Patent Application
20240318580
The present disclosure relates to a turbine housing clamping connection for a turbine, and to a turbine comprising a turbine housing clamping connection.
Turbines, in particular radial-flow turbines, having a bearing housing, a turbine housing, a heat shield and a nozzle ring are known from the prior art. Typically in this case either the heat shield is clamped axially between the bearing housing and the nozzle ring and radially by the turbine housing, or the nozzle ring is clamped axially by the bearing housing and radially by the turbine housing. EP 1 428 983 A1 describes, for example, an exhaust gas turbine housing.
In applications with frequently changing load conditions, and in particular in the case of high load conditions, the turbine may exhibit signs of wear. This fatigue wear occurs in particular on the bearing housing and may in turn cause further problems.
In view of the above, there is a need for an improved nozzle ring for a turbine stage which can mitigate the above-mentioned problems and, in particular, can be easily adapted to the respective requirements of a turbocharger and/or an engine application.
This object is achieved at least in part by a turbine housing clamping connection for a turbine as claimed in claim 1. Furthermore, the object is achieved by a turbine comprising a turbine housing clamping connection as claimed in claim 14 and by the use of a turbine housing clamping connection as claimed in claim 15. Further embodiments, modifications and improvements are found in the following description and the appended claims.
According to one embodiment, a turbine housing clamping connection for a turbine, in particular a radial exhaust gas turbine, is provided. The turbine housing clamping connection has a bearing housing, a turbine housing and a clamping component comprising a clamping flange clamped between a bearing housing clamping portion of the bearing housing and a turbine housing clamping portion of the turbine housing. The clamping flange has a bearing-housing-side clamping surface comprising a convexly curved clamping surface region. Furthermore, the convexly curved clamping surface region defines a minimum radius of curvature. A ratio of the minimum radius of curvature to an inner radius of the clamping surface is at least 0.1 and/or at most 10, and preferably at least 0.5 and/or at most 2.0, and more preferably at least 1.0 and/or at most 1.4.
The invention is explained in greater detail below with reference to embodiments which are not intended to restrict the scope of protection defined by the claims.
The accompanying drawings illustrate embodiments and, together with the description, serve to explain the principles of the invention. The elements of the drawings are shown relative to one other and are not necessarily true to scale. Similar reference signs denote correspondingly similar parts.
In the figures:
In the following detailed description, reference is made to the accompanying drawings, which form a part hereof and show, by way of illustration, specific embodiments in which the invention may be implemented. It is to be understood that other embodiments may be used, and structural or logical modifications may be made, without departing from the scope of protection of the present invention. The following detailed description is therefore not to be interpreted in a limiting manner, and the scope of protection of the present invention is determined by the appended claims. The embodiments described use specific language which is not to be interpreted as limiting the scope of protection of the appended claims.
As depicted in the embodiments in
According to an embodiment, the clamping component is a heat shield 130.
According to a further embodiment, the clamping component 130, 140 is a nozzle ring 140. In
The clamping flange 137, 147 of the clamping component, for instance at least one of the clamping components 130, 140 shown in
According to a general aspect, the clamping component 130, 140 (and also the bearing housing and the turbine housing) is constructed so as to completely surround a turbine shaft. The clamping component 130, 140 may have a substantially disk-shaped cross section. In this case, the clamping flange is preferably clamped over the entire circumference of the clamping component 130, 140 between the bearing housing clamping portion of the bearing housing 110 and the turbine housing clamping portion of the turbine housing 120.
The convexly curved clamping surface region 132 of the bearing-housing-side clamping surface is preferably arranged in a radially outer manner on the clamping flange 137.
In this case, the convexly curved clamping surface region 132 defines a minimum radius RK of curvature. The radius RK of curvature is denoted by a double-headed arrow in
In this case, a radially inner end 133 of the convexly curved clamping surface region 132 may correspond, on the bearing housing side, to an axially outermost point of the convexly curved clamping surface region 132, as shown for example in
In other words, an axially outermost point (as viewed from the bearing housing side) of the osculating circle segment UK may correspond to a radially inner end 133, wherein the clamping surface region extends away from the bearing housing 110, as viewed from the radially inner end 133 to a radially outer end 135. Alternatively, an axially outermost point of the osculating circle segment UK may also be arranged at any desired location along the osculating circle segment UK.
The bearing-housing-side clamping surface 131 may have one or more clamping surface regions which are clamped by the bearing housing clamping portion. Typically, the bearing-housing-side clamping surface defines at least one further clamping surface region. The further clamping surface region is preferably a radially inner clamping surface region, and/or a radially outermost clamping surface region. For example,
The radially inner clamping surface region and/or the radially outermost clamping surface region are preferably not convexly curved, but are formed so as to be substantially flat. For example, the radially inner clamping surface region and/or the radially outermost clamping surface region may, however, also have a convexly shaped portion with a radius of curvature which is smaller than the minimum radius of curvature of the convexly curved clamping surface region 132.
In alternative configurations, the bearing-housing-side clamping surface does not have a radially outermost clamping surface region. In this case, the convexly curved (radially outer) clamping surface region extends to the radial end 134 of the bearing-housing-side clamping surface.
The convexly curved clamping surface region is preferably a radially outer clamping surface region of the bearing-housing-side clamping surface. The bearing-housing-side clamping surface may further comprise the radially inner clamping surface region. The convexly curved (radially outer) clamping surface region 132 adjoins the radially inner clamping surface region in a continuous manner, preferably a tangentially continuous manner. For example,
Additionally or alternatively, the bearing-housing-side clamping surface may comprise the radially outermost clamping surface region. The radially outermost clamping surface region may adjoin the convexly curved (radially outer) clamping surface region in a continuous manner, preferably a tangentially continuous manner. This preferably results in a smooth, continuous transition between the convexly curved (radially outer) clamping surface region and the radially outermost clamping surface region. The radially outermost clamping surface region may be formed so as to be substantially flat (as viewed in the axial direction), and may deviate slightly or gently from a flat course in the region of a transition to the convexly curved clamping surface region.
An inner radius DR of the clamping surface is in this case the radius measured from the centroid of the turbine shaft or the centroid of a cross-sectional view of the clamping component. According to the present disclosure, the inner radius DR is the radius measured in the idle state of the turbine housing clamping connection or turbine. For example, under high load conditions, heating may cause a slight expansion and thus a change in the inner radius DR. All characteristics or parameters disclosed herein are values measured in the idle state unless expressly described otherwise.
The inner radius DR is the radius of the convexly curved clamping surface region, preferably the radius at the axially outermost point, as viewed from the bearing housing side, of the curved clamping surface region. In some configurations, the inner radius DR is the radius of the radially inner end 133. In other words, the inner radius DR is preferably the radial distance between the centroid of the turbine shaft and the axially outermost point, as viewed from the bearing housing side, of the curved clamping surface region.
The inventors have identified that in turbine housing clamping connections known from the prior art, asymmetric heating between the bearing housing 110 and the clamping component 130, 140, for example a heat shield, may cause the contact surface between the bearing housing and the clamping component to tilt or tip. For example, the bearing housing may consist of the alloy GGG40, and the clamping component may consist of a higher-alloy, generally heat-resistant, material. The clamping component is typically arranged in a fluid channel and thus becomes hotter than the contact point between the bearing housing and the clamping component. The clamping component heats up more rapidly during operation and typically has a greater coefficient of thermal expansion than the bearing housing. This asymmetric heat input causes the clamping component to move relative to the bearing housing during the heating process and under changing load conditions.
The tipping of the contact surface between the bearing housing and the clamping component in turbine housing clamping connections known from the prior art gives rise to high local bearing stress. As a result of the relative movement, this highly loaded point migrates across the contact surface of the bearing housing 110 (of the bearing housing clamping portion) and causes fatigue wear, which may in turn lead to further problems, such as loss of bolt preload or gas leakage.
The turbine housing clamping connection according to embodiments of the present disclosure has a clamping component 130 comprising the convexly curved clamping surface region 132, which considerably reduces wear on the components, and in particular on the bearing housing. Providing the clamping surface region with a slightly or gently convexly curved shape makes it is possible to ensure the clamping surface is supported over a wide area and high local bearing stress is thus prevented, not only in a “hot” state (i.e., under high load conditions or at high temperatures of a fluid in the radial-flow turbine), but also in the states throughout the heating process, as well as in an idle state. Due to the slightly convexly curved shape, an extended contact surface is provided in both the stationary and transient operating states between the bearing housing clamping portion and the bearing-housing-side clamping surface, resulting in a substantial reduction in wear. The convexly curved clamping surface region configured according to the invention makes it possible for the clamping component to tilt slightly during the heating process without resulting in excessive local contact stress, compared to a cold state, in a contact region between the bearing housing clamping portion and the bearing-housing-side clamping surface.
The inventors have further identified that high local bearing stress and the fatigue wear connected therewith can be countered most effectively when the ratio of the minimum radius of curvature to an inner radius of the clamping surface is at least 0.1 and/or at most 10, preferably at least 0.5 and/or at most 2.0, and more preferably at least 1.0 and/or at most 1.4.
According to embodiments of the present disclosure, the curved clamping surface region is constructed to guarantee substantially surface-to-surface contact with the bearing housing clamping portion when the clamping flange tilts. In this case, “tilting” means that a radially inner part of the clamping flange is moved axially away from the bearing housing relative to a radially outer part of the clamping flange and/or is moved (tilts) in the direction of the turbine housing. Tilting may involve a rolling and/or shifting movement of the clamping surface. This means that tilting may also take place without a fixed tilting point on the clamping surface. In this case, “surface-to-surface contact” is not necessarily to be understood as contact over the entire surface between the bearing housing clamping portion and the convexly curved clamping surface region. By constructing the curved clamping surface region to ensure surface-to-surface contact with the bearing housing clamping portion, high local bearing pressure is still prevented. The convexly curved clamping surface region is thus constructed to counter wear on the bearing housing.
According to an aspect, an axial offset t between an axially outermost point of the curved clamping surface region 132 on the bearing housing side and the radially outer end 135 of the curved clamping surface region 132 is at least 0.01 mm and/or at most 0.5 mm, preferably 0.02 mm and/or at most 0.2 mm, and more preferably at least 0.03 mm and/or at most 0.1 mm. In
Additionally or alternatively, an axial offset t between the radially inner end 133 of the curved clamping surface region 132 and the radially outer end 135 of the curved clamping surface region 132 is at least 0.01 mm and/or at most 0.5 mm, preferably 0.02 mm and/or at most 0.2 mm, and more preferably at least 0.03 mm and/or at most 0.1 mm. The radially outer end 135 is axially offset toward the turbine housing due to the convex curvature. The radially inner end 133 is in some configurations axially offset toward the bearing housing (as shown for example in
In an aspect, the minimum radius RK of curvature of the convexly curved clamping surface region 132 is at least 20 mm and/or at most 1000 mm, and preferably at least 50 mm and/or at most 500 mm, more preferably 100 mm and/or at most 200 mm, and most preferably at least 140 mm and/or at most 160 mm. In an exemplary configuration, the minimum radius RK of curvature is 150 mm. A radius RK of curvature in the aforementioned range guarantees that the curvature deviates sufficiently from a flat clamping surface region and at the same time is not excessively curved. Additionally or alternatively, the inner radius DR of the clamping surface or the convexly curved clamping surface region 132 may be at least 20 mm and/or at most 300 mm, preferably at least 100 and/or at most 140 mm.
The curved clamping surface region 132 may have a radial extent of at least 0.5 mm and/or at most 10 mm. Preferably, the curved clamping surface region 132 has a radial extent of at least 3 mm and/or at most 6 mm. In embodiments in which the clamping surface comprises the radially outermost clamping surface region, a radial distance between the radially inner end 133 of the curved clamping surface region 132 and the radial end 134 of the bearing-housing-side clamping surface may be at least 2 mm and/or at most 20 mm, preferably at least 6 mm and/or at most 10 mm.
A ratio of the radial extent of the curved clamping surface region 132 to the inner radius DR of the clamping surface or of the convexly curved clamping surface region 132 may be at least 0.005 and/or at most 0.1, preferably at least 0.02 and/or at most 0.05.
In a preferred embodiment, a ratio of the axial offset t to the radial extent of the curved clamping surface region 132 is at least 5*10−3 and/or at most 0.02, and preferably at least 8*10−3 and/or at most 0.015. A ratio in the aforementioned range guarantees that the curvature deviates sufficiently from a flat clamping surface region and at the same time is not excessively curved.
The curved clamping surface region 132, and in particular the radially inner end 133 and the radially outer end 135 of the convexly curved clamping surface region 132, define(s) the osculating circle segment UK. A central angle alpha α of the osculating circle segment UK may be at least 0.5° and/or at most 4°, preferably at least 1.2° and/or at most 2.0°.
Additionally or alternatively, a ratio of the axial offset t and the radius RK of curvature may be at least 2*10−4 and/or at most 2*10−3, and preferably at least 3*10−4 and/or at most 8*10−4.
A tangential angle of the curved clamping surface region 132 relative to the radial direction may be at least 0.5° and/or at most 4°, preferably at least 1.2° and/or at most 2.0°. Furthermore, in a cross-sectional view containing the turbine shaft, at least one tangential angle of the curved clamping surface region 132 relative to the radial direction may be at least 0.5°, preferably at least 1.2°, and/or all tangential angles of the curved clamping surface region 132 relative to the radial direction may be at most 4°, preferably at most 2.0°.
The other sides of the clamping flange, for example a turbine-housing-side clamping surface, are not specifically limited according to the present disclosure, and may be formed in accordance with clamping flanges known in the prior art.
According to an aspect, a turbine, preferably a radial-flow turbine 200, 300, is provided. The turbine has the turbine housing clamping connection according to any one of the embodiments described herein. In a configuration, the turbine is a power turbine and/or an exhaust gas turbine. For example, the exhaust gas turbine may be an exhaust turbocharger turbine. According to an embodiment, a turbocharger is provided which comprises the turbine according to any one of the embodiments described herein. The turbine may further have a turbine wheel 143.
An aspect relates to the use of a turbine housing clamping connection for a radial-flow turbine for countering wear on a bearing housing of the radial-flow turbine. The turbine housing clamping connection and/or the radial-flow turbine may be configured according to any of the embodiments disclosed herein. The turbine housing clamping connection has a convexly curved clamping surface region, in particular according to any one of the embodiments disclosed above.
Although specific embodiments have been illustrated and described herein, the embodiments shown may be combined or modified in a suitable manner within the scope of the present invention, without departing from the scope of protection of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21184020.2 | Jul 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/068775 | 7/6/2022 | WO |
