JPH084818Y2 - Dashing prevention control device for work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a dashing prevention control device for a work vehicle such as an agricultural tractor.

[Problems to be Solved by Prior Art and Invention] Generally, in this type of work vehicle, when the working unit set at the upper limit position is lowered to the working height,
For example, when the working part is a rotary cultivator, the plowing reaction force by the plowing blade acts and a forward force is exerted on the machine body, which causes the machine body to be strongly pushed forward in what is called a dashing action. Because it is dangerous to receive it,
Descenting is prevented by reducing the descending speed of the working unit to the dashing prevention speed before the working unit reaches the working height.

And there is a thing which does not use computer control but such mechanical control as such a dashing prevention.
It is necessary to adjust the dashing prevention control start position at the time of shipment from the factory or in the actual field work, when the working part is replaced or when the field conditions such as the working depth change. When the working part is lowered, the working part decelerates at the control start position, but since it continuously descends, accurate position confirmation cannot be performed, and as a result, accurate adjustment cannot be performed. I was told.

[Means for Solving the Problems] The present invention was conceived with the object of providing a dashing prevention control device for a work vehicle capable of eliminating these drawbacks in view of the above circumstances. To lower the work unit lowering speed by limiting the flow rate of the oil discharged from the working unit lifting hydraulic cylinder that swings the lift arm up and down when the working unit is lowered to the working height. In order to prevent dusting, the one end of the connecting rod whose length is adjustable in response to the swing of the lift arm is swingably supported on the machine side and a contact portion is formed. While being pivotally supported on the plate, it is moved to the oil discharge passage of the lift arm hydraulic cylinder to adjust the throttle amount by the lever for adjusting the throttle amount so as to decelerate the descending speed of the working part, and is adjusted. Aperture from aperture position A poppet configured to be movable on the releasing side is provided, and it interferes between the poppet and the abutting portion so as to position the poppet on the throttling releasing side until the middle of the descending stroke of the lift arm. In the descending stroke after the stage before reaching the working height, an operating pin for releasing the interference with the poppet and positioning the poppet in the throttle position is provided, and the position where the operating pin interferes with the poppet is the length of the connecting rod. It is performed by adjustment, and the maximum throttle state of the poppet is characterized by being set to the descending stop speed of the working machine.

According to the present invention, the dashing prevention control start position can be easily and accurately adjusted with mechanical control.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.
In the drawings, 1 is a traveling vehicle of an agricultural tractor,
A rotary tillage type working unit 2 is attached to a rear portion of the traveling machine body 1 via an elevating link mechanism 3. The working unit 2 is vertically moved up and down by a lift arm 5 that swings in conjunction with an expansion / contraction operation of a hydraulic cylinder 4 (single action type) described later. Further, 6 is a lifting operation lever for operating the hydraulic cylinder 4.

Reference numeral 7 denotes a hydraulic housing in which the hydraulic cylinder 4 and the like are integrally assembled. A support shaft 5a of the lift arm 5 is rotatably and horizontally passed through a rear end of the hydraulic housing 7. However, an operating arm 5b is fixedly provided at an intermediate portion of the support shaft 5a. The operating arm 5b contacts the cylinder rod 4a of the hydraulic cylinder 4 and is swung by the hydraulic operation. The lifting arm 5 swings up and down, and the working unit 2 moves up and down as described above.

On the other hand, reference numeral 8 denotes a control valve housed in the hydraulic housing 7. The control valve 8 supplies oil supplied from a hydraulic pump (not shown) to the hydraulic cylinder 4 in accordance with the operation of the elevating operation lever 6. The expansion and contraction of the hydraulic cylinder 4 is controlled by switching between a raised state in which the hydraulic cylinder 4 is fed, a lowered state in which oil in the hydraulic cylinder 4 is discharged to a hydraulic tank (not shown), and a neutral state. Also,
Reference numeral 9 is a flow control valve interposed between the hydraulic cylinder 4 and the control valve 8. The flow control valve 9 limits the discharge oil flow rate of the hydraulic cylinder 4 to reduce the descending speed of the working unit 2. In this case, the descending speed can be adjusted by changing the discharge oil flow rate by operating the adjusting portion 9a.

Reference numeral 10 denotes a dashing prevention device which is detachably attached to one side surface of the hydraulic housing 7. The dashing prevention device 10 is arranged so as to be interposed between the hydraulic cylinder 4 and the flow control valve 9 in the hydraulic mechanism. .
This is composed of a cylindrical case body 11 which is oriented in the vertical direction, a plug body 12 which closes the upper opening of the case body 11, and a speed adjusting lever 13 whose lower end penetrates the plug body 12 in a vertically threaded manner. A poppet 15 which is locked to the lower end of the speed adjusting lever 13 via a pin 14 so as to be movable in the vertical direction, and an operating pin 16 which is fitted in a lower opening of the case body 11 so as to be movable in the vertical direction However, in detail, the case body 11 is formed with a step portion 11a having different inner diameters at the top and bottom, and the step portion 1 is further formed.
A first oil port 11b and a second oil port 11c are formed in the upper and lower portions of 1a. Further, the poppet 15 is formed in a hollow shape, and the side surface thereof is formed with an engagement hole 15a in which the pin 14 is loosely fitted, and the bottom of the poppet 15 is further lowered by an inclined surface 15b. It is formed in a protruding mountain shape. The inclined surface 15b and the stepped portion 11a of the case body 11 have a slight gap A.
I have come to face each other.

On the other hand, 17 is a connecting rod, and the connecting rod 17 is
The rear end is eccentrically and pivotally attached to one end surface of the support shaft 5a,
Further, the front end of the plate 18 is pivotally attached to the hydraulic housing 7 so as to be swingably supported, so that the plate 18 is swung by being displaced in the front-back direction as the working unit 2 is moved up and down. Is a contact pin that contacts the lower end of the operating pin 16.
18a is provided.

Next, the operation of the anti-dusting device 10 shown in FIGS. 6A, B and C will be described. First, when the raising / lowering operating lever 6 is operated to the ascending side when the working unit 2 is at the lowering position, the oil sent through the control valve 8 flows into the anti-dusting device 10 from the second oil port 11c. But this oil is poppet
15 is pushed up to flow from the first oil port 11b to the hydraulic cylinder 4 to extend the hydraulic cylinder 4, whereby the working unit 2 is raised at a constant speed.

On the other hand, when the raising / lowering operation lever 6 is moved to the lower side while the working unit 2 is at the upper position, the control valve 8 is switched to discharge the oil in the hydraulic cylinder 4 and the first oil port 11
Oil flows into the anti-dashing device 10 from b. At this time, since the contact pin 18a of the plate 18 pushes up the actuating pin 16, the poppet 15 is also pushed up, and the gap A is widened, whereby the dashing prevention device 10 performs flow control. The valve 9 and above are allowed to discharge oil. In this state, the working unit 2 descends at a normal speed that is not decelerated. However, as the working unit 2 continues to descend, the operating pin 16 and the poppet 15 are displaced as the connecting rod 17 is gradually displaced forward.
Moves down. And when the poppet 15 reaches the lower limit position,
The upward movement of the poppet 15 is regulated by the pressure of the oil flowing into the hollow portion, and only the discharge of oil from the preset gap A is allowed (less than the allowable discharge amount of the flow control valve 9). Thus, the lowering speed of the hydraulic cylinder 4 becomes slower, and the lowering speed of the working unit 2 is reduced to the anti-dusting speed.

Further, in this device, the dashing prevention control start position and the dashing prevention speed are freely set and adjusted by adjusting the length adjusting turn bag 17a provided at the intermediate portion of the connecting rod 17 and the speed adjusting lever 13. Is ready to do. That is, Poppet 15
It is possible to set and adjust the dashing prevention control start position by adjusting the timing at which the lower limit position reaches the lower limit position by the turn bag 17a of the connecting rod 17, and the speed adjustment lever 13 can be rotated to adjust the speed. Move the lever 13 up and down with the guide of the plug 12 that is screwed,
Along with this, the poppet 15 moves up and down and the gap A changes, so that the discharge flow rate at the time of lowering operation of the working portion changes and the dashing prevention speed is adjusted. The lower limit position of the adjustment range is the inclined surface of the poppet 15.
15b is set at a position where it contacts the stepped portion 11a and closes the gap A.

In the embodiment of the present invention constructed as described above, in order to adjust the dashing prevention control start position, first the speed adjusting lever 13 adjusts the poppet 15 so as to close the gap A at the lower limit position, and then, By operating the lifting operation lever 6, the working unit 2 is lowered from the raised position. Then, the working unit 2 is stopped at the dashing prevention control start position where the deceleration is originally started, so that the currently set control start position can be accurately confirmed. And
By changing the rod length by the turn bag 17a of the connecting rod 17 based on this stop position, the dashing prevention control start position can be set and adjusted to an arbitrary position.

As described above, according to the embodiment of the present invention, when the working unit 2 descends, the descending speed is reduced to the dashing prevention speed at the stage before reaching the working height, and the dashing operation is performed. However, the speed adjustment range of the anti-dashing speed in the anti-dashing device 10 is set so that the lower limit of the adjustment range is set to the stop speed with the poppet 15 in the maximum throttle amount state. When confirming the control start position for adjusting the prevention control start position, the lowered working unit 2 can be stopped at the dashing prevention control start position. Therefore, the dashing prevention control start position can be confirmed, and the dashing prevention control start position can be set and adjusted to an arbitrary position based on this. As a result, it is possible to perform the factory adjustment and the readjustment in the field with high accuracy, and it is possible to always perform the optimum dashing prevention control.

[Advantages] In summary, since the present invention is configured as described above, it is possible to prevent dashing by lowering the descending speed to the dashing preventing speed at the stage before reaching the working height when the working unit descends. However, the adjustment of the dashing prevention position can be performed mechanically by adjusting the length of the connecting rod. When adjusting the position, if the poppet is set to the stopped state with the maximum squeezing amount, the descending working unit will stop at this adjusted position, and the start position of the dashing prevention will be accurate. You will be able to confirm. Therefore, even though the dashing prevention control is a mechanical one that does not rely on the computer control, the start position of the dashing prevention can be easily adjusted, and the factory adjustment and readjustment in the field can be performed accurately. As a result, the dashing prevention control corresponding to the working condition can be performed.

[Brief description of drawings]

FIG. 1 shows an embodiment of a dashing prevention control device for a work vehicle according to the present invention. FIG. 1 is an overall side view of an agricultural truck, FIG. 2 is a side view of a hydraulic housing, and FIG. FIG. 3 is a plan view of the same as above, FIG. 4 is a schematic explanatory view showing an essential part of the hydraulic mechanism, FIG. 5 is a vertical sectional view of a dashing prevention device, and FIGS. FIG. 7 is a longitudinal sectional view of an essential part of the dashing prevention device showing the adjustment range of the poppet when the descent operation is performed at the speed and when the descent operation is performed at the dashing prevention speed. In the figure, 1 is a traveling machine body, 2 is a working unit, 4 is a hydraulic cylinder,
5 is a lift arm, 10 is a dashing prevention device, 13 is a speed adjusting lever, 15 is a poppet, 17 is a connecting rod, and 17a is a turn bag.

Claims (1)

[Scope of utility model registration request] 1. A descending speed of a working unit by limiting a flow rate of oil discharged from a working unit lifting hydraulic cylinder for vertically swinging a lift arm when the working unit is lowered to a working height. When slowing down to prevent dusting,
One end of a connecting rod whose length is adjustable in response to the swing of the lift arm is swingably supported on the machine body side and is also supported on a plate having an abutment portion,
Move to the oil discharge passage of the lift arm hydraulic cylinder to adjust the throttle amount by the lever for adjusting the throttle amount to decelerate the descending speed of the working part, and move from the adjusted throttle position to the throttle release side. A poppet constructed so as to be movable is provided, and the poppet is interfered between the poppet and the abutment portion so as to position the poppet on the squeezing release side until the middle of the descending stroke of the lift arm. In the descending stroke after the stage before it becomes a sag, an operating pin for canceling the interference with the poppet and positioning the poppet at the throttle position is provided, and the position where the operating pin interferes with the poppet is adjusted by adjusting the length of the connecting rod. The maximum throttling state of the poppet is set to the descent stop speed of the work machine, and the dashing prevention control device for a work vehicle.