JP2019078305A - Poppet valve - Google Patents

Abstract

To provide a poppet valve capable of suppressing a positional deviation of a shaft portion to be welded to a valve body.SOLUTION: An EGR valve 1 includes: a seat 4; a valve 5 which abuts on and separates from the seat 4, is equipped with a bottom portion 41 and a side wall portion 42 provided so as to rise from an edge portion of the bottom portion 41, and has a shape opening on a side opposite to the bottom portion 41; a shaft 6 which is inserted in a through-hole 44 of the bottom portion 41 of the valve 5 and is welded with the bottom portion 41; and a step motor 8 which drives the shaft 6 in an axial direction of the shaft 6. A ratio R1 of a plate thickness/a shaft diameter is set to be a predetermined ratio or more, and the predetermined ratio is decided according to a material of the valve 5.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a poppet valve in which a valve body moves in the axial direction by driving a shaft, for example, to a poppet valve that controls the flow rate of EGR gas.

  As a prior art, Patent Document 1 discloses a valve device that adjusts the flow rate of fluid flowing in a housing by opening and closing a control valve. In this valve device, the valve head provided to the adjusting valve is formed into an umbrella shape by pressing. And this valve head is provided with a lightening part, and a connecting part which is extended from the lightening part and formed in a substantially cylindrical shape so as to form an insertion hole for press-fitting the shaft part.

JP, 2014-173706, A

  In the valve device disclosed in Patent Document 1, the valve head is formed with a connection portion into which the shaft portion is press-fitted. However, if the connecting portion is not formed on the valve head, the manufacturing process can be simplified because it is not necessary to extend the connecting portion from the lightening when forming the valve head by press processing. Therefore, it is conceivable to weld the shaft portion to the valve head without forming a connecting portion in which the shaft portion is press-fitted to the valve head. And, when welding the shaft to the valve head (valve body) like this, if the plate thickness of the valve head is thin, the amount of deformation of the valve head at the time of welding becomes large, and the position of the shaft after welding There is a risk of misalignment.

  Then, this indication is made in order to solve an above-mentioned problem, and it aims at providing a poppet valve which can control position gap of an axial part welded with a valve body.

  One aspect of the present disclosure made to solve the above problems is a valve seat, and a sidewall that abuts and is separated from the valve seat, and is provided so as to rise from a bottom portion and an edge of the bottom portion. A valve body having a shape in which the side opposite to the bottom is opened, a shaft inserted into the through hole of the bottom of the valve and welded to the bottom, and the shaft In the poppet valve having a step motor driven in the axial direction of the part, the ratio of the thickness of the bottom of the valve body to the diameter of the shaft is set to a predetermined ratio or more, and the predetermined ratio is the valve body It is characterized in that it is determined depending on the material of

  According to this aspect, the deformation amount of the valve body produced when welding the valve body and the shaft portion can be obtained by securing the size of the plate thickness of the bottom portion of the valve body to a predetermined ratio or more with respect to the diameter of the shaft portion. It can be kept small. Therefore, positional deviation of the shaft portion welded to the valve body can be suppressed. And, by setting the plate thickness of the bottom of the valve according to the material of the valve, it is possible to suppress the positional deviation of the shaft regardless of the material of the valve.

  In the above aspect, preferably, the material of the valve body is iron or a material containing iron, and the predetermined ratio is set between 0.55 and 0.65.

  According to this aspect, in the valve body made of iron or iron, it is possible to reduce the amount of deformation of the valve body immediately after welding, and to reduce the amount of return of the valve body when the weld is solidified. Therefore, it is possible to more reliably suppress the positional deviation of the shaft portion welded to the valve body.

  In the above aspect, the mass of the valve body is smaller than a predetermined mass, and in the predetermined mass, the frequency of the valve body when vibration is applied to the poppet valve is higher than the upper limit value of the resonance frequency band. It is preferable that the value be set to a high value.

  According to this aspect, by setting the upper limit of the mass of the valve body, it is possible to suppress the valve body from being detached from the shaft portion by vibration.

  In the above aspect, the through hole is formed by punching and pressing, and the axial length of the through hole with respect to the shear surface formed on the inner wall of the through hole is predetermined with respect to the thickness of the bottom portion. Preferably, the predetermined length is a value that can equalize the heat transfer from the shaft to the bottom when welding the bottom and the shaft of the valve body.

  According to this aspect, the heat conduction to the valve body at the time of welding can be made uniform, so that the deformation of the valve body at the time of welding can be suppressed.

  In the above aspect, the predetermined ratio is preferably 49%.

  According to this aspect, since the heat conduction to the valve body at the time of welding can be made more uniform, the deformation of the valve body at the time of welding can be suppressed.

  In the above aspect, the thickness of the side wall portion is preferably smaller than the thickness of the bottom portion.

  According to this aspect, the weight of the valve can be reduced.

  In the above aspect, the poppet valve is preferably an EGR valve that regulates the flow rate of the EGR gas flowing from the exhaust passage of the engine to the intake passage.

  According to the poppet valve of the present disclosure, it is possible to suppress positional deviation of the shaft portion welded to the valve body.

It is a sectional view of an EGR valve of this embodiment. It is sectional drawing of the valve | bulb and the front-end | tip part of a shaft before welding in this embodiment. It is a figure which shows the evaluation result regarding the ratio of plate thickness / shaft diameter, and the shaft position after welding. It is a figure which shows the evaluation result regarding the welding energy and the shaft position after welding. It is a figure explaining the deformation | transformation of the valve | bulb immediately after welding in a product of this embodiment, and the return of the valve at the time of solidification of a welding part. It is a figure which shows the evaluation result regarding the mass of a valve | bulb, and the frequency of a valve | bulb. It is a figure which shows the evaluation result regarding the ratio of the length / plate | board thickness of the shear surface of an insertion hole, and the shaft position after welding. It is a figure explaining the deformation | transformation of the valve | bulb immediately after welding in a comparative product, and the return of the valve | bulb at the time of solidification of a welding part.

  An EGR valve 1 which is an embodiment of a poppet valve according to the present disclosure will be described in detail with reference to the drawings.

  The EGR valve 1 shown in FIG. 1 is provided in an EGR passage (not shown) that causes part of exhaust gas discharged from the engine to flow to the intake passage as EGR gas, and is used to adjust the EGR gas flow rate.

  As shown in FIG. 1, the EGR valve 1 has a poppet valve structure, and a housing 2, an EGR gas flow path 3 formed in the housing 2, and a seat 4 (valve A seat 5), a valve 5 (valve body) provided so as to be able to be seated (abut against and separated from the seat 4) on the seat 4 and forming a metering portion of the EGR gas between the seat 4 and the seat 4. A shaft 6 (valve shaft) provided with a valve 5 at one end for reciprocating movement (stroke movement) relative to 4 and an output shaft 7 for axially reciprocating movement (stroke movement) of the shaft 6 together with the valve 5 And a step motor 8 as drive means for rotating the motor. The EGR valve 1 is configured to adjust the EGR gas flow rate in the flow path 3 by moving the valve 5 relative to the seat 4 by the step motor 8 to change the opening area of the measurement unit.

  The shaft 6 is provided between the output shaft 7 and the valve 5 and is disposed vertically penetrating the housing 2 in FIG. The valve 5 is fixed to one end of the shaft 6 and has an umbrella shape, and the outer peripheral surface 45 (see FIG. 2) is in contact with or separated from the seat 4. At the other end of the shaft 6, a spring receiver 9 is integrally provided. Between the housing 2 and the shaft 6, there are provided a first thrust bearing 10 and a second thrust bearing 11 arranged in series for supporting the shaft 6 so as to be movable (stroke movable) in its axial direction. . Each thrust bearing 10, 11 has a substantially cylindrical shape.

  In the present embodiment, as shown in FIG. 2, the valve 5 is formed to have a bottom 41 and a side wall 42 which is provided to rise from the edge of the bottom 41 so that the side facing the bottom 41 is open. It is done. More specifically, the valve 5 is formed in an umbrella shape so as to have an opening 43 formed on the inner side of the inner wall surface 5a formed of the bottom 41 and the side wall 42 and having an opening on the side opposite to the bottom 41. ing. "Umbrella-like" in the present embodiment has a disk-like shape extending horizontally from the center of the valve 5 and being bent in the axial direction at the outer edge of the disk-like shape. The material of the valve 5 is iron or a material containing iron (for example, stainless steel (for example, SUS304)). The shaft 6 is inserted into the through hole 44 of the bottom 41 of the valve 5 and welded to the bottom 41. The material of the shaft 6 is iron or a material containing iron (for example, stainless steel (for example, SUS304)).

  The step motor 8 includes a stator 22 including a coil 21, a magnet rotor 23 provided inside the stator 22, and an output shaft 7 provided at the center of the magnet rotor 23. These members 7, 21 to 23 and the like are molded and covered by a resin casing 24. The casing 24 is integrally formed with a laterally projecting connector 25. The connector 25 is provided with a terminal (not shown) extending from the coil 21.

  The output shaft 7 has an external thread 7a on the outer periphery. The upper end of the output shaft 7 is connected to a spring receiver 9 provided at the tip of the shaft 6. The magnet rotor 23 includes a rotor main body 27 and a cylindrical plastic magnet 28 integrally provided on the outer periphery of the rotor main body 27. A first radial bearing 29 is provided between the upper end portion of the rotor body 27 and the casing 24. A second radial bearing 30 is provided on the inner periphery of the lower end portion of the plastic magnet 28 with the first thrust bearing 10. The magnet rotor 23 is rotatably supported inside the stator 22 by the upper and lower radial bearings 29, 30. At the center of the rotor body 27, a female screw 27a to be screwed to the male screw 7a of the output shaft 7 is formed. A first compression spring 31 is provided between the magnet rotor 23 and the lower second radial bearing 30. A second compression spring 32 is provided between the spring bearing 9 at the upper end of the shaft 6 and the second radial bearing 30 for biasing the shaft 6 toward the magnet rotor 23.

  As shown in FIG. 1, in the fully closed state in which the valve 5 is seated on the seat 4, the magnet rotor 23 rotates in one direction, whereby the male screw 7 a of the output shaft 7 and the female screw 27 a of the rotor main body 27 are screwed. Due to the relationship, the output shaft 7 travels in the downward direction in FIG. 1 which is a thrust direction while rotating in one direction against the biasing force of the second compression spring 32. The stroke movement of the output shaft 7 causes the valve 5 to stroke in the downward direction in FIG. 1 together with the shaft 6, and the valve 5 opens away from the seat 4.

  On the other hand, in the fully open state where the valve 5 is fully separated from the seat 4, the magnet rotor 23 rotates in the opposite direction, whereby the screwing relationship between the male screw 7a of the output shaft 7 and the female screw 27a of the rotor main body 27 The biasing force of the second compression spring 32 causes the output shaft 7 to rotate in the opposite direction, and strokes upward in FIG. 1 which is the thrust direction. The stroke movement of the output shaft 7 causes the valve 5 to stroke in the upward direction in FIG. 1 together with the shaft 6, and the valve 5 approaches the seat 4 and closes.

  Further, a substantially cylindrical lip seal 15 for sealing between the housing 2 and the shaft 6 is provided adjacent to the second thrust bearing 11 between the housing 2 and the shaft 6. The housing 2 is provided with a seat 4 for seating the valve 5.

  In the present embodiment, the shaft 6 is inserted into the through hole 44 (see FIG. 2) of the bottom 41 (see FIG. 2) of the valve 5 and welded to the bottom 41. This welding is performed, for example, by TIG welding, and is performed by disposing an electrode on the side of the tip 51 (see FIG. 2) of the shaft 6.

  In the present embodiment, the valve 5 and the shaft 6 are welded in a state where the shaft 6 is energized and held by the step motor 8. At this time, since there is a gap in meshing between the external thread 7a of the output shaft 7 and the internal thread 27a of the rotor main body 27, the magnet rotor 23 rotates with respect to the stator 22 by the force acting at the time of welding. The shaft 6 may move axially in order to obtain

  Therefore, as shown in FIG. 8, after the valve 5 is deformed in the (-) direction (direction of the step motor 8) immediately after welding, when the weld portion solidifies, the valve 5 is in the (+) direction (the step motor 8 is Returning to the opposite direction, the shaft 6 tends to be displaced in the axial direction accordingly. Then, when the positional deviation amount is large, the valve opening step (the number of steps of the step motor 8 required from the fully closed state to the valve open state) deviates from the standard toward the larger number of steps, and the EGR valve 1 May not open in a predetermined step. Then, when the valve opening step deviates from the predetermined standard as described above, there is a possibility that the EGR valve 1 can not be adjusted to flow the EGR gas of the required flow rate. Therefore, it is desirable to suppress the displacement of the shaft 6 by suppressing the amount of deformation of the valve 5 immediately after welding.

  Therefore, in the present embodiment, the plate thickness Tv of the bottom portion 41 of the valve 5 is set at a ratio to the shaft diameter Ds (diameter of the shaft 6). That is, the ratio R1 (plate thickness axis diameter ratio) of the plate thickness / shaft diameter, which is the ratio of the plate thickness Tv to the shaft diameter Ds, is set to a predetermined value or more. The predetermined value is determined depending on the material of the valve 5. In the present embodiment, since the material of the valve 5 is iron or a material containing iron, the predetermined value is set between 0.55 and 0.66.

  Here, the applicant made an evaluation to investigate the relationship between the thickness R / shaft diameter ratio R1 and the position (shaft position) of the shaft 6 after welding. At the time of welding of the valve 5 and the shaft 6, welding is started in a state where the shaft 6 is protruded from the valve 5 by a predetermined number of steps of the step motor 8 while bringing the seat 4 and the valve 5 into contact. And in evaluation, position "0" of the shaft 6 at the time of the start of this welding was made into the position of the upper limit of the target position of the shaft 6 after welding. The target position is a position at which the deviation of the valve opening step does not occur if the position of the shaft 6 after welding is within the range of the target position.

  In the evaluation, the shaft diameter Ds was set to φ4 mm. Further, as the valve 5, the first comparative product, the second comparative product, and the product of this embodiment were used. Then, for the first comparative product, the plate thickness Tv was set to 1.5 mm, and the plate thickness / shaft diameter ratio R1 was set to 0.375. In the second comparative product, the plate thickness Tv was 2.0 mm, and the ratio R1 of plate thickness / shaft diameter was 0.500. Further, for the product of this embodiment, the thickness Tv is 2.5 mm, and the ratio R1 of thickness / shaft diameter is 0.625.

  And as a result of evaluation, as shown in FIG. 3, in the 1st comparative product and the 2nd comparative product, the position of the shaft 6 after welding deviated from the target position. The reason is considered as follows. First, in the first comparative product and the second comparative product, since the plate thickness Tv is small and the ratio R1 of the plate thickness / shaft diameter is small, as shown in FIG. At the start, the amount of deformation in the direction opposite to the direction in which the shaft 6 is protruded from the valve 5 is large. Then, along with this, the return amount of the valve 5 in the (+) direction (the direction in which the shaft 6 protrudes from the valve 5 at the start of welding) when the weld is solidified also becomes large. Therefore, as a result, it is considered that the position of the shaft 6 after welding returns in the (+) direction from the position “0” of the shaft 6 at the start of welding, and deviates from the target position.

  Then, the entire valve 5 including the welded portion is deformed in the (+) direction after welding so that the valve 5 tends to move in a direction away from the seat 4. In addition, since the upper end surface of the valve 5 is actually pushed by the earth electrode, the valve 5 does not separate from the seat 4. When the entire valve 5 is deformed in the (+) direction in this manner, the valve opening step deviates from the standard toward the side with a large number of steps, and the EGR valve 1 may not open in a predetermined step. Then, when the valve opening step deviates from the predetermined standard as described above, there is a possibility that the EGR valve 1 can not be adjusted to flow the EGR gas of the required flow rate.

  On the other hand, as shown in FIG. 3, in the product of the present embodiment, the position of the shaft 6 after welding falls within the target position. In addition, even if the welding energy is changed within the non-defective range α (within the range where non-defective items can be manufactured) assumed at the time of manufacturing the EGR valve 1 shown in FIG. . As shown in FIG. 4, in the product of the present embodiment, the position of the shaft 6 after welding remains at the target position even if the welding energy is changed outside the non-defective product range α.

  As described above, in the product of this embodiment, since the plate thickness Tv is large and the ratio R1 of the plate thickness / shaft diameter is large, the valve immediately after welding is compared with the comparative product shown in FIG. The amount of deformation in the (−) direction of 5 is small, and the amount of return in the (+) direction of the valve 5 when the weld is solidified also becomes small. Therefore, as a result, the position of the shaft 6 after welding remains within the target position in the (−) direction rather than the position “0” of the shaft 6 at the start of welding. Therefore, in the product of this embodiment, the opening step satisfies the predetermined standard, and the EGR valve 1 can be adjusted to flow the EGR gas of the required flow rate.

  And from the result of the evaluation shown in FIG. 3, when ratio R1 of plate thickness / shaft diameter is 0.55-0.66, it turned out that the position of the shaft 6 after welding remains at a target position.

  In this manner, in the present embodiment, the pressed valve 5 is welded to the shaft 6 as a measure for enlarging the diameter Dv (see FIG. 2) of the valve 5 for high flow rate and reducing the thickness of the valve 5. There is. Then, by setting the plate thickness Tv of the bottom portion 41 of the valve 5 in accordance with the size of the shaft diameter Ds, the amount of deformation of the valve 5 immediately after welding when welding the shaft 6 to the valve 5 is reduced. The change of the position 6 can be reduced, and the displacement of the shaft 6 after welding can be suppressed.

  The predetermined value when the ratio R1 of the plate thickness / shaft diameter is set to a predetermined value or more is determined depending on the material of the valve 5. Therefore, the predetermined value is changed according to the material of the valve 5. In the present embodiment, the material of the valve 5 is iron or a material containing iron (for example, stainless steel), and the predetermined value is set between 0.55 and 0.66, but the material of the valve 5 is another material (for example, In the case of non-ferrous metals such as aluminum), the predetermined value is changed according to the material.

  When the plate thickness Tv of the bottom portion 41 of the valve 5 is increased as described above, the position of the shaft 6 after welding can be accommodated at the target position. However, if the mass of the valve 5 is increased by increasing the plate thickness Tv, the valve 5 may resonate and be removed from the shaft 6 by the vibration (for example, the vibration of the engine) applied to the EGR valve 1 Get higher.

  Therefore, in the present embodiment, the upper limit of the mass of the valve 5 is defined. Specifically, in the present embodiment, the mass of the valve 5 is set smaller than the predetermined mass. The predetermined mass is set to a value such that the frequency (vibration frequency) of the valve 5 when vibration is applied to the EGR valve 1 is higher than the upper limit of the resonance frequency band of the valve 5. Specifically, as shown in FIG. 6, the frequency of the valve 5 increases as the mass of the valve 5 decreases, and the mass of the valve 5 of the present embodiment is the vibration resistance deterioration region β of the valve 5 (valve The value is set to a value (e.g., 6.7 g to 7.4 g) that is higher than the upper limit frequency fmax (e.g., 270 Hz) of the resonance frequency band 5). As a result, when engine vibration is applied to the EGR valve 1, the valve 5 does not easily resonate. Therefore, it is possible to suppress the valve 5 from being taken out of the shaft 6 due to the vibration of the engine. In addition, the comparative product whose mass of the valve | bulb shown in FIG. 6 is 20 g or more is a valve of the existing shape which is not thinned in the shape of an umbrella.

  Further, in the present embodiment, the through hole 44 of the valve 5 is formed by punching and pressing. Here, if the thickness of the sheared surface 44a formed on the inner wall of the through hole 44 is small and the thickness of the fractured surface is large, the fractured surface of the valve 5 when the valve 5 and the shaft 6 are combined in welding. And the gap generated between the shaft 6 and the shaft 6 becomes large. Then, at the time of welding, the contact area between the valve 5 and the shaft 6 is reduced, and air enters the gap between the broken surface of the valve 5 and the shaft 6 to be thermally insulated. The heat becomes worse.

  Therefore, in the present embodiment, after punching the through hole 44, the through hole 44 is subjected to shaving processing, and the axial length L (see FIG. 2) of the through hole 44 with respect to the shearing surface 44a The length is set to a predetermined ratio or more with respect to Tv. And this predetermined ratio is taken as the value by which heat transfer from the shaft 6 to the bottom 41 of the valve 5 is made uniform when welding the valve 5 and the shaft 6. Specifically, the length L in the axial direction of the through hole 44 with respect to the shearing surface 44 a is set to 49% or more of the thickness Tv of the bottom portion 41 with the predetermined ratio being 49%.

  Here, the applicant evaluated the effect of setting the length L of the sheared surface 44a. As a result of evaluation, as shown in FIG. 7, a ratio R2 of shear surface length / plate thickness showing a ratio (ratio) of length L of shear surface 44a (to) to plate thickness Tv of bottom portion 41 in valve 5 is The shaft position after welding was out of the range of the target position in the comparison product of less than 49%. On the other hand, in this embodiment (R2 = 49.6%, 68.7%) in which the shear surface length / plate thickness ratio R2 is 49% or more, the shaft position after welding falls within the target position range. It settled.

  As described above, in the present embodiment, since the length L of the sheared surface 44 a is set to a predetermined ratio or more with respect to the plate thickness Tv of the bottom portion 41, the contact area of the valve 5 and the shaft 6 at the time of welding is The heat transfer property from the shaft 6 to the valve 5 is improved. Therefore, uniform heat conduction from the shaft 6 to the valve 5 at the time of welding, that is, since heat transfer from the shaft 6 to the valve 5 at the time of welding can be equalized in the direction of thickness Tv, deformation of the valve 5 at the time of welding Can be suppressed.

  Further, by setting the ratio of the valve diameter Dv (diameter of the valve 5) to the plate thickness Tv of the bottom portion 41 of the valve 5 to a predetermined value (for example, 8.0 to 9.0), the valve diameter Dv of the valve 5 is obtained. While maintaining a weight that can withstand vibrations (e.g. engine vibrations). And thereby, position shift of shaft 6 after welding can be controlled further.

  As mentioned above, in this embodiment, ratio R1 of board thickness / shaft diameter is set more than predetermined ratio, and this predetermined ratio is determined depending on the material of valve 5. In this manner, by securing the plate thickness Tv of the bottom portion 41 of the valve 5 at least a predetermined ratio to the shaft diameter Ds, the amount of deformation of the valve 5 generated when welding the valve 5 and the shaft 6 can be obtained. It can be kept small. Therefore, positional deviation of the shaft 6 welded to the valve 5 can be suppressed. Here, the predetermined ratio is a value at which the position of the shaft 6 after welding falls within the target position as the amount of deformation of the valve 5 immediately after welding becomes smaller and the amount of return of the valve 5 becomes smaller when the welded portion solidifies. I assume. Since the predetermined ratio is determined depending on the material of the valve 5, by setting the thickness Tv of the bottom portion 41 of the valve 5 according to the material of the valve 5, the shaft 6 of the shaft 6 is selected regardless of the material of the valve 5. Misalignment can be suppressed.

  The material of the valve 5 is iron or a material containing iron, and the predetermined ratio is set between 0.55 and 0.65. Thereby, a plate thickness Tv having a sufficient size with respect to the shaft diameter Ds can be secured, so the amount of deformation of the valve 5 in the (-) direction immediately after welding is reduced, and the valve 5 is solidified The amount of return in the (+) direction of can be reduced. And thereby, the position of the shaft 6 after welding can be stored in a target position. Therefore, positional deviation of the shaft 6 welded to the valve 5 can be suppressed more reliably.

  Further, in the present embodiment, the mass of the valve 5 is smaller than the predetermined mass. The predetermined mass is set to a value such that the frequency of the valve 5 when vibration is applied to the EGR valve 1 is higher than the upper limit value of the resonance frequency band of the valve 5. By setting the upper limit of the mass of the valve 5 in this manner, it is possible to suppress the valve 5 from being removed from the shaft 6 by vibration (for example, vibration of the engine).

  Further, in the present embodiment, the through hole 44 of the valve 5 is formed by press processing. The axial length L of the through hole 44 with respect to the sheared surface 44 a formed on the inner wall of the through hole 44 is a predetermined ratio or more with respect to the thickness Tv of the bottom portion 41 of the valve 5. And this predetermined ratio is a value which can equalize the heat transfer from the shaft 6 to the valve 5 when welding the bottom 41 of the valve 5 and the shaft 6. Thereby, the heat conduction to the valve 5 at the time of welding can be made uniform, so that the deformation of the valve 5 at the time of welding can be suppressed.

  And by making the said predetermined ratio into 49%, since equalization | homogenization of the heat conduction with respect to the valve | bulb 5 at the time of welding can be achieved more reliably, a deformation | transformation of the valve | bulb 5 at the time of welding can be suppressed.

  Further, the plate thickness Tw (see FIG. 2) of the side wall portion 42 does not contribute to the suppression of the positional deviation of the shaft 6, and therefore, can be smaller than the plate thickness Tv of the bottom portion 41. Thereby, the weight of the valve 5 can be reduced.

  The embodiment described above is merely an example, and does not limit the present disclosure in any way, and it goes without saying that various improvements and modifications can be made without departing from the scope of the invention.

  For example, the shape of the valve 5 is not limited to the umbrella shape, and may be a cubic shape in which one end face is open. Moreover, the mass of the valve 5 may be set to the above-mentioned predetermined mass or more. Further, the mass of the valve 5 may be set to a value such that the frequency of the valve 5 when vibration is applied to the EGR valve 1 is lower than the seismic resistance deterioration region β. Further, the material of the valve 5 and the shaft 6 is not limited to the material containing iron or iron, and may be, for example, aluminum or brass. In addition, welding of the valve 5 and the shaft 6 may be performed by welding (for example, arc welding) other than TIG welding.

  When the length L of the sheared surface 44 a of the through hole 44 of the valve 5 is set to a length greater than or equal to a predetermined ratio with respect to the plate thickness Tv of the bottom portion 41, the ratio R2 of sheared surface length / plate thickness The ratio may be set to a value larger than 49%. Alternatively, the shear surface length / plate thickness ratio R2 may not necessarily be taken into account.

  Further, the thickness Tw of the side wall portion 42 may be set equal to or greater than the thickness Tv of the bottom portion 41.

  Further, the through hole 44 of the valve 5 may be formed by cutting in addition to being formed by pressing.

  Moreover, if it is what employ | adopts a poppet valve, not only an EGR valve but any thing can apply the valve | bulb of this application, for example, the flow volume switching valve employ | adopted as an air conditioner is the example.

1 EGR valve 4 seat 5 valve 6 shaft 7 output shaft 7a male screw 8 step motor 23 magnet rotor 27 rotor main body 27a female screw 28 plastic magnet 41 bottom 42 side wall 43 opening 44 through hole 44a shear plane 51 tip Tv thickness Tw Plate thickness Ds Shaft diameter Dv Valve diameter R1 Plate thickness / shaft diameter ratio R2 Shear surface length / plate thickness ratio α Good range β Seismic resistance deterioration area fmax Upper limit frequency L Length

Claims (7)

With a valve seat,
A valve element which is in contact with and separated from the valve seat and includes a bottom and a side wall provided to rise from the edge of the bottom, the side facing the bottom being open; ,
A shaft inserted into the through hole of the bottom of the valve body and welded to the bottom;
A stepper motor for driving the shaft portion in the axial direction of the shaft portion;
The ratio of the plate thickness of the bottom portion of the valve body to the diameter of the shaft portion is set to a predetermined ratio or more,
The predetermined ratio is determined depending on the material of the valve body.
Poppet valve characterized by. In the poppet valve of claim 1,
The material of the valve body is a material containing iron or iron,
The predetermined ratio is set between 0.55 and 0.65,
Poppet valve characterized by. In the poppet valve of claim 1 or 2,
The mass of the valve body is smaller than a predetermined mass,
The predetermined mass is set to a value such that the frequency of the valve body when vibration is applied to the poppet valve is higher than the upper limit value of the resonance frequency band.
Poppet valve characterized by. The poppet valve according to any one of claims 1 to 3
The through holes are formed by punching and pressing.
The axial length of the through hole with respect to the shear plane formed on the inner wall of the through hole is a length that is a predetermined ratio or more with respect to the thickness of the bottom portion,
The predetermined ratio is a value that can equalize the heat transfer from the shaft to the bottom when the bottom of the valve body and the shaft are welded.
Poppet valve characterized by. In the poppet valve of claim 4,
The predetermined ratio is 49%.
Poppet valve characterized by. The poppet valve according to any one of claims 1 to 5,
The thickness of the side wall portion is smaller than the thickness of the bottom portion,
Poppet valve characterized by. The poppet valve according to any one of claims 1 to 6,
The poppet valve is an EGR valve that regulates the flow rate of EGR gas flowing from the exhaust passage of the engine to the intake passage,
Poppet valve characterized by.

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