JPH0449027Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is a four-wheel steering vehicle (hereinafter referred to as
This article relates to the mounting structure of a front wheel steering angle detector in a 4WS vehicle (abbreviated as 4WS vehicle).

(Prior technology) In 4WS vehicles that use an actuator to steer the rear wheels in response to front wheel steering, the front wheel steering gearbox is mounted elastically on the vehicle body to absorb vibrations, external forces, etc. transmitted to the steering wheel. The rear wheel steering gearbox is also highly rigid and mounted on the vehicle body. This is because vibrations, external forces, etc. from the rear wheel steering device are not transmitted to the steering wheel, and the rear wheels are steered with high responsiveness relative to the vehicle body.

This invention has a front wheel steering angle detector built into the front wheel steering gearbox of such a 4WS vehicle, and the detector detects the amount of movement of a rod member such as a rack shaft incorporated in the gearbox in the vehicle width direction. The applicant proposed this in Japanese Patent Application No. Sho 61-196703 (see Japanese Unexamined Patent Publication No. Sho 63-52002).

(Problem that the invention aims to solve) However, since the gearbox with a built-in front wheel steering angle detector is mounted elastically on the vehicle body,
At the beginning of the steering behavior of the front wheels due to steering wheel operation, the gearbox moves along with the rod member in the width direction of the vehicle body due to the elasticity of its mount. For this reason, even though the front wheels are being steered, it may not be detected.

Therefore, the purpose of this invention is to provide a 4WS vehicle that uses an actuator to steer the rear wheels in response to front wheel steering.
Even if the front wheel steering gearbox is elastically mounted on the vehicle body, the front wheel steering system can accurately detect the front wheel turning relative to the vehicle body from the beginning of the front wheel turning behavior due to steering wheel operation over the entire range. To provide a mounting structure for an angle detector.

(Means for Solving the Problems) In order to solve the above problems and achieve the purpose, the present invention provides a front wheel steering device in which the gearbox 4 is elastically mounted on the vehicle body and interlocks with the steering wheel, and Front wheel steering angle detectors 21 and 31 which configure the device and detect the amount of movement in the vehicle width direction of the rod member 7 that is linked with front wheel steering; and the front wheel steering angle detectors 21 and 3.
In a 4WS vehicle equipped with a rear wheel steering device that steers the rear wheels by an actuator that operates in response to detection of front wheel steering according to No. 1, the front wheel steering angle is adjusted to detect the widthwise movement amount of the rod member 7 with respect to the vehicle body. The present invention is characterized in that the detectors 21 and 31 are mounted to the vehicle body without intervening the gearbox 4, and are prevented from moving in the width direction.

Specifically, a connecting rod 9 that is interlocked with the rod member 7 is provided, and the connecting rod 9 is movably inserted into the case 22 of the front wheel steering angle detector 21 to open the case 22. The case 37 of the front wheel steering angle detector 31 is mounted directly on the vehicle body or is housed in the gear box 4 so as to be relatively movable, and a connecting rod substantially parallel to the rod member 7 is provided between the case 37 and the vehicle body. 43 will be constructed.

(Function) Since the amount of movement of the bar member 7 in the width direction relative to the vehicle body is detected by the front wheel steering angle detectors 21 and 31 attached to the vehicle body to prevent movement in the width direction without using the front wheel steering gear box 4, Even if the gearbox 4 is elastically mounted on the vehicle body, the steering of the front wheels relative to the vehicle body can be accurately detected over the entire range from the initial stage of the steering behavior of the front wheels due to steering wheel operation. Therefore, the rear wheels can be steered constantly following the front wheels.

It is also possible to detect front wheel steering behavior caused by lateral forces such as crosswinds when traveling straight at high speed and steer the rear wheels in the same phase, allowing stable driving without the need for a separate control device for correction.

(Example) Examples will be described below based on the accompanying drawings.

1 and 2 are a schematic perspective view and the same plan view of a front wheel steering device, in which a pinion shaft 3 is connected to a steering shaft 2 of a handle 1, and this pinion shaft 3 is incorporated into a front wheel steering gear box 4. Furthermore, a rack shaft 7, which is a rod member extending in the width direction of the vehicle body, is incorporated into the gearbox 4. Knuckles 12 are connected to both ends of the rack shaft 7 via tie rods 11, and a front wheel 13 is supported on the knuckles 12. Although not shown, the gearbox 4 is movably mounted to the vehicle body via an elastic body in a known manner.

First, in the first embodiment, a perpendicular protruding rod part 8 is fixed to one end of a rack shaft 7 protruding from the gearbox 4, and a connecting rod 9 parallel to the rack shaft 7 is connected to this protruding rod part 8. Furthermore, this connecting rod 9 is incorporated into the front wheel steering angle detector 21. That is, the steering angle detector 21
A connecting rod 9 is inserted into the case 22 so as to be movable in the width direction of the vehicle body, and the case 22 is fixed and attached to a bracket 15 provided on the vehicle body with bolts 16.

Here, the front wheel steering angle detector 21 may be a non-contact type or a contact type that does not come into contact with the connecting rod 9, such as a differential transformer type, and the connecting rod 9 only needs to be approximately parallel to the rack shaft 7.

In the above, although not shown, the front wheel steering angle signal from the front wheel steering angle detector 21 is sent to the CPU as is known, and its output controls the operation of an actuator such as an electric motor provided in the rear wheel steering device, thereby changing the front wheel steering angle. The rear wheels are steered accordingly. In general, the 4WS system is adopted in which the front and rear wheels are steered in opposite phases for large steering angle operations performed at low to medium speeds, and in the same phase for small steering angle operations performed at high speeds.

The amount of movement of the rack shaft 7 in the width direction with respect to the vehicle body can be directly detected from the connecting rod 9 which is interlocked in parallel with the front wheel steering angle detector 21, which is attached to the front wheel steering angle detector 21 to prevent movement in the width direction with respect to the vehicle body. , even if the front wheel steering gearbox 4 is elastically mounted on the vehicle body, the front wheels 13 can be moved by operating the steering wheel 1.
This makes it possible to accurately detect the front wheel steering state of the vehicle body over the entire area from the beginning of the steering behavior.

This allows rear wheel steering to always follow front wheel steering.

Furthermore, even if the front wheels 13 turn as shown in the imaginary line in Figure 2 due to lateral forces such as crosswinds when driving straight ahead at high speeds without steering wheel operations, the front wheel steering angle detector 21 detects this. The rear wheels can also be steered in the same phase. Therefore, driving safety can be improved without separately providing a control device for correction.

Next, a second embodiment shown in FIG. 3 will be described.

The front wheel steering angle detector 31 is of a differential transformer type,
That is, a metal core 33 is connected to the outer periphery of the rack shaft 7 in the gear box 4 with a pin 32, and a metal core 33 is housed in the gear box 4 near the outer periphery of the metal core 33.
It consists of a secondary coil 34 and a secondary coil 35.
Both coils 34, 35 are connected to left and right circlips 36,
36 on the inner periphery of a cylindrical case 37, and this case 37 is slidably fitted on the inner periphery of a sleeve-shaped sliding bearing 38.

The sliding bearing 38 is fixed to the inner periphery of the gearbox 4, and holes 39, 5 are formed concentrically in the sliding bearing 38 and the gearbox 4, and a screw member 41 screwed onto the outer periphery of the case 37 protrudes from the holes 39, 5. . One end of a connecting rod 43 is pivotally connected to this screw member 41 via a pin 42 in the front-rear direction, and furthermore, this connecting rod 43 is arranged parallel or substantially parallel to the rack shaft 7, and a similar pin 44 is attached to the other end. A screw member 45 is pivotally attached. This screw member 45 is screwed and fixed to a bracket 18 provided on the vehicle body.

In the figure, 47 is a dust seal that covers the pivot joint between the case 37 and the connecting rod 43, and 6 is the gear box 4.
This is a sliding bearing for the rack shaft 7 guide provided at the end.

Here, the connecting rod 43 swings to some extent in the vertical and longitudinal directions together with the gearbox 4 due to the pivot joints at both ends, but the accompanying movement of the case in the left-right direction (vehicle width direction) is so small that it can be almost ignored. Very little.

The second embodiment can also provide the same effects as the first embodiment.

By the way, the rod member in the vehicle width direction constituting the front wheel steering device is not limited to the rack shaft, but may be a tie rod, or may be a screw shaft in a front wheel steering device equipped with an electric power assist device, for example.

(Effects of the invention) As described above, according to the invention, in a 4WS vehicle that steers the rear wheels using an actuator in response to front wheel steering, movement in the width direction relative to the vehicle body can be prevented without using the front wheel steering gearbox. The front wheel steering angle detector installed on the front wheel is configured to detect the widthwise movement of the rod member relative to the vehicle body, so even if the gearbox is elastically mounted on the vehicle body, the initial steering behavior of the front wheels due to steering wheel operation is detected. It is possible to accurately detect the steering of the front wheels relative to the vehicle body over the entire area from the front wheel to the vehicle body, and therefore the rear wheels can be steered in a manner that always follows the front wheel steering.

In addition, it is possible to detect front wheel steering behavior caused by lateral forces such as crosswinds when driving straight at high speed, and to steer the rear wheels in the same phase, resulting in stable driving without the need for a separate control device for correction. You can improve your sexuality.

[Brief explanation of the drawing]

1 and 2 are a schematic perspective view and a plan view of a front wheel steering system showing a first embodiment, and FIG. 3 is a longitudinal sectional front view of a main part showing a second embodiment. In the drawings, 1 is a handle, 4 is a gearbox, 7 is a rod member, 13 is a front wheel, 21 and 31 are front wheel steering angle detectors, 22 and 37 are a case, and 9 and 43 are connecting rods.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A front wheel steering device in which a gearbox is elastically mounted on the vehicle body and interlocks with the steering wheel, and the vehicle body width of a rod member that constitutes the front wheel steering device and is interlocked with front wheel steering. A four-wheel vehicle comprising: a front wheel steering angle detector that detects the amount of movement in a direction; and a rear wheel steering device that steers the rear wheels by an actuator that operates in response to detection of front wheel steering by the front wheel steering angle detector. In the steered vehicle, the front wheel steering angle detector is attached to the vehicle body without going through the gearbox to prevent widthwise movement of the rod member in order to detect the amount of widthwise movement of the rod member relative to the vehicle body. Mounting structure of a front wheel steering angle detector in a four-wheel steering vehicle. (2) In claim 1 of the utility model registration claim, a connecting rod is provided that interlocks in substantially parallel with the rod member, and the connecting rod is movably inserted into the case of the front wheel steering angle detector, A mounting structure for a front wheel steering angle detector in a four-wheel steering vehicle, characterized in that the case is directly attached to the vehicle body. (3) In claim 1 of the utility model registration claim, a case for the front wheel steering angle detector is housed in the gear box so as to be relatively movable, and the case is arranged between the case and the vehicle body substantially parallel to the rod member. A mounting structure for a front wheel steering angle detector in a four-wheel steering vehicle, characterized in that a connecting rod is installed.