JPH08247327A - Flow rate control valve - Google Patents

Abstract

PURPOSE: To provide a flow rate control valve with a small difference between a valve opening response time from a closed valve state to an opened valve state and a valve closing response time from the opened valve state to the closed valve state. CONSTITUTION: A fixed iron core 5 excited by a solenoid 3 is provided on the upper part of the bobbin 2 of a duty control valve 1, and a valve chamber 8 for giving connection between a flow-in passage 6 and a flow-out passage 7 is formed in the lower part of the fixed iron core 5. A valve body 9 is housed in the valve chamber 8 vertically movably and the valve body 9 is energized by a return spring 11 to a valve seat part 10 provided in the lower part of the valve chamber 8. A tapered suction part 12 is formed on the bottom end part of the fixed iron core 5 and a slant surface 13 inclining by a taper angle θ relative to the moving direction of the valve body 9 is formed on the side surface of the suction part 12. A recessed part 14 matching the suction part 12 is provided on the upper end part of he valve body 9 and an opposing surface 15 is formed in parallel to the slant surface 13 is formed on the internal wall of the recessed part of 14. A through hole 16 is provided in the center of the valve body 9, and shock absorbing rubber 17 is fitted to the inside of the through hole 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control valve for controlling the flow rate of auxiliary air supplied to an engine, for example.

[0002]

2. Description of the Related Art Conventionally, an automobile engine is provided with an auxiliary air system for supplying auxiliary air. The auxiliary air system changes the supply amount of the auxiliary air according to the operating condition of the engine, and as shown in FIG. 9, by changing the ratio of the ON time and the OFF time of the drive signal, A duty control valve 70 is used as a flow rate control valve that controls the flow rate of the auxiliary air.

The duty control valve 70 includes a bobbin 71 made of a non-magnetic material and a coil 72 wound around the bobbin 71.
And molding the coil 72 and the coil 7
And a mold part 74 integrally forming the second connection terminal 73. A fixed iron core 75, which is excited by the coil 72, extends vertically in the bobbin 71, and a valve chamber connecting an inflow path 76 and an outflow path 77 to a lower end of the fixed iron core 75. 78 is formed. The valve chamber 78 accommodates a vertically movable cylinder-shaped valve body 81 having a valve portion 79 at its lower end and a cushioning rubber 80 at its upper end. Return spring 8
It is urged toward the tubular valve seat portion 83 formed in the valve chamber 78 by the valve 2.

That is, the duty control valve 70
Is the valve portion 7 of the valve body 81 when the coil 72 is not energized.
9 is seated on the valve seat portion 83 to be in a valve closed state, and when energized, the valve body 81 moves upward due to the magnetization of the fixed iron core 75,
The valve is opened.

[0005]

However, in the conventional flow control valve 70, as shown in FIG. 10, the lower end surface of the fixed iron core 75 and the valve body 81 sucked by the fixed iron core 75. Is maintained perpendicular to the moving direction of the valve body 81, and the magnetic gap L1 from the lower end surface of the fixed iron core 75 to the upper end surface of the valve body 81 is equal to the moving amount of the valve body 81. Accordingly, the amount of movement changes by the same amount. Therefore, when attracting the valve body 81 in the valve closed state, the magnetic force of the fixed iron core 75 excited by the coil 72 gradually increases, but as shown in FIG. 4, the valve body 81 is fixed. The magnetic gap L1 becomes smaller and the magnetic attraction force becomes larger as it approaches the iron core 75 (as it approaches the valve opening position).

On the other hand, when the coil 72 is de-energized and the valve body 81 sucked by the fixed iron core 75 is pushed back downward by the spring force of the return spring 82, the fixed iron core 75 is excited. Has a residual magnetic force, which gradually weakens. However, since the magnetic gap L1 from the lower end surface of the fixed iron core 75 to the upper end surface of the valve body 81 at this time is the narrowest in the stroke range of the valve body 81 near the valve opening position, as shown in FIG. , The magnetic attraction force acts greatly. As a result, as shown in FIG. 6, the valve closing response time during the transition of the valve body 81 from the valve opening position to the valve closing position is longer than the valve opening response time during the transition from the valve closing position to the valve opening position. Therefore, the valve closing response delay obtained by subtracting the valve closing response time from the valve opening response time becomes large. Therefore, compared with an ideal duty control valve in which the valve opening response time and the valve closing response time match, it is expected that the amount of outflowing air will increase.

FIG. 11 shows a measurement result obtained by measuring the outflow amount of air at this time by changing the control signal applied to the duty control valve 70 from the duty ratio of 0% to 100%. Air begins to escape between the 4% and 5% ratios. At this time, the outflow rate changes from 0 to 2.5 (l / min) at once, and it is possible to confirm the JUMP-UP phenomenon in which the outflow rate jumps up at once due to the valve closing response delay. This JUMP-UP phenomenon deteriorates the controllability of the outflow amount with respect to the control signal, and may adversely affect the drivability of the engine.

The present invention has been made in view of the above-mentioned conventional problems, and has a valve opening response time from a valve closed state to a valve open state and a valve open response time from a valve open state to a valve close state. An object of the present invention is to provide a flow control valve having a small difference from the valve closing response time.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, in the present invention, a control valve body is slidably fitted in a valve chamber and is seated on a valve seat provided in the valve chamber. The valve body energized by the solenoid is attracted and moved to a fixed iron core excited by a solenoid, and the valve is fully opened and fully closed by changing the ratio of ON time and OFF time of a drive signal applied to the solenoid. In a flow rate control valve that allows fluid to flow while repeating the above, a cushioning member that penetrates in the moving direction of the valve body is provided in the valve body, and the cushioning member is seated on the valve seat when the valve is closed, and when the valve is opened. While contacting the cushioning member with the suction portion, an inclined surface that is inclined with respect to the moving direction of the valve body is formed in the suction portion of the fixed iron core, and the inclined surface is formed in the portion to be sucked of the valve body. Formed a facing surface facing the

[0010]

In the above construction, the suction portion of the fixed iron core is formed with an inclined surface which is inclined with respect to the moving direction of the valve body, and the suctioned portion of the valve body sucked by the fixed iron core is the inclined surface. Since the facing surface is formed to face the inclined surface, and the facing surface is attracted to the inclined surface, the magnetic gap between the fixed iron core and the valve body is the distance from the facing surface to the inclined surface. Therefore, when the valve body moves by a predetermined amount, the amount of change in the magnetic gap is represented by L, the amount of change in the valve gap, S, the amount of change in the magnetic gap, and S If θ, then S = L × sin θ, and the magnetic gap change amount S is smaller than the valve body movement amount L.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the duty control valve 1 as the flow rate control valve according to the present embodiment has a drive signal ON.
The air flow rate is changed by changing the ratio of the time to the OFF time, and the bobbin 2 as a control valve body made of a non-magnetic material, the solenoid 3 wound on the upper part of the bobbin 2, The solenoid 3 is molded, and a molding portion 4 is integrally formed with a connection terminal of the solenoid 3.

A fixed iron core 5 excited by the solenoid 3 extends vertically in the upper part of the bobbin 2, and an inflow passage 6 and an outflow passage 7 are provided at the lower end of the fixed iron core 5. A valve chamber 8 that connects with is formed. A cylindrical valve body 9 is housed in the valve chamber 8 so as to be vertically movable,
This valve body 9 is provided with the outflow passage 7 provided below the valve chamber 8.
Is urged by a return spring 11 toward a cylindrical valve seat portion 10 communicating with the.

At the lower end of the fixed iron core 5, as shown in FIG. 2, there is formed a taper-like suction portion 12 whose outer diameter is reduced in diameter toward the lower end.
A circular surface 12a having a diameter A smaller than the outer dimension of the suction portion 12 on the base end side is formed at the tip of the. Further, the taper angle θ of the suction portion 12 is set to 17.5 degrees, and the inclined surface 13 that is inclined by the taper θ with respect to the moving direction of the valve body 9 is formed on the side surface of the suction portion 12. Has been done.

On the other hand, in the upper end portion of the valve body 9, a concave portion 1 forming a mortar-shaped sucked portion that fits the suction portion 12 is formed.
4 is provided, and an opposed surface 15 parallel to the inclined surface 13 is formed on the inner wall of the recess 14. A through hole 16 having an inner diameter B larger than the diameter A of the circular surface 12a penetrating in the moving direction of the valve body 9 is provided at the center of the valve body 9. The magnetic field from the circular surface 12a of the suction part 12 is not influenced.

A shock absorbing rubber 17 as a shock absorbing member is fitted in the through hole 16, and when the valve body 9 is closed by the return spring 11,
The lower end portion of the cushion rubber 17 is seated on the valve seat portion 10,
Further, as shown in FIG. 3, when the valve body 9 moves upward, when the valve is opened, the upper end of the cushioning rubber 17 abuts the lower end of the fixed iron core 5, and when the valve is closed. The impact of seating of the valve body 9 and the impact of the valve body 9 that abuts the suction portion 12 of the fixed iron core 5 when the valve is opened can be absorbed by the cushioning rubber 17. When the upper end of the cushioning rubber 17 contacts the lower end of the fixed iron core 5, the inclined surface 13 and the facing surface 15 do not come into contact with each other.

In this embodiment having the above structure, when the valve body 9 is attracted to the fixed iron core 5, the facing surface 15 of the valve body 9 has a taper angle θ of 17.5 degrees. The magnetic gap between the fixed iron core 5 and the valve body 9 is absorbed by the inclined surface 13 of the suction portion 12 that is provided,
The distance is from 3 to the facing surface 15. The inclination angle of the inclined surface 13 with respect to the moving direction of the valve body 8 is the taper angle θ, and the change amount of the magnetic gap when the valve body 8 moves by a predetermined amount corresponds to the moving amount of the valve body. Supposing that L is the change amount of the magnetic gap, S = L × sin θ, and the change amount S of the magnetic gap is smaller than the movement amount L of the valve body 5.

In FIG. 4, the moving amount of the valve body 9 is 1.0 (m) from the closed position, that is, the position where the moving amount is 0 (mm).
It is a figure showing the change of the magnetic gap during the movement to the valve opening position which is m), and the change amount S of the magnetic gap in the duty control valve 1 of the present invention is the change amount of the magnetic gap in the conventional duty control valve. It can be seen that it is smaller than S1.

FIG. 5 is a diagram showing the magnetic attraction force depending on the magnetic gap in the duty control valve 1 of the present invention and the conventional duty control valve. In the conventional duty control valve, the valve body is It can be seen that the magnetic attraction force increases as it approaches the fixed iron core, whereas it gradually increases in the duty control valve 1 of the present invention. Note that FIG. 5 also shows the spring load of the return spring 11 accompanying the movement of the valve body 8. However, the slope of the increase in the magnetic attraction force in the duty control valve 1 of the present invention is the same as the spring load. The result is almost equal to the slope of increase.

Further, as shown in FIG. 6, the valve opening response time during the movement of the valve body in the conventional duty control valve from the valve closing position to the valve opening position is 7.9 (ms), and from the valve opening position. The valve closing response time during moving to the valve closing position is 1
The value was 2.4 (ms), and the valve closing response delay obtained by subtracting the valve closing response time from the valve opening response time was 4.5 (ms). On the other hand, in the duty control valve 1 of the present invention,
The valve opening response time is 9.1 (ms), and the valve closing response time is 1
0.0 (ms) and valve closing response delay is 0.9 (ms)
And it is less than the conventional duty control valve.

Therefore, when the flow rate control valve 1 of the present invention is duty-driven to control the flow rate, like the conventional flow rate control valve whose valve closing response time is longer than the valve opening response time,
The outflow amount does not increase at the time of starting the flow of the fluid, and as shown in FIG. 7, it is possible to obtain output characteristics in which the rise of the outflow amount at the time of starting the flow is smooth.

In this embodiment, the suction portion 12 provided at the lower end of the fixed iron core 5 is formed in a taper shape whose outer diameter is reduced toward the lower end.
2 is provided with an inclined surface 13, while a recess 14 having a mortar shape that fits the suction portion 12 is provided at the upper end of the valve body 9, and an opposing surface 15 parallel to the inclined surface 13 is formed on the inner wall of the recess 14. However, as shown in FIG. 8, a mortar-shaped recess 23 is provided in the suction portion 22 of the fixed iron core 21, an inclined surface 24 is formed on the inner wall of the recess 23, and at the upper end of the valve body 25. It is also possible to provide a suctioned portion 26 having a tapered outer shape whose diameter decreases toward the upper end, and to form a facing surface 27 facing the inclined surface 24 on the side surface of the suctioned portion 26.

[0022]

As described above, in the structure of the present invention, the variation amount S of the magnetic gap = the movement amount L × si of the valve body.
nθ, and the magnetic gap change amount S is the valve body movement amount L
Since the value is smaller, the difference in the magnetic attraction force depending on the magnetic gap at the time of opening or closing the valve is also small, and the valve opening response time from the closed state to the open state and the open state The difference between the valve closing response time and the valve closing response time is reduced. Therefore, when the flow rate control valve of the present invention is duty-driven to control the flow rate, at the time when the flow of the fluid is started, as in the conventional flow rate control valve whose valve closing response time is longer than the valve opening response time. Outflow will not increase.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of an essential part showing a valve closed state of the same embodiment.

FIG. 3 is an enlarged view of an essential part showing a valve open state of the same embodiment.

FIG. 4 is a diagram showing a relationship between a movement amount of a valve element and a magnetic gap in the example and the conventional example.

FIG. 5 is a diagram showing a relationship between a moving amount of a valve element and a magnetic attraction force in the example and the conventional example.

FIG. 6 is a diagram showing a valve closing response time, a valve opening response time, and a valve closing response delay in the example and the conventional example.

FIG. 7 is a diagram showing a relationship between a duty ratio and an outflow amount in the same embodiment.

FIG. 8 is a sectional view showing another embodiment.

FIG. 9 is a sectional view showing a conventional duty control valve.

FIG. 10 is an enlarged view of a main part of the conventional example.

FIG. 11 is a diagram showing a relationship between a duty ratio and an outflow amount in the conventional example.

[Explanation of symbols]

 1 Duty control valve (flow control valve) 2 Bobbin (control valve body) 3 Solenoid 5 Fixed iron core 8 Valve chamber 9 Valve body 10 Valve seat part 11 Return spring 12 Suction part 13 Sloping surface 14 Recessed part (suctioned part) 15 Opposed Surface 17 Buffer rubber (buffer member) 21 Fixed iron core 22 Suction part 24 Sloping surface 25 Valve body 26 Suctioned part 27 Opposing surface

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area F16K 1/36 F16K 1/36 A

Claims (1)

[Claims] 1. A fixed iron core in which a valve element, which is slidably fitted in a valve chamber of a control valve body and is biased to sit on a valve seat provided in the valve chamber, is excited by a solenoid. In a flow control valve that allows fluid to flow while repeating full opening and closing by changing the ratio of ON time and OFF time of a drive signal applied to the solenoid, , A cushioning member penetrating in the moving direction of the valve body is provided, the cushioning member is seated on the valve seat when the valve is closed, and the cushioning member is brought into contact with the suction portion when the valve is opened, while the fixed iron core The flow control valve, wherein an inclined surface that is inclined with respect to the moving direction of the valve body is formed in the suction portion of the valve body, and a facing surface that faces the inclined surface is formed in the suctioned portion of the valve body.