the figure, the mount 8 has an outer peripheral end fixed to a casing 8b in which an insertion rod 8a to which a lower end portion of the engine 7 is fixed is arranged in an upper end portion, and a partition wall 8j arranged at a predetermined air gap in the inner periphery of the casing 8b. And a supporting portion 8d to which the inner peripheral end of the supporting rubber 8c is fixed,
The insertion rod 8e provided at the lower end of the support portion 8d is fixed to the vehicle body 1. A main liquid chamber 8f is formed in the casing 8b, and a sub liquid chamber 8i partitioned by a diaphragm 8h is formed outside the support rubber 8g. Main liquid chamber 8
The partition wall 8j in f has a relatively large-diameter flow port 8k formed in the upper portion thereof and a small-diameter flow port 8l at the lower end position thereof, and the main liquid chamber 8f and the sub liquid chamber 8i are formed. An orifice 8m is formed between the casing 8b and the partition wall 8j to squeeze the fluid through the small-diameter circulation port 8l while allowing the fluid to circulate through the two circulation ports 8k and 8l. Furthermore,
In the casing 8b, a vibration plate 8n forming the upper surface of the main liquid chamber 8f is slidably arranged and the vibration plate 8n is formed.
An electromagnetic actuator 8p that slides the vibrating plate 8n is disposed above the main plate, and the electromagnetic actuator 8p moves the vibrating plate 8n up and down to change the volume of the main liquid chamber 8f. The support rubber 8c is vertically vibrated by repeatedly circulating the fluid between the chamber 8f and the sub liquid chamber 8i through the orifice 8m. As for the support spring characteristic of the mount 8, if the spring constant is Kd and the mass of the engine 7 is md, 2> 1 / 2π√ ( Kd / md).

In addition, in FIG. 2, the auxiliary mass body 7 is
As a signal to be a basis for controlling the vibration of the vehicle body 1 in the vicinity of the suspension device 5 of the left front wheel 2FL and in the vicinity of the suspension device 5 of the left rear wheel 2FR, by detecting the cylinder stroke amount of the corresponding suspension device 5, Relative displacement sensors 10, 10 that detect the displacement of the left front wheel 2FL and the displacement of the vehicle body 1 and the left rear wheel 2FR, that is, the relative displacement between the sprung and unsprung portions of the vehicle, respectively, are arranged. A sprung acceleration sensor 11 for detecting the vertical acceleration of the vehicle body 1 is arranged. Further, the engine mount 8 of FIG. 3 is provided with a pressure sensor 12 that detects the hydraulic pressure in the main liquid chamber 8f.

Further, a stroke sensor 13 for detecting a stroke amount between the engine 7 and the vehicle body 1 is arranged near the engine 7.

The detection signals of the sensors 10 to 13 are input to a controller 15 having a CPU or the like inside, and the controller 15 controls the vibration of the engine 7.

The theory of vibration control of the engine 7 by the controller 15 will be described. First, a three-degree-of-freedom model of a vehicle in which the engine 7 is an auxiliary mass body and the engine mount 8 is an exciter is as shown in FIG. Now, assuming that the mass of the engine 7 is m3, the spring constant of the mount 8 is Kd, and the damping constant of the mount 8 is Cd, the following three expressions are established.

[Equation 12]

[Equation 13]

[Equation 14] In the above equation, the exciting force U to be applied to the engine 7 in order to bring the sprung acceleration of the vehicle to zero is given by the following equation.

[Equation 15] Generally, the control gains K1 to K4 are appropriately determined,

[Equation 16] The engine 7 is vibration-controlled by the vibration force U determined by.

Next, the controller 1 for performing the above vibration control
The internal configuration of No. 5 will be described based on the block diagram of FIG.
Since the configuration for each wheel is the same, the figure shows only one wheel. In the figure, 17 is a drive circuit, and the relative displacement sensor 1 to the drive circuit 17 is
In the input system of the detection signal of 0, a low-pass filter 20 for removing noise included in the relative displacement signal between the vehicle body 1 and the left front wheel 2FL, and only a high frequency band of 1 Hz or more of the signal from the low-pass filter 20 are input. A high-pass filter 21 for filtering, a phase adjusting circuit 22 for adjusting the phase A1 of the signal from the high-pass filter 21, and the phase adjusting circuit 2
And a relative speed signal between the vehicle body 1 and the left front wheel 2FL, that is, the spring of the vehicle, by differentiating the relative displacement signal after passing through the low pass filter 20. A differentiating circuit 24 for detecting the relative speed between the upper and the unsprung parts, and a high-pass filter 25 for sequentially filtering the signal from the differentiating circuit 24 at a high frequency, adjusting the phase A2, and adjusting the amplitude B2 in the same manner as described above. , A phase adjusting circuit 26, and an amplitude adjusting circuit 27 are provided.

Further, in the input system of the detection signal of the stroke sensor 13 to the drive circuit 17, noise included in the relative displacement signal between the auxiliary mass body (engine) 7 and the vehicle body 1 is removed as in the above. A low-pass filter 30, a high-pass filter 31 for filtering only a high frequency band of 1 Hz or higher of a signal from the low-pass filter 30, and a phase adjusting circuit 32 for adjusting the phase A3 and the amplitude B3 of the signal from the high-pass filter 21, respectively. And a amplitude adjusting circuit 33, and a differentiating circuit 34 for differentiating the relative displacement signal after passing through the low-pass filter 30 to detect the relative speed between the auxiliary mass body 7 and the vehicle body 1, and from the differentiating circuit 34. Signal of high frequency, high-pass filter 35 for phase A4 and amplitude B4 adjustment, phase adjustment circuit 36,
And an amplitude adjusting circuit 37.

Further, the low-pass filter 40 is also used in the input system of the detection signal of the sprung acceleration sensor 11 to the drive circuit 17.
An integrating circuit 41 that obtains a sprung speed signal by integrating the sprung acceleration signal from the low-pass filter 40; and an integrating circuit 41 disposed before and after the integration of the sprung acceleration signal and the sprung speed signal, respectively. Two high pass filters 42,
43 are provided.

Further, inside the controller 15, a signal phase / amplitude correction circuit 50 is provided. The correction circuit 50 includes a sprung acceleration d ² X 2 / dt ² and a sprung speed dX 2 / dt of the signal input system of the sprung acceleration sensor 11.
Based on the above, adjustment of each phase A to A4 by the phase adjustment circuits 22, 26, 32 and 36 of each signal input system of the relative displacement sensor 10 and the stroke sensor 13 so that these signal values become small, and Amplitude adjusting circuits 23, 27, 3
It has a function of outputting a correction signal for the adjustment of the amplitudes B1 to B4 by 3, 37.

Next, the vibration control of the auxiliary mass body 7 by the controller 15 will be described based on the control flow shown in FIG.

In the figure, start and step S
After monitoring the detection signals of each sensor in step 1, step S
2 differentiates the relative displacement X2-X1 signal between the vehicle body 1 and the wheels 2FL of the relative displacement sensor 10 to calculate the relative speed signal dX2 / dt-dX1 / dt between the vehicle body 1 and the left front wheel 2FL, and Vertical acceleration of the vehicle body 1 of the upper acceleration sensor 11
Integrating the d ² X 2 / dt ² signal, the sprung speed of the vehicle body 1
dX2 / dt is calculated, and the relative displacement signal X2-X3 of the stroke sensor 13 between the engine 7 and the vehicle body 1 is differentiated to obtain the relative velocity signal dX2 // between the engine 7 and the vehicle body 1.
Calculate dt-dX3 / dt.

[0035] Subsequently, the vertical acceleration d ² X2 / dt ² signal of the vehicle body 1 at step S3, and based on the vertical velocity dX2 / dt signal, the phase A1 to A4 and amplitude (control gain) B1 -B4 of each signal decide.

Then, in step S4, it is determined whether the engine 7 is in an accelerating operation state. This determination is based on whether or not the change in the throttle valve opening of the engine 7 is greater than or equal to a large set value when the gear position of the transmission mounted on the vehicle is the forward first speed or the second speed, or the third speed or This is performed depending on whether or not the change in the throttle valve opening at the fourth speed is equal to or larger than a small set value. Then, when the engine 7 is in the accelerating operation state, the amplitudes B1 to B4 determined above in step S5 are corrected to small values smaller than that value, and the process proceeds to step S6. On the other hand, when the engine 7 is not in the accelerating operation state, each amplitude B1 to B4
With the value determined above, the process proceeds to step S6.

After that, in step S6, the control signal value I1 for the electromagnetic actuator 8p of the vibrator 8 based on the relative speed dX2 / dt-dX1 / dt signal between the vehicle body 1 and the left front wheel 2FL is expressed by the following equation.

[Equation 17] And the control signal value I2 for the vibration exciter 8 based on the relative displacement X2-X1 signal between the vehicle body 1 and the left front wheel 2FL is calculated in the following formula in step S7.

[Equation 18] Based on the following equation, and then in steps S8 and S9, the relative speed between the engine 7 and the vehicle body 1 dX2 / dt-dX3
/ Dt signal and control signal value I3 for the electromagnetic actuator 8p of the vibrator 8 based on the relative displacement X2-X3 signal, respectively
And I4 are respectively expressed by the following equations.

[Formula 19]

[Equation 20] Calculate based on.

After that, in step S10, the control signal values I1 to I4 are added to calculate a total control signal value I, and the signal value I is calculated by the electromagnetic actuator 8 of the vibrator 8.
Output to p and return.

Therefore, in the control flow of FIG.
The step S4 constitutes the operating state detection means 52 for detecting the accelerated operating state of the engine 7, and the steps S5 to S9 of the control flow form a relative speed dX2 / dt-dX1 between the vehicle body and the wheels concerning the vehicle body vibration. / Dt, relative displacement X2-X1, relative speed between engine and vehicle body dX
The control current values I1 to I4 having values corresponding to the 2 / dt-d X3 / dt and the relative displacement X2-X3 signals are calculated, and the current value I1 is calculated.
To the driving state detecting means 52 while controlling the vibration exciter (mount) 8 so as to vibrate the auxiliary mass body (engine) 7 so as to oppose the vibration of the vehicle body 1 by the vibration force having a value corresponding to I4. The control means 51 is configured to change the control gains (amplitudes) B1 to B4 to a value smaller than the normal value when the engine 7 is in the acceleration operation state detected by.

Therefore, in the above embodiment, the vertical acceleration d ² X 2 / dt ² and the vertical speed dX 2 / dt of the vehicle body 1 are increased.
Based on the following, the phases A1 to A4 and the amplitude B1 of the AC control signal are
After determining B4, the relative speed between the vehicle body and the wheels relating to vehicle body vibration, dX2 / dt-dX1 / dt, and the relative displacement X2-X1.
, Relative velocity between engine and vehicle body d X2 / dt-d X3 / d
Control signal I1 based on t and the relative displacement X2-X3 signal
.About.I4 are calculated, and the electromagnetic actuator 8p of the vibrator 8 is excited by the control signal value I obtained by summing these values. Therefore, the exciting force U expressed by the following equation acts on the auxiliary mass body 7 in a direction opposing the vibration of the vehicle body 1,

[Equation 21] Since the force acting on the vehicle body 1 is offset, the vibration of the vehicle body 1 is effectively reduced.

FIG. 6 shows the result of simulating the degree of reduction of vehicle body vibration according to the invention of claim 1 of the present application. According to the figure, it can be seen that the vibration can be effectively reduced in the band of 2 Hz or higher. Therefore, the invention according to claim 1 of the present application has an effect of effectively reducing the vibration of the vehicle body at the frequency of the fixed point near 10 Hz, which could not be conventionally reduced.

Moreover, the mass of the engine 7 is large. Therefore, when the engine 7 is vertically vibrated in accordance with the vibration of the vehicle body,
A small amount of displacement to vertically displace the engine 7 is sufficient, which is effective in reducing vehicle body vibration.

Moreover, when the engine 7 is in an accelerating operation state, the control gains B1 to B4 are changed to a value smaller than the normal value, and the vertical vibration operation by the mount 8 of the engine 7 is restricted. The engine 7 is strongly fixed to the vehicle body 1 by the mount 8. As a result, the large torque of the engine 7 is satisfactorily transmitted to the drive wheels, and the acceleration performance of the vehicle is ensured satisfactorily.

In the above embodiment, the vibrator 8 is of the electric type, but it may of course be of hydraulic type.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an invention according to claim 1.

FIG. 2 is a diagram showing an overall schematic configuration.

FIG. 3 is a diagram showing a specific configuration of a vibration exciter.

FIG. 4 is a block configuration diagram inside a controller.

FIG. 5 is a flowchart showing vibration control of an auxiliary mass body.

FIG. 6 is a diagram showing the degree of the effect of the invention according to claim 1;

FIG. 7 is a diagram showing a three-degree-of-freedom model of a vehicle when an engine is used as an auxiliary mass body.

FIG. 8 is a diagram showing a two-degree-of-freedom model of a vehicle.

FIG. 9 is a diagram showing riding comfort characteristics of a conventional suspension device.

FIG. 10 is an explanatory diagram of a fixed point.

FIG. 11 is a diagram showing a general three-degree-of-freedom model of a vehicle.

[Explanation of symbols]

 1 Vehicle Body 2FL, 2FR Wheels 7 Engine (Auxiliary Mass Body) 8 Engine Mount (Vibration Means) 8c Support Rubber 8m Orifice 10 Relative Displacement Sensor 11 Vertical Acceleration Sensor 13 Stroke Sensor 51 Control Means 52 Operating State Detection Means

Claims (3)

[Claims] 1. An auxiliary mass body arranged at a sprung portion of a vehicle, and a vibrating means for vibrating the auxiliary mass body, and having a value according to a detection signal relating to vehicle body vibration and counteracting the vehicle body vibration. With the control means for controlling the vibration means to reduce the vehicle body vibration so as to vibrate the auxiliary mass body with the exciting force to perform, the auxiliary mass body is an engine,
A vibration reducer for a vehicle, wherein the vibration exciter is a mount of the engine. 2. An operating state means for detecting a specific operating state of the engine, wherein the control means sets a control gain for excitation control of the auxiliary mass body in the specific operating state of the engine detected by the operating state detecting means. The vibration reduction device for a vehicle according to claim 1, wherein the vibration reduction device is changed to a small size. 3. The vibration reducing apparatus for a vehicle according to claim 2, wherein the operating state means detects when the engine is in an accelerating operation.