JP2003227561A - Transmission for working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simply structured transmission which effectively prevents high-temperature return oil fed from an HST or hydraulic device to a case from being circulated and supplied to the HST or hydraulic device, keeping the high temperature, in the transmission having a mission case reserving oil. <P>SOLUTION: The mission case is partitioned into a front chamber, an intermediate chamber, and a rear chamber communicating oil to each other by a front support wall and a rear support wall sequentially disposed in the longitudinal direction of the vehicle. The return oils from the HST and hydraulic device are made to flow into the front chamber and the rear chamber, respectively, and a hydraulic pump sucks the oil from the intermediate chamber. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission in a work vehicle provided with a work device such as a cultivator and a mower device.

[0002]

2. Description of the Related Art Generally, an HST and a transmission having a multi-stage transmission are inserted in series in a travel system transmission route from an engine to driving wheels in order to widen a shift range. When the working device mounted on the traveling machine body is reciprocally movable, a hydraulic device such as a hydraulic lift device that reciprocates the working device is provided together with the PTO shaft for the working device.

Generally, the transmission case of the transmission can lubricate mechanical elements such as the multi-stage transmission accommodated in the case, and can also store oil serving as a pressure oil supply source to the HST and the hydraulic device. Is configured.

More specifically, the oil stored in the mission case is sucked by an attached hydraulic pump and supplied to the HST and the hydraulic device at a predetermined hydraulic pressure.
Then, the return oil from the HST and the hydraulic device is returned to the inside of the mission case.

By the way, the return oil from the HST and the hydraulic device has a high viscosity due to high temperature. Therefore, if the low-viscosity return oil is simply circulated, the hydraulic pump, H
The amount of oil leakage increases in each part of the ST and the hydraulic system, and as a result, the pump efficiency of the hydraulic pump, the HST efficiency, and / or the hydraulic system efficiency deteriorate.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and in a transmission having a mission case configured to be able to store oil, a HST or a hydraulic device is connected to the case. An object of the present invention is to provide a transmission having a simple structure that can effectively prevent the high-temperature return oil from being circulated and supplied to the HST and the hydraulic device at a high temperature.

[0007]

In order to achieve the above-mentioned object, the present invention is a transmission for a working vehicle provided with a working device that is moved up and down by a hydraulic device, and is configured to store oil. A transmission case, a PTO system input shaft supported by the case, a PTO system input shaft operatively receiving a driving force from an engine and operatively connected to a hydraulic pump, and a case supported by the case. Driving system input shaft, the driving force from the engine is HS
A traveling system input shaft operatively received via T and operatively connected to a drive axle, wherein the hydraulic pump is H
The case is configured to supply pressure oil to the ST and the hydraulic device, and the case is a front chamber, a middle chamber, and a rear chamber that are partitioned by a front support wall and a rear support wall that are sequentially provided along the vehicle front-rear direction. And has a front chamber, a middle chamber, and a rear chamber that allow oil to flow through each other, and return oil from the HST and the hydraulic device is introduced into the front chamber and the rear chamber, respectively, and The hydraulic pump provides a work vehicle transmission configured to suck oil from the inner chamber.

Preferably, the front chamber houses a PTO clutch for turning on / off the power transmission from the PTO system input shaft downstream of the power transmission of the hydraulic pump, and the rear chamber for driving the PTO shaft. While housing the drive train, the front chamber and the rear chamber are communicated with each other via a relay chamber that houses a PTO transmission shaft that connects the PTO clutch and the drive train. More preferably, it further comprises a brake shaft arranged at a front stage in the transmission direction of the drive axle, and a brake mechanism for applying a braking force to the brake shaft, the brake shaft and the brake mechanism being the relay chamber. The relay chamber is configured so that oil can flow in from the front chamber and can escape into the middle chamber. More preferably, the rear chamber is provided with an inner wall that temporarily receives return oil from the hydraulic device.

More preferably, it further comprises a multi-stage transmission device for shifting the driving force input to the traveling system input shaft in multiple stages and operatively transmitting it to the drive axle. The multi-stage transmission may be housed in the front chamber. The input end of the drive axle may be housed in the interior chamber.

The present invention further provides a hydraulic clutch mechanism that selectively engages / disengages the PTO system transmission path, and a braking force applied to a rotating member forming the PTO system transmission path when the power is shut off by the hydraulic clutch mechanism. In a transmission provided with a PTO system transmission mechanism having a hydraulic brake mechanism for adding the above and a transmission case accommodating the PTO system transmission mechanism, the following transmission is provided for the purpose of facilitating the manufacture of the transmission case. That is, the present invention is directed to a mission case having a main body portion having an opening at least on one side in the vehicle width direction and a side lid portion closing the opening of the main body portion, and a transmission case supported by the case and operatively connected to an engine. PTO input shaft, and a P supported by the case so that it can be output to the outside of the case.
A work vehicle transmission having a TO shaft and a PTO system transmission mechanism forming a power transmission path from the PTO system input shaft to the PTO shaft, wherein the PTO system transmission mechanism is provided from the PTO system input shaft to the PTO system transmission mechanism. A hydraulic clutch mechanism that can selectively cut off the power transmission path to the PTO shaft, and the PTO when the power transmission path of the hydraulic clutch mechanism is cut off.
The hydraulic brake mechanism includes a clutch device having a hydraulic brake mechanism that applies a braking force to the rotating member of the system transmission mechanism. The hydraulic brake mechanism has a base end portion slidably housed in a cylinder chamber and a tip end portion. The PTO system transmission mechanism includes a pushing member configured to engage / disengage with a rotating member of the PTO system transmission mechanism, and controls the pressure oil supply to the cylinder chamber to cause the pushing member to move to the PTO system transmission mechanism. A braking force is selectively applied to and released from the cylinder chamber, and the cylinder chamber provides a transmission for a working vehicle formed on a side lid portion of the mission case.

Preferably, the hydraulic clutch mechanism and the hydraulic brake mechanism are configured to be operated by hydraulic oil supplied from a common hydraulic source. The side lid portion includes a hydraulic oil control member that controls the supply of hydraulic oil to the hydraulic clutch mechanism and the hydraulic brake mechanism, and a pressure oil distributor that distributes hydraulic oil to each of the hydraulic clutch mechanism and the hydraulic brake mechanism. It is provided. More preferably, the hydraulic oil control member and the pressure oil distributor are detachably attached to the outside and the inside of the side cover, respectively.

[0012]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a side view schematically showing a vehicle 100 to which this embodiment is applied.

As shown in FIG. 1, the vehicle 100 includes a bucket device 11 at the front, at the lower center and at the rear.
1, working devices such as a mower device 112 and a cultivator (not shown) can be attached. In the following description, a working device such as the mower device 112 arranged immediately in front of the transmission 30 is referred to as a first working device,
A work device such as a cultivator arranged behind the transmission is referred to as a second work device.

In the vehicle 100, an engine 10a, an HST 20, and a transmission 30 are sequentially arranged on a chassis 101 along a longitudinal direction of the vehicle, and a seat 102 is arranged above the transmission 30. More specifically, the power output from the engine 10a is transmitted from an elastic joint (not shown) attached to the center of rotation of the flywheel 10b through a transmission shaft 10c having universal joints at both ends and inclined rearward and downward. HST20
Is introduced into the input shaft 21a of.

Reference numeral 10d in FIG. 1 is a cooling fan installed on the universal joint on the downstream side in the transmission direction of the transmission shaft 10c, and the wind generated by the cooling fan 10d is the HST 20 or the mission. The oil that is stored inside the case 60 and circulates in each part is indirectly cooled, and the line filter 68 and the auxiliary pump 420, which will be described later, are also cooled. Further, above the front portion of the chassis 101, the engine 10a
A radiator and a fuel tank related to the engine 10a are mounted, and these parts are covered with a bonnet.

A front axle case 10e is mounted below the front portion of the chassis 101 so as to extend in the chassis width direction. More specifically, the left and right end portions of the front axle case 10e are vertically swingably suspended via a center pin arranged along the front-rear direction at approximately the center of the chassis width direction. The front axle is projected outward from the left and right ends of the front axle case 10e, and the front wheels are mounted on the front axle.

Further, reference numeral 10f in FIG. 1 designates a front wheel driving force output shaft 53a protruding from the front surface of a mission case 60, which will be described in detail later, and the front axle case 10e.
It is a transmission shaft that connects with the input shaft of. The transmission shaft 10f
The rear end of the front wheel power take-off shaft 53 via a universal joint.
a substantially horizontal first portion connected to a and a rear end portion connected to a front end portion of the first portion via a universal joint and a front end portion connected to an input shaft of the front axle case via the universal joint. And a second portion inclined downward to the front. In addition,
Via the front wheel power transmission mechanism, the front wheels are the rear wheels 18
It is driven by rotational power synchronized with zero. The sheet 102
Is mounted on a mount stay 10g that is laid across the rear upper surface of the mission case 60 and the front surface of a valve unit 410 described later.

FIG. 2 shows the HS in the transmission structure of the vehicle.
The partial disassembled perspective view of T20 and the transmission 30 part is shown. 3 and 4 show the HST2, respectively.
0 and the transmission 30 are shown in a longitudinal side view and a partially transverse plan view. Further, in FIG. 5, VV in FIG.
A line sectional view is shown.

As shown in FIGS. 2 and 3, the HST 20 is a hydraulic pump main body 21 having a pump shaft 21a operatively connected to the engine 10 and arranged along the longitudinal direction of the vehicle, and the pump. A hydraulic motor main body 22 having a motor shaft 22a arranged below the shaft 21a in parallel with the pump shaft 21a;
And a center section 23 supporting the hydraulic motor main body 22, the hydraulic pump main body 21 and the hydraulic motor main body 2
And an HST casing 24 connected to the center section 23 so as to surround the center section 23.

The HST 20 includes the hydraulic pump main body 21.
At least one of the hydraulic motor main body 22 and the hydraulic motor main body 22 is of a variable displacement type capable of varying the suction / discharge amount based on an operation from the outside.
The number of rotations of can be changed. For more information,
The HST 20 has an output control arm 25 for controlling the rotation output of the motor shaft 22a. The output control arm 25a is operatively connected to a forward / backward traveling pedal (not shown) provided on a right step (not shown) installed on the chassis 101.

As shown in FIG. 3, the rear ends of the pump shaft 21a and the motor shaft 22a pass through the center section 23, respectively, and are input shafts (PTO system input shafts) for a working device of a transmission to be described later. 31 and a vehicle traveling input shaft (traveling system input shaft) 34.

6 and 7 are a front view and a rear view, respectively, of a mission case 60 to be described later with a front lid portion 62 removed and a rear lid portion 63 removed. Further, FIG. 8 shows a development view of the traveling system drive train taken along the line VIII-VIII in FIG. Further, FIG. 9 is a development view of the drive train (PTO system) of the working device of the transmission 30 taken along the line IX-IX in FIG. 7.

As shown in FIGS. 3 to 9, the transmission 30 is a work device driving input shaft (PTO system input) which is disposed concentrically with the pump shaft 21a and is connected so as not to rotate relative to the axis. Shaft) 31, a rear PTO shaft 32 for the second working device, and a mid PT for the first working device
O shaft 33, the PTO system input shaft 31, and the rear PTO shaft 3
2 and the mid PTO shaft 33, a PTO system transmission mechanism 40, and a traveling system input shaft 3 that is arranged concentrically with the motor shaft 22a and is connected so as not to rotate relative to the axis.
4, a traveling system transmission mechanism 50 that connects the traveling system input shaft 34 and a ring gear 151 of a differential gear device 150 that differentially drives a pair of driving wheels, and a mission case 60 that supports the above-mentioned members. Is equipped with.

As shown in FIG. 3, FIG. 5, FIG. 8 and FIG. 9, the mission case 60 has a main body portion 61 whose front and rear sides in the vehicle longitudinal direction and one side in the vehicle width direction are opened.
A front lid portion 62 and a rear lid portion 63 that close the front opening and the rear opening of the body portion 61, respectively, and a side lid portion 64 that closes the side opening of the body portion 61. Is configured to be stored.

At the rear of the mission case 60,
As shown in FIG. 1, a work implement mounting hitch 480 that supports the second work device in a vertically movable manner is provided. The work implement mounting hitch 480 includes left and right lower links 482 pivotally supported by left and right mounting stays 481 mounted on the rear of the mission case 60, and a lift arm 40 whose front end is described later.
6, a lift rod 483 swingably connected to a free end portion of the rear end portion 6 and a rear end portion swingably connected to the lower link 482; It is a three-point link type hitch with a top link 485 pivotally supported by 484 (see FIGS. 2 and 3).

As shown in FIG. 3, the main body 61 has front support walls 6 on the front and rear sides in the longitudinal direction of the vehicle.
It has a la and a rear support wall 61b. The front support wall 61a and the rear support wall 61b, which are sequentially provided along the vehicle front-rear direction, partition the internal space of the main body 61 into a front chamber C1, a middle chamber C2, and a rear chamber C3. The front chamber C1, the middle chamber C
2 and the rear chamber C3 are configured so that oil can flow through each other. In the present embodiment, a relay chamber C4 is provided above the middle chamber C2, and the front chamber C1, the middle chamber C2, the rear chamber C3, and the relay chamber C4 are allowed to flow oil with each other. That is, an oil communication opening 61x that connects the front chamber C1 and the relay chamber C4 is provided at a substantially central position in the vertical direction of the front support wall 61a. The relay room C4 has a rear support wall 61.
The rear chamber C3 is opened through the opening provided in b.
Further, an oil communication opening 61y that communicates the middle chamber C2 and the rear chamber C3 is provided at a lower position in the vertical direction of the rear support wall 61b (see FIGS. 3, 7 and 9). The inner chamber C2
A storage space for a power transmission mechanism to the drive axle is secured below the. Specifically, the input end (inner end) of the drive axle is supported below the inner chamber C2. In the present embodiment, the differential gear device is provided as a power transmission mechanism to the drive axle, and therefore, the differential gear device accommodation space is secured below the inner chamber C2. More specifically, as shown in FIG. 5, the storage space is displaced to one side in the width direction of the mission case with reference to the traveling system input shaft 34, which will be described in detail later.

In FIG. 6, symbol OL indicates an oil level when a later-described oil filling plug 62d is opened and a predetermined amount of oil is stored, and the oil level is the oil communication opening 61x.
It is set slightly higher than the height of. More specifically, before starting the engine, the front chamber C1, the middle chamber C2, the rear chamber C
3 and the relay chamber C4 are all at the illustrated oil level OL. On the other hand, after the engine is started, the oil level OL in the front chamber C1 into which the drain oil flows due to the operation of the HST rises, and the auxiliary hydraulic pump 420 sucks the stored oil in the middle chamber C2. Oil level OL
Will fall.

Further, reference numeral 61x 'in FIGS. 6 and 8
Is an oil communication opening provided below the front support wall 61a and connecting the lower portion of the front chamber C1 and the middle chamber C2. The oil communication opening 61x ′ is not for positively inflowing oil from the front chamber C1 to the middle chamber C2, but for preventing oil from remaining in the front chamber C1 when removing oil from the transmission case. It is a thing. Therefore, the oil communication opening 61x 'is made as small as possible.

The front support wall 61a is located substantially in the center in the vehicle width direction, and the PTO system input shaft 31 and the traveling system input shaft 3 are provided.
The rear end of each of the four is supported. That is, the PTO system input shaft 31 and the traveling system input shaft 34 are both supported by the front lid portion 62 and the front support wall 61a in a state where they are vertically arranged side by side in the approximate center of the vehicle width direction. More specifically, as shown in FIGS. 2, 3 and 6, the PTO system input shaft 31 is arranged such that the rotation axis is arranged along the front-rear direction in the approximate center of the transmission case 60 in the width direction. Further, the front end portion is supported by the front lid portion 62 so as to be connectable to the pump shaft, and the rear end portion is finally supported by the front support wall 61a.

On the other hand, the traveling system input shaft 34 is substantially centered in the width direction of the mission case 60 and the PTO system input shaft 3 is provided.
Below 1, the rotation axis is along the front-back direction,
A front end portion is supported by the front lid portion 62 so as to be connectable to the motor shaft, and a rear end portion is finally supported by the front support wall 61a. The rear support wall 61b supports the front end portion of the rear PTO shaft 32. That is, the rear PTO shaft 32 is supported by the rear support wall 61b and the rear lid 63. More specifically, the rear PTO shaft 32 has the rear support wall 61b such that the rotation axis is along the front-rear direction and the rear end portion projects rearward from the rear lid portion 63 substantially at the center in the width direction of the mission case. And is supported by the rear lid 63.

The front lid portion 62 is connected to the body portion 61 so as to close the front opening of the body portion 61 and supports the center section 23. That is, the center section 23 is connected to the front cover while supporting the hydraulic pump body 21 and the hydraulic motor body 22. In addition, in this Embodiment, although it comprised so that the front cover part 62 which blocks the front opening of the main-body part 61 may be provided, it replaces with this and the front opening of the main-body part 61 is made into the center section 2.
It is also possible to configure so as to be closed at 3.

The mid PTO shaft 33 is the chassis 10
First working device 11 such as a mower disposed below the central portion of
Therefore, the front of the mission case 60 is located below the mission case 60 such that the rotation axis extends along the vehicle front-rear direction and the front end portion projects forward from the mission case 60. It is supported by the support wall 61a and the rear support wall 61b. The mid P
The input shaft 112 (see FIG. 1) of the first working device 112, which is operatively connected to the TO shaft 33, extends from the center in the width direction in order to prevent interference with the chassis 101 while preventing an increase in vehicle height as much as possible. It is preferably displaced to either one. In the present embodiment, as described above, the mission case 60
The differential gear device 1 on the lower side of one side in the width direction of the
50 are accommodated. Therefore, the input shaft 112 of the first working device 112 is displaced to the other side in the width direction opposite to the side to which the differential gear device 150 is displaced, and the mid PTO shaft 33 is also displaced to the other side in the width direction. Is preferred. By configuring in this way,
It is possible to suppress an increase in vehicle height, prevent interference with the differential gear device 150, and simplify a transmission mechanism that connects the mid PTO shaft 33 and the input shaft 112 of the first working device 112.

Further, in the present embodiment, as shown in FIG. 3, in order to bring the mid PTO shaft 33 as close as possible to the ground, the mid PTO shaft 33 is connected to the pair of drive shafts 18.
It is arranged below 0. With such a configuration, the transmission mechanism that connects the mid PTO shaft 33 and the first working device 112 can be configured without difficulty. That is, the first
The work device 112 is configured so as to be able to take a working state in which it is placed on the ground and a standby state in which it is lifted and lowered from the ground. Therefore, the first working device 112 and the mid PTO shaft 33 are connected by a transmission mechanism having a universal joint. In such a case, if the mid PTO shaft 33 is arranged as close to the ground as possible, the first working device 112
In the working state, the bending angle of the universal joint with respect to the mid PTO shaft 33 can be made small, which makes it possible to configure the transmission mechanism including the universal joint without difficulty. In FIG. 1, reference numeral 112 'indicates a front PTO device. In the present embodiment, the front PTO device 112 'is detachably suspended and supported on the bottom surface of the front axle 10e. The front PTO device 112 ′ is used when a working machine such as a snow blower is mounted on the front part of the vehicle instead of mounting the first working device 112 such as the mower described above on the lower abdomen of the vehicle. Specifically, the front P along the longitudinal direction of the vehicle
The mid-PTO shaft 33 is connected to the rear end of the TO shaft via a shaft joint, and the front end of the front PTO shaft is connected to the drive unit of the working device via a shaft joint.

As shown in FIG. 3, FIG. 6, FIG. 7 and FIG. 9, the PTO system transmission mechanism 40 is a mission along the vehicle front-rear direction and across the relay chamber C4 and the rear chamber C3. PTO system transmission shaft 4 supported by the case 60
1 and the PTO system transmission shaft 4 from the PTO system input shaft 31.
1, a PTO clutch device 70 for turning on / off power transmission to the vehicle 1, the PTO system transmission shaft 41, and the rear PTO shaft 3
The rear PTO gear train 42 that connects the two
Mid-PTO transmission gear train 43 connecting between the O-system transmission shaft 41 and the mid-PTO shaft 33, and power from the PTO-system transmission shaft 41 to the rear PTO gear train 42 and / or the mid-PTO transmission gear train 43 And a switching device 45 for turning transmission on / off.

The PTO system transmission shaft 41 is shown in FIGS.
As well shown in FIG. 2, the rotational axis is the vehicle longitudinal direction on the other side in the vehicle width direction opposite to the one side in the vehicle width direction where the differential gear device storage space is displaced, with respect to the PTO system input shaft 31. It is supported by the front support wall 61a and the rear lid portion 63 so that the rear end portion thereof reaches the rear portion of the mission case 60 along. The PTO system transmission shaft 41 serves as a drive shaft for the mid PTO shaft 33 and the rear PTO shaft 32. As mentioned above, the mid PTO shaft 33
Is arranged below the mission case 60, while the rear PTO shaft 32 is arranged above the mission case 60. Therefore, in the present embodiment, as shown in FIG. 6, the PTO system transmission shaft 41 to the mid P
The PTO system transmission shaft 41 is disposed below the PTO system input shaft 31 so that power transmission to both the TO shaft 33 and the rear PTO shaft 32 can be performed efficiently and with a simple structure.

The PTO clutch device 70 is arranged in the front chamber C1 of the mission case 60 as shown in FIG. That is, in the present embodiment, the power from the PTO system input shaft 31 to the PTO system transmission shaft 41 is turned on / off in front of the mission case 60. Specifically, the PTO clutch device 70
Is a drive side member 71 supported by the PTO system input shaft 31 so as not to be relatively rotatable and axially slidable, a drive side friction plate 72 supported by the drive side member 71, and the PTO system input shaft 31. A driven member 73 rotatably supported by the driven member 73.
And a driven-side friction plate 74 which is supported by the driven-side member 73 so as to be relatively non-rotatable and slidable in the axial direction, and the driven-side friction plate 74 and the driving-side friction plate 72 under the action of hydraulic pressure. A clutch pushing member 75 to be frictionally engaged, and the driving side friction plate 72 and the driven side friction plate 7 for the clutch pushing member 75.
A clutch urging member 76 for separating from the No. 4 and a PTO transmission gear 77 supported by the front end portion of the PTO system transmission shaft 41 so as to mesh with the driven side member 73 so as not to rotate relative to each other. The PTO clutch device 70 having such a configuration
Is the PTO when the clutch pushing member 75 frictionally engages the friction plates 72, 74 by the action of hydraulic pressure.
It functions as a main PTO gear train that transmits power from the system input shaft 31 to the PTO system transmission shaft 41 via the driven side member 73, and when it is not affected by hydraulic pressure, the PTO
It functions as a blocking member that blocks power transmission from the system input shaft 31 to the driven member 73.

In the present embodiment, the PTO clutch device 70 is further provided with a PTO brake mechanism 80 interlocked with the clutch operation of the PTO clutch device 70, whereby the PTO clutch device 70 is powered off. In doing so, the rear PTO shaft 32 and the mid PTO shaft 33 are effectively prevented from continuing to rotate due to the inertial force of the connected working device.

The PTO brake mechanism 80 includes a brake disc 81 (in this embodiment, an outer peripheral surface of the driven side member 73) provided on the driven side member 73 so as not to rotate relative to the driven side member 73, and the brake disc 81. And a brake shoe 82 disposed so as to be frictionally engageable with each other, a tip end portion thereof supports the brake shoe 82, and a base end portion thereof is slidable in an axial direction in a cylinder chamber 85 provided in the mission case 60. A supported brake pushing member 83 and a brake pushing member 84 for pushing the brake pushing member 83 so that the brake shoe 82 can frictionally engage with the brake disc 81. When the brake pushing member 83 is not acted upon by hydraulic pressure, the brake shoe 82 causes the brake disc 82 to move due to the urging force of the brake urging member 84. 1 and multiplied by the braking force frictionally engage against the brake disc 81, on the other hand, the pressing movement member 83 when the brake pressing member 83 is subjected to the action of hydraulic
Moves in a direction away from the brake shoe 82 against the urging force of the brake urging member 84, so that the braking force is not applied to the brake disc 81. More preferably, the cylinder chamber 85 is formed in the side lid portion 64. That is, by forming the cylinder chamber 85, which is required to be liquid-tight, in the side lid portion 64, not in the body portion 61, it is not necessary to improve the processing accuracy of the body portion 61, and the body portion 61 is relatively It can be easily cast.

The hydraulic action on the brake pushing member 83 is interlocked with the hydraulic action on the clutch pushing member 75. That is, the hydraulic pressure acts on the clutch pushing member 75 to cause the clutch device 70 to move.
Is in the “on” state, the brake pushing member 8
In the case where the hydraulic pressure is applied to 3 as well, the brake mechanism 80 is in the “OFF” state, while the hydraulic pressure is not applied to the clutch pushing member 75 and the clutch device is in the “OFF” state. The brake mechanism 80 is in the “on” state without hydraulic pressure acting on the brake pushing member 83. That is, the hydraulic brake mechanism 80 and the hydraulic clutch device 70 are interlocked and controlled by a common hydraulic source.

In the present embodiment, a PTO line 602 that receives pressure oil from an auxiliary pump 420 described later is used as a common hydraulic pressure source for the hydraulic brake mechanism 80 and the hydraulic clutch device 70. More specifically, the PTO
A valve assembly 650 provided with a switching valve 604 for controlling the supply of hydraulic oil from the line 602 to the hydraulic brake mechanism 80 and the hydraulic clutch device 70 is provided at the side cover 64.
Is stuck to the outer surface of.

Inside the side cover 64, a pressure oil distributor is provided inside the side cover 64 for branching the pressure oil of the PTO line 602 to the hydraulic brake mechanism 80 and the hydraulic clutch device 70. ing. In the present embodiment, the outer end portion of the side lid portion 64 has the PTO line 60.
Perforation 61 communicating with 2 and having an inner end opening to the inner surface
5 are provided. Further, as the pressure oil distributor,
One end portion 616a communicates with the inner end portion of the perforation 615, and the other end portion faces the clutch pushing member 75 and the brake pushing member 83, respectively.
b, 616c is provided as the manifold 616. The first opening end 616b and the second opening end 616
c respectively constitutes a clutch line 611 and a brake line 612 which will be described later. In addition, in the present embodiment, as shown in FIG.
b is oriented in the vehicle width direction, and the second opening end portion 616
c is facing the front-back direction of the vehicle. Preferably, the first
At least one of the open end portion 616b and the second open end portion 616c can be configured by a separable member such as a pipe, and thus, the workability and assemblability of the manifold can be improved.

In the present embodiment, the brake mechanism 80 is provided with an accumulator function 80a for alleviating a shock when the PTO clutch device 70 is switched from the power cut-off state to the power transmission state (see FIG. 13 below). ). Specifically, the brake pushing member 8
3 is a rod 83a whose base end is located in the cylinder chamber 85 and whose front end is provided with the brake shoe 82.
A pressure receiving plate 83b axially slidably supported by the rod 83a and defining the cylinder chamber 85 as a pressure oil working chamber 85a and a biasing member storage chamber 85b, and the biasing member storage chamber 85b. The rod 83a is provided with a driven plate 83c that is axially immovably supported so as to be located inside. The pressure receiving plate 83b has an orifice 85b 'which connects the pressure oil working chamber 85a and the biasing member storage chamber 85b.
Are formed. The orifice 85b 'has a structure in which the pressure receiving plate 85b is actuated by pressure oil and the biasing member storage chamber 85
When it is pushed a predetermined stroke toward b, the driven plate 83
It is designed to be closed by c.

The PTO brake mechanism 80 having the above structure operates as follows. That is,
When pressure oil is supplied through the PTO line 602,
The hydraulic pressures of the clutch line 611 and the brake 612 increase. At this time, pressure oil leaks from the orifice 85b ', so that the oil pressures in the clutch line 611 and the brake line 612 initially rise relatively slowly.
Therefore, the hydraulic clutch device 70 is gently brought into the engaged state. After that, when the pressure receiving plate 85b is pushed by pressure oil and the orifice 85b ′ is closed, the hydraulic pressures of the clutch line 611 and the brake line 612 become
Increase to the set value.

As described above, in this embodiment, the clutch line 611 is maintained until the pressure receiving plate 85b is pushed for a predetermined stroke to close the orifice 85b '.
The hydraulic pressure of can be gradually increased. Therefore, it is possible to prevent sudden engagement of the hydraulic clutch device 70 and effectively prevent wear / damage of each member.

The rear PTO gear train is housed in the rear chamber C3 of the mission case 60, as shown in FIG. More specifically, the rear PTO gear train 42 is
Rear PTO gear member 42a rotatably supported in the vicinity of the rear end of the TO transmission shaft 41, and the gear member 42a.
And an idle gear 42b that meshes with the idle gear 42b.
An intermediate shaft 42c that supports b in a relatively non-rotatable manner, and a final gear 42e that is supported in a relatively non-rotatable manner near the front end of the rear PTO shaft 32 so as to mesh with a spline 42d provided on the intermediate shaft 42c. Is equipped with.

The mid PTO transmission gear train 43 is shown in FIG.
As is best shown in FIG. 1, it is arranged behind the pair of drive axles 180. That is, the mid-PTO transmission gear train 43 is positioned behind the differential gear device 150 so as not to interfere with the differential gear device 150 housed below the inner chamber C2 of the mission case 60, and is arranged in the rear chamber. It is located in C3.
Specifically, the mid PTO transmission gear train 43 faces the rear PTO gear member 42a so as to face the PTO.
Mid PTO rotatably supported on the system transmission shaft 41
Gear member 43a, an idle gear 43b that meshes with the gear member 43a, and a final gear 43c that is non-rotatably supported at the rear end of the mid PTO shaft 33 so as to mesh with the idle gear 43b. ing.

The switching device 45 controls the rotation of the PTO system transmission shaft 41 to the rear PTO by an external operation.
Gear member 42a and / or the mid PTO gear member 43a. Specifically, the rear PTO gear member 42a and the mid PTO
Each gear member 43a has engaging elements 42a 'and 43a' arranged so as to face each other. Then, the switching device 45 includes the rear PTO gear member 42.
a and the engaging element 42 of the gear member 43a for the mid PTO
The PTO system transmission shaft 4 is located between a'and 43a '.
1. Spline hub 45a supported by 1 so as not to rotate relative to it
And the spline hub 45a and the rear PTO gear member 42a and / or the engaging elements 42a ', 43a' of the mid PTO gear member 43a so as to be axially slidable and non-rotatable relative to the spline hub 45a. And a clutch shifter 45b externally attached to the clutch shifter 45b.
And an arm 45c (see FIG. 7) for operating the.

The clutch shifter 45b is, as described above, the engaging elements 42a ', 43a' of the spline hub 45a, the rear PTO gear member and the mid PTO gear member.
With respect to the spline hub 45, the spline hub 45 is externally inserted so as not to be relatively rotatable and axially movable.
a and the rear PTO gear member 42a so that they cannot rotate relative to each other, and a rear PTO output position, and the spline hub 45.
a and the mid PTO gear member 43a so that they cannot rotate relative to each other, the mid PTO output position, the spline hub 45a, the rear PTO gear member 42a, and the mid PTO.
Both PTO output positions for connecting both of the gear gear members 43a so as to be relatively non-rotatable.

The traveling system transmission mechanism 50 is shown in FIGS.
As best shown in FIGS. 6 and 8, the transmission shaft (traveling shaft) supported by the mission case 60 is adjacent to one side of the traveling system input shaft 34 in the vehicle width direction and has a rotation axis along the vehicle front-rear direction. System transmission shaft) 51 and the traveling system input shaft 3
4 and the traveling system transmission shaft 51, a multi-stage transmission device 52 for transmitting / disconnecting a shift, a front wheel power take-out device 53 optionally provided, the transmission shaft 51 and a ring gear 151 of the differential gear device 150. And a traveling brake device 200 that is interposed between and. The traveling system transmission shaft 51 is arranged in front of the differential gear device 150 housed on one side in the width direction of the transmission case 60. That is, the traveling system transmission shaft 51 is in the transmission case width direction in the same direction as the differential gear device 150 is displaced with reference to the traveling system input shaft 34 disposed substantially in the center of the transmission case 60 in the width direction. It has been displaced to one side.

The multi-stage transmission 52 includes a drive-side gear 52a supported by the traveling system input shaft 34 so as not to rotate relative to each other.
And a plurality of (two in the present embodiment) driven gears that mesh with the drive gear 52a.
A driven side member 52b which is relatively non-rotatable and slidably supported in the axial direction, and an operating member (not shown) for moving the driven side member 52b in the axial direction of the transmission shaft 51,
By engaging one of the driven gears with the driving gear 52a, the driving force can be changed and transmitted from the traveling system input shaft 34 to the traveling system transmission shaft 51.

The front wheel power take-off device 53 is arranged in the front part of the mission case 60 on the one side in the width direction of the mission case 60 and on the lower side with respect to the traveling system transmission shaft 51. That is, the front wheel power take-off device 53 is disposed in front of the mission case 60, on the one side in the width direction and below the traveling system input shaft 34 and the traveling system transmission shaft 51. Specifically, the front wheel power take-out device 53 includes a front wheel drive force take-out shaft 53a that is supported below one side in the width direction of the mission case 60 so that a front end portion thereof extends forward from the mission case 60, A gear train 53 with a clutch that connects the traveling system transmission shaft 51 and the front wheel driving force output shaft 53a.
and b.

The traveling brake device 200 is configured to be operated by a single brake pedal 205 (see FIG. 1) arranged on the left step provided on the chassis 101. Specifically, as shown in FIGS. 3, 5 and 8, the traveling brake device 200 includes a brake shaft 201 supported in the mission case 60 along the vehicle width direction, and the transmission shaft 51. A drive-side bevel gear 202 supported on the rear end of the drive-side bevel gear 202 and a driven-side bevel gear 2 supported on the brake shaft 201 so as to mesh with the drive-side bevel gear 202 so as not to rotate.
03, an output gear 204 provided on the brake shaft 201 so as to mesh with the ring gear 151, and a brake mechanism 210 for stopping the rotation of the brake shaft based on an external operation.

As shown in FIG. 8, the brake mechanism 21
Reference numeral 0 denotes a brake lid 218 connected to the other side of the main body portion 61 of the mission case 60 in the vehicle width direction, and in cooperation with the main body portion 51, the relay chamber located above the inner chamber C2. A brake lid 218 defining C4, a drive side friction plate 211 supported by the brake shaft 201 so as not to be rotatable relative to each other and axially slidable, and the mission case 60 so as to face the drive side friction plate 211. It has a driven side friction plate 212 that is supported so as not to rotate relative to it, and a pushing surface 213a that faces the driving side friction plate 211, and is supported so as to be relatively rotatable and axially movable around the axis of the brake shaft 201. Ring-shaped pushing member 213 and the pushing member 2
13, a cam groove formed on the back surface 213b on the opposite side of the pushing surface 213a, the inclined cam groove 213c being formed so as to become deeper toward one side in the circumferential direction of the pushing member 231; A ball 214 disposed in the inclined cam groove 213c and a ball holding formed on the inner surface of the brake lid 218 facing the back surface 213b of the pushing member 213 so as to hold the ball 214 immovably. The recess 215 and the inner end are connected to the pushing member 213 via a cam, and the outer end is the transmission case 60.
A connecting arm 216 that is supported by the brake lid 218 so as to be rotatable relative to the brake lid 218 so as to extend outward, and that rotates the pushing member 213 in the circumferential direction by rotation around an axis, and the connecting arm 216. An operation member for connecting the outer end of the arm 216 and the brake pedal 205 (see FIG. 1), and an operation member 217 for rotating the connection arm 216 around the axis based on the operation of the brake pedal 205. Is equipped with.

In the brake mechanism 210 having such a structure, the ball 214 moves the pushing member 213 in the brake axial direction by operating the operating member 217 to rotate the pushing member 213 to one side in the circumferential direction. By pushing, the drive side friction plate 211 frictionally engages with the driven side friction plate 212, and the rotation of the brake shaft 201 is stopped.

Preferably, the pushing member 213 holds the ball 214 between itself and the brake lid 218, and can move relative to the brake lid 218 by a stroke of the brake operation. The brake lid 218
Are linked to.

Specifically, the pushing member 213 has a plate body 213d having a central hole extending in the axial direction of the brake shaft 201, and a substantially cylindrical shape elastically engaged in the central hole of the brake body 213d. And a connecting member 213e. The connecting member 213e has a flange portion that extends outward in the radial direction at the base end portion, and has a female screw portion formed at the tip end portion. Then, the connecting member 213e is
The flange portion is inserted in the center hole of the plate body 213d in a state of being compressed inward in the radial direction, and the plate body 213d is restored by the restoring force of the flange portion.
Is elastically connected to. The connecting member 21 having such a configuration
3e is provided with the brake lid 21 via a screw member 209.
8 by which the plate body 2 is connected.
13d is the brake shaft 2 with respect to the brake lid 218.
01 is movable in the axial direction.

Further, in the central hole of the plate main body 213d, the stop piece 2 is provided at a portion separated from the abutting portion of the connecting member 213e with the flange portion on the rear surface side by a predetermined distance.
13f is provided. The stop piece 213f defines a movable range of the plate body 213d with respect to the brake lid 218. That is, the distance between the abutting position of the flange in the central hole and the stop piece 213f corresponds to the brake actuation stroke.

With this structure, the brake lid 218 is connected to the pushing member 213 so that the ball 214 is held between the brake lid 218 and the brake lid 218. Can be assembled to the main body 61 of the mission case 60. Therefore,
It is possible to improve the assembly efficiency of the brake mechanism 210 while obtaining a sufficient braking function by the brake mechanism 210.

Further, the traveling system transmission mechanism 50 has a differential lock mechanism 250 for locking the differential gear device 150. The diff lock mechanism 250 is
The pair of drive shafts 180 is interlocked with the rotation of the ring gear 151.
The bevel gear 154 pivotally supported on the pivot shaft 153 so as to mesh with the pair of side bevel gears 152 that are revolvable around and are relatively non-rotatably supported by the pair of drive shafts 180, respectively. The rotation around the shaft 153 can be forcibly locked (FIG. 5).
reference).

Specifically, the diff lock mechanism 250 is
As shown in FIGS. 5 and 8, the ring gear 151 and one of the pair of side bevel gears 152 are configured so as to have a locked position for relatively non-rotatably connecting and a release position for relatively rotating both. Locking member 251 and
A differential lock fork shaft 252 supported by the mission case 60 so as to be movable in the axial direction along the vehicle width direction, the differential lock fork shaft 252 being movable along the axial direction based on an operation from the outside of the mission case. ,
A base end of the differential lock fork 253 is supported by the differential lock fork shaft 252 so as to be slidable in the axial direction and a distal end of the differential lock fork 253 engages with the lock member 251, and the base end of the differential lock fork 253 is connected to the differential lock fork shaft 252. A pair of first and second return springs 25 sandwiched and supported
4a, 254b and a first stop member 255a externally inserted to the diff lock fork shaft 252 so as to abut the outer end of the first return spring 254a, the diff lock fork shaft 252 being on one side in the axial direction. A first stop member 255a configured to move together with the diff lock fork shaft when moving in the (locking direction), and an inner end portion of the first stop member 255a abuts an outer end portion of the second return spring 254b and an outer end portion of the second return spring 254b. A second stop member 255b externally inserted to the diff-lock fork shaft 252 so that the portion contacts the inner surface of the side lid 64, and the d-lock fork shaft is configured to be relatively movable in the axial direction. 2 stop member 255b.

The differential lock mechanism 250 having such a structure operates as follows. That is, when the diff lock fork shaft 252 is moved to one side in the axial direction, the first stop member 255a compresses the first return spring 254a, and the diff lock fork 253 receives the elastic force of the first return spring 254a. The second return spring 254b is moved while being compressed to move the lock member 251 to the lock position. Then, when the operation force applied to the differential lock fork shaft 252 is released, the second return spring 254 that is compressed is compressed.
The diff lock fork 253 and the diff lock fork shaft 252 are returned to the other side in the axial direction (release direction) by the biasing force of b, whereby the lock member 251 is moved to the release position.

Thus, the differential lock mechanism 250
Locks the differential gear device 150 when an operation force is applied to the differential lock fork shaft 252, and automatically releases the operation force when the operation force is released.
The lock of 0 is released.

Further, the traveling system transmission mechanism 50 is a link mechanism 300 for simultaneously stopping both of the pair of drive shafts 180 when the traveling brake device 200 is operated.
Is equipped with. That is, the traveling brake device 200 is
As described above, the braking force is applied to the brake shaft 201 arranged on the front side of the differential gear device. Therefore, the differential gear device 1
When the brake device 200 is operated without locking 50, a "difference in stop time" occurs between the pair of drive shafts 180 due to the difference in the load applied to each of the pair of drive wheels 180.
May occur. Such "shift" means that the other drive wheel continues to rotate even though one drive wheel is stopped, and the vehicle slides laterally when stopped. Therefore, when operating the traveling brake device 200, it is necessary to lock the differential gear device 150.

On the other hand, in the case where one of the pair of drive wheels slips due to a depression or the like, the differential gear unit 150 is provided in order to transmit sufficient power to the other drive wheel.
Need to be locked. In such a case, naturally, it is necessary to operate (lock) only the differential lock mechanism 250 without operating the traveling brake device 200.

The link mechanism 300 is provided to meet such a request, and the traveling brake device 20 is provided.
When the operation is 0, the diff lock mechanism 250 can be forcibly operated (locked) while the diff lock mechanism 250 alone can be operated (locked).

Specifically, as shown in FIG. 8, the link mechanism 300 is swingably supported around the pivot shaft 301 so as to move the differential lock fork shaft 252 along the axial direction. A moving member 302, a diff lock operating member 303 whose tip is directly or indirectly connected to the swinging member 302, a tip end is locked to the swinging member 302, and a base end is the brake device 200. When the connecting arm 216 rotates in the direction of operating the traveling brake device 200, the long connecting member 304 moves in the direction of the swinging member 302 in conjunction with the rotation. It has and.

The rocking member 302 includes the rocking member 30.
First and second elongated holes 305, 306 along the swinging direction of 2
The diff lock operating member 303 and the connecting member 304 are respectively fitted at their tips into the first and second elongated holes 305 and 306, respectively. The first
The long hole 305 is the end portion 30 on one side in the swing direction in which the swing member 302 pushes the differential lock fork shaft 252.
5a and the swinging member 302 are the differential lock fork shaft 2
It extends between the end portion 305b on the other side in the swing direction which is separated from 52. Similarly, the second elongated hole 306 also extends between the one end 306a and the other end 306b of the swing member 302 in the swing direction.

FIG. 10 shows a partial cross-sectional plan view of the vicinity of the brake shaft in the transmission. Figure 10 (a)
And (b) respectively show a state in which the traveling brake device 200 is operated and a state in which only the differential lock device is operated independently.

As shown in FIG. 8, when both the traveling brake device 200 and the diff lock mechanism 250 are in the non-operating state, the tip portions of the diff lock operating member 303 and the connecting member 304 respectively have the first and second positions. One end portion 305a of the first and second elongated holes 305, 306 in the swinging direction,
It is located at 306a. When the brake device 200 is operated from this state, the connecting member 304 moves in the direction of the swinging member 302 and swings the swinging member 302 to one side in the swinging direction. Therefore, the diff lock fork shaft 252 is pushed by the swing member 302 (see FIG. 10 (a)).

On the other hand, when only the differential lock mechanism 250 is operated independently from the state shown in FIG.
As shown in (b), the rocking member 302 is rocked to one side in the rocking direction by the diff lock operating member 303, thereby moving the diff lock fork shaft 252 but not the connecting member 304. It has become. That is, even when the swing member 302 swings to one side in the swing direction, the second elongated hole 306 prevents the connecting member 304 from moving.

As described above, the link mechanism 300 has the diff lock mechanism 2 when the traveling system brake device 200 is operated.
Diff lock mechanism 250 while forcibly locking 50
Only the operation is allowed.

In the transmission 30 having such a structure, the following effects can be obtained in addition to the above-mentioned various effects. That is, the PTO system input shaft 31 and the traveling system input shaft 3
4 are vertically distributed in the approximate center in the width direction of the mission case 60, and the PTO system transmission mechanism 40 following the PTO system input shaft 31 is arranged on the other side of the mission case 60 in the width direction with reference to the PTO system input shaft 31. Since the traveling system transmission mechanisms 50 that are integrated in the transmission system input shaft 34 and that follow the latter stage of the traveling system input shaft 34 are aggregated on one side and the lower side in the width direction of the mission case 60 with the traveling system input shaft 34 as a reference, While effectively compressing the width and the vertical width, the upper space of the traveling system transmission mechanism 50 in the mission case can be secured as a storage space for other members. It should be noted that, for example, a cylinder tube 401 of the hydraulic lift device 400 described later can be stored in the storage space for the other members.

Further, from the PTO system transmission shaft 41 to the mid P
The power transmission to the TO shaft 33 is configured to be performed by the mid-PTO transmission gear train 43 arranged behind the differential gear device 150. Therefore,
The tip position of the mid PTO shaft 33 (driving force extraction position)
Can be as close to the pair of axles 180 as possible. In this way, the tip position of the mid PTO shaft 33 is set to the axle 1
The fact that it can be placed close to 80 means that the distance between the tip of the mid PTO shaft 33 and the first working device 112 driven by the mid PTO shaft 33 can be made large, whereby the first work device 112 can be made larger. The first working device 112 and the mid PTO shaft 3 when the working device 112 is raised
The mid P of the universal joint in the transmission mechanism that connects the
The bending angle with respect to the TO shaft 33 can be reduced. Therefore,
The first working device 112 can be raised and lowered without difficulty,
It is possible to obtain effects such as reduction of noise and improvement of durability.

Further, in the transmission 30, as described above, the PTO system transmission shaft 41 is displaced to the other side in the width direction of the transmission case 60. The mid PTO shaft 33 is also displaced to the other side in the width direction of the mission case 60. Therefore, the linear distance between the PTO system transmission shaft 41 and the mid PTO shaft 33 can be reduced. Further, the traveling system transmission mechanism 50 is arranged in front of the mission case 60 in the front-rear direction, and
A mid PTO transmission gear train 43 that connects the system transmission shaft 41 and the mid PTO shaft 33 is arranged behind the mission case 60, whereby the mid PTO gear train 43 is arranged.
Can be arranged on a virtual straight line connecting the PTO system transmission shaft 41 and the mid PTO shaft 33. Such a linear arrangement allows the mid-PTO transmission gear train 43 to be reduced and simplified as much as possible.

Further, in the transmission 30, a rear PTO gear train 42 for transmitting power from the PTO system transmission shaft 41 to the rear PTO shaft 32 is provided with an idle gear 42b and an intermediate shaft 42c, and these members are provided. The PTO system transmission shaft 41 is arranged on one side in the vehicle width direction, whereby the PTO system transmission shaft 41 is arranged.
From the rear to the rear PTO shaft 32,
The expansion of the mission case 60 is effectively suppressed. That is, generally, from the PTO system transmission shaft 41 to the rear PTO.
It is necessary to decelerate and transmit the driving force to the shaft 32. Temporarily, the rear PTO gear member 42 a supported by the PTO system transmission shaft 41 and the final gear 4 supported by the rear PTO shaft 32.
If it is directly meshed with 2e, the pitch circle radius of the rear PTO gear member 42a must be increased, and the axial distance between the PTO system transmission shaft 41 and the rear PTO shaft 32 becomes long, As a result, mission case 6
This leads to an increase of 0.

In view of this point, in the present embodiment, as described above, the idle gear 42b and the intermediate shaft 42c are provided between the rear PTO gear member 42a and the final gear 42e.
And the idle gear 42b and the intermediate shaft 42c are arranged on one side of the PTO system transmission shaft 41 in the vehicle width direction. That is, as shown in FIG. 7, the PTO system transmission shaft 41 is arranged on the other side in the width direction of the mission case with respect to the position of the mission case 60 in the width direction with respect to the PTO system input shaft 31 and the traveling system input shaft 34. The upper and lower positions are arranged between the input shafts 31 and 34. Here, the traveling system transmission mechanism 50 is
As described above, they are collectively arranged on one side and the lower side in the width direction of the mission case with the traveling system input shaft 34 as a reference. Therefore, on the one side in the width direction of the PTO system transmission shaft 41 at the rear of the mission case 60 in the front-rear direction,
There is free space. In the transmission 30, the idle gear 42b and the intermediate shaft 42c are arranged in the empty space, whereby the transmission case 41 transmits the deceleration from the PTO system transmission shaft 41 to the rear PTO shaft 32. Effectively prevents the expansion of.

The vehicle 100 according to the present embodiment further includes a hydraulic lift device 400 for raising and lowering a working device such as a cultivator disposed behind the chassis 10, and pressure oil supply / discharge for the hydraulic lift device 400. A valve unit 410 for controlling, an auxiliary pump 420 for supplying pressure oil to the valve unit 410, and an auxiliary pump transmission mechanism 430 for transmitting the driving force from the PTO system input shaft 31 to the auxiliary pump 420. Is equipped with.

The hydraulic lift device 400 is shown in FIGS.
As well shown in FIG. 1, a cylinder tube 401 arranged along the vehicle front-rear direction, a piston head 402 housed in the cylinder tube 401 in a reciprocating manner and liquid-tight, and a tip end portion of the piston head 402. A piston rod 403 having a rear end portion extending rearward from a rear end opening of the cylinder tube 401, a support shaft 404 supported along the vehicle width direction, and a base end portion of the support shaft 404. An arm 40 that is supported by the piston rod 403 so that it cannot rotate relative to the other end and is connected to the rear end of the piston rod 403.
5 and a pair of lift arms 406 whose base ends are supported by the support shaft 404 so that they cannot rotate relative to each other and whose front ends extend rearward of the chassis.
By applying pressure oil to the two, the pair of lift arms 406 can be swung around the axis of the support shaft 404. Incidentally, reference numeral 405a in FIG.
Is a spacer for fixing the position of the arm 405.
Reference numeral 60f in FIG. 4 is a breather pipe that communicates the internal air layer of the mission case 60 with the outside air in order to absorb the volume change due to the temperature change of the stored oil.

Here, the cylinder tube 401,
The installation positions of the valve unit 410 and the auxiliary pump 420 will be described in detail. First, the cylinder tube 40
The vertical position of No. 1 will be described. The cylinder tube 401 is disposed above the PTO system input shaft 31 (or the pump shaft 21a), thereby preventing interference with the PTO system transmission mechanism 40. is doing. The cylinder tube 401 is arranged above the PTO system input shaft 31 in the case where the cylinder tube 401 is arranged in an upper position inside the mission case 60 and when it is arranged on the upper surface of the mission case 60. It is included when it is set.

Next, regarding the position of the cylinder tube 401 in the vehicle width direction,
Is disposed on one side of the transmission case 60 in the vehicle width direction. The front opening of the cylinder tube 401 is closed by the valve unit 410. That is, the cylinder tube 401 and the valve unit 410 are continuously provided on one side of the transmission case 60 in the vehicle width direction along the vehicle longitudinal direction.
Preferably, a recess 410 ′ into which the cylinder tube 401 is fitted can be formed on the surface of the valve unit 410 facing the cylinder tube 401, which improves the assembly efficiency of the valve unit 410 and the cylinder tube 401. Can improve.

On the other hand, the auxiliary pump 420 is located on the other side of the valve unit 410 and the cylinder tube 401 in the vehicle width direction.
It is supported by 0.

As described above, in the present embodiment, the valve unit 410 and the cylinder tube 401 are
Is arranged on one side in the vehicle width direction of the mission case 60,
In addition, the auxiliary pump 420 is arranged on the other side of the transmission case 60 in the vehicle width direction, whereby the following effects are obtained.

That is, in the conventional working vehicle, the valve unit and the cylinder tube are arranged on the upper surface of the transmission case along the longitudinal direction of the vehicle, and the auxiliary pump for supplying pressure oil to the valve unit is It was supported by the rear wall of the mission case. Therefore,
When the stored oil in the mission case is supplied to the cylinder tube, it is necessary to once draw the stored oil from below the mission case to the rear of the mission case and then supply it to the cylinder tube via the valve unit on the upper surface of the mission case. Yes, there was a problem that the oil distribution route becomes long. Such lengthening of the oil distribution path means increase in size of the hydraulic pump due to pressure loss, increase in size of the vehicle due to increase in piping space, decrease in reaction speed of the hydraulic device due to decrease in pressure oil supply speed to the hydraulic device, etc. Invite.

On the other hand, in the present embodiment, as described above, the valve unit 410 and the cylinder tube 401 are continuously provided along the vehicle longitudinal direction on one side in the vehicle width direction of the mission case 60, and the valve unit The auxiliary pump 420 is arranged on the other side in the vehicle width direction of 410 and the cylinder tube 401. Therefore, the oil flow path for supplying the hydraulic oil from the mission case 60 to the valve unit 410 via the auxiliary pump 420 can be shortened, and as a result, the auxiliary pump 420
Can be downsized, the vehicle can be downsized, and the reaction speed of the hydraulic system can be increased.

Preferably, in the mission case 60, a stored oil outlet 65 (see FIGS. 2 and 3) is provided at substantially the same position as the auxiliary pump 420 in the vehicle longitudinal direction, and the stored oil outlet 65 and the auxiliary pump are provided. The suction port of 420 can be fluidly connected, which can further shorten the oil circulation path.

FIG. 11 shows a sectional view taken along line XI-XI in FIG. As shown in FIGS. 3 and 11, more preferably, a strainer 66 sandwiched between the main body portion 61 and the side lid portion 64 is provided below the middle chamber C2 of the mission case 60, and the strainer 66 is provided. The stored oil can be taken out from the stored oil take-out port 65 via the above, whereby impurities in the iron powder can be effectively removed. The stored oil outlet 65 is provided in a cover detachably attached to a side opening of the main body 61,
Strainer 66 in the case by removing this cover
You can access to.

In this embodiment, as shown in FIGS. 3 to 5, the main body portion 6 of the mission case 60 is
1, a first bulging portion 61c bulging upward on one side in the vehicle width direction is integrally provided, and the cylinder tube 401 is arranged in the first bulging portion 61c. The installation position of the tube 401 is lowered to reduce the vehicle height.

That is, when the cylinder tube is installed on the upper surface of the mission case, a separate member for supporting the cylinder tube is required and the installation position of the cylinder tube becomes high. Therefore, the manufacturing cost is increased due to the increase in the number of parts, and the vehicle height is increased. In general, the driver's seat is often arranged above the cylinder tube (see FIG. 1). Therefore, the higher the position of the cylinder tube, the higher the position of the driver's seat. This will make it difficult to climb and get in and out of the driver's seat.

On the other hand, in this embodiment, the cylinder tube 401 is connected to the first case of the mission case 60.
Since it is housed in the bulging portion 61c, the installation position of the cylinder tube 401 can be lowered and the cylinder tube 401 can be stably supported.

Further, by accommodating the cylinder tube 401 in the mission case 60, the support shaft 404 can be supported by the mission case 60 without requiring a special mechanism, thereby reducing the manufacturing cost. It is possible to hold the support shaft 404 in a stable manner. In the present embodiment, as well shown in FIG. 4, the support shaft 404 is arranged so that both ends of the support shaft 404 extend outward from both side walls of the mission case 60, respectively. To support
Each of the pair of lift arms 406 is connected to the extending portions of both ends.

Preferably, as shown in FIGS. 3 and 7,
A lip 61d may be provided on the bottom wall of the first bulging portion 61c to prevent the cylinder tube 401 from coming out backward. Accordingly, the cylinder tube 401 is attached to the valve unit 410 and the lip 61.
It can be clamped by d and the cylinder tube 401 can be held more stably.

The auxiliary pump transmission mechanism 430 is housed in the front chamber C1. Specifically, as shown in FIGS. 6 and 9, the auxiliary pump transmission mechanism 430 includes a drive-side gear 431a supported by the PTO system input shaft 31 such that the drive-side gear 431a cannot rotate relative to the drive-side gear 431a. The gear train 431 includes an idle gear 431b that meshes with the idle gear 431b, and a driven gear 431c that is supported by the pump shaft 421 of the auxiliary pump 420 so as to be relatively non-rotatable so as to mesh with the idle gear 431b.

As well shown in FIG. 6, the gear train 431 is disposed above the right side portion of the PTO system input shaft 31 when viewed from the front. Disposed PTO system transmission shaft 4
1 including PTO system transmission mechanism 40 and traveling system input shaft 34
The space in the mission case is effectively used while preventing the interference with the traveling system transmission mechanism 50 disposed on the left side of the vehicle.

That is, in this embodiment, the PTO system input shaft 31 and the traveling system input shaft 34 are vertically arranged side by side in the central portion of the transmission case in the vehicle width direction, and are driven by the PTO system input shaft 31. The auxiliary pump transmission mechanism 430 and the PTO transmission mechanism 40 are separately arranged vertically on one side in the vehicle width direction, and the traveling system transmission mechanism 5 is driven by the traveling system input shaft 34.
0s are collectively arranged on the lower side of the mission case on the other side in the vehicle width direction, thereby preventing mutual interference between the transmission mechanisms and effectively utilizing the space.

Preferably, as shown in FIGS. 4 and 6,
A second swelling portion 61e, which bulges upward and is closed by the front lid portion 62, is provided at a position on the body portion 61 of the mission case 60 opposite to the first swelling portion 61c in the vehicle width direction. The auxiliary pump 420 can be supported by the second bulging portion 61e, whereby the auxiliary pump 420 can be supported and stabilized, and the cost can be reduced by reducing the number of parts. More preferably, a part of the gear train 431 can be housed in the closed space defined by the second bulging portion 61e and the front lid portion 62.

In the present embodiment, an opening 61e 'communicating with the closed space defined by the front lid portion 62 and the second bulging portion 61e is formed in the second bulging portion 61e, The pump shaft 421 from the rear through the opening 61e '.
Of the driven side gear 431c by pushing the driven side gear 431c into the closed space.
However, the present invention is not limited to such a form. That is, FIG.
As shown in FIG. 5, instead of providing the second bulging portion 61e, the closed space is formed by the front lid portion 62 and the pump mounting cover 425 connected to the front of the front lid portion 62,
An opening 425 ′ communicating with the closed space may be provided in the pump mounting cover 425, and the pump shaft 421 may be projected from the front. When the auxiliary pump 420 to be described later is of a tandem dual type, as shown in FIG. 17, the pump mounting cover 425 and the front lid portion 62 respectively have an opening 425 ′ and an opening 62 which communicate with the closed space. '
And a front lid portion 6 of the pump mounting cover 425.
2 from the rear, pump shafts 421 ', 421'', respectively
It is also possible to inject the dual pumps 420 'and 420''into front and rear, respectively, or, alternatively, to the front or rear of the bulging portion, the dual pumps 420' and 420 ''.
It is also possible to store 0 ″.

Next, the hydraulic circuit of the transmission structure according to this embodiment will be described. FIG. 12 shows the hydraulic lift device 4
00 and the valve unit 410 part, and FIG. 13 is a hydraulic circuit diagram of the center section and the PTO clutch device part. FIG. 14 is a vertical sectional front view of the center section.

The stored oil outlet 65 of the mission case 60 is connected to a suction port 420a of an auxiliary pump 420 installed above the mission case 60 via a pipe 501 (see FIG. 2). That is, the stored oil in the mission case 60 is filtered by the strainer 66 arranged in the middle chamber C2 of the mission case 60, and then the auxiliary pump 420 is sucked through the stored oil take-out port 65 and the pipe 501. It is sucked into the port 420a. Then, the pressure oil discharged from the discharge port 420b of the auxiliary pump 420 is sucked into the suction port 410a of the valve unit 410 arranged in parallel with the auxiliary pump 420 along the vehicle width direction via the pipe 502 (see FIG. 2). Is supplied to.

In the valve unit 410, the base end side communicates with the suction port 410a provided on the upper surface of the valve unit 410, and the tip end side communicates with the valve unit 41.
0 through the shunt valve built in the first and second lines 41
An inhalation line 411 branched into 2, 413 is formed.

In the present embodiment, the first line 41
An auxiliary control valve unit 450 is connected to the side surface of the valve unit 410 so that the pressure oil flowing in 2 can be selectively taken out from a plurality of take-out ports.
That is, by providing the auxiliary control valve unit 450, the pressure oil flowing through the first line 412 can be used for a hydraulic device or the like for moving the bucket device 111 (see FIG. 1) up and down and for dumping / tilting.

The auxiliary control valve unit 450
Is a unit main body 451 as shown in FIGS.
And a plurality of hydraulic lines 452 drilled in the body 451
And one or a plurality (two in the present embodiment) of the switching valve 453 interposed in the plurality of hydraulic lines 452, and a plurality of pressure oils introduced from one hydraulic line are provided. It can be taken out from the take-out port 450a. In addition, in the present embodiment, two ports of the plurality of extraction ports 450a are provided on the upper surface of the valve unit 410 (see FIG. 4).

The tip side of the first line 412 has the first
A high pressure relief valve 414 that sets the hydraulic pressure of the line 412 opens to the side surface of the valve unit and communicates with one hydraulic line of the auxiliary control valve unit 450.

As described above, the valve unit 410 has the concave portion 410 ′, so that the cylinder tube 40 has the same shape.
One front opening can be closed.

The valve unit 410 further includes
The base side communicates with the first line 412 through the auxiliary control valve unit 450, and the tip side through the recess 410 ′ through the cylinder tube 40.
1 is provided with a working oil line 415 (see FIGS. 3, 4, and 12). An elevating switching valve 416 and a stop valve 417, both of which can be operated externally, are inserted in the hydraulic oil line 415. The stop valve 417 is provided with a slow return valve 418 for preventing abrupt lowering of the lift arm 406 (see FIG. 12).

In this embodiment, as well shown in FIG. 3, the stop valve 417 is arranged horizontally, and the operating member 417a of the stop valve 417 is arranged in an upwardly inclined shape. It is set up. Specifically, the stop valve 417 and the operating member 417a are connected via a universal joint 417b, and the drive side member of the universal joint is supported by a stay 417c fixed to the valve unit 410 in an upwardly inclined shape.

The reference numeral 416a in FIGS. 4 and 5 is
It is a link mechanism for operating the up / down switching valve 416.
It is connected to a lifting operation lever 416b for switching to any of the positions. The movement of the lift arm 406 is fed back to the raising / lowering operation lever 416b to raise (or lower) the raising / lowering switching valve 416 from the neutral position.
When the tip of the lift arm 406 reaches a predetermined ascending (or descending) height after switching to the position, the lift arm 4 is lifted.
The movement of 06 is fed back, and the lifting operation lever 41
6b is forcibly returned to the neutral position.

Further, reference numeral 419 in FIGS. 4, 5 and 12
Is a drain line for returning the drain oil flowing out through the up-and-down switching valve 416 into the mission case 60. In the present embodiment, the drain line 419
Is opened in the first bulging portion 61c, and is configured to flow into the rear chamber C3 of the mission case from the first bulging portion 61c. More preferably, the rear chamber C
3 can be provided with an inner wall 61f that temporarily receives the return oil from the drain line 419 (see FIG. 3). By providing such an indoor wall 61f, the high temperature return oil from the drain line 419 can be cooled.

On the other hand, the tip side of the second line 413 is
A hydraulic circuit 500 for a power steering device, which is communicated with a discharge port 410b provided on the upper surface of the valve unit 410 and is optionally provided via a pipe 503, and a hydraulic circuit 6 for the PTO clutch device 70.
00 and the HST first charge line 23d (see FIGS. 4, 12 and 13).

In the present embodiment, the oil discharged from the single auxiliary pump 420 is divided into the first and second lines 412 and 413 by using the flow dividing valve. However, the operation of the flow dividing valve is performed. When the oil temperature rise due to the above is a problem, the auxiliary pump 420 is replaced by a tandem twin pump 420 ′, 42 ′ as shown in FIG.
0 ″, the discharge port of one pump 420 ′ can be connected to the first line 412 and the discharge port of the other pump 420 ″ can be connected to the second line 413 of the pump 420 ″. Can be resolved.

Hydraulic circuit 600 for the PTO clutch device
As shown in FIG. 13, the base end side is the second line 41.
3, a suction line 601 communicated directly with the tip side of the power steering device 3 or via the power steering device hydraulic circuit 500;
PTO line 602 branched from the suction line 601
And a HST line 603, a switching valve 604 inserted in the PTO line 602, and a high pressure relief valve 605 inserted in the HST line 603.

In the present embodiment, as shown in FIG. 5, the hydraulic circuit 60 for the PTO clutch device is mainly used.
The valve assembly 650 constituting 0 is installed on the outer surface of the upper portion of the side cover portion 64 of the mission case 60.

That is, the valve assembly 650 includes
The input port 600a to which pressure oil is supplied and the suction line 601 whose one end communicates with the input port 600a.
The PTO line 602 and the HST line 603 branched from the suction line 601, the switching valve 604 inserted in the PTO line 602, and the HST.
The high-pressure relief valve 605 inserted in the line 603.
And an output port 600b communicating with the tip of the HST line 603 (see FIGS. 5 and 12).

The PTO line 602 communicates with the perforations 615 provided in the side wall portion 64 of the mission case 60 (see FIG. 9). As a result, the pressure oil supplied from the PTO line 602 passes through the clutch line 611 and the brake line 612 branched by the manifold 616 acting as a pressure oil distributor, and the clutch pushing member of the PTO clutch device 70. 75 and the brake pushing member 83 of the PTO brake mechanism 80 (see FIGS. 5 and 9).

The HST line 603 has a pipe 504 connected to the output port 600b (see FIGS. 6 and 13) and a bypass function at the time of clogging, which is supported on the lower outer surface of the front lid portion 62. It communicates with the center section 23 through a line filter 68 (see FIGS. 2, 3 and 6).

FIG. 15 is a front view of the mission case 60 with the center section removed. As shown in FIG. 15, one end side of the mission case front cover 62 is communicated with the HST line 603 through the pipe 504 and the other end side of the line filter 6 is connected.
No. 8, a filter suction line 62a communicating with the suction port 68a, and a filter discharge line 62b having one end communicating with the discharge port 68b of the line filter 68 and the other end opening to the center section supporting surface of the front lid 62. have. The filter discharge line 6
The opening on the other end side of 2b forms the first charge port 23m (see FIGS. 13 and 15). Further, the front lid portion 6
2, the suction line 23 has one end opening to the center section support surface to form a second charge port 23n and the other end opening to the inside of the mission case.
p is formed.

As described above, in the present embodiment,
Since the hydraulic oil is supplied to the HST line 603 through the strainer 66 arranged in the transmission case 60, the line filter 68 can be downsized. That is, when the HST line 603 contains iron powder or the like, it causes a failure of the HST 20 in the subsequent stage, so that it is usually necessary to provide a large-scale line filter with high performance.
On the other hand, in the present embodiment, since the strainer 66 filters the hydraulic oil to some extent as described above, the frequency of replacement of the expensive line filter 68 can be significantly suppressed, and a large filter with such high performance can be provided. There is no need to prepare. Even if the line filter 68 is clogged, the sucked oil bypasses the line filter 68 and flows to the HST 20, so that the HST 20 is not destroyed.

As shown in FIGS. 13 and 14, the center section 23 has a pair of hydraulic lines 23a and 23a 'for hydraulically connecting the hydraulic pump 21 and the hydraulic motor 22 of the HST 20, and the pair of hydraulic lines 23a and 23a'. Hydraulic line 23
First and second bypass lines 23b, 2 connecting between a
3c, a first charge line 23d having one end communicating with the first charge port 23m and the other end communicating with the first bypass line 23b, and one hydraulic line 23a of the first bypass line 23b. Check valve 23e interposed between the connection point of the first bypass line 23b and the connection point of the charge line 23d, and the first bypass line 23b.
Among them, a check valve with a throttle valve 23f inserted between a connection point with the other hydraulic line 23a 'and a connection point with a charge line 23d, and a pair of a check valve with a second bypass line 23c. High pressure relief valve with check valve 23g
And a charge relief valve 23h inserted in the first charge line so as to set the maximum hydraulic pressure of the first charge line 23d, and one end side of the second charge port 2
3n and the other end side is the first charge line 2
The second charge line 23i connected to 3d and the second charge line 23i
A suction check valve 23j inserted in the charge line 23i and a discharge line 23k for discharging the relief oil from the charge relief valve 23h into the HST casing 24 are provided.

Further, in the center section 23,
One end side of the HST is located above the pump shaft 21a.
The inside of the casing 24 is opened, and the other end side is the front lid portion 62.
A drain hole 23l is provided on the contact surface with (see FIG. 9, FIG. 13 and FIG. 14). More specifically, the front lid portion 62 is formed with a communication hole 62c for communicating the drain hole 23l with the front chamber C1 of the mission case 60, and the drain oil discharged into the HST casing 24 is transmitted to the mission. It is designed to flow into the front chamber C1 of the case. Further, an inlet port of the suction check valve 23j, which faces and communicates with the second charge port 23n of the front lid portion 62, is opened in the center section 23 below the motor shaft 22a. .

The second charge line 23i and the suction valve 23j are used for the pair of hydraulic lines 23a, 23a when the vehicle is stopped on a slope while the engine is stopped.
This is to prevent a negative pressure from being generated in a, thereby preventing the vehicle from rolling down a slope (free wheel phenomenon).

As described above, in the power transmission structure according to this embodiment, the pressure oil from the auxiliary pump 420 is supplied to the hydraulic lift device 400, the power steering device, and the HST2.
0, PTO brake mechanism 80 and PTO clutch device 7
In order to reduce the number of parts and reduce the vehicle cost by reducing the number of parts, an additional pump is not required.

Here, the circulation route of the oil stored in the mission case 60 will be described. As described above, the stored oil in the mission case 60 is sucked by the auxiliary pump 420 via the strainer 66 disposed below the middle chamber C2 of the mission case 60. The pressure oil discharged from the auxiliary pump 420 is branched into the first line 412 and the second line 413.

First, the pressure oil branched to the first line 412 acts as hydraulic oil for the hydraulic lift device 400. The return oil from the hydraulic lift device 400 is returned into the rear chamber C3 via the first bulging portion 61c as described above. At this time, in the present embodiment, the interior wall 61
The return oil is cooled by f. The return oil returned to the rear chamber C3 is used for the rear PTO gear train 42 and the mid P
While acting as a lubricating oil for a member housed in the rear chamber C3 such as the TO transmission gear train 43, the TO transmission gear train 43 flows into the middle chamber C2 through the oil communication opening 61y, and is sucked by the auxiliary pump 420 again. To be done.

On the other hand, the pressure oil branched to the second line 413 passes through the optionally provided power steering device and the PTO clutch device 70, and then the HST.
23 is supplied as supplemental hydraulic oil. And the HS
The return oil from T23 is returned to the front chamber C1 of the mission case 60 as described above. The return oil returned to the front chamber C1 is used for the multi-stage transmission device 50 and the PTO clutch device 7
0, front wheel power take-off device 53 and auxiliary pump transmission mechanism 43
0 or the like acting as a lubricant for the storage member in the front chamber C1 and flowing once from the relay chamber C4 to the rear chamber C3 via the oil communication opening 61x, and then the oil communication opening 61x.
It is introduced into the inner chamber C2 via y and is again sucked by the auxiliary pump 420.

As described above, in the present embodiment, H
High-temperature return oil from ST23 or hydraulic lift device 400
As it is, it is prevented from being circulated, which effectively prevents the efficiency of the HST and the efficiency of the hydraulic lift device from being deteriorated.

That is, the HST 23 and the hydraulic lift device 4
The oil returned from 00 becomes high temperature and has low viscosity. Therefore, when the low-viscosity return oil is simply circulated, the auxiliary pump 420, the HST 23 and the hydraulic lift device 400 are
The amount of oil leak increases in each part of the above, and as a result, the pump efficiency of the hydraulic pump, the efficiency of the HST, and / or the efficiency of the hydraulic device deteriorates.

On the other hand, in the present embodiment, the return oils from the HST 23 and the hydraulic lift device 400 are made to flow into the front chamber C1 and the rear chamber C3, respectively, and then returned to the middle chamber C2, It is configured to be circulated again from the middle chamber C2. Therefore, the high temperature return oil is
In the stage of flowing into No. 2, it is sufficiently cooled, thereby preventing the above-mentioned inconvenience due to circulation of high temperature oil.

More preferably, the traveling brake mechanism 210 is housed in the relay chamber C4 provided on the mission case main body 61 and located on one side of the middle chamber C2 in the vehicle width direction, and the relay chamber is also accommodated. The chamber C4 can be configured such that oil can flow in from the front chamber C1 and can escape to the middle chamber C2 (see FIG. 8). This allows
Since oil does not stagnate in the relay chamber C4, the friction heat generated when the traveling brake mechanism 210 is operated can be efficiently released, and the device can be downsized and the durability can be improved. The reference numeral 61z in FIG. 8 is an oil communication opening that connects the front chamber C1 and the relay chamber C4.
Further, reference numeral 62d in FIG. 6 is an oil filling plug screwed into an opening formed in the front lid portion 62. Preferably, the oil filling plug 62d is arranged above the auxiliary pump transmission mechanism 430.

[0128]

According to one aspect of the present invention, a mission case configured to store oil, a PTO system input shaft supported by the case, and a traveling system input shaft supported by the case. A transmission configured to supply pressure oil to the HST and the hydraulic device from a hydraulic pump operatively driven by the PTO system input shaft, the case being provided in order along the vehicle longitudinal direction. A front chamber, a middle chamber, and a rear chamber, which are partitioned by the front support wall and the rear support wall, which have oil-flowable front chambers, middle chambers, and rear chambers.
ST and the return oil from the hydraulic device are respectively introduced into the front chamber and the rear chamber, and the hydraulic pump is configured to suck the oil from the middle chamber, so that the structure is simple, It is possible to effectively prevent the high-temperature return oil from the HST and the hydraulic device from being circulated and supplied to the HST and the hydraulic device again at a high temperature. Therefore, it is possible to effectively prevent the viscosity of the hydraulic oil from being lowered due to the increase in temperature, and prevent the deterioration of the operating efficiency of the hydraulic pump, the HST and / or the hydraulic device.

According to another aspect of the present invention, a hydraulic clutch mechanism for selectively engaging / disengaging the PTO system transmission path, and a rotary member constituting the PTO system transmission path when the power is shut off by the hydraulic clutch mechanism. A PTO system transmission mechanism having a hydraulic brake mechanism for applying a braking force to
In a transmission including a transmission case for accommodating a TO system transmission mechanism, the hydraulic brake mechanism has a proximal end portion slidably accommodated in a cylinder chamber and a distal end portion engaged with a rotating member of the PTO transmission mechanism. And a push member configured to be separated from each other, and the push member is controlled by controlling the pressure oil supply to the cylinder chamber.
The cylinder chamber is formed in the side lid portion of the mission case while the braking force is selectively applied to and released from the O-type transmission mechanism. That is, since the cylinder chamber requiring liquid tightness is formed not on the main body portion of the mission case but on the side lid portion attached to the main body portion, it is necessary to improve the processing accuracy of the main body of the transmission case. The main body portion can be cast relatively easily, and the manufacturing cost of the mission case can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic side view of a vehicle to which a preferred embodiment of a transmission structure according to the present invention is applied.

FIG. 2 is a partially exploded perspective view of an HST and a transmission portion in a preferred embodiment of the transmission structure according to the present invention.

3 is a vertical side view of the HST and transmission shown in FIG.

FIG. 4 is a partial cross-sectional plan view of the HST and transmission shown in FIG.

5 is a cross-sectional view taken along line VV in FIG.

FIG. 6 is a front view of the transmission with a front cover removed.

FIG. 7 is a rear view of the transmission with a rear cover portion removed.

8 is a development view of a drive train of a transmission traveling system taken along line VIII-VIII in FIG.

FIG. 9 is a development view of a transmission PTO system drive train taken along line IX-IX in FIG. 7.

FIG. 10 is a partial cross-sectional plan view in the vicinity of a brake shaft in the transmission. 10 (a) and 10 (b) respectively show a state in which the diff lock device is interlocked when the traveling brake device is activated, and a state in which only the diff lock device is operated independently.

11 is a sectional view taken along line XI-XI in FIG.

FIG. 12 is a hydraulic circuit diagram of a hydraulic lift device and a valve unit portion.

FIG. 13 is a hydraulic circuit diagram of a center section and a PTO clutch device portion.

FIG. 14 is a vertical sectional front view of a center section.

FIG. 15 is a front view of the mission case with the center section removed.

FIG. 16 is a partial cross-sectional plan view of a modification of the transmission.

FIG. 17 is a partial cross-sectional plan view of a modified transmission including a twin pump.

FIG. 18 is a hydraulic circuit diagram of a hydraulic lift device and a valve unit portion when a double pump is provided.

[Explanation of symbols]

10 engine 20 HST 30 transmission 31 PTO system input shaft 32 rear PTO shaft 33 mid PTO shaft 34 traveling system input shaft 41 PTO system transmission shaft 42 rear PTO gear train 43 mid PTO gear train 45 switching device 51 traveling system transmission shaft 52 multistage shifting Device 60 Mission case 61 Mission case body 64 Side lid 61a Front support wall 61b Rear support wall 61f Indoor wall C1 Front chamber C2 of mission case Middle chamber C3 of mission case Rear chamber C4 Mission case brake chamber 70 PTO Clutch device (main PTO gear train) 80 PTO hydraulic brake mechanism 83 Pushing member 85 Cylinder chamber 150 Differential gear device 180 Drive axle 200 Travel brake device 201 Brake shaft 210 Brake mechanism 400 Hydraulic riff 410 valve unit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenichiro Nagata             2-18-1 Inadera, Amagasaki, Hyogo Stock             Company Kanzaki Luxury Machinery Works (72) Inventor Terubu Yoshioka             2-18-1 Inadera, Amagasaki, Hyogo Stock             Company Kanzaki Luxury Machinery Works F term (reference) 3D039 AA04 AA20 AB12 AC40 AC67                 3D042 AA05 AB12 BA02 BA13 BA17                       BA19 BB05 BC06 BC16                 3D043 AA05 AB12 BA06 BA07 BC02                       BC03 BC05 BC07 BC13 BC18                 3J063 AA12 AA14 AB02 AB44 AB56                       AC06 AC14 BA15 CA01 CA04                       CD45 CD46 XH06 XH12 XH22                       XH42

Claims (8)

[Claims] 1. A transmission for a working vehicle provided with a working device which is moved up and down by a hydraulic device, comprising a transmission case configured to store oil, and a PTO system input shaft supported by the case. And a PTO system input shaft operatively receiving a driving force from the engine and operatively connected to the hydraulic pump, and a traveling system input shaft supported by the case, wherein the driving force from the engine is received. A traveling system input shaft operatively received via an HST and operatively connected to a drive axle, wherein the hydraulic pump is configured to supply pressure oil to the HST and the hydraulic device; The case is a front chamber, a middle chamber, and a rear chamber that are partitioned by a front support wall and a rear support wall that are sequentially provided in the vehicle front-rear direction, and the front chamber, the middle chamber, and the rear chamber that allow oil to flow between them. Have a room The return oils from the HST and the hydraulic device are introduced into the front chamber and the rear chamber, respectively, and the hydraulic pump is configured to suck the oil from the middle chamber. Transmission for work vehicles. 2. The power transmission from the PTO system input shaft is turned on / off in the front chamber on the downstream side of the power transmission of the hydraulic pump.
A PTO clutch that is turned off is accommodated, a drive train for driving a PTO shaft is accommodated in the rear chamber, and the front chamber and the rear chamber are PTO transmission shafts that connect the PTO clutch and the drive train. The communication is carried out through a housed relay room.
The work vehicle transmission described in. 3. A brake shaft arranged in a front stage of the drive axle in the transmission direction, and a brake mechanism for applying a braking force to the brake shaft, the brake shaft and the brake mechanism being The work vehicle transmission according to claim 2, wherein the relay chamber is housed in a relay chamber, and the relay chamber is configured such that oil can flow in from the front chamber and flow out to the middle chamber. 4. The work vehicle transmission according to claim 1, wherein the rear chamber is provided with an inner wall for temporarily receiving return oil from the hydraulic device. . 5. A multi-stage transmission that further shifts the driving force input to the traveling system input shaft in multiple stages and operatively transmits it to the drive axle, wherein the multi-stage transmission is housed in the front chamber. The work vehicle transmission according to any one of claims 1 to 4, wherein an input end portion of the drive axle is housed in the middle chamber. 6. A mission case having a main body part having an opening at least on one side in the vehicle width direction and a side lid part closing the opening of the main body part, and a mission case supported by the case and operatively connected to an engine. A PTO input shaft and a P supported by the case so as to be output to the outside of the case.
A work vehicle transmission having a TO shaft and a PTO system transmission mechanism that forms a power transmission path from the PTO system input shaft to the PTO shaft, wherein the PTO system transmission mechanism is provided from the PTO system input shaft. A hydraulic clutch mechanism capable of selectively interrupting a power transmission path to the PTO shaft; and a hydraulic brake mechanism applying a braking force to a rotating member of the PTO system transmission mechanism when the power transmission path of the hydraulic clutch mechanism is interrupted. The hydraulic brake mechanism is configured such that the base end portion is slidably housed in the cylinder chamber and the tip end portion is engaged / separated with the rotating member of the PTO system transmission mechanism. Has a pushing member, and the pushing member selectively applies and releases a braking force to the PTO system transmission mechanism by controlling the pressure oil supply to the cylinder chamber. So that is configured to, the cylinder chamber, the working vehicle transmissions, characterized in that formed on the side cover portion of the transmission case. 7. The hydraulic clutch mechanism and the hydraulic brake mechanism are configured to be operated by hydraulic oil supplied from a common hydraulic source, and the side lid portion includes the hydraulic clutch mechanism and the hydraulic brake. The hydraulic oil control member for controlling the supply of hydraulic oil to the mechanism, and the pressure oil distributor for distributing the hydraulic oil to each of the hydraulic clutch mechanism and the hydraulic brake mechanism are provided. Work vehicle transmission. 8. The work vehicle transmission according to claim 7, wherein the hydraulic oil control member and the pressure oil distributor are detachably attached to an outer side and an inner side of the side lid portion, respectively. .