CN201110779Y - Pillar type polar distance-changing type capacitance weighing sensor - Google Patents

Abstract

The utility model belongs to a columnar capacitance weighing sensor with variable distance between electrodes for an electronic weighing system, which is composed of a bearing head, a movable column, a capacitor upper plate, a capacitor lower plate, a bearing spring, an outer barrel, a base and the like, and the capacitor upper plate, the capacitor lower plate and the bearing spring are sealed in the outer barrel. The gravity of heavy objects acts on the bearing head, which presses the bearing spring downwards via the movable cylinder, the compressive deformation of the bearing spring enables the distance between the capacitor upper plate and the capacitor lower plate to be shorter, and the capacitance value between the capacitor upper plate and the capacitor lower plate is enlarged. The capacitance value between the capacitor upper plate and the capacitor lower plate can be detected by extra capacitance measurement circuits, and then the weight of the heavy objects can be obtained indirectly. The measurement range of the weighing sensor is much larger than the resistance strain sensor which is utilized widely at present, besides, the capacitance sensor has the advantages that the capacitance sensor can bear large temperature change with high sensibility, short dynamic response time, low mechanical loss and the like.

Description

Column type polar distance variable capacitance weighing sensor

One, technical field

The utility model relates to a kind of capacitance type sensor that is used for electronic weighing system.

Two, background technology

At present, extensively adopt resistance strain weighing transducer in the electronic weighing system, because the restriction of the strained limit, the relative variation of the metal strain silk resistance of this resistance sensor generally is lower than 1%, and the resistance of strain silk is subjected to Temperature Influence very big.By comparison, the relative variation of capacitance type sensor capacitance can be greater than 100%, so measurement range is much bigger; Capacitive transducer is generally made electrode with metal, makes insulation supporter with inorganic material, therefore can bear very big temperature variation.Capacitance type sensor also has advantages such as highly sensitive, that dynamic response time is short, mechanical loss is little in addition.

It is that the capacitance of measurand is often very little that capacitive transducer is still used less main cause so far, and stray capacitance (connecting the lead capacitance of capacitor plate and the leakage capacitance of sensor itself) is relative very big.The existence of stray capacitance has not only reduced measurement sensitivity, and causes non-linear output, even makes sensor be in unsettled duty.In recent years, because material, technology have particularly reached quite high level at aspects such as metering circuit and semiconductor technologies, so the influence of stray capacitance obtained solving preferably, makes the application of capacitive transducer be able to very fast development.

Three, summary of the invention

The purpose of this utility model is: design a kind of column type polar distance variable capacitance weighing sensor that is applicable to electronic scale, to remedy the deficiency of resistance strain weighing transducer.

Implementation procedure of the present utility model is such: it mainly is made up of load-bearing head, mobile post, electric capacity top crown, electric capacity bottom crown, load bearing spring, urceolus, base, bottom crown seat, mobile post upper end connects the load-bearing head, electric capacity top crown, electric capacity bottom crown and load bearing spring sealing are installed in the urceolus, the electric capacity top crown is fixed on the lower end of mobile post, and the electric capacity bottom crown is fixed on the upper end of bottom crown seat.The action of gravity of weight is on the load-bearing head, and by the downward pressing spring of mobile post, the compression deformation of spring makes the distance between the upper and lower pole plate of electric capacity diminish, and it is big that the capacitance between the upper and lower pole plate of electric capacity also just becomes.Capacitance by between the upper and lower pole plate of capacitance measurement circuit (prior art) detection electric capacity that adds just can obtain the weight of heavy value indirectly.

Advantage of the present utility model and compared with prior art its good effect be: measurement range is big, can bear very big temperature variation, also have advantages such as highly sensitive, that dynamic response time is short, mechanical loss is little in addition, can be widely used in the multiple electronic weighing system.

Four, description of drawings

Accompanying drawing is a structural representation of the present utility model.

Five, embodiment

Now in conjunction with the accompanying drawings embodiment of the present utility model is described in detail:

The utility model mainly is made up of load-bearing 1, mobile post 4, electric capacity top crown 5, electric capacity bottom crown 6, load bearing spring 7, urceolus 8, base 9, bottom crown seat 12.For screw threads for fastening is connected, be that feather key connects between the last hole of mobile post 4 and urceolus 8 between mobile post 4 upper ends and the load-bearing 1, electric capacity top crown 5 is pasted in the lower end; Electric capacity bottom crown 6 is fixed on the bottom crown seat 12; Load bearing spring 7 is contained between mobile post 4 and the base 9; Electric capacity top crown 5, electric capacity bottom crown 6, load bearing spring 7 sealings are installed in the urceolus 8.Screw 2 screws in the threaded hole of urceolus 8 upper ends, withstands mobile post 4, and is fastening by screw 3; Form feather key between the hole at bottom crown seat 12 and base 9 middle parts and connect, electric capacity bottom crown 6 is pasted in the upper end; The lead-in wire of electric capacity top crown 5 upwards passes from fairlead 19 through fairlead 18, and the lead-in wire of electric capacity bottom crown 6 passes from lead-in wire groove 16 through fairlead 17 downwards; Electric capacity top crown 5 and electric capacity bottom crown 6 are all made of the single face copper clad plate, and two deposited copper faces are relative; Screw 14 passes the internal thread hole that backing plate 15 screws in bottom crown seat 12, with nut 13 lockings; Be provided with spring eye on base 9, little spring 11 is packed in the hole of base 9, and the upper end contacts and support bottom crown seat 12 with bottom crown seat 12; Pack in the hole of urceolus 8 in base 9 upper ends, fastening with screw 10.

Principle of work of the present utility model is:

The action of gravity of weight is in load-bearing 1, and to pressing down load bearing spring 7, the compression deformation of load bearing spring makes the distance between electric capacity top crown 5 and the electric capacity bottom crown 6 diminish by mobile post 4, and it is big that the capacitance between the capacitor plate also just becomes.Capacitance by between the upper and lower pole plate of capacitance measurement circuit detection electric capacity that adds just can obtain the weight of heavy value indirectly.

The position of set screw 2, the height in the time of can changing load bearing spring initialization load, it is fastening with screw 3 to mix up the back.

The position of set screw 14 can change the height of electric capacity bottom crown 6, the capacitance of capacitive transducer when adjusting load bearing spring initialization load.Mixing up the back locks with nut 13.

Be that feather key connects between the hole on mobile post 4 and the urceolus 8 between the hole, on bottom crown seat 12 and the base 9, its effect is guiding and prevents that the upper and lower pole plate spaced winding of capacitive transducer when work electric capacity sensor axis from relatively rotating, thereby can avoid to avoid the upper and lower pole plate lead-in wire of electric capacity to be broken because of the upper and lower pole plate of electric capacity relatively rotates the influence to capacitance of the right alignment that produces, parallelism error around axis.

Claims (3)

1, column type polar distance variable capacitance weighing sensor, it is characterized in that: it mainly is made up of load-bearing head (1), mobile post (4), electric capacity top crown (5), electric capacity bottom crown (6), load bearing spring (7), urceolus (8), base (9), bottom crown seat (12), mobile post (4) upper end connects load-bearing head (1), electric capacity top crown (5) is fixed on the lower end of mobile post (4), electric capacity bottom crown (6) is fixed on the upper end of bottom crown seat (12), and electric capacity top crown (5), electric capacity bottom crown (6) and load bearing spring (7) sealing are installed in the urceolus (8).

2, column type polar distance variable capacitance weighing sensor according to claim 1 is characterized in that: the lead-in wire of electric capacity top crown (5) upwards passes from fairlead (19) by fairlead (18); The lead-in wire of electric capacity bottom crown (6) passes from lead-in wire groove (16) by fairlead (17) downwards.

3, column type polar distance variable capacitance weighing sensor according to claim 1 is characterized in that: going up design at base (9) has the hole of placing spring, and little spring (11) is placed in the hole, and the upper end contacts with bottom crown seat (12).

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