JP2008051716A - Flow meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow meter for reducing the pressure difference between an internal pressure and an external pressure within a box maintained while the box for accommodating a flow rate indicating mechanism is maintained surely and airtightly, changing airtight state within the box in two steps at a fixed level or higher, and stably maintaining the airtight state at the fixed level or higher for a long time. <P>SOLUTION: In the flow meter, the box 5 is pressed against and held by fixing an upper case 1 and a lower case 7, in a state where a transparent shielding member 3 is assembled by an assembly member 2 via a sealing ring 4. If the assembly member 2 is fitted to the box 5 and rotated about the central axis line O, engagement sections 23, 55 are engaged with and fixed to each other, the sealing ring 4 are compressed, and the interior of the box 5 goes into an airtight state. The sealing ring 4 is additionally compressed by fixing the upper case 1 and the lower case 7, and the interior of the box 5 goes into a high airtight state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flow meter such as a water meter.

JP-A-8-43153

  As shown in FIG. 9, the conventional flow meter accommodates a flow rate indicating mechanism 6 inside a box unit 5 and covers the flow rate indicating surface side of the flow rate indicating mechanism 6 with glass 3. In this state, the box unit In many cases, the upper case (not shown) and the lower case (not shown) are screwed together so that the glass 5 and the glass 3 are positioned or narrowed so that they are positioned. In this case, since the flow rate indication value by the flow rate indication mechanism 6 must be clearly readable through the glass 3 fixed to the box portion 5, the inner surface of the glass 3 is clouded due to the difference between the internal temperature of the box portion 5 and the outside air temperature. Therefore, it is necessary to keep the inside of the box part 5 in a dehumidified state. For this reason, in the conventional flowmeter, the method of fixing the glass 3 by lowering the internal pressure of the box part 5 from the external pressure at the time of assembly, or a sealing member as shown in Patent Document 1 (reference numeral 4 in FIG. 9). Many of the methods using this method have been adopted.

  However, when the airtightness is measured by the method of fixing by the pressure difference between the internal pressure and the external pressure, the internal / external pressure difference is large despite the purpose of airtightness, so that an action of sucking in an external gas or liquid occurs. For this reason, even if the humidity in the box was kept small at the initial stage of assembly, the inner surface of the glass may become cloudy in the future.

  In the case of the method using the seal member as shown in Patent Document 1, the seal member is compressed by fixing the upper case and the lower case so that the inside of the box portion is airtight, and the flow meter is completed. However, once the flowmeter is made airtight at the stage of manufacturing the flowmeter, if it is necessary to adjust the flow measurement part by a later measurement inspection, the upper case is removed to take out the flow measurement part. Hermeticity is broken. At this time, since the seal member has already been compressed for a certain period at a level at which the inside of the box portion can be kept airtight for a long period of time, there is a possibility that the seal member is plastically deformed. The required airtight level may not be achieved. If the seal member is replaced at this time, a problem remains in cost.

  As another method for fixing the glass, an annular glass pressing member having an L-shaped cross section is used, and the box portion is locked together with the covered glass by a snap fit provided on the glass pressing member. There is also a method of sandwiching and fixing glass to the box part. In this case, since the glass pressing member is locked to the box portion by the snap fit portion having a relatively small rigidity that is allowed to be elastically deformed, there is a problem in strength in consideration of long-term locking and holding.

  The present invention has been made in view of the above-described problems, and while reducing the pressure difference between the internal pressure and the external pressure inside the box portion while securely holding the inside of the box portion that houses the flow rate indicating mechanism, the inside of the box is reduced. An object of the present invention is to provide a flow meter that can change the hermetic state to two stages above a certain level and can stably maintain the airtight state above the certain level over a long period of time.

Means and actions / effects for solving the problems

In order to solve the above problems, the flowmeter of the present invention is:
It has a cylindrical shape with an open upper surface, and at least the opening-side end portion is a cylindrical opening shielding assembly portion, and the see-through blocking member receiving portion extends along the circumferential direction of the inner peripheral surface of the opening shielding assembly portion. Is formed, and a box portion that houses the flow rate instruction mechanism so that the flow rate instruction value can be visually recognized from the opening inside itself,
A fluoroscopic shielding member configured to shield the opening of the box portion in a form in which the outer peripheral edge of the fluoroscopic shielding member receiving unit is supported from the lower side and the flow rate instruction value of the flow rate instruction mechanism can be seen through;
The outer peripheral edge of the holding part is inserted into the gap between the ring-like pressing part arranged on the outer peripheral part of the upper surface of the fluoroscopic shielding member and the inner peripheral surface of the opening shielding assembly part and the outer peripheral surface of the transparent shielding member. An assembly member integrated with a cylindrical fixing portion extending downward from
An elastic seal ring disposed between the fluoroscopic shielding member and the fluoroscopic shielding member receiving portion along the outer peripheral edge of the fluoroscopic shielding member;
A plurality of box-side engagement portions formed at predetermined intervals in the circumferential direction so as to protrude inward on the inner peripheral surface of the opening shielding assembly portion, and an assembly member corresponding to each box-side engagement portion A plurality of assembly member side engagement portions formed at predetermined intervals in the circumferential direction so as to protrude outward from the outer peripheral surface of the cylindrical fixing portion, and in the central axis direction of the cylindrical opening shielding assembly portion Each of the assembly member side engaging portions is positioned at a first position that is above the lower surface of the box side engaging portion corresponding to the upper surface of each of the assembled member side engaging portions when the elastic seal ring is not compressed and deformed. In the state of being compressed and deformed by a certain amount or more in the central axis direction, each forming position is determined so as to be positioned at the second position which is below, and each assembly member side engaging portion is arranged between the adjacent box side engaging portions. Insert the assembly member into the gap in the direction inside the opening shield assembly The assembly member is mounted while the elastic seal ring is compressed and deformed with the relative angular position of the assembly member corresponding to the attachment position relative to the box portion as the rotation start angle position, and the upper surface of the corresponding assembly member side engagement portion. And a bayonet mechanism for securing the assembly member to the box portion by attaching and rotating it around the central axis until the rotation completion angle position where the lower surface of the box side engagement portion engages,
It is provided with.

  According to the configuration of the present invention, the opening side of the box portion that accommodates the flow rate display mechanism is covered with the transparent shielding member (for example, glass) via the elastic seal ring (for example, rubber packing), and presses the transparent shielding member. The assembly member is arranged in the form. And the box part and the assembly | attachment member are fixed by the bayonet mechanism which has the said structure, and the inside of a box part is airtight. As a result, the pressure difference between the inside of the box and the external pressure is small compared to a conventional flow meter that intentionally reduces the internal pressure in the box and fixes the fluoroscopic shielding member as in the prior art, so it is difficult to suck liquid or gas from the outside. Become.

  Moreover, in the flowmeter of the said invention, in the form adjacent to the rotational movement direction of the assembly member side engaging part by assembly rotation operation with respect to each box side engaging part in the internal peripheral surface of an opening shielding assembly part. In addition, it is possible to provide an engaging portion stopper that prevents the corresponding assembly member side engaging portion from passing through the box side engaging portion and rotating. According to this configuration, it is possible to prevent the assembly member side engagement portion from rotating through the box side engagement portion during the assembly rotation operation, so that unnecessary rotation does not occur. Can do. Further, the assembly member 2 that is subjected to the assembly rotation operation can be reliably stopped at the engagement position between the assembly member side engagement portion and the box side engagement portion.

  In the flowmeter of the present invention described above, the engaging portion insertion groove for inserting the assembly member in the rotation axis direction with the assembly member positioned at the rotation start angle position is formed on the outer peripheral surface of the cylindrical fixing portion of the assembly member. The outer peripheral surface of the cylindrical fixing portion of the assembly member is formed in such a manner that the radial direction of the cylindrical fixing portion is the groove depth direction and the insertion port of the box side engaging portion is opened on the lower surface of the cylindrical fixing portion. Is formed with an engaging portion accommodating notch for accommodating the box side engaging portion in a state where the assembly member is positioned at the rotation completion angle position, and the engaging portion accommodating notch is a cylindrical fixing portion. One end of the cylindrical fixing portion in the circumferential direction communicates with the engaging portion insertion groove, and the other end reaches the adjacent engaging portion insertion groove, with the radial direction of the tube being the notch depth direction and the rotation axis direction being the notch width direction. Along the middle in the circumferential direction, a lower inner surface is formed at an intermediate position in the notch width direction, The portion forming the lower inner side surface of the joint housing notch portion forms the assembly member side engaging portion, and the portion forming the inner surface forming the other end of the engaging portion housing notch portion is formed as the engaging portion stopper. Can do.

  According to the configuration of the present invention, the assembly member is fixed to the box portion as follows. First, the assembly member is aligned with the box portion so that each engagement portion insertion groove of the assembly member is inserted into each box side engagement portion, and then the assembly member is fitted to the box portion. . Then, when the fixed amount is fitted (attachment position), the assembly member can be rotated in the assembly operation direction, so that the assembly member is rotated in that direction. Thereby, the assembly member side engaging part and the box side engaging part are engaged, and the assembly member is fixed to the box part. That is, the fixing of the assembly member and the box portion can be easily performed only by performing a fitting / rotating operation on the assembly member. In addition, the assembly member side engagement portion that supports the box side engagement portion is not formed assuming elastic deformation like the snap fit portion, so that the rigidity thereof can be relatively large. Therefore, it is excellent in strength and can keep a hermetic state at a certain level or more stably over a long period of time.

  In the case of this configuration, it may be formed such that the upper surface side of the engaging portion accommodation notch portion opens to the upper surface of the cylindrical fixing portion. If the assembly member is formed by, for example, injection molding of resin or the like, the mold used can be structured so that it can be easily removed from the molded assembly member.

  In the case of this configuration, on the side that communicates with the engaging portion insertion groove, the engagement is performed at the ridge line position where the end portion of the lower inner surface of the engaging portion receiving notch and the inner surface of the engaging portion insertion groove intersect. It is possible to form a chamfered portion that guides the box-side engaging portion from climbing from the portion insertion groove side onto the engaging portion stopper. According to this configuration, the ride-up movement from the engaging portion insertion groove to the engaging portion accommodating notch becomes easy.

  By the way, in the flowmeter of the present invention, in the bayonet mechanism, the reverse rotation preventing portion that prevents the assembly member side engagement portion of the assembly member from returning from the rotation completion angle position to the rotation start angle position due to the reverse rotation of the assembly member. It can have. If the elastic seal ring is crushed so that the inside of the box is sealed at a certain level of hermeticity, then after the assembly member is removed and the hermetic state is broken, the crushing allowance of the elastic seal ring returns to the state before the hermeticity. Not necessarily. In particular, if the sealing is performed at a finished product level capable of maintaining airtightness for a long time, the possibility that the elastic seal ring returns to the state before airtightness is low. Therefore, it is difficult to maintain the previous airtight level even if the assembly member is assembled again using the seal ring once used. According to the said structure, it can prevent that the assembly | attachment member once fixed by the reverse rotation prevention part falls off from a box part.

  In this case, the engagement portion insertion groove and the engagement portion accommodation notch portion are formed on the outer peripheral surface of the cylindrical fixing portion of the assembly member, and the box is formed in the engagement portion insertion groove. As the side engagement portion is inserted into the engagement portion insertion groove, the box side engagement portion is elastically deformed in the insertion direction while being in contact with the box side engagement portion, and the box side engagement portion is inserted into the engagement portion insertion groove. When the box side engaging portion reaches the second position, the engaging portion insertion groove of the box side engaging portion by the assembling rotation operation is allowed to move from the first position to the second position. The box-side engagement portion is engaged with the box-side engagement portion and is elastically restored as the box-side engagement portion moves into the engagement-portion-notch portion. An engagement part reverse movement prevention claw as a reverse rotation prevention part for preventing reverse movement to the joint insertion groove side should be provided. Can. According to this configuration, the engagement portion reverse movement preventing claw is provided, so that when the assembly member is assembled to the box portion, from the engagement portion insertion groove of the box side engagement portion to the engagement portion accommodation notch portion. The movement requires elastic deformation of the engaging portion reverse movement preventing claw, and the box side engaging portion moves from the engaging portion insertion groove to the engaging portion receiving notch portion and is assembled with the box side engaging portion. When the member side engaging portion is engaged, the assembly member and the box portion are fixed so as not to be easily detached. Prevents incorrect fixing due to the presence of an engaging part reverse movement prevention claw that prevents the fixing of the assembly member and the box part that cannot be removed once it is fixed or is extremely difficult to remove. Can do.

  The engaging portion reverse movement preventing claw is fixed to the inner surface on the opposite side to the engaging portion receiving notch portion of the engaging portion insertion groove, and the other end side is the engaging portion receiving notch. It is possible to extend in the circumferential direction of the cylindrical fixing portion toward the portion. According to this configuration, since the engaging portion reverse movement preventing claw has a shape extending in the circumferential direction of the cylindrical fixing portion, the engaging portion reverse movement preventing claw is further away from the claw proximal end side and becomes more elastic toward the claw distal end side. It becomes easy to deform. That is, the closer the engagement portion reverse movement prevention claw is to the engagement portion accommodation notch portion from the engagement portion insertion groove, the greater the amount of elastic deformation of the engagement portion reverse movement prevention claw becomes. Therefore, the movement from the engaging part insertion groove part of the box side engaging part to the engaging part accommodation notch part becomes easy.

  Further, in the central axis direction, the engaging portion reverse movement preventing claw has a lower surface formed with a gap smaller than the thickness of the box side engaging portion between the lower inner side surface of the engaging portion receiving notch portion. The box side engaging portion is elastically deformed upward by engaging the reverse movement preventing claw of the engaging portion to expand the gap while performing the assembling rotation operation. It is possible to pass through the expanded gap and be accommodated in the engaging portion accommodating notch. According to this configuration, since the engaging portion reverse movement preventing claw is formed so that a gap is formed from the engaging portion insertion groove portion toward the engaging portion receiving notch portion, the engaging portion of the box side engaging portion The movement from the insertion groove portion to the engaging portion accommodation notch portion is enabled by slight elastic deformation of the engaging portion reverse movement preventing claw. Further, the engagement portion of the box-side engagement portion is formed by continuously reducing the thickness of the engagement portion reverse movement preventing claw in the central axis direction from the nail proximal side to the claw tip side. Movement from the insertion groove portion to the engaging portion accommodating notch portion can be facilitated.

  Moreover, the front end surface of the engaging portion reverse movement preventing claw can be a cut surface along the central axis direction. According to this configuration, when the box side engaging portion is in the engaged state with the assembling member side engaging portion in the engaging portion accommodating notch, the assembling member is operated in the reverse rotation to the assembling rotation operation. Even so, the movement of the box side engaging portion is prevented by the leading end of the engaging portion reverse movement preventing claw. For this reason, it is possible to effectively prevent the assembled member once fixed from falling off the box portion.

  In the flowmeter of the present invention, a jig engaging portion for engaging a jig for assembling rotation operation can be formed on the inner peripheral surface of the pressing portion of the assembling member. Furthermore, the jig engaging portion can be a plurality of concave portions formed at predetermined intervals in the circumferential direction of the assembly member. Since the assembly member is arranged on the inner peripheral side of the opening of the box portion, the assembly rotation operation cannot be easily performed. However, if the jig can be used, the assembly member can be easily rotated.

  In addition, the flowmeter of the present invention exposes the upper surface side of the box portion assembled with the see-through shielding member interposed with the elastic seal ring by the assembly member at its upper surface side opening, A cylindrical upper case in which case holding ribs that hold the outer peripheral edge of the upper surface of the box portion along the periphery of the opening extend radially inward and attach to and detach from the upper case at the lower end of the upper case The outer case is fixed between the lower case and the upper case and the lower case. The outer elastic member is compressed and deformed in the direction of the central axis in a fixed state between the upper case and the lower case. And a bayonet mechanism that is assembled and rotated to a rotation completion angle position to engage the assembly member side engagement portion with the box side engagement portion while compressively deforming the elastic seal ring. In the loose seal fixing state in which the inside of the box portion is sealed by the elastic seal ring, the upper case is placed on the box portion in the loose seal fixing state, and the upper peripheral edge of the box portion is the upper case case. The upper case is centered on the assembly member while the upper case 1 and the lower case 7 are fixed and the outer elastic seal member is compressed and deformed in the direction of the central axis while being arranged to be held by the holding rib. By pressing downward in the axial direction and further compressing and deforming the elastic seal ring that has already been compressed in the loose seal fixed state in the central axial direction, the inside of the box portion is more elastic than in the loose seal fixed state. The main seal can be fixed with a large amount of compression.

  According to this configuration, the hermetic level in the box portion can be adjusted in two steps between the loose seal fixed state and the main seal fixed state. Accordingly, the fluoroscopic shielding member and the elastic seal ring can be temporarily fixed (loose seal fixed state) to the box portion that houses the flow rate instruction mechanism by the assembly member, and the flow meter can be easily assembled. In addition, even if the upper case is removed from the main seal fixing state and returned to the loose fixing state with respect to the flowmeter of the present invention, the compression of the elastic seal member remains up to the compression level of the loose seal fixing state, The state can be kept above a certain level. In this case, the close contact state between the fluoroscopic shielding member and the box portion does not change greatly even when the loosely fixed state is restored. Therefore, even if the upper case is fixed again from this state and the main seal is fixed, This airtight state can be maintained at the same level as that of the main seal fixing state.

  Moreover, the flowmeter of this invention can set the internal diameter of the opening part of an upper case larger than the internal diameter of an assembly | attachment member. By providing the assembly member, the distance from the flow rate indicating surface of the flow rate display mechanism to the upper surface of the upper case is increased, and there is a possibility that the pointer or the indicated value is far or small. According to the above configuration, the inner diameter of the assembly member is made smaller than that of the upper case to form a step, so that the sense of distance to the flow rate indicating surface can be reduced, and the pointer and the indicated value can be easily read.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an embodiment of a flow meter of the present invention. A flow meter 100 in FIG. 1 includes a box unit 5 that houses a flow rate instruction mechanism 6 therein, a fluoroscopic shielding member 3 in which a flow rate instruction value of the flow rate instruction mechanism 6 can be seen through the box unit 5, and a fluoroscopic shield. An assembly member 2 for securing the member 3 to the box part 5 and a ring-shaped inner elastic sealing member (elastic) arranged between the see-through shielding member 3 and the box part 5 to seal the inside of the box part 5 Seal ring) 4, a bayonet mechanism 25 that fixes the assembly member 2 and the box portion 5, and further includes an upper case 1, a lower case 7 containing the flow rate measuring portion 8, and a ring-shaped outer elastic seal. And a member (elastic seal ring) 40.

  As shown in FIG. 2, the box portion 5 has a cylindrical shape with an open upper surface, and at least an end portion on the opening 50 side is a cylindrical opening shielding assembly portion 51. A fluoroscopic shielding member receiving portion 52 for supporting the fluoroscopic shielding member 3 is formed along the circumferential direction of the inner peripheral surface of the portion 51. Further, the flow rate instruction mechanism 6 is accommodated inside, and the flow rate instruction value indicated by the flow rate instruction mechanism 6 can be visually confirmed from the opening 50.

  The flow rate display mechanism 6 utilizes the property that the rotational speed of the impeller 82 mechanically or electrically measured by the flow rate measuring unit 8 is proportional to the amount of water passing through the measuring chamber 81. And it is comprised by the well-known mechanism which displays the amount of water (volume flow volume).

  Further, the box portion 5 has an outer peripheral surface of the main body portion 53 below the opening shielding assembly portion 51 having a diameter smaller than that of the outer peripheral surface of the opening shielding assembly portion 51, and the main body portion 53 and the opening shielding assembly 51. A stepped surface 57 that absorbs the difference in diameter between the two outer peripheral surfaces is formed at a boundary position with the attaching portion 51. A plurality of box-side engaging portions 55 projecting inward are formed on the inner peripheral surface of the opening shielding assembly 51 at predetermined intervals in the circumferential direction of the inner peripheral surface.

  The fluoroscopic shielding member 3 is a transparent glass member in the present embodiment, and its outer peripheral edge is supported from below by the fluoroscopic shielding member receiving portion 52 of the box portion 5. Thereby, the opening 50 of the box portion 5 is shielded and the flow rate instruction value of the flow rate instruction mechanism 6 can be seen through.

  As shown in FIGS. 3 and 4, the assembling member 2 includes a pressing portion 2 a that presses the fluoroscopic shielding member 3 from the upper side in the central axis O direction, and a cylindrical fixing that covers the upper outer peripheral surface of the fluoroscopic shielding member 3 from the outside. The part 2b is integrated. The pressing portion 2a is formed in a ring shape and is disposed on the outer peripheral edge portion of the upper surface of the fluoroscopic shielding member 3, and prevents the fluoroscopic shielding member 3 from falling out by pressing it from above. The cylindrical fixing portion 2b is formed in a cylindrical shape so as to extend downward from the outer peripheral edge of the pressing portion 2a, and is inserted into a gap between the outer peripheral surface of the fluoroscopic shielding member 3 and the inner peripheral surface of the opening shielding assembly portion 51. Is done. In addition, the assembly member side engaging portion 23 protruding outward from the outer peripheral surface of the cylindrical fixing portion 2b so as to correspond to each box side engaging portion 55 has a predetermined interval in the circumferential direction of the outer peripheral surface. A plurality are formed.

  The inner elastic seal member 4 is a well-known O-ring in the present embodiment, and as shown in FIG. 1, the see-through shielding member 3 and the see-through shielding member of the box portion 5 along the outer peripheral edge of the see-through shielding member 3. It arrange | positions between the receiving parts 52.

  The bayonet mechanism 25 is mainly composed of a plurality of box side engaging portions 55 formed in the box portion 5 and a plurality of assembly member side engaging portions 23 formed on the assembly member 2. In each assembly member side engaging portion 23, the lower surface 55 c of the box side engaging portion 55 corresponding to each upper surface 23 c in the direction of the central axis O of the cylindrical opening shielding assembly portion 51 is the inner elastic seal member 4. When the inner elastic seal member 4 is compressed and deformed by a certain amount or more in the direction of the central axis O, the second position is lower. It is formed so as to be located at a position ((b) in FIG. 5). The assembly member 2 is mounted inside the opening shielding assembly portion 51 of the box portion 5 by inserting each assembly member side engagement portion 23 into a circumferential gap between adjacent box side engagement portions 55. The When the relative angular position of the assembly member 2 corresponding to the mounting position with respect to the box portion 5 is the rotation start angle position S, the assembly member 2 compresses the inner elastic seal member 4 from the rotation start angle position S. While being deformed, an assembly rotation operation is performed around the central axis O to a rotation completion angle position T where the upper surface 23c of the corresponding assembly member side engagement portion 23 and the lower surface 55c of the box side engagement portion 55 are engaged. As a result, it is fixed to the box portion 5 to prevent it from coming off.

  Hereinafter, the bayonet mechanism 25 will be described in more detail. In the bayonet mechanism 25 according to the present embodiment, when the assembly member 2 is mounted on the box portion 5, first, as shown in FIG. 5A, the box side engagement portion 55 is engaged with the assembly member 2. The assembly member is attached to the box portion so as to pass through the joint insertion groove 22. Then, after the mounting, the mounting member 2 is rotated from the rotation start angle position S to the rotation completion angle position T with the mounting position as the rotation start angle position S. Thereby, the box side engaging part 55 of the box part 5 moves from the engaging part insertion groove 22 to the engaging part accommodating notch part 24, and as shown in FIG. It is comprised so that the box side engaging part 55 corresponding to the part 23 may engage.

  The engaging portion insertion groove 22 is formed on the outer peripheral surface of the cylindrical fixing portion 2 b of the assembly member 2 so as to correspond to the box side engaging portion 55. The engaging portion insertion groove 22 is cylindrical so that the box side engaging portion 55 passes when the assembly member 2 is mounted on the box portion 5 in the rotation axis direction with the assembly member 2 positioned at the rotation start angle position S. The radial direction of the fixed portion 2b is formed as the groove depth direction. Further, the engaging portion insertion groove 22 is formed in a shape having an opening 20 on the lower surface of the cylindrical fixing portion 2 b, and the box side engaging portion 55 can be inserted from the opening 20.

  The engaging portion accommodating notch portion 24 is also formed on the outer peripheral surface of the cylindrical fixing portion 2b of the assembly member 2, and the radial direction of the cylindrical fixing portion 2b is the notch depth direction and the rotation axis direction is the notch width direction. The one end side in the circumferential direction of the cylindrical fixing portion 2b is formed so as to communicate with the engaging portion insertion groove 22. On the other hand, an inner side surface 24a that forms an engaging portion stopper is formed on the other end side in the circumferential direction of the cylindrical fixing portion 2b, and the engaging surface is located next to the other end side of the engaging portion accommodating notch 24. The notch is interrupted at a midway position in the circumferential direction reaching the joint insertion groove 22, and is not in communication with the engagement part insertion groove 22. The non-communication side inner peripheral surface 24a that forms the engagement portion stopper restricts the assembly member 2 from rotating beyond the rotation completion angle position T with respect to the box portion 5 during the assembly rotation operation. That is, the non-communication side inner peripheral surface 24a is connected to each box side engagement portion 55 on the inner peripheral surface of the opening shielding assembly portion 51 of the box portion 5 by the assembly member side engagement portion 23 by the assembly rotation operation. It functions as an engaging portion stopper that prevents the corresponding assembling member side engaging portion 23 from rotating through the box side engaging portion 55 in a form adjacent to the rotational movement direction. Note that the upper surface side of the engaging portion accommodating notch 24 is open to the upper surface of the assembly member 2.

  A lower inner side surface 23 c is formed on the lower side of the engaging portion accommodating notch 24. A portion forming the lower inner side surface 23 c forms an assembly member side engagement portion 23, and the lower inner side surface 23 c is a surface corresponding to the upper surface of the assembly member side engagement portion 23. The engaging part insertion groove 22 side of the assembly member side engaging part 23 is an inner side surface 23 a of the engaging part insertion groove 22. The inner side surface 23a rotates the assembly member 2 with respect to the box portion 5 in the same direction as the rotational movement direction by the assembly rotation operation when the box side engagement portion 55 is in the engagement portion insertion groove 22. It is regulated. Further, the inner side surface 23a has a box portion in the same direction as the rotational movement direction by the assembling rotation operation when the box side engagement portion 55 is in the engagement portion accommodating notch portion 24 (rotation completion angle position). The rotation of the assembly member 2 with respect to 5 is restricted in such a way as to abut against the inner peripheral surface of the engagement portion insertion groove 22 opposite to the engagement portion accommodation notch portion 24. That is, the inner side surface 23a is also rotated in the rotational movement direction of the assembly member side engagement portion 23 by the assembly rotation operation with respect to each box side engagement portion 55 on the inner peripheral surface of the opening shielding assembly portion 51 of the box portion 5. , The corresponding assembly member side engagement portion 23 functions as an engagement portion stopper that prevents the corresponding assembly member side engagement portion 23 from rotating through the box side engagement portion 55.

  Further, on the side of the engaging portion receiving notch 24 that communicates with the engaging portion insertion groove 22, the end of the lower inner side surface 23 c of the engaging portion receiving notch 24 and the inner side surface 23 a of the engaging portion insertion groove 22 are provided. A chamfered portion 23b is formed at the ridgeline position where the box-side engaging portion 55 is guided from the engaging portion insertion groove 22 side to the inner side surface 23a (engagement portion stopper).

  Further, in the bayonet mechanism 25, the assembly member side engaging portion 23 of the assembly member 2 is rotated at a rotation completion angle position T by the reverse rotation of the assembly member 2 (rotation in the direction opposite to the rotation accompanying the assembly rotation operation). A reverse rotation preventing portion 21 is formed to prevent the rotation from returning to the rotation start angle position S.

  The reverse rotation preventing portion 21 in the present embodiment is formed as an engaging portion reverse movement preventing claw. The engagement portion reverse movement preventing claw 21 has a proximal end fixed to an inner surface of the engagement portion insertion groove 22 opposite to the side where the engagement portion accommodating notch 24 communicates, and The tip end side on the opposite side is formed so as to extend in the circumferential direction of the cylindrical fixing portion 2 b toward the engaging portion accommodating notch portion 24. The engagement portion reverse movement preventing claw 21 is formed to be inclined downward from the claw proximal side toward the claw distal side in the direction of the central axis O, and the claw thickness in the direction of the central axis O is further increased from the claw proximal side. It is formed by continuously decreasing toward the tip end side of the nail, and the amount of elastic deformation is easily increased toward the tip end side of the nail. Further, the engaging portion reverse movement preventing claw 21 has a box between the lower surface 21b of the engaging portion reverse movement preventing claw 21 and the lower inner side surface 23c of the engaging portion accommodating cutout portion 24 in the central axis O direction. A gap 224 smaller than the thickness of the side engaging portion 55 is formed, and is provided to be positioned above the lower inner side surface 23c.

  As shown in FIG. 5B, the engaging portion reverse movement preventing claw 21 formed in this way is formed in the engaging portion insertion groove 22 by inserting the box side engaging portion 55 into the engaging portion insertion groove 22. The elastic member can be elastically deformed in the insertion direction while abutting on the box side engaging portion 55 as it is inserted into the box, and the box side engaging portion 55 moves from the first position to the second position in the engaging portion insertion groove 22. Is allowed. In addition, the clearance gap 224 expands by the elastic deformation of the engaging part reverse movement prevention nail | claw 21 at this time. In the state where the box side engaging portion 55 has reached the second position, the box side engaging portion 55 passes through the expanded gap 224 so as to pass from the engaging portion insertion groove 22 into the engaging portion receiving notch portion 24. Therefore, the assembly rotation operation to the assembly member 2 becomes possible. When the assembly rotation operation is performed and the box side engaging portion 55 reaches the engaging portion accommodating notch 24, the engaging portion reverse movement preventing claw 21 is as shown in FIG. The box-side engagement portion 55 is prevented from moving back from the engagement portion accommodating notch portion 24 toward the engagement portion insertion groove 22 at the return position. Since the distal end surface 21a of the engaging portion reverse movement preventing claw 21 is a cut surface along the direction of the central axis O, when the engaging portion reverse movement preventing claw 21 is elastically restored, the distal end surface 21a becomes the box side engaging portion 55. On the other hand, it faces the circumferential direction of the assembly member 2 and prevents return rotation to the engaging portion insertion groove 22 side.

  Further, when the bayonet mechanism 25 is assembled and rotated to the rotation completion angle position T, as shown in FIG. 5C, the assembling member side engaging portion 23 is deformed while compressively deforming the inner elastic seal member 4. Engage with the box side engaging portion 55. Thereby, the flow rate display part 10 which consists of the assembly | attachment member 2, the see-through | permeation shielding member 3, the inner side elastic sealing member 4, and the box part 5 is formed. At this time, the inside of the box portion 5 is sealed by compressive deformation of the inner elastic seal member 4 (see FIG. 6), but this sealed state can keep the inside of the box portion 5 airtight in the short term. This is a temporary seal fixed state (loose seal fixed state) in which the elastic seal ring is deformed to the extent. In the present embodiment, the amount of compression in the central axis O direction of the inner elastic seal member 4 in the loose seal fixed state is within 1 to 15% of the entire inner elastic seal member 4 in the non-compressed state. Is desirable. In this case, since the deformation amount of the inner elastic seal member 4 is small, the assembly of the assembly member 2 to the box portion 5 is facilitated.

  As shown in FIG. 1, the flow meter 100 according to the present embodiment has the flow rate display unit 10 in a state where the temporary seal is fixed disposed inside the cylindrical upper case 1 and the lower case, and the upper case 1 and the lower case. And the flowmeter display unit 10 at this time has a higher airtight level than the temporary seal fixed state. It becomes.

  The lower case 7 has an inlet 71 provided at one side end thereof, an outlet 72 provided at the other side end, and an intermediate portion between the inlet 71 and the outlet 72 on the upper surface side. It is formed in a cylindrical shape having a space (measuring chamber) 70 having an opening 76 on the surface. The flow rate measuring unit 8 has an upper opening with respect to the space (measuring chamber) 70 with the flow rate display unit 10 attached to the upper part and the rectifying part 73 for rectifying the flow of water flowing into the impeller chamber attached to the lower part. Fit from 76.

  The upper case 1 is formed in a cylindrical shape penetrating in the direction of the central axis O, and the opening shielding assembly portion of the box portion 5 of the flow rate display unit 10 with respect to the lower case 7 to which the flow rate display unit 10 and the rectifying unit 73 are attached. 51 is arranged so as to cover 51 from the outside, and the lower end portion of the inner peripheral surface of the upper case 1 is fixed to the upper end portion of the outer peripheral surface of the lower case 7. In the present embodiment, the upper case 1 is formed by screwing the female screw portion 12 formed at the lower end portion of the inner peripheral surface of the upper case 1 and the male screw portion 72 formed at the upper end surface of the outer peripheral surface of the lower case 7. The lower case 7 is removably assembled. At this time, the upper surface side of the box portion 5 of the flow rate display unit 10 is exposed at the opening 16 on the cylindrical upper surface side, and the case holding rib 11 is formed to extend radially inward along the periphery of the upper surface side opening 16. Thus, the outer peripheral edge of the upper surface of the box portion 5 of the flow rate display unit 10 is retained.

  In this embodiment, the upper case 1 and the lower case 7 are fixed by fitting the upper end portion of the outer peripheral surface of the lower case 7 to the lower end portion of the inner peripheral surface of the upper case 1 and the lower end portion of the inner peripheral surface of the upper case 1. The internal thread portion 12 formed on the upper case and the external thread portion 72 formed on the upper end surface of the outer peripheral surface of the lower case 7 are fixed by screwing together. However, a ring-shaped outer elastic sealing member 40 is interposed between the stepped surface 57 of the box portion 5 and the upper end surface 77 of the lower case 7. By fixing the upper case 1 and the lower case 7, the box portion 5 is supported on the upper end surface 77 of the lower case 7 via the ring-shaped outer elastic seal member 40 on the stepped surface 57 with confidence. The entire flow rate display unit 10 including the box unit 5 is in a state of being narrowed in the direction of the central axis O by the case as the upper case.

  When the upper case 1 and the lower case 7 are thus fixed, the flow rate display unit 10 is changed from the temporary seal fixed state to the main seal fixed state. In the fixed state of the seal, the upper case 1 and the lower case 7 compress and deform the outer elastic seal member 40 in the direction of the central axis O, while the upper case 1 moves the assembly member 2 of the flow rate display unit 10 downward in the direction of the central axis O. By pressing to the side, the inner elastic seal member 4 is also compressed and deformed in the same direction. That is, the inner elastic seal member 4 that has already been compressed and deformed in the direction of the central axis O in the temporary seal fixed state is further compressed and deformed in the same direction when the main seal is fixed.

  In the present embodiment, in the temporary seal fixing state, the assembling portion 2 and the box portion 5 are positioned such that the uppermost surface 26 of the assembling member 2 is higher than the uppermost surface 56 of the box portion 5 as shown in FIG. It is formed as follows. When the upper case 1 and the lower case 7 are assembled, the case holding rib 11 of the upper case 1 contacts the uppermost surface 26 of the assembling member 2 above the uppermost surface 56 of the box portion 5. And it is comprised so that this assembly member 2 may be pressed to the center axis O direction lower side. When the upper case 1 presses the assembly member 2 downward in the central axis O direction, the see-through shielding member 3, the inner elastic seal member 4, and the box portion 5 are pressed in the same direction. And the lower case 7 supports the pressed box part 5 via the outer elastic seal member 40. Therefore, both the inner elastic seal member 4 and the outer elastic seal member 40 interposed between the upper case 1 and the lower case 7 are compressed and deformed.

  However, since the inner elastic seal member 4 is already compressed and deformed in the temporary seal fixed state, the inner elastic seal member 4 is further compressed from the compressed state, and the compression amount is larger in the main seal fixed state than in the temporary seal fixed state. In the present invention, the compression amount in the direction of the central axis O of the inner elastic seal member 4 in the main seal fixed state is set to be within 20 to 25% of the entire inner elastic seal member 4 in the non-compressed state. As a result, the flow meter 100 changes from the temporary seal fixed state to the main seal fixed state, so that the airtight level inside the box portion 5 becomes higher. That is, the inside of the box part 5 can be kept airtight for a longer period.

  In order to set the compression amount of the outer elastic seal member 40 by the upper case 1 (and consequently the compression amount of the inner elastic seal member 4 by the upper case 1) to a predetermined amount or an amount within a predetermined range, An upper case movement restricting portion that restricts movement displacement of the upper case 1 in the direction of the central axis O can be provided. In this embodiment, when the upper case 1 is fixed to the lower case 7, the case holding rib 11 of the upper case 1 presses the uppermost surface of the assembly member 2 downward in the central axis O direction. The amount of movement in the direction is a position that contacts either one of the uppermost surface 56 of the box portion 5 and the assembly member receiving portion 54 formed along the circumferential direction of the inner peripheral surface of the opening shielding assembly portion 51 of the box portion 5. It is regulated by. That is, although the upper case 1 is screwed into the lower case 7 to gradually approach each other, when the case holding rib 11 of the upper case 1 comes into contact with the uppermost surface 56 of the box portion 5 or the assembly member receiving portion 54, No further screwing is possible at the contact position.

  Further, the inner diameter of the opening 50 portion of the upper case 1 is formed larger than the inner diameter of the assembly member 2. Since the assembly member 2 is provided in the flow meter 100 of the present invention, the distance from the flow rate indicating surface of the flow rate display mechanism 6 to the upper surface of the upper case 1 is increased, and the pointer and indicated value are far or small. Although there is a possibility of feeling, since the inner diameter of the assembly member 2 is smaller than that of the upper case 1 and the step is formed, the sense of distance to the flow rate indicating surface can be reduced. The inner diameter φB of the assembly member is 80% to 98%, more preferably 85% to 95% with respect to the inner diameter φA of the upper case, so that the effect of reducing the sense of distance to the flow rate indicating surface is good. Is obtained.

  Further, a jig engaging portion 29 for engaging a jig for assembling and rotating operation is formed on the inner peripheral surface of the pressing portion 2a of the assembling member 2. The jig engaging portion 29 in the present embodiment is a concave portion that is formed on the inner peripheral surface of the pressing portion 2 a of the assembly member 2 and is recessed outward in the radial direction, and is predetermined in the circumferential direction of the assembly member 2. A plurality are formed at intervals. In addition, not a recessed part but a convex part may be sufficient, and they may be mixed. Further, considering the rotation by the jig, the number of the jig engaging portions 29 is preferably about 2 to 5. In the present embodiment, four are formed at equal intervals.

  As mentioned above, although embodiment of the flowmeter of this invention was described, this invention is not limited to the said embodiment, A various deformation | transformation is possible in the range which does not deviate from the main point of this invention. Hereinafter, the modification is illustrated. In addition, in these modified examples, the same reference numerals as those in the above embodiment are given to those showing functions similar to those in the above embodiment.

  For example, the assembly member 2 can be shaped as shown in FIG. In this case, as shown in FIG. 7A, the assembly member side engagement portion 23 of the assembly member 2 is engaged with the inner surface 23a that forms an engagement portion stopper on the engagement portion insertion groove 22 side and the engagement portion. 7 is formed in a shape having a lower inner side surface 23c of the housing notch, and further, at the intermediate position from the inner side surface 23a to the inner side surface 23c, as shown in FIG. A guide portion 210 having a guide surface 23b that guides the ride-up movement from the rotation start angle position S to the rotation completion angle position T of the engagement portion 55 is formed. Further, on the inner surface 23c side of the guide portion 210, a reverse rotation prevention surface 210a having a reverse rotation prevention function of the reverse rotation prevention portion 21 (more specifically, the front end surface 21a of the reverse rotation prevention portion 21) in the above embodiment is formed. 7 (c), the reverse rotation of the box side engaging portion 55 that has reached the rotation completion angle position T is prevented.

  Further, the assembly member 2 can be shaped as shown in FIG. In this case, the jig engaging portion 29 in the above embodiment is a convex portion 290 that protrudes inward in the radial direction and is formed on the inner peripheral surface of the holding portion 2 a of the assembly member 2. A plurality are formed at predetermined intervals in the direction. The convex portion 290 is integrally formed such that the upper portion 290a and the lower portion 290b form a step in the direction of the central axis O. Specifically, the lower portion 290b is formed to have a longer width in the circumferential direction of the assembly member 2 than the upper portion 290a, and the steps are formed on both sides of the assembly member 2 in the circumferential direction. Thereby, engagement with a jig | tool is made better.

Sectional drawing in this seal | sticker fixed state of the flowmeter which is one Embodiment of this invention, and its partial enlarged view. The perspective view of a box part, and its partial enlarged view. The perspective view of an assembly member, and its partial enlarged view. The top view, side view, and sectional drawing of an assembly | attachment member. The figure explaining the engagement process of an assembly member side engaging part and a box side engaging part. Sectional drawing of the flow volume display part in a loose seal fixed state, and its partial enlarged view. The side view which shows the assembly | attachment member of the flowmeter which makes 2nd embodiment of this invention. The perspective view which shows the assembly member of the flowmeter which makes 3rd embodiment of this invention, and its partial enlarged view. Sectional drawing of the conventional flowmeter, and its partial enlarged view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Flowmeter 1 Upper case 11 Case holding rib 2 Assembly member 2a Pressing part 2b Cylindrical fixing part 20 Opening of engagement part insertion groove 21 Engagement part reverse movement prevention claw (reverse rotation prevention part)
21a End face of engagement part reverse movement preventing claw 22 Engagement part insertion groove 23 Assembly member side engagement part 23a Inner side surface of engagement part insertion groove (engagement part stopper)
23b Chamfered portion 23c Upper surface of assembly member side engaging portion (lower inner side surface of engaging portion accommodating notch)
24 engaging part accommodation notch part 24a non-communication side inner peripheral surface (engaging part stopper)
25 Bayonet mechanism 224 Clearance 29 Jig engagement part 3 Perspective shielding member 4 Inner elastic seal ring (elastic seal ring)
DESCRIPTION OF SYMBOLS 5 Box part 6 Flow instruction | indication mechanism 7 Lower case 8 Flow measurement part 10 Flow rate display part 40 Outer elastic sealing member 50 Opening 51 Opening shielding assembly part 52 Transparent shielding member receiving part 53 Main body part 54 Assembly member receiving part 55 Box side relation Joint portion 55c Lower surface of the box side engaging portion O Center axis S Rotation start angle position T Rotation completion angle position

Claims (12)

It has a cylindrical shape with an open upper surface, and at least the opening-side end portion is a cylindrical opening shielding assembly portion, and the see-through blocking member receiving portion extends along the circumferential direction of the inner peripheral surface of the opening shielding assembly portion. Is formed, and a box portion that houses the flow rate instruction mechanism so that the flow rate instruction value is visible from the opening inside itself,
The see-through shielding member configured to shield the opening of the box portion in such a manner that the outer peripheral edge portion of the see-through shielding member receiving portion is supported from the lower side and the flow rate indication value of the flow rate indication mechanism can be seen through. Members,
The holding member is inserted into a gap between a ring-shaped pressing member disposed on the outer peripheral edge of the upper surface of the fluoroscopic shielding member and an inner peripheral surface of the opening shielding assembly portion and an outer peripheral surface of the transparent shielding member. An assembly member integrated with a cylindrical fixing portion extending downward from the outer peripheral edge of
An elastic seal ring disposed between the fluoroscopic shielding member and the fluoroscopic shielding member receiving portion along an outer peripheral edge of the fluoroscopic shielding member;
A plurality of box-side engaging portions formed at predetermined intervals in the circumferential direction so as to protrude inward on the inner peripheral surface of the opening shielding assembly portion, and the assembly corresponding to each box-side engaging portion A plurality of assembly member side engagement portions formed at predetermined intervals in the circumferential direction so as to protrude outward from the outer peripheral surface of the cylindrical fixing portion of the member, and the cylindrical opening shielding assembly portion In the central axis direction, each assembly member side engaging portion is located at a first position that is above the lower surface of the box side engaging portion to which the upper surface corresponds in a state where the elastic seal ring is not compressed and deformed. In the state in which the elastic seal ring is compressed and deformed by a predetermined amount or more in the central axis direction, the respective formation positions are determined so as to be positioned at the second position which is below, and each assembly member side engaging portion is adjacent to the box. Inserted into the circumferential gap between the side engaging portions A mounting member is attached to the inside of the opening shielding assembly portion, and the elastic seal ring is compressed and deformed with a relative angular position of the assembly member corresponding to the attachment position with respect to the box portion as a rotation start angular position. By assembling and rotating the assembly member around the central axis to the rotation completion angle position where the upper surface of the corresponding engagement member side engagement portion and the lower surface of the box side engagement portion engage with each other, A bayonet mechanism for securing the assembly member to the box portion, and
A flow meter characterized by comprising:   Each of the box-side engaging portions is adjacent to the box-side engaging portion in a form adjacent to the rotational movement direction of the assembly-member-side engaging portion by the assembling rotation operation. The flowmeter according to claim 1, further comprising an engaging portion stopper that prevents the portion from rotating through the portion. On the outer peripheral surface of the cylindrical fixing portion of the assembly member, there is an engaging portion insertion groove for inserting the assembly member in the rotation axis direction with the assembly member positioned at the rotation start angle position. The radial direction of the cylindrical fixing part is the groove depth direction, and the insertion port of the box side engaging part is formed in a shape that opens on the lower surface of the cylindrical fixing part,
Similarly, on the outer peripheral surface of the cylindrical fixing portion of the assembly member, an engagement portion accommodating notch for accommodating the box side engagement portion in a state where the assembly member is positioned at the rotation completion angle position. The engaging portion accommodating cutout portion has a radial direction of the cylindrical fixing portion as a cutout depth direction, the rotation axis direction as a cutout width direction, and one end in the circumferential direction of the cylindrical fixing portion is The engagement portion insertion groove communicates, and the other end is interrupted at a midway position in the circumferential direction reaching the adjacent engagement portion insertion groove, and a lower inner side surface is formed at an intermediate position in the notch width direction. A portion forming the lower inner side surface of the housing notch portion forms the assembly member side engaging portion, and a portion forming the inner surface forming the other end of the engaging portion housing notch portion serves as the engaging portion stopper. The flow meter according to claim 2 formed.   The flow meter according to claim 3, wherein an upper surface side of the engagement portion housing notch is open to an upper surface of the cylindrical fixing portion.   On the side communicating with the engaging portion insertion groove, the engaging portion is inserted at a ridge line position where the end portion of the lower inner surface of the engaging portion receiving notch and the inner surface of the engaging portion insertion groove intersect. The flow meter according to claim 3 or 4, wherein a chamfered portion is formed to guide the box-side engaging portion from riding on the engaging portion stopper from the groove side.   In the bayonet mechanism, the assembly member side engagement portion of the assembly member has a reverse rotation prevention portion that prevents the rotation completion angle position from returning to the rotation start angle position due to the reverse rotation of the assembly member. The flow meter according to any one of claims 1 to 5. Comprising the requirements of claim 3;
In the engagement portion insertion groove, as the box side engagement portion is inserted into the engagement portion insertion groove, the box side engagement portion is elastically deformed in the insertion direction while being in contact with the box side engagement portion. In a state in which the joint portion allows the movement from the first position to the second position in the engagement portion insertion groove and the box side engagement portion reaches the second position, The engagement portion accommodation notch of the box side engagement portion is provided at a position that allows the box side engagement portion to move from the engagement portion insertion groove into the engagement portion accommodation notch portion by an attaching rotation operation. An engagement portion reverse movement preventing claw is provided as the reverse rotation prevention portion that prevents the box side engagement portion from moving backward to the engagement portion insertion groove side by elastically returning along with the movement into the portion. The flow meter according to claim 6.   The engagement portion reverse movement preventing claw is fixed at the proximal end to the inner surface on the opposite side to the engagement portion receiving notch portion of the engagement portion insertion groove, and the other end side is engaged with the engagement portion. The flowmeter according to claim 7, wherein the flowmeter extends in a circumferential direction of the cylindrical fixing portion toward a part accommodating notch.   In the central axis direction, the engagement portion reverse movement preventing claw has a lower surface between the lower inner side surface of the engagement portion accommodating notch and a gap smaller than the thickness of the box side engagement portion. The box-side engaging portion elastically deforms the engaging portion reverse movement preventing claw upward to expand the gap. The flowmeter according to claim 8, wherein the flowmeter is accommodated in the engaging portion accommodating notch through the expanded gap in association with the assembly rotation operation.   The flowmeter according to claim 8 or 9, wherein a front end surface of the engagement portion reverse movement preventing claw is a cut surface along the central axis direction. The upper surface side of the box part assembled in a state where the fluoroscopic shielding member is interposed with the elastic seal ring by the assembly member is exposed at its upper surface side opening, and along the periphery of the upper surface side opening. A cylindrical upper case in which a case holding rib for retaining the outer peripheral edge of the upper surface of the box portion extends radially inward is fixed to the upper case in a detachable manner at the lower end of the upper case. An outer elastic member disposed between the lower case and the upper case and the lower case, and compressed and deformed in the direction of the central axis in a fixed state between the upper case and the lower case. A sealing member,
By performing an assembly rotation operation to the bayonet mechanism to the rotation completion angle position, the assembly member side engagement portion is engaged with the box side engagement portion while compressing and deforming the elastic seal ring. The inside of the box part is in a loose seal fixed state in which the elastic seal ring is sealed. Further, the upper case is disposed with respect to the box part in the loose seal fixed state, and the outer peripheral edge of the upper surface of the box part is the above-mentioned While the upper case 1 and the lower case 7 are fixed and the outer elastic seal member is compressed and deformed in the direction of the central axis while being arranged so as to be retained by the case holding rib, the upper case is By pressing the assembly member downward in the central axis direction and compressing and deforming the elastic seal ring in the central axis direction, Flow meter according to the internal box portion in any one of the loose seal than the fixed state formed by the main sealing fixed state compression of the resilient seal ring 4 is greater claims 1 to 10.   The flow meter according to claim 11, wherein an inner diameter of the opening of the upper case is set larger than an inner diameter of the assembly member.

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