JP2009092046A - Regular and reverse rotation change over mechanism of cooling fan for construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration of power transmission belt and drop of power transmission efficiency, inhibit cost increase, and save a space, in a construction enabling regular and reverse rotation change-over of a cooling fan. <P>SOLUTION: This mechanism has a regular rotation and a reverse rotation fan pulleys 4, 5 rotatably installed on a shaft of a cooling fan 1, and is provided with a regular rotation power transmission belt 9 transmitting rotation of an output shaft 8 of the engine to the regular rotation fan pulley 4, an idler pulley 12 pressed and made contact on an outside of the regular rotation power transmission belt 9 and rotating in a direction reverse to a drive pulley 7, a reverse rotation pulley 14 rotating as one unit with the idler pulley 12, and a reverse rotation power transmission belt 15 transmitting rotation of the reverse rotation pulley 14 to the reverse rotation fan pulley 5. The mechanism is provided with a clutch 6 transmitting rotation of either of the regular rotation and the reverse rotation fan pulleys 4, 5 to a shaft 2 of the cooling fan 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention belongs to the technical field of a forward / reverse switching mechanism for a cooling fan in a construction machine such as a hydraulic excavator.

Generally, construction machines such as hydraulic excavators are equipped with various cooling devices such as radiators, oil coolers, air conditioner condensers, and aftercoolers, and cooling fans that supply cooling air to the cooling devices on the engine output shaft. Are connected. By the way, construction machines often operate in the field where earth and sand, dust and the like are scattered, and for this reason, the fins and screens of the cooling device are likely to be clogged early due to adhesion and accumulation of dirt and dust. , Frequent cleaning is required. However, it may be difficult to manually perform cleaning work, or it may be difficult to access the cooling device if multiple cooling devices are installed in parallel or if the cooling device is installed in a deep location in the fuselage. .
Therefore, the rotation direction of the cooling fan is configured to be able to rotate in the direction opposite to the normal cooling operation, and the rotation of the cooling fan in the reverse direction blows away dust or dirt adhering to the cooling device. There is something that was made. Conventionally, the engine rotation can be transmitted to the cooling fan shaft by switching the engine rotation between forward and reverse (see, for example, Patent Document 1), and a hydraulic motor for driving the cooling fan is provided. There is known a configuration in which a cooling fan is rotated in forward and reverse directions by controlling the hydraulic motor in forward and reverse directions (see, for example, Patent Document 2).
Japanese Utility Model Publication No. 58-22969 JP-A-10-68142

By the way, in Patent Document 1, when the engine rotation is switched between forward and reverse and transmitted to the cooling fan, the engine rotation is reversely rotated by the cross belt and transmitted to the reverse transmission belt, and the forward rotation transmission that is loosely passed is transmitted. The tension roller is selectively brought into pressure contact with either the belt or the reverse transmission belt, so that the rotation of the forward transmission belt or the reverse transmission belt is transmitted to the cooling fan. However, the cross belt has a problem that it is inferior in durability because the cross belt is wound around in a twisted state. In addition, each time the forward / reverse operation is switched, the tension of the forward / reverse transmission belt is greatly changed to easily cause excessive tension or slip, which causes belt deterioration and reduced transmission efficiency.
On the other hand, a device provided with a hydraulic motor for driving a cooling fan as in Patent Document 2 requires a dedicated hydraulic motor, switching valve, hydraulic piping, etc., and is a small model that requires cost reduction and space saving. There is a problem that the present invention is not suitable, and there is a problem to be solved by the present invention.

  The present invention was created in view of the above-described circumstances to solve these problems. The invention of claim 1 includes a forward fan pulley and a reverse fan pulley on the shaft of a cooling fan. A forward transmission belt wound around a drive pulley that rotates integrally with the output shaft of the engine and the forward fan pulley and that transmits the rotation of the drive pulley to the forward fan pulley, An idler pulley that presses against the outside of the forward transmission belt and rotates in the opposite direction to the drive pulley, a reverse pulley that rotates integrally with the idler pulley, and a winding between the reverse pulley and the reverse fan pulley. A reverse rotation transmission belt that is rotated to transmit rotation of the reverse rotation pulley to the reverse rotation fan pulley, and one of the forward rotation fan pulley and the reverse rotation fan pulley. Providing the clutch for transmitting rotation to the shaft of the cooling fan is a normal and reverse rotation switching mechanism of the cooling fan in the construction machine according to claim.

  With the invention of claim 1, the rotation direction of the cooling fan can be switched between forward and reverse, and thus the cooling fan is rotated in the direction opposite to that in the case of performing normal cooling operation. Although it can remove dust and dirt that has adhered and accumulated, the tension of the forward transmission belt and the reverse transmission belt does not change at all when switching the rotation direction of the cooling fan. There is no risk of excessive tension or slipping due to the switching, and therefore it is possible to reliably avoid the occurrence of problems such as early deterioration of the forward and reverse transmission belts and reduction in transmission efficiency. Moreover, this forward / reverse switching mechanism has a simple and inexpensive structure, does not require a large space, and can contribute to cost reduction and space saving.

  Next, embodiments of the present invention will be described with reference to the drawings. In the figure, reference numeral 1 denotes a cooling fan provided in a construction machine such as a hydraulic excavator, and a cooling device such as a radiator, an oil cooler, an air conditioner condenser, and an after cooler (not shown) is cooled by the cooling air sucked by the cooling fan 1. However, the shaft 2 of the cooling fan 1 is rotatably supported by the engine cover 3.

  Further, a forward rotation fan pulley 4 and a reverse rotation fan pulley 5 are rotatably mounted on the shaft 2 of the cooling fan 1 via bearings 4a and 5a, respectively. An electromagnetic clutch 6 is disposed between the fan pulley 5 for use.

  The electromagnetic clutch 6 is fitted in a spline groove 2a formed on the outer peripheral surface of the shaft 2 so as to be movable in the axial direction, and rotates integrally with the shaft 2 and the direction of the current applied to the solenoid 6a. Accordingly, the forward rotation position moves to the forward rotation fan pulley 4 side and rotates integrally with the forward rotation fan pulley 4, and the reverse rotation side moves to the reverse rotation fan pulley 5 side and rotates integrally with the reverse rotation fan pulley 5. It can be displaced to the position. Thus, in a state where the electromagnetic clutch 6 is located at the forward rotation side position, the rotation of the forward rotation fan pulley 4 is transmitted to the shaft 2 via the electromagnetic clutch 6, while the electromagnetic clutch 6 is moved to the reverse rotation side position. In the position, the rotation of the reverse fan pulley 5 is transmitted to the shaft 2 via the electromagnetic clutch 6.

On the other hand, 7 is a drive pulley (crank pulley) that is attached to the output shaft 8 of the engine and rotates integrally with the output shaft 8. Between the drive pulley 7 and the forward fan pulley 4, there is a forward pulley. A transmission belt 9 is wound. Thus, the rotation of the drive pulley 7 that rotates integrally with the output shaft 8 is transmitted to the forward rotation fan pulley 4 via the forward rotation transmission belt 9. Then, the rotation of the forward rotation fan pulley 4 is transmitted to the shaft 2 of the cooling fan 1 via the electromagnetic clutch 6 at the forward rotation side position, whereby the cooling fan 1 rotates forward and sucks cooling air, It is configured to cool a cooling device such as a radiator or an oil cooler.
In the figure, reference numeral 10 denotes an alternator pulley which is attached to the drive shaft 11a of the alternator 11 and rotates integrally with the drive shaft 11a. Thus, the rotation of the output shaft 8 of the engine is transmitted to the drive shaft 11a of the alternator 11 via the drive pulley 7, the forward transmission belt 9, and the alternator pulley 10.

  Reference numeral 12 denotes an Andorra pulley that presses against the outside of the forward transmission belt 9 and rotates in a direction opposite to that of the drive pulley 7. A support shaft 13 that supports the Andra pulley 12 is rotatable on the engine cover 3. A reverse pulley 14 that rotates integrally with the idler pulley 12 is attached to the support shaft 13.

  Further, a reverse transmission belt 15 is wound between the reverse pulley 14 and the reverse fan pulley 5. Accordingly, the rotation of the reverse rotation pulley 14, that is, the rotation in the direction opposite to that of the drive pulley 7 is transmitted to the reverse rotation fan pulley 5 via the reverse rotation transmission belt 15. Then, the rotation of the reverse rotation fan pulley 5 is transmitted to the shaft 2 of the cooling fan 1 via the electromagnetic clutch 6 at the reverse rotation side position, whereby the cooling fan 1 rotates in the reverse direction, and the radiator, oil cooler, etc. It is configured to blow off dirt, dust, and the like that have adhered to and accumulated on the fins and screen of the cooling device.

  In the present embodiment configured as described, the forward rotation fan pulley 4 and the reverse rotation fan pulley 5 are rotatably mounted on the shaft 2 of the cooling fan 1, and the forward rotation fan pulley 4 has an engine output. The rotation of the drive pulley 7 that rotates integrally with the shaft 8 is transmitted through the forward transmission belt 9, while the reverse rotation fan pulley 5 is pressed against the outside of the forward transmission belt 9 and is opposite to the drive pulley 7. The rotation of the idler pulley 12 that rotates in the direction is transmitted through the reverse pulley 14 and the reverse transmission belt 15 that rotate together with the idler pulley 12. Thus, the normal rotation fan pulley 4 and the reverse rotation fan pulley 5 rotate in the opposite direction, and the rotation of either the normal rotation fan pulley 4 or the reverse rotation fan pulley 5 is the normal rotation side. When the rotation of the forward rotation fan pulley 4 is transmitted to the shaft 2 of the cooling fan 1 through the electromagnetic clutch 6 at the position and the reverse rotation side position, the cooling fan 1 rotates in the forward direction and the radiator and oil While the normal cooling operation for cooling the cooling device such as a cooler is performed, when the rotation of the reverse rotation fan pulley 5 is transmitted, the cooling fan 1 rotates in the reverse direction to adhere to and accumulate on the cooling device. Will be blown away.

  As a result, by rotating the cooling fan 1 in the reverse direction to the normal cooling operation, it is possible to remove dirt and dust adhering to and accumulating on the cooling device, thereby eliminating frequent manual cleaning work. However, in this case, when the rotation direction of the cooling fan 1 is switched between forward and reverse, only the electromagnetic clutch 6 moves and the forward transmission belt 9 and the reverse rotation belt are moved. Since the tension of the transmission belt 15 does not change at all, there is no risk of excessive tension or slippage due to forward / reverse switching, and thus the forward and reverse transmission belts 9 and 15 are deteriorated at an early stage or the transmission efficiency is reduced. It is possible to reliably prevent the occurrence of a malfunction that falls.

  In addition, this forward / reverse switching mechanism has a simple and inexpensive structure, does not require a large space, and the arrangement and attachment of equipment members generally provided on the hydraulic excavator 1, such as the drive pulley 9 and the alternator pulley 10. Since there is no need to change the cost, it can greatly contribute to cost reduction and space saving.

Furthermore, this can easily change the rotation speed of the cooling fan 1 during reverse rotation independently of the rotation speed during forward rotation.
That is, when the cooling fan 1 is reversely rotated to blow off dust, dirt, and the like that adheres to and accumulates on the cooling device, the higher the wind speed, that is, the reverse rotation speed of the cooling fan 1, is more effective. The rotational speed at the time of reverse rotation is changed by changing the pulley ratio between the drive pulley 7 and the idler pulley 12 or the pulley ratio between the reverse pulley 14 and the reverse fan pulley 5 with respect to the rotational speed of the output shaft 8 of the engine. The speed can be increased easily. On the other hand, the rotational speed of the cooling fan 1 during normal rotation is determined by the pulley ratio between the drive pulley 7 and the forward rotation fan pulley 4 with respect to the rotational speed of the output shaft 8 of the engine.
Therefore, by appropriately setting each pulley ratio, when performing a normal cooling operation, the rotation speed of the cooling fan 1 during normal rotation is set to a speed suitable for the cooling operation, while adhering to and accumulating on the cooling device. When removing the dirt, dust, and the like, the removal operation can be performed more efficiently by increasing the rotational speed of the cooling fan 1 when the cooling fan 1 is reversely rotated than the rotational speed when the cooling fan 1 is rotating forward.

  Of course, the present invention is not limited to the above-described embodiment. For example, when the idler pulley 10 is disposed, in the above-described embodiment, the drive pulley 7 and the alternator pulley 10 are disposed. It may be arranged between the drive pulley 7 and the forward fan pulley 4 or between the forward fan pulley 4 and the alternator pulley 10. Of course, the present invention is not limited to the hydraulic excavator, and can be applied to various construction machines such as a wheel loader.

It is a front view of a cooling fan forward / reverse switching mechanism. It is a side view of a cooling fan forward / reverse switching mechanism. It is a partial cross section enlarged view of a cooling fan forward / reverse switching mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooling fan 2 Shaft 4 Forward rotation fan pulley 5 Reverse rotation fan pulley 6 Electromagnetic clutch 7 Drive pulley 8 Engine output shaft 9 Forward rotation transmission belt 12 Idler pulley 14 Reverse rotation pulley 15 Reverse rotation transmission belt

Claims (1)

  The forward rotation fan pulley and the reverse rotation fan pulley are rotatably mounted on the cooling fan shaft, and the rotation of the drive pulley is wound between the drive pulley that rotates integrally with the engine output shaft and the forward rotation fan pulley. A forward transmission belt that transmits the forward rotation to the forward rotation pulley, an idler pulley that presses against the outside of the forward transmission belt and rotates in a direction opposite to the drive pulley, and a reverse pulley that rotates integrally with the idler pulley. A reverse transmission belt wound around the reverse pulley and the reverse fan pulley to transmit the rotation of the reverse pulley to the reverse fan pulley, and the forward fan pulley and the reverse fan pulley Forward / reverse switching of the cooling fan in a construction machine, characterized in that a clutch for transmitting either rotation to the cooling fan shaft is provided. Structure.

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