JPS5912407Y2 - Anti-dashing adjustment device on tractors - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a hydraulic actuation device for lifting and lowering a working machine that prevents douching in a tractor.

Conventionally, in tractors, especially small tractors,
Since the rotary work machine was descending at a substantially constant speed, the rotary blade touched the ground with considerable force, causing a so-called darting phenomenon in which the tractor was driven by the rotational force of the rotary blade.

Therefore, a douching prevention device has been proposed in which a pin is provided on the piston of the hydraulic actuator and the pin is fitted into the oil passage of the cylinder head to throttle the oil passage and reduce the descending speed of the rotary work machine. .

However, the degree of subsidence of the tractor differs depending on the hardness of the field, so even with this douching prevention device, since the machine body is subsidence in soft fields, There were cases where the rotary work machine touched the ground and was not able to sufficiently prevent dashing.

Therefore, the present invention has developed a tractor that eliminates the above-mentioned drawbacks by screwing a timing adjuster into the cylinder head so that it can be adjusted freely, and by providing an oil passage in the adjuster, it is possible to adjust the fitting timing between the oil passage and the pin. It is an object of the present invention to provide an anti-dutching adjustment device in the present invention.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

The tractor 1 has a body 5 supported by front wheels 2 and rear wheels 3, as shown in FIG. The driver's seat 7 is located in the vehicle.

Further, at the rear of the machine body 5, a rotary working machine 12 having a rotary blade 10 and a rear cover 11 serving as a plowing depth sensing sensor of an automatic plowing depth device is towed by a hitch 13 and can be raised and lowered by a lift arm 16 via a lift rod 15. The lift arm 16 is rotatably supported by a hydraulic case 18 disposed above the mission case 17 at the rear of the fuselage 5.

The hydraulic case 18 has a piston 20 as shown in FIG.
The piston 20 is connected to the lift arm 16 via a piston rod 23 and a lift fork 24.

One side of the cylinder 21 is closed by a cylinder head 25, and as shown in detail in FIG. It is set up.

Is there a timing adjuster in this round hole 26? 7 is screwed in, and one end of the adjuster 27 is connected to the cylinder head 25.
The knob 27a protrudes outward from the handle.

Also, the center of the adjuster 27 has a cylinder. An oil passage 28 having an opening 28 a to the tank 21 is provided,
The oil passage 28 communicates with a hydraulic control valve 30 via an oil passage 29 provided in the hydraulic case 18 .

The valve 30 is a work equipment lifting lever 3 provided in the driver's seat 7.
1. ) The spool 30a is operated by an automatic tilling depth device based on the sensing result of the burr cover 11.

Further, a throttle valve 32 is provided on the center line of the adjuster 27, and a threaded portion 33a of the twenty-one dollar 33 is screwed into the adjuster 27.

Further, one end of the twenty-one dollar 33 protrudes to the outside of the cylinder head 25, and an operation knob 34 is fixed thereto.

The tip of the twenty-one dollar 33 has an angle smaller than the opening angle of the valve seat 35, so the threaded portion 33 of the twenty-one dollar 33 has a smaller angle than the opening angle of the valve seat 35.
The degree of restriction of the oil passage 28 is adjusted by moving forward and backward by a.

In addition, a branch oil passage 36 is provided in the cylinder head 25 in parallel with the oil passage 28 provided on the center line, and the branch oil passage 361 allows oil from the cylinder 21 to flow in, but
A check valve 37 is provided to prevent discharge from the cylinder.

On the other hand, a pin 38 is installed in the center of the piston 20, and when the piston 20 approaches the cylinder head 25, the pin 38 is inserted into the opening 28a of the oil passage 28 by 1/100 (
They fit together with a gap on the order of mm).

Since the present invention has the above-mentioned structure, as shown in FIG. When the cylinder 30a is moved to the open position, the oil in the cylinder 21 is discharged through the oil passages 28 and 29 by the pressing force of the piston 20 based on the weight of the work implement 12, and the work implement 12 is lowered.

At this time, since there is a distance between the pin 38 and the opening 28a of the oil passage 28, the oil in the cylinder 21 flows through the throttle valve 32.
It decreases rapidly depending on the degree of aperture.

As shown in FIG. 3, when the rotary work machine 12 descends to a position slightly higher than the field, the tip of the pin 38 reaches the opening 28a of the oil passage 28;
Fit into H with a slight gap.

As a result, the opening 28a becomes greatly constricted, and the rotary work machine 12 slowly touches the ground and slowly descends to a predetermined plowing depth without causing a dabbing phenomenon.

Note that at this time, since the check valve 37 is closed, oil is not discharged through the branch oil passage 36.

In addition, in order to raise the rotary work machine 12, oil is sent to the oil passage 29 by operating the spool 30a of the control valve 30, and the oil is sent to the cylinder 21 via the check valve 37, and the pin 38 and the oil passage Even when the opening 28a of 28 is fitted, the rotary working machine 12 can be quickly raised.

If the tractor 1 is used in a soft field, the machine body 5 will sink and the rotary work machine 12 will touch the ground earlier, but the timing adjuster 2 is adjusted by the knob 27a.
7 to advance the adjuster 27 in the direction closer to the piston 20 due to the screw engagement with the female threaded portion 26a.

As a result, the timing at which the pin 38 fits into the opening 28a of the oil passage 28 is accelerated, and the descending speed can be adjusted to decrease just before the rotary work machine 12 touches the ground.

On the other hand, when the tractor 1 is used in a hard field, the timing adjuster 27 is adjusted to move away from the piston 20, and the timing at which the pin 38 fits into the opening 28a of the oil passage 28 is delayed. 12 can be prevented from decreasing the descending speed at an early stage.

Note that even with this adjustment, the throttle valve 32 is
Since it moves together with 7, the descending speed does not change.

As explained above, according to the present invention, by moving the timing adjuster 27 forward and backward, the rotary work machine 12
Adjusting the timing of the decrease in the descending speed of the adjuster 27 can be adjusted to the appropriate position according to the field conditions such as hardness, softness, etc., while not causing any problems to the tilling work such as limiting the plowing depth due to the formation of ice. &3 It can be set with a simple operation, and it is possible to prevent the occurrence of douching due to a delay in the lowering time in soft fields and the deterioration of work efficiency due to an early decrease in lowering speed in hard fields.

The viscosity of the oil varies depending on the season, and the lowering speed of the rotary working machine 12, especially the low lowering speed when the pin 38 fits into the oil passage opening 28a, changes, but the maximum speed is controlled by the throttle valve 32. Even if the lowering speed is adjusted by the adjuster 27, there is no change in the degree of restriction of the oil passage 28 by the throttle valve 32. There is no need to adjust the valve 32.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a tractor to which the present invention can be applied;
Fig. 2 is a sectional view showing the hydraulic actuating device according to the present invention;
The figure is an enlarged sectional view of the main part. 1...tractor, 20...piston, 21...
Cylinder, 22... Hydraulic actuation device, 25... Cylinder head, 26... Round hole, 26 a... Threaded part, 27... Timing adjuster, 28... Oil path,
28 a...opening, 32...throttle valve, 38...
pin.

Claims (1)

[Scope of utility model registration request] A circular hole having a female thread is provided on the center line of the inner diameter of the cylinder of a cylinder head of a hydraulic actuating device, a timing adjuster is screwed into the circular hole in a freely adjustable manner, and the timing adjuster has an opening in the center thereof. An oil passage is provided, and a throttle valve is provided to adjust the degree of restriction of the oil passage, and a pin is installed in the center of the piston of the hydraulic actuator, and the pin is inserted into the opening of the oil passage with a small gap. An anti-dutching adjustment device for a tractor, which is configured to be able to be engaged with the tractor.