JP4989501B2 - Working gear shifting structure - Google Patents

Description

  The present invention relates to a traveling speed change structure for a work vehicle that operates in association with a traveling speed change device and a governor device that controls the fuel injection amount of an engine.

  In a work vehicle, as disclosed in Patent Document 1, a transmission for traveling (FIG. 3 in Patent Document 1 and 41 in FIG. 14), a governor device for controlling the fuel injection amount of the engine (Patent Document 1). 95 of FIG. 10, a shift lever that can be operated artificially (FIG. 3 of Patent Document 1 and 53 of FIG. 10), and an accelerator pedal that can be manually operated (30 of FIG. 10 of Patent Document 1). In some cases, the transmission lever and the traveling transmission and governor device are mechanically linked, and the accelerator pedal and the governor device are mechanically linked.

  As a result, when the shift lever is operated to the high speed side (low speed side), the traveling transmission device is operated to the high speed side (low speed side), and at the same time, the governor device is operated to the high speed side (low speed side). When the accelerator pedal is depressed (returned), the governor device is operated on the high speed side (low speed side). In this case, the governor device is configured to be operated based on the operation position on the high speed side of the operation position of the shift lever and the operation position of the accelerator pedal.

  In Patent Document 1, since the traveling transmission device and the governor device can be operated by the transmission lever, the driver performs the transmission operation by operating the transmission lever without stepping on the accelerator pedal. By operating the speed change lever to a desired position, the aircraft can be driven at a constant travel speed (the speed change position of the speed change transmission and the position of the governor device corresponding to the operation position of the speed change lever). it can.

  If you want to temporarily accelerate while the aircraft is traveling at a constant travel speed, you can operate the shift lever by operating the shift lever by depressing the accelerator pedal to the high speed side beyond the shift lever operation position. It is possible to perform temporary acceleration by operating at a higher speed than the position corresponding to the position and increasing the engine speed (the traveling transmission device remains in the shift position corresponding to the operation position of the shift lever). Have been). Next, when the accelerator pedal is returned to the low speed side beyond the operation position of the shift lever, the governor device is returned to the position corresponding to the operation position of the shift lever.

JP 2006-204143 A

In Patent Document 1, a state in which the aircraft is traveling at a constant traveling speed is the main one, and for the driver, the operation subject is a shift lever, and when the vehicle is temporarily accelerated, the accelerator pedal is used. It has become.
Thus, in Patent Document 1, when the traveling transmission device is operated to the low speed side by the shift lever in order to travel at a low speed, the governor device is also operated to the low speed side accordingly. Etc., engine output may be insufficient. In such a state, there is room for improvement in terms of operability because it is necessary to secure the engine speed (output) by depressing the accelerator pedal and simultaneously operating the speed change lever to the low speed side.

In recent years, when an operation lever and an operation pedal for operating a transmission for traveling and a governor device are provided, a work vehicle using an operation subject as an operation pedal for a driver has been proposed.
The present invention has the advantage of Patent Document 1 (the governor device and the traveling transmission device together on the high speed side and the low speed side) when an operation lever and an operation pedal for operating the traveling transmission device and the governor device are provided in the work vehicle. It is intended to be configured so that an appropriate operation can be performed by an operation pedal.

[I]
(Constitution)
A first feature of the present invention resides in the following structure in a traveling speed change structure for a work vehicle.
A maneuverable manipulator that can be operated manually, a gearbox for shifting by adjusting the position of the swash plate, a gearshift mechanism for operating the gearbox for driving, and an injection amount adjusting device for controlling the fuel injection amount of the engine. And an operation pedal that can be stepped on artificially, and the injection amount adjusting device is configured to be operated based on the operation position of the operation lever and the operation position of the operation pedal.
Of the engine speed corresponding to the operation position of the operation pedal and the engine speed corresponding to the operation position of the operation lever, the fuel injection amount adjustment is performed so that the fuel injection amount corresponds to the high-speed operation position. Controlling the device, the position of the swash plate, the position of the swash plate corresponding to the actual engine speed, and the position of the swash plate corresponding to the operation position of the operation pedal Control means for controlling the position so as to be closer to the position of the swash plate is provided.

(Function)
According to the first feature of the present invention, when the work vehicle includes an operation lever and an operation pedal for operating the traveling transmission and the injection amount adjusting device, based on the operation position of the operation lever and the operation position of the operation pedal. The injection amount adjusting device is operated.
According to the first feature of the present invention, when the operation lever is operated at an arbitrary operation position and the operation position of the operation pedal is lower than the operation position of the operation lever (the engine corresponding to the operation position of the operation pedal). the speed, if it is the low speed side than the rotational speed of the engine corresponding to the operation position of the operating lever), in a state where the injection amount adjusting device is operated at a position corresponding to the position of the operating lever, the operating pedal The traveling transmission can be operated.

According to the first feature of the present invention, the operating lever is operated to an arbitrary operating position, and the operating position of the operating pedal is at a lower speed side than the operating position of the operating lever (the engine rotation corresponding to the operating position of the operating pedal). In the state where the number is lower than the engine speed corresponding to the operating position of the operating lever), even if the traveling transmission is operated to the lower speed side by the operating pedal, it corresponds to the operating position of the operating lever. Since the injection amount adjusting device is operated (maintained) at the position and the engine speed (output) is ensured, traveling at low speed can be performed without any problem.
In this case, as in Patent Document 1 (see [Problems to be Solved by the Invention]), the speed lever is operated to the low speed side, and at the same time, the accelerator pedal is operated to secure the engine speed (output). There is no need to perform such operations.

According to the first feature of the present invention, the operation position of the operation pedal is higher than the operation position of the operation lever in a state where the operation lever is operated to an arbitrary operation position (corresponding to the operation position of the operation pedal). When the engine speed is higher than the engine speed corresponding to the operating position of the operating lever), the injection amount adjusting device and the traveling transmission can be operated together by the operating pedal to the higher speed side. It is possible to operate the injection amount adjusting device and the traveling transmission device together with the operation pedal to the low speed side.
As a result, the advantage of Patent Document 1 (the injection amount adjusting device and the traveling transmission can be operated together on the high speed side and the low speed side) remains as it is.

(Effect of the invention)
According to the first aspect of the present invention, when the operating vehicle includes an operation lever and an operation pedal for operating the traveling transmission device and the injection amount adjusting device, the injection amount adjusting device and the traveling transmission device are connected together by the operation pedal. In addition, while maintaining the advantages of being able to operate on the high speed side and low speed side, it is possible to run at low speeds with the operating pedal without any trouble by ensuring the engine speed (output) and improving the running performance of the work vehicle I was able to.

[II]
(Constitution)
The second feature of the present invention resides in the following structure in the traveling speed change structure for a work vehicle according to the first feature of the present invention.
A brake for traveling and a brake pedal that can be operated on the brake side and that can be manually operated are provided. When the brake pedal is depressed operated, so control transmission for traveling in preference to control means is operated to stop position, a third control means for operating the transmission mechanism.

(Function)
According to the second feature of the present invention, the “action” described in the preceding item [I] is provided in the same manner as the first feature of the present invention, and in addition to this, the following “action” is provided.
According to the second feature of the present invention, when the brake pedal is depressed when the airframe is being stopped, the travel transmission is operated toward the stop position, so that the travel transmission is at a high speed. In such a state that the brake is operated to the braking side in a state where the power is transmitted to the side, the state is not generated.

(Effect of the invention)
According to the second feature of the present invention, the “effect of the invention” described in the preceding item [I] is provided in the same manner as the first feature of the present invention. In addition, the following “effect of the invention” is provided. ing.
According to the second feature of the present invention, when the aircraft is stopped, the brake is operated to the braking side while the traveling transmission is operated to the high speed side and the power is transmitted. The state can be avoided, the state where an excessive load is applied to the brake can be avoided, and the durability of the brake and the stopping performance of the work vehicle can be improved.

[III]
(Constitution)
A third feature of the present invention resides in the following structure in the traveling speed change structure for a work vehicle according to the second feature of the present invention.
After the being the brake pedal depression operation is the aircraft has stopped, when the operation pedal is not depressed operated, braking as transmission for traveling in preference to control means is operated in a very low speed position, the speed change mechanism operating And fourth control means.

(Function)
According to the third feature of the present invention, the “action” described in the preceding item [I] [II] is provided in the same manner as the first or second feature of the present invention. In addition, the following “action” is provided. It has.
According to the third feature of the present invention, after the brake pedal is stepped on and the airframe is stopped, when the brake pedal is returned and operated without the operation pedal being stepped on, the airframe starts at a slow speed and the slow speed is reached. The aircraft will stop moving when the brake pedal is depressed. Thereby, for example, a state like creep in a general passenger car can be obtained, and when it is desired to slightly change the position of the aircraft, the position of the aircraft can be easily and accurately changed.

(Effect of the invention)
According to the third feature of the present invention, the “effect of the invention” described in the preceding paragraphs [I] and [II] is provided in the same manner as the first or second feature of the present invention. The effect of the invention is provided.
According to the third feature of the present invention, the position of the airframe can be easily and accurately changed, and the operability of the work vehicle can be improved.

[1]
As shown in FIG. 1, an engine 3 and a transmission case 4 are provided on an airframe supported by right and left front wheels 1 and right and left rear wheels 2 that can be steered left and right, and an operation unit 5 is provided. Thus, an agricultural tractor that is an example of a work vehicle is configured.

  As shown in FIGS. 1 and 2, the motive power of the engine 3 is a hydrostatic continuously variable transmission 6 (corresponding to a transmission for traveling) provided in a transmission case 4 and a gear transmission-type auxiliary transmission. (Not shown) is transmitted to the front wheel 1 and the rear wheel 2. The continuously variable transmission 6 is configured to be freely operated in a stop position N, a forward region F, and a reverse region R, and a swash plate of the continuously variable transmission 6 by an actuator 7 (corresponding to a transmission mechanism) operated by the control device 10. (Not shown) is operated, and the continuously variable transmission 6 is changed.

  As shown in FIGS. 1 and 2, a steering handle 8 for steering the front wheel 1 is provided at the top of the front portion of the driving unit 5, and a forward / reverse lever 9 is provided on the left side of the steering handle 8. The forward / reverse lever 9 is configured to be freely operated at a forward position F and a reverse position R, and an operation position of the forward / backward lever 9 is input to the control device 10. An operation lever 11 on the right side of the steering handle 8 is provided. The operation lever 11 is configured to be operable in the range of the lowest speed position L1 and the highest speed position H1 and to be held at an arbitrary operation position. The operating position of the lever 11 is input to the control device 10.

  As shown in FIGS. 1 and 2, an operation pedal 12 is provided at the lower right side of the front portion of the driving unit 5, and the operation pedal 12 can be stepped in the range of the lowest speed position L <b> 2 and the highest speed position H <b> 2. The operation position of the operation pedal 12 is input to the control device 10. A shift lever 14 is provided on the right side of the driver's seat 13 provided in the driver 5, and the shift lever 14 can be operated in the range of the stop position N and the maximum speed position F2 and can be held at an arbitrary operation position. The operation position of the shift lever 14 is input to the control device 10.

  As shown in FIG. 2, a governor device 15 (mechanically operated or electronically controlled) that controls the fuel injection amount of the engine 3 is provided, and the governor device 15 is operated by the control device 10. A rotation speed sensor 16 for detecting the actual rotation speed N2 of the engine 3 is provided, and a detection value of the rotation speed sensor 16 is input to the control device 10.

[2]
As shown in FIG. 2, the work mode and the road mode are set in the control device 10, and the driver selects the work mode and the road mode by operating the selection switch 19 provided in the driving unit 5. Next, the work mode will be described with reference to FIGS.
In the work mode, the swash plate and the governor device 15 of the continuously variable transmission 6 are operated as follows based on the operation position of the operation lever 11, the operation position of the operation pedal 12, and the operation position of the transmission lever 14.

  The operation position of the operation lever 11 is detected (step S1), the operation position of the operation pedal 12 is detected (step S2), and the operation position of the operation lever 11 and the operation position of the operation pedal 12 are compared (step S3). ). When the operation position of the operation lever 11 is higher than the operation position of the operation pedal 12 (step S3), a set rotational speed N1 corresponding to the operation position of the operation lever 11 is set (step S4). When the operation position is higher than the operation position of the operation lever 11 (step S3), the set rotational speed N1 corresponding to the operation position of the operation pedal 12 is set (step S5).

  In this case, the highest speed position H1 of the operating lever 11 corresponds to the highest speed position H2 of the operating pedal 12, and the lowest speed position L1 of the operating lever 11 corresponds to the lowest speed position L2 of the operating pedal 12. The set rotation speed N1 corresponding to the highest speed positions H1 and H2 of the operation lever 11 and the operation pedal 12 corresponds to the highest rotation speed of the engine 3 and corresponds to the lowest speed positions L1 and L2 of the operation lever 11 and the operation pedal 12. The set rotational speed N1 corresponds to the idling rotational speed of the engine 3.

  In the work mode, in general, the operation lever 11 is often operated in the range of the lowest speed position L1 and the highest speed position H1 in a state where the operation lever 12 is positioned at the lowest speed position L2 without being stepped on. In the state, the set rotation speed N1 corresponding to the operation position of the operation lever 11 is set (step S4). If it is desired to temporarily accelerate, when the operation pedal 12 is stepped on to the maximum speed position H2 beyond the operation position of the operation lever 11, a set rotation speed N1 corresponding to the operation position of the operation pedal 12 is set (step S5). When the operation pedal 12 is moved back to the minimum speed position L2 beyond the operation position of the operation lever 11, a set rotational speed N1 corresponding to the operation position of the operation lever 11 is set (step S4).

  The actual number of revolutions N2 of the engine 3 is detected (step S6), and the governor device 7 is operated by the control device 10 so that the actual number of revolutions N2 of the engine 3 becomes the set number of revolutions N1. The engine speed N2 of the engine 3 is maintained at the set speed N1 (step S7).

The operation position of the shift lever 14 is detected (step S8), and the operation position of the forward / reverse lever 9 is detected (step S9). When the forward / reverse lever 9 is operated to the forward movement position F, the actuator 7 is operated by the control device 10 in the forward movement area F, and the swash plate of the continuously variable transmission 9 is moved to the transmission position corresponding to the operation position of the transmission lever 14. Is operated (step S10). When the forward / reverse lever 9 is operated to the reverse position R, the actuator 7 is operated by the control device 10 in the reverse region R, and the swash plate of the continuously variable transmission 9 is set to the speed change position corresponding to the operation position of the speed change lever 14. Is operated (step S11).
In this case, the stop position N of the transmission lever 14 corresponds to the stop position N of the swash plate of the continuously variable transmission 9, and the highest speed position F2 of the transmission lever 14 is the most forward (reverse) of the continuously variable transmission 9. Corresponds to the high-speed position M.

[3]
Next, the road mode will be described with reference to FIGS.
In the road mode, the swash plate and the governor device 15 of the continuously variable transmission 6 are operated based on the operation position of the operation lever 11 and the operation position of the operation pedal 12 as follows. The position is ignored.

  The operation position of the operation lever 11 is detected (step S21), the operation position of the operation pedal 12 is detected (step S22), and the operation position of the operation lever 11 and the operation position of the operation pedal 12 are compared (step S23). ). If the operation position of the operation lever 11 is higher than the operation position of the operation pedal 12, the control device 10 operates the governor device 15 at a position corresponding to the operation position of the operation lever 11 (step S24). If the operating position is higher than the operating position of the operating lever 11, the control device 10 operates the governor device 15 to a position corresponding to the operating position of the operating pedal 12 (step S25).

  In this case, the highest speed position H1 of the operating lever 11 corresponds to the highest speed position H2 of the operating pedal 12, and the lowest speed position L1 of the operating lever 11 corresponds to the lowest speed position L2 of the operating pedal 12. If the traveling load or work load is not applied to the engine 3, the rotational speed corresponding to the position of the governor device 15 and the actual rotational speed N2 of the engine 3 are substantially the same. 3, the actual rotational speed N2 of the engine 3 is slightly lower than the rotational speed corresponding to the position of the governor device 15.

  As shown in FIG. 6, the relationship line A1 (dashed line) between the position of the swash plate of the continuously variable transmission 6 and the actual rotational speed N2 of the engine 3, and the position of the swash plate of the continuously variable transmission 6 and the operation pedal A relation line A2 (solid line) with 12 operation positions is set. In this case, the relationship line A1 is set closer to the stop position N than the relationship line A2, except for the vicinity of the idling speed of the engine 3 (near the lowest speed position L2 of the operation pedal 12).

  The actual rotational speed N2 of the engine 3 is detected (step S26). Based on the relationship line A1 (actual rotational speed N2 of the engine 3) based on the actual rotational speed N2 of the engine 3, the inclination of the continuously variable transmission 6 is corrected. The position of the plate is calculated (step S27). Based on the operation position of the operation pedal 12 (step S22), the position of the swash plate of the continuously variable transmission 6 is calculated based on the relationship line A2 (operation pedal 12) (step S28), and the relationship line A1 (actual engine 3). Is compared with the position of the swash plate of the continuously variable transmission 6 based on the relationship line A2 (operation pedal 12) (step S29).

  As a result, the position of the swash plate of the continuously variable transmission 6 based on the relationship line A1 (actual speed N2 of the engine 3) is changed to the position of the swash plate of the continuously variable transmission 6 based on the relationship line A2 (operation pedal 12). If it is closer to the stop position N (step S29), if the forward / reverse lever 9 is operated to the forward position F (step S30), the actuator 7 is operated by the control device 10 in the forward region F, so that it is continuously variable. The swash plate of the transmission 9 is operated to the position of the swash plate of the continuously variable transmission 6 based on the relationship line A1 (actual engine speed N2) (step S32). If the forward / reverse lever 9 is operated to the reverse position R (step S30), the actuator 7 is operated by the control device 10 in the reverse region R, and the swash plate of the continuously variable transmission 9 is related to the relationship line A1 (actual engine A1). 3 is operated to the position of the swash plate of the continuously variable transmission 6 based on the rotational speed N2) (step S33).

  The position of the swash plate of the continuously variable transmission 6 based on the relationship line A2 (operating pedal 12) stops more than the position of the swash plate of the continuously variable transmission 6 based on the relationship line A1 (actual speed N2 of the engine 3). If it is on the position N side (step S29), if the forward / reverse lever 9 is operated to the forward position F (step S31), the actuator 7 is operated by the control device 10 in the forward region F, and the continuously variable transmission 9 Is operated to the position of the swash plate of the continuously variable transmission 6 based on the relationship line A2 (operation pedal 12) (step S34). If the forward / reverse lever 9 is operated to the reverse position R (step S31), the actuator 7 is operated by the control device 10 in the reverse region R, and the swash plate of the continuously variable transmission 9 is connected to the relationship line A2 (operation pedal 12). ) Is operated to the position of the swash plate of the continuously variable transmission 6 based on (step S35).

[4]
In other words, the steps S29 to S35 in the road mode described in [3] are based on the scope of claims (Claim 1).
For example, when the operation lever 12 is operated to an intermediate position between the lowest speed position L1 and the highest speed position H1, and the operation pedal 12 is stepped on the lower speed side than the operation position of the operation lever 11 is operated. (Corresponding to a state in which the rotational speed of the engine 3 corresponding to the operating position of the operating pedal 12 is lower than the rotational speed of the engine 3 corresponding to the operating position of the operating lever 11). The governor device 15 is operated at a position corresponding to the 11 operation position, and the actual rotational speed N2 of the engine 3 becomes the rotational speed corresponding to the position of the governor apparatus 15. In this case, when a traveling load or a work load is applied to the engine 3, the actual rotational speed N <b> 2 of the engine 3 is slightly lower than the rotational speed corresponding to the position of the governor device 15.

As described above, the position of the swash plate of the continuously variable transmission 6 based on the relationship line A2 (the operation pedal 12) is usually obtained when the operation pedal 12 is stepped on the lower speed side than the operation position of the operation lever 11. Is on the stop position N side of the position of the swash plate of the continuously variable transmission 6 based on the relationship line A1 (actual speed N2 of the engine 3), so that the continuously variable transmission is performed in steps S29, S31, S34, and S35. The swash plate of the device 9 is operated to the position of the swash plate of the continuously variable transmission 6 based on the relation line A2 (operation pedal 12) (the transmission 6 for traveling is at a shift position corresponding to the operation position of the operation pedal 12). as it will be operated, corresponding to a state where the speed change mechanism 7 is operated) (control means).

In this case, in a state where the operation pedal 12 is stepped on the lower speed side than the operation position of the operation lever 11, the operation pedal 12 is stepped on the speed side slightly lower than the operation position of the operation lever 11, In a state in which a large traveling load or work load is applied to the engine 3 and the actual rotational speed N2 of the engine 3 is larger than the rotational speed corresponding to the position of the governor device 15, the relationship line A1 (actual The position of the swash plate of the continuously variable transmission 6 based on the rotational speed N2) of the engine 3 is closer to the stop position N than the position of the swash plate of the continuously variable transmission 6 based on the relationship line A2 (operation pedal 12). There is.
In such a state, the swash plate of the continuously variable transmission 9 is related by steps S29, S30, S32, and S33 in a state where the operation pedal 12 is stepped on the lower speed side than the operation position of the operation lever 11. The position of the swash plate of the continuously variable transmission 6 is operated based on the line A1 (actual speed N2 of the engine 3).

  For example, when the operation lever 12 is operated to the high speed side with respect to the operation position of the operation lever 11 in a state where the operation lever 11 is operated to an intermediate position between the lowest speed position L1 and the highest speed position H1. (Corresponding to a state in which the rotational speed of the engine 3 corresponding to the operating position of the operating pedal 12 is higher than the rotational speed of the engine 3 corresponding to the operating position of the operating lever 11). The governor device 15 is operated at a position corresponding to the 12 operation positions, and the actual rotational speed N2 of the engine 3 becomes the rotational speed corresponding to the position of the governor apparatus 15. In this case, when a traveling load or a work load is applied to the engine 3, the actual rotational speed N <b> 2 of the engine 3 is slightly lower than the rotational speed corresponding to the position of the governor device 15.

  As described above, in a state where the operation pedal 12 is operated at a higher speed than the operation position of the operation lever 11, the continuously variable transmission 6 based on the relationship line A1 (actual engine speed N2) is usually used. Since the position of the swash plate is closer to the stop position N than the position of the swash plate of the continuously variable transmission 6 based on the relationship line A2 (operation pedal 12), the continuously variable transmission is performed in steps S29, S30, S32, and S33. Nine swash plates are operated to the position of the swash plate of the continuously variable transmission 6 based on the relationship line A1 (actual speed N2 of the engine 3).

In this case, if the operation pedal 12 is stepped on to the maximum speed position H2 side, the governor device 15 is operated to a position corresponding to the operation position of the operation pedal 12, and the actual rotational speed N2 of the engine 3 becomes the high speed side. Therefore, the swash plate of the continuously variable transmission 9 is operated to the position of the swash plate of the continuously variable transmission 6 based on the relationship line A1 (the actual rotational speed N2 of the engine 3). Is operated to the highest speed position M side of forward (reverse) (the transmission mechanism 7 is operated so that the traveling transmission 6 is operated to the transmission position corresponding to the operation position of the operation pedal 12). or equivalent) (control means).

[5]
Next, the stop operation of the aircraft in the road mode will be described.
As shown in FIG. 2, a right side brake 17 (corresponding to a traveling brake) capable of braking the right rear wheel 2 and a left side brake 17 (corresponding to a traveling brake) capable of braking the left rear wheel 2 are provided. Equivalent). Right and left side brake pedals 18 (corresponding to brake pedals) are provided at the lower right side of the front part of the driving unit 5 so that they can be operated independently, and the right side brake 17 and the right side brake pedal 18 are The left side brake 17 and the left side brake pedal 18 are mechanically linked via the linkage mechanism 20 via the linkage mechanism 20.

As shown in FIG. 2, the right (left) side brake pedal 18 is configured to be stepped in the range of the release position B1 and the limit position B2, and is biased to the release position B1, and the right (left) side brake pedal 18 is The operation position of the side brake pedal 18 is input to the control device 10.
As shown by the relationship line C1 (dashed line) in FIG. 7, the setting position B3 is set from the intermediate position between the release position B1 and the limit position B2 to the release position B1 side, and the right (left) side brake When the pedal 18 starts to be depressed from the release position B1 (the release state of the right (left) side brake 17), the right (left) side brake 17 is in the release state between the release position B1 and the set position B3. Thus, the linkage mechanism 20 is configured (so-called “play” of the linkage mechanism 20). When the right (left) side brake pedal 18 is stepped over the set position B3, the right (left) side brake 17 starts to be operated from the released state to the braking side, and the right (left) side brake pedal 18 is operated. The linkage mechanism 20 is configured so that the right (left) side brake 17 is in the maximum braking state when the pedal is operated to the limit position B2.

When stopping the aircraft, both the right and left side brake pedals 18 are stepped on simultaneously. In this case, the actuator 7 is operated by the control device 10 and the swash plate of the continuously variable transmission 9 is operated, as indicated by a relation line C2 (solid line) in FIG.
Actually, even if both the right and left side brake pedals 18 are stepped on simultaneously, the operating positions of both the right and left side brake pedals 18 are always the same due to variations in the way of stepping. For example, when both the right and left side brake pedals 18 are stepped on at the same time in a state where the right side brake pedal 18 is slightly closer to the release position B1 than the left side brake pedal 18, for example. There are many. Accordingly, the swash plate of the continuously variable transmission 9 is operated as described below based on the operation position of the side brake pedal 18 on the release position B1 side of the right and left side brake pedals 18.

  As shown in FIGS. 5 and 7, for example, when the swash plate of the continuously variable transmission 6 is operated to the highest speed position M for forward (reverse), both the right and left side brake pedals 18 are simultaneously released. When the stepping operation is started from B1 (step S41), the operation positions of the right and left side brake pedals 18 are compared (step S42). If the operation position of the left side brake pedal 18 is closer to the release position B1 than the operation position of the right side brake pedal 18, the operation position of the left side brake pedal 18 is set as the low operation position B (step S43). ) When the operation position of the right side brake pedal 18 is closer to the release position B1 than the operation position of the left side brake pedal 18, the operation position of the right side brake pedal 18 is set as the low operation position B. (Step S44).

  As shown in FIGS. 5 and 7, when the low-side operation position B is between the release position B1 and the setting position B3 (step S45), the continuously variable transmission is performed based on the low-side operation position B and the relation line C2. The swash plate of the apparatus 6 is operated from the highest speed position M of forward movement (reverse movement) to the stop position N side (step S46) (third control means). In this case, based on the operation position of the right side brake pedal 18, the right side brake 17 is operated (or not operated) to the braking side as shown by the relation line C1, and the left side brake pedal 18 is not operated. Based on the operation position, the left side brake 17 is operated to the braking side (or not operated) as shown by the relationship line C1.

  As shown in FIGS. 5 and 7, when the low-side operation position B is between the set position B3 and the limit position B2 (step S45), the relationship line C1 is based on the operation position of the right side brake pedal 18. As shown in FIG. 4, the right side brake 17 is operated (or not operated) to the braking side, and based on the operation position of the left side brake pedal 18, the left side brake 17 is moved to the braking side as shown by the relationship line C1. It is operated (or not operated), and the swash plate of the continuously variable transmission 6 is operated to the forward (reverse) fine speed position M1 (step S47) (third control means).

  The position of the swash plate of the continuously variable transmission 6 at the forward (reverse) slow speed position M1 is set to about several percent of the position of the swash plate of the continuously variable transmission 6 at the highest speed (M) of forward movement (reverse). Yes. In this case, since the braking force of the right and left side brakes 17 sufficiently overcomes the driving force of the continuously variable transmission 6 at the forward (reverse) slow speed position M1, the airframe stops without any problem. (Third control means).

When performing the stop operation of the machine body, after releasing the foot from the operation pedal 12, both the right and left side brake pedals 18 are stepped on simultaneously from the release position B1 to the limit position B2. In this case, whether or not the swash plate of the continuously variable transmission 6 is operated to the stop position N side as the operating pedal 12 is returned to the lowest speed position L2 (see [4] in the previous section). Alternatively, at a higher speed, the swash plate of the continuously variable transmission 6 is operated to the stop position N (the slow speed position M1 of the previous term (reverse)) as described above.
When stopping the aircraft, if both the right and left side brake pedals 18 and the operation pedal 12 are operated by mistake at the same time, the operation position of the operation pedal 12 is ignored and the continuously variable transmission is performed as described above. The swash plate of the device 6 is operated to the stop position N (preceding (reverse) slow speed position M1) side.

As described above, when performing a small turn, such as when turning on the heel, for the state where both the right and left side brake pedals 18 are stepped on simultaneously to stop the aircraft. Only one of the right and left side brake pedals 18 may be depressed.
When only one of the right and left side brake pedals 18 is stepped on in this way, the operation position of the side brake pedal 18 that is not stepped on becomes the release position B1 side and is set as the low side operation position B (step) S42, S43). Since the low-side operation position B is the release position B1, the swash plate of the continuously variable transmission 6 is not operated to the stop position N side but is maintained as it is. Thereby, a small turn can be performed without hindrance.

[6]
Next, the start operation of the aircraft in the road mode after performing the stop operation of the aircraft described in [5] above will be described with reference to FIG.
As described in [5] above, when both the right and left side brake pedals 18 are depressed simultaneously, the right and left side brakes 17 are operated to the braking side, and the swash plate of the continuously variable transmission 6 moves forward. It is operated to the slow speed position M1 (reverse) (step S47), and the aircraft stops. Even after the airframe stops (step S48), the swash plate of the continuously variable transmission 6 moves forward (reverse) as long as the operation pedal 12 is not depressed (as long as it is operated to the lowest speed position L2) (step S51). It is operated (maintained) at the slow speed position M1 (step S50) (fourth control means).

In the aforementioned state, when the right and left side brake pedals 18 are operated to return to the release position B1, the swash plate of the continuously variable transmission 6 is operated to the forward (reverse) fine speed position M1 (step). S50), the aircraft starts at a slow speed and starts to move forward (reverse) at a slow speed.
In this case, after the aircraft stops (step S48), the operation position of the operation lever 11 is detected (step S49), and the closer the operation position of the operation lever 11 is to the highest speed position H1, the more forward (reverse) the operation is. The slow speed position M1 is set slightly on the low speed side (position close to the stop position N), and the closer the operation position of the operating lever 11 is to the lowest speed position L1, the forward (reverse) slow speed position M1 is set slightly faster. (Step S50).

  When the operation pedal 12 is operated to the lowest speed position L2, the governor device 15 is operated to a position corresponding to the operation position of the operation lever 11 by the control device 10 (steps S23 and S24). Thereby, when the operation position of the operation lever 11 is close to the lowest speed position L1, if the forward (reverse) fine speed position M1 is too close to the stop position N, the forward speed (reverse speed) at the low speed is too slow. Therefore, when the operation position of the control lever 11 is close to the lowest speed position L1, the forward (reverse) fine speed position M1 is set slightly higher, and the forward speed (reverse speed) at an appropriate fine speed is set. Speed) is obtained (steps S49 and S50).

  On the contrary, when the operation position of the control lever 11 is far from the lowest speed position L1, if the forward (reverse) fine speed position M1 is too far from the stop position N, the forward speed (reverse speed) at the fine speed is too fast. Therefore, when the operation position of the control lever 11 is far from the lowest speed position L1, the forward (reverse) fine speed position M1 is set slightly on the low speed side, and the forward speed (reverse speed) at an appropriate fine speed is set. Speed) is obtained (steps S49 and S50).

  Next, when the operation pedal 12 is started to be depressed, the process proceeds to step S21. Initially, the position corresponding to the operation position of the operation lever 11 as in the previous section [3] [4] and steps S23, S24, S26 to S35. In the state where the governor device 15 is operated (step S24), the swash plate of the continuously variable transmission 9 is operated to the position of the swash plate of the continuously variable transmission 6 based on the relation line A2 (operation pedal 12) (high speed). Side operated).

  When the operation pedal 12 is further depressed, the operation position of the operation pedal 12 becomes higher than the operation position of the operation lever 11 (the rotation speed of the engine 3 corresponding to the operation position of the operation pedal 12 is In step S23 and S25, the governor device 15 is operated to a position corresponding to the operation position of the operation pedal 12, and the actual engine is reached. 3 is the rotational speed corresponding to the position of the governor device 15, and the swash plate of the continuously variable transmission 6 moves forward (reverse) at the highest speed position M side as described in [3] and [4] above. To be operated.

[First Alternative Embodiment of the Invention]
Instead of [3] [4] of [Best Mode for Carrying Out the Invention] and Steps S26 to S35 of FIG. 4, the following configuration may be used.
The operation position of the operation lever 11 is detected (step S21), the operation position of the operation pedal 12 is detected (step S22), and the operation position of the operation lever 11 and the operation position of the operation pedal 12 are compared (step S23). ).
In this case, if the operation position of the operation lever 11 is higher than the operation position of the operation pedal 12, the control device 10 operates the governor device 15 to a position corresponding to the operation position of the operation lever 11 (step S24). The control device 10 and the actuator 7 operate the swash plate of the continuously variable transmission 6 to a shift position corresponding to the operation position of the operation pedal 12.
When the operation position of the operation pedal 12 is higher than the operation position of the operation lever 11, the control device 10 operates the governor device 15 at a position corresponding to the operation position of the operation pedal 12 (step S25). The actuator 7 operates the swash plate of the continuously variable transmission 6 to a shift position corresponding to the operation position of the operation pedal 12.

[Second Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention] [First Alternative Embodiment], the swash plate of the continuously variable transmission 6 is operated to the stop position N in step S47 of FIG. In S48, S49, and S50, the swash plate of the continuously variable transmission 6 may be operated to the very low speed position M1.

[Third Another Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention] [First Alternative Embodiment] [Second Alternative Embodiment], instead of the hydrostatic continuously variable transmission 6, a belt type is used. Alternatively, a continuously variable transmission (not shown) of another type may be used, or a stepped transmission (not shown) such as a gear transmission may be used.

Whole side view of agricultural tractor The figure which shows the linkage state of an operation lever and an operation pedal, a continuously variable transmission, a governor apparatus, a brake, and a brake pedal Diagram showing control flow of work mode Diagram showing the flow of road mode control The figure which shows the flow of control of the stop and start operation of the body in the road mode The figure which shows the relationship between the operation position of an operation pedal, the actual engine speed, and the position of the swash plate of a continuously variable transmission. The figure which shows the relationship between the operation position (low side operation position) of the right (left) side brake pedal, the position of the swash plate of the continuously variable transmission, and the right (left) side brake

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Engine 6 Traveling transmission 7 Transmission mechanism 11 Operation lever 12 Operation pedal 15 Governor device 17 Brake 18 Brake pedal N Stop position of traveling transmission M1 Fine speed position of traveling transmission

Claims (3)

Artificial operation, a transmission for traveling that changes speed by adjusting the position of the swash plate, a transmission mechanism that operates the transmission for transmission, an injection amount adjustment device that controls the fuel injection amount of the engine, and Equipped with an operation lever that can be operated and an operation pedal that can be stepped on artificially,
The injection amount adjusting device is configured to be operated based on the operation position of the operation lever and the operation position of the operation pedal,
Of the engine speed corresponding to the operation position of the operation pedal and the engine speed corresponding to the operation position of the operation lever, the fuel injection amount adjustment is performed so that the fuel injection amount corresponds to the high-speed operation position. Control the device,
The position of the swash plate is set to the position of the swash plate in a stopped state among the position of the swash plate corresponding to the actual engine speed and the position of the swash plate corresponding to the operation position of the operation pedal. A traveling speed change structure for a work vehicle, comprising control means for controlling the position to be closer . A brake for traveling, and a brake pedal that can be operated artificially by operating the brake on the braking side,
When the brake pedal is depressed operated, as before Symbol system transmission for traveling in preference to control means is operated to stop position, claims are provided with a third control means for operating said speed change mechanism Item 2. A traveling speed change structure for a work vehicle according to Item 1. Wherein the brake pedal is depressed operation after the aircraft has stopped, so that when the operation pedal is not being depressed operation, the previous SL system transmission for traveling in preference to control means are operated to fine speed position, The traveling speed change structure for a work vehicle according to claim 2, further comprising fourth control means for operating the speed change mechanism.

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