JPH08301137A - Work vehicle - Google Patents

Abstract

PURPOSE: To provide a work vehicle in which assist force for a steering handle to be assist-operated by means of a power steering device can be properly changed and regulated according to a lateral inclination of a machine body. CONSTITUTION: A work vehicle is provided with an inclination detecting means 8, by which an angle of inclination of a machine body to the horizon in the lateral direction is detected, and an assist force controlling means 9, by which assist force for an electric power steering device 12 is lowered to be set on the basis of the detected result from the inclination detecting means 8 when the angle of inclination of the machine body to the horizon in the lateral direction is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a riding type rice transplanter,
The present invention relates to a work vehicle such as an agricultural tractor and a lawn mower, which is provided with a power steering device that assists a steering wheel.

[0002]

2. Description of the Related Art Conventionally, in this type of work vehicle, the assist force by the power steering device is set to be constant.

[0003]

However, in the conventional structure in which the assisting force is constantly applied at a constant level, for example, when the machine body is tilted to the left and right with respect to the horizontal relatively, There is a tendency to support the body with the steering wheel so that the posture during steering does not tilt,
When the steering handle is rotated a little to support it, if the steering handle operation is relatively light due to the power steering device, it is possible to maintain the posture of the operator while keeping the operator's body in the steering handle. The stability was low, and it was difficult to operate the steering wheel in that state.
Also, when the steering is operated with a relatively large assist force when returning the aircraft, the steering handle operation is lighter, so the steering handle operation position is closer to the steering neutral position. On the other hand, it becomes easy to overshoot unreasonably, and in order to recover the overshoot, the steering handle must be operated again to return to the straight running state. In such a work vehicle, it is necessary to maintain the straight running state as much as possible during the planting work, but the steering operation to escape from the tilted state when the aircraft leans to the left or right makes it impossible to run unfairly. There was a fear that it would be meandering.

The present invention has been made in view of the above circumstances, and provides a working vehicle in which the assisting force of a steering handle assisted by a power steering device can be appropriately changed and adjusted according to the tilt of the machine body to the left and right. For the purpose of provision.

[0005]

In order to achieve the above object, a work vehicle according to claim 1 of the present invention is provided with an inclination detecting means for detecting an inclination angle of a machine body with respect to a horizontal direction in the left-right direction, and Based on the detection result of the inclination detection means, an assist force control means for setting the assist force of the electric power steering device to be small when the inclination angle of the aircraft body with respect to the horizontal in the horizontal direction is increased is provided. Characteristic configuration.

A work vehicle according to a second aspect of the present invention is the work vehicle according to the first aspect, wherein the assist force control means controls the electric power steering when the inclination angle equal to or more than a preset value is maintained for a predetermined time or more. It is characterized in that the assisting force of the apparatus is reduced.
The operation and effect of this characteristic configuration are as follows.

[0007]

That is, according to the first aspect of the invention, the assist force of the electric power steering device is set to be small when the inclination angle of the machine body with respect to the horizontal in the horizontal direction is large. It will be automatically set so that steering at a large angle cannot be performed even if the steering handle is operated to eliminate the tilt of the aircraft, and the neutral position is used to return the steering handle to the neutral position. It is possible to prevent the steering wheel from being operated in a more overshooting state. Even when the operator supports the body with the steering wheel when the machine body is tilted, the operation of the steering wheel is heavy on the machine body due to the left and right tilts, so that the operator can sufficiently support the body.

According to the structure of claim 2, in addition to the operation of claim 1, the assist force control means of the electric power steering device, when the tilt angle equal to or more than the set value is maintained for a predetermined time or more. Since it is configured to reduce the assist force, it is possible to maintain the normal assist force for temporary leaning of the aircraft.By changing the assisting force each time the aircraft leans, the steering wheel can be operated. It is possible to prevent the driver from feeling uncomfortable due to frequent changes in force.

[0009]

Therefore, according to the first aspect of the invention, since the assisting force by the electric power steering device in the steering wheel operation is appropriately set in accordance with the tilted state of the body left and right, the left and right sides of the body As a result, the driver can operate in a stable posture with respect to the inclination of the vehicle, and it is possible to avoid a large meandering run by the driver unduly steering too much. .

According to the second aspect of the present invention, since the assisting force of the electric power steering device is not changed with respect to a mere temporary tilt of the machine body, every time the machine body is tilted left and right. It is possible to solve the problem that the assist force is changed and to make it easier to operate without making the driver feel uncomfortable.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a riding-type rice transplanter for six-row planting as an example of a work vehicle. In this riding type rice transplanter, an engine 4, a boarding operation unit 5, a mission case 6, a seedling planting device 7, etc. are mounted on a body 3 supported by a pair of left and right front wheels 1, 1 and rear wheels 2, 2 so as to be able to travel. It is equipped with and configured.

As shown in FIGS. 1 to 3, a tilt angle sensor 8 for detecting the tilt angle of the machine body 3 in the left-right direction with respect to the horizontal is installed at a position approximately in the center of the machine body 3 in the front-rear and left-right directions. ing. The detection signal of the tilt angle sensor 8 is input to the control device 9 as an assist force control means provided in the machine body 3. Further, as shown in FIG. 2, the steering wheel 10 provided in the boarding operation unit 5 has a power steering device 1 that is assisted by an electric motor 11.
2 are linked to each other. When the time when the inclination angle α detected by the inclination angle sensor 8 with respect to the horizontal is larger than the preset inclination angle β with respect to the horizontal, the control device 9 continues for a set time t (for example, 1 second) or more. The electric motor 1 sends a drive control signal for lowering the drive torque of the electric motor 11 than usual so that the steering handle 10 is operated with the assist force reduced from the normal assist force.
Output to 1. Specifically, for example, the electric motor 11 may be configured by a pulse driving motor, and a pulse signal for driving the electric motor 11 may be controlled by a pulse width modulation signal.

According to the above configuration, in the control device 9, the machine body inclination angle α becomes larger than the set angle β based on the detection result of the inclination angle sensor 8 in the horizontal direction of the machine body 3 with respect to the horizontal direction. When the steeply tilted posture continues for a predetermined time t or more, a large amount of artificial operation force of the steering handle 10 is required. Therefore, if the tilt of the body 3 in the left-right direction is larger than a predetermined value, a heavy steering operation is required. As a result, the operator can apply a large amount of load to the steering handle when the vehicle body 3 leans greatly to the left and right. Since it will also be used as a member that supports the vehicle, it is possible for the operator to operate in a stable posture.

Next, the seedling planting device 7 will be described. As shown in FIGS. 1, 4, 5, and 6, the seedling planting device 7
Is supported on the rear part of the machine body 1 by a hydraulic cylinder 14 via a four-link mechanism 13 so as to be able to move up and down, and by an operation of an electric rolling motor 15 so as to be capable of swinging left and right around a longitudinal axis. Then, the seedling planting device 7 includes a seedling stand 16 and a seedling stand 1 on which seedlings for planting are placed and reciprocally moved laterally.
It is composed of a planting mechanism 17 for taking out one seedling from the lower end of 6 and planting it in the field, a leveling float 18 that slides on a mud surface, and the like. A line drawing marker 19 for drawing a line groove on the mud surface, which serves as a running index in the case of, is provided so as to be able to move in and out. The planting mechanism 17 is provided in the planting claw support cases 22 and 22 that rotate relative to both ends of a rotating case 21 that is rotationally driven around a horizontal axis with respect to the planting transmission case 20, based on set characteristics. The planting claws 23, 23 are used to plant seedlings.

As shown in FIGS. 5 and 6, the left and right planted transmission cases 2 are provided at the front of the respective planted transmission cases 20.
A float fulcrum pipe 24 that is laid horizontally over 0 is pivotally connected so as to be rotatable around its axis P1. On the float fulcrum pipe 24, a swing arm 25 that integrally rotates with the float fulcrum pipe 24 is extended in parallel rearward. At the swing end of each swing arm 25, the leveling float 18 is provided with a shaft P through a support shaft 26.
It is connected so that it can swing up and down around 2. An operation lever 27 extending toward the machine body 3 is integrally and rotatably connected to and fixed to the float fulcrum pipe 24.
A locking plate 29 that locks and holds the operation lever 27 at an arbitrary position by engaging the operation lever 27 on the support frame 28.
Are connected and fixed via a support plate 30. That is, by operating the operation lever 27 around the axis P1 of the float fulcrum pipe 22 and engagingly retaining the retaining plate 29 at an arbitrary position, the leveling float 18 of the grounded float 18 with respect to the planted transmission case 20 is retained. The relative height can be adjusted, and the planting depth of seedlings can be changed according to the hardness of mud in the field.

As shown in FIG. 6, in the upper front portion of the leveling float 18 located in the center, the vertical swing displacement of the leveling float 18 in the center due to the fluctuation of the ground pressure is linked to the link mechanism 31.
A float sensor 32 of the potentiometer type is provided for detection via the. The float sensor 32 is supported by a bracket 34 that is pivotally supported at the ends of a pair of upper and lower links 33 that are pivotally supported so as to be vertically swingable with respect to the support plate 30. Although not described in detail, with this support structure, the float sensor 32 converts the vertical swing displacement of the leveling float 18 located in the center into a voltage level, and outputs the voltage level to the control device 9 as float displacement information. Control device 9
On the basis of the float displacement information from the float sensor 32, the reference voltage level of the float sensor 32 indicating the reference attitude of the ground leveling float 18 in the center and the voltage level (float displacement information) output from the float sensor 32 match. As described above, the operation of the electromagnetic control valve for the hydraulic cylinder 14 is controlled to raise and lower the seedling planting device 7.

Further, the control device 9 includes the operation lever 27.
The float sensor 32 to the sensitivity target value artificially set by
The control program is provided with means for automatically adjusting the sensing sensitivity of. Then, in order to automatically adjust it, the first grounding body 37A that detects a change in the mud surface level by converting the change in the mud surface level into a vertical swing displacement by following the ground contact with the surface of the field mud.
And a second grounding body 37B that changes the level of the bottom surface of the groove trace into a vertical swing displacement by following the ground contact with the bottom surface of the groove trace formed after passing the mud surface of the leveling float 18 located on the left and right, and these grounding bodies. A pair of left and right groove trace depth detecting means 37 is configured by a rotation sensor 37C which is a potentiometer that detects the relative swing displacement amount of 37A and 37B and outputs a voltage level according to the relative swing displacement amount. There is. As shown in FIGS. 4 and 5, the operation shaft 37C of the rotation sensor is pivotally operated by the vertical swing displacement of the first grounding body 37A, and the rotation sensor 37C is moved by the vertical swinging displacement of the second grounding body 37B. The sensor body is rotatably operated, and accordingly, the rotation sensor 37C is operated by the first grounding body 3
The amount of relative swing displacement between 7A and the second grounding body 37B can be detected. The detection information of the relative swing displacement amount detected by the rotation sensor 37C is output to the control device 9 as groove trace depth information. The control device 9 sequentially inputs the groove trace depth information and sequentially calculates the moving average of the groove trace depth information, and also compares the latest moving average with the groove trace depth information (latest moving average). The mud hardness is detected by comparing with the preset target groove trace depth (target voltage level) as a value,
The sensitivity target value (reference voltage level) of the float sensor 32 is automatically selected according to the mud hardness and the float sensor 32 is selected.
The sensing sensitivity of is automatically adjusted.

As shown in FIGS. 7 and 8, the first grounding body 3
The 7A and the second grounding body 37B are provided with a pair of left and right grooves 38 that extend along the front-rear direction and that are open in order to make it less susceptible to resistance due to mud or water. As a result, the contact areas of the first grounding body 37A and the second grounding body 37B with respect to the mud surface can be increased, so
Unjust subsidence of 37B itself can be suppressed as much as possible. Further, the first grounding body 37A and the second grounding body 37B are provided with a small stepping motor 39 outward from the lower left and right side surfaces thereof.
The wing-shaped plate body 40 that can be driven to move in and out is stored and installed. This winged plate body 40 is provided in the first grounding body 37 in a recess H such as a hole or groove formed by a lug of a wheel in a field.
A or the second grounding body 37B falls, and the rotation sensor 37
When the detected value of C suddenly changes, the small stepping motor 39 driven by the drive signal from the control device 9 that has judged the change causes the small stepping motor 39 to perform a projecting operation to increase the installation area and prevent an undesired drop. Suppress. Based on the detection information of the rotation sensor 37C, it is determined that the depression into the recess H has been resolved after a certain amount of time has passed.
When the determination is made in 5, the small stepping motor 39 is driven so as to house the wing-shaped plate members 40 of the first grounding body 37A and the second grounding body 37B. The small stepping motor 39 and the wing plate 40 are linked by a gear mechanism.

[Other Embodiments] The assist force may be reduced in proportion to the left and right body tilt angles.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is an overall side view showing a riding type rice transplanter.

FIG. 2 is an explanatory diagram showing an outline of an electric power steering device and the like.

FIG. 3 is a front view showing a vehicle body and a sensor of a riding-type rice transplanter that is inclined to the horizontal on the left and right.

FIG. 4 is a plan view showing a lower portion of the seedling planting device.

FIG. 5 is a vertical sectional side view showing the lower part of the seedling planting device.

FIG. 6 is a vertical cross-sectional side view showing the front part of the leveling float in the center, the float sensor, and the like.

FIG. 7 is a plan view showing an installation sensor of a groove depth detecting means and a recess in a field.

FIG. 8 is a vertical cross-sectional rear view showing the installation sensor of the groove depth detecting means and the concave portion of the field.

[Explanation of symbols]

 3 Aircraft 8 Inclination detection means 9 Assist force control means 12 Electric power steering device

Claims (2)

[Claims] 1. A tilt detecting means (8) for detecting a tilt angle of a machine body (3) with respect to a horizontal direction is provided, and the machine body (3) is based on a detection result of the tilt detecting means (8). A work vehicle provided with an assist force control means (9) for setting the assist force of the electric power steering device (12) to be small when the inclination angle of the electric power steering device with respect to the horizontal is increased. 2. The assist force control means (9) is configured to decrease the assist force of the electric power steering device (12) when an inclination angle equal to or larger than a set value is maintained for a predetermined time or longer. The work vehicle according to claim 1.