JP2010088389A - Reaping-harvesting machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reaping-harvesting machine equipped with a hydraulic static transmission, constituted to be able to make the machine body traveling velocity low while avoiding decrease of driving force (torque). <P>SOLUTION: A hydraulic static transmission 7 to which the power of an engine 6 is transmitted is provided, and a hydraulic motor 7M of the hydraulic static transmission 7 is constituted to be freely speed-changeable. The power of the hydraulic motor 7M of the hydraulic static transmission 7 is divided parallelly into a travelling transmission system and a reaping transmission system to constitute to transmit the power of the travelling transmission system to the travelling device. The power of the reaping transmission system is constituted to be transmitted to a reaping part 2 and a reaping transmission 18 is equipped on a reaping transmission system. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a traveling transmission system and a structure of a cutting transmission system in a harvesting and harvesting machine such as a combine.

In the combine which is an example of a harvesting harvester, there exists a combine provided with a traveling transmission system and a cutting transmission system as disclosed in Patent Document 1.
In Patent Document 1, the power of an engine (8 of FIG. 2 of Patent Document 1) is transmitted to a hydrostatic continuously variable transmission (7 of FIG. 2 of Patent Document 1), and the output shaft of the hydrostatic continuously variable transmission The power (7b of FIG. 2 of Patent Document 1) is branched in parallel to the traveling transmission system and the cutting transmission system. The power of the travel transmission system is transmitted to the travel device (1 of FIG. 1 and FIG. 2 of Patent Document 1) through the auxiliary transmission (FIG. 2 of Patent Document 1). Is transmitted to the cutting part (FIGS. 1 and 2 in FIG. 2) via the cutting transmission (FIG. 2 in FIG. 2).

  In general, the harvesting and harvesting machine is in a state where the speed of the airframe is synchronized with the operating speed of the mowing part (the operating speed of the mowing part also becomes low when the aircraft's traveling speed becomes low, and the mowing part becomes high when the airspeed of the airframe becomes high) The state in which the operating speed is high) is preferable. Therefore, if the cutting transmission is fixed at a predetermined shift position in Patent Document 1, by operating the hydrostatic continuously variable transmission, the running speed of the fuselage and the operating speed of the cutting unit are synchronized. (The sub-transmission is generally provided with a high-speed position for traveling on the road or on the eaves, and with a low-speed position for cutting on the field. The sub-transmission is fixed at a low speed position without any operation).

JP 2004-187506 A

  In the harvesting and harvesting machine, the hydraulic pump of the hydrostatic continuously variable transmission is configured to be continuously variable on the forward side and the reverse side, and the hydraulic pump of the hydrostatic continuously variable transmission is operated to move the machine forward. In many cases, the vehicle is configured to perform a reverse operation and to control the traveling speed of the aircraft. As a result, when the crop reaches a portion where crops are violently harvested in the field, the hydraulic pump of the hydrostatic continuously variable transmission is operated to the low speed side and the traveling speed of the aircraft is controlled to a low speed.

However, operating the hydraulic pump of the hydrostatic continuously variable transmission to the low speed side reduces the discharge amount of the hydraulic pump of the hydrostatic continuously variable transmission. The force (torque) is also reduced. As a result, when the hydraulic pump of the hydrostatic continuously variable transmission is operated to the low speed side in a soft field with a large running resistance, it is considered that the driving force (torque) becomes insufficient.
It is an object of the present invention to provide a structure in which the traveling speed of an airframe can be reduced while avoiding a decrease in driving force (torque) when a hydrostatic continuously variable transmission is provided in a harvesting harvester. Yes.

[I]
(Constitution)
The first feature of the present invention resides in the following configuration in a harvesting harvester.
A hydrostatic continuously variable transmission that transmits engine power is provided, and the hydrostatic continuously variable transmission includes a hydraulic pump on the upper transmission side and a hydraulic motor on the lower transmission side. The hydraulic motor of the hydrostatic continuously variable transmission is configured to be variable. The power of the hydraulic motor of the hydrostatic continuously variable transmission is branched in parallel to the travel transmission system and the cutting transmission system, and the power of the travel transmission system is transmitted to the travel device. The power of the cutting transmission system is configured to be transmitted to the cutting unit, and the cutting transmission system is provided with a cutting transmission.

(Function)
[I] -1
Operating the hydraulic motor of the hydrostatic continuously variable transmission to the low speed side reduces the stroke of the plunger of the hydraulic motor of the hydrostatic continuously variable transmission. Even if the hydraulic oil is sufficiently supplied from the pump to the hydraulic motor, the hydraulic motor of the hydrostatic continuously variable transmission need not rotate much. Thus, when the hydraulic motor of the hydrostatic continuously variable transmission is operated to the low speed side, if the discharge amount of the hydraulic pump of the hydrostatic continuously variable transmission is secured, the hydraulic pressure of the hydrostatic continuously variable transmission Low-speed power having a sufficient driving force (torque) is transmitted from the motor to the lower transmission side.

According to the first aspect of the present invention, the engine power is transmitted to the traveling device via the hydraulic pump and hydraulic motor of the hydrostatic continuously variable transmission, and the traveling transmission system. The hydraulic motor is configured to be freely variable.
As a result, when the discharge amount of the hydraulic pump of the hydrostatic continuously variable transmission is secured, operating the hydraulic motor of the hydrostatic continuously variable transmission to the low speed side provides sufficient driving force (torque). Since the low-speed power is transmitted to the traveling device, the traveling speed of the low-speed aircraft can be obtained without running out of driving force (torque) even in a soft field with a large traveling resistance.

[I] -2
According to the first feature of the present invention, the power of the hydraulic motor of the hydrostatic continuously variable transmission is branched in parallel to the traveling transmission system and the cutting transmission system so that the power of the traveling transmission system is transmitted to the traveling apparatus. It is comprised and it is comprised so that the motive power of a cutting transmission system may be transmitted to a cutting part.
Thus, when the hydraulic motor of the hydrostatic continuously variable transmission is operated, the power shifted by the hydraulic motor of the hydrostatic continuously variable transmission is transmitted in parallel to the travel device and the cutting unit. In the same manner as above, a state in which the traveling speed of the airframe and the operating speed of the cutting unit are synchronized is obtained.

[I] -3
When the crops reach a part where crops are violently harvested in the field, it is necessary to make the running speed of the aircraft sufficiently low.
As a result, as described in the preceding paragraphs [I] -1 and 2, when the hydraulic motor of the hydrostatic continuously variable transmission is operated to the low speed side and the traveling speed of the machine is sufficiently low, The speed is also sufficiently low (the operating speed of the cutting part becomes too low), and stable cutting at the cutting part may not be possible (if the operating speed above a certain level is not secured in the cutting part) , You may not be able to perform stable mowing).

  According to the first feature of the present invention, since the cutting transmission system includes the cutting transmission, the hydraulic motor of the hydrostatic continuously variable transmission is moved to the low speed side as described in the preceding paragraphs [I] -1 and 2. If the aircraft's running speed is set to a sufficiently low speed by operating it, the operating speed of the cutting part can be avoided by operating the cutting transmission to the high speed side (operation at the cutting part). Speed can be secured above a certain level).

(The invention's effect)
According to the first aspect of the present invention, when the harvesting and harvesting machine includes a hydrostatic continuously variable transmission, the hydraulic motor of the hydrostatic continuously variable transmission is configured to be variable so that the driving force (torque) can be changed. It was possible to reduce the traveling speed of the aircraft while avoiding the decrease, and to improve the traveling performance of the harvesting machine.

  According to the first feature of the present invention, when the traveling speed of the airframe and the operating speed of the cutting part are synchronized, even if the traveling speed of the airframe is sufficiently low, the operating speed of the cutting part becomes low. It is possible to avoid excessive conditions (because the operating speed at the harvesting section can be secured above a certain level), and in the state of harvesting in the field, the crop has reached a part where the lodging is intense Improved cutting performance.

[II]
(Constitution)
The second feature of the present invention is that the harvesting harvester is configured as follows.
A hydrostatic continuously variable transmission that transmits engine power is provided, and the hydrostatic continuously variable transmission includes a hydraulic pump on the upper transmission side and a hydraulic motor on the lower transmission side. A transmission is provided on the lower transmission side of the hydraulic motor of the hydrostatic continuously variable transmission. The power of the transmission is branched in parallel to the traveling transmission system and the cutting transmission system, and the power of the traveling transmission system is transmitted to the traveling apparatus. The power of the cutting transmission system is configured to be transmitted to the cutting unit, and the cutting transmission system is provided with a cutting transmission.

(Function)
[II] -1
In the configuration in which the transmission is provided on the lower transmission side of the hydraulic motor of the hydrostatic continuously variable transmission, operating the transmission to the low speed side causes the power of the hydraulic motor of the hydrostatic continuously variable transmission to be reduced to the low speed side. When operating the transmission to the low speed side, if the discharge amount of the hydraulic pump of the hydrostatic continuously variable transmission is secured, sufficient driving force (torque) from the transmission to the lower transmission side The low-speed power provided with is transmitted.

According to the second aspect of the present invention, the engine power is transmitted to the traveling device via the hydraulic pump and hydraulic motor of the hydrostatic continuously variable transmission, the transmission, and the traveling transmission system. It is configured freely.
As a result, when the transmission is operated to the low speed side while the discharge amount of the hydraulic pump of the hydrostatic continuously variable transmission is secured, low speed power with sufficient driving force (torque) is transmitted to the traveling device. Therefore, even in a soft field with a large running resistance, the running speed of the low-speed aircraft can be obtained without a shortage of driving force (torque).

[II] -2
According to the second feature of the present invention, the power of the transmission is branched in parallel to the traveling transmission system and the cutting transmission system, and the power of the traveling transmission system is transmitted to the traveling apparatus. Is transmitted to the cutting part.
As a result, when the transmission is operated, the power shifted by the transmission is transmitted in parallel to the traveling device and the cutting unit, so that the traveling speed of the fuselage and the operating speed of the cutting unit are synchronized as in Patent Document 1. The state to do is obtained.

[II] -3
When the crops reach a part where crops are violently harvested in the field, it is necessary to make the running speed of the aircraft sufficiently low.
As a result, as described in the preceding paragraphs [II] -1 and 2, when the speed change device is operated to the low speed side to sufficiently reduce the traveling speed of the airframe, the operating speed of the cutting part is also sufficiently low. (The operating speed of the cutting part becomes too low), and there may be cases where stable cutting is not possible at the cutting part (if the operating speed above a certain level is not secured at the cutting part, stable cutting cannot be performed. Is).

  According to the second feature of the present invention, since the cutting transmission system is provided with the cutting transmission, the transmission speed is operated by operating the transmission to the low speed side as described in [II] -1 and 2 above. If the cutting speed is sufficiently low, the operating speed of the cutting part can be avoided by operating the cutting transmission gear to the high speed side (to ensure that the operating speed at the cutting part is above a certain level). Can do).

(The invention's effect)
According to the second feature of the present invention, when the harvesting and harvesting machine includes a hydrostatic continuously variable transmission, the transmission provided on the lower transmission side of the hydraulic motor of the hydrostatic continuously variable transmission is configured to be variable. By doing so, the traveling speed of the airframe can be lowered while avoiding a decrease in driving force (torque), and the traveling performance of the harvesting and harvesting machine can be improved.

  According to the second feature of the present invention, when configured so that the traveling speed of the aircraft and the operating speed of the cutting unit are synchronized, even if the traveling speed of the aircraft is sufficiently low, the operating speed of the cutting unit is reduced. It is possible to avoid excessive conditions (because the operating speed at the harvesting section can be secured above a certain level), and in the state of harvesting in the field, the crop has reached a part where the lodging is intense Improved cutting performance.

[1]
As shown in FIG. 1, a cutting unit 2 is supported by a front part of a machine body supported by right and left crawler type traveling devices 1, and a driving unit 3 is provided on the right side of the front part of the machine body. The threshing device 4 is provided on the left side of the rear part of the machine body, and the Glen tank 5 is provided on the right side of the rear part of the machine body to constitute a self-removing combine that is an example of a harvesting and harvesting machine.

  As shown in FIG. 2, an engine 6 is provided on the lower side of the driving unit 3, a mission case 8 is provided in the vicinity of the center of the left and right of the front part of the airframe, and the hydrostatic continuously variable transmission 7 is connected to the mission case 8. A belt transmission mechanism 9 having a tension clutch function is connected across the input shaft 7a of the hydrostatic continuously variable transmission 7 and the output shaft 6a of the engine 6 connected to the upper portion of the right side.

  As shown in FIG. 2, the output shaft 7b of the hydrostatic continuously variable transmission 7 is inserted into the transmission case 8 and connected to the low-speed gear 10 (transmission shaft 12) by a spline structure. 11 is fixed. A low-speed gear 14 and a high-speed gear 15 are fitted on the output shaft 13 so as to be relatively rotatable, and the low-speed gears 10 and 14 and the high-speed gears 11 and 15 are engaged. The shift member 16 slides on the output shaft 13 by a spline structure. And it is externally fitted so that it can rotate integrally. A belt transmission mechanism 17 having a tension clutch function is connected across the output shaft 13 and the input shaft 2 a of the cutting unit 2.

  As shown in FIG. 2, when the shift member 16 is engaged with the low speed gear 14 (low speed position), the power of the output shaft 7 b of the hydrostatic continuously variable transmission 7 is transmitted via the low speed gears 10, 14 and the shift member 16. When the shift member 16 is engaged with the high-speed gear 15 (high-speed position) when transmitted to the cutting unit 2 in a low-speed state, the power of the output shaft 7b of the hydrostatic continuously variable transmission 7 is transmitted to the high-speed gears 11 and 15 and the shift member 16. Is transmitted to the cutting unit 2 in a high speed state. As described above, the low-speed gears 10 and 14, the high-speed gears 11 and 15, the shift member 16, and the like constitute the cutting transmission 18 that can be shifted in two steps.

[2]
Next, the structure of the transmission system (transverse system) of the mission case 8 will be described.
As shown in FIG. 2, a transmission gear 19 is externally fitted to the transmission shaft 20 so as to be relatively rotatable, the transmission gear 19 is engaged with the low-speed gear 10, and a shift member 21 is slid onto the transmission shaft 20 by a spline structure. It is externally fitted so that it can rotate integrally. Transmission gears 22 and 23 are fixed to the transmission shaft 20, and a multi-plate friction parking brake 24 is provided at the end of the transmission shaft 20.

  As shown in FIG. 2, the shift member 21 is normally engaged with the transmission gear 19, and the power of the output shaft 7 b of the hydrostatic continuously variable transmission 7 is transmitted through the low-speed gear 10 and the transmission gear 19. 20. At the time of towing the aircraft due to a failure or the like, the right and left traveling devices 1 and the hydrostatic continuously variable transmission 7 can be shut off at the position of the shift member 21 by separating the shift member 21 from the transmission gear 19. Therefore, the airframe can be pulled without receiving the resistance of the hydrostatic continuously variable transmission 7.

  As shown in FIG. 2, the transmission gear 25 is fixed to the transmission shaft 26, and the transmission gears 22 and 25 are engaged. The right and left output gears 27 are fitted on the transmission shaft 26 so as to be relatively rotatable. The right and left output gears 27 are slid onto the transmission shaft 26 by a spline structure. It is externally fitted so that it can rotate integrally. Right and left axles 29 are provided, right and left transmission gears 30 fixed to the right and left axles 29 mesh with the right and left output gears 27, and the ends of the right and left axles 29 The sprocket 1a (refer FIG. 1) of the right and left traveling apparatuses 1 is connected to the part.

  As shown in FIG. 2, a spring 32 is provided between the receiving member 31 fixed to the transmission shaft 26 and the right occlusion portion 28, and a spring 32 is provided between the transmission gear 25 and the left occlusion portion 28. Thus, the right and left occlusion portions 28 are biased by the springs 32 to the occlusion side of the right and left output gears 27. A right oil chamber is formed between the right output gear 27 and the right occlusion portion 28, and a left oil chamber is formed between the left output gear 27 and the left occlusion portion 28. By supplying hydraulic oil to the left oil chamber, the right and left occlusion portions 28 can be separated from the right and left output gears 27 against the spring 32.

  As shown in FIG. 2, an occlusion-type right side clutch 33 is configured between the right output gear 27 and the right occlusion portion 28, and the occlusion is established between the left output gear 27 and the left occlusion portion 28. A left side clutch 33 of the equation is configured. When the right (left) occlusal portion 28 meshes with the right (left) output gear 27, the right (left) side clutch 33 is in a transmission state, and the right (left) occlusal portion 28 becomes right (left). By separating from the output gear 27, the right (left) side clutch 33 is disconnected.

  2, the power of the output shaft 7b of the hydrostatic continuously variable transmission 7 is such that the low speed gear 10, the transmission gear 19, the transmission shaft 20, the transmission gears 22, 25, the transmission shaft 26, The aircraft is transmitted straight to the right and left traveling devices 1 via the left occlusal portion 28, right and left output gears 27, right and left transmission gears 30, and right and left axles 29.

[3]
Next, the structure of the transmission system (turning system) of the mission case 8 will be described.
As shown in FIG. 2, a transmission gear 35 externally fitted to the transmission shaft 34 is engaged with a gear portion on the outer peripheral portion of the right occlusion portion 28, and the transmission shaft 34 and the transmission gear 35 are connected to each other. A slow swing clutch 36 is provided therebetween. The slow swing clutch 36 is configured as a frictional multi-plate type and is energized in a shut-off state, and is operated in a transmission state when hydraulic oil is supplied, and is operated in a shut-off state when the hydraulic oil is discharged.

  As shown in FIG. 2, a swing clutch case 37 is fitted on the transmission shaft 26 so as to be relatively rotatable, and a transmission gear 38 fixed to the transmission shaft 34 and a gear portion on the outer periphery of the swing clutch case 37 are engaged with each other. is doing. The swing clutch case 37 is configured symmetrically, and a right swing clutch 39 is provided between the swing clutch case 37 and the right output gear 27, and between the swing clutch case 37 and the left output gear 27. A left turning clutch 39 is provided. The right and left turning clutches 39 are configured as a friction multi-plate type, and are operated in a transmission state by supplying hydraulic oil. In this case, in the right and left turning clutch 39, the friction plates are arranged so as to be close to each other, and the right and left turning clutch 39 are in a semi-transmission state even when the hydraulic oil is discharged. ing.

  As a result, as shown in FIG. 2, when the slow swing clutch 36 is operated in the transmission state, the power of the transmission shaft 26 causes the right occlusal portion 28, the transmission gear 35, the slow swing clutch 36, the transmission shaft 34, and the transmission gear. The power is transmitted to the turning clutch case 37 as power that is lower in speed than the transmission shaft 26 in the same direction as the transmission shaft 26. When the right or left side clutch 33 is operated in the disconnected state and the right or left side clutch 39 is operated in the transmission state in the transmission state of the slow rotation clutch 36, the transmission shaft 26 is moved in the same direction as the transmission shaft 26. Also, low speed power is transmitted to the right or left output gear 27.

As shown in FIG. 2, a brake 40 is provided on the left side of the transmission shaft 34. The brake 40 is configured as a friction multi-plate type, and is operated in a braking state by supplying hydraulic oil, and is operated in a released state by discharging the hydraulic oil.
As a result, as shown in FIG. 2, when the brake 40 is operated in the braking state, the turning clutch case 37 is in the braking state via the transmission shaft 34 and the transmission gear 38. In the braking state of the brake 40, when the right or left side clutch 33 is operated in the disconnected state and the right or left turning clutch 39 is operated in the transmission state, the right or left output gear 27 is in the braking state.

  As shown in FIG. 2, a transmission gear 41 is externally fitted to the transmission shaft 34 so as to be relatively rotatable, and the transmission gears 23 and 41 are engaged with each other, and the reverse clutch 42 is interposed between the transmission shaft 34 and the transmission gear 41. Is provided. The reverse clutch 42 is configured as a frictional multi-plate type and is energized in a shut-off state, and is operated in a transmission state when hydraulic oil is supplied, and is operated in a shut-off state when the hydraulic oil is discharged.

  As a result, as shown in FIG. 2, when the reverse clutch 42 is operated in the transmission state, the power of the transmission shaft 20 is transmitted via the transmission gears 23 and 41, the reverse clutch 42, the transmission shaft 34 and the transmission gear 38. It is transmitted to the turning clutch case 37 as power in the direction opposite to that of the shaft 26. In the transmission state of the reverse clutch 42, when the right or left side clutch 33 is operated in the disconnected state and the right or left turning clutch 39 is operated in the transmission state, the power in the direction opposite to that of the transmission shaft 26 is right or left. To the output gear 27.

[4]
Next, the hydraulic circuit structure of the hydrostatic continuously variable transmission 7 will be described.
As shown in FIG. 5, the hydrostatic continuously variable transmission 7 includes an axial plunger type hydraulic pump 7P and a hydraulic motor 7M, and is configured by connecting the hydraulic pump 7P and the hydraulic motor 7M through a pair of oil passages 7c. Yes. A charge pump 44 is connected to the input shaft 7 a of the hydrostatic continuously variable transmission 7, and the charge pump 44 is driven by the input shaft 7 a of the hydrostatic continuously variable transmission 7.

  As shown in FIG. 5, a bypass oil passage 83 is connected across the oil passage 7 c of the hydrostatic continuously variable transmission 7, and a charge oil passage 45 extending from the charge pump 44 is connected to the bypass oil passage 83. The charge oil passage 45 is provided with a filter 49. A check valve 84, a throttle portion 85, and a relief valve 86 are provided between a portion of the bypass oil passage 83 to which the charge oil passage 45 is connected and the oil passage 7c of the hydrostatic continuously variable transmission 7. The relief pressure of the relief valve 86 is set to the highest pressure allowed as a whole of the hydrostatic continuously variable transmission 7. A supply oil passage 47 is connected across an oil tank 46 provided separately from the mission case 8 and the charge pump 44, and a filter 48 is provided in the supply oil passage 47.

  As shown in FIG. 5, a relief valve 50 is connected to the charge oil passage 45, and the relief valve 50 is connected to a case 51 that houses the hydrostatic continuously variable transmission 7. An oil passage 52 is connected across the case 51 and the oil tank 46, and an oil cooler 53 is provided in the oil passage 52. An oil passage 54 is connected across a portion between the charge pump 44 and the filter 48 in the supply oil passage 47 and a portion between the case 51 and the oil cooler 53 in the oil passage 52, and opens and closes to the oil passage 54. A valve 55 is provided. The on-off valve 55 is biased to the closed position, and is configured as a pilot type that opens when the pressure in the oil passage 52 reaches a predetermined low pressure.

With the above structure, the hydraulic oil in the oil tank 46 is supplied to the oil passage 7c of the hydrostatic continuously variable transmission 7 through the filter 48, the supply oil passage 47, the charge pump 44, and the charge oil passage 45, and surplus. The hydraulic oil is discharged to the case 51 through the relief valve 50. The hydraulic oil from each part of the hydrostatic continuously variable transmission 7 is discharged to the case 51, and the hydraulic oil in the case 51 passes through the oil passage 52 and the oil cooler 53 and is returned to the oil tank 46.
In this case, as shown in FIG. 5, when the pressure (back pressure) of the oil passage 52 increases due to the flow resistance of the oil cooler 53 and exceeds a predetermined low pressure, the on-off valve 55 is operated to the open position, and the oil passage The hydraulic oil 52 is supplied to the supply oil passage 47, and an increase in pressure in the oil passage 52 and the oil cooler 53 is suppressed.

[5]
Next, the operation structure of the hydrostatic continuously variable transmission 7 will be described.
As shown in FIGS. 4 and 5, the hydraulic pump 7 </ b> P of the hydrostatic continuously variable transmission 7 is configured to be continuously variable to the neutral position N, the forward side F, and the reverse side R. The speed change lever 43 provided in the operation unit 3 and the swash plate of the hydraulic pump 7P of the hydrostatic continuously variable transmission 7 are mechanically linked via a linkage link 80. The swash plate of the hydraulic pump 7P of the continuously variable transmission 7 is operated to operate the hydraulic pump 7P of the hydrostatic continuously variable transmission 7 to the neutral position N, the forward side F, and the reverse side R.

  As shown in FIGS. 4 and 5, the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is configured to be steplessly variable within the range of the lowest speed position L and the highest speed position H. An operation cylinder 56 for operating the swash plate of the hydraulic motor 7M of the step transmission 7 is provided. The oil passage 57 branches from the charge oil passage 45, and the oil passage 57 is connected to an oil chamber 56a that operates the operation cylinder 56 to the high speed side, and a spring 56b that urges the operation cylinder 56 to the low speed side is provided. ing. An electromagnetic operation type pressure control valve 58 is provided in the oil passage 57, and when the pressure in the oil chamber 56a of the operation cylinder 56 rises, the operation cylinder 56 operates on the high speed side against the spring 56b of the operation cylinder 56. When the pressure in the oil chamber 56a of the operation cylinder 56 decreases, the operation cylinder 56 is actuated to the low speed side by the spring 56b of the operation cylinder 56.

As shown in FIG. 4, a travel shift switch 81 is provided in the lower grip portion 43 a of the shift lever 43 at the lower grip portion 43 a of the shift lever 43. The travel shift switch 81 is configured as a lever switch type or a seesaw switch type that can be operated to a neutral position, an upper high speed position, and a lower low speed position, and is biased to the neutral position. The operation signal is input to the control device 79. A potentiometer 82 for detecting the position of the swash plate of the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is provided, and the detected value of the potentiometer 82 is input to the control device 79. The hydrostatic continuously variable transmission 7 The operation unit 3 is provided with a display unit 87 for displaying the position of the swash plate of the hydraulic motor 7M.
Thus, based on the operation of the travel shift switch 81, the control device 79 operates the pressure control valve 58, and the operation cylinder 56 operates.

  As shown in FIG. 4, when the travel shift switch 81 is operated to the high speed position, the operating oil is supplied to the oil chamber 56a by the pressure control valve 58 to the operation cylinder 56, and the operation cylinder 56 operates to the high speed side. The hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is operated to the high speed side. When the travel shift switch 81 is operated to the neutral position, the operation cylinder 56 is stopped by the pressure control valve 58 at that time, the operation of the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is stopped, and the hydrostatic type The position of the swash plate of the hydraulic motor 7M of the continuously variable transmission 7 is displayed on the display unit 87.

As shown in FIG. 4, when the travel shift switch 81 is operated to the low speed position, the hydraulic oil in the oil chamber 56a is discharged to the operation cylinder 56 by the pressure control valve 58, and the operation cylinder 56 operates to the low speed side. The hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is operated to the low speed side. When the travel shift switch 81 is operated to the neutral position, the operation cylinder 56 is stopped by the pressure control valve 58 at that time, the operation of the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is stopped, and the hydrostatic type The position of the swash plate of the hydraulic motor 7M of the continuously variable transmission 7 is displayed on the display unit 87.
In this way, by operating the travel shift switch 81 to the high speed and low speed positions, the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 can be continuously operated to the high speed side and the low speed side.

When the swash plate of the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is operated to the high speed side beyond a preset low speed setting position, the cutting transmission 18 is moved at a low speed by an actuator (not shown). Automatically operated to position. When the swash plate of the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is operated to the low speed side beyond the low speed setting position, the cutting transmission 18 is automatically operated to the high speed position by the actuator.
The state in which the swash plate of the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 described above is operated to the low speed side beyond the low speed setting position and the cutting transmission 18 is operated to the high speed position is the cutting operation in the field. This corresponds to the case where the area where crop lodging is intense is reached.

[6]
Next, a hydraulic unit 59 that supplies and discharges hydraulic oil to and from the right and left side clutches 33 (the right and left occlusal portions 28), the right and left turning clutch 39, the slow turning clutch 36, the brake 40, and the reverse rotation clutch 42. Will be described.
As shown in FIGS. 2 and 3, the hydraulic unit 59 is connected to the lower part of the left side portion of the mission case 8. The hydraulic pump 60 is connected to the input shaft 7 a of the hydrostatic continuously variable transmission 7, and the hydraulic pump 60 is driven by the input shaft 7 a of the hydrostatic continuously variable transmission 7. An oil passage 61 extending from the oil pressure unit 59 is connected to the hydraulic unit 59.

  As shown in FIG. 3, a supply oil passage 62 is connected across the transmission case 8 and the hydraulic pump 60, and an oil cooler 63 is provided in the supply oil passage 62. A filter 64 is provided in a portion between the oil cooler 63. A bypass oil passage 65 is connected across a portion of the supply oil passage 62 on the mission case 8 side and a portion of the supply oil passage 62 between the oil cooler 63 and the filter 64. The resistance is smaller than the flow path resistance of the oil cooler 63.

  As a result, as shown in FIG. 3, the lubricating oil stored in the transmission case 8 is divided into the oil cooler 63 and the bypass oil passage 65 as hydraulic oil, and merges and passes through the filter 64 to pass through the hydraulic pump 60. To be supplied. The hydraulic oil of the hydraulic pump 60 is supplied to the hydraulic unit 59 via the oil passage 61, and the hydraulic oil discharged from each part of the hydraulic unit 59 is returned to the transmission case 8 as will be described later.

  As shown in FIG. 3, inside the hydraulic unit 59, there are a right turn control valve 67, a left turn control valve 68, a first relief valve 69, an unload valve 70, a second relief valve 76, a proportional control valve 71, and a turn switching. A control valve 72 and pilot operation valves 73 and 74 are provided. An oil passage 61 of the hydraulic pump 60 is connected to the hydraulic unit 59, and right and left turning control valves 67 and 68, a first relief valve 69, and an unload valve 70 are connected in parallel to the oil passage 66 connected to the oil passage 61. It is connected.

  As shown in FIG. 3, the right turn control valve 67 is connected to the right side clutch 33 (right occlusion portion 28) and the right turn clutch 39, and the left turn control valve 68 is connected to the left side clutch 33 ( It is connected to the left occlusal portion 28) and the left turning clutch 39. The right and left turning control valves 67 and 68 are configured to be electromagnetically operated to supply positions 67a and 68a and discharge positions 67b and 68b, and are biased to the discharge positions 67b and 68b. The unload valve 70 is configured to be electromagnetically operated so as to be freely operated at the shut-off position 70a and the discharge position 70b, and is biased to the shut-off position 70a.

  As shown in FIG. 3, the second relief valve 76 is connected to the oil passage 75 branched from the right and left side clutches 33 (the right and left occlusal portions 28), and the proportional control valve 71 and the swing are connected to the oil passage 75. The switching control valve 72 is connected in series, and the turning switching control valve 72 is connected to the slow turning clutch 36, the brake 40 and the reverse rotation clutch 42. The proportional control valve 71 is configured as an electromagnetic operation type, and can control the pressure of hydraulic oil. The turning switching control valve 72 is configured in a pilot-operated manner that can be operated to a slow turning position 72a, a trust turning position 72b, and a super turning position 72c, and is biased to the slow turning position 72a. In this case, the relief pressure of the first relief valve 69 is set to a relatively high value, and the relief pressure of the second relief valve 76 is set to a relatively low value.

As shown in FIG. 3, the pilot operation valve 73 is configured so that the pilot hydraulic oil branched from the oil passage 75 is supplied to the turning switching control valve 72 and operated to the pivot turning position 72 b. The pilot operation valve 74 is configured to supply the pilot hydraulic oil thus supplied to the turning switching control valve 72 and to operate it to the super turning position 72c. A drain oil passage (not shown) is formed on the connection surface (mating surface) between the hydraulic unit 59 and the transmission case 8, and includes a right turn control valve 67, a left turn control valve 68, a first relief valve 69, The hydraulic oil of the unload valve 70, the second relief valve 76, the proportional control valve 71, the turning switching control valve 72, and the pilot operation valves 73 and 74 is returned to the mission case 8 through the drain oil passage.
The right and left turning control valves 67 and 68, the unload valve 70, the proportional control valve 71, and the pilot operation valves 73 and 74 are controlled by a control device as described in [7] [8] [9] [10] described later. 79 is operated.

[7]
Next, a straight traveling state by the steering lever 77 will be described.
As shown in FIGS. 1 and 4, a steering lever 77 that can be operated to the right and left is provided in the operating unit 3, and the operation position of the steering lever 77 is input to the control device 79. Is configured to be freely operated at a straight traveling position N, right and left first turning positions R1, L1, and right and left second turning positions R2, L2. A turning mode switch 78 is provided in the operation unit 3, and an operation position of the turning mode switch 78 is input to the control device 79, and the turning mode switch 78 sets a slow turning position, a trust turning position, and a super trust turning position. I have.

  As shown in FIGS. 2, 3, and 4, regardless of the operation position of the turning mode switch 78, when the steering lever 77 is operated to the straight traveling position N, the right and left turning control valves 67, 68 are moved to the discharge positions 67b, The unload valve 70 is operated to the discharge position 70b. As a result, the hydraulic oil is discharged from the right and left side clutch 33 (right and left occlusion portion 28) and the right and left turning clutch 39, and the right and left side clutch 33 (right and left occlusion portion 28). Is operated in the transmission state, and the right and left turning clutch 39 are operated in the half transmission state. The proportional control valve 71 operates the slow turn and reverse clutches 36 and 42 to the disconnected state, and the brake 40 to the released state.

  As shown in FIG. 2 and the preceding item [2], the power of the output shaft 7b of the hydrostatic continuously variable transmission 7 is such that the low-speed gear 10, the transmission gear 19, the transmission shaft 20, the transmission gears 22 and 25, and the transmission shaft 26. The right and left occlusal portions 28, the right and left output gears 27, the right and left transmission gears 30, and the right and left axles 29 are transmitted to the right and left traveling devices 1 so that the aircraft moves straight. To do.

[8]
Next, the slow turning state by the steering lever 77 will be described.
As shown in FIGS. 2, 3, and 4, when the turning mode switch 78 is operated to the slow turning position, the turning switching control valve 72 is operated to the slow turning position 72 a by the pilot operation valves 73 and 74. Accordingly, when the steering lever 77 is operated to the right first turning position R1, the right turning control valve 67 is operated to the supply position 67a, the unload valve 70 is operated to the cutoff position 70a, and the right side The hydraulic oil is supplied to the clutch 33 (right occlusion portion 28) and the right turning clutch 39, the right side clutch 33 (right occlusion portion 28) is operated to be disconnected, and the right turning clutch 39 is in a transmission state. To be operated.

  As shown in FIG. 2, since the left swing clutch 39 is in a semi-transmission state, the power of the left side clutch 33 (the left occlusion portion 28) is transferred from the left output gear 27 and the left swing clutch 39 to the right. Is transmitted to the right output gear 27 through the turning clutch 39, and the power slightly lower than the transmission shaft 26 in the same direction as the transmission shaft 26 is transmitted to the right output gear 27. As a result, the aircraft gently turns to the right.

  As shown in FIGS. 2, 3, and 4, when the steering lever 77 is operated to the first right turning position R1, the right turning control valve 67 is operated to the supply position 67a as described above, and the unload valve 70 is moved. Simultaneously with the operation to the shut-off position 70a, hydraulic oil begins to be supplied to the slow swing clutch 36 via the proportional control valve 71 and the swing switching control valve 72 (slow swing position 72a), and the steering lever 77 is The proportional control valve 71 increases the operating pressure of the slow turning clutch 36 as the right first turning position R1 is operated to the right second turning position R2.

  As shown in FIGS. 2, 3, and 4, as the operating pressure of the slow swing clutch 36 is increased by the proportional control valve 71 based on the operation position of the steering lever 77, the power of the transmission shaft 26 is changed to the right. And the transmission shaft 26 in the same direction as the transmission shaft 26 via the occlusal portion 28, the transmission gear 35, the slow turning clutch 36, the transmission shaft 34, the transmission gear 38, the turning clutch case 37 and the right turning clutch 39. It is transmitted to the right output gear 27 as power.

  In this case, as shown in FIG. 2, the power from the left side clutch 33 (the left occlusal portion 28) and the power from the slow turning clutch 36 are simultaneously transmitted to the right output gear 27. In the range where the operating pressure of the slow swing clutch 36 is low, the power from the left side clutch 33 (left occlusion portion 28) overcomes the power from the slow swing clutch 36, and the left side clutch 33 (left occlusion) The right output gear 27 is driven by the power from the section 28). As a result, the airframe gradually turns to the right when the operating pressure of the slow swing clutch 36 is low.

  Next, when the operating position of the steering lever 77 approaches the right second turning position R2 and the operating pressure of the slow turning clutch 36 becomes high, the power from the slow turning clutch 36 is changed to the left side as shown in FIG. Overcoming the power from the clutch 33 (the left occlusal portion 28), the right output gear 27 is driven by the power from the slow turning clutch 36. In this state, the right output gear 27 is driven by the power from the slow turning clutch 36, rather than the right output gear 27 being driven by the power from the left side clutch 33 (the left occlusal portion 28). However, the right output gear 27 is driven at a low speed, and the aircraft turns slowly to the right.

  As shown in FIGS. 2, 3, and 4, when the steering lever 77 is operated to the first left turning position L1, the left turning control valve 68 is operated to the supply position 68a, and the unload valve 70 is turned to the shut-off position 70a. And hydraulic oil is supplied to the left side clutch 33 (left occlusal portion 28) and the left turning clutch 39, and the left side clutch 33 (left occlusion portion 28) is operated to be disconnected, and left Is turned to the transmission state. At the same time, the same operation as described above is performed, and the aircraft gradually turns to the left. When the steering lever 77 is operated from the left first turning position L1 to the left second turning position L2, the same operation as described above is performed, and the aircraft turns slowly to the left.

[9]
Next, the belief turning state by the steering lever 77 will be described.
As shown in FIGS. 2, 3, and 4, when the turning mode switch 78 is operated to the belief turning position, the turning switch control valve 72 is operated to the belief turning position 72 b by the pilot operation valves 73 and 74.
Accordingly, when the steering lever 77 is operated to the right first turning position R1, the right turning control valve 67 is operated to the supply position 67a, the unload valve 70 is operated to the cutoff position 70a, and the right side The hydraulic oil is supplied to the clutch 33 (right occlusion portion 28) and the right turning clutch 39, the right side clutch 33 (right occlusion portion 28) is operated to be disconnected, and the right turning clutch 39 is in a transmission state. To be operated. In this case, since the left turning clutch 39 is in a semi-transmission state, the aircraft gradually turns to the right as described in [8] above.

  As shown in FIGS. 2, 3, and 4, when the steering lever 77 is operated to the first right turning position R1, the right turning control valve 67 is operated to the supply position 67a as described above, and the unload valve 70 is moved. Simultaneously with the operation to the shut-off position 70a, hydraulic oil begins to be supplied to the brake 40 via the proportional control valve 71 and the turn switching control valve 72 (the pivot turn position 72b), and the steering lever 77 is moved to the right. The proportional control valve 71 increases the operating pressure of the brake 40 as the first turning position R1 is operated to the right second turning position R2.

  As shown in FIGS. 2, 3, and 4, as the operating pressure of the brake 40 is increased by the proportional control valve 71 based on the operation position of the steering lever 77, the transmission shaft 34, the transmission gear 38, the turning A braking force is applied to the right output gear 27 via the clutch case 37 and the right turning clutch 39.

  In this case, as shown in FIG. 2, the power from the left side clutch 33 (the left occlusal portion 28) and the braking force of the brake 40 are simultaneously transmitted to the right output gear 27. In a range where the operating pressure of the brake 40 is low, the power from the left side clutch 33 (the left occlusion portion 28) overcomes the braking force of the brake 40 and the force from the left side clutch 33 (the left occlusion portion 28) The right output gear 27 is driven by the power. As a result, when the operating pressure of the brake 40 is in a low pressure range, the aircraft gradually turns to the right.

  Next, when the operating position of the steering lever 77 approaches the right second turning position R2 and the operating pressure of the brake 40 becomes high, the braking force of the brake 40 is applied to the left side clutch 33 (left The power output from the occlusal portion 28) is overcome, the braking force of the brake 40 causes the right output gear 27 to enter the braking state, and the aircraft turns right.

  As shown in FIGS. 2, 3, and 4, when the steering lever 77 is operated to the first left turning position L1, the left turning control valve 68 is operated to the supply position 68a, and the unload valve 70 is turned to the shut-off position 70a. And hydraulic oil is supplied to the left side clutch 33 (left occlusal portion 28) and the left turning clutch 39, and the left side clutch 33 (left occlusion portion 28) is operated to be disconnected, and left Is turned to the transmission state. At the same time, the same operation as described above is performed, and the aircraft gradually turns to the left. When the steering lever 77 is operated from the left first turning position L1 to the left second turning position L2, the same operation as described above is performed, and the aircraft turns to the left.

[10]
Next, the super turning state by the steering lever 77 will be described.
As shown in FIGS. 2, 3, and 4, when the turning mode switch 78 is operated to the super turning position, the turning control valve 72 is operated to the super turning position 72c by the pilot operation valves 73 and 74.
Accordingly, when the steering lever 77 is operated to the right first turning position R1, the right turning control valve 67 is operated to the supply position 67a, the unload valve 70 is operated to the cutoff position 70a, and the right side The hydraulic oil is supplied to the clutch 33 (right occlusion portion 28) and the right turning clutch 39, the right side clutch 33 (right occlusion portion 28) is operated to be disconnected, and the right turning clutch 39 is in a transmission state. To be operated. In this case, since the left turning clutch 39 is in a semi-transmission state, the aircraft gradually turns to the right as described in [8] above.

  As shown in FIGS. 2, 3, and 4, when the steering lever 77 is operated to the first right turning position R1, the right turning control valve 67 is operated to the supply position 67a as described above, and the unload valve 70 is moved. Simultaneously with the operation to the shut-off position 70a, the hydraulic oil begins to be supplied to the reverse rotation clutch 42 via the proportional control valve 71 and the turning switching control valve 72 (super-reliable turning position 72c). Is operated from the right first turning position R1 to the right second turning position R2, the operating pressure of the reverse clutch 42 is increased by the proportional control valve 71.

  As shown in FIGS. 2, 3, and 4, as the operating pressure of the reverse clutch 42 is increased by the proportional control valve 71 based on the operation position of the steering lever 77, the power of the transmission shaft 20 is transmitted to the transmission gear. 23, 41, reverse clutch 42, transmission shaft 34, transmission gear 38, turning clutch case 37, and right turning clutch 39 are transmitted to the right output gear 27 as power in the direction opposite to that of the transmission shaft 26.

  In this case, as shown in FIG. 2, the power from the left side clutch 33 (the left occlusal portion 28) and the power from the reverse clutch 42 are transmitted to the right output gear 27 at the same time. In the range where the operating pressure of the reverse clutch 42 is low, the power from the left side clutch 33 (the left occlusion portion 28) overcomes the power from the reverse clutch 42 and the left side clutch 33 (the left occlusion portion 28). ) Drives the right output gear 27. As a result, when the operating pressure of the reverse clutch 42 is in a low pressure range, the aircraft gradually turns to the right.

  Next, when the operating position of the steering lever 77 approaches the right second turning position R2 and the operating pressure of the reverse clutch 42 becomes high, the power from the reverse clutch 42 is changed to the left side clutch 33 as shown in FIG. The right output gear 27 is driven by the power from the reverse clutch 42 by overcoming the power from the (left occlusal portion 28). In this state, the right output gear 27 is driven in the opposite direction with respect to the left output gear 27, and the aircraft turns to the right.

  As shown in FIGS. 2, 3, and 4, when the steering lever 77 is operated to the first left turning position L1, the left turning control valve 68 is operated to the supply position 68a, and the unload valve 70 is turned to the shut-off position 70a. And hydraulic oil is supplied to the left side clutch 33 (left occlusal portion 28) and the left turning clutch 39, and the left side clutch 33 (left occlusion portion 28) is operated to be disconnected, and left Is turned to the transmission state. At the same time, the same operation as described above is performed, and the aircraft gradually turns to the left. When the steering lever 77 is operated from the left first turning position L1 to the left second turning position L2, the same operation as described above is performed, and the aircraft turns to the left.

[First Alternative Embodiment of the Invention]
The hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is not continuously operated to the high speed side and the low speed side as in the above-mentioned [Best Mode for Carrying Out the Invention]. The hydraulic motor 7M of the hydraulic continuously variable transmission 7 may be configured to be operated to a plurality of operation positions (for example, five operation positions).

In this case, a plurality of operation positions can be arbitrarily changed and stored according to the driver's preference, and by operating an operation switch (not shown), a plurality of operation positions can be stored. Configure so that one can be selected.
The preset low-speed setting position is compared with the selected operation position, and when the selected operation position is higher than the low-speed predetermined position, the cutting transmission 18 is an actuator (not shown). Thus, when the selected operation position is at a lower speed side than the predetermined low speed position, the cutting transmission 18 is automatically operated to the high speed position by the actuator.

[Second Embodiment of the Invention]
Instead of the above-mentioned [Best Mode for Carrying Out the Invention] [First Alternative Embodiment], the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is moved by the operating cylinder 56 at a high speed for traveling. You may comprise so that it may operate in three positions, a position, the medium-speed position for cutting work, and the low-speed position for fall harvesting work which harvests a crop with intense lodging.

  In this case, an actuator (not shown) for operating the cutting transmission 18, a cutting clutch (not shown) capable of transmitting and blocking the power transmitted to the cutting unit 2, and an actuator (not shown) for operating the cutting clutch. ), A travel shift switch (not shown) and a cutting shift switch (not shown) provided in the grip 43a (see FIG. 4) of the transmission lever 43, and the cutting transmission 18 and the cutting clutch are as follows. It may be configured to be automatically operated.

As shown in FIG. 6, the traveling state, the standard cutting state, and the low-speed cutting state are set in the control device 79.
The traveling state is a state where the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is operated to the high speed position, the cutting clutch is operated to the disengaged state, and the cutting transmission 18 is operated to the low speed position. The standard cutting state is a state in which the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is operated to the medium speed position, the cutting clutch is operated to the transmission state, and the cutting transmission 18 is operated to the low speed position. The low speed cutting state is a state in which the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is operated to the low speed position, the cutting clutch is operated to the transmission state, and the cutting transmission 18 is operated to the high speed position.

As shown in FIG. 6, when the travel shift switch is pushed in the state where the traveling state is set, the standard cut state is set, and in the state where the standard cut state is set, the travel shift switch is pushed. Then, the traveling state is set. Thus, every time the travel shift switch is pushed, the traveling travel state and the standard cutting state are alternately set.
In this case, even when the mowing shift switch is pushed in the state where the traveling state is set, this pushing operation is ignored and the traveling state is maintained. When the travel shift switch is pushed and the standard cutting state is set, when the cutting shift switch is pushed, the low-speed cutting state is set.

As shown in FIG. 6, when the cutting gear shift switch is pushed in the state where the standard cutting state is set, the low-speed cutting state is set. When the cutting shift switch is pushed in the state where the low-speed cutting state is set, the standard cutting state is set. Thus, every time the cutting shift switch is pushed, the standard cutting state and the low-speed cutting state are alternately set.
In this case, even if the travel shift switch is pushed in the state where the low-speed cutting state is set, this pushing operation is ignored and the low-speed cutting state is maintained. When the travel shift switch is pushed in the state where the standard cut state is set by pushing the cut gear shift switch, the moving travel state is set.

[Third Another Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention] [First Alternative Embodiment of the Invention] [Second Alternative Embodiment of the Invention], the following configuration may be provided.
As shown in FIGS. 4 and 7, when operating oil is supplied to and discharged from the oil chamber 56a to the operating cylinder 56 by the travel shift switch 81 and the pressure control valve 58, the pressure in the oil chamber 56a of the operating cylinder 56 is the minimum pressure B1. And operated within the range of maximum pressure B2. The relationship between the position of the swash plate of the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 and the pressure of the oil chamber 56a of the operating cylinder 56 in a no-load state where no load is applied to the hydrostatic continuously variable transmission 7 ( A1) is known in advance, and the minimum pressure B1 of the oil chamber 56a of the operating cylinder 56 corresponds to the minimum speed position L of the hydraulic motor 7M (swash plate) of the hydrostatic continuously variable transmission 7, and the operating cylinder The maximum pressure B2 of 56 oil chambers 56a (set by the relief valve 50 (see FIG. 5)) corresponds to the highest speed position H of the hydraulic motor 7M (swash plate) of the hydrostatic continuously variable transmission 7. Yes.

  As shown in FIG. 7, the pressure in the oil chamber 56a of the operating cylinder 56 is maintained at a predetermined pressure (the swash plate of the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is in a position corresponding to the predetermined pressure. In the operated state), when the load applied to the hydrostatic continuously variable transmission 7 increases, the swash plate of the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is displaced to the low speed side by the load. Accordingly, the relationship between the position of the swash plate of the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 and the pressure of the oil chamber 56a of the operation cylinder 56 according to the load applied to the hydrostatic continuously variable transmission 7 ( A2, A3, etc.) are known in advance.

  As shown in FIG. 7, with the pressure of the oil chamber 56a of the operating cylinder 56 maintained at a predetermined pressure, the swash plate of the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is controlled by a potentiometer 82 (see FIG. 4). By detecting the position, it is possible to determine which relationship (A1, A2, A3, etc.) the current state is based on and to detect the load applied to the hydrostatic continuously variable transmission 7. The load that the relief valve 86 shown in FIG. 5 opens is also known in advance.

  As described above, the load applied to the hydrostatic continuously variable transmission 7 is detected from the pressure of the oil chamber 56a in the operating cylinder 56 and the position of the swash plate of the hydraulic motor 7M of the hydrostatic continuously variable transmission 7. In this case, the position of the swash plate of the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is changed until the load applied to the hydrostatic continuously variable transmission 7 reaches a load slightly smaller than the load that the relief valve 86 opens. Not. When the load applied to the hydrostatic continuously variable transmission 7 reaches a load slightly smaller than the load opened by the relief valve 86, the hydraulic motor 7M of the hydrostatic continuously variable transmission 7 is operated to the low speed side by the operating cylinder 56. Thus, the state where the relief valve 86 is opened is avoided.

[Fourth Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention] [First Alternative Embodiment of the Invention] to [Third Alternative Embodiment of the Invention], as shown in FIG. A continuously variable transmission 88 (such as a belt-type continuously variable transmission or a toroidal core continuously variable transmission) may be connected to the output shaft 7b (hydraulic motor 7M).
As a result, as shown in FIG. 8, instead of operating the hydraulic motor 7M of the hydrostatic continuously variable transmission 7, the power of the output shaft 7b (hydraulic motor 7M) of the hydrostatic continuously variable transmission 7 is changed. It transmits to the apparatus 88, operates the transmission 88, and is comprised so that the motive power of the transmission 88 may be transmitted to the cutting transmission 18 and the transmission shaft 20 from the transmission shaft 12. FIG.

[Fifth Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention] [First Alternative Embodiment of the Invention] to [Fourth Alternative Embodiment of the Invention], the mowing transmission 18 is a continuously variable transmission type (static hydrostatic type). A step transmission, a belt type continuously variable transmission, a toroidal core type continuously variable transmission, or the like may be used.

Combine side view Longitudinal front view of the mission case Diagram showing the hydraulic circuit structure of the hydraulic unit The figure which shows the relationship between a shift lever, a steering lever, a turning mode switch, a hydraulic unit, an operation cylinder, and a pressure control valve The figure which shows the hydraulic circuit structure of the hydrostatic continuously variable transmission The figure which shows a traveling state, a standard cutting state, and a low-speed cutting state in 2nd another form of implementation of invention. The figure which shows the relationship between the position of the swash plate of the hydraulic motor of the hydrostatic continuously variable transmission, and the pressure of the oil chamber of an operation cylinder in 3rd another form of implementation of invention. In the fourth alternative embodiment of the invention, a longitudinal front view of the vicinity of the hydrostatic continuously variable transmission and the transmission

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Traveling device 2 Cutting part 6 Engine 7 Hydrostatic continuously variable transmission 7P Hydraulic pump of hydrostatic continuously variable transmission 7M Hydraulic motor of hydrostatic continuously variable transmission 18 Cutting transmission 88 Transmission

Claims (2)

Comprising a hydrostatic continuously variable transmission to which engine power is transmitted, the hydrostatic continuously variable transmission comprising a hydraulic pump on the upper transmission side and a hydraulic motor on the lower transmission side;
The hydraulic motor of the hydrostatic continuously variable transmission is configured to be variable,
The power of the hydraulic motor of the hydrostatic continuously variable transmission is branched in parallel to a travel transmission system and a cutting transmission system, and the power of the travel transmission system is configured to be transmitted to the travel device,
A harvesting and harvesting machine configured to transmit the power of the harvesting transmission system to a harvesting unit, and the harvesting transmission system includes a harvesting transmission. Comprising a hydrostatic continuously variable transmission to which engine power is transmitted, the hydrostatic continuously variable transmission comprising a hydraulic pump on the upper transmission side and a hydraulic motor on the lower transmission side;
A transmission is provided on the lower transmission side of the hydraulic motor of the hydrostatic continuously variable transmission,
The power of the transmission is branched in parallel to a travel transmission system and a cutting transmission system, and the power of the travel transmission system is transmitted to the travel device,
A harvesting and harvesting machine configured to transmit the power of the harvesting transmission system to a harvesting unit, and the harvesting transmission system includes a harvesting transmission.

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