Anti-loosening fastening connecting pair capable of being used for steam turbine air cylinder
By designing an anti-loosening fastening connection pair in the turbine cylinder, and using the coordination of the limit sleeve and limit cap, the problem of loosening of the stud and nut during the heating and expansion process of the cylinder is solved, ensuring that the initial preload force is in the early stage of heating and expansion. It is not easy to loosen, improving the stability and safety of fastening.
Patent Information
- Application Number
- CN202421272797.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-05
- Publication Date
- 2025-01-17
- Estimated Expiration
- 2034-06-05
AI Technical Summary
During the heating and expansion process of the turbine cylinder, insufficient initial preload force causes loosening of the stud and nut, and excessive initial preload force may easily cause the stud to break, posing a safety hazard.
An anti-loose fastening connection pair is designed, including the main stud, main nut, limit sleeve and limit cap. The locking teeth of the limit sleeve are matched with the slot of the main nut, and the secondary studs of the limit cap are The threaded holes of the main stud are combined with the elastic buffer gasket to buffer the heating and expansion to ensure that the initial preload force is not easy to loosen in the early stages of heating and expansion.
Even if the initial preloading force is small, the vibration of the cylinder operation is not likely to cause looseness under the cooperation of the limit sleeve and the limit cap, avoiding the risk of loosening of the stud and nut after heating and expansion, and ensuring the stability of the tightening fit.
Smart Images
Figure CN222363265U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the field of fasteners, and in particular relates to an anti-loosening fastening connection pair which can be used for a steam turbine cylinder. Background Art
[0002] A steam turbine, also known as a steam turbine engine, is a rotary steam power device. It is the main equipment of modern thermal power plants and is also widely used in metallurgical industry, chemical industry, and ship power devices. The cylinder of a steam turbine is the outer shell of the turbine. Its function is to separate the flow part of the turbine from the atmosphere to form a closed steam chamber to ensure that the steam completes the energy conversion process inside the turbine. The cylinder usually includes an upper cylinder and a lower cylinder, which are fastened together by studs and corresponding nuts.
[0003] Due to the high operating temperature of the turbine cylinder, a lower pre-tightening force is usually used during the installation of the studs and nuts. In this way, metal expansion will occur during the heating process of the cylinder, studs and nuts, causing the pre-tightening force to gradually increase. If a larger pre-tightening force is used at the beginning, it is easy to cause stud breakage accidents during the heating and expansion process; but too small an initial pre-tightening force may also cause the nuts to loosen due to the vibration of the cylinder when the studs and nuts are not in place during the early stage of heating and expansion, so that the final pre-tightening force fails to meet the standard and there is a safety hazard. Therefore, a new anti-loosening fastening connection form of stud nuts is urgently needed, which can prevent the nuts from loosening due to vibration even when they have a smaller pre-tightening force. Utility Model Content
[0004] Based on the content in the background technology, the utility model provides an anti-loosening fastening connection pair that can be used for a steam turbine cylinder, including a main stud, a main nut, a limiting sleeve and a limiting cap;
[0005] The side surface of one end of the main stud is provided with a first external thread, and the side surface of the other end is provided with a second external thread, the main nut can be screwed on the second external thread of the main stud, and one end surface of the main nut is provided with at least one slot, and one end surface of the limiting sleeve is fixedly connected with at least one latching tooth, and the latching tooth is integrally connected with the limiting sleeve, and the latching tooth corresponds to the slot of the main nut one by one, and when the limiting sleeve is sleeved on the second external thread of the main stud, the latching tooth of the limiting sleeve can fall into the slot of the main nut;
[0006] The main stud is provided with a threaded hole at the end face close to the second external thread, and a secondary stud is fixedly connected to the center of the inner side of the limiting cap. The secondary stud and the threaded hole of the main stud cooperate with each other in the form of threads. When the limiting cap is sleeved on the corresponding end of the main stud, the secondary stud of the limiting cap can be screwed into the threaded hole of the main stud, and the lower end face of the limiting cap can conflict with the upper end face of the limiting sleeve.
[0007] The working principle of the above-mentioned anti-loosening fastening connection pair is as follows:
[0008] When connecting the cylinder of the steam turbine, one end of the main stud is first screwed into the screw hole of the connecting surface of the lower cylinder through the first external thread. After the other end of the main stud passes through the flange hole of the upper cylinder, the main nut is first screwed on the second external thread of the main stud, pre-tightened to the specified torque, and then the upper limit sleeve is put on so that the teeth of the limit sleeve fall into the grooves of the main nut, and the elastic buffer gasket is put on. Finally, the upper limit cap is installed, and the auxiliary stud of the limit cap is screwed into the threaded hole of the main stud. The lower end face of the limit cap conflicts with the upper end face of the limit sleeve, and the auxiliary screw of the limit cap The column can be screwed in with a standard pre-tightening force. Even if the auxiliary stud breaks in the later stage of temperature rise and expansion, it will not affect the tight fit of the main stud and the main nut. In this way, when the main nut is loosened outward due to vibration, its rotational torque will be transmitted to the limit sleeve, and the limit sleeve will be resisted by the limit cap and cannot be detached from the main stud. The auxiliary stud of the limit cap is not easy to loosen because it adopts the standard pre-tightening force. In this way, even if the initial pre-tightening force of the main nut is small, it is not easy to loosen due to vibration under the restriction of the limit sleeve and the limit cap and in the early stage of temperature rise and expansion.
[0009] Preferably, the internal thread of the main stud threaded hole and its second external thread have opposite thread directions, so that the secondary stud and the main nut of the limiting cap can be rotated in opposite directions. When the main nut is loosened outward due to vibration and the limiting cap is squeezed by the limiting sleeve, the secondary stud of the limiting cap can be screwed in more tightly.
[0010] Furthermore, the anti-loosening and fastening connection pair that can be used for the turbine cylinder also includes an elastic buffer gasket, which is arranged between the limit sleeve and the limit cap. In addition to being able to play the role of a conventional gasket, the elastic buffer gasket can also buffer the temperature by deformation, leaving a margin for the temperature increase expansion of the limit sleeve and the limit cap, thereby avoiding excessive squeezing force between them.
[0011] Through the above technical solution, the utility model at least includes the following beneficial effects:
[0012] The anti-loosening fastening connection pair that can be used for the turbine cylinder described in the present application is designed through the coordination of structures such as the main nut, the limit sleeve and the limit cap. Even if the initial pre-tightening force of the main nut is small, it is not easy to loosen due to the vibration of the cylinder operation in the early stage of temperature rise and expansion under the restriction of the limit sleeve and the limit cap. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 It is an overall schematic diagram of an anti-loosening fastening connection pair that can be used for a steam turbine cylinder as described in an embodiment of the present application;
[0014] Figure 2 It is an exploded view of the anti-loosening fastening connection pair that can be used for a steam turbine cylinder described in an embodiment of the present application. DETAILED DESCRIPTION
[0015] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. These drawings are simplified schematic diagrams that only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the structures related to the present invention.
[0016] In the description of this application, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship are only used for exemplary description and cannot be understood as limiting this patent; if there are terms such as "first", "second", etc., they are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the said features. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to the specific circumstances.
[0017] In the description of the utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the utility model can be understood according to specific circumstances.
[0018] refer to Figure 1 and Figure 2 A loose-proof fastening connection pair that can be used for a steam turbine cylinder, comprising a main stud 1, a main nut 2, a limiting sleeve 3 and a limiting cap 4;
[0019] The side surface of one end of the main stud 1 is provided with a first external thread 101, and the side surface of the other end is provided with a second external thread 102. The main nut 2 can be screwed on the second external thread 102 of the main stud 1. The upper end surface of the main nut 2 is provided with at least one slot 201. In this embodiment, four slots 201 are evenly distributed on its end surface. The lower end surface of the limiting sleeve 3 is fixedly connected with at least one latch tooth 301. In this embodiment, four latch teeth 301 are evenly distributed on its end surface. Specifically, the latch teeth 301 are integrally connected with the limiting sleeve 3. The latch teeth 301 correspond to the slots 201 of the main nut 2 one by one. When the limiting sleeve 3 is sleeved on the second external thread 102 of the main stud 1, the latch teeth 301 of the limiting sleeve 3 can fall into the slots 201 of the main nut 2.
[0020] The main stud 1 is provided with a threaded hole 103 at the end face close to the second external thread 102, and a secondary stud 401 is fixedly connected at the center of the inner side of the limiting cap 4. The secondary stud 401 and the threaded hole 103 of the main stud 1 are matched with each other in the form of threads. When the limiting cap 4 is sleeved on the corresponding end of the main stud 1, the secondary stud 401 of the limiting cap 4 can be screwed into the threaded hole 103 of the main stud 1, and the lower end face of the limiting cap 4 can conflict with the upper end face of the limiting sleeve 3.
[0021] The working principle of the above-mentioned anti-loosening fastening connection pair is as follows:
[0022] When connecting the cylinder of the steam turbine, one end of the main stud 1 is first screwed into the screw hole of the connecting surface of the lower cylinder through the first external thread 101. After the other end of the main stud 1 passes through the flange hole of the upper cylinder, the main nut 2 is first screwed onto the second external thread 102 of the main stud 1, pre-tightened to a specified torque, and then the upper limit sleeve 3 is put on, so that the tooth 301 of the limit sleeve 3 falls into the groove 201 of the main nut 2, and finally the upper limit cap 4 is installed, and the auxiliary stud 401 of the limit cap 4 is screwed into the threaded hole 103 of the main stud 1, so that the lower end surface of the limit cap 4 and the upper end surface of the limit sleeve 3 conflict with each other, and the limit cap 4 The auxiliary stud 401 can be screwed in with a standard pre-tightening force. Even if the auxiliary stud 401 breaks in the later stage of temperature rise and expansion, it will not affect the tight fit of the main stud 1 and the main nut 2. In this way, when the main nut 2 is loosened outward due to vibration, its rotational torque will be transmitted to the limiting sleeve 3, and the limiting sleeve 3 is resisted by the limiting cap 4 and cannot be detached from the main stud 1. The auxiliary stud 401 of the limiting cap 4 is not easy to loosen because it adopts the standard pre-tightening force. In this way, even if the initial pre-tightening force of the main nut 2 is small, it is not easy to loosen due to vibration under the restriction of the limiting sleeve 3 and the limiting cap 4 and in the early stage of temperature rise and expansion.
[0023] In a preferred embodiment, the internal thread of the threaded hole 103 of the main stud 1 and its second external thread 102 have opposite thread directions, so that the secondary stud 401 of the limiting cap 4 and the main nut 2 can have opposite rotation directions. When the main nut 2 is loosened outward due to vibration and the limiting cap 4 is squeezed by the limiting sleeve 3, the secondary stud 401 of the limiting cap 4 can be screwed in more tightly.
[0024] In a further embodiment, the anti-loosening and fastening connection pair that can be used for the turbine cylinder also includes an elastic buffer gasket 5, which is arranged between the limit sleeve 3 and the limit cap 4. In addition to being able to play the role of a conventional gasket, the elastic buffer gasket 5 can also buffer the deformation and reserve a margin for the temperature increase expansion of the limit sleeve 3 and the limit cap 4 to avoid excessive squeezing pressure between them.
[0025] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Based on the present invention and the above description, relevant personnel can make various changes and modifications without departing from the technical idea of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. An anti-loosening fastening connection pair that can be used for a steam turbine cylinder, characterized in that: It comprises a main stud (1), a main nut (2), a limiting sleeve (3) and a limiting cap (4); The side surface of one end of the main stud (1) is provided with a first external thread (101), and the side surface of the other end is provided with a second external thread (102); the main nut (2) can be screwed on the second external thread (102) of the main stud (1); one end surface of the main nut (2) is provided with at least one clamping groove (201); one end surface of the limiting sleeve (3) is fixedly connected with at least one clamping tooth (301); when the limiting sleeve (3) is sleeved on the second external thread (102) of the main stud (1), the clamping tooth (301) of the limiting sleeve (3) can fall into the clamping groove (201) of the main nut (2); The main stud (1) is provided with a threaded hole (103) at the end face close to the second external thread (102), and a secondary stud (401) is fixedly connected at the center of the inner side of the limiting cap (4). When the limiting cap (4) is sleeved on the corresponding end of the main stud (1), the secondary stud (401) of the limiting cap (4) can be screwed into the threaded hole (103) of the main stud (1), and the lower end face of the limiting cap (4) can conflict with the upper end face of the limiting sleeve (3).
2. The anti-loosening fastening connection pair that can be used for a steam turbine cylinder according to claim 1 is characterized in that: The internal thread of the main stud threaded hole (103) and the second external thread (102) thereof have opposite thread directions.
3. The anti-loosening fastening connection pair for a steam turbine cylinder according to claim 1 or 2, characterized in that: It also comprises an elastic buffer gasket (5), wherein the elastic buffer gasket (5) is arranged between the limiting sleeve (3) and the limiting cap (4).