JP2007315232A - Air control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a system failure from occurring by preventing the inside of a secondary air supply system from being abnormally heated when the valve opening of the poppet valve of a secondary air control valve fails. <P>SOLUTION: The final gear of a power transmission device for driving the poppet valve is composed of a first and a second rotating bodies 11, 12 which are separated from each other. The motor side first rotating body 11 is formed of a resin material lower in melting point than the material (metal material) of the valve side second rotating body 12. When the valve opening of the poppet valve fails due to the failure of an electric motor or the power transmission device, the heat of hot exhaust gases flowing into an air flow passage in a housing to the fitted projection 64 of the fitted tube part 62 of the first rotating body 11 to thermally deform (melting loss) and disconnect the fitted tube part 62 of the motor side first rotating body 11 from the fitted tube part 72 of the valve side second rotating body 12. Consequently, the poppet valve is closed by the spring force of a torsion spring. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an air control valve that opens and closes an air flow path formed inside a housing, and particularly relates to a secondary air control valve incorporated in a secondary air supply system.

[Conventional technology]
Conventionally, secondary air generated in the secondary air flow path pipe at the time of engine start is led to a three-way catalytic converter for purifying exhaust gas flowing out from the combustion chamber of the engine to promote warm-up of the three-way catalyst 2 Secondary air supply systems are known. In this case, the electric air pump and the secondary air control valve are connected via a secondary air passage pipe, and the secondary air control valve and the engine exhaust pipe are connected via a secondary air passage pipe. Here, as the secondary air control valve, an electromagnetic on-off valve that opens and closes an air flow path formed inside the housing, and a check valve that prevents exhaust gas from flowing back to the electric air pump side or the electromagnetic on-off valve side A combination valve is used (see, for example, Patent Document 1). The housing of the secondary air control valve is connected between the secondary air flow pipes.

[Prior art]
Here, in the Japanese Patent Application No. 2005-209613 (filed on July 20, 2005: Comparative Example 1), the present applicant has adopted an electric motor as a power source of a valve body (valve) of the secondary air control valve 2 The next air supply system was filed. As shown in FIG. 7, the valve driving device that opens the valve is a gear having an electric motor 102 that generates a driving force for driving the valve 101, a motor gear 103, an intermediate reduction gear 104, and a final gear 105. And a speed reduction mechanism. Then, the pinion gear 107 provided on the final gear 105 and the rack teeth 111 provided on the valve shaft 110 of the valve 101 are engaged with each other, and the final gear 105 is rotationally driven by the electric motor 102, thereby rotating the final gear 105. The movement is converted into a linear movement of the valve shaft 110 and the valve 101 is driven to open.

[Defects of prior technology]
However, in the final gear 105 of Comparative Example 1, the final reduction gear 106 that meshes with the intermediate reduction gear 104 and receives the driving force of the electric motor 102 is the same as the pinion gear 107 that transmits the valve closing force of the spring 109 to the valve shaft 110. (Integrated structure), when electric power is supplied to the electric motor 102 and the valve 101 is opened, if the electric motor 102 fails (locks) or the gear reduction mechanism fails (locks) for some reason, the valve There is a possibility that 101 may not move while being open.

Here, in the secondary air control valve incorporated in the secondary air supply system, the secondary pulsation from the junction of the engine exhaust pipe and the secondary air flow pipe is caused by the exhaust pulsation caused by opening and closing of the exhaust valve of the engine. There is a possibility that a high-temperature fluid (for example, high-temperature exhaust gas having a temperature of 500 ° C. or higher) flows back into the air control valve housing. Therefore, when a failure occurs in the electric motor 102 or the gear reduction mechanism and the valve 101 is kept open, the secondary air supply system on the electric air pump side passes through the passage hole formed in the valve seat. High-temperature exhaust gas repeatedly flows into the interior for a long time. For this reason, the inside of the secondary air supply system may become abnormally hot and the system may break down.
JP 2002-272080 A (page 1-5, FIG. 1)

  An object of the present invention is to provide an air control valve capable of preventing a high-temperature fluid from flowing into an air flow path inside a housing when a valve opening failure occurs. Further, when the valve fails to open due to a failure of the power source or the power transmission mechanism, the first coupling of the first rotating body on the power source side is performed using the heat of the high-temperature fluid flowing into the air flow path inside the housing. An object of the present invention is to provide an air control valve capable of closing a valve by a biasing force of a spring by removing the coupling between the first coupling portion and the second coupling portion of the second rotating body on the valve side.

  According to the first aspect of the present invention, when the air flow formed in the housing is opened by transmitting the driving force generated in the power source to the valve of the air control valve, the power source or the power transmission mechanism If a failure occurs, the valve of the air control valve is kept open. If the valve fails to open due to such a power source or power transmission mechanism failure, the valve of the air control valve is exposed to the high temperature fluid flowing into the air flow path formed inside the housing, and the temperature of the valve itself Rises to a high temperature. Then, the heat of the high-temperature fluid is transmitted from the valve to the second rotating body, and further transmitted from the second coupling portion provided in the second rotating body to the first coupling portion provided in the first rotating body.

Here, the first coupling part of the first rotating body on the power source side is formed of a material having a melting point lower than that of the second coupling part of the second rotating body on the valve side. When the temperature of the first coupling portion itself is increased to a high temperature, the first coupling portion is thermally deformed before the second coupling portion. Along with the thermal deformation of the first coupling part, the coupling force between the first coupling part and the second coupling part is weakened, so the first coupling part of the first rotating body and the second coupling part of the second rotating body The bond breaks.
Thereby, the valve of the air control valve is closed by the biasing force of the spring, and the air flow path formed inside the housing is closed. Therefore, the flow of the high-temperature fluid into the air flow path formed inside the housing is stopped, and an abnormal temperature rise inside the housing can be prevented.
In addition, when this air control valve is incorporated in, for example, a secondary air supply system, it is possible to prevent the flow of high-temperature fluid into the air flow path inside the housing when the valve opens and fails. The flow of high-temperature fluid into the interior stops, and abnormal temperature rise inside the system can be prevented. Thereby, a system failure can be prevented.

According to the second aspect of the present invention, at least the first coupling portion of the first rotating body may be formed of a material having lower rigidity or strength against heat than the material of the second coupling portion.
According to invention of Claim 3, you may form at least 1st coupling | bond part of a 1st rotary body with the material whose melting | fusing point is lower than the material of a 2nd rotary body.
According to the invention described in claim 4, at least the first coupling portion of the first rotating body may be formed of a resin material, and at least the second coupling portion of the second rotating body is You may form with a metal material.

According to the fifth aspect of the invention, the valve of the air control valve can be pressed against the valve seat by applying the load of the spring to the valve of the second rotating body or the air control valve. Thereby, the valve of the air control valve is seated on the valve seat and the air flow path formed in the housing is closed.
According to the sixth aspect of the present invention, the spring is constituted by the coil portion disposed so as to surround the shaft of the power transmission mechanism in a spiral manner and the two coil terminals drawn from both ends of the coil portion. You may do it. One of the two coil terminals is locked to the second rotating body, and the other coil terminal of the two coil terminals is locked to the housing, so that the valve is fully closed. You may comprise so that it may urge in the direction returned to a position.
According to the seventh aspect of the present invention, the two first and second rotating bodies may be disposed so as to surround the periphery of one shaft of the power transmission mechanism. As a result, the two first and second rotating bodies can be easily arranged on the same axis.

According to the eighth aspect of the present invention, the heat of the high-temperature fluid that flows into the air flow path inside the housing when the valve fails to open due to the failure of the power source or the power transmission mechanism, the valve of the air control valve, It is transmitted to the second rotating body and the first rotating body. As a result, when the temperature of the convex portion of the first coupling portion of the first rotating body rises to a high temperature, the convex portion of the first coupling portion is thermally deformed before the second coupling portion. As the convex portion is thermally deformed, the coupling force between the convex portion of the first coupling portion and the concave portion of the second coupling portion is weakened, so that the coupling between the convex portion and the concave portion is released.
Thereby, the valve of the air control valve is closed by the biasing force of the spring, and the air flow path formed inside the housing is closed. Therefore, the flow of the high-temperature fluid into the air flow path formed inside the housing is stopped, and an abnormal temperature rise inside the housing can be prevented.

According to the ninth aspect of the present invention, the heat of the high-temperature fluid flowing into the air flow path inside the housing when the valve opens due to the failure of the power source or the power transmission mechanism is generated from the valve of the air control valve. The first coupling portion provided in the first rotating body is transmitted to the second rotating body and further passes through the boundary surface between the two first and second rotating bodies from the second coupling portion provided in the second rotating body. It is transmitted to.
Here, the second coupling part is insert-molded inside the first coupling part, and the first coupling part of the first rotating body on the power source side is the second coupling part of the second rotating body on the valve side. Since it is made of a material having a melting point lower than that of the material, when the temperature of the first coupling portion itself of the first rotating body rises and becomes high, the first coupling portion is thermally deformed before the second coupling portion. To do. With the thermal deformation of the first coupling portion, the first coupling portion of the first rotating body is peeled off from the second coupling portion of the second rotating body.

  That is, the first coupling portion of the first rotating body is connected to the second coupling body of the second rotating body at the boundary surface between the two first and second rotating bodies by the heat of the high-temperature fluid flowing into the air flow path inside the housing. Peel from the part. Thereby, since the coupling force between the first coupling portion and the second coupling portion is weakened, the coupling between the first coupling portion of the first rotating body and the second coupling portion of the second rotating body is released. Thereby, the valve of the air control valve is closed by the biasing force of the spring, and the air flow path formed inside the housing is closed. Therefore, the flow of the high-temperature fluid into the air flow path formed inside the housing is stopped, and an abnormal temperature rise inside the housing can be prevented.

  The best mode for carrying out the present invention is that the interior of a system such as a secondary air supply system incorporating an air control valve is used even when the valve has failed to open due to a failure of a power source or a power transmission mechanism. The purpose of preventing abnormal system temperature rise and preventing system failure is to prevent the heat of the high-temperature fluid flowing into the air flow path inside the housing when the valve opens due to a power source or power transmission mechanism failure. The valve is closed by the biasing force of the spring by removing the coupling between the first coupling part of the first rotating body on the power source side and the second coupling part of the second rotating body on the valve side. It was realized.

[Configuration of Example 1]
1 to 4 show Embodiment 1 of the present invention. FIG. 1 is a view showing the entire structure of a secondary air control valve. FIG. 2 is a view showing the entire structure of a motor actuator. 3 is a view showing the main structure of the secondary air control valve.

  The secondary air control valve of the present embodiment is a three-way device for generating secondary air generated in a secondary air passage pipe (fluid passage pipe) when an internal combustion engine (hereinafter referred to as an engine) such as a gasoline engine is started. It is incorporated in a secondary air supply system (secondary air supply device) that leads to a catalytic converter (not shown) to promote warm-up of the three-way catalyst. This secondary air supply system is mounted in an engine room of a vehicle such as an automobile, for example, and an electric air pump (not shown) and a secondary air control valve are connected via a secondary air flow pipe. The secondary air control valve and the engine exhaust pipe are connected via a secondary air flow path pipe.

  The secondary air control valve is an air switching valve that opens and closes a secondary air passage (fluid passage) formed inside the housing (fluid passage on-off valve, air passage on-off valve: hereinafter referred to as ASV). And a non-return valve (not shown) for preventing fluid such as exhaust gas from flowing back to the ASV side from the junction of the secondary air passage pipe and the engine exhaust pipe It is a control valve (combination valve module). The check valve has a thin-film reed valve that is opened by the pressure of the secondary air discharged from the electric air pump.

  The ASV includes a poppet valve 1 that performs a reciprocating linear motion in the central axis direction, and a valve seat (valve seat portion) 2 on which the poppet valve 1 is seated. Note that the poppet valve 1 of this embodiment is incorporated in the housing 3. Here, the secondary air supply system of the present embodiment is an engine control unit (hereinafter referred to as ECU) that electronically controls the electric motor 4 that is the power source of the electric air pump and the secondary air control valve based on the operating state of the engine. (Not shown).

  Here, the ECU is provided with a microcomputer having a well-known structure configured to include functions such as a CPU for performing control processing and arithmetic processing, various programs, and a storage device (memory such as ROM and RAM) for storing data. It has been. This ECU controls the rotational motion of the electric motor 4 by adjusting the power supplied to the electric motor 4 based on a control program stored in the memory when the ignition switch is turned on (IG / ON). Control unit. The ECU detects the exhaust gas temperature with an exhaust temperature sensor (not shown) when the engine is started. When the exhaust gas temperature is equal to or lower than a predetermined value, the ECU supplies electric power to the electric motor 4 to open the ASV. At this time, since electric power is also supplied to the electric air pump, secondary air is generated in the secondary air flow path formed inside the secondary air flow path pipe.

  The ASV poppet valve 1 is integrally formed of a resin material and is movably accommodated inside the housing 3. The poppet valve 1 constitutes a valve body (a valve body of a secondary air control valve) that is seated and removed from the valve seat 2 to close and open the flow path hole (ASV valve opening) 5. The poppet valve 1 has a flange-shaped valve head (valve head, valve head) 6 and a cylindrical valve shaft (valve shaft, valve shaft, valve shaft) 7 so as to reciprocate in the axial direction. It is configured. Alternatively, the poppet valve 1 in which the valve head 6 and the valve shaft portion 7 are manufactured separately and the valve head portion 6 and the valve shaft portion 7 are coupled so as to be integrally operable thereafter may be used. .

  In the present embodiment, the back surface side (valve face) of the valve head 6 of the poppet valve 1 is configured to be seated on the lower end surface of the valve seat 2 in the drawing (opening peripheral edge portion of the flow path hole 5). The valve head 6 is provided in a bowl shape so that the outer diameter thereof is larger than that of the valve shaft 7 at one end (the lower end in the figure) of the valve shaft 7 in the central axis direction. Around the valve head 6, a rubber-based elastic body (seal rubber) 6 a for improving the sealing performance (airtightness) with the valve seat 2 when the valve head 6 is seated on the valve seat 2. Is mounted using means such as baking.

  Further, the inside of one side (the lower side in the figure) of the valve shaft portion 7 of the poppet valve 1 in the central axis direction is hollow. A rack in which a plurality of teeth are formed on the other side (upper side in the figure) of the valve shaft 7 of the poppet valve 1 so as to repeat unevenness along the center axis of the valve shaft 7. Teeth (rack) 13 are provided. The rack teeth 13 constitute one component of the movement direction conversion mechanism described later. The poppet valve 1 has a space (communication path) formed between the check valve and the valve seat 2 when the valve head 6 is separated (lifted) from the valve seat 2, that is, when the valve is opened. In the middle of 17), the valve head 6 is configured to be held (arranged). That is, the poppet valve 1 is configured to move to one side (the check valve side) in the central axis direction of the poppet valve 1 when the valve is opened.

  Here, a circular flow path hole 5 through which secondary air passes is formed inside the valve seat 2. The valve seat 2 may be configured so as to be integrally coupled to the inside of the housing 3 after being manufactured separately from the housing 3. In this embodiment, the flow passage hole is formed from an inlet portion (hereinafter referred to as an inlet port) 15 of the inlet pipe 14 formed integrally with the housing 3 through the inside of the housing 3 (fluid introduction flow passage 16). The secondary air flows into 5. A communication path 17 is formed at the outlet of the housing 3. The communication path 17 communicates the flow path hole 5 of the ASV with a fluid passage opening (not shown) that is opened and closed by a reed valve of a check valve. A connecting portion 19 that is connected to the check valve housing is formed at the opening edge of the outlet portion of the housing 3. In this embodiment, the air flow path formed in the housing is formed by the flow path hole 5 formed in the valve seat 2, the fluid introduction flow path 16 and the communication path 17 formed in the housing 3. Forming.

  Here, as shown in FIGS. 1 to 4, the valve driving device (motor actuator) for driving the ASV poppet valve 1 in the valve opening operation direction (or valve closing operation direction) is a resin material (for example, polyphenylene sulfide: Power including a housing 3 integrally formed by PPS or the like, an electric motor 4 operated by electric power, and a movement direction conversion mechanism for transmitting the driving force of the electric motor 4 to the valve shaft portion 7 of the poppet valve 1 Transmission mechanism (pinion gear 8, intermediate reduction gear 9, final gear, rack teeth 13, etc.) and torsion spring 10 that urges the valve head 6 of the poppet valve 1 in the valve closing operation direction (side closing the flow path hole 5). And a motor torque transmission device.

  The housing 3 accommodates the electric motor 4 and the power transmission mechanism with a gear cover (not shown). A resin mold member 21 is assembled to the upper end of the housing 3 in the figure. The resin mold member 21 is integrally formed of a resin material (electrically insulating resin, for example, polybutylene terephthalate containing 30% glass fiber: PBTG30), and is provided on the vehicle side (ECU side) front end side of the wire harness. A male connector that is mechanically connected to the female connector is integrally formed. The male connector includes a motor drive circuit built in the ECU and a terminal 23 of the electric motor 4 by inserting a female connector provided on the distal end side of the vehicle-side wire harness into the connector shell 22 of the male connector. , 24 are electrically connected. The vehicle-side wire harness is a bundle of conductive wires with an insulation protection tube on the outer periphery, and these conductive wires are electrically connected to respective female terminals provided in the female connector.

  Here, in the housing 3 of the present embodiment, a cylindrical valve guide 26 having an axial hole 25 formed therein, a motor case 29 having a motor accommodation hole 27 formed therein, and a spring between the gear cover. A cylindrical gear box 32 and the like forming a gear housing chamber 31 including the housing chamber are integrally formed. The valve guide 26 slidably supports the valve shaft portion 7 of the poppet valve 1 inside the axial hole 25. And, between the outer periphery of the valve shaft portion 7 of the poppet valve 1 and the inner periphery of the valve guide 26 of the housing 3 on the fluid introduction flow path side (open end side), foreign matter (dust) to the sliding portion of the power transmission mechanism. Etc.) and an annular dust seal 33 for preventing leakage of secondary air from the fluid introduction channel 16 is mounted. Further, the motor case 29 of the housing 3 accommodates the electric motor 4 in the motor accommodation hole 27.

  The gear box 32 constitutes a power transmission mechanism case together with the gear cover. This gear box 32 rotatably accommodates each gear (pinion gear 8, intermediate reduction gear 9, final gear) that constitutes a component of the gear reduction mechanism in the gear accommodation chamber 31. In the bottom wall surface of the gear box 32, the motor insertion opening of the motor housing hole 27 of the motor case 29 is opened. Further, the gear box 32 has a cylindrical spring guide so as to surround the coil outer diameter side of the cylindrical coil portion 50 of the torsion spring 10 spirally disposed around the final gear of the gear reduction mechanism. ing. The inner peripheral portion (inner wall surface) of this spring guide functions as a spring outer peripheral guide that holds the coil outer diameter side of the cylindrical coil portion 50 of the torsion spring 10.

  The electric motor 4 is a brushless direct current (DC) motor comprising a rotor integrated with a motor shaft (motor shaft) 41 and a stator arranged opposite to the outer periphery of the rotor. The rotor has a permanent magnet (magnet). The stator is provided with a stator core around which an armature coil (armature winding) is wound and a cylindrical yoke. The pair of motor power supply terminals 42 provided so as to protrude outward from the front end surface of the motor housing of the electric motor 4 electrically connect the coil terminal wire of the armature coil of the electric motor 4 and the terminal 24. ing. When the electric motor 4 is energized by the ECU, the motor shaft 41 rotates in the forward rotation direction (valve opening direction) and the reverse rotation direction (valve closing direction). Here, the front end portion (small-diameter convex portion, bearing holder) of the electric motor 4 is fit in the motor fitting hole 44 of the metal plate 43. The metal plate 43 is fastened and fixed to the peripheral edge of the opening of the motor insertion port of the motor case 29 of the housing 3 by using a screw 45 such as a fastening screw. 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 power transmission mechanism is a torque transmission mechanism that transmits the driving force (rotational torque, motor output shaft torque: hereinafter referred to as motor torque) of the electric motor 4 to the valve shaft portion 7 of the poppet valve 1. It comprises a gear reduction mechanism that reduces the rotational speed (motor speed) of the motor shaft 41 to a predetermined reduction ratio. The gear reduction mechanism includes a cylindrical pinion gear (motor-side gear) 8 fixed to the outer periphery of the motor shaft 41 of the electric motor 4, and an intermediate reduction gear (not shown) that meshes with the pinion gear 8 and transmits motor torque from the pinion gear 8. (Intermediate gear) 9, a final gear that meshes with the intermediate reduction gear 9 to transmit motor torque from the intermediate reduction gear 9, and rack teeth 13 provided on the valve shaft portion 7 of the poppet valve 1. .

  The pinion gear 8 is disposed coaxially with the motor shaft 41 of the electric motor 4 (for example, on the same axis). The pinion gear 8 is a rotating body that rotates relative to the gear box 32 of the housing 3 and that rotates around the axis of the motor shaft 41 of the electric motor 4. The pinion gear 8 is integrally formed of a metal material, and has a cylindrical small diameter cylindrical portion (cylindrical portion) disposed so as to surround the motor shaft 41. The cylindrical portion of the pinion gear 8 is fixed to the outer periphery of the motor shaft 41 of the electric motor 4 by press fitting or the like, and rotates integrally with the motor shaft 41 of the electric motor 4. A plurality of convex teeth are formed in the entire circumferential direction on the outer periphery of the cylindrical portion of the pinion gear 8. Here, the motor shaft 41 of the electric motor 4 is a shaft extending in the motor axial direction of the electric motor 4 (and the axial direction parallel to the axial direction of the gear box 32 of the housing 3), and the pinion gear that forms the rotation center of the pinion gear 8. A shaft (first gear shaft) is configured. The motor shaft 41 is a rotating shaft that rotates relative to the gear box 32 of the housing 3.

  The intermediate reduction gear 9 is arranged in parallel with the motor shaft 41 of the electric motor 4 and has an intermediate reduction gear shaft 46 in a direction orthogonal to the central axis direction of the valve shaft portion 7 of the poppet valve 1. . Here, the intermediate reduction gear shaft 46 is a support shaft extending in the axial direction parallel to the motor axial direction of the electric motor 4 and the axial direction of the gear box 32 of the housing 3, and is a second shaft that forms the rotation center of the intermediate reduction gear 9. It constitutes the gear shaft. The intermediate reduction gear shaft 46 is integrally formed of a metal material and is fixed to the gear box 32 of the housing 3. That is, one end of the intermediate reduction gear shaft 46 in the axial direction is press-fitted and fixed in a fitting recess formed in the gear cover. The other end portion of the intermediate reduction gear shaft 46 in the axial direction is press-fitted and fixed in a fitting recess formed in the gear box 32 of the housing 3.

  The intermediate reduction gear 9 is a rotating body that rotates relative to the gear box 32 of the housing 3 and that rotates around the axis of the intermediate reduction gear shaft 46. The intermediate reduction gear 9 is integrally formed of a resin material (for example, polyamide resin: PA), and has a cylindrical small diameter cylindrical portion (cylindrical portion) disposed so as to surround the intermediate reduction gear shaft 46. have. The cylindrical portion of the intermediate reduction gear 9 is rotatably fitted to the outer periphery of the intermediate reduction gear shaft 46 and rotates around the central axis of the intermediate reduction gear shaft 46. A large-diameter gear 47 that meshes with the pinion gear 8 is formed at one end in the axial direction of the cylindrical portion of the intermediate reduction gear 9. The large-diameter gear 47 is a plurality of convex teeth formed on the outer periphery of the cylindrical portion of the intermediate reduction gear 9 in the entire circumferential direction. A small-diameter gear (not shown) that meshes with the final gear is formed on the other end side in the axial direction of the cylindrical portion of the intermediate reduction gear 9. The small-diameter gear is a plurality of convex teeth formed on the outer circumference of the cylindrical portion of the intermediate reduction gear 9 in the entire circumferential direction.

  As shown in FIGS. 2 and 3, the torsion spring 10 of the present embodiment is disposed around the final gear shaft 49 of the final gear so as to be elastically deformable, and the rotational position of the final gear is set to the initial position (default position). ) Is a coil spring (return spring) that is urged in the direction to return to (). Further, when the final gear (the two first and second rotating bodies 11 and 12) rotates in the normal rotation direction (opening direction of the poppet valve 1), the torsion spring 10 opposes the final gear with respect to the normal rotation direction. The torsional elastic force that rotates in the direction (reverse direction) is accumulated. The torsion spring 10 always has a function as a spring load applying means for applying a spring load to the final gear in a direction in which the poppet valve 1 is pressed against the opening peripheral portion (valve seat 2) of the flow path hole 5. is doing.

  The torsion spring 10 has a cylindrical coil portion 50 disposed in a spring accommodating space formed between the outer periphery of the final gear, particularly the first rotating body 11 and the inner peripheral portion of the spring guide of the housing 3. is doing. The cylindrical coil portion 50 is disposed along the axial direction of the final gear so as to spirally surround the first rotating body 11 inside the spring accommodating space. A pair of first and second coil terminals 51 and 52 are respectively provided on both sides in the axial direction of the cylindrical coil portion 50 of the torsion spring 10 and held by the flange portion 57 of the final gear and the gear box 32 of the housing 3. It has been. The first coil terminal 51 is formed in an L shape and is locked to a first spring hook (first locking portion) 53 provided on the second rotating body 12 of the final gear. The second coil terminal 52 is formed in an L shape and is locked to a second spring hook (second locking portion) 54 provided on the inner peripheral portion of the gear box 32 of the housing 3. .

  As shown in FIGS. 1 to 4, the final gear is arranged in parallel with the motor shaft 41 of the electric motor 4, and finally moves in a direction orthogonal to the central axis direction of the valve shaft portion 7 of the poppet valve 1. A gear shaft 49 is provided. Here, the final gear shaft 49 corresponds to the shaft of the power transmission mechanism of the present invention, and is a support shaft extending in the axial direction parallel to the motor axial direction of the electric motor 4 and the axial direction of the gear box 32 of the housing 3. There is a third gear shaft that forms the center of rotation of the final gear. The final gear shaft 49 is integrally formed of a metal material and is fixed to the gear box 32 of the housing 3. That is, one end portion of the final gear shaft 49 in the axial direction is press-fitted and fixed in a fitting recess formed in the gear cover. The other end portion of the final gear shaft 49 in the axial direction is press-fitted and fixed in a fitting recess formed in the gear box 32 of the housing 3. Further, the final gear is constituted by two first and second rotating bodies 11 and 12 that perform rotational movement about the axis of the final gear shaft 49.

  The first rotating body 11 itself constitutes the final reduction gear, and is disposed on the motor side of the second rotating body 12 on the power transmission path of the power transmission mechanism (gear speed reduction mechanism). It rotates relative to the box 32. The first rotating body 11 is integrally formed of a resin material (for example, polyamide resin: PA) having a lower rigidity or strength against heat than the material of the second rotating body 12 and a lower melting point than the material of the second rotating body 12. Is formed. The first rotating body 11 has a cylindrical small-diameter cylindrical portion (cylindrical portion) 56 that is disposed so as to surround the periphery of the final gear shaft 49 and has an axial hole 55 formed therein. . The small-diameter cylindrical portion 56 of the first rotating body 11 is rotatably fitted on the outer periphery of the final gear shaft 49 and rotates around the central axis of the final gear shaft 49.

  An annular plate-like flange portion 57 projects from the outer periphery of the small diameter cylindrical portion 56 to the outer diameter side in the radial direction of the final gear at one end portion in the axial direction of the small diameter cylindrical portion 56 of the first rotating body 11. Are integrally formed. A final reduction gear portion 59 that is larger than the outer diameter of the small diameter cylindrical portion 56 and meshes with the small diameter gear of the intermediate reduction gear 9 is formed at the maximum outer diameter portion of the flange portion 57. The final reduction gear portion 59 is a plurality of convex teeth formed in an arc shape on a part of the outer periphery of the maximum outer diameter portion of the flange portion 57. The plate thickness of the final reduction gear portion 59 (the dimension in the axial direction of the first rotating body 11) is thicker than the flange portion 57.

  In addition, a cylindrical fitting tube portion (first shape) in which a fitting hole 61 having an inner diameter larger than that of the axial hole 55 is formed at the other end portion in the axial direction of the small diameter tube portion 56 of the first rotating body 11. 1 coupling portion) 62 is integrally formed. The fitting cylinder portion 62 extends so as to cover the periphery of the second coupling portion of the second rotating body 12, and is a circle disposed at the bottom of the fitting hole 61 so as to face the coupling end surface of the second rotating body 12. An annular coupling end face 63 is formed. In this embodiment, the final gear shaft 49 passes through the axial hole 55 and the fitting hole 61. A plurality of fitting convex portions 64 that are engaged with the surface of the second coupling portion of the second rotating body 12 are integrally formed on the inner peripheral surface of the fitting cylindrical portion 62 of the first rotating body 11. Has been. These fitting convex portions 64 are spaced from the inner peripheral surface of the fitting cylinder portion 62 at the final gear shaft side (first rotation) at a predetermined interval (equal interval: for example, 120 ° interval) in the circumferential direction of the fitting cylinder portion 62. It is provided in a streak shape so as to protrude toward the central axis side of the body 11. The plurality of fitting projections 64 extend from the opening end of the fitting cylinder portion 62 toward the bottom of the fitting hole 61 in the axial direction of the fitting cylinder portion 62 of the first rotating body 11.

  Further, the outer peripheral portions of the small diameter cylindrical portion 56 and the fitting cylindrical portion 62 of the first rotating body 11 function as a spring inner peripheral guide that holds the coil inner diameter side of the cylindrical coil portion 50 of the torsion spring 10. Further, the small-diameter cylindrical portion 56 and the fitting cylindrical portion 62 of the first rotating body 11 are cylinders that elastically deformably accommodate the cylindrical coil portion 50 of the torsion spring 10 between the inner peripheral portion of the spring guide of the housing 3. A spring-shaped spring accommodating space is formed. The flange portion 57 includes a cylindrical gap between the outer periphery of the small diameter cylindrical portion 56 and the fitting cylindrical portion 62 of the first rotating body 11 and the inner diameter of the cylindrical coil portion 50 of the torsion spring 10, and the outside of the spring accommodating space. Three slits 65 are formed so as to communicate with the outside of the final gear in the present embodiment in the axial direction of the flange portion 57.

  The second rotating body 12 is disposed coaxially with the first rotating body 11 (for example, on the same axis). The second rotating body 12 itself constitutes an output gear, and is disposed on the valve side (particularly on the most valve side) of the first rotating body 11 on the power transmission path of the power transmission mechanism (gear reduction mechanism). Then, it rotates relative to the gear box 32 of the housing 3. The second rotating body 12 is integrally formed of a metal material, is disposed so as to surround the periphery of the final gear shaft 49, and has a cylindrical fitting tube in which an axial hole 71 is formed. A portion (cylindrical portion) 72 is provided. The fitting cylinder portion 72 of the second rotating body 12 is rotatably fitted to the outer periphery of the final gear shaft 49 and rotates around the central axis of the final gear shaft 49. In the present embodiment, the final gear shaft 49 passes through the inside of the axial hole 71.

  An annular coupling end surface 73 is formed at one end of the fitting cylinder portion 72 of the second rotating body 12 in the axial direction so as to face the coupling end surface 63 of the first rotating body 11. Further, the fitting cylinder portion 72 of the second rotating body 12 constitutes a second coupling portion that is fitted into the fitting hole 61 of the first rotating body 11 and is coupled to the fitting cylinder portion 62. A plurality of fitting recesses 74 that engage with the plurality of fitting protrusions 64 are integrally formed on the outer peripheral surface (front surface) of the fitting cylinder portion 72. These fitting concave portions 74 are provided in a streak shape at positions corresponding to the fitting convex portions 64 on the outer peripheral surface of the fitting cylindrical portion 72. And the final gear of a present Example engages the fitting convex part 64 of the fitting cylinder part 62 of the 1st rotary body 11, and the fitting recessed part 74 of the fitting cylinder part 72 of the 2nd rotary body 12 (or). By fitting), the relative rotation of the second rotating body 12 with respect to the first rotating body 11 is prevented. That is, the two first and second rotating bodies 11 and 12 are prevented from rotating.

  Note that the inner peripheral surface (inner diameter surface) of the fitting cylinder portion 62 of the first rotating body 11 and the outer peripheral surface (outer surface) of the fitting cylinder portion 72 of the second rotating body 12 excluding the plurality of fitting convex portions 64. A minute clearance is formed between the first rotating body 11 and the second rotating body 12 so as to allow relative rotation of the second rotating body 12. Further, a pinion gear portion 75 that is one of the components of the motion direction conversion mechanism is formed at the other end portion in the axial direction of the fitting cylindrical portion 72 of the second rotating body 12. The pinion gear portion 75 is a plurality of convex teeth formed in an arc shape on a part of the outer periphery (maximum outer diameter portion 79) of the fitting cylinder portion 72 of the second rotating body 12.

  The movement direction conversion mechanism includes a pinion gear portion 75 of the second rotating body 12 of the final gear and a plurality of rack teeth 13 that mesh with the pinion gear portion 75, and the rotational movement of the final gear is reciprocated in the direction of the central axis of the poppet valve 1. The rack and pinion part that converts to linear motion is constructed. The plurality of rack teeth 13 are provided on the side surface of the pinion opposite to the valve head side in the axial direction of the valve shaft portion 7 of the poppet valve 1 (the other side in the central axis direction of the valve shaft portion 7). ing. These rack teeth 13 are formed so as to repeat unevenness along the central axis direction of the valve shaft portion 7. In the present embodiment, the plurality of rack teeth 13 are formed integrally with the valve shaft portion 7 of the poppet valve 1, but after the plurality of rack teeth 13 are formed integrally with the rack bar, the poppet valve 1 is formed. The valve shaft 7 and the rack bar may be coupled so as to be able to operate integrally.

[Operation of Example 1]
Next, the operation of the secondary air supply system of the present embodiment, particularly the operation of the secondary air control valve incorporated in the secondary air supply system, that is, the secondary air when the secondary air control valve is driven to open. The flow will be described with reference to FIGS.

Here, a vehicle such as an automobile has three types of carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx), which are harmful components in exhaust gas discharged from the combustion chamber of the engine. Equipped with exhaust gas purification devices such as three-way catalytic converters that change elements into harmless components by chemical reaction, especially hydrocarbon (HC) to harmless water (H ₂ O) by oxidation action ing. However, the three-way catalyst must maintain the theoretical air-fuel ratio of 15: 1 because the chemical reaction cannot be performed correctly unless the mixing ratio of air and fuel at the time of engine combustion is the stoichiometric air-fuel ratio. In addition, the three-way catalyst does not operate well when the exhaust gas temperature is low (approximately 350 ° C. or less) immediately after the engine is started.

  Therefore, when the engine is started and the exhaust gas temperature is low, the electric air pump is operated to generate secondary air in the secondary air flow pipe, and the secondary air generated by the operation of the electric air pump is converted into the secondary air. It is desirable to guide the three-way catalytic converter through the flow path pipe, the secondary air control valve, and the engine exhaust pipe to promote the warm-up of the three-way catalyst and activate the three-way catalyst. Therefore, the ECU determines when the exhaust gas temperature is low, such as immediately after engine startup (when the exhaust gas temperature detected by the exhaust temperature sensor is lower than a predetermined value, or when the temperature of the three-way catalyst detected by the catalyst temperature sensor is predetermined). When the value is lower than the value, electric power (pump drive current) is supplied to the electric air pump to operate the electric air pump. Thereby, the pressure supply supply of the secondary air by the electric air pump is started.

  Further, the ECU supplies electric power (motor drive current) to the electric motor 4 of the secondary air control valve, and rotates the motor shaft 41 by a predetermined rotation angle necessary to drive the poppet valve 1 to open. Let As a result, the poppet valve 1 is driven to open by the motor torque via the power transmission mechanism including the gear reduction mechanism and the movement direction conversion mechanism (rack and pinion). Specifically, the motor shaft 41 of the electric motor 4 is rotated by a predetermined rotation angle, and the pinion gear 8 fixed to the motor shaft 41 of the electric motor 4 is rotated around the central axis of the motor shaft 41 by a predetermined rotation angle. The motor torque is transmitted to the large-diameter gear 47 of the intermediate reduction gear 9 that is rotated by an amount corresponding to the pinion gear 8.

As the large-diameter gear 47 rotates, the small-diameter gear of the intermediate reduction gear 9 rotates around the central axis of the intermediate reduction gear shaft 46 by a predetermined rotation angle, and the first gear of the final gear meshed with the small-diameter gear is rotated. The motor torque is transmitted to the final reduction gear portion 59 of the one rotating body 11. At this time, the torsion spring 10 generates (accumulates) a torsional elastic force in a direction to reversely rotate the final gear (the two first and second rotating bodies 11 and 12) to the original position.
The motor torque (rotational torque) of the electric motor 4 is changed from a plurality of fitting convex portions 64 provided on the inner peripheral surface of the fitting cylindrical portion 62 of the first rotating body 11 to these fitting convex portions 64. Is transmitted to the fitting cylinder portion 72 of the second rotating body 12 having a plurality of fitting recesses 74 that are engaged (or fitted) so as to be capable of transmitting power.

  That is, as the final reduction gear portion 59 of the first rotating body 11 rotates, the pinion gear portion 75 of the second rotating body 12 of the final gear rotates around the central axis of the final gear shaft 49 by a predetermined rotation angle, The valve shaft portion 7 having a plurality of rack teeth 13 meshing with the pinion gear portion 75 is one side in the central axis direction of the valve shaft portion 7 by the rotation angle of the pinion gear portion 75 (the valve head 6 of the poppet valve 1 is a flow path). It moves linearly to the side where the hole 5 is opened (the lower side in the figure). As a result, the back surface side of the valve head 6 provided on one end side (the lower end side in the figure) of the valve shaft portion 7 in the central axis direction is separated from the valve seat 2 to open the flow path hole 5. At this time, the valve head 6 of the poppet valve 1 is lifted downstream of the valve seat 2 in the flow direction of the secondary air, so that the valve head 6 is a check valve fluid while the poppet valve 1 is opened. The valve open state is maintained at a position immediately before the passage opening.

Therefore, the secondary air discharged from the discharge port of the electric air pump flows into the inlet pipe 14 from the inlet port 15 via the secondary air flow path pipe. The secondary air that has flowed into the inlet pipe 14 flows into the flow path hole 5 from the inlet port 15 via the fluid introduction flow path 16. Then, the secondary air that has passed through the flow path hole 5 passes between the outer peripheral edge of the valve head 6 of the poppet valve 1 and the flow path wall surface of the communication path 17 in the communication path 17, thereby making a check. It flows into the fluid passage of the valve. Then, the reed valve of the check valve is opened by the pressure of the secondary air flowing into the fluid passage port of the check valve, and the fluid passage port of the check valve is opened. As a result, the secondary air that has passed through the fluid passage port of the check valve flows out of the check valve housing and is sent to the three-way catalytic converter via the engine exhaust pipe on the upstream side of the three-way catalytic converter. . Therefore, even when the exhaust gas temperature is low when the engine is started, the secondary air generated by operating the electric air pump is guided to the three-way catalytic converter, so that oxygen (O ₂ ) burns and the three-way catalyst rises. Activate. In particular, the hydrocarbon (HC) is changed to harmless water (H ₂ O) by the oxidation action, so that the emission amount of the hydrocarbon (HC) into the atmosphere is reduced.

[Effect of Example 1]
As described above, in the secondary air control valve of this embodiment, the final gear of the power transmission mechanism (gear reduction mechanism) for driving the poppet valve 1 is the two first and second rotating bodies 11 having separate structures. , 12. The first rotating body 11 disposed on the motor side on the power transmission path of the power transmission mechanism (gear reduction mechanism) is formed of a resin material having a lower melting point and lower heat resistance than a metal material, The second rotating body 12 disposed on the valve side on the power transmission path of the power transmission mechanism (gear reduction mechanism) is made of a metal material that has better heat resistance than the resin material and has a high melting point.

  And the 1st rotary body 11 in the state which engaged the fitting convex part 64 of the fitting cylinder part 62 of the 1st rotary body 11, and the fitting recessed part 74 of the fitting cylinder part 72 of the 2nd rotary body 12. By inserting the fitting cylinder portion 72 of the second rotating body 12 into the fitting hole 61 of the fitting cylinder portion 62, the two first and second rotating bodies 11 and 12 are integrated to form the final gear. It is composed. At this time, the coupling end surface 63 of the fitting cylinder portion 62 of the first rotating body 11 and the coupling end surface 73 of the fitting cylinder portion 72 of the second rotating body 12 are in surface contact (or arranged to face each other with a minute gap). .

In the secondary air control valve incorporated in the secondary air supply system, the motor torque (driving force) generated in the electric motor 4 is transmitted to the poppet valve 1 to open the flow path hole 5 of the valve seat 2. When a failure (lock) occurs in the electric motor 4 or the power transmission mechanism (gear reduction mechanism), the poppet valve 1 is maintained in the open state.
When the poppet valve 1 fails to open due to the failure (lock) of the electric motor 4 or the power transmission mechanism (gear reduction mechanism), the communication passage 17 and the fluid introduction passage 16 formed inside the housing 3 The valve head 6 and the valve shaft 7 of the poppet valve 1 are exposed to the flowing high-temperature fluid (for example, high-temperature exhaust gas of 500 ° C. or higher), and the temperature of the poppet valve itself is increased to a high temperature. Then, the heat of the high-temperature exhaust gas is transmitted from the valve shaft portion 7 of the poppet valve 1 to the pinion gear portion 75 provided in the second rotating body 12 of the final gear, and the temperature of the second rotating body itself is raised to a high temperature. From the fitting concave portion 74 provided on the outer peripheral surface of the fitting cylindrical portion 72 of the second rotating body 12, it is transmitted to the fitting convex portion 64 provided on the inner peripheral surface of the fitting cylindrical portion 62 of the first rotating body 11. .

  Here, the first rotating body 11 on the motor side has lower rigidity or strength against heat than the material (metal material) of the second rotating body 12 on the valve side, and has a lower melting point than the material of the second rotating body 12. Since it is formed of a resin material, when the temperature of the fitting convex portion itself of the fitting cylindrical portion 62 of the first rotating body 11 is raised to a high temperature, the plurality of fitting convex portions 64 become the second rotating body. It is thermally deformed (melted) before the 12 fitting cylinders 72. The coupling force between the fitting cylinder portion 62 of the first rotating body 11 and the fitting cylinder portion 72 of the second rotating body 12 is weakened along with the thermal deformation of the fitting convex portions 64, and thus the first rotating body 11. The fitting cylinder part 62 and the fitting cylinder part 72 of the second rotating body 12 are disconnected from each other. Accordingly, the poppet valve 1 is returned to the valve fully closed position by the spring force (biasing force, spring load) of the torsion spring 10 and is closed (fully closed), and the flow path hole 5 of the valve seat 2 is closed.

  Therefore, it is possible to prevent the high-temperature exhaust gas from flowing into the communication passage 17 and the fluid introduction passage 16 formed inside the housing 3 when the poppet valve 1 of the secondary air control valve fails to open. The flow of high-temperature exhaust gas into the system inside the electric air pump from the valve seat 2 stops. That is, since the flow of high-temperature exhaust gas into the system on the electric air pump side with respect to the valve seat 2 can be reliably prevented, abnormal temperature rise in the secondary air supply system can be prevented. Thereby, a system failure can be prevented. Further, when a rubber material or the like is used as the material of the dust seal 33, it is possible to prevent the dust seal 33 from being thermally deteriorated due to the heat of the high-temperature exhaust gas, and thus it is possible to prevent a reduction in the sealing performance of the dust seal 33. .

  FIG. 5 shows a second embodiment of the present invention, and is a view showing a final gear of the gear reduction mechanism.

  In the secondary air control valve of the present embodiment, the final gear of the power transmission mechanism (gear reduction mechanism) that drives the poppet valve 1 is constituted by two first and second rotating bodies 11 and 12 having separate structures. ing. The first rotating body 11 disposed on the motor side on the power transmission path of the power transmission mechanism (gear reduction mechanism) is more rigid against heat than the material (metal material) of the second rotating body 12 on the valve side. The resin material is low in strength and has a lower melting point than the material of the second rotating body 12.

  Unlike the first embodiment, the first rotating body 11 of the present embodiment is not provided with the fitting cylinder portion 62, but a small diameter cylinder in which an axial hole 55 through which the final gear shaft 49 passes is formed. A portion 56 is provided. An annular coupling end surface (first coupling portion of the first rotating body 11) 63 is formed on the other axial end surface (end surface of the first rotating body 11) of the small diameter cylindrical portion 56. Further, unlike the first embodiment, the second rotating body 12 of the present embodiment is not provided with the fitting cylinder portion 72, but has a cylindrical shape in which an axial hole 71 through which the final gear shaft 49 passes is formed. The small-diameter cylindrical portion (cylindrical portion) 76 is provided. An annular coupling end surface (the second rotating body 12 of the second rotating body 12) disposed opposite to the coupling end surface 63 of the first rotating body 11 is disposed on one end surface (end surface of the second rotating body 12) of the small diameter cylindrical portion 76 in the axial direction. 2 coupling part) 73 is formed.

  A plurality of fitting convex portions 64 that are engaged with the coupling end surface 73 of the small diameter cylindrical portion 76 of the second rotating body 12 are integrally formed on the coupling end surface 63 of the small diameter cylindrical portion 56 of the first rotating body 11. Is formed. These fitting convex portions 64 are arranged at a predetermined interval (equal interval: for example, 120 ° interval) in the circumferential direction of the small-diameter cylindrical portion 56 and from the coupling end surface 63 of the small-diameter cylindrical portion 56 to the other side (second rotor side) ) Is provided in a streak shape so as to protrude toward the center. The plurality of fitting convex portions 64 are orthogonal to the axial direction of the small diameter cylindrical portion 56 of the first rotating body 11 from the opening end of the axial hole 55 toward the outer periphery (outer diameter surface) of the small diameter cylindrical portion 56. It extends in the radial direction.

In addition, a plurality of fitting recesses 74 that engage the plurality of fitting protrusions 64 are integrally formed on the coupling end surface 73 of the small diameter cylindrical portion 76 of the second rotating body 12. These fitting concave portions 74 are provided in a streak shape at positions corresponding to the fitting convex portions 64 on the coupling end surface 73 of the small diameter cylindrical portion 76. And the fitting convex part 64 of the small diameter cylindrical part 56 of the 1st rotary body 11 and the fitting concave part 74 of the small diameter cylindrical part 76 of the 2nd rotary body 12 are engaged, and the small diameter cylindrical part of the 1st rotary body 11 is engaged. 56 coupling end surfaces 63 and the coupling end surface 73 of the small-diameter cylindrical portion 76 of the second rotating body 12 are coupled (or joined), whereby the two first and second rotating bodies 11 and 12 are integrated to form the final gear. Is configured.
In the present embodiment, the same effect as that of the first embodiment can be achieved.

  FIG. 6 shows a third embodiment of the present invention, and is a view showing a final gear of the gear reduction mechanism.

  In the secondary air control valve of the present embodiment, the final gear of the power transmission mechanism (gear reduction mechanism) that drives the poppet valve 1 is constituted by two first and second rotating bodies 11 and 12 having separate structures. ing. The first rotating body 11 disposed on the motor side on the power transmission path of the power transmission mechanism (gear reduction mechanism) is more rigid against heat than the material (metal material) of the second rotating body 12 on the valve side. The resin material is low in strength and has a lower melting point than the material of the second rotating body 12. And the 1st rotary body 11 of a present Example is different from Example 1, and the fitting convex part 64 is not provided in the internal peripheral surface of the fitting cylinder part 62. FIG. Further, unlike the first embodiment, the second rotating body 12 is not provided with the fitting recess 74 on the outer peripheral surface of the fitting cylinder portion 72.

  Then, when the final gear is manufactured, the fitting cylinder portion 72 of the second rotator 12 is insert-molded inside the fitting cylinder portion 62 of the first rotator 11 to thereby form two first and second two. The rotating bodies 11 and 12 are integrated. Further, between the inner peripheral surface of the fitting cylinder portion 62 of the first rotating body 11 and the outer peripheral surface of the fitting cylinder portion 72 of the second rotating body 12, the first rotating body 11, the second rotating body 12, and the like. The boundary surface is formed. In the present embodiment, the inner peripheral surface of the fitting cylindrical portion 62 of the first rotating body 11 and the outer peripheral surface of the fitting cylindrical portion 72 of the second rotating body 12 are simple cylindrical surfaces. Further, the first rotating body 11 and the second rotating body 12 are disposed between the connecting end face 63 of the fitting cylinder portion 62 of the first rotating body 11 and the connecting end face 73 of the fitting cylinder portion 72 of the second rotating body 12. The boundary surface is formed. In the present embodiment, the coupling end surface 63 of the fitting cylinder portion 62 of the first rotating body 11 and the coupling end surface 73 of the fitting cylinder portion 72 of the second rotating body 12 are flat.

Here, in the secondary air control valve incorporated in the secondary air supply system, the motor torque (driving force) generated in the electric motor 4 is transmitted to the poppet valve 1 to open the flow path hole 5 of the valve seat 2. When a failure (lock) occurs in the electric motor 4 or the power transmission mechanism (gear reduction mechanism) during the operation, the poppet valve 1 is maintained in the open state.
When the poppet valve 1 fails to open due to the failure (lock) of the electric motor 4 or the power transmission mechanism (gear reduction mechanism), the communication passage 17 and the fluid introduction passage 16 formed inside the housing 3 The valve head 6 and the valve shaft 7 of the poppet valve 1 are exposed to the flowing high-temperature fluid (for example, high-temperature exhaust gas of 500 ° C. or higher), and the temperature of the poppet valve itself is increased to a high temperature. Then, the heat of the high-temperature exhaust gas is transmitted from the valve shaft portion 7 of the poppet valve 1 to the pinion gear portion 75 provided in the second rotating body 12 of the final gear, and the temperature of the second rotating body itself is raised to a high temperature. Then, it is transmitted from the fitting cylinder part 72 of the second rotating body 12 to the fitting cylinder part 62 of the first rotating body 11.

  Here, in the final gear of this embodiment, the fitting cylinder portion 72 of the second rotating body 12 is insert-molded inside the fitting cylinder portion 62 of the first rotating body 11, and the first rotating body 11 is The second rotating body 12 is made of a resin material having a lower rigidity or strength against heat than the material (metal material) of the second rotating body 12 and a lower melting point than the material of the second rotating body 12. When the temperature of the fitting cylinder part itself is raised to a high temperature, the inner peripheral surface and the coupling end face 63 of the fitting cylinder part 62 are thermally deformed (melted down) before the fitting cylinder part 72 of the second rotating body 12. ) With the thermal deformation of the fitting cylinder portion 62 of the first rotating body 11, the fitting cylinder portion 62 of the first rotating body 11 peels from the fitting cylinder portion 72 of the second rotating body 12.

  That is, the first rotation with the boundary surface between the two first and second rotating bodies 11 and 12 as a boundary by the heat of the hot exhaust gas flowing into the communication passage 17 and the fluid introduction passage 16 formed inside the housing 3. The fitting cylinder part 62 of the body 11 peels from the fitting cylinder part 72 of the second rotating body 12. As a result, since the coupling force between the fitting cylinder portion 62 of the first rotating body 11 and the fitting cylinder portion 72 of the second rotating body 12 is weakened, the fitting cylinder portion 62 of the first rotating body 11 and the second rotating body are reduced. The connection with the 12 fitting cylinders 72 is released. Accordingly, the poppet valve 1 is returned to the valve fully closed position by the spring force (biasing force, spring load) of the torsion spring 10 and is closed (fully closed), and the flow path hole 5 of the valve seat 2 is closed.

  Therefore, it is possible to prevent the high-temperature exhaust gas from flowing into the communication passage 17 and the fluid introduction passage 16 formed inside the housing 3 when the poppet valve 1 of the secondary air control valve fails to open. The flow of high-temperature exhaust gas into the system inside the electric air pump from the valve seat 2 stops. That is, since the flow of high-temperature exhaust gas into the system on the electric air pump side with respect to the valve seat 2 can be reliably prevented, abnormal temperature rise in the secondary air supply system can be prevented. Thereby, a system failure can be prevented.

[Modification]
In this embodiment, the present invention is applied to a power transmission mechanism (especially a gear reduction mechanism) of a valve drive device (motor actuator) that drives an ASV poppet valve 1 incorporated in a secondary air supply system mounted on a vehicle such as an automobile. However, the present invention is not limited to this. For example, an intake air flow control valve (such as a swirl flow control valve or a valve that exposes a valve body to combustion heat flowing backward from the combustion chamber of the internal combustion engine into the intake passage) A tumble flow control valve, etc.), an intake air amount control valve (throttle valve, idle speed control valve, etc.), or an exhaust gas recirculation passage for recirculating exhaust gas flowing out from the combustion chamber of the internal combustion engine to the intake passage of the internal combustion engine A valve drive device (actuator) for driving a valve body (valve) of an air control valve such as an exhaust gas recirculation amount control valve (EGR control valve) for controlling the amount of EGR gas passing therethrough It may be applied to a power transmission mechanism). In these cases, the check valve need not be provided.

  Further, the present invention provides power transmission of a valve drive device (actuator) for driving a valve body (valve) of an air control valve such as an air flow path opening / closing valve, an air flow path cutoff valve, an air flow rate control valve, an air pressure control valve. You may apply to mechanisms (a torque transmission mechanism, a gear reduction mechanism, etc.). Moreover, a rotary valve, a butterfly valve, a shutter valve, a ball valve, or the like may be used as the valve, and the valve head and the valve shaft are manufactured separately, and can be operated integrally thereafter. A valve in which the valve head and the valve shaft are combined may be used. As the fluid, gas such as air (secondary air, air) or evaporated fuel can be used.

  In this embodiment, the electric motor 4 that generates motor torque (driving force, rotational torque) when power is supplied as a power source is used. However, a rotary solenoid may be used instead of the electric motor 4 as a power source. good. Further, as a rotating body, not only a gear but also a lever part such as a link lever may be used. In this embodiment, an example in which the torsion (coil) spring 10 is used as the spring has been described. However, a double coil spring, an unequal pitch coil spring, a saddle pitch coil spring, a leaf spring, or the like may be used as the spring.

  In this embodiment, the two first and second rotating bodies incorporated in the power transmission mechanism (torque transmission mechanism, gear reduction mechanism, etc.) of the present invention are used as the two first first components constituting the final gear of the gear reduction mechanism. Although applied to the second rotating bodies 11 and 12, the intermediate reduction gear 9 of the gear reduction mechanism may be changed to a separate structure. In this case, the first rotating body on the power source (motor) side constitutes the large diameter gear 47, and the second rotating body on the valve body (valve) side constitutes the small diameter gear. The final gear is integrated with a metal material or the like, and the large-diameter gear 47 is formed of a material having a lower melting point than that of the small-diameter gear.

  In this embodiment, the poppet valve 1 is pressed against the valve seat 2 against the second rotating body 12 constituting the output gear of the power transmission mechanism (torque transmission mechanism, gear reduction mechanism, etc.), that is, the flow path hole. (Air flow path) 5 A torsion (coil) spring 10 is used as a spring load applying means for applying a spring load (spring force, biasing force) in a direction to return the valve to the fully closed position. You may use the load provision means which applies a load with respect to a body (valve) in the direction which presses a valve to a valve seat, ie, the direction which returns to the valve fully closed position which fully closes an air flow path.

  In this embodiment, the final gear (two first and second rotating bodies 11, 12) of the power transmission mechanism (torque transmission mechanism, gear reduction mechanism, etc.) is fixed to the housing 3 (support shaft, Although fixed relative to the fixed shaft 49, the final gear (two first and second rotating bodies 11, 12) of the power transmission mechanism (torque transmission mechanism, gear reduction mechanism, etc.) is provided. The final gear shaft (output shaft, fixed shaft) rotatably supported by the housing 3 may be integrally rotated. In this case, the final gear shaft is formed as a separate structure and fixed to the axial holes of the two first and second rotating bodies 11 and 12.

  Further, at least the fitting cylinder part (first coupling part) 62 or the coupling end face 63 or the fitting convex part 64 of the first rotating body 11 and at least the fitting cylinder part (second coupling part) 72 of the second rotating body 12. You may form with the material whose melting | fusing point is lower than this material. Moreover, you may form the housing 3 with the material whose melting | fusing point is lower than the material of a 2nd rotary body (12).

It is sectional drawing which showed the whole structure of the secondary air control valve (Example 1). FIG. 1 is a plan view showing an overall structure of a motor actuator (Example 1). (Example 1) which is the perspective view which showed the main structures of the secondary air control valve. (Example 1) which is the exploded view which showed the last gear of the gear reduction mechanism. (Example 2) which is the exploded view which showed the last gear of the gear reduction mechanism. (Example 3) which is sectional drawing which showed the last gear of the gear reduction mechanism. It is the perspective view which showed the valve drive device (prior art).

Explanation of symbols

1 Poppet valve 2 Valve seat (valve seat, peripheral edge of valve opening)
3 Housing 4 Electric motor (power source)
8 Pinion gear 9 Intermediate reduction gear 10 Torsion spring (return spring, coil spring)
11 First Rotating Body 12 Second Rotating Body 13 Rack Teeth 49 Final Gear Shaft of Final Gear (Power Transmission Mechanism Shaft)
50 Cylindrical coil portion of torsion spring 51 First coil end of torsion spring 52 Second coil end of torsion spring 56 Small diameter cylindrical portion (first coupling portion) of first rotating body
62 Fitting cylinder part (first coupling part) of first rotating body
63 Coupling end surface of first rotating body 64 Fitting convex portion of first rotating body 72 Fitting cylinder portion of second rotating body (second coupling portion)
73 Coupling end surface of the second rotating body 74 Fitting convex portion of the second rotating body 76 Small diameter cylindrical portion (second coupling portion) of the second rotating body

Claims (9)

(A) a housing forming an air flow path communicating with the combustion chamber of the internal combustion engine;
(B) a valve for opening and closing the air flow path;
(C) a power source that generates a driving force for driving the valve, and a power transmission mechanism that transmits the driving force of the power source to the valve, and a valve driving device that drives the valve in the valve opening operation direction; ,
(D) In an air control valve provided with a spring for urging the valve in the valve closing operation direction,
The power transmission mechanism has two first and second rotating bodies that are arranged on the same axis and rotate integrally within the operating range of the valve,
The first rotating body is disposed on the power source side of the second rotating body on the power transmission path of the power transmission mechanism, and has a first coupling portion on the second rotating body side,
The second rotating body is disposed on the valve side of the first rotating body on the power transmission path of the power transmission mechanism, and is coupled to the first coupling portion directly on the first rotating body side. Having a joint,
The air control valve according to claim 1, wherein the first coupling portion is formed of a material having a melting point lower than that of the second coupling portion. The air control valve according to claim 1,
The air control valve according to claim 1, wherein at least the first coupling portion of the first rotating body is formed of a material having lower rigidity or strength against heat than a material of the second coupling portion. In the air control valve according to claim 1 or 2,
The air control valve according to claim 1, wherein at least the first coupling portion of the first rotating body is made of a material having a melting point lower than that of the second rotating body. In the air control valve according to any one of claims 1 to 3,
In the first rotating body, at least the first coupling portion is formed of a resin material, and in the second rotating body, at least the second coupling portion is formed of a metal material. Air control valve. In the air control valve according to any one of claims 1 to 4,
The housing has a valve seat that regulates a fully closed position of the valve;
The air control valve, wherein the spring applies a load to the second rotating body or the valve in a direction in which the valve is pressed against the valve seat. In the air control valve according to any one of claims 1 to 5,
The power transmission mechanism has an axis extending in the axial direction,
2. The air control valve according to claim 1, wherein the spring includes a coil portion disposed so as to spirally surround the shaft, and two coil terminals drawn from both ends of the coil portion. In the air control valve according to any one of claims 1 to 6,
The power transmission mechanism has one shaft extending in the axial direction,
The air control valve characterized in that the two first and second rotating bodies are arranged so as to surround the periphery of the shaft. In the air control valve according to any one of claims 1 to 7,
The second coupling portion has a recess provided on the surface or end surface of the second rotating body,
The air coupling valve, wherein the first coupling portion has a convex portion that engages with the concave portion. In the air control valve according to any one of claims 1 to 7,
The second coupling part is insert-molded inside the first coupling part,
An air control valve characterized in that a boundary surface between the two first and second rotating bodies is formed between the first coupling portion and the second coupling portion.

Images