JP2005335644A - Wheel alignment adjusting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel alignment adjusting apparatus capable of adjusting alignment variation accompanying height adjustment using one actuator without causing steering neutral displacement. <P>SOLUTION: The wheel alignment adjusting apparatus comprises height adjusting means (left and right air suspensions 11a and 11b) for adjusting the height of a vehicle, a rudder angle ratio variable actuator 5 capable of varying the rudder angle ratio, namely, the ratio of the front wheel rudder angle to the steering angle, a toe angle adjusting actuator 12 that is disposed only on the right front wheel 2b side of the left and right front wheels 2a and 2b and can vary one toe angle variation amount of the right front wheel 2b, and a control unit 16 which outputs an alignment adjusting command of adjusting the toe angle variation amount accompanying the height adjustment to the toe angle adjusting actuator 12 and outputs a rudder angle ratio variable command of correcting the steering neutral displacement amount accompanying the alignment adjustment to the rudder angle ratio variable actuator 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to the technical field of a wheel alignment adjusting device that adjusts a change in wheel alignment accompanying a vehicle height adjustment.

As this type of prior art, a suspension device is known in which a toe angle adjusting actuator is provided on each of the left and right front wheel suspension links in order to adjust a change in toe angle associated with vehicle height adjustment (for example, Patent Documents). 1).
JP-A-9-71115

  However, since the toe angle adjusting actuators are arranged on the left and right suspension links in the above-described conventional technology, two actuators are necessary, and variation management of the left and right actuators (for example, the same characteristics on the left and right) For example, it is necessary to sort out what has become.

  The present invention has been made paying attention to the above-mentioned problem, and the object of the present invention is to provide a wheel alignment adjustment device capable of adjusting an alignment change accompanying a vehicle height adjustment using one actuator without causing a steering neutral shift. Is to provide.

In order to achieve the above object, the present invention provides:
Vehicle height adjusting means for adjusting the vehicle height;
Rudder angle ratio variable means for varying the rudder angle ratio, which is the ratio of the front wheel rudder angle to the steering angle,
An alignment variable means that is provided only on one side of the left and right front wheels and varies the wheel alignment of one of the left and right front wheels;
An alignment adjustment control means for outputting an alignment adjustment command for adjusting the amount of change in alignment accompanying the vehicle height adjustment to the alignment variable means,
Rudder angle ratio control means for outputting a rudder angle ratio variable command for correcting a steering neutral deviation amount accompanying the alignment adjustment to the rudder angle ratio variable means;
It is characterized by providing.

  In the wheel alignment adjusting device of the present invention, the steering angle ratio variable means is used to correct the steering neutral shift caused by the alignment adjustment. Therefore, the vehicle height adjustment can be performed using one actuator without causing the steering neutral shift. The accompanying alignment change can be adjusted.

  Hereinafter, the best mode for carrying out the present invention will be described based on the first embodiment.

First, the configuration will be described.
FIG. 1 is a system block diagram of a vehicle to which the wheel alignment adjusting device according to the first embodiment is applied.

  The steering wheel 1 is connected to the upper column shaft 4a, and the steering mechanism 3 for turning the left and right front wheels 2a and 2b is connected to the lower column shaft 4b. A steering angle ratio variable actuator 5 is provided between the upper column shaft 4a and the lower column shaft 4b.

  The steering angle ratio variable actuator 5 includes a motor 5a and a speed reducer 5b. The rotation angle input from the steering wheel 1 to the upper column shaft 4a is decelerated by the variable steering angle ratio and is output to the lower column shaft 4b. Thus, the steering angle ratio, which is the ratio of the steering angle to the steering angle, is variably controlled. The motor 5 a of the steering angle ratio variable actuator 5 is controlled by a steering angle ratio variable command from the control unit 16.

  The steering mechanism 3 includes a steering gear 6 connected to the lower end portion of the steering shaft 4, a steering rack 7 that meshes with the steering gear 6 and moves in the vehicle width direction, and left and right tie rods 8a and 8b connected to both ends of the steering rack 7. And left and right tie rods 8a and 8b and left and right knuckle spindles 10a and 10b, and left and right knuckle arms 9a and 9b.

  Air suspensions (vehicle height adjusting means) 11a and 11b are provided between the knuckle spindles 10a and 10b and the vehicle body. The air suspensions 11 a and 11 b adjust the vehicle height of the vehicle by changing the spring pressure according to the vehicle height adjustment command from the control unit 16. An air suspension that adjusts the vehicle height by a vehicle height adjustment command from the control unit 16 is also provided between the left and right rear wheels (not shown) and the vehicle body.

  A toe angle adjusting actuator (alignment varying means) 12 for adjusting the toe angle of the right front wheel 2b is provided on the right tie rod 8b constituting the suspension link of the right front wheel 2b. For example, a hydraulic cylinder is used as the toe angle adjusting actuator 12 and expands and contracts in the axial direction in accordance with an alignment adjustment command from the control unit 16 to adjust the toe angle of the right front wheel 2b. Here, the “toe angle” refers to an angle formed by the height of the center of the axle between the front-rear direction center plane of the vehicle and the center plane of the wheel on one side.

  The control unit 16 sets a target steering angle ratio according to the steering angle signal from the steering angle sensor 13 and the vehicle speed signal from the vehicle speed sensor (vehicle speed detection means) 14, and the steering angle based on this target steering angle ratio. Steering angle ratio variable control for outputting a steering angle ratio variable command to the motor 5a of the variable ratio actuator 5 is performed.

  The control unit 16 is provided in the vehicle interior and outputs a vehicle height adjustment command for changing the spring pressure to the air suspensions 11a and 11b according to the state of the vehicle height adjustment switch 17 operated by the driver. Implement high adjustment control.

  After executing the vehicle height adjustment control, the control unit 16 calculates the amount of change in the toe angle caused by the vehicle height adjustment from the vehicle height signal from the vehicle height sensor (vehicle height detection means) 15 and the suspension design characteristics of the vehicle. In addition, the toe angle of the right front wheel 2b is adjusted according to the calculation result, and the alignment adjustment control for correcting the steering neutral shift associated with the alignment adjustment control using the steering angle ratio variable actuator 5 is performed.

Next, the operation will be described.
[Wheel alignment adjustment control processing]
FIG. 2 is a flowchart showing the flow of the wheel alignment adjustment control process executed by the control unit 16, and each step will be described below. This control is started when the vehicle height adjustment is executed.

  In step S1, the average value of the output of the vehicle height sensor 15 or the vehicle height adjustment command value output from the vehicle height adjustment switch 17 is read, and the process proceeds to step S2.

  In step S2, from the average value of the output of the vehicle height sensor 15 read in step S1 (or the vehicle height adjustment command value output from the vehicle height adjustment switch 17) and the suspension design characteristics of the vehicle, the vehicle height adjustment is accompanied. The toe angle change amount θ is calculated, and the process proceeds to step S3. Here, the toe angle change amount θ uses a suspension design characteristic map set in advance as shown in FIG.

  In step S3, a toe angle adjustment command value that is twice (2θ) the toe angle change amount θ calculated in step S2 is output to the toe angle adjustment actuator 12 (alignment adjustment control means), and the process proceeds to step S4.

  In step S4, the steering angle ratio variable command value added with the steering neutral deviation correction amount θ generated by the toe angle adjustment is output to the steering angle ratio variable actuator 5 (steering angle ratio control means), and the process proceeds to return.

  In the first embodiment, the alignment adjustment at step S3 and the steering neutral deviation correction at step S4 are not always performed after the calculation of the toe angle change amount θ, but the vehicle speed exceeds a preset vehicle speed threshold value. This is done only occasionally, and not in extremely low speed areas such as when the vehicle is stopped or when entering the garage.

[Steering neutral deviation correction by variable rudder angle ratio]
In the combination of the conventional vehicle height adjustment variable system and the steering angle ratio variable actuator, the response characteristics of the vehicle to the driver's steering can be corrected or optimized. However, as shown in FIG. May cause the wheel alignment to deviate significantly from the proper value. Furthermore, changes in vehicle characteristics due to poor alignment cannot be prevented.

  For example, as shown in FIG. 4, an idea such as a low vehicle height for improving fuel efficiency during high-speed traveling and a high vehicle height for increasing clearance under the floor during low-speed traveling is common. However, with an independent suspension type suspension or the like, there is a possibility that the toe-out becomes larger as the vehicle height is lowered from the vehicle reference vehicle height, and the adverse effect such as deterioration of the straight running stability during high speed running may occur.

  In order to solve the above problem, in the suspension apparatus described in Japanese Patent Laid-Open No. 9-71115, a toe angle adjusting actuator is disposed on the right front wheel side suspension link as shown in FIG. In order to prevent the steering neutral shift that accompanies this, it is necessary to dispose the same actuator on each of the left and right front wheels.

  For this reason, only the correction of the toe angle of the front wheels requires two actuators, resulting in high costs, and the characteristics of the left and right actuators must be matched (if the characteristics do not match, neutral deviation will occur). Problems arise.

  On the other hand, in the wheel alignment adjusting device of the first embodiment, the wheel alignment (toe angle) is corrected by using one toe angle adjusting actuator 12, and the neutral deviation resulting therefrom is corrected by the steering angle ratio variable actuator 5. As a result, it is possible to maintain the appropriateness of the wheel alignment and solve the problem of cost increase and variation management due to the use of a separate wheel alignment correcting actuator.

[Wheel alignment adjustment]
FIG. 6 is an explanatory diagram illustrating the wheel alignment adjustment function of the first embodiment.
When the vehicle height adjustment switch 17 is operated on the low vehicle height side by the driver, as shown in FIG. 6 (a), toe out is generated on the left and right front wheels 2a, 2b that has a toe angle change amount θ accompanying a decrease in vehicle height. .

  When the vehicle height changes from the reference vehicle height, the control unit 16 calculates the toe angle change amount θ from the average value of the output of the vehicle height sensor 15 and the suspension design characteristic map, and the right front wheel is moved to the toe angle adjusting actuator 12. A toe angle adjustment command value for turning the toe angle of 2b to the left by 2θ is output. By adjusting the toe angle, as shown in FIG. 6B, the tire turning angles of the left and right front wheels 2a and 2b coincide.

  At this time, since the left and right front wheels 2a and 2b are cut by θ on the left side, the left and right front wheels 2a and 2b are cut to the left side even though the steering wheel 1 is in the neutral position. Yes.

  Therefore, as shown in FIG. 6C, when the driver returns the left and right front wheels 2a and 2b to the neutral position in order to go straight ahead, the steering wheel 1 is steered to the right by the amount corresponding to the steering angle of θ from the neutral position. As a result, the neutral position of the steering wheel 1 and the neutral position of the left and right front wheels 2a and 2b do not coincide with each other.

  Here, the control unit 16 outputs a steering angle ratio variable command value for correcting the steering neutral deviation correction amount θ to the steering angle ratio variable actuator 5. Thereby, the steering neutral shift accompanying alignment adjustment can be corrected.

[Wheel alignment adjustment function according to vehicle speed]
When the alignment adjustment control is performed while the vehicle is stopped, there is a possibility that the steering wheel 1 may move freely. Further, in order to steer the left and right front wheels 2a and 2b while the vehicle is stopped, a large output is required for the toe angle adjusting actuator 12 and the steering angle ratio variable actuator 5.

  Therefore, in the first embodiment, the alignment adjustment control is performed when the vehicle speed exceeds the vehicle speed threshold value, thereby preventing problems such as the unexpected rotation of the steering wheel 1 of the driver and the enlargement of the actuator described above. ing.

  At this time, since the control unit 16 calculates the toe angle change amount θ from the average value of the output of the vehicle height sensor 15, even when the sensor output varies due to the vertical movement of the vehicle body during traveling, a more accurate toe angle is obtained. The angle change amount θ can be calculated.

Next, the effect will be described.
In the wheel alignment adjusting device of the first embodiment, the effects listed below can be obtained.

  (1) Vehicle height adjusting means (left and right air suspensions 11a and 11b) for adjusting the vehicle height of the vehicle, a steering angle ratio variable actuator 5 for changing a steering angle ratio which is a ratio of a front wheel steering angle to a steering steering angle, An alignment variable means (toe angle adjusting actuator 12) that is provided only on the right front wheel 2b side of the front wheels 2a and 2b and changes the wheel alignment of one of the right front wheels 2b, and an alignment associated with the vehicle height adjustment with respect to this alignment variable means A steering angle ratio variable command for correcting the steering neutral shift amount accompanying the alignment adjustment is output to the alignment adjustment control means (control unit 16) that outputs an alignment adjustment command for adjusting the change amount and the steering angle ratio variable actuator 5. And a steering angle ratio control means (control unit 16). The alignment change accompanying the vehicle height adjustment can be adjusted by using one alignment adjusting actuator.

  In addition, since only one alignment adjustment actuator is required, there is no need to match the characteristics of the left and right actuators. Further, when applied to a vehicle equipped with a steering angle ratio variable mechanism, only one alignment variable means is added. Therefore, the cost can be greatly reduced as compared with the conventional apparatus.

  (2) The alignment adjustment control means outputs an alignment adjustment command that is twice the alignment change amount, and the steering angle ratio control means outputs a steering angle ratio variable command corresponding to the alignment change amount. Thus, the steering neutral shift can be reliably corrected by the steering angle ratio variable actuator 5 while ensuring the alignment of the left and right front wheels 2a and 2b.

  (3) The alignment variable means is the toe angle adjusting actuator 12, and the alignment adjustment control means is a means for adjusting the toe angle change amount accompanying the vehicle height adjustment. The toe-out can be corrected and the straight running stability can be prevented from deteriorating.

  (4) A vehicle speed sensor 14 for detecting the vehicle speed of the host vehicle is provided, and the alignment adjustment control means adjusts the alignment when the vehicle speed exceeds the vehicle speed threshold value. The rotation of the steering wheel 1 and the increase in size of the actuator can be prevented.

  (5) A vehicle height sensor 15 for detecting the vehicle height is provided, and the alignment adjustment control means calculates the amount of change in alignment based on the average value of the output of the vehicle height sensor 15. Even when the output varies, a more accurate toe angle change amount θ can be obtained.

(Other examples)
As described above, the wheel alignment adjusting device of the present invention has been described based on the first embodiment. However, the specific configuration is not limited to the first embodiment. For example, in the first embodiment, the amount of change in the toe angle is described. In the above example, the suspension is calculated using the suspension design characteristic map.

  In the first embodiment, when the vehicle speed exceeds the vehicle speed threshold value, the toe angle adjustment and the steering neutral deviation correction are performed. However, the toe angle adjustment and the steering neutral deviation are gradually performed as the vehicle speed increases. It is good also as composition which performs amendment.

  In the first embodiment, an example in which a toe angle adjusting actuator is provided as the alignment varying means has been described. However, a configuration in which a camber angle adjusting actuator that varies the camber angle may be provided. Here, the camber angle refers to an angle between the center line of the tire and a vertical line when the vehicle is viewed from the front.

  Moreover, it is good also as a structure which provided both the toe angle adjustment actuator and the camber angle adjustment actuator. In this case, the conventional apparatus requires a total of four actuators, whereas in the present invention, each actuator may be provided only on one side of the left and right front wheels, for a total of two.

  In the first embodiment, the toe angle adjusting actuator is provided on the right tie rod. However, the installation position of the alignment variable means is not limited to the tie rod, and can be installed at an arbitrary position in the suspension link.

1 is a system block diagram of a vehicle to which a wheel alignment adjusting device according to a first embodiment is applied. 4 is a flowchart showing a flow of wheel alignment adjustment control processing executed by a control unit 16. FIG. 6 is a characteristic diagram (suspension design characteristic map) showing a relationship between a change in vehicle height and a change in toe angle in an independent suspension type suspension. It is explanatory drawing which shows the problem of a prior art. It is a figure which shows the structure of the conventional suspension apparatus. It is explanatory drawing which shows the vehicle height adjustment effect | action of Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering wheel 2a Left front wheel 2b Right front wheel 3 Steering mechanism 4a Upper column shaft 4b Lower column shaft 5 Steering angle ratio variable actuator 5a Motor 5b Reduction gear 6 Steering gear 7 Steering rack 8a Left tie rod 8b Right tie rod 9a Left knuckle arm 9b Right knuckle Arm 10a Left knuckle spindle 10b Right knuckle spindle 11a Left air suspension 11b Right air suspension 12 Toe angle adjustment actuator 13 Steering angle sensor 14 Vehicle speed sensor 15 Vehicle height sensor 16 Control unit 17 Vehicle height adjustment switch

Claims (5)

Vehicle height adjusting means for adjusting the vehicle height;
Rudder angle ratio variable means for varying the rudder angle ratio, which is the ratio of the front wheel rudder angle to the steering angle,
An alignment variable means that is provided only on one side of the left and right front wheels and varies the wheel alignment of one of the left and right front wheels;
An alignment adjustment control means for outputting an alignment adjustment command for adjusting the amount of change in alignment accompanying the vehicle height adjustment to the alignment variable means,
Rudder angle ratio control means for outputting a rudder angle ratio variable command for correcting a steering neutral deviation amount accompanying the alignment adjustment to the rudder angle ratio variable means;
A wheel alignment adjusting device comprising: In the wheel alignment adjusting device according to claim 1,
The alignment adjustment control means outputs an alignment adjustment command that is twice the amount of alignment change,
The steering angle ratio control means outputs a steering angle ratio variable command corresponding to the alignment change amount. In the wheel alignment adjusting device according to claim 1 or 2,
The alignment variable means is a toe angle variable means,
The wheel alignment adjustment device according to claim 1, wherein the alignment adjustment control means is a means for adjusting a toe angle change amount accompanying a vehicle height adjustment. The wheel alignment adjusting device according to any one of claims 1 to 3, further comprising vehicle speed detecting means for detecting the vehicle speed of the host vehicle,
The wheel alignment adjustment device according to claim 1, wherein the alignment adjustment control means performs alignment adjustment when the vehicle speed exceeds a vehicle speed threshold value. In the wheel alignment adjusting device according to any one of claims 1 to 4,
A vehicle height detection means for detecting the vehicle height is provided,
The said alignment adjustment control means calculates an alignment variation | change_quantity according to the average value of the output of a vehicle height detection means, The wheel alignment adjustment apparatus characterized by the above-mentioned.

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