JP2008201284A - Transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve attaching-detaching workability of a switching valve, while preventing contact with an external part of the switching valve, without complicating a structure of a pair of main frames connected to a transmission case, in a transmission for a work vehicle having the transmission case separately arranged on the other side in the longitudinal direction of a vehicle from a driving source, an HST supported by a first end wall on one side in the longitudinal direction of the vehicle in the transmission case, a hydraulic transmission unit stored in the transmission case and the switching valve for switching a transmission state of the hydraulic transmission unit. <P>SOLUTION: The switching valve is directly or indirectly detachably constituted from one side in the longitudinal direction of the vehicle on the first end wall of turning to one side in the longitudinal direction of the vehicle of the transmission case. For example, when having a traveling system auxiliary output shaft supported by the transmission case so as to be outputted toward an auxiliary driving wheel on one side in the longitudinal direction of the vehicle, the switching valve is installed in an area displaced in the vehicle width direction to the traveling system auxiliary output shaft under the HST. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transmission applied to a work vehicle such as a tractor.

  A pair of main frames extending in the longitudinal direction of the vehicle; a drive source supported at the front of the main frame; a mission case supported at the rear of the main frame; and an HST supported at the front of the mission case; A hydraulic PTO clutch unit housed in the transmission case, and a traveling system auxiliary output shaft supported on the front surface of the transmission case so as to output rotational power toward the front wheels acting as auxiliary driving wheels. There has been proposed a working vehicle configured to ensure a free space between the drive source and the transmission case (see, for example, Patent Document 1 below).

Incidentally, the hydraulic PTO clutch unit is configured such that the transmission state is switched by hydraulic oil supply / discharge control by a PTO valve.
However, Patent Document 1 does not describe how to install the PTO valve.

Further, in Patent Document 2 below, in a transmission including a transmission case and a hydraulic F / R switching unit for switching the rotation direction of a driving wheel to a forward direction or a backward direction, transmission of the F / R switching unit is described. A configuration in which an F / R valve for switching the state is mounted on the side wall of the mission case is described.
Thus, when the PTO valve is mounted on the side wall of the transmission case, the PTO valve protrudes outward from the transmission case in the vehicle width direction. Therefore, the PTO valve may come into contact with an external object and be damaged.
In the configuration in which the PTO valve is mounted on the side wall of the transmission case, the PTO valve can be covered by the pair of main frames. In this configuration, the spacing between the pair of main frames is Must be increased, leading to an increase in vehicle width. Furthermore, when the PTO valve is attached to and detached from the transmission case, there is a problem that the pair of main frames become an obstacle.
Japanese Patent No. 3636594 Japanese Patent No. 3688752

  The present invention has been made in view of the above-described prior art, and the vehicle longitudinal direction from a drive source that is directly or indirectly supported on one side of the vehicle longitudinal direction of a pair of left and right main frames arranged along the vehicle longitudinal direction. A transmission case connected to the other side of the pair of main frames in the vehicle longitudinal direction in a state of being separated to the other side, an HST supported by a first end wall on the vehicle longitudinal direction side of the transmission case; A transmission for a working vehicle including a hydraulic transmission unit housed in a case and a switching valve that switches a transmission state of the hydraulic transmission unit, without causing an increase in the separation width of the pair of main frames, To provide a transmission with a simple structure capable of effectively preventing the switching valve from being damaged by contact with an external object. For the purpose.

  In order to achieve the above object, the present invention provides a drive source that is directly or indirectly supported on one side in the vehicle front-rear direction of a pair of left and right mainframes arranged along the vehicle front-rear direction, to the other side in the vehicle front-rear direction. A mission case connected to the other side of the pair of main frames in the vehicle longitudinal direction in a separated state, an HST supported on the first end wall on one side of the mission case in the vehicle longitudinal direction, and the mission case A transmission for a working vehicle comprising a housed hydraulic transmission unit and a switching valve for switching a transmission state of the hydraulic transmission unit, wherein the switching valve is directly or indirectly on the first end wall of the transmission case. A transmission that can be detached from one side in the vehicle longitudinal direction is provided.

  In an aspect including a traveling system auxiliary output shaft supported by the transmission case so as to output toward the auxiliary driving wheel on one side in the vehicle longitudinal direction, preferably, the switching valve is below the HST and the traveling It is mounted in a region displaced in the vehicle width direction with respect to the system auxiliary output shaft.

The hydraulic transmission unit is disposed on the rear side in the longitudinal direction of the vehicle from the drive source, and a hydraulic PTO clutch unit that selectively engages or shuts off a PTO transmission path that transmits rotational power from the drive source to the PTO shaft. In the case of including a traveling system hydraulic switching unit that switches the transmission state of the traveling system main transmission path to the main driving wheel, and a hydraulic auxiliary driving wheel switching unit that switches the transmission state to the auxiliary driving wheel, for example, The PTO clutch unit is disposed on one side in the vehicle width direction with respect to the traveling system auxiliary output shaft, and the traveling system hydraulic switching unit is disposed on the other side in the vehicle width direction with reference to the traveling system auxiliary output shaft. Is done.
In such an aspect, the switching valve includes a PTO switching valve that switches a transmission state of the PTO clutch unit, a traveling system switching valve that switches a transmission state of the traveling system hydraulic switching unit, and the auxiliary drive wheel switching unit. And a sub-drive wheel switching valve for switching the transmission state. The PTO switching valve, the traveling system switching valve, and the auxiliary drive wheel switching valve are arranged in a vehicle width direction with the auxiliary output shaft interposed therebetween.

Preferably, an oil passage block that is detachably attached to the first end wall of the mission case may be provided.
The oil passage block includes first and second recesses that are provided on both sides of the auxiliary output shaft in the vehicle width direction so as to open to one side in the vehicle front-rear direction, and are detachably mounted. First and second recesses that cooperate with the members to form liquid-tight first and second closed spaces, a supply oil passage that supplies hydraulic oil from a hydraulic source to the first and second closed spaces, A supply / discharge oil passage for traveling whose one end is opened in the first closed space, a supply / discharge oil passage for PTO whose one end is opened in the first closed space, and one end of the second closed space. A sub-drive wheel oil supply / discharge oil passage opened in the inside, a first drain oil passage whose one end is opened in the first closed space, and a second drain whose one end is opened in the second closed space. And an oil passage.
The traveling system switching valve is accommodated in the first closed space so as to selectively fluidly connect the traveling supply / discharge oil passage to the supply oil passage or the first closed space. The PTO switching valve is accommodated in the first closed space so as to selectively fluidly connect the PTO supply / discharge oil passage to the supply oil passage or the first closed space. The auxiliary drive wheel switching valve is accommodated in the second closed space so as to selectively fluidly connect the auxiliary drive wheel supply / discharge oil passage to the supply oil passage or the second closed space.

More preferably, the oil passage block may include a block main body in which the first and second recesses are formed, and a plate that comes into contact with an end surface of the block main body on the other side in the vehicle front-rear direction.
The end surface of the block body on the other side in the vehicle front-rear direction cooperates with the plate to supply the supply oil passage, the travel supply / discharge oil passage, the PTO supply / discharge oil passage, and the auxiliary drive wheel supply / discharge oil. A plurality of oil grooves that respectively form the paths are formed.

  As described above, the present invention provides a transmission case that is spaced apart from the drive source on the other side in the vehicle longitudinal direction, an HST that is supported on the first end wall on the vehicle longitudinal direction side in the mission case, and the mission case. In a transmission for a working vehicle including a hydraulic transmission unit housed in a hydraulic power transmission unit and a switching valve for switching a transmission state of the hydraulic power transmission unit, the switching valve is directly or indirectly on the first end wall of the transmission case. Since the pair of main frames connecting the drive source and the transmission case is not complicated, the switching valve is in contact with an external object and is damaged. Can be effectively prevented, and the switching valve can be easily attached and detached.

Hereinafter, preferred embodiments of a transmission according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows a side view of a working vehicle 1 to which a transmission 100 according to the present embodiment is applied. FIG. 2 shows a schematic diagram of transmission of the working vehicle 1.

As shown in FIGS. 1 and 2, the work vehicle 1 is a tractor to which a work machine can be attached.
Specifically, the working vehicle 1 is supported by a vehicle frame 5 including a pair of main frames 6 extending in the longitudinal direction of the vehicle, and one end side (front side in the illustrated embodiment) of the pair of main frames 6 in the longitudinal direction of the vehicle. A driving source 10 (see FIG. 2) is supported on the other end side in the vehicle longitudinal direction of the pair of main frames 6 (the rear side in the illustrated embodiment) at a position spaced apart from the driving source 10 in the vehicle longitudinal direction. The transmission 100 is provided.

The transmission 100 is a travel system transmission path that transmits power input from the drive source 10 via the transmission shaft 15 (see FIG. 2) to the drive wheels (in the form shown, after acting as a main drive wheel). A driving system main transmission path for transmitting power to the wheels 30 and a driving system sub transmission path for transmitting power to the front wheels 35 acting as auxiliary driving wheels), and the power from the drive source 10 is output to the outside. And a PTO transmission path.
In the present embodiment, as shown in FIG. 2, a flywheel unit 11 and a transmission unit 12 are connected to the drive source 10, and the drive source 10, the flywheel unit 11, and the transmission unit are connected. 12 forms a drive source unit 10A.
That is, in the present embodiment, the power from the drive source 10 is transmitted to the transmission 100 via the flywheel unit 11, the transmission unit 12, and the transmission shaft 15.

3 and 4 show a front view and a plan view of the transmission 100, respectively.
5 and 6 are a perspective view and an exploded perspective view of the transmission 100, respectively.
As shown in FIGS. 2 to 6, the transmission 100 is connected to the other side of the pair of main frames 6 in the vehicle front-rear direction while being separated from the drive source 10 to the other side of the vehicle front-rear direction. The planetary gear unit 150 accommodated in the mission case 200 so as to input constant speed power from the drive source 10 and variable speed power from the HST 110; A traveling system hydraulic switching unit 300 accommodated in the mission case 200 in a state of being operatively connected to the planetary gear unit 150, and rotational power from the traveling system hydraulic switching unit 300 are differentially transmitted to a pair of main drive axles. Main differential gear housed in the mission case 200 so as to transmit A unit 400, a hydraulic PTO clutch unit 500 accommodated in the transmission case 200 in a state where constant speed power from the drive source 10 can be input, and a state in which the unit 400 is operatively connected to the driven side of the PTO clutch unit 500 The PTO multi-stage transmission unit 550 accommodated in the transmission case 200 and the PTO shaft 260 operatively connected to the PTO multi-stage transmission unit 550, the HST 110, the planetary gear unit 150, and the main differential gear. The unit 400 forms the traveling system main transmission path, and the PTO clutch unit 500 and the PTO multi-stage transmission unit 550 form the PTO system transmission path.

In the present embodiment, as shown in FIG. 2, the transmission 100 further supports the traveling system auxiliary output supported by the transmission case 200 so as to output rotational power toward the auxiliary driving wheel 35. A shaft 450, and a hydraulic sub-drive wheel switching unit 410 housed in the transmission case 200 so as to be inserted into a transmission path from the traveling system hydraulic switching unit 300 to the traveling system secondary output shaft 450. I have.
The travel system sub output shaft 450 and the sub drive wheel switching unit 410 form the travel system sub transmission path for transmitting rotational power to the sub drive wheel 35.
As shown in FIG. 2, the traveling system secondary output shaft 450 operates via a transmission shaft 460 to a secondary differential gear unit 470 in a front axle case that is spaced from the transmission case 200 to one side in the vehicle longitudinal direction. It is connected.

7 to 9 show a longitudinal side view, an exploded longitudinal perspective view, and a rear perspective view of the mission case, respectively.
The transmission case 200 accommodates the various transmission units and can store oil.

As shown in FIGS. 7 to 9, the transmission case 200 includes a peripheral wall 200c extending in the vehicle front-rear direction, and a first end wall 200a extending in a substantially vertical direction at one end of the peripheral wall 200c in the vehicle front-rear direction. A second end wall 200b extending in a substantially vertical direction at the end of the peripheral wall 200c on the other side in the vehicle front-rear direction and a first vertical wall extending between the first and second end walls 200a, 200b in the vehicle front-rear direction. A first intermediate wall 201a and a second intermediate wall 201b extending in a substantially vertical direction between the first intermediate wall 201a and the second end wall 200b in the vehicle longitudinal direction, and the first end wall 200a and A first space 210A is formed between the first intermediate walls 201a, and a second space 210B is formed between the first intermediate wall 201a and the second intermediate wall 201b. It is.
In the present embodiment, the mission case 200 further includes a third intermediate wall 201c that extends substantially perpendicularly between the second intermediate wall 201b and the second end wall 200b. A second space 210C is formed between the second intermediate wall 201b and the third intermediate wall 201c, and a fourth space 210D is formed between the third intermediate wall 201c and the second end wall 200b.

  In the present embodiment, the mission case 200 includes a hollow mission case body 220 having first and second openings 221 and 222 on one side and the other side in the vehicle front-rear direction, and a hollow portion of the mission case body 220. A bearing plate 225 that is detachably connected to the transmission case main body 220 so as to be positioned at a position, and a first cover member 230 that is detachably connected to the transmission case main body 220 so as to close the first opening 221. And a second cover member 235 detachably coupled to the transmission case main body 220 so as to close the second opening 222.

As shown in FIGS. 7 and 8, the mission case main body 220 is integrally provided with the second and third intermediate walls 201b and 201c.
As shown in FIG. 8, the bearing plate 225 can be disposed in the hollow portion of the mission case main body 220 through the first opening 221 and is connected to a rib provided on the mission case main body 220. Thus, the first intermediate wall 201a is formed.

As shown in FIGS. 7 and 8, the first cover member 230 has an end wall 231 that forms the first end wall 200a and a peripheral wall 232 that extends from the periphery of the end wall 231 to the vehicle rear side. The free end of the peripheral wall 232 is connected to the end surface of the transmission case main body 220 on one side in the vehicle front-rear direction.
The second cover member 235 has a plate shape that forms the second end wall 200b, and is connected to the other end surface of the transmission case main body 220 in the vehicle front-rear direction.

As shown in FIGS. 5 and 6, the HST 110 is supported by the first end wall 200 a of the mission case 200.
Specifically, as shown in FIGS. 2 to 6, the HST 110 includes an HST input shaft 111 operatively connected to the drive source 10 and a hydraulic pump main body 112 (non-rotatably supported by the HST input shaft 111 ( 2), a hydraulic motor main body 114 (see FIG. 2) fluidly connected to the hydraulic pump main body 112, an HST output shaft 113 that supports the hydraulic motor main body 114 in a relatively non-rotatable manner, and the hydraulic pump main body 112. And an HST case 115 that houses the hydraulic motor main body 114 and supports the HST input shaft 111 and the HST output shaft 113 so as to be rotatable about an axis.

At least one of the hydraulic pump main body 112 and the hydraulic motor main body 114 is a variable displacement type.
In the present embodiment, as shown in FIG. 2, the hydraulic pump main body 112 is a variable displacement type.
Therefore, as shown in FIG. 2, the HST 110 includes an output adjustment including a movable swash plate that changes the amount of oil supplied to and discharged from the hydraulic pump main body 112 and a control shaft that tilts the movable swash plate in addition to the above configuration. A member 120 is provided.
The control shaft extends in a direction orthogonal to the HST input shaft 111 and is supported by the HST case 115 so as to be rotatable about an axis line with one end portion extended outward.
The movable swash plate is housed in the HST case 115 in a state of being connected to the other end of the control shaft via a connecting arm, and tilts in response to rotation around the axis of the control shaft. It has become.

In the present embodiment, the control shaft is rotated about its axis by a hydraulic servo mechanism 125 operated in accordance with the operation of an operation member such as a shift lever.
FIG. 10 shows a hydraulic circuit diagram of the working vehicle 1.
As shown in FIG. 10, in the present embodiment, the HST 110 includes a hydraulic servo mechanism 125 that operates the output adjustment member 120.

As shown in FIGS. 4 to 6, the HST case 115 includes a case main body 116 and a port block 117 that is detachably connected to the case main body 116.
The case main body 116 is shaped to surround the hydraulic pump main body 112 and the hydraulic motor main body 114, and is an opening through which both the units 112 and 114 can be inserted on one side in the axial direction of the HST input shaft 111. Is provided.
The port block 117 is connected to the case body 116 so as to close the opening.

The port block 117 is supplied with hydraulic oil to the pair of HST lines 700 and a pair of HST oil passages 701 forming the following pair of HST lines 700 for fluidly connecting the hydraulic pump body 112 and the hydraulic motor body 114. For this purpose, a charge oil passage 706 that forms part of the following charge line 705 is formed (see FIG. 10).
Note that reference numeral 605 in FIG. 10 is a check valve that allows inflow of hydraulic oil from the charge line 705 to the corresponding hydraulic oil passage 701 and prevents reverse flow, and reference numeral 606 indicates the pair of HST oils. This is a high-pressure relief valve for preventing the passage 701 from becoming an abnormally high pressure.

  As shown in FIGS. 5 and 6, etc., the HST case 115 is arranged so that the HST input shaft 111 and the HST output shaft 113 are arranged in parallel in the vehicle width direction in a state along the vehicle longitudinal direction. The first end wall 200a of the 200 is supported directly or indirectly.

Specifically, the HST input shaft 111 extends from the drive source 10 to the other side in the vehicle longitudinal direction and extends from the other end to the vehicle longitudinal direction so that one end can be operatively connected to the drive source 10. The HST case 115 is supported in a state where constant speed power can be output.
The HST output shaft 113 is supported by the HST case 115 so as to be able to output speed change power by the HST 110 from the other end portion in the vehicle longitudinal direction.
As shown in FIG. 3, the HST case 115 is arranged such that the HST input shaft 111 and the HST output shaft 113 are juxtaposed in the vehicle width direction at substantially the same height above the traveling system sub output shaft 450. Further, the transmission case 200 is supported by the first end wall 200a.

In the present embodiment, as shown in FIGS. 3 to 5, the hydraulic servo mechanism 125 is disposed on the opposite side of the vehicle width direction from the HST output shaft 113 with respect to the HST input shaft 111. This prevents the HST 110 from increasing in size in the vertical direction.
In other words, in the present embodiment, the HST input shaft 111 is positioned substantially in the center in the vehicle width direction, and the hydraulic servo mechanism 125 and the HST output shaft 113 are in the vehicle width direction with reference to the HST input shaft 111. Arranged on one side and the other side.

  As shown in FIG. 2, the planetary gear unit 150 transmits constant speed power via the HST input shaft 111 or a constant speed output shaft 251 that is coaxially connected to the HST input shaft 111 and connected to the HST input shaft 111 so as not to rotate relative to the axis. The HST output shaft 113 in a state in which variable speed power can be input via the HST output shaft 113 or the shift output shaft 252 that is coaxially connected to the HST output shaft 113 and is not rotatable relative to the axis. Are accommodated in the first space 210A so as to be coaxial with each other.

11 and 12 show a front view and a plan view of the transmission 100 with the first cover member 230 removed, respectively.
FIG. 13 is a plan view of a transmission mechanism including a transmission unit and a transmission shaft housed in the transmission case. In FIG. 13, the mission case 200 is schematically indicated by a two-dot chain line.
Further, FIGS. 14 and 15 are a perspective view of the transmission mechanism with the transmission case 200 omitted from one side in the vehicle longitudinal direction and one side in the vehicle width direction and one transmission mechanism in the vehicle longitudinal direction, respectively. The perspective view seen from the side and the vehicle width direction other side is shown.
FIG. 16 is a front view of the transmission mechanism with the transmission case omitted.

  As shown in FIGS. 2 and 11 to 16, the transmission 100 is coaxial with the HST input shaft 111 and is connected to the HST input shaft 111 so as not to rotate relative to the HST input shaft 111. The constant speed output shaft 251 supported by the first intermediate wall 201a, the constant speed gear 271 supported by the constant speed output shaft 251 so as not to rotate relative to the first intermediate wall 201a, and the HST output shaft 113 coaxially around the axis. The shift output shaft 252 supported by the first end wall 200a and the first intermediate wall 201a so as to be connected so as not to be relatively rotatable.

  In such a configuration, as shown in FIGS. 2 and 11 to 16, the planetary gear unit 150 is supported by the speed change output shaft 252 so as not to rotate relative to the axis, and receives speed change power input by the HST 110. A sun gear 151 acting as a member, a gear meshing with the constant speed gear 271 on the outer peripheral surface, and an internal gear 152 acting as a constant speed power input member for inputting constant speed power from the drive source 10; The planetary gear 153 meshing with the internal gears of the sun gear 151 and the internal gear 152 and the revolution component of the planetary gear 153 around the sun gear 151 are extracted, and the combined output for outputting the combined rotation of the speed change power and the constant speed power Member 154.

As shown in FIGS. 12 and 13, the composite output member 154 is disposed on one side in the vehicle longitudinal direction from the constant speed gear 271.
That is, in the present embodiment, the constant speed gear 271 is disposed on the other side in the vehicle front-rear direction in the first space 210A.
The internal gear 152 is disposed at substantially the same position as the constant speed gear 271 with respect to the vehicle longitudinal direction position, and the composite output member 154 is disposed on the vehicle longitudinal direction one side from the internal gear 152. .

The composite output member 154 is operatively connected to a traveling system transmission shaft 253 disposed below the HST output shaft 113 (or the transmission output shaft 252), as shown in FIGS. .
In other words, in the present embodiment, the transmission 100 further includes the traveling system transmission shaft 253 that transmits the combined output from the planetary gear unit 150 to the traveling system hydraulic switching unit 300 that follows.

As shown in FIG. 15, the traveling transmission shaft 253 has one end on one side in the vehicle front-rear direction positioned in the first space 210A, and the other end on the other side in the vehicle front-rear direction is the second space. The first end wall 200a, the first intermediate wall 201a, and the second intermediate wall 201b are supported along the vehicle front-rear direction so as to be positioned in 210B.
A synthetic input gear 272 that is operatively connected to the synthetic output member 154 is supported on the portion of the traveling system transmission shaft 253 located in the first space 210 </ b> A so as not to be relatively rotatable.

The traveling system hydraulic switching unit 300 is provided for switching the transmission state from the traveling system transmission shaft 253 to the main differential gear unit 400.
As shown in FIG. 2, the transmission 100 according to the present embodiment includes a hydraulic F / R switching unit 310 that switches the transmission direction to drive wheels as the traveling system hydraulic switching unit 300.

As shown in FIGS. 13 and 15, the F / R switching unit 310 is accommodated in the second space 210B.
Specifically, as shown in FIGS. 2 and 15, the F / R switching unit 310 is an F / R supported so as not to rotate relative to a portion of the traveling transmission shaft 253 located in the second space 210 </ b> B. A reverse drive member 312R and a forward drive member that are rotatably supported by the travel transmission shaft 253 in a state where the housing 311 and the partition wall 311a of the F / R housing 311 are arranged in the longitudinal direction of the vehicle. 312F, a reverse-side friction plate group 315R (see FIG. 10) for selectively engaging or releasing the power transmission from the F / R housing 311 to the reverse-side drive member 312R by the action of hydraulic pressure, and the above-mentioned by the action of hydraulic pressure A forward friction plate group 315F (see FIG. 10) for selectively engaging or releasing the power transmission from the F / R housing 311 to the forward drive member 312F. ) And comprises a forward side driving gear 313F relatively non-rotatably supported on the forward side driving member 312F, the rearward-travel driving gear 313R which are relatively non-rotatably supported on the reverse side driving member 312R.

As shown in FIG. 2, the F / R housing 311 has a base end portion that is supported by the traveling system transmission shaft 253 so as not to rotate relative to the traveling system transmission shaft 253, and a distal end portion that extends radially outward from the traveling system transmission shaft 253. It has a partition wall 311a and a peripheral wall 311b extending from the tip of the partition wall 311a to one side and the other side in the vehicle longitudinal direction.
The reverse drive member 312R and the forward drive member 312F are supported by the travel system transmission shaft 253 so as to be relatively rotatable with the partition wall 311a interposed therebetween on one side and the other side in the vehicle front-rear direction. ing.
In the present embodiment, as shown in FIGS. 2 and 15, the reverse drive member 312R is disposed on one side in the vehicle longitudinal direction from the partition wall 311a, and the forward drive member 312F is from the partition wall 311a. It is arranged on the other side in the vehicle longitudinal direction.

The forward drive member 312F and the reverse drive member 312R are operatively connected to the main differential gear unit 400.
In the present embodiment, as shown in FIGS. 2 and 15 and the like, the transmission 100 has the second space 210B above the traveling system transmission shaft 253 so as to be substantially parallel to the traveling system transmission shaft 253. The forward drive member 312F and the reverse drive member 312R are operatively connected to the main differential gear unit 400 via the main drive wheel output shaft 254. Has been.

The main drive wheel output shaft 254 is supported along the vehicle longitudinal direction so that the other end of the vehicle longitudinal direction is operatively connected to the ring gear 401 of the main differential gear unit 400.
Specifically, the main differential gear unit 400 is accommodated in the third space 210C as shown in FIGS. Accordingly, the main drive wheel output shaft 254 is arranged along the vehicle front-rear direction by the first intermediate wall 201a and the second intermediate wall 201b with the other end in the vehicle front-rear direction protruding into the third space 210C. It is supported.
In the present embodiment, the main drive wheel output shaft 254 is disposed coaxially with the HST output shaft 113 (and the transmission output shaft 252) (see FIG. 15 and the like).

A forward driven gear 314F and a reverse driven gear 314R that are operatively engaged with the forward drive gear 313F and the reverse drive gear 313R, respectively, are supported on the main drive wheel output shaft 254 so as not to be relatively rotatable. .
In the present embodiment, as shown in FIG. 2, the forward driven gear 314F is directly meshed with the forward drive gear 313F.
On the other hand, as shown in FIGS. 2 and 15, the reverse drive gear 314 </ b> R is connected to the reverse drive side via a transmission gear 273 supported by the following sub drive wheel transmission shaft 255 that forms the travel system sub transmission path. It is meshed with the drive gear 313R.

Here, first, a transmission path when the working vehicle 1 moves forward will be described.
The transmission 100 according to the present embodiment is configured to be able to perform two-stage shift between the forward drive member 312F and the main drive wheel output shaft 254.
Specifically, as shown in FIG. 2, the transmission 100 includes two traveling system drives including a forward drive high speed gear 313F (H) and a forward drive low speed gear 313F (L) acting as the forward drive gear 313F. A side transmission gear, two traveling system driven gears including a forward driven low speed gear 314F (H) and a forward driven low speed gear 314F (L) acting as the forward driven gear 314F, and the two traveling systems And a traveling transmission gear shifter 355 for selectively engaging the driven transmission gears 314F (H) and 314F (L) with the main drive wheel output shaft 254.
The two traveling system drive side transmission gears 313F (H) and 313F (L), the two traveling system driven side transmission gears 314F (H) and 314F (L), and the traveling system transmission shifter 355 move forward. A side travel system multi-stage transmission unit 350 (see FIG. 2 and the like) is configured.

FIG. 17 is a longitudinal front view of the transmission mechanism as viewed from the other end surface of the first intermediate wall 201a on the other side in the vehicle front-rear direction.
The traveling multi-stage transmission unit 350 is operated via a traveling transmission operation mechanism 360 provided in the transmission 100.
As shown in FIGS. 13, 15, and 17, the traveling system shift operation mechanism 360 includes a traveling system shift fork 361 whose front end is engaged with the traveling system shift shifter 355, and a longitudinal axis along the vehicle longitudinal direction. A travel system fork shaft 362 supported by the first intermediate wall 201a and the second intermediate wall 201b so as to be movable in the direction, and a travel system fork shaft 362 that supports a base end side of the travel system shift fork 361. A traveling system operation shaft 363 that is supported by the mission case 200 so as to be rotatable about the axis line along the vehicle width direction above the traveling system fork shaft 362, and a base end portion is supported by the traveling system operation shaft 363. In addition, an operating arm 364 is engaged at the tip end portion with the traveling system fork shaft 362.

The traveling system shift operation mechanism 360 operates as follows.
When an operating member such as a travel system multi-stage shift lever provided near the driver's seat is operated, the travel system operation shaft 363 rotates around the axis. The rotation of the traveling system operation shaft 363 about the axis moves the traveling system fork shaft 362 engaged with the operation arm 364 in the axial direction, and the traveling system shift shifter 355 causes the two traveling system driven side shifts. The gears 314F (H) and 314F (L) are selectively engaged with the main drive wheel output shaft 254.
In the present embodiment, as described above, it is configured so that a two-speed shift can be performed between the forward drive member 312F and the main drive wheel output shaft 254. It is also possible to configure so that the speed change can be performed.

Next, a transmission path when the working vehicle 1 moves backward will be described.
As described above, the reverse drive gear 313R is meshed with the reverse drive gear 314R via the transmission gear 273 supported by the auxiliary drive wheel transmission shaft 255.
That is, in the present embodiment, the transmission gear 273 forms the traveling system sub-transmission path and also forms the traveling system main transmission path during reverse travel.

Specifically, the transmission 100 includes the sub drive wheel transmission shaft 255 that forms a part of the traveling system sub transmission path, as shown in FIGS. 2, 11, 15 to 17, and the like.
The auxiliary drive wheel transmission shaft 255 is supported by the first end wall 200a and the first intermediate wall 201a so as to be rotatable about the axis, with the other end in the vehicle longitudinal direction protruding into the second space 210B. .
As shown in FIGS. 15 and 17, the transmission gear 273 is supported by the portion of the auxiliary drive wheel transmission shaft 255 located in the second space 210 </ b> B so as not to be relatively rotatable.

  Thus, in the present embodiment, the transmission gear 273 that forms a part of the traveling system sub-transmission path is configured to form a part of the traveling system main transmission path during reverse travel. Thus, the transmission 100 can be downsized in the vehicle front-rear direction.

  Further, in the present embodiment, as shown in FIG. 17 and the like, the auxiliary drive wheel transmission shaft 255 is disposed between the main drive wheel output shaft 254 and the traveling system transmission shaft 253 in the vertical direction, and in the vehicle. With respect to the width direction, the main drive wheel output shaft 254 and the traveling system transmission shaft 253 are located on one side in the vehicle width direction (the side close to the HST input shaft 111 or the constant speed output shaft 251). The transmission 100 is downsized.

Specifically, in the present embodiment, as shown in FIGS. 11, 15, 17 and the like, the main drive wheel output shaft 254 is arranged coaxially with the HST output shaft 113 (or the transmission output shaft 252). The traveling system transmission shaft 253 is disposed at substantially the same position as the shift output shaft 252 in the vehicle width direction and below the shift output shaft 252. The auxiliary drive wheel transmission shaft 255 is located between the shift output shaft 252 and the travel transmission shaft 253 in the vertical direction, and the HST input shaft 111 (the constant speed output shaft 251) and the vehicle width direction. It is disposed between the HST output shaft 113 (the shift output shaft 252).
According to such a configuration, the traveling drive shaft 253, the auxiliary drive wheel drive shaft 255, and the main drive are engaged with the reverse drive gear 313R meshed with the reverse drive gear 314R via the transmission gear 273. The wheel output shaft 254 can be disposed as close as possible, whereby the transmission 100 can be reduced in size.

As described above, in the transmission 100 according to the present embodiment, the planetary gear unit 150 is accommodated in the first space 210A defined by the first end wall 200a and the first intermediate wall 201a, and the traveling The system hydraulic switching unit 300 is accommodated in a second space 210B defined by the first intermediate wall 201a and the second intermediate wall 201b, and the differential gear unit 400 is arranged in front of and behind the vehicle from the second intermediate wall 201b. It is accommodated in the third space 210C located on the other side in the direction.
According to such a configuration, it is possible to improve the work efficiency of assembling the planetary gear unit 150 and the traveling system hydraulic switching unit 300 to the mission case 200, and it is possible to easily change the vehicle specifications. it can.

That is, in the conventional configuration in which the planetary gear unit and the traveling system hydraulic switching unit are accommodated in the same space of the transmission case, the two units cannot be assembled independently in the transmission case. Assembling work efficiency is worsened.
Further, depending on the specifications, an F / R switching unit or an H / L switching unit may be used as the traveling system hydraulic switching unit. In the conventional configuration, the planetary gear unit and the traveling unit may be used. Since the hydraulic switching unit is accommodated in the same space, it is difficult to cope with such a change in specifications.

On the other hand, in the present embodiment, as described above, the planetary gear unit 150 is accommodated in the first space 210A, and the traveling system hydraulic switching unit 300 is accommodated in the second space 210B. Yes. Therefore, these units can be independently assembled to the mission case 200, and the assembly work efficiency can be improved.
Furthermore, in the present embodiment, the traveling system hydraulic switching unit 300 is housed in the second space 210B partitioned from the first space 210A in which the planetary gear unit 150 is housed. The specifications of the traveling system hydraulic switching unit 300 can be easily changed.

Further, by accommodating the planetary gear unit 150 and the traveling system hydraulic switching unit 300 in a space partitioned from each other, the planetary gear unit 150 and the traveling system hydraulic switching unit 300 are prevented from interfering with each other. However, the distance between the HST output shaft 113 (the transmission output shaft 252) and the traveling system transmission shaft 253 can be reduced, and the transmission 100 can be reduced in size.
In the present embodiment, as shown in FIG. 16, the transmission output shaft 252 and the traveling transmission shaft 253 are partially overlapped with the planetary gear unit 150 and the F / R switching unit 310 in a front view. To be close to each other.

  In the present embodiment, the first intermediate wall 201a is formed by the bearing plate 225 that is detachably coupled to the mission case body 220. Accordingly, the traveling system hydraulic switching unit 300 is assembled in the second space 210B, and then the bearing plate 225 is attached to the transmission case main body 220, and then the planetary gear unit 150 is placed in the first space 210A. Assembling work efficiency of both the units 150 and 300 can be further improved.

Next, the traveling system sub-transmission path will be described.
As described above, in the present embodiment, the transmission 100 includes the auxiliary driving wheel transmission shaft 255, the traveling system auxiliary output shaft 450, and the auxiliary driving wheel switching unit 410 that form the traveling system auxiliary transmission path. I have.
FIG. 18 is a bottom view of the transmission mechanism. In FIG. 18, the mission case 200 is schematically shown by a two-dot chain line.

As shown in FIGS. 13 and 18, the traveling system secondary output shaft 450 has the first end wall 200 a and the first intermediate in the state where the end on one side in the vehicle front-rear direction extends outward. It is supported by the wall 201a along the vehicle front-rear direction.
In the present embodiment, as shown in FIGS. 11, 14, and 16, the traveling system secondary output shaft 450 is substantially at the center of the transmission case 200 in the vehicle width direction and from the secondary driving wheel transmission shaft 255. It is arranged below.

  The auxiliary drive wheel switching unit 410 is configured to provide a two-drive state in which power transmission from the travel system main transmission path to the travel system sub output shaft 450 is blocked by the action of hydraulic pressure, and the travel system sub output shaft 450 to the A normal four-wheel drive state in which the main drive wheel output shaft 254 is rotated synchronously and a speed-up four-wheel drive state in which the traveling system sub-output shaft 450 is rotated at a higher speed than the main drive wheel output shaft 254 can be selectively obtained. It has become.

In the present embodiment, as shown in FIG. 18, the auxiliary drive wheel switching unit 410 is supported by the traveling system auxiliary output shaft 450 so as to be positioned in the first space 210A.
Specifically, as shown in FIGS. 2, 14 to 16, and 18, the auxiliary drive wheel switching unit 410 includes a housing 411 that is supported on the travel system secondary output shaft 450 so as not to be relatively rotatable, and the housing. A constant-speed transmission member 412 (L) and a speed-up transmission member that are rotatably supported by the traveling system sub-output shaft 450 in a state of being arranged in the vehicle longitudinal direction with the partition wall 411a (see FIG. 2) interposed therebetween. 412 (H) and a constant velocity side friction plate group 415 (L) for selectively engaging or releasing the power transmission from the housing 411 to the constant velocity transmission member 412 (L) by the action of hydraulic pressure (see FIG. 10). ), And a speed increasing friction plate group 415 (H) (see FIG. 10) for selectively engaging or releasing power transmission from the housing 411 to the speed increasing transmission member 412 (H) by the action of hydraulic pressure, The constant speed driven gear gear 413 (L) supported so as not to rotate relative to the constant speed transmission member 412 (L) and the speed increasing driven gear supported so as not to rotate relative to the speed increasing transmission member 412 (H). 413 (H).

  The sub-drive wheel transmission shaft 255 supports the transmission gear 273 that meshes with both the reverse drive gear 313R and the reverse drive gear 314R at a portion located in the second space 210B so as not to be relatively rotatable. In addition, in the portion located in the first space 210A, the constant speed drive gear 414 (L) and the increase gear that mesh with the constant speed driven gear 413 (L) and the speed increase driven gear 413 (H), respectively. The high-speed drive gear 414 (H) is supported so as not to be relatively rotatable.

Here, the transmission path from the traveling system main transmission path to the auxiliary drive wheel transmission shaft 255 will be described.
When the work vehicle 1 travels in the forward direction, the forward drive member 312 (F) rotates with the travel transmission shaft 253 via the F / R housing 311. The rotation of the forward drive member 312 (F) is transmitted to the main drive wheel output shaft 254 via the forward drive gear 313F and the forward driven gear 314F, and then the reverse driven gear 314R and It is transmitted to the auxiliary drive wheel transmission shaft 255 via the transmission gear 273.
At this time, the reverse drive gear 313R that meshes with the transmission gear 273 rotates together with the reverse drive member 312R, but the reverse drive member 312R moves relative to the F / R housing 311 when the vehicle moves forward. Relative rotation is possible. Therefore, the transmission gear 273 rotates without any problem in the forward direction.

  On the other hand, when the work vehicle 1 travels in the reverse direction, the reverse drive member 312R rotates together with the travel transmission shaft 253 via the F / R housing 311. The rotation of the reverse drive member 312R is transmitted to the main drive wheel output shaft 254 via the reverse drive gear 313R, the transmission gear 273, and the reverse drive gear 314R, and the reverse drive. It is transmitted to the auxiliary drive wheel transmission shaft 255 via the gear 313R and the transmission gear 273.

2, 13, 15, etc., a reference numeral 259 is a zero point detection gear for detecting whether or not the traveling speed of the working vehicle 1 is zero.
In the present embodiment, as shown in FIG. 15 and the like, the zero point detection gear 259 is accommodated above the transmission case 200 in a state of meshing with the reverse drive gear 314R.

Furthermore, as shown in FIGS. 2 and 13 to 18, the transmission 100 according to the present embodiment includes a pair of left and right hydraulic traveling systems that can apply a braking force to the traveling system main transmission path. Brake units 420L and 420R are provided.
The pair of hydraulic travel system brake units 420L and 420R are configured to be able to operatively apply braking force independently to the corresponding left and right drive axles.
In the present embodiment, the pair of traveling brake units 420L and 420R are connected to the left and right output shafts 405L and 405R of the main differential gear unit 400, as shown in FIGS. 2, 13, and 16 to 18. Each is configured such that a braking force can be applied independently.
Specifically, as shown in FIG. 10, the left and right brake units 420L and 420R have brake friction plate groups 421L and 421R, respectively. When hydraulic oil is supplied, the left and right brake units 420L and 420R are controlled by the corresponding output shaft 405. When power is applied and the supply of hydraulic oil is stopped, the corresponding braking force to the output shaft 405 is released.

Next, the PTO transmission path will be described.
The PTO clutch unit 500 is configured to selectively engage or block power transmission from the drive source 10 to the PTO shaft 260.
Specifically, the transmission 100 has a PTO clutch shaft 261 supported by the transmission case 200 along the longitudinal direction of the vehicle, as shown in FIGS. The PTO clutch shaft 261 is supported in the first space 210A.

As shown in FIG. 2, the PTO clutch unit 500 includes a PTO drive side member 501 that is operatively connected to the drive source 10 and is rotatably supported by the PTO clutch shaft 261, and the PTO clutch shaft 501. And a PTO friction plate group 505 for selectively engaging or releasing the power transmission from the PTO drive side member 501 to the clutch housing 502 according to the action of hydraulic pressure. 10).
In the present embodiment, as shown in FIG. 10, the PTO clutch unit 500 is a hydraulically operated type in which the PTO friction plate group 505 is in a power transmission state when hydraulic oil is supplied.

Furthermore, in the present embodiment, the transmission 100 includes a PTO brake unit 510 that operates contrary to the PTO clutch unit 500, as shown in FIGS.
The PTO brake unit 510 is of a spring operation type in which a braking force is applied to the clutch housing 502 by a biasing force of a spring, and the braking force is released by the hydraulic pressure of the hydraulic oil when the hydraulic oil is supplied. .

In the present embodiment, the PTO drive side member 501 meshes with the constant speed gear 271 as shown in FIGS.
That is, in the transmission 100 according to the present embodiment, both the planetary gear unit 150 and the PTO clutch unit 500 input constant speed power from the drive source 10 via the single constant speed gear 271. Thus, the number of parts can be reduced and the transmission 100 in the longitudinal direction of the vehicle can be reduced.

More specifically, in the conventional configuration, the planetary gear unit and the PTO clutch unit are displaced in the vehicle front-rear direction, and the planetary gear unit inputs a constant speed power from a drive source through one constant speed gear. In addition, the PTO clutch unit is configured to input constant speed power from a drive source via another constant speed gear.
In such a configuration, the number of parts increases and the transmission itself increases in size in the longitudinal direction of the vehicle.

  On the other hand, in the present embodiment, as described above, the planetary gear unit 150 and the PTO clutch unit 500 both input the constant speed power from the drive source 10 through the single constant speed gear 271. It is configured as follows. Therefore, the number of parts can be reduced and the vehicle can be reduced in the longitudinal direction.

Specifically, as shown in FIGS. 11 and 16, the PTO clutch shaft 261 is configured such that the HST output shaft 113 (or the speed change gear) is based on the HST input shaft 111 (or the constant speed output shaft 251). The output shaft 252) is disposed on the opposite side in the vehicle width direction.
The constant speed gear 271 is supported by the constant speed output shaft 251 so as to be positioned on the other side in the vehicle width direction in the first space 210A, as shown in FIGS.
In such a configuration, the PTO clutch unit 500 is configured such that the PTO clutch shaft 500 is positioned on one side in the vehicle front-rear direction with respect to the constant speed gear 271 with the driving side member 501 engaged with the constant speed gear 271. The planetary gear unit 150 is supported by the H.261, and the combined output shaft 154 is positioned on one side in the vehicle longitudinal direction from the constant speed gear 271 with the internal gear 152 engaged with the constant speed gear 271. Thus, the shift output shaft 252 is supported.
That is, in the present embodiment, as shown in FIGS. 12 and 13, the PTO clutch unit 500 and the planetary gear unit 150 are arranged so that at least a part thereof is located at substantially the same position in the vehicle longitudinal direction. Thus, the transmission 100 is reduced in size in the vehicle front-rear direction.

  Further, in the present embodiment, as shown in FIGS. 11 and 16, etc., the clutch housing 502 is configured to partially overlap the constant speed gear 271 in a front view along the vehicle front-rear direction. Thus, the HST input shaft 111 (the constant speed output shaft 251) and the PTO clutch shaft 261 can be arranged as close as possible while securing the capacity of the PTO clutch unit 500.

That is, if the distance between the PTO clutch shaft 261 and the constant speed output shaft 251 is increased, the PTO friction plate 505 can be enlarged to secure the capacity of the PTO clutch unit 500. With this configuration, the transmission 100 is increased in size.
On the other hand, as in the present embodiment, the clutch housing 502 is displaced from the constant speed gear 271 to one side in the vehicle front-rear direction, and a part of the clutch housing 502 is seen from the front in the constant speed gear 271. The PTO friction plate 505 can be enlarged while bringing the PTO clutch shaft 261 and the constant speed output shaft 252 as close as possible.

In this embodiment, as shown in FIGS. 11 and 16, the PTO clutch shaft 261 includes the HST input shaft 111 (the constant speed output shaft 251) and the HST output shaft 113 (the shift output shaft). 252), but above the traveling transmission shaft 253.
Therefore, the PTO clutch unit 500 supported by the PTO clutch shaft 261 is more lubricated by the stored oil in the transmission case 200 than the traveling system hydraulic switching unit 300 supported by the traveling system transmission shaft 253. It is difficult to receive.

The PTO multi-stage transmission unit 550 is accommodated in the second space 210B as shown in FIGS.
The PTO multi-stage transmission unit 550 is configured to perform multi-stage transmission between a PTO transmission shaft 262 operatively connected to the PTO clutch shaft 261 and a PTO transmission shaft 263 arranged substantially parallel to the PTO transmission shaft 262. Has been.

  Specifically, as shown in FIGS. 2, 13, 14, 17, and 18, the transmission 100 is coaxially connected to the PTO clutch shaft 261 and connected to the PTO clutch shaft 261 so as not to rotate relative to the axis. A PTO transmission shaft 262 supported along the vehicle longitudinal direction by the first intermediate wall 201a and the second intermediate wall 201b so as to be positioned in the two spaces 210B, and the PTO transmission shaft above the PTO transmission shaft 262 And a PTO transmission shaft 263 supported by the first intermediate wall 201a and the second intermediate wall 201b so as to be positioned in the second space 210B in a state substantially parallel to the H.262.

  As shown in FIGS. 13 and 18, the PTO multi-stage transmission unit 550 includes a plurality of PTO drive side transmission gears 551 that are supported on the PTO transmission shaft 262 so as not to rotate relative to each other, and the plurality of PTO drive side transmission gears 551. A plurality of PTO driven side transmission gears 552 that are rotatably supported by the PTO transmission shaft 263 in a state of being directly or indirectly engaged with each other, and the plurality of PTO driven side gears 552 are selectively connected to the PTO transmission shaft. And a PTO shift shifter 555 to be engaged with the H.263.

In the present embodiment, as shown in FIG. 2, the PTO multi-stage transmission unit 550 is configured to perform a total of five speeds including four forward rotation speeds and one reverse rotation speed.
Specifically, as shown in FIGS. 2, 13, and 18, the plurality of PTO drive side transmission gears 551 include forward rotation side first to fourth stage drive gears 551F (1) to 551F (4) and reverse rotation. The plurality of PTO driven side transmission gears 552 include forward rotation side first to fourth stage driven gears 552F (1) to 552F (4) and reverse rotation side first stage driven gear 552R. Contains.
2 and 18, the forward rotation side first to fourth stage drive gears 551F (1) to 551F (4) are respectively the forward rotation side first to fourth stage driven gears 552F. (1) to 552F (4) are directly meshed with each other, while the reverse drive gear 551R is meshed with the reverse driven gear 552R through an idle gear 553.

  2, 13 and 14, the PTO shift shifter 555 selectively selects the forward rotation side first stage driven gear 552F (1) or the forward rotation side fourth stage driven gear 552F (4). And the first / fourth stage shifter 555F (1-4) to be engaged with the PTO transmission shaft 263 and the forward rotation side second driven gear 552F (2) or the forward rotation side third driven gear 552F (3). ) Are selectively engaged with the PTO speed change shaft 263, and the second / third speed shifter 555F (2-3) and the reverse side first speed driven gear 552R are selectively engaged with the PTO speed change shaft 262. And a reverse shifter 555R to be combined.

Specifically, as shown in FIGS. 2, 13, and 14, the forward rotation side first stage driven gear 552F (1) and the forward rotation side fourth stage driven gear 552F (4) are arranged to face each other, and The forward rotation side second stage driven gear 552F (2) and the forward rotation side third stage driven gear 552F (3) are arranged to face each other.
The first / fourth stage shifter 555F (1-4) is disposed between the forward rotation side first stage driven gear 552F (1) and the forward rotation side fourth stage driven gear 552F (4). The second / third stage shifter 555F (2-3) is disposed between the forward rotation side second stage driven gear 552F (2) and the forward rotation side third stage driven gear 552F (3). Yes.

The PTO multi-stage transmission unit 550 is operated via a PTO transmission operation mechanism 560 provided in the transmission 100, as shown in FIGS.
The PTO speed change operation mechanism 560 is engaged with the first / fourth stage shifter 555F (1-4), the second / third stage shifter 555F (2-3), and the reverse shifter 555R, respectively. The first / fourth stage shift fork 561F (1-4), the second / third stage shift fork 561F (2-3) and the reverse shift fork 561R are moved along the longitudinal direction of the vehicle and in the axial direction. A forward fork shaft 562F supported by the first intermediate wall 201a and the second intermediate wall 201b so as to be possible, the first / fourth stage shift fork 561F (1-4) and the second / Fork shaft 562F for normal rotation that supports the base end side of the third-stage shift fork 561F (2-3), the first intermediate wall 201a and the first intermediate wall 201a so as to be movable in the axial direction along the vehicle longitudinal direction. 2 is a reverse fork shaft 562R supported by the intermediate wall 201b, the reverse fork shaft 562R supporting the base end side of the reverse shift fork 561R, the forward fork shaft 562F, and the reverse fork shaft 562R. A PTO operation shaft 563 supported on the transmission case 200 so as to be rotatable about the axis line and movable in the axial direction so as to be along the vehicle width direction at a higher position, and a base end portion is supported by the PTO operation shaft 563 and the PTO operation is performed. An operating arm 564 that selectively engages the forward fork shaft 562F or the reverse fork shaft 562R according to the axial movement of the shaft 563 is provided.

  The PTO operation shaft 563 moves in the axial direction when an operation member such as a PTO multi-stage shift lever provided near the driver's seat is operated in a first direction (for example, the vehicle width direction), and the operation member is moved in the first direction. Is operated and connected to the operation member so as to rotate around an axis when operated in a second direction different from (for example, the vehicle longitudinal direction).

The PTO speed change operation mechanism 560 operates as follows.
When the operating member is operated in the first direction, the PTO operating shaft 563 is moved in the axial direction, whereby the operating arm 564 is selected as either the forward fork shaft 562F or the reverse rotating fork shaft 562R. Engaging.
In this state, when the operating member is operated in the second direction, the PTO operating shaft 563 rotates around the axis, thereby causing the engaged fork shaft to move in the axial direction, The shifter engaged with the supported shift fork moves along the axis of the PTO transmission shaft 263, and a desired rotation is obtained on the PTO transmission shaft 263.

As described above, the transmission 100 supports the operation shaft 563 in the transmission case 200 so as to be movable in the axial direction and rotatable around the axial line, and moves either in the axial direction or rotated around the axial line of the operating shaft 563. The operating arm 564 is engaged with any one of the plurality of fork shafts 562F and 562R, and the operating shaft 563 is engaged by the other movement of the axial movement or rotation around the axial line. The fork shaft is configured to move in the axial direction, thereby reducing the cost by reducing the number of parts.
That is, according to the above configuration, the plurality of fork shafts 562F and 562R can be operated by the single operation shaft 563, and thereby the number of parts can be effectively reduced.

16 and 17, preferably, the forward fork shaft 562F and the reverse fork shaft 562R together with the traveling system fork shaft 362 are the PTO transmission shaft 263 and the main drive wheel in the vehicle width direction. Arranged between the output shafts 254.
By providing such a configuration, the fork shafts 362, 562F, and 562R can be installed as much as possible, and the transmission 100 can be downsized in the vertical direction.

  As shown in FIGS. 2 and 14, etc., the PTO transmission shaft 263 is connected to the third space 210C and the fourth space while being coaxially connected to the PTO transmission shaft 263 and not relatively rotatable about the axis. The PTO shaft 260 is operatively connected via a transmission shaft 264 supported by the transmission case 200 so as to extend over the space 210D and a transmission gear train 275 accommodated in the fourth space 210D. .

Next, the hydraulic circuit of the transmission 100 will be described.
First, the hydraulic circuit of the working vehicle 1 will be described.
As shown in FIG. 10, the working vehicle 1 has an auxiliary pump body that is operatively driven by the drive source 10 and acts as a hydraulic pressure source for various hydraulic power transmission units.
In the present embodiment, the working vehicle has first and second auxiliary pump bodies 51 and 52 as the auxiliary pump bodies.
That is, the working vehicle 1 includes the first and second auxiliary pump bodies 51 and 52, one end of which is fluidly connected to an oil source such as the transmission case 200 and the other end of the first and second auxiliary pumps. A suction line 601 fluidly connected to the suction sides of the main bodies 51 and 52, a first discharge line 611 whose one end is fluidly connected to the discharge side of the first auxiliary pump main body 51, and one end thereof is the second auxiliary pump. And a second discharge line 612 fluidly connected to the discharge side of the main body.

  Further, as shown in FIG. 10, the working vehicle 1 includes a power steering hydraulic circuit 60 to which pressure oil is supplied from the first auxiliary pump main body 51 via the first discharge line 611, and the power steering Pressure oil is supplied from the second auxiliary pump main body 52 via the second discharge line 612 and the transmission hydraulic circuit 65 to which surplus oil for the hydraulic circuit 60 and return oil from the power steering hydraulic circuit 60 are supplied. The horizontal posture hydraulic circuit 70 for controlling the hydraulic oil supply / discharge control for the horizontal posture hydraulic cylinder 55 provided in the work vehicle 1 and the return oil from the horizontal posture hydraulic circuit 70 are supplied, and the work vehicle 1 And an elevating hydraulic circuit 75 for controlling the supply and discharge of hydraulic fluid to the elevating hydraulic cylinder 56 for elevating the working machine attached to the machine. To have.

Here, the transmission hydraulic circuit 65 will be described.
The transmission hydraulic circuit 65 includes a hydraulic unit hydraulic circuit 65A for controlling the operation of the various hydraulic units housed in the mission case 200, and a charge line 705 for supplying hydraulic oil to the HST 110. And an HST hydraulic circuit 65B.

  As shown in FIG. 10, the hydraulic circuit for hydraulic unit 65A includes a supply line 620 fluidly connected to a hydraulic power source, a main relief valve 625 for setting the hydraulic pressure of the supply line 620, and the travel system hydraulic switching unit. Traveling system supply / discharge line 630 for supplying / discharging hydraulic oil to / from 300, and traveling for draining hydraulic oil discharged from traveling system hydraulic switching unit 300 through traveling system supply / discharge line 630 to an oil sump. System drain line 635, travel system switching valve 640 that controls supply / discharge of travel system supply / discharge line 630, PTO supply / discharge line 645 through which hydraulic fluid is supplied to and discharged from hydraulic PTO clutch unit 500, and hydraulic pressure PTO for draining hydraulic oil discharged from the PTO clutch unit 500 through the PTO supply / discharge line 645 to the oil sump Ren line 650, PTO switching valve 655 for controlling supply / discharge of the PTO supply / exhaust line 645, brake supply / discharge line 660 for supplying / discharging hydraulic oil to / from the hydraulic travel system brake unit 420, and the hydraulic travel system A brake drain line 665 for draining hydraulic oil discharged from the brake unit 420 via the brake supply / discharge line 660 to an oil sump; a brake switching valve 670 for controlling supply / discharge of the brake supply / discharge line 660; The auxiliary drive wheel supply / discharge line 675 for supplying and discharging hydraulic oil to and from the auxiliary drive wheel switching unit 410 and the hydraulic oil discharged from the auxiliary drive wheel switching unit 410 via the auxiliary drive wheel supply / discharge line 675. The auxiliary drive wheel drain line 680 for draining the oil into the oil sump and the supply / discharge control of the auxiliary drive wheel supply / discharge line 675 And a secondary drive wheel switching valve 685 which controls the.

In the present embodiment, as described above, the traveling system hydraulic switching unit 300 is the F / R switching unit 310 including the forward friction plate 315F and the reverse friction plate 315R.
Accordingly, the traveling system supply / discharge line 630 includes a forward supply / discharge line 630F and a reverse travel supply / discharge line 630R, and the traveling system switching valve 640 controls the forward switching valve 640F that controls the supply / discharge control of the forward supply / discharge line 630F. And a reverse-side switching valve 640R that controls supply / discharge of the reverse-side supply / discharge line 630R, and the traveling system drain line 635 includes a forward-side drain line 635F and a reverse-side drain line 635R.

  In the present embodiment, the transmission hydraulic circuit 65A includes a hydraulic piston switching structure 570 in order to reduce the amount of hydraulic fluid passing through the forward switching valve 635F and the reverse switching valve 635R. .

Specifically, as shown in FIG. 10, the hydraulic piston switching structure 570 biases the cylinder 571, the switching piston 572 slidably accommodated in the cylinder 571, and the switching piston 572 to the neutral position. Thus, a pair of urging members 573 disposed on both axial ends of the switching piston 572 are provided.
The switching piston 572 passes through the internal space of the cylinder 571 through the forward-side urging chamber 571F (1) in which one of the pair of urging members is accommodated and the hydraulic oil supply / discharge passage for the forward-side friction plate group 315F. A forward-side working chamber 571F (2) that forms a part of the rear-side friction plate group 315R, a reverse-side working chamber 571R (2) that forms a part of the hydraulic oil supply / discharge passage, and the pair of urging forces The other side of the member 573 is liquid-tightly divided into a reverse-side biasing chamber 571R (1).
That is, the switching piston 572 includes the forward side land portion 572F that defines the forward side biasing chamber 571F (1) and the forward side working chamber 571F (2), the forward side working chamber 571F (2), and the reverse drive. A neutral land portion 572N that defines a side working chamber 571R (2), and a reverse side land portion 572R that defines the reverse side working chamber 571R (2) and the reverse side biasing chamber 571R (2). .

The transmission hydraulic circuit 65A has a hydraulic oil line 580 having one end fluidly connected to the supply line 620 and the other end fluidly connected to the cylinder 571, and one end thereof being the forward working chamber 571F ( 2) The fluid is connected to the forward side discharge line 581F, the other end of which is fluidly connected to the oil sump, and one end is fluidly connected to the reverse side working chamber 571R (2) and the other end is fluidly connected to the oil sump. The connected backward discharge line 581R and the forward hydraulic fluid line 585F having one end fluidly connected to the forward working chamber 571F (2) and the other end fluidly connected to the forward friction plate group 315F. A reverse-side hydraulic oil line 585R having one end fluidly connected to the reverse-side working chamber 571R (2) and the other end fluidly connected to the reverse-side friction plate group 315R. That.
The other end portion of the hydraulic oil line 580 is fluidly connected to the cylinder 571 at a portion where the neutral land portion 572N is positioned when the switching piston 572 is positioned at the neutral position.

In the configuration provided with the hydraulic piston switching structure 570, the hydraulic oil in the forward supply / discharge line 630F and the reverse supply / discharge line 630R does not directly act on the corresponding friction plate group 315. Instead, it acts on the switching piston 572.
Specifically, the advance side supply / discharge line 630F has one end fluidly connected to the advance side switching valve 640F and the other end fluidly connected to the advance side biasing chamber 571F (1), and the reverse side One end of the supply / discharge line 630R is fluidly connected to the reverse switching valve 640R and the other end is fluidly connected to the reverse biasing chamber 571R (1).

The hydraulic piston switching structure 570 operates as follows.
When the forward-side switching valve 640F and the reverse-side switching valve 640R are both positioned at a shut-off position that fluidly connects the corresponding supply / discharge line 630 to the corresponding drain line 635 (state of FIG. 2), the hydraulic oil The other end portion of the line 580 is closed by the neutral land portion 572N. Accordingly, no hydraulic oil is supplied to either the forward friction plate group 315F or the reverse friction plate group 315R, and the F / R switching unit 310 is in a power shut-off state.

  On the other hand, when the forward-side switching valve 640F is positioned at a communication position where the forward-side supply / discharge line 630F is fluidly connected to the supply line 620 (at this time, the reverse-side switching valve 640R is positioned at the blocking position). The pressure oil flows from the supply line 620 into the forward side biasing chamber 571F (1) through the forward side switching valve 640F and the forward side supply / discharge line 630F. As a result, the switching piston 572 moves in a direction to reduce the reverse-side biasing chamber 571R (1), and the forward-side land portion 572F closes the forward-side discharge line 581F, and the hydraulic oil line 580 is fluidly connected to the forward friction plate 315F via the forward side working chamber 581F (2) and the forward side hydraulic oil line 585F. Therefore, the F / R switching unit 310 is in the forward state.

  Similarly, when the reverse-side switching valve 640R is positioned at a communication position where the reverse-side supply / discharge line 630R is fluidly connected to the supply line 620 (at this time, the forward-side switching valve 640F is positioned at a blocking position). ) Pressure oil flows from the supply line 620 into the reverse-side biasing chamber 571R (1) through the reverse-side switching valve 640R and the reverse-side supply / discharge line 630R. As a result, the switching piston 572 moves in a direction to reduce the forward-side biasing chamber 571F (1), and the hydraulic oil line is closed in a state where the reverse-side land portion 572R closes the reverse-side discharge line 581R. 580 is fluidly connected to the reverse friction plate 315R via the reverse operation chamber 571R (2) and the reverse operation oil line 585R. Therefore, the F / R switching unit 310 is in the reverse drive state.

  The PTO switching valve 655 selectively takes a communication position where the PTO supply / discharge line 645 is fluidly connected to the supply line 620 and a blocking position where the PTO supply / discharge line 645 is fluidly connected to the PTO drain line 650. Configured to get.

When the PTO switching valve 655 is positioned at the communication position, hydraulic oil is supplied from the supply line 620 to the PTO supply / exhaust line 645, whereby the PTO clutch unit 500 enters a power transmission state. At this time, the PTO brake unit 510 is in a brake release state.
On the other hand, when the PTO switching valve 655 is positioned at the shut-off position, the hydraulic oil is discharged from the PTO clutch unit 500 to the oil sump via the PTO supply / discharge line 645 and the PTO drain line 650. The PTO clutch unit 500 enters a power cut-off state. At this time, the PTO brake unit 510 is in a brake operating state.

In the present embodiment, the transmission 100 includes the pair of left and right hydraulic traveling system brake units 420L and 420R as the hydraulic traveling system brake unit 420 as described above.
Accordingly, the brake supply / discharge line 660 includes a left brake supply / discharge line 660L and a right brake supply / discharge line 660R, the brake drain line 665 includes a left brake drain line 665L and a right brake drain line 665R, and the brake switching The valve 670 includes a left brake switching valve 670L and a right brake switching valve 670R.

The brake switching valve 670 has a communication position where the corresponding brake supply / discharge line 660 is fluidly connected to the supply line 620, and a cutoff position where the corresponding brake supply / discharge line 660 is fluidly connected to the corresponding brake drain line 665. It is comprised so that it can take selectively.
That is, the pair of hydraulic travel system brake units 420L and 420R are in a brake operation state and a brake release state, respectively, when the corresponding brake switching valve 670 is positioned at the communication position and the cutoff position.

In the present embodiment, the auxiliary drive wheel switching unit 410 is configured so as to be able to selectively take a two-wheel drive state, a normal four-wheel drive state, or a speed-up four-wheel drive state as described above.
Accordingly, the auxiliary drive wheel supply / discharge line 675 includes a constant speed side supply / discharge line 675 (L) and an increased speed supply / discharge line 675 (H), and the auxiliary drive wheel drain line 680 is equal to the constant speed side drain line 680 (L). ) And an acceleration side drain line 680 (H), and the auxiliary drive wheel switching valve 685 includes a constant speed switching valve 685 (L) and an acceleration side switching valve 685 (H).

The auxiliary drive wheel switching valve 685 selects a communication position where the corresponding supply / discharge line 675 is fluidly connected to the supply line 620 and a cutoff position where the corresponding supply / discharge line 675 is fluidly connected to the corresponding drain line 680. It is constituted so that it can be taken.
In other words, the auxiliary drive wheel switching unit 410 has the normal 4 when the constant speed side switching valve 685 (L) is positioned at the communication position and the speed increasing side switching valve 685 (H) is positioned at the cutoff position. When the constant speed side switching valve 685 (L) is positioned at the shut-off position and the speed increasing side switching valve 685 (H) is positioned at the communication position, When both the constant speed side switching valve 685 (L) and the speed increasing side switching valve 685 (H) are positioned at the shut-off position, the two-drive state is established.

  As shown in FIG. 2, the HST hydraulic circuit 65B includes a hydraulic servo line 690 that supplies excess oil from the supply line 620 relieved by the main relief valve 625 to the hydraulic servo mechanism 125, and the hydraulic servo line. The servo relief valve 695 for setting the hydraulic pressure of 690, a pair of HST lines 700 for fluidly connecting the hydraulic pump main body 112 and the hydraulic motor main body 114 so as to form a closed circuit, and the servo relief valve 695 are used for relief. A charge line 705 for supplying excess oil from the hydraulic servo line 690 to the closed circuit, and a charge relief valve 710 for setting the hydraulic pressure of the charge line 705 are provided.

Further, in the present embodiment, the transmission hydraulic circuit 65A includes a lubricating oil line 720 for supplying lubricating oil to the traveling hydraulic switch unit 300 and the PTO clutch unit 500.
In the present embodiment, as shown in FIG. 10, the lubricating oil line 720 includes a common lubricating oil line 725 that is fluidly connected to a hydraulic pressure source, and one end that is fluidly connected to the common lubricating oil line 725 and the other. A traveling system lubricating oil line 730 whose end is fluidly connected to the friction plate group 315 of the traveling system hydraulic switching unit 300, one end is fluidly connected to the common lubricating oil line 725, and the other end is the PTO clutch. And a PTO lubricating oil line 735 fluidly connected to the friction plate group 505 of the unit 500.

A lubricating relief valve 740 that sets the hydraulic pressure of the common lubricating oil line 725 is interposed in the common lubricating oil line 725.
In the present embodiment, the common lubricating oil line 725 is configured to receive surplus oil in the charge line 705 that is relieved by the charge relief valve 710.

  Thus, by supplying the lubricating oil to the traveling system hydraulic switching unit 300 and the PTO clutch unit 500 through the common lubricating oil line 725, the lubricating oil supply structure to both the units 300 and 500 is achieved. Can be simplified.

Further, in the present embodiment, the following configuration is provided in order to efficiently supply the lubricating oil to both the units 300 and 500.
That is, as described above, the PTO clutch unit 500 is disposed above the traveling system hydraulic switching unit 300 in the mission case 200 capable of storing oil. Therefore, the PTO clutch unit 500 is less susceptible to the lubricating action of the stored oil in the transmission case 200 than the traveling system hydraulic clutch unit 300.

  In view of this point, in the present embodiment, as shown in FIG. 10, the PTO lubricating oil line 735 is fluidized to the common lubricating oil line 725 on the upstream side of the traveling system lubricating oil line 730 in the lubricating oil flow direction. In addition, the throttle 740 is provided in a region located between the connection point with the PTO lubricant line 735 and the connection point with the traveling system lubricant line 730 in the common lubricant line 725.

As described above, one of the plurality of transmission units (in the present embodiment, the PTO clutch unit 500 and the traveling system hydraulic switching unit 300) installed in the transmission case 200 at the upper side (the main unit) In the embodiment, one lubricating oil line (in the present embodiment, the PTO lubricating oil line 735) corresponding to the PTO clutch unit 500) is replaced with the other lubricating oil line (in the present embodiment, A fluid connection to the common lubricating oil line 725 upstream of the traveling lubricating oil line 730) in the lubricating oil flow direction, and a connection point of the common lubricating oil line 725 to the one lubricating oil line; By providing the restrictor 740 in a region located between the connection points with the other lubricating oil line, It can be supplied preferentially lubricant to less susceptible the one transmission unit lubricant action by the stored fluid in the transmission case 200.
Therefore, both the units can be efficiently lubricated while obtaining the effect of simplifying the lubricating oil supply structure by using the common lubricating oil line 725.

Here, each said switching valve is demonstrated.
Each of the switching valves is an electromagnetic valve, and is operated to be turned ON / OFF according to the operation of an operation member provided near the driver's seat.

  19 to 21 show a left perspective view, a right perspective view, and a front view of a front portion of the transmission 100 that is located on the front side of the first cover member 230. FIG. 19 and FIG. 20 are views of the vehicle traveling direction as viewed from the left side and the front side, respectively, and those facing the vehicle traveling direction as viewed from the right side and from the front side. 19 and 20 show the following first and second lid members 245a and 245b in an exploded state, and FIG. 21 shows a state in which the following first and second lid members 245a and 245b are deleted. .

  As shown in FIG. 5 to FIG. 6 and FIG. 19 to FIG. 21, each switching valve is detachably attached to the first end wall 200a of the mission case 200 directly or indirectly from one side in the vehicle longitudinal direction. ing.

Specifically, as described above, the HST 110 is connected to the first end wall 200a, and the traveling system auxiliary output shaft 450 (see FIG. 3 and the like) is supported at a position below the HST 110. .
Each of the switching valves is mounted in a region of the first end wall 200a that is below the HST 110 and that is displaced in the vehicle width direction with respect to the traveling system sub output shaft 450.
In the present embodiment, the switching valves are distributed and arranged on both sides of the traveling system auxiliary output shaft 450 in the vehicle width direction.
As described above, each switching valve can be mounted on the first end wall 200a from one side in the vehicle front-rear direction, thereby preventing the switching valve from contacting an external object while preventing the vehicle width from being increased. It can be effectively prevented.

That is, in the conventional configuration in which the switching valve is mounted on the side wall of the transmission case, the switching valve protrudes outward in the vehicle width direction from the transmission case, and the PTO valve is in contact with an external object. There is a risk of damage.
In the configuration in which the switching valve is mounted on the side wall of the transmission case, the switching valve can be configured to be covered by the pair of main frames. The main frame separation interval must be increased, resulting in an increase in the vehicle width. Furthermore, when the switching valve is attached to and detached from the transmission case, there is a problem that the pair of main frames become an obstacle.

On the other hand, in the present embodiment, the switching valve can be detached from the first end wall 200a of the mission case 200 directly or indirectly from one side in the vehicle front-rear direction.
That is, in the present embodiment, the drive source unit 10A including the drive source 10 disposed on one side in the vehicle front-rear direction, the transmission case 200 spaced from the drive source unit 10A in the vehicle width direction, The switching valve is mounted on the first end wall 200a of the mission case 200 using a space defined by the drive source unit 10A and the pair of main frames 6 connecting the mission case 200. .
Therefore, it is possible to effectively prevent the switching valve from coming into contact with an external object without increasing the separation width of the pair of main frames 6. Further, the switching valve can be easily attached and detached using the space.

  In the present embodiment, as shown in FIGS. 19 to 21, the plurality of switching valves are recesses 240 that are provided directly or indirectly in the mission case 200 so as to open outward, and are attached and detached. It is accommodated in a recess 240 that forms a liquid-tight closed space in cooperation with a lid member 245 that can be mounted.

In this way, by accommodating the plurality of switching valves in the closed space, it is not necessary to provide a drain line for each of the plurality of switching valves, thereby simplifying the oil passage structure. .
That is, as described above, the switching valve is configured to selectively fluidly connect a corresponding supply / discharge line to the supply line 620 or the corresponding drain line. Accordingly, it is usually necessary to provide a number of drain lines corresponding to the number of the switching valves.
That is, when seven switching valves are provided as in the present embodiment, usually seven drain lines are required.

On the other hand, in the present embodiment, the plurality of switching valves are accommodated in a closed space formed by the recess 240 and the lid member 245.
Specifically, as shown in FIGS. 19 to 21, the transmission 100 is a first recess 240 a that is provided directly or indirectly in the mission case 200 so as to open outward, and is detachable. A first recess 240a that forms a liquid-tight first closed space in cooperation with the first lid member 245a to be mounted, and a second that is provided directly or indirectly in the mission case 200 so as to open outward. The concave portion 240b includes a second concave portion 240b that cooperates with a second lid member 245b that is detachably attached to form a liquid-tight second closed space.
Four of the seven switching valves are accommodated in the first closed space, and the other three are accommodated in the second closed space.

Thus, by accommodating a plurality of switching valves in one closed space, it is possible to share a drain line corresponding to the plurality of switching valves, thereby simplifying the drain structure. .
Specifically, the plurality of switching valves are configured to fluidly connect a corresponding supply / exhaust line to the closed space when positioned at the shut-off position, and at least one drain line is provided in the closed space. 246 is fluidly connected.
In the present embodiment, as shown in FIG. 21, two first drain lines 246a are fluidly connected to the first closed space, and two second drain lines are connected to the second closed space. 246b is fluidly connected.

By the way, in this embodiment, as described above, the transmission 1 includes the traveling system hydraulic switching unit 300, the PTO clutch unit 500, the hydraulic traveling system brake unit 420, and the auxiliary drive wheel switching unit 410. I have.
However, these transmission units are appropriately selected according to necessity or specification.
That is, when the transmission 100 is applied to a two-wheel drive work vehicle that does not need to drive the auxiliary drive wheels 35, the auxiliary drive wheel switching unit 410 is deleted and replaced with the hydraulic travel system brake unit 420. When applied to a working vehicle equipped with a mechanical travel system brake unit, hydraulic equipment related to the hydraulic travel system brake unit 420 such as the brake switching valve 670 is deleted.

It is desired that the transmission 100 can easily cope with such various specifications.
In this regard, in the present embodiment, a switching valve corresponding to a transmission unit (hereinafter referred to as an essential transmission unit) that is likely to be provided in many specifications among the transmission units is provided with one recess and one lid member. A switching valve corresponding to a transmission unit (hereinafter referred to as an optional transmission unit) that is accommodated in one closed space formed by the above-mentioned and is likely to be deleted depending on specifications is formed by another recess and another lid member. In other closed spaces, the switching valve can be easily attached and detached when the specification is changed.

  Specifically, as shown in FIGS. 3 and 19 to 21, the transmission 1 is provided below the first HST 110 and on both sides of the traveling system auxiliary output shaft 450 in the vehicle width direction. A recess 240a and the second recess 240b are provided. The first and second recesses 240a and 240b cooperate with the first and second lid members 245a and 245b to form liquid-tight first and second closed spaces, respectively.

  In the first closed space, the forward-side switching valve 640F, the reverse-side switching valve 640R, and the PTO valve corresponding to the traveling system hydraulic switching unit 300 and the PTO clutch unit 500, which are the essential transmission units, are provided. 655 is accommodated in the second closed space, the constant speed side switching valve 685 (L) corresponding to the auxiliary drive wheel switching unit 410 and the traveling system hydraulic brake unit 420 which are the arbitrary transmission units, The acceleration side switching valve 685 (H), the left brake switching valve 670 (L), and the right brake switching valve 670 (R) are accommodated.

  In such a configuration, it is easy to change the specifications between the aspect including the auxiliary drive wheel switching unit 410 and / or the pair of traveling system hydraulic brake units 420 and the aspect not including both or one of them. be able to.

Here, a detailed configuration of the hydraulic line such as the supply line 620 will be described.
22 to 24 show a front exploded perspective view, a right rear perspective view, and a left rear perspective view of the front portion of the transmission 100, respectively.
As shown in FIGS. 22 to 24, the transmission 100 has an oil passage block 750 that is detachably connected to the first end wall 200a.
25 and 26 show an exploded front perspective view and an exploded rear perspective view of the oil passage block 750, respectively.

As shown in FIGS. 22 to 26, the oil passage block 750 allows the traveling system secondary output shaft 450 that outputs rotational power toward the auxiliary drive wheels 35 to protrude to one side in the vehicle longitudinal direction. It has a different shape.
In the present embodiment, the oil passage block 750 is provided with an opening 750a through which the output end of the traveling system sub output shaft 450 is inserted.

The oil passage block 750 is provided with first and second valve installation areas in which the plurality of switching valves are mounted.
Specifically, as shown in FIG. 25 and the like, in the present embodiment, the first and second recesses 240a and 240b are formed in the oil passage block 750, and the first and second recesses 240a and 240b are formed. Respectively form the first and second valve installation regions.

  Further, the oil passage block 750 is a supply oil passage that forms a part of the supply line 620 and is configured to guide the pressure oil supplied from a hydraulic source to each of the switching valves. A supply oil passage is provided.

  When viewed along the axial direction of the traveling system sub-output shaft 450, the supply oil passage has one end and the other end overlapped with the first and second valve installation regions, respectively, and the one end The first and second valves are installed in a substantially semicircular shape extending around the axis of the secondary output shaft 450 in a state where the portion and the other end portion surround the upper side of the secondary output shaft 450. The structure for supplying pressure oil to the plurality of switching valves mounted in the region is simplified.

  Specifically, as shown in FIGS. 22 to 26, the oil passage block 750 has an outer end surface facing the one side in the vehicle width direction, which is a direction facing the drive source 10, and a side opposite to the outer end surface. It has a block main body 751 having an inner end face that faces and a plate 752 that comes into contact with the inner end face of the block main body 751.

27 and 28 are a front view and a rear view of the block main body 751. FIG.
As shown in FIGS. 27 and 28, the block main body 751 is positioned on both sides in the vehicle width direction with the opening 750a through which the traveling system sub-output shaft 450 is inserted and the outer end surface across the opening 750a. The first and second recesses 240a and 240b provided in the portion and a plurality of oil grooves provided in the inner end surface are provided.

The plurality of oil grooves cooperate with the plate 752 to form various oil passages including the supply oil passage.
As shown in FIG. 28, when the plurality of oil grooves are viewed along the axial direction of the traveling system auxiliary output shaft 450, the one end side 760a and the other end side portion 760b are respectively connected to the first recess 240a and the first recess 240a. 2 Supply oil that overlaps with the recess 240b and has a substantially arcuate shape around the axis of the travel system sub-output shaft 450 so that the space between the one end side 760a and the other end side surrounds the opening 750a. A groove 760 is included.

The one end side 760a of the supply oil groove 760 is, as shown in FIGS. 27 and 28, a running supply opened in the first recess 240a so as to supply pressure oil to the running system switching valve 640. An end portion 761 and a PTO supply end portion 762 opened in the first recess 240a so as to supply pressure oil to the PTO switching valve 655 are provided.
In the present embodiment, as described above, the travel system switching valve 640 includes the forward switching valve 640F and the reverse switching valve 640R. Accordingly, the travel supply end 761 includes a forward supply end 761F and a reverse supply end 761R.

The other end 760b of the supply oil groove 760 is, as shown in FIGS. 27 and 28, a brake supply that is opened in the second recess 240b so as to supply pressure oil to the brake switching valve 670. An end portion 763 and a sub driving wheel supply end portion 764 opened in the second recess 240b so as to supply pressure oil to the sub driving wheel switching valve 685 are provided.
In the present embodiment, the brake switching valve 670 includes a left brake switching valve 670L and a right brake switching valve 670R, and the auxiliary driving wheel switching valve 685 is a constant speed switching valve 685 (L) and an acceleration switching valve. 685 (H) is included. Accordingly, the brake supply end portion 763 includes a left brake supply end portion 763L and a right brake supply end portion 763R, and the auxiliary drive wheel supply end portion 764 includes a constant speed supply end portion 764 (L) and an increase. A speed supply end 764 (H) is included.

According to such a configuration, if pressure oil from a hydraulic pressure source is supplied to any part of the supply oil path formed by the supply oil groove 760 and the plate 752, pressure is applied to all of the plurality of switching valves. Can guide the oil.
In the present embodiment, a pressure oil receiving port 910 (see FIG. 23) is formed on the right side surface of the transmission case 200, and the supply oil groove is provided via an oil passage provided in the first end wall 200a. Pressure oil is supplied to a position 760IN (see FIG. 28) in the vicinity of the other end 760b of the 760.
Reference numeral 626 in FIG. 23 is a mounting hole in which the main relief valve 625 is mounted.

  Further, as shown in FIGS. 27 and 28, the plurality of oil grooves form a traveling system supply / exhaust oil passage that forms part of the traveling system supply / discharge line 630 in cooperation with the plate 752. A supply / discharge oil groove 765, a PTO supply / discharge oil groove 770 that forms a PTO supply / discharge oil path that forms part of the PTO supply / discharge line 645 in cooperation with the plate 752, and the auxiliary drive wheel supply / discharge line 675. A sub-drive wheel oil supply / discharge oil groove 775 formed in cooperation with the plate 752 and a brake oil supply / discharge oil passage formed as a part of the brake supply / discharge line 660. And a brake oil supply / drain groove 780 formed in cooperation with the plate 752.

  The travel system supply / discharge oil groove 765 includes a forward-side supply / discharge oil groove 765F and a reverse-side supply / discharge oil groove 765R. The brake supply / discharge oil groove 780 includes a left brake supply / discharge oil groove 780L and a right brake supply / discharge oil groove 780R.

  The forward-side supply / discharge oil groove 765F and the reverse-side supply / discharge oil groove 765R are opened in the first recess 240a so that one end thereof is fluidly connected to the corresponding switching valve 640, and the other end is provided. It is fluidly connected to an oil passage or pipe provided in the mission case 200 through an opening formed in the plate 752 and the first end wall 200a.

The PTO supply / discharge oil groove 770 is opened in the first recess 240a so that one end thereof is fluidly connected to the corresponding switching valve 655, and the other end is connected to the travel system from the supply / discharge oil groove 760. It extends to the opposite side of the auxiliary output shaft 450 in the vehicle width direction at a radially outward position with respect to the axis of the auxiliary output shaft 450.
That is, the PTO clutch unit 500 and the PTO switching valve 655 are arranged on one side and the other side in the vehicle width direction with respect to the traveling system sub output shaft 450 as a reference.
Therefore, by extending the other end portion of the PTO supply / drain oil groove 770 to the opposite side of the one end portion with the traveling system sub output shaft 450 interposed therebetween, the other end portion and the PTO clutch unit 500 are connected to each other. The oil passage structure in between can be simplified.

As shown in FIG. 10, a PTO modulator 646 that prevents the hydraulic pressure of the hydraulic oil with respect to the PTO friction plate group 505 from increasing suddenly is inserted in the PTO supply / discharge line 645.
As shown in FIG. 28, the PTO oil supply / drain groove 770 includes a plurality of oil grooves 770a to 770c that are independent from each other in order to insert the PTO modulator 646 into the PTO supply / discharge line 645 efficiently. is doing.

  The constant speed side oil supply / discharge groove 775 (L) and the speed increase side oil supply / discharge groove 775 (H) are opened in the second recess 240 b so that one end thereof is fluidly connected to the corresponding switching valve 685. In addition, the other end is fluidly connected to an oil passage or a pipe provided in the transmission case 200 through an opening formed in the plate 752 and the first end wall 200a.

  The left brake supply / discharge oil groove 780L and the right brake supply / discharge oil groove 780R are opened in the second recess 240b so that one end thereof is fluidly connected to the corresponding switching valve 670, and the other end is formed. It is fluidly connected to corresponding brake discharge ports 781L and 781R (see FIG. 23) provided on the right side surface of the transmission case 200 through oil passages formed in the plate 752 and the first end wall 200a. The pressure oil discharged from the brake discharge port 781 is supplied to the corresponding brake unit 420 via an appropriate external pipe.

  Further, as shown in FIG. 28, the plurality of oil grooves include a servo oil groove 790 that forms an oil passage that forms part of the hydraulic servo line 690 in cooperation with the plate 752, and the charge line 705. A charge oil groove 795 that forms a part of the oil passage in cooperation with the plate 752 is included.

FIG. 29 shows a vertical rear view of the port block 117.
The servo oil groove 790 receives the relief oil from the main relief valve 625 attached to the transmission case 200 at one end side 790a, and the servo oil passage formed in the port block 117 from the other end side 790b. 691 (see FIG. 29) is configured to supply pressure oil.

  The charge oil groove 795 receives relief oil from the servo relief valve 695 (see FIGS. 2 and 29) mounted on the port block 117 on one end side 795a, and the other end side 795b is on the HST input shaft. 111 and the HST output shaft 113 are extended to the opposite side in the vehicle width direction, thereby forming the charge line 705 while preventing the port block 117 from being enlarged.

  That is, as in the present embodiment, the HST input shaft 111 and the HST output shaft 113 are arranged in parallel in the vehicle width direction, and the hydraulic servo mechanism 125 includes the HST input shaft 111 and the HST output shaft 113. When arranged on one side in the vehicle width direction, the charge line 705 is connected to the HST input shaft 111 and the HST output to prevent the charge line 705 and the hydraulic servo line 690 from interfering with each other. It is preferable that the hydraulic servo mechanism 125 is configured to be fluidly connected to the pair of HST oil passages 701 on the side opposite to the hydraulic servo mechanism 125 with respect to the shaft 113.

  In view of this point, in the present embodiment, as shown in FIG. 29, the port block 117 includes the hydraulic servo line on one side in the vehicle width direction on the basis of the HST input shaft 111 and the HST output shaft 113. 690 has a hydraulic servo oil passage 691 that forms a part of 690 and a charge oil passage 706 that forms a part of the charge line 705 on the other side in the vehicle width direction.

  Accordingly, the relief oil from the servo relief valve 695 inserted in the hydraulic servo oil passage 691 disposed on one side in the vehicle width direction with respect to the HST input shaft 111 and the HST output shaft 113 is used as the oil. By guiding the other side in the vehicle width direction through the charge oil groove 795 in the road block 750, the excess oil of the hydraulic servo line 690 is transferred to the charge oil path 706 while preventing the port block 117 from becoming large. Can be supplied.

The oil passage block 750 is further formed with a common lubricating oil passage that forms a part of the common lubricating oil line 725.
The common lubricating oil path includes a lubricating oil receiving port that is fluidly connected to a hydraulic pressure source, a PTO lubricating oil discharge port that discharges lubricating oil toward the PTO lubricating oil line 735, and the traveling system lubricating oil line 730. And a running system lubricating oil discharge port for discharging the lubricating oil.
The PTO lubricating oil discharge port is located upstream of the traveling system lubricating oil discharge port in the lubricating oil flow direction.

In the present embodiment, as described above, the oil passage block 750 includes the block body 751 and the plate 752. The common lubricating oil passage is formed by an oil groove formed in the block main body 751 and the plate 752.
That is, as shown in FIG. 28, the plurality of oil grooves further include a common lubricating oil groove 800 that forms the common lubricating oil passage in cooperation with the plate 752.

The common lubricating oil groove 800 extends from one side to the other side in the vehicle width direction with reference to the HST input shaft 111.
Specifically, the common lubricating oil groove 800 is a lubricating oil receiving area 800IN corresponding to the lubricating oil receiving port, and is a lubricating oil receiving area provided on one side in the vehicle width direction with respect to the HST input shaft 111. 800IN, a PTO lubricating oil discharge region 801OUT corresponding to the PTO lubricating oil discharge port, a PTO lubricating oil discharge region 801OUT provided on one side in the vehicle width direction from the HST input shaft 111, and the traveling system lubricating oil A travel system lubricant oil discharge area 802OUT corresponding to the discharge port, and a travel system lubricant oil discharge area 802OUT provided on the other side in the vehicle width direction with respect to the HST input shaft 111 is provided.

  Further, a narrow region 803 is formed in the common lubricant groove 800 between the PTO lubricant discharge region 801OUT and the traveling system lubricant discharge region 802OUT, and the narrow region 803 is the throttle 740. Is forming.

As described above, the common lubricating oil passage extending from one side to the other side in the vehicle width direction with respect to the HST input shaft 111 is provided in the oil passage block 750 connected to the first end wall 200a of the transmission case 200. By forming the PTO clutch unit 500 and the traveling system hydraulic switching unit 300 distributed in the vehicle width direction on one side and the other side in the mission case 200 with respect to the HST input shaft 111, the efficiency is improved. Lubricating oil can be supplied.
Further, the narrow region 803 is formed in the common lubricant groove 800 that forms the common lubricant passage, and the restrictor 740 is formed by the narrow region 803. Therefore, the restrictor 740 is easily formed. can do.

  Further, as shown in FIG. 28, the PTO lubricating oil discharge region 801OUT corresponding to the PTO lubricating oil discharge port is configured to be located above the traveling system lubricating oil discharge region 802OUT corresponding to the traveling system lubricating port. Thus, the lubricating oil can be reliably supplied to the traveling system lubricating oil port located downstream in the lubricating oil flow direction.

  The PTO lubricating oil discharge port is fluidly connected to the friction plate group 505 of the PTO clutch unit 500 via the PTO lubricating oil line 735 including an oil passage formed in the first end wall 200a. The traveling system lubricating oil discharge port is fluidly connected to the friction plate group 315 of the traveling system hydraulic switching unit 300 via the traveling system lubricating oil line 730 including an oil passage formed in the first end wall 200a. ing.

In the present embodiment, as described above, surplus oil from the charge line 705 is supplied to the common lubricating oil line 725.
Specifically, the common lubricating oil line 725 has one end fluidly connected to the secondary side of the charge relief valve 710 and the other end in the vehicle width direction of the transmission case 200 in addition to the common lubricating oil passage. Common lubricating oil first oil passage 805 (see FIG. 24) opened in the side wall, one end portion opened in the side wall in the vehicle width direction of the transmission case 200, and the other end portion in the common lubricating oil passage. The common lubricating oil second oil passage 806 (see FIG. 23) fluidly connected to the common lubricating oil receiving port of the first oil passage 805 and one end of the second oil passage 806 are fluidly connected. External piping (not shown).

FIG. 1 is a side view of a working vehicle to which a transmission according to an embodiment of the present invention is applied. FIG. 2 is a schematic diagram of transmission of the working vehicle shown in FIG. FIG. 3 is a front view of the transmission according to the embodiment of the present invention. FIG. 4 is a plan view of the transmission shown in FIG. FIG. 5 is a perspective view of the transmission shown in FIGS. 3 and 4. FIG. 6 is an exploded perspective view of the transmission shown in FIGS. FIG. 7 is a longitudinal side view of the transmission case in the transmission shown in FIGS. 8 is an exploded vertical perspective view of the mission case shown in FIG. FIG. 9 is a rear perspective view of the mission case shown in FIGS. 7 and 8. FIG. 10 is a hydraulic circuit diagram of the working vehicle. FIG. 11 is a front view of the transmission, showing a state where a first cover member is removed from the transmission case. FIG. 12 is a plan view of the transmission in the state shown in FIG. FIG. 13 is a plan view of a transmission mechanism including a transmission unit and a transmission shaft housed in the transmission case. FIG. 14 is a perspective view of the transmission mechanism shown in FIG. 13 as viewed from one side in the vehicle width direction and one side in the vehicle front-rear direction. FIG. 15 is a perspective view of the transmission mechanism as viewed from the other side in the vehicle width direction and one side in the vehicle front-rear direction. FIG. 16 is a front view of the transmission mechanism. FIG. 17 is a longitudinal front view of the transmission mechanism as viewed from the other side in the vehicle width direction from the end surface on the other side in the vehicle width direction of the first intermediate wall in the transmission case. FIG. 18 is a bottom view of the transmission mechanism. FIG. 19 is a front perspective view of only the front portion of the transmission as viewed from the other side in the vehicle width direction. FIG. 20 is a front perspective view of the front portion of the transmission shown in FIG. 19 viewed from one side in the vehicle width direction. FIG. 21 is a front view of the front portion of the transmission shown in FIGS. 19 and 20. FIG. 22 is an exploded perspective view of the front portion of the transmission shown in FIGS. 19 to 21 as viewed from the other side in the vehicle width direction and from the front. FIG. 23 is an exploded perspective view of the front portion of the transmission shown in FIGS. 19 to 22 as viewed from one side in the vehicle width direction and from the rear. FIG. 24 is an exploded perspective view of the front portion of the transmission shown in FIGS. 19 to 23 as viewed from the other side in the vehicle width direction and from the rear. FIG. 25 is an exploded perspective view of the oil passage block connected to the first end wall of the transmission case as viewed from the other side in the vehicle width direction and from the front. FIG. 26 is an exploded perspective view of the oil passage block as viewed from the other side in the vehicle width direction and from the rear. FIG. 27 is a front view of a block body in the oil passage block. 28 is a rear view of the block main body shown in FIG. FIG. 29 is a longitudinal rear view of the port block in the HST provided in the transmission.

Explanation of symbols

1 Working vehicle 6 Main frame 10 Drive source 30 Rear wheel (main drive wheel)
35 Front wheel (sub drive wheel)
100 Transmission 110 HST
111 HST input shaft 200 Mission case 200a First end wall 240a First recess 240b Second recess 245a First lid member 245b Second lid member 246a First drain line 246b Second drain line 260 PTO shaft 300 Traveling system hydraulic switching unit 410 Hydraulic Sub Drive Wheel Switching Unit 450 Traveling System Sub-output Shaft 500 Hydraulic PTO Clutch Unit 640F Forward Side Switching Valve (Travel System Switching Valve)
640R Reverse side switching valve (travel system switching valve)
655 PTO switching valve 685 (L) constant speed switching valve (sub drive wheel switching valve)
685 (H) Speed-up side switching valve (sub-drive wheel switching valve)
750 Oil passage block 751 Block body 752 Plate 760 Supply oil groove 765 Travel system supply / discharge oil groove 770 PTO supply / discharge oil groove 775 Sub drive wheel supply / discharge oil groove

Claims (5)

Vehicles of the pair of main frames in a state where they are separated from the drive source supported directly or indirectly on one side in the vehicle longitudinal direction of the pair of left and right main frames arranged along the vehicle longitudinal direction. A transmission case connected to the other side in the front-rear direction, an HST supported on the first end wall on one side of the vehicle front-rear direction in the transmission case, a hydraulic transmission unit housed in the transmission case, and the hydraulic transmission unit A transmission for a working vehicle comprising a switching valve for switching the transmission state of
The transmission is characterized in that the switching valve is detachable directly or indirectly from one side in the vehicle front-rear direction to the first end wall of the mission case. A traveling system auxiliary output shaft supported by the transmission case so as to output toward the auxiliary driving wheel on one side in the vehicle longitudinal direction,
2. The transmission according to claim 1, wherein the switching valve is mounted in a region below the HST and displaced in a vehicle width direction with respect to the traveling system auxiliary output shaft. The hydraulic transmission unit is disposed on the rear side in the vehicle longitudinal direction from the drive source, and a hydraulic PTO clutch unit that selectively engages or shuts off a PTO transmission path that transmits rotational power from the drive source to the PTO shaft. A traveling system hydraulic switching unit that switches the transmission state of the traveling system main transmission path leading to the main driving wheel, and a hydraulic auxiliary driving wheel switching unit that switches the transmission state to the auxiliary driving wheel,
The PTO clutch unit is disposed on one side in the vehicle width direction with respect to the traveling system auxiliary output shaft, and the traveling system hydraulic switching unit is disposed on the other side in the vehicle width direction with reference to the traveling system auxiliary output shaft. And
The switching valve includes a PTO switching valve that switches a transmission state of the PTO clutch unit, a traveling system switching valve that switches a transmission state of the traveling hydraulic switching unit, and a sub-drive that switches a transmission state of the auxiliary driving wheel switching unit. Including a wheel switching valve,
The transmission according to claim 2, wherein the PTO switching valve, the traveling system switching valve, and the auxiliary driving wheel switching valve are arranged in a vehicle width direction with the auxiliary output shaft interposed therebetween. An oil passage block detachably attached to the first end wall of the mission case;
The oil passage block includes first and second recesses that are provided on both sides of the auxiliary output shaft in the vehicle width direction so as to open to one side in the vehicle front-rear direction, and are detachably mounted. First and second recesses that cooperate with the members to form liquid-tight first and second closed spaces, a supply oil passage that supplies hydraulic oil from a hydraulic source to the first and second closed spaces, A supply / discharge oil passage for traveling whose one end is opened in the first closed space, a supply / discharge oil passage for PTO whose one end is opened in the first closed space, and one end of the second closed space. A sub-drive wheel oil supply / discharge oil passage opened in the inside, a first drain oil passage whose one end is opened in the first closed space, and a second drain whose one end is opened in the second closed space. An oil passage,
The travel system switching valve is accommodated in the first closed space so as to selectively fluidly connect the travel supply / discharge oil path to the supply oil path or the first closed space,
The PTO switching valve is housed in the first closed space so as to selectively fluidly connect the PTO supply / discharge oil passage to the supply oil passage or the first closed space,
The auxiliary drive wheel switching valve is accommodated in the second closed space so as to selectively fluidly connect the auxiliary drive wheel supply / discharge oil passage to the supply oil passage or the second closed space. The transmission according to claim 3. The oil passage block has a block main body in which the first and second recesses are formed, and a plate that comes into contact with an end surface of the block main body in the vehicle front-rear direction,
The end surface of the block body on the other side in the vehicle front-rear direction cooperates with the plate to supply the supply oil passage, the travel supply / discharge oil passage, the PTO supply / discharge oil passage, and the auxiliary drive wheel supply / discharge oil. The transmission according to claim 4, wherein a plurality of oil grooves that respectively form paths are formed.