JPH1182643A - Transmission of working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorter the longitudinal length of a transmission which has been longer since the advance and backing converting mechanism at the transmission upper side, and the multistage change mechanism at the transmission lower side are portioned out at the front side and the rear side conventionalily, in the transmission for working vehicle composed between an input shaft interlocked to an engine, and an output shaft provided parallel to the input shaft, and inter-locked to the rear wheels. SOLUTION: A second running change shaft 9 is provided at the same axial line with a running input shaft 7, and a front side running output shaft 10 integral with a rear side running output shaft 11 and a first running change shaft 8 are arranged in parallel. A first clutch device of a synchromesh mechanism 41 to convert and select the advance low speed and the backing is provided at the first running change shaft 8, a second clutch device for advance high speed is provided between the running input shaft 7 and the second running change shaft 9, and a third clutch device for muitistage change is provided at the third running change shaft 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving system comprising a traveling input shaft interlocked with an engine of a work vehicle such as a tractor, and a traveling output shaft disposed parallel to the traveling input shaft and interlocked with a rear wheel. It relates to the structure of the transmission configured.

[0002]

2. Description of the Related Art Conventionally, a transmission configured between a traveling input shaft interlocked with an engine of a work vehicle such as a tractor and a traveling output shaft disposed parallel to the traveling input shaft and interlocked with rear wheels. In the forward high speed, forward low speed,
The first transmission on the upper drive side that can be set in each state of reverse and the reverse, the second transmission on the lower drive side that can set the speed in multiple stages for each setting of the first transmission, It is known from Japanese Patent Publication No. 5-26686.

[0003]

In the prior art transmission, the first transmission on the upper drive side is disposed at the front of the vehicle body, and the second transmission is disposed at the rear of the vehicle body. Becomes longer. If the first transmission and the second transmission can be provided in parallel, the front-rear length can be shortened and the vehicle can be made more compact. Further, the front-wheel power take-out portion that branches off from the lower side of the transmission can be disposed further forward, and can be closer to the drive portion of the front wheel axle, thereby improving the responsiveness of front-wheel drive. In Japanese Patent Publication No. Hei 5-26686, the shift pattern of each shift lever for operating each transmission is such that the operation lever of the first transmission is a straight type and that of the second transmission is an H type. However, the second transmission, which is a multi-stage transmission mechanism, is often used during traveling, and is desired to be easier to operate.

[0004]

The present invention uses the following means in order to solve the above-mentioned problems concerning the transmission of a work vehicle. First, the invention according to claim 1 is configured such that a driving input shaft interlocked with an engine of a work vehicle and a driving output shaft disposed in parallel with the driving input shaft and interlocked with a rear wheel. Transmission, wherein a first traveling speed change shaft constantly driven by the traveling input shaft is provided in parallel with the traveling output shaft,
A second traveling transmission shaft parallel to the first traveling transmission shaft is provided on the same axis as the traveling input shaft so as to be opposed to each other, and a forward / reverse switching mechanism is provided between the first traveling transmission shaft and the second traveling transmission shaft. And a multi-stage transmission mechanism interlocked with a forward / reverse switching mechanism between the second traveling transmission shaft and the traveling output shaft.

[0005] Next, a second aspect of the present invention provides a driving input shaft which is interlocked with the engine of the work vehicle, and a driving output shaft which is disposed parallel to the driving input shaft and is interlocked with the rear wheels. A transmission configured between
A first traveling speed change shaft always driven by the traveling input shaft is provided in parallel with the traveling output shaft, and a second traveling speed changing shaft parallel to the first traveling speed change shaft is provided on the same axis as the traveling input shaft so as to face the traveling input shaft. A forward reduction gear train and a reverse rotation gear train between the first traveling transmission shaft and the second traveling transmission shaft, and a plurality of reduction gear trains between the second traveling transmission shaft and the traveling output shaft. A first clutch device, which can select one of a forward rotation reduction gear train and a reverse rotation gear train to transmit from the first traveling speed change shaft to the second traveling speed change shaft, a forward rotation reduction gear train and a reverse rotation gear A second clutch device capable of directly connecting the traveling input shaft and the second traveling speed change shaft when any of the trains is in the non-transmission state, and traveling from the second traveling speed change shaft by selecting any of a plurality of reduction gear trains; A third clutch device capable of transmitting power to the output shaft is provided.

According to a third aspect of the present invention, there is provided a vehicle, comprising: a travel input shaft interlocked with an engine of a work vehicle; and a travel output shaft disposed parallel to the travel input shaft and interlocked with wheels. A transmission configured to
A first traveling speed change shaft always driven by the traveling input shaft is provided in parallel with a traveling output shaft, and a second traveling speed change shaft parallel to the first traveling speed change shaft is opposed to the traveling input shaft on the same axis. A first drive gear for driving the second traveling speed change shaft in the forward rotation direction on the first traveling speed change shaft, and a second drive gear constantly meshed with an idle gear that is idlely fitted on the traveling output shaft. A first clutch capable of idlely fitting a second drive gear for driving the traveling speed change shaft in the reverse direction, and selecting one of the first and second drive gears to be coupled to the first traveling speed change shaft. A second clutch device capable of directly connecting both shafts when both gear trains are in a non-transmission state between the traveling input shaft and the second traveling speed change shaft; A plurality of drive gears are fixed on the shaft, and each drive gear on the second traveling speed change shaft is always provided on the travel output shaft. The driven gear for engagement with fitted idle outside, is intended to provide a third clutch device capable of binding to the traveling output shaft selects one of the driven gears. Further, in the invention of claim 3, means taken by the invention according to claim 4 is such that the first drive gear always meshes with one of the drive gears on the second traveling speed change shaft, The idle gear is always meshed with another one of the drive gears on the second traveling speed change shaft.

[0007] In the invention according to claim 1, 2, or 3, the invention according to claim 5 is characterized in that both the travel input shaft and the second travel speed change shaft are cylindrical, And a PTO transmission shaft is disposed through the transmission input shaft, and the means according to the invention according to claim 6 is arranged such that the traveling input shaft is disposed substantially at the center in the left-right direction of a transmission housing. The first traveling speed change shaft is distributed to one of the left and right sides, and the traveling output shaft is distributed to the other side in the left and right direction. Further, in the invention according to claim 6, means taken by the invention according to claim 7 is:
A power output gear is provided on the travel output shaft in conjunction with the front wheels, and the travel output shaft is disposed below the first travel speed change shaft.

[0008] In the invention according to claim 2 or 3, the means according to the invention according to claim 8 is that the first clutch device is provided with a synchronizer,
The means according to the ninth aspect of the present invention is such that the first clutch device and the second clutch device can be selectively switched by a common first shift lever that can rotate in the front-rear and left-right directions. In the means of the invention according to claim 10, wherein the multi-stage transmission mechanism is configured to operate the third clutch device in a front-rear direction along a linear shift pattern. By performing a switching operation by a lever, the output shaft is configured to obtain a step-like multi-stage shift from a low speed stage to a high speed stage. Further, the means according to the invention according to claim 11 is characterized in that: A first transmission lever capable of selectively operating a clutch device and the second clutch device and a second transmission lever capable of selectively operating the third clutch device are provided on the housing. It is intended to support a common shift table that.

[0009]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a side view of a tractor having a transmission of the present invention, FIG. 2 is a skeleton diagram showing a housing structure and an internal structure of the transmission of the present invention, and FIG. 3 is a side view showing a clutch mechanism in a first chamber A of the clutch housing 1. FIG. 4 is a sectional view, and FIG.
5 is a side sectional view showing the speed change mechanism in the second chamber B, FIG. 5 is a developed view thereof, FIG. 6 is an internal rear view of the rear axle housing 2,
FIG. 7 shows the first shift lever 52 with respect to the tractor seat 91.
Front sectional view showing an arrangement position of the second shift lever 55 and
FIG. 8 is a perspective view showing a state in which the transmission stand 51 to which the first transmission lever 52 and the second transmission lever 55 are attached is attached to the clutch housing 1. FIG.
10 is a plan sectional view showing a mounting structure of the first speed change fork shaft 58, the second speed change fork shaft 59 and the third speed change fork shaft 60 in the second chamber B. FIG. And X in FIG. 9 showing the arrangement of each speed change fork.
FIG. 11 is a perspective view showing a mounting structure of the engaging members 61 and 62 and the urging members 63 and 64 with respect to the first speed change fork shaft 58 and the second speed change fork shaft 59;
Is a front view of a portion where the detent mechanism is provided on the bearing plate 3, and FIG. 13 is an assembled perspective view of the detent mechanism.

Referring to FIG. 1, the overall structure of a tractor as an embodiment of a work vehicle having a transmission according to the present invention will be described. First, a front frame 83 is horizontally disposed at the front of the tractor, and an engine E is disposed at the rear end. A hood 84 is mounted to cover the front frame 83 and the engine E. Bonnet 8
Inside 4, a radiator 85 is provided at the front of the engine E, and an exhaust pipe 87 extends to the outside of the engine E via a muffler 86. At the rear end of the bonnet 84, a dashboard 88 having a handle 89 is provided. At the rear portion, a seat 91 is provided between left and right fenders 90, 90 covering left and right rear wheels 78, 78. As shown in FIG. 11, a first shift lever 52 and a second shift lever 55 are provided on each of the left and right sides of the seat 91.

A front end of the clutch housing 1 is bolted to an output portion at a rear end of the engine E, and the clutch housing 1 extends rearward and passes below the seat 91. The rear axle housing 2 disposed between the wheels 78, 78 is engaged with the front end of the rear axle housing 2 by bolting to form a body frame and transmission housing of the tractor. The clutch housing 1 is formed integrally with the front housing 1F and the rear housing 1R by bolting, as shown in FIG. 2 and the like. The rear axle housing 2 houses a rear wheel differential mechanism and a rear PTO mechanism inside, and supports left and right rear axles 77, 77 on the left and right sides. Attach 78 ・ 78. On the rear axle housing 2, a hydraulic lift device 92 having a lift arm 93 for elevating and lowering a working machine mounted on the rear of the tractor is mounted. Further, a rear portion is provided to transmit the power of the engine E to the working machine. A PTO shaft 18 projects rearward from a rear cover 17 that covers the rear end of the axle housing 2.

Further, below the front frame 83,
A front axle housing 80 that houses the front wheel drive mechanism and supports the left and right front axles 81 is provided. At the outer end of each front axle 81, left and right front wheels 82
82 is attached. A front wheel power take-off case 4 is mounted on the bottom surface of the clutch housing 1, a front wheel power take-out shaft 20 extends forward from the front wheel power take-out case 4, and a front wheel differential mechanism in a front axle housing 80. Are connected via a joint shaft 79. Thus, the transmission mechanism in the clutch housing 1 allows the left and right front axles 81.
The power is transmitted to the front wheels 82 of the vehicle 81.

An outline of the internal structure of the transmission of the present invention will be described with reference to FIG. The inside of the clutch housing 1 is divided into a first chamber A and a second chamber B in the front and rear by a partition wall 1a formed substantially vertically in the front and rear part. As shown in FIG. 3, the housing forming the first chamber A is the front half of the front housing 1F and the rear housing 1R forming the clutch housing 1. The front end is open and a flange 1d is formed on the end face. As shown in FIG. 1, the rear end of the engine E is fastened by bolts. In the first chamber A, a bearing wall 1b formed integrally with the clutch housing 1 is provided, and the partition wall 1a and the bearing wall 1 are provided.
b, a cylindrical traveling input shaft 7 is supported in a substantially horizontal front and rear direction. The traveling input shaft 7 extends further forward than the bearing wall 1b, and has a clutch plate 6 fixed around the shaft at its front end.

In the first chamber A of the clutch housing 1,
The flywheel 5 directly connected to the crankshaft of the engine E is accommodated therein, and constitutes a conventional dry single-plate type main clutch mechanism between the flywheel 5 and the traveling clutch plate 6. As shown in FIG. 3, a support cylinder 76 b is attached to the front surface of the bearing wall 1 b of the clutch housing 1, and is externally fitted to the traveling input shaft 7. A release bearing 76a connected to the clutch arm 76 is slidably mounted on the support cylinder 76b in the axial direction, and a front end face thereof is in contact with a lever 5a for engaging and disengaging the main clutch mechanism. When the clutch pedal is depressed, the clutch arm 76 rotates, causing the release bearing 76a to slide forward,
When the lever 5a is pushed, the clutch plate 6 is
The main clutch is disengaged and the main clutch is disengaged. When the foot is released from the clutch pedal, the clutch arm 76, the release bearing 76a, and the lever 5a return to the illustrated positions,
The clutch plate 6 is pressed against the flywheel 5 to receive the main clutch. When the rotation is transmitted from the clutch plate 6 crimped to the flywheel 5 to the front PTO transmission shaft 13, the vibration of the flywheel 5 integrated with the engine E is directly transmitted to the front PTO transmission shaft 13.
A damper spring 6 a is interposed in the clutch plate 6 so as not to be transmitted to the transmission shaft 13.

A front PTO transmission shaft 13 is inserted into the tubular traveling input shaft 7, and its front end is connected to the traveling input shaft 7.
And is directly connected to the flywheel 5 via a fixing plate 12.

The traveling input shaft 7 and a front portion P disposed therein.
The TO transmission shaft 13 and the main clutch mechanism mainly including the flywheel 5 formed at the front end thereof can be incorporated into the first chamber A from the front end opening of the clutch housing 1 as an integral unit, By supporting the middle part of the traveling input shaft 7 through the bearing wall 1b and supporting the rear end thereof on the partition wall 1a, the assembling can be completed and the assembling work is facilitated.

The rear half of the clutch housing 1 has a rear end opened to form a flange 1e at the end face, and is bolted to a flange 2d formed at the front end of the rear axle housing 2. A bearing plate 3 is disposed in the opening at the rear end of the second chamber B, and the rear axle housing 2
(See FIG. 6 and the like) integrally formed so as to protrude into the housing at the front end thereof, and are fixedly fastened with bolts. The bearing plate 3 may be provided with a similar boss on the rear end face of the clutch housing 1 and fixedly provided. Partition wall 1a in the second chamber B
Three parallel shafts are supported between the shaft and the bearing plate 3 along the front-rear substantially horizontal direction as shafts for traveling speed change. That is, the first traveling transmission shaft 8 constantly transmitted from the traveling input shaft 7, the second traveling transmission shaft 9 opposed to the rear end of the traveling input shaft 7 on the same axis, and the propeller shaft 11 described later. The traveling output shaft 10 is connected. The second traveling speed change shaft 9 has a cylindrical shape like the traveling input shaft 7, and has a rear part P connected to the front part PTO transmission shaft 13 therein.
The TO transmission shaft 14 is inserted therethrough and is connected via a joint 95 within the shaft end 7 of the traveling input shaft 7. Rear PTO
The rear end of the transmission shaft 14 extends further rearward than the bearing plate 3 and is connected to a rear PTO clutch in the rear axle housing 2.

The three traveling transmission shafts 8, 9, and 10 constituting these transmission mechanisms are fixed to the front end of the rear axle housing 2 before bolting the clutch housing 1 to the rear axle housing 2. It is previously supported on the plate 3. The rear PTO transmission shaft 14 is inserted into the second traveling transmission shaft 9. On the other hand, inside the clutch housing 1, the traveling input shaft 7 is supported by the partition wall 1a. When the clutch housing 1 and the rear axle housing 2 are fastened, the traveling speed change shafts 8, 9, and 10 extending forward from the bearing plate 3 at the front end of the rear axle housing 2 are opened. Part from inside. When the rear end of the clutch housing 1 abuts the flange 1e on the flange 2d at the front end of the rear axle housing 2, the front ends of the first traveling speed change shaft 8 and the traveling output shaft 10 are placed in separate bearings provided on the partition wall 1a. The rear PTO transmission shaft 14 and the front end of the second traveling transmission shaft 9 naturally fit into the tubular traveling input shaft 7. In this way, the two flanges 1e are used to fasten the clutch housing 1 and the rear axle housing 2 with bolts.
The assembly of each shaft in the second chamber B is completed by simply aligning 2d.

FIG. 10 shows that each shaft 8 in the second chamber B is viewed from the front.
Looking at the arrangement structure of 9 (14) and 10, first, the traveling input shaft 7 and the second traveling transmission shaft 9 are disposed substantially at the center of the clutch housing 1 in the left-right direction. This allows
In the second chamber B, a sufficient space can be secured on the left and right of the second traveling speed change shaft 9. That is, in the present embodiment, the right side below the second traveling speed change shaft 9 (the right side when viewed from the front.
The left-right positional relationship is based on front view. The first traveling speed change shaft 8 is disposed in the space (1), and the traveling output shaft 10 is disposed in the space on the lower left side.

A support shaft 19 and a front wheel power take-out shaft 20 are supported in the front wheel power take-out case 4 mounted on the bottom surface of the clutch housing 1 in the portion where the second chamber B is formed. The traveling output shaft 1 is connected via the gear 38.
A transmission system from 0 to the front wheel power take-off shaft 20 is formed. Here, the traveling output shaft 10 is disposed at a lower level than the first traveling transmission shaft 8 as shown in FIG. 10, so that the distance between the traveling output shaft 10 and the support shaft 19 is positively reduced to the front wheel power take-out shaft 20. Transmission system can be made compact.

A front and rear first bearing wall 2b and a second bearing wall 2c shown in FIG. 2 are formed in the rear axle housing 2. A rear wheel differential mechanism 21 is provided between the two bearing walls 2b and 2c. It is arranged. A propeller shaft 1 is provided between a bearing plate 3 disposed at a front end opening of a rear axle housing 2 and a first bearing wall 2b.
As shown in FIG. 4, a front end of the propeller shaft 11 is connected to a rear end of the traveling output shaft 10 via a joint 10a disposed in the bearing plate 3. The rear end of the propeller shaft 11 protrudes rearward from the first bearing wall 2b as shown in FIG. 2, has a bevel pinion 11a formed therein, and meshes with a large bevel gear of the rear wheel differential mechanism 21.

As shown in FIG. 2, a PTO brake case 75 is fixed to the front surface of the first bearing wall 2b, and a PTO clutch case 73 is provided in front of the PTO brake case 75.
A PTO clutch plate 72 is provided at the rear end of the rear PTO transmission shaft 14 extending rearward from the bearing plate 3. PTO
The clutch case 73 is fixed to a PTO clutch shaft 15 which is provided on the same axis as the rear end of the rear PTO transmission shaft 14.
The PTO clutch plate 72 is
A hydraulic piston for engaging and disengaging the PTO is accommodated to constitute a wet multi-plate hydraulically operated PTO clutch mechanism.

A PTO brake plate 74 is mounted on a boss formed on the back of the PTO clutch case 73. The PT
In the O brake case 75, a hydraulic piston for engaging and disengaging the PTO brake plate 74 with respect to the PTO brake case 75 is accommodated.
An O-brake mechanism is configured. The hydraulic piston of the PTO brake mechanism operates only when the hydraulic piston of the PTO clutch mechanism operates in the PTO clutch disengagement direction.
The PTO brake plate 74 is operated so as to be engaged with the PTO brake case 75 so that the PTO clutch shaft 15 is braked. The PTO clutch shaft 15 is
It penetrates through the inside of the TO brake case 75, is supported by the first bearing wall 2b, further extends rearward, and is connected and fixed to the front end of the PTO counter shaft 16 which is supported by the second bearing wall 2c.

The rear end of the rear axle housing 2 is open, and the rear bearing cover 17 is fastened to the rear end opening with bolts. Second bearing wall 2c and rear bearing cover 17
, A PTO counter shaft 16 and the PTO shaft 18 are pivotally supported substantially horizontally in the front-rear direction, and are interconnected via a reduction gear train. The front end of the PTO counter shaft 16 has a second bearing wall. 2c, the PTO clutch shaft 15
Connect to the rear end.

As described above, in the transmission structure of the working vehicle having the housing structure including the clutch housing 1, the rear axle housing 2, and the front wheel power take-out case 4, the specific structure of the transmission mechanism in the second chamber B is described. Will be described with reference to FIGS. 2 and 4 to 13. As shown in FIGS. 4 and 5, an input gear 22 is fixed to a shaft end (rear end) 7 a of the traveling input shaft 7 protruding into the second chamber B from the partition wall 1 a, and the shaft end 7 a of the traveling input shaft 7 is provided. The front end of the second traveling speed-change shaft 9 is relatively rotatably supported via a needle bearing, and a thrust bearing 96 disposed in the shaft end 7a of the traveling input shaft 7 receives the front end of the second traveling speed-change shaft 9 from the second traveling speed-change shaft 9. To receive the thrust. In this way, the traveling input shaft 7 and the second traveling speed change shaft 9 are arranged on the same shaft to face each other.

As shown in FIG. 5, the second traveling speed change shaft 9 (the rear PT
A gear 23 is fixed to the front end of the first traveling speed change shaft 8 disposed parallel to the O transmission shaft 14), and is always meshed with the input gear 22. A first drive gear 24 and a second drive gear 25 are loosely mounted on the rear half of the first traveling speed change shaft 8 and either the first drive gear 24 or the second drive gear 25 is firstly moved. A first clutch device 41 with a synchronizer for engaging with the transmission shaft 8 is provided. The first clutch device 41 slides the first speed change sleeve (synchronizer sleeve) 42 back and forth with the forward and backward movement of the first speed change fork 42a, thereby connecting the first drive gear 24 to the first travel speed change shaft 8. , The second drive gear 25 can be switched to one of a position engaged with the first traveling speed change shaft 8, and a neutral position not engaged with any of them. First transmission fork 42a
As shown in FIG. 9, a first transmission fork shaft 58 is inserted between the partition wall 1a and the bearing wall 3 so as to be slidable back and forth. The first transmission fork 4 is fixed to the fork shaft 58 via a spring pin 97 so as not to rotate relatively and not to move in the axial direction.
2a slides back and forth integrally with the first transmission fork shaft 58.

The forced lubricating oil supply structure for the synchronizer is configured as shown in FIGS. 5, 6, and 9. That is, an oil reservoir 3a is formed in the bearing plate 3 supporting the rear end of the first traveling speed change shaft 8, and an oil pipe 71 communicating with the oil reservoir 3a is attached to a side surface of the bearing plate 3, and an outer wall of the rear axle housing 2 is formed. Connected to the oil hole 2e opened at the end. Then, drain oil generated by, for example, a power steering device for steering a front wheel mounted on a tractor or the above-described hydraulic lift device is introduced into the oil hole 2e through a pipe 100. In this embodiment, as shown in FIG. 6, drain oil generated in a pressure oil supply / discharge circuit 99 of a power steering cylinder 98 is used. In order to supply the lubricating oil in the rear axle housing 2 as hydraulic oil for the power steering cylinder 98 to the pressure oil supply / discharge circuit 99, a suction filter 101 is provided near the bottom in the rear axle housing 2. The sucked lubricating oil is taken out of the housing and supplied to the hydraulic oil supply / discharge circuit 99 by the hydraulic pump 102. When drain oil is introduced from the hydraulic lift device, the power steering cylinder 99 may be replaced with a hydraulic cylinder for lifting and lowering the lift arm, and the pressure oil supply / discharge circuit 100 may be replaced with a pressure oil supply / discharge circuit in the hydraulic lift device.

As shown in FIG. 5, a lubricating oil passage 8 opening at the rear end surface of the first traveling speed change shaft 8 is formed in the oil sump 3a.
a communicates with each other, and lubricating oil is forcibly supplied to a friction portion and the like of the synchronizer. The oil reservoir 3a is
A concave portion is provided on the rear surface of the cover and the cover 69 is formed. Lid 69
A relief valve 70 for setting the lubrication oil pressure is attached to
The oil pressure introduced into the oil sump 3a is reduced by the relief valve 70.
Is exceeded, the excess pressure is relieved in the rear axle housing 2 behind the bearing plate 3. In addition, oil pool 3a
As shown in FIGS. 5 and 6, the oil is supplied also to a portion requiring lubrication such as the thrust bearing 96 and the spline fitting portion on the second traveling transmission shaft 7 and the rear PTO transmission shaft 14 which are higher than the oil level OL. To provide a lubricating oil distribution function.

At the front end on the second traveling speed change shaft 9,
A first-speed drive gear 26 is fixed, and a clutch gear 26a is formed at a front end of the gear 26.
A second transmission sleeve 44 is provided between the first transmission gear 6a and the clutch gear 22a formed immediately before the rear end of the input gear 22. 43. As shown in FIG. 9, a second speed change fork shaft 59 that is slidably moved back and forth between the partition wall 1a and the bearing wall 3 is inserted into the boss portion of the second speed change fork 42a. The second speed change fork 44a is fixed to the second speed change fork shaft 59 via a spring pin 97 so as not to rotate relative to the second speed change fork shaft 59 and to move in the axial direction. I am trying to do it.

The second clutch device 43 includes a state in which the second transmission sleeve 44 is engaged with only the clutch gear 26a to separate the traveling input shaft 7 and the second traveling transmission shaft 9 from each other. Can be switched to a state in which the traveling input shaft 7 and the second traveling transmission shaft 9 are directly connected. In the former case, the rotation of the travel input shaft 7 is
After being transmitted to the first traveling speed change shaft 8 via the reduction gear trains 22 and 23, the first speed change sleeve 42 transmits the first speed change shaft 8.
The transmission is transmitted to the second traveling speed change shaft 9 by engaging one of the second drive gears 24 and 25 with the clutch. In the latter case, the rotation of the traveling input shaft 7 is directly transmitted to the second traveling transmission shaft 9, and at this time, the second traveling transmission shaft 9 rotates the traveling output shaft 10 in the body forward direction.

The second speed change fork 44a is slid forward to connect the second speed change sleeve 44 to both clutch gears 26a.
The position at which the first clutch device 41 is engaged with the second clutch device 43 (the engagement position of the second clutch device 43) is restricted only when the first clutch device 41 is in the neutral position. Thereby, the first traveling speed change shaft 8 is in the idling state, and the second traveling speed change shaft 9 directly driven by the traveling input shaft 7 does not enter the double power transmission state. Conversely, the first clutch device 41 can set either the first drive gear 24 or the second drive gear 25 into engagement with the first traveling speed change shaft 8 because the second speed change sleeve 44 is engaged with the clutch gear 26a. Only the case where the gear is engaged with the second clutch device 43 (neutral position of the second clutch device 43) is restrained. Thereby, the traveling input shaft 7
Thus, transmission from the first transmission gearshift shaft 8 to the second traveling gearshift shaft 9 is ensured. The restraint mechanism between the first speed change sleeve 42 and the second speed change sleeve 44 will be described in detail later in the description of the relationship between the second speed change lever 55 and the first speed change lever 52 and the speed change mechanism in the second chamber B. I do.

On the second traveling speed change shaft 9, in order from the front to the rear, the first speed drive gear 26, the third speed drive gear 27, and the second speed drive gear 2 having the clutch gear 26a attached thereto.
The eighth and fourth speed drive gears 29 are fixed. Then, on the front traveling output shaft 10, in order from the front to the rear,
The first-speed driven gear 31, the third-speed driven gear 32, the second-speed driven gear 33, and the fourth-speed driven gear 34 idle and rotate between the first-speed driven gear 31 and the third-speed driven gear 32. , And spline hubs 35 and 36 are respectively disposed between the second speed driven gear 33 and the fourth speed driven gear 34 and fixed to the traveling output shaft 10. 1st speed driven gear 31, 3rd speed driven gear 3
The second and second speed driven gears 33 and the fourth speed driven gear 34 are respectively
A first-speed drive gear 26 fixed on the second traveling transmission shaft 9;
The driving gear 27 for the third speed, the driving gear 28 for the second speed, and the driving gear 29 for the fourth speed are always meshed.

Further, the fourth speed drive gear 29 fixed on the second traveling speed change shaft 9 meshes with the fourth speed driven gear 34 on the traveling output shaft 10 and at the same time, the fourth speed driving gear 29 The gear 24 is also always meshed with one drive gear 24, and the two gears 24 and 29 form a forward rotation reduction gear train. First clutch device 41
When the first drive gear 24 is engaged with the first travel transmission shaft 8, the power from the first drive gear 24 is transmitted from the fourth speed drive gear 29 to the second travel transmission shaft 9, The traveling speed change shaft 9 causes the traveling output shaft 10 to rotate at a reduced speed in the body forward direction as compared with the case where the above-described second clutch device 43 is operated.

An idle gear 37 is connected to the driven gear 32 for the third speed, and always meshes with the second drive gear 25 on the first traveling speed change shaft 8 to form a reverse gear train. When the first clutch device 41 engages the second drive gear 25 with the first traveling speed change shaft 8, the power from the second drive gear 25 is supplied to the idle gear 37, the third speed driven gear 32, and the third speed gear. The transmission is transmitted to the second traveling speed change shaft 9 via the drive gear 27, and at this time, the second traveling speed change shaft 9 rotates the traveling output shaft 10 in the body backward direction.

Clutch gears 31a and 32a are formed on the surfaces of the first speed driven gear 31 and the third speed driven gear 32, which are loosely fitted on the traveling output shaft 10 and face the spline hub 35, respectively. The spline hub 35 is mounted on the front third speed change sleeve 47 installed on the hub 35.
Are formed so that they cannot rotate relative to each other and are slidably fitted in the axial direction, and can be engaged with the clutch gears 31a and 32a. A rear third transmission fork 48a is engaged with an annular groove formed on the outer periphery of the front third transmission sleeve 48. Similarly, the second speed driven gear 33
The clutch gears 33a and 34a protrude from the surfaces of the driven gears 34 and the fourth speed 34 facing the spline hub 36, respectively. The rear third speed change sleeve 48 mounted on the spline hub 36 is fitted to the spline hub 36 so as to be non-rotatable and slidable in the axial direction, and is fitted to the clutch gears 33a and 34a. Meshable internal teeth are formed. An annular groove formed on the outer periphery of the rear third speed change sleeve 48 fits the rear third speed change fork 4
8a is locked.

As shown in FIG. 9, the bosses of the front third transmission fork 47a and the rear third transmission fork 48a have
A common third speed change fork shaft 60 is inserted. Here, the front third speed change fork 47a is fixed to the third speed change fork shaft 60 via a spring pin 97 so as not to rotate relative to the third speed change fork and to be unable to move in the axial direction. The other spring pin 97 implanted in the speed change fork shaft 60 and the front third speed change fork shaft 60 are rotatable. Thereby, at the time of assembling the traveling transmission mechanism, the front third transmission fork 47
a and the rear third transmission fork 48a are easily locked to the front third transmission sleeve 47, respectively.

By the shift operation of the first shift lever 52 described later, the front third shift fork 47a, the rear third shift fork 48a, and the third shift fork shaft 60 move integrally in the axial direction. The third transmission sleeve 47 and the rear third transmission sleeve 48 slide integrally back and forth. That is, on the traveling output shaft 10, the front third transmission sleeve 47 and the clutch gears 31a and 32a on both sides thereof, and the rear third transmission sleeve 48 and the clutch gears 3 on both sides thereof.
The third clutch devices 45 and 46 are constituted by 3a and 34a, and both the first and second speed change sleeves 47 and 48 slide simultaneously, so that the first speed position, the second speed position, the third speed position, and the fourth speed position are achieved. The position is switched to four positions. First, in the first gear position,
The front third speed change sleeve 47 couples the clutch gear 31a of the first speed driven gear 31 with the spline hub 35, and the rear third speed change sleeve 48 includes only the clutch gear 33a of the second speed driven gear 33. Is engaged. That is, the first-speed driven gear 31 is engaged with the traveling output shaft 10, and the rotation of the second traveling transmission shaft 9 is transmitted to the traveling output shaft 10 via the first-speed gear trains 26 and 31.

Next, at the second speed position (the position shown in FIG. 5),
The front third speed change sleeve 47 meshes only with the spline hub 35, and the rear third speed change sleeve 48 connects the clutch gear 33 a of the second speed driven gear 33 and the spline hub 36 to form a second speed driven gear. 33 is the traveling output shaft 1
0, and the rotation of the second traveling transmission shaft 9 is transmitted to the traveling output shaft 10 via the second-speed gear trains 28 and 33.

In the third speed position, the front third speed change sleeve 47
Are engaged with the spline hub 35 and the clutch gear 32a of the third-speed driven gear 32, and the rear third speed change sleeve 48 is engaged only with the spline hub 36, so that the third-speed driven gear 32 The rotation of the second traveling speed change shaft 9 is transmitted to the traveling output shaft 10 via the third-speed gear trains 27 and 32.

In the fourth speed position, the front third speed change sleeve 47 engages only with the clutch gear 32a of the third speed driven gear 32 and the rear third speed change sleeve 48.
Is engaged with the spline hub 36 and the clutch gear 34a of the fourth-speed driven gear 34, the fourth-speed driven gear 34 is engaged with the traveling output shaft 10, and the rotation of the second traveling transmission shaft 9 Is transmitted to the traveling output shaft 10 via the gear trains 29 and 34.

Next, the transmission structure from the traveling speed change mechanism in the second chamber B to the front wheel power take-out shaft 20 will be described with reference to FIG. A front wheel drive gear 30 is fixed on the traveling output shaft 10 along the partition 1a at the front end of the second chamber B. Then, the second chamber B is opened from the bottom opening of the clutch housing 1.
The support shaft 19 installed on the front wheel power take-out case 4 is inserted therein, and the gear 38 loosely fitted on the support shaft 19 always meshes with the front wheel drive gear 30. The gear 38 always meshes with a front wheel input gear 39 fixed to the front wheel power take-out shaft 20 which is supported in the front wheel power take-out case 4. Further, a spline hub 40 is fixed on the front wheel power take-off shaft 20, and a front wheel drive switching sleeve 50 slides in the axial direction between the spline hub 40 and a clutch gear 39a formed on the front wheel input gear 39. I do. The front wheel drive switching sleeve 50 is switched to a state in which only the spline hub 40 is engaged and a state in which the spline hub 40 and the clutch gear 39a are connected by lever operation or the like. In the former state, the front wheels are not driven, and the work vehicle (tractor) is driven only by the rear wheels 78. When the latter state is reached, power transmission from the traveling transmission mechanism in the second chamber B to the front wheels 82 is performed. The work vehicle (tractor) is driven by four wheels.

Next, the mounting structure of the first (main) transmission lever 52 and the second (sub) transmission lever 55 as operating members of the traveling transmission mechanism in the second chamber B, and these levers and the traveling transmission mechanism The link mechanism in the second chamber B between the two will be described with reference to FIGS. Note that, in FIG. 8, the arrow F points forward of the aircraft.

First, as shown in FIG. 7, a first shift lever 52 and a second shift lever 55 are disposed on the left and right sides of the seat 91, respectively. These levers 52 and 55 are provided between the fender 20 of the rear wheel 78 and the seat 91 and guide plates 94L and 55L.
The gears are inserted into the guide grooves G1 and G2 provided in the 94R, and are supported on the left and right sides of the transmission 51 installed on the upper surface of the second chamber B forming portion of the clutch housing 1, respectively. Gearbox 5
As shown in FIG. 8, reference numeral 1 is attached so as to cover a window 1c formed on the upper surface of the clutch housing 1.

As shown in FIG. 8, the first shift lever 52 has a base portion which can be linearly shifted to the first, second, third and fourth speed positions set in the I-shaped lever guide groove G1. Shaft 5, which is mounted on the left side wall of the transmission 51
3 is fixed to the outer end. The second shift lever 55 is fitted into the right side wall of the shift base 51 so as to be able to shift to the forward low speed position L, the reverse position R, the neutral position N, and the high forward speed position H set in the h-shaped lever guide groove G2. A ball portion 56 is fixed to the base end of the two-speed shift lever 55, and is received at the right corner of the transmission 51. An operating rod 54 is fixedly mounted on the inner end of a rotating shaft 53 interlocked with the first transmission lever 52 in the transmission base 51, and an operation rod 57 is provided diagonally below the spherical portion 56 of the second transmission lever 55. Is stretched.

As shown in FIGS. 8 to 10, a first speed change fork shaft 58 and a second speed change fork shaft 59 are provided in the upper right corner just below the window hole 1c in the second chamber B of the clutch housing 1. The third speed change fork shaft 60 is disposed in the upper left corner in the front-rear direction, and is pivotally supported between the partition wall 1a and the bearing plate 3 so as to be slidable in the front-rear direction. The positioning is performed by a detent mechanism described later provided on the bearing plate 3. An engagement portion 47b is formed on a side surface of the front third transmission fork 47 on the third transmission fork shaft 60 (a similar engagement portion may be formed on a side surface of the rear third transmission fork 48). The distal end of the operating rod 54 is engaged with the engaging portion 47b.

On the other hand, the first speed change fork 43 and the second speed change fork shaft 59 are respectively attached to the first speed change fork shaft 58 and the second speed change fork shaft 59.
The boss portion of the second speed change fork 45 is fixed. Further, as shown in FIG. 11, a part of each upper end of the first and second speed change fork shafts 58 and 59 located immediately below the window 1c is cut horizontally. Each of the mounting surfaces 58a and 59a
The recesses formed on the lower surfaces of the engaging members 61 and 62 for engaging with the operating rod 57 are respectively installed on the a.59a and fastened with mounting bolts. , On the first and second speed change fork shafts 58 and 59.

When the transmission 51 is removed as described above, the engaging portion 4
8b and the engaging members 61 and 62, the operating rods 54 and 57 are naturally disengaged, and the first transmission lever 52 and the second transmission lever 55 are immediately separated from the transmission mechanism in the clutch housing 1. And the engaging members 61 and 62
Connects the clutch housing 1 and the rear axle housing 2 so that the first and second fork shafts 58.5 are provided in the second chamber B.
9, the window hole 1c of the clutch housing 1
And can be attached to these fork shafts 58 and 59.

In this way, the transmission base 51 on which the first transmission lever 52 and the second transmission lever 55 are attached is installed on the upper surface of the clutch housing 1, and the traveling transmission mechanism and both levers 52 and 55
When the first transmission lever 5
When the second gear 2 is shifted to the first speed position, the second speed position, the third speed position, and the fourth speed position along the guide groove G1, the third speed change fork shaft 60 slides forward and backward via the operating rod 54 and the engaging portion 47b, As described above, the front third transmission fork 47a and the rear third transmission fork 48a are
The seventh and rear third speed change sleeves 48 are switched to the first, second, third and fourth speed positions.

The second shift lever 55 shifts the operating rod 57 to the engaging member 61 of the first shift fork shaft 58 or the second shift fork shaft 5
9 to engage with any one of the engagement members 62,
When the second shift lever 55 is shifted in the front-rear direction while the operating rod 54 is engaged with the engagement member 61, the first shift sleeve 42 is rotated in the reverse direction via the first shift fork shaft 58 and the first shift fork 42a. The position is switched to three positions: a position R, a neutral position N, and a forward rotation deceleration position L. Further, when the operation lever 57 is engaged with the engagement member 62 and the second speed change lever 55 is shifted back and forth, the second speed change sleeve 44 is moved at a high speed via the second speed change fork shaft 59 and the second speed change fork 44a. Position H,
The position is switched to the neutral position N.

A concave portion formed on the upper surface of the engaging members 61 and 62, into which the operating rod 57 is fitted, is provided in the left-right direction when both the first transmission fork shaft 58 and the second transmission fork shaft 59 are in the neutral position. line up. At this time, the operating rod 57 can move between the engaging member 61 and the engaging member 62 with the shift of the second speed change lever 55 in the left-right direction along the guide groove G2. As shown in FIGS. 10 and 11, the engaging member 61 is provided with an urging member 63 for urging the operating rod 57 in the direction of the engaging member 62. Is provided with an urging member 64 for urging the operating rod 57 toward the engaging member 61. These urging members 63 and 64 are
The pins 63a and 64a, which are provided in the through holes 61a and 62a penetrating toward the concave portion for entering the operating rod 57 of the operating rod 57, and whose leading ends contact the distal end of the operating rod 57, the engaging member 6
Plug members 63b and 64b fixed to the open ends of the through holes 61a and 62a of the first and second 62, and the pins 63a and 64a
Between the plug member 63b and the plug member 63b.
springs 63c and 6 for pushing out a and 64a in the direction of the operating rod 57.
4c. When both the first transmission fork shaft 58 and the second transmission fork shaft 59 are in the neutral position, the operating rod 57 receives the urging force of the pins 63a and 64a and is located at the intermediate portion between the engaging members 61 and 62. The second shift lever 55 is located at the neutral position N of the guide groove G2. When the operating rod 57 is engaged with either the engaging member 61 or the engaging member 62, the second shift lever 55 is
10 with the ball 53 as a fulcrum against the urging force of 64c.
In this case, the rocker is swung up and down.

The detent mechanisms of the first transmission fork shaft 58, the second transmission fork shaft 59, and the third transmission fork shaft 60 will be described with reference to FIGS. 9, 12, and 13. The detent mechanism is attached to the bearing plate 3 as described above. First, as shown in FIG.
9. Holes 3b and 3 provided in bearing plate 3 to fit 9.60 inside
A groove 3c having a rectangular shape in a front view and a U-shaped cross section (see FIG. 13) is formed on the front surface of the bearing plate 3 so as to communicate with the grooves 3c and 3b.
3c and 3c are provided. In the groove 3c, the urging spring 65 and the detent ball 66 are fitted so that the detent ball 66 faces the hole 3b, and then, as shown in FIG.
Cover 67 on the front surface of the bearing plate 3 so as to cover the open portion of
・ Install 68. As shown in FIG. 13, the connecting portion 3d of each groove 3c to each hole 3b is also narrowed so that only the tip of the detent sphere 66 protrudes into the hole 3b, and the speed change fork shafts 58, 59, 60 Prevents the detent sphere 66 from falling into the hole 3b when the hole is pulled out from the hole 3c.

As shown in FIG. 9, the first transmission fork shaft 58 has three detent grooves of a reverse rotation holding groove 58b, a neutral holding groove 58c, and a normal rotation deceleration holding groove 58d from the rear to the front. The speed change fork shaft 59 has two detent holes of a normal rotation high speed holding groove 59b and a neutral holding groove 59c from the rear to the front, and the third speed change fork shaft 60 has a first speed holding groove from the rear to the front. Four detent grooves 60a, a second speed holding groove 60b, a third speed holding groove 60c, and a fourth speed holding groove 60d are provided.
The sliding of the 60 in the hole 3b allows the detent sphere 66 to be selectively fitted into each detent groove.

As described above, in the traveling speed change mechanism of the working vehicle according to the present embodiment shown in FIGS. 1 to 13, the forward low speed (forward rotation deceleration) position L and the forward high speed (Forward rotation high speed) position H, reverse (reverse rotation) position R, and neutral state N, and in the forward low speed position L, forward high speed position H, and reverse position R of the second speed change lever 55 in the speed range. By operating the first shift lever 52, the first, second, third, and fourth speeds can be set for all four speeds, and a total of eight forward speeds and four reverse speeds can be obtained. You can.

[0054]

According to the present invention, there is provided a transmission constructed between an input shaft interlocked with an engine of a work vehicle and a traveling output shaft arranged in parallel with the input shaft and interlocked with rear wheels. With such a configuration, the following effects can be obtained. First, conventionally, the forward / reverse switching mechanism and the multi-speed transmission mechanism are separately arranged in front and rear because the former is disposed on the upper transmission side and the latter is disposed on the lower transmission side. By distributing the two mechanisms to the parallel first traveling transmission shaft, second traveling transmission shaft, and traveling output shaft, the two mechanisms overlap in the front-rear direction, reducing the front-rear length of the entire transmission. Thus, a compact transmission structure for a working vehicle can be obtained. In addition, when power for driving the front wheels is taken out from the lower side of the transmission as described later, the power can be arranged as close as possible to the front wheel drive unit, and the responsiveness of the front wheel drive can be improved.

Further, the first traveling speed change shaft, the second traveling speed change shaft, and the traveling output shaft are arranged in parallel, and each gear train is formed between the respective shafts. The above-mentioned claim 1 has a structure in which the second and third clutch devices are provided.
The forward / reverse switching mechanism described above and the multi-speed transmission mechanism interlocked with it can be configured compactly, and these gear trains and each clutch device also overlap the front-back position to shorten the front-rear length of the transmission. Can be planned. Further, the second clutch device has a structure in which the input shaft and the second traveling speed change shaft are directly connected only when the first clutch device is in the non-transmission state of both the forward rotation reduction gear train and the reverse rotation gear train. In addition, it is possible to avoid the occurrence of the double power transmission state between the first traveling speed change shaft and the second traveling speed change shaft.

According to a third aspect of the present invention, the first, second, and third clutch devices are provided separately for each shaft.
More specifically, the transmission structure of the working vehicle according to claim 1 or 2 can be configured compact.

According to the third aspect of the present invention, with respect to the idle gear, the driving gear on the second traveling speed change shaft can be used as it is by configuring as in the fourth aspect. The number can be reduced.

Also, in the construction of the first, second or third aspect, the structure for disposing the PTO transmission shaft is constituted as in the fifth aspect.
The transmission shaft can use the space for the continuous cylindrical input shaft and the second traveling speed change shaft as it is, and it is not necessary to provide the space for the PTO transmission shaft separately from the space for the traveling transmission. Transmission can be configured.

Further, the arrangement of the traveling input shaft, the first traveling speed change shaft, the second traveling speed change shaft, and the traveling output shaft as the traveling transmission is configured as in claim 6.
In the housing, the traveling input shaft and the second traveling speed change shaft are disposed at substantially the center in the left-right direction, so that a sufficient space for disposing the shaft and gears can be secured on the left and right sides thereof,
The first traveling speed change shaft, the traveling output shaft, and the first traveling speed changing shaft, and the traveling output shaft are distributed and disposed in the space inside the compact housing. An effective transmission arrangement structure that allows the gears to mesh with each other can be provided.

According to the sixth aspect of the present invention, the traveling output shaft, on which the power take-out gear for driving the front wheels is fixed, is provided for the front wheel power attached to the lower end of the housing. It can be closer to the take-out part, which contributes to the downsizing of the front-wheel power take-out part.

According to the eighth aspect of the present invention, the engagement of the first clutch device becomes smooth, the operability is improved, and the shift shock is reduced. Can be achieved.

According to the ninth aspect of the present invention, the first clutch device and the second clutch device can be selectively operated by one common first transmission lever, and the number of parts can be reduced. In addition, the third clutch device for switching the multi-stage transmission mechanism can be switched by rotating one of the second transmission levers in one direction in the front-rear direction. Operation is possible, and operation is easier than a shift pattern combining a plurality of rotation directions. With regard to the support structure of the first shift lever and the second shift lever, the first shift lever and the second shift lever are supported by a common shift stand installed in the transmission housing by being configured as in claim 11. As a result, assembling and disassembling are easier as compared with a configuration in which each is directly mounted and supported on the housing. Further, the processing of the housing is facilitated, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a side view of a tractor having a transmission according to the present invention.

FIG. 2 is a skeleton diagram showing a housing structure and an internal structure of the transmission of the present invention.

FIG. 3 is a side sectional view showing a clutch mechanism in a first chamber A of the clutch housing 1.

FIG. 4 is a side sectional view showing a speed change mechanism in a second chamber B of the clutch housing 1.

FIG. 5 is a development view of the same.

6 is an internal rear view of the rear axle housing 2. FIG.

FIG. 7 shows a first shift lever 5 with respect to a tractor seat 91;
FIG. 5 is a front sectional view showing an arrangement position of a second and second shift lever 55.

FIG. 8 is a perspective view showing a state where the transmission stand 51 to which the first transmission lever 52 and the second transmission lever 55 are attached is attached to the clutch housing 1.

FIG. 9 is a plan sectional view showing a mounting structure of a first transmission fork shaft 58, a second transmission fork shaft 59, and a third transmission fork shaft 60 in a second chamber B of the clutch housing 1.

FIG. 10 is a sectional view taken along line XX in FIG. 9 showing the arrangement of the first shift lever 52, the second shift lever 55, and each shift fork.

FIG. 11 is a perspective view showing a mounting structure of engaging members 61 and 62 and biasing members 63 and 64 to first and second speed change fork shafts 59 and 60;

FIG. 12 is a front view of a portion of the bearing plate 3 where a detent mechanism is provided.

FIG. 13 is an assembled perspective view of the detent mechanism.

[Explanation of symbols]

 A first chamber B second chamber E engine G1 guide groove (I type) G2 guide groove (h type) 1 clutch housing 1a partition wall 1c window hole 2 rear axle housing 3 bearing plate 3a oil reservoir (lubricating oil distribution section) 7 traveling Input shaft 8 First traveling speed change shaft 9 Second traveling speed change shaft 10 Traveling output shaft 14 Rear PTO transmission shaft 20 Front wheel power take-out shaft 21 Rear wheel differential mechanism 24 First drive gear 25 Second drive gear 26 First speed drive gear 27 Third speed drive gear 28 Second speed drive gear 29 Fourth speed drive gear 30 Front wheel input gear (front wheel power take-out gear) 31 First speed driven gear 32 Third speed driven gear 33 Second speed driven gear 34 Fourth speed driven gear 37 Idle gear 41 First Clutch device 43 Second clutch device 45 Third clutch device 46 Third clutch device 51 Transmission stand 52 First transmission lever 55 Second transmission lever

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[Procedure amendment]

[Submission date] January 14, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 9

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 10

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Claim 11

[Correction method] Change

[Correction contents]

11. A second shift lever capable of selectively switching between the first clutch device and the second clutch device, and a first shift lever capable of switching the third clutch device. 4. The transmission for a working vehicle according to claim 2, wherein the transmission is supported by a common transmission mounted on the housing. ────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 14, 1998

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

Claims (11)

[Claims] 1. A transmission configured between a traveling input shaft interlocked with an engine of a work vehicle and a traveling output shaft disposed in parallel with the traveling input shaft and interlocked with rear wheels. A first traveling speed change shaft always driven by the traveling input shaft is provided in parallel with the traveling output shaft, and a second traveling speed changing shaft parallel to the first traveling speed change shaft is provided on the same axis as the traveling input shaft so as to face the traveling input shaft. A forward / reverse switching mechanism is configured between the first traveling speed change shaft and the second traveling speed change shaft, and a multi-speed transmission is interlocked with the forward / reverse rotation switching mechanism between the second traveling speed change shaft and the traveling output shaft. A transmission for a work vehicle, comprising a mechanism. 2. A transmission configured between a traveling input shaft interlocked with an engine of a work vehicle and a traveling output shaft disposed parallel to the traveling input shaft and interlocked with rear wheels. A first traveling speed change shaft always driven by the traveling input shaft is provided in parallel with the traveling output shaft, and a second traveling speed changing shaft parallel to the first traveling speed change shaft is provided on the same axis as the traveling input shaft so as to face the traveling input shaft. A forward reduction gear train and a reverse rotation gear train between the first traveling transmission shaft and the second traveling transmission shaft, and a plurality of reduction gear trains between the second traveling transmission shaft and the traveling output shaft. A first clutch device, which can select one of a forward rotation reduction gear train and a reverse rotation gear train to transmit from the first traveling speed change shaft to the second traveling speed change shaft; When both gear trains are in the non-transmission state, the traveling input shaft and the second traveling transmission shaft can be directly connected. A working second clutch device, and a third clutch device capable of selecting one of a plurality of reduction gear trains and transmitting power from the second traveling speed change shaft to the traveling output shaft. transmission. 3. A transmission configured between a traveling input shaft interlocked with an engine of a work vehicle and a traveling output shaft disposed parallel to the traveling input shaft and interlocked with wheels, wherein the transmission is A first traveling speed change shaft that is constantly driven by the input shaft is provided in parallel with the traveling output shaft, and a second traveling speed change shaft that is parallel to the first traveling speed change shaft is provided on the same axis as the traveling input shaft so as to face each other, On the first traveling speed change shaft, a first drive gear for driving the second traveling speed change shaft in the forward rotation direction, and an idle gear externally fitted on the traveling output shaft for idle rotation always mesh with the second traveling speed change gear. A first clutch device capable of idle-fitting a second drive gear for driving the shaft in the reverse rotation direction, and selecting one of the first and second drive gears and coupling to the first traveling speed change shaft. Provided between the travel input shaft and the second travel transmission shaft,
When both gear trains are in the non-transmission state, a second clutch device that can directly connect both shafts is provided, a plurality of drive gears are fixed on the second traveling speed change shaft, and Is that a driven gear constantly meshing with each drive gear on the second traveling speed-change shaft is idle-fitted, and a third clutch device capable of selecting one of the driven gears and coupling to the traveling output shaft is provided. A transmission for a working vehicle, characterized by: 4. The drive gear on the second travel transmission shaft while the first drive gear constantly meshes with one of the drive gears on the second travel transmission shaft. The transmission of a work vehicle according to claim 3, wherein the transmission is constantly meshed with another one of the following. 5. The transmission of a work vehicle according to claim 1, wherein the traveling input shaft and the second traveling speed change shaft are both cylindrical, and a PTO transmission shaft is disposed through both the shafts. 6. The transmission input shaft is disposed substantially at the center in the left-right direction of a transmission housing.
4. The transmission of a work vehicle according to claim 1, wherein the first traveling speed change shaft is distributed to one of the left and right sides and the traveling output shaft is distributed to the other side in the left and right direction. 7. The transmission of a work vehicle according to claim 6, wherein a power take-off gear interlocked with a front wheel is provided on the traveling output shaft, and the traveling output shaft is disposed below the first traveling speed change shaft. 8. The transmission according to claim 2, wherein the first clutch device includes a synchronizer. 9. The first clutch device and the second clutch device are linked to each other so as to be selectively operated by a common first transmission lever rotatable in the front-rear direction and the left-right direction. 3. The transmission of the working vehicle according to 3. 10. The multi-speed transmission mechanism switches the third clutch device from a low speed stage to a low speed stage by performing a switching operation by a second transmission lever operable in a front-rear direction along a linear shift pattern. 4. The transmission of a work vehicle according to claim 2, wherein a step-like multi-stage shift is obtained up to a high speed stage. 11. A first transmission lever capable of selectively operating the first clutch device and the second clutch device, and a second transmission lever capable of operating the third clutch device. 4. The transmission for a working vehicle according to claim 2, wherein the transmission is supported by a common transmission mounted on the housing.