GB1594560A

GB1594560A - Electric motor with open-end spinning rotor for spinning machine

Info

Publication number: GB1594560A
Application number: GB1463978A
Authority: GB
Original assignee: BBC Brown Boveri AG Switzerland; BBC Brown Boveri France SA
Current assignee: BBC Brown Boveri AG Switzerland; BBC Brown Boveri France SA
Priority date: 1977-09-15
Filing date: 1978-04-13
Publication date: 1981-07-30
Also published as: FR2403404A1; CH622293A5; DE2746464A1; DE7731930U1; CS209543B2

Abstract

Electric motors as individual drives for open-end spinning machines require considerable power for cooling. This power can be saved by means of an arrangement which generates a sufficient air stream without a fan. For this purpose, the stator (2) of the motor (1) is provided with air-passage orifices (8) extending parallel to the longitudinal axis, and a housing (26), extending from the motor (1) to the rear side of the spinning rotor (13) and located at a short distance from the spinning rotor (13), is arranged. The high-speed spinning rotor (13) and the housing (26) arranged at a short distance from it work on the principle of the friction pump, an air stream being generated through the air-passage orifices (8). <IMAGE>

Description

(54) ELECTRIC MOTOR WITH OPEN-END SPINNING ROTOR FOR SPINNING MACHINE (71) WE, BBC BROWN, BOVERI & COMPANY LIMITED, a Swiss Company of CH-5401, Baden, Switzerland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- This invention relates to an electric motor having an open-end spinning rotor secured to a rotor shaft at the motor for use in an open-end spinning machine.

Low-power electric motors are cooled with air, a fan, which is generally disposed inside the housing and secured to the rotor shaft, serving to produce a stream of cooling air. The loss of power which such a fan causes is considerable and may amount to up to 20% of the total power input in highspeed electric motors such as are used, for example, as individual drives of open-end spinning rotors. The conventional motor cooling by means of the impeller blades of a fan is therefore uneconomical in open-end spinning machines.

In accordance with the invention, there is provided an electric motor having an openend spinning rotor secured to an end of a rotor shaft of the motor, the motor having a stator provided with air ducts which extend over the whole length of the stator and the motor also comprising a housing having an extension at its end adjacent the spinning rotor, a cavity being present inside the housing extension and a gap remaining between the spinning rotor and the housing, the arrangement being such that, when the motor is running, a flow of air is promoted through the ducts and into said cavity and thence through said gap.

The invention is based on the principle of the friction pump known from the DT-AS 2,056,898.

The essential advantage of the invention is to be seen in that instead of the air turbulence caused by the spinning rotor running at high speed, a stream of air traversing the motor is produced by the construction according to the invention.

The gap width between the spinning rotor and the housing preferably amounts to 1 2mm This spacing ensures, an adequate suction effect and accordingly a satisfactory stream of air, but at the same time the spacing is large enough to eliminate contact between the housing and the spinning rotor.

It is an advantage to make the extension at said end of the housing conical.

In addition, it is an advantage that a gap extending radially remains between said housing end and the back of the spinning rotor. An arrangement wherein the inner face of the conical end is directed towards an inner radius of the back of the spinning rotor is advantageous. Thus the stream of air is guided to the inner radius of the back of'the spinning rotor and the whole area of the back is effective. The air ducts of the motor may appropriately be disposed between a stator body and a stack of stator laminations and be uniformly distributed over the whole periphery. As a result, there is a satisfactory and uniform cooling. In order to reduce the air resistance, it is an advantage to provide, in end bearing plates of the motor, air apertures in the same number and arrangement as in the stator ducts, and to align the air ducts and apertures of motor and bearing plates with one another.In order to cool the ends of the stator winding, it is an advantage for additional air apertures, directed towards the ends of the winding, to be provided in the bearing plates. An air filter, which prevents the penetration of dust and dirt into the motor, may appropriately be disposed at the air inlet side of the motor.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section through an electric motor with an open-end spinning rotor; and Figure 2 is a cross-section through the stator of the motor illustrated in Figure 1.

Figure 1 an electric motor with a stator 2 and a rotor 3 is designated by 1. The stator 2 comprises a stator body 4, a stack of stator laminations 5 with a stator winding 6 and a bearing plate 7, 7* at each end. Cooling ducts 8 extending in the longitudinal direction are provided over the whole length of the stator body 4. The rotor 3 consist of a shaft 9 with a stack of rotor laminations 10 secured to this. The shaft 9 comprises two journals 11, 11 * and a shaft journal 12. The shaft journal 12 serves to receive an open-end spinning rotor 13. The journals 11, 11* form the rotating parts of two radial bearings 14, 14* which are lubricated by gas dynamics and the bearing bushes 15, 15* of which are inserted in the bearing plates 7, 7*. A bearing cover 16 which closes the radial bearing 14 is mounted at the outside of the bearing plate 7.Secured to the side of the bearing plate 7* adjacent to the spinning rotor 13 is a bearing cover 17 which closes the radial bearing 14* and which is provided with a central bore for the passage of the shaft 9. The bearing plates 7, 7* are provided with bores 18, 18*; 19, 19* and the number of bores 18, 18* corresponds to the number of cooling-air ducts 8. In order to achieve as low an air resistance as possible, the cooling-air ducts 8 and the bores 18, 18* are aligned with one another. Disposed at each end of the rotor 3 is a magnet ring 20, 20*, opposite which there are magnet rings 21, 21* secured to the bearing plates 7, 7*. The magnet rings 20, 20*; 21, 21* are axially magnetized and so aligned that in each pair of magnet rings 20; 21; 20*, 21* like poles are opposite one another.The motor 1 is installed in a housing 22 and resiliently mounted therein by means of rubber-elastic elements 23, 23*; 24, 24*. An air filter 25 is disposed between the -housing 22 and the bearing plate 7. The housing 22 is provided at its side adjacent to the spinning rotor 13 with an end 26 which is made conical internally and externally. The tip of the end 26 is rounded, and the rounding which begins intensively at the inside becomes flatter towards the outside. This shape of the tip of the end 26 is adapted to the back of the spinning- rotor 13 which comprises a shallow depression 27 extending from the hub to the outer edge, a gap 28 remaining between the spinning rotor 13 and the housing 26.

In Figure 2, a stator 2 is illustrated with a stack of stator laminations 5 disposed inside the stator body 4. The stator body 4 comprises sixteen cooling-air ducts 8 distributed over the whole periphery of the stack of laminations 5 and extending in the longitudinal direction of the stator body 4.

The mode of operation of the device according to the invention is described as follows: As a result of the rotation of the spinning rotor 13, the air present in the gap 28 is thrown in the radial direction against the outer edge of the spinning rotor 13. The result of this is that a reduced pressure develops in the cavity inside the conical end 26 of the housing 22. In order to equalize the reduced pressure, air flows out of the interior of the motor through the air apertures 18*, 23* of the bearing plate 7*. The effect of this is that a stream of air in the axial direction develops in the motor, particularly in the air ducts 8 in the stator body 4, through the suction action of which the environmental air is drawn in through the filter 25 and the air apertures 18 of the bearing plate 7.

WHAT WE CLAIM IS: 1. An electric motor having an open-end spinning rotor secured to an end of a rotor shaft of the motor, the motor having a stator provided with air ducts which extend over the whole length of the stator, and the motor also comprising a housing having an extension at its end adjacent the spinning rotor, a cavity being present inside the housing extension and a gap remaining between the spinning rotor and the housing, the arrangement being such that, when the motor is running, a flow of air is promoted through the ducts and into said cavity and thence through said gap.

2. An electric motor as claimed in claim 1, in which the width of the gap is 1 to 2mm.

3. An electric motor as claimed in claim 1, in which said housing extension is conical and a radially extending gap remains between said housing end and the back of the spinning rotor.

4. An electric motor as claimed in claim 3, in which the inner face of the conical end is directed towards an inner radius of the back of the spinning rotor.

5. An electric motor as claimed in any preceding claim, in which the air ducts are disposed between a stator body and a stack of stator laminations and are distributed around the whole periphery of the stator.

6. An electric motor as claimed in claim 5, further comprising end bearing plates provided with air apertures equal in number to and aligned with the air ducts of the stator.

7. An electric motor as claimed in claim 6, in which additional air apertures are formed in the bearing plates, directed substantially towards the heads of the stator winding.

8. An electric motor as claimed in any

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. an electric motor with an open-end spinning rotor; and Figure 2 is a cross-section through the stator of the motor illustrated in Figure 1. Figure 1 an electric motor with a stator 2 and a rotor 3 is designated by 1. The stator 2 comprises a stator body 4, a stack of stator laminations 5 with a stator winding 6 and a bearing plate 7, 7* at each end. Cooling ducts 8 extending in the longitudinal direction are provided over the whole length of the stator body 4. The rotor 3 consist of a shaft 9 with a stack of rotor laminations 10 secured to this. The shaft 9 comprises two journals 11, 11 * and a shaft journal 12. The shaft journal 12 serves to receive an open-end spinning rotor 13. The journals 11, 11* form the rotating parts of two radial bearings 14, 14* which are lubricated by gas dynamics and the bearing bushes 15, 15* of which are inserted in the bearing plates 7, 7*. A bearing cover 16 which closes the radial bearing 14 is mounted at the outside of the bearing plate 7.Secured to the side of the bearing plate 7* adjacent to the spinning rotor 13 is a bearing cover 17 which closes the radial bearing 14* and which is provided with a central bore for the passage of the shaft 9. The bearing plates 7, 7* are provided with bores 18, 18*; 19, 19* and the number of bores 18, 18* corresponds to the number of cooling-air ducts 8. In order to achieve as low an air resistance as possible, the cooling-air ducts 8 and the bores 18, 18* are aligned with one another. Disposed at each end of the rotor 3 is a magnet ring 20, 20*, opposite which there are magnet rings 21, 21* secured to the bearing plates 7, 7*. The magnet rings 20, 20*; 21, 21* are axially magnetized and so aligned that in each pair of magnet rings 20; 21; 20*, 21* like poles are opposite one another.The motor 1 is installed in a housing 22 and resiliently mounted therein by means of rubber-elastic elements 23, 23*; 24, 24*. An air filter 25 is disposed between the -housing 22 and the bearing plate 7. The housing 22 is provided at its side adjacent to the spinning rotor 13 with an end 26 which is made conical internally and externally. The tip of the end 26 is rounded, and the rounding which begins intensively at the inside becomes flatter towards the outside. This shape of the tip of the end 26 is adapted to the back of the spinning- rotor 13 which comprises a shallow depression 27 extending from the hub to the outer edge, a gap 28 remaining between the spinning rotor 13 and the housing 26. In Figure 2, a stator 2 is illustrated with a stack of stator laminations 5 disposed inside the stator body 4. The stator body 4 comprises sixteen cooling-air ducts 8 distributed over the whole periphery of the stack of laminations 5 and extending in the longitudinal direction of the stator body 4. The mode of operation of the device according to the invention is described as follows: As a result of the rotation of the spinning rotor 13, the air present in the gap 28 is thrown in the radial direction against the outer edge of the spinning rotor 13. The result of this is that a reduced pressure develops in the cavity inside the conical end 26 of the housing 22. In order to equalize the reduced pressure, air flows out of the interior of the motor through the air apertures 18*, 23* of the bearing plate 7*. The effect of this is that a stream of air in the axial direction develops in the motor, particularly in the air ducts 8 in the stator body 4, through the suction action of which the environmental air is drawn in through the filter 25 and the air apertures 18 of the bearing plate 7. WHAT WE CLAIM IS:

1. An electric motor having an open-end spinning rotor secured to an end of a rotor shaft of the motor, the motor having a stator provided with air ducts which extend over the whole length of the stator, and the motor also comprising a housing having an extension at its end adjacent the spinning rotor, a cavity being present inside the housing extension and a gap remaining between the spinning rotor and the housing, the arrangement being such that, when the motor is running, a flow of air is promoted through the ducts and into said cavity and thence through said gap.

8. An electric motor as claimed in any

preceding claim in which an air filter is disposed at an air inlet to the motor.

9. An electric motor as claimed in claim 1 and substantially as herein described with reference to the accompanying drawings.