JP6942580B2 - Weighing device - Google Patents

Description

The present invention relates to a weighing device, and more particularly to an electronic balance that uses a secondary battery as one of the power sources.

The weighing device that measures the mass detects the variation of the beam caused by the load of the object to be measured placed on the weighing pan by the voltage due to the difference in the measuring mechanism, cancels this variation, and the amount of electricity for balancing the beam. Electromagnetic equilibrium type that measures the mass from, load cell type that measures the mass from the amount of electricity output by the variation of the strain gauge attached to the strain generator, the change in load is changed to the change in the gap of the electrode plate of the capacitor and the electron It is classified into a capacitance type that measures as a signal.

In these measuring devices, it is known that the measured value changes under the influence of the temperature change around the device or the device itself, which hinders accurate measurement. This is due to slight deformation caused by the difference in the coefficient of linear expansion due to the temperature of the parts constituting the measuring mechanism. Further, particularly in the case of the electromagnetic equilibrium type including a magnet, it is also caused by the temperature characteristics of the material constituting the magnet.

Therefore, it has been proposed that the electronic balance disclosed in Patent Document 1 is provided with a temperature sensor, and the load data is corrected based on the temperature data measured by the temperature sensor.

On the other hand, in the field of secondary batteries, it is known that there is a correlation as shown in FIG. 4 between the temperature of the battery and the discharge capacity. The remaining battery level is displayed as the ratio of the remaining battery level at the reference temperature corresponding to the measured voltage value by referring to the correlation between the voltage value at a predetermined reference temperature (for example, 0 degree) and the remaining battery level.

However, for example, when the reference temperature is 0 ° C., even if the remaining amount is displayed at 50%, when the battery temperature is 20 ° C., the actual remaining amount is less than 25%, and accurate display cannot be performed. As a result, there is a problem that the power is turned off much earlier than the user is aware of. Therefore, in an electronic device using a secondary battery unit as a power source, as in Patent Document 2, a temperature sensor is provided in the battery in order to display an accurate remaining amount even if the temperature changes, and measurement is performed by the temperature sensor. It has been proposed to correct the remaining battery level based on the generated temperature data and accurately display the remaining battery level.

Under such circumstances, there has been a demand for the development of a measuring device using a secondary battery as a power source, which can correct the temperature of the measured value and can correct the remaining battery level.

Japanese Unexamined Patent Publication No. 2000-0393356 Japanese Unexamined Patent Publication No. 2009-128128

However, when a temperature-correctable weighing device uses a secondary battery as a power source and attempts to accurately display the remaining battery level, the temperature sensor and its peripheral circuits are used for weighing value correction and battery level compensation. It is necessary to use two of them. As a result, there is a problem that the configuration becomes complicated, the cost increases due to the increase in the number of parts, and the device is upsizing.

The present invention has been made in view of the above circumstances, and provides a measuring device capable of accurately performing temperature correction of a measured value and temperature correction of a remaining battery level without increasing the number of temperature sensors. With the goal.

In order to achieve the above object, the measuring device of one embodiment according to the present invention includes a mass detection unit that detects the mass of the object to be measured, a temperature detection unit that detects the temperature of the mass detection unit, and the temperature detection unit. An arithmetic processing unit that generates measurement data by correcting the load data obtained by the mass detection unit based on the temperature data obtained by the unit, and a built-in secondary battery used as one of the power supplies. The calculation processing unit corrects the remaining amount of the secondary battery based on the temperature data.

In the above aspect, it is also preferable that the mass detection unit and the secondary battery are thermally coupled.

Further, in the above aspect, it is also preferable that the thermal coupling is achieved via the metal plate.

Further, it is also preferable that the weighing device is an electromagnetic equilibrium type electronic balance having a magnet in the mass detection unit in the above aspect, and the temperature sensor of the temperature detection unit is attached to the magnet.

In addition, in this specification, thermal coupling means that two or more members are thermally affected in the same manner.

According to the above aspect, it is possible to provide a weighing device capable of accurately performing temperature correction of the measured value and temperature correction of the remaining battery level without increasing the number of temperature sensors. As a result, it is possible to prevent cost increase and device upsizing due to an increase in the number of parts.

It is external perspective view of the electronic balance which concerns on embodiment of this invention. It is a block diagram of the structure of the electronic balance which concerns on the same form. It is a figure seen from the bottom surface with the lower case of the electronic balance which concerns on the same form removed. It is a graph which shows the correlation between the temperature and the discharge characteristic of a conventionally known secondary battery.

Hereinafter, embodiments of the weighing device according to the present invention will be described with reference to the drawings. The "front" and "rear" directions shown in FIG. 3 indicate the directions when the electronic balance 1 is installed in a used state for convenience of explanation, and do not limit the invention.

FIG. 1 is an external perspective view of an electronic balance 1 which is an example of a weighing device according to an embodiment. The main body of the electronic balance 1 is formed by the device case 3 in appearance. The device case 3 is composed of a vertically fitted structure of an upper case 3a and a lower case 3b, and a measuring mechanism 10 is housed therein. On the upper surface of the upper case 3a, a measuring plate 4 for placing an object to be measured, which is connected to the measuring mechanism 10 via a plate shaft (not shown), is exposed.

FIG. 2 is a block diagram of the measuring mechanism 10 of the electronic balance 1. As shown in FIG. 2, the electronic balance 1 includes a mass detection unit 11, a temperature detection unit 12, an operation unit 13, a display unit 14, a storage unit 15, a secondary battery 16, and a voltage detection unit 18. , And the arithmetic processing unit 19.

As shown in FIG. 3 described later, the mass detection unit 11 mainly includes a reverbal mechanism 21 composed of a frame, upper and lower beams, and a floating frame, and an electromagnet that outputs a compensation current so as to correct a variation in the beam (shown in the figure). It is provided with an electromagnetic part 24 having a magnet 23 (permanent magnet) fixed in the yoke 22 and a built-in weight control board 27 equipped with a built-in weight 25 for measuring a measured value and a circuit for controlling the built-in weight 25. ..

The temperature detection unit 12 detects the temperature of the mass detection unit 11 by the temperature sensor 26 (FIG. 3), and outputs the detected temperature data to the arithmetic processing unit 19. As the temperature sensor 26, various temperature sensors 26 using a thermistor, a thermoelectric pair, or the like can be used, but using a transistor is advantageous in terms of price. In the case of a transistor, the temperature is detected as a voltage drop of the temperature sensor 26 and converted into the temperature by the arithmetic processing unit 19.

The operation unit 13 is a key switch for the user to turn on / off the power of the electronic balance 1 and perform various setting operations. In FIG. 1, it is arranged in front of the upper case 3a.

The display unit 14 is a display device such as a liquid crystal display, and is arranged in front of the upper case 3a (FIG. 1). The display unit 14 displays measurement data obtained by the arithmetic processing unit 19 described later, a battery level display, and other displays necessary for setting.

The operation unit 13 and the display unit 14 may be integrally configured to be provided as the touch panel type operation unit 13.

The storage unit 15 is, for example, a rewritable non-volatile memory such as a flash memory, and stores various data used in the arithmetic processing unit 19. For example, the storage unit 15 stores a mass value (reference mass value) or the like corresponding to the built-in weight 25 (FIG. 3). Further, the storage unit 15 stores data related to temperature characteristics used for correcting load data and correcting the remaining amount of the secondary battery 16.

The secondary battery 16 is a storage battery unit that is used as a power source for the electronic balance 1 and can be charged by an external power source 17, such as a nickel hydrogen battery or a lithium battery. Although the secondary battery 16 is used by being built in the electronic balance 1, the electronic balance 1 may be configured to use an AC power source as an external power source 17 in addition to the secondary battery 16.

The voltage detection unit 18 detects the voltage of the secondary battery 16 and outputs the detected voltage to the arithmetic processing unit 19.

The arithmetic processing unit 19 is a so-called CPU (Central Processing Unit). The arithmetic processing unit 19 calculates the temperature data based on the voltage value input from the temperature detection unit and the temperature characteristics of the temperature sensor 26 and the measuring mechanism 10 stored in the storage unit 15 in advance. Further, the arithmetic processing unit 19 corrects the load data input from the mass detection unit 11 based on the temperature data, generates measurement data, and outputs it so as to be displayed on the display unit 14 as a numerical value. Further, the arithmetic processing unit 19 corrects the voltage data of the secondary battery 16 input from the voltage detection unit 18 based on the temperature data, converts it into the remaining battery level, and outputs it so as to be displayed on the display unit. do.

Next, the arrangement of the mass detection unit 11, the temperature sensor 26, and the secondary battery 16 in the electronic balance 1 will be described. FIG. 3 is a view of the main body of the electronic balance 1 viewed from the bottom surface of the device case 3 with the lower case 3b removed.

A reverbal mechanism 21 is arranged in the central portion of the main body. The electromagnetic portion 24 is arranged behind the reverbal mechanism 21, and a built-in weight 25 is arranged on the side of the reverbal mechanism 21. A yoke 22 is attached to the bottom surface side of the electromagnetic portion 24 by screwing. The temperature sensor 26 is attached directly to the magnet 23 or indirectly via the yoke 22.

The reverbal mechanism 21, the solenoid portion 24, the built-in weight 25, and the built-in weight control board 27 are housed in a container-shaped metal case 28 that opens toward the bottom surface, and are screwed to the upper case 3a of the electronic balance 1 or the like. It is attached by the appropriate means of. The material of the metal case 28 is preferably a metal having a high thermal conductivity such as iron, and preferably aluminum.

The outer wall 28a of the metal case 28 is configured such that at least one side of each member is close to each of the reverbal mechanism 21, the electromagnetic part 24, the built-in weight 25, the built-in weight control board 27, etc. of the mass detection unit 11. ing. With this configuration, the temperature of each member is transmitted through the metal wall, and the temperature of the mass detection unit 11 can be made uniform.

Further, the magnet 23 has the greatest influence on the measured value of the temperature coefficient (about −300 ppm / ° C.) of the mechanical component of the mass detection unit 11. Therefore, the temperature of the magnet 23 can be typically treated as being close to the temperature of the entire mass detection unit 11. The material of the magnet 23 is not particularly limited, but samarium cobalt is preferable.

On the other hand, the secondary battery 16 is arranged so as to be close to the outer wall of the metal case 28. As a result, the temperature sensor 26 attached to the mass detection unit 11 and the secondary battery 16 are thermally coupled via the outer wall 28a of the metal case 28.

Since the heat capacity of the secondary battery 16 is similar to the heat capacity of the magnet 23, the secondary battery 16 and the magnet 23 behave thermally similar to temperature changes inside and outside the balance. When the secondary battery 16 and the mass detection unit 11 are thermally coupled as described above, the temperature detected by the temperature sensor 26 can be regarded as the temperature of the secondary battery 16.

According to the above configuration, the remaining amount of the secondary battery 16 is also corrected based on the temperature data obtained by the temperature detection unit 12 attached to the mass detection unit 11, thereby correcting the temperature of the measurement data with a simple configuration. And a weighing device capable of temperature compensation of the remaining battery level can be provided.

Further, when the mass detection unit 11 and the secondary battery 16 are arranged at a position where they are thermally coupled, the temperature detected by the temperature detection unit 12 and the temperature of the secondary battery 16 can be satisfactorily approximated. As a result, the remaining amount of the secondary battery 16 can be corrected more accurately by using the temperature data of the temperature detection unit 12.

Further, the mass detection unit 11 and the secondary battery 16 are thermally coupled by a simple structure of a metal plate (outer wall of the metal case) 28a. As described above, since the thermal bond is achieved by simply arranging the outer wall of the metal, that is, the metal plate so as to be close to each other, no special step is required for that purpose.

The temperature sensor 26 as illustrated above does not measure the absolute value of the temperature, but measures, for example, the resistance value and converts it as the temperature. Further, the temperature sensor 26 such as a transistor has individual characteristics. Therefore, as a pre-shipment operation of the electronic balance 1, the temperature characteristics of the mass detection unit 11 are obtained at a plurality of temperatures (for example, 10 ° C. and 30 ° C.), and the temperature characteristics are stored in the storage unit 15 as a table or the like and stored in the data. Based on this, it is set to correct the load data. When a separate temperature sensor is provided for correcting the remaining battery level of the secondary battery 16 in addition to the temperature sensor 26 arranged in the mass detection unit 11, the same operation is performed for the temperature sensor. According to the above aspect, the process can be simplified without the need to perform such additional work.

In the above embodiment, the electromagnetic equilibrium type electronic balance has been described as an example, but the present invention can be similarly applied to other measuring mechanisms such as a load cell type and a capacitance type.

1 Electronic balance (weighing device)
11 Mass detection unit 12 Temperature detection unit 19 Calculation processing unit 16 Secondary battery 23 Magnet 26 Temperature sensor 28a Outer wall (metal plate) of metal case

Claims (4)

A mass detector that detects the mass of the object to be measured,
A temperature detection unit that detects the temperature of the mass detection unit, and
An arithmetic processing unit that generates measurement data by correcting the load data obtained by the mass detection unit based on the temperature data obtained by the temperature detection unit.
Equipped with a built-in secondary battery used as one of the power sources
The arithmetic processing unit corrects the remaining amount of the secondary battery based on the temperature data .
The mass detection unit and the secondary battery are thermally coupled to each other.
A weighing device, characterized in that the thermal coupling is achieved via a metal plate . The metering device, an electromagnetic balance type electronic balance comprising a magnet on the mass detection unit,
The measuring device according to claim 1 , wherein the temperature sensor of the temperature detecting unit is attached to the magnet. The weighing device according to claim 1 or 2, wherein the material of the metal plate is aluminum. The mass detection unit is housed in a container-shaped metal case made of the metal plate.
The weighing device according to any one of claims 1 to 3, wherein the secondary battery is arranged so as to be close to the outer wall of the metal case .

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