JP2003291845A - Traveling vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve traveling stability of a car body. <P>SOLUTION: In this traveling vehicle, a car body frame is interposed between a pair of right and left traveling part, and the car body frame is provided with a prime mover part and a transmission part connected to the prime mover part to interlock with each other. A power transmission system for rectilinear motion, a power transmission system for turning, a power transmission system for PTO and a power transmission system for driving a pump are integrally disposed in the transmission part. A recessed part is formed in the top surface of the transmission part, and various hydraulic valves are disposed in the recessed part. The various hydraulic valves are thus disposed in the recessed part formed on the top surface of the transmission part, whereby even if a driver's seat of a driving part is disposed in an upper position of the transmission part, the ground clearance of the driver's seat can be set low so that the position of center of gravity of the whole car body including the weight of an operator seated on the driver's seat can be set in a lower position as much as possible. <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, a body frame is provided between a pair of left and right traveling portions, and a prime mover portion and a mission portion interlockingly connected to the prime mover portion are provided in the same body frame. A hydraulic case is provided on the upper surface of the mission part,
There is a hydraulic case in which a pair of left and right lift arms are provided in an interlocking manner so that various working machines can be lifted and lowered by the lift arms via a lifting link mechanism.

Various hydraulic valves are provided on the upper surface of the mission section so that the hydraulic operating section can be controlled through the various hydraulic valves.

Further, a driver's seat of the driver's seat is arranged above the mission unit so that an operator can sit on the driver's seat to perform a steering operation.

[0005]

However, in the above-described traveling vehicle, various hydraulic valves are arranged on the upper surface of the mission section, and therefore the driver's seat of the driver section arranged above the mission section. In order to prevent the vehicle from interfering with various hydraulic valves, the ground clearance of the driver's seat must be set high, and the entire vehicle body including the weight of the operator sitting directly in the driver's seat must be set accordingly. The center of gravity of the vehicle becomes high, which adversely affects the running stability of the vehicle body.

[0006]

Therefore, in the present invention, a vehicle body frame is provided between a pair of left and right running portions, and a prime mover portion and a mission portion interlockingly connected to the prime mover portion are provided in the body frame. In a traveling vehicle, a straight drive power transmission system, a turning power transmission system, a PTO power transmission system, and a pump drive power transmission system are integrally provided in a mission unit, and an axle case is integrally provided in the mission unit. The present invention provides a traveling vehicle characterized in that a concave portion is formed on the upper surface of the mission portion, and various hydraulic valves are arranged in the concave portion.

Further, according to the present invention, in a traveling vehicle in which a body frame is provided between a pair of left and right traveling portions, and a prime mover portion and a mission portion interlockingly connected to the prime mover portion are provided in the vehicle body frame, The transmission shaft is arranged in the front-rear direction of the vehicle body, and the axle case is extended outward from the mission part toward the left and right sides, and the drive shaft is arranged in the axle case with the axis line in the left-right direction. The transmission shaft is interlocked with the same drive shaft, and planetary gear mechanisms are provided on the left and right sides of the drive shaft, respectively, and the left and right drive wheels are interlocked with each other via the planetary gear mechanisms.

[0008]

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

That is, the traveling vehicle according to the present invention has, as a basic structure, a body frame interposed between a pair of left and right traveling portions, a prime mover portion on the body frame, and a mission portion interlockingly connected to the prime mover portion. Is provided.

As a characteristic structure, the power transmission system for straight traveling, the power transmission system for turning, the power transmission system for PTO, and the power transmission system for pump drive are integrally provided in the mission unit, and the mission unit is also provided. An axle case is integrally connected to the above, a recess is formed on the upper surface of the mission portion, and various hydraulic valves are arranged in the recess.

Further, a transmission shaft is arranged in the mission portion with its axis oriented in the front-rear direction of the vehicle body, and the axle case is extended outward from the mission portion in the left and right directions. Align the axis to
The transmission shaft is interlocked with the drive shaft, and planetary gear mechanisms are provided on the left and right sides of the drive shaft, respectively, and the left and right drive wheels are interlocked with each other via each planetary gear mechanism.

[0012]

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 traveling 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.

The body frame 2 is, as shown in FIGS. 1 to 4, 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 middle parts of the pair of left and right body frame forming pieces 23, 23 are fixed on the front connecting frame 21, and the left and right pair of left and right traveling frames 10, 10 are erected above the rear parts of the 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 a midway 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 traveling power transmission system 45, a turning power transmission system 46, a PTO power transmission system 47, and a pump driving 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,
It is interposed between a drive shaft 50 that is installed in the axle case 24 with its axis lined in the left-right direction, and is arranged at the left and right end portions of the drive shaft 50 at the left and right side portions within the axle case 24. The sun gears 52, 52 of the planetary 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 43 with their axes oriented in the front-rear direction so as to be parallel to 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 straight-shift operation shifter 113, it is possible to change the speed between the high speed and the low speed.

A parking brake 70 is connected in series at the front end of the straight-moving speed change shaft 60, and the parking brake 70 is arranged 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-back 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 straight drive power transmission system 45 to the sun gears 52, 52 and the turning power transmission system 4
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 power transmission system 47 for the PTO 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 a PTO first transmission shaft laid in the transmission main body portion 43 with its axis oriented in the front-rear direction via the PTO clutch 98 arranged in the transmission intermediate portion 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 and 112 to switch the connection to any of the first to third speed change gears 105, 106 and 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 drive power transmission system 48 has its axis lined in the front-rear direction across the input shaft 49 provided on the mission front cover 42, the mission front cover 42 and the mission intermediate part 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.

In the transmission front lid portion 42, the pump drive shaft 114 is attached to the second output gear 94 attached to the input shaft 49 via the pump drive intermediate gear 115 attached to the first intermediate shaft 57. The pump driving input gear 116 attached to the gear is engaged.

Further, as shown in FIGS. 6 and 10, a charge oil passage 117 connected to the charge pump P is formed in the front wall portion 42 of the mission, and the HST 6 for straight traveling and the HST 7 for turning are connected 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.

Thus, 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 section 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 unit 5, and by simply attaching the mission unit 5 to the vehicle body frame 2, the power transmission system 45 for straight traveling and the power transmission for turning are transmitted. 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 traveling 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 of each lift arm 174, 174 , 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 part 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 at the same position.
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 slightly slid due to the pressure difference in the oil supply passage generated as the spool 134 slides, 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 end portions 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.

Further, 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 to either the front or rear direction, for example, rearward via the spool 134 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 working 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) occurs 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 actuating arm 162 is interlockingly connected to the tip end, and the upper end of the actuating 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 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 in the middle of the straight-travel operation mechanism 128 operates the straight-travel HST 6 to move 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 portion B of a traveling vehicle A according to the present invention. The hydraulic circuit portion B includes a tandem type charge pump P, a HST 6 for straight traveling and a booster for straight traveling 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.

[0078]

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

(1) In the present invention according to claim 1, a vehicle body frame is provided between a pair of left and right running portions, and a prime mover portion and a mission portion interlockingly connected to the prime mover portion are provided on the body frame. In a traveling vehicle, a straight power transmission system, a turning power transmission system, a PTO power transmission system, and a pump driving power transmission system are integrally arranged in a mission unit, and
Axle case is integrally connected to the mission part,
A recess is formed on the upper surface of the mission part, and various hydraulic valves are arranged in the recess.

Since the various hydraulic valves are thus arranged in the recess formed on the upper surface of the mission unit, even when the driver's seat of the driver unit is arranged above the mission unit, the same operation is performed. The ground clearance of the seat 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 can be set as low as possible. The stability can be improved.

(2) According to the present invention as set forth in claim 2, the transmission shaft is arranged in the mission portion with its axis oriented in the front-rear direction of the vehicle body, and the axle case is extended from the mission portion to the left and right outer sides. The drive shaft is arranged in the same axle case with the axis line oriented in the left-right direction, and the transmission shaft is interlockingly connected to the drive shaft, and planetary gear mechanisms are provided on the left and right side portions of the drive shaft, respectively. The left and right drive wheels are interlockingly connected via.

In this way, the mission part and the axle case can be integrally molded compactly, and the mission part and the axle case can be easily and surely attached to the vehicle body frame.

[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    F term (reference) 3D052 AA05 AA16 BB01 BB10 BB11                       DD01 DD03 EE01 FF01 GG03                       HH01 HH02 JJ10 JJ21 JJ22                       JJ25 JJ31 JJ35

Claims (2)

[Claims] 1. A vehicle body frame (2) is interposed between a pair of left and right traveling portions (1, 1), and a motor part (3) is provided on the vehicle body frame (2).
In a traveling vehicle provided with a transmission section (5) interlockingly connected to the prime mover section (3), a straight drive power transmission system (45), a turning power transmission system (46), and a PTO are used in the mission section (5). The power transmission system (47) and the pump driving power transmission system (48) are integrally arranged, and the axle case (24) is integrally connected to the mission section (5). A traveling vehicle characterized in that a concave portion (171) is formed on the upper surface of (5) and various hydraulic valves are arranged in the concave portion (171). 2. A vehicle body frame (2) is provided between a pair of left and right traveling portions (1, 1), and a motor part (3) is provided on the vehicle body frame (2).
In a traveling vehicle provided with a transmission section (5) linked to the prime mover section (3), the transmission shaft is arranged in the transmission section (5) with its axis oriented in the longitudinal direction of the vehicle body. ), The axle case (24) is extended outward from the left and right, and the drive shaft (50) is arranged in the axle case (24) with its axis lined in the left-right direction. In addition to interlocking the transmission shaft,
Planetary gear mechanism (51, 51) on the left and right sides of the drive shaft (50)
And the left and right drive wheels through each planetary gear mechanism (51, 51).
A traveling vehicle characterized in that (13, 13) are linked together.