JP2010093986A - Device for controlling electric actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, in the prior art, an increase in temperature of an element is suppressed by using an air flow caused by natural convection, but a means for suppressing an increase in temperature of the element which depends on natural convection inside a control device takes time to suppress an increase in temperature of the element, and convention hardly occurs in a high-temperature operation with a small difference in temperature. <P>SOLUTION: A device for controlling an actuator which is attached integrally to a housing of the actuator is equipped with a control circuit board on which a heating element is mounted, a case for storing the control circuit board inside, an opening formed between the housing and the case to electrically connect the actuator and the control circuit board, and a breathing hole formed in a portion of the case within a predetermined range from the element to allow gases to go in and out of the case. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for an electric actuator mounted on an automobile.

  2. Description of the Related Art Conventionally, in a control device installed in an automobile engine room or the like, a microcomputer that executes arithmetic processing, various integrated circuits, MOSFETs that are driving elements of actuators, and the like are mounted on a substrate, and these are connected to a metal or resin casing It is configured to be accommodated by a cover or the like.

  Various heat dissipation measures are taken for elements that are likely to generate heat among electronic components mounted on a substrate, particularly in these control devices.

  Here, there is a technique of providing an intake port for introducing outside air and an exhaust port for discharging on the outer wall portion of the electronic control unit (see Patent Document 1). Further, there is a technique in which a groove functioning as a breathing hole is provided in a portion positioned on the upper side and a portion positioned on the lower side of the electronic control device (see Patent Document 2).

Japanese Patent Laid-Open No. 10-242677 JP 2003-273556 A

  According to Patent Documents 1 and 2, the temperature rise value of the element is suppressed by using the air flow by natural convection, but if the element temperature rise suppression means that relies on natural convection in the control device is used. However, there are problems that it takes time to implement and that convection hardly occurs during a high temperature operation with a small temperature difference.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a control device capable of forcibly and timely breathing with the outside of the control device by forcibly flowing the air in the control device and the electric actuator when the electric actuator is driven. .

  In order to solve the above problems, one of the desirable embodiments of the present invention is as follows.

  A control device that is integrally attached to the actuator housing and controls the actuator includes a control circuit board on which an element that generates heat is mounted, a housing that houses the control circuit board, and a housing between the housing and the housing. An opening for making electrical connection between the actuator and the control circuit board, and a breathing hole through which gas enters and exits from the outside of the housing are provided in a portion of the housing within a predetermined range from the element.

  ADVANTAGE OF THE INVENTION According to this invention, when an electric actuator drives, the electric actuator and the air in a control apparatus can flow forcedly, and the control apparatus which can breathe with the exterior of a control apparatus reliably and timely can be provided.

  Hereinafter, the present embodiment will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of the control device 1 accommodated in the housing from a cross-sectional direction of the control circuit board 6. The control device 1 controls the electric actuator 27 that is integrally assembled with the housing 2.

  Here, the description will be made on the assumption that the actuation mechanism of the electric actuator 27 is a brake booster for automobiles using a DC brushless motor as a drive source, but the present invention is not limited thereto. An electric actuator 27 such as a DC motor, a linear motor, or a piezoelectric element in various devices such as an electric power steering, an electric brake, an electric hydraulic brake, and an electric parking brake may be used, and the electric actuator 27 and the control device 1 are integrated in appearance. The electrical connection portion 29 between the control circuit board 6 and the actuator mechanism only needs to be provided in the opening 5 through which air passes.

  When this device is a brake booster for automobiles, it is installed in the engine room, so it is sealed except for the breathing hole 3 provided in the housing of the control device, and almost all gases and liquids pass through it. It is considered impossible. The breathing hole 3 is also provided with a filter that allows gas to pass but not water. Therefore, here, only the gas via the breathing hole 3 exchanges with the outside, other than the electrical connection with the outside via a connector (not shown) and the exchange of heat via the object surface. Assume that A plurality of breathing holes 3 may exist.

  When the actuation mechanism performs a motion 28 (translational movement in the drawing) that causes a volume fluctuation of the gas inside the housing 2, for example, the electric actuator 27 moves in the direction in which the volume of the gas inside increases (to the left in the drawing). When it moves, the air inside the control device 1 is sucked from the opening 5 by the negative pressure caused by the volume fluctuation that occurs, so that external gas is inevitably sucked from the breathing hole 3 of the control device 1, and the result As a result, an air flow from the breathing hole 3 toward the opening 5 occurs.

  Conversely, for example, when the electric actuator 27 moves in the direction in which the gas volume in the housing 2 decreases (toward the right in the figure), the positive pressure due to the generated volume fluctuation causes the opening 5 to move toward the inside of the control device 1. Since the air is exhausted, the exhaust from the breathing hole 3 of the control device 1 to the outside is inevitably generated. As a result, the flow of air from the opening 5 to the breathing hole 3 is generated.

  Therefore, the heating element 7 mounted on the control circuit board 6 is located in the air flow, and particularly if it is in the vicinity of the opening 5 and the breathing hole 3, the effect of cooling by the air flow can be obtained. I can do it.

  In addition, in the case of such a controller-integrated actuator, the control circuit board 6 mostly controls the movement of the actuator mechanism, and the timing at which these heating elements 7 generate heat is almost during the operation of the actuator, that is, It can be said that the air is flowing.

  For this reason, it is possible to produce an air flow and cool it in accordance with the time when the element generates heat without requiring any special control or mechanism. This not only has the effect of reducing measures such as mounting heat conduction parts between the element and the surrounding housing, or providing heat dissipation fins, but also a device that relies on natural convection by providing multiple breathing holes. In comparison, the amount of time deviation with respect to the heat generation timing of the element is small, and furthermore, even one breathing hole to the outside can finally breathe, so that the cost of the filter parts can be reduced.

  In addition, since it is not natural convection, there is no restriction on the installation location of the breathing hole to the outside, and it can be said that the degree of freedom in design is great even when various devices such as automobiles are densely packed and there is no allowance for mounting. When converting a part of the mechanism part, for example, a rotating mechanism into an actuator that translates (linear motion), the rotating mechanism part has a blade-like shape for stirring gas, The effect is greater.

  For example, even if the electric actuator 27 moves but the volume inside the housing 2 does not change, if the actuator generates heat when energized, the air inside the housing 2 expands and the generated positive pressure is generated. Thus, since air is exhausted from the opening 5 toward the inside of the control device 1, exhaust from the breathing hole 3 of the control device 1 to the outside inevitably occurs, and as a result, breathing from the opening 5. An air flow toward the hole 3 is generated.

  Therefore, the heating element 7 mounted on the control circuit board 6 is located in the air flow, and particularly if it is in the vicinity of the opening 5 and the breathing hole 3, the effect of cooling by the air flow can be obtained. Of course, if the movement of the actuator mechanism is controlled by the control circuit board 6, the timing at which these heat generating elements 7 generate heat is almost the time when the actuator is operating (heat generation), that is, when the air flows. .

  For this reason, it is possible to produce an air flow and cool it in accordance with the time when the element generates heat without requiring any special control or mechanism.

  With respect to the arrangement of the elements with respect to this series of air flows, FIG.

  If the heating element 7 on the control circuit board 6 is located within a predetermined range (near) from the breathing hole 3 to the outside, the cooling effect by the air flow is great. On the other hand, even in the vicinity of the opening 5, the same level of air flow as that in the vicinity of the breathing hole can be expected. If the arrangement is difficult in any case, the breathing hole 3 and the opening 5 may be positioned on a substantially straight line. In this case, if the fluid analysis is performed after reproducing the both surfaces of the control circuit board 6 and the shape inside the control device 1, it is possible to find a place where the flow rate can be effectively cooled.

  FIG. 5 is a diagram showing a control device in the case of being divided into a power system board 6-1 through which a large current for driving the electric actuator 27 flows and a signal system board 6-2 for controlling the current. It is. In this case, the heating element 7-2 of the signal system board 6-2 includes a microcomputer and a power supply IC, and the heating element 7-1 of the power system board 6-1 includes a driving element such as a transistor. In addition to the two substrates shown in FIG. 1, the essence of cooling the heating elements 7-1 and 7-2 by placing them in the air flow and the timing of the air flow are almost the same. does not change.

  FIG. 2 is a diagram illustrating a schematic configuration of the control device 1 from a cross-sectional direction of the control circuit board 6. The difference from FIG. 1 is the assembly position of the control device 1 with respect to the housing 2, and the translational direction of the electric actuator 27 that translates is the normal direction of the control circuit board 6.

  In the case of this embodiment, the description will proceed on the assumption that the actuator mechanism of the electric actuator 27 is an electric brake caliper for automobiles using a DC brushless motor as a drive source, but is not limited thereto.

  If this device is an electric brake caliper for an automobile, it is mounted near the wheel under the spring of the automobile, so that a seal or the like is applied except for the breathing hole 3 provided in the casing of the control device. Etc. should be made almost impossible to pass. Also in the breathing hole 3, a filter that allows gas to pass but does not allow water to pass should be shaped so that dust or the like is not deposited around it as much as possible, for example, surrounded by a bowl shape. Here, it is assumed that only the gas through the breathing hole 3 exchanges with the outside in addition to the electrical connection with the outside through a connector (not shown) and the exchange of heat through the object surface. To do.

  Therefore, when the electric actuator 27 moves (translates) so as to cause a volume fluctuation of the gas inside the housing 2, such as when the braking force is generated and the pad is pressed against the rotor, the internal gas When the actuator device moves in the direction in which the volume increases (leftward in the figure), as in the first embodiment, the air inside the control device 1 is sucked from the opening 5 with the negative pressure caused by the generated volume fluctuation. Inevitably, an external gas is sucked from the breathing hole 3 of the control device 1, and as a result, an air flow from the breathing hole 3 toward the opening 5 occurs. The reverse operation is the same as in the first embodiment.

  Therefore, if the heat generating element 7 mounted on the control circuit board 6 is positioned in the air flow, it is particularly in the vicinity of the opening 5 and the breathing hole 3, and cooling by the air flow is possible. An effect can be obtained.

  In addition, when the control circuit board 6 controls the movement of the actuator mechanism, it can be said that the timing at which these heating elements 7 generate heat is almost during the operation of the actuator, that is, when the air flows. Without the need, it can be cooled by creating a flow of air just in time for the element to generate heat.

  In this embodiment, since forced breathing is performed by an actuator, even if the device is submerged as one aspect assumed for a brake caliper, it has a feature that it can be evacuated when the inside is set to the positive pressure side. If it is provided in the connection harness routed from above the vehicle spring, the supply / exhaust source can be secured almost always.

  FIG. 4 is a diagram showing a system including the control device 1 when the electric actuator 27 of FIG. 1 is a brake booster. In addition, description of the drive mechanism for driving | running | working and the figure to the brake device vicinity are abbreviate | omitted.

  Further, in this drawing, in order to schematically show the system configuration, detailed component configurations unnecessary for the description of the present embodiment such as a reservoir tank are omitted. Furthermore, although the positional relationship between the actuator mechanism and the control device 1 is positioned parallel to the axial direction of the brake rod 18, this may be changed to FIG. 2 or other positional relationships depending on the mountability and other requirements. Thus, as in the present embodiment, it is shown that the actuator mechanism and the control device 1 have an integral structure in appearance, and a connection portion between the control circuit board 6 and the actuator may be provided.

  First, the brake pedal 21 as an input mechanism is not limited to a pedal as long as it can replace a pedal that can be input by the driver, such as a handle or a lever, depending on the type of automobile. Further, the hydraulic braking device connected by the oil passages 23 and 24 as the output mechanism is not limited to the braking device as long as it is an output mechanism for controlling the behavior of the vehicle.

  The electric actuator of this embodiment is connected to the oil passages 23 and 24 via the master cylinder 22 and the like via the brake rod 18 and the oil passages 23 and 24 are connected to the output mechanism of each wheel via the hydraulic device. The oil pressures of the oil passages 23 and 24 are distributed to the pipes, and the generated oil pressures respectively become piston thrusts of the braking device, and the friction material in the braking device is pressed against the rotor connected to the wheels to generate the braking force on the vehicle. .

  Thus, the electric actuator can generate a braking force on the output mechanism and a reaction force on the brake pedal 21. Here, only typical operations will be described.

  First, when the driver depresses the brake pedal 21, the brake rod 18 is pushed in and hydraulic pressure is generated in the master cylinder 22.

  On the other hand, in order to amplify the braking force, the depression amount is sensed by the stroke sensor 20, the motor rotation angle is calculated by the signal system board 6-2 according to the value, and the rotation angle detection sensor 19 rotates the motor. A current is passed from the power system substrate 6-1 to the stator 13 while monitoring the corners. As a result, the rotor 14 is rotated, and the rotational motion of the motor is changed to a linear motion by a rotation / linear motion conversion mechanism 15 such as a ball screw, and the hydraulic pressure amplified in the master cylinder 22 by the piston 16 moving thereby. Is generated.

  Accordingly, the volume of the gas present inside the housing 2 changes due to the movement of the piston 16. For example, when the piston 16 moves in the direction of amplifying the hydraulic pressure (leftward in the figure), the volume increases inside. Therefore, the atmospheric pressure decreases.

  On the other hand, when the brake fluid pressure is released, the piston 16 moves to the right in the figure, so that the interior volume decreases and the atmospheric pressure increases.

  Due to the increase or decrease of the internal pressure due to such volume fluctuation, the surrounding air is taken in and discharged to the surroundings through the filter 4 in the breathing hole 3 provided in the housing 1 of the control device through the opening 5. Such a breathing motion can be performed.

  This indicates that when the breathing operation due to volume fluctuation is performed, the actuator is in operation, and the heating elements 7-1 and 7-2 including the driving elements on the substrate are also operated to generate heat. In other words, since the breathing operation is performed in accordance with the heat generation timing of the element, heat can be efficiently taken by creating an air flow around the element in a timely manner when the element temperature should be lowered. In natural convection, air starts to move after the ambient temperature around the element rises, so that there is a difference in timing from the temperature rise to the start of air movement.

  FIG. 6 shows the diameter of each breathing hole or the flow path of the gas flowing into each breathing hole so that the unit air flow rates when the respective pressures in the plurality of breathing holes are equal in the control device 1 of FIG. It is a figure which shows schematic structure of the control apparatus made to differ in each from the normal line direction of the control circuit board 6 plane.

  Thus, by providing a plurality of breathing holes 3 and changing the flow velocity in each hole, the air flow on the control circuit board 6 can be disturbed, and a greater cooling effect can be expected. Alternatively, if the air flow on the control circuit board 6 can be disturbed by changing the distance from the openings 5 of the plurality of breathing holes 3 in the same manner, the diameters of the plurality of holes can be the same. In this case, the cost can be reduced by unifying the types of filters for the breathing holes.

  In any case, there is no change in providing a hole for breathing in the opening 5, and in the air flow between the breathing hole 3 and the opening 5, the heating element on the control circuit board 6 is provided. By placing 7, the essence of cooling the heating element 7 and the timing of air flow is almost the same as in the case of FIG. 1.

The figure which shows schematic structure of a control apparatus from the cross-sectional direction of a control circuit board. The other figure which shows schematic structure of a control apparatus from the cross-sectional direction of a control circuit board. The figure which shows schematic structure of a control apparatus from the normal line direction of a control circuit board plane. The figure which shows the system containing the control apparatus of a brake booster. The figure which shows the control apparatus containing a power system board | substrate and a signal system board | substrate. The other figure which shows schematic structure of a control apparatus from the normal line direction of a control circuit board plane.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control apparatus 2 Housing 3 Breathing hole 4 Filter 5 Opening part 6 Control circuit board 7 Heating element 19 Rotation angle detection sensor 21 Brake pedal 27 Electric actuator 28 Actuator movement 29 Connection part of control circuit and actuator

Claims (7)

In a control device that is integrally attached to the actuator housing and controls the actuator,
A control circuit board on which a heat generating element is mounted;
A housing for accommodating the control circuit board therein;
Between the housing and the housing, an opening for electrically connecting the actuator and the control circuit board;
A control device comprising a breathing hole through which gas enters and exits the outside of the housing in a portion of the housing within a predetermined range from the element.   The control device according to claim 1, wherein there are a plurality of the breathing holes.   The control device according to claim 1, wherein the actuator generates a pressure fluctuation in the actuator and the control device by changing a volume during driving.   The control device according to claim 1, wherein the actuator raises a temperature at the time of driving to generate a pressure fluctuation inside the actuator and the control device.   5. The control device according to claim 1, wherein the control circuit board is divided into a power system board through which a current for driving the actuator flows and a signal system board for controlling the current. 6. .   The control device according to claim 1, wherein the element is disposed in a region in which the breathing hole and the opening are connected in a substantially straight line.   The control according to claim 2, wherein the diameter of each breathing hole or the flow path of the gas flowing into each breathing hole is made different so that the unit air flow rate when the respective pressures in the plurality of breathing holes are equal is different. apparatus.

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