JP2843787B2 - Auger drive mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auger drive mechanism for a rotary snowplow.

[0002]

2. Description of the Related Art As shown in FIG. 4, a rotary snowplow is provided with a snow removal device 2 comprising an auger 3, a blower 4 and a chute 5 at the front of a vehicle body 1, and the auger 3 scrapes snow on the road to blow the snow. Thus, snow is thrown to an appropriate place outside the road via the chute 5.

FIG. 5 shows an auger and blower drive mechanism of a general rotary snowplow. As shown in this figure, the power generated by the engine 6 is transmitted by the transmission 7 and the transmission 8.
And transmitted to the auger 3 through the chain transmission 9, when the auger 3 bites, for example, a stone or an ice block, an abnormally large torque is generated and a large force is applied to the engine or the transmission to cause a failure. Becomes So, usually,
The shaft between the chain transmission 9 and the auger 3 is provided with a torque limiting device for limiting the upper limit of the transmission torque.

Heretofore, as a torque limiting device mounted on an auger drive mechanism of a rotary snowplow, a shear pin has been widely adopted because of its simple structure. The shear pin includes a flange 10 provided at a shaft end on a driving side and a flange 1 provided on a shaft end on a driven side so as to face the flange 10.
1 is tightened with a shear pin (not shown) configured as a bolt having a groove around it, torque is transmitted from the drive shaft to the driven shaft via the shear pin, and when the torque exceeds a predetermined limit torque, the The transmission torque is limited by setting the cross-sectional area of the portion surrounded by the groove of the shear pin so as to be cut by shearing.

Although the structure of the shear pin as the torque limiting device is simple, if it is cut, it takes time to replace the shear pin. In particular, if a rotary snowplow uses an auger drive mechanism for the auger drive, the snowplow is only active during the severe winter when snow is heavy, and it is necessary to remove the snow accumulated in the surrounding area before replacing the pin. In addition, there is a drawback that work efficiency is reduced due to difficulty in operation due to cold outdoors and difficulty in fingertips. In addition, a working tool such as a spare pin or a spanner must be prepared in advance.

[0006] A disk spring type torque limiting device has been devised and put into practical use in order to solve such a problem. This disc spring type torque limiting device, for example, pivotally attaches a torque transmitting member urged by a disc spring to a drive side member, and provides a concave portion in which a part of the torque transmitting member engages a driven side member. The torque is transmitted from the driving side to the driven side via the torque transmitting member, and when excessive torque is applied, the torque transmitting member and the driven side member are opposed to the urging force of the disk spring (the disk spring is elastically deformed). Are released to release the torque.

[0007]

However, the conventional disc spring type torque limiting device has a large size and a large weight, and there is a problem that an auger drive mechanism using the same is inevitably increased in size and weight. In addition, there is another problem that the auger needs to be reversed for the reset (reset) operation from the torque release state to the transmission state, which is troublesome.

The present invention solves the above-mentioned problem in the conventional auger drive mechanism, and when the excessive torque is applied, the transmission of the drive power is reliably released, and the drive power is automatically transmitted by a simple operation. It is an object to provide an auger drive mechanism that can be reset to a possible state.

[0009]

According to the present invention, there is provided an auger drive mechanism for a rotary snowplow having a torque limiting device between a driven shaft having an auger mounted thereon and a drive shaft for driving the driven shaft. A hydraulic clutch as the torque limiting device, a hydraulically operable hydraulic supply switching valve for switching between supply and cutoff of hydraulic pressure to a hydraulic circuit in the hydraulic circuit, and a relief for setting the hydraulic pressure of the circuit; A control means for controlling a switching operation of the two switching valves, the control means having a remotely controllable hydraulic pressure holding switching valve for switching between holding and releasing of the hydraulic pressure supplied to the circuit; and Instruction means for instructing the supply of hydraulic pressure to the circuit, and detection means for detecting that a predetermined torque difference has occurred between the drive shaft and the driven shaft of the auger are provided, and the detection means is provided with a drive shaft of the auger. Follower When it is detected that a predetermined torque difference has occurred during the period, the control means switches the hydraulic pressure holding switching valve to the hydraulic pressure release position based on a signal from the detection means, and receives an instruction from the instruction means. In this case, the problem is solved by the control means switching the hydraulic pressure holding switching valve to the hydraulic pressure holding position and switching the hydraulic pressure supply switching valve to the hydraulic pressure supplying position.

Further, the present invention proposes, in order to solve the above-mentioned problem, that the on-off pressure of the hydraulic clutch is adjusted by adjusting the pressure of the relief valve, and the opening torque of the torque limiting device is set. .

Further, according to the present invention, in order to solve the above-mentioned problems, as the detecting means, a rotational speed detecting means for detecting a rotational speed of a drive shaft of the auger and a rotational speed detecting means for detecting a rotational speed of a driven shaft. It is proposed that a predetermined torque difference be generated when a difference occurs between the rotation speeds detected by the both rotation speed detection units.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway front view showing a main part of an embodiment of an auger drive mechanism of the present invention, and shows an auger of a rotary snowplow and a torque limiting device. In this figure, a drive shaft 21 for driving the auger 3 is fixed to a sprocket of the chain transmission 9 shown in FIG. 5, and is driven to rotate by the engine 6 of the snowplow. However, unlike the conventional auger drive mechanism of FIG. 5, no shear pin is used between the drive side and the driven side. In the present embodiment, a torque limiting device 20 is provided between an auger shaft (driven shaft) 22 on which the auger 3 is mounted and the drive shaft 21. The torque limiting device 20 has a built-in hydraulic clutch 23. Normally (during snow removal work), the hydraulic clutch 23 is in a torque transmitting state, and the rotation of the drive shaft 21 (driving force)
Is transmitted to the driven shaft 22 via the torque limiting device 20, and rotates the auger 3 to remove snow cover (see FIG. 4).
Scrape inside. When the auger 3 bites, for example, rocks or ice blocks and generates excessive torque, the hydraulic clutch 23
Is shut off to release torque and prevent adverse effects on the engine and auger drive mechanism.

FIG. 2 is a sectional view showing the structure of the hydraulic clutch 23. Hydraulic clutch 23 in torque limiting device
Is disposed between the drive shaft 21 and the driven shaft 22, and the oil chamber 2
4 is a wet-type hydraulic clutch having a clutch plate 25 therein. The clutch plate 25 is composed of a plurality of clutch plates supported and alternately provided on the drive side housing and the driven side housing, respectively. When a hydraulic pressure is supplied into the oil chamber 24 from a hydraulic pump described later, the clutch plate 25 The plate 25 is pressed to transmit the driving force. When the hydraulic pressure is released to the drain tank via a solenoid valve described later, the pressing of the clutch plate 25 is released,
The transmission of the driving force is released.

FIG. 3 is a circuit diagram showing an electric and hydraulic circuit configuration according to this embodiment. The hydraulic circuit shown in this figure includes a working hydraulic pump 30, solenoid valves 31, 3
2, 33, a rotary joint 34, a drain tank 35, pressure switches 36a and 36b, a relief valve 37, an accumulator 38, a check valve 39, and a hydraulic clutch 23. The hydraulic pump 30 is a working hydraulic pump used for controlling the snow removing device, and the hydraulic pressure of the pump 30 is supplied to an actuator (not shown) for controlling the snow removing device via a control valve 40 so as to raise and lower the snow removing device. Tilt and shoot up / down and rotation. In this embodiment, the hydraulic pressure of the working hydraulic pump 30 is diverted to the torque limiting device, and the hydraulic clutch 23 is connected and disconnected.

A solenoid valve 32 is a switching valve for supplying hydraulic pressure for switching supply and cutoff of the hydraulic pressure to the hydraulic circuit, and a solenoid valve 33 is a switching valve for retaining hydraulic pressure in the hydraulic circuit for switching between holding and releasing the hydraulic pressure. is there.
The pressure switch 36a is turned off when the pressure on the torque limiting device side is lower than a predetermined lower limit pressure, and outputs an ON signal when the pressure is equal to or higher than the lower limit pressure. The pressure switch 36b
Is OFF when the pressure on the torque limiting device side is lower than a predetermined set pressure.
Outputs N signal.

On the other hand, an electric circuit for detecting the load condition in the auger drive mechanism and controlling the hydraulic clutch 23 includes a controller 41 as a center, a pressure supply switch 42, a disconnection switch 43, and a work neutral (N). It comprises a switch 44, a drive-side rotation sensor 45, a driven-side rotation sensor 46, pilot lamps 47a and 47b, and the like. The controller 41 is control means for controlling the switching operation of the solenoid valves 32 and 33 described above.

The controller 41 includes control elements 48, 4
9, 50, a comparator 51 and a switching element 52. The control element 48 is a pressure switch 36a (lower limit).
Outputs an ON signal when is ON and the pressure switch 36b (set pressure) is OFF. When the pressure supply switch 42 is pressed, the control element 49 outputs an ON signal (outputs for a maximum of 10 seconds). However, this ON signal is output only when the work neutral switch 44 is ON. The control element 49 stops outputting when the pressure switch 36b is turned on. When the pressure supply switch 42 is pressed, the control element 50 outputs an ON signal, and the disconnection switch 43
Is stopped and when there is a signal from the comparator 51, the output is stopped. The pressure supply switch 42 and the disconnection switch 43 are turned on when pressed, but turned off when the finger is released. The controller 41
Is described as a configuration including each control element and the like in order to make the function of the controller easy to understand, but a processor such as a microcomputer can also be used.

In the circuit configured as described above, when the work neutral switch 44 is in the ON state (the state in which the snow removing work is not performed), the pressure supply switch 42 is turned on.
Is turned on, the control element 49 of the controller 41
N signal is output and the solenoid valve 31 is turned to the shut-off position.
The solenoid valves 32 are each switched to the circulation position. Thus, the hydraulic pressure from the hydraulic pump 30 is supplied to the torque limiting device. The supplied hydraulic pressure is sent to the hydraulic clutch 23 of the torque limiting device via the rotary joint 34, but is increased in pressure via the relief valve 37 to a preset pressure. In the present embodiment, since the set pressure of the relief valve 37 determines the pressure for pressing the clutch plate of the hydraulic clutch 23, the opening torque of the torque limiting device (by the conventional shear pin device) is adjusted by adjusting the set pressure of the relief valve 37. In other words, it is possible to easily set the shear pin cutting torque).
The hydraulic pressure supplied to the torque limiting device is stored in the accumulator 3
8 and the check valve 39.

The supply and stop of the hydraulic pressure to the torque limiting device are performed by the controller 41 based on the outputs of the pressure switches 36a and 36b. That is, when the oil pressure on the torque limiting device side is equal to or lower than the predetermined lower limit pressure, the pressure switch 3
6a and 36b are both OFF and the control element 48 is O
The control element 49 outputs an ON signal when the pressure supply switch 42 is turned on, and the solenoid valve 3 is turned on.
Hydraulic pressure is supplied to the torque limiting device by switching 1 and 32 respectively. When the pressure is equal to or higher than the lower limit pressure and lower than the set pressure, the pressure switch 36a is turned on and the pressure 36b is turned off, so that the control element 48 outputs an ON signal and the supply of hydraulic pressure to the torque limiting device is continued. Then, when the pressure becomes equal to or higher than the set pressure, the control elements 48 and 49 are both turned off by turning on the pressure switch 36b, the solenoid valves 31 and 32 are switched to the states shown in the drawing, and the supply of the hydraulic pressure is stopped. The pressure switch 3
When 6a is OFF, the switching element 52 is switched to the lower side, and a red lamp indicating that the clutch 23 is disconnected is turned on. When the pressure switch 36a is turned on, the switching element 52 switches to the upper side, and a green lamp indicating the connection of the clutch 23 is turned on.

In this embodiment, proximity switches are used as the rotation sensors 45 and 46, and the occurrence of excessive torque is determined based on the relative relationship between the pulses on the drive shaft side and the driven shaft side detected by both sensors. That is, when stones or ice blocks are caught in the auger 3 and an excessive torque is generated between the drive shaft and the driven shaft, slippage occurs between the clutch plate 25 (see FIG. 2) of the hydraulic clutch 23 and the drive side and the drive side. A difference occurs in the rotation speed on the driven side. The detection signals of both sensors 45 and 46 are constantly monitored by the controller 41,
When the comparator 51 detects a difference between the number of rotations on the driving side and the number of rotations on the driven side, the output of the ON signal of the control element 50 is stopped, and the solenoid valve 33 switches from the shut-off position to the circulation position (the state shown in the drawing). Can be Then, the hydraulic pressure on the torque limiting device side flows to the drain tank 35, the hydraulic clutch 23 is disengaged, and the torque is released. Therefore, it is possible to prevent a failure of the chain transmission and the engine due to the overload. FIG. 3 shows the torque released state in which the hydraulic clutch 23 is disengaged, as can be seen from the fact that the solenoid valve 33 is at the circulation position.

When the transmission of the driving force to the auger 3 is manually released (clutch 23 is disconnected), the output of the ON signal of the control element 50 is stopped by pressing the disconnection switch 43, and the solenoid valve is turned off. 33 is switched to the distribution position.

In this embodiment, the opening pressure due to excessive torque can be easily changed by adjusting the set pressure of the relief valve 37. Further, resetting after releasing the torque can be performed very easily only by pressing the pressure supply switch 42. By providing switches such as the pressure supply switch 42 and the disconnection switch 43 on the driver's seat of the snowplow, the connection and disconnection of the auger driving force can be remotely controlled. Further, the size of the torque limiting device can be reduced, so that the auger's ability to transport snow can be improved. In addition, the right and left weight balance of the snow removing device can be improved with the weight reduction of the torque limiting device (less than half of the conventional disc spring type). In the conventional auger drive mechanism using the disc spring type torque limiting device, it was necessary to disassemble the torque limiting device and adjust the spring force, which required a great deal of trouble. Also, resetting after the torque was released required the auger to be reversed, which was troublesome. Such disadvantages of the conventional device have been solved by the present invention, and it has become possible to significantly reduce the burden on the snow plow driver and the snow plow operator.

[0023]

As described above, according to the auger drive mechanism of the present invention, resetting after the drive force is cut off due to the generation of excessive torque can be easily performed by remote control. Further, by using the hydraulic clutch, the torque limiting device can be reduced in size and weight, and the snow carrying ability of the auger can be improved, and the right and left weight balance of the snow removing device can be improved.

According to the configuration of the second aspect, the opening pressure due to excessive torque can be easily changed by adjusting the set pressure of the relief valve. According to the configuration of claim 3,
Since it is determined that a predetermined torque difference has occurred by detecting that there is a difference between the rotational speeds of the driving side and the driven side, it is possible to reliably detect the occurrence of excessive torque. Further, the structure of the detecting means can be simplified and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing an essential part of an embodiment of an auger drive mechanism of the present invention.

FIG. 2 is a sectional view showing a configuration of a hydraulic clutch used for the auger drive mechanism.

FIG. 3 is a circuit diagram showing an electric and hydraulic circuit configuration in the auger drive mechanism.

FIG. 4 is a front view of a general rotary snowplow.

FIG. 5 is an explanatory view showing an auger drive mechanism of the rotary snowplow.

[Explanation of symbols]

 3 Auger 9 Chain Transmission 20 Torque Limiter 21 Drive Shaft 22 Follower Shaft (Auger Shaft) 23 Hydraulic Clutch 25 Clutch Plate 30 Hydraulic Pump 31, 32, 33 Solenoid Valve 35 Drain Tank 36a, b Pressure Switch 37 Relief Valve 38 Accumulator 41 Controller 42 Pressure supply switch 43 Disconnection switch 45, 46 Rotation sensor

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoki Tanimoto 6-107, Kamishino-cho, Shino-cho, Kita-ku, Sapporo, Hokkaido (72) Inventor Go Yamamoto 15-17, Katsuraoka-cho, Otaru-shi, Hokkaido (72) Inventor Kenichi Sato 3-16, Miharucho, Otaru-shi, Hokkaido (72) Inventor Mitaka Hiraga 3-18-16, Hanazono, Otaru-shi, Hokkaido (58) Field surveyed (Int. Cl. ⁶ , DB name) E01H 5/09

Claims (3)

(57) [Claims] 1. An auger drive mechanism for a rotary snowplow having a torque limiting device between a driven shaft on which an auger is mounted and a drive shaft for driving the auger, wherein a hydraulic clutch is used as the torque limiting device. A hydraulically operable hydraulic supply switching valve for switching between supply and cutoff of the hydraulic pressure to the hydraulic circuit, a relief valve for setting the hydraulic pressure of the circuit, and holding of the hydraulic pressure supplied to the circuit. Control means for controlling a switching operation of the two switching valves, a control means for controlling a switching operation of the two switching valves, an instruction means for instructing the control means to supply a hydraulic pressure to the hydraulic circuit, Detecting means for detecting that a predetermined torque difference has occurred between the drive shaft and the driven shaft of the auger; and the detecting means has detected that a predetermined torque difference has occurred between the drive shaft and the driven shaft of the auger. Detect The control means switches the hydraulic pressure holding switching valve to a hydraulic pressure release position based on a signal from the detecting means, and if there is an instruction from the instruction means, the control means switches the hydraulic pressure holding switching valve. An auger drive mechanism for switching a hydraulic pressure supply position to a hydraulic pressure holding position and switching the hydraulic pressure supply switching valve to a hydraulic pressure supply position. 2. The auger drive mechanism according to claim 1, wherein the on-off pressure of the hydraulic clutch is adjusted by adjusting the pressure of the relief valve, and the opening torque of the torque limiting device is set. 3. The apparatus according to claim 1, wherein said detecting means includes a rotation number detecting means for detecting a rotation number of a drive shaft of said auger and a rotation number detecting means for detecting a rotation number of a driven shaft. 2. The auger drive mechanism according to claim 1, wherein a predetermined torque difference is generated when the number is different.