JP5345108B2 - Tractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tractor in which a transmission case has a shape having low vertical width, a large-diameter PTO (power take-off) clutch is reasonably disposed inside the transmission case and a PTO transmission having free transmitting specifications is facilitated to be used to obtain predetermined functions. <P>SOLUTION: A travel main shaft 21 and a PTO main shaft 71 are disposed dividedly at both side lateral positions with the shaft core of an input shaft 11 sandwiched, a travel counter shaft 22 receiving power from the travel main shaft 21 is disposed on the lower side from the travel main shaft 21, the PTO counter shaft 72 receiving power of the PTO main shaft 71 side is disposed on the lower side from the PTO main shaft 71, a PTO clutch is provided on the PTO counter shaft 72 and a PTO transmission input shaft 81 transmitting power to a PTO transmission mechanism is provided on the upper part from the PTO counter shaft 72. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  In the present invention, the power of the input shaft to which engine power is transmitted is branched into a travel drive system and a PTO drive system in the transmission case, and the power of the travel drive system is transmitted to the travel differential mechanism. The present invention relates to a tractor configured to take power out of a mission case from a PTO shaft.

  As described above, the power of the input shaft to which the engine power is transmitted is branched into the travel drive system and the PTO drive system in the transmission case, and the power of the travel drive system is transmitted to the travel differential mechanism, and the PTO drive system As a tractor configured to extract the motive power from the PTO shaft to the outside of the transmission case, those described in [1] or [2] below are known.

[1] An input shaft to which engine power is transmitted via the main clutch is provided, and the power transmitted to the input shaft is transmitted to a transmission shaft disposed at a position shifted below the input shaft. It is configured to branch and transmit from the shaft to the left and right traveling drive system and the PTO drive system, and the clutch of the PTO drive system is disposed on the rear side of the differential device at the rear of the fuselage (see Patent Document 1, for example) .
[2] A travel system input shaft configured such that an input shaft to which engine power is transmitted is turned on and off by an on / off operation of a main clutch disposed on the upper side in the transmission direction, and on / off of the main clutch Consists of a PTO system input shaft configured to transmit engine power regardless of operation and a concentric inner / outer double shaft, taken out from each of the inner and outer shafts A configuration in which power is branched and transmitted to a traveling drive system and a PTO drive system in a transmission case (see, for example, Patent Document 2).

JP-A-6-46606 (see paragraph numbers [0008] and [0011], FIG. 2, FIG. 3 and FIG. 5) Japanese Patent Laying-Open No. 2005-36891 (see paragraph numbers [0014], [0015], [0018], FIG. 3)

In the conventional device described in [1] above, the traveling drive system and the PTO drive system are distributed to the left and right inside the mission case, thereby attempting to configure the mission case without extremely increasing the vertical width. Is. However, the transmission mechanisms of the traveling drive system and the PTO drive system provided in the transmission case branch from the transmission shaft, which is temporarily shifted downward from the input shaft to which engine power is transmitted, to the left and right. Since it is configured to be transmitted, the vertical width of the transmission case can be reduced as compared with the case where the transmission mechanisms of these traveling drive system and PTO drive system are arranged one above the other. Since the transmission shaft is temporarily shifted downward from the input shaft to which engine power is transmitted, the vertical width of the transmission case tends to increase by the amount by which the transmission shaft is shifted downward. is there.
Further, in this conventional structure, since the PTO clutch is disposed on the rear side of the machine body relative to the differential device of the traveling drive system, the extension dimension of the transmission case to the rear side of the machine body is increased, and the length of the machine body is increased. Tended to be longer.

In the conventional system described in [2] above, the traveling drive system and the PTO drive system are arranged so as to be branched and transmitted right and left from the input shaft to which the engine power is transmitted. It is advantageous in that it is easy to avoid an increase in the vertical width of the transmission case as compared with a case where the transmission shaft is branched from a transmission shaft that is once shifted downward from the input shaft to which engine power is transmitted.
With this structure, in the travel drive system, a travel counter shaft is disposed below the travel main shaft that is branched from the input shaft to which engine power is transmitted to configure the main gear transmission mechanism, and the PTO drive system. Then, a PTO counter shaft is disposed below the PTO main shaft that is branched from the input shaft to which the engine power is transmitted, and the PTO clutch is connected to the PTO main shaft to which the power from the input shaft to which the engine power is transmitted. Instead, it is provided on the PTO counter shaft at a position away from the PTO main shaft.
As a result, the PTO clutch is positioned on the upper side in the transmission direction with respect to the PTO transmission, facilitating the claw replacement work of the rotary tiller when the engine is stopped, and separated from the main gear transmission mechanism. It has been devised so that it can be easily placed at a location, the diameter of the PTO clutch can be increased, and it can be applied to a model that can transmit a large torque.

With this structure, the output from the PTO clutch is configured to be input to the PTO transmission as it is, with the shaft obtained by extending the PTO counter shaft as the PTO transmission input shaft.
For this reason, if the large-diameter PTO clutch is arranged near the case outer wall in the transmission case so as to increase the separation distance from the main gear transmission mechanism, the PTO counter shaft that transmits the output from the PTO clutch The PTO transmission as a PTO transmission input shaft is provided with a transmission shaft constituting the PTO transmission only at a position closer to the center in the transmission case than the PTO transmission input shaft unless the vertical dimension of the transmission case itself is increased. There is no space to do. However, when the vertical dimension of the mission case is increased, the vehicle height under the vehicle body tends to be too low.
In addition, since the PTO shaft for finally guiding the power from the transmission case to the outside of the case has an appropriate positional relationship determined in advance from the relationship with the mounting structure of the work device equipped as an attachment, the PTO shaft Therefore, it is desirable that the position of the output shaft taken out from the PTO transmission is also concentric with or close to the PTO shaft.
From these various conditions, it is difficult to make the PTO transmission with a large number of gears and to incorporate a reverse transmission structure in the PTO transmission with the structure described above.

  The purpose of the present invention is to make the cross-sectional shape of the transmission case as small as possible in the vertical direction and to freely change the specification of the PTO transmission as a PTO transmission while placing a large-diameter PTO clutch inside the transmission case without difficulty. Provided is a tractor which can be used easily to obtain a required function and can be provided with various PTO transmission structures without requiring a design change such as a position of a PTO shaft provided in a rear stage in a mission case. There is.

In order to solve the above problems, the tractor according to the present invention has the following technical means.
[Solution 1]
As described in claim 1, the power of the input shaft to which the engine power is transmitted is branched into the traveling drive system and the PTO drive system in the transmission case, and the power of the traveling drive system is transmitted to the traveling differential mechanism. In the tractor configured to take out the power of the PTO drive system from the PTO shaft to the outside of the transmission case,
The input shaft is connected to a traveling system input shaft configured such that a driving force is interrupted by an on / off operation of a main clutch disposed on the upper side in the transmission direction, and an engine side regardless of an on / off operation of the main clutch. A PTO system input shaft configured to transmit power is composed of an inner / outer double shaft concentrically provided,
A traveling main shaft that is provided with a traveling input gear that meshes with a traveling system output gear provided on the traveling system input shaft and that transmits a driving force; and a PTO input gear that meshes with a PTO output gear provided on the PTO input shaft. And a PTO main shaft to which a driving force is transmitted, and is distributed and arranged at both lateral positions across the axis of the input shaft,
With arranging the traveling counter shaft to which power is transmitted from the driving spindle to the lower side of the traveling spindle, constitutes a gear transmission mechanism comprises a speed change gear and the traveling spindle and the travel counter shaft,
A PTO counter shaft that transmits power on the PTO main shaft side is disposed below and laterally outside the PTO main shaft, and a PTO clutch that interrupts the power to the PTO drive system is connected to the PTO counter shaft from the PTO main shaft. While preparing to be located on the rear side ,
Wherein comprising a PTO transmission input shaft for transmitting power to the PTO speed change mechanism on the upper side than the PTO counter shaft, the power input via said PTO clutch to the PTO speed change input shaft, said by shifting in the PTO transmission mechanism It is characterized by being configured to be taken out from the PTO shaft.

[Operation and effect of invention according to Solution 1]
As described above, the driving state in the so-called live PTO that can drive the PTO driving system independently even if the driving of the traveling driving system is cut off is provided concentrically with the traveling system input shaft and the PTO system input shaft. In addition, by being able to appear on the inner and outer double shafts, the space utilization efficiency in the mission case can be increased and the configuration can be made compact compared to the case where these are configured on different shafts.
And while using the traveling system input shaft and the PTO system input shaft constituted by the inner and outer double shafts in this way, the power distribution from these both input shafts to the traveling drive system and the PTO drive system is as follows: , Instead of branch transmission from the transmission shaft that is once shifted downward from the input shaft to which the engine power is transmitted, it is arranged to branch transmission right and left from the input shaft to which the engine power is transmitted. Therefore, the mission case can be made to have a shape with a smaller vertical width by avoiding an increase in the vertical width of the mission case as compared with the case where the position of the branch point is the lower transmission shaft.

In addition, the PTO clutch is provided not on the PTO main shaft to which the power from the PTO input shaft composed of the inner and outer double shafts is transmitted together with the traveling input shaft but on the PTO counter shaft at a position away from the PTO main shaft. Therefore, the PTO clutch can be increased in diameter and located at a position away from the gear transmission mechanism, and can be configured to be easily applied to a model that can transmit a large torque.
Further, since the PTO clutch is disposed on the upper side in the transmission direction than the PTO transmission, it is also useful in facilitating the claw replacement operation of the rotary tiller when the engine is stopped. That is, if the PTO clutch that interrupts the power of the PTO drive system is disposed on the lower side in the transmission direction than the PTO transmission mechanism, the PTO clutch is braked when the engine is stopped. Since the rotational position of the rotary claw of the rotary tiller cannot be changed, it may be difficult to perform claw replacement work of the rotary tiller.
On the other hand, in the present invention, since the PTO clutch is arranged on the upper side in the transmission direction relative to the PTO transmission, the rotary tillage can be performed by setting the PTO transmission on the lower side in the transmission direction to the neutral state. The rotational position of the rotary claw of the apparatus can be freely changed in a non-driven state, and there is an advantage that it is easy to perform claw replacement work.
Even when such a large-diameter PTO clutch is employed, a PTO transmission input shaft that transmits power to the PTO transmission mechanism is provided above the PTO countershaft. The PTO speed change input shaft can be disposed at a position distant from the PTO counter shaft provided with the clutch. As a result, it is easy to form a space around the PTO speed change input shaft in the mission case, and the PTO speed change device can be easily arranged using the space around the PTO speed change input shaft with less spatial restrictions. .

[Solution 2]
Another technical means of the present invention taken in order to solve the above problems, as described in claim 2, in the PTO transmission mechanism, a PTO transmission counter shaft to which the power is transmitted from the PTO speed change input shaft, a PTO transmission reverse shaft for transmitting said reverse the power transmitted from the PTO speed change input shaft to the PTO speed change counter shaft, on one side of the lateral side of the PTO speed change input shaft, arranged in distributed vertically There is a feature in this point.

[Operation and effect of invention according to Solution 2]
As described above, the PTO speed change counter shaft and the PTO speed change reversing shaft are arranged on the outer side on the lateral side of the PTO speed change input shaft. By including the PTO speed change input shaft for transmitting power to the PTO speed change mechanism, the vertical space formed on the outer side of the PTO speed change input shaft can be used effectively.
That is, as described above, the PTO shift input shaft is provided above the PTO counter shaft, the position of the PTO shift input shaft in the transmission case is shifted slightly upward, and the PTO shift input shaft is moved up and down. The PTO shift counter shaft and the PTO shift reverse shaft are divided up and down, and these PTO shift counter shafts are used as a space for arranging the PTO shift counter shaft and the PTO shift reverse shaft. And the PTO speed change reversing shaft, the space on the lateral side of the PTO speed change reversing shaft is also reduced, so that the space outside the PTO speed change input shaft in the transmission case can be used effectively, so The shaft can be arranged compactly.
Therefore, PTO gearshifts with various gearshift modes including multi-stage gearshift and forward / reverse gearshift without increasing the vertical dimension of the mission case and unnecessarily increasing the lateral width of the mission case. Even if it is an apparatus, there exists an advantage which can be arrange | positioned compactly by improving the utilization efficiency of the space in a mission case.

Overall side view of tractor Plan view around the driving section Diagram showing the transmission system Development diagram of transmission system Sectional view taken along line V-V in FIG. Sectional view taken along line VI-VI in FIG. Sectional view taken along line VII-VII in FIG. Sectional view taken along line VIII-VIII in FIG. Sectional view taken along line IX-IX in FIG. Sectional view taken along line XX in FIG. Explanatory drawing which shows the arrangement positional relationship of each axis in the cross section in the vertical direction in the mission case

  Hereinafter, an example of an embodiment of the present invention will be described based on the drawings.

[Overall structure of tractor]
FIG. 1 shows an entire side surface of a tractor having a PTO shaft drive structure according to the present invention. The tractor includes a front wheel 5 that is steered by a steering handle 4 and a main propulsion wheel that is fixed in the front and rear directions of a monobody type vehicle body that is directly connected to an engine 1, a clutch housing 2, and a transmission case 3. The rear wheel 6 is configured as a four-wheel drive type in which the rear wheel 6 is pivotally mounted.
This tractor is configured so that various working devices can be connected to a three-point link mechanism 7 provided at the rear part of the transmission case 3 so as to be able to drive up and down, and a trailer or the like can be connected to a rear hitch (not shown). .

FIG. 2 is a plan view showing the periphery of the driving unit, which includes a control unit deck 8 formed substantially flat on the upper side of the monobody type vehicle body, and a driver seat 9 is disposed on the control unit deck 8. Yes. A steering handle 4 is provided in front of the driver seat 9, and a forward / reverse switching lever 37 for operating a forward / reverse transmission mechanism 30 described later is disposed on the left side of the steering handle 4. A main clutch pedal 14 for turning on and off the main clutch 10 is disposed on the control unit deck 8 on the front side of the driver seat 9.
A main transmission lever 26 for operating a main gear transmission mechanism (corresponding to a gear transmission mechanism) 20 and a sub transmission lever 49 for operating the sub gear transmission mechanism 40, which will be described later, are arranged on the left side of the driver seat 9. On the right side of the seat 9, a PTO clutch lever 73 for turning on and off the PTO clutch 70 and a PTO speed change lever 86 for changing the speed of the PTO speed change mechanism 80 are disposed.

[Transmission mechanism]
FIG. 3 shows an outline of the transmission system. The output of the engine 1 is transmitted to the input shaft 11, and the power transmitted to the input shaft 11 is branched into the traveling drive system and the PTO drive system in the transmission case 3, and the power of the traveling drive system is transmitted to the differential mechanism 55. In addition, the power of the PTO drive system is extracted from the PTO shaft 15 to the outside of the transmission case 3.

  The input shaft 11 includes a cylindrical travel system input shaft 12 configured such that power from the engine 1 is interrupted via the main clutch 10, and the engine 1 side regardless of whether the main clutch 10 is turned on or off. PTO system input shaft that is integrally attached to the output shaft (not shown) of the engine 1 and interlocked with the output rotating body 1A that rotates about the same axis as the output shaft of the engine 1 so that the power of the engine 1 is transmitted. The input shaft 11 is configured as an inner / outer double shaft by concentrically fitting the PTO system input shaft 13 to the cylindrical traveling system input shaft 12.

[Transmission of traveling drive system]
The power branched from the travel system input shaft 12 to the travel drive system is disposed between the travel main shaft 21 and the travel counter shaft 22 and between the shuttle main shaft 31 and the shuttle counter shaft 32 of the forward / reverse transmission mechanism 30. The main gear transmission mechanism 20, the transmission operation clutch 25 for intermittently transmitting power on the lower transmission side of the traveling main shaft 21 and the traveling counter shaft 22, the forward / reverse transmission mechanism 30 for forward / reverse switching, and the auxiliary gear transmission mechanism 40, or via the creep transmission mechanism 50 for ultra-low speed work, and is transmitted to the bevel pinion gear shaft 42 which is the final transmission shaft, and is transmitted to the left and right rear wheels 6 via the differential mechanism 55. is there.
The traveling drive system is also provided with a front wheel drive mechanism 60 for transmitting the power transmitted to the bevel pinion gear shaft 42 to the front wheels 5.

  Power transmission from the input shaft 11 to the main gear transmission mechanism 20 is transmitted to a cylindrical traveling system input shaft 12 configured to be intermittently powered by the engine 1 via the main clutch 10. The traveling system input shaft 12 is provided with a traveling system output gear 12 a at the shaft end on the lower side in the transmission direction, and the traveling system output is output to the traveling input gear 21 a provided on the traveling main shaft 21 of the main gear transmission mechanism 20. The power transmission is performed with the gear 12a engaged.

The main gear transmission mechanism 20 includes four pairs of a traveling main shaft 21 to which power from the traveling system input shaft 12 is transmitted and a traveling counter shaft 22 disposed in parallel with the traveling main shaft 21. Transmission gears 21b, 21c, 21d, 21e, 23a, 23b, 23c, 23d are provided, and these transmission gears 21b, 21c, 21d, 21e, 23a, 23b, 23c, 23d are moved forward and backward by two shift sleeves 24a, 24b. A synchromesh type transmission mechanism is employed that is configured to perform selective shifting and to perform a four-step shift.
Along with this, there are provided two pairs of transmission gears 32a, 32b, 35a, 35b provided on a shuttle main shaft 31 of a forward / reverse transmission mechanism 30 to be described later and a shuttle counter shaft 32 parallel to the shuttle main shaft 31. A synchromesh transmission mechanism is employed that is configured to selectively shift the gears 32a, 32b, 35a, and 35b with a shift sleeve 36b for high and low speeds to perform a two-step shift.
Therefore, in this main gear transmission mechanism 20, four pairs of transmission gears 21b, 21c, 21d, 21e, 23a, 23b, 23c, which are provided on each of the traveling counter shaft 22 and the traveling counter shaft 22 arranged in parallel, are provided. 8 steps of high and low by four steps of shifting by selective switching of 23d and two steps of shifting by selective switching of two pairs of transmission gears 32a, 32b, 35a, 35b provided on the shuttle main shaft 31 and the shuttle counter shaft 32. It is comprised so that shifting operation of can be performed.

On the lower transmission side of the travel counter shaft 22 of the main gear transmission mechanism 20, a shift operation clutch 25 is provided for intermittently transferring power between the travel counter shaft 22 and the shuttle main shaft 31 of the forward / reverse transmission mechanism 30. Yes.
The speed change clutch 25 detects the start of speed change operation by the main speed change lever 26 by appropriate detecting means (not shown), thereby operating the shift sleeves 24a, 24b, 36b of the main gear speed change mechanism 20. The switching operation is performed so as to be intermittently performed in synchronization with the shift operation so that it is operated after the shift sleeves 24a, 24b, and 36b are operated. Is of a well-known structure linked so as to perform smoothly.
The on / off operation of the shift operation clutch 25 is performed by pressing the friction plate in the pressure oil supply state to perform the on / off operation, and the built-in biasing spring is restored along with the discharge of the supplied pressure oil. In this way, the hydraulic device is controlled by a known hydraulic device, and the hydraulic device is controlled by a control device (not shown).

The forward / reverse transmission mechanism 30 includes a shuttle main shaft 31 to which power from the travel counter shaft 22 is transmitted, a shuttle counter shaft 32 parallel to the shuttle main shaft 31, and a shuttle back shaft 33.
The shuttle main shaft 31 includes a drive rotator 31a that is rotated integrally with the shuttle main shaft 31, a forward relay gear 34a that transmits the driving force of the drive rotator 31a to the forward drive side, and a reverse that is transmitted to the reverse drive side. A relay gear 34b is provided, and a forward / reverse switching shift sleeve 36a can selectively switch the driving force transmission direction between the forward relay gear 34a and the reverse relay gear 34b.
The forward relay gear 34a is configured so that two pairs of transmission gears 32a, 32b, 35a, and 35b constituting a part of the gear stage of the main gear transmission mechanism 20 are operated in linkage. That is, the forward relay gear 34a is integrally equipped with the forward drive rotating body 34d via the cylindrical shaft portion 34c.
When the forward / reverse switching sleeve 36a is switched so as to select the forward relay gear 34a, the driving force is transmitted to the forward drive rotating body 34d. A transmission gear 35a loosely fitted to each of the shuttle main shaft 31 and the cylindrical shaft portion 34c so that the driving force transmitted to the forward drive rotating body 34d is switched between two steps of high and low and transmitted to the forward drive side. , 35b, so that either the low speed side transmission gear 35a or the high speed side transmission gear 35b can be selectively switched by the high / low speed shift sleeve 36b.

The shuttle counter shaft 32 is provided with two transmission gears 32a and 32b that mesh with the transmission gears 35a and 35b on the shuttle main shaft 31 side, and a reverse transmission gear 32c that meshes with the reverse gear 33a on the shuttle back shaft 33 side. It has.
A reverse transmission gear 34e is formed integrally with the reverse relay gear 34b on the shuttle main shaft 31 side, and a reverse driving force is transmitted from the reverse transmission gear 34e to the reverse gear 33a on the shuttle back shaft 33 side. It is constituted as follows.
In this way, the forward / reverse transmission mechanism 30 employs a synchromesh transmission mechanism configured to perform forward / reverse switching for forward / reverse switching.

The traveling power output from the shuttle counter shaft 32 of the forward / reverse transmission mechanism 30 is transmitted to the bevel pinion gear shaft 42 via the auxiliary gear transmission mechanism 40 or the creep transmission mechanism 50 for ultra-low speed operation. It is configured.
That is, the sub-gear transmission mechanism 40 includes drive rotating bodies 41 a and 41 b that are rotated integrally with the sub-transmission input shaft 41, and two pairs of sub-transmissions between the sub-transmission input shaft 41 and the bevel pinion gear shaft 42. Transmission gears 43b, 43c, 45c, 42b are provided.
The two pairs of auxiliary transmission gears 43b, 43c, 45c, and 42b are respectively provided with a first shift sleeve 44a that is individually provided between the auxiliary transmission input shaft 41 and the drive rotating bodies 41a and 41b that are rotated together. A synchromesh-type transmission mechanism that includes a second shift sleeve 44b and a third shift sleeve 46 provided between the bevel pinion gear shaft 42 and a drive rotating body 42a that is rotated integrally is adopted. Has been.

In this sub-gear transmission mechanism 40, the first shift sleeve 44a is switched to engage with the first sub-transmission gear 43b, and the second shift sleeve 44b is released from the second sub-transmission gear 43c. The bevel pinion gear shaft 42 is driven in the “low speed” state of the sub-shift by performing the switching operation so that the third shift sleeve 46 is engaged with the third sub-shift gear 45c. It is configured.
Further, the engagement of the first shift sleeve 44a with the first sub transmission gear 43b is released, the second shift sleeve 44b is switched to engage with the second sub transmission gear 43c, and the third shift sleeve 46 is operated. By performing a switching operation so as to release the engagement with the third auxiliary transmission gear 45c, the bevel pinion gear shaft 42 is moved in the “high speed” state of the auxiliary transmission via the second auxiliary transmission gear 43c and the fourth auxiliary transmission gear 42b. It is configured to drive.

The creep transmission mechanism 50 is provided with a pair of transmission gears 43a and 45a for creep transmission between the auxiliary transmission input shaft 41 and the bevel pinion gear shaft 42, and between the bevel pinion gear shaft 42 and the creep transmission shaft 51. In addition, two pairs of transmission gears 45b, 45d, 51a, 51b for creep transmission are provided.
The first shift sleeve 44a for selecting the first sub-transmission gear 43b of the sub-gear transmission mechanism 40 is selected as the selection operation of the transmission gears 43a, 45a, 45b, 45d, 51a, 51b for creep transmission. And a third shift sleeve 46 for selecting and operating the third auxiliary transmission gear 45c.
That is, the selection operation of the pair of first creep transmission gears 43a for creep transmission is performed by the operation of the first shift sleeve 44a in the direction opposite to the operation toward the first auxiliary transmission gear 43b, and the third auxiliary transmission gear 43b is operated. The operation of selecting the second creep transmission gear 45d for creep shift is performed by operating the third shift sleeve 46 in the opposite direction to the operation toward the gear 45c.
At this time, the second shift sleeve 44b is in a position to release the drive of the second auxiliary transmission gear 43c.

Near the rear end of the bevel pinion gear shaft 42, a front wheel output gear 42c to a front wheel drive mechanism 60, which will be described later, is mounted so as to be integrally rotatable. The front wheel output gear 42c transmits traveling driving force to the front wheel drive mechanism 60 via a relay gear 48 that is loosely supported in the middle of the PTO shaft 15 described later.
The bevel gear 47 at the rear end of the bevel pinion gear shaft 42 meshes with the differential gear 55a of the differential mechanism 55, and is configured to output driving power to the left and right rear wheels 6 via the differential mechanism 55. ing.

The front wheel drive mechanism 60 transmits the driving force transmitted via the relay gear 48 to the front wheel 5 via a front wheel drive shaft 64 (see FIGS. 5 to 10) via a four-wheel drive shaft 62 described later. Thus, the four-wheel drive state in which the front wheels 5 are driven and the two-wheel drive state in which the power transmission to the front wheels 5 is cut off and driven only by the rear wheels 6 are configured to be freely switchable. When driving in a turning state while driving the rear wheel 6 at a constant speed, the front wheel 5 is of a known structure configured to perform double speed driving that drives the front wheel 5 at a circumferential speed approximately twice that of the rear wheel 6. .
That is, the motive power input from the relay gear 48 is transmitted through the transmission gears 61a, 61b, 61c provided on the double speed drive shaft 61, the transmission gears 62a, 62b provided on the four-wheel drive shaft 62, and the front wheel drive clutch 63. A constant speed drive state in which straight speed constant power is transmitted through the transmission gears 61c, 61b, 62b, and a double speed drive in which double speed power for turning is transmitted through the transmission gears 61c, 61a, 62a. In this state, the front wheel drive clutch 63 can be switched. Further, the front wheel drive clutch 63 is disengaged and the power is not transmitted from either side of each of the transmission gears 62a and 62b so that the power input from the relay gear 48 is not output to the front wheel 5 side. The drive state is also switchable.
The front wheel drive clutch 63 is linked to a steering operation mechanism (not shown), and switches the front wheel drive clutch 63 from the constant speed drive state to the double speed drive state when the front wheel 5 is steered beyond a predetermined angle. When the four-wheel drive or two-wheel drive state at a constant speed is selected, the linkage operation with the steering operation mechanism is cut off, and the four-wheel drive or two-wheel drive state is selected. A selection switch (not shown) that can select either one is provided.

[PTO drivetrain transmission]
Among the input shafts 11, the PTO input shaft 13 is provided through the cylindrical travel system input shaft 12 in the front-rear direction, and the front end side is the driving force on the engine 1 side regardless of the clutch on / off operation of the main clutch 10. Is connected to an output rotator 1A to which is transmitted, and is configured to always rotate together with the output rotator 1A.
The rear end side of the PTO system input shaft 13 extends rearward from the traveling system input shaft 12, and a PTO system output gear 13a for transmitting power to the PTO drive system is provided at the rear end portion. It is provided integrally.

The power branched from the PTO input shaft 13 to the PTO drive system is transmitted to the PTO shaft 15 projecting rearward from the rear end of the transmission case 3 via the PTO clutch 70 and the PTO transmission mechanism 80. It is comprised so that.
The PTO clutch 70 is artificially turned on and off by a PTO clutch lever 73 for manual operation provided on the right side of the driver's seat 9. It is configured to be operated by pressing and entering, and cutting operation is performed when the built-in biasing spring is restored along with the discharge of the supplied pressure oil. Along with this cutting operation, a braking force is applied to the lower transmission side. The cutting operation of the PTO clutch 70 and the braking operation to the lower transmission side after the cutting operation are controlled by a known hydraulic device, and the hydraulic device is controlled by a control device (not shown). It is.

  The power from the PTO system input shaft 13 to the PTO clutch 70 is a PTO main shaft 71 having a PTO input gear 71a meshing with a PTO system output gear 13a provided at the rear end of the PTO system input shaft 13, and the PTO main shaft. 71 is transmitted through a PTO counter shaft 72 having a transmission gear 72a meshing with the 71 PTO input gear 71a.

The PTO clutch 70 is constituted by a known hydraulically operated multi-plate clutch that is turned on and off by pressure oil supply / discharge. That is, when the pressure oil is discharged, a piston member (not shown) is pushed back by an internal spring (not shown) to bring about a “clutch disengagement” state, and the supply of pressure oil causes the piston member to become an internal spring. By advancing and moving against the friction plate group, the friction plate group is pressed and brought into a “clutch engaged” state.
The power transmitted to the lower transmission side when the PTO clutch 70 is engaged is output to the PTO transmission input shaft 81 of the PTO transmission mechanism 80 via the output gear 72b provided at the transmission lower end of the PTO counter shaft 72. Is transmitted to an input gear 81a provided at an end portion on the upper transmission side.
In the clutch disengaged state of the PTO clutch 70, a part of the PTO clutch 70 is pressed against the fixed portion in the transmission case 3 through the piston member pushed back by the internal spring and is braked, and the rotation of the PTO counter shaft 72 is suppressed. As a result, the rotation on the lower transmission side is stopped.

The PTO transmission mechanism 80 includes a PTO transmission input shaft 81 to which power from the PTO counter shaft 72 is transmitted, a PTO transmission counter shaft 82 disposed in parallel with the PTO transmission input shaft 81, and a PTO transmission reverse rotation shaft 83. I have.
Drive rotation bodies 82a and 82b that rotate together with the PTO transmission counter shaft 82 are provided, and four pairs of transmission gears 81b and 81d provided on the PTO transmission input shaft 81 and the PTO transmission counter shaft 82, respectively. , 81e, 81f, 84a, 84b, 84c, 84d. These transmission gears 81b, 81d, 81e, 81f, 84a, 84b, 84c, 84d are selectively shifted forward and backward by two shift sleeves 85a, 85b. A synchromesh transmission mechanism is employed that is configured to perform a four-step shift on the shift side.

A pair of transmission gears 81c and 83a is also provided between the PTO transmission input shaft 81 and the PTO transmission reverse rotation shaft 83. The pair of transmission gears 81c and 83a is a transmission gear of the PTO transmission input shaft 81. 81c is a fixed gear, and a transmission gear 83a provided on the PTO transmission reverse rotation shaft 83 is configured to be slidable in the axial direction of the PTO transmission reverse rotation shaft 83, and is fixed to the fixed transmission gear 81c on the PTO transmission input shaft 81 side. It is configured to be detachable.
That is, when the transmission gear 83a provided on the PTO transmission reverse rotation shaft 83 is engaged with the transmission gear 81c on the PTO transmission input shaft 81 side, the transmission of the PTO transmission reverse rotation shaft 83 from the transmission gear 81c on the PTO transmission input shaft 81 side is performed. Reverse rotation power is input to the PTO transmission counter shaft 82 via the gear 83 a and the wide shift sleeve 85 a of the PTO transmission counter shaft 82.

An output gear 82c is provided at the rear end portion of the PTO speed change counter shaft 82 so as to rotate integrally therewith, and a transmission gear 86a meshing with the output gear 82c is provided on the front end side of the PTO shaft 15.
The PTO speed change mechanism 80 employs a constant mesh type speed change mechanism that shifts the shift sleeves 85a and 85b back and forth by a shift fork (not shown) to perform a four-step shift, and shifts the shift fork. In addition, the PTO speed change lever 86 is disposed on the right side of the driver seat 9 so as to be swingable up and down.

[Mission case]
The traveling system transmission mechanism and the PTO system transmission mechanism are disposed in the clutch housing 2 and the transmission case 3 in the state of being partitioned as follows.
That is, as shown in FIGS. 3 and 4, the clutch housing 2 and the transmission case 3 have a first chamber M1, a second chamber M2, a third chamber M3, a fourth chamber M4, and a fifth chamber M5 from the front side of the machine body. , Partitioned into a sixth chamber M6.
The main clutch 10 and the input shaft 11 are disposed in the first chamber M1, the main gear transmission mechanism 20 and the PTO clutch 70 are disposed in the second chamber M2, and the shift operation clutch 25 is disposed in the third chamber M3. A forward / reverse transmission mechanism 30 and a PTO transmission mechanism 80 are disposed in the fourth chamber M4, and a sub-gear transmission mechanism 40, a creep transmission mechanism 50, and a front wheel drive mechanism 60 are disposed in the fifth chamber M5. A differential mechanism 55 is disposed in the sixth chamber M6.

Each of the chambers M1 to M6 is partitioned by a first partition wall W1 to a sixth partition wall W6, and each shaft of the traveling system transmission mechanism and the PTO system transmission mechanism has a ball bearing or a thrust bearing on each partition wall W1 to W6. It is supported so that it can rotate freely.
In other words, the rear end side of the input shaft 11 is pivotally supported by the first partition wall W1, and the shafts on the front end side of the main gear speed change mechanism 20 and the PTO clutch 70 are supported by the first partition wall W1. Also, the front side is a first chamber M <b> 1 that is inside the clutch housing 2.
The second partition wall W2 supports the shafts on the rear end side of the main gear transmission mechanism 20 and the PTO clutch 70, the travel counter shaft 22 that supports the front end side of the clutch 25 for speed change operation, and the PTO speed change. A PTO speed change input shaft 81 for transmitting power to the mechanism 80 is supported, and a space between the second partition wall W2 and the first partition wall W1 is a second chamber M2 in the transmission case 3.

  The third partition wall W3 includes a shuttle main shaft 31 that supports the rear end side of the speed change operation clutch 25, other shafts on the front end side of the other forward / reverse transmission mechanism 30, and each shaft on the front end side of the PTO transmission mechanism 80. Is supported, and a space between the third partition wall W3 and the second partition wall W2 is a third chamber M3 in the mission case 3.

The fourth partition wall W4 supports the shafts on the rear end side of the forward / reverse transmission mechanism 30 and the shafts on the rear end side of the PTO transmission mechanism 80. The fifth partition wall W5 supports the shafts on the front end side of the auxiliary gear transmission mechanism 40 and the shafts on the front end side of the front wheel drive mechanism 60.
A space between the fourth partition wall W4 and the third partition wall W3 and between the fifth partition wall W5 and the fourth partition wall W4 is a fourth chamber M4 in the mission case 3.

  The sixth partition wall W6 supports the rear end shafts of the auxiliary gear transmission mechanism 40 and the rear end shafts of the front wheel drive mechanism 60. The sixth partition wall W6 and the fifth partition wall W5 are connected to each other. The space is the fifth chamber M5 in the mission case 3, and the rear side of the sixth partition wall W6 is the sixth chamber M6 in the mission case 3.

[Axis arrangement]
The arrangement of the shafts arranged in the chambers M1 to M6 is shown in FIGS.
FIG. 5 shows a cross section taken along line VV shown in FIG. 4 and shows a state in which the clutch housing 2 is cut in a vertical direction. Reference numeral 64 in the drawing denotes a front wheel drive shaft that extends forward from the four-wheel drive shaft 62 of the front wheel drive mechanism 60.
FIG. 6 shows a section taken along line VI-VI shown in FIG. 4 and shows a state in which the transmission case 3 is cut in the vertical direction. Reference numeral 16 in the figure covers the input part of the travel drive system. It is a cover body.

  FIG. 7 shows a section taken along line VII-VII shown in FIG. 4 and shows a state in which the transmission case 3 is cut in the vertical direction. The input shaft 11 and the traveling main shaft 21 and the PTO main shaft 71 are left and right. The travel counter shaft 22 is disposed below the travel main shaft 21, and the PTO counter shaft 72 is disposed below the PTO main shaft 71. In this state, the outer shape of the mission case 3 is a substantially horizontally long shape.

FIG. 8 shows a cross section taken along line VIII-VIII shown in FIG. 4 and shows a state in which the mission case 3 is cut in a vertical direction.
At this position, since the input shaft 11 does not exist, there is no projecting portion on the upper side of the mission case 3 for interior of the input shaft 11 portion, and the outer shape of the mission case 3 is further horizontally long. The outer shape of the mission case 3 is an outer shape in a range corresponding to a space between the fourth partition W4 and the third partition W3 in the third chamber M3 and the fourth chamber M4 in the mission case 3, and is substantially flat. The control unit deck 8 is disposed in a range including the upper portion of the outer shape of the transmission case 3. In addition, the code | symbol P in a figure shows the axial center position of the input shaft 11. FIG.

FIG. 9 shows a cross section taken along the line IX-IX shown in FIG. 4, and shows a state in which the mission case 3 is cut in a vertical direction.
In this position, the position corresponds to the lower side of the driver's seat 9 in the front-rear direction, and the vertical dimension of the transmission case 3 increases in FIG. 10 to be described later, so that the case cross section is gradually increased in the vertical direction. The shape has a protruding portion.

FIG. 10 shows a cross section taken along line XX shown in FIG. 4 and shows a state in which the mission case 3 is cut in a vertical direction.
In this position, the position corresponds to the lower side of the driver seat 9 in the front-rear direction, and many transmission mechanisms such as the auxiliary gear transmission mechanism 40, the creep transmission mechanism 50, and the front wheel drive mechanism 60 are complicated. The dimensions are increased, and the outer shape of the mission case 3 is nearly vertically long.

FIG. 11 shows the positional relationship between the shafts disposed in the clutch housing 2 and the transmission case 3 in one drawing when viewed in the front-rear direction from the rear side.
As shown in this figure, the traveling main shaft 21 and the PTO main shaft 71 are distributed to the left and right from the input shaft 11 and are disposed obliquely below, and the traveling counter shaft 22 is disposed obliquely below the traveling main shaft 21 and is coaxial. A shift operation clutch 25 is disposed above. In addition, a PTO counter shaft 72 is disposed at an obliquely outward position below the PTO main shaft 71, and a PTO clutch 70 is disposed on the coaxial core.

In the travel drive system, a shuttle main shaft 31 of the forward / reverse transmission mechanism 30 is disposed coaxially with the travel counter shaft 22, and the oblique outer side and the oblique inner side on the upper side within the transmission case 3 from the position of the shuttle main shaft 31. The shuttle counter shaft 32 and the shuttle back shaft 33 are arranged separately.
An auxiliary transmission input shaft 41 of the auxiliary gear transmission mechanism 40 is disposed on the same axis as the shuttle counter shaft 32, and a bevel pinion gear shaft 42 is disposed further obliquely inward from the shuttle counter shaft 32. The bevel pinion gear shaft 42 is disposed at a position close to the center position in the lateral direction of the self-propelled vehicle body and close to an extension line of the input shaft 11.
The creep transmission shaft 51 of the creep transmission mechanism 50 is disposed at an obliquely outward position above the bevel pinion gear shaft 42 and above the position where a PTO transmission mechanism 80 described later is disposed. Yes, the double speed drive shaft 61 and the four wheel drive shaft 62 of the front wheel drive mechanism 60 are disposed on the lower side lower than the place where the PTO transmission mechanism 80 is disposed.

In the PTO drive system, a PTO speed change input shaft 81 of the PTO speed change mechanism 80 is disposed on the upper side of the PTO countershaft 72 and obliquely inward. The PTO speed change input shaft 81 is disposed so as to be positioned coaxially with the PTO main shaft 71.
Further, a PTO shift counter shaft 82 is disposed at an obliquely outward position below the PTO shift input shaft 81, and is higher than the axis of the PTO shift input shaft 81 at an outward position of the PTO shift input shaft 81. A PTO transmission reverse rotation shaft 83 is disposed at the position. The arrangement position of the PTO speed change counter shaft 82 is substantially coaxial with the PTO counter shaft 72 in the height and lateral direction.
A PTO shaft 15 is disposed on the upper side of the PTO speed change counter shaft 82 and at an obliquely inward position. The PTO shaft 15 is disposed at a position close to the center position in the lateral direction of the self-running vehicle body and at a position vertically below the input shaft 11.

  The imaginary line showing the outer shape of the clutch housing 2 shown in FIG. 11 represents the outer shape of the cross section at the position shown in FIG. 6, and the two imaginary lines representing the outer shape of the mission case 3 are at the position shown in FIG. The external shape of a cross section and the external shape of the cross section in the position shown in FIG. 10 are represented.

[Other Embodiments]
In the above embodiment, the PTO main shaft 71 in the PTO drive system and the PTO speed change input shaft 81 of the PTO speed change mechanism 80 are arranged on the same axis as the PTO main shaft 71. The shaft core of the PTO main shaft 71 and the shaft core of the PTO speed change input shaft 81 of the PTO speed change mechanism 80 may be disposed so as to be displaced from each other.

  As shown in the embodiment, the present invention is not limited to a structure in which each operation of the traveling drive system and the PTO drive system is performed by hydraulic operation means, but a structure in which the operation is performed manually by using a mechanical operation mechanism. It can also be applied to those.

DESCRIPTION OF SYMBOLS 1 Engine 3 Mission case 10 Main clutch 11 Input shaft 12 Traveling system input shaft 12a Traveling system output gear 13 PTO system input shaft 13a PTO system output gear 15 PTO shaft 20 Gear transmission mechanism (main gear transmission mechanism)
21 traveling spindle 21a traveling input gear 22 traveling counter shaft
5 5 traveling def Organization
7 0 PTO clutch 71 PTO main shaft 71a PTO input gear 72 PTO counter shaft 80 PTO speed change mechanism 81 PTO speed change input shaft 82 PTO speed change counter shaft 83 PTO speed change reverse shaft

Claims (2)

The power of the input shaft to which the engine power is transmitted is branched into the traveling drive system and the PTO drive system in the transmission case, and the power of the traveling drive system is transmitted to the traveling differential mechanism, and the power of the PTO drive system is also transmitted to the PTO shaft. In the tractor configured to be taken out of the mission case from
The input shaft is connected to a traveling system input shaft configured such that a driving force is interrupted by an on / off operation of a main clutch disposed on the upper side in the transmission direction, and an engine side regardless of an on / off operation of the main clutch. A PTO system input shaft configured to transmit power is composed of an inner / outer double shaft concentrically provided,
A traveling main shaft that is provided with a traveling input gear that meshes with a traveling system output gear provided on the traveling system input shaft and that transmits a driving force; and a PTO input gear that meshes with a PTO output gear provided on the PTO input shaft. And a PTO main shaft to which a driving force is transmitted, and is distributed and arranged at both lateral positions across the axis of the input shaft,
With arranging the traveling counter shaft to which power is transmitted from the driving spindle to the lower side of the traveling spindle, constitutes a gear transmission mechanism comprises a speed change gear and the traveling spindle and the travel counter shaft,
A PTO counter shaft that transmits power on the PTO main shaft side is disposed below and laterally outside the PTO main shaft, and a PTO clutch that interrupts the power to the PTO drive system is connected to the PTO counter shaft from the PTO main shaft. While preparing to be located on the rear side ,
Wherein comprising a PTO transmission input shaft for transmitting power to the PTO speed change mechanism on the upper side than the PTO counter shaft, the power input via said PTO clutch to the PTO speed change input shaft, said by shifting in the PTO transmission mechanism A tractor characterized by being configured to be removed from the PTO shaft. In the PTO transmission mechanism, a PTO transmission counter shaft to which the power is transmitted from the PTO speed change input shaft, and a PTO transmission reverse shaft, wherein by reversing the power transmitted from the PTO transmission input shaft is transmitted to the PTO speed change counter shaft and on one side of the lateral side of the PTO speed change input shaft, the tractor according to claim 1, wherein are disposed by distributing vertically.

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