WO2014000796A1

WO2014000796A1 - Machine arrangement

Info

Publication number: WO2014000796A1
Application number: PCT/EP2012/062532
Authority: WO
Inventors: Gilbert PETERS; Jeroen Wensing; Nijs VAN DER MEI
Original assignee: Aktiebolaget Skf
Priority date: 2012-06-28
Filing date: 2012-06-28
Publication date: 2014-01-03

Abstract

The invention relates to a machine arrangement (1) comprising a housing element (2) and a rotor element (3), wherein the rotor element (3) is rotatable supported in the housing element (2) by at least one bearing (4), wherein the rotor element (3) can rotate around an axis (a), wherein the at least one bearing (4) has an inner ring (5) and an outer ring (6), wherein one of the bearing rings (5, 6) is connected with the housing element (2) by means of an carrier element (7), wherein the carrier element (7) has a reception section (8) for fixing one of the bearing rings (5, 6) and wherein the carrier element (7) has a connection section (9) for fixing the carrier element (7) with the housing element (2). To improve the rotor dynamic behavior of a high speed machine the invention proposes that the carrier element (7) has a first part (10) which comprises the reception section (8) and has a second part (11) which comprises the connection section (9), wherein an elastic material (12) is arranged between the first and second part (10, 11), so that both parts (10, 11) have no direct contact with another.

Description

Machine Arrangement

Technical Field

The invention relates to a machine arrangement comprising a housing element and a rotor element, wherein the rotor element is rotatable supported in the housing element by at least one bearing, wherein the rotor element can rotate around an axis, wherein the at least one bearing has an inner ring and an outer ring, wherein one of the bearing rings is connected with the housing element by means of an carrier element, wherein the carrier element has a reception section for fixing one of the bearing rings and wherein the carrier element has a connection section for fixing the carrier element with the housing element.

Background

Machine arrangements of this kind are well known in the art. They are employed for example in an electric machine like an electric compressor or a turbine generator. Here, a rotor is supported by bearings relatively to a housing. In those machines the rotor is rotating during regular use. The rotor does not only maintain a certain constant revolution speed. Also, the rotary speed of the rotor varies. When starting the machine the rotor has to be driven from a revolution speed of zero to the required number of revolutions. Thus, the rotor will have to passage critical rotation frequencies where vibration will be excited. Due to the design of the machine is can be that during transition of critical frequencies, i. e. when the rotor passes a rotational speed which is a resonance frequency of the rotor system, vibrations reach critical magnitudes which can damage the machine arrangement and which at least cause loud noises.

It is known in the art to employ elastic O-rings or oil squeeze film dampers to improve the dynamical behavior of the arrangement when passing critical rotations speeds of the rotor.

Thus, it is an o bj e c t of the present invention to propose a machine arrangement which allows a silent and safe passage of critical frequencies. So, vibrations and noises should be reduced which can occur during operation of the machine arrangement.

Summary of the invention A s o l u t i o n according to the invention is characterized in that the carrier element has a first part which comprises the reception section and has a second part which comprises the connection section, wherein an elastic material is arranged between the first and second part, so that both parts have no direct contact with another. The elastic material can have a ring shape. It has preferably a flat structure; preferably the thickness of the elastic material is substantial constant. A plane of the elastic material, especially of the ring, is extending preferably perpendicular to the axis of the rotor, i. e. in radial direction.

The second part of the carrier element can have a ring shape which is substantially covered at one face side with the elastic material. This cover can be interrupted by cut-outs. More specifically the elastic material can have cutouts for the passage of a fixation element, by which the second part is fixed to the housing element. Those cut-outs can have a circular shape, wherein a plurality of cut-outs is preferably distributed equidistantly around the circumference of the second part.

The fixation elements are preferably screws or bolts.

The second part of the carrier element can have a radial extending ring section and an adjacent hollow cylindrical section. Preferably, the hollow cylindrical section forms or bears the reception section.

The first part and the second part of the carrier element are preferably made from metal, especially from sheet metal. The elastic material is preferably a polymer material or a rubber material.

A preferred embodiment of the invention has two carrier elements supporting two bearings, wherein the two carrier elements are arranged at two axially distanced locations of the housing element. The bearing is preferably a roller bearing.

The machine arrangement is preferably a part of an electrical machine, especially of an electric compressor or of a turbine generator.

Accordingly and preferably a metal end cap (carrier element) is mounted on the stator housing (housing element) of an electrical machine which has an elastic layer perpendicular to the rotor axis in order to create shear.

This provides a predefined stiffness and damping to the system, in particular when the elastic layer is made from polymer or rubber material.

Preferably, the bearing end cap consists of two metal parts separated by the elastic layer. Only one metal part is fixed to the stator housing. The end cap also contains a roller bearing respectively a reception section for the same to allow transfer of loads of the rotor.

Thus, the invention proposes a flexible end cap support for a (roller) bearing system. The flexible end cap arrangement has at least one elastic layer, which is designed to provide and tune the optimum rotor dynamic behavior of a high speed machine, especially of an electrical machine like an electric compressor or a turbine generator. By the proposed design a secure silent and safe passage of critical frequencies of the rotor is possible which causes a reducing of noises and vibration in the arrangement.

Due to the concept of dividing the carrier element into two parts - separated by the elastic material - a dual mass system is created for each end-cap that allows for vibration isolation of critical modes. Thus, not the dissipation (damping) of vibration energy is primary but the shifting of the critical frequencies into another frequency region. In other words, the proposed design moves the critical frequencies using the two-mass concept (or dummy mass) and thus achieves vibration isolation; the energy of vibration is not primary dissipated but moved to another frequency region.

As a very beneficial aspect the elastic material or layer is extending perpendicular to the axial direction of the rotor to generate shear deformation in the layer under radial shaft motion.

The proposed end cap design, i. e. the design of the carrier element, is very compact and provides stiffness and damping at the same time with well- defined tunable parameters.

Brief description of the drawings

The drawing shows an embodiment of the invention. The only figure shows a radial cross section through a machine arrangement which is an electrical machine.

Detailed description of the invention

In the figure a machine arrangement 1 is shown which is for example an electric compressor or turbine generator. A rotor element 3 is arranged in a housing element 2; the rotor element 3 rotates around an axis a. For supporting the rotor element 3 in the housing element 2 two bearings 4 are employed. Both bearings 4 have an inner ring 5 and an outer ring 6 which are referred to only schematically. At least one of the bearings 4 has radial and axial bearing properties.

The bearings 4 are supported relatively to the housing element 2 by means of carrier elements 7. Two carrier elements 7 are located at two axial end sides of the housing element 2. The carrier element 7 has a reception section 8 which is designed to hold the outer ring 6 of the bearing 4 firmly. Furthermore, the carrier element 7 has a connection section 9 by which the carrier element 7 is fixed to the housing element 2. For fixation fixation elements 15 are used which are presently screws.

Essentially, the carrier element 7 has a first part 10 which comprises the reception section 8. Furthermore, it has a second part 11 which comprises the connection section 9. An elastic material 12 is arranged between the first and second part 10 and 11, so that both parts 10 and 11 have no direct contact with another. The elastic material can be a polymer of rubber part and has a substantial ring shape. Also the second part 11 is substantial ring shaped. Thus, the second part 11 is covered at one of its face sides 13 with the elastic material 12.

The reception section 8 is realized in a hollow cylindrical section 17 of the carrier element 7 and more specifically in the first part 10 of the same. Adjacent to the hollow cylindrical section 17 a ring section 16 is arranged which extends radially outwards. In the outer region of the ring section 16 the elastic material 12 is arranged. As can be seen a kind of sandwich structure is given in the radial outer region of the carrier element 7, i. e. the elastic material 12 is arranged between the ring section 16 of the first part 10 and the second part 11 of the carrier element 7.

The connection between the elastic material 12 and the metal parts 10 and 11 is done in a manner which is basically known to the man skilled in the art.

Preferably, a vulcanization process can be employed in the case that the elastic material 12 is rubber. In the case of a polymer it is possible to establish the connection between the parts 10 and 11 by injection moulding, wherein the parts 10, 11 are inserted into an injection moulding tool and the polymer material is then injected into the mould to produce the layer 12. In this case the connection is produced in situ.

Of course also other techniques are possible, e. g. glueing of the elastic material 12.

The elastic material 12 has a constant thickness d which is properly dimensioned to allow a sufficient vibration decoupling effect but to be also able to transmit sufficiently forces from the rotor element 3 to the housing element 3.

As can be seen (circular shaped) cut-outs 14 are arranged in the elastic material 12 as well as in the ring section 16. This serves to allow the fixation elements (screws) 15 to pass the ring section 16 as well as the elastic material 12 and to firmly connect the second part 11 with the housing element 2. Reference Numerals:

1 Machine arrangement

2 Housing element

3 Rotor element

4 Bearing

5 Inner ring

6 Outer ring

7 Carrier element

8 Reception section

9 Connection section

10 First part of the carrier element

11 Second part of the carrier element

12 Elastic material

13 Face side

14 Cut-out

15 Fixation element (screw / bolt)

16 Ring section

17 Hollow cylindrical section

a Axis

d Thickness

Claims

Patent Claims:

1. Machine arrangement (1) comprising a housing element (2) and a rotor element (3), wherein the rotor element (3) is rotatable supported in the housing element (2) by at least one bearing (4), wherein the rotor element (3) can rotate around an axis (a), wherein the at least one bearing (4) has an inner ring (5) and an outer ring (6), wherein one of the bearing rings (5, 6) is connected with the housing element (2) by means of an carrier element (7), wherein the carrier element (7) has a reception section (8) for fixing one of the bearing rings (5, 6) and wherein the carrier element (7) has a connection section (9) for fixing the carrier element (7) with the housing element (2), characterized in that the carrier element (7) has a first part (10) which comprises the reception section (8) and has a second part (1 1) which comprises the connection section (9), wherein an elastic material (12) is arranged between the first and second part (10, 11), so that both parts (10, 11) have no direct contact with another.

2. Machine arrangement according to claim 1 , characterized in that the elastic material (12) has a ring shape, wherein the elastic material (12) has preferably a flat structure with a substantial constant thickness (d).

3. Machine arrangement according to claim 1 or 2, characterized in that a plane of the elastic material, especially of the ring, is extending perpendicular to the axis (a).

4. Machine arrangement according to one of claims 1 to 3, characterized in that the second part (11) of the carrier element (7) has a ring shape which is substantially covered at one face side (13) with the elastic material (12).

5. Machine arrangement according to claim 4, characterized in that the elastic material (12) has cut-outs (14) for the passage of a fixation element (15), by which the second part (11) is fixed to the housing element (2).

6. Machine arrangement according to claim 5, characterized in that the cutouts (14) have a circular shape, wherein a plurality of cut-outs (14) are preferably distributed equidistantly around the circumference of the second part (11).

7. Machine arrangement according to claim 5 or 6, characterized in that the fixation elements (15) are screws.

Machine arrangement according to one of claims 1 to 7, characterized in that the second part (1 1) of the carrier element (7) has a radial extending ring section (16) and an adjacent hollow cylindrical section (17).

Machine arrangement according to claim 8, characterized in that the hollow cylindrical section (17) forms or bears the reception section (8).

Machine arrangement according to one of claims 1 to 9, characterized in that the first part (10) and the second part (1 1) of the carrier element (7) are made from metal, especially from sheet metal.

11. Machine arrangement according to one of claims 1 to 10, characterized in that the elastic material (12) is a polymer material.

12. Machine arrangement according to one of claims 1 to 10, characterized in that the elastic material (12) is a rubber material.

13. Machine arrangement according to one of claims 1 to 12, characterized in that two carrier elements (7) supporting two bearings (4) are arranged at two axially distanced locations of the housing element (2). Machine arrangement according to one of claims 1 to 13, characterized in that the bearing (4) is a roller bearing.

Machine arrangement according to one of claims 1 to 14, characterized in that the machine arrangement is a part of an electrical machine, especially of an electric compressor or of a turbine generator.