GB2055991A - Articulated Support Roller Assembly for Rotor Journals - Google Patents

Abstract

An articulated support roller assembly for rotor journals comprises two sets of rollers (1 0a,b; 20a,b) in each of which the rollers are mounted rotatably on a shaft (12) which includes an eccentric portion (15) between the rollers. The shaft (12) is mounted in a sleeve (16) for rotation or tilting about a transverse axis (11) and the sleeve (16) is mounted rotatably to allow the eccentric portion (15) to be adjusted according to the size of journal to be supported. The construction of the assembly allows for physical articulation of journal during rotation by virtue of mounting of the roller sets about the axes which, in turn, enables cylindrical rollers to be employed thus affording high load capacities. <IMAGE>

Description

SPECIFICATION Articulated Support Roller Assembly for Rotor Journals This invention relates to an articulated support roller assembly for rotor journals, especially for dynamic balancing machines for testing rotors with different journal diameters and with variable included angles between the points of contact of the support rollers with the journals.

Support roller assemblies are commonly used in dynamic balancing machines because they enable rotor journals of various diameters to be accommodated, using simple adjustment means.

Such support roller assemblies must meet two basic requirements in the balancing machine.

There must be clean contact between the journal and the support rollers, and during rotation the bearing must allow for physical articulation. Both conditions are met very simply by support rollers with a cambered outer surface. A disadvantage of these rollers is their relatively low load capacity due to the point contact present. The load capacity can be considerably increased by changing to cylindrical rollers. But in this case the basic requirements necessitates special features.

One type of support roller assembly comprises two cambered rollers with a fixed horizontal spacing. Different journal diameters are allowed for by joint level adjustment. If the cambered rollers are replaced by cylindrical rollers, then with existing constructions the articulation must be provided in the mounting for the support rollers.

This means special support stand (see Carl Schenck AG catalogue no. A 1061 on wattmetric and force-measuring universal dynamic balancing machines).

Starting from this prior art the present invention deals with the problem of providing a support roller assembly for a dynamic balancing machine wherein articulation of the assembly is ensured under high loads.

According to the present invention we provide an articulated support roller assembly for supporting rotors with different journal diameters and with variable included angles between the points of contact of the support rollers with the journals, characterised in that: each support roller comprises two component support rollers mounted on the two spaced portions of a shaft; between said spaced portions there is an eccentric portion which is mounted in a sleeve for angular movement about a transverse axis which is substantially perpendicular to the direction of eccentricity; and the sleeve is rotatably mounted in a carriage of said assembly to enable the angular position of the eccentric portion to be varied.

In one embodiment of the invention the support rollers are cylindrical. Because these rollers are cylindrical a higher load capacity is possible than with cambered rollers, since there is substantially linear contact instead of substantially point contact, without incurring the prior disadvantages of running in on the rotor journals.

In a further embodiment of the invention it is proposed that the rotatable support of the transverse axis is provided by pins. This support of the transverse axis by pins provides positive support in very simple manner. Instead of the pin support in accordance with the invention, the transverse axis may be rotatably supported by supporting the pins in the sleeve on a knife-edge.

This knife-edge support produces a positive and well-defined rotary mobility.

In yet a further aspect of the invention it is proposed that the sleeve in the support roller carriage is mounted in a roller bearing. This roller bearing makes it especially easy to adjust the eccenter in the support direction.

The support roller assembly provided by the invention can not only be used for dynamic balance machines, where it offers the considerable advantage of using cylindrical support rollers in normal balance machine bearing stands, but also for instance as an installation aid in the fitting of turbine blades, to avoid damage to the turbine journal through the rotation.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows schematically an assembly for one side of the support in accordance with one embodiment of the invention; Figure 2 is a section through a support, according to line A-B in Figure 1; Figure 2a is a section through the support, according to line C-D in Figure 2; and Figure 3 shows schematically a knife-edge support in accordance with a second embodiment of the invention.

According to Figure 1 the rotor journal 1 of a rotary body to be tested is supported in a retainer 2 in a support roller assembly as provided by the invention. The support rollers comprise two pairs of cylindrical rollers 1 0a, 1 Ob and 20a, 20b, which are spaced a specific distance apart under the rotation axis of rotor journal 1. Depending on the diameter of the rotor journal 1 there is a variable support angle 4a, 4b between the vertical axis 5 and a line 6a on the pair of cylindrical rollers 1 0a, 1 0b, and a line 6b on the pair of cylindrical rollers 20a, 20b. The entire retainer is vertically adjustable in dependence on the journal diameter by a spindle 3, shown diagrammatically.

This type of adjustment is beneficial when the rotation axis of the rotor in the dynamic balance machine (not shown) has to coincide in height with the drive axis.

Only the operation of the pair of cylindrical rollers 1 Oa and lOb is explained in the following description, since the operation of the pair of rollers 20a, 20b is identical.

In order to permit correct measurement, articulated support is necessary for the rotor journal 1, by means of rotation about a line 7 which connects the axis of rotation 8 of rotor journal 1 with the axis of rotation 9 of an eccentric pin and is shown in more detail in Figure 2, and of rotation about a transverse axis 11 (see Figure 2a) which is perpendicular to line 7. Such articulation for the journal is provided by the two sets of rollers 1 Oa,Ob and 20a, 206 as will be explained in more detail with reference to Figure 2, and hence accurate testing of a rotor is ensured, without the rotary body under investigation being damaged or destroyed by running in of the cylindrical support rollers on the surface of rotor journal 1.

According to Figure 2, the two cylindrical rollers 1 Oa, 1 Oh are supported at a distance apart by two roller bearings 14, 1 4a at the two ends 13, 1 3a of an eccentric shaft 12. The two shaft ends 13, 1 3a (whose axes are depicted by reference numerals 9a) of the eccentric shaft 12 are joined together by an eccentric pin 1 5 (whose axis is depicted by reference numeral 9). By means of rotary pins 17, 1 7a the pin 15 is adapted to rotate about the transverse axis 11 in a sleeve 16.The support roller assembly consisting of two component support rollers 1 Oa, 1 Ob is mounted in the retainer 2 via the sleeve 1 6 and a central roller bearing 18, the axes of said sleeve and said roller bearing being coincident with the axis 9 and hence offset from the axes 9a by the same degree of eccentricity. It will be seen that the mounting of the shaft 12 by the pins 17, 1 7a associated with the rollers 1 Oa, 1 Ob allows the rotor journal to rotate or tilt about the axis 11 associated with the rollers 1 0a, 1 Oh and the mounting of the rollers 20a, 20h allows the rotor journal to rotate or tilt about the axis 7 associated with the rollers 1 0a, 1 Oh.

Figure 3 shows a different rotary support for the transverse axis 11. The eccentric pin is formed as a seat 30 at the side opposite that of maximum eccentricity, with the base of the seat forming the transverse axis 11. In sleeve 1 6 is disposed a knife-edge 31 which ensures that rotor journal 1 is capable of articulation about the transverse axis 11.

If a particularly heavy rotor is mounted with each of its journals in a retainer 2, then depending on the diameter of rotor journal 1 the pair of cylindrical rollers 1 Oa, 1 Oh or 20a, 20h are first rotated for one side of the body being investigated, so that the maximum eccentricity of the pin 1 5 lies in the direction of line 7. This will ensure that the pair of rollers 1 0a, 1 Oh or 20a, 20b through rotation about the pins 17, 1 7a or seat 30, knife-edge 31 lie neatly against the rotor journal 1, but are held fast in the transverse direction thereto.In particular, through the mounting by means of roller bearings in the retainer 2 of the sleeve 1 6 for each support roller consisting of two component support rollers and because of the ready rotation of the roller bearings about their rotation axis there is achieved an easy reaction-free setting of the support rollers to various angles of contact.

If the vertical displacement of the retainer 2 by a spindle 3 within a holder 33 is replaced by a horizntal displacement of the support rollers within the retainer 2, the same benefits are obtained as regards articulation for the journals 1, since the separate mounting of the cylindrical rollers 1 Oa, 1 Ob permits rotation about the line 7 and a rotation about the transverse axis 11 perpendicular to line 7 through the rotary pins 1 7, 1 7a or seat 30 and knife-edge 31.

If instead of a rotor requiring balancing, the support roller assembly is used for example to support a turbine rotor being fitted with blades, the same advantages arise, and in particular that of avoiding damage to the rotor journal through that running in during the fitting.

Claims (6)

Claims

1. An articulated support roller assembly for supporting rotors with different journal diameters and with variable included angles between the points of contact of the support rollers with the journals, characterised in that: each support roller comprises two component support rollers mounted on the two spaced portions of a shaft; between said spaced portions there is an eccentric portion which is mounted in a sleeve for angular movement about a transverse axis which is substantially perpendicular to the direction of eccentricity; and the sleeve is rotatably mounted in a carriage of said assembly to enable the angular position of the eccentric portion to e varied.

2. An assembly as claimed in Claim 1, characterised in that the component support rollers are cylindrical.

3. An assembly as claimed in Claim 1 or 2, characterised in that said eccentric portion is mounted in the sleeve by pins defining said transverse axis.

4. An assembly as claimed in Claim 1 or 2, characterised in that said eccentric portion is mounted in the sleeve by means of a seat and a knife-edge.

5. An assembly as claimed in any one of the preceding claims, characterised in that the sleeve in the support roller carriage is mounted in a roller bearing.

6. An assembly substantially as hereinbefore described with reference to, and as shown in, Figures 1,2 and 2a or Figure 1 as modified by Figure 3 of the accompanying drawings.