GB2334559A - A water pump seal arrangement - Google Patents

Abstract

A water pump seal arrangement comprising a seal plate (1) and a vent plate (2) secured together in a juxtaposed position with respective shaft orifices (3, 4) aligned. A vent channel (8) within the vent plate (2) being coupled to the vent orifice (8) in the seal plate (1) in order to provide an evaporation passage for the shaft bearing constituted by orifices (3, 4). The vent orifice (7) being coupled to atmosphere. The arrangement constituted by plates (1, 2) being relatively thin and so being less problematic with regard to drive train length for the water pump. The seal plate (1) and orifice (3) including an oil seal.

Description

A WATER PUMP SEAL ARRANGEMENT The present invention relates to a water pump seal arrangement and more particularly to a water pump seal arrangement for use in association with a motor vehicle in order to reduce the problems of space constraint within that vehicle's engine compartment.

There is a continuous pressure to develop high-performance motor vehicles and particularly improve performance within small motor vehicles.

Unfortunately, such smaller motor vehicles generally have a smaller engine compartment and so it is difficult to accommodate conveniently all the components. Furthermore, it is necessary to consider where certain hard components can be located within the motor vehicle to meet legislative requirements with regard to crumple zones upon impact, etc.

One particular concern is with regard to water pump location within a small but relatively high performance motor vehicle. Typically, the water pump in a relatively high performance vehicle will be driven from the super charger. This super charger will operate at something in the order of 2.3 times the engine speed whilst the water pump will operate at between 0.8 and 1.0 times the engine speed in order to avoid air locks, etc. Thus, it will be appreciated that some form of gear coupling must be included within the drive train between the super charger and the water pump to achieve the necessary drive reduction.

The provision of a gearing mechanism between the super charger and the water pump necessitates a supply of lubricating oil whilst the water pump should be protected from contamination with such oil. The oil and water should be kept separate. This separation is achieved traditionally through a casting coupling the gear drive chain between the super charger and the water pump. However, it will also be appreciated that the water pump must provide an evaporation pathway to accommodate the expansion of the water coolant pumped thereby. This requires that the casting is relatively complex and will normally include some drill machining to provide this pathway. A further problem with castings is that, in order to maintain the necessary strength and to accommodate the pathway etc, it is normal for the casting to have a relatively significant length. This can cause problems with regard to accommodation within small engine compartments and added weight.

It is an objective of the present invention to provide a water pump with a seal arrangement which substantially relieves the above-mentioned problems.

In accordance with the present invention there is provided a water pump seal arrangement comprising a seal plate and a vent plate, said seal plate including a first water pump impeller shaft orifice and a vent orifice, said vent plate including a second water pump impeller shaft orifice and a vent channel extending from said second water pump impeller shaft orifice, said seal plate and said vent plate being held in a sealed juxtaposed position with said respective first and said respective second water pump impeller shaft orifices aligned and said vent channel being coupled to said vent orifice, said vent channel providing a passageway for evaporation/lubrication of an impeller shaft bearing consisted by said respective first water pump impeller shaft orifice and said respective second water pump impeller shaft orifice.

The impeller shaft orifices in respective seal plate and vent plate may be turreted to extend perpendicularly from each respective plate.

The vent channel may be swaged during a pressing process into the vent plate.

The seal plate and the vent plate may be made from metal or a plastics material.

Said first water pump impeller shaft orifice in the seal plate may incorporate a bush-type seal in order to prevent ingress of oil to the said second water pump impeller shaft orifice in said vent plate.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawing.

The essential problem with regard to a water pump seal arrangement is providing adequate surity of separation of water and oil whilst allowing for an evaporation expansion pathway. Previously, this was achieved using a casting appropriately machined to provide the necessary pathways. Such castings are bulky and can present a weight penalty. Such problems can present significant obstruction to development within small engine compartment vehicles.

The present invention provides a water seal pump arrangement which will be generally 0.8 mm thick and may be made from relatively light metal, eg. aluminium or plastics material. Referring to the drawing, the water pump seal arrangement comprises a seal plate 1 and a vent plate 2. In the exploded view illustrated in the drawing, the plate 1 and the plate 2 are separated but it will be appreciated in use the plates 1, 2 are brought into juxtaposed alignment with a respective shaft orifice 3 in the seal plate 1 aligned with a second shaft orifice 4 in the vent plate 2. The respective plates 1, 2 will have a thickness in the order of 0.4 mm and so the arrangement comprising plates 1, 2 will have a combined thickness in the order of 0.8 mm.

Typically, the respective orifices 3, 4 will include respectively turreted skirt areas 5, 6 extending substantially perpendicular from each respective plate 1, 2. Thus, when assembled in the arrangement the respective orifices 3, 4 with skirts 5, 6 constitute an effective bearing for a shaft to be accommodated therein.

The seal plate 1 also incorporates a vent orifice 7 generally at its periphery.

The vent plate 2 incorporates a vent channel 8 which extends from the orifice 2/skirt 6. When assembled, this vent channel 8 is coupled to the vent orifice 7. Thus, a vent or evaporation passageway is provided from the orifice 2/skirt 6.

To secure the respective plates 1, 2 together, location bolt apertures 9 are located coincidentally in each respective plate 1, 2. Furthermore, the plates 1, 2 may be secured together by furnace brazing and/or using a sealing agent. Generally, the plates 1, 2 will be held together in a sealed juxtaposed relationship in order to prevent radial egress of fluids.

As indicated above, it is of importance to maintain a seal between the oil side and the water side of the water pump arrangement. Thus, the seal plate 1 will incorporate within the orifice 3/skirt 5 a bush-type seal. This may be of the carbon type or an O-ring arrangement could be utilised.

Thus, oil will generally be prevented from passing through the orifice 3, however, it may be beneficial to allow a drip leakage in order to lubricate the shaft bearing constituted by orifices 2, 3 and skirts 5, 6..

The vent plate 2 incorporating the vent channel 8 is arranged on the water side of the arrangement. Thus, the shaft passing through the bearing constituted by orifices 3, 4 and including an impeller will be located adjacent the vent plate 2. In order to avoid potential problems as a result of impeller cavitation in the water coolant and inherent evaporation of that coolant as it heats up, an evaporation pathway must be provided from the cavity including the pumped impeller. This pathway is provided through the slip passage between an impeller shaft passing through the orifice 4 /skirt 6 and the vent channel 8 coupled to the vent orifice 7. The vent orifice 7 will typically be coupled through appropriate means to atmosphere. Thus, piping 10 is provided.

The respective plates 1, 2 are formed typically by a pressing process.

However, if a plastics material is used to form these plates 1, 2 it will be appreciated that a moulding procedure may be applicable. The seal plate 1 generally comprises a flat pressing with an appropriate skirt 5 either produced during press fabrication or subsequently attached by a brazing technique. The orifices 3, 7 and apertures 9 can be drilled or press cut as required. Similarly, the vent plate 2 can be press formed with the skirt 6 either formed during such pressing or attached subsequently. The orifice 4 and aperture 9 may be drilled or press cut.

The vent channel 8 will normally be formed during a pressing process by swage deformation about a former. The vent passage 8 extends from the periphery of the second orifice 4 and upon assembly of the plates 1, 2 the passage 8 is coupled to the vent orifice 7. Thus, the association of plate 1 and the vent passage 8 creates a passageway which is open at the second orifice 4 and the vent orifice 7. This passageway allows egress of evaporation from a water coolant. As indicated previously, the orifice 7 will normally be coupled to atmosphere through appropriate conduit piping 10.

It will be appreciated by those skilled in the art that rather than constituting a simple straight channel, the vent passage could incorporate various features to provide for better control of evaporation. For example, the vent passage could incorporate an expanded cavity into which the evaporation and any condensate could be accommodated prior to venting to atmosphere. Thus, transient effects could be accommodated without the loss of water coolant. Furthermore, the passageway could be zig-zagged or indirect for similar reasons.

It will be appreciated that typically the arrangement comprising juxtaposed plates 1, 2 will be associated with other mountings within a motor vehicle engine. Thus, the vent hole 7 and so the passage 8 would normally be located in a flat extension of each respective plate 1 which is beyond the periphery of associated mountings either side of the arrangement of plates 1, 2 . This will allow easier access to the vent orifice 7 for coupling along conduits to atmosphere.

It will be appreciated that essentially the vent passage 8 must initiate from the orifice 4 in the vent plate 2 but by suitable swage deformation of the vent plate 2 and reciprocal deformation in the seal plate 1 a proportion of the vent passage could be located in the seal plate 1. Thus, an initial portion of the vent passage will be coupled to the orifice 4 whilst a bulge deformation in the seal plate 1 would overlap with this initial deformation in the vent plate 2 and extend to a vent orifice which is coupled to atmosphere. In such an embodiment it will be appreciated that a good seal must be provided to ensure that oil cannot penetrate the bulge deformation in the seal plate 1. However, it will be understood that such an arrangement could relieve the necessity of providing a flat section at the periphery of the plate 2 to accommodate the coupling between the vent passage 8 and the vent orifice 7.

Claims (8)

1. CLAIMS 1. A water pump seal arrangement comprising a seal plate and a vent plate, said seal plate including a first shaft orifice and a vent orifice, said vent plate including a second shaft orifice and a vent channel extending from said second shaft orifice, said seal plate and said vent plate being held in a juxtaposed position with said respective first and said respective second shaft orifices aligned and said vent channel being coupled to said vent orifice, said vent channel providing a passageway for evaporationllubrication of a shaft bearing constituted by said respective first shaft and said respective second shaft orifice.
2. 2. An arrangement as claimed in Claim 1, wherein the seal plate and the vent plate are held in a juxtaposed position with a seal therebetween.
3. 3. An arrangement as claimed in Claim 1 or Claim 2, wherein said respective first orifice and/or said second respective orifice are turreted with skirt portions extending substantially perpendicular from each respective plate.
4. 4. An arrangement as claimed in any preceding claim, wherein said first shaft orifice incorporates an oil seal to prevent egress of oil between said first shaft orifice and said second shaft orifice.
5. 5. An arrangement as claimed in any preceding claim, wherein said seal plate incorporates a bulge deformation which is coupled to said vent orifice and said vent passage in said vent plate.
6. 6. An arrangement as claimed in any preceding claim, wherein said vent channel is produced by swage deformation during press formation of said vent plate.
7. 7. An arrangement as claimed in any preceding claim, wherein said seal plate and/or said vent plate are formed from a metal or a plastics material.
8. 8. A water pump seal arrangement substantially as hereinbefore described with reference to the accompanying drawing.