JP5542638B2 - Pressure detector - Google Patents

Description

  The present invention relates to a pressure detector such as a pressure sensor and a pressure switch, and more particularly, a pressure sensor in which a liquid is enclosed in an indirect pressure receiving chamber containing a pressure detecting element, or a contact through a pressure receiving diaphragm without enclosing the liquid. The present invention relates to a pressure detector such as a pressure switch that opens and closes a pressure detector, and fixes a pressure introduction pipe to a detector body such as a lid member (receiving member).

  Conventionally, liquid (oil) is sealed in a pressure detection chamber (pressure receiving space) in which a semiconductor pressure sensor element is housed, and pressure applied from the outside to the pressure detection chamber is applied to the semiconductor pressure sensor element via the liquid. Various semiconductor pressure detectors that output a voltage signal corresponding to pressure from the pressure sensor element have been proposed.

  In pressure detectors such as pressure sensors and pressure switches, fluid pressure received through a diaphragm is transmitted to sensor elements and contacts. Therefore, it is necessary to attach a conduit for introducing a fluid into the pressure detection chamber in which the diaphragm is disposed. As an example of the pressure sensor, Patent Literature 1 discloses a liquid that is sealed in an indirect pressure receiving chamber in which a pressure detection element is accommodated, and that includes a housing and a connector case.

  FIG. 6 is a diagram illustrating an example of a pressure sensor, and includes a lid member 2, a diaphragm 3, a holder (base) 1 that sandwiches a peripheral portion of the diaphragm 3 between the lid member (receiving member) 2, and a holder And a diaphragm 3 and a pressure detection element 41 disposed in a pressure receiving space 31 into which pressure is introduced, and a connector case (cover) 60 that covers the outside of the holder. The lid member 2, the diaphragm 3, the holder 1, and a collar for fixing the connector case 60 integrally from the outside can also be provided.

  The lid member 2 of the pressure sensor 100 is made of, for example, stainless steel, and is formed in a disc shape as a whole. 2a. An opening 2 b is formed at the center of the lid member 2, and a pressurizing space (pressure introducing space) 12 is formed inside the lid member 2 by a diaphragm 3 and on the side opposite to the pressure receiving space 31. Yes. A fluid inflow pipe (conduit or pressure introducing pipe) 11 communicating with the pressurizing space 12 is brazed to the opening 2 b of the lid member 2 by a welding portion. A rib 99 is bent at the end of the fluid inflow pipe 11, and the rib 99 is pressed against the receiving member 2 to position the fluid inflow pipe 11 with respect to the receiving member 2 during brazing. . When the fluid inflow pipe 11 is fixed to the receiving member 2, the step is formed by cutting the outer periphery of the end of the fluid inflow pipe 11 instead of the rib 99, and the cut end is used as a lid member. It is also inserted into the hole formed in the above and fixed (welded) after abutting at the stepped portion (Patent Document 1). Thus, the rib 99 or the cut end portion has a positioning function.

  Patent Document 2 discloses a detector main body case in which a terminal block and a main body case are coupled to each other by a caulking ring member as an example of a pressure switch. The terminal block defines an electrical contact chamber 23 in which a fixed contact and a movable contact that can be moved toward and away from the fixed contact are provided. The diaphragm has a pressure receiving chamber defined between itself and the main body case. The diaphragm is made of a metal having a spring property that reverses in response to the pressure of the pressure receiving chamber, that is, a snap action. When the pressure is less than the set value, the fixed contact and the movable contact are brought into conductive contact with the lower side, and when the pressure in the pressure receiving chamber exceeds the set value, the shape swells upward. And the movable contact is moved away from the fixed contact. Further, between the terminal block and the main body case, an intermediate guide member, a stopper member, and a diaphragm are fixed in an airtight manner with an O-ring interposed therebetween.

  A joint pipe such as a copper pipe that communicates with the pressure receiving chamber and introduces pressure has a rib formed at its end, and the end is inserted into a hole formed in the main body case and the rib is pushed into the main body case. It is fixed (welded) after being applied. Thus, the rib has a function of positioning the joint pipe. In order to protect the diaphragm from the pulsation pressure and impact pressure of the fluid whose pressure is to be detected, a throttle member is disposed and fixed in the joint pipe.

JP 2003-287472 A JP 2004-012140 A

  As can be seen from the examples shown in Patent Document 1 and Patent Document 2, a conduit for introducing pressure into the body of a pressure detector such as a pressure sensor or a pressure switch is fixed to the body. A step or rib is formed at the end of the base plate, and the step or rib is pressed against the edge of the lid member or the opening of the main body case and positioned (welding) in the step or rib. Has been done. Due to the structure of the stepped portion and the rib, the size and the specification have a great influence, and it is difficult to ensure a sufficient width for contacting the main body. Therefore, in the contact structure of the stepped portion or the rib, the width of the contact becomes narrow, and the positioning state of the conduit to the main body is unstable. Furthermore, in fixing with a stepped portion or a rib, the portion that is in contact is fixed by welding, so it is necessary to pay attention to both maintaining the contact state and fixing work, and the work is complicated.・ It is difficult.

  Further, in the case shown in Patent Document 2, since the throttle device is formed long in the axial direction of the conduit, the pressure detector is enlarged and a rib is required to fix the conduit. The structure of the pipe mounting portion is complicated. Further, even if the aperture device shown in Patent Document 2 is applied to a pressure sensor as shown in Patent Document 1, there is a similar problem.

Therefore, as a structure for fixing a conduit for introducing pressure into the main body of the pressure detector such as a pressure sensor or a pressure switch, the position for positioning the conduit to the main body at the time of the fixing, and fixing It is separated from the part to be welded to maintain and secure a stable contact state with the main body of the conduit to facilitate the fixing work, simplify the structure of the throttle means, and the pressure detector There is a problem to be solved in terms of realizing downsizing.
SUMMARY OF THE INVENTION An object of the present invention is to provide a pressure detector that can stabilize the positioning of the conduit to the main body and facilitate the fixing operation, and can be miniaturized by devising the structure of the throttle means. is there.

  The pressure detector according to the present invention includes a diaphragm, a receiving member that defines a pressure introducing space in cooperation with the diaphragm, and an end formed in an opening formed in the receiving member. A pressure detector comprising a conduit for introducing a fluid and a pressure detection means for detecting the pressure of the fluid introduced into the pressure introduction space via the diaphragm, wherein the receiving member includes the opening and the pressure introduction A pulsation pressure protection member fixed oppositely on the space side is further provided, and the conduit is fixed to the receiving member in a state where a tip inserted through the opening is in contact with the pulsation pressure protection member. It is characterized by that.

  As described above, the pressure detector according to the present invention simplifies the structure of the pulsation pressure protection member, so that the tip inserted through the opening formed in the reception member is in contact with the pulsation pressure protection member. By fixing, it is not necessary to cut or rib the conduit for positioning the conduit in contact with the receiving member, and the structure for attaching the conduit to the receiving member is simplified. In addition, a simple structure of the pulsation pressure protection member can provide a pulsation prevention function and provide a miniaturized pressure detector.

FIG. 1 is a cross-sectional view of an essential part showing an embodiment of a pressure detector according to the present invention. FIG. 2 is a bottom view of the pressure detector shown in FIG. 1 as viewed in the longitudinal direction of the conduit. FIG. 3 is a cross-sectional view of the pressure detector shown in FIG. FIG. 4 is a cross-sectional view of another embodiment of the pressure detector according to the present invention cut along the same cut surface as in FIG. FIG. 5 is a cross-sectional view of still another embodiment of the pressure detector according to the present invention cut along the same cut surface as in FIG. FIG. 6 is a longitudinal sectional view showing an example of a conventional pressure sensor.

  Hereinafter, embodiments of a pressure detector according to the present invention will be described with reference to the accompanying drawings.

  The basic configuration of an example of the pressure detector according to the present invention is equivalent to the structure of the pressure detector shown in FIG. That is, as shown in FIG. 6, the pressure sensor 100 includes a pressure detection unit 110 that includes a pressure detection element 41 therein and a fluid inflow pipe 11 serving as a conduit for introducing pressure, and covers the pressure detection unit 110. A connector connection portion 120 that accommodates a substrate 45 and lead wires 47 connected to the pressure detection element 41 is provided.

  The pressure detection unit 110 includes a base 1, a receiving member 2 disposed so as to face the base 1, and a diaphragm 3 sandwiched between the base 1 and the receiving member 2. The receiving member 2 plays a role as a flow tube connecting member to which the fluid inflow tube 11 is connected at the center. Between the base 1 and the diaphragm 3, a pressure receiving space 31 in which oil is enclosed is formed. The pressure detection element 41 is attached to the base 1 while being immersed in oil in the pressure receiving space 31. The receiving member 2 cooperates with the diaphragm 3 to form a pressurizing space 12 as a pressure introducing space between the receiving member 2 and the diaphragm 3. Since the fluid inflow pipe 11 communicates with the pressurization space 12, fluid pressure is introduced into the pressurization space 12 through the fluid inflow pipe 11. The base 1, the receiving member 2, and the diaphragm 3 are preferably made of, for example, stainless steel.

  The base 1 is formed in a lid shape having a flange 1a at the periphery, and the pressure detection element 41 is attached to the inner surface of the top wall 1b of the lid. The receiving member 2 is formed in a dish-like shape that bulges outward as viewed from the pressurizing space 12 side, and its central part corresponds to a dish-like bottom part, and an opening 2b is formed in the bottom part. Yes. As will be described in detail later, the fluid inflow pipe 11 is brazed and fixed to the opening 2b. The receiving member 2 includes a flange portion 2a that rises from the bottom toward the periphery thereof and is flat. The base 1 and the receiving member 2 are provided with a diaphragm 3 between the flange portion 1a and the flange portion 2a. The diaphragm 3 is held by sandwiching the outer peripheral edge 3a. These three members are simultaneously welded by laser welding 4 or the like at the outer peripheral edge portion where the outer peripheral edge portion 3 a of the diaphragm 3 is exposed, and are integrally connected and fixed as the pressure detection unit 110.

  In the top wall 1 b of the base 1, a filling hole 20 formed through the top wall 1 b for oil filling is sealed with a ball 21. The semiconductor pressure detecting element 41 can be a piezo element. A piezo element is a kind of ferroelectric substance and is also called a piezoelectric element, and is an element having a characteristic of generating a voltage when a force such as vibration or pressure is applied, and conversely expanding and contracting when a voltage is applied. The semiconductor pressure detection element 41 is connected to the substrate 45 through a lead pin 43 extending through a through hole 42 formed in the base 1. The through hole 42 of the base 1 is sealed by a hermetic seal 44 so that there is no oil leakage. The substrate 45 is attached to the connector 46, and the pressure signal is taken out from the lead wire 47 through the substrate 45 and the connector 46.

  The lead pin 43 and the lead wire 47 are offset in a direction intersecting with the drawing direction. Therefore, the connection between the lead pin 43 and the lead wire 47 is made through the substrate 45. With the connection via the substrate 45, the lead wire 47 can be drawn out to the central axis of the pressure sensor 100. That is, handling of the pressure sensor 100 can be facilitated regardless of the installation angle of the pressure sensor 100.

  The connector connecting portion 120 includes a cover 60 that accommodates the pressure detecting portion 110 so as to be fitted to the base 1 from the outside and cover the side of the receiving member 2. The cover 60 also serves as a connector case that covers the substrate 45 and the connector 46. The cover 60 is a member made of a synthetic resin such as PPE, and the end portion (upper end portion) on the side covering the connector 46 is formed in the small diameter end portion 61 by being reduced in diameter so as to surround the lead wire 47. The end portion side that accommodates the pressure detection unit 110 is formed into a large-diameter end portion 63 that has a large inner diameter and extends in a cylindrical skirt shape.

  On the inner peripheral side of the small-diameter end portion 61 of the cover 60, a circumferential protruding portion 62 that protrudes inward is formed so as to be prevented from coming off when the adhesive is filled as will be described later.

  In the cover 60, an annular step 64 having substantially the same diameter as the outer diameter of the base 1 is formed on the inner peripheral side of the large-diameter end 63. The base 1 is an annular corner 1c which is an outer diameter corner. Are mounted so as to be fitted and seated on the annular step 64. On the opening side of the annular stepped portion 64 (inside the large-diameter end portion 63), a cylindrical inner peripheral surface 63a having a larger diameter than the outer diameter of the base 1 is provided. Between this cylindrical inner peripheral surface 63a and the outer peripheral surface 1d of the base 1 and the flange 2a at the peripheral edge of the receiving member 2, an annular gap 65 for the adhesive described later is formed over the entire circumference. . The annular gap 65 is enlarged on the opening side of the large-diameter end portion 63 by the annular lower surface 2 c and the outer tapered peripheral surface 2 d of the receiving member 2 and the inclined end surface 63 b of the large-diameter end portion 63.

  An internal space of the cover 60 is defined by a base 1 inserted into the cover 60 and a first space 51 is formed extending from the top wall 1 b of the cover 1 toward the small diameter end portion 61. The lead pin 43, the substrate 45, the connector 46, and the lead wire 47 (portion located in the small diameter end portion 61) are accommodated in the first space 51. The first space 51 is filled with a first adhesive 71, which is an adhesive made of an epoxy resin, having high adhesion to the cover 60 and the lead wire 47 and high elasticity, and then cured. Since the first adhesive 71 fills the first space 51 so that the lead pins 43, the substrate 45, the connector 46, and the lead wire 47 are embedded, the first adhesive 71 has a sealing function for parts such as the substrate 45 and the connector 46. Play. The first adhesive 71 is bonded to the inner surface of the cover 60 and the lead wire 47 with high adhesiveness.

  The small-diameter end portion 61 is reduced in diameter in the direction in which the lead wire 47 is drawn out, and the small-diameter end portion 61 is formed with a protruding portion 62 that protrudes into the first space 51 on the inner periphery. The end portion 61 and the protruding portion 62 exert a retaining action on the first adhesive 71 that is a filler. In this way, the first adhesive 71 is prevented from peeling off from the internal space 50 and coming out of the cover 60, and the lead wire 47 can be securely fixed to the cover 60 and further airtight can be secured.

  If the first adhesive 71 adheres the base 1 and the cover 60 in the annular step portion 64 of the cover 60 to which the base 1 is fitted, the fixing strength of the pressure detection unit 110 is further increased and the airtightness is increased. To enhance the sealing effect against liquid intrusion from the outside.

  A second space 52 including an annular gap 65 is formed between the fluid inflow pipe 11 side of the pressure detection unit 110 and the large-diameter end portion 63 of the cover 60. That is, the annular gap 65 has an outer peripheral surface 1d of the base 1 of the pressure detection unit 110, a peripheral surface 2e of the flange 2a of the receiving member 2 welded to the base 1, and a large-diameter end facing the peripheral surfaces 1d and 2e. This is a relatively narrow annular space formed between the cylindrical inner peripheral surface 63a of the portion 63. The second space 52 can include an open space 66 that extends from the annular gap 65 toward the outside of the end surface. The open space 66 is a space that is continuous with the annular gap 65, and includes an annular lower surface 2 c that is continuous with the peripheral surface 2 e of the flange portion 2 a of the receiving member 2, an outer tapered peripheral surface 2 d that is continuous with the annular lower surface 2 c, and a large-diameter end portion 63. It is sandwiched between the opening end side portion of the cylindrical inner peripheral surface 63a and the inclined end surface 63b continuous therewith, and expands toward the opening side.

  The second space is filled with a second adhesive 72, which is a silicon-based or urethane-based adhesive that has high adhesion to the receiving member (flow tube connecting member) 2 made of stainless steel and the base 1, and high elasticity. Is done. The second space 52 is filled with the cylindrical inner peripheral surface 63a of the large-diameter end 63 and the outer surface of the base 1 constituting the pressure detection unit 110 of the cover 60 and the receiving member 2 as the flow tube connecting member. When the adhesive 72 is bonded and hardened, the fixing strength of the pressure detection unit 110 with respect to the base 1 and the airtightness that seals the fitting gap between the pressure detection unit 110 and the cover 60 are further enhanced. In addition, the second adhesive 72 has a sealing action that prevents intrusion of liquid or the like from the second space 52 side to the first space 51 side.

  The fluid inflow pipe 11 as a conduit is fixed to the receiving member 2 by using a pulsation preventing plate 80 as a pulsation pressure protecting member as shown in FIGS. That is, the pulsation pressure protection member is a plate member that is fixed to the center bottom wall of the receiving member 2 around the opening 2b and is formed in an inverted dish shape toward the opening 2b. The pulsation preventing plate 80 functions as a throttle means for the fluid flowing through the fluid inflow pipe 11, and includes a central portion 81 in which a throttle hole 84 described later is formed, and an annular fixed portion 82 that extends around the central portion 81. By providing an inclined portion 83 that bends and connects the annular fixed portion 82 with respect to the central portion 81, the whole is formed into a dish-shaped disk.

  A plurality of throttle holes 84 having a smaller diameter than the inner diameter of the body inflow tube 11 are formed in the central portion 81 to provide a throttle function. In this example, as shown in FIG. 2, the throttle hole 84 is a small hole having a diameter approximately one third of the inner diameter of the body inflow pipe 11, and the fluid inflow pipe 11 is inserted therein. A total of three pieces are separated at an angle of 120 degrees so as to be evenly arranged around the center within the region corresponding to the flow path of the fluid inflow pipe 11 inside the annular portion with which the tip 11a abuts. Is formed. The pulsation preventing plate 80 is fixed to the receiving member 2 in advance by fixing an annular fixing portion 82 to the inner surface of the receiving member 2 by laser welding 85 or the like.

  The fluid inflow tube 11 is inserted into the receiving member 2 to which the pulsation preventing plate 80 is fixed in advance until the one end portion 11a of the fluid inflow tube 11 enters the opening 2b and the tube end surface 11b hits the central portion 81 of the pulsation preventing plate 80. The fluid inflow pipe 11 is a copper pipe, and the receiving member 2 is made of stainless steel. The fluid inflow tube 11 is fixed by brazing 86 between the outer peripheral surface of the fluid inflow tube 11 and the edge portion of the opening 2b with respect to the receiving member 2 in a state where the tube end surface 11b abuts against the pulsation preventing plate 80. Is done.

  The pulsation preventing plate 80 exerts a squeezing action in which the throttle hole 84 squeezes the fluid flowing therethrough and reduces pressure fluctuations such as pulsation pressure and impact pressure transmitted through the fluid inflow pipe 11. 3 can be protected. Further, the fluid inflow pipe 11 is fixed to the receiving member 2 by the brazing 86 in a state in which the pipe end surface 11b of the inserted one end portion 11a abuts against the pulsation preventing plate 80, so that a positioning rib is not used. Also, the height for brazing can be uniquely determined. Therefore, the fluid inflow pipe 11 which is a pressure introduction pipe can be attached on the basis of the pulsation preventing plate 80, and labor and cost increase such as processing of a step portion and a rib to the fluid inflow pipe 11 can be avoided. .

  FIG. 3 is a cross-sectional view of the pressure detector shown in FIG. As shown in FIG. 3, the receiving member 2 has an outermost contour A (that is, an outermost portion of the flange portion 2a), an inner contour B of the flange portion 2a, and an outer contour C of the dish-shaped bottom portion. It is shown. For the pulsation prevention plate 80, the outermost contour D (that is, the outside of the fixed portion 82), and the welded portion E as an annular region shown hatched in the fixed portion 82 as described as the laser welding 85, An inner contour (boundary between the fixed portion 82 and the inclined portion 83) F of the fixed portion 82 and an outer contour (boundary between the central portion 81 and the inclined portion 83) G of the central portion 81 are shown. Since an annular space 87 is formed between the peripheral edge portion of the opening 2b in the dish-shaped bottom of the receiving member 2, the one end portion 11a of the fluid inflow tube 11, and the inclined portion 83 of the pulsation preventing plate 80, The flow of brazing material when brazing 86 is stabilized.

  Another embodiment of a pressure detector according to the present invention is shown in FIG. FIG. 4 shows another structure of the pulsation preventing plate, and is a cross-sectional view cut along the same cut surface as in FIG. The pulsation prevention plate 90 shown in FIG. 4 is the same as the structure and parts shown in FIG. 3 because there is no difference from the structure shown in FIG. 3 except for the shape of the throttle hole formed in the central portion 81. The description will be omitted by attaching the reference numerals. The throttle hole 91 of the pulsation preventing plate 90 is formed as one central hole in the central portion of the central portion 81.

  Yet another embodiment of a pressure detector according to the present invention is shown in FIG. FIG. 5 shows still another structure of the pulsation preventing plate, and is a cross-sectional view cut along the same cut surface as in FIG. Also in the pulsation preventing plate 95 shown in FIG. 5, there is no difference from the structure shown in FIG. 3 except that the shape of the throttle hole formed in the central portion 81 is different. The repetitive explanation is omitted by giving the same reference numerals. In the throttle hole 96 of the pulsation preventing plate 95, a hole row 98 in which a plurality of fine holes 97 are arranged in a row becomes a plurality of rows (in the case of illustration, eight rows evenly distributed in the circumferential direction), The central portion 81 is formed so as to extend in the radial direction from the central portion.

  In the above description of the embodiment, an example of a pressure sensor has been shown, but this structure can also be applied to a pressure switch. In the case of a pressure switch, as shown in Patent Document 2, the vertical movement of the pressure receiving diaphragm 3 may be transmitted to a rod-shaped body, and the contact point may be opened and closed by the rod-shaped body.

DESCRIPTION OF SYMBOLS 1 Base 1a Eave part 1b Top wall 1c Annular corner | angular part 1d Outer peripheral surface 2 Receiving member (flow pipe connection member) 2a Eave part 2b Opening 2c Annular lower surface 2d Outer taper peripheral surface 3 Diaphragm 3a Outer peripheral part 4 Laser welding 11 Fluid inflow pipe (Conduit) 11a One end 11b Pipe end surface 12 Pressurization space (pressure introduction space)
20 Filling hole 21 Ball 31 Pressure receiving space 41 Semiconductor pressure detecting element 42 Through hole 43 Lead pin 44 Hermetic seal 45 Substrate 46 Connector 47 Lead wire 51 First space 52 Second space 60 Cover 61 Small diameter end portion 62 Projection portion 63 Large diameter end portion 63a Cylindrical inner peripheral surface 63b Inclined end surface 64 Annular step portion 65 Annular gap 66 Cylindrical inner peripheral surface 71 First adhesive 72 Second adhesive 80 Pulsation prevention plate 81 Central portion 82 Fixed portion 83 Inclined portion 84 Aperture hole 85 Laser Welding 86 Brazing 90 Pulsation prevention plate 91 Restriction hole (center hole)
95 Pulsation prevention plate 96 Restriction hole (small hole)
97 Fine hole 98 Hole array 99 Rib 100 Pressure sensor 110 Pressure detection part 120 Connector connection part

Claims (6)

Diaphragm,
A receiving member that cooperates with the diaphragm to define a pressure introduction space therein;
A conduit for introducing a fluid into the pressure introduction space by inserting one end into an opening formed in the receiving member;
A pressure detector comprising pressure detection means for detecting the pressure of the fluid introduced into the pressure introduction space via the diaphragm;
The receiving member further includes a pulsation pressure protection member fixed opposite to the opening and the pressure introduction space side,
The pressure detector according to claim 1, wherein the conduit is fixed to the receiving member in a state where a distal end inserted through the opening is in contact with the pulsation pressure protecting member. The pressure detector according to claim 1.
The receiving member has a bottom portion in which the opening is formed, and a flat flange portion that rises from the bottom portion toward the periphery thereof and holds the peripheral edge portion of the diaphragm, and is viewed from the pressure introduction space side. A pressure detector, characterized by being formed in a dish-like shape that bulges outward. The pressure detector according to claim 1 or 2,
The pulsation pressure protection member is a pulsation prevention plate fixed to the bottom wall of the receiving member around the opening and formed in an inverted dish shape toward the opening. The pressure detector according to claim 3.
The pressure detector is characterized in that the fixed height of the conduit by brazing or the like to the receiving member is determined by the distance from the opening of the pulsation preventing plate. The pressure detector according to claim 3.
The pulsation prevention plate is a throttle for fluid flowing between the conduit and the pressure introducing space in an area corresponding to the flow path of the conduit, inside the annular portion where the tip into which the conduit is inserted contacts. A pressure detector, characterized in that a throttle hole is formed. The pressure detector according to claim 5.
The throttle hole may be a single central hole formed at the center of the annular portion, small holes formed in a manner that is uniformly arranged around the center of the annular portion, or a plurality of rows from the center of the annular portion. A pressure detector characterized by being a plurality of fine holes that extend radially and are arranged in the longitudinal direction in each row.

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