JP3297203B2 - Work machine lifting control device for agricultural tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work implement elevation control device for an agricultural tractor which automatically sets the height of a work implement connected to the rear of the machine body so as to be able to move up and down, and automatically controls the height.

[0002]

2. Description of the Related Art Conventionally, a work machine is mounted on a rear part of a machine body so as to be able to move up and down, and the work machine is moved up and down by a hydraulic device. There is already known a work implement lifting / lowering control device in a farm tractor which is controlled via a link mechanism by a detection result of a vessel and a feedback mechanism.

[0003]

The above-mentioned known work tractor lifting / lowering control device for an agricultural tractor includes a link mechanism, a link base for operating a control valve, and one end linked to a lifting / lowering control lever (plowing depth control lever). A lifting / lowering control (PAC) link having one end linked to the work implement height detector, and one end linked to the position control lever and the other end being a hydraulic switch.
The position control lever is composed of a position link that is linked to a feedback mechanism that feeds back the operation of the cylinder, and a fulcrum pin that rotatably connects the middle part of those links. Since it was set to the lowest position, there is a recess in the field , for example, with the ground work depth set to the shallowest.
When carry signal from the detector is eliminated by working machine positive
The lowest position set with the control lever
In some cases, it may fall to the lower limit.
To the next when the carry signal from the detector is inputted, the working machine rises rapidly from significantly lowered posture to the set height by the elevation control lever, such control operation is repeated so-called hunting phenomenon Occurred.

[0004]

According to the present invention, a work machine is mounted on an airframe so as to be lifted and lowered by a hydraulic device, and a lift control valve of the hydraulic device is provided with a position control lever and a lift control valve.
Manual operation means consisting of a working depth control lever , a work implement height detector attached to the work implement, and operation of the hydraulic cylinder
In the agricultural tractor in which a feedback mechanism for feedback is linked with a feedback mechanism via a link mechanism to control the lifting and lowering of the work implement, the link mechanism is provided at one end with a plowing depth control lever.
The other end is linked to the work equipment height detector, and one end is connected to the position control lever.
There and position link which is linked to the feedback mechanism, constituted by linking a link base connected to the elevation control valve at fulcrum pin, also abuts Positional the position linked to said elevator control link
Attach a restricting device to limit the lowering operation of the ink
The control lever to the lowest position
Automatic control of work equipment height with control lever set to the shallowest
The lifting signal from the work implement height detector
When the cylinder is lowered, the restrictor is
Set the lowering position of the work implement via the
The above problem was solved by preventing the working machine from remarkably descending .

[0005]

When the position control lever, which is a manual operating means, is operated, the position link is rotated, whereby the link base and the control valve are operated, so that the working machine is raised and lowered, and the position control lever is set to the lowest position. Elevation control lever as manual operation means
When the (tilling depth control lever) is set to a desired position, during operation, the elevation control link rotates and activates the elevation control valve according to the detection result of the detector. It is controlled to the set position. Then, in a state of setting shallow ground work depth, when Nari carry signal from the detector Do <br/> rather lowered operation of the hydraulic cylinders is performed, restricting mechanism attached to the elevating control link position Link to
Contact with the work machine via this position link.
Since the movement is blocked at the set position, the work implement does not descend significantly, and therefore no hunting phenomenon occurs.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the agricultural tractor shown in the drawings. A hydraulic housing 1 of a hydraulic device is mounted on a transmission case A at the rear of the machine body. , A rotary tilling device is connected so as to be able to ascend and descend by a top link and left and right lower links, and lift arms 3, 3 mounted on both sides of a lift shaft 2 supported on a rear portion of the hydraulic housing 1 are connected via lift rods. To the middle of the lower link,
A distal end of the power arm 5 having a base portion spline-fitted to an intermediate portion of the lift shaft 2 is connected to a piston 7 of a hydraulic cylinder 6 via a piston rod 8.

A lift control valve 10 interposed in an oil passage leading to the hydraulic cylinder 6 is mounted at the center of the lower surface of the hydraulic housing 1, and a link base 11 is connected to a spool 10a projecting rearward from the lift control valve 10. The link base 11 is provided with a return spring 12 having a rear portion locked by a plate-shaped holder 14. On the right side of the hydraulic housing 1, a position control lever 15 and a cultivation depth control lever 16 are supported by support shafts 15a, 16a. And friction plates 18, 18 are interposed between the bosses of the levers 15, 16 and the valve bracket 17, and the disc springs 19, 1 are provided on the outside.
The levers 15 and 16 are braked and held at a desired set position by superimposing the bolts 9 and tightening them with bolts. On the lower surface of the valve bracket 17, a horizontal control electromagnetic valve 17a (the control cylinder is one side) is provided. And a valve block 17b attached thereto, and the valve block 17b is bored in the hydraulic housing 1 by a strong return pipe 17c that extends laterally and is bent downward. Since it is connected to the oil port communicating with the lift control valve 10, it can be held firmly.

A lower portion of a sensor lever 21 is mounted on the outer side of a support shaft 20 penetrating the left side of the hydraulic housing 1 and a sensor arm 24 is mounted on an inner end thereof. A plate 22 pivotally supports an upper part of a bending link 23 which is opened downward, and a lower end of a front side thereof and a pin 21 a on an upper part of the sensor lever 21 are connected to a rod 25.
The lower end of the rear portion of the refraction link 23 is
Since it is connected via wires to the tillage depth detection arm, which is a working machine height detector attached to the rear cover of the tillage device, the ground height of the tillage device fluctuates (the tillage depth fluctuates) and the rear cover rotates. When it moves, it is moved to the sensor lever 2
Transmit to 1.

Further, on the rear part of the link base 11,
An intermediate portion of the elevation control link 27 is disposed on the lower surface, and an intermediate portion of the position link 28 is disposed on the lower surface.
The right side of the lifting control link 27 is shorter than a predetermined length, and a plate is welded to the upper surface of the end to extend the predetermined length to form an upward step 27a. The left side of the lower part 28a is made shorter than a predetermined length, and a plate having a large thickness is welded to the lower surface of the end to extend it to a predetermined length.
An arm 31 fixed to the inner end of the support shaft 15a of the position control lever 15 is linked via a link 32 to an upper part of a position arm 33 whose middle part is loosely fitted to the support shaft 16a. The lower portion of 33 is in contact with the rear surface of the position link 28.

A control arm 36 fixed to the inner end of the support shaft 16a of the cultivation depth control lever 16 is suspended below the upward step 27a, and a horizontal pin 34 is fixed to a lower portion thereof. Abuts on a vertical receiving pin 35 fixed to the rear surface of the upward step 27a. The sensor arm 24, which is fixed to the inner end of the support shaft 20 of the sensor lever 21 and is hung down, The horizontal pin 38 fixed to the lower end of the vertical step portion 28a abuts on a vertical receiving pin 39 fixed to the left rear surface of the elevation control link 27.

A halfway bent portion of the feedback link 40 is fitted to the support shaft 20, and a hanging portion at the front of the feedback link 40 is formed by the downward step portion 28a.
The rear end of the power arm 5 is linked to the lower end of a link 41 connected to the rear end of the boss of the power arm 5 so that the rear end of the power arm 5 is operated. When rotated, the feedback link 40 is linked to the lower link 28 of the position link 28.
a is moved back and forth.

A pin-shaped restricting member 44 is fixed to the rear of the lifting control link 27 from the fulcrum pin 30 on the side of the manual operation means directly or via a plate 44a. Since the lifting control link 27 is set at a predetermined angle by the plowing depth control lever 16 because the link 28 is opposed to the rear surface of the link 28, the position link 28 moves forward and backward from the restricting tool 44, that is, forward and backward on the raising side. Although movement is allowed, movement backward from the restricting tool 44 is prevented.

In the drawing, 42 is a lubrication pipe for a piston rod, 43 is a lever panel, 45 is a hydraulic hose, 46 is a bracket of a flow dividing valve 47 for distributing pressurized oil to a lift arm actuating and horizontal control solenoid valve, 48 Is a descending speed adjusting device, 49 is a lift arm angle sensor for detecting the operating angle of the lift arm, and an intermediate part of the arm plate 48b is attached to the outer end of the adjusting shaft 48a of the descending speed adjusting device 48, and The brake is applied to the arm plate 48b by interposing a disc spring or the like and tightening, and a flow control lever 48d is connected to a front portion of the arm plate 48b via a connecting member 48c.
The arm plate 48b serves as a balancer so as not to tilt forward due to the weight of the flow control lever 48d, so that the posture of the flow control lever 48d can be held by a small friction. When the flow control lever 48d is pulled fully backward, the arm plate 48
b The rear part contacts the hydraulic housing 1 as a stopper,
When tilted forward, the seat portion of the adjustment shaft 48a comes into contact with the tapered surface of the oil passage and stops.

In the above-mentioned agricultural tractor, when the position control lever 15 is rotated back and forth, the arm 31 of the support shaft 15a which rotates integrally therewith rotates the position arm 33 back and forth through the link 32, and thereby the position Since the right side of the link 28 is moved back and forth, the spool 10a of the elevation control valve 10 connected thereto via the link base 11 is moved back and forth, and the piston 7 and the piston rod 8 are moved back and forth, so that the power arm 5, Since the lift shaft 2 and the lift arm 3 rotate, the tillage device moves up and down. At the same time, the power arm 5
The link 41 of the feedback mechanism causes the feedback link 40 to rotate back and forth with the rotation of, and the lower end of the front portion moves the lower step 28a of the position link 28 back and forth, so that the spool 10a moves back and forth to neutral. Return to position.

When the tilling operation is performed, the position control lever 15 is set to the lowest position, and the cultivation depth control lever 16 is set to an appropriate cultivation depth. At that time, on the other hand, the right side of the position arm 33 is rotated backward to the maximum, the control arm 36 is retracted to the set position, and the sensor arm 24 is at an angle corresponding to the detection value of the tillage depth detector. During the tillage operation, when the tillage depth is shallow, the sensor arm 24 pivots rearward by the detector down signal, so that the elevation control link 27 retreats around the right side whose position is regulated, and the link moves backward. When the base 11 retreats, the tillage device descends to a predetermined plowing depth, and when the detector emits a raising signal, the sensor arm 24 pivots forward, and the left side of the lifting control link 27 is pushed forward. Since the link base 11 moves forward against the return spring 12, the tillage device rises to the set tillage depth. Also, to rotate the aircraft, position control lever 1
5 is set to the raised position, the position arm 33 rotates forward and pushes the right side of the position link 28 forward, whereby the link base 11 is also pushed out. When 15 is set to the lowest position, the tillage device descends.

At the time of the lifting and lowering operation and the lifting and lowering control of the work machine, the cultivation depth control lever 16 side (right side) of the lifting and lowering control link 27 is configured as the upward step 27a. It can be lowered close to the upper surface, so that the control arm 36 can be formed long and its working stroke can be sufficiently ensured. The opposite side (left side) of the position link 28 from the position control lever 15 is a downward step portion 28a.
Therefore, even if the support shaft 20 serving as the upper fulcrum of the sensor lever 21 is set at a low position, its working length can be sufficiently secured, and the downward step portion 2 can be secured.
Since the vertical width of 8a is widened, even if the lower end of the feedback link 40 moves up and down with the forward and backward rotation of the feedback link 40 which must be formed long, it can be reliably received.

An example of the arrangement of various operating means will be described with reference to FIGS.
3 is provided, and the cultivation depth control lever 16 is provided on the outside of the rear portion.
A position control lever 15 that is frequently used inside and forward of the position control lever 15 and the cultivation depth control lever 16
The O shift lever 52 is connected to each of the levers 15, 16, 5
2 are arranged in a staggered manner, near the front of the guide groove of the position control lever 15, and at the front end of the guide groove of the cultivation depth control lever 16 and the rear end of the guide groove of the PTO speed change lever 52. A horizontal control switch 53 for intermittent horizontal control and a manual horizontal dial 54 are provided between the position control lever 1 and the position control lever 1.
In operating the fifth embodiment, the elbow could be prevented from interfering with the support frame 55. In addition, each lever 15, 16, 5
2. The states of the horizontal control switch 53, the manual horizontal dial 54, and the like can be checked at the same time, and erroneous operations such as forgetting to shift and forgetting to switch on can be prevented. Reference numeral 56 denotes a grip that the driver grips when getting on and off the vehicle.

[0018]

According to the present invention, as described above,
Abut the position link 28 on the
Attach a restricting tool 44 for restricting the lowering operation of the
Set the position control lever 15 to the lowest position
The working machine height with the working depth control lever 16 set to the shallowest.
During automatic control, no lifting signal from work implement height detector
When the lowering operation of the hydraulic cylinder 6 is performed,
The brace 44 is located below the work implement via the position link 28.
Set the lowering position, which prevents the implement from lowering significantly
During the automatic control of the height of the work equipment,
Position link by the restrictor 44 attached to the lock 27
28 is restricted and set by the restrictor 44.
Hydraulic cylinder 6 further below the set position control position
It does not rotate to the side, and it is a simple means,
It is possible to prevent the work machine from remarkably descending and to surely prevent the work machine from causing a hunting phenomenon.

[Brief description of the drawings]

FIG. 1 is a side view of an elevation control device for an agricultural tractor.

FIG. 2 is a bottom view in which a part of the above is cut away.

FIG. 3 is a longitudinal sectional view of the same.

FIG. 4 is a side view of an operation link mechanism and a feedback mechanism.

FIG. 5 is a plan view of the elevation control device.

FIG. 6 is a side view of a transmission mechanism of the work implement-to-ground height detector.

FIG. 7 is a side sectional view of the control device.

FIG. 8 is a perspective view of a main part of the control device.

FIG. 9 is a perspective view of an operation unit.

FIG. 10 is a transverse sectional view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic housing 10 Elevation control valve 11 Link base 15 Position control lever 16 Tillage depth control lever 27 Elevation control link 28 Position link 44 Regulator

────────────────────────────────────────────────── ─── Continued on the front page Examiner Yasushi Miyazaki (56) References JP-A-1-148108 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A01B 63/10 A01B 63 / 114

Claims (1)

(57) [Claims] 1. The working machine is lifted and lowered on the machine body by a hydraulic device
So that the hydraulic device lift control valve(Ten)ToPo
Position control lever (15) and tillage control lever (1
6) consists ofManual operation means and attached to the work machineWorking machine height
SaA detector,Feedback of hydraulic cylinder (6) operation
DoA feedback mechanism and a link mechanism(27), (28), (1
1)Working machine linked withLifting controlAgriculture
Tractor, wherein the link mechanism(27), (28), (11)
And one endThe other end of the working depth control lever (16) is
To the dispatcherLinked lifting control link(27)When,One end is positive
Feedback to the control lever (15)
Linked to the mechanismPosition link(28)And the lifting system
Your valve(Ten)Link base linked to(11)And the fulcrum
N(30)By linking withAlso,The lifting system
Your link (27)ToPosition link(28)In contact withPosition
Link (28)Regulator to limit lowering operation(44)Mounting
Ke, Lower the position control lever (15)
With the tillage control lever (16) set to the shallowest
During the automatic control of the height of the work equipment, raise the height from the work equipment height detector.
No signal, hydraulic cylinder (6) lowered
At this time, the restricting tool (44) is moved via the position link (28).
To set the lowering position of the implement,
Prevent descentAgricultural tractors characterized by the following:
Work equipment elevating control device.