Diaphragm-type pressure measurement chamber and production method for diaphragm for use in same

Abstract

A diaphragm (15) of a pressure measurement chamber (1) has: an annular support frame (40) that is made of a hard first material and is positioned between a first circumferential part (23) and a second circumferential part (33); and a flexible membrane (50) that is made of a second material that is softer than the first material and includes a membrane part (51) that is positioned between a first chamber (13a) and a second chamber (13b) and a flange part (52) that is provided around the membrane part (51) and engages the support frame (40). At least one of the flange part (52) and the support frame (40) has a plurality of protruding engagement parts (61, 42) that are provided along the circumferential direction and extend in a first direction, and the other has a plurality of recessed or hole-shaped engaged parts (41, 62) into which the engagement parts are fitted.

Description

Diaphragm-Type Pressure Measurement Chamber and Method for Manufacturing Diaphragm Used Therein

[0001] The present invention relates to a diaphragm-type pressure measurement chamber for measuring the pressure of blood flowing through a blood circuit and a method for manufacturing a diaphragm used therein.

[0002] There is a blood purification therapy in which a patient's blood is circulated extracorporeally and purified during the circulation. As an example of such treatment, dialysis therapy is known. In dialysis therapy, blood drawn from a patient is introduced into a dialyzer, where unnecessary components in the blood are replaced with useful components in the dialysate and filtration is also performed, and the treated blood is returned to the patient again. In such dialysis therapy, in order to prevent damage to useful blood cells and aggregation of blood, the pressure of the blood is measured at various locations in the blood circuit through which the blood flows.

[0003] As an instrument used for measuring the pressure of blood, for example, a pressure sensor is proposed in Patent Document 1. This pressure sensor has a configuration in which a liquid chamber through which blood flows and an air chamber communicating with the pressure sensor are partitioned by a flexible diaphragm.

[0004] Japanese Patent Application Laid-Open No. 2008-051663

[0005] By the way, in measuring the pressure of blood in a blood circuit, a low pressure of -300 to 500 mmHg is to be measured. Therefore, in order to improve the measurement accuracy of the pressure, it is preferable that the flexibility of the membrane is high. However, a membrane with high flexibility is easily deformed and difficult to maintain a certain shape, so it is difficult to handle during assembly. If wrinkles or distortions occur in the membrane during assembly, it may also affect the measurement accuracy of the pressure.

[0006] Therefore, an object of the present disclosure is to provide a diaphragm-type pressure measurement chamber that is easy to assemble and can be appropriately assembled, and a method for manufacturing a diaphragm used therein.

[0007] A diaphragm-type pressure measuring chamber according to a first aspect of the present disclosure is a diaphragm-type pressure measuring chamber for measuring the pressure of blood in a blood circuit, comprising: a first case having a first circumferential portion; a second case having a second circumferential portion and connected to the first case to form a chamber space between the first case and the second case; and a diaphragm provided between the first case and the second case in a first direction, dividing the chamber space into a first chamber between the first case and the second case and a second chamber between the second case, wherein the diaphragm is made of a rigid first material The flexible membrane comprises an annular support frame located between the first and second circumferential portions, a membrane portion located between the first and second chambers and having a three-dimensional shape in which at least a part is convex in the first direction, and a flange portion provided around the membrane portion and engaging with the support frame, the second material being softer than the first material, wherein at least one of the flange portion and the support frame is provided with a plurality of convex engaging portions extending in the first direction along the circumferential direction, and the other is provided with a plurality of concave or perforated engaged portions into which the engaging portions fit.

[0008] As a result, the diaphragm is configured such that the outer circumference is less prone to deformation compared to the membrane portion due to the support frame, improving handling during assembly and reducing the risk of wrinkles or distortion in the membrane during assembly. Furthermore, because the flexible membrane is connected at multiple points by the fitting of the engaging portion and the engaged portion, it is difficult for the flexible membrane to physically detach from the support frame. In addition, when efficiently manufacturing diaphragms, it is conceivable to manufacture the flexible membrane and support frame integrally by two-color molding. In this case, if the pressure for filling the mold with resin is not properly adjusted, adhesion failure may occur between the flexible membrane and the support frame. However, in this disclosure, since engaging portions and engaged portions are provided, even if adhesion failure occurs, the occurrence of the flexible membrane detaching from the support frame can be reduced.

[0009] A pressure measuring chamber according to a second aspect of the present disclosure further, in the first aspect, the diaphragm may have the flange portion provided with the engaging portion and the support frame provided with the engaged portion, and the flange portion provided with the engaged portion and the support frame provided with the engaging portion.

[0010] This further increases the connection strength between the diaphragm and the support frame.

[0011] In a third aspect of the present disclosure, the pressure measuring chamber, in the first or second aspect, further comprises the diaphragm, wherein the peripheral edge portion located on the outer circumference side of the membrane portion may have the support frames positioned at both ends in the first direction.

[0012] This ensures a stable posture when the diaphragm is placed on a feeder for transport during manufacturing or assembly, regardless of which of the two ends in the first direction is in contact with the feeder's mounting surface.

[0013] In any of the first to third embodiments of the pressure measuring chamber according to the fourth aspect of the present disclosure, a notch may be provided on one or the other surface of the support frame in the first direction, which opens on the one or the other surface in the first direction.

[0014] This allows for the appropriate suppression of sink marks during the molding of the support frame, enabling the support frame to be manufactured with high precision.

[0015] A pressure measuring chamber according to a fifth aspect of the present disclosure further, in the fourth aspect, has a plurality of notches provided in the circumferential direction of the support frame, and a bridging portion may be provided between two adjacent notches.

[0016] This allows for the precise manufacturing of the support frame while ensuring its strength.

[0017] A pressure measuring chamber according to a sixth aspect of the present disclosure may further, in any of the first to fifth aspects, have a diaphragm that is reversible, having a front surface and a back surface, and can be assembled to the first case and the second case with the front surface facing either one side in the first direction or the other side.

[0018] A pressure measuring chamber according to a seventh aspect of the present disclosure may further, in any of the first to sixth aspects, have a diaphragm manufactured by integral injection molding, comprising a primary step of forming the support frame and a secondary step of integrally forming the flexible membrane with respect to the support frame.

[0019] A pressure measuring chamber according to an eighth aspect of the present disclosure is a diaphragm-type pressure measuring chamber for measuring the pressure of blood in a blood circuit, comprising: a first case having a first circumferential portion; a second case having a second circumferential portion and connected to the first case to form a chamber space between the first case and the second case; and a diaphragm provided between the first case and the second case in a first direction, having a front surface and a back surface, and dividing the chamber space into a first chamber between the first case and the second case and a second chamber between the second case, wherein the diaphragm comprises an annular support frame made of a rigid primary material and located between the first circumferential portion and the second circumferential portion; a membrane portion located between the first chamber and the second chamber and having a three-dimensional shape in which at least a part is convex in the first direction; and a flange portion provided around the membrane portion and engaging with the support frame, and a flexible membrane made of a second material softer than the first material, wherein the peripheral portion of the diaphragm located on the outer circumference side of the membrane portion is The diaphragm has a clamped portion sandwiched between the first and second circumferential portions, and an annular outer peripheral projection that includes the support frame and is located on the outer circumference of the clamped portion and protrudes on both sides in the first direction. The first case and the second case, when assembled, have an annular housing space in which the outer peripheral projection is housed. The housing space is partitioned by a first groove formed in the first circumferential portion and a second groove formed in the second circumferential portion. One of the first and second grooves is an engagement groove that can engage with either one side of the outer peripheral projection in the first direction or the other side in the first direction, while the other of the first and second grooves is a receiving groove that can receive either one side of the outer peripheral projection in the first direction or the other side in the first direction. The diaphragm is reversible, so that the outer peripheral projection is housed in the housing space whether the surface is facing one side or the other side in the first direction, and can be assembled to the first case and the second case in a reversible manner.

[0020] As a result, the diaphragm's outer circumference is less prone to deformation compared to the membrane portion due to the support frame, improving handling during assembly and reducing the risk of wrinkles or distortion in the membrane during assembly. Furthermore, the diaphragm can be used reversibly by orienting the membrane surface in one direction during assembly. Therefore, for example, in the case of a diaphragm with a dome-shaped membrane portion, a pressure measuring chamber used for negative pressure measurement and a pressure measuring chamber used for positive pressure measurement can be manufactured by reversing the orientation of a single type of diaphragm, thereby enabling the commonality of parts.

[0021] A method for manufacturing a diaphragm according to a ninth aspect of the present disclosure is a two-color molding method for manufacturing a diaphragm for a pressure measuring chamber, comprising an annular support frame made of a hard primary material and a flexible membrane made of a softer secondary material, including a dome-shaped membrane portion and a flange portion provided around the membrane portion and engaging with the support frame, the method comprising: a primary step of injecting molten primary material into a primary cavity formed by a common mold and a primary mold to form the support frame; and a secondary step of, with the support frame held in the common mold, releasing the primary mold from the common mold in a first direction, and then injecting molten secondary material into a secondary cavity formed by the common mold and a secondary mold to integrally mold the flexible membrane to the support frame.

[0022] The diaphragm described above has a structure in which the outer circumference is less prone to deformation compared to the membrane portion due to the support frame, improving handling during assembly and thus reducing the risk of wrinkles or distortion in the membrane during assembly. Incidentally, as described above, the chambers of the first to eighth embodiments are composed of different materials for the diaphragm's support frame and flexible membrane. Such diaphragms can be manufactured integrally by a two-color molding method in which the molds are changed for each material and injection molding is performed. The ninth embodiment of this disclosure provides a suitable manufacturing method for manufacturing such a diaphragm by two-color molding. Specifically, as described above, this manufacturing method comprises a primary step of forming the support frame with a hard primary material and a secondary step of forming the flexible membrane with a soft secondary material.

[0023] As a result, the rigid support frame is formed before the flexible membrane. Therefore, deformation of the previously formed support frame by the secondary material injected into the mold at a predetermined pressure in the secondary process can be prevented. In other words, if the flexible membrane is formed first and then the support frame is formed, the injection pressure of the primary material for the support frame may deform the flexible membrane inside the mold. If the flexible membrane deforms, the primary material for the support frame may enter the void created by the deformation, which is undesirable. In contrast, the manufacturing method according to the ninth aspect of this disclosure prevents such a situation from occurring, and makes it possible to manufacture diaphragms with high precision even with an integral molding method by injection molding.

[0024] This disclosure provides a diaphragm-type pressure measuring chamber that is easy to assemble and can be properly assembled, and a suitable manufacturing method for the diaphragm used therein.

[0025] Figure 1 is a perspective view showing the configuration of a diaphragm-type pressure measuring chamber according to Embodiment 1. Figure 2A is a longitudinal cross-sectional view of the pressure measuring chamber, Figure 2B is an enlarged cross-sectional view showing a part of Figure 2A, and Figure 2C is an enlarged cross-sectional view showing a part of Figure 2B (only the diaphragm portion). Figure 3 is a longitudinal cross-sectional view of the pressure measuring chamber, showing the configuration when the diaphragm is installed upside down in the configuration of Figure 2A. Figure 4 shows a perspective view of the diaphragm viewed from diagonally above, a perspective view viewed from diagonally below, and a plan view, arranged from top to bottom. Figure 5A is a perspective view of the flexible membrane, and Figure 5B is a perspective view of the support frame. Figure 6A is a cross-sectional view of the diaphragm along line A-A, Figure 6B is a cross-sectional view of the flexible membrane along line A-A, and Figure 6C is a cross-sectional view of the support frame along line A-A. Figure 7A is a cross-sectional view of the diaphragm along line B-B, Figure 7B is a cross-sectional view of the flexible membrane along line B-B, and Figure 7C is a cross-sectional view of the support frame along line B-B. Figure 8 is a flowchart showing a method for manufacturing a diaphragm by two-color molding. Figure 9 is a schematic cross-sectional view illustrating a method for manufacturing a diaphragm. Figure 10A is a perspective view of the diaphragm according to Modification 1, seen from diagonally above, and Figure 10B is a plan view of the diaphragm according to Modification 1. Figure 11A is a perspective view of the flexible membrane according to Modification 1, and Figure 11B is a perspective view of the support frame according to Modification 1. Figure 12A is a cross-sectional view of Figure 10B along line C-C, and Figure 12B is a cross-sectional view of Figure 10B along line D-D. Figure 13A is a perspective view of the diaphragm according to Modification 2, seen from diagonally above, and Figure 13B is a plan view of the diaphragm according to Modification 2. Figure 14A is a perspective view of the flexible film according to Modification 2, and Figure 14B is a perspective view of the support frame according to Modification 2. Figure 15A is a cross-sectional view taken along the line E-E in Figure 13B, and Figure 15B is a cross-sectional view taken along the line F-F in Figure 13B.

[0026] (Embodiments) Hereinafter, a diaphragm-type pressure measuring chamber according to an embodiment of the present disclosure will be described with reference to the drawings. The concept of direction used in the following description is for convenience of explanation and does not limit the orientation of the components of each disclosure to that direction. Furthermore, the pressure measuring chamber described below is only one embodiment of the present disclosure. Therefore, the present disclosure is not limited to the following embodiments, and additions, deletions, or modifications to the components are possible without departing from the spirit of the disclosure.

[0027] The diaphragm-type pressure measuring chamber 1 according to this disclosure, for example, constitutes part of the blood circuit of a dialysis system and measures the pressure of the patient's blood flowing through the blood channels of the blood circuit. The blood circuit includes, for example, a blood withdrawal line which is a blood channel that leads the patient's blood out of the body, a filter connected to the blood withdrawal line that transfers specific components from the patient's blood to the dialysate to purify the blood, and a blood return line which is a blood channel that returns the purified blood to the patient. A blood pump for supplying blood to the blood circuit is also provided in the middle of the blood withdrawal line.

[0028] The dialysis system is equipped with a pressure measuring device in addition to the blood circuit. The pressure measuring device has multiple pressure sensors inside the device, and each pressure sensor is connected to various points (pressure measurement points) in the blood circuit via a pressure monitoring line. A pressure measuring chamber 1 according to this disclosure is provided between such a pressure monitoring line and the pressure measurement points of the blood circuit.

[0029] The pressure measuring chamber 1 may be installed in the middle of a blood flow line in the blood circuit, forming part of that line. Alternatively, the pressure measuring chamber 1 may be installed so as to be connected to another line that branches off from the blood flow line in the blood circuit via a drip chamber or the like. In the former case, blood flows through the inside of the pressure measuring chamber 1 (the first chamber 13a described below). In the latter case, blood does not flow through the inside of the pressure measuring chamber 1 in principle, the second port P2 is closed, and air in contact with the blood on the blood circuit flows through the inside of the pressure measuring chamber 1 (the first chamber 13a).

[0030] The configuration of the pressure measuring chamber 1 will be described in detail below. Figure 1 is a perspective view showing the configuration of the diaphragm-type pressure measuring chamber 1 according to this embodiment 1. Figure 2A is a longitudinal cross-sectional view of the pressure measuring chamber 1, Figure 2B is an enlarged cross-sectional view showing a part of Figure 2A, and Figure 2C is an enlarged cross-sectional view showing a part of Figure 2B (only the diaphragm 15 portion).

[0031] The pressure measuring chamber 1 comprises a first case 11 having a first circumference 23, a second case 12 having a second circumference 33 and connected to the first case 11 to form a chamber space 13 between them, and a diaphragm 15. Both the first case 11 and the second case 12 are made of resin, and together they form a housing 14. The diaphragm 15 is provided inside this housing 14.

[0032] The diaphragm 15 is provided between the first case 11 and the second case 12 in a first direction (corresponding to the "up and down direction" in this embodiment), and divides the chamber space 13 into a first chamber 13a between the first case 11 and the second chamber 13b between the first case 11 and the second case 12. The first case 11 has a first port (inlet port) P1 and a second port (outlet port) P2, and the second case 12 has a third port (pressure port) P3.

[0033] The pressure measuring chamber 1 has a generally circular dome shape, and its orientation during use is not particularly limited. However, for the sake of explanation below, the directions of the pressure measuring chamber 1 are defined as follows: The direction in which the second case 12 is located relative to the first case 11 is defined as "upward," and the opposite direction is defined as "downward." Also, the direction in which the second port P2 is located relative to the first port P1 is defined as "forward," and the opposite direction is defined as "rearward." Furthermore, the direction that intersects both the up-down and front-back directions is defined as the "left-right direction," with the forward direction as the reference point.

[0034] Furthermore, in this embodiment, as shown in Figure 1, a dome-shaped pressure measuring chamber 1 that is circular in plan view (when viewed from above) and bulges upward in an arc shape in side view is used as an example for explanation, but the configuration of the pressure measuring chamber 1 is not limited to this. For example, it may be an egg-shaped pressure measuring chamber that is elliptical in plan view and bulges upward in an arc shape in side view. Other shapes are also possible. Moreover, the mounting positions of the various ports on the housing and the opening direction of the ports are not particularly limited.

[0035] The configurations of Case 11, Case 2, and the diaphragm 15 will be described in detail below.

[0036] [First Case] ​​The first case 11 comprises a case body 20 to which a first port P1 and a second port P2 are connected. The case body 20 is generally dome-shaped, bulging downwards, and has an opening 21 that opens upwards, while its inner surface 22 is recessed downwards. The inner surface 22 and the lower surface of the diaphragm 15 form the first chamber (blood-side space) 13a, which is the lower space of the chamber space 13. That is, the first chamber 13a is a space formed between the first case 11 and the diaphragm 15, and is a space that communicates with the blood flow path in the blood circuit.

[0037] In this embodiment, the inner surface 22 of the first case 11 disclosed has an arc-shaped contour in its longitudinal section (a cross-section in a plane parallel to the vertical and front-to-back directions), and also an arc-shaped contour in its transverse section (a cross-section in a plane parallel to the vertical and left-to-right directions). However, the contour shape of the inner surface 22 in cross-section is not limited to this; for example, it may be elliptical or rectangular, and the contours in the longitudinal section and the transverse section may be different.

[0038] The opening 21 of the case body 20 has a first circumferential portion 23 that expands in the radial direction from the upper end of the inner surface 22 and encircles the opening 21. This first circumferential portion 23 supports the diaphragm 15 between itself and the second circumferential portion 33 of the second case 12, which will be described later.

[0039] The first circumferential portion 23 has an inner circumferential wall 24, an outer circumferential wall 25, and a lower wall 26. The inner circumferential wall 24 is substantially identical to the portion of the case body 20 near the opening, and the upper end of the inner circumferential wall 24 forms the opening 21. The outer circumferential surface of this inner circumferential wall 24 is a surface parallel to the vertical direction and surrounds the opening 21. The outer circumferential wall 25 is located a predetermined distance outward from the inner circumferential wall 24, and its inner circumferential surface is a surface parallel to the vertical direction, similar to the outer circumferential surface of the inner circumferential wall 24. The lower wall 26 is a wall connecting the lower part of the inner circumferential wall 24 and the lower part of the outer circumferential wall 25, and its upper surface is a surface perpendicular to the vertical direction, connecting the outer circumferential surface of the inner circumferential wall 24 and the inner circumferential surface of the outer circumferential wall 25.

[0040] The first circumferential portion 23 has a first groove 27. The first groove 27 is defined by the outer surface of the inner circumferential wall 24, the inner surface of the outer circumferential wall 25, and the upper surface of the lower wall 26, and its cross-section is a rectangular shape that opens upward. For example, the cross-sectional shape of the first groove 27 may be rectangular, square, trapezoidal, etc., but is not limited to such a rectangular shape; for example, it may have a U-shaped cross-section depending on the shape of the outer periphery 56 of the diaphragm 15. The upper end of the inner circumferential wall 24 forms a first contact portion 24a that abuts against the diaphragm 15 and maintains the airtightness and liquid tightness of the first chamber 13a.

[0041] A first port P1 is integrally provided at the rear of the case body 20. The first port P1 is cylindrical, and its internal flow path communicates with the first chamber 13a inside the case body 20. A second port P2 is integrally provided at the front of the case body 20. The second port P2 is cylindrical, and its internal flow path also communicates with the first chamber 13a. The flow paths of these two ports P1 and P2 are arranged so that their flow centerlines are oriented in the front-to-back direction, and their centerlines are offset to the left and right from each other.

[0042] Note that the arrangements of the first port P1 and the second port P2 are not limited to the above example. For example, the first port P1 and the second port P2 may be coaxially arranged such that their flow center lines coincide with each other, or may be arranged such that their flow center lines intersect at a predetermined angle (such as 45 degrees or 90 degrees). Further, it is more preferable to provide grooves or protrusions on the inner surface 22 of the case body 20 so that even when the diaphragm 15 is depressed downward and contacts the inner surface 22, a space that communicates with the internal flow path of the first port P1 and contacts the flexible film 50 of the diaphragm 15 is secured to enable pressure measurement.

[0043] [Second Case] The second case 12 includes a case body 30, and a third port P3 is connected to this case body 30. The case body 30 generally forms a dome shape that bulges upward, has an opening 31 that opens downward, and the inner surface 32 is recessed upward. And the second chamber (sensor-side space) 13b, which is the upper space in the chamber space 13, is formed by the inner surface 32 and the upper surface of the diaphragm 15. That is, the second chamber 13b is a space formed between the second case 12 and the diaphragm 15, and is a space that communicates with a pressure monitor line extending from the pressure measuring device.

[0044] The inner surface 32 of the second case 12 disclosed in the present embodiment is, like the inner surface 22 of the first case 11, such that the contours of both the longitudinal section and the cross section are arc-shaped. However, the shape of each contour is not limited to this, and for example, an elliptical shape or a rectangular shape may be used, or the contours may be different between the longitudinal section and the cross section.

[0045] A second peripheral portion 33 that extends in the diameter-expanding direction from the lower end portion of the inner surface 32 and circulates around the opening 31 is formed at the opening 31 of the case body 30. This second peripheral portion 33 supports the diaphragm 15 between it and the first peripheral portion 23 of the first case 11 described above.

[0046] The second peripheral portion 33 has an inner peripheral wall 34, an outer peripheral wall 35, and an upper wall 36. The inner peripheral wall 34 is substantially the same as the vicinity of the opening of the case body 30, and the lower end of the inner peripheral wall 34 forms an opening 31. The outer peripheral surface of the inner peripheral wall 34 is a surface parallel to the vertical direction and surrounds the periphery of the opening 31. The outer peripheral wall 35 is located at a predetermined distance away from the inner peripheral wall 34 on the outer peripheral side, and its inner peripheral surface is a surface parallel to the vertical direction like the outer peripheral surface of the inner peripheral wall 34. The upper wall 36 is a wall connecting between the upper part of the inner peripheral wall 34 and the upper part of the outer peripheral wall 35, and its lower surface is a surface orthogonal to the vertical direction and connects the outer peripheral surface of the inner peripheral wall 34 and the inner peripheral surface of the outer peripheral wall 35.

[0047] The second peripheral portion 33 has a second groove 37. The second groove 37 is defined by the outer peripheral surface of the inner peripheral wall 34, the inner peripheral surface of the outer peripheral wall 35, and the lower surface of the upper wall 36 described above, and has a rectangular cross-section opened downward. For example, the cross-sectional shape of the second groove 37 may be a rectangular shape, a square shape, a trapezoidal shape, etc., but is not limited to such rectangular shapes, and may be an inverted U-shaped cross-section according to the shape of the outer peripheral edge portion 56 of the diaphragm 15. The lower end of the inner peripheral wall 34 forms a second contact portion 34a that contacts the diaphragm 15 to maintain the airtightness and liquid tightness of the second chamber 13b.

[0048] A third port P3 is integrally provided at the upper part of the case body 30. A pressure monitor line extending from the pressure measuring device described above is connected to the third port P3. The third port P3 has a cylindrical shape, and its flow center line is directed in the front-rear direction. The rear end of the internal passage of the third port P3 communicates with the second chamber 13b through the uppermost opening 32a of the inner surface 32.

[0049] The arrangement of the third port P3 is not limited to the above example; for example, it may be arranged so that the flow centerline is oriented vertically, or it may be arranged to face any other direction. Furthermore, the third port P3 may be configured to be directly connected to and locked to the pressure measuring device without going through a pressure monitoring line (tube, etc.). It is also preferable to provide grooves or protrusions on the inner surface 32 of the case body 30 so that even when the diaphragm 15 bulges upward and comes into contact with the inner surface 32, there is still space to communicate with the internal flow path of the third port P3 and to contact the flexible membrane 50 of the diaphragm 15, thereby enabling pressure measurement.

[0050] [Diaphragm] As shown in Figures 2A and 2C, the diaphragm 15 has an annular support frame 40 made of a rigid first material and a flexible membrane 50 made of a second material that is softer than the first material. The flexible membrane 50 has a dome-shaped membrane portion 51 and a flange portion 52 provided around the membrane portion 51 that engages with the support frame 40. In this embodiment, the rigid first material is polypropylene (PP) and the soft second material is an elastomer. However, the materials are not limited to these, and various known materials can be selected. That is, the first material forming the support frame 40 should be a material that is harder than the second material forming the flexible membrane 50. For example, the rigid first material can be rigid PP (rigid polypropylene), polycarbonate, etc., and the soft second material can be thermoplastic elastomer, isoprene rubber, silicone rubber, soft PVC (soft polyvinyl chloride), etc.

[0051] Furthermore, the dome-shaped membrane portion 51 is configured, for example, to bulge upward in a convex direction along the first direction. Note that the shape of the membrane portion 51 is not limited to a dome shape; it is sufficient if at least a part of it has a three-dimensional shape that is convex in the first direction, and other shapes such as a wave shape can also be adopted. In the case of a flat plate that does not have a three-dimensional shape, elastic force is always generated when the membrane portion deforms in the first direction. However, when the membrane portion has a three-dimensional shape, the membrane portion has a structure that can be easily bent within a specific range, so elastic force is less likely to be generated during deformation, and the responsiveness to pressure can be improved.

[0052] The diaphragm 15 can be manufactured integrally by two-color molding of a support frame 40 and a flexible membrane 50 made of different materials. The flange portion 52 has a first flange portion (clamped portion) 53 located on the outer circumference side of the membrane portion 51 and a second flange portion 54 located further outward from the first flange portion 53, with the second flange portion 54 connected (engaged) to the support frame 40 by two-color molding. The first flange portion 53 extends in the expanding diameter direction from the outer circumference end of the membrane portion 51 and encircles the membrane portion 51, and its thickness dimension in the vertical direction is substantially constant, forming a "clamped portion" sandwiched between the first circumference portion 23 and the second circumference portion 33.

[0053] Furthermore, in the diaphragm 15, the portion located on the outer periphery of the membrane portion 51, that is, the portion consisting of the support frame 40 and the flange portion 52, forms the peripheral edge portion 55. In this peripheral edge portion 55, the outer peripheral edge portion (outer peripheral projection) 56, which is located on the outer periphery of the first flange portion 53 and consists of the support frame 40 and the second flange portion 54, has a shape that protrudes upward and downward from the first flange portion 53. That is, the outer peripheral edge portion 56 has a first projection 57 that protrudes downward (in the opposite direction to the convex direction) from the first flange portion 53, and a second projection 58 that protrudes upward (in the convex direction). This outer peripheral edge portion 56 includes the support frame 40 and forms an annular "outer peripheral projection" that is on the outer periphery of the clamped portion (first flange portion 53) and protrudes on both sides in the vertical direction.

[0054] The dome-shaped membrane portion 51 can be configured such that the ratio of the height dimension H to the width dimension W, H / W, is 0.1 or more and 0.6 or less, and more preferably, a configuration in which H / W is 0.2 or more and 0.5 or less can be suitably adopted. This makes it possible to increase the amount of displacement of the membrane portion 51 in response to pressure changes without excessively increasing the height dimension, thereby improving the accuracy of pressure detection. The configuration of the peripheral portion 55 of the diaphragm 15 will be described in more detail later.

[0055] [Assembly Method of Pressure Measuring Chamber] The pressure measuring chamber 1 is constructed by combining the housing 14, which consists of the first case 11 and the second case 12 as described above, and the diaphragm 15. Specifically, first, the diaphragm 15, for example, in an upwardly bulging position (downward opening position), is assembled from above into the first case 11 with its opening 21 facing upward. At this time, the second protrusion 58 of the peripheral edge 55 of the diaphragm 15 is inserted into the first groove 27 of the first peripheral portion 23 of the first case 11. Also, the first contact portion 24a, which is the upper end of the inner peripheral wall 24 of the first case 11, contacts the lower surface of the first flange portion (clamped portion) 53 of the diaphragm 15.

[0056] Next, the second case 12 is assembled to the first case 11 in this state from above, with its opening 31 facing downwards. At this time, the second circumferential portion 33 of the second case 12 is positioned opposite the first circumferential portion 23 of the first case 11. The first projection 57 of the peripheral edge 55 of the diaphragm 15 is inserted into the second groove 37 of the first circumferential portion 33 of the second case 12. Furthermore, the second contact portion 34a, which is the lower end of the inner circumferential wall 34 of the second case 12, contacts the upper surface of the first flange portion (clamped portion) 53 of the diaphragm 15.

[0057] In this state, the first circumferential portion 23 of the first case 11 and the second circumferential portion 33 of the second case 12 are connected (for example, by adhesive bonding or ultrasonic welding). In this embodiment, the outer peripheral wall 25 of the first circumferential portion 23 is located inside the outer peripheral wall 35 of the second circumferential portion 33, and the upper end of the outer peripheral wall 25 of the first circumferential portion 23 abuts against the lower surface of the upper wall 36 of the second circumferential portion 33. This abutting portion is then connected by adhesive or by ultrasonic bonding from the upper surface of the upper wall 36.

[0058] In this way, the first case 11 and the second case 12 are connected, and the diaphragm 15 is supported between them. As a result, the support frame 40 is located between the first circumferential portion 23 and the second circumferential portion 33, and the membrane portion 51 is located between the first chamber 13a and the second chamber 13b. In addition, the first flange portion 53, which is the clamped portion of the diaphragm 15, is clamped from above and below by the first contact portion 24a and the second contact portion 34a. Thus, the first circumferential portion 23 and the second circumferential portion 33 are connected in an airtight and liquidtight manner with the first flange portion 53 in between.

[0059] [Reversible Specification] The pressure measuring chamber 1 according to this embodiment has a reversible diaphragm 15 that can be incorporated into the housing 14 even if its upright or downright orientation is reversed. Therefore, for example, a pressure measuring chamber used for negative pressure measurement and a pressure measuring chamber used for positive pressure measurement can be manufactured by reversing the orientation of a single type of diaphragm and incorporating it, thereby enabling the commonality of parts. However, the pressure measuring chamber 1 is not limited to having a reversible diaphragm 15, and may also have a configuration in which the orientation in which it is incorporated into the housing 14 is fixed to one.

[0060] Let me explain in detail. As shown in Figure 2B, the space partitioned by the first groove 27 and the second groove 37 in the housing 14 forms a rectangular cross-sectional accommodation space 16, and its radial width is approximately the same at any position in the vertical direction. This accommodation space 16 is annular in shape and is a space that accommodates the outer peripheral edge 56, which is the protruding part of the outer circumference of the diaphragm 15.

[0061] On the other hand, the peripheral edge 55 of the diaphragm 15 has a rectangular cross-section, as shown in Figure 2C, and its radial width (thickness) is substantially the same at any position in the vertical direction. That is, the first protrusion 57 and the second protrusion 58 of the peripheral edge 55 have substantially the same thickness. Therefore, either the first protrusion 57 or the second protrusion 58 can be inserted into the first groove 27, and either the first protrusion 57 or the second protrusion 58 can be inserted into the second groove 37. In this embodiment, as shown in Figures 2B and 2C, an example is shown in which the housing space 16 consisting of the first groove 27 and the second groove 37 houses other components (in this case, the outer peripheral wall 25 of the first case 11) along with the outer peripheral edge (outer peripheral protrusion) 56, but the embodiment is not limited to this. The first groove 27 and the second groove 37 may be configured to house only the outer peripheral edge 56.

[0062] In other words, one of the first groove 27 and the second groove 37 forms an "engagement groove" that can engage with either one side (e.g., the first protrusion 57) or the other side (e.g., the second protrusion 58) in the vertical direction of the outer peripheral edge (outer peripheral protrusion) 56. The other of the first groove 27 and the second groove 37 forms a "receiving groove" that can be received by either one side (e.g., the first protrusion 57) or the other side (e.g., the second protrusion 58) in the vertical direction of the outer peripheral edge (outer peripheral protrusion) 56.

[0063] As a result, the diaphragm 15 can be assembled into the housing 14 in a first position with the convex direction of the membrane portion 51 facing upward, as shown in Figure 2A, and can also be assembled into the housing 14 in a second position with the convex direction of the membrane portion 51 facing downward, as shown in Figure 3. In other words, if one side of the membrane portion 51 is the front surface and the other side is the back surface, the outer peripheral portion (outer peripheral protrusion) 56 can be accommodated in the housing space 16 regardless of whether the front surface is facing up or down. That is, the diaphragm 15 is reversible and can be assembled into the first case 11 and the second case 12 in a reversible manner. Note that in order to make it reversible, the cross-sectional shape of the outer peripheral portion 56 of the diaphragm 15 is not necessarily rectangular, and it is preferable that the first protrusion 57 and the second protrusion 58 have an up-and-down symmetrical shape.

[0064] Here, when the diaphragm 15 is in the first position, the first projection 57 is inserted into the first groove 27 and the second projection 58 is inserted into the second groove 37, and the first circumferential portion 23 and the second circumferential portion 33 are connected airtight and liquid-tight with the first flange portion 53 in between. Also, when the diaphragm 15 is in the second position, the second projection 58 is inserted into the first groove 27 and the first projection 57 is inserted into the second groove 37, and the first circumferential portion 23 and the second circumferential portion 33 are connected airtight and liquid-tight with the first flange portion 53 in between.

[0065] Furthermore, the height dimension of the first projection 57 (i.e., the height dimension from the first flange portion 53) is the same as or smaller than the depth dimension of the first groove 27 (i.e., the height dimension of the inner surface of the inner circumferential wall 24), and the depth dimension of the second groove 37 (i.e., the height dimension of the inner surface of the inner circumferential wall 34). Similarly, the height dimension of the second projection 58 (i.e., the height dimension from the first flange portion 53) is the same as or smaller than the depth dimension of the first groove 27 (i.e., the height dimension of the inner surface of the inner circumferential wall 24), and the depth dimension of the second groove 37 (i.e., the height dimension of the inner surface of the inner circumferential wall 34). Therefore, in both the first and second orientations, the peripheral edge 55 has the same vertical dimension as the space formed by the first groove 27 and the second groove 37, or is slightly smaller than that space, leaving excess space.

[0066] [Engagement Structure of Support Frame and Flexible Membrane] The configuration of the diaphragm 15, in particular the engagement structure of the support frame 40 and the flexible membrane 50, will be described with reference to Figures 4 to 7. Figure 4 shows a perspective view of the diaphragm 15 from diagonally above, a perspective view from diagonally below, and a plan view, arranged vertically. The plan view shows cutting lines A-A and B-B. Figure 5A is a perspective view of the flexible membrane 50, and Figure 5B is a perspective view of the support frame 40. Figure 6A is a cross-sectional view of the diaphragm 15 along line A-A, Figure 6B is a cross-sectional view of the flexible membrane 50 along line A-A, and Figure 6C is a cross-sectional view of the support frame 40 along line A-A. Figure 7A is a cross-sectional view of the diaphragm 15 along line B-B, Figure 7B is a cross-sectional view of the flexible membrane 50 along line B-B, and Figure 7C is a cross-sectional view of the support frame 40 along line B-B.

[0067] As shown in Figure 5A, the flange portion 52 (more specifically, the second flange portion 54) of the flexible film 50 has multiple convex first engaging portions 61 extending downward in the circumferential direction along the second flange portion 54. In the example of Figure 5A, four first engaging portions 61 are provided at equal intervals in the circumferential direction. Also, as shown in Figure 5B, the support frame 40 is provided with hole-shaped first engaged portions 41 into which the first engaging portions 61 fit. In the example of Figure 5B, four first engaged portions 41 are provided at equal intervals in the circumferential direction corresponding to the first engaging portions 61.

[0068] Furthermore, as shown in Figure 5B, the support frame 40 is provided with multiple convex second engaging portions 42 extending upward in the circumferential direction along the support frame 40. In the example of Figure 5B, eight second engaging portions 42 are provided at equal intervals in the circumferential direction. In addition, as shown in Figure 5A, the second flange portion 54 of the flexible film 50 is provided with a hole-shaped second engaged portion 62 into which the second engaging portions 42 fit. In the example of Figure 5A, eight second engaged portions 62 are provided at equal intervals in the circumferential direction corresponding to the second engaging portions 42.

[0069] Although the first engaged portion 41 and the second engaged portion 62 have been described as having a hole-like configuration that penetrates vertically and is surrounded on all four sides by walls, the configuration is not limited to this. For example, the first engaged portion 41 may be concave with an open upper end and a closed lower end. Furthermore, the first engaged portion 41 may be a hole-like or concave shape that can engage with the first engaged portion 61 in the vertical direction, and a slit or notch may be provided in a part of the wall forming the first engaged portion 41. Similarly, the second engaged portion 62 may be concave with an open lower end and a closed upper end. The second engaged portion 62 may be a hole-like or concave shape that can engage with the second engaged portion 41 in the vertical direction, and a slit or notch may be provided in a part of the wall forming the second engaged portion 62.

[0070] In this embodiment, the diaphragm 15 engages with the first engaging portion 61 so as to fit inside the first engaged portion 41, and the second engaging portion 42 engages with the second engaged portion 62 so as to fit inside the second engaged portion 62. In this way, the support frame 40 and the flange portion 52 are connected at multiple points in the circumferential direction by a fitting structure consisting of the engaging portion and the engaged portion, making them difficult to detach. For example, in the process of transporting the diaphragm, if a force is applied to the flange portion radially inward, the fitting structure acts as an anchor, preventing the flange portion from coming off the support frame. Furthermore, the diaphragm 15, in which the support frame 40 and the flexible membrane 50 are integrated in this way, is less prone to deformation in the outer peripheral portion where the support frame 40 is provided, and has good shape retention. Therefore, handling is improved in various manufacturing and assembly situations, such as transporting the diaphragm 15, gripping the diaphragm 15 with a robot, and assembling the diaphragm 15 into the housing 14.

[0071] In this embodiment, a configuration in which both the support frame 40 and the flange portion 52 have an engaging portion and an engaged portion is illustrated, but the embodiment is not limited to this. That is, one of the support frame 40 and the flange portion 52 may have only an engaging portion, and the other may have only an engaged portion.

[0072] Let's further elaborate on one example of the engagement structure described above. First, let's explain the configuration of the support frame 40.

[0073] As shown in Figures 5B, 6C, and 7C, the support frame 40 is configured to form an annular shape with an inner wall portion 43, a plurality of intermediate wall portions 44, and an outer wall portion 45 forming layers. The inner wall portion 43, intermediate wall portions 44, and outer wall portion 45 all have approximately the same thickness, for example. Furthermore, the bottom surfaces of the inner wall portion 43 and the outer wall portion 45 are flush, and the height dimension of the outer wall portion 45 is greater than that of the inner wall portion 43.

[0074] In the example shown in Figure 5B, there are four intermediate wall sections 44 between the inner wall section 43 and the outer wall section 45, and each intermediate wall section 44 has an arc shape in plan view. Two adjacent intermediate wall sections 44 are separated by a predetermined distance, and this space forms the first engaged portion 41. That is, the first engaged portion 41 is the space between two adjacent intermediate wall sections 44 and between the inner wall section 43 and the outer wall section 45. This first engaged portion 41 has a hole shape that penetrates in the vertical direction.

[0075] Furthermore, a second engaging portion 42 is formed on the upper part of the intermediate wall portion 44. In the example shown in Figure 5B, two second engaging portions 42 are provided projecting from the upper part of one intermediate wall portion 44, separated by a predetermined distance along the circumferential direction. These second engaging portions 42 protrude upward from the upper surface of the outer wall portion 45. As an example, the pair of wall surfaces facing each other between the two second engaging portions 42 formed on one intermediate wall portion 44 are tapered such that the distance between them increases as they move upward. In this way, the support frame 40 is provided with two second engaging portions 42 and one first engaged portion 41 arranged in order along the circumferential direction.

[0076] Furthermore, as shown in the central drawing of Figure 4, the lower part of the intermediate wall section 44 is provided with a plurality of notches 46 and bridging sections 47 that open downwards on the lower surface. The notches 46 consist of bottomed concave spaces located between the inner wall section 43 and the outer wall section 45, and two are provided between two adjacent first engaged sections 41. Therefore, a total of eight notches 46 are provided. Bridging sections 47 are provided between two adjacent notches 46, and between the notches 46 and the first engaged sections 41, separating them and connecting the inner wall section 43 and the outer wall section 45. As can be seen from the above explanation, the eight second engaged sections 42 at the top of the intermediate wall section 44 and the eight notches 46 at the bottom are located in the same position in the circumferential direction.

[0077] Next, the structure of the flexible membrane 50 will be described.

[0078] As shown in Figures 5A, 6B, and 7B, the flange portion 52 of the flexible film 50 has a first flange portion 53 and a second flange portion 54 (see also Figure 2C). Of these, the first flange portion 53 has a constant thickness in the vertical direction as described above and extends in the expanding radial direction from the outer peripheral end of the film portion 51. Also, as shown in Figure 7B, the second flange portion 54 extends upward from the outer peripheral end of the first flange portion 53 and has a vertical wall portion 63 that encircles the first flange portion 53. Furthermore, the second flange portion 54 extends further in the expanding radial direction from the upper end of this vertical wall portion 63 and has an upper wall portion 64 that encircles the vertical wall portion 63. Note that the thickness dimension (radial dimension) of these vertical wall portions 63 and the thickness dimension (vertical dimension) of the upper wall portion 64 are both approximately the same as the thickness dimension of the first flange portion 53.

[0079] Multiple first engaging portions 61 extend downward from the lower surface of the upper wall portion 64. As shown in Figure 5A, the first engaging portions 61 are approximately rectangular parallelepipeds in shape, or wedge-shaped with a thickness that decreases as they extend downward. As shown in Figure 6B, the upper end of the first engaging portion 61 is connected to the lower surface of the upper wall portion 64, and its radial inner surface is connected to the outer surface of the vertical wall portion 63. The lower end of the first engaging portion 61 is located below the lower surface of the first flange portion 53. Four such first engaging portions 61 are provided at equal intervals along the circumferential direction of the second flange portion 54.

[0080] The upper wall portion 64 is provided with eight second engagement portions 62, each consisting of vertically oriented through holes. Specifically, in the circumferential direction of the second flange portion 54, two second engagement portions 62 are arranged between two adjacent first engagement portions 61.

[0081] The support frame 40 and the flexible membrane 50 are firmly connected by two-color molding, with the aforementioned engaging and engaged portions engaging with each other. Specifically, as shown in Figure 6A, the four downward-convex first engaging portions 61 of the flexible membrane 50 fit into the four perforated first engaged portions 41 of the support frame 40. Also, as shown in Figure 7A, the eight upward-convex second engaging portions 42 of the support frame 40 fit into the eight perforated second engaged portions 62 of the flexible membrane 50.

[0082] The peripheral edge 55 of the diaphragm 15 has support frames 40 positioned at both ends in the vertical direction (first direction). Specifically, referring to Figures 7A and 7C, the upper end surface of the second engaging portion 42 of the middle wall portion 44 of the support frame 40 forms a part of the uppermost end surface of the peripheral edge 55. Also, the lower end surface of the inner wall portion 43 and the lower end surface of the outer wall portion 45 of the support frame 40 form a part of the lowermost end surface of the peripheral edge 55. Therefore, the uppermost and lowermost end surfaces of the peripheral edge 55 are located on the support frame 40 made of a rigid first material. As a result, when the diaphragm 15 is placed on a conveying feeder (e.g., a vibrating conveyor) during manufacturing or assembly, for example, it can be placed in a stable position regardless of whether the upper or lower end of the peripheral edge 55 is in contact with the feeder's mounting surface. However, it is not essential that the support frame 40 is located on the uppermost and lowermost ends of the peripheral edge 55 of the diaphragm 15. A configuration in which the support frame 40 is not located on either the uppermost or lowermost end, or both, is also acceptable.

[0083] In this embodiment, the uppermost end surface of the peripheral portion 55 is composed of the upper end surface of the second engaging portion 42 of the support frame 40 described above and the upper surface of the upper wall portion 64 of the flexible film 50 which is flush with it (see also the upper view in Figure 4). The lowermost end surface of the peripheral portion 55 is composed of the lower end surface of the inner wall portion 43 and the lower end surface of the outer wall portion 45 of the support frame 40 described above and the lower end surface of the first engaging portion 61 of the flexible film 50 which is flush with it (see also the middle view in Figure 4).

[0084] As a result, the first engaging portion 61 extending downward extends to the lower opening end of the perforated first engaged portion 42, and the second engaging portion 41 extending upward extends to the upper opening end of the perforated second engaged portion 62. This ensures a large contact area between each engaging portion and the corresponding engaged portion, thereby improving the connection strength.

[0085] Furthermore, the first projection 57 that protrudes downward from the outer peripheral edge 56 includes the inner wall portion 43, the lower part of the outer wall portion 45, the first projection 61 positioned between them, and the notch portion 46, as shown in Figures 6A and 7A. Therefore, the radial thickness dimension of the first projection 57 is defined by the inner surface of the inner wall portion 43 and the outer surface of the lower part of the outer wall portion 45. This thickness dimension of the first projection 57 is constant at any point in the circumferential direction.

[0086] The second projection 58, which protrudes upward from the outer peripheral edge 56, includes the vertical wall portion 63, the upper wall portion 64, the upper part of the outer layer wall portion 45, and the second engagement portion 42. Therefore, the radial thickness dimension of the second projection 58 is defined by the inner surface of the vertical wall portion 63, the outer surface of the upper wall portion 64, and the upper surface of the outer layer wall portion 45. The thickness dimension of this second projection 58 is constant at any point in the circumferential direction.

[0087] Furthermore, the thickness dimensions of the first protrusion 57 and the second protrusion 58 are identical. In addition, the inner surface of the inner wall portion 43 that defines the inner thickness of the first protrusion 57 and the inner surface of the vertical wall portion 63 that defines the inner thickness of the second protrusion 58 are located at the same radial position. Similarly, the lower outer surface of the outer wall portion 45 that defines the outer thickness of the first protrusion 57 and the outer surface of the upper wall portion 46 and the upper outer surface of the outer wall portion 45 that define the outer thickness of the second protrusion 58 are located at the same radial position.

[0088] Thus, the first projection 57 and the second projection 58 have the same thickness dimension, and their inner and outer positions coincide. Therefore, as already mentioned, the diaphragm 15 can be assembled to the housing 14 in a reversible manner.

[0089] [Manufacturing Method by Two-Color Molding] A method for manufacturing the diaphragm 15 by two-color molding will be explained with reference to the flowchart in Figure 8 and the schematic cross-sectional view in Figure 9. Figure 9 shows the portion corresponding to the vicinity of the peripheral edge 55 in Figure 6A. Furthermore, the manufacturing method described here is just one example of a preferred method for manufacturing the diaphragm 15, and the manufacturing method of the diaphragm 15 is not limited to this, and other manufacturing methods may be employed. The manufacturing method of the diaphragm 15 according to this embodiment includes a primary step of molding the support frame 40 and a secondary step of molding the flexible film 50 that follows.

[0090] In the first step (step S1), the support frame 40 is formed using a common mold MC and a primary mold M1. The common mold MC is a mold used in common in this first step and in the second step that follows the first step. The primary mold M1 is a mold used only in the first step. In the first step, the common mold MC and the primary mold M1 are first joined together along a first direction to form a primary cavity C1 inside (see S1-1 in Figure 9). The primary cavity C1 is a space corresponding to the support frame 40, and the primary mold M1 has a primary gate G1 that communicates with this primary cavity C1. The primary gate G1 is provided, for example, at a position corresponding to the upper end of the outer wall portion 45 of the support frame 40.

[0091] Through this primary gate G1, the molten primary material (for example, the first material described above) is injected into the primary cavity C1 at a predetermined pressure, and the primary cavity C1 is filled with the primary material (see S1-2 in Figure 9). After a predetermined time, when the primary material has cooled and hardened, the next secondary process is performed.

[0092] In the secondary process (step S2), the primary mold M1 is first released from the common mold MC along the first direction (see S2-1 in Figure 9). Here, the lower surface of the support frame 40 has multiple notches 46 (see Figure 7C), and the corresponding parts of the common mold MC fit into these notches 46. This ensures a large contact area between the support frame 40 and the common mold MC, making it difficult for the support frame 40 to detach from the common mold MC. Therefore, when releasing the primary mold M1 from the common mold MC, the support frame 40 is held by the common mold MC and prevented from detaching from it.

[0093] Next, after demolding of the primary mold M1, the secondary mold M2 is aligned with the common mold MC that holds the support frame 40 along the first direction, and a secondary cavity C2 is formed inside (see S2-2 in Figure 9). The secondary cavity C2 is a space corresponding to the flexible film 50, and the secondary mold M2 has a secondary gate G2 that communicates with this secondary cavity C2. The secondary gate is provided, for example, at a position corresponding to the top 51a of the film portion 51 of the flexible film 50. The top 51a of the film portion 51 is the central part when the film portion 51 is viewed from above; in other words, it is the position of the rotation center at which the film portion 51 is rotationally symmetrical when viewed from above.

[0094] Through this secondary gate G2, the molten secondary material (for example, the second material described above) is injected into the secondary cavity C2 at a predetermined pressure, and the secondary cavity C2 is filled with the secondary material (see S2-3 in Figure 9). After a predetermined time, when the secondary material has cooled and hardened, the secondary mold M2 is released from the common mold MC, and the common mold MC is released from the molded product (diaphragm 15) (step S3).

[0095] As described above, in the manufacturing method for the diaphragm 15 according to this embodiment, the support frame 40 is formed from a hard primary material in the first step, and the flexible membrane 50 is formed from a soft secondary material in the subsequent second step, thereby integrally molding the support frame 40 and the flexible membrane 50. This prevents the primary molded product formed in the first step from being deformed by the injection pressure of the secondary material in the second step, and enables the diaphragm 15 to be manufactured with high precision.

[0096] Furthermore, in the manufacturing method of the diaphragm 15 according to this embodiment, a plurality of second engaging portions 42 are formed on the support frame 40 in the primary step, and a plurality of second engaged portions 62 are formed on the flange portion 52 in the secondary step. Furthermore, a plurality of first engaged portions 41 are formed on the support frame 40 in the primary step (see S1-2 in Figure 9), and a plurality of first engaging portions 61 are formed on the flange portion 52 in the secondary step (see S2-3 in Figure 9).

[0097] In this way, since the support frame 40 and the flexible film 50 are connected by multiple engaging and engaged portions, the connection strength between the primary-molded support frame 40 and the secondary-molded flexible film 50 can be increased. Furthermore, the improved connection strength increases the design freedom of the gate position in the secondary process, making it possible, for example, to provide a secondary gate G2 for secondary molding at a position away from the primary-molded product. Therefore, the secondary gate G2 can be provided at a more suitable position for improving the quality of the secondary-molded product, the flexible film 50. In this embodiment, since the secondary gate G2 is provided at a position corresponding to the top 51a of the film portion 51, the entire film portion 51, which is made of a thin film, can be molded into a homogeneous film, and an improvement in pressure measurement accuracy can be expected.

[0098] Furthermore, in the above manufacturing method, the molded product formed in the first step is a support frame 40 made of a hard primary material, so this support frame 40 is less likely to deform due to the injection pressure of the secondary material in the second step. Therefore, a diaphragm 15 with high dimensional accuracy can be realized. Moreover, each engaging part and each engaged part is configured to extend in the first direction, which is the direction of movement of the mold for two-color molding. For this reason, complex molding equipment such as a core back mechanism that slides a part of the mold in a direction different from the first direction is unnecessary in two-color molding.

[0099] Furthermore, the support frame 40 is provided with multiple notches 46. This suppresses the occurrence of sink marks, which are shrinkage phenomena that occur when the molten primary material cools in the mold. In addition, bridging portions 47 are provided between adjacent notches 46, and multiple bridging portions 47 are interposed between the inner wall portion 43 and the outer wall portion 45. Therefore, the support frame 40 can maintain a certain strength while being lightened by the notches 46. Moreover, these bridging portions 47 can be used as contact points for the ejector pin when demolding the molded product from the common mold MC after the completion of the secondary process.

[0100] In this embodiment, the first engaged portion 41 and the second engaged portion 42 are formed in the first step, and the first engaged portion 61 and the second engaged portion 41 are formed in the second step, but the embodiment is not limited to this. That is, if the support frame 40 has only the first engaged portion 41 and the flange portion 52 has only the first engaged portion 61, the first engaged portion 41 may be formed in the first step without forming the second engaged portion 42, and the first engaged portion 61 may be formed in the second step without forming the second engaged portion 62. Also, if the support frame 40 has only the second engaged portion 42 and the flange portion 52 has only the second engaged portion 62, the second engaged portion 42 may be formed in the first step without forming the first engaged portion 41, and the second engaged portion 62 may be formed in the second step without forming the first engaged portion 61.

[0101] Furthermore, although the above describes a method for manufacturing the diaphragm 15 in which the support frame 40 is formed in the primary step and the flexible membrane 50 is formed in the secondary step, the method is not limited to this. For example, the diaphragm 15 may be manufactured in the reverse order, by forming a flexible membrane 50 having at least one of an engaging portion and an engaged portion from a soft secondary material in the primary step, and then forming a support frame 40 having at least one of an engaging portion and an engaged portion from a hard primary material in the subsequent secondary step. Also, although Figure 9 shows an example in which the common mold MC, primary mold M1, and secondary mold M2 consist of one mold part, the configuration of each mold is not limited to this. Each mold may be composed of a combination of two or more mold parts.

[0102] (Modification 1) The configuration of the diaphragm 15A according to Modification 1 will be described with reference to Figures 10 to 12. This diaphragm 15A has an anchor portion in the engagement structure between the support frame 40A and the flexible membrane 50A.

[0103] Figure 10A is a perspective view of the diaphragm 15A seen from diagonally above, and Figure 10B is a plan view of the diaphragm 15A. Figure 11A is a perspective view of the flexible membrane 50A, and Figure 11B is a perspective view of the support frame 40A. Figure 12A is a cross-sectional view taken along line C-C in Figure 10B, and Figure 12B is a cross-sectional view taken along line D-D in Figure 10B. Note that parts of the diaphragm 15A that are the same as those of the diaphragm 15 described earlier are denoted by the same reference numerals, and their descriptions are omitted.

[0104] The flexible membrane 50A of the diaphragm 15A has a first engaging portion 61A with a different configuration from the first engaging portion 61 of the diaphragm 15. Specifically, the first engaging portion 61A is convex in shape, extending downward from the lower surface of the upper wall portion 64 of the second flange portion 54, similar to the first engaging portion 61. However, the lower end of the first engaging portion 61A is provided with an inner convex portion 70 extending radially inward from the inner surface and an outer convex portion 71 extending radially outward from the outer surface.

[0105] The inner protrusion 70 has a cross-section that is rectangular in shape in a plane including the vertical and radial directions, and when viewed from above, it forms a long arc shape that extends along the circumferential direction of the diaphragm 15A. Similarly, the outer protrusion 71 has a cross-section that is rectangular in shape in a plane including the vertical and radial directions, and when viewed from above, it forms a long arc shape that extends along the circumferential direction of the diaphragm 15A. The first engaging portion 61A having such inner protrusions 70 and outer protrusions 71 has a cross-sectional shape that is approximately inverted T-shaped.

[0106] Furthermore, the support frame 40A of the diaphragm 15A has a perforated first engaging portion 41A. Similar to the first engaging portion 41 of the diaphragm 15, this first engaging portion 41A is formed as a vertically penetrating hole in the middle wall portion 44 of the support frame 40. Near the lower part of the first engaging portion 41A, an inner recess 72 consisting of a notch is formed in the lower part of the inner wall portion 43, and an outer recess 73 consisting of a notch is also formed in the lower part of the outer wall portion 45. The inner recess 72 has a shape that aligns with the inner convex portion 70 and is a rectangular shape that is elongated in the circumferential direction, and the outer recess 73 also has a shape that aligns with the outer convex portion 71 and is a rectangular shape that is elongated in the circumferential direction.

[0107] In the diaphragm 15A, the first engaging portion 61A fits vertically into the first engaged portion 41A, the inner protrusion 70 fits radially into the inner recess 72, and the outer protrusion 71 fits radially into the outer recess 73. Therefore, the engagement between the inner protrusion 70 and the inner recess 72 constitutes an anchor portion for preventing detachment, and the engagement between the outer protrusion 71 and the outer recess 73 also constitutes an anchor portion for preventing detachment. In addition, in the diaphragm 15A, similar to the diaphragm 15, the second engaging portion 42 of the support frame 40A fits into the second engaged portion 62 of the flexible membrane 50A.

[0108] Furthermore, with the support frame 40A and the flexible membrane 50A connected as described above, the inner end face of the inner protrusion 70 of the flexible membrane 50A is flush with the inner surface of the inner wall portion 43 of the support frame 40A, and the outer end face of the outer protrusion 71 of the flexible membrane 50A is flush with the outer surface of the outer wall portion 45 of the support frame 40A.

[0109] The diaphragm 15A according to this modified example 1 can be used as a component of the pressure measuring chamber 1, similar to the diaphragm 15 according to the embodiment, and can achieve the same effects and advantages as described in the embodiment.

[0110] In this modified example 1, the inner recess 72 is shown as having a configuration that penetrates the inner layer wall 43 radially (inward / outward), but it is not limited to this, and the recess may not penetrate inward. Similarly, the outer recess 73 is shown as having a configuration that penetrates the outer layer wall 45 radially, but it is not limited to this, and the recess may not penetrate outward. Also, although the four first engaging portions 61A and the four first engaged portions 41A are shown as having the same configuration, it is not limited to this. Some of the four may be first engaging portions 61A and the rest may be first engaging portions 61. Correspondingly, some of the four may be first engaged portions 41A and the rest may be first engaged portions 41.

[0111] Furthermore, in the two-color molding of the diaphragm 15A having an anchor portion as described above, in the first step, in addition to the common mold and the primary mold, a sliding mold corresponding to the inner recess 72 and the outer recess 73 of the support frame 40A should be prepared.

[0112] (Modification 2) The configuration of the diaphragm 15B according to Modification 2 will be described with reference to Figures 13 to 15. Compared to the diaphragm 15 according to the embodiment, this diaphragm 15B has an anchor portion, while the second engaging portion 42 and the second engaged portion 62 are omitted.

[0113] Figure 13A is a perspective view of the diaphragm 15B seen from diagonally above, and Figure 13B is a plan view of the diaphragm 15B. Figure 14A is a perspective view of the flexible membrane 50B, and Figure 14B is a perspective view of the support frame 40B. Figure 15A is a cross-sectional view taken along line E-E in Figure 13B, and Figure 15B is a cross-sectional view taken along line F-F in Figure 13B. Note that parts of the diaphragm 15B that are the same as those of the diaphragm 15 described earlier are denoted by the same reference numerals, and their descriptions are omitted.

[0114] Unlike the flexible membrane 50 of the diaphragm 15, the flexible membrane 50B of the diaphragm 15B does not have a second engaged portion 62, and the upper surface of the upper wall portion 64 of the second flange portion 54 is a flat surface flush with the entire surface. On the other hand, the flexible membrane 50B has a first engaged portion 61B with a different configuration from the first engaged portion 61 of the flexible membrane 50. Specifically, this first engaged portion 61B is convex in shape extending downward from the lower surface of the upper wall portion 64, while an outward convex portion 80 extending radially outward from the outer surface is provided in the middle of the first engaged portion 61B in the vertical direction.

[0115] Furthermore, unlike the support frame 40 of the diaphragm 15, the support frame 40B of the diaphragm 15B does not have a convex second engaging portion 42 extending upward from the intermediate wall portion 44. The upper surface of the intermediate wall portion 44 is a flat surface that is flush with the surface overall, and is located between the upper surface of the inner wall portion 43 located below and the upper surface of the outer wall portion 45 located above.

[0116] Furthermore, the support frame 40B has a perforated first engaging portion 41B. Similar to the first engaging portion 41 of the diaphragm 15, this first engaging portion 41B is formed as a vertically penetrating through-hole in the middle wall portion 44 of the support frame 40. In addition, an outer hole 81 is formed in the vertically intermediate portion of the first engaging portion 41B, penetrating the outer wall portion 45 in the radial direction.

[0117] The outer projection 80 has a cross-section that is rectangular in shape in the plane including the vertical and radial directions, and when viewed from above, it forms a long arc shape that extends along the circumferential direction of the diaphragm 15B. The outer hole 81 has a shape that matches the outer projection 80, and specifically, it forms a long rectangle shape in the circumferential direction.

[0118] In the diaphragm 15B, the first engaging portion 61B fits vertically into the first engaged portion 41B, while the outer projection 80 fits radially into the outer hole 81. Therefore, the engagement between the outer projection 80 and the outer hole 81 constitutes an anchor portion for preventing detachment. The support frame 40B of the diaphragm 15B has a notch 46 and a bridging portion 47 on its lower surface, similar to the support frame 40 of the diaphragm 15.

[0119] The diaphragm 15B according to this modified example 2 can be used as a component of the pressure measuring chamber 1, just like the diaphragm 15 according to the embodiment, and can achieve the same effects and advantages as described in the embodiment.

[0120] In this modified example 2, the outer hole 81 is shown as a configuration that penetrates the outer layer wall 45 radially, but it is not limited to this, and it may also be a recess that does not penetrate to the outside. Also, although the four first engaging portions 61B and the four first engaged portions 41B are shown as having the same configuration, it is not limited to this. Some of the four may be first engaging portions 61B and the rest may be first engaging portions 61. Correspondingly, some of the four may be first engaged portions 41B and the rest may be first engaged portions 41.

[0121] Furthermore, in the two-color molding of the diaphragm 15B having an anchor portion as described above, in the first step, in addition to the common mold and the primary mold, a slide mold corresponding to the outer hole 81 of the support frame 40B should be prepared.

[0122] This disclosure can be suitably applied to a diaphragm-type pressure measuring chamber for measuring the pressure of blood flowing through a blood circuit, and a method for manufacturing a diaphragm used therein.

[0123] 1 Pressure measuring chamber 11 First case 12 Second case 13 Chamber space 13a First chamber 13b Second chamber 14 Housing 15 Diaphragm 16 Housing space 23 First circumference 27 First groove (engagement groove, receiving groove) 33 Second circumference 37 Second groove (engagement groove, receiving groove) 40 Support frame 41 First engaged part 42 Second engaged part 46 Notch 47 Bridged part 50 Flexible membrane 51 Membrane part 52 Flange part 53 First flange part (clamped part) 54 Second flange part 55 Peripheral edge 56 Outer peripheral edge (outer projection) 57 First projection 58 Second projection 61 First engaging part 62 Second engaged part

Claims

1. A diaphragm-type pressure measuring chamber for measuring the pressure of blood in a blood circuit, comprising: a first case having a first circumferential portion; a second case having a second circumferential portion and connected to the first case to form a chamber space between the first case and the second case; and a diaphragm provided between the first case and the second case in a first direction, dividing the chamber space into a first chamber between the first case and the second case and a second chamber between the second case, wherein the diaphragm comprises: an annular support frame made of a rigid first material and located between the first and second circumferential portions; a membrane portion located between the first and second chambers and having a three-dimensional shape in which at least a part is convex in the first direction; and a flange portion provided around the membrane portion and engaging with the support frame, and comprising a flexible membrane made of a second material softer than the first material, wherein at least one of the flange portion and the support frame is provided with a plurality of convex engaging portions extending in the first direction along the circumferential direction, and the other is provided with a plurality of concave or perforated engaging portions into which the engaging portions fit, A diaphragm-type pressure measuring chamber.

2. The pressure measuring chamber according to claim 1, wherein the diaphragm is provided with the engagement portion on the flange portion and the supported frame is provided with the engaged portion, and the flange portion is provided with the engaged portion and the supported frame is provided with the engagement portion.

3. The pressure measuring chamber according to claim 1 or 2, wherein the peripheral edge of the diaphragm, located on the outer circumference side of the membrane portion, has the support frames positioned at both ends in the first direction.

4. The pressure measuring chamber according to any one of claims 1 to 3, wherein one or the other surface of the support frame in the first direction is provided with a notch that opens on the one or the other surface in the first direction.

5. The pressure measuring chamber according to claim 4, wherein a plurality of the notches are provided in the circumferential direction of the support frame, and a bridging portion is provided between two adjacent notches.

6. The pressure measuring chamber according to any one of claims 1 to 5, wherein the diaphragm has a front surface and a back surface, and is reversible so that it can be assembled to the first case and the second case with the front surface facing either one side in the first direction or the other side.

7. The pressure measuring chamber according to any one of claims 1 to 6, wherein the diaphragm is manufactured by integral molding by injection molding, and is formed by a primary step of forming the support frame and a secondary step of integrally forming the flexible membrane with respect to the support frame.

8. A diaphragm-type pressure measuring chamber for measuring the pressure of blood in a blood circuit, comprising: a first case having a first circumferential portion; a second case having a second circumferential portion and connected to the first case to form a chamber space between the first case and the second case; and a diaphragm provided between the first case and the second case in a first direction, having a front surface and a back surface, and dividing the chamber space into a first chamber between the first case and the second case and a second chamber between the second case, wherein the diaphragm comprises: an annular support frame made of a rigid first material and located between the first circumferential portion and the second circumferential portion; a membrane portion located between the first chamber and the second chamber and having a three-dimensional shape in which at least a part is convex in the first direction; and a flange portion provided around the membrane portion and engaging with the support frame, and a flexible membrane made of a second material softer than the first material, The peripheral edge of the diaphragm located on the outer periphery of the membrane portion has a clamped portion sandwiched between the first and second periphery portions, and an annular outer peripheral projection portion that includes the support frame and is on the outer periphery of the clamped portion and protrudes on both sides in the first direction, the first case and the second case, in the assembled state, have an annular housing space in which the outer peripheral projection portion is housed, the housing space is partitioned by a first groove formed in the first periphery portion and a second groove formed in the second periphery portion, one of the first groove and the second groove is an engagement groove portion that can engage with either one side in the first direction or the other side in the first direction of the outer peripheral projection portion, and the other of the first groove and the second groove is a receiving groove portion that can receive either one side in the first direction or the other side in the first direction of the outer peripheral projection portion. A diaphragm-type pressure measuring chamber, wherein the diaphragm is reversible, with the outer peripheral projection housed within the housing space whether the surface faces one side in a first direction or the other, and can be assembled reversibly into the first case and the second case.

9. A method for manufacturing a diaphragm for a pressure measuring chamber by two-color molding, comprising: an annular support frame made of a hard primary material; and a flexible membrane made of a softer secondary material, including a dome-shaped membrane portion and a flange portion provided around the membrane portion and engaging with the support frame, the method comprising: a primary step of injecting molten primary material into a primary cavity formed by a common mold and a primary mold to form the support frame; and a secondary step of, with the support frame held in the common mold, releasing the primary mold from the common mold in a first direction, and then injecting molten secondary material into a secondary cavity formed by the common mold and a secondary mold to integrally mold the flexible membrane with respect to the support frame.

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