JP3085694B2 - Vehicle suspension device - Google Patents

Description

The present invention relates to a vehicle suspension device, and more particularly, to a vehicle suspension device.
The present invention relates to a suspension device that changes suspension characteristics by supplying and discharging a working fluid to and from a cylinder provided between a vehicle body and wheels.

(Prior Art) For example, as shown in Japanese Patent Application Laid-Open No. 63-130418, a hydraulic cylinder is provided between a vehicle body and a wheel, and the supply and discharge of a working fluid to and from this cylinder are controlled to thereby provide suspension characteristics. A suspension device for a vehicle that allows the vehicle to be freely changed is known.

In this type of so-called active control suspension device, the roll during turning of the vehicle is suppressed,
Alternatively, various controls such as suppressing the pitching of the vehicle can be performed.

(Problems to be Solved by the Invention) By the way, the above-mentioned pitching often occurs when the vehicle starts, or when the shift speed of the transmission is shifted. The former is generally referred to as a starting Scott, and the latter is referred to as a shifting Scott.

In order to suppress this shifting Scott, the spring constant and damping force should be set so as to be large, but when it receives low-frequency and high-frequency vibrations, the riding comfort of the vehicle is so-called rugged. It will be.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle suspension device that can prevent shift scott and can also provide a comfortable ride without ruggedness. Is what you do.

(Means for Solving the Problems) A vehicle suspension device according to claim 1 of the present invention is provided between a vehicle body and wheels of a vehicle provided with an automatic transmission having a power mode / econo mode switching function. Receiving a shift command information of an automatic transmission in a vehicle suspension device comprising a hydraulic cylinder having a hydraulic cylinder and a controller for controlling supply and discharge of a working fluid to the cylinder so as to suppress at least pitching of the vehicle body. Correction means for temporarily increasing the gain of control for suppressing pitching in synchronization with the shift timing, wherein the correction means compares the amount of increase in the control gain during power mode traveling with respect to the economy mode traveling. It is characterized in that it is configured to be large.

In many cases, the active control suspension device includes a vertical acceleration sensor that detects a vertical acceleration of a vehicle body and a vehicle height sensor that detects a vehicle height of each wheel, and the controller indicates the vertical acceleration sensor. The first control for canceling the vertical acceleration and the second control for canceling the vehicle high speed based on the output of the vehicle height sensor are configured to suppress the pitching.

In a case where the present invention is applied to a suspension device having such a configuration, a liquid installed between a vehicle body and wheels of a vehicle provided with an automatic transmission as in a vehicle suspension device according to claim 2 of the present invention. A pressure cylinder, and a controller for controlling supply and discharge of a working fluid to and from the cylinder so as to suppress at least pitching of the vehicle body. Correction means for receiving gear shift command information and temporarily increasing the gain of control for suppressing pitching in synchronization with gear shift timing, wherein the correction means controls the vehicle speed when the vehicle speed is lower than a predetermined vehicle speed. The amount of increase in gain can be configured to be larger than the amount of increase in the control gain when the vehicle speed is higher than the predetermined vehicle speed.

Further, as in a vehicle suspension device according to a third aspect of the present invention, a hydraulic cylinder installed between a vehicle body and wheels of a vehicle having an automatic transmission is provided so as to suppress at least pitching of the vehicle body. And a controller for controlling supply and discharge of the working fluid to and from the cylinder. The suspension device receives a shift command information of an automatic transmission and temporarily suppresses pitching in synchronization with a shift timing. Correction means for increasing a control gain is provided, wherein the correction means is configured to control a shift in the automatic transmission between a first shift speed and a second shift speed higher than the first shift speed. The amount of increase in the control gain at the time of the shift is determined by the control at the time of the shift from the second shift speed to the third shift speed higher than the second shift speed. It can be configured to be larger than the increase amount of the control gain.

(Operation and Effect of the Invention) If the gain of the control for suppressing the pitching is increased in synchronization with the shifting timing, the active control is made more responsive to the pitching, and the shifting scott can be prevented.

In this case, since the response of the pitching control is increased, the response to the bounce and the pitching is the same as usual, so that the influence on the riding comfort can be minimized and the response is increased. Since a large amount is only for pitching as a vehicle body, oscillation phenomena and the like accompanying a response delay of control can be prevented as much as possible.

On the other hand, the control gain at the time of shifting or higher can be set to a value lower than the value at the time of shifting without particularly considering the shifting scott, so that the ride comfort of the vehicle is impaired by low-frequency and high-frequency vibrations. It will not be.

Further, when the automatic transmission is set to the power mode, the torque of the transmission output shaft, that is, the driving force of the drive wheels is larger than in the econo mode, and shift Scott is more likely to occur. Therefore, in the power mode, if the increase correction amount of the control gain is made larger as in the device according to the first aspect, it is possible to reliably prevent the shift scotch which tends to become remarkable.

Then, in the econo mode in which shift Scott is relatively unlikely to occur, if the increase correction amount of the control gain is made smaller, the influence on the riding comfort when the vehicle receives low-frequency vibration can be further reduced. .

On the other hand, when the vehicle speed is relatively low, the driving force of the drive wheels is generally larger than when the vehicle speed is relatively high. Similarly, when a relatively low speed shift range is selected,
Generally, the driving force of the drive wheels is larger than when a relatively high speed shift range is selected.

Therefore, in the case where the driving force is large and the shift Scott is more likely to be generated as described above, claim 2
If the gain increase correction is performed in all of the controls relating to pitching suppression as in the device described in No. 3, it is possible to reliably prevent a shift scotch that tends to be noticeable.

Then, at a relatively high vehicle speed where shift Scott is relatively unlikely to occur, or when a relatively high speed shift range is selected, the gain increase correction is performed in only one of the controls relating to pitching suppression. Then, the influence on the riding comfort when the vehicle receives low-frequency and high-frequency vibrations can be further reduced.

(Examples) Hereinafter, the present invention will be described in detail based on examples shown in the drawings.

FIG. 1 shows a vehicle suspension device according to an embodiment of the present invention, and FIG. 2 shows a hydraulic circuit used in the suspension device. In the figure, the main elements corresponding to the right front wheel, the left front wheel, the right rear wheel and the left rear wheel are indicated by adding the reference numerals “FR”, “FL”, “RR” and “RL” to the respective numbers. In the following description, these symbols will be attached only when particularly necessary.

As shown in FIG. 1, a hydraulic cylinder 12 is fixed to a vehicle body 11 for each wheel, and a hydraulic chamber 14 is defined by a piston 13 slidably fitted in the hydraulic cylinder 12. Have been. The wheel 10 is held by a piston rod 15 integrated with the piston 13. A gas spring 21 communicates with the hydraulic chamber 14 via a hydraulic passage. The gas spring 21 has a gas chamber 25 and a liquid chamber 27 defined by a diaphragm 23 as a movable partition, and the liquid chamber 27 is passed through the hydraulic chamber 14.

In addition, as shown in detail in FIG.
Two wheels 21 are provided for each wheel, and they are connected to the hydraulic cylinder 12 in a parallel relationship with each other. An orifice 29 is provided in each of the hydraulic passages 18 communicating with each of the gas springs 21. The unit composed of such a combination of the hydraulic cylinder 12, the gas spring 21, and the orifice 29
With the 29 damping action, a basic function as a suspension device is provided.

A high-pressure pipe 31F or 31R is connected to the above-mentioned hydraulic cylinder 12, and supply and discharge of hydraulic fluid to and from the hydraulic cylinder 12 are performed through these pipes. The high pressure pipe
Flow control valves 9F and 9R are interposed in 31F and 31R, respectively, and these flow control valves 9 control the supply and discharge of the hydraulic fluid to and from each cylinder 12 to adjust the cylinder internal pressure.

Hereinafter, a hydraulic circuit for supplying and discharging the hydraulic fluid will be described with reference to FIG. The vane pump 32 driven by the engine 80 supplies hydraulic fluid from the reservoir tank 33.
The pump 44 is pumped up, and the hydraulic fluid 44 is pumped through the common high-pressure pipe 34 to the high-pressure pipes 31F and 32R for the front wheels and the rear wheels. A check valve 35, a filter 36, a main accumulator 37 for accumulating pressure,
And an oil pressure gauge 38 are provided. When the discharge-side pressure rises abnormally, the pump 32 discharges hydraulic fluid
An in-pump relief valve 30 for returning the 44 to the suction side is provided.

The high-pressure pipe 31F for the front wheel is branched into a high-pressure pipe 31FR for the right front wheel and a high-pressure pipe 31FL for the left front wheel.
FL is an inflow valve 52 constituting the flow control valves 9FR and 9RL, respectively.
The hydraulic chambers 14 of the front right wheel hydraulic cylinder 12FR and the left front wheel hydraulic cylinder 12FL are communicated with each other via FR and 52FL. The flow control valve 9 includes the above-described inflow valve 52 and a discharge valve 53 interposed in a return pipe 40F for returning the hydraulic fluid 44 to the reservoir tank 33. Each of the inflow valve 52 and the discharge valve 53 can be in an open position and a closed position, and has a built-in differential pressure valve that maintains the hydraulic pressure at the open position at a predetermined value.

A pilot passage 39F branches off from the high-pressure pipe 31F, and the pilot communication 39F is connected to pilot pressure-responsive check valves 50FR and 50FL. Each check valve 50
Receives the operating oil pressure (accumulated oil pressure by the main accumulator 37: main pressure) in the high-pressure pipe 31 on the upstream side of the inflow valve 52 through the pilot passage 39F, and closes when the pilot pressure is less than, for example, 40 kgf / cm ² Has become.
That is, supply and discharge of the hydraulic fluid to and from the hydraulic cylinders 12FR and 12FL can be performed only when the main pressure is 40 kgf / cm ² or more.

Further, a relief valve 54FR and a hydraulic pressure gauge 55FR are interposed in the right front wheel high pressure pipe 31FR. On the other hand, the left front wheel high pressure pipe 31
The FL is also provided with a relief valve 54FL and a hydraulic pressure gauge 55FL. Relief valves 54FR and 54FL are hydraulic cylinders 12FR and 12FL
It is opened when the internal pressure of the oil tank rises abnormally, and the hydraulic oil 44 is returned to the return pipe 40F. The recirculation passage 40F has a hydraulic cylinder 12
A return accumulator 59F that performs a pressure accumulating function when the hydraulic fluid 44 is discharged from FR and 12FL is attached.

The same elements as the above-described respective elements for the front wheel are provided also on the rear wheel high-pressure pipe 31R side. In FIG. 2, the front wheel element and the rear wheel element that are equivalent to each other are distinguished from each other by the symbols “F” and “R” added after the respective numbers.

The front-wheel-side reflux pipe 40F and the rear-wheel-side reflux pipe 40R are connected to a common reflux pipe 41 that reaches the reservoir tank 33 via a cooling circuit 46. The common reflux pipe 41 and the common high-pressure pipe 34 communicate with each other via a relief pipe 42, and an unload valve 43 is provided in the relief pipe 42.
The operation of the unload valve 43 is controlled by a control unit 45 (see FIG. 1) which receives the output of the oil pressure gauge 38, and the main pressure is set to a predetermined upper limit (for example, 160 kgf / c).
When the pressure exceeds m ² ), the vane pump 32 is opened to bring the vane pump 32 into an unload state, and this state is maintained until the main pressure becomes equal to or lower than a predetermined lower limit (for example, 120 kgf / cm ² ). Then, when the main pressure falls below the lower limit, the control unit 45 closes the unload valve 43 and puts the vane pump 32 into a loaded state. Thereby, the main pressure rises to the upper limit.
Thus, the main pressure is maintained in a predetermined range (120 to 160 kgf / cm ² ).

Further, the common reflux pipe 41 and the common high-pressure pipe 34 are communicated by a relief pipe 47, and a fail-safe valve 48 is interposed in the relief pipe 47. The fail-safe valve 48 is switched to the open position when another valve or the like fails, and stores the oil stored in the main accumulator 37 in the reservoir tank 33.
To release the high pressure state. The pilot passage 39F has a throttle that delays the closing operation of the check valves 50FR and 50FL when the fail-safe valve 48 is opened.
51F is provided.

Next, the operation of the suspension device having the above configuration will be described. Unload valve 43, fail-safe valve 48, inflow valve
The operation of the outflow valve 53 is controlled by a control unit 45 composed of, for example, a microcomputer. The control unit 45 includes the hydraulic pressure gauge 38, a hydraulic pressure gauge 55 provided for each hydraulic cylinder 12, and the front wheels 10FR and 10FL.
And three vertical acceleration sensors 57 for detecting sprung acceleration for each rear wheel 10R, four vehicle height sensors 58 for detecting vehicle height (ie, cylinder stroke) for each wheel 10FR, 10FL, 10RR, and 10RL, and A lateral acceleration sensor 61 for detecting the applied lateral acceleration, an output of a vehicle speed sensor 62, and a signal indicating the state of the automatic transmission 81 are input (in FIG. 1, a hydraulic gauge 55 and a vehicle height sensor 58). About left rear wheel 10
Only those corresponding to RL and those corresponding to the rear wheel 10R for the vertical acceleration sensor 57 are shown).

The control unit 45 includes a hydraulic pressure gauge 5 for each wheel.
5, the vertical acceleration sensor 57 for each of the left and right front wheels and the rear wheel, the vehicle height sensor 58 for each wheel, and the lateral acceleration sensor 61 indicate the cylinder internal pressure, sprung acceleration, vehicle height, and lateral speed, respectively. The supply and discharge of the hydraulic oil 44 is controlled.
By supplying / discharging the hydraulic oil to / from the hydraulic cylinder 12, the same operation as changing the throttle resistance of the orifice 29 and the elastic modulus of the gas spring 21 is obtained, and the suspension device is a so-called active suspension device. Function. Further, it is also possible to control the amount of hydraulic fluid in the hydraulic cylinder 12 to control the vehicle height for each wheel.

Next, variable control of suspension characteristics by the control unit 45, that is, supply / discharge control of hydraulic fluid to each hydraulic cylinder 12, will be described with reference to FIGS. 3A to 3D.

The control unit 45 of the present embodiment basically controls the vehicle height to the target vehicle height (the cylinder stroke amount to the target amount) based on the detection signal of the vehicle height sensor 58 for each wheel.
A control system A shown in FIG. 3 and a control system B shown in FIG. 3B for reducing vertical vibration of the vehicle body 11 based on a vehicle high speed signal obtained by differentiating a detection signal of the vehicle height sensor 58; A control system C shown in FIG. 3C for reducing vertical vibration of the vehicle body 11 based on a detection signal of the vertical acceleration sensor 57, and a hydraulic gauge 55 for each wheel.
The control system D shown in FIG. 3D for equalizing the supporting load between the left and right wheels on the front wheel side and the rear wheel side based on the detection signal of FIG.
And

Bounce control section 70 in the above control system A, of the output from the vehicle height sensors 58, right and left front wheels 10FR, output X _FR for 10FL, the right and left rear wheels 10RR with summing X _FL, outputs X _RR for 10RL, by summing X _RL, it calculates the bounce component of the vehicle body 11. Then, the bounce control unit 70 calculates a control amount for the flow control valve 9 of each wheel in the bounce control based on the calculated bounce component, for example, by PD (proportional-differential) control.

The pitch control unit 71, the left and right front wheels 10FR, output X _FR of 10FL side, the sum of X _FL, left and right rear wheels 10RR, 10RL side of the output X _RR, by subtracting the sum of X _LR, body Calculate 11 pitch components. Then, the pitch control unit 71 calculates a control amount of each flow control valve 9 in the pitch control by, for example, PD control based on the calculated pitch component.

Further, the roll control unit 72 adds the output difference X _FR -X _FL of the left and right front wheels 10FR and 10FL and the output difference X _RR -X _RL of the left and right rear wheels 10RR and 10RL, and Calculate the roll component. The roll control section 72, the computed roll component, and enter example PD target roll angle T _R of the vehicle body 11
Controlled by, so to vehicle height which is inclined to the target roll angle T _R, calculates the control amount of each flow control valve 9 in the roll control.

And in order to control the vehicle height to the target vehicle height, the control unit 70,
Multiply the control amounts calculated in 71 by the coefficients K _B1 and K _P1 respectively,
The control amounts calculated by the roll control unit 72 are multiplied by coefficients K _RF1 and K _RR1 on the front wheel side and the rear wheel side, respectively, and the values are inverted for each wheel (in the positive and negative directions of the signal input of the vehicle height sensor 58). after reversed) in the opposite direction to the bounce for the wheels, pitch, and adds the control amount of the roll, and the controlled variable _{Q FR1, Q FL1, Q RR1} , Q RL1 of corresponding flow control valve 9 .

In the control system B, the pitch control unit 73 outputs vehicle high-speed signals X _FR , Y _FL , and Y _RR obtained by differentiating the outputs X _FR , X _FL , X _RR , and X _RL of the four vehicle height sensors 58. , Y _RL , left and right front wheels 10F
The pitch component of the vehicle body 11 is calculated by subtracting the sum of the signals Y _RR and Y _RL on the left and right rear wheels 10RR and 10RL from the sum of the signals Y _FR and Y _FL for R and 10FL. And the pitch control unit 73
Calculates the control amount of each flow control valve 9 in the pitch control by, for example, PD control based on the calculated pitch component.

The roll control unit 74 also adds the difference Y _FR -Y _FL between the left and right front wheels 10FR and 10FL, and the difference Y _RR -Y _RL between the left and right rear wheels 10RR and 10RL to obtain the vehicle body 11. Calculate the roll component. Then, the roll control unit 74 calculates a control amount of each flow control valve 9 in the roll control by, for example, PD control based on the calculated roll component.

Then, the control amount calculated by the pitch control unit 73 is multiplied by a coefficient K _P2 so that the vehicle high speed converges, and the control amount calculated by the roll control unit 74 is increased by a coefficient on the front wheel side and the rear wheel side.
After multiplying K _RF2 and K _RR2 and inverting those values for each wheel (inverting in the opposite direction to the positive and negative directions of the signal input of the vehicle height sensor 58), the control amounts of the pitch and roll for each wheel are calculated. The control amounts Q _FR2 , Q _FL2 ,
_Let Q _RR2 and _QRL2 .

In the control system C, bounce control section 75, the output G _FR, G _FL of the three vertical acceleration sensors 57, sums the G _R calculates the bounce component of the vehicle, based on the calculated bounce component For example, by IPD control (integral-proportional-differential control), the control amount for the flow control valve 9 of each wheel in the bounce control is calculated.

The pitch control unit 76, among the three vertical acceleration sensors 57, right and left front wheels 10FR, 10FL side of the output G _RR, by subtracting the output G _R of the rear wheel 10R side from the average value of the G _FL, body 11 Is calculated, and the control amount of each flow control valve 9 in the pitch control is calculated by the same integral-proportional-differential control based on the calculated pitch component.

The roll control section 77, the output G _FR of the right front wheel 10FR side, by subtracting the output G _FL of the left front wheel 10FL side, calculates the roll component of the vehicle body 11, as described above on the basis of the calculated roll component , The control amount of each flow control valve 9 in the roll control is calculated.

Then, the control amounts calculated by the control units 75 and 76 are multiplied by coefficients K _B3 and K _P3 , respectively, so that the vertical vibration of the vehicle body 11 is suppressed by the bounce component, the pitch component, and the roll component. The calculated control amounts are multiplied by the coefficients K _RF3 and K _RR3 on the front wheel side and the rear wheel side, and the values are inverted for each wheel (inverted in the opposite direction to the positive and negative directions of the signal input of the vertical acceleration sensor 57). After that, bounce, pitch,
By adding respective control amounts of the roll, the control amount Q _FR3 of the corresponding flow control valves 9, Q _FL3, and Q _RR3, Q _RL3.

Further, in the control system D, the warp control unit 78 inputs the outputs P _FR and P _FL of the two hydraulic gauges 55 on the front wheel side, and obtains the fluid pressure of the left and right wheels with respect to the total hydraulic pressure on the front wheel side (P _FR + P _FL ). Pressure differential (P _FR
-P _FL ), and includes a front-wheel-side load transfer ratio calculation unit 78F that calculates the same load transfer ratio on the rear wheel side. Then, after multiplied by a coefficient omega _F of the load movement ratio of the rear wheel side, subtracts this from the load transfer ratio of the front wheel side, since the predetermined multiple the results by a factor of omega _A, the front wheel side by the coefficient omega _C Weighting, then invert the control amount for each wheel to equalize between the left and right wheels,
Corresponding control _variables Q _FR4 , Q _FL4 , Q _RR4 , _{QRL4 of} the flow control valve 9
And

Note that, in addition to the control systems A, B, C, and D described above, a control system for canceling the lateral acceleration detected by the lateral acceleration sensor 61 and the like are also provided, but description thereof will be omitted.

Next, a process for preventing shift scott will be described. FIG. 4 shows the flow of this processing by the control unit 45. As shown in the figure, the control unit 45 inputs the shift information of the automatic transmission 81 in step P1, and then in step P2, the vehicle speed sensor
The vehicle speed v indicated by the output of 62 is input.

Next, in Step P3, the control unit 45
It is determined whether or not a shift command for the automatic transmission 81 has been issued. If this shift command has not been issued, step P13
, The coefficients K _B1 , K _P1 , K _RF1 , K K shown in FIGS. 3A to 3D
_{RR1, K P2, K RF2,} K RR2, K B3, K P3, K RF3, K RR3, ω F,
ω _A and ω _C are all determined according to a predetermined map.

In this map, for example, as shown in FIG. 5, modes corresponding to the lateral acceleration and the vehicle speed v are set, and coefficients in each mode are determined. In this embodiment, in addition to the mode shown in FIG.
Mode 1 when the vehicle is stopped and mode 2 when the vehicle is stopped. FIG. 6 shows some examples of the coefficients in each mode. The unit of the coefficient / (mm / sec) in FIG. 6 is a unit for supplying and discharging one hydraulic fluid 44 when the above-mentioned vehicle high speed is around 1 mm / sec, and / G is the vertical acceleration 1G. This is a unit that supplies and discharges one hydraulic oil 44 per unit.

On the other hand, when it is determined in step P3 that a gearshift command has been issued, the control unit 45 next determines in step P4 whether the vehicle speed v is equal to or higher than 40 km / h. If so, the control unit 45 next increases the coefficient K _P3 , which is one factor for determining the control gain of the pitching suppression, to 17 / G from the normal value defined by the map in step P5. In this case, the vehicle speed v
Since the speed is 40 km / h or more, modes 4, 5, 6, or 7 are set as can be seen from FIG. 5, and therefore, the normal value of the coefficient K _P3 is 12 or 15 / G.

Next, in step P6, the control unit 45 determines whether or not a predetermined time has elapsed after increasing the coefficient K _P3 , and when this time has elapsed, the process returns to step P1.

As described above, when the speed change operation is performed in the automatic transmission 81, if the gain of the pitching suppression control is temporarily increased in synchronization with the speed change operation, the active control becomes more responsive to pitching as described above. Well done, shifting scott can be prevented.

On the other hand, the control gain other than during the shift can be set to a value lower than the value during the shift without particularly considering the shift scott, so that the ride comfort of the vehicle is impaired by low-frequency vibration. Nor.

When it is determined in step P4 that the vehicle speed v is less than 40 km / h, the control unit 45 next determines in step P7 whether 0 <v <40 km / h. Otherwise, that is, when the vehicle is stopped, the processing flow proceeds to Step P13, and each coefficient is determined according to the above-described map.

If the vehicle is not stopped, control unit 45
Next, in step P8, it is determined whether or not the automatic transmission 81 is set to the power mode. This automatic transmission
Reference numeral 81 is selectively switched to one of the power mode in which a relatively large reduction ratio is set at each gear and the econo mode in which a relatively small reduction ratio is set. When it is determined in step P8 that the power mode is set, the control unit 45
In step P9, the coefficient K _P3 is increased from the normal value (10 or 12 / G in this case: see FIGS. 5 and 6) determined by the aforementioned map to 15 / G, and the coefficient K _P2 is It is increased to 0.05 / (mm / sec) from the determined normal value (in this case, zero: see FIGS. 5 and 6).

The above coefficient K _{P2 is} also one element that determines the control gain of the pitching suppression, and the coefficient K _P2 and the coefficient K _P2 are determined.
By increasing _P3 , it is also possible to prevent shifting scott in this case.

Next, in step P10, when it is determined that the predetermined time has elapsed after increasing the coefficients K _P2 and K _P3 , the process for preventing the shifting scott returns to step P1.

On the other hand, when it is determined in step P8 that the automatic transmission 81 is not set to the power mode, that is, it is determined that the economy mode is set, the coefficients K _P2 and K _P3 are set to normal values in step P11. From 0.03 /
(Mm / sec), increased to 13 / G.

Next, in step P12, if it is determined that the predetermined time has elapsed after increasing the coefficients K _P2 and K _P3 , the process for preventing the shift scott returns to step P1.

As described above, in the power mode running in which the driving force of the vehicle is relatively large and shift Scott is likely to occur, the coefficients K _P2 and K _P3 are increased more than in the _econo mode running, so that the power mode running is performed. Also, it is possible to reliably prevent the shifting scott. When the vehicle is traveling in the Econo mode where shift Scott is relatively unlikely to occur, the coefficients K _P2 and K _{P2
By making} the increase width of _P3 relatively small, a better ride comfort can be obtained.

When the vehicle speed v is as high as 40 km / h or higher and shifting scott is relatively unlikely to occur, only the coefficient K _P3 is increased (step P5), whereas the vehicle speed v is lower than 40 km / h and the speed is low. If the Scott relatively easily occur, since the addition coefficient K _P2 be added to the coefficient K _P3 increases (step P9 and P11), also in this case it is possible reliably prevent shifting Scott. At the time of high-speed running in which shift Scott is relatively unlikely to occur, only the coefficient K _P3 is increased, so that a better riding comfort can be obtained.

In place of steps P4 and P7 of the process shown in FIG. 4,
Steps P20 and P21 as shown in FIG. 7 may be provided. That is, in this case, only the coefficient K _P3 is increased at the time of a shift operation between high gears (second gear and third gear) where shift Scott is relatively unlikely to occur. During the speed change operation, the coefficient K _P2 is increased in addition to the coefficient K _P3 .

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a suspension device according to an embodiment of the present invention. FIG. 2 is a circuit diagram showing a hydraulic circuit used in the suspension device. FIGS. 3A, 3B, 3C and 3D show suspension diagrams. FIG. 4 is a control block diagram showing variable control of characteristics, FIG. 4 is a flowchart showing shift Scott prevention control in the suspension device, FIG. 5 is an explanatory diagram showing a mode setting area of characteristic variable control in the suspension device, FIG. FIG. 7 is a table showing the values of the coefficients relating to the characteristic variable control for each mode, and FIG. 7 is a flowchart showing another example of the shift Scott prevention control. 10 ... wheels, 11 ... body 12 ... hydraulic cylinder, 13 ... piston 14 ... hydraulic chamber of hydraulic cylinder 15 ... piston rod, 18 ... hydraulic passage 21 ... gas spring, 31 ... … High pressure pipe 32… Pump, 37, 59… Accumulator 38, 55… Hydraulic gauge, 39… Pilot passage 40… Reflux passage, 43… Unload valve 44 …… Hydraulic fluid, 45 …… Control Unit 48 Fail-safe valve, 52 Inflow valve 53 Outflow valve 57 Vertical acceleration sensor 58 Vehicle height sensor 61 Lateral acceleration sensor 62 Vehicle speed sensor 80 Engine 81 …… Automatic transmission

Continuation of the front page (72) Inventor Jiro Kondo 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Examiner, Mazda Co., Ltd. Kazumi Kawamukai (56) References JP-A-2-155817 (JP, A) (58) ) Surveyed field (Int.Cl. ⁷ , DB name) B60G 17/015

Claims (3)

(57) [Claims] 1. A hydraulic cylinder installed between a vehicle body and a wheel of a vehicle having an automatic transmission having a power mode / econo mode switching function, and the hydraulic cylinder being provided so as to suppress at least pitching of the vehicle body. And a controller for controlling supply and discharge of a working fluid to a vehicle. The suspension gain of control for temporarily suppressing pitching in synchronization with a shift timing, receiving shift command information of an automatic transmission. A suspension means for a vehicle, characterized in that the compensation means is configured to increase the control gain during power mode traveling as compared with during econo mode traveling. . 2. A hydraulic cylinder installed between a vehicle body and wheels of a vehicle equipped with an automatic transmission, and controlling supply and discharge of a working fluid to and from the cylinder so as to suppress at least pitching of the vehicle body. In a vehicle suspension device provided with a controller, a vehicle speed detecting means for detecting a vehicle speed, receiving shift command information of an automatic transmission, and temporarily adjusting a control gain for suppressing pitching in synchronization with shift timing. Correction means for increasing the control gain when the vehicle speed is lower than the predetermined vehicle speed is greater than the control gain increase amount when the vehicle speed is higher than the predetermined vehicle speed. A suspension device for a vehicle, characterized in that the vehicle suspension device is configured to: 3. A hydraulic cylinder installed between a vehicle body and wheels of a vehicle equipped with an automatic transmission, and controlling supply and discharge of a working fluid to and from the cylinder so as to suppress at least pitching of the vehicle body. A suspension device for a vehicle comprising a controller and a correction means for receiving shift command information of the automatic transmission and temporarily increasing a control gain for controlling pitching in synchronization with a shift timing; The correction means calculates the increase amount of the control gain when the shift in the automatic transmission is a shift between a first shift speed and a second shift speed higher than the first shift speed. A configuration in which the shift is larger than an increase amount of the control gain at the time of a shift from the second shift speed to a third shift speed higher than the second shift speed. That has been Suspension apparatus for vehicles according to claim.