JPH08338780A - Manufacture of terminal for pressure sensor - Google Patents

Abstract

PURPOSE: To provide a manufacturing method of terminal for pressure sensor, whose waterproofness is excellent and which can be manufactured at a low cost. CONSTITUTION: The end part 11 on one side at a terminal 1 is inserted into a coupling hole 17 at a guide pin 2, a protruding part 16 at the guide pin 2 is inserted into a hole 8 for pin insertion at the terminal 1, and the terminal 1 is fixed temporarily to the guide pin 2. The terminal 1 is used as an insert, and a resin is injected and filled from a gate into an internal space which is partitioned and formed by the guide pin 2, an upper mold 3 and a lower mold 4. Thereby, a coupling member such as a slide pin or the like which couples the terminal 1 is not required, and the waterproof treatment of a hole trace after the coupling member has been pulled out, which has been required in conventional cases, is not required.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a pressure sensor terminal.

[0002]

2. Description of the Related Art Conventionally, as a method of manufacturing a terminal for taking out an electric signal of a pressure sensor, a method of fixing the terminal by insert molding during resin molding is known. For example, FIG. 9 shows a part of the step of fixing the terminal at the time of resin molding. This is a flat terminal 1 in the internal space formed by the upper mold and the lower mold of the molding die.
A guide pin 73 for holding is inserted, and both sides of the plate-shaped terminal 1 are sandwiched and fixed by slide pins 71 and 72, and a resin is injected and filled into the inner space of the outer peripheral portion of the terminal 1. After this resin injection and filling, slide pin 7
1 and 72 are pulled out, and the upper die 75, the lower die 76 and the guide pin 73 are removed. Then, a resin molded product obtained by insert molding the terminal 1 is completed. A hollow portion is formed in the pin hole 77 after the slide pins 71 and 72 of this molded product are removed. As shown in FIGS. 11 and 12, the hollow portion of the pin hole 77 is sealed with a potting portion 78 formed by resin potting for waterproofing.

[0003]

However, according to such a conventional terminal fixing method by resin molding, a slide pin mark remains after molding. This slide pin mark becomes a water entry path, and there is a risk of water entry. For this waterproofing, it has conventionally been necessary to seal the slide pin mark by resin potting or the like. Since potting requires many steps such as filling, defoaming, and high temperature curing,
It causes cost increase.

There is also a method of pulling out the slide pin before the molding resin is cured, and performing pull-out pin molding without leaving a pin hole mark. However, when performing this pull-out pin molding, in order to completely seal the pin hole mark, Molding conditions such as pin withdrawal timing, molding pressure, and resin temperature must be controlled with high accuracy, which is not suitable for mass production. An object of the present invention is to provide a method for manufacturing a pressure sensor terminal, which is excellent in waterproofing and can manufacture the pressure sensor terminal at low cost.

[0005]

According to a first aspect of the present invention, there is provided a method for manufacturing a pressure sensor terminal, wherein one end of the terminal is inserted into a locking hole of a guide pin, and then the other end of the terminal is inserted. The step of temporarily fixing the terminal to the guide pin by inserting the convex portion of the guide pin into the pin insertion hole formed on the side, and the guide pin temporarily fixing the terminal and the upper mold and the lower mold. And molding the resin by injecting and filling a resin into the internal space defined and formed by using the terminal as an insert.

In the method for manufacturing a pressure sensor terminal according to a second aspect of the present invention, in addition to the step according to the first aspect, the other end of the terminal is formed into the lower mold before resin injection and filling. It is characterized by locking. The molding die used in the method of manufacturing a pressure sensor terminal according to claim 3 of the present invention is characterized in that a gate position is provided at a position for preventing floating of the terminal by resin pressure during resin molding.

A method of molding a pressure sensor according to a fourth aspect of the present invention is characterized in that a primary molded product molded by the molding die is secondarily molded as an insert product.

[0008]

According to the method of manufacturing a terminal for a pressure sensor according to claim 1 of the present invention, by inserting the terminal into the locking hole and the pin insertion hole of the guide pin, the terminal is temporarily fixed to the guide pin. After fixing, the terminal is insert-molded with resin, so that a locking member such as a slide pin for locking the terminal becomes unnecessary. Therefore, the waterproof treatment of the hole traces after removing the locking member, which is conventionally required, becomes unnecessary.

According to the method of manufacturing a pressure sensor terminal according to the second aspect of the present invention, the other end of the terminal is locked to the lower mold before the resin is injected and filled.
Positioning of the terminal is ensured and floating is prevented. According to the molding die used in the method for manufacturing the pressure sensor terminal of the third aspect of the present invention, the terminal is prevented from floating by the resin pressure injected from the gate position during resin molding.

According to the pressure sensor molding method of the fourth aspect of the present invention, the waterproofing effect of the terminal is improved by secondary molding the primary molding molded by the molding die as an insert.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) An embodiment in which the present invention is applied to a method of forming a terminal portion of a pressure sensor by resin molding will be described. FIG. 1 shows a sectional view of a molding die for resin-molding the terminal 1 as an insert. In FIG. 1, 1 is a terminal, 2 is a guide pin, 3 is an upper die, 4
Indicates a lower mold, and 5 indicates a filling resin.

The shape of the terminal is shown in FIGS. 2 and 3, and the shape of the guide pin is shown in FIGS. 4 and 5. As shown in FIGS. 2 and 3, the terminal 1 is a three-pole terminal 1 in this case, which is formed by bending a flat metal plate into two L-shaped portions. In the terminal 1, a pin insertion hole 8 is formed between the first bent portion 9 and the second bent portion 10. One end 11 of the terminal 1 is an external extraction part, and the other end 12 is a sensor internal electrical connection contact part.

The guide pin 2 has the shape shown in FIGS. 4 and 5, and holds the terminal 1 when the terminal 1 is fixed by resin molding, and the terminal 1 is laterally arranged with respect to the upper die 3 and the lower die 4. Is a guide member for inserting. The guide pin 2 is formed by a main body 14, three round bar-shaped pin portions 15 protruding from the side surface of the main body 14, and a columnar shape having a diameter smaller than the outer diameter of the pin portion 15 at the tip of the pin portion 15. And a convex portion 16 that The protrusion 16 is a portion to be inserted into the pin insertion hole 8 of the terminal 1 during insert resin molding. A locking hole 17 for locking one end 11 of the terminal 1 is formed in the main body 14 as shown in FIG.

Next, a method of manufacturing the pressure sensor terminal will be described. First, one end 11 of the terminal 1 is inserted into the locking hole 17 of the guide pin 2, and the convex portion 16 of the guide pin 2 is inserted into the pin insertion hole 8. Then, the terminal 1 and the guide pin 2 are used as an upper mold 3 for molding.
And the other end 12 of the terminal 1 is locked in the locking groove 19 of the lower mold 4. Next, resin is injected from a gate (not shown) to fill the internal space with the molding resin. Then, as shown in FIG. 1, the filling resin 5 fills the internal space. Next, the guide pin 2 is pulled out, and the upper die 3 and the lower die 4 are pulled out. Then, the molded product 21 including the terminal 1 and the filling resin 5 is taken out from the inside.
This molded product 21 becomes a molded product of the sensor terminal.
This is a primary molded product. This primary molded product is further secondary-formed, and the pressure sensor 23 as shown in FIG. 6 is formed by resin molding.

According to the present embodiment, it is not necessary to remove the slide pin before the molding resin is cured, and it is not necessary to control the pin withdrawal timing, molding pressure, resin temperature and other molding conditions with high accuracy. Therefore, the cost can be reduced. The structure of the pressure sensor 25 of this secondary molded product will be described with reference to FIG. The pressure sensor 25 includes a diaphragm 33 in an internal space formed by the upper case 31 and the lower case 32.
As a result, the pressure chamber 34 and the pressure chamber 35 are partitioned and formed. At the time of manufacture, the upper case 31 is formed by resin insert molding using the above-described primary molded product 21 shown in FIG. 1 as an insert member. The lower case 32 is formed with a pressure inlet 37, a throttle valve 38, a notch 39, and a diaphragm receiver 40.

The diaphragm 33 is a resin mold plate 41.
Is formed in a disk shape in the center, and the magnet 42 is fixed to the center of the resin mold plate 41. A compression coil spring 43 is housed inside the pressure chamber 35, one end 43 a of the compression coil spring 43 contacts the lower case 32, and the other end 43 b contacts the resin mold plate 41.

The upper case 31 has a Hall IC 4 at the other end 12 of the terminal 1 fixed to the inner wall surface of the pressure chamber 34.
4 is electrically connected. This Hall IC44
It is composed of a hall element and a signal processing circuit, maintains electrical connection with the terminal 1 and is mechanically fixed to the upper case 31. The Hall IC 44 outputs an electrical ON / OFF signal corresponding to the proximity distance between the Hall IC 44 and the magnet 42. The output voltage characteristic is as shown in FIG.

As shown in FIG. 7, the operating characteristic of the pressure sensor 25 is a state in which the pressure introduced from the pressure inlet 37 acts on the pressure chamber 35 and the pressure of the pressure chamber 35 is atmospheric pressure. As shown in FIG. 6, the magnet 42 is in the uppermost position in FIG. 6, that is, in the state of approaching the Hall IC 44. In this state, the output state of the Hall IC 44 is 0V off state. When negative pressure acts on the pressure inlet 37 from this state, when the negative pressure falls below a certain value, the diaphragm 33 is lowered from the position shown in FIG. 6 against the compression coil spring 43, and the magnet 42 is moved from the Hall IC 44. Gradually move downward. Then, when the value of the negative pressure in the pressure chamber 35 reaches a predetermined value, the signal of the Hall IC 44 is switched to the ON state of 5V. This voltage signal of 5V is taken out from the terminal 1. Hall IC44 Terminal 1
The output voltage of 5 is 5V and the Hall IC 44 is in the ON state. However, when the pressure of the pressure chamber 35 gradually increases from this state, the magnet 42 moves again toward the Hall IC 44. And when approaching a predetermined distance, Hall IC44
The output voltage of 1 is switched from 5V to 0V again, and the output voltage of the terminal 1 becomes 0V.

According to this embodiment, the terminal 1 portion of the primary molded product 21 forming a part of the upper case 31 is pre-sealed by the resin primary molding so that the waterproof function becomes sufficient. That is, it is possible to reliably prevent water or the like from entering the inside of the pressure chamber 34 from the outside through the terminal 1. Therefore, the pressure sensor 25 is excellent in waterproofness. The primary molded product 2
1, the terminal 1 is fixed at two points by the locking hole 17 of the guide pin 2 and the convex portion 16, so that the terminal 1 is formed as an insert member and is formed by the upper mold 3 and the lower mold 4. The insert resin molding can be performed by injecting the resin while the terminal 1 is surely positioned at a predetermined position in the internal space and the terminal 1 is positioned. Therefore, the terminal 1 can be positioned at the same time by the action of the guide pin 2 without using a separate member such as a slide pin as in the conventional case. Therefore, simply removing the guide pin 2 simplifies a molded product for fixing the terminal 1. It can be manufactured by simple insert resin molding. Further, the sealing function is reliably maintained in the manufactured terminal 1 portion. Furthermore, since a holder for holding the terminal 1 is not required, water does not enter from the space formed when the guide pin 2 is pulled out. Therefore, by producing this primary molded product in advance, the portion of the terminal 1 is obtained as a primary molded product, and when this primary molded product is made as a secondary molded product, this primary molded product is inserted into the insert member. Therefore, there is an effect that water intrusion is surely prevented by the primary molding and the secondary molding.
Therefore, this embodiment has an effect that the waterproof function of the terminal portion of the pressure sensor is extremely excellent.

Next, FIG. 8 shows a modification of mounting the magnet mounted on the diaphragm 33. FIG. 8A shows an example of the magnet 42 attached to the resin mold plate 41 shown in FIG.
In this example, the magnet 42 is attached to the resin mold plate 41 in the attachment groove portion 45 with an adhesive. In this example,
The magnet 42 can be easily attached to the resin mold plate 41 by an adhesive means such as an adhesive.

FIG. 8B shows a resin mold plate 51 and a magnet 52.
This is an example in which is fixed by insert molding. Since the magnet 52 is insert-molded during resin molding of the resin mold plate 51, the magnet 52 can be attached and fixed at the same time as insert molding. Therefore, since the step of fixing the magnet with an adhesive or the like is omitted, the manufacturing process is simplified.

FIG. 8C shows an example in which the magnet is formed as the plastic magnet 62 and has the same shape as the shape of the mold plate. In this example, since the mold plate itself is formed of a plastic magnet, the operation of individually bonding the magnets to the mold plate is unnecessary. The plastic magnet 62 is fixed to the diaphragm 33. As described above, according to the above embodiment, when the terminal 1 is insert-molded, the guide pin supports the terminal without using the slide pin, so that no trace of the slide pin remains. Therefore, the potting operation is not necessary for the pin mark portion, and the slide pin pulling out operation is also unnecessary, so that the step of potting on the pin mark is omitted. Further, when the terminal is molded and fixed, the guide pin is provided with the insert molding means, which reduces the number of molding parts and facilitates molding.

Further, the obtained terminal resin molded product is used as a primary molded product for secondary molding of the primary molded product.
The effect of preventing water intrusion by primary molding and secondary molding is great. Furthermore, by performing the molding process in two stages, it is possible to inexpensively manufacture a terminal integrated molding having excellent waterproofness. (Comparative Example) Conventional comparative examples are shown in FIGS.

As shown in FIG. 9, during the molding of the primary molded product,
The terminal 1 is held by the slide pins 71 and 72 from both sides, and one end 11 of the terminal 1 is inserted into the locking hole 74 of the guide pin 73 and locked. In this state, the terminal 1 and the slide pin 73 are inserted into the internal space formed by the upper mold 75 and the lower mold 76, and resin is injected and filled around the terminal 1 from the gate. The state where this resin is injected and filled is the state shown in FIG. The guide pin 71 and the guide pin 72 are pulled out vertically from the state shown in FIG. Next, the guide pin 73, the upper mold 75 and the lower mold 76 are removed and the primary molded product is taken out. A pin hole 77 is formed between the slide pin 71 and the slide pin 72 as shown in FIG. Potting resin is injected into this pin hole 77 to form a potting portion 78. The step of the potting section 78 is required. There has been a risk that water will invade the potting portion from the past.

In the conventional example, a potting operation is required when fixing the primary molded product, that is, the terminal, and there is a possibility that water or the like may enter from the potting portion when the sensor is used.

[Brief description of drawings]

FIG. 1 is a sectional view showing the inside of a molding die according to a first embodiment of the present invention.

FIG. 2 is a side view of the terminal of the first embodiment.

3 is a view in the direction of arrow III shown in FIG. 2. FIG.

FIG. 4 is a side view of a guide pin used in the first embodiment.

5 is a view from the direction of the arrow V shown in FIG.

FIG. 6 is a sectional view of a pressure sensor obtained by secondary molding of the primary molded product used in the first embodiment.

7 is a characteristic diagram showing the relationship between the signal pressure and the output voltage of the pressure sensor shown in FIG.

FIG. 8 is a partial cross-sectional view showing a modified example of the method of attaching the magnet used for the pressure sensor.

FIG. 9 is a cross-sectional view showing the inside of a molding die of a conventional comparative example.

10 is a cross-sectional view taken along line XX shown in FIG.

FIG. 11 is a cross-sectional view of a primary molded product showing a state in which the slide pin mark after molding shown in FIG. 9 is potted.

12 is a sectional view taken along line XII-XII shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Terminal 2 Guide pin 3 Upper mold 4 Lower mold 5 Filling resin 8 Pin insertion hole 9 First bent part 10 Second bent part 11 One end 12 The other end 14 Main body 15 Pin part 16 Convex Part 17 Locking hole 19 Locking groove 21 Primary molded product 23 Secondary molded product 25 Pressure sensor 31 Upper case 32 Lower case 33 Diaphragm 37 Pressure inlet 41 Resin mold plate 42 Magnet 43 Compression coil spring 44 Hall IC

Claims (4)

[Claims] 1. Inserting one end of a terminal into a locking hole of a guide pin, and then inserting a convex portion of the guide pin into a pin insertion hole formed on the other end side of the terminal. Then, the step of temporarily fixing the terminal to the guide pin, and the resin molding by injecting and filling the resin into the internal space defined by the guide pin temporarily fixing the terminal, the upper mold and the lower mold by using the terminal as an insert A method of manufacturing a terminal for a pressure sensor, comprising: 2. The method for manufacturing a pressure sensor terminal according to claim 1, wherein the other end of the terminal is locked to the lower mold. 3. The molding die used in the method of manufacturing a terminal for a pressure sensor according to claim 1, wherein a gate position is provided at a position at which the terminal is prevented from floating by resin pressure during resin molding. 4. A method of molding a pressure sensor, characterized in that a primary molded product molded by the molding die is secondarily molded as an insert product.