JP3542110B2 - Traveling gear operating device for work vehicles - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a traveling speed change operation device for a work vehicle in which an operation portion of a continuously variable transmission that transmits power to a traveling device is linked with a manually operated shift lever.
[0002]
[Prior art]
Conventionally, in the above-mentioned work vehicle, as disclosed in, for example, Japanese Patent Application Laid-Open No. 5-58183, a spring ball which can be freely disengaged from a vertically long hole of a horizontally long guide plate is provided with a switching lever interlocking with an operation trunnion shaft of a continuously variable transmission. In some cases, positioning is performed by cooperation between a position holding mechanism having a friction plate and a friction holding mechanism having a friction plate.
[0003]
[Problems to be solved by the invention]
For example, when working by connecting a tillage device with an agricultural tractor or when traveling on a headland or a road, the vehicle runs at a high speed, and when working with a trencher or the like, the vehicle runs at a low speed. In the case of high-speed traveling, even if the traveling speed changes slightly, the work and traveling are hardly affected, whereas in the case of low-speed traveling, if the traveling speed is slightly increased from an appropriate speed, the work load increases significantly and the finish is finished. A change in running speed tends to greatly affect work and running, for example, when driving becomes worse or when driving becomes difficult.
In the above-described conventional shift technology, even when the shift lever as the shift lever is operated in any part of the lever operation range, the position holding mechanism by the spring ball and the friction holding mechanism cooperate to operate the stepped operating position. The continuously variable transmission is held in a stepped speed state. For this reason, conventionally, when performing low-speed traveling, the continuously variable transmission cannot be held at an appropriate speed state, or when performing a shift operation, the speed state of the continuously variable transmission is excessively changed, and the work finish is deteriorated. In some cases, it became difficult to drive.
SUMMARY OF THE INVENTION An object of the present invention is to provide a traveling speed change operation device for a work vehicle that can perform high-speed traveling while performing a stepped gear shift while preventing the shift lever from vibrating or rattling, and can advantageously perform work while traveling at low speed. Is to do.
[0004]
[Means for Solving the Problems]
The configuration, operation and effect of the invention according to claim 1 are as follows.
[0005]

〔Constitution〕
In a traveling shift operating device of a work vehicle, an operation unit of a continuously variable transmission that transmits power to the traveling device is linked with a manually operated shift lever.
Frictionless position holding means acting on the shift lever to hold the shift lever in the operating position by friction when the continuously variable transmission is in either the low speed range or the high speed range; and And only when in the high speed range of the high speed range, locking type position holding means acting on the shift lever to hold the shift lever in the operating position by entry of the locking body into the positioning recess,
The shift lever is swingably supported, and the locking body is attached to the shift lever so as to move with respect to the shift lever in a direction intersecting the swing axis of the shift lever. The positioning member provided is swingably supported around an axis parallel to the swing axis of the shift lever,
A long hole elongated in a moving direction of a speed change lever provided on the positioning member, a support shaft attached to the speed change lever so as to be movably inserted through the long hole, and a positioning member; And a friction member supported by the support shaft in a state of being pressed against the shaft.
[0006]
[Action]
When the continuously variable transmission is operated in the low speed range and the vehicle is traveling at low speed, the shift lever is held at the position by the friction type position holding means. The vehicle can travel while continuously changing the speed of the traveling device while maintaining the speed state of the steps. When the continuously variable transmission is operated in a high speed range and traveling at high speed, the shift lever is held by the locking type position holding means and the friction type position holding means, so the shift lever is held at the stepped operation position. The stepless transmission is held at a stepped speed state determined by the operation position of the shift lever held by the locking type position holding means, and the traveling device is stepped while the shift lever is vibrated or rattled. The vehicle can travel while being held by the frictional position holding means so as not to be easily attached.
When the positioning member is a fixed type, the positioning recess moves together with the transmission lever, depending on whether there is an error in manufacturing or assembling the positioning member, or whether the transmission lever and the positioning member are supported by different members. May not be aligned with the movement locus with high accuracy. Then, it becomes easy for the twisting to occur between the locking body and the positioning member that moves together with the shift lever, or the angle of the inclined inner surface of the positioning recess with respect to the shift lever varies depending on the operation position, and the operating resistance applied to the shift lever is reduced. A situation that changes depending on the operation position is likely to occur. However, the positioning member is supported so as to be able to swing around an axis parallel to the swing axis of the shift lever, and its free end is in a state of being connected to the shift lever via a locking member or the like. Thus, even if there is an error in manufacturing or assembling the positioning member, or if the positioning member and the positioning member are supported by different members, the positioning member swings as the shift lever moves, and the locking member is locked. The locking body is moved together with the shift lever while preventing the twisting from occurring between the body and the positioning member, and making the angle of the inclined inner surface of the positioning recess to the shift lever constant or almost constant regardless of the change of the operation position. It can be moved or disengaged from the positioning recess.
[0007]

〔effect〕
When traveling at high speed, the continuously variable transmission can be stepped while maintaining the stepped speed state, and the shift lever is held by the friction type position holding means, so that vibration and rattling of the shift lever are easily avoided. In addition, when traveling at a low speed, the continuously variable transmission is maintained at a stepless speed state, the traveling speed is changed steplessly, and the traveling speed is appropriately set or adjusted according to the work to achieve a good finish. Can work.
Even if there is an error in manufacturing or assembling the positioning member, or if the shift lever and the support member of the positioning member are different, it is possible to prevent the twisting between the locking body and the positioning member from being easily caused, or to reduce the inclination of the inner surface of the positioning recess. Good operability such that the angle with respect to the shift lever is constant or almost constant regardless of the change in the operation position, so that the shift lever moves smoothly, or the operating resistance due to engagement and disengagement of the locking body is unlikely to change. The gear can be operated in the state.
[0008]
The configuration, operation and effect of the invention according to claim 2 are as follows.
[0009]

〔Constitution〕
In the configuration of the invention according to claim 1, the continuously variable transmission is a hydrostatic continuously variable transmission.
[0010]
[Action]
In the case of a hydrostatic continuously variable transmission, it is driven while leaking oil, and the ratio of this leak is larger in low-speed running than in high-speed running. In addition, as the running load increases, the amount of leak increases, and when the running load is high, the vehicle is driven at a low speed. For this reason, in the case of low-speed traveling, speed changes are likely to occur.However, the speed of the continuously variable transmission is steplessly maintained, and traveling is performed while finely adjusting the traveling speed to an appropriate speed according to the work. it can.
[0011]

〔effect〕
As a continuously variable transmission, a hydrostatic continuously variable transmission is adopted so that the gear can be easily shifted to both the forward side and the reverse side. When working while traveling at low speed while traveling while reliably holding in the predetermined operation position by the locking type position holding means, traveling while setting or adjusting the traveling speed to an appropriate one according to the work Work can be done with a good finish.
[0012]
The configuration, operation and effect of the invention according to claim 3 are as follows.
[0013]

〔Constitution〕
In the structure of the invention according to claim 2, the friction type position holding means acts on the shift lever when the continuously variable transmission is in a low speed range and a high speed range on both the forward and backward movements, and the locking type position holding means is provided. The means acts on the shift lever when the continuously variable transmission is in the high-speed region on both the forward and backward directions.
[0014]
[Action]
When the continuously variable transmission is operated to the forward side, even when operated to the reverse side, when the continuously variable transmission is operated in the low speed range and running at low speed, the shift lever is held in position by the friction type position holding means, By keeping the continuously variable transmission at a continuously variable speed state, the traveling device can travel while continuously variable transmission. When the continuously variable transmission is operated at a high speed range to travel at high speed, the shift lever is held in position by the locking type position holding means and the friction type position holding means, and the continuously variable transmission is held at a stepped speed state. Therefore, the vehicle can travel while the transmission device is being steppedly shifted and the transmission lever is held by the friction type holding means so as to be less likely to vibrate or rattle.
[0015]

〔effect〕
Regardless of whether traveling forward or backward, when traveling at high speed, it is possible to travel while avoiding vibration and rattling of the shift lever, while holding the shift lever in a predetermined operation position while stepped shifting, When traveling at a low speed, the vehicle can travel while changing the traveling speed steplessly and appropriately setting or adjusting to a desired speed.
[0016]
[0017]
[0018]
[0019]
[0020]
[0021]
[0022]
[0023]
[0024]
[0025]
[0026]
[0027]
[0028]
The configuration, operation and effect of the invention according to claim 4 are as follows.
[0029]

〔Constitution〕
Te configuration smell invention according to any one of claims 1 to 3, a pre-SL slot, is formed in an arc shape viewed in the direction along the pivot axis of the shift lever.
[0030]
[Action]
When the shift lever is operated, the support shaft of the friction member moves relative to the positioning member along the arc-shaped long hole of the positioning member, and the friction type position holding means supports the free end side of the positioning member, With this support, the positioning member maintains the posture in which the locking body smoothly engages and disengages from the positioning recess.
[0031]

〔effect〕
The positioning member is maintained in an appropriate posture by the friction type position holding means, so that the shifting operation can be performed with good operability in which the locking body is smoothly engaged with and disengaged from the positioning recess. In addition, the structure can be obtained simply by utilizing the friction type position holding means as means for connecting the free end side of the positioning member to the speed change lever.
[0032]
BEST MODE FOR CARRYING OUT THE INVENTION
As shown in FIG. 1, a pair of left and right steering wheels 1 and 1 that can be steered and driven freely, a pair of left and right drivable rear wheels 2 and 2, an engine 3 and a radiator 4 for cooling the engine are provided. Various operations such as a rotary tilling device are provided on a rear portion of a transmission case 7 which forms a rear portion of a vehicle body having a driving portion, a driving portion provided with a steering handle 5 and a driving seat 6 located behind the driving portion. A lift tractor 8 as an example of a working vehicle is provided by providing a lift arm 8 for connecting the device so as to be able to move up and down freely, and a power take-out shaft 9 for transmitting turning power from the engine 3 to the connected working device.
[0033]
A continuously variable transmission 10 for traveling is attached to the front of the transmission case 7. The continuously variable transmission 10 includes a plunger-type variable discharge pump for inputting the rotational output of the engine 3 via a clutch 11 and a rotary transmission shaft 12, and a hydraulic motor driven by pressure oil from the pump. It is configured as a hydraulic stepless transmission. The hydraulic motor transmits the rotation output of the hydraulic motor to an input portion of a gear type traveling mission provided inside the transmission case 7. As a result, the continuously variable transmission 10 uses the rotational power from the engine 3 as the forward-side or reverse-side rotational power, and continuously changes the speed on both the forward side and the reverse side via the traveling transmission. The power is transmitted to the wheels 1 and 2, or the power transmission is stopped.
[0034]
That is, when the continuously variable transmission 10 is shifted by the traveling transmission operation device provided with the transmission lever 13 located on the side of the driver's seat 6, the tractor is switched between forward and backward and traveling stop operation, forward and backward. The speed change is performed on the side.
[0035]
As shown in FIG. 2, the traveling speed change operation device guides the speed change lever 13 and the rear wheel fender 14 linked to the operation portion 10 a of the continuously variable transmission 10 by an interlocking mechanism 20. And the friction type position holding means 50, which act to hold the position of the guide groove 15 and the speed change lever 13 provided on the speed change lever 13. The details are configured as follows.
[0036]
That is, as shown in FIGS. 2 and 7, the speed change lever 13 is a strip member in which a base end 13 a is rotatably connected to a support shaft 16 supported by a lateral side wall of the transmission case 7. A base lever portion 13b, a middle lever portion 13c made of a round bar having a base end portion fixed to the front end portion of the base lever portion 13b, and a base end portion formed of a round bar material at the front end portion of the intermediate lever portion 13c. 13d is constituted by a lever portion 13e made of a round bar material rotatably connected by a connecting pin 17 and each lever portion, and a resin grip member is attached to the tip side of the lever portion 13e. And a spring 18 for urging the tip lever portion 13e to swing laterally outward with respect to the intermediate lever portion 13c around the axis of the connecting pin 17 with respect to the intermediate lever portion 13c. And And, by the grip 13f, 7, are to be swung in the longitudinal direction of the vehicle body around the vehicle transverse axis 16a of the support shaft 16 and along the guide groove 15, such as Figure 8.
[0037]
As shown in FIG. 2, FIG. 3, FIG. 4, etc., the operating portion 10a of the continuously variable transmission 10 is a square shaft portion of a rotary operating shaft 10b for changing the swash plate angle of the hydraulic pump of the continuously variable transmission 10. It is made of a plate-like member whose corners are integrally rotatably connected. As a result, the operation unit 10a swings around the axis of the rotation operation shaft 10b, thereby rotating the rotation operation shaft 10b to change the swash plate angle of the hydraulic pump.
[0038]
The interlocking mechanism 20 includes a connection shaft 21 having one end connected to the operation unit 10a and the other end protruding outside of the vehicle body from a through hole 19a of a center frame 19 forming an intermediate portion of the vehicle body. A swinging link 24 having a base end rotatably connected to a support shaft 22 supported on the outer surface of the lateral side wall portion, and an intermediate portion connected to the connection shaft 21 via a cushion rubber 23; One end of the swing link 24 is rotatably connected to the free end, and the other end of the swing link 24 is rotatably connected to an intermediate portion of the base lever 13b of the transmission lever 13. It is constituted by an interlocking rod 25 that connects the transmission lever 24 and the speed change lever 13 so as to swing together. That is, when the shift lever 13 is rocked, the operation force is transmitted to the operation unit 10a via the interlocking rod 25, the rocking link 24, the cushioning rubber 23, and the connection shaft 21, and the operation unit 10a is rotated by the rotation operation shaft 10b. Rock around the axis of At this time, the cushioning rubber 23 absorbs the vibration of the operation portion 10a and makes it difficult to transmit the vibration to the shift lever 13.
[0039]
Thus, when the shift lever 13 is swung in the front-rear direction of the vehicle body in the operation area A formed by the guide groove 15, the operation portion 10a swings around the axis of the rotary operation shaft 10b due to the operation force. . When the shift lever 13 is operated to a neutral position N located at an intermediate portion in the front-rear direction of the operation area A, the operation portion 10a is set to the neutral position, and the swash plate angle of the motor is set to a neutral angle. When the shift lever 13 is operated to a forward operation area F located on the vehicle body front side of the neutral position N of the operation area A, the operation unit 10a is in the forward position and the swash plate angle of the motor is set to the forward angle. I do. At this time, as the shift lever 13 is moved forward of the forward operation area F, the swing stroke of the operating portion 10a toward the forward side increases, and the operating angle of the swash plate toward the forward side increases. Go. When the shift lever 13 is operated in a reverse operation area R located on the vehicle rear side of the neutral position N in the operation area A, the operation section 10a is in the reverse position and the swash plate angle of the motor is set to the reverse angle. I do. At this time, as the shift lever 13 is moved to the rear side of the reverse operation range R, the swing stroke of the operation portion 10a toward the reverse side increases, and the operating angle toward the reverse side of the swash plate increases. Go.
[0040]
As shown in FIGS. 2 and 5, the locking type position holding means 30 is formed of a plate having one end rotatably connected to a bracket 31 supported by the transmission case 7 by a connecting pin 32. A positioning member 33 supported by the vehicle body so as to be swingable about an axis 32a of the connecting pin 32, which is a lateral axis of the vehicle body and parallel to the oscillation axis 16a of the transmission lever 13, A locking member 34 made of a roller attached to the base lever portion 13b of the lever 13, and the locking member 34 is slidably biased so as to enter the positioning concave portions 35 and 36 of the positioning member 33. It is constituted by a locking spring 37.
[0041]
The positioning member 33 communicates with the locking body long hole 38 into which the locking body 34 is movably inserted, and the locking body long hole 38 above the front end portion of the locking body long hole 38. And a plurality of positioning recesses 35 arranged in the moving direction of the transmission lever 13 and communicating with the locking body long hole 38 above the rear end side portion of the locking body long hole 38. And the plurality of positioning recesses 36 arranged in the moving direction of the transmission lever 13.
[0042]
As shown in FIGS. 5 and 6, one end of a support pin 39 that supports the locking body 34 slidably enters the guide elongated hole 40 of the base lever portion 13b, and the other end of the support pin 39 is A mounting pin 42 connected to the upper end side of a support body 41 supported at the lower end side is slidably inserted into a guide notch 43 of the base lever portion 13b. The locking spring 37 is interposed between the spring receiving portion 13g of the proximal lever portion 13b and the upper end of the support 41, and the support 41 is connected to the guide slot 40 and the guide notch 43. Are urged to slide away from the positioning member 33. As a result, the locking body 34 is supported by the speed change lever 13 so as to be slidable in a direction in which the locking body 34 is engaged and disengaged from the positioning recesses 35 and 36, and is slid by the locking spring 37 so as to enter the positioning recesses 35 and 36. It is being urged.
[0043]
Therefore, when the locking body 34 corresponds to any of the plurality of positioning recesses 35 and 36 by operating the transmission lever 13, the locking body 34 naturally enters the positioning recesses 35 and 36, and the locking body 34 is positioned for this entry. The shift lever 13 is retained at the operation position thereof so as not to be restored to the neutral position N. That is, the continuously variable transmission 10 has a self-restoring force that naturally returns to the neutral state. As shown in FIG. 3, a positioning link 61 swingably supported by a case of the continuously variable transmission 10, a positioning spring 62 for urging the positioning link 61 to swing, and the operating portion 10 a include: A positioning mechanism 60 for positioning the operation unit 10a at a neutral position by pressing a roller 64 of the positioning link 61 against the cam surface 63 of the operation unit 10a by a positioning spring 62 to urge the roller 64. , The operation section 10a. Due to the positioning mechanism 60 and the self-restoring force of the continuously variable transmission 10, the shifting lever 13 has a restoring force for self-return to the neutral position N, but the locking body 34 enters the positioning recesses 35 and 36. The locking between the locking body 34 and the positioning member 33 holds the shift lever 13 in the operating position against the restoring force of the shift lever 13. When the locking body 34 is in the positioning recesses 35 and 36, an operating force equal to or greater than the set force determined by the locking force between the locking body 34 and the positioning member 33 and the frictional force by the friction type position holding means 50 is applied. When applied to the shift lever 13, the locking body 34 is disengaged from the positioning recesses 35, 36 by the operating force and the cam action of the inclined inner surfaces on the front and rear sides of the positioning recesses 35, 36, and the shift lever 13 can be operated. become.
[0044]
Between the positioning recesses 35 on the forward side and between the positioning recesses 36 on the reverse side, it is difficult to position the locking body 34 due to the chevron shape and space of the positioning member 33 in that portion. By not locking to the positioning member 33, the restoring force to the neutral state becomes stronger as the continuously variable transmission 10 moves to a higher speed side. It is difficult to hold at the operation position located between the 36.
[0045]
As a result, the locking type position holding means 30 moves the shift lever 13 operated to the low speed range portion FL close to the neutral position N of the forward operation range F and the low speed range portion RL close to the neutral position N of the reverse operation range R. Does not perform the positioning operation, and performs the positioning operation on the shift lever 13 operated on the high-speed region portion RH of the forward operation region F other than the low-speed region portion FL and on the high-speed region portion RH of the reverse operation region R other than the low-speed region portion RL. I do. In performing this positioning operation, the locking type position holding means 30 prevents the transmission lever 13 from returning to the operation position to the neutral position N when the transmission lever 13 is located at the operation position corresponding to the positioning recesses 35 and 36. The shift lever 13 is not held at the operating position between the positioning recesses 35 and 36. Therefore, the locking type position holding means 30 holds the high-speed region portion FH of the forward operation region F and the high-speed region portion RH of the reverse operation region R by continuously holding the shift lever 13 at the stepped operation position to continuously change the position. The transmission 10 is formed in a stepped speed change range in which a stepped speed state is maintained.
[0046]
As shown in FIGS. 5 and 6, the friction type position holding means 50 includes the positioning member 33, a friction member 51 located on both sides of the positioning member 33, and a positioning member 33 located on one side of the positioning member 33. And a friction spring 52.
[0047]
The two friction members 51 and the friction springs 52 are attached to the base lever portion 13b of the transmission lever 13 in a state in which the support shaft hole 53, which is long in the moving direction of the transmission lever 13 provided in the positioning member 33, is movably inserted. It is supported by a support shaft 54. The friction spring 52 presses and urges the two friction members 51 against the positioning member 33 so that the pair of friction members 51 sandwich the positioning member 33. As a result, the friction members 51 move relative to the positioning member 33 along with the transmission lever 13 along the support shaft hole 53 while being pressed against the positioning member 33, and the transmission lever 13 is operated to any operation position in the operation area A. Also in this case, frictional resistance is given to the shift lever 13 by friction with the positioning member 33.
[0048]
Thereby, the friction type position holding unit 50 operates the low speed region FL of the forward operation region F and the low speed region RL of the reverse operation region R to hold the position by the locking type position holding unit 30. The shift lever 13 that is not performed is held at a position so as not to return to the neutral position N due to friction between the friction member 51 and the positioning member 33, and the low-speed range portions FL and RL are moved to the stepless operation position. The continuously variable transmission 10 is formed in a continuously variable transmission range in which the position is maintained and the continuously variable transmission 10 is maintained in a stepless speed state.
[0049]
When the shift lever 13 is operated in the high-speed region portion FH of the forward operation region F and the high-speed region portion RH of the reverse operation region R and the position is held by the locking type position holding means 30, the locking member 34 The friction type position holding means 30 is driven by the friction between the friction member 51 and the positioning member 33 so that even if there is a play between the positioning member 33 and the shifting lever 13, it is difficult for the shifting lever 13 to swing or vibrate. It acts on the shift lever 13.
[0050]
That is, when the shift lever 13 is swingably operated in the longitudinal direction of the vehicle along the guide groove 15 and is operated to the neutral position N in the intermediate portion in the longitudinal direction of the lever operation area A, the continuously variable transmission 10 is brought into the neutral state. As a result, power transmission to the front and rear wheels 1 and 2 is stopped. At this time, the tip lever portion 13e of the shift lever 13 enters the notch 15A communicating with the guide groove 15 for the swing operation by the spring 18, and the detection switch 70 attached to the inner surface side of the rear wheel fender 14 is operated. It contacts the piece 70a. Then, the detection switch 70 detects that the continuously variable transmission 10 has been operated to the neutral state, outputs a signal for releasing the starting restraint to the engine starting restraint means, and the engine 3 can be started.
[0051]
When the shift lever 13 is operated in the forward operation area F, the continuously variable transmission 10 switches to the forward drive state, and transmits forward drive force to the front and rear wheels 1 and 2. At this time, as the shift lever 13 is operated forward, the continuously variable transmission 10 shifts to the speed increasing side.
When the shift lever 13 is operated in the reverse operation range R, the continuously variable transmission 10 switches to the reverse drive state, and transmits the reverse drive force to the front and rear wheels 1 and 2. At this time, as the shift lever 13 is operated rearward, the continuously variable transmission 10 shifts to the speed increasing side.
In both forward traveling and reverse traveling, when the shift lever 13 is operated in the low speed portions FL and RL to shift the continuously variable transmission 10 in the low speed range, the shift lever 13 is moved by the friction type position holding means 50. , The continuously variable transmission 10 is held in a stepless speed state, and the drive speed of the front and rear wheels 1 and 2 is changed steplessly. When the shift lever 13 is operated at the high speed portions FH and RH to shift the speed of the continuously variable transmission 10 in a high speed range, the position of the shift lever 13 is held by the locking type position holding means 30, and the position of the continuously variable transmission 10 is reduced. Is held at a stepped speed state with a pitch determined by the arrangement of the positioning recesses 35 and 36 of the locking type position holding means 30, and the drive speed of the front and rear wheels 1 and 2 is changed to a stepped state. At this time, the speed change lever 13 is held by the friction type position holding means 50 so that there is no play between the positioning recesses 35 and 36 and the locking body 34.
[0052]
The plurality of positioning recesses 35 and 36 are arranged so as to be arranged in an arc centered on the oscillation axis 16 a of the transmission lever 13 when viewed in a direction along the oscillation axis 16 a of the transmission lever 13. The support shaft hole 53 is formed in an arc shape centered on the swing axis 16a of the transmission lever 13 when viewed in a direction along the swing axis 16a of the shift lever 13. Accordingly, when the locking body 34 and the support shaft 54 relatively move with respect to the positioning member 33, the relative movement is performed in a state where the twisting between the locking member 34 and the supporting member 54 does not easily occur.
[0053]
As shown in FIG. 5, a positioning concave portion 71 is provided in a portion of the positioning member 33 which is located at a central portion in the longitudinal direction of the locking body long hole 38. That is, when the assembling work is performed, the length of the interlocking rod 25 is adjusted such that the operation unit 10a of the continuously variable transmission 10 is located at the neutral position and the locking body 34 of the transmission lever 13 enters the positioning recess 71. It is adjusted by the screw 25a. Then, an assembled state in which the operation position of the shift lever 13 matches the speed state of the continuously variable transmission 10 corresponding to the operation position is obtained.
[0054]
[Another embodiment]
FIG. 10 shows a traveling operation device according to another embodiment. This operation device has a lower end connected to an upper portion of the support body 41 and an upper end side slidably supported by a tip lever portion 13e. It includes a release rod 44 and a gripping member 13f connected to the upper end side of the lock release rod 44 and slidably supported by the distal end lever portion 13e. That is, the gripping member 13f is pushed down along the distal end lever portion 13e to push down the lock release rod 44. Then, the locking release rod 44 operates to lower the support 41 against the locking spring 37, thereby releasing the locking body 34 from the positioning recesses 35 and 36. Therefore, when the shift lever 13 is rocked while the gripping member 13f is pressed down, the locking body 34 comes out of the positioning recesses 35, 36 due to the cam action of the inclined inner surfaces on the front and rear sides of the positioning recesses 35, 36. Speed change operation without resistance.
[0055]
In the above embodiment, the positioning recesses 35 and 36 are formed such that the angles formed by the inclined inner surfaces on the front and rear sides of the positioning recesses 35 and 36 and the depth of the positioning recesses 35 and 36 are the same at any operation position. However, as shown in FIG. 9, the angle of the inclined inner surfaces 35a and 36a and the depth of the positioning recesses 35 and 36 become steeper or deeper toward the high-speed side, and the positioning recesses 35 and 36 are deepened. It may be configured and supported such that the stronger the locking lever is exerted to the higher speed side, the stronger the locking lever is exerted and the position is firmly held. Further, the positioning recesses 35 and 36 are formed so that the angles of the inclined inner surfaces on the front and rear sides of the positioning recesses 35 and 36 are different, and when the shift lever 13 is moved, the locking body 34 is moved from the positioning recesses 35 and 36. The operation resistance generated by the disengagement is different depending on whether the shift lever 13 is moved to the speed increasing side or to the speed decreasing side, so that the shift operation can be performed while easily recognizing the shifting direction. May be implemented.
[0056]
The present invention can be applied to a work vehicle provided with a crawler belt instead of the wheels 1 and 2. Therefore, the wheels 1 and 2, the crawler belt, and the like are collectively referred to as traveling devices 1 and 2.
[Brief description of the drawings]
FIG. 1 is a side view of an entire agricultural tractor. FIG. 2 is a side view of a traveling operation device. FIG. 3 is a side view of an operation unit of a continuously variable transmission. FIG. 4 is a cross-sectional view of an operation unit of a continuously variable transmission. 5 is a side view of the position holding means. FIG. 6 is a cross-sectional view of the position holding means. FIG. 7 is a cross-sectional view of a tip side portion of the speed change lever. FIG. 8 is an explanatory view of an operation position. FIG. FIG. 10 is a side view of a positioning recess. FIG. 10 is a side view of an operating device having another embodiment.
1, 2 Traveling device 10 Continuously variable transmission 10a Operating portion 13 Transmission lever 16a Oscillating shaft core 30 of transmission lever Locking type position holding means 32a Oscillating shaft core 33 of positioning member Positioning member 34 Locking members 35, 36 Positioning Concave portion 50 Friction-type position holding means 51 Friction member 53 Long hole 54 Support shaft

Claims (4)

A traveling shift operation device for a working vehicle in which an operation portion of a continuously variable transmission that transmits power to the traveling device is linked with a manually operated shift lever.
Frictionless position holding means acting on the shift lever to hold the shift lever in the operating position by friction when the continuously variable transmission is in either the low speed range or the high speed range; and And only when in the high speed range of the high speed range, locking type position holding means acting on the shift lever to hold the shift lever in the operating position by entry of the locking body into the positioning recess,
The shift lever is swingably supported, and the locking body is attached to the shift lever so as to move with respect to the shift lever in a direction intersecting the swing axis of the shift lever. The positioning member provided is swingably supported around an axis parallel to the swing axis of the shift lever,
A long hole elongated in a moving direction of a speed change lever provided on the positioning member, a support shaft attached to the speed change lever so as to be movably inserted through the long hole, and a positioning member; A traveling speed change operation device for a working vehicle , comprising: a friction member supported by the support shaft in a state of being pressed against the traveling shaft . The traveling speed change operation device for a working vehicle according to claim 1, wherein the continuously variable transmission is a hydrostatic continuously variable transmission. The friction-type position holding means acts on the shift lever when the continuously variable transmission is in the low-speed range and the high-speed range on both sides of the forward and backward movements. 3. The traveling speed change operation device for a working vehicle according to claim 2, wherein the device operates on the speed change lever when the vehicle is in a high speed range on both sides of the traveling direction. The traveling speed change operation device for a working vehicle according to any one of claims 1 to 3, wherein the elongated hole is formed in an arc shape as viewed in a direction along a pivot axis of the speed change lever.

Images