JP2011007200A - Cooling device for air compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently cool heating components on an inverter circuit substrate composing an inverter control means, and to achieve a reduction in size, weight and cost.SOLUTION: In this cooling device for an air compressor, the inverter substrate 28 with the heating components 26 composing the inverter control means 9 mounted on the rear surface of the substrate is stored in a case 30 composed of material having sufficient thermal conductivity so that the heating components 26 are brought into close contact with the bottom surface of the case 30, and the case 30 is downwardly arranged so that the bottom surface is upwardly directed between a pair of air tanks 5, 6 arranged in parallel to each other at an interval and on the lower side of at least one of an electric motor 2 and compressors 3, 4. An airflow generated by cooling fans 20, 21 driven by the electric motor 2 are guided along the bottom surface of the case 30, thereby cooling the heating components 26 through the case 30.

Description

  The present invention includes an electric motor that is driven and controlled via an inverter control means, a compressor that is driven by the electric motor to generate compressed air, and an air tank that stores the compressed air generated by the compressor. The present invention relates to an air compressor provided.

  In general, an air compressor is an electric motor that is rotationally driven by the supply of electric power, a compressor that is driven by the electric motor and compresses and discharges air sucked from the outside, and compressed air discharged from the compressor. It is comprised by the air tank to store. The power supply to the electric motor that drives the compressor detects the rotational position of the rotor of the electric motor, and the frequency of the current and voltage supplied to the stator coil of the electric motor according to this detection output is variable. Thus, an inverter is provided that is provided with inverter control means that efficiently drives an electric motor to reduce power consumption.

  The inverter control means includes a power supply unit configured by a semiconductor switching element and other parts for switching current and voltage to the stator coil of the electric motor, and the power supply unit based on a rotational position detection signal of a rotor in the electric motor. An inverter including the power supply unit and the control unit in which the semiconductor switching element is mounted, because the semiconductor switching element forming the power supply unit generates heat during driving. There is a risk that the control means will be destroyed by heat and the electric motor cannot be controlled. Generally, a protection circuit formed on the circuit cuts off the circuit when the temperature of these parts reaches a predetermined temperature to prevent the parts from being destroyed. Since the compression operation is stopped every time the circuit is activated, workability is impaired. Therefore, in an air compressor using such inverter control means, it is necessary to cool the semiconductor switching element of the power supply unit in order to prevent overheating of the inverter control circuit.

  The semiconductor switching element of the power supply unit is formed as an independent inverter module to facilitate cooling of the component itself. In an air compressor using conventional inverter control means, this inverter module is Separated from the substrate of the power supply unit and attached to the heat sink, the heat sink with the inverter module attached is disposed between a pair of air tanks and below the electric motor, and the electric motor and the compressor are arranged. In order to cool the inverter module, the inverter module is cooled by an air flow generated by cooling fans attached to both ends of the rotating shaft of the electric motor.

JP 2000-283046 A

  In the above prior art, a heat dissipating plate having an inverter module as a heat generating component is disposed at the upper part between a pair of air tanks, and the inverter module is interposed via the heat dissipating plate by cooling air that cools the compressor and the electric motor. In order to cool the inverter module satisfactorily, it is necessary to prepare a heat sink with a large surface area, and it is necessary to secure a space for installing this heat sink. It was easy to hinder the size and weight of the machine.

  Further, in the prior art, the circuit board of the power supply unit constituted by other parts excluding the inverter module which is a heat generating part in the inverter circuit is separated from the inverter module and is directed upward at the lower part between the pair of air tanks. Thus, if the circuit board of the power supply unit and the inverter module are divided and arranged as described above, wiring such as a power supply line and a signal line between them is necessary. In some cases, the cost increases or the number of steps for assembling the compressor increases, which increases the cost of the compressor.

  The present invention eliminates the above-mentioned problems of the prior art, can efficiently cool the heat generating components on the inverter circuit board constituting the inverter control means, and can be further reduced in size, weight and cost. An object of the present invention is to provide a cooling device for an air compressor.

  The cooling device for an air compressor according to the present invention is integrally attached to one end of a motor housing of an electric motor whose rotation is controlled via an inverter control means, and is driven by the electric motor to generate compressed air. A compressor to be generated and a pair of air tanks that are formed in a long barrel shape so as to store the compressed air generated by the compressor and that are arranged in parallel at a distance from each other, the electric motor being Cooling air that is disposed above the pair of air tanks so that the axial direction of the electric motor is substantially parallel to the longitudinal axis of the air tank and that flows along the axial direction of the electric motor to the rotating shaft of the electric motor In the air compressor provided with a cooling fan for generating air and cooling the compressor and the electric motor by the cooling air, the inverter control An inverter board on which a heat generating component constituting the means is mounted on the back side of the substrate is housed in a case made of a material having good thermal conductivity so that the heat generating component is in close contact with the bottom surface of the case, The case is disposed downward between the pair of air tanks and at the lower side of at least one of the electric motor and the compressor so that the bottom surface is upward. The heat generating component of the inverter control means is cooled through the case by being guided along the bottom surface of the inverter.

  According to a second aspect of the present invention, at least the outer surface of the portion where the heat generating component is in close contact with the bottom surface of the case housing the inverter board extends substantially parallel to the rotating shaft of the electric motor. A heat dissipation plate comprising a plurality of fins is provided.

  The invention of claim 3 is characterized in that the heat radiating plate is attached in close contact with the bottom surface of the case.

  Furthermore, the invention of claim 4 is characterized in that the heat radiating plate is formed integrally with the case and provided on the bottom surface of the case.

  According to the air compressor cooling device of the present invention, in the air compressor that is driven via the electric motor that is rotationally controlled via the inverter control means, the heat generating component that constitutes the inverter control means is provided. The inverter board mounted on the back side of the board is housed in a case made of a material having good thermal conductivity so that the heat generating component is in close contact with the bottom surface of the case, and the case is placed in the pair of air tanks. Between and at the lower side of at least one of the electric motor and the compressor, the bottom surface is disposed downward and the air flow by the cooling fan is guided along the bottom surface of the case. Since the heat generating component of the inverter control means is cooled via the case, the heat generating component is in close contact with the case having a large thermal conductivity and a large area. , The cooling fan for cooling the compressor and the electric motor so that so as to cool the casing by the cooling fan, the heat generating components of the inverter control unit can be efficiently cooled. In addition, since the heat generating parts that make up the inverter control means and other parts can be placed on the integrated inverter board, wiring between the heat generating parts on the inverter board and other parts is not required, and costs can be reduced. It becomes. Furthermore, by attaching the electronic circuit board forming the inverter control means in the reverse direction in the case, the case is covered with the electronic circuit board, and insulation failure occurs due to dust or dirt accumulated on the board. It does not cause malfunction or malfunction. Further, it is possible to avoid insulation failure caused by dripping water such as rain water onto the substrate.

  According to a second aspect of the present invention, at least the outer surface of the portion where the heat generating component is in close contact with the bottom surface of the case housing the inverter board is substantially parallel to the rotating shaft of the electric motor. Since the heat dissipating plate composed of a plurality of extended fins is provided, it is possible to efficiently cool the heat generating components of the inverter control means by the cooling fan.

  According to the invention of claim 3, since the heat sink is attached in close contact with the bottom surface of the case, the heat sink is easily provided at an arbitrary position on the bottom surface of the case corresponding to the heat generating component. Thus, the heat generating component can be effectively cooled.

  Further, according to the invention of claim 4, since the heat sink is formed integrally with the case and provided on the bottom surface of the case, the heat sink and the heat sink can be obtained without impairing thermal conductivity from the case to the heat sink. Cooling of the heat-generating component through the case can be performed effectively.

The top view which removed the cover of the air compressor which implemented the cooling device of the present invention Side view showing a section of the same air compressor as in FIG. The front view which removes and shows the cover of the same air compressor as FIG. The perspective view which shows an inverter board | substrate, the case which accommodates this, and a heat sink The perspective view which shows the state which assembled | attached the case and cover which accommodated the inverter board | substrate to an air compressor

  The present invention aims to enable efficient cooling of the heat generating components on the inverter circuit board constituting the inverter control means, and to further reduce the size, weight and cost. An inverter board in which a heat generating component is mounted on the back side of the substrate is housed in a case made of a material having good thermal conductivity so that the heat generating component is in close contact with the bottom surface of the case, and the case Between the pair of air tanks and on the lower side of at least one of the electric motor and the compressor so that the bottom surface is upward, and the air flow by the cooling fan is directed to the bottom surface of the case This is realized by cooling the heat generating component of the inverter control means through the case by guiding along the case. It will be explained below.

  FIG. 1 shows an air compressor implementing the cooling device of the present invention, and shows the arrangement of the main components inside the air compressor with the cover represented by a dashed line in the drawing removed. The air compressor 1 includes an electric motor 2 that is rotationally driven when electric power is supplied, and two compressors 3 that are driven by the rotation of the electric motor 2 to suck and compress the atmosphere to generate compressed air. 4, a pair of air tanks 5 and 6 formed in a long barrel shape for storing compressed air generated by the compressors 3 and 4, and compressed air stored in the air tanks 5 and 6 at a predetermined pressure Compressed air take-out portions 7 and 8 for reducing the pressure to be supplied to an air working tool and the like, and inverter control means 9 (shown in FIG. 2) for controlling the rotation of the electric motor 2 are provided.

  The pair of air tanks 5, 6 are arranged side by side on a plane at intervals so that the longitudinal axes of the air tanks 5, 6 are substantially parallel to each other, and are welded between the air tanks 5, 6. The frame 10 is connected to each other and can be placed on a floor surface or the like by installation legs 11 attached to the lower surfaces of the air tanks 5 and 6. Further, above the pair of air tanks 5, 6, the electric motor 2 is arranged such that the rotation axis of the electric motor 2 is substantially parallel to the longitudinal axis of the air tanks 5, 6. A crankcase 12 is integrally formed on one end side of the motor housing of the electric motor 2, and the two compressors 3, 4 for sucking air into the crankcase 12 and generating high-pressure compressed air. Is attached.

  The two compressors 3 and 4 constitute a two-stage compressor, and the first-stage compressor 3 and the second-stage compressor 4 are opposed to both side surfaces of the crankcase 12 in a substantially horizontal direction. It is attached as follows. The first stage compressor 3 compresses the air sucked through the crankcase 12 to an intermediate pressure and supplies the compressed air to the second stage compressor 4 through the primary discharge pipe 13. The second-stage compressor 4 compresses the intermediate pressure compressed air supplied from the first-stage compressor 3 through the primary discharge pipe 13 to the high pressure range, and passes through the secondary discharge pipe 14 to the one air. The fuel is supplied to the tank 5. The two air tanks 5, 6 are communicated with each other through the communication pipe 15, and the compressed air supplied into one air tank 5 flows through the communication pipe 15 to cause the other air tank 5, 6 to communicate with the other air tank 5, 6. By circulating into the air tank 6, the pressure in the air tanks 5 and 6 is kept the same.

  Compressed air extraction portions 7 and 8 for extracting compressed air from the air tanks 5 and 6 to a pneumatic tool or the like are provided for each of the air tanks 5 and 6. The compressed air outlets 7 and 8 are a pressure reducing valve 16 for reducing the pressure of the compressed air stored in the air tanks 5 and 6 to an arbitrary pressure used in an air tool or the like, and a pressure reduced by the pressure reducing valve 16. A secondary pressure gauge 17 for displaying air pressure and a socket portion 18 for connecting a plug attached to the other end of the air hose, one end of which is connected to a pneumatic tool or the like. In this embodiment, each of the compressed air outlets 7 and 8 is formed with two sockets 18 so that the compressed air can be simultaneously supplied from one compressed air outlet 7 and 8 to two tools. . One compressed air outlet 8 is provided with a primary pressure gauge 19 for displaying the pressure value of the compressed air generated in the compressors 3 and 4 and stored in the air tanks 5 and 6. .

  As shown in FIGS. 1 and 2, cooling fans 20 and 21 are attached to both ends of the rotating shaft of the electric motor 2, and cooling is performed by these cooling fans 20 and 21 when the electric motor 2 is driven to rotate. The compressors 3 and 4 and the electric motor 2 are cooled by generating wind. The cooling fan 20 attached to the end of the rotating shaft on one side protruding from the end of the crankcase 12 to which the compressors 3 and 4 are attached is formed by an axial fan, and the cover 22 Atmospheric air is sucked into the cover 22 from the opening 23 formed in the air flow, and this air flows along the outer peripheral surfaces of the motor housings of the compressors 3 and 4 and the electric motor 2. Thus, the compressor housings 3 and 4 and the motor housing of the electric motor 2 are cooled. The cooling fan 21 attached to the end of the rotating shaft on the other side of the electric motor 2 is a sirocco fan, and is formed in the cover 22 by sucking out air in the motor housing from the end of the motor housing. By discharging to the outside of the cover 22 through the opening 24, an air flow is generated in the motor housing to cool the winding portion of the electric motor 2.

  The electric motor 2 is rotationally controlled by detecting the rotational position of the rotor of the electric motor 2 by detecting means such as a Hall element, and by performing inverter control on the supply of electric power to the stator coil of the electric motor 2 based on this detection output. It is supposed to be. The electric motor 2 is connected to an external power source via the inverter control means 9 and is controlled to rotate by electric power supplied to the stator coil via the inverter control means 9. As shown in FIGS. 2 and 3, the inverter control means 9 controls the inverter module 26, which is constituted by a semiconductor switching element or the like that supplies power to the stator coil of the electric motor 2, and the inverter module 26. Circuit components 27 other than the inverter module 26, such as capacitors, an inverter board 28 on which the inverter modules 26 and the circuit components 27 are mounted, and a Hall element that detects the rotational position of the rotor of the electric motor 2. The control board 29 is configured by mounting components for controlling the inverter board 28 based on the detection signal.

  The inverter module 26 among the components constituting the inverter control means 9 is the heat generating component with the largest heat generation amount, and the inverter module 26 is a circuit component 27 such as a capacitor other than the inverter module 26 as shown in FIG. Is mounted on the back side of the inverter board 28 so that the metal surface exposed on the surface of the inverter module 26 faces the upper surface in the drawing. In this embodiment, the control board 29 for controlling the inverter control board 28 is formed separately from the inverter board 28. However, the control board 29 and the inverter board 28 may be integrated. Thus, by forming the two substrates integrally, the wiring between the substrates 28 and 29 is not necessary, and the cost can be further reduced.

  2 and 3, the gap between the pair of air tanks 5 and 6 accommodates the inverter board 28 and the control board 29 formed in a box shape with, for example, aluminum having high thermal conductivity. The case 30 is attached so that the opening faces downward and the bottom surface faces upward. The case 30 is disposed substantially horizontally in the gap between the air tanks 5 and 6 so that the cooling air generated by the cooling fans 20 and 21 flows along the outer surface of the bottom surface of the case 30. I have to. The surface of the inverter board 28 forming the inverter control means 9 is accommodated so that the surface on which the inverter module 26 is mounted faces the bottom surface of the case 30, and the metal surface on the surface of the inverter module 26 is the case 30. It is attached in close contact with the bottom of the. Further, as shown in FIGS. 2, 3 and 5, a cover 31 is mounted on the lower side of the inverter board 28 to protect the lower surface side of the board.

  As described above, the inverter module 26 having the largest heat generation among the components constituting the inverter control means 9 is mounted on the back side of the substrate, and this inverter module 26 is formed of a metal having a high thermal conductivity. Since it is attached in close contact with the case 30 of the area, the inverter module 26 is efficiently cooled through the case 30 by the cooling air flowing along the outer surface of the case 30 of the large area, and the inverter module 26 and other It can prevent the component from being damaged by heat.

  Further, a heat radiating plate 32 formed with a large number of fins 33 extending substantially parallel to the rotating shaft of the electric motor 2 is formed on the outer surface of the bottom surface of the case 30, and the rear surface of the heat radiating plate 32 is the bottom surface of the case 30. The cooling efficiency of the inverter module 26 through the case 30 is further improved by the cooling air generated by the cooling fans 20 and 21.

  In addition, the inverter module 26 is mounted on the back side of the inverter board 28, and the inverter board 28 is housed in the case 30 with the surface on which components other than the inverter module 26 are mounted facing downward. It is possible to prevent dust or the like entering from the gaps 30 from accumulating on the substrate and causing malfunctions or malfunctions due to defective insulation between components caused by these dusts. Furthermore, it can be avoided that moisture such as rainwater drops on the substrate to cause insulation failure. In addition, since the electric wires connected to various connectors (not shown) provided on the substrate are provided so as to extend from the lower side of the substrate toward the substrate, moisture is transmitted through the electric wires to various types. It can prevent being led to the connector part.

  In the description of the above embodiment, two compressors 3 and 4 are provided in a horizontally opposed manner from a crankcase integrally formed on one end side of the electric motor 2 so as to generate compressed air in a high pressure region. However, the present invention is not limited to this, for example, an air compressor provided with a compressor configured to perform one-stage compression or three-stage compression or more. It may be configured. Further, the three and four compressors are not limited to be arranged in the horizontal direction, and a plurality of compressors may be arranged in parallel or may be arranged in a V shape or the like. Although the inverter module 26 has been described as an example of the heat generating component, the present invention is not limited to this, and the present invention can also be applied to various heat generating components such as a rectifier diode element and a motor drive power supply module. .

DESCRIPTION OF SYMBOLS 1 Air compressor 2 Electric motor 3, 4 Compressor 5, 6 Air tank 9 Inverter control means 20, 21 Cooling fan 26 Inverter module (heating component)
28 Inverter board 30 Case 32 Heat sink 33 Fin

Claims (4)

An electric motor whose rotation is controlled through an inverter control means, a compressor that is integrally attached to one end of the motor housing of the electric motor and that is driven by the electric motor to generate compressed air, and generated by the compressor A pair of air tanks that are formed in a long barrel shape so as to store the compressed air and that are arranged in parallel at a distance from each other, and the axial direction of the electric motor is the longitudinal direction of the air tank. A cooling fan that is disposed above the pair of air tanks so as to be substantially parallel to the direction axis and that generates cooling air that flows along the axial direction of the electric motor is provided on the rotating shaft of the electric motor. In the air compressor configured to cool the compressor and the electric motor by:
An inverter board on which the heat generating parts constituting the inverter control means are mounted on the back side of the board, so that the heat generating parts are in close contact with the bottom face of the case in a case made of a material having good thermal conductivity. And the case is disposed downwardly between the pair of air tanks and at the lower side of at least one of the electric motor and the compressor so that the bottom surface is upward. A cooling device for an air compressor, wherein the heat generating component of the inverter control means is cooled through the case by guiding the air flow along the bottom surface of the case.   On the bottom surface of the case housing the inverter board, a heat radiating plate made of a plurality of fins extending substantially parallel to the rotating shaft of the electric motor is provided on at least the outer surface of the portion where the heat generating component is in close contact. The cooling device for an air compressor according to claim 1, wherein the cooling device is provided.   The cooling device for an air compressor according to claim 2, wherein the heat radiating plate is attached in close contact with a bottom surface of the case.   The cooling device for an air compressor according to claim 2, wherein the heat radiating plate is formed integrally with the case and provided on a bottom surface of the case.

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