JP2013036886A - Sensor and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor in which reliability of output from a detection element is enhanced.SOLUTION: A sensor 1 includes a Hall IC 10, a case 40, a terminal 20, a cover 30, and a housing 50. The case 40 has a bottom 41 and a cylindrical section 42 extending from an outer edge of the bottom in one direction. The Hall IC 10 is stored at the bottom side in the cylindrical section 42. One end of a terminal 20 molded in the cover 30 is connected to the Hall IC 10, and the other end thereof extends to the outside of the case 40. The cover 30 blocks an opening of the cylindrical section 42 present at the opposite to the bottom. The housing 50 molds the cylindrical section 42, the cover 30, and the terminal 20. Thus, when injection molding the housing 50, the cover 30 prevents resin forming the housing 50 from entering the cylindrical section 42.

Description

  The present invention relates to a sensor for detecting a physical quantity and a manufacturing method thereof.

Conventionally, sensors that detect physical quantities such as magnetic flux density or temperature are known.
In the sensor of Patent Document 1, a detection element (“sensing unit 10” in Patent Document 1) is resin-molded by a case (“Mold Resin 15” in Patent Document 1), and the case is a housing (“Connector Unit” in Patent Document 1). The resin is molded by the case portion 30 "). Both the case and the housing are made of thermoplastic resin and are formed by injection molding. For this reason, after the case is primary molded and then the case is inserted and the housing is secondarily molded, the case and the housing are welded by heat during the second molding. As a result, the sensor prevents water and the like from entering between the case and the housing.

JP 2004-198240 A

However, in the sensor of Patent Document 1, there is a concern that excessive pressure due to injection molding may act on the detection element when the case is primary molded. Further, when the housing is secondarily molded, there is a concern that an excessive pressure due to injection molding is transmitted through the case and acts on the detection element. For this reason, there exists a possibility that the reliability of the output of a detection element may fall.
The present invention has been made in view of the above problems, and an object thereof is to provide a sensor that increases the reliability of the output of a detection element.

According to the first aspect of the present invention, the sensor includes a detection element, a case, a terminal, a cover, and a housing.
The detection element detects a physical quantity. The case has a bottom portion and a cylindrical portion extending to one side from the outer edge of the bottom portion, and houses the detection element on the bottom side of the cylindrical portion. One end of the terminal is connected to the detection element, and the other end extends to the outside of the case. The cover molds the terminal and closes the opening on the side opposite to the bottom of the cylindrical portion. The housing molds the cylindrical portion, the cover, and the terminal.
Thereby, when the housing is injection-molded, the cover prevents the resin forming the housing from entering the inside of the cylindrical portion. For this reason, the pressure when the housing is injection-molded is prevented from acting on the detection element. Therefore, the reliability of the output of the detection element can be increased.
The detection element corresponds to various elements that detect a physical quantity, such as a Hall IC or magnetoresistive element that detects magnetic flux density, a thermistor that detects temperature, or an element that includes a movable body that detects acceleration or angular velocity. .

According to the invention of claim 2, the cylindrical portion of the case has a small diameter portion that accommodates the detection element on the bottom side, a large diameter portion that has an inner diameter larger than the inner diameter of the small diameter portion on the side opposite to the bottom portion of the small diameter portion, and There is a step provided between the small diameter portion and the large diameter portion. The cover is inserted inside the large-diameter portion, and the end surface on the bottom side comes into contact with the step.
Thereby, when the housing is injection-molded, the pressure of the resin forming the housing acts on the end surface opposite to the bottom of the cover. For this reason, the end surface on the bottom side of the cover is pressed by the step, and the end surface on the bottom side of the cover and the step come into liquid-tight contact. Therefore, it is possible to reliably suppress the resin forming the housing from entering the inside of the case.

According to the invention of claim 3, the case has a space between the cover and the detection element.
This prevents the pressure of the resin forming the cover from acting on the detection element when the cover is injection molded. Therefore, the reliability of the output of the detection element can be increased.

According to the invention of claim 4, the case has a space between the bottom and the detection element.
As a result, pressure is prevented from acting on the detection element from the bottom, and the reliability of the output of the detection element can be increased.

According to the invention which concerns on Claim 5, a case and a housing are formed from a thermoplastic resin. A housing inserts a cylinder part, a cover, and a terminal, and is formed by injection molding.
Thereby, when forming a housing, a case and a housing are welded by the heat of injection molding. Therefore, it is possible to prevent water or the like from entering the inside of the case.

According to the invention which concerns on Claim 6, a sensor is equipped with the electronic component attached to a terminal and molded by the cover.
Thereby, an electronic component is sealed with a cover. For this reason, it can suppress that water etc. penetrate | invade into an electronic component.
In addition, as an electronic component, various things, such as a capacitor | condenser, resistance, a coil, or IC, correspond.

According to the seventh aspect of the invention, the sensor manufacturing method includes the following steps.
In the primary molding process, a terminal is inserted and a cover is injection molded.
In the connection step, the detection element is connected to one end of the terminal.
In the insertion step after the primary molding step and the connection step, the detection element is inserted into the bottom side of the cylindrical portion of the case and the opening of the case is closed with a cover.
After the insertion process, in the secondary molding process, the cylindrical portion, the cover, and the terminal are inserted, and the housing is injection molded.
Thereby, in the primary molding process and the secondary molding process, the pressure at the time of injection molding is suppressed from acting on the detection element, so that the reliability of the output of the detection element can be increased.

It is sectional drawing of the sensor by 1st Embodiment of this invention. It is a perspective view which shows the manufacturing process of the sensor by 1st Embodiment of this invention. It is a perspective view which shows the manufacturing process of the sensor by 1st Embodiment of this invention. It is a perspective view which shows the manufacturing process of the sensor by 1st Embodiment of this invention. It is a perspective view which shows the manufacturing process of the sensor by 1st Embodiment of this invention. It is a perspective view which shows the manufacturing process of the sensor by 1st Embodiment of this invention. 1 is a perspective view of a sensor according to a first embodiment of the present invention. It is a flowchart which shows the manufacturing process of the sensor by 1st Embodiment of this invention. It is sectional drawing of the sensor by 2nd Embodiment of this invention. It is a flowchart which shows the manufacturing process of the sensor by 2nd Embodiment of this invention.

Hereinafter, a plurality of embodiments according to the present invention will be described with reference to the drawings.
(First embodiment)
A sensor according to a first embodiment of the present invention is shown in FIGS.
The sensor 1 of this embodiment is applied as a stroke sensor and is attached to a vehicle transmission (not shown). An engaging member included in a transmission (not shown) has a magnetic circuit. The sensor detects a magnetic field that changes as the engaging member moves. A signal output from the sensor is transmitted to an electronic control unit (ECU) of the vehicle. The ECU detects the position of the engaging member based on the signal.

As shown in FIG. 1, the sensor 1 includes a Hall IC 10 as a detection element, a terminal 20, a cover 30, a case 40, a housing 50, and the like.
As shown in FIGS. 1 and 4, the Hall IC 10 is connected to a Hall element (not shown) that detects a magnetic field by the Hall effect, an integrated circuit (IC) (not shown) that processes a signal output from the Hall element, and the integrated circuit. Three leads 11 and a mold resin 12 for molding them. The output voltage of the Hall IC 10 changes according to the change of the magnetic field.

As shown in FIGS. 1 and 2, the terminal 20 is formed of three conductors. One end of the terminal 20 is connected to the lead 11 of the Hall IC 10 by welding or the like, and the other end extends to the outside of the case 40.
As shown in FIGS. 1 and 3, the cover 30 is formed from a thermoplastic resin or a thermosetting resin, and the terminal 20 is molded. The cover 30 includes a contact portion 31 formed in a disk shape, an extending portion 32 extending from the contact portion 31 along the terminal 20 to the Hall IC side, and a side opposite to the Hall IC 10 from the contact portion 31 along the terminal 20. And a fixing portion 34 provided substantially perpendicular to the protection portion 33 and the contact portion 31.
One surface of the terminal 20 in the plate thickness direction is exposed from the extending portion 32. As shown in FIGS. 1 and 4, a capacitor 60 as an electronic component is attached to the exposed surface of the terminal 20. The capacitor 60 absorbs noise.

As shown in FIGS. 1 and 5, the case 40 is formed of a thermoplastic resin and includes a bottom portion 41 and a cylindrical portion 42 that extends from the outer edge of the bottom portion 41 to one side. The cylindrical part 42 has a small diameter part 43, a step 44 and a large diameter part 45 in this order from the bottom side.
The small diameter portion 43 is provided with a storage chamber 46 in which the Hall IC 10 is stored. The inner width of the accommodation chamber 46 and the plate thickness of the Hall IC 10 are substantially the same. A space 70 is provided between the Hall IC 10 and the bottom 41. A space 71 is also provided between the Hall IC 10 and the cover 30.
The large diameter portion 45 is provided on the opposite side of the bottom portion 41 of the small diameter portion 43 and has an inner diameter larger than that of the small diameter portion 43. On the outer wall in the radially outward direction of the large diameter portion 45, a protrusion 47 is formed continuously in the circumferential direction. The protrusion 47 melts during the injection molding of the housing 50 and comes into close contact with the housing 50.

The contact portion 31 of the cover 30 is inserted inside the large diameter portion 45 of the case 40. The protection part 33 and the fixing part 34 can contact the inner wall of the large diameter part 45 in the radial direction. The end surface on the Hall IC side of the contact portion 31 contacts the step 44 connecting the small diameter portion 43 and the large diameter portion 45. As a result, the case 40 is closed.
The large diameter portion 45 is provided with a hole 48 communicating in the radial direction. A claw 37 provided on the fixing portion 34 of the cover 30 is fitted into the hole 48.
The step 44 is provided with a convex portion 49 that protrudes to the opposite side of the bottom portion 41. A concave portion 35 provided on the end surface on the bottom side of the cover 30 is fitted into the convex portion 49. Thereby, since the cover 30 is positioned in the circumferential direction, erroneous assembly of the case 40 and the cover 30 is prevented.

As shown in FIGS. 1 and 6, the housing 50 is made of a thermoplastic resin and includes a housing main body 51, a flange portion 52, and a connector 53.
The housing main body 51 is molded with the large-diameter portion 45 of the cylindrical portion 42, the cover 30, and the terminal 20. As shown in FIGS. 1 and 7, an O-ring 55 is attached to a groove 54 formed on the outer periphery of the housing body 51.
The flange portion 52 extends outward from the housing body 51. The flange portion 52 is provided with an attachment hole 56, which can be attached to a transmission component (not shown).
The terminal 20 is exposed inside the connector 53. An external terminal (not shown) is fitted into the connector 53. A signal output from the Hall IC 10 is transmitted from the terminal 20 exposed at the connector 53 to the ECU of the vehicle.

A method for manufacturing the sensor 1 will be described with reference to the flowchart of FIG. 8 and FIGS.
In the first step S1 (hereinafter, “step” is omitted and simply indicated by the symbol “S”), the terminal 20 is inserted and the cover 30 is injection-molded as a primary molding process (see FIG. 3). Thereby, the three terminals 20 are fixed to each other.
Next, in S2, as a connecting step, the lead 11 of the Hall IC 10 and one end of the terminal 20 are fixed by welding.
Subsequently, in S3, as an electronic component connecting step, the capacitor 60 is connected to the terminal 20 by soldering (see FIG. 4).

  Subsequently, in S4, as an insertion process, the Hall IC 10 is inserted into the accommodation chamber 46 of the case 40 (see FIGS. 1 and 5). At the same time, the contact portion 31 of the cover 30 is inserted inside the large-diameter portion 45 of the case 40, and the step 44 of the case 40 is brought into contact with the end surface of the contact portion 31 on the Hall IC side. At this time, the convex portion 49 of the case 40 and the concave portion 35 of the cover 30 are fitted, and the claw 37 of the cover 30 is fitted into the hole 48 of the large diameter portion 45 of the case 40. As a result, the opening of the case 40 is closed by the cover 30.

Next, in S5, as a secondary molding step, the cylindrical portion 42, the cover 30 and the terminal 20 are inserted, and the housing 50 is injection molded (see FIGS. 1 and 6). At this time, the pressure of the resin forming the housing 50 acts on the end surface on the opposite side of the bottom 41 of the contact portion 31 of the cover 30. Thereby, the end surface on the bottom side of the contact portion 31 is pressed by the step 44. For this reason, since the end surface on the bottom side of the contact portion 31 and the step 44 are in liquid-tight contact, the resin forming the housing 50 is prevented from entering the inside of the case 40.
Thereafter, an O-ring 55 or the like is attached to the housing body 51 (see FIG. 7). After the performance inspection and the appearance inspection, the sensor 1 is completed.

In the present embodiment, the following effects are obtained.
(1) In this embodiment, after the cover 30 is injection-molded, the Hall IC 10 and the terminal 20 are connected. For this reason, the pressure of the resin forming the cover 30 is prevented from acting on the Hall IC 10 in the primary molding step. Therefore, the reliability of the output of the Hall IC 10 can be improved.
(2) In the present embodiment, the cover 30 prevents the resin forming the housing 50 from entering the inside of the cylindrical portion 42 in the secondary molding step. For this reason, it is possible to prevent the pressure of the resin forming the housing 50 from acting on the Hall IC 10.
(3) In the present embodiment, when the housing 50 is injection molded, the pressure of the resin acts on the contact portion 31 of the cover 30, and the contact portion 31 is pressed against the step 44 of the case 40. For this reason, since the contact part 31 and the level | step difference 44 contact | abut liquid-tightly, it can prevent reliably that resin which forms the housing 50 penetrate | invades inside the case 40. FIG.
(4) In the present embodiment, the case 40 has spaces 70 and 71 between the cover 30 and the Hall IC 10 and between the bottom 41 and the Hall IC 10. Thereby, pressure is prevented from acting on the Hall IC 10 in the insertion step and the secondary molding step, so that the reliability of the output of the detection element can be increased.
(5) In the present embodiment, the protrusion 47 provided on the outer wall of the case 40 melts during the injection molding of the housing 50 and closely contacts the housing 50. Therefore, it is possible to prevent water or the like from entering the inside of the case 40.
(6) In the present embodiment, the terminal 20 is molded by the extending portion 32 of the cover 30. Thereby, since the position of the three terminals 20 is fixed, the capacitor | condenser 60 can be attached easily.

(Second Embodiment)
A sensor according to a second embodiment of the present invention is shown in FIGS. In the second embodiment, components substantially the same as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.
In the second embodiment, the capacitor 60 is molded in the extending portion 32 of the cover 30. The terminal 20 is exposed only from the extending portion 32 to the Hall IC side.
The manufacturing method of the sensor of the second embodiment is shown in the flowchart of FIG.
First, as an electronic component connecting step, the capacitor 60 is connected to the terminal 20 (S3).
Next, as a primary molding step, the terminal 20 and the capacitor 60 are inserted, and the cover 30 is injection molded (S1).
Subsequent manufacturing steps S2, S4 and S5 are the same as those in the first embodiment.
In the second embodiment, since the capacitor 60 is sealed by the cover 30, it is possible to prevent water or the like from entering the capacitor 60.

(Other embodiments)
In the above-described embodiments, the present invention is applied to the stroke sensor. On the other hand, the present invention can be applied as a sensor for detecting various physical quantities such as temperature, acceleration or angular velocity. In this case, the detection element can be, for example, a thermistor in the case of a temperature sensor, a magnetoresistive element in the case of a magnetic sensor, or an element having a movable body that is displaced according to acceleration or angular velocity in the case of an acceleration or angular velocity sensor. is there.
Thus, the present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 1 ... Sensor 10 ... Hall IC (detection element)
20 ... Terminal 30 ... Cover 40 ... Case 41 ... Bottom 42 ... Tube 43 ... Small diameter 44 ... Step 45 ... Large diameter 50 ... Housing

Claims (7)

A detection element for detecting a physical quantity;
A case having a bottom portion and a cylindrical portion extending to one side from an outer edge of the bottom portion, and housing the detection element on the bottom side of the cylindrical portion;
A terminal having one end connected to the detection element and the other end extending outside the case;
A mold that molds the terminal and closes an opening on the opposite side of the bottom of the cylindrical portion;
And a housing for molding the cylindrical portion, the cover, and the terminal. The cylindrical portion of the case includes a small-diameter portion that accommodates the detection element on the bottom side, a large-diameter portion that has an inner diameter larger than the inner diameter of the small-diameter portion on the opposite side of the small-diameter portion, and the small-diameter portion And a step provided between the large diameter portion and
The sensor according to claim 1, wherein the cover is inserted inside the large-diameter portion, and an end surface on the bottom portion side abuts on the step.   The sensor according to claim 1, wherein the case has a space between the cover and the detection element.   The sensor according to claim 1, wherein the case has a space between the bottom and the detection element. The case and the housing are formed of a thermoplastic resin,
The sensor according to any one of claims 1 to 4, wherein the housing is formed by injection molding by inserting the cylindrical portion, the cover, and the terminal.   The sensor according to any one of claims 1 to 5, further comprising an electronic component attached to the terminal and molded on the cover. It is a manufacturing method of the sensor according to any one of claims 1 to 6,
A primary molding step of inserting the terminal and injection molding the cover;
Connecting the detection element to one end of the terminal;
After the primary molding step and the connection step, the insertion step of inserting the detection element on the bottom side of the cylindrical portion of the case, and closing the opening of the case with a cover,
After the insertion step, a secondary molding step of inserting the cylindrical portion, the cover, and the terminal and injection molding the housing is included.

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