WO2017043211A1

WO2017043211A1 - Fuel injection device

Info

Publication number: WO2017043211A1
Application number: PCT/JP2016/072256
Authority: WO
Inventors: 威生三宅; 清隆小倉; 真士菅谷; 貴敏飯塚
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2015-09-11
Filing date: 2016-07-29
Publication date: 2017-03-16
Also published as: JPWO2017043211A1

Abstract

Provided is a fuel injection device wherein strength capable of withstanding high fuel pressure can be ensured. A fuel injection device is provided with: a needle valve 114A (valve body); a mover 102 for driving the needle valve 114A; and a stationary core 107 (stator) disposed facing the mover 102. The fuel injection device is further provided with an adapter 140 (pipe) which is constituted by a separate member from the stationary core 107, is disposed upstream of the stationary core 107, and is used to mount the fuel injection device to an external device. The stationary core 107 and the adapter 140 are directly affixed to each other by press fitting.

Description

Fuel injection device

The present invention relates to a fuel injection device.

As an example of the prior art, in a fuel injection valve (fuel injection device), a technique in which a fuel connector is welded so as to communicate with a hollow portion of a hollow disc portion of a core is known (for example, FIG. 6). The core side of the connector pipe has a structure with an expanded end surface so that a sufficient welding allowance can be obtained. This welding is performed over the entire circumference of the joint boundary by laser welding or the like in order to maintain fuel sealability. The fuel connector pipe has a step inside the fuel filter that removes dust and the like mixed in the fuel from the upstream side of the fuel passage and a spring presser that defines the initial load of the return spring. It is. A fuel injection valve that can form such a step at a low cost by pipe drawing is disclosed.

∙ The fuel connector pipe can be changed to various fuel joint structures by being configured separately from the core.

As an example of another conventional technique, in a fuel injection valve, a technique is known in which a fuel introduction pipe is provided with flanges at an upper end and a lower end, and a flange on the lower end side is welded to an upper surface of a flange of a fixed core (for example, , See FIG. 1 of Patent Document 2). This fixed core is made of magnetic stainless steel, and the fuel introduction pipe is formed of a non-magnetic metal member, and the lower part thereof is narrowed by pressing, and a C-ring pin having a C-shaped cross section is formed on the inner periphery of the lower part. Is press-fitted. The load of the return spring is adjusted by adjusting the press-fitting amount of the pin. A fuel filter is attached to the upper end of the fuel introduction pipe. It is disclosed that the fuel introduction pipe and the fixed core are welded in advance.

The fuel passage assembly is configured by integrally joining a fuel introduction pipe, a fixed core, and a nozzle holder by welding. In this way, only the fixed core that should be the main magnetic circuit is made relatively thick to secure the magnetic path, and the fuel introduction pipe is not made a magnetic path, so the non-magnetic pipe is made thin and thin. In addition, the nozzle holder can be thinned, and each element of the fuel passage assembly can be set to a reasonable specification according to the respective needs. Then, mass production can be performed at low cost by pressing each element of the fuel passage assembly described above.

Japanese Patent Laid-Open No. 2002-130085 Japanese Patent Laid-Open No. 2002-130071

In the fuel injection valve of any of the embodiments described in Patent Documents 1 and 2, a component called a connector pipe or a fuel introduction pipe (hereinafter referred to as an adapter in the present specification) is a separate member from the fixed core, Although it is described that welding is performed, there is no description about the strength that can withstand high fuel pressure and the idea of maintaining the same axis as the fixed core.

In recent exhaust gas regulations, it is necessary to reduce the amount and quantity of particulate matter contained in exhaust gas, and even in fuel injection valves that use gasoline, the maximum fuel pressure for regular use may increase to about 35 MP. . When the normal maximum fuel pressure is 35 MPa, the fuel injection valve is required to operate up to 45 MPa, for example.

Then, a greater stress than that in the conventional case may be generated in the adapter pipe due to the fuel pressure, and the margin for strength may be reduced.

An object of the present invention is to provide a fuel injection device capable of ensuring a strength capable of withstanding a high fuel pressure.

In order to achieve the above object, the present invention provides a fuel injection apparatus comprising: a valve body; a mover that drives the valve body; and a stator that is disposed so as to face the mover. It is composed of a member separate from the stator, and is provided on the upstream side of the stator, and includes a pipe for attaching the fuel injection device to an external device, and the stator and the pipe are directly fixed by press-fitting. The

According to the present invention, the strength capable of withstanding high fuel pressure can be ensured. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

1 is a partial cross-sectional view of a fuel injection device and a fuel pipe according to a first embodiment of the present invention. It is another sectional drawing of a part of fuel injection apparatus and fuel piping by a 1st embodiment of the present invention. It is the graph which showed the relationship between the fuel piping internal diameter and the load by fuel pressure. It is a whole sectional view of a fuel injection device by a comparative example. It is sectional drawing of the component of the fuel-injection apparatus by the 1st Embodiment of this invention. It is an expanded sectional view of the fuel-injection apparatus by the 2nd Embodiment of this invention. It is an expanded sectional view of the fuel injection valve by the modification of the 2nd Embodiment of this invention.

Hereinafter, the configuration and operational effects of the fuel injection valves (fuel injection devices) according to the first and second embodiments of the present invention will be described with reference to the drawings. In the drawings, the size of the parts and the size of the gap may be exaggerated from the actual ratio to make the function easy to understand, and unnecessary parts may be omitted to explain the function. is there. In each embodiment, the same constituent elements are given the same reference numerals, and redundant descriptions are omitted.

(First embodiment)
First, the outline of the configuration of the fuel injection valve according to the first embodiment of the present invention will be described with reference to FIGS. 1A and 1B. 1A and 1B are longitudinal sectional views of a fuel injection valve according to a first embodiment of the present invention.

The internal combustion engine is provided with a fuel injection control device (not shown) that performs an operation of converting an appropriate fuel amount corresponding to an operating state into an injection time of the fuel injection valve and drives a fuel injection valve that supplies fuel. Yes.

As shown in FIG. 1A, in the fuel injection valve, for example, the movable part 114 includes a cylindrical movable element 102 and a needle valve 114A (valve element) located at the center of the movable element 102. Yes. A gap is provided between the end surface of the fixed core 107 (stator) having a fuel introduction hole for introducing fuel to the center and the end surface of the mover 102. An electromagnetic coil 105 (solenoid) for supplying magnetic flux to the magnetic path including the gap is provided. In other words, the fixed core 107 (stator) is arranged to face the mover 102 as shown in FIG. 1A.

The mover 102 is driven by the magnetic attraction generated between the end face of the mover 102 and the end face of the fixed core 107 by the magnetic flux passing through the gap to drive the mover 102, and the needle valve 114A is The fuel passage provided in the valve seat portion 39 is opened by being separated from the seat portion 39 (valve seat). In other words, the mover 102 drives the needle valve 114A (valve element).

The amount of fuel to be injected is mainly determined by the pressure difference between the fuel pressure and the atmospheric pressure at the injection port of the fuel injection valve, and the time during which the fuel is injected while maintaining the needle valve 114A open. .

When energization of the electromagnetic coil 105 is stopped, the magnetic attractive force acting on the mover 102 disappears, the force of the elastic member that urges the needle valve 114A in the closing direction, and the fuel flowing between the needle valve 114A and the fixed core 107. The needle valve 114A and the mover 102 move in the closing direction due to a pressure drop caused by the flow velocity of the valve, and the needle valve 114A is seated on the valve seat portion 39 to close the fuel passage. The fuel is sealed by the contact between the needle valve 114A and the valve seat portion 39, and the fuel is prevented from leaking from the fuel injection valve at an unintended timing.

In recent years, from the viewpoint of reducing fuel consumption, attempts have been made to reduce the amount of fuel consumed when a vehicle is mounted by reducing the displacement of an internal combustion engine in combination with a supercharger and using a heat-efficient operating region. Yes. This attempt is particularly effective when combined with an in-cylinder direct injection internal combustion engine that is expected to improve the intake air filling amount by vaporizing the fuel and to improve the knock resistance.

In addition, since a large reduction in fuel consumption is required in a wide range of vehicles, demand for in-cylinder direct injection internal combustion engines increases, while other devices that are effective in reducing fuel consumption, such as recovery of regenerative energy, are used in automobiles. It is necessary to mount on. Moreover, cost reduction of various devices is calculated | required from a viewpoint of reducing total cost, and the cost reduction request | requirement to the fuel injection valve for in-cylinder direct injection is also rising similarly.

On the other hand, it is also required to further reduce the components contained in the exhaust gas of the internal combustion engine. In particular, from the viewpoint of reducing the amount and quantity of particulate matter, the fuel injection pressure is reduced from the conventional 20 MPa to about 35 MPa, for example. Attempts have been made to reduce the droplet diameter of the injected fuel and promote vaporization.

When the fuel pressure is increased, the load applied in the axial direction increases in proportion to the fuel pipe 211 and the fuel passage area of the fuel injection valve. Therefore, in order to achieve a fuel injection valve that can withstand a high fuel pressure, it is necessary to reduce the axial load by reducing the diameter of the fuel passage at the connection with the fuel pipe 211.

Similarly, when the fuel pressure is increased, the stress generated in the member that holds the internal fuel pressure with respect to the outside of the fuel injection valve increases. In order to provide a margin of strength against stress generated at high fuel pressure, it is necessary to increase the thickness to ensure rigidity or to use a material having high strength.

However, as described above, in order to reduce the load applied in the axial direction, the needle valve 114A and the spring are provided inside the fuel injection valve while reducing the axial load by reducing the diameter of the fuel passage at the connection portion with the fuel pipe 211. 110, it is difficult to increase the wall thickness because it is necessary to secure an inner diameter in which the adjuster 54 can be accommodated. In order to maintain a margin for strength even at high stress, it is effective to select a material with high yield stress and tensile strength.

Since the fixed core 107 of the fuel injection valve constitutes a part of an electromagnetic solenoid, a material having excellent magnetic characteristics is used. Since materials having excellent magnetic properties generally have low yield stress and tensile strength, they are unsuitable for use in the connecting portion with the fuel pipe 211 where the wall thickness is small and high rigidity is required as described above.

Although details will be described later, the fuel injection valve of the present embodiment divides the fixed core, which has been conventionally integrated, into two parts, an adapter 140 and a fixed core 107, and the adapter 140 has yield stress and tensile strength from the fixed core 107. The fixed core 107 is made of a material having excellent magnetic properties, and after two parts are press-fitted in the radial direction, they are fixed by welding all around.

Therefore, a fuel injection valve that does not deteriorate the magnetic characteristics of the fixed core 107 while reducing the axial load by reducing the fuel passage diameter at the connection portion with the fuel pipe 211 in response to an increase in fuel pressure. , And can be manufactured with reduced cost.

In other words, the adapter 140 (pipe) is composed of a member separate from the fixed core 107 (stator), and is disposed on the upstream side of the fixed core 107 to attach the fuel injection device to an external device (such as a common rail). It is a part of. Here, the fixed core 107 and the adapter 140 are directly fixed by press-fitting.

As a result, the adapter 140 (pipe) is separated from the fixed core 107 (stator), so that it can be assembled by changing only the adapter 140 when dealing with various shapes of external devices (common rails, etc.). It is possible and the manufacturing cost can be reduced. In addition, by directly press-fitting the fixed core 107 into the adapter 140 without any other parts, the number of parts can be reduced and manufacturing can be performed at low cost.

(Configuration details)
Next, the configuration of the fuel injection valve according to the first embodiment of the present invention will be described in detail with reference to FIGS. 1A to 4.

1A, the injection hole cup support 101 includes a small-diameter cylindrical portion 22 having a small diameter and a large-diameter cylindrical portion 23 having a large diameter. An injection hole cup 116 (fuel injection hole forming member) having a guide part 115 and a fuel injection hole 117 is inserted or press-fitted into the distal end portion of the small diameter cylindrical part 22, and the outer periphery of the front end surface of the injection hole cup 116 is inserted. The edge is welded all around. Thereby, the nozzle hole cup 116 is fixed to the small diameter cylindrical portion 22. The guide part 115 has a function of guiding the outer periphery when the valve body tip part 114B provided at the tip of the needle valve 114A constituting the movable part 114 moves up and down in the axial direction of the fuel injection valve.

In the nozzle hole cup 116, a conical valve seat portion 39 is formed on the downstream side of the guide portion 115. A valve body tip 114B provided at the tip of the needle valve 114A abuts on or separates from the valve seat sheet 39, thereby blocking the flow of fuel or guiding it to the fuel injection hole. A groove is formed on the outer periphery of the nozzle hole cup support 101, and a combustion gas seal member typified by a resin-made chip seal 131 is fitted into the groove.

A needle valve guide portion 113 (needle valve guide member) for guiding the needle valve 114A constituting the mover is provided at the inner peripheral lower end portion of the fixed core 107. The needle valve 114A is provided with a guide portion 127. Although not shown, the guide portion 127 is partially provided with a chamfered portion to form a fuel passage. The elongated needle valve 114A has a radial position defined by the needle valve guide 113 and is guided to reciprocate straight in the axial direction. Note that the valve opening direction is an upward direction of the valve shaft, and the valve closing direction is a downward direction of the valve shaft direction.

A head 114C having a stepped portion 129 having an outer diameter larger than the diameter of the needle valve 114A is provided at the end opposite to the end where the valve body tip 114B of the needle valve 114A is provided. The upper surface of the stepped portion 129 is provided with a seating surface for the spring 110 that urges the needle valve 114A in the valve closing direction, and holds the spring 110 together with the head portion 114C.

The mover portion 114 has a mover 102 provided with a through hole 128 through which the needle valve 114A passes. A zero spring 112 that biases the movable element 102 in the valve opening direction is held between the movable element 102 and the needle valve guide portion 113.

Since the diameter of the through hole 128 is smaller than the diameter of the stepped portion 129 of the head portion 114C, under the biasing force of the spring 110 or the action of gravity that presses the needle valve 114A toward the valve seat of the nozzle hole cup 116. The upper surface of the movable element 102 held by the zero spring 112 is in contact with the lower end surface of the stepped portion 129 of the needle valve 114A, and both are engaged.

As a result, the two cooperate in response to the upward movement of the mover 102 against the urging force or gravity of the zero spring 112 or the downward movement of the needle valve 114A along the urging force of the zero spring 112 or gravity. It will move. However, when the force for moving the needle valve 114A upward or the force for moving the mover 102 downward acts independently of each other regardless of the biasing force or gravity of the zero spring 112, they may move in different directions. it can.

The fixed core 107 is press-fitted into the inner peripheral portion of the large-diameter cylindrical portion 23 of the nozzle hole cup support 101 and is welded and joined at the press-fit contact position. A gap formed between the inside of the large-diameter cylindrical portion 23 of the nozzle hole cup support 101 and the outside air is sealed by this welding joint. In the center of the fixed core 107, a through hole 107D having a diameter φCn is provided as a fuel introduction passage.

In other words, the adapter 140 and the fixed core are press-fitted by direct contact between the lower surface (downstream surface) of the adapter 140 (pipe) and the upper surface (upstream surface) of the fixed core 107 (stator). 107 is fixed.

In some cases, the lower end surface of the fixed core 107, the upper end surface of the movable element 102, and the collision end surface are plated to improve durability. Even when relatively soft soft magnetic stainless steel is used for the mover 102, durability reliability can be ensured by using hard chromium plating or electroless nickel plating.

The lower end of the initial load setting spring 110 is in contact with the spring receiving surface formed on the upper end surface of the stepped portion 129 provided on the head portion 114C of the needle valve 114A, and the other end of the spring 110 is the adjuster. Received at 54. As a result, the spring 110 is held between the head 114 </ b> C and the adjuster 54. By adjusting the fixing position of the adjuster 54, the initial load by which the spring 110 presses the needle valve 114A against the valve seat portion 39 can be adjusted.

A cup-shaped housing 103 is fixed to the outer periphery of the large-diameter cylindrical portion 23 of the nozzle hole cup support 101. A through hole is provided at the center of the bottom of the housing 103, and the large-diameter cylindrical portion 23 of the nozzle hole cup support 101 is inserted through the through hole. A portion of the outer peripheral wall of the housing 103 forms an outer peripheral yoke portion facing the outer peripheral surface of the large-diameter cylindrical portion 23 of the nozzle hole cup support 101.

An electromagnetic coil 105 wound in an annular shape is disposed in a cylindrical space formed by the housing 103. The electromagnetic coil 105 is formed by an annular coil bobbin 104 having a U-shaped groove that opens outward in the radial direction, and a copper wire wound in the groove. A rigid conductor 109 is fixed at the start and end of winding of the electromagnetic coil 105 and is drawn out from a through hole provided in the fixed core 107.

The conductor 109, the fixed core 107, and the outer periphery of the large-diameter cylindrical portion 23 of the nozzle hole cup support 101 are molded by injecting insulating resin from the inner periphery of the upper end opening of the housing 103 and covered with the resin molded body 121. Is called. Thus, a toroidal magnetic path is formed around the electromagnetic coils (104, 105).

A plug for supplying power from a high-voltage power source and a battery power source is connected to the connector 43A formed at the tip of the conductor 109, and energization and de-energization are controlled by a controller (not shown). While the electromagnetic coil 105 is energized, a magnetic attractive force is generated between the movable element 102 of the movable element 114 and the fixed core 107 in the magnetic attractive gap by the magnetic flux passing through the magnetic circuit 140 </ b> M, and the movable element 102 sets the spring 110. It moves upward by being sucked with a force exceeding the load.

At this time, the mover 102 engages with the needle valve head 114C, moves upward together with the needle valve 114A, and moves until the upper end surface of the mover 102 collides with the lower end surface of the fixed core 107. As a result, the valve body front end portion 114B at the front end of the needle valve 114A is separated from the valve seat portion 39, and the fuel passes through the fuel passage and is ejected from the fuel injection hole 117 at the front end of the injection hole cup 116 into the combustion chamber of the internal combustion engine. To do.

While the valve body front end portion 114B at the front end of the needle valve 114A is separated from the valve seat portion 39 and pulled upward, the elongate needle valve 114A has a needle valve guide portion 113 and a guide portion for the injection hole cup 116. It is guided by the two portions 115 so as to return straight along the valve shaft direction.

When the energization of the electromagnetic coil 105 is cut off, the magnetic flux disappears and the magnetic attractive force in the magnetic attractive gap also disappears. In this state, the spring force of the initial load setting spring 110 that pushes the head portion 114C of the needle valve 114A in the opposite direction overcomes the force of the zero spring 112, so that the entire movable element portion 114 (movable element 102, needle valve 114A) is obtained. Works. As a result, the movable element 102 is pushed back by the spring force of the spring 110 to the valve closing position where the valve body tip portion 114B contacts the valve seat portion 39.

While the valve body tip 114B at the tip of the needle valve 114A contacts the valve seat portion 39 and is in the valve closing position, the elongated needle valve 114A is guided only by the needle valve guide 113, and the injection hole cup 116 It is not in contact with the guide part 115.

At this time, the stepped portion 129 of the head portion 114C comes into contact with the upper surface of the movable element 102 and moves the movable element 102 to the needle valve guide section 113 side by overcoming the force of the zero spring 112. When the valve body front end portion 114B collides with the valve seat portion 39, the mover 102 is separate from the needle valve 114A, and therefore continues to move in the direction of the needle valve guide portion 113 due to inertial force. At this time, friction due to fluid is generated between the outer periphery of the needle valve 114A and the inner periphery of the mover 102, and the energy of the needle valve 114A that rebounds from the valve seat sheet portion 39 in the valve opening direction again is absorbed.

Since the movable element 102 having a large inertial mass is separated from the needle valve 114A, the rebound energy itself is reduced. Further, since the inertial force of the movable element 102 that has absorbed the rebound energy of the needle valve 114A is reduced by that amount and the repulsive force received after the zero spring 112 is compressed is also reduced, the needle valve is caused by the rebounding phenomenon of the movable element 102 itself. The phenomenon that 114A is moved again in the valve opening direction is less likely to occur. Thus, the rebound of the needle valve 114A is minimized, and the so-called secondary injection phenomenon in which the valve is opened after the energization of the electromagnetic coil 105 is cut off and the fuel is injected randomly is suppressed.

1A schematically shows the load applied in the axial direction of the fuel injection valve by the fuel pressure. Since the fuel injection valve is connected to the fuel pipe 211 and the fuel is sealed by the O-ring 212, the fuel pipe interior 213 and the fuel injection valve are filled with high-pressure fuel. The fuel pipe sectional area is determined by the fuel pipe inner diameter φR, and the product of the fuel pipe sectional area and the fuel pressure is defined as a fuel pressure load.

Since the fuel pipe 211 is fixed to an engine (not shown), the fuel injection valve receives a fuel pressure load in the direction of the arrow 214. For example, the fuel injection valve is in contact with the engine (not shown) through the tapered surface 215 of the housing 103, so that the above-described fuel injection valve is connected via the adapter 140, the fixed core 107, the injection hole cup support 101, and the housing 103. The fuel pressure load is transmitted.

FIG. 2 is a graph in which the fuel pressure is calculated with respect to the fuel pipe inner diameter φR and the fuel pressure. Conventionally, the fuel pipe inner diameter φR is, for example, φ13.2 (mm, hereinafter omitted), the maximum fuel pressure is, for example, 20 MPa, and the fuel pressure load at that time is approximately 2700 N. If the fuel pressure is set to 35 MPa while the fuel pipe inner diameter φR is set to φ13.2, the fuel pressure load is about 4700 N. As described above, since the fuel pressure load is transmitted to the components constituting the fuel injection valve, the stress generated in each component increases as the fuel pressure increases. If the shape and material of the parts constituting the fuel injection valve are not changed, the strength margin is reduced. On the other hand, using a material with high strength leads to an increase in cost.

If the fuel pipe inner diameter φR is, for example, φ9.4, the fuel pressure load can be suppressed to approximately 2400 N even at a fuel pressure of 35 MPa. Therefore, the fuel injection valve can be configured without using a material having a strength higher than that of the conventional fuel injection valve.

FIG. 3 shows a cross-sectional view of a fuel injection valve according to a comparative example. The fixed core 407 has an integral structure up to the O-ring mounting portion 450. When the fuel pipe inner diameter φR used when the fuel pressure is 20 MPa is φ13.2, even when the inner diameter φCo of the fixed core 407 through which the spring 410 and the regulator 452 can pass is set, the thickness of the fixed core 407 is thin. A sufficient thickness can be secured in the

portions

450 and 451. Therefore, although the material used for the fixed core 407 is excellent in magnetism, sufficient rigidity and strength can be ensured even when a material having a relatively small material strength is used.

On the other hand, when the fuel pressure is larger than the conventional one, for example, 35 MPa, it is necessary to reduce the fuel pressure load by setting the fuel pipe inner diameter φR to φ9.4, for example, as shown in FIG. Even when the fuel pipe inner diameter φR shown in FIG. 1A is set to φ9.4, for example, the adapter inner diameter φCn needs to be secured to about φ4.4 in order to pass the regulator 54 and the spring 110 during the assembly process of the fuel injection valve. There is. Therefore, a portion where the thickness cannot be sufficiently increased, such as the O-ring mounting portion 250, is generated. If the O-ring mounting portion 250 is selected with priority given to magnetism in the same manner as the material used for the fixed core 107, there is a possibility that sufficient rigidity and strength cannot be ensured.

FIG. 4 is a sectional view of only the adapter 140 and the fixed core 107 constituting the fuel injection valve according to the first embodiment of the present invention. Since the thickness of the O-ring mounting portion 250 is small for the adapter 140, a material giving priority to strength is selected. Because of the selected material giving priority to strength, it can withstand the stress generated at a fuel pressure of 35 MPa. Since the fixed core 107 constitutes a magnetic circuit, there is no thin portion. Therefore, a material having excellent magnetism is selected for the fixed core 107. Since the wall thickness is large, even when a material with low strength is selected, it can withstand the stress generated at a fuel pressure of 35 MPa.

In other words, the saturation magnetic flux density of the fixed core 107 (stator) is composed of a member separate from the fixed core 107 and is directly fixed to the fixed core 107 by press-fitting. Bigger than. Thereby, for example, the manufacturing cost of the adapter 140 can be reduced while ensuring the magnetic characteristics of the fixed core 107.

Here, the tensile strength of the fixed core 107 (stator) is higher than the tensile strength of the adapter 140 (pipe) that is formed of a member separate from the fixed core 107 and is directly fixed to the fixed core 107 by press-fitting. small. Thereby, for example, even if the shape of the fixed core 107 becomes complicated, the strength of the adapter 140 can be secured and the processing can be easily performed.

The mounting portion 501 of the adapter 140 of the fuel injection valve and the mounting portion 502 of the fixed core 107 are contacted in the radial direction, press-fitted, and welded all around at 503 to seal the fuel. Since the attachment part 501 of the adapter 140 and the attachment part 502 part of the fixed core 107 are press-fitted and fixed before welding, the adapter 140 can be prevented from falling due to strain generated during welding.

In other words, the fixed core 107 (stator) has a mounting portion 502 (stator side mounting portion) on the upstream side, and the adapter 140 (pipe) has a mounting portion 501 (pipe side mounting portion) on the downstream side. The attachment portion 502 and the attachment portion 501 are press-fitted in direct contact with each other in the radial direction. Accordingly, the mounting portion 502 and the mounting portion 501 can be easily manufactured, and the mounting portion 502 and the mounting portion 501 can be press-fitted and fixed.

Further, the downstream end 501a of the attachment portion 501 (pipe side attachment portion) comes into contact with the upper surface (upstream surface) of the attachment portion 502 (stator side attachment portion), and butt welding is performed at this contact portion. . Specifically, the mounting portion 501 (pipe side mounting portion) is positioned on the outer peripheral side of the mounting portion 502 (stator side mounting portion), and the downstream end 501a of the mounting portion 501 contacts the fixed core 107 in the axial direction. Then, butt welding is performed at the contact portion.

This makes it possible to butt-weld the attachment portion 502 and the attachment portion 501, and to manufacture and fix both of them inexpensively and firmly. Since the material used for the adapter 140 is stronger than the fixed core 107, it makes sense to arrange it on the outer peripheral side where stress is high. A material with high strength can be made thin and easy to weld.

Here, the fixed core 107 (stator) is formed with a protruding portion 107a (collar portion) protruding outward from the mounting portion 502 (stator side mounting portion), and the protruding portion 107a and the fixed core 107 are formed. And an integral member. The fixed core 107 is formed by cold forging. Thereby, even if there exists the protrusion part 107a, it becomes possible to reduce a waste of material and to manufacture cheaply.

In detail, for example, stainless steel such as K-M35 is used for the fixed core 107. This K-M35 has low hardness and can be manufactured by cold forging. Therefore, it can manufacture easily by manufacturing by cold forging including the protrusion part 107a, and it becomes possible to reduce cost.

It should be noted that if a harder material that cannot be used for cold forging is adopted for the fixed core 107, it is necessary to cut it out by machining including the protruding portion 107a (the collar portion). This is a waste of members and has a great cost demerit. Although it is conceivable to weld the protrusion 107a separately, this leads to difficulty in positioning and an increase in production cost due to welding.

Incidentally, the projecting portion 107a (rib portion) forms a good magnetic path between the projecting portion 107a and the end portion (upper end) of the housing 103 opposite to the projecting portion 107a, thereby reliably configuring the magnetic circuit 140M (see FIG. 1A). can do.

As shown in FIG. 1B, when the fuel injection valve is connected to the fuel pipe 211 via the plate 251, the fixed core 107 is pulled downstream with respect to the adapter 140 due to the fuel pressure load caused by the fuel pressure inside the fuel injection valve. . Therefore, the butt weld 503 is welded so as to have a strength that can withstand the fuel pressure load. Butt welding has higher joint efficiency than lap welding performed with conventional fuel injection valves, and strength is improved for the same penetration amount.

As described above, even when the fuel pipe inner diameter φR is reduced as the fuel pressure increases, the conventional fixed core is divided into the adapter 140 and the fixed core 107, and an appropriate material is selected and combined by welding after press-fitting. Can achieve the necessary functions.

According to this embodiment, it is possible to ensure the strength that can withstand high fuel pressure. Further, since the butt welding is performed after the fixed core 107 and the adapter 140 are fixed by press-fitting, it is easy to keep the adapter 140 and the fixed core 107 coaxial.

(Second Embodiment)
FIG. 5 shows an example of the structure of the adapter 140 and the fixed core 107 included in the fuel injection valve according to the second embodiment of the present invention.

This embodiment is different from the first embodiment in that the mounting portion 502 of the fixed core 107 is disposed outside the mounting portion 501 of the adapter 140. That is, in the first embodiment, the fixed core 107 is press-fitted (inserted) into the adapter 140 as shown in FIG. 1A, whereas in the second embodiment, the adapter 140 is fixed as shown in FIG. Press fit into the core 107.

The outer diameter portion (outer periphery) of the attachment portion 501 of the adapter 140 and the inner diameter portion (inner periphery) of the attachment portion 502 of the fixed core 107 are press-fitted, and the entire circumference is butt welded at 503 parts.

Here, the radial size D2 of the mounting portion 502 (stator side mounting portion) is larger than the radial size D1 of the mounting portion 501 (pipe side mounting portion).

Since the fixed core 107 (stator) is a main part of the magnetic circuit, how to make its shape greatly affects the magnetic characteristics of the magnetic circuit. For this reason, the shape of the fixed core 107 may be somewhat complicated. In this case, it is necessary to use a material that can be easily processed. Then, since the strength of the material of the fixed core 107 is weak, securing the strength when assembling becomes a problem.

In this respect, by adopting the configuration of the present embodiment, even when the adapter 140 is press-fitted into the fixed core 107, the strength in assembling is ensured by increasing (thickening) the radial size D1 of the mounting portion 501. It becomes possible to do.

(Modification)
FIG. 6 shows a modification of the structure of the adapter 140 and the fixed core 107 included in the fuel injection valve according to the second embodiment of the present invention.

As in FIG. 5, the outer diameter portion (outer periphery) of the attachment portion 501 of the adapter 140 and the inner diameter portion (inner periphery) of the attachment portion 502 of the fixed core 107 are press-fitted, and the entire circumference is butt welded at 503 parts.

In this modification, the attachment portion 501 of the adapter 140 is extended to the downstream side of the adjuster 54, and the fixed core 107 has a minimum size necessary for the magnetic circuit. Since a material with good magnetic properties has a high price per unit mass, the cost can be reduced by making the fixed core 107 small.

As the needle valve 114A moves up and down, the spring 110 also moves up and down, but the inner diameter φAn of the adapter 140 is made smaller than the inner diameter φB of the fixed core 107 so that the movement is not hindered. Also, the outlet corner 601 of the inner diameter φAn of the adapter 140 and the inlet 602 of the inner diameter φB of the fixed core 107 are tapered or rounded so that the movement of the spring 110 is not hindered.

Note that the present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to the one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

The embodiment of the present invention may be the following aspect.

(1) A valve body that sits on or separates from the valve seat part, a spring member that biases the valve body toward the valve seat part, a mover that drives the valve body, and a movable element that faces the mover In a fuel injection device comprising a stator that is formed, a member separate from the stator, and disposed on the upstream side of the stator, and having an attachment portion (adapter 140) for attaching the fuel injection device to an external device, A fuel injection device, wherein a stator-side small-diameter portion (attachment portion 502) and an attachment-portion-side small diameter portion (attachment portion 501) are in contact with each other in a radial direction and are press-fitted and butt welded.

(2) In the fuel injection valve according to (1), the attachment portion (adapter 140) has an attachment portion-side small-diameter portion (attachment portion 501) configured with the first radial thickness in the downstream portion, and is fixed. The fuel injection device, wherein the child has a stator-side small-diameter portion (attachment portion 502) having a second radial thickness larger than the first radial thickness on the upstream side.

22 ... Small diameter cylindrical portion 23 of the injection hole cup support ... Large diameter cylindrical portion 39 of the injection hole cup support ... Valve seat portion (seat portion of the seat member)
43A ... Connector 101 ... Injection hole cup support 102 ... Movable element 103 ... Housing 104 ... Coil bobbin 105 ... Electromagnetic coil (solenoid)
107: Fixed core (stator)
107D ... Stator through hole (fuel passage)
109 ... conductor 110 ... spring 112 ... zero spring 113 ... needle valve guide (shoulder)
114 ... Movable part 114A ... Needle valve 114B ... Valve body tip 114C ... Head of needle valve (protrusion for spring guide)
DESCRIPTION OF SYMBOLS 115 ... Guide part 116 ... Injection hole cup 117 ... Fuel injection hole 121 ... Resin molding 126 ... Fuel passage 127 ... Guide part 128 ... Through-hole 136 ... Gap 140 ... Adapter (pipe)
201 ... Guided portion 202 at the tip of the valve body ... Guide portion 203 of the nozzle hole cup ... Valve body sheet portion 301 at the tip of the valve body ... Shaft 302 of the nozzle hole ... Shaft 303 of the valve body ... Center of spherical diameter 401 ... Injection hole Upstream part 402 of cup: Clearance

Claims

The disc,
A mover for driving the valve body;
In a fuel injection device comprising: a stator arranged to face the mover;
It is composed of a member separate from the stator, and is disposed on the upstream side of the stator, and includes a pipe for attaching the fuel injection device to an external device,
The fuel injection device, wherein the stator and the pipe are directly fixed by press-fitting.
The fuel injection device according to claim 1,
The fuel injection device, wherein the downstream surface of the pipe and the upstream surface of the stator are directly contacted to be fixed by press-fitting.
The fuel injection device according to claim 1,
The stator has a stator side mounting portion on the upstream side, and the pipe has a pipe side mounting portion on the downstream side,
The fuel injection device, wherein the stator side mounting portion and the pipe side mounting portion are directly contacted and press-fitted in a radial direction.
The fuel injection device according to claim 3, wherein
The fuel injection device according to claim 1, wherein a downstream tip portion of the pipe-side attachment portion contacts an upstream surface of the stator-side attachment portion, and butt welding is performed at the contact portion.
The fuel injection device according to claim 3 or 4,
The fuel injection device, wherein a radial size of the stator side mounting portion is configured to be larger than a radial size of the pipe side mounting portion.
The fuel injection device according to claim 3, wherein
The pipe-side attachment portion is positioned on the outer peripheral side of the stator-side attachment portion, and the downstream end portion of the pipe-side attachment portion contacts the stator in the axial direction and is butt welded at the contact portion. A fuel injection device characterized by the above.
The fuel injection device according to claim 1 or 2,
A fuel injection device characterized in that a saturation magnetic flux density of the stator is made of a member separate from the stator and is larger than a saturation magnetic flux density of the pipe fixed directly to the stator by press-fitting. .
The fuel injection device according to claim 1 or 2,
The fuel injection device according to claim 1, wherein the tensile strength of the stator is made of a member separate from the stator, and is smaller than the tensile strength of the pipe that is directly fixed to the stator by press-fitting.
The fuel injection device according to claim 1,
The fuel injection device according to claim 1, wherein the stator is formed with a protruding portion that protrudes toward the outer peripheral side downstream of the stator side mounting portion, and is formed of a member that is integral with the protruding portion and the stator.
The fuel injection device according to claim 9, wherein
The fuel injection device according to claim 1, wherein the stator is formed by cold forging.