JP2006322424A - Motor actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration of performance of a motor due to over heat of the motor 5 by improving heat radiation performance of the motor 5 while reducing the weight of an actuator case 6. <P>SOLUTION: A metal is used for a sub case 9 while reducing weight of an actuator case 6 by using a resin for a main case 7, and at least a part of the sub case 9 is projected to a rear side in the axial direction of the motor 5 from a partition wall 51 of a main case 7. The sub case 9 easily elastically deforms in thickness directions of the cylinder part 61 and the bottom part 62 by forming the sub case 9 in a bottomed cylindrical shape from a cylindrical metal thin plate. Consequently, since an outer circumference surface of a yoke 30 of the motor 5 tightly adheres on an inner circumference surface of the sub case 9, heat radiation performance of the motor 5 can be further improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor actuator including a motor case that houses a motor therein, and more particularly to a motor actuator including a motor case that can further improve the heat dissipation performance of the motor.

[Conventional technology]
2. Description of the Related Art Conventionally, an intake air flow control device for an internal combustion engine mounted on a vehicle such as an automobile is rotatably accommodated in a throttle body by driving a motor in accordance with a driver's accelerator pedal depression amount (accelerator operation amount). The throttle valve is configured to control a valve angle. As shown in FIG. 3, the motor 102 for changing the valve angle of the throttle valve 101 is installed in the vicinity of the throttle valve 101, so that it is formed in a cylindrical shape integrally formed on the outer wall portion of the throttle body 103. (See, for example, Patent Document 1). The motor case 104 is arranged on the outermost air side of the throttle body 103 so as to be exposed to the outside air in consideration of the heat dissipation of the motor 102, and the outer peripheral surface of the motor case 104 is a heat radiating surface. In the motor 102, the flange portion 111 is fastened and fixed to the base plate 112 using bolts 113. The base plate 112 is fastened and fixed to the motor case 104 using bolts 114 so that the motor 102 is fixed (supported) to the motor case 104.

[Conventional technical problems]
However, in the intake air flow control device for an internal combustion engine described in Patent Document 1, when the motor case 104 is formed of a metal material for the purpose of further improving the heat dissipation performance of the motor 102, motor peripheral components including the motor case 104 are included. The problem arises that the weight of the is increased. Further, when the motor case 104 is formed of a resin material for the purpose of reducing the weight of the motor peripheral parts, the resin material has poor thermal conductivity, and the temperature of the motor 102 increases as the heat dissipation of the motor 102 deteriorates. There is a problem that the performance of the motor 102 is deteriorated (for example, the motor output is reduced). In addition, since the intake flow control device for an internal combustion engine described in Patent Document 1 requires bolts 113 and 114 to fix the motor 102 to the motor case 104, the number of parts is large and the number of assembly steps is increased. There was a problem that the product cost was high.

  Therefore, as shown in FIG. 4, the motor 102 is insert-molded inside the resin housing 105, thereby eliminating the fastening parts for fixing the motor 102 to the resin housing 105 and reducing the number of parts and the number of assembly steps. However, there is an intake flow control device for an internal combustion engine designed to reduce product cost (see, for example, Patent Document 2). This is arranged such that a part of the metal yoke 121 of the motor 102 is exposed in the intake passage 122 slightly upstream from the throttle valve 101 and directly contacts the air flow flowing in the intake passage 122. With this configuration, the heat dissipation of the motor 102 is promoted, and the heat dissipation of the motor 102 is improved. As a result, it is possible to prevent a reduction in motor torque due to overheating of the motor 102.

  However, in the intake flow control device for an internal combustion engine described in Patent Document 2, since the motor 102 is insert-molded inside the resin housing 105 and fixed to the resin housing 105, the metal yoke 121 and the resin housing of the motor 102 are fixed. Due to the difference in thermal expansion coefficient from 105, a gap may be formed between the metal yoke 121 of the motor 102 and the resin housing 105, and the motor 102 may rattle within the resin housing 105. In this case, there is a problem that the positional accuracy between the output shaft 123 of the motor 102 and the power transmission means 124 is deteriorated, and the malfunction of the throttle valve 101 occurs.

  In addition, as shown in FIG. 5, the metal yoke 121 of the motor 102 is brought into close contact with the metal housing 106 and exposed so that the outer surface of the metal housing 106 is exposed to the outside air. There is an intake flow control device for an internal combustion engine configured to do so (for example, see Patent Document 3). This is because the cooling fan 126 is attached to the armature 125 of the motor 102 and the outside air is introduced from the breathing hole 127 provided in the metal housing 106, thereby directly cooling the inside of the motor 102 and efficiently cooling the motor 102. ing. Here, 107 is a throttle opening sensor, 108 is an accelerator opening sensor, 109 is a crank angle sensor, and 110 is an engine control unit (ECU).

However, in the intake flow control device for an internal combustion engine described in Patent Document 3, it is necessary to bring the outer peripheral surface of the metal yoke 121 of the motor 102 into close contact with the inner peripheral surface of the motor housing hole 129 of the metal housing 106. For this reason, it is conceivable to press-fit the metal yoke 121 of the motor 102 into the motor housing hole 129 of the metal housing 106. However, since the metal housing 106 is thick and hardly elastically deformed, the metal yoke 121 of the motor 102 is not easily deformed. The motor 102 cannot be assembled to the metal housing 106 unless the dimensional accuracy between the outer diameter and the inner diameter of the motor housing hole 129 of the metal housing 106 is strictly controlled. Further, since it is necessary to strictly manage the dimensional accuracy between the outer diameter of the metal yoke 121 of the motor 102 and the inner diameter of the motor housing hole 129 of the metal housing 106, there arises a problem that the product cost increases. Further, since the outside air is introduced into the motor 102 from the breathing hole 127, foreign matter such as dust and dirt may enter the inside of the motor 102 together with the outside air. When a foreign object is caught between the rotor side and the stator side of the motor 102, there is a problem that the motor 102 is locked and a malfunction of the throttle valve 101 occurs.
JP-A-10-252510 (page 1-5, FIG. 1) JP 2002-309966 A (page 1-6, FIG. 1 to FIG. 2) JP 2003-003868 A (page 1-5, FIG. 1)

  An object of the present invention is to provide a motor actuator capable of preventing deterioration of the performance of the motor due to overheating of the motor by further improving the heat dissipation performance of the motor while reducing the weight of the motor case.

  According to the first aspect of the present invention, a motor case that houses a motor therein is constituted by a main case (resin case) formed of a resin material and a sub case (metal case) formed of a metal material. ing. Then, the motor is fixed to the main case, and further, the motor is held in close contact with the sub case having higher thermal conductivity than the main case. Then, by exposing at least a part of the sub case on the outer surface of the main case or projecting outside from the main case, the heat generated by the motor is transferred to the air flowing around the motor case through the sub case. It is possible to effectively dissipate heat.

  As a result, the main case is made of resin, so that the motor case can be reduced in weight while the sub case is metalized so that at least a part of the sub case is exposed on the outer surface of the main case, or the main case By projecting more outward, the heat dissipation performance of the motor can be further improved. Therefore, since the motor can be efficiently cooled, it is possible to prevent deterioration of the motor performance due to overheating of the motor. In addition, since the motor performance can be improved, the quality of the motor actuator can be improved.

  According to the second aspect of the present invention, the sub case is formed of the bottomed cylindrical thin plate, so that the sub case is easily elastically deformed (for example, in the plate thickness direction). Then, by providing a motor housing hole for tightly fitting the motor inside the sub case, the motor can be accommodated in the sub case without strict control of the dimensional accuracy between the outer diameter of the motor and the inner diameter of the motor housing hole. Can be easily assembled into the hole. As a result, it is not necessary to strictly manage the dimensional accuracy between the outer diameter of the motor and the inner diameter of the motor housing hole, so that the product cost can be reduced. In addition, by tightly fitting the motor inside the sub case, the degree of adhesion between the motor and the sub case increases, and the motor can be brought into close contact with the sub case. Thereby, the heat dissipation performance of the motor can be further improved.

  According to the third aspect of the present invention, the sub case is configured by the cylindrical portion that comes into contact with at least a part of the outer periphery of the motor and the bottom portion that comes into contact with one end portion in the central axis direction of the motor. Since the area in close contact with the case increases, the heat generated by the motor can be efficiently transmitted to the sub case. Thereby, the heat dissipation performance of the motor can be further improved.

  According to the fourth aspect of the present invention, the motor is fixed to the main case through the opening formed in the partition wall of the main case. That is, since a part of the motor protrudes outside from the partition wall of the main case, it is easily exposed to the air flowing around the motor case through the sub case. Thereby, the heat dissipation performance of the motor can be further improved. Note that one end side (front side or rear side of the motor) of the motor in the central axis direction protrudes outside the partition wall of the main case, or the radially outer diameter side of the motor is outside the partition wall of the main case. It does n’t matter if it pops out.

  According to the invention described in claim 5, the thermal expansion coefficient between the main case and the sub case is provided by providing the sub case that holds the motor in close contact with the main case to which the motor is fixed. Without being affected by the difference, the motor can be fixed to the main case, and the motor can be held in close contact with the sub case. According to the sixth aspect of the present invention, the rubber-based elastic body is sandwiched between the main case (resin case) formed of a resin material and the sub case (metal case) formed of a metal material. Since it is held, it is possible to absorb the difference in thermal expansion coefficient between the resin case and the metal case. As a result, the motor can be held and fixed inside the motor case without rattling.

  According to the invention described in claim 7, motor fastening means for fastening the motor to the main case may be provided. According to the invention described in claim 8, the motor fastening means has a function of fastening and fixing the motor to the main case (motor fastening and fixing means), and the sub case is mounted when the sub case is assembled to the main case. By combining the function of applying a load to the sub case in the direction of pressing against the main case (load applying means), the motor is fixed to the main case and the sub case is fixed to the main case by one type of motor fastening means. Can be performed simultaneously. Thereby, the motor can be fixed to the main case in a state of being in close contact with the sub case while reducing the number of parts and the number of assembling steps to reduce the product cost.

  According to the ninth aspect of the present invention, the rubber-based elastic body is sandwiched and held between the main case and the sub case. Since this rubber-based elastic body is compressed and deformed when a load is applied via the sub case from the motor fastening means that also serves as the load applying means, an elastic repulsive force is generated in the rubber-based elastic body. The rubber-based elastic body uses the elastic repulsive force to hermetically seal (seal and seal) the gap between the main case and the sub case, so that foreign matters such as water, dust, and dust can be removed from the main case. The motor case does not enter from the gap between the motor and the sub case. As a result, foreign matter does not enter the motor, so that the motor is not locked and the quality (control response, reliability, etc.) of the motor actuator can be improved. Also, since the rubber-based elastic body is sandwiched and held between the main case (resin case) made of resin material and the sub case (metal case) made of metal material, the resin case and the metal case The difference in thermal expansion coefficient with respect to can be absorbed. As a result, the motor can be held and fixed inside the motor case without rattling.

  The best mode for carrying out the present invention is to improve the heat dissipation performance of the motor while reducing the weight of the motor case, and to prevent the motor performance from being deteriorated due to overheating of the motor. The motor is fixed to and held in a state where the motor is in close contact with the sub case that has better thermal conductivity than the main case, and at least a part of the sub case is exposed on the outer surface of the main case, or from the main case Realized by projecting outside. In addition, the sub case is formed by a bottomed cylindrical thin plate for the purpose of contacting the motor to the sub case without strictly controlling the dimensional accuracy between the outer diameter of the motor and the inner diameter of the motor housing hole. Realized by making the case easily elastically deformed. In addition, the purpose of holding the motor without absorbing the difference in thermal expansion coefficient between the resin case and the metal case is to hold the rubber-based elastic body between the resin case and the metal case. It was realized. In addition, for the purpose of preventing foreign matter such as water, dust and dirt from entering the inside of the motor, the clearance between the main case and the sub case is hermetically sealed using the elastic repulsive force of the rubber-based elastic body. That was realized.

[Configuration of Example 1]
FIGS. 1 and 2 show a first embodiment of the present invention. FIG. 1 (a) shows a main structure of a motor actuator, and FIG. 1 (b) shows an overall structure of the motor actuator. FIG. 2 is a diagram showing a schematic configuration of an intake flow control device for an internal combustion engine.

  The intake flow control device for an internal combustion engine of the present embodiment is a longitudinal direction for accelerating combustion of an air-fuel mixture in a cylinder of an internal combustion engine (for example, a gasoline engine: hereinafter referred to as an engine) 1 mounted on a vehicle such as an automobile. An intake air flow generation device (vortex flow generation device) that can generate a vortex flow (tumble flow), and is integrally provided in the intake system of the engine 1. The intake flow control device for an internal combustion engine includes an engine intake pipe 2 that forms an intake passage communicating with a cylinder of the engine 1, an intake flow control valve 3 that is housed in the engine intake pipe 2 so as to be freely opened and closed, and the intake air A motor actuator 4 that drives the flow control valve 3 in the valve opening direction (or valve closing direction) and a valve biasing means such as a spring that biases the intake flow control valve 3 in the valve closing direction (or valve opening direction) (see FIG. And an engine control unit (not shown: hereinafter referred to as ECU) that controls the valve opening degree of the intake flow control valve 3 by driving the motor 5 of the motor actuator 4.

  The motor actuator 4 includes a motor 5 as a power source, a gear reduction mechanism that reduces the rotational speed of the motor 5 to a predetermined reduction ratio, and an actuator case (motor) that houses the motor 5 and the gear reduction mechanism inside. Case) 6. The actuator case 6 includes a main case 7 and a cover 8 made of a resin material, a sub case 9 made of a metal material, and motor fastening means for fastening the motor 5 to the main case 7. ing. The motor actuator 4 is compressed when it receives a load (fastening axial force) from the bracket 11 via the motor 5 and the sub case 9 and the screw 11 for fastening and fixing the motor 5 to the main case 7 via the bracket 10. A rubber seal 12 is provided that is deformed and hermetically seals the gap between the main case 7 and the sub case 9.

  Here, as shown in FIG. 2, the engine 1 obtains an output by heat energy obtained by combusting a mixture of intake air and fuel in the combustion chamber 13, and an intake manifold 14 and an exhaust manifold 15. And a cylinder block that forms a combustion chamber 13 into which an air-fuel mixture is drawn from an intake port provided in the cylinder head. The intake port formed on one side of the cylinder head is opened and closed by the intake valve 16, and the exhaust port formed on the other side of the cylinder head is opened and closed by the exhaust valve 17. In FIG. 2, a double-type intake valve 16 and a double-type exhaust valve 17 are provided for the combustion chamber 13 of one cylinder, but only one is provided for the combustion chamber 13 of one cylinder. Three or more intake valves 16, only one, or three or more exhaust valves 17 may be provided. A piston 18 connected to a crankshaft (not shown) of the engine 1 via a connecting rod (not shown) is slidably arranged in a cylinder formed by the cylinder head and the cylinder block. It is installed. Further, a spark plug 19 is attached to the cylinder head so that the tip end portion is exposed to the combustion chamber 13.

  The engine intake pipe 2 is a fluid flow pipe that guides intake air filtered by an air cleaner (not shown) into the combustion chamber 13 via an intake passage in the intake manifold 14 and an intake port of the engine 1. In the engine intake pipe 2, an upstream opening end is airtight to an air cleaner case (not shown) that houses a filter element (not shown) or a throttle body (not shown) that houses a throttle valve (not shown). The downstream open end is hermetically connected to the intake manifold 14. An intake passage (fluid passage) formed in the engine intake pipe 2 is hermetically partitioned into a first air passage 21 and a second air passage 22 by a flat partition 20. The first air flow path 21 is provided on the upper layer side in the intake passage formed inside the engine intake pipe 2 and generates a tumble flow of the air-fuel mixture in the combustion chamber 13.

  The second air flow path 22 is provided on the lower layer side of the first air flow path 21 in the intake passage formed inside the engine intake pipe 2. The engine intake pipe 2 is attached with an electromagnetic fuel injection valve (injector) 23 for injecting fuel at an optimal timing to the intake port of the engine 1. In the present embodiment, the injector 23 is installed so that the injection hole is located in the vicinity of the intake air flow path from the air outlet portion of the first air flow path 21 through the upper layer side of the intake manifold 14 toward the intake port. Since the intake flow control valve 3 is housed inside the engine intake pipe 2, the engine intake pipe 2 constitutes a circular valve housing.

  The intake air flow control valve 3 controls the opening degree of the second air flow path 22 to positively flow the air flow into the first air flow path 21 to generate a tumble flow of the air-fuel mixture in the combustion chamber 13. This is a tumble flow control valve. The intake flow control valve 3 fully opens the air inlet portion of the first air passage 21 and fully closes the air inlet portion of the second air passage 22 when the valve is fully closed. Further, the intake flow control valve 3 fully opens both the air inlet portions of the first and second air flow paths 21 and 22 when the valve is fully opened. Thereby, the air inlet part of the 1st air flow path 21 is always opened.

  The intake flow control valve 3 includes a valve 24 formed in a semicircular shape by a metal material or a resin material, and a valve shaft 25 that holds the valve 24. The valve 24 is fastened and fixed to the valve holding portion of the valve shaft 25 by using a fastener 27 such as a fastening screw in a state where one end portion is inserted into a valve insertion hole 26 formed in the valve holding portion of the valve shaft 25. Has been. The valve shaft 25 is formed of a metal material or a resin material in the shape of a round shaft, and both end portions in the axial direction are rotatably supported by bearing support holes (not shown) of the engine intake pipe 2.

  The motor 5 is fastened and fixed to the main case 7 using a bracket 10 and a screw 11 while penetrating the main case 7. The motor 5 is a brushless DC motor including a rotor integrated with an output shaft (motor shaft) 29 and a stator disposed opposite to the outer peripheral side of the rotor. The rotor is provided with a rotor core having permanent magnets. The stator is provided with a stator core around which an armature coil (armature winding) is wound, and a cylindrical yoke 30 that covers the outer diameter side in the radial direction of the armature coil. Both end portions in the axial direction of the motor shaft 29 are provided so as to protrude from both end surfaces of the rotor core.

  A front side end portion (first end side end portion, left end portion in the drawing) of the motor shaft 29 in the axial direction is freely rotatable via a front side bearing on a cylindrical bearing case 31 assembled to the left end portion in the drawing of the yoke 30. Is pivotally supported. Further, the rear end (second end end, right end in the figure) of the motor shaft 29 in the axial direction is connected to a rear bearing on a cylindrical bearing case 32 formed integrally with the right end of the yoke 30 in the figure. It is pivotally supported via a shaft. The bearing case 31 is formed with an opening through which the front end of the motor shaft 29 in the axial direction passes. Instead of the brushless DC motor, a direct current (DC) motor with a brush or an alternating current (AC) motor such as a three-phase induction motor may be used.

  The gear reduction mechanism meshes with and rotates with a pinion gear 33 (motor side gear) 33 fixed to the outer periphery of the motor shaft 29 protruding from the bearing case 31 of the motor 5 to the front side (left side in the drawing) in the axial direction. The intermediate reduction gear 34, an output gear (valve side gear, non-motor side gear) 35 that meshes with and rotates with the intermediate reduction gear 34, and an output shaft 36 coupled to the output gear 35. The pinion gear 33 is formed in a cylindrical shape from a metal material, and is press-fitted to the outer periphery of the motor shaft 29. The intermediate reduction gear 34 is formed in an annular plate shape by a resin material, and is rotatably fitted to the outer periphery of a support shaft 37 that forms a rotation center. The intermediate reduction gear 34 is provided with a large-diameter gear 38 that meshes with the pinion gear 33 and a small-diameter gear 39 that meshes with the output gear 35.

  The output gear 35 is formed in an annular plate shape by a resin material, and is press-fitted to the outer periphery of the output shaft 36 that forms the rotation center. The output shaft 36 is formed in a cylindrical shape from a resin material, and drives and connects the output gear 35 of the gear reduction mechanism and the valve shaft 25 of the intake flow control valve 3. The output shaft 36 is formed in a round shaft bar shape from a metal material or a resin material, and the output gear 35 is coupled to one end side (right side in the figure) in the axial direction, and the other end side (left side in the figure) in the axial direction. A minus-shaped two-sided width portion 40 is formed in the upper part. The two-surface width portion 40 is a minus-character-shaped concave portion (see FIG. 5) formed on an end surface in the axial direction of the valve shaft 25 (a front end surface of a protruding portion protruding outward in the axial direction from the outer wall surface of the engine intake pipe 2). (Not shown) to prevent relative rotation between the valve shaft 25 and the output shaft 36.

  In the actuator case 6 constituted by the main case 7, the cover 8, the sub case 9, and the like, a motor housing space 41 for housing and holding the motor 5 and rotatably housing each gear of the gear reduction mechanism is provided. Is formed. The main case 7 is a resin case (case body) formed in a predetermined container shape by a resin material (for example, polybutylene terephthalate: PBT), and is a long cylindrical tube surrounding each gear of the motor 5 and the gear reduction mechanism. The wall portion 42 and a side wall portion 43 that are integrally provided on the right side (one end side) in the figure of the cylindrical wall portion 42 and are disposed to face the inner wall surface of the cover 8.

  An opening peripheral edge is provided at the opening end of the cylindrical wall portion 42. A plurality of fitting portions 44 for specifying the attachment position of the cover 8 are provided on the coupling end face of the opening peripheral edge portion of the cylindrical wall portion 42. These fitting portions 44 are concave fitting portions when a plurality of convex fitting portions are provided on the coupling end surface of the cover 8, and a plurality of concave fittings are formed on the coupling end surface of the cover 8. When a part is provided, it is set as a convex fitting part. Further, a plurality of projecting portions (attachment stays) 45 are extended from the outer periphery of the opening peripheral edge portion of the cylindrical wall portion 42 so as to protrude outward. Inside these protrusions 45, a metal collar 47 having an insertion hole 46 through which a fastener (not shown) such as a bolt for fastening and fixing the actuator case 6 to the outer wall surface of the engine intake pipe 2 is inserted. Is insert molded. A boss-like block portion 48 into which the shaft portion of the screw 11 is screwed is integrally formed on the inner periphery of the cylindrical wall portion 42. Note that a female screw portion that is screwed into a male screw portion provided on the outer periphery of the shaft portion of the screw 11 may be formed in the block portion 48 of the main case 7.

  The side wall 43 is provided with a recess 49 that rotatably supports the output shaft 36 of the gear reduction mechanism, and a recess 50 into which the support shaft 37 of the gear reduction mechanism is fitted by press fitting. The output gear 35 is slidably in contact with the inner wall surface around the recess 49. An intermediate reduction gear 34 is slidably in contact with the inner wall surface around the recess 50. The concave portions 49 and 50 are provided in the convex portion that protrudes to the right in the figure in the side wall portion 43 from the periphery. Further, the side wall 43 is provided with a partition wall 51 that divides the inside (the motor housing space 41) and the outside on the lower side of the recess 50 in the drawing. The partition wall 51 protrudes to the right side in the figure from the surrounding side wall part 43, and extends to the right side in the figure from the screw seat surface of the block part 48. A circular through hole (opening) 52 through which the motor 5 and the sub case 9 pass is provided at the bottom of the partition wall 51. The outer peripheral surface of the sub case 9 is in close contact with the hole wall surface (inner peripheral surface) of the through hole 52. Further, an annular case attachment seat 53 for attaching the sub case 9 is provided at the opening edge of the inner side of the through hole 52.

  The cover 8 is a resin cover formed in a predetermined oval shape by a resin material (for example, polybutylene terephthalate: PBT), and is provided so as to airtightly close the opening side of the cylindrical wall portion 42 of the main case 7. And has a coupling end surface for coupling to the coupling end surface of the opening peripheral portion of the cylindrical wall portion 42 by welding fixation or the like. The cover 8 is fitted with a boss-like block portion 55 formed with a through hole 54 that rotatably supports the output shaft 36 of the gear reduction mechanism and a support shaft 37 of the gear reduction mechanism by press-fitting or the like. And a recess 56. The through hole 54 is provided so as to communicate the inside (the motor accommodating space 41) and the outside. On the inner side of the block portion 55, a partially cylindrical guide portion 57 that surrounds the outer periphery of the output shaft 36 in an arc shape is formed. The guide portion 57 is formed with a notch portion 58 for preventing the intermediate reduction gear 34 from interfering with the large diameter gear 38.

  The sub case 9 is a metal case formed in a predetermined cylindrical shape with a metal material (for example, aluminum or steel) having excellent thermal conductivity, and for example, press forming (deep drawing) a flat metal thin plate. It consists of the cylindrical metal thin plate (cylindrical metal plate) deform | transformed by the bottomed cylinder shape by. The sub case 9 is provided so as to be separable from the main case 7, and the rear side end surface (in the axial direction) of the motor 5 in a state of passing through the through hole 52 formed in the partition wall 51 of the main case 7. One end surface (right end surface in the drawing) and the case mounting seat portion 53 of the main case 7 are sandwiched and held.

  In addition, the sub case 9 includes a cylindrical portion 61 in which at least a part of the outer peripheral surface of the cylindrical portion of the yoke 30 of the motor 5 (the rear side, the right side in the drawing) is in airtight contact (contact), and one axial direction of the motor 5. An end surface (the surface of the bearing case 32) has a bottom portion 62 that is airtightly in close contact (contact). The cylindrical portion 61 corresponds to the outer shape of the cylindrical portion of the yoke 30 of the motor 5 so that the outer peripheral surface of the cylindrical portion of the yoke 30 of the motor 5 is hermetically adhered (contacted) over the entire circumference in the circumferential direction. It is formed in a cylindrical shape. An opening peripheral edge is provided at the opening end of the cylindrical portion 61. From the outer periphery of the peripheral edge portion of the opening of the cylindrical portion 61, an annular plate-shaped flange portion 63 disposed opposite to the case mounting seat portion 53 of the main case 7 is extended so as to protrude toward the outer diameter side in the radial direction. Has been.

  Further, the bottom 62 is formed in a circular shape corresponding to the surface shape of the bearing case 32 of the motor 5 so that the surface of the bearing case 32 of the motor 5 is tightly adhered (contacted) over the entire surface. For this reason, the bottom 62 is provided with a concave portion 64 in which the rear side convex portion of the bearing case 32 is brought into close contact by press-fitting or the like. A motor housing hole 65 is formed in the subcase 9 to fit the motor 5 by press fitting. The motor housing hole 65 has a circular cross-sectional shape. Here, in this embodiment, at least a part (cylindrical portion 61, bottom portion 62) of the sub case 9 is protruded from the partition wall 51 of the main case 7 to the rear side (the right end side in the drawing) in the central axis direction of the motor 5. Thus, the outer wall surface of the sub case 9 is exposed to the air flowing around the actuator case 6.

  The bracket 10 is formed in a parallelogram shape by a metal material or a resin material, and has a circular fitting hole 66 in which the front side convex portion of the bearing case 31 of the motor 5 is fitted by a clearance fit or the like at the center portion. is doing. Further, at both ends in the central axis direction passing through the center of the fitting hole 66 of the bracket 10, mounting seat portions 67 that are fastened and fixed to the block portion 48 of the main case 7 are provided. These mounting seats 67 are formed with through holes (not shown) through which the shafts of the screws 11 pass. A circular motor load applying portion 68 corresponding to the surface shape of the bearing case 31 of the motor 5 is provided on the front surface (or the back surface) of the bracket 10.

  The motor load applying portion 68 of the bracket 10 has a first motor seat surface that is in close contact with the surface of the bearing case 31 of the motor 5, and the motor 5 is attached to the block portion 48 of the main case 7 using the fastening axial force of the screw 11. It is a load applying means for applying a load to the motor 5 in a direction in which the motor 5 is pressed against the second motor seat surface of the bottom 62 of the sub case 9 when tightening and fixing. Further, the motor load applying portion 68 of the bracket 10 has a first close contact with the flange portion 63 of the sub case 9 via the rubber seal 12 when the flange portion 63 of the sub case 9 is assembled to the case mounting seat portion 53 of the main case 7. A load applying unit that applies a load to the sub case 9 in a direction in which the surface (first seal seat surface) is pressed against the second contact surface (second seal seat surface) of the case mounting seat portion 53 of the main case 7.

  The screw 11 fastens and fixes the motor 5 to the block portion 48 of the main case 7, and constitutes a motor fastening means together with the bracket 10. The screw 11 has a bowl-shaped head portion formed with a plus-shaped groove portion with which a tool is engaged, and a shaft portion extended from the head portion. A male thread part for screwing into the block part 48 of the main case 7 is formed in the shaft part.

  The rubber seal 12 is made of a rubber-based elastic body, and has a first contact surface (first seal seat surface) of the flange portion 63 of the sub case 9 and a second contact surface (second seal seat) of the case mounting seat portion 53 of the main case 7. Is held in a state of being sandwiched between the two surfaces. The rubber seal 12 is formed in an annular shape so as to surround the through hole 52 of the main case 7. The rubber seal 12 compresses and deforms when receiving the fastening axial force (load) of the screw 11 when the motor 5 is fastened and fixed to the block portion 48 of the main case 7. This is a sealing member (for example, an O-ring) that hermetically seals a gap between the case 9 and the flange portion 63.

[Operation of Example 1]
Next, the operation of the intake air flow control device for an internal combustion engine according to the present embodiment will be briefly described with reference to FIGS.

  When the armature coil built in the motor 5 is energized, the motor shaft 29 starts to rotate. The rotational output of the motor 5 is transmitted from the pinion gear 33 fixed to the outer periphery of the motor shaft 29 to the large diameter gear 38 of the intermediate reduction gear 34 and further from the small diameter gear 39 of the intermediate reduction gear 34 to the output gear 35 in order. . Then, the rotation output of the motor 5 taken out from the motor actuator 4 from the output shaft 36 fixed to the output gear 35 is transmitted to the valve shaft 25 of the intake flow control valve 3, and the valve 24 of the intake flow control valve 3. Position adjustment, that is, the valve opening is adjusted.

  At this time, by energizing the armature coil built in the motor 5, heat generated in the armature coil (hereinafter referred to as heat of the motor 5) is transferred to the yoke 30 through the stator core around which the armature coil is wound. . The heat of the motor 5 transferred to the cylindrical portion of the yoke 30 and the bearing case 32 is the surface of the cylindrical portion 61 of the subcase 9 that is in close contact with the outer peripheral surface of the cylindrical portion of the yoke 30 and the surface of the bearing case 32 of the yoke 30. The heat is transferred to the bottom 62 of the subcase 9 that is in close contact with the bottom. In the motor actuator 4 of the present embodiment, at least a part of the cylindrical portion 61 of the sub case 9 and the entire bottom portion 62 are on the outer side (rear side) in the central axis direction of the motor 5 from the partition wall 51 of the main case 7. In other words, the outer wall surface of the sub case 9 protrudes from the partition wall 51 of the main case 7 to the outside. Therefore, the heat radiating surface of the sub case 9 made of a metal material that is more excellent in thermal conductivity than the resin material is exposed from the partition wall 51 of the main case 7 so that heat can be radiated. Thereby, the heat of the motor 5 transferred to the cylindrical portion 61 and the bottom portion 62 of the sub case 9 is efficiently radiated into the air flowing around the actuator case 6.

  Here, during the intake stroke of the engine 1, when the intake valve 16 is opened and the exhaust valve 17 is closed, if the piston 18 moves downward from the top dead center toward the bottom dead center, the piston 1 enters the combustion chamber 13 of the engine 1. A negative pressure is generated and the air-fuel mixture is sucked into the combustion chamber 13. At this time, the intake air filtered by the air cleaner flows into the intake passage of the engine intake pipe 2. The intake air flow is divided into an intake air flow passing through the first air flow path 21 and an intake air flow passing through the second air flow path 22 according to the valve opening degree of the valve 24 of the intake flow control valve 3. Then, the intake air that has passed through the second air flow path 22 flows into the intake manifold 14 from the air outlet portion of the second air flow path 22, and passes through the intake port formed in the intake manifold 14 and the cylinder head. It is sucked into the combustion chamber 13 via.

  On the other hand, the intake air that has passed through the first air flow path 21 passes from the air outlet portion of the first air flow path 21 to the upper layer portion of the intake manifold 14, the one side of the intake valve 16, and the upper layer portion of the intake port. 13 is inhaled. Further, in this embodiment, the fuel spray injected from the injection hole of the injector 23 is applied to the intake air flow toward one side of the intake valve 16. Thereby, when the intake valve 16 is opened, the injection hole of the injector 23 is utilized using the intake air flow that flows into the intake port from the air outlet portion of the first air passage 21 via the upper layer portion of the intake manifold 14. It is possible to promote atomization of the injected fuel spray (air assist function).

  When the intake valve 16 is opened, as shown in FIG. 2, the air outlet portion of the first air passage 21 passes through the upper layer portion of the intake manifold 14, one side of the intake valve 16, and the upper layer portion of the intake port. Thus, since the air-fuel mixture can be put into the combustion chamber 13, a vertical vortex flow (tumble flow) can be generated in the combustion chamber 13. Therefore, since a vertical vortex (tumble flow) for promoting combustion of the air-fuel mixture can be actively generated in the combustion chamber 13 of the engine 1, combustion is performed at a thin air-fuel ratio that is difficult to burn (lean combustion). This can improve fuel efficiency without degrading engine performance.

[Effect of Example 1]
As described above, in the intake flow control device for an internal combustion engine according to the present embodiment, the main case 7 is made of resin, so that the weight of the actuator case 6 is reduced, and the sub case 9 is metalized. The heat dissipation performance of the motor 5 is further improved by projecting at least a part of the cylindrical portion 61 of the case 9 and the entire bottom portion 62 from the partition wall 51 of the main case 7 to the outside in the central axis direction of the motor 5. Can do.

  Further, in the state in which the outer peripheral surface of the cylindrical portion of the yoke 30 of the motor 5 and the surface of the bearing case 32 of the yoke 30 are in close contact with the cylindrical portion 61 and the bottom portion 62 of the sub case 9 that have better thermal conductivity than the main case 7. The motor 5 is fitted and held in a motor housing hole 65 formed inside the sub case 9 by press fitting or the like. Then, by forming the cylindrical portion 61 and the bottom portion 62 of the sub case 9 into a cylindrical shape with a bottom using a cylindrical metal thin plate, the sub case 9 is easily elastically deformed in the plate thickness direction of the cylindrical portion 61 and the bottom portion 62. Yes. As a result, the degree of adhesion between the outer peripheral surface of the cylindrical portion of the yoke 30 of the motor 5 and the inner peripheral surface of the cylindrical portion 61 of the subcase 9 is increased, so that the outer peripheral surface of the cylindrical portion of the yoke 30 of the motor 5 is Since the inner peripheral surface of the cylindrical portion 61 is more closely attached, the heat dissipation performance of the motor 5 can be further improved.

  In addition, by forming the cylindrical portion 61 and the bottom portion 62 of the subcase 9 in a cylindrical shape with a bottom using a cylindrical metal thin plate, the subcase 9 is easily elastically deformed in the thickness direction of the cylindrical portion 61 and the bottom portion 62. Yes. Thereby, the outer peripheral surface of the yoke 30 of the motor 5 and the inner peripheral surface of the cylindrical portion 61 of the sub case 9 are more closely attached, and further, the surface of the bearing case 32 of the motor 5 and the bottom portion 62 of the sub case 9 are Since the inner wall surface is in closer contact with each other, the area where the motor 5 and the sub case 9 are in close contact with each other is greatly increased as compared with the prior art. For this reason, since the heat of the motor 5 can be efficiently transmitted by the sub case 9, the heat dissipation performance of the motor 5 can be further improved.

  Further, the motor 5 and the sub case 9 are fixed to the main case 7 through a through hole 52 formed in the partition wall 51 of the main case 7. That is, at least a part of the motor 5 and the sub case 9 (half or more in this embodiment) protrudes from the partition wall 51 of the main case 7 to the outside, so that the yoke 30 of the motor 5 is connected to the cylindrical portion 61 of the sub case 9 and It becomes easy to be exposed to the air flowing around the actuator case 6 via the bottom 62. Thereby, the heat dissipation performance of the motor 5 can be further improved. Therefore, by making the main case 7 resin, the motor case 5 is fitted and held in close contact with the sub case 9 that has better thermal conductivity than the main case 7 while reducing the weight of the actuator case 6. Thus, since the motor 5 can be efficiently cooled, performance deterioration of the motor 5 due to overheating of the motor 5 can be prevented. Moreover, since the motor performance can be improved, the quality of the motor actuator 4 can be improved.

  In addition, by forming the cylindrical portion 61 and the bottom portion 62 of the subcase 9 in a cylindrical shape with a bottom using a cylindrical metal thin plate, the subcase 9 is easily elastically deformed in the thickness direction of the cylindrical portion 61 and the bottom portion 62. Yes. Since the motor 5 is press-fitted into the motor housing hole 65 formed inside the sub case 9, the outer diameter of the cylindrical portion of the yoke 30 of the motor 5 and the motor housing hole of the cylindrical portion 61 of the sub case 9. The motor 5 can be easily press-fitted into the motor housing hole 65 of the sub case 9 without strict control of the dimensional accuracy with the inner diameter of 65. As a result, it is not necessary to strictly manage the dimensional accuracy between the outer diameter of the yoke 30 of the motor 5 and the inner diameter of the motor housing hole 65 of the sub case 9, thereby reducing the product cost.

  In addition, a sub case 9 that fits and holds the motor 5 in close contact is provided so as to be separable from the main case 7. The rubber seal 12 made of a rubber-based elastic body is held between the first contact surface of the flange portion 63 of the sub case 9 and the second contact surface of the case mounting seat 53 of the main case 7. Therefore, the difference in thermal expansion coefficient between the main case 7 and the sub case 9 can be absorbed. Thereby, the motor 5 can be held and fixed inside the main case 7 without rattling.

  In addition, the screw 11 that constitutes the motor fastening means with the bracket 10 presses the motor 5 against the second motor seat surface of the bottom 62 of the sub case 9 when the motor 5 is fastened and fixed to the main case 7. A function of applying a load to the motor 5 (load applying means), and when the flange portion 63 of the sub case 9 is assembled to the case mounting seat portion 53 of the main case 7, the flange portion 63 of the sub case 9 is inserted through the rubber seal 12. It also has a function (load applying means) for applying a load to the sub case 9 in a direction in which the first contact surface is pressed against the second contact surface of the case mounting seat 53 of the main case 7. Thereby, the fixing of the motor 5 to the main case 7 and the fixing of the sub case 9 to the main case 7 can be performed simultaneously by using one type of bracket 10 and the screw 11 for fastening and fixing the motor 5 to the main case 7. . Therefore, the motor 5 can be fastened and fixed to the main case 7 in a state in which the motor 5 is in close contact with the sub case 9 while reducing the number of parts and the number of assembling steps.

  The rubber seal 12 is compressed when a fastening axial force (tightening load) in a direction parallel to the central axis direction of the motor 5 is applied from the bracket 10 and the screw 11 through the first contact surface of the flange portion 63 of the sub case 9. Due to the deformation, an elastic repulsive force is generated in the rubber seal 12. The rubber seal 12 uses the elastic repulsive force to hermetically seal the gap between the first contact surface of the flange portion 63 of the sub case 9 and the second contact surface of the case mounting seat portion 53 of the main case 7. As a result, foreign matter such as water, dust, and dirt is introduced into the actuator case 6 from the gap between the first contact surface of the flange portion 63 of the sub case 9 and the second contact surface of the case mounting seat portion 53 of the main case 7. Never invade. As a result, foreign matter does not enter the motor 5 from the front side of the motor 5, so foreign matter is not caught between the rotor and the stator of the motor 5, that is, the motor 5 is not locked. The quality (control response, reliability, etc.) of the motor actuator 4 can be improved.

[Modification]
In the present embodiment, the intake flow control device for an internal combustion engine is configured so as to be able to generate a vertical vortex (tumble flow) for promoting combustion of the air-fuel mixture in the combustion chamber 13 of the engine 1. However, you may comprise so that generation | occurrence | production of the lateral vortex (swirl flow) which accelerates | stimulates the combustion of the engine 1 is attained. Further, the intake air flow control device for an internal combustion engine may be configured so as to be able to generate a squish vortex that promotes combustion of the engine 1. The motor actuator of the present invention may be applied to a motor actuator that drives an intake flow rate control valve such as an idle rotation speed control valve or a throttle valve. Further, the motor actuator of the present invention may be applied to a motor actuator that drives a passage switching door and an opening / closing door of a vehicle air conditioner. Moreover, you may apply to the motor actuator which drives the fluid pumping machine (For example, a fan, a compressor, a pump, etc.) which pressurizes fluid, such as gas and a liquid, and pumps.

  In this embodiment, a power transmission mechanism such as a gear reduction mechanism is installed between the motor shaft 29 of the motor 5 and the valve shaft 25 of the intake flow control valve 3, but the power transmission mechanism such as the gear reduction mechanism is abolished. The motor shaft 29 of the motor 5 and the valve shaft 25 of the intake flow control valve 3 may be directly connected. In this case, only the motor 5 is accommodated in the actuator case (motor case) 6, and the motor shaft 29 of the motor 5 passes through the actuator case 6 and the rotational output of the motor 5 is extracted to the outside. . Moreover, you may comprise separately the motor case which accommodates the motor 5, and the gear case which accommodates power transmission mechanisms, such as a gear reduction mechanism.

  In this embodiment, when the motor 5 is fastened and fixed to the main case 7 using the bracket 10 and the screw 11, the motor is connected to the flange portion 63 of the sub case 9 and the rubber seal 12 via the bearing case 32 of the yoke 30 of the motor 5. 5, a tightening load in a direction parallel to the central axis direction of the motor 5 is applied, but a bowl-shaped portion or a stepped portion is provided on the outer periphery of the cylindrical portion of the yoke 30 of the motor 5 so that the motor 5 is attached to the main case 7 on the bracket 10. When tightening and fixing using the screw 11, the flange 5 and the rubber seal 12 of the subcase 9 are tightened in a direction parallel to the central axis direction of the motor 5 through the flange portion or the step portion of the yoke 30 of the motor 5. A load may be applied. Further, the bracket 10 may be brought into direct contact with the flange-shaped or stepped portion of the yoke 30 of the motor 5.

(A) is the top view which showed the main structures of the motor actuator, (b) is sectional drawing which showed the whole structure of the motor actuator (Example 1). FIG. 1 is a schematic diagram showing a schematic configuration of an intake air flow control device for an internal combustion engine (Example 1). It is sectional drawing which showed the whole structure of the intake flow control apparatus for internal combustion engines (prior art). (A) is the front view which showed the resin housing of the intake flow control apparatus for internal combustion engines, (b) is AA sectional drawing of (a) (conventional technique). It is sectional drawing which showed the whole structure of the intake flow control apparatus for internal combustion engines (prior art).

Explanation of symbols

1 engine (internal combustion engine)
2 Engine intake pipe (valve body)
3 Intake flow control valve 4 Motor actuator 5 Motor 6 Actuator case (motor case)
7 Main case (resin case)
9 Sub case (metal case)
10 Bracket (Motor fastening means, load applying means)
11 Screw (Motor fastening means, load applying means)
12 Rubber seal (rubber-based elastic body, seal member)
30 Motor yoke 51 Main case partition wall 53 Main case case mounting seat 61 Cylindrical portion (cylinder portion) of the sub case
62 Subcase bottom 63 Subcase flange 68 Motor load application section (load application means)

Claims (9)

A motor actuator having a motor case that houses a motor therein,
The motor case has a main case to which the motor is fixed, and a sub case for holding the motor in a close contact state.
The main case is formed of a resin material,
The sub case is made of a metal material,
At least a part of the sub case is exposed on an outer surface of the main case or protrudes to the outside from the main case. The motor actuator according to claim 1,
The sub-case is made of a thin cylindrical plate with a bottom, and has a motor housing hole in which the motor is tightly fitted. The motor actuator according to claim 1 or 2,
The sub-case has a cylindrical portion that contacts at least a part of the outer periphery of the motor, and a bottom portion that contacts one end in the central axis direction of the motor. In the motor actuator according to any one of claims 1 to 3,
The main case has an opening in a partition wall that partitions the inside and the outside,
The motor actuator, wherein the motor penetrates the partition wall and is fixed to the main case. In the motor actuator according to any one of claims 1 to 4,
The motor actuator according to claim 1, wherein the sub case is provided so as to be separable from the main case. The motor actuator according to claim 5, wherein
A motor actuator comprising a rubber-based elastic body that is sandwiched and held between the main case and the sub case. In the motor actuator according to any one of claims 1 to 5,
A motor actuator comprising motor fastening means for fastening and fixing the motor to the main case. The motor actuator according to claim 7, wherein
The motor fastening means also serves as a load applying means for applying a load to the sub case in a direction in which the sub case is pressed against the main case when the sub case is assembled to the main case. Actuator. The motor actuator according to claim 8, wherein
A rubber-based elastic body that is sandwiched and held between the main case and the sub case,
The motor-based actuator is characterized in that the rubber-based elastic body is a seal member that compresses and deforms when the load is applied to hermetically seal a gap between the main case and the sub case.

Images