Work vehicles

Abstract

Some ride-on work machines are equipped with a stop switch to prevent the engine from overheating. However, suddenly stopping the engine by operating the stop switch also stops the engine's cooling system, which is counterproductive and can lead to malfunction. Therefore, we provide a work vehicle that appropriately prevents overheating and subsequent inability to move. [Solution] In a work vehicle equipped with a work machine 4 on a vehicle body 2 which is equipped with a transmission 23 that changes the driving force of the engine 20, a sensor is provided to detect overheating of the engine 20, and an overheating warning is issued when the sensor detects overheating.

Description

Technical Field

[0001] The present invention relates to work vehicles such as riding type rice transplanters, combines, tractors, etc.

Background Art

[0002] There is a riding type work machine provided with a stop switch for preventing the engine from overheating (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, if the engine is suddenly stopped by operating the stop switch, the cooling of the engine also stops, which has the opposite effect and leads to failure.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a work vehicle that appropriately prevents overheating and becoming unable to travel.

Means for Solving the Problems

[0006] The invention according to claim 1 is a work vehicle equipped with a work implement 4 on a traveling vehicle body 2 provided with a transmission 23 for changing the driving force of an engine 20, provided with a sensor 55 for detecting overheating of the engine 20, and performing an overheating warning by the overheating detection of the sensor 55.

[0007] According to the invention described in claim 1, the operator can immediately recognize the overheating of the engine 20 with an overheat warning, and can appropriately prevent the vehicle from becoming inoperable due to overheating by reducing the load on the engine 20 by decelerating the transmission 23 by a predetermined amount.

[0008] The invention described in claim 2 is the work vehicle according to claim 1, wherein a warning display prompting deceleration is shown on the display device 37a.

[0009] The invention described in claim 3 is a work vehicle equipped with a work machine 4 on a vehicle body 2 which is provided with a transmission 23 that changes the driving force of an engine 20, and is provided with a sensor 55 that detects overheating of the engine 20, and the transmission 23 is decelerated when the sensor 55 detects overheating.

[0010] According to the invention described in claim 3, by decelerating the transmission 23 upon detection of overheating by the sensor 55, the load on the engine 20 can be reduced, thereby effectively preventing the vehicle from becoming inoperable due to overheating.

[0011] The invention described in claim 4 is a work vehicle according to claim 3, wherein the deceleration of the transmission 23 is reduced by a predetermined amount compared to the shift operation position of the shift lever 33.

[0012] The invention described in claim 5 is a work vehicle according to claim 3 or 4, wherein when the gear lever 33 is returned to neutral, the automatic deceleration control is canceled and the gear transmission 23 is returned to neutral.

[0013] The invention described in claim 6 is a work vehicle according to claim 5, wherein when the gear shift lever 33 is returned to the neutral position, the automatic reduction amount is corrected so that as the gear shift lever 33 is operated toward the deceleration side, the reduction amount approaches the reduction amount corresponding to the operating position. [Brief explanation of the drawing]

[0014] [Figure 1] This is a side view of a riding-type rice transplanter according to an embodiment of the present invention. [Figure 2]It is a front view of the engine. [Figure 3] It is a plan view of the operation panel. [Figure 4] It is a correction table of the deceleration amount.

Embodiments for Carrying out the Invention

[0015] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0016] <Overall Configuration> FIG. 1 is a side view of a riding type rice transplanter, which is an example of a riding type working machine of the present invention.

[0017] In the riding type rice transplanter 1, a seedling planting part 4 as a working machine is mounted so as to be able to move up and down via a lifting link device 3 on the rear side of a traveling vehicle body 2, and a main body part of a fertilizer applicator 5 is provided on the upper rear part of the traveling vehicle body 2.

[0018] On both left and right sides of the front part of the traveling vehicle body 2, left and right spare seedling carriers 7, 7 that can be rotationally switched between a working state where the base is projected outward of the machine body and a storage state where it is stored inward of the machine body and left and right line markers 8, 8 that can be rotationally switched between a working state where the base is projected outward of the machine body and a storage state where it is stored inward of the machine body are provided on the upper part of a support frame 6 whose base is fixed to the machine body.

[0019] Note that the left and right directions are referred to as left and right respectively when facing the forward direction of the riding type seedling transplanter, and the forward and backward directions are referred to as front and back respectively.

[0020] <Traveling Vehicle Body 2> The traveling vehicle body 2 is a four-wheel drive vehicle equipped with a pair of left and right front wheels 10, 10 as drive wheels and a pair of left and right rear wheels 11, 11. A transmission case 12 is arranged at the front part of the machine body, and front wheel final cases 13, 13 are provided on the left and right sides of the transmission case 12. The left and right front wheels 10, 10 are respectively attached to left and right front wheel axles that protrude outward from respective front wheel support parts capable of changing the steering direction of the left and right front wheel final cases 13, 13.

[0021] Also, the front end of the main frame 15 is fixed to the rear part of the mission case 12, and the rear wheel gear cases 18, 18 are supported so as to be rotatable about a rear wheel rolling shaft provided horizontally in the front-rear direction at the left and right center of the rear end of the main frame 15. Rear wheels 11, 11 are attached to the rear wheel axles protruding outward from the rear wheel gear cases 18, 18.

[0022] The engine 20 is mounted on the main frame 15, and the rotational power of the engine 20 is transmitted to the mission case 12 via a belt transmission device and an HST 23 as a transmission device. The rotational power transmitted to the mission case 12 is shifted by a transmission in the case 12 and then separated into traveling power and external extraction power and extracted. Then, part of the traveling power is transmitted to the front wheel final cases 13, 13 to drive the front wheels 10, 10, and the rest is transmitted to the rear wheel gear cases 18, 18 to drive the rear wheels 11, 11. Also, the external extraction power is transmitted to a planting clutch case provided at the rear of the traveling vehicle body 2, and then transmitted to the seedling planting part 4 by a planting transmission shaft 26 and transmitted to the fertilizer applicator 5 by a fertilizer transmission mechanism.

[0023] The upper part of the engine 20 is covered with an engine cover 30, and a seat 31 is installed thereon.

[0024] There is a front cover 32 incorporating various operation mechanisms in front of the seat 31, an HST lever 33 as a shift lever for operating the HST 23 on the side thereof, a handle 34 for steering operation of the front wheels 10, 10 above it, a monitor 37a as a display device on the operation panel 37 on the upper surface, and a control device 38 provided inside.

[0025] The HST lever 33 has a neutral position in the middle of the front-rear operation. The forward speed increases as it is operated forward from the neutral position, and the reverse speed increases as it is operated backward from the neutral position.

[0026] Specifically, a potentiometer for detecting the operating position is provided near the HST lever 33. The operating position detection value of the HST lever 33 detected by the potentiometer is input to the control device 38, and the control device 38 operates the electric motor based on the operating position detection value to operate the trunnion shaft of the HST 23 to perform neutral, forward acceleration / deceleration, and reverse acceleration / deceleration corresponding to the operating position of the HST lever 33.

[0027] The lower left and right ends of the engine cover 30 and front cover 32 are horizontal floor steps 35. Part of the floor steps 35 are latticed so that mud from the shoes of workers walking on the steps 35 falls onto the field. The rear of the floor steps 35 is a rear step 36 which also serves as a rear wheel fender.

[0028] The lifting link device 3 has a parallel link configuration and includes an upper link 40 and a lower link 41.

[0029] The upper link 40 and the lower link 41 are rotatably attached to a rear-view gate-shaped link base frame 42, which is erected at the rear end of the main frame 15, by a front upper pivot axis 40a and a front lower pivot axis 41a, respectively. A vertical link 43 is rotatably connected to the front end of the upper link 40 and the rear lower pivot axis 41b.

[0030] Then, a connecting shaft 44, which is rotatably supported by the seedling planting section 4, is inserted and connected to the lower end of the vertical link 43, and the seedling planting section 4 is connected so as to be able to roll around the connecting shaft 44.

[0031] A lifting hydraulic cylinder 46 is provided between the link base frame 42 and the vertical link 43. By extending and retracting the lifting hydraulic cylinder 46 with a hydraulic valve, the lifting link device 3 rotates up and down, causing the seedling planting section 4 to move up and down while maintaining a nearly constant position.

[0032] Here, we will explain the means to prevent the engine 20 from overheating and rendering the aircraft unable to fly.

[0033] Figure 2 shows a front view of the engine 20, and Figure 3 shows a top view of the control panel 37.

[0034] The engine 20 is a multi-cylinder engine mounted horizontally on the main frame 15, with the cylinder head and head cover mounted on the upper part of the engine body 50, the oil pan mounted on the lower part, the gear case and radiator 51 mounted on the right side, and the flywheel 52 and muffler 53 mounted on the left side, which is a typical configuration.

[0035] In particular, a thermostat 55, which acts as a sensor for detecting the temperature of the engine 20, is fixed to the engine body 50 by bolting together with a coolant discharge pipe 57 that connects to the radiator 51 at the coolant discharge port 54 from the engine body 50 to the radiator 51 using bolts 56.

[0036] The control device 38 performs the following control based on the temperature detected by the engine 20, which is sent from the thermostat 55.

[0037] In other words, if the temperature detected by the thermostat 55 for the engine 20 is above a predetermined temperature indicating overheating, the control device 38 displays a warning on the monitor 37a of the operation panel 37, stating "Overheat! Move the HST lever to the deceleration position by a predetermined amount," to prompt the operator to decelerate. The deceleration indication may be, for example, two steps of deceleration as shown on the monitor 37a in Figure 3.

[0038] Therefore, the operator can immediately recognize the engine 20 overheating from the warning display on monitor 37a, and by operating the HST lever 33 to a predetermined deceleration position, reduce the load on the engine 20 and appropriately prevent the vehicle from becoming inoperable due to overheating.

[0039] In another embodiment, if the engine 20 overheats, the HST 23 is automatically decelerated to reduce the load on the engine 20 and appropriately prevent the vehicle from becoming inoperable due to overheating.

[0040] In other words, if the temperature detected by the thermostat 55 for the engine 20 is above a predetermined temperature indicating overheating, the control device 38 activates the electric motor to operate the trunnion shaft of the HST 23, reducing its speed by a predetermined amount from the operating position of the HST lever 33 (for example, reducing it by two steps as shown on the monitor 37a in Figure 3).

[0041] Simultaneously with the automatic deceleration, the monitor 37a on the control panel 37 displays "HST decelerating due to overheating."

[0042] Furthermore, the control device 38 activates the electric accelerator in response to the deceleration of the HST23, thereby reducing the rotational speed of the engine 20.

[0043] Then, after automatically decelerating the HST23 and returning the HST lever 33 to the neutral position, the potentiometer detects that the HST lever 33 has been operated to the neutral position. The control device 38, upon receiving the detection of the neutral position from the potentiometer, cancels the automatic deceleration control and activates the electric motor to operate the trunnion shaft of the HST23 to neutralize the HST23.

[0044] As shown in the table in Figure 4, when the HST lever 33 is returned to the neutral position after the HST 23 is automatically decelerated, the HST lever 33 is operated to the deceleration side and returns to the neutral position. Therefore, as the HST lever 33 is operated to the deceleration side, the operating position of the automatically decelerated trunnion shaft is corrected to approach the operating position of the trunnion shaft of the HST 23 operated by the electric motor, which corresponds to the operating position of the HST lever 33 detected by the potentiometer.

[0045] Furthermore, when the control device 38 detects overheating of the engine 20, it activates the electric accelerator by setting the HST lever 33 to the neutral position for a predetermined time (for example, 20 seconds) to bring the engine speed to an idling state.

[0046] Therefore, the cooling effect of the coolant in the radiator 51 and the function of the cooling fan can lower the temperature of the heat dissipation part and prevent damage to the engine 20.

[0047] When the HST lever 33 is operated from the neutral position to the forward or reverse side, the control device 38 checks the operating position of the HST lever 33 at predetermined intervals by detecting it with a potentiometer, and gradually restores the engine speed to the normal operating state according to the amount of change in operation.

[0048] On the other hand, as another example of an engine 20 overheat detection method, instead of the thermostat 55, the overheat may be detected by a sensor that detects the rise in the coolant level in the radiator 51's reserve tank.

[0049] In other words, when the engine overheats, the pressure valve of the radiator 51 remains open, causing the liquid level in the reserve tank to rise. This rise is detected by a sensor, which then detects the overheating.

[0050] Furthermore, to prevent malfunctions during coolant replenishment, the above sensor will only detect overheating when the engine is running.

[0051] The above sensors are installed in pairs on separate sides of the reserve tank, a predetermined distance (e.g., 100 mm) above the reference water level. Overheating is detected when both sensors are in contact with the liquid simultaneously for a predetermined number of seconds (e.g., 5 seconds).

[0052] Furthermore, as another example of an engine 20 overheat detection method, an engine load sensor is provided on the engine 20, and data is calculated in advance that the engine load sensor will continuously detect the maximum load, which will render the vehicle inoperable, and stored as a specified engine load value. The control device 38 determines that the vehicle is overheating when the engine load sensor continuously detects the maximum load and exceeds the specified engine load value.

[0053] Furthermore, as another example of an overheat detection means for the engine 20, an overheat switch is provided, and the control device 38 determines that the engine is overheating when the overheat switch exceeds a reference value.

[0054] On the other hand, after the engine 20 is stopped, the cooling water circulation and cooling fan are controlled to continue operating for a predetermined number of seconds (for example, 30 seconds), regardless of the engine temperature.

[0055] <Seedling planting section 4> The seedling planting unit 4 has a 6-row configuration and includes a transmission case 70 that also serves as a frame, a seedling platform 71 on which a mat of seedlings is placed and moves back and forth to supply one seedling at a time to the seedling outlet 71a of each row, and a seedling feed belt that transports the seedlings downward to supply all the seedlings in a horizontal row to the seedling outlet 71a, and a seedling planting device 72 that plants the seedlings supplied to the seedling outlet 71a into the field.

[0056] The lower part of the seedling planting section 4 is equipped with a center float 75 in the middle and side floats 76, 76 on either side. When the machine is moved with these floats 75, 76, 76 in contact with the mud surface of the field, the floats 75, 76, 76 glide along while leveling the mud surface, and seedlings are planted in the leveled areas by the seedling planting device 72.

[0057] Each float 75, 76, and 76 is rotatably mounted so that its front end moves up and down in accordance with the unevenness of the topsoil surface of the field. During planting, the vertical movement of the front of the center float 75 is detected by the angle of attack control sensor, and the hydraulic valve that controls the lifting hydraulic cylinder 46 is switched according to the detection result to raise and lower the seedling planting unit 4, thereby maintaining a constant planting depth for the seedlings.

[0058] The seedling planting section 4 is equipped with a soil leveling rotor 27, which is an example of a soil leveling device.

[0059] <Fertilizer 5> The fertilizer applicator 5 dispenses granular fertilizer stored in the fertilizer hopper 80 in fixed amounts via the dispensing unit 81, guides the fertilizer via the fertilizer hose 82 to the fertilizer guides 83 attached to both the left and right sides of the floats 75, 76, 76, and drops it into the fertilizer area formed near the side of the seedling planting row by the furrowing body 84 located in front of the fertilizer guides 83.

[0060] Air generated by a blower, driven by an electric motor for the blower, is blown into the fertilizer hose 82 via a long air chamber 85 in the left-right direction, and the fertilizer inside the fertilizer hose 82 is forcibly transported by air pressure. [Explanation of Symbols]

[0061] 2. Running vehicle 4 Work equipment (seedling planting section) 20 Engine 23. Transmission (HST) 33. Gear shift lever (HST lever) 37a Display device (monitor) 55 Sensor (Thermostat)

Claims

1. A work vehicle equipped with a work machine (4) on a vehicle body (2) which has a transmission (23) that changes the driving force of an engine (20), characterized in that a sensor (55) for detecting engine (20) overheating is provided, and an overheating warning is issued when the sensor (55) detects overheating.

2. The work vehicle according to claim 1, characterized in that a warning display prompting deceleration is shown on the display device (37a).

3. A work vehicle equipped with a work machine (4) on a vehicle body (2) which has a transmission (23) that changes the driving force of an engine (20), characterized in that a sensor (55) is provided to detect overheating of the engine (20), and the transmission (23) is decelerated when the sensor (55) detects overheating.

4. The work vehicle according to claim 3, characterized in that the deceleration of the transmission (23) is a predetermined amount less than the shift operation position of the shift lever (33).

5. The work vehicle according to claim 3 or 4, characterized in that when the gear shift lever (33) is returned to neutral, the automatic deceleration control is canceled and the gear shift device (23) is returned to neutral.

6. The work vehicle according to claim 5, characterized in that when the gear shift lever (33) is returned to the neutral position, the automatic reduction amount is corrected so that as the gear shift lever (33) is operated toward the deceleration side, the reduction amount approaches the reduction amount corresponding to the operating position.

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