Pressure detection device

Abstract

This prevents the connecting portion, which is joined to the pressure-receiving diaphragm of the flow path unit, from separating from the pressure-receiving diaphragm. [Solution] A pressure detection device is provided in which a pressure detection unit has a first connecting part which is a magnet, a flow path unit 20 has a resin pressure receiving diaphragm 22 and a second connecting part 23 having a magnetic material 23b, and when the flow path unit 20 is attached to the pressure detection unit, the first connecting part and the second connecting part 23 are arranged in a state where they are attracted to each other by magnetic force, the second connecting part 23 has a resin joining member 23a formed at both ends in the direction along the axis Y2, a first joining surface 23a1 that is joined to the pressure receiving diaphragm 22 and a second joining surface 23a2 that is joined to the magnetic material 23b, the first joining surface 23a1 of the joining member 23a and the pressure receiving diaphragm 22 are joined by an adhesive, and the second joining surface 23a2 of the joining member 23a and the magnetic material 23b are joined by an adhesive.

Description

Technical Field

[0001] The present invention relates to a pressure detection device.

Background Art

[0002] Conventionally, there is known a pressure detection device in which a flow path unit in which a flow path for introducing a fluid is formed is attached to a pressure detection unit, and the pressure of the fluid flowing through the flow path unit is detected by the pressure detection unit (see, for example, Patent Document 1). The pressure detection device disclosed in Patent Document 1 is provided with a first connection portion formed by a magnet on the diaphragm of the pressure detection unit and a second connection portion formed by a magnetic body on the diaphragm of the flow path unit.

[0003] In the pressure detection device disclosed in Patent Document 1, in a state where the flow path unit is attached to the pressure detection unit, the first connection portion and the second connection portion are arranged in a state of being attracted by magnetic force. Therefore, when the pressure of the fluid flowing through the flow path is a negative pressure, the second connection portion is attracted toward the flow path side by the pressure of the fluid, and the first connection portion connected to the second connection portion by magnetic force is attracted toward the flow path side. Thereby, the pressure of the fluid can be detected as a negative pressure by the pressure detection unit.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the pressure detection device disclosed in Patent Document 1, the second connecting portion, which is made of a magnetic material, is joined to the flat surface of the diaphragm of the flow path unit on the pressure detection unit side by an adhesive. However, because the second connecting portion is joined to a flat surface, changes in the diaphragm's deformation due to changes in fluid pressure cause changes in stress at the joint between the flat surface and the second connecting portion. As the diaphragm repeatedly deforms, the joint deteriorates, causing the second connecting portion to separate from the diaphragm, making it impossible to properly detect the fluid pressure.

[0006] The present invention has been made in view of these circumstances, and aims to prevent the connecting portion joined to the pressure-receiving diaphragm of the flow path unit from separating from the pressure-receiving diaphragm in a pressure detection device comprising a flow path unit and a pressure detection unit. [Means for solving the problem]

[0007] To solve the above problems, the present invention employs the following means. A pressure detection device according to a first aspect of the present invention comprises a pressure detection unit for detecting pressure transmitted to a pressure detection unit, a flow path unit having a flow path formed therein for flowing fluid, and a mounting mechanism for detachably attaching the flow path unit to the pressure detection unit, wherein the pressure detection unit has a pressure sensor having the pressure detection unit and a first connecting portion joined to the pressure detection unit, the flow path unit has a resin pressure receiving portion that is displaced by the pressure of the fluid flowing through the flow path and a second connecting portion joined to the pressure receiving portion, either the first connecting portion or the second connecting portion has a magnet, and the other of the first connecting portion or the second connecting portion has a magnet or magnetic material, and the flow is detachably attached to the pressure detection unit by the mounting mechanism With the road unit attached to the pressure detection unit, the first connecting portion and the second connecting portion are arranged in a state where they are attracted to each other by magnetic force, the pressure receiving portion is formed in a circular shape in plan view and is formed in a plate shape from the center to the end, the second connecting portion is formed in a cylindrical shape extending along the axis and has a resin connecting member formed at both ends in the direction along the axis, having a first connecting surface that is joined to the pressure receiving portion and a second connecting surface that is joined to the magnet or the magnetic material, the first connecting surface of the connecting member and the pressure receiving portion are joined with adhesive in a predetermined range surrounding the center position, and the second connecting surface of the connecting member and the magnet or the magnetic material are joined with adhesive.

[0008] According to the pressure detection device of the first aspect of the present invention, when the flow path unit is attached to the pressure detection unit by the mounting mechanism, the first connecting part joined to the pressure detection section and the second connecting part joined to the pressure receiving section are arranged in a state where they are attracted to each other by magnetic force. Therefore, when the pressure of the fluid flowing through the flow path is positive, the pressure of the fluid pulls the second connecting part joined to the pressure receiving section away from the flow path side, and the second connecting part pushes the first connecting part toward the pressure detection section. As a result, the pressure of the fluid is detected as positive pressure by the pressure detection section.

[0009] Furthermore, when the pressure of the fluid flowing through the channel is negative, the fluid pressure pulls the second connecting part, which is joined to the pressure receiving part, towards the channel, and the second connecting part pulls the first connecting part, which is connected by magnetic force, towards the channel. As a result, the fluid pressure is detected as negative pressure by the pressure detection part. Thus, according to the pressure detection device of the first aspect of the present invention, the fluid pressure can be accurately detected whether the fluid pressure is positive or negative, while improving the speed and safety of the operation of changing the fluid introduced into the channel.

[0010] Furthermore, according to the pressure detection device of the first aspect of the present invention, the first joining surface of the joining member joined to the pressure receiving part and the pressure receiving part are joined by an adhesive within a predetermined range surrounding the center position. Since the joining member and the pressure receiving part are each made of resin, the joining member and the pressure receiving part are joined more firmly than when a metal material such as a magnet or magnetic material is joined to the pressure receiving part with an adhesive. Therefore, even if a change in stress occurs at the joint between the second connecting part and the pressure receiving part, the state in which the second connecting part is firmly joined to the pressure receiving part is maintained, and the second connecting part joined to the pressure receiving part of the flow path unit is prevented from separating from the pressure receiving part.

[0011] Furthermore, according to the pressure detection device of the first aspect of the present invention, the second joining surface of the joining member and the magnet or magnetic material, which is a metallic material, are joined by an adhesive. Since the joining member is made of resin and the magnet or magnetic material is made of metal, the bonding strength between the second joining surface and the metallic material is lower compared to when resin members are joined together. On the other hand, the metallic material is not directly joined to the pressure receiving part, and the displacement of the second joining surface is small even when subjected to fluid pressure. Therefore, the state in which the second joining surface and the magnet or magnetic material, which is a metallic material, are joined by the adhesive can be appropriately maintained.

[0012] A pressure detection device according to a second aspect of the present invention further comprises the following configuration in the first aspect: the joining member has a communication hole that connects the first joining surface and the second joining surface and is located at the central position.

[0013] According to the pressure detection device of the second aspect of the present invention, excess adhesive applied to the first and second joining surfaces can be contained in the communication hole, thereby ensuring that the first and second joining surfaces are joined with an appropriate amount of adhesive.

[0014] A pressure detection device according to a third aspect of the present invention further comprises the following configuration in the first aspect. That is, the first outer diameter when the first joint surface is viewed in plan is set to be at least 1 / 3 and at least 1 / 2 times the second outer diameter when the region of the pressure-receiving part in contact with the fluid is viewed in plan.

[0015] According to the pressure detection device of the third aspect of the present invention, by making the first outer diameter of the first joint surface 1 / 3 or more of the second outer diameter of the region in contact with the fluid of the pressure-receiving part, the size of the first outer diameter of the first joint surface joined to the pressure-receiving part can be sufficiently secured, and the attractive force that causes the second connecting part and the first connecting part to be attracted by magnetic force can be sufficiently secured. Furthermore, by making the first outer diameter of the first joint surface 1 / 2 or less of the second outer diameter of the region in contact with the fluid of the pressure-receiving part, it is possible to prevent the first outer diameter of the first joint surface from becoming excessively large, which would impair the ability of the pressure-receiving part to follow pressure changes.

[0016] A pressure detection device according to a fourth aspect of the present invention further comprises the following configuration in the first aspect: the outer diameter of the first connecting portion centered on the axis perpendicular to the pressure receiving portion is larger than the outer diameter of the second connecting portion centered on the axis.

[0017] According to the pressure detection device of the fourth aspect of the present invention, the outer diameter of the first connecting portion can be sufficiently secured, and sufficient attractive force can be secured between the second connecting portion and the first connecting portion by magnetic force.

[0018] The pressure detection device according to the fifth aspect of the present invention further includes the following configuration in any one of the first aspect to the fourth aspect. That is, the first joint surface is a flat surface disposed on a plane orthogonal to the axis, the second joint surface is a stepped surface with a concave portion formed at the center position, the magnet or the magnetic body joined to the joint member has a convex portion formed at the center position, and the joint member is joined to the magnet or the magnetic body with the convex portion inserted into the concave portion.

[0019] According to the pressure detection device according to the fifth aspect of the present invention, since the joint member is joined to the magnet or the magnetic body with the convex portion inserted into the concave portion, when joining the joint member to the magnet or the magnetic body, it is possible to appropriately prevent these members from shifting in the radial direction orthogonal to the axis, and the joining strength of these members can be increased.

Effects of the Invention

[0020] According to the present invention, in a pressure detection device including a flow path unit and a pressure detection unit, it is possible to prevent the connection portion joined to the pressure receiving diaphragm of the flow path unit from separating from the pressure receiving diaphragm.

Brief Description of the Drawings

[0021] [Figure 1] It is a front view showing a pressure detection device according to an embodiment of the present invention. [Figure 2] It is a view showing a state where the flow path unit is removed from the pressure detection device shown in FIG. 1. <0000​​​​​​​​​​​​​​​ [Figure 8] This is a cross-sectional view showing the state before the bonding member and the magnetic material are bonded together. [Figure 9] This is a cross-sectional view showing the joining part installed on the joining jig. [Figure 10] This is a cross-sectional view showing the condition when ultraviolet light is irradiated onto the connecting portion and the pressure-receiving diaphragm. [Figure 11] This is a cross-sectional view showing the pressure-receiving diaphragm attached to the main flow channel body. [Figure 12] This is a cross-sectional view showing the flow path body with a nut attached. [Figure 13] This is a cross-sectional view showing the deformed state of the pressure-receiving diaphragm of the flow path unit in this embodiment. [Figure 14] This is a cross-sectional view showing the deformed state of the pressure-receiving diaphragm of the flow channel unit in the comparative example. [Modes for carrying out the invention]

[0022] Hereinafter, a pressure detection device 100 according to one embodiment of the present invention will be described with reference to the drawings. Figure 1 is a front view showing the pressure detection device 100 according to one embodiment of the present invention. Figure 2 is a diagram showing the pressure detection device 100 shown in Figure 1 with the flow path unit 20 removed. Figure 3 is a cross-sectional view taken along the line AA showing the pressure detection device 100 shown in Figure 1 with the flow path unit 20 removed.

[0023] As shown in Figure 1, the pressure detection device 100 of this embodiment includes a pressure detection unit 10 attached to the mounting surface S with fastening bolts (not shown), a flow path unit 20 having a flow path 21 formed inside for fluid circulation, and a nut 30 (mounting mechanism) for detachably attaching the flow path unit 20 to the pressure detection unit 10.

[0024] As shown in Figure 1, the pressure detection unit 10 is mounted on the mounting surface S, and the flow path unit 20 is attached to the pressure detection unit 10 by a nut 30. The pressure detection device 100 is mounted on the mounting surface S with the flow path unit 20 attached to the pressure detection unit 10 by the nut 30, forming an integrated unit.

[0025] As shown in Figure 3, an inlet pipe (not shown) is attached to the inlet 21a of the flow path unit 20 to allow fluid to flow into the inlet 21a, and an outlet pipe (not shown) is attached to the outlet 21b of the flow path unit 20 to allow fluid to flow out of the outlet 21b. The pressure of the fluid flowing through the flow path 21 from the inlet 21a to the outlet 21b is detected by the pressure detection unit 10. Here, the fluid is a liquid such as blood or dialysate.

[0026] As shown in Figure 3, the pressure detection unit 10 includes a main body 13 that is attached to the mounting surface S. As shown in Figures 2 and 3, a cable 19 is attached to the main body 13 of the pressure detection unit 10 via a cable mounting nut 19a, which electrically connects an internally located pressure sensor 12 to an external control device (not shown).

[0027] Next, the pressure detection unit 10 will be described in detail with reference to Figures 1 to 3. The pressure detection unit 10 shown in Figures 1 to 3 is a device that detects the pressure transmitted to the diaphragm (pressure detection part) 12a. The pressure detection unit 10 comprises a connecting part (first connecting part) 11, a pressure sensor 12, a main body part 13 in which the pressure sensor 12 is placed, a sensor holding part 14 that holds the pressure sensor 12 in the main body part 13, a sensor board 15 for transmitting power and electrical signals between the pressure sensor 12 and the cable 19, and a zero-point adjustment switch 16 for adjusting the zero point of the pressure sensor 12.

[0028] The connecting portion 11 is a permanent magnet formed in a cylindrical shape along the axis Y1, and is made of, for example, neodymium. The connecting portion 11 is joined to the second surface 12aB of the diaphragm 12a of the pressure sensor 12 by an adhesive (for example, an epoxy resin adhesive). As shown in Figure 3, the end face of the connecting portion 11 that is joined to the diaphragm 12a is formed to have a planar shape that is positioned on a plane perpendicular to the axis Y1. The connecting portion 11 attracts the magnetic connecting portion (second connecting portion) 23, which has a magnetic material, by the magnetic force of the permanent magnet and maintains contact with it. The connecting portion 23 of the flow path unit 20 will be described later.

[0029] In the above description, the connecting portion 11 is assumed to have a permanent magnet and the connecting portion 23 is assumed to have a magnetic material, but other configurations are also possible. For example, both the connecting portion 11 and the connecting portion 23 may have permanent magnets. Alternatively, the connecting portion 11 may have a magnetic material and the connecting portion 23 may have a permanent magnet. As described above, in this embodiment, the pressure detection device 100 has either the connecting portion 11 or the connecting portion 23 having a magnet, and the other of the connecting portion 11 or the connecting portion 23 having a magnet or a magnetic material. Below, an example in which the connecting portion 11 has a permanent magnet and the connecting portion 23 has a magnetic material will be described.

[0030] As shown in Figure 3, the pressure sensor 12 includes a diaphragm 12a formed in the form of a thin film from a corrosion-resistant material (for example, sapphire), a strain resistance portion 12b joined to the second surface 12aB of the diaphragm 12a, and a base portion 12c that holds the diaphragm 12a.

[0031] The pressure sensor 12 is a strain-type sensor that outputs a pressure signal corresponding to the change in the resistance value of a strain resistance section 12b, which deforms in response to the pressure transmitted from the connecting section 23 to the first surface 12aA of the diaphragm 12a. The base section 12c has a through hole that communicates with the diaphragm 12a, and the second surface 12aB of the diaphragm 12a is maintained at atmospheric pressure. Therefore, the pressure sensor 12 is a sensor that detects gauge pressure based on atmospheric pressure. As shown in Figure 2, when the flow path unit 20 is not attached to the pressure detection unit 10, the diaphragm 12a of the pressure sensor 12 is exposed to the outside.

[0032] The sensor holder 14 is a cylindrical member formed around the axis Y1. Since the inner diameter of the upper end of the sensor holder 14 is smaller than the outer diameter of the pressure sensor 12, the pressure sensor 12 can be held in place so that it does not come out upwards. The sensor holder 14 holds the diaphragm 12a, which is bonded to the base portion 12c with adhesive (adhesive glass).

[0033] The sensor board 15 includes an amplification circuit (not shown) that amplifies the pressure signal output by the pressure sensor 12, an interface circuit that transmits the amplified pressure signal to the pressure signal line (not shown) of the cable 19, a power supply circuit (not shown) that transmits the power supply voltage supplied from the outside via the cable 19 to the pressure sensor 12, and a zero-point adjustment circuit (not shown) that performs zero-point adjustment when the zero-point adjustment switch 16 is pressed. The zero-point adjustment circuit is a circuit that adjusts the pressure signal output by the pressure sensor 12 at that time to set it as a reference value (for example, zero) when the zero-point adjustment switch 16 is pressed.

[0034] Next, the flow path unit 20 will be described in detail with reference to Figures 3 to 6. Figure 4 is a bottom view of the flow path unit 20 shown in Figure 3. Figure 5 is a cross-sectional view taken along the AA line of the pressure detection device 100 shown in Figure 1. Figure 6 is a partially enlarged view of the flow path unit 20 shown in Figure 5.

[0035] As shown in Figure 3, the flow path unit 20 comprises a flow path body 21A having a flow path 21 formed inside that allows fluid to flow in a flow direction along axis X from inlet 21a to outlet 21b, a pressure-receiving diaphragm 22 that is displaced by receiving the pressure of the fluid flowing through the flow path 21 on its first surface 22a, and a connecting portion (second connecting portion) 23 joined to the second surface 22b of the pressure-receiving diaphragm 22.

[0036] The pressure-receiving diaphragm 22 is a component formed in the form of a thin film from a corrosion-resistant resin material (for example, polycarbonate). The pressure-receiving diaphragm 22 is a component formed in a circular shape in plan view with axis Y2 as its central axis, and its outer edge is joined to the flow path 21 by adhesion or welding. Because the pressure-receiving diaphragm 22 is formed in the form of a thin film, it deforms in the direction along axis Y2 due to the pressure of the fluid flowing through the flow path 21. As shown in Figure 6, the pressure-receiving diaphragm 22 is formed in the form of a plate with a constant thickness t1 from the central position P0 through which axis Y2 passes to the end.

[0037] The connecting portion 23 is a cylindrical member formed along an axis Y2 perpendicular to the pressure-receiving diaphragm 22. As shown in Figure 4, the connecting portion 23 is formed in a circular shape in plan view. As shown in Figure 5, the connecting portion 23 is positioned in a state where it is attracted by the magnetic force of the connecting portion 11, which is a permanent magnet, when the flow path unit 20 is attached to the pressure detection unit 10 by a nut 30. As shown in Figure 6, the connecting portion 23 has a joining member 23a and a magnetic material 23b.

[0038] The joining member 23a is a resin member (for example, made of polyvinyl chloride (PVC)) having a first joining surface 23a1 that is joined to the pressure-receiving diaphragm 22 and a second joining surface 23a2 that is joined to the magnetic material 23b, formed at both ends in the direction along the axis Y2. The magnetic material 23b is made of iron material such as S45C as specified in JIS standards.

[0039] The first joining surface 23a1 of the joining member 23a and the pressure-receiving diaphragm 22 are joined by adhesive within a first outer diameter D1 area surrounding the central position P0. Furthermore, the second joining surface 23a2 of the joining member 23a and the magnetic material 23b are joined by adhesive within a first outer diameter D1 area surrounding the central position P0.

[0040] The joining member 23a has a communication hole 23a3 that connects the first joining surface 23a1 and the second joining surface 23a2 and is located at the center position P0. The communication hole 23a3 can accommodate excess adhesive applied to the first joining surface 23a1 and the second joining surface 23a2, allowing the first joining surface 23a1 and the second joining surface 23a2 to be joined with an appropriate amount of adhesive.

[0041] As shown in Figures 4 and 6, the outer diameter of the first joint surface 23a1 viewed from above is the first outer diameter D1, and the outer diameter of the area of ​​the pressure-receiving diaphragm 22 in contact with the fluid viewed from above is the second outer diameter D2. The first outer diameter D1 is set to be at least 1 / 3 and at least 1 / 2 the second outer diameter D2.

[0042] A chamfered surface 23b1 is formed at the end of the magnetic material 23b along its axis Y2. The chamfered surface 23b1 is a chamfered portion formed in an annular shape in the circumferential direction around the axis Y2 at the end in the radial direction RD perpendicular to the axis Y2.

[0043] As shown in Figure 5, when the flow path unit 20 is attached to the pressure detection unit 10, the connecting portion 23 of the flow path unit 20 is in contact with the first surface 12aA of the diaphragm 12a of the pressure detection unit 10. The connecting portion 23 transmits the pressure of the fluid flowing through the flow path 21 to the diaphragm 12a.

[0044] As shown in Figure 5, when the flow path unit 20 is attached to the pressure detection unit 10, axes Y1 and Y2 are positioned at the same location in the radial direction RD. As shown in Figure 5, the third outer diameter D3 of the connecting portion 11 centered on axis Y1 is larger than the first outer diameter D1 of the connecting portion 23 centered on axis Y2. By ensuring that the third outer diameter D3 of the connecting portion 11 is sufficiently larger than the first outer diameter D1 of the connecting portion 23, sufficient magnetic attraction between the connecting portion 23 and the connecting portion 11 can be ensured.

[0045] Next, the structure for attaching the flow path unit 20 to the pressure detection unit 10 using a nut 30 will be described. As shown in Figure 3, an annular groove 22d extending around axis Y2 is formed on the outer circumferential surface of the lower end of the flow path unit 20. On the other hand, an annular projection 30b extending around axis Y2 is formed on the inner circumferential surface of the nut 30. The nut 30, which is made of an elastically deformable material (for example, a resin material), is pushed toward the annular groove 22d, causing the annular projection 30b to engage with the annular groove 22d.

[0046] As shown in Figure 3, when the annular projection 30b is engaged with the annular groove 22d, a small gap is provided between the outer surface of the annular projection 30b and the inner surface of the annular groove 22d. Therefore, the nut 30 can rotate relative to the axis Y2 while attached to the pressure detection unit 10. This allows the operator to rotate the nut 30 around the axis Y2 while the pressure detection unit 10 is fixed to the installation surface S.

[0047] As shown in Figure 3, the nut 30 is an annular member with a female thread 30a extending around the axis Y2 formed on its inner surface. The nut 30 is a mechanism for detachably attaching the flow path unit 20 to the pressure detection unit 10 by fastening the female thread 30a to the male thread 17 formed on the pressure detection unit 10, or by releasing the fastening.

[0048] The operator grips the flow path unit 20 and rotates the nut 30 around axis Y1 in the fastening direction (indicated as "LOCK" in Figures 1 and 2), thereby fastening the female thread 30a of the nut 30 to the male thread 17 of the pressure detection unit 10. By fastening the female thread 30a of the nut 30 to the male thread 17 of the pressure detection unit 10, the connecting portion 23 gradually approaches the first surface 12aA of the diaphragm 12a and eventually contacts the first surface 12aA of the diaphragm 12a, resulting in the state shown in Figure 5.

[0049] Next, a method for manufacturing a pressure detection device 100 according to one embodiment of the present invention will be described. Figure 7 is a flowchart of the method for manufacturing the pressure detection device 100. Figure 8 is a cross-sectional view showing the state before bonding the joining member 23a and the magnetic material 23b. Figure 9 is a cross-sectional view showing the state in which the connecting part 23 is installed on the joining jig 200. Figure 10 is a cross-sectional view showing the state in which ultraviolet light is irradiated onto the connecting part 23 and the pressure receiving diaphragm 22.

[0050] In step S101, the worker adheres the joining member 23a and the magnetic material 23b together. As shown in Figure 8, the first joining surface 23a1 of the joining member 23a is a flat surface positioned on a plane perpendicular to the axis Y2. The second joining surface 23a2 of the joining member 23a is a stepped surface with a recess 23a2A formed at the center of the radial direction RD.

[0051] In the magnetic material 23b, a protrusion 23b2 is formed at the center of the radial direction RD. The outer diameter D5 of the protrusion 23b2 is set to be slightly smaller than the inner diameter D4 of the recess 23a2A of the joining member 23a. The worker applies adhesive AD to the recess 23a2A of the second joining surface 23a2 of the joining member 23a, and inserts the protrusion 23b2 of the magnetic material 23b into the recess 23a2A of the joining member 23a to bond the joining member 23a and the magnetic material 23b. Adhesive AD is, for example, an ultraviolet-curing adhesive.

[0052] In step S102, the worker adheres the pressure-receiving diaphragm 22 to the connecting portion 23. As shown in Figure 9, the joining jig 200 has a recess 210 for positioning the connecting portion 23. The worker grasps the connecting portion 23 and places it in the recess 210 of the joining jig 200. Then, the worker applies adhesive AD to the first joining surface 23a1 of the joining member 23a. Finally, with the center position of the pressure-receiving diaphragm 22 and the center position of the connecting portion 23 aligned, the worker moves the pressure-receiving diaphragm 22 to adhere to the connecting portion 23.

[0053] In step S103, the worker performs a curing treatment of the adhesive AD so that the joining member 23a and the magnetic material 23b of the connecting portion 23 are joined, and the joining member 23a and the pressure-receiving diaphragm 22 are joined. As shown in Figure 10, the worker positions the glass plate 300, which has an outer diameter larger than that of the connecting portion 23, so that it is in contact with the center of the pressure-receiving diaphragm 22. The worker also places a holding member 400 on the glass plate 300 to apply a load to maintain the state in which the glass plate 300 is in contact with the pressure-receiving diaphragm 22.

[0054] The operator operates an irradiation device (not shown) that irradiates ultraviolet light from above the glass plate 300 towards the center of the pressure-receiving diaphragm 22 in the state shown in Figure 10, irradiating the center of the pressure-receiving diaphragm 22 with ultraviolet light for a predetermined time. The adhesive AD applied between the joining member 23a and the magnetic material 23b of the connecting portion 23, and the adhesive AD applied between the joining member 23a and the pressure-receiving diaphragm 22, harden due to the ultraviolet light. As a result, the joining member 23a and the magnetic material 23b of the connecting portion 23 are joined, and the joining member 23a and the pressure-receiving diaphragm 22 are joined.

[0055] In step S104, the worker removes the pressure-receiving diaphragm 22 from the joining jig 200 and welds the entire circumference of the end of the pressure-receiving diaphragm 22 to the flow channel body 21A, resulting in the state shown in Figure 11. Figure 11 is a cross-sectional view showing the state in which the pressure-receiving diaphragm 22 has been joined to the flow channel body 21A. For welding the pressure-receiving diaphragm 22 and the flow channel body 21A, an ultrasonic welding device (not shown) is used, for example, which vibrates the pressure-receiving diaphragm 22 with ultrasonic waves to generate frictional heat at the interface between the pressure-receiving diaphragm 22 and the flow channel body 21A.

[0056] In step S105, the worker attaches the nut 30 to the flow channel body 21A. The worker pushes the nut 30 toward the annular groove 22d, partially elastically deforming the flow channel body 21A so that the annular projection 30b engages with the annular groove 22d, resulting in the state shown in Figure 12. Figure 12 is a cross-sectional view showing the state in which the nut 30 is attached to the flow channel body 21A.

[0057] Here, with reference to Figures 13 and 14, the connection state between the connecting portion 23 and the pressure-receiving diaphragm 22 when the pressure-receiving diaphragm 22 is deformed will be described. Figure 13 is a cross-sectional view showing the deformed state of the pressure-receiving diaphragm 22 of the flow path unit 20 of this embodiment. Figure 14 is a cross-sectional view showing the deformed state of the pressure-receiving diaphragm 22C of the flow path unit of a comparative example.

[0058] As shown in Figure 13, the resin pressure-receiving diaphragm 22 of this embodiment is bonded to the resin joining member 23a with adhesive AD, so it is bonded more firmly to the joining member 23a than when it is bonded to a metal material with adhesive AD. Therefore, even when the pressure-receiving diaphragm 22 is deformed, the state in which the pressure-receiving diaphragm 22 and the connecting part 23 are firmly bonded is maintained.

[0059] On the other hand, as shown in Figure 14, the resin pressure-receiving diaphragm 22C of the comparative example is joined to the metal connecting portion 23C with adhesive AD. Therefore, the bonding strength to the connecting portion 23C is lower compared to when the resin connecting member 23a is joined with adhesive AD. Consequently, if the pressure-receiving diaphragm 22C is repeatedly deformed, the bonding force at the contact point between the pressure-receiving diaphragm 22C and the connecting portion 23C tends to decrease.

[0060] The operation and effects of the pressure detection device 100 of this embodiment, as described above, will now be explained. In the pressure detection device 100 of this embodiment, when the flow path unit 20 is attached to the pressure detection unit 10 by the nut 30, the connecting portion 11 joined to the diaphragm 12a and the connecting portion 23 joined to the pressure-receiving diaphragm 22 are positioned in a state where they are attracted to each other by magnetic force. Therefore, when the pressure of the fluid flowing through the flow path 21 is positive, the fluid pressure pulls the connecting portion 23 joined to the pressure-receiving diaphragm 22 away from the flow path 21 side, and the connecting portion 23 pushes the connecting portion 11 toward the diaphragm 12a. As a result, the fluid pressure is detected as positive pressure by the diaphragm 12a.

[0061] Furthermore, when the pressure of the fluid flowing through the channel 21 is negative, the fluid pressure pulls the connecting portion 23, which is joined to the pressure-receiving diaphragm 22, towards the channel 21, and the connecting portion 23 pulls the magnetically connected connecting portion 11 towards the channel 21. As a result, the fluid pressure is detected as negative pressure by the diaphragm 12a. Thus, the pressure detection device 100 of this embodiment can accurately detect the fluid pressure whether it is positive or negative, while increasing the speed and safety of the operation of changing the fluid introduced into the channel 21.

[0062] Furthermore, according to the pressure detection device 100 of this embodiment, the first joining surface 23a1 of the joining member 23a that is joined to the pressure-receiving diaphragm 22 and the pressure-receiving diaphragm 22 are joined by adhesive AD in a predetermined range surrounding the central position P0. Since the joining member 23a and the pressure-receiving diaphragm 22 are both made of resin, the joining member 23a and the pressure-receiving diaphragm 22 are joined more firmly than when a magnetic material 23b, which is a metallic material, is joined to the pressure-receiving diaphragm 22 with adhesive. Therefore, even if a change in stress occurs at the joint between the connecting part 23 and the pressure-receiving diaphragm 22, the state in which the connecting part 23 is firmly joined to the pressure-receiving diaphragm 22 can be maintained, and the connecting part 23 that is joined to the pressure-receiving diaphragm 22 of the flow path unit 20 can be prevented from separating from the pressure-receiving diaphragm 22.

[0063] Furthermore, according to the pressure detection device 100 of this embodiment, the second joining surface 23a2 of the joining member 23a and the magnetic material 23b, which is a metallic material, are joined by adhesive AD. Since the joining member 23a is made of resin and the magnetic material 23b is made of metal, the bonding strength between the second joining surface 23a2 and the magnetic material 23b is lower compared to when two resin members are joined together. On the other hand, the metallic material is not directly joined to the pressure-receiving diaphragm 22, and the displacement of the second joining surface 23a2 is small even when subjected to fluid pressure. Therefore, the state in which the second joining surface 23a2 and the magnetic material 23b, which is a metallic material, are joined by adhesive AD can be appropriately maintained.

[0064] According to the pressure detection device 100 of this embodiment, any excess adhesive AD applied to the first joining surface 23a1 and the second joining surface 23a2 can be contained in the communication hole 23a3, and the first joining surface 23a1 and the second joining surface 23a2 can be joined with an appropriate amount of adhesive.

[0065] According to the pressure detection device 100 of this embodiment, by making the first outer diameter D1 of the first joint surface 23a1 at least 1 / 3 times the second outer diameter D2 of the area of ​​the pressure-receiving diaphragm 22 that comes into contact with the fluid, the size of the first outer diameter D1 of the first joint surface 23a1 that is joined to the pressure-receiving diaphragm 22 can be sufficiently secured, thereby ensuring sufficient magnetic attraction between the connecting portion 23 and the connecting portion 11. Furthermore, by making the first outer diameter D1 of the first joint surface 23a1 at or below 1 / 2 times the second outer diameter D2 of the area of ​​the pressure-receiving diaphragm 22 that comes into contact with the fluid, it is possible to prevent the first outer diameter D1 of the first joint surface 23a1 from becoming excessively large, which would impair the ability of the pressure-receiving diaphragm 22 to follow pressure changes.

[0066] According to the pressure detection device 100 of this embodiment, by making the third outer diameter D3 of the connecting portion 11 larger than the first outer diameter D1 of the connecting portion 23, the third outer diameter D3 of the connecting portion 11 can be sufficiently secured, thereby ensuring sufficient magnetic attraction between the connecting portion 23 and the connecting portion 11.

[0067] According to the pressure detection device 100 of this embodiment, the joining member 23a is joined to the magnetic material 23b with the protrusion 23b2 inserted into the recess 23a2A. Therefore, when joining the joining member 23a to the magnetic material 23b, it is possible to appropriately prevent these members from shifting in the radial direction RD perpendicular to the axis Y2, thereby increasing the joining strength of these members. [Explanation of Symbols]

[0068] 10 Pressure detection unit 11 Connecting part (1st connecting part) 12 Pressure Sensor 12a Diaphragm (pressure detection unit) 12aA 1st page 12aB 2nd page 12b Strain resistance section 12c base 13 Main body 14 Sensor holding part 15 Sensor board 16. Zero point adjustment switch 17 Male screw 19 Cables 19a Cable mounting nut 20 flow path units 21 Flow channels 21A Flow channel body 22,22C Pressure-receiving diaphragm (pressure-receiving part) 22a 1st page 22b 2nd side 22d Annular groove 23,23C Connecting part (2nd connecting part) 23a Joining member 23a1 1st joint surface 23a2 2nd joint surface 23a2A recess 23a3 Communication hole 23b Magnetic material 23b1 C side 23b2 Convex part 30 Nut (Mounting Mechanism) 30a Female thread 30b Annular projection 100 Pressure detection device 200 Joining jigs 210 recess 300 glass plates 400 Retaining member AD Adhesive D1 1st outer diameter D2 2nd outer diameter D3 Third outer diameter P0 center position RD (Radial Direction) S Installation surface X axis Y1 axis Y2 axis

Claims

1. A pressure detection unit that detects the pressure transmitted to the pressure detection unit, A flow channel unit in which a fluid channel is formed, The system includes a mounting mechanism for detachably attaching the flow path unit to the pressure detection unit, The pressure detection unit, A pressure sensor having the pressure detection unit, It has a first connecting portion joined to the pressure detection portion, The aforementioned flow channel unit, A resin pressure-receiving part that is displaced by the pressure of the fluid flowing through the aforementioned channel, It has a second connecting portion joined to the pressure receiving portion, Either the first connecting portion or the second connecting portion has a magnet, and the other of the first connecting portion or the second connecting portion has a magnet or magnetic material. With the flow path unit attached to the pressure detection unit by the mounting mechanism, the first connecting portion and the second connecting portion are arranged in a state where they are attracted to each other by magnetic force. The pressure-receiving portion is formed in a circular shape when viewed from above, and is formed in a plate-like shape from the center to the edge. The second connecting portion is formed in a cylindrical shape extending along the axis and has a resin connecting member formed at both ends in the direction along the axis, with a first connecting surface that is joined to the pressure receiving portion and a second connecting surface that is joined to the magnet or the magnetic material. A pressure detection device in which the first joining surface and the pressure receiving portion of the joining member are joined by adhesive within a predetermined range surrounding the central position, and the second joining surface of the joining member and the magnet or magnetic material are joined by adhesive.

2. The pressure detection device according to claim 1, wherein the joining member has a communication hole that connects the first joining surface and the second joining surface and is located at the central position.

3. The pressure detection device according to claim 1, wherein the first outer diameter of the first joint surface viewed from above is set to be at least 1 / 3 and at least 1 / 2 times the second outer diameter of the region of the pressure-receiving part in contact with the fluid viewed from above.

4. The pressure detection device according to claim 1, wherein the outer diameter of the first connecting portion centered on the axis perpendicular to the pressure receiving portion is larger than the outer diameter of the second connecting portion centered on the axis.

5. The first joining surface is a flat surface located on a plane perpendicular to the axis, The second joining surface is a stepped surface with a recess formed at the central position, The magnet or magnetic material joined to the joining member has a protrusion formed at its central position. The pressure detection device according to any one of claims 1 to 4, wherein the joining member is joined to the magnet or the magnetic material with the protrusion inserted into the recess.

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