CN114659704A

CN114659704A - Shockproof diaphragm pressure gauge

Info

Publication number: CN114659704A
Application number: CN202210443802.4A
Authority: CN
Inventors: 王本举; 李传友; 戴华章; 梁福秋; 袁学慧; 曹爱民; 张俊; 段桂梅; 汪清; 陈鸿清
Original assignee: Anhui Tiankang Group Co Ltd
Current assignee: Anhui Tiankang Group Co Ltd
Priority date: 2022-04-26
Filing date: 2022-04-26
Publication date: 2022-06-24

Abstract

The invention relates to the technical field of pressure gauges, in particular to a shock-proof diaphragm pressure gauge which comprises a shell, wherein a display port is formed in one side of the shell, and a light-transmitting glass plate is arranged at the display port; the glass plate is detachably connected with a mounting plate on one side of the watchcase, which is far away from the glass plate, a core component, a pressure display plate and a pointer are arranged on the mounting plate, a support sleeve is integrally formed on the watchcase, the lower end of the support sleeve is connected with a flange plate, and the lower end of the flange plate is provided with a detection tube; a pressure gauge diaphragm is arranged on the inner side of the flange plate; the detection tube is communicated with the lower end of the pressure gauge diaphragm; an upper connecting column is arranged on the upper side of the pressure gauge diaphragm, a connecting rod piece is arranged on the inner side of the supporting sleeve, and two ends of the connecting rod piece are respectively connected with the upper connecting column and the movement part; the inner side of the watchcase is filled with shock-proof silicone oil, and a sealing rubber plug is arranged in the supporting sleeve. Through the scheme, the shock resistance of the pressure gauge can be improved, and the accuracy value of pressure gauge detection is further improved.

Description

Shockproof diaphragm pressure gauge

Technical Field

The invention relates to the technical field of pressure gauges, in particular to a shock-proof diaphragm pressure gauge.

Background

As is known, pressure change refers to a meter which takes an elastic element as a sensitive element and measures and indicates a pressure higher than the ambient pressure, and the application is very common, and the pressure change is almost spread in all fields of industrial processes and scientific research. The method is widely available in the fields of heating power pipe networks, oil and gas transmission, water and gas supply systems, vehicle maintenance plants and shops and the like. Especially in the industrial process control and technical measurement process, the mechanical pressure gauge is more and more widely applied due to the characteristics of high mechanical strength, convenient production and the like of the elastic sensitive element of the mechanical pressure gauge.

In recent years, in energy markets at home and abroad, the on-site pressure gauge is more and more emphasized by users, and the national standard also increases the forced detection of the pressure gauge. The pressure of a fluid pipeline in a petrochemical field is below 10Kpa, a medium contains acid and sulfur corrosiveness, vibration and the like are generated when some equipment and devices operate under micro pressure, and the pressure value cannot be measured with high precision by using a common pressure gauge.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides the shock-resistant diaphragm pressure gauge which can improve the shock resistance of the pressure gauge and further improve the detection accuracy of the pressure gauge.

(II) technical scheme

In order to achieve the above object, an embodiment of the present application provides an earthquake-resistant diaphragm pressure gauge, which includes a case, wherein a display port is formed at one side of the case, and a transparent glass plate is arranged at the display port; the watchcase is kept away from one side of glass board can dismantle and be connected with the mounting panel set up organic core part, pressure display board and pointer on the mounting panel, its characterized in that: a support sleeve is integrally formed on the watch case, the lower end of the support sleeve is connected with a flange plate, and the lower end of the flange plate is provided with a detection tube; a pressure gauge diaphragm is arranged on the inner side of the flange plate; the detection tube is communicated with the lower end of the pressure gauge diaphragm; an upper connecting column is arranged on the upper side of the pressure gauge diaphragm, a connecting rod piece is arranged on the inner side of the supporting sleeve, and two ends of the connecting rod piece are respectively connected with the upper connecting column and the movement part; the inner side of the watch case is filled with shock-proof silicone oil, and a sealing rubber plug is arranged in the supporting sleeve.

Preferably, the connecting rod piece comprises a threaded rod and a connecting sleeve; the connecting sleeve comprises a first pipe section and a second pipe section, the first pipe section and the second pipe section are integrally formed, and the first pipe section is positioned on the lower side of the sealing rubber plug; the upper end of the threaded rod is in threaded connection with the first pipe section; the lower end of the core part is connected with a connecting rod, and the connecting rod penetrates through the sealing rubber plug and is detachably connected with the second pipe section.

Preferably, a locking hole is formed in the side wall of the second pipe section, a locking screw is connected to the locking hole in a threaded manner, and one end of the locking screw penetrates through the locking hole and abuts against the connecting rod on the inner side of the second pipe section.

Preferably, the sealing rubber plug comprises a first rubber sleeve and a second rubber sleeve which are positioned on the inner side of the supporting sleeve, the first rubber sleeve and the second rubber sleeve are integrally formed, and the outer diameter of the first rubber sleeve is larger than that of the second rubber sleeve; the first rubber sleeve is detachably and hermetically connected with the support sleeve, a connecting hole is formed in one end, away from the first rubber sleeve, of the second rubber sleeve, and the connecting rod penetrates through the connecting hole and is in elastic contact with the inner wall of the connecting hole; the first rubber sleeve and the second rubber sleeve are made of elastic materials.

Preferably, a plurality of annular convex edges are arranged at intervals on the outer side of the first rubber sleeve, annular clamping grooves are formed in the inner side wall of the supporting sleeve, and the annular convex edges can be embedded in the annular clamping grooves; and a plurality of annular grooves are formed in the outer side wall of the second rubber sleeve at intervals along the axis direction.

Preferably, the flange plate comprises an upper sub plate and a lower sub plate, the upper sub plate and the support sleeve are integrally formed, and the lower sub plate is connected with the detection pipe; the upper separating disc is fixedly connected with the lower separating disc through bolts, and a tetrafluoro gasket and the pressure gauge diaphragm are arranged between the upper separating disc and the lower separating disc.

Preferably, a sealing gasket with an L-shaped section is arranged on the display opening and positioned on the outer side of the glass plate, one side of the sealing gasket is abutted against the outer side surface of the glass plate, and the other side of the sealing gasket is abutted against the side edge of the glass plate and is abutted against the watch case; one end of the watchcase, which is close to the display opening, is bent outwards to form a limiting ring, a sealing cover is arranged on the limiting ring, and the glass plate and the sealing washer are positioned between the limiting ring and the sealing cover; the middle part of the sealing cover is hollow, and an elastic card bent towards the middle part is arranged on the side edge of the sealing cover; the elastic clamp can elastically abut against the limiting ring, and is positioned on one side surface of the limiting ring, which is far away from the glass plate.

Preferably, a diaphragm protection ring is arranged on the upper connecting column, the outer diameter of the diaphragm protection ring is larger than the inner diameter of the support sleeve, and a set distance exists between the diaphragm protection ring and the lower end of the support sleeve.

Preferably, a step is formed on the inner side of the support sleeve, the step divides the inner side of the support sleeve to form a first installation cavity and a second installation cavity, the first installation cavity is located at one end close to the watch case, the second installation cavity is located at one end close to the pressure gauge diaphragm, the diameter of the first installation cavity is larger than that of the second installation cavity, and the lower end of the sealing rubber plug abuts against the step in the initial position.

(III) advantageous effects

The invention provides a shock-proof diaphragm pressure gauge, which can provide shock-proof performance of the pressure gauge through shock-proof silicone oil added to the inner side of a shell, and meanwhile, can play a role in sealing through a sealing rubber plug arranged on the inner side of a supporting sleeve, so that the shock-proof silicone oil on the inner side of the shell is prevented from permeating into the pressure gauge diaphragm. This manometer measurable quantity low pressure medium guarantees measurement accuracy. Meanwhile, the sealing cover connected to the display opening is detachable, so that the watchcase is convenient to disassemble and assemble, and fatigue errors of the sensitive element and the movement part generated in long-term use can be automatically verified after the sealing cover is detached.

Drawings

FIG. 1 is a schematic semi-sectional view of a shock-resistant diaphragm pressure gauge according to the present invention;

FIG. 2 is a schematic view of a protruded sealing rubber plug in a shock-resistant diaphragm pressure gauge according to the present invention;

FIG. 3 is a schematic view of a protruding case of a shock-resistant diaphragm pressure gauge according to the present invention.

In the drawings, the reference numbers:

100. a watch case; 110. a display port; 111. a sealing gasket; 112. a limiting ring;

120. a glass plate; 130. mounting a plate; 140. a movement component; 150. a pressure display panel; 160. a pointer; 170. a connecting rod; 180. sealing the cover; 181. an elastic card;

200. a support sleeve; 210. an annular neck; 220. a step; 230. a first mounting cavity; 240. a second mounting cavity;

300. a flange plate; 310. distributing the plates upwards; 320. a lower sub-disc; 330. a tetrafluoro spacer;

400. a detection tube;

500. a pressure gauge diaphragm; 510. an upper connecting column; 511. a diaphragm protection ring;

600. connecting rod pieces; 610. a threaded rod; 620. connecting a sleeve; 621. a first tube section; 622. a second tube section; 622a, locking hole; 623. a locking screw;

700. sealing the rubber plug; 710. a first rubber sleeve; 711. an annular rib; 720. a second rubber sleeve; 721. connecting holes; 722. an annular groove.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Examples

The invention provides an earthquake-proof diaphragm pressure gauge, which is shown in figures 1-3 and comprises a shell 100, wherein a display opening 110 is formed in one side of the shell 100, and a transparent glass plate 120 is hermetically arranged at the display opening 110; a mounting plate 130 is detachably attached to the case 100 on the side away from the glass plate 120, and a core member 140, a pressure display plate 150 and a pointer 160 are provided on the mounting plate 130. A support sleeve 200 is integrally formed on the watch case 100, the lower end of the support sleeve 200 is connected with a flange plate 300, and the lower end of the flange plate 300 is provided with a detection tube 400; a pressure gauge diaphragm 500 is arranged on the inner side of the flange plate 300; the detection tube 400 is communicated with the lower end of the pressure gauge diaphragm 500; an upper connection column 510 is arranged on the upper side of the pressure gauge diaphragm 500, a connection rod member 600 is arranged on the inner side of the support sleeve 200, and two ends of the connection rod member 600 are respectively connected with the upper connection column 510 at the lower end and the movement part 140 at the upper end; when detecting pressure, the detecting tube 400 is located inside the tube 400 to be detected, and the difference between the pressure in the tube 400 to be detected and the atmospheric pressure will drive the pressure gauge diaphragm 500 to recess upwards or downwards, in this process, the connecting rod 600 will be driven to displace, the connecting rod 600 will drive the movement part 140 to move, and then the pointer 160 will be controlled to display the pressure value. It should be noted that the movement component 140 is a conventional pressure meter movement component 140, and will not be described herein.

The inner side of the watch case 100 is filled with shock-proof silicon oil, and a sealing rubber plug 700 is arranged in the support sleeve 200. Through the sealed plug 700 that sets up with shock-resistant silica gel seal in watchcase 100 inboardly to a certain extent, realize the shock attenuation effect through shock-resistant silicone oil to a certain extent, simultaneously, can ensure that silicone oil can not permeate on the manometer diaphragm 500.

Wherein the connection rod 600 includes a threaded rod 610 and a connection sleeve 620; the connection sleeve 620 comprises a first pipe segment 621 and a second pipe segment 622, the first pipe segment 621 and the second pipe segment 622 are integrally formed, and the first pipe segment 621 is located at the lower side of the sealing rubber plug 700; the second tube 622 is located inside the sealing plug 700. The upper end of the threaded rod 610 is in threaded connection with the first pipe segment 621; the lower end of the movement part 140 is connected with a connecting rod 170, and the connecting rod 170 passes through the sealing rubber plug 700 and is detachably connected with a second pipe section 622. Specifically, a locking hole 622a is formed in the side wall of the second pipe segment 622, a locking screw 623 is threadedly connected to the locking hole 622a, and one end of the locking screw 623 penetrates through the locking hole 622a and abuts against the connecting rod 170 inside the second pipe segment 622. During operation, verification is performed by adjusting the positions of the connecting rod 170 and the locking screw 623 after detachment. Avoid the fatigue error of the sensitive element and the core transmission mechanism generated during long-time use.

The sealing rubber plug 700 comprises a first rubber sleeve 710 and a second rubber sleeve 720 which are positioned on the inner side of the support sleeve 200, the first rubber sleeve 710 and the second rubber sleeve 720 are integrally formed, and the outer diameter of the first rubber sleeve 710 is larger than that of the second rubber sleeve 720; the first rubber sleeve 710 is detachably connected with the support sleeve 200 in a sealing manner, one end of the second rubber sleeve 720, which is far away from the first rubber sleeve 710, is provided with a connecting hole 721, and the connecting rod 170 penetrates through the connecting hole 721 and is in elastic contact with the inner wall of the connecting hole 721; the first rubber cover 710 and the second rubber cover 720 are made of elastic materials.

A plurality of annular convex ridges 711 are arranged at intervals on the outer side of the first rubber sleeve 710, an annular clamping groove 210 is formed in the inner side wall of the support sleeve 200, and the annular convex ridges 711 can be embedded in the annular clamping groove 210; the annular convex rib 711 and the annular groove 210 can be mutually embedded and sealed, so that the first rubber sleeve 710 and the support sleeve 200 are connected in a sealing manner.

The outer side wall of the second rubber sleeve 720 is provided with a plurality of annular grooves 722 at intervals along the axial direction. When the pressure gauge is in operation, after the pressure gauge diaphragm 500 deforms due to an external force, the connecting rod 600 can move in the vertical direction, and in the moving process, the connecting rod and the sealing rubber plug 700 can slide relatively, or the second rubber sleeve 720 is driven to deform in the vertical direction, and the precision value of the pressure gauge is not affected in the process. In a more preferred manner, the second rubber sleeve 720 may be in the form of a pleat.

The flange plate 300 comprises an upper plate 310 and a lower plate 320, the upper plate 310 and the support sleeve 200 are integrally formed, and the lower plate 320 is connected with the detection tube 400; the upper minute plate 310 and the lower minute plate 320 are fixedly connected through bolts, and a tetrafluoro gasket 330 and a pressure gauge diaphragm 500 are arranged between the upper minute plate 310 and the lower minute plate 320. Wherein the upper connection column 510 passes through the tetrafluoro spacer 330.

A seal gasket 111 having an L-shaped cross section is provided on the display opening 110 and located outside the glass plate 120, and one side of the seal gasket 111 abuts against the outer side surface of the glass plate 120 and the other side abuts against the side of the glass plate 120 and abuts against the wristwatch case 100. The watch case 100 is bent outward at an end near the display opening 110 to form a limit ring 112, a cover 180 is disposed on the limit ring 112, and the glass plate 120 and the sealing gasket 111 are disposed between the limit ring 112 and the cover 180.

The middle of the cover 180 is hollow, and the hollow area is covered by the glass plate 120, so that the rotating position of the pointer 160 can be observed conveniently, and data can be read. An elastic clip 181 bent toward the middle is disposed on the side of the sealing cover 180; the elastic clip 181 can elastically abut against the position-limiting ring 112, and the elastic clip 181 is located on a side surface of the position-limiting ring 112 away from the glass plate 120. After the installation, the glass plate 120 is covered by the cover 180, and the sealing gasket 111 and the glass plate 120 are pressed tightly by the position matching of the elastic clamp 181 and the limiting ring 112, so that the sealing effect is realized.

The upper connection column 510 is provided with a diaphragm protection ring 511, the outer diameter of the diaphragm protection ring 511 is larger than the inner diameter of the support sleeve 200, and a set distance exists between the diaphragm protection ring 511 and the lower end of the support sleeve 200. The pressure gauge diaphragm 500 can be protected by the diaphragm protection ring 511, and when the pressure value to be detected is too large, the diaphragm protection ring 511 is abutted against the support sleeve 200 on the upper side, so that the pressure gauge diaphragm 500 can be protected to a certain extent.

Step 220 is formed on the inner side of the support sleeve 200, the step 220 divides the inner side of the support sleeve 200 into a first installation cavity 230 and a second installation cavity 240, the first installation cavity 230 is located at one end close to the watch case 100, the second installation cavity 240 is located at one end close to the pressure gauge diaphragm 500, the diameter of the first installation cavity 230 is larger than that of the second installation cavity 240, and the lower end of the sealing rubber plug 700 abuts against the step 220 at the initial position. Through the step 220 that sets up, can support sealed plug 700, play the resistance to compression effect to a certain extent, improve the sealed effect between sealed plug 700 and the support sleeve 200.

The invention provides a shock-proof diaphragm pressure gauge, when in use, a flange plate 300 is fixed on a pipe 400 to be detected, and a detection pipe 400 is inserted into the inner side of the pipe 400 to be detected for pressure detection. In the detection process, as the shock-proof silicone oil is added to the inner side of the watchcase 100, the shock-proof performance of the pressure gauge can be provided to a certain extent in the detection process.

The invention provides a shock-proof diaphragm pressure gauge, which can provide shock-proof performance of the pressure gauge through shock-proof silicone oil added to the inner side of a watch case 100, and meanwhile, can play a role of sealing through a sealing rubber plug arranged at the inner side of a supporting sleeve 200, so as to prevent the shock-proof silicone oil at the inner side of the watch case 100 from permeating into a pressure gauge diaphragm 500. This manometer measurable quantity low pressure medium guarantees measurement accuracy. Meanwhile, the cover 180 detachably connected to the display opening 110 facilitates the assembly and disassembly of the watch case 100, and fatigue errors of the sensitive element and the movement part 140 generated during long-term use can be automatically verified after the cover 180 is detached.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "rear", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly and may include, for example, a fixed connection, a detachable connection, an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, and a communication between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art. The embodiments and features of the embodiments of the present invention may be combined with each other without conflict.

The above-mentioned embodiments only express the embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. An earthquake-resistant diaphragm pressure gauge comprises a gauge shell (100), wherein a display port (110) is formed in one side of the gauge shell (100), and a light-transmitting glass plate (120) is arranged at the display port (110); a mounting plate (130) is detachably connected to a side of the case (100) away from the glass plate (120), and a movement part (140), a pressure display plate (150) and a pointer (160) are provided on the mounting plate (130), characterized in that: a support sleeve (200) is integrally formed on the watch case (100), a flange plate (300) is connected to the lower end of the support sleeve (200), and a detection pipe (400) is arranged at the lower end of the flange plate (300); a pressure gauge diaphragm (500) is arranged on the inner side of the flange plate (300); the detection tube (400) is communicated with the lower end of the pressure gauge diaphragm (500);

an upper connecting column (510) is arranged on the upper side of the pressure gauge diaphragm (500), a connecting rod piece (600) is arranged on the inner side of the supporting sleeve (200), and two ends of the connecting rod piece (600) are respectively connected with the upper connecting column (510) and the movement component (140);

the inner side of the watchcase (100) is filled with shock-proof silicone oil, and a sealing rubber plug (700) is arranged in the support sleeve (200).

2. The rugged diaphragm pressure gauge of claim 1, wherein: the connecting rod (600) comprises a threaded rod (610) and a connecting sleeve (620);

the connecting sleeve (620) comprises a first pipe section (621) and a second pipe section (622), the first pipe section (621) and the second pipe section (622) are integrally formed, and the first pipe section (621) is positioned at the lower side of the sealing rubber plug (700);

the upper end of the threaded rod (610) is in threaded connection with the first pipe section (621);

the lower end of the movement component (140) is connected with a connecting rod (170), and the connecting rod (170) penetrates through the sealing rubber plug (700) and is detachably connected with the second pipe section (622).

3. The rugged diaphragm pressure gauge of claim 1, wherein: a locking hole (622 a) is formed in the side wall of the second pipe section (622), a locking screw (623) is connected to the locking hole (622 a) in a threaded mode, one end of the locking screw (623) penetrates through the locking hole (622 a), and the connecting rod (170) on the inner side of the second pipe section (622) is abutted tightly.

4. The rugged diaphragm pressure gauge of claim 1, wherein: the sealing rubber plug (700) comprises a first rubber sleeve (710) and a second rubber sleeve (720) which are positioned on the inner side of the supporting sleeve (200), the first rubber sleeve (710) and the second rubber sleeve (720) are integrally formed, and the outer diameter of the first rubber sleeve (710) is larger than that of the second rubber sleeve (720);

the first rubber sleeve (710) is detachably connected with the support sleeve (200) in a sealing mode, one end, far away from the first rubber sleeve (710), of the second rubber sleeve (720) is provided with a connecting hole (721), and the connecting rod (170) penetrates through the connecting hole (721) and is in elastic contact with the inner wall of the connecting hole (721); the first rubber sleeve (710) and the second rubber sleeve (720) are made of elastic materials.

5. The rugged diaphragm pressure gauge of claim 1, wherein: a plurality of annular convex ribs (711) are arranged at intervals on the outer side of the first rubber sleeve (710), an annular clamping groove (210) is formed in the inner side wall of the supporting sleeve (200), and the annular convex ribs (711) can be embedded in the annular clamping groove (210);

the outer side wall of the second rubber sleeve (720) is provided with a plurality of annular grooves (722) at intervals along the axial direction.

6. The rugged diaphragm pressure gauge of claim 1, wherein: the flange plate (300) comprises an upper sub plate (310) and a lower sub plate (320), the upper sub plate (310) and the support sleeve (200) are integrally formed, and the lower sub plate (320) is connected with the detection pipe (400);

go up minute dish (310) with divide dish (320) down through bolt fixed connection, go up and be provided with tetrafluoro gasket (330) between minute dish (310) and the lower minute dish (320) and manometer diaphragm (500).

7. The rugged diaphragm pressure gauge of claim 1, wherein: a sealing gasket (111) with an L-shaped section is arranged on the display opening (110) and positioned on the outer side of the glass plate (120), one side of the sealing gasket (111) is abutted against the outer side surface of the glass plate (120), and the other side of the sealing gasket is abutted against the side edge of the glass plate (120) and is abutted against the watch case (100);

one end of the watchcase (100) close to the display opening (110) is bent outwards to form a limiting ring (112), a sealing cover (180) is arranged on the limiting ring (112), and the glass plate (120) and the sealing washer (111) are positioned between the limiting ring (112) and the sealing cover (180);

the middle part of the sealing cover (180) is hollow, and an elastic card (181) bent towards the middle part is arranged on the side edge of the sealing cover; the elastic clamp (181) can be elastically abutted against the limiting ring (112), and the elastic clamp (181) is positioned on one side surface of the limiting ring (112) far away from the glass plate (120).

8. The rugged diaphragm pressure gauge of claim 1, wherein: the diaphragm protection ring (511) is arranged on the upper connecting column (510), the outer diameter of the diaphragm protection ring (511) is larger than the inner diameter of the supporting sleeve (200), and a set distance exists between the diaphragm protection ring (511) and the lower end of the supporting sleeve (200).

9. The rugged diaphragm pressure gauge of claim 1, wherein: the inner side of the support sleeve (200) is provided with a step (220), the step (220) divides the inner side of the support sleeve (200) to form a first installation cavity (230) and a second installation cavity (240), the first installation cavity (230) is located at one end close to the watchcase (100), the second installation cavity (240) is located at one end close to the pressure gauge diaphragm (500), the diameter of the first installation cavity (230) is larger than that of the second installation cavity (240), and in an initial position, the lower end of the sealing rubber plug (700) abuts against the step (220).