WO2021153052A1 - Fuel injection device - Google Patents

Abstract

The purpose of the present invention is to provide a fuel injection device capable of suppressing the influence on basic characteristics of the fuel injection device and improving the waterproof performance of a coil unit.　A fixed core 40 has a large diameter portion 40a that is located above a small diameter portion 40b and has an outer diameter larger than that of the small diameter portion 40b. A housing 70 has a recessed portion 250-1 formed to be recessed radially outward at a position of an inner peripheral surface 70a facing an outer peripheral surface 40aa of the large diameter portion 40a, the position overlapping an outer peripheral surface 40aa in an axial direction Da. The lowermost end 250b of the recessed portion 250-1 is located above the center 40AX of the large diameter portion 40a in the axial direction Da, and the uppermost end 250c of the recessed portion 250-1 is located below the upper end (upper end surface) 40ab of the large diameter portion 40aa in the axial direction Da.

Description

Fuel injection device

The present invention relates to a fuel injection device.

As a background technique in this technical field, a fuel injection device described in Japanese Patent Application Laid-Open No. 2017-82293 (Patent Document 1) is known. The fuel injection device of Patent Document 1 includes a fixed core, a movable core, a coil that generates a magnetic attraction force between the fixed core and the movable core when energized, and a coil located on the outer peripheral side of the coil. In a fuel injection device including a housing to be housed and a resin filled on the inner peripheral side of the housing to coat a coil, the housing is provided with a flat surface portion in a direction intersecting the central axis direction to roughen the surface of the flat surface portion. ing. (See summary).

Further, in the fuel injection valve of Patent Document 1, two flat surfaces are provided on the upper surface and the lower surface of the rectangular shape portion by providing the rectangular shape portion on the entire circumference of the inner peripheral surface below the upper end portion of the housing. (See paragraph 0057 and FIG. 4). In this case, by providing a plurality of rectangular shaped portions, more flat portions can be provided (see paragraph 0057 and FIG. 4).

According to the configuration of Patent Document 1, since a large area of the flat surface portion can be secured, it is possible to more reliably prevent the resin from coming off from the unevenness formed on the surface of the flat surface portion even against shrinkage after resin molding. Can be done (see paragraph 0060). Further, the path length to the coil can be secured against the ingress of water entering from the interface between the housing and the resin, and a more reliable waterproof structure can be obtained. (See paragraph 0061)

Japanese Unexamined Patent Publication No. 2017-82693

Fuel injection devices (sometimes called fuel injection valves) used in internal combustion engines are exposed to harsh environments such as water exposure and temperature cycles. Especially with regard to water exposure, under more severe conditions such as when the fuel injection device is submerged, water infiltrates the coil portion, an electric conduction path is formed between the inner peripheral surface of the housing and the coil, and the insulation resistance of the coil decreases. There is a risk that problems will occur. Therefore, it is desired to improve the waterproof performance of the coil portion.

In Patent Document 1, a plurality of rectangular shaped portions are provided on the inner peripheral surface of the housing so that the path length from the upper end portion of the housing to the coil can be lengthened against water intrusion from the interface between the housing and the resin. It has a highly reliable waterproof structure. However, in the fuel injection valve of Patent Document 1, a rectangular shape portion is provided up to the vicinity of the lower end portion of the large diameter portion (flange portion) of the fixed core. In this case, since the rectangular portion is provided to the extent that the magnetic characteristics are affected, the basic characteristics of the fuel injection device may be affected.

An object of the present invention is to provide a fuel injection device capable of suppressing the influence on the basic characteristics of the fuel injection device and improving the waterproof performance of the coil portion.

In order to achieve the above object, the fuel injection device of the present invention
A movable core, a fixed core having a small diameter portion located on the side of the movable core, a coil that generates a magnetic attraction between the fixed core and the movable core when energized, and a coil in the radial direction of the coil. A fuel injection device including a housing located on the outside and accommodating the coil, and a resin member filled inside the housing in the radial direction and covering the coil.
When the vertical direction in the axial direction of the fuel injection device is such that the side where the fixed core is arranged is the upper side and the side where the movable core is arranged is the lower side in the arrangement of the fixed core and the movable core.
The fixed core is located above the small diameter portion and has a large diameter portion having a larger outer diameter than the small diameter portion.
The housing has a recessed portion formed so as to be recessed outward in the radial direction at a position overlapping the outer peripheral surface in the axial direction on the inner peripheral surface facing the outer peripheral surface of the large diameter portion.
The lowermost end of the recess is located above the center of the large diameter portion in the axial direction.
The uppermost end of the recessed portion is located below the upper end of the large diameter portion in the axial direction.

Further, in order to achieve the above object, the fuel injection device of the present invention is used.
A movable core, a fixed core having a small diameter portion located on the side of the movable core, a coil that generates a magnetic attraction between the fixed core and the movable core when energized, and a coil in the radial direction of the coil. A fuel injection device including a housing located on the outside and accommodating the coil, and a resin member filled inside the housing in the radial direction and covering the coil.
When the vertical direction in the axial direction of the fuel injection device is such that the side where the fixed core is arranged is the upper side and the side where the movable core is arranged is the lower side in the arrangement of the fixed core and the movable core.
The fixed core is located above the small diameter portion and has a large diameter portion having a larger outer diameter than the small diameter portion.
The housing has a plurality of recesses formed on the inner peripheral surface so as to be recessed outward in the radial direction.
The lowermost portion of the recessed portion formed at the lowermost portion of the plurality of recessed portions is located above the center of the large diameter portion in the axial direction, and the uppermost end is located at the upper end of the large diameter portion in the axial direction. It is located on the lower side.

According to the present invention, it is possible to provide a fuel injection device capable of suppressing the influence on the basic characteristics of the fuel injection device and improving the waterproof performance of the coil portion.

Issues, configurations and effects other than those described above will be clarified by the explanation of the following embodiments.

FIG. 5 is a cross-sectional view including a central axis of the fuel injection device according to an embodiment of the present invention. An enlarged cross-sectional view showing the periphery of the housing and the coil of FIG. 1 in an enlarged manner. FIG. 2 is an enlarged cross-sectional view showing an enlarged vicinity of a rectangular shape portion formed on the inner peripheral surface of the housing of FIG. A radial enlarged cross-sectional view (IV-IV cross-sectional view) around the housing and coil of FIG. The figure explaining the flow of resin in the vicinity of a rectangular shape part. The figure explaining the shrinkage of a resin in the vicinity of a rectangular shape part.

Hereinafter, the fuel injection device 1 according to the embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view including a central axis of the fuel injection device 1 according to an embodiment of the present invention.

In this embodiment, the central axis AX1 of the fuel injection device 1 coincides with the central axis of each member of the nozzle body 10, the injection hole forming member 12, the valve body 20, the movable core 30, and the fixed core 40, and is the central axis. AX1 may be referred to as the central axis of each member 10, 12, 20, 30, and 40 for description.

In the following description, the vertical direction may be specified, but this vertical direction is based on the vertical direction in FIG. 1, and does not specify the vertical direction in the mounted state of the fuel injection device 1. Further, the end of the fuel injection device 1 on the side where the injection hole 11 is provided is called a tip, and the end on the opposite side is called a base end. The central axis AX1 is a line segment that is parallel to the central axis and passes through the central axis, and includes not only the central axis but also a line segment that extends the central axis. Further, the direction Da along the central axis AX1 will be referred to as an axis direction and will be described.

The fuel injection device 1 of the present embodiment includes a tubular nozzle body 10, an injection hole 11 provided at the tip of the nozzle body 10 in the axial direction, and a tip portion 23 extending in the axial direction to open and close the injection hole 11. It is provided with a valve body 20 having a valve body 20. Further, the fuel injection device 1 includes a movable core 30 that is engaged with the rear end portion 21 of the valve body 20 and moves in the axial direction together with the valve body 20, and a tubular fixed core 40 that attracts the movable core 30 by magnetic attraction. And a coil 50 that generates a magnetic attraction force in the fixed core 40. Here, the rear end portion 21 of the valve body 20 is an end portion on the proximal end side of the valve body 20.

Hereinafter, each part of the fuel injection device 1 of this embodiment will be described in more detail.

The fuel injection device 1 includes a coil bobbin 51 around which the coil 50 is wound, a coil spring 61 (first spring) that urges the valve body 20 in the valve closing direction, and an adjusting member 62 that adjusts the urging force of the coil spring 61. A small coil spring (second spring) 63 that urges the movable core 30 in a direction away from the injection hole 11 and the seat portion 124a (valve opening direction), a housing 70 that surrounds the outer peripheral side of the coil 50, and a connector 81. A resin portion (resin member) 80 integrally molded with the coil and a filter 90 for filtering the fuel are provided. Further, the nozzle body 10 has an injection hole forming member 12 at the tip end portion.

The nozzle body 10 is provided, for example, in a substantially cylindrical shape extending in the axial direction Da, and has an injection hole 11 at the tip portion. Inside the nozzle body 10, a round bar-shaped or columnar valve body 20 extending in the axial direction is inserted. The injection hole 11 is formed in the injection hole forming member 12 inserted into the tip end portion of the nozzle body 10. A groove 131 is formed on the outer peripheral surface of the tip of the nozzle body 10, and a combustion gas sealing member 15 is fitted in the groove 131.

The nozzle body 10 has a bottomed cylindrical internal space 140 having an opening that opens toward the base end side at the end portion (that is, the rear end portion) on the fixed core 40 side, and the internal space 140 has a bottomed cylindrical internal space 140. An annular movable core 30 is housed. A cylindrical recess 141 is further provided in the central portion of the bottom of the internal space 140, and one end of the small coil spring 63 is housed in the recess 141.

In the nozzle body 10, the tip of the stepped cylindrical fixed core 40 is press-fitted inside the opening of the internal space 140, and the nozzle body 10 and the fixed core 40 are joined by welding. As a result, the gap between the nozzle body 10 and the fixed core 40 is sealed, and the space inside the nozzle body 10 is sealed. A cylindrical coil bobbin 51 and a coil 50 wound around the coil bobbin 51 are arranged on the outer periphery of the tip of the nozzle body 10 and the fixed core 40, and a bottomed cylindrical shape is provided on the outer periphery thereof via a resin portion 80. Housing 70 is fixed.

The winding start and winding end ends of the coil 50 are connected to the power supply terminal 811 of the connector 81 of the resin portion 80 via wiring (not shown).

In the valve body 20, the seat portion 230 provided at the tip portion 23 comes into contact with the seat portion 124a of the seat surface 124 provided on the injection hole forming member 12, so that the fuel between the valve body 20 and the seat portion 124 is fueled. The flow path FC of the above is closed, and the injection hole 11 provided on the downstream side of the seat portion 124a is closed. Further, when the seat portion 232 is separated from the seat portion 124a of the seat surface 124, the fuel flow path FC is opened between the valve body 20 and the seat portion 124a, and the injection hole 11 is opened.

The fixed core 40 is a tubular member that attracts the movable core 30 by magnetic attraction. The fixed core 40 has a substantially cylindrical shape having irregularities on the outer peripheral surface.

The fixed core 40 is provided with a through hole 42 (in other words, coaxial with the central axis AX1) along the central axis AX1. The through hole 42 of the fixed core 40 forms a flow path FC for introducing fuel. The front end surface of the fixed core 40 faces the rear end surface (base end side end face) of the movable core 30, and the rear end surface (base end side end face) on the opposite side is provided with an opening 43 for introducing fuel. ..

The adjusting member 62 is press-fitted into the through hole 42 of the fixed core 40 and fixed inside the fixed core 40. The coil spring 61 is arranged in the through hole 42 of the fixed core 40, and urges the valve body 20 toward the injection hole 11 in the axial direction. By adjusting the fixed position of the adjusting member 62, the initial load of the coil spring 61 pressing the valve body 20 against the seat surface 124 is adjusted.

The movable core 30 is a member that is engaged with the rear end portion 21 of the valve body 20 and moves together with the valve body 20 in the axial direction Da. The movable core 30 is separate from the valve body 20 and has a through hole (valve body insertion hole) 31 through which the valve body 20 is inserted in the axial direction at the center in the radial direction. Further, the movable core 30 has an eccentric through hole 32 at a position eccentric from the valve body insertion hole 31 which penetrates in the axial direction Da to form a fuel flow path FC. The movable core 30 is movably inserted into the nozzle body 10.

The base end side end of the small coil spring 63 is in contact with the lower end surface of the movable core 30, and the movable core 30 is urged toward the fixed core 40.

The housing 70 has a bottomed cylindrical shape, and the nozzle body 10 is inserted into a bottom through hole 71 provided in the center of the bottom. The housing 70 is fixed to the nozzle body 10 by welding between the opening edge of the bottom through hole 71 and the outer peripheral surface of the nozzle body 10, for example, over the entire circumference. The housing 70 is arranged so as to surround the distal end side of the fixed core 40, the coil bobbin 51, and the outer circumference of the coil 50. The inner peripheral surface of the housing 70 forms an outer peripheral yoke portion facing the large diameter portion 14 of the nozzle body 10 and the coil 50 via the resin portion 80.

The resin portion 80 is filled between the fixed core 40, the coil bobbin 51 and the coil 50, and the housing 70, and the fixed core 40 of the fuel injection device 1 on the rear end side (base end side) of the housing 70. It is molded so as to cover the outer peripheral surface excluding the rear end portion and form a connector 81 having a terminal 811 for power supply. With the above configuration, a toroidal magnetic passage including a fixed core 40, a movable core 30, a nozzle body 10, and a housing 70 is formed around the coil 50.

Hereinafter, the operation of the fuel injection device 1 according to the present embodiment will be described.

In the fuel injection device 1, the terminal 811 of the connector 81 is connected to the connection terminal of a plug (not shown) and connected to a high-voltage power supply or a battery power supply, and the coil 50 is energized by an engine control unit (ECU) (not shown). Be controlled. The elastic force of the coil spring 61 for urging the valve body 20 toward the seat surface 124 at the tip of the nozzle body 10 is larger than the elastic force for the small coil spring 63 for urging the movable core 30 toward the fixed core 40. big. Therefore, when the coil 50 is not energized, the spherical portion 230 (the seat portion 232) of the tip portion 23 of the valve body 20 is pressed against the seat surface 124 of the injection hole forming member 12, and the flow path leading to the injection hole 11. The FC is closed and the valve is closed (see FIG. 1).

When the coil 50 is energized by the ECU, magnetic flux flows through the magnetic circuit including the fixed core 40, the movable core 30, the nozzle body 10, and the housing 70, and a magnetic attraction force that attracts the movable core 30 is generated in the fixed core 40. .. When the magnetic attraction force of the fixed core 40 exceeds the set load of the coil spring 61, the movable core 30 moves toward the fixed core 40. The movable core 30 moves until the end face facing the fixed core 40 (that is, the rear end face or the proximal end face) collides with the distal end face of the fixed core 40. At this time, the movable core 30 is engaged with the rear end portion 21 of the valve body 20 to move the valve body 20 toward the fixed core 40 in the valve opening direction.

When the valve body 20 moves toward the fixed core 40 in the valve opening direction, the seat portion 230 of the valve body 20 is separated from the seat portion 124a and reaches the injection hole 11 between the valve body 20 and the seat surface 124. The road FC is opened and the injection hole 11 is opened to open the valve. In the fuel injection device 1, when the valve body 20 is in such a valve opening position (valve opening state), the fuel supplied from the opening 43 at the rear end of the fixed core 40 via the filter 90 is fixed. It flows along the axial direction toward the tip end side of the nozzle body 10 through the through hole 42 of the core 40. As a result, the fuel is injected into the combustion chamber of the internal combustion engine through the injection holes 11.

When the energization of the coil 50 is interrupted by the ECU, the magnetic flux flowing through the magnetic circuit disappears, and the magnetic attraction force of the fixed core 40 that attracts the movable core 30 disappears. Then, due to the difference between the elastic force (urging force) of the coil spring 61 and the elastic force (urging force) of the small coil spring 63, the valve body 20 is directed toward the seat surface 124 together with the movable core 30 that engages with the rear end portion 21. The seat portion 230 of the valve body 20 comes into contact with the seat portion 124a. As a result, the flow path FC between the valve body 20 and the seat surface 124 is closed, the injection hole 11 is closed by the valve body 20, and the fuel injection through the injection hole 11 is stopped. NS.

The valve body 20 has an engaging portion 213 at the rear end portion 21 of the valve body 20 in order to engage with the movable core 30 when the on-off valve operates.

Next, the form of the housing 70 will be described in detail with reference to FIGS. 2, 3, and 4.

FIG. 2 is an enlarged cross-sectional view showing the periphery of the housing and coil of FIG. 1 in an enlarged manner. FIG. 3 is an enlarged cross-sectional view showing the vicinity of the rectangular shape portion formed on the inner peripheral surface of the housing of FIG. 2 in an enlarged manner.

As described above, the fuel injection device 1 of the present embodiment includes a movable core 30, a fixed core 40 having a small diameter portion 40b located on the side of the movable core 30, and a fixed core 40 and a movable core 30 when energized. A coil 50 that generates a magnetic attraction force between the two, a housing 70 that is located on the radial outside of the coil 50 and houses the coil 50, and a resin member that is filled inside the housing 70 in the radial direction and covers the coil 50. Resin part) 80 and.

The fixed core 40 is located on the side opposite to the side of the movable core 30 with respect to the small diameter portion 40b, and has a large diameter portion 40a having a larger outer diameter than the small diameter portion 21. That is, in the vertical direction of the fuel injection device 1 in the axial direction Da, the side where the fixed core 40 is arranged is the upper side and the side where the movable core 30 is arranged is the lower side in the arrangement of the fixed core 40 and the movable core 30. In this case, the fixed core 40 is located above the small diameter portion 40b.

The large diameter portion 40a is formed as a flange portion that projects outward in the radial direction from the outer peripheral surface 40ba of the small diameter portion 40b. That is, the flange portion 40a is formed as a large-diameter portion having an outer peripheral surface aa having an outer diameter larger than the outer diameter of the outer peripheral surface 40ba. It has a side end surface (lower end surface, lower end of the large diameter portion 40a) 40ac. A recessed portion (stepped cylindrical portion) 40bb recessed inward in the radial direction is formed at the lower end portion of the outer peripheral surface 40ba, and the recessed portion 40bb is press-fitted into the inner peripheral surface 10a of the upper end portion of the nozzle body 10.

In the housing 70, an inner peripheral surface 70a is formed on the upper end side, an inner peripheral surface 70b having a diameter smaller than that of the inner peripheral surface 70a is formed on the lower side of the inner peripheral surface 70a, and the inner peripheral surface 70a and the inner peripheral surface 70b are formed. A stepped surface 70c is formed between them. That is, the inner diameter of the inner peripheral surface 70a is larger than the inner diameter of the inner peripheral surface 70b. When the fixed core 40 is press-fitted into the nozzle body 10, the stepped surface 70c comes into contact with the lower end surface 40ac of the large diameter portion 40a, and the relative position between the fixed core 40 and the nozzle body 10 is determined.

The housing 70 is formed with a recessed portion 250 that is recessed outward in the radial direction on the inner peripheral surface 70a thereof. In this embodiment, three recesses 250-1, 250-2, 250-3 are formed. That is, the housing 70 has a second recessed portion 250-2 formed so as to be recessed outward in the radial direction on the inner peripheral surface 70a, and the second recessed portion 250-2 is the first recessed portion 250-1. It is formed on the upper side, and at least the upper end is formed so as to be located on the upper side with respect to the upper end (upper end surface) 40ab of the large diameter portion 40a in the axial direction Da. Further, the housing 70 has a third recessed portion 250-3 formed so as to be recessed outward in the radial direction on the inner peripheral surface 70a, and the third recessed portion 250-3 is the second recessed portion 250-2. It is formed on the upper side.

Each recess 250 is formed by a bottom surface 250a and side surfaces 250b and 250c. The bottom surface 250a is formed as a surface along the inner peripheral surface 70a, and the side surfaces 250b and 250c are formed as surfaces along the radial direction. The side surface 250b is a side surface located on the distal end side (lower side) in the axial direction, and the side surface 250c is a side surface located on the proximal end side (upper side) in the axial direction.

In this case, the lower side surface 250b and the upper side surface 250c of the recessed portion 250-1 are such that the lower side surface 250b is located on the side of the center line 40AX with respect to the upper end surface 40ab and the upper side surface 250c is on the lower side in the axial direction. It is arranged so as to be located on the side away from the center line 40AX with respect to the side surface 250b.

In this embodiment, in the cross section parallel to the central axis AX1 and including the central axis AX1, the cross section of the recessed portion 250 is formed in a rectangular shape, so that the lower side surface 250b is the lower end (tip side end) of the recessed portion 250. The upper side surface 250c coincides with the upper end (base end side end portion) of the recessed portion 250. That is, the first recessed portion 250-1 is formed so that the cross-sectional shape seen from the circumferential direction is rectangular, and the lower end 250b forming the lowermost end of the recessed portion 250-1 is the lower side of the first recessed portion 250-1. The upper end 250c, which is composed of side surfaces and forms the uppermost end of the recessed portion 250-1, is composed of the upper side surface of the first recessed portion 250-1.

The recessed portion (first recessed portion) 250-1 is formed at a position overlapping the outer peripheral surface 40aa of the large diameter portion 40a in the axial direction Da. That is, the housing 70 is radially outward at a position (inside the overlapping range) of the inner peripheral surface 70a facing the outer peripheral surface 40aa of the large diameter portion 40a and overlapping the outer peripheral surface 40aa in the axial direction Da. It has a recessed portion 250-1 formed so as to be recessed.

The lower side surface 250b of the recessed portion 250-1 is arranged so as to be located on the upper end surface 40ab side with respect to the center line 40AX passing through the center of the large diameter portion 40a in the axial direction, and the upper side surface of the recessed portion 250-1. The 250c is arranged so as to be located on the lower end surface 40ac side with respect to the upper end surface 40ab of the large diameter portion 40a.

That is, in the vertical direction of the fuel injection device 1 in the axial direction Da, the side where the fixed core 40 is arranged is the upper side and the side where the movable core 30 is arranged is the lower side in the arrangement of the fixed core 40 and the movable core 30. In this case, the lowermost end (lower side surface) 250b of the recessed portion 250-1 is located above the center 40AX of the large diameter portion 40a in the axial direction Da, and the uppermost end (upper side surface) of the recessed portion 250-1. The 250c is located below the upper end (upper end surface) 40ab of the large diameter portion 40aa in the axial direction Da.

In other words, the housing 70 has a plurality of recessed portions 250-1, 250-2, 250-3 formed so as to be recessed outward in the radial direction on the inner peripheral surface 70a, and the plurality of recessed portions 250-1. , 250-2, 250-3, the lowermost portion 250-1 of the recessed portion 250-1 is located above the center 40AX of the large diameter portion 40a in the axial direction Da, and the uppermost end 250c is located. It is located below the upper end 40ab of the large diameter portion 40a in the axial direction Da.

In this embodiment, the recessed portion 250-1 having the uppermost end (upper side surface) 250c formed on the lower side with respect to the upper end surface 40ab of the large diameter portion 40a has the lower end 250b forming the lowermost end and the uppermost end 250c. It is composed of one first recess having an upper end 250c and the upper end 250c.

In this embodiment, the inner circumference of the housing 70 located between the recesses 250-1, 250-2, 250-3 is formed by forming the three recesses 250-1, 250-2, 250-3. Convex portions 251-1,251-2, 251-3 are formed in which the surface 70a is convex inward in the radial direction from the bottom surface 250a of the recessed portions 250-1, 250-2, 250-3. In this case, when the bottom surfaces 250a of the recessed portions 250-1, 250-2, and 250-3 are viewed as one inner peripheral surface, the convex portion 251-1 which is convex inward in the radial direction from the inner peripheral surface 250a. , 251-2, 251-3 will be formed.

That is, the housing 70 has the first recessed portion 250-1, the second recessed portion 250-2, and the third recessed portion 250-3, so that the housing 70 has the first recessed portion 250-1, the second recessed portion 2, and the third recessed portion 250-. It has a plurality of convex portions 251-1,251-2,251-3 which are formed so as to protrude inward in the radial direction from the bottom surface 250a of 3 and whose cross-sectional shape is rectangular when viewed from the circumferential direction. The portions 251-1,251-2,251-3 are formed side by side along the axial direction Da.

In this embodiment, a minute gap δ larger than 0 and 0.08 mm or less is formed between the inner peripheral surface 70a of the housing 70 in which the recessed portion 250 is formed and the outer peripheral surface 40aa of the large diameter portion 40a. Hereinafter, δ is used as a code for expressing the minute gap and also as a code for expressing the size (dimension) of the minute gap.

The gap dimension δ between the inner peripheral surface 70a of the housing 70 on which the recessed portions 250-1, 250-2, 250-3 are formed and the outer peripheral surface 40aa of the large diameter portion 40a is the recessed portion 250-1,250-. It is smaller than the depth dimension d and the width dimension w of 2,250-3. In other words, the radial depth d of the recessed portion 250 and the width w of the axial direction Da are minute gaps between the inner peripheral surface 70a of the housing 70 (the top of the convex portion 251) and the outer peripheral surface 40a of the large diameter portion 40a. It is formed to a size larger than δ.

In this embodiment, a plurality of convex portions 250 that are convex inward in the radial direction on the inner peripheral surface of the housing 70 (bottom surface 250a of the recessed portion 250) and have a rectangular shape in the cross-sectional view including the central axis are arranged in the axial direction. It will be formed. In this embodiment, the three recessed portions 250-1, 250-2, and 250-3 make the three convex portions 251-1 (first convex portion), 251-2 (second convex portion), and 251-3 ( The third convex portion) is formed. The number of the recessed portions 250 is not limited to three, and only one recessed portion 250-1 may be provided, or at least a plurality of recessed portions 250 including the recessed portion 250-1 may be provided. It may be a configuration.

The configuration and dimensions described as the recessed portion 250 are commonly provided in the three recessed portions 250-1, 250-2, 250-3. Further, in the present embodiment, since the number of the recessed portions 250 is not limited to three, the entire plurality of recessed portions may be described as the recessed portions 250.

In this embodiment, the second recessed portion 250-2 recessed outward in the radial direction on the inner peripheral surface 70a of the housing 70 is the first recessed portion on the side opposite to the lower end surface 40ac of the large diameter portion 40a with respect to the center line 40AX. It is formed on the side away from the center line 40AX with respect to 250-1. In this embodiment, the lower side surface 250b of the second recessed portion 250-2 is formed at substantially the same position in the axial direction as the upper end surface 40ab of the large diameter portion 40a. In this case, the lower side surface 250b of the second recessed portion 250-2 has a dimension (w / 2) of 1/2 the width w of the recessed portion 250 in the axial direction with respect to the upper end surface 40ab of the large diameter portion 40a. ) Should be located within the range. That is, the lower end 250b of the second recess 250-2 is half the distance w between the upper end 250c and the lower end 250b of the second recess 250-2 with respect to the upper end 40ab of the large diameter portion 40a in the axial direction Da. It may be formed so as to be located at a distance shorter than (w / 2).

Further, the third recessed portion 250-3 recessed outward in the radial direction on the inner peripheral surface 70a of the housing 70 is formed on the second recessed portion 250-2 on the side opposite to the lower end surface 40ac of the large diameter portion 40a with respect to the center line 40AX. On the other hand, it is formed on the side away from the center line 40AX.

The recessed portion 250 is formed in an annular shape over the entire circumference of the inner peripheral surface 70a of the housing 70.

With the above configuration, it is possible to suppress the influence on the basic characteristics and improve the waterproof performance of the coil part. Hereinafter, this action and effect will be described.

The lower side surface 250b of the recessed portion 250-1 is arranged so as to be located on the upper end surface 40ab side with respect to the center line 40AX passing through the center of the large diameter portion 40a in the axial direction, so that the magnetic circuit of the coil 50 is formed. The recessed portion 250 can be arranged in a small range that does not affect the dented portion 250. That is, the recess 250 is not arranged on the lower end surface 40ac side with respect to the center line 40AX where the magnetic flux is concentrated. In such a configuration, since the recessed portion 250 is not arranged in the vicinity of the main magnetic field line 55 where the coil 50 is generated, the influence on the basic characteristics of the fuel injection device 1 is suppressed, and the recessed portion 250 is waterproof. It has the effect of improving performance.

Further, by providing the second recessed portion 250-2 on the upstream side of the first recessed portion 250-1 and the third recessed portion 250-3 on the upstream side of the second recessed portion 250-2, the housing 70 can be provided. The distance between the boundary surface between the housing 70 and the resin portion 80 from the upper end portion to the coil portion 50 can be long, and the longer the distance, the more difficult it is for water to penetrate to the outer peripheral surface of the coil 50.

FIG. 4 is a radial enlarged cross-sectional view (IV-IV cross-sectional view) around the housing and coil of FIG. FIG. 5 is a diagram for explaining the flow of the resin in the vicinity of the rectangular shape portion. The arrows Ar1, Ar2, Ar3, and Ar4 in FIG. 5 indicate the resin flow.

The lower side surface 250b of the second recessed portion 250-2 is formed at substantially the same position in the axial direction as the upper end surface 40ab of the large diameter portion 40a, so that the resin flow indicated by the arrow Ar1 can be formed, and the housing can be formed. It becomes easy to form the resin portion 80 in the minute gap δ between the inner peripheral surface 70a of the 70 and the outer peripheral surface 40aa of the large diameter portion 40a of the fixed core 40.

Further, by arranging the first recessed portion 250-1 at a position overlapping with the outer peripheral surface 40aa of the large diameter portion 40a in the axial direction, the resin is provided with a clearance 45 between the coil 50 and the housing 70 (see FIG. 4). Then, it can flow through the first recessed portion 250-1 to the clearance 46 between the fixed core 40 and the housing 70. Alternatively, the resin can flow from the clearance 46 to the clearance 45 through the first recess 250-1. At this time, as shown by arrows Ar2 and Ar3, the resin flows into the minute gap δ between the clearance 45 and the clearance 46, and the effect of facilitating the formation of the resin portion 80 in the minute gap δ can also be obtained.

FIG. 6 is a diagram illustrating shrinkage of the resin in the vicinity of the rectangular shape portion.

By arranging a minute gap of 0.08 mm or less between the inner peripheral surface 70a of the housing 70 and the outer peripheral surface 40a of the large diameter portion 40a of the fixed core 40, the gap size in the radial direction can be reduced, and the resin can be reduced. The volume can be reduced. Generally, the volume of the resin in the resin portion 80 shrinks due to cooling or thermal deterioration after injection molding. For example, in the case of a polyamide material, the volume shrinks by about 1%. Therefore, by reducing the resin volume of the minute gap δ between the inner peripheral surface 70a of the housing 70 and the outer peripheral surface 40a of the large diameter portion 40a of the fixed core 40, the amount of volume shrinkage can be reduced accordingly. Can be done. The smaller the shrinkage amount of the resin, the smaller the gap formed between the resin 80 and the inner peripheral surface 70a of the housing 70, and the more difficult it is for water to enter.

In FIG. 6, due to the shrinkage of the resin in the resin portion 80 of the minute gap δ, a gap δ1 is formed between the resin portion 80 and the tip surface of the first convex portion 251-1, and the upper side of the first recessed portion 250-1. A gap δ2 is formed between the side surface 250c and the bottom surface 250a of the first recess 250-1, and a gap δ3 is formed between the first recessed portion 250-1 and the bottom surface 250a. In this case, the size of the gap δ1 can be made smaller than the sizes of the gap δ2 and the gap δ3. Therefore, the effect of suppressing the invasion of water in the gap δ1 is enhanced.

Further, the recessed portion 250 is provided so that the cross-sectional shape seen from the circumferential direction is rectangular. Since the resin portion 80 shrinks as described above, the resin portion 80 of the recessed portion 250 shrinks in the axial direction of the fuel injection device 1. Therefore, the resin portion 80 contacts the upper side surface 250c or the lower side surface 250b of the recessed portion 250 by generating surface pressure, so that the contact portion between the resin portion 80 and the upper side surface 250c or the lower side surface 250b has a waterproof effect. Can be improved. Further, since the recessed portion 250 is formed on the entire circumference of the inner peripheral surface 70a of the housing 70, it is possible to prevent the infiltration of water on the entire circumference of the inner peripheral surface 70a. In FIG. 6, the resin portion 80 is described as being in contact with the lower side surface 250b of the recessed portion 250 and forming a gap δ2 between the resin portion 80 and the upper side surface 250c.

The fuel injection device of this embodiment described above has the following features.

(1) A movable core 30, a fixed core 40 having a small diameter portion 40b located on the side of the movable core 30, and a coil 50 that generates a magnetic attraction force between the fixed core 40 and the movable core 30 when energized. A fuel injection device 1 comprising a housing 70 located on the radial outer side of the coil 50 and accommodating the coil 50, and a resin member 80 filled on the radial inner side of the housing 70 and covering the coil 50. ,
When the vertical direction in the axial direction Da of the fuel injection device 1 is the side where the fixed core 40 is arranged is the upper side and the side where the movable core 30 is arranged is the lower side in the arrangement of the fixed core 40 and the movable core 30. ,
The fixed core 40 has a large diameter portion 40a that is located above the small diameter portion 40b and has an outer diameter larger than that of the small diameter portion 40b.
The housing 70 is recessed outward in the radial direction at a position (inside the overlapping range) of the inner peripheral surface 70a facing the outer peripheral surface 40aa of the large diameter portion 40a and overlapping the outer peripheral surface 40aa in the axial direction Da. It has a recessed portion 250-1 formed so as to be sewn, and has a recessed portion 250-1.
The lowermost end 250b of the recessed portion 250-1 is located above the center 40AX of the large diameter portion 40a in the axial direction Da.
The uppermost end 250c of the recessed portion 250-1 is located below the upper end (upper end surface) 40ab of the large diameter portion 40aa in the axial direction Da.

(2) In (1)
The recessed portion 250-1 is composed of one first recessed portion having a lower end 250b forming the lowermost end and an upper end 250c forming the uppermost end 250c.

(3) In (2)
The first recessed portion 250-1 is formed so that the cross-sectional shape seen from the circumferential direction is rectangular.
The lower end 250b forming the lowermost end of the recessed portion 250-1 is formed by the lower side surface of the first recessed portion 250-1.
The upper end 250c forming the uppermost end of the recessed portion 250-1 is formed by the upper side surface of the first recessed portion 250-1.

(4) In (2)
The housing 70 has a second recessed portion 250-2 formed on the inner peripheral surface 70a so as to be recessed outward in the radial direction.
The second recessed portion 250-2 is formed on the upper side of the first recessed portion 250-1, and is formed so that at least the upper end is located above the upper end (upper end surface) 40ab of the large diameter portion 40a in the axial direction Da. Will be done.

(5) In (4)
The lower end 250b of the second recess 250-2 is half the distance w between the upper end 250c and the lower end 250b of the second recess 250-2 with respect to the upper end 40ab of the large diameter portion 40a in the axial direction Da. It is formed so as to be located at a distance shorter than w / 2).

(6) In (4)
The housing 70 has a third recessed portion 250-3 formed so as to be recessed outward in the radial direction on the inner peripheral surface 70a.
The third recess 250-3 is formed on the upper side of the second recess 250-2.

(7) In (6)
The housing 70 has a first recessed portion 250-1, a second recessed portion 250-2, and a third recessed portion 250-3, so that the housing 70 has a first recessed portion 250-1, a second recessed portion 2, and a third recessed portion 250-3. It has a plurality of convex portions 251-1,251-2,251-3, which are formed so as to protrude inward in the radial direction from the bottom surface 250a of the above and have a rectangular cross-sectional shape when viewed from the circumferential direction.
The convex portions 251-1,251-2,251-3 are formed side by side along the axial direction Da.

(8) In (1)
The radial depth d of the recessed portion 250 is formed to be larger than the gap dimension δ between the inner peripheral surface 70a of the housing 70 and the outer peripheral surface 40aa of the large diameter portion 40a.

(9) In (1)
The recess 250 is formed in an annular shape over the entire circumference of the inner peripheral surface 70a of the housing 70.

(10) In (1)
A minute gap δ of 0.08 mm or less is formed between the inner peripheral surface 70a of the housing 70 in which the recessed portion 250 is formed and the outer peripheral surface 40aa of the large diameter portion 40a.

(11) The movable core 30, the fixed core 40 having a small diameter portion 40b located on the side of the movable core 30, and the coil 50 that generates a magnetic attraction force between the fixed core 40 and the movable core 30 when energized. A fuel injection device 1 comprising a housing 70 located on the radial outer side of the coil 50 and accommodating the coil 50, and a resin member 80 filled on the radial inner side of the housing 70 and covering the coil 50. ,
When the vertical direction in the axial direction Da of the fuel injection device 1 is the side where the fixed core 40 is arranged is the upper side and the side where the movable core 30 is arranged is the lower side in the arrangement of the fixed core 40 and the movable core 30. ,
The fixed core 40 has a large diameter portion 40a that is located above the small diameter portion 40b and has an outer diameter larger than that of the small diameter portion 40b.
The housing 70 has a plurality of recessed portions 250-1, 250-2, 250-3 formed so as to be recessed outward in the radial direction on the inner peripheral surface 70a.
Of the plurality of recessed portions 250-1, 250-2, 250-3, the recessed portion 250-1 formed at the lowermost portion has the lowermost lower end 250b upward with respect to the center 40AX of the large diameter portion 40a in the axial direction Da. The uppermost end 250c is located below the upper end 40ab of the large diameter portion 40a in the axial direction Da.

(12) In (11)
The gap dimension δ between the inner peripheral surface 70a of the housing 70 on which the recessed portions 250-1, 250-2, 250-3 are formed and the outer peripheral surface 40aa of the large diameter portion 40a is the recessed portion 250-1,250-. It is smaller than the depth dimension d and the width dimension w of 2,250-3.

According to the fuel injection device 1 of the present embodiment described above, it is possible to suppress the influence on the basic characteristics of the fuel injection device 1 and improve the waterproof performance of the coil portion 50.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and even if there is a design change or the like within a range that does not deviate from the gist of the present invention. , They are included in the present invention.

Further, the present invention is not limited to the above-described embodiment, and includes various modified forms. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations.

1 ... Fuel injection device, 30 ... Movable core, 40 ... Fixed core, 40a ... Large diameter part, 40aa ... Outer peripheral surface of large diameter part 40a, 40ab ... Upper end (upper end surface) of large diameter part 40aa, 40AX ... Large diameter part 40a central axis (center of axis direction Da), 40b ... small diameter part, 50 ... coil, 70 ... housing, 70a ... inner peripheral surface of housing 70, 80 ... resin part (resin member), 250 ... recessed part, 250- 1 ... 1st recess, 250-2 ... 2nd recess, 250-3 ... 3rd recess, 250a ... bottom surface of recess, 250b ... lower end (lower side surface) of recess 250, 250c ... recess 250 Upper end (upper side surface), 251-1,251-2,251-3 ... Convex portion, d ... Radial depth of recessed portion 250, Da ... Axial direction, w ... Upper end 250c and lower end 250b of recessed portion 250 Distance between, δ ... The clearance dimension between the inner peripheral surface 70a of the housing 70 and the outer peripheral surface 40aa of the large diameter portion 40a.

Claims (12)

A movable core, a fixed core having a small diameter portion located on the side of the movable core, a coil that generates a magnetic attraction between the fixed core and the movable core when energized, and a coil in the radial direction of the coil. A fuel injection device including a housing located on the outside and accommodating the coil, and a resin member filled inside the housing in the radial direction and covering the coil.
When the vertical direction in the axial direction of the fuel injection device is such that the side where the fixed core is arranged is the upper side and the side where the movable core is arranged is the lower side in the arrangement of the fixed core and the movable core.
The fixed core is located above the small diameter portion and has a large diameter portion having a larger outer diameter than the small diameter portion.
The housing has a recessed portion formed so as to be recessed outward in the radial direction at a position overlapping the outer peripheral surface in the axial direction on the inner peripheral surface facing the outer peripheral surface of the large diameter portion.
The lowermost end of the recess is located above the center of the large diameter portion in the axial direction.
The uppermost end of the recessed portion is a fuel injection device located below the upper end of the large diameter portion in the axial direction. In the fuel injection device according to claim 1,
The recessed portion is a fuel injection device including one first recessed portion having a lower end forming the lowermost end and an upper end forming the uppermost end. In the fuel injection device according to claim 2.
The first recess is formed so that the cross-sectional shape seen from the circumferential direction is rectangular.
The lower end forming the lowermost end of the recessed portion is formed by a lower side surface of the first recessed portion.
The upper end forming the uppermost end of the recessed portion is a fuel injection device composed of an upper side surface of the first recessed portion. In the fuel injection device according to claim 2.
The housing has a second recess formed on the inner peripheral surface so as to be recessed outward in the radial direction.
The second recessed portion is a fuel injection device formed above the first recessed portion so that at least the upper end thereof is located above the upper end portion of the large diameter portion in the axial direction. In the fuel injection device according to claim 4,
The lower end of the second recess is formed so as to be located at a distance shorter than half of the distance between the upper end and the lower end of the second recess with respect to the upper end of the large diameter portion in the axial direction. Fuel injection device. In the fuel injection device according to claim 4,
The housing has a third recess formed on the inner peripheral surface so as to be recessed outward in the radial direction.
The third recess is a fuel injection device formed on the upper side of the second recess. In the fuel injection device according to claim 6,
The housing protrudes inward in the radial direction from the bottom surface of the first recessed portion, the second recessed portion, and the third recessed portion by the first recessed portion, the second recessed portion, and the third recessed portion. It has a plurality of convex portions having a rectangular cross-sectional shape when viewed from the circumferential direction.
The convex portions are fuel injection devices formed side by side along the axial direction. In the fuel injection device according to claim 1,
A fuel injection device in which the radial depth of the recessed portion is formed to be larger than the clearance dimension between the inner peripheral surface of the housing and the outer peripheral surface of the large diameter portion. In the fuel injection device according to claim 1,
The recessed portion is a fuel injection device formed in an annular shape over the entire circumference of the inner peripheral surface of the housing. In the fuel injection device according to claim 1,
A fuel injection device in which a minute gap of 0.08 mm or less is formed between the inner peripheral surface of the housing in which the recessed portion is formed and the outer peripheral surface of the large diameter portion. A movable core, a fixed core having a small diameter portion located on the side of the movable core, a coil that generates a magnetic attraction between the fixed core and the movable core when energized, and a coil in the radial direction of the coil. A fuel injection device including a housing located on the outside and accommodating the coil, and a resin member filled inside the housing in the radial direction and covering the coil.
When the vertical direction in the axial direction of the fuel injection device is such that the side where the fixed core is arranged is the upper side and the side where the movable core is arranged is the lower side in the arrangement of the fixed core and the movable core.
The fixed core is located above the small diameter portion and has a large diameter portion having a larger outer diameter than the small diameter portion.
The housing has a plurality of recesses formed on the inner peripheral surface so as to be recessed outward in the radial direction.
The lowermost portion of the recessed portion formed at the lowermost portion of the plurality of recessed portions is located above the center of the large diameter portion in the axial direction, and the uppermost end is located at the upper end of the large diameter portion in the axial direction. A fuel injection device located on the lower side. In the fuel injection device according to claim 11,
A fuel injection device in which the clearance dimension between the inner peripheral surface of the housing in which the recessed portion is formed and the outer peripheral surface of the large diameter portion is smaller than the depth dimension and the width dimension of the recessed portion.

Images