Muffle end cover pre-tightening mechanism
By using an elastic pre-tightening component surrounding the connecting shaft in the muffle end cap pre-tightening mechanism, the problems of sealing performance and service life are solved, achieving uniform force distribution on the sealing surface and a stable sealing effect, thus extending the service life of the inner furnace door.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-14
- Publication Date
- 2026-03-06
AI Technical Summary
In the prior art, the sealing performance and service life of the muffle end cap are affected by uneven force when the inner furnace door and the inner furnace are fitted together, resulting in a decrease in sealing effect and deformation or cracking of the inner furnace door.
The muffle end cap pre-tightening mechanism includes an end cap, a fixing frame, an inner furnace door, and a pre-tightening assembly. The pre-tightening assembly, consisting of screws, locking nuts, adjusting sleeves, and springs evenly distributed around the connecting shaft, achieves elastic pressure, compensates for machining errors and assembly deviations, ensures uniform force on the sealing surface, and automatically adjusts the contact pressure of the sealing surface when the temperature changes.
It significantly improves sealing reliability, reduces the risk of deformation and cracking of the inner furnace door, extends service life, and ensures the stability of the sealing surface under temperature changes and external impacts.
Smart Images
Figure CN223976461U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of sintering equipment technology, and in particular to a muffle end cap pre-tightening mechanism. Background Technology
[0002] As a core piece of equipment in high-temperature material processing, the sealing performance of a vacuum heat treatment furnace has a crucial impact on the stability of the furnace environment and energy utilization efficiency. The muffle end cap, as a key sealing component in the vacuum heat treatment furnace, plays a vital role in ensuring the airtightness of the furnace environment. Currently, the muffle end cap is designed to connect its center to the inner furnace door via a connecting shaft, relying on the inner furnace door to achieve a seal within the furnace body. However, this connection structure and sealing method have the following defects and shortcomings:
[0003] During the fitting process between the inner furnace door and the inner furnace, uneven force distribution can easily lead to a decrease in sealing effect. At the same time, this uneven force state may also cause excessive pressure on the inner furnace door in some areas, which may lead to deformation or even cracking of the inner furnace door, seriously affecting its service life.
[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content
[0005] (a) Technical problems to be solved
[0006] This application provides a muffle end cap pre-tightening mechanism, which can solve the problem of how to improve the sealing performance and service life of muffle end caps in the prior art.
[0007] (II) Technical Solution
[0008] To solve the above-mentioned technical problems, this application provides the following technical solution:
[0009] A muffle end cap pre-tightening mechanism is provided, the muffle end cap pre-tightening mechanism includes: an end cap, a fixing frame, an inner furnace door, and a pre-tightening assembly;
[0010] The fixed frame and the inner furnace door are respectively located on opposite sides of the end cover. The end cover is fixedly connected to the fixed frame and has a bushing at the center position. The inner furnace door has a connecting shaft at the center position and can slide axially with the bushing through the connecting shaft. There is an movable gap between the inner furnace door and the end cover.
[0011] The pre-tightening assembly has at least three sets and is evenly distributed around the connecting shaft. The pre-tightening assembly includes a screw, a locking nut, an adjusting sleeve, a spring, and a sleeve seat. The sleeve seat is fixedly disposed on the side of the fixing frame away from the end cover, and has an axially extending shaft cavity inside. The spring is disposed at one end of the shaft cavity away from the end cover. One end of the screw is fixedly connected to the inner furnace door through the locking nut, and the other end moves through the end cover and the fixing frame and extends into the shaft cavity. The adjusting sleeve is movably disposed in the shaft cavity, and one end of it is threadedly connected to the screw, and the other end is in contact with the spring.
[0012] In some embodiments, the end of the shaft cavity opposite to the end cap is provided with an air hole.
[0013] In some embodiments, the preload assembly further includes a limiting sleeve disposed in the shaft cavity, the limiting sleeve being sleeved on the outside of the screw and located on the side of the adjusting screw sleeve near the sleeve seat, and the limiting sleeve having an annular retaining ring abutting against the fixing frame.
[0014] In some embodiments, the preload assembly further includes a limiting ring, which is sleeved on the outside of the screw and located between the limiting sleeve and the adjusting sleeve.
[0015] In some embodiments, two locking nuts are provided and are respectively provided on both sides of the inner furnace door. The inner furnace door is provided with a through hole, and at least one nut is provided on each side of the through hole. The end of the screw passes through the through hole and is fixedly connected to the inner furnace door by the locking nuts distributed on both sides of the through hole.
[0016] In some embodiments, the fixing frame includes a central seat, fixing rods, and an outer ring. Several fixing rods are provided and radially fixed to the outside of the central seat. The outer ring is centered on the central seat and fixedly connected to each of the fixing rods. The end cap is fixedly disposed on the inner side of the outer ring. The bushing is fixedly installed on the central seat and passes through the end cap. The sleeve is fixedly installed on the fixing rods.
[0017] In some embodiments, the fixing rod is provided with a tube seat, the tube seat is provided with an internal threaded hole, and one end of the sleeve is provided with an external thread, which is threadedly connected to the internal threaded hole.
[0018] In some embodiments, the end cap is provided with a recessed groove whose shape and size are adapted to the inner furnace door; when the end cap is closed, the inner furnace door is located inside the recessed groove; the recessed groove is provided with a clearance groove opposite to the position of the locking nut.
[0019] (III) Beneficial Effects
[0020] Compared with the prior art, the beneficial effects of the technical solution provided in this application include at least the following:
[0021] The pre-tightening mechanism of this application allows for individual adjustment of the axial displacement of the corresponding screw by rotating each adjusting sleeve, thus changing the spring compression as needed. This precisely controls the force applied to each component, compensating for differences in pre-tightening force caused by machining errors or assembly deviations. It reduces pressure differences in different areas of the inner furnace door in traditional single-axis connection structures, ensuring uniform force distribution on the sealing surface and significantly improving sealing reliability. Simultaneously, when temperature changes cause variations in the gap between the inner furnace door and the inner furnace opening, the elastic restoring force of the spring automatically adjusts the inner furnace door displacement, maintaining the stability of the contact pressure on the sealing surface.
[0022] Equally important, the spring undergoes linear deformation when compressed within the shaft cavity, transforming rigid locking into elastic preload. When the inner furnace expands due to heat or is subjected to external impact, the spring absorbs excessive displacement through its own deformation, thereby reducing the risk of the inner furnace door bearing excessive load. In other words, the muffle end cap preload mechanism of this application replaces traditional rigid locking with elastic pressure, reducing the risk of inner furnace door deformation or cracking caused by localized stress concentration and extending the service life of the components. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a schematic diagram of the muffle end cap pre-tightening mechanism in an embodiment of this application;
[0025] Figure 2 This is a side view of the muffle end cap pretensioning mechanism in an embodiment of this application;
[0026] Figure 3 This is a front view of the muffle end cap pretensioning mechanism in the embodiments of this application;
[0027] Figure 4 yes Figure 3 A sectional view of section A in the middle;
[0028] Figure 5 yes Figure 4 A schematic diagram of region B in the middle.
[0029] Figure label:
[0030] End cap 1, first guide hole 11, countersunk groove 12, clearance groove 13;
[0031] 2. Fixing bracket, 21. Bushing, 22. Tube seat, 23. Center seat, 24. Fixing rod, 25. Outer ring;
[0032] Inner furnace door 3, connecting shaft 31, through hole 32;
[0033] Preload assembly 4, screw 41, lock nut 42, adjusting screw sleeve 43, spring 44, sleeve 45, shaft cavity 451, air hole 452, limit sleeve 46, annular retaining ring 461, limit ring 47;
[0034] Inner furnace 5.
[0035] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation
[0036] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.
[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.
[0038] As a core piece of equipment for high-temperature material processing, the sealing performance of the inner furnace of a vacuum heat treatment furnace directly affects the stability of the furnace atmosphere and energy utilization efficiency. The muffle end cap is a key sealing component of the inner furnace. Currently, the muffle end cap is connected to the inner furnace door via a connecting shaft, sealing the inner furnace through the inner furnace door. This connection structure and sealing / waterproofing have the following defects and shortcomings: when the inner furnace door and the inner furnace are in contact, uneven stress can easily reduce the sealing effect; simultaneously, the inner furnace door is prone to localized excessive stress due to uneven stress, leading to deformation and cracking, thus affecting its service life.
[0039] To address the aforementioned technical problems, this embodiment provides a muffle end cap pre-tightening mechanism. (See reference...) Figures 1 to 5 As shown, Figure 1 This is a schematic diagram of the muffle end cap pre-tightening mechanism in an embodiment of this application. Figure 2 This is a side view of the muffle end cap pretensioning mechanism in an embodiment of this application. Figure 3 This is a front view of the muffle end cap pretensioning mechanism in an embodiment of this application. Figure 4 yes Figure 3 Sectional view of section A in the middle. Figure 5 yes Figure 4 A schematic diagram of region B in the middle.
[0040] The pre-tightening mechanism of the end cap in this embodiment includes: end cap 1, fixing frame 2, inner furnace door 3, and pre-tightening component 4.
[0041] like Figure 4 As shown, the fixed frame 2 and the inner furnace door 3 are respectively located on the two end faces of the end cover 1. The end cover 1 is fixedly connected to the fixed frame 2 and a bushing 21 is provided at the center position. The inner furnace door 3 is provided with a connecting shaft 31 at the center position, and the connecting shaft 31 and the bushing 21 can be axially slidably engaged. There is an movable gap between the inner furnace door 3 and the end cover 1 for the inner furnace door 3 to move.
[0042] like Figure 3 As shown, the pre-tightening assembly 4 has at least three sets, evenly distributed around the connecting shaft 31. For example, the pre-tightening assembly 4 has three sets, spaced 120° apart. The pre-tightening assembly 4 includes a screw 41, a locking nut 42, an adjusting sleeve 43, a spring 44, and a sleeve 45. The sleeve 45 is fixedly mounted on the side of the fixing frame 2 away from the end cover 1, and has an axially extending shaft cavity 451 inside. The spring 44 is located at the end of the shaft cavity 451 away from the end cover 1. One end of the screw 41 is fixed to the inner furnace door 3 by the locking nut 42, and the other end moves through the end cover 1 and the fixing frame 2 and extends into the shaft cavity 451. Specifically, the end cover 1 has a first guide hole 11, and the screw 41 is clearance-fitted with the first guide hole 11. The adjusting sleeve 43 is movably mounted in the shaft cavity 451, and one end is threadedly connected to the screw 41, while the other end abuts against the spring 44.
[0043] When the end cover 1 closes the inner furnace door, the spring 44 pushes the inner furnace door 3 through the adjusting sleeve 43 and the screw 41, so that the inner furnace door 3 elastically abuts against the opening of the inner furnace 5. At least three sets of pre-tightening components 4 evenly distributed around the central axis constitute a dynamic pressure application structure: the screws 41 of each pre-tightening component 4 are radially and angularly distributed, and the elastic potential energy of the spring 44 is converted into axial thrust through the threaded adjusting sleeve 43. When the end cover 1 is closed, the coordinated pushing of multiple sets of springs 44 makes the sealing surface of the inner furnace door 3 and the opening of the inner furnace 5 achieve uniform contact in the entire circumference, eliminating the edge stress concentration phenomenon of the traditional single-axis structure. The compression deformation of the spring 44 in the shaft cavity 451 generates a linear restoring force, which is transmitted to the screw 41 through the adjusting sleeve 43 and finally acts on the inner furnace door 3. This elastic pressure application method can automatically compensate for the thermal expansion difference between the inner furnace door 3 and the opening of the inner furnace 5, avoiding deformation caused by rigid connection.
[0044] In some embodiments of the sleeve 45, see [reference]. Figure 5As shown, the shaft cavity 451 has an air hole 452 at one end away from the end cover 1, allowing the gas inside the cavity to flow freely during the compression of the spring 44. This structure eliminates the influence of air resistance on the dynamic response of the spring 44, ensures the linearity of the preload adjustment, and prevents pressure interference caused by gas expansion under high temperature conditions.
[0045] In some embodiments of the pretensioning component 4, see [reference]. Figure 4 and Figure 5 As shown, the preload assembly 4 also includes a limiting sleeve 46 disposed within the shaft cavity 451. The limiting sleeve 46 is fitted around the outside of the screw 41 and is located on the side of the adjusting screw sleeve 43 near the sleeve base 45. The limiting sleeve 46 has an annular retaining ring 461 that abuts against the fixing frame 2. In other words, a limiting sleeve 46 fitted around the outside of the screw 41 is added inside the shaft cavity 451 of the sleeve base 45, and the annular retaining ring 461 at its end forms a rigid stop with the fixing frame 2. When the spring 44 pushes the screw 41, the limiting sleeve 46 abuts against the fixing frame 2 to prevent further displacement, providing safety protection for the elastic preload structure.
[0046] Further, see Figure 4 and Figure 5 As shown, the preload assembly 4 also includes a limiting ring 47, which is sleeved on the outside of the screw 41 and located between the limiting sleeve 46 and the adjusting sleeve 43. The limiting ring 47, fitted onto the screw 41, is positioned between the limiting sleeve 46 and the adjusting sleeve 43, with its inner hole having a clearance fit with the screw 41 to form a radial guide structure. The limiting ring 47 suppresses lateral swaying of the screw 41 during the pressure application process, ensuring the linear transmission of axial thrust and reducing preload attenuation caused by frictional losses.
[0047] In one embodiment where one end of the screw 41 is fixed to the inner furnace door 3 by a locking nut 42, see [reference needed]. Figure 4 and Figure 5 As shown, two locking nuts 42 are provided, located on both sides of the inner furnace door 3 respectively. The end of the screw 41 passes through the through hole 32 provided in the inner furnace door 3, and axial fixation and circumferential anti-rotation are achieved by the two locking nuts 42 distributed on both sides of the through hole 32. The double nut interlocking mechanism not only prevents the preload from loosening due to the circumferential rotation of the screw 41, but also allows for fine adjustment of the relative position of the inner furnace door 3 and the screw 41, eliminating the influence of cumulative assembly errors on the parallelism of the sealing surface.
[0048] In one embodiment of the aforementioned fixing bracket 2, see [reference needed]. Figure 1 and Figure 4As shown, the fixing frame 2 includes a central seat 23, fixing rods 24, and an outer ring 25. Several fixing rods 24 are radially fixed to the outside of the central seat 23. The outer ring 25 is centered on the central seat 23 and fixedly connected to each fixing rod 24. The end cap 1 is fixedly disposed inside the outer ring 25. A bushing 21 is fixedly mounted on the central seat 23 and passes through the end cap 1. A sleeve 45 is fixedly mounted on the fixing rods 24. For example, the outer ring 25 is clamped around the periphery of the end cap 1 and is welded or riveted to the end cap 1. This fixing frame structure evenly distributes the concentrated load applied by the pre-tightening assembly 4 along the fixing rods 24, significantly reducing the bending stress on the end cap 1 body. The design of the bushing 21 penetrating the end cap 1 and being mounted on the central seat 23 ensures the coaxiality of the sliding trajectory of the inner furnace door 3 with the force direction of the pre-tightening assembly 4.
[0049] Further, see Figure 4 and Figure 5 As shown, the aforementioned sleeve 45 can be fixedly mounted on the side of the fixing frame 2 away from the end cover 1 in the following way: a tube seat 22 is provided on the fixing rod 24, and an internal threaded hole is provided in the tube seat 22. An external thread is provided on the outer side of one end of the sleeve 45, and it is threadedly connected to the tube seat 22. This detachable connection method of the sleeve 45 facilitates the independent maintenance and replacement of the pre-tightening component 4. At the same time, the self-locking characteristic of the threaded engagement maintains the stability of the force direction and avoids loosening of the connection due to vibration.
[0050] In some implementations, see Figure 4 and Figure 5 As shown, the end cap 1 has a recess 12 whose shape and size are adapted to the inner furnace door 3; when the end cap 1 is closed, the inner furnace door 3 is located inside the recess 12, forming a secondary sealing interface; the recess 12 has a clearance groove 13 opposite to the position of the locking nut 42. The clearance groove 13 on the side wall of the recess 12 provides clearance space for the locking nut 42, ensuring that the inner furnace door 3 can slide freely along the axial direction without interference, while limiting its radial offset within the allowable sealing tolerance range.
[0051] In summary, the pre-tightening mechanism of this application allows for individual adjustment of the axial displacement of the corresponding screw 41 by rotating each adjusting sleeve 43, thereby changing the compression of the spring 44 as needed. This precisely controls the force applied by each component, compensates for differences in pre-tightening force caused by machining errors or assembly deviations, reduces pressure differences in different areas of the inner furnace door 3 in traditional single-axis connection structures, ensures uniform force on the sealing surface, and significantly improves sealing reliability. Simultaneously, when temperature changes cause variations in the gap between the inner furnace door 3 and the inner furnace 5 opening, the elastic restoring force of the spring 44 automatically adjusts the displacement of the inner furnace door 3, maintaining the stability of the contact pressure on the sealing surface. Equally important, the spring 44 undergoes linear deformation when compressed within the shaft cavity 451, transforming rigid locking into elastic pre-tightening. When the inner furnace 5 expands due to heat or is impacted by external forces, the spring 44 absorbs excessive displacement through its own deformation, thereby reducing the risk of the inner furnace door 3 bearing excessive loads. In other words, the pre-tightening mechanism of the muffle end cap in this application replaces the traditional rigid locking with elastic pressure, reducing the risk of deformation or cracking of the inner furnace door 3 caused by local stress concentration and extending the service life of the components.
[0052] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A maran end cap pre-tensioning mechanism, characterized by, The utility model relates to a kind of pre-tightening assemblies of oven door, including: End cap, fixed frame, inner furnace door and pre-tightening assembly; The fixed frame and inner furnace door are respectively arranged on the opposite sides of the end cap, the end cap is fixedly connected with the fixed frame, and a shaft sleeve is arranged at the center position of the end cap, the inner furnace door is provided with a connecting shaft at the center position, and the connecting shaft is axially slidably matched with the shaft sleeve, and an active gap is arranged between the inner furnace door and the end cap; The pre-tightening assembly is provided with at least three groups and is uniformly arranged around the connecting shaft, and the pre-tightening assembly includes a screw rod, a locking nut, an adjusting sleeve, a spring and a sleeve seat, the sleeve seat is fixedly arranged on the side of the fixed frame away from the end cap, and an axially extending shaft cavity is arranged in the sleeve seat, the spring is arranged at the end of the shaft cavity away from the end cap, one end of the screw rod is fixedly connected with the inner furnace door through the locking nut, the other end of the screw rod is movably arranged through the end cap and the fixed frame and extends into the shaft cavity, and the adjusting sleeve is movably arranged in the shaft cavity, one end of the adjusting sleeve is threadedly connected with the screw rod, and the other end of the adjusting sleeve is in contact with the spring.
2. The marve! end cap pre-tensioning mechanism of claim 1, wherein, An air hole is arranged at the end of the shaft cavity away from the end cap.
3. The marve! end cap pre-tensioning mechanism of claim 1, wherein, The pre-tightening assembly further includes a limiting sleeve arranged in the shaft cavity, the limiting sleeve is arranged outside the screw rod and is located on the side of the adjusting sleeve close to the sleeve seat, and the limiting sleeve is provided with an annular stop ring abutting against the fixed frame.
4. The marve! end cap pre-tensioning mechanism of claim 3, wherein, The pre-tightening assembly further includes a limiting ring, the limiting ring is arranged outside the screw rod and is located between the limiting sleeve and the adjusting sleeve.
5. The marve! end cap pre-tensioning mechanism of claim 1, wherein, Two locking nuts are arranged on the two sides of the inner furnace door respectively, the inner furnace door is provided with a through hole, at least one nut is arranged on each side of the through hole, the end of the screw rod penetrates through the through hole and is fixedly connected with the inner furnace door through the locking nuts arranged on the two sides of the through hole.
6. The marve! end cap pre-tensioning mechanism of claim 1, wherein, The fixed frame includes a center seat, a plurality of fixed rods and an outer ring, the fixed rods are radially fixed outside the center seat, the outer ring is arranged around the center seat and is fixedly connected with the fixed rods, and the end cap is fixedly arranged inside the outer ring, the shaft sleeve is fixedly arranged on the center seat and penetrates through the end cap, and the sleeve seat is fixedly arranged on the fixed rods.
7. The marve! end cap pre-tensioning mechanism of claim 6, wherein, A pipe seat is arranged on the fixed rod, an internal thread hole is arranged in the pipe seat, an external thread is arranged on the outside of one end of the sleeve seat and is threadedly connected with the internal thread hole.
8. The marve! end cap pre-tensioning mechanism of claim 1, wherein, The end cap is provided with a recessed groove matching the shape and size of the inner furnace door, when the end cap is closed, the inner furnace door is located inside the recessed groove, and a clearance groove is arranged in the recessed groove opposite to the position of the locking nut.