JP6544644B2 - Tractor - Google Patents

Description

  The present invention relates to a tractor.

  Conventionally, a tractor which is a typical work vehicle is known (see Patent Document 1). A tractor can tow a tilling machine to plow the field. In addition, the tractor can raise and lower the tilling machine by the operation of the hydraulic actuator.

  By the way, the tractor is provided with a position lever and an automatic lever. The position lever can set the height position of the tilling machine by operating the hydraulic actuator via the link mechanism. The automatic lever can set the tilling depth of the tilling machine by operating the hydraulic actuator via the link mechanism. In addition, there has been proposed a tractor in which a link mechanism on the position lever side cooperates with a link mechanism on the automatic lever side to enable large control of the tillage depth. However, such a tractor may not be able to control the tilling depth appropriately in a predetermined setting state. For example, when the front wheel of the tractor sinks in a predetermined setting state, there is a case where the tilling depth can not be maintained constant without the lowering of the tilling machine.

JP, 2013-183709, A

  To provide a tractor capable of controlling the plow depth appropriately.

  The problem to be solved by the present invention is as described above, and next, means for solving the problem will be described.

  The invention according to claim 1 comprises a position lever, a first shaft interlocking with the position lever, a first cross link interlocking with the first shaft, an auto lever, and a second shaft interlocking with the auto lever A second cross link interlocking with the second shaft; and a control shaft rotatably supporting the first cross link and the second cross link, the hydraulic pressure according to the sliding position of the control shaft A tractor operated by an actuator, comprising: a cam plate rotated by the auto lever; and a cam follower attached to the second shaft in contact with the cam plate, wherein the cam plate is operated when the auto lever is operated. And the second shaft is interlocked with the second cam follower. The control shaft is slid by the cross linking is intended.

  The invention according to claim 2 is the tractor according to claim 1, further comprising an idle arm attached to the first shaft, and when the auto lever is operated in one direction, the idle arm is guided by the cam plate The first shaft interlocks, and the control shaft slides by the first cross link in addition to the second cross link.

  The invention according to claim 3 is the tractor according to claim 2, wherein when the auto lever is operated further to one side, the cam plate is separated from the idle arm, and the control shaft is slid only by the second cross link. It is something that moves.

  The invention according to a fourth aspect is the tractor according to the first aspect, further comprising an idle arm attached to the first shaft, and the cam plate is brought close to the idle arm when the auto lever is operated to the other. The control shaft slides only by the second cross link.

  According to a fifth aspect of the present invention, in the tractor according to the fourth aspect, when the auto lever is further operated to the other side, the idle arm is guided by the cam plate and the first shaft interlocks, the second cross The control shaft is slid by the first cross link in addition to the link.

  The invention according to claim 6 is the tractor according to any one of claims 1 to 5, wherein the cam plate is provided with a first cam area and a second cam area, and the cam follower is provided in the first cam area. When the auto lever is operated, the cam follower is guided by the cam plate and the second shaft interlocks in a small interlock, and when the cam follower contacts the second cam region, the auto lever is operated The cam follower is guided to the cam plate, and the second shaft is largely interlocked, and the control shaft is slid by the first cross link in addition to the second cross link alone or the second cross link. .

The invention according to claim 7 is the tractor according to claim 2 or 4 , wherein an adjuster bolt is provided at a contact of the cam plate and the idle arm, and the control shaft slides only by the second cross link. A switching timing of an aspect and an aspect in which the control shaft slides by the first cross link in addition to the second cross link can be adjusted.

  The effects of the present invention are as follows.

  According to the first aspect of the present invention, the present tractor comprises a cam plate rotated by an automatic lever, and a cam follower attached to the second shaft in contact with the cam plate. Then, when the auto lever is operated, the cam follower is guided by the cam plate, the second shaft interlocks, and the control shaft slides by the second cross link. Thus, in the present tractor, the operation amount of the hydraulic actuator with respect to the operation amount of the auto lever is determined based on the cam profile of the cam plate that constitutes the link mechanism on the auto lever side. That is, in the present tractor, the displacement amount of the tilling depth with respect to the operation amount of the auto lever is determined based on the cam profile of the cam plate that constitutes the link mechanism on the auto lever side. Therefore, this tractor can control the tilling depth appropriately.

  According to the invention set forth in claim 2, the present tractor comprises an idle arm attached to the first shaft. Then, when the auto lever is operated in one direction, the idle arm is guided by the cam plate to interlock the first shaft, and the control shaft slides by the first cross link in addition to the second cross link. Thus, in the present tractor, the link mechanism on the side of the position lever cooperates with the link mechanism on the side of the auto lever in a region where the inclination angle of the auto lever is small, and the operation amount of the hydraulic actuator with respect to the operation amount of the auto lever is determined. That is, in the present tractor, the link mechanism on the position lever side cooperates with the link mechanism on the auto lever side in the region where the inclination angle of the auto lever is small, and the displacement amount of the tillage depth with respect to the operation amount of the auto lever is determined. Therefore, this tractor can control the tilling depth appropriately.

  According to the invention as set forth in claim 3, in the present tractor, when the auto lever is operated further to one side, the cam plate is separated from the idle arm, and the control shaft slides by only the second cross link. Thus, in the present tractor, in the region where the inclination angle of the auto lever is large, the link mechanism on the auto lever side determines the operation amount of the hydraulic actuator with respect to the operation amount of the auto lever. That is, in this tractor, the displacement amount of the tillage depth with respect to the operation amount of the auto lever is determined by the link mechanism on the auto lever side in the region where the tilt angle of the auto lever is large. Therefore, this tractor can control the tilling depth appropriately.

  According to the invention set forth in claim 4, the present tractor comprises an idle arm attached to the first shaft. Then, when the auto lever is operated to the other side, the cam plate approaches the idle arm, and the control shaft slides by only the second cross link. Thus, in the present tractor, in the region where the inclination angle of the auto lever is large, the link mechanism on the auto lever side determines the operation amount of the hydraulic actuator with respect to the operation amount of the auto lever. That is, in this tractor, the displacement amount of the tillage depth with respect to the operation amount of the auto lever is determined by the link mechanism on the auto lever side in the region where the tilt angle of the auto lever is large. Therefore, this tractor can control the tilling depth appropriately.

  According to the invention as set forth in claim 5, when the automatic lever is further operated to the other side, the idle arm is guided by the cam plate and the first shaft interlocks with the second cross link in addition to the second cross link. The link causes the control shaft to slide. Thus, in the present tractor, the link mechanism on the side of the position lever cooperates with the link mechanism on the side of the auto lever in a region where the inclination angle of the auto lever is small, and the operation amount of the hydraulic actuator with respect to the operation amount of the auto lever is determined. That is, in the present tractor, the link mechanism on the position lever side cooperates with the link mechanism on the auto lever side in the region where the inclination angle of the auto lever is small, and the displacement amount of the tillage depth with respect to the operation amount of the auto lever is determined. Therefore, this tractor can control the tilling depth appropriately.

  According to the invention described in claim 6, in the present tractor, the cam plate is provided with the first cam area and the second cam area. When the cam follower is in contact with the first cam area, the cam follower is guided to the cam plate and the second shaft interlocks in a small interlock when the auto lever is operated. When the cam follower is in contact with the second cam area, the auto lever is operated: The cam follower is guided to the cam plate and the second shaft is largely interlocked, and the control shaft is slid by the first cross link in addition to the second cross link or the second cross link. As a result, in this tractor, the operation amount of the hydraulic actuator with respect to the operation amount of the auto lever is small in the region where the inclination angle of the auto lever is small, and the operation amount of the hydraulic actuator with respect to the operation amount of the auto lever in the region where the inclination angle of the auto lever is large. Becomes larger. That is, this tractor has a small displacement amount of the tilling depth with respect to the operation amount of the auto lever in the region where the inclination angle of the auto lever is small, and a displacement of the tillage depth with respect to the operation amount of the auto lever in the region where the inclination angle of the auto lever is large. The amount will increase. Therefore, this tractor can control the tilling depth appropriately.

  According to the seventh aspect of the present invention, the tractor is provided with the adjuster bolt at the contact point of the cam plate and the idle arm. And, the switching timing of the mode in which the control shaft slides only by the second cross link and the mode in which the control shaft slides by the first cross link in addition to the second cross link can be adjusted. Thus, in the present tractor, when the length of the adjuster bolt is shortened, a mode in which the control shaft slides only by the second cross link becomes dominant, and when the length of the adjuster bolt is increased, the second cross link is added The manner in which the control shaft slides by the cross link is dominant. That is, when the length of the adjuster bolt is shortened, the scope of application of the embodiment in which the control shaft slides only by the second cross link is broadened, and when the length of the adjuster bolt is increased, the second cross link is added to the second cross link. The application range of the aspect which a control shaft slides by one cross link becomes wide. Therefore, this tractor can control the tilling depth appropriately.

The figure which shows a tractor. The figure which shows the main structure of a tractor. The figure which shows a tilling work machine. The figure which shows the condition which a rear cover rotates according to a tillage depth. The figure which shows a working machine traction apparatus. The figure which shows the inclination operation of a tilling work machine. The figure which shows the raising / lowering operation of a tilling work machine. The figure which shows the hydraulic circuit which enables inclination operation and raising / lowering operation. BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the working-machine lifting device which concerns on 1st embodiment. The figure which shows the link unit which comprises a working-machine lifting device. The figure which shows the 1st link mechanism and 2nd link mechanism which comprise a link unit. The figure which shows the 1st link mechanism and 2nd link mechanism which comprise a link unit. The figure seen from arrow Tv of FIG.11 and FIG.12. The figure seen from the arrow Fv of FIG.11 and FIG.12. The figure which shows the operation | movement aspect of a 1st link mechanism. The figure which shows the operation | movement aspect of a 1st link mechanism. The figure which shows operation | movement of a link arm and an idle arm. The figure which shows the operation | movement aspect of a 2nd link mechanism. The figure which shows the operation | movement aspect of a 2nd link mechanism. The figure which shows operation | movement of a cam plate and a cam follower. The figure which shows operation | movement of a cam plate and an idle arm. The figure which shows the relationship between the inclination angle of an auto lever, and a tillage depth. The figure which shows the working-machine lifting device which concerns on 2nd embodiment. The figure which shows the link unit which comprises a working-machine lifting device. The figure which shows the 1st link mechanism and 2nd link mechanism which comprise a link unit. The figure which shows the 1st link mechanism and 2nd link mechanism which comprise a link unit.

  First, the tractor 1 will be briefly described.

  FIG. 1 shows a tractor 1. FIG. 2 shows the main structure of the tractor 1. In the figure, the front-back direction, the left-right direction, and the up-down direction of the tractor 1 are represented.

  The tractor 1 mainly includes a frame 11, an engine 12, a transmission 13, a front axle 14, and a rear axle 15. The tractor 1 also includes a cabin 16.

  The frame 11 forms a framework at the front of the tractor 1. The frame 11 constitutes a chassis of the tractor 1 together with the transmission 13 and the rear axle 15. The engine 12 described below is supported by the frame 11.

  The engine 12 converts thermal energy obtained by burning the fuel into kinetic energy. That is, the engine 12 generates rotational power by burning fuel. A control device is connected to the engine 12. When the operator operates an accelerator pedal or the like, the control device changes the operating state of the engine 12 according to the operation.

  The transmission 13 transmits the rotational power of the engine 12 to the front axle 14 and the rear axle 15. The rotational power of the engine 12 is input to the transmission 13 via a clutch. The transmission 13 is provided with a work implement drive device. When the operator operates the switch, the work implement drive device inputs rotational power to a work implement (such as a cultivating work implement 2 described later) to be towed.

  The front axle 14 transmits rotational power of the engine 12 to the front tire 141. The rotational power of the engine 12 is input to the front axle 14 via the transmission 13. A steering device is juxtaposed on the front axle 14. The steering device changes the steering angle of the front tire 141 according to the operation when the operator operates the steering wheel.

  The rear axle 15 transmits the rotational power of the engine 12 to the rear tire 151. The rotational power of the engine 12 is input to the rear axle 15 via the transmission 13. The rear axle 15 incorporates a braking device. The braking device reduces or stops the rotational speed of the rear tire 151 according to the operation when the operator operates the brake pedal. Further, when the operator operates the steering wheel, the braking device can also decrease or stop the rotational speed of one rear tire 151 according to the operation.

  Next, the tilling work machine 2 will be briefly described.

  FIG. 3 shows the tilling machine 2. FIG. 4 shows the situation in which the rear cover 23 pivots according to the tilling depth D. In the figure, the front-back direction, the left-right direction, and the up-down direction of the tractor 1 are represented.

  The tilling machine 2 includes a rotary 21, a rotary cover 22, a rear cover 23, a gear unit 24, and a feedback unit 25.

  The rotary 21 is a structure in which a plurality of tine 21t is attached around the rotation axis. The rotary 21 is supported parallel to the left and right direction, and cultivates the field by rotating.

  The rotary cover 22 is a structure having a cover plate 22p formed in an arc shape. The rotary cover 22 is disposed along the rotary 21 and covers the upper side of the rotary 21.

  The rear cover 23 is a structure having a cover plate 23p formed in an arc shape. The rear cover 23 is disposed so that the front side thereof follows the rotary 21 and covers the rear of the rotary 21. Further, the rear cover 23 is formed in an arc shape so that the rear side follows the field, and the surface of the field is smoothed. The rear cover 23 is pivotable about a hinge 22 h provided on the rotary cover 22.

  The gear unit 24 is a structure in which a plurality of gears are accommodated inside the case 24c. The gear unit 24 is supported by the left and right pipe cases 24p, and transmits rotational power to the rotary 21 via a drive shaft passing through the inside of the pipe cases 24p. The gear unit 24 is disposed at the center in the left-right direction in accordance with the position of the work implement drive device.

  The feedback unit 25 is a structure having a link rod (not shown), a push-pull wire 25w, and the like. One end of the feedback unit 25 is connected to the rear cover 23, and the other end is connected to an auto wire (not shown). The feedback unit 25 is disposed to surround the front side of the gear unit 24.

  With such a structure, when the rotary 21 sinks into the field and the rear cover 23 pivots upward (see the arrow Ra in FIG. 4A), the rear cover 23 pulls the push-pull wire 25w and the like. Then, the auto wire is pulled by the push-pull wire 25w or the like, and the feedback arm 54 (see FIG. 9) is rotated by the auto wire. Thus, the tilling work machine 2 can transmit the physical quantity (specifically, the stroke quantity) according to the tillage depth D by rotating the rear cover 23 upward.

  On the other hand, when the rotary 21 floats up to the field and the rear cover 23 pivots downward (see the arrow Rb in FIG. 4B), the rear cover 23 pushes the push-pull wire 25w or the like. Then, the auto wire is pushed by the push-pull wire 25w or the like, and the feedback arm 54 (see FIG. 9) is rotated by the auto wire. Thus, the tilling work machine 2 can transmit the physical quantity (specifically, the stroke quantity) according to the tillage depth D by the rear cover 23 rotating downward.

  Next, the work implement pulling device 17 that constitutes the tractor 1 will be described. The work implement traction device 17 is provided at the rear of the transmission 13 (see FIG. 2).

  FIG. 5 shows the work implement traction device 17. FIG. 6 shows the tilting operation of the tilling machine 2. Moreover, FIG. 7 has shown raising / lowering operation | movement of the tilling work machine 2. As shown in FIG. In the figure, the front-back direction, the left-right direction, and the up-down direction of the tractor 1 are represented. In addition, FIG. 8 shows a hydraulic circuit that enables tilting and raising and lowering operations.

  The work implement traction device 17 includes a top bracket 171, a top link 172, a lower bracket 173, a lower link 174, a lift arm 175, a lift link 176, an inclination actuator 177, and an elevation actuator ("hydraulic actuator" (Corresponds to 178), and.

  The top bracket 171 is attached to the rear of the transmission 13 (more precisely, the rear of the work implement lifting device 18 described later: see FIG. 9). The top bracket 171 has a hinge portion in which two plates are arranged in parallel. The hinge portion is provided with pin holes penetrating two plates in the horizontal direction.

  The top link 172 is attached to the hinge portion of the top bracket 171. The top link 172 is rotatably coupled about the pin P1 by inserting the pin P1 in a state where the pin hole of the clevis attached to the base end and the pin hole of the top bracket 171 overlap each other. ing. The top link 172 is rotated about the pin P2 by inserting the pin P2 in a state where the pin hole of the clevis attached to the tip and the pin hole of the hitch member (not shown) overlap. It is connected freely. The tilling work machine 2 is hooked on the hook of the hitch member.

  The lower bracket 173 is attached to the lower part of the transmission 13. The lower bracket 173 has a hinge portion in which two plates are arranged in parallel. The hinge portion is provided with pin holes penetrating two plates in the horizontal direction.

  The lower link 174 is attached to the hinge portion of the lower bracket 173. The lower link 174 is rotatably connected about the pin by inserting a pin (not shown) in a state where the pin hole provided at the base end and the pin hole of the lower bracket 173 overlap. ing. Further, the lower link 174 is rotatably coupled about the rod by hooking a hook 17F provided at the tip end with the rod of the hitch member. In the tilling work machine 2, the rod and the slit of the hitch member are fitted and fixed.

  The lift arm 175 is attached to the side of the transmission 13 (more precisely, the side of the work implement lifting device 18 described later: see FIG. 9). The lift arm 175 is rotatably supported centering on the lifting shaft 811 by fitting the lifting shaft 811 in a shaft hole provided at the base end. Also, the lift arm 175 has a rod fitted at its tip, and a universal joint (not shown) is attached to the rod.

  The lift link 176 is attached to the left lift arm 175 and the lower link 174. The lift link 176 is pivotable about the pin by inserting a pin (not shown) in a state where the pin hole of the clevis attached to the base end and the pin hole of the universal joint overlap. It is connected. Further, the lift link 176 is rotatable around the pin by inserting a pin (not shown) in a state where the pin hole of the clevis attached to the tip end and the pin hole of the lower link 174 overlap. Is linked to

  The tilt actuator 177 is attached to the right lift arm 175 and the lower link 174. The tilt actuator 177 is rotatable about the pin by inserting a pin (not shown) with the pin hole of the clevis attached to the cylinder case and the pin hole of the universal joint superimposed. It is connected. Further, the tilt actuator 177 rotates about the pin by inserting a pin (not shown) in a state where the pin hole of the clevis attached to the piston rod and the pin hole of the lower link 174 overlap. It is freely connected.

  The lift actuator 178 is attached to the top of the transmission 13. The lift actuator 178 has a cylinder case 181 (see FIG. 9) formed on the upper cover of the transmission 13 and is integrated as a part of the transmission 13. The lifting actuator 178 has a pivot pin attached to the piston rod, and the pivot pin abuts on a pivot arm attached to the lifting shaft 811.

  With such a structure, when the piston rod of the tilt actuator 177 slides and is pushed out (when the tilt actuator 177 extends), only the right lower link 174 to which the tilt actuator 177 is attached is pivoted downward. It will be done. Then, while the lower link 174 on the left side is maintained as it is, the lower link 174 on the right side is pushed down, so the tilling machine 2 tilts downward to the right (see arrow Rc in FIG. 6A). Therefore, if such an operation is realized in a situation where the tractor 1 is inclined to the left, the tilling work machine 2 is maintained in the horizontal state.

  On the other hand, when the piston rod of the tilt actuator 177 is slid and retracted (when the tilt actuator 177 is contracted), only the right lower link 174 to which the tilt actuator 177 is attached is pivoted upward. Become. Then, while the lower link 174 on the left side is maintained as it is, since the lower link 174 on the right side is pulled up, the tilling work machine 2 tilts upward to the right (see the arrow Rd in FIG. 6B). Therefore, if such an operation is realized in a situation where the tractor 1 is inclined to the right, the tilling work machine 2 is maintained in the horizontal state.

  In addition, when the piston rod of the lifting actuator 178 slides and is pushed out (when the lifting actuator 178 extends), the lift arm 175 is pivoted upward. Then, since the lift arm 175 pulls up the left and right lower links 174 via the lift link 176 and the tilt actuator 177, the height position of the tilling machine 2 is increased (see the arrow Re in FIG. 7A). Therefore, if this operation is realized in the situation where the tilling work machine 2 sinks, the tilling depth will be maintained in a constant state.

  On the other hand, when the piston rod of the lifting actuator 178 slides and is retracted (when the lifting actuator 178 is contracted), the lift arm 175 is pivoted downward. Then, the lift arm 175 pushes down the left and right lower links 174 via the lift link 176 and the tilt actuator 177, so that the height position of the tilling machine 2 is lowered (see the arrow Rf in FIG. 7B). Therefore, if this operation is realized in a state where the tilling work machine 2 is lifted, the tilling depth will be maintained in a constant state.

  The lifting actuator 178 is also operated by the operation of the position lever 31 and the auto lever 32. The position lever 31 can set the height position of the tilling work machine 2 by operating the lifting and lowering actuator 178 via the link unit 3. The automatic lever 32 can set the tilling depth D of the tilling machine 2 by operating the lifting and lowering actuator 178 via the link unit 3. The hydraulic circuit is provided with a configuration that can realize such a function.

  Next, the work implement lifting device 18 constituting the tractor 1 will be described. The work implement lifting device 18 is provided on the top of the transmission 13 (see FIG. 2).

  FIG. 9 shows the work implement lifting device 18 according to the first embodiment. FIG. 10 shows the link unit 3 that constitutes the work implement lifting device 18. 11 and 12 show a first link mechanism 4 and a second link mechanism 5 which constitute the link unit 3. Furthermore, FIG. 13 is a view from arrow Tv in FIGS. 11 and 12, and FIG. 14 is a view from arrow Fv in FIGS. In the figure, the front-back direction, the left-right direction, and the up-down direction of the tractor 1 are represented.

  The work implement lifting device 18 includes a lifting actuator 178. The lifting actuator 178 is configured of a cylinder case 181, a cylinder head 182, and a piston 183. In addition, the work implement lifting device 18 includes a tilting valve unit 184 and a lifting valve unit 185. Accordingly, the work implement lifting device 18 includes a cylinder case 181, a cylinder head 182, a piston 183, a tilting valve unit 184, and a lifting valve unit 185.

  The cylinder case 181 is a main structure of the work implement lifting device 18. The cylinder case 181 has a mounting seat surface of the cylinder head 182 formed on its front surface. Further, a mounting seat surface of the top bracket 171 is formed on the rear surface of the cylinder case 181. Further, a mounting seat surface of the elevating valve unit 185 is formed on the lower surface of the cylinder case 181. The cylinder case 181 is provided with shaft holes on both side surfaces thereof, and the lifting shaft 811 is inserted into the shaft holes.

  The cylinder head 182 is fixed to the front surface of the cylinder case 181. The cylinder head 182 is provided at its front surface with a mounting seat of a cap plate. Further, a mounting seat surface of the cylinder case 181 is formed on the rear surface of the cylinder head 182. Further, the cylinder head 182 has a mounting seat surface of the inclination valve unit 184 formed on the right surface thereof. The cylinder head 182 is provided with a shaft hole passing therethrough, and the shaft of the return handle 821 is inserted into the shaft hole.

  The piston 183 is accommodated inside the cylinder case 181. The piston 183 has a concave surface on its front surface to receive the pressure of the hydraulic fluid. Also, the piston 183 has a concave surface formed on its rear surface to support the piston rod. Further, the piston 183 has a plurality of oil rings fitted on its circumferential surface. The piston 183 is accommodated in a cylinder sleeve fitted in a cylinder case 181, and is slidable along the cylinder sleeve.

  The tilt valve unit 184 is fixed to the right surface of the cylinder head 182. The inclination valve unit 184 includes a diversion valve. The diversion valve opens and closes the port hole by sliding of the poppet to switch the flow direction of the hydraulic oil. In addition, the inclination valve unit 184 includes a direction switching valve. The direction switching valve changes the port hole communicated by the sliding of the spool, and switches the flow direction of the hydraulic oil. The tilt valve unit 184 guides the hydraulic fluid to the tilt actuator 177 via an oil passage (not shown).

  The lift valve unit 185 is fixed to the lower surface of the cylinder case 181. The lift valve unit 185 includes a first switching valve. The first switching valve changes the port hole communicated by the sliding of the spool and switches the flow direction of the hydraulic oil. In addition, the lifting valve unit 185 includes a second switching valve. The second switching valve changes the port hole communicated by the sliding of the spool and switches the flow direction of the hydraulic oil. The elevating valve unit 185 guides the hydraulic oil to the elevating actuator 178 via an oil passage (not shown). Further, the elevating valve unit 185 includes a spring 851 and always biases a control shaft 33 described later to one side (see arrow F in FIGS. 11 and 12).

  Furthermore, the work implement lifting device 18 includes the link unit 3. The link unit 3 has a position lever 31 and an auto lever 32. Further, the link unit 3 has a first link mechanism 4 which is a link mechanism on the side of the position lever 31 and a second link mechanism 5 which is a link mechanism on the side of the auto lever 32.

  The position lever 31 is rotatably supported centering on the support shaft Ca. A push-pull wire 31w is connected to the position lever 31, and the first link mechanism 4 can be moved via the push-pull wire 31w. The position lever 31 is disposed to the right of the driver's seat. Therefore, the operator can hold and operate the position lever 31 with the right hand. The operator needs to bring the position lever 31 into the most depressed state (the most inclined state to the arrow R side in FIG. 10) before starting the tilling operation.

  The auto lever 32 is rotatably supported about a support shaft Cb. A push-pull wire 32w is connected to the auto lever 32, and the second link mechanism 5 can be moved via the push-pull wire 32w. The auto lever 32 is also disposed to the right of the driver's seat. Therefore, the operator can hold and operate the auto lever 32 with the right hand. The operator needs to be in a state where the automatic lever 32 is pushed down to an arbitrary position (in a state of being appropriately inclined to the arrow T side in FIG. 10) before starting the tilling operation. The tillage depth D is determined in accordance with the tilt angle of the auto lever 32.

  The first link mechanism 4 moves the elevating valve unit 185 according to the operation of the position lever 31. That is, in response to the operation of the position lever 31, the first link mechanism 4 actuates the lifting and lowering actuator 178. The first link mechanism 4 includes a link arm 41, an idle arm 42, a right inner shaft (corresponding to a "first shaft") 43, a feedback arm 44, a left inner shaft 45, and an upper cross link (" 46) corresponding to “one cross link”.

  The link arm 41 is rotatably supported about a support shaft Cc. Specifically, the link arm 41 has a sleeve and is supported by the right inner shaft 43 inserted in the sleeve. Therefore, the link arm 41 pivots independently from the right inner shaft 43 about the right inner shaft 43. When the position lever 31 is pushed down, the link arm 41 is pushed by the push-pull wire 31 w and pivots in one direction (see arrow A in FIG. 15). Further, when the position lever 31 is pulled up, the link arm 41 is pulled by the push-pull wire 31 w and rotates to the other (see arrow B in FIG. 16). In addition, the link arm 41 is bent to form a crank 41c. Therefore, in the predetermined angle range, the idle arm 42 is in contact with the crank 41c.

  The idle arm 42 is rotatably supported about a support shaft Cc. Specifically, the idle arm 42 is formed with a mounting hole, and is supported by the right inner shaft 43 fitted in the mounting hole. Therefore, the idle arm 42 rotates around the right inner shaft 43 in a state of being integrated with the right inner shaft 43. When the link arm 41 is pivoted to one side, the idle arm 42 is pivoted to one side so as to follow the link arm 41 by the biasing force of the spring 851 (see an arrow C in FIG. 15). Further, when the link arm 41 is pivoted to the other side, the idle arm 42 is pushed by the link arm 41 and pivots to the other (see arrow D in FIG. 16). In addition, the idler arm 42 has a stopper plate 42s welded to its back surface. Therefore, in a predetermined angle range, the adjuster bolt 51A of the cam plate 51 is in contact with the stopper plate 42s.

  The right inner shaft 43 is rotatably supported about a support shaft Cc. Specifically, the right inner shaft 43 is formed in a thin cylindrical shape, and is supported in a state of being inserted into a right outer shaft 53 described later. Therefore, the right inner shaft 43 rotates with the right outer shaft 53 as a bearing. The right inner shaft 43 rotates to one side with the idle arm 42 when the idle arm 42 rotates to one side (see arrow E in FIG. 15). Further, when the idle arm 42 pivots to the other, the right inner shaft 43 pivots to the other with the idle arm 42 (see arrow F in FIG. 16). In addition, the right inner shaft 43 has a link plate 43r attached to one end thereof. Pins 43p are attached to the link plate 43r.

  The feedback arm 44 is rotatably supported about a support shaft Cd. Specifically, the feedback arm 44 is formed with a mounting hole, and is supported by the left inner shaft 45 fitted in the mounting hole. Therefore, the feedback arm 44 rotates around the left inner shaft 45 in a state integral with the left inner shaft 45. When the lift arm 175 pivots downward, the feedback arm 44 is pushed by the lift arm 175 and pivots in one direction (see arrow G in FIG. 15). Further, when the lift arm 175 pivots upward, the feedback arm 44 is pulled by the lift arm 175 and pivots to the other (see arrow H in FIG. 16). In addition, the feedback arm 44 has a stay plate 44s attached to one end thereof. A link rod 44r connected to the lift arm 175 is attached to the stay plate 44s.

  The left inner shaft 45 is rotatably supported about a support shaft Cd. Specifically, the left inner shaft 45 is formed in a thin cylindrical shape, and is supported in a state of being inserted into a left outer shaft 55 described later. Therefore, the left inner shaft 45 rotates with the left outer shaft 55 as a bearing. When the feedback arm 44 pivots to one side, the left inner shaft 45 pivots to one side with the feedback arm 44 (see arrow I in FIG. 15). Further, when the feedback arm 44 pivots to the other, the left inner shaft 45 pivots to the other with the feedback arm 44 (see arrow J in FIG. 16). In addition, the left inner shaft 45 has a link plate 45r attached to one end thereof. Pins 45p are attached to the link plate 45r.

  The upper cross link 46 is rotatably supported about a pivot Ce. Specifically, the upper cross link 46 is formed with a through hole, and is supported by a rivet pin 33 r inserted in the through hole. Therefore, the upper cross link 46 pivots about the rivet pin 33r. Moreover, the rivet pin 33r is attached in the state which penetrated the control shaft 33 in the up-down direction. Accordingly, the upper cross link 46 pivots independently of the control shaft 33. When the right inner shaft 43 pivots in one direction, the upper cross link 46 pivots in one direction so that the right bent portion 46b follows the pin 43p by the biasing force of the spring 851 (see arrow K in FIG. 15). ). At this time, the control shaft 33 slides rearward (see the arrow M in FIG. 15). In the upper cross link 46, when the right inner shaft 43 pivots to the other, the right bent portion 46b is pushed by the pin 43p and pivots to the other (see arrow L in FIG. 16). At this time, the control shaft 33 slides forward (see the arrow N in FIG. 16). Furthermore, in the upper cross link 46, when the left inner shaft 45 is pivoted to one side, the left bent portion 46b is pushed by the pin 45p and pivots to one side (see arrow K in FIG. 16). At this time, the control shaft 33 slides forward (see the arrow N in FIG. 16). Further, when the left inner shaft 46 is rotated to the other side, the upper cross link 46 is rotated to the other side by the biasing force of the spring 851 so that the left bent portion 46b follows the pin 45p (see arrow L in FIG. 15). ). At this time, the control shaft 33 slides rearward (see the arrow M in FIG. 15). The elevating valve unit 185 moves in accordance with the sliding position of the control shaft 33. In other words, the lift actuator 178 operates in accordance with the sliding position of the control shaft 33.

  The second link mechanism 5 moves the elevating valve unit 185 according to the operation of the auto lever 32. That is, the second link mechanism 5 operates the lifting and lowering actuator 178 in response to the operation of the auto lever 32. The second link mechanism 5 includes a cam plate 51, a cam follower 52, a right outer shaft (corresponding to a "second shaft") 53, a feedback arm 54, a left outer shaft 55, and a lower cross link (" 2) corresponding to “cross link” 56).

  The cam plate 51 is rotatably supported about a support shaft Cf. Specifically, the cam plate 51 has a sleeve and is supported by a rivet pin 51r inserted in the sleeve. Therefore, the cam plate 51 rotates about the rivet pin 51r. When the auto lever 32 is pushed down, the cam plate 51 is pushed by the push-pull wire 32 w and pivots to one side (see arrow A in FIG. 18). Further, when the auto lever 32 is pulled up, the cam plate 51 is pulled by the push-pull wire 32 w and pivots to the other (see arrow B in FIG. 19). In addition, a stay is welded to the surface of the cam plate 51 to support the adjuster bolt 51A. Therefore, in the predetermined angle range, the stopper plate 42s of the idle arm 42 is in contact with the adjuster bolt 51A.

  The cam follower 52 is rotatably supported about a support shaft Cc. Specifically, the cam follower 52 has a sleeve and is supported by a right outer shaft 53 fitted in the sleeve. Therefore, the cam follower 52 rotates around the right outer shaft 53 in a state integrated with the right outer shaft 53. When the cam plate 51 is pivoted to one side, the cam follower 52 is guided by the cam plate 51 to pivot to one side (see arrow C in FIG. 18). Further, when the cam plate 51 is rotated to the other side, the cam follower 52 is guided by the cam plate 51 to rotate to the other side (see arrow D in FIG. 19). In addition, the cam follower 52 has a roller 52R attached to one end thereof. The roller 52R is in contact with the cam face 51C of the cam plate 51 (see FIG. 20).

  The right outer shaft 53 is rotatably supported about a support shaft Cc. Specifically, the right outer shaft 53 is formed in a cylindrical shape, and is rotatably supported in a state in which the right inner shaft 43 described above is inserted. Therefore, the right outer shaft 53 rotates in a state in which the right inner shaft 43 is supported. When the cam follower 52 is pivoted to one side, the right outer shaft 53 is pivoted to one side with the cam follower 52 (see arrow E in FIG. 18). Further, when the cam follower 52 rotates to the other side, the right outer shaft 53 rotates to the other side with the cam follower 52 (see arrow F in FIG. 19). In addition, the right outer shaft 53 has a link plate 53r welded to its midway portion. Pins 53p are attached to the link plate 53r.

  The feedback arm 54 is rotatably supported about the support shaft Cd. Specifically, the feedback arm 54 has a sleeve and is rotatably supported by the left outer shaft 55 fitted in the sleeve. Therefore, the feedback arm 54 pivots around the left outer shaft 55 in a state integral with the left outer shaft 55. When the rear cover 23 pivots upward, the feedback arm 54 is pulled by the auto wire and pivots in one direction (see arrow G in FIG. 18). Further, when the rear cover 23 pivots downward, the feedback arm 54 is pushed by the auto wire and pivots to the other (see the arrow H in FIG. 19). In addition, the feedback arm 54 has a link rod 54r attached thereto. A stay plate 54s connected to an auto wire is attached to the link rod 54r.

  The left outer shaft 55 is rotatably supported about a support shaft Cd. Specifically, the left outer shaft 55 is formed in a cylindrical shape, and is rotatably supported in a state where the left inner shaft 45 described above is inserted. Therefore, the left outer shaft 55 rotates in a state in which the left inner shaft 45 is supported. When the feedback arm 54 pivots to one side, the left outer shaft 55 pivots to one side with the feedback arm 54 (see arrow I in FIG. 18). Further, when the feedback arm 54 is pivoted to the other side, the left outer shaft 55 is pivoted to the other side with the feedback arm 54 (see arrow J in FIG. 19). In addition, the left outer shaft 55 has a link plate 55r welded to its midway portion. Pins 55p are attached to the link plate 55r.

  The lower cross link 56 is rotatably supported around a pivot Ce. Specifically, the lower cross link 56 is formed with a through hole and is supported by the rivet pin 33 r inserted in the through hole. Therefore, the lower cross link 56 pivots about the rivet pin 33r. Moreover, the rivet pin 33r is attached in the state which penetrated the control shaft 33 in the up-down direction. Accordingly, the lower cross link 56 pivots independently of the control shaft 33. When the right outer shaft 53 turns to one side, the lower cross link 56 turns to one side so that the right bent portion 56b follows the pin 53p by the biasing force of the spring 851 (arrow K in FIG. 18). reference). At this time, the control shaft 33 slides rearward (see arrow M in FIG. 18). In the lower cross link 56, when the right outer shaft 53 pivots to the other, the right bent portion 56b is pushed by the pin 53p and pivots to the other (see arrow L in FIG. 19). At this time, the control shaft 33 slides forward (see the arrow N in FIG. 19). Furthermore, in the lower cross link 56, when the left outer shaft 55 pivots in one direction, the left bent portion 56b is pushed by the pin 55p and pivots in one direction (see arrow K in FIG. 19). At this time, the control shaft 33 slides forward (see the arrow N in FIG. 19). Further, when the left outer shaft 56 is rotated to the other side, the lower cross link 56 is rotated to the other side so that the left bent portion 56b follows the pin 55p by the biasing force of the spring 851 (arrow L in FIG. 18). reference). At this time, the control shaft 33 slides rearward (see arrow M in FIG. 18). The elevating valve unit 185 moves in accordance with the sliding position of the control shaft 33. In other words, the lift actuator 178 operates in accordance with the sliding position of the control shaft 33.

  Next, a series of operations by the operation of the position lever 31 will be described.

  15 and 16 show the operation mode of the first link mechanism 4. FIG. 17 shows the operation of the link arm 41 and the idle arm 42.

  First, the case where the position lever 31 is pushed down (when inclined to the arrow R side in FIG. 10) will be described.

  When the position lever 31 is depressed, the link arm 41 is pushed by the push-pull wire 31w and pivots to one side (see arrow A in FIG. 15). The idle arm 42 pivots to one side so as to follow the link arm 41 by the biasing force of the spring 851 (see arrow C in FIG. 15). Then, the right inner shaft 43 rotates to one side with the idle arm 42 (see arrow E in FIG. 15), and the upper cross link 46 is such that the right bent portion 46b follows the pin 43p by the biasing force of the spring 851. It turns to one side (see arrow K in FIG. 15). Thus, the control shaft 33 slides rearward (see the arrow M in FIG. 15). Although the link arm 41 and the idle arm 42 integrally rotate halfway (see FIGS. 17A to 17B), only the link arm 41 rotates halfway (from FIG. 17B). (C)). This is because the stopper plate 42s of the idle arm 42 abuts on the adjuster bolt 51A.

  As described above, when the position lever 31 is pushed down, the control shaft 33 finally slides rearward. When the control shaft 33 slides backward, the elevating valve unit 185 moves, and the piston rod of the elevating actuator 178 slides in and is retracted (the elevating actuator 178 contracts). Then, the lift arm 175 pivots downward, and the lift link 176 and the tilt actuator 177 push down the left and right lower links 174, so that the height position of the tilling machine 2 is lowered (arrow in FIG. 7 (B) See Rf).

  Next, the case where the position lever 31 is pulled up (when standing up to the arrow S side in FIG. 10) will be described.

  When the position lever 31 is pulled up, the link arm 41 is pulled by the push-pull wire 31w and pivots to the other (see arrow B in FIG. 16). The idle arm 42 is pushed by the link arm 41 and pivots to the other (see arrow D in FIG. 16). Then, the right inner shaft 43 rotates with the idle arm 42 to the other (see arrow F in FIG. 16), and the upper cross link 46 rotates to the other as the right bent portion 46b is pushed by the pin 43p ( See arrow L in FIG. Thus, the control shaft 33 slides forward (see arrow N in FIG. 16). Note that although the link arm 41 pivots alone halfway (see FIGS. 17C to 17B), the link arm 41 pivots integrally with the idle arm 42 halfway (FIGS. 17B to 17A). reference). This is because the crank portion 41 c of the link arm 41 abuts on the idle arm 42.

  Thus, when the position lever 31 is pulled up, the control shaft 33 finally slides forward. When the control shaft 33 slides forward, the lift valve unit 185 moves, and the piston rod of the lift actuator 178 slides and is pushed out (the lift actuator 178 extends). Then, the lift arm 175 pivots upward, and the lift link 176 and the tilting actuator 177 pull up the left and right lower links 174, so that the height position of the tilling work machine 2 becomes high (arrow in FIG. 7A). Re)).

  Next, a series of operations by the operation of the auto lever 32 will be described.

  18 and 19 show the operation mode of the second link mechanism 5. FIG. 20 shows the operation of the cam plate 51 and the cam follower 52. FIG. 21 shows the operation of the cam plate 51 and the idle arm 42. FIG. 22 shows the relationship between the tilt angle α of the auto lever 32 and the tillage depth D.

  First, the case where the auto lever 32 is pushed down (when it is tilted to the arrow T side in FIG. 10) will be described.

  When the auto lever 32 is pushed down, the cam plate 51 is pushed by the push-pull wire 32 w and pivots to one side (see arrow A in FIG. 18). The cam follower 52 is guided by the cam plate 51 and pivots to one side (see arrow C in FIG. 18). Then, the right outer shaft 53 rotates to one side with the cam follower 52 (see arrow E in FIG. 18), and the lower cross link 56 is such that the right bent portion 56b follows the pin 53p by the biasing force of the spring 851. It turns to one side (see arrow K in FIG. 18). Thus, the control shaft 33 slides rearward (see arrow M in FIG. 18). When the roller 52R of the cam follower 52 is in contact with the first cam area 51Ca of the cam plate 51, the rotation angle of the right outer shaft 53 is small (see FIGS. 20A to 20B), and the second cam area 51Cb When the roller 52R is in contact with the roller 52R, the rotation angle of the right outer shaft 532 is increased (see FIGS. 20B to 20C). This is an arc shape in which the first cam region 51Ca is gradually bent in a substantially radial direction from the substantially circumferential direction around the support shaft Cc, and the second cam region 51Cb is substantially in the radial direction around the support shaft Cc It is because it becomes an arc shape which is gradually bent in a substantially circumferential direction. Therefore, the amount of change in the tillage depth D gradually increases with the operation of tilting the auto lever 32 (see the arrow Gu in FIG. 22). Further, although the cam plate 51 and the idle arm 42 integrally rotate halfway (see FIGS. 21 (A) to (B)), only the cam plate 51 is rotated halfway (from FIG. 21 (B) (C)). This is because the idle arm 42 abuts on the crank portion 41 c of the link arm 41. Therefore, a singular point appears in the change of the tillage depth D before and after the auto lever 32 reaches the predetermined tilt angle (see point Sp in FIG. 22).

  As described above, when the auto lever 32 is depressed, the control shaft 33 finally slides rearward. However, in a situation where the cam plate 51 and the idle arm 42 are integrally rotated, the first link mechanism 4 cooperates with the second link mechanism 5 to slide the control shaft 33 rearward. Further, in a situation where only the cam plate 51 is rotating, the control shaft 33 is slid rearward by the second link mechanism 5. Furthermore, regardless of the situation, the second link mechanism 5 slides the control shaft 33 rearward based on the cam profile of the cam plate 51. When the control shaft 33 slides backward, the elevating valve unit 185 moves, and the piston rod of the elevating actuator 178 slides in and is retracted (the elevating actuator 178 contracts). Then, the lift arm 175 pivots downward, and the lift link 176 and the tilt actuator 177 push down the left and right lower links 174, so that the height position of the tilling machine 2 is lowered (arrow in FIG. 7 (B) See Rf).

  Next, the case where the automatic lever 32 is pulled up (when standing up to the arrow U side in FIG. 10) will be described.

  When the auto lever 32 is pulled up, the cam plate 51 is pulled by the push-pull wire 32 w and pivots to the other (see arrow B in FIG. 19). The cam follower 52 is guided by the cam plate 51 and pivots to the other (see arrow D in FIG. 19). Then, the right outer shaft 53 rotates with the cam follower 52 to the other (see arrow F in FIG. 19), and the lower cross link 56 rotates to the other as the right bent portion 56b is pushed by the pin 53p ( See arrow L in FIG. Thus, the control shaft 33 slides forward (see arrow N in FIG. 19). When the roller 52R of the cam follower 52 is in contact with the second cam area 51Cb of the cam plate 51, the rotation angle of the right outer shaft 53 is large (see FIGS. 20C and 20B), and the first cam area 51Ca When the roller 52R is in contact with the roller 52R, the rotation angle of the right outer shaft 53 is reduced (see FIGS. 20B to 20A). This is an arc shape in which the second cam region 51Cb is gradually bent in a substantially radial direction from the substantially circumferential direction around the support shaft Cc, and the first cam region 51Ca is substantially in the shape direction around the support shaft Cc It is because it becomes an arc shape which is gradually bent in a substantially circumferential direction. Therefore, the amount of change in the tillage depth D gradually decreases with the operation of raising the automatic lever 32 (see the arrow Gd in FIG. 22). In addition, although the cam plate 51 is independently rotated halfway (see FIGS. 21C to 21B), the cam plate 51 integrally rotates with the idle arm 42 in the middle (FIGS. 21B to 21A). reference). This is because the adjuster bolt 51A is in contact with the stopper plate 42s of the idle arm 42. Therefore, a singular point appears in the change of the tillage depth D before and after the auto lever 32 reaches the predetermined tilt angle (see point Sp in FIG. 22).

  As described above, when the automatic lever 32 is pulled up, the control shaft 33 finally slides forward. However, in a situation where only the cam plate 51 is rotating, the control shaft 33 is slid rearward by the second link mechanism 5. Further, in a situation where the cam plate 51 and the idle arm 42 are integrally pivoted, the first link mechanism 4 cooperates with the second link mechanism 5 to slide the control shaft 33 rearward. Furthermore, regardless of the situation, the second link mechanism 5 slides the control shaft 33 rearward based on the cam profile of the cam plate 51. When the control shaft 33 slides forward, the lift valve unit 185 moves, and the piston rod of the lift actuator 178 slides and is pushed out (the lift actuator 178 extends). Then, the lift arm 175 pivots upward, and the lift link 176 and the tilting actuator 177 pull up the left and right lower links 174, so that the height position of the tilling work machine 2 becomes high (arrow in FIG. 7A). Re)).

  The feature points of the tractor 1 are summarized below.

  The first feature point is the technical idea in the area Ra of FIG.

  The tractor 1 includes a cam plate 51 rotated by an automatic lever 32, and a cam follower 52 attached to the second shaft (right outer shaft 53) in contact with the cam plate 51. Then, when the auto lever 32 is operated, the cam follower 52 is guided by the cam plate 51, the second shaft (right outer shaft 53) interlocks, and the control shaft 33 slides by the second cross link (lower cross link 56). Do. Thus, the present tractor 1 is a hydraulic actuator (lifting actuator 178) for the operation amount of the auto lever 32, based on the cam profile of the cam plate 51 that constitutes the link mechanism (second link mechanism 5) on the auto lever 32 side. The amount of actuation of the That is, in the present tractor 1, the displacement amount of the tillage depth D with respect to the operation amount of the auto lever 32 is determined based on the cam profile of the cam plate 51 constituting the link mechanism (second link mechanism 5) on the auto lever 32 side. Be done. Therefore, the tractor 1 can control the tilling depth D appropriately.

  The second feature point is the technical idea when the automatic lever 32 is depressed in the region Rb of FIG.

  The tractor 1 includes an idle arm 42 attached to the first shaft (right inner shaft 43). Then, when the auto lever 32 is operated to one side, the idle arm 42 is guided by the cam plate 51, the first shaft (right inner shaft 43) interlocks, and in addition to the second cross link (lower cross link 56) The control shaft 33 slides by one cross link (upper cross link 46). As a result, in the tractor 1, the link mechanism (first link mechanism 4) on the position lever 31 side cooperates with the link mechanism (second link mechanism 5) on the automatic lever 32 side in a region where the tilt angle of the auto lever 32 is small. Thus, the amount of operation of the hydraulic actuator (lifting actuator 178) relative to the amount of operation of the auto lever 32 is determined. That is, in this tractor 1, the link mechanism (first link mechanism 4) on the position lever 31 side cooperates with the link mechanism (second link mechanism 5) on the automatic lever 32 side in a region where the tilt angle of the auto lever 32 is small. The amount of displacement of the tillage depth D with respect to the amount of operation of the automatic lever 32 is determined. Therefore, the tractor 1 can control the tilling depth D appropriately.

  The third feature point is the technical idea when the automatic lever 32 is depressed in the region Rc of FIG.

  In the tractor 1, when the auto lever 32 is operated further to one side, the cam plate 51 separates from the idle arm 42, and the control shaft 33 slides by only the second cross link (lower cross link 56). As a result, in the tractor 1, the link mechanism (second link mechanism 5) on the side of the auto lever 32 in the region where the tilt angle of the auto lever 32 is large, the hydraulic actuator (lifting actuator 178) for the operation amount of the auto lever 32. The operating amount is determined. That is, in this tractor 1, the displacement amount of the tillage depth D with respect to the operation amount of the auto lever 32 is determined by the link mechanism (second link mechanism 5) on the auto lever 32 side in the region where the tilt angle of the auto lever 32 is large. Ru. Therefore, the tractor 1 can control the tilling depth D appropriately.

  The fourth feature point is the technical idea in the case where the automatic lever 32 is pulled up in the region Rc of FIG.

  The tractor 1 includes an idle arm 42 attached to the first shaft (right inner shaft 43). Then, when the auto lever 32 is operated to the other side, the cam plate 51 approaches the idle arm 42, and the control shaft 33 slides by only the second cross link (lower cross link 56). As a result, in the tractor 1, the link mechanism (second link mechanism 5) on the side of the auto lever 32 in the region where the tilt angle of the auto lever 32 is large, the hydraulic actuator (lifting actuator 178) for the operation amount of the auto lever 32. The operating amount is determined. That is, in this tractor 1, the displacement amount of the tillage depth D with respect to the operation amount of the auto lever 32 is determined by the link mechanism (second link mechanism 5) on the auto lever 32 side in the region where the tilt angle of the auto lever 32 is large. Ru. Therefore, the tractor 1 can control the tilling depth D appropriately.

  The fifth feature point is the technical idea in the case where the automatic lever 32 is pulled up in the region Rb of FIG.

  When the automatic lever 32 is further operated to the other side, the idle arm 42 is pushed by the cam plate 51 and the first shaft (right inner shaft 43) interlocks with the second cross link (the lower cross link 56). In addition to the above, the first cross link (upper cross link 46) slides the control shaft 33. As a result, in the tractor 1, the link mechanism (first link mechanism 4) on the position lever 31 side cooperates with the link mechanism (second link mechanism 5) on the automatic lever 32 side in a region where the tilt angle of the auto lever 32 is small. Thus, the amount of operation of the hydraulic actuator (lifting actuator 178) relative to the amount of operation of the auto lever 32 is determined. That is, in this tractor 1, the link mechanism (first link mechanism 4) on the position lever 31 side cooperates with the link mechanism (second link mechanism 5) on the automatic lever 32 side in a region where the tilt angle of the auto lever 32 is small. The amount of displacement of the tillage depth D with respect to the amount of operation of the automatic lever 32 is determined. Therefore, the tractor 1 can control the tilling depth D appropriately.

  The sixth feature point is the technical idea in the area Ra of FIG.

  In the present tractor 1, the cam plate 51 is provided with a first cam area 51Ca and a second cam area 51Cb. Then, when the cam follower 52 is in contact with the first cam area 51Ca, when the auto lever 32 is operated, the cam follower 52 is guided by the cam plate 51 and the second shaft (right outer shaft 53) interlocks in a small amount, and the second cam area 51Cb When the cam follower 52 is in contact, operating the auto lever 32 guides the cam follower 52 to the cam plate 51 and the second shaft (right outer shaft 53) interlocks largely, and only the second cross link (lower cross link 56) Alternatively, in addition to the second cross link (lower cross link 56), the control shaft 33 slides by the first cross link (upper cross link 46). As a result, in the region where the inclination angle of the auto lever 32 is small, the tractor 1 reduces the operation amount of the hydraulic actuator (lifting actuator 178) with respect to the operation amount of the auto lever 32, and in the region where the inclination angle of the auto lever 32 is large The operation amount of the hydraulic actuator (lifting actuator 178) with respect to the operation amount of the lever 32 is increased. That is, this tractor 1 has a small displacement amount of the tillage depth D with respect to the operation amount of the auto lever 32 in a region where the tilt angle of the auto lever 32 is small, and an operation amount of the auto lever 32 in a region where the tilt angle of the auto lever 32 is large. The amount of displacement of the tillage depth D with respect to Therefore, the tractor 1 can control the tilling depth D appropriately.

  The seventh feature point is a technical idea to move the boundary between the region Rb and the region Rc in FIG.

  The tractor 1 is provided with an adjuster bolt 51A at a contact point of the cam plate 51 and the idle arm 52. Then, in addition to the second cross link (lower cross link 56), the first cross link (upper cross link 46) and the aspect in which the control shaft 33 slides only by the second cross link (lower cross link 56). The switching timing of the mode in which the control shaft 33 slides is adjustable. Thus, in the present tractor 1, when the length of the adjuster bolt 51A is shortened, a mode in which the control shaft 33 slides only by the second cross link (lower cross link 56) becomes dominant, and the length of the adjuster bolt is increased. Then, the aspect in which the control shaft 33 slides by the first cross link (upper cross link 46) in addition to the second cross link (lower cross link 56) becomes dominant. That is, if the length of the adjuster bolt 51A is shortened, the scope of application of the embodiment in which the control shaft 33 slides only by the second cross link (lower cross link 56) is widened, and the length of the adjuster bolt 51A By making the length of the control shaft 33 longer by the first cross link (upper cross link 46) in addition to the second cross link (lower cross link 56), the scope of application of the embodiment in which the control shaft 33 slides is broadened. Therefore, the tractor 1 can control the tilling depth D appropriately.

  Next, a work implement lifting device 18 according to a second embodiment will be described.

  FIG. 23 shows a work implement lifting device 18 according to the second embodiment. FIG. 24 shows the link unit 3 that constitutes the work implement lifting device 18. 25 and 26 show the first link mechanism 4 and the second link mechanism 5 which constitute the link unit 3. In the figure, the front-back direction, the left-right direction, and the up-down direction of the tractor 1 are represented.

  The working machine lifting and lowering device 18 according to the present embodiment differs in structure from the working tool lifting and lowering device 18 according to the first embodiment. However, the cam plate 51 rotated by the auto lever 32 and the cam follower 52 attached to the second shaft (right outer shaft 53) in contact with the cam plate 51 are provided. In addition, an idle arm 42 attached to the first shaft (right inner shaft 43) is provided. And the working machine lifting and lowering device 18 according to the present embodiment has the same effect as the working tool lifting and lowering device 18 according to the first embodiment.

DESCRIPTION OF SYMBOLS 1 Tractor 11 Frame 12 Engine 13 Transmission 14 Front Axle 15 Rear Axle 16 Cabin 17 Work implement traction device 18 Work implement lift device 177 Tilting actuator 178 Lifting actuator (hydraulic actuator)
2 tilling machine 3 link unit 4 first link mechanism 41 link arm 42 idle arm 43 right inner shaft (first shaft)
44 feedback arm 45 left inner shaft 46 upper cross link (first cross link)
5 second link mechanism 51 cam plate 52 cam follower 53 right outer shaft (second shaft)
54 feedback arm 55 left outer shaft 56 lower cross link (second cross link)

Claims (7)

A position lever, a first shaft interlocking with the position lever, a first cross link interlocking with the first shaft, an auto lever, a second shaft interlocking with the auto lever, and the second shaft interlocking with the second shaft A second cross link, and a control shaft rotatably supporting the first cross link and the second cross link,
In a tractor in which a hydraulic actuator operates according to a sliding position of the control shaft
A cam plate rotated by the auto lever, and a cam follower attached to the second shaft in contact with the cam plate;
When the auto lever is operated, the cam follower is guided by the cam plate to interlock the second shaft,
The control shaft is slid by the second cross link;
A tractor characterized by An idle arm attached to the first shaft;
When the auto lever is operated to one side, the idle arm is guided by the cam plate to interlock the first shaft,
The control shaft is slid by the first cross link in addition to the second cross link
The tractor according to claim 1, characterized in that. When the auto lever is further operated to one side, the cam plate is separated from the idle arm,
The control shaft slides only by the second cross link;
A tractor according to claim 2, characterized in that. An idle arm attached to the first shaft;
When the auto lever is operated to the other side, the cam plate approaches the idle arm,
The control shaft slides only by the second cross link;
The tractor according to claim 1, characterized in that. When the auto lever is further operated to the other side, the idle arm is guided by the cam plate to interlock the first shaft,
The control shaft is slid by the first cross link in addition to the second cross link
A tractor according to claim 4, characterized in that. Providing a first cam area and a second cam area on the cam plate;
When the cam follower is in contact with the first cam area,
When the auto lever is operated, the cam follower is guided by the cam plate and the second shaft interlocks in a small amount.
When the cam follower is in contact with the second cam area,
When the auto lever is operated, the cam follower is guided by the cam plate and the second shaft is largely interlocked,
The control shaft is slid by the first cross link in addition to the second cross link alone or in addition to the second cross link.
The tractor as described in any one of the Claims 1-5 characterized by the above-mentioned. An adjuster bolt is provided at a contact of the cam plate and the idle arm,
The switching timing between the mode in which the control shaft slides only by the second cross link and the mode in which the control shaft slides by the first cross link in addition to the second cross link can be adjusted.
The tractor according to claim 2 or 4 characterized by things.

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