JPH11348585A - Transmission structure for working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep horizontality of a transmission shaft connecting a PTO shaft with an input shaft of a working device and shorten entire length of a vehicle, in the working vehicle provided with the working device outside of one side in the back and forth direction of a car body. SOLUTION: This working vehicle has a differential gear device 10, an HST 20, and an engine orderly arranged from a first direction on one side in the back and forth direction of a car body to a second direction on the opposite side of this, and is equipped with a working device outside of one side of the car body. In this case, a transmission 30 constituting a running-system power transmitting mechanism is provided between the differential gear device 10 and the HST 20, a PTO shaft is projected on a housing of the HST 20, and a PTO-system power transmitting mechanism for branching and transmitting power of the PTO shaft from the running-system power transmitting mechanism is projected in the housing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission structure of a working vehicle having a working device on one side in the front-rear direction of the vehicle body and outside the vehicle body.

[0002]

2. Description of the Related Art Turning radius is reduced and operability is improved.
Further, shortening the length in the vehicle front-rear direction for cost reduction and the like is a common demand for various work vehicles. This is similarly desired for a working vehicle provided with a working device on one side outward in the vehicle longitudinal direction. In addition, for such a working vehicle, a PTO shaft and the working device It is desired that the transmission shaft connecting to the input shaft of this type be installed as horizontally as possible. This is to prevent noise at the connecting portion of the transmission shaft and to improve the durability of the connecting portion.

[0003] As a transmission structure of a working vehicle that meets such a demand, for example, Japanese Utility Model Laid-Open No. 5-56555 and Japanese Patent Laid-Open No. 2-20413 are disclosed.
No. 5 discloses a power transmission mechanism such as a pulley,
The TO shaft 103 is described as being lower than the front axle 105 and projecting from the front end surface of the front axle case (see X in FIG. 9). Those described in these publications are P
In order to secure the horizontality of the transmission shaft 104 while projecting the TO shaft 103 from the front end of the front axle case at substantially the same height as the engine drive shaft 101a, the transmission shaft 104 must be lengthened (Y in FIG. 9). As a result, the overall length of the vehicle is increased. On the other hand, if the overall length of the vehicle is to be reduced while projecting the PTO shaft 103 from the front end of the front axle case at substantially the same height as the engine drive shaft 101a, the transmission shaft must be inclined. In view of the above (see Z in FIG. 9), the configuration described above is considered in view of the fact that the durability of the transmission shaft is deteriorated.

[0004] However, according to the conventional configuration,
Since a differential gear device is interposed between the engine drive shaft (or the motor shaft of the HST) and the PTO shaft, a power transmission mechanism between the two must be configured to avoid the differential gear device. In addition, the power transmission mechanism becomes complicated, which leads to an increase in vehicle cost and a decrease in work efficiency during maintenance.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and is intended to solve a problem in the vehicle body from a first direction on one side in the front-rear direction of the vehicle body in a second direction opposite thereto. In a work vehicle provided with a differential gear device, an HST and a drive source, and a work device provided outside the vehicle body in the first direction, a transmission for connecting the PTO shaft for driving the work device and the input shaft of the work device It is an object of the present invention to provide a simple transmission structure capable of reducing the overall length of a vehicle body while maintaining the horizontality of a shaft.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an axle in a first direction, which is one side in the front-rear direction of a vehicle body, so as to drive the axle from the first direction to the opposite side. A transmission structure for a working vehicle including a differential gear device, an HST, and a driving source disposed in the vehicle body along the second direction side of the vehicle, and including a working device outward in the first direction of the vehicle body, A traveling system power transmission path for transmitting the power from the driving source to the differential gear device via the HST, and a PTO system power transmission for branching and transmitting the power from the traveling system power transmission path to the working device driving PTO shaft. In a transmission structure having a path, a casing, an input unit for receiving power from the drive source in the casing, an output unit connected to the differential gear device, the input unit, And a traveling system transmission mechanism coupling the output unit, the transmission constituting a portion of the traveling system transmission pathways, the differential gear device and HS
TST, the HST includes a housing, a hydraulic pump having a pump shaft extending in the vehicle longitudinal direction, and a hydraulic motor having a motor shaft rotating in cooperation with the hydraulic pump, A second direction end of the pump shaft extends outward from the HST housing in a second direction and is axially connected to the drive source. A first direction end of the motor shaft protrudes into the transmission casing, Connected to the input of the transmission, the PTO
A shaft is supported by the HST housing so as to extend in a first direction from the HST housing.
In the T housing, there is provided a transmission structure including a PTO transmission mechanism that connects the pump shaft and the PTO shaft to form the PTO power transmission path.

Preferably, the HST housing has a main body for housing the hydraulic pump and the hydraulic motor, and an extending portion extending from the main body to one side in the vehicle width direction,
The HST housing body has an opening on the first direction side, the HST housing extension has an opening on the second direction side, and the PTO shaft is displaced to one side in the vehicle width direction from the differential gear device. In the HST
The HST housing opening in the first direction is supported by a housing extending portion, and may be closed by a hydraulic block in which the HST oil passage is formed.

Preferably, the HST housing has a main body for housing the hydraulic pump and the hydraulic motor, and an extending portion extending from the main body to one side in the vehicle width direction,
The pump shaft and the motor shaft are arranged in substantially the same horizontal plane, and the PTO shaft is supported by the HST housing extension at a position off the differential gear device on one side in the vehicle width direction. It can be.

[0009] Preferably, the differential gear device can be housed in a transmission casing.

[0010] More preferably, the transmission casing and the HST housing can be formed integrally.

In order to improve the running stability of the vehicle by disposing a drive source below the vehicle, the transmission casing comprises a main body sandwiched between the differential gear device and the HST housing main body; An extension extending in a direction opposite to the HST housing extension in the vehicle width direction from the vehicle body, wherein the traveling system transmission mechanism is housed in the transmission casing body and the transmission The casing extending portion may include an output shaft extending in the second direction and driving the axle in the second direction, and a power transmission mechanism connecting the output shaft and the traveling system transmission mechanism. .

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1 Hereinafter, a first preferred embodiment of a transmission structure according to the present invention will be described with reference to the accompanying drawings. FIG.
FIG. 2 is a schematic side view of a front mounted mower tractor 200 to which the transmission structure according to the present embodiment is applied, and FIG. 2 is an exploded plan sectional view of the transmission structure according to the present embodiment.
FIG. 7 is a cross-sectional view taken along line AA, BB, CC line, DD line, and E in FIG. 2.

First, the front mount type mower tractor 200 will be described with reference to FIG. The more tractor 20
0 is disposed outside the vehicle body 201, the first direction side wheel 201 and the second direction side wheel 202 respectively disposed in the first and second directions of the vehicle body, and the vehicle body 201. More 2
04. Below the vehicle body 201, a differential for driving the first direction side axle 70, which constitutes the transmission structure according to the present embodiment, extends from the vehicle body front-rear direction first direction side to the opposite second direction side. Gear device 10,
An HST 20 and a drive source 90 are provided, and a transmission 30 is provided between the differential gear device 10 and the HST 20.

The driver's seat of the mower tractor 200 has a master brake pedal 211 connected to the brakes (reference numeral 205 in FIGS. 2 and 3) provided on the left and right axles so as to simultaneously brake the brakes. And turn brakes L and R (not shown) for independently operating these brakes, and a seesaw pedal 212 linked to a hydraulic pump (reference numeral 22 in FIGS. 1 to 3) in the HST 20. I have. The seesaw pedal 212 is configured such that when the toe side pedal is depressed, the speed of the vehicle is increased in the first direction, and when the heel side pedal is depressed, the speed of the vehicle is increased in the second direction. Further, a sub-shift lever 213 is provided at the driver's seat of the mower tractor 200.
And a PTO lever 214. The sub shift lever 213 is connected to the hydraulic motor 2 in the HST 20.
3 is connected. In addition, the PTO lever 214
Is provided so as to be able to swing within a predetermined interval between the first and second directions, and a switch (not shown) is turned ON / OFF according to the swing position in the first direction and the second direction. , This ON
An electromagnetic valve (not shown) is controlled by the / OFF signal, and a PTO clutch described later is turned on / off. In the drawing, reference numeral 215 denotes a suspension fulcrum of the mower 204 provided below the left and right axle cases.

Next, the transmission structure according to the present embodiment will be described. As shown in FIG. 2, the transmission structure according to the present embodiment drives a first direction side axle 70 disposed in the vehicle body from the first direction side to the second direction side. A differential gear device 10, a HST 20 and a drive source (not shown in FIG. 2) are provided, and a transmission 30 is provided between the differential gear device 10 and the HST 20. In the following description, the first direction and the second direction will be described as front and rear, respectively. In the drawing, reference numeral 71 denotes a front axle case that accommodates the front axle 70, reference numeral 80 denotes a hydraulic block in which an oil passage of the HST 20 is formed, and reference numeral 205 denotes a brake that brakes rotation of left and right axles.

The HST 20 has a housing 21, a hydraulic pump 22 and a hydraulic motor 23 housed in the housing. The HST housing 21 includes:
The hydraulic pump 22 includes a main body 21a substantially at the same position as the differential gear device 10 in the vehicle width direction, and an extending portion 21b extending from the main body 21a to one side in the vehicle width direction. The motor 23 is housed in the HST housing main body 21a. On the other hand, the HST
A PTO shaft 40 for driving the mower is provided to protrude forward from the extension of the housing. The PTO shaft 40 is disposed at a position deviated from the differential gear device 10 to one side in the vehicle width direction.

In this embodiment, the HST housing body 21a is open at the front and closed at the rear by a rear wall, while the extension 21b is closed at the front by a front wall and open at the rear. It is formed as follows. Then, the front opening of the main body 21a is closed by a hydraulic block, and the rear opening of the extending portion 21b is covered by a lid member 2 described later.
1c, so that the following effects are obtained. That is, in the configuration having the extending portion 21b in addition to the main body portion 21a, if an opening is provided at the front of both the main body portion and the extending portion, it is necessary to increase the length of the hydraulic block closing the opening in the vehicle width direction. This leads to an increase in cost due to an increase in materials. The hydraulic block is
Since a certain amount of thickness is required to secure the oil amount, the amount of material that increases by increasing the width of the block in the width direction increases. Further, the housing according to the above configuration can be easily cast by pulling out the mold of the main body part forward and pulling out the mold of the extension part backward.

The PTO shaft 40 is supported by the bearing provided on the front wall of the HST housing extension 21b and the bearing provided on the lid member 21c in a double-supported manner in the extension 21b. I have.

The hydraulic pump 22 has a pump shaft 22a extending in the front-rear direction of the vehicle body and having a rear end protruding rearward from the housing. The pump shaft 22a
Has a rear end portion that is axially connected to an engine drive shaft (not shown). On the other hand, the hydraulic motor 23 is connected to the pump shaft 22a.
And a motor shaft 23a disposed substantially in parallel with the motor shaft 23a. The motor shaft 23a has a front end extending forward from the HST housing 21 and protrudes into a transmission casing 31 described later.

Further, in this embodiment, the pump shaft 22a and the motor shaft 23a are arranged in substantially the same horizontal plane, thereby enabling the lower installation of the engine axially connected to the pump shaft 22a. Thus, the stability of the vehicle is improved by lowering the center of gravity of the vehicle. That is, the pump shaft 22a which is connected to the engine drive shaft is connected to the motor shaft 23a.
In the conventional configuration in which the engine is disposed at a higher position, the engine is disposed above the vehicle body, thereby deteriorating the stability of the vehicle due to the rise of the center of gravity of the vehicle. Such an inconvenience does not occur.

The transmission 30 includes a casing 31, an input gear 34 that constitutes a transmission input portion that receives power transmitted from the engine via the HST 20 into the casing 31, and an input gear of the differential gear device 10. Output gear 3 that constitutes a transmission output unit for transmitting power to motor 11
6 is provided. The casing 31 includes the differential gear device 10 and the HST housing main body 2.
The main body portion 31a is sandwiched between the main body portion 1a and an extension portion 31b extending from the main body portion 31a in the vehicle width direction on the other side, that is, in a direction opposite to the HST housing extension portion. The casing extension 31b is detachably attached to the casing main body 31a. The input shaft 32 and the output shaft 33 are housed in the casing body 31a, and a rear-wheel drive output shaft 50 projects rearward from the casing extension 31b.

First, the transmission path of the traveling system from the engine to the differential gear device 10 in the transmission structure configured as described above will be described with reference to FIGS. As described above, the pump shaft 22a has a rear end protruding rearward from the HST housing 21, and is axially connected to the engine output shaft via a transmission shaft and a universal joint at the protruding portion. On the other hand, the front end of the motor shaft 23a is
a of the transmission, and constitutes an input shaft 32 of the transmission which is connected to the input gear 34 so as not to rotate relatively. In the present embodiment, the motor shaft 23a and the transmission input shaft are constituted by the same shaft. However, an independent input shaft supported by the transmission casing main body 31a is provided, and the input gear 34 is attached to the input shaft. It is also possible to connect the independent input shaft and the motor shaft 23a so that they cannot rotate relative to each other by supporting the independent input shaft and the motor shaft 23a. In this case, an independent input shaft and an input gear that is supported so as not to rotate relatively form the transmission input portion.

The output gear 36 is provided on the output shaft 33 so as not to rotate relatively. The output shaft 33 is connected to the differential gear device 10 as shown in FIG.
Is supported along the vehicle body width direction. The output shaft 33 further supports a gear 35 so as not to rotate relatively. The gear 35 meshes with a gear 34 on the input shaft 32.

That is, in the present embodiment, the HST 20 including the pump shaft 22a and the motor shaft 23a, the input shaft 3
2, an input gear 34 supported by the input shaft 32 so as to be relatively non-rotatable, a gear 35 meshing with the input gear 34, a gear 35
Output shaft 33 for supporting the motor so that it cannot rotate relatively, and the output shaft 3
An output gear 36, which is provided so as to be relatively non-rotatable with the input gear 3 and meshes with the input gear 11 of the differential gear device, constitutes a traveling system transmission mechanism for transmitting the driving force from the engine to the differential gear device 10.

Next, a description will be given of a PTO-system transmission path for splitting power from the traveling-system transmission path and transmitting it to the PTO shaft with reference to FIGS. 2, 4, 6, and 7. FIG. As shown in FIG. 2, a portion of the pump shaft 22a in the HST housing 21 at a portion behind the hydraulic pump body is
The gear 41 is supported so as not to rotate relatively. The gear 41
Is engaged with the gear 43. The gear 43 is supported on the PTO shaft 40 via the clutch member 42. That is,
A gear 41 supported non-rotatably on the pump shaft 22a,
Gear 43 and clutch member 42 meshing with the gear 41
Constitute a PTO transmission mechanism for transmitting power from the pump shaft 22a to the PTO shaft 40.

In this embodiment, as shown in FIG. 2, FIG. 6, and FIG.
A brake member 45 interlocked with the clutch member 42 is provided, and when the clutch is connected, the brake is released.
The brake is operated when the clutch is disengaged. By providing such a brake member 45,
The rotation of the mower can be stopped against its inertia force at the same time as the driving force to the mower is cut off.

Next, the transmission path to the rear wheel drive output shaft 50 will be described with reference to FIGS. 2, 3 and 5. FIG.
As shown in the drawing, a first intermediate shaft 51 disposed coaxially with the output shaft 33 is supported by the transmission casing extension 31b. The end faces of the first intermediate shaft 51 and the output shaft 33 abut each other, and the connecting member 52 makes it impossible to relatively rotate around the axis. A gear 53 is supported on the first intermediate shaft 51 so as not to rotate relatively. Further, a second intermediate shaft 54 is supported by the transmission casing extending portion 31b at a position rearward of the first intermediate shaft 51 along the vehicle longitudinal direction. On the second intermediate shaft 54, a gear 55 meshing with the gear 53 and a gear 56 disposed behind the gear 55 are supported so as not to rotate relatively. The gear 56
Is a rear wheel drive output shaft 50 via a one-way clutch 58.
With the gear 57 supported by the gear. That is, in the present embodiment, the output shaft 33, the first intermediate shaft 51 connected to the output shaft so as to be relatively non-rotatable around the axis, the gears 53 and 5
The second intermediate shaft 54 connected to the first intermediate shaft via the gear 5, the gears 56 and 57, and the one-way clutch 58 constitute a power transmission mechanism to the rear wheel drive output shaft 50.

In the present embodiment, the one-way clutch 58 is interposed between the rear-wheel drive output shaft 50 and the gear 57. This is because the driving force can be transmitted to the rear wheels only when a load is applied, thereby preventing the ground from being roughened due to the slip of the rear wheels. That is, always 4
If the vehicle is driven by wheels, the turning wheel, which is a steered wheel, slips due to a difference in turning radius between the front wheel and the rear wheel during turning of the vehicle, whereby the ground is roughened. On the other hand, in the present embodiment, since the one-way clutch 58 is provided, the vehicle can be driven by the rear wheels when the front wheels slip, while preventing such inconveniences.

In the embodiment having the above-described configuration, the following effects can be obtained. That is, if the distance to the front mower tip is made the same as in the present embodiment while the PTO shaft projects forward from the front axle case at a position higher than the front axle, the PTO shaft and the mower input shaft are connected. The inclination of the transmission shaft increases (see Z in FIG. 9). If the inclination of the transmission shaft is large, the durability of the transmission shaft is deteriorated, and noise at the time of elevating and lowering the mower is caused.

On the other hand, in order to suppress the inclination of the transmission shaft, P
Protruding the TO axle forward from the front axle case at a position lower than the front axle (see X in FIG. 9) depends on the fulcrum of the work equipment lift link disposed in front of the front axle case. This is very difficult, and a PTO-based power transmission mechanism that branches the power from the traveling-system power transmission path and transmits the power to the PTO shaft becomes complicated, leading to an increase in cost and deterioration in maintenance. Further, when the PTO shaft is protruded from below the fulcrum of the lift link, the ground height of the transmission shaft becomes extremely small, so that the transmission shaft easily comes into contact with a ground object such as a stone. Is raised, the inclination angle of the transmission shaft becomes too large.

On the other hand, according to the present embodiment, the HST housing 21 located rearward of the front axle 70 is
The O-shaft 40 is projected and supported, and the pump shaft 22a and the PTO shaft 40 are connected by a gear transmission mechanism in the HST housing 21. According to such a configuration, the PTO-system power transmission mechanism that branches power from the traveling-system power transmission path and transmits the power to the PTO shaft 21 can be formed with a simple structure, and the PTO shaft 21 is located rearward of the front axle 70. Therefore, it is possible to reduce the overall length of the vehicle including the mower while suppressing the inclination of the transmission shaft connecting the PTO shaft and the mower input shaft.

In the present embodiment, the PT
Since the O-shaft 40 protrudes from the HST housing extending portion 21b, the pump shaft 22a and the motor shaft 22b can be arranged in substantially the same horizontal plane, whereby the engine connected to the pump shaft 22a can be mounted. The vehicle can be disposed below the vehicle body, and vehicle stability can be improved by lowering the vehicle center of gravity.

Further, in this embodiment, the transmission casing extending portion 31b is detachable from the transmission main body portion 31a, so that parts can be shared between the two-wheel drive vehicle and the four-wheel drive vehicle. be able to. That is, the transmission casing 31a main body is set as a standard part, and when it is necessary to take out the rear wheel driving force, the transmission casing extension 31b may be retrofitted, thereby reducing inventory management burden and vehicle specifications. The ease of change can be improved.

In the present embodiment, the HST housing main body 21a and the extending part 21b are formed integrally, but they may be formed separately as the transmission casing 31.

Embodiment 2 Hereinafter, a second preferred embodiment of the transmission structure according to the present invention will be described with reference to FIG. FIG. 8 is a developed cross-sectional plan view of the transmission structure according to the present embodiment. In the drawings, the same or corresponding members as in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the transmission structure according to the present embodiment, in the transmission structure according to the first embodiment, a casing 90 in which both are integrally formed is used instead of the transmission casing body 31a and the HST housing 21. Things.

In such a transmission structure, the same effects as in the first embodiment can be obtained, and further, the cost can be reduced by reducing the number of parts. In the present embodiment, the differential gear device 10, the traveling system transmission mechanism, the HST 20 and the PT
Since the O-system transmission mechanism is accommodated in the integrally formed casing 90, the oil passage block 90 is arranged behind the HST 20, and the gear 4 constituting the PTO-system transmission mechanism is provided.
1, the clutch member 42 and the gear 43 are arranged forward of the hydraulic pump body.

Further, in each of the above embodiments, the front mount type mower tractor has been described as an example. However, the present invention is not limited to this, and various work in which a working device is provided outside in the vehicle longitudinal direction. Can be applied to cars.

Further, in each of the above embodiments, each power transmission mechanism is constituted by a gear, but the present invention is not limited to this, and various mechanical power transmission mechanisms such as a chain can be used.

In each of the above embodiments, the differential gear device, the transmission, and the HST
Is disposed substantially at the center in the vehicle width direction, but this is in consideration of vehicle balance, and the present invention is not limited to such an arrangement. That is, as long as the positions of the constituent members in the vehicle front-rear direction are the same as those in the above order, various installation positions of these members in the vehicle width direction can be applied.

[0041]

According to the power transmission structure of the present invention, a traveling system power transmission path for transmitting the power from the driving source to the differential gear device for driving the first axle via the HST, and the traveling system power PT for driving work equipment from transmission path
In a power transmission structure of a work vehicle having a PTO system power transmission path for branch transmission of power to an O-axis, a transmission constituting a traveling system power transmission path is provided between the differential gear device and the HST, and a housing of the HST is provided in a housing of the HST. Protruding the PTO shaft, and connecting the PTO shaft and the pump shaft in the HST housing;
Since the transmission mechanism that constitutes the system power transmission path is provided, the position of the PTO shaft can be set in the second direction, whereby the transmission shaft that connects the PTO shaft and the working device input shaft is connected. It is possible to obtain a simple transmission structure capable of shortening the overall length of the vehicle while ensuring the levelness.

The HST housing has a main body for accommodating a hydraulic pump and a hydraulic motor, and an extending portion extending from the main body to one side in the vehicle width direction. The PTO shaft is protruded from the extending portion, and the opening in the first direction of the main body is closed by an HST hydraulic block. Accordingly, the length in the width direction of the hydraulic block can be reduced, and the cost can be reduced by reducing the material cost. In addition, since the HST housing has such a structure, the mold of the main body can be pulled out in the first direction and the mold of the extending portion can be pulled out in the second direction. Performance can be improved.

The HST housing has a main body for accommodating a hydraulic pump and a hydraulic motor, and an extension extending from the main body to one side in the vehicle width direction.
If the TO shaft is protruded from the extending portion and the pump shaft and the motor shaft are disposed in substantially the same horizontal plane, the vertical position of the drive source connected to the pump shaft can be lowered. Accordingly, it is possible to improve running stability due to a decrease in the center of gravity of the vehicle.

Further, if the differential gear device is configured to be housed in the transmission casing, it is not necessary to separately provide a casing for the differential gear device, and the cost can be reduced by reducing material costs.

The transmission casing and the HST housing can also be made into an integral structure, so that the cost can be reduced by reducing the material cost.

The transmission casing has a main body for accommodating a traveling-system power transmission mechanism, and an extending portion extending from the main body to the other side in the vehicle width direction. In addition to supporting the output shaft for the vehicle and having a transmission mechanism connected to the traveling system power transmission mechanism, the drive source is disposed at a lower position of the vehicle to improve the traveling stability due to the bottom center of gravity of the vehicle. While planning, the second
The four-wheel drive of the vehicle can be established by disposing the joint shaft for the direction-side axle without interfering with the drive source.

Further, if the casing main body and the extending portion are separable, the casing main body is used as a common part, and when it is necessary to take out the driving force for the second direction axle, the extension is required. It is only necessary to attach the existing part, which makes it easy to manage the stock of parts and change the specifications after the vehicle is shipped.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a front mounted mower tractor to which a first embodiment of a transmission structure according to the present invention is applied.

FIG. 2 is a developed cross-sectional plan view showing the first embodiment of the transmission structure according to the present invention.

FIG. 3 is a sectional view taken along line AA in FIG. 2;

FIG. 4 is a sectional view taken along line BB in FIG. 2;

FIG. 5 is a sectional view taken along line CC in FIG. 2;

FIG. 6 is a sectional view taken along line DD in FIG. 2;

FIG. 7 is an enlarged view of a portion E in FIG. 2;

FIG. 8 is a developed sectional plan view showing a second embodiment of a transmission structure according to the present invention.

FIG. 9 is a schematic side view showing a conventional front mount type mower tractor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Differential gear device 20 HST 21 HST housing 22 Hydraulic pump 22a Pump shaft 23 Hydraulic motor 23a Motor shaft 30 Transmission 31 Transmission casing 40 PTO shaft 50 Rear-wheel drive output shaft 70 Front axle 90 Drive source

Claims (6)

[Claims] 1. A differential arranged in a vehicle body from the first direction side to a second direction side opposite to the first direction side to drive an axle in a first direction side, which is one side in the vehicle front-rear direction. A transmission structure in a work vehicle including a gear device, an HST, and a drive source, and further including a work device outside a first direction of the vehicle body, wherein power from the drive source is transmitted through the HST to the differential gear device. A transmission system power transmission path for transmitting power to the working device driving PTO shaft from the traveling system power transmission path to the working device driving PTO shaft; An input unit that receives power from a drive source, an output unit connected to the differential gear device, and a traveling system transmission mechanism that connects the input unit and the output unit; A transmission constituting a part of a power transmission path is provided between the differential gear device and the HST. The HST includes a housing, a hydraulic pump having a pump shaft extending in the vehicle longitudinal direction, and a hydraulic pump having the same structure. A hydraulic motor having a motor shaft that rotates in operation, and a second end of the pump shaft in the HST
A first direction end of the motor shaft protrudes into the transmission casing and is connected to an input portion of the transmission; A shaft is supported by the HST housing so as to extend in a first direction from the HST housing. Further, the pump shaft and the PTO shaft are connected in the HST housing to form the PTO-based power transmission path. A transmission structure, comprising: a PTO-type transmission mechanism. 2. The HST housing has a main body that houses the hydraulic pump and the hydraulic motor, and an extension that extends from the main body to one side in the vehicle width direction. The first direction side is opened, and the HST housing extension portion is opened in the second direction side, and the PTO shaft is extended from the differential gear device to one side in the vehicle width direction to extend the HST housing. The transmission structure according to claim 1, wherein the HST housing first direction side opening is closed by a hydraulic block in which the HST oil passage is formed. 3. The HST housing has a main body that houses the hydraulic pump and the hydraulic motor, and an extending portion that extends from the main body to one side in the vehicle width direction. The motor shaft is disposed in substantially the same horizontal plane, and the PTO shaft is supported by the HST housing extension at a position off the differential gear device to one side in the vehicle width direction. The transmission structure according to claim 1. 4. The transmission structure according to claim 1, wherein the differential gear device is housed in a transmission casing. 5. The transmission structure according to claim 1, wherein the transmission casing and the HST housing have an integral structure. 6. The transmission casing,
A main body portion sandwiched between the differential gear device and the HST housing main body portion, and an extending portion extending from the main body portion in a direction opposite to the HST housing extending portion in a vehicle width direction; The traveling system transmission mechanism is housed in the transmission casing main body, and extends in the transmission casing extension in a second direction, and drives an axle in a second direction, an output shaft, and the output shaft. The transmission structure according to any one of claims 2 to 5, further comprising a power transmission mechanism that connects the traveling system transmission mechanism.