Control device

Abstract

Provided is a control device (10) comprising: a housing (20) that is formed in a box shape by combining metal flat plates, and comprises at least one opening (25); a door (30) that is attached to the housing (20), is able to open and close to block the opening (25), and is made of a metal material; a conductive cable (60) that electrically connects the housing (20) and the door (30); and a shield member (52) that has elasticity and conductivity, and is attached to either a housing-side peripheral edge (22f) provided along a peripheral edge of the opening (25) or a door-side peripheral edge (30f) provided on a position of the door (30) corresponding to the housing-side peripheral edge (22f), and in a state in which the door (30) is disposed in a closed position, the shield member (52) is in close contact with the housing-side peripheral edge (22f) and the door-side peripheral edge (30f).

Description

Control device

[0001] The present disclosure relates to a control device.

[0002] There is known a device in which a door packing for dustproofing and waterproofing the inside of a housing and an EMI packing for preventing the intrusion of electromagnetic waves into the housing are arranged between a box-shaped housing and a door that opens and closes an opening provided in the housing (see, for example, Patent Document 1). Arranging a conductive member such as an EMI packing between the housing and the door, as in this device, is generally performed as an EMC measure to prevent the leakage of electromagnetic waves from the inside of the housing to the outside and the intrusion of electromagnetic waves from the outside into the housing.

[0003] Japanese Patent Laid-Open No. 8-330777

[0004] However, as described above, simply arranging a conductive member in the gap between the housing and the door to prevent the leakage and intrusion of electromagnetic waves from that gap does not necessarily provide sufficient EMC measures. For example, due to the stray capacitance of the electronic components inside the housing, a noise voltage may be induced in the housing and the door, and a potential difference may occur between the two. Then, a noise current is generated due to this potential difference, which may cause a malfunction in the electronic components housed inside the housing.

[0005] Therefore, it is desired to be able to suppress the generation of noise current due to the potential difference between the housing and the door while preventing the leakage and intrusion of electromagnetic waves from the gap between the housing and the door.

[0006] One aspect of the present disclosure is a control device including a housing formed in a box shape by a combination of flat metal plates and having at least one opening, a door made of a metal material attached to the housing and closing the opening in an openable manner, a conductive cable electrically connecting the housing and the door, and an elastic and conductive shield member attached to either a housing-side peripheral portion provided along the periphery of the opening or a door-side peripheral portion provided at a position corresponding to the housing-side peripheral portion of the door. In a state where the door is disposed in a closed position, the shield member is in close contact with the housing-side peripheral portion and the door-side peripheral portion.

[0007] This is a perspective view showing the configuration of a control device according to one embodiment of the present disclosure. This is an enlarged view showing the housing and door of the control device shown in Figure 1. This is a partial cross-sectional view showing the door in the open position relative to the housing of the control device shown in Figure 1. This is a partial cross-sectional view showing the door in the closed position relative to the housing of the control device shown in Figure 1. This is a partial cross-sectional view showing the housing and door of a modified example of the control device shown in Figure 1.

[0008] A control device 10 according to one embodiment of the present disclosure will be described below with reference to the drawings. The control device 10 is a control device for controlling industrial machinery such as a robot (not shown). The control device 10 includes, for example, a housing 20, a door 30 attached to the housing 20, a waterproof packing 51 and a conductive packing (shielding member) 52 attached to the door 30, and a conductive cable 60, as shown in Figure 1.

[0009] The housing 20 is formed in a roughly rectangular box shape by combining flat plates made of metal such as steel. The surface of each plate constituting the housing 20 is painted with a non-conductive paint to protect it from rust and corrosion. The housing 20 also has a horizontally extending bottom surface 21 that allows the control device 10 to be installed on a mounting surface such as a floor, four side surfaces 22 that rise vertically upward from the periphery of the bottom surface 21, and a top surface 23 that faces the bottom surface 21. In other words, the housing 20 has a roughly rectangular internal space defined by the bottom surface 21, the top surface 23, and the four side surfaces 22 positioned between them. This internal space houses a control board and various electronic components for controlling industrial machinery such as robots, which are the objects of control.

[0010] Furthermore, on the front side of the four sides 22, an opening 25 is provided that connects the internal space of the housing 20 to the outside by opening the inner region, excluding the peripheral edge (housing-side peripheral edge) 22f. In addition, as shown in Figures 1 and 2, a flange-shaped protrusion 22c is formed on the peripheral edge 22f, extending forward around its entire circumference. That is, the protrusion 22c is formed in the shape of a roughly rectangular frame that protrudes forward from the peripheral edge 22f. In this embodiment, as shown in Figure 2, unpainted portions (conductive portions) E are formed at the tips of the portions corresponding to the four corners of the protrusion 22c, where the paint has been removed to expose the surface of the underlying metal plate material.

[0011] Furthermore, the bottom surface 21 also has a section where the paint has been partially removed to expose the underlying metal plate, and the housing 20 is connected to the ground by an earth wire (not shown) connected to this section.

[0012] The door 30 is a component for closing the opening 25 of the housing 20, and is a flat plate made of a metal material such as steel, with a size equivalent to the side surface 22 of the housing 20 on the opening 25 side. The surface of the door 30, like the housing 20, is painted with a non-conductive paint to protect it from rust and corrosion.

[0013] Furthermore, as shown in Figures 1 and 2, the door 30 is pivotably attached to the housing 20 via two hinges 40 attached to one edge of a pair of side surfaces 22 adjacent to the side surface 22 of the housing 20 on the side facing the opening 25. In other words, the door 30 is attached to the housing 20 so as to be able to open and close the opening 25. In addition, a locking mechanism (not shown) is provided on the edge of the opening 25 opposite to the hinges 40 to hold the door 30 in the closed position that closes the opening 25.

[0014] Furthermore, a waterproof packing 51 and a conductive packing 52, which will be described later, are attached to the inner peripheral edge (door-side peripheral edge) 30f of the door 30. In this case, the inner surface of the door 30 is the surface that faces the opening 25 of the housing 20 when the door 30 is in the closed position, and in that state, the peripheral edge 30f of the door 30 and the peripheral edge 22f of the housing 20 face each other.

[0015] The waterproof packing 51 is, for example, a member formed from a flexible elastic material such as rubber into a long cylindrical shape, as shown in Figure 3, and is arranged around the entire circumference along the outermost edge of the peripheral portion 30f. That is, when the door 30 is in the closed position, the waterproof packing 51 is pressed against the outermost edge of the peripheral portion 22f of the housing 20 and compressed in the thickness direction, as shown in Figure 4. As a result, the gap between the housing 20 and the door 30 when the door 30 is closed is sealed, preventing dust, liquids, etc. from entering the internal space inside the housing 20.

[0016] The conductive packing 52 is a component formed by wrapping and bonding a thin cloth plated with a metal such as nickel around the surface of a core material, which is, for example, a sponge made of polyurethane foam formed into a long rod shape. As shown in Figure 3, the conductive packing 52 is positioned in the area on the inner side of the peripheral edge 30f of the door 30, in accordance with the circumferential direction of the waterproof packing 51. That is, as shown in Figure 4, the conductive packing 52 is positioned at a location corresponding to the protrusion 22c of the housing 20 when the door 30 is in the closed position.

[0017] In this embodiment, the conductive packing 52 is attached by double-sided tape or the like to a surface that is one level lower than the surface on the peripheral edge 30f to which the waterproof packing 51 is attached. In this case, as shown in Figure 3, the surface to which the conductive packing 52 is attached is set at a height such that the conductive packing 52 protrudes slightly from the surface on the peripheral edge 30f to which the waterproof packing 51 is attached. As a result, as shown in Figure 4, when the door 30 is placed in the closed position, the tip of the protrusion 22c of the conductive packing 52 is pressed against it and compressed within a range that allows for elastic deformation.

[0018] As shown in Figure 1, the conductive cable 60 is, for example, a wire with crimp terminals 61 and 62 attached to both ends. One end of the crimp terminal 61 is fixed by screw to the inner surface of the side 22 to which the hinge 40 is attached. Similarly, the other end of the crimp terminal 62 is fixed by screw to the inner surface of the door 30. The paint has been removed from the connection points between the side 22 of the housing 20 and the inner surface of the door 30 to which the crimp terminals 61 and 62 are screwed. In other words, the crimp terminals 61 and 62 are in direct contact with the underlying metal plate material of the side 22 of the housing 20 and the inner surface of the door 30, respectively, so that the housing 20 and the door 30 are electrically connected via the conductive cable 60.

[0019] The operation of the control device 10 according to this embodiment, configured as described above, will be explained below. When the open door 30, as shown in Figure 3, is swung toward the opening 25 of the housing 20, the waterproof packing 51 attached to the peripheral edge 30f of the door 30 is pressed against the peripheral edge 22f of the housing 20, as shown in Figure 4. As a result, the gap between the housing 20 and the door 30 is sealed by the waterproof packing 51, preventing dust and liquids from entering the housing 20 and protecting the electronic components housed inside the housing 20.

[0020] Furthermore, since both the housing 20 and the door 30 are made of metal, when the door 30 is in the closed position, the electronic components housed inside the housing 20 are surrounded by various metal components. Therefore, a so-called electromagnetic shielding effect can be obtained, which suppresses the leakage of electromagnetic waves generated by the electronic components inside the housing 20 to the outside and the intrusion of electromagnetic waves from the outside into the housing 20.

[0021] Furthermore, in this embodiment, when the door 30 is in the closed position, the conductive packing 52 attached to the peripheral edge 30f of the door 30 is pressed against the tip of the protrusion 22c provided on the peripheral edge 22f of the housing 20. That is, the conductive packing 52 is in close contact with the tip of the protrusion 22c that protrudes in a frame shape from the peripheral edge 22f of the housing 20 over its entire circumference. Therefore, the conductive packing 52 is electrically conductive with the housing 20 through the unpainted portions E provided at the four corners of the protrusion 22c, while sealing the space between the housing 20 and the door 30 without any gaps. In other words, by filling the gap between the housing 20 and the door 30 with the conductive packing 52, which is electrically conductive with the housing 20, the electromagnetic shielding effect can be exerted more effectively.

[0022] Furthermore, if there is a potential difference between the enclosure 20 and the door 30, noise generated by the noise voltage induced by that potential difference is emitted to the outside and returns to the enclosure 20 via the ground, resulting in so-called common-mode noise. However, in this embodiment, since the enclosure 20 and the door 30 are electrically connected by a conductive cable 60, the potential difference between them can be made as small as possible. This also has the effect of minimizing common-mode noise.

[0023] Furthermore, in this embodiment, the unpainted portions E provided for electrically connecting the housing 20 and the conductive packing 52 are arranged only at the four corners of the protrusions 22c. This ensures electrical conductivity between the housing 20 and the conductive packing 52 while minimizing the area where the underlying metal plate material of the housing 20 is exposed. Therefore, the housing 20's resistance to rust and corrosion is not significantly impaired.

[0024] Furthermore, in this embodiment, since the unpainted portion E is provided at the tip of the protrusion 22c, the condition of the unpainted portion E can be visually checked when the door 30 is open. Therefore, there is also the advantage that the occurrence of rust or corrosion on the unpainted portion E can be easily detected.

[0025] In this embodiment, the unpainted portion E is set at the tip of the protrusion 22c of the housing 20. Alternatively, the unpainted portion E may be set as part of the area on the peripheral edge 30f of the door 30 to which the conductive packing 52 is attached. In this case, the double-sided tape used to attach the conductive packing 52 to the peripheral edge 30f should be cut out so that it does not cover the unpainted portion E. Alternatively, the conductive packing 52 can be fixed to the peripheral edge 30f with an adhesive or the like that does not hinder electrical conductivity between the door 30 and the conductive packing 52.

[0026] As a result, the gap between the housing 20 and the door 30 can be filled with a conductive packing 52 that is electrically connected to the door 30, and thus, as in the above embodiment, the electromagnetic shielding effect can be exerted more effectively.

[0027] Alternatively, the unpainted portion E may be provided on both a part of the tip of the protrusion 22c of the housing 20 and a part of the peripheral edge 30f of the door 30 to which the conductive packing 52 is attached. This ensures electrical conductivity between the housing 20 and the door 30 via the conductive packing 52.

[0028] Furthermore, in this embodiment, one unpainted section E is provided at each of the four corners of the protrusion 22c, but the number of unpainted sections E should be at least one. For example, if the number of unpainted sections E is increased within a range where rust and corrosion of the housing 20 is acceptable, and each is arranged at equal intervals in the circumferential direction, a more effective shielding effect can be obtained.

[0029] In this embodiment, the conductive packing 52 is attached to the inner surface of the door 30, but instead, the conductive packing 52 may be attached to the peripheral edge 22f of the housing 20.

[0030] In the example shown in Figure 5, the protrusion 22c on the peripheral edge 22f of the housing 20 in the above configuration is omitted, and a conductive packing 52 is attached to the resulting empty space. The peripheral edge 30f of the door 30 is provided with a flange-shaped protrusion 30c that extends all the way around, projecting toward the conductive packing 52. In this case, the amount of protrusion of the protrusion 30c should be such that it slightly pushes the conductive packing 52 when the door 30 is in the closed position, and an unpainted portion E should be provided at its tip. This will provide the same effect as described above.

[0031] Furthermore, in this embodiment, the conductive packing 52 was arranged around the entire circumference of the peripheral edge 30f of the door 30, but the conductive packing 52 does not necessarily have to be arranged around the entire circumference of the peripheral edge 30f. For example, in order to avoid interference with the internal space of the housing 20 and parts attached to the inner surface of the door 30, or with hinges 40 that attach the door 30 to the housing 20, a part of the conductive packing 52 in the circumferential direction may be cut out. In this case, by minimizing the size of the cutout in the conductive packing 52, the reduction in the electromagnetic shielding effect can be minimized.

[0032] Furthermore, in this embodiment, a conductive packing 52 is exemplified as a polyurethane foam sponge wrapped with conductive cloth, but the conductive packing 52 is not limited to this. The conductive packing 52 may be, for example, a finger gasket with a metal leaf spring structure, or an elastomer gasket made by mixing conductive particles into an elastomer such as rubber.

[0033] Although embodiments of this disclosure have been described in detail above, this disclosure is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of the invention or from the spirit and intent of the invention derived from the claims and their equivalents. For example, the order of operations and processes in the embodiments described above are shown as examples only and are not limited thereto.

[0034] With respect to the above embodiments and modifications, the following additional notes are disclosed. (Note 1) A control device comprising: a housing formed in a box shape by a combination of metal plates and having at least one opening; a door made of a metal material attached to the housing and closing the opening so as to be openable and closable; a conductive cable electrically connecting the housing and the door; and an elastic and conductive shielding member attached to either a housing-side peripheral edge provided along the periphery of the opening or a door-side peripheral edge provided at a position corresponding to the housing-side peripheral edge of the door, wherein when the door is in the closed position, the shielding member is in close contact with the housing-side peripheral edge and the door-side peripheral edge. (Note 2) The control device according to Note 1, wherein a convex portion projecting in a flange-like manner toward the other side is provided along the circumferential direction on either the housing-side peripheral edge or the door-side peripheral edge, and when the door is in the closed position, the tip of the convex portion is pressed against the shielding member. (Note 3) The control device according to Note 1 or Note 2, wherein at least one of the housing-side peripheral edge or the door-side peripheral edge is provided with a conductive portion that enables electrical connection with the shielding member when the door is in the closed position. (Note 4) The control device according to Note 3, wherein the housing-side peripheral edge and the door-side peripheral edge are each formed in the shape of a rectangular frame, and the conductive portions are arranged at the four corners of at least one of the housing-side peripheral edge or the door-side peripheral edge.

[0035] 10 Control device 20 Housing 22c Protrusion 22f Peripheral part (housing side periphery) 25 Opening 30 Door 30f Peripheral part (door side periphery) 52 Conductive packing (shielding member) 60 Conductive cable E Unpainted part (conductive part)

Claims

1. A control device comprising: a housing formed in a box shape by a combination of metal plates and having at least one opening; a door made of a metal material attached to the housing and closing the opening so as to be openable and closable; a conductive cable electrically connecting the housing and the door; and an elastic and conductive shielding member attached to either a housing-side peripheral edge provided along the periphery of the opening or a door-side peripheral edge provided at a position corresponding to the housing-side peripheral edge of the door, wherein when the door is in the closed position, the shielding member is in close contact with the housing-side peripheral edge and the door-side peripheral edge.

2. The control device according to claim 1, wherein a projection is provided along the circumferential direction on either the peripheral edge of the housing side or the peripheral edge of the door side, which is either one of the two, and which protrudes in a flange-like manner toward the other side, and when the door is in the closed position, the tip of the projection is pressed against the shield member.

3. The control device according to claim 1 or 2, wherein at least one of the peripheral edge on the housing side or the peripheral edge on the door side is provided with a conductive portion that enables electrical connection with the shielding member when the door is in the closed position.

4. The control device according to claim 3, wherein the housing-side peripheral edge and the door-side peripheral edge are each formed in the shape of a rectangular frame, and the conductive portion is arranged at at least one of the four corners of the housing-side peripheral edge or the door-side peripheral edge.

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