JP2012237612A - Pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensor that allows airtightness of a pressure detection unit to be maintained while allowing improvement in structural vulnerability around an output lead pin.SOLUTION: A pressure sensor 1 comprises: a pressure detection unit 2 having a pressure detection element 21; an output lead pin 33 connected to the pressure detection element and protruding to the outside of the pressure detection unit; and a wiring board 31 having the output lead pin fixed electrically in a connectable manner to an external output lead wire 32. An adjustment lead pin 36 (36B, 36C) connected to the pressure detection element and protruding to the outside of the pressure detection unit is fixed to the wiring board. Since not only the output lead pin but also the adjustment lead pin used for voltage correction and the like is fixed to the wiring board, the strength of the entire structure of the output lead pin, the wiring board and the adjustment lead pin is increased, thereby allowing improvement in structural vulnerability around the output lead pin.

Description

  The present invention relates to a pressure sensor, and more particularly to a liquid-filled pressure sensor in which a liquid is sealed in a pressure-receiving space that houses a pressure detection element.

  Conventionally, a liquid is enclosed in a pressure receiving space in which a pressure detection element is accommodated, and pressure applied from the outside to the pressure detection chamber is transmitted to the pressure detection element via the liquid, so that the pressure detection element responds to the external pressure. Various pressure sensors that output voltage signals have been proposed.

  As an example of the liquid-filled pressure sensor, Patent Document 1 discloses that a pressure transmitted through a barrier diaphragm is detected by a sensor chip (pressure detection element), and the detected pressure is converted into a voltage, so that a disk-shaped positioning is performed. A pressure sensor that outputs to the outside via a plurality of electrode pins (lead pins) arranged concentrically on glass (base) is described.

  In addition, the voltage output from the pressure detection element of the pressure sensor cannot be used as an external output as it is due to manufacturing or component variations, and correction according to the characteristics of the pressure sensor is essential. As described in Patent Document 2, the voltage correction is generally performed by storing correction information in a read-only memory in advance and reading the information stored at the time of pressure measurement to correct the voltage.

  In this case, the lead pin is provided for the voltage correction (hereinafter referred to as “for adjustment”) in addition to the output. The output lead pin is soldered to the wiring board, and the voltage signal from the pressure detection element is transmitted through the wiring board to, for example, the external output lead wire drawn from the center of the pressure sensor. Used exclusively when storing correction information during manufacturing, and is not connected to an external output lead wire. Further, the output lead pins and the adjustment lead pins are usually arranged separately for each group in consideration of the structure of the pressure detection element and the ease of the adjustment work.

JP 2001-41838 A JP-A-62-175631

  However, in the conventional pressure sensor described above, the axis of the output lead pin and the lead wire are misaligned, and therefore, if the output lead pin is pulled in the lead wire direction during manufacture of the pressure sensor, there is a risk of significant deformation. It was. Moreover, although the lead pin is sealed between the through-holes by a hermetic seal, there is a possibility that the hermetic seal itself is broken by the pulling.

  Accordingly, the present invention has been made to solve the above-described problems, and provides a pressure sensor that maintains the airtightness of the pressure detection unit and improves the structural vulnerability around the output lead pin. With the goal.

  In order to achieve the above object, the present invention provides a pressure detection unit having a pressure detection element, an output lead pin connected to the pressure detection element and projecting outside the pressure detection unit, and the output lead pin is an external output In a pressure sensor comprising a wiring board fixed to be electrically connectable to a lead wire for use, an adjustment lead pin connected to the pressure detection element and protruding outside the pressure detection part is fixed to the wiring board. It is characterized by.

  According to the present invention, not only the output lead pin but also the adjustment lead pin used for voltage correction or the like is also fixed to the wiring board, so that the strength of the overall structure of the output lead pin, the wiring board and the adjustment lead pin is increased. It is possible to prevent deformation of the lead pin caused by pulling in the lead wire direction.

  In the pressure sensor, the output lead pin and the adjustment lead pin pass through a member to which the pressure detection element is fixed and project outside the pressure detection unit, and the output lead pin and the adjustment lead pin penetration part. It can be sealed with a hermetic seal. As a result, the hermeticity of the pressure detector can be maintained and the hermetic seal itself can be prevented from being broken.

  Furthermore, in the pressure sensor, the output lead pin and the adjustment lead pin are arranged in a substantially annular shape, and can be positioned on opposite sides of the center of the annular shape. Such an arrangement of the lead pins further effectively prevents the deformation of the lead pins and the destruction of the hermetic seal.

  As described above, according to the present invention, the airtightness of the pressure detection portion of the pressure sensor can be maintained, and the structural vulnerability around the output lead pin can be improved.

It is a figure which shows one Embodiment of the pressure sensor concerning this invention, Comprising: (a) is a longitudinal cross-sectional view, (b) is the AA arrow directional view of (a), Comprising: The state which removed the case Indicates.

  Next, an embodiment for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an embodiment of a pressure sensor according to the present invention. This pressure sensor 1 has a pressure detection element 21 inside, a pressure detection unit 2 to which a fluid inflow part 22 is connected, and a pressure detection. In addition to surrounding the portion 2, a wiring substrate (hereinafter referred to as “substrate”) 31 connected to the pressure detection element 21 and a connector connecting portion 3 that accommodates an external output lead wire 32 are provided.

  The pressure detection unit 2 includes a pressure detection element 21, a base 23, a receiving member 24 disposed to face the base 23, and a diaphragm 25 sandwiched between the base 23 and the receiving member 24. Is provided. Liquid (oil) is sealed in the pressure receiving space 26 between the base 23 and the diaphragm 25. The pressure detection element 21 is fixed to the base 23 inside the pressure receiving space 26. A pressurizing space 27 as a pressure introducing space is formed between the receiving member 24 and the diaphragm 25, and the internal space of the fluid inflow portion 22 communicates with the pressurizing space 27.

  The base 23 is formed in a lid shape, and the pressure detection element 21 is fixed to the lower surface of the base 23. The receiving member 24 is formed in a dish shape with an upper opening, and the fluid inflow portion 22 is brazed and fixed to the central opening. The diaphragm 25 is sandwiched between the flange portion of the base 23 and the flange portion of the receiving member 24, and these three members 23 to 25 are arranged at the outer periphery portion where the outer periphery portion of the diaphragm 25 is exposed. They are welded simultaneously by laser welding or the like and integrated as the pressure detection unit 2. In the pressure receiving space 26, after a liquid (oil) is injected from a filling hole (not shown) formed through the base 23, the filling hole is sealed by a ball 28 on the upper surface of the base 23.

  The pressure detection element 21 is, for example, a piezo element. This piezo element is a kind of ferroelectric substance and is also called a piezoelectric element. When a force such as vibration or pressure is applied, a voltage is generated. When it is added, it expands and contracts.

  The pressure detection element 21 is electrically connected to an output lead pin 33 (33A to 33C) and an adjustment lead pin 36 (36A to 36E) inserted through a through hole 23a formed in the base 23 via a wire 29. The output lead pin 33 is for outputting a voltage signal corresponding to the pressure detected by the pressure detection element 21 to the outside, and the adjustment lead pin 36 is used for voltage correction at the time of manufacture as described above. It is used.

  Further, the output lead pins 33 (33 </ b> A to 33 </ b> C) and two of the five adjustment lead pins 36 (36 </ b> B and 36 </ b> C) have their upper ends fixed to the substrate 31. Three wiring patterns 50 made of metal foil for connecting and fixing the output lead pins 33A to 33C are formed on the surface of the substrate 31, and for fixing the two adjustment lead pins 36B and 36C. Two metal foils 51 are formed.

  The three wiring patterns 50 are formed to connect the output lead pins 33 </ b> A to 33 </ b> C and each of the three external output lead wires 32 connected to the substrate 31 via the connector 34.

  The two metal foils 51 are provided only for fixing the adjustment lead pins 36B and 36C to the substrate 31. Even if each of the adjustment lead pins 36B and 36C is connected to each metal foil 51, each lead pin is provided. 36B and 36C are not connected to other lead pins or external output lead wires, and are electrically disconnected from these.

  As shown in FIG. 1, the output lead pins 33A to 33C and the adjustment lead pins 36A to 36E are arranged on a substantially annular shape with the pressure detection element 21 as the center, and the external output lead wire 32 has a pressure detection. When the element 21 is pulled out in the central axis direction (the central axis direction of the pressure sensor 1), the output lead pins 33A to 33C and the external output lead wire 32 are eccentric, so that they are simply extracted from the substrate 31. If a tensile force or the like is applied to the external output lead wire 32, a lateral stress is applied to the output lead pins 33A to 33C to deform them, and the lead pins 33A to 33C will be described later. The hermetic seal 23b may be destroyed.

  However, as in this embodiment, adjustment lead pins (in the case of this embodiment) located on the opposite side of the output lead pins 33A to 33C with respect to the pressure detection element 21 (in other words, the center of the above-described ring). Are fixed to the substrate 31 so that even if a tensile force or the like is applied to the external output lead wire 32, no lateral stress is applied to the output lead pins 33A to 33C. The hermetic seal 23b surrounding each of the output lead pins 33A to 33C (and the adjustment lead pins 36B and 36C) is not broken.

  Thus, not only the output lead pin 33 but also the adjustment lead pin 36 that originally does not need to be fixed to the substrate 31 is fixed to the substrate 31, which is a feature of the present invention. The strength of the entire structure of the substrate 31 and the adjustment lead pins 36 (36B, 36C) is increased, and the structural vulnerability around the output lead pins 33 can be improved.

  The through hole 23a of the base 23 is sealed so as not to leak liquid (oil) by the hermetic seal 23b after the output lead pin 33 and the adjustment lead pin 36 are inserted. A connector 34 is attached to the substrate 31, and a voltage signal from the pressure detection element 21 is taken out from the external output lead wire 32 through the output lead pin 33, the substrate 31 and the connector 34.

  The connector connecting portion 3 includes a cover 35 that accommodates the pressure detecting portion 2 so as to be fitted to the base 23 from the outside and cover the side of the receiving member 24. The cover 35 also functions as a connector case that covers the substrate 31 and the connector 34. The cover 35 is made of a synthetic resin such as PPE, and the upper end portion that covers the connector 34 is reduced in diameter so as to surround the external output lead wire 32, and the lower end portion side that accommodates the pressure detection unit 2 is It is formed in a large diameter shape extending in a cylindrical skirt shape.

  The cover 35 is formed with an annular step portion 35a having substantially the same diameter as the outer diameter of the base 23 on the inner peripheral side thereof on the large diameter end portion side, and the base 23 is an annular corner portion that is an outer diameter corner portion thereof. In 23c, it is mounted so as to be fitted and seated on the annular step portion 35a.

  The internal space of the cover 35 is partitioned by the base 23 inserted in the cover 35 to form a space 41. The output lead pin 33, the adjustment lead pin 36, the substrate 31, the connector 34, and the external output lead wire 32 are accommodated in the space 41. The space 41 is filled with an adhesive such as urethane resin having high adhesiveness and elasticity with the cover 35 and the external output lead wire 32, and then cured. Since this adhesive is filled in the space 41 so that the output lead pin 33, the adjustment lead pin 36, the substrate 31, the connector 34, and the external output lead wire 32 are embedded, components such as the substrate 31 and the connector 34 are provided. Provides a sealing function.

  In addition, it takes a certain amount of time to cure this adhesive, but even if a tensile force is applied to the external output lead wire until the adhesive is cured, The hermetic seal 23b is prevented from being broken. Of course, even after the adhesive is cured, the effect of preventing deformation and destruction is achieved.

  The pressure sensor 1 having the above configuration changes the pressure of the pressurized space 27 due to a change in the pressure of the fluid flowing in from the fluid inflow portion 22 and deforms the diaphragm 25. Due to the deformation of the diaphragm 25, the pressure of the liquid (oil) sealed in the pressure receiving space 26 changes, and the pressure change propagates to the pressure detection element 21. The pressure detected by the pressure detection element 21 is converted into a voltage, and at that time, a predetermined voltage correction according to the characteristics of the pressure sensor 1 is performed. The corrected voltage signal is transmitted to the external output lead wire 32 via the output lead pin 33, the substrate 31 and the connector 34.

  In the above embodiment, two of the five adjustment lead pins 36 (36B, 36C) are fixed to the substrate 31, but only one of the adjustment lead pins 36B, 36C is fixed to the substrate 31. Alternatively, three or more of the five adjustment lead pins 36 may be fixed to the substrate 31.

DESCRIPTION OF SYMBOLS 1 Pressure sensor 2 Pressure detection part 3 Connector connection part 21 Pressure detection element 22 Fluid inflow part 23 Base 23a Through-hole 23b Hermetic seal 23c Annular corner | angular part 24 Receiving member 25 Diaphragm 26 Pressure receiving space 27 Pressurizing space 28 Ball 29 Wire 31 Wiring board 32 External output lead wire 33 (33A to 33C) Output lead pin 34 Connector 35 Cover 35a Annular step 36 (36A to 36E) Adjustment lead pin 41 Space 50 Wiring pattern 51 Metal foil

Claims (3)

A pressure detection unit having a pressure detection element;
An output lead pin connected to the pressure detection element and projecting outside the pressure detection unit;
In the pressure sensor, the output lead pin includes a wiring substrate fixed to be electrically connectable to the external output lead wire,
An adjustment lead pin connected to the pressure detection element and protruding to the outside of the pressure detection unit is fixed to the wiring board.   The output lead pin and the adjustment lead pin pass through a member to which the pressure detection element is fixed and project outside the pressure detection unit, and the output lead pin and the adjustment lead pin penetration portion are sealed with a hermetic seal. The pressure sensor according to claim 1, wherein the pressure sensor is stopped.   3. The pressure sensor according to claim 1, wherein the output lead pin and the adjustment lead pin are arranged in a substantially annular shape, and are positioned on opposite sides with respect to the center of the annular shape.

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