JP2009243322A - Fuel injection valve and machining method of guide member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive fuel injection valve which enables the accurate and stable injection of fuel and excellent durability. <P>SOLUTION: In a fuel injection valve which includes a valve element 11, a drive means for driving the valve element, a valve seat 15a for accommodating the valve element, a guide member 17 provided on the upstream side of the valve seat, a nozzle 9 provided on the downstream side of the valve seat, and an orifice 22 formed at the tip of the nozzle to inject fuel, a cylindrical guide 42 and introduction part 43 are formed in a guide hole of the guide member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel injection valve that injects fluid, and more particularly, to a holding guide member that can slide a valve body, a method for processing the guide member, and a fuel injection valve using the same.

  Conventionally, an example in which a valve body guide member is provided on the upstream side of a valve seat is disclosed in Japanese Patent Laid-Open No. 11-200993 (Patent Document 1). The guide member (swivel body) disclosed in Patent Document 1 is press-fitted and fixed to the housing together with the valve seat, and after the valve seat and the housing are welded, the center hole is finished by grinding. It was.

Japanese Patent Laid-Open No. 11-200993

  However, in the technique disclosed in Japanese Patent Laid-Open No. 11-200993 (Patent Document 1), the center hole of the swivel body is cylindrical and the length of the center hole is about twice the diameter ( If a certain degree of thickness (length) is required to secure the press-fitting strength between the container and the swivel body), if excessive sliding resistance occurs in the valve body, or if the valve body or center hole is tilted There was a problem with the guide structure, such as difficulty in securing the oil tightness of the valve seat and the valve body.

  Further, since the center hole of the revolving structure is finished by grinding after assembling, there is a problem that not only the machining time is long but also grinding burrs are generated, and deburring is difficult.

  Furthermore, the surface state of the center hole becomes a circumferential tool mark due to grinding, and is perpendicular to the operating direction of the valve body, which causes an increase in sliding resistance and easy wear.

  In order to solve the above-described problems, an object of the present invention is to provide an introduction portion of a valve body in a guide hole of a guide member and minimize the length of the guide portion.

  It is another object of the present invention to improve productivity by squeezing the guide hole in the axial direction and finishing the surface of the guide portion into an axial tool mark.

  A representative one of the fuel injection valves according to the present invention includes a valve body, a driving means for driving the valve body, a valve seat that accommodates the valve body, and a guide provided on the upstream side of the valve seat. A fuel injection valve provided with a member, a nozzle provided on the downstream side of the valve seat, and an orifice provided at the tip of the nozzle for injecting fuel, wherein the guide hole of the guide member has a cylindrical guide A part and an introduction part are formed.

  In addition, a representative one of the finishing methods of the guide hole according to the present invention includes a step of preparing a blank in which the guide hole of the guide member is processed into a cylindrical shape, and the end surface side of the guide hole is tapered or curved. It has a step of press-molding into a shape and a step of finishing by squeezing the guide hole.

  ADVANTAGE OF THE INVENTION According to this invention, since a valve body operate | moves smoothly, the responsiveness is good and the fuel injection valve which injects a fuel accurately and stably can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a longitudinal sectional view showing the overall configuration of a fuel injection valve according to an embodiment of the present invention.

  The fuel injection valve main body 1 includes a magnetic circuit including a core 2, a yoke 3, a housing 4, and a mover 5, a coil 6 for exciting the magnetic circuit, and a terminal bobbin 7 for energizing the coil 6. A seal ring 8 is coupled between the core 2 and the housing 4 to prevent fuel from flowing into the coil 6.

  Valve parts are housed inside the housing 4, and a movable element 5, a nozzle 9, and a ring 10 that adjusts the stroke amount of the movable element 5 are arranged. The movable element 5 is obtained by connecting the valve body 11 and the movable core 12 with a joint 13, and suppresses the bounce when the movable element 5 is closed in cooperation with the pipe 18 between the movable core 12 and the joint 13. A plate 14 is provided.

  The housing 4 and the nozzle 9 constituting the jacket member cover the periphery of the movable element 5. The nozzle 9 slides the movable element 5 together with the orifice plate 15 having the sheet surface 15 a and the orifice 22 at the tip, and the guide plate 16. A swirler 17 is provided that movably guides and applies a turning force to the fuel.

  Inside the core 2 are disposed a spring 19 for pressing the valve element 11 against the seat surface 15a via the pipe 18 and the plate 14, an adjuster 20 for adjusting the pressing load of the spring 19, and a filter 21 for preventing contamination from entering from the outside. Has been.

  Next, the operation of the fuel injection valve body 1 will be described in detail.

  When the coil 6 is energized, the mover 5 is attracted in the direction of the core 2 against the urging force of the spring 19, and a gap is formed between the valve seat portion 11a at the tip of the mover 5 and the seat surface 15a (opening). Valve state). The pressurized fuel first enters the nozzle 9 from the core 2, the adjuster 20, and the pipe 18 through the fuel passage 13 a in the mover 5. Next, the fuel passage 16 a of the guide plate 16 and the passage 9 a of the nozzle enter the passages 17 a and 17 b of the swirler 17, and a turning force is given by the turning groove 17 c of the swirler 17. The fuel given the turning force is injected through the orifice 22 from the gap between the valve seat portion 11a and the seat surface 15a.

  On the other hand, when the current of the coil 6 is interrupted, the valve seat portion 11a of the mover 5 is brought into contact with the seat surface 15a by the force of the spring 19, and the valve is closed.

  Next, the swirler (guide member) 17 of the fuel injection valve body 1 will be described in detail.

  FIG. 2 is a sectional view of the swirler 17 according to the first embodiment of the present invention.

  The swirler 17 has a guide portion 42 of a guide hole 41 that slidably holds the valve body 11 in the center, and a curved introduction portion 43 is formed on the upstream side thereof. The swirler 17 also serves as a guide member. Further, a fuel passage 17a is formed on the upstream end face, and a swirl groove 17c that gives a turning force to the fuel to atomize the fuel is formed on the downstream end face.

  Here, since the mover 5 is slidably held at the two points of the guide plate 16 and the swirler 17, it is preferable that the length of the guide portion 42 in the axial direction is as short as not to cause abnormal wear. For example, since the guide hole 41 is 2 mm in this embodiment, the length of the guide portion 42 is preferably 2 mm or less, which is equal to or less than the guide hole 41. In consideration of abnormal wear, the minimum length is preferably 0.5 mm or more, and the length of the guide portion 42 should be set between 0.5 and 2 mm.

  On the other hand, in order to firmly fix the swirler 17 to the nozzle 9, a larger thickness is advantageous. In addition, a certain degree of rigidity is required to fulfill the function of the swirler 17 as a guide member, and a larger thickness is advantageous.

  In order to satisfy the above contradictory requirements, means for providing a step in the inner diameter can be considered, but a smooth curved surface or tapered introduction portion is more preferable in the following points.

  In other words, the wedge effect of the introduction portion forces the fuel to flow into the sliding portion, forming a liquid film and improving the wear resistance, and also the valve body 11 is floated by the liquid film, so the coaxiality with respect to the seat surface 15a. And the homogeneity of the spray is improved.

  FIG. 3 is a sectional view of the swirler 50 according to the second embodiment of the present invention. In the swirler 50 of FIG. 3, the guide part 52 is located in the center part of the guide hole 51, the introduction part 53 is provided in the upstream, and the introduction part 54 is provided in the downstream. The effect of the present swirler 50 is the same as the swirler 17 of FIG. Although not shown, the same effect can be obtained by providing an introduction portion only on the downstream side.

  Next, a method for manufacturing the guide hole 41 will be described.

  FIG. 4 shows a blank shape before finishing the guide hole 41, and FIG. 5 shows a process chart of finishing.

  First, a swirler blank 17a is prepared in which a part other than the cylindrical guide hole 41a is finished to a predetermined dimension by machining such as cutting, sintering, or pressing.

  Next, as shown on the right side of FIG. 5, the punch 31 provided with the peeping part 32a, the guide part 32b, the squeezing part 32c, and the forming part 33 is pressurized in the axial direction of the swirler blank 17a and shown on the left side of FIG. Thus, the punch 31 is processed to a predetermined position.

  By processing in this way, the guide part 42 and the introduction part 43 can be finished by a single molding.

  FIG. 6 shows the results of experiments on the optimum value of the ironing amount in order to finish the guide portion 42 with an accuracy of several μm.

  While the ironing amount is about 0.01, the springback amount (springback amount = punch diameter−inner diameter after ironing) increases in correlation with the ironing amount. However, when it is about 0.02 (1% in processing rate) or more, it becomes a substantially constant value. That is, the inner diameter becomes constant following the dimension of the ironing portion 32c of the punch 31.

  On the other hand, if the ironing amount exceeds 0.04 (2% in processing rate), deformation of the outer diameter (φ6.5) becomes large (about 0.005), so the ironing amount is 0.04 (2% in processing rate). The following is desirable.

  For parts that do not require the accuracy of the outer diameter, the inner diameter accuracy does not change even at a processing rate of 2% or more.

  FIG. 7 shows the relationship between the inner diameter dimensions of the guide hole 41 before and after ironing. Regardless of the dimension φd1 before ironing, the dimension φd0 after ironing is constant, and the variation of the guide part 42 is 0.001 or less and finishing can be performed with high accuracy.

  Moreover, not only the surface roughness of the inner diameter can be improved by ironing, but also the tool mark in the axial direction can be formed, so that sliding resistance and wear can be reduced. Furthermore, since the surface of the inner diameter of the raw material can be work-hardened, the life of the sliding portion can be improved.

  As described above, according to each embodiment of the present invention, it is possible to provide an inexpensive fuel injection valve that can stably and accurately inject fuel and has good durability.

  Although the embodiments of the present invention have been specifically described above, the present invention is not limited to these embodiments, and various modifications can be made within the scope of the inventive idea. For example, in the above embodiment, the introduction portion 43 has a curved surface shape, but may have a tapered shape, or a combined shape of a curved surface and a taper.

  Moreover, in the said Example, although the guide hole 42 and the introduction part 43 were shape | molded by one process, you may divide separately.

  Furthermore, although the swirler 17 was demonstrated, it is not restricted to a swirler, It can apply to any guide components.

1 is a longitudinal sectional view showing the overall configuration of a fuel injection valve showing a first embodiment of the present invention. The longitudinal cross-sectional view of the swirler which shows 1st Example of this invention. The longitudinal cross-sectional view of the swirler which shows 2nd Example of this invention. The longitudinal cross-sectional view of the swirler blank which shows 1st Example of this invention. The longitudinal cross-sectional view which shows the press work process of the swirler which shows 1st Example of this invention. The graph which shows the relationship between the amount of ironing and the amount of springback. The graph which shows the relationship between the internal diameter before ironing, and the internal diameter dimension after ironing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel injection valve main body 17 Swirler 31 Punch 32c Ironing part 33 Molding part 41 Guide hole 42 Guide part 43 Introduction part

Claims (6)

A movable valve body, a driving means for driving the valve body, a valve seat that houses the valve body, and a guide member that is positioned upstream of the valve seat and that slidably holds the valve body When,
A fuel injection valve provided with a nozzle provided on the downstream side of the valve seat and an orifice provided at a tip of the nozzle for injecting fuel;
The fuel injection valve according to claim 1, wherein the guide hole of the guide member is formed by a cylindrical guide portion and an introduction portion that spreads toward the end surface of the guide member. The fuel injection valve according to claim 1, wherein
The fuel injection valve, wherein the introduction portion has a curved surface shape or a tapered shape. The fuel injection valve according to claim 1, wherein
The fuel injection valve, wherein the introduction portion is formed on one side or both sides of the guide member. The fuel injection valve according to claim 1, wherein
The fuel injection valve, wherein the introduction portion and the guide portion are smoothly connected. A method of processing a guide member for guiding a valve body of a fuel injection valve,
A step of preparing a blank in which the guide hole of the guide member is processed into a cylindrical shape, a step of press-molding the end face side of the guide hole into a curved shape or a tapered shape, and a step of finishing the guide hole by squeezing A method of processing a guide member for a fuel injection valve, comprising: In the processing method of the guide member of the fuel injection valve according to claim 5,
A fuel injection valve characterized in that the step of press-molding the end face side of the guide hole into a curved shape or a tapered shape and the step of finishing the guide hole by ironing are processed in one step with one punch. Processing method of guide member.

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