JPH06253608A - Lift control mechanism for working device - Google Patents

Abstract

PURPOSE:To provide a lift control mechanism designed to automatically control the lowering speed of a working device to a desired speed taking advantage of a traction load detecting means to be used in working traveling. CONSTITUTION:A working device 5 is connected, via a three-point link mechanism, to a running machine body so as to be vertically movable on driving by a single-acting hydraulic cylinder 6, and a control unit to control a hydraulic control mechanism on a hydraulic cylinder 6 and a sensor 12 to detect the traction load of the working device 5 on the left and right lower links 3, 3 in the three-point link mechanism 4 are equipped. In this lift control mechanism for working device, the control unit is designed to be switchable between the control mode to make automatic control of the hydraulic control mechanism so that the results from the sensor 12 come to a set value and the manual lift mode by operational implements. And, the hydraulic control mechanism can be controlled so as to automatically change the flow of oil discharged from the hydraulic cylinder 6 during lowering actuation of the working device 5 based on the results from the sensor 12 when the device 5 is in such a stationary state as to be floating above the ground.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control for connecting a working device to a traveling machine body through a three-point link mechanism so as to be driven up and down by a single-acting hydraulic cylinder, and switching control of a hydraulic control mechanism for the hydraulic cylinder. Means and a towing load detecting means for detecting the towing load of the working device applied to the left and right lower links in the three-point link mechanism, and the control means has the detection result of the towing load detecting means to be a set value. As described above, the present invention relates to a lifting control mechanism for a working device which is configured to be switchable between an automatic control mode for controlling the hydraulic control mechanism and a manual lifting mode by an operating tool.

[0002]

2. Description of the Related Art In the lifting control mechanism of the above working device,
Conventionally, as disclosed in, for example, Japanese Utility Model Laid-Open No. 4-82402, a variable throttle valve whose throttle amount is adjustable by a manual rotation operation is provided in a supply / discharge oil passage for the hydraulic cylinder. .

[0003]

The above-mentioned structure is, for example,
When the work equipment is replaced with a different type, such as when the plow equipment is replaced with a rotary tiller, the weight of the work equipment is different. Since the flow rate of the discharged oil at the time of changing changes the descending speed of the working device, in such a case, the descending speed can be set to a desired speed by adjusting the variable throttle valve. However, in the case of the above-mentioned conventional structure, there is a drawback that the adjustment work becomes troublesome because it is configured by a screw feed rotation operation type in order to accurately adjust the valve opening degree of the variable throttle valve,
Moreover, since the actual descending speed of the working device with respect to the adjustment amount can be confirmed only by elevating and lowering the working device, it is necessary to repeat the adjusting work a plurality of times until the desired speed can be set. Yes, there was room for improvement. The present invention effectively utilizes the load detection means provided in this type of work machine in order to detect the towing work load,
The purpose is to solve the above problems.

[0004]

A characteristic configuration of the present invention is that the detection value of the towing load detection means when the working device is in a stopped state in which the working device is levitated above the ground in the lifting control mechanism of the working device described at the beginning. On the basis of the above, there is provided a flow rate control means for controlling the hydraulic control mechanism so as to automatically change the flow rate of the oil discharged from the hydraulic cylinder when the working device is lowered.

[0005]

When the work device is grounded while being towed, the detected value of the towing load detection means for detecting the towing load from the displacement of the lower link which causes the towing load of the working device and the displacement of the bending amount is the set value. When the working device is automatically moved up and down so as not to exceed the limit, and when the working device is largely lifted at the time of turning such as a ridge, the manual operation mode is used. Then, the detection value of the towing load detection means when the work device is set to the state of levitating above ground in the manual operation mode is the detection value in the state where the entire weight of the work device is applied to the lower link. By automatically controlling the oil discharge flow rate from the hydraulic cylinder when the working device is descending according to the detected value, the descending speed is maintained at the desired state regardless of what working device is installed. Can be made.

[0006]

Therefore, even when the working device is replaced with a different one by effectively utilizing the detection information of the load detecting means conventionally provided for detecting the towing load during work traveling, The descending and falling speed of the working device can be always automatically adjusted to a desired speed in the lowering operation that is performed by draining oil from the single-acting hydraulic cylinder by the weight of the working device without requiring complicated operations such as screw rotation adjustment. It has become possible to improve work efficiency.

[0007]

Embodiments will be described below with reference to the drawings. Figure 4
Shows the rear part of the agricultural tractor. This agricultural tractor has a three-point link mechanism 4 including a top link 2 and a pair of left and right lower links 3 and 3 at a rear portion of a riding type traveling body 1.
A plow 5 [an example of a working device] is freely movable via a hydraulic cylinder 6, and a left and right lift arm 7 that swings up and down around a horizontal axis by a hydraulic cylinder 6 and each lower link 3 are interlockingly connected via a lift rod 8. Then, the plow 5 can be driven and moved up and down by the hydraulic cylinder 6. During plowing work, the ground level of the plow 5 is automatically lifted and lowered so that the pulling load of the plow 5 is maintained at a set value, and is also manually lifted to greatly raise the ground to the ground when the ridge turns and to descend to the ground again. It is configured to be able to. More specifically, as shown in FIG. 1, the hydraulic control valve 9 for the hydraulic cylinder 6 is composed of an electromagnetic proportional flow control valve capable of changing and controlling the valve opening, that is, the hydraulic flow rate in accordance with the supply current. This electromagnetic proportional flow rate control valve 9, which is an example of a control mechanism, is electrically controlled by a control device 10 [an example of control means] equipped with a microcomputer. Then, near the airframe side fulcrums of the left and right lower links 3, 3 in the three-point link mechanism 4, a traction load sensor 12 (a traction load detection means) for detecting a load on the fulcrum pin 11 due to a towing operation based on distortion of the fulcrum pin 11 or the like. ], And a potentiometer-type lift arm angle sensor 13 for detecting the relative angle of the lift arm 7 to the machine body is provided, and the machine body control section is provided with a potentiometer-type load setter 14 and a potentiometer-type machine, respectively, which are manually adjustable. The position setting device 15 (an example of an operating tool) is provided. Then, the control device 10 controls the traction load sensor 12
The automatic control mode in which the electromagnetic proportional flow rate control valve 9 is automatically controlled so that the detected value of No. 1 matches the set value of the load set value 14, the detected value of the lift arm angle sensor 13 and the set value of the position setter 15 match. As described above, the electromagnetic proportional flow control valve 9 is configured to be freely switchable to a manual operation mode, and the manual operation mode can be set prior to the automatic lifting control mode.

Then, based on the detection value of the load detection sensor 12 when the plow 5 is in a stopped state of floating above ground,
The control device 10 is provided with a flow control means A for controlling the electromagnetic proportional flow control valve 9 so as to automatically change the flow rate of the oil discharged from the hydraulic cylinder 6 when the plow 5 is lowered, in the form of a control program. The control device 10 executes control as follows. As shown in FIG. 2, if the adjusting operation switch 16 is turned on after the plow 5 is raised to the ground floating position by manual operation [steps 1 and 2], the set value by the potentiometer-type descending speed adjuster 17 is set. Based on this, the proportional constant k is set [step 3]. And
The detection value of the load detection sensor 12 at this time is read, and the target flow rate at the time of descending operation is obtained from the detection value W and the proportional constant k by map data [steps 4 and 5],
Further, the duty ratio of the pulse drive current to the electromagnetic proportional flow rate control valve 9 is calculated from this target flow rate and stored (steps 6 and 7). The proportional constant k can be changed by the descending speed setting device 17 to change and adjust the descending target speed.

Next, the lifting operation of the plow 5 will be described. As shown in FIG. 3, when the set value by the position setting device 15 is a low level for plowing work, the automatic lifting control mode is set, and the tow load detected by the load detection sensor 12 becomes the set value by the load setting device 14. The electromagnetic proportional flow rate control valve 9 is automatically controlled so as to achieve the above [steps 1 and 2]. And
If the value set by the position setter 15 is at the floating level above the ground, the position control mode is set manually (step 3). In this position control,
While sequentially reading the outputs a and b of the position setter 15 and the lift arm angle sensor 13, the position setter 1
If the set value a by 5 is larger than the detected value b by the lift arm angle sensor 13, the plow 5 is moved upward, and the set value a by the position setter 15 substantially matches the detected value b by the lift arm angle sensor 13. If so, the neutral state is maintained [steps 4 to 8]. If the set value a set by the position setter 15 is smaller than the detected value b set by the lift arm angle sensor, the pulse current according to the lowering duty ratio calculated and stored in the adjustment control mode is applied to the electromagnetic proportional flow control valve 9. And the plow 5 can be lowered at a predetermined target speed [step 9].

It should be noted that reference numerals are added to the claims to facilitate the comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a control block diagram.

[Fig. 2] Adjustment control flowchart

[Fig. 3] Lifting control flowchart

FIG. 4 is a side view of the rear part of the agricultural tractor.

[Explanation of symbols]

 3, 3 Lower link 4 3 point link mechanism 5 Working device 6 Hydraulic cylinder 9 Hydraulic control mechanism 10 Control means 12 Traction load detection means 15 Operation tool

Claims (1)

[Claims] 1. A hydraulic control for the hydraulic cylinder (6), wherein a working device (5) is connected to a traveling machine body by a single-acting hydraulic cylinder (6) so as to be driven up and down by a three-point link mechanism (4). A control means (10) for controlling the mechanism (9),
The control means (10) is provided with a towing load detecting means (12) for detecting a towing load of the working device (5) applied to the left and right lower links (3) and (3) of the three-point link mechanism (4). ) Is an automatic control mode for controlling the hydraulic control mechanism (9) so that the detection result of the traction load detection means (12) reaches a set value, and an operating tool (15).
A lifting control mechanism for a working device configured to be switchable to a manual lifting mode by the working device (5).
The work device (5) based on the detection value of the towing load detection means (12) when the vehicle is floating above ground
Hydraulic control mechanism (9) for automatically changing the flow rate of oil discharged from the hydraulic cylinder (6) during the lowering operation of
An elevating control mechanism for a working device, which comprises a flow rate control means (A) for controlling