JP2013040632A - Traveling transmission device of farm working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a traveling transmission device of a farm working machine which can suppress or eliminate a change of a speed accompanied by the switching of transmission from HST transmission to HMT transmission.SOLUTION: There is set, as a set reference swash plate angle c, a swash plate angle in a speed change state that a stepless speed change part at the HST transmission and at non-loaded drive outputs a speed equivalent to an integral rotation appearance speed V which makes the integral rotation of a sun gear, a carrier and a ring gear appear. When the output speed of the stepless speed change part at the HST transmission becomes the integral rotation appearance speed V, a swash plate is returned to a low-speed side by a set return angle E while keeping an HST clutch and an HMT clutch in on-states if it is detected that a swash plate angle of a hydraulic pump is shifted to a high-speed side rather than the set reference swash plate angle c on the basis of detection information by a swash plate angle sensor, and after that, the HST clutch and the HMT clutch are switched in order to switch and set transmission to the HMT transmission from the HST transmission.

Description

  The present invention includes a hydrostatic continuously variable transmission that acts to input and shift the driving force from the engine and shift the output driving force along the HST shift line, and the driving force from the engine A transmission having a planetary transmission unit that acts to input and synthesize a variable speed driving force from a continuously variable transmission unit and output the combined driving force to be shifted along the HMT shift line by a shift of the continuously variable transmission unit. HST transmission for setting the HST transmission and the HMT clutch for setting the HMT transmission to output the shift driving force output from the continuously variable transmission unit from the output rotating body to the traveling device by switching between the HST clutch and the planetary transmission. The transmission gear is configured to switch the combined driving force output from the output to the HMT transmission output from the output rotating body to the traveling device, and based on a shift command from a shift operation tool. About traveling transmission apparatus for agricultural machine comprising the HST clutch and shift control means for controlling switching the HMT clutch while shift control hydraulic pump which constitutes the variable part.

  Agricultural work machines may be repeatedly switched between forward and backward, such as when changing the direction at the end of a work line. The traveling transmission device for an agricultural machine described above has output characteristics as shown in FIG. 6, and the output speed is set to the HST shift line by performing a shift operation to the forward side and the reverse side across the neutral state of the continuously variable transmission unit. Thus, the aircraft can be switched between forward and backward by simply performing a simple shift operation that does not require a special operation for forward / reverse switching.

  Conventionally, for example, Patent Document 1 discloses a traveling power transmission device of this type. In the one described in Patent Document 1, a hydraulic continuously variable transmission, a planetary gear mechanism, and two hydraulic clutches are provided in a transmission system that transmits engine output to front and rear wheels, and connection between the two hydraulic clutches is switched. Thus, a drive system in the HST mode is configured, and the driving force output from the motor output shaft of the hydraulic continuously variable transmission is transmitted to the front and rear wheels without being transmitted to the planetary gear mechanism. Further, by switching the connection of the two hydraulic clutches, an HMT mode drive system is configured, and the driving force output from the motor output shaft of the hydraulic continuously variable transmission is transmitted to the planetary gear mechanism to be transmitted to the planetary gear. The driving force from the hydraulic continuously variable transmission and the driving force from the engine are combined by the mechanism, and the combined driving force output from the planetary gear mechanism is transmitted to the front and rear wheels.

JP 2001-108061 A

  When the switching of the clutch mechanism for switching the setting from the HST transmission to the HMT transmission is completed and the driving force from the engine is transmitted to the planetary transmission unit, the sun gear, the carrier and the ring gear of the planetary transmission unit are When it rotates integrally, the switching of the clutch mechanism for switching the setting from the HST transmission to the HMT transmission is smoothly performed from the relationship of the relative phase of the transmission upper member and the transmission lower member constituting the clutch mechanism. It will be. However, the output speed of the continuously variable transmission unit is detected, and the continuously variable transmission unit at the time when the setting is switched from the HST transmission to the HMT transmission is added to the planetary transmission unit after the setting is switched. When the clutch mechanism switching control is performed based on the detection result of the output speed of the continuously variable transmission so as to have an output speed (integral rotation appearing speed) equivalent to that which makes the integrated rotation appear. There is a tendency that the traveling speed changes immediately after switching from HST transmission to HMT transmission. This point will be described with reference to FIGS.

  FIG. 10 is a graph showing output characteristics of the speed change transmission in the travel transmission device. The vertical axis is a speed line indicating the rotational speed of the driving force output from the transmission. The horizontal axis passes through the position where the rotational speed of the vertical axis is zero “0”, and is an operation position line L indicating the swash plate position of the hydraulic pump constituting the continuously variable transmission. “N” in the operation position line L is a swash plate neutral operation position for setting the continuously variable transmission unit in a neutral state. “A” in the operation position line L is a set forward high speed position set as the maximum high speed position on the forward side of the swash plate operated by the shift control. “−max” of the operation position line L is a set reverse high-speed position set as the maximum high-speed position on the reverse side of the swash plate operated by the shift control.

  The shift line S through which the rotational speed passes through zero “0” is an unloaded HST shift line S indicating the setting of the HST transmission and the change in the output speed of the transmission in the no-load drive. A shift line area SF corresponding to a position between the swash plate positions “n” and “a” in the no-load HST shift line S indicates a change in output speed on the forward side. This is a no-load HST shift line SF. The shift line area SR corresponding to the position between the swash plate positions “n” and “−max” in the no-load HST shift line S indicates a change in the output speed on the reverse side, and the reverse side This is an unloaded HST shift line SR. A shift line M continuous to the no-load HST shift line S is an unload HMT shift line M indicating the setting of the HMT transmission and the change in the output speed of the transmission in the no-load drive.

  A shift line SA whose rotational speed passes through zero “0” is a load HST shift line SA indicating the setting of the HST transmission and the change of the output speed of the transmission in the load drive. An inclined line MA intersecting the load HST shift line SA is a load HMT shift line MA indicating the setting of the HMT transmission and a change in the output speed of the transmission in the load drive.

  Since the driving load applied to the transmission is applied to the swash plate of the hydraulic pump constituting the continuously variable transmission, the no-load HST shift line SF and HMT shift line M and the load HST shift line SA and HMT shift line. It will be different from MA. That is, the inclination angle of the load HST shift line SA with respect to the operation position line L becomes a gentler inclination angle than the inclination angle of the no-load HST shift line S with respect to the operation position line L. Set forward high speed position to maintain speed continuity at the point where setting of HST transmission and HMT transmission is switched in a simple configuration in which rotation of the output shaft of the continuously variable transmission section is input to the planetary transmission section without increasing or decreasing When “a” is set to a position before the actual forward maximum speed position of the swash plate that is actually operable in the hydraulic pump of the continuously variable transmission unit, the no-load HST shift line S and HMT The difference in inclination angle between the shift line M and the load HST shift line SA and HMT shift line MA tends to be large.

  A horizontal line L1 passing through the position of the rotational speed “V” on the vertical axis indicates the integrated rotation appearing speed. The rotational speed “V” is the same as “V1”. FIG. 13 is an explanatory diagram showing switching from HST transmission to HMT transmission. As shown in FIGS. 10 and 13, when the control for switching the setting from HST transmission to HMT transmission is performed by setting the output speed of the continuously variable transmission unit to the integrated rotation output speed “V”, During actual travel in which the transmission unit is driven by a load, the output speed of the continuously variable transmission unit as the output speed of the transmission is increased along the HST shift line SA of the load, and the integrated rotation appearing speed [ V], that is, the output speed corresponding to the intersection “X” between the HST shift line SA of the load and the horizontal line L1, the setting is switched from HST transmission to HMT transmission. The output speed of the speed change transmission immediately after this changeover is the output speed “V0” corresponding to the intersection “Y” between the HMT shift line MA of the load and the vertical line passing through the intersection “X”.

  That is, the output speed immediately after the setting switching from the HST transmission to the HMT transmission is reduced from “V” immediately before the switching to “V0” immediately after the switching, and the speed of the decrease is relatively large. It was. As the driving load increases, the inclination angle of the load with respect to the operation position line L of the HST shift line SA becomes smaller, and the difference between the output speed “V” immediately before switching and the output speed “V0” immediately after switching is greater. Become big.

  An object of the present invention is to provide a traveling transmission device for a farm machine capable of suppressing or eliminating a speed change associated with switching from HST transmission to HMT transmission.

According to the first aspect of the present invention, a hydrostatic continuously variable transmission that acts to input and shift a driving force from the engine and shift the output driving force along the HST shift line, and the driving force from the engine. And a shift drive force from the continuously variable transmission unit are input and combined, and a shift having a planetary transmission unit that acts so that the combined drive force to be output is shifted along the HMT shift line by the shift of the continuously variable transmission unit. Equipped with a transmission,
By switching between the HST clutch that sets the HST transmission and the HMT clutch that sets the HMT transmission, the HST transmission that outputs the shift driving force output from the continuously variable transmission unit from the output rotating body to the traveling device, and the planetary transmission unit outputs And configured to switch the transmission to HMT transmission that outputs the combined driving force to the traveling device from the output rotating body,
In a traveling transmission device of an agricultural working machine comprising shift control means for performing shift control of the hydraulic pump that constitutes the continuously variable transmission unit based on a shift command from a shift operation tool and switching and controlling the HST clutch and the HMT clutch,
A swash plate angle sensor for detecting a swash plate angle of the hydraulic pump;
In a speed change state in which the continuously variable transmission portion in HST transmission and no-load drive outputs a speed change driving force corresponding to an integral rotation appearing speed at which the sun gear, carrier and ring gear of the planetary transmission portion appear to rotate integrally. Reference swash plate angle setting means for setting a no-load swash plate angle provided in the hydraulic pump as a set reference swash plate angle,
When the output speed of the continuously variable transmission unit in the HST transmission becomes the integrated rotation actual speed, the swash plate angle of the hydraulic pump is determined based on the detection information by the swash plate angle sensor. By detecting that the swash plate angle is higher than the swash plate angle, the swash plate of the hydraulic pump is returned to the low speed side by a set return angle while maintaining the HST clutch and the HMT clutch in an engaged state. The HST clutch and the HMT clutch are controlled so as to be switched from HST transmission to HMT transmission later.

According to the configuration of the first aspect of the present invention, setting switching from HST transmission to HMT transmission is performed, for example, as shown in FIG.
In other words, when the output speed of the continuously variable transmission that increases along the load HST shift line SA becomes the integrated rotation output speed “V”, the swash plate angle “b” at this time is set to the set reference swash plate angle [ c] is shifted to the high speed side. This is because the load HST shift line SA is displaced from the no-load HST shift line S. Therefore, when the output speed of the continuously variable transmission that increases along the load HST shift line SA reaches the integrated rotation output speed “V”, the shift control means determines that the swash plate angle “b” is the set reference swash plate angle. Detecting that the speed is higher than “c” based on the detection information from the swash plate angle sensor, and returning the swash plate angle of the hydraulic pump to the low speed while maintaining the HST clutch and HMT clutch in the engaged state. When this return amount reaches the set return angle “E”, the HST clutch and the HMT clutch are controlled to be switched from the HST transmission setting to the HMT transmission setting.

  In other words, the output speed of the continuously variable transmission section is changed to the integral rotation appearing speed “V” so that the setting change from the HST transmission to the HMT transmission is performed. Even when the speed becomes “V”, the HST clutch is not immediately switched to the disengaged state, the HMT clutch is switched to the engaged state and the HST clutch is maintained in the engaged state, and the output speed of the continuously variable transmission unit is rotated integrally with the swash plate angle. The operation is to be performed after the set return angle “E” is returned from the swash plate angle “b” when the actual speed becomes “V” to the low speed side, and the HST clutch is switched to the disengaged state. The output speed corresponding to the return target position which is located on the HMT shift line MA of the load and is displaced from the point of intersection “Y” to the high speed side on the load HMT shift line MA at the time of switching to the setting. Speed A is may be performed in a state that the high speed of the output speed from the output speed "V0". Further, the HST clutch and the HMT clutch are engaged while the swash plate angle “b” is returned by the set return angle “E” when the output speed of the continuously variable transmission reaches the integrated rotation output speed “V”. It is possible to cause the output speed to be reduced without causing a decrease in output speed due to the transmission.

  Depending on the setting return angle “E”, the output speed that the speed change transmission will have when the HST clutch is switched to the HMT transmission setting and the HMT transmission line is set to the HMT transmission line MA and the horizontal line L1. And the output speed corresponding to the intersection “G” with the output speed of the same speed as the integrated rotation appearing speed “V”.

  Therefore, it is possible to switch between the setting of HST transmission and HMT transmission, and it is possible to easily switch between forward and backward movements simply by performing forward shift operation and reverse shift operation across the neutral position of the continuously variable transmission. Although it is possible, the shift from the speed range of the HST transmission to the speed range of the HMT transmission can be easily performed in a state where there is no shift shock due to the speed reduction and a sense of incongruity.

  In the second aspect of the invention, the shift control means is configured to calculate and set a calculation HST shift line for HST transmission and load driving based on detection information from the swash plate angle sensor, and to calculate a calculation HMT shift corresponding to the calculation HST shift line. A line is calculated and set, and a swash plate angle for shifting the continuously variable transmission is returned to a shift state in which a shift driving force having a speed corresponding to the integrated rotation appearing speed is output on the calculated HMT shift line. A return angle required to return the swash plate to the return target swash plate angle is set as the set return angle.

  According to the configuration of the second aspect of the present invention, even if an HST shift line having a different inclination angle is generated due to a change in driving load during traveling, a calculation HST shift line and a calculation HMT corresponding to the changing drive load are generated. The transmission line is calculated and set, and based on the calculated HST shift line and the calculated HMT shift line, the output speed that the shift transmission will have at the time of switching to the setting for HMT transmission is the same as the integrated rotation appearing rotation speed An appropriate set return angle for setting the output speed is set, and the setting is switched from the HST transmission to the HMT transmission based on the set return angle, so that the HST transmission is changed to the HMT regardless of changes in the driving load. It is possible to prevent the traveling speed from changing due to the switching of the setting to transmission.

  Therefore, even if there is a change in the driving load during traveling, it is possible to travel lightly by performing a shift that switches from the speed range of the HST transmission to the speed range of the HMT transmission with little or no shift shock or uncomfortable feeling.

It is a side view which shows the whole combine. It is a schematic front view which shows a driving | running | working transmission apparatus. It is a vertical front view which shows the speed change transmission in HMT transmission. It is a vertical front view which shows the transmission in HST transmission. It is explanatory drawing which shows the relationship between the operation state of an HMT clutch and an HST clutch, the operation state of the clutch mechanism of transmission switching, and the transmission state of a transmission gearbox. It is a graph which shows the output characteristic with which the transmission gearbox by no-load drive is provided. It is explanatory drawing which shows the relationship between the value of N / X, and total efficiency. It is explanatory drawing which shows the relationship between the value of N / X and size reduction of a continuously variable transmission part. It is a block diagram which shows a speed change operation apparatus. It is a graph which shows the output characteristic with which a transmission is provided. It is a flowchart of setting switching control. It is explanatory drawing which shows switching of the setting from HST transmission to HMT transmission. It is explanatory drawing which shows the switching of the setting from HST transmission in a comparative example to HMT transmission.

Hereinafter, based on the drawings, a description will be given of the case where the combine is equipped with the transmission device of the agricultural machine according to the present invention.
As shown in FIG. 1, a combine is configured to be self-propelled by a pair of left and right crawler type traveling devices 1, 1, and is equipped with a riding type driving unit 2, and a body frame of the traveling body 3, a cutting part 4 connected to the front part of the machine frame 3, a threshing device 5 provided behind the cutting part 4 on the rear side of the machine body frame 3, and a lateral side of the threshing apparatus 5 on the rear side of the machine body frame 3. And a grain tank 6 arranged and provided on the side, and harvesting rice, wheat and the like.

  That is, the cutting unit 4 includes a cutting unit frame 4a that extends from the front portion of the body frame 3 so as to be able to swing up and down in the forward direction. The weeding tool 4b provided at the front end of the mowing unit 4 moves up and down to a lowering work position where the weeding tool 4b is lowered near the ground, and a rising non-working position where the weeding tool 4b is raised from the ground. When the mowing unit 4 is lowered to the lowering work position and the traveling machine body is run, the mowing unit 4 causes the planted culm to be harvested by the weeding tool 4b to be introduced into the path, and the planting that has been induced and introduced into the path. While raising the standing cereal and raising it by the device 4c, it is cut by the clipper type reaping device 4d, and the chopped cereal is supplied to the threshing device 5 by the supply device 4e. The threshing device 5 sandwiches the stock side of the harvested cereal meal from the supply device 4e by the threshing feed chain 5a and conveys it toward the rear of the machine body, and supplies the tip side of the harvested cereal meal to the handling room (not shown). The threshing process is performed, and the threshing grain is fed into the grain tank 6.

  An engine 8 is provided below a driver seat 2 a provided in the driving unit 2, and driving force output from the engine 8 is transmitted to a pair of left and right by a traveling transmission device 10 including a transmission case 11 provided at the front end of the body frame 3. It is comprised so that it may transmit to the traveling apparatuses 1 and 1.

  FIG. 2 is a front view showing a schematic structure of the traveling transmission device 10. As shown in this figure, the traveling transmission device 10 provides engine driving force from the output shaft 8a of the engine 8 on the side of the upper end of the transmission case 11 via the transmission mechanism 12 provided with the transmission belt 12a. To the left side of the pair of left and right steering clutch mechanisms 14, 14 included in the traveling mission 13 by inputting the output of the transmission transmission 20 to the traveling mission 13 built in the transmission case 11. Is transmitted from the steering clutch mechanism 14 to the drive shaft 1a of the left traveling device 1, and is transmitted from the right steering clutch mechanism 14 to the drive shaft 1a of the right traveling device 1.

  The traveling transmission device 10 includes a cutting mission 15 incorporated in the transmission case 11, and the output of the transmission 20 is input to the cutting mission 15 and transmitted from the cutting output shaft 16 to the drive shaft 4 f of the cutting unit 4.

The transmission 20 will be described.
As shown in FIGS. 3 and 4, the transmission 20 is connected to the planetary transmission unit 20 </ b> A having a transmission case 21 having a lateral side connected to the upper end side of the transmission case 11, and to the transmission case 11 of the transmission case 21. And a hydrostatic continuously variable transmission 30 having a casing 31 connected to a lateral side opposite to the side to be operated.

  The transmission case 21 houses a main case portion 21 a that houses the planetary transmission unit 40 and the transmission mechanism 50, a coupling portion of the input shaft 22, the transmission shaft 23, and the continuously variable transmission unit 30, and the transmission case 21 and the casing 31. A connection case portion 21b for connecting the port block 34 is provided. The transmission case 21 is connected to the transmission case 11 at a bulging portion 21c that is bulged outwardly on the lateral side of the lower side surface where the output rotating body 24 of the main case portion 21a is located. The size of the connecting case portion 21b in the vertical direction of the traveling machine body is smaller than the size of the main case portion 21a in the vertical direction of the traveling machine body. The main case portion 21a is formed so that the longitudinal cross-sectional shape when viewed in the longitudinal direction of the fuselage is a longitudinally long shape, and the casing 31 is formed such that the longitudinal sectional shape when viewed in the longitudinal direction of the aircraft is longitudinally elongated. While the section 20A and the continuously variable transmission section 30 are arranged in the lateral direction of the vehicle body, the lateral width of the entire transmission gearbox 20 is reduced, and the transmission gearbox 20 does not protrude laterally in the lateral direction of the traveling vehicle body. It is connected to the lateral side of the mission case 11 in a compact state. Further, the lower side surface of the casing 31 is formed with an inclined surface 31A that is inclined toward the inner side of the machine body at the lower end side, and a bulging portion 31B that supports the bearing of the motor shaft 33a is formed on the inclined surface 31A. Is being made more compact. In addition, an oil filter 20F is disposed on the upper surface of the casing 31 so as to avoid protrusion of the oil filter 20F to the lateral outer side, thereby achieving further compactness.

  The planetary transmission unit 20A includes a laterally-facing input shaft 22 that is rotatably supported on the upper end side of the transmission case 21, and a transmission that is rotatably supported in parallel or substantially parallel to the input shaft 22 on the lower end side of the transmission case 21. A shaft 23 and a rotary shaft type output rotor 24; a planetary transmission unit 40 supported by the transmission shaft 23; and a transmission mechanism 50 provided across the input shaft 22 and the carrier 41 of the planetary transmission unit 40. Yes.

  The input shaft 22 is arranged so as to be arranged coaxially with the pump shaft 32 a of the continuously variable transmission 30. The input shaft 22 is configured to be coupled to the output shaft 8a of the engine 8 via the transmission mechanism 12 on the side projecting laterally outward from the transmission case 21, and the joint on the opposite side to the side coupled to the engine 8 It is connected to the pump shaft 32a of the continuously variable transmission unit 30 via 22a so as to be rotatable together. The engine driving force is input via the transmission mechanism 12, and the hydraulic pressure of the continuously variable transmission unit 30 is driven by the engine driving force. The pump 32 is driven.

  The output rotator 24 is arranged on the same side as the side where the engine coupling side of the input shaft 22 is located with respect to the continuously variable transmission 30 so as to be aligned coaxially with the motor shaft 33a of the continuously variable transmission 30. The output rotator 24 is configured to be interlocked with the input portion of the traveling mission 13 on the side projecting laterally outward from the transmission case 21, and the driving force from the planetary transmission unit 40 and the continuously variable transmission unit 30 is used as the traveling mission. 13 to the pair of left and right traveling devices 1, 1.

  The continuously variable transmission unit 30 includes a hydraulic pump 32 in which a pump shaft 32a is rotatably supported on the upper end side of the casing 31, and a hydraulic motor 33 in which a motor shaft 33a is rotatably supported on the lower end side of the casing 31. It is configured with. The hydraulic pump 32 is constituted by a variable displacement axial plunger pump, and the hydraulic motor 33 is constituted by an axial plunger motor. The hydraulic motor 33 is driven by pressure oil that is discharged by the hydraulic pump 32 and supplied through an oil passage formed inside the port block 34. The continuously variable transmission 30 is supplied with supplementary hydraulic fluid by a charge pump 90 provided at the end of the pump shaft 32a. The charge pump 90 includes a rotor 90a that is attached to the pump shaft 32a so as to be integrally rotatable, and a pump casing 90b that is detachably connected to the casing 31.

  Therefore, the continuously variable transmission unit 30 is switched to the forward transmission state, the reverse transmission state, and the neutral state by performing an angle changing operation of the swash plate 32b included in the hydraulic pump 32. When the continuously variable transmission unit 30 is switched to the forward drive state, the engine drive force transmitted from the input shaft 22 to the pump shaft 32a is converted into the forward drive force and output from the motor shaft 33a to enter the reverse drive state. When the switching operation is performed, the engine driving force transmitted from the input shaft 22 to the pump shaft 32a is converted into a reverse driving force and output from the motor shaft 33a, and the engine driving force in both the forward transmission state and the reverse transmission state. Is output in a stepless manner. The continuously variable transmission unit 30 stops the output from the motor shaft 33a when switched to the neutral state.

  The planetary transmission unit 40 is disposed on the same side as the side where the engine coupling side of the input shaft 22 is positioned with respect to the continuously variable transmission unit 30 and is positioned between the motor shaft 33 a and the output rotating body 24. The planetary transmission unit 40 is configured to freely rotate a sun gear 42 supported by the transmission shaft 23, a plurality of planetary gears 43 that mesh with the sun gear 42, a ring gear 44 that meshes with each planetary gear 43, and a plurality of planetary gears 43. And a carrier 41 to be supported. The carrier 41 includes an arm portion 41a that rotatably supports the planetary gear 43 at the extended end portion, and a cylindrical shaft portion 41b to which the base end sides of the plurality of arm portions 41a are connected. The transmission shaft 23 is rotatably supported via a bearing.

  The transmission shaft 23 and the motor shaft 33a are connected so as to be integrally rotatable via a joint 23a, and the transmission shaft 23 and the sun gear 42 are connected so as to be integrally rotatable via a spline structure. The shaft 33a is interlocked with the shaft 33a so as to be integrally rotatable.

  The ring gear 44 and the output rotating body 24 are integrally rotatable by an annular planetary interlocking body 26 and an annular output side interlocking body 27 that are externally fitted to the transmission shaft 23 so as to be relatively rotatable side by side in the axial direction. It is linked to. That is, the planetary interlocking body 26 includes a plurality of engagement arm portions 26 a that extend radially and integrally from the outer peripheral portion of the planetary interlocking body 26. The plurality of engagement arm portions 26 a are engaged with a plurality of locations of the ring gear 44, and the planetary interlocking body 26 is interlocked with the ring gear 44 so as to be integrally rotatable. The output-side interlocking body 27 is engaged with the planetary-side interlocking body 26 so as to be integrally rotatable with an engaging claw 27a, and is integrally engaged with the output rotating body 24 with a spline structure. The interlocking body 26 and the output rotating body 24 are connected so as to be rotatable together. The planetary interlocking body 26 is supported on the transmission shaft 23 through a bearing so as to be relatively rotatable. The output side interlocking body 27 is rotatably supported by the transmission case 21 via a bearing.

  The transmission mechanism 50 is a transmission gear 52 that is supported on the input shaft 22 through a needle bearing so as to be relatively rotatable while meshing with an input gear 41c of the carrier 41 that is provided rotatably on the cylindrical shaft portion 41b of the carrier 41. And an HMT clutch 55 provided across the transmission gear 52 and the input shaft 22.

  The HMT clutch 55 includes a clutch body 56 that is supported by the input shaft 22 so as to be integrally rotatable and slidable, and a clutch main body 57 that is provided across one end side of the clutch body 56 and the lateral side portion of the transmission gear 52. It is prepared. The clutch body 56 is slid and operated by a hydraulic piston 58 fitted in the end of the clutch body 56. The clutch body 57 is configured as a meshing clutch so that the meshing claw provided on the clutch body 56 and the meshing claw provided on the transmission gear 52 are engaged and disengaged to switch between the on state and the off state.

  When the clutch body 57 is switched to the engaged state, the HMT clutch 55 is switched to the input state so as to interlock the input shaft 22 and the transmission gear 52 so as to be integrally rotatable, and the HMT clutch 55 is switched to the carrier 41 of the planetary transmission unit 40. The HMT transmission is set so as to interlock with the input shaft 22.

  When the clutch main body 57 is switched to the disengaged state, the HMT clutch 55 is switched to the disengaged state so as to disconnect the input shaft 22 and the transmission gear 52 from each other, and the carrier 41 of the planetary transmission unit 40 and the input shaft 22 are switched. The state where the setting of HMT transmission is canceled so as to cut off the interlocking of the motor is brought about.

  Accordingly, the planetary transmission unit 40 is switched from the portion located between the engine connecting side of the input shaft 22 and the continuously variable transmission unit connecting side to the input shaft when the HMT clutch 55 is switched to the state in which the HMT transmission is set. The driving force 22 is input to the carrier 41 through the transmission mechanism 50. The planetary transmission unit 40 is switched to the state in which the HMT clutch 55 has released the setting of the HMT transmission, so that the interlocking of the carrier 41 with the input shaft 22 is cut off.

  An HST clutch 60 including a clutch body 61 fitted on the transmission shaft 23 is provided across the sun gear 42 of the planetary transmission unit 40 and the planetary side interlocking body 26.

  The clutch body 61 is slidably operated toward the sun gear 42 against the energizing spring 62 when pressure oil is supplied to an oil chamber formed on the inner peripheral side of the clutch body 61, so that the clutch body 61 is in the cut position. When the pressure oil is discharged from the oil chamber, the urging spring 62 is slid toward the planetary interlocking body 26 to switch to the entry position. When the clutch body 61 is switched to the entering position, the clutch pawl 61 a provided on the clutch body 61 and the clutch pawl provided on the planetary interlocking body 26 are engaged with each other, so that the clutch body 61 is integrated with the planetary interlocking body 26. Connect freely. The clutch body 61 is slid while maintaining a state in which the clutch body 61 is engaged with the sun gear 42 by the engaging claws 61b so as to be integrally rotatable. When the clutch body 61 is switched to the disengagement position, the clutch pawl 61a is disengaged from the planetary interlocking body 26.

  Therefore, the HST clutch 60 rotates the motor shaft 33a integrally with the output rotating body 24 by interlocking the sun gear 42 and the planetary interlocking body 26 so that the clutch body 61 is switched to the engaged position. The HST transmission is set so as to enable the output from the output rotating body 24 by the continuously variable transmission unit 30 to be interlocked freely. In the HST clutch 60, when the HST transmission is set, the sun gear 42 and the transmission shaft 23 are interlocked so as to be integrally rotatable, and the ring gear 44 and the planetary side interlocking body 26 are interlocked so as to be integrally rotatable. The sun gear 42, the carrier 41, and the ring gear 44 can rotate integrally with the motor shaft 33a so that the rotation does not occur.

  The HST clutch 60 switches the sun gear 42 and the output rotating body 24 of the planetary transmission unit 40 between the interlocking on state and the interlocking off state while maintaining the ring gear 44 and the output rotating body 24 of the planetary transmission unit 40 in an interlocking state.

  When the clutch body 61 is switched to the disengagement position, the HST clutch 60 stops the interlocking of the sun gear 42 and the planetary side interlocking body 26, disconnects the interlocking of the motor shaft 33a with the output rotating body 24, and planetary transmission. The ring gear 44 of the unit 40 and the output rotator 24 are linked together so that they can rotate together, and the HST transmission is set so that the combined driving force of the planetary transmission unit 40 can be output from the output rotator 24. It will be in a released state.

  Therefore, the planetary transmission unit 40 is switched to the state in which the HMT clutch 55 is set to HST transmission, and the HST clutch 60 is switched to the state in which the setting of the HST transmission is released to be transmitted to the input shaft 22 from the engine. The driving force thus generated is input to the carrier 41 via the transmission mechanism 50, and the shift driving force output from the motor shaft 33a of the continuously variable transmission unit 30 is input to the sun gear 42 via the transmission shaft 23 to drive from the engine. The combined driving force is generated by combining the force and the speed change driving force from the continuously variable transmission unit 30, and the generated combined driving force is output from the ring gear 44 via the planetary side interlocking body 26 and the output side interlocking body 27. Output to the body 24.

  That is, a transmission setting clutch mechanism 70 is provided that includes the HMT clutch 55 and the HST clutch 60 and switches the transmission 20 to be set between HMT transmission and HST transmission.

  FIG. 5 is an explanatory diagram showing the relationship between the operating state of the HMT clutch 55 and the HST clutch 60, the operating state of the transmission-set clutch mechanism 70, and the transmission state of the transmission 20. “Disconnected” shown in FIG. 5 indicates the disengaged state of the HMT clutch 55 and the HST clutch 60, and “On” indicates the engaged state of the HMT clutch 55 and the HST clutch 60. As shown in this figure, when the HMT clutch 55 is switched to the disengaged state and the HST clutch 60 is switched to the engaged state, the transmission setting clutch mechanism 70 enters the HST transmission setting state, and the transmission 20 Set HST transmission to. When the HMT clutch 55 is switched to the engaged state and the HST clutch 60 is switched to the disengaged state, the transmission setting clutch mechanism 70 enters the HMT transmission setting state and sets the HMT transmission in the transmission 20.

  FIG. 3 is a longitudinal front view showing the transmission 20 with HMT transmission. As shown in this figure, in the transmission 20, when the HMT clutch 55 is switched to the engaged state and the HST clutch 60 is switched to the disconnected state, the driving force of the input shaft 22 (the driving force from the engine 8). ) Is input to the carrier 41 of the planetary transmission unit 40 via the transmission mechanism 50, and the continuously variable transmission unit 30 shifts the driving force input from the input shaft 22 and outputs the transmission driving force output from the motor shaft 33a to the planetary transmission unit. 40 is input to the sun gear 42, and the planetary transmission unit 40 combines the driving force from the engine 8 input from the input shaft 22 by the planetary transmission unit 40 and the transmission driving force input from the continuously variable transmission unit 30 by the planetary transmission unit 40. , And the combined driving force output from the ring gear 44 by the planetary transmission unit 40 is transmitted to the end of the output rotating body 24 via the planetary side interlocking body 26 and the output side interlocking body 27 to be output to the output rotating body 24. To output La running mission 13.

  FIG. 4 is a longitudinal front view showing the transmission 20 with HST transmission. As shown in this figure, in the transmission 20, when the HMT clutch 55 is switched to the disengaged state and the HST clutch 60 is switched to the engaged state, the continuously variable transmission 30 receives the drive input from the input shaft 22. The speed change driving force output from the motor shaft 33a by shifting the force is transmitted to the end of the output rotating body 24 via the transmission shaft 23, the HST clutch 60, the planetary side interlocking body 26 and the output side interlocking body 27 for output. Output from the rotating body 24 to the traveling mission 13.

  When the HST transmission is set, the transmission setting clutch mechanism 70 is in a state where transmission from the input shaft 22 to the carrier 41 of the planetary transmission unit 40 is cut off, and the sun gear 42 is connected to the motor shaft 33 a via the transmission shaft 23. Since the ring gear 44 is in a state of being linked to the motor shaft 33a via the planetary side linkage body 26, the clutch body 61, the sun gear 42, and the transmission shaft 23, the ring gear 44 is linked to the motor shaft 33a. The sun gear 42, the carrier 41, and the ring gear 44 of the planetary transmission unit 40 are rotated integrally with the motor shaft 33a, and the transmission 20 does not cause the planetary gear 43 to rotate in HST transmission, that is, the sun gear 42 and the planetary gear. Without causing relative rotation of the gear 43 and relative rotation of the planetary gear 43 and the ring gear 44, the motor shaft 33a of the continuously variable transmission unit 30 can be The transmitted to the output rotor 24.

  FIG. 6 is a graph (speed diagram) showing the output characteristics of the variable speed transmission 20 with no-load driving that is driven without applying a traveling load as a driving load to the output rotating body 24. The vertical axis of this graph is a speed line indicating the rotational speed of the output rotating body 24. The horizontal axis of this graph passes through the position where the rotational speed of the vertical axis is zero “0”, and is an operation position line L indicating the swash plate position of the hydraulic pump 32 in the continuously variable transmission 30. “N” in the operation position line L is a neutral position of the swash plate 32b that brings the continuously variable transmission 30 to a neutral state. “A” on the operation position line L is a set forward high speed position set as the fastest speed position on the forward side of the swash plate 32b for switching between setting of HST transmission and HMT transmission in no-load drive. “+ Max” of the operation position line L is the actual forward maximum high-speed position of the continuously variable transmission 30, and when the continuously variable transmission 30 is shifted to the operation limit on the forward high speed side, the swash plate 32 b of the hydraulic pump 32. Is the swash plate angle position actually generated. The set forward high speed position “a” is an actual forward movement in order to maintain speed continuity at the point where the HST transmission and the HMT transmission are switched in a simple configuration in which the rotation of the motor shaft 33a is input to the planetary terminal without increasing or decreasing. It is set to a position before the maximum speed position “+ max”. “−max” of the operation position line L is a set reverse high speed position set as the maximum reverse speed position on the reverse side of the swash plate 32b operated by the shift control. The set reverse high speed position “−max” is set to the same position as the swash plate angular position actually generated in the swash plate 32b of the hydraulic pump 32 when the continuously variable transmission 30 is changed to the reverse high speed operation limit. It is.

  The shift line S shown in FIG. 6 indicates the rotational speed of the output rotating body 24 when the transmission transmission 20 is shifted by HST transmission in a state where the engine 8 is accelerator-set so as to output a set constant speed driving force. No-load HST shift line (hereinafter abbreviated as HST shift line S) showing the change of the shift line M, and the shift line M is in an accelerator-set state so that the engine 8 outputs a set driving force at a constant speed. 2 is an unloaded HMT shift line (hereinafter abbreviated as HMT shift line M) indicating a change in the rotational speed of the output rotating body 24 when the transmission 20 is shifted by HMT transmission.

  As shown in FIG. 6, in the state where the HMT clutch 55 is controlled to be switched off, the HST clutch 60 is controlled to be switched on and the HST transmission is set, and the setting of the HST transmission is maintained, the continuously variable transmission unit 30 is shifted from the neutral position “n” toward the set forward high speed position “a”, so that the rotational speed of the output rotating body 24 moves from zero “0” to the forward side along the forward travel area SF of the HST shift line S. When the continuously variable transmission 30 reaches the set forward high speed position “a”, the rotational speed of the output rotating body 24 becomes the first forward intermediate speed “V1”.

  When the continuously variable transmission 30 reaches the set forward high speed position “a”, the HMT clutch 55 is controlled to be switched from the disengaged state to the engaged state, and the HST clutch 60 is controlled to be switched from the engaged state to the disengaged state to change to HST transmission. In a state where the HMT transmission is set and the setting of the HMT transmission is maintained, the continuously variable transmission unit 30 is shifted from the set forward high speed position “a” to the neutral position “n”, thereby When the rotational speed increases steplessly from the first forward intermediate speed “V1” along the low speed region ML of the HMT shift line M and the continuously variable transmission 30 reaches the neutral position “n”, the output rotation The rotation speed of the body 24 becomes the second forward intermediate speed “V2”. In the state where the setting of the HMT transmission is maintained, the rotation speed of the output rotating body 24 is set to the second speed by changing the speed of the continuously variable transmission 30 from the neutral position “n” toward the set reverse high speed position “−max”. When the continuously variable transmission section 30 reaches the set reverse high speed position “−max”, the output rotating body 24 increases steplessly along the high speed range MH of the HMT shift line M from the forward intermediate speed “V2”. Is the maximum forward speed “V3”.

  In the state where the setting of the HST transmission is maintained, the rotation speed of the output rotating body 24 is reduced to zero by operating the continuously variable transmission 30 from the neutral position “n” toward the set reverse high speed position “−max”. When the continuously variable transmission unit 30 reaches the set reverse high speed position “−max”, the speed of the output rotating body 24 rotates. The speed becomes the reverse maximum speed “VR”.

  In a shift state corresponding to the low speed range ML of the HMT shift line M so that the driving force output in the shift state corresponding to the high speed range MH of the HMT shift line M becomes a driving force having a rotational speed suitable for traveling. Further, the driving force input from the engine 8 is adopted while adopting the continuously variable transmission unit 30 in which the discharge capacity of the hydraulic pump 32 is as small as possible so that the output driving force becomes a driving force having a rotation speed suitable for work travel. The inclination angle B of the HMT shift line M with respect to the operation position line L is set as follows so that the loss associated with the shift can be reduced as much as possible to obtain the driving force after the shift.

  The shift line extension line ME shown in FIG. 6 is obtained by extending the HMT shift line M toward the operation position line L, and the position “P” on the operation position line L indicates the shift line extension line ME and the operation position line. This is the intersection position where L intersects. It is assumed that the swash plate 32b of the hydraulic pump 32 of the continuously variable transmission unit 30 can be tilted to the crossing position “P” beyond the actual forward maximum high-speed position “+ max” as the maximum forward tilt position where the tilting can be actually performed. The value of the virtual inclination angle that the swash plate 32b has when the tilt operation is performed to the intersection position “P” is “N”, and the continuously variable transmission unit 30 that has been shifted to the actual forward maximum high speed position “+ max”. When the value of the actual maximum swash plate angle actually generated in the hydraulic pump 32 is “X”, the HMT shift line M is set to an inclination angle corresponding to N being twice X (N / X = 2.0). An inclination angle B with respect to the operation position line L is set. The setting of N / X = 2.0 depends on the setting of the discharge capacity of the hydraulic pump 32 and the setting of the gear transmission ratio in the planetary transmission unit 40 and the mechanical transmission unit other than the planetary transmission unit 40.

  The inclination angle B of the HMT shift line M with respect to the operation position line L is the rotational speed of the output rotating body 24 at the first forward intermediate speed “V1” when the rotational speed of the output rotating body 24 at the maximum forward speed “V3”. The inclination angle is set to be twice or more.

The setting of N / X = 2.0 is based on the ground explained below.
When the output rotation of the continuously variable transmission unit 30 is zero and the output rotational speed is V2, all power is output without passing through the continuously variable transmission unit 30. At the position (P) of the virtual swash plate angle at which the output rotation is zero, the power at the output rotation speed V2 is returned to the drive side through the continuously variable transmission 30 and the output becomes zero. That is, the mechanical transmission force that does not pass through continuously variable transmission 30 is balanced with the power of continuously variable transmission 30 (hereinafter referred to as HST power). Actually, since the position (P) of the virtual swash plate angle is a virtual position, considering the actual maximum inclination angle X = 1 at the actual forward maximum speed position “+ max” of the continuously variable transmission unit 30, the HST power is Since the rotational speed is 1 / N, it is 1 / N times the mechanical transmission power that does not pass through the continuously variable transmission 30.

If the mechanical efficiency is KM with mechanical transmission power and KH with power passing through the continuously variable transmission 30, the output power is constant mechanical power ± HST power, and the total efficiency exhibited by the transmission 20 is:
When the continuously variable transmission 30 is in the neutral position “n”, (1 + 0 × 1 / N) / (1 / KM + 0 × 1 / N / KH) = KM is calculated,
If the continuously variable transmission 30 is at the set reverse high speed position “−max”, it is calculated as (1 + 1 / N) / (1 / KM + 1 / N / KH) = KM · KH (N + 1) / (KM + KH · N)
When the continuously variable transmission 30 is at the actual forward maximum high speed position “+ max”, (1-1 / N) / (1 / KM−1 / N · KH) = KM (N−1) / (N−KM · KH) and the higher the efficiency, the higher the N is.

  FIG. 7 is an explanatory diagram showing the relationship between the total efficiency and the shift position when the value of N / X is changed. Here, KM = 0.95, KH = 0.7, N / X = 1.0, N / X = 2.0, and N / X = 3.0. Is shown.

  The horizontal axis shown in FIG. 7 indicates the speed change position, and the forward reverse speed position is set for the output rotational speed when the continuously variable transmission 30 is changed to an arbitrary speed change position in the forward side in HST transmission and in the HMT transmission. The ratio of the output rotation speed when the gear is shifted to “−max” is the shift position on the horizontal axis. That is, assuming that the rotational speed of the driving force output when the continuously variable transmission 30 is shifted to an arbitrary shift position in the forward side in the HST transmission and the HMT transmission is Vn / V3, the horizontal shift position is Vn / V3. It is said. A vertical line D shown in FIG. 7 is a line indicating the highest speed of HST transmission when N / X = 2.0, and indicates Vn / V3 = 0.33 (between 0.2 and 0.4). is there. A vertical line E shown in FIG. 7 is a line indicating HMT transmission when N / X = 2.0 and the speed of the swash plate neutral of the hydraulic pump 32. Vn / V3 = 0.67 (0.6 and 0) .8). Therefore, the set forward high speed position “a” of the continuously variable transmission unit 30 is a position between 0.2 and 0.4 on the horizontal axis, and the neutral position “n” of the continuously variable transmission unit 30 is on the horizontal axis. Between 0.6 and 0.8.

  The efficiency line K shown in FIG. 7 indicates the total efficiency of the continuously variable transmission unit 30. The efficiency line K1 shown in FIG. 7 shows the total efficiency estimated as N / X = 1.0, and the efficiency line K2 shows the total efficiency estimated as N / X = 2.0. The efficiency line K3 shows the total efficiency estimated as N / X = 3.0.

  Between the vertical line D and the vertical line E, the total efficiency is good when N / X = 1.0, but since the output on the high speed side is large, the loss power is large and there is a small efficiency difference. It cannot be ignored. When the loss power multiplied by the loss rate and the output power is examined, N / X = 1.8 is a minimum value. The optimum value as the loss power is wide on the side where N / X is small across N / X = 1.8, but N / X = 2.0 is the optimum value for downsizing of the continuously variable transmission unit 30. If this balance is taken and N / X = about 1.5 to 2.5, high efficiency in the high speed range is realized and the size of the continuously variable transmission 30 can be reduced to about 38%. Is done. At this time, the output rotation of the planetary transmission unit 40 in the HMT transmission can also be designed in a realistic region not exceeding 10,000 rpm. When the transmission transmission 20 unit is independent, the influence of the torque cross due to the seal of the output unit or the like can be reduced if the speed is reduced to about the number of revolutions from the drive source. This is also easy to configure realistically. In order to employ the simple transmission setting clutch mechanism 70 as described above to achieve high efficiency and downsizing of the continuously variable transmission unit 30, a setting of N / X = 1.5 to 2.5 is advantageous.

  FIG. 8 is an explanatory diagram showing the relationship between the value of N / X and the size reduction of the continuously variable transmission unit 30. The horizontal axis in FIG. 8 indicates the value of N / X. A line F shown in FIG. 8 indicates the ratio “W” of the HST power (1 / N) to the total power (1 + 1 / N). The larger the ratio “W”, the larger the continuously variable transmission unit 30 is required in which the discharge capacity of the hydraulic pump 32 is increased.

  When the driving force over a predetermined shift range is obtained by the output from the planetary transmission unit 40, the continuously variable transmission unit 30 can be made smaller than the case where it is obtained by the output from the continuously variable transmission unit 30, as shown in FIG. Line G shows the relationship between the value of N / X and the degree to which the continuously variable transmission unit 30 can be miniaturized.

  That is, if the point at which the HST transmission and the HMT transmission are switched is the actual maximum tilt position “+ max”, the maximum speed in the HMT transmission (forward maximum speed “V3”) is similar to the maximum speed in the HST transmission. (N + 1) / (N-1) = Z. Z becomes 5.0 when N / X = 1.5, becomes 3.0 when N / X = 2.0, becomes 2.3 when N / X = 2.5, and N / X = 3 If it is .0, it becomes 2.0. The value indicated by the vertical axis in FIG. 8 is a value of 1 / Z.

  As the value of Z increases, the speed change range that can be obtained by HMT transmission becomes wider, the speed change range by HST transmission can be made smaller, and the continuously variable transmission 30 can be made more compact. However, if the discharge capacity of the hydraulic pump 32 is made too small, a driving trouble such as the relief circuit opening and operating will occur. Therefore, by adopting N / X = 2.0 that expresses the intersection between the line F and the line G, the forward maximum speed “V3” and the second forward intermediate speed “V2” by HMT transmission are moved or worked. Thus, it is possible to obtain the speed change transmission 20 capable of speed change transmission while avoiding the occurrence of drive troubles in the stepless speed change portion 30 while reducing the size of the stepless speed change portion 30 while maintaining the required speed.

  FIG. 10 shows the output characteristics of the transmission 20 with no-load drive that is driven without applying a traveling load as a driving load to the output rotating body 24, and the traveling load as a driving load is applied to the output rotating body 24. It is a graph (speed diagram) which shows the output characteristic with which the speed change transmission 20 by the load drive driven in a state is equipped. FIG. 12 is an explanatory diagram showing switching of setting from HST transmission to HMT transmission. The vertical and horizontal axes in FIGS. 10 and 12 are the same as the vertical and horizontal axes of the graph shown in FIG. “N”, “a”, and “−max” described in FIGS. 10 and 12 are the same as “n”, “a”, and “−max” described in the graph of FIG.

  The shift line SA shown in FIG. 10 is in a state where the engine 8 is accelerator-set so as to output a driving force at a set constant speed, and in the state where a traveling load as a set value driving load is applied to the output rotating body 24. Furthermore, it is a load HST shift line (hereinafter abbreviated as HST shift line SA) indicating a change in the rotational speed of the output rotating body 24 of the transmission 20 driven by the setting of the HST transmission. The shift line MA shown in FIG. 10 is in a state where the engine 8 is accelerator-set so as to output a driving force at a set constant speed, and in a state where a traveling load as a set value driving load is applied to the output rotating body 24. Further, it is a load HMT shift line (hereinafter abbreviated as HMT shift line MA) indicating a change in the rotational speed of the output rotating body 24 of the transmission transmission 20 driven by the setting of the HMT transmission. Since the HST shift line SA is in a state where a driving load is applied to the swash plate 32b, the inclination angle of the HST shift line SA with respect to the operation position line L is the inclination angle of the HST shift line S with respect to the operation position line L. Become smaller. Since the HMT shift line MA is in a state in which a driving load is applied to the swash plate 32b, the low speed side of the HMT shift line MA is shifted to the low speed side with respect to the HMT shift line M.

  A horizontal line L1 shown in FIG. 10 indicates that the clutch mechanism 70 for switching the setting from the HST transmission to the HMT transmission is provided in the motor shaft 33a when switching the setting from the HST transmission to the HMT transmission. A motor that causes the planetary transmission unit 40 to manifest the integral rotation of the sun gear 42, the carrier 41, and the ring gear 44 when the switching is completed and the driving force from the engine 8 is transmitted to the planetary transmission unit 40. This shows the rotation speed of the shaft 33a (integrated rotation appearance speed “V”). The rotation speed of the motor shaft 33 a is the same as the rotation speed “V” of the output rotating body 24. The continuously variable transmission unit 30 in HST transmission and no-load drive has an integrated rotation appearing speed “V” by operating the swash plate 32b of the hydraulic pump 32 to the set forward high speed position “a”.

  FIG. 9 is a block diagram showing a speed change operating device 71 for speed changing the speed change transmission 20. As shown in this figure, the speed change operation device 71 includes a control device 72 linked to the speed change operation portion 30 a of the continuously variable transmission portion 30, the operation portions 55 a and 60 a of the HMT clutch 55 and the HST clutch 60, and a control device 72. The shift operation tool 77, the engine speed sensor 74, the swash plate angle sensor 75, the output speed sensor 76 for the transmission, and the output speed sensor 79 for the transmission unit are provided.

  The speed change operation unit 30 a is configured by an electric actuator or a hydraulic actuator that performs an angle change operation of the swash plate 32 b of the hydraulic pump 32 in the continuously variable transmission unit 30. The operation portion 55a of the HMT clutch 55 is configured by an operation valve connected to the hydraulic piston 58 via an operation oil passage formed inside the input shaft 22, and the clutch body 56 is operated by operating the hydraulic piston 58. The HMT clutch 55 is switched by performing a sliding operation. The operation portion 60a of the HST clutch 60 is configured by an operation valve connected to the oil chamber of the clutch body 61 via an operation oil passage formed inside the transmission shaft 23, and the operation of the clutch body 61 with respect to the oil chamber is performed. By supplying and discharging oil, the clutch body 61 is slid and the HST clutch 60 is switched.

  The speed change operating tool 77 is constituted by a speed change lever provided in the operating section 2 so as to be swingable in the longitudinal direction of the traveling machine body. The forward operation area extends from the neutral position “77N” and the neutral position [77N] to the front side of the machine body. The swing operation is performed in “77F” and a reverse operation region “77R” extending from the neutral position “77N” to the rear side of the machine body. The shift operation tool 77 is linked to the control device 72 via a shift detection sensor 73 that detects an operation position of the shift operation tool 77. The shift detection sensor 73 is constituted by a rotary potentiometer in which a rotation operation shaft is interlocked with the shift operation tool 77. The shift operation tool 77 is operated to swing, thereby operating the shift detection sensor 73 to change the speed. A shift command is output from the detection sensor 73 to the control device 72 as an electric signal.

  The engine speed sensor 74 detects the speed of the engine 8 and outputs the detection result to the control device 72. The swash plate angle sensor 75 detects the swash plate angle of the hydraulic pump 32 of the continuously variable transmission 30 and outputs the detection result to the control device 72. The output rotational speed sensor 76 for the transmission detects the rotational speed of the output rotating body 24 as the output rotational speed of the transmission gear 20 and outputs the detection result to the control device 72. The output rotation speed sensor 79 for the transmission unit detects the rotation number of the motor shaft 33 a as the output rotation number of the continuously variable transmission unit 30, and outputs the detection result to the control device 72.

  The control device 72 is configured using a microcomputer, and includes a shift control means 78 and a reference swash plate angle setting means 80.

  The reference swash plate angle setting means 80 is configured by a storage unit provided in the control device 72. The reference swash plate angle setting means 80 is set and inputted in advance with a set reference swash plate angle “c” used when switching control of setting from HST transmission to HMT transmission is performed. With respect to the set reference swash plate angle “c”, the HST transmission and no-load drive continuously variable transmission unit 30 is shifted to a shift state in which a shift drive force having a speed corresponding to the integrated rotation actual speed “V” is output. In this state, a swash plate angle provided in the swash plate 32b which is operated at the set forward high speed position “a”, which is an unloaded swash plate angle provided in the hydraulic pump 32, is set.

  The shift control means 78 detects the rotation speed of the accelerator-set engine 8 based on the information detected by the engine rotation speed sensor 74, the detection result, the shift command from the shift operation tool 77, and the swash plate angle sensor. 75. Shift control of the hydraulic pump 32 is performed based on the detection information by the output rotation speed sensor 76 for the transmission and the output rotation speed sensor 79 for the transmission and the setting information by the reference swash plate angle setting means 80, and the clutch. The HST clutch 60 and the HMT clutch 55 of the mechanism 70 are switched and controlled.

  FIG. 11 is a flowchart showing setting switching control for switching the setting from HST transmission to HMT transmission. As shown in this figure, the shift control means 78 calculates and sets a return target swash plate angle “e” corresponding to the set return angle “E” as will be described later. The shift control means 78 compares the detected rotation speed “Vk” detected by the output rotation speed sensor 79 for the shift section with the integrated rotation appearing speed “V” inputted in advance to the storage section, so that the speed change in the HST transmission can be achieved. It is detected whether or not the output speed of the step transmission unit 30 has reached the integral rotation appearing speed “V”. By comparing the plate angle “c”, it is detected whether or not the swash plate angle of the hydraulic pump 32 is higher than the set reference swash plate angle “c”.

  The shift control means 78 detects that the output speed of the continuously variable transmission 30 has reached the integral rotation output speed “V”, and the swash plate angle of the hydraulic pump 32 is higher than the set reference swash plate angle “c”. Is detected, the HST clutch 60 is kept in the engaged state, and the HMT clutch 55 is switched to the engaged state and maintained in the engaged state, while the transmission operation unit 30a of the continuously variable transmission unit 30 is predetermined. Swash plate 32b is returned to the low speed side, and the swash plate angle "SK" detected by the swash plate angle sensor 75 is compared with the return target swash plate angle "e". Detects whether the set return angle “E” has returned.

  When the shift control means 78 detects that the swash plate 32b has returned by the set return angle “E”, the shift control means 78 controls to switch the HST clutch 60 to the disengaged state, and keeps the HMT clutch 55 in the engaged state, thereby disengaging the HMT clutch 55. In the on state, the HST clutch 60 is controlled to be switched off.

  Accordingly, the accelerator 8 is set to output the driving force at a constant rotational speed, and the speed changer 77 is operated over the reverse operation range [77R], the neutral position “77N”, and the forward operation range [77F]. As a result, the shift control means 78 performs control to switch the transmission gear 20 by switching between HST transmission and HMT transmission and shift control of the hydraulic pump 32, and the traveling machine body is switched to the forward side and the reverse side to run. The vehicle can be shifted and stopped on the forward side and the reverse side.

  That is, when the speed change operation tool 77 is operated to the neutral position [77N], the reverse operation range “77R” and the forward operation range “77F”, the speed change command from the speed change operation tool 77 and the swash plate angle sensor 75 and The shift transmission 20 is set to HST transmission by switching control of the HMT clutch 55 and the HST clutch 60 of the shift control means 78 based on the detection information by the output speed sensor 79 and the setting information by the reference swash plate angle setting means 80. When the speed change operation tool 77 is operated to the high speed side of the forward operation range “77F”, a speed change command from the speed change operation tool 77, information detected by the swash plate angle sensor 75 and the output rotation speed sensor 79, reference swash plate angle setting means By the switching control of the HMT clutch 55 and the HST clutch 60 of the shift control means 78 based on the setting information 80, the transmission 20 is set to HMT transmission.

  When the speed change operation tool 77 is operated to the neutral position “77N”, the speed change control means 78 operates the swash plate 32b of the hydraulic pump 32 to the neutral position “n” based on the speed change command from the speed change operation tool 77. The part 30 becomes a neutral state, and the transmission 20 stops the output.

  When the speed change operation tool 77 is moved in the low speed range portion of the forward operation range “77F”, the speed change control means 78 is controlled by the shift command of the hydraulic pump 32 based on the speed change command from the speed change operation tool 77 and information detected by the output rotation speed sensor 76. The plate 32b is tilted on the forward side from the neutral position “n”, and the driving force output from the transmission 20 shifts along the forward region of the load HST shift line SA.

  When the speed change operation tool 77 is moved and operated in the high speed region of the forward operation range “77F”, the speed change control means 78 is operated in accordance with the speed change command from the speed change operation tool 77 and information detected by the output rotation speed sensor 76. The plate 32b is tilted between the forward side and the reverse side, and the driving force output from the transmission 20 is shifted along the load HMT shift line MA.

  When the shift operation tool 77 is moved in the reverse operation range “77R”, the shift control means 78 neutralizes the swash plate 32b of the hydraulic pump 32 based on the shift command from the shift operation tool 77 and the detection information by the output rotation speed sensor 76. Tilt operation is performed on the reverse side from the position “n”, and the driving force output from the transmission 20 shifts along the reverse range of the HST shift line SA of the load.

  FIG. 13 is an explanatory diagram showing switching from HST transmission to HMT transmission in the comparative example. The horizontal line L1 shown in FIG. 13 is the same as the horizontal line L1 shown in FIG.

  As shown in FIGS. 10 and 13, the rotation speed of the motor shaft 33 a that is accelerated along the HST shift line S becomes the integrated rotation appearing speed “V” between the HST shift line S and the HMT shift line M. The swash plate angle of the hydraulic pump 32 at this point is the unloaded swash plate angle “a” that is the set forward high speed position “a”. The rotation speed of the motor shaft 33a increasing along the HST shift line SA becomes the integral rotation appearing speed “V” at the time point indicated by the intersection “X” between the HST shift line SA and the horizontal line L1, At this time, the swash plate angle of the hydraulic pump 32 becomes the load swash plate angle “b”, and the load swash plate angle “b” tilts the swash plate 32 b to the higher speed side than the unloaded swash plate angle “a”. Swash plate corner.

  When the rotational speed of the motor shaft 33a that increases along the HST shift line SA reaches the integrated rotation output speed “V”, the HST clutch 60 is switched to the disengaged state to switch the setting from HST transmission to HMT transmission. When this is done, the output speed of the output rotator 24 is the intersection where the HMT shift line MA intersects with the vertical line passing through the position of the intersection "X" and the load swash plate angle "b" from the integrated rotation appearance speed "V". The rotation speed corresponds to “Y”, and changes to a rotation speed “V0” that is lower than the integrated rotation appearance speed “V”. That is, when the HST clutch 60 is switched to the disengaged state and the setting is switched from the HST transmission to the HMT transmission, immediately after the switching, the speed corresponding to the integrated rotation appearing speed “V” is changed to the output speed “V0”. The running speed drops to the corresponding speed.

  FIG. 12 is an explanatory diagram showing switching of setting from HST transmission to HMT transmission by the shift control means 78 according to the embodiment of the present invention. The swash plate angle “c” shown in this figure is the set reference swash plate angle “c” set by the reference swash plate angle setting means 80.

  As shown in FIG. 12, the shift control means 78 is driven by the HST transmission and load drive, and the output speed of the continuously variable transmission 30 that increases the speed along the HST shift line SA appears as an integral rotation. The detection information by the swash plate angle sensor 75 is always input until the speed becomes “V”, and the detection information by the swash plate angle sensor 75 and the storage unit 83 (FIG. 9), the calculation HST shift line SA1 in the HST transmission and load drive corresponding to the swash plate angle detected by the swash plate angle sensor 75 is calculated and set. A calculation HMT shift line MA1 corresponding to the HST shift line SA1 is calculated and set.

  When the calculation control unit 78 calculates and sets the calculation HMT shift line MA1, the shift control unit 78 calculates an intersection “G” between the calculation HMT shift line MA1 and the horizontal line L1, and calculates a swash plate angle “e” corresponding to the intersection “G”. The swash plate angle “e” is used to shift the continuously variable transmission 30 to a shift state in which a shift driving force of a speed corresponding to the integrated rotation appearing speed “V” on the calculation HMT shift line MA1 is output. The swash plate angle is set as the target swash plate angle “e”. The return angle required to return the swash plate 32b from the load swash plate angle “b” corresponding to the intersection [X] to the return target swash plate angle “e” is set as the set return angle “E”.

  As shown in FIGS. 11 and 12, the shift control means 78 is such that the output speed of the continuously variable transmission unit 30 in the HST transmission becomes the integrated rotation appearing speed [V], and the swash plate angle of the hydraulic pump 32 is set as a reference. When it is detected that the swash plate angle “c” is higher than the swash plate angle “c”, the swash plate angle is changed from the load swash plate angle “b” to the set return angle “E” while maintaining the HST clutch 60 and the HMT clutch 55 in the engaged state. Only the return operation is performed to return to the return target swash plate angle “e”. When the speed change control means 78 returns the swash plate angle by the set return angle “E”, the HST clutch 55 is then controlled to be switched off, thereby maintaining the HMT clutch 55 in the engaged state. The HST clutch 60 is controlled to be disengaged and the HMT clutch 55 is controlled to be engaged. Even if the HST clutch 60 is disengaged and the setting is switched to HMT transmission, the transmission of the transmission 20 immediately after the switching is performed. Switching control of setting from HST transmission to HMT transmission is performed in a state where the output speed becomes the integral rotor appearance speed “V”. The setting switching control from the HST transmission to the HMT transmission is performed in a state where the speed change operation tool 77 is located in the intermediate portion of the forward operation area 77F.

[Another Example]
(1) In the above-described embodiment, the setting return angle “E” that is set based on the calculation HST shift line SA1 and the calculation HMT shift line MA1 and changes depending on the load is adopted. The return angle “E” may be adopted.

(2) In the above-described embodiment, the swash plate angle corresponding to the intersection “G” between the load HMT shift line MA and the horizontal axis L1 is set as the return target swash plate angle “e”. In the example, the return angle for returning the swash plate 32b to the set return angle “E” is shown. However, the swash plate angle corresponding to the intersection “G” such as the unloaded swash plate angle “a” is shown. Alternatively, a configuration may be adopted in which the set return angle is set by setting the swash plate angle lower than the load swash plate angle “b” as the target swash plate angle on the high speed side.

(3) In the above-described embodiment, an example in which the clutch mechanism 70 is configured by the bite type HMT clutch 55 and the HST clutch 60 is shown, but the clutch mechanism 70 is configured by the friction type HMT clutch 55 and the HST clutch 60. May be implemented.

(4) In the above-described embodiment, an example in which the continuously variable transmission unit 30 is configured by including the fixed displacement type hydraulic motor 33 is shown. However, the continuously variable transmission unit 30 is configured by including a variable displacement type hydraulic motor. May be implemented.

  INDUSTRIAL APPLICABILITY The present invention can be used for various agricultural machines such as a rice transplanter and a transporter in addition to a combine.

DESCRIPTION OF SYMBOLS 1 Traveling device 8 Engine 20 Transmission transmission 24 Output rotary body 30 Continuously variable transmission part 32 Hydraulic pump 32b Swash plate 40 Planetary transmission part 41 Carrier 42 Sun gear 44 Ring gear 55 HMT clutch 60 HST clutch 75 Swash plate angle sensor 77 Shifting operation tool 78 Shift control means 80 Shift swash plate angle setting means a No load swash plate angle b Load swash plate angle c Setting reference swash plate angle e Return target swash plate angle E Set return angle S HST shift line M HMT shift line V Integral rotation appearance Speed SA1 Calculation HST shift line MA1 Calculation HMT shift line

Claims (2)

A hydrostatic continuously variable transmission that operates to input and shift the driving force from the engine and shift the output driving force along the HST shift line, and the driving force from the engine and the continuously variable transmission. A shift transmission having a planetary transmission that acts so as to shift the combined drive force from the variable speed drive along the HMT shift line by the shift of the continuously variable transmission;
By switching between the HST clutch that sets the HST transmission and the HMT clutch that sets the HMT transmission, the HST transmission that outputs the shift driving force output from the continuously variable transmission unit from the output rotating body to the traveling device, and the planetary transmission unit outputs And configured to switch the transmission to HMT transmission that outputs the combined driving force to the traveling device from the output rotating body,
A traveling transmission device for an agricultural working machine comprising a shift control means for performing a shift control of a hydraulic pump that constitutes the continuously variable transmission unit based on a shift command from a shift operation tool and for switching and controlling the HST clutch and the HMT clutch. ,
A swash plate angle sensor for detecting a swash plate angle of the hydraulic pump;
In a speed change state in which the continuously variable transmission portion in HST transmission and no-load drive outputs a speed change driving force corresponding to an integral rotation appearing speed at which the sun gear, carrier and ring gear of the planetary transmission portion appear to rotate integrally. Reference swash plate angle setting means for setting a no-load swash plate angle provided in the hydraulic pump as a set reference swash plate angle,
When the output speed of the continuously variable transmission unit in the HST transmission becomes the integrated rotation actual speed, the swash plate angle of the hydraulic pump is determined based on the detection information by the swash plate angle sensor. By detecting that the swash plate angle is higher than the swash plate angle, the swash plate of the hydraulic pump is returned to the low speed side by a set return angle while maintaining the HST clutch and the HMT clutch in an engaged state. A traveling transmission device for an agricultural machine configured to switch and control the HST clutch and the HMT clutch to switch from HST transmission to HMT transmission later.   The shift control means calculates and sets a calculation HST shift line for HST transmission and load driving based on detection information from the swash plate angle sensor, sets a calculation HMT shift line corresponding to the calculation HST shift line, The swash plate angle for shifting the continuously variable transmission unit is returned to a shift state in which a shift driving force at a speed corresponding to the integrated rotation appearing speed is output on the line of the calculated HMT shift line. The traveling transmission device for an agricultural machine according to claim 1, wherein a return angle required for returning the swash plate to a target swash plate angle is set as the set return angle.

Images