JPH10136723A - Lowering speed adjustment mechanism for transplanter - Google Patents

Abstract

(57) [Problem] To provide a descent speed control device for reducing the descent speed of a working machine, which has a structure in which the elevating speed of the working machine is not reduced more than necessary. SOLUTION: When the hydraulic cylinder 18 controlled by a control valve 16 of a working machine 9 connected to a traveling machine body 6 so as to be able to ascend and descend via a link mechanism 8, a vertical swing provided below the working machine 9. The control valve 16 for decreasing the lowering speed of the work machine when the float 13 can be grounded is switched from the maximum throttle state to the open state sequentially by switching the control valve 16 from the neutral position to the upward or downward direction of the work machine 9. The structure is to be shifted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lowering operation of a transplanting machine such as a rice transplanter for controlling the lowering speed of the working machine after the float touches down when the working machine is lowered from a raised position. It relates to a speed adjusting mechanism.

[0002]

2. Description of the Related Art Conventionally, as a speed control device for controlling a descending speed of a float of a working machine in a transplanting machine such as a riding rice transplanter after the landing of the work machine, a working machine as disclosed in JP-B-63-47409 has been proposed. The throttle that slows down the hydraulic cylinder, which moves the machine up and down via the lifting link,
It is known that the hydraulic cylinder is formed in a control valve for driving the hydraulic cylinder, the throttle section is operated after the float is grounded, the contraction of the hydraulic cylinder is slowed, and the descent speed of the working machine is gradually reduced. I have.

[0003]

On the other hand, in a relatively hard field or the like, the working machine may be planted and run while the front end of the float is inclined upward and the float is pressed against the field. When the work machine is lowered, there is a drawback that the work machine descends at the slowest speed due to the operation of the squeezing section, and the followability of the work machine to the field may deteriorate.

[0004]

In order to solve the above-mentioned problems, a lowering speed adjusting mechanism for a transplanter according to the present invention comprises a work mechanism 9 for transplantation provided with a float 13a capable of vertically swinging below a link mechanism. 8 to the traveling body 6 so as to be able to move up and down freely,
A hydraulic cylinder 18 is provided between the link mechanism 8 and the traveling machine body 6 to drive the working machine 9 up and down, and a control valve 16 for controlling the hydraulic cylinder 18 to control the lifting and lowering of the working machine 9 is provided. When the float 13 a is grounded, the working machine 9 is connected to a hydraulic circuit 20 between the hydraulic cylinder 16 and the hydraulic cylinder 18.
A control valve 17 for reducing the descending speed of the work machine is provided, and the control valve 16 is configured such that the float 13a is grounded and the control valve 16 for holding the transplant height of the working machine 9 is in a maximum throttle state when the neutral position is attained. The first feature of the machine is that the control valve 17 has a structure in which the control valve 16 is switched from the neutral position to the ascending or descending direction of the work machine 9 to sequentially shift from the maximum throttle state to the open state. .

The control valve 17 is provided with two flow passages 44a, 4 of which either one is selectively opened by operation of the control valve 17 in the ascending or descending direction from the maximum throttle state.
The second feature is that 4b is formed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a riding rice transplanter, which is a transplanter, will be described in detail below. FIG.
As shown in FIG. 1, a traveling body 6 is formed by supporting a body frame 2 on which an engine 1 and the like are mounted on front and rear wheels 3 and 4, and an upper link is provided behind a driver seat 7 provided on the traveling body 6. A working machine 9 for planting is connected to be able to move up and down via an elevating link 8 composed of a lower link 8a and a lower link 8b. At this time, the working machine 9 is located
1 is inclined, and a support link 12 is provided below.
A plurality of floats 13 are provided in the left and right direction so as to be able to swing up and down via the.

[0007] The riding rice transplanter comprises a plurality of floats 1
3, the traveling machine 6 is moved in a state where the working machine 9 is lowered to the planting posture A substantially parallel to the field scene with the contact surface 15 which is substantially the entire lower surface in contact with the field scene, and the seedlings are mounted. The planting device 14 provided in the working machine 9 corresponding to the seedling take-out opening of the stand 11 is driven by a driving force transmitted from the traveling machine body 6 via a clutch (not shown) for driving the working machine 9. By reciprocating vertically, the traveling body 6
With the traveling, the seedlings are scraped from the seedling mounting table 11 and planted in a field.

On the other hand, between the elevating link 8 and the traveling machine body 6, a hydraulic cylinder 18 (details will be described later) whose operation is controlled by a control valve 16 (details will be described later) and an adjustment valve 17 (details will be described later) is a hydraulic valve. The lifting and lowering link 8 swings up and down due to the expansion and contraction of the hydraulic cylinder 18, and the working machine 9 moves up and down. In the above-described planting work state (planting posture A), the float 1
Automatic swing control according to the field condition is performed by the swing of 3, and the posture is controlled so that the planting depth of seedling planting is constant.

Next, the structure of the control valve 16 will be described. The control valve 16 has an input connected to the output side of a hydraulic pump 19 driven by the engine 1 as shown in a hydraulic circuit 20 for lifting and lowering control of the work machine 9 shown in FIG. As shown in FIG. 3, the flow of the hydraulic oil is controlled by rotating an operation shaft 16 a protruding from the control valve 16 (housing). This is a rotary valve that is controlled to drive the hydraulic cylinder 18 in a switching manner.

The control valve 16 (operation shaft 16a) is provided with an operation lever 22 provided on the driver's seat 7 side which can swing back and forth along a lever guide 21 shown in FIG.
5 (see FIG. 5), as shown in FIGS. 5 and 6, the operating lever 22 is connected not only to the control valve 16 but also to the clutch of the working machine 9 as shown in FIG. (Details are not shown), and the operation of the control valve 16 (elevation and lowering of the working machine 9) and the turning on and off of the power to the working machine 9 can be performed by the swing operation of one operating lever 22. It is configured as follows.

That is, the operation lever 22 is moved to the lever guide 21
Is switched to the a position, the c position, or the b position, the operation shaft 16a is connected to the X1, X2 or X3 via the switching arm 23a constituting the connection link mechanism 23.
And the control valve 16 is turned by turning to X1.
Is switched to send pressurized oil to the hydraulic cylinder 18, the hydraulic cylinder 18 extends, the work implement 9 rises, and X2
The position (height) of the working machine 9 is fixed by the rotation to
By turning to X3, the control valve 16 moves the hydraulic cylinder 1
The pressure is switched so that the pressurized oil in the inside 8 can be discharged, and the hydraulic cylinder 18 contracts by its own weight of the working machine 9 and the like, and the working machine 9 descends.

At this time, when the operating lever 22 is switched to the position b and the working machine 9 is lowered to the above-described planting position A, the operating shaft 16a is rotated in the range of Y1, and the hydraulic oil to be discharged from the hydraulic cylinder 18 is released. Hydraulic cylinder 18
The pressure oil to be sent to the
The control valve 16 is switched to an underlap state (neutral posture) in which the work machine 9 does not expand and contract, and the working machine 9 is supported on the ground in the planting posture A on the field scene. Then, the operation lever 22 is moved to d.
By switching to the position, the control valve 16 remains in the underlap state (the working machine 9 remains in the planting posture A).
When the clutch is engaged, the work machine 9 operates, and the riding rice transplanter (work machine 9) performs the planting operation.

On the other hand, as shown in FIGS. 5 and 6, one end of a sensing arm 24 whose intermediate portion is rotatably supported on the body frame 2 side is connected to the switching arm 23a via a rod 26.
The other end is connected to the other side, and the other end of the float 13 (the center float in the present embodiment) of the plurality of floats 13 via the sensing rod 27 is vertically swung by sensing the ground pressure. Is connected to the support link 12 side of the sensing float 13a that typically senses At this time, the sensing rod 27 is connected to the sensing float 13a.
Move in the β direction by swinging in the a direction, and move in the α direction by swinging in the b direction.

With the above structure, the planting posture A of the working machine 9
When the work machine 9 (float 13) changes its posture from
As described later, the control valve 16 corresponds to a contact state (vertical swing operation) by sensing the contact pressure of the sensing float 13a.
Arm 2 that connects the sensor float 13a
4, 23a, the rods 26, 27, etc., the sensing link mechanism 28 is operated, and Y2 or X3 from Y1 corresponding to the operation of the sensing link mechanism 28 of the operating shaft 16a connected to the sensing link mechanism 28 is operated. The control valve 16 is switched by turning to part Y3, and the elevation of the working machine 9 is automatically controlled so that the planting depth, that is, the planting posture A is constant.

At this time, as shown in FIG. 3, the control valve 16 controls the X1, X2 in the rotation range of the operation shaft 16a.
2 and X3 are manually controlled ranges X, Y1, Y2,
Y3 is the automatic control range Y, and the sensing link mechanism 2
8 is configured so that when the operation lever 22 is switched to the b or d position, the control valve 16 rotates only within the automatic control range Y and does not rotate into the manual control range X. I have.

Next, the structure of the control valve 17 will be described. As shown in FIGS. 7 (a) and 7 (b), the control valve 17 has a main path 3 formed in the left-right direction in FIG.
1 is a rotary valve provided with a rotary valve 32 rotatably inserted into an input path 1 and an input path 33 and an output path 34 communicating with (spatially connected to) the main path 31 and having an output. Communicating with the path 34 and the main path 31;
Further, a check path 36 and a bypass path 37 which are also in communication with each other are also formed. As shown in FIGS. 5 to 8, the input path 33 is connected to the output of the control valve 16, and the output path 34 is connected to the hydraulic cylinder 18. Each is connected via a connector 38.

At this time, the main route 3 on the check route 36
The main path 31 is connected by a spring 39 to a portion connected to the main path 31.
A check ball 41 biased to the side is provided,
The pressure oil flowing from the output path 34 (the hydraulic cylinder 18 side) is restricted from flowing into the main path 31 through the check path 36, and the pressure oil flowing from the input path 33 into the main path 31 is The check valve 41 is pressed against the urging force to open the connecting portion by pushing the check ball 41 and can flow into the output path 34 through the check path 36. The bypass path 37 has a communication path 42 that is narrower than the main path 31 and the output path 34, and the pressure oil passing through the bypass path 37 is restricted by the communication path 42 to the output path 34 or the input path 33. Sent.

On the other hand, the rotary valve 32 has a shape in which a substantially cylindrical valve 44 is fitted to the adjusting shaft 43 protruding from the adjusting valve 17 while being rotatably shielded by the ring 45 on the main path 31. The valve 44 is provided with a concave flow passage 44a and a flow passage 44b formed in a part of the peripheral surface and formed by opposing flats reaching the ends, as shown in FIG. 7 (a). By rotating the rotary valve 32 (adjustment shaft 43), the flow path 44a of the valve 44 or the flow path 4
4b communicates with the output path 34 in opposition, the main path 31 and the output path 34 are opened, and pressure oil flows between the input path 33 and the output path 34 via the flow path 44a or the flow path 44b and the main path 31. It is configured to be able to flow directly.

The flow passages 44a and 44b are
As shown in FIGS. 7B and 9B, the rotation of the rotary valve 32 causes the input path 33 and the output path 34 (the main path 3).
1) is formed in the valve 44 such that the valve 44 is at a limit position where the output path 34 and the main path 31 do not communicate with each other when the valve 1 is completely closed by the valve 44 (the maximum throttle state of the control valve 17). The rotary valve 32 (valve 44) is connected to the input path 33.
And the output path 34 are completely closed.
Is rotated right or left, so that the flow path 44a
Alternatively, the main path 31 and the output path 34 are configured to open (communicate) via the flow path 44b.

With the above structure, the input path 33 and the output path 34 do not communicate with each other through both the flow path 44a and the flow path 44b. The relative angle between the flow path 44a or the flow path 44b and the output path 34 changes depending on the rotation angle of the rotary valve 32, and the flow path 44a or the flow path 44b
Is regulated. That is, the adjustment valve 17 is sequentially rotated from the maximum throttle state to the open state by either the flow path 44a or the flow path 44b by the rotation of the rotary valve 32, and has a rotary structure capable of adjusting the pressure oil. ing.

On the other hand, as shown in FIGS. 5 to 7, an adjusting arm 46 having a substantially triangular shape in a side view (FIGS. 5 and 6) is provided at an end of the rotary valve 32 so as to rotate integrally with the rotary valve 32. And two connecting portions 46b, 4 located at the other two vertices of the adjusting arm.
One connecting portion 46b of 6c is connected to the rod 26 via a connecting rod 47.

At this time, the connecting portion 46b between the adjusting arm 46 and the connecting rod 47 is located below the valve mounting portion 46a. When the connecting rod 47 moves in the α or β direction, the adjusting arm 46 also moves in the α or β direction. Since the rotary valve 32 (valve 44) is configured to rotate in the α or β direction as shown in FIG.
8 operates, the connecting rod 47 follows the operation of the rod 26.
The throttle operation of the control valve 16 is automatically controlled via the control valve.

The adjusting arm 46 and the sensing link mechanism 28
When the work machine 9 is lifted and the front end of the float 13 including the sensing float 13a is lowered by gravity, the rotary valve 32 of the adjustment valve 17 is moved in the β direction as shown in FIG. As a result, the flow path 44a causes the flow path 44a to immediately enter the above-described throttle state, and the state is fully opened (a throttle standby state W). In the planting posture A of the working machine 9 shown in FIG. As shown in (2), the main path 31 and the output path 34 are connected so as to be in the maximum throttle state (full throttle state S) in which the main path 31 and the output path 34 are completely closed.

When the operating lever 22 is switched to the position "b" from the state in which the working machine 9 is raised by the above-described structure, the working machine 9 is lowered as described above. However, as shown in FIG. The front end portion of the sensing float 13 (sensing float 13a) comes into contact with the field scene, and then the sensing rod 27 moves in the β direction by swinging the sensing float 13a in the a direction. This allows the control valve 17 to
9A, the rotary valve 32 rotates in the β direction via the adjusting arm 46 from the throttle standby state W shown in FIG. 9A, as shown in FIG. As shown in FIG. 10 (c), when the working machine 9 is in the planting posture A, the entire throttle state S {FIG. 9 (b)} is reached, and the drainage of oil from the hydraulic cylinder 18 is controlled only through the bypass 37. It is sent to the valve 16 side.

That is, after the float 13 starts to touch the field, the drainage oil (pressure oil) from the hydraulic cylinder 18 is discharged to the input path 33 through the main path 31 and the output path 34 which are fully opened by the flow path 44a. ) Is gradually throttled by the rotation of the rotary valve 34, the amount of oil drained per unit time is reduced, the contraction operation of the hydraulic cylinder 18, that is, the lowering speed of the working machine 9 is gradually reduced, and the working machine 9 The float 13 hits the surface of the field and the ground contact surface 15 of the float 13 stably completes the contact without the mud, etc., and is in the planting posture A, and the control valve 16 is in the underlap state.

On the other hand, in the planting posture A of the work machine 9 (including the planting work state), the work machine 9 is inclined such that the front end side of the sensing float 13a swings in the direction a as shown in FIG. In this case, the sensing rod 27 moves in the β direction, and the sensing arm 24 rotates in the β direction. The rotation of the sensing arm 24 pulls the rod 26 in the β direction, and the switching arm 23a rotates in the β direction. Therefore, the operation shaft 16a is rotated from Y1 to Y2 in FIG. 3, the control valve 16 is switched to send the hydraulic oil to the hydraulic cylinder 18, the hydraulic cylinder 18 is extended, and the work machine 9 is raised.

At this time, the regulating valve 17
Connecting rod 4 connected to rod 26 with movement in the direction
7 moves in the β direction, and the rotary valve 32 (valve 44)
1 (a) {from the full aperture state S shown in FIG. 9 (b)}
In the direction shown in FIG.
4b, the main path 31 and the output path 34 are opened in accordance with the rising amount of the sensing float 13a, and the pressure path from the control valve 16 is opened by a predetermined amount, the main path 31 and the output path 34, and the check path through the check valve. The work implement 9 is sent to the hydraulic cylinder 18 through the bypass passage 36 and the bypass passage 37, and rises at the same speed as the conventional one.

Thereafter, as the work machine 9 rises and the work machine 9 changes to a state substantially parallel to the field as shown in FIG. 6, the front end side of the sensing float 13a swings in the direction b. As the work machine 9 rises, the sensing rod 27 moves in the α direction and the sensing arm 24 rotates in the α direction, whereby the rod 26 is pulled in the α direction and the switching arm 23a rotates in the α direction, When the work machine 9 is substantially parallel to the field, the operation shaft 16a returns to the range of Y1 in FIG. 3, the control valve 16 is in the underlap state, the posture of the work machine 9 is maintained, and the planting depth is maintained. . At this time, the connecting rod 47 is pulled in the α direction with the movement of the rod 26 in the α direction, and as shown in FIG.
2 rotates in the α direction, and when the work machine 9 becomes substantially parallel to the field, the state returns to the full throttle state S shown in FIG.

When the work machine 9 is tilted such that the front end of the sensing float 13a swings in the direction b, the sensing rod 27 moves in the direction α and the sensing arm 24 rotates in the direction α. , The rod 26 is pulled in the α direction, the switching arm 23a rotates in the α direction, and the operation shaft 16a is
The control valve 16 is turned from 1 to Y3, the control valve 16 is switched to the compression operation side of the hydraulic cylinder 18 where the hydraulic oil in the hydraulic cylinder 18 can be discharged, and the work implement 9 descends.

At this time, as the rod 26 moves in the α direction, the connecting rod 47 connected to the rod 26 moves in the α direction, and the adjustment valve 16 is shown in FIG. 12 (a) {FIG. 9 (b)}. When the rotary valve 32 rotates in the α direction from the full throttle state S, the flow path 44a moves from the output path 34 to the main path 31 according to the rotation angle of the rotary valve 32 as shown in FIG. Since the throttle of the oil drained from the hydraulic cylinder 18 is opened, the working machine 9 starts descending at a speed corresponding to the opening of the throttle.

As the work machine 9 changes to a state substantially parallel to the field as shown in FIG. 6 when the work machine 9 descends, the front end side of the sensing float 13a swings in the direction a. With the lowering of the work machine 9, the sensing rod 27 moves in the β direction and the sensing arm 24 rotates in the β direction, whereby the rod 26 is pulled in the β direction and the switching arm 23a
Rotates in the β direction, and when the work machine 9 is substantially parallel to the field, the operation shaft 16a returns to the range of Y1 in FIG. 4, the control valve 16 is switched to the underlap state, and the posture of the work machine 9 is maintained. Sauce, planting depth is maintained.

At this time, the connecting rod 27 is pulled in the β direction with the movement of the rod 26 in the β direction.
As shown in FIG.
As described above, the lowering speed of the working machine 9 gradually decreases as described above, and when the float 13 touches the ground without any inconvenience such as hitting the field surface, the working machine 9 becomes substantially parallel to the field. The control valve 17 is shown in FIG. 12 (d) {FIG. 9 (b)}.
The operation returns to the full aperture state S as shown in FIG. In other words, the adjustment valve 17 provided separately from the control valve 16 allows
As described above, the raising of the working machine 9 at the time of the automatic raising and lowering control of the working machine 9 is controlled by the control valve 16 as in the related art, regardless of the throttle operation by the adjusting valve 17 as described above. 17 controls the speed adjustment.

The lowering speed of the working machine 9 is determined by the rotation angle of the rotary valve 32, that is, the sensing float 13a as described above.
For example, when the cultivated soil on the field scene suddenly becomes shallow, the attitude of the sensing float 13a greatly changes in the direction b, and the work machine 9 descends at a relatively high speed. To start the work machine 9
Does not deteriorate the field following ability.

As described above, when the working machine 9 is lowered from the raised position according to the present invention, the float 13
After a part of the (sensing float 13a) is grounded, the working machine 9
Of the float 13 is prevented from hitting the ground surface 15 of the float 13 against the cultivated soil surface of the field.
Pitching and mud pushing can be eliminated.

At this time, the control valve 16 is configured to operate in conjunction with the sensing link mechanism 28 for the control valve 16 to automatically control the lifting and lowering of the work machine 9 via the connecting rod 47. The change in the attitude of the work machine 9 (the swing of the sensing float 13 a) in which the control float 16 operates is more accurately transmitted to the control valve 17, and the work machine 9 after the sensing float 13 a is grounded by the control valve 17 with the operation of the control valve 16. The operation of lowering the descending speed is more accurately performed.

The control valve 17 is provided with a rotary valve 32a.
The above-described throttle operation is performed by the rotation of the hydraulic cylinder 18.
Since this is a rotary valve for adjusting the lowering speed of the (working machine 9), the adjusting valve 17 can be easily linked to the sensing link mechanism 28 by the connecting rod 47, and the adjusting valve 17 operates the sensing link mechanism 28. The aperture operation can be performed more accurately and smoothly.

Since the control valve 17 is mounted separately from the control valve 16, the control valve 17 and the connecting rod 47 are not provided.
The descending speed adjusting device constituted by the above can be assembled, and the descending speed adjusting device (adjusting valve 17) can be easily added to a conventional riding rice transplanter or the like.

When the work machine 9 is lowered by the automatic control of raising and lowering the work machine 9, the lowering speed is adjusted according to the amount of change in the attitude of the sensing float 13a (work machine 9). Open main path 31 and output path 3
4 and the check passage 36, the hydraulic oil
The working machine 9 rises at the same speed as that of the prior art. In addition, when the working machine 9 is manually lifted by the operation lever 22, the above-described structure does not allow the adjusting valve 17 to perform the above-described adjusting operation. Since it is the same as the conventional one,
The followability of the working machine 9 to the field is improved without lowering the sensitivity of the automatic lifting and lowering control, and the working efficiency is not greatly reduced as compared with the related art.

When the control valve 16 is in the underlap state of the control valve 16, the throttle valve is in the maximum throttle state. Since the hydraulic cylinder 18 is expanded and contracted from the squeezed state, a sudden change in pressure oil does not occur in the hydraulic circuit for lifting and lowering the working machine 9, and so-called jumping (vibration) of the working machine 9 is prevented. .

On the other hand, generally, in a relatively hard field, the work machine 9 performs planting and running with the front end of the float 13 (the sensing float 13a) slightly inclined upward (in the direction of), and the adjustment valve 17 is operated as shown in FIG. As shown in (a), the main path 31 and the output path 34 are not completely closed, and the flow path 4
4b, it is opened by a predetermined amount. That is, at the start of the automatic lifting / lowering control of the work implement 9, the adjustment valve 17 is in a state having an error corresponding to the opening from the maximum throttle state.

When the work machine 9 is tilted so that the front end side of the sensing float 13a swings in the direction b from this state, first, when the swing amount of the sensing float 13a is relatively small, as shown in FIG. As shown, the main path 31 and the output path 34 are opened by a predetermined amount by the flow path 44b,
As described above, the lowering speed does not gradually decrease as described above (because the main path 31 and the output path 34 are not fully opened, the lowering speed is lower than the conventional one by the throttle amount). At this time, since the swing amount of the sensing float 13a is relatively small, the descending amount of the work machine 9 is relatively small, and the work machine 9 descends at a slower speed than the descending speed of the conventional work machine which does not perform the throttling operation. Such problems do not generally occur.

Second, when the swing amount of the sensing float 13a is relatively large, the main path 31 and the output path 34 are opened by a predetermined amount by the flow path 44a as shown in FIG. Then, the working machine 9 descends while gradually decreasing the descending speed, and the same effect as above can be obtained. The swing of the sensing float 13a causes the adjustment valve 17 to rotate.
However, there is a case where the main path 31 and the output path 34 are in the maximum throttle state in which the main path 31 and the output path 34 are completely closed. The lowering speed of the work implement 9 is the lowest speed (the work implement 9 when the control valve 17 is in the maximum throttle state).
Lowering speed). As described above, even when the field is relatively hard and the swing amount of the float 13 (the sensing float 13a) is relatively small, the work machine 9 has relatively high followability to the field and the workability is not spoiled. .

When the connecting rod 47 is connected to the other connecting part 46c of the adjusting arm 46 instead of the connecting part 46b, as shown in FIGS. 14 and 15, the connecting part of the connecting rod 47 and the adjusting arm 46 is connected. 46c is located above the valve mounting portion 46a, and the adjusting arm 46 rotates in the β direction via the connecting rod 47 as the rod 26 moves in the α direction, and the rod 26 moves in the β direction. With connecting rod 4
7, the adjusting arm 46 is rotated in the α direction.

The rotary valve 32 of the adjusting valve 16 is mounted on the rotary valve 32 of the adjusting valve 16 by the mounting structure of the connecting rod 47 so that the working machine 9 is lifted from the state where the front end of the float 13 (the sensing float 13a) is lowered by gravity. As shown in FIG. 9D, the flow path 44a communicates with the output path 34 so that the output path 34 and the main path 31 are always fully opened during the rotation in the range where the plant is lowered to the planting posture A. I do. In other words, Z shown in FIGS. 14 and 15 is a range in which the throttle of the adjustment valve 17 is fully opened, and the rotation of the adjustment arm 46 from the rising state of the work implement 9 to the planting posture A is within a range of Z1 included in the Z. Become.

As a result, as shown in FIG. 14, when the operating lever 22 is switched to the position b from the state in which the working machine 9 is raised and the working machine 9 is lowered, the front end of the sensing float 13a comes into contact with the field scene. Even if the sensing rod 27 moves in the β direction and the rotary valve 32 rotates in the α direction, since the rotation of the adjustment arm 46 is within the range of Z1, the adjustment valve 17 , The work implement 9 descends at the same speed as in the prior art to take the planting posture A, and the control valve 16 enters the underlap state.

In the planting posture A of the working machine 9 shown in FIG. 15, the working machine 9 is tilted so that the front end side of the sensing float 13a swings in the direction a, and the sensing rod 27 moves in the β direction to move the sensing float 13a. Even if the work machine 9 rises as shown in
The adjustment arm 46 is swung in the α direction, but the control valve 16
Is sent to the hydraulic cylinder 18 through the check path 36 of the control valve 17, and the working machine 9 rises at the same speed as the conventional one. Thereafter, as the work implement 9 moves upward, the sensing rod 27 moves in the α direction, and as described above, when the posture of the work implement 9 is maintained, the rotary valve 32 rotates in the β direction, and the adjustment valve 17 turns the output path. 34 and the main path 31 are fully opened, and the throttle operation by the rotary valve 32 is not performed.

In the planting posture A of the working machine 9, the working machine 9 is inclined so that the front end side of the sensing float 13a swings in the direction b, and the sensing rod 27 moves in the α direction to move the working machine 9 as described above. 9 descends, the adjusting arm 46 swings in the β direction. In this case, the adjusting valve 17 is connected to the output path 3.
4 and the main path 31 are kept open, and the throttle operation by the rotary valve 32 is not performed. Therefore, the working machine 9 starts to descend at the same speed as the conventional one, and the sensing rod 27 while the working machine 9 is descending.
When the adjusting arm 46 swings in the α-direction due to the movement in the β-direction, the adjusting valve 17 keeps the state in which the above-described throttling operation is not performed. Without this, it descends at the same speed as the conventional one, and becomes the planting posture A.

That is, the control valve 17 is connected to the flow passage 4 of the valve 44.
By adjusting the positional relationship between 4a and the output path 34 by the mounting position of the connecting rod 47 and the adjusting arm 46, there is a non-operating range in which the throttle operation is not performed. By changing the connecting point between the adjusting arm 46 and the connecting rod 47 as described above,
The hydraulic circuit 20 for lifting and lowering the work machine 9 is connected to the control valve 1
7 can be switched to use. Note that the positional relationship between the flow passage 44b and the output passage 34 may be adjusted by the attachment method of the connecting rod 47 and the adjustment arm 46, or the like, and may be switched to use the non-operating range of the adjustment valve 17.

At this time, the mounting structure of the connecting rod 47 and the connecting portion 46b can be the same as the mounting structure of the connecting rod 47 and the connecting portion 46c. Can be changed from the connecting portion 46b to the connecting portion 46c without changing the structure of the end portion of the connecting rod 47 from the connecting portion 46b to the connecting portion 46c. Become. Thus, use or non-use of the descending speed adjusting device (adjusting valve 17) can be easily selected, and the descending speed of the hydraulic circuit 20, that is, the working machine 9, can be easily made to correspond to the field state.

[0050]

According to the structure of the present invention configured as described above, only when the control valve is in the neutral position, the control valve is in the maximum throttle state, and the control valve raises or lowers the work machine. In this case, the control valve is sequentially opened from the maximum throttle state. Therefore, there is an advantage that unnecessary delay caused by the control valve being in the maximum throttle state does not occur in the lifting / lowering control of the work implement performed by the control valve.

[Brief description of the drawings]

FIG. 1 is a left side view of a riding rice transplanter.

FIG. 2 is a hydraulic circuit for lifting and lowering a work machine.

FIG. 3 is a front view showing the operation of the control valve.

FIG. 4 is a plan view of a lever guide.

FIG. 5 is a right side view of a lifting link portion at the start of sensing float grounding.

FIG. 6 is a right side view of the lifting link portion when the sensing float is in the planting posture.

7A is a front sectional view, a partial left side view, and a partial bottom view of the control valve, and FIG. 7B is a front sectional view of the control valve.

FIG. 8 is a partial plan view of a hydraulic link portion.

FIGS. 9A and 9B are cross-sectional views of the control valve showing a state of the valve.

FIGS. 10 (a), (b), and (c) are main part partial sectional views showing the operation of a control valve accompanying the operation of the working machine when the working machine is grounded.

FIGS. 11 (a), (b), (c) and (d) are partial cross-sectional side views of a main part showing the operation of an adjustment valve accompanying the swinging operation of the work implement.

FIGS. 12 (a), (b), (c) and (d) are partial cross-sectional side views of a main part showing an operation of an adjustment valve accompanying a swinging operation of a working machine.

FIGS. 13 (a), (b) and (c) are main part partial sectional views showing the operation of a control valve accompanying the operation of a work machine in a relatively hard field.

FIG. 14 is a right side view of an elevating link portion at the start of sensing float grounding with the control valve switched to a non-operating state.

FIG. 15 is a right side view of an elevating link portion in a planting posture of a sensing float in which a control valve is switched to a non-operating state.

[Explanation of symbols]

 6 traveling body 8 lifting link (link mechanism) 9 work implement 13 float 16 control valve 17 adjusting valve 18 hydraulic cylinder 44a flow path 44b flow path

Claims (2)

[Claims] 1. An implanting work machine (9) provided with a vertically oscillating float (13) below it is connected to a traveling machine body (6) so as to be able to move up and down via a link mechanism (8). A hydraulic cylinder (18) that drives the working machine (9) up and down is interposed between the mechanism (8) and the traveling machine body (6), and controls the hydraulic cylinder (18) to raise and lower the working machine (9). A control valve (16) for controlling the float (1) is provided in a hydraulic circuit between the control valve (16) and the hydraulic cylinder (18).
An adjustment valve (17) for reducing the lowering speed of the work machine (9) at the time of grounding in 3) is provided, and the adjustment valve (17)
The control valve (16), which holds the transplanting height of the working machine (9) by grounding the float (13), has a mechanism for maximizing the squeezing state at the time of the neutral posture. A lowering speed adjusting mechanism for the transplanter, wherein the control valve (16) is switched from the neutral position to the upward or downward direction of the work machine (9) to sequentially shift from the maximum throttle state to the open state. 2. The control valve (17) has a control valve (1).
The two flow paths (4) of which one of them is selectively opened by the operation in the upward or downward direction from the maximum throttle state of (7).
4. A lowering speed adjusting mechanism for an implanting machine according to claim 1, wherein said lowering speed adjusting mechanism comprises 4a) and (44b).