JP2008196649A - Work vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a work vehicle equipped with a detector capable of correctly detecting forward/backward changeover of a running machine body, and easily installable. <P>SOLUTION: This work vehicle is provided with: a transmission 14 carrying out forward/backward changeover of the running machine body 3 by changing gears 23a, 23b, 41a, 41b and 42 gearing with each other by reciprocative operation of a shaft rod; a shift arm 82 reciprocatively operating the shift rod; a forward/backward changeover operation means 11 connected to the shift arm 82 through a linkage mechanism 84; and the detector 79 detecting the forward/backward changeover of the transmission 14. In the work vehicle, the shift arm 82 is arranged in the outside of the transmission 14; the detector 79 is arranged on a shift arm shaft 86 of the shift arm 82; and the front/backward changeover of the running machine body is detected by sensing at least two rotating positions such as a forward changeover position and a backward changeover position of the shift arm shaft 86 by the detector 79. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a work vehicle including a detection device that detects forward / backward switching of a traveling machine body.

Patent Document 1, which includes a transmission that mechanically performs forward / reverse switching of the traveling machine body and a detection device that detects forward / backward switching of the transmission in order to use information on the forward / reverse switching of the traveling machine body for various controls. The work vehicle shown in 2 is known.
Japanese Patent Laid-Open No. 2001-121985 JP 2002-257202 A

  However, since the work vehicle shown in Patent Document 1 is provided with a detection device for the forward / reverse switching operation tool for switching the forward / backward movement of the traveling machine body, there is a backlash or the like in the linkage mechanism that connects the forward / backward switching operation tool and the transmission. If so, there is a problem that the forward / reverse switching of the traveling aircraft cannot be accurately detected.

  On the other hand, the work vehicle shown in Patent Document 2 is provided with a detection device on a shift rod of a transmission that changes the meshing gear by reciprocating operation and performs forward / reverse switching of the traveling machine body. However, since it is necessary to provide a detection device inside the transmission, there is a drawback that it is necessary to process the transmission itself.

  In order to solve the above-described problem, the work vehicle of the present invention includes a transmission 14 for changing the gear 23a, 23b, 41a, 41b, 42 engaged by reciprocating operation of a shift rod and switching the traveling body 3 forward and backward. A shift arm 82 for reciprocating the shift rod, a forward / reverse switching operation tool 11 connected to the shift arm 82 via a linkage mechanism 84, and a detection device 79 for detecting forward / backward switching of the transmission 14. In the work vehicle provided, the shift arm 82 is provided outside the transmission 14, the detection device 79 is provided on the shift arm shaft 86 of the shift arm 82, and the detection device 79 is connected to the forward switching position and the reverse switching position of the shift arm shaft 86. It is characterized by detecting at least two rotational positions.

  Second, the detection device 79 includes a detection arm 91 that rotates together with the shift arm shaft 86, and forward / reverse switching detection switches 92 and 93 that are turned on and off by the detection arm 91.

  Thirdly, the detection device 79 is provided with a neutral switch 94 for detecting the neutral position of the shift rod, and the detection switch 94 is turned on and off as the shift arm shaft 86 rotates.

  According to the work vehicle of the present invention configured as described above, since the shift arm for operating the shift rod is provided outside the transmission and the detection device is provided on the shift arm shaft of the shift arm, the transmission itself is not processed. Since the detection device can be provided directly on the shift arm shaft of the shift arm, the forward and backward travel of the traveling machine body can be performed more accurately than the detection unit provided in the forward / reverse switching operation tool for operating the shift arm. Switching can be detected.

  Further, by configuring the detection device so as to detect the neutral position of the shift rod, it is possible to detect forward / reverse switching of the transmission even if either forward switching or reverse switching cannot be detected due to a failure or the like.

  FIG. 1 is an overall side view of a tractor to which a work vehicle of the present invention is applied. The tractor includes a traveling machine body 3 having a front wheel 1 and a rear wheel 2, a driver seat 4 provided in the center of the traveling machine body 3, a cabin 6 covering the driver seat 4, and a link mechanism 7 at the rear of the traveling machine body 3. And a working machine (not shown) such as a rotary cultivator that is connected to be movable up and down.

  2 and 3 are a side view and a plan view of a driver's seat in the cabin. The driver's seat 4 includes a seat 8 on which an operator is seated, a travel shift lever 9 provided on the left side of the seat 8, a forward / reverse switching lever 11 (front / rear switching operation tool) and a clutch pedal 12 provided in front of the seat 8. And.

  The sub-transmission unit 29 (see FIG. 4) of the transmission 14 is switched in three stages of neutral, high speed and neutral by the forward / backward swing operation of the travel shift lever 9, and the shift up switch 9a provided on the travel shift lever 9 and the shift The down switch 9b (see FIG. 6) switches the speed of the main transmission 47 (see FIG. 4) of the transmission 14 in eight steps.

  FIG. 4 is a power transmission system diagram of the tractor. The power of the engine 13 is transmitted to the front wheels 1, the rear wheels 2, and the PTO shaft 16 that drives the work machine via the transmission 14. Hereinafter, the power transmission means to the front wheel 1 and the rear wheel 2 will be described in detail.

  The power of the engine 13 is transmitted to the transmission shaft 18 via the clutch 17 that is turned on and off by the clutch pedal 12 described above, and the power of the transmission shaft 18 is transmitted to the travel shaft 21 through the first main transmission 19. The power of the traveling shaft 21 is transmitted to the switching shaft 23 via the main clutch 22, and the power of the switching shaft 23 is transmitted to the main transmission shaft 26 via the forward / reverse switching portion 24 that performs forward / backward switching of the traveling body 3. The power of the main transmission shaft 26 is transmitted to the auxiliary transmission shaft 28 through the second main transmission unit 27, and the power of the auxiliary transmission shaft 28 is transmitted to the drive shaft 31 through the auxiliary transmission unit 29. The power of the drive shaft 31 is transmitted to the rear wheel 2 through the differential gear 32 and the like, and is also transmitted to the front wheel drive shaft 33. The power transmitted to the front wheel drive shaft 33 is transmitted to the front wheel 1 via the quick turn device 34 and the differential gear 36 for the front wheel 1.

  The first main transmission unit 19 includes four input gears 18a, 18b, 18c, and 18d that are integrally fixed to the transmission shaft 18, and four output gears that always mesh with the corresponding input gears 18a, 18b, 18c, and 18d. 37a, 37b, 37c, and 37d. The output gears 37a, 37b, 37c, and 37d are rotatably supported on the traveling shaft 21.

  Between the two output gears 37a and 37b close to the engine 13, there is provided a shift member 38 for selectively fixing one of the output gears 37a and 37b to the traveling shaft 21 by a synchromesh method. When the member 38 is in a position (neutral position, neutral position) between the two gears 37a and 37b, the rotation of the two gears 37a and 37b cannot be transmitted to the traveling shaft.

  A shift member 39 having substantially the same configuration as the shift member 38 is also provided between the two output gears 37c and 37d far from the engine, and the rotation of either one of the gears 37c and 37d is selectively performed. It is transmitted to the traveling shaft 21.

  Then, the two shift members 38, 39 operate so that two or more of the four output gears 37a, 37b, 37c, 37d are not fixed to the traveling shaft 21 at the same time, and the four input gears 18a, 18b. , 18c, 18d is transmitted to the traveling shaft 21 through the corresponding output gears 37a, 37b, 37c, 37d at different gear ratios. For this reason, the first main transmission unit 19 transmits the power of the transmission shaft 18 to the traveling shaft 21 in four stages.

  The main clutch 22 is a hydraulic clutch installed to turn on and off the power transmitted from the traveling shaft 21 to the switching shaft 23.

  The forward / reverse switching unit 24 includes two input gears 23 a and 23 b that are integrally fixed to the switching shaft 23, two output gears 41 a and 41 b that are rotatably supported by the main transmission shaft 26, and an intermediate gear 42. And. While the input gear 23b on the side far from the engine 13 and the output gear 41b always mesh with each other, the rotation of the input gear 23a on the near side from the engine 13 always meshes with the input gear 23a and the output gear 41a on the near side from the engine 13. It is transmitted to the output gear 41a by the mating intermediate gear 42. With the above configuration, the rotation directions of the two output gears 41a and 41b are reversed.

  Between the two output gears 41a and 41b, a shift member 43 having substantially the same configuration as the shift member 38 described above is provided, and either one of the powers of the two output gears 41a and 41b is selectively used as a main power. It is transmitted to the transmission shaft 26. As described above, the forward / reverse switching unit 24 switches the rotational direction of the main transmission shaft 26 to perform forward / backward switching of the traveling machine body 3.

  The second main transmission unit 27 includes two input gears 44 a and 44 b that are rotatably supported on the main transmission shaft 26, and two output gears 28 a and 28 b that are integrally fixed to the auxiliary transmission shaft 28. The input gears 44a and 44b are always meshed with the corresponding output gears 28a and 28b. Between the two input gears 44a and 44b, a shift member 46 having substantially the same configuration as the shift member 38 described above is provided. The power of the main transmission shaft 26 is selectively transmitted to one of the two input gears 44a and 44b by the shift member 46, and is transmitted to the auxiliary transmission shaft 28 via the corresponding output gears 28a and 28b. .

  Further, the input gears 44a and 44b and the output are set so that the gear ratio is different between when one of the two input gears 44a and 44b is fixed to the main transmission shaft 26 and when the other is fixed to the main transmission shaft 26. The number of teeth of the gears 28a and 28b is set. The second main transmission unit 27 and the first transmission unit 19 described above constitute a main transmission unit 47 that transmits power in eight steps.

  The auxiliary transmission unit 29 includes two input gears 28c and 28d fixed integrally to the auxiliary transmission shaft 28, two intermediate gears 48a and 48b that always mesh with the corresponding input gears 28c and 28d, and a corresponding intermediate gear. Two output gears 49a and 49b that always mesh with 48a and 48b are provided. The intermediate gears 48 a and 48 b are rotatably supported on the front wheel drive shaft 33, and the output gears 49 a and 49 b are rotatably supported on the drive shaft 31.

  Between the two output gears 49a and 49b, a shift member 51 having substantially the same configuration as that of the shift member 38 described above is provided, and either one of the powers of the two output gears 49a and 49b is transmitted by the shift member 51. It is selectively transmitted to the drive shaft 31. Further, the input gears 28c and 28d and the intermediate gears 48a and 48b are different so that the gear ratio is different when one of the two output gears 49a and 49b is fixed to the drive shaft 31 and when the other is engaged with the drive shaft 31. And the number of teeth of the output gears 49a and 49b is set.

  The power of the drive shaft 31 is transmitted to the front wheel drive shaft 33 via a front wheel drive gear 52 fixed integrally to the drive shaft 31 and a switching gear 53 that rotates integrally with the front wheel drive shaft 33. The switching gear 53 includes a small-diameter gear 53a that meshes with the front-wheel drive gear 52 and a large-diameter gear 53b, and is supported by the front-wheel drive shaft 33 so as to be movable in the axial direction.

  By moving the switching gear 53 in the axial direction of the front wheel driving shaft 33, the front wheel driving gear 52 and the switching gear 53 can be engaged and disengaged. When the front wheel drive gear 52 and the switching gear 53 are engaged, the traveling machine body 3 becomes four-wheel drive, and when the engagement between the front wheel drive gear 52 and the switching gear 53 is released, the traveling machine body 3 becomes two-wheel drive.

  In addition to the switching gear 53, an output gear 33a is integrally fixed to the front wheel drive shaft 33. The quick turn device 34 selectively transmits the rotation of either the large-diameter gear 53 b of the switching gear 53 or the output gear 33 a to the differential gear 36 for the front wheel 1.

  The power transmission means from the engine 13 to the front wheels 1 and the rear wheels 2 has been described above. Next, the operation means for the forward / reverse switching unit 24, the auxiliary transmission unit 29, the main transmission unit 47, and the main clutch 22 of the transmission 14 will be described. To do.

  In the forward / reverse switching portion 24, a shift member 43 is engaged with a shift rod (not shown) provided so as to be capable of reciprocating in the transmission 14. The shift rod has a position where one of the two output gears 41 a and 41 b is fixed to the main transmission shaft 26 and the other of the two output gears 41 a and 41 b to the main transmission shaft 26 by reciprocating operation or the like. Gears (input gears 23a and 23b, output gears 41a and 41b, intermediate gears 42) for transmitting power from the switching shaft 23 to the main transmission shaft 26 side are moved to either the fixed position or the neutral position. ).

  The shift rod is mechanically coupled to the aforementioned forward / reverse switching lever 11 via a shift arm 82 and a linkage mechanism 84 (see FIGS. 7 and 8) described later. Then, by the forward / backward swing operation of the forward / reverse switching lever 11, the shift rod is moved to any one of the forward switching position, the reverse switching position, or the neutral position, and the forward / backward switching and neutral switching of the traveling machine body 3 are performed.

  In the sub-transmission unit 29, the shift member 51 is mechanically connected to the above-described travel shift lever 9, and the shift member 51 is operated by swinging the travel shift lever 9 back and forth so that the low-speed state and the neutral state are achieved. Then, the traveling machine body 3 is switched to either the high speed state.

  The main transmission 47 and the main clutch 22 are operated by a hydraulic control device 54. FIG. 5 is a hydraulic circuit diagram of the hydraulic control device. The hydraulic control measure 54 includes an electromagnetic proportional valve 56 that is a proportional pressure control solenoid valve that performs an operation of engaging the main clutch 22, a first direction switching valve 57, a second direction switching valve 58, and a third direction switching valve that are solenoid valves. 59, the fourth direction switching valve 61 and the fifth direction switching valve 62, the hydraulic cylinder 63 hydraulically controlled by the first direction switching valve 57 and the second direction switching valve 58, the third direction switching valve 59 and the fourth direction. A hydraulic cylinder 64 that is hydraulically controlled by a switching valve 61, a hydraulic cylinder 66 that is hydraulically controlled by a fifth direction switching valve 62, a pressure sensor 67 that measures internal pressure, and an oil temperature sensor 68 that measures internal temperature. The hydraulic oil is fed into the hydraulic control device 54 by the oil pump 69.

  The electric proportional valve 56 engages and operates the main clutch 22, which is a hydraulic clutch, and connects the traveling shaft 21 and the switching shaft 23.

  The first direction switching valve 57 and the second direction switching valve 58 extend and contract the corresponding shift piston 63 a of the hydraulic cinder 63. The shift piston 63a is engaged with a shift member 38 provided between the two output gears 37a, 37b on the side close to the engine of the first main transmission unit 19, and the shift member 38 has two outputs. One of the gears 37a and 37b is fixed to the traveling shaft 21, and the other one of the two output gears 37a and 37b is fixed to the traveling shaft 21, and the neutral position is moved. A check valve 71 is connected to the shift piston 63a, and the check valve 71 operates to disconnect the main clutch 22 by reducing the hydraulic pressure on the main clutch 22 side while the shift member 38 is operating. To do.

  The third direction switching valve 59 and the fourth direction switching valve 61 extend and contract the corresponding shift piston 64a of the hydraulic cinder 64. The shift piston 64a is engaged with a shift member 39 provided between the two output gears 37c, 37d on the side far from the engine of the first main transmission unit 19, and the shift member 39 has two outputs. The gear 37c, 37d is moved to one of a position for fixing the transmission shaft, a position for fixing the other of the two output gears 37c, 37d to the transmission shaft, and a neutral position. A check valve 72 having substantially the same configuration as that of the check valve 71 is also connected to the shift piston 64a.

  The fifth direction switching valve 62 expands and contracts the corresponding shift piston 66a of the hydraulic cinder 66. The shift piston 66a is engaged with the shift member 46 of the second main transmission unit 27, and the shift member 46 is fixed at one of the two input gears 44a and 44b to the main transmission shaft 26, and 2 Positioning operation is performed to either one of the positions where the other of the two input gears 44 a and 44 b is fixed to the main transmission shaft 26. Also connected to the shift piston 66a is a check valve 73 having substantially the same configuration as the check valve 71 described above.

  As described above, the first directional switching valve 57, the second directional switching valve 58, the third directional switching valve 59, the fourth directional switching valve 61, and the fifth directional switching valve that change the main transmission 47 in eight steps. 62 is operated by an electrical signal output from the control device 70 in response to the on / off operation of the shift-up button 9a and the shift-down button 9b.

  FIG. 6 is a block diagram of the control device. In the control device 70, an electromagnetic proportional valve 56, a first direction switching valve 57, a second direction switching valve 58, a third direction switching valve 59, a fourth direction switching valve 61 and a fifth direction switching valve 62 are connected on the output side. ing. On the other hand, on the input side, the above-described shift-up switch 9a, shift-down switch 9b, pressure sensor 67, and oil temperature sensor 68 are connected, an engine rotation sensor 74 that detects the rotation of the engine 13, and a traveling machine body. 3, an axle rotation sensor 76 that detects the rotation of the front and rear wheels 1, 2, a forward / reverse sensor 77 that detects forward / backward switching of the traveling body 3, and a main clutch sensor 78 that senses the on / off state of the main clutch 22. It has been.

  With the control device 70 having the above configuration, the oil temperature and the hydraulic pressure in the hydraulic control device 54 are kept optimal, while the rotation of the engine 13, the rotation of the front and rear wheels 1 and 2 of the traveling machine body 3, the forward / reverse switching of the traveling machine body 3, While sensing the on / off state of the clutch 22, the shift changing operation of the main transmission unit 47 and the on / off operation of the main clutch 22 are performed.

  Next, the forward / reverse sensor will be described. The forward / reverse sensor 77 is composed of two forward / reverse switching detection switches 92 and 93 provided in the detection device 79 (see FIG. 9). 7 and 8 are a side view and a plan view of the inside of the tractor with the detection device removed. A shift arm 82 that reciprocates the shift rod described above is rotatably supported on the upper surface of the transmission case 81 that covers the transmission 14. The shift arm 82 is connected to the forward / reverse switching lever 11 via a linkage mechanism 84 composed of a wire 83 or the like, and the shift arm 82 is rotated by the forward / backward swing operation of the forward / backward operation lever 11.

  A shift arm shaft 86, which is a rotation shaft of the shift arm 82, protrudes upward from the mission case 81 and rotates integrally with the shift arm 82. On the side peripheral surface of the shift arm shaft 86, two engaging pins 87, 87 that are substantially symmetrical with each other with respect to the shift arm shaft 86 in a plan view are projected in the horizontal direction. 87 and 87 are constituted by spring pins which can be elastically deformed.

  The detection device 79 is attached so as to cover the upper end portion of the shift arm shaft 86 having the above configuration. FIG. 9 is a perspective view of the lower surface side of the detection device. The detection device 79 includes a substantially rectangular parallelepiped-shaped cover body 88 that is open on the lower side, a cylindrical part 89 that is rotatably supported on the inner surface side of the cover body 88 and that is open on the lower side, and an outer side surface of the cylindrical part 89. Plate-like and horizontal detection arm 91 projecting integrally toward the direction, forward switching detection switch 92 (forward / reverse switching detection switch) and reverse switching detection switch 93 (forward / backward) Decimal switch detection switch).

  The cylindrical portion 89 has an inner diameter that is substantially the same as the outer diameter of the upper end portion of the shift arm shaft 86, and is configured so that the upper end portion of the shift arm shaft 86 can be fitted from below. Corresponding to the positions of the engaging pins 87 and 87 when the shift arm shaft 86 is fitted in the cylindrical portion 89, two axial cutouts in the lower side of the cylindrical peripheral portion 88 are opened. Portions 89a and 89a are cut out.

  Each notch portion 89a is configured such that when the upper end portion of the shift arm shaft 86 is fitted into the cylindrical portion 89, the side peripheral surface of the corresponding engagement pin 87 of the shift arm 82 is fitted. The shift arm shaft 86 and the detection arm 91 are integrally rotated by the engagement between the engagement pin 87 of 86 and the notch 89 a of the cylindrical portion 89 of the detection device 79.

  10 and 11 are a side view and a plan view of the inside of the tractor with the detection device attached. As described above, the shift arm shaft 86 is fitted into the cylindrical portion 89 of the detection device 79 so that the upper end portion of the shift arm shaft 86 is covered with the detection device 79 and extended to the lower end of the cover body 88 of the detection device 79. The two mounting seats 88a and 88a are bolted inside the traveling machine body 3 to fix the detection device 79.

  When the detection device 79 is attached to the shift arm shaft 86, the base end portions of the shift arm shaft 86 and the shift arm 82 are covered with the detection device 79, while the middle portion and the distal end portion of the shift arm 82 are covered with the detection device 79. Exposed outside. For this reason, openings 88b and 89b are respectively provided on the side peripheral surfaces of the cover body 88 and the cylindrical portion 89 of the detection device 79 on the shift arm 82 side, and the cover body 88 and the cylindrical portion 89 are rotated by the rotation of the shift arm 82. It is formed in a shape that does not hinder movement.

  FIG. 12A is a bottom view of the detection device when the shift rod is moved to the reverse switching position, and FIG. 12B is a bottom view of the detection device when the shift rod is moved to the neutral position. C) is a bottom view of the detection device when the shift rod is moved to the forward switching position. In the detection device 79, when the shift rod is moved to the reverse switching position by the forward / reverse switching lever 11 and the reverse switching operation of the traveling machine body is performed, the reverse switching detection switch 93 is turned on by the detection arm 91 to be turned on. On the other hand, the forward switching detection switch 92 is turned off to be turned off (see FIG. 12A).

  When the shift rod is moved to the neutral position by the forward / reverse switching lever 11 and the power of the switching shaft 23 of the transmission 14 is not transmitted to the main transmission shaft 26 (the traveling vehicle body 3 is in the neutral state), the forward switching detection switch 92 and The reverse switch detection switch 93 is turned off, and the forward switch detection switch 92 and the reverse switch detection switch 93 are turned off (see FIG. 12B).

  When the shift rod is moved to the forward switching position by the forward / reverse switching lever 11 and the forward switching operation of the traveling machine body 3 is performed, the forward switching detection 92 switch is turned on by the detection arm 82 and turned on, and the reverse switching detection switch 93 is turned off and turned off (see FIG. 12C). As described above, the two forward / reverse switching detection switches 92 and 93 are turned on / off, and the control device 70 is driven by the signal from the forward / backward sensor 77 constituted by the two forward / backward switching detection switches 92 and 93. 3 forward / reverse switching can be detected.

  In this tractor, when the reverse switching of the traveling machine body 3 is detected by the forward / reverse sensor 77, a back lamp (not shown) provided behind the traveling machine body 3 is lit to alert the surroundings. In addition, in order to prevent the traveling machine body 3 from being reversely operated in a state where the working machine is lowered (the working machine is in a working posture), the above-described working machine is set in accordance with the reverse switching detection of the traveling machine body 3. Drive up to the position.

  Further, this tractor detects the forward / reverse switching operation of the traveling machine body 3 by the forward / reverse sensor 77, so that the main clutch 22 is operated when the forward / reverse switching of the work implement is performed, so that the forward / reverse switching is smoothly performed. It is configured.

  The detection device 79 also includes inspection means. The inspection means corresponds to the inspection mark 89c provided on the mounting surface of the cylindrical portion 89 on the inner surface of the cover body 88, and the rotation trajectory of the inspection mark 89c drawn as the cylindrical portion 89 rotates. The visual recognition groove 88c formed in the upper surface of the cover body 88 and an arrow 88d drawn on the upper surface of the cover body indicating the center position in the longitudinal direction of the visual recognition groove 88c are configured. The rotational position of the cylindrical portion 89 can be known from the position of the inspection mark 89c that can be visually recognized through the.

  FIG. 13A is a plan view of the detection device when the shift rod is moved to the reverse switching position, and FIG. 13B is a plan view of the detection device when the shift rod is moved to the neutral position. C) is a plan view of the detection device when the shift rod is moved to the forward switching position. When the traveling machine body 3 is set to the neutral state by the forward / reverse switching lever 11, as shown in FIG. 13B, the inspection mark 89c is located at the position indicated by the arrow 88d. On the other hand, when the forward / reverse switching operation of the traveling machine body 3 is performed by the forward / reverse switching lever 11, the inspection mark 89c is positioned at a predetermined position other than the position indicated by the arrow 88d as shown in FIGS.

  According to the inspection means configured as described above, when the forward / reverse switching of the traveling machine body 3 is not correctly detected, whether the forward / backward switching is accurately detected due to the detection arm 91 (and the cylindrical portion 89) not operating correctly, It is possible to easily determine whether forward / reverse switching is not accurately detected due to a failure or the like of the other forward / reverse switching detection switches 92 and 93 itself.

  The example of the detection device 79 provided with the two forward / reverse switching detection switches 92 and 93 has been described above. FIG. 14 shows the detection device 79 provided with the neutral switch 94 together with the two forward / reverse switching detection switches 92 and 93. An example is shown. In addition to the detection arm 91 described above, a detection pin 96 is formed on the side periphery of the cylindrical portion 89 so as to protrude outward. The detection arm 91 and the detection pin 96 are adjacent to each other, and the tip of the detection arm 91 protrudes with respect to the cylindrical portion 89 from the tip of the detection pin 96.

  When the traveling rod 3 is moved to the neutral position by the forward / reverse operation lever 11 to bring the traveling vehicle body 3 into the neutral state, the neutral switch 94 is turned on by the detection pin 96 and turned on as shown in FIG. In addition, the two forward / reverse switching detection switches 92 and 93 are turned off by the detection arm 91 to be turned off.

  When the forward / reverse switching operation of the traveling machine body 3 is performed by the forward / reverse operation lever 11, as shown in FIGS. 14A and 14C, one of the two forward / reverse switching detection switches 92 and 93 is detected by the detection arm 91. The switch is turned on and turned on, the other is turned off and turned off, and the neutral switch 94 is turned off by the detection pin 96 and turned off. As shown in FIG. 15, the neutral switch 94 is connected to the input side of the control device 70, and an on / off signal is input to the control device 70.

  The combiner can detect the neutral state of the traveling machine body by the detection device 79, and the detection information can be used for various controls.

1 is an overall side view of a tractor to which a work vehicle of the present invention is applied. It is a side view of the driver's seat in a cabin. It is a top view of the driver's seat in a cabin. It is a power transmission system diagram of this tractor. It is a hydraulic circuit diagram of a hydraulic control apparatus. It is a block diagram of a control apparatus. It is a side view inside a tractor in the state where the detection apparatus was removed. It is a top view inside a tractor in the state where a detection device was removed. It is a perspective view of the lower surface side of a detection apparatus. It is a side view inside a tractor in the state where a detecting device was attached. It is a top view inside a tractor in the state where a detecting device was attached. (A) is a bottom view of the detection device when the shift rod is moved to the reverse switching position, (B) is a bottom view of the detection device when the shift rod is moved to the neutral position, (C) FIG. 6 is a bottom view of the detection device when the shift rod is moved to the forward switching position. (A) is a plan view of the detection device when the shift rod is moved to the reverse switching position, (B) is a plan view of the detection device when the shift rod is moved to the neutral position, (C) FIG. 5 is a plan view of the detection device when the shift rod is moved to a forward switching position. It is drawing of the detection apparatus which shows another Example, (A) is a bottom view of the detection apparatus at the time of moving a shift rod to a reverse switching position, (B) has moved the shift rod to the neutral position. (C) is a bottom view of the detection device when the shift rod is moved to the forward switching position. It is a block diagram of the control apparatus which shows another Example.

Explanation of symbols

3 Traveling body 11 Forward / reverse switching lever (forward / reverse switching operation tool)
14 Transmission 23a, 23b Input gear (gear)
41a, 41b Output gear (gear)
42 Intermediate gear
79 detector 82 shift arm 84 linkage mechanism 86 shift arm shaft 91 detection arm 92 forward switching detection switch (forward / reverse switching detection switch)
93 Reverse switch detection switch (Forward / backward switch detection switch)
94 Neutral switch

Claims (3)

  A transmission (14) for changing the gear (23a), (23b), (41a), (41b), (42) meshed by reciprocating operation of the shift rod and switching the traveling machine body (3) forward and backward, A shift arm (82) for reciprocating a shift rod, a forward / reverse switching operation tool (11) connected to the shift arm (82) via a linkage mechanism (84), and a forward / reverse switching of the transmission (14) In a work vehicle equipped with a detection device (79) for detecting the shift arm (82), the shift arm (82) is provided outside the transmission (14), and the detection device (79) is provided on the shift arm shaft (86) of the shift arm (82). A work vehicle in which the detection device (79) detects at least two rotation positions of a forward switching position and a reverse switching position of the shift arm shaft (86).   The detection device (79) includes a detection arm (91) that rotates with the shift arm shaft (86), and forward / reverse switching detection switches (92) and (93) that are turned on and off by the detection arm (91). The work vehicle according to claim 1.   The work vehicle according to claim 2, wherein the detection device (79) is provided with a neutral switch (94) for detecting a neutral position of the shift rod, and the detection switch (94) is turned on and off as the shift arm shaft (86) rotates. .

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