CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US National Stage of International Application No. PCT/EP2018/074685 filed 13 Sep. 2018, and claims the benefit thereof. The International Application claims the benefit of German Application No. DE 10 2017 216 463.8 filed 18 Sep. 2017. All of the applications are incorporated by reference herein in their entirety.

FIELD OF INVENTION

The present invention relates to a sealing ring for sealing an annular gap between a shaft and a bearing member which surrounds it, comprising two ring-segment-like sealing ring halves which can be releasably secured to each other and a plurality of sealing tips which are arranged in an axially adjacent manner on the inner peripheral face and which protrude radially inward and which are constructed circumferentially.

BACKGROUND OF INVENTION

Sealing rings of the type mentioned in the introduction are known in the prior art. They are in particular used to seal an annular gap between a shaft and a bearing member which surrounds it and which is arranged or formed in particular on a housing wall which separates a steam chamber and an oil chamber of a steam turbine from each other in order to prevent steam from being able to reach the oil chamber or oil from being able to reach the steam chamber. The sealing ring halves are normally forging blanks of steel, which have partially been subjected to a mechanical processing operation. The sealing tips are provided as separate components which are usually produced from aluminum and which are inserted and caulked in annular grooves formed in the inner peripheral face of the sealing ring. For the use of sealing air, there is formed in at least one sealing ring half by means of drilling a sealing air channel which has a sealing air inlet which is accessible from the outer side for connecting a sealing air device and a sealing air outlet which opens in the region of the sealing tips in the inner peripheral face. Another channel which is produced by means of drilling and which leads from the inner peripheral face to a side face of a sealing ring half forms a pressure measurement channel, to which a pressure measurement device can be connected in order to detect the current pressure of the sealing air and to ensure an optimum pressure adjustment. In order to discharge oil which accumulates between the sealing tips, the sealing ring is further provided with an oil return channel which extends from the inner peripheral face in the direction of a side face of the corresponding sealing ring half and which was also introduced using a drilling method.

A disadvantage of the above-described known sealing ring is that it has a complex and production-intensive construction with many individual components and a high inherent weight. In addition, it is desirable to further improve the functional design of the known sealing ring.

SUMMARY OF INVENTION

Against this background, an object of the present invention is to provide a sealing ring of the type mentioned in the introduction with an alternative structure which at least partially overcomes the disadvantages mentioned above.

In order to achieve this object, the present invention provides a sealing ring of the type mentioned in the introduction, which is characterized in that the sealing tips are constructed in one piece with the sealing ring halves. As a result of such an integral construction, the sealing ring according to the invention has a small number of individual components. Accordingly, the sealing ring according to the invention can be produced and assembled in a simple manner, which involves low costs. Consequently, the present invention relates to a sealing ring for sealing an annular gap between a shaft and a bearing member which surrounds it, comprising two ring-segment-like sealing ring halves and a plurality of sealing tips which are arranged in an axially adjacent manner on the inner peripheral face and which protrude radially inward and which are constructed circumferentially, wherein the sealing tips are constructed in once piece with the sealing ring halves.

Preferably, the sealing ring halves are provided with a sealing air channel system which is produced during the additive production and which has a sealing air inlet channel, at least one sealing air distribution channel which is connected thereto, and a plurality of sealing air outlet channels which are connected to the sealing air distribution channel and which open in the region of the sealing tips in the inner peripheral face. The significant advantage of such a sealing air channel system is that the sealing air can be introduced via the sealing air distribution channel which can be freely configured as a result of the additive production without additional technical production complexity at extremely different peripheral positions in the region of the sealing tips in the inner peripheral face of the sealing ring, whereby the sealing action which is involved with the sealing ring can be optimized as a result of optimized sealing air supply.

According to an embodiment of the present invention, the sealing ring halves and accordingly the sealing tips are produced from aluminum, which first and foremost involves a good sealing action and a very low inherent weight. Furthermore, aluminum is sufficiently soft to prevent rubbing damage in the event of contact with the shafts.

Advantageously, side faces of the sealing ring halves are provided with reinforcement ribs, which enables a comparatively thin-walled construction of the sealing ring halves and consequently a further reduction of the inherent weight and the material costs. The reinforcement ribs may in particular extend in a radial direction. Advantageously, however, reinforcement ribs which extend in a peripheral direction are also provided.

According to an embodiment of the present invention, the sealing ring halves are produced using an additive production method, in particular from a powdered starting material. As an additive production method, selective laser melting (SLM) may be mentioned here by way of example. The use of an additive production method has the advantage that there are only a small number of limitations with regard to the design of the sealing ring. Accordingly, the functionality of the sealing ring according to the invention can also be optimized.

In particular, the sealing air distribution channel is constructed circumferentially and the sealing air outlet channels are arranged in a state distributed in a substantially uniform manner over the periphery of the sealing ring. Accordingly, there is a particularly uniform action of sealing air on the intermediate spaces present between the sealing tips and the shaft.

Preferably, at least one sealing ring half is provided with a pressure measurement channel which is produced during the additive production and which is connected to the sealing air channel system and which is provided to connect the sealing air system to a pressure measurement device, wherein the pressure measurement channel opens in particular in the sealing air distribution channel, whereby a particularly simple construction is achieved. Using the pressure measurement device, the sealing air supply can be checked, adjusted and/or also controlled.

According to an embodiment of the present invention, at least one sealing ring half is provided with at least one oil return channel which is produced during the additive production and which extends from the inner peripheral face in the direction of a side face of the sealing ring half. Via such an oil return channel, oil which has accumulated between the sealing tips can be discharged.

Preferably, a plurality of oil return channels are provided, wherein at least one oil return channel terminates shortly before the side face of the sealing ring half. The oil return channel which terminates shortly before the side face can then be selectively drilled if a larger oil return capacity should be required. In this manner, the sealing ring according to the invention can be adapted in a flexible manner to different requirements on the oil return capacity. In particular, there is provided on the side face a drill attachment which marks a position for positioning a drilling tool in order starting from the side face to drill an access to the oil return channel which is still closed. Such a drill attachment facilitates the drilling processing operation.

Furthermore, in order to solve the problem set out in the introduction, the present invention provides a method for producing a sealing ring according to the invention, comprising the steps of: producing the sealing ring halves using an additive production method, in particular with the sealing air channel system being formed and/or the pressure measurement channel and/or one of or the oil return channels; milling the parting joints of the sealing ring halves; assembling the sealing ring by clamping the sealing ring halves and mechanically processing the outer peripheral face and the inner peripheral face of the sealing ring with the sealing tips being formed, in particular using a turning and/or grinding method.

According to an embodiment of the method according to the invention, an access to an oil return channel which is produced in the context of the additive production and/or to a pressure measurement channel which is produced in the context of the additive production is further drilled.

