JPWO2018079361A1 - Fuel injection device - Google Patents

Abstract

It is an object of the present invention to provide a fuel injection device capable of shortening the moving time of the distance necessary for the valve body to receive an impact force from the movable iron core at the time of valve opening and opening the injection hole, even when the injection interval becomes short. Providing a structure that promotes the stabilization of the injection amount. In order to achieve the above object, a fuel injection device according to the present invention comprises a valve body for opening and closing a flow path, a movable iron core for moving the valve body in a valve opening direction by a magnetic attraction 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 spring for a movable iron core urging the movable iron core in the valve opening direction, and the valve closing direction of the intermediate member An intermediate member spring for biasing the movable member such that the moving distance of the intermediate member becomes less than the preliminary stroke gap (g1) when the movable iron core collides with the intermediate member after the valve body is closed. The spring force of the spring for the movable core and the spring for the intermediate member is set to.

Description

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

  As background art of this technical field, there is JP, 2011-137442, A (patent documents 1). In this publication, the fuel injection nozzle is provided with an intermediate member which slides on 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 valve closed state. By this, the movable iron core collides with the valve body at the time of valve opening, so that the moving time for the distance necessary to open the injection hole can be shortened, and the relative movement between the movable iron core and the valve becomes possible after the on-off valve. Controllability is improved.

JP 2011-137442 A

  In the fuel injection device, atomization promotion of the spray and stabilization of the injection amount are required. The aggravating factor of the spray atomization is that the fuel flow velocity becomes slow in the low lift period when the valve body 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, in the fuel injection device, it is necessary to make the opening start steep and at the same time to quickly converge the operation of the valve after the valve opening. 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 prior to the start of energization, and an impact force at the time of collision is applied to the valve body at the time of valve opening. By providing the intermediate member between the movable core and the valve body of the movable core, relative movement between the valve body and the movable core is enabled, and the injection amount can be stabilized.

  However, when the intermediate member continues to displace in the valve closing direction after closing the valve and injection is performed before returning to the valve closing standby state, a state where the gap in the displacement direction is small occurs. There is a problem that the valve behavior is not stable.

  Therefore, it is an object of the present invention to provide a fuel injection device capable of shortening the low lift period at the time of valve opening, even when the injection interval becomes short, when the valve body receives an impact force from the movable iron core at the time of valve opening. An object of the present invention is to provide a structure that improves the stability of the operation of the valve body at the time of the valve and promotes the stabilization of the injection amount.

  In order to achieve the above object, a fuel injection device according to the present invention comprises a valve body for opening and closing a flow path, a movable iron core for moving the valve body in a valve opening direction by a magnetic attraction 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 spring for a movable iron core urging the movable iron core in the valve opening direction, and the valve closing direction of the intermediate member An intermediate member spring for biasing the movable member such that the moving distance of the intermediate member becomes less than the preliminary stroke gap (g1) when the movable iron core collides with the intermediate member after the valve body is closed. The spring force of the spring for the movable core and the spring for the intermediate member is set to.

  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 to suppress the period in which the preparatory stroke gap is reduced, thereby promoting the stabilization of the fuel injection amount. Other configurations, operations and effects of the present invention will be described in detail in the following embodiments.

It is a sectional view showing the structure of the fuel injection device concerning a 1st example of the present invention, and is a longitudinal section showing a cutting plane parallel to central axis 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 the 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 the operation | movement of the movable part in case the spring force is not set corresponding to the injection command pulse in the Example of this invention. It is a sectional view showing the structure of the fuel injection device concerning a 2nd example of the present invention, and is a longitudinal section showing a cutting plane parallel to central axis 100a.

  Examples according to the present invention will be described below.

  The configuration of a fuel injection device 100 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is a cross-sectional view showing the structure of a fuel injection device according to an embodiment of the present invention, and is a longitudinal cross-sectional view showing a cross section parallel to the central axis 100a. FIG. 2 is an enlarged cross-sectional view of the electromagnetic drive unit 400 shown in FIG. FIG. 3 is a view for explaining the operation of the movable core 404. 3 (a) and 4 (a) show the ON-OFF state of the injection command pulse, and FIGS. 3 (b) and 4 (b) show the valve closing state of the plunger rod 102 as displacement 0, and the movable iron core 404. And the displacement of the intermediate member 414. The operations from t0 to t6 of the movable core 404 and the intermediate member 414 shown in FIGS. 3 (b) and 4 (b) are the same.

  The fuel injection device 100 includes a fuel supply unit 200 for supplying fuel, a nozzle unit 300 provided at its tip with a valve unit 300a for permitting or blocking the flow of fuel, and an electromagnetic drive unit for driving the valve unit 300a. And 400. In the present embodiment, an electromagnetic fuel injection device for an internal combustion engine fueled by gasoline will be described as an example. The fuel supply unit 200, the valve unit 300a, the nozzle unit 300, and the electromagnetic drive unit 400 indicate the corresponding parts with respect to the cross section shown in FIG. 1, and do not indicate a single part.

  In the fuel injection device 100 of this embodiment, the fuel supply unit 200 is formed on the upper end side of the drawing, the nozzle unit 300 is formed on the lower end side, and the electromagnetic drive unit 400 is formed 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 300 has an end opposite to the fuel supply 200 in a mounting hole (insertion hole) formed in an intake pipe (not shown) or a combustion chamber forming member (cylinder block, cylinder head, etc.) of an internal combustion engine. Be inserted. The electromagnetic fuel injection device 100 receives the supply of fuel from the fuel pipe through the fuel supply unit 200, and injects the fuel from the tip of the nozzle unit 300 into the intake pipe or the combustion chamber. Inside the fuel injection device 100, from the end of the fuel supply portion 200 to the tip portion of the nozzle portion 300, the fuel passage 101 is made to flow substantially along the central axis 100a of the electromagnetic fuel injection device 100. (101a to 101f) are configured.

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

(Description of configuration)
Hereinafter, the configurations 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 is constituted by 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 a 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 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 for filtering foreign matter mixed in the fuel is disposed.
The nozzle portion 300 includes a nozzle body 300b, and a valve portion 300a is formed at a tip end portion (lower end portion) of the nozzle body 300b. The nozzle body 300 b is a hollow cylindrical body, and constitutes a fuel passage 101 f on the upstream side of the valve portion 300 a. A movable iron core receiving portion 311 is formed in the lower fuel passage portion 101 e of the electromagnetic drive portion 400. In addition, the tip seal | sticker 103 which maintains airtightness, when it mounts in an internal combustion engine is provided in the front-end | tip part outer peripheral surface of the nozzle body 300b.

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 (lower end side tip end) of the plunger rod 102.
The injection hole forming member 301 includes a valve seat 301a which seals the fuel in contact with the valve body 303, and a fuel injection hole 301b which injects the fuel. The injection hole forming member 301 is inserted into and fixed to a recess inner circumferential surface 300 ba formed at the tip of the nozzle body 300 b. 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, constitutes a guide surface on the tip end side (lower end side) of the plunger rod 102, and moves the plunger rod 102 in the direction (opening and closing valve direction) along the central axis 100a. To guide you.

  The electromagnetic drive unit 400 includes a fixed core 401, a coil 402, a housing 403, a movable 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 stationary core 401 is also referred to as a stationary core. The movable core 404 is called a movable core, a mover or an armature.

  The fixed core 401 has a fuel passage 101 c and a joint portion 401 a 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 fixed core 401d is fitted and joined to the outer peripheral surface 401e having a larger diameter than the outer peripheral surface 401b. There is. 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. An upper end side inner peripheral surface 403 a of the housing 403 is connected to an outer peripheral surface 401 f of an outer peripheral side fixed iron core 401 d joined with an outer peripheral surface 401 e of the fixed iron core 401.

  A movable core 404 is disposed on the lower end surface 401 g side of the fixed core 401. The upper end surface 404c of the movable core 404 is opposed to the lower end surface 401g of the fixed core 401 with a gap g2 in the valve 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 a central axis inside the large diameter portion 300c of the cylindrical member. It is provided movably in the direction along 100a.

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

  At a central portion of the movable core 404, a concave portion 404b which is recessed from the upper end surface 404c to the lower end surface 404a is formed. 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. Moreover, the through-hole 404e penetrated to the lower end surface 404a side in the direction along the central axis 100a is formed on the bottom surface 404 'of the concave portion 404b. A plunger rod 102 is provided to pass through the through hole 404e.

A plunger cap 410 is fixed to the plunger rod 102 by fitting, and has a large diameter portion 102 a. The intermediate member 414 is a cylindrical member having a concave portion 404b which is a step on the inner and outer circumferences, the inner peripheral surface 414a is in contact with the plunger rod large diameter portion 102a upper surface 102b, and the outer peripheral surface 414b is a movable iron core 404. It is in contact with the bottom surface 404b 'of the recess 404b. A gap g1 is provided between the lower surface 102c of the plunger rod large diameter portion and the bottom surface 404b 'of the movable iron core 404 concave portion 404b. A length obtained by subtracting the height h formed by the upper surface 102b of the plunger rod large diameter portion 102a and the lower surface 102c from the height 414h of the recess step of the intermediate member 414 is the gap g1.
The upper end portion of the first spring member 405 abuts on the lower end surface of the spring force adjustment member 106, and the lower end portion of the first spring member 405 abuts on the upper spring bearing 410a of the plunger cap 410 and via the plunger cap 410 The rod 102 is biased downward. The upper end of the third spring member 406 abuts on the lower spring receiving portion 410b of the plunger cap 410, and the lower end of the third spring member 406 abuts on the upper surface 414c of the intermediate member 414 to close the intermediate member 414 in the valve closing direction. I am 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 bias the movable core 404 in the valve opening direction. . That is, the solenoid valve (the fuel injection device 100) of this embodiment is attached to the first spring member 405 for urging the valve body 303 in the valve closing direction, the stopper portion 410c or the valve body 303, and has a preliminary stroke. The third spring member 406 biases the intermediate member 414 in the direction to increase the gap (g1), and the second spring member 407 biases the movable iron core 404 in the valve opening direction, and the first spring member 405 Spring force> spring force of the third spring member 406> 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 large diameter portion 300b of the cylindrical member in a state of being wound around a bobbin, and a resin material is molded around the periphery. The connector 105 having the terminal 104 pulled out of the coil 402 is integrally molded by the resin material used for this mold.

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

(Closed valve state definition, explanation of clearance)
In the valve closed state where the coil 402 is not energized, the plunger rod 102 is biased in the valve closing direction by the first spring member 405. On the other hand, a force obtained by subtracting the urging force of the third spring member 406 from the urging force with the second spring member 407 is acting in the valve opening direction, and the urging force of the first spring member 405 is the valve opening direction. The plunger rod 102 is in contact with the valve seat 301a to close the valve because the biasing force is larger than the biasing force. This state is referred to as a closed valve stationary state. At this time, the movable iron core 404 abuts on the outer peripheral side step portion 414 b of the intermediate member 414 and is disposed at the valve closing position. In the closed 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 recess 404b of the movable core 404 and the lower surface 102c of the plunger rod large diameter portion 102a.

(Operation after energizing)
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. Due to this magnetomotive force, a magnetic flux is circulated around a magnetic path constituted by the fixed core 401 configured to surround the coil 402, the housing 403, the large diameter portion 300d of the nozzle body, and the movable core 404. At this time, a magnetic attraction force acts between the upper end surface 404 c of the movable core 404 and the lower end surface 401 g of the fixed core 401, and the movable core 404 and the intermediate member 414 are displaced toward the fixed core 401. Thereafter, the movable core 404 is displaced by g1 until it abuts on 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 core 404 abuts on the large diameter lower surface 102c of the plunger rod 102 at the timing of t1, the plunger rod 102 receives an impact from the movable core 404 and is pulled up, and the plunger rod 102 separates from the valve seat 301a. Thus, a gap is formed in the valve seat and the fuel passage is opened. In order to receive the impact force and start the valve opening, the rising of the plunger rod 102 becomes steep (3A). At this time, the movable core and the intermediate member 414 perform the same operation as the plunger rod 102.

  Thereafter, when the plunger rod 102 is displaced by g3 and the upper surface 404c of the movable core 404 abuts on the lower surface 401g of the fixed core 401 at the timing of t2, the intermediate member 414 is displaced upward (3B). Is displaced downward (3B '), and after contact again (3C), the plunger rod 102 is displaced upward (3D) and the movable core 404 is displaced downward (3D') and then stabilized at the displacement of g3 ((3B)) 3E).

(Action, 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 recess 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, when the movable iron core 404, the plunger rod 102, and the intermediate member 414 perform the valve opening operation and the movable iron core 404 and the fixed iron core 401 collide at 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, a spring force acting between the movable core 404 and the plunger rod 102 is not generated, and the spring force is separated. Therefore, the spring force that changes with the movement of the movable 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 along with the collision (3B, 3B '). Also, when colliding again (3C), the movable iron core 404 bounces in the valve closing direction (3D ') again, and the plunger rod 102 bounces in the valve opening direction (3D), but the two do not exchange force. The movement is performed without exerting a spring force which changes with the movement of each other, and the force which the plunger rod 102 and the movable core 404 have is small. Therefore, the convergence of the bounds of the movable parts is quicker (3E) than when the spring force that changes with the movement of each other is applied. 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 the height h of 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 of the 102a and the lower surface 102c). As the difference is determined by the component dimensions, no adjustment in the assembly process is required, and the assembly process can be simplified.

  When the coil 402 is deenergized (P2) at the timing t3, 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 of t4, the plunger rod 102 abuts on 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 core 404 is further displaced in the valve closing direction even after the displacement of the intermediate member 414 becomes zero at the timing of t4. After the movable core 404 is displaced most in the valve closing direction at the timing of t5, the second spring member is displaced in the valve opening direction so that the displacement becomes 0 again. The displacement becomes zero again at the timing of t6, and the movable core 404 and the intermediate member 414 collide with each other.

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

  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 a state in which there is no preliminary stroke gap (g1) continues for a certain time. In this state, when the next pulse signal is sent, the movable iron core 404 can not open the plunger rod 102 and there is a possibility that fuel injection can not be performed because there is no spare stroke gap (g1).

  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. During the period from t6 to t7, the intermediate member 414 is again displaced in the valve closing direction by the spring force of the third spring member 406 without being displaced in the valve opening direction from the preliminary stroke gap (g1), resulting in movable The preliminary stroke clearance (g1) of the iron core 404 can be secured.

  That is, the solenoid valve (fuel injection device 100) of the present embodiment is movable in the valve closed state with the valve body 303 for opening and closing the flow path, the movable iron core 404 for moving the valve body 303 in the valve opening direction by the magnetic attraction force. And an intermediate member 414 configured to form a preliminary stroke clearance (g1) between the iron core 404 and the valve body 303. Further, the electromagnetic valve (fuel injection device 100) is for the movable core spring (second spring member 407) for biasing the movable core 404 in the valve opening direction, and for the intermediate member for biasing the intermediate member 414 in the valve closing direction. And a spring (third spring member 406).

  When the intermediate member 414 moves in the direction to reduce 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 iron core 404 collides with the intermediate member 414 after the valve body 303 is closed, the movable iron core spring (second The spring force of the spring member 407) and the spring for the intermediate member (third spring member 406) are set. In particular, when the movable iron core 404 collides with the intermediate member 414 at the maximum speed after the valve body 303 is closed, the movable iron core spring (second The spring force of the spring member 407) and the spring for the intermediate member (third spring member 406) are set.

  The target fuel pressure is set to a common rail (not shown) to which the solenoid valve (the fuel injection device 100) is attached. Then, when the fuel pressure of the common rail assumed is maximum, the solenoid valve (fuel injection device 100) of this embodiment is intermediate when the movable iron core 404 collides with the intermediate member 414 after the valve body 303 closes. The spring forces of the movable iron core spring (second spring member 407) and the intermediate member spring (third spring member 406) are set such that the moving distance of the member 414 is less than the preliminary stroke gap (g1). . In particular, it is desirable that the collision occurs at the maximum speed. As a result, the return to the valve closing initial state is quickened, 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 the relation shown in the following Equation 1 that the maximum collision velocity V at which the movable iron core 404 collides with the intermediate member 414 in the valve closing operation. It has been found that in some cases, the spring force F3 of the third spring member needs to satisfy the relationship of Equation 2 below. Therefore, the spring force of the spring for the plunger rod, the spring for the movable core, and the spring for the intermediate member is set such that the relationship of the following Equation 1 and Equation 2 holds in the solenoid valve (fuel injection device 100) of this embodiment. .

  In Formulas 1 and 2, the spring force of the plunger rod spring (first spring member 405) is F1, the spring force of the movable core spring (second spring member 407) is F2, and the intermediate member spring (first The spring force of the third spring member 406) is F3, the differential pressure between the upstream side of the movable core 404 and the downstream side of the movable core 404 is F4, the spring constant of the plunger rod spring (first spring member 405) k1, movable The spring constant of the 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 core 404 is m2 The mass of the valve body 303 is 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 recess 404b of the movable core 404 at the time of valve closing; g2 is the upper end surface 404c of the movable core 404 and the lower end surface 401g of the fixed core 401; There 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 squeeze and a pressure loss arises, a pressure difference arises between an upstream side and a downstream side. The differential pressure of the movable core 404 is denoted by F 4 at the maximum collision velocity V at which the movable core 404 collides with the intermediate member 414 in the valve closing operation.

  Therefore, the spring force F2 of the movable iron core spring (second spring member 407) and the intermediate member spring (third spring) so that the amount of upward displacement of the movable iron 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 in which the gap g1 is shortened is suppressed, so the stability of the valve opening operation is improved.

  Further, in the configuration of the present 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 adjustment member 106 and the first spring member 405 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 in a state in which the valve is not inserted. It is possible to manage the gap g1. In the present embodiment, the large diameter portion 414D of the intermediate member 414 is smaller than the inner diameter 401D of the fixed core 401, but the outermost diameter of the members to be assembled in advance may be smaller. 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 smaller than the inner diameter 401D of the fixed core 401.

  In the present embodiment, even if the movable iron core 404 has no recess 404b and the same surface as 404c, the same effect as that of the present embodiment can be obtained. By providing the concave portion 404b of the movable core 404, the intermediate member 414 can be disposed at the lower side, and the length of the plunger rod 102 in the opening / closing valve direction can be shortened, and the plunger rod 102 with high accuracy. It is possible to configure the

  The configuration of the second embodiment of the present invention will be described with reference to FIG. In the figure, regarding the parts given the same numerals as in the first embodiment, the description is omitted because there is no difference in the construction effect.

  In the valve closed state, the movable iron core 404 has a recess 404b 'which is recessed from the lower end face side to the upper end face of the central portion. The bottom face 404e of the recess 404b' is movable iron core 404 in the direction along the central axis 100a. The through-hole 404e which penetrates to the upper end surface side is comprised. Further, the intermediate member 414 having a convex shape is inserted into the through hole 404 f from the downstream side, and the upper surface 414 b of the large diameter portion abuts on the concave portion 404 b ′ of the movable iron core 404. Furthermore, a through hole 414 e penetrating in a direction along the central axis 100 a is formed in the intermediate member 414, and a plunger rod 102 is provided in the through hole 414 e so as to be inserted. In the valve 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 large diameter upper surface 414b of the intermediate member 414 to the upper end surface 414f is larger than the height from the bottom surface 404e of the recess of the movable core 404 to the upper end surface 404c by g1.

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

In the present embodiment, the lower end surface 415c of the stopper 415 abuts on the stepped portion 300d of the nozzle body 300b, 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, the stopper portion 415a of the stopper 415 is disposed with respect to the lower end surface 414c of the intermediate member 414 via a gap (g2) larger than the preliminary stroke gap (g1).

  Also in the present embodiment, when the movable 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 core spring (second spring member 407) and the intermediate member spring (third spring member 406) is set. In particular, when the movable iron core 404 collides with the intermediate member 414 at the maximum speed after the valve body 303 is closed, the movable iron core spring (second The spring force of the spring member 407) and the spring for the intermediate member (third spring member 406) are set.

  In the case where the fuel pressure of the common rail assumed is maximum at the solenoid valve (fuel injection device 100), the movable iron core 404 is in the middle after the valve body 303 is closed in the solenoid valve (fuel injection device 100) of this embodiment. The movable iron 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 becomes smaller than the preliminary stroke gap (g1) when colliding with the member 414. The spring force of is set. In particular, it is desirable that the collision occurs at the maximum speed. As a result, the return to the valve closing initial state is quickened, and the stability of the fuel injection amount is improved.

  Further, the solenoid valve (fuel injection device 100) is set such that the maximum collision velocity V at which the movable core 404 collides with the intermediate member 414 in the valve closing operation satisfies the relationship of Equation 1 and Equation 2 of the embodiment.

  The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the embodiments described above are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations. Also, 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. In addition, with respect to a part of the configuration of each embodiment, it is possible to add, delete, and replace other configurations.

100: Fuel injection device 101: Fuel passage 102: Plunger rod 200: Fuel supply portion 300: Nozzle portion 301a: Valve seat 301b: Fuel injection hole 311: Movable Iron core receiving part 400 ... electromagnetic drive part 401 ... fixed iron core 402 ... coil 403 ... housing 404 ... movable iron core 405 ... first spring member 406 ... third spring member 407 · · · Second spring member 414 · · · intermediate member

Claims (4)

A valve body for opening and closing the flow path,
A movable core that moves the valve in a valve opening direction by a magnetic attraction force;
An intermediate member configured to form a preliminary stroke gap (g1) between the movable iron core and the valve body in a valve closed state;
A movable core spring for biasing the movable core in a valve opening direction;
An intermediate member spring which biases the intermediate member in a valve closing direction;
When the movable iron core collides with the intermediate member after the valve is closed, the movable iron 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. In the solenoid valve according to claim 1,
The movable iron core spring and the intermediate member so that the moving distance of the intermediate member becomes smaller than the preliminary stroke gap (g1) when the movable iron core collides with the intermediate member at maximum speed after the valve is closed. A solenoid valve characterized in that a spring force of a spring is set. In 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 the preliminary stroke clearance (g1 The spring force of the movable core spring and the intermediate member spring is set to be less than.   The electromagnetic valve according to claim 1, wherein the spring force of the spring for the plunger rod is F1, the spring force of the spring for the movable core is F2, the spring force of the spring for the intermediate member is F3, the upstream side of the movable iron core 404 and the movable iron core 404. The differential pressure on the downstream side is F4, the spring constant of the plunger rod spring is k1, the spring constant of the movable core spring is k2, the spring constant of the intermediate member spring is k3, the mass of the intermediate member 414 is m1, the movable core 404 The spring force of the spring for the plunger rod, the spring for the movable core and the spring for the intermediate member is set so that the relationship of the following Equation 1 and Equation 2 holds when m2 represents the mass of the valve body m3 A solenoid valve characterized by

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