JP5280419B2 - Tractor work machine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a working implement controller of a tractor capable of effectively using a draft raising function. <P>SOLUTION: The traction load for raising a working implement can be set by adjusting the position of a pushing member relative to an abutting part by swinging a spool operating lever for a daft with one end side as a fulcrum. A draft feedback rod is pushed by a set traction load or larger than a set traction load to swing the draft spool operating lever with the other end side as a fulcrum and the abutting part is pushed by the pushing member to operate a spool so that the working implement is raised. When a lift arm is swung upward to the vicinity of the highest raised position when the working implement is raised by a draft operating means, the draft spool operating lever is swung with the other end side as a fulcrum by a rising restraining link in such a direction that the pushing member is separated from the abutting part and the draft feedback rod is contracted to permit the swing, so that the rising motion of the lift arm is stopped. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a tractor work machine control device that performs draft control of a work machine that is mounted on a rear part of a tractor so as to be movable up and down.

Conventionally, as a work machine control device for a tractor, a single control valve is used to perform position control and draft control of a work machine mounted on a rear part of a tractor so as to be movable up and down. Has been.
In the one described in Patent Document 1, a three-point link mechanism for mounting a work implement to be movable up and down is provided at the rear part of the vehicle body of the tractor, and a pair of left and right lift arms is provided on a casing provided on the rear part of the vehicle body of the tractor And a lifting cylinder composed of a hydraulic cylinder that swings the left and right lift arms up and down is provided at the rear of the tractor body. The left and right lift arms are connected to a lower link via a lift rod, and pressure oil is supplied to the lifting cylinder. When the lift cylinder is extended and the lift cylinder is extended, the lift arm swings upward to raise the work implement. By discharging the pressure oil from the lift cylinder, the lift arm swings downward and the work implement is lowered by its own weight. Is configured to do.

The casing is provided with a control valve for switching the flow of pressure oil to the elevating cylinder, and a position spool operating lever and a draft spool operating lever for operating a spool of the control valve.
The control valve is configured to switch the flow of pressure oil so that the lift cylinder extends when the spool is pushed from the neutral position and the lift cylinder contracts when the spool is pulled from the neutral position.

The position spool operating lever is connected to the spool of the control valve at the intermediate portion, and the position spool operating lever is configured to swing with one end as a fulcrum by the operation of the position operating lever operated by the operator. Has been.
Then, by swinging the position spool operating lever with one end side as a fulcrum by the position operating lever, when the spool of the control valve is pushed or pulled out from the neutral position, the lift arm swings upward or downward.

When the lift arm swings, the position spool operating lever is swing-operated with the other end side as a fulcrum by a position feedback rod pivotally connected to the lift arm, thereby returning the spool of the control valve to the neutral position. When the spool returns to the neutral position, the lifting operation of the work machine stops.
Accordingly, the work implement is raised and lowered in proportion to the swing operation amount of the position operation lever, and the work implement can be held at an arbitrary height position suitable for work.

The draft spool operating lever is configured to be swung with one end side as a fulcrum by a swinging operation of a draft operating lever operated by an operator.
The draft spool operating lever is provided with a draft joint block at an intermediate portion.
Then, when the draft operation lever is swung to swing the draft spool operating lever with one end side as a fulcrum, the draft joint block comes close to the contact portion provided on the spool side of the control valve. It is configured to move in the separating direction.

On the other hand, a top link mounting bracket for mounting the front end side of the top link is mounted on the rear portion of the tractor body via a torsion bar. This top link mounting bracket is connected to one end of a draft spool operating lever via a draft feedback rod. Linked to the side.
When a traction load is applied to the work implement, a compressive force is applied to the top link, and the top link mounting bracket is pressed by the top link and the torsion bar is twisted, so that the top link mounting bracket presses the draft feedback rod. Move.

When the draft feedback rod is pushed, the draft spool operating lever swings with the other end side as a fulcrum, and the draft joint block moves in a direction approaching the spool side contact portion.
When an excessive traction load (greater than the set load) acts on the work implement, the draft joint block comes into contact with the contact portion and pushes it. Then, the spool is pushed in from the neutral position, the work implement is raised, and the traction load acting on the work implement is reduced.

In other words, the work implement is raised by a work implement raising command from the draft feedback rod.
When the excessive traction load acting on the work equipment is released, the restoring force of the torsion bar moves the top link mounting bracket back to its original position, and the draft joint block moves away from the spool side contact part. Thus, the draft spool operating lever swings around the other end side as a fulcrum.

Thereafter, the work implement is lowered to the position set by the position operation lever by the position control operation described above.
In the case of the above-described configuration, the closer the draft joint block is to the contact portion, the more sensitive the draft sensitivity (the degree to which a traction load higher than the setting is sensed) becomes, and the draft joint block is removed from the contact portion. The draft sensitivity becomes insensitive when moved away.

JP 2006-333741 A

In the conventional tractor work machine control device, the draft spool operating lever is swung around one end as a fulcrum so as to operate the draft operating means and push the contact portion by the pushing member to push the spool. By doing so, the work implement can be forcibly raised (drafted up) by swinging the lift arm upward.
However, in this case, in the conventional tractor work machine control device, the work machine raising operation cannot be stopped unless the work machine raising command from the draft operation means is canceled, so the draft up function cannot be used effectively. There is a problem.

  In view of the above problems, the present invention makes it possible to adjust the draft sensitivity by swinging the draft spool operating lever with one end side as a fulcrum by the draft operating means, and to set the draft spool by a traction load exceeding the setting. In a tractor work machine control device in which a lift arm is lifted by pushing a spool by swinging an operation lever with the other end as a fulcrum, a tractor capable of effectively using a draft up function It is an object to provide a work machine control device.

The technical means taken by the present invention to solve the technical problem is that the invention according to claim 1 is a lift arm for raising and lowering a working machine mounted on a vehicle body in a casing provided on the rear part of the vehicle body. Is provided so that the lift arm can swing up and down, a control valve that switches the flow of pressure oil to the lift cylinder inside the casing, and a draft spool that operates the spool of the control valve A load sensing member for detecting a load acting on the work machine at one side of the casing, the swinging lever for the draft being freely swingable about one end as a fulcrum by a draft operation means; A draft feedback rod that is linked to the other end and linked to the other end of the draft actuating lever is provided. When the traction load is applied, the draft feedback rod is pushed from the load sensing member side to one end of the draft actuating lever so that the draft actuating lever swings with the other end as a fulcrum and actuates for drafting The pushing member provided on the lever pushes the contact portion provided on the spool side to operate the spool so as to raise the work implement, and the draft spool operating lever is swung around one end side as a fulcrum. In the tractor work machine control device that can set the traction load to raise the work machine by adjusting the position of the pushing member with respect to the contact part,
An ascending restriction link having one end side linked to the lift arm and the other end linked to the other end side of the draft feedback rod is provided, and the draft operating means forcibly pushes the contact portion by a pushing member. When the drafting operation means is operated so that the contact portion is forcibly pushed by the pushing member, the lift arm is near the highest position. When the upper arm is swung upward, the draft spool actuating lever is swung in the direction away from the contact portion with the other end side as a fulcrum by the ascending restriction link so as to stop the lifting operation of the lift arm. The length of the draft feedback rod is shortened so as to allow the above.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, a draft feedback shaft that penetrates the casing and is rotatably supported around the shaft center is provided. A draft feedback arm connected to one end side of the draft spool operating lever is provided on the inner end side of the shaft, and the other end side of the draft feedback rod is connected to the outer end side of the draft feedback shaft via a connecting pin. A connecting arm is provided, and an engaging plate having an engaging hole through which the connecting pin is inserted is provided on the other end side of the ascending restriction link. The engaging hole is formed in a long hole shape, and the lift arm is at its highest position. The connection pin moves in the engagement hole until it reaches the position, and when the lift arm reaches the highest position, the connection pin is pulled at the end of the engagement hole. As a result, the draft feedback shaft rotates through the draft connecting arm, and the draft feedback shaft rotates through the draft feedback arm, so that the draft spool operating lever is brought into contact with the pushing member with the other end as a fulcrum. It is comprised so that it may rock | fluctuate in the direction away from.

  In addition to the configuration of the invention of claim 1 or 2, the draft feedback rod includes a main body rod constituting one end in the length direction and a cylinder constituting the other end in the length direction. A member, a spring receiving member fixed to the other end in the length direction of the main body rod and inserted into the cylindrical member, a spring receiving member provided in a fixed manner on the other end in the length direction in the cylindrical member, It is mainly comprised from the spring member interposed by compression between the said spring receiving members, The length is shrink | contracted when the said spring member shrinks, It is characterized by the above-mentioned.

According to the first aspect of the present invention, when the draft spool operating lever is swung about one end side as a fulcrum by the draft operation means and the spool is forcibly pushed, the lift arm swings upward and the working machine is lifted. To do.
When the lift arm rises to the vicinity of the highest position, the drafting spool operating lever is swung in the direction away from the contact portion with the other end side as a fulcrum by the ascent restriction link, and this is allowed. By shortening the length of the draft feedback rod, the work implement raising command by the draft operation lever is canceled, and the lifting operation of the lift arm is stopped. This makes it possible to use the draft up function effectively.

According to the second aspect of the present invention, since the connecting pin moves in the engagement hole until the lift arm reaches the vicinity of the highest lift position, the lift restriction link does not hinder draft control.
According to the invention which concerns on Claim 3, a draft feedback rod can be assembled easily.

It is a side view of the rear upper part of a tractor vehicle body. It is front sectional drawing of a working machine control apparatus. It is a plane schematic block diagram of a working machine control apparatus. It is a side view of the principal part. It is a top view of the principal part. It is the top view and side view of the rear part of a draft feedback rod. It is a side view of the principal part at the time of sensing load. It is a side view of the principal part when a lift arm rocks upwards in the vicinity of the raised position. It is front sectional drawing of the center side of a working machine control apparatus. It is front sectional drawing of the right side of a working machine control apparatus. (A) is the figure which looked at the linkage part etc. of a draft 1st relay arm and a draft 2nd relay arm from the right side, (b) and (c) are the linkage parts of a position 1st relay arm and a position 2nd relay arm. It is the figure which looked at from the right side. (A) is a top view which shows a control valve, a spool, a position spool operating lever, and a draft spool operating lever, and (b) is a side partial sectional view showing a control valve, a spool and a lever connecting portion.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a mission case that constitutes the rear part of the tractor body, and is attached to the upper surface side of the mission case 1 so as to cover an opening formed on the upper surface of the mission case 1. A casing 2 is provided.
The vehicle body of the tractor mainly includes a front engine, a clutch housing connected to the rear part of the engine via a flywheel housing, and a transmission case 1 connected to the rear part of the clutch housing.

  The casing 2 is formed in a downward opening shape, and a bracket mounting portion 4 for mounting the top link mounting bracket 3 is provided at the rear portion of the casing 2, and the bracket mounting portion 4 has a lateral axis. A top link mounting bracket 3 is mounted via a bar (load sensing member) 5, and one end side (tractor side) of the top link of the three-point link mechanism is installed in one of the mounting holes 6 provided in the top link mounting bracket 3. Are selectively pivotally connected.

One end side (tractor side) of the left and right lower links of the three-point link mechanism is pivotally connected to a lower link mounting portion provided at the rear lower part of the side surface of the mission case 1, and the other end side of the top link and left and right lower links (work The machine side) is pivotally connected to a frame of a work machine such as a plow, and the work machine is mounted on the rear part of the vehicle body 1 of the tractor so as to be raised and lowered via a three-point link mechanism.
Lift arm pivots 7 are provided in the front-rear halfway part (front side of the bracket mounting part 4) of the left and right side surfaces of the casing 2, and the base 8a of the lift arm 8 is disposed in the left and right lift arms pivots 7 in the left-right direction. It is pivotally supported so as to be rotatable around the axis X.

One end side of the lift rod is pivotally connected to the distal end side 8b of the left and right lift arms 8, and the other end side of each of the left and right lift rods is pivotally connected to the middle portion in the longitudinal direction of the lower link located on the same side in the left-right direction. Is done.
In addition, a pair of left and right lifting cylinders 9 are arranged on the rear side of the mission case 1, and one end side (upper end side, piston rod) of the left and right lifting cylinders 9 is pivotally connected to the middle part of the left and right lift arms 8. The other end side (lower end side, piston top side of the cylinder body) of the cylinder 9 is pivotally connected to a cylinder mounting portion provided at the rear lower portion of the side surface of the transmission case 1.

The left and right lift arms 8 swing up and down around the rotation axis X by extending and retracting the left and right lift cylinders 9 (projecting and retracting the piston rod). When the left and right lift arms 8 swing up and down, the left and right lower links swing up and down around the pivot on the tractor side, whereby the work implement is raised and lowered.
The elevating cylinder 9 is constituted by a single-acting hydraulic cylinder, and pressure oil is supplied to the piston top side of the cylinder body of the elevating cylinder 9 so that the piston rod protrudes upward (the elevating cylinder 9 is extended). Thus, the lift arm 8 is rotated upward to raise the work implement, discharge the pressure oil on the piston top side of the cylinder body of the lift cylinder 9 and retract the piston rod downward (the lift cylinder 9 contracts). ), The lift arm 8 is rotated downward and the work implement is lowered by its own weight, and the lift arm 8 is stopped and the work implement is stopped by stopping the supply and discharge of the pressure oil to the lift cylinder 9. Has been.

The casing 2, the lift arm 8, the lift rod, the lifting cylinder 9, etc. mainly constitute a hydraulic lifting device 10 that lifts and lowers the work implement.
A control valve 11 for controlling the elevating cylinder 9 is disposed at the front part inside the casing 2.
The control valve 11 is constituted by a direct-acting spool type three-position switching valve, and is provided so that the spool 12 protrudes forward and is slidable in the front-rear direction.

  When the spool 12 of the control valve 11 slides in the front-rear direction, the pressure oil is supplied to the neutral position where supply / discharge of the pressure oil to the lifting cylinder 9 is stopped and to the piston top side of the cylinder body of the lifting cylinder 9. The spool 12 is switched between an ascending position and a descending position where pressure oil is discharged from the piston top side of the cylinder body of the elevating cylinder 9 (the control valve 11 is switched between a neutral position, an ascending position, and a descending position). .

Further, the spool 12 is urged by a spring S shown in FIG. 12 in a direction to switch the control valve 11 so as to lower the work implement (contract the elevating cylinder 9 or rotate the lift arm 8 downward).
In the present embodiment, the control valve 11 is switched so as to raise the working machine by pushing the spool 12 from the neutral position (the spool 12 is switched to the raised position), and the working machine is pulled out from the neutral position. The control valve 11 is switched so as to lower (the spool 12 is switched to the lowered position). Therefore, the spool 12 is biased in the direction of being pulled out by the biasing force F of the spring S.

  As shown in FIGS. 1, 2, 9, and 12, an attachment member 13 is attached and fixed to the front end side (front end side) of the spool 12 of the control valve 11. A support member 14 composed of, for example, is fixed. The support member 14 protrudes downward from the tip of the spool 12, and a pair of upper and lower support shafts 16, 17 having an axial center in the front-rear direction on the front side of the support member 14. Is provided so as to protrude forward.

The upper support shaft 16 is provided concentrically with the shaft center of the spool 12, and the position joint block 18 is rotatable about the shaft center and cannot move in the axial direction (front-rear direction). Is externally fitted. A position joint pin 19 having a vertical axis is fixed to the upper surface side of the position joint block 18.
The lower support shaft 17 is provided at a position directly below the upper support shaft 16 in parallel with the upper support shaft 16, and a draft joint block (pushing member) 20 is attached to the lower support shaft 17. It is externally fitted so as to be rotatable around the center and movable in the axial direction (front-rear direction). A draft joint pin 21 having a vertical axis is fixed to the lower surface side of the draft joint block 20.

The position coupling pin 19 is pivotally connected to an axially intermediate portion of a position spool operating lever 22 arranged in the left-right direction, and the left and right sides of the position spool operating lever 22 are positioned on the position joint pin 19. A position spool operating lever 22 is supported so as to be swingable back and forth and swing up and down.
The draft joint pin 21 is pivotally connected to an axially midway portion of a draft spool operating lever 23 arranged in the left-right direction, and both left and right sides of the draft spool operating lever 23 are draft joint pins. A draft spool actuating lever 23 is supported so that it can swing back and forth about 21 and swing up and down.

Ball joint portions 22a and 23a are provided at both ends in the left and right direction (axial direction) of the position spool operating lever 22 and the draft spool operating lever 23, respectively.
A position operation shaft 24 and a draft operation shaft 25 are disposed on the left and right sides (right side) of the front end side of the spool 12 of the control valve 11, and both the position operation shaft 24 and the draft operation shaft 25 are arranged in the left-right direction. Has an axis.

The draft operating shaft 25 is formed of a cylindrical body, and is inserted into a support hole 26 formed through the right wall of the casing 2 in the left-right direction, and is supported by the support hole 26 so as to be rotatable about its axis. Has been.
The position operating shaft 24 is inserted concentrically with the draft operating shaft 25 and is supported by the draft operating shaft 25 so as to be relatively rotatable about the axis.

A left and right inner end of the draft operating shaft 25 protrudes from the support hole 26 in the left and right direction, and a draft operating arm 27 protruding downward in the radial direction is fixed to the left and right inner end of the draft operating shaft 25. The leading end side (protruding end portion side) of the draft operating arm 27 is linked to the ball joint portion 23a on the right end side of the draft spool operating lever 23 through a ball joint structure.

In addition, the left and right outer end sides of the draft operating shaft 25 protrude from the support hole 26 in the left and right directions, and the first first relay arm of the draft operating shaft 25 protrudes radially upward at the left and right outer end sides. 28 is fixed, and an engagement pin 29 having a left and right axial center is fixed to the front end side (projecting end portion side) of the draft first relay arm 28 so as to project outward in the left and right direction.
The inner side of the position operating shaft 24 in the left-right direction protrudes from the draft operating shaft 25 in the left-right direction, and the position operating arm 31 that protrudes radially upward is fixed to the inner side of the position operating shaft 24 in the left-right direction. The front end side (protruding end portion side) of the position operating arm 31 is interlocked and connected to the right end side ball joint portion 22a of the position spool operating lever 22 by a ball joint structure.

The left and right outer ends of the position operating shaft 24 protrude in the left and right directions from the draft operating shaft 25, and a boss 32 is attached and fixed to the left and right outer ends of the position operating shaft 24. The position first relay arm 33 is fixed so as to protrude upward in the direction.
As shown in FIGS. 2 and 9, a position relay shaft 34 having a horizontal axis is concentrically arranged on the right side of the position operation shaft 24 and the draft operation shaft 25, and above the position relay shaft 34. A draft relay shaft 35 having a horizontal axis is arranged in parallel.

The position relay shaft 34 and the draft relay shaft 35 are attached to an attachment frame 36 that is detachably attached and fixed to the right side portion of the casing 2 by bolts, and are supported so as to be rotatable about an axis.
The mounting frame 36 includes a main frame 37 that is bolted to the casing 2 and a pair of upper and lower support cylinders 38. The main frame 37 includes inner and outer walls 37a and 37b that are opposed to each other with a space in the left-right direction. The inner wall 37a and the outer wall 37b are formed in a U shape in a plan view from a rear wall 37c that connects the rear edge sides of the outer wall 37b.

  An insertion portion 43 for inserting the draft operating shaft 25 is formed at the lower portion of the inner wall 37a of the main frame 37, and the insertion portion 43 is formed by an open U-shaped cutout portion below. The insertion portion 43 is externally fitted to the draft operation shaft 25 from above so that the draft operation shaft 25 can be inserted into the inner wall 37a of the main frame 37.

The upper and lower support cylinders 38 have a horizontal axis, and the inner end side in the left and right direction is fixed to the outer surface side of the outer wall 37 b of the main frame 37. A stopper plate 44 is fixed to the front.
A draft relay shaft 35 is inserted through the upper support cylinder 38 through the stopper plate 44, and the inner side in the left-right direction of the draft relay shaft 35 penetrates the outer wall 37 b of the main frame 37 and The draft second relay arm 46 is fixed to the boss 45 that is externally fitted and fixed to the protruding portion on the radially outer side and the lower side of the outer side wall 37b.

The lower side of the draft second relay arm 46 is, as shown in FIG. 11A, a bifurcated fitting portion that is fitted (engaged) from above with the engagement pin 29 of the draft first relay arm 28. The draft second relay arm 46 is interlocked and connected to the draft first relay arm 28 by fitting the fitting portion 46a to the engagement pin 29 from above.
A position relay shaft 34 is inserted into the lower support cylinder 38 through the stopper plate 44, and the inner end side in the left-right direction of the position relay shaft 34 passes through the outer wall 37 b of the main frame 37. The position second relay arm 48 is fixed to the boss 47 that is externally fitted and fixed to the protruding portion so as to protrude upward on the radially outer side.

As shown in FIGS. 11B and 11C, the position second relay arm 48 includes an arm main body 48A located on the side of the position first relay arm 33, and a laterally inner side from the arm main body 48A. And a pushing portion 48B that is fixed in a protruding manner and is capable of pushing the position first relay arm 33 from the front side and pushing it.
The position relay shaft 34 and the draft relay shaft 35 protrude outward in the left-right direction from the stopper plate 44, and mounting plates 49, 50 are fixed to the protruding portions of the relay shafts 34, 35.

A position relay lever 51 is fixed to the mounting plate 49 fixed to the position relay shaft 34, and a draft relay lever 52 is fixed to the mounting plate 50 fixed to the draft relay shaft 35.
A position operation lever 53 as a position operation means operated by an operator is linked to the position relay lever 51 via a joint, a rod, etc., and the draft relay lever 52 is used as a draft operation means operated by an operator. A draft operation lever 54 is interlocked and connected via a rod or the like.

The position operation lever 53 and the draft operation lever 54 are supported by a common lever support shaft 55 so as to be swingable up and down (back and forth swingable) around the left and right axes.
A spring receiving plate 56 is disposed on the outer side of each mounting plate 49, 50 in the left-right direction, and the draft relay shaft 35 and the position relay shaft 34 pass through the spring receiving plate 56. A friction plate 57 is interposed between the stopper plate 44 and the mounting plates 49 and 50 and the spring receiving plate 56.

Further, a pressure plate 62 is disposed on the side of the spring receiving plate 56 at an interval, and the position relay shaft 34 and the draft relay shaft 35 pass through the pressure plate 62, and the pressure plate 62 and the spring receiving plate A compression coil spring 58 fitted to the draft relay shaft 35 and the position relay shaft 34 is interposed between the relay relay shaft 56 and the position relay shaft 34.
A pair of front and rear bolts (not shown) pass through the pressure plate 62, the spring receiving plate 56, and the stopper plate 44, and the inner ends of the bolts in the left-right direction are screwed into a fixing nut 60 fixed to the stopper plate 44. A tightening nut (not shown) is screwed onto the outer end of each bolt in the left-right direction. By tightening the tightening nut, a predetermined operation resistance is applied to the draft relay shaft 35 or the position relay shaft 34. It is comprised so that.

  In the present embodiment, the attachment frame 36 is attached to the casing 2 (the tractor vehicle body side) with the position relay shaft 34, the draft relay shaft 35, the attachment plates 49, 50, etc. assembled to the attachment frame 36. Thus, the position second relay arm 48 is engaged with the position first relay arm 33 and the draft second relay arm 46 is engaged with the draft first relay arm 28.

A position feedback shaft 66 and a draft feedback shaft 67 are arranged on the left and right other side (left side) of the front end side of the spool 12 of the control valve 11. Both the position feedback shaft 66 and the draft feedback shaft 67 are arranged in the left-right direction. Has an axis.
The draft feedback shaft 67 is formed of a cylindrical body, is inserted through a support hole 68 formed through the left wall portion of the casing 2 in the left-right direction, and is rotatable about the shaft center in the support hole 68. It is supported.

The position feedback shaft 66 is inserted through a draft feedback shaft 67 and is supported by the draft feedback shaft 67 so as to be relatively rotatable about the axis. The position feedback shaft 66 and the draft feedback shaft 67 are arranged concentrically. Has been.
The inner side of the draft feedback shaft 67 in the left-right direction protrudes from the support hole 68 in the left-right direction, and a draft feedback arm 69 protruding downward in the radial direction is fixed to the inner end of the draft feedback shaft 67 in the left-right direction. The leading end side (projecting end portion side) of the draft feedback arm 69 is interlocked and connected to the ball joint portion 23a on the left end side of the draft spool operating lever 23 by a ball joint structure.

Further, the left and right outer end sides of the draft feedback shaft 67 protrude from the support hole 68 in the left and right directions, and the draft connecting arm 70 protrudes radially upward from the left and right outer end sides of the draft feedback shaft 67. It is fixed.
As shown in FIGS. 2, 4, and 5, the side of the casing 2 on the side from which the position feedback shaft 66 and the draft feedback shaft 67 project (left side) is inclined so as to move upward as going backward. An arranged draft feedback rod 71 is provided.

The front end side (one end side) of the draft feedback rod 71 in the length direction is pivotally connected to the front end side of the draft connecting arm 70, and the rear end side (the other end side) of the draft feedback rod 71 in the length direction is It is pivotally connected to a mounting bracket 72 fixed to the top link mounting bracket 3.
The draft feedback rod 71 is fixed to a main body rod 81 constituting one end in the length direction, a cylinder member 82 constituting the other end in the length direction, and the other end in the length direction of the main body rod 81. A spring receiving member 83 inserted into the member 82, a spring receiving member 84 fixedly provided at the other end in the longitudinal direction in the cylindrical member 82, and the spring receiving members 83, 84 are compressed. It is mainly composed of a mounted spring member 85.

  The draft feedback rod 71 will be described in detail. As shown in FIGS. 4 and 6, the draft feedback rod 71 is pivoted via a connecting pin 79 whose front end in the axial direction has a horizontal axis on the front end side of the draft connecting arm 70. A main body rod 81 that is connected to the support, a cylindrical member 82 that is pivotally connected to the mounting bracket 72 via a connecting pin 80 that has a left and right axial center on the rear end side in the axial direction, and a rear end side of the main body rod 81. A front spring receiving member 83 that is fixed and inserted into the cylindrical member 82 from the front end side, a rear spring receiving member 84 that is fixedly provided on the rear side in the cylindrical member 82, a front spring receiving member 83, and a rear spring It is mainly composed of a spring member 85 made of a coil spring interposed in compression between the receiving member 84.

The main body rod 81 is configured to be adjustable in length by a turnbuckle structure.
In the present embodiment, a connecting plate 91 is fixed to the front end side of the main body rod 81, and the connecting pin 79 penetrates the connecting plate 91 and the leading end side of the draft connecting arm 70 in the left-right direction. The front end side of the main body rod 81 is pivotally connected to the draft connection arm 70 so as to be rotatable about the left and right axis.

The cylindrical member 82 is formed in a cylindrical shape, and a long pin-like pin insertion hole 86 is formed in the axial direction (the length direction of the draft feedback rod 71) on both the left and right sides of the front part. A pair of upper and lower cutouts 87 formed in the center direction are formed.
A main body portion 83a of the front spring receiving member 83 is formed in a columnar shape and is slidable in the axial direction in the cylindrical member 82. A pin 88 is provided in the left and right direction on the main body portion 83a of the front spring receiving member 83. It is provided in a penetrating manner, and the pin 88 is inserted through the pin insertion hole 86 provided in the front portion of the cylindrical member 82.

Therefore, the front spring receiving member 83 is movable in the range from one end side to the other end side in the longitudinal direction of the pin insertion hole 86, and the draft feedback rod 71 is configured so that the front spring receiving member 83 is urged by the urging force of the spring member 85. The length is reduced by moving backwards against it.
The rear spring receiving member 84 is constituted by a pin that penetrates the cylindrical member 82, and a seat plate 89 is provided between the rear spring receiving member 84 and the spring member 85.

The front side of the mounting bracket 72 is inserted into the upper and lower cutouts 87 formed in the rear portion of the cylindrical member 82, and the connecting pin 80 penetrates the mounting bracket 72 and the cylindrical member 82. The rear part of the member 82 is pivotally connected to the front part of the mounting bracket 72 so as to be rotatable about the left and right axis.
The draft feedback shaft 67, the draft feedback arm 69, the draft connecting arm 70, the draft feedback rod 71 and the like constitute a draft feedback mechanism.

Note that the draft feedback rod 71 is not limited to the one having the above-described configuration, and a spring member that is elastic in the length direction is interposed in the middle in the length direction, and the length of the draft feedback rod 71 is reduced by contraction of the spring member. Any structure that shrinks may be used.
The position feedback shaft 66 protrudes from the draft feedback shaft 67 in the left-right direction, and a position feedback arm 74 that protrudes radially upward is fixed to the position feedback shaft 66 in the left-right direction inner end. The front end side (protruding end portion side) of the position feedback arm 74 is interlocked and connected to the ball joint portion 22a on the left end side of the position spool operating lever 22 by a ball joint structure.

The left and right outer ends of the position feedback shaft 66 protrude from the draft feedback shaft 67 in the left and right directions, and a boss 75 is attached and fixed to the left and right outer ends of the position feedback shaft 66. A position connecting arm 76 is fixed in a projecting manner on the lower side in the direction.
As shown in FIGS. 2, 4, and 5, the side of the casing 2 on the side from which the position feedback shaft 66 and the draft feedback shaft 67 project (left side) moves upward as it goes rearward in a side view. A position feedback rod 77 arranged in an inclined manner is provided.

The front end side (one end side) in the length direction of the position feedback rod 77 is pivotally connected to the front end side of the position connecting arm 76, and the rear end side (the other end side) in the length direction of the position feedback rod 77 is The lift arm 8 is pivotally connected to a pivot support portion 78 provided on the lower side of the base portion 8a.
The position feedback rod 77 is adjustable in length by a turnbuckle structure.

In the present embodiment, the rear end side of the position feedback rod 77 is a pivot portion 77a bent inward in the left-right direction, and this pivot portion 77a penetrates the pivot connection portion 78 in the left-right direction. The rear end side of the position feedback rod 77 is pivotally connected to the pivot connecting portion 78 so as to be rotatable about the left and right axis.
The position feedback shaft 66, the position feedback arm 74, the position connecting arm 76, the position feedback rod 77 and the like constitute a position feedback mechanism.

As described above, the closer the draft joint block 20 is to the support member 14, the more sensitive the draft sensitivity (the degree to which a traction load higher than the setting is sensed), and the more the draft joint block 20 is moved away from the support member 14. The draft sensitivity becomes insensitive.
As shown in FIGS. 2, 4, and 5, on the side (left side) of the casing 2 on the side from which the position feedback shaft 66 and the draft feedback shaft 67 protrude, the ascending restriction link 93 extends along the front-rear direction. Are arranged.

The rear end side (one end side) of the ascent regulating link 93 is interlocked with the lift arm 8, and the front end side (the other end side) of the ascent regulating link 93 is interlocked with the front end side (connecting pin 79) of the draft feedback rod 71. Has been.
The ascending restriction link 93 is mainly composed of a link main body 94 and an engagement plate 95 fixed to the front end side of the link main body 94.

Further, the ascent restriction link 93 is disposed between the draft feedback rod 71 and the position feedback rod 77 in the left-right direction.
A boss 96 is provided on the rear end side of the link body 94, and an intermediate part of the link body 94 is adjustable in length by a turnbuckle structure.
On the other hand, the pivot portion 77a on the rear end side of the position feedback rod 77 protrudes inward in the left-right direction from the pivot connection portion 78, and a boss 96 on the rear end side of the link body 94 extends in the left-right direction at this protruding portion. It is pivotally supported so as to be rotatable around its axis.

The engagement plate 95 is formed in a rectangular shape that is long in the front-rear direction in a side view, and the engagement plate 95 is formed with a long-hole-like engagement hole 97 in the longitudinal direction.
A connecting pin 79 that pivotally connects the front end side of the draft feedback rod 71 to the draft connecting arm 70 is inserted into the engaging hole 97 so as to be movable in the longitudinal direction.
In the work machine control apparatus that performs position control and / or draft control of the work machine having the above-described configuration, first, a case where position control (position control) is performed will be described.

When position control is performed, the draft joint block 20 is moved forward by operating the draft control lever 54 so that the draft joint block 20 does not interfere with the pushing of the spool 12 from the neutral position. Thus, a sufficient space is provided between the draft joint block 20 and the support member 14.
When the work implement mounted on the tractor is stopped between the upper limit and the lower limit, that is, when the spool 12 is in the neutral position, the position operation lever 53 is moved upward (or rearward). (Position), the position second relay arm 48 is rotated rearward via the position relay lever 51 and the position relay shaft 34, and the pushing portion 48B pushes the position first relay arm 33. As a result, the position operating shaft 24 rotates to rotate the position operating arm 31 backward.

When the position actuating arm 31 rotates rearward, the right end side (the other end side) of the position spool actuating lever 22 moves rearward, whereby the position spool actuating lever 22 moves backward with the left end side (one end side) as a fulcrum. Swing to the side and push the spool 12 from the neutral position.
Then, the control valve 11 is switched to extend the elevating cylinder 9, and the lift arm 8 is rotated upward to raise the work.

When the lift arm 8 is rotated upward, the position feedback rod 77 is pulled by the lift arm 8, whereby the position connecting arm 76 is rotated rearward and the position feedback arm 74 is moved forward via the position feedback shaft 66. Rotate.
When the position feedback arm 74 rotates forward, the left end side of the position spool operating lever 22 moves forward, whereby the position spool operating lever 22 swings forward with the right end side as a fulcrum, and the spool 12 is neutralized. Return to position.

Then, the control valve 11 is switched so as to stop the elevating cylinder 9, the lift arm 8 is stopped, and the work machine is stopped.
On the other hand, when the position operation lever 53 is swung downward (or in a direction in which the work implement such as the front is lowered), the position second relay arm 48 is rotated forward via the position relay lever 51 and the position relay shaft 34. .

  At this time, the spool 12 is pushed from the neutral position by the biasing force F of the spring S that biases the spool 12 in the pushing direction, and the position spool operating lever 22 swings forward with the left end side as a fulcrum. The position operating arm 31 and the position until the position first relay arm 33 comes into contact with the pushing portion 48B of the position second relay arm 48 by swinging forward with the left end side of the spool operating lever 22 as a fulcrum. The first relay arm 33 pivots forward (therefore, when the position operating lever 53 is operated so as to lower the work implement, the spool 12 is moved in the direction of switching the control valve 11 so as to lower the work implement. The position first relay arm 33 follows the pushing portion 48B by the biasing means for biasing).

Further, when the spool 12 is pushed out, the control valve 11 is switched so as to contract the elevating cylinder 9, and the lift arm 8 is rotated downward to lower the operation.
When the lift arm 8 rotates downward, the position feedback rod 77 is pushed by the lift arm 8, whereby the position connecting arm 76 rotates forward and rotates the position feedback arm 74 backward via the position feedback shaft 66. Move.

When the position feedback arm 74 is rotated rearward, the left end side of the position spool operating lever 22 moves rearward. As a result, the position spool operating lever 22 swings rearward with the right end side as a fulcrum, thereby neutralizing the spool 12. Return to position.
Then, the control valve 11 is switched so as to stop the elevating cylinder 9, the lift arm 8 is stopped, and the work machine is stopped.

As described above, in the position control, the work implement moves up and down in proportion to the swing operation amount of the position operation lever 53 (the swing amount with the left end side of the position spool operating lever 22 as a fulcrum). It is configured so that it can be held at a suitable height.
When position control is performed, the lift restricting link 93 is pushed and pulled as the lift arm 8 swings up and down. At this time, the connecting pin 79 only moves relatively in the longitudinal direction in the engagement hole 97. There is no hindrance to position control.

Next, a case where position control and draft control (traction force / position mixing control, mix control) are performed will be described.
In the above-described configuration, the traction load for raising the work implement is set by swinging the draft spool operating lever 23 with the left end side (one end side) as a fulcrum to position the draft joint block 20. This is done by adjusting (adjusting the distance between the draft joint block 20 and the support member 14).

  That is, when the draft operation lever 54 is swung up and down (or back and forth), the draft first relay arm 28 pivots back and forth via the draft relay lever 52, the draft relay shaft 35, and the draft second relay arm 46. When the draft first relay arm 28 rotates back and forth, the draft operating arm 27 rotates back and forth, and the draft spool operating lever 23 swings back and forth with the left end side as a fulcrum. As a result, the position of the draft joint block 20 (the distance between the draft joint block 20 and the support member 14) is adjusted.

  In the present embodiment, when the draft operation lever 54 is swung downward, the draft joint block 20 moves away from the support member 14, and the gap between the draft joint block 20 and the support member 14 is increased. When the draft operation lever 54 is swung upward, the draft joint block 20 moves in a direction approaching the support member 14, and the interval between the draft joint block 20 and the support member 14 is narrow. It is comprised so that it may become.

Further, when the draft operation lever 54 is set to the highest position, the support member 14 is pushed by the draft joint block 20 and the spool 12 is pushed in, so that the working machine can be forcibly raised (drafted up).
When plow work is performed with the work equipment set to the desired height position by the position control described above, if a traction load acts on the work equipment, a compression force acts on the top link, and the top link is attached by the top link. When the bracket 3 is pressed and the torsion bar 5 is twisted, as shown in FIG. 7, the top link mounting bracket 3 swings forward around the torsion bar 5 and pushes the draft feedback rod 71 forward. . At this time, the connecting pin 79 moves forward in the engagement hole 97 to allow the draft feedback rod 71 to move forward.

When the draft feedback rod 71 is pushed forward, the draft connecting arm 70 turns forward and the draft feedback arm 69 turns rearward. The draft feedback arm 69 causes the draft spool operating lever 23 to rotate. The left end moves backward.
When the draft spool operating lever 23 moves backward, the draft spool operating lever 23 swings backward with the right end side (the other end side) as a fulcrum, and the draft joint block 20 is moved rearward along the support shaft 17. .

When an excessive traction load (greater than the set load) acts on the work implement, the draft joint block 20 contacts the support member 14 and pushes it backward.
Then, the spool 12 is pushed from the neutral position, the work implement is raised, and the traction load acting on the work implement is reduced.
When the excessive traction load acting on the work machine is released, the top link mounting bracket 3 is moved in the direction to be restored by the restoring force of the torsion bar 5, and the draft connecting arm 70, the draft feedback shaft 67, the draft feedback arm. 69, the draft spool actuating lever 23 and the draft joint block 20 are moved in a direction to return to the original positions. At this time, since the position spool operating lever 22 is moved by the position feedback mechanism so that the spool 12 is pushed out, the position operation lever 53 is set by the position control operation described above. The work implement descends to the position.

Therefore, in the mix control, traction work such as plow plowing is performed at the position set by the position operation lever 53 below the set traction load, and the draft control is activated when a load greater than the set traction load acts on the work implement. The work equipment is automatically raised to reduce the load.
The lower part of the support member 14 is in contact with a draft joint block 20 (pushing member) to operate the spool 12 so that the working machine is raised when the draft spool operating lever 23 swings with the right end side as a fulcrum. The contact portion 14a is a contact.

  In the above operation, when the excessive pulling load acts on the work machine and the draft spool operating lever 23 swings backward with the right end side as a fulcrum, the position spool operating lever 22 is pushed by the spool 12 being pushed. The position actuating arm 31 and the position first relay arm 33 are rotated rearward with the left end side as a fulcrum, whereby the position actuating portion 48B of the position second relay arm 48 is moved to the position. Since the first relay arm 33 can be contacted only from the front side, the position relay first arm rotates in a direction away from the pushing portion 48B, and the position relay shaft 34, the position relay lever 51, and the position operation lever. 53 is never moved.

  Further, when drafting is performed (when the drafting lever 54 is in the highest position and the support member 14 is pushed by the drafting joint block 20 to push the spool 12 to forcibly raise the working machine) As the lift restricting link 93 is pulled rearward in conjunction with the lifting of the lift arm 8, the connecting pin 79 reaches the front end of the engagement hole 97 when the lift arm 8 approaches the highest lift position.

Further, when the lift arm 8 rises, as shown in FIG. 8, the connection pin 79 is pulled backward by the rise restriction link 93 in the vicinity of the highest rise of the lift arm 8.
When the connecting pin 79 is pulled rearward, the main body rod 81 of the draft feedback rod 71 moves rearward and compresses the spring member 85, thereby reducing the length of the draft feedback rod 71. As a result, the draft connecting arm 70 is rotated rearward, and the draft feedback arm 69 is rotated forward.

When the draft feedback arm 69 rotates forward, the draft spool operating lever 23 swings forward with the right end side as a fulcrum, and the draft joint block 20 moves forward. As a result, the spool 12 is pushed out by the urging force F of the spring S to the neutral position, and the lifting operation of the lift arm 8 is stopped.
As described above, even if the lift arm 8 is forcibly raised by the draft operation lever 54, the lift arm 8 automatically stops near the highest position (the work equipment raising command from the draft operation lever 54 is canceled). Therefore, the draft up function can be used effectively.

When the draft operation lever 54 is returned to the original position, the draft spool operating lever 23 swings forward with the left end side as a fulcrum, the draft joint block 20 moves forward from the support member 14, and the spool 12 Pushed from the neutral position, the lift arm 8 is lowered, and the work implement is lowered to a position set by the position operation lever 53 by the work implement.
In the above configuration, the draft can be raised (the draft operation lever 54 can be operated beyond the most sensitive position of the draft sensitivity), so that the draft joint block 20 is attached to the support member 14 as much as possible. The draft sensitivity can be made close to it.

Further, since the ascending restriction link 93 is added externally and the draft feedback rod 71 is simply replaced with the telescopic draft feedback rod 71, it is possible to easily add functions to the existing machine.
Further, since the ascending restriction link 93 is arranged from the lift arm 8 to the draft connecting arm 70, the interior cylinder type hydraulic elevating device provided with an elevating cylinder for raising and lowering the lift arm 8 in the casing 2, or the present embodiment Either an external cylinder type hydraulic lifting device in which the lifting cylinder 9 is provided outside the casing 2 as in the embodiment can be used.

In the work machine control device having the above-described configuration, when only position control is performed, the draft operation lever 54 is set to the lowest position. At this time, the control valve 11 is not switched and the work implement does not rise even if it swings until an excessive traction load acts on the work implement and the top link mounting bracket 3 contacts the casing 2.
When only the draft control is performed, the position operation lever 53 is operated to the lowest position so that the work implement is in a state of being lowered (floating state).

  As a result, in the draft control, when a traction load greater than the traction load set on the work implement is applied, the work implement can be automatically raised to perform work with a constant traction load.

DESCRIPTION OF SYMBOLS 1 Car body 2 Casing 5 Load sensing member 8 Lift arm 9 Lifting cylinder 11 Control valve 12 Spool 14a Contacting part 20 Pushing member 23 Draft spool operating lever 54 Draft operating means 67 Draft feedback shaft 69 Draft feedback arm 70 Draft connecting arm 71 Draft feedback rod 79 Connecting pin 81 Body rod 82 Cylindrical member 83 Spring receiving member 84 Spring receiving member 85 Spring member 93 Ascent restriction link 95 Engagement plate 97 Engagement hole

Claims (3)

A casing (2) provided on the rear part of the vehicle body (1) is provided with a lift arm (8) for raising and lowering a working machine attached to the vehicle body (1) so as to be able to swing up and down, and the lift arm (8) is provided. An elevating cylinder (9) that swings up and down is provided. Inside the casing (2), a control valve (11) that switches the flow of pressure oil to the elevating cylinder (9), and a spool (12) of the control valve (11) A draft spool actuating lever (23) for operating the draft spool actuating lever (23) is swingable with one end side as a fulcrum by a draft operating means (54), and the casing (2) A draft having one end side interlocked with a load sensing member (5) side for detecting a load acting on the work implement and the other end side interlocked with one end side of a draft spool operating lever (23). A feedback rod (71) is provided, and when a traction load higher than the setting acts on the work implement, the draft feedback rod (71) is pushed from the load sensing member (5) side to one end side of the draft spool operating lever (23). By being moved, the draft spool operating lever (23) swings with the other end as a fulcrum, and the pushing member (20) provided on the draft spool operating lever (23) is provided on the spool (12) side. The spool (12) is operated to raise the work implement by pushing the contact portion (14a), and the draft spool operating lever (23) is swung around one end side as a fulcrum. A tractor work implement control device capable of setting a traction load to raise the work implement by adjusting the position of the pushing member (20) with respect to the portion (14a). In,
An ascending restriction link (93) having one end side linked to the lift arm (8) and the other end linked to the other end side of the draft feedback rod (71) is provided, and the draft operating means (54) The contact member (14a) can be forcibly pushed by the moving member (20) so that the work implement can be raised, and the contact member (14a) can be moved by the pushing member (20). When the draft operating means (54) is operated so as to forcibly push it, if the lift arm (8) swings upward near the highest position, the lift arm (8) is lifted to stop the lifting operation. With the ascending restriction link (93), the draft spool operating lever (23) is swung in the direction away from the contact portion (14a) with the other end as a fulcrum, and this is allowed. Work machine control device of the tractor, characterized by being configured to urchin length of the draft feedback rod (71) is contracted.   A draft feedback shaft (67) that passes through the casing (2) and is supported by the casing (2) so as to be rotatable about its axis is provided on the inner end side of the draft feedback shaft (67). A draft feedback arm (69) connected to one end of the spool operating lever (23) is provided, and the other end of the draft feedback rod (71) is connected to the connecting pin (79) on the outer end of the draft feedback shaft (67). An engagement plate (95) having an engagement hole (97) through which the connection pin (79) is inserted on the other end side of the ascending restriction link (93). The engaging hole (97) is formed in a long hole shape, and the connecting pin (79) passes through the engaging hole (97) until the lift arm (8) reaches near the highest position. When the lift arm (8) reaches the vicinity of the highest position, the connecting pin is pulled at the end of the engagement hole (97), so that the draft feedback shaft (67) is passed through the draft connecting arm (70). The draft feedback shaft (67) is rotated so that the draft spool operating lever (23) is brought into contact with the other end side as a fulcrum through the draft feedback arm (69). 2. The tractor work implement control device according to claim 1, wherein the tractor work implement control device is configured to swing in a direction away from the portion (14a). The draft feedback rod (71) includes a main body rod (81) constituting one end in the length direction, a cylindrical member (82) constituting the other end in the length direction, and the other end in the length direction of the main body rod (81). A spring receiving member (83) fixed to the side and inserted into the cylindrical member (82), and a spring receiving member (84) fixedly provided at the other longitudinal end in the cylindrical member (82) And a spring member (85) interposed in a compressed manner between the spring receiving members (83, 84). The spring member (85) is contracted to shorten the length. The tractor work machine control device according to claim 1, wherein the tractor work machine control device is provided.

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