JP2525414Y2 - Self-propelled vehicle steering system - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering device for a self-propelled vehicle such as a speed sprayer, and more particularly, to a steering device for a self-propelled vehicle capable of achieving both small turning and safe driving at high speed.

[0002]

2. Description of the Related Art Japanese Utility Model Laid-Open Publication No. 63-65569 discloses a four-wheel steering system in which the rear wheels are steered in the same direction or in the opposite direction to the steering of the front wheels. Also, Japanese Unexamined Patent Publication No.
Japanese Patent Application Publication No. 128053 describes an apparatus provided with a dead zone setting means for setting a dead zone in the rear wheel steering angle characteristic for front wheel steering so that the rear wheel steering angle is kept at zero within a small range of the front wheel steering angle. ing. Further, JP-A-2-29
Japanese Unexamined Patent Publication No. 3223 discloses a technique capable of increasing the width of a self-propelled vehicle, parallel parking, and the like using all-wheel steering in opposite phases. In all-wheel steering in the opposite phase, small turning is ensured, but safety in the case of a course change during high-speed running is reduced.
On the other hand, in a passenger car or the like, the four-wheel steering is switched between the same phase and the opposite phase depending on the vehicle speed or the steering angle in order to achieve both small turning and stable traveling performance such as a course change at a high speed traveling. Also, a hydraulic steering device capable of manually switching between four-wheel steering and two-wheel steering is known.

[0003]

The structure of a four-wheel steering system capable of switching between in-phase and anti-phase is complicated. It is complicated to manually switch between four-wheel steering and two-wheel steering, and there is a danger in the case where the anti-phase four-wheel steering is performed during high-speed running due to an erroneous operation.

Accordingly, Japanese Patent Application No. 3-105 of the present applicant has
No. 756 is a steering device for a self-propelled vehicle that simplifies the structure while achieving both small turning and stability during high-speed running by omitting the trouble of manual operation, and in the range where the operation amount of the steering wheel is small, Disclosed is a configuration in which the two-wheel steering of only the front wheels is performed and the steering amount of the steering wheel is sufficiently increased, and then the steering of the rear wheels in the opposite phase is started.

[0005] The purpose of this invention is that of Japanese Patent Application No. Hei 3-10575.
It is an object of the present invention to provide an all-wheel steering system for a self-propelled vehicle that achieves the same object as in No. 6 by another configuration.

[0006]

The present invention will be described with reference to the drawings corresponding to the embodiments. The steering device of the self-propelled vehicle (10) of the present invention has the following components (a) to (f). (A) a rotating member (38) that is rotated in accordance with the amount of operation of the steering wheel (28); (b) connected to one end of the rotating member (38) via a front wheel side connection point (43b) to be connected to the front wheel side Front wheel steering link means (58) for transmitting the displacement of the point (43b) to the front wheel (12) (c) The rear wheel is connected to the other end of the rotating member (38) via the rear wheel side connection point (43a) A rear wheel steering link means (60) for transmitting the displacement of the side connection point (43a) to the rear wheel (14); (d) an intermediate portion (42) of the rotating member (38) in the front-rear direction of the self-propelled vehicle (10) (E) a biasing means (92) for biasing the rear wheel (14) in the straight traveling direction of the self-propelled vehicle (10); (f) a maximum value of the steering angle of the front wheel (12). Limiting stopper (8
8)

[0007]

The rotation member (38) is about to be rotated according to the operation force based on the operation amount of the steering wheel (28). The rear wheel (14) is urged by the urging means (92) in the straight traveling direction of the self-propelled vehicle (10), and the urging force of the urging means (92) is
Acts on the rotating member (38) as a resistance to the steering force of the rotating member (38), and therefore, against the rotating force of the rotating member (38). On the other hand, when the front wheel (12) has a steering angle smaller than the maximum value, the stopper (8
Steering is free without being restricted by 8). As a result, the rotating member (38) is substantially centered on the rear wheel side connection point (43a) while the lateral displacement of the self-propelled vehicle (10) is restricted by the guide means (84) at the intermediate portion (42). The front wheel-side connection point (43b) rotates and the rear wheel-side connection point (43a) is suppressed from rotating. Thus, the rotational displacement of the rotating member (38) at the front wheel side connection point (43b) is transmitted to the front wheel (12) via the front wheel steering link means (58), and the front wheel (12) operates the steering wheel (28). Steering in positive phase is related to the quantity.

When the operation amount of the steering wheel (28) becomes sufficiently large, the steering angle of the front wheels (12) reaches a maximum value,
Further increase is limited by the stopper (88). Thereby, the rotation member (38) is substantially centered on the front wheel side connection point (43b) while the lateral displacement of the self-propelled vehicle (10) is restricted by the guide means (84) at the intermediate portion (42). Energizing means (9
The rear wheel side connection point (43a) is rotationally displaced against the rear wheel side connection point (43a), and the rotational displacement of the rotating member (38) at the rear wheel side connection point (43a) is shifted rearward via the rear wheel steering link means (60). It is transmitted to the wheel side connection point (43a), and the rear wheel side connection point (43a) is connected to the steering wheel (28).
Is steered in the opposite phase in relation to the amount of operation of.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 5 is a schematic side view of the speed sprayer 10. The speed sprayer 10 is of a four-wheel drive and four-wheel steering type, and includes a frame 16 supported by a front wheel 12 and a rear wheel 14 and capable of self-running. flame
On the upper side of 16, a driver's seat 18 in order from the front of the speed sprayer 10, a chemical solution tank 20 for storing a chemical solution, a hood 22 surrounding an engine room containing a traveling engine, etc., a jet head 24 for discharging a spray of the chemical solution, and A blower 26 that discharges air sucked from behind to the jet head 24 is mounted.

FIG. 1 is a configuration diagram of a steering device of the speed sprayer 10. As shown in FIG. The rotation of the steering wheel 28 is transmitted to the all-hydraulic power steering device 30, and the all-hydraulic power steering device 30 changes the hydraulic pressure sent from the oil pump 33 through the flow control valve 32 in the rotation direction of the steering wheel 28. It switches in relation and sends to oilway 34 or oilway 35. The expansion and contraction of the steering cylinder 36 is controlled by the hydraulic pressure sent from the oil passages 34 and 35, and the steering cylinder 36 is rotatably connected at both ends to the frame 16 and the rearwardly extending portion 40 of the rotating member 38. The rotating member 38 includes a left overhanging portion 41a and a right overhanging portion 41b in addition to the rear overhanging portion 40, and a shaft 42 located at the center. Bracket 82 is a frame
The speed sprayer 10 is fixed to 16 and inserted through the shaft 42.
Has a guide hole 84 for guiding in the front-rear direction. The connection points 43a and 43b at the front end of the rear wheel drag link 60 and the rear end of the front wheel drag link 58 are rotatably connected to the left overhang portion 41a and the right overhang portion 41b, respectively.

Each front wheel 12 is rotatably supported by a knuckle 46. The knuckle 46 is rotatable about a vertical line integrally with a knuckle arm 48. Tie rods 50 are provided at both ends of the left and right knuckle arms 48. It is rotatably connected to the end. Similarly, each rear wheel 14 is rotatably supported by a knuckle 52, the knuckle 52 is rotatable integrally with a knuckle arm 54 about a vertical line, and a tie rod 56 is provided at both ends with left and right knuckle arms 54. Is rotatably connected to the end of the. The front wheel drag link 58 has a front end rotatably connected to the left knuckle arm 48 and a rear wheel drag link 60 has a rear end rotatably connected to the right knuckle arm 54.

The protrusion 86 is fixed to the center of the tie rod 50 in the left-right direction, and protrudes in the radial direction. The stopper 88 is
The protrusion 86 is fixed to the frame 16 so as to sandwich the protrusion 86 from both left and right sides, and the amount of displacement of the protrusion 86 in the left-right direction is limited by contact with the protrusion 86. The spring seat 90 is fixed to the center of the tie rod 56 in the left-right direction, and protrudes in the radial direction. A pair of extension coil springs 92 are arranged on both sides of the spring seat 90, couple the spring seat 90 and the frame 16, urge the spring seat 90 to the center in the left-right direction, and move the spring seat 90 right and left from the center. Acts as a resistance when displacing in the direction.

FIG. 4 is a configuration diagram of a four-wheel drive device of the speed sprayer 10. The rotational power of the engine 62 is transmitted to a distributor 68 via a transmission 64 whose switching ratio and rotational direction can be manually switched, and further via a propeller shaft 66.
The rotational power distributed to the front of the distributor 68 includes a rotation direction switching device 70 that includes a gear and switches the rotation direction by a manual rotation operation.
Is further transmitted to the front wheels 12 via the front differential 72 and the left and right front axles 74. Distributor
The rotational power distributed behind 68 is the propeller shaft 7
6, rear differential 78 and left and right rear axle 8
It is transmitted to the rear wheel 14 via 0.

When the speed sprayer 10 is operated in a normal state, the rotation direction switching device 70 is set to the normal rotation position and the front wheel
The rear wheel 12 and the rear wheel 14 are driven to rotate in the same direction, and the speed sprayer 10 moves forward or backward according to switching between forward and backward movements in the transmission 64, and turns according to the rotation direction of the steering wheel 28.

The operation of the embodiment will be described. Rotational operation of the steering wheel 28 (rotational operation exceeding the play of the steering wheel 28) is converted into hydraulic pressure in the all-hydraulic power steering device 30, and the steering cylinder 36
Extends and contracts relative to the reference length in relation to the turning direction of the steering wheel 28.

The pair of extension coil springs 92 try to hold the tie rod 56 at the center in the left-right direction via a spring seat 90, and the urging force of the pair of extension coil springs 92 applies the tie rod 56 and the right knuckle arm 54. The drag link 60 is transmitted to the rear wheel drag link 60 via the rear wheel drag link 60 and acts as a resistance to the displacement of the rear wheel drag link 60.

When the amount of operation of the steering wheel 28 to the left and right is small, such as when driving at high speed, the tie rod 50
Since the projection 86 does not contact the stopper 88, the tie rod 50 can be freely displaced in the left-right direction. As a result, the operating force of the rotational displacement of the rotating member 38 caused by the expansion and contraction of the steering cylinder 36 from the reference length is reduced.
Rotates around the connection point 43a while holding the shaft 42 in the guide hole 84, and the connection point 43b rotates largely. FIG.
Indicates the displacement of each part of the rotating member 38 when the steering wheel 28 is cut to the left. Connection point
The displacement of 43a is suppressed, and the connection point 43b and the shaft 42 rotate counterclockwise as A1 with the rotation of the rotating member 38, and move forward of the speed sprayer 10 as A2. As a result, while the front wheel drag link 58 is displaced in the front-rear direction, the rear wheel drag link 60 holds the front-rear position, and only the left and right front wheels 12 are steered.
The left and right rear wheels 14 maintain the straight traveling direction of the speed sprayer 10, and the speed sprayer 10 is driven by steering only the front wheels 12.

When the operation amount of the steering wheel 28 increases to a sufficiently large value as in the case of a small turn, etc.,
The protrusion 86 of the tie rod 50 contacts the stopper 88, and the tie rod 50 is prevented from being displaced in the left-right direction. In the subsequent operation amount range of the steering wheel 28, the drag link 58 for the front wheel does not move in the front-rear direction, whereas the drag link 60 for the rear wheel is allowed to be displaced in the front-rear direction due to the elastic deformation of the pair of extension coil springs 92. ing. Thus, the rotating member 38
Rotates around the connection point 43b while holding the shaft 42 in the guide hole 84, and the connection point 43a rotates largely. FIG.
Indicates the displacement of each part of the rotating member 38 when the steering wheel 28 is largely turned to the left. Connection point
The displacement of 43b is suppressed, and the connection point 43a and the shaft 42 rotate counterclockwise as B1 with the rotation of the rear overhang portion 40, respectively, and the speed sprayer 10 as B2.
Move to the back of. This allows drag links for front wheels
58 holds the front or rear end position in the front-rear direction, the rear wheel drag link 60 is displaced in the front-rear direction, the left and right front wheels 12 maintain the maximum steering angle, and the rear wheels 14 The steering is performed in the opposite phase, and the speed sprayer 10 is driven by the four-wheel steering in the opposite phase.

The illustrated speed sprayer 10 has four front wheels 12 and two rear wheels 14, each of which is two wheels.
There are two or more wheels on each side, and the present invention can be applied to a speed sprayer 10 having more than four wheels in total.

[0020]

According to the present invention, the rotating member is rotated in accordance with the operation amount of the steering wheel, and the front wheel steering link means and the rear wheel steering link means are respectively connected via the front wheel side connection point and the rear wheel side connection point. It is connected to one end side and the other end side of the rotating member, and transmits the rotational displacement of the front wheel side connection point and the rear wheel side connection point to the front wheel and the rear wheel, and the rear wheel is biased by the urging means in the straight running direction of the self-propelled vehicle. The rotating member is biased so as to face, and rotates around the rear wheel side connection point and the front wheel side connection point, respectively, in the range of small and large amounts of rotation operation. Therefore, the self-propelled vehicle is operated by steering only the front wheels in a range where the operation amount of the steering wheel is small at the time of high-speed driving, and in a range where the rotation operation amount of the steering wheel is large at the time of small turning at a low speed.
It is possible to drive the vehicle with anti-phase all-wheel steering, so that complicated switching operation can be omitted, and it is possible to achieve both small turning and traveling stability at the time of course change at the time of high-speed traveling.
In addition, since it is switching between antiphase all-wheel steering and front wheel steering,
The structure is simpler than a steering device that switches between anti-phase all-wheel steering and in-phase all-wheel steering.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a steering device of a speed sprayer.

FIG. 2 is a diagram showing displacement of each part of a rotating member when the steering wheel is cut to the left side;

FIG. 3 is a diagram showing displacement of each part of a rotating member when the steering wheel is largely turned to the left.

FIG. 4 is a configuration diagram of a four-wheel drive device of a speed sprayer.

FIG. 5 is a schematic side view of a speed sprayer.

[Explanation of symbols]

Reference Signs List 10 speed sprayer (self-propelled vehicle) 12 front wheel 14 rear wheel 28 steering wheel 38 rotating member 42 shaft (intermediate part) 43a connection point (rear wheel side connection point) 43b connection point (front wheel side connection point) 58 drag link for front wheel ( Front wheel steering link means) 60 Rear wheel drag link (Rear wheel steering link means) 84 Guide hole (Guiding means) 88 Stopper 92 Tension coil spring

Claims (1)

(57) [Scope of request for utility model registration] 1. The rear wheel is moved in the same direction or opposite to the steering of the front wheel.
Direction steering and the steering wheel
The steering angle of the front wheels by the
In a steering device of a self-propelled vehicle that is driven by steering
The rotation member (38) that is rotated in accordance with the operation amount of the steering wheel (28) is connected to the front wheel side connection point (43).
front wheel steering link means (58) for connecting to the one end side of the rotating member (38) via the second link (b) and transmitting the displacement of the front wheel side connection point (43b) to the front wheel (12); and a rear wheel side connection point. The rear wheel (14) is connected to the other end of the rotating member (38) via (43a) and changes the displacement of the rear wheel side connection point (43a).
Link means (60) for transmitting rear wheels, guide means (84) for guiding an intermediate portion (42) of the rotating member (38) in the front-rear direction of the self-propelled vehicle (10), and a rear wheel ( 1
4) urging means (92) for urging the self-propelled vehicle (10) in the straight traveling direction and a stop (88) for restricting the maximum value of the steering angle of the front wheels (12). Characteristic steering device for self-propelled vehicles.