JP2008031787A - Work vehicle - Google Patents

Abstract

Provided is a work vehicle in which a lift arm can be actuated when necessary, and a back-side external work machine is detachably mounted so that the lift arm is not inadvertently actuated to ensure the safety of an operator. thing.
When a work is performed with a backhoe attached, the lift arm is left as it is although the three-point link mechanism is removed from the machine body. If the lift arm is operated unexpectedly, various members may be damaged. . Therefore, the lower side solenoid 62a is always turned on while the operator is working with the seat 8 facing backward, and even if the raising side solenoid 61a is turned on, the hydraulic oil does not flow into the elevating cylinder 41 and the lift arm 38 is moved. Do not raise.
[Selection] Figure 10

Description

  The present invention relates to a work vehicle in which a back side external work machine is detachably mounted.

Conventionally, among work vehicles such as agricultural tractors, there is a work vehicle in which a front-side external work machine and a back-side external work machine (for example, a backhoe) can be freely mounted.
In such a work vehicle, the operator can change the seat forward and backward so that the operator can control the work vehicle while sitting on the rear seat of the work vehicle, and only the work performed by the operator sitting on the forward seat. Instead, the user can perform the work by sitting on the rearward seat or the forward-facing seat with the rearward direction changed.

  In this type of work vehicle, the backhoe is removed from the rear part of the machine body, and a so-called three-point link mechanism including a top link and a pair of lower links, for example, is attached. Can be attached to the fuselage to perform tilling work on the field.

  The so-called three-point link mechanism is raised and lowered by raising and lowering a lift arm provided at the rear of the machine body. However, since the lift arm is not removed even when a backhoe is attached, the operator sits on the back seat on the work vehicle. However, when the lift arm is raised when operating the backhoe, not only does it interfere with the operation, but the lift arm may hit various members and damage the members.

As a countermeasure for this, the invention described in Japanese Patent No. 3651929 is configured to provide an operation tool capable of switching oil supplied from a hydraulic pump to a lift arm lifting / lowering hydraulic device and a backhoe operating hydraulic circuit.
Japanese Patent No. 36552929

  In the invention described in Patent Document 1, when operating the backhoe, the operator closes the hydraulic circuit that supplies oil to the lift arm lifting hydraulic cylinder with the operating tool to ensure the safety of the operator. Since this is due to the operation tool, the lift arm may be operated unexpectedly when the operation tool is erroneously operated by the operator or unexpectedly collides with another object.

  Therefore, an object of the present invention is to allow the lift arm to be operated when necessary, and to attach and detach the back-side external work machine that prevents the lift arm from being inadvertently operated for the safety of the operator. It is to provide an attached work vehicle.

The problems of the present invention are solved by the following means.
According to the first aspect of the present invention, the work device (10, 9) can be mounted on the front and rear of the machine body (2) having front and rear wheels (6a, 6b), respectively, and the work device (2) on the rear of the machine body (2) ( 9) Instead of 9), the work equipment (35) can be mounted via a three-point link mechanism (36, 37) and lifting lift arm (38), and the operator can change the direction forward and backward in the cockpit Or, in a work vehicle provided with two front and rear seats (8, 8 '), a hydraulic cylinder (41) for raising and lowering the lifting lift arm (38) and a control valve for controlling the hydraulic pressure of the hydraulic cylinder (41) (61, 62), the actuator (61a, 62a) for operating the control valve (61, 62), and the seat (8) are in the rearward posture, the lifting lift arm (38) is lowered in the direction of lowering. Actuator (62a) is a work vehicle provided with a control device (100) that permits the actuating (62a) but does not allow the actuating actuator (61a) to be actuated in the direction of raising the lifting lift arm (38).

  The invention according to claim 2 is provided with a detecting means (70) for detecting the raising / lowering position of the lifting / lowering lift arm (38), and the detecting means (70) exceeds the raising / lowering position set by the lifting / lowering lift arm (38). The work according to claim 1, further comprising a control device (100) for operating the actuator (62a) in a direction to lower the lift arm (38) when the lift arm (38) is detected to move in the upward direction. It is a vehicle.

  According to the first aspect of the present invention, although the three-point link mechanism is removed during the backhoe work, the lift arm (38) is left as it is, thereby preventing the lift arm (38) from operating unexpectedly. Can do.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the position of the lift arm (38) is always known by the lift arm detecting means (70) for raising and lowering. When the detecting means (70) detects that (38) has moved in the upward direction, the actuator (62a) is always operated by moving the actuator (62a) in the direction in which the lifting lift arm (38) is lowered. There is no need to energize.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a side view of the tractor of this embodiment. 2 shows a plan view of the transmission system in the transmission of the tractor of FIG. 1, FIG. 3 shows a plan view of the left rear axle portion, and FIG. 4 shows a left side view of the transmission system in the transmission. In this specification, the left and right directions in the traveling direction of the tractor are referred to as left and right, respectively, and the front and rear directions in the traveling direction are referred to as front and rear, respectively.

  A conventionally known tractor 1 transmits the rotational power of an engine (not shown) mounted on an airframe 2 to a transmission in a mission case 3. The throttle valve opening of the engine (not shown) changes according to the amount of depression of the accelerator pedal provided on the floor 5, and the rotational speed of the power shaft input to the transmission increases or decreases to drive the rear wheel 6b. Let The front wheel 6a is rotated by the driving force of the rear wheel 6b.

  The transmission system shown in FIG. 2 includes a main clutch 80, a forward / reverse switching device 81 (81F, 81R), a main transmission 82, and an auxiliary transmission 83 in the transmission case 3, and drives by shifting the rotation of the engine. The shaft 84 is transmitted to the rear wheel differential device 85 and the front wheel differential device 86 to drive the rear wheel 6b and the front wheel 6a.

  As shown in FIG. 3, the left and right rear axles 87 interlocking with the rear wheel 6b are respectively provided with brake devices 88L and 88R (only the left side is shown in FIG. 3), and brake arms 89L and 89R (89R is a figure). It is configured to be braked by a swinging operation (not shown). As shown in FIG. 4, the brake arms 89L and 89R switch the braking side of brake control valves 90L and 90R (90R not shown) provided on the left and right outer surfaces of the transmission case 3, respectively. The brake pistons 91L and 91R (91R not shown) provided integrally with the box are configured to swing to the braking side by the extension operation. The non-braking side return is performed by an elastic return spring (not shown). Since the brake arms 89L and 89R are mechanically linked to a brake pedal (not shown), the left and right rear wheels 6b can be braked independently by pedal operation.

  Above the floor 5, a steering handle 7, a cockpit seat 8, a backhoe 9, a front loader 10, 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. . The steering handle 7 is supported by a handle post 12.

  A configuration example in which the seat 8 can rotate forward and backward (dotted line) as the cockpit seat 8 will be described. The front loader 10 can be operated when seated on the forward-facing seat 8, and the backhoe 9 can be operated when seated on the rear-facing seat 8 (dotted line). Although not shown, the seat 8 may be configured to include two forward and backward seats 8.

  FIG. 5A shows a side view of a sheet portion having a reversible structure according to an embodiment. A rotation support member 21 provided on the backrest is inserted into a pole 20a erected in the vertical direction with respect to the airframe behind the backrest of the seat 8. As shown in the enlarged view of FIG. 5B in FIG. 5B, the rotation support member 21 is provided with a through hole 21a for inserting the pole 20a in the vertical direction, and the pole 20a is inserted into the through hole 21a. By doing so, the sheet 8 is rotatably supported. That is, a cylindrical support portion 20d fixed to the airframe is provided at the lower end of the pole 20a, and longitudinal grooves 20c and 20b are formed in the front and rear of the inner wall surface of the cylindrical support portion 20d. Then, when the seat 21 is inserted from above the pole 20 and the pin 21b fixed to the lower portion of the rotation support member 21 is fitted into the vertical groove 20b of the tube support portion 20d, the seat 8 is disposed forward and the pin 21b is placed in the tube support portion. When fitted in the vertical groove 20c of 20d, the seat 8 is configured to be disposed rearward.

  Here, a pair of sheet detection sensors (not shown) are provided at positions opposed to the inner wall surface of the cylinder support portion 20d. In FIG. 5A, the sheet 8 before inversion is a sheet detection sensor 23 provided on the rotation support member 21 and one sheet detection sensor (not shown) provided on the inner wall surface of the tube support portion 20d. When it is detected that they are close to each other, the sheet 8 faces forward, and the sheet detection sensor 23 provided on the rotation support member 21 and another sheet detection sensor (not shown) provided on the inner wall surface of the tube support portion 20d. Can detect that the sheet 8 is reversed backward.

  FIG. 6 shows a side view of an example of the rear portion of the tractor 1 with the backhoe 9 removed and the tilling device 35 attached to the rear of the machine body. The tillage device 35 is attached to the machine body by a so-called three-point link mechanism 30 including a top link 36 and a pair of lower links 37. Each of the lower links 37 of the pair of lower links 37 is connected to each other via a lift arm 38 and a lift rod 39, and the pair of lift arms 38 are moved up and down by an elevating cylinder 41, thereby lowering the lower link 37 via the lift rod 39. The link 37 moves up and down so that the tilling device 35 can be moved up and down.

Next, an operation mechanism for the operation of the backhoe 9 of the tractor 1 (up and down movement of the arm part and up and down movement and bucket rotation, and arm rotation movement) and the operation of the front loader 10 (up and down movement and up and down movement) will be described with reference to FIG. The hydraulic circuit for the operating mechanism will be described with reference to FIG.
The backhoe 9 is provided with a bucket 44 for earth removal. The bucket 44 is connected to a first arm 45, and a second arm 46 is connected to the first arm 45. The bucket 44 can swing up and down by a bucket cylinder 48 around the rotation center 44a, the first arm 45 is raised and lowered by a first arm cylinder 49, and the second arm 46 is a second arm. The cylinder 50 moves up and down.

  Further, the bucket 17 of the front loader 10 is connected to the first boom 52 around the rotation center 17 a, and the second boom 53 is connected to the first boom 52. The bucket 17 can swing up and down by a bucket cylinder 55, and the second boom 53 is raised and lowered by the second boom cylinder 54.

  Further, as shown in FIG. 7, a main gear pump 56 and a sub gear pump 57 are provided. The main gear pump 56 sucks up oil in the transmission case (oil tank) 3 and uses it as pressure oil to work equipment (front loader 10, backhoe). 9 and a working device connected to the rear part of the work vehicle main body such as the tillage device 35 by the three-point link mechanism 30) operation system hydraulic circuit, forward / reverse clutches 81F and 81R, and other traveling system hydraulic circuits for rear wheel brake operation It has a structure that branches.

The operation of the front loader 10 (lifting and moving up and down) is always in an operating state by the operation of the gear pump 56. Further, the lifting / lowering oil path L2 of the backhoe 9 including the lifting / lowering oil path L1 and the outrigger 40 of the working device connected by the three-point link mechanism 30 such as the tilling device 35 is a switching valve 59, and either oil The road is selectively switched. Switching of the oil passages L1 and L2 by the switching valve 59 automatically opens the oil passage L2 for raising and lowering the backhoe 9 when the seat reversal detection sensor 23 detects that the seat 8 has been reversed. The drive oil path L1 of the point link mechanism 30 is closed.
Accordingly, when it is determined whether the backhoe 9 or the three-point link mechanism 30 is to be attached to the rear of the machine body 2, the switching valve 59 is switched in advance in a direction that matches that.
These control flows are shown in FIG.

  The proportional control valve 60 for the raising / lowering cylinder 41 such as the tillage device 35 includes a rising proportional control valve composed of a pressure regulating valve 61 and a pilot spool 66, and a descending proportional control composed of a pressure control valve 62 and a pilot spool 67. It consists of a control valve and the like. When the proportional control valve 60 is neutral, both the proportional solenoid 61a of the lift side pressure regulating valve 61 of the lift arm 38 and the proportional solenoid 62a of the down side pressure regulating valve 62 are not energized, so that the hydraulic oil flowing from the pump 56 causes the compensator 63 to flow. Return to the oil tank 3 for the entire amount. The hydraulic oil in the elevating cylinder 41 does not flow out because it is blocked by the check valve 64 or the like.

  When there is an instruction to raise the lift arm 38, first, a current according to the condition flows from the controller 100 (FIG. 9) to the proportional solenoid 61a of the raising side pressure regulating valve 61. The pilot pressure corresponding to the current is increased, the pilot spool 66 is operated, and the hydraulic oil from the hydraulic pump 56 flows out to the lifting cylinder 41, so that the lift arm 38 is raised. As the magnitude of the current value increases, the lifting speed of the lift arm 38 increases accordingly. The surplus oil passes through the compensator 63 and returns to the oil tank 3.

  When there is an instruction to lower the lift arm 38, first, a current corresponding to the condition flows from the controller 100 to the proportional solenoid 62 a of the lower pressure regulating valve 62. The pilot pressure corresponding to the current is lowered to operate the pilot spool 67, the hydraulic oil in the elevating cylinder 41 flows out to the oil tank 3, and the lift arm 38 is lowered. Also in this case, the descending speed of the lift arm 38 changes according to the magnitude of the current value. Further, the hydraulic oil from the oil pump 56 passes through the compensator 63 and returns to the oil tank 3.

  The hydraulic circuit shown in FIG. 7 includes not only the hydraulic circuit of the lift cylinder 41 but also a power steering unit for turning the steering wheel, a reverse valve, a PTO clutch, and a shunt valve for the oil path for operating the rear wheel brake. The pressure oil is sent via.

  With the tractor having the above configuration, the three-point link mechanism 30 is removed from the airframe during the work performed with the backhoe 9 attached, but the lift arm 38 remains as it is, and various members are damaged if the lift arm 38 is unexpectedly operated. There is a risk of causing. Therefore, as shown in the control block of FIG. 9 and the flowchart of FIG. 10, the lift arm position sensor 70 that detects the position of the lift arm 38 is activated by the lift arm 38 according to the operating position of the work implement lifting lever (not shown). When it is detected that it is at the predetermined lowered position, the lowering solenoid 62a outputs. Further, the seat 8 is disposed rearward by the seat orientation sensor 23 that detects that the lift arm 38 is in a predetermined raised position in accordance with the operation position of the work implement elevating lever and simultaneously detects that the seat 8 is rearward. If it is detected, the raising solenoid 61a is prevented from outputting.

  Thus, the lower solenoid 62a is always turned on when the operator sits on the seat 8 facing backward and performs the backhoe work, and the lift arm 38 is not raised even if the raise solenoid 61a is turned on at this time. To.

  Further, when the operator sits on the back-facing seat 8 and performs the backhoe work, the detection value of the sensor 70 for detecting the position of the lift arm 38 is always detected, and the detection value is equal to or higher than the set value, A configuration may be adopted in which the solenoid 62a of the lowering pressure control valve 62 is turned on when it is detected that the arm 38 has moved in the upward direction from the set value. In this case, it is not necessary to energize the solenoid 62a of the lowering pressure control valve 62 at all times.

  Further, every time it is detected that the lift arm 38 moves in the upward direction as described above, a history of each sensor, valve output value, etc. is left in the controller 100 for storing the failure mode. At that time, the operator can be alerted more by notifying the operator of the above-mentioned state by an alarm sound or a display screen (light).

  In the control block diagram of FIG. 11 and the flow of FIG. 12, when the operator works while sitting on the seat 8 facing backward, if the operator does not forget to release the parking lever or parking pedal (not shown), the parking lever or parking The brake disc of the pedal may be worn abnormally.

  Therefore, in order to prevent forgetting to release the parking lever or the parking pedal, the display monitor 73 (see FIG. 13) is arranged at a position where the operator can see even if the operator is seated on the seat 8 facing backwards. Alternatively, when the parking pedal is in an operating state, it is configured to output a lighting signal of the monitor 73, and the aircraft is located at a position where it can be operated during backward operation such as the forward / reverse switching lever 93 near the steering wheel (for example, on the fender). The controller 100 may be provided with a control circuit for operating the forward clutch actuating solenoid 74a or the reverse clutch actuating solenoid 74b by disabling the operation of the forward / reverse switch 94 for moving forward and backward at low speed.

  When there is no lighting signal of the display monitor 73, that is, when the parking lever or the parking pedal is not in operation, the operation of the forward / reverse switching lever 93 or the forward / reverse switch 94 is accepted to advance or reverse the aircraft. However, when the forward / reverse switching lever 93 is used, the seat direction is forward, and when the forward / backward switch 94 is operated, the seat direction is backward. It is.

  FIG. 13 shows an installation example of the display monitor 73. As shown in the perspective view of FIG. 13 (a), a pillar cover 75 is installed to attach a display monitor 73 dedicated to the rear of the fuselage to the side of the rear column (FOPS (falling object protect structure)) frame 13 of the cab. The display monitor 73 is attached to the window 75a of the pillar cover 75. As shown in the horizontal sectional view of FIG. 13B, the pillar cover can be attached to the support column (FOPS frame) 13 via the rubber 77 to reduce the vibration to the electrical component (particularly the filament).

  Further, as shown in the side view of the cockpit portion of FIG. 14, rain water may not enter the pillar cover 75 by providing the pillar cover 75 on the entire support column reaching the sun visor (roof) 78.

  Further, as shown in the side view of FIG. 15 (a), the rear view of FIG. 15 (b), and the sectional view taken along the line AA of FIG. 15 (a) of FIG. When the operator sits on the seat 8 facing backwards sometimes, the left and right lateral frame 79a and the front and rear frames 79b of the airframe are placed on the operator's head, and a sun visor (roof) 78 is mounted on the frames 79a and 79b. The operator's protection function by falling objects may be maintained.

  The tractor of the present invention can be used as a machine for various works other than farm work.

It is a right view of the tractor of the Example of this invention. It is a top view of the transmission system in the transmission of the tractor of FIG. It is a top view of the rear axle part of the left side of the tractor of FIG. It is a left view of the transmission system in the transmission of the tractor of FIG. It is the side view (FIG. 5 (a)) of the sheet | seat part of other Examples of the tractor of FIG. 1, and the partially expanded perspective view (FIG.5 (b)) of FIG. 5 (a). It is a principal part side view of the rear part of a tractor at the time of removing a backhoe and mounting a tillage apparatus in the body rear. FIG. 2 is a hydraulic circuit diagram for an operating mechanism for operating the backhoe, the three-point link mechanism, and the front loader of the tractor of FIG. 1. It is a control flow figure of other examples at the time of performing light work using the backhoe of the tractor of Drawing 1. FIG. 2 is a control block diagram for ensuring work safety when seated on a backward-facing seat of the tractor of FIG. 1. 10 is a flowchart of control for ensuring work safety in FIG. 9. FIG. 2 is a control block diagram for forward and backward traveling while sitting on a rearward seat of the tractor of FIG. 1. It is a flowchart of the traveling control of FIG. It is an assembly figure (Fig.13 (a)) of the attachment structure of the rear display monitor of the tractor of FIG. 1, and a horizontal sectional view (FIG.13 (b)) of the said attachment structure. It is a side view of the cockpit part of the modification of the attachment structure of the rear display monitor of the tractor of FIG. A side view (FIG. 15 (a)), a rear view (FIG. 15 (b)), and a cross-sectional view taken along line AA in FIG. 15 (a) (FIG. 15 (c)) of the cockpit portion of the tractor of FIG. It is.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tractor 2 Airframe 3 Mission case 5 Floor 6a Front wheel 6b Rear wheel 7 Steering handle 8 Driver's seat 9 Backhoe 10 Front loader 12 Handle post 13 Post 17 Bucket 17a Rotation center 20a Pole 20b, 20c Vertical groove 20d Tube support part 21 Rotation Support member 21a Through hole 21b Pin 23 Sheet detection sensor 30 Three-point link mechanism 35 Tillage device 36 Top link 37 Lower link 38 Lift arm 39 Lift rod 40 Outrigger 41 Lifting cylinder 44 Bucket 44a Center of rotation 45 First arm 46 Second arm 48 bucket cylinder 49 first arm cylinder 50 second arm cylinder 52 first boom 53 second boom 54 boom cylinder 55 bucket cylinder 56 main gear pump 57 sub gear pump 5 Switching valve 60 Proportional control valve 61 Raising side pressure control valve 61a Raising side solenoid 62 Decreasing side pressure control valve 62a Lowering side solenoid 63 Compensator 64 Check valve 66 Raising main valve 67 Lowering main valve 73 Display monitor 74a Advance side clutch operating solenoid 74b Reverse-side clutch actuating solenoid 75 Pillar cover 75a Window 77 Rubber 78 Sun visor 79a Left and right horizontal frame 79b Front and rear frame 80 Main clutch 81 Forward / reverse switching device 81F, 81R Hydraulic clutch 82 Main transmission 83 Sub transmission 84 Drive shaft 85 Rear wheel Differential device 86 Front wheel differential device 87 Rear axle 88L, 88R Brake device 89L, 89R Brake arm 90L, 90R Brake control valve 91L, 91R Brake piston 93 Forward / reverse switching lever 94 Forward / reverse switch 100 controller L1, L2 oil passage

Claims (2)

The work device (10, 9) can be freely mounted on the front and rear of the machine body (2) having the front and rear wheels (6a, 6b), and a three-point link is used instead of the work device (9) on the rear of the machine body (2). The working machine (35) can be mounted via the mechanism (36, 37) and the lifting lift arm (38), and the operator can change the direction forward and backward in the cockpit or two seats forward and backward In the work vehicle provided with (8),
Hydraulic cylinder (41) for raising and lowering the lifting lift arm (38), control valves (61, 62) for controlling the hydraulic pressure of the hydraulic cylinder (41), and actuators (61a, 61) for operating the control valves (61, 62) 62a) and when the seat (8) is in the rearward posture, it is permitted to operate the actuator (62a) in the direction of lowering the lifting lift arm (38), but the lifting lift arm (38) A work vehicle including a control device (100) that does not allow the actuator (61a) to be actuated in the upward direction.   Detecting means (70) for detecting the lifting position of the lifting lift arm (38) is provided, and the lifting arm (38) is raised in a direction higher than the lifting position set by the lifting lift arm (38). The work vehicle according to claim 1, further comprising a control device (100) for operating the actuator (62a) in a direction to lower the lifting lift arm (38) when it is detected that the lift has been moved.

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