JPH0138032B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a front and rear wheel steering control device for an automobile.

Conventional Technology In order to reduce the turning radius and improve maneuverability in automobiles, it is effective to use so-called front and rear wheel reverse phase steering, in which the rear wheels are steered in the opposite direction to the front wheels in conjunction with front wheel steering. It is well known that the above-mentioned reverse phase steering of the front and rear wheels significantly deteriorates steering stability during high-speed driving and is extremely dangerous.

Therefore, we focused on the fact that when driving at high speeds, the steering angle is generally small and large steering angles are not possible at high speeds.In the small steering angle range near straight-ahead driving, the front and rear wheels are steered in the same phase, and in other steering ranges, the front and rear wheels are steered in the same phase. A front and rear wheel steering device that provides wheel reverse phase steering has already been developed (see Japanese Patent Application Laid-Open No. 58-97565 and Japanese Patent Application Laid-Open No. 58-97566).

Problems to be Solved by the Invention However, since front and rear wheel in-phase steering essentially involves parallel movement of the vehicle body in the steering direction, it does not have the advantage of improving responsiveness during steering. However, in general steering, the change in the direction of the vehicle body is small and the so-called rudder effectiveness is slow, which is not necessarily preferable from the standpoint of steering performance.

In addition, reverse phase steering of the front and rear wheels has the great advantage of significantly reducing the turning radius of the vehicle body and improving maneuverability; however, the change in the direction of the vehicle body relative to steering is large, and it Not only does straight-line driving performance deteriorate when the vehicle turns, but the rear of the vehicle moves significantly toward the outer circumference of the turning circle, so there may be obstacles such as walls, utility poles, or curbs on the outer circumference of a bend in the road. In such a case, there is a risk that the rear part of the vehicle body will collide with an obstacle when turning, and there is also the problem that steering operation becomes unexpectedly difficult.

Considering the above, the conventional device described above, which steers the front and rear wheels in the same phase in a small steering angle range and reverses the front and rear wheels in other steering angle ranges, can be used for driving speeds of, for example, 40Km/h to 80Km. When driving at medium speeds such as /h for normal use and when driving at high speeds of 80km/h or more, the benefits of improving responsiveness during small steering turns and reducing the turning radius when turning corners are more important than the vehicle speed. Safety when driving a car, such as unnatural behavior where the change in the vehicle body suddenly changes from small to large when moving from a small steering angle range to a large steering angle range, and difficulty in steering operation. Disadvantages directly related to gender are more problematic, and although front and rear wheel steering is effective when making U-turns, parking in a garage, parallel parking, and other situations when approaching the vehicle, it is difficult to put it into practical use. It was something I didn't have.

Means for Solving the Problems The present invention provides a transmission mechanism that transmits the steering operation of a front wheel steering device to a rear wheel steering device, and a steering operation take-out shaft that rotates by the steering operation of the front wheel steering device and a rear wheel steering device. a gear set for transmitting operating force for front and rear wheel reverse phase steering and in-phase steering provided between the input shaft to the device;
It consists of a clutch that frees one or both of the two operating force transmission gear sets, a fork that switches and operates the clutch, and a rear wheel steering select lever that operates the fork. A lock member having a notch into which a protrusion provided on the fork fits and engages when the rear wheel steering system is in a straight-ahead state is fixed to an intermediate portion of the gear set for transmitting operating force, and the protrusion of the fork fits into the notch of the lock member. By fitting into and engaging with the fork, rotation of the input shaft can be restrained and the rear wheels can be held in a straight traveling state, and the switching operation of the clutch is performed by the protrusion of the fork passing through the notch of the lock member. and a cam surface for forcibly moving the rear wheel steering select lever to a neutral position in which the protrusion of the fork fits and engages with the notch of the lock member in conjunction with the selection operation of the gear shift lever to a high speed gear. It is characterized by the provision of a cam plate with a bulging shape.

Effect By adopting the above configuration, the driver can judge various situations and perform steering operations that require difficult driving techniques at low speeds, such as making U-turns or parking in the garage.
For example, when it is desirable to make the turning radius as small as possible, such as when making a U-turn, the rear wheel steering system is switched to reverse phase steering for the front and rear wheels. When entering and exiting from side-to-side parking when there is an obstacle on one side, the rear wheel steering system is switched to front and rear wheel in-phase steering to achieve a movement close to parallel movement, making full use of the advantages of the front and rear wheel steering system. As soon as the vehicle shifts from low speed to medium speed, the switching means automatically returns to the neutral position, and the rear wheel steering device is locked in the neutral position, that is, the straight-ahead position, from the normal medium speed driving range to the high speed driving range, and only the front wheel steering system is operated. By steering the vehicle, all of the inconveniences caused by front and rear wheel steering, such as unstable straight running and difficulty in steering operations, are eliminated.

Example The present invention will be explained below with reference to the accompanying drawings.

1 to 4 show embodiments of the present invention, in which 1 is a front wheel steering device;
For example, the pinion rotates as the steering handle 1a rotates, and the tie rods 1c, 1c and the knuckle arms 1d, which mesh with the pinion and slide in the axial direction as the pinion rotates.
The steering gear box 1 is connected to a rack shaft that rotates the front wheels 2, 2 around the kingpin via the steering gear box 1, etc.
A so-called pinion-rack type steering system is used, which is built into the engine.

3 is a steering operation take-out shaft of the front wheel steering device 1;
For example, the steering operation take-out pinion that meshes with the rack shaft of the front wheel steering device 1 is connected to the steering box 1.
b, and the front end of the steering operation take-out shaft 3 is connected to the steering operation take-out pinion by a joint or the like, so that the turning operation take-out shaft 3 is rotated by the steering operation of the front wheel steering device 1. It's getting old.

Reference numeral 4 denotes an input shaft to the rear wheel steering system, and the rear end of the input shaft 4 is, for example, of the pinion rack type in which a pinion and a rack shaft with which the pinion meshes are built into the gearbox 5a, similar to the front wheel side. connected to the pinion of the rear wheel steering device 5 via a joint or the like;
The rotation of the input shaft 4 causes the rack shaft to operate in the axial direction, and the tie rods 5b, 5b and the knuckle arm 5
The rear wheel 6 is rotated to the left and right through the wheels c, 5c, etc.

Gears 31 and 32 are attached to the extraction shaft 3 so as to be fixed in the axial direction but free to rotate, and the input shaft 4 has a gear 41 that directly meshes with the gear 31 and an intermediate gear 7 that meshes with the gear 32. Meshing gears 42
is fixed.

Further, a clutch 8 having clutch teeth that mesh with the clutch meshing teeth 31a and 32a of the gears 31 and 32 is fitted onto the extraction shaft 3 so as to be fixed in the rotational direction and slidable in the axial direction. When the clutch 8 meshes with the clutch meshing teeth 31a of the gear 31, the steering operation of the front wheel steering device 1 is transmitted from the gear 31 to the rear wheel steering device 5 via the gear 41, and the rear wheels are steered in the opposite direction to the front wheels. , clutch 8 is gear 3
When the clutch meshing teeth 32a of 2 are engaged, the steering operation of the front wheel steering device 1 is transmitted to the rear wheel steering device 5 via the gear 32, the intermediate gear 7, and the gear 42, so that the rear wheels are steered in the same direction as the front wheels. It's getting old.

Reference numeral 9 denotes a rear wheel steering select lever, and by operating the rear wheel steering select lever 9 in the longitudinal direction, the rod 10 is actuated in the axial direction, and the fork 12 is actuated in the longitudinal direction via the spring 11. Slide the clutch 8 and turn the gear 31 or 32
The meshing and disengagement can be controlled.

The fork 12 is engaged with notches 13a, 13a of a locking member 13 fixed at an intermediate position between the gears 41 and 42 of the input shaft 4, and is engaged with the rear wheel steering device 5.
protrusion 1 that locks the vehicle in a neutral position, that is, in a straight-ahead position;
2a and 12a are provided.

Reference numeral 14 denotes a cam plate supported on the vehicle body so as to slide in the left-right direction in conjunction with the selection operation of the gear shift lever 15, that is, the rotational movement in the left-right direction, and not to move in the front-rear direction. 14a does not interfere with the rear wheel steering select lever 9 when the gear shift lever 15 is in the 1st or 2nd speed selection position or in the reverse R selection position as shown in FIGS. 1 and 2A, The rear wheel steering select lever 9 can be freely operated to the rear wheel reverse phase steering position 9' or the rear wheel in-phase steering position 9'' as shown by the dotted line in FIG.
When the gear shift lever 15 is operated from the 1st and 2nd gear select positions to the high gears, that is, the 3rd and 4th gear select positions, the cam plate 14 slides from the state shown in FIG. Alternatively, the rear wheel steering select lever 9 located at the 9'' position is returned to the neutral position by the cam surface 14a as shown in FIG. .

In the figure, 16 is a bearing.

In the above configuration, when a small turn of the vehicle body is required at low speed, such as when making a U-turn, parking in a garage, parallel parking, or side-by-side parking, the driver uses reverse phase steering for the front and rear wheels to reduce the turning radius based on the situation. However, it is better to use front and rear wheel steering in the same phase, or to move the vehicle diagonally forward or diagonally backward in a state that is close to parallel movement. For example, when making a U-turn, use the rear wheel steering select lever 9. Operate forward and clutch 8
is engaged with the meshing teeth 31a of the gear 31 to set the front and rear wheels in a reverse phase steering state (see Fig. 3B), perform a U-turn with a small turning radius, and select rear wheel steering when parallel parking where there is little room in the front and rear directions. Operate the lever 9 backward to move the clutch 8 to the meshing teeth 32a of the gear 32.
(see Figure 3 C) to achieve the same phase steering for the front and rear wheels, and by moving the vehicle body in a nearly parallel motion, the objective can be easily achieved, thereby significantly improving maneuverability at low speeds. be able to.

When shifting to normal driving, when the gear shift lever 15 is operated to select from the low speeds of 1st and 2nd gears to the higher speeds of 3rd and 4th gears, the cam plate 14 moves in conjunction with the selection operation, and the cam surface 14a moves The rear wheel steering select lever 9, which is in the steering position where the front and rear wheels are in opposite phase or in phase, is forcibly returned to the neutral position and locked at that position, and the clutch 8 is moved to either gear 31 or 32 as shown in Fig. 3A. The protrusions 12a, 12a of the fork 12 are held in a neutral position in which they do not engage with each other, and the protrusions 12a, 12a of the fork 12 are held in the notch 13 of the lock member 13.
a, 13a to lock the rear wheel steering device 5 in the straight-ahead state, and when the gear is shifted to the 3rd or 4th speed for general medium-speed driving or high-speed driving, only the front wheels are steered and the vehicle is driven straight. This makes it possible to significantly improve steering stability and steering stability.

When the clutch 8 is engaged with the gears 31 or 32 by manual operation of the rear wheel steering select lever 9 as described above, the clutch 8 will not engage with the clutch meshing teeth 31a, 32a unless both the front and rear wheels are in a straight-ahead state. Teeth of clutch 8 and clutch meshing teeth 31
a and 32a have a configuration in which the tooth shape is partially changed, and when switching from front and rear wheel reverse phase steering to front and rear wheel in-phase steering, or vice versa, the rear wheels are rotated as shown in Figure 4B. If the fork 12 is not running straight, the protrusion 12a of the fork 12 hits the lock member 13, making it impossible to perform a switching operation. When the rear wheels return to the straight drive state, the notch 13a of the lock member 13 and the protrusion as shown in FIG. 12a match, the fork 13 passes back and forth to perform switching, and when switching between reverse phase steering and in-phase steering as described above, and when the cam plate 1
When the rear wheel steering select lever 9 is automatically returned to the neutral position by 4, the waiting time for the rear wheels to return to the straight traveling state can be absorbed by the expansion and contraction of the spring 11.

Effects of the Invention As described above, according to the present invention, the driver can arbitrarily select front and rear wheel reverse phase steering or front and rear wheel in-phase steering in the low speed range of the automobile, and the advantage of front and rear wheel steering is the ability to turn around at low speeds. In addition to significantly improving
The rear wheel steering system is automatically locked in the straight-ahead state, that is, the neutral position, as soon as the vehicle shifts to normal driving at medium to high speeds, and the steering is switched to steering only the front wheels. This improves straight-line driving performance during normal driving. It is possible to significantly improve the steering stability associated with this, and it is possible to bring about a great practical effect.

[Brief explanation of drawings]

Fig. 1 is a schematic perspective view of the front and rear wheel steering system showing one embodiment of the present invention, Fig. 2 A and B are plan views showing the operating mode of the cam plate in Fig. 1, and Fig. 3 A, B and C are respectively shown. 1 is a diagram showing the meshing mode of the gears in FIG. 1, where A shows the neutral state, B shows the front and rear wheels in a reverse phase steering state, and C shows the front and rear wheels in the same phase steered state. 4A and 4B are perspective views showing the relationship between the fork and the lock member of FIG. 1, respectively. 1...Front wheel steering device, 3...Steering operation take-out shaft,
4... Input shaft, 31, 32, 41, 42... Gear, 5... Rear wheel steering device, 7... Intermediate gear, 8...
...Clutch, 9...Rear wheel steering select lever, 1
0...Rod, 11...Spring, 12...Fork, 12a...Protrusion, 13...Lock member,
13a... Notch, 14... Cam plate, 15
...Gear shift lever.

Claims (1)

[Claims] 1. A transmission mechanism for transmitting the steering operation of the front wheel steering device to the rear wheel steering device is provided between the steering operation output shaft that rotates due to the steering operation of the front wheel steering device and the input shaft to the rear wheel steering device. A gear set for transmitting operating force for front and rear wheel reverse phase steering and in-phase steering, a clutch for freeing one or both of the two gear sets for transmitting operating force, and a fork for switching and operating the clutch. , and a rear wheel steering select lever for operating the fork, and a protrusion provided on the fork is fitted into an intermediate portion of the two operating force transmission gear sets of the input shaft when the rear wheel steering system is in a straight-ahead state. A lock member having a matching notch is fixed, and the protrusion of the fork fits and engages with the notch of the lock member, thereby restraining rotation of the input shaft and holding the rear wheel in a straight-ahead state. The switching operation is performed by the protrusion of the fork passing through the notch of the locking member,
A cam plate having a cam surface that forcibly moves the rear wheel steering select lever to a neutral position where the protrusion of the fork fits and engages with the notch of the lock member in conjunction with the selection operation of the gear shift lever to a high speed gear. What is claimed is: 1. A front and rear wheel steering control device for an automobile, characterized in that: