JPH0236341Y2 - - Google Patents

Description

[Detailed description of the invention] This invention switches the valve in conjunction with the vertical displacement of the sensing float so that the planting depth can be automatically maintained constant or almost constant regardless of changes in the depth of the discharge plate. This relates to a running device for a rice transplanter, which is equipped with a wheel elevation control mechanism for operating a hydraulic cylinder and controlling the running wheels in a direction opposite to the direction of displacement of the sensing float to keep the attitude of the machine body on the ground constant or substantially constant. It is.

Conventionally, a three-position switching type valve having a wheel up position and a wheel down position on both sides of a neutral position has been used as a valve used for controlling the wheel up/down.

However, in a typical three-position switching valve, since the switching stroke from the neutral position to the wheel raising or lowering position is large, a large amount of displacement of the sensing float is required when the lift control is performed. Therefore, in order for the sensing flow, which moves up and down based on changes in ground pressure against the soft mud on the field surface, to be displaced by the amount corresponding to the stroke to switch the valve, the body must move up and down to a certain degree with respect to the mud surface. , it became less stable.

In other words, in this wheel elevation control mechanism,
Since the sensing float is configured to detect pressure changes from the soft mud on the surface of the field and switch the valve, the shorter the switching load and stroke of the valve, the more stable the lifting and lowering control of the wheels can be performed.

The present invention focuses on this point and aims to provide a traveling device for a rice transplanter that can perform stable wheel elevation control with a small valve switching load.

For this reason, in the present invention, a rice transplanter's traveling device is configured to move the traveling wheels up and down in the opposite direction to the up and down movement of the sensing float by detecting the up and down movement of the sensing float and changing the rotary valve to expand and contract the hydraulic cylinder. , the width along the spool rotation direction of each of the pump port and tank port formed in the valve body is the width in the rotation direction of the spool of the pair of walls that partition the through hole provided in the rotation spool of the rotary valve and the pair of recesses. In addition to making it smaller, when the machine lowering operation port is communicated with the tank port during switching between the lifting stop state and the raising/lowering state, the communication opening of the pump port with respect to the fuselage raising operation port and the pump port with respect to the tank port are determined. It is characterized in that the communication opening degree is increased/decreased contrary to the rotation of the spool, and the driving wheels are linked in order to raise and lower the traveling wheels.

According to the above configuration, in the first state, the traveling wheels are raised or lowered by supplying pressure oil to each of the cylinder oil chambers while rotating the spool in a large range, and in the first state, by rotating the spool in a small range and adjusting the pressure balance. The first state can be used mainly for manual operation, and the second state can be used for automatic control of raising and lowering the wheels. Since this can be done with a stroke, the sensing load of the sensing float can be reduced and stable wheel elevation control with good sensitivity can be performed.

Moreover, when controlling the wheels to go up and down by operating the valves using sensing floats, the pump ports are not blocked during the changeover between raising and lowering the wheels, so there is no pressure build-up in the circuit, and the valves switch smoothly and stably. This is effective for performing wheel elevation control.

Hereinafter, embodiments of the present invention will be described based on the drawings.

As shown in Figures 1 and 2, a driving unit including an engine E and a transmission case M is provided at the front of the machine, and a seedling stand 1 and a planting claw 2 are provided at the rear of the machine. A planting device 3 is provided, and a pair of left and right running wheels 4 that touch the ground on the discharge plate are provided,
A sensing float 5 for lifting and lowering control that also serves as a support for sliding on a mud surface is provided, and a control handle rod 6 is provided on the back of the seedling planting device 3 to constitute a walking rice transplanter. .

As shown in Fig. 1, Fig. 2, and Fig. 6,
To configure the left-right swinging type shift lever 7 for the traveling gear transmission housed in the transmission case M, a cylindrical shift rod is attached to the lateral side of a cylindrical body 9 that fits around the support shaft 8. At the same time, a grip 7b is attached to the upper end of the shift rod 7a so as to be freely insertable and removable, and a swing arm 10 linked to the shift member for shifting is attached to the lower end of the cylindrical body 9. The vehicle is configured so that traveling speeds can be changed by operating the lever 7 from a neutral gear position N, a reverse position R, a first forward gear position F ₁ , and a second forward gear position F ₂ . In addition, the recoil starter operation wire 11
Insert the inside of the gear change rod 7a and tighten the grip 7b.
The engine E can then be started by pulling the grip 7b. However, the gear shift lever 7 is provided so as to be in a posture along the longitudinal direction of the aircraft body at the neutral position N, so that it is easy to pull the grip 7b toward the rear when starting the engine.

As shown in FIGS. 1 to 5 A, B, C, and D, the transmission cases 12, 12, which also serve as support frames for the traveling wheels 4, 4, are pivoted vertically around the horizontal axis X. The seedling planting device 3 is supported so that the entire machine body can be raised and lowered as the wheels go up and down, and a double-acting hydraulic cylinder 13 for lifting and lowering that extends and contracts along the longitudinal direction of the machine body is attached only at its front end. The relay arm 1 is provided in a cantilevered manner and supported by the relay arm 1.
The longitudinal center portion of the arm 14 is pivoted to the rear end portion of a piston rod 13B that protrudes from the cylinder case 13A toward the rear of the fuselage body so as to be swingable about the vertical axis P. Arms 12A erected at the bases of both transmission cases 12, 12,
12A through push/pull rods 15, 15, in order to maintain a constant planting depth regardless of changes in plowing depth, or when driving on headlands and roads. In order to levitate the machine body above the ground, the wheels 4, 4 are configured to be able to be raised and lowered, and the left and right wheels 4, 4 are raised and lowered in a reverse manner according to the unevenness of the tiller, thereby suppressing the left and right tilting of the machine body. be.

A rotary valve V for controlling the hydraulic cylinder 13 is housed in the front end portion of the cylinder case 13A. In other words, the oil passage forming hole 16 that communicates the hydraulic cylinder with the body raising operation side oil chamber _U1 of 13 and the body raising operation port _U0 of the rotary valve V,
An oil passage formed in the front end side of the cylinder case 13A and communicating between the body lowering operation side oil chamber _D1 of the hydraulic cylinder 13 and the body lowering operation port _D0 of the rotary valve V is connected to the front end side of the cylinder case 13A and Oil passage forming holes 1 formed in each rear end side part
7a, 17b and their holes 17a, 17b
It also consists of a pipe 18 connecting the hydraulic pump P and the pump port of the rotary valve V.
The oil passage forming hole ₁₉ connecting the tank port T0 of the rotary valve V and the oil passage forming hole 19 connecting the tank port T0 of the rotary valve V to the oil passage forming hole 19 connecting the tank port _T0 of the rotary valve V to the oil passage forming hole 19 connecting the tank port T0 of the rotary valve V to It is formed on the front end side.

When the rotary valve V is configured, the pump port P ₀ and the tank port T _{0 are connected} when the lift is stopped.
and the through hole 21 that communicates with the pump port P ₀ and _the tank port T ₀ in order to switch between the ascending state and _the descending state. A pair of connecting recesses 22, 22 are formed in the rotary spool 24, respectively. Also, a pair of walls 23 that partition the through hole 21 and the pair of recesses 22, 22,
The width along the spool rotational direction of each of 23 is formed to be smaller than the width along the spool rotational direction of each of the pump port P ₀ and the tank port T ₀ , so that during switching between the lifting stop state and the rising state, With the aircraft lowering operation port D ₀ communicating with the tank port T ₀ , the communication opening degree of the pump port P ₀ with respect to the aircraft raising operation port U ₀ and the communication opening degree of the pump port P ₀ with respect to the tank port T ₀ , Spool 2
4 is reversely increased and decreased as the number 4 rotates, so that the aircraft, which is biased downward by its own weight, can be raised and lowered.

In other words, to raise or lower the aircraft,
A first state in which the wheels 4 are lowered or raised by supplying pressure oil to each of the cylinder oil chambers U ₁ and D ₁ while rotating the rotary spool 24 over a large range; It is configured such that it can be performed in a second state by pressure balance while rotating within a range, and in the first state,
It is mainly used for manual elevating and lowering operations, and the second state is used during elevating and lowering control, which will be described later.

The sensing float 5 for controlling the elevation is pivoted to the body so as to be able to swing vertically around the horizontal axis Y on the rear end side, and the front end of the sensing float 5 is connected to the operating lever 24A of the revised spool 24. Link mechanism 25
A spring 26 that operates the sensing float 5 in the downward direction is provided to act on the relay swing link 25A in the link mechanism 25, thereby setting the seedling planting depth. In order to maintain this range, the rotary spool 24 is configured to be automatically operated by the vertical movement of the sensing float 5.

In other words, when the sensing float 5 swings higher than the set range of swing, the rotary valve V is switched to the lower side of the aircraft, and when it swings lower than the set range, the rotary valve V is switched to the lower side of the aircraft. If the seedling planting depth suddenly changes over a large range, the rotary valve V may be operated to the above-mentioned first state, but during normal control, the rotary valve V may be operated to the above-mentioned second state. will be operated on.

In addition, 27 in the figure is a locking arm for manual operation to lock the relay swing link 25A to the rising side of the seedling planting device, and is linked by a wire to a lift lever 28 attached to the handle bar 6. .

Both oil chambers U ₁ and D ₁ in the hydraulic cylinder 13
rod-shaped parts 29a, 29a for pushing the pair of valve bodies 29, 29 for opening and closing the communication toward the opening side while being elastically biased toward the closing side by the spring 30 located between them; The oil chamber U ₁ , D ₁
The valve bodies 29, 29 are installed in the cylinder piston 13C in a state of protruding to the side, and when the hydraulic cylinder 13 reaches or near the stroke end on the ascending side and descending side, the valve bodies 29, 29 are attached to the cylinder case 1.
It is configured so that the pressure in the circuit does not increase even when the cylinder 13 reaches the stroke end by pushing the cylinder 13 open at 3A.

More specifically, in each of the pair of valve bodies 29, 29, the one adjacent to the pressure oil supply side oil chamber is opened by pressure oil, and the one adjacent to the oil discharge side oil chamber is opened by the cylinder case. It is pushed open by 13A to communicate both oil chambers U ₁ and D ₁ .

Next, another example will be described.

In FIG. 7, the cylinder piston 13C is divided into a pair of left-right symmetric piston parts 13a and 13b, and valve bodies 29 and 29 are assembled into the cylinder piston 13C. However, 32 in the figure is O for sealing.
The ring 33 is a positioning knob pin.

Furthermore, in the embodiment, even when the cylinder 13 reaches the downward stroke end, both oil chambers U ₁ ,
Although an example is shown in which the oil chambers U 1 and D ₁ are communicated with each other, only when the upward stroke end is reached, both oil chambers U ₁ ,
All you have to do is connect _D1 . In other words, when the rotary valve V is configured to be operated up and down only by changing the opening degree in a reverse manner, it is not necessary to communicate the two oil chambers U ₁ and D ₁ when the downward stroke end is reached. However, when the rotary valve V is configured as described in the embodiment, both oil chambers are closed even when the lower stroke end is reached.
Of course, it is better to make U ₁ and D ₁ communicate.

Furthermore, an operating member may be attached to the cylinder case 13A to push open the valve bodies 29, 29.

Further, instead of the link mechanism 25, a link mechanism using a wire may be used.

[Brief explanation of the drawing]

The drawings show an embodiment of the traveling device for a rice transplanter according to the present invention, in which FIG. 1 is a side view of the walking rice transplanter, FIG. 2 is a schematic plan view of the machine, and FIG. 3 is a schematic side view of the elevation control device. , FIG. 4 is a longitudinal side view of the hydraulic cylinder and rotary valve, FIGS. The figure is a longitudinal sectional side view showing another embodiment. 4... Running wheel, 5... Sensing float, 13...
... Hydraulic cylinder, 21 ... Through hole, 22 ... Recess, 23 ... Wall, 24 ... Rotating spool, D ₀ ...
...Aircraft lowering operation port, U ₀ ... Aircraft raising operation port, P ₀ ... Pump port, T ₀ ... Tank port, V... Rotary valve.

Claims (1)

[Scope of utility model registration request] A traveling device for a rice transplanter configured to detect the vertical movement of a sensing float 5, change a rotary valve V to expand and contract a hydraulic cylinder 13, and thereby vertically control a running wheel 4 in a direction opposite to the vertical movement of the sensing float 5. In this case, the width in the spool rotation direction of the pair of walls 23 that partition the through hole 21 and the recess 22 provided in the rotary spool 24 of the rotary valve V is determined by the width of the pump port P ₀ and the tank port T ₀ formed in the valve body. The width is smaller than the width along the rotational direction of each spool, and the machine lowering operation port D ₀ is communicated with the tank port T ₀ during switching between the lifting stop state and the lifting operation state.
Pump port P ₀ for aircraft lift operation port U ₀
and the communication opening of the pump port P ₀ with respect to the tank port T ₀ are increased/decreased contradictoryly as the spool 24 rotates to control the vertical elevation of the running wheels 4. Device.