GB2499980A

GB2499980A - Water pump and clutch assembly for cooling an internal combustion engine

Info

Publication number: GB2499980A
Application number: GB201202088A
Authority: GB
Inventors: Carmine Pezzella; Luca Borgia
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2012-03-07
Filing date: 2012-03-07
Publication date: 2013-09-11
Anticipated expiration: 2032-03-07
Also published as: GB201202088D0; GB2499980B

Abstract

A water pump assembly for cooling an internal combustion engine (21, fig.3) comprises a water pump housing 4, an electromagnetic clutch including an electromagnetic coil 2 housed in a body 3 that is assembled on the water pump housing, and a pulley 5 assembled on the water pump by means of a bearing 6. The electromagnetic clutch, the pulley and the pulley bearing are assembled on the water pump by removable threaded fasteners 7, 8, such as screws or bolts. The pulley and the pulley bearing are assembled on the water pump shaft 15 and the electromagnetic clutch is assembled on the water pump housing. Preferably, the water pump has a body that includes at least one radially extending flange 10 having holes 11 for the passage of the threaded fasteners 7, where the body housing the electromagnetic coil has internal threads 20 for receiving the fasteners. The internal threads may be provided in extensions of the clutch body. In use, the assembly is designed to enable the clutch and the water pump to be serviced or replaced independently with the further possibility of removing the clutch and the pulley without removing the water pump from the engine.

Description

1

5 WATER PUMP SWITCHABLE BY A CLUTCH.

Technical Field

The present invention refers to a water pump switchable by a clutch and, more particularly, to a water pump of the type provided with an electromagnetic clutch, for 10 selectively switch on and off the pump operation according to the engine temperature to enhance engine performances and energy savings.

Background

In a fluid-cooled engine assembly, coolant recirculation is performed by a water pump 15 having a shaft and an impeller to pump cooling liquid in the engine cooling jacket provided to cool the engine in a vehicle. The shaft is connected to a pulley that is operated by a drive belt, and the impeller is operated by the shaft being rotated by the belt and the pulley.

To reduce C02 emission and improve engine performance, switchable water pumps 20 have been introduced. A switchable water pump in a combustion engine is a water pump equipped with a switching system (a so called clutch) in the drive pulley. By switching off the water pump during the warm up, it is possible to reduce the power absorption and warm up time.

Generally, such a switchable water pump is provided with an electromagnetic clutch 25 type that is operated according to the temperature of the engine. An electromagnetic clutch for water pumps generally has a coil mounted static on the pump and a rotor that is connected to the pump shaft; the pulley is mounted on the pump through a bearing and has an armature that is normally spaced from the rotor.

The electromagnetic clutch operates via an electric actuation and transmits torque 30 mechanically. Voltage/current is applied to the coil when the clutch has to be actuated. The coil becomes an electromagnet and magnetizes the rotor of the clutch. The magnetized rotor portion of the clutch attracts the armature, that is pulled against the rotor and a frictional force is applied at contact area: the rotor is put into rotation and the pump shaft is therefore rotated, too.

2

Alternative embodiments are known where the rotor of the clutch in normally biased against the armature, in frictional engagement with it; in these cases the actuation of the electromagnet disconnects the rotor from the armature.

By the switchable clutch, recirculation of the cooling fluid is possible only when 5 necessary for cooling: as an example, no recirculation is carried out when the engine is warming up after having been started.

Known clutch-water pump assemblies are costly and difficult to maintain. It is therefore an aim of the present invention to provide a novel switching water pump, including an electromagnetic clutch, that is easy to assemble and to maintain.

10 This aim is reached by the present invention that provides a water pump assembly for cooling an internal combustion engine, that includes electromagnetic clutch comprising an electromagnetic coil housed in a body that is assembled on the water pump housing and a pulley assembled on said water pump by means of a bearing, wherein said electromagnetic clutch, said pulley and said pulley bearing are assembled on the water 15 pump by removable threaded fasteners.

With the wording "threaded fasteners" it is defined any fastener that is provided with a thread and, more generally, any fastener that can be easily secured to and removed from a body in a non-destructive way. Exemplary embodiments are screws and bolts. Preferred embodiments are disclosed in the dependent claims.

20 According to an exemplary embodiment of the present invention, the electromagnetic coil is assembled on the water pump housing by screws and the pulley and the bearing pulley are assembled on the water pump by screw. Preferably, the pulley and the bearing pulley are assembled on the water pump hub, by a screw.

According to a further exemplary embodiment the water pump has a body that includes 25 at least one flange having holes for the passage of said threaded fasteners and in that said electromagnetic coil is housed in a body that has internal threads for receiving said fasteners.

A further object of the invention is a water pump assembly as above discussed, as a component of an internal combustion engine.

30 The invention provides several advantages over the prior art; initially, there is a cost saving in service operation because it is possible to service or to replace independently the clutch and water pump.

Secondly, the invention results in the possibility to remove the clutch and the pulley without removing the pump from the engine.

3

Further advantage are that the clutch is easier to be adapted to different kind of pump and a greater freedom in the sourcing of the clutch to external providers.

Brief Description of the Drawings 5 Further advantages and features of an embodiment of the present invention will be more apparent from the description below, provided with reference to the accompanying drawings, purely by way of a non-limiting example, wherein:

- fig. 1 is a sectional side view of a water pump assembly according to an embodiment of the present invention;

10 - fig. 2 is a side view of the water pump assembly of fig. 1;

- fig.3 is a front view of the water pump assembly of fig. 1 mounted on the engine; and

- fig.4 is an exploded view of the water pump assembly of fig. 1.

15 Detailed Description

According to an exemplary embodiment of the present invention a water pump assembly for cooling an internal combustion engine 21, (shown in fig. 3), includes an electromagnetic clutch 2A comprising an electromagnetic coil 2 housed in a body 3 that is assembled on the water pump housing 4 and a pulley 5 assembled on the water 20 pump 1 by means of a bearing 6. Said electromagnetic clutch body 3, said pulley 5 and said pulley bearing 6 are assembled on the water pump by removable threaded fasteners 7, 8.

The pulley 5 is rotated under the action of a drive belt (not shown) connected in a known way to a main shaft (not shown) and, according to the switching of the 25 electromagnetic coil 2, the rotation of the water pump shaft 15 is either made integral to or independent from the rotation of the pulley 5, as disclosed hereinafter. The way the clutch is operated and its connection to the pulley 5 is known in the art and it is not an object of the present invention.

In a first embodiment, when the electromagnetic coil 2 is not powered, the rotation of 30 the water pump shaft 15 is made integral in known manners to the rotation of the pulley 5. Thus the pulley drives the water pump shaft 15, which in turn drives an impeller 13 adapted to pump a coolant in a coolant circuit (not shown) in order to control the operative temperature of the engine 21. When the coolant action of the coolant is not needed, e.g. at the start-up of the engine 21, the electromagnetic coil 2 is powered and 35 operates on the clutch member 12. Thus the water pump shaft 15 and, consequently,

4

the impeller 13 are disengaged in a known manner from the rotation of the pulley 5 and so the coolant is not pumped in the coolant circuit.

In a further embodiment the clutch 2A can be arranged so that its operation is inverted, that is when the electromagnetic coil 2 is powered, the rotation of the water pump shaft 5 15 is made integral to the rotation of the pulley 5 and vice versa.

As above mentioned, clutch body 3 is secured to the pump body 4 by threaded fasteners 7. In greater detail, the exemplary embodiment shown in the figures includes a water pump housing 4 that is provided with a radially protruding flange 10. Flange 10 has holes 11 for the passage of the threaded fasteners 7 and the body 3 of the 10 electromagnetic coil 2 has internal threads 20 for receiving the threaded fasteners 7. In the shown embodiment, threads 20 are provided in extensions 22 of clutch body 3; preferably, the flange extends radially to the axis of the water pump housing 4 so as to provide a continuous arched surface projecting from the housing 4, the extensions 22 of the clutch housing 3 are secured by the fasteners on the flange 10. 15 The combination of extensions 22 and flange 10 provides an easy access to the fasteners and therefore easy maintenance of the pump.

Threaded fasteners 7 can be screws, bolts or any threaded connection apt to cooperate with the internal threads of the body 3 in order to couple the water pump housing 4 with the flanges 10 of the clutch body 3. Washers 9 can be placed between 20 the head of the fasteners 7 and the flanges 10 in order to prevent damages on said flanges 10 and distribute the load of said fasteners 7.

Alternatively both the clutch body 3 and the water pump housing 4 can be provided with flanges, apt to be coupled one to the other by suitable threaded fasteners, e.g. a coupling bolt - nut. Alternatively only the clutch body 3 can be provided with flanges 25 apt to be coupled by means of suitable threaded fasteners with the water pumps. Moreover different couplings of the water pump housing 4 and the clutch body 3 by means of threaded fasteners are contemplated and fall within the object of the present invention.

The pulley 5 is assembled onto the pulley bearing 6 and the pulley bearing 6 is 30 assembled onto the water pump 1.

In the embodiment shown in the figures the external portion 17 of the pulley bearing 6 is integral to the pulley 5 and the internal portion 18 of the pulley bearing 6 is secured to a pulley bearing support 16, that is secured to the water pump shaft 15.

As shown in fig. 1, a threaded fastener 8 is inserted into a threaded hole 14 in the 35 water pump shaft 15. A portion of the head of threaded fastener 8 engages with a

5

portion of pulley bearing support 16, that is in turn secured to the internal portion 18 of pulley bearing 6, thus securing pulley bearing 6 and pulley 5 in their operational position. A removable cover 19 covers and protects the head of the threaded fastener 8.

5 Threaded fasteners 8 can be screws, bolts or any threaded connection suitable to cooperate with internal threads of the water pump housing 4 in order to couple the assembling composed by the pulley 5 and the pulley bearing 6 to the water pump housing 4.

Figure 3 shows the water pump assembly according to the present invention mounted 10 on an internal combustion engine 21.

Several advantages are provided by the removable connections provided by the treaded fasteners 7, 8. First of all it is possible to replace independently the components 2, 3, 12 composing the clutch and the water pump 1. It is also possible to replace the pulley 5, the pulley bearing 6 independently from the components 2, 3, 12 15 composing the clutch 2A, thanks to the fact that the pulley is assembled on the pump shaft 15 i.e. separately from the clutch body 3.

Additionally, all the above components can be replaced without removing the water pump 1 from the engine 21.

Moreover it is possible to assemble a model of clutch on different models of water 20 pumps and vice versa.

While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, 25 applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended 30 claims and their legal equivalents.

6

REFERENCES INTO DRAWINGS

5

1.

water pump

2.

electromagnetic coil

2A.

clutch

3.

clutch body

4.

water pump housing

10

5.

pulley

6.

pulley bearing

7.

threaded fastener

8.

threaded fastener

9.

washers

15

10.

flanges

11.

holes

12.

clutch member

13.

impeller

14.

threaded hole

20

15.

pump shaft

16.

pulley bearing support

17.

external portion of the pulley bearing

18.

internal portion of the pulley bearing

19.

removable cover

25

20.

internal threads

21.

internal combustion engine

22.

extensions of the clutch body

Claims

1. A water pump assembly for cooling an internal combustion engine (21), that includes a water pump housing (4), an electromagnetic clutch (2A) comprising an electromagnetic coil (2) housed in a body (3) that is assembled on the water pump housing (4) and a pulley (5) assembled on said water pump (1) by means of a bearing (6), characterized in that said electromagnetic clutch, said pulley (5) and said pulley bearing (6) are assembled on the water pump by removable threaded fasteners (7, 8), and in that said pulley (5) and said pulley bearing (6) are assembled on the water pump shaft (15) and said electromagnetic clutch (2A) is assembled on said water pump housing (4).

A water pump assembly according to claim 1, wherein the water pump (1) has a body (4) that includes at least one flange (10) having holes (11) for the passage of said threaded fasteners (7) and in that said electromagnetic coil (2) is housed in a body (3) that has internal threads (20) for receiving said fasteners (7).

A water pump assembly according to claim 1, wherein said flange is extending radially to said water pump body (4) and said internal threads (20) are provided in extensions (22) of said clutch body (3).

A water pump assembly according to any previous claim, wherein removable threaded fasteners (7, 8) are selected from screws and bolts..

A water pump assembly according to any previous claim as a component of an internal combustion engine (21).