JPH0961162A - Tilt sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tilt sensor which is constituted of a container body comprising a recessed part and of a ceiling plate comprising a spherical recessed face used to close the recessed part and in which the spherical recessed face on the ceiling plate is positioned in a prescribed position with reference to a holder when an airtight container in which a liquid used to form an air bubble is sealed at the inside is used as a bubble tube. SOLUTION: An airtight container A is constituted in such a way that a ceiling plate 3 whose rear surface is formed to be a spherical recessed face 3a, a cylindrical member 2 and a bottom plate 1 are bonded coaxially. An electrolytic solution L which forms an air bubble B is sealed up inside the airtight container A. Electrodes 4, 5, 6 which detect the position of the air bubble B as a change in an electric resistance between the spherical recessed face 3a and the surface 1a of the bottom plate 1 inside the airtight container A are formed respectively on the spherical recessed face 3a and on the surface 1a of the bottom plate 1 inside the container. An inside flange 7c is installed inside a holder 7 into which the airtight container A is inserted. The flange is made longer than the length between the edge part of the spherical recessed face 3a and the rear surface of the bottom plate 3 inside the airtight container A. When the airtight container A is inserted into the holder 7, the edge part of the spherical recessed face 3a on the ceiling plate 3 is brought into contact with the inside flange 7c so as to be positioned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tilt sensor in which a cylindrical closed container in which a liquid is closed together with bubbles is fixed in a holder.

[0002]

2. Description of the Related Art Conventionally, as an inclination sensor for detecting the inclination of a surveying instrument, an aircraft, an automobile, etc., an inclination sensor showing an inclination angle based on the position of bubbles in a liquid sealed in a bubble tube has been used. ing. Such a conventional tilt sensor is shown in FIG.

In FIG. 8, on the upper surface of the holder 50 of the tilt sensor, holding stands 51, 51 having a concave shape when viewed from the side are integrally formed. The bubble tube 52 is placed on the holding bases 51, 51. This bubble tube 52
Is composed of a glass tube bent to have the highest height in the center thereof, and a liquid L forming a bubble B is enclosed therein. The bubble tube 52 is positioned so that the bubble B is located at the center when the holder 50 is in a horizontal state, and is fixed to the holder 50 by a clasp 54 via a spacer 53. The holder 50 is fixed to a tilt detection target such as a surveying instrument (not shown) by a set screw (not shown) inserted into the fixing holes 55a, 55a of the fixing portion 55 formed on the lower surface of the holder 50. Then, the position of the bubble is electrically detected by an electrode formed on the inner surface or the outer surface (not shown) of the bubble tube 52, and is used as an electric signal indicating the inclination angle of the inclination detection target.

By the way, the applicant has previously applied for an invention in which a closed container used as a bubble tube is composed of a plurality of parts in order to facilitate the production of the bubble tube (Japanese Patent Application No. Hei 5-
315863). The structure of this closed container is shown in FIG.

In FIG. 9, a top plate 60 is composed of a plano-concave lens, and upper electrodes 63, 63 having a symmetrical shape with respect to the central axis are formed on the spherical concave surface by platinum thin film coating. The bottom plate 62 is made of disk-shaped parallel flat glass, and the lower electrode 64 is formed by platinum thin film coating over the entire upper surface thereof. In addition,
The cylindrical member 61 is a glass tube having an outer diameter slightly smaller than the outer shapes of the top plate 60 and the bottom plate 62.

Then, the top plate 60 is attached to the upper end surface of the cylindrical member 61 by a glass paste adhesive so that the electrodes 63, 63 are exposed inside the cylindrical member 61. A bottom plate 62 is similarly attached to the lower end surface of the cylindrical member 61 so that the electrode 64 is exposed inside the cylindrical member 61. The electrolytic solution L is enclosed in the airtight container created in this manner, leaving only the amount of air for forming the bubbles B.

When a voltage is applied between the upper electrodes 63, 63 and the lower electrode 64 in the sealed container thus constructed, each upper electrode 6 of the electrolytic solution L is changed depending on the position of the bubble B.
Since the contact area for 3, 63 changes, the resistance value between each of the upper electrodes 63, 63 and the lower electrode 64 changes. This change in resistance value is detected by a detection circuit (not shown) as a signal indicating the inclination angle of the closed container. Therefore, in the case of the sealed container having such a structure, both end surfaces of the cylindrical member 61 are orthogonal to the central axis so that the upper electrodes 63, 63 and the lower electrode 64 are equidistant from each other. It is necessary to be formed so that

[0008]

However, in the above application, there is no description about how to fix the closed container configured as shown in FIG. 9 to the holder attached to the tilt detection target. It was

Therefore, for example, it is conceivable to apply the conventional fixing method for a bubble tube shown in FIG. 8 to the closed container of FIG. However, since the positioning in that case is performed with the lower surface of the bottom plate 62 as a reference, in order to position the bubble B between the upper electrodes 63, 63 when the holder is in the horizontal state (that is, In order to maximize the center position of the spherical concave surface of the top plate 60), the lower surface and the upper surface of the bottom plate 62 must be machined so as to be parallel to each other with high accuracy, which results in high manufacturing cost. become. In this case, the bottom surface of the bottom plate 62 is originally
It is unreasonable to increase the processing accuracy and the manufacturing cost, although it does not contribute to the accurate detection of the position of the bubble B.

Therefore, in view of the above problems, the present invention provides a liquid which forms a bubble while being composed of a container body having a concave portion and a top plate having a curved surface which gradually becomes deeper from the periphery of closing the concave portion toward the center. Even when using an airtight container enclosed inside it as a bubble tube, the curved surface of the top plate is positioned at a predetermined position with respect to the holder regardless of the processing accuracy of the bottom surface of the container body or the top surface of the top plate. It is an object to provide an inclination sensor that can be positioned in the.

[0011]

The invention described in each claim is
This is done to solve the above problems. The tilt sensor according to claim 1 has a container main body having a concave portion, a top plate having a curved surface that gradually becomes deeper from the periphery of closing the concave portion toward the center and having an outer diameter larger than the outer diameter of the container main body. And a closed container in which a liquid that forms bubbles is enclosed, and the curved surface of the top plate is formed in a state where the closed container is passed and the container main body is passed through. A holder for stably holding the surface on which the curved surface is formed by blocking the passage of the curved surface.
"By passing the container body of the closed container and blocking the passage of the surface of the top plate on which the curved surface is formed in the state of passing the container body, "Stable" means that there is a part (face, protrusion, etc.) that does not interfere with the passage of the container body but abuts the surface of the top plate on the container body side and interferes with its passage. This means that the plate is held in a fixed posture without causing play.

An inclination sensor according to a second aspect of the present invention has a container body having a recess and a curved surface that gradually becomes deeper from the periphery of closing the recess toward the center and outside the end of the container body where the recess is open. A sealed container having a top plate having an outer diameter larger than the diameter and enclosing a liquid forming bubbles therein, and the top plate abutting on the surface of the top plate on which the curved surface is formed. And a holder having a positioning portion for stably holding. The "positioning portion that abuts the surface of the top plate on which the curved surface is formed to stably hold the top plate" means to contact the surface of the top plate on the container body side and tilt the top plate. It is a part (face, protrusion, etc.) that can be held without a finger.

According to a third aspect of the present invention, the top plate of the second aspect has a circular flat surface, and the positioning portion has the curved surface of the top plate formed at least at three positions in the circumferential direction. It is characterized in that it abuts against the existing surface. That is, if the positioning means abuts on the flat surface of the top plate at least at three positions in the circumferential direction, the two can be positioned without play.

The invention according to claim 4 is characterized in that the positioning portion in claim 3 is composed of a plurality of arc-shaped projections having a common center point. That is, if it is formed in an arc shape, the contact area becomes wider, and thus stable holding can be achieved.

According to a fifth aspect of the present invention, the top plate in the second aspect has a circular flat surface, and the positioning portion is provided on a surface of the top plate on which the curved surface is formed. It is characterized in that it is composed of an abutting annular projection. That is, the annular projection can be held most stably.

According to a sixth aspect of the present invention, the positioning portion according to the fourth or fifth aspect is a flange formed on an inner peripheral surface of a concave portion formed in the holder for holding the closed container therein. There is a feature.

According to a seventh aspect of the present invention, in the container body according to any one of the first to sixth aspects, a cylindrical member that comes into contact with the surface of the top plate on which the curved surface is formed at one end surface thereof, It is characterized by comprising a bottom plate that closes the other end surface of this tubular member.

The invention according to claim 8 is characterized in that the liquid according to any one of claims 1 to 7 is an electrolytic solution. The invention according to claim 9 is characterized in that the top plate and the container body according to any one of claims 1 to 8 are made of glass. If these are made of glass, the position of the bubble can be visually detected.

The invention as defined in claim 10 is defined by claim 1 through claim 9.
The container body according to any one of items 1 to 5 is separated from the holder. If they are completely separated from each other, they do not hinder stable holding of the surface of the top plate on which the curved surface is formed.

The invention according to claim 11 is the invention according to any one of claims 1 to 1.
It is characterized by comprising a pressure contact means for pressing the top plate according to any one of 0 to the positioning portion. With this configuration, even if the tilt sensor vibrates, the closed container is stably held.

The invention according to claim 12 is the invention according to any one of claims 1 to 1.
The top plate according to any one of 1 above has a circular surface, and the curved surface is a spherical concave surface formed over the entire area of this surface. In this case, the holder (or the positioning portion thereof) may hold the edge of this curved surface.

The invention described in claim 13 is according to any one of claims 1 to 1.
The top plate according to any one of 1 has a circular flat surface, and the curved surface is a spherical concave surface formed only in a portion of the flat surface facing the concave portion of the container body. , Characterized.

An inclination sensor according to a fourteenth aspect has a container main body having a concave portion and a curved surface that gradually becomes deeper from the periphery of closing the concave portion toward the center and has an outer diameter larger than the outer diameter of the container main body. And a holder having a recess for accommodating the closed container, and a smaller diameter than the outer diameter of the top plate. While having an inner diameter larger than the inner diameter of the container body, the distance from the bottom of the recess is longer than the distance from the surface of the top plate on which the curved surface of the container body is formed to the end of the container body. A flange formed on the inner peripheral surface of the recess at a position.

An inclination sensor according to a fifteenth aspect is characterized in that an electrode for detecting the position of the bubble as the electric resistance of the electrolyte is formed on the curved surface and the bottom surface of the recess.

The container body may be integrally molded. In addition, when electrically detecting the position of the bubble in the closed container, a method of detecting by the change of the capacitance of the liquid may be adopted. In this case, a liquid having a large dielectric constant is used as the liquid sealed in the closed container, and the electrodes are formed on the outer surface of the top plate and the outer surface of the bottom of the container body. Whether the method of detecting the position of the bubble by the change of the electrostatic capacity or the method of detecting the change of the resistance value as in claim 8 is used, the upper electrode formed on the top plate is inclined. It is formed as two electrodes which are arranged symmetrically with respect to the center position of the top plate along the measuring direction and are insulated from each other. Further, when the directions of measuring the inclination are two directions orthogonal to each other, the four electrodes formed at mutually rotationally symmetrical positions are used as the upper electrodes. The curved surface that gradually becomes deeper from the periphery to the center may be an arch, or a quadric surface, especially a rotating surface, as long as the bubble position moves according to the inclination of the top plate. Is also good. When used as a surface of revolution, it may be spherical, ellipsoid of revolution, hyperboloid of revolution, or paraboloid of revolution.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

[0027]

First Embodiment <Mechanical Configuration of Tilt Sensor> FIG. 3 is a top view of a tilt sensor according to a first embodiment, and FIG.
FIG. 2 is a cross-sectional view showing a vertical cross section along line I, and FIG. 2 is a cross-sectional view showing a vertical cross section similarly along line II-II.

In each figure, the inclination sensor is a closed container A,
It comprises a holder 7 for holding the closed container A therein, a lid 8 for closing the holder 7 and pressing the closed container A against the holder 7, and a cover 9 for covering the holder 7 and the lid 8. Details of these components will be described below. (Closed container) The closed container A is composed of a cylindrical member 2 and a top plate 3 and a bottom plate 1 adhered to upper and lower ends of the cylindrical member 2.
It is configured. The cylindrical member 2, the top plate 3, and the bottom plate 1 are all formed of a highly insulating material such as lead glass, and are bonded to each other in a liquid-tight manner with an adhesive such as a glass paste.

The top plate 3 is a transparent plate having a plano-concave lens shape. That is, the upper surface of the top plate 3 is a circular flat surface. In addition, the lower surface has a radius of curvature R = 300 [m
m], which is a spherical concave surface 3a that is concave in a spherical shape, and forms the inner surface of the closed container A. That is, this lower surface is the top plate 3
The spherical concave surface 3a corresponds to the surface formed over the entire surface. The peripheral surface of the spherical concave surface 3a is formed into a columnar shape centered on a perpendicular line standing at the deepest point, and its outer diameter is 21 [mm].

The spherical concave surface 3a of the top plate 3 (curved surface that gradually becomes deeper from the periphery toward the center) 3a is finished to a rough surface having an appropriate roughness with, for example, # 1000 abrasive.
A first upper electrode 4 and a second upper electrode 5 made of a platinum thin film are formed on the spherical concave surface 3a. These upper electrodes 4 and 5 are formed line-symmetrically with respect to a line (a line oriented in the y direction in FIG. 4) which is erected on the paper so as to pass through the deepest point (center point) of the spherical concave surface 3a in FIG. In addition, they are separated from each other with a certain width of space in between. The outer peripheral edge of each of the upper electrodes 4 and 5 has an arc shape that is coaxial with the peripheral surface of the top plate 3 and has the same diameter as the inner diameter of the cylindrical member 2. Part of the outer peripheral edge of each upper electrode 4, 5 is formed as a fan-shaped protrusion 4a, 5a having a diameter larger than the outer diameter of the cylindrical member 2 and smaller than the outer diameter of the spherical concave surface 3a. Each of the upper electrodes 4 and 5 is formed by masking the portion of the spherical concave surface 3a other than the electrode forming portion and depositing a platinum thin film by high frequency sputtering. After that, the platinum thin films forming the upper electrodes 4 and 5 are subjected to platinum black treatment. In addition, lead wires C are attached by soldering to the peripheral portions of the protruding portions 4a and 5a of the upper electrodes 4 and 5 that protrude to the outside of the cylindrical member 2 during assembly.

The bottom plate 1 is a disk-shaped transparent plate. That is,
The upper surface 1a and the lower surface 1b of the bottom plate 1 are planes parallel to each other. The peripheral surface is formed into a cylindrical shape coaxial with the top plate 3, and has an outer diameter of 19 [mm].

The upper surface 1a of the bottom plate 1 forms the bottom surface of the closed container A, and is finished to be a rough surface having an appropriate roughness with, for example, # 1000 abrasive. A lower electrode 6 made of a platinum thin film is formed on the upper surface 1a. The lower electrode 6 is formed in a circular shape coaxial with the bottom plate 1 and larger than the outer diameter of the cylindrical member 2 and slightly smaller than the outer diameter of the upper surface 1a. Similar to the case of the upper electrodes 4 and 5, the lower electrode 6 is formed by masking a portion other than the electrode forming portion on the upper surface 1a and depositing a platinum thin film by high frequency sputtering. Thereafter, the platinum thin film forming the lower electrode 6 is subjected to platinum black treatment. In addition, the lower electrode 6 protruding outside the cylindrical member 2 during assembly
A lead wire C is attached to the peripheral portion of the by soldering.

The cylindrical member 2 is composed of a glass tube having a uniform thickness, and its outer diameter is 15 [mm].
The upper and lower ends thereof are cut along a plane orthogonal to the central axis thereof, and are coaxially joined to the spherical concave surface 3a of the top plate 3 or the upper surface 1a of the bottom plate 1, respectively. The upper end surface of the cylindrical member 2 is formed as a spherical surface having the same curvature as that of the spherical concave surface 3a around a point existing on the extension line of the central axis thereof so as to be in close contact with the spherical concave surface 3a of the top plate 3. . The lower end surface of the cylindrical member 2 is formed as a flat surface so as to be in close contact with the upper surface 1a of the bottom plate 1. In addition,
The cylindrical member 2 is formed along with the bottom plate 1 into a recess (the cylindrical member 2
And a top surface 1a of the bottom plate 1). Therefore, it can be said that the end of the container body where the recess is open (the upper end of the cylindrical member 2) has a smaller diameter than the outer diameter of the top plate 3.

In the airtight container A constructed in this way, the electrolyte L is enclosed while leaving a quantity of air for forming bubbles B. The electrolytic solution L is, for example, a solution obtained by dissolving potassium iodide in methyl alcohol. This bubble B
As long as the deepest part of the spherical concave surface 3a of the top plate 3 is located at the highest position in the direction of gravity (that is, the edge of the spherical concave surface 3a of the top plate 3 is kept horizontal), other portions ( For example,
Even if the processing accuracy of the upper surface of the top plate 3, the angle of the end surface of the cylindrical member 2 with respect to the axis, and the direction of the lower surface 1b of the bottom plate 1) is insufficient, it is located at the center of the spherical concave surface 3a.
(Holder) The holder 7 is formed by cutting aluminum. Then, as shown in FIG. 3, when viewed from the upper surface side, two adjacent corners are largely chamfered, and the other two corners are formed into a substantially square plate shape with a small chamfer. On the upper surface of the holder 7, a cylindrical recess 7d having an inner diameter substantially the same as the outer diameter of the top plate 3 is formed around an axis 1 standing at the center position. Further, three fan-shaped support pillars 7a are formed around the recess 7d at equal angular intervals. The inner surfaces of the three support pillars 7a form extensions of the inner peripheral surface of the recess 7d. An inner flange 7c, which is an arc-shaped projection having a flange surface on the same plane orthogonal to the axis l, is formed on the inner surface of each of the support pillars 7a. This inner flange 7c
The inner diameter of is smaller than the outer diameter of the top plate 3 and larger than the outer diameter of the bottom plate 1. Also, this inner flange 7c
Flange surface (upper side surface in FIGS. 1 and 2) and recess 7d
Is larger than the distance between the peripheral edge of the spherical concave surface 3a in the closed container A and the lower surface 1b of the bottom plate 1. Therefore, the inner flange 7c serves as a positioning portion that abuts the spherical concave surface 3a of the top plate 3 and stably holds the top plate 3. In addition, the holder 7 having the inner flange 7c prevents the passage of the surface of the top plate 3 on which the spherical concave surface 3a is formed while allowing the container body of the closed container A to pass therethrough. Has a function of stably holding the surface on which the spherical concave surface 3a is formed,
You will have.

The end faces of the support pillars 7a are formed on the same plane orthogonal to the axis l. Female screw holes 7b are formed on the end faces of each of the support columns in a direction parallel to the axis l.

The peripheral portion of the upper surface of the holder 7 is
An annular band having the same diameter as the outer peripheral surface of each support column 7a is left around the axis 1 and is cut one step lower. As shown in FIG.
A rectangular attachment portion 10 is integrally formed so as to project from the edge portion of the holder 7 sandwiched between the small chamfered corners, and is bent 90 degrees downward (gravitational direction) from the middle as shown in FIG. . As shown in FIG. 1, two fixing holes 10a for inserting the fixing screws 11 for fixing the inclination sensor to the measurement object are formed side by side at the tip of the attachment portion 10. The fixing hole 10a has an inner diameter larger than the outer diameter of the shaft of the fixing screw 11. Therefore, when the tilt sensor is fixed to the measurement target, the tilt sensor can be slightly rotated in the plane of FIG. 1 to adjust the tilt. (Lid) The lid 8 is also formed by cutting aluminum into a disk shape having the same diameter as the outer peripheral surface of each of the support pillars 7a of the holder 7. The lid 8 has screw heads of flat head screws 13 screwed into the female screw holes 7b at three positions corresponding to the positions of the female screw holes 7b of the respective support columns 7a when placed on the respective support columns 7a. The spot facing 8c is formed. In addition, on the inner surface of the lid 8, with the axis 1 as the center, the top plate 3
A circular groove 8a having a diameter slightly smaller than the outer diameter is formed.
An O-ring 12 for pressing the top plate 3 is inserted into the circular groove 8a. Therefore, the lid 8 and the O-ring 12 fix the top plate 3 to the positioning portion (inner flange 7c).
It corresponds to the pressure contact means for pressure contact with. At the center of the lid 8, a viewing hole 8b for observing air bubbles in the closed container A from outside is formed. (Cover) The cover 9 is also formed by cutting aluminum into a bottomed cylindrical shape having an inner diameter equal to the outer diameter of each support column 7a. The cover 9 prevents the closed container A from being damaged by an entering matter from the outside and prevents dust such as dust from entering the inclination sensor. Notches 9a, 9a are provided at two locations on the edge of the cover 9 for connecting lead wires C electrically connected to the electrodes 4, 5, 6 to the outside and connecting to a tilt detection circuit (not shown).
Is formed. <Assembly procedure of the tilt sensor> To assemble the tilt sensor, first, the lead glass disk is polished to form the top plate 3 and the bottom plate 1 having the above-described shapes, and the lead glass tube is polished to the above-described shape. The cylindrical member 2 is prepared. Further, the holder 7, the lid 8 and the cover 9 having the above-described shapes are cut out from the aluminum block.

Next, the upper electrodes 4 and 5 are formed on the spherical concave surface 3a of the top plate 3 and the lower electrode 6 is formed on the upper surface 1a of the bottom plate 1 by the method described above. Next, the upper surface 1a of the bottom plate 1 and the lower end surface of the cylindrical member 2 are coaxially aligned and liquid-tightly bonded by an adhesive agent made of glass paste.
Then, the electrolytic solution L is injected into the concave portion of the container body thus configured so that the liquid surface is slightly lower than the edge thereof. The spherical concave surface 3a of the top plate 3 and the upper end surface of the cylindrical member 2 are made liquid-tight with an adhesive made of glass paste so that the outer peripheral surface of the top plate 3 and the outer peripheral surface of the cylindrical member 2 are coaxial. Glue to. And each electrode 4,
One end of the lead wire C is fixed to 5 and 6 by soldering. Thus, the closed container A is completed.

In the closed container A, air remaining in the container body forms bubbles B due to the surface tension between the spherical concave surface 3a and the electrolytic solution L. At this time, the deepest part of the spherical concave surface 3a (the center of the spherical concave surface 3a) is located on the extension line of the central axis of the cylindrical member 2, and when the cylindrical member 2 is erected along the vertical direction, the deepest part of the spherical concave surface 3a. The position of the part is the highest position inside the closed container A.

Next, the closed container A is dropped between the support pillars 7a formed on the upper surface of the holder 7. Then, the top plate 3 of the closed container A is restrained from moving in the radial direction by the inner surface of the support column portion 7a, and positioned in the axial direction by the flange surface of the inner flange 7c, so that the top plate 3 is stably held. To be done. That is, the positioning of the entire closed container A is performed with the flange surface of the inner flange 7c and the spherical concave surface 3a.
It is made only by contact with the peripheral portion of the. That is, in this state, the cylindrical member 2 and the bottom plate 1 are suspended in the space inside the holder 7 and are separated from the recess 7 d of the holder 7. Therefore, since the points at the peripheral edge of the spherical concave surface 3a and the deepest portion are equidistant, when the axis l of the holder 7 is set up along the vertical direction, the inner flange 7c and the spherical concave surface 3a.
The axis of the closed container A, which is positioned by contact with a, also faces in the vertical direction, and the deepest portion (center point) of the spherical concave surface 3a becomes the highest position on the inner surface of the closed container A. Therefore, the bubble B moves to the deepest part (center point) of the spherical concave surface 3a.

Next, the closed container A is rotated so that the direction in which the upper electrodes 4 and 5 are arranged is adjusted to the direction in which the inclination is desired to be detected. That is, in the plane of FIG. 1, the rotation position of the closed container A is adjusted so that the upper electrodes 4 and 5 are arranged in the left-right direction on the paper surface.

Next, the O-ring 12 is fitted in the circular groove 8a of the lid 8 and the lid 8 is put on the holder 7. Then, each counterbore 8c of the lid 8 is matched with each female screw hole 7b, and three countersunk screws 13 are screwed into each female screw hole 7b via the counterbore 8c.
When the flat head screws 13 are screwed in as much as possible, the O-ring 12 is deformed and comes into contact with the top surface of the top board 3 over the entire circumference regardless of the inclination of the top surface of the top board 3, and the top board 3 is deformed.
The top plate 3 is attached to the inner flange 7 of the holder 7 all around the
Press on c. Therefore, the sealed container A is fixed to the holder 7 while being positioned at the above-described position.

The tilt sensor is assembled by the above procedure. <Operation of Tilt Sensor> Next, the operation of the tilt sensor when the tilt sensor thus assembled measures the tilt angle of the tilt measurement target will be described.

First, in preparation for measurement, the tilt sensor is fixed to the tilt measurement target. In the above-described example, the rotation position of the sealed container A of the inclination sensor is adjusted so as to measure the inclination in the direction along the surface of the attachment portion 10. Therefore, when the tilt measurement target is a box-shaped object, the mounting portion 1 of this tilt sensor is placed on the surface along the direction in which the tilt is measured.
0 is fixed by the fixing screw 11. This fixing screw 11
Since the inner diameters of the fixing holes 10a, 10a of the attachment portion 10 through which the is inserted are larger than the outer diameter of the shaft portion of the fixing screw 11, the tilt sensor is slightly rotated in the plane of the attachment portion 10. The horizontal plane of the measurement object and the horizontal plane of the tilt sensor (the plane orthogonal to the axis 1) can be matched with each other. This operation is performed while observing the bubble B in the closed container A through the peep hole 8b of the lid 8 so that the bubble B moves to the center of the closed container A. After making such adjustments, from the top of the lid 8,
The cover 9 is put on the holder 7. At this time, each lead wire C is drawn out from the notch 9a provided in the cover 9, and the other end is connected to a tilt detection circuit (not shown).

When the inclination sensor is fixed in this manner, the inclination detecting circuit (not shown) causes the upper electrodes 4 and 5 to be released.
A voltage is applied between the lower electrode 6 and the lower electrode 6. Then, the resistance value between each upper electrode 4, 5 and the lower electrode 6 changes according to the contact area between each upper electrode 4, 5 and the electrolytic solution L. This resistance value is detected by a tilt detection circuit (not shown) and converted into a value indicating a tilt angle.

When the object to be measured is kept horizontal and the bubble B is located in the center of the closed container A, the resistance values generated between the upper electrodes 4, 5 and the lower electrode 6 are the same. A tilt detection circuit (not shown) detects tilt angle = 0. On the other hand, when the measurement target is tilted in either direction, the position of the bubble B is also displaced to either side of the upper electrode 4 or 5 accordingly. Then, a difference occurs in the resistance value generated between the upper electrodes 4 and 5 and the lower electrode 6, and a value indicating the tilt angle of the measurement target is output in the tilt angle detection device (not shown).

[0046]

Second Embodiment A tilt sensor according to a second embodiment of the present invention is different from the above-described first embodiment in that a spherical concave surface 23b is formed only in a central portion of a lower surface 23a of a top plate 23 of a closed container B. It is characterized by

FIG. 5 is a vertical sectional view showing the structure of the inclination sensor according to the second embodiment. The tilt sensor of the present embodiment is different from that of the first embodiment in that the closed container D, the holder 27 that holds the closed container D therein, and the holder 27 is closed and the closed container D is pressed against the holder 27. It is composed of a lid 28 for making it. Details of these components will be described below. (Airtight Container) The airtight container D of the present embodiment, like the airtight container A of the first embodiment, includes a cylindrical member 22, and a top plate 23 and a bottom plate 21 adhered to the upper and lower ends of the cylindrical member 22. It is configured. These cylindrical member 22, top plate 23,
The bottom plate 21 and the bottom plate 21 are both made of an insulating material such as lead glass, and are liquid-tightly bonded to each other with an adhesive such as glass paste.

The top plate 23 is made of a disk-shaped parallel flat glass and has an outer diameter of 21 [mm]. At the center of the lower surface 23a of the top plate 23, a spherical concave surface (a surface that gradually becomes deeper from the periphery toward the center) 23b that is an inner surface of the closed container B is formed coaxially with the lower surface 23a. Therefore, the deepest part of the spherical concave surface 23b comes to coincide with the center of the lower surface 23a of the top plate 23. The diameter of the edge of the spherical concave surface 23b is the same as the inner diameter of the tubular member 22 and is 13 [mm].

The spherical concave surface 23a of the top plate 23 is, for example, # 1.
It has been finished to a rough surface having an appropriate roughness with 000 abrasives. As shown in FIG. 6, a first upper electrode 24 and a second upper electrode 25 made of a platinum thin film are formed on the spherical concave surface 23a. These upper electrodes 24, 25
Is substantially the same as each of the upper electrodes 4 and 5 of the first embodiment, but the outer diameter of the outer peripheral edge thereof is slightly smaller than the diameter of the edge of the spherical concave surface 23a. In addition, the protrusions 24a provided on a part of the outer edges of the upper electrodes 24, 25,
25a extends from inside the spherical concave surface 23b toward the flat surface portion of the peripheral edge. That is, in the assembled state of the tilt sensor, the protrusions 24a and 25a are extended to a position where they are exposed to the outside of the cylindrical member 22 but do not contact the holder 27.
It has been formed. That is, each protrusion 24a, 25
The outer diameter of a is larger than the outer diameter of the cylindrical member 22, but smaller than the inner diameter of the holder 27. The method of forming these upper electrodes 24 and 25 is the same as that of the first embodiment.

The bottom plate 21 is a disk-shaped parallel flat glass and has an outer diameter of 19 [mm]. This bottom plate 2
The configuration of 1 is exactly the same as that of the first embodiment. The cylindrical member 22 is composed of a glass tube having a uniform thickness, its outer diameter is 15 [mm], and its inner diameter is 13 mm.
[Mm] is set. The upper and lower ends thereof are cut along a plane orthogonal to the central axis, and are coaxially joined to the lower surface 23a of the top plate 23 or the upper surface 21a of the bottom plate 21, respectively. In the second embodiment, the cylindrical member 2
Since the upper end surface of 2 is in close contact with the flat surface portion of the lower surface 23a of the top plate 23, it is formed as a surface orthogonal to the axis of the cylindrical member 22 like the lower end surface thereof. The cylindrical member 22
Together with the bottom plate 21 constitute a container body having a recess (a space formed by the inner peripheral surface of the cylindrical member 22 and the upper surface 21a of the bottom plate 21).

As in the case of the first embodiment, the electrolytic solution L is hermetically sealed in the airtight container D constructed in this manner, leaving the amount of air forming the bubbles B. As long as the deepest part of the spherical concave surface 23c of the top plate 23 is located at the highest position in the gravity direction, the bubble B is located at the center of the spherical concave surface 23c even if the processing accuracy of other portions is insufficient. become. (Holder) The holder 27 is formed into a bottomed cylindrical shape by cutting aluminum. The inner diameter of the recess 27d formed in the center of the holder 27 has two steps. That is, the innermost part thereof is a small-diameter portion having an inner diameter that is smaller than the top plate 23 but larger than the bottom plate 21, and a portion near the opening end is slightly larger than the top plate 23. It is a large diameter part having an inner diameter of the diameter. The step formed between the small-diameter portion and the large-diameter portion serves as a flange portion 27c for positioning the top plate 23. The distance between the flange portion 27c and the bottom surface of the recess 27d is longer than the length between the lower surface 23a of the top plate 23 and the lower surface 21b of the bottom plate 21 in the closed container D. Therefore, the flange portion 27c is a positioning portion that abuts the lower surface 23a of the top plate 23 and stably holds the top plate 23. Further, the holder 27 having this flange portion 27c
Has a function of passing the container body of the closed container D and preventing the top plate 23 from passing while the container body is passed and stably holding the surface of the top plate 23 on which the spherical concave surface 23b is formed. You will have.

Female screw holes are formed at a plurality of positions on the open end surface of the holder 27. (Lid) The lid 28 is also formed by cutting aluminum into a disk shape having the same outer diameter as the holder 27. The lid 28 is formed with a spot facing, into which the screw head of the flat head screw 33 screwed into the female screw hole is inserted, at a position corresponding to each female screw hole when the lid 28 is placed on the open end surface of the holder 27. Further, on the inner surface of the lid 28 (the surface in contact with the holder 27), a cylindrical protrusion 28a having a diameter slightly smaller than the outer diameter of the top plate 23 is formed coaxially with the lid 28. An O-ring 32 for press-contacting the top plate 23 is fitted on the outer periphery of the protruding portion 28a. <Assembly Procedure of Inclination Sensor> In order to assemble the inclination sensor, first, the lead glass disk is polished to form the top plate 23 and the bottom plate 21 having the above-described shapes, and the lead glass tube is polished to have the above-described shape. The cylindrical member 22 is prepared. Further, the holder 27 and the lid 28 having the above-described shapes are cut out from the aluminum block.

Next, the closed container D is assembled according to the same procedure as in the first embodiment. Then, the assembled closed container D is inserted into the recess 27d of the holder 27. Then
The top plate 23 of the closed container D is restricted from moving in the longitudinal direction by the inner surface of the large diameter portion of the recess 27d, and is positioned in the axial direction by the flange portion 27c. That is, positioning of the entire closed container D is performed by the flange portion 2
7c and the flat surface portion of the lower surface 23a of the top plate 23 only come into contact with each other. That is, in this state, the cylindrical member 2
2 and the bottom plate 21 are suspended in the recess 27a and are separated from the inner surface of the recess 27a. Therefore, when the shaft of the holder 27 is erected along the vertical direction, the flange portion 2
7c and the lower surface 23a of the top plate 23 are positioned so that the axis of the closed container D is also oriented in the vertical direction, and the spherical concave surface 23
The deepest part (center point) of b is the highest position on the inner surface of the closed container D. Therefore, the bubble B moves to the deepest part (center point) of the spherical concave surface 23b.

Next, the closed container D is rotated to adjust the direction in which the upper electrodes 24 and 25 are arranged side by side to the direction in which the inclination is desired to be detected. Next, the O-ring 32 is fitted into the protruding portion 28 a of the lid 28, and the lid 28 is put on the holder 27. Then, the counterbore of the lid 28 is matched with the female screw hole of the holder 27, and the flat head screw 33 is screwed in. When the flat head screw 33 is screwed in as much as possible, the O-ring 32 is deformed and comes into contact with the top surface of the top board 23 over the entire circumference regardless of the inclination of the top surface of the top board 23. The top plate 23 is pressed against the flange portion 27c of the holder 27 over the entire circumference thereof. Therefore, the closed container D is fixed to the holder 27 in the state of being positioned at the above-mentioned position.

The inclination sensor is assembled by the above procedure. <Operation of Tilt Sensor> Next, the operation of the tilt sensor when measuring the tilt angle of the tilt measurement target by the tilt sensor thus assembled is exactly the same as that of the first embodiment, and therefore the description thereof is omitted. To do.

[0056]

Third Embodiment Next, a third embodiment of the present invention will be described. The third embodiment differs from the first embodiment only in the shape of the upper electrode formed on the spherical concave surface 3a of the top plate 3. That is, the tilt sensor of the first embodiment is
Only the inclination in the paper surface direction of FIG. 1 is detected, and the inclination in the paper surface direction of FIG. 2 cannot be detected. Therefore, the shapes of the upper electrodes 4 and 5 are as shown in FIG.
As shown in FIG. 3, the two upper electrodes 4 and 5 were simply arranged in the x direction (the direction of the paper surface of FIG. 1).

On the other hand, in the third embodiment, the inclination can be detected not only in the paper surface direction of FIG. 1 but also in the paper surface direction of FIG. FIG. 7 is a view of the top plate 3 forming the tilt sensor according to the third embodiment as viewed from the spherical concave surface 3a side. In FIG. 7, the upper electrodes 41 to 44 formed on the spherical concave surface 3a are formed in a substantially circular shape that is coaxial with the spherical concave surface 3a, and the x-axis direction (paper surface direction in FIG. 1) and the y-axis direction (paper surface direction in FIG. 2). ), Four independent upper electrodes 41 to
44. Therefore, the combined resistance of the resistance of the first upper electrode 41 and the resistance of the second upper electrode 42 and the resistance of the third upper electrode 43 and the fourth upper electrode 4 are combined.
The difference between the combined resistance of the No. 4 and the combined resistance of the first upper electrode 41 and the combined resistance of the third upper electrode 43, the combined resistance of the second upper electrode 42, and the combined resistance of the second upper electrode 42. 4 The difference between the resistance of the upper electrode 44 and the combined resistance indicates the inclination in the y-axis direction.

The rest of the configuration and operation of the third embodiment are the same as those of the first embodiment, so a description thereof will be omitted.

[0059]

According to the tilt sensor of the present invention constructed as described above, the tilt sensor is composed of the container body having the concave portion and the top plate having the curved surface which gradually becomes deeper from the periphery closing the concave portion toward the center. Even when using a closed container in which a liquid that forms bubbles is enclosed as a bubble tube, regardless of the processing accuracy of the lower surface of the container body or the upper surface of the top plate, the spherical concave surface of the top plate It can be positioned at a predetermined position with respect to the holder.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a tilt sensor according to a first embodiment of the present invention, taken along line II in FIG. 3;

FIG. 2 is a longitudinal sectional view of the tilt sensor according to the first embodiment of the present invention, taken along line II-II in FIG. 3;

FIG. 3 is a top view of the tilt sensor of FIG. 1;

FIG. 4 is a plan view showing a spherical concave surface of the top plate of FIG.

FIG. 5 is a vertical sectional view of a tilt sensor according to a second embodiment of the present invention.

FIG. 6 is a plan view showing the lower surface of the top plate of FIG.

FIG. 7 is a plan view showing a spherical concave surface of a top plate used in a tilt sensor according to a third embodiment of the present invention.

FIG. 8 is a view showing a conventional bubble tube fixing mechanism.

FIG. 9 is a vertical sectional view showing the structure of the closed container.

[Explanation of symbols]

 1 Bottom plate 2 Cylindrical member 3 Top plate 3a Spherical concave surface 7 Holder 7c Inner flange 8 Lid 21 Bottom plate 22 Cylindrical member 23 Top plate 23a Lower surface 23b Spherical concave surface 27 Holder 27c Flange portion 28 Lid

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuko Ochiai 2-36-9 Maenocho, Itabashi-ku, Tokyo Asahi Optical Co., Ltd.

Claims (15)

[Claims] 1. A container main body having a concave portion, and a top plate having a curved surface that gradually becomes deeper from the periphery of closing the concave portion toward the center and having an outer diameter larger than the outer diameter of the container main body. Together with a hermetically sealed container in which a liquid that forms bubbles is sealed, a surface of the top plate on which the curved surface of the top plate is formed while the container body of the hermetically sealed container is passed through An inclination sensor, comprising: a holder that stably holds a surface on which the curved surface is formed by blocking passage. 2. A container main body having a concave portion, and a larger diameter than an outer diameter of an end portion of the container main body which has a curved surface that gradually becomes deeper from the periphery to close the concave portion toward the center. A top plate having an outer diameter of, and a sealed container in which a liquid that forms bubbles is enclosed, and a top plate that holds the top plate in stable contact with the surface of the top plate on which the curved surface is formed. And a holder having a positioning portion for controlling the inclination sensor. 3. The top plate has a circular flat surface, and the positioning portion abuts the surface of the top plate on which the curved surface is formed at at least three positions in the circumferential direction. The tilt sensor according to claim 2. 4. The tilt sensor according to claim 3, wherein the positioning portion is composed of a plurality of arc-shaped projections having a common center point. 5. The top plate has a circular flat surface, and the positioning portion is composed of an annular protrusion that abuts the surface of the top plate on which the curved surface is formed. The tilt sensor according to claim 2, wherein: 6. The positioning part is a flange formed on an inner peripheral surface of a concave part formed in the holder for holding the closed container therein. Tilt sensor. 7. The container main body comprises a tubular member that comes into contact with the curved surface of the top plate at one end surface thereof, and a bottom plate that closes the other end surface of the tubular member. The inclination sensor according to any one of claims 1 to 6. 8. The tilt sensor according to claim 1, wherein the liquid is an electrolytic solution. 9. The tilt sensor according to claim 1, wherein the top plate and the container body are made of glass. 10. The tilt sensor according to claim 1, wherein the container body is separated from the holder. 11. The tilt sensor according to claim 1, further comprising a press-contact means for press-contacting the top plate with the positioning portion. 12. The top plate has a circular surface, and the curved surface is a spherical concave surface formed over the entire area of this surface. The tilt sensor described in. 13. The top plate has a circular surface, and the curved surface is a spherical concave surface formed only in a portion of the flat surface facing the concave portion of the container body. The tilt sensor according to any one of claims 1 to 11. 14. A container main body having a recess, and a top plate having a curved surface that gradually becomes deeper from the periphery of closing the recess toward the center and having an outer diameter larger than the outer diameter of the container main body. Together with a closed container in which a liquid that forms bubbles is sealed, a holder in which a recess for storing the closed container is formed, and a diameter smaller than the outer diameter of the top plate and smaller than the inner diameter of the container body. While having a large inner diameter, of the recess at a position where the distance from the bottom of the recess is longer than the distance from the surface of the top plate on which the curved surface is formed in the container body to the end of the container body. A tilt sensor, comprising: a flange formed on an inner peripheral surface. 15. The tilt sensor according to claim 8, wherein electrodes for detecting the position of the bubble as electric resistance of the electrolyte are formed on the curved surface and the bottom surface of the recess.