JPH072449B2 - Shift structure of work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a traveling transmission that is operated by an actuator so that a shift position corresponding to an operation position of a shift operation lever is provided, and a traveling clutch is turned on and off. A clutch sensor for detecting the state is provided, and when the clutch sensor detects the disengaged state of the traveling clutch, the traveling transmission is switched to a predetermined low speed position and the operation position of the shift operation lever is detected based on the clutch operation detection. In the speed change structure of the work vehicle, which is provided with a control device for returning to the original speed change position, when the travel clutch is operated during seedling replenishment, etc., the travel speed change device is temporarily operated regardless of the operation position of the shift operation lever. It relates to the speed change structure of a work vehicle typified by rice transplanters, etc., which adopts a control that does not suddenly start the next time the vehicle is started at the lowest speed. .

[Conventional technology]

Conventionally, in this type of work vehicle gear shifting structure, as shown in FIG. 4, a single limit switch (S) is provided so as to detect when the clutch pedal (13) is depressed and completely switched to the disengaged state. ₃ ) had been placed.

[Problems to be Solved by the Invention]

In this case, when the limit switch senses the clutch pedal, the traveling transmission automatically shifts to a predetermined low speed position. Since the traveling transmission returns to the original shift position before the state is completely returned to, the higher the shift position, the greater the shock caused by sudden start.

An object of the present invention is to provide a speed change structure for a work vehicle that does not suddenly start even in a half-clutch state.

[Means for Solving the Problems]

A characteristic configuration according to the present invention is that, while the clutch sensor detects a half-clutch state, it prevents complete switching to the original shift position, and at the time of switching to a complete on-state, The control device controls to return to the original gear position or to start the return operation. The action and effect are as follows.

[Action]

As the clutch sensor, as shown in FIG. 3, a limit switch as the clutch sensor (S) is provided at a position where the clutch (12) is completely disengaged and a position where the clutch (12) is completely engaged, or A tachometer such as potentiometer or encoder will be used.

Therefore, when the clutch (12) is completely disengaged, the transmission (5) is moved to a predetermined low speed position (actually the lowest speed position).
When the clutch is switched to the half-clutch state while returning from the disengaged state to the disengaged state, the original shift position is not restored.

Therefore, in the half-clutch state, the predetermined low speed position is maintained, or the shift operation is performed such that the half-clutch state is closer to the shift position as the half-clutch state is closer to the on-state. To switch to.

Then, either of the method of switching to the original shift position at the time when the clutch is completely switched to the on state or starting the shift toward the original shift position is adopted.

〔The invention's effect〕

As a result, it is possible to prevent the return to the original shift position in the half-clutch state by making a simple change to the clutch sensor, so that it is possible to suppress a shift shock due to a sudden start as compared with the conventional case.

[Embodiment] As shown in FIG. 7, an engine (4) is provided at the front part of a traveling vehicle body (3) equipped with front and rear wheels (1) and (2), and a belt type as the traveling transmission and the engine (4). A transmission case (6) transmission-coupled through a continuously variable transmission (5), a control section (7) provided in the middle of the machine body, and a drive cylinder (32) driven behind the control section (7). A working machine equipped with a seedling planting device (9) that is vertically movable through an elevator link mechanism (8) and wire drawing markers (10) located on both sides of the seedling planting device (9). As an example, a riding type rice transplanter is configured. Incidentally, (34) in FIG.
Is a cylinder for rolling the seedling planting device (9) with respect to the lifting link mechanism (8).

As shown in FIG. 1, the belt type continuously variable transmission (5) uses split pulleys (5a) and (5b) as input pulleys on the transmission case (6) side, and the split pulleys (5a) and (5b )
By moving one (5a) with respect to the other (5b) in the perspective direction by the electric actuator (11), the wrapping angle of the belt can be changed to continuously change the speed. A main clutch (12) is provided for the output shaft of the engine (4), and the main clutch (12) is turned on and off by a foot pedal (13).
Further, as shown in FIG. 2, a main speed change lever (14) is provided at the foot of the operation portion (7), and the first forward speed used during planting traveling and the second forward speed used during road traveling. , And 1st reverse speed can be switched to 3 speeds. Therefore, the number of stages of the continuously variable transmission (5) is superimposed at each shift position.

Further, below the seedling planting device (9), there is provided a grounding sensor (15) which moves up and down due to fluctuations in grounding pressure.
The display panel of the operation section (7) is provided with an encoder-type plowing depth setting device (16). In order to maintain the set value of this plowing depth setting device (16), the detection result of the ground sensor (15) is displayed. Based on this, a raising / lowering control device for raising and lowering the seedling planting device (9) to maintain a constant planting depth is provided.

In addition to the plowing depth setting device (16), as shown in FIG. 2, the operation lever (17) for the continuously variable transmission (5), the seedling supply switch (18) [this The seedling supply switch is a switch positioned at an optimum height for seedling support (19) seedling replenishment, and the transmission shaft (21) input from the traveling vehicle body to the feed case (20) of the seedling planting device (9). ) Is parallel to the ground, and is positioned at a height that does not interfere with the ground even if the planting claws (22) rotate. It is a seedling scraping test and a fertilizer application test (not shown). It is located at a height where it is possible to do so. ], A fuel lamp (23), an accelerator lever (24), a planting lever (25), a marker switch (26) for inserting / removing a drawing marker (10), and a fail display lamp (28). The fuel lamp (23) is turned off when the seedling supply switch is set and when another sensor / actuator or the like has an abnormality, and is turned on when the various sensors / actuators are normal.

Next, the relationship between the main clutch (12) that also serves as the traveling clutch and the continuously variable transmission (5) will be described. As shown in FIG. 3, limit switches (S ₁ ) and (S ₂ ) are provided as clutch sensors (S) at the maximum depressed position and the maximum returned position of the clutch pedal (13) for the main clutch (12), respectively. is there. When it is detected that the clutch pedal (13) is stepped on and the limit switch (S ₁ ) reaches the maximum stepped position, the actuator (11) operates the continuously variable transmission (5) to a predetermined deceleration position. Switch to the lowest deceleration position (LOW).

The continuously variable transmission (5) maintains the lowest deceleration position (LOW) even if the clutch is switched from the state to the half-clutch state in the process of returning to the clutch-engaged state.

When the limit switch (S ₂ ) detects that the clutch (12) has been completely switched to the on state (maximum return position), the continuously variable transmission (5) returns to the original gear position. . Therefore, there is no sudden start. However, the operation position of the continuously variable transmission operation lever (17) serving as the shift operation lever is maintained at a position corresponding to the original shift position. Also, the main clutch (12) is often disengaged during seedling replenishment, and the clutch pedal (1
Stop the rice transplanter with 3) locked and replenish the seedlings.

Based on the above configuration, a mode in which the vehicle speed is controlled by the traveling load will be described based on the flowchart of FIG. When the engine is started, the control is not started unless the operating lever (17) for the continuously variable transmission is once set to the lowest speed position (LOW). Therefore, first, it is confirmed whether the operation lever (17) for the continuously variable transmission is once operated to the lowest speed position (LOW). Then, once operated, check the ON-OFF state of the main clutch (12) and
5) Check whether the position is the “planting position” or the “up position” of the seedling planting device is “neutral position” or “down position”. When it is not operated to the lowest speed position (LOW), or when the main clutch (12) is disengaged, or when the planting lever (25) is in the "up position", "neutral position" or "down" of the seedling planting device. If it is in the "position", the shift target value (OBPBUF) in the software for the continuously variable transmission (5) is set to the lowest speed position (LOW), and the current operating position of the continuously variable transmission (5) ( PRERO)
Is in the lowest speed position (LOW), the lowest speed position (LOW)
To the actuator (11).

In other words, in other words, when the engine (4) is started, the main clutch (12) is in the engaged state, and the operation lever (17) for the continuously variable transmission is not yet operated to the lowest speed position (OBP), it is the lowest. The rice transplanter will start once if the speed is maintained.
Then, when the driver notices it and once switches the operation lever (17) for the continuously variable transmission to the lowest speed position (LOW) and further to the desired shift position, the main routine control such as speed control is started. However, even if the operation lever (17) for the continuously variable transmission is once moved to the lowest speed position (LOW), if the main clutch (12) is in the disengaged or half-clutch state, it is determined that the seedling is being replenished and the lowest speed is obtained. Keep it in the position (LOW),
When the planting lever (25) is raised, it is judged that it is turning on the edge of the ridge and is turned slowly at the lowest speed position (LOW). In any of these cases, the setting is made independently of the shift instruction position (OBP) as the operation position of the continuously variable transmission operation lever (17).

Here, the position of the planting lever (25) is to be determined only when the main speed change lever (14) is set in the gear shift range corresponding to the planting position, that is, when planting work is performed.

When the operation lever (17) for the continuously variable transmission is once operated to the lowest speed position (LOW) and the main clutch (12) is in the engaged state, although not shown in the flow chart, the starting form is as described above. A method of rapidly shifting to the shift instruction position (OBP) of the operation lever (17) of the continuously variable transmission (5) or gently shifting to the shift instruction position (OBP) or a predetermined deceleration value is adopted. When the main shift lever (14) is operated to the planting position, the planting work is in progress,
Looking at the position of the planting lever (25), when the planting lever (25) is in the "up position", it is determined that the vehicle is turning on the ridge, and the continuously variable transmission (5) is moved to the lowest speed position ( LOW), rotate slowly, and when the planting lever (25) is in the "planting position", the planting lever (25) rapidly moves to the shift instruction position (OBP) of the operation lever (17) for continuously variable transmission. A method of shifting or gradually shifting to the shift instruction position (OBP) or a predetermined deceleration value is adopted. When the seedling lever (25) is in the "neutral position" and the "lower position", it is assumed that seedlings are being supplied, and the continuously variable transmission (5) is set to the lowest speed position (LOW).
To

As described above, depending on the gear position of the main gear shift lever (14), it is determined whether the planting operation is being performed or the vehicle is traveling on the road, and the process proceeds to the next vehicle speed control (step I).

Next, vehicle speed control will be described in which the actuator (11) is controlled to automatically shift gears regardless of the shift instruction position (OBP) of the continuously variable transmission operation lever (17) depending on the engine load. The vehicle speed control mode and the artificial vehicle speed control mode in which the vehicle speed is set based on the operation of the operation lever (17) for the continuously variable transmission are determined by whether the accelerator lever (24) is in the full accelerator position. , The vehicle speed control mode is set at the full accelerator position. However, another dedicated changeover switch may be provided so that the accelerator position can be arbitrarily selected. In vehicle speed control mode, the engine speed (ER) is 2000 rpm
If it is between ˜3000 rpm, the shift position is appropriate, so that state is maintained. If it is 2,000 rpm or less, it is determined that the load is large and the gear shift operation is performed to the lowest speed position (LOW) (step II).

Next, when the accelerator lever (24) is in a position other than the full accelerator position, and when the engine speed (ER) is 3000rp
If it exceeds m, shift target value in software (OBPBUF)
To the shift instruction position (OBP) by the operation lever (17) for the continuously variable transmission, thereby artificially controlling the speed by artificially operating the operation lever (17) for the continuously variable transmission. (Step II
I).

In the artificial vehicle speed control mode described above, the drive duty for the electric actuator (11) is made larger than the drive duty for the vehicle speed control mode to increase the operating speed of the actuator (11). Thus, the control device (27) with a built-in microcomputer that controls the artificial vehicle speed control mode and the vehicle speed control mode is provided.

[Other Embodiments] The actuator (11) may be a hydraulic type and is not limited to an electric type.

A tachometer such as a potentiometer or an encoder may be used as the clutch sensor (S).

As the traveling transmission, the main transmission in the mission (6) and the belt continuously variable transmission (5) are used, but either one may be used. A gear type transmission may be used instead of the belt continuously variable transmission (5).

The traveling clutch may be provided separately from the main clutch (12).

When the clutch (12) is in a half-clutch state, it may gradually return from the lowest speed position (LOW) to the original shift position.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a control configuration diagram, FIG. 2 is a plan view showing a control section, FIG. 3 is a side view showing a clutch sensor mounting structure, and FIG. 4 is a side view showing a conventional clutch sensor mounting structure. 5
FIG. 6 is a configuration diagram showing another embodiment relating to signal processing from the clutch sensor, FIG. 6 is a control flow chart, and FIG. 7 is a side view showing a riding type rice transplanter. (5) …… Traveling transmission, (11) …… Actuator,
(12) …… Running clutch, (17) …… Shift operation lever, (27) …… Control device, (S) …… Clutch sensor.

Claims (1)

[Claims] 1. A travel transmission (5) is provided which is operated to change gears by an actuator (11) so that a shift position corresponding to an operation position of a shift operation lever (17) is provided, and a travel clutch (12) is turned on and off. A clutch sensor (S) for detecting the state is provided, and when the clutch sensor (S) detects the disengaged state of the traveling clutch (12), the traveling transmission (5) is switched to a predetermined low speed position and a clutch engagement operation is detected. A shift structure for a work vehicle provided with a control device (27) for returning to the original shift position corresponding to the operation position of the shift operation lever (17) based on While the clutch state is being detected, complete switching to the original shift position is prevented, and at the time of switching to the complete engagement state, the original shift position is restored or a return operation is performed. Transmission structure of the working vehicle controlled by the control device to initiate (27).