JP2009054940A - Pressure resistant explosion-proof case for information terminal, and method of forming window thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely fix the window member of a window which performs a communication with the outside of the terminal in a portable information terminal capable of transmitting and receiving information to/from the outside in an explosion-proof atmosphere. <P>SOLUTION: A stepped through-hole 76 is formed on the second case member 28 of the information terminal 22. A groove 92 for a resin is provided on a shoulder surface 78 which is the boundary of the large diameter part 74 and small diameter part 76 of the stepped through-hole. After a resin material is injected to the groove for the resin and turned to a half-solidified state, the window member 80 is mounted on the shoulder surface 78. Further, the resin material is injected to the gap of the second case member 28 and the window member 80 and is cured. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a case of an information terminal used in an environment where an explosive atmosphere may be formed such as a chemical plant, and more particularly to a structure of a window for transmitting light and a method of forming the window.

  Equipment used in an environment where an explosive atmosphere may be formed, such as a factory or a chemical plant, is required to adopt a structure that conforms to the electrical machinery / equipment explosion-proof structure standard. Explosion-proof structural standards include flameproof explosion-proof and intrinsically safe explosion-proof, and technical requirements are stipulated for each. An installation type electric machine apparatus used in a factory or the like, for example, a pump integrated with an electric motor does not need to be considered for portability, and thus can adopt a pressure-proof explosion-proof structure that increases weight and the like.

  A system for exchanging information with a stationary device by wireless communication has been put into practical use. For example, in Patent Document 1 below, in a system for monitoring the wear of a motor bearing, adjustment of a sensor for detecting wear and transmission / reception of information such as the detected degree of wear are performed by wireless communication using infrared rays. Technology is disclosed. In this document, a personal computer is exemplified as a device that exchanges information with an installed device. It is difficult to make the computer an explosion-proof structure, and when the equipment such as the pump is installed in an installation place where an explosion-proof structure standard is required, it is difficult to bring the computer directly into the installation place. In addition, for example, Japanese Patent Application Laid-Open Publication No. 2004-259542 describes that information is exchanged using a portable information terminal such as a PDA (Personal Digital Assistance).

Japanese Patent Laid-Open No. 2000-308312 JP 2005-276045 A

  When the information terminal as described above is used in an explosive atmosphere, it is desired to adopt an intrinsically safe explosion-proof structure in which the device does not trigger an explosion. However, in the case of the intrinsically safe explosion-proof structure, since the current value flowing through the device is limited, it has to be a small device or a device in which the circuit configuration is examined in detail. For example, it has been difficult for a general infrared remote controller driven by a 9V dry battery to have an intrinsically safe explosion-proof structure.

  An object of the present invention is to provide an information terminal having a pressure-proof explosion-proof structure.

  By making the case of an information terminal that transmits and receives information using optical communication such as infrared communication have a pressure-proof explosion-proof structure, the information terminal can be used in an explosive atmosphere. In order to perform optical communication, the case is provided with a window. The window is formed by fixing a window member made of a material that transmits light used for communication to a case member that forms a space therein. The case member has a stepped through hole that penetrates the inside and outside of the case member and includes a large diameter portion and a small diameter portion. The window member is disposed in the large-diameter portion of the through hole, and is fixed in contact with a shoulder surface that is a boundary between the large-diameter portion and the small-diameter portion. On the shoulder surface that is the boundary between the large-diameter portion and the small-diameter portion, an annular groove that is at least partially opposed to the surface that contacts the shoulder surface of the window member is provided. The annular groove is filled with a resin material. Further, a resin material is also filled in the gap between the large diameter portion of the through hole and the window member. The window member is fixed to the case member by these resin materials. This method of fixing the window can also be applied to a window provided for viewing a display device such as an LED (light emitting diode) provided in the case in order to check the operation status of the information terminal.

  The large-diameter portion of the through hole and the gap between the window member and the annular groove can communicate with each other. In this case, the resin material filled in the gap and the annular groove is integrated.

  The window of the above information terminal case can be formed as follows. That is, a stepped through hole including a large diameter portion and a small diameter portion is formed in the case member, an annular groove is formed on a shoulder surface that is a boundary between the large diameter portion and the small diameter portion of the through hole, and a resin material is formed in the annular groove. The window member is placed on the shoulder surface of the through hole, and the gap between the window member and the through hole is filled with a resin material. When forming the annular groove, the annular groove is formed so that the resin injected into the annular groove comes into contact with the window member when the window member is placed on the shoulder surface.

  Further, when forming the annular groove, the annular groove may be formed such that when the window member is placed on the shoulder surface, the gap between the window member and the through hole and the annular groove communicate with each other. .

  In addition, before the window member is placed on the shoulder surface of the through hole, a resin material may be applied to the surface of the window member facing the inner peripheral surface of the through hole large diameter portion in advance.

  Further, when the resin material is injected into the gap between the window member and the through hole, a pressing force may be applied to the window member toward the shoulder surface.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As a device used in a chemical plant, for example, there is a canned motor pump. FIG. 1 is a perspective view showing a schematic configuration of the canned motor pump. In the canned motor pump 10, a centrifugal pump 12 and an electric motor 14 are integrally formed. At the end of the electric motor 14 opposite to the side where the centrifugal pump is provided, there is provided a terminal box 16 that accommodates a coil in the electric motor 14 and a terminal for connecting a power line from the outside. Yes. A motor monitoring device 18 for monitoring the state of the electric motor 14 is disposed on the upper portion of the terminal box 16. The motor monitoring device 18 can monitor, for example, the wear state of a bearing that supports the shaft of the electric motor 14. A display unit 20 is provided at the top of the motor monitoring device 18 to display the status of monitoring target items such as the bearing wear status.

  Further, the motor monitoring device 18 is provided with a storage unit for storing information about a predetermined monitoring target item for a certain period, and further provided with an optical communication device for sending the stored information to the outside. Yes. The optical communication device is, for example, an infrared communication device.

  A portable information terminal 22 is used to read the information stored in the motor monitoring device 18 and transport this information to another location. The information terminal 22 has an optical communication device for transmitting and receiving information to and from the optical communication device of the motor monitoring device 18, and stores information read from the motor monitoring device 18 and information to be sent to the motor monitoring device 18. A storage unit. Information read from the motor monitoring device 18 and stored in the information terminal 22 is transported by moving the information terminal 22 to a location away from the motor installation location, and transferred there to another information processing device such as a computer. . Thereby, it becomes possible to analyze the operating condition of the canned motor pump 10 in another place.

  When the device to be monitored, in this case, the place where the canned motor pump 10 is installed is an environment where an explosive atmosphere may be formed, the information terminal 22 is made a flameproof construction, It becomes possible to easily monitor and analyze the operation status of the motor pump 10.

  FIG. 2 is a cross-sectional view of the information terminal 22. The information terminal 22 has a case 24 having a pressure-proof explosion-proof structure in which a space for accommodating a circuit board or the like is formed. The case 24 includes a substantially cylindrical first case member 26 having one end opened, a second case member 28 disposed so as to close the open end of the first case member, and the second case member as the first case member. It has a tightening ring 30 for tightening. The first and second case members 26 and 28 and the tightening ring 30 are made of an aluminum alloy, for example, A2017. By forming with the aluminum alloy, when the information terminal 22 is dropped, the occurrence of a spark due to an impact with another metal is suppressed. Further, by adopting A2017, it is possible to prevent damage to the main body due to chips during cutting.

  The first case member 26 includes a substantially disc-shaped end surface portion 32 and a substantially cylindrical cylindrical portion 34. The second case member 28 has a substantially disc-shaped end surface portion 36 that closes the open end of the first case member 26, and a cylindrical portion 38 that fits inside the cylindrical portion 34 of the first case member. . The end surface portion 36 has a flange portion 40 projecting outward from the outer periphery of the cylindrical portion 38, and the flange portion is in contact with the end surface of the cylindrical portion 34 of the first case member. A groove in which the O-ring 42 is accommodated is formed in the outer peripheral portion of the. The gap formed by the two cylindrical portions 34 and 38, that is, the so-called length and width of the ski are determined by the explosion-proof structure standard. A positioning pin 44 is driven into the end surface of the cylindrical portion 34 of the first case member, and a positioning groove 46 for receiving this pin is formed in the flange portion 40 of the second case member. By the engagement of the positioning pin 44 and the positioning groove 46, a light emitting element and a light receiving element related to optical communication, which will be described later, and a position of a window provided in the second case member 28 are aligned.

  The tightening ring 30 has an inner flange portion 50 projecting inside the cylinder at one end of a cylindrical portion 48 having a cylindrical shape. A female screw 52 is formed on the inner periphery of the cylindrical portion 48 and is coupled to a male screw 54 formed on the outer periphery of the cylindrical portion 34 of the first case member. These screws are metric screws, and their dimensions are strong enough to meet explosion-proof structural standards. The inner flange portion 50 is engaged with the flange portion 40 of the second case element member, and the second case member 28 is pushed toward the first case member 26 by screwing the tightening ring 30. At this time, the positioning pin 44 and the positioning groove 46 are engaged to function as a detent, and the second case member 28 is prevented from rotating with respect to the first case member 26. Further, the cylindrical portion 34 of the tightening ring 30 is provided with a non-rotating screw 56, and by tightening this screw, the tip thereof comes into contact with the first case member 26, and the first case member 26 is tightened. The loosening of the screw connection of the fitting ring 30 is prevented. The outer surface of the end surface portion 36 of the second case member is recessed from the end surface of the inner flange portion 50 of the tightening ring 30 and the lower surface in the figure, and the shape of this unevenness is the display portion of the motor monitoring device 18. Engage with the 20 convex shapes to prevent the entry of light from the outside.

  In the internal space of the case 24, an optical communication board 58 on which circuit components related to optical communication are mounted, a central processing unit that controls transmission and reception of information, and a CPU board 60 on which a memory for storing information and the like are mounted are arranged. . These substrates 58 and 60 are fixed to a fixing column 62 erected on the end surface portion 32 of the first case member. On the surface of the optical communication board 58 on the second case member 28 side, a light receiving element 64 and a light emitting element 66 related to optical communication are arranged. In addition, an LED 68 that indicates an operation state of the information terminal by a lighting state is disposed on a surface of the CPU case 60 on the end surface portion 36 side of the first case member.

  A communication window 70 is formed at a position of the end surface portion 36 of the second case member facing the light receiving element 64 and the light emitting element 66. This window is transparent to light rays for communication, for example, infrared rays in infrared communication, and enables transmission and reception of information by optical communication inside and outside the case. Further, a confirmation window 72 for confirming the operation status of the communication terminal 22 is also formed at a position of the end surface portion 32 of the first case member facing the LED 68. The communication window 70 and the confirmation window 72 have the same structure. In the following description, only the communication window 70 will be referred to, and the description of the confirmation window 72 will be omitted.

  A stepped through hole 76 having a large diameter portion 74 having a large diameter and a small diameter portion 75 having a small diameter is formed at a position where the communication window 70 is provided on the end surface portion 36 of the second case member. The window member 80 is placed on a surface formed in a shoulder surface 78 that is a boundary between the large diameter portion 74 and the small diameter portion 75, that is, a surface that intersects the axis of the stepped through hole 76 (an orthogonal surface in this embodiment). The The resin material 82 is filled between the second case member 28 and the window member 80, whereby the window member 80 is fixed to the second case member 28. Further, the window member 80 is supported by a pressing plate 86 fixed to the second case member by a screw 84 via a gasket 83. As shown in the figure, in this embodiment, the large diameter portion 74 of the stepped through hole 76 is located inside the case 24 and the small diameter portion 75 is located outside. The window member 80 is made of a material that can transmit light of interest. In the information terminal 22, general glass is used. In addition, since infrared rays have high straightness, when using infrared rays for communication, ground glass or the like can be used so that the infrared rays are scattered and the communication range is expanded.

  The aforementioned shoulder surface 78 is provided with an annular O-ring groove 90 surrounding the small-diameter portion 75 in which the O-ring 88 is accommodated. Further, an annular groove 92 surrounding the small diameter portion 75 is provided outside the O-ring groove 90. The groove 92 is filled with a resin material for fixing the window member 80, and the groove 92 is hereinafter referred to as a resin groove 92. The resin groove 92 faces a part of the surface that contacts the shoulder surface of the window member 80, and the resin filled in the groove is in contact with this surface of the window member 80. By this portion, the area of the resin material in contact with the window member 80 is increased, and the fixing force is increased. Further, when a force in the axial direction of the stepped through hole 76 acts, a tensile or compressive stress acts on the resin material in the groove, and a gap between the outer peripheral surface of the window member 80 and the inner peripheral surface of the large diameter portion 74 is affected. The window member 80 can be firmly fixed as compared with the case where the force is received only by the shear stress acting on the resin material. In this embodiment, the outer diameter of the resin groove 92 matches the diameter of the large diameter portion 74. Thus, even when the window member 80 is placed on the shoulder surface, the gap between the outer peripheral surface of the window member and the inner peripheral surface of the large diameter portion and the resin groove communicate with each other, and the resin material that fills these portions is integrated. .

  FIG. 3 is a diagram illustrating a process for forming the window 70. FIG. 3A shows a process of forming the stepped through hole 76 and the O-ring groove 90 and the resin groove 92 on the shoulder surface 78 thereof. This is performed by a general cutting process. When the grooves 90 and 92 are formed in the shoulder surface 78, the O-ring 88 is accommodated in the O-ring groove 90, and the resin material is injected into the resin groove 92 (FIG. 3B). As the resin material, flame retardant silicone or the like in which two liquid agents are mixed and cured can be used. The resin material to be injected into the resin groove 92 fills the groove or is injected in a slightly larger amount. This state is maintained, and the resin material 94 injected into the resin groove 92 is set to a semi-solidified state in which some fluidity remains.

  On the other hand, the same resin material as the resin material injected into the resin groove 92 is formed on the side surface of the window member 80, that is, when the window member 80 is accommodated in the stepped through hole 76. Apply (FIG. 3 (c)). The applied resin material 96 is shown with an emphasis on the thickness, and actually, it is applied much thinner than shown. The applied resin material 96 improves wettability so that the injected resin material comes into close contact with the window member 80 in the step of injecting the resin material into the gap between the window member 80 and the stepped through hole, which will be described later. Note that this step can be omitted when the combination of the window member 80 and the resin material has good wettability.

  As shown in FIG. 3D, the window member 80 with the resin material applied to the side surface is inserted into the large diameter portion 74 of the stepped through hole and placed on the shoulder surface 78. At this time, the semi-solidified resin material 94 and the lower surface of the window member 80 are in close contact with each other. It is desirable that the closely contacted portion is formed in an annular shape without interruption. The resin material 94 remains fluid, and the excess is pushed out into the gap between the window member 80 and the second case member 28. A pressing force may be applied to the shoulder surface 78 so that the window member 80 is in close contact with the shoulder surface 78. In brief, the pressing force can be generated by placing the weight 98 on the window member 80. A means such as a clamp may be used. If the weight of the window member 80 is sufficient, these additional pressing forces are unnecessary. The resin material is injected into the gap between the window member 80 and the second case member 28 in a state where the window member 80 is placed on the shoulder surface 78 and a pressing force is applied (arrow A). The injected resin material is blocked by the semi-solidified resin material 94 in the resin groove 92 and enters the gap between the shoulder surface 78 and the window member 80 and is prevented from leaking to the small diameter portion 75. Further, as described above, since the resin material is preliminarily applied to the side surface of the window member 80, it is possible to prevent bubbles from remaining on the side surface and to improve the adhesion.

  The resin material is filled in the gap between the window member 80 and the second case member 28 and maintained for a predetermined time to cure the resin material. The resin material injected later is integrated and cured with the resin material 94 previously semi-solidified and the resin material 96 attached to the noodles of the window member 80, and the window member 80 is fixed to the second case member 28. Resin material 82 is obtained.

  As the resin material, for example, DOW CORNING (registered trademark) SE 1816 CV KIT manufactured by Toray Dow Corning Co., Ltd. can be used. In this case, the time for the semi-solidified state is about 10 to 20 minutes, and the time for complete curing is about one day.

It is a perspective view which shows schematic structure of the canned motor pump with a motor monitoring apparatus. It is sectional drawing of an information terminal. It is explanatory drawing of the formation method of the window of an information terminal.

Explanation of symbols

  18 motor monitoring device, 22 information terminal, 24 case, 26 first case member, 28 second case member, 30 tightening ring, 70 communication window, 72 confirmation window, 74 large diameter portion, 75 small diameter portion, 76 Stepped through hole, 78 shoulder surface, 80 window member, 82 resin material, 92 resin groove, 98 weight.

Claims (8)

In a pressure-proof explosion-proof case of an information terminal that transmits and receives information by optical communication, a method of forming a window that transmits light,
Forming a stepped through hole including a large-diameter portion and a small-diameter portion in a case member of the explosion-proof case; and
Forming an annular groove on a shoulder surface that is a boundary between a large diameter portion and a small diameter portion of the through hole;
Injecting a resin material into the annular groove, and further making it a semi-solidified state,
After the resin material injected into the annular groove is semi-solidified, a step of placing a window member made of a material through which the target light is transmitted on the shoulder surface of the through hole;
Filling a gap between the window member and the through hole with a resin material;
Including
In the step of forming the annular groove, the annular groove is formed so that the resin injected into the annular groove comes into contact with the window member when the window member is placed on the shoulder surface.
Window forming method for explosion-proof case for information terminal. It is a window formation method of the explosion-proof case for information terminals according to claim 1,
In the step of forming the annular groove, when the window member is placed on the shoulder surface, the annular groove is formed so that the gap between the window member and the through hole communicates with the annular groove.
Method. A method of forming a window for an explosion-proof case for an information terminal according to claim 1 or 2,
Before the step of placing the window member on the shoulder surface of the through-hole, including a step of applying a resin material to the surface of the window member facing the inner peripheral surface of the through-hole large-diameter portion,
Method. It is the window formation method of the explosion-proof case for information terminals of any one of Claims 1-3,
In the step of filling the resin material in the gap between the window member and the through hole, a pressing force is applied to the window member toward the shoulder surface.
Method.   The method for forming a window for an explosion-proof case for an information terminal according to any one of claims 1 to 4, wherein the window is a window that transmits light for communication of information. An information terminal that transmits and receives information by optical communication, is a flameproof explosion-proof case having a window that transmits light,
A case member that forms a space inside, a case member that penetrates the inside and outside of the case member and has a stepped through hole including a large diameter portion and a small diameter portion,
A window member that is disposed within the large-diameter portion of the through-hole and contacts a shoulder surface that is a boundary between the large-diameter portion and the small-diameter portion, and transmits a communication light beam;
Including
The shoulder surface of the through hole has an annular groove that at least partially faces a surface that contacts the shoulder surface of the window member;
The gap between the large diameter portion of the through hole and the window member, and the annular groove are filled with a resin material for holding the window member.
Explosion-proof case for information terminals.   The explosion-proof case for information terminals according to claim 6, wherein the large-diameter portion of the through hole and the gap between the window member and the annular groove communicate with each other.   The explosion-proof case for information terminals according to claim 6 or 7, wherein the window is a window that transmits light for information communication.

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