GB2138889A - Impeller pump - Google Patents

Abstract

A rotary pump having a flexible pump wheel (impeller) inside the main body 2 of a pump housing, comprises a component 4 projecting from one end of the main body. A pump shaft 13 supports the impeller and is provided with a driven member 14 for connection to a driving member. The component 4 forms a bearing housing supporting at least one radial bearing 16 with an outer race 18 attached to the bearing housing, and an inner race 17 attached to the pump shaft. <IMAGE>

Description

SPECIFICATION Impeller pump The present invention relates to an impeller pump, that is to say a rotary pump having a flexible pump wheel, known as the impeller, inside a pump housing. More specifically, the invention relates to an impeller pump having a pump housing with a main body from one end of which projects a component which constitutes an integral part of the pump hous ing or which is permanently attached to the pump housing and a pump shaft which sup ports the impeller and extends through and past the projecting component of the pump housing and which at the projecting end which extends past the projecting component of the pump housing is provided with a driven member for connection to a driving member.

Impeller pumps of the kind described above have been familiar for some time. The older designs include, for example, the pump which was sold during the 1 960s by Volvo Penta AB under the model designation PENTA 465. A similar pump is also described in British Patent Specification 1 583 643. These previously disclosed pumps, which are designed to operate at very high rotational speeds, are equipped with a ball bearing between the projecting end of the pump housing and the driven member. More specifically, the roller bearing is passed over the projecting end so that the inner race of the bearing is secured to the driven member or to an adaptor which in turn is secured to the driven member. The inner race thus remains stationary together with the pump housing, whereas the outer race rotates at the same rotational speed as the pump wheel.However, this design also suffers from considerable disadvantages, which become particularly noticeable when the pump is to be used at very high rotational speeds. This has to do with the fact that the diameter of the bearing must be comparatively large and with the fact that the outer race rotates. Both these factors increase considerably the rotating mass and produce an unfavourable loading on the bearing, as well as increasing the problem of causing the lubricant to remain inside the bearing. The external dimensions of the pump also increase, which leaves less space available for the attachment of the driven member to, for example, a crankshaft belt pulley or some other driving member. Another disadvantage is the fact that cooling water is able easily to penetrate the bearing if the shaft seal is not tight.

The object of the invention is to eliminate the aforementioned disadvantages of the existing designs which are based on the pump operating principle described by way of introduction. More specifically, the object of the invention is to offer a pump suitable for high rotational speeds but with a lower rotating mass than previously disclosed pumps yet offering equivalent performance. One particu lar object of the invention is to offer a pump with a more favourable bearing loading than previously disclosed pumps.

A further object is to offer a pump with a bearing housing which may have smaller external dimensions than previously disclosed high-speed pumps which, amongst other thins, offers the advantage of providing more space for the attachment of the driven member to a driving member.

According to the present invention we provide a rotary pump having a flexible pump impeller inside the main body of a pump housing, comprising a bearing housing projecting from one end of the main body which either forms an integral part of the pump housing or is permanently attached to the pump housing, and a pump shaft which supports the impeller and extends through and past said projecting component of the pump housing to an end which is provided with a driven member for connection to a driving member, wherein the internal diameter of said bearing housing is considerably greater than the diameter of the pump shaft and wherein inside the bearing housing there is arranged firstly at least one radial bearing with an outer race which is attached to and is thus stationary with respect to the bearing housing, and secondly an inner race which is attached to the pump shaft for rotation therewith.

The bearing housing may consist of a tubular component which, for example by means of reinforcing fins or in some other way, is secured to the main body of the pump housing, in such a way that the main body and the bearing housing together form an integrated cast unit. Also conceivable is the alternative of causing the main body and the bearing housing to be manufactured in two parts which, by means of bolts or in some other way, are joined together to form a single unit.

The pump chamber is sealed in the area of the projecting pump shaft by means of a sealing arrangement between the pump shaft and the main body of the pump housing at an axial distance from the bearing housing. A radial seal may suitably be used in said area.

By the use of this arrangement it is possible in the case of the pump in accordance with the present invention to prevent the pump from growing in an axial sense by comparison with previously disclosed pumps of the kind described by way of introduction.

Other characteristics and advantages of the present invention will become clear from the Patent Claims and from the following description of a preferred embodiment.

In the following description of a preferred embodiment reference will be made to the attached drawings, of which: Figure 1 shows an end view of the pump in accordance with the preferred embodiment, and Figure 2 shows a section on line Il-Il of Fig. 1.

In Fig. 2 the number 1 is used to designate a pump housing cast in a single piece. The pump housing 1 consists of a main body 2 with a pump chamber 3 and a bearing housing 4 which forms a component projecting from the main body 2. The bearing housing 4 is joined to the main body 2 by means of four reinforcing fins. The pump chamber 3 is closed in a previously disclosed manner by means of a covering plate 6 at one end. The input and output pipes for the pump chamber 3 have been designated 7 and 8 respectively.

In the roof of the pump chamber 3 is secured by means of a screw 9 a cam 10 intended in a previously disclosed manner to cause the vanes of an impeller 11 to bend as it rotates, thereby giving the impeller the desired pumping effect. A projection 1 2 on the pump housing 1 forms the attachment point for an anti-torque stay.

A pump shaft 1 3 is joined in a previously disclosed manner to the impeller, that is to say to the flexible pump wheel 11, and extends in an axial direction out from the main body 2 of the pump housing, through the bearing housing 4, and is attached at its outer end to a driven member 14. The driven member 14 is in turn attached to a suitable driving member, for example a driving pulley, or directly to a crankshaft fan drive pulley.

The manner in which the impeller 11 and the driven member 14 are attached to the pump shaft may be by means of splined couplings or some other previously disclosed coupling device permitting the concentric connection of a shaft and a rotating member. Inside the bearing housing are arranged a pair of ball bearings 16. The inner races 1 7 of the ball bearings are attached to the pump shaft 1 3 and are thus so arranged as to rotate together with the pump shaft 1 3. The outer races 1 8 of the ball bearings are, on the other hand, attached to the inside of the bearing housing 4 and are thus stationary when the pump shaft 13 rotates.

For the purpose of sealing the pump chamber 3 a radial seal 1 9 is arranged inside the end wall 20 of the main body 2 of the pump housing, that is to say at an axial distance from the bearing housing 4. The radial seal 1 9 is held in position axially by. means of a supporting washer 21.

Claims (5)

1. A rotary pump having a flexible pump impeller inside the main body of a pump housing, comprising a bearing housing projecting from one end of the main body which either forms an integral part of the pump housing or is permanently attached to the pump housing, and a pump shaft which supports the impeller and extends through and past said projecting component of the pump housing to an end which is provided with a driven member for connection to a driving member, wherein the internal diameter of said bearing housing is considerably greater than the diameter of the pump shaft and wherein inside the bearing housing there is arranged firstly at least one radial bearing with an outer race which is attached to and is thus stationary with respect to the bearing housing, and secondly an inner race which is attached to the pump shaft for rotation therewith.

2. A pump according to claim 1, including a radial seal between the pump shaft and the main body of the pump housing in an end wall of the main body axially spaced from the bearing housing.

3. A pump according to claim 1 or 2, wherein the bearing housing consists of a tubular component which is connected by means of reinforcing fins to the main body of the pump housing in such a way that the main body and the bearing housing together form an integrated cast unit.

4. A pump according to any one of claims 1 to 3, wherein the outer end of the pump shaft is connected concentrically with the driven member.

5. A rotary pump constructed substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.