JP4362196B2 - Tracked tractor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an arrangement configuration of a power transmission device for a crawler tractor.
[0002]
[Prior art]
Conventionally, a power transmission mechanism of a crawler tractor has been publicly known. For example, in the technique disclosed in Japanese Patent Laid-Open No. 8-104150, a front PTO transmission case is disposed at the rear of an engine, and a pair of HSTs for running and turning at the rear thereof. (Hydraulic continuously variable transmission) hydraulic pump is arranged, rear PTO transmission case is arranged behind it, and HST hydraulic motors are respectively installed on the parts that support the rotating shafts of the left and right drive sprockets of the crawler type traveling device It was arranged.
[0003]
[Problems to be solved by the invention]
However, in the prior art as described above, since the hydraulic pump and the hydraulic motor constituting the HST are separately arranged, hydraulic piping is required, and since the sprocket is directly driven by the hydraulic motor, the hydraulic pump and the hydraulic motor have a capacity. There was a need for something big. In addition, a technology for integrally providing the HST in the rear mission case is also known, but since a commercially available HST cannot be used, a dedicated hydraulic pump and hydraulic motor have to be designed, resulting in an increase in cost. .
[0004]
[Means for Solving the Problems]
The present invention uses the following means in order to solve the above problems.
[0005]
The engine (3) is disposed above the front portion of the crawler type traveling device (1), and a front mission case (16) is fixed to the front end portion of the crawler type traveling device (1). ) Directly support the drive sprocket (11) that drives the left and right crawler belts (14), and a damper case (19) is fixed to the rear of the engine (3). The damper case (19) In a crawler tractor in which a traveling HST (22) is attached to the rear side of the crawler traveling device (1), and a rear transmission case (5) is disposed at the rear of the traveling HST (22). The turning HST (20) is attached to the front surface of the front transmission case (16), and the turning HST (20) is constituted by a hydraulic pump (121) and a hydraulic motor (124). Then, the movable swash plate of the hydraulic pump (121) is linked to the steering handle (7), and the engine is connected to the input shaft (134) of the input speed reduction mechanism (132) configured in the front transmission case (16). Rotation is input, and after being decelerated by the input deceleration mechanism (132), the rotation is input to the hydraulic pump (121), and the rotation of the output shaft (125) of the hydraulic motor (124) is changed to the tip bevel gear (126), This is transmitted to the planetary gear mechanism (140) in the front mission case (16) via the left and right bevel gears (127, 127) meshing with the bevel gear (126), and rotated after the shift by the rear mission case (5). From the output shaft (57) provided in the lower part through the universal joint (60) and the input shaft protruding rearward from the front mission case (16) 61), a bevel gear (141) is fixed on an input shaft (61) in the front mission case (16), and the bevel gear (141) is constituted by the planetary gear mechanism (140). The gear is engaged with a bevel gear (142) fixed on a sun gear shaft (143) of a differential gear to transmit power, and an input speed reduction mechanism (132) and a planetary gear mechanism (140) are connected to the front mission case (16). ) And the left and right final reduction gears (133), and the final reduction gears (149) configured by a gear train on the drive output shaft (149) fixed to the output gear (147) of the planetary gear mechanism (140). 133), and the drive sprocket (11) is fixed directly on the output shaft protruding from the final reduction gear (133) .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The problems and means to be solved by the present invention are as described above. Next, an embodiment of the present invention shown in the accompanying drawings will be described.
[0007]
1 is a side view of a crawler tractor according to an embodiment of the present invention, FIG. 2 is a side view showing an arrangement of an engine, an HST, and a transmission case, and FIG. 3 is a skeleton diagram showing a drive transmission path.
[0008]
First, a schematic configuration of a crawler tractor which is an embodiment provided with a power transmission mechanism according to the present invention will be described. As shown in FIG. 1, an engine 3 is disposed above the front portion of the crawler traveling device 1, and a rear mission case 5 is disposed above the rear portion. The engine 3 is covered with a bonnet 4, and the engine 3 is fixed between the left and right engine brackets 6 and 6. A steering column 2 is provided at the rear portion of the bonnet 4, a steering handle 7 for performing a steering operation is disposed on the steering column 2, and a seat 8 is disposed behind the steering handle 7. Step 18 is arranged below between the seat 8 and the seat 8 to constitute an operation unit. These operating parts are covered with a cabin 9. In addition, a three-point link type mounting device 10 for mounting various working machines is provided at the rear end of the vehicle.
[0009]
The crawler type traveling device 1 is supported by a crawler frame 15, a front mission case 16 is fixed to a front end portion of the crawler frame 15 to support a drive sprocket 11, and an idler 12 and a rear end portion thereof. The rollers 13, 13... Are rotatably supported between the drive sprocket 11 and the idler 12, and the periphery of the drive sprocket 11, the idler 12, and the rollers 13, 13. ing.
[0010]
Next, the drive transmission system of the crawler tractor will be described with reference to FIGS. A traveling hydraulic continuously variable transmission (hereinafter referred to as “traveling HST”) 22 is attached to the rear portion of the engine 3 via a damper case 19, and an auxiliary transmission 43, a PTO transmission 44, and the like are accommodated behind the traveling HST 22. The rear transmission case 5 is disposed, and the output of the traveling HST 22 is transmitted to the auxiliary transmission 43 via the auxiliary transmission input shaft 48, and is transmitted to the PTO transmission 44 via the transmission shaft 42. It is possible to easily change to a wheel type tractor by arranging a main transmission such as a hydraulic clutch type, HST type or gear sliding type between the engine 3 and the rear transmission case 5. Changes can be made easily, more parts can be used, less design changes, and cost reduction.
[0011]
Further, a front transmission case 16 provided with a turning hydraulic continuously variable transmission (hereinafter referred to as turning HST) 20 is disposed in front of the engine 3 and is supported at the front of the engine bracket 6 and disposed at the front position of the airframe. is doing. The turning HST 20 is driven by the power from the engine 3, and the output of the turning HST 20 and the output from the auxiliary transmission 43 are combined to drive the drive sprocket 11. As described above, the traveling HST 22, the rear transmission case 5 housing the auxiliary transmission 43 and the PTO transmission 44, and the turning HST 20 are independently arranged, and maintenance and the like can be performed separately. It can be changed easily.
[0012]
Next, a specific configuration of the power transmission configuration will be described. The crankshaft of the engine 3 is disposed horizontally in the front-rear direction and protrudes forward and rearward. The rear output shaft 3a is input to the traveling HST 22 via the damper 21, and the traveling HST 22 is connected to the rear portion of the engine 3 via the damper case 19, and the traveling HST 22 is below the steering column 2, that is, a step. The space below the step 18 is effectively used. The input shaft 23 of the traveling HST 22 extends rearward through the traveling HST 22, and the rear end of the input shaft 23 is input to the PTO clutch 24 housed in the rear mission case 5. The output is transmitted to the PTO input shaft 26 via the transmission shaft 25, and a PTO first speed gear 27, a PTO second speed gear 28 and a PTO reverse gear 29 are fixed on the PTO input shaft 26.
[0013]
A reverse shaft 30, a PTO transmission shaft 31, a counter shaft 33, and a PTO shaft 34 are supported in parallel with the PTO input shaft 26. On the PTO transmission shaft 31, a PTO 1-speed driven gear 35, a PTO 2-speed driven gear 36, and a PTO A reverse driven gear 37 is loosely fitted. The PTO first speed driven gear 35 is connected to the PTO first speed gear 27, the PTO second speed driven gear 36 is connected to the PTO second speed gear 28, and the PTO reverse speed driven gear 37 is connected to the reverse gear 38 on the reverse shaft 30. Are meshed with the PTO reverse gear 29, respectively.
[0014]
A sliding gear 39 is slidably spline-fitted on the PTO transmission shaft 31, and the PTO first speed driven gear 35, the PTO second speed driven gear 36, the PTO reverse rotation driven gear 37 and the PTO speed change lever are respectively rotated. The PTO transmission 44 is configured to enable meshing and to enable PTO speed change. A transmission gear 40 is further fixed on the PTO transmission shaft 31, and the transmission gear 40 can transmit power to a gear 41 fixed on the PTO shaft 32 via a counter gear on the counter shaft 33. It is said. The PTO shaft 32 projects rearward and can drive a work machine connected to the rear end of the traveling vehicle.
[0015]
The traveling HST 22 includes a variable displacement hydraulic pump 45 and a constant displacement hydraulic motor 46, and a movable swash plate of the hydraulic pump 45 is connected to a speed change arm 63 provided on a side surface of the traveling HST 22. The speed change arm 63 is interlocked and connected to a main speed change lever 65 provided in the operating portion via a link mechanism, and the discharge amount and the direction of discharge from the hydraulic pump 45 are changed by the rotation of the main speed change lever 65 so as to change the hydraulic motor 46. The number of rotations and the direction of rotation can be changed. That is, the main speed change is possible.
[0016]
An output shaft 47 of the hydraulic motor 46 is connected to a sub-transmission input shaft 48 that is supported by the rear transmission case 5, and a high-speed gear 50 and a low-speed gear 51 are fixed on the sub-transmission input shaft 48. The high-speed driven gear 53 and the low-speed driven gear 54 that are loosely fitted on the auxiliary transmission shaft 52 that is mounted in parallel with the shaft 48 are engaged with each other. A sliding gear 55 is spline-fitted between the high-speed driven gear 53 and the low-speed driven gear 54 on the auxiliary transmission shaft 52 so that a high / low speed change is possible by operating an auxiliary transmission lever or a switch (not shown). The auxiliary transmission 43 is configured.
[0017]
A transmission gear 56 is fixed on the auxiliary transmission shaft 52, and the transmission gear 56 is engaged with a gear 58 fixed on the output shaft 57. The front end of the output shaft 57 protrudes forward from the rear mission case 5 and is transmitted to the input shaft 61 protruding rearward from the front mission case 16 via the universal joint 60 and the transmission shaft. A brake device 62 is disposed on the input shaft 61 in the front mission case 16, and a bevel gear 141 is fixed to the other end of the input shaft 61, and the bevel gear 141 is configured by a planetary gear mechanism 140. It is meshed with a bevel gear 142 fixed on the sun gear shaft 143 of the apparatus.
[0018]
On the other hand, the front mission case 16 is fixed in the middle of the front and rear of the engine bracket 6, and the front mission case 16 houses the planetary gear mechanism 140, the left and right final reduction gears 133 and 133, and the input reduction mechanism 132. A turning HST 20 is attached to the front surface of the case 16. Drive sprockets 11 and 11 are fixed on the output shafts protruding from the final reduction gears 133 and 133, respectively.
[0019]
An input shaft 134 of the input speed reduction mechanism 132 is connected to an output shaft 3b protruding forward from the engine 3 via a universal joint 135. The input speed reduction mechanism 132 is decelerated by a plurality of gears, and its output is the turning HST20. The turning HST 20 is composed of a variable displacement type hydraulic pump 121 and a fixed displacement type hydraulic motor 124, and the movable swash plate of the hydraulic pump 121 is turned. The transmission arm 64 is connected to a shift arm 64 provided on the side surface of the case HST 20, and the shift arm 64 is linked to the steering handle 7, and the discharge amount from the hydraulic pump 121 according to the operation amount of the steering handle 7. Is adjusted, and the number of rotations and the direction of rotation of the output shaft 125 of the hydraulic motor 124 driven according to the discharge amount of the hydraulic pump 121 are changed. It's to be.
[0020]
The output shaft 125 of the hydraulic motor 124 extends to the rear side of the turning HST 20 and a bevel gear 126 is fixed to the tip of the output shaft 125. The bevel gear 126 meshes with the left and right bevel gears 127 and 127, and reversely rotates to the left and right. Tell. A rotational driving force is transmitted from the bevel gears 127 and 127 to the planetary gear mechanism 140.
[0021]
Next, the configuration of the planetary gear mechanism 140 will be described. In addition, since it is comprised symmetrically, one side is demonstrated. The output of the engine 3 is input from the rear mission case 5 to the front mission case 16. The driving force of the input shaft 61 is transmitted to the sun gear shaft 143 through the bevel gears 141 and 142. Then, the rotational output of the sun gear shaft 143 is transmitted to the left and right and input to the left and right planetary gear mechanisms 140 and 140. The left and right planetary gear mechanism 140 includes a sun gear 144, a planetary gear 145, a carrier 146, an output gear 147, and the like.
[0022]
The rotational output of the sun gear shaft 143 drives the sun gear 144 fixed to the left and right ends of the sun gear shaft 143 in the same direction and at the same rotational speed. The sun gear 144 meshes with one of the two gears engraved on the planetary gear 145, and the other gear 145 b meshes with the output gear 147. Here, the planetary gear 145 is rotatably supported on a shaft protruding from a carrier 146 loosely fitted on the sun gear shaft 143, and the carrier 146 is on the outer periphery of the sun gear shaft 143 (drive output shaft 149). Rotate. A gear 155 is formed on the outer periphery of the carrier 146, and the gear 155 meshes with a gear 154 fixed on a shaft 153 for fixing the bevel gear 127.
[0023]
In the above configuration, when the operation by the steering handle 7 is maintained at the neutral position, the output shaft 125 of the hydraulic motor 124 of the turning HST 20 is not rotationally driven. The bevel gear 126 is fixed, and the bevel gears 127 and 127 and the gears 154 and 154 fixed on the shafts 153 and 153 are also fixed. Is generated. As a result, the carriers 146 and 146 maintain a substantially fixed state without rotating on the sun gear shaft 143.
[0024]
Thereby, the rotational drive of the sun gear 144 is transmitted through the planetary gear 145 that is rotatably supported by the fixed carrier 146. The left and right drive output shafts 149 and 149 are rotationally driven by rotationally driving the output gear 147 that meshes with the gear 145b of the planetary gear 145. That is, when the steering handle 7 holds the neutral position, only the output from the engine 3 via the rear mission case 5 is input to the planetary gear mechanism 140, and the left and right drive output shafts 149 and 149 are connected. It is rotationally driven in the same direction and at the same rotational speed.
[0025]
On the other hand, when the steering handle 7 is turned left and right, the discharge amount of the hydraulic pump 124 of the turning HST 20 is adjusted according to the amount of operation of the steering handle 7, and the output shaft 125 of the hydraulic motor 124 is driven to rotate in accordance with this. Is done. Then, the rotation output input to the planetary gear mechanism 140 by the output shaft 125 causes the bevel gears 152 and 152 fixed on the left and right turning reverse shafts 153 and 153 to rotate reversely to each other via the bevel gear 126. Rotation is driven at the rotation speed
[0026]
As a result, the left and right carriers 146 and 146 that mesh with the gears 154 and 154 also rotate in the reverse direction and rotate around the outer periphery of the sun gear shaft 143 at the same rotational speed. The planetary gears 145 and 145 are integrated with the carriers 146 and 146 by the rotation of the carriers 146 and 146, and rotate reversely on the outer periphery of the sun gear shaft 143 at the same rotational speed. If the rotation direction of the planetary gears 145 and 145 relative to the carriers 146 and 146 is opposite to the rotation direction of the planetary gears 145 and 145 relative to the sun gear shaft 143, the rotation speeds of the output gears 149 and 149 are added. If the direction is the same, the rotational speeds of the output gears 149 and 149 are subtracted.
[0027]
That is, the output from the engine 3 after being shifted by the traveling HST 22 and the auxiliary transmission 43 and the output of the engine 3 via the turning HST 20 are combined by the planetary gear mechanism 140, and the steering handle 7 is neutral. When the vehicle travels straight and rotates left and right, a difference in rotation occurs between the left and right drive output shafts 149 and 149, thereby causing a difference in rotation between the drive sprockets 11 and 11 of the left and right crawler type traveling devices 1, and leftward or rightward. Can be turned. In this way, the vehicle moves forward or backward at the traveling speed set by the main speed change lever 65, and the rotational speed of the left and right crawlers is changed by the rotational operation of the steering handle 7, so that the driving on one side is not stopped. Thus, the crawlers on both sides can be rotated while being rotated.
[0028]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
The engine (3) is disposed above the front portion of the crawler type traveling device (1), and a front mission case (16) is fixed to the front end portion of the crawler type traveling device (1). ) Directly support the drive sprocket (11) that drives the left and right crawler belts (14), and a damper case (19) is fixed to the rear of the engine (3). The damper case (19) In a crawler tractor in which a traveling HST (22) is attached to the rear side of the crawler traveling device (1), and a rear transmission case (5) is disposed at the rear of the traveling HST (22). The turning HST (20) is attached to the front surface of the front transmission case (16), and the turning HST (20) is constituted by a hydraulic pump (121) and a hydraulic motor (124). Then, the movable swash plate of the hydraulic pump (121) is linked to the steering handle (7), and the engine is connected to the input shaft (134) of the input speed reduction mechanism (132) configured in the front transmission case (16). Rotation is input, and after being decelerated by the input deceleration mechanism (132), the rotation is input to the hydraulic pump (121), and the rotation of the output shaft (125) of the hydraulic motor (124) is changed to the tip bevel gear (126), This is transmitted to the planetary gear mechanism (140) in the front mission case (16) via the left and right bevel gears (127, 127) meshing with the bevel gear (126), and rotated after the shift by the rear mission case (5). From the output shaft (57) provided in the lower part through the universal joint (60) and the input shaft protruding rearward from the front mission case (16) 61), a bevel gear (141) is fixed on an input shaft (61) in the front mission case (16), and the bevel gear (141) is constituted by the planetary gear mechanism (140). The gear is engaged with a bevel gear (142) fixed on a sun gear shaft (143) of a differential gear to transmit power, and an input speed reduction mechanism (132) and a planetary gear mechanism (140) are connected to the front mission case (16). ) And the left and right final reduction gears (133), and the final reduction gears (149) configured by a gear train on the drive output shaft (149) fixed to the output gear (147) of the planetary gear mechanism (140). 133) and the drive sprocket (11) is fixed directly on the output shaft projecting from the final reduction gear (133), so that the traveling HST (22) and the auxiliary transmission (43) When The rear mission case (5) that houses the PTO transmission (44) and the turning HST (20) can be arranged independently to perform maintenance separately.
In addition, it is possible to easily change the specifications.
Further, a general-purpose HST can be used as the traveling HST (22), and the cost can be reduced.
[0029]
A rear transmission case (5) in which the traveling HST (22) is disposed at the rear of the engine (3) and the gap (43) and the PTO transmission (44) are housed behind the traveling HST (22). ) And the turning HST (20) is arranged at the front of the vehicle, so that the front-rear weight balance is improved.
Further, the number of hydraulic pipes can be reduced, and the rear mission case (5) can also be used as a wheel-type tractor mission case, thereby reducing costs.
[Brief description of the drawings]
FIG. 1 is a side view of a crawler tractor according to an embodiment of the present invention.
FIG. 2 is a side view showing an arrangement of an engine, an HST, and a mission case.
FIG. 3 is a skeleton diagram showing a drive transmission path.
[Explanation of symbols]
3 Engine 5 Mission case 18 Step 20 Turning HST
22 HST for driving
43 Sub-transmission 44 PTO transmission

Claims (1)

The engine (3) is disposed above the front portion of the crawler type traveling device (1), and a front mission case (16) is fixed to the front end portion of the crawler type traveling device (1). The drive sprocket (11) for driving the left and right crawler belts (14) is directly supported, and a damper case (19) is fixed to the rear part of the engine (3), and the damper case (19) is fixed to the damper case (19). In a crawler tractor in which a traveling HST (22) is attached, separated from the rear of the traveling HST (22), and a rear transmission case (5) is disposed above the rear part of the crawler traveling device (1), A turning HST (20) is attached to the front surface of the front mission case (16), and the turning HST (20) is constituted by a hydraulic pump (121) and a hydraulic motor (124). The movable swash plate of the hydraulic pump (121) is linked to the steering handle (7), and the engine rotates on the input shaft (134) of the input speed reduction mechanism (132) configured in the front mission case (16). Is input to the hydraulic pump (121) after being decelerated by the input deceleration mechanism (132), and the rotation of the output shaft (125) of the hydraulic motor (124) It is transmitted to the planetary gear mechanism (140) in the front mission case (16) via the left and right bevel gears (127, 127) meshing with the bevel gear (126), and the rear mission case (5) rotates after the speed change. The input shaft (57) projecting rearward from the front transmission case (16) through the universal joint (60) from the output shaft (57) provided in the lower part 1), a bevel gear (141) is fixed on an input shaft (61) in the front mission case (16), and the bevel gear (141) is constituted by the planetary gear mechanism (140). The gear is engaged with a bevel gear (142) fixed on a sun gear shaft (143) of a differential gear to transmit power, and an input speed reduction mechanism (132) and a planetary gear mechanism (140) are connected to the front mission case (16). ) And the left and right final reduction gears (133), and the final reduction gears (149) configured by a gear train on the drive output shaft (149) fixed to the output gear (147) of the planetary gear mechanism (140). 133) The crawler tractor characterized in that the drive sprocket (11) is fixed directly on the output shaft that is transmitted to 133) and protrudes from the final reduction gear (133) .

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