JPH0553442B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to an automatic tillage depth control device for automatically keeping the rotary tillage depth constant in a tractor.
More specifically, the present invention relates to an automatic plowing depth control device that detects plowing depth using a rotary rear cover or the like, and controls a valve based on the detected value to raise and lower a lift arm so that the plowing depth is constant.

(b) Conventional technology Conventionally, automatic tillage depth control devices can be roughly divided into mechanical types and electric types. The mechanical type transmits the vertical movement of the rotary rear cover to a cable via a link, which then rotates the link on the tractor body side to operate the control valve, and the movement is transmitted purely mechanically. It is something to do.
On the other hand, with the electric type, the rotation of the rotary rear cover is transmitted to a plowing depth sensor consisting of a potentiometer, and the sensor converts the rear cover position, that is, the plowing depth, into a voltage change and transmits it to the controller, which then sends it to the set value. The electromagnetic switching valve is operated based on the comparison and judgment.

(d) Problems to be solved by the invention By the way, in the mechanical type, the amount of rotation of the rotary rear cover is transmitted to the control valve via a cable and a link, so the transmission is caused by the connection play and deflection of the link that inevitably occurs. Performance deteriorates and is further exacerbated by poorly adjusted cables that are too tight or too loose. In addition, once the links are connected, the amount of movement of the rear cover determines the amount of operation of the control valve due to the fixed transmission ratio of the link mechanism, so depending on the work conditions, the frequency of switching the control valve may be increased or decreased. cannot perform any operations.

On the other hand, in the case of an electric type, the rotary can be connected to the controller of the tractor body using an electric wire, no adjustment of the transmission cable is required, and there is extremely little mechanical transmission loss. Further, in the controller, it is also possible to adjust the switching frequency of the valve by adjusting the dead band width in which no output is output within a certain range of the signal from the plowing depth sensor relative to the set value. However, since the electric type uses an electromagnetic switching valve, the movement of the manual lift lever must be converted into a voltage change using a potentiometer, and the manual operation part also needs to be modified. An even more important problem is that in the case of a mechanical type, a slit is provided in the spool of the control valve, which can be tightened when switching from neutral to upward, thereby easily eliminating the shock when the rotary rises, but in the case of an electric type, Ordinary electromagnetic switching valves cannot control the flow rate, and the rotary is raised rapidly, resulting in uneven surfaces on the surface of the finished soil after tilling. For this reason, it is necessary to use an electromagnetic switching valve for pulse width modulation (PWM) control, and in the case of a slight increase, it is necessary to repeatedly cycle between neutral and raising, but as the size of this high-performance electromagnetic switching valve increases, It is expensive, creates problems in installation space, and causes a significant increase in cost.

(d) Means for Solving the Problems The present invention aims to solve the above-mentioned problems by using a mechanical control valve for lift arm elevation control, and by using a mechanical control valve for automatic control of plowing depth. The signal from the rotary rear cover that constitutes the detection member is converted into a voltage change by a plowing depth sensor, and the controller compares it with a set voltage to operate an actuator, and the actuator operates a mechanical control valve. It is something to do. That is, as shown in FIG. 1, a manual lift lever 1 is connected to a link mechanism 2 for position control and automatic tillage depth control,
The mechanical control valve 3 is operated by the lift arm 5, and the movement from the lift arm 5 is fed back to the mechanism 2. Further, the vertical movement of the lift arm 5 based on the valve 3 is transmitted to the rotary 6, and furthermore, the tilling depth is detected by the rear cover (tilting depth detection member) 7 of the rotary 6, and the voltage is changed by the tilling depth sensor 9 consisting of a potentiometer. The signal from the sensor 9 is then input to the controller 10. The controller 10 also has a comparison/judgment circuit A, a plowing depth setter B that can be set arbitrarily by the operator, a dead band width setter C, and an output circuit D. The output circuit D sends a predetermined signal to the actuator 11. and send the actuator 11
is connected to a mechanical control valve 3 via a linkage 2.

(E) Effect Based on the above-described configuration, the control valve 3 is operated via the link mechanism 2 based on the operation of the manual lift lever 1, and the lift arm 5 is rotated by the hydraulic cylinder to move the rotary 6 up and down. Then,
The amount of rotation of the lift arm 5 is fed back to the link mechanism 2, and the control valve is returned to the neutral position at the rotation position of the lift arm 5 corresponding to the operating position of the manual lever 1, so-called position control. Furthermore, when the rear cover 7 comes into contact with the ground as the rotary 6 descends and the plowing depth of the rotary 6 is detected, the plowing depth amount by the rear cover 7 is converted into an electric signal by the plowing depth sensor 9, and the signal from the sensor 9 is The controller 10 compares and determines the plowing depth set value from the plowing depth setter B and the dead zone value from the dead zone width setter, and outputs the signal to the actuator 11. As a result, actuator 1
1 operates the control valve 3 so that the detected value from the plowing depth sensor 9 and the set value from the plowing depth setter B match.

(f) Examples Examples of the present invention will be described below with reference to the drawings.

The tractor 15, as shown in FIG.
A driver's seat 19 consisting of a seat 17 and the like is disposed in the fuselage 16, and a hydraulic system 20 is disposed below the driver's seat 19. The hydraulic system 20 includes a tank 21, a hydraulic pump 22, a mechanical control valve 3, and a hydraulic cylinder 23, and the hydraulic cylinder 23 is connected to the lift arm 5 via a power arm 25. Further, a lower link 26 and a top link 27 are connected to the rear of the fuselage 16, and a lift arm 5 is connected to each of the lower links 26 via a lift rod 29. Furthermore, these lower links 26 and top links 27 has rotary 6
are connected, so the tractor 15 is equipped with the rotary 6 by means of a special three-point linkage device, and
Power is transmitted through the joint 28. Also,
The rotary 6 has a main body 30, a tilling claw 31, a main cover 32, etc., and the main cover 32
A rear cover 7 is rotatably supported by a pivot pin 33 behind the rear cover 7 . The rear cover 7 presses down the soil tilled by the tilling claws 31 from above to level it, and can also detect the tilling depth H based on the rotational position of the rear cover 7. Further, a plowing depth sensor 9 consisting of a potentiometer installed on the rotary body 30 is connected to the rear cover 7 via a link 34, and the sensor 9 measures the plowing depth based on the rotational position of the rear cover 7. Convert H into voltage change. Further, a controller 10 is disposed in the tractor driver's seat 19, and a signal from the plowing depth sensor 9 is connected to the controller 10 by an electric wire. Furthermore, an actuator 11 consisting of an electric cylinder, a hydraulic cylinder, etc. is installed adjacent to the tractor hydraulic system 20.
is provided, the actuator 11 is controlled by a signal from the controller 10, and
It is connected to a control valve 3 via a link mechanism 2 which will be described later.

As shown in FIG. 3, the link mechanism 2 is connected to the manual lift lever 1, and the link mechanism 2 is
The arm 36 is connected to one end of a position control link 37 by a connecting pin 37a. Furthermore,
The other end of the control link 37 is connected to a feedback link 38 by a connecting pin 37b, and the link 38 is connected to an arm 40 rotatably supported around a pivot shaft 39 by a pin 40a. are doing. Further, the other end of the arm 40 is connected to an arm 41 via a pin 40b, and the arm 41
The other end is connected to the power arm 25, which rotates together with the lift arm 5, by a pin 41a.
On the other hand, an arm 42 rotatably supported by the pivot shaft 35 has one end connected to it by a pin 43a, and an automatic plowing depth control link 43 is disposed adjacent to and overlapping the position control link 37.
The other end of the control link 43 is connected to a link 45 via a pin 43b. The arm 42 is held at a predetermined position by an automatic plowing depth control operating lever (not shown) or the like so that one end pin 43a of the automatic plowing depth control link 43 is at a predetermined position. Furthermore, the other end of the link 45 is connected by a pin 45a to an arm 46 that is rotatably supported around the pivot shaft 39.
It is connected to the actuator 11 via a link 47 that integrally rotates around the center. The actuator 11 has three positions in which it can move in the M direction and in the anti-M direction with respect to the neutral position. Further, the control valve 3 has a spool 3a biased downward by a spring 49, and a valve link 5 at the tip of the spool 3a.
0 is concatenated. Furthermore, the valve link 50
A continuous traction pin 50a is connected to the tip of the position control link 37 and the automatic tillage depth control link 43, and the pin 50a is connected to the pivot shaft 35.
The arm 51 is connected to and supported by an arm 51 rotatably supported by the arm 51.

The mechanical control valve 3 also has a slit 5 in a portion of the spool 3a communicating from the pump port P to the cylinder port S, as shown in FIG.
2 is formed, and a restriction acts at the beginning of communication with the cylinder port S of the spool 3a, so that oil is gradually sent from the pump port P to the cylinder port S.

Since this embodiment has the above configuration,
When the manual lift lever 1 is rotated in the upward direction as shown by the arrow X, the arm 36 rotates together and the position control link 37 is rotated counterclockwise about its lower end pin 37b. As a result, the control link 37 comes into contact with the connecting pin 50a, moves the spool 3a against the spring 49, and operates the control valve 3 in the upward direction. Then, at the start of operation, the oil in the hydraulic pump 22 is first squeezed from the pump port P through the slit 52 and is gradually sent to the cylinder port S. Therefore, the hydraulic cylinder 23 lifts the lift arm 5 without applying a shock. The structure and rise, and further link devices 26, 2
The rotary 6 is raised via 7. Also, as the lift arm 5 rises, the arrow Y of the power arm 25
The rotation in this direction causes the position control link 37 to rotate counterclockwise via the arms 41, 40 and the feedback link 38, this time around the pin 37a at the upper end. As a result, the continuous traction pin 50
a is gradually returned in the direction of arrow Z, but when the lift arm 5 is rotated to a position corresponding to the operating position of the manual lift lever 1, the control valve 3 is returned to the neutral position.

In addition, when the manual lift lever 1 is fully lowered as shown in FIG.
detects the plowing depth H, and the rotational position of the rear cover 7 is further converted into a voltage change by the plowing depth sensor 9.
Then, the signal from the sensor 9 is transmitted to the controller 1.
Sent to 0. On the other hand, in the controller 10 of the driver's seat 19, the operator operates the setting dial in advance to set the plowing depth setter B to a predetermined voltage and the dead band width setter C to a predetermined sensitivity depending on the field. put. In this state, the signal from the plowing depth sensor 9 is compared with the set plowing depth value in the comparison/judgment circuit A, and if both values exceed the dead band width, an output signal is issued from the output circuit D to the actuator 11. The actuator 11 is driven in a predetermined direction. For example, when the actuator 11 is moved in the direction M in FIG. anti-arrow Z
move in the direction. As a result, the spool 3a is moved in the upward direction against the spring 49, the control valve 3 is operated to rotate the lift arm 5, and the plowing depth H by the rear cover 7 is set to the value set by the controller 10. Plowing depth is automatically controlled. Then, when the rotary 6 rises and the voltage from the plowing depth sensor 9 based on the rear cover 7 falls within a predetermined dead band width based on the plowing depth setting device B, the actuator 11 moves in the anti-M direction and returns to the neutral position. do. Further, when the signal from the tillage depth setter B is a downward command, the actuator 11 moves in the anti-M direction and operates the control valve 3 in the downward direction.
When the rotary 6 reaches the set position, the actuator 11 is moved in the M direction and returned to the neutral position.

Note that during the automatic plowing depth control, the manual lift lever 1 is fully rotated in the lowering direction as shown in FIG. 3, so the position control link 37 comes into contact with the continuous traction pin 50a. There is no interference from the manual operation system during automatic plowing depth control. On the other hand, when performing manual position control, an automatic tillage depth control activation lever (not shown) is used.
Either rotate the arm 42 counterclockwise from the position shown in FIG. 3 to retract the automatic plowing depth control link 43 so that it does not come into contact with the continuous traction pin 50a, or set the actuator 11 in a free state to prevent plowing during position control. Prevent deep automatic control from interfering.

Therefore, if automatic plowing depth control is not required, the actuator 11 and link 47 can be removed, and there is no need to change the manual operation system. If it is incorporated into the system, it is extremely easy to add an automatic tillage depth control device later.

Also, during automatic tillage depth control, based on the slit 52 of the control valve 3, oil is throttled and gradually sent to the hydraulic cylinder 23 at the start of raising, and the rotary 6 is controlled to ascend so that there is no shock. Of course.

(G) Effects of the Invention As explained above, according to the present invention, the amount of movement of the plowing depth detection member (rear cover) 7 is determined by the plowing depth sensor 9.
Since the system converts the signal into an electrical signal and sends the signal to the controller 10, it is possible to eliminate link connection play and bending, which are disadvantages of mechanical deep-plowing automatic devices, as well as performance and accuracy deterioration due to poor cable adjustment. However, since a mechanical control valve 3 is used, it is possible to operate without using a high-performance electromagnetic switching valve such as a PWM control electromagnetic switching valve.
By forming the slit 52 etc. in the spool 3a, it is possible to eliminate the shock when the lift arm 5 starts to rise, and while it has an extremely simple, inexpensive and compact configuration, it can achieve smooth and highly accurate plowing depth and finish after plowing. Soil surface can be obtained. Further, the manual lift lever 1 is connected to the control valve 3 via the link mechanism 2, and the actuator 1 is operated by the controller 10.
1 to the control valve 3 via the link mechanism 2.
Since it is connected to the electric plowing depth automatic control, the operating system using the manual lifting lever 1 is almost the same as the conventional one, and the hydraulic system 20 is connected to the hydraulic system 20, which eliminates the need for the plowing depth automatic control. It is possible to standardize the system, significantly reducing the manufacturing cost, and it is also possible to easily add an automatic tillage depth control device later. Also,
Since it has a dial-type plowing depth setting device B, the plowing depth can be set extremely accurately and easily while visually checking it, compared to a lever-type device. Furthermore, since the dead zone width setting device C is provided, the dead zone width can be arbitrarily set according to field conditions, etc., and stable automatic control of plowing depth can always be performed regardless of field conditions. And position control link 3
7 and the tillage depth automatic control link 43 are arranged adjacent to each other, and one mechanical control valve 3 can be directly controlled by these two links.
Since the position control link 37, the automatic tillage depth control link 43, and their interlocking links are all arranged to move within a vertical plane, for example, both control links are arranged on a horizontal plane and the other interlocking links are arranged on a vertical plane. If they are arranged on different planes, the structure becomes complicated because ball joints and axial contraction mechanisms are required for the interlocking parts between the different planes, but if they are all arranged on vertical planes, the interlocking is done by pivot pins. is sufficient, the structure is simple, and
It can be constructed compactly, and it is also easy to add the interlocking link 47 from the actuator 11 to the automatic tillage depth control link 43, making it possible to easily attach this type of automatic tillage depth control device.

[Brief explanation of the drawing]

Fig. 1 is a control block diagram of the present invention, Fig. 2 is a side view showing a tractor and rotary to which the present invention is applied, Fig. 3 is a side view showing its link mechanism, Fig. 4
The figure is a sectional view showing a mechanical control valve. 1...Position operation means (manual operation lever),
2...Link mechanism, 3...Mechanical control valve, 3a...Spool, 5...Lift arm,
6... Rotary, 7... Tilling depth detection member (rear cover), 9... Tilling depth sensor, 10... Controller,
11... Actuator, 15... Tractor, 20
...Hydraulic system, 37...Position control link,
43...Plowing depth automatic control link, 36, 38, 4
0, 41, 45, 46, 47... linked link, 5
2... Slit, B... Cultivation depth setting device, C... Dead band width setting device.

Claims (1)

[Scope of Claims] 1. A position operating means is interlocked with one end of the position control link via a connecting arm, and a lift arm is interlocked with the other end of the position control link via a feedback link, and the position control A position control device that controls a valve with a link to control the vertical position of the working machine according to the operating position of the position operating means, and a tilling depth detection member installed on the working machine to detect the plowing depth and detect the plowing depth. controlling the valve based on the detected value;
A tractor comprising: a tillage depth automatic device that controls the elevation of the working machine based on the tillage depth detection member, wherein the valve is a mechanical control valve, and the amount of movement of the tillage depth detection member is converted into an electric signal. A plowing depth sensor for conversion is provided, and a controller is provided that inputs the signal from the sensor, the signal from the dial-type plowing depth setting device, and the signal from the dead band width setting device and outputs it to the actuator. Then, the value from the tillage depth sensor is
When the dead zone set by the dead zone width setting device based on the value of the tilling depth setting device is exceeded, the actuator outputs an output, and is further interlocked with the actuator via an interlocking link and adjacent to the position control link. and a tilling depth automatic control link is provided, and the control valve is controlled via the tilling depth automatic control link based on the operation of the actuator, and the position control link and the tilling depth automatic control link, and the tilling depth automatic control link are arranged. A plowing depth control device for a tractor, wherein a connecting arm, a feedback link, and the interlocking link are all arranged on a vertical plane.