JP2006333741A - Implement controller of tractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify an implement controller for controlling the position and/or draft of an implement liftably mounted on the rear portion of a tractor. <P>SOLUTION: This implement controller equipped with a draft operation lever 23 for feeding back the lifting quantity of the implement and swinging a position spool operation lever 22 on the other side as a support to return a spool 12 of a control valve 11 to a neutral position, and for swinging on one end as a support to operate the spool 12 to lift the implement is characterized by swinging the operation lever 23 on the other side as a support to set a pulling load to lift the implement, cylindrically forming an operation shaft 25 among a position operation shaft 24 which is turned on the axis to swing an operation lever 22 on the other side as a support, and the draft operation shaft 25 which is turned on the axis to swing the operation lever 23 on the other side as a support, and concentrically inserting the other operation shaft 24 into the cylinder. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

Conventionally, as a tractor work machine control device, a single control valve is used to perform position control and / or draft control of a work machine mounted on the rear part of a tractor so as to be movable up and down. No. 1-148107 and JP-A-1-148109.
The tractor work implement control device includes a hydraulic lift device that lifts and lowers a work implement mounted on a vehicle body, and a hydraulic oil for the hydraulic lift device that lifts the work implement by operating a spool from a neutral position. A control valve for switching the flow, a spool operating lever for position that operates the spool of the control valve by swinging with one end side as a fulcrum, and a swing amount with one end side of the spool operating lever for position as a fulcrum A position feedback mechanism for returning the spool to the neutral position by feeding back the lifting amount of the working machine and swinging the position spool operating lever with the other end as a fulcrum in order to raise and lower the working machine, and the desired lifting position of the working machine The position spool lever can be rotated by rotating the position operation lever. A position operating shaft that swings the lever with one end as a fulcrum, and a draft that raises the work implement by operating the spool by swinging with one end as a fulcrum when a traction load greater than the setting acts on the work implement The spool operating lever, the draft operating shaft that rotates around the shaft center by the operation of the draft operating lever and sets the traction load that should raise the work implement, and the position operating shaft and the position spool operating lever are linked to each other And a draft link mechanism for interlockingly connecting the draft operating shaft and the draft spool operating lever.
JP-A-1-148107 JP-A-1-148109

In the conventional work machine control device for a tractor, a position link mechanism for interlockingly connecting the position operating shaft and the position spool operating lever, and a draft for interlockingly connecting the draft operating shaft and the draft spool operating lever. There is a problem that the structure of the link mechanism is complicated, and the number of parts and assembly man-hours are large.
In view of the above problems, an object of the present invention is to provide a work machine control device for a tractor with a simplified structure.

  The technical means taken by the present invention in order to solve the technical problem is to lift and lower the work implement by operating the spool from the neutral position and a hydraulic lift device that raises and lowers the work implement mounted on the vehicle body. A control valve for switching the flow of pressure oil to the hydraulic lifting device, a position spool operating lever for operating the spool of the control valve by swinging with one end side as a fulcrum, and one end side of the position spool operating lever Position feedback for returning the spool to the neutral position by feeding back the lifting / lowering amount of the work implement in order to raise / lower the work implement in proportion to the swing amount with the other end side as the fulcrum, The position spool operating lever is swung about one end side as a fulcrum by rotating around the mechanism and the axis. A tractor equipped with a transition operating shaft and a draft spool operating lever that lifts the working machine by operating the spool by swinging with one end side as a fulcrum when a traction load greater than the setting acts on the working machine In the work implement control device, the draft spool operating lever can be set with the other end side as a fulcrum to enable setting of the traction load to raise the work implement, and by rotating the draft spool around the axis And a draft operating shaft for swinging the spool operating lever with the other end side as a fulcrum. One operating shaft of the draft operating shaft or the position operating shaft is formed of a cylinder, and the other operating shaft is disposed in the cylinder. It is characterized by being inserted concentrically.

  Further, another technical means includes a hydraulic lifting device that lifts and lowers the working machine mounted on the vehicle body, and pressure oil for the hydraulic lifting device so as to lift and lower the working machine by operating the spool from the neutral position. A control valve for switching the flow, a spool operating lever for position that operates the spool of the control valve by swinging with one end side as a fulcrum, and a swing amount with one end side of the spool operating lever for position as a fulcrum A position feedback mechanism that returns the spool to the neutral position by feeding back the lifting amount of the working machine and swinging the position spool operating lever with the other end as a fulcrum in order to raise and lower the working machine, and pulling more than set to the working machine When the load is applied, the work implement is lifted by operating the spool by swinging around one end side as a fulcrum. In a tractor work machine control device having a ft spool operating lever, when the draft spool operating lever swings around one end side as a fulcrum, it comes into contact with a contact portion provided on the spool side. The pushing member for operating the spool so that the working machine is raised by pushing this portion is connected to the draft spool operating lever, and the draft spool operating lever is swung around the other end as a fulcrum. By adjusting the position of the pushing member, it is possible to set the traction load for raising the work implement.

  The position operating shaft is provided with a position first relay arm, and a position relay shaft that is rotated around the axis by operation of a position operating means for operating the work machine to a desired lift position is provided. Two relay arms are provided, and when the position operating means is operated to raise the work implement to this position second relay arm, the position is operated by contacting and pushing the position first relay arm A pusher that switches the control valve to raise the work implement by rotating the shaft is provided, and the position spool operating lever operates to raise the work implement, and the position is determined by the operation from the position spool operating lever. When the operating shaft is rotated, the position relay first arm is configured to be separated from the pushing portion. In addition, when the position operating means is operated to lower the work implement, the position first relay arm is moved by the biasing force of the biasing means that biases the spool in the direction of switching the control valve so as to lower the work implement. It is good to comprise so that it may follow a pushing part.

  Also, a draft first relay arm is provided on the draft operating shaft, and a draft relay shaft that rotates around the axis by the operation of the draft operating means for setting the traction load to raise the work implement is provided. A draft second relay arm that engages with the first draft relay arm is provided so that the draft operation shaft is rotated by rotation of the draft relay shaft, the position relay shaft and the draft relay shaft are mounted, and the vehicle body The position second relay arm is engaged with the position first relay arm by attaching the mounting frame to the vehicle body with the position relay shaft and the draft relay shaft assembled to the mounting frame. And the draft second relay arm is configured to engage the draft first relay arm. It can have.

  ADVANTAGE OF THE INVENTION According to this invention, the simplification of the working machine control apparatus which performs position control and / or draft control of the working machine with which the rear part of the tractor was attached so that raising / lowering was possible can be achieved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 2, reference numeral 1 denotes a transmission case that forms the rear part of the tractor body. The transmission case 1 is attached to the upper surface of the transmission case 1 so as to cover an opening formed on the upper surface of the transmission case 1. A mounting body 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.

A bracket mounting portion 4 for mounting the top link mounting bracket 3 is provided at the rear portion of the mounting body 2, and the bracket mounting portion 4 has a torsion bar (load detection means) 5 having an axis in the left-right direction. A top link mounting bracket 3 is mounted, and one end side (tractor side) of the top link of the three-point link mechanism is selectively pivotally connected to one of the mounting holes 6 provided in the top link mounting bracket 3.
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 of the tractor so as to be movable up and down via a three-point link mechanism.

Lift arm pivots 7 are provided in the front-rear halfway portions of the left and right side surfaces of the mounting body 2, and the bases of the lift arms 8 are rotatable about the left and right axial centers on the left and right lift arm pivots 7. One end side of the lift rod is pivotally connected to the distal end side 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 a middle portion in the longitudinal direction of the lower link.
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.

By extending and retracting the left and right lifting cylinder 9 (projecting and retracting the piston rod), the left and right lift arms 8 swing up and down around the rotation axis, and 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 so that the work implement moves up and down.
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 rotates 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 mounting body 2, the lift arm 8, the lift rod, the lift cylinder 9 and the like mainly constitute a hydraulic lift 10 that lifts and lowers the work implement.
A control valve 11 for controlling the elevating cylinder 9 is disposed in the front portion on the inner side (lower surface side) of the mounting body 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. From the neutral position where supply / discharge of pressure oil to the lifting cylinder 9 is stopped, the rising position for supplying pressure oil to the piston top side of the cylinder body of the lifting cylinder 9, and the piston top side of the cylinder body of the lifting cylinder 9 The spool 12 is switched to the lowered position for discharging the pressure oil, and the control valve 11 is switched. The spool 12 lowers the work implement (contracts the lifting cylinder 9 or lift arm 8). It is urged by a spring in a direction to switch the control valve 11 so as to rotate 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 that the spool 12 is lowered (the spool 12 is switched to the lowered position), and the spool 12 is biased in the direction of being pulled out by the biasing force F of the spring.
As shown in FIGS. 1, 3, 6, and 7, a mounting block 13 is fixedly attached to the front end side (front end side) of the spool 12 of the control valve 11. A mounting member 14 composed of, for example, is fixed. The mounting member 14 protrudes downward from the tip of the spool 12, and a pair of upper and lower support shafts 16, 17 having a front-rear axial center on the front side of the mounting member 14. Is provided.

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). 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 in a position directly below the upper support shaft 16 in parallel with the upper support shaft 16. The lower support shaft 17 has a draft joint block (pushing member) 20. Is pivotally fitted around the shaft center so as to be movable in the axial direction (front-rear direction). A draft joint pin 21 having a vertical shaft center is provided on the lower surface side of the draft joint block 20. Is fixed.

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.
Both the position operating shaft 24 and the draft operating shaft 25 have left and right axial centers. In the present embodiment, the draft operating shaft 25 is formed of a cylindrical body, and the right wall portion of the mounting body 2 is left and right. It is inserted into a support hole 26 formed so as to penetrate in the direction, and is supported by the support hole 26 so as to be rotatable about an axis, and the position operating shaft 24 is inserted into a draft operating shaft 25 and is supported by the draft. The position operating shaft 24 and the draft operating shaft 25 are arranged concentrically.

The position operating shaft 24 may be a cylinder, and the draft operating shaft 25 may be inserted through the cylinder.
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. 3 and 4, 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, and the position relay shaft 34 and the draft relay shaft 35 are detachably attached to the right side of the mounting body 2 by bolts. And is supported so as to be rotatable around an axis.

As shown in FIGS. 4, 8, and 9, the mounting frame 36 includes a main frame 37 and a pair of upper and lower support cylinders 38. The side walls 37a and 37b and a rear wall 37c connecting the rear edge sides of the inner side wall 37a and the outer side wall 37b are formed in a U shape in plan view.
The main frame 37 is bolted to the mounting body 2 by a mounting portion 39 at the front lower portion of the inner wall 37a, a mounting plate 40 fixed to the inner wall 37a, and a mounting plate 41 fixed to the rear wall 37c. Yes.

The inner and outer walls 37a and 37b of the main frame 37 are connected by upper and lower connecting plates 42.
In addition, an insertion portion 43 for inserting the draft operating shaft 25 is formed in the lower portion of the inner wall of the main frame 37, and the insertion portion 43 is configured by an open U-shaped notch 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.

  As shown in FIG. 5C, the draft second relay arm 46 has an arm body 46A that contacts the front side of the engagement pin 29 of the draft first relay arm 28, and a lower rear side of the arm body 46A. It is composed of a hook-shaped engagement portion 46B that is fixed and contacts the rear side of the engagement pin 29, and is fitted (engaged) from above to the engagement pin 29 from the arm main body 46A and the engagement portion 46B. ) So that the draft second relay arm 46 is interlocked with the draft first relay arm 28 by fitting the fitting portion 46C to the engagement pin 29 from above. It is configured.

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. 5A and 5B, 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, so that the position relay shaft A position relay lever 51 is fixed to the mounting plate 49 fixed to 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 rod or the like, and a draft operation as a draft operation means operated by the operator is connected to the draft relay lever 52. The lever 54 is interlocked and connected through a rod or the like.

The position operation lever 53 and the draft operation lever 54 are supported by a common 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 59 penetrates through the pressure plate 62, the spring receiving plate 56, and the stopper plate 44, and the inner ends of the bolts 59 in the left-right direction are screwed into fixing nuts 60 fixed to the stopper plate 44. A tightening nut 61 is screwed onto the outer end of each bolt 59 in the left-right direction. By tightening the tightening nut 61, a predetermined operation resistance is applied to the draft relay shaft 35 or the position relay shaft 34. It is configured.

  In the relay mechanism that relays between the position operation lever 53 and the draft operation lever 54 and the position operation shaft 24 and the draft operation shaft 25 having the above-described configuration, the insertion portion 43 below the inner wall 37a of the main frame 37 has a draft. The operating shaft 25 can be externally fitted from above, the position first relay arm 33 and the position second relay arm 48 can be freely engaged and disengaged, and the draft first relay arm 28 and the draft second relay arm 46 Since the position relay shaft 34, the draft relay shaft 35, the mounting plates 49, 50, etc. are assembled to the mounting frame 36, the mounting frame 36 is mounted to the mounting body 2 (tractor vehicle body side). As a result, the position second relay arm 48 engages with the position first relay arm 33 and the draft second relay. Over arm 46 is configured to engage the first relay arm 28 draft.

The draft operating shaft 25 is prevented from being removed from the support hole 26 by a washer 63 attached to the draft operating shaft 25 coming into contact with the inner wall 37a of the main frame 37. The washer 64 attached to the position operating shaft 24 comes into contact with the end of the draft operating shaft 25 so that it is prevented from being removed from the draft operating shaft 25.
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 have a lateral axis, and the draft feedback shaft 67 is formed of a cylindrical body in the present embodiment, and the left wall portion of the mounting body 2 The position feedback shaft 66 is inserted into a draft feedback shaft 67 and is inserted into a support hole 68 formed so as to penetrate in the left-right direction. The position feedback shaft 66 and the draft feedback shaft 67 are arranged concentrically.

The position feedback shaft 66 may be a cylinder, and the draft feedback shaft 67 may be inserted through the cylinder.
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 and 11, one end side (front end side) of the draft feedback rod 71 is pivotally connected to the front end side of the draft connection arm 70, and the other end side (rear end) of the draft feedback rod 71. The side) is pivotally connected to a mounting bracket 72 fixed to the top link mounting bracket 3 so that its position in the length direction can be adjusted.

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 73.
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.

Further, the left and right outer ends of the position feedback shaft 66 protrude in the left and right directions from the draft feedback shaft 67, 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 protruding manner on the lower side in the direction.
As shown in FIGS. 2 and 10, one end side (front end side) of the position feedback rod 77 is pivotally connected to the front end side of the position connecting arm 76, and the other end side (rear end) of the position feedback rod 77 is connected. Side) is pivotally coupled to a pivot coupling portion 78 on the base side of the lift arm 8 so that the position in the length direction can be adjusted.

A position feedback mechanism 79 is constituted by the position feedback shaft 66, the position feedback arm 74, the position connecting arm 76, the position feedback rod 77, and the like.
The draft feedback shaft 67 is fitted to the draft feedback shaft 67 so as to be rotatable relative to the draft feedback shaft 67, and is secured by a retaining plate 81 that is bolted to the outer surface of the mounting body 2. The position feedback shaft 66 is secured to the position feedback shaft 67. The washer 82 attached to 66 is brought into contact with the end of the draft feedback shaft 67 to prevent the draft feedback shaft 67 from coming off.

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 the work implement mounted on the tractor is stopped between the ascending limit and the descending limit, that is, when the spool 12 is in the neutral position, the position operating lever 53 is moved upward (or rearward, in the direction of raising the implement). ), The position second relay arm 48 rotates 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. Then, the position operating shaft 24 rotates to rotate the position operating arm 31 to the rear side.

When the position operating arm 31 is rotated rearward, the right end side of the position spool operating lever 22 is moved backward, and thereby the position spool operating lever 22 is swung backward with one end side (left end side) as a fulcrum. 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, so that the position spool operating lever 22 swings forward using the other end side (right end side) as a fulcrum. Return the spool 12 to the neutral 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 forward, in the direction of lowering the work implement), the position second relay arm 48 rotates 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 that biases the spool 12 in the pushing direction, and the position spool operating lever 22 swings forward with one end side as a fulcrum. 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 one end side of the spool operating lever 22 as a fulcrum, the position operating arm 31 and the position first 1 The relay arm 33 pivots forward (therefore, when the position operation lever 53 is operated so as to lower the work implement, the spool 12 is attached in a direction to switch 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.

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 is moved rearward. As a result, the position spool operating lever 22 swings rearward with the other end side as a fulcrum, and the spool 12 is moved. Return to the neutral 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 one end side of the position spool operating lever 22 as a fulcrum) so that the work implement can be operated. It is configured so that it can be held at a suitable height.
Next, a case where position control and draft control (traction force / position mixing control, mix control) are performed will be described.

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, the top link mounting bracket 3 swings forward around the torsion bar 5 to move the draft feedback rod 71 forward as indicated by a virtual line in FIG. Push.
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 one end side (right 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 mounting 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 operating lever 23 and the draft joint block 20 move in a direction to return to their original positions. At this time, the position feedback operating mechanism 79 moves the position spool operating lever 22 to the state where the spool 12 is pulled out. In this state, the work implement is lowered to the position set by the position operation lever 53.

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.
In the above operation, when the excessive pulling load acts on the work machine and the draft spool operating lever 23 swings backward with one end side as a fulcrum, the position spool operating lever 22 causes the spool 12 to be pushed in. The position actuating arm 31 and the position first relay arm 33 are rotated rearward with the one end side as a fulcrum, and the push 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 not moved, and the operational reliability is improved.

Also, the lower part of the mounting member 14 is provided with a pushing member (draft joint block 20) for operating the spool 12 so that the working machine rises when the draft spool operating lever 23 swings around one end side. It is set as the contact part 14a which contacts.
The traction load for raising the work implement is adjusted by adjusting the position of the draft joint block 20 by swinging the draft spool operating lever 23 around the other end (the contact with the draft joint block 20). The distance L between the unit 14a and the unit 14a is adjusted).

That is, by swinging the draft operation lever 54 up and down (or back and forth), the draft first relay arm 28 rotates back and forth via the draft relay lever 52, the draft relay shaft 35, and the draft second relay arm 46. At the same time, the draft actuating arm 27 pivots back and forth, and the draft spool actuating lever 23 swings back and forth with the other end as a fulcrum, so that the draft joint block 20 position (contact with the draft joint block 20) is reached. The distance L) from the part 14a is adjusted.
When the draft operation lever 54 is swung downward, the draft joint block 20 moves away from the contact portion 14a, and the interval L between the draft joint block 20 and the contact portion 14a is increased. Further, when the draft operation lever 54 is swung upward, the draft joint block 20 moves in a direction approaching the contact portion 14a, and the draft joint block 20 and the contact portion 14a are moved. The interval L becomes smaller.

Further, when the draft operation lever 54 is set to the highest position, the working portion can be forcibly raised (drafted up) by pushing the contact portion 14a by the draft joint block 20 and pushing in the spool 12. It is configured as follows.
In the work machine control device having the above configuration, the configuration is greatly simplified as compared with the conventional link mechanism, the number of parts and the number of assembly steps can be reduced, and the operation reliability can be improved. it can.
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, even if the excessive traction load acts on the work implement and swings until the top link mounting bracket 3 contacts the attachment body 2, the control valve 11 is not switched and the work implement does not rise.

  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.

It is a front fragmentary sectional view of the principal part of a working machine control apparatus. It is a side view of the rear upper part of a tractor vehicle body. It is a front fragmentary sectional view of a working machine control apparatus. It is front sectional drawing of the relay mechanism which relays a position operation lever and a draft operation lever, a position action shaft, and a draft action shaft. (A) is the AA arrow line cross section of FIG. 4, (b) is the BB line arrow cross section of FIG. 4, (c) is CC line arrow cross section of FIG. It is side surface sectional drawing which shows the structure of the connection part of the spool of a control valve, the spool operating lever for positions, and the spool operating lever for drafts. It is a top view which shows the structure of the connection part of the spool of a control valve, the spool operating lever for positions, and the spool operating lever for drafts. It is a side view of the relay mechanism which relays a position operation lever and a draft operation lever, a position spool operation lever, and a draft spool operation lever. It is a top view of the attachment frame which supports a relay mechanism. It is a side view of a position feedback mechanism. It is a side view of a draft feedback mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hydraulic lift 11 Control valve 12 Spool 14a Contact part 20 Pushing member 22 Position spool operating lever 23 Draft spool operating lever 24 Position operating shaft 25 Draft operating shaft 28 Draft first relay arm 33 Position first relay arm 34 Position relay shaft 35 Draft relay shaft 36 Mounting frame 46 Draft second relay arm 48 Position second relay arm 48B Pushing portion 53 Position operation lever (position operation means)
54 Draft operation lever (draft operation means)
79 Position feedback mechanism F

Claims (4)

A hydraulic lifting device (10) that lifts and lowers the working machine mounted on the vehicle body, and pressure oil for the hydraulic lifting device (10) to lift and lower the working machine by operating the spool (12) from the neutral position. A control valve (11) for switching the flow, a position spool operating lever (22) for operating the spool (12) of the control valve (11) by swinging with one end side as a fulcrum, and the position spool operating lever ( 22) by feeding back the lifting / lowering amount of the working machine in proportion to the swinging amount with one end side as a fulcrum and swinging the position spool operating lever (22) with the other end side as a fulcrum. A position feedback mechanism (79) for returning the spool (12) to the neutral position, and a spool operating lever for the position by rotating around the shaft center 22) The position operating shaft (24) that swings with one end side as a fulcrum, and the spool (12) is operated by swinging with one end side as a fulcrum when a traction load greater than the setting acts on the work implement. In the tractor work machine control device comprising the draft spool operating lever (23) for raising the work machine by
The draft spool operating lever (23) is swung with the other end as a fulcrum, so that the traction load for raising the work implement can be set, and the draft spool is operated by rotating around the axis. A draft operating shaft (25) for swinging the lever (23) with the other end as a fulcrum is provided, and one of the operating shaft (25) of the draft operating shaft (25) or the position operating shaft (24) is a cylinder. A working machine control device for a tractor, characterized in that the other operating shaft (24) is inserted concentrically into the cylinder. A hydraulic lifting device (10) that lifts and lowers the working machine mounted on the vehicle body, and pressure oil for the hydraulic lifting device (10) to lift and lower the working machine by operating the spool (12) from the neutral position. A control valve (11) for switching the flow, a position spool operating lever (22) for operating the spool (12) of the control valve (11) by swinging with one end side as a fulcrum, and the position spool operating lever ( 22) by feeding back the lifting / lowering amount of the working machine in proportion to the swinging amount with one end side as a fulcrum and swinging the position spool operating lever (22) with the other end side as a fulcrum. A position feedback mechanism (79) for returning the spool (12) to the neutral position, and one end side as a fulcrum when a traction load exceeding the setting is applied to the work implement In the working machine controller of a tractor equipped with a draft spool actuating lever to raise the working machine (23) by actuating the spool (12) by moving,
When the draft spool operating lever (23) swings around one end side as a fulcrum, the draft spool operating lever (23) contacts the contact portion (14a) provided on the spool (12) side and pushes the contact portion (14a). The pusher member (20) for operating the spool (12) is connected to the draft spool actuating lever (23) so that the work implement is lifted, and the other end side of the draft spool actuating lever (23) is supported as a fulcrum. The tractor work implement control apparatus according to claim 1, wherein the traction load for raising the work implement can be set by adjusting the position of the push member (20) by swinging as follows.   A position relay shaft (34) which is provided with a position first relay arm (33) on the position operating shaft (24) and rotates about the axis by operation of a position operation means (53) for operating the working machine to a desired lift position. When a position second relay arm (48) is provided on the position relay shaft (34), and the position operating means (53) is operated on the position second relay arm (48) to raise the work implement. Further, when the position first connecting arm (33) is contacted and pushed, the position operating shaft (24) is rotated to switch the control valve (11) so as to raise the work implement. The position spool operating lever (22) is operated so as to raise the work implement and the position spool operating lever (22) is operated. Therefore, when the position operating shaft (24) rotates, the position relay first arm (33) is configured to be separated from the pushing portion (48B), and the position operation is performed to lower the work implement. When the means (53) is operated, the position first relay arm is moved by the biasing force (F) of the biasing means for biasing the spool (12) in the direction of switching the control valve (11) so as to lower the work implement. The tractor work machine control device according to claim 1, wherein (33) is configured to follow the pushing portion (48B).   The draft relay shaft (25) is provided with a draft first relay arm (28), and is rotated around the axis by the operation of the draft operating means (54) for setting the traction load to raise the work implement. 35) is provided, and the draft relay shaft (35) is engaged with the draft first relay arm (28) so that the draft operating shaft (25) is rotated by the rotation of the draft relay shaft (35). A draft second relay arm (46) is provided, and a mounting frame (36) to which the position relay shaft (34) and the draft relay shaft (35) are attached and attached to the vehicle body side is provided. By attaching the mounting frame (36) to the vehicle body side with the position relay shaft (34) and the draft relay shaft (35) assembled, the position The second relay arm (48) is configured to engage with the position first relay arm (33) and the draft second relay arm (46) is engaged with the draft first relay arm (28). The tractor work machine control device according to claim 3.

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