JP6692446B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve that supplies fuel to an internal combustion engine of an automobile, for example.

  Conventionally, a valve member is housed in a cylindrical housing so as to be capable of reciprocating, and the nozzle hole is closed by bringing the valve member into contact with the valve seat, and the nozzle hole is opened by moving the valve member away from the valve seat. Injectors are known. A movable core that moves integrally with the valve member is accommodated in the housing. A fixed core arranged upstream of the movable core is fixed to the housing. A coil portion that generates an electromagnetic attraction force that attracts the movable core to the fixed core is provided around the housing. When the energization of the coil portion is stopped, the force of the spring causes the valve member to contact the valve seat. When the coil is energized, the electromagnetic attraction of the coil causes the valve member to move away from the valve seat against the force of the spring.

  Conventionally, in order to reduce the operating noise when the movable core collides with the fixed core at the time of valve opening, the gap between the inner peripheral surface of the housing and the outer peripheral surface of the movable core is adjusted, and the fixed core of the movable core is adjusted. There has been proposed a fuel injection device in which an annular protrusion is provided at the side end. In such a conventional fuel injection device, the space existing between the movable core and the fixed core becomes larger on the outer side in the radial direction of the projecting portion, and the fuel flowing through the gap between the inner peripheral surface of the housing and the outer peripheral surface of the movable core. The fluid damper effect due to the resistance of is increased. As a result, the speed of the movable core at the time of opening the valve is reduced, and the operating noise at the time of opening the valve is reduced (see Patent Document 1, for example).

JP, 2003-148280, A

  However, in the conventional fuel injection device shown in Patent Document 1, since the protrusion has the flat surface, when the valve closing operation for closing the injection hole is started, that is, the movement in the direction away from the fixed core is performed. When the movable core starts, the fluid sticking force that hinders the separation between the movable core and the fixed core, that is, the squeeze force becomes large, and the responsiveness at the time of valve closing deteriorates.

  Further, in the conventional fuel injection device shown in Patent Document 1, since the protrusion has a flat surface, if the movable core tilts when the movable core collides with the fixed core, the protrusion of The outer peripheral corners of the flat surface contact the fixed core. On the other hand, when the movable core is not tilted when the movable core collides with the fixed core, the flat surface of the protrusion partially contacts the fixed core depending on the finish of the flat surface of the protrusion. .. Therefore, in the conventional fuel injection device, the position at which the protrusion contacts the fixed core differs for each individual fuel injection device and for each operation, resulting in variations in operating noise during valve opening.

  The present invention has been made to solve the above problems, and can suppress the occurrence of variations in operating noise during valve opening and suppress the deterioration of responsiveness during valve closing. The purpose is to obtain a fuel injection valve capable of

  A fuel injection valve according to the present invention has a tubular core, a seat surface is formed, a valve seat arranged downstream of the core in the flow of fuel, and a displaceable arrangement between the core and the seat surface, A valve body that closes the fuel passage when it contacts the seat surface and opens the fuel passage when it separates from the seat surface, a cylindrical holder that houses the valve seat and the valve body, and urges the valve body in the direction that contacts the seat surface. It is equipped with a spring and a coil that generates an electromagnetic attraction force that displaces the valve body in the direction away from the seat surface against the biasing force of the spring.The valve body is fixed to the armature and the cylindrical armature facing the core. The valve body is in contact with the seat surface by the displacement of the armature in the direction away from the core, and is separated from the seat surface by the displacement of the amateur in the direction toward the core. The end portion on the core side of is provided with a convex portion and a flat surface forming portion located radially outward of the convex portion, and the flat surface forming portion includes a first orthogonal flat surface portion continuous from the convex portion. And the first orthogonal plane portion is parallel to a plane orthogonal to the amateur's axis, and the convex portion projects toward the core more than the position of the first orthogonal plane portion, and the amateur's axis line The outline of the convex portion on a plane including is an arc-shaped curve continuous from the inner peripheral surface of the amateur.

  According to the fuel injection valve of the present invention, the contact area between the convex portion of the amateur and the core can be reduced, and the squeeze force acting between the amateur and the core when the amateur is closed from the core is reduced. Can be made Therefore, it is possible to easily displace the valve body toward the seat surface, and it is possible to suppress deterioration of responsiveness when the fuel injection valve is closed. Further, it is possible to reduce the variation in the contact state between the core and the convex portion regardless of the inclination of the amateur, and it is possible to suppress the variation in the operating noise when the valve is opened.

FIG. 3 is a sectional view showing a fuel injection valve according to Embodiment 1 of the present invention. It is an expanded sectional view which shows the amateur of FIG. It is a top view which shows the amateur of FIG. FIG. 9 is an enlarged cross-sectional view of an essential part showing an armature and a core of a fuel injection valve according to Embodiment 2 of the present invention. FIG. 9 is an enlarged cross-sectional view of an essential part showing an armature and a core of a fuel injection valve according to Embodiment 3 of the present invention. FIG. 11 is a sectional view showing an amateur of a fuel injection valve according to Embodiment 4 of the present invention. It is a top view which shows the amateur of FIG. FIG. 11 is a sectional view showing an amateur of a fuel injection valve according to Embodiment 5 of the present invention. It is a top view which shows the amateur of FIG. FIG. 13 is an enlarged sectional view of an essential part showing an armature and a core of a fuel injection valve according to Embodiment 6 of the present invention. FIG. 13 is an enlarged sectional view of an essential part showing an armature and a core of a fuel injection valve according to Embodiment 6 of the present invention. It is a top view which shows the amateur of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1.
1 is a sectional view showing a fuel injection valve according to Embodiment 1 of the present invention. The fuel injection valve 1 has a drive device 2 and a valve device 3 operated by the drive device 2. The fuel is injected from the valve device 3 after passing through the respective fuel passages in the drive device 2 and the valve device 3.

  The drive device 2 is arranged inside the housing 4 in a state in which the housing 4 is made of a metal having a two-stage cylindrical shape, a cylindrical core 5 made of metal is arranged inside the housing 4, and the core 5 is surrounded. The coil 6, the bobbin 7 made of resin around which the coil 6 is wound, and a metal cap 8 fixed to a part of the outer peripheral portion of the housing 4 by welding and covering the bobbin 7 around the core 5. And a terminal 9 for electrically connecting the coil 6 to the outside. The housing 4, the core 5, the coil 6, the bobbin 7, the cap 8 and the terminal 9 are integrated by a molded body 10 made of resin. Further, the housing 4, the core 5, the coil 6, the bobbin 7, and the cap 8 are arranged coaxially with the axis A of the fuel injection valve 1.

  The cap 8 is provided with a cutout portion. The terminal 9 is connected to the coil 6 through the cutout portion of the cap 8. When the coil 6 is energized through the terminal 9, an electromagnetic force is generated from the coil 6.

  The valve device 3 includes a valve seat 12 in which a valve seat inner space portion 11 is provided, a nozzle hole plate 13 arranged downstream of the valve seat 12 in the flow of fuel, and a direction along an axis A. A valve body 14 that is displaceable with respect to the valve seat 12, a cylindrical holder 15 that houses the valve seat 12, the injection hole plate 13, and the valve body 14, and is arranged upstream of the valve body 14 in the fuel flow. It has a cylindrical fixed rod 16 fixed to the core 5 and a spring 17 which is an elastic body arranged between the valve element 14 and the fixed rod 16.

  The holder 15 is fixed to the housing 4. The valve seat 12 is fixed to the inner peripheral surface of the holder 15. The injection hole plate 13 is fixed to the valve seat 12. The valve seat 12, the injection hole plate 13, the valve element 14, the holder 15, the fixed rod 16 and the spring 17 are arranged coaxially with the axis A of the fuel injection valve 1.

  The valve seat 12 is arranged downstream of the core 5 in the fuel flow. The valve seat 12 is provided with a through hole 12a that penetrates from the valve seat inner space 11 toward the injection hole plate 13 as a fuel passage. The through hole 12a is provided coaxially with the axis A. The inner surface of the valve seat inner space portion 11 continuously has a cylindrical sliding surface 18 along the direction in which the valve element 14 is displaced and a direction from the sliding surface 18 toward the through hole 12a toward the axis A. And an inclined conical seat surface 19. That is, on the inner peripheral portion of the valve seat 12, a sliding surface 18 along the axis A and a seat surface 19 inclined with respect to the axis A are formed.

  The valve element 14 is arranged so as to be displaceable between the core 5 and the seat surface 19. Further, the valve body 14 has a cylindrical armature 21 which is a movable iron core arranged in the holder 15, and a valve body 22 fixed to the armature 21. The valve body 22 has a ball 23 inserted in the valve seat inner space 11, and a tubular connecting member 24 that connects the armature 21 and the ball 23. The valve body 14 is displaced with respect to the valve seat 12 while guiding the ball 23 to the sliding surface 18.

  The armature 21 faces the core 5 in the direction along the axis A of the fuel injection valve 1. A fuel passage through which fuel flows is formed between the inner surface of the valve seat inner space portion 11 and the ball 23. When the valve body 14 is displaced with respect to the valve seat 12, the ball 23 of the valve body 22 contacts the seat surface 19 or separates from the seat surface 19. The ball 23 of the valve body 22 contacts the seat surface 19 by the displacement of the armature 21 in the direction away from the core 5, and leaves the seat surface 19 by the displacement of the armature 21 in the direction toward the core 5.

  When the ball 23 separates from the seat surface 19, a gap is created between the ball 23 and the seat surface 19 as a fuel passage, and the fuel passage is opened, that is, the valve is opened. When the ball 23 comes into contact with the seat surface 19, the gap between the ball 23 and the seat surface 19 disappears, and the fuel passage is closed, that is, the valve is closed.

  The fuel flows through the fuel passage formed between the inner surface of the valve seat inner space portion 11 and the ball 23 in the order of the sliding surface 18 and the seat surface 19, and then passes through the through hole 12a to the injection hole plate 13. .. The amount of fuel flowing out from the through hole 12a to the injection hole plate 13 is adjusted by the ball 23 coming into contact with the seat surface 19 or the ball 23 moving away from the seat surface 19.

  At the end of the core 5 on the side of the armature 21, a core downstream side end surface 25 facing the armature 21 is formed. In this example, the core downstream end surface 25 is orthogonal to the axis A of the fuel injection valve 1. When the fuel injection valve 1 is opened, the armature 21 contacts the core downstream end surface 25 of the core 5.

  The injection hole plate 13 is fixed to the valve seat 12 by welding. The injection hole plate 13 is provided with a plurality of fuel injection holes 26 penetrating the injection hole plate 13. The fuel discharged from the through hole 12a of the valve seat 12 to the injection hole plate 13 is injected from the plurality of fuel injection holes 26 to the outside.

  The spring 17 generates an elastic restoring force in a state of being compressed between the fixed rod 16 and the connecting member 24. As a result, the spring 17 biases the valve body 14 in the direction in which the ball 23 contacts the seat surface 19.

  When the electromagnetic force of the coil 6 is generated, the armature 21 is attracted to the core 5. That is, the coil 6 generates an electromagnetic attraction force that attracts the armature 21 to the core 5. When the electromagnetic attraction force of the coil 6 is generated, the valve body 14 is displaced in the direction away from the seat surface 19 against the biasing force of the spring 17.

  The space in the fixed rod 16, the space in which the spring 17 is arranged, and the space in the connecting member 24 are fuel passages through which fuel flows. After flowing through the fuel passage in the order of the fixed rod 16, the spring 17, and the connecting member 24, the fuel flows into the valve seat inner space portion 11 of the valve seat 12.

  FIG. 2 is an enlarged sectional view showing the amateur 21 of FIG. FIG. 3 is a top view showing the amateur 21 of FIG. At the end of the armature 21 on the core 5 side, a convex portion 31 and a plane forming portion 32 located radially outside the convex portion 31 are provided.

  As shown in FIG. 3, the shape of the convex portion 31 when viewed along the axis B of the armature 21 is an annular shape along the circumferential direction of the armature 21. In this example, the convex portion 31 is arranged on a circle centered on the axis B of the amateur 21. The convex portion 31 is provided on the inner peripheral portion of the end portion of the amateur 21 on the core 5 side. Further, the outline of the convex portion 31 when the amateur 21 is cut along a plane including the axis B of the armature 21 is an arc-shaped curve which is continuous from the inner peripheral surface of the armature 21 and rises toward the core 5 side. In this example, as shown in FIG. 2, the outline of the convex portion 31 when the armature 21 is cut along a plane including the axis B of the armature 21 has an arc shape having a radius r.

  The flat surface forming portion 32 has a first orthogonal flat surface portion 33 continuous from the convex portion 31 to the outside in the radial direction. The first orthogonal flat surface portion 33 is formed over the entire circumference of the armature 21 radially outside the convex portion 31. Further, the first orthogonal flat surface portion 33 is parallel to a flat surface orthogonal to the axis B of the armature 21. The convex portion 31 projects from the position of the first orthogonal flat surface portion 33 toward the core 5 in the direction along the axis B of the amateur 21.

  As shown in FIG. 1, the armature 21 is displaced in the direction along the axis A of the fuel injection valve 1 while being guided by the holder 15. A gap s exists between the outer peripheral surface of the armature 21 and the inner peripheral surface of the holder 15. As a result, the armature 21 may come into contact with the core downstream end surface 25 in a state of being inclined with respect to the axis A of the fuel injection valve 1.

  The height of the convex portion 31 from the position of the first orthogonal flat surface portion 33 is set based on the maximum inclination of the amateur 21 with respect to the axis A. As a result, even when the armature 21 contacts the core downstream side end surface 25 in a state of being inclined with respect to the axis A, other parts of the amateur 21 other than the convex portion 31 are kept apart from the core downstream side end surface 25. As it is, only the convex portion 31 contacts the core downstream end surface 25. Further, since the outline of the convex portion 31 when the armature 21 is cut along a plane including the axis B of the armature 21 is an arc-shaped curve, when the fuel injection valve 1 is in the open state, The portion 31 contacts the core downstream end surface 25 in a line contact state.

  Next, the operation will be described. In a state where the coil 6 is de-energized, the ball 23 of the valve body 22 is in contact with the seat surface 19 of the valve seat 12 by the biasing force of the spring 17. As a result, the fuel passage is closed and the supply of fuel from the valve seat 12 to the injection hole plate 13 is stopped.

  When the coil 6 is energized, an electromagnetic attractive force is generated, and the armature 21 is attracted to the core 5. As a result, the valve body 14 is displaced toward the core 5 against the biasing force of the spring 17. As a result, the ball 23 of the valve body 22 separates from the seat surface 19 of the valve seat 12, and the valve is opened with the fuel passage open.

  When the fuel injection valve 1 is opened, the armature 21 contacts the core downstream end surface 25 of the core 5. At this time, only the convex portion 31 comes into contact with the core downstream side end surface 25 while the other portions of the amateur 21 other than the convex portion 31 are kept apart from the core downstream side end surface 25. Since the outline of the convex portion 31 is an arc-shaped curve, the convex portion 31 contacts the core downstream side end surface 25 in a line contact state.

  In the valve open state, the fuel flowing from the fuel passage in the connecting member 24 into the valve seat inner space 11 reaches the seat surface 19 through the fuel passage formed between the ball 23 and the sliding surface 18. After that, it flows into the through hole 12a through the fuel passage formed between the ball 23 and the seat surface 19. After that, the fuel flows from the through hole 12a to the injection hole plate 13, and is injected to the outside through the plurality of fuel injection holes 26.

  On the other hand, when the energization of the coil 6 is stopped, the electromagnetic attraction force disappears, and the urging force of the spring 17 displaces the valve element 14 in the direction toward the seat surface 19 of the valve seat 12. Then, the ball 23 of the valve body 22 comes into contact with the seat surface 19 and the fuel passage is closed. As a result, the fuel supply from the through hole 12a of the valve seat 12 to the injection hole plate 13 is stopped.

  In such a fuel injection valve 1, the convex portion 31 and the first orthogonal flat surface portion 33 continuous from the convex portion 31 are provided at the end of the armature 21 on the core 5 side, and the axis B of the amateur 21 is Since the outline of the convex portion 31 on the plane including the curved surface is an arc-shaped curve continuous from the inner peripheral surface of the amateur 21, when the convex portion 31 of the amateur 21 comes into contact with the core 5, the convex portion 31 and the core 5 It is possible to make the contact state with the line contact state. As a result, the contact area between the armature 21 and the core 5 can be reduced, and the squeeze force that acts between the armature 21 and the core 5 when the armature 21 is closed from the core 5 can be reduced. .. Therefore, the valve body 14 can be easily displaced toward the seat surface 19, and deterioration of responsiveness when the fuel injection valve 1 is closed can be suppressed. Further, since the convex portion 31 is provided, the volume of the space existing between the core downstream side end surface 25 and the plane forming portion 32 on the radial outer side of the convex portion 31 can be increased, and the core downstream side can be increased. The fluid damper effect due to the fuel existing between the end surface 25 and the plane forming portion 32 can be increased. As a result, the resistance force to the displacement of the valve body 14 in the direction approaching the core 5 can be increased, and the speed of the valve body 14 at the time of opening the valve can be reduced. Therefore, it is possible to reduce the operating noise when the valve is opened.

  Further, when the fuel injection valve 1 is opened, the armature 21 may contact the core 5 in a state where the armature 21 is inclined with respect to the axis A of the fuel injection valve 1. The degree of inclination of the amateur 21 when coming into contact with the core 5 differs depending on the individual fuel injection valve 1. Further, when the convex portion 31 of the amateur 21 is provided with a flat surface, the finish of the flat surface of the convex portion also differs for each individual fuel injection valve 1. Therefore, when the convex portion 31 of the armature 21 is provided with a flat surface, the variation in the operating noise at the time of valve opening when the armature 21 collides with the core 5 becomes large for each individual fuel injection valve 1. That is, when a flat surface is provided on the convex portion 31 of the amateur 21, if the inclination of the amateur 21 becomes large, the amateur 21 comes into contact with the core 5 at the outermost peripheral portion of the flat surface of the convex portion, and the inclination of the amateur 21 is small. When the core downstream end surface 25 of the core 5 and the flat surface of the convex portion of the amateur 21 become substantially parallel, the contact position is changed depending on the flatness of the flatness of the core downstream end surface 25 of the core 5 and the flat surface of the convex portion. Because of the variation, the variation in the operating noise generated when the armature 21 collides with the core 5 becomes large for each individual fuel injection valve 1.

  On the other hand, in the present embodiment, the outline of the convex portion 31 on the plane including the axis B of the armature 21 is an arc-shaped curve continuous from the inner peripheral surface of the armature 21, so that the fuel injection valve No matter how the armature 21 is inclined with respect to the axis A of 1, the variation in the contact state between the core downstream end surface 25 and the convex portion 31 becomes small. As a result, it is possible to reduce variations in operating noise when the valve is opened.

  Furthermore, in the case where the convex portion 31 of the amateur 21 is provided with a flat surface, when the amateur 21 tilts, the outermost peripheral portion of the flat surface of the convex portion 31 contacts the core downstream end surface 25 of the core 5. On the other hand, in the present embodiment, since the outline of the armature 21 is an arc-shaped curve, the convex portion 31 is located at a position radially inward of the core 5 with respect to the outermost peripheral portion of the flat surface of the convex portion 31. Contacts the core 5. As a result, the transmission path from the contact position of the convex portion 31 to the core 5 to the vibration reaching the outer peripheral surface of the core 5 is an arc-shaped curve of the outline of the convex portion 31 as compared with the case where the convex portion 31 has a flat surface. The length of the present embodiment, which is Therefore, by making the outline of the convex portion 31 on a plane including the axis B of the amateur 21 into an arc-shaped curve, it is possible to increase the damping of the vibration in the core 5 and to more reliably generate the operating noise during valve opening. Can be suppressed.

  Further, since the protrusions 31 are arranged in an annular shape along the circumferential direction of the armature 21, only the protrusions 31 of the armature 21 can be brought into contact with the core downstream end surface 25 more reliably. As a result, it is possible to further surely reduce the variation in the operating noise when the valve is opened.

Embodiment 2.
FIG. 4 is an enlarged sectional view of an essential part showing an armature 21 and a core 5 of a fuel injection valve according to Embodiment 2 of the present invention. The flat surface forming portion 32 has a first orthogonal flat surface portion 33 that is continuous from the convex portion 31 and a second orthogonal flat surface portion 34 that is located radially outward of the first orthogonal flat surface portion 33. The second orthogonal flat surface portion 34 is formed radially outside of the first orthogonal flat surface portion 33 over the entire circumference of the armature 21. The first orthogonal plane portion 33 and the second orthogonal plane portion 34 are parallel to the plane orthogonal to the axis B of the armature 21.

  The position of the second orthogonal flat surface portion 34 is farther from the core downstream end face 25 than the position of the first orthogonal flat surface portion 33. That is, the second gap g2, which is the distance between the second orthogonal flat surface portion 34 and the core downstream end surface 25, is the distance between the first orthogonal flat surface portion 33 and the core downstream end surface 25. It is larger than the gap g1 of 1. Therefore, in the space E existing radially outside the convex portion 31, the distance between the flat surface forming portion 32 and the core downstream side end surface 25 is equal to that of the first orthogonal flat surface portion 33 and the second orthogonal flat surface portion 34. In order, it gradually expands outward in the radial direction of the amateur 21. Other configurations and operations are similar to those of the first embodiment.

  In such a fuel injection valve 1, the second gap g2, which is the distance between the second orthogonal flat surface portion 34 and the core downstream side end surface 25, is different from the first orthogonal flat surface portion 33 and the core downstream side end surface 25. Since the distance is larger than the first gap g1 which is the distance between the two, even when the armature 21 is inclined with respect to the axis A of the fuel injection valve 1 and the convex portion 31 comes into contact with the core downstream side end surface 25. By the existence of the second gap g2, it is possible to make it difficult for other portions of the amateur 21 other than the convex portion 31 to come into contact with the core downstream side end surface 25. In addition, since the portion closer to the convex portion 31 in the plane forming portion 32 is less likely to contact the core downstream side end surface 25, the position of the first orthogonal plane portion 33 can be brought closer to the core downstream side end surface 25, The first gap g1 that is the distance between the first orthogonal flat surface portion 33 and the core downstream end surface 25 can be reduced. As a result, the electromagnetic attraction force between the core 5 and the armature 21 can be increased, and the responsiveness when the fuel injection valve 1 is opened can be improved.

  In the above example, the number of orthogonal plane portions included in the plane forming portion 32 is two, that is, the first orthogonal plane portion 33 and the second orthogonal plane portion 34. The plane forming portion 32 may include three or more orthogonal plane portions that are parallel to the plane orthogonal to. In this case, the second orthogonal flat surface portion 34 is provided radially outside of the first orthogonal flat surface portion 33, and another orthogonal flat surface portion is provided radially outward of the second orthogonal flat surface portion 34. Further, in this case, each orthogonal flat surface portion of the flat surface forming portion 32 is formed so that the distance between the flat surface forming portion 32 and the core downstream side end surface 25 gradually increases toward the radially outer side of the amateur 21. It is formed at the end on the core 5 side.

Embodiment 3.
FIG. 5 is an enlarged sectional view of an essential part showing an armature 21 and a core 5 of a fuel injection valve according to Embodiment 3 of the present invention. At the end of the armature 21 on the core 5 side, an amateur side taper surface portion 41 located radially outward of the plane forming portion 32 is provided. The amateur side taper surface portion 41 is formed over the entire circumference of the armature 21 radially outside of the plane forming portion 32.

  The amateur side tapered surface portion 41 is inclined with respect to the axis B of the amateur 21. Further, the amateur side tapered surface portion 41 is inclined in a direction away from the core 5 from the flat surface forming portion 32 toward the radially outer side. In this example, only the first orthogonal flat surface portion 33 is included in the flat surface forming portion 32, and the amateur side tapered surface portion 41 is continuous from the first orthogonal flat surface portion 33 and extends radially outward from the core 5. It is tilted away. As a result, in the space E existing radially outside the convex portion 31, the distance between the armature-side taper surface portion 41 and the core downstream-side end surface 25 continuously expands radially outward of the armature 21. There is. Other configurations and operations are similar to those of the first embodiment.

  In such a fuel injection valve 1, since the amateur side taper surface portion 41 inclined in the direction away from the core 5 in the radial direction outward from the plane forming portion 32 is provided at the end of the armature 21 on the core 5 side. Even when the convex portion 31 comes into contact with the core downstream side end surface 25 in a state where the armature 21 is tilted with respect to the axis A of the fuel injection valve 1, other than the convex portion 31, the amateur 21 other than the convex portion 31 is contacted. It is possible to make it difficult for the portion to contact the core downstream side end surface 25. Further, the end of the armature 21 on the core 5 side close to the convex portion 31 can be brought closer to the core downstream end face 25, and the electromagnetic attraction force between the core 5 and the amateur 21 can be increased. .. Further, since the amateur side tapered surface portion 41 is continuously inclined, it is possible to eliminate the step in the amateur side tapered surface portion 41 and eliminate the loss of the electromagnetic attraction force at the step. As a result, the electromagnetic attraction force between the core 5 and the armature 21 can be further increased, and the response when the fuel injection valve 1 is opened can be further improved.

Fourth Embodiment
6 is a sectional view showing an armature 21 of a fuel injection valve according to Embodiment 4 of the present invention. FIG. 7 is a top view showing the amateur 21 of FIG. A plurality of concave portions 42 are provided on the convex portion 31 arranged in a ring shape in the circumferential direction of the armature 21. The plurality of concave portions 42 are provided in the convex portion 31 so as to be separated from each other in the circumferential direction of the amateur 21. As a result, the plurality of convex portions 31 divided by the concave portion 42 in the circumferential direction of the amateur 21 are provided at the end portion of the amateur 21 on the core 5 side. That is, at the end of the armature 21 on the core 5 side, a plurality of protrusions 31 are provided at intervals in the circumferential direction of the armature 21 via the recesses 42. In this example, the six concave portions 42 are provided in the convex portion 31, and the six convex portions 31 divided by the concave portion 42 are provided in the end portion of the armature 21 on the core 5 side.

  The bottom surface 43 of each recess 42 is continuous with the first orthogonal flat surface portion 33. The bottom surface 43 of each recess 42 is also continuous with the inner peripheral surface of the amateur 21. Further, the bottom surface 43 of each recess 42 is parallel to the plane orthogonal to the axis B of the armature 21. That is, the bottom surface 43 of each recess 42 is on the same plane as the first orthogonal flat surface portion 33. Other configurations are similar to those of the first embodiment.

  In such a fuel injection valve 1, since the convex portion 31 is provided with the concave portion 42, the contact area of the armature 21 with respect to the core 5 can be further reduced by the concave portion 42. As a result, the squeeze force acting between the core 5 and the armature 21 when the valve is closed can be further reduced, and the responsiveness when the valve is closed can be further improved. Further, since the bottom surface 43 of the recess 42 is continuous with the first orthogonal flat surface portion 33 and is parallel to the plane orthogonal to the axis B of the armature 21, the bottom surface 43 of the recess portion 42 is formed into the first orthogonal flat surface portion. It can be arranged on the same plane as 33 and the bottom surface 43 of the recess 42 can be brought close to the core downstream end surface 25. As a result, it is possible to suppress a decrease in the electromagnetic attraction force between the core 5 and the armature 21.

  In addition, since a plurality of protrusions 31 are arranged at intervals in the circumferential direction of the armature 21 at the end of the armature 21 on the core 5 side, they act between the core 5 and the armature 21 when the valve is closed. The squeeze force to be applied can be further reduced, and the responsiveness when the valve is closed can be further improved.

  In the above example, the plurality of concave portions 42 are provided in the convex portion 31, but the present invention is not limited to this, and only one concave portion 42 may be provided in the convex portion 31. Even in this case, the contact area of the armature 21 with the core 5 can be reduced, and the responsiveness when the valve is closed can be improved.

  In addition, in the above example, the bottom surface 43 of the recess 42 is on the same plane as the first orthogonal flat surface portion 33, but the bottom surface 43 of the recess 42 is located downstream of the position of the first orthogonal flat surface portion 33 in the core. It may be formed at a position close to the side end surface 25. By doing so, it is possible to further suppress the reduction of the electromagnetic attraction force between the core 5 and the armature 21.

Embodiment 5.
8 is a sectional view showing an armature 21 of a fuel injection valve according to Embodiment 5 of the present invention. 9 is a top view showing the amateur 21 of FIG. At the end of the armature 21 on the core 5 side, a plurality of protrusions 31 are arranged at intervals in the circumferential direction of the armature 21. The shape of the outer surface of each of the plurality of convex portions 31 is the shape of a spherical portion. In this example, the plurality of protrusions 31 are arranged on a circle centered on the axis B of the amateur 21, and the outer surfaces of the plurality of protrusions 31 have the same shape. Other configurations are the same as those in the fourth embodiment.

  In such a fuel injection valve 1, the plurality of convex portions 31 are arranged at intervals in the circumferential direction of the armature 21, and the shape of the outer surface of each of the plurality of convex portions 31 is the shape of a spherical portion. Therefore, the contact state of the armature 21 with the end surface 25 on the downstream side of the core can be changed to the point contact state. As a result, the contact area between the core downstream end surface 25 and the armature 21 can be further reduced, and the squeeze force acting between the core 5 and the armature 21 when the valve is closed can be further reduced. Therefore, it is possible to further improve the responsiveness when the valve is closed.

Sixth embodiment.
FIG. 10 is an enlarged sectional view of an essential part showing an armature 21 and a core 5 of a fuel injection valve according to Embodiment 6 of the present invention. The core downstream side end surface 25 formed at the end of the core 5 on the side of the amateur 21 has an annular core side orthogonal flat surface portion 52 surrounding the axis A of the core 5 and a radial inner side of the core side orthogonal flat surface portion 52. It has the conical core side taper surface part 51 located.

  The core-side orthogonal plane portion 52 is parallel to the plane orthogonal to the axis A of the core 5. The core side tapered surface portion 51 is inclined with respect to the axis A of the core 5. Further, the core-side tapered surface portion 51 is inclined from the core-side orthogonal flat surface portion 52 toward the radially inner side of the core 5 in a direction away from the armature 21. As a result, at the end of the armature 21 of the core 5, a recessed portion that is recessed toward the axis A of the core 5 is formed by the core-side tapered surface portion 51. The convex portion 31 faces the core-side tapered surface portion 51 in the direction along the axis A of the core 5.

  When the armature 21 is attracted by the core 5 with the axis B of the armature 21 eccentric to the axis A of the core 5 when the valve is opened, the armature 21 is inclined with respect to the axis A of the core 5 and the convex portion 31 contacts the point P of the core side taper surface part 51 of FIG. When the convex portion 31 contacts the point P of the core side tapered surface portion 51, the convex portion 31 slides along the core side tapered surface portion 51 in the direction of arrow d in FIG. 10, that is, the axis B of the armature 21 is the axis A of the core 5. Is displaced toward the centering direction, and finally the convex portion 31 contacts the core side tapered surface portion 51 over the entire circumference of the core 5. Other configurations and operations are similar to those of the first embodiment.

  In such a fuel injection valve 1, the core side taper surface portion 51 that inclines toward the radial inner side of the core 5 in the direction away from the armature 21 is provided at the end of the core 5 on the armature 21 side, and the convex portion 31 is the core. Since the armature 21 faces the side taper surface portion 51, even if the armature 21 comes into contact with the core 5 in a state where the axis B of the armature 21 is eccentric with respect to the axis A of the core 5, the convex portion 31 has the core side taper surface portion 51. The armature 21 can be automatically displaced with respect to the core 5 in the direction of reducing the eccentricity between the axis B of the armature 21 and the axis A of the core 5 by being guided by the armature 21. Further, when the core downstream end surface 25 is a plane orthogonal to the axis A of the core 5, if the convex portion 31 collides with the core downstream end surface 25 when the valve is opened, the armature 21 is likely to bounce with respect to the core 5. If the convex portion 31 collides with the core-side tapered surface portion 51 when the valve is opened, the convex portion 31 slides along the core-side tapered surface portion 51, so that the armature 21 is less likely to bounce with respect to the core 5. Therefore, by providing the core-side tapered surface portion 51 at the end of the core 5 on the amateur 21 side, it is possible to further improve the responsiveness when the valve is opened. Further, when the convex portion 31 slides along the core-side tapered surface portion 51, friction loss occurs between the convex portion 31 and the core-side tapered surface portion 51. Therefore, the energy transmitted from the armature 21 to the core 5 should be reduced. Therefore, it is possible to further reduce the operating noise when the valve is opened.

  In the above example, the core downstream end surface 25 has the core-side orthogonal flat surface portion 52 and the core-side tapered flat surface portion 51, but the core-side orthogonal flat surface portion 52 may be omitted.

Embodiment 7.
11 is an enlarged sectional view of an essential part showing an armature 21 and a core 5 of a fuel injection valve according to Embodiment 6 of the present invention. FIG. 12 is a top view showing the amateur 21 of FIG. A curved surface portion 53 that smoothly connects the convex portion 31 and the first orthogonal flat surface portion 33 is provided between the convex portion 31 and the first orthogonal flat surface portion 33. In this example, the radius R of the circular arc that is the curved surface portion 53 is larger than the radius r of the circular arc that is the outline of the convex portion 31 on the plane including the axis B of the armature 21. Other configurations and operations are similar to those of the sixth embodiment.

  In such a fuel injection valve 1, since the curved surface portion 53 that smoothly connects the convex portion 31 and the first orthogonal flat surface portion 33 is provided between the convex portion 31 and the first orthogonal flat surface portion 33, The stagnation of the fuel flow at the boundary between the convex portion 31 and the first orthogonal flat surface portion 33 can be suppressed by the curved surface portion 53. As a result, it is possible to suppress the decrease in the pressure in the space E due to the pressure loss in the stagnation portion of the fuel, and it is possible to suppress the decrease in the fluid damper effect when the valve is opened.

  In the above example, the curved surface portion 53 that smoothly connects the convex portion 31 and the first orthogonal flat surface portion 33 is applied to the amateur 21 of the sixth embodiment, but the convex portion 31 and the first orthogonal flat surface portion are not included. The curved surface portion 53 that smoothly connects the portion 33 may be applied to the amateur 21 of the first to fifth embodiments. Even with this,

  Further, in the second embodiment, a curved surface portion that smoothly connects the first orthogonal flat surface portion 33 and the second orthogonal flat surface portion 34 is provided between the first orthogonal flat surface portion 33 and the second orthogonal flat surface portion 34. It may be provided. Even in this case, the stagnation of the fuel flow at the boundary between the first orthogonal flat surface portion 33 and the second orthogonal flat surface portion 34 can be suppressed, and the pressure drop in the space E can be suppressed. .. Further, in the third embodiment, a curved surface portion that smoothly connects the flat surface forming portion 32 and the amateur side tapered surface portion 41 may be provided between the flat surface forming portion 32 and the amateur side tapered surface portion 41. It is possible to suppress the stagnation of the fuel flow at the boundary between the flat surface forming portion 32 and the amateur side tapered surface portion 41, and it is possible to suppress the pressure drop in the space E.

  Further, the same configuration as that of the second embodiment in which the flat surface forming portion 32 has a plurality of orthogonal flat surface portions may be applied to the amateur 21 of the third to seventh embodiments.

  Further, the amateur side tapered surface portion 41 similar to that of the third embodiment may be applied to the amateur 21 of the fourth to seventh embodiments.

  Further, the core-side tapered surface portion 51 similar to that of the sixth embodiment may be applied to the core 5 of the second to fifth embodiments.

  In the present invention, it is possible to freely combine the above-described embodiments and appropriately modify and omit the above-described embodiments within the scope of the invention.

  1 fuel injection valve, 5 cores, 6 coils, 12 valve seats, 14 valve bodies, 15 holders, 17 springs, 19 seat surfaces, 21 armatures, 22 valve body bodies, 31 convex portions, 32 plane forming portions, 33 first Orthogonal plane portion, 34 Second orthogonal plane portion, 41 Amateur side tapered surface portion, 42 Recessed portion, 51 Core side tapered surface portion, 53 Curved surface portion.

Claims (11)

Tubular core,
A valve seat having a seat surface formed and arranged on the downstream side of the fuel flow with respect to the core;
A valve element disposed displaceably between the core and the seat surface, closing the fuel passage by contacting the seat surface, and opening the fuel passage by separating from the seat surface,
A cylindrical holder that houses the valve seat and the valve body,
A spring for urging the valve body in a direction of contacting the seat surface, and a coil for generating an electromagnetic attraction force that displaces the valve body in a direction away from the seat surface against the urging force of the spring.
The valve body has a cylindrical armature facing the core, and a valve body main body fixed to the armature,
The valve body is in contact with the seat surface by the displacement of the amateur in a direction away from the core, and is separated from the seat surface by the displacement of the amateur in a direction toward the core,
The end portion on the core side of the amateur is provided with a convex portion and a flat surface forming portion located radially outside of the convex portion,
The flat surface forming portion has a first orthogonal flat surface portion continuous from the convex portion,
The first orthogonal plane portion is parallel to a plane orthogonal to the axis of the amateur,
The convex portion projects toward the core from a position of the first orthogonal flat surface portion,
The outline of the convex portion in a plane including the axis of the amateur is an arc-shaped curve continuous from the inner peripheral surface of the amateur ,
A fuel injection valve in which, when the amateur is in contact with the core, the convex portion is in contact with the core at a point on the outline of the convex portion on a plane including the axis of the amateur .   The fuel injection valve according to claim 1, wherein the convex portion is arranged in an annular shape along the circumferential direction of the amateur.   The fuel injection valve according to claim 2, wherein the convex portion is provided with a concave portion. A plurality of the convex portions are provided at the end portion of the amateur on the core side,
The fuel injection valve according to claim 1, wherein the plurality of convex portions are arranged at intervals in the circumferential direction of the amateur.   The fuel injection valve according to claim 4, wherein the outer surface of each of the plurality of convex portions has a spherical surface shape. The plane forming portion has a second orthogonal plane portion located radially outside of the first orthogonal plane portion,
The second orthogonal plane portion is parallel to a plane orthogonal to the axis of the amateur,
The distance between the said 2nd orthogonal plane part and the said core is larger than the distance between the said 1st orthogonal plane part and the said core. The fuel injection valve described in.   A curved surface portion that smoothly connects the first orthogonal plane portion and the second orthogonal plane portion is provided between the first orthogonal plane portion and the second orthogonal plane portion. 6. The fuel injection valve according to item 6.   The armature side taper surface part which inclines in the direction which leaves | separates from the said core toward the radial direction outer side from the said plane formation part is provided in the end part by the side of the said core of the said amateur. The fuel injection valve according to one item.   The fuel injection valve according to claim 8, wherein a curved surface portion that smoothly connects the flat surface forming portion and the amateur side tapered surface portion is provided between the flat surface forming portion and the amateur side tapered surface portion. At the end on the amateur side of the core, a core side taper surface portion that is inclined inward in a radial direction of the core in a direction away from the amateur is provided,
The fuel injection valve according to any one of claims 1 to 9, wherein the convex portion faces the core-side tapered surface portion.   A curved surface portion that smoothly connects the convex portion and the first orthogonal flat surface portion is provided between the convex portion and the first orthogonal flat surface portion. The fuel injection valve according to one item.

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