JPH045534A - Gasket type pressure sensor and its manufacture - Google Patents

Abstract

PURPOSE:To facilitate the automation of assembling operation by forming main body metal fittings by drawing, and fixing a packing, an electrode plate, a piezoelectric ceramic plate, presser metal, and a lead wire by caulking the ends of the inner peripheral cylinder and outer peripheral cylinder of the main body metal fittings. CONSTITUTION:A main body metal fitting material 150 is formed of an annular part 111, a bottom part 110 with an outward projection part 121, the inner peripheral part 130, and the outer peripheral part 140 by drawing a metallic thin plate which is punched in a specific shape. Then the annular part 111 is provided with the annular plate type packing 2 made of an electric insulator, an annular electrode plate 3 to which the lead wire 6 arranged at the projection part 121 is connected, the annular piezoelectric ceramic plate 4, the annular presser metal 5, the electrode plate 3, and the piezoelectric ceramic plate 4, and an insulating tube 101 is fitted onto the inner peripheral cylinder part 130 while insulated from the main body metal fitting material 150. The ends of the inner peripheral cylinder 130 and outer peripheral cylinder 140 are caulked to fix the packing 2, electrode plate 3, piezoelectric ceramic plate 4, presser metal 5, and lead wire 6, and an electric insulating seal material 7 is packed inside.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a gasket-type pressure sensor attached to a gasket mounting portion of a spark plug for measuring pressure changes in a combustion chamber of an internal combustion engine.

[Prior Art] As shown in FIG. 5, a conventional gasket type pressure sensor 2
00, a hole 211 for taking out the electrode wire 201 is formed on the outer peripheral wall surface of the hollow annular metal shell 210 having a rectangular cross section.
A cap 220 is provided by brazing a pipe so as to communicate with this hole. Inside the metal shell 210 is a ring-shaped center electrode plate 230 to which the tip of the electrode wire 201 is connected;
Two annular piezoelectric ceramic plates 24 stacked on both sides
0.250 and an annular outer electrode plate 260.270 superimposed on the outside. The base 220 has a core wire 310 connected to the rear end of the electrode l11201.
is wrapped with an insulating coating 320, and the outside is further covered with a metal mesh 330.
A lead wire 300 wrapped in is connected. Main metal fittings 2
10 and the inside of the base 220 are filled with silicone rubber 280.

[Problems to be Solved by the Invention] In recent years, this type of gasket-type pressure sensor has tended to be installed in each cylinder of the engine as a knocking sensor in automobiles, and mass production and cost reduction are desired. The gasket type pressure sensor 200 has the following problems in mass production.

(A) Brazing the cap 220 to the metal shell 210;
The work of passing the electrode 11201 into the bent pipe is as follows:
This is a manual process, requires skill, and is difficult to automate, resulting in poor productivity.

(b) Cost increases due to the large number of parts.

An object of the present invention is to provide a gasket-type pressure sensor that can reduce the number of parts, easily automate assembly, excel in mass production, and be manufactured at low cost, and a method for manufacturing the same.

[Means for Solving the Problems] In order to achieve the above object, the present invention employs the following configuration.

1) A metal shell that is integrally formed by drawing a thin metal plate punched into a predetermined shape and has a hollow annular main body and a cylindrical mouthpiece that communicates with the main body, and an electric wire fitted into the main body. an annular plate packing made of an insulating material; and an annular electrode plate that is overlapped with the packing, is fitted into the metal shell so as to be insulated, and is connected to a core wire of a lead wire inserted into the mouthpiece. , an annular piezoelectric ceramic plate superimposed on the annular electrode plate and fitted so as to be insulated from the metal shell; and an annular piezoelectric ceramic plate superimposed on the piezoelectric ceramic plate and fitted so as to be electrically connected to the metal shell. the core wire, an insulating coating covering the outer periphery of the core wire, and a metal mesh surrounding the outer periphery of the core wire, the core wire being connected to the annular electrode plate, and the metal mesh being connected to the base portion. A gasket type pressure sensor comprising a lead wire inserted into the mouthpiece and an electrically insulating sealing material filled in the metal shell.

2) By drawing a gold NL thin plate punched into a predetermined shape, a bottom portion having an annular portion and an outwardly protruding portion, an inner circumferential cylindrical portion-1 extending from the inner circumference thereof, and the tip of the protruding portion are formed. forming a metal shell consisting of an outer peripheral cylindrical portion extending in the same direction as the inner peripheral cylindrical portion from the outer periphery of the bottom portion; An annular electrode plate, an annular piezoelectric ceramic plate, and an annular presser foot to which lead wires are connected are fitted so that the electrode plate and the piezoelectric ceramic plate are insulated with respect to the metal shell, and a core wire is attached to the protruding portion. , has an insulating coating covering its outer periphery, and a metal mesh further surrounding its outer periphery, the core wire is fitted with a lead wire connected to the annular electrode plate, and the ends of the inner circumferential tube and outer circumferential tube of the metal shell are caulked to A method for manufacturing a gasket-type pressure sensor, which fixes a gasket, an electrode plate, a piezoelectric ceramic plate, a presser foot, and a lead wire, and also fills the inside with an electrically insulating sealant.

[Operations and Effects of the Invention] In the gasket type pressure sensor of the present invention, the annular main body portion and the mouth portion are integrally formed by press molding of sheet metal, so that the number of parts can be reduced.

By drawing a thin metal plate punched into a predetermined shape, a bottom part having an annular part and an outwardly protruding part, an inner cylindrical part extending from the inner periphery of the bottom part, and the bottom part excluding the tip of the protruding part are obtained. A metal shell is formed of an outer circumferential tube extending from the outer circumference in the same direction as the inner circumferential tube. This makes it easy to automate the assembly process.

Due to the above, it has excellent mass productivity and can be manufactured at low cost.

[Example] The gas get type pressure sensor 100 of the present invention is shown in FIGS. 1 to 3.
An explanation will be given based on an example shown in the figure.

The pressure sensor 100 is integrally formed by drawing a thin metal plate punched into a predetermined shape, and includes a hollow annular main body 11 having a rectangular cross section, and a cylindrical or polygonal cylindrical body communicating with the main body 11. The main metal fitting 1 is comprised of a cap part 12.

Inside the main body portion 11, in contact with one end plate 11a,
An annular plate packing 2 made of an electrically insulating material and having a radial groove 21 on the lower surface shown in the figure is fitted into the packing 2.
An annular electrode plate 3 is insulated and overlapped with the metal shell in contact with the metal shell.

In this embodiment, the packing 2 is made of a ceramic sintered body mainly made of alumina, but it may also be made of other inorganic materials such as ceramics or resins with good heat resistance.
Further, the electrode plate 3 is formed by punching a stainless steel or copper-based metal plate, and is welded and connected to the core wire of a lead wire, which will be described later, inserted into the base portion 12. The groove 21 is
This is to ensure space for housing the lead wires.
It may be provided on the side of the electrode plate 3 or on both sides, and can be omitted by connecting the lead wire on the outer peripheral surface of the electrode plate. An annular piezoelectric ceramic plate 4 is stacked on the annular electrode plate 3 so as to be insulated from the metal shell. The electrode plate 3 and the piezoelectric ceramic plate 4 are insulated by an insulating tube 101 made of fluorocarbon (Teflon) resin and silicone rubber fitted to the inner circumferential wall 11b of the main body. Although this insulating tube 101 is not essential to the present invention, the above-mentioned insulation can be easily obtained during the assembly process by using this insulating tube 101. An annular presser foot 5 is stacked on the piezoelectric ceramic plate 4 so as to contact and electrically connect to the other end plate 11c of the main body portion 11. The presser foot 5 is formed by punching a stainless steel or copper metal plate.

The lead wire 6 consists of the core wire 61, an insulating coating 62 that covers the outer periphery of the core wire, and a metal mesh 63 that further covers the outer periphery of the core wire 61. The lead wire 6 is inserted into the base 12, the core wire 61 is welded and connected to the annular electrode plate 3, and the metal mesh 63 is pressure-welded to the base.

The interior of the main body portion 11 and the cap portion 12 of the metal shell 1 is filled with an electrically insulating sealant such as silicone rubber as a sealant in order to maintain airtightness and watertightness.

The sealing material is preferably silicone-based or fluorine-based rubber or resin, which has excellent heat resistance.

Next, a method for assembling this gasket type pressure sensor will be explained.

a) As shown in FIG. 3, a bottom part 110 having an annular part 111 and an outwardly protruding part 121 and an inner circumferential cylindrical part extending from the inner periphery are formed by drawing a thin metal plate punched into a predetermined shape. 130, and an outer circumferential cylindrical portion 140 extending in the same direction as the inner circumferential cylindrical portion 130 from the outer periphery of the bottom excluding the tip of the protruding portion.

At this time, in order to facilitate the subsequent drawing process, the outer circumferential cylindrical portion 14
A notch 141 is provided at the communication portion between the annular portion of 0 and the protruding portion. As the thin metal plate, a stainless steel plate or a mild steel plate with anti-rust plating is used. Further, the protrusion that becomes the mouthpiece after molding has a U-shaped cross section.

b) Fit the following items into this metal shell material 150.

The annular portion 111 is provided with an annular plate packing 2 made of an electrically insulating material, an annular electrode plate 3 to which a lead wire 6 disposed on the protruding portion 121 is connected, an annular piezoelectric ceramic plate 4, and an annular presser foot. 5. The electrode plate 3 and the piezoelectric ceramic plate 4 are fitted with an insulating tube 101 on the inner peripheral cylindrical portion 1'30 so as to be insulated from the metal shell material 15O.

The protrusion 121 has a core wire 61, an insulating coating 62 covering the outer periphery of the core wire, and a metal mesh 63 surrounding the outer periphery of the core wire 61, and the core wire 61 has a lead wire 6 connected to the annular electrode plate 3.
C) The ends of the inner cylinder 130 and outer cylinder 140 of the metal shell are caulked to fix the gasket 2, electrode plate 3, piezoelectric ceramic plate 4, presser foot 5, and lead wire 6,
An electrically insulating sealing material 7 is filled inside.

[Modification] As shown in FIG. 4, it is also possible to bend the base portion 12 with respect to the main body portion 11.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view of a gasket type pressure sensor of the present invention, Fig. 2 is a side view thereof, Fig. 3 is an assembly diagram thereof, and Fig. 4 is a cross section of a gasket type pressure sensor of another embodiment of the invention. FIG. 5 is a sectional view of a conventional gasket type pressure sensor. In the diagram: 1... Metal shell 2... Annular plate packing 3
...Annular electrode plate 4...Annular piezoelectric ceramic plate 5
... Annular presser foot 6 ... Lead wire 7 ... Electrically insulating sealing material 11 ... Main body part 12 ... Mouth part 61 ... Core wire 62 ... Insulation coating 63 ... Metal Net lOO...Gasket type pressure sensor 110.
...Bottom part 111...Annular part 121...Protrusion part 130...Inner circumference cylindrical part 140...Outer circumference cylinder part Fig. 4

Claims (1)

[Scope of Claims] 1) A metal shell that is integrally formed by drawing a thin metal plate punched into a predetermined shape and has a hollow annular main body portion and a cylindrical mouthpiece that communicates with the main body portion; an annular plate packing made of an electrically insulating material fitted into the part; and a ring-shaped plate packing made of an electrically insulating material that is overlapped with the packing, fitted so as to be insulated with respect to the metal shell, and connected to the core wire of a lead wire inserted into the base part. an annular piezoelectric ceramic plate overlaid on the annular electrode plate and fitted in such a manner as to be insulated from the metal shell; and an annular piezoelectric ceramic plate overlaid on the piezoelectric ceramic plate and electrically connected to the metal shell. the core wire, an insulating coating that covers the outer periphery of the core wire, and a metal mesh that further surrounds the outer periphery of the core wire; the core wire is connected to the annular electrode plate; A gasket-type pressure sensor comprising a lead wire connected to and inserted into the mouthpiece, and an electrically insulating sealing material filled in the metal shell. 2) By drawing a thin metal plate punched into a predetermined shape, a bottom portion having an annular portion and an outwardly protruding portion, an inner cylindrical portion extending from the inner periphery of the bottom portion, and the above-mentioned parts excluding the tip of the protruding portion A metal shell is formed with an outer circumferential tube extending from the outer circumference of the bottom in the same direction as the inner circumferential tube, and an annular plate packing made of an electrically insulating material is disposed on the annular portion and on the protruding portion. An annular electrode plate to which a lead wire is connected, an annular piezoelectric ceramic plate, and an annular presser foot are fitted so that the electrode plate and the piezoelectric ceramic plate are insulated with respect to the metal shell, and a core wire, the It has an insulating coating that covers the outer periphery and a metal mesh that further covers the outer periphery, the core wire is fitted with a lead wire connected to the annular electrode plate, and the ends of the inner circumferential cylinder and the outer circumferential cylinder of the metal shell are caulked to form the packing, A method for manufacturing a gasket-type pressure sensor that fixes an electrode plate, piezoelectric ceramic plate, presser foot, and lead wire, and also fills the inside with an electrically insulating sealant.