JP2003329151A - Valve opening/closing device and fuel injection pump using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem of a conventional valve opening/closing device where a valve body does not sit completely on a body when it is inclined since a sitting seat face of the body and a valve seat face of the valve body are both provided on an almost conic tapered surface. <P>SOLUTION: By forming a valve seat face 23 of a valve body 24 in an almost spherical surface shape, the sealability between the valve seat face 23 and the sitting seat side 21 is surely secured to prevent the blockade leaking even if the valve body 24 is inclinedly seated on a body 22 by clearance of a guide part 29 and a shaft 28. Since the diameter of a sheet is large, elongation in an axial direction of the valve body 24 is suppressed even if the valve seat face 23 is formed in the almost spherical-surface shape. Since the diameter of a sheet is large, a pressure receiving area becomes large to enhance the seating force of the valve body 24 for seating on the body 22, and a high sealability is obtained. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve opening / closing device and a fuel injection pump using the valve opening / closing device.

[0002]

2. Description of the Related Art A valve opening / closing device having a body having a seating seat surface and a valve body having a valve seating surface for seating on and off the seating seat surface is known. In a conventional valve opening / closing device mounted on a fuel injection pump, as shown in FIG. 4 (a), a seating seat surface J2 of a body J1 and a valve seat surface J4 of a valve body J3 are both tapered surfaces having a substantially conical shape. Was installed in.

[0003]

[Problems to be Solved by the Invention] Shaft J of valve body J3
A clearance for sliding the shaft J5 is provided between 5 and the guide portion J6 supporting the shaft J5. Also, this clearance is for shaft J5
There is a possibility that it will spread due to the wear caused by the sliding between the guide part J6 and the guide part. As described above, since the clearance is provided between the shaft J5 and the guide portion J6, when the shaft J5 is tilted by some action, as shown in FIG.
As shown in (b), the valve body J3 is not completely seated on the body J1, and there is a possibility that a blockage leakage may occur in the valve opening / closing device.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is a valve opening / closing device and a valve thereof, which do not cause blockage leakage even when the valve body is seated with the valve body inclined. It is to provide a fuel injection pump using an opening / closing device.

[0005]

[Means for Solving the Problems] [Means for Claim 1] By adopting the means of claim 1, the seating seat surface is provided on a substantially conical taper surface, and the valve seat surface is provided on a substantially spherical shape. Even if the valve body is seated in a tilted manner with respect to the body, the body and the valve body make contact with each other through a ring-shaped line, so that no blockage leakage occurs in the valve opening / closing device.

[Means of Claim 2] By adopting the means of Claim 2, the valve seat surface is provided on a substantially conical taper surface, and the seating seat surface is provided on a substantially spherical surface. Even if the seat is tilted and seated, the body and the valve body come into contact with each other through a ring-shaped line, so that no blockage leakage occurs in the valve opening / closing device.

[Means for Claim 3] If the valve seat surface (or the seating surface) is simply provided in a substantially spherical shape, the bulge thereof lengthens the axial direction of the valve body. Therefore, the means of claim 3 may be adopted to increase the seat diameter at which the seating seat surface and the valve seat surface come into contact with each other. By providing in this way, axial extension of the valve body can be suppressed.

[Means for Claim 4] The means for claim 4 may be adopted to apply a valve opening / closing device having a large seat diameter to a fuel injection pump. By providing in this way,
In the valve opening / closing device mounted on the fuel injection pump, the effects of claims 1 to 3 described above can be obtained. In addition, since the seat diameter is set to be large,
The pressure receiving area of the valve that receives pressure from the pressurizing chamber increases. By increasing the pressure receiving area in this way, the valve body is strongly pressed in the valve closing direction by the high pressure of the pressurizing chamber when the valve is closed. That is, the seating force with which the valve body is seated on the body is increased by increasing the pressure receiving area, and high sealing performance is obtained.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described using examples and modifications. [Embodiment] An embodiment in which the valve opening / closing device is applied to a fuel injection pump will be described with reference to FIGS. The fuel injection pump 1 sends the fuel compressed to a high pressure to the common rail of the fuel injection device, and as shown in FIG. 3, the feed pump 2 (disclosed in the state expanded by 90 ° in the figure),
It is composed of a regulator valve 3, a fuel metering valve 4 (SCV), a high pressure pump 5, and the like.

The feed pump 2 is a trochoid pump which is rotationally driven by a camshaft 6. When the trochoid pump is driven, the fuel sucked from a fuel inlet 7 is supplied to a high pressure pump 5 through a fuel metering valve 4. To do. The camshaft 6 is rotationally driven by the crankshaft of the engine or the like.

The regulator valve 3 is arranged in a fuel passage that connects the discharge side and the supply side of the feed pump 2, and opens when the discharge pressure of the feed pump 2 rises to a predetermined pressure, and the discharge pressure of the feed pump 2 is increased. Does not exceed a predetermined pressure.

The fuel metering valve 4 has its coil energized and controlled by an ECU (abbreviation of engine control unit) (not shown) to control the amount of fuel supplied to the high-pressure pump 5. The fuel pressure on the common rail is controlled by controlling the fuel supply amount to the high-pressure pump 5 by the fuel metering valve 4.

The high-pressure pump 5 is a plunger pump that compresses the fuel supplied from the fuel metering valve 4 to a high pressure and supplies it to the common rail. The plunger 8 is reciprocally driven by the camshaft 6, and the reciprocating motion of the plunger 8 is performed. Intake valve 10 for supplying fuel to the pressurizing chamber 9 whose volume changes by
The valve opening / closing device includes a discharge valve 11 that discharges the fuel compressed in the pressurizing chamber 9 toward the common rail.

The plunger 8 is pressed against a cam ring 13 mounted around the eccentric cam 12 of the cam shaft 6 by a spring 14, so that the cam shaft 6
When is rotated, the plunger 8 reciprocates with the eccentric movement of the cam ring 13. Plunger 8 descends to pressurize chamber 9
When the pressure of is decreased, the discharge valve 11 is closed and
The intake valve 10 is opened and pressure is fed by the feed pump 2,
The fuel metered by the fuel metering valve 4 is supplied into the pressurizing chamber 9. Conversely, when the plunger 8 rises and the pressure in the pressurizing chamber 9 rises, the suction valve 10 closes. Then, when the pressure pressurized in the pressure chamber 9 reaches a predetermined pressure, the discharge valve 11 is opened and the high pressure fuel pressurized in the pressure chamber 9 is supplied toward the common rail.

As shown in FIG. 3, the suction valve 10 has a structure assembled on the top of the pressurizing chamber 9. Therefore, the intake valve 10 is a valve opening / closing device using a valve body 24 (which will be described later) generally in the shape of an umbrella in order to reduce the size of the high-pressure pump 5 in the radial direction (stroke direction of the plunger 8). Is used.

Next, the structure of the intake valve 10 (corresponding to a valve opening / closing device) will be described with reference to FIGS. The intake valve 10 is shown in FIG. 1A, and includes a body 22 having a seating seat surface 21 and a valve body 24 having a valve seating surface 23 for seating on and off the seating seat surface 21. And a return spring 25.

The body 22 is fixed to the top of a cylinder 26 slidably supporting the plunger 8 by a lid member 27 or the like as shown in FIG. This body 22
Is the shaft 2 of the valve body 24 as shown in FIG.
A guide portion 29 for slidably supporting 8 is provided. Also,
A valve chamber 30 that is closed by the valve body 24 is formed in the body 22. This valve chamber 30 has a fuel passage 3
1 communicates with the fuel metering valve 4, and the fuel metering valve 4
The fuel metered in is introduced into the valve chamber 30.

The valve body 24 is a shaft 28 having a rod shape.
The shaft 28 is provided with a guide portion 29 of the body 22.
It is slidably supported by. Return spring 2
5 is a washer 3 attached to the upper end of the shaft 28
2 is a compression coil spring mounted between the body 2 and the body 22 and biases the valve body 24 in the valve closing direction to give the valve body 24 a set load for opening the valve. The valve opening pressure of the valve element 24 is determined by the set load of the return spring 25 and the seat diameter.

In the intake valve 10 having the above-mentioned structure, the plunger 8 descends and the pressure in the pressurizing chamber 9 decreases, so that the valve chamber 30
When the pressure difference between the pressure chamber 9 and the pressure chamber 9 exceeds the valve opening pressure, the valve is opened, and the fuel metered by the fuel metering valve 4 flows into the pressure chamber 9. When the plunger 8 starts rising, the suction valve 10 closes.
Then, as the plunger 8 rises, the pressure in the pressurizing chamber 9 is applied to the lower surface of the valve body 24, and the valve body 24 is pressed in the valve closing direction, so that compression leakage of fuel in the intake valve 10 is prevented. Since the shaft 28 of the valve body 24 is slidably supported by the guide portion 29 of the body 22, the valve body 24 may tilt due to the clearance between the shaft 28 and the guide portion 29. Therefore, in this embodiment, the following configuration is adopted to avoid the problem caused by the inclination of the valve body 24.

As shown in FIG. 1A, in this embodiment, the seating seat surface 21 of the body 22 is provided as a substantially conical tapered surface. On the other hand, the valve seat surface 23 of the valve body 24 is
Substantially spherical shape (R surface shape) that bulges toward the seat 21 side
It is provided in. By providing in this way, FIG.
As shown in (b), even if the valve body 24 is seated with the body 22 tilted, the body 22 and the valve body 24 contact each other with a ring-shaped line, so that the valve seat surface 23 and the seated seat surface 21
There is no occlusion leak between and.

Here, in contrast to the conventional valve body shown by the broken line in FIG. 2 (a), if the valve seat surface 23 is simply provided in a substantially spherical shape as shown by the solid line in the figure, the valve body will be bulged to form the valve body. The axial direction of 24 becomes long (see symbol H in the figure).
Therefore, in comparison with the conventional valve body shown by the broken line in FIG. 2B, as shown by the solid line in FIG.
The seating surface 21 and the valve seat surface 2 with a large diameter.
The sheet diameter (see reference numeral L in the figure) with which the sheet 3 and 3 contact each other is increased. By providing in this way, as apparent from comparison with the conventional valve body 24 shown by the broken line in FIG. 2 (b), the valve body 24 of this embodiment shown by the solid line in the figure is extended in the axial direction. Can be suppressed.

Further, as the seat diameter increases, the contact area between the seating seat surface 21 and the valve seat surface 23 increases and the surface pressure of the contact surface decreases, but at the same time, the pressure in the pressurizing chamber 9 is received. The pressure receiving area of the valve body 24 becomes large, and the valve body 24 is
The seating power to sit on 2 increases. In this case, the effect of increasing the seating force for seating the valve body 24 on the body 22 by increasing the pressure receiving area of the valve body 24 is greater. Therefore, the seating force of the valve body 24 is higher than that of the conventional intake valve 10, and a high sealing property can be obtained when the valve is closed.

(Effect of Embodiment) In the fuel injection pump 1 of this embodiment, the valve seat surface 23 of the valve body 24 is provided in a substantially spherical shape so that the valve body 24 can be moved by the clearance between the guide portion 29 and the shaft 28. Even if the vehicle is seated in an inclined manner with respect to the body 22, the sealing property between the valve seat surface 23 and the seat seat surface 21 is reliably maintained, and no occlusion leakage occurs.

Further, since the seat diameters of the valve body 24 and the body 22 are made large, even if the valve seat surface 23 of the valve body 24 is provided in a substantially spherical shape, the axial extension of the valve body 24 is suppressed,
As a result, the problem that the axial dimension of the intake valve 10 becomes large is avoided. That is, as described above, the intake valve 10 can be made compact in which the sealing performance is maintained even when the valve body 24 is seated in an inclined state. For this reason, it is possible to reduce the size in the radial direction (stroke direction of the plunger 8) of the fuel injection pump 1 equipped with the intake valve 10 in which the sealing property is maintained even if the valve body 24 is seated in an inclined state.

Further, since the seat diameters of the valve body 24 and the body 22 are made large, the pressure receiving area of the valve body 24 receiving the pressure from the pressurizing chamber 9 becomes large and the valve body 24 is seated on the body 22. Power increases. As a result, the plunger 8
When the compression chamber 9 is compressed, the suction valve 10 exhibits a high sealing property, so that the pressure chamber 9 can be increased in pressure and the fuel injection pump 1 can be increased in pressure.

[Modification] In the above-described embodiment, an example in which the seating seat surface 21 is provided on the substantially conical tapered surface and the valve seat surface 23 is provided on the substantially spherical surface has been shown. May be provided on a substantially conical taper surface, and the seating seat surface 21 may be provided on a substantially spherical shape that bulges toward the valve seat surface 23 side. Even if it is provided in this way, it is possible to obtain the same effect as that of the above embodiment.

In the above embodiment, the present invention is applied to the fuel injection pump 1 in which a plurality of plungers 8 are arranged around the cam shaft 6, but the present invention is applied to other types of fuel injection pumps. You may apply. Further, an example in which the present invention is applied to the intake valve 10 of the fuel injection pump 1 that supplies high-pressure fuel to the common rail has been shown. However, all the umbrella-shaped valve bodies and seating seat surfaces on which the valve bodies are seated are provided. The present invention may be applied to a valve opening / closing device.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an intake valve (example).

FIG. 2 is an explanatory diagram illustrating a relationship between a bulge of a valve seat surface and an axial length.

FIG. 3 is a sectional view of a fuel injection pump.

FIG. 4 is a cross-sectional view of a valve opening / closing device (conventional example).

[Explanation of symbols]

1 Fuel injection pump 8 Plunger 9 Pressurization chamber 10 Intake valve (valve opening / closing device) 21 Seating surface 22 body 23 valve seat surface 24 valve

Claims (4)

[Claims] 1. A valve opening / closing device comprising: a body having a seating seat surface; and a valve body having a valve seating surface that seats on and off the seating seat surface, wherein the seating seat surface is substantially A valve opening / closing device provided on a conical tapered surface, wherein the valve seat surface is provided in a substantially spherical shape that bulges toward the seating seat surface side. 2. A valve opening / closing device comprising a body having a seating seat surface, and a valve body having a valve seating surface for seating on and off the seating seat surface, wherein the valve seat surface is substantially A valve opening / closing device provided on a conical tapered surface, wherein the seating seat surface is provided in a substantially spherical shape that bulges toward the valve seat surface side. 3. The valve opening / closing device according to claim 1 or 2, wherein a seat diameter for contacting the seating seat surface and the valve seat surface is increased. 4. A plunger that repeats expansion and contraction of the pressurizing chamber by reciprocating, and a valve that opens when the plunger expands the pressurizing chamber to guide fuel into the pressurizing chamber, and the plunger. The valve opening / closing device according to claim 3, which closes when the pressure chamber is reduced.