JPH08242613A - Operation part structure in hydraulic traveling farm working machine - Google Patents

Abstract

PURPOSE: To provide the subject structure designed to prevent misoperations and improve the operability of the operation part. CONSTITUTION: In a hydraulic traveling farm working machine designed to prevent misoperations and mounted respectively with traveling left and right hydraulic motors on a pair of left and right crawler-type traveling sections and connect a pair of variable flow control pumps via a closed circuit fluid channel to the respective hydraulic motors, and interlockingly connect an operational section to both the variable flow control pumps to enable the operation part to conduct steering/variable-speed operations, the operation part has such a structure that the machine body frame is mounted with a steering box to conduct variable-speed actuation of a pair of pump variable-speed mechanisms placed between the pair of variable flow control pumps through interlocking with both a steering operation mechanism and a variable-speed operation mechanism and a circular handle constituting a part of the steering operation mechanism is disposed above the steering box.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operating section structure of a hydraulic traveling agricultural working machine provided with a crawler type traveling section.

[0002]

2. Description of the Related Art Conventionally, as a hydraulic traveling agricultural working machine provided with left and right independent crawler type traveling parts, there is a combine, for example, in which a left and right traveling hydraulic motor is provided to each of a pair of left and right crawler type traveling parts. A variable flow control pump is connected to each traveling hydraulic motor via a closed circuit oil passage, and each traveling hydraulic motor can be driven by each variable flow control pump. The trunnion lever of each variable flow control pump is provided. In addition, two rod-shaped operation levers provided independently on the left and right are interlocked and linked, and the steering operation can be performed by rotating each operation lever in the front-rear direction.

Moreover, the two operation levers are formed long in the vertical axis direction in order to reduce the operation load.

[0004]

However, in the above combine, since the operating lever is formed long,
When the natural vibration of the variable flow control pump or the vibration of the machine during traveling propagates to the operating lever, the amplitude of the gripping part formed on the upper end of the operating lever increases, and the gripping part grips the gripping part. There is a possibility that an operator who performs the operation may make an erroneous operation, and there is a problem that operability is poor.

[0005]

Therefore, in the present invention, the left and right traveling hydraulic motors are respectively provided in the pair of left and right crawler type traveling portions, and a pair of variable flow rate control pumps are provided in each of the traveling hydraulic motors. In the hydraulic traveling agricultural work machine, which is connected via a road, and the operating parts are interlockingly connected to both variable flow rate control pumps, and the operating parts can be steered / shifted, the operating parts are attached to the machine frame. Attaching a steering box for accelerating and decelerating a pair of pump accelerating / decelerating mechanisms provided between the pair of variable flow rate control pumps by interlocking with a steering operating mechanism and a speed change operating mechanism, and a position above the steering box. A circular handle forming a part of the steering operation mechanism is arranged in the operation handle structure of the hydraulic traveling agricultural working machine.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 is an agricultural tractor as a hydraulic traveling agricultural working machine equipped with an operating portion M according to the present invention. The agricultural tractor A has a rotary tiller B and the like at the rear. Lifting mechanism C of three-point link type
It is connected so that it can be moved up and down so that various work machines can be used.

As shown in FIGS. 1 and 2, the agricultural tractor A has a body frame 3 which is horizontally mounted between the traveling frames 2 and 2 of a pair of left and right crawler type traveling portions 1 and 1 to form the same body frame. 3 is provided with a prime mover portion 4 on the front portion thereof, while an integral support machine frame 5 is mounted on the rear portion thereof via front and rear vibration isolator (not shown), and the cabin 8 and the fuel are mounted on the same body support machine frame 5. A tank 9 and a hydraulic oil tank 10 are provided.

As shown in FIG. 1 and FIG. 2, the prime mover section 4 is a condenser 13, an oil cooler 14, a radiator 15, an engine 16, a muffler 17, and a main cleaner 18 in order from the front end of the machine frame 3 toward the rear. , And a pre-cleaner 19 are arranged, and an air cut plate 20 is erected from the machine body frame 3 between the engine 16 and the main cleaner 18, and the prime mover part 4 and the bonnet 21 are the same. The front end edge of the bonnet (21) is covered with a front grille (22) that is openably and closably attached to the front through a pivot bracket (23).

Moreover, as shown in FIGS. 3 and 4, the engine 16 includes a mission section 25, a pair of variable flow rate control pumps PL, PR, a work machine lifting hydraulic pump P1, and a charge pump.
P2 and P2 are integrally and interlockingly connected in the front-rear direction, and are integrally supported on the machine body frame 3 via the vibration isolator 120, 120, 120, 120.

That is, as shown in FIGS. 3 and 4, the machine body frame 3 includes a pair of left and right machine body frame forming bodies 3a, 3a extending in the front-rear direction, and a lower surface of a middle portion of both machine body frame forming bodies 3a, 3a. It is formed from the horizontal frame forming body 3b that is horizontally mounted via the mounting brackets 3c and 3c, and the stays 121 and 121 are attached to the front parts of the body frame forming bodies 3a and 3a, respectively. While supporting the side front part via the vibration isolator 120,120, the left rear part and the right rear part of the mission part 25 are respectively attached to the left mounting bracket 3c and the stay 122 mounted on the right rear surface of the lateral frame forming body 3b. It is supported through the tools 120, 120.

As shown in FIGS. 3 and 4, each vibration isolator 120 has a pair of upper and lower cover bodies 123 and 124, and a pair of upper and lower ring-shaped anti-vibration rubbers 125 and 126 arranged between the cover bodies 123 and 124. And a mounting bolt 127 and a mounting nut 128 which penetrate through the stays 121 and 122 or the mounting bracket 3c so as to pass through them in a vertically longitudinal direction.

In addition, between the pair of upper and lower anti-vibration rubbers 125, 126, the anti-vibration tool mounting bodies 16a, 16a projecting from the left and right side walls of the engine 16 in the horizontal direction respectively, or the left side wall rear part and the rear wall of the mission part 25 With the vibration isolator mounts 25a and 25b protruding horizontally on the right side of each
a, 16a, 25a, 25b and vibration isolator 120, 120, 120, 120
It is attached to 1,121,122 or mounting bracket 3c with mounting bolt 127.

In this way, the vibrations generated by the engine 16 and the transmission unit 25 and the pumps PL, PR, P1, P2, which are integrally and interlocked, are isolated by the four vibration isolator 120, 120, 120, 120. Vibration is not transmitted to the body frame 3.

As shown in FIGS. 1 and 2, a cabin 8 is mounted on the integrated support frame 5, and an operating section M is provided on a floor F in the cabin 8 and the operating section is provided. By using M, the rotation ratio of the left and right traveling hydraulic motors ML and MR, which will be described later, is changed, and the left and right traveling variable flow control pumps PL and PR are controlled to synchronize and accelerate the left and right traveling hydraulic motors ML and MR. In addition, the operating unit Q is configured by enabling the steering and gear shifting operation of the machine body and disposing the seat 26 at a position immediately behind the operation unit M via the seat support 27.

Next, the operating portion M, which is the subject matter of the present invention, will be described with reference to FIGS.

That is, as shown in FIGS. 5 to 8, the operating portion M includes a steering box 40 extending in the left-right width direction between the pair of left and right machine body frame forming bodies 3a, 3a.
The steering box 40 allows the pair of pump accelerating and decelerating mechanisms N, N to be accelerated and decelerated by interlocking with a steering operating mechanism 33 and a gear shift operating mechanism 37 which will be described later.

Then, on the steering box 40,
As shown in FIGS. 5 to 7, the handle column 28 is erected,
A circular handle 29 that forms a part of the steering operation mechanism 33 is attached to the upper end of the handle column 28, and a forward / backward speed adjustment lever that forms a part of the speed change operation mechanism 37 near the left side of the handle 29. While the 30 is mounted, an accelerator lever 81 is attached at a position near the right side, a PTO on / off lever 82 is attached at a position directly below the accelerator lever 81, and a brake pedal 31 is provided at an upper left position of the steering box 40. Reference numeral 85 is a brake pedal lock mechanism, 85a is a lock hook, and 85b is a lock hook rotation operation lever.

The steering operation mechanism 33 described above is shown in FIGS.
As shown in Fig. 5, the lower end of the lower half transmission shaft 33a extending in the vertical direction is connected to the pinion shaft 46a protruding upward from the front center of the ceiling wall of the steering box 40 by the interlocking coupling body 33.
An upper half transmission shaft that extends upward and rearward at the upper end of the lower half transmission shaft 33a that is interlockingly connected vertically via b
The lower end of 33c is interlockingly connected via a universal joint 33d, and the center part of the circular handle 29 is attached to the upper end of the upper half transmission shaft 33c, and the upper half transmission shaft 33c is the transmission shaft. Insert into the insertion tube 33e to insert the same transmission shaft.
33e is supported by a support frame 32 mounted in the handle column 28.

In this way, by rotating the handle 29, the upper half transmission shaft 33c → universal joint 33d → lower half transmission shaft 33a → interlocking coupling body 33b → pinion shaft 46a of the steering box 40 is rotated. The dynamic operating force is transmitted, and the steering box 40 → a pair of pump acceleration / deceleration mechanisms N, N → a pair of variable flow rate control pumps PL, PR → a left / right traveling hydraulic motor ML, MR → a crawler type left / right traveling section 1, 1 The steering operation of is made possible.

At this time, the pinion shaft 46a of the steering box 40 attached to the machine body frame 3 and the steering operation mechanism 33.
The lower half of the lower half of the transmission shaft 33a is interlocked with the interlocking link 33b to absorb the vibration of the machine frame 3 generated during traveling by the interlocking link 33b, and the vibration to the steering wheel 29. To prevent the spread of.

Therefore, it is possible to prevent an erroneous operation of the operator who carries out the steering operation by gripping the handle 29 and improve the operability of the machine body.

Moreover, by operating the circular handle 29, a pair of variable flow rate control pumps PL, PR are provided via the steering box 40 and the pair of pump acceleration / deceleration mechanisms N, N.
Since it is possible to accelerate and decelerate, the operating load can be reduced, and smooth and reliable steering operation can be performed even in muddy wetlands, which also improves the operability of the aircraft. Can be made.

As shown in FIGS. 5 and 7, the speed change operation mechanism 37 includes a shaft support pipe extending in the lateral width direction of the support frame 32.
The lower end of the forward / backward speed adjusting lever 30 that extends 65 horizontally and inserts a lever support shaft 66 that extends in the left-right width direction into the coaxial support pipe 65 and extends upward to the left end of the lever support shaft 66. Is connected via a connecting body 34, an operating arm 67 is projected forward in the middle of the lever support shaft 66, and the upper end of the connecting rod 68 is connected to the front end of the operating arm 67. A boss portion 69 having an axis lined in the left-right width direction is attached to the left side portion of the front wall of the steering box 40 via a mounting bracket 70, and a support shaft 71 extending in the left-right width direction is inserted into the boss portion 69, and the support shaft is attached. 71
The base end of the arc-shaped arm 72 is attached to the right end of the arm 72, the lower end of the connecting rod 68 is connected to the tip of the arc-shaped arm 72, and the base end of the arm 73 is bossed to the left end of the support shaft 71. A connecting portion 75, one end of a connecting rod 75 is connected to the tip of the arm 73, and the other end of the connecting rod 75 is a boss portion provided on the left end portion of the speed change shaft 41 of the steering box 40 described later. It is connected to an arm 77 protruding from 76.

In this way, the forward / backward speed adjusting lever 30
When the lever is rotated forward on the forward operation side or backward on the reverse operation side, the turning force of the lever 30 causes the lever support shaft to rotate.
66-> operating arm 67-> connecting rod 68-> arcuate arm 72-> spindle 71-> boss 74-> arm 73-> connecting rod 75-> arm 77->
The transmission shaft 41 is transmitted to the transmission shaft 41 to rotate the transmission shaft 41.

Moreover, the gear shift operating mechanism 37 is provided with lever operating position holding means 78 as shown in FIGS. 5 and 7, and the lever operating position holding means 78 is provided on the left end surface of the shaft support pipe 65. A ring-shaped friction plate receiver 79 is attached, and a ring-shaped friction plate 80 is interposed between the friction plate receiver 79 and the operating arm 67, while the lever support shaft is inserted into the shaft support pipe 65.
A spring support protrusion 66a is provided at the right end of the shaft 66 so as to protrude outward from the right end of the shaft support pipe 65, and a spring receiver 66 is attached to the outer end of the spring support protrusion 66a.
The spring 84 is provided between the shaft support pipe 65 and the spring support 66c provided on the right end surface of the shaft support pipe 65.
It is wound around and intervened.

In this way, the lever operation position holding means
In 78, the friction plate 80 is clamped by the friction plate receiver 79 and the operating arm 67 by the pressing force of the spring 84, and the forward / backward speed adjusting lever 30 is rotated in the forward / backward direction by the friction plate 80. When you release your hand, the friction plate 80
It allows the 30 to be held in its operating position.

Further, as shown in FIGS. 5 and 7, the forward / backward speed adjusting lever 30 is provided with a lever restricting body 110 capable of adjusting the range between the lever neutral restriction and the lever speed changing operation restriction and the speed changing operation mechanism 37. Are connected by another route.

That is, as shown in FIGS. 5 and 7, the lever restricting body 110 is provided with a boss portion 111 having an axis lined in the left-right width direction on the supporting machine frame 32, and a swinging support shaft in the boss portion 111. 11
2 is swingably supported, and the middle part of the slide guide cylinder 113 extending vertically is integrally attached to the left end of the rocking support shaft 112 so that the middle part of the slide guide cylinder 113 swings together with the middle part. Neutral regulation ball accommodating portions 114 and 115 are formed in the support shaft 112, respectively, and the neutral regulation balls are biased in the accommodating portions 114 and 115 by springs 116 and 116 in opposite directions.
While housing 117, 117, a slide rod 118 having an upper end connected to the operating arm 67 is vertically slidably inserted into the slide guide cylinder 113, and a neutral regulation ball engaging groove 118a is formed on the peripheral surface of the slide rod 118 in the middle thereof. The forward speed limiter 119 and the reverse speed limiter at the upper and lower ends, respectively.
120 and 120 are screwed in the axial direction of the slide rod 118 so that the forward and backward positions can be adjusted.

In this way, the forward / backward speed adjusting lever 30
Is in the neutral position, the neutral restriction balls 117, 117 are engaged in the neutral restriction ball engaging groove 118a, and when the lever 30 is operated to switch to the forward side or the reverse side, the spring 11
Since it is necessary to disengage the neutral restriction balls 117, 117 from the neutral restriction ball engaging groove 118a by sliding the slide rod 118 against the pressing biasing force of the 6,116, the operator moves the lever 30 to the neutral position. By doing so, it is possible to easily experience the fact that the neutral position is switched to either of the forward and backward movements to prevent erroneous operation.

Then, when the forward / backward speed adjusting lever 30 is rotated forward to the forward operation side, the slide guide cylinder 11
The forward speed regulator 119 comes into contact with the upper end surface of 3 and
When the lever 30 is rotated rearward, which is the backward operation side, while the forward operation of the lever 30 is restricted, the reverse speed regulator 120 comes into contact with the lower end surface of the slide guide cylinder 113, and the backward operation of the lever 30 is prevented. I am trying to regulate it.

At this time, the forward / backward speed regulating members 119, 120 are respectively adjusted in the forward / backward positions in the axial direction of the slide rod 118 so that the forward / backward traveling speed regulation range can be appropriately adjusted according to the operator's preference. There is.

In addition, the lever restricting body 110 has a path different from that of the speed change operation mechanism 37 in which the connecting rod interposed between the tips of the actuating arm 67 and the arcuate arm 72 swinging in the vertical direction makes an elliptic motion, that is, Since the slide guide cylinder 113 swings in the front-rear direction about the swing support shaft 112, it is interposed between the actuating arm 67 that swings in the vertical direction and the fixed swing support shaft 112. Nevertheless, the slide rod 118 slides smoothly in the slide guide cylinder 113, so that the neutral regulation of the forward / backward speed adjusting lever 30 and the forward / backward regulation can be surely performed.

Further, the forward / backward speed adjusting lever 30 for adjusting the forward / backward speed of the left and right traveling parts 1, 1 is provided with a handle.
By arranging it near the left side of 29, and by arranging the tip gripping part 30a of the forward / backward speed adjusting lever 30 close to the gripping part of the handle 29, the operator can handle with the right hand.
The operator can easily operate the forward / backward speed adjusting lever 30 with his / her left hand while gripping 29 and performing a steering operation. Therefore, a safe and reliable steering operation can be performed even in a work that requires frequent forward / reverse switching operations, and the operability of the machine body can be improved.

The brake pedal 31 is shown in FIGS. 6 and 7.
As shown in, the pedal arm 31c is attached to the pedal support shaft 31a protruding from the support frame 32 in the left-right width direction via the boss portion 31b, and the operating arm 31d is attached to the front lower portion of the boss portion 31b. Projecting toward, and connecting rod to the actuating arm 31d.
While connecting the upper end of 31e, a pilot oil passage switching valve 94 is attached to the front wall of the steering box 40 via a stay 40b, and the connecting rod is connected to the spool 94a of the valve 94.
The lower end of 31e is connected. 31f is a pedal restoring spring In this way, by depressing the brake pedal 31, the boss portion 31b → the operating arm 31d → the connecting rod 31e → the spool 94a can be operated to switch the pilot oil passage. I am trying.

Here, in the embodiment of the present invention, as shown in FIGS. 5 and 16, a two-pump / two-motor type HST is used as a continuously variable transmission, and the left and right traveling sections 1 and 1 travel separately. It is drivable, and the handle 29 is of a rotary type, and by changing the number of rotations and the direction of rotation of each crawler of the left and right traveling units 1 and 1 in accordance with the amount of rotation, the aircraft can be turned, and at the same time. , By rotating the forward / backward speed adjustment lever 30, the left and right hydraulic motors ML, M
The rotation speed and rotation direction of R can be changed.

The forward / backward speed adjusting lever 30 and the handle 29 are constructed so that they can be operated separately, and are interlocked with a pair of left and right pump acceleration / deceleration mechanisms N, N in the steering box 40 to accelerate and decelerate both pumps. As shown in FIG. 16, the mechanisms N and N are provided with HST variable flow control pumps PL and PR.
The left and right swash plates 101, 102 of each hydraulic motor ML, MR are controlled by connecting the left and right traveling hydraulic motors ML, MR to the pumps PL, PR respectively. The side traveling parts 1 and 1 can be respectively moved forward, backward, and stopped.

That is, since the internal structure of the steering box 40 is substantially symmetrical as shown in FIGS. 9 to 11, one side will be described. At the front position of the transmission shaft 41 having a triangular cross section, A slide shaft 44 is horizontally installed in parallel with the transmission shaft 41. A pair of left and right slide bodies 43, 43 are fitted onto the transmission shaft 41 so as to be slidable in the axial direction, and a slide acting body 45 interlockingly connected to the handle 29 is arranged between the slide bodies 43, 43. , A pair of pump acceleration / deceleration mechanisms N, N are interlockingly connected to the slide bodies 43, 43, respectively. The arm 55, the first connecting rod 56, the first arm 86, the intermediate shaft 87, the second arm 88, and the second connecting rod 89 are provided.

The slide acting body 45 includes a base portion 45a attached to the slide shaft 44 so as to be slidable in the axial direction, and a main body 45b integrally attached to the base portion 45a and arranged immediately in front of the slide shaft 44. The main body 45b is shaped like a gate in a front view, and a rack 45c formed by extending in the left-right width direction is fixed to the upper surface of the main body 45b.

A pinion gear 46 is meshed with the rack 45c. The pinion gear 46 is fixed to the pinion shaft 46a, and the pinion shaft 46a is interlockingly connected to the lower end of the lower half transmission shaft 33a of the handle 29 arranged above through the interlocking coupling body 33b. Therefore, when the handle 29 is rotated, the pinion gear 46 rotates, the rack 45c interlocks and slides in the left-right width direction, and the slide action body 45 slides accordingly, and the left and right sides of the slide action body 45. One of the slide bodies 43, 43 engaged with the ends is pulled.

An arm support portion 47a of a guide support arm 47 is loosely fitted to the outside of the outer peripheral surface of the slide body 43, and a detent body 47b is provided from the rear outer peripheral surface portion of the arm support portion 47a toward the transmission shaft 41. The same rotation stop body 47b is loosely fitted to the speed change shaft 41 via the interlocking slide body 48 so as to be slidable in the left and right axial directions. On the other hand, a boss portion 47d is formed on the rear portion of the arm support portion 47a, and a pivot pin whose axis is vertically oriented to the boss portion 47d.
The upper end of 47e is pivotally supported, and the center of the upper wall of the guide body 50 is rotatably attached to the lower end of the pivotally supported pin 47e. The guide body 50 extends in the left-right direction and has a U-shaped cross-section when the lower surface is opened.

Further, a swing arm 48a extends downward from the lower portion of the outer peripheral surface of the interlocking slide body 48, and a rear end of a swing link 48c, which is adjustable in expansion and contraction, is connected to a lower end of the swing arm 48a by a connecting pin 48b. The front end of the swing link 48c is pivotally supported on the one end of the upper wall of the guide body 50 via a connecting pin 48d. 48e is a neutral return spring interposed between the pair of left and right interlocking slide bodies 48, 48.

A rotatable rotor 51 is inserted into the recess of the guide body 50 and is slidably fitted in the left-right direction. The shaft center of the rotor 51 is in the left-right width direction. Is attached to one end of the rotor support arm 52 extending to the other side, and the other end of the rotor support arm 52 is attached to the steering box 40.
A boss portion 53 fixed to the bottom wall of the steering box 40 is pivotally supported by an arm support shaft 54 having an axis oriented in the vertical direction so that the arm support shaft 54 can swing left and right.
The end of the swash plate actuating arm 55 extending in the left-right width direction is fixed to the end of 54 by a fixing bolt 55a, and the other end is connected to one end of a first connecting rod 56 via a connecting pin 56a. The tip end of the first arm 86 is connected to the other end of the one connecting rod 56, and the base end of the first arm 86 is attached to the upper end of the intermediate shaft 87 attached to the HST via the stay 130 with its axis extending vertically. The base end of the second arm 88 is attached to the lower end of the intermediate shaft 87, and the second connecting rod is attached to the tip of the second arm 88.
One end of 89 is connected, and the other end of the second connecting rod 89 is HS.
It is connected to the T spool control lever 100.

In such a structure, the sliding action body 45 is slid by the rotation of the handle 29, and one of the slide bodies 43, 43 is pulled along the slide shaft 44 and the speed change shaft 41, and the slide body 43 and The guide body 50 provided integrally is slid.

When the speed change shaft 41 is rotated by the forward / reverse speed adjusting lever 30, the guide body 50 is moved forward and backward around the pivot pin 47e via the swing link 48c connected to the slide body 43. The arm 55 for rocking is swung around the arm support shaft 54.

Next, the states of the guide body 50 when the handle 29 and the forward / backward speed adjusting lever 30 are operated are shown in FIGS.
Will be described with reference to.

That is, when the forward / reverse speed adjusting lever 30 is set to the neutral state and the rotary handle 29 is also set to the neutral state at the same time, the left and right guide bodies 50, 50, the rotor support arm 5
2, 52 and the swash plate actuating arms 55, 55 maintain a horizontal posture, as shown in FIG.

When the forward / reverse speed adjusting lever 30 is operated to shift to the forward shift position from this state, the shift shaft 41 is rotated, and the left and right slide bodies 43, 43, swing arms 48a, 48a, swing links 48c, 48c is interlocked, and the left and right guide bodies 50, 50 are pivotally supported pins.
Rotate around 47e, 47e, and then rotate the left and right rotors 51, 5
1 through rotor support arm 52,52, arm support shaft 54,54
, The swash plate actuating arms 55, 55 are, as shown in FIG.
Be inclined. In this case, the left and right traveling hydraulic motor M
The left and right swash plates 101 and 102 that control L and MR have the same inclination angle, the left and right traveling units 1 and 1 travel forward at the same speed, and the aircraft travels straight.

Next, when the handle 29 is turned counterclockwise by turning the handle 29 from the straight-ahead state, the pinion shaft 46a is rotated and the rack 45c meshing with the pinion gear 46 is moved to the right to move the rack 45a. At the same time, the slide acting body 45 pulls and slides the left slide body 43 to the right side.

Then, the guide body 50 on the left side is the slide body 43.
Together with this, the guide body 50 slides rightward while the guide body 50 slides to the right while maintaining the tilted posture. Then, as shown in FIG. 14, the rotor 51 fitted to the right guide body 50 is pushed downward to be fitted to the substantially central position of the left guide body 50. The left rotor support arm 52 and the swash plate actuating arm 55 are rotated to approach a horizontal posture, and the left swash plate 98 for controlling the left traveling hydraulic motor ML is brought close to a neutral state. In this case, the left traveling unit 1 decelerates or stops from the straight traveling state, and the right traveling unit 1 continues forward traveling, so that the aircraft slowly turns to the left.

Next, in the above left turning state, the handle
When 29 is further rotated leftward, the left guide body 50 slides further to the right in the tilted posture, and the left rotor 51 moves to the left side portion of the guide body 50 as shown in FIG. In the mated state, the rotor support arm 52
The swash plate operating arm 55 has a left high tilted right low tilted posture,
The left swash plate 98 is tilted to the reverse control side. In this case, the traveling unit 1 on the left side travels in the reverse direction, while the traveling unit 1 on the right side moves in the forward direction, so that the body makes a spin turn.

Next, the hydraulic circuit K will be described with reference to FIG. That is, the hydraulic circuit K connects the HST hydraulic circuit 90 to the hydraulic tank T, connects the left side traveling unit driving hydraulic circuit 91 and the right side traveling unit driving hydraulic circuit 92 to the HST hydraulic circuit 90, respectively. The working machine lifting hydraulic pump P1 linked to the pair of variable flow control pumps PL and PR of the circuit 90 is connected to the working machine lifting hydraulic circuit 93, while the charge pump linked to the variable flow control pumps PL and PR is linked. Connect the brake devices 95 and 96 provided in the left and right side drive hydraulic circuits 91 and 92 to P2 via the pilot oil passage 135,
A pilot oil passage switching valve 94 is attached in the middle of the pilot oil passage 135. 97 is a bypass operation switching valve, 136
Is a swash plate angle control means, 148 is a closed circuit oil passage interposed between the variable flow rate control pump PL and the left traveling hydraulic motor ML, 149
Is a closed circuit oil passage interposed between the variable flow rate control pump PR and the right traveling hydraulic motor MR.

The pilot oil passage switching valve 94 is interlocked with the brake pedal 31, and the pilot oil passage switching valve 94 is switched in association with the depression operation of the brake pedal 31, and the brake device 95, 96 is configured to brake.

That is, the brake devices 95, 96 are provided with piston rods 95c, 96c urged in the extension direction by springs 95b, 96b in cylinders 95a, 96a, respectively, and press-contact members are attached to the tips of the piston rods 95c, 96c. 95d, 96d are attached, and each pressure contact body 95d, 96d is connected to the drive wheel 1a, 1a of each traveling section 1, 1.
By supplying pilot oil into each cylinder 95a, 96a, the piston rods 95c, 96c are shortened against the bias of the springs 95b, 96b, and the pressure contact body is pressed.
By separating 95d and 96d from the drive wheels 1a and 1a so that they can be brought into a non-brake operating state, by discharging pilot oil from each cylinder 95a and 96a,
The urging force of the springs 95b, 96b causes the piston rod 95c,
96c is extended to drive the pressure contact bodies 95d and 96d to drive wheels 1a and 1a.
It is possible to bring the brakes into operation by putting them in pressure contact with each other.

In this way, by depressing the brake pedal 31, the driving of the left and right traveling parts 1, 1 can be stopped at the same time by the left and right braking devices 95, 96. Brake depressing operation can be performed with the same feeling as depressing operation, and good safety can be ensured.

In the present embodiment, the steering box 40 is horizontally mounted between the body frame forming bodies 3a, 3a.
It can also be integrally provided on the upper part of the HST.

[0057]

According to the present invention, the following effects can be obtained.

That is, in the present invention, since the pair of pump acceleration / deceleration mechanisms are provided between the steering box and the pair of variable flow rate control pumps, the natural vibration generated in the variable flow rate control pump is The acceleration / deceleration mechanism absorbs the vibrations, damps the vibrations to the steering box, and prevents the vibrations from propagating to the steering wheel arranged above the steering box. Therefore, it is possible to prevent an erroneous operation of an operator who holds the handle and performs a steering operation, and improve the operability of the machine body.

Further, the vibrations of the machine body during traveling are absorbed by the steering box and a part of the steering operation mechanism, and the handle attached to the upper end of the steering operation mechanism has a damped vibration which does not affect the operability. Since only this is propagated, it is possible to prevent an erroneous operation by an operator who holds the handle and carries out a steering operation, and to improve the operability of the machine body.

Moreover, since the variable flow rate control pump can be operated to be accelerated and decelerated through the steering box and the pump acceleration and deceleration mechanism by operating the steering wheel, the operation load can be reduced. It is possible to improve the sex.

[Brief description of drawings]

FIG. 1 is a side view of an agricultural tractor including an operating portion structure according to the present invention.

FIG. 2 is a plan view of the agricultural tractor.

FIG. 3 is a side view showing an anti-vibration support structure of the engine.

FIG. 4 is a plan view showing an anti-vibration support structure of the engine.

FIG. 5 is a side view of the operation unit.

FIG. 6 is a side view of the operation unit.

FIG. 7 is a front view of the operation unit.

FIG. 8 is a plan view of the operation unit.

FIG. 9 is a cross-sectional plan view showing the internal structure of the steering box.

FIG. 10 is a sectional front view showing the internal structure of the steering box.

FIG. 11 is a sectional side view showing the internal structure of the steering box.

FIG. 12 is a partial front view of the steering box in a neutral state.

FIG. 13 is a partial front view of the steering box in a straight traveling state.

FIG. 14 is a partial front view of the steering box in a right turning state.

FIG. 15 is a partial front view of the steering box during a pivot turn.

FIG. 16 is a hydraulic circuit diagram.

[Explanation of symbols]

 A Agricultural tractor 1 Travel part 2 Travel frame 3 Airframe frame 4 Motor part

Claims (1)

[Claims] 1. A pair of left and right crawler type traveling portions are respectively provided with left and right traveling hydraulic motors, and a pair of variable flow rate control pumps are connected to the respective traveling hydraulic motors via a closed circuit oil passage to provide both variable flow rates. In a hydraulic traveling agricultural work machine in which an operating section is interlockedly connected to a control pump, and the operating section can be operated to steer and shift, the operating section includes a steering operation mechanism and a shift operation mechanism on a machine body frame. A steering box for accelerating and decelerating a pair of pump accelerating / decelerating mechanisms provided between the pair of variable flow rate control pumps is attached to the steering box, and a part of the steering operation mechanism is formed above the steering box. The structure of the operating part of the hydraulic traveling agricultural work machine, which is characterized by arranging circular handles.