JPH0450569A - Proportional flow control valve - Google Patents

Abstract

PURPOSE:To obtain a proportional flow control of stable characteristic, and of good controllability by extending the valve in the direction of a sliding axis, up to the same position as where a spring is abutted on a holder, at the shortest, beyond the abutted position with the holder. CONSTITUTION:When an electromagnetic coil 6 is electrified, a moving iron core 4 is attracted to the side of a fixed iron core 2 against the pressing power of a return spring 5, and a valve assembly body 18 is moved, and a valve is opened thereby. The resilience force generated by the separation following the very small vibration of the valve assembly body 18 caused by the control, or by the collision at the time of being seated, is absorbed by a spring 15 for energizing a valve 14. Since the end of the valve is protruded and thus formed in such a way that the outer periphery of a holder 16 is surrounded by the end, which is set beyond the position where a spring 8 is abutted on the holder 16, even when the valve 14 is separated from a seat, and is stroked by a preset amount of time, the stream of a fluid will not be disturbed or channeled by the holder 16.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a valve that controls the flow rate of fluid proportionally to the output of a driving source, and is particularly applied to a valve near a throttle valve in an intake pipe of an internal combustion engine. It is useful as a proportional steam control valve for adjusting the amount of intake air, which is placed in a bypass passage provided in a.

[Prior Art] Electronically controlled fuel injection engines have been known in the art in which a bypass passage is provided near the throttle valve in the intake pipe, and the intake air amount of the engine is adjusted by opening and closing this bypass passage. be.

FIG. 4 shows an example of a proportional flow control valve used to open and close the bypass passage, in which 1 is a solenoid device, and a fixed iron core 2 is disposed in the center of the solenoid device in the longitudinal direction. . A cylindrical case 3 is attached to the inner periphery of the solenoid device 1, and a movable core 4 serving as a flow rate adjusting means serving as a valve body is disposed at a position facing the fixed core 2, and a return spring 5 is interposed.

An electromagnetic coil 6 is disposed on the inner circumferential surface of the case 3 via an insulating material 3a, and a pipe 7 is attached to the inner circumferential surface of the bobbin 6a around which the electromagnetic coil 6 is wound.
The fixed iron core 2 and the movable iron core 4 are arranged inside. The return spring 5 is provided in the space between the fixed core 2 and the movable core 4 via a spring holder 5a, and the movable core 4 is moved in a direction that resists the electromagnetic attraction force of the electromagnetic coil 6 by the return spring 5. is energized by That is, due to the return spring 5, a force that presses the movable core 4 in the left direction in FIG. 4 is constantly acting on the movable core 4. A lead wire 6b led out to the outside is connected to the electromagnetic coil 6.

Further, a spring 8 is disposed on the opposite side of the movable core 4 from the return spring 5.

This spring 8 includes a stepped portion 4a whose diameter is reduced near the tip (left end in FIG. 4) of the movable core 4, and a spring holder 9.
The spring holder 9 is fixed to the tip of the adjusting screw lO.

The tip of the movable core 4 including the step portion 4a, the spring 8
．． The spring holder 9 and the adjusting screw 10 are located in a cavity 11b inside the proportional flow control valve body 11 connected to the solenoid device l. The proportional flow rate control valve body 11 is provided with a fluid introduction passage 11a near the end on the side of the solenoid device l, and a fluid outlet passage 11c that opens into the cavity 11b near the tip (the left end in FIG. 4). It is provided. The tip of the pipe 7 (the left end in FIG. 4) is held by a support member 13° fixed within the proportional milk control valve main body 11 via the buffer material 12, and thereby the proportional flow control valve main body The eleven empty chambers 11b are divided from the fluid introduction passage 11a side.

The adjustment screw lO is screwed into the proportional flow rate control valve body 11 in a direction from the distal end side where the fluid outlet passage 11c is provided toward the movable iron core 4 side. The movable core 4 is always urged to the right in FIG. 4, that is, in the direction in which the electromagnetic attractive force acts, by the spring 8 held by the spring holder 9 fixed to the adjustment screw 10.

A fluid communication hole 7a of a predetermined size is formed near the tip of the vibrator 7 and communicates with the fluid introduction passage ILa of the proportional flow control valve body 11.

This fluid communication hole 7a is provided at a position where it is closed by the outer peripheral surface of the movable iron core 4 when the electromagnetic coil 6 is not energized.

Further, in the axial core portion of the movable core 4, there is provided a structure for balancing the pressure on the side of the cavity 11b communicating with the fluid outlet passage 11c and the pressure in the space formed between the movable core 4 and the fixed core 2. A conduction hole 4b is provided.

The spring 8, which is attached between the spring holder 9 and the stepped portion 4a of the movable core 4 and biases the movable core 4 in the direction of the attraction force exerted by the electromagnetic coil 6, has its biasing force adjusted in advance by an adjustment screw 10. , whereby the position of the movable iron core 4 is set.

In the proportional flow rate control valve having such a configuration, when the electromagnetic coil 6 is energized and excited, the movable iron core 4 is attracted toward the fixed iron core 2 against the pressing force of the return spring 5. At this time, the spring 8 acting in the suction direction expands as the movable iron core 4 moves.

Then, when the movable iron core 4 is attracted to the fixed iron core 2 side as described above, the fluid circulation hole 71 of the vibrator 7 is opened, and the fluid (air) diverted from the intake pipe to the bypass passage is transferred to the fluid introduction passage 11a. 7, the pitch of the spring 8, and the fluid outlet passage 11c via the cavity 11b.
It flows through the bypass passage and joins the flow in the intake pipe.

In addition, in this type of proportional flow control valve, in order to reduce hysteresis due to frictional resistance of the sliding part, the energization of the electromagnetic coil is interrupted at a certain frequency, and the ratio of the ON time and OFF time is changed. Generally, duty control is used to cause the movable iron core to slide slightly, or dither control is used to cause the movable iron core to slide slightly by varying a constant current value (DC portion) (AC portion). ing.

By the way, since the proportional flow rate control valve shown in FIG. 4 is a spool type valve, fluid may leak from the clearance between the movable core 4 forming the spool and the vibe 7 forming the sleeve. As shown in Figure 5, even when the control duty was reduced to zero, the flow rate did not become zero. However, in controlling the bypass air flow rate of an internal combustion engine, when there is no need to flow bypass air during idling operation, it is desirable to reduce the amount of leakage from the bypass passage to zero and lower the engine speed to save fuel.

In particular, in small-displacement vehicles, the absolute value of the air flow rate required for idling itself is small, so the engine may be able to maintain idling rotation with just the amount of leakage from the throttle valve. In order to improve the fuel consumption rate by reducing the amount of leakage from the bypass passage as mentioned above to zero and preventing the engine's idle speed from increasing unnecessarily, the relationship between the car grade and the fuel consumption rate can be improved. This is something that is strongly desired.

Conventionally, spool-type valves have been known in which a stopper is provided so as to come into contact with the tip of the control spool (movable iron core) when the electromagnetic coil is not energized (see Japanese Utility Model Application No. 63-145078). ), such a stopper may also function as a valve seat in a proportional flow rate control valve having a structure as shown in FIG. 4, thereby improving sealing performance. However, in this type of proportional flow control valve, as mentioned above,
In order to reduce hysteresis caused by frictional resistance in sliding parts, duty control or dither control is generally used to cut and hold current to the electromagnetic coil at a certain frequency. The flow rate adjustment means constituted by the above collides with the valve seat each time the seat is taken off and seated repeatedly, thereby producing a tapping sound, which in turn causes an abnormal phenomenon in the flow rate characteristics as shown in FIG. 6. Additionally, in order to avoid such tapping sounds and abnormal phenomena, it is possible to provide an elastic body such as rubber on the contact surface of the flow rate adjusting means or the valve seat.
In that case, in order to fully achieve the intended purpose, the hardness of the elastic body must be considerably reduced to make it easy to conform to, and in this case, the contact position and contact load between the flow rate adjustment means and the valve seat must be adjusted. As a result, a problem arises in that the valve opening timing varies greatly.

The above circumstances are the same in the case of poppet valves. In the case of a poppet valve, it is easy to improve sealing performance due to its structure, but on the other hand, the above-mentioned tapping noise and abnormal phenomena in flow characteristics are likely to occur.

In order to solve this problem, Japanese Patent Application Laid-Open No. 63-2435
As described in Publication No. 82, a valve body made of a hard resin material with a bellows integrally formed on the side is loosely fitted into a moving core held by a leaf spring, and a locking piece is inserted into the moving core held by a leaf spring. to restrict the displacement of the valve body toward the valve seat side, and furthermore, an elastic body is arranged between the valve body and the movable iron core,
A poppet valve has been proposed in which the elastic body presses the valve body toward one side with a predetermined biasing force.

[Problems to be Solved by the Invention] When a conventional spool-type valve is used to configure a proportional flow control valve that opens and closes a passage that bypasses a throttle valve of an internal combustion engine, as described above, the movable spool-type valve There is leakage from the clearance between the iron core and the sleeve (cylindrical member), which causes the problem that the flow rate cannot be completely reduced to zero even in an operating range where it is desired to reduce the flow rate to zero. In addition, if a valve seat is provided, when duty control or dither control is performed, a tapping sound may be generated when the flow rate adjustment means leaves or seats on the valve seat, or an abnormal phenomenon may occur. If an elastic body is provided in the seating portion in order to avoid such abnormal phenomena, a problem arises in that the valve opening timing increases due to variations in the abutting position and the abutting load.

In a poppet type valve, as described above, a valve body made of a hard resin material integrated with a bellows is loosely fitted into a movable core held by a plate spring, and this valve body is locked and pressed to one side by an elastic body. There are examples of attempts to solve the above problems by doing so. But in this example,
It is necessary to combine two or more types of coil springs, one leaf spring, one bellows, etc., and determine the operating characteristics based on the balance between this and the attraction force of the electromagnetic coil, so setting the characteristics is complicated and tends to vary. The problem is that adjustment is difficult. In addition, in the above example, if the pressures are not balanced by conducting each space between the valve body and the holding plate, between the holding plate and the magnet plate, and between the movable iron core and the fixed iron core (stator core), a damper effect will occur. As a result, fast operation cannot be achieved. Therefore, a plurality of conduction spaces are required, and there is a greater possibility that the conduction spaces will be clogged due to intrusion of foreign matter, and if the conduction spaces are clogged, normal flow characteristics will not be obtained.

In addition, even if a valve assembly is configured to solve these problems, when the valve (valve body) is unseated and stroked by a predetermined amount, the minimum flow path area between the valve and the valve seat is At the same time, the valve assembly must be configured to ensure a predetermined contact area with the valve seat while allowing the sliding part to fall due to clearance. Therefore, if there is not much room between the valve seat and the holder (locking piece), the annular gap between the valve seat and the holder will fluctuate unevenly, and as a result, the flow rate characteristics will change as shown in Figure 7. This causes undulations. In addition, when trying to increase the maximum flow rate of such a valve assembly and increasing the stroke of the valve assembly, if there is not enough space between the valve seat and the holder as described above, the valve assembly Even if the three-dimensional stroke is increased, the problem arises that choke occurs in the gap between the valve seat and the holder, limiting the flow rate.On the other hand, increasing the inner diameter of the valve seat prevents the above-mentioned choke from occurring. Therefore, when trying to increase the diameter of the contact circle between the valve and the valve seat, it is necessary to increase the diameter of the sliding support part of the movable iron core so that the pressure applied to the valve assembly does not become unbalanced. Therefore, the problem arises that the entire proportional flow control valve becomes larger.Furthermore, if the diameter of the contact circle between the valves is increased as described above, the flow rate gain for the valve assembly becomes large.
Problems such as deterioration of controllability also occur.

This invention has been made to solve these problems, and the problem is that when the flow rate adjusting means is unseated and seated on the valve seat, a tapping sound is generated or an abnormal phenomenon in the flow rate characteristics occurs. In addition, it is possible to prevent waviness in the flow characteristics due to collapse due to the clearance of the sliding part, and it is possible to support large flow specifications without increasing the size or deteriorating controllability. The purpose of the present invention is to provide a proportional flow control valve with fully closed function.

[Means for Solving the Problems] A proportional flow control valve according to the present invention includes a valve seat provided in a proportional flow control valve body, a valve slidably inserted into a movable core, and a valve seat between the movable core and the proportional flow control valve. A holder is fixed to the movable iron core, and a holder is fixed to the movable iron core, and the elastic body provided in the holder biases the valve in the direction toward the valve seat, and the elastic body restricts the movement of the valve in the direction toward the valve seat. A spring is provided, one end of which is held on the proportional flow control valve main body side, and which biases the movable core in a direction against the biasing force of the return spring through the holder, and is composed of the movable core, the valve, the elastic body, and the holder. The valve assembly is biased by the return spring and slidably supported by the cylindrical member, and the end of the valve near the spring is moved beyond the contact area with the holder to at least contact the spring with the holder. It extends in the sliding axis direction to the same position as the section.

[Function] In this invention, the valve assembly consisting of the movable core, the valve, the elastic body, and the holder is pressed against the valve seat by the return spring while the elastic body tensions the movable core and the valve with a predetermined biasing force. It is brought into contact with a predetermined urging force. Therefore, the elastic body absorbs the repulsive force generated by the collision with the valve seat when the valve assembly is unseated or seated due to minute vibrations of the valve assembly during flow rate control by duty control or dither control. Therefore,
This prevents hammering noise and abnormal flow characteristics caused by collision between the valve and the valve seat.

In addition, the end of the valve on the side closer to the spring should extend in the sliding axis direction beyond the contact area with the holder, to the same position as the contact area between the spring and the holder. This prevents the fluid flow from being obstructed or deflected by the holder even when the valve is unseated and stroked by a predetermined amount.This prevents fluctuations in the flow characteristics and also increases the maximum flow rate. Even if the stroke is increased, no choke will occur in the gap with the holder.

[Embodiment] Fig. 1 is a longitudinal sectional view of one embodiment of the proportional flow control valve according to the present invention, and Fig. 2 is an enlarged view of the main parts thereof. here,
The same or corresponding parts as in the conventional example shown in FIG. 4 are given the same reference numerals.

1 is a solenoid device, and a fixed iron core 2 is disposed in the center of the solenoid device in the longitudinal direction. Further, a cylindrical case 3 is attached to the inner circumference of the solenoid device 1, and the fixed iron core 2
A movable iron core 4 is disposed at a position facing the , and a return spring 5 is interposed therebetween.

The movable iron core 4 has a reduced diameter portion 4c, and a valve 14 is slidably fitted into the reduced diameter portion 4c. A spring 15 is provided on the outer periphery of the reduced diameter portion 4c to bias the valve 14 toward the distal end, and a holder is provided at the distal end of the reduced diameter portion 4c to restrict movement of the valve toward the distal end. 1
6 is fixed. The spring 15 is connected to the valve 14
The valve 14 is brought into contact with the holder 16 by mutually tensioning the movable iron core 4 and the movable iron core 4. In this way, the movable iron core 4, the valve 14, the spring 15, and the holder 16 constitute a valve assembly 18.

Further, a spring 8 is disposed on the opposite side of the movable core 4 from the return spring 5.

The spring 8 is attached between the holder 16 fixed to the tip of the reduced diameter portion 4c of the movable iron core 4 and a spring holder 9. It is fixed to the tip of screw lO.

The valve 14 has a spring 8 that comes into contact with the holder 16.
The end closer to the valve seat 13 is extended so as to surround the outer periphery of the holder 16 and protrude in the sliding axis direction beyond the position of contact with the holder 16. The contact surface is a spherical contact surface that comes into contact with the tapered (conical) sheet surface.

The inner peripheral tip position of the spherical abutment surface indicated by line 2 in FIG. 2 is set beyond the abutment position between the spring 8 and the holder 16, which is indicated by line 2 in the same figure. In addition,
Line 2 in FIG. 2 indicates the position of the contact portion between the valve 14 and the valve seat 13. Here, the diameter of the contact portion between the tapered sheet surface and the spherical contact surface is, for example, 11 mm, and is set to approximately match the sliding diameter of the movable iron core 4 and the vibrator 7. . The above valve seat 13 and valve 1
4 is, for example, polybutylene terephthalate (PBT)
It is possible to configure

An electromagnetic coil 6 is disposed on the inner peripheral surface of the case 3 via an insulating material 3a, and a vibrator 7 is attached to the inner peripheral surface of the bobbin 6a around which the electromagnetic coil 6 is wound.
The fixed iron core 2 and the movable iron core 4 are disposed facing each other inside the . The return spring 5 is provided in the space between the fixed core 2 and the movable core 4 via a spring holder 5a, and the movable core 4 is moved in a direction that resists the electromagnetic attraction force of the electromagnetic coil 6 by the return spring 5. is energized by That is, due to the return spring 5, a force that presses the movable core 4 in the left direction in FIG. 1 is constantly acting on the movable core 4. A lead wire 6b led out to the outside is connected to the electromagnetic coil 6.

The proportional flow control valve body 11 is provided with a fluid introduction passage 11a near the end on the solenoid device 1 side, and a fluid outlet passage 11c on the tip (left end in FIG. 1) side.

The solenoid device l and the proportional flow control valve body 11 are:
By fitting the proportional flow control valve main body 11 into the rib-shaped guide portion 19a of the guide member 19 fitted to the end of the solenoid device 1, looseness (mutual fitting and fixation) is eliminated. The guide member 19 holds one end of the vibrator 7 that slidably supports the movable core 4.The proportional A quantity control valve body 11 has a valve located opposite the valve assembly 18. The sheet 13 is fitted, thereby defining a cavity 11b communicating with the fluid outlet passage 11c from the fluid introduction passage 1.1a side.

The adjusting screw 10 is screwed together from the distal end side of the proportional flow rate control valve main body 11 where the fluid outlet passage 1.1c is provided toward the movable iron core 4 side. The spring 8 held by the spring holder 9 fixed to the adjustment screw 10 always urges the movable core 4 in the same direction as the direction in which the electromagnetic attractive force acts.

The valve assembly 18 assembled as described above receives the biasing force of the spring 8 and the return spring 5, and the movable core 4 is allowed to fall against the valve seat 13 due to the clearance with the vibrator 7. be brought into contact with Here, the biasing force of the spring 8 attached between the holder 16 and the spring holder 9 is adjusted in advance by the adjustment screw 10, so that the biasing force of the valve assembly 18 toward the valve seat 13 is increased. be adjusted. In addition, at this time, the valve 14 and the valve seat 13
The contact load between the valve 14 and the holder due to the spring 15! The setting is such that the load is smaller than the contact load with the valve 14 and the holder 16, and there is no gap between the valve 14 and the holder 16 when the valve is fully closed.

Further, a fluid lead-out passage 11 is provided in the axial center portion of the movable iron core 4.
A through hole 4b is provided in order to balance the pressure on the side of the cavity 11b communicating with the movable iron core 4 and the pressure in the space formed between the movable iron core 4 and the fixed iron core 2. This conduction hole 4
b has a maximum diameter of 3 mm or more.

In the proportional flow rate control valve having such a configuration, when the electromagnetic coil 6 is energized, the movable core 4 is attracted toward the fixed core 2 against the pressing force of the return spring 5, and the valve assembly 18 moves to open the valve. do.

Here, when using this proportional flow rate control valve to control the flow rate by duty control or dither control, the repulsive force generated by the collision when unseated or seated due to minute vibrations of the valve assembly 18 caused by these controls is , valve 1
4 is absorbed by the spring 15 which biases it.

Further, as described above, the end of the valve 14 is formed to protrude so as to surround the outer periphery of the holder 16, and its tip is connected to the spring 8.
Since the valve 14 is set beyond the abutment position of the holder 16, even if the valve 14 is unseated and stroked by a predetermined amount, the fluid flow will not be obstructed or biased by the holder 16. There's nothing to do. the result,
As shown in FIG. 3, the sealing performance is ensured when the duty is zero, and stable flow characteristics are obtained without abnormal phenomena and without fluctuations in the flow characteristics due to the collapse of the valve assembly.

In this embodiment, as described above, the solenoid device 1 and the proportional flow control valve body 11 are fitted together without play by the guide member 19, so that the abutting portion between the valve assembly 18 and the valve seat 13 is not misaligned. is the movable iron core 4 and pipe 7
The valve assembly 18 only falls down due to the clearance between the valve seat 3 and the valve seat 3.
Since the contact surface is spherical, even if the above-mentioned collapse occurs, the sealing performance is ensured by contacting the contact portion with a predetermined diameter. The sliding clearance between the movable iron core 4 and the vibrator 7 is 0.02 to 0.2 nm, and the ratio L/D between the sliding length L and the sliding diameter is 1.5 or more.

Further, in this embodiment, the valve seat 13 is
Since the diameter of the contact circle between the valve 14 and the valve 14 is approximately the same as the sliding diameter between the movable iron core 4 and the pipe 7, even if negative pressure in the intake pipe is applied to the fluid outlet passage 11C when no current is applied, the conduction hole 4
The forces applied to the valve assembly 18 from the left and right sides via b are balanced and a stable state is maintained.

In the above embodiment, the tip position of the valve 14 is set beyond the contact point between the spring 8 and the holder 16; Effects of the Invention As described above, according to the present invention, a valve assembly is constituted by a movable core, a valve, an elastic body, and a holder, and this is connected by a return spring. Biasing: The valve is slidably supported by a cylindrical member, and the end of the valve is extended in the sliding axis direction beyond the contact part with the holder to at least the same position as the contact part between the spring and the holder. As a result, even when controlling the flow rate by duty control or dither control,
In addition to ensuring the full opening function, it is possible to absorb the repulsive force caused by collisions with the valve seat when leaving or seating the valve seat, eliminating hitting noise and abnormal phenomena in flow characteristics.
It has the characteristics of being able to eliminate flow rate fluctuations due to the collapse of the valve assembly, and increasing the maximum flow rate without increasing the size of the entire proportional flow 1 control valve or increasing the flow rate gain with respect to the valve stroke. It is possible to provide a proportional flow control valve with a fully closed function that is stable and has good controllability.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of an embodiment of the proportional flow control valve according to the present invention, Fig. 2 is an enlarged view of its main parts, Fig. 3 is its flow characteristic diagram, and Fig. 4 is a conventional spool type proportional flow rate. A vertical cross-sectional view of the control valve, Fig. 5 is its flow rate characteristic diagram, Fig. 6 is a typical flow rate characteristic diagram of a conventional poppet type valve, and Fig. 7 is a flow rate characteristic diagram explaining flow rate fluctuations due to collapse of the valve assembly. It is. In the figure, ■ is a solenoid device, 2 is a fixed core, 3 is a case, 4 is a movable core, 4c is a reduced diameter part, 5 is a return spring, 6 is an electromagnetic coil, 7 is a vibrator (cylindrical member),
8 is the spring, 1 is the proportional flow control valve body, ll
a is a fluid introduction passage, lie is a fluid outlet passage, 13 is a valve seat, 14 is a valve, 15 is a spring (elastic body)
, 16 is a holder, 18 is a valve assembly, and 19 is a guide member. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] (1) An electromagnetic coil wound so as to form a magnetic field by applying a current, a case made of a magnetic material into which the electromagnetic coil is inserted, a fixed iron core that forms a magnetic circuit together with the case, and the electromagnetic coil. a movable core slidably disposed within a cylindrical member so as to be attracted in a direction toward the fixed core by an electromagnetic attraction force; and a return force that urges the movable core in a direction opposite to the electromagnetic attraction force. In a proportional flow control valve that includes a spring and controls the flow rate of fluid that enters from a fluid introduction passage of a proportional flow control valve body and flows to a fluid outlet passage by sliding of the movable iron core, a valve seat is provided in the proportional flow control valve body. a valve is slidably inserted into the movable iron core, the valve is biased in a direction toward the valve seat by an elastic body provided between the movable iron core, and the valve is pushed by the elastic body. A holder that restricts movement in the direction toward the valve seat is fixed to the movable iron core, and one end of the holder is held on the opposite side of the valve to the proportional flow control valve main body side, and the return spring is connected through the holder. A spring that biases the movable core in a direction against the biasing force is provided, and the movable core, the valve, the elastic body, and the holder are biased by the return spring and slidably supported by the cylindrical member. The end of the valve closer to the spring is slid over the contact portion with the holder to at least the same position as the contact portion between the spring and the holder. A proportional flow control valve characterized by extending in the direction of the dynamic axis.