JP5981776B2 - Weighing device - Google Patents

Description

  The present invention relates to a weighing device, and for example, relates to a weighing device that measures an object to be weighed such as meat, fish, processed food, and pharmaceuticals while determining the quality of the object to be weighed based on a measured value.

  2. Description of the Related Art Conventionally, in a production line for foods and the like, a filling device that fills a product to be weighed, for example, so that the weight of an object to be weighed becomes a reference value, and a post-filling device that is provided after the filling device and is loaded from the filling device. A weighing device that measures the weight of the object to be weighed and determines the quality of the object to be weighed based on whether the measured value is within a preset lower limit value and upper limit value weight range. Yes.

  The filling amount control device of the filling device provided in such a production line is constituted by using a rough filling machine and a correction filling machine in order to fill an accurate filling amount, and the rough filling machine filled with the rough filling machine. Weighing the filling amount, feedback control of the coarse filling machine according to the trend, and the technology that feeds the correction filling machine with the shortage of the fixed value of the coarse filling amount, and the total weight after the correction filling A total weight measuring unit for sampling, a sampling circuit for sampling the measured value obtained from the total weight measuring unit, an average value calculating circuit for calculating an average value of values sampled by the sampling circuit, and an average value calculating circuit. A comparison operation circuit that compares and calculates the average value obtained and a target set center value, and feedforward control of the correction filling machine based on the ratio calculated by the comparison operation circuit Technology to control the is known (e.g., see Patent Document 1).

Japanese Unexamined Patent Publication No. 57-60222

  However, in the production line, even when there are many good products in which the filling amount of the object to be weighed is within the weight range of the lower limit value and the upper limit value, when the average value of the filling amount exceeds the reference value, There is a problem that the raw material is consumed wastefully for many articles, and the yield deteriorates.

  On the other hand, when reducing the filling amount in the filling device in order to improve the yield, if the reduction amount is too large, the weighing device falls below the lower limit value and the number of objects to be judged as defective products increases, resulting in a defective product rate. There was a fear that would rise.

  Thus, in order to improve the yield, it is effective to correct the reference value in the filling device so that the defective product rate does not increase. Therefore, the filling amount control device described in Patent Document 1 has a problem that it is impossible to grasp the optimum correction amount of the reference value.

  Therefore, the present invention has been made to solve the conventional problems as described above, and provides a weighing device that can support the improvement of the yield of the production line without increasing the defective product rate. It is aimed.

The weighing apparatus according to the present invention includes a conveying unit that conveys the object to be weighed that has been loaded from a filling device that performs filling so that the weight of the object to be weighed W composed of a plurality of articles becomes a predetermined reference value, and the conveyance Weighing means for weighing the object to be weighed conveyed to the means, and the weight to be weighed by the weighing means is within a range between a lower limit value and an upper limit value predetermined according to the reference value with determining the object as a non-defective, the metering device and a good determination means you determine the weight is outside the range between the upper limit and the lower limit the objects to be weighed as a defective product, the metering The average value, standard deviation, minimum value, and number of measured values of the plurality of objects weighed by the means are less than the lower limit value. Defect on the upper limit side of the object to be weighed exceeding the value The number, the statistical value calculating means for calculating a statistical value including, when the minimum value is greater than the lower limit, the difference obtained by subtracting the reference value from the average value is a positive value, and, from the minimum value When the difference obtained by subtracting the lower limit value is a positive value, a filling correction amount calculating means for calculating a difference obtained by subtracting the lower limit value from the minimum value as a correction amount in the decreasing direction of the reference value; and the filling correction amount Display means for displaying the correction amount calculated by the calculation means.

  With this configuration, the average value of the objects to be weighed by the weighing device approaches the reference value when the user decreases and changes the reference value of the filling device according to the correction amount displayed on the display means. Yield can be improved.

  Further, in the weighing device according to the present invention, when the minimum correction value is larger than the lower limit value, the filling correction amount calculation means is configured to calculate a difference between the average value and the reference value, and the minimum value and the lower limit value. Based on the difference, a margin in the decreasing direction of the reference value is calculated so as to be a correction amount so that the minimum value is equal to or greater than the lower limit value.

  With this configuration, the margin in the reduction direction of the reference value is calculated so that the minimum value is equal to or greater than the lower limit value, so that the defective product rate increases even if the reference value of the filling device is changed in the reduction direction. There is no. Therefore, the yield of the production line can be improved without increasing the defective product rate.

  Further, in the weighing device according to the present invention, the filling correction amount calculating means is configured such that a difference obtained by subtracting the reference value from the average value is a positive value, and a difference obtained by subtracting the lower limit value from the minimum value. When the value is a positive value, a difference obtained by subtracting the lower limit value from the minimum value is set as a margin in a decreasing direction of the reference value.

  With this configuration, the filling correction amount calculating means reduces the reference value based on whether the two values of the difference between the average value and the reference value and the difference between the minimum value and the lower limit value are positive or negative. Can be calculated with high accuracy.

Further, in the weighing device according to the present invention, the filling correction amount calculating means assumes that the distribution of the measured values of the plurality of objects weighed by the measuring means follows a normal distribution, and from the average value the value obtained by subtracting the predetermined multiple of the standard deviation is regarded as the the minimum value, and calculates the front KiOsamu Seiryo.

  With this configuration, even when the number of objects to be weighed is relatively small, the filling correction amount calculating means can calculate the margin in the direction of decreasing the reference value.

In addition, the weighing device according to the present invention includes a conveying unit configured to convey the object to be weighed that has been carried in from a filling device that performs filling so that the weight of the object to be weighed W composed of a plurality of articles becomes a predetermined reference value. The weighing means for weighing the object to be weighed conveyed to the conveying means, and the weight measured by the weighing means is within a range between a lower limit value and an upper limit value predetermined according to the reference value. A weighing apparatus comprising: a non-defective / non-defective determining unit that determines an object to be weighed as a non-defective product and that determines that the object to be weighed is out of the range between the lower limit value and the upper limit value as a defective product. The average value, standard deviation, minimum value, and number of measured values of the plurality of objects weighed by the means are less than the lower limit value. Upper limit side of the object to be weighed that exceeds the value Statistical value calculating means for calculating a statistical value, including defectives, and when the difference obtained by subtracting the reference value from the upper side of the defectives from defectives of the lower side is often the average value is a positive value, Or, when the number of defective products on the lower limit side is larger than the number of defective products on the upper limit side and the difference obtained by subtracting the reference value from the average value is a negative value, the difference obtained by subtracting the reference value from the average value is corrected. It is characterized by comprising a filling correction amount calculating means for calculating the amount, and a display means for displaying the correction amount calculated by the filling correction amount calculating means .

  With this configuration, by changing the reference value of the filling device, it is possible to reliably reduce the defective product rate and improve the production line yield.

  The present invention can provide a weighing device that can improve the yield of a production line without increasing the defective product rate.

It is a perspective view which shows the external appearance of the weighing | measuring device which concerns on embodiment of this invention. It is a block diagram which shows the internal structure of the measuring apparatus which concerns on embodiment of this invention. It is a side view which shows the conveyance part of the weighing | measuring apparatus which concerns on embodiment of this invention. It is a figure which shows the statistics of the measured value of the to-be-measured object of the measuring apparatus which concerns on embodiment of this invention, and is a figure which shows the case where distribution of measured value follows a normal distribution. It is a figure which shows the statistics of the measured value of the to-be-measured object of the measuring apparatus which concerns on embodiment of this invention, and shows the actual frequency distribution of a measured value. It is a flowchart which shows operation | movement of the weighing | measuring device which concerns on embodiment of this invention.

  Hereinafter, embodiments of a weighing device according to the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 to 3, the weighing device 1 is configured to include an apparatus body 2, a transport unit 3, and a carry-in sensor 4, and a filling device 100 is connected to the front stage and a sorting unit to the rear stage. 5 is connected.

  The weighing device 1 is installed on the downstream side of a filling device 100 that constitutes a part of a production line and a belt conveyor 14 that conveys an object to be weighed from the filling device 100. The filling device 100 performs filling by, for example, combining a plurality of articles such as foods into a product having a predetermined weight (hereinafter referred to as an object to be weighed W).

  The weighing device 1 is installed on the downstream side of the belt conveyor 14 that constitutes a part of the production line, and measures the weight of the objects to be weighed W sequentially conveyed in the direction of the arrow A at a predetermined interval. The measured value is compared with the preset upper and lower reference values, respectively, and it is determined whether or not the obtained measured value is within the range of the reference value. Outside things are judged as defective.

  In addition, the determination result is displayed on the display unit 10 and is output to the selection unit 5 connected to the subsequent stage of the weighing device 1 and distributed according to the determination result.

  The apparatus main body 2 includes a conveyance control unit 6, a load sensor 21, a control circuit 7, a display unit 10, an operation unit 11, and a storage housing 2a that stores these units.

  The transport unit 3 transports various objects to be weighed W such as packaged meat, fish, processed food, and pharmaceuticals that are transported in the direction of arrow A from the belt conveyor 14. The object to be weighed W is conveyed by being accelerated or decelerated so as to have an optimum speed for measurement by the run-up conveyor 31, further conveyed by the weighing conveyor 32, and the weight is measured by the load sensor 21 while being conveyed. It has become so. In addition, the object to be weighed W is further transported to the sorting unit 5 in the subsequent stage after the weighing and is distributed.

  The transport unit 3 includes a running conveyor 31 and a weighing conveyor 32. The run-up conveyor 31 includes two rollers 31a and 31c and an endless transport belt 31b wound around these rollers 31a and 31c. The weighing conveyor 32 includes two rollers 32a and 32c and an endless transport belt 32b wound around these rollers 32a and 32c. The weighing conveyor 32 is configured such that a load is measured by a load sensor 21 disposed below the weighing conveyor 32.

  The carry-in sensor 4 is configured by a transmission photoelectric sensor including a pair of light projecting units 4 a and light receiving units 4 b, and is disposed between the run-up conveyor 31 and the weighing conveyor 32. Specifically, the light projecting unit 4a is disposed on the apparatus main body 2 side of the transport belt 32b, and the light receiving unit 4b is disposed on the other side of the transport belt 32b so as to face the light projecting unit 4a. When the object to be weighed W passes between the light projecting part 4a and the light receiving part 4b, the light receiving part 4b is shielded by the object to be weighed, so that it is detected that the carry-in of the object to be weighed W is started. It has become. The detected carry-in start signal is output to the control circuit 7 in the apparatus main body 2.

  The conveyance control unit 6 includes a drive motor 12 and a conveyance control circuit 13, and the rotation speed (rpm) of the drive motor 12 is controlled by the conveyance control circuit 13.

  The load sensor 21 is configured by a scale mechanism such as an electromagnetic balance mechanism, and the load applied to the load sensor 21 while the object to be weighed W is conveyed by the weighing conveyor 32, that is, the object to be weighed W and the weighing conveyor 32. The total weight of is to be measured. The load sensor 21 may be a scale mechanism that can measure the weight, and may be configured by a scale mechanism such as a differential transformer mechanism or a strain gauge mechanism.

  The load sensor 21 performs weighing when a preset reference time Tk elapses after the carry-in sensor 4 detects that the workpiece W has been carried into the weighing conveyor 32.

  Here, the reference time Tk is detected when the object to be weighed W starts to be loaded onto the weighing conveyor 32 by the loading sensor 4, and then the object to be weighed W is completely transferred to the weighing conveyor 32, and further from the load sensor 21. This means the time required until the output signal is stabilized, and is set in advance corresponding to the size and speed of the weighing conveyor and the size of the predetermined object W.

  Specifically, the reference time Tk is the speed of the weighing conveyor 32 (m / min), the length of the weighing conveyor 32 in the direction of arrow B (mm), and the length of the weighing object W in the direction of arrow B, which is the conveyance direction. (Mm), the size of the workpiece W, the processing capacity of the line, and other conditions.

Further, as shown in FIG. 3, the reference time Tk has elapsed, the objects to be weighed W is moved by L ₁ reaches the mass measuring position P _S from the loading start detection position P _O, metering is performed.

  In the load sensor 21, inspection conditions (parameters) such as its measurement range, measurement capability, and inspection accuracy are selected according to the size of the weighing conveyor 32 and the type (particularly size) of the object to be weighed W. According to the type of the object to be weighed W, for example, the measurement range is selected from 6 g to 600 g, and the measurement capability is selected at a maximum of 150 pieces / min.

  In this case, the reference time Tk per object W is set to a minimum of 400 msec, and the reference time Tk may be 400 msec or more. It is set according to capacity, production and other conditions.

  Since the reference time Tk is measured in a shorter time as it is closer to 400 msec, the inspection efficiency is increased, and as the distance is longer, the inspection time is longer, but the weighing accuracy is increased because it is stably conveyed on the weighing conveyor 32. Become.

  Further, according to the type of the object to be weighed W, for example, the measurement range is selected from 1 g to 300 g, and the measurement capability is selected at a maximum of 600 pieces / min. If the measurement capacity is 600 pieces / min at the maximum, the measurement time per piece of the object to be weighed W is set to a minimum of 100 msec, and the size of the object to be weighed W, the processing capacity of the line, production, etc. It is set according to the conditions.

  Since the reference time Tk is measured in a shorter time as it is closer to 100 msec, the inspection efficiency is increased. As the distance is longer, the inspection time is longer, but the weighing accuracy is increased because the weighing conveyor 32 is stably conveyed.

  As described above, in the load sensor 21, the inspection conditions (parameters) such as the range and capability are selected according to the type of the object to be weighed W.

  The control circuit 7 includes a calculation unit 22 that calculates the weight of the object W based on the weight signal output from the load sensor 21, a quality determination unit 24 that determines the quality of the object W, and various set values. (Parameter), a storage unit 23 for storing measurement results and determination results, and measuring the weight of the object W transported by the transport unit 3, and the measured weight is within a predetermined range. It is determined whether or not.

  The calculation unit 22 includes a predetermined arithmetic circuit. When the total weight signal of the object to be weighed W and the weighing conveyor 32 output from the load sensor 21 is input to the calculation unit 22, the total weight is obtained. By subtracting the weight of the weighing conveyor 32 from the signal, the weight of only the object to be weighed W is calculated, and the weight signal of the object to be weighed W is output to the pass / fail judgment unit 24.

  Further, in the calculation unit 22, a predetermined reference time Tk has elapsed after the load sensor 4 detects that the object to be weighed W has been loaded onto the weighing conveyor 32, and the weight is measured by the load sensor 21. The weight calculation is performed on the object W for each object W to be weighed. The individual weights calculated by the calculation unit 22 are stored in the storage unit 23 as calculation data.

  The storage unit 23 includes a storage medium and stores various data set in advance corresponding to the type of the object to be weighed W, and also stores the measurement value of the object to be weighed W and the pass / fail judgment result. It is like that.

  In the storage unit 23, as various data set in advance, for example, each belt speed (m / min) and length in the conveying direction (mm) of the run-up conveyor 31 or the weighing conveyor 32, each type of the object W to be weighed Size (mm) and shape, reference value of the weight of the object to be weighed W, upper limit value Ga and lower limit value Gb of the allowable range for the weight of the object to be weighed W, distance from the carry-out end of the weighing conveyor 32 to the sorting unit 5 The carry-in interval t (msec) set for each type of the object to be weighed W, the set reference time Tk, the carry-in interval t (msec) of each object to be weighed W acquired by the load sensor 21, the inspection conditions, etc. Quality data etc. are stored.

  The quality determination unit 24 includes a determination circuit and the like, and determines quality of the object W to be weighed. In the quality determination unit 24, when the weight signal of the object W output from the calculation unit 22 is received, the upper limit value Ga and the lower limit value Gb of the weight stored in advance in the storage unit 23 are read and calculated. The weight of the object to be weighed W is compared with the upper limit value Ga and the lower limit value Gb, respectively, and whether or not the weight of the object to be weighed W is within the allowable range determined by the upper limit value Ga and the lower limit value Gb. It is to be judged.

  The determination result determined by the pass / fail determination unit 24 is output to the sorting unit 5 connected to the subsequent stage of the weighing device 1 so that the weighing object W is sorted as a non-defective product or a defective product. Further, this determination result is output to the display unit 10 and displayed as a non-defective product or a defective product. Further, the determination result is output to the storage unit 23 and the measurement value and the determination result for each object W are stored. It has become so. Further, it is also output to the transport control unit 6 and used as control information for driving the transport unit 3 during normal times and stopping the transport when there is an abnormality such as when defective products continue.

  Further, the control circuit 7 calculates statistics including the average value and the minimum value from the measured values of the plurality of objects W, and decreases the reference value based on the average value, the reference value, the minimum value, and the lower limit value. An operation control unit 17 is provided for controlling various operations including the calculation of the margin.

  In addition, the operation control unit 17 switches the operation mode of the weighing device 1 between a measurement mode in which the weighing object W is weighed and a pass / fail judgment is performed, and a setting mode in which the setting operation of the weighing device 1 is performed. ing.

  As shown in FIG. 1, the display unit 10 is provided at the upper end of the apparatus main body 2 on the transport unit 3 side, and is configured by a display device such as a liquid crystal display.

  The display unit 10 displays the correction amount for the reference value of the filling device 100 calculated by the operation control unit 17. In addition, when the operation mode of the weighing device 1 is the weighing mode, the display unit 10 displays the operation state of the weighing device 1, the measured value of the object W, and the pass / fail judgment result, and the operation mode of the weighing device 1 is In the setting mode, display related to various settings is performed. The display unit 10 may be configured as a touch panel on which displayed numbers, characters, and the like are input by a touch operation, and may be used as the operation unit 11.

  The sorting unit 5 connected to the subsequent stage of the weighing device 1 includes a sorting mechanism unit 5a and a sorting conveyor 5b that transports the object W to be measured by the transport belt 5d. The sorting mechanism unit 5a includes, for example, It is composed of an extrusion type sorting mechanism. The sorting mechanism unit 5a only needs to be able to sort good products and defective products, and may be configured by a sorting mechanism such as a flipper mechanism, a dropout mechanism, or an air jet mechanism.

  The sorting mechanism unit 5a is configured to convey a belt to the object to be weighed determined to be defective while the object to be weighed W conveyed from the upstream weighing conveyor 32 is being conveyed by the sorting conveyor 5b in the arrow B direction. 5d is pushed out in the side direction and jet air is blown, and the defective weighing object W is discharged from the conveying belt 5d and is distinguished from the non-defective weighing object W. Yes.

  The conveyor belt 5d is composed of a roller 5c, a roller (not shown) disposed opposite to the roller 5c, and an endless conveyor belt wound around these rollers. The weighing object W is conveyed downstream at a predetermined speed.

  Hereinafter, the operation control unit 17 will be described in detail. In the present embodiment, the operation control unit 17 measures the statistical value including the average value, standard deviation, and minimum value of the measured values of the plurality of objects to be weighed W, and the measured value whose measured value is less than the lower limit value. Statistical values of defective products including the number and average value of defective products on the lower limit side of the product W, and the number and average value of defective products on the upper limit side of the workpiece W whose measured value exceeds the upper limit value are calculated.

  And the operation control part 17 is based on the difference between the average value and the reference value, the number of defective products on the lower limit side, and the number of defective products on the upper limit side with respect to the reference value of the filling amount (filling amount) in the filling device 100. When the minimum value is larger than the lower limit value, the correction amount is calculated. Based on the difference between the average value and the reference value and the difference between the minimum value and the lower limit value, A margin in the decreasing direction of the reference value of the filling amount is calculated, and this margin is set as a correction amount. Here, the margin in the reduction direction of the reference value is an amount by which the reference value of the filling amount in the filling device 100 can be reduced without deteriorating the defective product rate.

  Specifically, when the difference obtained by subtracting the reference value from the average value is a positive value and the difference obtained by subtracting the lower limit value from the minimum value is a positive value, the operation control unit 17 sets the lower limit from the minimum value. The difference obtained by subtracting the value is used as a margin in the decreasing direction of the reference value.

  That is, since the average value of the measured values of the object to be weighed W exceeds the reference value, the article is filled more than necessary and the yield is poor, and the minimum value of the measured value of the object to be weighed W is When the lower limit value of the pass / fail judgment is exceeded, the defective product rate does not deteriorate even if the reference value is corrected in the decreasing direction by the amount that the minimum value of the measured value of the workpiece W exceeds the lower limit value of the pass / fail judgment. Therefore, in such a case, the operation control unit 17 calculates the difference obtained by subtracting the lower limit value from the minimum value of the measured value as a margin in the reduction direction of the reference value.

  Here, the defective product rate is the ratio of the number of the objects to be weighed W that are inferior to the number of all the objects to be weighed W when the measured value is outside the range between the lower limit value and the upper limit value. The number of objects W to be weighed is N, the number of objects to be weighed W is N− when the measured value is less than the lower limit, and the number of objects W to be weighed is more than the upper limit. When the number is N +, the value is calculated by {(N −) + (N +)} / N.

  Further, as shown in FIG. 4, the operation control unit 17 assumes that the distribution of the measured values of the plurality of objects to be weighed W follows a normal distribution. The value obtained by subtracting (3σ) is regarded as the minimum value, and the margin in the decreasing direction of the reference value is set.

  That is, when it is assumed that the distribution of the measurement value of the object W follows a normal distribution, the operation control unit 17 has a lower limit value and an upper limit value within the range of −3σ (standard deviation) and + 3σ with respect to the average value μ. Since it falls within the range, the margin is calculated by regarding the average value μ−3σ as the minimum value.

  Further, as shown in FIG. 5, when using the actual frequency distribution as the measurement value distribution of the object W, the operation control unit 17 calculates the margin using the actual minimum value. . Whether the normal distribution or the actual frequency distribution is adopted as the distribution of the measurement values can be switched by an operation from the operation unit 11.

  Further, when there is a defective product on the lower limit side, the operation control unit 17 has a higher number of defective products on the upper limit side than the number of defective products on the lower limit side, and a positive value is obtained by subtracting the reference value from the average value. Or, if the number of defective products on the lower limit side is larger than the number of defective products on the upper limit side and the difference obtained by subtracting the reference value from the average value is a negative value, the difference obtained by subtracting the reference value from the average value is used as the correction amount. It comes to calculate.

  The amount of correction was calculated based on the difference between the average value and the reference value, the number of defective products on the lower limit side, and the number of defective products on the upper limit side. The difference between the difference and the average value of the defective products on the upper limit side and the upper limit value may be obtained, and the correction amount may be calculated from the magnitude relationship of the difference.

  Next, the operation of the weighing device 1 according to the present embodiment will be described with reference to FIG.

  First, when the carry-in sensor 4 detects that the object W has been loaded (step S1), the load sensor 21 measures the total load of the loaded object W and the weighing conveyor 32 (step S2). ), The measurement value of only the workpiece W is calculated by the calculation unit 22 (step S3). Next, the storage unit 23 stores the calculated measurement value (step S4).

  The processing of step S1 to step S4 is repeatedly performed until the number of objects to be weighed W, the number of lots, the measurement period, and the like reach predetermined values.

  Next, the operation control unit 17 determines whether or not the number of objects W to be weighed, the number of lots, the measurement period, etc. has reached a predetermined value or more (step S5), and if this determination is “Yes”. For example, the statistical value of the measurement value of the plurality of objects W is calculated (step S6).

  In step S <b> 6, the operation control unit 17 uses the average value (μ) and the standard deviation (σ) of the measured values of the plurality of measured objects W as the statistical values of the measured values of the plurality of objects W. Then, a value including a defective product on the lower limit side of the workpiece W whose measured value is less than the lower limit value and a defective product on the upper limit side of the measured item W whose measured value exceeds the upper limit value is calculated.

  Next, the operation control unit 17 compares the average value in the calculated statistical value with a preset reference value, and calculates a difference obtained by subtracting the reference value from the average value (step S7).

  Next, the operation control unit 17 determines the correction direction of the filling amount, that is, whether the stitch amount is to be increased or decreased based on the calculated difference (step S8).

  Specifically, the operation control unit 17 determines that the measured value exceeds the upper limit value and becomes a defective product when the measured value exceeds the upper limit value, rather than the number (N−) of the weighing objects W that are defective when the measured value is less than the lower limit value. When the number (N +) of the objects to be weighed is larger and the difference obtained by subtracting the reference value from the average value is a positive value, it is determined that the correction direction of the filling amount is the decreasing direction, and the weighing value is The number of objects to be weighed (N−) that became defective products below the lower limit value is greater than the number of objects to be weighed (N +) that exceeded the upper limit value and became defective products, and the average value When the difference obtained by subtracting the reference value from is a negative value, it is determined that the correction direction of the filling amount is the increasing direction.

  Next, the operation control unit 17 determines the correction amount in the correction direction determined in step S8 (step S9).

  In step S <b> 9, the operation control unit 17 calculates a correction amount with respect to the reference value so that the ratio of defective products is reduced. Specifically, when the minimum value is larger than the lower limit value, the operation control unit 17 subtracts three times the standard deviation from the average value when the distribution of the measured values is assumed to follow a normal distribution. The value obtained by subtracting the lower limit value from the value obtained by subtracting three times the standard deviation from the average value is determined as the correction value for the filling amount. Here, the correction amount of the filling amount is (average value −3σ) −lower limit value, and indicates the difference between the position of the average value −3σ and the lower limit value in FIG.

  In step S9, when the minimum value is larger than the lower limit value, the operation control unit 17 subtracts the lower limit value from the minimum value as the correction amount of the filling amount when the actual frequency distribution is used as the distribution of the measured value. The determined value is determined (step S9). The correction amount of the filling amount in this case is a value obtained by subtracting the lower limit value from the actual minimum value in the actual frequency distribution of FIG.

  Then, the display unit 10 displays the correction direction and the correction amount determined in step S9. When the minimum value is larger than the lower limit value and the correction direction is the decreasing direction, the display unit 10 displays the correction amount at this time as a margin in the reference value decreasing direction (step S10).

  As described above, in the weighing device 1 according to the present embodiment, the average value, standard deviation, minimum value, and measured value of the measured values of the plurality of objects W measured by the calculation unit 22 are less than the lower limit value. The statistical value including the number of defective products on the lower limit side of the object to be weighed W and the number of defective products on the upper limit side of the object to be weighed whose measured value exceeds the upper limit value is calculated, and based on the calculated statistical value, the defective product is calculated. It is characterized by comprising an operation control unit 17 for calculating a correction amount with respect to a reference value such that the ratio of the ratio decreases, and a display unit 10 for displaying the calculated margin.

With this configuration, when the user reduces and changes the reference value of the filling device 100 according to the correction amount displayed on the display unit 10, the average value of the objects to be weighed W measured by the weighing device 1 approaches the reference value. Therefore, the yield of the production line can be improved.
Further, in the weighing device 1 according to the present embodiment, when the minimum value is larger than the lower limit value, the operation control unit 17 is based on the difference between the average value and the reference value and the difference between the minimum value and the lower limit value. Thus, the amount of correction is calculated by calculating the margin in the decreasing direction of the reference value so that the minimum value is equal to or greater than the lower limit value.

  With this configuration, the margin in the reduction direction of the reference value is calculated so that the minimum value is equal to or greater than the lower limit value, so that the defective product rate increases even if the reference value of the filling device 100 is changed in the reduction direction. There is nothing. Therefore, the yield of the production line can be improved without increasing the defective product rate.

  Further, in the weighing device 1 according to the present embodiment, the motion control unit 17 is such that the difference obtained by subtracting the reference value from the average value is a positive value, and the difference obtained by subtracting the lower limit value from the minimum value is a positive value. In this case, the difference obtained by subtracting the lower limit value from the minimum value is used as a margin in the decreasing direction of the reference value.

  With this configuration, based on whether the two values of the difference between the average value and the reference value and the difference between the minimum value and the lower limit value are positive or negative, the operation control unit 17 decreases the reference value. The margin can be calculated with high accuracy.

  Further, in the weighing device 1 according to the present embodiment, the operation control unit 17 assumes that the distribution of the measurement values of the plurality of objects W measured by the calculation unit 22 follows a normal distribution, and calculates the average value. A value obtained by subtracting a predetermined number of times of the standard deviation is regarded as the minimum value, and a margin in the decreasing direction of the reference value is calculated and used as a correction amount.

  With this configuration, even when the number of objects to be weighed W is relatively small, the operation control unit 17 can calculate a margin in the direction of decreasing the reference value.

  Further, in the weighing device 1 according to the present embodiment, the operation control unit 17 has a positive value when the difference between the number of defective products on the upper limit side is larger than the number of defective products on the lower limit side and the reference value is subtracted from the average value, or When the number of defective products on the lower limit side is larger than the number of defective products on the upper limit side and the difference obtained by subtracting the reference value from the average value is a negative value, the difference obtained by subtracting the reference value from the average value is calculated as the correction amount. And

  With this configuration, by changing the reference value of the filling apparatus 100, it is possible to reliably reduce the defective product rate and improve the production line yield.

  As described above, the weighing device according to the present invention has an effect that the yield of the production line can be improved without increasing the defective product rate. It is useful as a weighing device that determines the quality of an object to be weighed based on the above.

DESCRIPTION OF SYMBOLS 1 Measuring apparatus 2 Apparatus main-body part 2a Storage housing | casing 3 Conveyance part (conveyance means)
DESCRIPTION OF SYMBOLS 4 Carry-in sensor 4a Light projection part 4b Light receiving part 5 Sorting part 5a Sorting mechanism part 5b Sorting conveyor 5c, 31a, 31c, 32a, 32c Roller 5d, 31b, 32b Conveyance belt 6 Conveyance control part 7 Control circuit 10 Display part (display means) )
DESCRIPTION OF SYMBOLS 11 Operation part 12 Drive motor 13 Conveyance control means 14 Belt conveyor 17 Operation control part (Statistical value calculation means, filling correction amount calculation means)
21 Load sensor 22 Calculation unit (measuring means)
23 storage unit 24 pass / fail judgment unit (pass / fail judgment means)
31 Run-up conveyor 32 Weighing conveyor 100 Filling device W Object to be weighed

Claims (3)

Conveying means (3) for conveying the object to be weighed in from a filling device (100) that performs filling so that the weight of the object to be weighed W composed of a plurality of articles becomes a predetermined reference value;
Weighing means (22) for weighing the object to be weighed conveyed to the conveying means;
The weight measured by the weighing means is determined as a non-defective product when the weight is within a range between a lower limit value and an upper limit value predetermined according to the reference value, and the weight is determined as the lower limit value and the upper limit value. in the metering device (1) provided with the a good determination means you determine the objects to be weighed as a defective product (24), is outside the scope of the,
The average value, standard deviation, minimum value, and measured value of the plurality of objects weighed by the weighing means are less than the lower limit value. A statistical value calculating means (17) for calculating a statistical value including the number of defective products on the upper limit side of the object to be weighed which is more than the upper limit value;
When the minimum value is larger than the lower limit value, the difference obtained by subtracting the reference value from the average value is a positive value, and when the difference obtained by subtracting the lower limit value from the minimum value is a positive value, Filling correction amount calculating means (17) for calculating a difference obtained by subtracting the lower limit value from the minimum value as a correction amount in the decreasing direction of the reference value ;
A weighing device comprising: display means (10) for displaying the correction amount calculated by the filling correction amount calculation means. The filling correction amount calculating means assumes that the distribution of the measured values of the plurality of objects weighed by the measuring means follows a normal distribution, and is a value obtained by subtracting a predetermined number of standard deviations from the average value. There weighing apparatus according to claim 1, characterized in that to calculate the regarded as the the minimum value, before KiOsamu Seiryo. Conveying means (3) for conveying the object to be weighed in from a filling device (100) that performs filling so that the weight of the object to be weighed W composed of a plurality of articles becomes a predetermined reference value;
Weighing means (22) for weighing the object to be weighed conveyed to the conveying means;
The weight measured by the weighing means is determined as a non-defective product when the weight is within a range between a lower limit value and an upper limit value predetermined according to the reference value, and the weight is determined as the lower limit value and the upper limit value. In a weighing device (1) comprising: a quality determination means (24) for determining, as a defective product, the object to be weighed that is out of the range of
The average value, standard deviation, minimum value, and measured value of the plurality of objects weighed by the weighing means are less than the lower limit value. A statistical value calculating means (17) for calculating a statistical value including the number of defective products on the upper limit side of the object to be weighed which is more than the upper limit value;
Before SL when the difference obtained by subtracting the reference value from defectives many the average value of the lower limit of defectives than the upper limit is a positive value, or, defectives of the lower side is the upper side of defectives A filling correction amount calculating means (17) for calculating, as a correction amount, a difference obtained by subtracting the reference value from the average value when a difference obtained by subtracting the reference value from the average value is a negative value ;
It said display means for displaying the correction amount calculated by the filling correction amount calculating means (10), weighing apparatus you comprising the.

Images