lathe

Abstract

This lathe comprises a rotating part, a stationary part surrounding the rotating part, and a sealing device for reducing fluid leakage through a gap between the rotating part and the stationary part. The sealing device includes: a sealing element positioned in a gap between the rotating part and the stationary part; and a first preloading element for preloading the sealing element to the outside in the radial direction of the lathe. The inner circumferential surface of the stationary part has a first groove extending along the circumferential direction of the lathe and a second groove positioned upstream of the first groove in the axial direction of the lathe, also extending along the circumferential direction. A first support part, which is able to support the sealing element, is formed on a side surface of the first groove, and a second support part, which is able to support the sealing element, is formed on a side surface of the second groove.

Description

Technical field

[0001] The present disclosure relates to a lathe.

[0002] The present application claims priority based on Japanese patent application No. 2023-170361, which was filed in Japan on September 29, 2023, and the contents of which are incorporated herein by reference. State of the art

[0003] As a sealing device for reducing fluid leakage via a gap between a rotating section and a stationary section of a lathe, such as a gas turbine and a steam turbine, in some cases a sealing device with a structure is used in which a sealing element is movable along a radial direction in accordance with an operating condition or the like of the lathe.

[0004] PTL 1 describes a sealing device comprising an arc-shaped segment having a predetermined axial dimension and carrying several sealing teeth spaced apart from one another in an axial direction and extending in a circumferential and a radial direction, and at least one series of stiff bristles extending in the circumferential direction being carried by the segment at a predetermined axial position along the segment and projecting beyond a radial dimension of the teeth, the stiff bristles being held in a first flexible carrier strip which is slidably and removably supported in a slot provided in the segment. List of citations from patent literature

[0005] [PTL 1] Japanese unexamined patent application publication no. 11-201293 Summary of the invention: Technical problem

[0006] However, if an area where a sealing element is provided is widened in the axial direction of the lathe, fluid leakage via a gap between a rotating section and a stationary section can be reduced. The sealing element, however, can be deformed by bending due to pressure received by the sealing element, and there are concerns that the sealing element may come into contact with a rotor. In this respect, PTL 1 does not disclose any knowledge on reducing the risk of contact between the rotor and the sealing element caused by bending deformation of the sealing element.

[0007] In view of the circumstances described above, an object of at least one embodiment of the present disclosure is to provide a lathe that can reduce the risk of contact between a sealing element and a rotor, while reducing fluid leakage via a gap between a rotating section and a stationary section. Solution to the problem

[0008] According to at least one embodiment of the present disclosure, a lathe comprises, in order to achieve the above task: a turning section; a stationary section surrounding the rotating section; and a sealing device for reducing fluid leakage via a gap between the rotating section and the stationary section, the sealing device includes: a sealing element provided in the gap between the rotating section and the stationary section, and a first preloading element that preloads the sealing element towards an outside in a radial direction of the lathe, are formed on an inner circumferential surface of the stationary section: a first groove extending along a circumferential direction of the lathe, and a second groove, which is positioned on an upstream side of the first groove in an axial direction of the lathe and extends along the circumferential direction, a first support section, capable of supporting the sealing element, is formed on a side surface of the first groove, and A second support section, capable of supporting the sealing element, is formed on a side surface of the second groove. Advantageous effects of the invention

[0009] According to at least one embodiment of the present disclosure, the lathe is provided which can reduce the risk of contact between the sealing element and the rotor, while reducing fluid leakage via the gap between the rotating section and the stationary section. Brief description of the drawings Fig. Figure 1 is a schematic partial sectional view of a lathe 1A according to an embodiment, which is perpendicular to an axial direction. Fig. 2A is a schematic sectional view of a sealing device 10A during start-up and shutdown procedures and during interruption of operation of the lathe 1A and is a view showing a section along line AA of Fig. 1 shows. Fig. 2B is a schematic sectional view of the sealing device 10A during a load operation of the lathe 1A and is a view showing a section along line AA of Fig. 1 shows. Fig. 3A is a schematic sectional view of the sealing device 10A during the start-up and shutdown procedures and during the interruption of operation of the lathe 1A and is a view showing a section along line BB of Fig. 1 shows. Fig. 3B is a schematic sectional view of the sealing device 10A during load operation of the lathe 1A and is a view showing a section along line BB of Fig. 1 shows. Fig. Figure 4 is a schematic partial sectional view of a lathe 1B according to a further embodiment, which is perpendicular to the axial direction. Fig. 5A is a schematic sectional view of the sealing device 10B during the start-up and shutdown processes and during the interruption of operation of the lathe 1B and is a view showing a section along line CC of Fig. 4 shows. Fig. 5B is a schematic sectional view of the sealing device 10B during load operation of the lathe 1B and is a view showing a section along line CC of Fig. 4 shows. Fig. 6A is a schematic sectional view of the sealing device 10B during the start-up and shutdown procedures and during the interruption of operation of the lathe 1B and is a view showing a section along line DD of Fig. 4 shows. Fig. 6B is a schematic sectional view of the sealing device 10B during load operation of the lathe 1B and is a view showing a section along line DD of Fig. 4 shows. Fig. Figure 7 is a view showing an example of a schematic section of the sealing device 10A during the load operation of the lathe 1A. Description of embodiments

[0010] Some embodiments of the present disclosure are described below with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of components described in the embodiments or shown in the drawings are not intended to limit the scope of protection of the present invention, but are merely illustrative examples.

[0011] For example, an expression that represents a relative or absolute arrangement, such as "in a certain direction", "along a certain direction", "parallel", "perpendicular", "center", "concentric" and "coaxial", does not only strictly represent such an arrangement, but also represents a state shifted relatively by a tolerance or by an angle or distance, insofar as the same function can be obtained.

[0012] For example, an expression that represents that objects are in the same state, such as "identical", "equal" and "homogeneous", does not strictly represent only an equal state, but also a state in which there is a tolerance or difference, insofar as the same function can be maintained.

[0013] For example, an expression that represents a shape, such as a square shape and a cylindrical shape, does not only represent a shape, such as a square shape and a cylindrical shape, in a geometrically strict sense, but also represents a shape including a non-uniform section and a chamfered section within a region where the same effect can be obtained.

[0014] However, expressions such as “comprehensive”, “provided with”, “equipped with”, “contain” or “exhibit” of a component are not exclusive expressions that exclude the presence of other components. (Configuration of lathe 1A)

[0015] Fig. Figure 1 is a schematic partial sectional view of a lathe 1A according to an embodiment, which is perpendicular to an axial direction. Fig. 2A and Fig. 2B are schematic sectional views of a sealing device 10A contained in the lathe 1A, and are views showing a section along line AA in Fig. Show 1. Fig. 3A and Fig. Figures 3B are schematic sectional views of the sealing device 10A contained in the lathe 1A, and are views showing a section along line BB in Fig. Show 1. Show here Fig. 2A and Fig. 3A Views showing the sealing device 10A during start-up and shutdown procedures and during interruption of operation of the lathe 1A. Fig. 2B and Fig. 3B are views showing the sealing device 10A during a load operation of the lathe 1A.

[0016] The lathe 1A, according to some embodiments, is a fluid machine, such as a turbine (a gas turbine, a steam turbine, or the like), a compressor, and a pump. As in Fig. As shown in Figures 1 to 3B, the lathe 1A according to the embodiment includes a rotating section 2 (rotor) and a stationary section 4 (in Fig. 1 (not shown), which is provided on an outer circumferential side of the rotating section 2 and which surrounds the rotating section 2. The rotating section 2 is supported by a bearing (not shown) so that it is rotatable about a central axis O. The stationary section 4 comprises a housing that accommodates the rotating section 2 and a stationary element that is supported by the housing. The stationary section 4 may include a blade ring for supporting a stator blade or a stationary element (for example, a dummy ring, a retaining ring, or the like) for supporting a sealing element or the like.

[0017] In the following description, unless otherwise specified, the term "axial direction" means an axial direction of the lathe 1A (a direction of the central axis O), that is, an axial direction of the rotating section 2; the term "radial direction" means a radial direction of the lathe 1A, that is, a radial direction of the rotating section 2; and the term "circumferential direction" means a circumferential direction of the lathe 1A, that is, a circumferential direction of the rotating section 2.

[0018] An annular gap g, through which a fluid flows, is formed between the rotating section 2 and the stationary section 4 in the radial direction. As in Fig. As shown in Figures 2A to 3B, the annular gap g contains a high-pressure section 6 through which a fluid at relatively high pressure flows in the axial direction on an upstream side of the sealing device 10A, and a low-pressure section 8 through which a fluid at relatively low pressure (a lower pressure than that in the high-pressure section 6) flows in the axial direction on a downstream side of the sealing device 10A. The high-pressure section 6 and the low-pressure section 8 are positioned such that they are offset from each other in the axial direction.In the following description, the upstream side in the axial direction means an upstream side of the flow of a fluid in the gap g in the axial direction, that is, a side that is closer in the axial direction to the high-pressure section 6, and the downstream side in the axial direction means a downstream side of the flow of the fluid in the gap g in the axial direction, that is, a side that is closer in the axial direction to the low-pressure section 8.

[0019] The lathe 1A according to some embodiments includes the sealing device 10A for reducing fluid leakage via the gap g between the rotating section 2 and the stationary section 4. The sealing device 10A is described in more detail below. (Configuration of sealing device 10A)

[0020] As in Fig. As shown in Figures 1 to 3B, the sealing device 10A comprises a movable sealing element 20 (sealing element) located between the rotating section 2 and the stationary section 4 in the radial direction of the lathe 1A, and a retaining element 30 (first retaining element) for movably supporting the movable sealing element 20 along the radial direction. In one embodiment, as shown in Fig. Figure 1 shows the movable sealing element 20 and the retaining element 30 along the circumferential direction. That is, the movable sealing element 20 and the retaining element 30 can have a ring shape or an arc shape (a shape in which the ring shape is subdivided in the circumferential direction).

[0021] In some embodiments, for example, as in Fig. Figure 1 shows that the sealing device 10A includes a fixed sealing element 40, which is positioned such that it is adjacent to the movable sealing element 20 in the circumferential direction. The fixed sealing element 40 is essentially configured so that it does not move along the radial direction. In the Fig. In the embodiment shown in Figure 1, the sealing device 10A includes the movable sealing elements 20, which are provided above and below the rotating section 2 in an up-down direction (vertical direction), and several fixed sealing elements 40, which are provided such that they are adjacent to an end section of the movable sealing element 20 in the circumferential direction on one side of the rotating section 2.

[0022] As in Fig. As shown in Figures 2A to 3B, the movable sealing element 20 is located between the high-pressure section 6 and the low-pressure section 8 in the axial direction of the lathe 1A. In the Fig. In the embodiment shown in Figures 2A to 3B, several sealing ribs 24 are provided on a surface 20a (inner circumferential surface) of the movable sealing element 20, which faces the rotating section 2. In some embodiments, several sealing ribs may be provided on an outer circumferential surface 2a of the rotating section 2 (i.e., a surface facing the movable sealing element 20).

[0023] The movable sealing element 20 has an outer circumferential surface 20b facing the stationary section 4, and a gap 21, which can communicate with the high-pressure section 6, is formed between the outer circumferential surface 20b and the stationary section 4 in the radial direction. That is, a pressure of a fluid from the high-pressure section 6 acts on the outer circumferential surface 20b of the movable sealing element 20.

[0024] The retaining element 30 is at least partially received in a groove 5 (first groove) provided in the stationary section 4, such that it extends along the circumferential direction. The groove 5 is designed to be recessed radially in the direction of an inner circumferential surface 4a of the stationary section 4 on an outer side and is formed by a pair of side surfaces 63 and 64 and a bottom surface 65 connecting the pair of side surfaces 63 and 64. Each of the pair of side surfaces 63 and 64 is formed along a plane perpendicular to the axial direction and is arranged to face the other in the axial direction. The groove 5 can be provided in the housing (stationary section 4) that receives the rotating section 2 of the lathe 1A or in the stationary element (stationary section 4) that is supported by the housing.The groove 5 can, for example, be provided in the turbine dummy ring (stationary section 4) of the steam turbine or in the retaining ring (stationary section 4) of the gas turbine. In a... Fig. In the exemplary embodiment shown in Figures 2A to 3B, the retaining element 30 comprises a base section 32 which is received in the groove 5 and an inner projection section 34 which projects from the base section 32 to an inside in the radial direction.

[0025] The length of a section of the retaining element 30 that is received in the groove 5 in the axial direction (a length of the base section 32 in the axial direction in the embodiment shown) is slightly shorter than the length of the groove 5 in the axial direction. Therefore, the retaining element 30 is positioned in the axial direction by the groove 5 in a state in which there is axial play between the groove 5 and the retaining element 30.

[0026] The retaining element 30 can have a contact section 36 which abuts an axial projection section 7 which extends in the axial direction into the groove 5 of the stationary section 4 in at least part of a region in the circumferential direction (for example, a section which is in Fig. 2A and Fig. (as shown in Figure 2B). The axial projection section 7 projects from the side surface 63 on the upstream side of the pair of side surfaces 63 and 64 of the groove 5 to the downstream side in the axial direction. The contact section 36 of the retaining element 30 is positioned on the outside of the axial projection section 7 in the radial direction. A preloading element 42 can be provided in the groove 5 to preload the retaining element 30 towards the inside in the radial direction, both on the outside of the retaining element 30 in the radial direction and on the inside of the stationary section 4 in the radial direction. The retaining element 30 can be positioned radially by preloading it towards the inside in the radial direction with the preloading element 42 and by the contact section 36 bearing against the axial projection section 7, thus regulating the position of the retaining element 30 in the radial direction.

[0027] In some embodiments, for example, as in Fig. 2A and Fig. Figure 2B shows the sealing device 10A comprising a head section 52, which is received in the retaining element 30, and a shaft section 54, which extends along the radial direction and connects the head section 52 and the movable sealing element 20. The movable sealing element 20 is supported by the retaining element 30 such that it is movable along the radial direction via the shaft section 54 and the head section 52, which are connected to the movable sealing element 20. The head section 52 is received inside a receiving chamber 31 provided in the retaining element 30. The shaft section 54 is designed to penetrate a hole 33 provided in the retaining element 30 to communicate with the receiving chamber 31. Fig. 2A and Fig. In the exemplary embodiment shown in Figure 2B, the sealing device 10A includes a bolt section 50, and the head section 52 and the shaft section 54, described above, are part of the bolt section 50. In some embodiments, the head section 52 and the shaft section 54 may each be configured with separate elements. The head section 52 and / or the shaft section 54 may include a pin.

[0028] Here, the axial length of the hole 33 is smaller than the diameter of the head section 52 and larger than the diameter of the shaft section 54. Furthermore, the radial length of the receiving space 31 is longer than the radial length of the head section 52. Therefore, the head section 52 and the shaft section 54 (bolt section 50) are movable along the radial direction within the receiving space 31, while the head section 52 does not extend out of the receiving space 31. The movable sealing element 20, which is connected to the shaft section 54 (bolt section 50), is movable along the radial direction together with the head section 52 and the shaft section 54 (bolt section 50). As shown in Fig. 2A and Fig. As shown in Figure 2B, the shaft section 54 can have an end section on which a screw 56 is formed and can be screwed into a screw hole 26 provided in the movable sealing element 20. In some embodiments, the shaft section 54 (for example, the pin) can be connected to the movable sealing element 20 by shrink fitting, welding, or the like.

[0029] In some embodiments, the head section 52 and the shaft section 54 (bolt section 50) described above can each be provided at several positions in the circumferential direction.

[0030] In some embodiments, the sealing device 10A may include a preloading element 60 (first preloading element) configured to preload the movable sealing element 20 along the radial direction against the retaining element 30 towards the outside in the radial direction (see Fig. 2A and Fig. 2B). As in Fig. 2A and Fig. As shown in Figure 2B, the prestressing element 60 can be positioned between a surface 53 of the head section 52, which faces the inside in the radial direction, and a surface 37 of an inner wall surface, which forms the receiving space 31 of the retaining element 30 and faces the outside in the radial direction. Fig. 2A and Fig. In the exemplary embodiment shown in 2B, the preload element 60 contains several disc springs 62.

[0031] In some embodiments, the prestressing element 60 described above can be provided at any of the several positions in the circumferential direction.

[0032] At a position where the preload element 60 is not provided, or at a position where the head section 52 and the shank section 54 (bolt section 50) are not provided in the circumferential direction, for example, as shown in Fig. 3A and Fig. As shown in Figure 3B, the movable sealing element 20 is partially received in the groove 5 of the stationary section 4. The movable sealing element 20 can have a sealing element main body section 70, the inner circumferential surface 20a of which faces the outer circumferential surface 2a of the rotating section 2 in at least a portion of its area in the circumferential direction (for example, a section that is in Fig. 3A and Fig. 3B), includes a radial projection section 72, which extends radially from the outer circumferential surface 20b of the sealing element main body section 70 to the outside, and an axial projection section 74 (shoulder section), which extends axially from a side surface 73 of the radial projection section 72 on the upstream side to the upstream side.

[0033] The main body section 70 of the sealing element has an annular or arc-shaped profile (a shape in which the annular form is subdivided in the circumferential direction) to follow the outer circumferential surface 2a of the rotating section 2. A radially outer end section of the radial projection section 72 and the axial projection section 74 are received in the groove 5. The radial projection section 72 is positioned radially between the main body section 70 of the sealing element and the base section 32 of the retaining element 30. The axial projection section 74 is positioned radially between the base section 32 of the retaining element 30 and the axial projection section 7 of the stationary section 4 and engages with (behind) the axial projection section 7 when the movable sealing element 20 is positioned radially on the inside (during the operation of the lathe 1A under load).The axial projection section 7 of the stationary section 4 acts as the first support section that supports the movable sealing element 20 by being positioned on the inside of the axial projection section 74 of the movable sealing element 20 in the radial direction and engaging with (bearing against) the axial projection section 74 and supporting the axial projection section 74 when the movable sealing element 20 is positioned on the inside in the radial direction.

[0034] As in Fig. As shown in Figures 2A to 3B, a groove 9 (second groove) is formed on the upstream side of the groove 5 in the axial direction and extends along the circumferential direction on the inner circumferential surface 4a of the stationary section 4. The groove 9 is designed to be recessed radially from the inner circumferential surface 4a of the stationary section 4 on an outer side and is formed by a pair of side surfaces 66 and 67 and a bottom surface 68 connecting the pair of side surfaces 66 and 67. The stationary section 4 includes a partition section 11 that projects radially from the inner circumferential surface 4a to the inner side to separate the groove 5 and the groove 9 from each other in the axial direction, and the partition section 11 extends along the circumferential direction. Each of the pair of side surfaces 66 and 67 is formed along the plane perpendicular to the axial direction and is arranged so that they face each other in the axial direction.An axial projection section 69, extending axially from the upstream side surface 66 to the downstream side, is formed on the groove 5 below the pair of side surfaces 66 and 67. The groove 9 can be provided in the housing (stationary section 4) that accommodates the rotating section 2 of the lathe 1A, or in the stationary element (stationary section 4) supported by the housing. The groove 9 can, for example, be provided in the turbine dummy ring (stationary section 4) of the steam turbine or in the retaining ring (stationary section 4) of the gas turbine.

[0035] Furthermore, the movable sealing element 20 contains in at least one part of the area in the circumferential direction (for example, a section that is in Fig. 2A and Fig. 2B is shown, and a section that is in Fig. 3A and Fig. 3B), a radial projection section 75, which is positioned on the upstream side of the radial projection section 72 in the axial direction and which projects from the outer circumferential surface 20b of the sealing element main body section 70 to the outside in the radial direction, and an axial projection section 77, which projects from a side surface 76 of the radial projection section 75 on the upstream side in the axial direction to the upstream side in the axial direction.

[0036] A radially outer end section of the radial projection section 75 and the axial projection section 77 are received in the groove 9. The radial projection section 75 is positioned radially between the sealing element main body section 70 and the bottom surface 68 of the groove 9, and a gap is provided between each of the side surfaces 66 and 67 of the groove 9 and the radial projection section 75. The axial projection section 77 is positioned radially between the axial projection section 69 and the bottom surface 68 of the groove 9 and engages with (behind) the axial projection section 69 when the movable sealing element 20 is positioned radially on the inside (during the load operation of the lathe 1A).The axial projection section 69 of the stationary section 4 acts as a second support section that supports the movable sealing element 20 by being positioned on the inside of the axial projection section 77 of the movable sealing element 20 in the radial direction and engaging with (bearing against) the axial projection section 77 to support the axial projection section 77.

[0037] Here, the operation of the sealing device 10A described above is briefly described. During the start-up and shutdown processes or the interruption of operation of the lathe 1A, the movable sealing element 20 is pre-tensioned radially towards the outside by the pre-tensioning element 60, and a large clearance is maintained between the rotating section 2 and the movable sealing element 20 (or the sealing rib 24) (see Fig. 2A and Fig. 3A). When the load on the lathe 1A increases, a pressure differential between the high-pressure section 6 and the low-pressure section 8 increases, and thus a difference arises between a pressure acting on the outer circumferential surface 20b of the movable sealing element 20 (a pressure of a high-pressure fluid in the high-pressure section 6) and a pressure acting on the inner circumferential surface 20a (a pressure that decreases from a high-pressure side to a low-pressure side). If a radially inward force exerted on the movable sealing element 20 due to this pressure differential overcomes a radially outward preload force of the preload element 60, the movable sealing element 20 moves to a radially inward position and a clearance between the rotating section 2 and the movable sealing element 20 (or the sealing rib 24) is reduced (see Fig. 2B and Fig. 3B). During the operation of the lathe 1A under load (during rated load operation or the like), the pressure of the high-pressure fluid of the high-pressure section 6 continues to act on the outer circumferential surface 20b of the movable sealing element 20 (more specifically, an area from an upstream end of the outer circumferential surface 20b to a sliding surface 22 to be described later), and the pressure differential described above is maintained. Therefore, the clearance between the rotating section 2 and the movable sealing element 20 (or the sealing rib 24) is maintained in such a way that it is small (see Fig. 2B and Fig. 3B) .

[0038] In some embodiments, for example, as in Fig. As shown in Figures 2A to 3B, the radial projection section 72 of the movable sealing element 20 forms the sliding surface 22, which is axially adjacent to the inner projection section 34 of the retaining element 30 and is slidable with the inner projection section 34. The inner projection section 34 has an adjacent surface 35 that faces the sliding surface 22 of the movable sealing element 20 in the axial direction. That is, the sliding surface 22 of the movable sealing element 20 and the adjacent surface 35 of the inner projection section 34 are slidable relative to each other.

[0039] In the Fig. In the embodiments shown in Figures 2A to 3B, the inner projection section 34 of the retaining element 30 is positioned axially closer to the low-pressure section 8 than the sliding surface 22 of the movable sealing element 20 (that is, the sliding surface 22 of the movable sealing element 20 is positioned closer to the high-pressure section 6 than the inner projection section 34). Therefore, because a force is exerted axially on the movable sealing element 20 from one side of the high-pressure section 6 to one side of the low-pressure section 8 due to a pressure difference between the high-pressure section 6 and the low-pressure section 8 during operation of the lathe 1A, the movable sealing element 20 and the retaining element 30 slide in a state in which the movable sealing element 20 is pressed towards the inner projection section 34 of the retaining element 30.

[0040] In the prior art sealing device, that is, the sealing device in which the movable sealing element is received in the groove of the stationary section (for example, the stationary element, such as the dummy ring and the retaining ring) of the lathe (i.e., the sealing device that does not contain the retaining element), the sealing element and the stationary section (the stationary element that has the groove that receives the sealing element) slide when the movable sealing element moves along the radial direction. If this sliding is repeated, wear or the like occurs on the sliding surfaces of the sealing element and the stationary section, and the condition (coefficient of friction or the like) of the sliding surfaces changes from an intended state.If the sliding surfaces deviate from their intended state in this way, the operation of the moving sealing element will deviate from expectations; for example, the moving sealing element may not move at the desired time, and the operation of the sealing device may become unstable. As a result, the efficiency of the lathe may decrease, or the risk of contact between the sealing element and the rotating section may increase. Although it is conceivable to maintain the sliding surface in its intended state by replacing a worn component, the worn component (for example, the dummy ring or the retaining ring) is a large component that forms part of the stationary section of the lathe, and such a large component cannot always be easily replaced due to cost or other reasons.

[0041] In this respect, in the embodiment described above, the inner projecting section 34 of the retaining element 30, which is received in the groove 5 provided in the stationary section 4, and the sliding surface 22 of the movable sealing element 20, which is supported by the retaining element 30 so that it is movable in the radial direction, are adjacent to each other in the axial direction. Therefore, when the movable sealing element 20 moves along the radial direction, the sliding surface 22 of the movable sealing element 20 and the inner projecting section 34 of the retaining element 30 slide against each other.Therefore, if a sliding section (the sliding surface 22 of the movable sealing element 20 and the inner projecting section 34 of the retaining element 30) is worn, an area of ​​the sliding section can be maintained in the intended state (for example, a state with a specified coefficient of friction) by replacing the retaining element 30 and / or the movable sealing element 20. In this way, since it is easy to maintain the area of ​​the sliding section in the intended state, it is easy to maintain a state in which the movable sealing element 20 operates stably in the lathe 1A. That is, it is easy to maintain stable operation of the sealing device 10A in the lathe 1A.

[0042] Furthermore, in the embodiment described above, the movable sealing element 20 is pre-tensioned radially towards the outside by the pre-tensioning element 60 against the retaining element 30, which is received in the groove 5 of the stationary section 4. In this way, since the movable sealing element 20 is subjected to a radially outward force by the pre-tensioning element 60, the movable sealing element 20 can move freely along the radial direction in accordance with an operating condition of the lathe 1A.

[0043] Furthermore, in the embodiment described above, the movable sealing element 20 is supported by the retaining element 30 such that it is movable in the radial direction via the head section 52 and the shaft section 54 (bolt section) 50, and a radially outward force is exerted on the movable sealing element 20 via the head section 52 and the shaft section 54 (bolt section) 50 by the preload element 60, which is provided between the head section 52 and the inner wall surface (surface 37) of the retaining element 30. In this way, a radially outward preload force can be exerted on the movable sealing element 20, while the movable sealing element 20 is supported so that it is movable along the radial direction, with a simple configuration using the head section 52 and the shaft section 54 (bolt section) 50.

[0044] Furthermore, in the prior art sealing device (i.e., the sealing device that does not include the retaining element), the preloading element for preloading the movable sealing element radially towards the outside is provided between the movable sealing element and the stationary element. For this reason, when the sealing device is installed in the lathe, the insertion of the movable sealing element into the groove along the circumferential direction can be hindered by a preload (a force along the radial direction) exerted on the preloading element.

[0045] In this respect, in the embodiment described above, the movable sealing element 20 is supported by the retaining element 30, and the preloading element 60 for preloading the movable sealing element 20 towards the outside in the radial direction is received in the retaining element 30. Therefore, when the movable sealing element 20 and the preloading element 60 are assembled with the retaining element 30, the sealing device 10A, which contains the movable sealing element 20, can be installed in the lathe 1A by inserting the retaining element 30 circumferentially into the groove 5 of the stationary section 4. Thus, even in a state where a relatively large preload is applied to the preloading element 60, the preload does not impede the insertion of the sealing device 10A into the groove, and the sealing device 10A can be easily installed in the lathe 1A.

[0046] Furthermore, in the embodiment described above, the groove 5, which extends along the circumferential direction of the lathe 1A, and the groove 9, which is positioned on the upstream side of the groove 5 in the axial direction and extends along the circumferential direction, are formed on the inner circumferential surface 4a of the stationary section 4, the axial projection section 7 (first support section), which can support the movable sealing element 20, is formed on the side surface 63 of the groove 5, and the axial projection section 69 (second support section), which can support the movable sealing element 20, is formed on the side surface 66 of the groove 9.For this reason, for example, in comparison to a case where the groove 9 is not provided in the stationary section 4 and the movable sealing element 20 is only supported by the axial projection section 7, the movable sealing element 20 can be supported by the axial projection section 7 and the axial projection section 69 at different positions in the axial direction. Therefore, bending deformation (for example, deformation in which an upstream end section of the movable sealing element 20 bends towards the inside in the radial direction, as indicated by an arrow F in ) can be prevented. Fig. (2B specified) of the movable sealing element 20 can be suppressed. Furthermore, the number of components can be reduced compared to a case where the sealing elements are individually provided in groove 5 and groove 9, for example. Therefore, the risk of contact between the movable sealing element 20 and the rotating section 2 can be reduced by suppressing the bending deformation of the movable sealing element 20, while fluid leakage via the gap g between the rotating section 2 and the stationary section 4 is reduced with a small number of components. (Modification example)

[0047] Fig. Figure 4 is a schematic partial sectional view of a lathe 1B according to a further embodiment, which is perpendicular to the axial direction. Fig. 5A and Fig. Figures 5B are schematic sectional views of a sealing device 10B contained in the lathe 1B, and are views showing a section along line CC of Fig. Show 4. Fig. 6A and Fig. Figures 6B are schematic sectional views of the sealing device 10B contained in the lathe 1B, and are views showing a section along line DD of Fig. Show 4. Show here Fig. 5A and Fig. 6A Views showing the sealing device 10B during the start-up and shutdown procedures and during the interruption of operation of the lathe 1B. Fig. 5B and Fig. Figures 6B are views showing the sealing device 10B during the operation of the lathe 1B under load.

[0048] At the in Fig. In Figures 4 to 6B, reference numerals are given for the lathe 1B shown, which are common to the respective configurations of the lathe 1A described above. Unless otherwise stated, the same configurations as the respective configurations of lathe 1A are indicated, and any further description is omitted. In the case of lathe 1B, the configuration of the sealing device 10B differs from the configuration of the sealing device 10A described above. In particular, as shown in Fig. Figures 5A to 6B show the sealing device 10B being distinguished from the sealing device 10A by the fact that the sealing device 10B includes a retaining element 80 and a preloading element 94 which are received in the groove 9.

[0049] In the following description, unless otherwise specified, the term "axial direction" means an axial direction of the lathe 1B (the direction of the central axis O), that is, the axial direction of the rotating section 2; the term "radial direction" means a radial direction of the lathe 1B, that is, the radial direction of the rotating section 2; and the term "circumferential direction" means a circumferential direction of the lathe 1B, that is, the circumferential direction of the rotating section 2.

[0050] The retaining element 80 is at least partially received in the groove 9 (second groove), which is provided in the stationary section 4 such that it extends along the circumferential direction. The groove 9 is designed such that it is recessed in the radial direction from the inner circumferential surface 4a of the stationary section 4 on the outside and is formed by the pair of side surfaces 66 and 67 and the bottom surface 68, which connects the pair of side surfaces 66 and 67. Each of the pair of side surfaces 66 and 67 is formed along the plane perpendicular to the axial direction and is arranged such that they face each other in the axial direction. In the Fig. In the exemplary embodiment shown in Figures 2A to 3B, the retaining element 80 comprises a base section 82 which is received in the groove 9 and an inner projection section 83 which projects from the base section 82 to the inside in the radial direction.

[0051] The length of a section of the retaining element 80 that is received in the groove 9 in the axial direction (a length of the base section 82 in the axial direction in the embodiment shown) is slightly shorter than the length of the groove 9 in the axial direction. Therefore, the retaining element 80 is positioned in the axial direction by the groove 9 in a state in which there is axial play between the groove 9 and the retaining element 80.

[0052] The retaining element 80 can have a contact section 85 which abuts the axial projection section 69, which extends in the axial direction into the groove 9 of the stationary section 4 in at least part of a region in the circumferential direction (for example, a section which is in Fig. 5A and Fig. (as shown in Figure 5B). The axial projection section 69 projects from the side surface 66 on the upstream side of the pair of side surfaces 66 and 67 of the groove 9 to the downstream side in the axial direction. The contact section 85 of the retaining element 80 is positioned on the outside of the axial projection section 69 in the radial direction. A preloading element 86 can be provided in the groove 9 to preload the retaining element 80 towards the inside in the radial direction, both on the outside of the retaining element 80 in the radial direction and on the inside of the stationary section 4 in the radial direction. The retaining element 80 can be positioned in the radial direction by preloading the retaining element 80 towards the inside in the radial direction with the preloading element 86 and by bearing the contact section 85 against the axial projection section 69, in order to regulate the position of the retaining element 80 in the radial direction.

[0053] In some embodiments, for example, as in Fig. 5A and Fig. Figure 5B shows the sealing device 10B comprising a head section 87, which is received in the retaining element 80, and a shaft section 88, which extends along the radial direction and connects the head section 87 and the movable sealing element 20. The movable sealing element 20 is supported by the retaining element 80 such that it is movable along the radial direction via the shaft section 88 and the head section 87, which are connected to the movable sealing element 20. The head section 87 is received inside a receiving chamber 89 provided in the retaining element 80. The shaft section 88 is designed to penetrate a hole 90 provided in the retaining element 80 to communicate with the receiving chamber 89. Fig. 5A and Fig. In the exemplary embodiment shown in Figure 5B, the sealing device 10B includes a bolt section 91, and the head section 87 and the shaft section 88, described above, are part of the bolt section 91. In some embodiments, the head section 87 and the shaft section 88 may each be configured with separate elements. The head section 87 and / or the shaft section 88 may include a pin.

[0054] Here, the axial length of the hole 90 is smaller than the diameter of the head section 87 and larger than the diameter of the shaft section 88. Furthermore, the radial length of the receiving space 89 is longer than the radial length of the head section 87. Therefore, the head section 87 and the shaft section 88 (bolt section 91) are movable along the radial direction within the receiving space 89, while the head section 87 does not extend out of the receiving space 89. The movable sealing element 20, which is connected to the shaft section 88 (bolt section 91), is movable along the radial direction together with the head section 87 and the shaft section 88 (bolt section 91). As in Fig. 5A and Fig. As shown in Figure 5B, the shaft section 88 can have an end section on which a screw 92 is formed and can be screwed into a screw hole 93 provided in the movable sealing element 20. In some embodiments, the shaft section 88 (for example, the pin) can be connected to the movable sealing element 20 by shrink fitting, welding, or the like.

[0055] In some embodiments, the head section 87 and the shaft section 88 (bolt section 91) described above can each be provided at several positions in the circumferential direction.

[0056] In some embodiments, the sealing device 10B can include the preloading element 94 (second preloading element) which is configured to preload the movable sealing element 20 along the radial direction against the retaining element 80 towards the outside in the radial direction (see Fig. 5A and Fig. 5B). As in Fig. 5A and Fig. As shown in Figure 5B, the prestressing element 94 can be positioned between a surface 95 of the head section 87, which faces the inside in the radial direction, and a surface 96 of an inner wall surface, which forms the receiving space 89 of the retaining element 80 and faces the outside in the radial direction. In the Fig. 5A and Fig. In the exemplary embodiment shown in 5B, the preload element 94 contains several disc springs 97.

[0057] In some embodiments, the prestressing element 94 described above can be provided at any of the several positions in the circumferential direction.

[0058] At a position where the preload element 94 is not provided, or at a position where the head section 87 and the shank section 88 (bolt section 91) are not provided in the circumferential direction, for example, as shown in Fig. 6A and Fig. As shown in Figure 6B, the movable sealing element 20 is partially received in the groove 9 of the stationary section 4.

[0059] Furthermore, in the sealing device 10B, the movable sealing element 20 contains in at least one part of the area in the circumferential direction (for example, a section which is in Fig. 6A and Fig. 6B is shown) the radial projection section 75, which is positioned on the upstream side of the radial projection section 72 in the axial direction and which projects from the outer circumferential surface 20b of the sealing element main body section 70 to the outside in the radial direction, and the axial projection section 77, which projects from the side surface 76 of the radial projection section 75 on the upstream side in the axial direction to the upstream side in the axial direction.

[0060] A radially outer end section of the radial projection section 75 and the axial projection section 77 are received in the groove 9. The radial projection section 75 is positioned radially between the sealing element main body section 70 and the bottom surface 68 of the groove 9, and the gap is provided between each of the side surfaces 66 and 67 of the groove 9 and the radial projection section 75. The axial projection section 77 is positioned radially between the axial projection section 69 and the bottom surface 68 of the groove 9 and engages with (behind) the axial projection section 69 when the movable sealing element 20 is positioned radially on the inside (during the load operation of the lathe 1A).The axial projection section 69 of the stationary section 4 acts as the second support section, supporting the movable sealing element 20 by being positioned on the inside of the axial projection section 77 of the movable sealing element 20 in the radial direction and engaging with the axial projection section 77 to support the axial projection section 77.

[0061] Here, the operation of the sealing device 10B described above is briefly described. During the start-up and shutdown processes or the interruption of operation of the lathe 1B, the movable sealing element 20 is pre-tensioned radially towards the outside by the pre-tensioning element 60 and the pre-tensioning element 94, and a large clearance is maintained between the rotating section 2 and the movable sealing element 20 (or the sealing rib 24) (see Fig. 5A and Fig. 6A). When the load on the lathe 1B increases, a pressure differential between the high-pressure section 6 and the low-pressure section 8 increases, and thus a difference arises between a pressure acting on the outer circumferential surface 20b of the movable sealing element 20 (a pressure of a high-pressure fluid in the high-pressure section 6) and a pressure acting on the inner circumferential surface 20a (a pressure that decreases from the high-pressure side to the low-pressure side). When a radially inward force exerted on the movable sealing element 20 due to this pressure differential overcomes a radially outward preload force of the preload element 60 and the preload element 94, the movable sealing element 20 moves to a radially inward position and a clearance between the rotating section 2 and the movable sealing element 20 (or the sealing rib 24) is reduced (see Fig. 5B and Fig. 6B). During the operation of the lathe 1B under load (during rated load operation or the like), the pressure of the high-pressure fluid of the high-pressure section 6 continues to act on the outer circumferential surface 20b of the movable sealing element 20 (particularly extending to an area from the upstream end of the outer circumferential surface 20b to the sliding surface 22), and the pressure differential described above is maintained. Therefore, the clearance between the rotating section 2 and the movable sealing element 20 (or the sealing rib 24) is maintained in such a way that it is small (see Fig. 5B and Fig. 6B).

[0062] In some embodiments, for example, as in Fig. Figures 5A to 6B show the radial projection section 75 of the movable sealing element 20 arranged in the axial direction such that it faces the inner projection section 83 of the retaining element 80. A gap in the axial direction is provided between the radial projection section 75 and the inner projection section 83 in at least a portion of a region in the circumferential direction. That is, a side surface 98 of the radial projection section 75 on the downstream side in the axial direction and a side surface 99 of the inner projection section 83 on the upstream side in the axial direction face each other in the axial direction, and a gap in the axial direction is provided between the side surface 98 and the side surface 99 in at least a portion of the region in the circumferential direction.For this reason, a fluid in the high-pressure section 6 is supplied to the gap between the sealing element 20 and the stationary section 4 and to a gap between the sealing element 20 and the retaining element 30 on one side of groove 5 through a gap between the radial projection section 75 and the inner projection section 83, so that the pressure of the fluid in the high-pressure section 6 acts on an area from the upstream end of the outer circumferential surface 20b of the sealing element 20 to the sliding surface 22 and the movable sealing element 20 can be moved in the radial direction as described above.

[0063] At the in Fig. In the embodiment shown in Figures 4 to 6B, since a radially outward force is exerted on the sealing element 20 by the preloading element 60 and the preloading element 94, the radially outward force acting on the sealing element 20 is greater compared to a case in which the preloading element 94 is not provided (see Figures 4 to 6B). Fig. 2A to 3B). For this reason, the sealing device 10B can be suitablely applied to a section in which a differential pressure increases between the upstream and downstream sides of the sealing element 20 in the gap between the stationary section 4 and the rotating section 2.

[0064] The present disclosure is not limited to the embodiments described above and also includes shapes obtained by adding modifications to the embodiments described above, or shapes obtained by appropriately combining the shapes.

[0065] For example, as in Fig. As shown in Figure 7, the partition section 11, which separates the groove 5 and the groove 9, may not be provided in the stationary section 4 of the lathe 1A or lathe 1B described above in a portion of the area in the circumferential direction. That is, the groove 5 and the groove 9 may be axially connected to each other in a portion of the area in the circumferential direction.

[0066] For example, the contents described for each of the embodiments are understood as follows.

[0067] (1) A lathe (for example, the lathes 1A and 1B described above) according to at least one embodiment of the present disclosure comprises: a rotating section (for example, the rotating section 2 described above); a stationary section (for example, the stationary section 4 described above) that surrounds the rotating section; and a sealing device (for example, the sealing devices 10A and 10B described above) for reducing fluid leakage via a gap between the rotating section and the stationary section, the sealing device includes: a sealing element (for example, the movable sealing element 20 described above) which is provided in the gap between the rotating section and the stationary section, and a first preloading element (for example, the preloading element 60 described above) that preloads the sealing element towards an outside in a radial direction of the lathe, are formed on an inner circumferential surface (for example, the inner circumferential surface 4a described above) of the stationary section: a first groove (for example, the groove 5 described above) that extends along a circumferential direction of the lathe, and a second groove (for example, the groove 9 described above) which is positioned on an upstream side of the first groove in an axial direction of the lathe and extends along the circumferential direction, a first support section (for example, the axial projection section 7 described above), which is capable of supporting the sealing element, is formed on a side surface of the first groove, and a second support section (for example, the axial projection section 69 described above), which is able to support the sealing element, is formed on a side surface of the second groove.

[0068] According to the lathe described in (1), the groove extending along the circumferential direction of the lathe and the groove positioned on the upstream side of the groove in the axial direction of the lathe, extending along the circumferential direction, are formed on the inner circumferential surface of the stationary section. The first support section capable of supporting the sealing element is formed on the side surface of the first groove, and the second support section capable of supporting the sealing element is formed on the side surface of the second groove. Therefore, for example, in contrast to a case where the second groove is not provided in the stationary section and the sealing element is supported only by the first support section, the first and second support sections can support the sealing element at positions that differ from each other in the axial direction.Therefore, bending deformation of the sealing element can be suppressed. Furthermore, the number of components can be reduced compared to a case where the sealing elements are individually provided in the first and second grooves, for example. Thus, the risk of contact between the moving sealing element and the rotating section can be reduced by suppressing bending deformation of the sealing element, while fluid leakage via the gap between the rotating and stationary sections is reduced with a smaller number of components.

[0069] (2) According to some embodiments of the lathe described in (1) The first support section extends from a side surface of the first groove on the upstream side in the axial direction to a downstream side in the axial direction, and The second support section projects from a side surface of the second groove on the upstream side in the axial direction towards the downstream side.

[0070] According to the lathe described in (2), a first support section, projecting axially from the side face of the first groove on the upstream side to the downstream side, and a second support section, projecting axially from the side face of the second groove on the upstream side to the downstream side, are provided. The first and second support sections can support the sealing element at positions that differ axially. Therefore, bending deformation of the sealing element can be suppressed. Thus, the risk of contact between the moving sealing element and the rotating section can be reduced by suppressing bending deformation of the sealing element, while fluid leakage via the gap between the rotating section and the stationary section is reduced with a small number of components.

[0071] (3) According to some embodiments of the lathe described in (1) or (2) The sealing element contains a sealing element main body section (for example, the sealing element main body section 70 described above) which is provided along the circumferential direction such that it faces an outer circumferential surface of the rotating section, a first radial projection section (for example, the radial projection section 72 described above) which projects from an outer circumferential surface of the sealing element main body section to the outside in the radial direction, a first axial projection section (for example, the axial projection section 74 described above) which projects from a side surface of the first radial projection section on the upstream side in the axial direction towards the upstream side in the axial direction, a second radial projection section (for example, the radial projection section 75 described above) which is positioned on an upstream side of the first radial projection section in the axial direction and which projects radially from the outer circumferential surface of the sealing element main body section to the outside, and a second axial projection section (for example, the axial projection section 77 described above) which projects from a side surface of the second radial projection section on the upstream side in the axial direction towards the upstream side in the axial direction, the first support section is positioned on an inside of the first axial projection section in the radial direction, and The second support section is positioned on an inner side of the second axial projection section in the radial direction.

[0072] According to the lathe described in (3), the first axial projection section can be supported by the first support section, which projects axially from the side face of the first groove on the upstream side to the downstream side, and the second axial projection section can be supported by the second support section, which projects axially from the side face of the second groove on the upstream side to the downstream side. Therefore, bending deformation of the sealing element can be suppressed. Thus, the risk of contact between the moving sealing element and the rotating section can be reduced by suppressing bending deformation of the sealing element, while fluid leakage via the gap between the rotating section and the stationary section is reduced with a small number of components.

[0073] (4) According to some embodiments of the lathe described in (3) The sealing device includes a first retaining element (for example, the retaining element 30 described above) to support the sealing element so that it is movable along the radial direction, the first retaining element indicates: a base section (for example, the base section 32 described above) which is inserted in the first groove, and an inner projection section (for example, the inner projection section 34 described above) that projects from the base section towards an inner side in the radial direction, and the first radial projection section has a sliding surface (for example, the sliding surface 22 described above) which is adjacent to the inner projection section in the axial direction and which is slidable with the inner projection section.

[0074] According to the lathe described in (4), the inner projection section of the first retaining element, which is received in the first groove provided in the stationary section, and the sliding surface of the sealing element, which is supported by the first retaining element so that it is movable in the radial direction, are adjacent to each other in the axial direction. Therefore, when the sealing element moves along the radial direction, the sliding surface of the sealing element and the inner projection section of the first retaining element slide against each other. For this reason, if the sliding section (the sliding surface of the sealing element and the inner projection section of the first retaining element) is worn, the area of ​​the sliding section can be maintained in the intended condition by replacing the first retaining element and / or the sealing element.In this way, since it is easy to maintain the surface of the sliding section in the intended state, it is easy to maintain a state in which the sealing element operates stably in the lathe. That is, it is easy to maintain stable operation of the sealing device in the lathe.

[0075] (5) According to some embodiments of the lathe described in (4), the first preloading element is received in the first holding element and is configured to preload the sealing element towards the outside in the radial direction.

[0076] According to the lathe described in (5), a radially outward force is exerted by the first preloading element on the sealing element, and the sealing element can move freely along the radial direction in accordance with an operating condition of the lathe.

[0077] (6) According to some embodiments of the lathe described in (5) The sealing device contains a second retaining element (for example, the retaining element 80 described above), which is at least partially received in the second groove and which serves to support the sealing element so that it is movable along the radial direction, and a second preloading element (for example, the preloading element 94 described above) which is received in the second retaining element and which is configured to preload the sealing element towards the outside in the radial direction, the second retaining element indicates: a base section (for example, the base section 82 described above) which is inserted in the second groove, and an inner projection section (for example, the inner projection section 83 described above) that projects from the base section to the inside in the radial direction, and A gap is provided between the second radial projection section and the inner projection section of the second retaining element in at least part of a region in the circumferential direction.

[0078] According to the lathe described in (6), since a radially outward force is exerted on the sealing element by the first preloading element and the second preloading element, the radially outward force acting on the sealing element can be increased compared to a case where the second preloading element is not provided. For this reason, the sealing device can be applied to a section where a differential pressure between the upstream and downstream sides of the sealing element increases in the gap between the stationary section and the rotating section during operation of the lathe (for example, during the lathe's rated operation or the like). Reference symbol list 1A, 1B Lathe 2 Turning section 2a, 20b External perimeter area 4 stationary section 4a, 20a Inner circumferential area 5, 9 Nut 6 High-pressure section 7, 69, 74, 77 axial projection section 8 Low-pressure section 10, 10A, 10B Sealing device 20 movable sealing element 37, 53, 95, 96 area 20a Inner perimeter area 21, g gap 22 Sliding surface 24 sealing ribs 26, 93 screw hole 30, 80 retaining element 31, 89 Recording Room 32, 82 Base section 33, 90 holes 34, 83 inner lead section 35 facing area 36, 85 Plant section 40 fixed sealing element 42, 60, 86, 94 Preload element 50, 91 bolt section 52, 87 Head section 54, 88 shaft section 56, 92 screw 62, 97 Belleville washers 63, 64, 66, 67, 73, 76, 98, 99 side surface 65, 68 floor area 70 Sealing element main body section 72, 75 radial projection section F arrow O Central axis QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2023-170361

[0002] JP 11-201293

[0005]

Claims

A lathe comprising: a rotating section; a stationary section surrounding the rotating section; and a sealing device for reducing fluid leakage via a gap between the rotating section and the stationary section, wherein the sealing device comprises: a sealing element provided in the gap between the rotating section and the stationary section, and a first preloading element that preloads the sealing element towards an outside in a radial direction of the lathe, formed on an inner circumferential surface of the stationary section: a first groove extending along a circumferential direction of the lathe, and a second groove positioned on an upstream side of the first groove in an axial direction of the lathe and extending along the circumferential direction, and a first support section capable of supporting the sealing element, formed on a side surface of the first groove.and a second support section, capable of supporting the sealing element, is formed on a side surface of the second groove. Lathe according to claim 1, wherein the first support section projects from a side surface of the first groove on the upstream side in the axial direction to a downstream side in the axial direction, and the second support section projects from a side surface of the second groove on the upstream side in the axial direction to the downstream side in the axial direction. Lathe according to claim 2, wherein the sealing element comprises: a sealing element main body section which is provided along the circumferential direction such that it faces an outer circumferential surface of the rotating section, a first radial projection section which projects radially from an outer circumferential surface of the sealing element main body section to the outside, a first axial projection section which projects axially from a side face of the first radial projection section on the upstream side to the upstream side, a second radial projection section which is positioned on an upstream side of the first radial projection section in the axial direction and which projects radially from the outer circumferential surface of the sealing element main body section to the outside, and a second axial projection section.the first support section is positioned on an inside of the first axial projection section in the radial direction, and the second support section is positioned on an inside of the second axial projection section in the radial direction. Lathe according to claim 3, wherein the sealing device comprises a first retaining element for supporting the sealing element so that it is movable along the radial direction, the first retaining element having: a base section which is received in the first groove, and an inner projection section which projects from the base section to an inner side in the radial direction, and the first radial projection section having a sliding surface which is adjacent in the axial direction to the inner projection section and which is slidable with the inner projection section. Lathe according to claim 4, wherein the first preloading element is received in the first retaining element and is configured such that it preloads the sealing element towards the outside in the radial direction. Lathe according to claim 5, wherein the sealing device comprises: a second retaining element which is at least partially received in the second groove and which serves to support the sealing element so that it is movable along the radial direction, and a second preloading element which is received in the second retaining element and which is configured to preload the sealing element towards the outside in the radial direction, the second retaining element comprising: a base section which is received in the second groove, and an inner projection section which projects from the base section towards the inside in the radial direction, and a gap is provided between the second radial projection section and the inner projection section of the second retaining element in at least a part of a region in the circumferential direction.

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