JP2003294136A - Traveling vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To operate a continuously variable transmission for turning with minor operation load. <P>SOLUTION: On a transmission part, a continuously variable transmission for turning and a transmission for straight advance are interlockedly coupled to each other, and a steering wheel is interlockedly coupled to them via operation mechanism for turning. Meanwhile, a forward/backward switch lever is interlockedly coupled to the transmission for straight advance via operation mechanism for straight advance, and a booster for turning operation is placed on the halfway of the operation mechanism for turning. Further, a booster for straight advance is placed on the halfway of the operation mechanism for straight advance. As a result, operation load of the continuously variable transmission for turning is reduced by the booster for turning placed on the halfway of the operation mechanism for turning upon operation of the continuously variable transmission for turning via the operation mechanism for turning by the steering wheel. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a traveling vehicle.

[0002]

2. Description of the Related Art Conventionally, as one form of a traveling vehicle, power can be transmitted from a continuously variable transmission for turning connected to an engine to a power transmission system for turning provided in a front mission section, while it is interlocked with an engine. It is possible to transmit power to the straight drive power transmission system provided in the front mission section via the rear mission section by the connected straight transmission and to transmit the power of these turning / straight drive power transmission system in the front mission section. There is a system in which the planetary gear mechanism provided in the above is combined to transmit the resultant force to the left and right drive wheels, respectively.

A steering wheel is interlockingly connected to the continuously variable transmission for turning through a turning operation mechanism, and a forward / reverse switching lever is interlockedly connected to the straight ahead transmission through a straightening operation mechanism.

In this way, the steering wheel operates the continuously variable transmission for turning through the operating mechanism for turning, and the forward / reverse switching lever operates the linear transmission for moving through the operating mechanism for straight traveling. The required steering operation is performed.

[0005]

However, in the above-described traveling vehicle, when each transmission is operated by the steering wheel or the forward / reverse switching lever, the operation load is received from each transmission or the load on each transmission is applied. As a result, a reverse load (so-called kickback) acts on each operation mechanism, which makes it difficult for the operator to perform a light operation, which causes fatigue.

[0006]

Therefore, in the present invention, a continuously variable transmission for turning and a linearly variable transmission are interlocked in a transmission section, and the continuously variable transmission for rotation is provided with a turning operation mechanism. While the steering wheel is interlockingly connected, the forward / reverse switching lever is interlockingly connected to the straight-ahead transmission via the straight-ahead operation mechanism, and a boosting device for a turning operation is provided in the middle of the turning operation mechanism, while a straight-ahead drive is provided. The present invention provides a traveling vehicle characterized in that a booster device for straight-ahead operation is provided in the middle of the operation mechanism for the vehicle.

The present invention is also characterized by the following configurations.

(1) The turning operation booster, the interlocking operation tool of the turning operation booster, and the rectilinear operation booster and the interlocking operation tool of the rectilinear operation booster respectively extend in the front-back direction. The boosters are arranged along the vicinity of the left and right vehicle body frame forming pieces, and each booster is hydraulically actuated to be branched from the charge oil passage to the transmission. The hydraulic oil was supplied to each booster via the oil supply passage.

(2) A continuously variable transmission for turning and a transmission for straight traveling are interlocked in a transmission section, and a steering wheel is interlockingly connected to the continuously variable transmission for turning through a steering operation mechanism. The forward-reverse switching lever is interlocked with the straight-travel transmission through the straight-travel operation mechanism, and a swivel booster is installed in the middle of the swivel operation mechanism, and the swivel booster is used for swivel. While arranging in parallel with the continuously variable transmission, a booster for rectilinear operation is provided in the middle of the rectilinear operation mechanism, and the booster for rectilinear operation is arranged in parallel with the rectilinear transmission. The booster has a spool that is linked to the upstream side of each operating mechanism, a piston that slides due to the pressure difference in the oil supply passage that occurs as the spool slides, and a base end that links each piston. While connecting, under each operating mechanism It is provided with an actuation arm which is operatively connected to the distal end portion on the side.

(3) The piston is slidably fitted on the outer peripheral surface of the middle portion of the spool, and is neutralized on both sides of the piston so as to maintain the neutral state when there is no pressure difference in the oil supply passage. The elastic means for maintaining the state is provided.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

That is, in the traveling vehicle according to the present invention, a continuously variable transmission for turning and a transmission for straight traveling are interlocked in a transmission section, and a steering wheel is provided to the continuously variable transmission for turning through a turning operation mechanism. On the other hand, the forward / reverse switching lever is interlockingly connected to the above-mentioned straight-ahead transmission via the straight-ahead operation mechanism, and a turning operation booster is provided in the middle of the above-mentioned turning operation mechanism, while a straight-ahead operation is performed. A booster for straight-ahead operation is provided in the middle of the mechanism.

Further, the turning operation booster, the interlocking operation tool of the turning operation booster, and the rectilinear operation booster and the interlocking operation tool of the rectilinear operation booster are respectively extended in the front-rear direction. Of the vehicle body frame forming pieces arranged in the vicinity of the left and right vehicle body frame forming parts, each booster is hydraulically operated, and the booster supply is formed by branching from the charge oil passage to the transmission. The hydraulic oil is supplied to each booster through an oil passage.

Further, a continuously variable transmission for turning and a transmission for straight traveling are interlocked in a transmission section, and a steering wheel is interlockingly connected to the continuously variable transmission for turning through an operation mechanism for turning. The forward-reverse switching lever is interlocked with the straight-travel transmission through the straight-travel operation mechanism, and a swivel booster is installed in the middle of the swivel operation mechanism, and the swivel booster is used for swivel. While arranging in parallel with the continuously variable transmission, a booster for rectilinear operation is provided in the middle of the rectilinear operation mechanism, and the booster for rectilinear operation is arranged in parallel with the rectilinear transmission. The booster has a spool that is linked to the upstream side of each operating mechanism, a piston that slides due to the pressure difference in the oil supply passage that occurs as the spool slides, and a base end that links each piston. In addition to connecting, each operation mechanism And it includes an actuation arm in conjunction connecting the distal portion to the downstream side.

Here, the piston is slidably fitted to the outer peripheral surface of the middle portion of the spool, and is neutralized on both sides of the piston so as to maintain the neutral state when there is no pressure difference in the oil supply passage. Elastic means for maintaining the state is provided.

[0016]

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

1 to 4 is a traveling vehicle according to the present invention, in which the vehicle body frame 2 is installed between a pair of left and right crawler type traveling portions 1 and 1, and A prime mover section 3 is provided at the front of the frame 2, a driving section 4 is provided at the rear of the frame 2, and a mission section 5 is provided below the driving section 4.

Each running unit 1 is, as shown in FIGS.
A running frame 10 that extends in the front-back direction and the running frame
Front and rear driven wheels 1 attached to the front and rear ends of 10 respectively
1, 12 and the drive wheels 13 disposed between the front and rear driven wheels 11 and 12 at an upper position, and the crawler belt 14 wound between these drive wheels 11, 12 and 13 to form a triangular shape in a side view. It has and. 15
Is a front driven wheel support shaft, 16 is a rear driven wheel support shaft, 17 is a drive wheel support shaft, 18 is a front driven wheel advancing / retreating position adjuster, 19 is an equalizer,
20 is a track disengagement prevention body, and θ is a take-off angle.

As shown in FIGS. 1 to 4, a pair of front and rear connecting frames 21 and 22 extending in the left and right direction are horizontally provided between the pair of left and right traveling frames 10 and 10.

As shown in FIGS. 1 to 4, the body frame 2 includes a pair of left and right body frame forming pieces extending in the front-rear direction.
23, 23, a mission section 5 installed between the rear parts of both body frame forming pieces 23, 23, and an axle case 24 formed by extending left and right outside from the left and right rear parts of the mission section 5. There is.

The midway portions of the pair of left and right body frame forming pieces 23, 23 are fixed on the front connecting frame 21, and the pair of left and right running frames 10, 10 are erected above the rear portions of the pair of left and right traveling frames 10, 10. An axle case 24 is installed between the support stands 25, 25.

As shown in FIG. 1, the prime mover section 3 has an engine E mounted between the front portions of a pair of left and right body frame forming pieces 23, 23, and a radiator 27 arranged in front of the engine E.
These are covered with a hood 28.

At the rear of the engine E, as shown in FIG. 2 and FIG.
The transmission unit 5 is linked to the flywheel unit 29 via a transmission shaft 30.

As shown in FIGS. 1 to 3, the driving section 4 is provided with a driving section support frame 31 on an intermediate portion of the vehicle body frame 2, and a steering column 32 is provided in front of the driving section support frame 31. Stand upright, and attach the wheel support 33 to the upper end of the steering column 32.
The steering wheel 34 is attached via the steering wheel 34, the driver seat 35 is arranged at the rear position of the steering wheel 34, the fuel tank 36 is arranged at the left side position of the driver seat 35, and the battery 37 is arranged at the right side position. ing.

Then, the steering column 32 and the driver's seat 35
A floor 38 is stretched on the driving part support frame 31 located between and, and the left and right support frames 39, 3 from the middle of the left and right sides of the floor 38.
9 is extended rearward and upward, and the base end of the forward / reverse switching lever (shift lever) 40 is attached to the right support frame 39 by a lever mounting body.
It is attached via 41. 190 is a canopy.

As shown in FIGS. 2 and 3, the mission section 5 includes a mission front lid portion 42, a mission body portion 43 integrally connected to the axle case 24, the mission front lid portion 42 and the mission body. A transmission intermediate portion 44 provided between the transmission portion 43 and the portion 43 is detachably connected to the transmission front portion 42, and the transmission front portion 42 for straight traveling is a hydrostatic continuously variable transmission as a transmission for straight traveling. HST6 and HST for turning, which is a hydrostatic continuously variable transmission as a continuously variable transmission for turning
7 and 7 are linked in parallel on the left and right.

Here, in this embodiment, the mission main body portion
Since the 43 and the axle case 24 are compactly and integrally molded, the mission body 43 and the axle case 24 can be easily and surely attached to the vehicle body frame 2.

As shown in FIG. 5, in the mission unit 5, a straight drive power transmission system 45, a turning power transmission system 46, a PTO power transmission system 47, and a pump drive power transmission system 48 are integrated. The engine E has a flywheel part.
The input shaft 49 provided on the transmission front cover 42 is interlocked via 29 and the transmission shaft 30, and the power input through the input shaft 49 is transmitted in the transmission intermediate portion 44 to the straight drive power transmission system 45. And the power transmission system 46 for turning, and at the same time, they are transmitted to the power transmission system 47 for PTO and the power transmission system 48 for pump drive in the front cover 42 of the mission. 45, 46, 47 and 48 are branched and transmitted in two sets.

That is, as shown in FIG. 5, the rectilinear power transmission system 45 includes an input shaft 49 provided on the mission front cover 42,
A planet that is interposed between a drive shaft 50 that is installed in the axle case 24 with the axis line oriented in the left-right direction, and is arranged at the left and right end portions of the drive shaft 50 on the left and right side portions within the axle case 24. The sun gears 52, 52 of the gear mechanism 51, 51 are interlockingly connected.

The input shaft 49 is connected to the mission front cover 42.
The first output gear 53 is installed in the transmission intermediate portion 44 at the rear end of the input shaft 49.
Attached, the first output gear in the middle section 44 of the same mission
A straight-travel input gear 55 is meshed with 53 via a straight-travel intermediate gear 54, and the straight-travel input gear 55 is directed to the right side of the transmission front cover 42 so that the axis of the straight-travel HST 6 is straight. It is attached to 56. Reference numeral 57 denotes a first intermediate shaft that is installed between the mission front cover portion 42 and the mission intermediate portion 44 with the axis line oriented in the front-rear direction.

Moreover, the straight-travel output shaft 58 projecting rearward from the straight-travel HST 6 in the mission front cover portion 42 has a straight-travel first output shaft 58 extending in the front-rear direction in the mission main body portion 43. The front end portion of the first transmission shaft 59 is interlocked and coupled, and the first straight transmission shaft 59 is connected to the first straight transmission shaft 59 through the straight transmission speed change shaft 60 to the second straight traveling shaft.
The transmission shaft 61 is interlockingly connected, and the drive shaft 50 is interlockingly connected to the rear end portion of the second rectilinear transmission shaft 61 via bevel gears 62 and 63.

Here, the straight-travel speed change shaft 60 and the straight-travel second transmission shaft 61 are installed in the transmission main body portion 43 with their axes oriented in the front-rear direction so as to be in parallel with the first straight-travel transmission shaft 59. The large-diameter gear 64 and the small-diameter gear 65 are attached to the first linear transmission shaft 59, while the small-diameter transmission gear 66 that meshes with the large-diameter gear 64 and the small-diameter gear 65 are attached to the straight-transmission transmission shaft 60. A large-diameter transmission gear 67 and a transmission output gear 68 that mesh with each other are attached, and the transmission output gear 68 is meshed with a rectilinear second input gear 69 attached to the rectilinear second transmission shaft 61. Reference numeral 113 is a shifter for shifting gears for straight running.

In this way, by operating the shifter 113 for shift operation for rectilinear movement, it is possible to shift gears in two stages of high speed and low speed.

Further, a parking brake 70 is interlockingly connected to the front end portion of the straight-moving transmission shaft 60, and the parking brake 70 is disposed in the transmission intermediate portion 44.

As shown in FIG. 5, the turning power transmission system 46 includes an input shaft 49 provided on the transmission front cover 42 and planetary gear mechanisms 51, 51 provided on the left and right side portions of the axle case 24. It is interposed between the ring gears 72 and 72.

The first output gear 53 attached to the input shaft 49 is connected to the turning intermediate gear 73 in the intermediate portion 44 of the transmission.
The turning input gear 74 is meshed with the turning input gear 74, and the turning input gear 74 is attached to the turning input shaft 75 of the turning HST 7 having its axis lined in the front-rear direction on the left side portion of the mission front cover 42. 76 is the mission front cover 42 with the axis lined in the front-rear direction.
It is a second intermediate shaft that is erected between the transmission and the intermediate portion 44 of the mission.

In addition, the turning output shaft 77 protruding rearward from the turning HST 7 in the mission front cover portion 42 extends in the front-rear direction across the mission front cover portion 42, the mission intermediate portion 44, and the mission body portion 43. The second transmission shaft for rotation, which is erected with the axis line in the front-rear direction in the mission main body 43, via the first transmission shaft 78 for rotation, which is installed with the axis line to
79 is interlockingly connected, and a pair of left and right third power transmission shafts 80, 80, which are erected with the axis line in the left-right direction in the mission main body 43, are interlockingly connected to the second power transmission shaft 79 for turning, and each turning is performed. For third
The outer ends of the transmission shafts 80, 80 are linked to the ring gears 72, 72 of the planetary gear mechanisms 51, 51, respectively.

Here, the turning output gear 81 attached to the turning output shaft 77 is meshed with the large diameter transmission gear 82 rotatably attached to the turning input shaft 75, and is integrally formed with the large diameter transmission gear 82. The small-diameter transmission gear 83 is engaged with the turning first input gear 84 attached to the turning first transmission shaft 78, and the turning first input gear 84 is engaged.
The first output gear 85 for rotation attached to the transmission shaft 78 is engaged with the second input gear 86 for rotation attached to the second transmission shaft 79 for rotation, and is attached to the rear end portion of the second transmission shaft 79 for rotation. The second swivel output bevel gear 87 is engaged with the third swivel input bevel gears 88, 88 attached to the inner ends of the pair of left and right third swivel transmission shafts 80, 80, and the third swivel shaft 80 for each swivel is engaged. The third output gear 89,89 mounted on the outer end of the
The ring gears 72, 72 are meshed with each other via 0, 90.

Here, in the planetary gear mechanism 51, a primary gear 91 is provided between the sun gear 52 and the ring gear 72, and a drive wheel support shaft is provided in the primary gear 91 via a cage 92.
17 are linked together.

In this way, the power transmitted from the power transmission system 45 for straight traveling to the sun gears 52, 52 and the power transmission system 4 for turning
The power transmitted from 6 to the ring gears 72, 72 is merged by the primary gears 91, 91, and the resultant force is transmitted to the left and right drive wheel support shafts 17, 17.

As shown in FIG. 5, the PTO power transmission system 47 is installed on the input shaft 49 provided on the front cover 42 of the transmission and in the axle case 24 with its axis lined in the front-rear direction.
PTO with rear end protruding rearward from axle case 24
It is interposed between the shaft 93.

In the transmission front cover 42, the PTO input gear is attached to the second output gear 94 attached to the input shaft 49 via the PTO intermediate gear 95 attached to the second intermediate shaft 76.
96 meshes with each other, and the input gear 96 for the PTO is a PT installed in the transmission front cover 42 with its axis lined in the front-rear direction.
It is attached to the O input shaft 97.

Moreover, the PTO input shaft 97 is provided with the first transmission shaft for PTO, which is erected with the axis line in the front-rear direction in the mission main body 43 through the PTO clutch 98 arranged in the mission intermediate section 44. 99 linked together, the first for the same PTO
The transmission shaft 99 is interlockingly connected to the above-mentioned PTO shaft 93 through a PTO speed-changing shaft 100 that is installed in the mission main body 44 with its axis oriented in the front-rear direction.

Further, the first transmission shaft 99 for PTO has a first
~ While attaching the 4th output gear 101, 102, 103, 104, P
The first to third transmission gears 105, 106 and 107 which mesh with the first to third output gears 101, 102 and 103, respectively, and the reverse gear 108 which meshes with the fourth output gear 104 through the counter gear 109 are meshed with the TO speed change shaft 100. The counter gear 109 is attached to a counter shaft 110 that is installed in the transmission main body 43 with its axis oriented in the front-rear direction. 111 and 112 are the first and second PTs
It is a shift operation shifter for O.

In this way, by operating the first and second PTO speed change operation shifters 111, 112 to switch the connection to any of the first to third speed change gears 105, 106, 107, the PTO shaft 93 is rotated forward by three rotations. The PTO shaft 93 can be rotated in reverse by operating the second PTO gear shift operation shifter 112 to switch the connection to the reverse gear 108 while the gear can be shifted in stages.

As shown in FIG. 5, the pump driving power transmission system 48 has its axis lined in the front-rear direction across the input shaft 49 provided on the mission front lid portion 42, the mission front lid portion 42 and the mission intermediate portion 44. The tandem charge pump P is interlockingly connected to the pump drive shaft 114 that is installed over the pump drive shaft 114 so that the charge pump P can be driven.

Then, in the transmission front cover 42, to the second output gear 94 attached to the input shaft 49, to the pump drive shaft 114 via the pump drive intermediate gear 115 attached to the first intermediate shaft 57. The attached pump drive input gear 116 is meshed.

As shown in FIGS. 6 and 10, a charge oil passage 117 connected to the charge pump P is formed in the mission front wall portion 42, and the straight HST 6 and the turning HST 7 are passed through the charge oil passage 117. Each charge port 118,11
While connecting 9 to each other, HST6 for straight ahead and H for turning
The return ports 120 and 121 of ST7 are connected to each other through a return oil passage 122, and the end portion of the return oil passage 122 is connected to the mission main body 43 as a hydraulic oil tank.

In this way, the straight HST 6 and the turning HS
The front wall of the mission 4 between the charge ports 118 and 119 of T7
Since they are connected to each other through the charge oil passage 117 formed in 2, the oil supply pipes can be reduced as much as possible and the supply oil passages can be integrated.

In this embodiment, since the mission unit 5 is constructed as described above, the following actions and effects are produced.

That is, the transmission system as a whole can be compactly arranged in the mission section 5, and the transmission section 45 and the turning power transmission system can be simply installed on the vehicle body frame 2. All the transmission systems of the system 46, the PTO power transmission system 47, and the pump drive power transmission system 48 can be easily assembled.

At this time, the mission unit 5 includes the mission front cover unit 42 and the mission body unit integrated with the axle case 24.
43, these mission front lid 42 and mission body 43
And a transmission intermediate portion 44 provided between the transmission E and the transmission front cover portion 42 from the engine E. Since the power transmission system 46 for turning and the power transmission system 47 for PTO are branched and transmitted, each power transmission system 45, 46, 47 in the mission main body 43.
Can be systematically branched, and the dead space in the axial direction can be reduced. As a result, the mission unit 5 can be made compact.

Moreover, the HST 6 for straight ahead is installed in the mission section 5.
Since the turning HST 7 and the turning HST 7 are interlockingly connected in parallel, the straight-movement operating mechanism 128 and the turning operating mechanism 126, which are the operating systems of the both HSTs 6 and 7, which will be described later, can be arranged in the parallel state. The operation mechanisms 128 and 126 can be arranged compactly and can be operated reliably.

Further, since the parking brake 70 and the PTO clutch 98 are arranged in the middle portion 44 of the mission, it is necessary to provide a protective cover for protecting the parking brake 70 and the PTO clutch 98 from scattered dirt and the like. No, and
By removing the mission front lid portion 42, maintenance and the like can be easily performed.

The upper surface of the mission unit 5 is shown in FIGS.
As shown in FIG. 7, a lift arm support 170 is provided, a recess 171 is formed in the center of the lift arm support 170, and lifting hydraulic valves 172 as various hydraulic valves are provided in the recess 171.
And a rolling control hydraulic valve 173 are arranged side by side.

In this way, the lifting hydraulic valve 172 and the rolling control hydraulic valve 173 as various hydraulic valves are provided.
Is disposed in the recess 171 formed on the upper surface of the mission unit 5, so that even when the driver's seat 35 of the driver's unit 4 is arranged above the mission unit 5, the ground clearance of the driver's seat 35 is reduced. It can be set low, and the center of gravity of the entire vehicle body including the weight of the operator seated in the driver's seat 35 can be set as low as possible, resulting in improved running stability of the vehicle body. Can be made.

At the rear part of the lift arm support 170, the base ends of a pair of left and right lift arms 174, 174 are pivotally supported by a lift arm support shaft 175 whose axis is oriented in the left-right direction, and the middle parts of the lift arms 174, 174 are formed. , Rear axle case 2
Lift cylinders 177 and 177 that extend and contract in the vertical direction are provided between the cylinder stays 176 and 176 that project rearward and downward from the left and right side rear portions of 4.

In this way, the lift arms 174,174
In addition, various working machines (not shown) are mounted via a top link stay 178 and a lower link 179 as a lifting connection mechanism shown in FIG.
By connecting the above, various connected working machines can be appropriately moved up and down.

As shown in FIGS. 2 and 3, the turning operation mechanism 1 is attached to the trunnion arm 125 of the turning HST 7.
While the steering wheel 34 is interlockingly connected via 26, the trunnion arm 127 of the straight HST6 is
The forward / reverse switching lever 40 is interlocked via the straight-movement operating mechanism 128, and a turning operation booster 129 is provided in the middle of the turning operation mechanism 126, and the turning operation booster 129 is provided. While arranging in parallel with the turning HST 7, the booster 130 for straight ahead operation is provided in the middle of the straightforward operation mechanism 128, and the booster 130 for straight ahead operation is provided in the straight ahead HST 7.
6 is arranged in parallel.

That is, the turning operation booster 129 has a stay 131 on the inner surface of the middle portion of the left body frame forming piece 23.
The turning force booster 129 is mounted in a cylinder 133 that extends in the front-rear direction and has an oil sump chamber 132 in the central portion, as shown in FIGS. , A spool 134 extending in the front-rear direction is slidably inserted in the front-rear direction, a piston 135 is attached to the center of the spool 134, and an outer peripheral surface of the piston 135 is slidable on an inner peripheral surface of the cylinder 133. The front oil chamber 136 abutted against and partitioned by the piston 135 in the same cylinder 133
And a rear oil chamber 137 are formed, and both the front and rear oil chambers 136, 137 are communicatively connected via a supply communication oil passage 138 formed on the peripheral wall of the cylinder 133, and a booster is provided to the supply communication oil passage 138. A hydraulic oil supply pipe 140 that forms a supply oil passage 139 is communicatively connected.

The spool 134 is located near the left body frame forming piece 23, and is located at the same position as the body frame forming piece 23.
The front end of the spool 134 is interlockingly connected to an upstream connecting rod 164 as an interlocking operation tool forming an upstream side of the turning operation mechanism 126. ing.

In this way, the piston 135 is slid subtly due to the pressure difference in the oil supply passage caused by the sliding of the spool 134, and the turning HST 7 is operated in proportion to the operation amount of the steering wheel 34. It is possible to improve the operability.

At this time, since the turning operation booster 129 is arranged in parallel with the turning HST 7, it can be connected in a compact and reliable interlocking manner via the turning operation mechanism 126. The operability can be improved from the point as well.

Further, as shown in FIG. 10, the booster supply oil passage 139 is formed by branching from the charge oil passage 117 for supplying hydraulic oil from the charge pump P to the straight-travel HST 6 and the turning HST 7. Therefore, the hydraulic oil is supplied to the turning operation booster 129 through the same booster supply oil passage 139.

In this way, the booster supply oil passage 139 can be formed as short as possible, and the charge oil passage 117 for supplying hydraulic oil to the turning HST 7 through the booster supply oil passage 139. The hydraulic fluid can be reliably supplied to the turning operation booster 129, and the turning operation booster 12
9 functions can be well secured.

As shown in FIG. 8, oil passage throttle portions 141 and 142 are provided at the front and rear ends of the supply communication oil passage 138, and the front and rear oil chambers 136 and 136 are respectively passed through the oil passage throttle portions 141 and 142. 1
By supplying hydraulic oil to 37, the hydraulic oil can be supplied at a substantially constant pressure.

As shown in FIGS. 7 and 8, a neutral state holding spring 145 as an elastic means for holding the neutral state is interposed between the inner surface 143 of the front wall of the cylinder 133 and the front surface 144 of the piston 135. A neutral state holding spring 148 as an elastic means for holding the neutral state is interposed between the inner surface 146 of the rear wall of the cylinder 133 and the rear surface 147 of the piston 135,
When there is no pressure difference between the front and rear oil chambers 136 and 137, the two neutral state holding springs 145 and 148 are used to hold the piston 135 in the neutral state, which is the central portion of the cylinder 133.

Therefore, when the steering wheel 34 and the forward / reverse switching lever 40 are not operated, it is ensured that the pistons 135, 135 are reliably held in the neutral state by the neutral state holding springs 145, 148, and the HSTs 6, 7 malfunction. Can be prevented.

In the center portion on the left and right sides of the peripheral surface of the spool 134,
As shown in FIGS. 7 to 9, the communication slits 150, 150 are formed by chamfering, and both communication slits 150, 150 are
Formed by extending the spool 134 in the axial direction,
By forming the front and rear surfaces 144, 147 of the piston 135 to have substantially the same width as the front-rear width, and connecting both the communication slits 150, 150 with the oil sump chamber 132 via the communication oil passage 156 formed in the central portion of the piston 135, As shown in FIG. 10, a switching valve is configured. Reference numeral 151 is a spool return spring, 152 is a spool return spring accommodating chamber, 153 and 154 are leak oil recovery paths communicating with the oil sump chamber 132, and 155 is a hydraulic oil return pipe connected to the oil sump chamber 132.

In this way, when the piston 135 is moved through the spool 134 in either the front or rear direction, for example, backward, and the communication slits 150, 150 communicate with the rear oil chamber 137, the rear oil chamber 137 operates. Oil communication slit 150,150
→ Communication oil passage 156 → Oil sump chamber 132 → Outflow into the hydraulic oil tank (transmission main body 43 in this embodiment), and rear oil chamber 13
The internal pressure of 7 becomes small.

At this time, the hydraulic oil is supplied from the charge pump P to the charge oil passage 117 → the booster supply oil passage 139 → the supply communication oil passage.
138 → oil passage throttle parts 141, 142 → supplied to the front and rear oil chambers 136, 137.

As a result, a pressure difference (pressure difference in the supply oil passage) is generated between the internal pressure of the front oil chamber 136 and the internal pressure of the rear oil chamber 137, and the spool 134 is moved backward by the pressure oil. be able to.

Therefore, when the turning HST 7 is operated by the steering wheel 34 via the turning operation mechanism 126, the operation load of the turning HST 7 is applied by the turning booster 129 provided in the middle of the turning operation mechanism 126. Therefore, the turning HST 7 can be operated with a slight operation load.

A reverse load (so-called kickback) due to the load on the turning HST 7 causes a turning operation mechanism 126.
Even when it acts on, the turning booster 129 has a cushioning function, and the operability of the steering wheel 34 can be excellently secured.

Further, as shown in FIGS. 7 and 9, an arm support shaft 160 having an axis lined in the left-right direction is provided in the upper center part of the cylinder 133 so as to be rotatable around the axis line. The upper end of the piston interlocking arm 161 arranged in the oil sump 132 is connected to the base end of the piston 135, and the lower end of the piston interlocking arm 161 is engaged with the central portion of the piston 135 to form the piston 135. The piston interlocking arm 161 is rotated in the front-rear direction in conjunction with the forward and backward sliding of the.

The tip end of the arm support shaft 160 is projected rightward outward from the cylinder 133, and the lower end of the operating arm 162 is interlockingly connected to the tip end, and the upper end of the operating arm 162 and the trunnion arm are connected. A downstream side connecting rod 163 as an interlocking operation tool that forms a downstream side portion of the turning operation mechanism 126 is provided between the connecting rod 163 and 125.

The straight-ahead operation booster 130 is attached to the inner surface of the right-hand side body frame forming piece 23 with a mounting bolt 149 via a stay 131. It has the same basic structure as the operation booster 129, and is configured to be symmetrical to the turning operation booster 129 so that it is attached to the body frame forming piece 23 on the right side. is there.

Therefore, the basic operation of the booster 130 for straight-ahead operation is set to be the same as that of the booster 129 for turning operation.
The trunnion arm 127 of the straight HST 6 can be easily operated.

That is, when the forward / reverse switching lever 40 is used to operate the straight-travel HST 6 via the straight-travel operation mechanism 128, the straight-travel booster 130 provided at a midway portion of the straight-travel operation mechanism 128 is used to drive the straight-travel HST 6. The operation load can be reduced, and the straight-travel HST 6 can be operated with a slight operation load.

A reverse load (so-called kickback) due to the load on the straight-travel HST 6 causes a straight-travel operation mechanism 128.
Even when it acts on, the linearly moving power booster 130 fulfills a cushioning function, and the operability of the forward / backward switching lever 40 can be ensured satisfactorily.

FIG. 10 shows a hydraulic circuit section B of a traveling vehicle A according to the present invention. The hydraulic circuit section B includes a tandem type charge pump P, a straight-travel HST 6 and a booster for straight-travel operation. 130, turning HST 7, turning operation booster 129, PTO clutch 98, and lift cylinder 177.
, The swing cylinder 180 and the external hydraulic pressure take-out portion 181 are connected in parallel. P1 is a straight-moving pump, M1 is a straight-moving motor, P2 is a swing pump, M2 is a swing motor, 182 is a flow divider, 183 is a swing valve, and 184 is an electromagnetic proportional valve section.

[0082]

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

(1) According to the present invention as set forth in claim 1, a continuously variable transmission for turning and a linearly variable transmission are interlockingly connected to the mission section, and the continuously variable transmission for turning is provided with a turning operation mechanism. While the steering wheel is interlockingly connected, the forward / reverse switching lever is interlockingly connected to the straight-ahead transmission via the straight-ahead operation mechanism, and a boosting device for a turning operation is provided in the middle of the turning operation mechanism, while a straight-ahead drive is provided. A booster for straight-ahead operation is provided in the middle of the operation mechanism.

As described above, when the steering continuously variable transmission is operated by the steering wheel through the turning operation mechanism, the turning booster provided in the middle of the turning operation mechanism is used for turning continuously variable. The operation load of the transmission can be reduced, and the turning continuously variable transmission can be operated with a slight operation load.

Even when a reverse load (so-called kickback) acts on the turning operation mechanism due to the load on the turning continuously variable transmission, the turning booster functions as a buffer to operate the steering wheel. It is possible to ensure good performance.

Further, when the forward / reverse switching lever is used to operate the straight traveling transmission mechanism through the straight traveling operation mechanism, the operation load of the straight traveling transmission device is increased by the straight traveling booster provided in the middle portion of the straight traveling operation mechanism. Therefore, the linear transmission can be operated with a slight operation load.

Even when a reverse load (so-called kickback) acts on the straight-ahead operation mechanism due to the load on the straight-ahead transmission, the straight-ahead operation booster functions as a buffer function, and the forward-reverse switching lever is operated. Good operability can be ensured.

(2) In the present invention as set forth in claim 2, the turning operation booster and the interlocking operation tool of the turning operation booster, the straight advance operation booster and the straight advance operation booster are interlocked. The operation tools are arranged along the vicinity of the left and right vehicle body frame forming pieces which are respectively extended and arranged in the front-rear direction.

In this way, when each booster operates, it is possible to prevent each interlocking operation tool from malfunctioning due to interference with other arrangements and the like. The outer side can be protected from scattered mud by the left and right body frames.

Each booster is hydraulically operated,
The hydraulic oil is supplied to each booster via a booster supply oil passage formed by branching from a charge oil passage to the transmission.

In this way, the booster supply oil passages can be formed as short as possible, and the booster supply oil passages are surely operated from the charge oil passages of the transmission to the respective boosters. Oil can be supplied, and the function of each booster can be ensured satisfactorily.

(3) In the present invention according to claim 3, a continuously variable transmission for turning and a linearly variable transmission are interlocked and linked to the transmission section, and the continuously variable transmission for turning is provided through a turning operation mechanism. While connecting the steering wheel in an interlocking manner, the forward / reverse switching lever is interlockingly connected to the straight-ahead transmission via the straight-ahead operation mechanism, and a turning operation booster is provided in the middle of the turning operation mechanism. The booster for turning operation is placed in parallel with the continuously variable transmission for turning, while the booster for straight-ahead operation is installed in the middle of the straight-ahead operation mechanism, and the booster for straight-ahead operation is used for straight-shifting. Each booster is arranged in parallel with the device, and each booster includes a spool that is interlocked with the upstream side of each operating mechanism and a piston that slides due to the pressure difference in the supply oil passage that occurs as the spool slides. , The base end is linked to each piston Rutotomoni, and a working arm which is operatively connected to the distal end portion on the downstream side of each operating mechanism.

In this way, the piston is delicately slid due to the pressure difference in the oil supply passage caused by the sliding of each spool, and each shift is made proportional to the operation amount of the steering wheel or the forward / reverse switching lever. The device can be operated and the operability can be improved.

At this time, since the respective boosters are arranged in parallel with the respective transmissions, they can be connected in a compact and reliable interlocking manner through the respective operating mechanisms. Can be improved.

(4) According to the fourth aspect of the present invention, the piston is slidably fitted to the outer peripheral surface of the spool midway portion, and maintains the neutral state in the state where there is no pressure difference in the oil supply passage. As described above, elastic means for maintaining the neutral state is provided on both sides of the piston.

In this way, when the steering wheel or the forward / reverse switching lever is not operated, it is possible to securely prevent the pistons from being reliably held in the neutral state by the elastic means for holding the neutral state and erroneously operating each transmission. can do.

[Brief description of drawings]

FIG. 1 is a side view of a traveling vehicle according to the present invention.

FIG. 2 is a plan view of a mission section of the traveling vehicle.

FIG. 3 is a side view of the mission unit.

FIG. 4 is a front view of the mission unit.

FIG. 5 is a conceptual explanatory diagram of a power transmission system in the mission unit.

FIG. 6 is a hydraulic circuit diagram.

FIG. 7 is a sectional side view of the booster.

FIG. 8 is a cross-sectional plan view of the booster device.

FIG. 9 is a sectional rear view of the booster device.

FIG. 10 is a hydraulic circuit diagram.

[Explanation of symbols]

A traveling vehicle 1 running section 2 body frame 3 prime mover department 4 Driving department 5 Mission Department

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsumi Fujiki             428 Enami, Okayama City, Okayama Prefecture Seirei Industry Co., Ltd.             Within the corporation F-term (reference) 2B043 AA03 AB08 BA02 BB01 DA04                       DB02 DB09 DC01                 3D052 AA16 EE01 FF01 FF02 GG03                       JJ03 JJ10 JJ21 JJ22 JJ31                       JJ35                 3J053 AB03 AB21 AB32 DA21 DA22                       EA12 FB03                 3J067 AA02 AA24 AA27 AB01 AB11                       AC42 BA27 DA52 DB02 DB12                       FA06 FA82 FB63 GA12

Claims (4)

[Claims] 1. A continuously variable transmission for turning in a mission section (5)
(7) and the linear transmission (6) are interlockingly connected, and the steering wheel (34) is interlockingly connected to the turning continuously variable transmission (7) through the turning operation mechanism (126). Straight transmission
Forward / reverse switching lever (4
(0) are interlockingly connected, and a turning operation booster (129) is provided in the middle of the turning operation mechanism (126), while a straightening operation booster (129) is provided in the middle of the rectilinear operation mechanism (128). 130) provided with a traveling vehicle. 2. A swivel booster (129), an interlocking operation tool of the swivel booster (129), and a straight forward booster.
(130) and the interlocking operation tool of the booster for straight-line operation (130),
Each of the boosters (129, 130) is hydraulically actuated, and the boosters (129, 130) are hydraulically operated. Booster formed by branching from charge oil passage (117, 117) to 6, 7) Each booster via supply oil passage (139, 139)
The traveling vehicle according to claim 1, wherein hydraulic oil is supplied to (129, 130). 3. A continuously variable transmission for turning in the mission section (5)
(7) and the linear transmission (6) are interlockingly connected, and the steering wheel (34) is interlockingly connected to the turning continuously variable transmission (7) through the turning operation mechanism (126). Straight transmission
Forward / reverse switching lever (4
(0) are interlockingly connected, a turning operation booster (129) is provided in the middle of the turning operation mechanism (126), and the turning operation booster (129) is used for the turning continuously variable transmission ( 7) is arranged in parallel with the other, while a linear operation booster (130) is provided in the middle of the linear operation mechanism (128).
In addition, the booster device for straight ahead operation (130) is arranged in parallel with the transmission device for straight ahead (6). Connected spools (134,134) and each spool (13
The piston (135, 135) that slides due to the pressure difference in the supply oil passage that occurs due to the sliding of (4, 134) and the proximal end portion of each piston (135, 135) are linked and connected, Arm (162, 162) with the tip part interlockingly connected to the part
And a traveling vehicle. 4. The piston (135) is slidably fitted to the outer peripheral surface of the spool (134) in the middle thereof, and is kept in a neutral state when a pressure difference is not generated in the oil supply passage. The traveling vehicle according to claim 3, wherein elastic means (145, 148) for maintaining a neutral state are provided on both sides of the piston (135).