JP3044088B2 - Pressure sensor and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor for detecting a pressure, such as a water pressure or a hydraulic pressure, as an electric signal and a method of manufacturing the same.

[0002]

2. Description of the Related Art As a pressure sensor for detecting a pressure such as a water pressure as an electric signal, a pressure sensor shown in FIG. 5 is conventionally known. The pressure sensor 11 has a small diameter portion 12a and a large diameter portion 1a.
2b, a pressure sensor element 13 having a pressure sensor chip 13b fixed to one side surface of a ceramic stem 13a and an amplifier in a small diameter portion 12a of the body 12. The diaphragm 15 is welded and fixed to the open end of the large diameter portion 12b. An oil chamber 16 is formed between the other side of the ceramic stem 13a and the diaphragm 15, and a pressure introduction hole 13c for guiding oil in the oil chamber 16 to the pressure sensor chip 13b is formed in the ceramic stem 1a.
The pressure is detected by the diaphragm 15 and transmitted to the pressure sensor chip 13b via oil.

Here, the formation of the oil chamber 16 and the injection of oil are performed in the steps shown in FIGS. First, a pressure sensor element 13 is prepared by fixing a pressure sensor chip 13b to one side surface of a ceramic stem 13a and performing wire bonding (a). Large diameter part 1
A body 12 having a diaphragm 15 welded to the opening end of 2b is prepared (b). Then, the pressure sensor element 13 is accommodated in the small diameter portion 12a of the body 12, and the outer periphery of the ceramic stem 13a is sealed by a rubber packing 17 mounted on the inner periphery of the small diameter portion 12a to form an oil chamber 16 (c). Subsequently, oil is injected into the oil chamber 16 from an oil injection port 13d provided with a check valve provided in the ceramic stem 13a (d).

[0004]

By the way, the conventional pressure sensor 11 has a structure in which the diaphragm
5 is fixed by welding, a margin for welding is required on the outer peripheral portion of the diaphragm 15, and the diameter of the diaphragm 15 tends to increase. This means that the oil volume increases along with the volume of the oil chamber 16, which causes the expansion and contraction amounts due to the temperature change of the oil to increase, and causes an error in the pressure detection of the pressure sensor to increase. In addition, a step of injecting oil into the oil chamber 16 after the oil chamber 16 is formed requires a separate step, resulting in poor productivity, and improvement is demanded.

Accordingly, an object of the present invention is to provide a pressure sensor capable of reducing a pressure detection error caused by a change in oil temperature in an oil chamber and improving productivity, and a method of manufacturing the same.

[0006]

In order to achieve this object, a pressure sensor according to the present invention has an oil chamber formed between a pressure sensor element having a pressure sensor chip and a diaphragm, and detects an oil pressure detected by the diaphragm. A pressure sensor for transmitting pressure to a pressure sensor chip via oil in a room, comprising a metal ring forming an oil chamber between the pressure sensor element and the diaphragm, and one end of the metal ring having the outer periphery of the diaphragm. And the other end is fitted and fixed to the outer periphery of the pressure sensor element via an adhesive to reduce the volume of the oil chamber.

In a method of manufacturing a pressure sensor according to the present invention, an oil chamber is formed between a pressure sensor element having a pressure sensor chip and a diaphragm, and a pressure detected by the diaphragm is applied to the pressure sensor via oil in the oil chamber. A method of manufacturing a pressure sensor of the type transmitting to a chip, wherein one end of a metal ring is curled to the outer periphery of the diaphragm, and the other end of the metal ring is bonded to the outer periphery of the pressure sensor element in oil via an adhesive. An oil chamber filled with oil is formed between the diaphragm and the pressure sensor element by fitting and fixing.

[0008]

According to the pressure sensor according to the present invention, since the outer periphery of the diaphragm is liquid-tightly curled to one end of the metal ring, no welding margin is required on the outer periphery of the diaphragm. Become. For this reason, the diameter of the diaphragm is reduced and the volume of the oil chamber is reduced, and the pressure detection error of the pressure sensor due to the change in the oil temperature in the oil chamber is reduced.

Further, the step of forming the oil chamber by fitting and fixing the other end of the metal ring to the outer periphery of the ceramic plate in a liquid-tight manner is performed in the oil, so that the oil automatically enters the oil chamber. Is filled without excess or shortage. Therefore, a separate step of filling the oil chamber with the oil is not required, and the productivity is improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention shown in the drawings will be described below. In FIG. 1 showing a sectional view of the pressure sensor 1,
Reference numeral 2 denotes a body using a hexagon nut having a mounting hole 2a. Inside the body 2, a pressure sensor element 5 having a stainless steel diaphragm 4 fixed via a metal ring 3, and a pressure sensor element 5 And an amplifier 6 for amplifying the detection signal of the above.

As shown in FIG. 2, the pressure sensor element 5 has two lead pins 5c connected to the amplifier 6 on one side surface of a disc-shaped ceramic stem 5b having a pressure introduction hole 5a formed in the center. A pin board 5d and a silicon pressure sensor chip 5e are bonded and fixed, and the silicon pressure sensor chip 5e is disposed at the center of the ceramic stem 5b so as to close the pressure introducing hole 5a. The electrodes of the silicon pressure sensor chip 5e are connected to the electrodes of the pin board 5d by wire bonding.

The outer periphery of the diaphragm 4 is joined to one end of the metal ring 3 in a liquid-tight manner by curling. The other end of the metal ring 3 is fitted to the outer periphery of the ceramic stem 5b of the pressure sensor element 5, and is bonded in a liquid-tight manner via a silicone rubber-based adhesive, so that the diaphragm 4 and the ceramic stem 5 5b, an oil chamber 7 having a smaller volume than before and in which oil is sealed is formed (see FIG. 3).

As shown in FIG. 1, a retaining ring 8 is attached to the inner periphery of the body 2, and the other end of the metal ring 3 fitted to the outer periphery of the ceramic stem 5b by the retaining ring 8. The caulking is fixed. The amplifier 6 connected to the lead pin 5c of the pressure sensor element 5 is prevented from falling off by a cover cap 9 fitted on the inner periphery of the body 2.

FIGS. 4A to 4E show the pressure sensor 1.
First, a circular ceramic stem 5b having an oil hole 5a formed in the center is prepared (a). Then, on one surface side of the ceramic stem 5b, a silicon pressure sensor chip 5e is adhesively fixed to a central portion so as to cover the pressure introducing hole 5a, and a pin board 5d having a lead pin 5c is adhesively fixed to a peripheral portion,
The electrode of the silicon pressure sensor chip 5e is connected to the electrode of the pin board 5d by a wire bonder, and the pressure sensor element 5
(B). Subsequently, a silicone rubber-based adhesive is applied to the outer periphery of the ceramic stem 5b of the pressure sensor element 5 (c). Further, a metal ring 3 having an enlarged diameter portion 3a for curling formed at one end and a diaphragm 4 fitted to the enlarged diameter portion 3a and having an outer peripheral portion curled are prepared, and a winding machine or the like is used. Then, both are subjected to a curling process and both are joined in a liquid-tight manner (d).

After such preparation, the oil chamber 7 is formed by fitting the other end of the metal ring 3 to the outer periphery of the ceramic stem 5b to which the adhesive is applied in a liquid-tight manner. The process is performed in oil to be sealed in the oil chamber 7 (e).

The pressure sensor 1 manufactured as described above
When the diaphragm 4 is elastically displaced by, for example, water pressure, the oil in the oil chamber 7 transmits the water pressure to the silicon pressure sensor chip 5e via the pressure introduction hole 5a. Then, the silicon pressure sensor chip 5e generates a voltage corresponding to the water pressure, and the amplifier 6 amplifies the voltage, whereby the pressure sensor 1 converts the water pressure into an electric signal and detects it.

Here, the pressure sensor 1 includes a diaphragm 4
Is welded to one end of the metal ring 3 in a liquid-tight manner, so that it is not necessary to provide a welding margin on the outer periphery of the diaphragm 4 unlike the conventional case, and the diaphragm 4 has a smaller diameter. Therefore, the volume of the oil chamber 7 is reduced as compared with the conventional case, and the oil volume is reduced, so that the pressure sensor 1 is less affected by the change in the oil volume due to the temperature change, and the detection error is reduced.

In the manufacturing process of the pressure sensor 1,
The step of forming the oil chamber 7 by fitting the other end of the metal ring 3 to the outer periphery of the ceramic stem 5b in a liquid-tight manner is performed in oil. Filling without excess or shortage. Therefore, the oil chamber 7
A separate step of filling the oil inside is not required.

[0019]

As described above, according to the present invention,
Since the outer periphery of the diaphragm is liquid-tightly curled to one end of the metal ring, there is no need to provide a welding margin on the outer periphery of the diaphragm as in the conventional case. For this reason, the diameter of the diaphragm is reduced and the volume of the oil chamber is reduced, so that a pressure detection error of the pressure sensor due to a change in the oil temperature in the oil chamber can be reduced.

Further, the step of forming the oil chamber by fitting and fixing the other end of the metal ring to the outer periphery of the ceramic plate in a liquid-tight manner is performed in the oil, so that the oil automatically enters the oil chamber. Is filled without excess or shortage. Therefore, a separate step of filling the oil chamber with oil is not required, and productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a pressure sensor according to the present invention.

FIG. 2 is a side view of a pressure sensor element according to one embodiment.

FIG. 3 is a sectional view of an oil chamber in one embodiment.

FIGS. 4 (a) to 4 (e) are views showing manufacturing steps of one embodiment, respectively.

FIG. 5 is a sectional view showing a conventional example of a pressure sensor.

FIGS. 6 (a) to 6 (d) are diagrams showing manufacturing steps of a conventional example, respectively.

[Explanation of symbols]

 1, 11 pressure sensor 2, 12 body 2a mounting hole 3 metal ring 3a enlarged diameter part 4, 15 diaphragm 5, 13 pressure sensor element 5a, 13c pressure introduction Hole 5b Ceramic stem 5c Lead pin 5d Pin board 5e Silicon pressure sensor chip 6, 14 Amplifier 7, 16 Oil chamber 8 Retaining ring 9 Cover cap 12a Small diameter Part 12b Large diameter part 13a Ceramic stem 13b Pressure sensor chip 13d Oil inlet 17 Rubber packing

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01L 19/00 G01L 9/04-9/04 101

Claims (2)

(57) [Claims] An oil chamber (7) is formed between a pressure sensor element (5) having a pressure sensor chip (5e) and a diaphragm (4), and a pressure detected by the diaphragm (4) is applied to the oil chamber (7). A pressure sensor (1) of the type transmitting to the pressure sensor chip (5e) via the oil in (), wherein an oil chamber (7) is formed between the pressure sensor element (5) and the diaphragm (4). A metal ring (3), which has one end portion curled to the outer periphery of the diaphragm (4) and the other end fitted and fixed to the outer periphery of the pressure sensor element (5) via an adhesive. A pressure sensor having a reduced volume of the oil chamber (7). 2. An oil chamber (7) is formed between a pressure sensor element (5) having a pressure sensor chip (5e) and a diaphragm (4), and a pressure detected by the diaphragm (4) is applied to the oil chamber (7). A method of manufacturing a pressure sensor (1) in which oil is transmitted to a pressure sensor chip (5e) via oil in (1), wherein one end of a metal ring (3) is curled to the outer periphery of the diaphragm (4). Then, the other end of the metal ring (3) is fitted and fixed to the outer periphery of the pressure sensor element (5) via an adhesive in oil, and the oil is sealed between the diaphragm (4) and the pressure sensor element (5). A method for manufacturing a pressure sensor, comprising forming an oil chamber (7).