JP2000335270A - Transmission system for work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operability of a gear lever of driving and PTO systems. SOLUTION: In a multistage PTO transmission system with a clutch on a front stage, a PTO speed change shaft 29 and PTO counter shaft 34 are provided in parallel with each other. The PTO counter axis 34, to which an output from the clutch is input, has a speed change gear at intervals in the axial direction. A shift gear 32 capable of being switched on and off by a linear lever guide along the fore-and-aft direction is slidably provided on the PTO speed change shaft 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission for a work vehicle such as a tractor, which includes a traveling transmission mechanism and a PTO transmission mechanism.

[0002]

2. Description of the Related Art Conventionally, a high-low switching device and a three-stage
Traveling system transmission mechanism in which a multi-stage transmission mechanism is connected in series,
A transmission for a work vehicle including a two-stage PTO transmission mechanism is known. For example, Japanese Utility Model Application
No. 6836. In this technique, a multi-speed transmission mechanism has a lever guide including a reverse gear and a lever guide of a PTO transmission mechanism arranged on one side of a seat and arranged in front and behind the body.

[0003]

With the above construction, since the multi-stage transmission mechanism includes the reverse gear, the lever guide is H-shaped, and can be rotated not only in the front-rear direction but also in the lateral direction. Sex was inferior. Further, if the number of speed stages of the PTO transmission mechanism is increased, the lever guide must be extended to the rear of the seat, and the operability deteriorates.

[0004]

The present invention uses the following means to solve the above-mentioned problems. In a multi-stage PTO transmission having a clutch 25 at a preceding stage, a PTO transmission shaft 29 and P
A TO counter shaft 34 is provided in parallel with each other,
The output of the clutch 25 is input to the PTO counter shaft 34, and the PTO counter shaft 34 is provided with a transmission gear with an axial interval, and is linearly formed with respect to the transmission gear in the front-rear direction. A shift gear 32 which can be turned on and off by the lever guide 20b is slidably provided on the PTO transmission shaft 29.

According to claim 2, the shift gear 32 is
When the shift gear 32 is slid from one side to the other side in the axial direction, the PTO transmission device has three forward rotations, one neutral position, and one reverse rotation, and the neutral position is two. This is set in the middle of two forward rotation stages, and the reverse rotation stage is set on the opposite side of the neutral position with respect to one of the forward rotation stages.

According to a third aspect of the present invention, the PTO speed change shaft 29 is provided so as to extend over an input shaft 26 which is an output shaft of the clutch 25 and an axial center thereof.
And the input shaft 26 and the PT
A PTO counter shaft 34 is arranged in parallel with the O transmission shaft 29, and the PTO transmission mechanism is configured between the PTO transmission shaft 29 and the PTO counter shaft 34.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. 1 is a plan view of a tractor, and FIG. 2 is a PTO.
FIG. 3 is a plan view of the lever guide of the transmission lever and the lever guide of the multi-stage transmission lever, FIG. 3 is a skeleton diagram of the entire transmission, FIG. 4 is a cross-sectional side view of the transmission case, FIG. It is sectional drawing of a transmission mechanism.

As shown in FIG. 1, the tractor accommodates an engine E in a hood 1 as a working vehicle, and drives the rear wheel 3 and a rear wheel 3 by a driving force of the engine E via a transmission in a transmission case 4 described later. The front wheel 2 and the PTO shaft 6 are driven. A handle 5 is provided on a rear portion of the bonnet 1, and a column shift type forward / reverse switching lever 7 and an accelerator lever 8 protrude to the left and right sides of the handle 5. In addition, the position control lever 12 and the depth control lever 1 are located on the right wing 11R of the seat 10.
3, a PTO shift lever 15 and a multi-stage shift lever 14 are arranged on a left end 11L of the seat 10, and a floor shift type high / low switching lever 16 and a front wheel drive input / output are provided at the lower front of the seat 10. A cutting lever 17 is provided.

As shown in FIG. 2, a multi-stage speed change lever 14 and a PTO speed change lever 15 on the fender 11L are linearly guided on a guide plate 20 along the front-rear direction.
0a and 20b are opened in parallel and shifted back and forth, and a multi-speed transmission lever 14 and a PTO transmission lever 15 protrude from the lever guides 20a and 20b, respectively. Lever guide 2 of PTO shift lever 15
0b is provided with a reverse rotation preventing means so that the pin 22 cannot be easily shifted to the reverse rotation side, and the pin 22 is projected into the lever guide 20b by the biasing force of the spring 21 so that the PTO speed change lever 15 is moved to the reverse rotation position "R". The restraint is performed so that the shift cannot be performed, and the restraint is released by pulling the pin 22 so that the gear can be shifted to the reverse rotation position “R”. In this embodiment, the multi-speed transmission lever 14 is a four-speed transmission, and a neutral position is provided between the second and third speeds, and the PTO transmission lever 15 is provided with three forward rotations and one reverse rotation. However, the number and position of the shift speeds such as the first speed and the second speed are not limited.

3 and 4, a transmission case 4
The structure of the transmission provided inside the transmission case 4 will be described. In the transmission case 4, the input shaft 26, the first PTO counter shaft 34, the second transmission shaft 41, the third transmission shaft 49, and the fourth transmission shaft 56 are horizontally laid in parallel. The power from the engine E is transmitted to the input shaft 26 via the main clutch 25. The forward / reverse switching mechanism C is configured as follows at a position closer to the rear side between the first PTO counter shaft 34 and the second transmission shaft 41. That is, the first PTO counter shaft 34 is provided with a forward speed change gear 35 and a reverse speed change gear 39, and the second transmission shaft 41 is provided with an idle gear 43 meshing with the forward speed change gear 35, and the reverse speed change gear. An idle gear 42 meshing with the gear 39 via the intermediate gear 40 is provided. On a second transmission shaft 41 between the idler gears 42 and 43, a clutch slider 44 of a cone-type synchronous clutch which is not rotatable relative to the shaft 41 and is slidable in the axial direction is arranged. When the clutch slider 44 engages one of the reverse rotation gears 42 and 43 with the second transmission shaft 41 by the shift operation of the forward / reverse switching lever 7, the power of the forward / reverse rotation is transmitted to the second transmission shaft 4.
1 is transmitted.

The second transmission shaft 41 and the third transmission shaft 4
The height switching mechanism D is arranged as follows near the front side between the positions 9 and 9. That is, the second transmission shaft 41 is provided with a low-speed idler gear 45 and a high-speed idler gear 46, and the third transmission shaft 49 is provided with a fixed gear 50 meshing with the low-speed idler gear 45, and the high-speed idler gear. A fixed gear 51 that meshes with the rolling gear 46 is provided. On the second transmission shaft 41 between the idler gears 45 and 46, a clutch slider 47 that cannot rotate relative to the shaft 41 and is slidable in the axial direction is disposed to When the clutch slider 47 engages one of the idler gears 45 and 46 with the second transmission shaft 41 by the shift operation, high-low speed power is transmitted to the third transmission shaft 49.
It is configured to be transmitted to.

The third transmission shaft 49 and the fourth transmission shaft 5
6, the multi-stage transmission mechanism B is configured as follows. That is, the second transmission fixed gear 55, the first speed fixed gear 54, the fourth speed fixed gear 53,
A third-speed fixed gear 52 is provided. And the fourth transmission shaft 5
6, the fixed gears 55, 54, 5
Idling gears 60, 59, 58, 57 meshing with 3, 52 are provided. On the fourth transmission shaft 56 between the idler gears 59 and 58, a clutch slider 61 which cannot rotate relative to the shaft 56 and is slidable in the axial direction is disposed, The clutch slider 61 is linearly slid by the shift operation of
By engaging one of the four idler gears 59, 60, 57, 58 with the fourth transmission shaft 56, the first to fourth gears
So that the power up to the speed is transmitted to the fourth transmission shaft 56,
A straight-gear change type multi-speed transmission mechanism B is configured. The forward / reverse switching mechanism C, the high / low switching mechanism D, and the multi-speed transmission mechanism B are connected in series, and a traveling transmission mechanism is configured in the transmission case 4.

A PTO transmission shaft 29 parallel to the first PTO counter shaft 34 is rotatably mounted on the shaft end of the input shaft 26 so as to be relatively rotatable.
4 and the PTO transmission shaft 29, the PTO transmission mechanism A is configured as follows. That is, the first PTO counter shaft 34 is provided with a fixed gear for forward rotation 2 speed, which also serves as the fixed gear 35, a transmission gear 36 for forward rotation 1 speed, and a transmission gear 38 for reverse rotation. Are idler gears 30 meshing with the forward second speed fixed gear 35, idler gears 31 meshing with the forward first speed transmission gear 36, and idler gears meshing with the reverse rotation transmission gear 38 via the intermediate gear 33. An engagement tooth 26b that rotates integrally with the input shaft 26 is disposed at an end of the PTO transmission shaft 29 so as to be relatively rotatable. On the PTO transmission shaft 29 between the idler gears 36 and 27, a shift gear 32 that cannot rotate relative to the shaft 29 and is slidable in the axial direction is arranged, and the rotation of the PTO transmission lever 15 , The shift gear 32 is slid, and the shift gear 32 is rotated by the idle gears 30, 31, 27 and the engagement teeth 26.
b is engaged with the PTO transmission shaft 29 to transmit the power of the forward first speed, the second speed, the third speed and the reverse rotation to the PTO transmission shaft 29. The transmission mechanism A is configured.

As shown in FIG. 5, an input gear 26a and a PTO
Engaging teeth 26b are provided, and the idle gear 27 is provided between the input gear 26a and the engaging teeth 26b. A recess is formed at the center of the rear end of the input shaft 26, and the front end of the PTO transmission shaft 29 is rotatably fitted. A spline portion 29a is formed on the PTO transmission shaft 29. The engagement teeth 26b are adjacent to one side of the spline portion 29a. The idler gear 30 has a boss portion, and engagement teeth 30a are engraved at an end of the boss portion, and are adjacent to the spline portion 29a. Further, the idle gear 30
The idler gear 31 is provided on the boss portion of the motor. The idler gears 27 and 31 have engaging teeth 27a and 31 respectively.
a is engraved. The spline portion 29a has inner teeth 32a meshable with the engaging teeth 26b, 30a and outer teeth 32b, 32 meshable with the engaging teeth 27a, 31a.
The shift gear 32 having the position c is slidably fitted in the axial direction.

The input gear 26a is connected to the first PTO
The engine power is transmitted to the first PTO counter shaft 34 by meshing with the gear 37 on the counter shaft 34. The P
When the TO gearshift lever 15 is linearly shifted to slide the shift gear 32 to engage the internal teeth 32a with the engagement teeth 30a, the gear 37 is shifted from the input gear 26a of the input shaft 26 to the gear 37 →
First PTO counter shaft 34 → gear 35 → gear 30 → shift gear 32 → spline portion 29a → PTO transmission shaft 29
The power is transmitted to the PTO and the PTO shift is set to “normal forward first speed”.

Similarly, when the external teeth 32c of the shift gear 32 are meshed with the engagement teeth 31a, the gear 37
→ First PTO counter shaft 34 → Gear 36 → Gear 31 →
Shift gear 32 → spline section 29a → PTO transmission shaft 2
9 and the PTO shift is set to "normal forward second speed". Similarly, when the internal teeth 32a of the shift gear 32 mesh with the engagement teeth 26b, the PTO is transmitted from the input shaft 26 via the shift gear 32.
The transmission is transmitted to the speed change shaft 29 and the PTO speed is changed to “normal forward third speed”. Similarly, the external teeth 32b of the shift gear 32 are
Gear from the input gear 26a to the gear 37 → first P
The TO counter shaft 34 → the gear 38 → the intermediate gear 33 → the gear 27 → the shift gear 32 → the spline portion 29a → the PTO speed change shaft 29 is transmitted to make the PTO speed change “reverse (R)”.

As shown in FIG. 6, a spline collar 56a is provided on a fourth transmission shaft 56, as shown in FIG.
Are fixed so that they cannot rotate relative to each other.
Engaging teeth 57a, 60a engraved on the ends of the boss portions of the idler gears 57, 60 are adjacent to one side and the other side of 6a. The idler gears 58, 59 are provided on the respective boss portions of the idler gears 57, 60. The idler gears 58 and 59 have engaging teeth 58 respectively.
a and 59a are engraved. The spline collar 56
a has internal teeth 6 meshable with the engagement teeth 57a and 60a.
1a and the clutch slider 61 having external teeth 61b, 61c that can mesh with the engagement teeth 58a, 59a are fitted slidably in the axial direction.

Therefore, when the multi-speed transmission lever 14 is linearly shifted to slide the clutch slider 61 to engage the external teeth 61c with the engagement teeth 59a, the third transmission shaft 49 → the gear 54 → The gear 59 → the clutch slider 61 → the spline collar 56a → the fourth transmission shaft 56 is transmitted to obtain “1st speed”. Similarly, when the internal teeth 61a mesh with the engaging teeth 60a, the third transmission shaft 49 → the gear 55 →
Gear 60 → clutch slider 61 → spline collar 5
6a → transmitted to the fourth transmission shaft 56, and “2nd speed” is obtained. Similarly, when the internal teeth 61a are engaged with the engagement teeth 57b, the third transmission shaft 49 → the gear 52 → the gear 57 → the clutch slider 61 → the spline collar 56a → the fourth transmission shaft 56
"3rd speed" is obtained. Similarly, external teeth 61c
Is meshed with the engagement teeth 58b, the transmission is transmitted in the order of the third transmission shaft 49 → the gear 53 → the gear 58 → the clutch slider 61 → the spline collar 56a → the fourth transmission shaft 56, and “fourth speed” is obtained.

As shown in FIG. 3, the power transmitted to the fourth transmission shaft 56 is transmitted from a spline 56b formed at the front end of the fourth transmission shaft 56 to the universal joint 62.
The input shaft of the front differential case DF is connected to a front wheel drive input shaft 63 via a clutch slider 64 and a gear 66 which are slid from the front wheel drive input shaft 63 by the rotation of the front wheel drive on / off lever 17. Informed to 65, front wheel 2
Can be driven. In addition, the fourth transmission shaft 5
6, a pinion 56c is formed at the rear end, and the rear differential device D
Thus, the rear wheel 3 is driven through the rear differential device DR. 68 is a differential lock device, and 69 is a brake.

[0020] With this configuration, the PTO transmission mechanism is realized as a straight gear change type while achieving compactness, thereby realizing multi-stage transmission, and the transmission as a whole is downsized.

[0021]

The present invention has the following advantages because it is constructed as described above. That is, multi-stage is realized while the PTO transmission mechanism is compactly assembled, and the entire transmission is downsized. Further, when the reverse rotation stage is provided as shown in the embodiment, the operability is improved and the operability is improved. In that case, set the reverse rotation prevention means to PT
By providing the lever in the lever guide of the O transmission lever, erroneous operation can be prevented even in a straight change type.

[Brief description of the drawings]

FIG. 1 is a plan view of a tractor.

FIG. 2 is a plan view of a lever guide of a PTO transmission lever and a lever guide of a multi-speed transmission lever.

FIG. 3 is a skeleton diagram of the entire transmission.

FIG. 4 is a side sectional view of a transmission case.

FIG. 5 is a sectional view of a PTO transmission mechanism.

FIG. 6 is a sectional view of a multi-speed transmission mechanism.

[Explanation of symbols]

 Reference Signs List A PTO transmission mechanism B Multi-speed transmission mechanism C Forward / reverse switching mechanism D Height switching mechanism 4 Transmission case 10 Seat 14 Multi-speed transmission lever 15 PTO transmission lever 20a, 20b Lever guide 25 Previous clutch 29 PTO transmission shaft 32 Shift gear 34 PTO counter shaft 35 forward gear 36 forward 1st speed gear 38 reverse gear 39 reverse gear 61 clutch slider

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[Procedure amendment]

[Submission date] April 20, 2000 (200.4.2
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention] Work vehicle transmission

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission for a work vehicle such as a tractor, which includes a traveling transmission mechanism and a PTO transmission mechanism.

[0002]

2. Description of the Related Art Conventionally, a high-low switching device and a three-stage
Traveling system transmission mechanism in which a multi-stage transmission mechanism is connected in series,
A transmission for a work vehicle including a two-stage PTO transmission mechanism is known. For example, Japanese Utility Model Application
No. 6836. In this technique, a multi-speed transmission mechanism has a lever guide including a reverse gear and a lever guide of a PTO transmission mechanism arranged on one side of a seat and arranged in front and behind the body.

[0003]

With the above construction, since the multi-stage transmission mechanism includes the reverse gear, the lever guide is H-shaped, and can be rotated not only in the front-rear direction but also in the lateral direction. Sex was inferior. Further, if the number of speed stages of the PTO transmission mechanism is increased, the lever guide must be extended to the rear of the seat, and the operability deteriorates.

[0004]

The present invention uses the following means to solve the above-mentioned problems. In a multi-stage PTO transmission having a clutch 25 at a preceding stage, a PTO transmission shaft 29 and P
A TO counter shaft 34 is provided in parallel with each other,
The output of the clutch 25 is input to the PTO counter shaft 34, and the PTO counter shaft 34 is provided with a transmission gear with an axial interval, and is linearly formed with respect to the transmission gear in the front-rear direction. A shift gear 32 which can be turned on and off by the lever guide 20b is slidably provided on the PTO transmission shaft 29.

According to claim 2, the shift gear 32 is
A communication arrangement, when sliding on the other side of the shift gear 32 from one axial side, PTO transmission includes a forward rotation three stages, and one neutral position, with reverse rotation one-stage, neutral position It is set in the middle of two forward rotation stages, and a reverse rotation stage is set on the opposite side of the neutral position with one of the forward rotation stages as a boundary.

According to a third aspect of the present invention, the PTO speed change shaft 29 is provided so as to extend over an input shaft 26 which is an output shaft of the clutch 25 and an axial center thereof.
And the input shaft 26 and the PT
A PTO counter shaft 34 is arranged in parallel with the O transmission shaft 29, and the PTO transmission mechanism is configured between the PTO transmission shaft 29 and the PTO counter shaft 34.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. 1 is a plan view of a tractor, and FIG. 2 is a PTO.
FIG. 3 is a plan view of the lever guide of the transmission lever and the lever guide of the multi-stage transmission lever, FIG. 3 is a skeleton diagram of the entire transmission, FIG. 4 is a cross-sectional side view of the transmission case, FIG. It is sectional drawing of a transmission mechanism.

As shown in FIG. 1, the tractor accommodates an engine E in a hood 1 as a working vehicle, and drives the rear wheel 3 and a rear wheel 3 by a driving force of the engine E via a transmission in a transmission case 4 described later. The front wheel 2 and the PTO shaft 6 are driven. A handle 5 is provided on a rear portion of the bonnet 1, and a column shift type forward / reverse switching lever 7 and an accelerator lever 8 protrude to the left and right sides of the handle 5. In addition, the position control lever 12 and the depth control lever 1 are located on the right wing 11R of the seat 10.
3, a PTO shift lever 15 and a multi-speed shift lever 14 are arranged on a left wing 11L of the seat 10, and a floor shift type high / low switching lever 16 and a front wheel drive input / output are arranged at the lower front of the seat 10. A cutting lever 17 is provided.

As shown in FIG. 2, a multi-stage speed change lever 14 and a PTO speed change lever 15 on the fender 11L are linearly guided on a guide plate 20 along the front-rear direction.
0a and 20b are opened in parallel and shifted back and forth, and a multi-speed transmission lever 14 and a PTO transmission lever 15 protrude from the lever guides 20a and 20b, respectively. Lever guide 2 of PTO shift lever 15
0b is provided with a reverse rotation preventing means so that the pin 22 cannot be easily shifted to the reverse rotation side, and the pin 22 is projected into the lever guide 20b by the biasing force of the spring 21 so that the PTO speed change lever 15 is moved to the reverse rotation position "R". The restraint is performed so that the shift cannot be performed, and the restraint is released by pulling the pin 22 so that the gear can be shifted to the reverse rotation position “R”. In this embodiment, the multi-speed transmission lever 14 is a four-speed transmission, and a neutral position is provided between the second and third speeds, and the PTO transmission lever 15 is provided with three forward rotations and one reverse rotation. However, the number and position of the shift speeds such as the first speed and the second speed are not limited.

3 and 4, a transmission case 4
The input shaft 26, the first PTO counter shaft 34, the second transmission shaft 41, the third transmission shaft 49, and the fourth transmission shaft 56 are laid in parallel in the transmission case 4. The power from the engine E is transmitted to the input shaft 26 via the main clutch 25. A forward / reverse switching mechanism C is arranged as follows at a position closer to the rear side between the first PTO counter shaft 34 and the second transmission shaft 41. That is, the first PTO counter shaft 34 is provided with a forward speed change gear 35 and a reverse speed change gear 39, and the second transmission shaft 41 is provided with an idle gear 43 meshing with the forward speed change gear 35, and the reverse speed change gear. An idle gear 42 meshing with the gear 39 via the intermediate gear 40 is provided. On a second transmission shaft 41 between the idler gears 42 and 43, a clutch slider 44 of a cone-type synchronous clutch which is not rotatable relative to the shaft 41 and is slidable in the axial direction is arranged. When the clutch slider 44 engages one of the reverse rotation gears 42 and 43 with the second transmission shaft 41 by the shift operation of the forward / reverse switching lever 7, the power of the forward / reverse rotation is transmitted to the second transmission shaft 4.
1 is transmitted.

The second transmission shaft 41 and the third transmission shaft 4
The height switching mechanism D is arranged as follows near the front side between the positions 9 and 9. That is, the second transmission shaft 41 is provided with a low-speed idler gear 45 and a high-speed idler gear 46, and the third transmission shaft 49 is provided with a fixed gear 50 meshing with the low-speed idler gear 45, and the high-speed idler gear. A fixed gear 51 that meshes with the rolling gear 46 is provided. On the second transmission shaft 41 between the idler gears 45 and 46, a clutch slider 47 that cannot rotate relative to the shaft 41 and is slidable in the axial direction is disposed to When the clutch slider 47 engages one of the idler gears 45 and 46 with the second transmission shaft 41 by the shift operation, high-low speed power is transmitted to the third transmission shaft 49.
It is configured to be transmitted to.

The third transmission shaft 49 and the fourth transmission shaft 5
6, the multi-stage transmission mechanism B is configured as follows. That is, the second transmission fixed gear 55, the first speed fixed gear 54, the fourth speed fixed gear 53,
A third-speed fixed gear 52 is provided. And the fourth transmission shaft 5
6, the fixed gears 55, 54, 5
Idling gears 60, 59, 58, 57 meshing with 3, 52 are provided. On the fourth transmission shaft 56 between the idler gears 59 and 58, a clutch slider 61 which cannot rotate relative to the shaft 56 and is slidable in the axial direction is disposed, The clutch slider 61 is linearly slid by the shift operation of
By engaging one of the four idler gears 59, 60, 57, 58 with the fourth transmission shaft 56, the first to fourth gears
So that the power up to the speed is transmitted to the fourth transmission shaft 56,
A straight-gear change type multi-speed transmission mechanism B is configured. The forward / reverse switching mechanism C, the high / low switching mechanism D, and the multi-speed transmission mechanism B are connected in series, and a traveling transmission mechanism is configured in the transmission case 4.

A PTO transmission shaft 29 parallel to the first PTO counter shaft 34 is rotatably mounted on the shaft end of the input shaft 26 so as to be relatively rotatable.
4 and the PTO transmission shaft 29, the PTO transmission mechanism A is configured as follows. That is, the first PTO counter shaft 34 is provided with a fixed gear for forward rotation 2 speed, which also serves as the fixed gear 35, a transmission gear 36 for forward rotation 1 speed, and a transmission gear 38 for reverse rotation. Are idler gears 30 meshing with the forward second speed fixed gear 35, idler gears 31 meshing with the forward first speed transmission gear 36, and idler gears meshing with the reverse rotation transmission gear 38 via the intermediate gear 33. An engagement tooth 26b that rotates integrally with the input shaft 26 is disposed at an end of the PTO transmission shaft 29 so as to be relatively rotatable. On the PTO transmission shaft 29 between the idler gears 36 and 27, a shift gear 32 that cannot rotate relative to the shaft 29 and is slidable in the axial direction is arranged, and the rotation of the PTO transmission lever 15 , The shift gear 32 is slid, and the shift gear 32 is rotated by the idle gears 30, 31, 27 and the engagement teeth 26.
b is engaged with the PTO transmission shaft 29 to transmit the power of the forward first speed, the second speed, the third speed and the reverse rotation to the PTO transmission shaft 29. The transmission mechanism A is configured.

The details of the PTO transmission mechanism are shown in FIG.
Engaging teeth 26b are provided, and the idle gear 27 is provided between the input gear 26a and the engaging teeth 26b. A recess is formed at the center of the rear end of the input shaft 26, and the front end of the PTO transmission shaft 29 is rotatably fitted. A spline portion 29a is formed on the PTO transmission shaft 29. The engagement teeth 26b are adjacent to one side of the spline portion 29a. The idler gear 30 has a boss portion, and engagement teeth 30a are engraved at an end of the boss portion, and are adjacent to the spline portion 29a. Further, the idle gear 30
The idler gear 31 is provided on the boss portion of the motor. The idler gears 27 and 31 have engaging teeth 27a and 31 respectively.
a is engraved. The spline portion 29a has inner teeth 32a meshable with the engaging teeth 26b, 30a and outer teeth 32b, 32 meshable with the engaging teeth 27a, 31a.
The shift gear 32 having the position c is slidably fitted in the axial direction.

The input gear 26a is connected to the first PTO
The engine power is transmitted to the first PTO counter shaft 34 by meshing with the gear 37 on the counter shaft 34. The P
When the TO gearshift lever 15 is linearly shifted to slide the shift gear 32 to engage the internal teeth 32a with the engagement teeth 30a, the gear 37 is shifted from the input gear 26a of the input shaft 26 to the gear 37 →
First PTO counter shaft 34 → gear 35 → gear 30 → shift gear 32 → spline portion 29a → PTO transmission shaft 29
The power is transmitted to the PTO and the PTO shift is set to “normal forward first speed”.

Similarly, when the external teeth 32c of the shift gear 32 are meshed with the engagement teeth 31a, the gear 37
→ First PTO counter shaft 34 → Gear 36 → Gear 31 →
Shift gear 32 → spline section 29a → PTO transmission shaft 2
9 and the PTO shift is set to "normal forward second speed". Similarly, when the internal teeth 32a of the shift gear 32 mesh with the engagement teeth 26b, the PTO is transmitted from the input shaft 26 via the shift gear 32.
The transmission is transmitted to the speed change shaft 29 and the PTO speed is changed to “normal forward third speed”. Similarly, the external teeth 32b of the shift gear 32 are
Gear from the input gear 26a to the gear 37 → first P
The TO counter shaft 34 → the gear 38 → the intermediate gear 33 → the gear 27 → the shift gear 32 → the spline portion 29a → the PTO speed change shaft 29 is transmitted to make the PTO speed change “reverse (R)”.

As shown in FIG. 6, a spline collar 56a is provided on a fourth transmission shaft 56, as shown in FIG.
Are fixed so that they cannot rotate relative to each other.
Engaging teeth 57a, 60a engraved on the ends of the boss portions of the idler gears 57, 60 are adjacent to one side and the other side of 6a. The idler gears 58, 59 are provided on the respective boss portions of the idler gears 57, 60. The idler gears 58 and 59 have engaging teeth 58 respectively.
a and 59a are engraved. The spline collar 56
a has internal teeth 6 meshable with the engagement teeth 57a and 60a.
1a and the clutch slider 61 having external teeth 61b, 61c that can mesh with the engagement teeth 58a, 59a are fitted slidably in the axial direction.

Therefore, when the multi-speed transmission lever 14 is linearly shifted to slide the clutch slider 61 to engage the external teeth 61c with the engagement teeth 59a, the third transmission shaft 49 → the gear 54 → The gear 59 → the clutch slider 61 → the spline collar 56a → the fourth transmission shaft 56 is transmitted to obtain “1st speed”. Similarly, when the internal teeth 61a mesh with the engaging teeth 60a, the third transmission shaft 49 → the gear 55 →
Gear 60 → clutch slider 61 → spline collar 5
6a → transmitted to the fourth transmission shaft 56, and “2nd speed” is obtained. Similarly, when the internal teeth 61a are engaged with the engagement teeth 57b, the third transmission shaft 49 → the gear 52 → the gear 57 → the clutch slider 61 → the spline collar 56a → the fourth transmission shaft 56
"3rd speed" is obtained. Similarly, external teeth 61c
Is meshed with the engagement teeth 58b, the transmission is transmitted in the order of the third transmission shaft 49 → the gear 53 → the gear 58 → the clutch slider 61 → the spline collar 56a → the fourth transmission shaft 56, and “fourth speed” is obtained.

As shown in FIG. 3, the power transmitted to the fourth transmission shaft 56 is transmitted from a spline 56b formed at the front end of the fourth transmission shaft 56 to the universal joint 62.
The input shaft of the front differential case DF is connected to a front wheel drive input shaft 63 via a clutch slider 64 and a gear 66 which are slid from the front wheel drive input shaft 63 by the rotation of the front wheel drive on / off lever 17. Informed to 65, front wheel 2
Can be driven. In addition, the fourth transmission shaft 5
6, a pinion 56c is formed at the rear end, and the rear differential device D
Thus, the rear wheel 3 is driven through the rear differential device DR. 68 is a differential lock device, and 69 is a brake.

[0020] With this configuration, the PTO transmission mechanism is realized as a straight gear change type while achieving compactness, thereby realizing multi-stage transmission, and the transmission as a whole is downsized.

[0021]

The present invention has the following advantages because it is constructed as described above. That is, multi-stage is realized while the PTO transmission mechanism is compactly assembled, and the entire transmission is downsized. Further, when the reverse rotation stage is provided as shown in the embodiment, the operability is improved and the operability is improved. In that case, set the reverse rotation prevention means to PT
By providing the lever in the lever guide of the O transmission lever, erroneous operation can be prevented even in a straight change type.

[Brief description of the drawings]

FIG. 1 is a plan view of a tractor.

FIG. 2 is a plan view of a lever guide of a PTO transmission lever and a lever guide of a multi-speed transmission lever.

FIG. 3 is a skeleton diagram of the entire transmission.

FIG. 4 is a side sectional view of a transmission case.

FIG. 5 is a sectional view of a PTO transmission mechanism.

FIG. 6 is a sectional view of a multi-speed transmission mechanism.

[Description of Signs] A PTO-system transmission mechanism B Multi-stage transmission mechanism C Forward / reverse switching mechanism D Height switching mechanism 4 Transmission case 10 Seat 14 Multi-stage transmission lever 15 PTO transmission lever 20a, 20b Lever guide 25 Previous clutch 29 PTO transmission shaft 32 Shift gear 34 PTO counter shaft 35 Forward transmission gear 36 Forward first speed transmission gear 38 Reverse rotation transmission gear 39 Reverse transmission gear 61 Clutch slider

Claims (3)

[Claims] 1. A multi-stage PT having a clutch 25 at a front stage.
In the O transmission, a PTO transmission shaft 29 and a PTO counter shaft 34 are provided so as to extend in parallel with each other. The output of the clutch 25 is input to the PTO counter shaft 34, and the PTO counter shaft 34 is A shift gear is provided with an interval, and a shift gear 32 which can be freely turned on and off by a linear lever guide 20b along the front-rear direction is slidably provided on the PTO shift shaft 29 with respect to the shift gear. A transmission for a working vehicle, comprising: 2. The shift gear 32 has a double structure. When the shift gear 32 is slid from one side in the axial direction to the other side, the PTO transmission device includes three forward rotations, one neutral position, and a reverse rotation. 2. The vehicle according to claim 1, further comprising one stage, wherein the neutral position is set in the middle of the two forward rotation stages, and the reverse rotation stage is set on the opposite side of the neutral position from one of the forward rotation stages. Work vehicle transmission. 3. A PTO transmission shaft 29 is provided so as to extend over an axis extending from an input shaft 26 which is an output shaft of the clutch 25. The PTO transmission shaft 29 is coaxial with the input shaft 26 and is supported so as to be relatively rotatable. A PTO counter shaft 34 is arranged in parallel with the input shaft 26 and the PTO transmission shaft 29, and the PTO transmission mechanism is configured between the PTO transmission shaft 29 and the PTO counter shaft 34. The transmission for a working vehicle according to claim 1.