RU2303143C1 - Rotary machine resilient-damping support - Google Patents

Abstract

FIELD: mechanical engineering; rotary machines.

SUBSTANCE: invention relates to design of variable pliability resilient supports of rotary machines. Proposed resilient-damping support of turbomachine contains bearing, stator member and shell secured on outer race of bearing and connected with stator member by means of split bushing and thus forming damping space with stator member. Stator member and shell are provided with steps and are installed relative to each other for engagement by their conical mounting surfaces. Split bushing is provided with slots tilted relative to longitudinal axis of support. Invention makes it possible to change pliability of support by changing axial load directly in process of operation of rotary machine, thus changing amplitude frequency characteristic of rotor and providing constant operation of rotor at nocritical speeds.

EFFECT: reduced vibrations of rotary machine and axial dimensions of support.

Description

The invention relates to the field of engineering, and in particular to the design of the elastic supports of rotary machines with variable flexibility.

Known elastic damper support of the rotor of a turbomachine, comprising a bearing, a stator element and a shell fixed to the outer ring of the bearing connected to the stator element by means of a split sleeve and forming a damping cavity with it, the stator element and the shell are made with ledges and are mounted relative to each other with the possibility of contacting on the landing surface of the ledges (Patent RU No. 2265728, IPC F01D 25/16, 12/10/2005).

In a known support, the shell is in contact with the stator element along the surface of the end ledges in a plane perpendicular to the longitudinal axis of the rotor. This design does not allow to transfer the radial load from the bearing to the stator element directly through the shell, and not through the split sleeve, and therefore does not provide for the possibility of directive changes in the ductility of the support necessary in case of engine operation in the region of critical rotor rotational frequencies in order to reduce dynamic deflections of rotors and vibration support loads.

In addition, the known support has substantial dimensions in the axial direction.

The objective of the invention is to reduce the vibration of the turbomachine by changing the flexibility of the elastic damper support while reducing the dimensions of the support.

The problem is solved in that in the elastic damper support of a rotor machine containing a bearing, a stator element and a shell secured to the outer ring of the bearing connected to the stator element by means of a split sleeve and forming a damping cavity with it, the stator element and the shell are made with ledges and mounted relative to each other friend with the possibility of contacting on the landing surfaces of the ledges, the landing surfaces of the ledges are made conical, and a split sleeve is made with slots, inclined tnositelno the longitudinal axis of the support.

The implementation of the landing surfaces of the ledges of the shell and the stator element conical allows you to transfer the radial load from the bearing to the stator element directly through the shell, bypassing the split sleeve, providing, if necessary, the ability to change the flexibility of the support directly during operation of the rotor machine, which allows you to change the value of the critical rotor speed and reduce the vibration of the rotor machine when operating in the region of critical rotor speeds.

The execution of the split sleeve with slots inclined relative to the longitudinal axis of the support ensures the operation of the sleeve as a spring in the axial direction, which, when the axial load increases, will ensure contacting the ledges of the shell and the stator element along the conical surface and will allow changing the flexibility of the support. In addition, this allows to reduce the dimensions of the support in the axial direction.

The invention is illustrated graphically, in which Fig. 1 shows an elastic damper support (longitudinal section), and in Fig. 2 is a view A of Fig. 1.

The elastic-damper support of the rotor machine contains a ball bearing 1, on the outer ring of which a shell 2 is fixed, connected to the stator element 3 by means of a split sleeve 4. The sleeve 4 is made with a series of inclined slots 5 forming beams 6. The shell 2 forms a damping cavity 7 with the stator element 3, limited by seals 8 and 9. The shell 2 and the stator element 3 are made with ledges 10 and 11 and are installed with the possibility of contacting each other along the conical surfaces of the ledges 10 and 11.

The support works as follows.

When the rotor rotates with a non-critical speed, there is no contact of the stator element 3 with the shell 2 along the conical surfaces of the steps 10, 11, and the radial load from the bearing 1 to the stator element 3 is transmitted through the split sleeve 4.

When the rotor speed reaches the critical speed and, as a result, the vibrations of the turbomachine increase, the axial load perceived by the ball bearing 1 is changed. The axial force displaces the rotor, resulting in the sleeve 4 acting as a spring (due to the inclined slots 5 of the split sleeve 4, deformation 6), begins to compress the surface of the ledge 11 of the shell 2 to the surface of the ledge 10 of the stator element 3. The shell 2 and the stator element 3 begin to contact each other along the surfaces of the ledges 10 and 11, and the load from the outer ring of the ball bearing 1 begins to be transmitted to the stator element directly through the shell 2, bypassing the split sleeve 4. Thus, the compliance of the support changes (the support becomes elastic rigid). This leads to a change in the amplitude-frequency characteristic (AFC) of the rotor and, as a result, to a change in the critical rotational speed of the rotor.

When the rotor passes the zone of critical rotational speeds, the axial load is reduced. In this case, the beams 6 of the sleeve 4 are straightened, and a gap is formed between the steps 10 and 11, after which the radial load from the outer ring of the ball bearing 1 will be transmitted through the split sleeve 4. Thus, the suppleness of the support will increase to its original value.

It is possible that the support initially works as rigid, i.e. the axial force provides contact of the stator element 3 with the shell 2 along the surface of the ledges 10 and 11. In this case, when the rotor reaches the critical speed, the axial force is reduced, which leads to the clearance of the ledges 10 and 11 and increase the compliance of the support. Similar to the above, there is a change in the frequency response of the rotor and a decrease in vibration of the turbomachine.

The invention allows by changing the axial load to change the flexibility of the support directly during operation of the rotor machine, thereby changing the frequency response of the rotor, ensuring constant operation of the rotor at non-critical frequencies of its rotation and reducing vibration of the rotor machine, as well as to reduce the axial dimensions of the support.

Claims (1)

The elastic damper support of the turbomachine, comprising a bearing, a stator element and a shell fixed to the outer ring of the bearing, connected to the stator element by means of a split sleeve and forming a damping cavity with it, the stator element and the shell being made with ledges and mounted relative to each other with the possibility of contacting along the seating surfaces ledges, characterized in that the landing surfaces of the ledges are made conical, and the split sleeve is provided with slots made oblique and the longitudinal axis of the support.

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