Distance measuring assembly, pressure maintaining tool and battery cell pressure maintaining system
By designing the distance measuring component and using the relative displacement measurement of the first distance measuring part and the second distance measuring part, the problem of difficulty in accurately measuring the pressing distance of the battery module is solved, and the accurate pressure maintaining state of the battery module is achieved. Judgment and correct lamination.
Patent Information
- Application Number
- CN202420681803.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-02
- Publication Date
- 2025-01-21
- Estimated Expiration
- 2034-04-02
AI Technical Summary
The prior art is difficult to accurately measure the downward pressure distance of the battery cell module, which makes it difficult to judge the pressure magnitude, and it is easy to cause excessive pressure to deform the product or excessive pressure to be too small to be pressed open.
Design a distance measuring component, including a first distance measuring part and a second distance measuring part. By measuring the relative displacement of the two, the relative displacement between different structures can be accurately measured, thereby determining the pressure state of the pressure-maintained part.
It achieves accurate measurement of the pressure-holding state of the battery module, avoids the problem of too high or too low pressure, and ensures the correct pressing of the battery module.
Smart Images
Figure CN222380616U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of battery core pressure maintenance, in particular to a distance measuring component, a pressure maintenance tool and a battery core pressure maintenance system. Background Art
[0002] After the battery cell module is placed in the box, the module needs to be pressurized. However, due to the staggered arrangement of the components of the pressure-holding tooling and the irregular shapes of the components, it is difficult to directly and accurately measure the downward pressure distance of the module, and thus it is difficult to accurately judge whether the pressure is appropriate. It is easy for the pressure to be too high, resulting in product deformation, or the pressure to be too low and the glue cannot be pressed open. Utility Model Content
[0003] The purpose of the invention of the utility model is to provide a distance measuring component, a pressure maintaining tooling and a battery cell pressure maintaining system to address the problems existing in the prior art, which can conveniently and accurately measure the relative displacement between different structures and provide a basis for judging the pressure state of the pressure-maintained parts.
[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is:
[0005] A distance measuring component comprises a first distance measuring component and a second distance measuring component; the first distance measuring component is installed on a first structure, and the second distance measuring component is installed on a second structure, and the first structure and the second structure can approach or move away from each other; the first distance measuring component and the second structure can move relative to each other, and the free ends of the first distance measuring component and the second distance measuring component are both located on the side of the second structure away from the first structure.
[0006] The distance measuring assembly provided by the present application is provided with a first distance measuring member and a second distance measuring member, and the free ends of the first distance measuring member and the second distance measuring member are both located on the side of the second structure away from the first structure; by measuring the relative displacement of the first distance measuring member and the second distance measuring member, the displacement distance between the first structure and the second structure can be obtained, which can be used to solve the distance measurement difficulties caused by the complex shapes and positional relationships of the first structure and / or the second structure.
[0007] The distance measuring component provided in the present application can be used for pressure-maintaining tooling, can provide a measurement basis for judging the state of the pressure-maintained part, and has the characteristics of simple setting and convenient measurement.
[0008] As a preferred solution of the present utility model, the first distance measuring component and the second distance measuring component are arranged close to each other.
[0009] The close arrangement is conducive to measuring the relative displacement of the first distance measuring member and the second distance measuring member.
[0010] As a preferred solution of the present utility model, in the vertical direction of the distance measuring direction, the projections of the first distance measuring component and the second distance measuring component have an overlapping portion.
[0011] The caliper can be directly inserted between the first distance measuring member and the second distance measuring member to conveniently read the distance between the first distance measuring member and the second distance measuring member in the distance measuring direction.
[0012] As a preferred solution of the utility model, the second distance measuring member includes a top cover, the free end of the first distance measuring member is located on a side of the top cover close to the second structure, and in the vertical direction of the distance measuring direction, the projections of the first distance measuring member and the top cover have an overlapping portion;
[0013] The surfaces opposite to the top cover and the first distance measuring component are both planes, and the surfaces opposite to the top cover and the first distance measuring component are both perpendicular to the distance measuring direction.
[0014] The top cover is arranged on the second distance measuring member, and the free end of the first distance measuring member is located on the side of the top cover close to the second structure, which will not hinder the first structure and the second structure from moving away from each other, and is conducive to the flexible arrangement of the first structure and the second structure; the opposite surfaces of the top cover and the first distance measuring member are planes and perpendicular to the distance measuring direction, which is convenient for caliper measurement and makes the measurement result more accurate.
[0015] As a preferred solution of the utility model, there is a space between the first distance measuring member and the top cover for the caliper to extend into.
[0016] The present application also provides a pressure-maintaining tool, including a pressure-maintaining plate and the distance measuring assembly as described above, wherein the pressure-maintaining plate is a first structure.
[0017] The pressure-maintaining tooling provided in the present application, due to the use of the distance measuring assembly as described above, can more conveniently measure the displacement distance of the pressure-maintaining plate in the tooling, thereby providing a basis for determining whether the pressure-maintaining plate has reached a predetermined position.
[0018] As a preferred solution of the utility model, the pressure-maintaining tooling also includes a base, and the base and the pressure-maintaining plate can be close to or away from each other, and the base is the second structure.
[0019] The pressure-maintaining tooling provided in the present application, due to the use of the distance measuring component as described above, can directly and accurately measure and read the moving distance of the pressure-maintaining plate relative to the base when the pressure-maintaining plate moves relative to the base, thereby providing a basis for determining whether the pressure-maintaining plate has reached a predetermined position.
[0020] As a preferred solution of the utility model, the number of distance measuring components is two, and the two distance measuring components are centrally symmetrically distributed with the pressure maintaining plate as the center.
[0021] It is possible to determine whether the pressure holding plate is skewed while measuring the distance.
[0022] The present application also provides a battery cell pressure maintaining system, including a battery cell module and the pressure maintaining tooling as described above, wherein the battery cell module and the pressure maintaining plate are arranged relative to each other.
[0023] The battery cell pressure-maintaining system provided in the present application uses the pressure-maintaining tooling as described above to maintain the pressure of the battery cell module. During the movement of the pressure-maintaining plate, the moving distance of the pressure-maintaining plate can be directly and accurately measured and read. By comparing it with the theoretical distance, it can be determined whether the pressure-maintaining plate has moved too much or too little, thereby determining whether the glue has been pressed open, and avoiding deformation of the battery cell module due to excessive pressing force.
[0024] As a preferred solution of the utility model, the battery cell pressure maintaining system includes a mounting seat, the mounting seat has a placement portion, and the battery cell module is placed on the placement portion; the base can be fixedly connected to the mounting seat, and the pressure maintaining plate can approach and press the battery cell module; during the pressure maintaining process, the free ends of the first distance measuring member and the second distance measuring member are both located on the side of the base away from the pressure maintaining plate.
[0025] In summary, due to the adoption of the above technical solution, the beneficial effects of the utility model are:
[0026] 1. The distance measuring assembly provided by the present application is provided with a first distance measuring member and a second distance measuring member, and the free ends of the first distance measuring member and the second distance measuring member are both located on the side of the second structure away from the first structure; so that the displacement distance between the first structure and the second structure can be obtained by measuring the relative displacement of the first distance measuring member and the second distance measuring member, which can be used to solve the distance measurement difficulties caused by the complex shape and position relationship of the first structure and / or the second structure; the distance measuring assembly provided by the present application can be used for the pressure holding tooling, can provide a measurement basis for judging the state of the pressure-held part, and has the characteristics of simple setting and convenient measurement.
[0027] 2. The pressure-maintaining tooling provided in the present application, because it uses the distance measuring assembly as described above, can more conveniently measure the displacement distance of the pressure-maintaining plate in the tooling, thereby providing a basis for determining whether the pressure-maintaining plate has reached a predetermined position.
[0028] 3. The battery cell pressure-maintaining system provided in the present application uses the pressure-maintaining tooling as described above to maintain the pressure of the battery cell module. During the movement of the pressure-maintaining plate, it is possible to directly and accurately measure the moving distance of the pressure-maintaining plate, and compare it with the theoretical distance. It can be determined whether the pressure-maintaining plate has moved too much or too little, thereby determining whether the glue has been pressed open, thereby avoiding deformation of the battery cell module due to excessive pressing force. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 It is a structural schematic diagram of the distance measuring component of the utility model;
[0030] Figure 2 This is a schematic diagram of the structure of the pressure-maintaining tooling of the utility model;
[0031] Figure 3 It is a top view of the pressure-maintaining tooling of the utility model;
[0032] Figure 4 It is a side view of the pressure-maintaining tooling of the utility model;
[0033] Figure 5 This is a structural schematic diagram of the battery core pressure maintaining system of the utility model;
[0034] Figure 6 for Figure 5 Side view of
[0035] Figure 7 This is another structural schematic diagram of the battery core pressure maintaining system of the utility model;
[0036] Figure 8 for Figure 7 Side view of.
[0037] Markings in the figure: 10-distance measuring assembly; 11-first distance measuring part; 12-second distance measuring part; 13-first structure; 14-second structure; 15-top cover; 20-base; 21-pressure maintaining plate; 22-connecting shaft; 23-driving device; 24-lifting ring; 25-fixing part; 30-mounting seat; 31-placing part; 32-fixed beam. DETAILED DESCRIPTION
[0038] The present invention is further described in detail below in combination with test examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.
[0039] In the description of the specific embodiments of the present invention, unless otherwise specified, the terms indicating the orientation or position relationship such as "upper", "lower", "left", "right", "center", "inside", "outside", etc. are all expressions based on the orientation or position relationship shown in the drawings, or the orientation or position relationship of the product / equipment / device of the utility model when it is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the utility model or simplifying the description in the specific embodiments, so that technicians can quickly understand the scheme, rather than indicating or implying that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.
[0040] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the solution of the utility model.
[0041] In addition, the expressions “first”, “second”, “third”, etc. that appear in the terms are merely descriptions used to distinguish the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.
[0042] In addition, in the description of the embodiments of the present invention, "several", "multiple" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.
[0043] In addition, in the description of the technical solution of the utility model, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal communication of two components.
[0044] Example 1
[0045] A distance measuring component 10, see Figure 1-4 , including a first distance measuring member 11 and a second distance measuring member 12; the first distance measuring member 11 is installed on a first structure 13, and the second distance measuring member 12 is installed on a second structure 14, and the first structure 13 and the second structure 14 can approach or move away from each other; the first distance measuring member 11 and the second structure 14 can move relative to each other, and the free ends of the first distance measuring member 11 and the second distance measuring member 12 are both located on the side of the second structure 14 away from the first structure 13.
[0046] The distance measuring assembly 10 provided in the present application is provided with a first distance measuring member 11 and a second distance measuring member 12, and the free ends of the first distance measuring member 11 and the second distance measuring member 12 are both located on the side of the second structure 14 away from the first structure 13; so that the displacement distance between the first structure 13 and the second structure 14 can be obtained by measuring the relative displacement of the first distance measuring member 11 and the second distance measuring member 12, which can be used to solve the distance measurement difficulties caused by the complex shapes and positional relationships of the first structure 13 and / or the second structure 14.
[0047] The distance measuring assembly 10 provided in the present application can be used in a pressure-maintaining tool, can provide a measurement basis for determining the pressure state of a pressure-maintained part, and has the characteristics of simple setting and convenient measurement.
[0048] The first distance measuring member 11 or the second distance measuring member 12 may be a structural member such as a block, a column or a rod.
[0049] One end of the first distance measuring member 11 is fixedly connected to the first structure 13, and the other end opposite to the fixedly connected end is the free end of the first distance measuring member 11; one end of the second distance measuring member 12 is fixedly connected to the second structure 14, and the other end opposite to the fixedly connected end is the free end of the second distance measuring member 12.
[0050] The first structure 13 and the second structure 14 may be two separate structural members, or may be two components on the same structure that can move relative to each other.
[0051] The first structure 13 and the second structure 14 can approach or move away from each other, and there are two situations: one situation is that the first structure 13 and the second structure 14 move relative to each other in the ranging direction; the other situation is that the relative movement of the first structure 13 and the second structure 14 has a displacement component in the ranging direction.
[0052] In space, there are many positional relationships between the two structures, which can be relative settings, semi-enclosed settings or enclosed settings. The first structure 13 and the second structure 14 can be flexibly selected from the two structures to try to make the side of the second structure 14 away from the first structure 13 an open space to facilitate subsequent measurements.
[0053] The first distance measuring member 11 is located at a side of the second structure 14 , or the first distance measuring member 11 passes through a through hole provided in the second structure 14 .
[0054] Preferably, the first distance measuring member 11 and the second distance measuring member 12 are arranged close to each other, so as to facilitate the measurement of the relative displacement between the first distance measuring member 11 and the second distance measuring member 12 .
[0055] The sides of the first distance measuring member 11 and the second distance measuring member 12 are close to each other, or the distance between them is less than 20 cm.
[0056] Example 2
[0057] The present embodiment provides a distance measuring component 10. Based on the embodiment 1, in the vertical direction of the distance measuring direction, the projections of the first distance measuring component 11 and the second distance measuring component 12 have an overlapping portion, and a caliper can be used to directly extend between the first distance measuring component 11 and the second distance measuring component 12 to more conveniently read the distance between the first distance measuring component 11 and the second distance measuring component 12 in the distance measuring direction.
[0058] Preferably, the second distance measuring member 12 includes a top cover 15, and the free end of the first distance measuring member 11 is located on a side of the top cover 15 close to the second structure 14, and in the vertical direction of the distance measuring direction, the projections of the first distance measuring member 11 and the top cover 15 have an overlapping portion.
[0059] The top cover 15 can be a block, a box or a hollow structure.
[0060] In the distance measuring direction, the distance between the free end of the first distance measuring member 11 and the second structure 14 may be greater than, equal to, or less than the distance between the free end of the second distance measuring member 12 and the second structure 14; in the present embodiment, the distance between the free end of the first distance measuring member 11 and the second structure 14 is less than the distance between the free end of the second distance measuring member 12 and the second structure 14, so that the free end of the first distance measuring member 11 is located on the side of the top cover 15 close to the second structure 14, which will not hinder the first structure 13 and the second structure 14 from moving away from each other, and is conducive to the flexible arrangement of the first structure 13 and the second structure 14.
[0061] Preferably, the opposing surfaces of the top cover 15 and the first distance measuring member 11 are both planes, and the opposing surfaces of the top cover 15 and the first distance measuring member 11 are both perpendicular to the distance measuring direction, which is convenient for caliper measurement and can make the measurement result more accurate.
[0062] On the basis of the above, it is further preferred that there is a space between the first distance measuring member 11 and the top cover 15 for the measuring claws in the caliper to extend into.
[0063] Example 3
[0064] A pressure-maintaining tool comprises a pressure-maintaining plate 21 and a distance-measuring assembly 10 as described in Embodiment 1 or 2, wherein the pressure-maintaining plate 21 is a first structure 13.
[0065] The pressure-maintaining tooling provided in this embodiment, because it uses the distance measuring assembly 10 as described above, can more conveniently measure the displacement of the pressure-maintaining plate in the tooling, thereby providing a basis for determining whether the pressure-maintaining plate 21 has reached a predetermined position.
[0066] Example 4
[0067] See also Figure 2-4This embodiment provides a pressure-maintaining tooling. Based on Embodiment 3, the pressure-maintaining tooling further includes a base 20 . The base 20 and the pressure-maintaining plate 21 can be close to or away from each other, and the base 20 is the second structure 14 .
[0068] The base 20 and the pressure maintaining plate 21 can be connected through a connecting shaft 22. For example, a through opening or a non-through slot can be set on the base 20, one end of the connecting shaft 22 is fixed to the pressure maintaining plate 21, and the other end is penetrated or half-penetrated into the base 20; a slide groove can also be set on the side of the base 20, and the connecting shaft 22 is slidably set in the slide groove.
[0069] A driving device 23 may be provided between the base 20 and the pressure-maintaining plate 21 to drive the pressure-maintaining plate 21 away from the base 20 . The driving device 23 may be an elastic member such as a spring, or may be an electric push rod, a cylinder, or other equipment.
[0070] One arrangement of the distance measuring assembly 10 is as follows: the first distance measuring component 11 is installed on the pressure maintaining plate 21, and the second distance measuring component 12 is installed on a bearing structure connected to the pressure maintained component. The first distance measuring component 11 extends out of the bearing structure so that the free ends of the first distance measuring component 11 and the second distance measuring component 12 are both located on the side of the bearing structure away from the pressure maintaining plate 21. The pressing state of the pressure maintained component is determined by measuring the relative displacement change between the pressure maintaining plate 21 and the bearing structure.
[0071] Another arrangement of the distance measuring assembly 10: the first distance measuring component 11 is installed on the pressure maintaining plate 21, and the second distance measuring component 12 is installed on the base 20. The base 20 and the bearing structure are fixedly connected, and the pressing state of the pressure maintained component is determined by measuring the relative displacement change between the pressure maintaining plate 21 and the base 20.
[0072] The second arrangement is preferred in this embodiment, where the pressure-maintaining plate 21 is the first structure 13, the base 20 is the second structure 14, and the side of the base 20 away from the pressure-maintaining plate 21 is an open space for easy measurement of readings.
[0073] The pressure-maintaining tooling provided in this embodiment uses the distance measuring assembly 10 as described above, and can directly and accurately measure and read the moving distance of the pressure-maintaining plate 21 relative to the base 20 when the pressure-maintaining plate 21 moves relative to the base 20, thereby providing a basis for determining whether the pressure-maintaining plate 21 has reached a predetermined position.
[0074] On the basis of the above, it is further preferred that the number of the distance measuring components 10 is two, and the two distance measuring components 10 are centrally symmetrically distributed with the pressure maintaining plate 21 as the center.
[0075] By measuring the readings of the two distance measuring components 10 , it is possible to determine whether the pressure maintaining plate 21 is deflected while measuring the distance.
[0076] Preferably, a hanging ring 24 is provided on a side of the base 20 facing away from the pressure maintaining plate 21 .
[0077] Example 5
[0078] A battery cell pressure maintenance system, see Figure 5-8 , including a battery cell module and a pressure maintaining tooling as described in Example 4, the battery cell module and the pressure maintaining plate 21 are arranged relative to each other.
[0079] The battery cell pressure-maintaining system provided in the present application uses the pressure-maintaining tooling as described above to maintain the pressure of the battery cell module. During the movement of the pressure-maintaining plate 21, the moving distance of the pressure-maintaining plate 21 can be directly and accurately measured and read. By comparing it with the theoretical distance, it can be determined whether the pressure-maintaining plate 21 has moved too much or too little, thereby determining whether the glue has been pressed open, and avoiding deformation of the battery cell module due to excessive pressing force.
[0080] Preferably, the battery cell pressure maintaining system comprises a mounting seat 30 , wherein the mounting seat 30 has a placement portion 31 , and the battery cell module is placed on the placement portion 31 .
[0081] The base 20 can be fixedly connected to the mounting base 30 . A fixing member 25 can be provided on the base 20 , and a fixing beam 32 can be provided on the mounting base 30 . The fixing member 25 extends out of the base 20 and is fixedly connected to the fixing beam 32 .
[0082] The fixing member 25 and the fixing beam 32 are detachably connected, such as a bolt connection or a snap connection.
[0083] During the pressure-maintaining process, the free ends of the first distance-measuring member 11 and the second distance-measuring member 12 are both located on a side of the base 20 away from the pressure-maintaining plate 21 .
[0084] Directions:
[0085] Before use, first confirm the theoretical spacing that can make the battery module be pressed together better. After the battery module is put into the box, install the pressure-maintaining tooling on the mounting seat 30 and align the pressure-maintaining plate 21 with the battery module. Use the driving device 23 to push the pressure-maintaining plate 21 away from the base 20. During the pushing process, use the inner measuring claw of the caliper to measure the distance between the first distance measuring piece 11 and the top cover 15, and compare it with the theoretical distance to decide whether to continue pushing the pressure-maintaining plate 21 to move.
[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A distance measuring component, characterized in that: It comprises a first distance measuring component (11) and a second distance measuring component (12); The first distance measuring component (11) is installed on a first structure (13), and the second distance measuring component (12) is installed on a second structure (14); the first structure (13) and the second structure (14) can be moved closer to or farther from each other; The first distance measuring member (11) and the second structure (14) are capable of relative movement, and the free ends of the first distance measuring member (11) and the second distance measuring member (12) are both located on a side of the second structure (14) facing away from the first structure (13).
2. The distance measuring component according to claim 1, characterized in that: The first distance measuring component (11) and the second distance measuring component (12) are arranged close to each other.
3. The distance measuring component according to claim 1, characterized in that: In the vertical direction of the distance measuring direction, the projections of the first distance measuring element (11) and the second distance measuring element (12) have an overlapping portion.
4. The distance measuring component according to claim 3, characterized in that: The second distance measuring member (12) comprises a top cover (15), the free end of the first distance measuring member (11) is located on a side of the top cover (15) close to the second structure (14), and in a vertical direction of the distance measuring direction, projections of the first distance measuring member (11) and the top cover (15) have an overlapping portion; The surfaces facing each other of the top cover (15) and the first distance measuring component (11) are both planes, and the surfaces facing each other of the top cover (15) and the first distance measuring component (11) are both perpendicular to the distance measuring direction.
5. The distance measuring component according to claim 4, characterized in that: There is a space between the first distance measuring member (11) and the top cover (15) for the caliper to extend into.
6. A pressure-maintaining tool, characterized in that: It comprises a pressure-maintaining plate (21) and a distance-measuring assembly (10) as claimed in any one of claims 1 to 5, wherein the pressure-maintaining plate (21) is a first structure (13).
7. The pressure-maintaining tool according to claim 6, characterized in that: It also includes a base (20), wherein the base (20) and the pressure-maintaining plate (21) can be moved closer to or farther from each other, and the base (20) is a second structure (14).
8. The pressure-maintaining tool according to claim 7, characterized in that: The number of the distance measuring components (10) is two, and the two distance measuring components (10) are centrally symmetrically distributed with the pressure maintaining plate (21) as the center.
9. A battery cell pressure maintaining system, characterized in that: It comprises a battery cell module and a pressure-maintaining tool as claimed in any one of claims 7 to 8, wherein the battery cell module and the pressure-maintaining plate (21) are arranged relative to each other.
10. The battery cell pressure maintaining system according to claim 9, characterized in that: It comprises a mounting seat (30), the mounting seat (30) having a placement portion (31), and the battery core module is placed on the placement portion (31); The base (20) can be fixedly connected to the mounting base (30), and the pressure-maintaining plate (21) can be close to and press-fit the battery core module; During the pressure-maintaining process, the free ends of the first distance-measuring member (11) and the second distance-measuring member (12) are both located on a side of the base (20) facing away from the pressure-maintaining plate (21).