JP3772539B2 - Work equipment lifting control device for work vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention reduces the impact on a lifting link device or work implement caused by rattling of the lifting link device or the like when transporting the work implement on a work vehicle that connects the work implement so as to be able to be lifted and lowered via the lifting link device. The present invention relates to a working machine lifting control device.
[0002]
[Prior art]
Agricultural work vehicles such as tractors connect work machines via lifting link devices such as parallel link mechanisms and three-point link mechanisms, and operate the lifting link devices with actuators such as hydraulic cylinders to raise and lower the work machines. It has become. When transporting work implements with this type of work vehicle, the operation of the lift link device is stopped and the work implement is held at a certain height from the ground, but the lift link device itself is caused by road surface unevenness, transmission, brakes, etc. As a result, rattling occurs in the connecting portion between the lift link device and the work implement, and the work implement swings up and down or back and forth. The swing of the work implement is transmitted to the work vehicle via the lifting link device, and not only the stability of traveling is impaired, but also the lifting link device may be damaged if the swinging shock is large. Conventionally, however, no special measures have been taken for this.
[0003]
[Problems to be solved by the invention]
It is an object of the present invention to suppress stable shaking of a working machine caused by rattling of the lifting link device or the like so that stable traveling can be performed.
[0004]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is configured as follows. That is, the work implement lifting control apparatus for a work vehicle according to the present invention is a work machine lift control apparatus for a work vehicle that connects the work machine (25) so as to be lifted and lowered via a lift link device (20). Elevating means (26 ) for raising and lowering (25) , detecting means (31) for detecting that the work vehicle is in a high-speed traveling state, and rattling of the elevating link device (20) or work implement (25). Sensing means (32) for moving up and down, a lifting switch (11) for raising and lowering the working machine (25) to a working position and a non-working position, a position lever (15) for raising and lowering the working machine to an arbitrary height, and the lifting means A control means (13) for controlling the operation of (26) and a mode changeover switch (16) for changing the elevation control mode by the control means (13), the mode changeover switch (16 Is set to a lift control mode that alleviates rattling of the work implement, and the sensing means (32) senses rattling while the detection means (31) detects a high-speed traveling state of the vehicle. When the position lever (15) or the lift switch (11) is operated, the lift control is canceled when the working machine is controlled to move up and down in a direction to reduce the rattling. It is said.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a state in which a work machine is transported by a tractor which is an agricultural work vehicle. This tractor 1 is provided with an engine 2 at the front part of the fuselage, a clutch case 3 at the rear side, and a transmission case 4 at the rear side. Front wheels 5 and 5 are supported under the engine 2 so as to be steerable. The rear wheels 6 and 6 are pivotally supported on the left and right sides of the rear part of the transmission case 4.
[0006]
Fenders 8 and 8 are attached from the front to the top of the left and right rear wheels 6 and 6, and a seat 9 is installed between the left and right fenders. A steering handle 10 for steering the front wheels 2 and 2 is provided in front of the seat 9. On the lower side of the steering handle 10, a lift switch 11 is provided for moving the working machine up and down between a working position and a non-working position. Further, on the side of the seat 9, there is a control box 14 that houses a controller 13 to be described later, a position lever 15 that raises and lowers the work implement to an arbitrary height, and a mode change switch 16 that switches the raising / lowering control mode. Etc. are provided.
[0007]
A lifting link device 20 of a three-point link mechanism is provided at the rear of the machine body. The lift link device 20 includes a pair of left and right lower links 21 and 21 and a top link 21 at the center of the left and right. The lift arms 23 and 23 and the intermediate portions of the lower links 21 and 21 are connected by lift rods 24 and 24. is doing. One lift rod 24L (left side in the illustrated example) is a rolling cylinder. The work machine 25 is supported at three points at the rear ends of the lower links 21 and 21 and the top link 22. The figure shows the state which connected the rotary tiller as a working machine. When the lift cylinders 23, 23 are turned up and down by extending and lowering the lift cylinder 26, which is a lift means, the work machine 25 moves up and down. Further, when the rolling cylinder 24L is expanded and contracted, the right / left inclination of the work machine 25 is adjusted.
[0008]
FIG. 2 is a block diagram of the tractor work implement lifting / lowering control apparatus A. On the input side of the controller 13 which is a control means, the lift switch 11, a position lever sensor 30 for detecting the operation position of the position lever, and the angle of the lift arm. The lift arm angle sensor 31 for detecting the load, the draft sensor 32 for detecting the load applied to the lower link, the tilling depth sensor 33 for detecting the tilling depth of the rotary tiller as a work machine, and the mode change switch 16 are connected to the output side. Further, a raising solenoid 34 and a lowering solenoid 35 of a proportional solenoid valve for controlling the raising / lowering cylinder 26 are connected.
[0009]
When the position control mode is selected with the mode changeover switch 16, when the position lever 15 is operated, the raising solenoid 34 or the lowering solenoid 35 is set so that the detected value of the lift arm angle sensor 31 matches the angle indicated by the position lever sensor 30. The work machine 25 is raised and lowered to a height corresponding to the operation position of the position lever 15. Further, when the lift switch 11 is operated to the work machine raised position, the work machine is raised to a predetermined non-work position, and when the lift switch 11 is operated to the work machine lowered position, the work machine is lowered to the predetermined work position.
[0010]
When the draft control mode is selected with the mode change switch 16, if the detected value of the draft sensor 32 exceeds a certain value during work, the work machine 25 is raised by outputting it to the raising solenoid 34, and the engine load becomes too large. Control to not.
[0011]
When the mix control mode is selected by the mode changeover switch 16, the tilling depth control for raising and lowering the work machine 25 with respect to the tractor 1 so as to maintain the tilling depth constant based on the detection value of the tilling depth sensor 33 and the draft control are performed. Perform together.
[0012]
When the transport control mode is selected with the mode changeover switch 16, when the detection value of the lift arm angle sensor 31 exceeds a certain value, that is, when the detection value of the draft sensor 32 temporarily increases when the tractor is in a non-working state, After output to the lowering solenoid 35 and lowering the work machine 25 slightly (lifting the lift arms 23, 23), it is output to the raising solenoid 34 and controlled to return the work machine 25 to its original height. In such a case, for example, when the work machine 25 is held at a certain height, the work machine 25 is moved to the work vehicle by the amount of rattling of the lifting / lowering link device 20 due to speed changes such as road surface unevenness and sudden braking. In contrast , the work machine 25 is expected to rise due to the reaction. Therefore, by lowering the work implement 25 in advance with respect to the work vehicle by the height difference corresponding to the lowering (lifting the lift arms 23, 23), the impact on the lifting link device 20 is reduced. In this work implement lifting control device, the lift arm angle sensor 31 detects a high-speed traveling state of the work vehicle, that is, a non-working state, and the draft sensor 32 senses a lifting link device or a work implement rattling. It has become. Note that the high-speed traveling state of the work vehicle may be detected from the shift position.
[0013]
Since transport control ( control to alleviate rattling of work equipment during high-speed traveling) is limited to control when the tractor is in a high-speed traveling state, forgetting to return the mode switch 16 to a mode other than the transport control mode. If the position lever 15 or the lift switch 11 is operated during the transport control mode, the transport control mode is automatically canceled.
[0014]
FIG. 3 is a block diagram of a different work implement lifting control apparatus B, and FIG. 4 is a hydraulic circuit diagram of a work implement lifting hydraulic apparatus for a tractor equipped with the work lift control apparatus. When the hydraulic device sucks and pressurizes the hydraulic pressure from the tank T by the pump P to the lift cylinder 26 via the lift switch valve 40, the work machine is lifted, and the hydraulic oil in the lift cylinder 26 is moved to the lift switch valve 40. The work implement is lowered when it is returned to the tank T. In addition to the hydraulic fluid return circuit that passes through the up / down switching valve 40, a hydraulic fluid return circuit for shock absorption is routed, and an open / close valve 41 having a throttle is provided in the return circuit. The pressure at the pump port of the elevation switching valve 40 is detected by a pressure sensor 42.
[0015]
In this work implement lifting control device B, the pressure sensor 42 is used as a sensing means for sensing the backlash of the lift link device or work implement. When the transport switch 43 is turned ON, the transport control mode is set, and the control shown in the flowchart of FIG. 5 is performed. That is, in the transport control mode, when the detected value of the pressure sensor 42 becomes abnormally high, the on-off valve 41 is opened, the hydraulic oil in the elevating cylinder 26 is returned to the tank T through the throttle, and the work implement is lowered. . As a result, the impact caused by rattling of the lifting link device or work implement is reduced. When the hydraulic oil in the lift cylinder 26 is returned to the tank T, the on-off valve 41 is closed and the lift switching valve 40 is driven to the work machine lifting side to feed the hydraulic oil into the lift cylinder 26 and the work machine is Return to the original height. The value of the pressure sensor 41 that opens the on-off valve 41 and the value of the pressure sensor 41 that closes the on-off valve 41 can be adjusted by the shock absorption setting dial 44 according to the weight of the work implement. Note that the above control is performed only when the lift switch 11 is at the work machine ascending position, and the lift link device is lifted and lowered during the operation to damage the lift link device and the hydraulic equipment. Is preventing.
[0016]
Further, as in the work implement lifting control device C shown in FIG. 6, an engine speed sensor 50 or a vehicle speed sensor 51 is provided, and when an impact due to rattling of the lift link device or work implement is detected, the engine is shifted down. May be configured to output to the shift solenoid 52 or the fuel injection pump 53 so that the engine speed decreases.
[0017]
【The invention's effect】
As is clear from the above description, the work equipment lifting device in the work vehicle according to the present invention is subject to shock caused by rattling of the lift link device or work equipment during non-working with high speed traveling such as when the work equipment is transported. Even if it occurs, this can be suppressed, so that stable running can be maintained and breakage of the lifting link device and the like can be prevented.
[Brief description of the drawings]
FIG. 1 is a side view showing a state in which a work machine is transported by a tractor.
FIG. 2 is a block diagram of a work implement lifting control device.
FIG. 3 is a block diagram of a different work implement lifting control device.
FIG. 4 is a hydraulic circuit diagram.
FIG. 5 is a flowchart of transport control.
FIG. 6 is a block diagram of a further different work implement lifting control device.
[Explanation of symbols]
A, B, C Work implement lifting control device 1 Tractor (work vehicle)
13 Controller (control means)
16 Mode change switch 20 Elevating link device 25 Working machine 26 Elevating cylinder (elevating means)
31 Lift arm angle sensor (detection means)
32 Draft sensor (sensing means)
42 Pressure sensor (sensing means)

Claims (1)

A work implement lift control device for a work vehicle that connects the work implement (25) so as to be capable of being lifted and lowered via a lift link device (20) , the lift means (26) for raising and lowering the work implement (25) ; A detection means (31) for detecting that the vehicle is traveling at high speed, a sensing means (32) for detecting rattling of the lift link device (20) or the work machine (25) , and the work machine (25) at the work position. A raising / lowering switch (11) for raising and lowering to a non-working position, a position lever (15) for raising and lowering the working machine to an arbitrary height, a control means (13) for controlling the operation of the raising and lowering means (26), A mode switching switch (16) for switching the lifting control mode by the control means (13), wherein the mode switching switch (16) is set to a lifting control mode for alleviating rattling of the work implement, and When the detection means (32) detects rattling while the detection means (31) detects the high-speed running state of the vehicle, the work implement is controlled to move up and down in a direction that reduces the rattling. A work implement lifting control device characterized in that when the position lever (15) or the lifting switch (11) is operated, the lifting control is canceled .

Images