JP2002035850A - Sealing method for oil-filling pipe of liquid-seal type pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an overflow of oil from an oil-filling pipe that occurs while a sealing process is going on, and also to prevent the sealing by welding and the like to become defective due to overflowed oil. SOLUTION: A temporary sealing part 50 is formed by crushing and clamping down a tip-neighborhood part 19a of the oil-filling pipe 19 to a streak shape across the pipe, a tip-side part at the rear of the temporary sealing part 50 is crushed to flat and a part to be sealed of the flat-crushed edge face 52 of the tip of the pipe is sealed by welding or soldering.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sealing an oil filling pipe of a liquid ring type pressure sensor, and more particularly to a method for sealing a tip of an oil filling pipe in a liquid-tight manner.

[0002]

2. Description of the Related Art As a pressure sensor for detecting a fluid pressure, an incompressible fluid such as oil (sensor protection oil) is placed in a sealed chamber (liquid sealing chamber) separated from a fluid area to be measured by a diaphragm.
And a pressure detecting element such as a piezoresistive pressure sensor is fixedly arranged, and the fluid pressure of the measured fluid area acting on the diaphragm is applied to the pressure detecting element via the incompressible fluid in the liquid sealing chamber. 2. Description of the Related Art There is known a liquid-sealed pressure sensor that detects a fluid pressure in a fluid area to be measured by a pressure detection element. This type of pressure sensor is disclosed, for example, in Japanese Patent Publication No. 6-65974.

[0003] In the above-mentioned liquid ring type pressure sensor, an oil filling pipe is provided to fill the liquid ring chamber of the liquid ring type pressure sensor with oil. Permanent sealing of the tip is performed. The sealing of the oil filling pipe must be performed reliably and reliably so as to completely seal the liquid sealing chamber and prevent oil leakage for a long period of time.

[0004] Conventionally, sealing of an oil filling pipe is performed by closing the pipe with welding or soldering.

[0005]

There are two problems in sealing a conventional oil filling pipe. One of them is to prevent the oil from flowing out from the unfilled oil filling pipe during the sealing process by welding or soldering, and to ensure the soundness of the oil filling volume in the liquid sealing chamber. Is not taken into account. For this reason, during the sealing step by welding or solder, oil may flow out of the unfilled oil filling pipe, and the amount of oil filled in the liquid sealing chamber may be reduced.

Another problem in the conventional sealing of an oil filling pipe is that in the sealing step by welding or soldering, the oil in the oil filling pipe is heated and vaporized by welding heat or the like, so that the oil filling pipe is heated. Sealing by welding or the like is not reliably performed due to oil that blows out from the pipe.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. During the sealing step, oil does not flow out of an unsealed oil filling pipe, and the oil does not blow out. The oil sealing of the liquid ring type pressure sensor with high reliability and reliability without oil incomplete sealing by welding, etc., without oil leakage over a long period of time. It aims at a method of sealing a filling pipe.

[0008]

In order to achieve the above object, a method for sealing an oil filling pipe of a liquid ring type pressure sensor according to the present invention is provided by a liquid ring type pressure sensor. In a method of sealing an oil filling pipe for filling oil into a chamber, a temporary sealing portion is provided by crushing a portion near the tip of the oil filling pipe in a streak shape in a cross direction of the pipe, and temporarily sealing the oil. The flat end of the pipe is crushed flat, and the sealed portion of the flat crushed end face of the pipe is welded or sealed with solder.

According to a second aspect of the present invention, there is provided a method for sealing an oil filling pipe of a liquid ring type pressure sensor, wherein the first flat crushed end face is seam-welded while leaving a part to be sealed. After a lapse of a predetermined time from the completion of the second seam welding, the entire sealed portion is seam-welded, and the tip of the oil filling pipe is completely sealed by the second seam welding.

According to a third aspect of the present invention, there is provided a method of sealing an oil filling pipe of a liquid ring type pressure sensor, wherein a laser beam with a small diameter beam is scanned and irradiated to perform seam welding.

According to a fourth aspect of the present invention, there is provided a method for sealing an oil filling pipe of a liquid ring type pressure sensor, wherein a laser beam of a long elliptical beam is radiated over the entire portion of the flat crushed end face to be sealed. Thus, the entirety of the portion to be sealed is welded and sealed at a stroke, and the tip of the oil filling pipe is completely sealed by one-shot irradiation.

According to a fifth aspect of the present invention, there is provided a method for sealing an oil filling pipe of a liquid ring type pressure sensor, comprising the steps of sealing an oil filling pipe for filling a liquid ring chamber of the liquid ring type pressure sensor with oil. In the stopping method, the tip of the oil filling pipe is crushed flat, and the entirety of the sealed portion is irradiated by irradiating laser light with an oblong beam over the entire sealed portion of the flat crushed end surface of the pipe tip. This is a method of welding and sealing all at once, and completely sealing the tip of the oil filling pipe with one shot irradiation.

According to the sealing method according to the first aspect of the present invention, a temporary sealing portion is provided in the vicinity of the tip of the oil filling pipe by crushing in a streak shape in a cross direction of the pipe. Is prevented from flowing out of the oil filling pipe during the sealing step. Also, since the tip side of the temporarily sealed portion is crushed flat, a large amount of oil does not exist in that portion, and the oil in the pipe is welded or soldered to the sealed portion of the flat crushed end face of the pipe tip. A large amount is not blown out, and the blowout oil does not cause incomplete sealing by welding or the like.

According to the second aspect of the present invention, the first seam welding is performed while leaving a part of the flat crushed end face to be sealed, so that the first end of the seam welding is formed at the end of the temporary sealing portion. Even if oil remains in the flattened crushed part, the oil escapes from the non-seam welded part, so that the second seam welding performed after the elapse of a predetermined time does not blow out the oil, and the welding sealing is reliably performed. Done.

According to the sealing method according to the third aspect of the present invention, the above seam welding is reliably performed by scanning and irradiating a laser beam with a small diameter beam.

According to the sealing method of the fourth aspect of the present invention, the laser beam of the elliptical beam is irradiated over the entire area of the crushed end face to be sealed, so that the entirety of the sealed portion is welded and sealed at once. It is performed that the tip of the oil filling pipe is completely sealed by one shot irradiation, and even if oil remains in the flat crushed part on the tip side from the temporary sealing part for the flash welding,
It is performed without oil squirting.

According to the sealing method of the fifth aspect of the present invention, the tip of the oil filling pipe is crushed flat so that the oil flows out of the oil filling pipe during the sealing step by welding. And the laser light by the long elliptical beam is irradiated over the entire sealed portion of the crushed end face, and the entire sealed portion is welded and sealed at a stroke, and the oil filling pipe is irradiated with one shot. Since the tip is completely sealed and the flash welding is performed, even if oil remains in the flat crushed portion on the tip side of the temporary sealing portion, the oil is reliably blown out without being blown out.

[0018]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

1 and 2 show one embodiment of a pressure-sealed pressure sensor to which the method for sealing an oil filling pipe according to the present invention is applied.

The liquid ring type pressure sensor comprises a combination of a pressure detecting element 10, a joint 20, and a connector housing 30.

The pressure detecting element 10 has a metal element body 11 and a central opening 1 of the element body 11.
2, hermetic glass 13 is fixed. An outer peripheral edge of a metal diaphragm 14 is hermetically fixed to one end face (lower bottom face) of the pressure detecting element 10 by welding, and a diaphragm protection cover 15 having a communication hole 16 is attached below the outer periphery. With this structure, between the hermetic glass 13 and the metal diaphragm 14 at the central opening of the element body 11,
A liquid sealing chamber 17 in which oil is sealed is defined.

A sensor chip 40 having a one-chip structure is fixedly mounted on the surface of the hermetic glass 13 on the side of the liquid sealing chamber 17 with an adhesive. The sensor chip 40 is located in the liquid sealing chamber 17 and is configured as a one-chip sensor chip using a Piazo resistance pressure sensor or the like.

A plurality of lead pins 18 for inputting and outputting signals to and from the sensor chip 40 and an oil filling pipe 19 are fixed to the hermetic glass 13 in a penetrating state by hermetic processing.

The lead pin 18 is electrically connected to the sensor chip 40 by a gold or aluminum wire (not shown), and forms an external output terminal and an external input terminal of the sensor chip 40. FP is connected to the lead pin 18
C (flexible printed circuit) 31 is conductively connected,
The FPC 31 and the connection terminal 31 of the connector housing 30 are electrically connected.

The oil filling pipe 19 is used as a filling port for filling the liquid sealing chamber 17 with oil, and the tip is liquid-tightly sealed after the oil filling is completed.

Next, one embodiment of a method of sealing the oil filling pipe 19 according to the present invention will be described with reference to FIGS.

(1) Near the tip of the oil filling pipe 1
9a is crushed in a streak shape in the transverse direction of the pipe to provide a temporary sealing portion 50, and the tip side of the temporary sealing portion 50 is crushed flat to form a flat crushed portion 51. The temporary sealing portion 50 and the flat crushing portion 51 can be provided by the same simultaneous crushing process.

The temporary sealing portion 50 can be a V-groove-shaped streak-like crushing portion in order to obtain a sufficient temporary sealing contact pressure.
The flat dimension t of the flat crushed portion 51 is the oil filling pipe 1
9 is about 0.2-0.3 mm, 0.4-
About 0.6mm, the allowable flat crush gap a of the pipe inner diameter part a
Is preferably 0.01 mm or less (FIG. 4A).
reference).

(2) A sealed portion 53 of the flat crushed end surface 52 at the tip of the pipe (a flat crushed portion of the inner diameter portion of the pipe) is sealed by welding or soldering. The procedure for sealing the sealed portion 53 will be described.

(A) First seam welding W1: FIG.
As shown in (b), the sealed portion 53 of the flat crushed end face 52 is subjected to seam welding W1 except for a part 53a. (B) Second seam welding W2: As shown in FIG. 4C, after a lapse of a predetermined time from the completion of the first seam welding, the entire sealed portion 53 is seam-welded W2.
The end of the oil filling pipe is completely sealed by the second seam welding W2.

The first seam welding W1 and the second seam welding W2 can be performed by scanning and irradiating a laser beam with a small beam Ba. In this case, the small beam Ba
Is about 0.3 mm, and the scanning irradiation may be started from one end of the sealed portion 53. The size of the portion 53a where the first seam welding W1 is not performed may be equivalent to the beam diameter of the small-diameter beam Ba. In the second seam welding W2, only a part 53a may be welded in principle. However, in order to increase the reliability of the welding sealing, one end of the sealed portion 53 is again overlapped. May be done.

According to the above-described sealing method, the temporary sealing portion 50 is provided in the vicinity of the tip end 19a of the oil filling pipe 19 by crushing in a streak shape in the transverse direction of the pipe.
Oil filling pipe 1 during the sealing process by welding and soldering
It is possible to prevent oil from flowing out.

Further, since the distal end side of the temporary sealing portion 50 is crushed flat, a large amount of oil does not exist in that portion, and the sealed portion 5 of the flat crushed end face 52 at the tip of the pipe is crushed.
A large amount of oil in the pipe is not blown out at the time of welding or soldering of 2, and the blow-out oil does not cause incomplete sealing by welding or the like.

Moreover, since the first seam welding W1 is performed while leaving the portion 52a to be sealed 52, the oil remains in the flat crushed portion 51 on the distal end side of the temporarily sealed portion 50. However, the oil escapes from the portion 52a where the seam welding is not performed, so that the second seam welding W2 performed after a short time does not blow out the oil,
Weld sealing is ensured.

As a result, a highly reliable and reliable pipe sealing without oil leakage for a long period of time is performed.

Next, another embodiment of welding sealing of the sealed portion 53 in the method of sealing the oil filling pipe 19 according to the present invention will be described with reference to FIG. Also in this embodiment, (1) processing a temporary sealing portion near the tip of the oil filling pipe is the same as in the above-described embodiment.

In this embodiment, the oblong beam condensing lens 60 is used, and the sealed portion 53 of the flat crushed end face 52 is used.
The entirety of the sealed portion 53 is welded and sealed at a stretch by irradiating a laser beam with the long elliptical beam Bb over the entire region, and the tip of the oil filling pipe is completely sealed by one-shot irradiation.

In this case, since oil is left in the flat crushed portion 51 on the tip side of the temporary sealing portion because of the flash welding, the oil does not blow out, and the welded seal at the pipe tip can be reliably sealed. Done.

In this embodiment, the flat crushed portion 5
By performing the flat crushing 1 strongly, the flat crushing portion 51 is used as a temporary sealing portion, and even if the flat dimension t of the flat crushing portion 51 becomes small, it is possible to cope with it. This is because, if the beam Ba is a small beam, the beam diameter becomes too small due to the decrease in the flat dimension t, causing a problem of poor welding. However, such a problem does not occur if the elliptical beam Bb is used. is there.

Therefore, in this case, the provisional sealing portion 50 in the form of a V-groove crushed in a streak shape in the transverse direction of the pipe as described in the embodiment on the left is omitted, and the flat crushing is performed strongly. The obtained flat crushed portion 51 can be replaced with this.

[0041]

As will be understood from the above description, according to the sealing method according to the first aspect of the present invention, a temporary collapse due to a streak-like crush in the transverse direction of the pipe is provided near the tip of the oil filling pipe. Since the sealing portion is provided, it is possible to prevent the oil from flowing out from the oil filling pipe during the sealing process by welding and soldering, and since the tip side of the temporary sealing portion is flattened and crushed, such a portion is provided. There is no large amount of oil in the pipe, and a large amount of oil in the pipe does not blow out during welding or soldering of the sealed part of the flat crushed end face of the pipe tip, and the blowout oil causes incomplete sealing by welding etc. Never be. As a result, reliable and reliable pipe sealing without oil leakage for a long period of time is performed.

According to the sealing method according to the second aspect of the present invention, the first seam welding is performed while leaving a part of the flat crushed end face to be sealed. Even if oil remains in the flat crushed part on the side, oil escapes from the non-seam welded part, so that in the second seam welding performed after a lapse of a predetermined time, oil does not blow out, and the welding seal is securely performed. Done. As a result, reliable and reliable pipe sealing without oil leakage for a long period of time is performed.

According to the sealing method according to the third aspect of the present invention, the above seam welding is reliably performed by scanning and irradiating a laser beam with a small-diameter beam.

According to the sealing method of the fourth aspect of the present invention, a laser beam of a long elliptical beam is irradiated over the entire sealed portion of the crushed end face, and the entire sealed portion is welded at once. It is performed that the tip of the oil filling pipe is completely sealed by one shot irradiation, and even if oil remains in the flat crushed part on the tip side from the temporary sealing part for the flash welding,
It is performed without oil squirting. As a result, reliable and reliable pipe sealing without oil leakage for a long period of time is performed.

According to the sealing method of the fifth aspect of the present invention, the tip of the oil filling pipe is crushed flat so that the oil flows out of the oil filling pipe during the sealing step by welding. And the laser light by the long elliptical beam is irradiated over the entire sealed portion of the crushed end face, and the entire sealed portion is welded and sealed at a stroke, and the oil filling pipe is irradiated with one shot. Since the tip is completely sealed and the flash welding is performed, even if oil remains in the flat crushed portion on the tip side of the temporary sealing portion, the oil is reliably blown out without being blown out. As a result, reliable and reliable pipe sealing without oil leakage for a long period of time is performed.

[Brief description of the drawings]

FIG. 1 is an overall sectional view showing an embodiment of a pressure-sealed pressure sensor to which a method for sealing an oil filling pipe according to the present invention is applied.

FIG. 2 is an enlarged sectional view of a pressure detecting element of a pressure-sealed pressure sensor to which the method for sealing an oil filling pipe according to the present invention is applied.

FIG. 3A is a sectional view showing an embodiment of a method for sealing an oil filling pipe according to the present invention, and FIG. 3B is an enlarged sectional view of a main part thereof.

FIGS. 4A to 4C are cross-sectional views showing an embodiment of a method for sealing an oil filling pipe according to the present invention.

FIG. 5 is a sectional view showing another embodiment of the method for sealing an oil filling pipe according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pressure detection element 11 Element main body 13 Hermetic glass 14 Metal diaphragm 15 Diaphragm protection cover 17 Liquid seal chamber 19 Oil filling pipe 20 Joint 30 Connector housing 32 Connection terminal 50 Temporary sealing part 51 Flat crushed part 52 Flat crushed end face 53 Sealed Stop part 60 Long elliptical beam focusing lens

Claims (5)

[Claims] 1. A method for sealing an oil filling pipe for filling oil into a liquid sealing chamber of a liquid ring type pressure sensor, comprising: crushing a portion near a tip of the oil filling pipe into a streak shape in a transverse direction of the pipe. And providing a temporary sealing portion by crushing the tip side of the temporary sealing portion flat, and sealing the sealed portion of the flat crushed end surface of the pipe end by welding or soldering. For sealing the oil filling pipe of the pressure sensor. 2. The seam welding is performed on a part of the flat crushed end face that is to be sealed while leaving a part thereof, and after a lapse of a predetermined time from the completion of the first seam welding, the entirety of the sealed part is seam-welded, The method for sealing an oil filling pipe of a liquid ring type pressure sensor according to claim 1, wherein the tip of the oil filling pipe is completely sealed by the second seam welding. 3. The method for sealing an oil filling pipe of a liquid ring type pressure sensor according to claim 2, wherein seam welding is performed by scanning and irradiating a laser beam with a small diameter beam. 4. An oil filling pipe by irradiating a laser beam with a long elliptical beam over the entire area of the sealed portion of the flat crushed end face to weld and seal the entire sealed portion at a stroke, and by one-shot irradiation. 2. The method for sealing an oil filling pipe of a liquid ring type pressure sensor according to claim 1, wherein the tip of the oil filling pipe is completely sealed. 5. A method for sealing an oil filling pipe for filling oil into a liquid sealing chamber of a liquid ring type pressure sensor, wherein a tip of the oil filling pipe is crushed flat, and a flat crushed end face of the tip of the pipe is provided. Irradiating a laser beam with a long elliptical beam over the entire portion to be sealed to weld and seal the entire portion to be sealed at once, and completely sealing the tip of the oil filling pipe by one shot irradiation. A method for sealing an oil filling pipe of a liquid ring type pressure sensor.