JP2012062925A - Transmission device of tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively transmit a driving force for backing to a travel device with a proper transmission efficiency, while transmitting a driving force for advancing in a wide speed range to the travel device.SOLUTION: A planetary transmission unit 30 is constituted to output the driving force for advancing even when a hydrostatic continuously variable transmission unit 11 is shifted to either of a positive rotation speed change state and a negative rotation speed change state. A low-speed transmission clutch 45 for integrally and rotatably connecting a low-speed-side variable speed gear 41 engaged with a low-speed-side output gear 31 of the planetary transmission unit 30 to a countershaft 44; and a high-speed transmission clutch 46 for integrally and rotatably connecting a high-speed-side variable speed gear 42 engaged with a high-speed-side output gear 32 of the planetary transmission unit 30 to the countershaft 44 are provided. An output shaft gear 48 engaged with a counter gear 47 integrally and rotatably supported by the countershaft 44 is provided. A retreat transmission clutch 52 for integrally and rotatably connecting a retreat transmission gear 51 engaged with the low-speed-side output gear 31 to an output shaft 43 is provided.

Description

  The present invention includes a hydrostatic continuously variable transmission unit that inputs driving force from an engine, and a planetary transmission unit that combines and outputs the driving force output from the hydrostatic continuously variable transmission unit and the driving force from the engine. The present invention also relates to a transmission device for a tractor including a traveling transmission unit that transmits an output of the planetary transmission unit to a traveling device.

As a transmission device for the tractor described above, there has conventionally been one described in Patent Document 1, for example. In the one described in Patent Document 1, a traveling transmission unit is configured including a shift output unit that inputs an output from the planetary transmission unit and a forward / reverse switching device that inputs an output from the shift output unit. .
That is, in the one described in Patent Document 1, the shift output unit is configured to include a first speed clutch, a second speed clutch, a third speed clutch, and a fourth speed clutch, and accompanying the shift control of the hydrostatic continuously variable transmission unit. The 1st speed clutch, 2nd speed clutch, 3rd speed clutch and 4th speed clutch are appropriately switched between the on state and the disengaged state, so that the output from the planetary transmission unit is in 4 stages from the 1st speed range to the 4th speed range The speed range is divided into stages, and the speed is steplessly changed in each speed range and transmitted to the traveling device via the forward / reverse switching device. The forward / reverse switching device includes a forward clutch and a reverse clutch. When the forward clutch is switched to an engaged state, the output from the speed change output unit is converted into a driving force on the forward side. When the reverse clutch is switched to the engaged state, the output from the shift output portion is converted into the reverse drive force and transmitted to the traveling device.

JP 2008-25803 A

  By applying the above-described conventional technology, when the traveling device can be driven forward and backward, the output from the planetary transmission unit is divided into a plurality of speed ranges and transmitted to the traveling device. In addition to having a speed range setting section as a speed change processing section for shifting the output from the planetary transmission section, the forward transmission state and the traveling apparatus are used for transmission so that the driving force transmitted to the traveling apparatus becomes the forward driving force. Therefore, it is necessary to provide a forward / reverse switching device which can be switched to a reverse transmission state for transmission so that the driving force transmitted to the reverse driving force becomes high, and the cost is high.

  If the hydrostatic continuously variable transmission section is configured to use the function of outputting the driving force in the reverse rotation direction as a function of transmitting the driving force for the reverse drive to the traveling device, the reverse drive device is provided without the forward / reverse switching device. Can be transmitted to the traveling device. In this case, the power loss tends to be large because the transmission efficiency of the hydrostatic continuously variable transmission is not very good.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a tractor capable of transmitting a forward drive force having a wide speed range to a traveling device while transmitting a backward drive force to the traveling device at a low cost and in a high transmission efficiency. It is to provide a transmission device.

According to the first aspect of the present invention, a hydrostatic continuously variable transmission unit that inputs driving force from an engine, and a planetary transmission that combines and outputs the driving force output from the hydrostatic continuously variable transmission unit and the driving force from the engine. A transmission device for a tractor including a traveling portion for transmitting the output of the planetary transmission portion to a traveling device,
In the state where the planetary transmission unit is shifted to either the forward rotational speed state where the hydrostatic continuously variable transmission portion outputs the driving force in the forward rotational direction or the reverse rotational speed state where the driving force in the reverse rotational direction is output. Is configured to output the driving force for forward movement,
The driving power output from the planetary power transmission unit is divided into a plurality of speed ranges, and the multi-speed transmission state and the power output as the driving power are stopped. A speed range setting unit that can be shifted in a neutral state, a reverse transmission state in which the forward driving force output from the planetary transmission unit is converted into a reverse driving force, and a neutral state in which transmission is stopped. There is a reverse transmission that can be switched to
The planetary transmission unit is provided with a low speed side output gear and a high speed side output gear,
A low-speed side transmission gear that is supported by the counter shaft so as to be relatively rotatable while meshed with the low-speed side output gear, and a high-speed side that is supported by the counter shaft while being meshed with the high-speed side output gear. A transmission gear, a counter gear that is rotatably supported by the counter shaft, an output shaft gear that is rotatably supported by the output shaft while meshing with the counter gear, and the low-speed transmission gear are used as the counter shaft. A low-speed transmission clutch that can be switched between an engaged state in which the low-speed side transmission gear is connected to be freely rotatable and a cut-off state that allows relative rotation of the low-speed side transmission gear with respect to the counter shaft, A high-speed transmission clutch that can be switched between a connected engagement state and a cut-off state that enables relative rotation of the high-speed side transmission gear with respect to the counter shaft; Configure the Nji setting section,
A reverse transmission gear that is rotatably supported by the output shaft in mesh with the low-speed side output gear, a closed state in which the reverse transmission gear is connected to the output shaft so as to be integrally rotatable, and the reverse transmission gear. The reverse transmission clutch is provided with a reverse transmission clutch that enables relative rotation with respect to the output shaft.

  According to the configuration of the first aspect of the present invention, the forward drive force is output from the planetary transmission portion regardless of whether the hydrostatic continuously variable transmission portion is shifted to either the forward rotation speed change state or the reverse rotation speed change state. When the speed range setting unit is shifted to the shift transmission state and the reverse transmission unit is shifted to the neutral state, the forward driving force output from the planetary transmission unit remains the forward driving force, and the traveling device It is transmitted to. In this case, the low-speed transmission clutch and the high-speed transmission clutch of the speed range setting unit are appropriately switched between the on state and the off state in accordance with the shift control of the hydrostatic continuously variable transmission unit, and are output from the planetary transmission unit. Even if the forward driving force is divided into two speed ranges, the first speed range and the second speed range, by the speed range setting unit, the first speed range and the second speed range. As the hydrostatic continuously variable transmission is controlled to shift, the forward driving force transmitted to the travel device is shifted steplessly. On the other hand, when the speed range setting unit is shifted to the neutral state and the reverse transmission unit is shifted to the reverse transmission state, the forward driving force output from the planetary transmission unit is driven backward by the reverse transmission unit. It is converted into force and transmitted to the traveling device. In this case, when the hydrostatic continuously variable transmission is controlled to shift, the reverse driving force transmitted to the travel device is shifted steplessly.

  According to the configuration of the first aspect of the invention, the low speed transmission clutch is provided across the low speed side transmission gear and the counter shaft, the high speed transmission clutch is provided across the high speed side transmission gear and the counter shaft, and the reverse transmission clutch is output with the reverse transmission gear. Since it is provided over the shaft, the low-speed transmission clutch, the high-speed transmission clutch, and the reverse transmission clutch are distributed and mounted on the counter shaft and the output shaft, and can be easily incorporated into the traveling transmission portion.

  Therefore, it is easy to make the traveling device transmit the forward driving force in a wide speed range over a wide range of speeds in two stages, and to easily display the traveling speed adapted to the work and the traveling location. It is possible to transmit the reverse drive force to the traveling device by simply providing the reverse transmission unit without providing the hydraulic continuously variable transmission part with the function of displaying the reverse drive force, and to transmit the reverse drive. It can be carried out in an efficient state and at a low cost. Further, the low-speed transmission clutch, the high-speed transmission clutch, and the reverse transmission clutch can be easily incorporated into the traveling transmission portion, and can be obtained at low cost from this aspect.

  The second aspect of the invention relates to a reduction transmission ratio when the low-speed output gear is transmitted from the low-speed output gear to the output shaft via the reverse transmission gear and the reverse transmission clutch. It is set to be smaller than a reduction transmission ratio when it is transmitted to the output shaft through the low speed transmission clutch, the counter shaft, the counter gear, and the output shaft gear.

  According to the configuration of the second aspect of the invention, the output when the reverse transmission clutch is operated to be engaged and the output shaft is driven to the reverse side, and the output shaft is driven to change speed as the hydrostatic continuously variable transmission is changed. The shift range of the output shaft is changed when the output shaft is driven to shift in accordance with the shift of the hydrostatic continuously variable transmission section when the output shaft is driven forward by the operation of the low speed transmission clutch being engaged. Be bigger than the range.

  Therefore, the traveling device is driven to shift backward in a shift range wider than the shifting range when the traveling device is driven to the forward side when the low-speed transmission clutch is engaged, and the reverse traveling adapted to the work and the traveling location is performed. Easy to show speed.

It is a side view which shows the whole tractor. It is a skeleton figure which shows a transmission device. It is explanatory drawing which shows the relationship between the shifting state of a hydrostatic continuously variable transmission part, and the traveling speed of a self-propelled vehicle. It is explanatory drawing which shows the relationship between the shifting state of a sub-transmission part, the operation state of a low-speed transmission clutch, the operation state of a high-speed transmission clutch, the operation state of a reverse transmission clutch, and the traveling direction, speed range, and speed mode of a self-propelled vehicle. It is a block diagram which shows a speed change operation apparatus. It is a skeleton figure which shows the transmission apparatus part for driving | running | working provided with another implementation structure. It is a front view which shows the gear arrangement | positioning of the speed range setting part and reverse transmission part in the transmission apparatus part for driving | running | working provided with another implementation structure. It is explanatory drawing which shows the relationship between the speed change state of the hydrostatic continuously variable transmission part in the transmission apparatus part for driving | running | working provided with another implementation structure, and the traveling speed of a self-propelled vehicle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing the entire tractor. As shown in this figure, the tractor is composed of a self-propelled vehicle that is self-propelled by a pair of left and right steering operations and front wheels 1, 1 that can be driven and a pair of left and right driveable rear wheels 2, 2. A transmission case equipped with an engine 3 provided at the front of the vehicle body, a riding-type driving unit equipped with a driver seat 4 provided at the rear of the vehicle, and a rear part of the body frame 5 of the self-propelled vehicle A link mechanism 6 having a pair of left and right lift arms 6a, 6a attached to be freely swingable up and down, and a power take-out shaft 7 protruding rearward from the transmission case toward the vehicle body.

  This tractor is configured so that a rotary tiller is connected to the rear part of the vehicle body via a link mechanism 6 so as to be movable up and down, and the driving force output from the engine 3 is transmitted from the power take-out shaft 7 to the rotary tiller. Various working devices are connected to the rear portion of the vehicle body so as to be movable up and down and can be driven, such as a riding type tiller.

  FIG. 2 is provided in a self-propelled vehicle so that the driving force output from the engine 3 is transmitted to a pair of left and right front wheels 1 and 1 and a pair of left and right rear wheels 2 and 2 as a traveling device and a power take-out shaft 7. FIG. 6 is a skeleton diagram showing a transmission device D. As shown in this figure, the transmission device D transmits the driving force from the output shaft 3a of the engine 3 from the output shaft 10a of the main clutch mechanism 10 provided at the rear of the engine 3 to the hydrostatic continuously variable transmission unit 11 and A pair of left and right rear wheels are input to the planetary transmission unit 30 and transmitted from the planetary transmission unit 30 to the traveling transmission unit S and transmitted from the traveling transmission unit S to the rear wheel differential mechanism 12 and the front wheel differential mechanism 13. 2 and 2 and a pair of left and right front wheels 1 and 1 for driving transmission D1 and the driving force from the output shaft 3a of the engine 3 from the output shaft 10a of the main clutch mechanism 10 to the rotary transmission shaft 25 and A work transmission device D that is input to the work clutch 14 via the rotation transmission shaft 14 a and is transmitted from the work clutch 14 to the work transmission unit 15 and transmitted from the work transmission unit 15 to the power take-out shaft 7. It is equipped with a door.

  The work transmission unit 15 can be shifted to a plurality of shift states by a plurality of shift gears, and the drive force input and shifted from the work clutch 14 is transferred from the output shaft 15 a to the power take-out shaft 7 via the work transmission shaft 19. Be transmitted.

The traveling transmission device D1 will be described.
As shown in FIG. 2, the traveling transmission device D1 includes a hydrostatic continuously variable transmission 11 having an input shaft 11a linked to an output shaft 10a of the main clutch mechanism 10 via an input gear mechanism 20, The planetary transmission unit 30 is connected to the output shaft 10a of the main clutch mechanism 10 via the planetary interlocking mechanism 24 via the planetary interlocking mechanism 24, and the planetary transmission unit 30 inputs the speed range setting unit 40 or the reverse transmission unit 50. When input to either the speed range setting unit 40 or the reverse transmission unit 50, a traveling transmission unit S that transmits power from the output shaft 43 to the rear wheel differential mechanism 12 and the front wheel differential mechanism 13 via the auxiliary transmission unit 60 is provided. Configured.

  An input gear mechanism 20 that interlocks the output shaft 10a of the main clutch mechanism 10 and the input shaft 11a of the hydrostatic continuously variable transmission unit 11 includes an output shaft gear 21 that is rotatably provided integrally with the output shaft 10a of the main clutch mechanism 10. The input shaft gear 22 is provided so as to be integrally rotatable with the input shaft 11a of the hydrostatic continuously variable transmission 11 while being engaged with the output shaft gear 21.

  The planetary interlocking mechanism 24 that interlocks the output shaft 10a of the main clutch mechanism 10 and the input side ring gear 33a of the planetary transmission unit 30 includes a rotation transmission shaft 25 that is integrally rotatable with the output shaft 10a of the main clutch mechanism 10, and The transmission gear 26 is provided so as to be rotatable integrally with the rotary transmission shaft 25, and the input gear 27 is provided so as to be rotatable integrally with the input side ring gear 33a in a state of meshing with the transmission gear 26. The input gear 27 is supported by the motor shaft 11b of the hydrostatic continuously variable transmission 11 together with the input side ring gear 33a so as to be relatively rotatable.

  The hydrostatic continuously variable transmission unit 11 includes a hydraulic pump 11P having an input shaft 11a as a pump shaft, and a hydraulic motor 11M connected to the hydraulic pump 11P via a drive circuit. The hydraulic pump 11P is constituted by an axial plunger type variable displacement type hydraulic pump, and the hydraulic motor 11M is constituted by an axial plunger type hydraulic motor.

  Accordingly, the hydrostatic continuously variable transmission unit 11 drives the hydraulic pump 11P by the driving force input from the engine 3 to the input shaft 11a via the input gear mechanism 20 and the main clutch mechanism 10, and the hydraulic pump 11P supplies the hydraulic pressure to the hydraulic pressure. The motor 11M is supplied to drive the hydraulic motor 11M to output from the motor shaft 11b. The hydrostatic continuously variable transmission unit 11 is shifted between a forward rotation state, a neutral state, and a reverse rotation state by changing the swash plate angle of the hydraulic pump 11P, and is shifted to the forward rotation state. Then, the driving force in the forward rotation direction is output from the motor shaft 11b, and when the gear is shifted to the neutral state, the output from the motor shaft 11b is stopped, and when the gear is shifted to the reverse rotation gear shift state, the motor shaft 11b is reversed. Outputs the driving force in the rotation direction. The hydrostatic continuously variable transmission 11 is operated from the motor shaft 11b by changing the swash plate angle of the hydraulic pump 11P regardless of whether the transmission is in the forward rotation or reverse rotation. Change the output speed steplessly.

  The planetary transmission unit 30 includes an input-side sun gear 34 a that is linked to the motor shaft 11 b of the hydrostatic continuously variable transmission unit 11 so as to be integrally rotatable, and an input-side ring gear that is linked to the rotary transmission shaft 25 via the planetary linkage mechanism 24. An input-side planetary gear mechanism 30A having 33a and an output-side planetary gear mechanism 30B located on the lower side in the transmission direction with respect to the input-side planetary gear mechanism 30A are configured. The input-side carrier 36a that supports the input-side planetary gear 35a of the input-side planetary gear mechanism 30A and the output-side carrier 36b that supports the output-side planetary gear 35b of the output-side planetary gear mechanism 30B are configured as an integral carrier. Yes. That is, the planetary transmission unit 30 includes a pair of planetary gear mechanisms of the input planetary gear mechanism 30A and the output planetary gear mechanism 30B, and the input planetary gear 35a and the output planetary gear mechanism 30B constituting the input planetary gear mechanism 30A. Is constituted by a compound planetary gear mechanism comprising a gear interlocking mechanism 37 for interlocking the output side planetary gear 35b constituting the. The gear interlocking mechanism 37 is integrally formed with the input side planetary gear 35a by being integrally formed with the input side planetary gear 35a, and the output side planetary gear 35b is integrally formed with the output side planetary gear 35b. The planetary gear 35b and a gear 37b having a structure having the same outer diameter are meshed and interlocked with each other. The input side planetary gear 35a is formed separately from the input side planetary gear 35a and is integrally connected to the input side planetary gear 35a by a connecting shaft or the like, and the output side planetary gear 35b is formed separately from the output side planetary gear 35a. The gear interlocking mechanism 37 may be configured by meshing and interlocking with a gear 35b that is connected to the gear 35b by a connecting shaft or the like so as to be integrally rotatable.

  The planetary transmission unit 30 is integrally rotatable with the output-side sun gear 34b via the output shaft 32a so as to be integrally rotated, and the output-side ring gear 33b is integrally rotatable with the cylindrical shaft-shaped output shaft 31a. An interlocked low-speed output gear 31 is provided.

  The planetary transmission unit 30 inputs the driving force output from the engine 3 to the input side ring gear 33a via the main clutch mechanism 10 and the planetary interlocking mechanism 24, and the hydrostatic continuously variable transmission unit 11 outputs from the motor shaft 11b. Force is input to the input-side sun gear 34a, and the driving force input from the engine 3 and the driving force input from the hydrostatic continuously variable transmission unit 11 are combined by the input-side planetary mechanism 30A and the output-side planetary mechanism 30B. Force is output from the low speed side output gear 31 and the high speed side output gear 32. The planetary transmission unit 30 does not synthesize the reverse driving force and does not synthesize the forward driving force regardless of whether the hydrostatic continuously variable transmission unit 11 is shifted to either the forward rotational speed state or the reverse rotational speed state. Are combined and output from the low speed side output gear 31 and the high speed side output gear 32.

  The traveling transmission unit S has a low speed side transmission gear 41 meshed with the low speed side output gear 31 of the planetary transmission unit 30 and a high speed side transmission gear 42 meshed with the high speed side output gear 32 of the planetary transmission unit 30. The input shaft 60 a is linked to the range setting unit 40, the reverse transmission unit 50 having the reverse transmission gear 51 meshed with the low-speed output gear 31 of the planetary transmission unit 30, and the output shaft 43 of the speed range setting unit 40. The auxiliary transmission unit 60 is provided.

  The speed range setting unit 40 includes the low-speed transmission gear 41 and the high-speed transmission gear 42, and a cylindrical counter shaft 44 that supports the low-speed transmission gear 41 and the high-speed transmission gear 42 in a relatively rotatable manner. The low-speed transmission clutch 45 provided across the low-speed transmission gear 41 and the counter shaft 44, the high-speed transmission clutch 46 provided across the high-speed transmission gear 42 and the counter shaft 44, and the rear end side of the counter shaft 44 are integrated. The counter gear 47 is provided so as to be rotatable, and the output shaft gear 48 is provided so as to be integrally rotatable with the output shaft 43 while being engaged with the counter gear 47.

  The low-speed transmission clutch 45 and the high-speed transmission clutch 46 include a clutch body 49 provided on the counter shaft 44 so as to be integrally rotatable and slidable, and are configured as meshing clutches. In the low-speed transmission clutch 45, the clutch body 49 is shifted along the counter shaft 44 to the side where the low-speed side transmission gear 41 is located, and the clutch pawl 45b provided on the clutch body 49 and the low-speed side transmission gear 41 side. The clutch pawl 45a provided in the portion engages with the clutch pawl 45a to engage, and the low-speed transmission gear 41 is connected to the counter shaft 44 so as to be integrally rotatable.

  The low speed transmission clutch 45 is shifted along the counter shaft 44 toward the side where the clutch body 49 is separated from the low speed side transmission gear 41, and the clutch pawl 45 b of the clutch body 49 and the clutch pawl 45 a of the low speed side transmission gear 41 are By disengagement, the cut state is established, and the relative rotation of the low speed side transmission gear 41 with respect to the counter shaft 44 is enabled.

  In the high-speed transmission clutch 46, the clutch body 49 is shifted along the counter shaft 44 to the side where the high-speed side transmission gear 42 is located, and the clutch pawl 46b provided on the clutch body 49 and the high-speed side transmission gear 42 side. The clutch claw 46a provided in the portion engages with the clutch claw 46a to enter the engaged state, and the high speed side transmission gear 42 is connected to the counter shaft 44 so as to be integrally rotatable.

  The high-speed transmission clutch 46 is shifted along the counter shaft 44 toward the side where the clutch body 49 is separated from the high-speed side transmission gear 42, and the clutch pawl 46b of the clutch body 49 and the clutch pawl 46a of the high-speed side transmission gear 42 By disengaging the gear, the cut state is established, and the high speed side transmission gear 42 can be rotated relative to the counter shaft 44.

  Therefore, the speed range setting unit 40 is operated so that the low-speed transmission clutch 45 is switched to the engaged state and the high-speed transmission clutch 46 is switched to the disengaged state, so that the planetary transmission unit 30 outputs from the low-speed output gear 31. Driving force is transmitted to the output shaft 43 through the low speed side transmission gear 41, the low speed transmission clutch 45, the counter shaft 44, the counter gear 47, and the output shaft gear 48, and the forward driving force is transmitted from the output shaft 43 to the auxiliary transmission section 60. The first speed range is set so that the power is transmitted with the driving force.

  The speed range setting unit 40 is used for forward movement output from the high-speed output gear 32 by the planetary transmission unit 30 when the high-speed transmission clutch 46 is switched to the engaged state and the low-speed transmission clutch 45 is switched to the disconnected state. The driving force is transmitted to the output shaft 43 through the high speed side transmission gear 42, the high speed transmission clutch 46, the counter shaft 44, the counter gear 47, and the output shaft gear 48, and the forward driving force is transmitted from the output shaft 43 to the sub transmission 60. The 2nd speed range setting state is entered so that transmission can be continued.

  When the low speed transmission clutch 45 and the high speed transmission clutch 46 are switched to the disengaged state, the speed range setting unit 40 is in a neutral state so as to stop transmission from the planetary transmission unit 30 to the auxiliary transmission unit 60.

  The reverse transmission unit 50 includes the reverse transmission gear 51, and the reverse transmission clutch 52 provided across the output shaft 43 of the speed range setting unit 40 and the reverse transmission gear 51 that supports the reverse transmission gear 51 in a relatively rotatable manner. It is configured with.

  The reverse transmission clutch 52 includes a clutch body 53 that is provided on the output shaft 43 so as to be integrally rotatable and slidable, and is configured as a meshing clutch. The reverse transmission clutch 52 is engaged with a clutch pawl 52 b provided on the clutch body 53 and a clutch pawl 52 a provided on the side of the reverse transmission gear 51 when the clutch body 53 is shifted along the output shaft 43. By fitting, the reverse transmission gear 51 is connected to the output shaft 43 so as to be integrally rotatable. The reverse transmission clutch 52 is turned off when the clutch body 53 is shifted along the output shaft 43 and the clutch pawl 52b of the clutch body 53 and the clutch pawl 52a of the reverse transmission gear 51 are disengaged. The reverse transmission gear 51 can be rotated relative to the output shaft 43.

  When the reverse transmission clutch 52 is switched to the engaged state, the reverse transmission unit 50 causes the reverse transmission gear 41 and the reverse transmission clutch 52 to apply the forward drive force output from the low-speed output gear 31 by the planetary transmission unit 30. The drive force is converted into the reverse drive force and transmitted to the output shaft 43, and the reverse drive force is transmitted from the output shaft 43 to the auxiliary transmission unit 60.

  When the reverse transmission clutch 52 is switched to the disengaged state, the reverse transmission unit 50 is in a neutral state so as to stop transmission from the planetary transmission unit 30 to the auxiliary transmission unit 60.

  The auxiliary transmission 60 includes the input shaft 60a, an output shaft 61 whose rear end is connected to the input gear of the rear wheel differential mechanism 12, and a low-speed transmission mechanism provided across the output shaft 61 and the input shaft 60a. 62 and a high-speed transmission mechanism 63. The output shaft 61 is interlocked with the input gear of the front wheel differential mechanism 13 via the gear interlocking mechanism 16, the front wheel output shaft 17 and the rotating shaft 18. The low speed transmission mechanism 62 includes a friction type low speed clutch 64 mounted on the input shaft 60a. The high speed transmission mechanism 63 includes a friction type high speed clutch 65 mounted on the input shaft 60a.

  When the low speed clutch 64 is switched to the engaged state and the high speed clutch 65 is switched to the disengaged state, the sub-transmission unit 60 is driven by the forward driving force transmitted from the speed range setting unit 40 to the input shaft 60a or The reverse driving force transmitted from the reverse transmission unit 50 to the input shaft 60 a is transmitted to the output shaft 61 through the low speed transmission mechanism 62 and transmitted from the output shaft 61 to the rear wheel differential mechanism 12 and the front wheel differential mechanism 13. To slow down.

  When the high speed clutch 65 is switched to the engaged state and the low speed clutch 64 is switched to the disengaged state, the sub-transmission unit 60 is driven by the forward driving force transmitted from the speed range setting unit 40 to the input shaft 60a or The reverse drive force transmitted from the reverse transmission unit 50 to the input shaft 60a is transmitted to the output shaft 61 through the high speed transmission mechanism 63 and transmitted from the output shaft 61 to the rear wheel differential mechanism 12 and the front wheel differential mechanism 13. To be in a high speed state.

  FIG. 3 is an explanatory diagram showing the relationship between the shift state of the hydrostatic continuously variable transmission unit 11 and the traveling speed (vehicle speed) of the self-propelled vehicle when the engine 3 is accelerator-set so as to output a driving force at a constant speed. It is. The horizontal axis in FIG. 3 indicates the speed change state of the hydrostatic continuously variable transmission unit 11, the horizontal axis “N” indicates the neutral position of the hydrostatic continuously variable transmission unit 11, and the horizontal axis “+ max” indicates “+ max”. The maximum speed position of the hydrostatic continuously variable transmission unit 11 in the forward rotational speed change state is shown, and the horizontal axis “−max” indicates the maximum speed position of the hydrostatic continuously variable transmission unit 11 in the reverse rotational speed change state. Show. The vertical axis in FIG. 3 represents the vehicle speed, “0” on the vertical axis represents the vehicle speed zero, the portion above “0” on the vertical axis represents the forward vehicle speed, and the vertical axis represents “0”. The lower part shows the reverse vehicle speed.

  A solid line FL1 shown in FIG. 3 indicates a change in the vehicle speed in the first speed range in the low speed mode when the self-propelled vehicle travels forward, and a solid line FL2 shown in FIG. 3 indicates the low speed mode when the self-propelled vehicle travels forward. The vehicle speed change in the 2nd speed range is shown. A solid line FH1 shown in FIG. 3 indicates a change in the vehicle speed in the first speed range in the high speed mode when the self-propelled vehicle is driven forward, and a solid line FH2 shown in FIG. 3 is a high speed mode when the self-propelled vehicle is driven forward. The vehicle speed change in the 2nd speed range is shown. A solid line RL shown in FIG. 3 indicates a change in vehicle speed in the low speed mode when the self-propelled vehicle is driven backward, and a solid line RH shown in FIG. 3 indicates a change in vehicle speed in the high speed mode when the self-propelled vehicle is driven backward. Show.

  FIG. 4 shows the shift state of the sub-transmission unit 60, the operation state of the low-speed transmission clutch 45, the operation state of the high-speed transmission clutch 46, the operation state of the reverse transmission clutch 52, the traveling direction of the self-propelled vehicle, the speed range, and the speed mode. It is explanatory drawing which shows a relationship. “L” shown in FIG. 4 indicates the low speed state of the auxiliary transmission unit 60, and “H” shown in FIG. 4 indicates the high speed state of the auxiliary transmission unit 60. “ON” shown in FIG. 4 indicates the engaged state of the low speed transmission clutch 45, the high speed transmission clutch 46, and the reverse transmission clutch 52, and “OFF” shown in FIG. 4 indicates the low speed transmission clutch 45, the high speed transmission clutch 46, and the reverse transmission. The disengagement state of the clutch 52 is shown.

  As shown in FIG. 4, the low speed mode is set when the sub transmission 60 is shifted to the low speed state, and the high speed mode is set when the sub transmission 60 is shifted to the high speed. When the reverse transmission clutch 52 is switched to the disengaged state, the reverse transmission unit 50 is switched to the neutral state to enter the forward transmission state. When the reverse transmission clutch 52 is switched to the engaged state, the reverse transmission unit 50 is switched to the reverse transmission state to enter the reverse transmission state.

  As shown in FIGS. 3 and 4, the low-speed transmission clutch 45 is engaged when the sub-transmission unit 60 is maintained in the low-speed state “L” and the reverse transmission clutch 52 is maintained in the disengaged state “off”. And the high-speed transmission clutch 46 is controlled to be switched to the disconnected state “OFF”, and the hydrostatic continuously variable transmission unit 11 is rotated forward from the highest speed position “−max” in the reverse rotation speed-shifted state. By performing shift control toward the highest speed position “+ max” in the shift state, the forward vehicle speed is increased steplessly from zero “0” in the first speed range (FL1) in the low speed mode. When the hydrostatic continuously variable transmission 11 reaches the maximum speed position “+ max” in the forward rotation speed change state, the forward vehicle speed becomes the intermediate speed “f1” in the low speed mode. When the hydrostatic continuously variable transmission unit 11 reaches the maximum speed position “+ max” in the forward rotation speed change state, a switching point “T1” for switching between the first speed range and the second speed range in the low speed mode is obtained. Simultaneously with the switching point “T1”, the low-speed transmission clutch 45 is controlled to be switched to the “off” state, and the high-speed transmission clutch 46 is controlled to be switched to the “on” state. Thereafter, the hydrostatic continuously variable transmission unit 11 is forward-shifted while the low-speed transmission clutch 45 is controlled to be switched to the disconnected state “OFF” and the high-speed transmission clutch 46 is controlled to be switched to the “ON” state. The speed is controlled from the highest speed position “+ max” to the highest speed position “−max” in the reverse rotation speed change state, so that the forward vehicle speed is continuously variable from “f1” to the second speed range (FL2) in the low speed mode. The speed will increase. When the hydrostatic continuously variable transmission 11 reaches the maximum speed position “−max” in the reverse rotation speed change state, the forward vehicle speed becomes the maximum speed “f2” in the low speed mode.

  In a state where the sub-transmission unit 60 is maintained in the high speed state “H” and the reverse transmission clutch 52 is maintained in the disengaged state “disengaged”, the low speed transmission clutch 45 remains switched to the engaged state “on”, and While the high-speed transmission clutch 46 is controlled to be switched to the disengaged state “disengaged”, the hydrostatic continuously variable transmission unit 11 changes from the highest speed position “−max” in the reverse rotation gear shift state to the highest speed position “+ max” in the forward rotation gear shift state. The forward vehicle speed is increased steplessly from zero “0” in the first speed range (FH1) in the high speed mode. When the hydrostatic continuously variable transmission 11 reaches the maximum speed position “+ max” in the forward rotation speed change state, the forward vehicle speed becomes the intermediate speed “f3” in the high speed mode. When the hydrostatic continuously variable transmission unit 11 reaches the maximum speed position “+ max” in the forward rotation speed change state, the switching point “T2” for switching between the first speed range and the second speed range in the high speed mode is obtained. Simultaneously with the switching point “T2”, the low-speed transmission clutch 45 is controlled to be switched to the “off” state, and the high-speed transmission clutch 46 is switched to the “on” state. Thereafter, the hydrostatic continuously variable transmission unit 11 is forward-shifted while the low-speed transmission clutch 45 is controlled to be switched to the disconnected state “OFF” and the high-speed transmission clutch 46 is controlled to be switched to the “ON” state. The forward vehicle speed is continuously variable from “f3” to the second speed range (FH2) from “f3” by shifting control from the highest speed position “+ max” to the highest speed position “−max” in the reverse rotation speed change state. The speed will increase. When the hydrostatic continuously variable transmission 11 reaches the maximum speed position “−max” in the reverse rotation speed change state, the forward vehicle speed becomes the maximum speed “f4” in the high speed mode.

  In a state where the sub-transmission unit 60 is maintained in the low speed state “L” and the reverse transmission clutch 45 is maintained in the engaged state “on”, the low speed transmission clutch 45 remains controlled to be switched to the disengaged state “off”, and While the high-speed transmission clutch 46 is controlled to be switched to the disengaged state “disengaged”, the hydrostatic continuously variable transmission unit 11 changes from the highest speed position “−max” in the reverse rotation gear shift state to the highest speed position “+ max” in the forward rotation gear shift state. As a result, the reverse vehicle speed is continuously increased from zero “0” in the low speed mode (RL). When the hydrostatic continuously variable transmission 11 reaches the maximum speed position “+ max” in the forward rotation speed change state, the reverse vehicle speed becomes the maximum speed “r1” in the low speed mode.

  In a state where the sub-transmission unit 60 is maintained in the high speed state “H” and the reverse transmission clutch 45 is maintained in the engaged state “on”, the low speed transmission clutch 45 remains controlled to be switched to the disconnected state “off”, and While the high-speed transmission clutch 46 is controlled to be switched to the disengaged state “disengaged”, the hydrostatic continuously variable transmission unit 11 changes from the highest speed position “−max” in the reverse rotation gear shift state to the highest speed position “+ max” in the forward rotation gear shift state. As a result, the reverse vehicle speed is continuously increased from zero “0” in the high speed mode (RH). When the hydrostatic continuously variable transmission 11 reaches the maximum speed position “+ max” in the forward rotation speed change state, the reverse vehicle speed becomes the maximum speed “r2” in the high speed mode. Note that the rate of change (inclination) of the low-speed mode 1-speed range FL1 during forward travel and the low-speed mode RL during reverse travel in FIG. 3 are the same, and the high-speed 1-speed range FH1 during forward travel and the reverse-speed travel The transmission ratio transmitted from the low-speed output gear 31 to the output shaft 61 via the low-speed transmission clutch 45 and the reverse transmission from the low-speed output gear 31 so that the rate of change (inclination) of the high-speed mode RH is the same. The transmission ratio transmitted to the output shaft 61 via the part 50 is set to be the same.

  FIG. 5 is a block diagram showing a speed change operating device 70 that changes the speed of the traveling transmission device D1. As shown in this figure, the speed change operating device 70 is a low speed transmission of the speed change operation unit 71 and the speed range setting unit 40 provided in the hydrostatic continuously variable transmission 11 to change the swash plate angle of the hydraulic pump 11P. A switching operation unit (not shown) for the clutch 45 and the high-speed transmission clutch 46, a switching operation unit (illustrated) for the reverse transmission clutch 52, and a switching operation unit for the high-speed clutch 65 and the low-speed clutch 64 of the auxiliary transmission unit 60. A control device 72, a transmission lever 73, an engine rotation sensor 74 that detects the output speed of the engine 3, a forward / reverse lever 75, and a sub-transmission lever 76 are provided. .

  The shift lever 73 is linked to the control device 72 via a shift detection sensor 73 a linked to the shift lever 73. The shift detection sensor 73 a is configured by a rotary potentiometer in which a rotation operation unit is linked to the shift lever 73, detects the operation position of the shift lever 73, and outputs the detection result to the control device 72.

  The forward / reverse lever 75 is linked to the control device 72 via a forward / backward detection sensor 75 a linked to the forward / reverse lever 75. The forward / reverse detection sensor 75 a is configured by a rotary potentiometer whose rotational operation unit is linked to the forward / reverse lever 75, detects the operation position of the forward / reverse lever 75, and outputs the detection result to the control device 72.

  The sub transmission lever 76 is linked to the control device 72 via a sub shift detection sensor 76 a linked to the sub transmission lever 76. The sub-shift detection sensor 76 a is configured by a rotary potentiometer in which a rotation operation unit is linked to the sub-shift lever 76, detects the operation position of the sub-shift lever 76, and outputs the detection result to the control device 72.

  The control device 72 is configured using a microcomputer, and includes a main transmission control means 77, a forward / reverse switching means 78, and an auxiliary transmission control means 79.

  The main shift control means 77 detects the output speed of the engine 3 when the engine 3 is accelerator-set based on information detected by the engine rotation sensor 74, and based on the detection information detected by the shift detection sensor 73a. The operation position is determined, and the detected output speed of the engine 3 and the determined operation position of the shift lever 73 and the command from the forward / reverse detection sensor 75a correspond to the operation positions of the shift lever 73 and the forward / reverse lever 75. The hydrostatic continuously variable transmission 11 is automatically shift-controlled so that a predetermined forward vehicle speed or reverse vehicle speed appears, and the low-speed transmission clutch 45 and the high-speed transmission clutch 46 are automatically switched.

  When the forward / reverse lever 75 is operated to the forward position “forward”, the forward / reverse switching means 78 automatically switches the reverse transmission clutch 62 to the disconnected state “off” based on information detected by the forward / reverse detection sensor 75a. When the forward / reverse lever 75 is operated to the reverse position “rear”, the reverse transmission clutch 52 is automatically switched to the engaged state “ON” based on the detection information from the forward / reverse detection sensor 75a.

  When the sub transmission lever 76 is operated to the high speed position “high”, the sub transmission control means 79 automatically switches the high speed clutch 65 to the engaged state based on the detection information by the sub transmission detection sensor 76a, and operates the low speed control. The clutch 64 is automatically switched to the disengaged state, and the sub-transmission unit 60 is controlled to shift to the high speed state “H”. When the sub-shift lever 76 is operated to the low speed position “low”, the sub-shift control means 79 automatically switches the high-speed clutch 65 to the disengaged state based on the detection information from the sub-shift detection sensor 76a. The sub-transmission unit 60 is controlled to shift to the low speed state “L” by automatically switching the clutch 64 to the engaged state.

[Another embodiment]
FIG. 6 is a skeleton diagram showing a traveling transmission device D1 having another embodiment structure. As shown in this figure, the traveling transmission device D1 having another implementation structure has a different configuration from the transmission device D1 of the above-described embodiment in terms of the speed range setting unit 40 and the reverse transmission unit 50. In other respects, the transmission device D1 has the same configuration as that of the above-described embodiment.

  In the traveling transmission device D1 having another embodiment structure, the low-speed transmission clutch 45 and the high-speed transmission clutch 46 constituting the speed range setting unit 40 and the reverse transmission clutch 52 constituting the reverse transmission unit 50 are multi-plate type frictions. It is composed of a clutch.

  Accordingly, the on / off state of the low-speed transmission clutch 45, the high-speed transmission clutch 46, and the reverse transmission clutch 52 can be switched quickly and smoothly, and the first speed range and the second speed range in the low speed mode and the high speed mode are switched. It is possible to continuously change the vehicle speed at the switching points “T1” and “T2” so as not to be interrupted, and to smoothly perform forward / reverse switching.

  FIG. 7 is a front view showing a gear arrangement of the speed range setting unit 40 and the reverse transmission unit 50 in the traveling transmission unit D1 having another embodiment structure. As shown in FIG. 6 and FIG. 6, in the traveling transmission device D1 having another implementation structure, the driving force output by the planetary transmission unit 30 is transmitted from the low-speed output gear 31 to the reverse transmission gear 51 and the reverse transmission clutch. The driving force output by the planetary transmission unit 30 from the low-speed output gear 31 to the low-speed transmission gear 41, the low-speed transmission clutch 45, and the counter shaft 44, the reduction gear ratio is set to be smaller than that when the gear is decelerated and transmitted to the output shaft 43 via the counter gear 47 and the output shaft gear 48.

  Accordingly, as shown in FIG. 8, the speed range of the vehicle speed in the low speed mode (RL) during reverse travel can be made larger than the speed range of the vehicle speed in the first speed range (FL1) in the low speed mode during forward travel. That is, the maximum vehicle speed r1 that can appear when shifting in the low speed mode (RL) during reverse travel is higher than the maximum vehicle speed f1 that can appear when shifting in the first speed range (FL1) of the low speed mode during forward travel. Become. The shift range of the vehicle speed in the high speed mode (RH) during reverse travel can be made larger than the shift range of the vehicle speed in the first speed range (FH1) in the high speed mode during forward travel. That is, the maximum vehicle speed r2 that can appear when shifting in the high speed mode (RH) during reverse travel is higher than the maximum vehicle speed f3 that appears when shifting in the first speed range (FH1) of the high speed mode during forward travel. become.

[Another Example]
(1) Although the example in which the auxiliary transmission unit 60 is provided has been described in the above-described embodiment, the auxiliary transmission unit 60 may be provided without being provided.

  (2) In the above-described embodiment, an example in which the planetary transmission unit 30 is configured by a compound planetary gear mechanism has been described, but it may be configured by a normal planetary gear mechanism in which gear mechanisms are arranged in multiple stages.

  (3) In the above-described embodiment, an example in which the front wheels 1 and the rear wheels 2 are provided as travel devices has been described, but a crawler travel device may be provided instead of the wheels.

  (4) In the above-described embodiment, the low-speed transmission clutch 45, the high-speed transmission clutch 46, and the reverse transmission clutch 52 are constituted by meshing clutches, and the low-speed transmission clutch 45, the high-speed transmission clutch 46, and the reverse transmission clutch 52 are provided. Although the example which comprised the multi-plate type friction clutch was shown, any one or more of the forward transmission clutch 45, the high speed transmission clutch 46, and the reverse transmission clutch 52 are comprised by a meshing-type clutch, and other clutches are used. A configuration of a multi-plate friction clutch may be employed.

  (5) The transmission structure shown in FIG. 2 may be configured to have the gear ratio shown in FIG. 8, or the transmission structure shown in FIG. 6 may be configured to have the gear ratio shown in FIG. May be.

  The present invention relates to a transmission device provided in a tractor in which a working device such as a mowing device is connected between front and rear wheels of the vehicle body or a front portion of the vehicle body, in addition to a transmission device provided in a tractor in which a work device is connected to the rear portion of the vehicle body. Is also available.

DESCRIPTION OF SYMBOLS 1, 2 Traveling apparatus 3 Engine 11 Hydrostatic continuously variable transmission part 30 Planetary transmission part 31 Low speed side output gear 32 High speed side output gear 40 Speed range setting part 41 Low speed side transmission gear 42 High speed side transmission gear 43 Output shaft 44 Counter shaft 45 Low-speed transmission clutch 46 High-speed transmission clutch 47 Counter gear 48 Output shaft gear 50 Reverse transmission portion 51 Reverse transmission gear 52 Reverse transmission clutch S Traveling transmission portion

Claims (2)

A hydrostatic continuously variable transmission unit that inputs driving force from the engine, a planetary transmission unit that combines and outputs the driving force output from the hydrostatic continuously variable transmission unit and the driving force from the engine, and the planetary transmission A tractor transmission device comprising a traveling transmission unit for transmitting the output of the unit to the traveling device,
In the state where the planetary transmission unit is shifted to either the forward rotational speed state where the hydrostatic continuously variable transmission portion outputs the driving force in the forward rotational direction or the reverse rotational speed state where the driving force in the reverse rotational direction is output. Is configured to output the driving force for forward movement,
The driving power output from the planetary power transmission unit is divided into a plurality of speed ranges, and the multi-speed transmission state and the power output as the driving power are stopped. A speed range setting unit that can be shifted in a neutral state, a reverse transmission state in which the forward driving force output from the planetary transmission unit is converted into a reverse driving force, and a neutral state in which transmission is stopped. There is a reverse transmission that can be switched to
The planetary transmission unit is provided with a low speed side output gear and a high speed side output gear,
A low-speed side transmission gear that is supported by the counter shaft so as to be relatively rotatable while meshed with the low-speed side output gear, and a high-speed side that is supported by the counter shaft while being meshed with the high-speed side output gear. A transmission gear, a counter gear that is rotatably supported by the counter shaft, an output shaft gear that is rotatably supported by the output shaft while meshing with the counter gear, and the low-speed transmission gear are used as the counter shaft. A low-speed transmission clutch that can be switched between an engaged state in which the low-speed side transmission gear is connected to be freely rotatable and a cut-off state that allows relative rotation of the low-speed side transmission gear with respect to the counter shaft, A high-speed transmission clutch that can be switched between a connected engagement state and a cut-off state that enables relative rotation of the high-speed side transmission gear with respect to the counter shaft; Configure the Nji setting section,
A reverse transmission gear that is rotatably supported by the output shaft in mesh with the low-speed side output gear, a closed state in which the reverse transmission gear is connected to the output shaft so as to be integrally rotatable, and the reverse transmission gear. A transmission device for a tractor comprising a reverse transmission clutch that enables relative rotation with respect to an output shaft and constituting the reverse transmission portion.   The reduction transmission ratio when the low-speed output gear is transmitted to the output shaft via the reverse transmission gear and the reverse transmission clutch, the low-speed transmission gear, the low-speed transmission clutch, 2. The transmission device for a tractor according to claim 1, wherein the transmission device is set to be smaller than a reduction transmission ratio in the case of being transmitted to the output shaft through the counter shaft, the counter gear, and the output shaft gear.

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