JPH055709B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an integrated control device for a suspension device and a steering device with variable characteristics.

A vehicle's suspension device has the role of supporting the weight of the vehicle and cushioning road surface irregularities, and it not only improves ride comfort but also prevents pitching, rolling, and
Furthermore, it has a significant effect on stability and responsiveness during turning. Therefore, by appropriately changing the suspension characteristics of the front and rear wheels of the vehicle, the dynamic characteristics can be varied in various ways. For example, in Utility Model Application Publication No. 55-109008, in order to improve responsiveness and stability in the transitional situation from straight running to cornering, the damping force of the shock absorber on the rear wheel side is applied to the front wheel side at high speeds. A control device has been disclosed in which understeer characteristics are obtained by relatively reducing the damping characteristics, and at low speeds, the relationship of damping is reversed between the front and rear wheels to obtain neutral steering or oversteer characteristics. In addition, Utility Model Application No. 56-147107 detects roll speed using a steering sensor that detects changes in steering angle and a vehicle speed sensor, and controls the roll speed by increasing (hardening) the damping force of the shock absorber. A device has been disclosed which improves both maneuverability and ride comfort by preventing the vehicle from exceeding a predetermined level.

On the other hand, power steering devices have become widely used as steering devices for steering vehicles, especially from the viewpoint of ease of steering. Due to this significant impact, various improvements have been proposed in the past. For example, Japanese Patent Application Laid-Open No. 55-55059 discloses that the number of revolutions of an oil pump that supplies hydraulic pressure to a hydraulically operated power steering device is controlled according to changes in vehicle speed, the axle load of the steered wheels, or steering resistance. A control device has been proposed that stabilizes steering by supplying pressurized oil.

These conventional devices have individually improved the suspension device or steering device,
Although this method has achieved a certain degree of effectiveness, there are limits to its effectiveness when these suspension devices and steering devices are individually controlled. In particular, there are individual differences in driver preferences regarding vehicle dynamic characteristics such as steering response and ride comfort, which vary widely from person to person, so these conventional methods do not always meet the driver's needs. It wasn't something.

Therefore, an object of the present invention is to comprehensively control a suspension device and a steering device with variable characteristics to provide appropriate steering response and control according to the driver's preference.
The object of the present invention is to provide a control device for a suspension device and a steering device that can provide stability, ride comfort, etc.

The object of the present invention is to provide a suspension device for each wheel, a steering device for steering a steerable wheel among the wheels, a first control means for changing suspension characteristics of the suspension device, and a steering device for controlling a suspension device for each wheel. a second control means for changing a transmission characteristic between a steering wheel and a steering wheel; and a first control signal for changing a suspension characteristic of the suspension device to be outputted to the first control means; A second control signal that changes the transfer characteristic of the steering device according to the output is transmitted to the second control signal.
a controller that outputs an output to a control means, the controller being configured to change the transmission characteristics of the steering device at the same time as the suspension characteristics of the suspension device change. This can be achieved by equipment.

According to the present invention, since the controller is provided to control the suspension characteristics of the suspension device and the steering characteristics of the steering device to be changed at the same time, the dynamic characteristics of the vehicle can be adjusted according to the driver's preference. It becomes possible to change it over a wide range. For example, if the suspension device has a large spring constant or has a relatively strong damping force, increasing the assist force of the power steering device will create a sporty feeling that responds sensitively to steering operations. is obtained.
On the other hand, if the suspension characteristics are changed so that the spring constant of the suspension device becomes smaller or the damping force is weakened, and the assist force of the power steering device is controlled to be weakened accordingly, the vehicle will be relatively stable. It gives you a gentle feeling. When using a manual steering system, a sporty feeling can be obtained by reducing the steering gear ratio for hard suspension characteristics and improving steering sharpness, and increasing the steering gear ratio for soft suspension characteristics. If you turn the steering relatively gently, you can get a gentle feeling. Other combinations include weakening the assist force of the power steering device for hard suspension characteristics, or increasing the steering gear ratio and increasing the assist force of the power steering device for soft suspension characteristics. Alternatively, the steering gear ratio may be reduced. In this case, the change in the vehicle dynamic characteristics due to the switching of the characteristics does not appear too drastically, so it is suitable for cases where it is desired to change the dynamic characteristics in a relatively small range.

Furthermore, by performing different controls for the front wheels and rear wheels without changing the suspension characteristics for all wheels in the same way, it is possible to change the transmission characteristics between the steering wheel and the steered wheels of the vehicle. for example,
By increasing the damping force of the damper of the front wheel suspension system, or by decreasing the volume of the gas chamber of the gas spring system to increase the spring constant, and by reversing the suspension characteristics of the rear wheel suspension system, the tendency to understeer can be suppressed. It can be strengthened. In this way, the understeer tendency is strengthened or weakened by changing the suspension characteristics,
By changing the transmission characteristics between the steering wheel of the steering device and the steering wheels accordingly, it is possible to change the dynamic characteristics of the vehicle. For example, for suspension characteristics that tend to have a strong tendency to understeer, by reducing the assist force of the power steering device or increasing the gear ratio of the manual steering device, it is possible to obtain characteristics with relatively dull steering sharpness, thereby reducing the tendency to understeer. For relatively small suspension characteristics, a sharp steering sensation can be obtained by increasing the assist force of the power steering device or decreasing the gear ratio of the manual steering device.

Although the characteristic control according to the present invention may be selectively performed by a manual switch, it is also possible to perform automatic switching depending on the driving conditions of the vehicle.

For example, a gas spring device is used in the suspension device, and a control gas chamber is connected to the gas chamber of the gas spring device via a solenoid valve, and the effective volume of the gas chamber is changed by opening and closing the solenoid valve to control the gas spring. All you have to do is change the characteristics of In addition, an oleo damper provided with a piston variable diameter orifice may be used, and a means for varying the volume of the gas chamber of the gas spring and a means for varying the piston orifice diameter of the oleo damper may be combined. Furthermore, any means may be used as long as the suspension characteristics can be varied between hard and soft. In the case of a power steering system, the means for varying the characteristics of the steering device may be of a known type that changes the power assist force, for example, a method that changes the rotation speed of the hydraulic pump of the power steering system. , or a method of changing the amount of bypass of pressure oil. In the case of manual steering, a gear ratio switching mechanism that changes the steering gear ratio may be provided. In any case, by employing such means, it is possible to change the transmission characteristics between the steering wheel and the steered wheels by making the operating force of the steering device lighter or heavier.

Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIGS. 1 and 2, the handle 10
is connected via a steering shaft 12 to a pinion shaft 16 having a steering pinion 14 . The pinion 14 meshes with a rack 20 on the steering rack shaft 18.
8 moves left and right according to the rotation of the pinion 14, and connects the front wheels 26, 28 via the knuckle arms 22, 24.
The steering force is transmitted to the In order to assist this steering force, a hydraulically operated power assist device 30 is provided, and this device has a control valve 31 provided on the pinion shaft 16 and a power cylinder 32 on the rack shaft 18. cylinder 32
An oil pump 36 connected to the engine 34 is provided to supply hydraulic pressure to the engine 34. Pressure oil from the pump 36 is introduced into the control valve 31 through a hydraulic pressure supply passage 38, is switched by the valve 31 according to the operation of the handle 10, and is supplied to the power cylinder 3 via a hydraulic passage 40 or 42.
The piston 32
Move a to assist the steering force. At this time, the hydraulic passage to which pressure oil is not supplied is the hydraulic return passage 4.
4 to pump the hydraulic oil in the cylinder 32
Return to. The hydraulic pressure return passage 44 is provided with a solenoid valve 46 that adjusts the amount of oil returned to the pump 36 through the passage 44, and the hydraulic supply passage 38 is provided with a bypass passage 49 that communicates with the solenoid valve 46. The solenoid 46a of the valve 46 is connected to a controller 50, which receives power from a power source 51, and operates a vehicle speed sensor 52 and a manual switch 54.
Solenoid valve 46 receives the signal from
send a control signal to. Plunger 46 of valve 46
b is displaced by an amount corresponding to the current or electric power from the controller 50, thereby changing the flow rate in the passage 38 and controlling the hydraulic pressure in the cylinder 32, that is, the assist force. front wheel 2
A suspension device 60 is provided in association with the rear wheels 6 and 28 and the rear wheels 56 and 58. This suspension device includes a shock absorber 66 consisting of a spring 62 and an oleo damper 64, and an air spring 68 is formed around the damper 64 by a diaphragm made of a suitable elastic material. The orifice provided in the piston of the shock absorber 66 has a variable diameter, and in order to change the diameter, a plunger driven by a solenoid 69 is provided in the piston rod 67. When the solenoid 69 is energized, the plunger is driven by a solenoid 69. It is configured to rotate to reduce the diameter of the orifice and increase the damping force to harden the suspension characteristics of the suspension device. Further, the air spring 68 is connected to a control air chamber 72 through an air pipe 70, and the air spring 68 and the control chamber 72 are connected to each other by actuation of a solenoid valve 74 provided at the entrance of this chamber 72.
The communication state with is controlled. In this example, when the solenoid 74a of the solenoid valve 74 is energized, communication is cut off. Air spring 68 and control room 7
2, the effective volume of the air chamber decreases, the spring constant of the air spring increases, and the suspension characteristics of the suspension device become hard. Thus, the suspension characteristics of the suspension system can be controlled by operating the solenoids 69, 74a in response to signals from the controller 50.

As described above, the controller 50 receives the vehicle speed signal as an input, and the control signal given from the controller 50 to the solenoid valve 46 changes depending on the vehicle speed. That is, the solenoid valve 46 is controlled so that the amount of pressure oil supplied from the pump 36 to the control valve 31 decreases as the vehicle speed increases. When the manual switch 54 is operated, the solenoid valve 4 is activated from the controller 50.
The level of the signal applied to valve 6 is lowered, the opening degree of valve 46 is reduced, and the assist force is strengthened as a whole. At the same time, a signal is given from the controller 50 to the solenoids 69, 74a of the suspension device, and the characteristics of the front and rear wheel suspension devices become hard.

3 and 4 show an embodiment of the invention using a manual steering system.
In the device of this example, the steering device includes a gear mechanism 80 with a variable gear ratio so that the transmission characteristics between the steering wheel and the steered wheels can be changed. This gear mechanism 80 is provided in the middle of the steering shaft 12, and controls the gear ratio between the shaft portion on the handle 10 side, that is, the input shaft 12a, and the shaft portion on the pinion shaft side, that is, the output shaft 12b, based on a signal from the controller 50. It is designed so that it can be changed depending on the A gear 82 is formed integrally with the input shaft 12a, and the gear 82 meshes with a gear 84. The gear 84 is housed in a gear casing 90 that supports these shafts 12a and 12b via a bearing device 86 attached to the input shaft 12a and a bearing device 88 attached to the output shaft 12b. It is rotatably attached to a countershaft 92 that is attached substantially parallel to the output shaft. A gear 94 having a smaller number of teeth than the gear 84 is provided integrally with the gear 84.
4 meshes with a gear 96 rotatably attached to the output shaft 12b. Input shaft 12a and output shaft 12b
A gear 98 is formed on the input shaft 12a, a gear 100 is formed on the output shaft, and a gear 102 is provided adjacent to the gear 100 and integrally with the gear 96. These gears 98,
100 and 102 have coupling sleeves 104
engages with the spline. A shift fork 106 is engaged with the sleeve 104 for moving the sleeve. Shift fork 106 supports casing 10 on bearing devices 86 and 88.
It is attached to a plunger 112 operated by a solenoid 110 housed in 8. The solenoid 110 is energized or demagnetized by a signal from the controller 50, and when the solenoid 110 is not energized, the plunger 112 is activated by the spring 11.
4, it is pressed to the lower position in FIG. At this time, the sleeve 104 is engaged with both the gear 100 of the output shaft 12b and the gear 102 integrated with the gear 96,
rotates together with the gear 96. Therefore,
The steering force of the handle 10 that rotates the input shaft 12b is transmitted in the order of gear 82, gear 84, gear 94, and gear 96, and rotates the output shaft. In this case, the ratio of the steering angle of the output shaft to the input shaft (gear ratio) is large, and the steering force of the handle 10 is relatively small. When the solenoid 110 is energized and the plunger 112 is pulled upward against the force of the spring 114, the shift fork 106 moves upward together with the sleeve 104, and the sleeve 104 connects the gear 100 of the output shaft and the gear 96. Gear 10 integrated with
2 and engages both the gear 98 of the input shaft 12a and the gear 100 of the output shaft 12b.
Thereby, the input and output shafts 12a and 12b are directly connected, and the steering force that rotates the input shaft is directly transmitted to the output shaft 12b. In this case, the above-mentioned gear ratio is small, and at the same time the responsiveness of the steering becomes high, a relatively large steering force is required. The inputs to controller 50 and suspension equipment in this example are the same as in the previous example. Therefore, the driver can operate the manual switch 54 to simultaneously change the suspension characteristics and the transmission characteristics between the steering wheel and the steering wheel, thereby obtaining the desired motion characteristics.

Referring to FIGS. 5 and 6, yet another embodiment is shown. In the suspension device of this example, only the suspension characteristics of the rear wheels can be changed. By operating the manual switch 54, the driver can change the suspension characteristics of the rear wheel suspension device 60 to hard or soft. If the suspension characteristics of the rear wheels are made relatively hard compared to the suspension characteristics of the front wheels, the understeer tendency of the vehicle will be weakened, and conversely, if the suspension characteristics of the rear wheels are made relatively soft, the understeer tendency will be strengthened. Therefore, by operating the manual switch, the driver can adjust the transmission characteristics and suspension characteristics between the steering wheel and the steering wheels.
In particular, you can obtain understeer characteristics according to your preference.

The above-mentioned examples illustrate specific combinations of steering characteristics and suspension characteristics of the suspension system, and combinations according to the invention include any other combinations.

7 to 10 show some of the dynamic characteristics for a particular combination of steering characteristics and suspension characteristics of the suspension device according to the invention, when the vehicle speed is held approximately constant.

FIG. 7 shows the relationship between the steering force of the steering wheel 10 and the yaw rate. Lines a and b are the characteristics when a manual steering device is used, and line a is when the all-wheel suspension characteristics of the suspension device are soft, i.e., The damping force is small, and line b indicates the case where the all-wheel suspension characteristics are controlled to be hard. In this case, the steering force and yaw rate are almost directly proportional, and the yaw rate is larger when the suspension characteristic is harder for the same steering force. Lines c and d are when a power steering device is used and the assist force is controlled to be low; line c shows soft all-wheel suspension characteristics, and line d shows hard all-wheel suspension characteristics. This shows what was controlled in this way. In this case as well, the steering force increases as the yaw rate increases, but this tendency is slower than in lines a and b. This is because the assist force of the power steering device is acting. In general, the control valve of a power steering device is a torque-sensitive type, and assist force begins to be generated when the steering force exceeds the point indicated by A or B, which increases the amount of pressure oil supplied to the power cylinder as the steering resistance increases. . Regarding lines c and d, if the yaw rate is the same, a softer all-wheel suspension characteristic requires a larger steering force. Lines e and f are the cases where the power steering device was similarly used and the assist force was controlled to be large; line e was controlled so that the all-wheel suspension characteristics were soft, and line f was controlled so that the suspension characteristics were hard. This is the case. The trends of lines e and f are the same as those of lines c and d, but since the assist force is large, the overall steering force is small. Even in this case, the driver can obtain an appropriate steering feeling. The assist force is cut below points C and D. By arbitrarily combining the suspension characteristics of the suspension with the transmission characteristics between the steering wheel and the steering wheels of the power steering, it is possible to obtain a steering feeling that matches the driver's preference.
In the embodiment shown in FIGS. 1 and 2, c and f are selected as the transmission characteristics between the steering wheel and the steering wheel, and the switching between them is performed in accordance with the switching between hard and soft suspension characteristics. FIG. 8 shows the relationship between the steering angle of the steering wheel and the yaw rate when a manual steering device is used. Lines a and b represent the case where the input shaft 12a of the steering shaft 12 and the output shaft 12b are not directly connected, but the steering force is controlled to be transmitted to the output shaft 12b via a predetermined gear mechanism. In this case, the ratio of the steering angle of the input shaft to the steering angle of the output shaft 12b, that is, the gear ratio, is large, and the steering wheel steering force is relatively small. Line a shows soft all-wheel suspension characteristics, and line b shows soft all-wheel suspension characteristics.
This is the case when the all-wheel suspension characteristics are tightly controlled.
On the other hand, lines c and d represent the case where the input shaft 12a and output shaft 12b are directly connected, that is, when the gear ratio is reduced, and line c shows the case where the all-wheel suspension characteristics are soft.
Line d shows the case where the all-wheel suspension characteristics are hard controlled. In either case, the steering angle and yaw rate are almost directly proportional. Furthermore, when the steering wheel steering angle is the same, the smaller the gear ratio, that is, the direct connection state, the larger the yaw rate, and the harder the suspension characteristics of the suspension device, the larger the yaw rate. By arbitrarily combining the suspension characteristics of the suspension and the steering characteristics of the manual steering, it is possible to obtain a steering feeling that matches the driver's preference. In other words, the transmission characteristics a, b or c, d between the steering wheel and the steering wheel
The selection is made according to the change in suspension characteristics between hard and soft.

FIG. 9 shows the relationship between steering wheel force and centripetal acceleration.

Lines a and b use a manual steering device, line a shows large understeer characteristics, that is, the rear wheel suspension characteristics are controlled to be soft compared to the front wheel suspension characteristics, and line b shows small understeer characteristics, that is, the front wheels are controlled so that the rear wheel suspension characteristics are soft. This is a case where the rear wheel suspension characteristics are controlled to be hard.

In this case, the steering wheel steering angle and the centripetal acceleration are in a substantially directly proportional relationship, and the steering wheel steering force that produces the same centripetal acceleration is smaller when the understeer characteristic is reduced. Lines c and d show the case where the power steering device is used to control the assist force to a low level; line c shows the understeer characteristic is large, and line d shows the case where the understeer characteristic is controlled to be small. Lines e and f show the case where the power steering device is used to control the assist force so that it becomes relatively large, line e shows the case where the understeer characteristic is large, and line f shows the case where the understeer characteristic is controlled so that it is small. . These lines c, d, e,
f shows the same tendency as lines c, d, e, and f in FIG. 7, and the greater the understeer characteristic, the greater the need for a greater steering force. In this case as well, the assist force is cut off in a range where the steering force is small in order to give the driver an appropriate steering sensation. By arbitrarily combining the suspension characteristics of the suspension and the steering characteristics of the power steering, it is possible to obtain a steering feeling that matches the driver's preference. In other words, the transmission characteristics c, f or e, d between the steering wheel and the steering wheel are selected, and the selection is made in accordance with the change in strength of the understeer characteristic.

FIG. 10 shows the relationship between the steering angle of the steering wheel and the centripetal acceleration when a manual steering device is used. Lines a and b show the case where the aforementioned gear ratio is increased, and line a shows the control so that the understeer characteristic is large, and line b shows the case where the understeer characteristic is controlled to be small. Lines c and d are for the case where the gear ratio is small, that is, in a direct connection state, and
Line c shows the control so that the understeer characteristic is large, and line d shows the control so that the understeer characteristic becomes small. The steering wheel steering angle and centripetal acceleration are almost directly proportional in the range where the steering angle is small.
When the steering angle increases beyond a certain point, the centripetal acceleration does not change that much even if the steering angle changes. The larger the gear ratio and the larger the understeer characteristic, the smaller the centripetal acceleration caused by the same steering angle.

As described above, the dynamic characteristics of the vehicle vary depending on changes in the suspension characteristics of the suspension device and the transmission characteristics between the steering wheel and the steering wheels.
By operating the manual switch, the driver can obtain the driving characteristics according to his/her preference.
By arbitrarily combining the suspension characteristics of the suspension and the steering characteristics of the manual steering, it is possible to obtain a steering feeling that matches the driver's preference. In other words, the transmission characteristics a, b or c, d between the steering wheel and the steering wheel
is selected, and the switching is performed according to the switching of the strength of the understeer characteristic.

[Brief explanation of drawings]

FIG. 1 is an overall perspective view of a suspension device and a steering device according to one embodiment of the present invention, FIG. 2 is a control circuit diagram of the embodiment of FIG. 1, and FIG. 3 is another embodiment of the present invention. FIG. 4 is a diagram similar to FIG. 2 of the embodiment shown in FIG. 3, FIG. 5 is a diagram similar to FIG. 1 of another embodiment, and FIG. 6 is a diagram similar to FIG. teeth,
A diagram similar to FIG. 2 of the embodiment of FIG. 5, FIG.
Figure 8 is a graph showing the relationship between steering force and yaw rate. Figure 9 is a graph showing the relationship between steering angle and yaw rate.
The figure is a graph showing the relationship between steering force and centripetal acceleration.
FIG. 10 is a graph showing the relationship between steering angle and centripetal acceleration. Explanation of symbols, 10...Handle, 18...Rack shaft, 30...Power assist device, 36...Oil pump, 50...Controller, 54...Manual switch, 60...Suspension device, 66
...Shock absorber, 72...Controlled air chamber,
80...Gear mechanism.

Claims (1)

[Claims] 1 A suspension device for each wheel, a steering device for steering a steerable wheel among the wheels, a first control means for changing suspension characteristics of the suspension device, a steering handle of the steering device, and a steering wheel. a second control means for changing a transmission characteristic between the suspension devices; and a first control signal for changing a suspension characteristic of the suspension device to the first control means, and a steering device according to the output of the first control signal. a controller that outputs a second control signal for changing the transmission characteristic of the steering device to the second control means, the controller configured to change the transmission characteristic of the steering device simultaneously with a change in the suspension characteristic of the suspension device. A comprehensive control device for suspension and steering, characterized by the following: