JP2007163421A - Length standard - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a length standard capable of providing a means for knowing a temperature and a length in measurement by the length standard, provided with a network interface, and capable of outputting the temperature, calibration information and the like of the standard to an outside. <P>SOLUTION: This length standard 1 has a temperature sensor, a display part 8, and a built-in storage device, or the network interface, and is provided with a function for measuring and displaying the temperature in the measurement by the length standard 1, and a function for calculating and displaying the length in the measurement, based on information on the length standard 1 recorded in the built-in storage device, or the temperature and the calibration information of the standard are transmitted to a remote site via the network interface. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes any one of a temperature sensor, a temperature measurement result display unit, a length calculation function during measurement, a length calculation result display unit, a network interface, and an electronic storage device for a unique identifier, Or, it relates to a standard device to which a plurality is added.

  For accuracy evaluation of length measuring machines such as CMMs, a length standard with a known length (referred to as calibration value) in the standard state (20 ° C for length measurement) is used for accuracy evaluation. It is only necessary to measure the difference between the calibration value and the measured value by using a length measuring machine (referred to as an “evaluated measuring machine”) that is the object of the measurement. This accuracy evaluation work is sometimes referred to as calibration, but in the following, it will be referred to as accuracy evaluation work as a representative.

  Since the accuracy evaluation work is not always performed at 20 ° C., the length standard device expands and contracts due to a temperature change. Therefore, when working, it was necessary to prepare a separate thermometer and measure the temperature of the length standard. It may also be necessary to know the actual length of the length standard at work. In this case, it was necessary to calculate from the temperature and the thermal expansion coefficient.

  Usually, since the length measuring machine such as a three-dimensional measuring machine is large in size, the above-described accuracy evaluation work is performed by an accuracy evaluation operator on site. In recent years, it has become possible to transport only the length standard to the site and perform accuracy evaluation work by remote control using an information network such as the Internet. Even when performing accuracy evaluation work by remote control, the temperature standard length information and length information at the time of measurement are important. Therefore, it is necessary to transport the thermometer together with the length standard, and a local worker other than the system evaluation worker attaches the thermometer to the length standard and measures it.

  A further problem when performing remote calibration is that there is no effective means of confirming that the length standard sent by the accuracy assessment operator is in use.

  In addition, when measuring the length of a certain object using a length measuring machine, the object is expanded and contracted by thermal expansion as compared with the case of 20 ° C. However, in length measurement, the measured value is generally converted into a state at 20 ° C. and displayed. Therefore, in order to correct the expansion and contraction, the temperature of the object at the time of measurement is measured.

  For this purpose, many length measuring machines with thermometers are sold, for example, most of the three-dimensional measuring machines have the function. Further, a measuring instrument having a temperature measuring function added to a measuring instrument which is a very simple length measuring machine has been devised (see Patent Document 1).

  As described above, there is a conventional length measuring machine with a temperature correction function added, but no length standard has a temperature measuring function. The length standard is used as a standard when evaluating the accuracy of a length measuring machine, or as a reference standard when using a length measuring machine using the comparative measurement principle. Are completely different.

The length standard that has the above-mentioned problems other than temperature measurement, such as the function to calculate and display the length at the time of measurement, the communication function, and the unique ID number holding function, has not been proposed so far. Has never been realized before.
Japanese Utility Model Publication No. 58-36302

  As described above, a problem in using the conventional length standard for accuracy evaluation work of the length measuring machine is that it is necessary to prepare a thermometer separately from the length standard.

  Furthermore, it is necessary to attach a thermometer to the length standard for each measurement. Since the thermal contact between the thermometer and the length standard device is a major error factor in temperature measurement, installation requires skill and caution. In particular, when the evaluation work is performed by remote operation, a local worker performs this work, which may cause a larger error.

  Regarding the work for obtaining the length during measurement, a work for calculating from the result of temperature measurement and the thermal expansion coefficient was necessary. Even if temperature measurement and length calculation at the time of measurement are performed automatically using a computer, parameters unique to the length standard, such as calibration values and thermal expansion coefficients, must be entered in advance. It was.

  In addition to the above-mentioned problems, the problems in remote accuracy evaluation work need to be prepared separately with hardware and software that transfers the temperature measurement results via the Internet, in addition to the measurement results from the measuring machine to be evaluated. Is that there is.

  Furthermore, the problem in the accuracy evaluation work by remote control is how to verify whether the correct length standard is used.

  In order to solve the above problems, the present invention provides a length standard having a temperature sensor for measuring the temperature of the length standard at the time of measurement. This standard device preferably includes a display that displays the temperature measured by the temperature sensor.

  In order to solve the above problems, the present invention has a storage device, and records information on the length standard including the calibration value of the length standard and the thermal expansion coefficient in the storage device, and can output the information. A length standard is provided. The standard device preferably has a display device for displaying information.

  In order to solve the above problems, the present invention has a storage device, records information on the length standard including the unique identification number of the length standard in the storage device, and outputs the information. Provide a featured length standard. The standard device preferably has a display device for displaying information.

  In order to solve the above problems, the present invention is a standard device having a temperature sensor for measuring the temperature of a length standard device at the time of measurement and a storage device, wherein the storage device is a temperature measured by the temperature sensor. Information on the length standard including the calibration value, thermal expansion coefficient, and unique identification number of the length standard, and the information can be output, and the temperature and the length recorded in the storage device can be output. There is provided a length standard having a function of calculating the length of a length standard from measurement information. It is preferable that the standard device has a display for displaying the length of the length standard device at the time of measurement.

  There are a plurality of temperature sensors of the standard device, and it is preferable that the influence of the temperature distribution of the length standard device and the error of the temperature sensor is reduced by averaging the measurement results of the plurality of temperature sensors. .

  As described above, the length standard of the present invention has a temperature measurement and display function, a length calculation and display function during measurement, a network interface, and an electronic storage device for a unique identifier. The effects obtained by these features are as follows.

  The first effect of adding a thermometer to the length standard is that it is not necessary to prepare a separate thermometer in the evaluation work of the length measuring machine, and the labor and cost required for it can be reduced. It is necessary to calibrate the length standard regularly, but by calibrating the thermometer at the same time as the length calibration, it can be used as a length standard regardless of the conditions used alone. Can function. In addition, since the thermometer is attached in advance, it is possible to avoid problems such as a difference in the place where the thermometer is attached and a problem that a correct measurement result cannot be obtained due to the skill of the attaching operator.

  The second effect of adding a thermometer to the length standard is that the thermometer is pre-installed, so that correct measurement results cannot be obtained due to differences in installation location or the skill of the installation operator. It is possible to avoid such problems.

  The third effect of adding the thermometer to the length standard is that the temperature distribution problem can be reduced. The length standard has a uniform temperature distribution and a temperature distribution. By pasting a plurality of thermometers and averaging the measurement results, the influence of the distribution can be reduced. Furthermore, a temperature difference also occurs between the length standard surface and the inside thereof. When considering the expansion and contraction of the length standard due to heat, the more important is the internal temperature, but it is difficult for the user to attach a thermometer inside the length standard unless it is the manufacturer. On the other hand, with the length standard of the present invention, it is easy for the manufacturer to attach the thermometer at the optimum position, and a more accurate measurement result can be obtained.

  The effect of adding the temperature measurement result display section to the length standard is that the user can easily know the temperature length at the time of measurement without preparing a separate display section. Furthermore, when another measuring machine is attached to the length standard boil, it is necessary to place the display unit next to the length standard. CMMs and machine tools have mechanical moving parts, especially table-moving CMMs, where a length standard is placed on the moving table for measurement. Although it is not preferable that they are connected, this problem can be solved by using a length standard with a display unit.

  The effect of adding the display function to the length calculation function at the time of measurement is that the user is freed from the work himself, and the value is displayed on the display part, so that the user is easier. In addition, the measurement length can be known in real time.

  The effect of adding a network interface is that information can be taken out to the outside. In addition to the above temperature and length at the time of measurement, various information such as the following individual identification symbol, calibration value, calibration date, thermal expansion coefficient, and manufacturer name can be extracted if stored in advance in the length standard. It is a great advantage for the user that it is not necessary to separately manage the length standard and these pieces of information printed on paper, for example. When the length standard is used to calibrate the length measuring device by remote control, it is a great advantage that temperature information at the time of measurement can be obtained in real time via a network.

  The effect of storing and retrieving the individual identification symbol in the storage device attached to the length standard is the same as that described in the network interface above, especially when calibrating the length measuring machine by remote control. Useful to determine if the length standard used is legitimate.

  The present invention provides such a length standard and a length standard that solves the problems that arise when performing accuracy evaluation work of a length measuring machine using the length standard. More specifically, there is no need to prepare a thermometer separately from the length standard, no work to attach the thermometer to the length standard, and no need to obtain the measurement length. belongs to. In the case of remote control, there is no need for a device for transferring the temperature measurement result, and a means for reliably identifying the length standard used at the time of measurement is provided.

  By using the length standard to which these are added, the user can know the temperature from the display without taking the trouble of attaching the thermometer, and the length standard at the time of measurement from the measured temperature. You can know the length immediately.

  When performing remote calibration, the calibration value can be known in real time from a remote location by simply connecting the network interface to a network such as the Internet.

  Furthermore, in the case of remote calibration, it is important to check whether a valid gauge is being used, but the length standard itself has a function of transmitting a unique identification symbol, which is connected to the above network interface. For example, it is possible to provide a means for verifying the correctness when performing remote calibration.

  Here, a ball bar and a step gauge are shown as typical length standard devices.

  FIG. 1 shows the appearance of the ball bar. (1) is a ball bar body which is one of the length standards. Balls (3) are arranged in a row on the frame (2). The number of balls is two or more.

  Commercially available ballbar frames are made of various materials such as aluminum, steel, carbon fiber, and glass, and are usually designed to have a structure that resists deflection. In this embodiment, the frame (2) has a quadrangular prism shape. A variety of frame materials are used, each having various advantages and disadvantages such as strength, degree of thermal expansion, price, and robustness. The present invention has a great effect when a material having a large thermal expansion is used.

  The balls (3) are firmly fixed to the frame (2), and their intervals are calibrated in advance. In order to keep the distance between the balls stable, it is not only mounted on the frame, but also supported by another rod between the balls, or a simple shape with only two balls connected by a rod. Although some devices have been devised, they are all length standard devices in which the interval between balls is a calibration value, and the present invention can be applied. Balls 3 of various materials, sizes and surface conditions are selected according to the purpose of use of the length standard.

  FIG. 2 shows only the electrical system of the ball bar. A thermometer (4) is attached inside the frame (2). The temperature sensed by the thermometer (4) is sent to a small board computer (5).

  Necessary electrical components such as a small central processing unit (6) and a nonvolatile memory (7) are attached to the board computer (5). Parts other than these are omitted in the figure.

  Various commercially available central processing units (6) can be used. If a low power consumption type is used, it can be operated with the battery 9, and it is not necessary to connect a power cable, and handling becomes easy. Other desirable functions for the central processing unit (6) are small size, input / output function for acquiring data from the thermometer (4), analog / digital conversion function, and output function to the external display (8). Interface functions for programming and data input / output.

  As the central processing unit (6), for example, a microcomputer (for example, trade name PIC16F877) manufactured by Microchip Technology Inc. can be used. This microcomputer has all the above features.

  In this embodiment, three temperature sensors (4) are attached, all of the data can be acquired using the central processing unit (6), and the average value is used as the temperature of the length standard. As the temperature sensor, a platinum resistance thermometer, thermistor, thermocouple or the like can be used.

  Since the temperature is displayed on the external display (8), the user can know the temperature of the length standard in real time. The switch (9) can have various functions according to the program of the central processing unit 6. For example, if the temperature of three temperature sensors is displayed when the switch is pressed, the user can know the temperature distribution information of the length standard. If the temperature distribution is large, measures such as improving the temperature environment and waiting for the temperature to become uniform over time are usually taken.

  A non-volatile memory 7 is mounted on the board computer (7). Since it is non-volatile, information in the memory is retained even when the power is turned off. The most important information to be recorded is the calibration value of the length standard, the coefficient of thermal expansion, and the unique identification symbol. In addition, various additional information such as a calibration date, a proofreader name, and a manufacturer name can be stored. In FIG. 2, the power switch is omitted.

  If these electric systems are of low power consumption type, the battery (10) can be operated without being connected to a commercial power source. In this case, the length standard (1) is cable-less, and the usability is greatly improved.

  FIG. 3 shows a second embodiment of the present invention. This length standard is called a step gauge (11). The ball bar uses a ball, whereas the surface (12) is used as a measurement site.

  The second embodiment is an example in which a thermometer and other electrical components cannot be built in the length standard device due to restrictions due to size and structure. The external display (8), switch (9), board computer (5) A box (13) in which the battery (10) (not shown in FIG. 3) and the battery (10) (not shown in FIG. 3) are integrated is attached to the outside of the length standard. In this example, only one thermometer (4) is attached.

  In addition to the functions of the first embodiment, the network interface (14) is provided in the second embodiment. By connecting the cable (15) there, the user can take out data such as temperature and measurement length.

  When this length standard is used in remote operation, the status of the length measuring device at the time of measurement can be monitored from a remote place by connecting the cable (15) to a wide area network such as Ethernet (registered trademark). It is also possible to check whether a valid length standard is used by monitoring the unique identification symbol. When using Ethernet (registered trademark), if the MAC (Media Access Control address) address, which is a unique number assigned to each network interface, is used as a unique identifier, it is convenient that no additional device is required. is there.

  In the examples, the ball bar and the step gauge are shown as the length standard, but other than this, the shape of the length standard is various, and the object has sufficient stability and strength as the length standard. Anything can be a length standard if its length is calibrated.

  Since the accuracy evaluation procedure is the same as that for the length measuring machine for all devices that have a positioning function in space such as machine tools and industrial robots, the length standard of the present invention is used for these devices. It can be used for accuracy evaluation work of all devices.

It is a perspective view which shows the external view of Example 1 of this invention. It is a perspective view which shows the internal structure of Example 1 of this invention. FIG. 6 is a perspective view showing an external view of Example 2.

Explanation of symbols

1 Ball bar 2 Frame 3 Ball 4 Temperature sensor 5 Board computer 6 Central processing unit 7 Non-volatile memory 8 Display 9 Switch 10 Battery 11 Step gauge 12 Measuring surface 13 Electrical box 14 Network interface 15 Network cable

Claims (8)

  A length standard having a temperature sensor for measuring the temperature of the length standard at the time of measurement.   The length standard according to claim 1, further comprising a display for displaying a temperature measured by the temperature sensor.   A length standard having a storage device, wherein information related to the length standard including a calibration value of the length standard and a thermal expansion coefficient is recorded in the storage device, and the information can be output.   A length standard having a storage device, wherein information related to the length standard including the unique identification number of the length standard is recorded in the storage device, and the information can be output.   5. A length standard according to claim 3, further comprising a display for displaying the information. A temperature sensor that measures the temperature of the length standard at the time of measurement, and a standard device having a storage device, wherein the storage device includes the temperature measured by the temperature sensor, the calibration value of the length standard device, the heat Record information about length standard including expansion coefficient and unique identification number, and output the above information,
A length standard having a function of calculating the length of a length standard at the time of measurement from information on the temperature and the length standard recorded in the storage device.   The temperature sensor includes a plurality of temperature sensors, and the measurement results of the temperature sensors are averaged to reduce the influence of the temperature distribution of the length standard and the error of the temperature sensor. The length standard according to 2 or 6. The length standard according to claim 6, further comprising a display for displaying the length of the length standard at the time of measurement.

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