JP2011179563A - Working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform switching operation of a shifting gear mechanism 51 with a small operation force to lower an operation burden of an operator in a working vehicle including a hydraulic continuously variable transmission 53, which transmits power of an engine 14 mounted on a traveling machine body 1 to the shifting gear mechanism 51, and a continuously variable transmission actuator 277 for regulating a speed change output of the hydraulic continuously variable transmission 53. <P>SOLUTION: The working vehicle includes a multistage shifting actuator 475 for switching the shifting gear mechanism 51 to a shifting position selected by a shifting control body 44. A switching arm 472 associated with the shifting gear mechanism 51 is interlockingly connected to the multistage shifting actuator 475 with damper members 473 and 474. This configuration allows the shifting gear mechanism 51 to smoothly switched through drive of the multistage gear change actuator 475. Then, the operator can operate selection of the shifting gear mechanism 51 with a small operating force, reducing a control burden on the operator. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a work vehicle such as a farm work machine such as a combine machine or a special work machine such as a crane truck.

  Conventionally, in a combine as a work vehicle, the power of an engine mounted on a traveling machine body is transmitted to left and right traveling crawlers via a hydraulic continuously variable transmission and a gear-type auxiliary transmission mechanism (switching between low speed and high speed). Is configured to communicate. An example of a combine having such a configuration is disclosed in Patent Document 1. The shift output amount of the hydraulic continuously variable transmission, that is, the straight traveling speed of the traveling machine body is adjusted mainly according to the operation amount of the main transmission lever provided in the control section of the traveling machine body. The gear-type sub-transmission mechanism switches the shift output range of the hydraulic continuously variable transmission to two stages, and is switched by manual operation of the sub-transmission lever provided in the control unit. In this case, the sub-transmission mechanism has a meshing-type dog clutch, and the dog clutch is connected to the sub-transmission low-speed gear or the sub-transmission high-speed gear by the sliding operation of the sub-transmission shifter (dog clutch) by manual operation of the sub-transmission lever. To connect to. As a result, the shift output of the hydraulic continuously variable transmission is switched to a two-stage shift speed of low speed or high speed by each gear.

JP-A-10-95363

  However, in the above-described conventional configuration, the dog clutch engagement / disengagement operation (sub-transmission shifter sliding operation) is performed by manual operation of the sub-transmission lever. For example, the engagement of the dog clutch becomes out of phase and cannot move. If the auxiliary transmission shifter is locked, rotational torque is closed to the auxiliary transmission mechanism. Therefore, a large amount of force is required for manual operation of the auxiliary transmission lever to release the locked state (the operational feeling is “ There is a problem that the operation burden on the operator is heavy.

  Therefore, the present invention has a technical problem to provide a work vehicle that solves the above-described problems.

  In order to achieve the technical problem, the invention of claim 1 is directed to a continuously variable transmission that transmits power of a prime mover mounted on a traveling machine body to a transmission gear mechanism, and to adjust a shift output of the continuously variable transmission. And a multi-stage transmission actuator for switching the transmission gear mechanism to a transmission position selected by a transmission operation body, and associated with the transmission gear mechanism. The switching arm and the multi-stage transmission actuator are interlocked and connected via a damper member.

  According to a second aspect of the present invention, in the work vehicle according to the first aspect of the present invention, the work vehicle includes a first detecting unit that detects an operating state of the multi-stage transmission actuator, and a second detecting unit that detects an operating state of the switching arm. In addition, when the detection information of the both detection means matches, the switching operation of the transmission gear mechanism to the transmission position is completed.

  According to a third aspect of the present invention, in the work vehicle according to the second aspect, when the detection information of the both detection means does not match, a predetermined minute amount of output is temporarily output from the continuously variable transmission to the transmission gear mechanism. It is configured to do.

  According to a fourth aspect of the present invention, in the work vehicle according to any one of the first to third aspects, when the speed change output of the continuously variable transmission is zero, the multistage speed change actuator is operated by a selection operation of the speed change operation body. The transmission gear mechanism is configured to operate and to switch to the transmission position corresponding to the transmission operation body.

  According to a fifth aspect of the present invention, in the work vehicle according to any one of the first to fourth aspects, the expansion / contraction stroke of the damper member changes within a range equal to or less than a shift movement distance of one step in the transmission gear mechanism. It is said that it is comprised.

  According to the first aspect of the present invention, the continuously variable transmission for transmitting the power of the prime mover mounted on the traveling machine body to the transmission gear mechanism and the continuously variable transmission actuator for adjusting the shift output of the continuously variable transmission are provided. A multi-stage transmission actuator for switching the transmission gear mechanism to a transmission position selected by a transmission operation body, and a switching arm associated with the transmission gear mechanism and the multi-stage transmission actuator Are interlocked and connected via a damper member, so that the transmission gear mechanism can be smoothly switched by driving the multi-stage transmission actuator. For this reason, the operator can perform the switching operation of the transmission gear mechanism with a light operating force, and the operation burden on the operator is reduced. Particularly in this case, since the damper member is interposed between the switching arm and the multi-stage transmission actuator, for example, even when the transmission gear mechanism is locked so as not to be switched, the degree of locking is compared. If it is moderately loosened, only the elastic restoring force of the damper member can release the lock and release the rotational torque confined in the transmission gear mechanism, so that the transmission gear mechanism can be switched reliably.

  According to a second aspect of the present invention, in the work vehicle according to the first aspect, the first detecting means for detecting the operating state of the multi-stage transmission actuator and the second detecting means for detecting the operating state of the switching arm are provided. When the detection information of both the detection means matches, the switching operation of the transmission gear mechanism to the shift position is completed. The transmission gear mechanism can be switched appropriately, and thereafter, the power can be smoothly transmitted from the continuously variable transmission to the transmission gear mechanism.

  According to a third aspect of the present invention, in the work vehicle according to the second aspect, when the detection information of the both detection means does not match, a predetermined minute amount of output is output from the continuously variable transmission to the transmission gear mechanism. Since it is configured to perform once, for example, even when the transmission gear mechanism is locked so that it cannot be switched, the predetermined minute amount of output is transmitted to the transmission gear mechanism to release the lock. Thus, the rotational torque confined in the transmission gear mechanism can be released. Therefore, there is an effect that the transmission gear mechanism can be switched more reliably regardless of whether or not the transmission gear mechanism is locked.

  According to a fourth aspect of the present invention, in the work vehicle according to any one of the first to third aspects, when the shift output of the continuously variable transmission is zero, the multi-stage shift actuator is selected by the selection operation of the shift operation body. And the transmission gear mechanism is configured to switch to the transmission position corresponding to the transmission operation body. Therefore, when the transmission output is output from the continuously variable transmission, the transmission gear mechanism There is no possibility of switching operation, and it is possible to prevent the vehicle speed (traveling speed) of the traveling machine body from changing suddenly. In addition, engine troubles due to sudden load fluctuations can be suppressed.

  According to a fifth aspect of the present invention, in the work vehicle according to any one of the first to fourth aspects, the expansion / contraction stroke of the damper member changes within a range equal to or less than a shift movement distance of one step in the transmission gear mechanism. Since the damper member is elastically deformed, its length can be expanded and contracted to absorb unnecessary operating force, and malfunction of the transmission gear mechanism can be prevented.

It is a left view of the combine for 6 thread cutting. It is a top view of a combine. It is a drive system diagram of a combine. It is drive system diagrams, such as a mission case. It is a hydraulic circuit diagram of a combine. It is a left view of an engine and a transmission case. It is a top view of an engine and a mission case. It is transmission system explanatory drawing of an engine and a mission case. It is front explanatory drawing of a traveling body and a mission case. It is a left view of a mission case. It is a right view of a mission case. It is side surface explanatory drawing of a subtransmission mechanism. FIG. 7 is an enlarged front explanatory view showing the interlocking relationship between the auxiliary transmission operation shaft and the auxiliary transmission electric motor. It is a functional block diagram of a shift steering controller. It is a flowchart which shows an example of shift steering control. It is a flowchart which shows an example of the switching control of a subtransmission mechanism.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the following description, the left side in the forward direction of the traveling machine body 1 is simply referred to as the left side, and the right side in the forward direction is also simply referred to as the right side.

(1). Overall Structure of Combine The overall structure of the combine will be described with reference to FIGS. 1 and 2. As shown in FIGS. 1 and 2, the combine includes a traveling machine body 1 supported by a pair of left and right traveling crawlers 2 as traveling portions. At the front part of the traveling machine body 1, a six-row mowing device 3 that takes in while harvesting the grain husk is cut by a single-acting lifting hydraulic cylinder 4 as a lifting actuator. The details are described later). A threshing device 5 having a feed chain 6 and a grain tank 7 for storing the grains taken out from the threshing device 5 are mounted on the traveling machine body 1 side by side. The threshing device 5 is disposed on the left side in the forward direction of the traveling machine body 1, and the grain tank 7 is disposed on the right side in the forward direction of the traveling machine body 1. A swivelable discharge auger 8 is provided at the rear part of the traveling machine body 1, and the grains inside the grain tank 7 are discharged from the throat throwing port 9 of the discharge auger 8 to a truck bed or a container. Yes. An operation cabin 10 is provided on the right side of the cutting device 3 and on the front side of the grain tank 7.

  In the driving cabin 10, a steering handle 11 as a turning operation tool, a driving seat 12, a main transmission lever 43 as a straight operation tool, an auxiliary transmission switch 44, a work clutch lever for turning on and off a threshing clutch and a cutting clutch. 45 are arranged. The driving cabin 10 has a step 357 (see FIGS. 6 to 9) on which an operator gets on, a handle column 46 provided with the steering handle 11, a lever column provided with the levers 43 and 45, the switch 44, and the like. 47 are arranged. An engine 14 as a power source (prime mover) is disposed below the driver seat 12 in the traveling machine body 1.

  As shown in FIG. 1, left and right track frames 21 are arranged on the lower surface side of the traveling machine body 1. The track frame 21 includes a drive sprocket 22 that transmits the power of the engine 14 to the traveling crawler 2, a tension roller 23 that maintains the tension of the traveling crawler 2, and a plurality of track rollers that hold the ground side of the traveling crawler 2 in a grounded state. 24 and an intermediate roller 25 that holds the non-grounded side of the traveling crawler 2 are provided. The driving sprocket 22 supports the front side of the traveling crawler 2, the tension roller 23 supports the rear side of the traveling crawler 2, the track roller 24 supports the grounding side of the traveling crawler 2, and the intermediate roller 25 supports the non-traveling crawler 2. Support the ground side.

  As shown in FIG. 1, a clipper-type cutting blade device 222 that cuts a stock of uncut grain culm planted in a farm is provided below the cutting frame 221 that forms the framework of the cutting device 3. In front of the mowing frame 221, a stalk raising apparatus 223 for six stalks that raises an uncut cereal cultivated in the field is disposed. Between the culm pulling device 223 and the front end (feed start side) of the feed chain 6, a culm conveying device 224 that conveys the chopped culm harvested by the cutting blade device 222 is arranged. In addition, in front of the lower part of the grain raising apparatus 223, a weeding body 225 corresponding to six strips for weeding the uncut grain rice planted in the field is provided. While the traveling crawler 2 is driven by the engine 14 and moved in the field, the uncut cereal grains planted in the field are continuously cut by the cutting device 3.

(2). Next, the structure of the threshing apparatus 5 will be described with reference to FIGS. 1 and 2. As shown in FIGS. 1 and 2, the threshing device 5 includes a handling cylinder 226 for threshing threshing, a rocking sorter 227 that sorts the cereals falling below the handling cylinder 226, and a tang fan 228. A processing cylinder 229 that reprocesses the threshing waste taken out from the rear part of the cylinder 226 and a dust exhaust fan 230 that discharges dust at the rear part of the swing sorter 227 are provided. In addition, the rotating shaft core line of the handling cylinder 226 extends along the conveying direction of the cereal by the feed chain 6 (in other words, the traveling direction of the traveling machine body 1). The stock source side of the corn straw conveyed from the reaping device 3 by the corn straw conveying device 224 is inherited by the feed chain 6 and is nipped and conveyed. Then, the tip side of the cereal cocoon is carried into the handling chamber of the threshing device 5 and threshed by the handling drum 226.

  As shown in FIG. 1, on the lower side of the rocking sorter 227, there are a first conveyor 231 for taking out the grain (first thing) sorted by the rocking sorter 227 and two branches such as a grain with a branch raft. A second conveyor 232 for taking out the articles is provided. The two conveyors 231 and 232 of this embodiment are arranged in the order from the front side in the traveling direction of the traveling machine body 1 to the upper surface side of the traveling machine body 1 above the rear part of the traveling crawler 2 in a side view in order of the first conveyor 231 and the second conveyor 232. It is installed. The aforementioned grain sorting mechanism 245 is constituted by the swing sorter 227, the red pepper fan 228, the first conveyor 231, the second conveyor 232, the dust discharge fan 230, the sorting fan 241, and the like.

  As shown in FIG. 1, the rocking sorter 227 is subjected to rocking sorting (specific gravity sorting) by the feed pan 238 and the chaff sheave 239 from the cereal that has leaked from the receiving net 237 stretched below the handling cylinder 226. It is configured as follows. The grains falling from the rocking sorter 227 are removed by the sorting air from the red pepper fan 228, and fall first on the conveyor 231. A whipping conveyor 233 extending in the vertical direction is connected to a terminal portion of the first conveyor 231 that protrudes outward from one side wall (right side wall in the embodiment) near the grain tank 7 in the threshing device 5. The grain taken out first from the conveyor 231 is carried into the grain tank 7 via the cereal conveyor 233 and collected in the grain tank 7.

  Further, as shown in FIG. 1, the rocking sorter 227 is configured to drop a second thing such as a grain with a branch stem from the chaff sheave 239 onto the second conveyor 232 by rocking sorting (specific gravity sorting). . A sorting fan 241 for wind-selecting the second thing falling below the chaff sheave 239 is provided. As for the second thing that has fallen from the chaff sheave 239, the dust and swarf in the grain are removed by the sorting air from the sorting fan 241 and dropped onto the second conveyor 232. The terminal portion of the second conveyor 232 that protrudes outward from one side wall near the grain tank 7 in the threshing device 5 is located on the upper surface side of the rear part of the feed pan 238 (the front part of the chaff sheave 239) via the reduction conveyor 236. The second connection is returned to the upper surface side of the swing sorter 227 and re-sorted.

  On the other hand, as shown in FIGS. 1 and 2, a waste chain 234 and a waste cutter 235 are arranged on the rear end side (feed end side) of the feed chain 6. The slag passed from the rear end side of the feed chain 6 to the sewage chain 234 (the slag from which the grain has been threshed) is discharged to the rear of the traveling machine body 1 in a long state, or the rear part of the threshing device 5 After being cut to an appropriate length by a waste cutter 235 provided on the rear, the paper is discharged to the lower rear side of the traveling machine body 1.

(3). Next, with reference to FIG. 3, the drive structure of the combine (the drive structure of the reaping device 3, the threshing device 5, the feed chain 6, the waste chain 234, the waste cutter 235, etc.) will be described. As shown in FIG. 3, the output shaft 150 projects from the left side of the engine 14. The traveling input shaft 152 of the transmission case 88 is connected to the output shaft 150 of the engine 14 via the traveling drive belt 151, and the rotational driving force of the engine 14 is transmitted from the front output shaft 150 to the transmission case 88 and shifted. Thereafter, the left and right traveling crawlers 2 are transmitted to the left and right traveling crawlers 2 via the left and right axles 153, and the left and right traveling crawlers 2 are driven by the rotational force of the engine 14.

  As shown in FIG. 3, a cooling fan 154 for a radiator or the like for cooling the engine 14 is provided on the output shaft 150 protruding to the right side of the engine 14. Further, a discharge auger drive shaft 157 is connected to the output shaft 150 on the right side of the engine 14, and the discharge auger 8 is driven via the discharge auger drive shaft 157 by the rotational drive force of the engine 14, so that the grains in the grain tank 7 are transferred. It is configured to be discharged into a container or the like. Further, as shown in FIG. 3, the threshing selection work input shaft 165 that transmits the rotational driving force of the engine 14 to each part of the threshing device 5, and the rotational driving force of the threshing selection work input shaft 165 is transmitted to the handling cylinder 226 and the processing cylinder 230. A threshing drive shaft 160 is provided. A threshing sorting operation input shaft 165 is connected to the output shaft 150 on the left side of the engine 14 via a tension roller type threshing clutch 161 and a threshing drive belt 162. A barrel low speed gear and a barrel high speed gear are arranged on the threshing drive shaft 160. The rotational force of the threshing selection work input shaft 165 is transmitted to the threshing drive shaft 160 via the barrel low speed gear or the barrel high speed gear.

  The threshing drive shaft 160 is connected to a treatment cylinder shaft 163 that supports the treatment cylinder 226 and a processing cylinder shaft 164 that supports the treatment cylinder 230 via a treatment cylinder drive belt 117. The handling cylinder 226 and the processing cylinder 230 are configured to rotate at a predetermined rotation speed (low speed rotation speed or high speed rotation speed) by the rotational force of the engine 14 at a substantially constant rotation speed. In addition, the rotational force of the engine 14 at a substantially constant rotational speed causes the scouring and sorting operation input shaft 165 to pass through the swing sorter 227, the tang fan 228, the first conveyor 231, the second conveyor 232, the sorting fan 241, and the dust exhaust. The fan 230 is configured to rotate at a substantially constant rotational speed.

  As shown in FIGS. 3 to 5, the transmission case 88 includes a linearly traveling (traveling main transmission) hydraulic continuously variable transmission 53 having a pair of linearly traveling first hydraulic pump 55 and a linearly traveling first hydraulic motor 56. A turning hydraulic continuously variable transmission 54 having a pair of turning second hydraulic pumps 57 and a turning second hydraulic motor 58 is provided. The traveling input shaft 152 of the mission case 88 is connected to the first hydraulic pump 55 and the second hydraulic pump 57, respectively, and is driven. A PTO shaft 99 is disposed on the mission case 88. The PTO shaft 99 is driven by the first hydraulic motor 56. One end side of the PTO shaft 99 protrudes from the transmission case 88 to the left outer side.

  A counter gear case 89 (see FIGS. 3, 6, 7 and 9) is provided on the traveling machine body 1 on the left side of the engine 14 and on the front side of the threshing device 5. The counter gear case 89 includes a threshing drive shaft 160, a threshing selection operation input shaft 165 connected to the threshing drive shaft 160, a vehicle speed tuning shaft 100 connected to the PTO shaft 99, and a threshing selection operation input shaft 165 or vehicle speed synchronization. A cutting transmission shaft 101 connected to the shaft 100, a cutting drive shaft 102 connected to the cutting input shaft 17, and a feed chain driving shaft 103 that drives the feed chain 6 and the succeeding auxiliary stock former transfer chain 136 are arranged. . On the vehicle speed tuning shaft 100 in the counter gear case 89, a one-way clutch for transmitting the vehicle speed tuning rotational force of the vehicle speed tuning shaft 100 is provided. A cutting transmission shaft 101 is coupled to the vehicle speed tuning shaft 100 via a cutting transmission mechanism and a one-way clutch. The cutting transmission mechanism has a low speed side transmission gear and a high speed side transmission gear. The low-speed side shifting gear or the high-speed side transmission gear is selectively engaged with the cutting transmission shaft 101 by the cutting shift operating means for performing the low-speed, neutral (zero rotation) and high-speed cutting shifts. The cutting gear shift output is transmitted to the cutting transmission shaft 101 via the mechanism.

  The mowing transmission shaft 101 is connected to the threshing selection work input shaft 165 via a constant rotation mechanism. The constant rotation mechanism has a low speed side constant rotation gear and a high speed side constant rotation gear. The cutting drive shaft 102 is connected to the cutting transmission shaft 101 via a torque limiter. The cutting input shaft 17 is connected to the cutting drive shaft 102 via the cutting drive pulley 124 and the cutting drive belt 125, and the cutting drive force is transmitted from the cutting drive shaft 102 to the cutting device 3. A rotation output at a constant rotational speed necessary for maintaining the cutting operation is transmitted from the threshing selection operation input shaft 165 to the cutting transmission shaft 101 via the low-speed constant rotation gear. Therefore, regardless of the moving speed of the traveling machine body 1, the cutting input shaft 17 can be operated at a constant rotation speed from the low-speed constant rotation gear to maintain the cutting operation, and the direction change workability at the headland in the field is improved. it can.

  Further, a rotational output of a constant rotational speed faster than the maximum speed of the vehicle speed synchronous output from the vehicle speed tuning shaft 100 and the high speed side transmission gear is transferred from the threshing selection work input shaft 165 to the cutting transmission shaft 101 via the high speed side constant rotational gear. Communicated. Accordingly, the cutting input shaft 17 can be driven at a constant rotational speed from the high-speed constant rotational gear that is faster than the maximum speed of the vehicle speed synchronized output, so that the workability of harvesting the fallen cereal can be improved. Note that the cutting blade 132 and the like are prevented from being damaged by driving the cutting input shaft 17 with a rotational force equal to or less than the torque set by the torque limiter.

  The counter gear case 89 is provided with a planetary gear-type shift structure feed chain tuning mechanism that connects the feed chain drive shaft 103 to the threshing sorting operation input shaft 165. The rotational output of the threshing selection work input shaft 165 is shifted in proportion to the rotational speed of the cutting transmission shaft 101 by the feed chain tuning mechanism and transmitted to the feed chain drive shaft 103. That is, by operating the feed chain 6 and the inheritance auxiliary stock former transport chain 136 via the feed chain tuning mechanism, the minimum rotational speed (constant rotational speed from the low-speed constant rotational gear) required for transporting the cereals is reduced. While ensuring, the grain straw conveyance speed of the feed chain 6 and the inheritance auxiliary stock former conveyance chain 136 can be changed in synchronization with the vehicle speed.

  As shown in FIG. 3, the pulling lateral transmission shaft 143 is connected to the cutting input shaft 17 via the longitudinal transmission shaft 140, the lateral transmission shaft 141, and the left conveyance drive shaft 142. The pulling lateral transmission shaft 143 is connected to the pulling tine drive shaft 144 of each pulling case 29 for six lines. A pulling case 129 is erected on the rear side of the weeding body 225 and above the weeding frame 20, and the pulling tine drive shaft 144 protrudes from the upper rear side of the pulling case 129. The pulling tine chain 128a provided with a plurality of pulling tines 128 is driven via the pulling tine drive shaft 144 and the pulling lateral transmission shaft 143. As shown in FIG. 3, the left and right cutting blades 132 are connected to the lateral transmission shaft 141 via the left and right crankshafts 145. The left and right cutting blades 132 are driven in conjunction with each other via the lateral transmission shaft 141. The cutting blade device 222 is divided at the central portion of the cutting width for six lines to form the left and right cutting blades 132, and the left and right cutting blades 132 are reciprocated in opposite directions, and the left and right generated by the reciprocating movement. The cutting blade 132 is configured to be able to cancel the vibration (inertial force).

  As shown in FIG. 3, one end side of the longitudinal transmission shaft 140 in the longitudinal transmission case 18 is connected to the cutting input shaft 17. The lateral transmission shaft 141 in the lateral transmission case 19 is connected to the other end side of the longitudinal transmission shaft 140. The rotational force of the cutting input shaft 17 is transmitted from the vertical transmission shaft 140 and the horizontal transmission shaft 141 to each drive unit of the cereal conveying device 224. In other words, the right transmission drive shaft 146 is connected to the vertical transmission shaft 140. The right stock former transport chain 133R, the right star wheel 130R, the right take-up belt 131R, and the vertical transport chain 134 are driven via the vertical transmission shaft 140 and the right transport drive shaft 146. In addition, a rear conveyance drive shaft 147 is coupled to the longitudinal transmission shaft 140 behind the right conveyance drive shaft 146. The auxiliary stock former conveyance chain 135 and the right tip conveyance tine 137 </ b> R are driven via the vertical transmission shaft 140 and the rear conveyance drive shaft 147.

  Further, the left transport drive shaft 142 is connected to the left end side of the horizontal transmission shaft 141. The left stock former transport chain 133L and the left tip transport tine 137L, the left star wheel 130L, and the left take-up belt 131L are driven via the left transport drive shaft 142. Further, a central transport drive shaft 148 is connected to the lateral transmission shaft 141, and the central stock transport chain 133C and the central tip transport tine 137C, the central star wheel 130C, and the central scraping belt 131C are connected via the central transport drive shaft 148. Is configured to be driven.

(4). Next, the power transmission structure of the mission case 88 will be described with reference to FIGS. As shown in FIGS. 3 and 4, the transmission case 88 includes a linearly-traveling (traveling main transmission) hydraulic continuously variable transmission 53 having a pair of linearly-moving first hydraulic pump 55 and a linearly-moving first hydraulic motor 56. And a turning hydraulic continuously variable transmission 54 having a turning second hydraulic pump 57 and a turning second hydraulic motor 58. The traveling input shaft 152 of the transmission case 88 is connected to the first hydraulic pump 55 and the second hydraulic pump 57, respectively, and is driven. A travel input pulley 155 is provided on the travel input shaft 152, and the travel drive belt 151 is wound around the travel input pulley 155. A PTO shaft 99 is arranged in the mission case 88. The PTO shaft 99 is driven by a first hydraulic motor 56 via a straight traveling motor shaft 60 and a main transmission output counter shaft 70. One end side of the PTO shaft 99 protrudes from the transmission case 88 to the left outer side. A PTO pulley 119 is provided on the PTO shaft 99, and a PTO belt 120 is wound around the PTO pulley 119.

  As shown in FIG. 4, the driving force output from the output shaft 150 of the engine 14 is pumped by the pump shaft 59 of the first hydraulic pump 55 and the pump of the second hydraulic pump 57 via the travel drive belt 151 and the travel input shaft 152. Each is transmitted to the shaft 59. In the straight-traveling hydraulic continuously variable transmission 53, hydraulic oil is appropriately sent from the first hydraulic pump 55 toward the first hydraulic motor 56 with the power transmitted to the pump shaft 59. Similarly, in the turning hydraulic continuously variable transmission 54, hydraulic oil is appropriately sent from the second hydraulic pump 57 toward the second hydraulic motor 58 with the power transmitted to the pump shaft 59. A charge pump 251 for supplying hydraulic oil to the hydraulic pumps 55 and 57 and the hydraulic motors 56 and 58 is attached to the pump shaft 59.

  The straight-traveling hydraulic continuously variable transmission 53 changes and adjusts the inclination angle of the swash plate 55a in the first hydraulic pump 55 according to the operation amount of the main transmission lever 43 and the steering handle 11 arranged in the driving cabin 10, By changing the discharge direction and discharge amount of the hydraulic oil to the first hydraulic motor 56, the rotation direction and the rotation speed of the linear motor shaft 60 protruding from the first hydraulic motor 56 are arbitrarily adjusted. Yes. As shown in FIG. 4, the rotational power of the linear motor shaft 60 is transmitted from the linear transmission gear 50 to the auxiliary transmission mechanism 51. The sub transmission mechanism 51 includes a sub transmission low speed gear 62 and a sub transmission high speed gear 63 that are switched by a sub transmission shifter 64. By operating an auxiliary transmission switch 44 as a speed change operation body arranged in the lever column 47, the output rotational speed of the linear motor shaft 60 is switched to two speeds of low speed or high speed. Note that a neutral position (a position where the output of the sub-shift is zero) is between the low speed and the high speed of the sub-shift. The auxiliary transmission switch 44 includes a low speed switching button 44a, a neutral switching button 44b, and a high speed switching button 44c. By pressing the low-speed switching button 44a, the neutral switching button 44b, or the high-speed switching button 44c, the sub-shift output is selectively switched to the low speed output, neutral or high speed output.

  As shown in FIG. 4, a parking brake shaft 65 (subtransmission output shaft) provided on the output side of the subtransmission mechanism 51 is provided with a wet multi-disc disc brake 66. The rotational power from the subtransmission mechanism 51 is transmitted to the left and right differential mechanisms 52 from a subtransmission output gear 67 fixed to the parking brake shaft 65. The left and right differential mechanisms 52 are each provided with a planetary gear mechanism 68. Further, a straight traveling pulse generating rotary wheel 92 is provided on the parking brake shaft 65, and a straight traveling pickup rotation sensor 93 (straight vehicle speed sensor) is disposed opposite to the straight traveling pulse generating rotating wheel 92 so that the straight traveling pickup rotation is performed. The sensor 93 is configured to detect the rotation speed of the straight-ahead output (straight-ahead vehicle speed, auxiliary transmission output gear 67 output).

  As shown in FIG. 4, each of the left and right planetary gear mechanisms 68 includes one sun gear 71, a plurality of planetary gears 72 meshing with the sun gear 71, a ring gear 73 meshing with the planetary gear 72, and a plurality of planetary gears 72 in the same circle. And a carrier 74 rotatably disposed on the circumference. The carriers 74 of the left and right planetary gear mechanisms 68 are arranged on the same axis so as to oppose each other with an appropriate interval. A center gear 76 is fixed to a sun gear shaft 75 provided with left and right sun gears 71. The left and right ring gears 73 are arranged concentrically with the sun gear shaft 75 in a state where the inner teeth of the inner peripheral surface thereof are engaged with the plurality of planetary gears 72. Each of the left and right ring gears 73 is connected to the relay shaft 85 with the outer teeth of the outer peripheral surface meshing with the left and right turning output gear 86. Each ring gear 73 is rotatably supported by left and right forced differential output shafts 77 projecting left and right outward from the outer surface of the carrier 74. Left and right axles 153 are connected to the left and right forced differential output shafts 77 via final gears 78a and 78b. Left and right drive sprockets 22 are attached to the left and right axles 153. Accordingly, the rotational power transmitted from the auxiliary transmission mechanism 51 to the left and right planetary gear mechanisms 68 is transmitted from the left and right axles 153 to the drive sprockets 22 at the same rotational speed in the same direction, and the left and right traveling crawlers 2 are transmitted in the same direction. And the traveling machine body 1 is moved straight (forward, backward).

  The turning hydraulic continuously variable transmission 54 changes and adjusts the inclination angle of the swash plate 57a in the second hydraulic pump 57 in accordance with the operation amount of the main transmission lever 43 and the steering handle 11 arranged in the driving cabin 10, By changing the discharge direction and discharge amount of the hydraulic oil to the second hydraulic motor 58, the rotation direction and the rotation speed of the turning motor shaft 61 protruding from the second hydraulic motor 58 are arbitrarily adjusted. Yes. Further, a turning pulse generating rotary wheel 94 is provided on a steering counter shaft 80 which will be described later, and a turning pickup rotation sensor 95 is arranged to face the turning pulse generating rotary wheel 94 so that the turning pickup rotation sensor 95 is turned. The rotation speed (turning vehicle speed) of the steering output of the second hydraulic motor 58 is detected by the (turning vehicle speed sensor).

  Further, in the mission case 88, a steering brake 79 (swing brake) provided on the turning motor shaft 61 (steering input shaft) and a steering counter connected to the turning motor shaft 61 via a reduction gear 81 are provided. A steering output shaft 85 connected to the steering counter shaft 80 via a reduction gear 86; a left input gear mechanism 82 connecting the steering output shaft 85 to the left ring gear 73 via a reverse gear 84; A right input gear mechanism 83 that connects the steering output shaft 85 to the right ring gear 73 is provided. The rotational power of the turning motor shaft 61 is transmitted to the steering counter shaft 80. The rotational power transmitted to the steering counter shaft 80 is transmitted to the left ring gear 73 as reverse rotational power via the left intermediate gear 87 and the reverse gear 84 of the left input gear mechanism 82, and the right input gear mechanism 83. It is transmitted to the right ring gear 73 as forward rotation power through the right intermediate gear 87.

  When the subtransmission mechanism 51 is neutral, power transmission from the first hydraulic motor 56 to the left and right planetary gear mechanisms 68 is blocked. When a sub-shift output other than neutral is output from the sub-transmission mechanism 51, power is transmitted from the first hydraulic motor 56 to the left and right planetary gear mechanisms 68 via the sub-transmission low speed gear 62 or the sub transmission high speed gear 63. On the other hand, when the output of the second hydraulic pump 57 is in the neutral state and the steering brake 79 is in the on state, power transmission from the second hydraulic motor 58 to the left and right planetary gear mechanisms 68 is blocked. When the output of the second hydraulic pump 57 is set to a state other than neutral and the steering brake 79 is turned off, the rotational power of the second hydraulic motor 58 is left via the left input gear mechanism 82 and the reverse gear 84. While being transmitted to the ring gear 73, it is transmitted to the right ring gear 73 via the right input gear mechanism 83.

  As a result, at the time of forward rotation (reverse rotation) of the second hydraulic motor 58, the left ring gear 73 rotates reversely (forward rotation) and the right ring gear 73 rotates forward (reverse rotation) at the same rotation speed in the opposite directions. That is, the shift output from the motor shafts 60 and 61 is transmitted to the drive sprockets 22 of the left and right traveling crawlers 2 via the auxiliary transmission mechanism 51 or the differential mechanism 52, respectively, and the vehicle speed of the traveling machine body 1 (traveling). Speed) and direction of travel are determined. That is, when the first hydraulic motor 56 is driven while the second hydraulic motor 58 is stopped and the left and right ring gears 73 are stationary, the rotational output from the linear motor shaft 60 is output to the left and right sun gears 71 at the same left and right rotational speed. The left and right traveling crawlers 2 are driven at the same rotational speed in the same direction via the planetary gear 72 and the carrier 74, and the traveling machine body 1 travels straight.

  Conversely, when the second hydraulic motor 58 is driven in a state where the first hydraulic motor 56 is stopped and the left and right sun gears 71 are stationary, the left ring gear 73 is rotated by the rotational power from the turning motor shaft 61. The ring gear 73 rotates forward (reverse) and the right ring gear 73 rotates reverse (forward). As a result, one of the driving sprockets 22 of the left and right traveling crawlers 2 rotates forward, the other rotates backward, and the traveling machine body 1 changes its direction on the spot (reliable turning spin turn). Further, when the left and right sun gears 71 are driven by the first hydraulic motor 56 and the left and right ring gears 73 are driven by the second hydraulic motor 58, a difference occurs in the speed of the left and right traveling crawlers 2, and the traveling machine body 1 moves forward or backward. While turning to the left or right (U-turn) with a turning radius larger than the belief turning radius. The turning radius at this time is determined according to the speed difference between the left and right traveling crawlers 2.

(5). Combined Hydraulic Circuit Structure Next, the combined hydraulic circuit structure will be described with reference to FIG. As shown in FIG. 5, the combined hydraulic circuit 250 includes a first hydraulic pump 55 and a first hydraulic motor 56 for straight travel, a second hydraulic pump 57 and a second hydraulic motor 58 for turning, a charge pump 251, and the like. Is provided. The first hydraulic pump 55 and the first hydraulic motor 56 are connected by a closed loop straight oil passage 252. The second hydraulic pump 57 and the second hydraulic motor 58 are connected by a closed loop revolving oil passage 253. The first hydraulic pump 55 and the second hydraulic pump 57 are driven by the engine 14, and the first hydraulic motor 56 or the second hydraulic pressure is controlled by the swash plate angle control of the first hydraulic pump 55 or the swash plate angle control of the second hydraulic pump 57. The motor 58 is configured to perform forward rotation or reverse rotation.

  On the other hand, an electro-hydraulic steering valve 270 that is electrically switched in response to manual operation of the steering handle 11 and a steering cylinder 271 that is connected to the charge pump 251 via the electro-hydraulic steering valve 270 are provided. When the electrohydraulic steering valve 270 is switched corresponding to the steering angle of the steering handle 11 detected by the steering angle sensor 402, the steering cylinder 271 is activated to change the swash plate 57a angle of the second hydraulic pump 57. The rotation speed of the second hydraulic motor 58 is changed steplessly, or the left and right steering operation is performed to reverse the direction, the direction of travel is changed to the left and right, and the direction is changed on the field headland. Correct the course. In addition, a steering hydraulic servo mechanism 275 is provided, and the hydraulic servo mechanism 275 performs a feedback operation in which the electromagnetic hydraulic steering valve 270 is neutrally returned by the angle adjustment operation of the swash plate 57a. The angle of the swash plate 57a is changed in proportion to the operation amount, and the rotational speed of the turning motor shaft 61 of the second hydraulic motor 58 is changed.

  Further, as shown in FIG. 5, an electrohydraulic shift valve 272 that is electrically switched in response to manual operation of the main shift lever 43, and a shift cylinder that is connected to the charge pump 251 via an electrohydraulic shift valve 272. 273 is provided. When the electrohydraulic shift valve 272 is switched in accordance with the operation amount of the main shift lever 43 detected by the main shift sensor 401, the shift cylinder 273 is operated to change the angle of the swash plate 55a of the first hydraulic pump 55. A traveling speed change operation is performed in which the rotational speed of the straight traveling motor shaft 60 of the first hydraulic motor 56 is steplessly changed or reversed. In addition, a hydraulic servo mechanism 277 for traveling speed change as a continuously variable transmission actuator is provided, and the hydraulic servo mechanism 277 is caused to perform a feedback operation in which the electromagnetic hydraulic shift valve 272 is neutrally returned by the angle adjustment operation of the swash plate 55a. The angle of the swash plate 55a is changed in proportion to the amount of operation of the main transmission lever 43, the rotational speed of the linear motor shaft 60 of the first hydraulic motor 56 is changed, and the linear motor shaft 60 is moved by the operation of the main transmission lever 43. It is configured to rotate forward and backward.

  Further, as shown in FIG. 5, a hydraulic cutting gear shift cylinder 280 for switching the operating speed of the cutting device 3 and a hydraulic cutting constant speed cylinder 281 for operating the cutting device 3 at a constant rotational speed are provided. The hydraulic cutting gear shift cylinder 280 and the hydraulic cutting constant speed cylinder 281 are arranged on the top cover (oil path base) of the counter gear case 89. A cutting speed change valve 282 for operating the cutting speed change cylinder 280 and a cutting speed control valve 283 for operating the constant cutting speed cylinder 281 are hydraulically connected to the charge pump 251 in parallel.

(6). Next, the power transmission structure of the engine 14, the transmission case 88, and the counter gear case 89 will be described with reference to FIGS. 1 to 3 and FIGS. As shown in FIGS. 1, 2, and 6 to 8, the engine 14 is mounted on the right side of the upper surface of the traveling machine body 1, and a transmission case 88 is installed in front of the center of the left and right width of the traveling machine body 1. A counter gear case 89 is arranged on the upper left side. An output pulley 149 is pivotally supported on the left end portion of the output shaft 150 extended in the left-right direction in the engine 14, and a traveling drive belt 151 is hung between the traveling input pulley 155 and the output pulley 149 on the upper left side of the mission case 88. It is turning. With this configuration, the output of the engine 14 is transmitted to each of the hydraulic continuously variable transmissions 53 and 54 of the mission case 88.

  On the other hand, a columnar frame 290 that supports the discharge auger 8 in a storage (non-working) position is erected on the upper surface of the traveling machine body 1, and a PTO countershaft 121 is mounted on the front surface of the base end portion of the columnar frame 290 via a bearing body 291. Is rotatably supported. The PTO belt 120 is wound around the PTO counter pulley 122a on the PTO counter shaft 121 and the PTO pulley 119 below the traveling input pulley 155 in the upper left portion of the mission case 88. A vehicle speed tuning belt 123 is wound around the PTO counter pulley 122 b on the PTO counter shaft 121 and the vehicle speed tuning pulley 104 fixed to the vehicle speed tuning shaft 100 of the counter gear case 89. With this configuration, the vehicle speed tuning driving force of the transmission case 88 is transmitted from the PTO shaft 99 to the vehicle speed tuning shaft 100.

  Further, a threshing drive belt 162 is wound around an output pulley 149 on the output shaft 150 of the engine 14 and a threshing drive pulley 118 fixed to the threshing selection work input shaft 165 of the counter gear case 89. Moreover, the threshing clutch electric motor 175 as a threshing input actuator which switches the threshing clutch 161 is provided. By operating the threshing clutch electric motor 175 and turning on and operating the threshing clutch 161, the threshing drive belt 162 is maintained in a tension state, and the output of the engine 14 is transmitted to the counter gear case 89, while the threshing clutch 161 is turned off. By operation, the threshing drive belt 162 is maintained in a relaxed state, and output transmission from the engine 14 to the counter gear case 89 is interrupted.

  A clutch unit chassis 176 is arranged behind the engine 14 on the traveling machine body 1, and a threshing clutch insertion / closing mechanism 177 is assembled to the clutch unit chassis 176, and an electric motor 175 for threshing clutch is provided on the clutch unit chassis 176. A threshing clutch electric motor 175 is connected to a tension arm (not shown) that supports the threshing clutch 161 via a threshing clutch on / off mechanism 177. A threshing clutch electric motor 175 is arranged on the opposite side of the counter gear case 89 with a threshing drive pulley 118 on the threshing selection work input shaft 165 supported by the counter gear case 89 interposed therebetween. In this case, it is not necessary to secure a space where the threshing clutch electric motor 175 or the threshing clutch insertion / cutting mechanism 177 is installed on the counter gear case 89 side, so that the threshing driving pulley 118 can be supported close to the right side of the counter gear case 89. Without being restricted by the threshing clutch electric motor 175 or the threshing clutch insertion / cutting mechanism 177, the rigidity of the bearing structure accompanying the extension of the threshing selection work input shaft 165 is not required, and a large gear ratio (reduction ratio) is obtained. A settable large-diameter threshing drive pulley 118 can be easily installed.

(7). Schematic Structure of Mission Case Next, the schematic structure of the mission case 88 will be described with reference mainly to FIGS. The mission case 88 installed in front of the center of the left and right width in the traveling machine body 1 has a split structure that is vertically long and can be divided into left and right. The split case 88 has a substantially hollow box shape by fastening with a plurality of bolts. A hydraulic transmission case 350 containing the straight and turning hydraulic continuously variable transmissions 53 and 54 is attached to the upper side of the left and right side surfaces of the transmission case 88 (upper right side in the embodiment). In this case, the straight hydraulic continuously variable transmission 53 (the first hydraulic pump 55 and the first hydraulic motor 56) is located on the front side in the hydraulic transmission case 350, and the turning hydraulic continuously variable in the rear side in the hydraulic transmission case 350. The transmission 54 (second hydraulic pump 57 and second hydraulic motor 58) is located. A gear train such as the auxiliary transmission mechanism 51 and the differential mechanism 52 as described with reference to FIG.

  The lower portion of the mission case 88 protrudes outward in the left-right direction and protrudes downward in a bifurcated shape, and is roughly formed in a gate shape when viewed from the front. An axle case 351 that protrudes left and right outwards is bolted to a gear case 349 that protrudes downward from the lower portions of the left and right sides of the transmission case 88. An axle 153 is rotatably supported in the left and right axle cases 351, and a drive sprocket 22 is attached to the protruding end of each axle 153. As shown in FIG. 9, the bottom portions of both gear cases 349 are located below the bottom portions of the transmission case 88, and the bottom portions of the transmission case 88 are higher than the left and right axle cases 351 protruding from the respective gear cases 349.

  Now, as shown in FIGS. 6 to 9, power is transmitted to the first hydraulic pump 55 and the second hydraulic pump 57 from the side surface of the transmission case 88 opposite to the hydraulic transmission case 350 (upper left side in the embodiment). A traveling input shaft 152 that is connected so as to be able to transmit is projected outward in the lateral direction. A travel drive belt 151 wound around an output pulley 149 of the engine 14 is wound around a travel input pulley 155 fixed to the projecting end of the travel input shaft 152. A PTO pulley 119 is provided on the projecting end side of the PTO shaft 99 projecting laterally outward from the upper left side surface of the mission case 88. The PTO pulley 119 is located below the travel input pulley 155, and the PTO belt 120 is wound around the PTO pulley 119 and the PTO counter pulley 112a located behind the PTO pulley 119. Between the PTO pulley 119 and the PTO counter pulley 122a, a tension pulley 352 for contacting the PTO belt 120 from below and holding the PTO belt 120 in a tensioned state is provided. The tension pulley 352 is supported by the bearing body 291 of the columnar frame 290 so as to be vertically rotatable, and is configured to always tension the PTO belt 120 by spring bias.

  Below the PTO shaft 99 in the left side surface portion of the mission case 88, a rectilinear pickup rotation sensor 93 (straight vehicle speed sensor) as a rectilinear output detecting means associated with the rectilinear pulse generating rotating wheel 92 in the mission case 88. Similarly, a turning pickup rotation sensor 95 (turning vehicle speed sensor) as a turning output detecting means associated with the turning pulse generating rotating wheel body 94 is provided with a part thereof exposed outward. As shown in FIG. 10, both pickup rotation sensors 93 and 95 are arranged side by side. In this case, both pickup rotation sensors 93 and 95 are located between the PTO shaft 99 and the lower left projecting portion of the transmission case 88, with the straight pickup pickup rotation sensor 93 on the front side and the pickup pickup rotation sensor 95 on the rear side. is doing. A substantially lid-like guard plate 353 with the right side surface and the lower surface side opened is attached to the positions of both pickup rotation sensors 93 and 95 in the left side surface portion of the mission case 88 by bolt fastening. Therefore, the outer peripheral sides of both pickup rotation sensors 93 and 95 are covered with the guard plate 353. If comprised in this way, both the pick-up rotation sensors 93 and 95 can be easily protected from the mud etc. which the traveling crawler 2 rolled up by the single guard board 353. Moreover, it can also contribute to the suppression of the number of parts and the reduction of assembly work man-hours. Furthermore, the harnesses (not shown) of the pickup rotation sensors 93 and 95 can be protected in a wide range.

  As shown in FIG. 10, the upper surface portion of the guard plate 353 according to the embodiment has a shape inclined in a front-rear and rear-high state. For this reason, the mud or the like placed on the guard plate 353 easily slides down the inclined upper surface portion, and accumulation of the mud or the like on the guard plate 353 can be effectively prevented. The right side surface side of the guard plate 353 is blocked by the left side surface portion of the mission case 88, and the lower surface side of the guard plate 353 is blocked by the upper surface side of the lower left projecting portion of the mission case 88. The left and right width dimensions of the guard plate 353 are set to such a size that the guard plate 353 fits between the left side surface portion of the mission case 88 and the PTO pulley 119 when viewed from the front. Further, as shown in FIGS. 8 and 10, the portion of the guard plate 353 that overlaps the tension pulley 352 in the side view is directed toward the left and right side surfaces (left side surface portion in the embodiment) of the mission case 88 on the PTO shaft 99 side. It has a shape inclined inward (a shape bent inward). With this configuration, the power transmission system (PTO) from the mission case 88 can be made compact in the left-right width direction while avoiding interference between the guard plate 353 and the tension pulley 352. It is also effective in avoiding interference with the lifting hydraulic cylinder 4 which is located in the vicinity of the tension pulley.

  As described above, the straight traveling hydraulic continuously variable transmission 53 (the first hydraulic pump 55 and the first hydraulic motor 56) is provided on the front side in the hydraulic transmission case 350 that is bolted to the upper right side of the transmission case 88. Yes. On the rear side in the hydraulic transmission case 350, a turning hydraulic continuously variable transmission 54 (second hydraulic pump 57 and second hydraulic motor 58) is provided. On the front side of the hydraulic transmission case 350, an electromagnetic hydraulic transmission valve 272 as an electric actuator for operating the transmission cylinder 273 for the swash plate 55 a of the first hydraulic pump 55 is provided in the hydraulic circuit 250 ( The unit is assembled so as to communicate with each other (see FIG. 5). Further, on the front side of the hydraulic transmission case 350, the swash plate 55a of the first hydraulic pump 55 is manually operated to manually change the discharge direction and the discharge amount of the hydraulic oil to the first hydraulic motor 56 for the straight advance emergency. A straight operation shaft 355 as a manual operation tool is projected forward. If the rectilinear operation shaft 355 is rotated around its axis, the inclination angle of the swash plate 55a of the first hydraulic pump 55 is changed independently from the electrical control of the electrohydraulic shift valve 272, and the first The discharge direction and discharge amount of the hydraulic oil to the hydraulic motor 56 are changed.

  On the rear side of the hydraulic transmission case 350, an electromagnetic hydraulic steering valve 270 for operating the steering cylinder 271 for the swash plate 57a of the second hydraulic pump 57 is a hydraulic circuit 250 in the hydraulic transmission case 350 (see FIG. 5). It is assembled and unitized so as to communicate with. Further, on the rear side of the hydraulic transmission case 350, an emergency for turning which manually changes the discharge direction and discharge amount of the hydraulic oil to the second hydraulic motor 58 by manually operating the swash plate 57a of the second hydraulic pump 57. A turning operation shaft 356 as a manual operation tool protrudes rearward. If the turning operation shaft 356 is turned around its axis, the inclination angle of the swash plate 57a of the second hydraulic pump 57 is changed independently from the electrical control of the electromagnetic hydraulic steering valve 270, and the second The discharge direction and discharge amount of the hydraulic oil to the hydraulic motor 58 are changed.

  As shown in FIGS. 6 to 9, the step 357 of the traveling machine body 1 is located on one side of the mission case 88 (on the left side in the embodiment). The hydraulic transmission case 350 is located between the step 357 and the mission case 88. In step 357, the internal space 359 surrounded by the frame is opened to the left and right. The straight operation shaft 355 on the front surface side of the hydraulic transmission case 350 as viewed from the left side of step 357 faces the internal space 359 of step 357. By inserting a hand into the internal space 359 from the left side of the step 357, it is possible to manually operate the rectilinear operation shaft 355 on the front side of the hydraulic transmission case 350 from the outside of the traveling machine body 1 (see FIG. 9).

  When adjusting the shift output amount of the linear hydraulic continuously variable transmission 53 by the switching operation of the electrohydraulic shift valve 272 based on a command from the shift steering controller 400 described later, the rectilinear operation shaft 355 is moved by the electrohydraulic shift. It is configured to operate in conjunction with the switching operation of the valve 272. In the embodiment, the shift cylinder 273 is actuated to change the angle of the swash plate 55 a of the first hydraulic pump 55 by the switching operation of the electrohydraulic shift valve 272 based on the command of the shift steering controller 400. Then, along with the change of the swash plate 55a angle, the rectilinear operation shaft 355 automatically rotates about its axis (in conjunction with the swash plate 55a). That is, the operations of the electromagnetic hydraulic shift valve 272 and the straight operation shaft 355 are linked via the swash plate 55 a of the first hydraulic pump 55.

  Further, when adjusting the shift output amount of the turning hydraulic continuously variable transmission 54 by the switching operation of the electrohydraulic steering valve 270 based on the command of the shift steering controller 400, the turning operation shaft 356 is driven by the electrohydraulic type. It is configured to operate in conjunction with the switching operation of the steering valve 270. In the embodiment, the steering cylinder 271 is operated by the switching operation of the electrohydraulic steering valve 270 based on the command of the shift steering controller 400, and the swash plate 57a angle of the second hydraulic pump 57 is changed. Then, as the angle of the swash plate 57a is changed, the turning operation shaft 355 automatically rotates around the axis (in conjunction with the swash plate 57a). That is, the operations of the electrohydraulic steering valve 270 and the turning operation shaft 356 are linked via the swash plate 57 a of the second hydraulic pump 57.

  The operation shafts 355 and 356 are not normally operated. For example, the operation shafts 355 and 356 are for emergency avoidance that is operated when a malfunction occurs in the electric system involved in the shift steering control, for example, an abnormality occurs in the shift steering controller 400. is there. Even when such an electric system trouble occurs, if the operation shafts 355 and 356 are manually rotated, the main shift lever 43 and the steering handle 11 are not effective, for example, the combine is escaped only from the field. Such limp home operation (degenerate operation) can be executed. Therefore, there is an effect that the options for dealing with an emergency situation in the combine increase, and that it contributes to the improvement of the handleability of the combine. In limp home operation, it is understood that it is only necessary to go forward and backward through the combine. For this reason, the straight operation shaft 355 on the front side of the hydraulic transmission case 350 as viewed from the left side of step 357 faces the internal space 359 of step 357 so that at least the straight operation shaft 355 can be manually operated from the outside of the traveling machine body 1. It is.

  As shown in FIGS. 10 and 11, a rectilinear lever indicator 361 that facilitates manual rotation of the rectilinear operation shaft 355 is detachably mounted on the projecting end side of the rectilinear operation shaft 355. Similarly, a turning lever indicator 362 that facilitates manual turning operation of the turning operation shaft 356 is detachably attached to the protruding end side of the turning operation shaft 356. The rectilinear lever indicator 361 can constitute an emergency manual operation tool for rectilinear movement together with the rectilinear operation shaft 355, and the turning lever indicator 362 can constitute an emergency manual operation tool for turning together with the turning operation shaft 356. When such a configuration is adopted, the shift output amount of the linear hydraulic continuously variable transmission 53 or the turning hydraulic continuously variable transmission 54 is adjusted by the switching operation of the electromagnetic hydraulic shift valve 272 and the electromagnetic hydraulic steering valve 270. At this time, if the above-described lever indicators 361 and 362 are attached, the operation of the lever indicators 361 and 362 causes the swash plates 55a and 57a of the hydraulic pumps 55 and 57 to be inclined, and consequently the hydraulic continuously variable transmissions 53. , 54 can be easily visually confirmed. In the case where a mechanical connection structure is not provided between the main transmission lever 43 and the steering handle 11 and the both hydraulic continuously variable transmissions 53 and 54, and the space between them is electrically controlled, the main transmission lever 43 and the control handle 11 are controlled. It becomes easy to find an operation trouble related to the handle 11 and the hydraulic continuously variable transmissions 53 and 54 at an early stage.

  In the embodiment, when each of the operation shafts 355 and 356 is manually rotated, the electric control (shift steering control) is prohibited, so that the electromagnetic hydraulic shift valve 272 and the electrohydraulic steering valve 270 are controlled. The shift output adjustment of each of the hydraulic continuously variable transmissions 53 and 54 based on the switching operation is prohibited. If any one of the operation shafts 355 and 356 is manually rotated during execution of the shift steering control, the above-described shift steering control is forcibly terminated, and the main shift lever 43 and the steering handle 11 are terminated. The switching operation of the electrohydraulic shift valve 272 and the electrohydraulic steering valve 270 according to the operation amount is disabled. Then, unless the combine is turned off and then turned on again, the shift steering control is not restored. For this reason, when the operation shafts 355 and 356 are manually operated, the shift output adjustment of the hydraulic continuously variable transmissions 53 and 54 by the electrohydraulic shift valve 272 and the electrohydraulic steering valve 270 coexists. Therefore, the possibility that the hydraulic continuously variable transmissions 53 and 54, and thus the traveling machine body 1 may behave in an unstable manner against the operator's intention can be reliably avoided. It is possible to ensure traveling safety when the operation shafts 355 and 356 are manually rotated.

  As shown in FIG. 10, an oil supply port 365 for supplying hydraulic oil is provided in front of the PTO pulley 119 in the left side surface of the mission case 88 that also functions as a hydraulic oil tank. The oil filler 365 is closed by a detachable oil cap 366. An oil inspection window 367 for visually confirming the amount of hydraulic oil in the mission case 88 from the outside is provided on the left side surface of the mission case 88 at a position below the oil supply port 365 and lower than the PTO pulley 119. . By looking at the oil inspection window 367 at the time of inspection before use or when exchanging the hydraulic oil, it can be easily confirmed whether or not the amount of hydraulic oil in the mission case 88 has reached the height position of the oil inspection window 367. The oil inspection window 367 of the embodiment is located higher than the left gear case 349 and the guard plate 353. When exchanging or replenishing hydraulic oil, the oil supply port 365 and the oil inspection window on the left side surface of the transmission case are opened with the cutting device 3 opened and rotated laterally outward about the vertical axis 300. 367 is exposed. Then, the oil supply cap 366 is opened and closed, and hydraulic oil is supplied from the oil supply port 365 into the mission case 88 while looking at the oil detection window 367 on the same side as the oil supply port 365. As described above, in the embodiment, since the oil supply port 365 is located at a midway height in the vertical direction of the transmission case 88 that also serves as a hydraulic oil tank, the oil level is directly below the oil supply port 365, that is, the maximum oil level indicated by a one-dot chain line in FIG. You can only refuel up to Hm.

  As shown in FIG. 11, a suction filter 368 for filtering hydraulic oil is incorporated in the right side surface of the mission case 88 at a position behind the oil detection window 367 and lower than the PTO pulley 119. The suction filter 368 of the embodiment is located behind and in the vicinity of the right gear case 349 and is configured to filter the hydraulic oil on the bottom side of the mission case 88. Therefore, the oil inspection window 367 and the suction filter 368 are respectively positioned at positions facing each other in the front-rear and left-right directions across the differential mechanism 52 on the lower side inside the mission case 88. The suction filter 368 is connected to a charge pump 251 attached to the outer surface of the hydraulic transmission case via a suction hose 369 extending vertically. The charge pump 251 is configured to be rotationally driven by the pump shaft 59 of the second hydraulic pump 57. The hydraulic oil on the bottom side of the mission case 88 is sucked into the charge pump 251 through the suction filter 368 and the suction hose 369 by the drive of the charge pump 251 and supplied to the oil passages 252, 253, 257, etc. of the hydraulic circuit 250. Is done.

(8). Structure for switching the sub-transmission mechanism Next, a structure for switching the sub-transmission mechanism 51 as a transmission gear mechanism will be described with reference to FIGS. 9, 12, and 13. FIG. As shown in FIG. 12, a dog clutch type sub-shift shifter 64 that can be engaged with and disengaged from the sub-transmission low-speed gear 62 and the sub-transmission high-speed gear 63 is a sub-shift that projects forward from the front surface of the transmission case 88 via a shift fork 470. The operation shaft 471 is linked and connected. In this case, when the auxiliary transmission operation shaft 471 rotates about its axis, the auxiliary transmission shifter 64 slides along the parking brake shaft 65 in conjunction with this and engages with the gears 62 and 63 or both. The engagement with 62, 63 is configured to be released. As a result, the shift output (sub-shift output) from the straight-travel hydraulic continuously variable transmission 53 is selectively switched to a low-speed output, neutral or high-speed output. A switching arm 472 is attached to the protruding end side (front end side) of the auxiliary transmission operation shaft 471. An auxiliary transmission electric motor 475 as a multi-stage transmission actuator is linked to the switching arm 472 via a relay rod 473 with a damper 474 as a damper member.

  In the embodiment, the bracket plate 476 is fixed to the frame of step 357 located on the right side in the traveling direction of the hydraulic transmission case 350. A sub-transmission electric motor 475 that can rotate forward and backward is attached to the bracket plate 476. A cam disk 477 is fixed to the output shaft 475a of the auxiliary transmission electric motor 475. An output arm 478 that integrally rotates about the output shaft 475a is attached to the cam disk 477. One end side of a relay rod 473 with a damper 474 is connected to a free end side (front end side) of the output arm 478 so as to be pivotable by a pivot pin 479 that is laterally oriented in the front-rear direction. The free end side of the switching arm 472 is connected to the other end side of the relay rod 473 with the damper 474 via a pivot pin 480 that is laterally oriented in the front-rear direction. By the forward / reverse rotation of the auxiliary transmission electric motor 475, the auxiliary transmission operation shaft 471 is rotated in the forward / reverse direction via the relay rod 473 with the damper 474, and the auxiliary transmission shifter 64 slides along the parking brake shaft 65. become.

  A low-speed recess 482a, a neutral recess 482b, and a high-speed recess for temporarily engaging and engaging the ball clutch 481 provided on the auxiliary transmission electric motor 475 or the bracket plate 476 are provided on the outer peripheral surface of the cam disk 477. 482c is formed. The rotation of the sub-transmission electric motor 475 (output shaft 475a) is restricted within an angular range in which the ball clutch 481 is fitted in each of the recesses 482a to 482c. A motor rotation angle sensor 483 such as a rotary encoder serving as a first detection unit is provided on the output shaft 475a of the auxiliary transmission electric motor 475. The motor rotation angle sensor 483 is used for the state of the sub-transmission mechanism 51 set by the sub-transmission electric motor 475, that is, for the pressing operation of each switching button 44a to 44c (sub-transmission operation switch 44) as a transmission operation body. This is for detecting a corresponding target switching state (low speed output, neutral or high speed output). On the other hand, the auxiliary speed change operation shaft 471 or the switching arm 472 is provided with an arm rotation angle sensor 484 such as a rotary encoder as second detection means. The arm rotation angle sensor 484 is for detecting the state of the subtransmission mechanism 51 by the push-pull operation of the relay rod 473 with the damper 474, that is, the actual switching state of the subtransmission mechanism 51. Both the rotation angle sensors 483 and 484 are electrically connected to a shift steering controller 400 described later. The detection information is appropriately input to the shift steering controller 400.

  A spring 485 is incorporated in a damper 474 provided in the middle of the relay rod 473. When the operation force from the sub-transmission electric motor 475 is smaller than a predetermined amount, the length of the relay rod 473 is expanded and contracted by using elastic deformation of the spring 485, thereby absorbing the unnecessary operation force and sub-transmission. The mechanism 51 is configured to prevent malfunction. In particular, in the embodiment, the damper 474 has a shift movement distance of one step in the sub-transmission direction 51, that is, within the range of the low-to-neutral and neutral-to-high speed movement distance l (arc length) in the switching arm 472. The expansion / contraction stroke L (extraction / contraction allowance) of the spring 485 is changed.

(9). Next, the shift steering control of the combine (traveling machine body 1) will be described with reference to FIGS. A shift steering controller 400 as a control means mounted on the traveling machine body 1 includes detection information of a main shift sensor 401 that detects an operation amount of the main shift lever 43 and a steering angle sensor 402 that detects a steering angle of the steering handle 11. Based on this, the shift operation control for adjusting the vehicle speed and the traveling direction of the traveling machine body 1 is performed by switching the electrohydraulic shift valve 272 and the electrohydraulic steering valve 270. That is, in the embodiment, the mechanical transmission structure is not provided between the main transmission lever 43 and the steering handle 11 and the two hydraulic continuously variable transmission mechanisms 53 and 54, and the steer-by-wire that electrically controls between them. The shift control of the system is executed. Although not shown in detail, the shift steering controller 400 includes a CPU that executes various arithmetic processes and controls, an EEPROM that stores control programs and data, a flash memory, a RAM that temporarily stores control programs and data, and It has an input / output interface.

  On the input side of the shift steering controller 400, a main shift sensor 401 that detects at least the amount of operation of the main shift lever 43, a steering angle sensor 402 that detects the steering angle of the steering handle 11, a low-speed output of the sub-shift output, neutral or Sub-shift switch 44 (low-speed switch button 44a, neutral switch button 44b and high-speed switch button 44c) for selectively switching to high-speed output, threshing switch 403 for detecting the on / off state of threshing clutch 161, mowing shift operating means (mowing) A cutting switch 404 for detecting the operation state of the shift clutch), an engine rotational speed sensor 405 for detecting the rotational speed of the engine 14 (camshaft position of the output shaft 150), and the rotational speed (straight forward vehicle speed) of the first hydraulic motor 56. , Sub-shift output gear 67 output), that is, straight travel for detecting the shift output amount of the straight-running hydraulic continuously variable transmission 53 Pickup rotation sensor 93 (straight vehicle speed sensor), steering pickup rotation sensor 95 for detecting the rotational speed (turning vehicle speed) of the steering output of the second hydraulic motor 58, that is, the shift output amount of the hydraulic continuously variable transmission 54 for turning. A turning vehicle speed sensor), a motor rotation angle sensor 483 for detecting a target switching state corresponding to a pressing operation of each of the switching buttons 44a to 44c (sub-transmission operation switch 44), and an arm for detecting an actual switching state of the sub-transmission mechanism 51. A rotation angle sensor 484 and the like are connected.

  On the output side of the shift steering controller 400, at least the electromagnetic hydraulic shift valve 272 as an electric actuator for operating the shift cylinder 273 for the swash plate 55a of the first hydraulic pump 55, and the swash plate 57a of the second hydraulic pump 57. An electro-hydraulic steering valve 270 as an electric actuator for operating the steering cylinder 271, a cutting gear shift valve 282 for operating the cutting gear shift cylinder 280, a cutting constant speed valve 283 for operating the cutting constant speed cylinder 281, and a threshing clutch 161 are provided. An electric motor 175 for threshing clutch that is turned on and off, an electric motor 475 for auxiliary transmission that switches the auxiliary transmission mechanism 51, and the like are connected.

  In response to manual operation of the main shift lever 43, the electrohydraulic shift valve 272 is electrically switched to operate the shift cylinder 273 to change the angle of the swash plate 55a of the first hydraulic pump 55. A traveling speed change operation (forward / reverse switching operation) is performed in which the rotational speed of the linear motor shaft 60 of the hydraulic motor 56 is steplessly changed or reversed. Further, by electrically switching the electrohydraulic steering valve 270 in response to the manual operation of the steering handle 11, the steering cylinder 271 is operated to change the swash plate 57a angle of the second hydraulic pump 57. The left and right steering operation for changing the rotation speed of the turning motor shaft 61 of the second hydraulic motor 58 steplessly or reversely is performed, the direction of travel is changed to the left and right, and the direction is changed at the field headland. Correct the course. Furthermore, the steering brake 79 maintains the turning motor shaft 61 in the stopped state (non-rotatable state) by the neutral operation (straight forward maintaining operation) of the steering handle 11 and the neutral operation of the subtransmission mechanism 51, and the second hydraulic motor 58. Is stopped and turning output is stopped.

  In the shift steering control shown in the flowchart of FIG. 15, the shift steering controller 400 reads the detected values of the main shift sensor 401, the steering angle sensor 402, and the sub shift switch 44 (S1), and neutralizes the sub shift switch 44. If so (S2: YES), turn output stop control is performed to brake the steering brake 79 and stop the second hydraulic motor 58 (S3). If the sub-shift switch 44 is operated other than neutral (S2: NO), it is then determined whether or not the main shift lever 43 is in the neutral position (S4). If the main shift lever 43 is in the neutral position (S4: YES), the aforementioned turning output stop control (S3) is executed. If the main shift lever 43 is operated to a position other than the neutral position (S4: NO), then the steering angle of the steering handle 11 is determined (S5), and if the steering handle 11 is in the neutral position (straight forward maintaining position) ( (S5: YES), the electrohydraulic shift valve 272 is electrically switched in accordance with the amount of operation of the main shift lever 43, and the shift travel control is performed for causing the traveling machine body 1 to travel straight forward or backward (S6). . If the steering handle 11 is operated to a position other than neutral (S5: NO), the electrohydraulic steering valve 270 is electrically switched in accordance with the amount of operation of the main transmission lever 43 and the steering handle 11 to travel. Left and right steering control for changing the traveling direction of the machine body 1 to the left and right is executed (S7). If any one of the operation shafts 355 and 356 is manually rotated during execution of steps S3, S6, or S7 (S8: YES), the shift steering controller 400 forces the above-described shift steering control. In step S9, the switching operation of the electrohydraulic shift valve 272 and the electrohydraulic steering valve 270 according to the operation amount of the main shift lever 43 and the steering handle 11 is disabled.

  An example of the switching control of the auxiliary transmission mechanism 51 will be described with reference to the flowchart of FIG. The shift steering controller 400 of the embodiment is set so as to execute not only the shift steering control described above but also the switching control of the auxiliary transmission mechanism 51 described below. The switching control of the subtransmission mechanism 51 is interrupted when, for example, the switching buttons 44a to 44c are pressed. In this case, as shown in FIG. 16, after reading the detected value of the auxiliary transmission switch 44, that is, which switching button 44a to 44c is operated (S11), the detection information of the straight-ahead pickup rotation sensor 93 is It is determined whether or not the linear output of the hydraulic motor 56 is stopped (whether the output is zero) (S12).

  If there is a straight output from the first hydraulic motor 56 (S12: NO when the straight-travel motor shaft 60 is rotating), the sub-transmission electric motor 475 is not operated and the process returns. When the straight-ahead output of the first hydraulic motor 56 is stopped (S12: YES), the output arm 478 that rotates integrally with the output shaft 475a by driving the sub-transmission electric motor 475 is switched to each switching button 44a-. 44c (sub-shift operation switch 44) is rotated to a position corresponding to the pressing operation (S13). Then, the relay rod 473 with the damper 474 is pushed and pulled, and the auxiliary transmission operation shaft 471 is rotated via the switching arm 472, and the transmission position (low speed, neutral or neutral) corresponding to the pressing operation of each switching button 44a to 44c. The auxiliary transmission shifter 64 is slid and moved at a high speed.

  Next, based on the detection information of the motor rotation angle sensor 483 and the arm rotation angle sensor 484, the sub-transmission operation shaft 471 or the switching arm 472 actually shift positions (low speeds) corresponding to the pressing operation of the switching buttons 44a to 44c. , Neutral or high speed) (S14), and when the detection information of the motor rotation angle sensor 483 and the arm rotation angle sensor 484 match, that is, the sub-transmission operation shaft 471 or the switching arm. When 472 is actually at the shift position corresponding to the pressing operation of each of the switching buttons 44a to 44c (S14: YES), the sub-shift shifter 64 is slid to the correct shift position. The switching operation of the mechanism 51 is completed (S15). When the detection information of both rotation angle sensors 483 and 484 do not match (S14: NO), for example, the meshing of the dog clutch type sub-shift shifter 64 is out of phase and cannot move, and the sub-shift shifter 64 It can be locked. In this state, since the auxiliary transmission operation shaft 471 or the switching arm 472 is out of the transmission position corresponding to the pressing operation of the switching buttons 44a to 44c, the damper 474 of the relay rod 473 is elastically deformed to expand and contract. . In such a case, the electrohydraulic shift valve 272 constituting the hydraulic servo mechanism 277 for shifting gears is electrically switched so that a predetermined minute amount of output is output to the linear motor shaft 60 of the first hydraulic motor 56. To output once (only for a minute time) (S16), and return to step S14. Here, the predetermined minute amount of output is assumed to be, for example, rotational power slightly exceeding the backlash (backlash) of the straight transmission gear mechanism 50.

  Once the predetermined minute amount of output is output from the linear motor shaft 60 of the first hydraulic motor 56, the minute speed output is transmitted to the sub transmission mechanism 51 in a state where the sub transmission shifter 64 is locked. For this reason, the auxiliary transmission shifter 64 is unlocked, and the rotational torque confined in the auxiliary transmission mechanism 51 is also released. Thereafter, due to the elastic restoring force of the damper 474 in the middle of the relay rod 473, the auxiliary transmission operation shaft 471 or the switching arm 472 rotates and moves to the transmission position corresponding to the pressing operation of the switching buttons 44a to 44c. As a result, the sub-shift shifter 64 slides to the aforementioned shift position. If the locked state of the auxiliary transmission shifter 64 is relatively loose, the auxiliary transmission shifter 64 is unlocked only by the elastic restoring force of the damper 474 in the middle of the relay rod 473 and confined in the auxiliary transmission mechanism 51. The released rotational torque can be released together.

  As apparent from the above description and FIGS. 9 and 13, the hydraulic continuously variable transmission 53 that transmits the power of the engine 14 mounted on the traveling machine body 1 to the transmission gear mechanism 51, and the hydraulic continuously variable transmission 53 A work vehicle including a continuously variable transmission actuator 277 for adjusting a transmission output, and a multi-stage transmission actuator 475 for switching the transmission gear mechanism 51 to a transmission position selected by the transmission operation body 44. Since the switching arm 472 associated with the transmission gear mechanism 51 and the multi-stage transmission actuator 475 are interlocked and connected via damper members 473 and 474, the transmission gear is driven by the multi-stage transmission actuator 475. The mechanism 51 can be switched smoothly. For this reason, the operator can perform the switching operation of the transmission gear mechanism 51 with a light operation force, and the operation burden on the operator is reduced. Particularly in this case, since the damper members 473 and 474 are interposed between the switching arm 472 and the multi-stage transmission actuator 475, for example, even when the transmission gear mechanism 51 is locked so as not to be switched, If the degree of lock is relatively loose, the lock can be released and the rotational torque confined in the transmission gear mechanism 51 can be released only by the elastic restoring force of the damper members 473, 474, and the transmission gear can be reliably engaged. The mechanism 51 can be switched.

  As is apparent from the above description and FIGS. 9, 13, 14, and 16, the first detecting means 483 that detects the operating state of the multi-stage transmission actuator 475 and the first detecting unit 483 that detects the operating state of the switching arm 472. 2 detection means 484, and when the detection information of both detection means 483 and 484 coincides, the switching operation of the transmission gear mechanism 51 to the transmission position is completed. The transmission gear mechanism 51 can be appropriately switched by double checking by the detection means 483 and 484, and thereafter, the power can be smoothly transmitted from the hydraulic continuously variable transmission 53 to the transmission gear mechanism 51.

  As is apparent from the above description and FIGS. 9, 13, 14 and 16, when the detection information of both the detection means 483, 484 does not match, the hydraulic continuously variable transmission 53 to the transmission gear mechanism 51. For example, even when the transmission gear mechanism 51 is locked so as not to be switched, the output of the predetermined minute amount is output to the transmission gear mechanism 51. , The rotational torque confined in the transmission gear mechanism 51 can be released by releasing the lock. Therefore, regardless of whether the transmission gear mechanism 51 is locked or not, the transmission gear mechanism 51 can be switched more reliably.

  As is apparent from the above description and FIGS. 9, 13, 14 and 16, when the shift output of the hydraulic continuously variable transmission 53 is zero, the multi-stage shift actuator is selected by the selection operation of the shift operation body 44. 475 is operated, and the transmission gear mechanism 51 is configured to switch to the transmission position corresponding to the transmission operation body 44, so that the transmission output is output from the hydraulic continuously variable transmission 53. There is no possibility that the transmission gear mechanism 51 is switched, and it is possible to prevent the vehicle speed (traveling speed) of the traveling machine body 1 from changing suddenly. In addition, engine troubles due to sudden load fluctuations can be suppressed.

  As is apparent from the above description and FIGS. 9 and 13, the expansion / contraction stroke L of the damper members 473, 474 is changed within the range of the shift movement distance l of one step in the transmission gear mechanism 51. Therefore, the length of the damper members 473 and 474 can be expanded and contracted by elastic deformation to absorb unnecessary operation force, and malfunction of the transmission gear mechanism 51 can be prevented.

  The present invention is not limited to the above-described embodiment, and can be embodied in various forms. For example, the present invention is not limited to the above-described combine, but can be widely applied to various work vehicles such as farm work machines such as tractors and rice transplanters and special work vehicles such as crane cars. In addition, the structure of each part is not limited to embodiment of illustration, A various change is possible in the range which does not deviate from the meaning of this invention.

DESCRIPTION OF SYMBOLS 1 Traveling machine body 14 Engine 53 Hydraulic advance continuously variable transmission 272 Electrohydraulic shift valve 273 Shift cylinder 277 Hydraulic servo mechanism (continuously variable actuator)
472 Switching arm 473 Relay rod 474 Damper 475 Sub-shifting electric motor (multi-stage shifting actuator)
483 Motor rotation angle sensor (first detection means)
484 Arm rotation angle sensor (second detection means)

Claims (5)

A work vehicle comprising: a continuously variable transmission that transmits power of a prime mover mounted on a traveling machine body to a transmission gear mechanism; and a continuously variable transmission actuator for adjusting a shift output of the continuously variable transmission;
A multi-stage transmission actuator for switching the transmission gear mechanism to a transmission position selected by a transmission operation body is provided, and a switching arm associated with the transmission gear mechanism and the multi-stage transmission actuator are interlocked via a damper member. Connected,
Work vehicle. A first detecting means for detecting an operating state of the multi-stage speed change actuator; and a second detecting means for detecting an operating state of the switching arm. Configured to complete the switching operation of the transmission gear mechanism to a position;
The work vehicle according to claim 1. When the detection information of both the detection means does not match, it is configured to once output a predetermined minute amount from the continuously variable transmission toward the transmission gear mechanism.
The work vehicle according to claim 2. When the shift output of the continuously variable transmission is zero, the multi-stage shift actuator is activated by the selection operation of the shift operation body, and the transmission gear mechanism is switched to the shift position corresponding to the shift operation body. Configured to,
The work vehicle described in any one of Claims 1-3. The expansion / contraction stroke of the damper member is changed within a range equal to or less than the shift movement distance for one step in the transmission gear mechanism.
The work vehicle according to any one of claims 1 to 4.

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