JP2005067327A - Agricultural tractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an agricultural tractor provided with an external hydraulic pressure taking out device of the tractor capable of more simply arranging a hydraulic hose connecting tool for taking out external hydraulic pressure and taking out a hydraulic hose to the outside as compared with a conventional tractor without bringing the hydraulic hose into contact with crops and obstacles, etc. <P>SOLUTION: In a rear part of a vehicle body of the tractor, a gear pump 62 for generating pressure oil by operating by engine power, a hydraulic cylinder 66 for driving of a lift arm 37, and a control valve 60 for performing a feeding control of pressure oil to be fed to the hydraulic cylinder 66 are provided. At a front end part of a floor 5 located at a substantial center part of the vehicle body, an external taking out part 51 is provided to feed the pressure oil from the gear pump 62 to an external working machine 18 via the control valve 60. A hydraulic pipe 50 for connecting the control valve 60 and the external taking out part 51 is arranged through a lower part of the floor 5 and a space between left and right machine frames 2 of the vehicle body. The hydraulic pipe 50 and a hydraulic pipe 55 for a return oil from a bucket 18 are adjacently arranged. End parts of each of the pipes 50 and 55 can be connected by an attachable/detachable U-shaped pipe 53. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an external hydraulic pressure take-out device for an agricultural tractor.

Conventionally, as shown in FIG. 7 (FIG. 1 of JP-A-7-117586), an external hydraulic pressure take-out device for an agricultural tractor is provided with an operation lever 102 and a control valve 105 on the side of the driver's seat 101. In the agricultural tractor in which a floor 103 is provided at the front lower part of 101, a hood 104 is protruded upward on the front side of the floor 103, and an oil passage in the vertical direction is opened in the hood 104. 106 is attached, and between the lower end surface of the hydraulic hose connector 106 and the control valve 105, high-pressure hoses 107, 107. . And an open / close plug 108, 108. . There is known an external hydraulic pressure take-out device with an attached.
Japanese Unexamined Patent Publication No. 7-117586

   In the agricultural tractor external hydraulic take-out device, the oil path of the hydraulic hose coupling 106 for taking out the external hydraulic pressure is provided on the floor 103 immediately after the front wheel in the vertical direction, so that even a wheel-based short tractor contacts the front wheel. There is an advantage that the external take-out hose can be easily attached / detached without the need of

  However, since the tractor described in the above publication assumes a configuration in which a lifting cylinder and a three-point link at the front of the vehicle body are detachable, for example, an external work such as a bucket for soil removal in front of an agricultural tractor. When installing the machine, the control valve 105, the high-pressure hose 107, and the hydraulic hose connector 106 need to be attached and detached, which is a troublesome operation.

  In addition, when the external hydraulic pressure take-out device is configured to be permanently installed in the vehicle body, there is a possibility that the high-pressure hose 107, the coupling tool 106, etc. may be caught on a crop or contact with an obstacle to damage both or one of them. .

  An object of the present invention is to provide an external hydraulic take-out device in which the arrangement of the hydraulic hose coupler for taking out the external hydraulic pressure and the external take-out of the hydraulic hose can be performed more easily than before, but the hydraulic hose or the like does not contact crops or obstacles. To provide agricultural tractors.

The object of the present invention is achieved by the following means.
According to the first aspect of the present invention, in an agricultural tractor driven by the engine 12 and having the cockpit seat 8 disposed on the vehicle body including the left and right machine casings 2 and 2, the vehicle body of the tractor is operated by engine power. A hydraulic pump 66 for generating pressure oil, a hydraulic cylinder 66 for driving the lift arm 37, a control valve 60 for controlling the supply of pressure oil to the hydraulic cylinder 66, and a floor located substantially in the center of the vehicle body 5 is provided with an external take-out portion 51 for sending pressure oil from the gear pump 62 to the external work machine 18 via the control valve 60, and connecting the control valve 60 and the external take-out portion 51 to the front end portion. An agricultural tractor in which piping 50 is routed below the floor 5 and between the left and right machine casings 2.

  According to the second aspect of the present invention, the hydraulic piping 50 connected to the external take-out portion 51 is arranged adjacent to each other in a pair with the hydraulic piping 55 for return oil from an external work machine (for example, the bucket 18 or the mower). 2. The agricultural tractor according to claim 1, wherein the hydraulic pipe connected to the section 51 and the end of the return oil hydraulic pipe 55 are connectable by a detachable U-shaped pipe 53.

  According to a third aspect of the present invention, the switching operation means 57 for switching between oil feeding to the drive hydraulic cylinder 66 of the lift arm 37 and oil feeding to the external work machine is disposed in the vicinity of the cockpit 8. Agricultural tractor.

  According to the first aspect of the present invention, since the hydraulic pipe 50 connected to the external take-out portion 51 for taking out the hydraulic pressure for the external work machine is arranged below the floor 5 and between the left and right machine frames 2, the external hydraulic take-out When the apparatus is permanently installed in the vehicle body, the hydraulic pipe 50 connecting the control valve 60 and the external take-out portion 51 is not suitable for crops or obstacles during operation as compared with the conventional configuration in which a high-pressure hose is routed on the side of the vehicle body. There is no interference with objects, and both or one side is not damaged.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the end of the hydraulic pipe 50 connected to the external take-out portion 51 and the return oil hydraulic pipe 55 is detachable U-shaped pipe. Since connection is possible at 53, the external extraction part 51 may be closed using the U-shaped pipe 53 when unnecessary.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, the work machine such as the rotary 29 such as the drive hydraulic cylinder 66 of the lift arm 37 and the external work machine (bucket 18, mower). Since the switching operation means 57 for switching the oil supply to the vehicle is disposed in the vicinity of the cockpit 8, the switching operation means 57 is easy to operate.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a side view of a tractor according to an embodiment of the present invention, and FIG. 2 shows a diagram showing a traveling transmission system of the tractor of FIG.

  The conventionally known tractor 1 has an engine 12 mounted on the front portion of the machine casing 2 and transmits the rotational power of the engine 12 to the transmission 4 in the transmission case 3. The opening degree of the throttle valve of the engine 12 changes according to the depression amount of the accelerator pedal 6 provided on the floor 5, and the rotational speed of the power shaft input to the transmission 4 increases or decreases.

  Further, above the floor 5, a steering handle 7, a cockpit 8, a lifting lever 9 for the rotary 29, a clutch pedal (not shown), a main transmission operation lever, an auxiliary transmission lever, a pair of left and right brake pedals, and the like are provided. ing. The steering handle 7 is supported by the handle post 13. Further, a soil removal bucket 18 is provided in front of the machine casing 2. The bucket 18 is lifted and lowered by the boom cylinder 24 together with the boom 23, and the bucket 18 can swing the bucket 18 in the vertical direction.

  The rotational power finally decelerated by the transmission 4 in the transmission case 3 is transmitted to the left and right rear wheels 10 and 10. A front wheel drive shaft (not shown) for driving the front wheels 11 is supported at the front portion of the transmission case 3.

  The transmission 4 includes a transmission that is a hydrostatic continuously variable transmission (hereinafter referred to as an HST main transmission 17) serving as a main transmission and a gear-type sub-transmission 19, and each shift lever ( (Not shown) is configured to move forward and backward or select an appropriate shift position. As shown in the diagram of the traveling transmission system in FIG. 2, the auxiliary transmission 19 includes a plurality of high-speed gears and low-speed gears on the auxiliary transmission drive shaft provided on the lower side of the HST type main transmission 17. A sub-shift output shaft having a gear stage and having a gear meshing with any one of the gears is provided.

  In the diagram of FIG. 2, the rotational power of the engine 12 is transmitted to the main clutch 15 that is operated to turn on and off the transmission power by the clutch pedal, and then sequentially to the HST main transmission 17 and the subtransmission 19. The rear wheels 10 and 10 are driven via the rear wheel differential device 20 and the final reduction gear mechanism 21. Further, the front wheels 11 and 11 are routed through a front wheel rotation switching unit 25 for branching the power from the transmission power of the rear wheel differential device 20 to switch between front wheel acceleration or constant speed four-wheel drive consisting of a gear transmission system, and further driving the front wheels. The power of either a normal four-wheel drive system or a speed-increasing four-wheel drive system is transmitted from the shaft 14 to the front wheels 11 and 11 through the front wheel differential device 27.

  When pressure oil is supplied to the hydraulic cylinder 66 for raising and lowering the work machine provided at the rear part of the mission case 3, the piston 35 is operated, and the piston 35 rotates lift arms 37 and 37 on both the left and right sides of the hydraulic cylinder 66. Let Lift rods 39, 39 are provided between the lift arms 37, 37 and the lower links 38, 38, and a rotary 29 is connected to the rear ends of the top link (not shown) and the lower links 38, 38. When the arms 37 and 37 are rotated, the rotary 29 moves up and down.

Next, a hydraulic circuit for raising and lowering the rotary 29 of the tractor, operating the bucket 18 and the like (elevating and lowering) and operating the power steering hydraulic cylinder 83 will be described with reference to FIG.
The gear pump 62 sucks up the oil in the transmission case (oil tank) 3 by driving the engine 12, and uses this as pressure oil to operate the hydraulic circuit of the operating system (bucket 18, rotary 29) and the traveling hydraulic circuit (for HST). It is configured to branch into

  The operation system hydraulic circuit such as the operation of the bucket 18 (elevating / lowering) and the raising / lowering of the rotary 29 has a flow dividing valve 63 connected to the upstream side of the circuit inside the control valve 60, and the flow dividing valve 63 via a manual switching valve 64. Thus, for example, a lifting hydraulic cylinder 66 of the rotary 29 is connected. By providing a suction filter 67 at the inlet from the oil tank (transmission case) 3 of the operating system hydraulic circuit of the rotary 29, the bucket 18, the mower (often provided at the front end portion or the lower portion of the machine frame 2). The clogging of the diversion valve 63 with dust can be prevented in advance. A relief valve 71 is provided in an oil passage 69 branched from an oil passage 68 on the front side of the diversion valve 63, and is connected to a return passage 72 from the manual switching valve 64 on the downstream side. When the hydraulic pressure from the hydraulic pump 62 increases excessively, the pressure oil is returned to the oil tank 3 via the relief valve 71.

  In addition, a throttle valve 76 is provided in the control flow oil passage 75 in order to supply pressure oil having a constant hydraulic pressure to the power steering hydraulic cylinder 83 from the diversion valve 63, and the control valve is controlled via the throttle valve 76. Pressure oil of a constant pressure is preferentially sent to the fully hydraulic steering device 82, and the power steering hydraulic cylinder 83 is operated. Further, an excess oil passage 74 through which excess oil flows is connected to another oil outlet of the diversion valve 63. These oil passages 74 can be connected to an external extraction metal 53 that can be attached and detached from the outside of the hydraulic circuit. Pressure oil is supplied from the external take-out metal 53 to a hydraulic device 79 of an external work machine such as the bucket 18.

  In the hydraulic circuit having the above-described configuration, when the flow dividing valve 63 is in the illustrated position, the pressure oil pressurized by the pump 62 that has been brought to a constant pressure via the throttle valve 76 passes through the all-hydraulic steering device 82. It is sent to the power steering cylinder 83. The pressure oil discharged from the fully hydraulic steering device 82 is used for the operation of the PTO clutch 80 through the PTO valve 77.

  When the diverter valve 63 shifts to the right side of the drawing against the spring 86 due to the back pressure on the lower side of the circuit, the excess oil together with the control spring oil for operating the hydraulic cylinder 83 for power steering passes through the external take-out metal 53. Then, the pressure oil can be sent to the rotary 29 elevating cylinder 66 side through the manual switching valve 64 and the slow return circuit 65. In the manual switching valve 64, the rotary 29 can be placed in a neutral position or raised or lowered to a raised or lowered position according to an operation position by a manual lever 85.

  The transmission for the tractor of this embodiment includes a hydrostatic transmission (HST) in which a conventionally known variable displacement hydraulic pump 91 and a hydraulic motor 92 are connected by a hydraulic circuit in which oil circulates in a closed circuit. .

4 is a tractor plan view showing the arrangement of the control valve 60 and the hydraulic piping of the hydraulic circuit shown in FIG. 3, and FIG. 5 is a partial front view of the tractor.
The hydraulic piping 50 was routed directly below the floor 5 and in the space above the frame of the machine casing 2. Then, the external take-out portion 51 of the external hydraulic device 79 for using pressure oil in the bucket 18 and the return portion 52 from the external hydraulic device 79 are connected by a U-shaped pipe 53 (external take-out metal), and when using external hydraulic pressure, the pipe 53 was removed for use. Two hydraulic pipes 50 and 55, which are composed of a hydraulic pipe 50 from the control valve 60 to the external hydraulic pressure take-out part 51 and a hydraulic pipe 55 from the return part 52 to the control valve 60, are arranged in parallel and directly below the floor 5. If the arrangement is made without a joint, the shortest arrangement route can be obtained and the cost can be reduced. Further, even if an external working machine such as a mower is installed below the machine casing 2, it does not interfere with these external working machines. In addition, the above-described hydraulic piping system has an advantage that there is no catching or contact with crops or obstacles when an external hydraulic pressure take-out device is permanently installed.

  Further, when taking out the hydraulic oil sent out from the gear pump 62 as an external hydraulic pressure, the gear pump 62 is provided on either side in the left-right direction with respect to the forward direction of the machine frame 2, while the external hydraulic pressure take-out part 51 and the return part 52 is provided on the other side in the left-right direction of the machine casing 2, and the hydraulic pipes 50, 55 that cross from one side of the machine casing 2 to the other side are positioned above the machine casing 2. Therefore, the reinforcement frame 2a guards the pipes 50 and 55, so that the hydraulic pipes 50 and 55 that run in the left-right direction can be prevented from being damaged.

  Further, the external hydraulic pressure take-out part 51 is provided in front of the step part 5a on the right side of the floor 5, and the vicinity of the floor step part 5a of the hydraulic pipe 50 communicating with the external hydraulic pressure take-out part 51 is directed obliquely forward in plan view. In addition, it is possible to easily connect the loader connecting hydraulic pipe and the external hydraulic pressure take-out part 51 when the external hydraulic device 79 is used for a loader constituted by the bucket 18 or the like.

  In addition, the connecting portions 51 and 52 between the external hydraulic pressure take-out portion 51 and the hydraulic piping for connection to the bucket 18 are positioned so as not to protrude forward from the front end surface of the reinforcement frame 2a integrated with the machine frame 2 projecting outward in the left and right directions. By providing, the possibility that the pipe connecting portions 51 and 52 may be hit by an obstacle or the like is reduced. Furthermore, since the U-shaped pipe 53 is located on the reinforcing frame 2a below a floor (not shown) having a size larger than the frame 2a, the U-shaped pipe 53 is not likely to be damaged by hitting an obstacle or the like.

  A switching operation means portion 57 for turning on / off the external oil pressure extraction oil passage is provided on the flange portion (the upper surface of the control valve 60) of the hydraulic piping 50 for taking out the external hydraulic pressure. Enabled manual operation to turn on / off.

  As shown in the partial side view of the front part of the tractor in FIG. 6, a support 93 is provided on the right front side of the machine frame 2, and a control lever 94 for operating an external work machine such as a bucket 18 or a mower is provided on the upper part of the support 93. Provide. Further, an operation link for the external work machine is arranged along the support 93.

  The present invention can be used for an agricultural tractor provided with an external hydraulic pressure take-out device.

It is a side view of the tractor of an embodiment of the invention. It is a drive mechanism figure of the tractor of FIG. It is a hydraulic circuit diagram of the tractor of FIG. It is a partial top view of the tractor of FIG. It is a partial front view of the tractor of FIG. In the partial side view of the front part of the tractor in FIG. It is a schematic side view of the tractor of a prior art.

Explanation of symbols

1 Tractor 2 Machine frame 2a Reinforcement frame 3 Mission case (oil tank)
DESCRIPTION OF SYMBOLS 4 Transmission 5 Floor 5a Step part 6 Accelerator pedal 7 Steering handle 8 Control seat 9 Rotary lift lever 10 Rear wheel 11 Front wheel 12 Engine 13 Handle post 14 Front wheel drive shaft 15 Main clutch 17 HST type main transmission 18 External work machine ( (Bucket) 19 Gear type auxiliary transmission 20 Rear wheel differential device 21 Final reduction gear mechanism 22 Bucket cylinder 23 Boom 24 Boom cylinder 25 Front wheel rotation switching unit 27 Front wheel differential device 29 Rotary 35 Piston 37 Lift arm 38 Lower link 39 Lift rod 50, 55 Hydraulic piping 51 External hydraulic pressure extraction part (piping connection part)
52 Return part (Piping connection part) 53 U-shaped pipe (External metal)
57 switching operation means 60 control valve 62 gear pump 63 diversion valve 64 manual switching valve 65 slow return circuit 66 hydraulic cylinder 67 suction filter 68, 69 oil passage 71 relief valve 72 return path 74 surplus flow oil path 75 control flow oil path 76 throttle valve 77 PTO valve 79 External hydraulic device 80 PTO clutch 82 Full hydraulic steering device 83 Power steering cylinder 85 Manual lever 86 Spring 91 Hydraulic pump 92 Hydraulic motor 93 Strut 94 Control lever

Claims (3)

In an agricultural tractor driven by an engine 12 and having a cockpit 8 disposed on a vehicle body including left and right machine casings 2 and 2,
A gear pump 62 that operates with engine power to generate pressure oil, a drive hydraulic cylinder 66 for the lift arm 37, and a control valve 60 that controls the supply of pressure oil to be sent to the hydraulic cylinder 66 are provided at the rear of the vehicle body. With
Provided at the front end portion of the floor 5 located substantially in the center of the vehicle body is an external take-out portion 51 for sending pressure oil from the gear pump 62 to the external work machine 18 via the control valve 60;
An agricultural tractor characterized in that a hydraulic pipe 50 connecting the control valve 60 and the external take-out portion 51 is routed below the floor 5 and between the left and right machine casings 2.   A hydraulic pipe 50 connected to the external take-out section 51 is disposed adjacent to each other in a pair with a return oil hydraulic pipe 55 from the external work machine 18, and a hydraulic pipe 50 connected to the external take-out section 51 and a return oil hydraulic pipe 55 are connected to each other. The agricultural tractor according to claim 1, wherein the end portion is connectable by a detachable U-shaped pipe 53. The switching operation means (57) for switching between oil supply to the drive hydraulic cylinder (66) of the lift arm (37) and oil supply to the external work machine (18) is disposed in the vicinity of the cockpit (8). Agricultural tractor.

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