GB2333580A - Pump assembly - Google Patents

Abstract

A divide drive for use in a multiple pump assembly 2 comprises a driven input shaft 8, a drive shaft 14 coupled to the input shaft 8 for delivering torque to the individual pump sets of the multiple pump assembly 2 and at least one sacrificial coupling 18 mounted on the drive shaft 14, the or each such coupling 18 driving an individual pump set.

Description

TITLE Divide Drive in Multiple Pump Assembly DESCRIPTION Inventive Field: The invention relates to multiple pump assemblies and in particular to means of ensuring that at least one of the pump sets within the multiple pump assembly achieves priority over the other sets in the event of incipient failure.

Background Art: Multiple pump assemblies are extensively used in the automotive industry for supplying fluid to various devices. They generally comprise two or more individual pump sets, each having a driving gear rotatably mounted on a common shaft that extends substantially through the axial length of the assembly. The common shaft is itself driven either directly, or through some coupling device, by the engine.

Frequently, each of the individual pump sets is used for a different purpose. For example, one such pump set may supply lubrication fluid to the engine, another may be incorporated in the cooling system and yet another may provide actuation for the transmission.

An inherent problem associated with this type of system is that in the event of incipient failure, the common shaft of a multiple pump assembly continues to drive all of the individual pump set gearwheels until eventual failure.

When this happens none of the pumps can continue to operate.

Some of the tasks performed by the individual pump sets are more important than others. Therefore, for safety reasons or to avoid damage to key components, it would be beneficial for the multiple pump assembly to sacrifice the operation of an individual pump set that carries out a less important role to ensure that a higher priority pump set continues to function at the first signs of failure.

The Invention A divide drive for use in a multiple pump assembly comprising a driven input shaft, a drive shaft coupled to the input shaft for delivering torque to the individual pump sets of the multiple pump assembly and at least one sacrificial coupling mounted on the drive shaft, the or each such coupling driving an individual pump set.

The strength of the drive shaft is preferably greater than that of the or each sacrificial coupling.

It is preferable for each of the sacrificial couplings to drive an individual pump set and that the or each sacrificial coupling has a relative strength which is dependent upon the functional importance of the individual pump set which it is driving. Pumps having low priority roles are preferably driven by couplings having relatively low strength.

It is preferable that the highest priority pumps within the assembly are directly coupled to the drive shaft.

Drawings The sole Figure illustrates a sacrificial divide drive arrangement according to the invention.

The multiple pump assembly 2 comprises two individual pump sets 16 and 22. Each of these individual sets 16 and 22 is used for a different purpose and each has a different priority.

The multiple pump assembly 2 may be driven directly from the engine shaft or more commonly, as illustrated in this embodiment, the input shaft 8 of the multiple pump assembly 2 may be coupled by gearing or-some other means to the main engine shaft.

In this instance an input gear 10 drives the input shaft 8 of the multiple pump assembly 2. In turn the input shaft 8 is coupled by splines 12 to drive a quill shaft 14.

The quill shaft 14 firstly provides torque to the low priority pump set 16 through a splined intermediate sacrificial coupling 18 and secondly the quill shaft 14 is coupled directly via splines 12' to the drive shaft 20 of the high priority pump set 22.

The design is arranged such that the strength of the sacrificial coupling 18 is sufficiently less than that of the quill shaft 14. This ensures that in the event of a seizure, failure or lock up of the low priority pump 16, the coupling 18 will fail before the quill shaft 14 and hence the drive is consistently maintained to the high priority pump set 22.

It is apparent that this concept can be extended so that the quill shaft 14 may drive more than one pump set via sacrificial couplings 18. Additionally the strength of each such coupling 18 can be selectively chosen. This enables the manufacturer to rank all the individual pump sets within the multiple pump assembly 2 in order of priority.

It is also apparent that more than one pump set can be directly coupled to the quill shaft 14.

Claims (6)

1. CLAIMS 1. A divide drive for use in a multiple pump assembly comprising: a driven input shaft; a drive shaft coupled to the input shaft for delivering torque to the individual pump sets of the multiple pump assembly; and at least one sacrificial coupling mounted on the drive shaft, the or each such coupling driving an individual pump set.
2. 2. A divide drive according to claim 1, wherein the strength of the drive shaft is greater than the strength of the or each sacrificial coupling.
3. 3. A divide drive according to claim 1 or claim 2, wherein the or each sacrificial coupling has a relative strength that is dependent upon the functional importance of the individual pump set which it is driving.
4. 4. A divide drive according to any preceding claim, wherein the or each pump set having the highest priority in the event of incipient failure is directly coupled to the drive shaft.
5. 5. A divide drive according to any preceding claim, wherein the drive shaft is a quill shaft.
6. 6. A divide drive as hereinbefore described with reference to the drawing.