Sensor apparatus integrated to injector of internal combustion engine

A sensor apparatus that outputs an electrical signal responding to a physical quantity is provided. The sensor apparatus includes: a housing being screwed to a body and having an insertion hole; an electrical circuit section having an electrical component used for processing the electrical signal, being disposed at an one end side of the housing and integrated with the housing; and a plurality of pins inserted through the electrical circuit section, a first end of the pin being inserted into the insertion hole to be fixed therewith, a second end of the pin being protruded from the electrical circuit section to be capable of engaging with a jig. The jig is used to screw the housing to the body after the housing and the electrical circuit are integrated with each other.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority from earlier Japanese Patent Application No. 2011-81943, filed on Apr. 1, 2011, the description of which is incorporated herein by reference.

BACKGROUND

1. Technical Field

The present application relates to sensor apparatuses, and more particularly to a sensor apparatus integrated to an injector of an internal combustion engine in which an electrical signal is outputted responding to a physical quantity of the injector.

2. Description of the Related Art

As an example of a sensor apparatus, Japanese Patent Application Laid-Open Publication No. 2010-242574 discloses a sensor apparatus which is integrated to an injector for injecting fuel to an internal combustion engine. The sensor apparatus detects the pressure of the fuel injected to the internal combustion engine and is designed such that an electrical circuit section such as a molded integrated circuit (IC) of the sensor apparatus is integrated to a housing that is screwed to the injector-body by using a jig capable of engaging with the outer peripheral portion of the housing. In particular, the jig passes over the electrical circuit section from one end side of the axial-direction of the housing to engage with the outer peripheral portion of the housing.

However, according to conventionally-used sensor apparatus, the outer shape of the housing is necessary to be larger than that of the electrical circuit section to enable the jig to be engaged with the outer peripheral portion of the housing. As a result, because of the above-described reason, the sensor apparatus cannot be shrunk in size easily.

SUMMARY

An embodiment provides a sensor apparatus capable of shrinking size thereof.

As a first aspect of an embodiment, a sensor apparatus that outputs an electrical signal responding to a physical quantity is provided. The sensor apparatus includes: a housing screwed to a body and having an insertion hole; an electrical circuit section having an electrical component used for processing the electrical signal, being disposed at an one end side of the housing and integrated with the housing; and a plurality of pins inserted through the electrical circuit section, each of the pin having a first end and a second end, the first end of the pin being inserted into the insertion hole to be fixed therewith, the second end of the pin being protruded from the electrical circuit section to be capable of engaging with a jig. The jig is used to screw the housing to the body after the housing and the electrical circuit are integrated with each other.

According to the first aspect, the pin fixed to the housing and the jig are engaged so that the jig can be used to screw the housing to the body. Therefore, since it is not necessary to design the outer shape of the housing to become larger than the electrical circuit section, the sensor apparatus can be shrunk.

According to a second aspect of an embodiment, a sensor apparatus that outputs an electrical signal responding to a physical quantity is provided. The sensor apparatus includes a body; a housing being screwed to the body; an electrical circuit section having an electrical component used for processing the electrical signal, being disposed at an one end side of the housing and integrated with the housing; and a plurality of pin portion included in a jig. The electrical circuit section includes a through hole that enables the pin portion to be inserted therethrough. The housing includes an insertion hole capable of engaging to the tip of the pin portion. The jig is used to screw the housing to the body after the housing and the electrical circuit are integrated with each other.

According to the second aspect, the pin portion of the jig is engaged to the pin-insertion hole of the housing and the housing is screwed to the body by the jig. Hence, since it is not necessary to design the outer shape of the housing to become larger than the electrical circuit section, the sensor apparatus can be shrunk.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the drawings, hereinafter will be described embodiments according to the present application. It is noted that portions which are mutually identical or similar in the embodiments are labeled with the same reference numbers.

First Embodiment

With reference toFIGS. 1 to 6, it is described the first embodiment according to the present application.FIG. 1is a front-cross-sectional view showing a major portion of an injector including a sensor apparatus,FIG. 2is a plan view showing the injector before a first terminal member is assembled,FIG. 3is a plan view showing the injector after the first terminal member is assembled,FIG. 4Ais a front-cross-sectional view showing a major portion of the sensor apparatus in the injector illustrated inFIG. 1,FIG. 4Bis a plan view showing the major portion of the sensor apparatus according toFIG. 4A,FIG. 5Ais a plan view showing the terminal member itself of the terminal member illustrated inFIG. 1,FIG. 5Bis a cross sectional view taken from a line A-A ofFIG. 5A, andFIG. 6is a front-cross-sectional view showing the major portion of the sensor apparatus ofFIG. 1and a jig used for assembling.

As shown inFIGS. 1 and 4, the injector is used to inject high pressure fuel supplied by a common-rail injection system (not shown) into the cylinders of the diesel engine. In an injector body10(i.e., a body) made of metal as an attached body where the injector is attached, a high pressure passage100through which the high pressure fuel flows and a bypass passage101which is bypassed from the high pressure passage100are formed.

A metal housing12having flanged cylindrical shape is screwed to the upper end of the injector body10. The housing12includes a male screw portion120, a thin wall portion121and three pin-insertion holes122. The male screw portion120is used to screw the housing12into the injector body10. The thin wall portion121is capable of being transformed in response to a pressure of the fuel being led via the bypass passage101. A pin40(described later) is inserted into the pin-insertion hole122(i.e., insertion hole).

The thin wall portion121includes a sensor section14being attached thereto. The resistor value of the sensor section14varies depending on a rate of the transformation of the thin wall portion121(i.e., in response to the fuel-pressure of the fuel at the high pressure passage100).

At one end side of the axial-direction X of the housing12, a molded IC (integrated circuit)16as an electrical circuit section is disposed to surround the thin wall portion121and the sensor section14. The molded IC16includes a signal processing IC160as an electrical component and a lead frame161which is connected to the signal processing IC160. The signal processing IC160outputs an electrical signal responding to the fuel-pressure, based on a variation of the resistor value of the sensor section14.

The signal processing IC160and the lead frame161are encapsulated by a mold-resin layer162having an excellent electrical-insulation property. A sensor terminal163included in the lead frame161protrudes from a side surface of the outer periphery of the mold-resin layer162. Three IC through holes164(i.e., through hole) where the pin40is inserted therethrough are formed on the lead frame161and the mold-resin layer162.

A shield cover18made of metal plate in order to shield electrical noise is disposed at an anti-housing side (upward direction inFIG. 1andFIG. 4A) of the mold IC16. The shield cover18includes three cover through holes180to which the pins40are inserted.

The pin40is formed by a metal to have a cylindrical shape. The pin40includes a flange section400formed at a middle portion in the axial direction thereof. The pin40is inserted into the cover through hole180and the IC through hole164and one end (i.e., first end) of the pin40is fixed into a hole122by press-fitting. As a result, the molded IC16and the shield cover18are sandwiched between the flange section400of the pin40and the housing12so that the housing12, the molded IC17and the shield cover18are integrated. The other end (i.e., second end) of the pin40and the flange section400are protruded from the molded IC16and the shield cover18.

A relay-terminal member20having a plurality of relay-terminal200is disposed at an anti-housing side of the shield cover18. The shield cover18and the relay-terminal member20are joined by an adhesive.

A first terminal member22having a plurality of first terminals is disposed at an anti-housing side of the relay-terminal member20. A second terminal member24having a plurality of second terminals is disposed at an anti-housing side of the first terminal member22. Further, an insulation member26having approximately cylindrical shape is disposed at an anti-housing side of the second terminal member24. The insulation member26is made of resin having an excellent electrical-insulation property. A plurality of lead wire28is penetrated through a through hole260of the insulating member26. A waterproof member29seals a portion between the through hole260and the lead wire28. The waterproof member29is formed by a rubber to have cylindrical shape.

A cover30having cylindrical shape is screwed to one end of the injector body10and a disk-shape cap32is fixed to the opening end of the cover30by press-fitting. In a space surrounding by the injector body10, the cover30and the cap32, the housing12and the molded IC16and the like are accommodated.

As shown inFIG. 4B, outer shapes of the housing12, the molded IC16and the shield cover18when viewing towards the axial-direction X of the housing12are similar figures. The outer shape of the housing12is smaller than that of the molded IC16and the shield cover18when viewing towards the axial-direction X of the housing12.

As shown inFIG. 1andFIG. 2, the relay-terminal member20includes a mold-resin layer202made of mold-resin in which four relay-terminals200made of conductive metal are integrated by molding to have disk shape. One end section of the four relay-terminals200is protruded from the outer periphery side of the mold-resin layer202, and the one end section is welded to the sensor terminal163of the molded IC16.

Three relay-terminals200among the four relay-terminals200include a portion having an arc shape (i.e., arc-shape portion) disposed concentrically about the axial-direction X. The middle portion is exposed to one end side of the mold-resin layer202. One relay-terminal200among the four relay-terminals200includes a portion having approximately rectangular shape (i.e., rectangular-shape portion) that is exposed to the one end side of the mold-resin layer202.

As shown inFIG. 3andFIG. 5, the first terminal member22includes a mold-resin layer220made of resin in which four first terminals221made of conductive metal are integrated by molding. The mold-resin layer220has a disk shape and an opening portion222having a rectangular shape formed at central portion of the mold-resin layer220.

The four first terminals221are press-formed from a plate having thin-thickness and narrow-width to have rectangular (strip) shape. The four first terminals221are disposed in parallel each other. In the first terminal221, a portion locating at a middle portion in a longitudinal direction thereof is in the opening portion222. Further, in the middle portion of the first terminal221, a convex portion223protruded to the arc-shape portion and the rectangular portion of the relay-terminal200is formed. The convex portion223is welded with the arc-shape portion and the rectangular-shape portion of the relay-terminal200.

The first terminal221has two end portions in the longitudinal direction thereof in which either one end portion is protruded from the mold-resin layer220. The end portion224protruded towards longitudinal direction is hereinafter referred to a protrusion224.

As shown inFIG. 1, the second terminal member24includes a mold-resin layer240made of resin in which four second terminals241made of conductive metal are integrated by molding.

The second terminal241has L-shape and both ends are protruded from the mold-resin layer240. One end side of the second terminal241is welded with the protrusion224of the first terminal221and the other end side of the second terminal241is electrically connected to the lead wire28.

The signal processing IC160is electrically connected to a plurality of lead wires28via the sensor terminal163, the relay-terminal member20, the first terminal member22and the second terminal member24. These lead wires28are used for connection of a power supply to the signal processing IC160, ground connection, signal wire through which sensor signal is transmitted to an engine-ECU from the sensor section.

Next, an assembling procedure for attaching the housing12and the molded IC16to the injector body10is described as follows.

First, a sensor sub-assembly is prepared. Specifically, the sensor section14is attached to the thin wall portion121of the housing12. Next, after applying adhesive to a surface of the molded IC16(surface facing to the housing12), positions of the pin-insertion hole122and the IC through hole164are adjusted to be located at the same axis whereby the housing12and the molded IC16are integrated.

Subsequently, the sensor section14and the signal processing IC160of the molded IC16are electrically connected by bonding wires. Then, after an adhesive is applied to a surface of the shield cover18(a surface facing to the molded IC16), positions of the IC through hole164and the cover through hole180are adjusted to be located at the same axis whereby the shield cover18is integrated with the housing12and the molded IC16.

The pin40is inserted into the cover through hole180and the IC through hole164, and one end of pin40is fixed into the pin-insertion hole122by press-fitting. As a result, assembling the sensor sub-assembly is completed.

Further, a lead wire sub-assembly is prepared. Specifically, the second terminal member24and the lead wire28are integrated and the cap32and the insulating member26are integrated. Then, the lead wire28is put through the cover30and the through hole260of the insulating member26whereby the lead wire sub-assembly is assembled.

As shown inFIG. 6, the sensor sub-assembly is attached to the injector body10by using a jig50. The jig50includes three pin-engaging holes500. Each of the pin-engaging holes500is capable of engaging with the other end of the pin40which is protruded from the shield cover18. The other end of the pin40is inserted into the pin-engaging hole500so as to engage each other. Then, having the jig50rotate about the axial-direction X, the male screw portion120is screwed with the injector body10thereby attaching the sensor sub-assembly to the injector body10.

Next, the jig50is detached. As shown inFIG. 1, an adhesive is applied to a surface which is anti-molded IC16side of the shield cover18so as to bond the relay-terminal member20on the shield cover18. Then, the relay-terminal200of the relay-terminal member20and the sensor terminal163are welded.

The first terminal member22is placed on the relay-terminal member20and the relay-terminal200and the convex portion of the first terminal221are welded. Moreover, the second terminal member24of the lead wire sub-assembly is placed on the first terminal member221and the first terminal221and the second terminal241are welded.

Next, the sensor sub-assembly, the relay-terminal member20, the first terminal member22and the lead wire sub-assembly are molded by a resin as a secondary molding while they are attached to the injector body10. Subsequently, the cover30is screwed to the injector body10so as to attach the cover30to the injector body10.

The cover30is fixed to the insulating member26by press-fitting and the cap32and the insulating member26are attached to the cover30. Further, the waterproof member29is inserted to the through hole260of the insulating member26. As a result, attaching the housing12and the molded IC16to the injector body10is completed.

According to the first embodiment, the pin40fixed to the housing12and the jig50are engaged whereby the housing12and the injector body10are screwed to the injector body10by the jig50. Therefore, unlike the sensor apparatus used conventionally, the outer shape of the housing12is not necessary be larger than that of the molded IC16and the shield cover18. Accordingly, since the outer shape of the housing12can be smaller than that of the molded IC16and the shield cover18, the sensor apparatus can be shrunk.

Moreover, since the pin40can be used for adjusting positions of the molded IC16and the shield cover18, positions of the molded IC16and the shield cover18against the housing12can be adjusted more accurately.

Second Embodiment

Hereinafter will be described a second embodiment of the present application.FIG. 7is a front-cross-sectional view showing the major portion of the sensor apparatus according to the second embodiment of the present application and a jig used for assembling. In the second embodiment, only portions differing from the first embodiment is described as follows.

As shown inFIG. 7, three pin portions501having cylindrical shapes are formed in the jig50so that the pin40according to the first embodiment has been removed.

Next, a process of attaching the housing12and the molded IC16to the injector body10is described.

First, the sensor section14is attached to the thin wall portion121of the housing12. Subsequently, after applying adhesive to a surface of the molded IC16(surface facing to the housing12), positions of the pin-insertion hole122and the IC through hole164are adjusted to be located at the same axis whereby the housing12and the molded IC16are integrated.

Then, the sensor section14and the signal processing IC160of the molded IC16are electrically connected by bonding wires. Then, after an adhesive is applied to a surface of the shield cover18(a surface facing to the molded IC16), positions of the IC through hole164and the cover through hole180are adjusted to be located at the same axis whereby the shield cover18are integrated with the housing12and the molded IC16.

Subsequently, the pin portion501of the jig50is inserted to the cover through hole180and the IC through hole164. It is noted that the IC through hole164is designed to enable the pin portion501to be inserted therethrough. After the tip of the pin portion501is engaging to the pin-insertion hole122, having the jig50rotate about the axial-direction X, the male screw portion120of the housing12is screwed to the injector body10. Then, the jig50is detached from the cover through hole180and an assembling procedure similar to the first embodiment is performed.

According to the embodiment, the pin portion501of the jig50is engaged with the pin-engaging hole500of the housing12whereby the housing12is screwed to the injector body10by the jig50. As a result, since outer shape of the housing12can be smaller than that of the molded IC16and the shield cover18, the sensor apparatus can be shrunk as well.

Other Embodiment

According to the above-described embodiments, the present application is applied to injectors, however, the present application can be adapted to other apparatuses other than injectors.

Further, according to the above-described embodiments, a sensor apparatus that detects a pressure is described. However, the present application can be adapted to a sensor apparatus that detects physical quantities other than the pressure.