JP2005295870A - Circuit for taking out hydraulic pressure for implement from tractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To replace a second direction changeover valve for changing over a driving state of an implement driving actuator for driving the implement for a tractor with a simple and inexpensive valve and to reduce the cost of a circuit for taking out the hydraulic pressure for the implement in which the second direction changeover valve is integrated in the circuit for taking out the hydraulic pressure for the implement for driving the implement for the tractor. <P>SOLUTION: First supply and exhaust passages 34 and 35 for connecting a first direction changeover valve 18 to a horizontal control cylinder 3 for a three-point supporting apparatus are arranged in series relatively to the first direction changeover valve 18 with the second direction changeover valve 32. Furthermore, the second direction changeover valve 32 is connected through second supply and exhaust passages 36 and 37 to a lifting arm driving cylinder 8 and the changeover operation of forward and return movements of the lifting arm driving cylinder 8 is performed with the first direction changeover valve 18. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydraulic circuit for operating a hydraulic actuator such as a hydraulic cylinder that drives and operates a tractor work machine attached to a tractor.

  The tractor 1 mainly used for agricultural work, cargo handling, and transport work is used in a state where a tractor rear working machine such as a tiller 2 is attached to the rear side as shown in FIG. A tractor rear working machine such as a tiller 2 is not tilted in the vehicle width direction by a three-point support device horizontal control cylinder 3 that drives a link (hereinafter referred to as a three-point support device) for attaching the tractor rear work machine. While being driven and controlled, the three-point support device lift cylinder 4 is driven up and down. (For example, refer to Patent Document 1).

  Moreover, the tractor 1 is used in a state where a tractor working machine such as a loader 5 is attached to the front side thereof as shown in FIG. The loader 5 includes a lift arm 6 and a loader attachment 7 such as a bucket. The lift arm 6 is driven and operated by a lift arm drive cylinder 8, and the loader attachment 7 such as a bucket is driven by a loader attachment drive cylinder 9 ( For example, see Patent Document 2). When the loader is mounted on the front surface side, as shown in FIG. 18, the weight balance in the vehicle front-rear direction is adjusted by attaching the weight 10 on the rear surface side or attaching the tiller 2 described above.

  The work machine drive actuators such as the lift arm drive cylinder 8 and the loader attachment drive cylinder 9 include a three-point support device such as a three-point support device horizontal control cylinder 3 and a three-point support device lift cylinder 4 as shown in FIG. It is incorporated into a hydraulic pressure take-out circuit for a work machine having a drive cylinder and is driven.

  The work machine hydraulic pressure take-out circuit 11 includes a hydraulic pressure supply source 15 including a prime mover 12, a hydraulic pump 13, and an oil tank 14, and an adjustment unit 16 that adjusts the pressure and flow rate of the pressure oil sent from the hydraulic pressure supply source 15. A first direction switching valve 18 (three-position two-solenoid type in this illustrated example), a first direction switching valve 18 and supply / discharge passages 19a, 19b connected to the adjusting unit 16 via the supply / discharge passages 17a, 17b. The three-point support device horizontal control cylinder 3 connected via the pressure supply system forms a pressure oil supply / discharge system from the hydraulic supply source 15 to the three-point support device horizontal control cylinder 3.

  Further, a second direction switching valve 21 (three-position two-solenoid type in this illustrated example) is connected to the hydraulic pressure supply source 15 via supply / discharge passages 20 a and 20 b, and the lift arm drive cylinder 8 is connected to the second direction switching valve 21. By connecting through the supply / discharge passages 22a and 22b, a supply / discharge system from the hydraulic supply source 15 to the lift arm drive cylinder 8 is formed.

  Further, by connecting the three-point support device lift cylinder 4 to the hydraulic supply source 15 via the direction switching unit 23, a supply / discharge system from the hydraulic supply source 15 to the three-point support device lift cylinder 4 is formed. In FIG. 19, 24 is a relief valve, 25 is a flow priority valve, 26 is a check valve, 27 is a pilot check valve, and 28 is a slow return valve.

  Of these, the first direction switching valve 18 and the second direction switching valve 21 are independent of each other by, for example, a three-point support device operation switch 29 (see FIG. 17) or a loader operation lever 30 (see FIG. 18) provided in the driver's seat. Controlled. First, when the three-point support device operation switch 29 and the loader operation lever 30 are in the neutral position (not tilted), the first direction switching valve 18 and the second direction switching valve 21 are as shown in FIG. They are in neutral positions A0 and A0, respectively, so that pressure oil is not supplied to or discharged from the three-point support device horizontal control cylinder 3 and the lift arm drive cylinder 8.

  When the three-point support device operation switch 29 is operated to switch the first direction switching valve 18 to the position A1, the pressure oil sent from the hydraulic supply source 15 through the adjusting unit 16 is supplied and discharged as shown in FIG. The oil is supplied to the oil chamber 3a of the three-point support device horizontal control cylinder 3 through the passage 17a, the first direction switching valve 18, and the supply / discharge passage 19a. At the same time, the pressure oil discharged from the oil chamber 3b is drained to the oil tank 14 through the supply / discharge passage 19b, the first direction switching valve 18, and the supply / discharge passage 17b, so that the piston 3c is pushed toward the oil chamber 3b. The piston rod 3d retracts. On the other hand, when the first direction switching valve 18 is switched to the position A2, as shown in FIG. 21, the pressure oil sent from the hydraulic supply source 15 via the adjusting unit 16 is supplied to the supply / discharge passage 17a, the first direction. The oil is supplied to the oil chamber 3b of the three-point support device horizontal control cylinder 3 through the switching valve 18 and the supply / discharge passage 19b. At the same time, the pressure oil discharged from the oil chamber 3a is drained to the oil tank 14 through the supply / discharge passage 19a, the first direction switching valve 18, and the supply / discharge passage 17b, so that the piston 3c is pushed toward the oil chamber 3a. The piston rod 3d extends. In this way, the three-point support device horizontal control cylinder 3 expands and contracts, and the tiller 2 is horizontally controlled.

Further, in the state where the loader operation lever 30 is operated and the second direction switching valve 21 is switched to the position A1, the pressure oil sent from the hydraulic supply source 15 is not shown, but the three-point support device horizontal control cylinder 3 is followed by the same supply / discharge route as in the case of supplying / discharging pressure oil. That is, the pressure oil sent from the hydraulic pressure supply source 15 is supplied to the oil chamber 8a of the lift arm drive cylinder 8 through the supply / discharge passage 20a, the second direction switching valve 21, and the supply / discharge passage 22a. Pushed toward the oil chamber 8b, the piston rod 8d retracts. On the other hand, in the state where the second direction switching valve 21 is switched to the position A2, the pressure oil delivered from the hydraulic pressure supply source 15 is omitted from the illustration, but the supply / discharge passage 20a and the second direction switching valve are also omitted. 21, since the oil is supplied to the oil chamber 8b of the lift arm drive cylinder 8 through the supply / discharge passage 22b, the piston 8c is pushed toward the oil chamber 8a, and the piston rod 8d extends. As a result, the lift arm drive cylinder 8 expands and contracts, and the lift arm 6 of the loader 5 moves up and down.
JP 7-143802 A JP-A-8-226138

  As described above, the three-point support device drive cylinder such as the three-point support device horizontal control cylinder 3 and the work machine drive actuator such as the lift arm drive cylinder 8 have independent supply / discharge systems, and each drive actuator A double-acting cylinder is mainly used for driving. Therefore, both the first directional switching valve 18 and the second directional switching valve 21 require a three-position type expensive directional switching valve, which increases the cost of the working machine hydraulic pressure take-out circuit 11.

  In order to solve the above-mentioned problems, a hydraulic extraction circuit for a work machine from a tractor according to the present invention includes a hydraulic supply source having a hydraulic pump, and a three-point support device connected to the hydraulic supply source and attached to the rear surface side of the tractor. The three-point support device drive cylinder is driven, and the three-point support device drive cylinder is moved forward, backward, or stopped to the first oil supply / discharge passage connecting the hydraulic supply source and the three-point support device drive cylinder. A tractor equipped with a tractor work machine attached to a tractor having a first directional switching valve for switching to a tractor, and for extracting the work machine hydraulic pressure for operating the work machine drive actuator for driving the tractor work machine from the tractor side When the second direction switching valve is interposed in the first supply / discharge passage between the first direction switching valve and the three-point support device drive cylinder in the hydraulic pressure take-out circuit for the work machine from In addition, the second direction switching valve and the work machine drive actuator are connected via the second supply / discharge passage, and the supply / discharge from the first direction switching valve to the three-point support device driving cylinder is performed by selecting the second direction switching valve. The system can be switched to a supply / discharge system from the first direction switching valve to the work machine drive actuator.

  Tractor rear working machines such as tillage machines attached to the rear side of the tractor via a three-point support device are mainly used for agricultural work, and work for tractors such as a loader attached to the front side of the tractor. Since the machine is mainly used for cargo handling and transportation work, it is not necessary to operate both at the same time. Therefore, the first direction switching valve that switches the three-point support device drive cylinder to any one of the forward, backward, and stopped states and the work machine drive actuator to any one of the forward, backward, and stopped states. Of the second direction switching valves to be switched, when one valve is being switched, the other valve is not switched. The present invention has been devised by paying attention to the fact that the first directional switching valve and the second directional switching valve are not switched at the same time. A part of the first direction switching valve is provided. That is, according to the present invention, the on / off switching operation of supplying and discharging the pressure oil to and from the work machine drive actuator and the switching operation of the drive direction of the work machine drive actuator, which have been conventionally performed by the second direction switching valve, are switched to the first direction switching valve. It is something that is done by. Therefore, the second direction switching valve only needs to have a function of switching the pressure oil supply / discharge system to the three-point support device drive cylinder and the hydraulic oil supply / discharge system to the work machine drive actuator by a selection operation. As a result, the second direction switching valve can be replaced with a simple one.

  Further, the present invention provides a supply / discharge system from the hydraulic supply source to the work machine drive actuator by interposing a second direction switching valve in the first supply / discharge passage between the first direction switching valve and the three-point support device drive cylinder. Since a part is shared with the supply / discharge system from the hydraulic supply source to the three-point support device drive cylinder, piping can be simplified, and the hydraulic take-out circuit for the working machine can be made compact.

  The present invention can also be applied to a case where a plurality of work implement drive actuators are provided. In that case, one or a plurality of second direction switching valves are provided, and a plurality of work implement drive actuators and one or a plurality of second actuators are provided. Directional switching valves are connected continuously, and one or more second direction switching valves are selected to select the supply / discharge system from the hydraulic supply source to each work machine drive actuator including the three-point support device drive cylinder. It is only necessary to adopt a configuration that allows selection.

  As the tractor work machine, for example, a loader can be used, and it is mainly used by being attached to the front side of the tractor. In this case, two work implement drive actuators and two second direction switching valves are provided. For example, a loader lift cylinder that drives a lift arm of a loader and a loader attachment drive cylinder that drives a loader attachment are provided as work implement drive actuators, and one second direction switching valve is provided via one second supply / discharge passage. A loader lift cylinder is connected, and another second direction switching valve is interposed in one second supply / discharge passage between the one second direction switching valve and the loader lift cylinder, and the other second direction switching valve The loader attachment drive cylinder is connected through another second supply / discharge passage, and the supply / discharge system from one second direction switching valve to the loader lift cylinder is connected to one second by selecting another second direction switching valve. It is also possible to switch to a supply / discharge system from the direction switching valve to the loader attachment drive cylinder.

  In addition, for example, a boom type mower can be used as the tractor working machine, and the boom type mower is used by being attached to the front side or the rear side of the tractor.

  As described above, according to the hydraulic pressure extracting circuit for work implements from the tractor according to the present invention, the switching operation of the driving direction of the work implement driving actuator is performed by the first direction switching valve. Can be replaced with a simple and inexpensive one. As a result, it is possible to reduce the cost of the work machine hydraulic pressure takeout circuit.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected and demonstrated to the thing which show | plays the same effect | action as the member and site | part mentioned above.

  FIG. 1 shows a working machine hydraulic pressure extraction circuit 31 from a tractor according to a first embodiment of the present invention. This work machine hydraulic pressure take-out circuit 31 mainly includes a hydraulic pressure supply source 15, a first direction switching valve 18, a second direction switching valve 32, a three-point support device drive cylinder 33A, and a work machine drive actuator 33B. ing. The three-point support device drive cylinder 33A is a three-point support device attached to the rear surface side of the tractor 1 (see FIGS. 17 and 18), and the work implement drive actuator 33B is the other surface side of the tractor 1 (this figure). In the example shown, the tractor work machine attached to the front side is driven and operated.

  The tractor rear working machine is a tiller 2 in this embodiment, and is attached to the rear side of the tractor 1 via, for example, a three-point support device. Moreover, the working machine for tractors is the loader 5 in this embodiment, and is used by being attached to the front side of the tractor 1, for example.

  In this embodiment, the three-point support device drive cylinder 33A is composed of a double-acting three-point support device horizontal control cylinder 3 for driving the three-point support device and a single-action three-point support device lift cylinder 4. Of these, the three-point support device horizontal control cylinder 3 is connected to the hydraulic pressure supply source 15 via the first supply / discharge passages 34 and 35.

  The first direction switching valve 18 is interposed in the first supply / discharge passages 34, 35 between the hydraulic supply source 15 and the three-point support device horizontal control cylinder 3. In this embodiment, the first direction switching valve 18 is a four-port three-position two-solenoid type direction switching valve. The first direction switching valve 18 is connected to the two ports provided on the hydraulic pressure supply source 15 side via the first supply / discharge passages 34a and 35a. A hydraulic supply source 15 is connected.

  The second direction switching valve 32 is interposed in the first supply / discharge passages 34, 35 between the first direction switching valve 18 and the three-point support device horizontal control cylinder 3. In this embodiment, the work machine drive actuator 33B is a double-acting lift arm drive cylinder 8, and the lift arm drive cylinder 8 and the second direction switching valve 32 pass through the second supply / discharge passages 36 and 37. Connected through.

  In this embodiment, the second direction switching valve 32 is a 6-port 2-position 1 solenoid type direction switching valve. Two ports provided on the first direction switching valve 18 side are connected to the first supply / discharge passages 34b and 35b. The first direction switching valve 18 is connected to two ports provided on the three-point support device horizontal control cylinder 3 side. Of the remaining four ports, two ports provided on the three-point support device horizontal control cylinder 3 side are connected to the oil chambers 3a and 3b of the three-point support device horizontal control cylinder 3 via the first supply / discharge passages 34c and 35c. The two ports provided on the lift arm drive cylinder 8 side are connected to the oil chambers 8a and 8b of the lift arm drive cylinder 8 via the second supply / discharge passages 36 and 37, respectively.

  Although the illustration of the first direction switching valve 18 is omitted when the solenoids SL1 and SL2 are not excited, the spool disposed in the first direction switching valve 18 is brought into the neutral position A0 by the elastic restoring force of the spring. Retained. In this state, the first supply / discharge passage 34a and the first supply / discharge passage 35a communicate with each other, while the first supply / discharge passages 34b and 35b are shut. In the state where the solenoid SL1 is excited and the spool is moved toward the solenoid SL2 (position A1), the first supply / discharge passage 34a and the first supply / discharge passage 34b are connected to the first supply / discharge passage 35a and the first supply / discharge passage 35a. In a state where the supply / discharge passage 35b communicates and the solenoid SL2 is energized to move the spool to the solenoid SL1 side (position A2), the first supply / discharge passage 34a and the first supply / discharge passage 35b are the first The supply / discharge passage 34b and the first supply / discharge passage 35a communicate with each other.

  Although the illustration of the second direction switching valve 32 is omitted when the solenoid SL3 is not excited, the spool disposed in the second direction switching valve 32 is held at the neutral position A0 by the elastic restoring force of the spring. In this state, the first supply / discharge passage 34b and the first supply / discharge passage 34c communicate with each other, the first supply / discharge passage 35b and the first supply / discharge passage 35c communicate with each other, and the second supply / discharge passages 36 and 37 are shut, respectively. . In the state where the solenoid SL3 is energized and the spool is moved in the direction against the elastic force of the spring, the first supply / discharge passage 34b and the second supply / discharge passage 36 are connected to the first supply / discharge passage 35b and the second supply / discharge passage 35b. The discharge passages 37 communicate with each other, and the first supply / discharge passages 34c and 35c are shut.

  In order to operate the solenoids SL1, SL2, and SL3 provided in the first direction switching valve 18 and the second direction switching valve 32, for example, an electric circuit as shown in FIG. 6 is configured.

  The electric circuit 38 includes a power source 39, a lift arm drive operation input circuit 40, an input arithmetic circuit 41, a solenoid drive circuit 42, a solenoid SL1, a solenoid SL2, and a solenoid SL3. In FIG. 6, reference numeral 43 denotes a three-point support device side changeover switch, and 44 denotes a three-point support device side control circuit.

  The lift arm drive operation input circuit 40 includes a variable resistor 45, and the resistance value of the variable resistor 45 is changed by, for example, tilting the loader operation lever 30 shown in FIG. Yes. When a signal corresponding to the resistance value changed by tilting the loader operation lever 30 is input to the input calculation circuit 41, the input calculation circuit 41 sends a command signal to the solenoid drive circuit 42 based on the calculation result for the input value. Put out. The excitation signal is sent to the solenoid to be excited by the solenoid drive circuit 42 that has received this command signal. In this embodiment, the loader operation lever 30 can be tilted in two directions, for example, the tilting operation in the forward direction is a lowering operation of the lift arm 6, and the tilting operation in the rearward direction is the lift arm 6. Corresponds to the ascending movement of each.

  The three-point support device side changeover switch 43 includes a changeover lever 43a and contacts 43b and 43c. For example, when the three-point support device operation switch 29 shown in FIG. 43c), the solenoid SL1 (solenoid SL2) is excited via the three-point support device side drive circuit 44. Further, in this embodiment, the three-point support device operation switch 29 can be tilted in two directions, for example, the tilting operation in the front direction is an operation for raising the left side in the vehicle width direction of the tiller 2 (the right side is The backward tilting operation corresponds to the operation of raising the right side of the tiller 2 in the vehicle width direction (the operation of lowering the left side).

  Next, the operation mode of the working machine hydraulic pressure take-out circuit 31 according to the present embodiment will be described.

  Since the resistance value of the variable resistor 45 does not fluctuate when the loader operation lever 30 and the three-point support device operation switch 29 are not tilted in any direction, the solenoid SL1, the solenoid SL2, and the solenoid SL3 are all Not excited. Therefore, the first direction switching valve 18 is in the neutral position A0, and pressure oil is not supplied to or discharged from the three-point support device horizontal control cylinder 3 or the lift arm drive cylinder 8. In this state, the second direction switching valve 32 is in the neutral position A0, and the first supply / discharge passage 34b and the first supply / discharge passage 34c communicate with each other, and the first supply / discharge passage 35b and the first supply / discharge passage 35c communicate with each other. Therefore, the oil supply system from the first direction switching valve 18 to the oil chamber 3a of the three-point support device horizontal control cylinder 3 and the oil drainage from the oil chamber 3b of the three-point support device horizontal control cylinder 3 to the first direction switching valve 18 A system is formed.

  When only the three-point support device operation switch 29 is tilted backward, for example, while the loader operation lever 30 is not tilted, only the solenoid SL1 is excited, and the first direction switching valve 18 is moved to the position A1 as shown in FIG. Switch to At this time, the second direction switching valve 32 maintains the state of the neutral position A0. In this state, the pressure oil sent from the hydraulic supply source 15 through the adjusting unit 16 is supplied to the first supply / discharge passage 34a, the first direction switching valve 18, the first supply / discharge passage 34b, the second direction switching valve 32, and The oil is supplied to the oil chamber 3a of the three-point support device horizontal control cylinder 3 through the first supply / discharge passage 34c. At the same time, the pressure oil discharged from the oil chamber 3b of the three-point support device horizontal control cylinder 3 is supplied to the first supply / discharge passage 35c, the second direction switching valve 32, the first supply / discharge passage 35b, the first direction switching valve 18, Then, the oil is drained to the oil tank 14 through the first supply / discharge passage 35a. As a result, the piston 3c is pushed toward the oil chamber 3b, and the piston rod 3d retracts.

  When only the three-point support device operation switch 29 is tilted forward, for example, only the solenoid SL2 is excited, and the first direction switching valve 18 is switched to the position A2, as shown in FIG. On the other hand, the second direction switching valve 32 maintains the state of the neutral position A0. In this state, the pressure oil sent from the hydraulic supply source 15 through the adjusting unit 16 is supplied to the first supply / discharge passage 34a, the first direction switching valve 18, the first supply / discharge passage 35b, the second direction switching valve 32, and The oil is supplied to the oil chamber 3b of the three-point support device horizontal control cylinder 3 through the first supply / discharge passage 35c. At the same time, the pressure oil discharged from the oil chamber 3a of the three-point support device horizontal control cylinder 3 is supplied to the first supply / discharge passage 34c, the second direction switching valve 32, the first supply / discharge passage 34b, the first direction switching valve 18, Then, the oil is drained to the oil tank 14 through the first supply / discharge passage 35a. As a result, the piston 3c is pushed toward the oil chamber 3b, and the piston rod 3d retracts. In this way, the three-point support device horizontal control cylinder 3 expands and contracts, and the tiller 2 is horizontally controlled.

  Next, when the loader operation lever 30 is tilted backward while the three-point support device operation switch 29 is not tilted in any direction, the variable resistor 45 provided in the lift arm drive operation input circuit 40. For example, the resistance value decreases. Based on the decreased resistance value, an operation is executed by the input operation circuit 41, and an excitation signal is sent from the solenoid drive circuit 42 to the solenoid to be excited based on the operation result. In this embodiment, the solenoid SL1 and the solenoid SL3 are excited, whereby the first direction switching valve 18 and the second direction switching valve 32 are respectively switched to the position A1 as shown in FIG. In this state, the first supply / discharge passage 34b and the second supply / discharge passage 36 communicate with each other, and the first supply / discharge passage 35b and the second supply / discharge passage 37 communicate with each other. An oil supply system to the oil chamber 8 a of the cylinder 8 and an oil discharge system from the oil chamber 8 b of the lift arm drive cylinder 8 to the first direction switching valve 18 are formed.

  In this state, the pressure oil sent from the hydraulic supply source 15 through the adjusting unit 16 is supplied to the first supply / discharge passage 34a, the first direction switching valve 18, the first supply / discharge passage 34b, the second direction switching valve 32, and the second. The oil is supplied to the oil chamber 8 a of the lift arm drive cylinder 8 through the two supply / discharge passages 36. On the other hand, the pressure oil discharged from the oil chamber 8b of the lift arm drive cylinder 8 is the second supply / discharge passage 37, the second direction switching valve 32, the first supply / discharge passage 35b, the first direction switching valve 18, and The oil is drained to the oil tank 14 through the first supply / discharge passage 35a. As a result, the piston 8c is pushed to the oil chamber 8b side, and the piston rod 8d extends to raise the lift arm 6 of the loader 5.

  When the loader operation lever 30 is tilted forward, the resistance value of the variable resistor 45 provided in the lift arm drive operation input circuit 40 increases, for example. Based on the increased resistance value, calculation is performed by the input calculation circuit 41, and an excitation signal is sent from the solenoid drive circuit 42 to the solenoid to be excited based on the calculation result. In this embodiment, the solenoid SL2 and the solenoid SL3 are excited, whereby the first direction switching valve 18 is switched to the position A2 as shown in FIG. On the other hand, the second direction switching valve 32 maintains the state of the position A1.

  In this state, the pressure oil sent from the hydraulic supply source 15 through the adjusting unit 16 is supplied to the first supply / discharge passage 34a, the first direction switching valve 18, the first supply / discharge passage 35b, the second direction switching valve 32, and The oil is supplied to the oil chamber 8 b of the lift arm drive cylinder 8 through the second supply / discharge passage 37. At the same time, the pressure oil discharged from the oil chamber 8a of the lift arm drive cylinder 8 is supplied to the second supply / discharge passage 36, the second direction switching valve 32, the first supply / discharge passage 34b, the first direction switching valve 18, and the first. Drain to the oil tank 14 through the supply / discharge passage 35a. As a result, the piston 8c is pushed toward the oil chamber 8a, and the piston rod 8d retracts, whereby the lift arm 6 of the loader 5 is lowered.

  As described above, the working machine hydraulic pressure take-out circuit 31 according to this embodiment includes the second direction switching valve in the first supply / discharge passages 34 and 35 that connect the first direction switching valve 18 and the three-point support device horizontal control cylinder 3. 32 is arranged in series with respect to the first direction switching valve 18, and the second direction switching valve 32 and the lift arm drive cylinder 8 are connected via the second supply / discharge passages 36 and 37 to drive the lift arm. Since the switching operation between the forward movement and the backward movement of the cylinder 8 is performed by the first direction switching valve 18, the second direction switching valve 32 is configured to supply and discharge pressure oil to the three-point support device horizontal control cylinder 3 and lift. It is only necessary to selectively perform supply and discharge of pressure oil to and from the arm drive cylinder 8. As a result, the second direction switching valve 32 can be replaced with a two-position / one-solenoid type that is cheaper than the three-position / two-solenoid type, and the cost required for the working machine hydraulic pressure take-out circuit 31 can be reduced. it can.

  Further, the first supply / discharge passages 34a and 35a connecting the hydraulic pressure supply source 15 and the first direction switching valve 18 and the first supply / discharge passages 34b and 35b connecting the first direction switching valve 18 and the second direction switching valve 21 are provided. Since the piping can be simplified by sharing the supply / discharge system on the three-point support device horizontal control cylinder 3 side and the supply / discharge system on the lift arm drive cylinder 8 side, the hydraulic take-out circuit 31 for the work machine can be made compact. Can be planned.

  Moreover, since the number of solenoids excited by the signal from the solenoid drive circuit 42 is reduced by making the second direction switching valve 32 a 2-position 1 solenoid type, the solenoid drive circuit 42 is further simplified. Can be replaced. As a result, the electric circuit 38 can be simplified and the cost can be reduced.

  Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and other embodiments can be adopted.

  FIG. 7 shows a working machine hydraulic pressure take-out circuit 46 from a tractor according to a second embodiment of the present invention. The work machine hydraulic pressure take-out circuit 46 includes a plurality of work machine drive actuators 33B, and includes, for example, a lift arm drive cylinder 8 that drives a lift arm of a loader and a loader attachment drive cylinder 9 that drives a loader attachment. On the other hand, a plurality of second direction switching valves 32 are provided. For example, the second direction switching valve 47 is interposed in the second supply / discharge passages 36 and 37 connecting the second direction switching valve 32 and the lift arm drive cylinder 8, and the second The construction differs from the working machine hydraulic pressure take-out circuit 31 according to the first embodiment in that the direction switching valve 47 and the loader attachment drive cylinder 9 are connected via the second supply / discharge passages 48 and 49.

  In this illustrated example, the second direction switching valve 47 is a 6-port 2-position 1 solenoid type direction switching valve. Two ports provided on the second direction switching valve 32 side are connected to the second supply / discharge passages 36a and 37a. The second direction switching valve 32 is connected to two ports provided on the lift arm drive cylinder 8 side. Of the remaining 4 ports, 2 ports provided on the lift arm drive cylinder 8 side are connected to the oil chambers 8a, 8b of the lift arm drive cylinder 8 via the second supply / discharge passages 36b, 37b, respectively. Two ports provided on the loader attachment drive cylinder 9 side are connected to oil chambers 9a and 9b of the loader attachment drive cylinder 9 via second supply / discharge passages 48 and 49, respectively.

  Similarly to the second direction switching valve 32, the second direction switching valve 47 is held at the neutral position A0 when the solenoid SL4 is not excited. In this state, the second supply / discharge passage 36a and the second supply / discharge passage 36b communicate with each other, the second supply / discharge passage 37a and the second supply / discharge passage 37b communicate with each other, and the second supply / discharge passages 48 and 49 are shut, respectively. . When the solenoid SL4 is energized, the second supply / discharge passage 36a and the second supply / discharge passage 48 communicate with the second supply / discharge passage 37a and the second supply / discharge passage 49, respectively, and the second supply / discharge passage 36b, Each of 37b is shut.

  In order to operate the solenoids SL1, SL2, SL3, SL4 provided in the first direction switching valve 18, the second direction switching valve 32, and the second direction switching valve 47, for example, an electric circuit as shown in FIG. Composed.

  This electric circuit 50 is different from the electric circuit 38 shown in FIG. 6 in that a loader attachment drive operation input circuit 51 and a solenoid SL4 are newly connected as compared with the electric circuit 38 shown in FIG. The loader attachment drive operation input circuit 51 includes a variable resistor 52, and the resistance value of the variable resistor 52 is changed by, for example, tilting the loader operation lever 30 shown in FIG. Yes. Further, when the resistance value of the variable resistor 52 varies, the input arithmetic circuit 53 issues a command signal to the solenoid drive circuit 54 based on the arithmetic result for the input value from the variable resistor 52. In response to the command signal, the solenoid drive circuit 54 sends an excitation signal to the solenoid to be excited. In this embodiment, the loader operation lever 30 can be tilted in four directions, front and rear, left and right. For example, the tilting operation in the front and rear direction is performed when the lift arm 6 is lifted and lowered and tilted left and right. The operation corresponds to a loader attachment 7, for example, a squeegee such as a bucket and a dumping operation.

  Next, an operation mode of the working machine hydraulic pressure take-out circuit 46 according to the present embodiment will be described. In this embodiment, only the drive operation of the loader side drive cylinder (lift arm drive cylinder 8 and attachment drive cylinder 9) will be mainly described. The operating mode of the hydraulic pressure take-out circuit 46 for the work machine when the three-point support device operation switch 29 is operated to drive the three-point support device horizontal control cylinder 3 depends on the state of the second direction switching valve 47 (switching position). ), And the same supply / discharge path as in the first embodiment is followed.

  When the loader operation lever 30 is not tilted in any direction, front, back, left, or right, the resistance values of the variable resistors 45 and 52 do not fluctuate. . Therefore, as shown in FIG. 7, the first direction switching valve 18 is in the neutral position A0, and pressure oil is applied to the three-point support device horizontal control cylinder 3, the lift arm drive cylinder 8, and the loader attachment drive cylinder 9. It is designed not to be supplied or discharged. In this state, the second direction switching valves 32 and 47 are in the neutral positions A0 and A0, respectively, and the first supply / discharge passage 34b and the first supply / discharge passage 34c, and the first supply / discharge passage 35b and the first supply / discharge passage 35c are provided. Each communicates. Thus, the oil supply system from the first direction switching valve 18 to the oil chamber 3a of the three-point support device horizontal control cylinder 3 and the oil drainage from the oil chamber 3b of the three-point support device horizontal control cylinder 3 to the first direction switching valve 18 A system is formed.

  When the loader operation lever 30 is tilted backward, only the resistance value of the variable resistor 45 provided in the lift arm drive operation input circuit 40 decreases, for example. As a result, the solenoid SL1 and the solenoid SL3 are excited, and the first direction switching valve 18 is switched to the position A1 and the second direction switching valve 32 is switched to the position A1, as shown in FIG. In this state, the first supply / discharge passage 34a and the first supply / discharge passage 34b, the first supply / discharge passage 35a and the second supply / discharge passage 35b communicate with each other, and the first supply / discharge passage 34b and the second supply / discharge passage 36a, The first supply / discharge passage 35b and the second supply / discharge passage 37a communicate with each other. Since the second direction switching valve 47 maintains the neutral position A0, the second supply / discharge passage 36a and the second supply / discharge passage 36b, and the second supply / discharge passage 37a and the second supply / discharge passage 37b communicate with each other. As a result, an oil supply system from the first direction switching valve 18 to the oil chamber 8a of the lift arm drive cylinder 8 and an oil discharge system from the oil chamber 8b of the lift arm drive cylinder 8 to the first direction switch valve 18 are formed.

  In this state, the pressure oil delivered from the hydraulic supply source 15 through the adjusting unit 16 is supplied to the first supply / discharge passage 34a, the first direction switching valve 18, the first supply / discharge passage 34b, the second direction switching valve 32, the second The oil is supplied to the oil chamber 8a of the lift arm drive cylinder 8 through the supply / discharge passage 36a, the second direction switching valve 47, and the second supply / discharge passage 36b. On the other hand, the pressure oil discharged from the oil chamber 8b of the lift arm drive cylinder 8 is supplied to the second supply / discharge passage 37b, the second direction switching valve 47, the second supply / discharge passage 37a, the second direction switching valve 32, and the second. The oil is drained to the oil tank 14 through the one supply / discharge passage 35b, the first direction switching valve 18, and the first supply / discharge passage 35a. As a result, the piston 8c is pushed to the oil chamber 8b side, and the piston rod 8d extends to raise the lift arm 6 of the loader 5.

  When the loader operation lever 30 is tilted forward, only the resistance value of the variable resistor 45 provided in the lift arm drive operation input circuit 40 increases, for example. Thereby, the solenoid SL2 and the solenoid SL3 are energized, and the first direction switching valve 18 is switched to the position A2, as shown in FIG. At this time, the second direction switching valve 32 maintains the state of the position A1, and the second direction switching valve 47 maintains the state of the neutral position A0.

  In this state, the pressure oil sent from the hydraulic pressure supply source 15 through the adjustment unit 16 is the first supply / discharge passage 34a, the first direction switching valve 18, the first supply / discharge passage 35b, the second direction switching valve 32, the second The oil is supplied to the oil chamber 8b of the lift arm drive cylinder 8 through the two supply / discharge passages 37a, the second direction switching valve 47, and the second supply / discharge passage 37b. At the same time, the pressure oil discharged from the oil chamber 8a of the lift arm drive cylinder 8 is supplied to the second supply / discharge passage 36b, the second direction switching valve 47, the second supply / discharge passage 36a, the second direction switching valve 32, and the first supply valve. The oil is drained to the oil tank 14 through the discharge passage 34b, the first direction switching valve 18, and the first supply / discharge passage 35a. As a result, the piston 8c is pushed toward the oil chamber 8a, and the piston rod 8d retracts, whereby the lift arm 6 of the loader 5 is lowered.

  When the loader operation lever 30 is tilted to the left, only the resistance value of the variable resistor 52 provided in the loader attachment drive operation input circuit 51 decreases, for example. As a result, the solenoid SL1, the solenoid SL3, and the solenoid SL4 are energized, and as shown in FIG. 10, the first direction switching valve 18 is switched to the position A1, and the second direction switching valve 47 is switched to the position A1. At this time, the second direction switching valve 32 maintains the state of the position A1. In this state, the first supply / discharge passage 34a and the first supply / discharge passage 34b, the first supply / discharge passage 35a and the first supply / discharge passage 35b communicate with each other, and the first supply / discharge passage 34b and the second supply / discharge passage 36a, The first supply / discharge passage 34b and the second supply / discharge passage 37a communicate with each other. The second supply / discharge passage 36a and the second supply / discharge passage 48, and the second supply / discharge passage 37a and the second supply / discharge passage 49 communicate with each other. As a result, an oil supply system from the first direction switching valve 18 to the oil chamber 9a of the loader attachment drive cylinder 9 and an oil discharge system from the oil chamber 9b of the loader attachment drive cylinder 9 to the first direction switching valve 18 are formed.

  In this state, the pressure oil delivered from the hydraulic supply source 15 through the adjusting unit 16 is supplied to the first supply / discharge passage 34a, the first direction switching valve 18, the first supply / discharge passage 34b, the second direction switching valve 32, the second The oil is supplied to the oil chamber 9a of the loader attachment drive cylinder 9 through the supply / discharge passage 36a, the second direction switching valve 47, and the second supply / discharge passage 48. On the other hand, the pressure oil discharged from the oil chamber 9b of the loader attachment drive cylinder 9 is supplied to the second supply / discharge passage 49, the second direction switching valve 47, the second supply / discharge passage 37a, the second direction switching valve 32, and the second. The oil is drained to the oil tank 14 through the one supply / discharge passage 35b, the first direction switching valve 18, and the first supply / discharge passage 35a. As a result, the piston 9c is pushed toward the oil chamber 9b, and the piston rod 9d retracts, whereby the loader attachment 7, for example, the bucket performs a squeeze operation.

  When the loader operation lever 30 is tilted to the right, only the resistance value of the variable resistor 52 provided in the loader attachment drive operation input circuit 51 is increased, for example. As a result, the solenoid SL2, the solenoid SL3, and the solenoid SL4 are energized, and as shown in FIG. 11, the first direction switching valve 18 is switched to the position A2, while the second direction switching valve 32 and the second direction switching valve 47 are Each holds the state of the position A1.

  In this state, the pressure oil sent from the hydraulic pressure supply source 15 through the adjustment unit 16 is the first supply / discharge passage 34a, the first direction switching valve 18, the first supply / discharge passage 35b, the second direction switching valve 32, the second The oil is supplied to the oil chamber 9b of the loader attachment drive cylinder 9 through the two supply / discharge passages 37a, the second direction switching valve 47, and the second supply / discharge passage 49. At the same time, the pressure oil discharged from the oil chamber 9a of the loader attachment drive cylinder 9 is supplied to the second supply / discharge passage 48, the second direction switching valve 47, the second supply / discharge passage 36a, the second direction switching valve 32, and the first supply. The oil is drained to the oil tank 14 through the discharge passage 34b, the first direction switching valve 18, and the first supply / discharge passage 35a. As a result, the piston 9c is pushed toward the oil chamber 9a, and the piston rod 9d extends, whereby the loader attachment 7, for example, the bucket performs a dumping operation.

  As described above, the working machine hydraulic pressure take-out circuit 46 according to the present embodiment includes the second direction switching valve in the first supply / discharge passages 34 and 35 connecting the first direction switching valve 18 and the three-point support device horizontal control cylinder 3. 32 is arranged in series with respect to the first direction switching valve 18, and further, the second direction switching valve 47 is connected to the second supply / discharge passages 36, 37 connecting the second direction switching valve 32 and the lift arm drive cylinder 8. And the switching operation of the forward and backward movements of the lift arm drive cylinder 8 or the loader attachment drive cylinder 9 is performed by the first direction switching valve 18, so that the second direction switching valve 47 is driven by the lift arm drive. It is only necessary to selectively perform supply and discharge of pressure oil to and from the cylinder 8 and supply and discharge of pressure oil to the loader attachment drive cylinder 9. As a result, both of the second direction switching valves 32 and 47 can be replaced with those of the 2-position 1 solenoid type, which is less expensive than the 3-position 2-solenoid type, and the cost for the hydraulic pressure take-out circuit 46 for the working machine is greatly increased. Can be reduced.

  13 shows the first supply / discharge passages 34c and 35c between the second direction switching valve 32 and the three-point support device horizontal control cylinder 3, and the second supply between the second direction switching valve 32 and the lift arm drive cylinder 8. FIG. A work machine hydraulic pressure take-out circuit 56 from a tractor in which pilot check valves 55 are interposed in the exhaust passages 36 and 37 is shown. By configuring in this way, it is possible for pressure oil to flow back through the desired hydraulic supply / discharge path from the three-point support device horizontal control cylinder 3 or from the lift arm drive cylinder 8 toward the second direction switching valve 32. Since it can be prevented completely, for example, the working machine (loader 5 or the like) driven by each drive cylinder can be prevented from descending by its own weight in the stopped state or by the weight of the work object. Further, although not shown, a pilot check valve 55 may be interposed in the second supply / discharge passages 48 and 49 between the second direction switching valve 47 and the loader attachment drive cylinder 9.

  If a proportional type solenoid is used, the speed of each cylinder can be adjusted by configuring an electric circuit in combination with a variable resistor. As shown in FIG. 14, the variable resistors 45 and 52 can be replaced with mechanical changeover switches 57 and 58. Thereby, the input arithmetic circuit 53 can be replaced with a more simplified one, and the electric circuit can be further simplified, and the cost can be reduced.

  In the above-described embodiment, the three-point support device lift cylinder 4 is a single-acting type. However, the three-point support device lift cylinder 4 is a double-acting type, and the three-point support device lift cylinder 4 is moved forward and backward. Alternatively, when a directional switching valve that can be switched to any one of the stopped states is provided, the second directional switching valve 32 is interposed in the supply / discharge passage connecting the directional switching valve and the three-point support device lift cylinder. The cost can be reduced in the same manner as in the above-described embodiment. Also, if the loader-side drive cylinder (lift arm drive cylinder 8 or loader attachment drive cylinder 9), which was a double-acting type in the above-described embodiment, is a single-acting type, a directional switching valve and a single-acting three-point support are provided. The second direction switching valve 32 can be interposed in the supply / exhaust passage connecting the device lift cylinder 4, and the cost can be reduced as in the above-described embodiment. The place where the second direction switching valve 32 can be disposed is not limited to the above-described place, and the cylinder that is not driven simultaneously with the lift arm drive cylinder 8 and the loader attachment drive cylinder 9 and the drive state of the cylinder are switched. As long as it is a three-position two-solenoid valve, it can be interposed between any cylinder and the direction switching valve.

  The second directional switching valve 32 interposed between each driving cylinder and each directional switching valve described above was an electromagnetic valve that electrically drives the spool, but can be replaced with a manual valve. Significant cost reductions such as cost reduction of the switching valve itself and further simplification of the electric circuit can be achieved.

  The case where the loader 5 is used by being attached to the front side of the tractor 1 has been described above, but the present invention is not limited to this usage pattern. For example, as shown in FIG. 15, the present invention can also be applied to the case where the boom type mower 5 a is attached to the front side of the tractor 1. Alternatively, as shown in FIG. 16, the present invention can be similarly applied to a case where the boom type mower 5 a is attached to the rear surface side of the tractor 1. In this case, for example, a hydraulic motor or the like can be used as the work machine drive actuator 33B in addition to the hydraulic cylinder. In this case, the boom type mower 5a attached to the rear side of the tractor 1 corresponds to the tractor working machine.

  As described above, the present invention is not limited to the loader 5 or the boom type mower 5a, and can be applied to all tractor work machines as long as it includes a cylinder driven by hydraulic take-out from the hydraulic take-out circuit. It is possible to apply.

  In the first and second embodiments described above, the case where one or two work implement drive actuators 33B are provided in the tractor work implement such as the loader 5 is described. Of course, the present invention can also be applied to a tractor work machine including the machine drive actuator 33B. In that case, the same number of second direction switching valves 32 and 47 as the work machine drive actuator 33B may be provided. Or although illustration is abbreviate | omitted, the multiple direction direction switching valve which integrated two or more 2nd direction switching valves 32 and 47 can also be used, and in this case, several actuator drive actuators are used. It is only necessary to provide a number of multiple directional switching valves smaller than the number of one or the plurality of work implement drive actuators 33B. Of course, the multiple direction switching valve and the second direction switching valves 32 and 47 may be used in appropriate combination according to the number of work implement drive actuators 33B.

The figure which shows the hydraulic pressure taking-out circuit for working machines from the tractor which concerns on 1st Embodiment of this invention. The figure which shows the operation | movement aspect of the hydraulic pressure take-out circuit for working machines from the tractor which concerns on 1st Embodiment. The figure which shows the operation | movement aspect of the hydraulic pressure take-out circuit for working machines from the tractor which concerns on 1st Embodiment. The figure which shows the operation | movement aspect of the hydraulic pressure take-out circuit for working machines from the tractor which concerns on 1st Embodiment. The figure which shows the operation | movement aspect of the hydraulic pressure take-out circuit for working machines from the tractor which concerns on 1st Embodiment. The figure which shows the electric circuit of the tractor which concerns on 1st Embodiment. The figure which shows the hydraulic pressure take-out circuit for working machines from the tractor which concerns on 2nd Embodiment. The figure which shows the operation | movement aspect of the hydraulic pressure take-out circuit for working machines from the tractor which concerns on 2nd Embodiment. The figure which shows the operation | movement aspect of the hydraulic pressure take-out circuit for working machines from the tractor which concerns on 2nd Embodiment. The figure which shows the operation | movement aspect of the hydraulic pressure take-out circuit for working machines from the tractor which concerns on 2nd Embodiment. The figure which shows the operation | movement aspect of the hydraulic pressure take-out circuit for working machines from the tractor which concerns on 2nd Embodiment. The figure which shows the electric circuit of the tractor which concerns on 2nd Embodiment. The figure which shows the modification of the hydraulic pressure take-out circuit for working machines from the tractor which concerns on 1st Embodiment. The figure which shows the modification of the electric circuit of the tractor which concerns on 2nd Embodiment. The side view of the tractor which attached the boom type mower to the front side. The side view of the tractor which attached the boom type mower to the rear side. The side view of the tractor which attached the tiller to the back side. The side view of the tractor which attached the loader to the front side. The figure which shows the hydraulic pressure take-out circuit for working machines from the conventional tractor. The figure which shows the operation | movement aspect of the hydraulic take-out circuit for working machines from the conventional tractor. The figure which shows the operation | movement aspect of the hydraulic take-out circuit for working machines from the conventional tractor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tractor 2 Tiller 3 Three-point support device horizontal control cylinders 3a and 3b Oil chamber 4 Three-point support device Lift cylinder 5 Loader 5a Boom mower 6 Lift arm 7 Loader attachment 8 Lift arm drive cylinders 8a and 8b Oil chamber 9 Loader Attachment drive cylinders 9a, 9b Oil chambers 11, 31, 46, 56 Working machine hydraulic take-out circuit 13 Hydraulic pump 14 Oil tank 15 Hydraulic supply source 18 First direction switching valve 29 Three-point support device operation switch 30 Loader operation lever 32, 47 Second direction switching valve 33A Three-point support device drive cylinder 33B Work implement drive actuators 34, 34a, 34b, 34c, 35, 35a, 35b, 35c First supply / discharge passages 36, 36a, 36b, 37, 37a, 37b, 48, 49 Second supply / discharge passage 38, 50 Electric circuit 40 Lifter Arm driving operation input circuit 41 and 53 input the arithmetic circuit 42, 54 solenoid driver circuit 43 three-point supporting device side changeover switch SL1, SL2, SL3, SL4 solenoid

Claims (4)

Connecting a hydraulic supply source having a hydraulic pump, a three-point support device driving cylinder connected to the hydraulic supply source and driving a three-point support device mounted on the rear surface side of the tractor, and a hydraulic supply source and a three-point support device drive cylinder A tractor work machine is attached to a tractor having a first directional switching valve for switching a three-point support device drive cylinder to one of forward, backward, and stopped states in the first supply / discharge passage of pressure oil In the working machine hydraulic pressure take-out circuit from the tractor for taking out the working machine hydraulic pressure for operating the working machine drive actuator that drives the tractor working machine from the tractor side,
The second direction switching valve is interposed in the first supply / discharge passage between the first direction switching valve and the three-point support device drive cylinder, and the second direction switching valve and the work implement drive actuator are connected via the second supply / discharge passage. By connecting and selecting the second direction switching valve, the supply / discharge system from the first direction switching valve to the three-point support device drive cylinder can be switched to the supply / discharge system from the first direction switching valve to the work machine drive actuator. A hydraulic take-out circuit for a work machine from a tractor. A plurality of the work machine drive actuators are provided, and one or a plurality of the second direction switching valves are provided,
The plurality of work implement drive actuators and the one or more second direction switching valves are continuously connected, and a three-point support device driving cylinder is selected from the hydraulic supply source by an operation of selecting the one or more second direction switching valves. The hydraulic take-out circuit for work implements from a tractor according to claim 1, wherein a supply / exhaust system to each work implement drive actuator including the above can be selected alternatively.   3. The hydraulic extraction circuit for a working machine from the tractor according to claim 1, wherein the working machine for the tractor is a loader and is attached to a front side of the tractor.   2. The hydraulic extractor circuit for a working machine from a tractor according to claim 1, wherein the working machine for a tractor is a boom type mower and is attached to a front side or a rear side of the tractor.