JP2022146785A - Gas fuel injection valve - Google Patents

Abstract

To provide a gas fuel injection valve which can prevent the generation of a lateral displacement between a bottom face and an apex face of an annular cushion member when the rubber-made cushion member receives a compression load between both cores due to the suction of a fixed core with respect to a movable core.SOLUTION: In an annular cushion member 52, areas of an internal peripheral side tapered face 55 and an external peripheral side tapered face 56 are made to differ from each other by differentiating a gradient α of the internal peripheral side tapered face 55 and a gradient β of the external peripheral side tapered face 56. When a the annular cushion member 52 is compressively deformed, a lateral displacement between a bottom face 53 and an apex face 54 of the annular cushion member 52 is prevented by moving the rubber of the annular cushion member 52 to a wide-area tapered face side having small resistance over its entire periphery.SELECTED DRAWING: Figure 3

Description

The present invention relates to a gas fuel injection valve that supplies natural gas such as CNG, LPG, etc. as fuel to an engine. a fixed core coaxially connected to the other end of the valve housing; and a valve portion that opens and closes the nozzle hole in cooperation with the valve seat. A valve body is slidably fitted on the inner peripheral surface of the valve housing, and a valve body is provided on the outer periphery of the fixed core and is connected to the suction surface of the valve housing. , a coil for applying an attractive force to the movable core to the fixed core in order to open the valve body; A gas fuel injection valve in which an annular cushion member made of rubber is joined to the surface to be attracted of the movable core, the rubber annular cushion member coming into contact with the suction surface when the fixed core is attracted to the movable core. Regarding improvements.

Such a gaseous fuel injection valve is already known as disclosed in Patent Document 1 below.

JP 2007-40245 A

In such a gas fuel injection valve, when the fixed core attracts the movable core by energizing the coil, the rubber ring-shaped cushion member joined to the attracted surface of the movable core hits the attraction surface of the fixed core. By contacting and compressing and deforming, the contact impact force of both cores can be alleviated, their durability can be improved, and noise generation can be suppressed.

By the way, in the gas fuel injection valve described in Patent Document 1, the annular cushion member has a bottom surface joined to the surface to be attracted of the movable core, a top surface parallel to the bottom surface, and a top surface and a bottom surface. It has an inner tapered surface that connects the inner peripheral edges of each other and an outer tapered surface that connects the outer peripheral edges of the top and bottom surfaces. are set equal.

In such a device, when the annular cushion member receives a compressive load between the two cores due to the attraction of the fixed core to the movable core due to the energization of the coil, the rubber side of the annular cushion member is generated at each part in the circumferential direction of the annular cushion member. Inconsistent directional movement causes the annular cushion member to experience lateral misalignment between the bottom and top surfaces, which causes the top surface of the annular cushion member to rub against the fixed core and reduce the resistance of the annular cushion member. There are drawbacks such as impairing the wear resistance, exerting lateral pressure on the movable core, i.e., the valve body, increasing the sliding resistance of the valve body against the valve housing, and lowering the responsiveness of the valve body.

The present invention has been made in view of such circumstances. For gas fuel, the lateral movement of the rubber of the member is made constant, thereby preventing lateral displacement between the bottom surface and the top surface of the annular cushion member, and making it possible to eliminate the above drawbacks. The object is to provide an injection valve.

In order to achieve the above object, the present invention provides a valve housing, a nozzle member fixed to one end of the valve housing and having a valve seat and a nozzle hole penetrating the central portion of the valve seat, and the valve housing. A fixed core that is coaxially connected to the other end and a valve part that opens and closes the nozzle hole in cooperation with the valve seat are connected to a movable core that makes the sucked surface face the suction surface of the fixed core. a valve body slidably fitted on the inner peripheral surface of the valve housing; a coil that applies an attractive force to the core; and a return spring that is contracted between the fixed core and the movable core to bias the movable core in the valve closing direction of the valve body. (2) In a gas fuel injection valve in which an annular cushion member made of rubber that abuts against the suction surface is joined when the fixed core is attracted to the movable core, the annular cushion member is joined to the surface to be sucked. A bottom surface, a top surface parallel to this bottom surface, an inner peripheral tapered surface that increases in diameter from the bottom surface side to the top surface side so as to connect the inner peripheral edges of the top surface and the bottom surface, and the top surface It has an outer peripheral tapered surface that decreases in diameter from the bottom surface side to the top surface so as to connect the outer peripheral edges of the surface and the bottom surface, and the gradient of the inner peripheral tapered surface and the outer peripheral tapered surface A first feature is that the gradients are set to be different from each other.

In addition to the first feature, the present invention has a second feature that the slope of the inner tapered surface is set larger than the slope of the outer tapered surface.

Furthermore, in addition to the first characteristic, the present invention has a third characteristic that the gradient of the outer circumferential tapered surface is set larger than the gradient of the inner circumferential tapered surface.

According to the first feature of the present invention, in the annular cushion member, the inner and outer tapered surfaces have different taper angles, so that the tapered surface with a smaller taper angle has a larger surface area. becomes large. As a result, when the coil is energized, the fixed core attracts the movable core, and when the annular cushion member is compressed between the two cores, the rubber constituting the annular cushion member has a lower resistance side, i.e., a larger surface area. It tends to move toward the tapered surface, and this phenomenon occurs equally at each portion along the circumferential direction of the annular cushion member, thereby preventing displacement between the bottom surface and the top surface. Therefore, the top surface of the annular cushion member does not rub against the fixed core, or the friction is reduced, and the abrasion resistance of the annular cushion member can be maintained. In addition, the annular cushion member does not apply lateral pressure to the movable core due to its compressive deformation, so that the opening and closing responsiveness of the valve body can be maintained satisfactorily.

BRIEF DESCRIPTION OF THE DRAWINGS Longitudinal sectional view showing a first embodiment of a gas fuel injection valve according to the present invention Enlarged cross-sectional view of the injection valve as seen from arrow 2 Enlarged cross-sectional view of arrow 3 in FIG. Enlarged cross-sectional view of arrow 4 in FIG. FIG. 3 is a diagram corresponding to FIG. 3 showing a second embodiment of the present invention;

First, a first embodiment of the present invention will be described with reference to the attached FIGS. 1 to 4. FIG.

1 and 2, the gas fuel injection valve I according to the present invention has a front end portion mounted in a mounting hole 1 provided in the wall of an intake pipe P1 of the engine, and injects gas fuel during the intake stroke of the engine. It can be injected into pipe P1. The valve housing 2 of the injection valve I has a cylindrical first housing portion 3 and a flange 3a at the rear end of the first housing portion 3, which has a larger diameter than the first housing portion 3 and whose front end is caulked. It consists of a cylindrical second housing portion 4 and a cylindrical third housing portion 5 having a smaller diameter than the second housing portion 4 and integrally connected to the rear end wall 4a of the second housing portion 4. , the first to third housing parts 3 to 5 are all made of a magnetic material.

The first housing part 3 is coaxially formed with a mounting hole 8 opening at its front end and a guide hole 9 opening at its rear end and having a diameter smaller than that of the mounting hole 8 and being longer. , the annular shim 10 and the disk-shaped nozzle member 11 are sequentially fitted and fixed by caulking the front edge of the first housing portion 3 inward. At this time, an annular sealing member 12 is attached to the outer periphery of the nozzle member 11 so as to be in close contact with the inner peripheral surface of the mounting hole 8 . The annular shim 10 adjusts the fitting position of the nozzle member 11 by selecting its thickness.

On the other hand, a valve body 15 is accommodated in the guide hole 9 . The valve body 15 is composed of a flange-like valve portion 16, a short shaft portion 171, a journal portion 18, a long shaft portion 172 and a movable core 19 which are coaxially and integrally connected from the front end side. A seat member 20 made of rubber is joined to the surface, and the nozzle hole 14 can be opened and closed by seating the seat member 20 on and off the valve seat 13 . The valve body 15 is made of a magnetic material.

In the valve body 15, the short shaft portion 171 and the long shaft portion 172 are formed to have sufficiently smaller diameters than the journal portion 18, and the journal portion 18 and the movable core 19 are both slidably fitted in the guide hole 9. .

A coil assembly 23 is accommodated in the second housing portion 4 . The coil assembly 23 comprises a bobbin 24, a coil 25 wound around the bobbin 24, and a resin molded portion 26 for embedding the coil 25 in the bobbin 24. An annular seal member 27 is interposed between the first housing portion 3 and the flange 3a.

The rear end wall 4a of the second housing portion 4 is integrally formed with a cylindrical fixed core 29 fitted to the inner peripheral surface of the bobbin 24, and a sealing member 28 for sealing the fitted portion is provided on the bobbin. 24 and the fixed core 29 . The movable core 19 projects its rear end into the bobbin 24 and has its surface to be attracted (rear end surface) 19a opposed to the attraction surface (front end surface) 29a of the fixed core 29 .

The valve body 15 is provided with a vertical hole 30 extending from the rear end surface to the front of the valve portion 16, and a plurality of horizontal holes 31 communicating the vertical hole 30 with the outer peripheral surface of the short shaft portion 171. At that time, an annular spring seat 32 facing the fixed core 29 side is formed in the middle of the vertical hole 30 .

On the other hand, from the fixed core 29 to the front half of the third housing portion 5, a support hole 35 communicating with the vertical hole 30 is formed in the center of them. An inlet hole 36 with a larger diameter is provided which is continuous with the support hole 35 . A pipe-shaped retainer 37 is press-fitted into the support hole 35 to support a return spring 33 that urges the valve body 15 toward the valve seat 13 side between itself and the spring seat 32. After adjusting the set load of the spring 33 , the retainer 37 is fixed to the third housing portion 5 by crimping from the outer periphery of the third housing portion 5 . Reference numeral 38 indicates the caulking portion. A fuel filter 39 is attached to the inlet hole 36 .

From the rear end of the second housing part 4 to the front half of the third housing part 5, a resin mold part 41 is formed which covers the outer peripheral surfaces thereof and which integrally includes a coupler 40 on one side. , hold a current-carrying terminal 42 connected to the coil 25 .

A pair of front and rear synthetic resin ring members 46, 46' defining an annular groove 45 are fitted to the outer periphery of the front end portion of the first housing portion 3, and a sealing member 47 is fitted in the annular groove 45. As shown in FIG. The seal member 47 is in close contact with the inner peripheral surface of the first housing portion 3 when the first housing portion 3 is inserted into the mounting hole 1 of the intake pipe P1 of the engine.

An annular groove 49 is formed in the outer periphery of the rear end portion of the third housing portion 5, and a seal member 50 is mounted therein. The seal member 50 is in close contact with the inner peripheral surface of the gas fuel distribution pipe P2 when the third housing portion 5 is inserted into the gas fuel distribution pipe P2.

The outer peripheral surface of the journal portion 18 and the outer peripheral surface of the front half of the movable core 19 are coated with a fluororesin film 44 .

As shown in FIGS. 3 and 4, a rubber ring-shaped cushion member 52 facing the suction surface 29a of the fixed core 29 is bonded to the suction surface 19a of the movable core 19 by baking.

The annular cushion member 52 has a flat annular bottom surface 53 joined to the attracted surface 19a of the movable core 19 and a flat annular top surface parallel to the annular bottom surface 53 and facing the suction surface 29a of the fixed core 29. 54, an inner tapered surface 55 that connects the inner peripheral edges of the bottom surface 53 and the top surface 54, and an outer tapered surface 56 that connects the outer peripheral edges of the bottom surface 53 and the top surface 54. there is Here, the inner peripheral tapered surface 55 is provided with a gradient α that increases in diameter from the bottom surface 53 side to the top surface 54 side. In the present invention, the former, ie, the inner peripheral side tapered surface 55, has a gradient β, and the latter, ie, the outer peripheral side tapered surface 56, has a different gradient β. In this first embodiment, the former gradient α is set approximately twice the latter gradient β. As a result, the area of the inner tapered surface 55 is sufficiently larger than the area of the outer tapered surface 56 .

Further, in the illustrated example, each connecting portion between the inner peripheral side tapered surface 55 and the outer peripheral side tapered surface 56 and the top surface 54 is formed as smooth circular arc surfaces 57 and 58 .

The top surface 54 of the annular cushion member 52 is provided with a plurality of notches 59 arranged at equal intervals in the circumferential direction.

Next, the operation of this first embodiment will be described.

When the coil 25 is not energized, the valve body 15 is pushed forward by the biasing force of the return spring 33 to seat the seat member 20 on the valve seat coating 51 of the valve seat 13 . In this state, the gas fuel sent from the gas fuel tank (not shown) to the distribution pipe P2 flows into the inlet hole 36 of the valve housing 2 and is filtered by the fuel filter 39. , and stand by in the guide hole 9 through the vertical hole 30 and the horizontal holes 31 .

When the coil 25 is energized, the magnetic flux generated thereby runs sequentially through the fixed core 29, the second housing part 4, the flange 3a, and the movable core 19, and the magnetic force causes the movable core 19 to be fixed against the set load of the return spring 33. The opening limit of the seat member 20 with respect to the valve seat 13 is regulated by being attracted to the core 29 and the annular cushion member 52 of the movable core 19 coming into contact with the attraction surface 29a of the fixed core 29 . Then, the gas fuel waiting in the guide hole 9 passes through the valve seat 13 and is injected into the intake pipe P1 of the engine from the nozzle hole 14, and the amount of fuel injection is controlled by the valve opening time of the valve body 15. .

By the way, when the fixed core 29 is attracted to the movable core 19, the annular cushion member 52 reduces the contact impact between the two cores 29 and 19 due to its compressive deformation, thereby suppressing the generation of noise and the vibration of the valve body 15. contribute to

Moreover, when the annular cushion member 52 is compressed and deformed, the gradient α of the inner circumferential tapered surface 55 is set larger than the gradient β of the outer circumferential tapered surface 56 . When a compressive load is applied between the top surface 54 and the top surface 54, most of it moves to the side of less resistance, that is, to the side of the inner peripheral tapered surface 55 having a larger area. Since such a phenomenon occurs over the entire circumference of the annular cushion member 52, occurrence of deviation between the bottom surface 53 and the top surface 54 can be prevented. As a result, friction between the annular cushion member 52 and the fixed core 29 is suppressed, and the wear resistance thereof can be enhanced. Moreover, preventing the occurrence of deviation between the bottom surface 53 and the top surface 54 also suppresses the side pressure to the valve body 15 due to the deviation, and the opening/closing responsiveness of the valve body 15 can be improved.

When the coil 25 is energized, that is, when the fixed core 29 is attracted to the movable core 19, the annular cushion member 52 secures a small gap between the attraction surface 29a of the fixed core 29 and the attracted surface 19a of the movable core 19. , when the coil 25 is de-energized, the residual magnetism between the fixed core 29 and the movable core 19 can be reduced, and the valve-closing responsiveness of the valve body 15 can be improved.

As described above, the fuel supplied from the fuel tank to the injection valve I contains some oil. However, since the valve seat 13 is coated with a fluororesin valve seat coating 51, the valve seat coating 51 exerts an oil-repellent action to prevent oil from adhering to the valve seat 13. become. Therefore, it is possible to prevent the seating member 20 from sticking to the valve seat 13 due to adhered oil even in cold weather, so that the valve opening responsiveness of the valve body 15 can be improved.

In addition, since the top surface 54 of the annular cushion member 52 is provided with a plurality of notches 59 arranged at equal intervals along the circumferential direction, when the coil 25 is energized, the annular cushion member 52 is attached to the stationary core attraction surface 29a. Even if they are in close contact with each other, the suction cup effect caused by the adhesion of the oil can be suppressed to prevent the annular cushion member 52 from sticking to the fixed core 29, thereby improving the valve closing responsiveness.

Next, a second embodiment of the present invention shown in FIG. 5 will be described.

In the second embodiment, the slope β of the outer tapered surface 56 of the annular cushion member 52 is set larger than the slope α of the inner tapered surface 55 . Therefore, the area of the outer tapered surface 56 is larger than the area of the inner tapered surface 55 . Other configurations are the same as those of the first embodiment, and similar configurations are given the same reference numerals as those of the first embodiment in FIG. 5, and the description thereof is omitted.

According to the second embodiment, when the annular cushion member 52 is compressed and deformed, the rubber constituting the annular cushion member 52 receives a compressive load between the bottom surface 53 and the top surface 54, and the side with less resistance, that is, the area is increased. Most of them move to the wide outer peripheral tapered surface 56 side. Since such a phenomenon occurs over the entire circumference of the annular cushion member 52, it is possible to prevent the occurrence of displacement between the bottom surface 53 and the top surface 54, and the same effect as in the first embodiment can be obtained.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the present invention described in the claims. It is possible.

For example, in order to avoid the sucker effect of the annular cushion member 52 on the fixed core 29, instead of the notch 59 on the top surface 54, the top surface can be processed to have a pear-finished surface.

I... Injection valve for gas fuel α... Gradient of inner peripheral side tapered surface ?... Gradient of outer peripheral side tapered surface 2... Valve housing 11... Nozzle member 13... Valve seat 14 Nozzle hole 15 Valve element 16 Valve portion 19 Movable core 19a Attracted surface 25 Coil 29 Fixed core 33 Return spring 52 Annular cushion member 53 Bottom surface 54 Top surface 55 Inner tapered surface 56 Outer tapered surface

Claims (3)

a valve housing (2); and a nozzle member (11) fixed to one end of the valve housing (2) and having a valve seat (13) and a nozzle hole (14) passing through the center of the valve seat (13). ), a fixed core (29) coaxially connected to the other end of the valve housing (2), and a valve portion (16) that cooperates with the valve seat (13) to open and close the nozzle hole (14). ) is connected to a movable core (19) that faces the attracted surface (19a) to the suction surface (29a) of the fixed core (29), and is slidable on the inner peripheral surface of the valve housing (2). A valve body (15) fitted to the fixed core (29) and a movable core ( 19) and a coil (25) which is contracted between the fixed core (29) and the movable core (19) to move the movable core (19) in the valve closing direction of the valve body (15). The attracted surface (19a) of the movable core (19) is provided with a return spring (33) for biasing, and when the fixed core (29) is attracted to the movable core (19), the attraction surface (29a) In a gas fuel injection valve in which a rubber annular cushion member (52) that abuts on is joined,
The annular cushion member (52) has a bottom surface (53) joined to the surface to be attracted (19a), a top surface (54) parallel to the bottom surface (53), the top surface (54) and the bottom surface (54). 53), the inner peripheral side tapered surface (55) that increases in diameter from the bottom surface (53) side to the top surface (54) side so as to connect the inner peripheral edges of the top surface (54) and the bottom surface (54) An outer tapered surface (56) having a smaller diameter from the bottom surface (53) side to the top surface (54) side so as to connect the outer peripheral edges of (53), and the inner peripheral tapered surface (56) An injection valve for gas fuel, characterized in that the slope (α) of (55) and the slope (β) of the outer peripheral tapered surface (56) are set to be different from each other. In the gas fuel injection valve according to claim 1,
A gas fuel injection valve, wherein the slope (α) of the inner peripheral tapered surface (55) is set larger than the slope (β) of the outer peripheral tapered surface (56). In the gas fuel injection valve according to claim 1,
A gas fuel injection valve, wherein a slope (β) of the outer peripheral tapered surface (56) is set larger than a slope (α) of the inner peripheral tapered surface (55).

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