JPS6052289B2 - Cooling fan drive device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive device used for a cooling fan that supplies air to a radiator.

Cooling fans for automobiles are classified into three types depending on the driving method: - electric fan, electric fan, electric fan, and electric fan.

The requirements for cooling fans include securing the necessary air volume during cooling, low noise, and low horsepower loss. Direct-coupled fans have the disadvantage of increased noise and horsepower loss, and electric fans and fluid-coupled fans have the disadvantage that it is difficult to ensure maximum airflow. An electromagnetic clutch fan operates in response to the cooling water temperature, and when operating, it can obtain the same air volume as a direct-coupled fan, so it is effective both in terms of reducing drive noise and horsepower loss, and ensuring the required air volume. preferable. The advantages of such an electromagnetic clutch fan are fully demonstrated when the engine compartment is located at the front of the vehicle and the radiator can fully utilize the running wind, but when the radiator is located under the seat. In cab-over type vehicles,
It is difficult to properly utilize the running wind, which results in longer operating times of the electromagnetic clutch fan, increased noise and horsepower loss. Furthermore, the engagement and disengagement of the electromagnetic clutch causes driving noise, and the load and release associated with engagement and disengagement.
Fluctuations can also cause shocks in moving vehicles, so
The use of an electromagnetic clutch fan is particularly undesirable in cab-over type vehicles where engagement and disengagement operations are frequent.
An object of the present invention is to provide a cooling fan drive device that can effectively reduce noise and horsepower loss and ensure the required air volume, especially in cab-over vehicles.

To achieve this object, the cooling fan drive device of the present invention includes a drive shaft driven by the crankshaft of an engine, and a cooling fan as a driven member provided coaxially with the drive shaft. , a fluid coupling that connects the drive shaft and the cooling fan, and an electromagnetic clutch that is provided in parallel to the fluid coupling. A part of the path includes a housing that is supported and receives power from the rotor through the working fluid, a cover that is placed over the housing and defines a housing space for the rotor together with the housing, and a power transmission section from the rotor to the housing using the working fluid. a bimetal having a working fluid circulation path and an opening/closing member that opens and closes the circulation path, further operating the opening/closing member to open the circulation path when the temperature of the cooling air at the front of the cover reaches a first predetermined value or more; An electromagnetic clutch control means is provided that engages the electromagnetic clutch when the engine cooling water temperature reaches a second predetermined value higher than the first predetermined value. Next, embodiments of the present invention will be described with reference to the drawings. o A drive shaft 1 as a drive member is connected to a pulley 4 via a member 2 and a clutch casing 3.

The pulley 4 receives power from the engine crankshaft via a belt, and is connected to a drive shaft 1, a member 2, and a clutch casing 3.
, and the pulley 4 rotate together. Electromagnetic clutch 5
The coil 6 is arranged on one side with respect to the end surface of the clutch casing 3. The coil 6 is fixed to the water pump casing. The water pump casing 7 is attached to the engine's water jacket (not shown). The drive shaft 1 drives a water pump (not shown) in the water casing 7.゛Fluid coupling 1
1 drive rotor 12 is coupled to the drive shaft 1 , and a coupling housing 13 powered by working fluid from the drive rotor 12 is provided concentrically with respect to the drive shaft 1 via a bearing 14 . There is.

The coupling housing 13 is fixed to a housing cover 16 as a driven member by bolts 15. Fan 17 is integrally attached to coupling housing 13 and housing cover 16 by bolts 18.

The leaf spring 21 has an outer edge fixed to the coupling housing 13.

An annular clutch plate 22 of the electromagnetic clutch 5 is disposed on the other side of the end surface of the clutch casing 3 from the coil 6, and is fixed to the inner peripheral portion of the leaf spring 21. The circular partition plate 24 is fixed to the housing cover 16 at its outer edge and has holes 25 at predetermined positions in the radial direction. The control plate 26 is arranged adjacent to the partition plate 24 so as to be rotatable relative to the partition plate 24 by a predetermined amount, and functions as an opening/closing member that opens and closes the hole 25 of the partition plate 24 . The control plate 26 is connected to a control rod 27, and an oil seal 28 is provided between the housing cover 16 and the control rod 27 together with a bearing. The control rod 27 has a spiral bimetal 29
One end of the is attached. The other end of the bimetal 29 is coupled to the housing cover 16. When the control plate 26 opens the hole 25 of the partition plate 24, the fluid in the brute server 32, which is a space defined by the partition plate 24 and the inner wall of the housing cover 16, flows through the hole 2.
5 and through holes 33 in the drive rotor 12 to passages 34 between the respective vanes of the drive rotor 12 and the coupling housing 13 and further to the housing cover 16.
It returns to the brute server 32 again via the path 35 of .

A cooling fan that supplies air to the radiator is attached to the housing cover 16.

The coil 6 is connected via a terminal 37 to a cooling water temperature switch 38 and a driver's seat key switch 3 as shown in FIG.
9 and a storage battery 40.

The operation of this embodiment will be explained with reference to FIGS. 3 to 6.

In FIGS. 3 and 4, the horizontal axis represents the rotational speed A of the drive shaft 1, and the vertical axis represents the rotational speed B (corresponding to the cooling air volume) of the housing cover 16, that is, the cooling fan. In FIG. 3, the solid line a represents the relationship when the electromagnetic clutch 5 is engaged, and the broken line b represents the relationship when the electromagnetic clutch 5 is disengaged and the temperature of the cooling air is a predetermined value T1, for example, 6 (generations) or higher. show. In FIG. 4, the broken line b corresponds to the broken line b in FIG. 3, and the dashed line c shows the relationship when the electromagnetic clutch 5 is in the released state and the temperature of the cooling air is below the predetermined value T1. FIG. 5 shows the relationship between the cooling water temperature c and the operating state of the electromagnetic clutch 5. Figure 6 shows the cooling air temperature D
The relationship between and the flow cross-sectional area E of the hole 25 of the partition plate 24 is shown.
If the engine cooling water temperature c has not yet reached a predetermined value T3, for example 95°C, the cooling water temperature switch 38 is open, the coil 6 does not generate any magnetic force, and the clutch plate 22 is activated by the leaf spring 21. It is away from the end face of the casing 3. In this case, the temperature of the cooling air is set to a predetermined value T1.
The explanation will be divided into cases where the value is less than or equal to the value and cases where the value is greater than or equal to the value.
When the temperature D of the cooling air is below the predetermined value T, the bimetal 29 is contracted, and the control rod 27 and the control plate 26 are in a predetermined position with respect to the partition plate 24 coupled to the housing cover 16. .

That is, the control plate 26 closes the hole 25 of the partition plate 24 (FIG. 6). Therefore, the fluid in the fluid coupling 11 remains stored in the brute server 32 and is prevented from circulating. In this way, almost no rotation of the drive shaft 1 is transmitted to the coupling housing 13. However, due to a small amount of fluid that cannot return to the brute server 32 and remains in the passage 34 and a predetermined frictional resistance in the bearing 14, the rotational speed B of the cooling fan does not become zero, and the rotational speed of the drive shaft 1 A changes as shown by the one-dot chain line c in FIG. The rotational speed of the cooling fan at this time is extremely low. When the temperature D of the cooling air is equal to or higher than the predetermined value T1, the bimetal 29 extends and rotates the control rod 27.

In this way, the control plate 26 rotates relative to the partition plate 24, and the flow cross-sectional area E of the hole 25 becomes maximum as shown in FIG. Therefore, the working fluid circulates through the oil reservoir 32, the holes 25, 33, and the passages 34, 35, and effective operation of the fluid coupling 11 is achieved. In this way, the relationship shown by the broken line b in FIGS. 3 and 4 is obtained. When the coolant temperature reaches a very high temperature, that is, a predetermined value T3 or higher, the coolant temperature switch 38 is automatically closed, and an energizing current is supplied to the coil 6 of the electromagnetic clutch 5. In this way, a magnetic path as shown by the dashed line 41 in FIG. 1 is formed, and the clutch plate 22 engages with the end surface of the clutch casing 3 against the leaf spring 21. That is, the drive shaft 1 and the coupling housing 13 rotate integrally. Therefore, a relationship as shown by solid line a in FIG. 3 is obtained. The rotational speed of the cooling fan in this case is extremely high. The cooling water temperature switch 38 has hysteresis as shown in FIG. 5, and changes from opening to closing at a predetermined temperature T3.
However, the switch from closed to open occurs at a predetermined temperature T2 lower than the predetermined temperature T3 and higher than the above-mentioned predetermined temperature T1, for example, 85°C.

That is, once the electromagnetic clutch 5 is engaged and the coolant temperature c becomes equal to or lower than the predetermined value T2, the coolant temperature switch 38 is opened and the electromagnetic clutch 5 is released. Note that the key switch 39 in FIG. 2 can be omitted.

As described above, according to the present invention, the fluid coupling and the electromagnetic clutch are provided in parallel with each other between the drive shaft and the cooling fan as the driven member.

In the case of power transmission via a fluid coupling, the rotation speed of the cooling fan in the fluid coupling is lower than the rotation speed of the drive shaft, and in the case of power transmission via an electromagnetic clutch, the rotation speed of the cooling fan is equal to the rotation speed of the drive shaft. be equal. Therefore, under normal engine high temperatures, when the temperature of the cooling air at the bimetallic location is above the first predetermined value and the temperature of the engine cooling water is below the second predetermined value, the drive shaft is By transmitting power to the cooling fan, it is possible to avoid an increase in drive noise and horsepower loss, and at times when the engine is abnormally high, such as when the engine cooling water temperature exceeds the second predetermined value, the electromagnetic By transmitting the power of the drive shaft to the cooling fan via the clutch, a high rotational speed of the cooling fan can be ensured. In the present invention, the circulation of the working fluid in the fluid coupling is controlled in relation to the temperature of the cooling air by the operation of the bimetal, and two power transmission characteristics can be obtained in the fluid coupling by performing and blocking the circulation.

Therefore, when the cooling air temperature is low, the power is transmitted to the cooling fan using the lower power transmission characteristic of the fluid coupling, which rotates the cooling fan at a lower rotation speed to reduce noise and horsepower loss. At the same time, warm-up performance can be improved. Furthermore, when the temperature of the cooling air is high, by transmitting power to the cooling fan using the higher power transmission characteristic, the cooling fan can be rotated at a high rotational speed and an appropriate cooling effect can be obtained.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment in which the present invention is applied to a cooling fan coupling device, Fig. 2 is a control circuit diagram of the electromagnetic clutch shown in Fig. 1, and Fig. 3 is a diagram showing a control circuit for the electromagnetic clutch shown in Fig. Figure 4 is a graph showing the relationship between the rotational speed of the drive shaft and the rotational speed of the cooling fan. FIG. 5 is a diagram showing the relationship between the engine cooling water temperature and the operation of the electromagnetic clutch, and FIG. 6 is a diagram showing the relationship between the cooling air temperature and the flow cross-sectional area of the passage for the working fluid of the fluid coupling. 1... Drive shaft, 5... Electromagnetic clutch,
11... Fluid coupling, 12... Drive rotor, 1
3... Coupling housing, 16...
... Housing cover, 17 ... Fan, 26
...Control board, 29...Bimetal.

Claims (1)

[Claims] 1. A drive shaft driven by the engine crankshaft, a cooling fan as a driven member provided coaxially with the drive shaft, a fluid coupling that connects the drive shaft and the cooling fan, and a fluid coupling. The fluid coupling includes a rotor that rotates integrally with the drive shaft, a housing that is rotatably supported by the drive shaft and receives power from the rotor via working fluid, and the housing. A cover that is placed over the housing and defines a rotor accommodation space together with the housing, a working fluid circulation path that includes a part of the path that transmits power from the rotor to the housing by the working fluid, and an opening/closing member that opens and closes the circulation path, Furthermore, when the temperature of the cooling air at the front of the cover reaches a first predetermined value or more, the opening/closing member is operated to open the circulation path, and the temperature of the bimetal and engine cooling water exceeds a second predetermined value which is higher than the first predetermined value. 1. A cooling fan drive device, comprising: electromagnetic clutch control means for bringing an electromagnetic clutch into a connected state when