JPS62125907A - Variable suspension geometry device - Google Patents

Abstract

PURPOSE:To improve reduction in steering force at the time of low speed and stability in straight advance at the time of high speed by varying the caster angle of a suspension in accordance with a vehicle speed when the neutral position of a steering wheel is detected by a sensor. CONSTITUTION:Each of the wheels 2 of a vehicle 1 is steered, with the caster of each suspension being independently varied by means of a signal from a control unit 4. In the wheel 2, upper links 11, 12 and lower links 13, 14 are installed on a knuckle 10 and the stroked of these links are adjusted by said unit 4 based on detected signals from stroke sensors 15-18. A vehicle speed sensor 6, a sensor 7 for detecting the steering angle, i.e., the neutral position of a steering wheel 5, and a sensor 67 for detecting steering angle, are provided on the vehicle 1. And, when the steering wheel 5 is in the neutral position, the caster angle of a suspension is varied in accordance with a vehicle speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable suspension geometry device, for example in an all-wheel steering system.

[Conventional technology]

Currently, the caster angle of the suspension in a vehicle steering system, that is, the inclination (angle) of the king pin center line when looking at the wheels of the vehicle from the side, is configured to be fixed. In general, regarding the caster angle, when the vehicle is running at low speed, a smaller caster angle reduces the steering force, and when the vehicle is running at high speed, a larger caster angle provides better straight-line stability, and when the vehicle is being steered, the caster angle is smaller. This allows for better turning performance. As described above, the ideal value of the caster angle varies depending on the driving condition of the vehicle.

Conventionally, a device that can automatically change the caster of a vehicle's suspension in the forward or reverse direction was disclosed in a patent application filed in 1986-15.
This method has already been disclosed in Japanese Patent No. 345. This caster automatic forward/reverse change device is constructed as follows. That is, a switch is provided that is operated by the end surface of the reverse three-pronged shaft of the transmission, and the switch is incorporated into the battery circuit containing the electric motor, and a pump is directly connected to the electric motor, and the pump generates hydraulic pressure. Activate the piston. The piston is provided with a return spring. Pull your arm downward through the joint and ball in the middle of the piston. The shaft fixed to the arm therefore slides in the bearing of the front axle eye beam. The shaft is L-shaped and is attached to a caster shaft, and the caster shaft is tilted in the opposite direction. When the two-pronged shaft returns to its original position, the switch circuit is opened and the electric motor and pump stop operating, and the spring operates to return the caster shaft to its original position.

[Problem that the invention seeks to solve]

However, as mentioned above, the caster axle is fixed, and the ideal value differs depending on the condition of the vehicle, but as mentioned above, the caster axle is fixed, and the caster is at a compromised angle. ing. Therefore, the steering force,
The problem is that straight-line performance and maneuverability are compromised, and the caster angles are not ideal depending on the driving conditions of the vehicle. In addition, the above patent application 1986-1
What is disclosed in Japanese Patent No. 5345 is that the caster angle is set to a predetermined value in forward and backward travel, and only S is used.
The inclination direction is simply changed to the opposite direction, and the caster angle cannot be adjusted continuously, which has the same problem as above.

The purpose of this invention is to solve the above problems,
For example, it is possible to change the caster angle according to the vehicle's driving condition without changing the wheel tread and camber, dramatically improving the vehicle's straight-line stability and handling performance, and reducing the steering force. An object of the present invention is to provide a variable suspension geometry device in a wheel steering system.

[Means for solving problems]

In order to solve the above problems and achieve the above objects, the present invention is configured as follows.

That is, the present invention relates to a variable suspension geometry device that is provided with a sensor that detects the state of the steering wheel, and adjusts the caster angle of the suspension according to the vehicle speed based on a signal from the sensor. In other words, it is a neutral position sensor that detects the position of the steering wheel when the vehicle is running straight, and changes the caster angle according to the vehicle speed at the neutral position, and decreases the caster angle when the vehicle is at a position other than the neutral position. The present invention relates to a variable suspension geometry 'A'll, wherein the caster angle of the wheels is adjusted by control from a control unit, and the sensor is a steering angular velocity sensor that senses the rotational angular velocity of the steering wheel.

[Effect]

This invention is configured as described above and operates as follows. The caster of the vehicle's suspension can be adjusted by adjusting whether the suspension wheels are in the neutral position, so when the vehicle is running at low speeds, the caster angle can be reduced to lighten the steering force, and when the vehicle is running at high speeds, the caster angle can be increased to make it easier to drive straight. Stability can be improved, and the caster angle can be reduced during steering to obtain good turning performance. Furthermore, the caster angle can be adjusted according to the steering angular velocity of the steering wheel, so that the caster angle can be reduced to improve turning performance at the beginning or end of a turn to reduce directional stability, and during a constant turn. In order to obtain the return force of the steering wheel, the caster angle can be increased to improve turning stability and provide a favorable feeling.

〔Example〕

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

As for the variable suspension geometry device according to the invention, its variable means are illustrated in principle in FIG. Wheel 2 (or 3) due to rotation of axle 8
Assume that the vehicle is running on the road surface 9. The connection point where the left and right upper links are connected to the knuckle is indicated by 21, and the connection point where the left and right lower links are connected to the knuckle is indicated by 22. If the connecting points 21 and 22 move in the direction of arrow X, the caster angle α increases, and the connecting points 21 and 22 move in the direction of arrow Y.
．． If 22 moves, the caster angle α decreases.

In Fig. 2 (a), when the vehicle l runs around a corner, the road surface 9 is divided into sections A, B, and C according to the steering angular velocity.
, D, and E are shown.

In FIG. 2(b), a graph schematically shows how the steering angular velocity γ and caster angle α in sections A, B, C, D, and E change over time T.

In FIG. 3, a variable suspension geometry arrangement in a vehicle 1 is schematically shown.

The vehicle 1 has front wheels 2.2 and rear wheels 3.3, and each axle 2.3 is steered by independently changing the caster of the suspension in response to signals from the control unit 4. Each wheel 2.3 has a respective knuckle 10, to which an upper link 11.12 and a lower link 13.14 are attached. The strokes or lengths of these upper links 11.12 and lower links 13.14 are adjusted by signals from the control unit 4, and each link has an upper link 11.12 for detecting the strokes. A stroke sensor 15.16 and a stroke sensor 17.18 of the lower link 13.14 are provided. The vehicle 1 is provided with a vehicle speed sensor 6 that detects the speed of the vehicle l. Further, a neutral position sensor 7 that detects the steering angle of the steering wheel 5, that is, a neutral position, and a steering angular velocity sensor 67 that detects the steering angular velocity are provided. In the figure,
Reference numeral 19 indicates an acceleration sensor in the left-right direction, and reference numeral 20 indicates an acceleration sensor in the longitudinal direction.

As is clear from FIGS. 1 and 3, when moving the connection point in the X direction, it is sufficient to shorten one of the lower links 13 or 14 and lengthen the other. This is achieved by lengthening either 11 or 12 and shortening the other. Also, Y
If the connection point is to be moved in this direction, this is achieved by adjusting the lower link 13.14 and the upper link 11.12 in the opposite direction.

Referring to the flowchart of FIG. 10, a case will be described in which the variable suspension geometry device according to the present invention detects the signal of the neutral position of the steering wheel 5 and adjusts the caster angle according to the vehicle speed.

By turning on the main key and then turning it on, the neutral position of the steering wheel 5 is detected and determined by the neutral position sensor 7.
−・−・−−−−−−−−−−−・−・−・−・・−
(50) When the steering wheel 5 is in the neutral position, the vehicle speed V is detected by the vehicle speed sensor 6.

−・−・−−−１−・−−１−−〜−
(51) When the vehicle speed V is detected, the caster angle α is processed. α=A
V, α=α, +AV, αzBV! , α=α. +BV”
−・・−・−11′−”−−−−・・・・(52) Once the caster angle α is determined, the length of each suspension arm, that is, the upper link, is adjusted to the caster angle α. 11.12 and the length l of the lower link 13.14 can be calculated.

−・−・−・−−−−−−・−−−−−−−−−−−−
----(53) Changing the length of the upper link 1112 and lower link 13.14 by hydraulic or electric power,
Adjust to a predetermined caster angle α. −−−−−−−1−−
...(54) Stroke sensor 15.16.17.
18 detects the length l of the upper link 11.12 and the lower link 13.14. −−−−−−−−
(55) Actual length of upper link 11.12 and lower link 13.14 and calculated upper link 11
．． 12 and the length l of the lower link 13 and 14. If the difference is IA-zcl=o, the process is ■
Move to. If the difference 1β-11>0, it is fed back to the above (54).

−−−−−−−−−−−−−−−−−−−−−・−・
... (56) In (50) above, if it is determined that the steering wheel 5 is not in the neutral position,
The process proceeds to (57).

When the caster angle α is [αl=o, the response is improved and the turning performance is good. If 1α1〉0,
The process proceeds to (58), -・〜・・・−・−・(57
) The caster angle α is processed to be 1/2.1/3.1/4 of the value of the caster angle α processed in (52) above, and in this case, the steering system during turning It is processed so as to leave a force to return the vehicle to a straight-ahead state.

−−−1−−−−・−・・−−−−−−−−−−−−
(5B) Once the caster angle α is determined, the corresponding arm length EC of each suspension is calculated.・・・－・・−・−
・−−−−−−−−−−−−−−−−−−−1−−−
--- (59) To change the length of the arm, the upper link 1112 and lower link 13.14 are adjusted. −・・・・・・・−−−−−・・
・−−−−−−−・−m−−−・−−−−1−・(60
) The actual length l of the arm length is detected by the stroke sensor 15.16.17.18.

−−−−11−−−−・・−−〜−−−−−−−−−
------- (61) Determine the difference between the actual arm length 2 and the calculated arm length pc. That is, if l z−xel >Q, then (60)
If l p-xcl =o, the process moves to (2). −・・−・・−−−−−−−1−−−−−−−−−−・−m−−−−−−−(62)
Next, with reference to the flowchart of FIG. 11, a case will be described in which the variable suspension geometry device according to the present invention adjusts the caster angle in accordance with the vehicle speed by receiving the signal of the steering angular velocity of the steering wheel.

By inserting the main key to start and then turning it on, the steering angular velocity γ of the steering wheel 5 is detected and determined by the steering angular velocity sensor of the steering wheel 5. That is, the magnitude of the predetermined steering angular velocity r0 and the actual steering angular velocity T is determined, and if γ-ro, the process proceeds to step (71), and if T≧r0, the process proceeds to step (77).

−・−・−・−−−−−−−−−−−−−−−−−−−
-・------(70) Vehicle speed V is detected by the vehicle speed sensor.

−−−1−−−−−−−−−−−−−−−−−−−−
・−m−−−−・−(71) When vehicle speed ■ is detected,
The caster angle α is processed. Increase the caster angle α according to the vehicle speed ■.

That is, α=A・■, α=α. +A・■, α=B V
”, α=B −V ” −−−−,−−−−−
--(72) Once the caster angle α is processed, the length l of each suspension arm is calculated.

−・・−１−−−−−−−−−−−−−−−・−・・
(73) Upper link 11.12 and lower link 13.1 in order to make the length of each suspension arm equal to the arm length β.
The length of 4 is adjusted. −−−−−−−−−1−
(74) The actual arm length l is detected by the stroke sensor.

−・・・・・−・−−−−−m−−−−−・・−−−
−1−・−(75) Actual arm length l and calculated arm length ρ. The difference between the two is determined. 12-1゜l
If =o, the process moves to ■, and 11-βcl>0
If so, it is fed back to the above (74).

−・−・・−・・−−−−−−：−１−−−・−・−−
-----・-(76) In the above (70), γ≧“.

If so, it is determined that 1α1=0 or 1α1>0. If α=07, the directional stability will be good, but the turning performance will not improve. If 1α1>0, 1/2.1/3.1/ of the value of caster angle α processed in (72) above.
4-...The caster angle α is processed,
In this case, the steering system is processed so as to maintain a force for returning the steering system to the straight-ahead state during the turn. −−−−−m−・−−−
--- (78) Once the caster angle α is determined, the suspension arm length pc corresponding to the caster angle α is calculated. −1−−−・・・−・−−−−−−
−−１−・−−−１−−−−−−・・−・−・−・(7
9) The length of the upper link 11.12 and the lower link 13.14 is adjusted to change the length of the arm so that it becomes the calculated arm length l.
−・−・−・・−・−・・・・・−・−−−−−
------m---(80) Stroke sensor 15.
The actual length e of the arm is determined by 16.17.18.

−・・−−−−−−−1−−−−−−−−−・−・−
(81) The difference between the actual arm length l and the calculated arm length 12c is determined.
That is, 1ff-/! , if l=o, the process moves to ■, and if 1g-xel>o, the above (8
The feed is sent to 0).・−・−−1−−−−・
−−−−−−−−−−−−−−−−−・−・(82)
In FIG. 4, an example of an adjustment device for changing the length of a suspension arm is shown. This adjustment device adjusts only the length of the lower link 13, 14 using hydraulic pressure. One end of an upper link 11.12 and a lower link 13.14 are connected to the knuckle 10 attached to the wheel 2.3. lower link 13
．． 14 are connected at one end. Lower link 13.1
A piston 30 is attached to the other end of 4, and the piston 30 slides within the cylinder 29. In the cylinder 29,
Oil from the oil tank 24 is pumped through the check valve 26 by the pump 25.
, the cylinder 29 through the switching valve 23 and one control valve 28.
is sent to one of the chambers. The oil in the other chamber of the cylinder 29 passes through the other control valve 28 and the switching valve 23 to the oil tank 29.
Returned to 4. This hydraulic pressure causes the piston 30 to slide, moving the lower link 13.14, changing the stroke, moving the knuckle IO, and adjusting the caster angle of the wheel 2.3. The length of the stroke at this time, ie, the length of the lower link 13.14, is detected by the stroke sensor 17.18.

The adjustment device for adjusting the length of the upper links 11, 12 is the same as the adjustment device described above, so a description thereof will be omitted.

In FIG. 5, another example of an adjustment device for changing the length of a suspension arm is shown.

This adjustment device adjusts only the length of the lower link 13, 14 using a screw. Only the lower links 13, 14, as well as those with the hydraulic adjustment device described above, will be described. Knuckle 10 and lower link 13.14
One end of the lower link 13, 14 is connected, and a female thread 36 is formed at the other end of the lower link 13,14. The zero-rotation shaft 33, in which a rotary shaft 33 having a male thread 35 is screwed into the female thread 36, is attached to the podium 31 via a bearing 34, and is rotationally controlled by a motor. A stroke sensor 17.18 is provided for the lower link 13.14. The rotating shaft 33 is rotated by the rotation of the motor 32.
rotates, the stroke of the lower link 13.14 is changed, the knuckle 10 moves, and the caster angle of the wheel 2.3 can be adjusted by y4.

Stroke sensors 17 and 18 include those that use permanent magnets to detect the stroke length based on the position of the magnet, or those that convert resistance values into strokes. It can be anything, and it is not limited.

In FIG. 6, an example of the neutral position sensor 7 of the steering wheel 5 is shown. The shaft 38 of the steering wheel 5 is linked to a pulley 39 that is decelerated by the shaft 38 by a belt, chain 37, or the like. The pulley 39 is provided with a contact 40 formed as a protrusion, and is configured to be able to contact a contact 41 in a circuit supported by a spring. In the figure, 42 is an indicator lamp, and 43 is an output signal from a sensor. The contact 40 of the pulley 39 and the contact 41 of the circuit are configured so that the contact 40 of the pulley 39 and the contact 41 of the circuit are always brought into contact when the steering wheel 5 rotates more than one revolution, for example, at least about two revolutions, and the point of contact is connected to the steering wheel 5. Set to neutral position.

Since the neutral position sensor 7 is configured in this way,
It works as follows. That is, when the contacts 40 and 41 are in contact, the switch is turned on, the indicator lamp 42 lights up, the voltage value is sensed, an output signal 43 is generated from the sensor output terminal, and the signal is sent to the control unit 4. . When the steering wheel 5 is in a position other than the neutral position, the contacts 40 and 41 do not come into contact with each other, and the switch is turned off. Therefore, the neutral position sensor 7 does not sense any voltage value and no output signal is sent to the control unit 4.

In FIG. 7, another example of the neutral position sensor 7 of the steering wheel 5 is shown. This neutral position sensor 7 is provided on the rack and pinion of the steering device. The pinion 44 at 9F of the handle shaft 65 is engaged with the rack 45, and the rack 45 is integrally formed with the rack shaft 46. rack shaft 4
A contact 47, which is a protrusion, is formed at 6, and a contact 48 in the circuit that protrudes inward from the outer case 64 of the rack 45 is attached to the outer case 64. The contact point 47 and the contact point 48 are configured to be able to come into contact with each other as the rack shaft 46 moves, and the contact position is set to be the neutral position of the steering wheel 5.

Reference numeral 49 in the circuit indicates an indicator lamp, and reference numeral 63 indicates an output signal 63 of the neutral position sensor 7. The neutral position sensor 7 is constructed in this manner, and its operation is similar to that shown in FIG. 6.

In FIG. 8(a), an example of the steering angular velocity sensor 67 is shown. This steering angular velocity sensor 67 is attached to the column shaft 66 of the steering wheel 5. In FIG. 8(b), the steering angular velocity sensor 6
A schematic structure of 7 is shown. A core 83 around which a coil 68 is wound is installed on the outer periphery of the column shaft 66 of the steering wheel 5, and a permanent magnet 69 is arranged on the outer periphery of the core 83. Therefore, column shaft 66
This means that an alternating current generator including a coil 68 and a permanent magnet 69 is attached to the coil 68 and the permanent magnet 69. The current flowing through the coil 68 is taken out as an output signal 84. Since the steering angular velocity sensor 67 is configured as described above, it functions as follows. The steering wheel 5 is rotated by the column shaft 6
6 rotation, and the rotational angular velocity of the column shaft 66 can be converted into the frequency of the current of the alternator and sensed. Therefore, the steering angular velocity of the steering wheel 5 can be detected as the output signal 84. Its output signal 84 is sent to the control unit 4.

In FIG. 9, another example of the steering angular velocity sensor 67 is shown. This steering angular velocity sensor 67 is attached to the column shaft 66 of the steering wheel 5. This steering angular velocity sensor 67 has an optical grating 89 fixed to the column shaft 66, and a light emitter 86 and a light receiver 85 are installed with the optical grating 89 in between. A slit 87 is formed in the optical grating 89.

The steering angular velocity sensor 67 configured in this manner operates as follows. The rotation of the steering wheel 5 causes the column shaft 66 to rotate, and the rotation of the column shaft 66 causes the optical grating 89 to rotate. Therefore, the angular velocity of the steering wheel 5 becomes the angular velocity of the optical grating 89, which means that the optical signal from the emitter 86 is converted into the frequency of a waveform signal by the receiver 85 and taken out, and the output signal 8
8 and sent to the control unit 4.

The above two steps are required to detect the angular velocity of the steering wheel.
Although two examples have been described, the invention is not limited to these examples. For example, in order to improve response, each of the above examples can be enhanced with gears, chains, etc. and positioned on the shaft. .

〔Effect of the invention〕

Since the variable suspension geometry 'AM according to the present invention is configured as described above, it detects whether the suspension wheel is in the neutral position, that is, the steering wheel is not rotated because the vehicle is traveling straight, and adjusts the vehicle speed. The caster angle of the suspension can be changed and adjusted accordingly, and the rotational angular velocity of the steering wheel can be sensed to change and adjust the caster angle of the suspension according to the vehicle speed.

Therefore, by detecting the neutral position of the steering wheel, the caster angle is reduced to reduce the steering force when the vehicle is at low speed, and the caster angle is increased when the vehicle is at high speed to improve straight-line stability. Furthermore, during steering, that is, when the steering wheel is at a position other than the neutral position, the caster angle can be reduced to improve turning performance. Therefore, it is possible to improve the high-speed straight running stability and maneuverability of the vehicle, and also to reduce the steering force, thereby realizing a vehicle with excellent steering response.

Furthermore, by detecting the steering angular velocity of the steering wheel, the caster angle can be reduced to reduce directional stability at the beginning or end of a turn of the vehicle in order to improve turning performance. Furthermore, during a certain turn, the caster angle can be increased to obtain a return force for the steering wheel, improving turning stability and providing a good feeling. Therefore, the steering stability performance of the vehicle can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram for explaining the principle of the variable suspension geometry device according to the present invention, FIG. Second
Figure (B) is a graph showing the relationship between the caster angle and steering angular velocity and time corresponding to the divisions shown in Figure 2 (A). FIG. 3 is a schematic diagram showing a variable suspension geometry device for a vehicle according to the present invention, FIG. 4 is a schematic front view showing an example of an adjustment device for changing the arm length of a vehicle suspension, and FIG. 5 is a schematic diagram showing a vehicle suspension geometry device. a schematic front view showing another example of an adjustment device for changing the arm length of the
Fig. 6 is a schematic diagram showing an example of a neutral position sensor that detects the neutral position of the steering wheel, Fig. 7 is a schematic diagram showing another example of a superposed position sensor that detects the neutral position of the steering wheel, and Fig. 8 (A) is a schematic diagram showing the installation status of the steering angular velocity sensor on the steering wheel;
FIG. 8(b) is a schematic diagram showing an example of the steering angular velocity sensor of the steering wheel, FIG. 9 is a schematic diagram showing another example of the steering angular velocity sensor of the steering wheel, and FIG.
FIG. 11 is a flowchart showing a state in which the caster angle is adjusted according to the vehicle speed by the signal of the neutral position of the steering wheel in the variable suspension geometry device according to the present invention, and FIG. 2 is a flowchart showing a state in which a caster angle is adjusted according to vehicle speed using an angular velocity signal. 1-------One vehicle, 2.3--One wheel, 4-・-
Control unit, 5--steering wheel, 6--vehicle speed sensor, 7--neutral position sensor,
10--Knuckle, 11.12--Upper link, 13.14--Lower link, 15.16.
17.18-・-stroke sensor, 21,22-・
1 connection point, 43.63--neutral position output signal, 67
---Steering angular velocity sensor, 84.88---Output signal of steering angular velocity, α--- Caster angle. Patent Applicant Isu Jidosha Co., Ltd. Agent Patent Attorney Onaka Sono 7 Figure 8 (A) @ 8
Figure (Q) is also Figure 9 Figure 10 Figure 11

Claims (5)

[Claims] (1) A variable suspension geometry device characterized in that it is provided with a sensor that detects the state of a steering wheel, and adjusts the caster angle of the suspension according to the vehicle speed based on a signal from the sensor. (2) The variable suspension geometry device according to claim 1, wherein the sensor is a neutral position sensor that detects a neutral position of the steering wheel. (3) The variable suspension geometry device according to claim 1, wherein the caster angle of the suspension is changed in accordance with vehicle speed when the steering wheel is in a neutral position. (4) The variable suspension geometry device according to claim 1, wherein the caster angle of the steering wheel is reduced when the steering wheel is in a position other than the neutral position. (5) The variable suspension geometry device according to claim 1, wherein the sensor is a steering angular velocity sensor that detects the rotational angular velocity of the steering wheel.