JPH0123205Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is an invention that enables advanced position control of working equipment such as position control, depth control, and draft control in small agricultural tractors.

Traditionally, large agricultural tractors with over 50 horsepower have been equipped with hydraulic control devices that can perform position control, depth control, draft control, etc.
For small agricultural tractors with less than 20 horsepower, the hydraulic case etc. had to be made small, making it impossible to construct links to enable complex control.

The present invention enables complex control on small tractors by concentrating the structures of the links and levers of these control devices in a low position.

In conventional control devices,
- Position control setting lever, draft control setting lever (depth control setting lever) on one side of the hydraulic case, as in No. 30527.
Since a depth control feedback device and a position control feedback device were installed, one side was complicated in order to establish the mutual positional relationship of the links, and as a result, the hydraulic system became large. Separately, both setting levers and the valve control bar on which the feedback device operates are placed inside the transmission case on the bottom of the hydraulic case, and the hydraulic control valve is also suspended so that it is inside the transmission case. By arranging the hydraulic control device, the setting lever, feedback device, hydraulic control valve, valve control bar, etc. can be made as low as possible, and the entire hydraulic control device can be made small and low.

The purpose of the present invention is as described above, and the structure of the present invention will be explained based on the structure of the embodiment shown in the attached drawings.

Figure 1 is a right side view of the hydraulic control device of the present invention;
Figure 2 is a left side view, Figure 3 is a top view, Figure 4 is a bottom view, Figure 5 is A of Figure 3.
-A cross-sectional view as seen from the arrows, FIG. 6 is a BB--B cross-sectional view as seen in FIG. 5, FIG. 7 is a CC--C cross-sectional view as seen in FIG.
The figure is a sectional view taken along the line DD in FIG. 1, and FIG. 9 is a side view of the slide support of the valve control bar.

The hydraulic system has two large parts: hydraulic case 2,
It consists of a cylinder head 3 and lift arms 1L and 1R, and is placed on the rear axle housing or transmission case of an agricultural tractor and fixed with bolts.

As shown in FIG. 5, when pressure oil flows into the hydraulic cylinder 2a in the hydraulic case 2 from the oil passage of the cylinder head 3, the piston 7 is pushed rearward and the connecting rod 8 moves the piston 7 from side to side via the arm 9 and shaft 10. The lift arms 1L and 1R are rotated upward. A lift link is provided at the tip of the lift arm 1, and the lift link is pivotally connected to a part of the rotary tiller to move a working machine such as the rotary tiller up and down. The hydraulic system of the present invention constitutes a hydraulic control device that controls the position of the working machine, and can be controlled by two control methods: position control and depth control.

Position control controls the tractor's position so that the work equipment converges on the set position, and depth control controls the work equipment to always maintain the set distance from the ground regardless of the tractor's position. This is a control method that converges so that

In the case of rotary tillage equipment, depth control uses changes in plowing depth as a feedback signal that is fed back to the hydraulic system, but if this feedback signal is converted into traction force, it becomes draft control, and the traction force applied to the work equipment is always kept constant. It can be done.

Next, let me explain the flow of pressure oil in a hydraulic system.

In Figures 3 and 6, the lubricating oil in the transmission case is pressurized by a hydraulic pump installed in the engine in the bonnet of the agricultural tractor and is sent as hydraulic oil through a high-pressure pipe. 3
It enters the pressure oil port 3a shown in the figure.

This pressure oil port 3a is the relief valve 65 in FIG.
It communicates with the pressure oil chamber 3h below the pressure oil chamber 3h.
are the oil passage 3b to the ball valve 65a of the relief valve 65, the pressure oil outlet plug 68 on the side, the pressure oil outlet plug 69 on the front, and the oil pressure control valve 5 suspended on the bottom of the hydraulic case 2. It communicates with the oil passages 3i and 3d. Pressure oil is blown out from this relief valve 65 except when the control valve 5 is closed or when the piston is moved.

In addition, if a front loader or the like is attached to the front of the agricultural tractor without installing the work equipment at the rear of the agricultural tractor, and if there is a separate control valve for the work equipment, pressure can be supplied from the pressure oil outlets 68 and 69. The oil is extracted. The pressure oil spouted from the relief valve 65 enters the drain oil path 3c together with the pressure oil spouted from the safety valve 66.
It is returned to the mission case.

Further, the pressure oil that reaches the control valve 5 suspended from the bottom of the hydraulic case 2 from the oil passages 3i and 3d is controlled by the control valve 5, and the pressure oil returns to the cylinder head from the oil passage 3e, and then returns to the cylinder head through the oil passage 3e. 3
From j, it passes through 3f and enters the hydraulic cylinder 2a.

As shown in Fig. 5, a stop valve 4 is installed in the oil passage 3f.
When the spool 13 is fitted and the stop valve 4 is screwed in, the tip 4a pushes the spool 13 and closes the oil passage 3f, the pressure oil in the hydraulic cylinder 2a is no longer able to come out, and the lift arm is locked by hydraulic pressure. . In this case, if more pressure oil is sent, the relief valve 67 opens.

Reference numeral 70 denotes a hydraulic external outlet for taking out the pressure oil controlled by the control valve 5.

66 is a safety valve, and when abnormally high pressure occurs in the hydraulic cylinder 2a, the ball valve 66a of the safety valve 66 is pushed by the pressure oil discharged from the oil passage 3g communicating with the hydraulic cylinder, and the hydraulic pressure is increased. The pressure oil of the cylinder 2a is connected to the oil path 3.
g, it escapes to the drain oil path 3c.

The spool 6 of the control valve 5 has a spring 14
A longitudinal abutment pin 15 is fixed to the rear end of the spool 6.

Two valve control bars 11 and 12 are in contact with the rear surface of the contact pin 15. 11 is a valve control bar for position control, and 12 is a valve control bar for depth control.

When performing position control, rotate the position control setting lever 18 rearward to the desired position with respect to the traveling direction of the tractor, and when performing depth control, rotate the depth control setting lever 17 rearward. It is.

First, let me explain the case of position control.

When performing position control, the depth control setting lever 17 is rotated fully forward and fixed, and the depth control feedback arm 16 is also stopped at the fully forward rotation position as shown in Figure 2. 57 must be tightened and fixed in the elongated hole 57a with bolts 58. As a result, the control bar 12 for depth control is fixed at the rearmost position, and only the control bar 11 for position control touches the contact pin 15.

When the position control setting lever 18 is rotated to a desired position, the shaft 42 is rotated via the lever base 18a, lever boss 18b, and half-moon key 18c, and the arm 47 fixed to the inner end of the shaft 42 moves the pin 49. Through ball joint link 3
9 is pushed forward. The joint ball part 11b of the valve control bar 11 for position control is fitted into the ball fitting hole 39a at the tip of the ball joint link 39, and the roll pin 37 is designed to be free to rotate only back and forth.
and is pivotally supported in the ball fitting hole 39a. With this structure, the position control setting lever 18
As a result of the rearward rotation, the joint ball 11b side of the valve control bar 11 is pulled forward, the spool 6 is pushed forward by the contact pin 15, and the lift arms 1L, 1R are raised. Lift arm 1
The arm 33 is rotated from the joint 32 via the links 30a and 30, the shaft 34 is rotated by the boss 33a and the roll pin 33b, and the boss 35 is rotated.
a. The arm 35 rotates rearward, and the ball joint link 36 is lowered rearward by the pin 72.

Ball fitting hole 3 of ball joint link 36
6a, the other ball 11 on the control bar 11
A is loosely fitted, and by pushing this part backward, the control bar 11 retreats and the spool 6 is pushed by the spring 14 and returns to the neutral position. As a result, the position converges to the position set by the position control setting lever 18.

To lower the lift arm, simply rotate the position control setting lever forward, and the movement of the link described above will be reversed, and the lift arm will stop at the lower setting position.

With the position control device, the operator can simply rotate the setting lever to a predetermined position and then control the lift arm to the desired position without operating the setting lever or looking at the lift arm. Without this control device, you would have to move the lift arm with the hydraulic lever, and when the lift arm reaches the specified raised or lowered position, you would have to set the hydraulic lever to neutral and then let go of the hydraulic lever, which would be a hassle. It requires.

Next, let me explain the case of depth control.

When performing depth control, rotate the position control setting lever to a predetermined position and move the valve control bar 11 to the ball 11b.
Rotate it to the specified position using the section.

In parallel with this position control, the plowing depth is set by rotating the depth control setting lever 17.

By rotating the depth control setting lever 17, the cylinder shaft 41 is rotated via the lever base 17a, lever boss 17b, and half-moon key 17c, and the arm 4
8 and pushes the ball joint link 40 forward via the pin 50. This causes the ball 12b of the control bar 12, which is pivotally supported in the ball fitting hole 40a by the roll pin 38, to rotate forward.

On the other hand, the feedback of the plowing depth of the depth control is provided by a wire to the pin 19 or 20 of the depth control feedback arm 16.
can be conveyed to. This depth control feedback arm 16 is biased forward by a spring 21, but when the plowing depth becomes deeper, the rear cover is rotated significantly upward and the wire is pulled, causing the arm 16 to rotate rearward. The joint 23 and the links 24, 24a are pulled forward via the pivot shaft 22, and the boss 25a and half-moon key 25b are pulled forward from the arm 25.
The cylinder shaft 27 is rotated, the arm 28 is rotated forward, and the pin 71 and ball joint link 29 are rotated.
moves forward and moves the spool 6 in the upward direction. As a result, the lift arm 1 and
Working machines such as rotary tillers are also on the rise. The tilling depth then becomes shallower and converges at the set tilling depth. Conversely, if the plowing depth is shallow, control is performed in the opposite direction to lower the lift arm.

Control bars 11 and 12 both have balls 11a, 11b and 12 for ball joints.
a, 12b are provided, but one ball 1
Only on the 1b and 12b sides, the ball joint links 39 and 40 are pivotally supported by the roll pins 37 and 38 to prevent them from falling, and on the other side, the ball joint links 29 and 36
Balls 12a and 11a are loosely fitted in the holes to absorb changes in distance.

Also, the position control setting lever 18,
A depth control setting lever 17 is provided on the right side of the hydraulic case, a depth control feedback arm 16 and a position control feedback link device are provided on the left side, and both valve controls 11 and 12 are suspended from the bottom of the hydraulic case. The slide supports 51 and 52 shown in FIG. 9 are suspended from the lower surface of the hydraulic case so that the control bar can slide smoothly.

The slide support has an "L" shaped plate 51 and a "U" shaped plate 52 welded together to form two horizontal sliding surfaces, on which the control bars 11 and 12 are slidably held.

Similarly, the control valve 5 is also suspended from the bottom of the hydraulic case 2.

In addition, as shown in FIGS. 1, 3, and 8, in order to keep the height of the hydraulic case low, the rotation stopper 43 of the position control setting lever 18 and the depth control setting lever 17, and the pivot portion of the lever are provided. It has a compact structure.

A spacer 53 is provided so that the levers 17, 18, their shafts, cylinder shafts, etc. can be assembled separately from the hydraulic case 1, and are cantilevered by this spacer.Since this alone is weak, the shaft 42 is supported by two bolts 55, 54 and the clamping plates 44 and 60.

Further, the rotation stopper 43 is also fixed to the spacer 53.

First, from the inside of the spacer 53, the stepped cylindrical shaft 41
, insert the shaft 42 into it, fix the lever boss 17b to the part where the cylindrical shaft 41 protrudes from the spacer with a half-moon key, and then attach the flat washer and the pair of leaf springs 44.
Next, insert a pair of leaf springs 45 with the clamping plate 44 in between, then fix the lever boss 18c to the protrusion of the shaft 42 with a half-moon key, and then tighten the nut 60 and lock nut 61 with the clamping plate 60 in between. It is tightened to the extent that it does not kill the urging force of the leaf spring.

The clamping plates 44, 60 have two long bolts 55, 5
4, and the long bolts 55, 54 are locked at appropriate positions with lock nuts. The rotation stopper 43 is provided with a bent portion 43b bent into an L shape in order to match the size of the spacer 53, and a square hole 43a that communicates with the bent portion and the flat portion.
The setting levers 17 and 18 are rotatable only within the position 3a. The rotation stopper 43 has bolts 62, 6
3 to the spacer 53.

Depth control feedback arm 16
Two pins 19 and 20 are provided upright to support the wire end portions, and by adjusting the position of these pins, the amount of feedback can be adjusted.

Also, the threaded portion 24b of the link 24 and the joint 2
3 can also adjust the amount of feedback of the depth control.

Also, the feedback amount of the position control is determined by the threaded portion 30b of the link 30 and the joint 32.
It can be adjusted by

56 is an engagement bolt for the spring 21.

Draft control is achieved by connecting the depth control feedback arm with a wire from the traction force sensor.

As described above, the present invention provides a position control setting lever and a depth control setting lever concentrically on one side of the hydraulic case, and a depth control feedback device and a position control feedback link device on the other side of the hydraulic case. Valve control bars connecting the control system and feedback system of both control devices are placed vertically on the bottom of the hydraulic case, and a hydraulic control valve is suspended from the bottom of the hydraulic case and a vertical bar is placed on the tip of the spool. Since the two valve control bars are brought into contact with the top and bottom of the contact pins fixed in the direction, the pivot points of the control setting lever and the feedback arm can be placed apart from each other, and the control link part can be enlarged and ,
The valve control bar can be made longer and the accuracy of the control device can be increased. In addition, the two control setting levers are placed on one side, and the two sets of feedback devices are placed on the other side, allowing the hydraulic case to be lowered. Furthermore, the hydraulic control, which was conventionally placed inside the hydraulic case, can be lowered. The valve and valve control bar are suspended from the bottom of the hydraulic case and are visible inside the transmission case, so the hydraulic case itself can be lowered, and the control bar is placed inside the transmission case. The device has the effect of smoothing the movement of the links because the lubricating oil is splashed onto the links, valve control bars, etc.

[Brief explanation of the drawing]

Figure 1 is a right side view of the hydraulic control device of the present invention;
Figure 2 is a left side view, Figure 3 is a top view, Figure 4 is a bottom view, Figure 5 is A of Figure 3.
-A cross-sectional view as seen from the arrows, FIG. 6 is a BB--B cross-sectional view as seen in FIG. 5, FIG. 7 is a CC--C cross-sectional view as seen in FIG.
The figure is a sectional view taken along the line DD in FIG. 1, and FIG. 9 is a side view of the slide support of the valve control bar. 2... Hydraulic case, 5... Hydraulic control valve, 6... Spool, 11, 12... Valve control bar, 16... Depth control feedback arm, 17... Depth control setting lever, 18... Position Control setting lever, 30...Position control feedback link.

Claims (1)

[Scope of utility model registration request] A position control setting lever and a depth control setting lever are provided concentrically on one side of the hydraulic case, and a depth control feedback device and a position control feedback link device are provided concentrically on the other side of the hydraulic case. Valve control bars connecting the control system and feedback system of both control devices are placed vertically on the bottom of the hydraulic case, and the hydraulic control valve is suspended from the bottom of the hydraulic case and a connection is fixed vertically to the tip of the spool. A hydraulic control device for an agricultural tractor, characterized in that the two valve control bars are brought into contact with the top and bottom of the pin.