JP2008143323A - Travel vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To select a proper turning characteristic corresponding to the state when operating a steering wheel, in a travel vehicle constituted so as to drive a hydraulic driving device for turning in the speed increase direction and to drive a hydraulic driving device for straightly advancing in the speed reduction direction, in response to the steering wheel rotational operation quantity. <P>SOLUTION: This travel vehicle has a main shift shaft 99 transmitting only operation force from a main shift lever 73, a shift output shaft 119 transmitting operation force from the main shift lever 73 and the steering wheel 19, and a straight advance transmission shaft 126 interlocked with and connected to a straight advance control shaft 135 of a straightly advancing HST type continuously variable transmission mechanism 25 via a link mechanism 151 for straightly advancing. A connection switching means for selectively interlocking and connecting the respective shift shafts 99 and 119 with and to the straight advance transmission shaft 126 is arranged between the main shift shaft 99, the shift output shaft 119, and the straight advance transmission shaft 126. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  Conventionally, a combine as a traveling vehicle is configured to transmit power from an engine mounted on the airframe to the left and right traveling crawlers via a straight traveling hydraulic drive device, a turning hydraulic drive device, and a differential mechanism. Has been.

  An example of a combine having such a configuration is disclosed in Patent Document 1. In the combine of Patent Document 1, the drive output amount of the hydraulic drive device for straight travel, that is, the straight travel speed of the airframe is adjusted according to the operation amount of the main transmission lever provided in the control section of the airframe. If the main transmission lever is in the neutral position, the traveling aircraft does not go straight.

  On the other hand, the drive output amount of the turning hydraulic drive device, that is, the advancing (turning) direction and turning speed of the fuselage are determined by the turning direction and turning operation amount of the steering handle erected in front of the driver seat in the control unit. It is common to adjust according to.

  By the way, if the turning operation amount of the steering handle is increased in a state where the straight traveling speed initially set by the operation of the main shift lever of the operator is kept substantially constant, the traveling crawler on the outer side of the turn is proportional to the operation amount. The speed is greater than the default straight speed. For this reason, if the difference between the speed of the traveling crawler on the outer side of the turning and the speed of the traveling crawler on the inner side of the turning becomes larger as the amount of turning operation of the steering handle becomes larger, for example, Thus, if the turning radius is reduced and the aircraft is turned, there is a problem that the centrifugal force acting on the operator seated on the driver's seat becomes too large.

In this regard, in the combine disclosed in Patent Document 1, when the steering handle is operated, the turning hydraulic drive device is driven in the speed increasing direction according to the turning operation amount, and the straight drive hydraulic drive device is decelerated. Even when turning the aircraft with a small turning radius such as a spin turn, the turning speed of the aircraft can be reduced only by turning the steering handle. An increase in the acting centrifugal force was suppressed.
Japanese Patent Laid-Open No. 9-39828

  However, in the configuration of Patent Document 1, due to the turning characteristic that the turning speed of the aircraft is reduced only by turning the steering handle, the turning on the road or in the dry paddy can be made agile, the wet field or the mud surface. When it is desired to improve the turning performance, etc., there has been a problem that the agile turning feeling cannot be obtained due to the reduction of the turning speed, and the work efficiency is lowered.

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

  In order to solve this technical problem, the invention of claim 1 applies power from the engine mounted on the airframe to the left and right traveling parts via a straight drive hydraulic drive device, a turning hydraulic drive device and a differential mechanism. A linearly-moving operation body for changing the straight-ahead speed of the airframe by adjusting an output of the straight-ahead hydraulic drive device, and a turning operation body for changing the advancing direction of the airframe When the turning operation body is operated, the turning hydraulic drive device is driven in the speed increasing direction and the straight traveling hydraulic drive device is driven in the deceleration direction according to the operation amount. A first transmission shaft that transmits only the operation force from the linear operation body, a second transmission shaft that transmits the operation force from both operation bodies, and The straight oil through the link mechanism And a linear transmission shaft that is linked to the adjusting portion of the drive device, and the transmission shafts are selectively linked to the linear transmission shaft between the two transmission shafts and the linear transmission shaft. The connection switching means for this is arranged.

  According to a second aspect of the present invention, in the traveling vehicle according to the first aspect, the connection switching means includes one of a link member attached to each of the transmission shafts and an arm member fixed to the linear transmission shaft. A link pin body for detachably connecting the link member and the arm member to each other, and in a state where the link member and the arm member are connected by the link pin body, The linear transmission shaft is rotated about its own axis in conjunction with the rotation of the transmission shaft about its own axis, so that the adjustment unit of the linear drive means is operated via the linear link mechanism. It is configured.

  In the present invention, the first speed change shaft to which only the operation force from the straight operation body is transmitted, the second speed change shaft to which the operation force from the straight operation body and the turning operation body is transmitted, and the straight link mechanism. And a linear transmission shaft that is linked to the adjustment portion of the linear hydraulic drive device, and the transmission shaft is selectively connected to the linear transmission shaft between the two transmission shafts and the linear transmission shaft. Connection switching means for interlocking connection is arranged.

  When such a configuration is adopted, for example, in order to prevent the speed difference between the left and right traveling parts from becoming excessively large when the aircraft is turning, the second and second operating force transmitted from the two operating bodies is transmitted by the connection switching means. The speed change shaft and the straight transmission shaft may be linked and connected.

  Then, when the turning operation body is turned in a state where the forward operation body is operated forward (reverse), the aircraft turns to the left or right with a smaller turning radius as the turning operation amount increases. In addition, the smaller the turning radius, the lower the vehicle speed (turning speed when moving forward and backward). That is, an insensitive turning feeling can be obtained.

  Further, for example, if it is desired to make turning on the road or dry paddy agile, or to improve turning performance on a wet paddy or a mud surface, only the operation force from the straight operation body is obtained by the connection switching means. The first transmission shaft to be transmitted and the straight transmission shaft may be linked and connected.

  Then, the turning operation of the turning operation body is not related to the output adjustment of the straight drive hydraulic drive device, and the vehicle speed (turning speed) proportional to the operation amount of the rectilinear operation body is maintained as it is. A turning feeling is obtained.

  In other words, it is possible to select an appropriate turning characteristic suitable for the situation at that time and the like, and there is an effect that it is possible to contribute to improving the traveling performance of the traveling vehicle.

  In particular, according to the configuration of claim 2, a state in which the operating force from the two operating bodies is transmitted to the hydraulic drive device for linear advancement, and an operation force from the linear operation body is transmitted to the hydraulic drive device for linear advancement. In order to selectively switch the state (to switch the turning feeling of the fuselage), the link member attached to each of the transmission shafts and the arm member fixed to the linear transmission shaft are inserted and connected by a connecting pin body. Since the mechanical and simple configuration is adopted, the configuration is simpler and the number of parts is smaller than the case where electronic control using an actuator, for example, is adopted as the switching structure. It's easy to break down. In addition, the manufacturing cost can be reduced.

  Hereinafter, an embodiment embodying the present invention will be described based on the drawings (FIGS. 1 to 13) when applied to a combine as a vehicle. 1 is an overall side view of a combine, FIG. 2 is an overall plan view of the combine, FIG. 3 is a skeleton diagram of a power transmission system, and FIG. 4 is a perspective view showing a connection relationship between a main transmission lever, a steering handle, and a hydraulic drive device. FIG. 5 is an explanatory diagram schematically showing the connection relationship, FIG. 6 is a side sectional view of the steering column, FIG. 7 is an enlarged side sectional view of the upper portion of the steering column, and FIG. 8 is an enlarged side sectional view of the lower portion of the steering column. 9 is a front cross-sectional view of the steering column, FIG. 10 is an enlarged front cross-sectional view of the upper portion of the steering column, FIG. 11 is an enlarged cross-sectional view of the main part showing the operation relationship between the slide shaft and the operating lever, and FIG. FIG. 13 is a front sectional view, and FIG. 13 is an explanatory plan view showing the connection relationship between the steering handle and the hydraulic drive device.

  As shown in FIGS. 1 and 2, reference numeral 1 is a track frame for mounting a pair of left and right traveling crawlers 2 as a traveling unit, reference numeral 3 is a machine base installed on the track frame 1, and reference numeral 4 is a feed chain 5. A threshing unit that is stretched on the left side and incorporates a handling cylinder 6 and a processing cylinder 7, and a reference numeral 8 is a reaping unit that includes a cutting blade 9, a culm conveying mechanism 10, and the like. Reference numeral 11 denotes a hydraulic cylinder that raises and lowers the cutting part 8 via the cutting frame 12, reference numeral 13 denotes a rejection processing part that faces the end of the rejection chain 14, and reference numeral 15 denotes a grain that is fed from the threshing part 4 to the milling cylinder 16. It is a grain tank that is carried through. Reference numeral 17 denotes a discharge auger that carries the grains of the tank 15 out of the machine, reference numeral 18 denotes a driver's cab as a control unit including a round steering handle 19 and a driver's seat 20 as a turning operation body, and reference numeral 21 denotes An engine provided below the driver's seat 20. The combine of embodiment is comprised so that a grain straw may be continuously cut and threshed.

  As shown in FIG. 3, the transmission case 22 for driving the traveling crawler 2 includes a straight traveling HST continuously variable transmission mechanism 25 (straight traveling hydraulic drive device) including a first hydraulic pump 23 and a first hydraulic motor 24, and a second A turning HST continuously variable transmission mechanism 28 (turning hydraulic drive device) including a hydraulic pump 26 and a second hydraulic motor 27 is provided. In these HST type continuously variable transmission mechanisms 25 and 28, the input shafts 29a and 29b of the first and second hydraulic pumps 23 and 26 are connected to the output shaft 21a of the engine 21 by transmission belts 30a and 30b. 23 and 26 are driven.

  The drive shafts 34 of the left and right traveling crawlers 2 are linked and connected to the output shaft 31 of the first hydraulic motor 24 via the auxiliary transmission mechanism 32 and the differential mechanism 33. The differential mechanism 33 has a pair of planetary gear mechanisms 35 and 35 arranged symmetrically. Each planetary gear mechanism 35 is formed by one sun gear 36, three planetary gears 37 that mesh with the outer periphery of the sun gear 36, and a ring gear 38 that meshes with these planetary gears 37.

  The planetary gear 37 is rotatably supported by a carrier 41 of a carrier shaft 40 positioned on the same axis as the sun gear shaft 39, and the left and right carriers 41 are disposed opposite to each other with the left and right sun gears 36, 36 therebetween. The ring gear 38 has internal teeth 38 a that mesh with the planetary gears 37, and is rotatably supported by the carrier shaft 40. The carrier shaft 40 extends outward in the left-right direction to form an axle, and a drive wheel 34 is attached to the tip portion thereof.

  The rectilinear HST type continuously variable transmission mechanism 25 controls forward / reverse rotation and the rotational speed of the first hydraulic motor 24 by adjusting and changing the angle of the rotary swash plate of the first hydraulic pump 23. In this case, the rotational output of the first hydraulic motor 24 is transmitted from the transmission gear 42 of the output shaft 31 to the center gear 46 fixed to the sun gear shaft 39 via the gears 43, 44, 45 and the auxiliary transmission mechanism 32. As a result, the sun gear 36 is configured to rotate.

  The sub-transmission mechanism 32 includes a sub-transmission shaft 47 having a gear 44 and a parking brake shaft 49 having a gear 48 (for high speed) that meshes with the center gear 46 via the gear 45. A pair of low speed gears 50 and 51, medium speed gears 52 and 53, and high speed gears 54 and 48 are provided between the sub-transmission shaft 47 and the brake shaft 49. The sub-shift is configured to be switched between low speed, medium speed, and high speed by a slide operation of the slider 56.

  Note that there is neutrality between the low and medium speeds of the sub-shift and between the medium and high speeds. A parking brake 57 is provided on the parking brake shaft 49. Further, the cutting PTO shaft 58 that transmits the rotational force to the cutting unit 8 is connected to the auxiliary transmission shaft 47 via the gears 59, 60 and the one-way clutch 61, and the cutting unit 8 is driven at the vehicle speed synchronization speed. .

  As described above, the driving force of the first hydraulic motor 24 transmitted from the center gear 46 to the sun gear shaft 39 is transmitted to the left and right carrier shafts 40 via the left and right planetary gear mechanisms 35 and is also transmitted to the left and right carrier shafts 40. Rotational power transmitted to the left and right drive wheels 34 is configured to drive the left and right traveling crawlers 2.

  The turning HST type continuously variable transmission mechanism 28 performs forward / reverse rotation and rotation speed control of the second hydraulic motor 27 by adjusting and changing the angle of the rotary swash plate of the second hydraulic pump 26. In this case, in the transmission case 22, the brake shaft 63 having the steering output brake 62, the clutch shaft 65 having the steering output clutch 64, and the left and right input gears that are always meshed with the external teeth 38 b of the left and right ring gears 38. 66, 67.

  The clutch shaft 65 is connected to the output shaft 68 of the second hydraulic motor 27 via the brake shaft 63 and the steering output clutch 64, and the right input gear 67 is connected to the clutch shaft 65 via the normal rotation gear 69. . A left input gear 66 is connected to the clutch shaft 65 via a forward rotation gear 69 and a reverse rotation gear 70.

  By turning the low and medium speed and high speed sliders 55 and 56 to neutral and turning on the steering output brake 62 and turning off the steering output clutch 64, transmission of rotational power from the second hydraulic motor 27 is blocked.

  Further, by turning off the steering output brake 62 and turning on the steering output clutch 64 at the time of the sub-shift output other than the neutral, the rotational power of the second hydraulic motor 27 is transferred to the right side via the normal rotation gear 69. It is transmitted to the external teeth 38 b of the ring gear 38 and also transmitted to the external teeth 38 b of the left ring gear 38 via the forward rotation gear 69 and the reverse rotation gear 70. As a result, when the second hydraulic motor 27 rotates in the forward direction (reverse rotation), the left ring gear 38 rotates in the reverse direction (forward rotation) and the right ring gear 38 rotates in the forward direction (reverse rotation) at the same number of rotations in the opposite directions.

  Thus, when the first hydraulic motor 24 for straight running is driven in a state where the second hydraulic motor 27 for turning is stopped and the left and right ring gears 38 are fixed stationary, the rotational output from the first hydraulic motor 24 is the center gear. 46 is transmitted to the left and right sun gears 36 at the same rotational speed, and the left and right traveling crawlers 2 are driven at the same rotational speed in the same direction in the left and right through the planetary gear 37 and the carrier 41 of the left and right planetary gear mechanism 35. The vehicle travels straight forward and backward.

  On the other hand, when the second hydraulic motor 27 for rotation is driven to rotate in the forward and reverse directions while the first hydraulic motor 24 for rectilinear motion is stopped and the left and right sun gears 36 are stationary and fixed, the left planetary gear mechanism 35 is moved forward or backward. The planetary gear mechanism 35 on the right side rotates in the reverse direction or in the reverse direction, and the left and right traveling crawler 2 is driven in the reverse direction to turn the aircraft to the left or right.

  Further, by driving the second hydraulic motor 27 for turning while driving the first hydraulic motor 24 for straight traveling, the aircraft turns left and right to correct the course. The turning radius of the airframe is determined by the output rotational speed of the second hydraulic motor 27.

  Next, the structure around the cab 18 will be described with reference to FIGS. 2, 6, 7 and 9 to 11.

  As shown in FIGS. 2, 6 and 9, a steering column 71 is erected and fixed on the upper surface of the front portion of the cab 18. A steering handle 19 is disposed above the steering column 71 so as to be horizontally rotatable. A side column 72 is provided on the left side of the cab 18, and the mission case 22 is disposed below the side column 72. In the side column 72, a main transmission lever 73, a sub transmission lever 74, a mowing clutch lever 75, and a threshing clutch lever 76 are arranged as a straight operation body. Further, the steering column 71 is formed by molding an aluminum alloy casting, and has a split structure that can be divided into left and right. The steering column 71 having a split structure is fastened with a plurality of bolts 77 (see FIGS. 6 and 7) to form a box shape.

  As shown in FIGS. 6, 7, 9, and 10, the steering column 71 is rotatably supported by a tilt base 78 as a support member integrally formed on the steering column 71 and the tilt base 78. A lower handle shaft 86, an upper handle shaft 84 connected to the upper end of the lower handle shaft 86 via a universal joint 85 so as to protrude upward from an upper surface cover 83 covering the upper surface of the steering column 71, and the upper handle The steering handle 19 is attached to the upper end of the shaft 84.

  The tilt base 78 and the lower handle shaft 86 are located inside an upper surface cover 83 that covers the upper surface of the steering column 71. The tilt table 78 has a pair of left and right support arm portions 198 protruding upward. The upper end portion of the lower handle shaft 86 protrudes upward between the left and right support arm portions 198 of the tilt base 78.

  On the tilt base 78, an upper end portion of a steering input shaft 87 extending in the vertical direction at substantially the center inside the steering column 71 is also rotatably supported. By meshing the gear 88 of the lower handle shaft 86 and the sector gear 89 of the steering input shaft 87, the lower handle shaft 86 and the steering input shaft 87 are connected so that power can be transmitted.

  The upper handle shaft 84 is pivotally supported in the shaft case 82 protruding upward from the upper surface cover 83 so as to be rotatable about its axis. The periphery of the shaft case 82 is covered with a bellows-like boot body 81 made of soft rubber having flexibility and stretchability.

  A tilt bracket 80 as a bracket member having left and right side plates 199 is attached to the lower portion of the shaft case 82. The tilt bracket 80 is disposed so as to straddle both support arm portions 198 of the tilt base 78 from above (see FIGS. 9 and 10). The left and right side plates 199 of the tilt bracket 80 and the support arm portions 198 corresponding thereto are fastened by fulcrum bolts 79 from the left and right outer sides as tilt axes.

  The shaft portions of the left and right fulcrum bolts 79 are located on the same lateral axis X. Further, the horizontal shaft 85a (see FIGS. 6 and 7) of the universal joint 85 that connects the upper and lower handle shafts 84 and 86 is also located on the horizontal axis X. Therefore, the tilt bracket 80 and the upper handle shaft 84 and the steering handle 19 can be bent and rotated (tilt rotation) about the horizontal axis X common to the left and right fulcrum bolts 79 and the horizontal shaft 85a of the universal joint 85. It has become.

  The lower end portion of the upper handle shaft 84 protrudes downward between the left and right side plates 199 of the tilt bracket 80, and the universal joint 85 that connects the upper and lower handle shafts 84 and 86 includes the left and right side plates 199 and the left and right support arms. It is located in the area surrounded by the part 198.

  The left and right side plates 199 of the tilt bracket 80 and the left and right support arms 198 of the tilt base 78 adjust the tilt angle of the tilt bracket 80 and the upper handle shaft 84 and the steering handle 19 in a stepless manner. -It is associated through the posture adjustment means 200 for holding.

  The posture adjusting means 200 includes a tilt bracket 80 and a tilt base 78, a lateral slide shaft 201 that penetrates the left and right side plates 199 of the tilt bracket 80 and the left and right support arm portions 198 of the tilt base 78, and an operation lever 204. A clamping means 202 is provided that can selectively switch the upper handle shaft 84 and the steering handle 19 between a locked state and a free state by an operation (described in detail later).

  The slide shaft 201 extends in parallel with the lateral axis X, which is the pivot axis of the tilt bracket 80, and is configured to be slidable left and right along the axial direction. The left and right side plates 199 of the tilt bracket 80 are formed with substantially arc-shaped guide slots 203 having a fulcrum bolt 79 (lateral axis X) as the center of curvature. The end of the slide shaft 201 is inserted into the guide slot 203.

  The upper handle shaft 84 and the steering handle 19 are bent and rotated around the fulcrum bolt 79 by moving each end of the slide shaft 201 relatively along the guide slot 203 of the left and right side plates 199. It is allowed within a range of 203 arc lengths. That is, the tilt rotation strokes of the upper handle shaft 84 and the steering handle 19 are regulated by the end portions of the slide shaft 201 coming into contact with both ends of the guide slot 203 in the longitudinal direction.

  If the guide groove 203 is provided in either the left and right side plates 199 of the tilt bracket 80 or the left and right support arm portions 198 of the tilt base 78, the tilt bracket 80 and thus the upper handle shaft 84 and the steering handle 19 are provided. Needless to say, bending rotation (tilt rotation) around the lateral axis X is possible.

  One end of the slide shaft 201 that protrudes outward from one side plate 199 of the tilt bracket 80 is a direction in which the base end (upper end) of the substantially rod-shaped operation lever 204 intersects the axis of the slide shaft 201 (implementation). It is attached via a pivot pin 205 extending in the front-rear direction. The operation lever 204 is configured to be rotatable up and down around the axis of the pivot pin 205.

  The clamping means 202 includes a pressing head 206 formed at the other end of the slide shaft 201 (a portion protruding outward from the other side plate 199 of the tilt bracket 80) and a vertical rotation around the pivot pin 205 of the operation lever 204. It is configured by a switching cam 207 formed in the middle part of the operation lever 204 so that the slide shaft 201 is slid left and right by a moving operation (see FIGS. 9 to 11).

  A pressing head 206 formed at the other end of the slide shaft 201 is formed to have a larger diameter than the diameter of the slide shaft 201. A surface of the pressing head 206 that faces the other side plate 199 of the tilt bracket 80 is a contact surface that can be in close contact with the other side plate 199.

  A pair of front and rear bracket pieces 208 project outward from a portion of the one side plate 199 of the tilt bracket 80 below the slide shaft 201. The switching cam 207 of the operation lever 204 is sandwiched and positioned between the front and rear bracket pieces 208. Both the front and rear bracket pieces 208 and the switching cam 207 are connected to each other by long linkage pins 209.

  A loose fitting hole 210 is formed in each bracket piece 208. The end portions of the linkage pins 209 are inserted into the loose fitting holes 210 so as to be movable. Accordingly, the vertical rotation of the operation lever 204 around the pivot pin 205, and hence the sliding movement of the slide shaft 201, is within the range in which each end of the linkage pin 209 can be displaced, that is, the hole diameter of the loose fitting hole 210. Allowed within range.

  On the opposite side of the switching cam 207 to the one side plate 199 of the tilt bracket 80, upper and lower two-level convex portions 211a and 211b are formed. When the operation lever 204 is turned up and down around the pivot pin 205, the upper convex portion 211a of the switching cam 207 is perpendicular to the one side plate 199 of the tilt bracket 80 and passes through the axis of the linkage pin 209 (see FIG. 11), the switching cam 207 is in a so-called fulcrum state.

  The operation lever 204 extends substantially parallel to the one side plate 199 of the tilt bracket 80 and closes to the one side plate 199 by the action of the upper convex portion 211a exceeding the fulcrum (see the solid line state in FIGS. 10 and 11). And a free operation state extending obliquely downward and away from the one side plate 199 (see the two-dot chain line state in FIGS. 10 and 11). The lower convex portion 211b is set so as to press and contact the one side plate 199 of the tilt bracket 80 together with the upper convex portion 211a when the operation lever 204 is in the locking operation posture. In order to achieve the fulcrum crossing action, not only the convex portion 211 of the switching cam 207 but also spring means such as a coil spring can be used.

  When the operation lever 204 is turned downward around the pivot pin 205 to the lock operation posture (see the solid line state in FIGS. 10 and 11), the slide shaft 201 is moved to the base end portion of the operation lever 204 in FIGS. 11, the pressing head 206 of the slide shaft 201 is pressed against the other side plate 199 of the tilt bracket 80. At this time, the upper convex portion 211a of the switching cam 207 climbs over the action line BL from the bottom to the top (over the fulcrum), and holds the operation lever 204 in the lock operation posture.

  Then, the pressing head 206 of the slide shaft 201 and the switching cam 207 (upper and lower convex portions 211a and 211b) of the operation lever 204 move the left and right side plates 199 of the tilt bracket 80 and the left and right support arm portions 198 of the tilt base 78 to the left and right sides. The tilt bracket 80 is fixed so as not to rotate. As a result, the upper handle shaft 84 and the steering handle 19 are held in a locked state where they cannot be bent and rotated.

  Conversely, when the operation lever 204 is turned upward around the pivot pin 205 to a free operation posture (see the two-dot chain line state in FIGS. 10 and 11), the slide shaft 201 is formed at the base end of the operation lever 204. Is pushed in the direction of arrow F in FIGS. 10 and 11, and the pressing head 206 of the slide shaft 201 moves away from the other side plate 199 of the tilt bracket 80. At this time, the upper convex portion 211a of the switching cam 207 climbs over the action line BL from above (beyons the fulcrum) and holds the operation lever 204 in a free operation posture. The lower convex portion 211b is separated from the other side plate 199. As a result, the holding of the tilt bracket 80 and the tilt base 78 by the pressing head 206 and the switching cam 207 is released, and the tilt bracket 80 becomes rotatable around the fulcrum bolt 79. As a result, the upper handle shaft 84 and the steering handle 19 are in a free state in which they can be bent and rotated.

  In this case, a window hole 212 is formed at a position facing the operation lever 204 in one side portion of the upper surface cover 83. The window hole 212 is closed by an openable / detachable lid cover body 213. When the operation lever 204 is in a free operation posture, if the tip of the operation lever 204 is set to protrude from the window hole 212, the lid cover body 213 cannot be closed, and the window hole 212 is opened halfway. For this reason, an effect can be exhibited in preventing the lock of the upper handle shaft 84 and the steering handle 19 from being forgotten.

  According to the above configuration, the posture adjusting means 200 includes the upper handle shaft 84 and the upper handle shaft 84 by the operation of the operation lever 204 that can be rotated up and down around the axis of the pivot pin 205 extending in the direction intersecting the lateral axis X. Since the steering handle 202 is provided that can selectively switch the steering handle 19 between the locked state and the free state, the operator can see the operation lever 204 in its posture (whether it is close to or far from the posture adjusting unit 200). Therefore, it is possible to intuitively and reliably grasp whether the upper handle shaft 84 and the steering handle 19 are in the locked state or the free state.

  For this reason, it is possible to significantly reduce the possibility that the operator mistakes the operation of locking the upper handle shaft 84 and the steering handle 19 and the operation of making it free, and the user friendliness is also excellent from the viewpoint of universal design. Become.

  Further, in the embodiment, the pressing head 206 and the switching cam 207 cause the tilt bracket 80 and the tilt base 78 to be moved by the left and right sliding movement of the slide shaft 201 accompanying the up and down rotation operation around the pivot pin 205 of the operation lever 204. Since it is configured so as to be clamped and released from both the left and right sides, the pressing head for the tilt bracket 80 and the tilt base 78 as compared with the conventional nut tightening type (see Patent Document 1, etc.). Variations in the clamping force (lock holding force) between the portion 206 and the switching cam 207 can be suppressed, and the lock holding force can be maintained and stabilized in a high state.

  Next, a connection structure between the main transmission lever 73 and the steering handle 19 and the hydraulic drive devices 25 and 28 will be described with reference to FIGS.

  The steering input shaft 87 and the main speed change lever 73 connected to the lower handle shaft 86 of the steering handle 19 so as to be able to transmit power are linked to mechanical switching means 101 arranged in the steering column 71.

The mechanical switching means 101 is
1. When the steering handle 19 is rotated to a position other than the neutral position while the main transmission lever 73 is tilted to a position other than the neutral position, the aircraft moves to the left or right with a smaller turning radius as the rotation operation amount increases. The vehicle speed of the aircraft (turning speed when moving forward and backward) decreases as the turning radius decreases.
2. Even when the main transmission lever 73 is tilted in either the forward or backward direction, the turning operation direction of the steering handle 19 coincides with the turning direction of the machine body (if the steering handle 19 is turned to the right). The aircraft turns right, and if the steering handle 19 is turned to the left, the aircraft turns left)
3. If the main transmission lever 73 is in the neutral position, it does not function even if the steering handle 19 is operated.
In order to execute various operations, the operating force from the main transmission lever 73 and the steering handle 19 is appropriately converted to double shafts 125 and 126 (details will be described later) provided at the bottom of the steering column 71. Configured to communicate.

  The mechanical switching means 101 of the embodiment includes a steering mechanism 118 for changing the traveling direction of the airframe, and a speed change mechanism 124 for changing the vehicle speed (traveling speed) of the airframe and switching between forward and backward travel. Yes.

  First, the specific structure of the mechanical switching means 101 will be described.

  As shown in FIGS. 9 and 12, a bearing member 90 is detachably fixed on the left side surface of the steering column 71 at approximately the middle of the vertical width. The bearing member 90 cantilever-supports one end portion of the speed change input shaft 91 via a bearing 92, and the speed change input shaft 91 is supported by the bearing member 90 in a substantially horizontal posture in the left-right direction. Yes.

  As shown in FIGS. 4 to 9 and 12, the lower end of the steering input shaft 87 is connected to the upper end side of the input fulcrum shaft 94 via a universal joint 93. A steering input member 95 is fixed to the input fulcrum shaft 94. The steering input member 95 is rotatably connected to the transmission input shaft 91 through a bearing 95a. The universal joint 93 is located at an intersection where the axis of the substantially vertical steering input shaft 87 and the axis of the substantially horizontal shift input shaft 91 are orthogonal to each other.

  That is, the steering input member 95 rotates forward and backward around the same and substantially vertical axis as the steering input shaft 87 when the steering input shaft 87 rotates forward and backward. By reverse rotation, it is configured to tilt in the front-rear direction together with the input fulcrum shaft 94 about the same horizontal axis as the speed change input shaft 91.

  An input coupling body 96 is detachably fixed to the steering input member 95 with a linkage bolt 97. For this reason, when the steering input shaft 87 is rotated in the forward and reverse directions around the axis by the turning operation of the steering handle 19, the steering input member 95 and the input coupling body 96 are moved forward and backward around the steering input shaft 87. Reverse rotation.

  As shown in FIGS. 4 to 6, 8, 9 and 12, a horizontally long main transmission shaft 99 as a first transmission shaft is rotatably supported on the lower front side of the steering column 71. The left end of the main transmission shaft 99 protrudes outward from the left side of the steering column 71, and this protruding end is connected to the main transmission lever 73 on the side column 72 via the main transmission link 100. The main speed change lever 73 is used to move the vehicle body 1 forward, stop, reverse and change the vehicle speed steplessly. When the main speed change lever 73 is tilted in the front-rear direction, the operating force is changed to the main speed change link 100. Is transmitted to the main transmission shaft 99, and the main transmission shaft 99 is rotated forward and backward about its axis.

  The main transmission shaft 99 is also linked to the transmission input shaft 91 via the rod-type main transmission member 110 and the lower link 112. Therefore, when the main transmission shaft 99 is rotated forward and backward about its axis by the forward and backward tilting operation of the main transmission lever 73, the transmission input shaft 91 is rotated forward and backward about the axis, and as a result, the steering input is performed. The member 95 tilts back and forth together with the input fulcrum shaft 94.

  A cylindrical steering output shaft 113 is rotatably fitted on the outer periphery of the main transmission shaft 99. The link type steering output member 114 fixed to the steering output shaft 113 is connected to the lower end portion of the rod type steering coupling member 115 via a ball joint type steering output connecting portion 117. An upper end portion of the rod-type steering coupling member 115 is connected to the input connection body 96 via a universal joint-type steering input connection portion 116.

  In the embodiment, the combination of the steering output shaft 113, the link type steering output member 114, the rod type steering coupling member 115, the universal joint type steering input connecting portion 116, and the ball joint type steering output connecting portion 117 is The steering mechanism 118 for changing the traveling path of the aircraft is configured.

  A shift output shaft 119 serving as a second shift shaft extending in parallel with the main output shaft 99 and the steering output shaft 113 is rotatably supported at a position above the steering output shaft 113 in the steering column 71. Yes. The link type transmission output member 120 fixed to the transmission output shaft 119 is connected to the lower end portion of the transmission coupling member 121 via a ball joint type transmission output connection part 123. The upper end portion of the rod-type speed change coupling member 121 is connected to the input connection body 96 via a universal joint type speed change input connection portion 122.

  In the embodiment, the combination of the speed change output shaft 119, the link type speed change output member 120, the rod type speed change coupling member 121, the universal joint type speed change input connection portion 122, and the ball joint type speed change output connection portion 123 is determined by the vehicle speed ( A speed change mechanism 124 for changing the travel speed) and switching between forward and backward travel is configured.

  Next, a connection structure from the double shafts 125 and 126 to the hydraulic drive devices 25 and 28 will be described.

  As shown in FIGS. 6, 8, 9, and 12, the bearing portion 127 provided at the bottom of the steering column 71 and near the center of the left and right widths has an outer turning transmission cylinder shaft 125 and an inner rectilinear advance. A double shaft composed of a transmission shaft 126 is vertically concentric and is rotatably supported independently of each other.

  The upper ends of the double shafts 125 and 126 protrude into the steering column 71, while the lower ends of the double shafts 125 and 126 protrude to the lower surface side of the cab 18.

  The upper end portion of the turning transmission cylinder shaft 125 is connected via a turning upper link member 133 protruding from the turning transmission cylinder shaft 125, a steering output link 132 protruding from the steering output shaft 113, and a ball joint shaft 131 connecting them. Thus, the steering output shaft 113 is interlocked. A lower end portion of the turning transmission cylinder shaft 125 is linked to a turning control shaft 140 protruding from the turning HST type continuously variable transmission mechanism 28 via a turning link mechanism 150.

  The turning control shaft 140 is for adjusting the inclination angle (swash plate angle) of the rotary swash plate of the second hydraulic pump 26 in the turning HST type transmission mechanism 28, and the shift output of the turning HST type transmission mechanism 28. Functions as an adjustment unit that adjusts That is, by adjusting the swash plate angle of the second hydraulic pump 26 by forward / reverse rotation of the turning control shaft 140, the rotational speed control and forward / reverse switching of the second hydraulic motor 27 are executed, and the steering angle ( Stepless change of the turning radius) and switching of the left and right turning directions are performed.

  The turning link mechanism 150 of the embodiment includes a turning lower link member 139 protruding from the turning transmission cylinder shaft 125, a steering control arm 141 fixed to the turning control shaft 140, and a turning rod 138 with a turnbuckle 137 connecting them. It has.

  On the other hand, the upper and lower ends of the straight transmission shaft 126 protrude further upward and downward from the turning transmission cylinder shaft 125. A pair of upper and lower direct links 160 and a normal link 130 formed in a substantially L shape in plan view are fitted to the upper end of the linear transmission shaft 126 so as to be rotatable. A horizontally long arm member 159 is fixed between the upper and lower links 160 and 130 of the linear transmission shaft 126.

  The first arm portion 130 a of the normal link 130 is connected to a speed change output link 129 protruding from the speed change output shaft 119 via a ball joint shaft 128. Further, the first arm portion 160 a of the direct connection link 160 is connected to a direct connection transmission link 156 that rotates integrally with the main transmission shaft 99 via a ball joint shaft 155.

  Each of the links 160 and 130 and the arm member 159 are configured so as to be selectively interlocked by a substantially U-shaped connecting pin body 161 that constitutes a connection switching means. That is, as shown in FIGS. 9, 12, and 13, the lengths of the second arm portions 160 b and 130 b and the arm member 159 of the upper and lower links 160 and 130 are exposed at the front end (rear end) side in plan view. As shown, the arrangement position becomes longer as it goes from the top to the bottom. Fitting holes 160c, 130c, and 159c penetrating vertically are formed in the second arm portions 160b and 130b of the upper and lower links 160 and 130 and the distal ends of the arm members 159, respectively.

  By inserting each leg portion of the connecting pin body 161 into the fitting hole 130c of the normal link 130 and the fitting hole 159c of the arm member 159 from above (refer to the solid line state in FIGS. 6, 8 and 13), the normal The link 130 is rotatable integrally with the arm member 159 (straight-forward transmission shaft 126). Further, by inserting each leg portion of the connecting pin body 161 into the fitting hole 160c of the direct connection link 160 and the fitting hole 159c of the arm member 159 from above (the two-dot chain line state in FIGS. 6, 8, and 13) The direct link 160 can be rotated integrally with the arm member 159 (the straight transmission shaft 126).

  In the embodiment, a maintenance window 147 is opened at a position facing the connecting pin body 161 on the rear surface of the steering column 71. The maintenance window 147 is closed with a detachable or openable lid 148.

  The direct connection transmission link 156, the ball joint shaft 155, and the direct connection link 160 correspond to the link member on the first transmission shaft (main transmission shaft 99) side described in the claims, and the transmission output link 129, the ball joint shaft 128. The normal link 130 corresponds to a link member on the second speed change shaft (speed change output shaft 119) described in the claims. Both link members, the arm member 159, and the connection pin body 161 constitute the connection switching means described in the claims.

  The lower end portion of the straight transmission shaft 126 is interlocked and connected to the straight control shaft 135 protruding from the straight HST continuously variable transmission mechanism 25 via a straight link mechanism 151. The rectilinear control shaft 151 is for adjusting the inclination angle (swash plate angle) of the rotary swash plate of the first hydraulic pump 23 in the rectilinear HST continuously variable transmission mechanism 25. It functions as an adjustment unit that adjusts the shift output. That is, by adjusting the swash plate angle of the first hydraulic pump 23 by forward / reverse rotation of the rectilinear control shaft 135, the rotational speed control and forward / reverse switching of the first hydraulic motor 24 are executed, and the traveling speed (vehicle speed) is adjusted. Stepless change and forward / reverse switching are performed.

  The linear link mechanism 151 of the embodiment includes a linear link lower link member 144 protruding from the linear transmission shaft 126, a vehicle speed control arm 136 fixed to the linear control shaft 135, and a vehicle speed rod 143 with a turnbuckle 142 that connects these. ing.

  An accelerator lever 145 is provided on the right outer surface of the steering column 71 so as to tilt forward and backward. The accelerator lever 145 is connected to a fuel supply unit (not shown) to the engine 21 via an accelerator wire 146 that extends along the inside of the front surface of the steering column 71. By the forward / backward tilting operation of the accelerator lever 145, the fuel supply amount, and thus the rotational speed of the engine 21 is adjusted.

  Next, the behavior of the connecting structure when the main transmission lever 73 and the steering handle 19 are operated will be described with reference to FIG. First, a case where the normal link 130 and the arm member 159 are interlocked and connected by the connecting pin body 161 (hereinafter referred to as a normal case) will be described.

  When the main transmission lever 73 is in the neutral position, the steering input member 95, the input coupling body 96, the rod-type steering coupling member 115, and the rod-type transmission coupling member 121 are not affected even if the steering handle 19 is turned left and right. The link type steering output member 114, the link type transmission output member 120, the steering output shaft 113, and the transmission output shaft 119 are maintained in the stopped state because they move along the conical locus C around the axis of the steering input shaft 87. Is done.

  When a forward (reverse) operation is performed to tilt the main transmission lever 73 forward (rearward), the steering input member 95 and the input are operated by the operation force from the main transmission shaft 99 via the lower link 112 and the rod-type main transmission member 110. While the connecting body 96 is tilted forward (rearward) around the shift input shaft 91 and the universal steering input connecting portion 116 is stopped at a predetermined position, the universal joint shifting input connecting portion 122 is moved upward (downward). ) And the shift output shaft 119 is normally rotated (reversely rotated) by swinging the link-type shift output member 120 upward (downward).

  Then, the linear transmission shaft 126 rotates forward (reversely) about its axis from the transmission output shaft 119 by the operating force via the link members 128 to 130 and the arm member 159 on the transmission output shaft 119 side. In the forward rotation (reverse rotation), the straight travel link mechanism 151 is pushed and pulled, and the straight travel control shaft 135 of the first hydraulic pump 23 is rotated forward and backward. As a result, the airframe (the left and right traveling crawlers 2) performs a forward (reverse) operation in proportion to the forward / backward tilting operation amount of the main transmission lever 73.

  When the steering handle 19 is rotated leftward (rightward) with the main transmission lever 73 moving forward (reverse), the steering input member 95 moves forward (rearward) around the transmission input shaft 91. In a tilted position, the steering input shaft 87 is rotated forward (reversely) to move the universal joint type steering input connecting portion 116 upward (downward), and the link-type steering output member 114 swings upward (downward). The steering output shaft 113 is rotated forward (reversely) by the movement.

  Then, the turning transmission cylinder shaft 126 rotates forward (reversely) about its axis by the operating force from the steering output shaft 113 via the ball joint shaft 131, the steering output link 132, and the upper link member 133 for turning. In this forward rotation (reverse rotation), the turning link mechanism 150 is pushed and pulled, and the turning control shaft 140 of the second hydraulic pump 26 is rotated forward and backward. As a result, the left traveling crawler 2 is driven in the deceleration (acceleration) direction in proportion to the rotation operation amount of the steering handle 19, while the right traveling crawler 2 is driven in the acceleration (deceleration) direction to the left ( Turn the aircraft in the direction of (right) and correct its travel path.

  In this case, at the same time as the travel route correction operation, the steering input is performed in a posture in which the input connecting body 96 is tilted forward (rearward) around the transmission input shaft 91 by the left (right) turning operation of the steering handle 19. Forward rotation (reverse rotation) about the shaft 87 moves the universal joint type shift input connecting portion 122 downward (upward), and the shift output shaft 119 reverses when the link type shift output member 120 swings downward (upward). (Forward).

  For this reason, the rectilinear transmission shaft 125 is reversely rotated (forward rotation) about its axis by the return operation force from the speed change output shaft 119, and the rectilinear link mechanism 151 is proportional to the rotation operation amount of the steering handle 19. Then, the rectilinear control shaft 135 is reversely rotated (forward rotation), and the forward (reverse) speed of the airframe is decelerated corresponding to the turning radius at that time.

  That is, in the normal case, when the steering handle 19 is rotated in a state where the main shift lever 73 is operated forward (reverse), the turning is corrected in proportion to the rotational operation amount of the steering handle 19. As the radius and the deceleration amount of the traveling speed change and the turning operation amount of the steering handle 19 increases, the speed difference between the left and right traveling crawlers 2 increases, the turning radius decreases, and the traveling speed deceleration amount increases. The vehicle speed becomes slower.

  Further, the movement of the universal joint type swivel input connecting portion 116 is reversed with respect to the turning operation of the steering handle 19 at the time of forward movement and the backward movement, and the rotation operation of the steering handle 19 is performed at any time of forward and backward movement. The direction and the turning direction of the aircraft coincide.

  Next, a case where the direct connection link 160 and the arm member 159 are interlocked and connected by the connection pin body 161 (hereinafter referred to as a direct connection case) will be described. In this case, even if the forward (reverse) operation of tilting the main transmission lever 73 forward (rearward) is performed, the normal link 130 can be freely rotated with respect to the linear transmission shaft 126. , The operating force from the transmission output shaft 119 is not transmitted to the straight transmission shaft 126.

  The operating force (forward (reverse) rotational force) transmitted to the main transmission shaft 99 is directly applied to the linear transmission shaft 126 via the ball joint shaft 155, the direct transmission link 156, the direct connection link 160, and the arm member 159. The straight transmission shaft 126 is forwardly rotated (reversed) about its axis. Then, the forward link mechanism 151 is pushed and pulled by such forward rotation (reverse rotation), and the linear movement control shaft 135 of the first hydraulic pump 23 is rotated forward and backward. As a result, the machine body (the left and right traveling crawlers 2) is mainly driven. A forward (reverse) operation is executed in proportion to the forward / backward tilt operation amount of the transmission lever 73.

  When the steering handle (19) is rotated leftward (rightward) with the forward (reverse) operation by the main transmission lever 73, the steering handle 19 is rotated as in the normal case. In proportion to the amount of operation, the left traveling crawler 2 is driven in the deceleration (acceleration) direction, while the right traveling crawler 2 is driven in the acceleration (deceleration) direction, and the aircraft is turned in the left (right) direction. Correct the driving path. Simultaneously with the travel course correcting operation, the shift output shaft 119 is reversely rotated (normally rotated) in conjunction with the left (right) turning operation of the steering handle 19.

  However, as described above, in the case of the direct connection, since the operation force from the main transmission shaft 99 via the transmission output shaft 119 is not transmitted to the linear transmission shaft 126, the steering operation of the steering handle 19 and the straight traveling HST type The output adjustment of the step transmission mechanism 25 is not related. Therefore, the vehicle speed (turning speed) proportional to the amount of tilting operation of the main transmission lever 73 is maintained as it is.

  It should be noted that the operation mode when the main transmission lever 73 is in the neutral position and that the turning operation direction of the steering handle 19 coincides with the turning direction of the machine body in both forward and backward movements are the same as in the normal case. Therefore, detailed description is omitted.

  In the above configuration, for example, the normal link 130 and the arm member 159 may be inserted and connected by the connecting pin body 161 in order to prevent the speed difference between the left and right traveling crawlers from becoming excessively large when the aircraft is turning. Then, when the steering handle 19 is rotated with the main shift lever 73 moving forward (reverse), the aircraft turns to the left or right with a smaller turning radius as the amount of rotation increases. In addition, the smaller the turning radius, the lower the vehicle speed (turning speed when moving forward and backward). That is, an insensitive turning feeling can be obtained.

  In addition, if it is desired to make a quick turn on the road or in a dry paddy or to improve the turning performance on a wet paddy or mud surface, the direct connection link 160 and the arm member 159 are inserted and connected by a connection pin body 161. That's fine. Then, the turning operation of the steering handle 19 and the output adjustment of the HST type continuously variable transmission mechanism 25 for straight travel are not related, and the vehicle speed (turning speed) proportional to the forward / backward tilting operation amount of the main transmission lever 73 is maintained. Maintained and agile turning feeling is obtained.

  Therefore, it is possible to select an appropriate turning characteristic suitable for the work situation at that time, and it is possible to contribute to the improvement of the running performance of the airframe and the efficiency of the mowing and threshing work.

  Further, in the embodiment, the operating force from the main transmission lever 73 and the steering handle 19 is transmitted to the straight traveling HST continuously variable transmission mechanism 25, and only the operating force from the main transmission lever 73 is used for the straight traveling HST type. In order to selectively switch the state of transmission to the step transmission mechanism 25 (to switch the turning feeling of the airframe), the direct link 160 on the main transmission shaft 99 side or the normal link 130 on the transmission output shaft 119 side, and the arm member Since the mechanical and simple configuration of inserting and connecting 159 with the connecting pin body 161 is employed, as a structure for such switching, for example, compared to the case where electronic control using an actuator or the like is employed, The structure is simple, the number of parts is small, and it is difficult to break down. Also, the manufacturing cost is low.

  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 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.

It is a whole side view of a combine. It is a whole top view of a combine. It is a skeleton figure of a power transmission system. It is a perspective explanatory view showing the connection relationship between the main transmission lever and the steering handle and the hydraulic drive device. It is explanatory drawing which shows the said connection relationship typically. It is side surface sectional drawing of a steering column. It is an expanded side sectional view of the steering column upper part. It is an expanded side sectional view of a steering column lower part. It is front sectional drawing of a steering column. It is an enlarged front sectional view of the upper part of the steering column. It is a principal part expanded sectional view which shows the action | operation relationship between a slide shaft and an operation lever. It is an expanded front sectional view of the steering column lower part. It is a plane explanatory view showing the connection relation between the steering handle and the hydraulic drive device.

Explanation of symbols

2 Traveling crawler 18 Driver's cab 19 Steering handle 20 as a turning operation body Driver's seat 21 Engine 22 Transmission case 25 Straight running HST continuously variable transmission mechanism 28 as a straight running hydraulic drive device 28 Turning HST as a turning hydraulic drive device Type continuously variable transmission mechanism 99 Main transmission shaft 101 as first transmission shaft Mechanical switching means 113 Steering output shaft 118 Steering mechanism 119 Shifting output shaft 124 as second transmission shaft Transmission mechanism 125 Swivel transmission cylinder shaft 126 Straight transmission Shaft 128 Ball joint shaft 129 Speed change output link 130 Normal link 130a First arm portion 130b Second arm portion 130c Fitting hole 131 Ball joint shaft 132 Steering output link 133 Upper link member 135 for turning Straight control shaft 140 Turning control Shaft 150 Turning link mechanism 151 Straight running link mechanism 155 Ball joint shaft 156 Direct transmission Link 159 Arm member 159c Fitting hole 160 Direct connection link 160a First arm portion 160b Second arm portion 160c Fitting hole 161 Connecting pin body

Claims (2)

While configured to transmit the power from the engine mounted on the airframe to the left and right traveling units via a straight hydraulic drive, a turning hydraulic drive and a differential mechanism,
A rectilinear operation body for adjusting the output of the straight traveling hydraulic drive device to change the rectilinear speed of the airframe; and a swiveling operation body for changing the advancing direction of the airframe. A traveling vehicle configured to drive the turning hydraulic drive device in a speed increasing direction and to drive the rectilinear hydraulic drive device in a deceleration direction according to the operation amount when the body is operated; There,
The first transmission shaft to which only the operation force from the linear operation body is transmitted, the second transmission shaft to which the operation force from the two operation bodies is transmitted, and the linear drive hydraulic drive device via the linear link mechanism With a straight transmission shaft linked to the adjustment part of
A traveling vehicle characterized in that connection switching means for selectively interlockingly connecting each of the transmission shafts to the linear transmission shaft is disposed between the both transmission shafts and the linear transmission shaft. The connection switching means removably connects the link member attached to each transmission shaft, the arm member fixed to the linear transmission shaft, and any one of the link member and the arm member. With a connecting pin body,
In a state where the link members and the arm members are connected by the connecting pin body, the linear transmission shaft rotates about its own axis in conjunction with the rotation of each of the transmission shafts about its own axis. 2. The traveling vehicle according to claim 1, wherein the adjustment unit of the straight drive means is operated via the straight link mechanism. 3.

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