JP2775797B2 - Check valve - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a check valve provided at a discharge port of a liquid pump, and particularly to a check incorporated in a discharge port of a liquid pump used as a fuel pump of an internal combustion engine for a vehicle. Related to the valve.

2. Description of the Related Art In a vehicle such as an automobile, a fuel pump for pressure-feeding fuel from a fuel tank to a fuel injector maintains a predetermined fuel pressure in a fuel passage from the fuel pump to the fuel injector even after the engine is stopped. The discharge port is provided with a check valve for maintaining the pressure, that is, for maintaining the residual pressure.

Conventionally, this check valve is generally configured as a check valve having a general structure including an annular valve seat portion and a valve body movably provided to selectively seat on the valve seat portion. A fuel pump having a check valve of this type is disclosed, for example, in Japanese Patent Application Laid-Open No. 60-138297 (Japanese Patent Application No. 58-248662).

[Problem to be Solved by the Invention] The valve element of the check valve as described above is opened at a distance from the valve seat during engine operation, that is, during pump operation. In some cases, a swinging phenomenon due to the lateral swing vibration occurs, and when the swinging phenomenon occurs, the fuel discharge pulsation becomes more intense, which causes the generation of abnormal noise.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved check valve for a discharge port of a liquid pump which solves the above-mentioned problems.

Means for Solving the Problems A check valve according to the present invention includes a valve housing having an annular valve seat portion and a valve hole through which a fluid flowing through the valve seat portion passes, and a fluid housed in the valve hole. A valve element that is urged in the axial opening direction by pressure, a coil spring that urges the valve element in the axial valve closing direction, and an inside of the coil spring in the valve hole that extends in the axial direction from the valve housing. A sliding guide cylindrical portion protruding toward the valve seat side, wherein the valve body is disposed at the distal end of the shaft portion, the shaft portion being held slidably in the axial direction by the cylindrical portion. And a hemispherical valve portion seated on the valve seat portion at the axial valve closed position, wherein the valve body is at least axially counter-valved relative to the valve seat portion contact surface area of the valve portion. It is arranged on the seat side and secures a predetermined distance from the valve hole and the valve seat. And a flange-shaped stabilizing portion projecting radially outward from the valve portion and the shaft portion.

That is, the check valve of the present invention has a valve body in which the shaft portion is slidably held in the axial direction in a sliding guide cylindrical portion projecting in the valve hole of the valve housing in the axial direction. In a check valve in which fluid flows in the axial direction along the outer peripheral side of the cylindrical portion of the hole, that is, along the inner peripheral surface of the valve housing, a flange is formed radially outward from the vicinity of the valve portion of the valve body so as not to contact the valve hole or the valve seat. The feature is that the stabilizing part is provided.

[Operation] The pulsating flow of the fuel discharged from the fuel pump causes the valve body to self-excitedly vibrate (swinging phenomenon), thereby making the discharge pulsation of the fuel more intense. However, the provision of the flange-shaped stabilizing portion in the valve body as described above improves the force by the flow of fuel that lifts the valve body against the spring force. ). Further, since the valve element itself has the stabilizing portion, the moment of inertia with respect to the self-excited vibration (swinging phenomenon) increases, and the function of reducing the frequency of the self-excited vibration (swinging phenomenon) is achieved. Therefore, the pulsation of the fuel passing through the check valve can be suppressed to be small, and the noise is less generated.

 Further, the effect of suppressing the swing motion will be described.

This check valve has a valve body in which a shaft portion is slidably held in an axial direction in a sliding guide tube portion provided in a valve hole of a valve housing so as to protrude in an axial direction. A type in which fluid flows in the axial direction along the outer peripheral side, that is, along the inner peripheral surface of the valve housing (hereinafter, referred to as an external flow check valve) is employed.

This external flow type check valve is a check valve of a type in which a shaft portion of a valve body is slidably held on an inner peripheral surface of a valve hole, and a fluid passes through the shaft portion in an axial direction (hereinafter referred to as an internal flow type check valve). (Referred to as a valve), the sliding contact area of the valve body with the valve housing can be significantly reduced, so that the sliding resistance of the valve body is small,
It is difficult for dust and the like to bite into the sliding contact portion, resulting in excellent responsiveness and reliability.

Further, in this external flow type check valve, the shaft portion of the valve element is greatly protruded from the sliding guide tube portion at the initial stage of valve opening, so that the sliding contact area of the shaft portion with respect to the tube portion is further increased. As a result, the external flow type check valve has excellent responsiveness in the initial stage of valve opening, that is, excellent valve opening speed, which is an advantage that it operates reliably even when the difference between the coil spring and the fluid pressure is small. It has become.

However, in the external flow check valve, most of the shaft part protrudes from the cylinder part to the valve seat side in the initial stage of valve opening because the shaft part of the valve body is slidably held by a small diameter cylinder part. State.
As a result, when the fluid passes through the gap between the valve portion and the valve seat portion in a high-speed turbulent state in the early stage of valve opening, the radial dynamic pressure or static pressure applied to the valve portion from the fluid is easily unbalanced. The valve body is periodically displaced in the radial direction by the clearance between the cylindrical portion and the shaft portion with the slidable portion between the cylindrical portion and the shaft portion as a fulcrum. (A swing motion), whereby the discharge fluid pulsates, generating abnormal noise.

The present invention provides a flange-shaped stabilizing portion protruding radially outward from the vicinity of the valve portion of the valve body in a range not in contact with the valve hole or the valve seat, thereby preventing harmful friction and catching of the discharged fluid. Prevent pulsation.

More specifically, the fluid pressure (static pressure) acting on the valve portion is superior to the urging force of the coil spring, and when the valve portion that has been in contact with the valve seat portion is slightly separated from the valve seat portion, the valve hole passes through the gap between the two. Fluid flows into the inside at a high speed, collides with the front surface of the flange-shaped stabilizer, and pushes the valve body strongly in the valve opening direction, whereby the shaft of the valve body is pushed into the cylinder and the shaft in the cylinder. Increases in length.

As a result, since the clearance between the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the shaft portion is constant, the radial displacement of the valve body, that is, the amplitude of the oscillating motion is greatly increased by increasing the length of the shaft portion in the cylindrical portion. The frequency is shifted from the mechanical resonance band of the valve body to a higher frequency, and the swinging motion is well prevented.

In addition, even if the swinging motion occurs, the flange-shaped stable portion is inclined from the radial direction due to this, so the flange-shaped stable portion of the flange-shaped stable portion that is inclined to the opposite side to the valve seat side. The fluid becomes easier to flow in the portion, and the fluid force acting on this portion is reduced, while the fluid is less likely to flow in the portion of the flange-shaped stabilizer that is inclined to the valve seat side. As a result, the fluid force acting on this part is increased, and as a result,
When the collar-shaped stabilizer is tilted, the fluid generates a force for restoring the collar-shaped stabilizer to the original state, and the swinging motion is well suppressed by the recovery moment.

As a result, it is possible to realize an external flow check valve in which the swinging motion is successfully suppressed.

[Embodiment] FIGS. 1 and 2 show a fuel pump employed in this embodiment and a check valve provided therein.

FIG. 2 shows one embodiment of a fuel pump provided with a check valve according to the present invention. A motor housing 1 has a cylindrical shape with lids at both ends and has a pump impeller 2 near one end. The pump impeller 2 is mounted on an output shaft 4 of a pump driving motor 3 incorporated in the pump housing 1 and is driven to rotate by the pump driving motor 3.

The motor housing 1 has a suction port 5 'on the pump cover at the end on the pump impeller 2 side and a discharge port 6' on the bearing holder 6 at the end facing the pump cover. The rotation of the pump impeller 2 sucks fuel from the suction port 5 'and discharges it from the discharge port 6'. A relief valve 7 for adjusting a shutoff pressure is attached to the bearing holder 6, and a check valve 8 is provided inside the discharge port 6 '.
Is incorporated.

As shown in FIG. 1, the check valve 8 includes a pipe portion 10 forming the discharge port 6 side of the pump housing 1 and a pipe portion 10.
A ring-shaped valve seat portion 11 protruding in the center direction from the inner peripheral surface of the valve seat and forming a valve hole in the center, and is movable in the axial direction, that is, in the vertical direction in FIG. The valve body 30 is provided with a stopper 10 fixed to the pipe portion 10 for guiding the valve body 30, and a spring 40 interposed between the stopper 20 and the valve body 30.

The pipe section 10 and the valve seat section 11 constitute a valve housing according to the present invention, and the inner peripheral surface of the pipe section 10 constitutes a valve hole according to the present invention.

The pipe portion 10 has a cylindrical shape on both the inner peripheral surface and the outer peripheral surface, and has a stepped portion 12 for positioning the stopper near the tip on the inner peripheral surface side. The inner peripheral surface of the valve seat 11 is a funnel-shaped inner peripheral surface in which the diameter of the valve body 30 side increases in the direction of the valve element 30, and the inner peripheral surface on the opposite side to the valve element 30 has a constant inner diameter. It has become. The pipe section 10 and the valve seat section 11 are integrally made of glass-containing polyacetal resin.

The stopper 20 is formed by connecting a valve body supporting portion (a cylindrical portion in the present invention) 21 having a cylindrical guide hole 21a and the stopper 20 to a pipe portion 10.
And a rib portion 22 provided so as to be press-fitted and fixed to the inner peripheral surface of the main body.

The valve body support portion 21 has a valve body receiving portion 23 at the tip and a stepped spring receiving seat 24 for supporting the spring 40 at the middle of the outer peripheral surface. The rib portion 22 forms a hollow portion 22a through which fuel can pass, and is configured so that a fixed portion of the outer peripheral surface is in contact with the inner peripheral surface of the pipe portion. It has a ring-shaped flange portion 25 that is positioned by being in contact with each other. The material of the stopper 20 is a polyacetal resin.

The valve body 30 has a shaft portion 31 extending in the axial direction, a hemispherical valve portion 32 provided at one end of the shaft portion 31 and seated on the valve seat portion 11, and a shaft portion of the valve portion 32.
It comprises a flange-shaped stabilizer 33 surrounding the valve portion 32 in the circumferential direction on the 31 side. The shaft portion 31 has a stepped portion 311 at the middle thereof which comes into contact with the valve body receiving portion 23 of the stopper 20. The valve portion 32 has a shaft hole 32a extending in the axial direction from the center of the distal end of the valve body 30. The valve portion 32 is a bowl-shaped seal member 3 having a shaft core portion 341 protruding inward at the center.
With 4. The seal member 34 covers the valve portion 32 by fitting the shaft core portion 341 into the shaft hole 32a. Shaft 3
1. The material of the valve portion 32 and the stabilizing portion 33 is a forged product such as brass, a thermosetting resin, or a thermoplastic resin having a high melting point such as polyphenylene sulfite. The reason for using a resin or the like having a high melting point is that it is necessary to withstand the high temperature at the time of baking and forming the fluorine rubber, which is the material of the seal member 34, on the valve portion 32.

The spring 40 is a coil spring and is interposed between the spring receiving seat surface 24 of the stopper 20 and the base of the stabilizing portion 33 to urge the valve body 30 in a direction in which it comes into contact with the valve seat 11.

Next, the operation of the check valve 8 of this embodiment will be described.

The pulsation on the pump discharge side has a frequency component. This frequency component is due to the rotation of the pump impeller 2 and the valve body.
There are 30 self-excited vibrations (swinging phenomenon). The former is synchronized with the rotation speed of the fuel pump and is approximately 6 at the rotation speed of 4000 rpm.
7 Hz. The latter depends on the spring 40 and the discharge flow rate, but is 200 to 400 Hz when there is no stabilizer 33. The magnitude of the former pulsation is 0.05 kgf / cm ² or less, and this pulsation does not cause the pump discharge side piping to vibrate and generate noise. However, the latter pulsations self-excited vibration of the stabilization part 33 is no valve body (swing phenomenon) when the resonant state 0.2Kgf / cm ² ~0.3Kgf / cm ²
And vibrates the pump discharge side piping, which can be a noise source.

However, when the stabilizing portion 33 is provided in the valve body 30, the force for lifting the valve body 30 against the force of the spring 40 for increasing the force received from the discharged fuel is improved, so that the valve body 30 is held down. ,
Suppresses self-excited vibration (swinging phenomenon). Further, since the valve element 30 itself has the stabilizing portion 33, the moment of inertia with respect to the self-excited vibration (swinging phenomenon) increases, and the effect of reducing the frequency of the self-excited vibration (swinging phenomenon) is also achieved. The above action occurs regardless of whether the stepped portion 311 of the shaft portion 31 of the valve body 30 contacts the valve body receiving portion 23 of the stopper 20. Therefore, the pulsation of the fuel passing through the check valve 8 can be suppressed small, and the occurrence of abnormal noise by inducing vehicle body vibration is small.
FIG. 3 shows the relationship between the area of the stable portion (mm ² ) and the pulsation (kgf / cm ² ).

The shape of the stabilizing portion 33A does not need to be perpendicular to the flow of the fuel as shown in FIG. 4, and may have a tapered surface so as not to interfere with the valve seat portion 11.

Further, as shown in FIG. 5, the shape of the stabilizing portion 33B does not necessarily need to be on the entire circumference of the shaft portion 31, and when the rib 101 is provided on the inner circumferential surface of the pipe portion 10, it may have a notch. .

On the other hand, as shown in FIG. 6, the shapes of the valve portion 32C and the sealing member 34C do not necessarily have to be hemispherical, but may be conical.

[Effect] The check valve of the present invention includes a shaft portion in which the valve body extends in the axial direction,
A check valve having a hemispherical valve portion provided at one end of a shaft portion and seated on a valve seat portion, and a flange-shaped stable portion surrounding the valve portion in the circumferential direction on the shaft portion side of the valve portion. The pulsation of the fuel passing through the vehicle can be suppressed to a small extent, and the occurrence of abnormal noise by inducing vehicle body vibration is small.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the check valve of the present invention. FIG. 2 is a longitudinal sectional view showing one embodiment of a fuel pump incorporating a check valve according to the present invention. FIG. 3 is a graph showing the relationship between the area of the stabilizer and the pulsation. FIG. 4,
5 and 6 are views showing another embodiment of the valve body, respectively. FIG. 4 is a longitudinal sectional view of the valve body, FIG. 5 is a transverse sectional view of the valve body, and FIG. FIG. DESCRIPTION OF SYMBOLS 1 ... Motor housing, 2 ... Pump impeller 3 ... Pump drive motor, 4 ... Output shaft 5 ... Pump cover, 6 ... Bearing holder 5 '... Suction port, 6' ... Discharge port 7 ... relief valve, 8 ... check valve 10 ... pipe section, 101 ... rib 11 ... valve seat section 12, 311 ... stepped section, 20 ... stopper 21 ... valve body support section, 21a ... Guide hole 22 ... rib, 22 a ... hollow 23 ... valve body receiving part, 24 ... spring receiving seat surface 25 ... flange part, 30 ... valve body 31 ... shaft part, 32, 32 c ... Valve 32a: Shaft holes 33, 33A, 33B: Stabilizers 34, 34c: Seal member, 341: Shaft core 40: Spring

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F04B 21/02 F16K 15/06 F16K 47/02

Claims (1)

(57) [Claims] 1. A valve housing having an annular valve seat portion and a valve hole for passing a fluid flowing through the valve seat portion, and a valve housing accommodated in the valve hole and urged in a valve opening direction in the axial direction by fluid pressure. A valve spring, a coil spring for urging the valve body in the axial valve closing direction, and a slide projecting from the valve housing to the axial valve seat side inside the coil spring in the valve hole. A guide cylinder, wherein the valve body is axially slidably held by the cylinder, and the valve is disposed at an end of the shaft and is disposed at an axial valve closing position. A check valve provided with a hemispherical valve portion seated on a seat portion, wherein the valve element is disposed at least on an axially non-valve seat side with respect to a valve seat portion contact surface area of the valve portion, and the valve Outer diameter than the valve part and the shaft part while securing a predetermined interval with respect to the hole and the valve seat A check valve, comprising: a flange-shaped stabilizing portion protruding from a side wall.