JPH0933328A - Weight sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the interference of a noise signal or the like from the outside, and to allow no measurement error to occur even if an offset load is applied to an object to be measured mounted on a pan. SOLUTION: A sensor portion 3 which detects the change amount of capacitance between a moving electrode plate moving by the deflection of a beam 2 and a fixed electrode plate confronting to the moving electrode plate with a predetermined distance so as to output a weight detection signal, is provided, and a front side and a back side portions 30, 31 which cover the sensor portion 3 are provided on a support member 4 supported by the beam 2, and the support member 4 is equipped with a fitting face portion 28 fixed to the beam 2, and plural fitting seat portions 32, 33, 34, 35 which are successively provide on the fitting face portion 28 and are positioned on a virtual circle centering the center of the beam 2 and to which a cover is fitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a weight sensor device for detecting the weight of a heavy object, for example, an object to be measured such as a container containing a liquid raw material.

[0002]

2. Description of the Related Art A conventional weight sensor device of this type is shown in FIG.
As shown in FIG.
1. The lower mounting seat 72 of one end is fixed, the upper plate 74 is fixed to the upper mounting seat 73 of the other end of the flexure element 71, and the bracket 75 is attached to the lower mounting seat 72. Fixed electrode plate 7
The base of No. 6 is attached, and the base of the movable electrode plate 78 is attached to the end face of the flexure element (beam) 71 via the bracket 77 so that the fixed electrode plate 76 and the movable electrode plate 78 have a predetermined gap. It is a structure in which they face each other.

The object 79 to be measured is placed on the upper plate 74 and the weight thereof is measured. In this case, the upper plate 74 is pushed downward by the weight of the object 79 to be measured. The flexure element 71 is bent. The bending of the flexure element 71 moves the movable electrode plate 78, and changes the distance between the movable electrode plate 78 and the fixed electrode plate 76. For this reason, the electrostatic capacitance between the fixed electrode plate 76 and the movable electrode plate 78 changes, and the amount of change is detected and used as an output signal for weight detection.

[0004]

However, in the above-mentioned conventional weight sensor device, the sensor portion composed of the movable electrode plate 78 and the fixed electrode plate 76 is exposed, and any shield measure is taken. Since it does not exist, interference of noise signals from the outside occurs and hinders accurate weight measurement. Moreover, since the upper plate 74 is supported at only one place, it is placed on the upper plate 74. There is a problem that a measurement error occurs when an unbalanced load is applied by the object to be measured 79.

The present invention has been made in view of the above problems, and an object thereof is to shield the sensor portion to prevent interference of noise signals from the outside and to achieve accurate measurement. It is to provide a weight sensor device capable of detecting weight.

[0006]

In order to achieve the above object, a weight sensor device according to the invention of claim 1 is provided with a base and a free end which is fixed to the base at one end fixing side and the other end. A flexure element having a support member holding portion on the upper part of the portion,
The weight detection signal is detected by detecting the amount of change in capacitance between one electrode plate that moves due to the bending of the strain-generating body and the other electrode plate that faces the one electrode plate at a predetermined distance. The support includes: a sensor unit for outputting, a support member held by the support member holding unit of the flexure element, and a cover having a placement unit supported by the support member for placing an object to be measured. The member is provided with a sensor cover portion that covers the sensor portion.

Therefore, since the sensor section is covered and shielded by the sensor cover section provided on the support member, interference of noise signals from the outside is prevented and accurate weight detection is possible.

In order to achieve the above object, the weight sensor device according to a second aspect of the present invention is the weight sensor device according to the first aspect, wherein the support member holds the support member of the flexure element. And a plurality of mounting seat portions that are connected to the mounting surface portion and that are located on a virtual circle centered on the center of the flexure element and to which the cover is mounted.

Therefore, since the object to be measured placed on the cover can be received at multiple points and can be transmitted to the flexure element at one point on the mounting surface portion, a measurement error due to an unbalanced load can be reduced. can do.

In order to achieve the above object, the weight sensor device according to a third aspect of the present invention is the weight sensor device according to the first or second aspect, in which the free end portion of the flexure element is attached. A stopper mechanism was provided for restricting the displacement of the free end portion of the strain generating element when an excessive load was applied.

Therefore, it is possible to prevent the deformation of the flexure element itself due to an excessive load on the free end of the flexure element.

In order to achieve the above object, a weight sensor device according to a fourth aspect of the present invention is the weight sensor device according to the first aspect, the second aspect, or the third aspect, in which the peripheral portion of the base is A cushioning member is provided for cushioning and sealing with the peripheral portion of the cover.

Therefore, the cushioning member can provide cushioning and sealing between the peripheral portion of the base and the peripheral portion of the cover.

In order to achieve the above object, the weight sensor device according to the invention of claim 5 is the weight sensor device according to claim 1 or claim 2 or claim 3 or claim 4, wherein The lower surface of the strained body is provided with a recess and electrode mounting portions located on both sides of the recess, and a step is provided between one electrode mounting portion and the other electrode mounting portion to provide one electrode mounting portion. The base portion of one electrode plate was attached to the base plate, the base portion of the other electrode plate was attached to the other electrode attachment portion, and both electrode plates were opposed to each other with a predetermined gap.

Therefore, the one and the other electrode plates can be directly attached to the lower surface of the flexure element, and the bracket in the conventional weight sensor device becomes unnecessary.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. 1 (1) is a perspective view of a weight sensor device according to the present invention, FIG. 1 (2) is a sectional view of a cover of the same, and FIG. 2 is a vertical sectional view of the weight sensor device according to the present invention. is there.

As shown in FIGS. 1 and 2, the weight sensor according to the present invention includes a dish-shaped base 1 which is circular in plan view, a beam 2 which is a flexure element, and a capacitive sensor section 3. The support member 4 and the cover 5 which is circular in a plan view are provided.

The base 1 is a dish-shaped body having a peripheral wall portion 1b formed on the peripheral portion of the bottom surface portion 1a.
Is formed with a beam attachment portion 8 having an attachment hole 8a on the left side thereof, and a flange portion 6 is formed on an upper peripheral edge portion of the peripheral wall portion 1b. An end portion of the flange portion 6 is formed downward. A bent locking portion 6a is formed. In addition, the peripheral wall portion 1
A hole 7 is formed in b.

The beam 2 is provided with a beam main body 9 composed of a rectangular block, and a central portion of the beam main body 9 is formed with a hole-shaped portion 10 which is cut out to front and rear surface portions 9a and 9b of the beam main body 9. And the lower surface 9c of the beam body 9
The sensor mounting portion 11 is located at the central portion thereof, the mounting seat portion 12 is located on the left side, which is the fixing side, and the right end portion, which is the free end portion, is the stopper mechanism. The stopper portions 13 are formed respectively, and the upper surface portion 9d of the beam body 9 is formed with a mounting seat portion 14 which is a supporting member holding portion and is located on the right side thereof. The mounting seats 12, 14 are formed with screw holes 12A, 14A.

The sensor mounting portion 11 has a recess 15 formed in the lower surface 9c of the beam body 9 and the recess 15
The left and right electrode mounting portions 16 and 17 are formed by sandwiching the electrode mounting portions 16 and 17 on the left and right sides.
7, there is a step, and the left electrode mounting portion 16 is provided with a pair of groove portions 18 continuous with the recess 15 as shown in FIG.

The sensor mounting portion 11 has the sensor portion 3
Is installed. That is, the sensor unit 3 includes a movable electrode plate 20 which is one of rectangular electrode plates and a fixed electrode plate 19 which is the other electrode plate, and a pair of mounting members is attached to the base of the fixed electrode plate 19. Pieces 21 are formed, and these attachment pieces 21 are provided with attachment holes 22. A mounting hole 23 is provided at the base of the movable electrode plate 20.

The fixed electrode plate 19 is provided with a pair of mounting pieces 21 at the base thereof in the groove portion 1 of the left electrode mounting portion 16.
8 is inserted through an insulating spacer 24 and attached to the left electrode mounting portion 16 by a screw member (or caulking) 25. The movable electrode plate 20 has an insulating spacer 2 at its base portion.
It is attached to the right electrode attachment portion 17 by a screw member (or caulking) 27 via 6, and the fixed electrode plate 19 and the movable electrode plate 20 face each other with a predetermined gap t.

As shown in FIGS. 3 and 4, the support member 4 has a mounting surface portion 28 having a pair of screw holes 28a, and a right side edge portion of the mounting surface portion 28 which is bent and formed at a right angle to the mounting surface portion 28. The right side end surface portion 29 and the front and rear side surface portions 30, which are sensor cover portions formed by bending the front and rear edge portions of the mounting surface portion 28 at right angles to the mounting surface portion 28,
31 and the end surface portion 29 is extended in the front-rear direction, the front and rear extended end portions 29A, 29B are bent to the left, and the upper seat portion has a mounting seat portion 32, Three
3 are formed, and the mounting seat portions 32 and 33 are provided with screw holes 32a and 33a.

The front and rear side surfaces 30 and 31 are extended to the left, the extended end portions 30A and 31A are bent outward, and the mounting seat portion 34 is provided at the upper edge thereof. ,
35 are formed, and the mounting seat portions 34, 35 are provided with screw holes 34a, 35a. Further, board attachment pieces 36, 37, 38 project from the left edge of the attachment surface 28 and the upper edges of the front and rear side surfaces 30, 31. Then, the mounting seat portions 32, 33, 34, and 35 are dispersedly positioned on a virtual circle centered on the center of the beam 2.

The cover 5 has a mounting portion 40 on the surface thereof, and the mounting portion 40 comprises a positioning convex portion 41 and a tread surface portion 42. A plurality of fixing portions 43 are formed on the positioning convex portion 41 at predetermined intervals in the circumferential direction, and the fixing portions 43 are provided with screw through holes 44.

Then, the beam 2 is fixed to the beam mounting portion 8 of the bottom surface 1a of the base 1 by the mounting screw 45 at the mounting seat portion 12, and the mounting seat portion 14 is mounted on the beam 2. The support member 4 is attached to the portion of FIG. 2 by fixing the attachment surface portion 28 thereof with attachment screws 46. In this case, the stopper portion 13 of the beam 2 does not contact the bottom surface portion 1a of the base 1 and has a gap t1 between them. The right end surface of the beam 2 is covered by the right end surface portion 29 of the support member 4,
The front and rear side surfaces 9a and 9b are covered by the front and rear side surfaces 30 and 31 of the support member 4, and the front and rear of the sensor portion 3 provided at the lower portion of the beam 2 is in front of the support member 4. ,
Since the sensor part 3 is covered by the rear side parts 30 and 31 and the sensor part 3 is shielded, interference of noise signals from the outside is prevented.

Then, the board mounting piece 3 of the supporting member 4
A printed circuit board 47 is fixed to each of 6, 37 and 38 with a screw member 48, and the fixed electrode plate 19 and the movable electrode plate 20 of the sensor unit 3 are connected to the printed circuit board 47 via lead wires (not shown). An external lead wire 49 is connected to the printed circuit board 47. The external lead wire 49 penetrates the grommet 50 provided in the hole portion 7 of the peripheral wall portion 1b of the base 1. Outsourced.

The cover 5 is covered on the supporting member 4, and the mounting seat portions 32, 33, 34 and 35 are in contact with the fixing portion 43 of the cover 5 from below, and the fixing portion 43 Attach the mounting screw 53 that penetrates the screw through hole 44 to the screw holes 32a, 33a, 3 of the mounting seat portions 32, 33, 34, 35.
The support member 4 holds the cover 5 at multiple points by being screwed into 4a and 35a.

The peripheral edge of the flange 6 of the base 1 and the peripheral edge of the tread surface 42 of the cover 5 are covered with a seal member (seal rubber) 52 as a cushioning member, and the peripheral edge of the flange 6 is covered. The seal member 52 is locked to the locking portion.

Next, the operation of the weight sensor constructed as above will be described. In general, an object to be measured 60 such as a container containing a liquid raw material such as syrup has legs 61 on the bottom surface periphery as shown in (2) of FIG. And
The object to be measured 60 is placed on the installation portion 40 of the weight sensor and its weight is measured. In this case, the cover 5 is pushed downward by the weight of the object to be measured 60 and the support member 4 is pressed. The beam 2 is deflected via. The bending of the beam 2 moves the movable electrode plate 20 to change the distance (predetermined gap t) between the movable electrode plate 20 and the fixed electrode plate 19. For this purpose, the fixed electrode plate 19
The capacitance between the movable electrode plate 20 and the movable electrode plate 20 changes, and the amount of change is detected and used as an output signal for weight detection.

In the above-described embodiment, the front and rear side surface portions 9a and 9b of the beam 2 are covered by the front and rear side surface portions 30 and 31 which are the sensor covering portions of the support member 4, Since the front and rear of the sensor unit 3 provided at the lower portion of the beam 2 are covered by the front and rear side surfaces 30 and 31 of the support member 4, the sensor unit 3 is shielded and a noise signal from the outside is received. And the like are prevented.

Further, the mounting seat portions 32, 33, 34, 35 are in contact with the fixing portion 43 of the cover 5 from below, and the mounting screw 53 penetrating the screw through hole 44 of the fixing portion 43 is attached to the mounting seat portion 32. , 33, 34, 35 screw holes 32a, 33a,
The support member 4 holds the cover 5 by being screwed to 34 a and 35 a, receives the object to be measured placed on the cover 5 at multiple points, and the beam 2 has the mounting surface portion 28. Therefore, the measurement error can be reduced by the unbalanced load.

Further, by providing a stopper portion 13 as a stopper mechanism on the lower surface portion 9c of the free end portion of the beam body 9 of the beam 2, when an excessive load is applied to the free end portion of the beam 2, this beam 2 is deformed and the stopper portion 13 collides with the base 1 to prevent the beam 2 itself from being deformed.

The stopper mechanism is not limited to the stopper portion 13 described above, but as shown in FIG. 4, the lower edge portions of the extended end portions 29A and 29B of the end surface portion 29 of the support member 4 and the front and rear side surface portions. Extended end portions 30A, 31B of 30, 31
Stoppers 39 may be provided so as to protrude from the lower edges of the base 1 as shown in FIG.
A plurality of stopper bolt mounting screw holes 6A are provided at predetermined intervals in the flange portion 6 of the stopper bolt 51. And a rear surface of the tread portion 42 of the cover 5 may be provided with a gap t1.

A sealing member (seal rubber) 52, which is a cushioning member, is placed on the peripheral edge of the flange portion 6 of the base 1 and the peripheral edge portion of the tread surface portion 42 of the cover 5 to engage the peripheral edge portion of the flange portion 6. By locking the seal member 52 to the stopper 6a, the base member 1
It is possible to perform cushioning and sealing between the peripheral edge of the cover and the peripheral edge of the cover 5.

The cushioning member is not limited to the seal member 52, but may be formed between the peripheral portion of the flange portion 6 of the base 1 and the peripheral portion of the tread portion 42 of the cover 5 as shown in FIG. The ring 55 may be interposed.

A sensor mounting portion 11 is provided on the lower surface portion 9c of the beam 2 so as to be located at the central portion thereof, and the sensor mounting portion 11 serves as a recess 15 formed in the lower surface portion 9c of the beam body 9. The left and right electrode mounting portions 16 and 17 sandwiching the recess 15 are provided with a step between the left electrode mounting portion 16 and the right electrode mounting portion 17, and the fixed electrode The plate 19 is inserted into the groove portion 18 of the left electrode mounting portion 16 via the insulating spacer 24 with the pair of mounting piece portions 21 of the base portion thereof, and is mounted on the left electrode mounting portion 16 by the screw member 25. The plate 20 is attached to the right electrode attachment portion 17 by a screw member 27 at its base portion via an insulating spacer 26, and the fixed electrode plate 19 and the movable electrode plate 20 are opposed to each other with a predetermined gap t. The fixed electric And it can be attached to the lower surface of the plate 19 and the movable electrode plate 20 directly to the beam 2,
The bracket in the conventional weight sensor device becomes unnecessary.

The fixed electrode plate 19 is attached to the left electrode attaching portion 16 via the insulating spacer 24, and the movable electrode plate 20 is attached to the right electrode attaching portion 17 via the insulating spacer 26 at the base thereof. Attach the fixed electrode plate 19
While the movable electrode plate 20 is opposed to the upper side of the fixed electrode plate 19 with a predetermined gap t, the movable electrode plate 20 is opposed to the lower side of the fixed electrode plate 19 with a predetermined gap t as shown in FIG. May be.

In this case, the cover 5 is pushed downward by the weight of the object to be measured 60 and the beam 2 is bent through the support member 4, and the bending of the beam 2 is caused by the movable electrode plate 20.
Is moved away from the fixed electrode plate 19,
The distance (predetermined gap t) between the movable electrode plate 20 and the fixed electrode plate 19 is changed.

[0040]

As described above, in the weight sensor device according to the first aspect of the invention, the base and the base are fixed to the base at the fixing side at one end and above the free end at the other end. Capacitance between a flexure element having a support member holding portion, one electrode plate that moves due to bending of the flexure element, and the other electrode plate that faces the one electrode plate with a predetermined distance. A sensor unit that detects the amount of change in
A support member held by the support member holding portion of the flexure element, and a cover having a placement portion that is supported by the support member and places an object to be measured are provided, and the sensor portion is provided on the support member. By providing the sensor covering portion that covers the sensor portion, the sensor portion is covered and shielded by the sensor covering portion provided on the support member, so that interference of noise signals from the outside is prevented. Therefore, accurate weight detection is possible.

According to a second aspect of the present invention, there is provided the weight sensor device according to the first aspect, wherein the support member is fixed to the support member holding portion of the strain element. The surface portion and a plurality of mounting seat portions that are connected to the mounting surface portion and are located on a virtual circle centered on the center of the strain-flexing body and to which the cover is mounted are provided. Not only can the same effects as the effects of the invention be achieved, but the object to be measured placed on the cover is received at multiple points, and the strain element can be transmitted at one point on the mounting surface portion. Unbalanced load can reduce measurement error.

Further, in the weight sensor device according to the invention of claim 3, in the weight sensor device of claim 1 or 2, when an excessive load is applied to the free end portion of the strain element, By providing the stopper mechanism for restricting the displacement of the free end portion of the strain generating body, not only the same effect as the effect of the invention of the above-described claim 1 can be obtained, but also an excessive amount of the strain generating body to the free end portion is provided. It is possible to prevent the deformation of the flexure element itself due to the load.

Further, in the weight sensor device according to the invention of claim 4, in the weight sensor device according to claim 1, 2 or 3, the peripheral portion of the base and the peripheral portion of the cover are provided. By providing the cushioning member for cushioning and sealing between the two, not only the same effect as the effect of the invention of claim 1 described above can be obtained, but also the peripheral edge portion of the base and the peripheral edge portion of the cover are formed by the buffer member. Buffering and sealing between can be done.

According to a fifth aspect of the present invention, there is provided the weight sensor device according to the first aspect, the second aspect, the third aspect, or the fourth aspect, wherein the lower surface portion of the flexure element is provided. , A recess and electrode mounting portions located on both sides of the recess are provided, and a step is provided between one electrode mounting portion and the other electrode mounting portion, and one electrode mounting portion is provided with one electrode plate The base part is attached, the base part of the other electrode plate is attached to the other electrode mounting part, and the two electrode plates are opposed to each other with a predetermined gap therebetween.
Not only can the same effects as those of the invention described above be obtained, but one and the other electrode plates can be directly attached to the lower surface of the strain-flexing body, so that the bracket in the conventional weight sensor device becomes unnecessary.

[Brief description of drawings]

FIG. 1A is a perspective view of a weight sensor device according to the present invention. (2) is a cross-sectional view of the cover of the weight sensor device.

FIG. 2 is a vertical sectional view of a weight sensor device according to the present invention.

FIG. 3 is a plan view showing a state in which a support member is attached to a strain-generating body of the weight sensor device.

FIG. 4 is a perspective view of a support member of the weight sensor device.

FIG. 5 is a structural explanatory view of a stopper mechanism of the weight sensor device.

FIG. 6 is a plan view seen from the back side of the sensor unit of the weight sensor device.

FIG. 7 is a structural explanatory view of another cushioning mechanism of the weight sensor device.

FIG. 8 is a configuration explanatory diagram of another sensor unit of the weight sensor device.

FIG. 9 is a vertical cross-sectional view of a conventional weight sensor device.

[Explanation of symbols]

 1 Base 2 Beam (Strain Element) 3 Sensor 4 Support Member 5 Cover 19 Fixed Electrode Plate 20 Movable Electrode Plate 28 Mounting Surface 30 Front Side of Support Member (Sensor Cover) 31 Rear Side of Support (Sensor Cover) Part) 32, 33, 34, 35 mounting seat part

Claims (5)

[Claims] 1. A base, a strain-flexing body fixed to the base at a fixing side at one end and having a support member holding portion at an upper portion of a free end at the other end, and one of which is moved by bending of the strain-generating body. Of the electrode plate and the other electrode plate facing the one electrode plate at a predetermined distance and outputting a weight detection signal by detecting the amount of change in capacitance, A support member held by the support member holding portion, and a cover having a mounting portion that is supported by the support member and mounts an object to be measured, and the support member covers the sensor portion. A weight sensor device comprising: 2. The mounting member, wherein the supporting member is fixed to the supporting member holding portion of the strain-generating body, and a virtual circle centered on the center of the strain-generating body and connected to the mounting surface portion. The weight sensor device according to claim 1, further comprising a plurality of mounting seat portions that are located and to which the cover is mounted. 3. The weight sensor according to claim 1, further comprising a stopper mechanism for restricting displacement of the free end portion of the strain-generating body when an excessive load is applied to the free end portion of the strain-generating body. apparatus. 4. The weight sensor device according to claim 1, further comprising a cushioning member that cushions and seals between the peripheral portion of the base and the peripheral portion of the cover. 5. The lower surface of the flexure element is provided with a recess and electrode mounting portions located on both sides of the recess, and a step is formed between one electrode mounting portion and the other electrode mounting portion. And a base portion of one electrode plate is attached to one electrode attachment portion, and a base portion of the other electrode plate is attached to the other electrode attachment portion, and the two electrode plates are opposed to each other with a predetermined gap. The weight sensor device according to claim 1 or claim 2 or claim 3 or claim 4.