KR20120072522A - Control system for rotational direction of fan - Google Patents

Abstract

PURPOSE: A system for controlling the rotational direction of a fan is provided to prevent construction machines from becoming broken caused by a breakdown in the system. CONSTITUTION: A system for controlling the rotational direction of a fan comprises a fan pump, a flow control valve, a direction control valve, and a controller. A method for controlling the rotational direction of the fan comprises following steps. The speed of a driving fan is reduced at the minimum speed using the flow control valve. The reduced speed of the fan is maintained. The rotational direction of the fan is switched in other direction using the direction control valve. The rotational speed of the fan is accelerated using the flow control valve.

Description

Control system for rotational direction of fan

The present invention relates to a system for controlling the rotational direction of a fan, and more particularly, a system capable of controlling the rotational direction of a cooling fan that is rotationally driven using hydraulic pressure, such as a cooling fan of a construction machine, from forward to reverse or vice versa. It is about.

Construction machinery such as excavators and the like typically include a cooling fan driven by hydraulic pressure as a means for cooling the temperature of the engine room, the coolant, the hydraulic oil and the like, so that the cooling fan can be driven in the forward or reverse direction as necessary. Consists of.

In addition, a fan such as a cooling fan is configured to allow the fan to change the direction of rotation from forward to reverse, or vice versa. In this case, by appropriately reducing the rotation speed of the fan, a direction control valve such as a solenoid valve is used. And to change the rotation direction of the fan.

An example of such a conventional direction control system will be described with reference to FIG. 1.

For example, as shown in FIG. 1, a typical system includes a fan pump 10 for discharging hydraulic oil, a fan motor 40 connected to the fan pump 10 through a hydraulic line, and disposed on the hydraulic line. Flow control valve 50 and directional control valve 60. The fan 30 is connected to the fan motor 40, and the rotation speed and the rotation direction of the fan 30 may be controlled by controlling the flow control valve 50 and the direction control valve 60.

Further, a braking priority valve 20 and a tank 12 are further formed which can be driven to first supply the hydraulic oil discharged from the fan pump 10 to the braking device 22.

In such a system, the procedure of switching the rotational direction of the fan 30 rotating in one direction may be exemplarily described by taking the driving timing of the flow control valve and the direction control valve.

As shown in FIG. 2, the fan rotation speed is reduced by changing the current command applied to the flow control valve over a period of about 2.5 seconds from the MIN value to the MAX value for the fan rotating in one direction, for example, rotating in the reverse direction. do. At the same time as the deceleration is completed, a direction control valve such as a solenoid valve is driven from the ON state to the OFF state to switch the supply direction of the hydraulic oil, whereby the rotational direction of the fan is changed from the reverse direction to the forward direction, for example. At reduced speed, the fan's forward rotation is maintained for a period of about 3 seconds, and then the fan rotates in the forward direction at the proper rotational speed by changing the current command from the MAX value to the appropriate current value over a period of about 2.5 seconds. For example, a suitable current value may be about 50-550 mA.

This procedure allows the fan to switch the direction of rotation from reverse to forward and vice versa from forward to reverse.

At this time, as the switching of the fan rotation direction is repeated, the fan motor may be damaged, the durability of the direction control valve may be degraded, or the construction machine itself may be down due to a failure of the fan rotation direction control system.

In particular, since the fan typically rotates at an appropriate rotational speed based on the temperature of the object to be cooled when rotating in the forward direction, while the fan rotates at the maximum speed when rotating in the reverse direction, the rotation direction is changed from the reverse rotation to the forward rotation. The more likely you are to encounter these problems.

For example, in the current value range (MIN value to MAX value) applied to the flow control valve to control the rotation speed of the fan, the MAX value is used when decelerating the rotation speed, but the rotation speed of the fan controlled by the MAX value Is not a speed slowed down enough to switch the direction of rotation of the fan, which could damage the fan motor.

In addition, since the direction control valve is directly driven in the decelerated state to change the rotation direction, the direction change is performed while the rotational force due to the fan inertia is not sufficiently reduced, so that the durability of the direction control valve could be lowered.

For example, switching from the normal fan rotation speed to the opposite direction can cause problems such as peak pressure in the fan motor 40, which also affects the directional control valves, and adversely affects the fan motor shaft. there was. Accordingly, the fan motor is configured so that the rotational direction is changed at a rotational speed of about 300 rpm or less.

On the other hand, the normal fan pump 10 supplies hydraulic oil to a braking device 22 such as a normal brake, and preferentially supplies hydraulic oil to the braking device 22 rather than the fan pump 40 when the braking device 22 is operated. The braking priority valve 20, which is set to do so, is further connected.

Thus, if a request is made for the brake device 22 while the fan is rotating or the direction of rotation of the fan changes, for example if a pilot pressure to the brake device 22 is detected, the brake priority valve 20 is driven. The hydraulic oil discharged from the fan pump 10 is preferentially supplied toward the braking device 22.

As a result, a phenomenon in which the flow rate of the hydraulic oil supplied to the fan motor 30 is interrupted may occur, which may suddenly stop the rotation of the fan, and may cause damage to components such as the fan motor.

In summary, when the fan rotation direction is switched by the conventional fan rotation direction control system, especially when switching from reverse rotation to forward rotation, the fan motor is damaged, the durability of the direction control valve is deteriorated, or even such Failure of the system could result in the construction equipment itself crashing and becoming inoperable.

In addition, the stopping of the supply of the hydraulic oil discharged from the fan pump during the operation of the braking priority valve may cause problems such as sudden stop of the fan or damage of related components.

An object of the present invention is to provide a rotation direction control system of a fan for preventing the fan motor from being damaged when the fan of the construction machine is switched from reverse rotation to forward rotation.

Another object of the present invention is to provide a rotation direction control system of a fan that can prevent the durability of the direction control valve from deteriorating due to the rotation direction of the fan.

Another object of the present invention is to prevent problems such as the construction machine itself is down due to the failure of the rotation direction control system of the fan.

In order to achieve this object, the present invention includes a fan pump for discharging hydraulic oil; A fan rotating in both directions by a fan motor driven by operating oil; A flow control valve for controlling the rotational speed of the fan motor; A direction control valve for adjusting a direction of the hydraulic oil supplied to the fan motor; And a control unit controlling an operation of the fan pump, the flow control valve, and the directional control valve, wherein the control unit comprises the steps of: a) reducing the speed of the fan rotating in one direction to the lowest speed that can be realized using the flow control valve; Wow; b) maintaining rotation of the fan at a reduced speed; c) switching the rotation direction of the fan to another direction using a direction control valve; And d) accelerating the rotational speed of the fan using a flow control valve, wherein step b) is at least the sum of the time periods required for steps a) and d). It provides a system for controlling the rotation direction of the fan, characterized in that it is kept longer.

Also in the present invention, when the system further includes a braking device and a braking priority valve that preferentially supplies the hydraulic fluid of the fan pump to the braking device over the fan motor, the system is connected in parallel to both ends of the fan motor, An accumulator for filling a part of the hydraulic oil supplied to the fan motor; And a charge control valve which is operated by the controller and controls the charging direction of the accumulator. When the braking priority valve is driven, hydraulic oil is supplied from the accumulator to the fan motor.

In the present invention, the filling control valve is characterized in that it is driven at the same time as the start of step b).

According to the present invention, since the rotational force of the fan due to the inertia can be sufficiently reduced, damage to the fan motor due to the control of the fan rotation direction can be prevented.

Further, according to the present invention, since the rotation direction of the fan is changed after the fan is sufficiently maintained at the minimum speed, the durability of the direction control valve can be prevented from being lowered.

In addition, according to the present invention it is possible to prevent problems such as the down of the construction machine itself by preventing damage to the fan motor and durability of the direction control valve.

1 is a schematic hydraulic circuit diagram showing an example of a system for controlling the rotational direction of a conventional fan;
2 is a view showing an exemplary driving time of the direction control valve and the flow control valve in the conventional fan rotation direction changeover;
3 is a flowchart illustrating a fan rotation direction control procedure according to an embodiment of the present invention;
4 shows an exemplary driving time of the direction control valve and the flow control valve according to the embodiment of FIG. 3;
5 is a hydraulic circuit diagram schematically showing a system for controlling a rotational direction of a fan according to another embodiment of the present invention; And
6 includes an exemplary drive of a fill control valve in accordance with another embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

3 is a flowchart illustrating a change in fan rotation direction according to an embodiment of the present invention, and FIG. 4 is a diagram illustrating an exemplary driving time point of the valves according to the embodiment of FIG. 3. In addition, the system of this embodiment is basically similar to the configuration of FIG. 1, which will be described using reference numerals of FIG.

According to the present invention, the switching of the fan rotation direction starts at step S110 in which the fan is rotating in one direction, for example, in a reverse direction, and decelerates the rotation speed of the fan at the lowest speed which can be realized using the flow control valve 50. Step (S120), maintaining the rotation of the fan at a reduced speed for a predetermined period (S130), and using the direction control valve 60 to change the rotation direction of the fan in another direction, for example, from the reverse direction to the forward direction And step (S140), and using the flow control valve 50 includes the step of accelerating the rotational speed of the fan at an appropriate speed (S150).

For example, step S110 may represent a state in which the fan 30 is rotating in the reverse direction at the maximum speed for about 5 minutes, where 5 minutes is an arbitrary value set for reverse rotation in a general construction machine, and may be freely set. Next, step S120 is to change the control current value applied to the flow control valve 50 from the MIN value to the controller maximum current value over about 2.5 seconds, the controller maximum current value being in the normal control range indicated by the dotted line, in particular A value outside the MAX value, for example, may be about 580 mA as shown in FIG. Thus, the fan can be decelerated to the lowest speed which is lower than the conventional deceleration speed.

Next, step S130 is to maintain the rotation of the fan decelerated at the lowest speed for about 10 seconds, in which the rotational direction of the fan maintains the initial rotational direction, that is, the reverse direction, unlike in the prior art. This means that the rotational force due to the inertia of the fan can be minimized by being maintained for a predetermined period of time, for example, 10 seconds while the fan is decelerated at the lowest speed. In this embodiment, it can be seen that the period of 10 seconds set in step S130 is an arbitrary value and is a period which is increased by more than twice as compared with the conventional 3 seconds. For example, it may be preferable that the sustain period of step S130 is set longer than the sum of the periods required for the previous deceleration step S120 and the subsequent acceleration step S150.

Next, step S140 is to drive a direction control valve 60 such as a solenoid valve to change the rotation direction of the fan. For example, the rotation direction of the fan can be controlled by switching the supply direction of the hydraulic oil supplied to the fan motor 40. Can be. For example, the rotation direction of the fan can be switched from the reverse direction to the forward direction. Unlike the conventional method, since the direction control valve 60 is driven after the minimum speed maintaining step S130 of about 10 seconds, the direction change is performed while the rotational force of the fan due to inertia is minimized, resulting in the direction control valve 60. ) Durability can be prevented.

Finally, step S150 is to accelerate the rotation speed of the fan over about 2.5 seconds. For example, by changing the current value applied to the flow control valve 50 from the controller maximum current value to an appropriate current value, the rotation speed of the fan can be accelerated from the minimum speed to the proper speed.

In the embodiment of the present invention, the control current value applied to the flow control valve to reduce the rotation speed of the fan in switching the rotation direction of the fan is outside the interval range from the MAX value in the conventional control interval range, in particular, the MAX value. By changing the controller to a value outside of the controller, the fan speed can be reduced to the lowest speed.

In addition, it is possible to minimize the rotational force of the fan by inertia by maintaining the rotation of the fan for a period of about 10 seconds longer than conventional, for example, longer than conventional 3 seconds while the fan is decelerated at the lowest speed.

In addition, it is possible to prevent the durability of a directional control valve such as a solenoid valve from deteriorating in a state in which the rotational force of the fan due to inertia is minimized, for example, by changing the rotational direction of the fan after a holding period of about 10 seconds, that is, immediately before the fan is accelerated. Can be.

As such, the present invention is directed to changing the current value applied to slow down the rotational speed of the fan (e.g., the controller maximum value outside the range of the existing control section) and to increasing the holding period at the lowest state after deceleration (e.g., from 3 to 10 seconds). And changing the driving timing of the direction control valve (for example, from the start of the maintenance period to the end of the maintenance period), to prevent damage to the fan motor and deterioration of the durability of the direction control valve. Downtime due to failure of the rotation direction control system can be prevented.

Next, FIG. 5 is a circuit diagram illustrating an example of a fan rotation direction control system according to another embodiment of the present invention, and FIG. 6 is a diagram illustrating a driving time point of each valve.

5 is basically similar to that of FIG. 1, except for the configuration of the accumulator 70 and the charge control valve 72, for example. Details of substantially identical components will be omitted.

For example, as shown in FIG. 5, the system 100 of the present invention includes a fan pump 10 for discharging hydraulic oil, a fan motor 40 connected to the fan pump 10 through a hydraulic line, and the hydraulic line. Flow control valve 50 and directional control valve 60 disposed thereon. The fan 30 is connected to the fan motor 40, and the rotation speed and the rotation direction of the fan 30 may be controlled by controlling the flow control valve 50 and the direction control valve 60. These elements (fan pump, flow control valve, directional control valve, etc.) are controlled by a control unit (not shown).

Further, a braking priority valve 20 and a tank 12 are further formed which can be driven to first supply the hydraulic oil discharged from the fan pump 10 to the braking device 22.

Further, according to the feature of this embodiment, the accumulator 70 which is connected in parallel at both ends of the fan motor 40, and the charge control valve 72 for controlling the filling direction of the hydraulic oil to the accumulator 70 is further added. Include.

In addition, in order to supply hydraulic oil to the accumulator 70 in accordance with the rotational direction of the fan 30, a filling control valve 72 is formed, for example, the filling control valve 72 is a fan as shown in FIG. 6. It is configured to drive when the rotational speed of the fan is decelerated so as to change the rotational direction of the controller, and to control the hydraulic oil supply direction to the accumulator 70.

Thus, even when the rotation direction of the fan is switched, the supply direction of the hydraulic oil to the accumulator 70 is appropriately changed, so that the hydraulic fluid of an appropriate flow rate may be maintained in the accumulator 70 at all times.

As such, the accumulator 70 is configured to fill a part of the hydraulic oil supplied to the fan motor 40 when the fan 30 rotates, for example, the braking priority valve 20 is driven to the fan motor 40. When the hydraulic oil supply of the fan pump 10 is stopped, it is possible to temporarily supply hydraulic oil from the accumulator 70 to the fan motor 40. Therefore, in this embodiment including the accumulator 70, the hydraulic oil can be supplied to the fan pump 40 without interruption even when the braking priority valve 20 is driven.

In addition, the accumulator 70 of the present invention can reduce the moment of inertia of the fan when changing the fan rotation direction, thereby enhancing durability of the overall fan rotation direction control system.

For example, referring to FIG. 5, when the fan 30 rotates in the reverse direction, for example, when the directional control valve 60 is in the ON state, the charge control valve 72 is also driven in the ON state of the accumulator 70. ) Is filled with operating oil, and when the rotation direction of the fan is changed from the reverse direction to the forward direction, the filling control valve 72 is turned OFF so that the flow rate and pressure of the operating oil charged in the accumulator 70 are changed to the fan motor 40. C) can be supplied in the opposite direction, thereby preventing cavitation in which the supply of hydraulic oil to the fan motor is cut off, and also reducing the rotation speed of the fan.

On the contrary, when the fan rotates in the forward direction, for example, when the direction control valve 60 is in the OFF state, the filling control valve 72 is also filled with hydraulic oil while the charge control valve 72 is driven OFF, When the direction of rotation of the fan is reversed from, the charge control valve 72 is switched to the ON state so that the flow rate and pressure of the hydraulic oil charged in the accumulator 70 are also supplied to the fan motor 40 in the opposite direction. Cavitation of the fan motor can be prevented, and the rotation speed of the fan can also be reduced.

Therefore, the drive of the charge control valve 72 to the accumulator 70 is performed before the drive of the direction control valve to control the supply direction of the hydraulic oil to the actual fan motor, thereby reducing the rotational speed of the fan in advance. It is desirable to be configured to contribute. For example, as shown in FIG. 6, the charge control valve 72 may be driven at the beginning of a period during which the fan 30 remains decelerated at the lowest speed, such as a period of about 10 seconds.

As described above, the present invention relates to a system for controlling the rotational direction of the fan, and in particular, the change of the current value applied to the flow control valve, the increase in the time maintained at the minimum speed, and the driving of the direction control valve. By changing the viewpoint, the conventional problems such as damage to the fan motor or deterioration of the durability of the directional control valve can be solved.

In addition, through the additional components including the accumulator, the problem that the flow rate of the hydraulic oil to the fan motor when the braking priority valve is driven can be solved.

While the invention has been particularly shown and described with reference to the preferred embodiments, it will be understood that various modifications and changes may be made by those skilled in the art without departing from the spirit of the invention as set forth in the appended claims.

100: rotation direction control system of the fan
10: fan pump 12: tank
20: braking priority valve 22: braking device
30: fan 40: fan pump
50: flow control valve 60: directional control valve
70: accumulator 72: charge control valve

Claims (3)

A fan pump 10 for discharging hydraulic oil;
A fan 30 rotating in both directions by the fan motor 40 driven through the hydraulic oil;
A flow control valve 50 controlling the rotation speed of the fan motor 40;
A direction control valve 60 for adjusting a direction of the hydraulic oil supplied to the fan motor 40; And
And a control unit for controlling the operation of the fan pump 10, the flow control valve 50, and the direction control valve 60.
a) decelerating the speed of the fan rotating in one direction to the lowest speed possible using the flow control valve 50;
b) maintaining rotation of the fan at the reduced speed;
c) switching the rotation direction of the fan to another direction by using the direction control valve (60); And
d) accelerating the rotational speed of the fan by using the flow control valve (50);
Is configured to perform at least a series of procedures, including
Wherein the step b) is maintained at least longer than the sum of the periods required for steps a) and d). 2. The brake priority valve (20) according to claim 1, wherein the system preferentially supplies hydraulic fluid of the fan pump (10) to the brake device (22) and the fan motor (40) rather than the fan motor (40). When including more
The system includes an accumulator (70) connected in parallel to both ends of the fan motor (40) and filling a portion of the hydraulic oil supplied to the fan motor (40); And
A charge control valve 72 which is operated by the control unit and controls a charging direction of the accumulator 70;
It further comprises, when the braking priority valve (20) is driven, the rotation direction control system of the fan, characterized in that the operating oil is supplied from the accumulator (70) to the fan motor (40). 3. The system of claim 2, wherein the charge control valve (72) is driven simultaneously with the start of step b).

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