US3689786A

US3689786A - Dynamo electric machines

Info

Publication number: US3689786A
Application number: US147075A
Authority: US
Inventors: Peter Hunt
Original assignee: Rotax Ltd
Current assignee: Lucas Support Services Ltd
Priority date: 1970-05-26
Filing date: 1971-05-26
Publication date: 1972-09-05
Anticipated expiration: 1989-09-05
Also published as: DE2125386A1; FR2093783A5; GB1358844A

Abstract

This invention relates to a dynamo electric machine having a rotatable shaft with at least one machine component mounted on the shaft for rotation therewith. The shaft has an axial bore for the passage of a cooling fluid and cooling fluid distributor means mounted on the shaft for discharging cooling fluid on to the component. The cooling fluid distributor means comprises an annular chamber which communicates with the axial bore and with flow control means, the latter ensuring an even or substantially even discharge of fluid therefrom by means of centrifugal force when, in use, the shaft, the component, and the cooling fluid distributor means are rotated.

Description

United States Patent Hunt [ Sept. 5, 1972 [54] DYNAMO ELECTRIC MACHINES [72] inventor: Peter Hunt, Shipley, England [73] Assignee: Rotax Limited, Birmingham,

' England 22 Filed: May 26, 1971 [21] Appl. No.: 147,075

30 Foreign Application Priority Data May 26, 1970 Great Britain ..25,308/70- [52] US. Cl ..310/58 [51] Int. Cl. ..H02k 9/00 [58] Field of Search ..310/52, 54, 53, 58, 59, 61, 310/64, 59

[56] References Cited 2 I UNITED STATES PATENTS 3,480,810 11/1969 Potter ..310/61 3,145,314 8/1964 Becker ..310/64 3,318,253 5/1967 Campolong. ..310/64 Kudlacik ..310/61 Hauenstein 10/61 Primary Examiner- J. D. Miller Assistant Examiner-R. Skudy Att0rneyHolman & Stern 57 ABSTRACT This inventionrelates to a dynamo electric machine having a rotatable shaft with at least one machine component mounted on the shaft for rotation therewith. The shaft has an axial bore for the passage of a cooling fluidand cooling fluid distributor means mounted on the shaft for discharging cooling fluid on to the component. The cooling fluid distributor means comprises an annular chamber which communicates with the axial bore and with flow control means, the

latter ensuring an even or substantially even discharge of fluid therefrom by means of centrifugal force when, in use, the shaft, the component, and the cooling fluid distributor means are rotated.

'6 Claims, 3 Drawing Figures PATENTEDSEP 5 m2 3,689 786 SHEET 1 [IF 2 FIG];

INVENTOQ M ATTORNEYS PATENTED 1 2 3,689,786

SHEET 2 0F 2 INVENTOR /Z/@/Z ATTORNEYS is mounted on the shaft of the machine.

DYNAMO ELECTRIC MACHINES This invention relates to dynamo electric machines and more particularly to machines in which rotating components are cooled with cooling fluid. The object of the present invention is to provide a dynamo electric machine having improved means for discharging cooling fluid onto said rotating components of such a machine.

In accordance with the present invention there is provided a dynamo electric machine having a rotatable shaft with at least one machine component mounted on the shaft for rotation therewith, the shaft having an axial bore for the passage of a cooling fluid and cooling fluid distributor means mounted on said shaft for discharging cooling fluid onto said component, said cooling fluid distributor means comprising an annular chamber which communicates with saidaxial bore and with flowcontrol means, the latter ensuring an even or substantially even discharge of fluid therefrom by means of centrifugal force when, in use, the shaft, said component, and said cooling fluid distributor means are rotated.

Conveniently, said component may be a rotor winding or a rectifier.

Preferably, said flow control means comprises an annular weirarranged sothat the free edge of the weir is disposed radially inwardly of a plurality of apertures formed in a wall of said annular chamber and through which apertures cooling fluid can in use pass between said annular chamber and said annular weir, the arrangement being such that in use an annular reservoir of cooling fluid will be formed behind the weir when the shaft is rotated, said reservoir being in fact filled by means of cooling fluid which flows through said aperdischarging from the flow control means passes between the end turns to effect more efficient cooling thereof.

The invention will now be more particularly described with reference to the accompanying drawings wherein:

FIG. 1 is a partially sectioned view of one embodiment of a dynamo electric machine according to the present invention,

FIG. 2 shows the end turns of a rotor winding which dynamo electric FIG. 3 is 'a fragmentary sectional view illustrating part of the dynamo electric machine shown in FIG. 1 on an enlarged scale.

Referring now to FIG. 1 of the drawings, there is shown an altemator, by way of example, which includes a stator having stator windings 11. Preferably, the stator is mounted inside a cylinder 12 which lies in contact with the inner surface of a casing 13 of the alternator. A scroll 14, formed on the inside 2 of the casing 13, is covered by said cylinder to provide a path for oil or other cooling fluid, which on passing through said scroll effects cooling of the stator.

A shaft 15 is joumalled for rotation inbearings provided at each end of the shaft and the right hand end of the shaft 15 (as viewed in FIG. 1) is adapted to receive a driving device (not shown) for the alternator.

A machine component in the form of a rotor assembly 16 is mounted on the shaft 15 for rotation therewith and windings (only the end turns 17 of which are shown) are mounted on a rotor core 18 so as to provide a number of poles. The shaft 15 is formed with an axial bore 19 to provide a passage for the cooling fluid which is pumped (by means not shown) through a duct 20 formed in the easing, into the scroll 14 and thence through a further duct 21 and into the bore l9.v

Cooling fluid distributor means indicated generally by the reference numeral 22 arealso mounted on the shaft 15 for rotation therewith, said cooling fluid distributor means being disposed radially inwardly of the end turns 17 of the rotor windings. The cooling fluid distributor means 22 comprise a first annular chamber 23 and a second annular chamber 24 which have an annular partition 25 disposed therebetween. The first annular chamber 23 is connected to the bore 19 for communication therewith by one relatively large aperture 26 and is connected to the second annular chamber 24 for communication therewith by a plurality of smaller axially extending apertures 27 provided near the radially outward edge of the partition 25. The second chamber 24 is formed in its outer peripheral wall 28 with a plurality of openings preferably in the form of axially extending circumferentially spaced slots 29 through which cooling fluid, in use, is discharged. This second chamber is further provided with flow control means 30 for ensuring an even or substantially even discharge of fluid from the slots 24 in' the outer peripheral wall 28 of the second chamber 24 by means of centrifugal force when, in use, the shaft 15, the rotor assembly 16 and the cooling fluid distributor means 22 are rotated. The aforesaid flow control means 30 comprises a cylindrical tube 31 the outer periphery of which engages at its end remote from the rotor assembly 16 the interior of the outer peripheral wall of the first chamber 23 and which has a radially inwardly extending annular abutment 32 secured to or formed integrally with the other end thereof, the abutment 32 in effect, forming an annular weir. The latter is so arranged that its free edge is disposed radially inwardly of the apertures 27 formed in the partition 25 so that in effect an annular reservoir of cooling fluid will be formed behind the weir when the shaft 15 is rotated, said reservoir being filled by means of cooling fluid which is flung out through the aperture 26 and into the first chamber 23 by centrifugalforce, said cooling fluid thence flowing through the partition apertures 27 and is then held in position behind the weir by centrifugal force. When the reservoir is, in use, full, the cooling fluid will flow I past the weir and will thence be discharged through the slots 29 in the outer peripheral wall of the second I chamber by centrifugal force. The provision of the weir ensures an even or substantially even discharge of fluid from the aforesaid slots which, by nature of their size, will not become clogged and this thus reduces the occurrence of possible hot spots (due to uneven cooling) on the rotor windings to a minimum. Cooling fluid used in cooling the rotor windings falls into a sump (not shown) and may then be pumped away to a heat exchanger.

Conveniently, where said component is in the form of a rotor winding as is the case in the above described embodiment of the invention, then the end tums' 17 of the rotor winding may be axially spaced from each other (as is more clearly shown in FIG. 2) such that cooling fluid discharging from the slots 29 will pass between the end turns thus effecting more efficient cooling thereof.

In hitherto known arrangements for effecting cooling of components mounted on the shaft of a dynamo electric machine either small apertures have been formed in the wall of the shaft or spraying nipples have been mounted directly on the shaft or on a sleeve connected to the shaft. However, due to the smaller diameter of apertures through which the fluid has previously been discharged, these apertures have been subject to clogging, thus resulting in hot spots occurring on components which are to be cooled.

Although the invention has been described in relation to an alternator and the cooling of a rotor thereof, it could of course be applied to any other type of dynamo electric machine in which any component, such as a winding or a rectifying element, is to be cooled by cooling fluid.

Moreover, it is to be understood that the scroll 14 is not essential and it may thus be dispensed with if desired. In this case the ducts 20 and 21 may also be dispensed with, cooling fluid entering the axial bore 19 through an axially extending passage formed in one end of the alternator casing.

In addition, it is also to be understood that if desired the second annular chamber 24 may also be dispensed with.

I claim:

l A dynamo electric machine having a rotatable shaft, at least one machine component mounted on the shaft for rotation therewith, an axial borewithin the shaft for the passage of a cooling fluid and cooling fluid distributor means mounted on said shaft for discharging cooling fluid onto said component, said cooling fluid distributor means comprising an annular chamber which communicates with said axial bore and flow con-. trol means with which said annular chamber also communicates, said flow control means comprising an annular weir arranged so that the free edge of the weir is disposed radially inwardly of a plurality of apertures formed in a wall of said annular chamber and through which apertures cooling fluid can in use pass between said annular chamber and said annular weir, the arrangement being such that in use an annular reservoir of cooling fluid will be formed behind the weir when the shaft is rotated, said reservoir being filled by means of cooling fluid which flows through said apertures and which is then held in position behind the weir from which it is subsequently evenly discharged by means of centrifugal force.

2. A dynamo electric machine as claimed in claim 1 wherein said component is a rotor winding.

3. A dynamo electric machine as claimed in claim 1 wherein said annular weir is disposed within a further annular chamber which is formed in its outer wall with a plurality of openings through which cooling fluid will, in use be discharged, said apertured wall forming a partition between the two annular chambers.

5. A dynamo electric machine as claimed in claim 4 wherein said openings formed in the peripheral wall of said further chamber are in the form of axially extending circumferentially spaced slots.

6. A dynamo electric machine as claimed in claim 2 wherein the end turns of said winding are axially spaced from each other,-the arrangement being such that fluid discharging from the flow control means passes between the end turns to effect more efficient cooling thereof.

Claims

1. A dynamo electric machine having a rotatable shaft, at least one machine component mounted on the shaft for rotation therewith, an axial bore within the shaft for the passage of a cooling fluid and cooling fluid distributor means mounted on said shaft for discharging cooling fluid onto said component, said cooling fluid distributor means comprising an annular chamber which communicates with said axial bore and flow control means with which said annular chamber also communicates, said flow control means comprising an annular weir arranged so that the free edge of the weir is disposed radially inwardly of a plurality of apertures formed in a wall of said annular chamber and through which apertures cooling fluid can in use pass between said annular chamber and said annular weir, the arrangement being such that in use an annular reservoir of cooling fluid will be formed behind the weir when the shaft is rotated, said reservoir being filled by means of cooling fluid which flows through said apertures and which is then held in position behind the weir from which it is subsequently evenly discharged by means of centrifugal force.

3. A dynamo electric machine as claimed in claim 1 wherein said component is a rectifier.

4. A dynamo electric machine as claimed in claim 1 wherein said annular weir is disposed within a further annular chamber which is formed in its outer wall with a plurality of openings through which cooling fluid will, in use be discharged, said apertured wall forming a partition between the two annular chambers.

6. A dynamo electric machine as claimed in claim 2 wherein the end turns of said winding are axially spaced from each other, the arrangement being such that fluid discharging from the flow control means passes between the end turns to effect more efficient cooling thereof.