JP2012150073A - Pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensor which reduces weight and size, improve the efficiency of assembling work, and can be disassembled.SOLUTION: While an upper end surface of a lower frame 80 in a pipe member 20 abuts on a lower end surface of an upper frame 50 in an upper case 10, the lower frame 80 is fixed on the upper case 10 by a plurality of screws 17a. A flange upper end surface 82a of the lower frame 80 abuts on a projecting part lower end surface 24e of the pipe member 20. An upper end portion of the pipe member 20 is held by a lower end surface of a large-diameter portion 13 of the upper case 10 through an upper end portion of a design ring 90. Therefore, the pipe member 20 is sandwiched between the upper case 10 and the lower frame 80. A display substrate 40 is attached in the upper case 10. In the pipe member 20, a power supply substrate 60 and a main substrate 70 are held in an axial direction by the upper frame 50 and the lower frame 80.

Description

  The present invention relates to a pressure sensor for detecting pressure.

  Conventionally, various pressure sensors provided with a pressure element are used to detect water pressure in a water passage pipe (see, for example, Patent Document 1). Such a pressure sensor detects the water pressure in the pipe while being attached to a pipe joint, for example.

JP 2009-128076 A

  In recent years, a pressure sensor having a display unit for displaying a detected pressure such as water pressure has been developed. In such a pressure sensor, a circuit board on which electronic components are mounted is provided in a cylindrical main body case together with a pressure element for detecting pressure. In this pressure sensor, the main body case, the display unit, the circuit board, and the pressure element are fixed by filling the adhesive in almost the entire interior of the main body case. Thereby, vibration resistance is ensured.

  However, filling the main body case with the adhesive hinders weight reduction of the pressure sensor. Also, the pressure sensor cannot be disassembled. For this reason, failure analysis and repair of the pressure sensor cannot be performed when the pressure sensor fails.

  An object of the present invention is to provide a pressure sensor that can be reduced in weight, reduced in size, improved in assembly efficiency, and can be disassembled.

  (1) A pressure sensor according to the present invention includes an element holder having an internal space and having a pressure detection port and an upper opening, and a pressure that is accommodated in the internal space of the element holder and converts pressure received through the pressure detection port into an electrical signal. An element, a cylindrical member attached to the end of the element holder on the upper opening side, a first circuit board electrically connected to the pressure element, and a first circuit board housed in the cylindrical member, A lower frame held along the axial direction of the cylindrical member, a second circuit board having a display unit for displaying information based on an electric signal converted by the pressure element, and an upper opening of the cylindrical member so as to cover An upper case that is provided and accommodates the second circuit board; and a fixing member that fixes the lower frame to the upper case. The upper case has a slope portion that is inclined with respect to the axial direction of the cylindrical member, The circuit board 2 is mounted in the upper case along the slope portion, the slope portion has a first light-transmitting portion from which the display portion can be visually recognized from the outside, and the cylindrical member is first on the inner peripheral surface. The lower frame has a second convex portion on the outer peripheral surface, and the upper end surface of the second convex portion is the first convex portion with the lower frame fixed to the upper case by the fixing member. By pressing the lower end face, the cylindrical member is sandwiched between the lower frame and the upper case.

  In the pressure sensor, the element holder has an internal space and a pressure detection port and an upper opening. A pressure element is accommodated in the internal space of the element holder. The pressure received through the pressure detection port by the pressure element is converted into an electrical signal. A lower frame is accommodated in the cylindrical member, and the first circuit board is held by the lower frame along the axial direction of the cylindrical member. The first circuit board is electrically connected to the pressure element.

  The upper case has a slope portion inclined with respect to the axial direction of the cylindrical member. The second circuit board is accommodated in the upper case, and is mounted in the upper case along the slope portion. The second circuit board has a display unit that displays information based on the electrical signal converted by the pressure element. The slope part has the 1st translucent part which can visually recognize a display part from the outside. The upper case is provided so as to cover the upper opening of the cylindrical member. The lower frame is fixed to the upper case by a fixing member.

  The cylindrical member has a first protrusion on the inner peripheral surface, and the lower frame has a second protrusion on the outer peripheral surface. The cylindrical member is sandwiched between the lower frame and the upper case by the upper end surface of the second convex portion pressing the lower end surface of the first convex portion with the lower frame fixed to the upper case by the fixing member. . Thereby, the upper case, the cylindrical member, and the lower frame are fixed to each other. In this state, the cylindrical member is attached to the end portion on the upper opening side of the element holder.

  In this pressure sensor, the pressure received through the pressure detection port is converted into an electrical signal by the pressure element, and information based on the electrical signal is displayed on the display unit on the second circuit board. The information displayed by the display unit is visually recognized from the outside through the first light transmitting part of the slope part of the upper case. Since the display unit is provided in the upper case, the waterproofness of the display unit is ensured.

  As described above, the upper case, the cylindrical member, and the lower frame are fixed to each other by the fixing by the fixing member and the pressing of the first convex portion by the second convex portion, and the first by the lower frame in the cylindrical member. The circuit board is held, and the second circuit board is attached in the upper case. Thereby, it is possible to ensure the vibration resistance of the pressure sensor without filling the entire inside of the cylindrical member with the adhesive and without fixing the upper case, the cylindrical member and the lower frame from the outside. Further, when assembling the pressure sensor, a process of filling the adhesive into almost the entire inside of the cylindrical member becomes unnecessary. Thereby, the assembly time is shortened.

  Therefore, the pressure sensor is reduced in weight and size, and the efficiency of assembly work is improved. In addition, the upper case, the cylindrical member, the lower frame, the first circuit board, and the second circuit board can be easily disassembled.

  (2) The pressure sensor further includes an upper frame that holds the first circuit board along an axial direction of the cylindrical member at an upper portion of the lower frame in the cylindrical member, and the fixing member passes the lower frame through the upper frame. It may be fixed to the upper case.

  In this case, the first circuit board is held along the axial direction of the cylindrical member by the upper frame and the lower frame. Thereby, the vibration resistance of the first circuit board is sufficiently ensured.

  (3) The lower frame has a first guide groove in which the side end of the first circuit board is fitted, and the upper frame has a second guide groove in which the side end of the first circuit board is fitted. The first and second guide grooves may be formed on a common straight line along the axial direction of the cylindrical member.

  In this case, the side edge of the first circuit board is fitted into the first guide groove of the lower frame and the second guide groove of the upper frame formed on a common straight line along the axial direction of the cylindrical member. The Thereby, the first circuit board is easily held along the axial direction of the cylindrical member. Therefore, the efficiency of the assembly work is sufficiently improved and the vibration resistance of the first circuit board is sufficiently ensured.

  (4) The element holder has a flange portion formed so as to surround the upper opening, and even if the cylindrical member is fixed to the element holder by caulking the lower end portion of the cylindrical member to the flange portion of the element holder. Good.

  In this case, the element holder is fixed to the lower end portion of the cylindrical member by a caulking structure. Thereby, the cylindrical member can be rotated with respect to the element holder. Therefore, the user can easily change the orientation of the display unit.

  (5) The second circuit board further includes an indicator lamp that displays the operating state of the pressure end element, and the upper case has a second light transmission that allows the indicator lamp to be visually recognized from the outside on the top of the slope portion. You may have a part.

  In this case, it is visually recognized from the outside through the second light transmitting portion at the top of the slope portion of the upper case. Thereby, the waterproofness of the indicator lamp is ensured. Moreover, the user can visually recognize the indicator lamp from all directions.

  According to the present invention, the pressure sensor can be reduced in weight and size, the efficiency of assembly work can be improved, and the pressure sensor can be disassembled.

It is an external appearance perspective view of the pressure sensor which concerns on this Embodiment. It is the disassembled perspective view which looked at each component of the pressure sensor from diagonally upward. It is the disassembled perspective view which looked at each component of the pressure sensor from diagonally downward. It is the external appearance perspective view which looked at the upper case from diagonally upward. It is the external appearance perspective view which looked at the upper case from diagonally downward. It is the bottom view which looked at the upper case from the lower part. It is the external appearance perspective view which looked at the lower frame from diagonally upward. It is the external appearance perspective view which looked at the lower frame from diagonally downward. It is a notch perspective view of a pipe member, a lower frame, and an element holder. It is sectional drawing of the whole pressure sensor. It is a partial expanded sectional view of a pipe member, a lower frame, a washer group, and an element holder.

  Hereinafter, a pressure sensor according to an embodiment of the present invention will be described with reference to the drawings.

(1) Structure of Pressure Sensor FIG. 1 is an external perspective view of a pressure sensor according to the present embodiment. As shown in FIG. 1, the pressure sensor 1 includes an upper case 10, a pipe member 20, and an element holder 30. The upper case 10, the pipe member 20, and the element holder 30 each have a substantially cylindrical shape and have a common axis. Hereinafter, the direction parallel to the common axis of the upper case 10, the pipe member 20, and the element holder 30 is defined as the axial direction. The upper case 10 is attached to the upper end portion of the pipe member 20 via the design ring 90, and the element holder 30 is attached to the lower end portion of the pipe member 20. A male screw is formed on the outer peripheral surface of the element holder 30.

  The upper case 10 has a slope portion 15 that is inclined with respect to the axial direction. The slope portion 15 is provided with a transparent display window 11 and a transparent indicator lamp cover 12. In the upper case 10, a display unit 41 is disposed so as to be visible through the display window 11, and an operation indicator lamp 42 is disposed so as to be visible through the display lamp cover 12. The display unit 41 displays various information such as a pressure value detected by a pressure element 120 (FIG. 2) described later in numerical values. The operation indicator lamp 42 displays the operation state of the pressure sensor 1. For example, the operation indicator lamp 42 lights up when the pressure value detected by the pressure element 120 exceeds a preset threshold value. The operation indicator lamp 42 may be lit in a different color depending on the operation state.

  Below the display window 11, an upper key 43a, a lower key 43b, and an enter key 43c are provided. The user can set, for example, the above threshold value by operating the up key 43a, the down key 43b, and the enter key 43c.

  A cylindrical terminal port 25 is provided so as to protrude outward from the outer peripheral surface of the pipe member 20. A plurality of terminals 26 are provided in the terminal port 25. The plurality of terminals 26 are, for example, a pair of power supply terminals and a pair of output terminals. A connector for connection with an external device (not shown) is inserted into the terminal port 25.

  2 is an exploded perspective view of each component of the pressure sensor 1 shown in FIG. 1 as viewed obliquely from above. FIG. 3 is an exploded perspective view of the components of the pressure sensor 1 shown in FIG. is there.

  As shown in FIGS. 2 and 3, in the upper case 10, the pipe member 20, and the element holder 30, there are a display substrate 40, an upper frame 50, a power supply substrate 60, a main substrate 70, a lower frame 80, a pressure element 120, a preamplifier. The substrate 130 and the protective ring 140 are accommodated. The upper case 10, the upper frame 50, and the lower frame 80 are made of plastic, for example. The pipe member 20, the element holder 30, and the protection ring 140 are formed of a metal such as stainless steel, for example. The display board 40, the power supply board 60, the main board 70, and the preamplifier board 130 are circuit boards.

  The display substrate 40 has a substantially elliptical shape. A display unit 41 and an operation indicator lamp 42 are provided on the display substrate 40. The display unit 41 includes a liquid crystal display panel, a 7 segment LED (light emitting diode) panel, or the like. The operation indicator lamp 42 includes a light emitting element such as an LED. A translucent protective cover 44 is attached on the display substrate 40 so as to cover the operation indicator lamp 42. A display drive circuit for driving the display unit 41 and the operation indicator lamp 42 is mounted on the display substrate 40. On the display substrate 40, switches 45a, 45b, and 45c connected to the display driving circuit are mounted. The upper key 43a, the lower key 43b, and the enter key 43c are made of hard plastic and attached to a common pressing member 43d made of rubber. The pressing member 43d is attached on the display substrate 40 so as to cover the switches 45a, 45b, and 45c.

  By pressing the upper key 43a, the lower key 43b, and the enter key 43c, the switches 45a, 45b, and 45c are turned on and off, respectively. The on / off of the switches 45a, 45b, 45c is input to the display driving circuit on the display substrate 40. The user can change the display content of the display unit 41, set the threshold value, change the display content of the operation indicator lamp 42, and the like by operating the upper key 43a, the lower key 43b, and the enter key 43c.

  The upper frame 50 has a substantially cylindrical shape. A pair of guide grooves 55 a (FIG. 3) and a pair of guide grooves 55 b (FIG. 3) extending in the axial direction are formed on the inner peripheral surface of the upper frame 50. One guide groove 55a and one guide groove 55b are provided adjacent to each other, and the other one guide groove 55a and the other one guide groove 55b are provided adjacent to each other. The pair of guide grooves 55a face each other, and the pair of guide grooves 55b face each other. An annular flange portion 56 is formed at the lower end portion of the upper frame 50 so as to protrude outward by a predetermined width. A plurality (four in this example) of notches 54 are formed in the flange portion 56 at intervals in the circumferential direction.

  The display substrate 40, the upper key 43 a, the lower key 43 b, the enter key 43 c, the protective cover 44 and the upper frame 50 are accommodated in the upper case 10. Details of the upper case 10 will be described later.

  The lower end portion of the upper case 10 is fitted into the upper opening of the pipe member 20 via the design ring 90 and the packing 100. The design ring 90 is formed of, for example, a plastic having a color different from that of the upper case 10. The packing 100 is made of rubber, for example.

  Further, the lower frame 80 is inserted into the pipe member 20 from the lower opening of the pipe member 20. The power supply board 60 and the main board 70 are held by the lower frame 80. Details of the lower frame 80 will be described later. The power supply board 60 and the main board 70 have a substantially rectangular shape. A power supply circuit is mounted on the power supply board 60. A control circuit is mounted on the main board 70. A pair of power supply terminals of the plurality of terminals 26 in FIG. 2 are connected to the power supply board 60, and a pair of output terminals of the plurality of terminals 26 are connected to the main board 70. The power supply substrate 60 is electrically connected to the display substrate 40, the main substrate 70, and a preamplifier substrate 130 described later. Main substrate 70 is electrically connected to display substrate 40 and preamplifier substrate 130.

  As shown in FIG. 2, the element holder 30 includes a cylindrical portion 31 and a flange portion 32, and has an internal space 33 and an upper opening. The flange portion 32 is formed integrally with the upper end of the cylindrical portion 31. The outer diameter of the flange portion 32 is larger than the outer diameter of the cylindrical portion 31. An annular groove portion is formed on the outer peripheral surface of the flange portion 32, and a packing 36 is attached to the groove portion. A rotation stop pin 34 is provided so as to protrude upward from the upper end surface of the flange portion 32.

  An annular packing 110, a pressure element 120, a preamplifier substrate 130, and a protection ring 140 are accommodated in the internal space 33 of the element holder 30. The preamplifier substrate 130 has a circular shape. An amplifier circuit is mounted on the preamplifier substrate 130. A pressure detection port 35 (FIG. 3) is provided at the bottom of the cylindrical portion 31. Further, a vent hole 37 is formed on the side of the cylindrical portion 31, and a waterproof lid 38 is fitted into the vent hole 37. A material that transmits gas and does not transmit liquid is attached to the waterproof lid 38. The flange portion 32 of the element holder 30 is fitted into the lower opening of the pipe member 20 via the washer group 150.

  4 is an external perspective view of the upper case 10 as viewed obliquely from above, FIG. 5 is an external perspective view of the upper case 10 as viewed obliquely from below, and FIG. 6 is a bottom view of the upper case 10 as viewed from below. is there. As shown in FIGS. 4 to 6, the upper case 10 includes a large diameter portion 13 and a small diameter portion 14. The outer diameter of the large diameter portion 13 is larger than the outer diameter of the small diameter portion 14. Thereby, a step surface is formed between the outer peripheral surface of the large diameter portion 13 and the outer peripheral surface of the small diameter portion 14. The large diameter portion 13 has a slope portion 15.

  A rectangular display window 11 is provided at a substantially central portion of the slope portion 15, and an indicator lamp cover 12 is provided at the top of the slope portion 15. The display unit 41 on the display substrate 40 of FIG. 2 is arranged in the upper case 10 so as to overlap the display window 11, and the operation indicator lamp 42 and the protective cover 44 on the display substrate 40 in the upper case 10 are the indicator lamp cover 12. It is arranged to overlap.

  The display window 11 and the indicator lamp cover 12 are made of transparent plastic, and the other parts of the upper case 10 excluding the indicator window 11 and the indicator lamp cover 12 are made of, for example, black plastic. The part of the display window 11 and the indicator lamp cover 12 and the other part of the upper case 10 are integrally formed. With such a structure, waterproofness of the display unit 41 and the operation indicator lamp 42 in the upper case 10 is ensured.

  Key insertion holes 16 a, 16 b, and 16 c are provided in the area of the slope 15 at the lower portion of the display window 11. Further, as shown in FIGS. 5 and 6, screw holes 18 are formed between the key insertion hole 16a and the key insertion hole 16b on the back side of the slope portion 15 and on both sides of the key insertion hole 16c. 2 are inserted into the key insertion holes 16a, 16b, and 16c so that the upper key 43a, the lower key 43b, and the enter key 43c in FIG. 2 protrude onto the slope portion 15, and the pressing member 43d in FIG. Close contact with. In this state, the screw is screwed into the screw hole 18 of the slope portion 15 through the screw hole of the display substrate 40 of FIG. Thereby, the display substrate 40 is fixed to the back side of the slope portion 15. With such a structure, waterproofness of the display substrate 40 in the upper case 10 is ensured.

  As shown in FIG. 5 and FIG. 6, a plurality (four in this example) of screw holes 17 are formed on the lower end surface of the small diameter portion 14 at intervals in the circumferential direction. Each screw hole 17 has a certain depth in the axial direction.

  FIG. 7 is an external perspective view of the lower frame 80 as viewed obliquely from above, and FIG. 8 is an external perspective view of the lower frame 80 as viewed from obliquely below. As shown in FIGS. 7 and 8, the lower frame 80 includes a cylindrical portion 81 and an annular flange portion 82. The flange portion 82 is formed at the lower end of the cylindrical portion 81. The outer diameter of the flange portion 82 is larger than the outer diameter of the cylindrical portion 81. An annular flange upper end surface 82a perpendicular to the axial direction is formed between the outer peripheral surface of the cylindrical portion 81 and the outer peripheral surface of the flange portion 82.

  A plurality (four in this example) of through holes 84 are formed in the upper end portion of the cylindrical portion 81 at intervals in the circumferential direction. The plurality of through holes 84 are arranged on the inner side of the inner peripheral surface of the cylindrical portion 81. The screw 17a of FIG. 2 is inserted into each through hole 84 from the lower opening of the cylindrical portion 81. A substantially rectangular opening 83 is formed below each of the plurality of through holes 84 of the cylindrical portion 81. A part of the screw thread of the screw 17 a inserted into the through hole 84 is located in the opening 83. A pair of guide grooves 85 a and a pair of guide grooves 85 b extending in the axial direction are formed on the inner peripheral surface of the cylindrical portion 81. One guide groove 85a and one guide groove 85b are provided adjacent to each other between the two openings 83, and the other one guide groove 85a and the other one guide groove 85b are the other two openings 83. Are provided adjacent to each other. The pair of guide grooves 85a face each other, and the pair of guide grooves 85b face each other. A U-shaped notch 86 that opens upward is formed in the region of the side surface of the cylindrical portion 81 between the pair of guide grooves 85a.

  The pair of guide grooves 55a of the upper frame 50 and the pair of guide grooves 85a of the lower frame 80 shown in FIG. 3 are respectively arranged on a common straight line along the axial direction. The pair of guide grooves 85b of the frame 80 are arranged on a common straight line along the axial direction.

  Both ends of the power supply substrate 60 are fitted into the pair of guide grooves 55 a of the upper frame 50 and the pair of guide grooves 85 a of the lower frame 80. Further, both side ends of the main board 70 are fitted into the pair of guide grooves 55 b of the upper frame 50 and the pair of guide grooves 85 b of the lower frame 80. The power supply substrate 60 is fixed to the pair of guide grooves 85a of the lower frame 80 with an adhesive, and the main substrate 70 is fixed to the pair of guide grooves 85b of the lower frame 80 with an adhesive. In this case, the adhesive is applied only to both side edges of the power supply board 60 and both side edges of the main board 70, and the other parts of the power supply board 60 and the other parts of the main board 70 are not covered with the adhesive.

  The plurality of screw holes 17 in the upper case 10, the plurality of notches 54 in the upper frame 50, and the plurality of through holes 84 in the lower frame 80 are arranged on a common straight line along the axial direction.

  With the display substrate 40 attached to the upper case 10, the upper frame 50 is fitted into the upper case 10. Further, the small diameter portion 14 of the upper case 10 is fitted into the pipe member 20 from the upper opening of the pipe member 20 in a state where the design ring 90 and the packing 100 are fitted to the small diameter portion 14 of the upper case 10. Further, the lower frame 80 is fitted into the pipe member 20 from the lower opening of the pipe member 20 with the power supply substrate 60 and the main substrate 70 attached to the lower frame 80. In this state, the screws 17 a are screwed into the screw holes 17 of the upper case 10 through the through holes 84 of the lower frame 80 and the notches 54 of the upper frame 50 from the lower opening of the pipe member 20. Thereby, the upper case 10, the upper frame 50, and the lower frame 80 are fixed to each other. Further, the upper case 10, the upper frame 50 and the lower frame 80 are fixed to the pipe member 20 by the pipe member 20 being sandwiched between the upper case 10 and the lower frame 80. The detailed structure of this state will be described later.

  9 is a cutaway perspective view of the pipe member 20, the lower frame 80, and the element holder 30, FIG. 10 is a cross-sectional view of the entire pressure sensor 1, and FIG. 11 shows the pipe member 20, the lower frame 80, 4 is a partially enlarged cross-sectional view of the washer group 15 and the element holder 30. FIG. In FIG. 10, the lower frame 80 is indicated by a two-dot chain line.

  As shown in FIG. 9, the pipe member 20 has a thick part 21, a middle part 23, and thin parts 22 and 24. The thin portion 22 extends upward from the upper end portion of the thick portion 21, and the middle portion 23 and the thin portion 24 extend downward from the lower end portion of the thick portion 21. The inner diameter of the thick part 21 is smaller than the inner diameters of the thin parts 22, 24 and the middle part 23. Therefore, an annular convex portion 21 a extending in the circumferential direction is formed on the inner peripheral surface of the pipe member 20. The convex part 21a has an annular convex lower end surface 24e perpendicular to the axial direction (FIG. 11).

  As shown in FIG. 10, the outer diameter of the upper frame 50 is substantially equal to the inner diameter of the upper case 10. The inner diameter of the design ring 90 is substantially equal to the outer diameter of the small diameter portion 14 of the upper case 10. The outer diameter of the design ring 90 is substantially equal to the inner diameter of the thin portion 22 of the pipe member 20. The outer diameter of the lower frame 80 is slightly smaller than the inner diameter of the thick part 21 of the pipe member 20. The inner diameter of the thin portion 24 of the pipe member 20 is substantially equal to the outer diameter of the flange portion 32 of the element holder 30.

  The terminal port 25 is provided so as to protrude to the inside of the pipe member 20 by a certain length. In the pipe member 20, the lower frame 80 indicated by a two-dot chain line is disposed such that the outer peripheral surface of the cylindrical portion 81 is along the inner peripheral surface of the thick portion 21. The portion of the terminal port 25 protruding inward of the pipe member 20 is fitted into the U-shaped notch 86 (FIGS. 7 and 8) of the lower frame 80.

  As shown in FIG. 10, the display substrate 40 is attached along the inclined surface 15 of the upper case 10 in the upper case 10. An upper frame 50 is disposed inside the upper case 10 below the display substrate 40. The upper end surface of the flange portion 54 at the lower end of the upper frame 50 contacts the lower end surface of the small diameter portion 14 of the upper case 10.

  The upper end surface of the lower frame 80 is in contact with the lower end surface of the upper frame 50. In this state, as described above, the upper case 10, the upper frame 50, and the lower frame 80 are fixed to each other by the plurality of screws 17a (FIG. 3).

  In this case, as shown in FIG. 11, the flange upper end surface 82 a of the lower frame 80 abuts on the convex lower end surface 24 e of the pipe member 20. Thereby, the flange upper end surface 82 a of the lower frame 80 presses the convex lower end surface 24 e of the pipe member 20. As shown in FIG. 10, the upper end portion of the pipe member 20 is held by the lower end surface (step surface) of the large-diameter portion 13 of the upper case 10 via the upper end portion of the design ring 90. Accordingly, the pipe member 20 is sandwiched between the upper case 10 and the lower frame 80.

  With such a structure, the upper case 10, the upper frame 50, the lower frame 80, and the pipe member 20 are fixed to each other.

  A packing 100 is disposed between the outer peripheral surface of the small diameter portion 14 of the upper case 10 and the inner peripheral surface of the thin portion 22 of the pipe member 20. The packing 100 is in close contact with the outer peripheral surface of the small diameter portion 14 and the inner peripheral surface of the thin portion 22. Thereby, the liquid tightness between the upper case 10 and the pipe member 20 is ensured.

  As shown in FIGS. 9 and 10, an annular groove is formed at the bottom of the cylindrical portion 31 of the element holder 30 so as to surround the pressure detection port 35, and the packing 110 is fitted into the groove. The pressure element 120 is disposed in the cylindrical portion 31 so as to close the pressure detection port 35. The packing 110 is in close contact with the bottom surface of the pressure element 120. Thereby, the liquid-tightness between the bottom part of the element holder 30 and the pressure element 120 is ensured. A preamplifier substrate 130 is disposed on the pressure element 120. The preamplifier substrate 130 has a circular shape. The terminal of the pressure element 120 extends upward and is connected to the preamplifier substrate 130. A protection ring 140 is disposed on the pressure element 120 so as to surround the preamplifier substrate 130.

  The flange portion 32 of the element holder 30 is disposed in the thin portion 24 of the pipe member 20. An annular groove portion is formed on the outer peripheral surface of the flange portion 32, and a packing 36 is fitted into the groove portion. The packing 36 is in close contact with the inner peripheral surface of the thin portion 24 of the pipe member 20. Thereby, the liquid tightness between the thin portion 24 of the pipe member 20 and the flange portion 32 of the element holder 30 is ensured.

  A washer group 150 is disposed between the flange portion 81 of the lower frame 80 and the flange portion 32 of the element holder 30. As shown in FIG. 11, the washer group 150 includes a SUS (stainless steel) washer 151, a wave washer 152, a SUS washer 153, and a brass washer 154 in order from the lower frame 80 side to the element holder 30 side. The upper surface of the SUS washer 151 comes into contact with the lower end surface of the inner wall portion 23 of the pipe member 20. The lower surface of the brass washer 154 contacts the upper end surface of the flange portion 32 of the element holder 30.

  A resin sheet 160 having an L-shaped cross section made of, for example, polypropylene is attached so as to cover the lower end edge of the flange portion 32 of the element holder 30. As shown in FIGS. 10 and 11, the lower end portion of the thin portion 24 of the pipe member 20 is caulked inward. Thereby, the pipe member 20 is rotatably fixed to the element holder 30. FIG. 9 shows a state before caulking of the lower end portion of the thin portion 24 of the pipe member 20. The torque required when the user rotates the pipe member 20 relative to the element holder 30 is adjusted by the washer group 150. Further, the resin sheet 160 is interposed in the sliding portion between the pipe member 20 and the element holder 30, whereby the pipe member 20 can be smoothly rotated with respect to the element holder 30.

  As shown in FIGS. 9 and 10, the rotation stop pin 34 provided on the upper end surface of the element holder 30 protrudes upward inside the washer group 150. The rotation stop pin 34 is disposed so as to be able to contact a part of the lower frame 80. Thereby, the rotation range of the pipe member 20 with respect to the element holder 30 is limited to a certain angle.

(2) Operation of Pressure Sensor When the pressure sensor 1 according to the present embodiment is used, the element holder 30 is attached to, for example, a pipe joint provided in the pipe. Power is supplied from the outside to the power supply board 60 of the pressure sensor 1 through the terminal 26 of the terminal port 25. The power supply circuit of the power supply substrate 60 supplies a predetermined voltage to the display substrate 40, the main substrate 70, and the preamplifier substrate 130. The pressure element 120 converts the pressure received through the pressure detection port 35 into an electrical signal and outputs the electrical signal. The amplification circuit of the preamplifier substrate 130 amplifies the electrical signal output from the pressure element 120 and provides the amplified electrical signal to the main substrate 70 as a detection signal. The control circuit of the main board 70 performs various processes on the detection signal given from the preamplifier board 130. For example, the control circuit gives information indicating a pressure value or the like to the display substrate 40 based on the detection signal and outputs the information from the terminal 26 to the outside. In addition, the control circuit compares the detection signal with a preset threshold value and gives the comparison result to the display substrate 40. The display unit 42 of the display substrate 40 displays information such as a pressure value given from the control circuit as a numerical value. Further, the operation indicator lamp 42 of the display substrate 40 is turned on and off according to the operation state. For example, the light is turned on when the detection signal is larger than the threshold value based on the comparison result given from the control circuit.

  The user can view the information displayed on the display unit 41 through the display window 11 of the slope portion 15 of the upper case 10. Further, the user can visually recognize the state of the operation indicator lamp 42 from all directions through the indicator lamp cover 12 at the top of the slope portion 15.

(3) Effects of the Embodiment In the pressure sensor 1 according to the present embodiment, the upper end surface of the lower frame 80 in the pipe member 20 is in contact with the lower end surface of the upper frame 50 in the upper case 10. The lower frame 80 is fixed to the upper case 10 by a plurality of screws 17a. In this case, as shown in FIG. 11, the flange upper end surface 82 a of the lower frame 80 abuts against the convex lower end surface 24 e of the pipe member 20. Thereby, the flange upper end surface 82 a of the lower frame 80 presses the convex lower end surface 24 e of the pipe member 20. As shown in FIG. 10, the upper end portion of the pipe member 20 is held by the lower end surface (step surface) of the large-diameter portion 13 of the upper case 10 via the upper end portion of the design ring 90. Accordingly, the pipe member 20 is sandwiched between the upper case 10 and the lower frame 80. With such a structure, the upper case 10, the upper frame 50, the lower frame 80, and the pipe member 20 are fixed to each other.

  The display substrate 40 is attached in the upper case 10. Further, the power board 60 and the main board 70 are held in the pipe member 20 along the axial direction by the upper frame 50 and the lower frame 80.

  Thereby, the vibration resistance of the pressure sensor 1 is ensured without filling the entire internal space of the pipe member 20 and without fixing the upper case 10, the pipe member 20, and the lower frame 80 from the outside. be able to. Therefore, the pressure sensor 1 is reduced in weight and size. Further, when the pressure sensor 1 is assembled, a process of filling the entire internal space of the pipe member 20 with an adhesive becomes unnecessary. Thereby, the assembly time is shortened. Furthermore, the upper case 10, the upper frame 50, the pipe member 20, the lower frame 80, the display substrate 40, the power supply substrate 60, and the main substrate 70 can be easily disassembled.

  Further, both ends of the power supply substrate 60 are fitted into the pair of guide grooves 55 a of the upper frame 50 and the pair of guide grooves 85 a of the lower frame 80, and the pair of guide grooves 55 b of the upper frame 50 and the pair of guides of the lower frame 80. Both ends of the main board 70 are fitted into the groove 85b. Thereby, the power supply board 60 and the main board 70 are easily and reliably held in the pipe member 20 along the axial direction. As a result, the efficiency of the assembly operation of the pressure sensor 1 is sufficiently improved, and the vibration resistance of the power supply board 60 and the main board 70 is sufficiently ensured.

  Further, the element holder 30 is fixed to the lower end portion of the pipe member 20 by a caulking structure. Thereby, the pipe member 20 can be rotated by a certain angle with respect to the element holder 30. Therefore, the user can easily change the orientation of the display window 11 of the upper case 10.

  Further, the display unit 41 and the operation indicator lamp 42 are accommodated in the integrally formed upper case 10. Thereby, the waterproofness of the display part 41 and the operation indicator lamp 42 is ensured.

(4) Other Embodiments In the above embodiment, the power supply board 60 and the main board 70 are provided separately, but the present invention is not limited to this. The power supply board 60 and the main board 70 may be provided as a common circuit board.

  In the above embodiment, the upper case 50 is provided together with the lower case 80, but the upper case 50 may not be provided. Alternatively, the lower case 80 and the upper case 50 may be integrally formed.

  In the above embodiment, the flange upper end surface 82a abuts the convex lower end surface 24e of the pipe member 20, and the flange upper end surface 82a presses the convex lower end surface 24e. Another member may be interposed between the end surface 24e. In this case, the flange upper end surface 82a presses the convex portion lower end surface 24e via another member.

  In the above embodiment, the convex portion 21a is formed in an annular shape on the inner peripheral surface of the pipe member 20, but the present invention is not limited to this, and the convex portion 21a is formed on a part of the inner peripheral surface of the pipe member 20 in the circumferential direction. It may be provided. Moreover, in the said embodiment, although the annular | circular shaped flange part 82 contact | abutted to the convex part 21a of the pipe member 20 is provided in the lower frame 80, it is not limited to this, The convex contact | abutted to the convex part 21a of the pipe member 20 The portion may be formed in a part of the outer peripheral surface of the lower frame 80 in the circumferential direction instead of the flange portion 82.

(5) Correspondence between each constituent element of claim and each element of the embodiment Hereinafter, an example of correspondence between each constituent element of the claim and each element of the embodiment will be described. It is not limited to.

  In the above embodiment, the element holder 30 is an example of an element holder, the pressure element 120 is an example of a pressure element, the pipe member 20 is an example of a cylindrical member, and the power supply board 60 and the main board 70 are the first. The lower frame 80 is an example of a lower frame, the display unit 41 is an example of a display unit, the display substrate 40 is an example of a second circuit board, and the upper case 10 is an upper case. The screw 17a is an example of a fixing member.

  Further, the slope portion 15 is an example of the slope portion, the display window 11 is an example of the first light transmitting portion, the convex portion 21a is an example of the first convex portion, and the flange portion 82 is the second convex portion. It is an example of a part.

  Furthermore, the upper frame 50 is an example of the upper frame, the guide grooves 85a and 85b are examples of the first guide groove, the guide grooves 55a and 55b are examples of the second guide groove, and the flange of the element holder 30 The portion 32 is an example of the flange portion of the element holder, the lower end portion of the thin portion 24 of the pipe member 20 is an example of the lower end portion of the cylindrical member, the operation indicator lamp 42 is an example of the indicator lamp, and the indicator lamp cover 12 is an example of a 2nd translucent part.

  As each constituent element in the claims, various other elements having configurations or functions described in the claims can be used.

  The present invention can be used to detect pressure.

DESCRIPTION OF SYMBOLS 1 Pressure sensor 10 Upper case 11 Display window 12 Indicator lamp cover 13 Large diameter part 14 Small diameter part 15 Slope part 16a, 16b, 16c Key insertion hole 17 Screw hole 17a Screw 20 Pipe member 21 Thick part 22, 24 Thin part 23 In Meat part 21a Convex part 24e Convex part lower end surface 25 Terminal port 26 Terminal 30 Element holder 31 Cylindrical part 32, 56, 82 Flange part 33 Internal space 34 Anti-rotation pin 35 Pressure detection port 36, 100, 110 Packing 37 Ventilation hole 38 Waterproof cover 40 Display board 41 Display section 42 Operation indicator 43a Up key 43b Down key
43c Enter key 43d Press member 44 Protective cover 50 Upper frame 54 Notch 55a, 55b Guide groove 60 Power supply board 70 Main board 81 Cylindrical part 81e, 82a Flange upper end surface 83 Opening 84 Through hole 80 Lower frame 85a, 85b Guide groove 86 U Notch 90 Design ring 120 Pressure element 130 Preamplifier board 140 Protective ring 150 Washer group 151,153 SUS washer 152 Wave washer 154 Brass washer 160 Resin sheet

Claims (5)

An element holder having an internal space and having a pressure detection port and an upper opening;
A pressure element that is housed in the internal space of the element holder and converts pressure received through the pressure detection port into an electrical signal;
A cylindrical member attached to an end of the element holder on the upper opening side;
A first circuit board electrically connected to the pressure element;
A lower frame housed in the cylindrical member and holding the first circuit board along an axial direction of the cylindrical member;
A second circuit board having a display unit for displaying information based on the electrical signal converted by the pressure element;
An upper case provided to cover the upper opening of the cylindrical member and accommodating the second circuit board;
A fixing member for fixing the lower frame to the upper case,
The upper case has a slope portion that is inclined with respect to the axial direction of the cylindrical member, and the second circuit board is mounted in the upper case along the slope portion, and the slope portion is external. A first light-transmitting part capable of visually recognizing the display part,
The cylindrical member has a first protrusion on the inner peripheral surface, the lower frame has a second protrusion on the outer peripheral surface, and the lower frame is fixed to the upper case by the fixing member The pressure sensor is characterized in that the cylindrical member is sandwiched between the lower frame and the upper case when the upper end surface of the second convex portion presses the lower end surface of the first convex portion. An upper frame for holding the first circuit board along the axial direction of the cylindrical member at the upper part of the lower frame in the cylindrical member;
The pressure sensor according to claim 1, wherein the fixing member fixes the lower frame to the upper case through the upper frame. The lower frame has a first guide groove into which a side end of the first circuit board is fitted, and the upper frame has a second guide groove into which a side end of the first circuit board is fitted. 3. The pressure sensor according to claim 2, wherein the first and second guide grooves are formed on a common straight line along an axial direction of the cylindrical member. The element holder has a flange portion formed so as to surround the upper opening,
The pressure sensor according to claim 1, wherein the cylindrical member is fixed to the element holder by caulking a lower end portion of the cylindrical member to the flange portion of the element holder. . The second circuit board further includes an indicator lamp that displays an operation state of the pressure sensor,
The pressure sensor according to any one of claims 1 to 4, wherein the upper case has a second light-transmitting portion that allows the indicator lamp to be visually recognized from the outside at the top of the slope portion.

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