JPS6226580Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to an improvement of a control circuit that controls a cooling fan using an electromagnetic clutch. Cooling fans are used in automobile engines and the like to cool cooling water and the engine body. And this cooling fan is
In the past, cooling fans were generally connected to the crankshaft at all times, but due to energy saving concerns, electromagnetic clutch type cooling fans, which are connected via an electromagnetic clutch, are becoming mainstream. This electromagnetic clutch type cooling fan has a V-belt attached to a drive shaft 12 of a water pump 11, as shown in FIG.
A rotor 14 is connected to the crankshaft via a rotor 14, a cooling fan mounting housing 16 is rotatably supported on the rotor 14 via a bearing device 15, and a main electromagnetic coil 18 is attached to the housing 17 of the water pump 11. At the same time, the armature disk 19 facing the rotor 14 is attached to the cooling fan mounting housing 16 so that the armature disk 19 and the rotor 14 can be electromagnetically engaged and detached. It has a structure in which a sub-armature disk 20 is provided on the outer periphery, and a sub-electromagnetic coil 22 is attached to a bracket 21 of the water pump housing 17 opposite to the sub-armature disk 20. The electromagnetic clutch type cooling fan constructed in this manner is controlled by, for example, a control circuit shown in FIG. That is, in the figure, reference numeral 1 denotes a water temperature switch provided in the cooling water passage, which is normally open and closed when the temperature reaches a predetermined temperature or higher. 2 is a relay whose excitation coil 2a is connected via the water temperature switch 1 between the power supply +V and ground. 1
Reference numeral 8 denotes a main electromagnetic coil of the electromagnetic clutch type cooling fan, which is connected between the power supply +V and the ground via the normal cross contact 2b of the relay 2. Reference numeral 22 denotes a sub-electromagnetic coil of the electromagnetic clutch type cooling fan, which is connected between the power supply +V and the ground via the normally open contact 2c of the relay 2. In the control circuit configured as described above, when the temperature of the cooling water rises above a specified value, the water temperature switch 1 is closed and the exciting coil 2a is excited by the power supply +V. When the exciting coil 2a is excited, the relay 2 switches its contacts 2b and 2c to contact 2.
Only b is closed. When the contact 2b is closed, the power +V flows through the contact 2b to the main electromagnetic coil 18, so the main electromagnetic clutch is operated and the cooling fan is forcibly rotated together with the rotor 14 shown in FIG. Cooling water is cooled by strong winds. When the temperature of the cooling water is cooled to a predetermined temperature or lower, the water temperature switch 1 is turned on.
is opened, the excitation to the excitation coil 2a is released, and the contacts 2b and 2c of the relay 2 are restored to the state shown in the figure. As a result, the main electromagnetic coil 18 is de-energized and the sub-electromagnetic coil 22 is excited. When the sub electromagnetic coil 22 is excited,
The sub-electromagnetic clutch operates to fix the cooling fan mounting housing 16 to the water pump housing 17 side, thereby restraining the slip rotation of the cooling fan and preventing the cooling water temperature from dropping further. However, the electromagnetic clutch type cooling fan control circuit described above uses a water temperature switch 1 that detects the temperature of the cooling water to control the relay 2 on and off, and the contacts of the relay 2 are used to control the main electromagnetic coil 18 and the sub. By driving the electromagnetic coil 22 in reverse, the rotation of the cooling fan is always stopped when the water temperature is low. Therefore, when the cooling water temperature is low and the engine speed is high, Therefore, in order to stop the cooling fan without slipping, a large sub-electromagnetic coil 22 and sub-armature disk 20 are required, which poses a big problem in terms of space and cost. This idea was proposed to solve the above-mentioned conventional problems, and the sub-electromagnetic coil is energized only when the cooling water temperature is below a predetermined value and when the engine is running at low speeds. This is to stop the cooling fan. Hereinafter, the control circuit for an electromagnetic clutch type cooling fan according to this invention will be explained in detail with reference to the drawings. FIG. 3 is a circuit diagram showing an embodiment of the control circuit for an electromagnetic clutch type cooling fan according to this invention, and the same parts as in FIG. 2 are designated by the same reference numerals. In the figure, 5 is an engine rotation state detection switch that opens when the engine rotation speed rises above a predetermined value, and is connected between the contact 2c of the relay 2 and the sub-excitation coil 22. There is. The difference from FIG. 2 is that this engine rotation state detection switch 5 is provided. In the electromagnetic clutch type cooling fan control circuit configured as described above, when the temperature of the cooling water is high, the water temperature switch 1 is closed, and the excitation coil 2a of the relay 2 is energized accordingly. By switching the contacts 2b and 2c, the main electromagnetic coil 18 is excited and the cooling fan is forcibly rotated. When the temperature of the cooling water drops below the reference value, the water temperature switch 1 is opened and the relay 2 is restored, and along with this, the main electromagnetic coil 1
8 is de-energized, and the power +V is output from the contact 2c. In this case, if the engine rotational speed is below a predetermined rotational speed, the engine rotational state detection switch 5 is closed, the sub excitation coil 22 is excited, and the rotation of the cooling fan is stopped. The sub excitation coil 22 is relatively small and has low power. On the other hand, when the engine rotation increases while the cooling water temperature remains below the reference value, the engine rotation state detection switch 5 is opened, and along with this, the sub-excitation coil 22 is de-energized and the cooling fan is in a free state. Become. In this case, even if the cooling fan rotates due to running wind or rotational friction and the cooling water becomes even colder, the combustion stability of the engine will not be impaired because the engine speed is high. The relationship between the main and sub electromagnetic coils 18, 22, cooling water temperature, and engine operating conditions in each of the above cases is shown in the following table.

[Table] Therefore, in the electromagnetic clutch type cooling fan configured in this way, the sub-excitation coil 22 is de-energized when the engine rotates at high speed, which requires a strong stopping force. This prevents the subclutch system from increasing in size. FIG. 4 is a circuit diagram showing another embodiment of this invention, and the difference from FIG. 3 is that a speedometer switch 6 is used as the engine rotation state detection switch 5. And in this case,
Switch 6 installed on the speedometer is
It is turned on when the vehicle speed is below a predetermined speed value.
When the temperature rises above the set value, the switch 6 is opened and the sub-excitation coil 22 is de-energized, thereby freeing the cooling fan. FIG. 5 is a circuit diagram showing still another embodiment, and the difference from FIG. 3 is that an accelerator switch 7 is used in place of the engine rotation state detection switch. In the circuit configured in this way, when the foot is off the accelerator, the lever 8 is biased by the spring.
presses the accelerator switch 7 and closes it. Therefore, in this state, the sub electromagnetic coil 22
is excited and the cooling fan is stopped. Next, when the accelerator pedal is engaged, the accelerator wire 9 is retracted and the lever 8 is rotated. As a result, the lever 8 is rotated and the accelerator switch 7 is opened, and along with this, the sub-electromagnetic coil 22 is de-energized and the cooling fan becomes free. As explained above, the electromagnetic clutch type cooling fan control circuit according to this invention is equipped with an engine rotation state detection switch that detects the low rotation state of the engine, and the sub-electromagnetic coil is activated only when the engine rotation is low and the cooling water temperature is low. Since it controls the cooling fan, less electromagnetic force is required to stop the cooling fan, and the sub-electromagnetic clutch system can be made smaller and lower in cost.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts of an electromagnetic clutch type cooling fan. FIG. 2 is a circuit diagram showing an example of a conventional electromagnetic clutch type cooling fan control circuit, and FIG. 3 is a circuit diagram showing an example of an electromagnetic clutch type cooling fan control circuit according to this invention.
FIGS. 4 and 5 are circuit diagrams showing other embodiments. 1...Water temperature switch, 2...Relay, 2a...
Excitation coil, 2b, 2c... Contact, 5... Engine rotation state detection switch, 6... Speed meter, 7... Accelerator switch, 8... Lever, 9
...Accelerator wire.

Claims (1)

[Scope of utility model registration request] A means for detecting engine cooling water temperature, a main electromagnetic clutch that connects the cooling fan to the drive shaft when the cooling water temperature is higher than a set value, and a sub-electromagnetic clutch that is energized in a reverse action to the main electromagnetic clutch to control and stop the cooling fan. A control circuit for a cooling fan, comprising a clutch, means for detecting engine speed and vehicle speed, and means for preventing excitation of a sub-electromagnetic clutch when engine speed and vehicle speed exceed set values.