JP2011158275A - Encoder attached to motor or apparatus driven by motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an encoder which can detect vibration given directly to the encoder, and is small in size and low in expense. <P>SOLUTION: In the encoder (10) having a printed circuit board (12) attached to a housing (11) including a vibration detecting part (20) which contains a component of which the state of continuity is changed when the vibration of a prescribed reference value or larger is given, the vibration detecting part is provided in at least one of the housing, the printed circuit board and a part between the housing and the printed circuit board, and moreover, has an abnormality determining part (30) which determines the state of an abnormality based on the change in the state of the continuity of the component contained in the vibration detecting part. Furthermore, the vibration detecting part may have a notifying part (40) which makes notifies the state of the abnormality when the state is determined by the abnormality determining part. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an electric motor provided in a robot or a machine tool or an encoder attached to a device driven by such an electric motor.

  The robot or machine tool is driven by one or more electric motors. An encoder is attached to an electric motor or a device driven by such an electric motor (hereinafter simply referred to as “electric motor”), and is used to detect the position of an output shaft or the like.

  By the way, the encoder is also attached to the electric motor of the press machine. In such a case, the encoder is often subjected to excessive vibration and / or shock (hereinafter simply referred to as “vibration”). Since the encoder is usually composed of a large number of electronic components, even if the electric motor can withstand excessive vibration of the press machine, the encoder may not withstand such vibration and may be damaged.

  For this reason, an allowable value for vibration is preset in the encoder. If the encoder continues to receive vibrations exceeding this allowable value, the encoder may be damaged, and information from the encoder may not be acquired in an important aspect. For this reason, it is required that the user can recognize that the encoder is vibrated.

  For example, Patent Document 1 discloses a configuration in which an acceleration sensor is provided in an electric motor to which an encoder is attached. Patent Document 2 discloses a configuration in which such an acceleration sensor is provided inside an encoder.

JP 2002-186281 A JP 2004-325171 A

  However, in the configuration of Patent Document 1, since the acceleration sensor itself is separated from the encoder, the vibration applied to the encoder cannot be directly detected. Further, in the configuration of Patent Document 2, since it is necessary to mount the acceleration sensor and related circuits inside the encoder, it is difficult to reduce the size of the encoder, and the manufacturing cost of the encoder also increases.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a small and inexpensive encoder capable of detecting vibration directly applied to the encoder.

  In order to achieve the above-described object, according to a first invention, in an encoder having a printed circuit board attached to a housing, vibration including a component whose conduction state changes when vibration exceeding a predetermined reference value is applied. A vibration detection unit, the vibration detection unit is installed in at least one of the housing, the printed circuit board, and between the housing and the printed circuit board, and further included in the vibration detection unit An encoder is provided that includes an abnormality determination unit that determines an abnormal state based on a change in the conduction state of a component.

  According to a second invention, in the first invention, the component included in the vibration detection unit is broken by fatigue failure and becomes non-conductive when vibration exceeding the predetermined reference value is applied. It is the part made.

  According to a third aspect, in the first aspect, the component included in the vibration detection unit is formed of two components that are in a non-contact state with each other, and the component includes the component as described above. This is a component that is brought into contact with each other and brought into a conducting state when vibrations exceeding a predetermined reference value are applied.

  According to a fourth aspect, in the first aspect, the information processing apparatus further includes a notification unit for notifying an abnormal state when the abnormal state is determined by the abnormality determining unit.

  According to a fifth aspect, in the fourth aspect, the apparatus includes a plurality of vibration detection units and a plurality of abnormality determination units corresponding to the plurality of vibration detection units, respectively. The reference values of the parts included in the part are made different from each other.

  In the first invention, when vibration is applied to the encoder, stress associated with the vibration is generated in the vibration detection unit. When a predetermined level of stress is generated in the vibration detection unit a plurality of times, the conduction state of the components of the vibration detection unit changes. The conduction state of the component of the vibration detection unit can be determined, for example, through a potential applied to the component. If the conduction state of the component of the vibration detection unit changes, it can be determined that the component is in an abnormal state. Further, since the components of the vibration detector are attached to the encoder housing and / or the printed circuit board, vibrations directly applied to the encoder can be detected. Furthermore, in the first invention, an acceleration sensor is not required, and parts of the vibration determination unit are inexpensive. Therefore, the encoder can be made small and inexpensive.

  In the second invention, the vibration detection unit can be formed with a relatively simple configuration. In this case, when the potential applied to the components of the vibration detection unit becomes approximately zero, it can be determined that the state is abnormal.

  In the third aspect of the invention, the vibration detector can be formed with a relatively simple configuration. In this case, when the potential flowing through the component of the vibration detection unit exceeds a predetermined positive value, it can be determined that the state is abnormal.

  In the fourth aspect of the invention, the notification unit allows the user to recognize that the encoder is in an abnormal state. The notification unit outputs a signal that can be visually and / or audibly recognized by the user. Therefore, the user can predict the approximate time when the encoder will fail based on the signal from the notification unit.

  In the fifth aspect of the invention, the magnitude of vibration determined by each of the plurality of abnormality determination units is different, so that the notification unit can perform notification with different urgency levels depending on each abnormality determination unit.

It is sectional drawing of the encoder based on 1st embodiment of this invention. It is a top view of a printed circuit board. FIG. 2 is a circuit diagram of the encoder shown in FIG. 1. It is a fragmentary perspective view of the encoder based on other embodiment of this invention. It is a fragmentary perspective view of the encoder based on further another embodiment of this invention. It is sectional drawing of the encoder based on 2nd embodiment of this invention. FIG. 7 is a circuit diagram of the encoder shown in FIG. 6. It is a fragmentary perspective view of the encoder based on 3rd embodiment of this invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following drawings, the same members are denoted by the same reference numerals. In order to facilitate understanding, the scales of these drawings are appropriately changed.
FIG. 1 is a sectional view of an encoder according to a first embodiment of the present invention. As shown in FIG. 1, the encoder 10 includes a printed circuit board 12 attached to a housing 11. The printed circuit board 12 includes an electronic component 15 composed of various components. Although not shown in the drawings, it is assumed that the encoder 10 is provided in a motor of a robot or a machine tool or a device that drives the motor.

  In the embodiment shown in FIG. 1, the vibration detection unit 20 is disposed between the housing 11 and the printed circuit board 12. Specifically, as can be seen from FIGS. 2 and 1 which are top views of the printed circuit board, the vibration detection unit 20 connects the upper surface of the printed circuit board 12 and a certain surface of the housing 11. Note that the vibration detection unit 20 may be installed only on the printed circuit board 12 of the encoder 10 or may be installed only on the housing 11.

  The vibration detection unit 20 includes at least a part made of a conductive material whose conduction state changes when a vibration exceeding a predetermined reference value is applied, or the vibration detection unit 20 is entirely formed of a conductive material. , May have such characteristics. FIG. 3 is a circuit diagram of the encoder shown in FIG. In FIG. 3, one end C of the vibration detection unit 20 is connected to a high potential part of the printed circuit board 12, for example, a part having a potential of 5 V, and the other end B of the vibration detection unit 20 is a low potential part of the printed circuit board 12. For example, it is connected to the portion of potential 0V.

  As shown in FIG. 3, the encoder 10 includes an abnormality determination unit 30 mainly composed of a comparator 31. One input end of the comparator 31 is connected to the above-described low potential portion of the printed circuit board 12, and the other input end is connected to the reference potential E. The output terminal of the comparator 31 is connected to the notification unit 40.

  The reference potential E is smaller than the high potential portion of the printed circuit board 12 and larger than the low potential portion, and varies depending on the characteristics of the vibration detection unit 20. As can be seen from FIG. 3, the comparator 31 compares the partial pressure at the point A related to the vibration detection unit 20 with the reference potential E. When the potential at point A is large, a low level signal is output, and when the reference potential E is large, a high level signal is output.

  As described above, the encoder 10 according to the present invention is attached to an electric motor of a robot or a machine tool. Therefore, during the operation of the robot or machine tool, vibrations generated by the robot or machine tool may be applied to the encoder 10. In such a case, the printed circuit board 12 and the housing 11 move relatively, and stress is generated in the vibration detection unit 20. Then, when a vibration equal to or greater than a predetermined reference value is applied to the vibration detection unit 20 for a predetermined number of times, the vibration detection unit 20 or parts of the vibration detection unit 20 are broken due to fatigue failure (see “X” in FIG. 3). ).

  When the encoder 10 is operating normally, since the potential at the point A related to the vibration detection unit 20 is higher than the reference potential E, a low level signal is output. However, when the vibration detection unit 20 breaks, the potential at the point A becomes smaller than the reference potential E, so the output from the comparator 31 becomes a high level signal.

  The notification unit 40 is activated by this high-level signal, and notifies the user that the encoder 10 is in an abnormal state (in the first embodiment, the vibration detection unit 20 is broken). The notification unit 40 outputs a visual alarm using a lamp or a liquid crystal display and / or an audible alarm using a speaker. As a result, the user can recognize that the encoder 10 is in an abnormal state, that is, the encoder 10 is subject to vibrations exceeding the allowable value.

  At this stage, although the encoder 10 itself has not yet failed, the user can predict an approximate time when the encoder 10 will fail when the encoder 10 is continuously used. Therefore, the user can perform replacement and repair in advance before the encoder 10 breaks down.

  Thus, in the present invention, it is possible to determine whether or not the encoder 10 is in an abnormal state through a change in the conduction state of the vibration detection unit 20. In addition, since the vibration detection unit 20 is attached to the housing 11 and / or the printed circuit board 12 of the encoder 10, it will be understood that vibrations directly applied to the encoder 10 can be detected in the present invention. This is particularly advantageous when the motor can withstand excessive vibrations but the encoder 10 cannot withstand such vibrations.

  Furthermore, in the present invention, an acceleration sensor as in the prior art is not required, and it is sufficient that the vibration detection unit 20 includes a component made of a conductive material. Thus, it will be appreciated that the encoder 10 can be made small and inexpensive.

  FIG. 4 is a partial perspective view of an encoder according to another embodiment of the present invention. In FIG. 4, illustration of the printed circuit board 12 and the abnormality determination unit 30 of the encoder 10 is omitted for the sake of brevity. Such an abnormality determination unit 30 is assumed to be mounted on the housing 11 or the printed circuit board 12.

  As shown in FIG. 4, two concave portions 11 a and 11 b are formed on the upper surface of the frame-shaped housing 11 so as to face each other. And the elongate vibration detection part 20 is arrange | positioned at the recessed parts 11a and 11b like a both-ends support beam, and the both ends of the vibration detection part 20 are being fixed to these recessed parts 11a and 11b by the fixing tool 16. FIG. That is, in the embodiment shown in FIG. 4, the vibration detection unit 20 is attached only to the housing 11.

  In the embodiment shown in FIG. 4, when vibration is applied to the encoder 10, the housing 11 and the vibration detection unit 20 move relatively, and stress is generated in the vibration detection unit 20. And if the vibration more than a predetermined standard value is added to vibration detection part 20 for a predetermined number of times, vibration detection part 20 will break similarly. Therefore, it is possible to determine that the encoder 10 is in an abnormal state using the abnormality determination unit 30 not shown in FIG. 4 as described above.

  FIG. 5 is a partial perspective view of an encoder according to still another embodiment of the present invention. In FIG. 5, the housing 11 of the encoder 10 and the abnormality determination unit 30 are not shown for the sake of brevity. Such an abnormality determination unit 30 is assumed to be mounted on the housing 11 or the printed circuit board 12.

  As shown in FIG. 5, the vibration detection unit 20 includes a main body 21 and legs 28 and 29 that connect the main body 21 and the printed circuit board 12. Note that the bottom surface of the body 21 is not in contact with the printed circuit board 12. The main body 21 and the legs 28 and 29 of the vibration detection unit 20 are made of a conductive material. That is, in the embodiment shown in FIG. 5, the vibration detection unit 20 is attached only to the printed circuit board 12.

  In the embodiment shown in FIG. 5, when vibration is applied to the encoder 10, the printed circuit board 12 and the vibration detection unit 20 move relatively, and stress is generated in the vibration detection unit 20. And if the vibration more than a predetermined standard value is added to vibration detection part 20 for a predetermined number of times, vibration detection part 20 will break similarly. Therefore, it is possible to determine that the encoder 10 is in an abnormal state using the abnormality determination unit 30 not shown in FIG. 5 as described above. Therefore, it will be understood that the same effects as described above can be obtained in the embodiment shown in FIGS.

  FIG. 6 is a cross-sectional view of an encoder according to the second embodiment of the present invention. In FIG. 6, illustration of the printed circuit board 12 and the abnormality determination unit 30 of the encoder 10 is omitted for the sake of brevity. Such an abnormality determination unit 30 is assumed to be mounted on the housing 11 or the printed circuit board 12.

  As shown in FIG. 6, the vibration detection unit 20 is attached only to the housing 11 of the encoder 10. The vibration detection unit 20 includes a fixed portion 25 fixed to the housing 11 and a substantially L-shaped movable piece 23 having one end fixed to the housing 11. As can be seen from FIG. 6, the other end of the movable piece 23 is a free end 24 and is positioned above the fixed portion 25.

  FIG. 7 is a circuit diagram of the encoder shown in FIG. As can be seen from FIG. 7, the free end 24 of the vibration detection unit 20 is connected to a high potential portion of the printed circuit board 12, for example, a portion having a potential of 5 V, and the fixed portion 25 of the vibration detection unit 20 is connected to the printed circuit board 12. It is connected to a low potential portion, for example, a portion having a potential of 0V. The abnormality determination unit 30 including the comparator 31 is arranged in the same manner as described above. In this case, the comparator 31 compares the partial pressure at point A related to the vibration detection unit 20 with the reference potential E. When the potential at point A is small, a low level signal is output, and when the reference potential E is small, a high level signal is output.

  In the second embodiment, when vibration is applied to the encoder 10, the housing 11 and the vibration detection unit 20 move relatively. When a vibration exceeding a predetermined reference value occurs, the free end 24 vibrates in the vertical direction and comes into contact with the fixed portion 25.

  As a result, the potential at the point A becomes larger than the reference potential E, so that the output from the comparator 31 becomes a high level signal. As a result, the notification unit 40 is activated and notifies the user that the encoder 10 is in an abnormal state (in the second embodiment, the free end 24 of the vibration detection unit 20 has contacted the fixed unit 25). It will be apparent that the same effect as described above can be obtained even in such a case.

  FIG. 8 is a partial perspective view of an encoder according to the third embodiment of the present invention. In FIG. 8, three vibration detection units 20 a, 20 b, and 20 c are arranged on the printed circuit board 12. In FIG. 8, the illustration of the housing 11 and the abnormality determination unit 30 of the encoder 10 is omitted for the sake of brevity.

  Each of the vibration detection units 20a, 20b, and 20c shown in FIG. 8 includes a main body 21a, 21b, and 21c, and leg portions 28a, 29a, 28b, 29b, 28c, and 29c, like the vibration detection unit 20 of FIG. It is composed of The contact area of the legs 28b and 29b with the printed circuit board 12 is larger than the contact area of the legs 28a and 29a with the printed circuit board 12, and smaller than the contact area of the legs 28c and 29c with the printed circuit board 12. And Furthermore, in FIG. 8, it is assumed that three abnormality determination units 30a, 30b, and 30c corresponding to the three vibration detection units 20a, 20b, and 20c are mounted on the housing 11 or the printed circuit board 12.

  In the embodiment shown in FIG. 8, when vibration is applied to the encoder 10, the abnormality determination unit 30a related to the vibration detection unit 20a first determines abnormality. When a larger vibration is applied to the encoder 10, the abnormality determination unit 30b related to the vibration detection unit 20b determines the abnormality, and when a larger vibration is applied to the encoder 10, an abnormality determination related to the vibration detection unit 20c. The unit 30c determines abnormality.

  The notification unit 40 not shown in FIG. 8 issues a signal corresponding to each abnormality determination unit 30a, 30b, 30c every time the abnormality determination unit 30a, 30b, 30c determines abnormality. That is, the content of notification from the notification unit 40 can be made different according to each of the abnormality determination units 30a, 30b, and 30c, such as caution, warning, and emergency. Therefore, in the embodiment shown in FIG. 8, the user can take measures according to the urgency of the signal issued by the notification unit 40.

DESCRIPTION OF SYMBOLS 10 Encoder 11 Housing 11a, 11b Concave part 12 Printed circuit board 15 Electronic component 16 Fixture 20, 20a, 20b, 20c Vibration detection part 21, 21a, 21b, 21c Main body 23 Movable piece 24 Free end 25 Fixed part 28a, 29a, 28b 29b, 28c, 29c Leg 30, 30a, 30b, 30c Abnormality determination unit 31 Comparator 40 Notification unit

Claims (5)

In an encoder having a printed circuit board attached to a housing,
A vibration detection unit including a component whose conduction state changes when vibration of a predetermined reference value or more is applied, the vibration detection unit including the housing, the printed circuit board, and the housing and the printed circuit board; Installed in at least one of the
further,
An encoder comprising an abnormality determination unit that determines an abnormal state based on a change in a conduction state of a component included in the vibration detection unit.   2. The encoder according to claim 1, wherein the component included in the vibration detection unit is a component that is broken by fatigue failure to be in a non-conducting state when vibration exceeding the predetermined reference value is applied. The component included in the vibration detection unit is formed of two components in a non-contact state with each other,
2. The encoder according to claim 1, wherein the components are components that are brought into contact with each other and are brought into a conductive state when vibrations greater than the predetermined reference value are applied.   The encoder according to claim 1, further comprising a notification unit that notifies an abnormal state when the abnormal state is determined by the abnormality determination unit. A plurality of vibration detection units and a plurality of the abnormality determination units corresponding to each of the plurality of vibration detection units,
The encoder according to claim 4, wherein the reference values of components included in the plurality of vibration detection units are different from each other.

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