JP5900176B2 - Physical quantity detection device - Google Patents

Description

  The present invention relates to a physical quantity detection device that detects a physical change.

  As a conventional physical quantity detection device, for example, a pressure sensor that is attached to a surge tank of an internal combustion engine for a vehicle and outputs an electrical signal corresponding to the pressure in the surge tank is known. It is grounded (see, for example, Patent Document 1).

  Specifically, the wiring member for the ground-side electrical signal in the pressure sensor is electrically connected to the metal case via the feedthrough capacitor and the metal cover. Further, the case is screwed to the surge tank so that the body is grounded.

Japanese Patent No. 4049109

  However, the conventional pressure sensor requires a metal cover to electrically connect the feedthrough capacitor and the case, and there is a problem that it is difficult to reduce the size and cost.

  The present invention has been made in view of the above points, and it is an object of the present invention to eliminate the need for a metal cover and facilitate the connection work between a ground terminal and a metal case.

  In order to achieve the above object, according to the first aspect of the present invention, a circuit chip (50) for generating and outputting an electrical signal corresponding to a physical quantity is provided, and a ground signal wiring for a ground-side electrical signal output from the circuit chip. A physical quantity detection device whose member is grounded via a capacitor (51), wherein the circuit chip and the capacitor are mounted on a plate-like metal lead frame (52), and the circuit chip, the capacitor and the lead frame are molded. Mold IC (5) sealed with resin, and cylindrical metal case (1, 2) that is attached to the attached member and grounded via the attached member, and that accommodates the mold IC inside The lead frame has a ground terminal (522) that is connected to the capacitor and protrudes from the mold IC, and the ground terminal is itself Characterized in that in contact with the casing by an elastic restoring force.

  According to this, since the ground terminal provided on the lead frame is brought into direct contact with the case, a metal cover can be dispensed with. In addition, since the ground terminal and the case are connected without using welding or a conductive adhesive, the connection work can be facilitated.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is sectional drawing which shows the structure of the physical quantity detection apparatus which concerns on 1st Embodiment of this invention. It is II-II sectional drawing of FIG. It is a perspective view which shows the state before bending the ground terminal of the mold IC of FIG. It is a figure which shows the state after bending the ground terminal of the mold IC of FIG. It is sectional drawing which shows the structure of the physical quantity detection apparatus which concerns on 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A first embodiment of the present invention will be described.

  The physical quantity detection device according to the present embodiment is attached to a brake hydraulic pressure control device that controls the brake hydraulic pressure of an automobile, and detects the brake hydraulic pressure as a physical quantity. The brake fluid pressure control device corresponds to the attached member of the present invention and is grounded.

  As shown in FIGS. 1 and 2, the physical quantity detection device includes a first case 1 formed of a conductive metal into a bottomed cylindrical shape. On the outer periphery of the first case 1, there is formed a screw portion 10 that is screwed into the brake fluid pressure control device. The first case 1 includes a pressure introducing hole 11 having an opening at one end. On the bottom side of the first case 1, that is, on the side opposite to the opening of the pressure introduction hole 11, a thin portion 12 is formed that deforms in accordance with the pressure of the brake fluid guided through the pressure introduction hole 11.

  The second case 2 is formed in a cylindrical shape with a conductive metal, and is joined to the first case 1 by welding. The first case 1 and the second case 2 constitute a case of the present invention.

  A gauge 3 whose resistance value changes according to the deformation of the thin portion 12 (in other words, according to the brake fluid pressure) is attached to the thin portion 12 of the first case 1.

  The pedestal 4 is formed in a substantially cylindrical shape with a resin having a high electrical insulating property, and is bonded to the first case 1 by adhesion so as to surround the thin portion 12 and the gauge 3.

  A rectangular parallelepiped mold IC 5 is disposed in the second case 2. The mold IC 5 includes a circuit chip 50 that generates and outputs an electrical signal corresponding to pressure based on a change in resistance value of the gauge 3, a chip capacitor 51, and a lead frame 52 made of a copper alloy plate material that is a good electrical conductor. ing.

  A ground signal wiring member for a ground-side electrical signal output from the circuit chip 50 is electrically connected to a ground terminal described later via a chip capacitor 51. A part of the lead frame 52 constitutes a ground signal wiring member.

  After the circuit chip 50 and the chip capacitor 51 are mounted on the lead frame 52, the circuit chip 50, the chip capacitor 51, and the lead frame 52 are sealed with a mold resin layer 53 made of a resin having high electrical insulation. . A relay terminal 520, a signal output terminal 521, and a ground terminal 522 that are part of the lead frame 52 protrude from the mold resin layer 53.

  One end of the relay terminal 520 is molded on the pedestal 4 so that the pedestal 4 and the molded IC 5 are integrated. Then, wire bonding is performed between the relay terminal 520 and the gauge 3, and the relay terminal 520 and the gauge 3 are electrically connected by the wire 6.

  A connector terminal 7 for connecting to the external connector is joined to the signal output terminal 521 by welding. The opening of the second case 2 on the side opposite to the first case is closed by a disk-shaped cap 8 made of a resin having high electrical insulation, and the connector terminal 7 has a hole formed in the cap 8. It penetrates and protrudes to the outside. An annular plate 9 that supports the cap 8 is joined to the end of the second case 2 on the side opposite to the first case by welding.

  As shown in FIGS. 1 to 4, two ground terminals 522 are arranged on two opposing surfaces among the four surfaces opposing the inner peripheral surface of the second case 2 in the mold IC 5. Further, the two ground terminals 522 arranged on one surface of the mold IC 5 are shifted in the axial direction of the second case 2 (hereinafter referred to as the case axial direction).

  As shown in FIGS. 2 and 4, the four ground terminals 522 extend in different directions from the mold IC 5 toward the inner peripheral surface of the second case 2 when viewed along the case axial direction. The tip of the ground terminal 522 has an arc shape when viewed along the case axial direction. The four ground terminals 522 are configured such that the outer peripheral surface of the arc-shaped portion is in contact with the inner peripheral surface of the second case 2 by its own elastic restoring force.

  Next, a procedure for assembling the physical quantity detection device will be described.

  First, the gauge 3 is attached to the thin portion 12 of the first case 1. In parallel with this, the mold resin layer 53 of the mold IC 5 and the pedestal 4 are simultaneously molded, and then the connector terminal 7 is joined to the signal output terminal 521 of the mold IC 5 by welding, and four ground terminals 522 are shown in FIG. Bend in a predetermined direction as shown in FIG. At this time, the relay terminal 520 is not bent into an L shape.

  Subsequently, after the base 4 is bonded to the first case 1 by bonding, the relay terminal 520 and the gauge 3 are connected by the wire 6. Subsequently, the relay terminal 520 is bent into an L shape as shown in FIG.

  Subsequently, the ground terminal 522 is deformed by a jig (not shown) so that the circumscribed circle of the four ground terminals 522 is smaller than the inner diameter of the second case 2, and the base 4 and the mold are maintained while maintaining the state. IC5 or the like is inserted into the second case 2.

  Subsequently, the jig is removed, the cap 8 is attached to the connector terminal 7, and the plate 9 is joined to the second case 2 by welding to complete the physical quantity detection device.

  Here, when the jig is removed, the grounding terminal 522 is restored by its own elastic restoring force so that the circumscribed circle of the four grounding terminals 522 becomes large, and the arcuate shape provided at the tip of the grounding terminal 522 is restored. The outer peripheral surface of the part contacts the inner peripheral surface of the second case 2.

  Therefore, when the physical quantity detection device is attached to the brake fluid pressure control device, the ground signal wiring member of the ground side electric signal output from the circuit chip 50 is the chip capacitor 51, the ground terminal 522, the second case 2, the first case 1, and so on. , And the body is grounded via the brake fluid pressure control device.

  Thus, in this embodiment, since the ground terminal 522 provided in the lead frame 52 is brought into direct contact with the second case 2, a metal cover can be dispensed with.

  In addition, since the ground terminal 522 and the second case 2 are electrically connected without using welding or a conductive adhesive, it is possible to facilitate the connection work.

  Furthermore, since a plurality of ground terminals 522 are provided, even if any one of the ground terminals 522 is separated from the second case 2 due to vibration or the like, the contact state between the other ground terminals 522 and the second case 2 is maintained. The

(Second Embodiment)
A second embodiment of the present invention will be described. In the present embodiment, the configuration of the ground terminal 522 is changed, and the other parts are the same as those in the first embodiment. Therefore, only different portions will be described.

  As shown in FIG. 5, in this embodiment, the natural vibration value of each ground terminal 522 is made different by making the length of each ground terminal 522 different. According to this, even when any one of the ground terminals 522 resonates, the other ground terminals 522 do not resonate, so that the contact state between the other ground terminals 522 and the second case 2 is stably maintained.

  Further, instead of varying the length of each ground terminal 522, the width of each ground terminal 522 may be varied to vary the natural vibration value of each ground terminal 522. The width of the ground terminal 522 is a dimension of the ground terminal 522 in the case axis direction.

(Other embodiments)
In each of the above embodiments, a physical quantity detection device that detects pressure is shown, but the present invention can also be applied to a physical quantity detection device that detects physical quantities other than pressure, for example, physical quantities such as yaw rate and acceleration.

  Moreover, each said embodiment can be arbitrarily combined in the range which can be implemented.

1 First Case 2 Second Case 5 Mold IC
50 circuit chip 51 capacitor 52 lead frame 522 ground terminal

Claims (7)

A circuit chip (50) that generates and outputs an electrical signal corresponding to a physical quantity, and a physical quantity detection in which a ground signal wiring member of a ground-side electrical signal output from the circuit chip is grounded via a capacitor (51). A device,
A mold IC (5) in which the circuit chip and the capacitor are mounted on a plate-shaped metal lead frame (52), and the circuit chip, the capacitor and the lead frame are sealed with a mold resin;
A cylindrical metal case (1, 2) that is attached to the attached member and is grounded via the attached member, and that accommodates the mold IC therein,
The lead frame includes a ground terminal (522) connected to the capacitor and protruding from the mold IC,
The physical quantity detection device according to claim 1, wherein the ground terminal is in contact with the case by its own elastic restoring force.   The physical quantity detection device according to claim 1, comprising a plurality of the ground terminals.   The physical quantity detection device according to claim 2, wherein at least one of the plurality of ground terminals is different in length and width.   The plurality of ground terminals extend in different directions from the mold IC toward the inner peripheral surface of the case when viewed along the axial direction of the case. The physical quantity detection device according to 1.   The case includes a first case (1) having a screw portion (10) screwed to the attached member, and a cylindrical second case (2) joined to the first case. The physical quantity detection device according to claim 1, wherein the physical quantity detection device is characterized in that: The case includes a thin portion (12) that deforms according to the pressure inside the member to be attached.
The physical quantity detection device according to any one of claims 1 to 5, wherein a gauge (3) whose resistance value changes according to deformation of the thin portion is joined to the thin portion. The physical quantity detection device according to claim 1, wherein the lead frame is made of copper or a copper alloy .

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