JP2662498B2 - Diaphragm and acceleration sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm and an acceleration sensor using the diaphragm.

[0002]

2. Description of the Related Art Conventionally, there has been known a diaphragm in which a diaphragm is deformed by a working fluid and a movable portion is moved by the deformation of the diaphragm.

[0003] Among such diaphragms, there is a diaphragm formed in a corrugated shape so that the diaphragm plate is easily elastically deformed.

On the other hand, an acceleration sensor shown in FIG. 16 is known which is used to detect the acceleration of a vehicle.

In FIG. 16, reference numeral 1 denotes a metallic case which is attached to a base 2 by welding, and the inside of the case 1 is in a sealed state. Base 2 in case 1
Is provided, and a thin-film resistor or the like is formed on the ceramic substrate 3. An acceleration detecting element 5 made of a semiconductor for detecting acceleration is mounted on the ceramic substrate 3 via a pedestal 4 made of silicon in a cantilevered manner.

Silicone oil 6 for damping the acceleration detecting element 5 is sealed in the case 1 to absorb the expansion and contraction of the silicon oil 6 due to a temperature change, thereby causing problems such as leakage of the silicon oil. Is provided in the case 1. Reference numeral 8 denotes an adhesive on which the sponge 7 is attached to the case 1.

[0007] A strain gauge 5a is formed in the acceleration detecting element 5, and the tip 5b of the element 5 swings in the direction of arrow A, so that the strain gauge 5a is distorted. This strain changes the resistance value of the strain gauge 5a, and the acceleration is detected from the change in the resistance value. The direction indicated by the arrow is the direction in which acceleration is applied.

[0008]

The diaphragm plate is formed in a wave shape so as to be easily elastically deformed. However, since the wave height and pitch of the wave are constant, the displacement of the center of the diaphragm plate is not sufficient. It was not something. For this reason, there is a problem that if the displacement of the central portion is increased, the diaphragm becomes large.

Further, the acceleration sensor is provided with a sponge 7 for absorbing the expansion and contraction of the silicone oil 6 due to a temperature change. However, the sponge 7 cannot follow the contraction of the silicon oil 6 in a low temperature state. The gas in 7 leaks into silicon oil 6 to generate bubbles. The bubbles adhere to the surface of the acceleration detection element 5 and change the frictional characteristics between the surface of the acceleration detection element 5 and the silicone oil 6,
Therefore, the amount of shake of the tip 5b of the acceleration detecting element 5 changes. As a result, the strain amount of the strain gauge 5a changes, and the output characteristics of the acceleration detecting element 5 fluctuate, resulting in a problem that accurate acceleration cannot be detected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a diaphragm capable of increasing the displacement of a central portion, and a diaphragm using the diaphragm.
It is an object of the present invention to provide an acceleration detection sensor that does not generate bubbles in a fluid sealed in a case.

[0011]

According to the first aspect of the present invention, in a diaphragm provided with a diaphragm plate which is deformed by pressure, a corrugation is formed on the diaphragm plate from a center portion to a peripheral portion thereof. The characteristic feature is that the wave height and pitch are increased as going toward the center.

According to a second aspect of the present invention, in the acceleration sensor, an acceleration detecting element for detecting acceleration is provided in a sealed case, and a fluid for damping the acceleration detecting element is sealed in the case. A deformable diaphragm portion is provided in the case, a waveform is formed in the diaphragm portion from the center portion to the peripheral portion, and the wave height and pitch of the wave are increased as going to the center portion, and by the deformation of the diaphragm portion It is characterized in that a change in volume due to a change in temperature of the fluid is absorbed.

[0013]

[0014]

[0015]

According to the first aspect of the present invention, the diaphragm plate is formed in a wave shape from the center to the periphery, and the wave height and pitch of the wave are increased as going toward the center. Greatly displaces.

According to the second aspect of the present invention, the deformable diaphragm portion provided in the case is formed in a wave shape from the center to the peripheral portion, and the wave height and pitch of the wave are increased as going toward the center. In addition, the diaphragm portion is largely elastically deformed, thereby absorbing a volume change due to a temperature change.

[0017]

[0018]

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the acceleration sensor according to the present invention will be described below with reference to the drawings.

1 and 2, reference numeral 11 denotes a base 1
2 is a metallic case attached by welding, and the inside of the case 11 is in a sealed state. As shown in FIG. 3, a diaphragm (deformed portion) 11a is formed on the side plate 11A of the case 11, and the diaphragm 11a is formed.
Is deformed according to the pressure in the case 11 so that the volume in the case 11 changes.

A ceramic substrate 13 fixed to a base 12 is provided in the case 11, and a thin film resistor (not shown) and the like are formed on the ceramic substrate 13.
The ceramic substrate 13 has a tantalum capacitor C1
And a ceramic capacitor C2 and the like.

Further, an acceleration detecting element 15 made of a semiconductor for detecting acceleration is mounted on the ceramic substrate 13 via a pedestal 14 made of silicon in a cantilevered state.

As shown in FIG. 4, the acceleration detecting element 15 has a strain gauge portion 15a formed therein.
The strain gauge portion 15a is distorted by the deflection of the strain gauge 15b in the direction of the arrow due to the acceleration, and the acceleration is detected from the change in the resistance value of the strain gauge 15a due to the strain.

Silicone oil (fluid) for damping vibration of the acceleration detecting element 15 is provided in the case 11.
16 are enclosed.

1 and 2, reference numeral 17 denotes a lead pin, 18 denotes molten glass, and 19 denotes a mounting hole.

The acceleration sensor configured as described above
When the silicone oil 16 expands and contracts due to a temperature change, the diaphragm portion 11a is deformed so as to protrude upward from the position shown in FIG. Due to this deformation, the volume in the case 11 fluctuates to absorb the fluctuation in the volume of the silicone oil 16, thereby preventing a problem caused by the fluctuation in the volume of the silicon oil 16.

The diaphragm portion 11a is only deformed by expansion and contraction due to a temperature change of the silicon oil 16, and no gas is generated unlike the conventional case because no sponge is used. No bubbles are generated. Therefore, the output characteristics of the acceleration detecting element 15 do not change, and accurate acceleration can be detected.

FIG. 5 shows a second embodiment. In this embodiment, a diaphragm (sealed body) 21 in which a gas 20 is sealed is provided in a case 11. The diaphragm body 21 includes a mounting plate 22 attached to the side plate 11A of the case 11 and a diaphragm plate 23 having a diaphragm 23a. Diaphragm plate 23
Is attached to the mounting plate 22 by welding or brazing, etc.
Is sealed.

The diaphragm 21 is made of silicone oil 1
6 is absorbed by contracting and expanding the gas 20 in the diaphragm 21. Since the gas 20 is sealed, bubbles are not generated in the silicone oil 16 when the silicone oil 16 expands and contracts.

FIG. 6 shows a third embodiment. In this embodiment, a sealing body 32 in which the gas 20 is sealed by elastic materials 30 and 31 such as rubber is formed. It is attached. The elastic member 30 is attached to the side plate portion 11A with an adhesive, and the elastic members 30 and 31 are attached with an adhesive.

FIG. 7 shows an example in which the elastic member 31 is attached to the side plate 1 of the case 11.
The sealing body 34 is formed by directly attaching the sealing body 34 to the sealing member 1A.

FIGS. 8 to 11 show a fourth embodiment. In this embodiment, the area in contact with the silicon oil 16 is increased and the two diaphragm plates 51 and 5 are used.
1 is formed in a container shape and closely adhered to each other to form a sealed body 50. In this embodiment, two diaphragm plates 51, 5
Since the number 1 is deformed, the volume change of the sealed body 50 can be increased even if the amount of deformation per sheet is small.

The diaphragm 51 has a corrugation (diaphragm) 52 extending from the center to the periphery, and the flange 51 a of the diaphragm 51 is attached to the step 61 of the cap 60. This is mounted by spot welding or the like.

As shown in FIG. 12, the wave heights h1 to h6 and the pitches P1 to P6 of the corrugations 52 formed on the diaphragm plate 51 are set larger toward the center as shown in FIG. By setting in this way, the spring constant at the center increases, and the center displaces greatly. That is, even if the sealing body 50 is small, the volume is largely deformed, so that the size of the acceleration sensor can be reduced.

In FIG. 12, if the initial value is P1 and the series magnification is XP, the pitch Pn between the waves is Pn = P1 × XP ^n-1 .

Further, the line connecting the vertices of each wave is set to be a straight line. If the magnification of the wave height is Xh, then Xh = h6 / h1. The wave number is R / N = 1 ± 30%.

Under these conditions, the diaphragm 5
As a result of simulating a value at which the stress distribution of No. 2 becomes uniform and the displacement at the center of the diaphragm portion 52 becomes maximum, Xp = 1.1 P1 = 0.534 Xh = 3 h1 = 0.15 It was found that the tolerance was within the range of 30%, that is, Xp = 1.1 ± 30% and Xh = 3 ± 3.
0%, h1 / R = 0.027 ± 30%).

This indicates that the stress distribution of the diaphragm portion 52 is uniform, that is, each portion is elastically deformed over the entire diaphragm portion 52. As a result, it is possible to prevent the stress from being concentrated on a specific portion and causing the diaphragm portion 52 to be damaged or cracked.

When the displacement of the diaphragm portion 52 is small, for example, when only the peripheral portion of the diaphragm portion 52 is elastically deformed, the displacement of the center portion of the diaphragm portion 52 is small (since other portions are not elastically deformed), Stress concentration occurs in the surrounding area (when the center area and its vicinity are viewed, the center area is not elastically deformed relative to the vicinity. Therefore, no stress is generated at the boundary between the center area and the vicinity). As a result, the surrounding area is damaged or cracked.

Further, since the stress distribution is made uniform, the displacement of the center of the diaphragm 52 can be maximized. Therefore, the displacement of the diaphragm portion 52 can be sufficiently ensured without increasing the size of the diaphragm plate 51. That is, even if the sealing body 50 is small, the change in volume can be increased, the size of the acceleration sensor can be reduced, and the operating temperature range can be widened.

FIGS. 13 and 14 show a cap 70 according to another embodiment. In this embodiment, the cap 70 is used.
It is only necessary to squeeze the four corners, so that the production of the cap 70 is easy. 71 is a step part.

FIG. 15 shows a fifth embodiment. In this embodiment, two sealing bodies 80 and 90 are attached to the cap 60.

The sealing member 80 is constituted by one diaphragm plate 51, and the sealing member 90 is constituted by two flange plates 51,51. According to this embodiment, since the two seals 80, 90 are attached to the cap 60, the volume of the two seals 80, 90 changes greatly, so that the operating temperature range can be further widened. .

In the above embodiment, the case where the diaphragm plate 51 is used for the acceleration sensor has been described. However, it is needless to say that the diaphragm plate 51 may be used as another diaphragm. Also in this case, since the diaphragm portion 52 is largely displaced, the size of the diaphragm can be reduced.

[0045]

According to the present invention, the diaphragm plate
Since it was formed in a wave shape from the center to the periphery and the wave height and pitch of the wave were increased as going to the center,
The center of the diaphragm plate is largely displaced, and the size of the diaphragm can be reduced.

According to the invention, there is provided an acceleration sensor in which an acceleration detecting element for detecting acceleration is provided in a sealed case, and a fluid for damping the acceleration detecting element is sealed in the case. A deformable diaphragm portion was provided in the case, and the diaphragm portion was formed in a corrugated shape from the center to the peripheral portion, and the wave height and pitch of the wave were increased as going toward the center. The displacement increases. That is,
The volume change of the sealed body can be increased, and as a result,
The operating temperature range of the acceleration sensor can be widened.

[0047]

[Brief description of the drawings]

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

FIG. 2 is a plan view showing a cross section of a part of the acceleration sensor shown in FIG.

FIG. 3 is an explanatory view showing a diaphragm portion of a case.

FIG. 4 is an explanatory diagram showing an acceleration detecting element.

FIG. 5 is a sectional view showing a second embodiment.

FIG. 6 is a sectional view showing a third embodiment.

FIG. 7 is a sectional view showing another embodiment of the third embodiment.

FIG. 8 is a sectional view showing a fourth embodiment.

FIG. 9 is a plan view showing a diaphragm plate.

FIG. 10 is a plan view showing a cap.

FIG. 11 is a side view of the cap.

FIG. 12 is an enlarged sectional view of a part of the diaphragm plate.

FIG. 13 is a plan view showing another cap.

FIG. 14 is a side view of the cap of FIG.

FIG. 15 is a sectional view showing a fifth embodiment.

FIG. 16 is a cross-sectional view showing a configuration of a conventional acceleration sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Case 11a Diaphragm part (deformation part) 15 Acceleration detecting element 16 Silicon oil (fluid) 21 Diaphragm body (sealed body) 32,34 Sealed body 51 Diaphragm plate

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-174363 (JP, A) JP-A-4-181170 (JP, A) JP-A-3-162676 (JP, A) JP-A-50- 52621 (JP, A) JP-A-63-225706 (JP, A) JP-A-5-187548 (JP, A) JP-A-2-195082 (JP, A) JP-A-7-110010 (JP, A) JP-A-5-26899 (JP, A) JP-A-5-107261 (JP, A) JP-A-57-13362 (JP, A) JP-A-3-170064 (JP, A) (JP, U) JP-A 4-79266 (JP, U) JP-A 62-193566 (JP, U) JP-B 58-29876 (JP, B2) JP-B 34-4403 (JP, B1) 48-39477 (JP, Y1) Jiko 56-9878 (JP, Y2)

Claims (2)

(57) [Claims] 1. A diaphragm provided with a diaphragm plate which is deformed by pressure, wherein the diaphragm plate has a corrugation formed from a central portion to a peripheral portion, and the wave height and pitch of the wave increase as going toward the central portion. A diaphragm characterized by having done. 2. An acceleration sensor in which an acceleration detecting element for detecting acceleration is provided in a sealed case, and a fluid for damping the acceleration detecting element is sealed in the case. A diaphragm portion is provided, and the diaphragm portion is formed into a corrugated shape from the center to the peripheral portion, and the wave height and pitch of the wave are increased toward the center, and the temperature of the fluid is changed by the deformation of the diaphragm. An acceleration sensor characterized by absorbing a change in volume due to a change.