JP5097170B2 - Tractor - Google Patents

Description

  The present invention relates to a tractor.

  Conventionally, at the rear of the tractor body, a three-point link mechanism for mounting the rear installation implement to be movable up and down, a rear installation hydraulic cylinder for moving the rear installation up and down, and the rear installation hydraulic pressure A lift control valve for controlling the cylinder and an auxiliary control valve for controlling a hydraulic actuator mounted on an implement mounted on the tractor vehicle body are provided (see Patent Document 1).

JP 2007-146945 A

In the conventional tractor, there is a case where a front implement is attached to the front portion of the vehicle body, a rear implement is attached to the rear portion of the vehicle body, and a complex operation is performed using these front and rear implements.
The implement is equipped with a hydraulically driven actuator, but some of the front implements are equipped with a hydraulic motor in addition to the hydraulic cylinder as an actuator. There was no control valve at the front of the car body that was compatible with the vehicle.

For this reason, in a conventional tractor, when mounting a front implement having a hydraulic motor and a hydraulic cylinder and performing complex work with the front and rear implements, the hydraulic actuator equipped on the implement is attached to the vehicle body. An auxiliary control valve mounted on the rear is connected via a hydraulic hose to drive a hydraulic actuator mounted on the implement.
For this reason, a hydraulic hose must be provided from the auxiliary control valve provided at the rear of the vehicle body to the front equipment, and a front equipment equipped with a hydraulic motor and a hydraulic cylinder is attached to the front of the car body, It was not possible to easily cope with the combined work using the front and rear implements by mounting the rear implements on the rear part of the vehicle body so that they could be raised and lowered.

  In view of the above-described problems, the present invention is configured such that a front implement including a hydraulic motor and a hydraulic cylinder is attached to the front portion of the vehicle body, and the rear implementation implement is movable up and down to the rear portion of the vehicle body. It is an object of the present invention to provide a tractor that can easily cope with complex work using a mentament.

The technical means taken by the present invention in order to solve the technical problem include: an auxiliary control valve for controlling a hydraulic actuator mounted on an implement attached to the vehicle body at a rear portion of the vehicle body; and a vehicle rear portion of the vehicle body. A raising / lowering control valve for controlling a hydraulic cylinder for a rear-implement that raises and lowers a rear-implement to be mounted;
A first control valve for operating a hydraulic motor mounted on a front implement mounted on the front of the vehicle body and a hydraulic cylinder mounted on the front implement on a front portion of the vehicle body. Provided with a valve unit for front imprint having two control valves,
The lifting control valve and the first and second control valves of the front impulsion valve unit are configured to be operated separately by pressure oil discharged from one hydraulic pump mounted on the vehicle body. Features.

In addition, the front impeller valve unit secures pressure oil discharged from the hydraulic pump and supplied to the first control valve and the second control valve of the front impeller valve unit, It is preferable to have a flow control valve for diverting the discharge oil of the hydraulic pump so as to supply the remainder of the pressure oil discharged from the hydraulic pump to the auxiliary control valve and the lift control valve.
Well, in addition to the flow control valve, the front impeller valve unit secures the pressure oil that flows out from the flow control valve and is supplied to the first control valve, and then from the flow control valve. It is preferable to have another flow control valve for diverting the pressure oil flowing out from the flow control valve to supply the remaining pressure oil flowing out to the second control valve.

  In addition, the front impeller valve unit is disposed on the side of the vehicle body, and the hydraulic pump discharge oil is disposed on the outer side in the left-right direction of the flow control valve that supplies the lift control valve and the other flow control valve. 2 control valve is located, the other flow control valve is located on the laterally outward side of the second control valve, and the first control valve is located on the laterally outward side of the other flow control valve. These flow control valves and the first and second control valves are preferably arranged side by side in the left-right direction so as to be directly connected.

  According to the present invention, when a front implement including a hydraulic motor and a hydraulic cylinder is attached to the front portion of the vehicle body and the rear implement is attached to the rear portion of the vehicle so as to be movable up and down, the front implement is equipped. The hydraulic hoses and hydraulic cylinders may be provided with hydraulic hoses from the first control valve and the second control valve of the front impeller valve unit provided at the front of the vehicle body. Can be facilitated, and the operation of the front implement and the lifting operation of the rear implement can be performed at the same time, so that it is possible to easily cope with the combined work using the front and rear implements.

It is the whole tractor side view. It is a hydraulic circuit diagram. It is a side view of the front part of a tractor. It is a front view of a valve unit. It is a top view of a valve unit. It is a side view of a 1st control valve. It is a side view of a flow control valve and a 2nd control valve. It is a side view of a hydraulic block. It is sectional drawing and the side view of the operation system of a 1st control valve. It is a side view of the operation system of a 2nd control valve. It is a front view of the operation system of a 2nd control valve.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a tractor. The tractor 1 is mainly composed of an engine 2, a flywheel housing 3 connected to the rear part of the engine 2, and a transmission case 4 connected to the rear part of the flywheel housing 3. A two-shaft, four-wheel tractor 1 that includes a vehicle body 5 that is supported by a pair of left and right front and rear wheels 6 and 7.
The transmission case 4 constituting a part of the vehicle body 5 includes a traveling system power transmission mechanism that transmits power from the engine 2 to the left and right rear wheels 7 via a clutch, a transmission, a rear wheel differential, and the like. 2 and a PTO power transmission mechanism for transmitting power from the rear surface of the vehicle body 5 to the PTO shaft 8 is housed. It is divided into a part case 4A (transmission case) and a rear case 4B (rear wheel differential case) housing a rear wheel differential gear.

A driver's seat 9 is provided at the rear of the vehicle body 5, and a steering handle 10 for steering the steered wheels (front wheels 6) is provided in front of the driver's seat 9.
In addition, a three-point link mechanism 13 (working machine mounting mechanism) including a top link 11 on the upper side and a pair of lower left and right lower links 12 is provided at the rear part of the vehicle body 5. The rear implement can be mounted on the rear portion of the vehicle body 5 through the vehicle.
Further, a work implement lifting device 14 for raising and lowering the rear implement is provided at the rear portion of the vehicle body 5. The work implement lifting device 14 includes a rear implement hydraulic cylinder 15 and a cylinder of the hydraulic cylinder 15. Each of the lift rods includes a pair of left and right lift arms 16 whose base side is supported by the case so as to be rotatable about a left and right axis, and a pair of left and right lift rods 17 whose upper ends are pivotally connected to the distal end side of the lift arm 16. The lower end side of 17 is pivotally connected to the middle part of the lower link 12 on the same side in the left-right direction.

The rear mounted hydraulic cylinder 15 is a single-acting hydraulic cylinder, and the lift arms 16 are configured such that the left and right lift arms 16 swing upward by projecting the piston rod of the rear mounted hydraulic cylinder 15. When the left and right lift arms 16 swing upward, the left and right lift rods 17 are pulled upward and the left and right lower links 12 swing upward, thereby raising the rear implement.
When lowering the rear implement, the rear implement is lowered by its own weight by removing the pressure oil from the rear implement hydraulic cylinder 15.

On the hydraulic cylinder 15, one or a plurality of (two in the present embodiment) auxiliary control valves for controlling a hydraulic actuator 18 mounted on an implement such as a rear-mounted implement mounted on the vehicle body 5 of the tractor 1. 19 is provided.
Further, at the rear part of the vehicle body 5 (on the lower surface side of the cylinder case of the rear-implement hydraulic cylinder 15 and at the upper part in the rear case 4B), an elevation control valve 20 for performing elevation control of the rear-implement hydraulic cylinder 15 is provided. Provided (see FIG. 2).
In the middle of the vehicle body 5 in the front-rear direction, hydraulic pressure that is driven by the power of a power transmission mechanism housed in the vehicle body 5, for example, PTO power transmission mechanism, and sends the lubricating oil in the transmission case 4 as hydraulic oil to hydraulic equipment. A pump P is provided.

The tractor 1 is provided with a lops 22 that is located on the front side of the steering handle 10 and that is formed in a U shape that is open downward and faces the rear part of the bonnet 21 that covers the engine 2. Left and right support members 23 that support the left and right lower ends of 22 are fixed to left and right support brackets 24 made of a plate material bolted to the side surface of the flywheel housing 3 or the like.
In addition, a front implement can be attached to the front portion of the vehicle body 5 via a working machine mounting mechanism (not shown), and on the front side of the vehicle body 5 (right side in the present embodiment) There is provided a front-implement-improvement valve unit 28 (hereinafter simply referred to as a valve unit) in which valves and the like for operating the hydraulic actuators 25 and 26 mounted on the front-end implement are integrated.

In this embodiment, as shown in FIGS. 2 to 8, the valve unit 28 includes one hydraulic block 29, two flow control valves 30, and one first control valve 31 (control valve for front impulsion). ) And two second control valves 32 (control valves for front impulsion).
The hydraulic block 29 is for introducing oil discharged from the hydraulic pump P into the valve unit 28 and returning oil returned from the hydraulic actuators 25 and 26 to the tank (transmission case 4).

The flow control valve 30 is for diverting the pressure oil from the hydraulic pump P.
The first control valve 31 is for operating the hydraulic motor 25 installed in the front implement, and the second control valve 32 is for operating mainly the hydraulic cylinder 26 installed in the front implement. For example, when a branch cutter that cuts branches in an orchard is used as the front implement, the first control valve 31 of the valve unit 28 is connected to a hydraulic motor 25 that rotationally drives the cutter, The second control valve 32 is connected to the hydraulic cylinder 26 for adjusting the vertical position of the cutter, and the other second control valve 32 is connected to the hydraulic cylinder 26 for adjusting the horizontal position of the cutter.

A plurality of first control valves 31 may be provided, and one or three or more second control valves 32 may be provided.
The hydraulic block 29, the flow control valve 30, the first control valve 31, and the second control valve 32 are arranged side by side in the left-right direction, and adjacent ones are overlapped and connected (directly connected) in the left-right direction. ing.
Specifically, the hydraulic block 29 is positioned on the inner end side in the left-right direction, and one flow control valve 30 (referred to as the first flow control valve 30A) is positioned on the outer side of the hydraulic block 29 in the left-right direction. One second control valve 32 is located on the outer side in the left-right direction of the first flow control valve 30A, and the other second control valve 32 is located on the outer side in the left-right direction of the one second control valve 32, The other flow control valve 30 (this is referred to as a second flow control valve 30B) is located on the outer side in the left-right direction of the other second control valve 32, and is located on the outer side in the left-right direction of the second flow control valve 30B. It arrange | positions so that the 1st control valve 31 may be located.

In addition, inward in the left-right direction refers to a direction from the side surface of the vehicle body 5 toward the center in the left-right direction, and outward in the left-right direction refers to a direction from the center in the left-right direction of the vehicle body 5 toward the side surface.
A valve stay 33 is bolted to the lower portion of the support bracket 24, and the hydraulic block 29 is attached and fixed to the valve stay 33, whereby the valve unit 28 is attached to the vehicle body 5.
When the lops 22 are not provided at the front portion of the tractor 1, the valve stay 33 is attached to the flywheel housing 3 or the like directly or via another bracket.

A protective cover 34 that covers the valve unit 28 from below is attached to the valve stay 33.
The hydraulic block 29 communicates with a discharge port of the hydraulic pump P through a discharge line a, and a pressure port from the hydraulic pump P communicates with the pump port 36 through a supply path b. A first out port 37 through which the oil flows out to the first flow control valve 30A, and first and second drain imports 38 through which the return pressure oil from the hydraulic actuators 25, 26 mounted on the front implement is introduced. 39, a tank port 40 communicating with the tank 4 via the drain line c, a first drain oil path d communicating the tank port 40 and the first drain import 38, and the first drain oil path d A second drain oil passage e communicating with the second drain import 39, and a relief oil having one end connected to the first drain oil passage d and the other end connected to the supply passage b f, a relief valve 41 interposed in the relief oil passage f, an import 42 into which the pressure oil from the first flow control valve 30A flows, and a second communicating with the import 42 via the communication passage g. An outport 43 is provided.

A connection pipe 44 constituting a part of the discharge pipe a is connected to the pump port 36 of the hydraulic block 29, and connection pipes 45 and 46 are also connected to the second out port 43 and the second drain import 39. Yes.
Further, a support plate 47 is provided on the other end side of the connection pipe 46 whose one end is connected to the second drain import 39, and this support plate is attached to a support stay 48 fixed to the valve stay 33.
The drain pipe c is constituted by a pipe having one end connected to the tank port 40 and the other end connected to the transmission case 4.

  The flow control valve 30 includes a main import 49 serving as a pressure oil inlet from the hydraulic pump P, first and second out ports 50 and 51 serving as a pressure oil outlet, and a flow of pressure oil return oil. A drain import 52 that serves as an inlet, a drain out port 53 that communicates with the drain import 52 via a drain oil passage h, a sub-import 54 that serves as a pressure oil inlet, and pressure oil that has flowed in from the main import 49 A priority valve 55 for branching into a first path i flowing to the first outport 50 and a second path j flowing to the second outport 51, a variable throttle 56 provided in the first path i, and the sub-import 54 is connected to the second path j, and a check valve 57 is provided in the combined path k to prevent backflow of pressure oil from the second path j to the sub-import 54. It is.

In this flow control valve 30, when the variable throttle 56 is fully opened, the total flow rate of the pressure oil flowing from the main import 49 flows to the first path i through the priority valve 55 and flows out from the first out port. By restricting the variable throttle 56, the required flow rate of the pressure oil flowing in from the main import 49 flows to the first path i through the priority valve 55 and flows out from the first out port 50 preferentially, and the remaining pressure. The oil is configured to flow into the second path j through the priority valve 55 and out of the second out port 51.
When the variable throttle 56 is fully closed, the total flow rate of the pressure oil flowing from the main import 49 flows out from the second outport 51.

The variable throttle 56 can be throttled by an operating handle 58 provided on the top of each flow control valve 30.
The main import 49 of the first flow control valve 30A is in communication with the first out port 37 of the hydraulic block 29, and the second out port 51 of the first flow control valve 30A is connected to the import 42 of the hydraulic block 29. Communicate.
Further, the pressure oil flowing out from the first out port 50 of the first flow control valve 30A is supplied to the first control valve 31 and the second control valve 32, and the pressure flowing out from the second out port 43 of the hydraulic block 29. The oil is configured to be supplied to the auxiliary control valve 19 and the elevation control valve 20.

Therefore, the first flow control valve 30A secures the pressure oil that is discharged from the hydraulic pump P and supplied to the control valves 31 and 32 that operate the hydraulic actuators 25 and 26 installed in the front implement. The hydraulic oil discharged from the hydraulic pump P can be divided in order to supply the remaining pressure oil discharged from the hydraulic pump P to the auxiliary control valve 19 and the lift control valve 20.
The drain out port 53 of the first flow control valve 30A communicates with the first drain import 38 of the hydraulic block 29.

The first control valve 31 is interposed in an import 59 for allowing pressure oil to flow in, an outport 60 for allowing pressure oil to flow out to the hydraulic motor 25, and a communication path m that connects the import 59 and the outport 60. And a switching valve 61.
The switching valve 61 includes an opening position 61a for opening the communication path m to supply pressure oil to the hydraulic motor 25 installed in the front implement, and a shut-off position for stopping supply of pressure oil to the hydraulic motor 25. It consists of a rotary spool type 2-port 2-position switching valve that can be switched to 61b.
The hydraulic hose for guiding the return oil from the hydraulic motor 25 is connected to a connection pipe 46 connected to the second drain import 39 of the hydraulic block 29, and the return oil from the hydraulic motor 25 passes through the hydraulic block 29. Through the tank 4.

The import 59 of the first control valve 31 communicates with the first out port 50 of the second flow control valve 30B.
Note that the drain import 52 and the sub-import 54 of the second flow control valve 30B are closed.
The second control valve 32 includes first and second imports 62 and 63 that are pressure oil inflow ports, a first out port 64 that communicates with the first import 62 via a communication path n, and a second import 63 when neutral. A second outport 65 communicating with the drain, a drain import 66 serving as a return pressure oil inlet, a drain out port 67 communicating with the drain import 66 via a drain oil passage o, and a front implement A pair of pressure oil supply / discharge ports 68 for supplying and discharging pressure oil to / from the hydraulic cylinder 26 (or other hydraulic actuator), and a hydraulic cylinder 25 (or other hydraulic equipment) equipped in the front implement The direction switching valve 69 for switching the direction of the flow of pressure oil to the hydraulic actuator), and the flow of pressure oil between the direction switching valve 69 and one pressure oil supply / discharge port 68 And a lock valve 70 interposed.

The direction switching valve 69 is a linear spool type 8-port 3-position switching valve that can be switched to a neutral position 69a, a first switching position 69b, and a second switching position 69c. The second outport 65 is communicated, and the flow of pressure oil from the second import 63 to the second outport 65 is blocked at the first and second switching positions 69b and 69c.
When the second control valve 32 is connected to the hydraulic cylinder 26, no pressure oil is supplied to or discharged from the hydraulic cylinder 26 at the neutral position 69a, and the piston rod of the hydraulic cylinder 26 at the first switching position 69b. The piston rod of the hydraulic cylinder 26 is retracted at the second switching position 69c.

The lock valve 70 allows the flow of pressure oil between the direction switching valve 69 and the pressure oil supply / discharge port 68 when the direction switching valve 69 is in the first and second switching positions 69b and 69c. Is in the neutral position 69a, the flow of the pressure oil between the direction switching valve 69 and the pressure oil supply / discharge port 68 is interrupted, and the hydraulic cylinder 26 is stopped and held.
In the present embodiment, the lock valve 70 is interposed in the pressure oil flow passage between the pressure oil supply / discharge port 68 and the direction switching valve 69 communicated with the bottom side oil chamber of the hydraulic cylinder 26.
The first import 62 of the second control valve 32 adjacent to the first flow control valve 30A communicates with the first outport 50 of the first flow control valve 30A, and the second outport of the second control valve 32. 65 communicates with the sub-import 54 of the first flow control valve 30A, and the drain out port 67 of the second control valve 32 communicates with the drain import 52 of the first flow control valve 30A.

Further, the first import 62 of the second control valve 32 on the inner side in the left-right direction communicates with the first out port 64 of the second control valve 32 on the outer side in the left-right direction, and the second control valve 32 on the inner side. The second outport 65 communicates with the second import 63 of the second control valve 32 on the outer side, and the drain outport 67 of the second control valve 32 on the inner side controls the second control valve on the outer side. The valve 32 communicates with a drain import 66.
The main import 49 of the second flow control valve 30B communicates with the first outport 64 of the second control valve 32 adjacent to the second flow control valve 30B, and the second import of the second control valve 32 63 communicates with the second out port 51 of the second flow control valve 30B, and the drain import 66 of the second control valve 32 communicates with the drain out port 53 of the second flow control valve 30B.

  The pressure oil flowing out from the first out port 50 of the first flow control valve 30A flows into the second flow control valve 30B from the main import 49 through the two second control valves 32, and this second flow. The pressure oil flowing into the control valve 30B flows to the first path i through the priority valve 55 through the priority valve 55, flows out of the first out port 50 preferentially, and is sent to the first control valve 31, while remaining. The pressure oil flows to the second path j through the priority valve 55, flows out from the second out port 51, and is sent to the second control valve 32.

Therefore, the second flow control valve 30B flows out of the first flow control valve 30A after securing the pressure oil flowing out of the first flow control valve 30A and supplied to the first control valve 31. The pressure oil flowing out from the first flow control valve 30A can be divided so that the remaining pressure oil is supplied to the second control valve 32.
Further, when the switching valve 61 of the first control valve 31 is switched to the cutoff position 61b (when the first control valve 31 does not supply pressure oil to the hydraulic motor 25), the second The entire flow rate of the pressure oil flowing into the flow control valve 30B is configured to flow to the second control valve 32.

Further, the pressure oil that has passed through the second control valve 32 flows into the first flow control valve 30A from the sub-import 54, and joins the second path j of the first flow control valve 30A via the combined flow path k.
The pressure oil flowing out from the second out port 43 of the hydraulic block 29 is supplied to the auxiliary control valve 19 through the hydraulic line q.
The auxiliary control valve 19 is configured in substantially the same manner as the second control valve 32 of the valve unit 28, and an implement hydraulic actuator mounted on the vehicle body 5 can be controlled by the auxiliary control valve 19.

The two second control valves 32 of the valve unit 28 constitute a dandem circuit, whereas the two auxiliary control valves 19 constitute a parallel circuit.
The pressure oil flowing out from the second out port 43 of the hydraulic block 29 of the valve unit 28 passes through the valve bodies of the two auxiliary control valves 19 and is sent to the flow priority valve 71, and is constant by the flow priority valve 71. The amount is sent to the direction switching valve 69 of the auxiliary control valve 19 and excess oil is drained to the tank 4.

The pressure oil that has passed through the direction switching valve 69 of the auxiliary control valve 19 is sent to the elevation control valve 20 that controls the hydraulic cylinder 15 for the rear installation.
The lift control valve 20 will be described together with its operation. When the spool 72 of the lift control valve 20 is in the neutral position 72a, the pressure oil from the valve unit 28 (hydraulic pump P) pushes the unload valve 73 open to open a transmission case. Returning to step 4, the oil in the hydraulic cylinder 15 for the rear-implement is not drained because the drain valve 74 is closed, and the rear-implement is held at a constant height.

When the spool 72 of the elevation control valve 20 is switched from the neutral position 72a to the raised position 72b by operating means such as an operating lever, the oil discharge valve 74 remains closed and the pressure oil from the valve unit 28 is unloaded. Since the unloading valve 73 is closed by acting on the rear surface of 73, the pressure oil from the valve unit 28 pushes open the check valve 76 of the descending speed control valve 75 and flows into the hydraulic cylinder 15 for rear-implement. As a result, the piston rod of the hydraulic cylinder 15 for rear-mounted impling protrudes and the lift arm 16 swings upward.
Further, when the operating means switches the spool 72 of the elevation control valve 20 from the neutral position 72a to the lowered position 72c, the oil discharge valve 74 is moved via the interlocking means to open the oil discharge valve 74, and the hydraulic pressure for the rear impulse The oil in the cylinder 15 is pushed out by the weight of the rear implement, and returns from the oil discharge valve 74 into the transmission case 4 so that the rear implement is lowered. At this time, the pressure oil from the valve unit 28 pushes open the unload valve 73 and returns into the transmission case 4.

Reference numeral 77 denotes a safety valve for the hydraulic cylinder 15 for the rear impeller.
In the tractor 1 having the above-described configuration, the control valves 31 and 32 (the front valve) are operated by the first flow control valve 30A to operate the hydraulic actuators 25 and 26 that are discharged from the hydraulic pump P and installed in the front load implement. The hydraulic pump is configured so that the remaining pressure oil discharged from the hydraulic pump P can be supplied to the auxiliary control valve 19 and the lift control valve 20 after securing the pressure oil supplied to the control valve for impulsion). Since the discharge oil of P can be divided, it is possible to drive the hydraulic actuators 25 and 26 provided in the front implement and to raise and lower the rear implement at the same time.

Therefore, for example, the above-described branch cutter is used as the front implement, and the sweeper or the cut branch that is cut into the storage portion by the rotating brush is used to crush the branch cut by the branch cutter as the rear implement. In the case of using a chopper that is stored in the storage unit and performing a complex operation, when the tractor 1 is turned during the operation, the sweeper or the chopper can be moved up and down while rotating the cutter unit of the branch cutter. , Work efficiency can be improved.
In the vicinity of the steering handle 10, one first operation lever 77 for operating the first control valve 31 and two second operation levers 78 for operating the second control valve 32 are provided. .

The operation levers 77 and 78 are disposed on the right side of the steering handle 10 in the present embodiment.
As shown in FIG. 9, the first operating lever 77 is supported by a support bracket 79 attached to a steering support that supports the steering handle 10 so as to be rotatable about the left and right axes, and can be swung up and down. Yes.
A locking piece 80 bent toward the inner side in the left-right direction is provided on the rear end side of the support bracket 79, and a locking groove 81 for positioning the first operation lever 77 is provided on the locking piece 80. A pair of upper and lower sides are formed.

The first operating lever 77 can be moved in the left-right direction. The first operating lever 77 is disengaged from the locking groove 81 by moving inward in the left-right direction from the position engaged with the locking groove 81 and is locked by the biasing force of the return spring 82. It is configured to be held in a state of being engaged with the groove 81.
The first control valve 31 of the valve unit 28 is constituted by a rotary valve. An operation arm 83 connected to the spool of the first control valve 31 and the first operation lever 77 are connected to a Bowden cable 84 (or a link mechanism or the like). Are linked via a link means).

The operation arm 83 of the first control valve 31 is provided on the outer surface side of the valve body of the first control valve 31 so as to be swingable up and down, and is biased in a direction to be pulled down by a return spring 85.
One end side of the outer cable 84 a of the Bowden cable 84 is attached to an outer receiving stay 86 fixed to the support bracket 79, and the other end side of the outer cable 84 a is the left and right outer surface side of the valve body of the first control valve 31. It is attached to the outer receiving stay 87 fixed to.

One end side of the inner cable 84 b of the Bowden cable 84 is connected to a swing arm 88 that swings integrally with the first operation lever 77, and the other end side of the inner cable 84 b is connected to the operation arm 83 of the first control valve 31. It is connected.
In the present embodiment, the switching valve 61 of the first control valve 31 is set to the cutoff position 61b in a state where the first operating lever 77 is engaged with the lower locking groove 81. From this state, the first operating lever 77 By pulling up, the switching valve 61 of the first control valve 31 is switched to the open position 61a.

The second operation lever 78 is juxtaposed in the left-right direction, can operate the second control valve 32 on the same side in the left-right direction, and is attached to a support bracket 89 attached to the transmission case 4.
As shown in FIGS. 10 and 11, the support bracket 89 includes a mounting plate 90 that is bolted to the right side surface of the upper part of the front end side of the transmission case 4, a support 91 that is fixed to the mounting plate 90 at its lower end side, The support 91 includes a support stay 92 fixed to the upper end of the support 91.

The support 91 is made of a pipe material, and is bent in an L shape so as to extend in an inclined direction that moves backward as it goes upward after being extended outward from the mounting plate 90 in the left-right direction.
The support stay 92 is formed in a U shape from a bottom wall 92a fixed to the upper end of the support 91 and left and right side walls 92b extending upward from the left and right sides of the bottom wall 92a.
A support shaft 93 having a horizontal axis is provided over the left and right side walls 92b of the support stay 92, and a cylindrical boss 94 provided at the base of each second operating lever 78 is provided on the support shaft 93 in the horizontal direction. The second operation lever 78 is pivotably fitted back and forth, and is fitted around the shaft so as to be rotatable.

An interlocking arm 95 is fixed to the boss 94 of each second operating lever 78 in an extending shape on the front side, and each second control valve 32 is provided with an operating arm 96 for operating the spool of the direction switching valve 69. The interlocking arm 95 and the operating arm 96 are interlocked via a Bowden cable 97 (or interlocking means such as a link mechanism), and the direction switching valve 69 of the second control valve 32 is operated by swinging the second operating lever 78 back and forth. Are configured to be switched.
The operation arm 96 provided in the second control valve 32 is disposed below the second control valve 32, and the front end side is pivotally attached to the second control valve 32 so as to be rotatable around the left and right axes, and the rear end. One end side of the inner cable 97a of the Bowden cable 97 is pivotally connected to the side, and the midway portion is linked to the spool of the direction switching valve 69 of the second control valve 32.

Further, an outer receiving stay 98 to which an outer cable 97 b on one end side of the Bowden cable 97 is attached is fixedly attached to the back surface of the second control valve 32.
The other end side of the inner cable 97a of the Bowden cable 97 is connected to the front end side of the interlocking arm 95, and the other end side of the outer cable 97b of the Bowden cable 97 is a midway in the vertical direction of the support 91 of the support bracket. It is attached and fixed to the outer receiving stay 99 fixed to the frame.
The support bracket 89 that supports the second operation lever 78 is provided with a protective cover 100 that covers the upper surface side, the front surface side, and the outer surface of the other end side of the interlocking arm 95 and the Bowden cable 97.

DESCRIPTION OF SYMBOLS 5 Car body 15 Hydraulic cylinder for rear impulsation 18 Hydraulic actuator 19 Auxiliary control valve 20 Lift control valve 25 Hydraulic motor 26 Hydraulic cylinder 28 Valve unit for front imple 30A Flow control valve 30B Flow control valve 31 1st control valve 32 2nd control Valve P Hydraulic pump

Claims (4)

An auxiliary control valve (19) for controlling a hydraulic actuator (18) mounted on an implement mounted on the vehicle body (5) and a rear mounted on the rear portion of the vehicle body (5) An elevating control valve (20) for controlling a hydraulic cylinder (15) for rear installation that raises and lowers the installation implement,
A first control valve (31) for operating a hydraulic motor (25) mounted on a front implement mounted on the front of the vehicle body (5), and the front implement on the front of the vehicle body (5) A valve unit (28) for front impeller having a second control valve (32) for operating a hydraulic cylinder (26) mounted on the attachment,
The raising / lowering control valve (20) and the first and second control valves (31, 32) of the front-implement valve unit (28) are connected to one hydraulic pump (P) mounted on the vehicle body (5). A tractor characterized in that the tractor is configured to be operated separately depending on the pressure oil discharged.   The front impeller valve unit (28) is discharged from the hydraulic pump (P) to the first control valve (31) and the second control valve (32) of the front impeller valve unit (28). After securing the supplied pressure oil, the hydraulic pump (P) is supplied to supply the remaining pressure oil discharged from the hydraulic pump (P) to the auxiliary control valve (19) and the elevation control valve (20). The tractor according to claim 1, further comprising a flow control valve (30A) for diverting the discharged oil of P).   In addition to the flow control valve (30A), the front impeller valve unit (28) ensures pressure oil that flows out of the flow control valve (30A) and is supplied to the first control valve (31). Then, another flow for diverting the pressure oil flowing out from the flow control valve (30A) to supply the remaining pressure oil flowing out from the flow control valve (30A) to the second control valve (32). The tractor according to claim 2, comprising a control valve (30B).   The front impeller valve unit (28) is disposed on the side of the vehicle body (5), and the oil discharged from the hydraulic pump (P) is supplied to the lift control valve (20) and the other flow control valve (30B). A second control valve (32) is positioned on the laterally outward side of the flow control valve (30A) to be supplied, and the other flow control valve (30B) is disposed laterally outward of the second control valve (32). ) And the flow control valve (30A, 30B) and the first and second control valves so that the first control valve (31) is located on the outer side in the left-right direction of the other flow control valve (30B). The tractor according to claim 3, wherein (31, 32) are arranged in a line in the left-right direction and directly connected.

Images