JP2004114909A - Pto driving device for tractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten distance in the forward and backward directions from a rear axle 61 to a rear PTO shaft 25 in a transmission case 13 of a tractor to improve balance and work stability of a vehicle body when mounting a work machine. <P>SOLUTION: A rear axle differential gear 60 and a PTO driving device are arranged in a rear part of the transmission case 13. A part of the PTO driving device 21 is arranged in a scope of projection of a ring gear 63 constituting the rear axle differential gear 60 when viewed on a side. The PTO driving device 21 is provided on a tooth flank side of the ring gear 63. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tractor PTO drive device, and more particularly to a technique for shortening a front-rear distance between a rear wheel differential and a rear PTO shaft to make a transmission case compact.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a tractor that allows a work machine to be mounted behind a vehicle body and that performs various operations by pulling and driving the work machine has been known.
In a transmission case of this tractor, a structure in which a PTO drive device is arranged behind a rear wheel differential device is already known, and power is transmitted to a work machine by the PTO drive device.
In such a configuration in which a PTO drive device is disposed behind such a rear wheel differential device, complicated devices such as a reduction gear and a PTO transmission are used to transmit power to a rear PTO shaft. And the front-rear distance between the differential device in the transmission case and the rear PTO shaft that transmits power to the work equipment was likely to be long, and the front-rear balance of the vehicle body when the work equipment was mounted was poor. . For this reason, there is known a technology for providing a PTO drive device as disclosed in Patent Document 1 compactly at the rear of a rear axle differential device to shorten the longitudinal distance between the differential device and the rear PTO shaft. .
[0003]
FIG. 6 is a side sectional view showing the configuration of a conventional transmission case, and arrow A is in front of the transmission case.
For example, as shown in FIG. 6, in a conventional transmission case 113, a ring gear 163 of a rear wheel (rear axle) differential device is disposed at a rear portion in a side view, and a PTO drive device (a reduction gear and a PTO clutch) is disposed behind the gear 163. ) 121 was provided. The ring gear 163 is formed of a bevel gear, and its tooth surface is arranged on one side of the left and right sides. The input shaft of the rear PTO shaft 25 ′ is located on the tooth surface side of the ring gear 163 in the side projection range. Although arranged, the transmission that transmits power by shifting the power from the input shaft to the rear PTO shaft is disposed further behind the projection range of the ring gear.
[0004]
[Patent Document 1]
JP-A-5-50866
[Problems to be solved by the invention]
However, in the conventional structure as described above, the projection range of the ring gear and the PTO drive device are arranged in the transmission case with a distance that does not make contact with the PTO drive device in a side view. And since it is such a structure, the distance in the front-rear direction from the rear axle to the rear PTO shaft becomes long, and it is necessary to secure a space for installing a joint shaft between the rear PTO shaft and the input shaft. As a result, the distance from the work machine mounting position became large, and the front-rear balance and work stability of the vehicle body when the work machine was mounted were deteriorated.
In view of the above problems, the present invention aims to improve work stability by mounting a working machine as forward as possible.
[0006]
[Means for Solving the Problems]
The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.
[0007]
That is, in claim 1, a rear axle differential device and a PTO drive device are arranged in a rear portion of a transmission case, and a ring gear projection that constitutes the rear axle differential device when a part of the PTO drive device is viewed from a side. It is arranged within the range.
[0008]
According to a second aspect of the present invention, the PTO driving device is provided on a tooth surface side of a ring gear.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the invention will be described.
1 is a side view showing the entire configuration of the tractor, FIG. 2 is a side sectional view of the transmission case, FIG. 3 is an enlarged sectional view of the transmission case showing the configuration of the rear half of the PTO first transmission shaft, and FIG. FIG. 5 is a plan view of the rear cross section.
[0010]
First, a schematic configuration of a tractor including the PTO drive device 21 according to the present invention will be described.
In FIG. 1, an engine 2 is disposed on a front portion of a body frame 1, the engine 2 is covered with a bonnet 3, and a handle 5 serving as a steering means is projected on a dashboard 4 at a rear portion of the bonnet 3. . A seat 6 is disposed behind the handle 5, and a main shift lever, an auxiliary shift lever, a PTO shift lever, and the like are disposed on a side portion of the seat 6, and the seat 6, the main shift lever, the handle 5, etc. The portion where is disposed is a control unit 9.
[0011]
A transmission case 13 is connected to a rear portion of the body frame 1, and a rear wheel 15 is supported on both sides of the transmission case 13 via a rear axle case 12. A hydrostatic continuously variable transmission (HST) is provided at the front of the transmission case 13 so that the output of the engine can be transmitted to the input shaft 51 of the HST via a transmission shaft. In the transmission case 13, a sub-transmission, a differential, and the like for driving a rear axle 61 that is mounted on the left and right are disposed, and a PTO driving device is disposed behind the differential. Power can be transmitted to the rear PTO shaft 25. At the rear of the transmission case 13, there is provided a three-point link type working equipment mounting device 16 for mounting various working machines, and a rear PTO shaft 25 protruding from the rear surface of the transmission case 13 is used to perform work. Machine can be driven. Further, a front wheel drive take-out shaft and a front PTO shaft 27 protrude forward from a lower front portion of the transmission case 13, and transmit power from the front wheel drive take-out shaft to a front axle case 20 via a transmission shaft 19, and are supported by the front axle case 20. The front wheel 14 can be driven.
[0012]
Next, the internal configuration of the mission case 13 according to the present invention will be described.
First, as shown in FIG. 2, a hydrostatic continuously variable transmission (HST) 50 as a main transmission mechanism is attached to a front end portion of the transmission case 13 and is covered with a transmission case 10, and its input shaft 51 is moved forward. Protruding. A front portion of the input shaft 51 is connected to an output shaft of the engine via a transmission shaft and a damper. The input shaft 51 extends rearward through the inside of the HST case 56, and a rear end of the input shaft 51 is The front end of the PTO first transmission shaft 22, which is the PTO transmission shaft, and the axis of the input shaft 51 are arranged so as to coincide with each other.
[0013]
The hydrostatic continuously variable transmission 50 has a variable displacement hydraulic pump and a fixed displacement hydraulic motor housed in an HST case 56, and the hydraulic pump is driven by the input shaft 51 and is interlocked with a main shift lever. When the trunnion shaft is connected to the movable swash plate and the main transmission lever is rotated to change the speed, the tilt angle of the movable swash plate is changed, and the discharge direction and discharge amount of hydraulic oil from the hydraulic pump are changed. The rotation direction and the number of rotations of the output shaft 52 of the motor are configured to be changed. The output shaft 52 projects rearward from the lower rear surface of the HST case 56, and an output gear 53 is fixed to the rear end of the output shaft 52. The output gear 53 meshes with a transmission gear 55 loosely fitted to a traveling output shaft 54 disposed below the drive shaft 52, and is driven by the traveling output shaft 54 from the transmission gear 55 via an auxiliary transmission (not shown). Power is transmitted to the traveling output gear 57 fixed above. The bevel gear 54a formed at the rear end of the traveling output shaft 54 is meshed with the ring gear 63 (FIG. 4) of the rear axle differential device 60, and the power is input to the bevel gear 54a. The rear axle 61 on which the shaft is mounted can be driven.
[0014]
Further, a PTO clutch device 33 including a friction clutch and the like is disposed between the rear end of the input shaft 51 and the front end of the PTO first transmission shaft 22. The PTO clutch device 33 includes a boss body 35, a clutch case 58, a friction plate alternately arranged between the boss body 35 and the clutch case 58, and presses the friction plate. A pressing member 59, a sliding member 62 on the pressing member 59 via a bolt or the like, a contact member 66 loosely fitted on the PTO first transmission shaft 22 via a bearing on the sliding member 62, and a corresponding contact member 66. It is composed of a pushing cam body 34 and the like.
[0015]
The PTO clutch device 33 is disposed in an upper space of a space formed at a front portion of a wall portion 13 a formed at a front and rear central portion of the transmission case 13, and the cam body 34 is provided with a PTO clutch operating tool provided at the control section 9. The contact member 66 is slid forward on the PTO first transmission shaft 22 by the rotation of the cam body 34, and presses the friction plate via the sliding member 62, the bolt, and the pressing member 59. Thus, the boss 35 and the clutch case 58 fixed on the PTO first transmission shaft 22 are integrally rotated. That is, the power from the engine is transmitted to the PTO shaft 25 by setting the PTO clutch device 33 to “contact” by operating the PTO clutch operation tool.
[0016]
A rear portion of the PTO first transmission shaft 22 is supported by bearings on a rear wall portion 31 of the transmission case, and a mid-PTO shaft drive gear 44 is loosely fitted on the rear portion of the PTO first transmission shaft 22 via a needle bearing 36, A spline is formed on the PTO first transmission shaft 22 at the rear portion, and the switching slider 41 is spline-fitted. The switching slider 41 is formed with internal teeth so that the switching slider 41 can mesh with the mid-PTO shaft drive gear 44.
[0017]
The front portion of the rear PTO drive shaft 42 is fitted on the rear end of the PTO first transmission shaft 22 coaxially via a needle bearing 37 so as to be relatively rotatable, and a spline is provided on the outer periphery of the front portion of the PTO first transmission shaft 22. It is formed so as to be spline-fittable with the switching slider 41, and the rear part of the rear PTO drive shaft 42 is rotatably supported by the wall part 30 at the rear part of the transmission case 13 via a bearing.
Further, a tooth portion 42 a is formed on the rear PTO drive shaft 42, and meshes with a gear 45 fixed on a front portion of the rear PTO shaft 25, so that power can be transmitted to the rear PTO shaft 25. .
[0018]
A second transmission shaft 23 is supported by the walls 30 and 31 below the PTO first transmission shaft 22 so as to be rotatable in parallel via bearings. A wall portion 32 is provided below and behind the wall portion 31, and a third transmission shaft 24 and a fourth transmission shaft 26 are arranged in parallel below the second transmission shaft 23 between the wall portion 32 and the wall portion 30. It is rotatably supported. A mid-PTO shaft 27 is supported below the transmission shafts 22, 23, 24 and 26 between the wall portion 30 and the wall portion 13a in a rotatable and parallel manner.
[0019]
The mid-PTO shaft drive gear 44 always meshes with a gear 43 fixed to the second transmission shaft 23 disposed below the PTO first transmission shaft 22, and is disposed below the gear 43 second transmission shaft 23. With the gear 46 fixed on the third transmission shaft 24. A gear 47 is fixed on the third transmission shaft 24 at the rear of the gear 46, and the gear 47 is always meshed with a gear 48 fixed on the fourth transmission shaft 26. The gear 48 on the fourth transmission shaft 26 meshes with a gear 49 fixed to a rear portion of the mid PTO shaft 27 disposed below the fourth transmission shaft 26. With such a configuration, the power transmitted from the mid-PTO shaft drive gear 44 can be transmitted to the mid-PTO shaft 19.
[0020]
In such a configuration, by operating the PTO switching lever connected to the switching slider 41 and sliding the switching slider 41 in the axial direction, the switching slider 41, the rear PTO drive shaft 42, and the PTO first transmission shaft 22 When the switching slider 41 is positioned at a position where the three members are spline-fitted, that is, when the switching slider 41 is switched to the rear PTO driving position, the switching slider 41, the rear PTO driving shaft 42, and the gear 45 are transmitted from the PTO first transmission shaft 22. Thus, the rear PTO shaft 25 can be rotationally driven.
[0021]
When the internal teeth 41a of the switching slider 41 are engaged with the mid-PTO driving gear 44 and are not splined with the rear PTO driving shaft 42, that is, when the switching to the mid-PTO driving position is performed, the PTO first transmission is performed. The transmission is transmitted from the shaft 22 to the mid-PTO shaft 27 via the switching slider 41, the mid-PTO drive gear 44, the gear 43, the gear 46, the third transmission shaft 24, the gear 47, the gear 48, and the gear 49, and from the mid-PTO shaft 27 Power is transmitted to the mid-mount machine.
Also, when the switching slider 41 is spline-fitted between the rear PTO drive shaft 42 and the PTO first transmission shaft 22 and slides to a position where it meshes with the mid PTO drive gear 44, that is, the rear PTO / mid PTO drive position Upon switching, power is transmitted to both the rear PTO shaft 25 and the mid PTO shaft 27 in the same manner as described above. Reference numeral 67 in FIG. 5 denotes a switching shaft connected to the PTO switching lever.
[0022]
Next, the arrangement of the PTO drive device 21 and the rear axle differential device 60 according to the present invention will be described in more detail with reference to FIGS.
The PTO drive device 21 includes a switching mechanism 21a and a reduction gear mechanism 21b, and is disposed at the rear of the transmission case 13. The PTO first transmission shaft 22 is positioned above the rear axle differential device 60 in the front-rear direction, and a switching mechanism 21 a is provided at a position above and behind the rear axle differential device 60.
[0023]
The reduction gear mechanism 21b (PTO drive device 21) is arranged so that a part thereof overlaps the rear axle differential device 60 in a side view. In other words, the reduction gear of the rear PTO shaft drive system is located behind the wall 30 at the rear end of the transmission case 13 and is covered by the gear case 71, does not overlap with the rear axle differential device 60 in side view, and The gears 43 and 46 of the reduction gear of the drive system are arranged so as to overlap in side view. That is, since the ring gear 63 of the rear axle differential device 60 is formed of a bevel gear, when the bevel gear 54a of the traveling output shaft 54 is disposed substantially at the center of the transmission case 13 on the left and right, the ring gear 63 is on the left and right sides. (Tooth surface side 63a, in this embodiment, eccentrically disposed in the traveling direction), a space (dead space) 65 is generated on the other side (left side) in the transmission case 13. In the present invention, the transmission mechanism of the mid-PTO drive system is arranged in this space 65, but partially overlaps in a side view, but does not overlap in a plan view and a rear view. Therefore, the length of the transmission case 13 in the front-rear direction is being reduced.
[0024]
Further, in order to configure a part of the reduction gear mechanism 21b so as to overlap the rear axle differential device 60 in a side view, the second transmission shaft 23, the third transmission shaft 24, the fourth transmission shaft 26, As shown in FIG. 4, the PTO shafts 27 are arranged substantially vertically in a row, and as shown in FIG. 2, the second transmission shaft 23, the third transmission shaft 24, and the fourth transmission shaft 26 are stepwise viewed from the side. The rear axle differential 60 is arranged such that the front portion of each axis faces the projection range of the rear axle differential device 60. In this manner, the ring gear 63 is arranged so as to overlap as much as possible in the vicinity of the outer periphery thereof so as not to interfere with a differential side key, a differential pinion, and the like disposed in the center of the ring gear 63. Further, a wall portion 31 that supports the front portion of the second transmission shaft 23 and a wall portion 32 that supports the front portions of the third transmission shaft 24 and the fourth transmission shaft 26 are each a rear axle differential device in side view. It is arranged stepwise so as to overlap with 60.
[0025]
An opening 69 slightly larger than the outer diameter of the ring gear 63 is provided on the side opposite to the tooth surface of the transmission case, and the opening 69 is closed by a removable lid 70. By removing the lid 70, the rear axle differential device 60 housed in the transmission case 13 can be detached.
[0026]
By arranging the shaft constituting the PTO drive device 21 and the gear fixed to the shaft so as to face the projection range of the ring gear 63 when viewed from the side, the shaft is provided at the center of the rear axle differential. The front-rear distance between the rear axle and the rear PTO shaft 25 can be shortened, and the front-rear balance of the tractor body when the work machine is mounted is improved, so that work stability can be improved. Further, the size and weight of the transmission case can be reduced.
[0027]
【The invention's effect】
The present invention is configured as described above, and has the following effects.
[0028]
That is, as shown in claim 1, a rear axle differential device and a PTO drive device are arranged in the rear portion of the transmission case, and a ring gear that constitutes the rear axle differential device when a part of the PTO drive device is viewed from the side. Since it is located within the projection range, the distance between the rear PTO axis and the center of the rear axle can be shortened. Further, the front-rear balance of the tractor vehicle is improved, and work stability is improved. Further, the size and weight of the transmission case can be reduced.
[0029]
Since the PTO drive device is provided on the tooth surface side of the ring gear, the PTO drive device can be compactly stored in the transmission case, and the distance between the rear PTO shaft and the center of the rear axle can be shortened. And work stability is improved.
[Brief description of the drawings]
FIG. 1 is a side view showing the overall configuration of a tractor.
FIG. 2 is a side sectional view of a transmission case.
FIG. 3 is an enlarged cross-sectional view of a transmission case showing a configuration of a rear half of a PTO first transmission shaft.
FIG. 4 is a rear sectional view of the transmission case.
FIG. 5 is a plan view of the same.
FIG. 6 is a side sectional view showing a configuration of a conventional transmission case.
[Explanation of symbols]
13 Transmission case 21 PTO drive device 22 PTO first transmission shaft 23 Second transmission shaft 24 Third transmission shaft 25 Rear PTO shaft 26 Fourth transmission shaft 27 Mid PTO shaft 60 Rear axle differential device 61 Rear axle 63 Ring gear 63a Tooth Surface side

Claims (2)

A rear axle differential device and a PTO drive device are arranged in the rear of the transmission case, and a part of the PTO drive device is disposed in a projection area of a ring gear constituting the rear axle differential device in side view. PTO drive device for a tractor. The PTO drive device for a tractor according to claim 1, wherein the PTO drive device is provided on a tooth surface side of a ring gear.

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