JP2014062525A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge a fuel passage cross section area around a spring retainer without loosing the spring seat function of the spring retainer on a return spring.SOLUTION: A fuel injection valve includes a spring retainer 36 arranged and fixed into a fixed core 5 and having a hollow part as a center fuel passage 50 communicating the internal of a fuel inlet tube 6 with the internal of a valve housing 3, and a return spring 33 provided in a compressed state between a rear spring seat 35 at the front end of the spring retainer 36 and a front spring seat 34 of a movable core 12 for energizing a valve element 13 to the side of a valve seat 7. Between the spring retainer 36 and the fixed core 5, an outside fuel passage 51 is formed in parallel to the center fuel passage 50 to communicate the internal of the fuel inlet tube 6 with the internal of the valve housing 3.

Description

  The present invention includes a nozzle member having a valve seat and a nozzle hole, a cylindrical valve housing connected to the rear end of the nozzle member, a hollow fixed core connected to the rear end of the valve housing, A fuel inlet cylinder connected to the rear end of the fixed core, and a spring retainer disposed and fixed in the fixed core and having a hollow portion serving as a fuel passage communicating with the valve housing in the fuel inlet cylinder And a valve body that is accommodated in the valve housing and opens and closes the nozzle hole in cooperation with the valve seat, and is connected to the rear end of the valve body to face the suction surface of the front end of the fixed core. A movable core, a return spring that is contracted between a rear spring seat of the front end of the spring retainer and a front spring seat of the movable core and biases the valve body toward the valve seat, and surrounds the fixed core When energized, Relates to an improvement of a fuel injection valve with the movable core is attracted to the stationary core by the raw force comprising a coil for unseating said valve body from the valve seat.

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

Japanese Patent Application Laid-Open No. 11-303685

  In such fuel injection valves, as the engine output increases, there is a demand for an increase in the fuel flow rate at the time of opening the valve. It is conceivable to increase the diameter of the cylindrical spring retainer. However, the spring retainer supports the rear end surface of the return spring at its front end surface, and the return spring has its outer diameter determined in consideration of a predetermined valve closing load of the valve body. The outer diameter of the return spring cannot be changed. Therefore, if only the diameter of the spring retainer is increased, the spring seat function for the return spring of the spring retainer is lost.

  The present invention has been made in view of such circumstances, and without losing the spring seat function with respect to the return spring of the spring retainer, it is possible to enlarge the fuel passage cross-sectional area inside the fixed core including the inside of the spring retainer, It is an object of the present invention to provide the fuel injection valve adapted to meet the demand for increasing the fuel flow rate when the valve is opened.

  To achieve the above object, the present invention provides a nozzle member having a valve seat and a nozzle hole, a cylindrical valve housing connected to the rear end of the nozzle member, and a rear end of the valve housing. A hollow fixed core, a fuel inlet cylinder connected to the rear end of the fixed core, and a central fuel disposed and fixed in the fixed core and communicating with the valve housing in the fuel inlet cylinder A spring retainer having a hollow portion serving as a passage; a valve body housed in the valve housing; opening and closing the nozzle hole in cooperation with the valve seat; and a rear end of the valve body; A movable core facing the suction surface of the front end of the fixed core, a rear spring seat of the front end of the spring retainer, and a front spring seat of the movable core are urged to bias the valve body toward the valve seat. Enclose the return spring and the fixed core A fuel injection valve provided with a coil that attracts the movable core to the fixed core by generated magnetic force when energized, and separates the valve body from the valve seat; A first feature is that an outer fuel passage is provided between the fixed core and the central fuel passage so as to communicate the inside of the fuel inlet cylinder with the valve housing.

  According to the present invention, in addition to the first feature, the spring retainer is fitted and fixed to the inner peripheral surface of the sleeve fitted and fixed to the inner peripheral surface of the fixed core, and the outer fuel is fixed to the outer peripheral surface of the sleeve. A second feature is that the passage is formed in a groove shape.

  In addition to the second feature of the present invention, the front end portion of the sleeve projects forward from the front end of the spring retainer, and the rear end portion of the return spring is laterally shaken within the front end portion of the sleeve. The third feature is that it is accepted as regulated.

  In addition to the first feature of the present invention, the spring retainer is fitted and fixed to the inner peripheral surface of the fixed core, and the outer fuel passage is provided on at least one of the fitting surfaces of the fixed core and the spring retainer. The fourth feature is that the groove is formed.

  According to the first aspect of the present invention, the cross-sectional area of the fuel passage around the spring retainer is increased by adding the cross-sectional area of the outer fuel passage outside the spring retainer to the cross-sectional area of the central fuel passage in the spring retainer. As a result, the pressure loss of the fuel can be kept small, and a large flow rate of fuel can be passed inside and outside the spring retainer, which can meet the demand for an increase in the fuel flow rate associated with higher engine output.

  On the other hand, since the spring retainer supports the rear end of the return spring by the rear spring seat of the front end as usual, it is not necessary to change the outer diameter of the return spring, so that the change in the opening / closing characteristics of the valve body can be avoided. .

  According to the second feature of the present invention, the spring retainer is fitted and fixed to the inner peripheral surface of the sleeve fitted and fixed to the inner peripheral surface of the fixed core, and the outer fuel passage is formed in a groove shape on the outer peripheral surface of the sleeve. As a result, the sleeve with the groove-shaped outer fuel passage can be easily formed, and the productivity is improved.

  According to the third aspect of the present invention, the front end portion of the sleeve is protruded forward from the front end of the spring retainer, and the rear end portion of the return spring is received in the front end portion of the sleeve so as to restrict the lateral deflection thereof. By doing so, it is possible to prevent the return spring from being displaced from the rear spring seat by the front end portion of the sleeve and to stabilize the operation of the return spring. Even when close winding is performed so that the rear end of the return spring has high rigidity, the rear end of the close winding is disposed inside the sleeve, that is, inside the outer fuel passage. Fuel pressure loss can be suppressed without hindering the outflow of fuel from the passage.

  According to the fourth aspect of the present invention, a spring retainer is fitted and fixed to the inner peripheral surface of the fixed core, and the outer fuel passage is formed in a groove shape on at least one of the fixed core and the fitting surface of the spring retainer. Therefore, the outer fuel passage can be obtained with a simple structure.

1 is a longitudinal sectional view of a gas fuel injection valve according to a first embodiment of the present invention. The 2A section enlarged view of FIG. 2B-2B sectional view taken on the line of FIG. 2A. FIG. 2B is a view corresponding to FIG. 2A showing the second embodiment of the present invention. 3B-3B line sectional drawing of FIG. 3A. The correspondence diagram with Drawing 2A showing a 3rd embodiment of the present invention. 4B-4B sectional view taken on the line of FIG. 4A.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  First, the description starts with the description of the first embodiment of the present invention shown in FIGS.

  In FIG. 1, a gas fuel injection valve I has a front end portion attached to a mounting hole Ea provided in a pipe wall of an intake pipe E of an engine, and injects gas fuel into the intake pipe E during an intake stroke of the engine. The valve body 1 of the injection valve I is a hollow body made of a magnetic material in which a front end portion is coupled and welded to an outer peripheral surface of a cylindrical nozzle member 2 and a flange portion 2a at the rear end of the nozzle member 2. A cylindrical valve housing 3 having a gas fuel passage inside, a hollow cylindrical fixed core 5 integrally connected to the rear end of the valve housing 3 via a nonmagnetic cylindrical body 4, and the fixed core And a hollow cylindrical fuel inlet tube 6 integrally provided at the rear end of the fuel inlet 39. A fuel filter 39 is attached to the inlet of the hollow portion 6 a of the fuel inlet tube 6. The fixed core 5 is formed so that the inner diameter thereof is smaller than the inner diameter of the valve housing 3, and the suction surface 5 b at the front end is opposed to a later-described valve plunger 10 of the valve housing 3.

  The nozzle member 2 is provided with a flat valve seat 7 facing the valve housing 3, a funnel-shaped valve hole 8 penetrating through the center portion, and a nozzle hole 9 connected to a small diameter outlet of the valve hole 8. An annular shim 11 that adjusts the position of the valve seat 7 is interposed between the nozzle member 2 and the valve housing 3.

  An inner peripheral surface of the valve housing 3 is a sliding guide surface 3a, and a valve plunger 10 is slidably fitted on the sliding guide surface 3a. The valve plunger 10 has a cylindrical movable core 12 that is slidably fitted to the sliding guide surface 3 a with a rear end face facing the suction surface 5 b of the front end of the fixed core 5, and a front end of the movable core 12. A rubber seat member 17 that can be seated on the valve seat 7 is attached to the front end surface of the valve body 13 by baking. Is done. Further, on the outer peripheral surface of the valve body 13, a journal portion 13a that is slidably fitted to the sliding guide surface 3a is integrally formed. Thus, a predetermined gap corresponding to the valve opening stroke of the valve element 13 is set between the opposed surfaces of the fixed core 5 and the movable core 12 when the seating member 17 is seated on the valve seat 7.

  A coil assembly 20 is disposed from a region where the movable core 12 of the valve housing 3 is fitted to the fixed core 5 and surrounding them. The coil assembly 20 includes a valve housing 3, a bobbin 21 fitted to the outer periphery of the nonmagnetic cylindrical body 4 and the fixed core 5, and a coil 22 wound around the outer periphery of the bobbin 21. A magnetic coil housing 23 is disposed on the outer periphery of the solid 20 to cover it.

  The fixed core 5 is integrally formed with a yoke flange 24 that protrudes from the outer peripheral surface and supports the rear end surface of the bobbin 21, and the rear end portion of the coil housing 23 is fitted to the outer peripheral surface of the yoke flange 24. Further, an annular end wall 23a abutting against the front end surface of the bobbin 21 and a forward projection from the inner peripheral end of the annular end wall 23a are fitted and fixed to the outer peripheral surface of the valve housing 3 at the front end portion of the coil housing 23. The cylindrical portion 23b is integrally formed. Thus, the coil assembly 20 and the coil housing 23 are attached to the valve body 1. A resin mold layer 26 is formed on the outer peripheral surfaces of the coil housing 23 and the fuel inlet cylinder 6 so as to continuously cover them. A coupler 28 that holds a continuous energization terminal 27 is integrally formed.

  The valve plunger 10 has a large-diameter vertical hole 30 that starts from the rear end surface of the movable core 12 and ends before the front end surface, and a bottomed bottom that starts from the bottom surface of the large-diameter vertical hole 30 and ends before the front end surface of the valve body 13. A small-diameter vertical hole 31 and a plurality of horizontal holes 32, 32... That open the small-diameter vertical hole 31 to the outer peripheral surface of the front end portion of the valve body 13 in front of the journal portion 13a are provided.

  The rearward annular step formed between the large diameter vertical hole 30 and the small diameter vertical hole 31 is a front spring seat 34. A hollow cylindrical spring retainer 36 is disposed and fixed at the center of the hollow portion 5a of the fixed core 5. The front end surface of the spring retainer 36 is a rear spring seat 35 facing the front spring seat 34. A return spring 33 accommodated in the large-diameter vertical hole 30 and biasing the valve body 13 toward the valve seat 7 is contracted between the front and rear spring seats 34 and 35.

  As shown in FIGS. 1 to 2B, the hollow portion 5a of the fixed core 5 has a spring guide hole 5a1 that is substantially the same diameter as the large-diameter vertical hole 30 and is arranged coaxially therewith, and a rear end of the spring guide hole 5a1. And a mounting hole 5a2 having a diameter larger than that of the spring guide hole 5a1, and the hollow part 6a of the fuel inlet cylinder 6 is connected to the rear end of the mounting hole 5a2. The spring guide hole 5a1 accommodates the return spring 33 and restricts its lateral deflection.

  A sleeve 38 is press-fitted and fixed to the inner peripheral surface of the mounting hole 5a2, and a spring retainer 36 is press-fitted and fixed to the hollow portion 38a of the sleeve 38 while the rear spring seat 35 of the front end supports the rear end of the return spring 33. The At that time, the set load of the return spring 33 is adjusted depending on the press-fit depth of the spring retainer 36.

  The peripheral wall of the spring retainer 36 is provided with a single slit 37 extending in the axial direction, whereby the spring retainer 36 can be elastically reduced in diameter. The outer diameter of the spring retainer 36 is set to be larger than the inner diameter of the sleeve 38 in a free state in consideration of a press-fitting allowance for the hollow portion 36 of the sleeve 38.

  The hollow portion of the spring retainer 36 constitutes a central fuel passage 50 that communicates the inside of the fuel inlet cylinder 6 with the spring guide hole 5a1. The spring guide hole 5a1 communicates with the inside of the valve housing 3 via the large diameter vertical hole 30, the small diameter vertical hole 31 and the horizontal hole 32 of the valve plunger 10, so that the central fuel passage 50 eventually passes through the fuel inlet cylinder 6. The valve housing 3 is communicated.

  A plurality of outer fuel passages 51, 51... Extending in the axial direction are formed in a groove shape on the outer periphery of the sleeve 38, and these outer fuel passages 51, 51. The inside of the cylinder 6 is communicated with the spring guide hole 5a1.

  The sleeve 38 is configured such that its inner diameter is substantially the same as that of the spring guide hole 5a1. The sleeve 38 is arranged such that the front end portion thereof projects forward from the front end of the spring retainer 36, that is, the rear spring seat 35. Therefore, the inner peripheral surface of the front end portion of the sleeve 38 serves as a spring guide portion that receives the rear end portion 33a of the return spring 33 supported by the rear spring seat 35 and restricts the lateral deflection thereof.

  Referring again to FIG. 1, a pair of front and rear synthetic resin ring members 41 and 42 that define an annular front seal groove 40 are fitted on the outer periphery of the nozzle member 2. When the member 2 is inserted into the mounting hole Ea of the intake pipe E of the engine, the front O-ring 43 that is in close contact with the inner peripheral surface is mounted.

  An annular rear seal groove 45 is formed on the outer periphery of the rear end portion of the fuel inlet cylinder 6, and the inner peripheral surface of the rear seal groove 45 when the fuel distribution pipe D is fitted to the outer periphery of the fuel inlet cylinder 6. A rear O-ring 47 that is in close contact with is attached.

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

  In the demagnetized state of the coil 22, the valve plunger 10 is pressed forward by the set load of the return spring 33 to seat the seating member 17 on the valve seat 7.

  When the coil 22 is excited by energization, the magnetic flux generated by the coil 22 sequentially travels through the coil housing 23, the valve housing 3, the movable core 12, the fixed core 5, and the coil housing 23, and the magnetic force generated between the fixed core 5 and the valve plunger 10 The plunger 10 is attracted by the fixed core 5 against the set load of the return spring 33, the seating member 17 is separated from the valve seat 7, and the valve hole 8 is opened.

  When the valve hole 8 is opened, the gas fuel sent from the gas fuel tank (not shown) to the fuel distribution pipe D flows into the fuel inlet cylinder 6 and is filtered by the fuel filter 39 and travels toward the hollow portion 5a of the fixed core 5. . In the hollow portion 5 a, the gas fuel is divided into the hollow portion of the spring retainer 36, that is, the central fuel passage 50 and a plurality of outer fuel passages 51, 51... Formed between the fixed core 5 and the sleeve 38. Then, while converging at the tapered portion 5a3, the spring guide hole 5a1, the large diameter vertical hole 30, the small diameter vertical hole 31, and the horizontal holes 32, 32,. Then, the fuel is injected from the nozzle hole 9 into the intake pipe E of the engine.

  As is clear from the above, the cross-sectional area of the fuel passage around the spring retainer 36 is the sum of the cross-sectional area of the central fuel passage 50 and the cross-sectional areas of the plurality of outer fuel passages 51, 51. The pressure loss can be kept small, and a large flow rate of the gas fuel can be passed inside and outside the spring retainer 36, so that the demand for an increase in the fuel flow rate accompanying an increase in engine output can be met.

  In addition, the outer fuel passages 51, 51... Are formed in a groove shape on the outer peripheral surface of the sleeve 38 that supports the spring retainer 36 on the inner side and fits on the inner peripheral surface of the fixed core 5. The sleeve 38 with the passages 51, 51... Can be easily formed, and the productivity is improved.

  On the other hand, since the spring retainer 36 supports the rear end of the return spring 33 by the rear spring seat 35 at the front end thereof as usual, there is no need to change the outer diameter of the return spring 33. Changes can be avoided.

  Further, the front end portion of the sleeve 38 projects forward from the front end of the spring retainer 36, and the rear end portion 33a of the return spring 33 is received in the front end portion of the sleeve 38 so as to restrict the lateral deflection thereof. Therefore, it is possible to prevent the return spring 33 from being displaced from the rear spring seat 35 and to stabilize the operation of the return spring 33. In addition, at the rear end 33 a of the return spring 33, the coil is brought into close contact with each other in order to give rigidity so as to stabilize the support by the rear spring seat 35. In other words, the gas fuel flow from the outer fuel passages 51, 51... To the tapered portion 5a3 is not obstructed.

  Next, a second embodiment of the present invention shown in FIGS. 3A and 3B will be described.

  In the second embodiment, a plurality of outer fuel passages 51, 51... Are formed on the outer periphery of the spring retainer 36 while eliminating the sleeve 38 in the first embodiment. Specifically, the hollow portion 5a of the fixed core 5 is connected to the spring guide hole 5a1 and the rear end of the spring guide hole 5a1 through the taper portion 5a3, and the attachment hole 5a2 (slightly larger in diameter than the spring guide hole 5a1) A spring retainer 36 having a plurality of outer fuel passages 51, 51... Formed in a groove shape on the outer peripheral surface is press-fitted and fixed in the mounting hole 5 a 2. The Since the other configuration is the same as that of the first embodiment, in FIG. 3A and FIG. 3B, portions corresponding to the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  According to the second embodiment, the central fuel passage 50 and the outer fuel passages 51, 51... Can be formed inside and outside the spring retainer 36 without using the sleeve 38 of the first embodiment. Therefore, while simplifying the structure, the pressure loss of the gas fuel is suppressed to a small level, and a large flow rate of the gas fuel can be passed inside and outside the spring retainer 36, so that the fuel flow rate accompanying the increase in the engine output is achieved. We can meet the demand for increase.

  Finally, a third embodiment of the present invention shown in FIGS. 4A and 4B will be described.

  This third embodiment is the same as the second embodiment except that a plurality of outer fuel passages 51, 51... Are formed in a groove shape on the inner peripheral surface of the mounting hole 5 a 2 of the hollow portion 5 a of the fixed core 5. Since the configuration is the same, in FIG. 4A and FIG. 4B, parts corresponding to the second embodiment are denoted by the same reference numerals, and redundant description is omitted.

  Also in the third embodiment, similarly to the second embodiment, the central fuel passage 50 and the outer fuel passages 51, 51... Are formed inside and outside the spring retainer 36 without using the sleeve 38 of the first embodiment. Can do. Therefore, while simplifying the structure, the pressure loss of the gas fuel is suppressed to a small level, and a large flow rate of the gas fuel can be passed inside and outside the spring retainer 36, so that the fuel flow rate accompanying the increase in the engine output is achieved. We can meet the demand for increase.

  The present invention is not limited to the embodiments described above, and various design changes can be made without departing from the scope of the invention. For example, the present invention can be applied to an injection valve for liquid fuel such as gasoline.

I ... Fuel injection valve (Injection valve for gas fuel)
2... Nozzle member 3... Valve housing 5... Fixed core 5 a... Hollow portion 5 a 1 of fixed core... Spring guide hole 5 a 2. ... Valve seat 9 ... Nozzle hole 12 ... Movable core 13 ... Valve 33 ... Return spring 34 ... Front spring seat 35 ... Rear spring Seat 36 ... Spring retainer 50 ... Central fuel passage 51 ... Outer fuel passage

Claims (4)

A nozzle member (2) having a valve seat (7) and a nozzle hole (9), a cylindrical valve housing (3) provided continuously at the rear end of the nozzle member (2), and the valve housing (3) A hollow fixed core (5) connected to the rear end of the rear end, a fuel inlet tube (6) connected to the rear end of the fixed core (5), and the fixed core (5). A fixed spring retainer (36) having a hollow portion serving as a central fuel passage (50) communicating with the inside of the fuel inlet cylinder (6) into the valve housing (3), and accommodated in the valve housing (3) A valve body (13) that opens and closes the nozzle hole (9) in cooperation with the valve seat (7), and is connected to the rear end of the valve body (13), so that the fixed core (5) A movable core (12) facing the suction surface (5b) at the front end, and a rear spring at the front end of the spring retainer (36) A return spring (33) which is contracted between (35) and the front spring seat (34) of the movable core (12) and biases the valve body (13) toward the valve seat (7). The movable core (12) is attracted to the fixed core (5) by the generated magnetic force when energized to surround the fixed core (5), and the valve element (13) is moved to the valve seat ( 7) In a fuel injection valve comprising a coil (22) to be separated from
An outer fuel communicating between the spring retainer (36) and the fixed core (5) in parallel with the central fuel passage (50) in the fuel inlet cylinder (6) into the valve housing (3). A fuel injection valve provided with a passage (51). The fuel injection valve according to claim 1, wherein
The spring retainer (36) is fitted and fixed to the inner peripheral surface of the sleeve (38) fitted and fixed to the inner peripheral surface of the fixed core (5), and the outer fuel passage is connected to the outer peripheral surface of the sleeve (38). A fuel injection valve characterized in that (51) is formed in a groove shape. The fuel injection valve according to claim 2,
The front end of the sleeve (38) protrudes forward from the front end of the spring retainer (36), and the rear end of the return spring (33) is regulated in the front end of the sleeve (38). A fuel injection valve characterized by being received as described above. The fuel injection valve according to claim 1, wherein
The spring retainer (36) is fitted and fixed to the inner peripheral surface of the fixed core (5), and the outer fuel passage (51) is fitted to at least one of the fitting surfaces of the fixed core (5) and the spring retainer (36). A fuel injection valve characterized in that is formed in a groove shape.

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