JP4597908B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve, and more particularly to a technique for improving the durability of an elastic body that is provided for shock reduction during opening and closing operations of a valve body.

  A fuel injection valve provided with an elastic body for shock reduction is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-87826 (Patent Document 1). The fuel injection valve described in the publication includes an injection nozzle having an injection hole for injecting fuel, and a valve body for opening and closing the injection hole. The valve body closes the injection hole when the tip surface thereof abuts against the wall surface (seat surface) of the injection nozzle, and opens the injection hole when separated from the wall surface of the injection nozzle. An elastic body such as rubber as a sealing member is attached to the front end surface of the valve body, and shocks when the front end of the valve body abuts against the wall surface of the injection nozzle are buffered. In the fuel injection valve described in the publication, after the elastic body contacts the wall surface of the injection nozzle, the tip surface of the valve body contacts the wall surface of the injection nozzle. Thereby, excessive compression of the elastic body is restricted, and the durability of the elastic body is improved.

FIG. 7 shows a configuration in which after the elastic body comes into contact with the wall surface of the injection nozzle, the tip surface of the valve body comes into contact with the wall surface of the injection nozzle. As shown in the figure, a circular (or annular) concave portion 11a is formed in the inner peripheral region of the distal end surface of the valve body 11, and an elastic body 13 is disposed in the concave portion 11a. An annular protrusion 13 a is provided on the distal end surface of the elastic body 13 so as to project at a predetermined height beyond the distal end surface of the valve body 11 toward the injection nozzle side (not shown).
By the way, the elastic body 13 is generally molded by using a mold in the concave portion 11a of the valve body 11. As shown in the schematic diagram of FIG. 8, the mold 15 is disposed to face the distal end surface of the valve body 11. The convex portion 15a of the mold 15 formed so as to correspond to the surface shape of the elastic body 13 to be molded is arranged so as to fit into the concave portion 11a of the valve body 11, but at this time, the concave portion of the valve body 11 is arranged. Between the inner peripheral surface of 11a and the outer peripheral surface of the convex part 15a of the metal mold | die 15, the clearance gap C which accept | permits both fitting is formed. For this reason, when the elastic body 13 is molded, a burr 17 (see FIG. 7) corresponding to the gap C is generated at the outer peripheral edge of the elastic body 13 . The burr 17 generated in this way swells with liquefied fuel when the fuel injection valve is used, and an excessive stress is applied due to contact with the wall surface of the injection nozzle by the opening / closing operation of the valve body 11. As a result, it peels off from the valve body 11 and may affect the sealing performance and flow rate.
JP 2000-87826 A

  This invention is made | formed in view of this point, and it aims at providing the technique effective in solving the peeling problem of the burr | flash of an elastic body in a fuel injection valve.

In order to achieve the above object, the invention described in each of the claims is configured.
A fuel injection valve according to a first aspect of the present invention includes an injection nozzle having an injection hole for injecting fuel, and a valve body for opening and closing the injection hole by contacting or separating from the injection nozzle. One of the spray nozzles is provided with a contact portion and an elastic body, and the other is provided with a contact surface. And when a valve body moves to the direction which closes an injection hole, after an elastic body contact | abuts to a contact surface, it is set as the structure which a contact part contact | abuts to a contact surface. The “elastic body” in the present invention typically corresponds to rubber, and suitably includes both an aspect formed in a disc shape and an aspect formed in an annular shape.
In the present invention, as a characteristic configuration, one of the valve body and the injection nozzle is provided with an attachment surface in a direction away from the contact surface from the contact portion with the contact surface of the contact portion. An elastic body is attached to a recess formed on the surface.

  According to the present invention, the attachment surface is provided in one of the valve body and the injection nozzle in a direction away from the contact surface from the contact portion with the contact surface of the contact portion. And the elastic body is attached to the recessed part formed in the contact surface. For this reason, even if the elastic body swells due to the fuel and the outer peripheral area of the end surface facing the contact surface protrudes from the mounting surface, the protruding portion contacts the contact surface during the opening / closing operation of the valve body. There is no problem of peeling due to contact. Thereby, the malfunction which arises due to the peeling | exfoliation of the burr | flash which arose in the outer peripheral area | region of the end surface of an elastic body is eliminated, and the influence on the sealing performance regarding fuel injected from an injection nozzle, or flow volume can be avoided.

According to the present invention, the concave portion has a circular shape. The elastic body is formed in a disc shape and has an annular seal portion protruding toward the contact surface. When the valve body is moved in the direction to close the injection hole, the annular seal portion comes into contact with the contact surface and elastically deforms before the contact portion comes into contact with the contact surface. Close the injection hole. Thereby, an injection hole can be sealed reliably. According to the present invention, since the elastic body is formed in a plate shape, for example, the surface shape, that is, the shape of the mating surface of the mold is simplified compared to the case where the elastic body is formed in an annular shape, which is effective in reducing the manufacturing cost. is there.

According to the present invention, the elastic body, around the outside of the sealing portion, is configured to have a periphery region formed on the mounting surface flush with a step with respect to the contact portion. In the present invention, “level” generally includes level. In the present invention, by forming the mounting surface and the outer peripheral region of the elastic body approximately flush with each other, for example, when molding an elastic body of a predetermined shape by combining a mold with one of the valve body or the injection nozzle, With respect to the molding region of the elastic body, it is possible to eliminate a step in the butting direction on the mating surface of the valve body or the injection nozzle and the mold. That is, with respect to the molding region of the elastic body, a portion where the valve body or the injection nozzle and the mold are fitted can be eliminated. For this reason, no burrs are generated in the outer peripheral area of the elastic body facing the contact surface, which eliminates the problems caused by the detachment of burrs, and seals and flow rate of fuel injected from the injection nozzle The influence on can be avoided. Further, since the elastic body has an outer peripheral region formed substantially flush with the mounting surface around the outer periphery of the seal portion, the load at the time of elastic deformation of the seal portion is applied to the joint between the mounting surface and the outer peripheral region. Concentration can be avoided reasonably and the peeling action of the elastic body can be reduced.

(Invention of Claim 2)
According to the second aspect of the present invention, the contact portion of the fuel injection valve according to the first aspect is an annular protrusion, and the mounting surface is formed inside the annular protrusion. The “annular protrusion” in the present invention suitably includes both an aspect in which the periphery of the attachment surface is continuously surrounded or an aspect in which the periphery is intermittently provided around the attachment surface. According to the present invention, when the valve body moves in the direction of closing the injection hole, the annular protrusion arranged around the elastic body contacts the contact surface after the elastic body contacts the contact surface. The closing position of the valve body is defined by contact. Thereby, it can avoid that an excessive load acts on an elastic body, and can improve the durability of an elastic body.

(Invention of Claim 3)
According to invention of Claim 3, the elastic body in the fuel injection valve of Claim 1 or 2 is set as the structure provided in the valve body. ADVANTAGE OF THE INVENTION According to this invention, the technique effective in preventing the problem of peeling by contact | abutting in the valve body side is provided.

  According to the present invention, in the fuel injection valve, a technique effective for solving the problem of peeling of the burrs of the elastic body is provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows the overall configuration of an electromagnetic fuel injection valve for LP gas (liquefied petroleum gas) according to the present embodiment, and FIG. 2 shows an enlarged view of part A in FIG. As shown in FIG. 1, the electromagnetic fuel injection valve 100 has a main body 110 extending in the axial direction. The main body 110 is formed in a substantially cylindrical shape, and the cylindrical hole 111 constitutes a fuel passage for LP gas (hereinafter referred to as fuel). A cylindrical fixed core 133 and a needle valve 113 that constitute a fixed iron core of the magnetic circuit are disposed in the cylindrical hole 111 of the main body 110. The fixed core 133 is fixed to the main body 110. The needle valve 113 includes a cylindrical member 114 made of a magnetic material that is slidable in the axial direction with respect to the main body 110, a cylindrical valve shaft 115 that moves together with the cylindrical member 114, and an axial tip of the valve shaft 115. And one end in the axial direction of the cylindrical member 114 is arranged opposite to the fixed core 133 with a predetermined gap in the axial direction.

  An injection nozzle 121 facing the tip of the valve body 116 of the needle valve 113 is disposed at one end of the main body 110 in the axial direction, that is, at the tip (see FIG. 2). The injection nozzle 121 has an injection hole 122 and is fixed to the main body 110. A coil spring 125 for valve closing is disposed in the cylindrical hole 133a of the fixed core 133, and the needle valve 113 is arranged at the tip of the valve body 116 by the coil spring 125 so that the nozzle seat surface 121a of the injection nozzle 121 (FIG. 5). (See)). That is, the valve body 116 of the needle valve 113 closes the injection hole 122 by contacting the nozzle sheet surface 121 a of the injection nozzle 121. The biasing force of the coil spring 125 can be adjusted by a cylindrical spring pin 127 disposed in the cylindrical member 112. A fuel passage is constituted by the cylindrical hole 127a of the spring pin 127, the cylindrical hole 133a of the fixed core 133, the cylindrical hole 114a of the cylindrical member 114 of the needle valve 113, and the cylindrical hole 115a of the valve shaft 115. The valve body 116 corresponds to the “valve body” in the present invention. The spray nozzle 121 corresponds to the “spray nozzle” in the present invention, and the nozzle sheet surface 121a corresponds to the “contact surface” in the present invention.

  The main body 110 is surrounded by a resin-made housing 131 except for both ends in the axial direction. A solenoid coil 135 is disposed in the housing 131 so as to surround the fixed core 133, and a valve driving mechanism for opening and closing the needle valve 113 is configured by the solenoid coil 135 and the fixed core 133. The solenoid coil 135 is connected to a power supply device via a connector 137, and the cylindrical member 114 of the needle valve 113 is attracted to the fixed core 133 by electromagnetic force generated by energizing the solenoid coil 135. Thereby, the valve body 116 of the needle valve 113 is separated from the nozzle sheet surface 121a of the injection nozzle 121, the injection hole 122 is opened, and fuel is injected.

  FIG. 3 shows a state in which the fuel injection valve 100 is connected to the delivery pipe 145 and the return pipe 149, and FIG. 4 is an enlarged view of a portion B in FIG. As shown in FIG. 3, the housing 131 of the fuel injection valve 100 and the tip portion of the main body 110 exposed from the housing 131 are accommodated by an inlet cover 141 formed in a substantially cylindrical shape. A fuel introduction passage 143 for introducing fuel is formed in the inlet cover 141, and a delivery pipe (fuel distribution pipe) 145 is connected to the fuel introduction passage 143.

  The fuel supplied from the delivery pipe 145 through the fuel introduction passage 143 passes through a filter 147 disposed between the inlet cover 141 and the main body 110 as shown in FIG. After flowing into the fuel introduction space C1 between the main body 110 and the valve shaft 115 of the needle valve 113 through the plurality of through holes 110a, the cylinder passes through the plurality of radial through holes 115b formed in the valve shaft 115. It flows into the hole 115a. The fuel that has flowed into the cylindrical hole 115a of the valve shaft 115 passes through a plurality of radial supply holes 115c formed at the tip of the valve shaft 115 in a state where the needle valve 113 is placed at the closed position, and then the valve body 116. The fuel flows into and accumulates in a fuel reservoir space C2 formed on the outer periphery of the fuel. The fuel reservoir space C2 is formed by a gap between the outer peripheral surface of the valve body 116 and the inner peripheral surface of the cylindrical portion 123 (see FIG. 5) formed in the injection nozzle 121 so as to surround the valve body 116. .

  Further, as shown in FIG. 3, the fuel that has flowed into the cylindrical hole 115 a of the valve shaft 115 has the cylindrical hole 114 a of the cylindrical member 114, the cylindrical hole 133 a of the fixed core 133, the cylindrical hole 117 a of the spinning pin 117, and the main body 110. It is configured to flow through the filter 148 to the flow path 149 a of the return pipe 149 connected to the open end of the main body 110 through the cylindrical hole 111. That is, the fuel supplied from the delivery pipe 145 to the fuel injection valve 100 is configured to return to the return pipe 149 through the internal fuel passage of the fuel injection valve 100 described above.

  The fuel injection valve 100 and the return pipe 149 are connected to the other end in the axial direction of the main body 110, that is, the rear end corresponding to the fuel outlet side, and the end of the housing 131 through the mounting hole 149b ( This is done by fastening the inlet cover 141 to the return pipe 149 with a screw (not shown) in a state of being fitted in the inside (see FIG. 3). Further, the outer peripheral surface of the main body 110 and the inner peripheral surface of the mounting hole 149b, the outer peripheral surface of the housing 131 and the inner peripheral surface of the inlet cover 141, and the outer peripheral surface of the main body 110 and the inlet cover. O-rings 151, 153, and 155 are interposed between the inner peripheral surface of 141, respectively, so that the fuel flowing into the fuel injection valve 100 is sealed so as not to leak to the outside. A cover 157 for attaching the fuel injection valve 100 to the engine (cylinder head or intake pipe) is disposed on the front end side of the fuel injection valve 100.

  Next, the configuration of the valve body 116 in the needle valve 113 of the present embodiment will be described in detail with reference mainly to FIG. As shown in FIG. 5, on the distal end surface of the valve body 116 (surface facing the nozzle sheet surface 121 a of the injection nozzle 121), the outer peripheral side projects toward the nozzle sheet surface 121 a centering on the axis of the valve body 116. An annular outer peripheral protrusion 116b is formed. In addition, a flat area 116a is formed on the inner side (inner peripheral side) of the outer peripheral protrusion 116b in a direction away from the nozzle sheet surface 121a from a contact portion of the outer peripheral protrusion 116b with the nozzle sheet surface 121a. A circular recess 117 in which the seal member 129 is disposed is formed inside the region 116a. That is, the front end surface of the valve body 116 has a two-stage structure of a planar region 116a and an outer peripheral protruding portion 116b having different axial heights in the outer peripheral region of the recess 117 where the seal member 129 is disposed. The outer peripheral projection 116b corresponds to the “contact portion” in the present invention, and the planar region 116a corresponds to the “mounting surface” in the present invention.

  A seal member 129 made of elastically deformable rubber or the like is inserted into the recess 117, and the nozzle sheet surface is inserted into the seal member 129 at a position that enters a predetermined amount from the outer peripheral region 129a on the surface facing the nozzle sheet surface 121a. An annular protrusion 129b protruding to the 121a side is formed. Further, the outer peripheral region 129a of the seal member 129 and the flat region 116a of the valve body 116 are substantially flush with each other. The seal member 129 corresponds to the “elastic body” in the present invention, the outer peripheral region 129a corresponds to the “outer peripheral region” in the present invention, and the annular protrusion 129b corresponds to the “seal portion” in the present invention.

  The protrusion height of the outer peripheral protrusion 116b of the valve body 116 from the flat area 116a is set lower than the protrusion height of the protrusion 129b of the seal member 129 from the outer peripheral area 129a. Therefore, when the needle valve 113 is operated in a direction to close the injection hole 122 of the injection nozzle 121, the outer peripheral protrusion 116b of the valve body 116 is elastically deformed by the protrusion 129b of the seal member 129 coming into contact with the nozzle seat surface 121a. Then, it contacts the nozzle sheet surface 121a. Thereby, it is avoided that an excessive load acts on the seal member 129.

  The fuel injection valve 100 in the present embodiment is configured as described above. When the seal member 129 is molded into the concave portion 117 of the valve body 116 using the mold 200 as shown in the schematic diagram of FIG. 6, the mating surface 201 with the valve body 116 of the mold 200 is the outer periphery of the valve body 116. It is formed in a shape corresponding to the axial end surface shape of the protruding portion 116b, the planar region 116a, and the axial end surface shape of the seal member 129 to be formed. Therefore, in a state where the mold 200 is abutted against the front end surface of the valve body 116, the mating surface of the valve body 116 and the mold 200 is a continuous flat surface with no step in the abutting direction with respect to the molding region of the seal member 129. To do.

  As described above, according to the present embodiment, the tip shape of the valve body 116 has a two-stage structure of the planar region 116a and the outer peripheral protruding portion 116b having different axial heights, and the planar region 116a and the seal member. By forming the outer peripheral region 129a of 129 substantially flush with each other, it is possible to eliminate a portion where the valve body 116 and the mold 200 are fitted to each other with respect to the molding region of the seal member 129. For this reason, it is possible to prevent burrs from being generated in the outer peripheral region of the end face of the seal member 129 formed in the recess 117, thereby eliminating the problem of burr peeling which has been a problem in the past. Further, since the seal member 129 has an outer peripheral region 129a that is substantially flush with the planar region 116a around the outer periphery of the annular protrusion 129b, the load when the annular protrusion 129b is pressed against the nozzle sheet surface 121a. However, it is possible to rationally avoid the concentration at the joint portion between the valve body 116 and the seal member 129. For this reason, the peeling effect | action from the valve body 116 of the sealing member 129 can be reduced.

  Further, according to the present embodiment, the front end surface of the valve body 116 provided with the seal member 129 has a two-stage structure of the planar region 116a and the outer peripheral protrusion 116b in the axial direction of the valve body 116. Even if the seal member 129 swells and the outer peripheral region 129a protrudes from the flat region 116a of the valve body 116, the protruding portion contacts the nozzle sheet surface 121a of the injection nozzle 121 facing when the valve body 116 is opened and closed. There is no contact, and there is no problem of peeling due to contact. Further, the elastic deformation of the protrusion 129b of the seal member 129 is defined by the outer peripheral protrusion 116b of the valve body 116 coming into contact with the nozzle sheet surface 121a of the injection nozzle 121, so that an excessive load acts on the seal member 129. This is effective in avoiding this and improving the durability of the seal member 129.

  Although the above-described embodiment has been described as the fuel injection valve 100 for LP gas (liquefied petroleum gas), it may be applied to a fuel injection valve that supplies fuel other than LP gas.

  In this embodiment, the seal member 129 is provided on the valve body 116 side. However, the seal member 129 may be provided on the injection nozzle 121 side. In that case, with respect to the nozzle sheet surface 121a of the injection nozzle 121, a planar region that is flush with the outer peripheral region 129a of the seal member 129, and an annular projecting portion that protrudes toward the valve body 116 from the planar region and has a higher axial direction. The tip surface of the valve body 116 is a flat surface.

  In the present embodiment, the planar region 116a of the valve body 116 and the outer peripheral region 129a of the seal member 129 have a flush structure without a step, but may be changed to a configuration having a step. Further, in the present embodiment, a case where a part of the fuel supplied from the delivery pipe 145 to the fuel injection valve 100 is returned to the return pipe 149 through the fuel passage in the fuel injection valve 100 has been described. Instead of the configuration, a fuel injection valve having a configuration in which the connection port with the return pipe 149 of the main body 110 is used as the fuel inlet, that is, the fuel is supplied from the rear end portion of the main body 110 and introduced into the valve body 116 at the front end. 100 may be applied.

It is sectional drawing which shows the whole structure of the fuel injection valve which concerns on this Embodiment. It is an expanded sectional view of the A section in FIG. It is sectional drawing which shows the connection structure of the fuel injection valve with respect to a delivery pipe and a return pipe. It is an expanded sectional view of the B section in FIG. It is an enlarged view which shows the attachment structure of the sealing member with respect to a valve body. It is a schematic diagram explaining shaping | molding of the sealing member with respect to a valve body. It is an enlarged view which shows the attachment structure of the sealing member with respect to the conventional valve body. It is a schematic diagram explaining shaping | molding of the sealing member with respect to a valve body.

DESCRIPTION OF SYMBOLS 100 Fuel injection valve 110 Main body 111 Cylinder hole 110a Through-hole 113 Needle valve 114 Cylinder member 114a Cylinder hole 115 Valve shaft 115a Cylinder hole 115b Through-hole 115c Supply hole 116 Valve body 116a Plane area | region (mounting surface)
116b Peripheral protrusion (contact portion)
117 Concave part 121 Injection nozzle 121a Nozzle sheet surface (contact surface)
122 injection hole 123 cylindrical part 125 coil spring 127 spring pin 127a cylinder hole 129 sealing member (elastic body)
129a Outer peripheral region 129b Projection (seal part)
131 Housing 133 Fixed core 133a Tube hole 135 Solenoid coil 137 Connector 141 Inlet cover 143 Fuel introduction passage 145 Delivery pipe 147 Filter 148 Filter 149 Return pipe 149a Channel 149b Mounting holes 151-155 O-ring 157 Cover 200 Mold 201 Matching surface C1 Fuel introduction space C2 Fuel accumulation space

Claims (3)

An injection nozzle having an injection hole for injecting fuel;
A valve body that opens and closes the injection hole by contacting or separating from the injection nozzle;
One of the valve body and the injection nozzle is provided with a contact portion and an elastic body, and the other is provided with a contact surface.
The fuel injection valve is configured such that when the valve body moves in a direction to close the injection hole, the contact portion contacts the contact surface after the elastic body contacts the contact surface. And
One of the valve body and the injection nozzle is provided with a mounting surface in a direction away from the contact surface from a contact portion with the contact surface of the contact portion, and is formed on the mounting surface. and Ri said elastic member is attached you in the recess,
The recess has a circular shape;
The elastic body is formed in a disc shape and has an annular seal portion that protrudes toward the contact surface.
The fuel injection valve according to claim 1, wherein the elastic body has an outer peripheral region formed on the outer periphery of the seal portion and flush with the mounting surface having a step with respect to the contact portion. The fuel injection valve according to claim 1,
The fuel injection valve according to claim 1, wherein the contact portion is an annular protrusion, and the mounting surface is formed inside the annular protrusion. The fuel injection valve according to claim 1 or 2,
The fuel injection valve according to claim 1, wherein the elastic body is provided in the valve body.

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