JP2007230358A - Gear shifting device of work vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gear shifting device of a work vehicle capable of enhancing operability by the interlocking of the speed change operation of a tractor having a HST and the operation of a shuttle operation type forward/backward lever, and obtaining an operational feeling by the speed change lever without any sense of incongruity. <P>SOLUTION: The gear shifting device of the work vehicle comprises a continuously variable transmission (3) for transmitting rotational power to traveling devices (1F, 1R), the continuously variable transmission (3), a speed change lever (6) for changing the output rotation speed of the continuously variable transmission (3), and an interlocking mechanism (L) capable of switching the output rotational direction of the continuously variable transmission (3) to the same operational direction of the speed change lever (6) to the forward direction and the reverse direction based on the switching operation of a forward/backward switching lever (5). The interlocking mechanism (L) sets the output number of the rotation of the continuously variable transmission (3) substantially proportional to the speed change operational amount of the speed change lever (6). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a work vehicle for agriculture, construction, and transportation, and in particular, a work vehicle having a continuously variable transmission and having a so-called shuttle operation type forward / reverse switching lever that switches forward and backward of a vehicle body and a shift lever that adjusts the vehicle speed. The present invention relates to a shift operation device.

  Conventionally, agricultural tractors have a geared forward / reverse switching mechanism and a gear-type transmission, and operate the forward / reverse switching mechanism with a so-called shuttle-operated forward / reverse switching lever provided below the steering wheel. A configuration is known in which a transmission is operated by a shift lever provided on the side. Further, the tractor is also known in which the transmission is configured by HST and the vehicle is operated to move forward and backward and shift with a single lever (shift lever).

As described above, the tractor including the gear-type transmission and operating the vehicle with the forward / reverse switching lever and the shift lever is mainly used for high load work that repeats forward / backward movement, for example, loader work, etc. The tractor is mainly used for lawn mowing work where fine vehicle speed adjustment is required.
JP2003-134903

  The tractor user is equipped with the HST according to the main work and is designed to operate the vehicle body with a single lever or with a gear-type transmission, and the vehicle body is moved with the forward / reverse switching lever and the transmission lever. Since the specifications to be operated are selected, when performing lawn mowing work other than the main work, for example, with a tractor equipped with a gear-type transmission, the vehicle speed cannot be finely adjusted and the operability is poor, and the HST is provided. In the tractor, it is necessary to adjust the shift position each time the forward / backward movement is switched in the loader work or the towing work in the field where the forward / backward movement is repeated, and the operability is impaired as described above. Further, if these transmissions are constituted by electric or hydraulic equipment such as switches and motors, a problem that production costs are high is assumed.

In view of the above-mentioned problems, the present invention is configured as follows.
That is, according to the first aspect of the present invention, the continuously variable transmission (3) that transmits the rotational power of the engine (E) to the travel device (1F, 1R), the continuously variable transmission (3), and the continuously variable transmission A continuously variable transmission (3) for the same operating direction of the shift lever (6) based on the switching operation of the shift lever (6) for shifting the output rotational speed of the device (3) and the forward / reverse switching lever (5) A shift operation device characterized in that an interlocking mechanism (L) capable of switching the output rotation direction between the forward rotation direction and the reverse rotation direction is provided.

In the invention of claim 1 configured as described above, when the forward / reverse switching lever (5) is operated, the output rotation direction of the continuously variable transmission (3) with respect to the same operation direction of the transmission lever (6) is the normal rotation direction or Switch to reverse direction.
Therefore, it is possible to reversely move with the output rotation set to a predetermined traveling direction.

  According to a second aspect of the present invention, in the first aspect, the interlock mechanism (L) is configured so that the output rotational speed of the continuously variable transmission (3) is substantially proportional to the speed change operation amount of the speed change lever (6). If comprised in this way, since the operation amount of a speed-change lever (6) and the increase / decrease amount of an output rotation speed are proportional, an operation feeling is good.

  In the invention of claim 3, the interlock mechanism (L) includes the first locking groove (55b), the first engagement pin (53p) and the second locking groove (55a) that engage with the locking groove (55b). ) And a second engagement pin (54p) that engages with the locking groove (55a), and the turntable (55) is rotatably supported about the vertical axis (X). In addition, the rotary table support cylinder (65) that supports the rotary table (55) so as to be able to reciprocate in the lateral direction, and the displacement of the second engagement pin (54p) accompanying the reciprocating movement of the rotary table (55) A trunnion shaft interlocking mechanism (54b, 54, 54a, 56, 7a) for transmitting to the trunnion shaft (7), and the rotary table support cylinder (65) reciprocally moves in conjunction with the operation of the speed change lever (6). The first engaging pin (53p) is configured to swing in conjunction with the operation of the forward / reverse switching lever (5). By rotating the turntable (55) around the vertical axis (X), the turnable range of the trunnion shaft (7) is changed from the forward range (F) to the reverse range (R), or the reverse range (R). The shift operation device for a work vehicle according to claim 1 or 2, wherein the shift operation device is configured to be switched from a forward range to a forward range (F).

  When configured as described above, the forward / reverse switching lever (5) is operated in a predetermined manner, and the turntable (55) is rotated about the vertical axis (X) via the first engagement pin (53p) to thereby turn the trunnion shaft. (7) is set to rotate in the forward range or in the reverse range. When the speed change lever (6) is operated from this state, the second engaging pin (54p) that engages the second locking groove (55a) by interlocking with the rotating table (55) via the rotating table support cylinder (65). ) Is displaced. This displacement is transmitted to the trunnion shaft (7) via the trunnion shaft interlocking mechanism (54b, 54, 54a, 56, 7a) to increase and decrease the speed. Further, when the forward / reverse switching lever (5) is operated from this state, the rotating base (55) is rotated about the vertical axis (X) by the first engagement pin (53p), and the operation of the transmission lever (6) is maintained. In this state, the trunnion shaft (7) is switched between the forward range (F) and the reverse range (R).

In the invention according to the first to third aspects, in the work that requires fine vehicle speed adjustment, the vehicle speed can be adjusted steplessly with the shift lever (6), and in the work that repeats forward and backward movement, Since the forward / reverse switching operation can be performed by the forward / reverse switching lever (5) as in the case of the vehicle having the gear transmission, the operability is good for both types of work. In addition, when these interlocking mechanisms (L) are mechanically configured, they can be configured at a lower cost than those configured by electric and hydraulic devices such as sensors and actuators.

  In the second aspect of the invention, since the operation amount of the speed change lever (6) is proportional to the increase / decrease amount of the output rotation speed, the vehicle speed fluctuates suddenly with a slight operation amount, or the vehicle speed does not change even if the swing operation is greatly performed. A good operational feeling is obtained by eliminating operational discomfort such as not changing so much.

Hereinafter, the form which mounted this invention on the agricultural tractor is demonstrated based on drawing.
First, the overall configuration of the tractor T will be described.
1 to 4, the tractor T is provided with an engine E in the hood 11 at the front of the vehicle body, and the rotational power of the engine E is transmitted to the transmission case 12 (from the front, the clutch housing 12A, the spacer case 12B, the transmission It is configured to transmit to the left and right front wheels 2 and 2 and the left and right rear wheels 3 and 3 as a traveling device via a transmission mechanism in the case 12C). Further, a cylinder case 15 is provided in the rear upper part of the transmission case 12C. The lift case 14 and 14 are pivotally attached to the left and right sides of the cylinder case 15, respectively. The lift arms 14 and 14 are turned up and down by a piston expansion / contraction operation of the cylinder 13. Further, a three-point link mechanism comprising a top link and left and right lower links is provided at the rear part of the transmission case 12C, and various work machines are connected to the link mechanism.

  A handle column 17 is erected on the rear side of the engine E, and a steering handle 19 is protruded and supported on the column 17, and a so-called shuttle operation type forward / backward movement is performed to switch the advancing direction of the vehicle body to the column side. A switching lever 5 is provided so as to move back and forth along the lever guide. The forward / reverse switching lever 5 is positioned at three operation positions of “forward”, “neutral”, and “reverse” in the locking groove of the lever guide.

On the floor 20 below the handle 19, left and right brake pedals 21L and 21R, a clutch pedal 22, and an accelerator pedal are provided.
Further, a cockpit 2 is provided behind the handle 19, and a position lever 18 for continuously rotating the lift arm 14 and a continuously variable transmission on a fender 23 on the side of the cockpit 2 as shown in FIG. A shift lever 6 for adjusting the output rotational speed of the device (hereinafter referred to as HST) 3 and a sub shift lever 27 for switching the shift position of the sub transmission are provided.

Next, the power transmission configuration of the tractor T will be described with reference to FIG.
The rotational power output from the engine E is transmitted to the pump input shaft 31 of the HST 3 serving as a continuously variable transmission through the main clutch 30 that is turned on and off by the depression operation of the clutch pedal 22. Is done. The rotation input to the HST pump 3p is output from the motor output shaft 32 of the HST motor 3m in accordance with the operation angle of the trunnion shaft 7 described later.

  As shown in FIG. 5, the HST 3 is arranged with the trunnion shaft 7 of the HST pump 3p protruding upward at the vehicle body left and right center position, and the HST motor 3m is provided on the left and right sides of the pump 3p. It has become.

  The rotational power output from the motor output shaft 32 is transmitted to a constant mesh gear sub-transmission device 33 capable of three-speed shifting of L, M, and H, and the rotation shifted by the transmission device is transmitted to the rear wheel differential. This is transmitted to the left and right rear wheels 1R and 1R via the mechanism 34, and is also transmitted to the left and right front wheels 1F and 1F via the front wheel increasing mechanism 35 and the front wheel differential mechanism 36.

  Further, the rotational power of the engine E is transmitted to a PTO shaft 38 projecting from the rear surface of the transmission case 12C via a PTO forward / reverse switching mechanism and a PTO transmission.

Note that reference numeral 39 in the drawing indicates left and right rear wheel brakes that are braked by a depression operation of the brake pedal 21L (21R) or a piston expansion / contraction operation of a hydraulic cylinder.
Next, the hydraulic circuit configuration of the tractor will be described with reference to FIG.

  The tractor T is provided with first and second hydraulic pumps P1 and P2, and each pump is configured to suck up hydraulic oil / lubricating oil filled in the transmission case 3 and send it to each hydraulic actuator. . The first pump P1 is configured such that pressure oil is sent to the power steering oil passage L19 on the upper side of the circuit, and this surplus oil is fed as charge oil into the closed circuit L3 of the HST3. The second pump P <b> 2 is configured to send pressure oil to the working machine lifting / lowering hydraulic cylinder 13 via the switching control valve 39.

  In the figure, reference numeral 7 denotes a trunnion shaft for operating the swash plate of the HST pump 3p. The neutral position is forward / reverse, that is, the vehicle is operated in conjunction with the forward or reverse side. The engine is operated over the forward region F and the reverse region R across the position N, and the output rotational speed is changed from small to large as the rotational angle from the neutral position N increases. In the figure, reference numeral 40 denotes an oil cooler, and 41 denotes a filter.

Next, a description will be given of the structure of the HST3 speed change operation device, which is a main part of the present invention.
This speed change operation device includes the forward / reverse switching lever 5, the speed change lever 6, and a lever interlocking mechanism (interlocking mechanism) L provided in the spacer case 12B.

  Specifically, as shown in FIG. 7, the base portion of the forward / reverse switching lever 5 is interlocked and connected to the interlocking arm 51 on the upper surface of the clutch housing 12 </ b> A via the interlocking shaft 50 in the handle column 17. The forward / reverse input arm 52 protruding from the upper surface of the case 12B is connected via an expansion / contraction adjustment rod 53A serving as a length adjustment tool. Thereby, the turning operation force around the interlocking shaft 50 is transmitted to the forward / reverse input shaft 53 via the interlocking arm 51, the expansion / contraction adjusting rod 53A, and the input arm 52, and the forward / backward input shaft 53 can be rotated forward and backward. It is a configuration. In addition, by adjusting the length of the telescopic adjustment rod 53A, the rotational position of the forward / reverse input arm 52 can be adjusted, and the neutral position of the trunnion shaft 7 of the HST 3 to be described later can be adjusted.

  As shown in FIG. 8, the forward / reverse input arm 52 is attached to a forward / reverse input shaft 53 that passes through the spacer case 12B and is arranged in the vertical direction. It is rotatably supported by a cylindrical shaft 54 having two arm pieces (hereinafter referred to as an upper interlocking arm 54a and a lower interlocking arm 54b), and an arm piece (hereinafter referred to as a forward / reverse switching arm 53a) is provided at the lower end of the same axis. It is configured to be fixed.

  Further, a first engaging pin 53p protruding downward is provided at the tip of the forward / reverse switching arm 53a, and a second protrusion protruding downward also at the tip of the lower interlocking arm 54b of the cylindrical shaft 54 is provided. An engagement pin 54p is provided. Both pins 53p and 54p are configured to be locked in the first and second locking grooves 55a and 55b of the rotary base 55 disposed below the forward / reverse input shaft 53.

  The turntable 55 has a longitudinal axis X parallel to the forward / reverse input shaft 53 and is disposed in the vicinity of the input shaft 53, and the turntable 55 is sandwiched between the neutral position as the first engagement pin 53p swings. The posture is changed to the forward-side interlocking posture (a) and the reverse-side interlocking posture (b). That is, since the first engagement pin 53p is engaged with the first locking groove 55b of the turntable 55, the swinging motion of the first engagement pin 53p rotates the turntable 55 around the vertical axis X. Thus, the position is switched to the forward-side or reverse-side interlocking posture (a) (b) (FIG. 9B).

  The upper interlocking arm 54a is rotatably connected to the trunnion shaft operating arm 7a integral with the trunnion shaft 7 via the interlocking plate 56, and includes a lower interlocking arm 54b, a cylinder shaft 54, and an upper interlocking member. The arm 54a, the interlocking plate 56, and the trunnion shaft operating arm 7a constitute a trunnion shaft interlocking mechanism.

  On the other hand, the base of the speed change lever 6 is connected to the speed change input shaft 63 via an interlocking shaft inside the fender 23. The shift input shaft 63 is provided with a shifter arm 63a fixed to the tip of the shaft, and the arm 63a is engaged with a turntable support cylinder 65 so that the turntable 55 can be moved back and forth. That is, the turntable support cylinder 65 is configured to be slidable back and forth along a support shaft 64 having an axial center in the front-rear direction.

  The sliding movement of the turntable support cylinder 65 is to move the turntable 55 back and forth linearly. For example, when the turntable 55 moves to the front side in the forward movement interlocking posture (a), the oblong hole shape is formed. The locking groove 55a moves in parallel and the second engagement pin 54p fitted to the locking groove 55a slides and moves. However, since the movement is restricted by the directionality of the locking groove 55a, the second engagement pin 54p. For example, when the shifter arm 63a moves from Smin toward Smax in FIG. 10A, the movement in the clockwise direction about the vertical axis X as shown by the phantom line from the solid line in FIG. Accordingly, the upper interlocking arm 54b is interlocked clockwise in FIG. 10C, thereby pushing the interlocking plate 56 and swinging the trunnion shaft 7 from the neutral position N to the forward range F. On the contrary, when the shifter arm 63a moves from Smax toward Smin, the trunnion shaft 7 is returned to this position within the range of the forward travel region F with the neutral position N as a limit.

  Further, when the turntable 55 is in the reverse geared linkage position (b) and the shifter arm 63a moves from Smin toward Smax, the second engagement pin 54p is counterclockwise as shown in FIG. When the upper interlocking arm 54b is rotated counterclockwise in FIG. 11C in conjunction with this, the interlocking plate 56 is pulled to move the trunnion shaft operating arm 7a from the neutral position N to the reverse range R. Oscillate. On the contrary, when the shifter arm 63a moves from Smax to Smin, the trunnion shaft 7 is returned to this position within the range of the reverse travel region R with the neutral position N as a limit.

  As described above, the sliding movement of the turntable support cylinder 65 is due to the swinging motion around the fulcrum of the shifter arm 63a that is linked to the swinging motion of the shift lever 6 in the longitudinal direction. Further, the slide movement interlocks with the second engagement pin 54p and rotates the trunnion shaft 7 in the range of the forward range F or the reverse range R. However, the rotation amount of the trunnion shaft 7 is proportional to the forward / backward swing amount of the speed change lever 6. Thus, in the present embodiment, the rotation range around the fulcrum of the shifter arm 63a is rotated in a position slightly shifted to the front side (rotation in the range of angle α) (rotation in the range of angle β). ) (FIG. 13). As a result, as shown by the solid line in FIG. 14, the rotation amount of the trunnion shaft 7 changes substantially in proportion to the operation amount of the speed change lever 6. For this reason, the speed can be changed approximately proportionally from the side closer to the neutral position of the speed change lever 6 to the side away from it, and the operating feeling is improved. That is, since the operation amount of the speed change lever (6) is proportional to the increase / decrease amount of the output rotation speed, the vehicle speed fluctuates suddenly with a slight operation amount, or the vehicle speed does not change so much even if it is greatly swung. The above feeling of incongruity can be eliminated and the operational feeling is improved.

Note that, as shown by the dotted line in FIG. 14, the above-described front-rear sorting arrangement is dangerous because the speed suddenly increases.
Further, the amount of deviation between the angle α (turning within the range) and the angle β (turning within the range) affects the effective length of the shifter arm 63a, the turning amount around the fulcrum, the link ratio of the subsequent interlocking mechanism, and the like. As described above, by adjusting the movement of the rotation amount of the trunnion shaft 7 according to the adjustment setting of the circumferential mounting position of the shifter arm 63a with respect to the transmission input shaft 63, the operation of the transmission lever 6 and the front and rear The movement of the turntable 55 that fuses the operation of the advance switch lever 5 can be directly controlled, and the adjustment can be easily performed. The specific configuration of the adjustment is that the shifter arm 63a can be fixed at a predetermined position on the outer periphery of the shift operation input shaft 63 by serration fitting the shift operation input shaft 63 and the shifter arm 63a. In addition to serration fitting, it may be configured to be fixed by pressing with a set bolt.

In addition, it is the structure which fastens the support metal 63b which supports the transmission operation input shaft 63 with a volt | bolt with respect to a mission case.
In addition, the code | symbol 66 in FIG. 8 shows the attachment bracket which attaches the member with which the said support shaft 64 is equipped to the corner part of spacer case 12B.

  Further, the alternate long and short dash line Smin described in the shift input shaft 63 indicates the position of the shifter arm 63a when the shift lever 6 is set to the lowest speed position, and the alternate long and short dash line Smax indicates when the shift lever 6 is set to the highest speed position. The position of the shifter arm 63a is shown.

  The lever interlocking mechanism L configured as described above rotates and holds the forward / reverse switching lever 5 in the “forward” position, the “neutral” position, and the “reverse” position, so that the forward / reverse input shaft 53 and the forward / reverse switching are performed. The arm 53a is rotated, and the positions of the first engagement pins 53p provided on the arm 53a are respectively positioned at positions corresponding to the “forward” position, the “neutral” position, and the “reverse” position. Thereby, the angle of the turntable 55, specifically, the initial position at the forward, reverse and neutral positions is set. That is, the position with respect to the trunnion shaft 7 is changed. When the shift lever 6 is operated back and forth at the respective initial positions, the shift input shaft 63 and the shifter arm 63a are rotated, and the turntable support cylinder 65 is slid on the support shaft 64. As a result, the engaging pin 54p and the cylinder shaft 54 rotate, and the rotational position of the trunnion shaft 7 is changed through the interlocking of the upper interlocking arm 54a, the interlocking plate 56, and the trunnion shaft operating arm 7a. Therefore, the rotational power output from the HST motor 3m is shifted, and the vehicle speed is shifted.

The action of each state will be specifically described.
FIG. 12 shows the lever interlocking mechanism L in which the forward / reverse switching lever 5 is set to the “neutral” position and the transmission lever 6 is set to the “lowest speed” position. In this case, the rotary base 55 and the support shaft 64 are in a substantially parallel state in plan view, and the pin 53p integrated with the forward / reverse input shaft 53 and the coaxial 53 and the pin 54p of the tube shaft 54 are arranged on a substantially straight line. Therefore, even if the speed change lever 6 is rotated to the high speed or low speed side, both the pins 53p and 54p only move within the locking groove 55a of the turntable 55 without frictional resistance, and the lower interlocking arm 54b is rotated. Maintain a moving angle. Therefore, the configuration in which the operation of the shift lever 6 is not transmitted to the trunnion shaft 7, that is, the shift operation is invalidated.

  FIG. 10 shows a state in which the forward / reverse switching lever 5 is set to the “forward” position and the transmission lever 6 is set to the “lowest speed” position. In this case, the first engagement pin 53p of the forward / reverse switching arm 53a is separated from the support shaft 64 in a plan view ((C) in FIG. 10) than when the "neutral" position is set. Set to position. When the speed change lever 6 is turned to the high speed side, the turntable 55 is slid forward on the support shaft 64 along with the turn of the speed change input shaft 63, and the pin 53 p is a locking groove of the turntable 55. By sliding frictionally in 55a, the pin 54p and the cylindrical shaft 54 integrated therewith rotate, and the trunnion shaft 7 is moved forward through the movement of the upper interlocking arm 54a, the connecting plate 56, and the trunnion shaft mounting arm 7a. Rotate in the area. Therefore, the vehicle is shifted in the forward range.

  FIG. 11 shows a state in which the forward / reverse switching lever 5 is set to the “reverse” position and the transmission lever 6 is set to the “lowest speed” position. In this case, the first engagement pin 53p of the forward / reverse switching arm 53a is closer to the support shaft 64 than when it is set to the "neutral" position in plan view ((c) in FIG. 11). Set to position. When the speed change lever 6 is turned to the high speed side, the turntable 55 is slid forward on the support shaft 64 along with the turn of the speed change input shaft 63, and the pin 53 p is a locking groove of the turntable 55. By sliding frictionally within 55a, the pin 54p and the cylindrical shaft 54 integral therewith rotate, and the trunnion shaft 7 is operated backwards through the movement of the upper interlocking arm 54a, the connecting plate 56, and the trunnion shaft mounting arm 7a. Rotate in the area. Therefore, the vehicle is shifted in the reverse range.

  In addition, when the forward / reverse switching lever 5 is operated to the reverse side from the state of the imaginary line in FIG. The turntable 55 is switched to the reverse-side interlocking posture (b) via the stop groove 55b. At this time, the turntable support cylinder 65 does not move, and the turntable 55 can be rotated from the solid line state of FIG. Accordingly, the second engagement pin 54p is greatly displaced from the solid line position in FIG. 9B to the state indicated by the phantom line, and the trunnion shaft (7) is moved from the forward movement area (F) beyond the neutral position to the reverse movement area (R). It moves quickly to a predetermined speed. Since the operator only switches the forward / reverse switching lever 5 and does not require the operation of the shift lever 6, it is suitable for loader work that frequently repeats forward and reverse.

The output rotation direction can be switched between the normal rotation direction and the reverse rotation direction based on the switching operation of the forward / reverse switching lever 5, but when changing the speed, the output rotation direction is the normal rotation direction or the reverse rotation direction. When the shift lever 6 is operated backward, the speed can be reduced, and when operated forward, the speed can be increased. In the lever interlocking mechanism L, the forward / reverse switching arm 53a is slightly angled with respect to the support shaft 64 so as to move forward / backward. When the switch lever 5 is set to the “neutral” operation, the pin 53p is displaced to the “forward” position so that the forward / reverse switch lever 5 is set to the “reverse” position than the “forward” position. The speed change range is narrow and the vehicle speed is set not to be high.

  The HST speed change operation device configured as described above can adjust the vehicle speed steplessly with the speed change lever 6 in the work that requires fine adjustment of the vehicle speed, and in the work that repeats forward and backward movements as usual. Since the forward / reverse switching operation can be performed by the forward / reverse switching lever 5 as in the case of the vehicle having the gear type transmission, the operability is good for both types of work. In addition, since these interlocking mechanisms are configured by mechanical interlocking mechanisms, the operation device can be configured at a lower cost compared to configuring the operation device by electric or hydraulic equipment such as sensors and actuators.

  In the lever interlocking mechanism L, the forward / reverse switching lever 5 is operated to the “forward” position or the “reverse” position to engage the clutch and simultaneously start the vehicle. Compared with a configuration in which the vehicle does not start unless it is operated separately, the operation position is less likely to be mistaken and the work can be started quickly.

Next, the mounting structure of the lever interlocking mechanism L will be described based on FIG. 15 and others.
The bracket 66 includes mounting holes 66f and 66r at the front and rear portions, and the mounting holes 66f and 66r are mounted to the wall surface of the corner portion in the spacer case 12B with bolts. Further, the case 12B is configured to be filled with lubricating oil and HST hydraulic oil up to the height of the line X.

  Thereby, since a part of the lever interlocking mechanism L, specifically, the level of the turntable 33 is immersed in the lubricating oil, it is possible to prevent malfunction due to wear. Further, in the lever interlocking mechanism, in detail, the lower transmission member below the forward / reverse input shaft 53 and the speed change input shaft 63 can prevent malfunction due to contact with foreign matter or corrosion.

  The slide movement of the turntable support cylinder 65 can be performed by supporting the turntable support cylinder 65 on the support shaft 64 in the front-rear direction, but in the embodiment of FIG. The support for the turntable support cylinder 65 can be performed stably.

  Although the rotation angle of the trunnion shaft 7 with respect to the rotation operation amount of the shift lever 6 can be set to a predetermined value by configuring the shifter arm 63a with a different mounting angle with respect to the operation rotation input shaft 63, this fulcrum position Can be adjusted and set from the outside of the transmission case by attaching and detaching the support metal 63b, so that it is possible to adjust and set the operating feeling of the shift lever 6 and the rotation amount of the trunnion shaft 7, and the operator's favorite operating feeling can be set. Obtainable. For example, when the vehicle is traveling at a low speed, the trunnion shaft 7 rotation of a predetermined angle θ is obtained with a small swinging operation amount x of the speed change lever 6, while on the other hand, when the speed is high speed, a predetermined swinging operation amount y (> x) of the speed change lever 6 is predetermined. When the rotation of the trunnion shaft of the angle θ is set to obtain 7 rotations, even if the shift lever 6 swinging operation at high speed is large, the shift increase amount is small, so that a rapid increase in speed is prevented (one point in FIG. 14). Chain line). On the other hand, when there are many opportunities for the shift lever 6 to travel at a high speed position by a highly skilled operator, a trunnion shaft 7 rotation of a predetermined angle θ is obtained with a large swing operation amount y during low speed travel. On the other hand, when the vehicle is traveling at high speed, the rotation lever 7 is set so as to obtain 7 rotations of the trunnion shaft at a predetermined angle θ with a small swing operation amount x (<y). Sensitive operation feeling can be obtained by setting the high-speed operation side sensitively (two-dot chain line in the figure).

  FIG. 16 (D) relates to an improvement in the connection configuration between the interlocking plate 56 and the trunnion shaft operating arm 7a, and a pin member 7b protruding from the operating arm 7a side is formed in the longitudinal direction of the plate 56 on the interlocking plate 56 side. The long holes 56a to be fitted are interlocked with each other. With this configuration, even if the linkage mechanism of the interlocking plate 56 is bent or rattled, this can be absorbed and the neutral return mechanism 7c (spring, ball, etc.) that acts on the trunnion shaft operating arm 7a is followed. A neutral position can be secured, and there is no danger of the body moving unexpectedly.

  FIG. 17 relates to an improvement of a fuel supply tank stand. A support frame 70 composed of a horizontal frame 70a and a vertical frame 70b is detachably fixed to the side of the frame portion of the vehicle body, and a fulcrum pin 71 is attached to the upper portion of the support frame 70 in a horizontal posture. A pedestal 72 formed in a rectangular shape in plan view is attached to the fulcrum pin 71 so as to be rotatable up and down. A support hook 73 is pivotally attached to the pedestal 72 side, and a recess 73a formed at the distal end is provided to be detachable from a support pin 74 fixed to the vertical frame 70b side. When the support hook 73 is engaged with the support pin 74 as shown in the figure, the cradle 72 can be held in a horizontal position, and the oil supply tank 75 is placed to perform the oil supply operation. When storing, the support hook 73 is removed, and the hook 73 is set in a storage state along an appropriate inner wall of the pedestal 72. Reference numeral 76 denotes a magnet for holding the hook 73 in a stored state. The support frame 70 can be used as a support frame for the mirror 77.

The whole tractor side view. Side view of each mission case. The top view which shows arrangement | positioning of each lever on a fender. Tractor transmission mechanism diagram The front view of a mission case. Hydraulic circuit diagram. The top view of a mission case. The perspective view of the lever interlocking mechanism which made the forward / backward movement the neutral position and made the gear shift position the lowest speed position. (A) The perspective view of the lever interlocking mechanism which made the forward / backward movement the reverse drive position and made the speed change position the highest speed position. (B) The same plane sectional view. (A) The side view of the lever interlocking mechanism which made the forward / rearward movement the forward position and the shift position the lowest speed position. (B) Front view of the lever interlocking mechanism. (C) The top view of a lever interlocking mechanism similarly. (D) The perspective view of a lever interlocking mechanism similarly. (E) The cross-sectional view of the lever interlocking mechanism. (A) The side view of the lever interlocking mechanism which made the forward / backward movement the reverse drive position and the speed change position the lowest speed position. (B) Front view of the lever interlocking mechanism. (C) The top view of a lever interlocking mechanism similarly. (D) The perspective view of a lever interlocking mechanism similarly. (E) The cross-sectional view of the lever interlocking mechanism. (A) The side view of the lever interlocking mechanism which made the forward / backward movement the neutral position and made the speed change position the lowest speed position. (B) The front view of the lever interlocking mechanism which made the forward / backward movement the neutral position and made the speed change position the lowest speed position. (C) The top view of the lever interlocking mechanism which made the forward / backward movement the neutral position and made the gear shift position the lowest speed position. The interlocking mechanism partial side view. Operation rotation input shaft angle-trunnion shaft angle relationship graph. The perspective view which fractured | ruptured the mission case which shows the attachment state of a lever interlocking mechanism. (A) Front view showing partially different interlocking mechanisms, (B) side view, (C) plan view, (D) partially enlarged plan view. (A) The front view which shows an example of a fuel tank stand, (B) Side view, (C) Plan view, (D) The accommodation state front view.

Explanation of symbols

E Engine L Lever interlocking mechanism (interlocking mechanism)
T tractor 1F front wheel 1R rear wheel 3 HST
5 Forward / reverse switching lever 6 Shift lever 7 Trunnion shaft 7a Trunnion shaft operation arm (operation arm)
12 Transmission case 53p First engagement pin 54a Forward / reverse switching arm (interlocking arm)
54p 2nd engagement pin 55 Turntable 63 Operation rotation input shaft 63a Shifter arm

Claims (3)

  The continuously variable transmission (3) that transmits the rotational power of the engine (E) to the traveling devices (1F, 1R), the continuously variable transmission (3), and the output rotational speed of the continuously variable transmission (3) Based on the switching operation of the speed change lever (6) and the forward / reverse switching lever (5), the output rotation direction of the continuously variable transmission (3) with respect to the same operation direction of the speed change lever (6) is defined as the forward rotation direction. A speed change operation device for a work vehicle, characterized in that an interlocking mechanism (L) capable of switching in a reverse direction is provided. The continuously variable transmission (3) that transmits the rotational power of the engine (E) to the traveling devices (1F, 1R), the continuously variable transmission (3), and the output rotational speed of the continuously variable transmission (3) Based on the switching operation of the speed change lever (6) and the forward / reverse switching lever (5), the output rotation direction of the continuously variable transmission (3) with respect to the same operation direction of the speed change lever (6) is defined as the forward rotation direction. An interlocking mechanism (L) that can be switched in the reverse direction is provided.
The interlocking mechanism (L) is a speed change operation device in a work vehicle configured to make the output rotational speed of the continuously variable transmission (3) substantially proportional to the speed change operation amount of the speed change lever (6). The interlocking mechanism (L) includes a first engagement pin (53p) and a second engagement groove (55a) that engage with the first engagement groove (55b), the engagement groove (55b), and the engagement groove ( 55a) and a rotating base (55) provided with a second engaging pin (54p) that engages with the second engaging pin (54p), and supports the rotating base (55) so as to be rotatable about the vertical axis (X). ) And the displacement of the second engagement pin (54p) accompanying the reciprocating movement of the rotating table (55) to the trunnion shaft (7). Trunnion shaft interlocking mechanism (54b, 54, 54a, 56, 7a)
The turntable support cylinder (65) is configured to reciprocate in conjunction with the operation of the speed change lever (6),
By rotating the first engagement pin (53p) in conjunction with the operation of the forward / reverse switching lever (5), the turntable (55) is rotated about the vertical axis (X), thereby the trunnion shaft (7 3. The work according to claim 1 or 2, wherein the rotatable range is switched from the forward range (F) to the reverse range (R), or from the reverse range (R) to the forward range (F). A speed change operation device in a vehicle.

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