US20120048409A9 - Hydraulic Circuit For Working Machine - Google Patents
Hydraulic Circuit For Working Machine Download PDFInfo
- Publication number
- US20120048409A9 US20120048409A9 US13/061,678 US200913061678A US2012048409A9 US 20120048409 A9 US20120048409 A9 US 20120048409A9 US 200913061678 A US200913061678 A US 200913061678A US 2012048409 A9 US2012048409 A9 US 2012048409A9
- Authority
- US
- United States
- Prior art keywords
- switching valve
- mode switching
- lever
- pto
- switched
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000007246 mechanism Effects 0.000 claims description 50
- 230000005764 inhibitory process Effects 0.000 claims description 5
- 239000010720 hydraulic oil Substances 0.000 abstract 6
- 239000003921 oil Substances 0.000 abstract 1
- 238000010276 construction Methods 0.000 description 18
- 239000003381 stabilizer Substances 0.000 description 15
- 230000002093 peripheral effect Effects 0.000 description 10
- 239000004576 sand Substances 0.000 description 8
- 238000009412 basement excavation Methods 0.000 description 6
- 239000011800 void material Substances 0.000 description 3
- 238000013016 damping Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 238000013021 overheating Methods 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2221—Control of flow rate; Load sensing arrangements
- E02F9/2239—Control of flow rate; Load sensing arrangements using two or more pumps with cross-assistance
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/2004—Control mechanisms, e.g. control levers
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2278—Hydraulic circuits
- E02F9/2292—Systems with two or more pumps
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2278—Hydraulic circuits
- E02F9/2296—Systems with a variable displacement pump
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
- F15B11/17—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors using two or more pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
- F15B2211/205—Systems with pumps
- F15B2211/2053—Type of pump
- F15B2211/20546—Type of pump variable capacity
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
- F15B2211/205—Systems with pumps
- F15B2211/20576—Systems with pumps with multiple pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/30—Directional control
- F15B2211/31—Directional control characterised by the positions of the valve element
- F15B2211/3105—Neutral or centre positions
- F15B2211/3116—Neutral or centre positions the pump port being open in the centre position, e.g. so-called open centre
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/30—Directional control
- F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
- F15B2211/31523—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source and an output member
- F15B2211/31541—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source and an output member having a single pressure source and multiple output members
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/50—Pressure control
- F15B2211/505—Pressure control characterised by the type of pressure control means
- F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
- F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/50—Pressure control
- F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
- F15B2211/5157—Pressure control characterised by the connections of the pressure control means in the circuit being connected to a pressure source and a return line
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/50—Pressure control
- F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
- F15B2211/5159—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a return line
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/50—Pressure control
- F15B2211/55—Pressure control for limiting a pressure up to a maximum pressure, e.g. by using a pressure relief valve
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
- F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
- F15B2211/7142—Multiple output members, e.g. multiple hydraulic motors or cylinders the output members being arranged in multiple groups
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T137/00—Fluid handling
- Y10T137/8593—Systems
- Y10T137/85978—With pump
- Y10T137/86131—Plural
Definitions
- the present invention relates to an art of a working vehicle having two or more hydraulic pumps.
- a hydraulic circuit of the working vehicle has a loader control valve 500 shown in FIG. 14 .
- Pressure oil sent by one of the two hydraulic pumps is supplied through a pipe 536 and a pump port 551 to the loader control valve 500 .
- a damping cylinder switching valve 510 and a bucket lifting cylinder switching valve 520 With the pressure oil sent by the one of the hydraulic pumps, the operation of two damping cylinders 518 and two bucket lifting cylinders 517 can be switched, in its turn operation of a loader (not shown) can be controlled.
- the pressure oil sent by the one of the hydraulic pumps can be extracted through PTO ports 560 and 561 .
- Another working machine connected to the working vehicle can be driven with the extracted pressure oil.
- the pressure oil extracted through the PTO switching valve may be unable to drive a working machine requiring large flow rate.
- the discharge amount of the pressure oil by the one of the hydraulic pumps is about 10 GPM (gallon/minute)
- a working machine requiring 17 GPM of pressure oil cannot be driven.
- the present invention is provided in consideration of the above problems, and the purpose of the present invention is to provide a working vehicle in which pressure oil pressingly sent by two hydraulic pumps can be combined and extracted.
- the present invention includes two or more hydraulic pumps independent of each other and pressingly sending pressure oil, a mode switching valve which can be switched to a confluence position at which the pressure oil pressingly sent by the two or more hydraulic pumps is combined, a PTO port at which the pressure oil is extracted, and a PTO switching valve arranged downstream the mode switching valve and switched so as to send pressingly the pressure oil to the PTO port.
- the mode switching valve is provided integrally in a control valve having the PTO switching valve.
- the mode switching valve can be switched among the confluence position, a return position at which the pressure oil pressingly sent by the two hydraulic pumps is returned to a tank, and a working position at which the pressure oil pressingly sent by the two hydraulic pumps is pressingly sent to the other control valves respectively arranged at the downstream sides without combining the pressure oil.
- the interlock mechanism is constructed so that, when the PTO switching valve is switched from the continuous position to the other position, the mode switching valve is switched from the confluence position to the other position.
- the interlock mechanism is constructed so that, in the middle of switching of the PTO switching valve from the continuous position to the other position, the mode switching valve is moved to a position across the position other than the confluence position for a predetermined dimension.
- the present invention constructed as the above brings the following effects.
- the pressure oil pressingly sent by the hydraulic pumps independent of each other can be combined and the combined pressure oil can be extracted through the PTO port. Accordingly, a working machine requiring large flow rate can be driven.
- any space is not required for arranging the mode switching valve, whereby the space can be saved.
- any piping connecting the mode switching valve to the control valve is not required, whereby the part number and cost can be reduced.
- the pressure oil pressingly sent by the two or more hydraulic pumps can be combined only in the case that the pressure oil is extracted from the PTO port regularly (continuously). Only by switching the PTO switching valve from the continuous position, the combining of the pressure oil can be stopped.
- the mode switching valve can be switched certainly to the position other than the confluence position.
- the working machine connected to the PTO port is prevented from being driven simultaneously to the starting of the engine. Accordingly, the safety of the working machine can be improved.
- the rising of temperature of the combined pressure oil K can be suppressed. Accordingly, extraordinariness such as overheating can be prevented.
- FIG. 1 It is a right side view of entire construction of a working vehicle according to an embodiment of the present invention.
- FIG. 2 It is an entire schematic drawing of a hydraulic circuit provided in the working vehicle.
- FIG. 3 It is a partially enlarged drawing of the hydraulic circuit.
- FIG. 4 It is a left side view of a loader operation device.
- FIG. 5 It is an enlarged left side view of the action mode of the loader operation device.
- FIG. 6 It is an enlarged left side view of the action mode of the loader operation device.
- FIG. 7 It is an enlarged left side view of the action mode of the loader operation device.
- FIG. 8 It is an enlarged left side view of the action mode of the loader operation device.
- FIG. 9 It is an enlarged left side view of the action mode of the loader operation device.
- FIG. 10 It is a left side view of an engine rotational speed restriction means.
- FIG. 11 It is an enlarged left side view of the action mode of the engine rotational speed restriction means.
- FIG. 12 It is a left side view of another embodiment of the engine rotational speed restriction means.
- FIG. 13 It is a left side view of another embodiment of the engine rotational speed restriction means.
- FIG. 14 It is a drawing of a conventional hydraulic circuit.
- the working vehicle 1 performs conveyance work and excavation work of earth and sand and the like with a working device.
- the working vehicle 1 mainly has a traveling vehicle 2 , a loader 3 and a backhoe 4 .
- the traveling vehicle 2 is a main body of the working vehicle 1 .
- the traveling vehicle 2 mainly has a body frame 5 , an engine 6 , a bonnet 7 , two front wheels 8 , two rear wheels 9 and an operation part 10 .
- the body frame 5 is a main structure of the traveling vehicle 2 .
- the body frame 5 is a substantially box-like member formed from a plurality of plate members while the lengthwise direction thereof is in agreement with the longitudinal direction.
- the engine 6 generates power for driving the working vehicle 1 .
- the engine 6 is provided in the front portion of the body frame 5 .
- the bonnet 7 covers apparatuses such as the engine 6 provided in the traveling vehicle 2 .
- the bonnet 7 is provided in the front portion of the body frame 5 .
- the bonnet 7 is constructed so as to cover the apparatuses such as the engine 6 provided in the front portion of the body frame 5 .
- the front wheels 8 support the body frame 5 .
- the front wheels 8 are provided respectively at the left and right of the lower front portion of the body frame 5 .
- the front wheels 8 are rotated by the power generated by the engine 6 .
- the rear wheels 9 support the body frame 5 .
- the rear wheels 9 are provided respectively at the left and right of the lower rear portion of the body frame 5 .
- the rear wheels 9 are rotated by the power generated by the engine 6 .
- the operation part 10 is a position in which an operator operates the working vehicle 1 .
- the operation part 10 is provided at the substantially longitudinal center of the body frame 5 .
- the operation part 10 mainly has a steering wheel 11 , a seat 12 , a loader operation device 300 and a backhoe operation device 13 .
- the steering wheel 11 is a member for steering the front wheels 8 .
- the steering wheel 11 is provided in the front portion of the operation part 10 .
- the seat 12 is a member on which an operator sits.
- the seat 12 is provided behind the steering wheel 11 .
- the loader operation device 300 operates the working device such as the loader 3 and sets the engine rotational speed of the working vehicle 1 and the like.
- the loader operation device 300 is provided at the side (in this embodiment, the right side) of the seat 12 .
- the backhoe operation device 13 operates the backhoe 4 and the like.
- the backhoe operation device 13 is provided behind the seat 12 .
- the loader 3 is a working device for conveying earth and sand.
- the loader 3 mainly has two bucket lift arms 15 , a loader bucket 16 , two bucket lift cylinders 17 and two dump cylinders 18 .
- the bucket lift arms 15 are a main structure of the loader 3 .
- the rear ends of the bucket lift arms 15 are respectively supported rotatably on the left and right portions of the body frame 5 .
- the loader bucket 16 is a member loaded with the earth and sand.
- the loader bucket 16 is rotatably vertically supported at the front ends of the bucket lift arms 15 .
- the bucket lift cylinders 17 are hydraulic cylinders which can be controlled to expand and contract by the loader operation device 300 .
- the rear ends of the bucket lift cylinders 17 are respectively supported rotatably vertically on the left and right portions of the body frame 5 .
- the front ends of the bucket lift cylinders 17 are respectively supported rotatably vertically on the middle portions of the bucket lift arms 15 .
- the dump cylinders 18 are hydraulic cylinders which can be controlled to expand and contract by the loader operation device 300 .
- the rear ends of the dump cylinders 18 are respectively supported rotatably vertically on the left and right portions of the body frame 5 .
- the front ends of the dump cylinders 18 are connected respectively through two link mechanisms 19 to the loader bucket 16 .
- the bucket lift arms 15 can be moved vertically.
- the loader bucket 16 can be rotated vertically about the bucket lift arms 15 .
- the working vehicle 1 By combining the rotational actions of the bucket lift arms 15 and the loader bucket 16 , the working vehicle 1 performs conveyance work of earth and sand.
- the backhoe 4 performs excavation work of earth and sand.
- the backhoe 4 mainly has two stabilizers 20 , two stabilizer cylinders 21 , a boom bracket 22 , two swing cylinders 23 , a boom 24 , a boom cylinder 25 , an arm 26 , an arm cylinder 27 , a bucket 28 and a bucket cylinder 29 .
- the stabilizers 20 support the working vehicle 1 at the time of the excavation work with the backhoe 4 .
- One of ends of each of the stabilizers 20 is supported rotatably vertically at corresponding one of the left and right sides of the rear portion of the body frame 5 .
- the stabilizer cylinders 21 are hydraulic cylinders which can be controlled to expand and contract by the backhoe operation device 13 .
- One of ends of each of the stabilizer cylinders 21 is supported rotatably vertically at corresponding one of the left and right sides of the rear portion of the body frame 5 .
- the other end of each of the stabilizer cylinders 21 is supported by the other end of corresponding one of the stabilizers 20 .
- the boom bracket 22 is a main structure of the backhoe 4 .
- the front end of the boom bracket 22 is supported rotatably laterally at the rear end of the body frame 5 .
- the swing cylinders 23 are hydraulic cylinders which can be controlled to expand and contract by the backhoe operation device 13 .
- the swing cylinders 23 are provided respectively at the left and right sides of the body frame 5 and the boom bracket 22 .
- One of ends of each of the swing cylinders 23 is supported rotatably laterally at the rear end of the body frame 5 .
- the other end of each of the swing cylinders 23 is supported rotatably laterally at the front end of the boom bracket 22 .
- the boom 24 is a main structure of the backhoe 4 .
- One of ends of the boom 24 is supported rotatably vertically at the rear end of the boom bracket 22 .
- the boom cylinder 25 is a hydraulic cylinder which can be controlled to expand and contract by the backhoe operation device 13 .
- One of ends of the boom cylinder 25 is supported rotatably vertically on upper portion of the rear end of the boom bracket 22 .
- the other end of the boom cylinder 25 is supported rotatably vertically on the middle portion of the boom 24 .
- the arm 26 is a main structure of the backhoe 4 .
- One of ends of the arm 26 is supported rotatably vertically at the other end of the boom 24 .
- the arm cylinder 27 is a hydraulic cylinder which can be controlled to expand and contract by the backhoe operation device 13 .
- One of ends of the arm cylinder 27 is supported rotatably vertically on the middle portion of the boom 24 .
- the other end of the arm cylinder 27 is supported rotatably vertically at one of ends of the arm 26 .
- the bucket 28 is a member loaded with the earth and sand. One of ends of the bucket 28 is supported rotatably vertically at the other end of the arm 26 .
- the bucket cylinder 29 is a hydraulic cylinder which can be controlled to expand and contract by the backhoe operation device 13 .
- One of ends of the bucket cylinder 29 is supported rotatably vertically at the middle portion of the arm 26 .
- the other end of the bucket cylinder 29 is supported rotatably vertically at the bucket 28 .
- the boom bracket 22 By expanding and contracting the swing cylinders 23 , the boom bracket 22 can be rotated laterally. By expanding and contracting the boom cylinder 25 , the boom 24 can be rotated vertically. By expanding and contracting the arm cylinder 27 , the arm 26 can be rotated vertically about the boom 24 . By expanding and contracting the bucket cylinder 29 , the bucket 28 can be rotated vertically about the arm 26 . By combining the rotational action of the boom bracket 22 , the boom 24 , the arm 26 and the bucket 28 , the working vehicle 1 performs the excavation work of earth and sand.
- the hydraulic circuit 100 is provided in the working vehicle 1 .
- the hydraulic circuit 100 mainly has a HST section 110 , a reservoir tank 120 , a hydraulic pump section 130 , a power steering valve section 140 , a loader control valve 200 and a backhoe control valve 150 .
- the HST section 110 changes the working vehicle 1 in speed with the power of the engine 6 .
- the reservoir tank 120 is an embodiment of a tank according to the present invention and is a container in which pressure oil used in the hydraulic circuit 100 is reserved.
- a transmission casing provided in the working vehicle 1 may serve as the reservoir tank 120 .
- the hydraulic pump section 130 pressingly sends pressure oil with the power of the engine 6 .
- the hydraulic pump section 130 has a port 131 which is an opening through which pipes are connected.
- the hydraulic pump section 130 has discharge ports 132 , 133 and 134 through which pressure oil is discharged respectively by independent hydraulic pumps.
- a pipe 121 connects the reservoir tank 120 to the port 131 of the hydraulic pump section 130 .
- the hydraulic pump section 130 sucks pressure oil in the reservoir tank 120 through the pipe 121 and the port 131 and discharge the pressure oil through the discharge ports 132 , 133 and 134 .
- the power steering valve section 140 controls action of a steering cylinder 141 which controls the steering of the front wheels 8 .
- the power steering valve section 140 controls expand and contract of the steering cylinder 141 corresponding to the operation of the steering wheel 11 .
- the power steering valve section 140 has a port 142 which is an opening through which pipes are connected and the like.
- a pipe 135 connects the discharge port 134 of the hydraulic pump section 130 to the port 142 of the power steering valve section 140 .
- the power steering valve section 140 controls the action of the steering cylinder 141 with the pressure oil supplied through the discharge port 134 and the pipe 135 .
- the loader control valve 200 controls the action of the bucket lift cylinders 17 and the dump cylinders 18 .
- the loader control valve 200 has a pump port 251 , a tank port 252 , a carry-over port 253 , dump cylinder ports 254 and 255 , bucket lift cylinder ports 256 and 257 , ports 258 and 259 , PTO ports 260 and 261 , and the like which are openings through which pipes are connected.
- a pipe 136 connects the discharge port 133 of the hydraulic pump section 130 to the pump port 251 of the loader control valve 200 .
- a pipe 137 connects the discharge port 132 of the hydraulic pump section 130 to the port 258 of the loader control valve 200 .
- a pipe 262 connects the tank port 252 of the loader control valve 200 to the reservoir tank 120 .
- the backhoe control valve 150 controls the action of the stabilizer cylinders 21 , the swing cylinders 23 , the boom cylinder 25 , the arm cylinder 27 and the bucket cylinder 29 .
- the backhoe control valve 150 has ports 151 and 152 and the like which are openings through which pipes are connected.
- a pipe 263 connects the carry-over port 253 of the loader control valve 200 to the port 151 of the backhoe control valve 150 .
- a pipe 264 connects the port 259 of the loader control valve 200 to the port 152 of the backhoe control valve 150 .
- the backhoe control valve 150 controls the action of the stabilizer cylinders 21 , the swing cylinders 23 and the arm cylinder 27 with the pressure oil supplied through the pipe 263 and the port 151 .
- the backhoe control valve 150 controls the action of the stabilizer cylinders 21 , the bucket cylinder 29 and the boom cylinder 25 with the pressure oil supplied through the pipe 264 and the port 152 .
- the backhoe control valve 150 is provided at the downstream of the loader control valve 200 .
- the present invention is not limited thereto.
- a control valve or the like may alternatively be provided so as to switch the action of the lift cylinder which moves vertically the mounted working machine. It may alternatively be constructed that any control valve or the like is not provided.
- the loader control valve 200 mainly has a dump cylinder switching valve 210 , a bucket lift cylinder switching valve 220 , a mode switching valve 230 and a PTO switching valve 240 .
- the dump cylinder switching valve 210 is arranged between the pump port 251 and the dump cylinders 18 and switches the flow route of pressure oil pressingly sent to the dump cylinders 18 so as to switch the action of the dump cylinders 18 .
- the dump cylinder switching valve 210 has six ports and three positions (positions A, B and C). The position of the dump cylinder switching valve 210 can be switched by operating a loader operation lever 310 provided in the loader operation device 300 .
- An oil passage 270 connects the pump port 251 to the dump cylinder switching valve 210 .
- An oil passage 271 connects the oil passage 270 to an oil passage 272 .
- a release valve 271 a is provided at the middle portion of the oil passage 271 .
- the oil passage 272 is connected to the tank port 252 .
- An oil passage 273 connects the dump cylinder switching valve 210 to a middle portion of an oil passage 274 .
- the oil passage 274 connects the dump cylinder port 254 to the oil passage 272 .
- An anti-void release valve 274 a is provided at the middle portion of the oil passage 274 in the vicinity of the connection part of the oil passage 274 and the oil passage 272 .
- An oil passage 275 connects the dump cylinder switching valve 210 to a middle portion of an oil passage 276 .
- An oil passage 276 connects the dump cylinder port 255 to the oil passage 272 .
- An anti-void release valve 276 a is provided at the middle portion of the oil passage 276 in the vicinity of the connection part of the oil passage 276 and the oil passage 272 .
- a pipe 265 connects the dump cylinder port 254 to bottom chambers of the dump cylinders 18 .
- a pipe 266 connects the dump cylinder port 255 to rod chambers of the dump cylinders 18 .
- the pressure oil discharged from the discharge port 133 (see FIG. 2 ) is pressingly sent through the pipe 136 , the pump port 251 and the oil passage 270 to the dump cylinder switching valve 210 .
- the dump cylinder switching valve 210 By switching the dump cylinder switching valve 210 to the position C, the pressure oil is pressingly sent through the oil passage 273 , the oil passage 274 , the dump cylinder port 254 and the pipe 265 to the bottom chambers of the dump cylinders 18 . Accordingly, the dump cylinders 18 can be expanded.
- the dump cylinder switching valve 210 By switching the dump cylinder switching valve 210 to the position B, the pressure oil is pressingly sent through the oil passage 275 , the oil passage 276 , the dump cylinder port 255 and the pipe 266 to the rod chambers of the dump cylinders 18 . Accordingly, the dump cylinders 18 can be contracted.
- the dump cylinders 18 can be expanded and contracted. Accordingly, the loader bucket 16 can be rotated vertically about the bucket lift arms 15 .
- the bucket lift cylinder switching valve 220 is arranged between the dump cylinder switching valve 210 and the bucket lift cylinders 17 and switches the flow route of pressure oil pressingly sent to the bucket lift cylinders 17 so as to switch the action of the bucket lift cylinders 17 .
- the bucket lift cylinder switching valve 220 has six ports and four positions (positions D, E, F and G). The position of the bucket lift cylinder switching valve 220 can be switched by operating the loader operation lever 310 provided in the loader operation device 300 .
- An oil passage 277 connects the dump cylinder switching valve 210 to the bucket lift cylinder switching valve 220 .
- An oil passage 278 connects the bucket lift cylinder switching valve 220 to a middle portion of an oil passage 279 .
- the oil passage 279 connects the bucket lift cylinder port 256 to the oil passage 272 .
- a check valve 279 a is provided at the middle portion of the oil passage 279 in the vicinity of the connection part of the oil passage 279 and the oil passage 272 .
- An oil passage 280 connects the bucket lift cylinder switching valve 220 to the bucket lift cylinder port 257 .
- a pipe 267 connects the bucket lift cylinder port 256 to rod chambers of the bucket lift cylinders 17 .
- a pipe 268 connects the bucket lift cylinder port 257 to bottom chambers of the bucket lift cylinders 17 .
- the pressure oil is pressingly sent through the oil passage 280 , the bucket lift cylinder port 257 and the pipe 268 to the bottom chambers of the bucket lift cylinders 17 . Accordingly, the bottom chambers of the bucket lift cylinders 17 can be expanded.
- the pressure oil is pressingly sent through the oil passage 278 , the oil passage 279 , the bucket lift cylinder port 256 and the pipe 267 to the rod chambers of the bucket lift cylinders 17 . Accordingly, the bucket lift cylinders 17 can be contracted.
- the bucket lift cylinder switching valve 220 by switching the bucket lift cylinder switching valve 220 , the bucket lift cylinders 17 can be expanded and contracted. Accordingly, the bucket lift arms 15 can be moved vertically.
- the mode switching valve 230 is arranged between the bucket lift cylinder switching valve 220 and the carry-over port 253 and switches the flow route of pressure oil.
- the mode switching valve 230 is a directional control valve having five ports, i.e. ports 230 a and 230 b of the primary side and ports 230 c , 230 d and 230 e of the secondary side, and three positions.
- the mode switching valve 230 can be switched among a “working position H” in which the port 230 a is communicated with the port 230 c , the port 230 d is communicated with the port 230 e , and the port 230 b is blocked, a “return position J” in which the port 230 a , the port 230 b , the port 230 c , the port 230 d and the port 230 e are communicated with each other, and a “confluence position K” in which the port 230 a is communicated with the port 230 c and the port 230 d and the port 230 b is communicated with the port 230 e.
- the position of the mode switching valve 230 can be switched by operating a mode switching lever 340 provided in the loader operation device 300 .
- the mode switching valve 230 has two springs 231 and a detent mechanism 232 .
- the springs 231 hold the position of the mode switching valve 230 at the working position H.
- the mode switching valve 230 has the springs 231 in this embodiment, the present invention is not limited thereto. It may alternatively be constructed that the mode switching valve 230 does not have the springs 231 .
- the detent mechanism 232 holds the position of the mode switching valve 230 at the return position J or the confluence position K.
- the detent mechanism 232 holds the position of the mode switching valve 230 at corresponding one of the return position J and the confluence position K.
- An oil passage 281 connects the bucket lift cylinder switching valve 220 to the port 230 a of the mode switching valve 230 .
- An oil passage 282 connects the port 230 b of the mode switching valve 230 to the oil passage 272 (in its turn the reservoir tank 120 ).
- An oil passage 283 connects the port 230 d of the mode switching valve 230 to the port 258 (in its turn the discharge port 132 of the hydraulic pump).
- An oil passage 284 connects the port 230 e of the mode switching valve 230 to a middle portion of an oil passage 285 (in its turn the port 152 of the backhoe control valve 150 ).
- the oil passage 285 connects the oil passage 272 to the port 259 .
- An anti-void release valve 285 a is provided at the middle portion of the oil passage 285 in the vicinity of the connection part of the oil passage 285 and the oil passage 272 .
- the PTO switching valve 240 is arranged between the mode switching valve 230 and the carry-over port 253 and switches the flow route of pressure oil sent to the PTO ports 260 and 261 .
- the PTO switching valve 240 is a directional control valve having six ports, i.e. ports 240 a , 240 b and 240 c of the primary side and ports 240 d , 240 e and 240 f of the secondary side, and four positions.
- the PTO switching valve 240 can be switched among a “position L” in which the port 240 a is communicated with the port 240 d and the ports 240 b , 240 c , 240 e and 240 f are blocked, a “position M” in which the port 240 b is communicated with the port 240 f , the port 240 c is communicated with the port 240 e and the ports 240 a and 240 d are blocked, a “position N” in which the port 240 b is communicated with the port 240 e , the port 240 c is communicated with the port 240 f and the ports 240 a and 240 d are blocked, and a “continuous position P” in which the port 240 b is communicated with the port 240 e , the port 240 c is communicated with the port 240 f and the ports 240 a and 240 d are blocked.
- the PTO switching valve 240 can be switched by operating a PTO switching lever 360 provided in the loader operation device 300 .
- the PTO switching valve 240 has two springs 241 and a detent mechanism 242 .
- the springs 241 hold the position of the PTO switching valve 240 at the position L.
- the detent mechanism 242 holds the position of the PTO switching valve 240 at the continuous position P.
- the detent mechanism 242 holds the position of the PTO switching valve 240 at the continuous position P.
- An oil passage 286 connects the port 230 c of the mode switching valve 230 to the port 240 a of the PTO switching valve 240 .
- An oil passage 287 connects the middle portion of the oil passage 286 to the port 240 b of the PTO switching valve 240 .
- a check valve 287 a is provided at the middle portion of the oil passage 287 .
- An oil passage 288 connects the port 240 c of the PTO switching valve 240 to the oil passage 272 .
- An oil passage 289 connects the port 240 d of the PTO switching valve 240 to the carry-over port 253 .
- An oil passage 290 connects the port 240 e of the PTO switching valve 240 to an oil passage 291 .
- the oil passage 291 connects the PTO port 260 to the oil passage 272 .
- a plug 291 a is provided at the middle portion of the oil passage 291 in the vicinity of the connection part of the oil passage 291 and the oil passage 272 . If necessary, instead of the plug 291 a , a release valve or the like may alternatively be interposed.
- An oil passage 292 connects the port 240 f of the PTO switching valve 240 to a middle portion of an oil passage 293 .
- the oil passage 293 connects the PTO port 261 to the oil passage 272 .
- a plug 293 a is provided at the middle portion of the oil passage 293 in the vicinity of the connection part of the oil passage 293 and the oil passage 272 . If necessary, instead of the plug 293 a , a release valve or the like may alternatively be interposed.
- the mode switching lever 340 and the PTO switching lever 360 have an interlock mechanism 400 .
- the interlock mechanism 400 restricts the action of the mode switching lever 340 (in its turn, the action of the mode switching valve 230 ) based on the position of the PTO switching lever 360 (in its turn, the position of the PTO switching valve 240 ). More concretely, the interlock mechanism 400 restricts the action of the mode switching lever 340 so that the mode switching valve 230 can be switched to the confluence position K only in the case that the PTO switching valve 240 is at the continuous position P.
- the mode switching valve 230 is switched to the working position H.
- the PTO switching valve 240 is not operated, whereby the PTO switching valve 240 is held at the position L by the springs 241 .
- the pressure oil discharged from the discharge port 133 is pressingly sent through the pipe 136 , the pump port 251 , the oil passage 270 , the dump cylinder switching valve 210 , the oil passage 277 , the bucket lift cylinder switching valve 220 , the oil passage 281 , the mode switching valve 230 , the oil passage 286 , the PTO switching valve 240 , the oil passage 289 , the carry-over port 253 and the pipe 263 to the backhoe control valve 150 (see FIG. 2 ).
- the pressure oil discharged from the discharge port 132 (see FIG. 2 ) is pressingly sent through the pipe 137 , the port 258 , the oil passage 283 , the mode switching valve 230 , the oil passage 284 , the oil passage 285 , the port 259 and the pipe 264 to the backhoe control valve 150 (see FIG. 2 ).
- the pressure oil discharged from the discharge ports 132 and 133 are pressingly sent to the backhoe control valve 150 .
- the backhoe 4 is driven with the pressure oil pressingly sent.
- the mode switching valve 230 is switched to the working position H.
- the pressure oil discharged from the discharge port 133 (see FIG. 2 ) is pressingly sent through the pipe 136 , the pump port 251 , the oil passage 270 , the dump cylinder switching valve 210 , the oil passage 277 , the bucket lift cylinder switching valve 220 , the oil passage 281 , the mode switching valve 230 , and the oil passages 286 and 287 to the PTO switching valve 240 .
- the PTO switching lever 360 so as to switch the PTO switching valve 240 to the position M or N, the pressure oil pressingly sent can be extracted through the PTO port 260 or the PTO port 261 .
- the working machine is driven with the extracted pressure oil.
- the mode switching valve 230 is switched to the return position J.
- the pressure oil discharged from the discharge port 133 (see FIG. 2 ) is pressingly sent through the pipe 136 , the pump port 251 and the oil passage 270 to the dump cylinder switching valve 210 .
- the loader 3 is operated with the pressure oil pressingly sent.
- the pressure oil discharged from the discharge port 133 and passing through the dump cylinder switching valve 210 and the bucket lift cylinder switching valve 220 is pressingly sent through the oil passage 281 to the mode switching valve 230 .
- the pressure oil discharged from the discharge port 132 (see FIG. 2 ) is pressingly sent through the pipe 137 , the port 258 and the oil passage 283 to the mode switching valve 230 .
- the pressure oil discharged from the discharge ports 132 and 133 and pressingly sent to the mode switching valve 230 is returned through the oil passage 282 , the oil passage 272 , the tank port 252 and the pipe 262 to the reservoir tank 120 (see FIG. 2 ).
- the mode switching valve 230 by switching the mode switching valve 230 to the return position J, the pressure oil discharged from the discharge port 132 can be returned to the reservoir tank 120 through the short route. Accordingly, in the case that any work is not performed with the backhoe 4 , pressure loss caused by the pipes can be reduced, whereby the engine power can be used effectively.
- the PTO switching valve 240 is switched to the continuous position P. Then, the restriction of action of the mode switching valve 230 by the interlock mechanism 400 is released. Subsequently, the mode switching valve 230 is switched to the confluence position K.
- the pressure oil discharged from the discharge port 133 (see FIG. 2 ) is pressingly sent through the pipe 136 , the pump port 251 , the oil passage 270 , the dump cylinder switching valve 210 , the oil passage 277 , the bucket lift cylinder switching valve 220 , and the oil passage 281 to the mode switching valve 230 .
- the pressure oil discharged from the discharge port 132 (see FIG. 2 ) is pressingly sent through the pipe 137 , the port 258 and the oil passage 283 to the mode switching valve 230 .
- the pressure oil discharged from the discharge ports 132 and 133 and pressingly sent to the mode switching valve 230 is combined in the mode switching valve 230 .
- the combined pressure oil is pressingly sent through the oil passages 286 and 287 , the interlock mechanism 400 , the oil passage 290 , the oil passage 291 and the PTO port 260 to the connected working machine.
- the working vehicle 1 in this embodiment comprises
- the PTO switching valve 240 arranged downstream the mode switching valve 230 and switched so as to send pressingly the pressure oil to the PTO ports 260 and 261 ,
- the pressure oil discharged from the discharge ports 132 and 133 can be combined.
- a working machine which requires too large flow rate to be driven by the pressure oil discharged from one of the discharge ports 132 and 133 can be driven. Accordingly, a working machine requiring large flow rate such as a skid steer can be driven on the working vehicle 1 .
- the mode switching valve 230 is provided integrally in the loader control valve 200 having the PTO switching valve 240 .
- the present invention is not limited to this construction, and the mode switching valve 230 may alternatively be constructed independently of the loader control valve 200 .
- the piping construction of the hydraulic circuit 100 provided in the working vehicle 1 can be simplified. Concretely, a three way joint required at a connection part 537 a between a pipe 537 and a pipe 564 shown in FIG. 14 can be made unnecessary. Accordingly, the piping construction of the hydraulic circuit 100 can be simplified so as to reduce the part number and reduce the number of assembly processes.
- the mode switching valve 230 can be switched among the confluence position K, the return position J at which the pressure oil pressingly sent by the two hydraulic pumps is returned to the reservoir tank 120 , and the working position H at which the pressure oil pressingly sent by the two hydraulic pumps is pressingly sent to the backhoe control valve 150 arranged at the downstream side without combining the pressure oil.
- the mode switching valve 230 by switching the mode switching valve 230 to the return position J, the pressure oil can be returned to the reservoir tank 120 with the short route. Accordingly, pressure loss caused by the pipes and the like in the hydraulic circuit 100 can be reduced. Since the confluence position K, the return position J and the working position H are provided in the same valve, it is not necessary to secure separately a space in which the valve is arranged, whereby the space is saved. Furthermore, by providing the positions in the same valve, the part number and cost can be reduced.
- the PTO switching valve 240 has
- the interlock mechanism 400 which makes the mode switching valve 230 able to be switched to the confluence position K only in the case that the PTO switching valve 240 is switched to the continuous position P.
- the safety of the working vehicle 1 can be improved.
- the pressure oil combined in the mode switching valve 230 is pressingly sent through the oil passage 286 , the PTO switching valve 240 , the oil passage 289 , the carry-over port 253 , the pipe 263 and the port 151 to the backhoe control valve 150 .
- any pressure oil is not supplied from the port 152 to the backhoe control valve 150 .
- the stabilizer cylinders 21 , the swing cylinders 23 and the arm cylinder 27 shown in FIG. 2 are operated at high speed by the pressure oil supplied from the port 151 , and the state is realized that the stabilizer cylinders 21 , the bucket cylinder 29 and the boom cylinder 25 are not operated at all (hereinafter, the state is simply referred to as “wrong operation state”).
- the backhoe 4 When the backhoe 4 is operated at the wrong operation state, the backhoe 4 may act against operator's will. The action against the operator's will may cause defects such as instability of posture of the working vehicle 1 .
- the mode switching valve 230 can be switched to the confluence position K only in the case that the PTO switching valve 240 is at the continuous position P, whereby the pressure oil combined in the mode switching valve 230 is prevented from being supplied to the backhoe control valve 150 . Accordingly, the wrong operation state as mentioned above can be prevented so as to improve the safety of the working vehicle 1 .
- the loader operation device 300 mainly has the loader control valve 200 , the loader operation lever 310 , a dump link mechanism 320 , a bucket link mechanism 330 , the mode switching lever 340 , a mode switching link mechanism 350 , the PTO switching lever 360 , a PTO link mechanism 370 , a limit switch 380 and a throttle lever 390 .
- the loader control valve 200 controls the action of the bucket lift cylinders 17 , the dump cylinders 18 and the like.
- the loader control valve 200 is provided at the right side of the seat 12 .
- the loader control valve 200 mainly has the dump cylinder switching valve 210 , the bucket lift cylinder switching valve 220 , the mode switching valve 230 and the PTO switching valve 240 .
- the loader operation lever 310 switches the positions of the dump cylinder switching valve 210 and the bucket lift cylinder switching valve 220 .
- the loader operation lever 310 is arranged above the loader control valve 200 .
- the dump link mechanism 320 connects the loader operation lever 310 to the dump cylinder switching valve 210 .
- the position of the dump cylinder switching valve 210 can be switched.
- the bucket link mechanism 330 connects the loader operation lever 310 to the bucket lift cylinder switching valve 220 .
- the mode switching lever 340 switches the position of the mode switching valve 230 .
- the mode switching lever 340 is arranged above the loader control valve 200 and behind the loader operation lever 310 .
- the mode switching lever 340 mainly has a boss part 341 , a grip part 342 , an arm part 343 and a cam part 344 .
- the boss part 341 is substantially cylindrical.
- the boss part 341 is rotatably supported by a pivot shaft 345 whose axial direction is substantially the same as the lateral direction.
- the grip part 342 is substantially cylindrical. One of ends of the grip part 342 is fixed to the outer peripheral surface of the boss part 341 . The other end of the grip part 342 is extended rearward and upward. A grip 342 a is provided at the other end of the grip part 342 .
- the arm part 343 is substantially rectangular plate-like. One of ends of the arm part 343 is fixed to the outer peripheral surface of the boss part 341 . The other end of the arm part 343 is extended forward.
- the cam part 344 is substantially plate-like. One of ends of the cam part 344 is fixed to the outer peripheral surface of the boss part 341 . The other end of the cam part 344 is extended rearward, and the tip thereof is formed substantially triangularly.
- the mode switching link mechanism 350 connects the other end of the arm part 343 to the mode switching valve 230 .
- an operator grips the grip part 342 (the grip 342 a ) of the mode switching lever 340 and operates longitudinally the mode switching lever 340 .
- the boss part 341 centering on the pivot shaft 345
- the other end of the arm part 343 is rotated vertically. Accordingly, the position of the mode switching valve 230 is switched via the mode switching link mechanism 350 .
- the PTO switching lever 360 switches the position of the PTO switching valve 240 .
- the PTO switching lever 360 is arranged above the loader control valve 200 and behind the loader operation lever 310 .
- the PTO switching lever 360 mainly has a boss part 361 , a grip part 362 , an arm part 363 , a cam part 364 and a touching part 365 .
- the boss part 361 is substantially cylindrical.
- the boss part 361 is rotatably supported by a pivot shaft 366 whose axial direction is substantially the same as the lateral direction.
- the boss part 361 is arranged below and behind the boss part 341 of the mode switching lever 340 .
- the grip part 362 is substantially cylindrical. One of ends of the grip part 362 is fixed to the outer peripheral surface of the boss part 361 . The other end of the grip part 362 is extended upward. A grip 362 a is provided at the other end of the grip part 362 .
- the arm part 363 is substantially rectangular plate-like. One of ends of the arm part 363 is fixed to the outer peripheral surface of the boss part 361 . The other end of the arm part 363 is extended forward.
- the cam part 364 is substantially plate-like. One of ends of the cam part 364 is fixed to the outer peripheral surface of the boss part 361 . The other end of the cam part 364 is extended forward.
- the cam part 364 of the PTO switching lever 360 is arranged substantially the same plane position as the cam part 344 of the mode switching lever 340 in the lateral direction.
- the touching part 365 is substantially plate-like. One of ends of the touching part 365 is fixed to the outer peripheral surface of the boss part 361 . The other end of the touching part 365 is extended rearward.
- the PTO link mechanism 370 connects the other end of the arm part 363 to the PTO switching valve 240 .
- an operator grips the grip part 362 (the grip 362 a ) of the PTO switching lever 360 and operates longitudinally the PTO switching lever 360 .
- the boss part 361 centering on the pivot shaft 366 By rotating the boss part 361 centering on the pivot shaft 366 , the other end of the arm part 363 is rotated vertically. Accordingly, the position of the PTO switching valve 240 is switched via the PTO link mechanism 370 .
- the limit switch 380 is an embodiment of a starting inhibition means according to the present invention, and is a switch whose contact point is engaged/disengaged corresponding to whether an operation chip 381 is pressed or not.
- the limit switch 380 is arranged below and behind the boss part 361 of the PTO switching lever 360 and below the touching part 365 of the PTO switching lever 360 .
- the limit switch 380 is arranged at the position at which the operation chip 381 of the limit switch 380 is pressed by the touching part 365 of the PTO switching lever 360 .
- the throttle lever 390 sets the rotational speed of the engine 6 of the working vehicle 1 (hereinafter, simply referred to as “engine rotational speed”).
- the throttle lever 390 is arranged behind the PTO switching lever 360 .
- the throttle lever 390 is rotatable longitudinally centering on the lower end thereof By operating rotationally the throttle lever 390 , the engine rotational speed can be set. Concretely, by rotating forward the throttle lever 390 , the engine rotational speed can be increased. By rotating rearward the throttle lever 390 , the engine rotational speed can be reduced.
- the interlock mechanism 400 has the cam part 344 of the mode switching lever 340 and the cam part 364 of the PTO switching lever 360 .
- the position of the mode switching lever 340 in the case that the mode switching valve 230 is at the working position H is defined as a lever position Q
- the position of the mode switching lever 340 in the case that the mode switching valve 230 is at the return position J is defined as a lever position R
- the position of the mode switching lever 340 in the case that the mode switching valve 230 is at the confluence position K is defined as a lever position S.
- the positions of the PTO switching lever 360 in the case that the PTO switching valve 240 is at the positions L, M and N and the continuous position P are respectively defined as lever positions T, U, V and W.
- FIGS. 5 to 9 together with the reference letters of the lever positions, the reference letters of the positions of the mode switching valve 230 and the PTO switching valve 240 corresponding to the lever positions are shown in parentheses.
- the mode switching lever 340 can be switched to the lever position Q or the lever position R.
- the other end of the cam part 364 of the PTO switching lever 360 is positioned in the rotational locus of the cam part 344 of the mode switching lever 340 while directing upward so as to restrict the rotational range of the mode switching lever 340 , but is not within the rotational range of the mode switching lever 340 to be switched to the lever position Q or the lever position R and does not affect the rotation.
- a lower surface 344 a of the cam part 344 of the mode switching lever 340 touches an upper surface 364 a of the cam part 364 of the PTO switching lever 360 .
- the cam part 364 of the PTO switching lever 360 restricts the rotation of the mode switching lever 340 toward the lever position S. Accordingly, the mode switching lever 340 cannot be switched to the lever position S. Namely, the mode switching valve 230 cannot be switched to the confluence position K, whereby the pressure oil discharged from one of the discharge ports 132 and 133 is not combined.
- the rotation of the mode switching lever 340 toward the lever position S is also restricted. Accordingly, the mode switching lever 340 cannot be switched to the lever position S. Namely, the mode switching valve 230 cannot be switched to the confluence position K.
- the operation chip 381 of the limit switch 380 is pressed by the touching part 365 of the PTO switching lever 360 .
- the limit switch 380 is provided which inhibits the starting of the engine 6 in the case that the PTO switching valve 240 is switched to the continuous position P.
- the engine 6 in the case that the PTO switching valve 240 is switched to the continuous position P, the engine 6 cannot be started. Namely, the working machine connected to the PTO ports 260 and 261 is prevented from being started driving simultaneously to the starting of the engine 6 . Accordingly, at the time of maintenance of the working machine or the like, the working machine is prevented from being driven simultaneously to the starting of the engine 6 , whereby the safety of maintenance work of the working machine and the like is improved.
- the starting inhibition means is constructed by the limit switch 380 , but the present invention is not limited thereto.
- the starting inhibition means only must be constructed so as to detect that the PTO switching valve 240 is switched to the continuous position P and inhibit the starting of the engine 6 .
- the lower surface 344 a of the cam part 344 of the mode switching lever 340 does not touch the upper surface 364 a of the cam part 364 of the PTO switching lever 360 .
- the cam part 364 at the lever position W is not within the rotational range of the cam part 344 of the mode switching lever 340 , and the restriction of the rotation of the mode switching lever 340 toward the lever position S by the cam part 364 of the PTO switching lever 360 is canceled.
- the mode switching lever 340 can be switched to the lever position S.
- the mode switching valve 230 can be switched to the confluence position K only in the case that the PTO switching valve 240 is at the continuous position P.
- the pressure oil combined in the mode switching valve 230 is prevented from being pressingly sent to the port 151 of the backhoe control valve 150 . Accordingly, the wrong operation state of the backhoe 4 can be prevented so as to improve the safety of the working vehicle 1 .
- the vertex 364 b of the cam part 364 of the PTO switching lever 360 pushes the mode switching lever 340 toward the lever position Q while sliding on the lower rear surface 344 b of the cam part 344 and touches a vertex 344 c of the cam part 344 of the mode switching lever 340 .
- the mode switching lever 340 is rotated to a position for predetermined angle toward the lever position R from the lever position Q (lever position Qa). Namely, the mode switching valve 230 is moved across the working position H toward the return position J for predetermined dimension.
- the mode switching valve 230 is returned to the working position H and held at the position by the springs 231 .
- the mode switching lever 340 is returned to the lever position Q and held at the position.
- the mode switching lever 340 can be returned simultaneously from the lever position S to the lever position Q. Namely, by operating the PTO switching lever 360 , the mode switching valve 230 can be switched to the working position H.
- the mode switching valve 230 is switched from the confluence position K to one of the other positions (the working position H or the return position J).
- the wrong operation state of the backhoe 4 can be prevented so as to improve the safety.
- the mode switching valve 230 is moved to the position across the position other than the confluence position K (the working position H or the return position J) for the predetermined dimension.
- the mode switching valve 230 can be switched certainly to the working position H.
- the predetermined angle and the predetermined dimension are set so that the mode switching valve 230 can be returned to the working position H by the springs 231 .
- the loader operation device 300 may alternatively has a throttle lever restriction mechanism 450 which is an embodiment of an engine rotational speed restriction means according to the present invention.
- the throttle lever restriction mechanism 450 restricts the rotatable range of the throttle lever 390 based on the position of the mode switching lever 340 .
- the throttle lever restriction mechanism 450 mainly has an intermediate link member 451 , mode switching lever link members 452 and 453 , and throttle lever link members 454 and 455 .
- the intermediate link member 451 is substantially triangular and plate-like.
- the lower end of the intermediate link member 451 is supported rotatably longitudinally by a pivot shaft 451 a.
- the mode switching lever link member 452 is substantially rectangular plate-like. One of ends of the mode switching lever link member 452 is supported rotatably vertically by a pivot shaft 452 a at the upper end of the intermediate link member 451 .
- the mode switching lever link member 453 is substantially rectangular plate-like. One of ends of the mode switching lever link member 453 is fixed to the other end of the mode switching lever link member 452 . A through hole 453 a is formed at the other end of the mode switching lever link member 453 and penetrates it. The operator grips the grip part 342 of the mode switching lever 340 is inserted into the through hole 453 a.
- the throttle lever link member 454 is substantially rectangular plate-like. One of ends of the throttle lever link member 454 is supported rotatably vertically by a pivot shaft 454 a at the vertical middle portion of the intermediate link member 451 .
- the throttle lever link member 455 is substantially rectangular plate-like. One of ends of the throttle lever link member 455 is fixed to the other end of the throttle lever link member 454 . A through hole 455 a is formed at the other end of the throttle lever link member 455 and penetrates it. The lengthwise direction of the through hole 455 a is in agreement with the longitudinal direction. The throttle lever 390 is inserted into the through hole 455 a.
- the throttle lever 390 can be rotated longitudinally from the position at which the engine rotational speed is the minimum to the position at which the engine rotational speed is the maximum (hereinafter, simply referred to as “lever position X”).
- the through hole 455 a of the throttle lever link member 455 is formed so as not to touch the throttle lever 390 when the throttle lever 390 is rotated in the case that the mode switching lever 340 is at one of the positions except the lever position S.
- the mode switching lever link members 452 and 453 are moved rearward interlockingly with the rotation of the mode switching lever 340 .
- the mode switching lever link members 452 and 453 By the movement of the mode switching lever link members 452 and 453 , the upper end of the intermediate link member 451 is rotated rearward.
- the throttle lever link members 454 and 455 are moved rearward.
- the through hole 455 a of the throttle lever link member 455 is also moved rearward, whereby the forward rotation of the throttle lever 390 is restricted. Namely, in the case that the throttle lever 390 is at the lever position X, when the mode switching lever 340 is switched to the lever position S, the throttle lever 390 is rotated rearward for predetermined rotational angle by the throttle lever link member 455 .
- the throttle lever 390 when the throttle lever 390 is rotated forward, the throttle lever 390 touches the inner peripheral front end of the through hole 455 a of the throttle lever link member 455 , whereby the throttle lever 390 cannot be rotated to the lever position X. Accordingly, the engine rotational speed is restricted not more than a predetermined value.
- the predetermined value of the engine rotational speed is set previously for suppressing the temperature of pressure oil in the working vehicle 1 so as not to cause extraordinariness.
- the working vehicle 1 in this embodiment has the throttle lever restriction mechanism 450 which restricts the engine rotational speed not more than the predetermined rotational speed in the case that the mode switching valve 230 is switched to the confluence position K.
- the rotation of the throttle lever 390 can be restricted so as to restrict the engine rotational speed not more than the predetermined value.
- the discharge amount of pressure oil by the hydraulic pump provided in the hydraulic pump section 130 can be reduced. Accordingly, the rising of temperature of pressure oil in the case that the mode switching valve 230 is switched to the confluence position K is suppressed, whereby extraordinariness such as overheating can be prevented.
- the through hole 455 a formed in the throttle lever link member 455 is formed so as to restrict the rotation of the throttle lever 390 , that is, restrict the engine rotational speed not more than the predetermined value in the case that the mode switching lever 340 is at the lever position S.
- a throttle lever restriction mechanism 460 described below may alternatively be provided.
- the throttle lever restriction mechanism 460 has a link member 461 .
- the link member 461 is plate-like.
- a through hole 461 a is formed in one of ends of the link member 461 and penetrates it. The operator grips the grip part 342 of the mode switching lever 340 is inserted into the through hole 461 a.
- a through hole 461 b is formed in the other end of the link member 461 and penetrates it.
- the lengthwise direction of the through hole 461 b is in agreement with the longitudinal direction.
- the throttle lever 390 is inserted into the through hole 461 b.
- the throttle lever 390 can be rotated longitudinally from the position at which the engine rotational speed is the minimum to the position at which the engine rotational speed is the maximum (lever position X).
- the dimension of the through hole 461 b of the link member 461 is formed so as not to touch the throttle lever 390 when the throttle lever 390 is rotated in the case that the mode switching lever 340 is at one of the positions except the lever position S.
- the link member 461 When the mode switching lever 340 is switched to the lever position S, the link member 461 is moved rearward interlockingkly with the rotation of the mode switching lever 340 . In this case, the through hole 461 b of the link member 461 is also moved rearward, whereby the forward rotation of the throttle lever 390 is restricted. Namely, in the case that the throttle lever 390 is at the lever position X, when the mode switching lever 340 is switched to the lever position S, the throttle lever 390 is rotated rearward for predetermined rotational angle by the link member 461 .
- the throttle lever 390 when the throttle lever 390 is rotated forward, the throttle lever 390 touches the inner peripheral front end of the through hole 461 b of the link member 461 , whereby the throttle lever 390 cannot be rotated to the lever position X. Accordingly, the engine rotational speed is restricted not more than a predetermined value.
- a throttle lever restriction mechanism 470 described below may alternatively be provided.
- the throttle lever restriction mechanism 470 has a mode switching lever arm 471 , a throttle lever arm 472 , a cable 473 and the like.
- the mode switching lever arm 471 is substantially cylindrical. One of ends of the mode switching lever arm 471 is fixed to the outer peripheral surface of the boss part 341 . The other end of the mode switching lever arm 471 is extended downward.
- the throttle lever arm 472 is substantially cylindrical. One of ends of the throttle lever arm 472 is fixed to the lower end of the throttle lever 390 . The other end of the throttle lever arm 472 is extended downward.
- the cable 473 is string-like and connects the mode switching lever arm 471 to the throttle lever arm 472 .
- One of ends of the cable 473 is connected to the other end of the mode switching lever arm 471 .
- the other end of the cable 473 is connected to the other end of the throttle lever arm 472 .
- the throttle lever 390 can be rotated longitudinally from the position at which the engine rotational speed is the minimum to the position at which the engine rotational speed is the maximum (lever position X).
- the dimension (length) of the cable 473 is formed so as not to restrict the rotation of the throttle lever 390 when the throttle lever 390 is rotated in the case that the mode switching lever 340 is at one of the positions except the lever position S.
- the mode switching lever arm 471 When the mode switching lever 340 is switched to the lever position S, the mode switching lever arm 471 is rotated interlockingkly with the rotation of the mode switching lever 340 . By rotating the mode switching lever arm 471 , the other end of the throttle lever arm 472 is pulled forward via the cable 473 . Namely, in the case that the throttle lever 390 is at the lever position X, when the mode switching lever 340 is switched to the lever position S, the throttle lever 390 is rotated rearward for predetermined rotational angle by the cable 473 .
- the engine rotational speed restriction means according to the present invention is not limited to the construction such as the throttle lever restriction mechanisms 450 , 460 and 470 . Namely, it only must be constructed so that the engine rotational speed can be restricted not more than a predetermined value when the mode switching lever 340 is switched to the lever position S.
- the present invention can be employed for an art of a working vehicle having two or more hydraulic pumps.
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Abstract
Description
- The present invention relates to an art of a working vehicle having two or more hydraulic pumps.
- Conventionally, an art of a working vehicle having two or more hydraulic pumps is well known (for example, see the Patent Literature 1).
- A hydraulic circuit of the working vehicle has a
loader control valve 500 shown inFIG. 14 . - Pressure oil sent by one of the two hydraulic pumps (not shown) is supplied through a pipe 536 and a
pump port 551 to theloader control valve 500. By switching a dampingcylinder switching valve 510 and a bucket lifting cylinder switching valve 520, with the pressure oil sent by the one of the hydraulic pumps, the operation of two damping cylinders 518 and twobucket lifting cylinders 517 can be switched, in its turn operation of a loader (not shown) can be controlled. - By switching a
PTO switching valve 540, the pressure oil sent by the one of the hydraulic pumps can be extracted throughPTO ports - Furthermore, pressure oil sent by the other hydraulic pump (not shown) is supplied through
pipes loader control valve 500. With the pressure oil supplied by the other hydraulic pump and the pressure oil pressingly sent by the one of the hydraulic pumps through theloader control valve 500, acarryover port 553 and apipe 563 to the backhoe control valve, a backhoe (not shown) is driven. - Patent Literature 1: the Japanese Patent Laid Open Gazette 2006-249882
- However, it is disadvantageous that the pressure oil extracted through the PTO switching valve may be unable to drive a working machine requiring large flow rate. For example, in the case that the discharge amount of the pressure oil by the one of the hydraulic pumps is about 10 GPM (gallon/minute), a working machine requiring 17 GPM of pressure oil cannot be driven.
- The present invention is provided in consideration of the above problems, and the purpose of the present invention is to provide a working vehicle in which pressure oil pressingly sent by two hydraulic pumps can be combined and extracted.
- The above problems are solved by the following means according to the present invention.
- Namely, the present invention includes two or more hydraulic pumps independent of each other and pressingly sending pressure oil, a mode switching valve which can be switched to a confluence position at which the pressure oil pressingly sent by the two or more hydraulic pumps is combined, a PTO port at which the pressure oil is extracted, and a PTO switching valve arranged downstream the mode switching valve and switched so as to send pressingly the pressure oil to the PTO port.
- According to the present invention, the mode switching valve is provided integrally in a control valve having the PTO switching valve.
- According to the present invention, the mode switching valve can be switched among the confluence position, a return position at which the pressure oil pressingly sent by the two hydraulic pumps is returned to a tank, and a working position at which the pressure oil pressingly sent by the two hydraulic pumps is pressingly sent to the other control valves respectively arranged at the downstream sides without combining the pressure oil.
- According to the present invention, the PTO switching valve has a continuous position at which pressure oil is held to be able to be sent pressingly to the PTO port, and an interlock mechanism which makes the mode switching valve able to be switched to the confluence position only in the case that the PTO switching valve is switched to the continuous position.
- According to the present invention, the interlock mechanism is constructed so that, when the PTO switching valve is switched from the continuous position to the other position, the mode switching valve is switched from the confluence position to the other position.
- According to the present invention, the interlock mechanism is constructed so that, in the middle of switching of the PTO switching valve from the continuous position to the other position, the mode switching valve is moved to a position across the position other than the confluence position for a predetermined dimension.
- According to the present invention, a starting inhibition means is provided which inhibits starting of an engine in the case that the PTO switching valve is switched to the continuous position.
- According to the present invention, an engine rotational speed restriction means is provided which restricts the rotational speed of the engine not more than a predetermined rotational speed in the case that the mode switching valve is switched to the confluence position.
- The present invention constructed as the above brings the following effects.
- According to the present invention, the pressure oil pressingly sent by the hydraulic pumps independent of each other can be combined and the combined pressure oil can be extracted through the PTO port. Accordingly, a working machine requiring large flow rate can be driven.
- According to the present invention, any space is not required for arranging the mode switching valve, whereby the space can be saved. Simultaneously, any piping connecting the mode switching valve to the control valve is not required, whereby the part number and cost can be reduced.
- According to the present invention, by switching the mode switching valve to the return position, the pressure oil can be returned to the tank with the short route. Accordingly, pressure loss caused by the pipes and the like in the hydraulic circuit can be reduced. Since the confluence position, the return position and the working position are provided in the same valve, it is not necessary to secure separately a space in which the valve is arranged, whereby the space is saved. Furthermore, by providing the positions in the same valve, the part number and cost can be reduced.
- According to the present invention, the pressure oil pressingly sent by the two or more hydraulic pumps can be combined only in the case that the pressure oil is extracted from the PTO port regularly (continuously). Accordingly, the combined pressure oil is prevented from being pressingly sent from the port other than the PTO port so as to cause error of a working machine at the downstream side because of the large flow rate, thereby improving the safety of the working vehicle.
- According to the present invention, the pressure oil pressingly sent by the two or more hydraulic pumps can be combined only in the case that the pressure oil is extracted from the PTO port regularly (continuously). Only by switching the PTO switching valve from the continuous position, the combining of the pressure oil can be stopped.
- According to the present invention, the mode switching valve can be switched certainly to the position other than the confluence position.
- According to the present invention, the working machine connected to the PTO port is prevented from being driven simultaneously to the starting of the engine. Accordingly, the safety of the working machine can be improved.
- According to the present invention, in the case of combining the pressure oil pressingly sent by the two or more hydraulic pumps, the rising of temperature of the combined pressure oil K can be suppressed. Accordingly, extraordinariness such as overheating can be prevented.
- [
FIG. 1 ] It is a right side view of entire construction of a working vehicle according to an embodiment of the present invention. - [
FIG. 2 ] It is an entire schematic drawing of a hydraulic circuit provided in the working vehicle. - [
FIG. 3 ] It is a partially enlarged drawing of the hydraulic circuit. - [
FIG. 4 ] It is a left side view of a loader operation device. - [
FIG. 5 ] It is an enlarged left side view of the action mode of the loader operation device. - [
FIG. 6 ] It is an enlarged left side view of the action mode of the loader operation device. - [
FIG. 7 ] It is an enlarged left side view of the action mode of the loader operation device. - [
FIG. 8 ] It is an enlarged left side view of the action mode of the loader operation device. - [
FIG. 9 ] It is an enlarged left side view of the action mode of the loader operation device. - [
FIG. 10 ] It is a left side view of an engine rotational speed restriction means. - [
FIG. 11 ] It is an enlarged left side view of the action mode of the engine rotational speed restriction means. - [
FIG. 12 ] It is a left side view of another embodiment of the engine rotational speed restriction means. - [
FIG. 13 ] It is a left side view of another embodiment of the engine rotational speed restriction means. - [
FIG. 14 ] It is a drawing of a conventional hydraulic circuit. -
- 1 working vehicle
- 6 engine
- 3 loader
- 4 backhoe
- 120 reservoir tank
- 150 backhoe control valve
- 200 loader control valve
- 230 mode switching valve
- 240 PTO switching valve
- 260 PTO port
- 261 PTO port
- 344 cam part
- 364 cam part
- 380 limit switch
- 400 interlock mechanism
- 450 throttle lever restriction mechanism
- Next, explanation will be given on a working vehicle 1 which is an embodiment according to the present invention.
- As shown in
FIG. 1 , the working vehicle 1 performs conveyance work and excavation work of earth and sand and the like with a working device. The working vehicle 1 mainly has a traveling vehicle 2, aloader 3 and abackhoe 4. - The traveling vehicle 2 is a main body of the working vehicle 1. The traveling vehicle 2 mainly has a body frame 5, an
engine 6, abonnet 7, twofront wheels 8, tworear wheels 9 and an operation part 10. - The body frame 5 is a main structure of the traveling vehicle 2. The body frame 5 is a substantially box-like member formed from a plurality of plate members while the lengthwise direction thereof is in agreement with the longitudinal direction.
- The
engine 6 generates power for driving the working vehicle 1. Theengine 6 is provided in the front portion of the body frame 5. - The
bonnet 7 covers apparatuses such as theengine 6 provided in the traveling vehicle 2. Thebonnet 7 is provided in the front portion of the body frame 5. Thebonnet 7 is constructed so as to cover the apparatuses such as theengine 6 provided in the front portion of the body frame 5. - The
front wheels 8 support the body frame 5. Thefront wheels 8 are provided respectively at the left and right of the lower front portion of the body frame 5. Thefront wheels 8 are rotated by the power generated by theengine 6. - The
rear wheels 9 support the body frame 5. Therear wheels 9 are provided respectively at the left and right of the lower rear portion of the body frame 5. Therear wheels 9 are rotated by the power generated by theengine 6. - The operation part 10 is a position in which an operator operates the working vehicle 1. The operation part 10 is provided at the substantially longitudinal center of the body frame 5. The operation part 10 mainly has a
steering wheel 11, aseat 12, aloader operation device 300 and a backhoe operation device 13. - The
steering wheel 11 is a member for steering thefront wheels 8. Thesteering wheel 11 is provided in the front portion of the operation part 10. - The
seat 12 is a member on which an operator sits. Theseat 12 is provided behind thesteering wheel 11. - The
loader operation device 300 operates the working device such as theloader 3 and sets the engine rotational speed of the working vehicle 1 and the like. Theloader operation device 300 is provided at the side (in this embodiment, the right side) of theseat 12. - The backhoe operation device 13 operates the
backhoe 4 and the like. The backhoe operation device 13 is provided behind theseat 12. - The
loader 3 is a working device for conveying earth and sand. Theloader 3 mainly has twobucket lift arms 15, a loader bucket 16, twobucket lift cylinders 17 and twodump cylinders 18. - The
bucket lift arms 15 are a main structure of theloader 3. The rear ends of the bucket liftarms 15 are respectively supported rotatably on the left and right portions of the body frame 5. - The loader bucket 16 is a member loaded with the earth and sand. The loader bucket 16 is rotatably vertically supported at the front ends of the bucket lift
arms 15. - The
bucket lift cylinders 17 are hydraulic cylinders which can be controlled to expand and contract by theloader operation device 300. The rear ends of thebucket lift cylinders 17 are respectively supported rotatably vertically on the left and right portions of the body frame 5. The front ends of thebucket lift cylinders 17 are respectively supported rotatably vertically on the middle portions of the bucket liftarms 15. - The
dump cylinders 18 are hydraulic cylinders which can be controlled to expand and contract by theloader operation device 300. The rear ends of thedump cylinders 18 are respectively supported rotatably vertically on the left and right portions of the body frame 5. The front ends of thedump cylinders 18 are connected respectively through twolink mechanisms 19 to the loader bucket 16. - In the
loader 3 constructed as mentioned above, by expanding and contracting thebucket lift cylinders 17, the bucket liftarms 15 can be moved vertically. By expanding and contracting thedump cylinders 18, the loader bucket 16 can be rotated vertically about the bucket liftarms 15. - By combining the rotational actions of the bucket lift
arms 15 and the loader bucket 16, the working vehicle 1 performs conveyance work of earth and sand. - The
backhoe 4 performs excavation work of earth and sand. Thebackhoe 4 mainly has twostabilizers 20, twostabilizer cylinders 21, aboom bracket 22, twoswing cylinders 23, aboom 24, aboom cylinder 25, anarm 26, anarm cylinder 27, abucket 28 and abucket cylinder 29. - The
stabilizers 20 support the working vehicle 1 at the time of the excavation work with thebackhoe 4. One of ends of each of thestabilizers 20 is supported rotatably vertically at corresponding one of the left and right sides of the rear portion of the body frame 5. - The
stabilizer cylinders 21 are hydraulic cylinders which can be controlled to expand and contract by the backhoe operation device 13. One of ends of each of thestabilizer cylinders 21 is supported rotatably vertically at corresponding one of the left and right sides of the rear portion of the body frame 5. The other end of each of thestabilizer cylinders 21 is supported by the other end of corresponding one of thestabilizers 20. - The
boom bracket 22 is a main structure of thebackhoe 4. The front end of theboom bracket 22 is supported rotatably laterally at the rear end of the body frame 5. - The
swing cylinders 23 are hydraulic cylinders which can be controlled to expand and contract by the backhoe operation device 13. Theswing cylinders 23 are provided respectively at the left and right sides of the body frame 5 and theboom bracket 22. One of ends of each of theswing cylinders 23 is supported rotatably laterally at the rear end of the body frame 5. The other end of each of theswing cylinders 23 is supported rotatably laterally at the front end of theboom bracket 22. - The
boom 24 is a main structure of thebackhoe 4. One of ends of theboom 24 is supported rotatably vertically at the rear end of theboom bracket 22. - The
boom cylinder 25 is a hydraulic cylinder which can be controlled to expand and contract by the backhoe operation device 13. One of ends of theboom cylinder 25 is supported rotatably vertically on upper portion of the rear end of theboom bracket 22. The other end of theboom cylinder 25 is supported rotatably vertically on the middle portion of theboom 24. - The
arm 26 is a main structure of thebackhoe 4. One of ends of thearm 26 is supported rotatably vertically at the other end of theboom 24. - The
arm cylinder 27 is a hydraulic cylinder which can be controlled to expand and contract by the backhoe operation device 13. One of ends of thearm cylinder 27 is supported rotatably vertically on the middle portion of theboom 24. The other end of thearm cylinder 27 is supported rotatably vertically at one of ends of thearm 26. - The
bucket 28 is a member loaded with the earth and sand. One of ends of thebucket 28 is supported rotatably vertically at the other end of thearm 26. - The
bucket cylinder 29 is a hydraulic cylinder which can be controlled to expand and contract by the backhoe operation device 13. One of ends of thebucket cylinder 29 is supported rotatably vertically at the middle portion of thearm 26. The other end of thebucket cylinder 29 is supported rotatably vertically at thebucket 28. - In the
backhoe 4 constructed as mentioned above, by expanding and contracting thestabilizer cylinders 21, the other end of each of thestabilizers 20 can touch the ground. Accordingly, the posture of the working vehicle 1 at the excavation work can be stabilized. - By expanding and contracting the
swing cylinders 23, theboom bracket 22 can be rotated laterally. By expanding and contracting theboom cylinder 25, theboom 24 can be rotated vertically. By expanding and contracting thearm cylinder 27, thearm 26 can be rotated vertically about theboom 24. By expanding and contracting thebucket cylinder 29, thebucket 28 can be rotated vertically about thearm 26. By combining the rotational action of theboom bracket 22, theboom 24, thearm 26 and thebucket 28, the working vehicle 1 performs the excavation work of earth and sand. - Explanation will be given on entire construction of a
hydraulic circuit 100 which is an embodiment of a hydraulic circuit provided in the working vehicle according to the present invention referring toFIG. 2 . - The
hydraulic circuit 100 is provided in the working vehicle 1. Thehydraulic circuit 100 mainly has aHST section 110, areservoir tank 120, ahydraulic pump section 130, a powersteering valve section 140, aloader control valve 200 and abackhoe control valve 150. - The
HST section 110 changes the working vehicle 1 in speed with the power of theengine 6. - The
reservoir tank 120 is an embodiment of a tank according to the present invention and is a container in which pressure oil used in thehydraulic circuit 100 is reserved. A transmission casing provided in the working vehicle 1 may serve as thereservoir tank 120. - The
hydraulic pump section 130 pressingly sends pressure oil with the power of theengine 6. Thehydraulic pump section 130 has aport 131 which is an opening through which pipes are connected. Thehydraulic pump section 130 hasdischarge ports - A
pipe 121 connects thereservoir tank 120 to theport 131 of thehydraulic pump section 130. Thehydraulic pump section 130 sucks pressure oil in thereservoir tank 120 through thepipe 121 and theport 131 and discharge the pressure oil through thedischarge ports - The power
steering valve section 140 controls action of asteering cylinder 141 which controls the steering of thefront wheels 8. The powersteering valve section 140 controls expand and contract of thesteering cylinder 141 corresponding to the operation of thesteering wheel 11. The powersteering valve section 140 has a port 142 which is an opening through which pipes are connected and the like. - A
pipe 135 connects thedischarge port 134 of thehydraulic pump section 130 to the port 142 of the powersteering valve section 140. The powersteering valve section 140 controls the action of thesteering cylinder 141 with the pressure oil supplied through thedischarge port 134 and thepipe 135. - The
loader control valve 200 controls the action of thebucket lift cylinders 17 and thedump cylinders 18. Theloader control valve 200 has apump port 251, atank port 252, a carry-overport 253, dumpcylinder ports lift cylinder ports ports PTO ports - A
pipe 136 connects thedischarge port 133 of thehydraulic pump section 130 to thepump port 251 of theloader control valve 200. - A
pipe 137 connects thedischarge port 132 of thehydraulic pump section 130 to theport 258 of theloader control valve 200. - A
pipe 262 connects thetank port 252 of theloader control valve 200 to thereservoir tank 120. - The
backhoe control valve 150 controls the action of thestabilizer cylinders 21, theswing cylinders 23, theboom cylinder 25, thearm cylinder 27 and thebucket cylinder 29. Thebackhoe control valve 150 hasports - A
pipe 263 connects the carry-overport 253 of theloader control valve 200 to theport 151 of thebackhoe control valve 150. - A
pipe 264 connects theport 259 of theloader control valve 200 to theport 152 of thebackhoe control valve 150. - The
backhoe control valve 150 controls the action of thestabilizer cylinders 21, theswing cylinders 23 and thearm cylinder 27 with the pressure oil supplied through thepipe 263 and theport 151. - The
backhoe control valve 150 controls the action of thestabilizer cylinders 21, thebucket cylinder 29 and theboom cylinder 25 with the pressure oil supplied through thepipe 264 and theport 152. - In this embodiment, in the working vehicle 1, the
backhoe control valve 150 is provided at the downstream of theloader control valve 200. However, the present invention is not limited thereto. Instead of thebackhoe control valve 150, a control valve or the like may alternatively be provided so as to switch the action of the lift cylinder which moves vertically the mounted working machine. It may alternatively be constructed that any control valve or the like is not provided. - Explanation will be given on the construction of the
loader control valve 200 in detail referring toFIG. 3 . - The
loader control valve 200 mainly has a dumpcylinder switching valve 210, a bucket liftcylinder switching valve 220, amode switching valve 230 and aPTO switching valve 240. - The dump
cylinder switching valve 210 is arranged between thepump port 251 and thedump cylinders 18 and switches the flow route of pressure oil pressingly sent to thedump cylinders 18 so as to switch the action of thedump cylinders 18. The dumpcylinder switching valve 210 has six ports and three positions (positions A, B and C). The position of the dumpcylinder switching valve 210 can be switched by operating aloader operation lever 310 provided in theloader operation device 300. - An
oil passage 270 connects thepump port 251 to the dumpcylinder switching valve 210. - An
oil passage 271 connects theoil passage 270 to anoil passage 272. Arelease valve 271 a is provided at the middle portion of theoil passage 271. - The
oil passage 272 is connected to thetank port 252. - An
oil passage 273 connects the dumpcylinder switching valve 210 to a middle portion of anoil passage 274. - The
oil passage 274 connects thedump cylinder port 254 to theoil passage 272. Ananti-void release valve 274 a is provided at the middle portion of theoil passage 274 in the vicinity of the connection part of theoil passage 274 and theoil passage 272. - An
oil passage 275 connects the dumpcylinder switching valve 210 to a middle portion of anoil passage 276. - An
oil passage 276 connects thedump cylinder port 255 to theoil passage 272. Ananti-void release valve 276 a is provided at the middle portion of theoil passage 276 in the vicinity of the connection part of theoil passage 276 and theoil passage 272. - A
pipe 265 connects thedump cylinder port 254 to bottom chambers of thedump cylinders 18. - A
pipe 266 connects thedump cylinder port 255 to rod chambers of thedump cylinders 18. - The pressure oil discharged from the discharge port 133 (see
FIG. 2 ) is pressingly sent through thepipe 136, thepump port 251 and theoil passage 270 to the dumpcylinder switching valve 210. - By switching the dump
cylinder switching valve 210 to the position C, the pressure oil is pressingly sent through theoil passage 273, theoil passage 274, thedump cylinder port 254 and thepipe 265 to the bottom chambers of thedump cylinders 18. Accordingly, thedump cylinders 18 can be expanded. - By switching the dump
cylinder switching valve 210 to the position B, the pressure oil is pressingly sent through theoil passage 275, theoil passage 276, thedump cylinder port 255 and thepipe 266 to the rod chambers of thedump cylinders 18. Accordingly, thedump cylinders 18 can be contracted. - Therefore, by switching the position of the dump
cylinder switching valve 210, thedump cylinders 18 can be expanded and contracted. Accordingly, the loader bucket 16 can be rotated vertically about the bucket liftarms 15. - The bucket lift
cylinder switching valve 220 is arranged between the dumpcylinder switching valve 210 and thebucket lift cylinders 17 and switches the flow route of pressure oil pressingly sent to thebucket lift cylinders 17 so as to switch the action of thebucket lift cylinders 17. The bucket liftcylinder switching valve 220 has six ports and four positions (positions D, E, F and G). The position of the bucket liftcylinder switching valve 220 can be switched by operating theloader operation lever 310 provided in theloader operation device 300. - An
oil passage 277 connects the dumpcylinder switching valve 210 to the bucket liftcylinder switching valve 220. - An
oil passage 278 connects the bucket liftcylinder switching valve 220 to a middle portion of an oil passage 279. - The oil passage 279 connects the bucket
lift cylinder port 256 to theoil passage 272. Acheck valve 279 a is provided at the middle portion of the oil passage 279 in the vicinity of the connection part of the oil passage 279 and theoil passage 272. - An
oil passage 280 connects the bucket liftcylinder switching valve 220 to the bucketlift cylinder port 257. - A
pipe 267 connects the bucketlift cylinder port 256 to rod chambers of thebucket lift cylinders 17. - A
pipe 268 connects the bucketlift cylinder port 257 to bottom chambers of thebucket lift cylinders 17. - When the dump
cylinder switching valve 210 is switched to the position A, the pressure oil passing through the dumpcylinder switching valve 210 is pressingly sent through theoil passage 277 to the bucket liftcylinder switching valve 220. - By switching the bucket lift
cylinder switching valve 220 to the position E, the pressure oil is pressingly sent through theoil passage 280, the bucketlift cylinder port 257 and thepipe 268 to the bottom chambers of thebucket lift cylinders 17. Accordingly, the bottom chambers of thebucket lift cylinders 17 can be expanded. - By switching the bucket lift
cylinder switching valve 220 to the position F, the pressure oil is pressingly sent through theoil passage 278, the oil passage 279, the bucketlift cylinder port 256 and thepipe 267 to the rod chambers of thebucket lift cylinders 17. Accordingly, thebucket lift cylinders 17 can be contracted. - Therefore, by switching the bucket lift
cylinder switching valve 220, thebucket lift cylinders 17 can be expanded and contracted. Accordingly, the bucket liftarms 15 can be moved vertically. - The
mode switching valve 230 is arranged between the bucket liftcylinder switching valve 220 and the carry-overport 253 and switches the flow route of pressure oil. Themode switching valve 230 is a directional control valve having five ports, i.e.ports 230 a and 230 b of the primary side andports - The
mode switching valve 230 can be switched among a “working position H” in which the port 230 a is communicated with theport 230 c, theport 230 d is communicated with theport 230 e, and theport 230 b is blocked, a “return position J” in which the port 230 a, theport 230 b, theport 230 c, theport 230 d and theport 230 e are communicated with each other, and a “confluence position K” in which the port 230 a is communicated with theport 230 c and theport 230 d and theport 230 b is communicated with theport 230 e. - The position of the
mode switching valve 230 can be switched by operating amode switching lever 340 provided in theloader operation device 300. - The
mode switching valve 230 has twosprings 231 and adetent mechanism 232. - The
springs 231 hold the position of themode switching valve 230 at the working position H. Though themode switching valve 230 has thesprings 231 in this embodiment, the present invention is not limited thereto. It may alternatively be constructed that themode switching valve 230 does not have thesprings 231. - The
detent mechanism 232 holds the position of themode switching valve 230 at the return position J or the confluence position K. When themode switching valve 230 is switched to the return position J or the confluence position K, thedetent mechanism 232 holds the position of themode switching valve 230 at corresponding one of the return position J and the confluence position K. By operating themode switching lever 340 with operation force larger than the holding force of thedetent mechanism 232, themode switching valve 230 can be switched to the other position. - An
oil passage 281 connects the bucket liftcylinder switching valve 220 to the port 230 a of themode switching valve 230. - An
oil passage 282 connects theport 230 b of themode switching valve 230 to the oil passage 272 (in its turn the reservoir tank 120). - An oil passage 283 connects the
port 230 d of themode switching valve 230 to the port 258 (in its turn thedischarge port 132 of the hydraulic pump). - An
oil passage 284 connects theport 230 e of themode switching valve 230 to a middle portion of an oil passage 285 (in its turn theport 152 of the backhoe control valve 150). - The
oil passage 285 connects theoil passage 272 to theport 259. Ananti-void release valve 285 a is provided at the middle portion of theoil passage 285 in the vicinity of the connection part of theoil passage 285 and theoil passage 272. - The
PTO switching valve 240 is arranged between themode switching valve 230 and the carry-overport 253 and switches the flow route of pressure oil sent to thePTO ports PTO switching valve 240 is a directional control valve having six ports, i.e.ports ports - The
PTO switching valve 240 can be switched among a “position L” in which theport 240 a is communicated with theport 240 d and theports port 240 b is communicated with theport 240 f, the port 240 c is communicated with theport 240 e and theports port 240 b is communicated with theport 240 e, the port 240 c is communicated with theport 240 f and theports port 240 b is communicated with theport 240 e, the port 240 c is communicated with theport 240 f and theports - The
PTO switching valve 240 can be switched by operating aPTO switching lever 360 provided in theloader operation device 300. - The
PTO switching valve 240 has two springs 241 and adetent mechanism 242. - The springs 241 hold the position of the
PTO switching valve 240 at the position L. - The
detent mechanism 242 holds the position of thePTO switching valve 240 at the continuous position P. When thePTO switching valve 240 is switched to the continuous position P, thedetent mechanism 242 holds the position of thePTO switching valve 240 at the continuous position P. By operating thePTO switching lever 360 with operation force larger than the holding force of thedetent mechanism 242, thePTO switching valve 240 can be switched to the other position. - An
oil passage 286 connects theport 230 c of themode switching valve 230 to theport 240 a of thePTO switching valve 240. - An oil passage 287 connects the middle portion of the
oil passage 286 to theport 240 b of thePTO switching valve 240. A check valve 287 a is provided at the middle portion of the oil passage 287. - An
oil passage 288 connects the port 240 c of thePTO switching valve 240 to theoil passage 272. - An
oil passage 289 connects theport 240 d of thePTO switching valve 240 to the carry-overport 253. - An
oil passage 290 connects theport 240 e of thePTO switching valve 240 to anoil passage 291. - The
oil passage 291 connects thePTO port 260 to theoil passage 272. Aplug 291 a is provided at the middle portion of theoil passage 291 in the vicinity of the connection part of theoil passage 291 and theoil passage 272. If necessary, instead of theplug 291 a, a release valve or the like may alternatively be interposed. - An
oil passage 292 connects theport 240 f of thePTO switching valve 240 to a middle portion of anoil passage 293. - The
oil passage 293 connects thePTO port 261 to theoil passage 272. Aplug 293 a is provided at the middle portion of theoil passage 293 in the vicinity of the connection part of theoil passage 293 and theoil passage 272. If necessary, instead of theplug 293 a, a release valve or the like may alternatively be interposed. - The
mode switching lever 340 and thePTO switching lever 360 have aninterlock mechanism 400. Theinterlock mechanism 400 restricts the action of the mode switching lever 340 (in its turn, the action of the mode switching valve 230) based on the position of the PTO switching lever 360 (in its turn, the position of the PTO switching valve 240). More concretely, theinterlock mechanism 400 restricts the action of themode switching lever 340 so that themode switching valve 230 can be switched to the confluence position K only in the case that thePTO switching valve 240 is at the continuous position P. - Explanation will be given on the switching of the flow route of pressure oil with the
mode switching valve 230 and thePTO switching valve 240 constructed as mentioned above. - When the excavation work or the like is performed with the
backhoe 4, themode switching valve 230 is switched to the working position H. In this case, thePTO switching valve 240 is not operated, whereby thePTO switching valve 240 is held at the position L by the springs 241. - In this case, the pressure oil discharged from the discharge port 133 (see
FIG. 2 ) is pressingly sent through thepipe 136, thepump port 251, theoil passage 270, the dumpcylinder switching valve 210, theoil passage 277, the bucket liftcylinder switching valve 220, theoil passage 281, themode switching valve 230, theoil passage 286, thePTO switching valve 240, theoil passage 289, the carry-overport 253 and thepipe 263 to the backhoe control valve 150 (seeFIG. 2 ). - The pressure oil discharged from the discharge port 132 (see
FIG. 2 ) is pressingly sent through thepipe 137, theport 258, the oil passage 283, themode switching valve 230, theoil passage 284, theoil passage 285, theport 259 and thepipe 264 to the backhoe control valve 150 (seeFIG. 2 ). - As mentioned above, the pressure oil discharged from the
discharge ports backhoe control valve 150. Thebackhoe 4 is driven with the pressure oil pressingly sent. - In the case that a working machine is connected to the
PTO ports mode switching valve 230 is switched to the working position H. - In this case, the pressure oil discharged from the discharge port 133 (see
FIG. 2 ) is pressingly sent through thepipe 136, thepump port 251, theoil passage 270, the dumpcylinder switching valve 210, theoil passage 277, the bucket liftcylinder switching valve 220, theoil passage 281, themode switching valve 230, and theoil passages 286 and 287 to thePTO switching valve 240. By operating thePTO switching lever 360 so as to switch thePTO switching valve 240 to the position M or N, the pressure oil pressingly sent can be extracted through thePTO port 260 or thePTO port 261. The working machine is driven with the extracted pressure oil. - In the case of conveying work of earth and sand with the
loader 3 or in the case of traveling, themode switching valve 230 is switched to the return position J. - In this case, the pressure oil discharged from the discharge port 133 (see
FIG. 2 ) is pressingly sent through thepipe 136, thepump port 251 and theoil passage 270 to the dumpcylinder switching valve 210. By operating the dumpcylinder switching valve 210 and the bucket liftcylinder switching valve 220, theloader 3 is operated with the pressure oil pressingly sent. The pressure oil discharged from thedischarge port 133 and passing through the dumpcylinder switching valve 210 and the bucket liftcylinder switching valve 220 is pressingly sent through theoil passage 281 to themode switching valve 230. - The pressure oil discharged from the discharge port 132 (see
FIG. 2 ) is pressingly sent through thepipe 137, theport 258 and the oil passage 283 to themode switching valve 230. - The pressure oil discharged from the
discharge ports mode switching valve 230 is returned through theoil passage 282, theoil passage 272, thetank port 252 and thepipe 262 to the reservoir tank 120 (seeFIG. 2 ). - As mentioned above, by switching the
mode switching valve 230 to the return position J, the pressure oil discharged from thedischarge port 132 can be returned to thereservoir tank 120 through the short route. Accordingly, in the case that any work is not performed with thebackhoe 4, pressure loss caused by the pipes can be reduced, whereby the engine power can be used effectively. - At the time of starting the
engine 6, by switching themode switching valve 230 to the return position J, pressure loss caused by the pipes can be reduced, whereby the starting ability of theengine 6 can be improved. Accordingly, at the operation environment with external air of low temperature, good starting ability of theengine 6 can be obtained. - In the case that a working machine requiring larger flow rate than the flow rate of pressure oil discharged from the
discharge port 133 is connected to thePTO ports PTO switching valve 240 is switched to the continuous position P. Then, the restriction of action of themode switching valve 230 by theinterlock mechanism 400 is released. Subsequently, themode switching valve 230 is switched to the confluence position K. - In this case, the pressure oil discharged from the discharge port 133 (see
FIG. 2 ) is pressingly sent through thepipe 136, thepump port 251, theoil passage 270, the dumpcylinder switching valve 210, theoil passage 277, the bucket liftcylinder switching valve 220, and theoil passage 281 to themode switching valve 230. - The pressure oil discharged from the discharge port 132 (see
FIG. 2 ) is pressingly sent through thepipe 137, theport 258 and the oil passage 283 to themode switching valve 230. - The pressure oil discharged from the
discharge ports mode switching valve 230 is combined in themode switching valve 230. The combined pressure oil is pressingly sent through theoil passages 286 and 287, theinterlock mechanism 400, theoil passage 290, theoil passage 291 and thePTO port 260 to the connected working machine. - As mentioned above, the working vehicle 1 in this embodiment comprises
- the two hydraulic pumps pressingly sending pressure oil and independent of each other,
- the
mode switching valve 230 which can be switched to the confluence position K at which the pressure oil pressingly sent by the two hydraulic pumps is combined, - the
PTO ports - the
PTO switching valve 240 arranged downstream themode switching valve 230 and switched so as to send pressingly the pressure oil to thePTO ports - In this construction, by switching the
mode switching valve 230 to the confluence position K, the pressure oil discharged from thedischarge ports discharge ports - The
mode switching valve 230 is provided integrally in theloader control valve 200 having thePTO switching valve 240. - According to this construction, it is not necessary to secure separately a space in which the
mode switching valve 230 is arranged, whereby the space is saved. Furthermore, any pipe connecting themode switching valve 230 to theloader control valve 200 is not required, whereby the part number and cost are reduced. - The present invention is not limited to this construction, and the
mode switching valve 230 may alternatively be constructed independently of theloader control valve 200. - By employing the loader control valve constructed as this embodiment, the piping construction of the
hydraulic circuit 100 provided in the working vehicle 1 can be simplified. Concretely, a three way joint required at aconnection part 537 a between apipe 537 and apipe 564 shown inFIG. 14 can be made unnecessary. Accordingly, the piping construction of thehydraulic circuit 100 can be simplified so as to reduce the part number and reduce the number of assembly processes. - The
mode switching valve 230 can be switched among the confluence position K, the return position J at which the pressure oil pressingly sent by the two hydraulic pumps is returned to thereservoir tank 120, and the working position H at which the pressure oil pressingly sent by the two hydraulic pumps is pressingly sent to thebackhoe control valve 150 arranged at the downstream side without combining the pressure oil. - According to this construction, by switching the
mode switching valve 230 to the return position J, the pressure oil can be returned to thereservoir tank 120 with the short route. Accordingly, pressure loss caused by the pipes and the like in thehydraulic circuit 100 can be reduced. Since the confluence position K, the return position J and the working position H are provided in the same valve, it is not necessary to secure separately a space in which the valve is arranged, whereby the space is saved. Furthermore, by providing the positions in the same valve, the part number and cost can be reduced. - The
PTO switching valve 240 has - the continuous position P at which pressure oil is held to be able to be sent pressingly to the
PTO ports - the
interlock mechanism 400 which makes themode switching valve 230 able to be switched to the confluence position K only in the case that thePTO switching valve 240 is switched to the continuous position P. - According to this construction, the safety of the working vehicle 1 can be improved.
- Concretely, in the case that the
PTO switching valve 240 is at the position L, when themode switching valve 230 is switched to the confluence position K, the pressure oil combined in themode switching valve 230 is pressingly sent through theoil passage 286, thePTO switching valve 240, theoil passage 289, the carry-overport 253, thepipe 263 and theport 151 to thebackhoe control valve 150. On the other hand, any pressure oil is not supplied from theport 152 to thebackhoe control valve 150. - In this case, the
stabilizer cylinders 21, theswing cylinders 23 and thearm cylinder 27 shown inFIG. 2 are operated at high speed by the pressure oil supplied from theport 151, and the state is realized that thestabilizer cylinders 21, thebucket cylinder 29 and theboom cylinder 25 are not operated at all (hereinafter, the state is simply referred to as “wrong operation state”). When thebackhoe 4 is operated at the wrong operation state, thebackhoe 4 may act against operator's will. The action against the operator's will may cause defects such as instability of posture of the working vehicle 1. - According to the
interlock mechanism 400, themode switching valve 230 can be switched to the confluence position K only in the case that thePTO switching valve 240 is at the continuous position P, whereby the pressure oil combined in themode switching valve 230 is prevented from being supplied to thebackhoe control valve 150. Accordingly, the wrong operation state as mentioned above can be prevented so as to improve the safety of the working vehicle 1. - Explanation will be given on the construction of the
loader operation device 300 in detail referring toFIG. 4 . For convenience of the explanation, inFIG. 4 , thepipes - The
loader operation device 300 mainly has theloader control valve 200, theloader operation lever 310, adump link mechanism 320, abucket link mechanism 330, themode switching lever 340, a modeswitching link mechanism 350, thePTO switching lever 360, aPTO link mechanism 370, alimit switch 380 and athrottle lever 390. - As mentioned above, the
loader control valve 200 controls the action of thebucket lift cylinders 17, thedump cylinders 18 and the like. Theloader control valve 200 is provided at the right side of theseat 12. Theloader control valve 200 mainly has the dumpcylinder switching valve 210, the bucket liftcylinder switching valve 220, themode switching valve 230 and thePTO switching valve 240. - The
loader operation lever 310 switches the positions of the dumpcylinder switching valve 210 and the bucket liftcylinder switching valve 220. Theloader operation lever 310 is arranged above theloader control valve 200. - The
dump link mechanism 320 connects theloader operation lever 310 to the dumpcylinder switching valve 210. - By operating laterally the
loader operation lever 310, the position of the dumpcylinder switching valve 210 can be switched. - The
bucket link mechanism 330 connects theloader operation lever 310 to the bucket liftcylinder switching valve 220. - By operating laterally the
loader operation lever 310, the position of the bucket liftcylinder switching valve 220 can be switched. - The
mode switching lever 340 switches the position of themode switching valve 230. Themode switching lever 340 is arranged above theloader control valve 200 and behind theloader operation lever 310. Themode switching lever 340 mainly has aboss part 341, agrip part 342, anarm part 343 and acam part 344. - The
boss part 341 is substantially cylindrical. Theboss part 341 is rotatably supported by apivot shaft 345 whose axial direction is substantially the same as the lateral direction. - The
grip part 342 is substantially cylindrical. One of ends of thegrip part 342 is fixed to the outer peripheral surface of theboss part 341. The other end of thegrip part 342 is extended rearward and upward. Agrip 342 a is provided at the other end of thegrip part 342. - The
arm part 343 is substantially rectangular plate-like. One of ends of thearm part 343 is fixed to the outer peripheral surface of theboss part 341. The other end of thearm part 343 is extended forward. - The
cam part 344 is substantially plate-like. One of ends of thecam part 344 is fixed to the outer peripheral surface of theboss part 341. The other end of thecam part 344 is extended rearward, and the tip thereof is formed substantially triangularly. - The mode
switching link mechanism 350 connects the other end of thearm part 343 to themode switching valve 230. - At the time of switching the position of the
mode switching valve 230, an operator grips the grip part 342 (thegrip 342 a) of themode switching lever 340 and operates longitudinally themode switching lever 340. By rotating theboss part 341 centering on thepivot shaft 345, the other end of thearm part 343 is rotated vertically. Accordingly, the position of themode switching valve 230 is switched via the modeswitching link mechanism 350. - The
PTO switching lever 360 switches the position of thePTO switching valve 240. ThePTO switching lever 360 is arranged above theloader control valve 200 and behind theloader operation lever 310. ThePTO switching lever 360 mainly has aboss part 361, agrip part 362, anarm part 363, acam part 364 and atouching part 365. - The
boss part 361 is substantially cylindrical. Theboss part 361 is rotatably supported by apivot shaft 366 whose axial direction is substantially the same as the lateral direction. Theboss part 361 is arranged below and behind theboss part 341 of themode switching lever 340. - The
grip part 362 is substantially cylindrical. One of ends of thegrip part 362 is fixed to the outer peripheral surface of theboss part 361. The other end of thegrip part 362 is extended upward. Agrip 362 a is provided at the other end of thegrip part 362. - The
arm part 363 is substantially rectangular plate-like. One of ends of thearm part 363 is fixed to the outer peripheral surface of theboss part 361. The other end of thearm part 363 is extended forward. - The
cam part 364 is substantially plate-like. One of ends of thecam part 364 is fixed to the outer peripheral surface of theboss part 361. The other end of thecam part 364 is extended forward. Thecam part 364 of thePTO switching lever 360 is arranged substantially the same plane position as thecam part 344 of themode switching lever 340 in the lateral direction. - The
touching part 365 is substantially plate-like. One of ends of thetouching part 365 is fixed to the outer peripheral surface of theboss part 361. The other end of thetouching part 365 is extended rearward. - The
PTO link mechanism 370 connects the other end of thearm part 363 to thePTO switching valve 240. - At the time of switching the position of the
PTO switching valve 240, an operator grips the grip part 362 (thegrip 362 a) of thePTO switching lever 360 and operates longitudinally thePTO switching lever 360. By rotating theboss part 361 centering on thepivot shaft 366, the other end of thearm part 363 is rotated vertically. Accordingly, the position of thePTO switching valve 240 is switched via thePTO link mechanism 370. - The
limit switch 380 is an embodiment of a starting inhibition means according to the present invention, and is a switch whose contact point is engaged/disengaged corresponding to whether anoperation chip 381 is pressed or not. Thelimit switch 380 is arranged below and behind theboss part 361 of thePTO switching lever 360 and below thetouching part 365 of thePTO switching lever 360. In more detail, in the case that thePTO switching valve 240 is switched to the continuous position P, thelimit switch 380 is arranged at the position at which theoperation chip 381 of thelimit switch 380 is pressed by thetouching part 365 of thePTO switching lever 360. - When the
operation chip 381 of thelimit switch 380 is pressed, drive of a starter (not shown) starting theengine 6 is inhibited. Namely, when theoperation chip 381 of thelimit switch 380 is pressed, theengine 6 cannot be started. - The
throttle lever 390 sets the rotational speed of theengine 6 of the working vehicle 1 (hereinafter, simply referred to as “engine rotational speed”). Thethrottle lever 390 is arranged behind thePTO switching lever 360. Thethrottle lever 390 is rotatable longitudinally centering on the lower end thereof By operating rotationally thethrottle lever 390, the engine rotational speed can be set. Concretely, by rotating forward thethrottle lever 390, the engine rotational speed can be increased. By rotating rearward thethrottle lever 390, the engine rotational speed can be reduced. - The
interlock mechanism 400 has thecam part 344 of themode switching lever 340 and thecam part 364 of thePTO switching lever 360. - Explanation will be given on the action mode of the
interlock mechanism 400 referring toFIGS. 5 to 9 . - For convenience of the explanation, the position of the
mode switching lever 340 in the case that themode switching valve 230 is at the working position H is defined as a lever position Q, the position of themode switching lever 340 in the case that themode switching valve 230 is at the return position J is defined as a lever position R, and the position of themode switching lever 340 in the case that themode switching valve 230 is at the confluence position K is defined as a lever position S. - The positions of the
PTO switching lever 360 in the case that thePTO switching valve 240 is at the positions L, M and N and the continuous position P are respectively defined as lever positions T, U, V and W. - In
FIGS. 5 to 9 , together with the reference letters of the lever positions, the reference letters of the positions of themode switching valve 230 and thePTO switching valve 240 corresponding to the lever positions are shown in parentheses. - As shown in
FIG. 5 , in the case that thePTO switching lever 360 is at the lever position T, themode switching lever 340 can be switched to the lever position Q or the lever position R. Namely, the other end of thecam part 364 of thePTO switching lever 360 is positioned in the rotational locus of thecam part 344 of themode switching lever 340 while directing upward so as to restrict the rotational range of themode switching lever 340, but is not within the rotational range of themode switching lever 340 to be switched to the lever position Q or the lever position R and does not affect the rotation. In the case that themode switching lever 340 is switched to the lever position Q, alower surface 344 a of thecam part 344 of themode switching lever 340 touches anupper surface 364 a of thecam part 364 of thePTO switching lever 360. Namely, thecam part 364 of thePTO switching lever 360 restricts the rotation of themode switching lever 340 toward the lever position S. Accordingly, themode switching lever 340 cannot be switched to the lever position S. Namely, themode switching valve 230 cannot be switched to the confluence position K, whereby the pressure oil discharged from one of thedischarge ports - Similarly to the above, in the case that the
PTO switching lever 360 is switched to the lever position U or the lever position V, the rotation of themode switching lever 340 toward the lever position S is also restricted. Accordingly, themode switching lever 340 cannot be switched to the lever position S. Namely, themode switching valve 230 cannot be switched to the confluence position K. - As shown in
FIG. 6 , in the case that thePTO switching lever 360 is switched to the lever position W, theoperation chip 381 of thelimit switch 380 is pressed by thetouching part 365 of thePTO switching lever 360. - As mentioned above, the
limit switch 380 is provided which inhibits the starting of theengine 6 in the case that thePTO switching valve 240 is switched to the continuous position P. - According to the construction, in the case that the
PTO switching valve 240 is switched to the continuous position P, theengine 6 cannot be started. Namely, the working machine connected to thePTO ports engine 6. Accordingly, at the time of maintenance of the working machine or the like, the working machine is prevented from being driven simultaneously to the starting of theengine 6, whereby the safety of maintenance work of the working machine and the like is improved. - In this embodiment, the starting inhibition means according to the present invention is constructed by the
limit switch 380, but the present invention is not limited thereto. The starting inhibition means only must be constructed so as to detect that thePTO switching valve 240 is switched to the continuous position P and inhibit the starting of theengine 6. - In the case that the
PTO switching lever 360 is switched to the lever position W, thelower surface 344 a of thecam part 344 of themode switching lever 340 does not touch theupper surface 364 a of thecam part 364 of thePTO switching lever 360. Namely, thecam part 364 at the lever position W is not within the rotational range of thecam part 344 of themode switching lever 340, and the restriction of the rotation of themode switching lever 340 toward the lever position S by thecam part 364 of thePTO switching lever 360 is canceled. Accordingly, only in the case that thePTO switching lever 360 is switched to the lever position W, themode switching lever 340 can be switched to the lever position S. Namely, themode switching valve 230 can be switched to the confluence position K only in the case that thePTO switching valve 240 is at the continuous position P. - According to the construction, the pressure oil combined in the
mode switching valve 230 is prevented from being pressingly sent to theport 151 of thebackhoe control valve 150. Accordingly, the wrong operation state of thebackhoe 4 can be prevented so as to improve the safety of the working vehicle 1. - In the case that the
PTO switching lever 360 is at the lever position W and themode switching lever 340 is at the lever position S (FIG. 6 ), when thePTO switching lever 360 is switched to the lever position U, as shown inFIG. 7 , avertex 364 b of thecam part 364 of thePTO switching lever 360 touches a lowerrear surface 344 b of thecam part 344 of themode switching lever 340. When thePTO switching lever 360 is rotated toward the lever position U further from this state, thecam part 344 of themode switching lever 340 is pressed by thecam part 364 of thePTO switching lever 360, whereby themode switching lever 340 is rotated toward the lever position Q. - As shown in
FIG. 8 , in the middle of the rotation of thePTO switching lever 360 from the lever position W to the lever position U, thevertex 364 b of thecam part 364 of thePTO switching lever 360 pushes themode switching lever 340 toward the lever position Q while sliding on the lowerrear surface 344 b of thecam part 344 and touches avertex 344 c of thecam part 344 of themode switching lever 340. In this case, themode switching lever 340 is rotated to a position for predetermined angle toward the lever position R from the lever position Q (lever position Qa). Namely, themode switching valve 230 is moved across the working position H toward the return position J for predetermined dimension. - As shown in
FIG. 9 , when thePTO switching lever 360 is switched to the lever position T, themode switching valve 230 is returned to the working position H and held at the position by thesprings 231. Simultaneously, themode switching lever 340 is returned to the lever position Q and held at the position. - According to the construction, in the case that the working machine connected to the
PTO ports PTO switching lever 360 from the lever position W to the lever position T, themode switching lever 340 can be returned simultaneously from the lever position S to the lever position Q. Namely, by operating thePTO switching lever 360, themode switching valve 230 can be switched to the working position H. - As mentioned above, in the
interlock mechanism 400, when thePTO switching valve 240 is switched from the continuous position P to one of the other positions L, M and N, themode switching valve 230 is switched from the confluence position K to one of the other positions (the working position H or the return position J). - According to the construction, the wrong operation state of the
backhoe 4 can be prevented so as to improve the safety. - In the
interlock mechanism 400, in the middle of switching of thePTO switching valve 240 from the continuous position P to one of the other positions L, M and N, themode switching valve 230 is moved to the position across the position other than the confluence position K (the working position H or the return position J) for the predetermined dimension. - According to the construction, the
mode switching valve 230 can be switched certainly to the working position H. - The predetermined angle and the predetermined dimension are set so that the
mode switching valve 230 can be returned to the working position H by thesprings 231. - As described later, the
loader operation device 300 may alternatively has a throttlelever restriction mechanism 450 which is an embodiment of an engine rotational speed restriction means according to the present invention. - As shown in
FIG. 10 , the throttlelever restriction mechanism 450 restricts the rotatable range of thethrottle lever 390 based on the position of themode switching lever 340. The throttlelever restriction mechanism 450 mainly has anintermediate link member 451, mode switchinglever link members lever link members 454 and 455. - The
intermediate link member 451 is substantially triangular and plate-like. The lower end of theintermediate link member 451 is supported rotatably longitudinally by apivot shaft 451 a. - The mode switching
lever link member 452 is substantially rectangular plate-like. One of ends of the mode switchinglever link member 452 is supported rotatably vertically by apivot shaft 452 a at the upper end of theintermediate link member 451. - The mode switching
lever link member 453 is substantially rectangular plate-like. One of ends of the mode switchinglever link member 453 is fixed to the other end of the mode switchinglever link member 452. A throughhole 453 a is formed at the other end of the mode switchinglever link member 453 and penetrates it. The operator grips thegrip part 342 of themode switching lever 340 is inserted into the throughhole 453 a. - The throttle lever link member 454 is substantially rectangular plate-like. One of ends of the throttle lever link member 454 is supported rotatably vertically by a
pivot shaft 454 a at the vertical middle portion of theintermediate link member 451. - The throttle
lever link member 455 is substantially rectangular plate-like. One of ends of the throttlelever link member 455 is fixed to the other end of the throttle lever link member 454. A throughhole 455 a is formed at the other end of the throttlelever link member 455 and penetrates it. The lengthwise direction of the throughhole 455 a is in agreement with the longitudinal direction. Thethrottle lever 390 is inserted into the throughhole 455 a. - Explanation will be given on the operation mode of the throttle
lever restriction mechanism 450 constructed as the above. - In the case that the
mode switching lever 340 is at one of the positions except the lever position S, thethrottle lever 390 can be rotated longitudinally from the position at which the engine rotational speed is the minimum to the position at which the engine rotational speed is the maximum (hereinafter, simply referred to as “lever position X”). The throughhole 455 a of the throttlelever link member 455 is formed so as not to touch thethrottle lever 390 when thethrottle lever 390 is rotated in the case that themode switching lever 340 is at one of the positions except the lever position S. - As shown in
FIG. 11 , when themode switching lever 340 is switched to the lever position S, the mode switchinglever link members mode switching lever 340. By the movement of the mode switchinglever link members intermediate link member 451 is rotated rearward. By the rearward movement of theintermediate link member 451, the throttlelever link members 454 and 455 are moved rearward. - In this case, the through
hole 455 a of the throttlelever link member 455 is also moved rearward, whereby the forward rotation of thethrottle lever 390 is restricted. Namely, in the case that thethrottle lever 390 is at the lever position X, when themode switching lever 340 is switched to the lever position S, thethrottle lever 390 is rotated rearward for predetermined rotational angle by the throttlelever link member 455. - In this case, when the
throttle lever 390 is rotated forward, thethrottle lever 390 touches the inner peripheral front end of the throughhole 455 a of the throttlelever link member 455, whereby thethrottle lever 390 cannot be rotated to the lever position X. Accordingly, the engine rotational speed is restricted not more than a predetermined value. - The predetermined value of the engine rotational speed is set previously for suppressing the temperature of pressure oil in the working vehicle 1 so as not to cause extraordinariness.
- As mentioned above, the working vehicle 1 in this embodiment has the throttle
lever restriction mechanism 450 which restricts the engine rotational speed not more than the predetermined rotational speed in the case that themode switching valve 230 is switched to the confluence position K. - According to the construction, in the case that the
mode switching lever 340 is at the lever position S, that is, themode switching valve 230 is at the confluence position K, the rotation of thethrottle lever 390 can be restricted so as to restrict the engine rotational speed not more than the predetermined value. Simultaneously, the discharge amount of pressure oil by the hydraulic pump provided in thehydraulic pump section 130 can be reduced. Accordingly, the rising of temperature of pressure oil in the case that themode switching valve 230 is switched to the confluence position K is suppressed, whereby extraordinariness such as overheating can be prevented. - As mentioned above, the through
hole 455 a formed in the throttlelever link member 455 is formed so as to restrict the rotation of thethrottle lever 390, that is, restrict the engine rotational speed not more than the predetermined value in the case that themode switching lever 340 is at the lever position S. - As another embodiment of the engine rotational speed restriction means according to the present invention, a throttle
lever restriction mechanism 460 described below may alternatively be provided. - As shown in
FIG. 12 , the throttlelever restriction mechanism 460 has alink member 461. Thelink member 461 is plate-like. - A through
hole 461 a is formed in one of ends of thelink member 461 and penetrates it. The operator grips thegrip part 342 of themode switching lever 340 is inserted into the throughhole 461 a. - A through
hole 461 b is formed in the other end of thelink member 461 and penetrates it. The lengthwise direction of the throughhole 461 b is in agreement with the longitudinal direction. Thethrottle lever 390 is inserted into the throughhole 461 b. - Explanation will be given on the operation mode of the throttle
lever restriction mechanism 460 constructed as the above. - In the case that the
mode switching lever 340 is at one of the positions except the lever position S, thethrottle lever 390 can be rotated longitudinally from the position at which the engine rotational speed is the minimum to the position at which the engine rotational speed is the maximum (lever position X). The dimension of the throughhole 461 b of thelink member 461 is formed so as not to touch thethrottle lever 390 when thethrottle lever 390 is rotated in the case that themode switching lever 340 is at one of the positions except the lever position S. - When the
mode switching lever 340 is switched to the lever position S, thelink member 461 is moved rearward interlockingkly with the rotation of themode switching lever 340. In this case, the throughhole 461 b of thelink member 461 is also moved rearward, whereby the forward rotation of thethrottle lever 390 is restricted. Namely, in the case that thethrottle lever 390 is at the lever position X, when themode switching lever 340 is switched to the lever position S, thethrottle lever 390 is rotated rearward for predetermined rotational angle by thelink member 461. - In this case, when the
throttle lever 390 is rotated forward, thethrottle lever 390 touches the inner peripheral front end of the throughhole 461 b of thelink member 461, whereby thethrottle lever 390 cannot be rotated to the lever position X. Accordingly, the engine rotational speed is restricted not more than a predetermined value. - As another embodiment of the engine rotational speed restriction means according to the present invention, a throttle
lever restriction mechanism 470 described below may alternatively be provided. - As shown in
FIG. 13 , the throttlelever restriction mechanism 470 has a mode switchinglever arm 471, athrottle lever arm 472, acable 473 and the like. - The mode switching
lever arm 471 is substantially cylindrical. One of ends of the mode switchinglever arm 471 is fixed to the outer peripheral surface of theboss part 341. The other end of the mode switchinglever arm 471 is extended downward. - The
throttle lever arm 472 is substantially cylindrical. One of ends of thethrottle lever arm 472 is fixed to the lower end of thethrottle lever 390. The other end of thethrottle lever arm 472 is extended downward. - The
cable 473 is string-like and connects the mode switchinglever arm 471 to thethrottle lever arm 472. One of ends of thecable 473 is connected to the other end of the mode switchinglever arm 471. The other end of thecable 473 is connected to the other end of thethrottle lever arm 472. - Explanation will be given on the operation mode of the throttle
lever restriction mechanism 460 constructed as the above. - In the case that the
mode switching lever 340 is at one of the positions except the lever position S, thethrottle lever 390 can be rotated longitudinally from the position at which the engine rotational speed is the minimum to the position at which the engine rotational speed is the maximum (lever position X). The dimension (length) of thecable 473 is formed so as not to restrict the rotation of thethrottle lever 390 when thethrottle lever 390 is rotated in the case that themode switching lever 340 is at one of the positions except the lever position S. - When the
mode switching lever 340 is switched to the lever position S, the mode switchinglever arm 471 is rotated interlockingkly with the rotation of themode switching lever 340. By rotating the mode switchinglever arm 471, the other end of thethrottle lever arm 472 is pulled forward via thecable 473. Namely, in the case that thethrottle lever 390 is at the lever position X, when themode switching lever 340 is switched to the lever position S, thethrottle lever 390 is rotated rearward for predetermined rotational angle by thecable 473. - In this case, when the
throttle lever 390 is rotated forward, the rotation of thethrottle lever arm 472 is restricted by thecable 473, whereby thethrottle lever 390 cannot be rotated to the lever position X. Accordingly, the engine rotational speed is restricted not more than a predetermined value. - The engine rotational speed restriction means according to the present invention is not limited to the construction such as the throttle
lever restriction mechanisms mode switching lever 340 is switched to the lever position S. - The present invention can be employed for an art of a working vehicle having two or more hydraulic pumps.
Claims (11)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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JP2008-2257 | 2008-09-02 | ||
JP2008225257A JP5368752B2 (en) | 2008-09-02 | 2008-09-02 | Hydraulic circuit of work vehicle |
JP2008-225257 | 2008-09-02 | ||
PCT/JP2009/063865 WO2010026848A1 (en) | 2008-09-02 | 2009-08-05 | Hydraulic circuit for working machine |
Publications (3)
Publication Number | Publication Date |
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US20110168283A1 US20110168283A1 (en) | 2011-07-14 |
US20120048409A9 true US20120048409A9 (en) | 2012-03-01 |
US8713931B2 US8713931B2 (en) | 2014-05-06 |
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Application Number | Title | Priority Date | Filing Date |
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US13/061,678 Expired - Fee Related US8713931B2 (en) | 2008-09-02 | 2009-08-05 | Hydraulic circuit for working machine |
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US (1) | US8713931B2 (en) |
JP (1) | JP5368752B2 (en) |
CA (1) | CA2735253C (en) |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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US8483917B2 (en) * | 2011-08-08 | 2013-07-09 | Komatsu Ltd. | Backhoe loader |
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Publication number | Priority date | Publication date | Assignee | Title |
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CN104995412B (en) * | 2013-03-22 | 2017-03-29 | 株式会社日立建机Tierra | The fluid pressure drive device of engineering machinery |
EP3212854B1 (en) | 2014-10-29 | 2023-01-18 | Clark Equipment Company | Mechanical linkage for control of power machine |
EP3244069A4 (en) * | 2015-01-06 | 2017-12-27 | Sumitomo Heavy Industries, Ltd. | Construction apparatus |
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Publication number | Priority date | Publication date | Assignee | Title |
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US5083428A (en) * | 1988-06-17 | 1992-01-28 | Kabushiki Kaisha Kobe Seiko Sho | Fluid control system for power shovel |
US7389640B2 (en) * | 2002-04-10 | 2008-06-24 | Luk Lamellen Und Kupplungsbau Beteiligungs Kg | Hydraulic system and automatic transmission |
US20090077958A1 (en) * | 2005-03-14 | 2009-03-26 | Masaaki Yamashita | Hydraulic Circuit Structure of Work Vehicle |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
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JPS62178631A (en) * | 1986-01-31 | 1987-08-05 | Yutani Juko Kk | Specific attachment circuit for oil-pressure shovel |
JP4106011B2 (en) | 2003-10-14 | 2008-06-25 | ナブテスコ株式会社 | Hydraulic circuit and junction valve |
JP2005351442A (en) * | 2004-06-14 | 2005-12-22 | Hitachi Constr Mach Co Ltd | Flow rate switch valve device for attachment of construction machinery |
JP2006329248A (en) * | 2005-05-24 | 2006-12-07 | Kobelco Contstruction Machinery Ltd | Hydraulic pressure supply device for working machine |
JP3813164B2 (en) * | 2005-10-11 | 2006-08-23 | 株式会社クボタ | Backhoe hydraulic system |
-
2008
- 2008-09-02 JP JP2008225257A patent/JP5368752B2/en not_active Expired - Fee Related
-
2009
- 2009-08-05 CA CA 2735253 patent/CA2735253C/en not_active Expired - Fee Related
- 2009-08-05 WO PCT/JP2009/063865 patent/WO2010026848A1/en active Application Filing
- 2009-08-05 US US13/061,678 patent/US8713931B2/en not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5083428A (en) * | 1988-06-17 | 1992-01-28 | Kabushiki Kaisha Kobe Seiko Sho | Fluid control system for power shovel |
US7389640B2 (en) * | 2002-04-10 | 2008-06-24 | Luk Lamellen Und Kupplungsbau Beteiligungs Kg | Hydraulic system and automatic transmission |
US20090077958A1 (en) * | 2005-03-14 | 2009-03-26 | Masaaki Yamashita | Hydraulic Circuit Structure of Work Vehicle |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8483917B2 (en) * | 2011-08-08 | 2013-07-09 | Komatsu Ltd. | Backhoe loader |
Also Published As
Publication number | Publication date |
---|---|
CA2735253C (en) | 2013-12-31 |
JP5368752B2 (en) | 2013-12-18 |
WO2010026848A1 (en) | 2010-03-11 |
CA2735253A1 (en) | 2010-03-11 |
US8713931B2 (en) | 2014-05-06 |
JP2010060027A (en) | 2010-03-18 |
US20110168283A1 (en) | 2011-07-14 |
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