JP3767111B2 - Injection valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an injection valve that opens a valve by the pressure of a supplied fluid and injects the fluid, and relates to a technique that improves responsiveness during injection and facilitates assembly and adjustment with a simple structure.
[0002]
[Prior art]
Conventionally, this type of injection valve is, for example, provided in an intake portion of an engine to create an air-fuel mixture for driving the engine, and opens the valve body by the pressure of pressurized fuel and injects fuel. There is a fuel injection valve.
FIGS. 5A and 5B are views for explaining a cross-sectional configuration of the fuel injection valve 101. FIG. 5A shows the overall configuration, and FIG. It is the figure which expanded the nozzle tip part.
[0003]
Fuel that is pressurized to a predetermined pressure in accordance with the fuel injection timing is supplied to the fuel injection valve 101 through the fuel supply pipe 102.
[0004]
The fuel supply pipe 102 is provided with a fixed flange portion 102a protruding in a flange shape at the tip thereof, and the connection hole 103a provided at one end portion of the connection sleeve 103 is sealed by an O-ring 104 and a fixed plug 105. Fixed.
[0005]
A cylindrical body 106 of the fuel injection valve 101 is sealed and fixed in a connection hole 103b provided at the other end of the connection sleeve 103 by a method such as press fitting. A sleeve 107 is fitted and fixed to the inner periphery of the injection side of the body 106, and a valve seat 108 is fitted and fixed to the inner periphery of the sleeve 107.
[0006]
A valve body 109 including a spherical steel ball valve body 109a that contacts the valve seat surface 108a and a rod 109b connected to the valve seat surface 108a is inserted into the valve seat 108.
[0007]
A spring retainer 109c is fixed to the opposite side of the rod 109b to the steel ball valve body 109a. Then, the spring retainer 109c is urged upward in the drawing by the spring 110 having the end portion on the fuel supply pipe 102 side of the sleeve 107 as a fixed pedestal portion, so that the closed state of the steel ball valve body 109a is maintained. I have to.
[0008]
A nozzle plate 111 having a fuel injection hole 111 a for atomizing and injecting fuel at the tip is attached to the end of the valve seat 108 on the injection side. Reference numeral 112 denotes a cylindrical nozzle cap that protects the tip of the fuel injection valve 101.
[0009]
The operation of the fuel injection valve 101 will be briefly described. The fuel supplied at a predetermined pressure by the fuel supply pipe 102 is supplied from the connecting chamber 113 in which the spring 110 is accommodated, the sleeve 107, and the passage 108b in the inner diameter portion of the valve seat 108. Then, the steel ball valve body 109a is guided by a predetermined pressure, and the steel ball valve body 109a is pressed and opened by a predetermined pressure, and is injected from the fuel injection hole 111a.
[0010]
The injection timing and the injection amount according to the engine state are determined by a control unit (not shown). The fuel is supplied to the engine with intermittent pressure waves by means of a fuel pressure pump, a pressure regulator that adjusts the pressure of the pressurized fuel within a certain range, and a solenoid valve that adjusts the flow rate. The fuel is distributed and supplied to a predetermined number of fuel supply pipes 102 corresponding to the type and the number of cylinders, and injected from each fuel injection valve.
[0011]
Therefore, the fuel injection valve 101 is opened by the pressure of the supplied fuel. When the fuel is below a predetermined pressure, the fuel is not injected by holding the valve in the valve closing direction, and the fuel injection valve 101 Only when the pressure is high, the valve is opened to inject fuel.
[0012]
[Problems to be solved by the invention]
However, further improvement is desired for the fuel injection valve 101 having such a configuration in order to maintain the competitiveness of the product by solving the following problems.
[0013]
a) The structure of the fuel injection valve 101 is complicated and large.
[0014]
b) After assembling the valve body 109, the valve seat 108 is press-fitted into the sleeve 107 and the rod 109b and the spring 110 are mounted in combination, and then the tip of the rod 109b and the steel ball valve body 109a are connected to the valve seat surface of the valve seat 108. Since the welding is performed in the vicinity of 108a, the assembly process is complicated and difficult, and the assemblability is low.
[0015]
c) The constituent members that become the movable portion when the valve is opened are the spring 110, the spring retainer 109c, the rod 109b, and the steel ball valve body 109a, and the mass of the movable portion increases. Therefore, the responsiveness at the time of pressure application deteriorates, and the injection flow rate characteristic particularly at a short pulse width is deteriorated.
[0016]
By the way, in order to solve the above problem, it is conceivable to first simplify the configuration of the fuel injection valve. Therefore, referring to US Pat. No. 4,932,374, as shown in FIG. 6, there is one that uses a diaphragm to constitute a nozzle portion 200 of an injection valve.
[0017]
6A is a cross-sectional configuration diagram of the main part of the nozzle unit 200, FIG. 6B is a view taken along arrow V101-V101 in FIG. 6A, and FIG. 6C is a diagram in which fuel is injected from the nozzle unit 200. It is a figure explaining the state which exists.
[0018]
The configuration of the nozzle unit 200 includes a cylindrical sleeve 201 that is a closed end 203 having a communication hole 202 in the center at one end 201a, and a thin covering the outside of the closed end 203 of the cylindrical sleeve 201. It is comprised from the diaphragm 205 which consists of a disk-shaped member.
[0019]
The diaphragm 205 includes a plurality of injection holes 206 at an outer position that does not face the communication hole 202. When a predetermined pressure of fuel is supplied to the sleeve 201, the diaphragm 205 is deformed so as to bulge outward as shown in FIG. 6C due to the supply pressure of the fuel, and is injected along the path indicated by the arrow A101. Fuel is injected from the hole 206.
[0020]
However, in the configuration of the nozzle unit 200, the communication hole 202 is closed when the fuel is not injected by the central region 205a of the diaphragm 205, so that it is difficult to achieve a complete valve closing state, and fuel leakage is easily performed. There is a concern that it will occur.
[0021]
Further, since the valve opening pressure becomes the pressure of the fuel that deforms the diaphragm 205 from the communication hole 202, it is difficult to easily change the valve opening pressure at the time of assembly or after assembly, and the variation in the valve opening pressure is large. In the configuration as it is, it cannot be used as an alternative configuration of the fuel injection valve 101 in FIG.
[0022]
The present invention has been made to solve the above-described problems of the prior art, and its object is a simple configuration that enables downsizing and improved manufacturability such as assembly and adjustment workability. It is an object of the present invention to provide an injection valve that achieves the above and improving functional characteristics such as injection responsiveness and fuel leakage prevention.
[0023]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides:
A valve body that comes into contact with a seat surface formed at one end of a cylindrical valve seat member, and an urging means that urges the valve body toward the seat surface to make the valve closed;
An injection valve in which the valve element is opened away from the seat surface against the urging force of the urging means by the pressure of the fluid supplied to the valve seat member;
The biasing means is a leaf spring having a support arm extending toward the valve body, an opening along the contour of the support arm, and an injection hole for injecting fluid,
A rubber-like elastic film for preventing fluid leakage from the opening of the leaf spring is provided.
[0024]
Thereby, the valve body is urged by the support arm by the leaf spring. When the valve element opens due to the pressure of the fluid, the fluid that flows out from the gap between the seat surface and the valve element is ejected to the outside through the ejection hole provided in the leaf spring.
[0025]
Further, the leaf spring is disc-shaped, and the support arm is formed by a plurality of cuts from the central portion toward the outer periphery,
It is also preferable that the rubber-like elastic film covers at least one surface of the leaf spring.
[0026]
As a result, the support arm can stably urge the valve body, and the rubber-like elastic film can cover the notch for forming the support arm.
[0027]
It is also preferable that a leaf spring holding member is provided that enables adjustment of the biasing force of the support arm to the valve body by changing the position of the leaf spring with respect to the seat surface.
[0028]
Thereby, the urging force of the support arm to the valve body can be adjusted, and the valve opening pressure of the injection valve can be adjusted.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
An injection valve according to an embodiment to which the present invention is applied will be described with reference to FIG. The injection valve 1 is provided in an intake portion of the engine, for example, to create an air-fuel mixture for driving the engine, and has an injection timing and an injection amount according to the state of the engine determined by a control unit (not shown). In this way, it is used as a fuel jet as a fluid.
[0030]
In addition, the injection valve 1 when used in such applications is pressurized to a constant pressure by a fuel pressurizing pump and a pressure regulator (not shown) and intermittently by an electromagnetic valve that opens and closes at a predetermined timing. A fuel with a strong pressure wave is supplied. And the injection valve 1 opens according to the pressure of fuel, and injects fuel.
[0031]
(Embodiment 1)
FIG. 1A is a cross-sectional configuration explanatory view of an injection valve 1 according to a first embodiment to which the present invention is applied, and FIG. 1B is an enlarged view of a nozzle tip portion of FIG. 1 (c) is a view of FIG. 1 (b) as viewed from the direction of arrows V1-V1.
[0032]
In the injection valve 1, a fuel supply pipe 3 is connected and fixed to one end portion (upper end side in the figure) of a cylindrical valve seat member 2 with an O-ring 4 and a plug 5 while maintaining hermeticity. The fuel is introduced into the seat surface 2b formed at the other end through the inner diameter portion 2a of the valve seat 2 by the fuel supply pipe 3.
[0033]
A steel ball valve body 6 is in contact with the seat surface 2b, and the flow path is closed when the steel ball valve body 6 is closed.
[0034]
The steel ball valve body 6 is urged and supported in the valve closing direction by a leaf spring 7 as urging means. The leaf spring 7 has a disk shape, and both surfaces are covered with a thin rubber-like elastic film 8.
[0035]
As shown in FIG. 2A, the leaf spring 7 has a circular punched portion 7a at the center of the disk, and four fan-shaped cuts 7b (a plurality) are formed from the circular punched portion 7a toward the outer periphery. Has been. And between the hypotenuses 7c (plurality) of the adjacent sector-shaped cuts 7b is a support arm 7d (plurality) that urges the steel ball valve body 6.
[0036]
Each support arm 7d is bent so that a tip end portion 7f (a part of the outline of the circular punched portion 7a) rises in the axial direction from the outer peripheral end portion 7e of the leaf spring 7 toward the steel ball valve body 6, It corresponds to the valve opening stroke of the valve body 6.
[0037]
Further, in the region between the outer peripheral end 7e and the base of the support arm 7d, two injection holes 7g for injecting fuel are provided opposite to each other in this embodiment. Although the injection hole 7g can be provided in the support arm 7d, it is preferable to provide the injection hole in a region other than the support arm 7d in order to stabilize the injection direction and the injection shape.
[0038]
The rubber-like elastic film 8 is integrally formed on both surfaces of the leaf spring 7 by a method such as vulcanization molding or adhesive bonding, and covers the circular punched portion 7a or the fan-shaped cut 7b as the opening of the leaf spring 7. Yes. However, only the periphery of the injection hole 7g does not exist as the opening 8a.
[0039]
Accordingly, as shown in FIG. 1 (c), when viewed from the nozzle tip side of the injection valve 1, the rubber-like elastic film 8 indicated by the oblique lines appears on the surface, and the leaf spring 7 is hidden inside. A portion other than the injection hole 7g located in the opening 8a cannot be seen directly.
[0040]
The plate spring 7 is supported at the outer peripheral end portion 7e (covered by the rubber-like elastic film 8) by an inward flange portion 9a of the nozzle sleeve 9 as a plate spring holding member. Adjustment of the urging force (set load) with respect to the ball valve body 6 can be performed by adjusting the relative positional relationship between the nozzle sleeve 9 and the valve seat member 2 in the axial direction. In this embodiment, the position when the nozzle sleeve 9 is press-fitted into the valve seat member 2 during assembly is determined.
[0041]
The joint between the nozzle sleeve 9 and the leaf spring 7 is sealed by a method such as caulking, and the fuel that has flowed into the gap 10 between the end surface 2c of the valve seat member 2 and the leaf spring 7 is from other than the injection hole 7g. There is no leakage. Accordingly, the gap 10 is a chamber sealed by the end surface 2 c of the valve seat member 2, the leaf spring 7 and the axial wall 9 b of the nozzle sleeve 9.
[0042]
According to the injection valve 1 having such a configuration, the steel ball valve body 6 urged in the valve closing direction by the leaf spring 7 is injected against the urging force by the pressure of the fuel pressurized and supplied at the injection timing. When the valve is opened by moving in the direction (downward in the figure), fuel is supplied from the seat surface 2b, passes through the gap 10, and is injected from the injection hole 7g.
[0043]
The pressure of the supplied fuel is low except at the injection timing, and the steel ball valve body 6 is urged by the leaf spring 7 to be in a closed state.
[0044]
Therefore, the urging | holding holding | maintenance to the seat surface 2b of the steel ball valve body 6 can be performed by the leaf | plate spring 7 of a simple structure, and the structure of the injection valve 1 becomes simple and can be reduced in size. As a result, assembly and set load adjustment can be easily performed, and productivity can be improved.
[0045]
Further, by using the steel ball valve body 6 as the valve mechanism, there is little fuel leakage when the valve is closed, and when the valve is opened, a smooth flow is obtained without impeding the flow of fuel passing through the seat surface. Furthermore, since the urging means is constituted by the leaf spring 7, the configuration and mass of the movable part can be reduced, and the functional characteristics such as injection response can be improved.
[0046]
When it is necessary to change the set load or urging stroke of the leaf spring 7 with respect to the steel ball valve body 6, the thickness of the support arm 7d is changed, or as shown in FIG. It is also possible to form a U-shaped support arm 7d ′ by a cut groove 7b ′ that is bent in the circumferential direction from the circular punched portion 7a ′. Also in this case, the cut groove 7b ′ serving as the opening is covered with the rubber-like elastic film, and fuel does not leak from the cut groove 7b ′.
[0047]
(Embodiment 2)
FIG. 3 is a cross-sectional configuration diagram of a main part showing the configuration of the nozzle tip of the injection valve 21 according to the second embodiment. In this figure, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0048]
In this embodiment, a rubber-like elastic member 28 covering the surface of the leaf spring 27 is formed only on the surface opposite to the steel ball valve body 6.
[0049]
Therefore, since the steel ball valve body 6 is in direct contact with the support arm 27d of the leaf spring 27, the rubber-like elastic member 28 in the portion that comes into contact with the steel ball valve body 6 due to long-term use is deteriorated, deformed or damaged. It is possible to prevent the problems involved.
[0050]
That is, when the set load is stabilized, the valve opening pressure is stabilized, and the injection shape of the injected fuel can be made constant. Other operations and effects are the same as those of the injection valve 1 of the first embodiment.
[0051]
(Embodiment 3)
FIG. 4 is a cross-sectional configuration diagram of a main part showing the configuration of the nozzle tip of the injection valve 31 according to the third embodiment. In this figure, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0052]
In the injection valve 31 of the third embodiment, the bending direction of the leaf spring 37 that urges the steel ball valve body 6 is a cross section that swells in the injection direction, contrary to the first and second embodiments. It has a shape.
[0053]
A rubber-like elastic member 38 that covers the surface of the leaf spring 37 is formed on the entire surface opposite to the steel ball valve body 6 and on the outer peripheral portion of the surface of the steel ball valve body 6. The injection hole 37g is formed on the support arm 37d at a position close to the sheet surface 2b.
[0054]
Thus, by setting the bending direction of the leaf spring 37 outward, the volume of the gap 10 ′ between the end surface 2 c of the valve seat member 2 and the leaf spring 37 can be set small, and the amount of fuel dead soak Can be reduced. In addition, since the injection hole 37g is provided in the region where the pressure loss is small, it is possible to obtain a well-formed fuel injection shape.
[0055]
【The invention's effect】
According to the present invention, the urging and holding of the valve body can be performed by the leaf spring having a simple configuration, and the configuration of the injection valve can be simplified and the size can be reduced.
[0056]
As a result, assembly and set load adjustment can be easily performed, and productivity can be improved.
[0057]
Further, since the valve body is closed as the valve mechanism, there is little fuel leakage when the valve is closed, and the structure and mass of the movable part can be reduced and the injection response can be improved.
[Brief description of the drawings]
FIG. 1 (a) is a cross-sectional configuration explanatory view of an injection valve according to a first embodiment, FIG. 1 (b) is an enlarged view of the nozzle portion, and FIG. 1 (c) is an arrow view V1. FIG.
FIG. 2 is a view of a leaf spring.
FIG. 3 is an enlarged cross-sectional view of a nozzle portion of an injection valve according to a second embodiment.
FIG. 4 is an enlarged cross-sectional view of a nozzle portion of an injection valve according to a third embodiment.
FIG. 5 is an explanatory diagram of a cross-sectional configuration of a conventional injection valve.
FIG. 6 is a cross-sectional configuration explanatory diagram of a nozzle portion of a conventional injection valve.
[Explanation of symbols]
1, 21, 31 Injection valve 2 Valve seat member 2a Inner diameter portion 2b Seat surface 3 Fuel supply pipe 4 O-ring 5 Plug 6 Steel ball valve element (valve element)
7 Leaf spring (biasing means)
7a Circular punched portion 7b Fan-shaped cut 7c Slope side 7d Support arm 7e Outer peripheral end portion 7f End portion 7g Injection hole 8 Rubber elastic film 8a Opening portion 9 Nozzle sleeve (leaf spring holding member)
9a Flange 9b Axial wall 10 Clearance

Claims (3)

A valve body that comes into contact with a seat surface formed at one end of a cylindrical valve seat member, and an urging means that urges the valve body toward the seat surface to make the valve closed;
An injection valve in which the valve element is opened away from the seat surface against the urging force of the urging means by the pressure of the fluid supplied to the valve seat member;
The biasing means is a leaf spring having a support arm extending toward the valve body, an opening along the contour of the support arm, and an injection hole for injecting fluid,
An injection valve comprising a rubber-like elastic membrane for preventing fluid leakage from the opening of the leaf spring. The leaf spring is disk-shaped, and its support arm is formed by a plurality of cuts from the center toward the outer periphery,
The injection valve according to claim 1, wherein the rubber-like elastic film covers at least one surface of the leaf spring. 3. The injection valve according to claim 1, further comprising a leaf spring holding member capable of adjusting a biasing force of the support arm to the valve body by changing a position of the leaf spring with respect to the seat surface.

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