JP4600319B2 - Method for manufacturing fluid control valve - Google Patents

Description

  The present invention relates to a manufacturing method of a fluid control valve in which a valve for controlling fluid is welded and fixed inside a housing with an inclination with respect to a central axis of a shaft. The present invention relates to a manufacturing method of a fluid control valve that is fixedly welded while being inclined with respect to a central axis of a shaft.

[Conventional technology]
Conventionally, as an example of a fluid control valve, a part of exhaust gas (EGR) is used for the purpose of reducing harmful substances (for example, nitrogen oxides: NOx, etc.) contained in exhaust gas flowing out from the combustion chamber of an internal combustion engine. 2. Description of the Related Art There is known an exhaust gas recirculation amount control valve incorporated in the middle of an exhaust gas recirculation pipe of an exhaust gas recirculation device that recirculates a high-temperature fluid such as gas) to an intake system of an internal combustion engine. As an example of this exhaust gas recirculation amount control valve, the driving force of the electric motor is transmitted to the shaft via a gear reduction mechanism, and a butterfly valve supported and fixed at one end portion in the axial direction of the shaft is driven. An electric EGR control valve that rotates in an operating range from a fully closed position to a valve fully open position is known (see, for example, Patent Document 1).

  Here, in the EGR control valve that controls the flow rate (EGR amount) of a high-temperature fluid such as EGR gas, as shown in FIG. 4, a housing (not shown) that forms part of the exhaust gas recirculation pipe, A tubular liner (nozzle) 101 fitted and held in the housing, a butterfly valve 102 accommodated in the liner 101 so as to be freely opened and closed, and a shaft 103 that supports and fixes the butterfly valve 102 are configured. In the EGR control valve, an annular seal ring groove 104 is formed on the entire outer peripheral end surface of the butterfly valve 102, and a seal ring 105 is attached to the seal ring groove 104.

  A valve mounting portion 106 for fixing the butterfly valve 102 by welding using welding means is provided on one end side of the shaft 103 in the axial direction. The butterfly valve 102 is held and fixed to the valve mounting portion 106 in a state where it is inclined by a predetermined inclination angle with respect to the axial direction of the shaft 103. For this reason, the through hole 107 into which the valve mounting portion 106 is fitted penetrates the butterfly valve 102 while being inclined with respect to the axis of the butterfly valve 102 in the plate thickness direction. In the EGR control valve, a welded portion 109 is formed by laser welding the outer peripheral surface of the valve mounting portion 106 of the shaft 103 and the hole wall surface of the through hole 107 of the butterfly valve 102 using a laser welding apparatus.

[Conventional technical problems]
However, in the EGR control valve described in Patent Document 1, the laser beam output from the laser welding apparatus from one side in the axial direction of the exhaust gas recirculation path 110 formed in the liner 101 is transmitted to the butterfly valve 102 and the shaft 103. However, since the cross-sectional shape of the shaft 103 is circular, even if the laser beam is scanned along the outer shape of the bulb mounting portion 106, a portion where laser welding cannot be performed occurs. 109 is formed in a substantially U shape (or a semicircular elliptical arc shape).

  Thus, even when the butterfly valve 102 is closed at the fully closed position and the seal ring sliding surface of the seal ring 105 is brought into close contact with the inner peripheral surface (seal surface) of the liner 101, the valve of the shaft 103 A high-temperature fluid such as EGR gas passes between the outer peripheral surface of the mounting portion 106 and the hole wall surface of the through-hole 107 of the butterfly valve 102, that is, through the portion where the butterfly valve 102 and the shaft 103 cannot be laser-welded. There is a problem that the amount of high-temperature fluid leakage increases when the butterfly valve 102 is fully closed.

  Further, the laser welding apparatus irradiates a portion A (one end portion of the welded portion 109) at the joint portion between the butterfly valve 102 and the shaft 103 with a laser beam, and then irradiates the laser beam with the outer peripheral surface of the shaft mounting portion 106 Is moved to a substantially U shape (or a semi-circular elliptical arc shape), and laser welding is performed until it reaches part B (the other end of the welded part 109) at the joint between the butterfly valve 102 and the shaft 103. ing. In addition, a necessary minimum gap is provided between the outer peripheral surface of the valve mounting portion 106 and the hole wall surface of the through hole 107 so as to insert the valve mounting portion 106 into the through hole 107 (for example, gap fitting). ing.

  As a result, the butterfly valve 102 is pulled toward the portion A where laser welding is started, and the position of the butterfly valve 102 deviates from the normal position. That is, the positional accuracy of the butterfly valve 102 with respect to the shaft mounting portion 106 of the shaft 103 is deteriorated. As a result, the gap between the portions where the butterfly valve 102 and the shaft 103 cannot be laser-welded increases, and there is a problem that the amount of high-temperature fluid leakage when the butterfly valve 102 is fully closed increases.

  Note that when the valve mounting portion 106 and the through hole 107 are tightly fitted (press-fit), the butterfly valve 102 may be distorted and the roundness of the butterfly valve 102 may deteriorate. Here, since the seal ring 105 is a C-shaped metal ring, the deterioration of the roundness of the butterfly valve 102 cannot be compensated, and the seal ring 105 is mounted in the seal ring groove 104 in a tilted state. There is a possibility that the sealing performance of the seal ring 105 is deteriorated when the butterfly valve 102 is fully closed. Thus, it is not desirable to employ an interference fit.

Further, in the EGR control valve described in Patent Document 1, since the butterfly valve 102 is thin, the butterfly valve 102 is deformed by the welding heat when laser welding is performed using a laser welding apparatus. Roundness may deteriorate. Also in this case, since the deterioration of the roundness of the butterfly valve 102 cannot be compensated for by the seal ring 105, there is a possibility that the seal ring 105 is mounted in the seal ring groove 104 in an inclined state. There arises a problem that the sealing performance of the seal ring 105 at the time of closing deteriorates.
JP 2005-233063 A (page 1-15, FIGS. 1-6)

  An object of the present invention is to provide a fluid control valve manufacturing method capable of preventing fluid leakage when the valve is fully closed. Another object of the present invention is to provide a method of manufacturing a fluid control valve that can improve the positional accuracy of the valve with respect to the shaft.

According to the first aspect of the present invention, the shaft is fitted to the swash plate-like valve that is held and fixed to the shaft using welding means in a state inclined with respect to the central axis of the shaft inside the housing. A fitting groove to be fitted is provided. And the fitting groove of the valve is opened only at one end surface in the plate thickness direction of the valve. Accordingly, in the welding process in which the groove wall surface of the valve fitting groove and the shaft are welded using welding means to form a welded portion between the valve and the shaft, the shaft and the fitting groove of the valve are temporarily fitted. Even if there is a portion that cannot be welded, a through hole that penetrates through both end faces of the valve in the plate thickness direction is not formed. Therefore, when the valve is fully closed, fluid does not leak through the part of the fitting portion between the shaft and valve fitting groove that cannot be welded, and fluid leakage is reliably prevented when the valve is fully closed. can do.
Further, a disc-shaped butterfly valve extending from the center to the outer diameter side in the radial direction may be employed as the valve. In the vicinity of the center located on the inner diameter side in the radial direction with respect to the outer peripheral edge of the butterfly valve, a thick portion having a thickness greater than that of the outer peripheral edge is provided. And within the range where the butterfly valve plate is thick, the groove wall surface of the fitting groove of the butterfly valve and the shaft (the shaft outer diameter surface) are welded to form a welded portion between the butterfly valve and the shaft. Further, it is possible to prevent the roundness of the outer peripheral edge portion of the butterfly valve from being lowered due to deformation of the thin outer peripheral edge portion of the butterfly valve by welding heat. Therefore, the annular clearance between the outer peripheral end face of the butterfly valve and the flow passage wall surface (inner peripheral face) of the housing when the butterfly valve is fully closed becomes an appropriate value (or zero), and the amount of fluid leakage when the butterfly valve is fully closed Can be reduced.

According to the second aspect of the present invention, the welded portion in which the groove wall surface of the fitting groove of the valve and the shaft are welded using welding means is used in the direction of the central axis of the shaft or the groove length direction of the fitting groove of the valve. The welding process which forms in a straight line along is provided.
In this case, the weld length of the welded portion can be made longer in the same direction as the central axis direction of the shaft or the groove length direction of the fitting groove of the valve, so that the effective weld length between the valve and the shaft is sufficiently secured. can do. Further, when a laser welding apparatus is used as the welding means, it is only necessary to scan the laser beam in a straight line, and the laser beam is substantially U-shaped (or a semicircular elliptical arc shape) as in the prior art. Since it is not necessary to perform scanning, the welding operation between the valve and the shaft is facilitated, and the productivity of the fluid control valve can be improved.

According to the third aspect of the present invention, the welded portion in which the groove wall surface of the fitting groove of the valve and the shaft are welded using welding means is perpendicular to the axial direction of the fluid flow path formed in the housing. A welding process for forming on a vertical line.
In this case, the weld length of the welded portion can be made longer in the direction perpendicular to the axial direction of the fluid flow path formed in the housing, so that the effective weld length between the valve and the shaft must be sufficiently secured. Can do. Further, when a laser welding apparatus is used as the welding means, it is only necessary to scan the laser beam in a straight line, and the laser beam is substantially U-shaped (or a semicircular elliptical arc shape) as in the prior art. Since it is not necessary to perform scanning, the welding operation between the valve and the shaft is facilitated, and the productivity of the fluid control valve can be improved.

According to invention of Claim 4, the weld part which welded the groove | channel wall surface of the fitting groove of a valve | bulb, and the shaft (the shaft outer diameter surface) using a welding means is formed in parallel and linearly. Two rows of parallel welds are used.
According to the fifth aspect of the present invention, the both sides in the width direction of the shaft (the outer diameter surface of the shaft) and the groove wall surfaces on both sides in the groove width direction of the fitting groove of the valve are welded simultaneously using the welding means. A welding process is provided in which two rows of parallel welds are formed at the welded portion of the valve and the shaft.
In this case, during the welding process, the fitting groove of the valve is not pulled to either one of both sides in the groove width direction, and the position of the valve is not deviated from the normal position. That is, the positional accuracy of the valve with respect to the shaft can be improved. Moreover, since two rows of welded portions can be formed simultaneously, the welding work time between the valve and the shaft can be shortened, and the productivity of the fluid control valve can be improved.

According to the sixth aspect of the present invention, the shaft is fitted to the swash plate-like valve that is held and fixed to the shaft using welding means in a state inclined with respect to the central axis of the shaft inside the housing. A fitting groove to be fitted is provided. And the fitting groove of the valve is opened only at one end surface in the plate thickness direction of the valve. That is, there is no through-hole formed so as to communicate with both end faces in the plate thickness direction of the valve. Therefore, when the valve is fully closed, fluid does not leak from the gap between the groove wall surface of the fitting groove of the valve and the shaft, and fluid leakage when the valve is fully closed can be reliably prevented.
Further, a disc-shaped butterfly valve extending from the center to the outer diameter side in the radial direction may be employed as the valve. In the vicinity of the center located on the inner diameter side in the radial direction with respect to the outer peripheral edge of the butterfly valve, a thick portion having a thickness greater than that of the outer peripheral edge is provided. As a result, it is possible to prevent the outer peripheral edge of the butterfly valve having a thin plate thickness from being deformed by welding heat or the like and reducing the roundness of the outer peripheral edge of the butterfly valve. Therefore, the annular clearance between the outer peripheral end face of the butterfly valve and the flow passage wall surface (inner peripheral face) of the housing when the butterfly valve is fully closed becomes an appropriate value (or zero), and the amount of fluid leakage when the butterfly valve is fully closed Can be reduced.

According to invention of Claim 7 , the cross-sectional shape of the shaft is made into circular shape (or hollow cylindrical shape). Then, the groove depth or groove width of the fitting groove of the valve may be about the dimension in the radial direction of the shaft. The fitting state of the valve fitting groove and the shaft may be a gap fitting that allows the valve to move with respect to the shaft, or may be a light press fitting .

According to the eighth aspect of the present invention, the seal ring is provided for sealing the gap between the flow path wall surface of the housing and the outer peripheral end surface of the butterfly valve when the butterfly valve is fully closed. An annular groove for mounting the seal ring is provided on the entire outer peripheral end face of the butterfly valve. Therefore, fluid leakage when the butterfly valve is fully closed can be prevented by fitting the seal ring into the annular groove of the butterfly valve.

The best mode for carrying out the present invention is to provide a butterfly valve, which is a disc-shaped swash plate , for the purpose of preventing fluid leakage when the valve is fully closed, using only one end face in the plate thickness direction of the butterfly valve. This was realized by fitting the shaft into the opening fitting groove. Further, the object of improving the positional accuracy of the butterfly valve to the shaft, the welding means and both sides in the width direction on both sides of the groove wall surface and the shaft of the groove width direction of the fitting groove of the butterfly valve (shaft outer diameter surface of) This was realized by simultaneously welding and forming two rows of parallel welds.

[Configuration of Example 1]
1 to 3 show Embodiment 1 of the present invention, and FIG. 1 is a view showing an exhaust gas recirculation amount control valve.

  The exhaust gas recirculation device of this embodiment is used for an internal combustion engine (hereinafter referred to as an engine) mounted on a vehicle such as an automobile, for example, and is an exhaust gas flowing out from a combustion chamber for each cylinder of the engine. This is an EGR device that recirculates a high-temperature fluid such as EGR gas (exhaust gas recirculation gas) that is a part to the intake system of the engine. Here, a direct injection diesel engine in which fuel is directly injected into the combustion chamber is employed as the engine. The engine includes an engine intake pipe for supplying intake air into the combustion chamber for each cylinder, and an engine for exhausting exhaust gas flowing out from the combustion chamber for each cylinder to the outside via the exhaust purification device. It has an exhaust pipe.

  The exhaust gas recirculation device is disposed in the middle of the exhaust gas recirculation pipe (not shown) for introducing EGR gas from the engine exhaust pipe to the engine intake pipe, and is disposed in the engine intake pipe. An exhaust gas recirculation amount control valve (hereinafter referred to as an EGR control valve) that variably controls the recirculation amount (EGR amount) of the recirculated EGR gas is provided. In this embodiment, the upstream end of the exhaust gas recirculation pipe in the EGR gas flow (air flow) direction is hermetically connected to an engine exhaust pipe (for example, an exhaust manifold), and the EGR of the exhaust gas recirculation pipe A downstream end in the gas flow (air flow) direction is hermetically connected to an engine intake pipe (for example, an intake manifold).

  The EGR control valve of the present embodiment corresponds to the fluid control valve of the present invention, and an EGR amount that mixes EGR gas, which is part of exhaust gas flowing out from the combustion chamber of each cylinder of the engine, into the intake air. This is a fluid flow control valve that variably controls (the EGR rate relative to the new intake air amount). This EGR control valve is a butterfly valve (EGR control valve) that changes the opening area of a housing 1 that forms part of an exhaust gas recirculation pipe and an exhaust gas recirculation path (fluid flow path) 2 that is formed inside the housing 1. 4) and a coil spring (valve urging means) 8 for urging the butterfly valve 4 in the valve closing direction or the valve opening direction. Here, in the housing 1 of this embodiment, a tubular liner (nozzle) 3 having an exhaust gas recirculation path 2 formed therein is fitted and held.

  The butterfly valve 4 of the present embodiment is inclined by a predetermined inclination angle with respect to the central axis of the valve shaft 5 that rotates by receiving the driving force of an actuator such as an electric motor 9 or a power transmission mechanism. This is a swash plate-like valve that is held and fixed to one end side in the central axis direction of the valve shaft 5 by using the laser welding apparatus 10. The butterfly valve 4 is formed in a substantially disk shape from a heat-resistant material resistant to high temperatures, such as stainless steel, and controls a butterfly rotary valve that controls the EGR amount of EGR gas mixed into the intake air flowing in the engine intake pipe. It is.

  The butterfly valve 4 is rotated in the operating range from the fully closed position of the valve to the fully open position of the valve based on a control signal from an engine control unit (hereinafter referred to as ECU) during engine operation. This is a valve body that variably controls the EGR amount by changing the opening area (exhaust gas flow area) of the reflux path 2. Here, the valve fully closed position refers to the space between the flow passage wall surface of the housing 1 (inner peripheral surface of the nozzle 3) and the end surface of the outer edge in the radial direction of the butterfly valve 4 (outer peripheral end surface of the butterfly valve 4). Is the valve opening (θ = 0 °) at which the EGR amount of the EGR gas flowing through the exhaust gas recirculation passage 2 is minimized. The valve fully open position is a valve opening (θ = 70 to 90 °) at which the EGR amount of the EGR gas flowing inside the exhaust gas recirculation path 2 is maximized.

  An annular seal ring groove (annular groove) 6 is continuously formed in the circumferential direction on the outer peripheral end face of the butterfly valve 4. That is, the seal ring groove 6 is provided around the entire outer peripheral end surface (the entire circumference) of the butterfly valve 4. One seal ring 7 is fitted into the seal ring groove 6. That is, the seal ring 7 is sealed so that the inner diameter side end can move in the seal ring groove 6 in the radial direction, the axial direction, and the circumferential direction with the outer diameter side end protruding from the outer peripheral end surface of the butterfly valve 4. It is fitted and held in the ring groove 6.

  Therefore, the EGR control valve of the present embodiment is used when the butterfly valve 4 is stopped at the fully closed position, that is, with respect to the axial direction of the average flow of the EGR gas flowing in the exhaust gas recirculation path 2. When the butterfly valve 4 is set in a substantially perpendicular direction (vertical) (when the butterfly valve 4 is fully closed), it is orthogonal to the axial direction of the seal ring 7 fitted in the seal ring groove 6 of the butterfly valve 4. The gap between the inner peripheral surface of the nozzle 3 and the outer peripheral end surface of the butterfly valve 4 is configured to be hermetically sealed (sealed) using a radial (expansion direction) tension. Details of the butterfly valve 4 and the valve shaft 5 will be described later.

  Here, the valve driving device (motor actuator) for opening or closing the butterfly valve 4 according to this embodiment includes an electric motor 9 that generates a driving force upon receiving electric power, and a motor shaft of the electric motor 9. 21 is constituted by a power transmission mechanism (in this example, a gear reduction mechanism) for transmitting the rotational motion of 21 to the valve shaft 5. The electric motor 9 is a direct current (DC) motor such as a brushless DC motor or a brushed DC motor. An alternating current (AC) motor such as a three-phase induction motor may be used.

  The gear reduction mechanism reduces the rotational speed of the motor shaft 21 of the electric motor 9 to a predetermined reduction ratio, and transmits the motor output shaft torque (driving force) of the electric motor 9 to the valve shaft 5. A power transmission mechanism is configured. The gear reduction mechanism is engaged with a pinion gear (motor gear) 22 fixed to the outer periphery of the motor shaft 21 of the electric motor 9, an intermediate reduction gear 23 that rotates in mesh with the motor gear 22, and rotates in mesh with the intermediate reduction gear 23. And a valve gear 24.

  The motor gear 22 is disposed so as to surround the outer periphery of the motor shaft 21 of the electric motor 9 in the circumferential direction, and has a cylindrical portion that is fitted and fixed to the outer periphery of the motor shaft 21. The intermediate reduction gear 23 is disposed so as to surround the outer periphery of an intermediate shaft (intermediate shaft) 25 disposed in parallel with the motor shaft 21 and the valve shaft 5 of the electric motor 9. It has a cylindrical portion that fits rotatably on the outer periphery of 25. The valve gear 24 is formed of a resin material, and a valve gear plate 26 is insert-molded on the inner peripheral portion.

  Here, the valve drive device, in particular, the electric motor 9 is configured to be energized and controlled by the ECU. The ECU includes a CPU for performing control processing and arithmetic processing, a storage device (memory such as ROM and RAM) for storing a control program or control logic and various data, an input circuit (input unit), and an output circuit (output unit). A microcomputer having a well-known structure configured to include the above functions is provided. Further, when an ignition switch (not shown) is turned on (IG / ON), the ECU turns the exhaust gas recirculation amount (EGR amount), that is, the rotation angle (valve opening degree) of the butterfly valve 4 based on the control program stored in the memory. ) Is electronically controlled.

  The microcomputer is connected to a crank angle sensor, an accelerator opening sensor, an air flow meter, a cooling water temperature sensor, and the like. The sensor signals from these various sensors are A / D converted by an A / D converter and then input to a microcomputer. Further, the microcomputer converts the rotation angle (valve opening) of the butterfly valve 4 into an electric signal, and how much EGR gas is mixed into the intake air flowing through the engine intake pipe to the ECU, that is, into the engine intake pipe. An EGR amount sensor for outputting the EGR amount of the EGR gas is connected.

The EGR amount sensor is a non-contact rotation angle detection device that detects the rotation angle (valve opening) of the butterfly valve 4, and is a split permanent magnet (magnet) 27 fixed to the inner peripheral side of the valve gear 24. A split type yoke (not shown) magnetized by the magnet 27, a Hall IC 29 arranged on the sensor cover 28 side, and the like.
The Hall IC 29 is disposed so as to face the magnet 27 and the yoke, and the Hall IC 29 outputs a voltage signal corresponding to the magnetic flux density linked to itself. Note that a Hall element or a magnetoresistive element may be used instead of the Hall IC 29 as the non-contact type magnetic detection element.

  The housing 1 of this embodiment is formed into a predetermined shape by die casting of an aluminum alloy, and the butterfly valve 4 can be rotated in the rotation direction from the valve fully closed position to the valve fully open position inside the exhaust gas recirculation path 2. This device is held (openable and closable) and is fastened and fixed to an exhaust gas recirculation pipe (or an engine exhaust pipe or an engine intake pipe) using a fastener (not shown) such as a bolt. Further, a valve shaft 5 that rotates integrally with the butterfly valve 4 is slidably supported in the rotation direction in the housing 1 via bearing parts such as a bushing 31, an oil seal 32, and a ball bearing 33. A valve bearing 34 is provided. A shaft housing hole 35 extending in the central axis direction of the valve shaft 5 is provided inside the valve bearing portion 34.

  Further, when the bushing 31, the oil seal 32, and the ball bearing 33 are respectively incorporated in the shaft housing hole 35 on the inner periphery of the valve bearing portion 34, the shaft housing hole 35 further extends toward the nozzle side in the axial direction. First to third step portions 36 to 38 having restriction surfaces for restricting movement are provided. Further, impurities (for example, combustion residue and fine particles such as carbon) contained in the exhaust gas that has entered the shaft accommodating hole 35 are introduced into the nozzle side from the EGR rather than the butterfly valve 4 by using, for example, intake pipe negative pressure. A communication hole 39 for returning to the exhaust gas recirculation path on the downstream side in the gas flow direction is formed.

The bushing 31 is a sintered part (bearing part) obtained by sintering a metal material such as copper or iron, and is formed in a cylindrical shape. The bushing 31 is locked to the restriction surface of the first stepped portion 36, thereby positioning in the axial direction with respect to the valve shaft 5, and supported and fixed to the inner periphery of the valve bearing portion 34 by press fitting or the like. ing. The valve shaft 5 is slidable in the rotational direction and the axial direction inside a sliding hole formed in the bushing 31.
The oil seal 32 is, for example, a rubber seal, and is engaged with the restriction surface of the second stepped portion 37 so as to be positioned in the axial direction with respect to the valve shaft 5, and press-fitted and fixed to the inner periphery of the valve bearing portion 34. Has been. The valve shaft 5 is slidable in the rotational direction and the axial direction inside a sliding hole formed in the oil seal 32.

The ball bearing 33 is a bearing part which is provided with an annular groove on the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring, and is operated by rolling friction of a ball (rolling element) rolling on the raceway surface, and is formed in a cylindrical shape. . The ball bearing 33 is locked to the restricting surface of the third step portion 38, thereby positioning the valve shaft 5 in the axial direction, and the outer ring is press-fitted into the inner periphery of the valve bearing portion 34. The inner ring is supported and fixed to the outer periphery of the valve shaft 5 by press fitting or the like.
The housing 1 is provided with a cylindrical nozzle fitting portion 40 for fitting and holding the nozzle 3. The housing 2 is connected to a cooling water pipe 42 for flowing engine cooling water into a cooling water circulation path 41 formed, for example, in the vicinity of the valve fully closed position or around the valve bearing portion 34 or the nozzle fitting portion 40. ing. Here, 43 is a hot water plug for liquid-tightly closing the opening end of the cooling water circulation path 41.

The nozzle 3 forms a part of the exhaust gas recirculation pipe and is a cylindrical portion that accommodates the butterfly valve 4 so as to be openable and closable. The nozzle 3 is formed in a circular pipe shape from a heat-resistant material resistant to high temperatures, such as stainless steel. Yes. The nozzle 3 is fitted and held on the inner periphery of the nozzle fitting portion 40 of the housing 2 by press fitting or the like.
An exhaust gas recirculation path 2 having a bent portion 44 is formed in the middle of the nozzle 3. Here, the exhaust gas recirculation passage 2 upstream of the bent portion 44 in the EGR gas flow direction (exhaust pipe side), that is, the first exhaust gas recirculation passage 45 is a butterfly from the inlet portion toward the valve fully closed position. The valve 4 extends straight in the axial direction perpendicular to the surface direction of the upstream end face of the butterfly valve 4 (diameter direction of the butterfly valve 4) when the valve 4 is fully closed. Further, the exhaust gas recirculation path 2, that is, the second exhaust gas recirculation path 46 on the downstream side (intake pipe side) of the EGR gas flow direction with respect to the bent portion 44, that is, the second exhaust gas recirculation path 46 extends from the vicinity of the valve fully closed position toward the outlet portion. 5 extends straight in the axial direction orthogonal to the central axis of the line 5.
The seal of the seal ring 7 fitted in the seal ring groove 6 of the butterfly valve 4 when the butterfly valve 4 is fully closed is formed on the inner peripheral surface (flow passage wall surface of the housing 1) of the nozzle 3 near the valve fully closed position. A seal ring seat surface 47 is provided on which the ring sliding surface can be in close contact. The nozzle 3 is provided with a shaft through hole 49 through which the valve shaft 5 passes.

  The valve shaft 5 is formed of a heat-resistant material resistant to high temperatures, such as stainless steel, and is rotatably or slidably accommodated in a shaft accommodation hole 35 provided in the valve bearing portion 34 of the housing 1. Yes. The valve shaft 5 is a cylindrical metal member that has a circular cross section and is formed straight from one side to the other side in the axial direction. Then, one end side of the valve shaft 5 in the axial direction penetrates the shaft accommodating hole 35 of the housing 1 and the shaft through hole 49 of the nozzle 3 and projects (exposes) into the exhaust gas recirculation path 2. A valve mounting portion (shaft side fitting portion) 63 for holding and fixing the butterfly valve 4 using laser welding is provided on one end side in the axial direction of the valve shaft 5. Further, a caulking fixing portion for fixing the valve gear plate 26, which is insert-molded on the inner peripheral portion of the valve gear 24, by fixing means such as caulking is integrally formed at the other end portion in the axial direction of the valve shaft 5. ing.

  Next, details of the butterfly valve 4 of the present embodiment will be described with reference to FIGS. Here, FIGS. 2A and 2B are views showing a laser welding method of the EGR control valve.

  As described above, the butterfly valve 4 is a disk-like swash plate that is welded and fixed to the central axis of the valve shaft 5 inside the housing 1 and extends radially from the center. It has a disk-shaped part 51. An annular outer peripheral edge 52 is integrally provided on the outer diameter side of the disk-shaped portion 51 in the radial direction. A seal ring groove 6 for fitting and holding the seal ring 7 is formed on the outer peripheral end surface of the outer peripheral edge 52. A circular thick portion 53 having a plate thickness greater than that of the outer peripheral edge portion 52 is provided on the upstream end face of the disc-like portion 51. The thick portion 53 is provided near the center located on the inner diameter side in the radial direction with respect to the outer peripheral edge portion 52.

  A shaft fitting groove (concave shape) fitted to a valve mounting portion 63 which is one end portion in the axial direction of the valve shaft 5 is formed on one end surface in the plate thickness direction of the butterfly valve 4, that is, on the downstream end surface of the disc-like portion 51. A valve side fitting portion) 54 is formed. The shaft fitting groove 54 is opened only on one end surface in the plate thickness direction of the butterfly valve 4.

  Specifically, only one side of the shaft fitting groove 54 in the groove length direction (one side: right side in FIG. 2) is opened, and the other side of the shaft fitting groove 54 in the groove length direction (in FIG. 2). The left side in the figure is closed (bag-hole shape). That is, a shaft penetration opening through which the valve shaft 5 penetrates is formed on one side of the shaft fitting groove 54 in the groove length direction, and the other side of the shaft fitting groove 54 in the groove length direction. A groove wall surface is formed opposite to one end surface (shaft end surface) of the valve shaft 5 in the axial direction.

  Further, only one side of the shaft fitting groove 54 in the groove depth direction (one side: the lower side in FIG. 2A) opens, and the other side of the shaft fitting groove 54 in the groove depth direction (FIG. 2). (A) in the figure) is closed (bag hole shape). That is, a shaft insertion opening for fitting the valve shaft 5 is formed on one side of the shaft fitting groove 54 in the groove depth direction, and the other of the shaft fitting groove 54 in the groove depth direction is formed. On the side, a groove bottom surface is formed opposite to the shaft outer diameter surface orthogonal to the axial direction of the valve shaft 5. That is, the shaft fitting groove 54 does not penetrate through the both end surfaces of the disc-like portion 51 of the butterfly valve 4 so as to communicate with each other.

  Further, one end surface in the plate thickness direction of the butterfly valve 4, that is, the downstream end surface of the disc-shaped portion 51, is provided on both surfaces in the diametrical direction of the valve mounting portion 63 of the valve shaft 5 (hereinafter referred to as two first and second surfaces). Two first and second shaft guides 61 and 62 arranged to face the outer surface of the shaft are integrally provided. The first and second shaft guides 61 and 62 are triangular guides that protrude from the one end face in the plate thickness direction of the butterfly valve 4, that is, from the downstream end face of the disc-like portion 51 to the downstream side in the EGR gas flow direction. It is a wall.

  The first shaft guide 61 has a first guide wall surface facing the second shaft guide 62 with a predetermined gap (groove width of the shaft fitting groove 54) therebetween. Further, the second shaft guide 62 has a second guide wall surface facing the first guide wall surface of the first shaft guide 61 with a predetermined gap (groove width of the shaft fitting groove 54) therebetween. . The first and second guide wall surfaces of the two first and second shaft guides 61 and 62 are groove wall surfaces located on both sides of the shaft fitting groove 54 in the groove width direction (groove wall surfaces of the shaft fitting groove 54). : Hereinafter referred to as two first and second groove side surfaces).

  Then, by performing laser welding (welding process) using the laser welding apparatus 10 at the joint portion between the butterfly valve 4 and the valve shaft 5, the first and second first and second parallel lines are arranged in parallel. Two welds 11 and 12 are formed. The two parallel first and second welds 11 and 12 are formed on a vertical line perpendicular to the axial direction of the exhaust gas recirculation path 2, particularly the second exhaust gas recirculation path 46. In addition, as shown in FIG. 2, the two parallel first and second welded portions 11 and 12 have a range in which the plate thickness of the butterfly valve 4 is thick (range of an axis passing through the outer diameter surface of the thick portion 53. : S).

The first welding portion 11 is formed at a first joint location between the first groove side surface of the first shaft guide 61 of the butterfly valve 4 and the first shaft outer diameter surface of the valve mounting portion 63 of the valve shaft 5. It is formed linearly along the groove length direction of the shaft fitting groove 54 of the valve 4 and the central axis direction of the valve mounting portion 63 of the valve shaft 5.
The second welded portion 12 is formed at a second joint location between the second groove side surface of the second shaft guide 62 of the butterfly valve 4 and the second shaft outer diameter surface of the valve mounting portion 63 of the valve shaft 5. It is formed linearly along the groove length direction of the shaft fitting groove 54 of the valve 4 and the central axis direction of the valve mounting portion 63 of the valve shaft 5.

[Production Method of Example 1]
Next, a manufacturing method of the EGR control valve according to the present embodiment, in particular, an assembling method for assembling the valve assembly (valve component parts) such as the butterfly valve 4 and the valve shaft 5 to the housing 1 based on FIG. 1 to FIG. Briefly described. Here, FIGS. 2 and 3 are views showing a laser welding method of the EGR control valve.

  As shown in FIG. 3, the laser welding apparatus 10 of the present embodiment uses two first and second laser outputs output from the two first and second laser oscillators 14 and 15 controlled by the control circuit 13. The butterfly valve 4 is laser welded to the valve shaft 5 inside the housing 1 by condensing with a lens or the like in the second welding heads 16 and 17 and irradiating the two first and second joints with a laser beam. It is a device to do.

As shown in FIGS. 2 and 3, the two first and second laser oscillators 14 and 15 and the two first and second welding heads 16 and 17 are arranged in the direction of the central axis of the valve mounting portion 63 of the valve shaft 5. Or it can move in the direction of the white arrow in FIG. 2 along the groove length direction of the shaft fitting groove 54 of the butterfly valve 4. As the first and second laser oscillators 14 and 15, semiconductor laser oscillators having a laser output of about 700 to 900 W are used. Further, as the first and second laser oscillators 14 and 15, a pulse YAG (yttrium, aluminum, garnet) laser oscillator or a CO ₂ laser oscillator may be used.

  Further, the laser welding apparatus 10 presses the groove bottom surface on the other side in the groove depth direction of the shaft fitting groove 54 of the butterfly valve 4 against the surface of the valve mounting portion 63 of the valve shaft 5 against the butterfly valve 4. It has a welding jig 18 that applies a load in the direction. The welding jig 18 can reciprocate in a direction orthogonal to the diameter direction of the butterfly valve 4.

  First, the nozzle 3 is assembled to the inner periphery of the nozzle fitting portion 40 of the housing 1 by press fitting or the like (press fitting and fixing). Next, the bushing 31 is inserted from the opening on the right side (gear side) of the shaft accommodation hole 35 of the housing 1 to a position where the bushing 31 comes into contact with the regulation surface of the first step portion 36, and the valve bearing portion 34 of the housing 1 is inserted. It is assembled to the inner periphery by press fitting (fixed by press fitting). Next, the oil seal 32 is inserted from the opening of the shaft receiving hole 35 of the housing 1 to a position where it abuts on the restriction surface of the second stepped portion 37, and is press-fitted to the inner periphery of the valve bearing portion 34 of the housing 1. Assemble by pressing etc. (press fit). Next, the inner ring of the ball bearing 33 is fitted and held (press-fitted and fixed) at a predetermined position on the outer periphery of the valve shaft 5 by press-fitting or the like.

  Next, the valve shaft 5 is inserted from the opening of the shaft housing hole 35 of the housing 1 in the order of the sliding hole of the oil seal 32, the sliding hole of the bushing 31, and the shaft through hole 49 of the nozzle 3. A valve mounting portion 63 that is one end side in the axial direction is projected into the exhaust gas recirculation path 2 formed in the nozzle 3. At this time, the outer ring of the ball bearing 33 is locked at a position where it comes into contact with the restriction surface of the third stepped portion 38 of the valve bearing portion 34. Thus, the valve shaft 5 in which the inner ring of the ball bearing 33 is press-fitted and fixed is positioned in the axial direction of the shaft receiving hole 35 of the housing 1, that is, assembled at a predetermined position. The amount of protrusion to the inside of the exhaust gas recirculation path 2 is a predetermined protrusion amount.

On the other hand, the seal ring 7 is fitted into the seal ring groove 6 formed on the outer peripheral end surface of the butterfly valve 4, and the seal ring 7 is attached to the outer periphery of the butterfly valve 4.
Next, the butterfly valve 4 having the seal ring 7 fitted and held in the seal ring groove 6 is assembled to the welding jig 18. At this time, the thick portion 53 provided on the upstream end face of the disc-like portion 51 of the butterfly valve 4 is fitted into the circular recess 19 of the welding jig 18, so that the butterfly valve 4 is fitted to the welding jig 18. Is chucked (detachably fitted and held).

Next, the butterfly valve 4 held by the welding jig 18 is connected to the exhaust gas recirculation path 2 upstream of the bent portion 44 of the nozzle 3 in the EGR gas flow direction (exhaust pipe side), that is, the first exhaust gas recirculation path. The butterfly valve 4 is inserted into the nozzle 3 from the upstream side in the axial direction of 45 (inlet part of the first exhaust gas recirculation path 45). At this time, the load in the direction of the arrow is applied to the butterfly valve 4 by moving the welding jig 18 along the seal ring sheet surface 47 of the nozzle 3 in the direction of the white arrow in FIG.
Here, the butterfly valve 4 held by the welding jig 18 is disposed on a vertical line perpendicular to the axial direction of the first exhaust gas recirculation path 45, as shown in FIGS. That is, the butterfly valve 4 is maintained at the fully closed opening degree that is closed at the valve fully closed position.

Further, the groove length direction of the shaft fitting groove 54 of the butterfly valve 4 is inclined by a predetermined inclination angle with respect to the central axis direction of the valve mounting portion 63 of the valve shaft 5.
Accordingly, when the welding jig 18 is moved in the direction of the white arrow in FIG. 3 along the seal ring seat surface 47 of the nozzle 3, the shaft fitting of the butterfly valve 4 is fitted to the valve mounting portion 63 of the valve shaft 5. The mating groove 54 is fitted. At this time, since the welding jig 18 applies a load in the direction of the arrow to the butterfly valve 4, the groove bottom surface of the shaft fitting groove 54 of the butterfly valve 4 is positioned on the valve shaft 5 as shown in FIG. 3. The valve mounting portion 63 is pressed against the outer surface of the shaft.

  Next, the welding process of a present Example is demonstrated. In the welding process, using the laser outputs from the two first and second laser oscillators 14 and 15, the first groove side surface of the first shaft guide 61 of the butterfly valve 4 and the first of the valve mounting portion 63 of the valve shaft 5 are used. The first joint location with the outer diameter surface of the shaft and the second joint location between the second groove side surface of the second shaft guide 62 of the butterfly valve 4 and the second shaft outer diameter surface of the valve mounting portion 63 of the valve shaft 5 are simultaneously provided. By heat-melting, the two first and second joint locations are laser welded simultaneously. Thus, two parallel first and second welds 11 and 12 are formed at the two first and second joint locations of the butterfly valve 4 and the valve shaft 5.

  Specifically, as shown in FIGS. 2 and 3, first, the laser beams collected by the two first and second welding heads 16 and 17 are directed to the EGR gas flow direction from the bent portion 44 of the nozzle 3. From the downstream side (intake pipe side) of the exhaust gas recirculation path 2, that is, the downstream side in the axial direction of the second exhaust gas recirculation path 46 (the outlet portion of the second exhaust gas recirculation path 46), point A (the two first The second shaft guides 61 and 62 are irradiated to the disk-shaped part side portion and the base). At this time, the irradiation direction of the laser beam is perpendicular to the groove length direction of the shaft fitting groove 54 of the butterfly valve 4 and the central axis direction of the valve mounting portion 63 of the valve shaft 5.

  Thereafter, the laser beam is scanned linearly along the outer diameter surfaces of the first and second shafts of the valve shaft 5 in the direction of the white arrow in FIG. 2, and the point B (two first and second shaft guides 61) is scanned. , 62 tip, ridge line). At this time, it is desirable that the first and second groove side surfaces of the butterfly valve 4 and the first and second shaft outer diameter surfaces of the valve shaft 5 are in close contact with each other. A slight gap may be formed between the two-groove side surface and the first and second shaft outer diameter surfaces of the valve shaft 5. The first and second groove side surfaces of the butterfly valve 4 and the first and second shaft outer diameter surfaces of the valve shaft 5 may be fitted to each other by clearance fitting or slight press fitting.

  By performing the above welding process, the butterfly valve 4 in the housing 1 is inclined to the valve mounting portion 63 of the valve shaft 5 with a predetermined inclination angle with respect to the central axis of the valve shaft 5. It is fixed by welding (holding). Thereafter, the laser welding apparatus 10 is detached from the housing 1 and the nozzle 3 with an integral part in which a valve assembly (valve component part) such as the butterfly valve 4 and the valve shaft 5 is assembled, and the other end of the valve shaft 5 in the axial direction is removed. An EGR control valve is manufactured by, for example, caulking and fixing a valve gear plate 26 that is insert-molded to the valve gear 24.

[Operation of Example 1]
Next, the operation of the exhaust gas recirculation device of this embodiment will be briefly described with reference to FIGS.

The ECU controls the electric motor 9 so that the EGR amount detected by the EGR amount sensor (actual EGR opening of the EGR control valve) and the target EGR opening set corresponding to the operating state of the engine substantially coincide. Adjust the power supply.
When electric power is supplied to the electric motor 9, the motor shaft 21 of the electric motor 9 rotates. Then, the driving force (motor output shaft torque) of the electric motor 9 is transmitted to the valve shaft 5 through the gear reduction mechanism. Then, the valve shaft 5 rotates by a predetermined rotation angle, and the butterfly valve 4 is rotationally driven (valve opening drive) in a direction (valve opening operation direction) that opens from the valve fully closed position to the valve fully open position.
Thereby, a part of the exhaust gas (high temperature fluid such as EGR gas) flowing out from the combustion chamber for each cylinder of the engine is formed in the exhaust gas recirculation pipe from the exhaust passage formed in the engine exhaust pipe. In the intake passage formed in the engine intake pipe through the return path, the exhaust gas return path 2 (first and second exhaust gas return paths 45 and 46) of the housing 1, and the exhaust gas return path formed in the exhaust gas return pipe Recirculated.

On the other hand, when the butterfly valve 4 is fully closed so that the actual EGR opening degree of the butterfly valve 4 of the EGR control valve becomes the valve fully closed position, the supply of electric power to the electric motor 9 is stopped. Alternatively, the supply of electric power to the electric motor 9 is limited. Thereby, the butterfly valve 4 is returned to the valve fully closed position by the urging force (spring load) of the coil spring 8.
As a result, the seal ring sliding surface of the seal ring 7 mounted on the outer periphery of the butterfly valve 4 sticks to the seal ring seat surface 47 of the nozzle 3 by the tension in the diameter increasing direction of the seal ring itself. The ring sliding surface comes into close contact with the seal ring sheet surface 47 of the nozzle 3. Therefore, the gap between the outer peripheral end surface of the butterfly valve 4 and the seal ring seat surface 47 of the nozzle 3 is completely sealed. Thereby, when the butterfly valve 4 is held and fixed in the fully closed position of the valve, that is, when the butterfly valve 4 is fully closed, the leakage of the EGR gas is surely suppressed, so that the EGR gas does not enter the intake air.

[Effect of Example 1]
As described above, in the EGR control valve used in the exhaust gas recirculation device of the present embodiment, each of the first and second shaft fitting grooves 54 (first and second shaft guides 61 and 62) of the butterfly valve 4 is provided. The second groove side surface and the first and second shaft outer diameter surfaces of the valve mounting portion 63 of the valve shaft 5 are laser welded by using the laser welding apparatus 10, and two butterfly valves 4 and the valve shaft 5 are connected to each other. 1. The welding process which forms the 2nd parallel 1st, 2nd welding part 11 and 12 in the 2nd junction location is provided.
Even if there is a portion that cannot be welded in the fitting portion between the shaft fitting groove 54 of the butterfly valve 4 and the valve mounting portion 63 of the valve shaft 5 in this welding process, the butterfly valve 4 and the valve shaft 5 Since the fitting portion is constituted by the first and second groove side surfaces of the shaft fitting groove 54 and the first and second shaft outer diameter surfaces of the valve mounting portion 63, the disc-like shape of the butterfly valve 4 is formed. There is no through hole penetrating the both end surfaces of the portion 51 so as to communicate with each other. Therefore, when the butterfly valve 4 is fully closed, high temperature fluid such as EGR gas does not leak through the portion of the fitting portion where welding cannot be performed, and the EGR gas leaks when the butterfly valve 4 is fully closed. Can be prevented.

  Further, in the welding process, two rows of parallel first and second welded portions 11 along the groove length direction of the shaft fitting groove 54 of the butterfly valve 4 and the central axis direction of the valve mounting portion 63 of the valve shaft 5, 12 is formed. Also, the two parallel first and second welds 11 and 12 are formed in a straight line so as to be positioned on a perpendicular line to the axial direction of the exhaust gas recirculation path 2. As a result, the weld lengths of the two parallel first and second welds 11 and 12 are set to the groove length direction of the shaft fitting groove 54 of the butterfly valve 4 and the central axis of the valve mounting part 63 of the valve shaft 5. It can be long in substantially the same direction as the direction and long in the direction perpendicular to the axial direction of the exhaust gas recirculation path 2. That is, since a sufficient effective welding length can be ensured, the coupling performance (joining performance) of the first and second joints between the butterfly valve 4 and the valve shaft 5 can be improved. There is no fear that the butterfly valve 4 will fall off. Further, in the welding process in which the first and second joints between the butterfly valve 4 and the valve shaft 5 are laser-welded using the laser welding apparatus 10, it is only necessary to scan the laser beam linearly, as in the prior art. In addition, since it is not necessary to scan the laser beam in a substantially U shape (or semicircular elliptical arc shape), the welding operation of the first and second joints between the butterfly valve 4 and the valve shaft 5 is facilitated, and EGR control is performed. The productivity of the valve can be improved.

  Further, since the first and second joints of the butterfly valve 4 and the valve shaft 5 are laser welded at the same time, any one of both sides of the shaft fitting groove 54 of the butterfly valve 4 in the groove width direction is welded. It is not pulled to one side, and the position of the butterfly valve 4 does not deviate from the normal position. That is, the positional accuracy of the butterfly valve 4 with respect to the valve mounting portion 63 of the valve shaft 5 can be improved. Further, since two rows of the first and second welded portions 11 and 12 that are parallel to each other can be formed at the same time, it is possible to shorten the welding work time at the first and second joints between the butterfly valve 4 and the valve shaft 5, and EGR The productivity of the control valve can be improved.

  In addition, since the first and second joints of the butterfly valve 4 and the valve shaft 5 are simultaneously laser welded within the range (S) where the butterfly valve 4 is thick, the plate thickness of the butterfly valve 4 is the same. It is possible to prevent the round outer peripheral edge 52 of the butterfly valve 4 from being deformed by the welding heat and reducing the roundness of the outer peripheral edge 52 of the butterfly valve 4. Thereby, even when the seal ring 7 that is a C-shaped metal ring that cannot compensate for the deterioration of the roundness of the disc-like portion 51 of the butterfly valve 4 is employed, the seal ring 7 is inclined. It is not attached to the seal ring groove 6 in a state. Therefore, the annular clearance between the seal ring seat surface 47 of the nozzle 3 and the outer peripheral end surface of the butterfly valve 4 when the butterfly valve 4 is fully closed becomes an appropriate value (or zero), and the seal ring when the butterfly valve 4 is fully closed. 7 can be improved. As a result, the seal ring sliding surface of the seal ring 7 comes into close contact with the seal ring seat surface 47 of the nozzle 3, so that the amount of EGR gas leakage when the butterfly valve 4 is fully closed can be reduced.

[Modification]
In this embodiment, the nozzle 3 is fitted and held on the inner periphery of the nozzle fitting portion 40 of the housing 1, and the butterfly valve 4 is accommodated in the nozzle 3 so as to be openable and closable. The butterfly valve 4 may be accommodated directly in the valve accommodating portion so as to be freely opened and closed. In this case, the nozzle 3 becomes unnecessary, and the number of parts and the number of assembling steps can be reduced.

  In the present embodiment, the valve driving device for driving the butterfly valve 4 to open or close is constituted by an electric actuator including an electric motor 9 and a power transmission mechanism (for example, a gear reduction mechanism). The valve drive device that drives to open or close the valve may be configured by a negative pressure actuated actuator having an electromagnetic or electric negative pressure control valve, or an electromagnetic actuator having an electromagnet including a coil.

  Note that the seal ring groove (annular groove) 6 may not be provided on the outer peripheral end face of the butterfly valve 4. Further, the seal ring 7 may not be attached to the outer peripheral end face of the butterfly valve 4. In this case, the seal ring 7 becomes unnecessary, and the number of parts and the number of assembling steps can be reduced. Further, the coil spring (valve urging means) 8 for urging the butterfly valve 4 of the EGR control valve in the valve closing direction or the valve opening direction may not be provided. In this case, the coil spring 8 is not necessary, and the number of parts and assembly man-hours can be reduced.

  In this embodiment, the fluid control valve of the present invention is applied to an EGR control valve that controls the flow rate of a high-temperature fluid such as EGR gas. However, the fluid control valve of the present invention is sucked into the combustion chamber of the engine. An intake control valve such as a throttle valve that controls the intake air amount, an exhaust control valve that controls the amount of exhaust gas discharged from the combustion chamber of the engine, an idle speed control valve that controls the intake air amount that bypasses the throttle valve, etc. You may apply to a fluid flow control valve.

  In this embodiment, the fluid control valve of the present invention is applied to a fluid flow control valve such as an EGR control valve. However, the present invention is not limited to such a fluid flow control valve. The present invention may be applied to a fluid flow path switching valve and a fluid pressure control valve. Further, the fluid control valve of the present invention may be applied to an intake flow control valve such as a tumble flow control valve or a swirl flow control valve, an intake variable valve that changes the passage length or passage cross-sectional area of the intake passage, and the like. A gasoline engine may be used as the engine.

  In this embodiment, the housing in which the fluid flow path is formed is constituted by the housing 1 connected in the middle of the exhaust gas recirculation pipe. However, the housing is a part of the engine intake pipe or the engine exhaust pipe. You may comprise by the housing which comprises a part. In this embodiment, an example in which the butterfly valve 4 is applied as a valve has been described. However, as a valve, other valves such as a plate-type valve, a poppet-type valve, a double poppet-type valve, a rotary-type valve, and a flap-type valve are used. May be used. Moreover, you may apply a valve to the valve body of the fluid control valve which controls fluids, such as gas and a liquid.

  In the present embodiment, the two first and second joints of the butterfly valve 4 and the valve shaft 5 are laser welded by using the laser welding apparatus 10, but the two first joints of the butterfly valve 4 and the valve shaft 5 are used. The first and second joints may be TIG welded, MIG welded, electron beam welded, or arc welded using various welding means.

It is sectional drawing which showed the EGR control valve (Example 1). (A), (b) is sectional drawing and the top view which showed the laser welding method of the EGR control valve (Example 1). It is explanatory drawing which showed the laser welding method of the EGR control valve (Example 1). (A), (b) is the top view and sectional drawing which showed the laser welding method of the EGR control valve (conventional technique).

Explanation of symbols

1 Housing 2 Exhaust gas recirculation path (fluid flow path)
3 Nozzle 4 Butterfly valve 5 Valve shaft 6 Seal ring groove (annular groove)
7 Seal ring 9 Electric motor 10 Laser welding equipment (welding means)
11 First weld (two rows of parallel welds)
12 Second weld (two rows of parallel welds)
52 Outer peripheral edge portion of butterfly valve 54 Shaft fitting groove of butterfly valve 61 First shaft guide of butterfly valve 62 Second shaft guide of butterfly valve 63 Valve mounting portion of valve shaft

Claims (8)

(A) a housing having a fluid flow path formed therein;
(B) a shaft rotatably accommodated in the housing;
(C) A method of manufacturing a fluid control valve including a swash plate-like valve that is held and fixed to the shaft using welding means in a state of being inclined with respect to the central axis of the shaft inside the housing. Because
The valve has a fitting groove fitted to the shaft,
The fitting groove is opened only at one end surface in the plate thickness direction of the valve,
Welding the groove wall surface of the fitting groove and the shaft using the welding means, and forming a welding portion between the valve and the shaft ;
The valve is a disc-shaped butterfly valve extending from the center to the outer diameter side in the radial direction,
The butterfly valve has an annular outer peripheral edge on the outer diameter side in the radial direction, and is closer to the center located on the inner diameter side in the radial direction than the outer peripheral edge than the outer peripheral edge. It has a thick part with a thick plate,
The method for manufacturing a fluid control valve, wherein the welding means welds the shaft and a groove wall surface of the fitting groove within a range where the butterfly valve is thick . In the manufacturing method of the fluid control valve according to claim 1,
The method for manufacturing a fluid control valve, wherein the welded portion is formed linearly along a central axis direction of the shaft or a groove length direction of the fitting groove. In the manufacturing method of the fluid control valve according to claim 1 or 2,
The method of manufacturing a fluid control valve, wherein the welded portion is formed on a vertical line perpendicular to the axial direction of the fluid flow path. In the manufacturing method of the fluid control valve according to any one of claims 1 to 3,
2. The method for manufacturing a fluid control valve according to claim 1, wherein the welded portions are two rows of parallel welded portions formed in a straight line in parallel. In the manufacturing method of the fluid control valve according to claim 4,
The two rows of parallel welds are formed by simultaneously welding both sides in the width direction of the shaft and both sides in the groove width direction of the fitting groove of the valve. . (A) a housing having a fluid flow path formed therein;
(B) a shaft rotatably accommodated in the housing;
(C) a swash plate-like valve that is held and fixed to the shaft using welding means in a state inclined with respect to the central axis of the shaft inside the housing;
A fluid control valve comprising:
The valve has a fitting groove fitted to the shaft,
The fitting groove is opened only at one end surface in the plate thickness direction of the valve,
The valve is a disc-shaped butterfly valve extending from the center to the outer diameter side in the radial direction,
The butterfly valve has an annular outer peripheral edge on the outer diameter side in the radial direction, and is closer to the center located on the inner diameter side in the radial direction than the outer peripheral edge than the outer peripheral edge. A fluid control valve characterized by having a thick portion having a large plate thickness . The fluid control valve according to claim 6 .
The shaft is formed in a circular cross section,
The fitting groove is fluid control valve characterized in that it have a groove depth or groove width of about radial dimension of the shaft. The fluid control valve according to claim 6 .
A seal ring that seals a gap between a flow path wall surface of the housing and an outer peripheral end surface of the butterfly valve when the butterfly valve is fully closed;
The said butterfly valve has the annular groove which mounts | wears with the said seal ring in this outer peripheral end surface perimeter, The fluid control valve characterized by the above-mentioned .

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