Electromagnetic fuel injector and method for assembling the same

Abstract

An electromagnetic fuel injection valve comprising: a metallic cylindrical-shaped vessel provided at a tip end thereof with a fuel injection port, the other end thereof being closed by a stationary core provided centrally thereof with a through-hole; a movable member arranged between the stationary core and the fuel injection port and provided at a tip end thereof with a valve element, which opens and closes the fuel injection port, a maximum outside diameter of the movable member being smaller than a minimum inside diameter of the through-hole; and an electromagnetic drive mechanism that reciprocates the movable member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal, cross sectional view showing an electromagnetic fuel injection valve according to a first embodiment.

FIG. 2 is a partially enlarged, cross sectional view showing the electromagnetic fuel injection valve according to the first embodiment.

FIG. 3 is a partially enlarged, cross sectional view showing the electromagnetic fuel injection valve according to the first embodiment.

FIG. 4 is a view illustrating assembly of the electromagnetic fuel injection valve according to the first embodiment.

FIG. 5 is a view illustrating assembly of the electromagnetic fuel injection valve according to the first embodiment.

FIG. 6 is a view illustrating assembly of the electromagnetic fuel injection valve according to the first embodiment.

FIG. 7 is a view illustrating assembly of the electromagnetic fuel injection valve according to the first embodiment.

FIG. 8 is a view illustrating assembly of the electromagnetic fuel injection valve according to the first embodiment.

FIG. 9 is a view illustrating assembly of the electromagnetic fuel injection valve according to the first embodiment.

FIG. 10 is a view illustrating assembly of the electromagnetic fuel injection valve according to the first embodiment.

FIG. 11 is a longitudinal, cross sectional view showing an electromagnetic fuel injection valve according to a second embodiment.

FIG. 12 is a longitudinal, cross sectional view showing the electromagnetic fuel injection valve according to the third embodiment.

Claims

1. An electromagnetic fuel injection valve comprising: a metallic cylindrical-shaped vessel provided at a tip end thereof with a fuel injection port, the other end thereof being closed by a stationary core provided centrally thereof with a through-hole;a movable member arranged between the stationary core and the fuel injection port and provided at a tip end thereof with a valve element, which opens and closes the fuel injection port, a maximum outside diameter of the movable member being smaller than a minimum inside diameter of the through-hole; andan electromagnetic drive mechanism that reciprocates the movable member.

2. An electromagnetic fuel injection valve according to claim 1, further comprising a guide element fixed to an inner periphery of the metallic cylindrical-shaped vessel between the stationary core and the fuel injection port and provided centrally thereof with a hole, by which the movable member is guided.

3. An electromagnetic fuel injection valve according to claim 2, wherein the electromagnetic drive mechanism comprises an anchor facing the stationary core to cooperate with the stationary core to reciprocate, and the anchor is provided centrally thereof with a through-hole, through which the movable member is inserted, and the movable member comprises an engagement portion that engages with an engagement surface of the anchor on a side of the stationary core around the through-hole, and an outside diameter of the engagement portion is larger than an outside diameter of that portion of the movable member, which is guided by the guide element.

4. An electromagnetic fuel injection valve according to claim 1, further comprising a spring mounted in the through-hole to push a rear end of the movable member, and a regulator that regulates a position of the spring.

5. An electromagnetic fuel injection valve according to claim 1, wherein the movable member is made of a non-magnetic material or a weak magnetic material wholly or partially in the vicinity of a magnetic path formed by the electromagnetic drive mechanism, or subjected to a processing of non-magnetization or weak magnetization.

6. An electromagnetic fuel injection valve according to claim 1, wherein the metallic cylindrical-shaped vessel is made of a non-magnetic material or a weak magnetic material wholly or partially in the vicinity of a magnetic path formed by the electromagnetic drive mechanism, or subjected to a processing of non-magnetization or weak magnetization.

7. A method of assembling an electromagnetic fuel injection valve, comprising: mounting a stationary core, which is provided centrally thereof with a through-hole, into an inner periphery of an end of a metallic cylindrical-shaped vessel and provided at a tip end thereof with a fuel injection port;thereafter assembling a movable member provided at a tip end thereof with a valve element, which opens and closes the fuel injection port, through the through-hole; andfurther assembling a spring, which pushes a rear end of the movable member, and a regulator in this order into the through-hole.

8. An electromagnetic fuel injection valve comprising: a metallic cylindrical-shaped vessel provided at a tip end thereof with a fuel injection port, the other end thereof being closed by a stationary core provided centrally thereof with a through-hole;a movable member provided at a tip end thereof with a valve element, which opens and closes the fuel injection port, and extending to the fuel injection port from the stationary core; andan electromagnetic drive mechanism that reciprocates the movable member, andwherein a maximum outside diameter of the movable member is smaller than a minimum inside diameter of the through-hole.

9. A method of assembling the electromagnetic fuel injection valve according to claim 8, wherein after the stationary core is mounted to the metallic cylindrical-shaped vessel, the movable member is assembled through the through-hole, and a spring and a regulator are assembled in this order to the through-hole above the movable member.

10. An electromagnetic fuel injection valve comprising: a metallic cylindrical-shaped vessel including a small-diameter cylindrical-shaped portion at one end thereof and a large-diameter cylindrical-shaped portion at the other end thereof;a fuel injection port provided at a tip end of the small-diameter cylindrical-shaped portion;a stationary core fixed to an interior of the large-diameter cylindrical-shaped portion;an electromagnetic drive mechanism comprising an electromagnetic coil device provided on an outer periphery of the large-diameter cylindrical-shaped portion and an anchor spring-loaded in a direction away from the stationary core and attracted by the stationary core upon energization of the electromagnetic coil device;a movable member accommodated between the stationary core and the fuel injection port and caused by movements of the anchor of the electromagnetic drive mechanism to reciprocate between the stationary core and the fuel injection port; anda valve element provided at a tip end of the movable member to open and close the fuel injection port, andwherein the movable member is inserted through a through-hole provided on the anchor to extend to the fuel injection port, and a head thereof is inserted through a through-hole provided on the stationary core,a maximum outside diameter of the movable member except the head is smaller than minimum inside diameters of through-holes provided on the stationary core and the anchor, and a maximum outside diameter of the head is larger than a minimum inside diameter of the through-hole provided on the anchor and smaller than a minimum inside diameter of the through-hole provided on the stationary core.

11. An electromagnetic fuel injection valve according to claim 10, wherein the electromagnetic coil device comprises: a cup-shaped yoke fixed to an outer periphery of the large-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel;an annular-shaped coil provided between the outer periphery of the large-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel and an inner periphery of the cup-shaped yoke; andan annular yoke that closes an opened end side of the cup-shaped yoke.

12. An electromagnetic fuel injection valve according to claim 10, wherein the stationary core is formed on an outer periphery thereof with an annular flange, and one side end surface of the flange and an end surface of the large-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel abut against each other to be fixed together.

13. An electromagnetic fuel injection valve according to claim 10, wherein the stationary core is formed on an outer periphery thereof with an annular flange, and one side end surface of the flange and an end surface of the large-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel face or abut against each other to be fixed together, andone side end surface of the annular yoke is positioned so as to be made flush with the other side end surface of the flange of the stationary core and fixed to an outer periphery of the flange.

14. An electromagnetic fuel injection valve according to claim 10, wherein the metallic cylindrical-shaped vessel is formed as an integral body from the same member, and the large-diameter cylindrical-shaped portion is smaller in wall thickness than the small-diameter cylindrical-shaped portion,the small-diameter cylindrical-shaped portion is formed integrally at a tip end thereof with a portion, which is larger in wall thickness than the remaining portions, andthe portion having a large wall thickness is formed on an outer periphery thereof with a groove, to which a sealing member is mounted.

15. An electromagnetic fuel injection valve according to claim 10, wherein the metallic cylindrical-shaped vessel is formed as an integral body from the same member, the small-diameter cylindrical-shaped portion is formed integrally at a foremost tip end thereof with a cylindrical-shaped portion, which is smaller in wall thickness than any portion of the metallic cylindrical-shaped vessel, anda guide element including a guide hole, by which a tip end of the movable member is guided, and an orifice plate provided with the fuel injection port are assembled in this order to the cylindrical-shaped portion.

16. An electromagnetic fuel injection valve according to claim 10, wherein the large-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel includes an annular groove on an outer periphery of a portion thereof, about which the stationary core and the anchor face each other.

17. An electromagnetic fuel injection valve according to claim 10, wherein an outer periphery of the stationary core is formed to be cylindrical-shaped to be fixed to an inner periphery of the large-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel, the stationary core has an end surface on one end side thereof facing the anchor and is formed on an end surface on the other side thereof with a projecting cylindrical-shaped portion having a smaller outside diameter than an inside diameter of the large-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel,a fuel passage is formed on a center of the stationary core that includes the projecting cylindrical-shaped portion, anda first spring, which applies to the movable member a preload in a direction, in which the fuel injection port is closed, and a regulator, which regulates the preload, are mounted in the fuel passage.

18. An electromagnetic fuel injection valve according to claim 17, further comprising a fuel introduction pipe fixed to an outer periphery of the projecting cylindrical-shaped portion, and a resin compact that covers an end surface of the large-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel, an axial end surface of the electromagnetic coil device, an axial end surface of the stationary core, the projecting cylindrical-shaped portion, and a periphery of the fuel introduction pipe and molds therein an electric terminal of the electromagnetic coil device.

19. An electromagnetic fuel injection valve according to claim 18, wherein the projecting cylindrical-shaped portion is formed on an outer periphery thereof with a flange, which bears the axial end surface of the fuel introduction pipe, and the flange is larger in outside diameter than the projecting cylindrical-shaped portion and the fuel introduction pipe.

20. An electromagnetic fuel injection valve according to claim 17, wherein the movable member includes a plunger that couples the head and the valve element, the head of the movable member reciprocates in a through-hole provided on the stationary core and is spring-loaded by the first spring,the anchor is born by an end of a second spring, the other end of which is held by the metallic cylindrical-shaped vessel, and arranged around the plunger to be reciprocatble, andthe anchor is interposed between the head of the movable member spring-loaded by the first spring and the second spring to cooperate with the movable member in axial movement.

21. An electromagnetic fuel injection valve according to claim 20, further comprising a plunger guide, an outer periphery of which is press fitted into an inner periphery of the large-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel, and which is formed centrally thereof with a guide hole, by which an outer periphery of the plunger is guided, and wherein the plunger guide holds an end of the second spring.

22. An electromagnetic fuel injection valve according to claim 21, further comprising a drawn portion on that outer periphery of the large-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel, which corresponds to a press-fitted position of the plunger guide.

23. An electromagnetic fuel injection valve according to claim 20, wherein the valve element formed from a separate member is fixed to a tip end of the plunger.

24. An electromagnetic fuel injection valve according to claim 23, wherein the plunger is formed from a hollow member.

25. An electromagnetic fuel injection valve according to claim 20, wherein the head, the plunger, and the valve element are formed from the same member.

26. An electromagnetic fuel injection valve according to claim 20, wherein the head is formed from a member separate from the plunger and fixed to the plunger.

27. An electromagnetic fuel injection valve according to claim 10, wherein a nozzle body formed as a separate body is mounted to the small-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel, the nozzle body is provided on one end side thereof with an insertion cylindrical-shaped portion, which is inserted into an inner periphery of the small-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel, and is provided on the other end side thereof with a tip end cylindrical-shaped portion, to which a guide element including a guide hole, by which a tip end of the movable member is guided, and an orifice plate provided with the fuel injection port are assembled in this order.

28. An electromagnetic fuel injection valve according to claim 27, wherein the nozzle body includes an annular groove permitting a sealing member to be mounted to an outer periphery thereof between the insertion cylindrical-shaped portion and the tip end cylindrical-shaped portion.

29. An electromagnetic fuel injection valve according to claim 28, wherein a portion of the nozzle body except the insertion cylindrical-shaped portion, the tip end cylindrical-shaped portion, and the annular groove is larger in wall thickness than both the large-diameter cylindrical-shaped portion and the small-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel.

30. An electromagnetic fuel injection valve according to claim 10, wherein an end surface of the large-diameter cylindrical-shaped portion, an axial end surface of the electromagnetic coil device, and an axial end surface of the stationary core are positioned on the same plane.

31. An electromagnetic fuel injection valve comprising: an anchor caused by an electromagnetic force generated by an electromagnetic coil device to cooperate with a stationary core to reciprocate; anda movable member caused by movement of the anchor to reciprocate between the stationary core and a fuel injection port, andthe fuel injection port is opened and closed by a valve element provided at a tip end of the movable member, andfurther comprising a metallic cylindrical-shaped vessel including a large-diameter cylindrical-shaped portion having the stationary core fixed to an interior thereof and having the electromagnetic coil device mounted to an outer periphery thereof, and a small-diameter cylindrical-shaped portion provided at a tip end thereof with the fuel injection port.

32. An electromagnetic fuel injection valve according to claim 31, wherein the large-diameter cylindrical-shaped portion and the small-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel are formed as a part of an integral body from the same member, and the large-diameter cylindrical-shaped portion is smaller in wall thickness than the small-diameter cylindrical-shaped portion, the small-diameter cylindrical-shaped portion is formed integrally at a tip end thereof with a portion, which is larger in wall thickness than the remaining portions, andthe small-diameter cylindrical-shaped portion is formed integrally at a foremost tip end thereof with a cylindrical-shaped portion, which is smaller in wall thickness than any portion of the metallic cylindrical-shaped vessel, anda guide element including a guide hole, by which a tip end of the movable member is guided, and an orifice plate provided with the fuel injection port are assembled in this order to the cylindrical-shaped portion.

33. An electromagnetic fuel injection valve according to claim 32, wherein the portion having a large wall thickness is formed on an outer periphery thereof with a groove, which permits a sealing member to be mounted.

34. An electromagnetic fuel injection valve according to claim 31, wherein the large-diameter cylindrical-shaped portion of the metallic cylindrical-shaped vessel includes an annular groove on an outer periphery of a portion thereof, about which the stationary core and the anchor face each other.

35. A method of assembling the electromagnetic fuel injection valve according to claim 31, the method comprising the steps of: forming a fuel injection port on an end of a metallic cylindrical-shaped vessel provided on one side thereof with a small-diameter cylindrical-shaped portion and on the other side thereof with a large-diameter cylindrical-shaped portion,mounting a combination of a stationary core and an anchor in the large-diameter cylindrical-shaped portion,fixing an electromagnetic coil device to an outer periphery of the large-diameter cylindrical-shaped portion,molding an electric terminal of the electromagnetic coil device and a part of the stationary core with a resin,assembling a movable member through through-holes of the stationary core and the anchor, andregulating the movable member in stroke.