JP7571106B2 - Snowplow and method for controlling snowplow - Google Patents

Description

The present invention relates to a snowplow and a method for controlling the snowplow.

Conventionally, there has been known a control device for a transmission in a snowplow that can prevent mechanical damage to the auger, blower, engine, etc. caused by abnormal torque without using a shear pin (see, for example, Patent Document 1).

When a difference occurs between the measurements of the input shaft rotation sensor, which measures the rotation speed of the transmission's input shaft, and the output shaft rotation sensor, which measures the rotation speed of the transmission's output shaft, this snowplow disengages the clutch from the gear. This prevents mechanical damage to the auger, blower, engine, etc., caused by abnormal torque.

JP 2015-25323 A

However, in the snowplow described in Patent Document 1, when the clutch is disengaged from the gear, the auger and blower stop simultaneously, and the collected snow tends to accumulate inside the vehicle body. This causes the problem that the accumulated snow needs to be removed before work can be resumed.

In order to solve the above problems, a snowplow according to one aspect of the present invention is a snowplow in which rotational power from a prime mover is input via a power transmission path to an auger that rakes up snow and a blower that discharges the snow rake up by the auger, and which comprises a first clutch that is located on the power transmission path and can be switched between a connected state in which the power from the prime mover is transmitted downstream in the power transmission direction and a disconnected state in which the power from the prime mover is not transmitted downstream in the power transmission direction, and a second clutch that is located on the power transmission path downstream of the first clutch and divides the power from the first clutch into auger drive power and blower drive power, and the auger drive power is a power divider that branches the power transmission path into an auger drive power transmission path for transmitting the auger drive power and a blower drive power transmission path for transmitting the blower drive power; a second clutch that is located on the auger drive power transmission path and is switchable between a connected state in which the auger drive power is transmitted downstream in a power transmission direction and a disconnected state in which the auger drive power is not transmitted downstream in the power transmission direction; a first clutch actuator that switches between the connected state and the disconnected state of the first clutch; a second clutch actuator that switches between the connected state and the disconnected state of the second clutch; a first sensor, a second sensor for detecting a rotation speed of a first rotating mechanical element that transmits power from the first clutch toward the second clutch or power from the power divider toward the blower, a third sensor for detecting a rotation speed of a second rotating mechanical element that transmits power from the second clutch toward the auger, and a controller for controlling the first clutch actuator and the second clutch actuator, the controller detecting a rotation speed of the first rotating mechanical element when the first clutch and the second clutch are in the connected state, the first rotation speed corresponding to the rotation speed of the prime mover detected by the first sensor, When a first slippage, which is the difference between a first reference rotation speed, which is the rotation speed of the mechanical element, and the rotation speed of the first rotating mechanical element detected by the second sensor, exceeds a predetermined threshold value, the first clutch is switched to the disengaged state, and when a second slippage, which is the difference between a second reference rotation speed, which is the rotation speed of the second rotating mechanical element corresponding to the rotation speed of the prime mover detected by the first sensor, and the rotation speed of the second rotating mechanical element detected by the third sensor, when the first clutch and the second clutch are in the engaged state, exceeds a predetermined threshold value, the second clutch is switched to the disengaged state.

In order to solve the above problems, a control method for a snowplow according to one aspect of the present invention is a control method for a snowplow in which rotational power from a prime mover is input via a power transmission path to an auger that rakes up snow and a blower that discharges the snow rake up by the auger, and the snowplow includes a first clutch that is located on the power transmission path and is switchable between a connected state in which the power from the prime mover is transmitted downstream in the power transmission direction and a disconnected state in which the power from the prime mover is not transmitted downstream in the power transmission direction, and a front clutch that is located on the power transmission path downstream of the first clutch and is switchable between a connected state in which the power from the prime mover is transmitted downstream in the power transmission direction and a disconnected state in which the power from the prime mover is not transmitted downstream in the power transmission direction. a power divider that divides power from the first clutch into auger drive power and blower drive power and branches the power transmission path into an auger drive power transmission path that transmits the auger drive power and a blower drive power transmission path that transmits the blower drive power; a second clutch that is located on the auger drive power transmission path and is switchable between a connected state in which the auger drive power is transmitted downstream in a power transmission direction and a disconnected state in which the auger drive power is not transmitted downstream in a power transmission direction; a first rotating mechanical element which transmits power from the power divider toward the blower, and a second rotating mechanical element which transmits power from the second clutch toward the auger, the rotation speeds of the prime mover, the first rotating mechanical element, and the second rotating mechanical element are detected, a first reference rotation speed is calculated, which is the rotation speed of the first rotating mechanical element when the first clutch and the second clutch are in the connected state and corresponds to the detected rotation speed of the prime mover, and a relationship between the first reference rotation speed and the detected rotation speed of the first rotating mechanical element is calculated. A first slippage, which is the difference, is calculated, and when the first slippage exceeds a predetermined threshold, the first clutch is switched to the disengaged state; a second reference rotation speed, which is the rotation speed of the second rotating machine element when the first clutch and the second clutch are in the engaged state and corresponds to the detected rotation speed of the prime mover, is calculated, and a second slippage, which is the difference between the second reference rotation speed and the detected rotation speed of the second rotating machine element, is calculated, and when the second slippage exceeds a predetermined threshold, the second clutch is switched to the disengaged state.

The present invention can keep the blower operating when the second clutch is disconnected and the auger is stopped. This has the effect of preventing snow from accumulating and allowing snow removal work to be resumed quickly. In addition, the first sensor can be used in common as an input sensor used to calculate the first slippage amount and the second slippage amount, which has the effect of simplifying the configuration for detecting the rotation speed of the input shaft of the torque limiter and the input shaft of the second clutch.

1 is a side view showing an example of the configuration of a snowplow according to an embodiment. FIG. 2 is a plan view showing a configuration example of the snowplow shown in FIG. 1 . 2 is a plan view showing a schematic configuration example of a power transmission mechanism of the snowplow shown in FIG. 1 . FIG. 2 is a cross-sectional view showing an example of the configuration of a torque limiter of the snowplow shown in FIG. 1 . 2 is a block diagram showing an example of the configuration of a control system of the snowplow shown in FIG. 1; 4 is a flowchart showing an example of operation of the snowplow of FIG. 1, and is a flowchart showing disengagement control of a first clutch. 4 is a flowchart showing an example of operation of the snowplow of FIG. 1, and is a flowchart showing disengagement control of the second clutch. 4 is a flowchart showing an example of an operation of the snowplow of FIG. 1 , and is a flowchart showing a return control.

The following describes the embodiments with reference to the drawings. Note that the present invention is not limited to the following embodiments. In addition, the same or corresponding elements are denoted by the same reference symbols throughout the drawings, and duplicate descriptions are omitted.

The functions of the elements disclosed herein can be performed using circuits or processing circuits, including general purpose processors, special purpose processors, integrated circuits, ASICs (Application Specific Integrated Circuits), conventional circuits, and combinations of the above elements, configured or programmed to perform the disclosed functions. Processors are considered processing circuits or circuits because they include transistors and other circuits. In this disclosure, a circuit, unit, or means is hardware that performs the recited functions or hardware that is programmed to perform the recited functions. The hardware may be hardware disclosed herein or other known hardware that is programmed or configured to perform the recited functions. When the hardware is a processor, which is considered a type of circuit, the circuit, means, or unit is a combination of hardware and software, and the software is used in at least one configuration of the hardware and the processor.

Figure 1 is a side view showing an example of the configuration of a snowplow 100 according to an embodiment. Figure 2 is a plan view showing an example of the configuration of the snowplow 100. Figure 3 is a plan view showing a schematic example of the configuration of the power transmission mechanism 3 of the snowplow 100 in Figure 1. In the following description, the concept of direction is that the forward movement direction of the snowplow 100 is the front, the backward movement direction of the snowplow 100 is the rear, and the lateral direction of the vehicle perpendicular to the front-rear direction is the left-right direction or vehicle width direction. In the following, the number of rotations per unit time is simply referred to as the rotation speed.

The snowplow 100 is a rotary snowplow, a vehicle that travels while removing snow that has accumulated on the road surface. As shown in FIG. 1, the snowplow 100 includes a prime mover E, a vehicle body 1, wheels W that support the vehicle body 1, a rotary device 2 provided on the front side of the vehicle body 1, and a power transmission mechanism 3 shown in FIG. 3.

The prime mover E is an internal combustion engine. The prime mover E may be an electric motor or a combination of an internal combustion engine and an electric motor. The prime mover E is controlled by the ECM 5, which is an engine control module shown in FIG. 3. The ECM 5 is an electric circuit, and has, for example, a processor with a computing unit such as a CPU, and memories such as ROM and RAM.

The vehicle body 1 includes an engine room 10 and a driver's room 11. A motor E is arranged in the engine room 10. A driver's seat 12 in which an operator sits is provided in the driver's room 11. In front of the driver's seat 12, a driver's console 14 is provided that is operated by the operator seated in the driver's seat 12 to drive the snowplow 100.

As shown in FIG. 1, the rotary device 2 includes a frame 21, an auger 22, a blower 23, and a snow thrower 24. The frame 21 is connected to the vehicle body 1.

As shown in FIG. 2, the auger 22 is a spiral rotating blade that functions to rake up snow. As shown in FIG. 1, the auger 22 includes a rotating shaft 26 and a spiral blade 27. The auger 22 is rotatably supported by the frame 21 with the rotating shaft 26 extending in the left-right direction at the snow collection port that opens on the front of the snowplow 100. The auger 22 rotates by the rotational power from the prime mover E input through the power transmission path to rake up snow. The blower 23 includes blades and functions to discharge the snow rake up by the auger 22. The blower 23 rotates by the rotational power from the prime mover E input through the power transmission path to blow up the snow rake up by the auger 22. The snow thrower 24 is supported by the frame 21 in a state where it protrudes upward from the frame 21. The snow blown by the blower 23 is guided to the snow thrower 24 and discharged to the side away from the snowplow 100, and then ejected from the snowplow 100.

As shown in FIG. 3, the power transmission mechanism 3 is a mechanism that transmits the rotational power of the prime mover E to the wheels W, the auger 22, and the blower 23, and forms a power transmission path that transmits the rotational power of the prime mover E. The power transmission mechanism 3 includes a transmission 31 including a first clutch 61, a propeller shaft 32, a PTO shaft 33, a torque limiter 34, a power divider 35, a power transmission shaft 36, a transmission mechanism 37, a second clutch 62, a first clutch actuator 41, and a second clutch actuator 42.

The transmission 31 is a mechanism that distributes the input rotational power of the prime mover E and outputs the working power and the traveling power that have been changed to the appropriate torque and rotational speed. The mechanism that distributes the rotational power of the prime mover E to the working power and the traveling power is arranged in the power transmission path upstream of the speed change mechanism. The mechanism that distributes the power and the speed change mechanism may be separate mechanisms. The working power is the power used for snow removal work, and includes the auger driving power and the blower driving power. The transmission 31 includes a transmission case 55 and a plurality of shafts including an input shaft 56, a working power output shaft 57, and a traveling power output shaft 58, which are rotatably supported on the transmission case 55 side via a bearing device. The transmission 31 also has a working power transmission section 48 that links the input shaft 56 and the working power output shaft 57, and a traveling power transmission section 49 that links the input shaft 56 and the traveling power output shaft 58.

The working power transmission section 48 transmits power through a gear and a clutch, and includes a mechanism for switching the gear ratio in multiple stages by selectively connecting and disconnecting the clutch. In this embodiment, the working power transmission section 48 can switch between 1st, 2nd, and 3rd gears, and the clutch for 1st gear is attached to the input shaft 56. In this embodiment, the clutch for 1st gear constitutes the first clutch 61. The first clutch 61 is a hydraulically controlled clutch and is attached to the input shaft 56. In this way, the first clutch 61 is located on the working power transmission path to the auger 22 and the blower 23, and can be switched between a connected state in which the power from the prime mover E is transmitted downstream in the working power transmission direction, and a disconnected state in which the power from the prime mover E is not transmitted downstream in the working power transmission direction. In addition, the first clutch 61 is a friction clutch, and when excessive torque acts, slippage occurs on the friction surface. The working power output shaft 57 is connected to the PTO shaft 33, and the rotation of the working power output shaft 57 rotates the PTO shaft 33. The mechanism that distributes the rotational power of the prime mover E into working power and traveling power is disposed in the power transmission path upstream of the speed change mechanism, so that the traveling power is input to the traveling power transmission section 49 regardless of whether the clutch of the working power transmission section 48 is in the engaged or disengaged state. This allows the snowplow 100 to travel even when the clutch of the working power transmission section 48 is in the disengaged state.

The traveling power transmission section 49 transmits power through a hydraulic pump 65 and a hydraulic motor 66 in addition to gears and clutches. As with the working power transmission section 48, the traveling power transmission section 49 can also switch the gear ratio in multiple stages by selectively connecting and disconnecting the clutch. The hydraulic pump 65 is driven by the driving force transmitted from the input shaft via the gears to generate hydraulic pressure. The hydraulic motor 66 generates rotational power by the hydraulic pressure supplied from the hydraulic pump 65. The rotational power generated by the hydraulic motor 66 is transmitted to the traveling power output shaft 58 via the gears of the traveling power transmission section 49 and output. The traveling power output shaft 58 is connected to the wheels W via the propeller shaft 32, and the propeller shaft 32 and the wheels W rotate due to the rotation of the traveling power output shaft 58.

Figure 4 is a cross-sectional view showing an example of the configuration of the torque limiter 34. The torque limiter 34 is connected to the PTO shaft 33 and is located on the working power transmission path downstream of the first clutch 61. The torque limiter 34 is also located on the working power transmission path upstream of the power divider 35 described later. The torque limiter 34 is a mechanism that suppresses the transmission of torque when the torque acting exceeds a predetermined threshold, and releases the suppression of the torque transmission when the torque acting falls within the predetermined threshold. As shown in Figure 4, in this embodiment, the torque limiter 34 is a disc spring type torque limiting device, and includes an input shaft 71, an output shaft 72, a torque transmission member 73, and a disc spring 74. The torque transmission member 73 rotates integrally with the input shaft 71. The torque transmission member 73 is pressed against the output shaft 72 by the biasing force of the disc spring 74, and engages with the output shaft 72 by frictional force. During normal operation when excessive torque is not applied, the torque limiter 34 transmits torque from the input shaft 71 to the output shaft 72 via the torque transmission member 73. When excessive torque is applied to the input shaft 71 or the output shaft 72, the disc spring 74 elastically deforms, disengaging the torque transmission member 73 from the output shaft 72, causing slippage between the torque transmission member 73 and the output shaft 72, suppressing the transmission of excessive torque. When slippage occurs between the torque transmission member 73 and the output shaft 72, a difference occurs in the rotation speed of the input shaft 71 and the output shaft 72.

As shown in FIG. 3, the power splitter 35 is a gear box and is located on the working power transmission path downstream of the first clutch 61. The power splitter 35 splits the working power from the first clutch 61 into auger drive power and blower drive power, and functions to branch the working power transmission path into an auger drive power transmission path that transmits the auger drive power and a blower drive power transmission path that transmits the blower drive power. The power splitter 35 includes an input shaft 81 connected to the output shaft 72 of the torque limiter 34, a first output shaft 82 located on the blower drive power transmission path and connected to the blower 23, and a second output shaft 83 located on the auger drive power transmission path.

The power transmission shaft 36 and the transmission mechanism 37 are mechanical elements that transmit the auger drive power output from the second output shaft 83 to the second clutch 62. The power transmission shaft 36 is located on the auger drive power transmission path downstream of the second output shaft 83 of the power splitter 35 and is connected to the second output shaft 83. The transmission mechanism 37 is a chain sprocket mechanism, and is located on the auger drive power transmission path downstream of the power transmission shaft 36 and is connected to the power transmission shaft 36.

The second clutch 62 is a hydraulically controlled clutch, and is located on the auger drive power transmission path downstream of the transmission mechanism 37. When hydraulic pressure is supplied to the second clutch 62, the second clutch 62 is in a connected state in which the auger drive power is transmitted downstream in the power transmission direction. When the supply of hydraulic pressure is stopped, the second clutch 62 is switched to a disconnected state in which the auger drive power is not transmitted downstream in the power transmission direction. In this way, the second clutch 62 is a clutch that can be switched between a connected state and a disconnected state. The second clutch 62 is also a friction clutch, and when a torque exceeding a predetermined threshold is applied, slippage occurs inside. As a result, a slight difference occurs in the rotation speed of the input shaft and the output shaft of the second clutch 62.

The first clutch actuator 41 is a hydraulic actuator that switches the first clutch 61 between an engaged state and a disengaged state. The second clutch actuator 42 is a hydraulic actuator that switches the second clutch 62 between an engaged state and a disengaged state.

The snowplow 100 also has sensors that detect the rotation speed of the prime mover E and the rotating mechanical elements in the power transmission path.

The rotation speed of the prime mover E is detected and output by the first sensor 51. The signal output from the first sensor 51 is input to the ECM 5. The first sensor 51 is an engine rotation sensor that detects the rotation speed of a rotating mechanical element such as a flywheel of the prime mover E, and is, for example, a sensor that is attached to the prime mover E during manufacture.

In addition, a second sensor 52 is provided in the working power transmission path to detect the rotation speed of the first rotating mechanical element 18, which is a mechanical element such as a shaft or gear that transmits the power from the first clutch 61 to the second clutch 62 or the power from the power splitter 35 to the blower 23. In this embodiment, the first rotating mechanical element 18 is a spur gear and is fixed to the power transmission shaft 36. The second sensor 52 is disposed close to the tip of the teeth of the first rotating mechanical element 18, detects the movement of the tip of the teeth of the first rotating mechanical element 18, and generates a signal having a frequency component proportional to the rotation speed of the power transmission shaft 36. The second sensor 52 then generates and outputs a signal having the frequency component or a signal including rotation speed information calculated based on the frequency component.

Furthermore, a third sensor 53 is provided in the working power transmission path to detect the rotation speed of the second rotating mechanical element 28, which is a mechanical element such as a shaft or gear that transmits power from the second clutch 62 to the auger 22. In this embodiment, the second rotating mechanical element 28 is a spur gear and is fixed to the rotating shaft 26 of the auger 22. The third sensor 53 is disposed close to the tip of the teeth of the second rotating mechanical element 28, detects the movement of the tip of the teeth of the second rotating mechanical element 28, and generates a signal having a frequency component proportional to the rotation speed of the rotating shaft 26. The third sensor 53 then generates and outputs a signal having the frequency component or a signal including rotation speed information calculated based on the frequency component.

Figure 5 is a block diagram showing an example of the configuration of the control system of the snowplow 100. As shown in Figure 5, an input device 15 is provided on the driver's console 14 located in the driver's cab 11. The input device 15 is a device, such as a push button, that accepts a return command to switch the first clutch 61 or the second clutch 62 from the disconnected state to the connected state.

The controller 4 is an electric circuit, for example, having a processor with a computing unit such as a CPU, and memories such as ROM and RAM. The controller 4 may be configured as a single controller for centralized control, or may be configured as multiple controllers for distributed control in cooperation with each other.

The controller 4 is electrically connected to the ECM 5, the second sensor 52, the third sensor 53, and the input device 15, and receives information including the engine speed detected by the first sensor 51, the speed of the first rotating mechanical element 18 detected by the second sensor 52, the speed of the second rotating mechanical element 28 detected by the third sensor 53, and a return command. The controller 4 receives the engine speed detected by the first sensor 51 via a control area network (CAN).

Furthermore, the controller 4 controls the first clutch actuator 41 and the second clutch actuator 42, thereby switching between connection and disconnection of the first clutch 61 and the second clutch 62. In this embodiment, the controller 4 controls the operation of a valve that switches between supplying and stopping hydraulic pressure to each of the first clutch actuator 41 and the second clutch actuator 42, thereby controlling the first clutch actuator 41 and the second clutch actuator 42, and switching between connection and disconnection of the first clutch actuator 41 and the second clutch actuator 42.

[Example of operation]
Next, an example of the operation of the snowplow 100 will be described.

During snow removal, the rotational power from the prime mover E rotates the wheels W, moving the snowplow 100 forward and collecting snow from the snow collection port of the rotary device 2. When the controller 4 switches the first clutch 61 and the second clutch 62 to the connected state, the rotational power from the prime mover E rotates the auger 22, which then scoops up the snow. The collected snow is blown away by the blades of the blower 23, which rotates due to the rotational power from the prime mover E, and is guided to the snow dump 24 and discharged from the snowplow 100.

In the above state, the controller 4 performs the disengagement control of the first clutch 61 and the disengagement control of the second clutch 62. Note that the disengagement control of the first clutch 61 and the disengagement control of the second clutch 62 are performed in parallel.

Figure 6 is a flowchart showing an example of the operation of the snowplow 100, and is a flowchart showing the disconnection control of the first clutch 61. In the disconnection control of the first clutch 61, the controller 4 first determines whether the first clutch 61 is in an engaged state (step S10). Then, when the controller 4 determines that the first clutch 61 is in a disengaged state (No in step S10), it ends the disconnection control of the first clutch 61.

On the other hand, when the controller 4 determines that the first clutch 61 is in an engaged state (Yes in step S10), it calculates a first reference rotation speed (step S11). The first reference rotation speed is the rotation speed of the first rotating mechanical element 18 when the first clutch 61 and the second clutch 62 are in an engaged state, and is the rotation speed of the first rotating mechanical element 18 corresponding to the rotation speed of the prime mover E detected by the first sensor 51. In this embodiment, the controller 4 calculates the first reference rotation speed by multiplying the rotation speed of the prime mover E detected by the first sensor 51 by the reduction ratio from the prime mover E to the power transmission shaft 36, including the gear ratio in the transmission 31.

Next, the controller 4 calculates a first slippage amount (step S12). The first slippage amount is the difference between the first reference rotation speed and the rotation speed of the first rotating mechanical element 18 detected by the second sensor 52.

Next, the controller 4 determines whether the first slippage exceeds a predetermined threshold value (step S13). The first reference rotation speed is the rotation speed of the first rotating mechanical element 18 when the first clutch 61 and the second clutch 62 are engaged. Therefore, during normal times when snow removal work is proceeding smoothly, the difference between the first reference rotation speed and the rotation speed of the first rotating mechanical element 18 detected by the second sensor 52 is very small, and the first slippage falls within the predetermined threshold value. As a result, the controller 4 determines that the first slippage does not exceed the predetermined threshold value (No in step S13) and performs the determination in step S11 again.

On the other hand, when the blades of the blower 23 get caught in something, such as a stone or ice block, and the rotation of the blades of the blower 23 is hindered, slippage occurs in the torque limiter 34, and a difference occurs between the rotation speeds of the input shaft 71 and the output shaft 72 of the torque limiter 34. Then, the first slippage exceeds a predetermined threshold, and the controller 4 determines that the first slippage exceeds the predetermined threshold (Yes in step S13). Then, the controller 4 switches the first clutch 61 to a disconnected state (step S14). This cuts off the supply of power to the auger 22 and the blower 23, and the auger 22 and the blower 23 stop. Then, the controller 4 ends the disconnection control of the first clutch 61. The above threshold is a value at which the first clutch 61 can be immediately switched to a disconnected state when slippage occurs in the torque limiter 34 due to the rotation of the blades of the blower 23 being hindered, and is a value set by experiment, simulation, calculation, etc.

In this way, when the rotation of the blades of the blower 23 is impeded, the torque increases, causing slippage in the section of the power transmission path between the prime mover E and the first rotating mechanical element 18, and the controller 4 immediately switches the first clutch 61 to a disconnected state to stop the blower 23 and the auger 22. This makes it possible to prevent failures caused by the application of large forces to the power transmission mechanism 3 and the prime mover E, such as burning of the clutch plates.

In addition, the first clutch 61 is switched to a disconnected state when slippage occurs in the torque limiter 34, so the torque threshold value that the torque limiter 34 suppresses transmission can be set appropriately. This allows the first clutch 61 to be operated under appropriate conditions. More specifically, the clutch of the working power transmission section of the transmission 31 may be a friction clutch, and the first clutch 61 may be disconnected when slippage occurs in this clutch. However, the clutch of the transmission 31 is usually designed to withstand a relatively large torque, and slippage may not occur in the transmission 31 even when the blower 23 has caught a somewhat large stone. However, in this embodiment, the controller 4 uses the slippage of the torque limiter 34 to determine that the rotation of the blades of the blower 23 has been inhibited, so the torque threshold value that the torque limiter 34 suppresses transmission can be set to an appropriate value, and the first clutch 61 can be operated under appropriate conditions.

Figure 7 is a flowchart showing an example of the operation of the snowplow 100, and is a flowchart showing the disconnection control of the second clutch 62. In the disconnection control of the second clutch 62, the controller 4 first determines whether the second clutch 62 is in an engaged state (step S20). Then, when the controller 4 determines that the second clutch 62 is in a disconnected state (No in step S20), it ends the disconnection control of the second clutch 62.

On the other hand, when the controller 4 determines that the second clutch 62 is in an engaged state (Yes in step S20), it calculates a second reference rotation speed (step S21). The second reference rotation speed is the rotation speed of the second rotating mechanical element 28 when the first clutch 61 and the second clutch 62 are in an engaged state, and is the rotation speed of the second rotating mechanical element 28 corresponding to the rotation speed of the prime mover E detected by the first sensor 51. In this embodiment, the controller 4 calculates the second reference rotation speed by multiplying the rotation speed of the prime mover E detected by the first sensor 51 by the reduction ratio from the prime mover E to the rotating shaft 26 of the auger 22, including the gear ratio in the transmission 31.

Next, the controller 4 calculates the second slippage (step S22). The second slippage is the difference between the second reference rotation speed and the rotation speed of the second rotating mechanical element 28 detected by the third sensor 53.

Next, the controller 4 determines whether the second slippage exceeds a predetermined threshold value (step S23). The second reference rotation speed is the rotation speed of the second rotating mechanical element 28 when the first clutch 61 and the second clutch 62 are engaged. Therefore, during normal times when snow removal work is proceeding smoothly, the difference between the second reference rotation speed and the rotation speed of the second rotating mechanical element 28 detected by the third sensor 53 is very small, and the second slippage falls within the predetermined threshold value. As a result, the controller 4 determines that the second slippage does not exceed the predetermined threshold value (No in step S23) and performs the determination in step S21 again.

On the other hand, when the auger 22 gets caught in a stone or ice block, for example, and the rotation of the auger 22 is hindered, slippage occurs in the second clutch 62, and a difference occurs between the rotation speeds of the input shaft and the output shaft of the second clutch 62. Then, the second slippage exceeds a predetermined threshold, and the controller 4 determines that the second slippage exceeds the predetermined threshold (Yes in step S23). Then, the controller 4 switches the second clutch 62 to a disconnected state (step S24). This cuts off the supply of power to the auger 22, and the auger 22 stops. Then, the controller 4 ends the disconnection control of the second clutch 62. The above threshold is a value at which the second clutch 62 can be immediately switched to a disconnected state when slippage occurs in the second clutch 62 due to the rotation of the auger 22 being hindered, and is a value set by experiment, simulation, calculation, etc.

When the rotation of the auger 22 is inhibited in this way, the torque increases, causing slippage in the section of the power transmission path between the prime mover E and the second rotating mechanical element 28, and the controller 4 immediately switches the second clutch 62 to a disconnected state to stop the auger 22. This prevents breakdowns caused by a large force being applied to the power transmission mechanism 3 and the prime mover E, such as burning of the clutch plate. In addition, when the second clutch 62 is disconnected, the blower 23 is in operation, so snow inside the vehicle body 1 is discharged. This reduces the work of shoveling out snow that remains inside the vehicle body and hinders the resumption of snow removal work. Therefore, snow removal work can be resumed quickly. In addition, since the first sensor 51 is shared as the input side sensor used to calculate the first slippage amount and the second slippage amount, the configuration for detecting the rotation speed of the input shaft 71 of the torque limiter 34 and the input shaft of the second clutch 62 can be simplified.

When one or both of the first clutch 61 and the second clutch 62 are in a disconnected state due to the disconnection control of the first clutch 61 and the disconnection control of the second clutch 62, the controller 4 then performs return control. FIG. 8 is a flowchart showing an example of the operation of the snowplow 100, and is a flowchart showing the return control. In the return control, the controller 4 first determines whether one or both of the first clutch 61 and the second clutch 62 are in a disconnected state (step S30). Then, when the controller 4 determines that one or both of the first clutch 61 and the second clutch 62 are not in a disconnected state, i.e., are in a connected state (No in step S30), the return control ends.

On the other hand, when the controller 4 determines that one or both of the first clutch 61 and the second clutch 62 are in a disconnected state (Yes in step S30), it activates the input device 15 (step S31). Activation means that the controller 4 is able to accept a return command via the input device 15 to switch the first clutch 61 or the second clutch 62, which is in a disconnected state, to a connected state.

Next, the controller 4 waits until the input device 15 receives a return command (step S32).

Next, when the input device 15 receives a return command, the first clutch 61 or the second clutch 62 is switched to the connected state. This activates the auger 22 and the blower 23. In this way, the first clutch 61 and the second clutch 62 can be switched to the connected state by operation from the driver's cab 11, and snow removal work can be resumed quickly.

(Modification)
In the above embodiment, the clutch of the transmission 31 and the second clutch 62 are friction clutches, but the present invention is not limited to this configuration. Instead of this configuration, a centrifugal clutch or an electromagnetic clutch may be used.

In the above embodiment, the second clutch 62 performs both the function of switching between transmission and interruption of the auger drive power and the function of causing slippage due to overload, which is an event that triggers clutch switching, but is not limited to this configuration. Instead of this configuration, for example, a torque limiter may be provided in the auger drive power transmission path, and the torque limiter may perform the function of causing slippage due to overload.

In the above embodiment, the signal output from the first sensor 51 is input to the controller 4 via the ECM 5, but this is not limited to the above configuration. Instead, the signal may be input directly to the controller 4.

In the above embodiment, the controller 4 and the ECM 5 are separate controllers, but this is not limited to the configuration. Instead of this configuration, the controller 4 and the ECM 5 may be one controller.

In the above embodiment, the first clutch 61 is a clutch for first gear of the working power transmission section 48 of the transmission 31, but is not limited to this configuration. Instead of this configuration, the first clutch 61 may be a clutch provided separately at any point in the range from the input shaft 56 of the transmission 31 to the input shaft 71 of the torque limiter 34 in the working power transmission path.

(List of embodiments)
A snowplow in which rotational power from a prime mover is input via a power transmission path to an auger that rakes up snow and a blower that ejects the snow rake up by the auger,
a first clutch located on the power transmission path and switchable between a connected state in which power from the prime mover is transmitted downstream in a power transmission direction and a disconnected state in which power from the prime mover is not transmitted downstream in the power transmission direction;
a power divider that is located on the power transmission path downstream of the first clutch, divides power from the first clutch into auger drive power and blower drive power, and branches the power transmission path into an auger drive power transmission path that transmits the auger drive power and a blower drive power transmission path that transmits the blower drive power;
a second clutch located on the auger driving power transmission path and switchable between a connected state in which the auger driving power is transmitted downstream in a power transmission direction and a disconnected state in which the auger driving power is not transmitted downstream in the power transmission direction;
a first clutch actuator that switches between the engaged state and the disengaged state of the first clutch;
a second clutch actuator that switches between the engaged state and the disengaged state of the second clutch;
A first sensor that detects a rotation speed of the prime mover;
a second sensor that detects the rotation speed of a first rotating mechanical element that transmits power from the first clutch to the second clutch or power from the power splitter to the blower;
a third sensor that detects the rotation speed of a second rotating mechanical element that transmits power from the second clutch to the auger;
a controller that controls the first clutch actuator and the second clutch actuator,
The controller includes:
switching the first clutch to the disengaged state when a first slippage, which is a difference between a first reference rotation speed, which is the rotation speed of the first rotating mechanical element corresponding to the rotation speed of the prime mover detected by the first sensor, and the rotation speed of the first rotating mechanical element detected by the second sensor, exceeds a predetermined threshold value;
A snowplow, in which the second clutch is switched to the disengaged state when a second slippage amount, which is the difference between a second reference rotation speed, which is the rotation speed of the second rotating mechanical element corresponding to the rotation speed of the prime mover detected by the first sensor, and the rotation speed of the second rotating mechanical element detected by the third sensor, exceeds a predetermined threshold value.

With this configuration, when the second clutch is disconnected to stop the auger, the blower can be left operating, preventing the collected snow from accumulating inside the vehicle body. This allows snow removal work to be resumed quickly. In addition, the first sensor is shared as the input sensor used to calculate the first slippage amount and the second slippage amount, making it possible to simplify the configuration.

Embodiment 2: The snowplow described in embodiment 1, further comprising a torque limiter located on the power transmission path downstream of the first clutch and upstream of the power divider, which inhibits the transmission of torque when the applied torque exceeds a predetermined threshold and releases the inhibition of the torque transmission when the applied torque falls within the predetermined threshold.

With this configuration, the torque threshold at which the torque limiter suppresses transmission can be appropriately set, and the operating conditions of the first clutch can be set to appropriate conditions.

Embodiment 3: A crew cabin;
An input device located in the driver's compartment for receiving a return command to switch the first clutch or the second clutch in the disconnected state to the connected state,
The snowplow according to embodiment 1 or 2, wherein when the input device receives the return command, the controller switches the first clutch or the second clutch, which is in the disengaged state, to the engaged state.

With this configuration, the first clutch and the second clutch can be switched to the connected state by operating from the driver's cab, allowing snow removal work to be resumed quickly.

Fourth embodiment: A method for controlling a snowplow in which rotational power from a prime mover is input via a power transmission path to an auger that rakes up snow and a blower that ejects the snow rake up by the auger, comprising:
The snowplow,
a first clutch located on the power transmission path and switchable between a connected state in which power from the prime mover is transmitted downstream in a power transmission direction and a disconnected state in which power from the prime mover is not transmitted downstream in the power transmission direction;
a power divider that is located on the power transmission path downstream of the first clutch, divides power from the first clutch into auger drive power and blower drive power, and branches the power transmission path into an auger drive power transmission path that transmits the auger drive power and a blower drive power transmission path that transmits the blower drive power;
a second clutch located on the auger driving power transmission path and switchable between a connected state in which the auger driving power is transmitted downstream in a power transmission direction and a disconnected state in which the auger driving power is not transmitted downstream in the power transmission direction;
a first rotating machine element that transmits power from the first clutch to the second clutch or power from the power splitter to the blower;
a second rotating mechanical element that transmits power from the second clutch to the auger,
Detecting the rotation speeds of the prime mover, the first rotating mechanical element, and the second rotating mechanical element;
calculating a first reference rotation speed, which is a rotation speed of the first rotating mechanical element when the first clutch and the second clutch are in the engaged state and corresponds to the detected rotation speed of the prime mover;
Calculating a first slippage amount that is a difference between the first reference rotation speed and the detected rotation speed of the first rotating mechanical element;
When the first slippage exceeds a predetermined threshold, the first clutch is switched to the disengaged state,
calculating a second reference rotation speed, which is a rotation speed of the second rotating mechanical element when the first clutch and the second clutch are in the engaged state and corresponds to the detected rotation speed of the prime mover;
Calculating a second slippage amount that is a difference between the second reference rotation speed and the detected rotation speed of the second rotating mechanical element;
A method for controlling a snowplow, comprising: switching the second clutch to the disengaged state when the second slippage exceeds a predetermined threshold value.

With this configuration, the blower can be kept operating when the second clutch is activated, preventing collected snow from accumulating inside the vehicle body. This allows snow removal work to be resumed quickly. In addition, the engine speed is shared as the input information used to calculate the first slippage amount and the second slippage amount, making it possible to simplify the configuration.

From the above description, many modifications and other embodiments of the present invention will be apparent to those skilled in the art. Therefore, the above description should be interpreted as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the present invention. Details of the structure and/or function of the present invention may be substantially changed without departing from the spirit of the present invention.

LIST OF REFERENCE NUMERALS E Prime mover W Wheel 1 Vehicle body 2 Rotary device 3 Power transmission mechanism 4 Controller 11 Crew cabin 15 Input device 18 First rotating machine element 21 Frame 22 Auger 23 Blower 24 Snow thrower 26 Rotating shaft 27 Blade 28 Second rotating machine element 31 Transmission 32 Propeller shaft 34 Torque limiter 35 Power splitter 36 Power transmission shaft 41 First clutch actuator 42 Second clutch actuator 46 Control unit 47 Memory unit 51 First sensor 52 Second sensor 53 Third sensor 56 Input shaft 57 Working power output shaft 58 Traveling power output shaft 61 First clutch 62 Second clutch 71 Input shaft 72 Output shaft 73 Torque transmission member 74 Disc spring 100 Snowplow

Claims (4)

A snowplow in which rotational power from a prime mover is input to an auger that rakes up snow and a blower that discharges the snow rake up by the auger via a power transmission path,
a first clutch located on the power transmission path and switchable between a connected state in which power from the prime mover is transmitted downstream in a power transmission direction and a disconnected state in which power from the prime mover is not transmitted downstream in the power transmission direction;
a power divider that is located on the power transmission path downstream of the first clutch, divides power from the first clutch into auger drive power and blower drive power, and branches the power transmission path into an auger drive power transmission path that transmits the auger drive power and a blower drive power transmission path that transmits the blower drive power;
a second clutch located on the auger driving power transmission path and switchable between a connected state in which the auger driving power is transmitted downstream in a power transmission direction and a disconnected state in which the auger driving power is not transmitted downstream in the power transmission direction;
a first clutch actuator that switches between the engaged state and the disengaged state of the first clutch;
a second clutch actuator that switches between the engaged state and the disengaged state of the second clutch;
A first sensor that detects a rotation speed of the prime mover;
a second sensor that detects the rotation speed of a first rotating mechanical element that transmits power from the first clutch to the second clutch or power from the power splitter to the blower;
a third sensor that detects the rotation speed of a second rotating mechanical element that transmits power from the second clutch to the auger;
a controller that controls the first clutch actuator and the second clutch actuator,
The controller includes:
switching the first clutch to the disengaged state when a first slippage, which is a difference between a first reference rotation speed, which is the rotation speed of the first rotating mechanical element corresponding to the rotation speed of the prime mover detected by the first sensor, and the rotation speed of the first rotating mechanical element detected by the second sensor, exceeds a predetermined threshold value;
A snowplow, in which the second clutch is switched to the disengaged state when a second slippage amount, which is the difference between a second reference rotation speed, which is the rotation speed of the second rotating mechanical element corresponding to the rotation speed of the prime mover detected by the first sensor, and the rotation speed of the second rotating mechanical element detected by the third sensor, exceeds a predetermined threshold value. The snowplow according to claim 1, further comprising a torque limiter located on the power transmission path downstream of the first clutch and upstream of the power divider, which suppresses the transmission of torque when the applied torque exceeds a predetermined threshold value, and releases the suppression of the transmission of torque when the applied torque falls within the predetermined threshold value. The crew compartment and
An input device located in the driver's compartment for receiving a return command to switch the first clutch or the second clutch in the disconnected state to the connected state,
The snowplow according to claim 1 or 2, wherein the controller switches the first clutch or the second clutch from the disengaged state to the engaged state when the input device receives the return command. A method for controlling a snowplow in which rotational power from a prime mover is input via a power transmission path to an auger that rakes up snow and a blower that discharges the snow rake up by the auger, comprising:
The snowplow,
a first clutch located on the power transmission path and switchable between a connected state in which power from the prime mover is transmitted downstream in a power transmission direction and a disconnected state in which power from the prime mover is not transmitted downstream in the power transmission direction;
a power divider that is located on the power transmission path downstream of the first clutch, divides power from the first clutch into auger drive power and blower drive power, and branches the power transmission path into an auger drive power transmission path that transmits the auger drive power and a blower drive power transmission path that transmits the blower drive power;
a second clutch located on the auger driving power transmission path and switchable between a connected state in which the auger driving power is transmitted downstream in a power transmission direction and a disconnected state in which the auger driving power is not transmitted downstream in the power transmission direction;
a first rotating machine element that transmits power from the first clutch to the second clutch or power from the power splitter to the blower;
a second rotating mechanical element that transmits power from the second clutch to the auger,
Detecting the rotation speeds of the prime mover, the first rotating mechanical element, and the second rotating mechanical element;
calculating a first reference rotation speed, which is a rotation speed of the first rotating mechanical element when the first clutch and the second clutch are in the engaged state and corresponds to the detected rotation speed of the prime mover;
Calculating a first slippage amount that is a difference between the first reference rotation speed and the detected rotation speed of the first rotating mechanical element;
When the first slippage exceeds a predetermined threshold, the first clutch is switched to the disengaged state,
calculating a second reference rotation speed, which is a rotation speed of the second rotating mechanical element when the first clutch and the second clutch are in the engaged state and corresponds to the detected rotation speed of the prime mover;
Calculating a second slippage amount that is a difference between the second reference rotation speed and the detected rotation speed of the second rotating mechanical element;
A method for controlling a snowplow, comprising: switching the second clutch to the disengaged state when the second slippage exceeds a predetermined threshold value.

Images