JP2022139130A - Electronic apparatus - Google Patents

Abstract

To provide an electronic apparatus that is excellent in a heat dissipation property and also excellent in price competitiveness.SOLUTION: An electronic apparatus 1 is fixed to a rail for apparatus attachment 9. The electronic apparatus 1 comprises a circuit board 3 on which heating components 33 are mounted and a resin housing 2 that accommodates the circuit board 3. The resin housing 2 is composed of a first member 10 that is obtained by integrally molding a bottom wall part 11 provided with a locking pawl 13 engageable with the rail for apparatus attachment 9 and a column part 12 erected from the bottom wall part 11 and to which the circuit board 3 is fixed, and a second member 20 that is fixed to the bottom wall part 11 and accommodates the circuit board 3 in a closed space partitioned by the bottom wall part 11 and the second member. The first member 10 is formed of a resin material having higher thermal conductivity than that of the second member 20.SELECTED DRAWING: Figure 4

Description

The present invention relates to an electronic device fixed to a device mounting rail.

Electronic devices such as sensor controllers of FA sensors and programmable logic controllers used in FA (factory automation) are used by being fixed to metal rails called DIN rails. Such electronic equipment uses a metal heat-conducting plate as a heat-dissipating member for dissipating heat generated from heat-generating components in the housing to equipment-mounting rails (see, for example, Patent Document 1).

JP-A-9-162574

If metal materials, which are more expensive than resin materials, are used extensively for heat dissipation, the electronic equipment becomes expensive. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an electronic device that is excellent in heat dissipation and also excellent in price competitiveness.

An electronic device according to one aspect of the present disclosure is fixed to a device mounting rail. An electronic device includes a circuit board on which heat-generating components are mounted, and a resin housing that accommodates the circuit board. The resin housing is integrally formed with a bottom wall provided with locking claws that can be engaged with the equipment mounting rail, and a pillar standing up from the bottom wall and having the circuit board fixed thereto. It is composed of a first member and a second member that is fixed to the bottom wall and accommodates the circuit board in a closed space defined between the bottom wall and the bottom wall. The first member is made of a resin material having higher thermal conductivity than the second member.

According to this aspect, in the first member, the column portion for fixing the circuit board on which the heat-generating component is mounted is formed integrally with the bottom wall portion that engages with the device mounting rail. By using the first member, which has higher thermal conductivity than the second member, as a heat radiating member, the heat of the heat-generating component can be efficiently released to the equipment mounting rail. A plurality of electronic devices (control devices) are often fixed side by side on the device mounting rail. Since the second member has a lower thermal conductivity than the first member, the heat of the heat-generating component is transferred preferentially to the device mounting rail rather than to other adjacent electronic devices. Heat generation is less likely to adversely affect other electronic devices. Since the heat dissipation member is made of a resin material that is cheaper than a metal material, the manufacturing cost can be suppressed. Injection molding of resin materials is easier to process into complex shapes than press processing of metal materials, so manufacturing costs can be kept down by reducing the number of heat-dissipating sheets that fill the gaps between heat-generating components and heat-dissipating members. Since the resin housing can be sealed using ultrasonic welding or the like, which cannot be selected for joining metal materials and resin materials, the manufacturability is excellent.

In the above aspect, the columnar portion is formed in a flat plate shape having a first main surface and a second main surface opposite to the first main surface, and the mounting surface of the circuit board on which the heat-generating component is mounted is , may be arranged so as to face either one of the first main surface and the second main surface.

According to this aspect, since the pillars constituting the heat radiating member can ensure a wide heat radiation area with respect to the circuit board, heat can be efficiently released to the device mounting rail through the pillars.

In the above aspect, at least one of the first main surface and the second main surface may have a larger area than the mounting surface.

According to this aspect, since the areas of the first main surface and the second main surface facing the mounting surface are large, it is easy for the pillars to secure a large heat dissipation area with respect to the circuit board.

The above aspect may further include a connector that can be connected to an external device, a through hole penetrating through the first main surface and the second main surface may be formed in the column portion, and the connector may be inserted through the through hole.

According to this aspect, even if the closed space in the resin housing is narrowed by being divided by the column, a connector larger than the size after division can be arranged in the resin housing.

In the above aspect, the resin housing may have a closed structure.

A case with a sealed structure is characterized by the fact that it is difficult for dust to enter inside, but on the other hand, it tends to trap heat inside. It was difficult to select a sealed structure when constructing the housing only from resin materials that dissipate less heat than metal materials. According to this aspect, even a resin housing can dissipate heat more efficiently than a conventional product, so a closed structure can be selected even for a resin housing. Since both the first member and the second member are made of a resin material, the resin casing can be sealed using ultrasonic welding or the like. Excellent cost and manufacturability.

In the above aspect, the electronic device may be an amplifier unit of an amplifier-separated sensor.

Since the amplifier unit of the amplifier-separated sensor is connected to the sensing sensor by wire, it cannot be installed in a location that is too far from the detection target. A closed structure is preferable in order to prevent contamination by the detection target. This aspect is suitable for an amplifier unit of an amplifier-separated sensor because a sealed structure can be selected even with a resin housing.

In the above aspect, the electronic device includes a main unit in which a light emitting element, a light receiving element, and a detection circuit are housed in a resin housing, a sensor head for irradiating and receiving light on an object, the main unit and the sensor head. and a fiber connection portion for connecting the fiber to the light emitting element and the light receiving element.

A fiber sensor cannot be installed at a location that is too far away from a detection target due to limitations on the length of the fiber. A closed structure is preferable in order to prevent contamination by the detection target. This aspect is suitable for a fiber sensor because a sealed structure can be selected even with a resin housing.

In the above aspect, the first member and the second member may be formed from the same base resin material.

According to this aspect, by arranging the base material of the resin material forming the first member and the base material of the resin material forming the second member, the base materials have the same melting point and chemical affinity. Therefore, when the first member and the second member are fixed by means of welding, bonding, or the like, the joint surfaces can be firmly fixed.

In the above aspect, the second member may be formed from a polybutylene terephthalate resin containing an inorganic filler, and the first member may be formed from a polybutylene terephthalate resin containing a different type of inorganic filler than the second member. good.

According to this aspect, the first member can be formed from a resin material having a large difference in thermal conductivity from that of the second member. Since the base materials of the first member and the second member are the same, when the first member and the second member are fixed by means of welding or bonding, the joining surfaces can be firmly fixed.

In the above aspect, the thermal conductivity of the first member may be twice or more the thermal conductivity of the second member. The thermal conductivity of the first member may be 0.9 W/m·K or more.

According to this aspect, the heat of the heat-generating component can be efficiently released to the equipment mounting rail by using the first member having a sufficiently high thermal conductivity as the heat-dissipating member.

ADVANTAGE OF THE INVENTION According to this invention, the electronic device excellent in heat dissipation and excellent in price competitiveness can be provided.

FIG. 1 is a partially transparent perspective view showing an electronic device according to one embodiment of the present invention. FIG. 2 is a side view of the electronic device shown in FIG. 1 as viewed from the direction in which the device mounting rail extends. FIG. 3 is a bottom view of the locking claw shown in FIG. 2 as viewed from the bottom side of the equipment mounting rail. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 5 is a perspective view showing the first member by removing the second member and the like from the electronic device shown in FIG. 1. FIG. 6 is a perspective view showing the internal structure of the electronic device in the vicinity of the connector shown in FIG. 1. FIG.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that, in each figure, the same reference numerals have the same or similar configurations. Hereinafter, each configuration will be described in detail with reference to the drawings. FIG. 1 is a partially transparent perspective view showing an electronic device according to one embodiment of the present invention. As shown in FIG. 1, the electronic device 1 is used while being fixed to the device mounting rail 9 . The device mounting rail 9 is, for example, a DIN rail, and has standardized dimensions and shapes defined in JIS C2812: 1998 in JIS (Japanese Industrial Standards) corresponding to DIN (German Industrial Standards). .

In the illustrated example, the electronic device 1 is configured as an amplifier unit for an amplifier-separated sensor, and includes a connector 5 (first connector 51) to which a sensor unit having a sensing function can be connected. The amplifier unit further includes a cable 6 connectable to an external power supply that supplies power, a connector 5 (second connector 52) connectable to an external device, etc., and amplifies the signal detected by the sensor unit and converted into an electrical signal. and send it to the external device.

However, the electronic device 1 is not limited to the amplifier unit of the amplifier-separated sensor. The electronic device 1 includes a main body in which a light emitting element that emits light, a light receiving element that receives light, a detection circuit that detects changes in both the light reaching the light receiving element and converts them into electric signals, etc., are housed in a resin housing 2. a unit, a sensor head for irradiating and receiving light on an object, a fiber for connecting the main unit and the sensor head, a fiber connection part for connecting the fiber to the light emitting element and the light receiving element, It may be a fiber sensor with Other types of FA sensors may be used. When the electronic device 1 is a fiber sensor, the first connector 51 is configured as a connector for connecting with a fiber.

The connector 5 and cable 6 described above are connected to the circuit board 3 (the first and second boards 31 and 32). The circuit board 3 includes an amplifier that amplifies the signal detected by the sensor unit and converted into an electric signal, a signal processor that processes the signal output from the amplifier, and a signal processor that transmits the output of the signal processor to an external device. A communication section, an amplifier section, a control section for controlling the communication section, and the like are mounted. These are composed of heat-generating components 33 such as IC chips.

The circuit board 3 is housed inside the resin housing 2 . The resin housing 2 can be divided in the vertical direction indicated by the Z axis in FIG. , consists of The resin housing 2 includes a substantially box-shaped bottom wall portion 11, a peripheral wall portion 21, and a top wall portion 22 that define a sealed closed space. The first member 10 constitutes the bottom wall portion 11 , and the second member 20 constitutes the peripheral wall portion 21 and the ceiling wall portion 22 .

The first member 10 further has a pillar portion 12 erected from the bottom wall portion 11 in addition to the bottom wall portion 11 described above. The column portion 12 is arranged within the closed space of the resin housing 2 . The circuit board 3 is fixed to the column portion 12 . The second member 20 further has a panel concave portion 23 provided outside the closed space of the resin housing 2 in addition to the peripheral wall portion 21 and the ceiling wall portion 22 described above. The operation panel 4 is placed in the panel recess 23 . The operation panel 4 includes an indicator for the user to visually check the operating state of the amplifier unit, operation buttons for the user to input operations, a substrate for controlling them, and the like.

FIG. 2 is a side view of the electronic device 1 shown in FIG. 1 along the X-axis, which is the extending direction of the device mounting rails. FIG. 3 is a bottom view of the locking claw 13 shown in FIG. As shown in FIG. 2, the aforementioned second connector 52 is sealed by an attached cover when not in use. As shown in FIGS. 2 and 3, the first member 10 has locking claws 13 that can be engaged with the equipment mounting rails 9 . By hooking the locking claw (first locking claw) 13 on the equipment mounting rail 9 and attaching the external locking claw (second locking claw) 19 to the first member 10, the electronic equipment 1 can be used for equipment mounting. It can be fixed to the rail 9.

FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. As shown in FIG. 4, FIG. 5 is a perspective view showing only the first member 10 with the second member 20 and the circuit board 3 removed from the electronic device 1 shown in FIG. As shown in FIG. 5, the column portion 12 has a first main surface (left side surface) 12A, a second main surface (right side surface) 12B opposite to the first main surface 12A, and first and second main surfaces 12B. and an end face connecting between the main surfaces 12A and 12B.

The first and second main surfaces 12A and 12B extend along the YZ plane orthogonal to the X-axis, which is the extending direction of the equipment mounting rail 9 . Since the first main surface 12A and the second main surface 12B of the column portion 12 have substantially the same shape and function, the first main surface 12A will be described in detail as a representative, and the second main surface will be described in detail. 12B will be omitted from redundant description.

As shown in FIG. 5, the post 12 includes a plurality of self-tapping screw bosses 14 provided on the first and second main surfaces 12A and 12B, and a plurality of self-tapping screw bosses 14 provided on the first and second main surfaces 12A and 12B. , and a protrusion 15 having the same protrusion height as the boss 14 . A through hole 12H is formed in the column portion 12 so as to penetrate through the first and second main surfaces 12A and 12B.

FIG. 6 is a perspective view showing the internal structure of the electronic device in the vicinity of the second connector 52 shown in FIG. As shown in FIG. 6, the second connector 52 has a prism shape extending from one end 52A to the other end 52B opposite to the one end 52A along the X-axis, which is the extending direction of the equipment mounting rail 9. A second connector 52 is inserted through a through hole 12</b>H formed in the column portion 12 . That is, the one end 52A protrudes from the first main surface 12A of the column portion 12, and the other end 52B protrudes from the second main surface 12B. The shape of the second connector 52 is not limited to the illustrated example, and may be cylindrical or other shapes.

The one end 52A and the other end 52B are provided with contact terminals for mechanical engagement and electrical connection with contact terminals of a connector of an external device. Openings are formed in the peripheral wall portion 21 of the resin housing 2 at positions corresponding to the one end 52A and the other end 52B. As described above, the opening of the peripheral wall portion 21 is closed by the attached cover except when it is used. In the illustrated example, the second connector 52 is directly fixed to the first circuit board 31 and passes through the mounting surface of the first circuit board. An opening is formed in the second circuit board 32 at a position corresponding to the other end 52B of the second connector 52 .

As shown in FIG. 4, the circuit board 3 is arranged so that the mounting surface on which the heat-generating component 33 is mounted faces the first main surface 12A, and is fixed to the boss 14 of the column portion 12 with a tightening screw 15. . The circuit board 3 may be fixed to the column portion 12 with the mounting surface facing the second main surface 12B. In the illustrated example, the circuit board 3 is divided into a first circuit board 31 and a second circuit board 32, which are fixed to the first and second main surfaces 12A and 12B of the column portion 12, respectively. As shown in FIG. 1 , the first main surface 12A is formed to have a larger area than the mounting surface of the first circuit board 31 . Similarly, although not shown, the second main surface 12B is formed to have a larger area than the mounting surface of the second circuit board 32 .

As shown in FIG. 4 , a heat dissipation sheet 34 is arranged in the gap between the heat generating component 33 and the column portion 12 . Adhesive heat radiation sheet 34 is adhered so as to fill the gap between column portion 12 and heat generating component 33 to improve thermal conductivity from heat generating component 33 to column portion 12 . The gap between the heat-generating component 33 and the column portion 12 may be filled with a heat-conducting paste or the like instead of the heat-dissipating sheet 34 .

The inside of the resin housing 2 is defined as a sealed closed space. Since both the first and second members 10 and 20 are made of resin material, the first and second members 20 can be joined using ultrasonic welding or the like. As shown in FIG. 4, the end surface 21E of the peripheral wall 21 of the second member 20 is in close contact with the inner surface 11A of the bottom wall portion 11 of the first member 10 without any gap.

As shown in FIG. 5, a bottom wall portion 11 provided with locking claws 13 engageable with the equipment mounting rail 9 and a column portion 12 to which the circuit board 3 is fixed are formed integrally. In the conventional product, for example, a metal column penetrates the resin bottom wall and extends to the device mounting rail 9, and the gap between the heat-generating component 33 and the side of the column and the lower end of the column and the device mounting rail 9 is filled with a heat radiation sheet 34.例文帳に追加Since it is not possible to form pillars having a very complicated shape by pressing a metal material, the heat dissipation sheet 34 had to be used more often than in the present embodiment. In contrast, according to the present embodiment, since the column portion 12 and the bottom wall portion 11 are integrally formed by injection molding of a resin material, heat dissipation required for the gap between the metal column portion and the device mounting rail 9 is reduced. The sheet 34 can be omitted. The gap between the heat-generating component 33 and the column portion 12 is also small. The usage amount of the heat dissipation sheet 34 can be reduced.

One of the characteristics of the electronic device 1 of the present embodiment is that the first member 10 is made of a resin material having a higher thermal conductivity than the second member 20 . The second member 20 is made of, for example, polybutylene terephthalate resin containing inorganic filler such as glass fiber. The first member 10 may be made of polybutylene terephthalate resin containing a different type of inorganic filler from the second member 20 . The inorganic filler having high thermal conductivity may be a metal oxide inorganic filler or a metal filler.

Alternatively, the fillers in the first and second members 10, 20 may be of the same type. In that case, the first member 10 should have a higher filler content than the second member 20 . The base material of the resin material of the first and second members 10 and 20 is not limited to polybutylene terephthalate resin. Polycarbonate resin, polyamide resin, or polyphenylene sulfide resin may be used. Various base materials can be selected as long as they are resin materials having excellent moldability, electrical properties, heat resistance, mechanical properties, and the like. If the base material of the resin material forming the first member 10 and the base material of the resin material forming the second member 20 are the same, the base materials have the same melting point and chemical affinity is improved. When the first member 10 and the second member 20 are fixed by means of welding, adhesion, or the like, the joint surface 21E (shown in FIG. 4) can be firmly fixed.

It is desirable that the thermal conductivity of the first member is at least twice the thermal conductivity of the second member. The thermal conductivity of the second member 20 is, for example, approximately 0.33 W/m·K. The thermal conductivity of the first member 10 is, for example, 0.5 to 10 W/m·K, preferably 0.9 W/m·K or more. The thermal conductivity of the first member and the second member can be measured, for example, by the measuring method specified in ISO 22007-2:2015.

According to the electronic device 1 of the present embodiment configured as described above, the column portion 12 for fixing the circuit board 3 on which the heat-generating component 33 is mounted and the bottom wall portion 11 for engaging the device mounting rail 9 are Since the heat-generating component 33 is integrally molded using a resin material with high thermal conductivity, the heat of the heat-generating component 33 can be efficiently released to the equipment mounting rail 9 . Since the heat dissipation member is made of a resin material such as polybutylene terephthalate resin, which is cheaper than a metal material, the manufacturing cost of the electronic device 1 can be suppressed. Since both the first and second members 10 and 20 are made of a resin material, the resin casing 2 can be sealed using ultrasonic welding or the like, which was not an option for joining a metal material and a resin material. can be done. Even if the resin housing 2 is used, a sealed structure that does not easily dissipate heat can be selected, so it is particularly suitable for an amplifier unit of an amplifier-separated sensor or a fiber sensor.

The embodiments described above are for facilitating understanding of the present invention, and are not intended to limit and interpret the present invention. Each element included in the embodiment and its arrangement, materials, conditions, shape, size, etc. are not limited to those illustrated and can be changed as appropriate. Also, it is possible to partially replace or combine the configurations shown in different embodiments.

[Note]
An electronic device (1) fixed to a device mounting rail (9),
a circuit board (3) on which a heat-generating component (33) is mounted;
A resin housing (2) that houses the circuit board (3),
The resin casing (2) is
A bottom wall portion (11) provided with locking claws (13) engageable with the equipment mounting rail (9), and a circuit board (3) standing from the bottom wall portion (11). a first member (10) integrally formed with a fixed column (12);
a second member (20) that is fixed to the bottom wall (11) and accommodates the circuit board (3) in a closed space defined between the bottom wall (11),
The first member (10) is made of a resin material having a higher thermal conductivity than the second member (20),
Electronics.

DESCRIPTION OF SYMBOLS 1... Electronic equipment 2... Resin housing 3... Circuit board 4... Operation panel 5... Connector 6... Cable 9... Equipment mounting rail 10... First member 11... Bottom wall part 11A... Inner surface 12 Column portion 12A First main surface 12B Second main surface 12H Through hole 13 Locking claw 14 Boss 15 Convex portion Second locking claw 19, 20 Second member 21 Peripheral wall portion 21E End surface 22 Top wall portion 23 Panel concave portion 31 First substrate 32 Second substrate 33 Heat-generating component 34 Heat dissipation sheet 35 Fastening Screw, 51...first connector, 52...second connector, 52A...one end, 52B...other end.

Claims (12)

An electronic device fixed to a device mounting rail,
a circuit board on which heat-generating components are mounted;
and a resin housing that houses the circuit board,
The resin casing is
A first member integrally formed with a bottom wall portion provided with locking claws engageable with the device mounting rail and a column portion standing from the bottom wall portion and having the circuit board fixed thereto. When,
a second member that is fixed to the bottom wall and accommodates the circuit board in a closed space defined between the bottom wall and the second member;
The first member is made of a resin material having a higher thermal conductivity than the second member,
Electronics. The pillar portion is formed in a flat plate shape having a first principal surface and a second principal surface opposite to the first principal surface,
The mounting surface of the circuit board on which the heat-generating component is mounted is arranged to face either one of the first main surface and the second main surface,
The electronic device according to claim 1. At least one of the first main surface and the second main surface has a larger area than the mounting surface,
The electronic device according to claim 2. It also has a connector that can be connected to an external device,
A through hole penetrating the first main surface and the second main surface is formed in the column portion, and the connector is inserted through the through hole,
The electronic device according to claim 2 or 3. The resin housing has a closed structure,
The electronic device according to any one of claims 1 to 4. The electronic device is an amplifier unit of an amplifier-separated sensor,
The electronic device according to any one of claims 1 to 5. The electronic device includes a main unit in which a light emitting element, a light receiving element, and a detection circuit are housed in the resin housing, a sensor head for irradiating and receiving light on an object, the main unit and the sensor head. and a fiber connection part for connecting the fiber to the light emitting element and the light receiving element,
The electronic device according to any one of claims 1 to 5. The joint surfaces of the first member and the second member are welded,
The electronic device according to any one of claims 1 to 7. The first member and the second member are formed from the same base resin material,
The electronic device according to claim 8. The second member is formed of a polybutylene terephthalate resin containing an inorganic filler,
The first member is formed of a polybutylene terephthalate resin containing a different type of inorganic filler from the second member,
The electronic device according to any one of claims 1 to 9. The thermal conductivity of the first member is at least twice the thermal conductivity of the second member,
The electronic device according to any one of claims 1 to 10. The first member has a thermal conductivity of 0.9 W/m K or more.
The electronic device according to any one of claims 1 to 11.

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