JP2895730B2 - Proportional flow control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve for controlling the flow rate of a fluid in proportion to the output of a drive source, and more particularly to a proportional flow control valve for controlling an intake air amount of an engine. .

[0002]

2. Description of the Related Art In an electronically controlled fuel injection engine,
It is known that a bypass passage is provided in the vicinity of a throttle valve interposed in an intake pipe, and the amount of intake air of the engine is adjusted by opening and closing the bypass passage. For example, a proportional flow control valve is used.

FIG. 5 is a sectional view showing the entire structure of a conventional proportional flow control valve. In the drawing, reference numeral 1 denotes a solenoid, and a fixed iron core 2 is disposed in the center of the solenoid in the longitudinal direction. Further, a movable iron core 3 as a flow rate adjusting means serving as the fixed iron core 2 and a valve body is provided in a space in the guide cylinder 4. An electromagnetic coil 6 wound around a bobbin 5 is provided on the outer periphery of the guide cylinder 4. The outer surface of the electromagnetic coil 6 is covered with a case 8 via an insulating member 7. A lead wire 6a is connected to the upper part of the electromagnetic coil 6 and is led out. Fixed core 2 and movable core 3
A return spring 9 is provided through a spring holder 9a in a predetermined space between the movable iron core 3 and the movable iron core 3 to elastically urge the movable iron core 3 in a direction against the electromagnetic attraction force of the electromagnetic coil 6.

The stepped portion 3 is reduced in diameter near the lower end of the movable iron core 3.
The assist spring 12 is provided between the step 3a and the spring holder 12a attached to the tip of the adjusting screw 11 screwed to the proportional flow control valve body 10. This assist spring 12
Urges the movable core 3 in the direction in which the electromagnetic attraction of the electromagnetic coil 6 acts. Reference numerals 10a and 10b denote a fluid introduction passage and a fluid discharge passage formed in the proportional flow control valve main body 10, and the fluid introduction passage 10a has a bypass passage 13a opening upstream of a throttle valve 14 interposed in the intake pipe 13. The fluid outlet passage 10b communicates with a bypass passage 13b that opens downstream of the throttle valve 14. Further, a plurality of passage holes 4a communicating from the fluid introduction passage 10a to the internal space of the guide cylinder 4 are formed in the side wall of the guide cylinder 4, and the distal end of the guide cylinder 4 has an annular elastic seal member 15 formed therein. And a support member 16 which holds the elastic seal member 15 and is connected to the fluid outlet passage 10b.

[0005] A through hole 3b is provided in the axis of the movable iron core 3 to balance the pressure of the fluid circulating portion with the pressure of the portion formed by the movable iron core 3 and the fixed iron core 2. Further, a support member 16 holding the elastic sealing material 15
Has an inner hole 16a having substantially the same size as the inner diameter of the guide cylinder 4, and the assist spring 12 penetrates.

Next, the operation of the proportional flow valve will be described. FIG. 5 shows a case where the proportional flow control valve is not energized and is in a fully closed state. The fully closed position of the movable core 3 is determined by the balance between the urging forces of the return spring 9 and the assist spring 12, and the adjusting screw 11 is set in advance.
The movable iron core 3 is moved up and down by the
Adjust the position of.

When the electromagnetic coil 6 is energized from the outside through a lead wire 6a to excite the coil 6, the movable core 3 is fixed against the pressing force of the return spring 9 as the energization amount increases. It is sucked to the second side and opens a plurality of passage holes 4 a formed in the side wall of the guide cylinder 4. At this time, the assist spring 12 that urges the movable iron core 3 in the direction in which the suction force works also extends toward the fixed iron core 2 at the same time.

When the movable core 3 is sucked toward the fixed core 2 as described above, the fluid (air) diverted from the intake pipe 13 to the bypass passage 13a opened on the upstream side of the throttle valve 14 is supplied to the fluid introduction passage 10a. , Guide hole 4 of guide tube 4
a, flows between the pitch on the upper end side of the assist spring 12, through the inner hole 16a of the support member 16, and the fluid outlet passage 10b, toward the intake pipe 13 from the bypass passage 13b opened on the downstream side, and the engine (not shown). Supplied to

On the other hand, when the amount of electricity to the electromagnetic coil 6 is reduced, the movable iron core 3 moves in a direction against the electromagnetic force of the electromagnetic coil 6 by the pressing force of the return spring 9, and the passage hole 4 a of the guide cylinder 4 is formed. When the amount of electricity to the electromagnetic coil 6 is reduced to substantially zero, the supply of the fluid (air) to the engine from the bypass passages 13a and 13b is cut off.

In this type of proportional flow control valve, power is supplied to the electromagnetic coil 6 in order to reduce hysteresis due to frictional resistance of the sliding portion and hysteresis of the elastic repulsive force of the return spring 9 and the assist spring 12. By changing the ratio between the ON time and the OFF time by changing the ratio of the ON time and the OFF time, duty control for finely sliding the movable core 3 or changing the constant current value (DC component) to change (AC component) is provided. Dither control for finely sliding the movable core 3 is generally used.

[0011]

The conventional proportional flow control valve is a spool-type valve configured as described above. In order to adjust the flow rate of the fluid with high accuracy, the movable iron core 3 forming the spool must be connected to the proportional iron flow control valve. The radial clearance between the sleeve and the guide tube 4 cannot be so large, and is usually set to 0.02 to 0.2 mm. for that reason,
In the support member 16 holding the elastic seal member 15,
The inner diameter of the inner hole 16a having substantially the same size as the inner diameter of the guide cylinder 4 may be slightly smaller than the outer diameter of the movable iron core 3 due to processing variations or the like. For example, when the energization of the electromagnetic coil 6 suddenly changes from the high duty state to the zero duty state, the movable iron core 3 becomes larger than the steady state due to the sudden and large return elasticity of the return spring 9 and the same movement inertia. The support member 1 moves downward.
6 overshoots to the position of the inner hole 16a, bites into the inner hole 16a and sticks.

When the inner diameter of the inner hole 16a of the support member 16 is larger than the outer diameter of the movable core 3,
Due to the phenomenon described above, the movable iron core 3 is
Overshoot further below the position of the inner hole 16a, the return spring 9 falls off from the spring holder 9a, or excessive stress is applied to the assist spring 12 to cause the assist spring 12 to set, and in the worst case, In the case of (1), there is a problem that the assist spring 12 may be broken.

By the way, the opening area of the plurality of passage holes 4a formed in the side wall portion of the guide cylinder 4 is set in consideration of the pressure loss so that the maximum flow rate of the bypass air required from the engine and the vehicle side can be secured. Have been. Therefore, when the inner diameter of the inner hole 16a of the support member 16 is made sufficiently smaller than the outer diameter of the movable core 3, the problem of the stick of the movable core 3 or the like due to the above-described phenomenon is avoided. The degree of freedom in setting the opening area of the hole is restricted (passage hole 4a).
The maximum opening area of the valve cannot be larger than the opening area of the inner hole 16a), and the components of the proportional flow control valve correspond to the various flow characteristics (for example, the maximum flow rate) of the bypass air required from the engine and the vehicle side. It is difficult to achieve commonality and to respond. For example, for a vehicle type requiring a large amount of bypass air flow, there is a problem in that the entire proportional flow control valve becomes large due to the enlargement of components such as the movable iron core 3 and the guide cylinder 4.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can regulate the fully closed position of the movable iron core with a simple structure without increasing the number of parts and the number of assembling steps. It is an object of the present invention to provide a proportional flow control valve that can share components for different flow characteristics.

[0015]

A proportional flow control valve according to the present invention comprises a guide cylinder having a passage hole communicating from a fluid introduction passage to an internal space, and a fixed iron core provided in the guide cylinder internal space. A movable iron core slidably provided in the guide cylinder inner space portion facing the fixed iron core to open and close the passage hole; and an electromagnetic force provided on the outer periphery of the guide cylinder to drive the movable iron core by energization. An electromagnetic coil that is generated, a return spring that urges the movable core in a direction against the electromagnetic force, an assist spring that urges the movable core in a direction in which the electromagnetic force acts, and fluid leading out of the tip of the guide cylinder A proportional flow control valve comprising: an elastic seal member for connecting to the passage; and a support member holding the elastic seal member and having an inner hole through which the assist spring passes. A stopper for restricting the fully closed position of the movable core by making a hole in the inner hole of the support member, and the opening area of the inner hole is made larger than the fluid passage area of the guide cylinder inner space. It is.

[0016]

According to the present invention, the movable iron core is prevented from moving largely downward even when the power supply to the electromagnetic coil changes from the high duty state to the zero duty state. Also,
The components can be shared for various flow characteristics.

[0017]

【Example】

Embodiment 1 FIG. One embodiment of the present invention will be described with reference to FIGS. In the figure, the same or corresponding parts as those of the conventional configuration (FIG. 5) are denoted by the same reference numerals and description thereof is omitted. In the figure, reference numeral 17 denotes a support member having an oblong inner hole 17a. The oval inner hole 17a has a small diameter dimension A smaller than the outer diameter dimension of the movable core 3 and an opening area of the guide cylinder 4.
It is set to be larger than the fluid passage area of the inner space. That is, the oval inner hole of the support member 17 has a small diameter A portion as a stopper portion 17b for regulating the fully closed position of the movable iron core 3, and has an opening larger than the fluid passage area of the space in the guide cylinder 4. It has a large-diameter dimension B portion for securing an area.

In the first embodiment, the power supply to the electromagnetic coil 6 is temporarily changed from the high duty state to the zero duty state. Due to the large return elasticity and the same movement inertia, even when the movable core 3 moves downward more than in the steady state, the movement of the movable core 3 can be reliably restricted by the stopper portion 17b of the support member 17, and the movable core 3
Can stick to the inner hole 17a of the support member 17 and stick. Further, it is possible to prevent the return spring 9 from dropping off from the spring holder 9a or to apply excessive stress to the assist spring 12.

Further, a large-diameter portion B is provided in the oblong inner hole 17a of the support member 17, and the opening area of the inner hole 17a is made larger than the fluid passage area of the space in the guide cylinder 4 to thereby improve the engine. Also, various flow characteristics (for example, maximum flow rate) of bypass air required from the vehicle side can be dealt with only by changing the number and the shape and size of the passage holes 4a formed in the side wall portion of the guide cylinder 4. This makes it possible to use common components for vehicles that require a large flow rate of bypass air, thereby preventing unnecessary increase in size.

Embodiment 2 FIG. Support member 17 in the first embodiment
Can be shaped as shown in FIGS. 3 and 4. That is, the support member 18 in the present embodiment is
The inner hole 18a having an inner diameter larger than the inner diameter of the movable core 3 is extended inward, and a plurality of projections 18b having an inner diameter smaller than the outer diameter of the movable core 3 are partially provided as stop members. In this case, the opening area of the support member 18 is formed to be larger than the fluid passage area of the space in the guide cylinder 4.

Note that the support members 17 and
The inner holes 17a and 18a having a complicated shape can be easily formed by forming the resin material 18 by resin molding or aluminum forging. Further, the shape of the inner holes of the support members 17 and 18 is not limited to each of the above embodiments, but may be any shape that can appropriately achieve the effects of the present invention.

[0022]

As described above, according to the present invention, the stopper is provided in the inner hole of the support member to restrict the fully closed position of the movable iron core, and the opening area of the inner hole is reduced by the guide cylinder. The fluid passage area of the inner space is larger than the area.Therefore, it is possible to regulate the fully closed position of the movable iron core with a simple structure without increasing the number of parts and assembly man-hours, and obtain a highly reliable proportional flow control valve at low cost. Has the effect. In addition, the components can be shared for various different flow characteristics, and there is an effect that unnecessary enlargement can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an overall configuration of a proportional flow control valve according to Embodiment 1 of the present invention.

FIG. 2 is a plan view illustrating a shape of a support member according to the first embodiment.

FIG. 3 is a plan view showing a different shape of a support member according to the second embodiment.

FIG. 4 is a cross-sectional view illustrating a shape of a support member according to a third embodiment.

FIG. 5 is a cross-sectional view showing the overall configuration of a conventional proportional flow control valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solenoid 2 Fixed iron core 3 Movable iron core 3a Step part 4 Guide cylinder 4a Passage hole 5 Bobbin 6 Electromagnetic coil 6a Lead wire 7 Insulating member 8 Case 9 Return spring 9a, 12a Spring holder 10 Proportional flow control valve body 10a Fluid introduction passage 10b Fluid Outlet passage 11 Adjustment screw 12 Assist spring 13 Intake pipe 13a, 13b Bypass passage 14 Throttle valve 15 Elastic seal member 16, 17, 18 Support member 16a, 17a, 18a Inner hole 17b Stopper portion 18b Projection

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-46072 (JP, A) JP-A-4-46282 (JP, A) JP-A-3-6173 (JP, U) JP-A-3-4673 12676 (JP, U) JP-A-63-145078 (JP, U) JP 3-537 (JP, Y2) (58) Field surveyed (Int. Cl. ⁶ , DB name) F16K 31/00-31 / 11 F02M 23/04

Claims (3)

(57) [Claims] 1. A guide cylinder having a passage hole communicating from a fluid introduction passage to an internal space, a fixed core provided in the guide cylinder internal space, and a guide core internal space facing the fixed core. A movable core that is slidably provided on the guide tube and opens and closes the passage hole; an electromagnetic coil that is provided on the outer periphery of the guide cylinder and generates an electromagnetic force that drives the movable core by energization; A return spring for urging the movable iron core, an assist spring for urging the movable iron core in a direction in which an electromagnetic force acts, an annular elastic seal member for connecting a tip of the guide cylinder to a fluid outlet passage, A proportional flow control valve comprising: a support member holding an elastic seal member and having an inner hole through which the assist spring passes. Proportional flow control valve, wherein a stopper portion for regulating the fully closed position of the heart is provided, and an opening area of the inner hole and the above fluid passage area of the guide cylinder space. 2. The proportional flow control valve according to claim 1, wherein an inner hole of the support member is formed in an oblong shape. 3. The support member according to claim 1, wherein a plurality of projections extending inward are provided in the inner hole of the support member.
Proportional flow control valve as described.