JP2012101614A - Power transmission structure for working vehicle - Google Patents

Power transmission structure for working vehicle Download PDF

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Publication number
JP2012101614A
JP2012101614A JP2010250358A JP2010250358A JP2012101614A JP 2012101614 A JP2012101614 A JP 2012101614A JP 2010250358 A JP2010250358 A JP 2010250358A JP 2010250358 A JP2010250358 A JP 2010250358A JP 2012101614 A JP2012101614 A JP 2012101614A
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Japan
Prior art keywords
pto
transmission
shaft
clutch
case
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Pending
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JP2010250358A
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Japanese (ja)
Inventor
Masahiro Hanabusa
Masao Hirai
Terunobu Yoshioka
輝延 吉岡
正雄 平井
昌弘 花房
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Yanmar Co Ltd
ヤンマー株式会社
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Application filed by Yanmar Co Ltd, ヤンマー株式会社 filed Critical Yanmar Co Ltd
Priority to JP2010250358A priority Critical patent/JP2012101614A/en
Publication of JP2012101614A publication Critical patent/JP2012101614A/en
Pending legal-status Critical Current

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Abstract

An object of the present invention is to provide a power transmission structure for a work vehicle that can reduce the number of parts.
A power transmission structure for a tractor 1 serving as a work vehicle in which a PTO transmission portion 8B is formed at a rear portion of a transmission case 8, and a rear PTO shaft 230 and a mid PTO shaft 240 are supported by the PTO transmission portion 8B. Power is transmitted from the PTO input shaft 220 to the rear PTO shaft 230 via the speed reduction mechanism 270, and power can be transmitted from the rear PTO shaft 230 to the mid PTO shaft 240 via the mid PTO clutch 290. Is.
[Selection] Figure 4

Description

  The present invention relates to a power transmission structure for a work vehicle.

2. Description of the Related Art Conventionally, a power transmission structure for a work vehicle including a rear PTO shaft and a mid PTO shaft has been known (see, for example, Patent Document 1).
The work vehicle power transmission structure disclosed in Patent Document 1 is configured such that engine power is transmitted from the PTO transmission shaft (PTO input shaft) to the mid PTO shaft via the mid PTO transmission gear train. The PTO transmission shaft (PTO input shaft) is transmitted to the rear PTO shaft via the rear PTO transmission gear train.

JP 2007-112439 A

  However, in the power transmission structure for a work vehicle shown in Patent Document 1, a reduction mechanism (mid PTO transmission gear train and rear PTO transmission gear train) is provided for each of the mid PTO shaft and the rear PTO shaft. There was a problem of increasing.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a power transmission structure for a work vehicle that can reduce the number of parts.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  In claim 1, a power transmission structure for a work vehicle in which a PTO transmission portion is formed at a rear portion of a transmission case, and a rear PTO shaft and a mid PTO shaft are supported on the PTO transmission portion. The power is transmitted to the rear PTO shaft via the rear PTO shaft, and the power can be transmitted from the rear PTO shaft to the mid PTO via the mid PTO clutch.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect of the present invention, it is possible to reduce the number of parts by combining the speed reduction mechanism for reducing the power of the rear PTO shaft with the speed reduction mechanism for reducing the power of the mid.

1 is an overall side view of a work vehicle according to an embodiment of the present invention. The figure which shows the whole structure of a transmission. The figure which shows the whole structure of a clutch mechanism and a PTO brake. (A) The traveling clutch is “off”, the PTO clutch is “off”, and the PTO brake is “on”. (B) The traveling clutch is “ON”, the PTO clutch is “ON”, and the PTO brake is “OFF”. The figure which shows the power transmission structure of a PTO transmission part.

  First, an embodiment of a work vehicle according to the present invention is referred to as a tractor 1, and the overall configuration of the tractor 1 will be described with reference to FIG. Note that the direction of the arrow F shown in FIG.

  In the tractor 1, the body frame 2 is arranged with the longitudinal direction as the front-rear direction, and is supported by a pair of left and right front wheels 3 and 3 via a front axle at the front portion and a pair of left and right via a rear axle at the rear portion. Supported by the rear wheels 4. An engine 6 covered with a bonnet 5 is provided at the front of the body frame 2, a driving operation unit 9 is provided behind the bonnet 5, and a transmission 7 described later (see FIG. 2) at the rear of the body frame 2. ) Is provided.

  Below, the transmission 7 which is a transmission of a work vehicle is demonstrated using FIG.

  The transmission 7 outputs power after shifting the power from the engine 6 (see FIG. 1) as a drive source. The transmission 7 includes a mission input shaft 20, a clutch mechanism 200, a belt-type continuously variable transmission 40 serving as a traveling transmission, an output shaft 170, a front wheel drive transmission shaft 180, a PTO brake 210, a PTO input shaft 220, a rear PTO shaft 230, And a mid PTO shaft 240 and the like, and housed in the mission case 8.

The power from the engine 6 is transmitted to the mission input shaft 20 and then transmitted to the belt type continuously variable transmission 40 and the PTO input shaft 220 via the clutch mechanism 200.
The power transmitted to the belt-type continuously variable transmission 40 is continuously shifted in the belt-type continuously variable transmission 40 and then transmitted to the output shaft 170 and the front wheel drive transmission shaft 180.
The power transmitted to the output shaft 170 is transmitted to the rear wheels 4 and 4 of the tractor 1 through a final reduction mechanism (not shown) or the like.
The power transmitted to the front wheel drive transmission shaft 180 is transmitted to the front wheels 3 and 3 of the tractor 1 through a front axle (not shown) and the like.
The power transmitted to the PTO input shaft 220 is transmitted to the rear PTO shaft 230 and the mid PTO shaft 240 via gears and the like.

In the transmission 7 configured as described above, the vehicle speed of the tractor 1 can be arbitrarily adjusted by changing the gear ratio in the belt-type continuously variable transmission 40.
In addition, a working machine (for example, a rotary tiller or the like) coupled to the rear PTO shaft 230 by a power transmitted to the rear PTO shaft 230 and the mid PTO shaft 240, and a working machine coupled to the mid PTO shaft 240, In the present embodiment, the midmore 10 (see FIG. 1) can be driven.
Further, when the transmission of power from the engine 6 to the PTO input shaft 220 is interrupted by the clutch mechanism 200, the rotation of the PTO input shaft 220 is braked by the PTO brake 210.

  Below, each part of belt type continuously variable transmission 40 is explained. The belt type continuously variable transmission 40 includes a transmission input shaft 50, an input pulley 60, a hydraulic cylinder 70, a hydraulic servo mechanism 80, a transmission shaft 90, an output pulley 100, an output member 110, a cam mechanism 120, a biasing member 130, and a belt 140. And a planetary gear mechanism 150 and the like.

A transmission input shaft 50 shown in FIG. 2 is connected to the mission input shaft 20 and transmits power from the mission input shaft 20. The transmission input shaft 50 is a substantially cylindrical member, and is arranged with the axial direction as the front-rear direction.
An enlarged diameter portion 50a having a larger diameter than that of the other portion is formed in the middle portion before and after the transmission input shaft 50.
In the vicinity of the rear end portion of the transmission input shaft 50, the transmission input gear 51 is connected to the transmission input shaft 50 so as not to rotate relative thereto by spline fitting. The transmission input gear 51 is meshed with the gear of the clutch mechanism 200, and the power of the mission input shaft 20 can be transmitted through the clutch mechanism 200. The method of connecting the transmission input gear 51 to the transmission input shaft 50 is not limited to the spline fitting, and the transmission input gear 51 can be formed integrally with the transmission input shaft 50 or the like.
Immediately behind the speed change input gear 51, the bearing 52 is fitted to the speed change input shaft 50. Further, the bearing 53 is fitted to the transmission input shaft 50 in front of the enlarged diameter portion 50a. The transmission 52 is supported by the transmission case 8 in a rotatable manner by supporting the bearing 52 in the transmission case 8 that houses the transmission 7 and the bearing 53 in the front case 81.

  The input pulley 60 is a pulley that is disposed on the transmission input shaft 50 and includes a pair of sheaves. The input pulley 60 includes an input side fixed sheave 61, an input side movable sheave 63, and the like.

  The hydraulic cylinder 70 is for sliding the input side movable sheave 63 on the transmission input shaft 50 in the axial direction thereof. The hydraulic cylinder 70 includes a movable cylinder case 71, a fixed cylinder case 73, and the like.

  The hydraulic servo mechanism 80 is for controlling the operation of the input side movable sheave 63 via the hydraulic cylinder 70. The hydraulic servo mechanism 80 includes a front case 81, a servo spool 83, a feedback spool, a spool spring, and the like.

The transmission shaft 90 transmits power from the transmission input shaft 50. The transmission shaft 90 is a substantially cylindrical member, and is arranged with the axial direction as the front-rear direction.
In the vicinity of the front end portion of the transmission shaft 90, an enlarged diameter portion 90a having a larger diameter than other portions is formed.
A bearing 91 is fitted to the transmission shaft 90 in front of the enlarged diameter portion 90a. By supporting the bearing 91 on the transmission case 8, the transmission shaft 90 is rotatably supported on the transmission case 8.

  The output pulley 100 is a pulley that is disposed on the transmission shaft 90 and includes a pair of sheaves. The output pulley 100 includes an output side fixed sheave 101, an output side movable sheave 103, and the like.

  The output member 110 is for transmitting the power from the cam mechanism 120 to the planetary gear mechanism 150.

  The cam mechanism 120 enables torque transmission between the output pulley 100 and the output member 110. The cam mechanism 120 includes a first cam 121, a second cam 122, and the like.

  The urging member 130 urges the output side movable sheave 103 forward. By the urging force of the urging member 130, the output side movable sheave 103 is urged forward, that is, in a direction close to the output side fixed sheave 101.

  The belt 140 is wound around the groove of the input pulley 60 and the groove of the output pulley 100, and transmits the power of the input pulley 60 to the output pulley 100. The belt 140 is a metal belt including a band in which metal thin plates are stacked and a metal element. The present invention is not limited to this, and a belt made of rubber, a chain, or a resin may be used as the belt 140.

  The belt 140 wound around the groove of the input pulley 60 is clamped by the input pulley 60 when the input side movable sheave 63 is pushed toward the input side fixed sheave 61 by the hydraulic cylinder 70 with a predetermined force. The belt 140 wound around the groove of the output pulley 100 is pushed to the output pulley 100 by the output side movable sheave 103 being pushed toward the output side fixed sheave 101 side with a predetermined force by the urging force of the urging member 130. It is pinched.

  The planetary gear mechanism 150 is for combining and outputting two powers. The planetary gear mechanism includes a sun gear 151, a ring gear 152, a carrier gear 153, planetary shafts 155, 155, planetary gears 157, 157, and a planetary output member 163.

  Hereinafter, an outline of power transmission and speed change in the belt type continuously variable transmission 40 configured as described above will be described.

  When power from the engine is transmitted to the transmission input shaft 50 via the mission input shaft 20 and the clutch mechanism 200, the input pulley 60 is also rotated together with the transmission input shaft 50. When the input pulley 60 is rotated, the output pulley 100 is rotated via the belt 140. When the output pulley 100 is rotated, the first cam 121 fixed to the output pulley 100 is rotated. When the first cam 121 rotates, the rear surface (inclined surface) of the first cam 121 and the front surface (inclined surface) of the second cam 122 come into contact with each other. It is rotated. When the second cam 122 is rotated, the sun gear 151 of the planetary gear mechanism 150 is rotated via the output member 110. When the sun gear 151 is rotated, the planetary gears 157, 157... Meshed with the sun gear 151 rotate (rotate) around the planetary shafts 155, 155.

  On the other hand, the power from the engine is transmitted to the carrier gear 153 of the planetary gear mechanism 150 via the mission input shaft 20 and the clutch mechanism 200 (that is, not shifted by the input pulley 60, the output pulley 100, and the belt 140). Then, together with the carrier gear 153, planetary gears 157, 157... Supported by the carrier gear 153 rotate (revolve) around the transmission shaft 90.

  Thus, the power transmitted from the mission input shaft 20 to the planetary gear mechanism 150 via the belt 140 and the power transmitted from the mission input shaft 20 directly to the planetary gear mechanism 150 without passing through the belt 140 are the planets. Are combined by planetary gears 157, 157. The combined power is transmitted to the output shaft 170 via the ring gear 152 meshed with the planetary gears 157, 157... And the planetary output member 163.

  Below, the structure of the clutch mechanism 200 and the PTO brake 210 is demonstrated in detail using FIG.2 and FIG.3.

  The clutch mechanism 200 transmits or blocks the power of the engine 6 transmitted to the mission input shaft 20 to each of the traveling system power transmission structure and the PTO system power transmission structure.

  As shown in FIG. 2, the mission input shaft 20 is arranged with the axial center direction as the front-rear direction, and the front and rear portions thereof are supported by the mission case 8 via bearings 21 and 22. One end 20a (front side) of the mission input shaft 20 protrudes forward from the mission case 8 to transmit power from the engine 6. The other end 20b (rear side) of the mission input shaft 20 is disposed at the approximate center in the front-rear direction of the mission case 8, and the clutch mechanism 200 and the PTO brake 210 are integrally disposed on the other end 20b side.

  The mission case 8 includes a front case 8a, a middle case 8b, and a rear case 8c, and is configured to be divided into three parts in the front-rear direction. The clutch mechanism 200 and the PTO brake 210 are housed in the front upper part of the middle case 8b, and the belt-type continuously variable transmission 40 is housed in the lower part from the upper and lower central parts of the front case 8a. A PTO transmission unit 8B is disposed between them. The transmission case 8 is configured to be divided into the front case 8a, the middle case 8b, and the rear case 8c so that assembly and maintenance can be easily performed.

  As shown in FIGS. 3A and 3B, the mission input shaft 20 is formed with a first hydraulic oil passage 20c and a second hydraulic oil passage 20d in parallel with the axis. One end (front end) of the first hydraulic fluid passage 20c and the second hydraulic fluid passage 20d is connected to a hydraulic valve from the front of the mission input shaft 20, and the other end (rear end) of the first hydraulic fluid passage 20c is traveling. A second oil chamber 200b and a PTO, which will be described later, are connected to a first oil chamber 200a, which will be described later, for operating the clutch 250, and the other end (rear end) of the second hydraulic oil passage 20d is for operating the PTO clutch 260. It communicates with a later-described third oil chamber 210a for operating the brake 210.

  The clutch mechanism 200 includes a clutch case 201, an output gear 202, a cylinder shaft 203 serving as a transmission shaft, a first multi-plate group 204, a second multi-plate group 205, a first piston 206, and a second piston 207. And comprising. The clutch mechanism 200 has a front side as a multi-plate traveling clutch 250 composed of a clutch case 201, an output gear 202, a first multi-plate group 204 and a first piston 206, and a rear side as a clutch case 201 and a cylinder shaft 203. As the multi-plate PTO clutch 260 including the second multi-plate group 205 and the second piston 207, the traveling clutch 250 and the PTO clutch 260 are integrally configured. Here, the traveling clutch 250 transmits or blocks the power of the engine 6 transmitted to the mission input shaft 20 to a traveling system power transmission structure including a belt-type continuously variable transmission 40 serving as a traveling transmission device. The clutch 250 transmits or blocks the power of the engine 6 transmitted to the mission input shaft 20 to a PTO system power transmission structure including a PTO input shaft 220 described later.

  The clutch case 201 has a double cylindrical shape, and includes an inner cylindrical portion 201a, an outer cylindrical portion 201b, and a connecting portion 201c that connects intermediate portions in the axial direction of the inner cylindrical portion 201a and the outer cylindrical portion 201b. The front space which opened the front, and the rear space which opened the back are formed. The inner cylinder portion 201a is fitted on the rear portion of the mission input shaft 20 so as not to be relatively rotatable. A spline for engaging friction plates 204A, 204A,... And friction plates 205A, 205A, which will be described later, is formed on the outer cylinder portion 201b.

  The output gear 202 is disposed in front of the clutch case 201 and is rotatably supported by the mission input shaft 20 via bearings 23 and 24. On the rear surface of the output gear 202, a cylindrical projecting portion 202a projecting rearward with a diameter larger than the inner tubular portion 201a and smaller than the outer tubular portion 201b is formed, and the projecting portion 202a is formed on the clutch case 201. It is inserted into the space on the front side surrounded by the inner cylinder part 201a, the outer cylinder part 201b, and the connecting part 201c. Splines for engaging friction plates 204B, 204B,... Described later are formed on the outer periphery of the protruding portion 202a. Further, the output gear 202 is meshed with the transmission input gear 51 so that power is transmitted to the traveling system power transmission structure including the belt type continuously variable transmission 40.

  The cylinder shaft 203 is disposed behind the clutch case 201 with the axial direction as the front-rear direction. A cylindrical projecting portion 203a projecting forward with a diameter larger than the inner tubular portion 201a and smaller than the outer tubular portion 201b is formed at the front portion of the tubular shaft 203, and the projecting portion 203a is formed in the clutch case 201. Are inserted into a rear space surrounded by the inner cylinder part 201a, the outer cylinder part 201b, and the connecting part 201c. Splines for engaging friction plates 205B, 205B... Described later are formed on the outer periphery of the protrusion 203a.

  The inner periphery of the front portion of the cylindrical shaft 203 is supported by the mission input shaft 20 via a needle bearing 25, and the outer periphery of the front portion of the cylindrical shaft 203 is supported by the transmission case 8 via the bearing 22. . Further, a spline is formed on the outer periphery of the rear portion of the support portion that supports the bearing 22, and friction plates 212A, 212A. The rear end portion of the cylindrical shaft 203 is fitted into one end 220a (front end) of the PTO input shaft 220 provided on the extension of the mission input shaft 20 so as not to be relatively rotatable.

  The first multi-plate group 204 is composed of a plurality of friction plates 204A, 204A,... On the driving side and a plurality of friction plates 204B, 204B,. Stored. The plurality of friction plates 204A, 204A,... Are arranged in parallel on the front inner peripheral surface of the outer cylinder portion 201b of the clutch case 201 so as to be slidable in the front-rear direction, and the plurality of friction plates 204B, 204B,. Are arranged in parallel on the outer peripheral surface of the protruding portion 202a of the output gear 202 so as to be slidable in the front-rear direction, and the friction plates 204A and the friction plates 204B are alternately arranged.

  The second multi-plate group 205 includes a plurality of friction plates 205A, 205A,... On the driving side and a plurality of friction plates 205B, 205B, on the driven side. Stored. The plurality of friction plates 205A, 205A,... Are arranged in parallel on the rear inner peripheral surface of the outer cylinder portion 201b of the clutch case 201 so as to be slidable in the front-rear direction, and the plurality of friction plates 205B, 205B,. Is provided on the cylindrical shaft 203. Specifically, the friction plate 205A and the friction plate 205B are arranged on the outer peripheral surface of the protruding portion 203a of the cylindrical shaft 203 so as to be slidable in the front-rear direction. Are alternately arranged.

  The first piston 206 has a substantially disc shape, and is slidably inserted in the front-rear direction in a space surrounded by the front inner cylindrical portion 201a, outer cylindrical portion 201b, and connecting portion 201c in the clutch case 201. . A first oil chamber 200a is formed between the first piston 206 and the clutch case 201, and the first oil chamber 200a communicates with the first hydraulic oil passage 20c. A pressing portion 206 a that protrudes forward is formed at the outer peripheral side end of the first piston 206. A first urging member 251 such as a spring is interposed between the inner peripheral side of the first piston 206 and the locking ring 252 provided at the end of the inner cylinder portion 201a. It is urged rearward (travel clutch 250 non-operating side).

  The second piston 207 has a substantially disk shape, and is slidably inserted in the front-rear direction in a space surrounded by the rear inner cylindrical portion 201a, outer cylindrical portion 201b, and connecting portion 201c in the clutch case 201. The A second oil chamber 200b is formed between the second piston 207 and the clutch case 201, and the second oil chamber 200b communicates with the second hydraulic oil passage 20d. A pressing portion 207 a that protrudes rearward is formed at the outer peripheral end of the second piston 207. A second urging member 261 such as a spring is interposed between the inner peripheral side of the second piston 207 and the locking ring 262 provided at the end of the inner cylinder portion 201a. It is urged forward (PTO clutch 260 non-operating side).

  A brake holder portion 8A is formed at the front upper portion of the middle case 8b, and the PTO brake 210 is accommodated in the brake holder portion 8A. The PTO brake 210 brakes the PTO input shaft 220 when power is not transmitted to the PTO input shaft 220, that is, when the PTO clutch 260 is turned off. The PTO brake 210 is disposed at the rear part of the clutch mechanism 200. The PTO brake 210 is a multi-plate brake, and includes an engaging portion 211 formed on the inner surface of the brake holder portion 8A, the cylindrical shaft 203, a third multi-plate group 212, and a third piston 213. In this manner, the PTO clutch 260 and the PTO brake 210 are configured by the cylindrical shaft 203 serving as a common transmission shaft, thereby reducing the number of parts and making the configuration compact.

  The engaging portion 211 is configured to be able to engage friction plates 212B, 212B,.

  The third multi-plate group 212 includes a plurality of friction plates 212A, 212A,... On the rotating side, and a plurality of friction plates 212B, 212B,. A plurality of friction plates 212A, 212A,... Are provided on the cylindrical shaft 203. Specifically, the friction plates 212A, 212A,. The friction plates 212B, 212B,... Are arranged in parallel on the inner peripheral surface of the engaging portion 211 so as to be slidable in the front-rear direction, and the friction plates 212A and the friction plates 212B are alternately arranged. Arranged.

  The third piston 213 has a substantially disk shape, and is externally fitted to the rear portion of the cylindrical shaft 203 so as to be slidable in the front-rear direction. A third oil chamber 210a is formed between the third piston 213 and the cylinder shaft 203, and the third oil chamber 210a communicates with the second hydraulic oil passage 20d. A pressing portion 213 a is formed on the front surface of the third piston 213. A step portion 213b is formed on the outer periphery of the third piston 213, and a third urging member 214 such as a spring is provided between the step portion 213b and the locking ring 215 provided in the brake holder portion 8A. The third piston 213 is urged forward (braking side) with respect to the brake holder portion 8A by the third urging member 214.

  The mission input shaft 20 has a lubricating oil passage (not shown) formed in parallel with the first hydraulic oil passage 20c and the second hydraulic oil passage 20d, and a first multi-plate group 204, a second multi-plate group. 205, the third multi-plate group 212 and the needle bearing 25 are configured to send oil.

  As shown in FIG. 3A, in the clutch mechanism 200 and the PTO brake 210, when the operating tool is operated so that the travel clutch 250 is “disengaged”, the first urging member 251 is attached. The pressing portion 206a of the first piston 206 is separated from the first multi-plate group 204 by the force, so that the adjacent friction plates 204A and 204B in the first multi-plate group 204 are not pressed against each other, and the clutch case 201 and the output gear 202 are separated. And do not rotate integrally. That is, power is not transmitted from the clutch case 201 to the output gear 202 and is shut off.

  When the operating tool is operated so that the PTO clutch 260 is “disengaged”, the pressing portion 207 a of the second piston 207 is separated from the second multi-plate group 205 by the biasing force of the second biasing member 261. The adjacent friction plates 205A and 205B in the second multi-plate group 205 are not pressed against each other, and the clutch case 201 and the cylindrical shaft 203 do not rotate integrally. That is, the power is not transmitted from the clutch case 201 to the cylindrical shaft 203 and is shut off.

  At the same time, the pressing portion 213a of the third piston 213 presses the third multi-plate group 212 by the urging force of the third urging member 214, and the adjacent friction plates 212A and 212B in the third multi-plate group 212 are pressed against each other. Thus, the cylinder shaft 203 is braked.

  Then, as shown in FIG. 3B, in the clutch mechanism 200 and the PTO brake 210, when the operating tool is operated so that the travel clutch 250 is turned “ON”, the hydraulic valve is switched to change the hydraulic pressure (not shown). The hydraulic oil α is sent from the pump to the first oil chamber 200a through the first hydraulic oil passage 20c, and the first piston 206 resists the biasing force of the first biasing member 251 by the hydraulic oil α. Move forward. Thus, the pressing portion 206a of the first piston 206 presses the first multi-plate group 204, and the adjacent friction plates 204A and 204B in the first multi-plate group 204 are pressed against each other, and the clutch case 201 and the output are output. The gear 202 rotates integrally. That is, power is transmitted from the clutch case 201 to the output gear 202.

  Further, when the operating tool is operated so that the PTO clutch 260 is “ON”, the hydraulic valve is switched, and the hydraulic oil β from the hydraulic pump (not shown) is supplied to the second through the second hydraulic oil passage 20d. The oil is supplied to the oil chamber 200b, and the second piston 207 moves backward against the urging force of the second urging member 261 by the hydraulic oil β. Thus, the pressing portion 207a of the second piston 207 presses the second multi-plate group 205, and the adjacent friction plates 205A and 205B in the travel clutch 250 are pressed against each other, and the clutch case 201 and the cylinder shaft 203 are Rotate together. That is, power is transmitted from the clutch case 201 to the cylinder shaft 203.

  At the same time, the hydraulic valve is switched, and hydraulic oil β is sent from a hydraulic pump (not shown) to the third oil chamber 210a via the second hydraulic oil passage 20d, and the third piston 213 is moved by the hydraulic oil β to the first piston 213. It moves backward against the urging force of the three urging members 214. Thereby, the pressing portion 213a of the third piston 213 is separated from the third multi-plate group 212, the adjacent friction plates 212A and 212B in the third multi-plate group 212 are not pressed against each other, and the cylinder shaft 203 is connected to the transmission case. 8 can rotate relative to 8. That is, the cylinder shaft 203 can be rotated.

  As described above, in the tractor 1 according to one embodiment of the present invention, the PTO input shaft 220 is disposed on the extension of the mission input shaft 20, and the power from the engine 6 serving as a drive source is used for the mission input shaft 20. In the power transmission structure of the tractor 1, which is a work vehicle configured to be transmitted to one end 20 a of the belt-type continuously variable transmission 40 and the PTO input shaft 220 from the transmission input shaft 20 as a traveling transmission device. The traveling clutch 250, the PTO clutch 260, and the PTO brake 210 are integrally disposed on the other end 20b side of the mission input shaft 20.

  As a result, the traveling clutch 250, the PTO clutch 260, and the PTO brake 210 are integrally disposed. Therefore, the traveling clutch 250, the PTO clutch 260, and the PTO only need to be separated from the front case 8a and the middle case 8b of the transmission case 8. The brake 210 appears and can be maintained at the same time, so that maintainability can be improved. Further, when the travel clutch 250, the PTO clutch 260, and the PTO brake 210 are hydraulically operated, the hydraulic oil paths can be concentrated and similarly maintainability can be improved. In addition, the traveling clutch 250, the PTO clutch 260, and the PTO brake 210 can be disposed at substantially the center of the transmission 7, and the weight balance is improved.

  The traveling clutch 250, the PTO clutch 260, and the PTO brake 210 are configured as a multi-plate type, and the friction plates 204A and 204B of the traveling clutch 250 and the friction plates 205A and 205B of the PTO clutch 260 are shared. The clutch case 201 is housed, and the friction plate 205B of the PTO clutch 260 and the friction plate 212A of the PTO brake 210 are provided on a cylindrical shaft 203 serving as a common transmission shaft.

  Thereby, the number of parts of the traveling clutch 250, the PTO clutch 260, and the PTO brake 210 can be reduced. Further, the travel clutch 250, the PTO clutch 260, and the PTO brake 210 can be configured in a compact manner.

  Hereinafter, the power transmission structure from the PTO input shaft 220 to the rear PTO shaft 230 and the mid PTO shaft 240 will be described in detail with reference to FIG.

  A PTO transmission portion 8B is formed in the rear portion of the mission case 8, more specifically, in the space between the middle case 8b and the rear case 8c of the mission case 8. The PTO transmission unit 8B includes a PTO input shaft 220, a rear PTO shaft 230, a speed reduction mechanism 270, an idle gear 235, a mid PTO shaft 240, a mid PTO clutch 290, and the like.

  The PTO input shaft 220 is arranged with the axial direction as the front-rear direction, and the rear part thereof is supported by the middle case 8b and the rear case 8c via bearings 221 and 222. A drive gear 223 is fixed to the other end 220 b (rear end) of the PTO input shaft 220. Alternatively, it is formed integrally with the PTO input shaft 220.

  The rear PTO shaft 230 is disposed with the axial direction as the front-rear direction, and the front portion thereof is supported by the middle case 8b and the rear case 8c via bearings 231,232. A driven gear 233 that meshes with the drive gear 223 is fixed to one end 230 a (front end) of the rear PTO shaft 230. The other end 230b (rear end) of the rear PTO shaft 230 protrudes rearward from the mission case 8 (rear case 8c) and can be connected to the input shaft of the work implement via a universal joint or the like.

  The driven gear 233 has a diameter larger than that of the drive gear 223, and the drive gear 223 and the driven gear 233 form a speed reduction mechanism 270 to reduce the power transmitted to the drive gear 223. The driven gear 233 is meshed with the idle gear 235. The idle gear 235 has substantially the same diameter as the driven gear 233 and is supported by the middle case 8b and the rear case 8c via bearings 236 and 237.

  The mid PTO shaft 240 is arranged with the axial direction as the front-rear direction, and a midway portion thereof is supported by the middle case 8b via the bearing 241 and a rear portion thereof is supported by the rear case 8c via the bearing 242. A transmission gear 243 is rotatably fitted to one end 240a (rear end) of the mid PTO shaft 240, and a shifter 244 is relatively rotated in front of the transmission gear 243 and in the middle of the mid PTO shaft 240. It is impossible to fit outside. The other end 240 b (front end) of the mid PTO shaft 240 protrudes forward from the mission case 8. Specifically, a rear wall 8d is formed at the rear part of the middle case 8b, and the lower part of the rear wall 8d and the rear case 8c protrudes to the side from the front side surface of the middle case 8b. The other end 240b of the mid PTO shaft 240 protrudes forward.

  A spline 240c parallel to the axial direction is formed on the outer peripheral surface of the mid PTO shaft 240 in the middle of the case. A through hole 240d perpendicular to the axial direction is formed on the spline 240c. Two hard balls 245 and 245 and a biasing member (not shown) interposed between the two hard balls 245 and 245 are fitted into the through hole 240d.

  The transmission gear 243 has a cylindrical shape, and a tooth portion 243a is formed at the rear portion thereof. The tooth portion 243a meshes with the idle gear 235. The tooth portion 243a has a smaller diameter than the idle gear 235, and the idle gear 235 and the transmission gear 243 form a speed increasing mechanism 280 to increase the speed of the power transmitted to the idle gear 235. In addition, a spline portion 243 b is formed at the front portion of the transmission gear 243.

  The shifter 244 is slidable with respect to the mid PTO shaft 240 and is fitted so as not to be relatively rotatable. That is, the shifter 244 has a cylindrical shape, and a spline groove 244a that engages with the spline 240c of the mid PTO shaft 240 and the spline portion 243b of the transmission gear 243 is formed on the inner peripheral surface thereof in parallel to the axial direction. Is done. The spline grooves 244a are formed with front and rear ring-shaped grooves 244b and 244c that engage with the two hard spheres 245 and 245, respectively.

  The transmission gear 243 and the shifter 244 form a mid PTO clutch 290. That is, when the operating tool is operated so that the mid PTO clutch 290 is “disconnected”, the shifter 244 slides forward, and the two hard balls 245 and 245 engage with the ring-shaped groove 244b on the front side of the shifter 244. Match. Thereby, the spline groove 244a of the shifter 244 is not engaged with the spline part 243b of the transmission gear 243, and the shifter 244 and the transmission gear 243 do not rotate integrally. That is, power is not transmitted from the transmission gear 243 to the shifter 244 and is blocked.

  Further, when the operation tool is operated so that the mid PTO clutch 290 is “on”, the shifter 244 slides rearward, and the two hard balls 245 and 245 are connected to the ring-shaped groove 244 c on the rear side of the shifter 244. Engage. Thereby, the spline groove 244a of the shifter 244 is engaged with the spline portion 243b of the transmission gear 243, and the shifter 244 and the transmission gear 243 rotate integrally. That is, power is transmitted from the transmission gear 243 to the shifter 244.

  In such a power transmission structure from the PTO input shaft 220 to the rear PTO shaft 230 and the mid PTO shaft 240, the power transmitted to the PTO input shaft 220 is transmitted to the rear PTO shaft 230 via the speed reduction mechanism 270. The On the other hand, the power transmitted to the rear PTO shaft 230 is transmitted from the rear PTO shaft 230 to the mid PTO shaft 240 via the speed increasing mechanism 280 and the mid PTO clutch 290. Thus, the speed reduction mechanism 270 that reduces the power of the rear PTO shaft 230 is also used as a speed reduction mechanism that reduces the power of the mid PTO shaft 240, thereby reducing the number of parts. Note that the speed reduction mechanism 270 may be a variable speed mechanism constituted by a gear train or the like.

  Then, when driving the working machine mounted on the rear part of the vehicle body, the PTO clutch 260 is set to “ON”, the PTO brake 210 is set to “OFF”, and power is transmitted to the rear PTO shaft 230 for driving. When driving a work machine attached to the lower center of the vehicle body such as the midmore 10, the PTO clutch 260 is set to “ON”, the PTO brake 210 is set to “OFF”, and the mid PTO clutch 290 is set to “ON”. Power is transmitted and driven.

  Note that a rear PTO clutch may be provided at one end 230a of the rear PTO shaft 230 or the like. In such a case, the rear PTO clutch and the mid PTO clutch 290 are interlocked to operate reversely (for example, if the rear PTO clutch is “ON”, the mid PTO clutch 290 is “OFF”). It is desirable to make it so.

  Further, by disassembling the rear case 8c of the mission case 8 with respect to the middle case 8b, maintenance in the PTO transmission portion 8B can be easily performed. That is, simply by removing the rear case 8c of the transmission case 8, the speed reduction mechanism 270, the rear PTO shaft 230, the speed increasing mechanism 280, the mid PTO shaft 240, the mid PTO clutch 290, etc. appear, so that these assembly and maintenance can be performed. It can be done easily.

  Further, since the power transmission structure of the work system is centrally arranged in the PTO transmission portion 8B, maintenance of the power transmission structure of the work system can be easily performed. That is, it is possible to improve the maintainability by separating the power transmission structure of the traveling system and the power transmission structure of the work system.

  As described above, in the tractor 1 according to one embodiment of the present invention, the PTO transmission portion 8B is formed in the rear portion of the transmission case 8, and the rear PTO shaft 230 and the mid PTO shaft 240 are supported by the PTO transmission portion 8B. A power transmission structure for the tractor 1 serving as a work vehicle, which transmits power from the PTO input shaft 220 to the rear PTO shaft 230 via the speed reduction mechanism 270 and from the rear PTO shaft 230 via the mid PTO clutch 290. Thus, power can be transmitted to the mid PTO shaft 240.

  As a result, the speed reduction mechanism 270 that decelerates the power of the rear PTO shaft 230 can also be used as a speed reduction mechanism that decelerates the power of the mid PTO shaft 240, thereby reducing the number of parts.

1 Tractor (work vehicle)
6 Engine (drive source)
7 Transmission 8 Mission case 20 Mission input shaft (input shaft)
40 Belt type continuously variable transmission (travel transmission)
200 Clutch mechanism 201 Clutch case 203 Tube shaft (transmission shaft)
204A friction plate (friction plate on the driving side of the traveling clutch)
204B Friction plate (Friction plate on the driven side of the traveling clutch)
205A Friction plate (Friction plate on the drive side of the PTO clutch)
205B Friction plate (Friction plate on the driven side of the PTO clutch)
210 PTO brake 212A Friction plate (PTO brake rotating friction plate)
212B Friction plate (Friction plate on the fixed side of the PTO brake)
220 PTO input shaft 230 Rear PTO shaft 240 Mid PTO shaft 250 Traveling clutch 260 PTO clutch 270 Reduction mechanism 290 Mid PTO clutch

Claims (1)

  1. A power transmission structure for a work vehicle in which a PTO transmission is formed at the rear of the transmission case, and a rear PTO shaft and a mid PTO shaft are supported on the PTO transmission,
    A work vehicle configured to transmit power from the PTO input shaft to the rear PTO shaft via a speed reduction mechanism and to transmit power from the rear PTO shaft to the mid PTO via a mid PTO clutch. Power transmission structure.
JP2010250358A 2010-11-08 2010-11-08 Power transmission structure for working vehicle Pending JP2012101614A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2010250358A JP2012101614A (en) 2010-11-08 2010-11-08 Power transmission structure for working vehicle

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2010250358A JP2012101614A (en) 2010-11-08 2010-11-08 Power transmission structure for working vehicle

Publications (1)

Publication Number Publication Date
JP2012101614A true JP2012101614A (en) 2012-05-31

Family

ID=46392572

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2010250358A Pending JP2012101614A (en) 2010-11-08 2010-11-08 Power transmission structure for working vehicle

Country Status (1)

Country Link
JP (1) JP2012101614A (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5094633U (en) * 1973-12-13 1975-08-08
JPS619327U (en) * 1984-06-22 1986-01-20
JPH02274627A (en) * 1989-04-17 1990-11-08 Kubota Corp Pto shaft device for tractor
JP2004231050A (en) * 2003-01-30 2004-08-19 Kanzaki Kokyukoki Mfg Co Ltd Frame structure body of vehicle

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5094633U (en) * 1973-12-13 1975-08-08
JPS619327U (en) * 1984-06-22 1986-01-20
JPH02274627A (en) * 1989-04-17 1990-11-08 Kubota Corp Pto shaft device for tractor
JP2004231050A (en) * 2003-01-30 2004-08-19 Kanzaki Kokyukoki Mfg Co Ltd Frame structure body of vehicle

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