WO2018079361A1

WO2018079361A1 - Fuel injection device

Info

Publication number: WO2018079361A1
Application number: PCT/JP2017/037628
Authority: WO
Inventors: 真士菅谷; 明靖宮本; 清隆小倉; 威生三宅; 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: 2016-10-31
Filing date: 2017-10-18
Publication date: 2018-05-03
Also published as: JPWO2018079361A1; JP6800238B2

Abstract

The purpose of the present invention is to provide a structure that facilitates stabilization of injection quantity even when injection intervals become shorter in a fuel injection device which is able to shorten the time that a valve element takes to move a distance necessary to open a nozzle hole upon receipt of an impact force from a movable iron core during valve opening. In order to achieve this purpose, the fuel injection device according to the present invention is provided with: a valve element that opens and closes a flow channel; a movable iron core that moves the valve element in a valve-opening direction by means of magnetic attraction; an intermediate member that is configured to form a preliminary stroke gap (g1) between the movable iron core and the valve element in a closed valve state; a spring for the movable iron core for biasing the movable iron core in a valve opening direction; and a spring for the intermediate member for biasing the intermediate member in a valve closing direction, wherein the spring forces of the spring for the movable iron core and the spring for the intermediate member are configured such that the movement distance of the intermediate member when the iron core impinges on the intermediate member after the valve element is closed is less than the preliminary stroke gap (g1).

Description

Fuel injection device

The present invention relates to a fuel injection device that is used in an internal combustion engine and mainly injects fuel.

As background art in this technical field, there is JP 2011-137442 A (Patent Document 1). In this publication, in the fuel injection nozzle, an intermediate member is provided which slides with both the movable iron core and the valve body and forms a gap in the displacement direction between the movable iron core and the valve body in the closed state. As a result, the movable iron core collides with the valve body when the valve is opened, so the travel time for the distance necessary to open the nozzle hole can be shortened, and the movable iron core and the valve can move relative to each other after the on-off valve. Controllability is improved.

JP 2011-137442 A

Acceleration of atomization of spray and stabilization of injection amount are required for fuel injection devices. The cause of the deterioration of spray atomization is that the fuel flow rate becomes slow during the low lift period when the valve element starts to open. The deterioration factor of the injection amount stabilization is that the convergence of the valve operation after the valve opening is slow. Therefore, it is necessary for the fuel injection device to make the opening of the valve steep and at the same time to quickly converge the operation of the valve body after the valve is opened. In Patent Document 1, by providing a gap in the displacement direction between the movable iron core and the valve body, only the movable iron core is operated before energization is started, and the impact force at the time of the collision is applied to the valve body when the valve is opened. And by providing an intermediate member between the valve bodies of the movable iron core, the relative movement of the valve body and the movable iron core is enabled, and the injection amount can be stabilized.

However, after the valve is closed, the intermediate member continues to be displaced in the valve closing direction, and when injection is performed until the valve returns to the valve closing standby state, a state in which the gap in the displacement direction is small occurs and opens. There was a problem that valve behavior was not stable.

Accordingly, an object of the present invention is to provide a fuel injection device capable of reducing the low lift period when the valve element receives an impact force from the movable iron core when the valve is opened, so that the opening can be performed even when the injection interval is shortened. An object of the present invention is to provide a structure that improves the stability of the operation of the valve body during the valve operation and promotes the stabilization of the injection amount.

In order to achieve the above object, the fuel injection device of the present invention includes a valve body that opens and closes a flow path, a movable iron core that moves the valve body in a valve opening direction by a magnetic attractive force, and the movable iron core in a valve-closed state. An intermediate member configured to form a preliminary stroke gap (g1) between the valve body and the valve body, a movable core spring for biasing the movable core in the valve opening direction, and the intermediate member in the valve closing direction. An intermediate member spring that biases the intermediate member, and when the movable iron core collides with the intermediate member after the valve body is closed, the moving distance of the intermediate member is less than the preliminary stroke gap (g1). The spring force of the movable iron core spring and the intermediate member spring was set.

According to the configuration of the present invention, it is possible to reduce the amount of displacement of the intermediate member during the valve closing operation and suppress the period during which the preliminary stroke gap becomes small, and promote the stabilization of the fuel injection amount. Other configurations, operations, and effects of the present invention will be described in detail in the following examples.

It is sectional drawing which shows the structure of the fuel-injection apparatus which concerns on 1st Example of this invention, and is a longitudinal cross-sectional view which shows a cut surface parallel to the center axis line 100a. It is sectional drawing which expands and shows the electromagnetic drive part of the fuel-injection apparatus shown in FIG. It is a figure explaining operation | movement of the movable part at the time of setting the spring force corresponding to the injection command pulse in the Example of this invention. It is a figure explaining operation | movement of the movable part when the spring force corresponding to the injection command pulse in the Example of this invention is not set. It is sectional drawing which shows the structure of the fuel-injection apparatus which concerns on 2nd Example of this invention, and is a longitudinal cross-sectional view which shows a cut surface parallel to the center axis line 100a.

Hereinafter, examples according to the present invention will be described.

The configuration of the fuel injection device 100 according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view showing a structure of a fuel injection device according to one embodiment of the present invention, and is a longitudinal sectional view showing a cut surface parallel to a central axis 100a. FIG. 2 is an enlarged cross-sectional view of the electromagnetic drive unit 400 shown in FIG. FIG. 3 is a diagram for explaining the operation of the movable iron core 404. FIGS. 3 (a) and 4 (a) show the ON / OFF state of the injection command pulse, and FIGS. 3 (b) and 4 (b) show the movable iron core 404 with the valve closed state of the plunger rod 102 being zero displacement. The displacement of the intermediate member 414 is shown. In addition, the operation | movement from t0 to t6 of the movable iron core 404 shown in FIG.3 (b) and FIG.4 (b) and the intermediate member 414 is the same.

The fuel injection device 100 includes a fuel supply unit 200 that supplies fuel, a nozzle unit 300 that is provided with a valve unit 300a that allows or blocks fuel flow, and an electromagnetic drive unit that drives the valve unit 300a. 400. In the present embodiment, an electromagnetic fuel injection device for an internal combustion engine using gasoline as fuel will be described as an example. In addition, the fuel supply part 200, the valve part 300a, the nozzle part 300, and the electromagnetic drive part 400 have indicated the applicable part with respect to the cross section described in FIG. 1, and do not show a single component.

In the fuel injection device 100 of the present embodiment, a fuel supply unit 200 is configured on the upper end side of the drawing, a nozzle unit 300 is configured on the lower end side, and an electromagnetic drive unit 400 is configured between the fuel supply unit 200 and the nozzle unit 300. ing. That is, the fuel supply unit 200, the electromagnetic drive unit 400, and the nozzle unit 300 are arranged in this order along the direction of the central axis 100a.

The end of the fuel supply unit 200 opposite to the nozzle unit 300 is connected to a fuel pipe (not shown). The nozzle part 300 has an end opposite to the fuel supply part 200 in a mounting hole (insertion hole) formed in a not-shown intake pipe or a combustion chamber forming member (cylinder block, cylinder head, etc.) of the internal combustion engine. Inserted. The electromagnetic fuel injection device 100 is supplied with fuel from a fuel pipe through a fuel supply unit 200 and injects fuel from the tip of the nozzle unit 300 into the intake pipe or the combustion chamber. Inside the fuel injection device 100, a fuel passage 101 is provided so that fuel flows substantially along the direction of the central axis 100 a of the electromagnetic fuel injection device 100 from the end of the fuel supply unit 200 to the tip of the nozzle unit 300. (101a to 101f) are configured.

In the following description, the end portion or the end portion side of the fuel supply unit 200 positioned on the opposite side to the nozzle portion 300 is the base end portion or the base end at both ends in the direction along the central axis 100a of the fuel injection device 100. The end side or the end side of the nozzle part 300 located on the opposite side to the fuel supply unit 200 will be referred to as the end side or the front end side. In addition, with reference to the vertical direction in FIG. 1, the description will be given with “upper” or “lower” attached to each part constituting the electromagnetic fuel injection device.
This is done for ease of explanation, and the mounting form of the electromagnetic fuel injection device for the internal combustion engine is not limited to the vertical direction.

(Configuration explanation)
Hereinafter, the configuration of the fuel supply unit 200, the electromagnetic drive unit 400, and the nozzle unit 300 will be described in detail.

The fuel supply unit 200 includes a fuel pipe 201. A fuel supply port 201a is provided at one end (upper end) of the fuel pipe 201, and a fuel passage 101a is formed inside the fuel pipe 201 so as to penetrate in the direction along the central axis 100a. The other end (lower end) of the fuel pipe 201 is joined to one end (upper end) of the fixed iron core 401.

An O-ring 202 and a backup ring 203 are provided on the outer peripheral side of the upper end portion of the fuel pipe 201.
The O-ring 202 functions as a seal that prevents fuel leakage when the fuel supply port 201a is attached to the fuel pipe. The backup ring 203 is for backing up the O-ring 202. The backup ring 203 may be configured by laminating a plurality of ring-shaped members. Inside the fuel supply port 201a, a filter 204 that filters out foreign matters mixed in the fuel is disposed.
The nozzle part 300 includes a nozzle body 300b, and a valve part 300a is formed at the tip (lower end) of the nozzle body 300b. The nozzle body 300b is a hollow cylindrical body and constitutes a fuel passage 101f on the upstream side of the valve portion 300a. In addition, a movable iron core receiving portion 311 is formed in the lower fuel passage portion 101 e of the electromagnetic drive portion 400. Note that a tip seal 103 is provided on the outer peripheral surface of the tip of the nozzle body 300b to maintain airtightness when mounted on the internal combustion engine.

The valve portion 300 a includes an injection hole forming member 301, a guide member 302, and a valve body 303 provided at one end portion (lower end side tip portion) of the plunger rod 102.
The injection hole forming member 301 includes a valve seat 301a that contacts the valve body 303 and seals fuel, and a fuel injection hole 301b that injects fuel. The injection hole forming member 301 is inserted and fixed in a concave inner peripheral surface 300ba formed at the tip of the nozzle body 300b. At this time, the outer periphery of the front end surface of the injection hole forming member 301 and the inner periphery of the front end surface of the nozzle body 300b are welded to seal the fuel.

The guide portion 302 is on the inner peripheral side of the injection hole forming member 301 and constitutes a guide surface on the distal end side (lower end side) of the plunger rod 102, and the movement of the plunger rod 102 in the direction along the central axis 100a (open / close valve direction). To guide you.

The electromagnetic drive unit 400 includes a fixed iron core 401, a coil 402, a housing 403, a movable iron core 404, an intermediate member 414, a plunger cap 410, a first spring member 405, a third spring member 406, and a second. And a spring member 407. The fixed iron core 401 is also called a fixed core. The movable iron core 404 is called a movable core, a movable element or an armature.

The fixed iron core 401 has a fuel passage 101c and a joint 401a with the fuel pipe 201 at the center. The outer peripheral surface 401b of the fixed core 401 is fitted and joined to the large-diameter inner peripheral portion 300c of the nozzle body 300b, and the outer peripheral surface 401e having a larger diameter than the outer peripheral surface 401b is fitted and joined to the outer peripheral side fixed core 401d. Yes. A coil 402 is wound around the outer periphery of the fixed iron core 401 and the large-diameter portion 300c of the cylindrical member.

The housing 403 is provided so as to surround the outer peripheral side of the coil 402 and constitutes the outer periphery of the electromagnetic fuel injection device 100. The upper end side inner peripheral surface 403a of the housing 403 is connected to the outer peripheral surface 401f of the outer peripheral side fixed iron core 401d joined to the outer peripheral surface 401e of the fixed iron core 401.

A movable iron core 404 is disposed on the lower end surface 401 g side of the fixed iron core 401. The upper end surface 404c of the movable iron core 404 is opposed to the lower end surface 401g of the fixed iron core 401 with a gap g2 in the closed state. The outer peripheral surface of the movable iron core 404 is opposed to the inner peripheral surface of the large diameter portion 300c of the nozzle body 300b with a slight gap, and the movable iron core 404 is centered on the inner side of the large diameter portion 300c of the cylindrical member. It is provided so as to be movable in a direction along 100a.

A magnetic path is formed so that the magnetic flux circulates around the fixed iron core 401, the movable iron core 404, the housing 403, and the large-diameter portion 300c of the cylindrical member. The movable iron core 404 is attracted toward the fixed iron core 401 by a magnetic attractive force generated by a magnetic flux flowing between the lower end surface 401 g of the fixed iron core 401 and the upper end surface 404 c of the movable iron core 404.

In the central part of the movable iron core 404, there is formed a recess 404b that is recessed from the upper end surface 404c side to the lower end surface 404a side. A fuel passage hole 404d is formed in the upper end surface 404c and the bottom surface 404 'of the recess 404b as a fuel passage 101d penetrating to the lower end surface 404a side in the direction along the central axis 100a. The bottom surface 404 'of the recess 404b is formed with a through hole 404e that penetrates to the lower end surface 404a in the direction along the central axis 100a. The plunger rod 102 is provided so as to be inserted through the through hole 404e.

A plunger cap 410 is fixed to the plunger rod 102 by fitting, and has a large diameter portion 102a. The intermediate member 414 is a cylindrical member having a recess 404 b that forms a step on the inner and outer periphery, the inner peripheral surface 414 a is in contact with the plunger rod large diameter portion 102 a upper surface 102 b, and the outer peripheral surface 414 b is connected to the movable iron core 404. It is in contact with the bottom surface 404b 'of the recess 404b. There is a gap g1 between the lower surface 102c of the plunger rod large diameter portion and the bottom surface 404b 'of the movable iron core 404 recess 404b. The length obtained by subtracting the height h formed by the upper surface 102b and the lower surface 102c of the plunger rod large diameter portion 102a from the height 414h of the concave step of the intermediate member 414 is the gap g1.
The upper end portion of the first spring member 405 is in contact with the lower end surface of the spring force adjusting member 106, and the lower end portion of the first spring member 405 is in contact with the upper spring receiver 410 a of the plunger cap 410 and the plunger cap 410 is interposed through the plunger cap 410. The rod 102 is urged downward. The upper end portion of the third spring member 406 contacts the lower spring receiving portion 410b of the plunger cap 410, and the lower end portion of the third spring member 406 contacts the upper surface 414c of the intermediate member 414 so that the intermediate member 414 moves in the valve closing direction. Energized.

The upper end portion of the second spring 407 is in contact with the lower surface 404a of the movable core 404, and the lower end portion of the second spring 407 is in contact with the step portion 300d of the nozzle body 300b to urge the movable core 404 in the valve opening direction. . That is, the electromagnetic valve (fuel injection device 100) of the present embodiment is attached to the first spring member 405 that urges the valve body 303 in the valve closing direction, the stopper portion 410c, or the valve body 303, and the preliminary stroke. A third spring member 406 that biases the intermediate member 414 in the direction of increasing the gap (g1); and a second spring member 407 that biases the movable iron core 404 in the valve opening direction. The spring force of the third spring member 406> the spring force of the second spring member 407. Thereby, the preliminary stroke gap (g1) is formed in the valve-closed state.

The coil 402 is assembled on the outer peripheral side of the fixed iron core 401 and the cylindrical member large-diameter portion 300b in a state of being wound around a bobbin, and a resin material is molded around it. A connector 105 having a terminal 104 drawn out from the coil 402 is integrally formed by a resin material used for the mold.

(Description of operation)
Next, the operation of the fuel injection device 100 in the present embodiment will be described. This will be described mainly with reference to FIG. 2 which is an enlarged view of the electromagnetic drive unit 400 and FIGS. 3A and 4A are the same, and in FIGS. 3B and 4B, the operations of the movable iron core 404 and the intermediate member 414 from t0 to t6 are the same.

(Valve closed state definition, gap explanation)
When the coil 402 is not energized, the plunger rod 102 is urged by the first spring member 405 in the valve closing direction. On the other hand, a force obtained by subtracting the biasing force of the third spring member 406 from the biasing force with the second spring member 407 works in the valve opening direction, and the biasing force of the first spring member 405 is in this valve opening direction. Therefore, the plunger rod 102 is in contact with the valve seat 301a and is closed. This state is called a closed valve stationary state. At this time, the movable iron core 404 is in contact with the outer peripheral side step 414b of the intermediate member 414 and is disposed at the valve closing position. In addition, in the valve closing state of the fuel injection device of the present embodiment, the gap related to the movable part related to the valve opening operation is configured as follows. There is a gap g1 between the bottom surface 404b ′ of the concave portion 404b of the movable iron core 404 and the lower surface 102c of the plunger rod large diameter portion 102a.

(Operation after energization)
After energization of the coil 402 (P1), a magnetomotive force is generated by the electromagnet constituted by the fixed iron core 401, the coil 402, and the housing 403. By this magnetomotive force, a magnetic flux circulating around a magnetic path constituted by the fixed iron core 401, the housing 403, the large diameter portion 300 d of the nozzle body, and the movable iron core 404 configured to surround the coil 402 flows. At this time, a magnetic attractive force acts between the upper end surface 404 c of the movable iron core 404 and the lower end surface 401 g of the fixed iron core 401, and the movable iron core 404 and the intermediate member 414 are displaced toward the fixed iron core 401. Thereafter, the movable iron core 404 is displaced by g1 until it contacts the lower surface 102c of the plunger rod large diameter portion 102a (between t0 and t1). At this time, the plunger rod 102 does not move.

Thereafter, when the movable iron core 404 comes into contact with the lower surface 102c of the large-diameter portion of the plunger rod 102 at the timing t1, the plunger rod 102 is pulled up by receiving an impact force from the movable iron core 404, and the plunger rod 102 is separated from the valve seat 301a. As a result, a gap is formed in the valve seat portion, and the fuel passage is opened. In response to the impact force, the valve starts to open, so that the plunger rod 102 rises sharply (3A). At this time, the movable iron core and the intermediate member 414 operate in the same manner as the plunger rod 102.

Thereafter, when the plunger rod 102 is displaced by g3 and the upper surface 404c of the movable iron core 404 contacts the lower surface 401g of the fixed iron core 401 at the timing t2, the intermediate member 414 is displaced upward (3B), and the movable iron core 404 is moved. Is displaced downward (3B ′), contacted again (3C), separated again, the plunger rod 102 is displaced upward (3D), and the movable iron core 404 is displaced downward (3D ′), and then stabilized to the displacement of g3 ( 3E).

(Function, effect)
In the present invention, an intermediate member 414 is provided below the third spring 406 that generates a spring force on the movable iron core 404 and the plunger rod 102, and the bottom surface 404 b ′ of the concave portion 404 b of the movable iron core 404 and the large diameter portion of the plunger rod 102. It is disposed in contact with the upper surface 102b. Therefore, the movable iron core 404, the plunger rod 102, and the intermediate member 414 perform valve opening operation. When the movable iron core 404 and the fixed iron core 401 collide at the timing t2, the movable iron core 404 moves in the valve closing direction. The member 414 and the plunger rod 102 continue to move in the valve opening direction. In this state, no spring force acting between the movable iron core 404 and the plunger rod 102 is generated, and the spring force is disconnected. Therefore, the spring force that changes with the movement of the movable iron core 404 is not transmitted to the plunger rod 102, and conversely, the spring force that changes with the movement of the plunger rod 102 is not transmitted to the movable iron core 404. Each other independently vibrates due to the collision (3B, 3B ′). Also, when the collision occurs again (3C), the movable iron core 404 again bounces in the valve closing direction (3D ′), and the plunger rod 102 bounces in the valve opening direction (3D), but each other does not transmit / receive force. The plunger rod 102 and the movable iron core 404 have a small force while moving without applying a spring force that changes with each other's movement. Therefore, compared with the case where the spring force which changes with a mutual movement is acting, the convergence of the bound of a movable part becomes quick (3E). This effect makes it possible to stabilize the fuel injection amount.
Further, in the valve-closed state, the gap g1 in which the movable iron core 404 is displaced is defined as the recess height 414h of the intermediate member 414 and the height h of the plunger rod large diameter portion 102a (height h between the upper surface 102b and the lower surface 102c of 102a). Therefore, since it is determined by the component dimensions, adjustment in the assembly process becomes unnecessary, and the assembly process can be simplified.

At timing t3, when the energization to the coil 402 is interrupted (P2), the magnetic force starts to disappear, and the valve closing operation is performed by the biasing force of the spring in the valve closing direction. After the displacement of the plunger rod 102 becomes zero at the timing t4, the plunger rod 102 comes into contact with the valve seat 301a to complete the valve closing. Further, since the intermediate member 414 is in contact with the upper surface 102b of the plunger rod large diameter portion 102a, the displacement does not become smaller than zero.

On the other hand, the movable iron core 404 is further displaced in the valve closing direction after the displacement of the intermediate member 414 becomes zero at the timing of t4. After the movable iron core 404 is displaced most in the valve closing direction at the timing of t5, it is displaced in the valve opening direction so that the displacement becomes zero again by the second spring member. At the timing of t6, the displacement becomes 0 again, and the movable iron core 404 and the intermediate member 414 collide.

FIG. 4 shows the movable iron core 404 and the intermediate member 414 when the spring force of the second spring member 407 and the third spring member 406 for securing the preliminary stroke gap (g1) in the valve closing operation is not set. The displacement is shown. Here, after the movable iron core 404 and the intermediate member 414 collide at the timing of t6 and the displacement becomes zero, the movable iron core 404 and the intermediate member 414 move in the valve opening direction. Thereafter, the movable iron core 404 and the intermediate member 414 operate in a direction in which the preliminary stroke gap (g1) is eliminated, and the bottom surface 404b 'of the movable iron core 404 collides with the lower surface 102c of the plunger rod large diameter portion at the timing t7'. At this timing t7 ', the preliminary stroke gap (g1) disappears.

The intermediate member 414 and the intermediate member 414 are further displaced in the valve opening direction from the preliminary stroke gap (g1) between t7 'and t8, and the state without the preliminary stroke gap (g1) continues for a certain period of time. In this state, when the next pulse signal is sent, there is no preliminary stroke gap (g1), so that the movable iron core 404 cannot open the plunger rod 102 and fuel injection may not be possible.

On the other hand, FIG. 3 shows a case where the spring force of the second spring member 407 and the third spring member 406 for securing the preliminary stroke gap (g1) in the valve closing operation is set. The intermediate member 414 is displaced in the valve closing direction again by the spring force of the third spring member 406 without being displaced in the valve opening direction from the preliminary stroke gap (g1) during the period from t6 to t7. As a result, the intermediate member 414 is movable. The preliminary stroke gap (g1) of the iron core 404 can be secured.

That is, the electromagnetic valve (fuel injection device 100) of this embodiment is movable in a closed state, with a valve body 303 that opens and closes a flow path, a movable iron core 404 that moves the valve body 303 in the valve opening direction by magnetic attraction. And an intermediate member 414 configured to form a preliminary stroke gap (g1) between the iron core 404 and the valve body 303. The electromagnetic valve (fuel injection device 100) includes a movable iron core spring (second spring member 407) that urges the movable iron core 404 in the valve opening direction, and an intermediate member that urges the intermediate member 414 in the valve closing direction. A spring (third spring member 406).

Then, when the intermediate member 414 moves in the direction of reducing the preliminary stroke gap (g1), the spring force of the intermediate member spring (third spring member 406) for securing the preliminary stroke gap (g1) is set. ing. More specifically, when the movable core 404 collides with the intermediate member 414 after the valve body 303 is closed, the movable core spring (second spring) is set so that the moving distance of the intermediate member 414 is less than the preliminary stroke gap (g1). The spring force of the spring member 407) and the intermediate member spring (third spring member 406) is set. In particular, when the movable core 404 collides with the intermediate member 414 at the maximum speed after the valve body 303 is closed, the movable core spring (second spring) is set so that the moving distance of the intermediate member 414 is less than the preliminary stroke gap (g1). The spring force of the spring member 407) and the intermediate member spring (third spring member 406) is set.

Further, a target fuel pressure is set on a common rail (not shown) to which the electromagnetic valve (fuel injection device 100) is attached. When the assumed common rail fuel pressure is maximum, the solenoid valve (fuel injection device 100) of the present embodiment is intermediate when the movable iron core 404 collides with the intermediate member 414 after the valve body 303 is closed. The spring force of the movable core spring (second spring member 407) and the intermediate member spring (third spring member 406) is set so that the moving distance of the member 414 is less than the preliminary stroke gap (g1). . Particularly, it is desirable that the vehicle collides at the maximum speed. As a result, the return to the initial valve closing state is accelerated, and the stability of the fuel injection amount is improved.

In order to secure the preliminary stroke gap (g1) in the valve closing operation, the present inventors have a relationship in which the maximum collision speed V at which the movable iron core 404 collides with the intermediate member 414 in the valve closing operation is expressed by the following Equation 1. In some cases, it has been found that the spring force F3 of the third spring member needs to satisfy the relationship of the following mathematical formula 2. Therefore, in the solenoid valve (fuel injection device 100) of the present embodiment, the spring force of the plunger rod spring, the movable core spring, and the intermediate member spring is set so that the following formulas 1 and 2 are satisfied. .

In Equations 1 and 2, the spring force of the plunger rod spring (first spring member 405) is F1, the spring force of the movable iron core spring (second spring member 407) is F2, and the intermediate member spring (first member). The spring force of the third spring member 406) is F3, the differential pressure between the upstream side of the movable iron core 404 and the downstream side of the movable iron core 404 is F4, the spring constant of the plunger rod spring (first spring member 405) is k1, and is movable. The spring constant of the iron core spring (second spring member 407) is k2, the spring constant of the intermediate member spring (third spring member 406) is k3, the mass of the intermediate member 414 is m1, and the mass of the movable iron core 404 is m2. The mass of the valve body 303 was m3. Note that g1 and g2 have the following relationship as described above.

g1 is a gap between the lower surface 102c of the plunger rod large diameter portion 102a and the bottom surface 404b ′ of the concave portion 404b of the movable iron core 404 when the valve is closed, and g2 is an upper end surface 404c of the movable iron core 404 and a lower end surface 401g of the fixed iron core 401. It is a gap between them.
V = {(k1-k3) * g2 ^ 2 + (F1-F3 + F4) * g2} / (m2 + m3) ... (1)
F2> {(1/2 * (m1 + m2) * V ^ 2-1 / 2 * (k2-k3) * G1 ^ 2) / G1} + F3 ... (2)
In addition, although the flow path is formed in the movable iron core 404, since this becomes a throttle and pressure loss occurs, a differential pressure is generated between the upstream side and the downstream side. The differential pressure F4 of the movable iron core 404 indicates the differential pressure generated at the maximum collision speed V at which the movable iron core 404 collides with the intermediate member 414 in the valve closing operation.

Accordingly, the spring force F2 of the movable core spring (second spring member 407) and the intermediate member spring (third spring) are set so that the amount of upward displacement of the movable core 404 in the valve closing operation becomes smaller than the preliminary stroke gap g1. By setting the spring force F3 of the member 406), the state where the gap g1 is shortened is suppressed, so that the stability of the valve opening operation is improved.

In the configuration of this embodiment, the outer diameter 414D of the intermediate member 414 is smaller than the inner diameter 401D of the fixed iron core. Therefore, when the fuel injection device is assembled, the gap g1 is determined by the step height 414h of the intermediate member 414 and the height h of the plunger rod large diameter portion 102a, and then the spring force adjusting member 106 and the first spring member 405 are used. Since the plunger cap 410, the plunger rod 102, the third spring member 406, and the intermediate member 414 can be integrated in advance into the fuel injection device without being inserted, the assembly is easy but stable. It is possible to manage the gap g1. In the present embodiment, the large-diameter portion 414D of the intermediate member 414 is made smaller than the inner diameter 401D of the fixed iron core 401. When the outer diameter is larger than the outermost diameter 414D of the intermediate member 414, the outermost diameter of the plunger cap 410 may be made smaller than the inner diameter 401D of the fixed iron core 401.

In this embodiment, even if there is no movable iron core 404 recess 404b and the same surface as 404c, the same effect as this embodiment can be obtained. By providing the concave portion 404b of the movable iron core 404, the intermediate member 414 can be arranged on the lower side, the length of the plunger rod 102 in the on-off valve direction can be shortened, and the plunger rod 102 with high accuracy can be obtained. It is because it becomes possible to comprise.

The configuration of the second embodiment of the present invention will be described with reference to FIG. In the figure, parts having the same numbers as those in the first embodiment are not described in detail because there is no difference in configuration and effect.

In the valve-closed state, the movable iron core 404 has a concave portion 404b ′ that is recessed from the lower end surface side to the upper end surface side of the central portion. The bottom surface 404e of the concave portion 404b ′ has a movable iron core 404 in a direction along the central axis 100a. A through-hole 404e that penetrates to the upper end surface side is formed. In addition, a convex intermediate member 414 is inserted into the through-hole 404f from the downstream side, and the upper surface 414b of the large-diameter portion contacts the concave portion 404b 'of the movable iron core 404. Further, the intermediate member 414 is formed with a through hole 414e that penetrates in the direction along the central axis 100a, and the plunger rod 102 is provided so as to be inserted into the through hole 414e. In the closed state, the upper end surface 414c of the intermediate member 414 and the lower end surface 102g of the plunger rod large diameter portion 102f are in contact with each other.

The height from the upper surface 414 f of the large-diameter portion of the intermediate member 414 to the upper end surface 414 f is larger than the height from the bottom surface 404 e of the concave portion of the movable iron core 404 to the upper end surface 404 c by g 1.

Here, the configuration of the third spring member 406 will also be described.
The third spring member 406 is accommodated in the recess 404 ′ of the movable iron core 404. One end of the third spring member 406 is engaged with a bottom surface 415b of a recess recessed from the upper end side to the lower end surface side of the central portion of the stopper 415 housed in the recess 404b ′ of the movable iron core 404, and the third spring member 406 is engaged. Is engaged with the lower end surface 414c of the intermediate member 414. That is, the electromagnetic valve (fuel injection device 100) of the present embodiment includes the third spring member 406 that biases the intermediate member 414 in the valve opening direction, and the intermediate member 414 is movable with the valve body 303 by the third spring member 406. By biasing the iron core 404 in the valve opening direction, a preliminary stroke gap (g1) in the valve-closed state is formed.

In this embodiment, the lower end surface 415c of the stopper 415 and the stepped portion 300d of the nozzle body 300b are in contact, but the stopper 415 is fixed to the movable iron core 404 and forms a gap with the stepped portion 300d of the nozzle body 300b. In some cases.
Further, a stopper portion 415a of the stopper 415 is disposed through a gap (g2) larger than the preliminary stroke gap (g1) with respect to the lower end surface 414c of the intermediate member 414.

Also in the present embodiment, when the movable iron core 404 collides with the intermediate member 414 after the valve body 303 is closed as in the first embodiment, the moving distance of the intermediate member 414 is less than the preliminary stroke gap (g1). The spring force of the movable iron core spring (second spring member 407) and the intermediate member spring (third spring member 406) is set. In particular, when the movable core 404 collides with the intermediate member 414 at the maximum speed after the valve body 303 is closed, the movable core spring (second spring) is set so that the moving distance of the intermediate member 414 is less than the preliminary stroke gap (g1). The spring force of the spring member 407) and the intermediate member spring (third spring member 406) is set.

The solenoid valve (fuel injection device 100) is the case where the assumed common rail fuel pressure is maximum, and the solenoid valve (fuel injection device 100) of the present embodiment has the movable iron core 404 in the middle after the valve body 303 is closed. The movable core spring (second spring member 407) and the intermediate member spring (third spring member 406) so that the moving distance of the intermediate member 414 is less than the preliminary stroke gap (g1) when it collides with the member 414. The spring force is set. Particularly, it is desirable that the vehicle collides at the maximum speed. As a result, the return to the initial valve closing state is accelerated, and the stability of the fuel injection amount is improved.

Furthermore, the electromagnetic valve (fuel injection device 100) is set so that the maximum collision speed V at which the movable iron core 404 collides with the intermediate member 414 in the valve closing operation satisfies the relationship of the mathematical expressions 1 and 2 of the embodiment.

In addition, this invention is not limited to each above-mentioned Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 100 ... Fuel injection apparatus 101 ... Fuel passage 102 ... Plunger rod 200 ... Fuel supply part 300 ... Nozzle part 301a ... Valve seat 301b ... Fuel injection hole 311 ... Movable Iron core receiver 400... Electromagnetic drive unit 401... Fixed iron core 402... Coil 403... Housing 404 ... Movable iron core 405 ... First spring member 406. ..Second spring member 414 ... intermediate member

Claims

A valve body for opening and closing the flow path;
A movable iron core that moves the valve body in the valve opening direction by magnetic attraction;
An intermediate member configured to form a preliminary stroke gap (g1) between the movable iron core and the valve body in a closed state;
A movable core spring that biases the movable core in the valve opening direction;
An intermediate member spring for biasing the intermediate member in the valve closing direction,
When the movable iron core collides with the intermediate member after the valve body is closed, the movable core spring and the intermediate member spring are arranged such that the moving distance of the intermediate member is less than the preliminary stroke gap (g1). A solenoid valve characterized in that a spring force is set.
The solenoid valve according to claim 1,
The movable core spring and the intermediate member so that the moving distance of the intermediate member becomes less than the preliminary stroke gap (g1) when the movable core collides with the intermediate member at the maximum speed after the valve body is closed. An electromagnetic valve characterized in that the spring force of the spring is set.
The solenoid valve according to claim 1,
When the fuel pressure of the common rail to which the solenoid valve is attached is maximum, and the movable iron core collides with the intermediate member after the valve body is closed, the movement distance of the intermediate member is a preliminary stroke gap (g1 The electromagnetic valve is characterized in that spring forces of the movable iron core spring and the intermediate member spring are set to be less than.
The solenoid valve according to claim 1, wherein the spring force of the plunger rod spring is F1, the spring force of the movable core spring is F2, the spring force of the intermediate member spring is F3, the upstream side of the movable core 404 and the movable core 404. , The spring constant for the plunger rod spring is k1, the spring constant for the movable core spring is k2, the spring constant for the intermediate member spring is k3, the mass of the intermediate member 414 is m1, and the movable core 404 is Is set to m2 and the mass of the valve body 303 is set to m3, the spring force of the plunger rod spring, the movable core spring, and the intermediate member spring is set so that the following formulas 1 and 2 are satisfied. A solenoid valve characterized by that.