JPH0767323B2 - Working machine control mechanism of tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention is a work machine mounted on a tractor, such as a disk plow or a soil-repellent plate plow, towed by a large traction force so that the work machine can move in the soil. Draft control when pulling while receiving a large resistance to keep the pulling load constant, and when pulling the rotary tiller, depth control is used to keep the tilling depth constant. It is about.

(B) Conventional Technology Conventionally, there has been known a technology in which a position control link and a draft or depth control link are brought into contact with the operating end of a hydraulic control spool to perform control.

For example, it is like the technique described in Japanese Utility Model Laid-Open No. 59-31807.

(C) Problems to be Solved by the Invention However, in the above-mentioned conventional technique, in the position control, the draft and the depth control,
The operation slide width of the hydraulic control spool is the same, and in the case of draft and depth control, the amount of oil supplied to the hydraulic cylinder becomes excessive, and the extension operation of the hydraulic cylinder becomes too sensitive, causing chattering. It was.

Chattering phenomenon means, for example, when towing a draft working machine such as a disc plow, a soil-repellent plate plow, a disc harrow, a trencher or a box scraper.
The link system such as the draft spring 48 and the top link 49 vibrates at a high frequency.

This will be explained with reference to the soil-repellent plate plow in the towed state of the draft working machine in FIG.

When a traction force greater than the traction force set by the draft lever 21 acts on the soil-repellent plate plow, a compression force is generated in the top link 49, the sensor spring 48 of the top link sensor 43 is pulled, and the draft control link 1 operates, The control valve V switches, the soil repellent plate plow rises, the compression force of the top link 49 is released, and the soil repellent plate plow descends.

Therefore, if the vertical movement of the lift arm 44 is abrupt at this time or if there is looseness in the link of the draft control system at this time, the control valve V
Repeated ON-OFF, the soil-repellent plate plow does not rise, but the draft sensor spring 48 repeatedly compresses and opens, and a sound is generated by being hit by the link system.

This is the chattering phenomenon.

The present invention relates to a work implement control mechanism for a tractor,
It is configured to eliminate the chattering phenomenon.

(D) Means for Solving the Problem The object of the present invention is as described above, and the configuration for achieving the object will be described below.

In the hydraulic control spool 5 that can freely supply the oil amount to the hydraulic cylinder C from 0 to the set maximum amount, the position control allows the hydraulic control spool 5 to be slidable to a position where the set maximum amount can be supplied. In the control, the slide width of the hydraulic control spool 5 is regulated in a state before reaching the set maximum amount.

Further, in the hydraulic control spool 5 which can freely supply the oil amount to the hydraulic cylinder C from 0 to the set maximum amount, the position control allows the hydraulic control spool 5 to slide to a position where the set maximum amount can be supplied. In the depth control, the slide width of the hydraulic control spool 5 is regulated in a state before reaching the set maximum amount.

Further, when the slide width of the hydraulic control spool 5 is regulated, the feedback signal more than the slide amount is cut off before reaching the control link 1.

Further, the slide regulation amount of the hydraulic control spool 5 can be freely changed.

(E) Embodiment The purpose and constitution of the present invention are as described above. Next, the constitution of the embodiment shown in the accompanying drawings will be described.

FIG. 1 is a side view showing a draft control state with a soil-repellent plate plow 46 mounted, and FIG. 2 shows a position control and draft control mechanism for operating a control valve V attached to the lower surface of the hydraulic case 20. Rear sectional view, FIGS. 3 and 4 are side sectional views of the control valve V, FIG. 5 is a developed sectional view of each part of the control valve V, and FIG. 6 is a side sectional view of the control valve V, and FIG. Is a rear view of the control valve V, No. 8
The illustration shows draft feedback arm 25 and overcut spring
It is a perspective view of the portion of 50.

In FIGS. 1 and 8, the hydraulic case 20 is arranged above the rear axle case 47 of the tractor, and the pivot bracket 45 that pivotally supports the draft sensor 43 projects from the rear surface of the rear axle case 47. . The lower end of the draft sensor 43 is pivotally supported by the pivot bracket 45, and the upper end of the draft sensor 43 is supported via a draft sensor spring 48.

The soil repellent plate plow 46 can be moved up and down by the lift arm 44.

The draft sensor 43 transmits the change in traction force to the draft feedback arm 25 shown in FIG.

A sensor link 53 is pivotally connected to the draft sensor 43, and the tip of the sensor link 53 is slidable in a hollow cylinder 52 supported by a draft feedback arm 25.

An excess cut spring 50 is provided between the sensor link 53 and the hollow cylinder 52.
The draft sensor increases the towing load.
When 43 rotates, the sensor link 53 moves to the left in FIG. 1,
The draft feedback arm 25 is rotated via the excessive cut spring 50. When the contact body 11 comes into contact with the regulating body 8 to be described later, and the hydraulic control spool 5 cannot slide any more, pushing of the sensor link 53 by further rotation of the draft sensor 43 causes the excess cut spring to be pushed.
It can be absorbed by 50.

Next, the operating mechanism of the control valve V will be described with reference to FIG.

The hydraulic case 20 is mounted and fixed on the upper surface of the rear axle case 47, the hydraulic cylinder C is arranged in the center, and the control valve V is attached to the lower surface from below.

A draft lever 21 and a position lever 22 are arranged on the right side of the hydraulic case 20 so that the operator sitting on the seat can operate the right hand.

The rotation of the position lever 22 is transmitted to the arm 13 via the lever shaft 16, and the position control link 2 is pivotally supported at the lower end of the arm 13 via a ball joint 31.

Further, the vertical rotation amount of the lift arm 44 is transmitted to the position of the pin 27 as a position control feedback amount and is transmitted to the position feedback arm 23.

The rotation of the position feedback arm 23 is transmitted to the arm 15 via the feedback shaft 17,
The other end of the position control link 2 is pivotally supported via a ball joint 30 at the tip of 15.

As described above, at both ends of the position control link 2, the right side is the position lever 22 and the left side is the lift arm.
When the lift arm 44 reaches the position set by the position lever 22, the position control link 2 is in the neutral position, and the expansion and contraction of the hydraulic cylinder C is stopped at that position. ing.

Similarly, the draft lever 21 is interlocked with the arm 12 via the cylinder shaft 18, and is connected to the right end of the draft control link 1 by a ball joint 29 at the lower end of the arm 12.

Since the cylinder shaft 18 is loosely fitted to the outer periphery of the lever shaft 16, both can freely rotate.

Further, as disclosed in the description of the drawings of FIGS. 1 and 8, the rotation of the draft sensor 43 is transmitted to the hollow cylinder 52 of the draft feedback arm 25 via the sensor link 53.

The cylinder shaft 19 is loosely fitted to the outer periphery of the feedback shaft 17, and the cylinder shaft 19 is freely rotatable on the outer periphery of the feedback shaft 17.

The arm 14 fixed to the inner end of the cylinder shaft 19 supports the ball joint 28 at the other end of the draft control link 1.

With the configuration as described above, when the traction force is set by the draft lever 21, the change in the traction force is transmitted from the draft sensor 43 through the sensor link 53 to the other end of the draft control link 1 and set by the draft lever 21. The draft control link 1 is adjusted to return the hydraulic control spool 5 to the neutral position just when the traction force is reached.

According to the present invention having the above-described structure, the hydraulic control spool 5 is provided by the position control and the draft control.
The feature is that the slide amount of is changed.

The overall structure of the control valve V will be described with reference to FIG.

Pressure oil from a hydraulic pump P attached to the engine portion of the tractor is sent to the P port, and the pressure oil at the P port first passes through the unload valve 33. The unload valve 33 allows the pressure oil of the P port to flow into the front chamber and introduces the pressure oil of the P port into the back chamber at a position higher than the hydraulic control spool 5, so that the urging force of the urging spring 34 increases. The unload valve 33 is closed by the combined force. However, in the neutral and lowered positions, the pressure oil at the P port is unloading valve 33.
Since it is not introduced into the back chamber, the unload valve 33 is pushed to the right by the pressure of the P port against the spring force of the biasing spring 34, and the left end portion is opened, and the pressure oil of the P port is released from the valve case 9. It is discharged as drain oil into the rear axle case 47.

Further, the pressure oil of the P port is introduced into the front chamber of the flow control relief valve 41, while the pressure oil of the P port passing through the hydraulic control spool 5 is slid to the right in the drawing of the spool 5 to open its opening 5a. The pump pressure oil that has been opened is squeezed into the back chamber of the flow control relief valve 41 by opening the port 9 into the port 9.
Introduced via 55, the flow control relief valve 41 is biased by the bias spring 42 due to the differential pressure between the throttle portions of the hydraulic control spool.
It is constructed so as to open against the above, allow excess oil to escape to the tank, and adjust the amount of pressure oil reaching the raising check valve 39.

The raising check valve 39 is biased by a biasing spring 40,
It is in contact with the valve seat 43, and at the raised position of the hydraulic control spool 5, pressure oil opens the raising check valve 39, passes through the lowering check valve 37, and flows into the C port to the hydraulic cylinder C. .

Further, the lowering check valve 37 is biased by a biasing spring 38. When the hydraulic control spool 5 is pushed leftward by the lowering biasing spring 7 and the push rod 36 is pushed through the connecting rod 35, the lowering check valve 37 is checked. The valve 37 moves to the left against the biasing spring 38, the lowering check valve 37 is opened, and the pressure oil of the hydraulic cylinder C is discharged to the drain circuit.

The hydraulic control spool 5 is operated by the draft control link 1 and the position control link 2, which is the same as the conventional one. However, in the conventional art, the draft control link 1 and the position control link 2 are in contact with each other. Both are the same one contact pin, and this contact pin is integrated with the hydraulic control spool 5.

On the other hand, in the present invention, the draft contact pin 3 with which the draft control link 1 abuts and the position contact pin 4 with which the position control link 2 abuts are separately configured.

The position contact pin 4 with which the position control link 2 contacts the hydraulic control spool 5 as in the conventional case.
It is fixed to the spool rod 6 integrated with the spool rod 6. However, the draft contact pin 3 which is an essential part of the present invention is not directly integrated with the spool rod 6 and the spool rod 6 is It is fixed to the slide cylinder 11a loosely fitted to the outer periphery of the.

Since the slide cylinder 11a is in contact with the step portion of the spool rod 6, when the position contact pin 4 is pushed,
The spool rod 6 slides in the slide cylinder 11a, and when the draft contact pin 3 is pushed, the spool rod 6 slides via the slide cylinder 11a.

An abutment body 11 is projectingly provided on the slide cylinder 11a, and a pin at the tip of the regulating body 8 is inserted into a fitting hole of the abutment body 11.

Further, a contact engagement portion is formed in the restriction body 8, and the contact body 11 contacts the contact engagement portion to further slide the slide cylinder 11a in the right direction. This is impossible, and in this part, the excessive feedback amount based on the draft sensor 43 is regulated.

The restricting body 8 is screwed to the fixed screwing body 10, and the limit of the rightward movement of the draft contact pin 3 can be adjusted by loosening the lock nut 8a of the screwed portion. .

Therefore, the opening degree of the opening 5a of the hydraulic control spool 5 with respect to the port 9 can be changed.

The fixed screw body 10 is screwed and fixed to the valve case 9.

Next, referring to FIG. 3 and FIG.

FIG. 3 shows the state of the draft control. The arm 2 supporting the position control link 2 is rotated to the lowest position of the position lever 22, so that the position control link 2 is attached to the position contact pin 4. The draft control link 1 is moved to the right in the drawing and pushes the draft contact pin 3 when the draft sensor 43 rotates due to an increase in the traction load with respect to the setting operation of the traction load of the draft lever 21. The operating state is disclosed.

Since the abutment body 11 comes into contact with the regulation body 8 at the stroke t2, the opening 5a of the hydraulic control spool 5 is slightly opened with respect to the port 9, and the pump flow rate introduced into the hydraulic cylinder C is limited. To be done. Therefore, the extension speed of the hydraulic cylinder C becomes slow, the working machine slowly rises in the direction of reducing the towing load, and the chattering phenomenon is prevented from occurring.

When the work implement rises, the pulling force of the sensor spring 48 disappears, it contracts and rotates the draft sensor 43 counterclockwise,
The sensor rod 53 moves to the right and the spring force of the excess cut spring 50 is weakened, and the hydraulic pressure control spool 5 slides in the neutral direction by the downward bias spring 7 to balance the downward bias spring 7 and the excessive cut spring 50. At this point, the hydraulic control spool 5 is held in the neutral position, and the raising of the working machine is stopped.

FIG. 4 shows the position control, in which the draft lever 21 is rotated to the lowest position and the draft control link 1 is retracted. By operating the position lever 22 and rotating the lift arm 44, It is disclosed that the position control link 2 moves back and forth and the position contact pin 4 pushes the spool rod 6 and the hydraulic control spool 5 to extend the hydraulic cylinder C.

Since the hydraulic control spool 5 is free to slide at the stroke t1 until the stopper 6a of the spool rod 6 contacts the valve case, in the case of FIG. 4, the opening 5a is in the fully open position with respect to the port 9 and the pump flow rate Is supplied to the hydraulic cylinder C, and the working machine can be rapidly raised to an arbitrary position.

Incidentally, the present invention has shown the example adopted in the draft control as an embodiment, but if the working machine is a rotary tilling device, if the feedback signal is input to the draft feedback arm 25 by using the rear cover as a depth sensor as is well known. , Depth control can be performed.

FIG. 9 is a view showing another embodiment of the position contact pin 4 and the draft contact pin 23.

In this configuration, the draft contact pin 23 and the draft control link 1 are integrated, and the regulating body 8 that contacts the tip of the draft contact pin 23 is provided.

Further, the position contact pin 4 is extended downward and is loosely fitted in a long hole 23b opened in the draft contact pin 23.

With this configuration, the spool rod 6 can be eliminated, and only the spool 5 is required and the shape of the spool 5 can be simplified.

Further, as shown in FIG. 9, in the case of position control, the spool movement width on the lower side of the neutral position is 4 mm.
So, the moving width on the raising side is 12.5 mm, but in the case of draft control and depth control, the moving width on the raising side is restricted to 0.7 mm, although it is 4 mm on the lowering side. In this case, the opening 5a of the spool 5 is a narrow and narrow gap, and the flow rate to the hydraulic cylinder C is limited.

(F) Effects of the Invention The present invention having the above-described configuration has the following effects.

At the time of draft and depth control, the amount of oil supplied to the hydraulic cylinder C can be limited to a constant value by regulating the sliding amount of the hydraulic control spool 5, so that the chattering phenomenon caused by excessive control can be eliminated. Was made.

In addition, there is a range of the amount of oil in which the chattering phenomenon disappears depending on the type of the working machine, but the range in which the chattering phenomenon disappears can be searched for and the regulator 8 can be fixed at that position.

[Brief description of drawings]

FIG. 1 is a side view showing a draft control state with a soil-repellent plate plow 46 mounted, and FIG. 2 is a rear view showing a position control and draft control control mechanism for operating a control valve V attached to the lower surface of the hydraulic case 20. Sectional view, Fig. 3
4 is a side sectional view of the control valve V, FIG. 5 is a developed sectional view of each part of the control valve V, and FIG. 6 is the same control valve V.
7 is a rear sectional view of the control valve V, and FIG. 8 is a draft feedback arm 25 and an excessive cut spring 50.
FIG. 9 is a perspective view of a portion of FIG. V …… Control valve 1 …… Draft control link 2 …… Position control link 3 …… Draft contact pin 23 4 …… Position contact pin 5 …… Hydraulic control spool 6 …… Spool rod 7 …… Lower bias spring 8: Regulator 9: Valve case 10: Fixed screw body

Front page continuation (72) Inventor Jiro Shibata 2-18-1 Inadera, Amagasaki City, Hyogo Prefectural Kanzaki High-grade Machinery Works (72) Inventor Takashi Hashimoto 1-32 Chayamachi, Kita-ku, Osaka, Osaka Yanma -Diesel Co., Ltd. (72) Inventor, Kazuo Yamamoto 1-32, Chaya-cho, Kita-ku, Osaka City, Osaka Prefecture Yanma Diesel Co., Ltd. (56) References JP 59-88006 (JP, A) Actual Shou 59-77312 (JP, U)

Claims (4)

[Claims] 1. A hydraulic control spool 5 in which the amount of oil to be supplied to a hydraulic cylinder C can be arbitrarily supplied from 0 to a set maximum amount.
Can be slid to a position where the maximum set amount can be supplied, and in the draft control, the hydraulic control spool 5
A work implement control mechanism for a tractor, characterized in that the slide width is regulated in a state before reaching the set maximum amount. 2. A hydraulic control spool 5 in which the amount of oil to the hydraulic cylinder C can be arbitrarily supplied from 0 to a set maximum amount.
Is slidable to a position capable of supplying the set maximum amount, and in the depth control, the hydraulic control spool 5 is configured so that the slide width is regulated in a state before reaching the set maximum amount. Work machine control mechanism. 3. When the slide width of the hydraulic control spool 5 is regulated in claim (1) or (2), the feedback signal more than the slide amount is cut off before reaching the control link 1. A featured tractor work implement control mechanism. 4. A work implement control mechanism for a tractor according to claim 1 or 2, wherein the slide regulation amount of the hydraulic control spool 5 is changeable.