JPH1191379A - Work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure of a vehicle body frame by arranging a static hydraulic continuously variable transmission between an engine and a travel transmission case, and forming the vehicle body frame with a speed change case. SOLUTION: A travel main transmission 20 is provided with a hydraulic pump and a hydraulic motor in a speed change case 21 to form a static hydraulic continuously variable transmission. The front end section of the speed change case 21 constituting the travel main transmission 20 is connected to the rear end of a main clutch housing 10. A vehicle body frame is formed with an engine E, a front frame 8, the main clutch housing 10, a travel transmission case 5, and the speed change case 21. The structure of the vehicle body frame is thereby simplified, and the upper section of the vehicle body frame can be made low in height and the bottom section can be made high between the engine E and the travel transmission case 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work vehicle such as an agricultural tractor, more specifically,
The present invention relates to a work vehicle provided with a traveling transmission case in a state where a body frame is formed on the other end side.

[0002]

2. Description of the Related Art In an agricultural tractor as an example of the working vehicle, a transmission frame in which a front end side is connected to an engine and a front transmission connected to a rear portion of the engine, as disclosed in, for example, Japanese Patent Application Laid-Open No. 7-329587. A vehicle body frame is formed by a rear transmission or the like connected to the rear end side of the transmission frame, a hydraulic stepless transmission is provided inside the transmission frame, and the engine output is shifted by the stepless transmission to change the rear portion. Some were to be transmitted to missions.

[0003]

According to the above-mentioned prior art, it is necessary to separately form the vehicle body frame and the transmission, which complicates the structure. In addition, the problem that the ground height at the top of the vehicle body becomes high and the ground height at the bottom of the vehicle body becomes low tended to occur. SUMMARY OF THE INVENTION An object of the present invention is to provide a work vehicle that can easily change gears while easily avoiding the above-mentioned problems.

[0004]

The constitution, operation and effect of the invention according to claim 1 are as follows.

[Structure] The engine is mounted on one of the front and rear ends of the vehicle body.
In a work vehicle equipped with a traveling transmission case in a state where a body frame is formed on the other end side, a hydrostatic type transmission in which engine output is shifted by a hydraulic pump and a hydraulic motor and transmitted to a transmission in the traveling transmission case. A step transmission is disposed between an engine and a transmission transmission case, and the body frame is formed by a transmission case provided to form an oil chamber that houses a hydraulic pump and a hydraulic motor in the hydrostatic stepless transmission. It is formed.

[Operation] The continuously variable transmission is provided with its transmission case being a body frame portion between the engine and the traveling transmission case. The upper level of the body frame portion is as low as possible and the bottom level is as low as possible. The vehicle body frame is formed while being raised, and the engine output is continuously changed and transmitted for traveling.

[Effect] In the case where the vehicle can travel while shifting easily by the continuously variable transmission, the structure can be obtained simply by using the transmission case also as the body frame. Furthermore, the height of the top of the body frame between the engine and the traveling transmission case is made as low as possible and the height of the bottom is made as high as possible, so that the driver deck is low and it is easy to get on and off, even if the bottom of the body is high and it is uneven, It is possible to obtain an advantageous state, such as easy running with less contact with the protrusion.

The structure, operation and effect of the invention according to claim 2 are as follows.

[Structure] In the structure according to the first aspect of the invention, the transmission case is connected to a main clutch housing connected to a rear portion of the engine and the traveling transmission case.

[Operation] The vehicle body frame can be formed in a state in which the transmission case is connected to the main clutch housing and the traveling transmission case to exhibit excellent frame strength.

[Effect] What can be advantageously obtained in terms of structure and ground height by using the transmission case as a body frame can be obtained in an excellent state in terms of frame strength.

The structure, operation and effect of the invention according to claim 3 are as follows.

[Structure] In the structure of the invention according to claim 2, the speed change case is formed integrally with the main clutch housing.

[Operation] The transmission case and the main clutch housing can be formed at once in a state where they are firmly connected by integral molding.

[Effect] It is possible to obtain a frame having a more excellent frame strength from the viewpoint of the connection strength between the transmission case and the main clutch housing. In addition, the transmission case and the main clutch housing can be formed at once, and can be easily manufactured.

The structure, operation and effect of the invention according to claim 4 are as follows.

[Structure] In the structure of the present invention according to any one of claims 1 to 3, the hydraulic pump and the hydraulic motor are arranged side by side in the vehicle body in the speed change case.

[Operation] It is possible to obtain the transmission while reducing the vertical height of the transmission case as compared with the case where the pump and the motor are arranged in the vertical direction of the vehicle body.

[Effect] In addition to using the transmission case as the body frame, the vertical height of the transmission can be reduced. Therefore, the top height of the body frame is low, the bottom height is high, and the vehicle can get on and off. Can be made more advantageous.

The structure, operation and effect of the invention according to claim 5 are as follows.

[Structure] In the structure of the present invention according to any one of claims 1 to 4, an operation unit for changing the swash plate angle of the hydraulic pump is arranged on a lateral side of the transmission case. .

[Operation] It is possible to obtain a transmission in which the vertical height of the transmission case is smaller than when the operation unit is disposed at the top or bottom of the transmission case.

[Effect] In addition to using the transmission case as a vehicle body frame and arranging the pump and the motor in the lateral direction of the vehicle, the vertical height of the transmission case can be reduced by the surface of the operation unit. Accordingly, the height of the upper portion of the body frame is as low as possible and the height of the bottom portion is as high as possible, so that a state in which getting on and off and running can be more advantageously obtained.

The structure, operation and effect of the invention according to claim 6 are as follows.

[0025] [Structure] In the structure of the invention according to claim 5, a servo cylinder and a servo valve for changing the swash plate angle of the hydraulic pump are provided in the operating section, and the longitudinal direction of the servo cylinder and the servo valve is adjusted in the vertical direction of the vehicle body. Along the direction.

[Operation] When the servo valve is operated, the servo cylinder is driven to change the swash plate angle and shift the gear. In addition, the cylinder and the valve can be arranged on the lateral side of the transmission case so that the cylinder and the valve are collectively accommodated in a narrow space, as compared with the case where the longitudinal direction of the cylinder and the valve extends along the longitudinal direction of the vehicle body.

[Effect] In order to make it possible to operate the gearshift lightly only by operating the servo valve, it is necessary to arrange a valve or cylinder on the lateral side of the gearshift case to reduce the vertical height of the gearshift case. In addition, the transmission is compactly configured by arranging the cylinders in a narrow space, and the body frame can be reduced in size.

The structure, operation and effect of the invention according to claim 7 are as follows.

[Structure] In the structure of the invention according to any one of claims 1 to 6, the suction pump and the discharge port of the hydraulic pump are aligned with the vehicle body, and the suction port of the hydraulic motor and the discharge port. The direction in which the mouths are lined up is different from the vehicle body direction.

[Operation] When the direction of the suction port and the discharge port with respect to the vehicle body are the same for both the hydraulic pump and the hydraulic motor, an oil passage connecting the pump-side suction port and the motor-side discharge port is formed. Even if one of the oil passages connecting the discharge port on the pump side and the suction port on the motor side becomes an extremely simple oil passage such as a straight oil passage, the other oil passage has many bends. It becomes a very complicated oil passage. In comparison with this case, the direction of the suction port and the discharge port with respect to the vehicle body is different between the pump side and the motor side, and any of the oil passages is not an extremely complicated shape but a simple shape that can be created relatively easily. A pump and a motor are connected while making an oil passage.

[Effect] A continuously variable transmission can be easily formed from the surface of the oil passage, and a device that can be advantageously used for getting on and off and driving from the surface of the vehicle body frame can be obtained at a low cost from the viewpoint of the transmission.

The structure, operation and effect of the invention according to claim 8 are as follows.

[Configuration] In the configuration of the invention according to claim 7, one of the suction port and the discharge port of the hydraulic pump and the hydraulic motor are arranged in the up-down direction of the vehicle body, and the other suction port and the discharge port are located below the vehicle body. Lined up in the direction.

[Operation] For example, by arranging the pump and the motor in the lateral direction of the vehicle body and forming the swash plate cam surface on the motor side on an inclined surface located on the rear side of the vehicle body so as to reach the lateral outside of the vehicle body, Even if the length can be made as small as possible, an oil path connecting the pump side suction port and the motor side discharge port, and an oil path connecting the pump side discharge port and the motor side suction port. The pump and the motor can be connected while making any of the oil passages relatively easy to make.

[Effect] An oil passage for connecting the pump and the motor is easily formed, and the continuously variable transmission is easily formed while forming the transmission case to be a compact one having a small vertical length, thereby reducing the cost. Advantageously obtained.

The structure, operation and effect of the invention according to claim 9 are as follows.

[Structure] The engine is mounted on one of the front and rear ends of the vehicle body.
In a work vehicle provided with a traveling transmission case in a state where a body frame is formed on the other end side, an engine output is transmitted to a transmission in the traveling transmission case via a hydrostatic continuously variable transmission. In addition, the hydrostatic stepless transmission forms the vehicle body frame by a transmission case provided to form an oil chamber accommodating a hydraulic pump and a hydraulic motor, and is formed in a direction in which a suction port and a discharge port of the hydraulic pump are arranged. The direction to the vehicle body is different from the direction to the vehicle body in the direction in which the suction port and the discharge port of the hydraulic motor are arranged.

[Operation] The continuously variable transmission is provided with its transmission case being a part of the vehicle body frame, so that the upper level in the vehicle body frame portion can be made as low as possible or the bottom level can be made as high as possible. While forming a body frame, the engine output is steplessly changed and transmitted for traveling.

As described above, any one of the oil path connecting the suction port on the pump side and the discharge port on the motor side and the oil path connecting the discharge port on the pump side and the suction port on the motor side are used. A pump and a motor are connected while using an oil passage having a simple shape that can be relatively easily formed.

[Effect] In the case where the vehicle can travel while shifting easily by the continuously variable transmission, the structure can be obtained simply by using the transmission case also as the body frame. In addition, the top height of the body frame is made as low as possible and the bottom height is made as high as possible, so that the driver deck or driver seat is low and it is easy to get on and off, and it is possible to drive stably, It is obtained in an advantageous state such as easy to run so that it is hard to touch the part. The continuously variable transmission can be made relatively easily from the viewpoint of the oil passage, and can be advantageously obtained economically.

The structure, operation and effect of the invention according to claim 10 are as follows.

[Structure] In the structure of the invention according to claim 9, one suction port and one discharge port of the hydraulic pump and the hydraulic motor are arranged in the up-down direction of the vehicle body, and the other suction port and discharge port are arranged in the lateral direction of the vehicle body. Lined up.

[Operation] For example, by arranging the pump and the motor in the lateral direction of the vehicle body and forming the swash plate cam surface on the motor side on the inclined surface located at the rear side of the vehicle body toward the lateral outside of the vehicle body, Even if the length can be made as small as possible, an oil path connecting the pump side suction port and the motor side discharge port, and an oil path connecting the pump side discharge port and the motor side suction port. The pump and the motor can be connected while making any of the oil passages relatively easy to make.

[Effect] An oil passage for connecting the pump and the motor is easily formed, and the continuously variable transmission is easily constructed while forming the transmission case to be a compact one having a small vertical length, so that it is economically advantageous. Advantageously obtained.

The structure, operation and effect of the invention according to claim 11 are as follows.

[Structure] The engine is mounted on one of the front and rear ends of the vehicle body.
In a work vehicle provided with a traveling transmission case in a state where a body frame is formed on the other end side, an engine output is transmitted to a transmission in the traveling transmission case via a hydrostatic continuously variable transmission. An operation unit that forms the vehicle body frame by a transmission case in which the hydrostatic continuously variable transmission is provided to form an oil chamber that houses a hydraulic pump and a hydraulic motor, and changes a swash plate angle of the hydraulic pump, A lateral side surface of the transmission case is arranged on an alligator.

[Operation] The above-described continuously variable transmission is provided with its transmission case being a part of the vehicle body frame, so that the upper level in the vehicle body frame portion can be made as low as possible or the bottom level can be made as high as possible. While forming the body frame, the engine output is steplessly shifted and transmitted for traveling. Further, the transmission can be obtained while the vertical height of the transmission case is reduced as compared with the case where the operation unit is disposed on the side surface of the transmission case and the transmission unit is disposed above or below the transmission case. .

[Effect] In the case where the vehicle can travel while shifting easily with the continuously variable transmission, the structure can be obtained simply by using the transmission case also as the body frame. Furthermore, the top height of the body frame is made as low as possible and the bottom height is made as high as possible from both sides, as the transmission case is also used as the body frame, and the vertical height of the transmission case can be made small, so that the driving section deck and driving Advantageous conditions can be obtained, such as lowering the seat, making it easier to get on and off, and driving stably, and the fact that the bottom of the body is so high that it is easy to run so that it does not easily come into contact with projections even on uneven terrain.

The structure, operation and effect of the invention according to claim 12 are as follows.

[Structure] In the structure of the invention according to claim 11, a servo cylinder and a servo valve for changing the swash plate angle of the hydraulic pump are provided in the operating section,
The longitudinal directions of the servo cylinder and the servo valve are aligned with the vertical direction of the vehicle body.

[Operation] When the servo valve is operated, the servo cylinder is driven to change the swash plate angle and change gears. In addition, the cylinder and the valve can be arranged on the lateral side of the transmission case so that the cylinder and the valve are collectively accommodated in a narrow space, as compared with the case where the longitudinal direction of the cylinder and the valve extends along the longitudinal direction of the vehicle body.

[Effect] In order to make it possible to operate the gearshift lightly only by operating the servo valve, it is necessary to arrange the valve or cylinder on the lateral side of the gearshift case to reduce the vertical height of the gearshift case. In addition, the transmission is compactly configured by arranging the cylinders in a narrow space, and the body frame can be reduced in size.

[0053]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a driving unit which is self-propelled by a pair of left and right drivable front wheels 1, 1 and rear wheels 2, 2 and has an engine E located at a front part of a vehicle body. A steering wheel 3 for swinging the front wheel 1 for steering operation, a driving unit having a driving seat 4 and the like, and a rear part of a vehicle body including a traveling transmission case 5 located at a rear part of the vehicle body,
The agricultural tractor is provided with a lift arm 6 for operatively connecting various working devices and a power take-out shaft 7 for transmitting power to the connected working devices. This tractor constitutes various types of work vehicles, such as forming a riding type tiller by connecting tillage devices.

As shown in FIGS. 1 and 2, the engine E, a front frame 8 extending forward from both sides of a lower portion of the engine E, and a flywheel housing 9 located at the rear of the engine E Main clutch housing 10 bolted to the rear of the main clutch housing 1
The vehicle body frame is formed by the transmission case 21 whose front end is connected to the rear end of the transmission case 0 and the traveling transmission case 5 whose front end is connected to the rear end of the transmission case 21. The traveling transmission case 5 is formed by a transmission case main body 5a whose front end is connected to the transmission case 21 and a differential case portion 5b whose front end is bolted to the rear end of the transmission case main body 5a. A front wheel differential mechanism 12 is provided in an intermediate portion of a front wheel transmission case 11 supported by the pair of left and right front frames 8, 8, and a rear wheel differential mechanism 13 is provided in the differential case portion 5b. Moving mechanism 12,
The transmission structure shown in FIG. 3 transmits the rotational output of the engine E to drive the front and rear wheels 1 and 2 so that the vehicle body can run on its own.

That is, the turning power of the flywheel 14 as an engine output member located inside the flywheel housing portion 9 is transmitted to the main clutch housing 1.
0, and a rotating shaft 16 whose front end is connected to the flywheel 14 by spline engagement.
The transmission mechanism 17 transmits the rotational power of the first output gear 17d of the transmission mechanism 17 to the input shaft 22 of the traveling main transmission 20 having the transmission case 21. It is. The rotational power of the output shaft 23 of the traveling main transmission 20 is transmitted to the input shaft 41 of the traveling auxiliary transmission 40 located inside the transmission case 5 via the gear mechanism 18. The rotational power of the output shaft 42 of the transmission 40 is transmitted to the rear wheel differential mechanism 13 via a rear wheel output gear 43 formed integrally with the rear end of the output shaft 42, and the rear end of the output shaft 42. The front wheel output gear 44 is rotatably mounted on the front wheel output gear 44, and the front wheel output gear 44 is transmitted to the front wheel differential mechanism 12 via the front wheel transmission shaft 19 whose rear end is interlocked via a gear mechanism. is there.

The traveling auxiliary transmission 40 includes a first shift gear 45 supported by a spline engagement with a transmission shaft 41a integrally rotatably connected to the input shaft 41 by a coupling, and integrally rotatably and slidably; A second shift gear 46 rotatably and slidably supported on the output shaft 42 by spline engagement; a gear 47 for supporting the first shift gear 45 so that the transmission shaft 41a is relatively rotatable; 42 is replaced with a gear 48 rotatably supported, and the second shift gear 46
And a gear 49 integrally formed with the transmission shaft 41a and an output shaft 42.
Is changed to the gear 48 that is supported by the motor, so that the rotational power of the input shaft 41 is changed in three stages and output from the output shaft 42. In other words, the rotational power from the traveling main transmission 20 is sub-shifted in three stages, and the front and rear wheels 1, 2,
To communicate.

The power take-out shaft 7 is rotatably supported at the rear of the traveling transmission case 5. The power take-off shaft 7 has a work mission 50 located inside the traveling mission case 5 as shown in FIGS. 3 and 4, a rear end portion of the main clutch housing 10, and a front surface of the rear end portion. And a case portion 10a which is bolted to the side, via each of the transmission mechanisms 17 located between the main clutch 15 and the transmission case 21 inside a transmission case portion 10b formed at the rear end of the main clutch housing 10. The engine E is configured to transmit power.

That is, as shown in FIG. 4, the transmission mechanism 17 is integrally formed on the rear end of the output cylinder shaft 15a of the main clutch 15 so as to be integrally rotatably connected to the output cylinder shaft 15a. A first input gear 17a, a first transmission gear 17b meshing with the first input gear 17a,
A second transmission gear 17c whose support shaft is integrally rotatably connected to the transmission gear 17b by spline engagement, the first output gear 17d meshing with the second transmission gear 17c, and the output cylinder shaft 15a are relatively rotatable. The second input gear 17 is integrally formed on the rear end of the rotary shaft 16 inserted therethrough so as to be integrally rotatable with the rotary shaft 16.
e, the second output gear 1 meshing with the second input gear 17e
7f. 1st output gear 1
7d is connected to the input shaft 22 of the traveling main transmission 20 so as to be integrally rotatable by spline engagement, and the second output gear 17f is formed integrally with the input shaft 51 of the work mission 50 by this input. It is connected to the shaft 51 so as to be integrally rotatable. As a result, the transmission mechanism 17 divides the rotational output of the engine E into two systems, a system having the main clutch 15 that can be connected and disconnected, and a system that has the rotating shaft 16 that cannot be connected and disconnected. The engine output is transmitted to the front and rear wheels 1 and 2 so that the engine output of the system that can be connected and disconnected is transmitted to the power take-out shaft 7 so that the engine output of the system that cannot be connected and disconnected is transmitted to the power take-out shaft 7. The input is branched to two systems, and is branched to the input shaft 22 as an input unit of the traveling main transmission 20 and the work mission 50 for transmission. The work mission 50 is a multi-plate type work clutch 52 which can be operated on the input side by supplying the pressure oil while using the input shaft 51 as an input shaft, and an output shaft 53 of the work clutch 52 is connected at one end to a output shaft 53 via a gear mechanism 54. The other end is constituted by a rotating shaft 55 which is connected to the power take-out shaft 7 by a coupling so as to be integrally rotatable. That is,
The rotational output of the engine E is branched by the transmission mechanism 17 from the traveling side and transmitted to the work mission 50 by the transmission mechanism 17 so that the speed does not change irrespective of the shift operation of the main transmission 20 and the auxiliary transmission 40 for traveling. The power is transmitted to the power take-out shaft 7 so that the clutch 52 can be connected and disconnected.

The traveling main transmission 20 is driven by a variable displacement hydraulic pump P driven by the input shaft 22 as a drive shaft, as shown in FIGS. And the fixed displacement hydraulic motor M having the output shaft 23 as an output shaft and the transmission case 2
1 is provided inside. As a result, the traveling main transmission 20 is located near the rear of the main clutch 15, and the engine output transmitted to the input shaft 22 is driven forward and backward by the hydraulic pump P and the hydraulic motor M. The output shaft 23 is converted into a force and the speed is continuously changed on both the forward side and the reverse side.
The transmission is transmitted to the traveling auxiliary transmission 40 from a hydrostatic continuously variable transmission. The details are configured as follows.

A transmission case body 21C made of cast iron having a flange portion 21a connected to the transmission case portion 10b of the main clutch housing 10 by bolts, a concave portion 24 opened to the rear of the vehicle body, and the like, and a rear end face of the transmission case body 21C. The transmission case 21 is formed by a cast iron port block 21P forming a flange portion connected to the transmission case main body 5a by bolts while closing the opening of the recessed portion 24 by bolt connection. And
The speed change case 21 is configured such that an oil chamber for housing the hydraulic pump P and the hydraulic motor M together with oil is formed by the recess 24, and the hydraulic pump P and the hydraulic motor M are housed in an oil reservoir so as to make it difficult to suck air. It is.

The hydraulic pump P and the hydraulic motor M are housed in the oil chamber 24 side by side in the lateral direction of the vehicle body. The hydraulic pump P is a cylinder block 2 having a plurality of plungers 25 slidably disposed around the input shaft 22.
6 such that the input shaft 22 is driven to rotate about the axis thereof, and that the ring-shaped swash plate 27 fitted to one end of the input shaft 22 swings with respect to the transmission case 21. It is configured as an axial plunger pump.
As the cylinder block 29 rotates, the hydraulic motor M rotates so that the cylinder block 29 including a plurality of plungers 28 slidably disposed around the output shaft 23 rotates integrally with the output shaft 23. The axial type plunger motor is configured so that the plunger 28 reciprocates and slides with respect to the cylinder block 29 by the action of a swash plate 30 provided inside the transmission case 21 by integral molding with the transmission case body 21C. The cam surface 30a of the swash plate 30 of the motor M is formed by a cam plate attached to the swash plate 30, and is formed to be inclined so as to be located on the rear side of the vehicle body toward the outside of the vehicle body. is there.

As shown in FIGS. 5 and 7, the hydraulic pump P
Of the hydraulic motor M are formed in such a manner that the two arc-shaped suction / discharge ports 31 are arranged side by side in the lateral direction of the vehicle body and extend over the inner surface of the port block 21P and the valve plate 32 fixed to the inner surface.
The three arc-shaped suction / discharge ports 33, 33 are
3 and a valve plate fixed to the inner surface of the port block 21P and arranged in the vehicle body vertical direction so that the direction of the body 3 in the parallel direction is different from the direction of the body in the parallel direction of the pump-side suction / discharge port 31. 34, one pump-side suction / discharge port 31 and one motor-side suction / discharge port 33 are connected by an oil passage 35a formed by a hole formed in the hydraulic port block 21P, and the other pump-side suction / discharge port is formed. 31 and the other suction / discharge port 33 on the motor side are connected by an oil passage 35b formed by a hole formed in the hydraulic port block 21P. That is, when the forward driving force is output, one of the two arc-shaped suction / discharge ports 31 of the hydraulic pump P is used.
Reference numeral 1 denotes a discharge port, and a suction / discharge port 33 of the hydraulic motor M connected to the pump-side suction / discharge port 31 serves as a suction port, and the other of the two arc-shaped suction / discharge ports 33, 33 of the hydraulic motor M. The suction / discharge port 33 is a discharge port.
When the suction / discharge port 31 of the hydraulic pump P connected to the hydraulic pump P becomes the suction port and outputs the reverse drive force,
The other one of the arc-shaped suction / discharge ports 31, 31
Is a discharge port, the suction / discharge port 33 of the hydraulic motor M connected to the pump-side suction / discharge port 31 serves as a suction port, and one of the two arc-shaped suction / discharge ports 33, 33 of the hydraulic motor M. The port 33 is a discharge port, and the suction and discharge port 31 of the hydraulic pump P connected to the motor-side suction and discharge port 33 becomes a suction port.
In any case, the pressure oil discharged from the hydraulic pump P is
The oil supplied to the hydraulic motor M via 5a or 35b and discharged from the hydraulic motor M returns to the hydraulic pump P via the oil passage 35b or 35a.

As shown in FIG. 5, the side surface of the transmission case 21 where the hydraulic pump P is located is provided in the mounting hole of the cylinder mounting portion 21b formed by integral molding with the transmission case body 21C. A hydraulic servo cylinder 61 incorporated in an assembling posture in which the cylinder longitudinal direction is along the vehicle body vertical direction, and a hydraulic servo cylinder mounted in an assembling posture in which the valve longitudinal direction is along the vehicle body vertical direction on the outer surface side of the cylinder assembling portion 21b. The valve 62 constitutes an operation unit 60 for changing the swash plate angle of the hydraulic pump P. That is, FIG.
As shown in FIG. 9, the operation lever 63 of the servo valve 62 is supported by a valve case 65 via a rotation shaft 64. When the operation lever 63 is swung about the axis of the rotation support shaft 64, the rotation support shaft 64 is
The operation part 66 extending from the rotation support shaft 64 swings around the axis of the rotation support shaft 64 inside the valve case 65, and the operation part 66 is connected to the valve operation link 6.
The swing operation is performed using the valve operating link 67 via the connecting pin 66a engaged with one end of the servo cylinder 41 with the other end engaged with the servo cylinder 41 as a swing fulcrum. Then, the connecting pin 67a connecting the intermediate portion of the valve operation link 67 to the valve spool 68 is moved from the neutral position to the connecting pin 6a.
6a moves in the same direction as the moving direction of the valve spool 6a.
5 is switched from the neutral position to the drive side, the servo cylinder 61 is driven by pressure oil, and the swash plate is protruded from the servo cylinder 61 by the operation pin portion 61a engaged with the swash plate 27 as shown in FIG. 27 to control lever 6
On the forward side or the reverse side corresponding to the operation direction 3, the swing operation is performed on the speed increasing side or the decelerating side. The servo cylinder 61 swings the swash plate 27 while swinging the valve operation link 67 with the connection pin 66 a as a swing fulcrum, and the angle at which the swing of the swash plate 27 is changed corresponds to the operation stroke of the operation lever 63. When the angle reaches a proportional angle, the connecting pin 67a returns to the neutral position, and the valve spool 68 is returned to the neutral position and operated. Thus, when the angle of the swash plate 27 changes in a direction corresponding to the operation direction of the operation lever 63 by an angle proportional to the operation stroke of the operation lever 63, the servo valve 62 automatically returns to the neutral state, and the servo cylinder 61 Stops, and the swing operation of the swash plate 27 is stopped.

The continuously variable transmission 20 is configured to perform a shift operation by a shift operation structure including a single shift pedal 71 supported by a deck 70 of the driving section. This speed change operation structure is configured as shown in FIG.

That is, as shown in FIG. 15, the speed change pedal 71 has a forward operating portion 71a at the front end and a reverse operating portion 71b at the rear end connected to each other.
The forward operating portion 71a is formed as a single-part pedal formed so that the forward operating portion 71a is deviated laterally outward from the reverse operating portion 71b so that the backward operating portion 71b is easily depressed with the heel and the backward operating portion 71b is easily depressed. It is. Further, the transmission is located at a higher level than the continuously variable transmission 20 and the continuously variable transmission 20 is, when viewed from the side of the vehicle body, the swing fulcrum 71 d of the shift pedal 71.
The forward operation portion 71a of the speed change pedal 71 and the rear end side of the continuously variable transmission 20 are disposed on the upper surface side of the driving section deck 70 in a transmission arrangement in which the forward end portion of the transmission pedal 71 and the rear end side of the continuously variable transmission 20 overlap in the vehicle longitudinal direction. Bracket 7 supported by driving unit deck 70
2 is supported so as to swing around a shaft center 71d as the swing supporting point.

The support member 73, which is connected to the side wall of the body frame by bolts, is rotatably supported around the axis P1 so that the body frame is rotatably supported around the axis P1 oriented laterally to the body. Interlocking member 74, which is configured to be connected, and four connecting points 74a to 74d provided in an arrangement in which the interlocking member 74 is dispersed around the axis P1.
By connecting a first connection point 74a of the one cam follower portion 74e located on the vehicle body front side with respect to the shaft center P1 to the output portion 71c of the shift pedal 71, the interlocking member 74 and the shift pedal 71 are linked. In addition, the first interlocking rod 75 and the interlocking member 74, each of which is a rod member passing through the through hole in a posture substantially perpendicular to the driving unit deck 71 in a posture in which the longitudinal direction is along the vehicle body vertical direction, The pivot shaft P1 and the second connection point 74b located at a lower level than the first connection point 74a among the four connection points 74a to 74d are connected to the operation lever 63 of the servo valve 62 to be linked. A second interlocking rod 76, which is a rod member that has an assembly posture in which the member 74 and the operation lever 63 are interlocked and whose longitudinal direction is substantially along the vehicle longitudinal direction. By respectively, are constructed a mechanical interlocking mechanism 77 for interlocking connecting the shift pedal 71 to the servo valve 62 of the operation unit 60.

The cam member 78 having a cam portion 78a, which is a roller acting on the cam follower portion 74e located on the vehicle rear side with respect to the pivot axis P1 of the interlocking member 74, is attached to the middle portion of the support member 73. By supporting the interlocking member 74 and the interlocking member 74 at a time by assembling the vehicle body frame, the supporting member 73 is supported so as to be swingable around the axis P2 in the lateral direction of the vehicle body. The cam member 78 is connected to the interlocking member 74 by the spring 79 attached to the
And the cam portion 78a is pressed against the cam follower portion 74e of the interlocking member 74. That is, the cam portion 78a of the cam member 78 is
As shown in FIG. 10, the elastic restoring force is applied to the cam follower portion 74e in the shape of a letter as shown in FIG. 10 to give a swing resistance to the interlocking member 74 and to attach the interlocking member 74 so that the shift pedal 71 and the operation lever 63 are in the neutral position. Energize. As a result, the cam member 78 gives the transmission pedal 71 and the operation lever 63 an operation resistance and a force for automatically restoring the neutral position.

The first interlocking rod 75 with respect to the interlocking member 74
And the tube side of the damper 80 arranged on the side opposite to the side where the second interlocking rod 76 is located at a higher level than the swing axis P1 of the four connection points 74a to 74d of the interlocking member 74. A damper holder 81, which is rotatably connected to a fourth connection point 74d located thereat and holds the rod side of the damper 80, is rotatably connected to a support member 82 fixed to the vehicle body frame. That is, even if the vibration is transmitted from the swash plate 27 to the operation lever 63 and the shift pedal 71, the vibration of the shift pedal 71 and the operation lever 63 is attenuated by the damper 80 acting on the interlocking member 74. Further, an operating resistance is applied to the shift pedal 71 via the interlocking member 74 and the first interlocking rod 75 to prevent the shift pedal 71 from being quickly operated.

The interlocking member 74 has a boss portion connected to the support member 73 and a first link member forming a second connection point 74b, a third connection point 74c, and a fourth connection point 74d. A second link member rotatably connected to the boss portion of the member and forming a first connection point 74a; a plate member connected rotatably to the boss portion of the first link member and forming a cam follower portion 74e; 3
It is formed of three members.

That is, the forward operation portion 71 of the speed change pedal 71
When a is depressed from the neutral position, the operating force is transmitted to the operating lever 63 by the interlocking mechanism 77, so that the operating lever 63 swings forward and the servo valve 62 switches to the forward side, and the continuously variable transmission. 20 switches from the neutral state to the forward side. As a result, the vehicle body moves forward. When the forward operation part 71a is further depressed, the swinging sloke of the operation lever 63 toward the front side of the vehicle body increases, the swash plate change angle by the servo cylinder 61 increases, and the continuously variable transmission 20 operates at high speed. Shift to the side. As a result, the vehicle forward speed increases. Speed change pedal 71
When the reverse operation portion 71b is depressed from the neutral position, the operation force is transmitted to the operation lever 63 by the interlocking mechanism 77.
Operating lever 63 swings rearward of the vehicle body, the servo valve 62 switches to the reverse side, and the continuously variable transmission 20 switches from the neutral state to the reverse side. As a result, the vehicle body runs backward. When the reverse operation portion 71b is further depressed, the swinging sloke of the operation lever 63 toward the rear of the vehicle body increases, the swash plate change angle by the servo cylinder 61 increases, and the continuously variable transmission 20 operates at high speed. Shift to the side. As a result, the vehicle reverse speed increases. In any case of forward and backward travel, when the stepping operation on the shift pedal 71 is released, both the shift pedal 71 and the operation lever 63 automatically move toward the neutral position due to the neutral restoring action of the cam member 78, Continuously variable transmission 20
Shifts to the deceleration side. As a result, the vehicle running speed decreases. Finally, both the speed change pedal 71 and the operation lever 63 return to the neutral position, and the continuously variable transmission 20 returns to the neutral state. This stops the vehicle running. At this time, both the operation lever 63 and the speed change pedal 71 are stably held at the neutral position due to the damping action by the damper 80 and the positioning action by the cam member 78.

As shown in FIG. 11, the driving unit deck 70
Is a sheet metal deck body 70 supported by the body frame.
a, and a cushion rubber sheet 70b laid on the upper surface side of the deck body 70a. The deck main body 70a is attached to the vehicle body frame by a mounting structure shown in FIG. That is, the mounting portion 70c located on the back surface side of the deck main body 70a is placed via a cushion rubber 84 on a deck support member 83 connected to a lateral side surface of the transmission case main body 5a or the like of the vehicle body frame. It is prevented from coming off by a mounting bolt 85 penetrating the rubber 84. As a result, the driving unit deck 70 is provided with the cushion rubber 84 so that vibration is hardly transmitted from the vehicle body frame.
And is supported by the body frame.

As shown in FIG. 10, the pivot shaft P1 of the four connection points 74a to 74d of the interlocking member 74
Third connection point 74 located at a lower level than the rear side of the vehicle body
c, a speed holding member 87 connected via a rod 86,
It is disposed on the opposite side of the interlocking member 74 from the side where the first interlocking rod 75 and the second interlocking rod 76 are located, and is swingably supported on the upper part of the transmission case main body 5a via a rotary support shaft 88. 13, a lock member 89 for locking and releasing the lock of the speed holding member 87 by the side of the transmission case main body 5a opposite to the side where the speed holding member 87 is located. A cruise device for traveling with the continuously variable transmission 20 fixed at a desired set speed state is provided by providing the same.

That is, as shown in FIGS. 12 and 13, the transmission case main body 5 of the rotary support shaft 88 is provided.
A lock arm 90 is rotatably connected to a shaft end protruding toward the lateral side where the lock member 89 of FIG. The lock member 89 is formed of a member having a saw-toothed uneven portion 89a acting on the lock arm 90, and rotates around the axis P3 to a support member 91 to which the lateral side surface of the transmission case main body 5a is bolted to the alligator. At the lock release position where it comes into contact with the stopper pin 92 on the back side of the concave and convex portion 89a. An operation cable 95, which can be pushed and pulled and transmitted through a swing link 95a, is connected to the free end of the lock device 90 via a swing link 95a, and is slidably attached to a panel portion located below the steering handle 3 of the driving unit. It is.

That is, the operating tool 95 is pulled out from the panel portion toward the driver's seat 4 while setting the desired speed state in which the continuously variable transmission 20 is fixed by depressing the shift pedal 71 forward. By operating, the lock member 89 is swung toward the lock arm 90 against the release spring 93 so that the concave and convex portion 89a is engaged with the locking piece portion 90a located at the tip end of the lock arm 90. Then, the lock member 89 is maintained in a state of being engaged with the lock arm 90 against the release spring 93 by the action of the shape of the uneven portion 89 a and the like, and the speed holding member is fixed via the lock arm 90 and the rotation support shaft 88. The lock 87 is locked at a position corresponding to the set speed of the continuously variable transmission 20 against the neutral restoring force of the cam member 78. Thereby, the speed holding member 87 is connected to the rod 86,
The operation lever 63 of the operation unit 60 is fixed to the set operation position set by the speed change pedal 71 via the interlocking member 74 and the second interlocking rod 76 against the neutral restoring force. Therefore,
The continuously variable transmission 20 can be fixed at a desired speed state set by the shift pedal 71. From this state, the operating tool 95
Is pushed toward the panel portion to release the engagement between the lock member 89 and the lock arm 90.
Is returned to the unlock position by the release spring 93 to release the lock of the speed holding member 87 and release the fixed speed of the continuously variable transmission 20.

As shown in FIG. 13, the operating cable 9 having one end connected to the free end of the lock member 89 opposite to the side where the concave and convex portions 89a are located with respect to the pivot axis P3.
6. The lock member 89 is connected to both brake pedals 97 via an interlocking regulation mechanism 100 located between the other end of the operation cable 96 and the pair of left and right brake pedals 97a and 97b.
a, 97b. The interlocking regulation mechanism 100
Is configured as shown in FIG. 13 and FIG. That is, the left operating arm 101a and the right brake pedal 9 that extend from the boss portion of the left brake pedal 97a so as to be rotatable together.
7b extending right from the boss portion of the right operation arm 101 and being longer than the left operation arm 101a.
b, a lock operating link 102 positioned between the left and right operating arms 101a and 101b and connected to the operating cable 96, one end of which is rotatably connected to the lock operating link 102, and the other end of which is the left operating Arm 1
Left operating link 10 rotatably connected to the free end side of 01a
3a, a right operation link 103b rotatably connected at one end to the lock operating link 102 and rotatably connected to a free end of the right operation arm 101b at the other end. That is, when only the left brake pedal 97a is depressed as shown in FIG. 16A, the left operation arm 101a swings together with the pedal 97a, but the right operation arm 101b does not swing, so that the left operation link 103a Is the lock operation link 102
The swing operation is performed only by swinging the connection point with the swing support point, and the moving operation of the lock operation link 102 is not performed. Thus, the lock operation link 102 does not pull the operation cable 96. When only the right brake pedal 97b is depressed as shown in FIG.
01b swings together with the pedal 97b, but the left operating arm 101a does not swing.
“b” only swings using the connection point with the lock operating link 102 as a swing fulcrum, and does not move the lock operating link 102. Thereby, the lock operation link 102
Does not pull the operation cable 96. On the other hand, as shown in FIG.
a and the right brake pedal 97b are depressed together, the left operation arm 101a and the right operation arm 101b swing together, and the left operation link 103a and the right operation link 10
3b, the lock operation link 102 is moved in the moving direction of the operation arms 101a and 101b. Accordingly, the lock operation link 102 pulls the operation cable 96, and when the lock 89 is at the lock position, the lock operation is switched from the lock position to the unlock position.

In other words, when the vehicle is running with the continuously variable transmission 20 fixed at the set speed, an operation of applying a brake to only one of the left and right rear wheels 2 is performed. The fixed speed of the continuously variable transmission 20 is not released so that the small-speed turning traveling can be performed as it is. When the brake is applied to both the left and right rear wheels 2, 2, the continuously variable transmission 2
The fixed speed of the continuously variable transmission 20 is automatically released so that the switching operation to the stop state of 0 can be performed.

As shown in FIGS. 5 to 7, each of the three through holes 36 to 38 provided in the continuously variable transmission 20 has a pipe mounted over the front wall portion of the transmission case body 21C and the port block 21P. It is formed by the material. The first through hole 36 located at the highest level among the three through holes 36 to 38 is provided with the work mission 50.
Is inserted through the input shaft 51. The second through hole 37 located at the intermediate level is provided in the transmission case portion 10b.
Are connected to each other so that lubricating oil flows through the inside of the transmission case 5 and the inside of the traveling transmission case 5. Third through hole 38 located at the lowest level
Is for the front wheel transmission shaft 19 to pass through.

[Alternative Embodiment] FIG. 17 shows a hydrostatic continuously variable transmission that constitutes a traveling main transmission 20 according to another embodiment.
Is formed simultaneously with the clutch housing 10 when the main clutch housing 10 is manufactured, so that the main clutch housing 10 is integrally formed as an integral part thereof.

[Brief description of the drawings]

Fig. 1 Side view of the whole agricultural tractor

FIG. 2 is a side view of a vehicle body frame.

FIG. 3 is a schematic diagram of a transmission system.

FIG. 4 is a sectional view of an arrangement portion of a main clutch and a transmission mechanism.

FIG. 5 is a sectional view of a continuously variable transmission for traveling.

FIG. 6 is a cross-sectional view of a portion where a hydraulic pump is provided in the continuously variable transmission for traveling.

FIG. 7 is a sectional view of a drive oil passage for a continuously variable transmission.

FIG. 8 is a sectional view of a servo valve operating unit.

FIG. 9 is a sectional view of a servo valve.

FIG. 10 is a side view of an interlocking mechanism between the speed change pedal and the continuously variable transmission.

FIG. 11 is a sectional view of an operation unit deck.

FIG. 12 is a sectional view of an arrangement portion of a speed holding member.

FIG. 13 is a side view of the cruise device.

FIG. 14 is a plan view of an arrangement of a brake pedal.

FIG. 15 is a plan view of a speed change pedal.

FIG. 16 is a diagram illustrating the operation of the interlocking regulation mechanism.

FIG. 17 is a side view of a vehicle body frame including another embodiment.

[Explanation of symbols]

 Reference Signs List 5 transmission transmission case 10 main clutch housing 21 transmission case 24 oil chamber 31 pump suction port, discharge port 33 motor suction port, discharge port 40 mission 60 operation unit 61 servo cylinder 62 servo valve E engine P hydraulic pump M Hydraulic motor

Claims (12)

[Claims] 1. A work vehicle equipped with an engine at one of front and rear ends of a vehicle body and a traveling transmission case at a vehicle body frame at the other end, wherein the engine output is shifted by a hydraulic pump and a hydraulic motor. A hydrostatic continuously variable transmission for transmitting to a transmission in the traveling transmission case is disposed between the engine and the traveling transmission case, and the hydrostatic continuously variable transmission controls a hydraulic pump and a hydraulic motor. A work vehicle in which the vehicle body frame is formed by a shift case provided to form an oil chamber to house. 2. The work vehicle according to claim 1, wherein the transmission case is connected to a main clutch housing connected to a rear portion of the engine and the traveling transmission case. 3. The work vehicle according to claim 2, wherein the transmission case is formed integrally with the main clutch housing. 4. The work vehicle according to claim 1, wherein the hydraulic pump and the hydraulic motor are arranged side by side in the vehicle body in the speed change case. 5. The work vehicle according to claim 1, wherein an operation unit for changing a swash plate angle of the hydraulic pump is arranged on a side surface of the transmission case. 6. The servo unit and a servo valve for changing the swash plate angle of the hydraulic pump are provided in the operation unit, and the longitudinal directions of the servo cylinder and the servo valve are aligned with the vertical direction of the vehicle body. Work car. 7. The hydraulic pump according to claim 1, wherein the direction of the suction port and the discharge port of the hydraulic motor is different from the direction of the vehicle body, and the direction of the suction port and the discharge port of the hydraulic motor is different from the direction of the vehicle body. The work vehicle according to any one of claims 6 to 6. 8. The suction port and the discharge port of one of the hydraulic pump and the hydraulic motor are arranged in the vertical direction of the vehicle body, and the other suction port and the discharge port are arranged in the horizontal lower direction of the vehicle body.
The working vehicle described. 9. A work vehicle provided with an engine at one of the front and rear ends of a vehicle body and a traveling transmission case formed at a vehicle body frame at the other end, wherein the engine output is transmitted via a hydrostatic continuously variable transmission. The vehicle body frame is formed by a transmission case that is configured to transmit to a transmission in the traveling transmission case, and the hydrostatic stepless transmission is provided with an oil chamber that houses a hydraulic pump and a hydraulic motor. A work vehicle in which the direction of the body of the hydraulic pump in which the suction port and the discharge port are arranged is different from the direction of the body of the hydraulic motor in which the suction port and the discharge port are arranged. 10. A suction port and a discharge port of one of the hydraulic pump and the hydraulic motor are arranged vertically in the vehicle body, and the other suction port and a discharge port are arranged in a lateral direction of the vehicle body.
The working vehicle described. 11. A work vehicle equipped with an engine at one of front and rear ends of a vehicle body and a traveling transmission case at a vehicle body frame at the other end, wherein the engine output is transmitted via a hydrostatic continuously variable transmission. The vehicle body frame is formed by a transmission case that is configured to transmit to a transmission in the traveling transmission case, and the hydrostatic stepless transmission is provided with an oil chamber that houses a hydraulic pump and a hydraulic motor. A work vehicle in which an operation unit for changing a swash plate angle of the hydraulic pump is arranged on a side surface of the transmission case. 12. A servo cylinder and a servo valve for changing the swash plate angle of the hydraulic pump are provided in the operation unit, and the longitudinal directions of the servo cylinder and the servo valve are aligned with the vertical direction of the vehicle body. Work car.