JP2001090537A - Water pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify constitution and to reduce a cost in a water pump capable of stopping substantially an operation of the pump when a water temperature is low. SOLUTION: In this water pump 1, a first rotary body 8 with a fixed pulley 7 is connected to a second rotary body 10 with a fixed impeller by a wet type multiple disk clutch 26 using a viscous fluid 33 as a liquid medium, and a heat- sensitive member 38 is provided to be deformed in response to the cooling water temperature so as to carry out connection and release for the clutch 26. Since electric control is not performed, constitution is simplified, a cost is reduced, and accurate control is carried out based on the water temperature. Driving force for transmission is elevated smoothly in response to water temperature rise, and the clutch 26 is directly connected when the water temperature is high.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a water pump applied to a vehicle engine and the like.

[0002]

2. Description of the Related Art Generally, in a water pump of a vehicle engine, a driving pulley is connected to a crank pulley via a belt, and the driving pulley is directly connected to an impeller. Therefore, the discharge amount of the water pump changes almost linearly with respect to the engine speed regardless of the water temperature or the like.

However, when the water temperature is low, the discharge amount of the pump is not required so much to promote warm-up. With the above structure, the pump is driven in accordance with the engine rotation at this time as well, leading to an increase in friction and a deterioration in fuel efficiency.

[0004] To solve this problem, Japanese Utility Model Publication No. 8-2433, Japanese Patent Application Laid-Open No. 10-159874, and Japanese Patent Application Laid-open No.
It is disclosed in Japanese Utility Model Laid-Open No. Sho 60-139028 and Japanese Patent Laid-Open No. Hei 4-214416.

[0005]

In the techniques described in the above and the above,
Driving force is transmitted from the pulley side to the impeller side of the water pump via a fluid coupling (a kind of viscous coupling), and the driving force is shut off by sliding the coupling at low water temperature. With this alone, a sufficient discharge amount cannot be obtained at a high water temperature, and therefore, an electromagnetic clutch is used, and an electrorheological fluid is used, so that the pulley side and the impeller side can be directly connected.

[0006] However, such a configuration that requires electrical control requires a complicated structure and high cost.

[0007] On the other hand, in the techniques (1) and (2), the clutch is connected / disconnected using a bimetal or a shape memory alloy, and the presence / absence of driving force transmission from the pulley side to the impeller side is switched.

However, since the bimetal or the shape memory alloy responds to the outside air, accurate control cannot be performed based on the water temperature, that is, the engine warm-up state. On the other hand, although the shape memory alloy is sensitive to the cooling water, the clutch is rapidly connected because the clutch is a friction clutch or a meshing clutch, and the engine speed drops sharply at that time.

[0009]

SUMMARY OF THE INVENTION A water pump according to the present invention comprises a first rotary member having a fixed pulley and a second rotary member having an impeller fixed therein, which is a wet multiple plate using a viscous fluid as a liquid medium. A temperature-sensitive member is provided which is connected by a clutch and is deformed according to the temperature of the cooling water to connect and disconnect the wet multi-plate clutch.

In the present invention, since the wet multi-plate clutch is connected and disconnected by a temperature-sensitive member such as a thermostat which is sensitive to the cooling water, the structure is simple and the cost is reduced, and accurate control based on the water temperature becomes possible. The transmission driving force can be smoothly increased in accordance with the rise of the water temperature. When the water temperature is high, the clutch is in a directly connected state, and the driving force can be completely transmitted.

The first rotating body is coaxially connected to the outer periphery of the second rotating body so as to be relatively rotatable, and the wet multi-plate clutch is formed in a radial gap between the rotating bodies. An operation in which the first rotating body extends from the clutch pressing member to the cooling water passage through the shaft center of the second rotating body, the clutch pressing member being capable of pressing the wet multi-plate clutch from an end; A shaft, and the temperature-sensitive member is provided at an extended end of the operation shaft, and the operation shaft and the clutch pressing member are moved in the axial direction by deformation of the temperature-sensitive member in a cooling water passage. It is preferable that the wet multi-plate clutch be connected and disconnected.

The wet multi-plate clutch includes a first clutch plate engaged with the first rotating body and a second clutch plate engaged with the second rotating body. Preferably, the thermal expansion coefficients of the second clutch plates are different from each other.

[0013]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a water pump according to the present invention. The water pump 1 is provided on the outer surface of the engine 2 and at a position where the cooling water introduction hole 3 is located. Cooling water introduction hole 3
Is communicated with a cooling water passage 4 inside the engine 2. The cooling water introduction hole 3 and the cooling water passage 4 constitute a part of a cooling water passage of an engine cooling system. The water pump 1 has a pump body 5, and the pump body 5 is attached to the engine 2 with bolts 6 so as to close the cooling water introduction hole 3.

The water pump 1 includes a first rotating body 8 on which a pulley 7 is fixed, and a second rotating body 10 on which an impeller 9 is fixed. The first rotating body 8 is composed of an outer ring 14, and a pulley 7 is integrally formed on the outer peripheral surface thereof. In the figure, the cross section of the pulley 7 is drawn as a straight line, but this can be changed depending on the cross-sectional shape (V shape, waveform, etc.) of the partner belt. The second rotating body 10 includes a pump shaft 12 rotatably supported by a bearing 11 of the pump body 5, and an inner ring 13 fixed to a tip of the pump shaft 12. The impeller 9 is formed by attaching a plurality of blades 16 to a support disk 15 made of sheet metal, and the support disk 15 is formed with a cylindrical portion 17 that is press-fitted and fixed to the base end of the pump shaft 12.

When the impeller 9 rotates, cooling water is introduced from outside in the radial direction, and is discharged to the cooling water introduction hole 3.
A seal portion 18 is provided adjacent to the impeller 9 to prevent leakage of the cooling water. Even if it leaks, it is discharged out of the pump through the drain hole 19 of the pump body 5. The seal portion 18 includes a seal bearing 20 and also supports the pump shaft 12.

The second rotating body 10 configured as described above includes:
The pump body 5 cannot be moved in the axial direction.

The inner ring 13 has a cylindrical portion 21 surrounding the bearing portion 11 from the outside in the radial direction. The outer ring 14 is coaxially mounted on the outer peripheral side of the cylindrical portion 21 via a ball bearing 22 so as to be relatively rotatable. However, the outer ring 14 cannot move relative to the inner ring 13 or the second rotating body 10 in the axial direction. The front end (the left side in the figure is the front) of the outer ring 14 is opened, and the clutch disk 23 (which constitutes the clutch pressing member of the present invention) is inserted into the opening so as to be slidable in the axial direction. The joint between the inner ring 13 and the outer ring 14 and the joint between the outer ring 14 and the clutch disc 23 are sealed by O-rings 24 and 25. Thereby, a closed space is created between the inner ring 13 and the outer ring 14.

The first rotating body 8 and the second rotating body 10 are connected by a wet multi-plate clutch 26. That is, the wet multi-plate clutch 26 is formed in a radial gap formed between the cylindrical portion 21 and the outer ring 14 and on the rear side of the clutch disk 23. The wet multi-plate clutch 26 includes a plurality of first clutch plates 27 (outer plates) engaged with the outer ring 14 and a plurality of second clutch plates 28 (inner plates) engaged with the cylindrical portion 21. It is arranged alternately in the direction. These clutch plates 2
As shown in FIG. 2, the engagement between the outer ring 14 and the cylindrical portion 21 is performed by engagement grooves 29, 30 formed in the clutch plates 27, 28 at four locations at equal intervals in the circumferential direction. And engagement projections 31 and 32 provided on the inner peripheral surface and the outer peripheral surface of the cylindrical portion 21 and extending in the axial direction. The liquid medium of the wet multi-plate clutch 26 is made of a viscous fluid 33 filled in the closed space, for example, silicon oil.

In this wet multi-plate clutch 26, the clutch plates 27 and 28 are brought into close contact with and separated from each other in accordance with the axial movement of the clutch disk 23, and the clutch 26 is connected and disconnected. However, the stroke of the clutch disk 23 at this time is slight. That is, the clearance between the clutch plates 27 and 28 and the clutch disk 23 when the clutch is disconnected is small, and at this time, a slight driving force is transmitted by the drag of the viscous fluid 33.

An operating shaft 34 is connected to the clutch disk 23 to cause the clutch disk 23 to move in the axial direction. The front end of the operating shaft 34 has the clutch disk 23.
And is fixed with a nut 35. The operation shaft 34 extends rearward from the clutch disk 23, passes through the axial center of the pump shaft 12, and extends to the cooling water introduction hole 3. An enlarged hemispherical stopper 36 is integrally formed at the rear end of the operation shaft 34, and a thermostat 38 as a temperature sensing member is provided between the stopper 36 and the rear end surface of the cylindrical portion 17 of the impeller 9. Are attached to the operation shaft 34 by extrapolation.

The thermostat 38 expands and contracts in the axial direction according to the temperature by directly touching the cooling water. In this case, the cylindrical portion 17 of the impeller 9 or the entire second rotating body 10 receives a reaction force (tensile force), and the operation shaft 34 and the clutch disk 23 move integrally in the axial direction.

In the wet multi-plate clutch 26, the first clutch plate 27 and the second clutch plate 28 have different coefficients of thermal expansion. That is, the first clutch plate 27 is made of resin and the second clutch plate 28 is made of metal such as steel, and the former has a larger coefficient of thermal expansion than the latter. The first clutch plate 27 is thicker than the second clutch plate 28 except for the first clutch plate. The first one is equal in thickness to the second clutch plate 28.

Next, the operation will be described.

In the water pump 1, a rotational driving force is transmitted to the pulley 7 from a crank pulley via a belt (not shown). This rotational driving force is appropriately transmitted to the impeller 9 according to the connection / disconnection state of the clutch 26.

When the water temperature is low, for example, immediately after the start of the engine, the thermostat 38 is in a contracted state. Then, the clutch disk 23 is moved (released) to the front side, and the clutch plate 2
7, 28 do not adhere to each other. When this happens, the viscous fluid 33
Only by the drag (shear torque) of the second rotating body 1
In particular, the impeller 9 is driven, the impeller 9 rotates at a low speed, and the pump discharge amount is suppressed. As described above, the operation of the pump can be substantially stopped at the time of low water temperature, so that friction can be reduced and fuel consumption can be prevented from deteriorating.

On the other hand, when the engine warms up and the water temperature rises, the thermostat 38 is extended, and the clutch disk 23 is pulled rearward through the operation shaft 34, and is pushed by the clutch disk 23 so that the clutch plate 2
7, 28 are in close contact with each other. When this occurs, the clutch 26 is completely connected, and all the driving force of the pulley 7 is transmitted to the impeller 9. As a result, a linear pump discharge amount corresponding to the engine speed can be obtained as usual, and normal performance can be satisfied.

As described above, in the present embodiment, the wet type multi-plate clutch 26 is connected to the thermostat 38 which is sensitive to the cooling water.
, Electrical control becomes unnecessary, the configuration is simplified, and the cost is reduced. In addition, accurate control based on the water temperature becomes possible. Since the thermostat 38 expands smoothly as the water temperature rises, the clutch 26 can be smoothly connected according to the rise in the water temperature to increase the transmission torque. When the water temperature is high, the clutch is in a directly connected state, and the driving force can be completely transmitted.

If the engine suddenly blows up at low water temperature, the viscous fluid 33 generates heat due to the differential between the clutch plates 27 and 28, but the temperature rises to high temperature, although the clutch 26 is disengaged. Then, the first clutch plate 27 thermally expands due to this heat, and the second clutch plate 28
, The clutch 26 is engaged, and the impeller 9 is rotationally driven in the same manner as usual, so that a high pump discharge amount can be obtained.

As described above, the thermal expansion coefficients of the first clutch plate 27 and the second clutch plate 28 are made different from each other. In particular, one of the clutch plates (here, the first clutch plate 27) has a relatively large thermal expansion coefficient. Since it is made of a material (here, resin), it can be provided even under low water temperature under conditions that require a pump discharge rate.
It is very advantageous for heat measures. In order to obtain this effect, the clutch plates 27, 2 at low water temperature and when the clutch is disengaged.
The gap between 8 is made as small as possible.

Here, even when the rotation speed is low and the rotation speed is low, the viscous fluid 33 generates heat when the rotation is continued for a long time, and the clutch 26 is connected due to the thermal expansion of the first clutch plate 27. In order to prevent this, it is necessary to extend the thermostat 38 and set the clutch 26 to be connected prior to such connection.

In the present embodiment, since the pulley 7 and the clutch 26 are provided so as to surround the bearing 11 of the pump body 5, it is advantageous for downsizing.

As described above, various other embodiments of the present invention are conceivable. For example, a material having a larger coefficient of thermal expansion than the first clutch plate 27 may be used for the second clutch plate 28, a material having a larger coefficient of thermal expansion may be used for both clutch plates 27, 28, or both clutch plates 27, 28 may be used.
It is conceivable that the combination of the materials of 28 is other than steel and resin, or that the viscous fluid 33 is other than silicon oil. The temperature sensing member may be made of a bimetal, a shape memory alloy, or the like in addition to the thermostat 38.

[0034]

The present invention exhibits the following excellent effects.

(1) The structure is simple and the cost is low.

(2) A high pump discharge rate can be obtained as needed even at a low water temperature, which is advantageous in terms of measures against heat.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1, showing first and second clutch plates.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water pump 3 Cooling water introduction hole 7 Pulley 8 First rotating body 9 Impeller 10 Second rotating body 23 Clutch disk 26 Wet multi-plate clutch 27 First clutch plate 28 Second clutch plate 33 Viscous fluid 34 Operation shaft 38 Thermostat

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16D 13/52 F16D 13/52 A 43/25 43/25 A F term (Reference) 3H020 AA01 BA03 BA06 BA18 BA10 CA10 DA01 DA07 3H022 AA01 BA03 BA06 CA01 CA09 CA12 CA28 CA54 CA58 DA01 DA09 DA20 3H032 AA01 AA07 AA10 3J056 AA33 AA60 AA62 BA04 BE07 CC01 GA01 GA11

Claims (3)

[Claims] 1. A first rotating body having a fixed pulley and a second rotating body having an impeller fixedly connected by a wet multi-plate clutch using a viscous fluid as a liquid medium, and deformed according to the temperature of cooling water. And a temperature-sensitive member for connecting and disconnecting the wet multi-plate clutch. 2. The first rotary body is coaxially connected to the outer peripheral side of the second rotary body so as to be relatively rotatable, and the wet multiple disc clutch is formed in a radial gap between the rotary bodies. The first rotating body, a clutch pressing member capable of pressing the wet multi-plate clutch from an end portion, and an operating shaft extending from the clutch pressing member to the cooling water passage through the axial center portion of the second rotating body. The operating shaft is provided with the temperature-sensitive member at the extending end thereof, and the operating shaft and the clutch pressing member are moved in the axial direction by deformation of the temperature-sensitive member in the cooling water passage, and 2. The water pump according to claim 1, wherein the wet multi-plate clutch is connected and disconnected. 3. The wet multi-plate clutch includes a first clutch plate engaged with the first rotating body, and a second clutch plate engaged with the second rotating body. 3. The water pump according to claim 1, wherein the thermal expansion coefficients of the second clutch plates are different from each other.