JPH0450567A - Proportional flow control valve - Google Patents

Abstract

PURPOSE:To obtain a proportional flow control with a fully closed function of high reliability by energizing the valve through a return spring, so as to be slid and supported by a cylindrical member, and by folding and whereby overlapping the end of the valve and the end of the cylindrical member with each other, in the direction of a sliding axis. 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. When a flow is controlled by duty control or by dither control, 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. As a result, a sealing characteristic at the time when a duty is zero, is ensured, and a flow characteristic without striking noise or abnormal phenomenon, can be obtained. Since the end part of the valve 14 is overlapped in the direction of a sliding axis in such a way that the end part of a pipe 7 is covered from the outside, it is prevented that a blow-by gas or a spitting gas from an engine is directly flown into the valve 14 and the sliding part of the moving iron core 4.

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 flow rate control valve for adjusting the amount of intake air disposed 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 in the vicinity of the throttle valve in the intake pipe, and the intake air amount of the ennon 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, where ■ is a solenoid device, in which a fixed iron core 2 is disposed in the longitudinal direction in the center of the solenoid device. . Further, a cylindrical case 3 is attached to the inner periphery of the solenoid device j, and at a position facing the fixed iron core 2, a flow rate adjusting means serving as a valve body and 1. A movable iron core 4 is provided, and a return spring 5 is interposed therebetween.

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 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 10.

The tip of the movable core 4 including the step portion 4a, the spring 8
The spring holder 9 and the adjustment screw 10 are connected to a cavity 11. in the proportional flow control valve body 11 connected to the solenoid device 1. It is located at b. The proportional flow rate control valve body 11 is provided with a fluid introduction passage 11a near the end on the side of the tunoid device 1, and a fluid outlet passage opening into the cavity 11b near the tip (the left end in FIG. 4). 11
c is provided. The tip of the vibrator 7 (the left end in FIG. 4) is held by a support member 13° fixed within the proportional flow control valve body 11 via a cushioning material 12,
As a result, the above-mentioned empty space 1 of the proportional flow control valve body 11
1b is separated 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 11a 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 center portion of the movable iron core 4, there is a U.
A conduction hole 4b is provided for the purpose of this.

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 sucked toward the fixed iron core 2 side as described above, the fluid circulation hole 7a 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, The fluid outlet passage 1.1 passes through the fluid circulation hole 7a of the vibrator 7, the pitch of the spring 8, and the cavity 1.1b.
lc, 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 leaks from the clearance between the movable core 4 forming the spool and the pipe 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 to zero17 and preventing the engine's idle speed from increasing unnecessarily, it is necessary to improve the fuel consumption rate by reducing the amount of leakage from the bypass passage as described above. This is something that is strongly desired from a relationship standpoint.

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 also functions as a valve seat () in a proportional flow rate control valve having the structure shown in FIG. 4, and it is thought that this improves the sealing performance. but,
In this type of proportional flow control valve, as mentioned above, duty control and dither control are used in which the energization of the electromagnetic coil is interrupted at a certain frequency in order to reduce hysteresis due to frictional resistance of the sliding part. If a valve seat is provided, as is generally done, the flow rate adjusting means constituted by a movable iron core will collide with the valve seat every time the seat is unseated and seated, causing a banging sound. This causes an abnormal phenomenon in the flow characteristics as shown in . Additionally, in order to avoid such tapping sounds and abnormal phenomena, it is possible to install an elastic body such as rubber on the flow rate adjustment means or the contact surface of the valve seat, but in that case, it is possible to sufficiently achieve the intended purpose. In order to do this, the hardness of the elastic body must be considerably reduced so that it conforms easily, and this will cause variations in the contact position and contact load between the flow rate adjustment means and the valve seat, and as a result,
A problem arises in that the variation in valve opening timing increases.

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 or abnormal phenomenon may occur when the flow rate adjustment means leaves and seats the valve seat. If an elastic body is provided in the seating portion in order to avoid noise and abnormal phenomena, a problem arises in that the valve opening timing increases due to variations in the contact position and contact load.

In a poppet type valve, as mentioned 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 screw, and this valve body is pushed to one side by an elastic body. There are examples of attempts to solve the above problems by configuring the system as follows. However, in this example, it is necessary to combine two or more types of coil springs, leaf springs, bellows, etc., and determine the operating characteristics by the balance between this and the attraction force generated by the electromagnetic coil, so setting the characteristics is complicated. There is also the problem that variations tend to occur and 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. This will prevent fast operation. Therefore,
A plurality of conductive spaces are required, which increases the possibility that the conductive spaces will be clogged due to intrusion of foreign matter, and if the conductive spaces are clogged, normal flow characteristics will not be obtained.

Furthermore, even if these inconveniences are solved, when controlling the bypass air flow rate of an internal combustion engine, deposits such as carbon and oil due to the inflow of blow-by gas from the upstream side of the intake passage and the blowback of the engine from the downstream side will cause the proportional flow rate control. If it is not possible to prevent deposits from adhering to the sliding parts of the valve and the movable iron core, the adhesion of these deposits will deteriorate the sliding properties and cause problems such as those mentioned above.

That is, if the valve and the movable iron core are kept in a tensioned state and cannot slide, the collision repulsion force between the valve and the valve seat cannot be absorbed, resulting in hammering noise and abnormal flow characteristics. In addition, if the elastic body is compressed to a certain extent and cannot slide, the valve will remain open even if the drive source is turned off, and in the worst case, it will cause the engine to overspeed and run out of control. There is a risk that this may lead to

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. Moreover, when used to control the bypass air flow rate of an internal combustion engine, it can prevent deposits caused by blow-by gas inflow or engine blowback from adhering to the collision repulsion absorption structure and causing malfunction. The purpose is to provide a highly reliable proportional flow control valve with a fully closed function.

[Means for solving the problem] The proportional flow control valve according to the present invention has a proportional flow rate of 11fI.
l A valve seat is provided in the control valve body, the valve is slidably inserted into the movable core, the valve is biased toward the valve seat by an elastic body provided between the movable core, and the elastic body A holder that restricts the movement of the valve in the direction toward the valve seat is fixed to the movable iron core.
The 7 valve assembly consisting of the movable iron core, valve, elastic body and holder is biased by a return spring and the cylindrical member is activated to 11! The end of the cylindrical member and the end of the cylindrical member opposite thereto are overlapped with each other in the direction of the sliding axis.

[Function] In this invention, the valve assembly consisting of the movable core, the sleeve 1 elastic body and the holder is rotated by the return spring in a state where the elastic body tensions the movable core and the valve with a predetermined biasing force. It is brought into contact with the valve seat with a predetermined biasing force.Therefore, 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, the repulsive force generated by collision with the valve seat is suppressed. The elastic body absorbs it. Therefore, it is possible to prevent the occurrence of hammering noise due to the collision between the valve and the valve seat, and to prevent abnormal phenomena in the flow characteristics. Also, the end of the valve and the cylinder facing it can be prevented from occurring. By the ends of the members overlapping each other in the direction of the sliding axis,
Blow-by gas and gas blown back from the engine are prevented from flowing directly into the sliding parts of the valve and movable iron core, and as a result, deposits such as carbon and oil contained in those gases enter and adhere to the sliding parts. is prevented.

[Embodiment] FIG. 1 is a longitudinal sectional view of an 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.

Reference numeral 1 denotes 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 spring 15 is provided at the distal end of the reduced diameter portion 4c to restrict movement of the valve 14 toward the distal end. A holder 16 is fixed. The spring 15 tensions the valve 14 and the movable core 4 against each other and brings the valve 14 into contact with the holder 16. In this way, the movable core 4, the valve 14, the spring 15, and the holder 16 are assembled into a valve assembly. A solid body 18 is constructed. Here, the end of the valve 14 on the side of the vibrator 7 is enlarged in diameter to form an annular shape, and the end of the valve 14 and the vibrator 7 The ends of the sliders overlap each other in the direction of the sliding axis. The amount of overlap between the end of the valve 14 and the end of the vibrator 7 in the sliding axis direction becomes a predetermined minimum value (in terms of dimensions) when the valve 14 is seated on the valve seat 13. As 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.
The dimensions are set so that the valve assembly 18 does not come into contact with the guide member 19 even when the valve assembly 18 moves and becomes fully open.

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.

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 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.

What is the solenoid device l and the proportional flow control valve body l?
The proportional flow control valve main body 11 is fitted into the rib-shaped guide portion 19& of the guide member 19 fitted to the end of the solenoid device 1, so that they are fitted and fixed to each other without play. Further, this guide member 19 holds one end of the vibrator 7 that slidably supports the movable iron core 4. A valve seat 13 is fitted into the proportional flow rate control valve body 11 at a position facing the valve assembly 18, whereby a cavity 11b communicating with the fluid outlet passage 11c is separated from the fluid introduction passage 11a side. has been done.

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 lie is provided toward the movable iron core 4 side. And this adjustment screw l
The spring 8 held by the spring holder 9 fixed at O always biases 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 lO, so that the biasing force of the valve assembly 18 toward the valve seat 13 side is adjusted in advance. 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 16 due to the spring 15 is smaller than the contact load between the valve 14 and the holder 16, and settings are made such that no gap is created between the valve 14 and the holder 16 when fully opened.

Further, the seat surface of the valve seat 13 is tapered (conical), and the contact surface of the valve 14 with respect to the seat surface is spherical. Here, the diameter of the contact portion between the tapered sheet surface and the spherical contact surface is, for example, 11 mm,
It is set to substantially match the sliding diameter of the movable iron core 4 and the vibrator 7. Note that the valve seat 13 and the valve 14 are made of polybutylene terephthalate (PBT), for example.
).

The axis of the movable core 4 is electrically connected in order to balance 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 hole 4b is provided. This conduction hole 4b is
The maximum diameter is set to be 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.

As a result, as shown in FIG. 3, sealing performance is ensured when the duty is zero, and flow characteristics without hammering noise or abnormal phenomena are obtained. Furthermore, since the end of the valve 14 overlaps the end of the vibrator 7 in the direction of the sliding axis so as to cover it from the outside as described above, this proportional flow control valve can be used to control the amount of bypass air in an internal combustion engine. Even if the gas is blown back from the engine, blow-by gas or gas blown back from the engine is prevented from flowing directly into the sliding parts of the valve 14 and the movable core 4, and deposits such as carbon and oil contained in those gases are thereby prevented from flowing directly into the sliding parts of the valve 14 and the movable iron core 4. This prevents it from entering and adhering to moving parts.

Furthermore, in this embodiment, the solenoid device 1 is
and the proportional flow rate control valve body 11 are fitted together without play through the guide member 19, so that misalignment of the abutting portion between the valve assembly 18 and the valve seat 13 is caused by the clearance between the movable iron core 4 and the vibrator 7. Valve assembly 1
Moreover, as mentioned above, the seat surface of the valve seat 13 is tapered, and the valve I
Since the abutment surface of No. 4 is spherical, even if the above-mentioned collapse occurs, sealing performance is ensured by abutting with the abutment portion of a predetermined diameter. The sliding clearance between the movable iron core 4 and the vibrator 7 is 0.02 to 0.2 mm, and the ratio L/D between the sliding length L and the sliding diameter is 15 or more.

Furthermore, in this embodiment, as described above, the valve seat 13
Since the contact circle diameter between the valve 14 and the movable iron core 4 is approximately the same as the sliding diameter between the movable iron core 4 and the vibrator 7, even if negative pressure in the intake pipe is applied to the fluid outlet passage IIC 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.

The holder 16 can be fixed to the movable core 4 by press-fitting, or can also be fixed by adhesion or caulking. Further, a smaller diameter portion may be provided at the tip of the reduced diameter portion 4c of the movable core 4 to fix the holder.

Further, the contact portion between the valve 14 and the valve seat 13 may be such that the valve 14 has a multi-stage conical contact surface, and the valve seat 13 has a spherical seat surface.

Furthermore, the overlapping structure of the ends of the valve 14 and the vibrator 7 is such that the valve 14 is on the inside,
The vibrator may be placed on the outside.

[Effects of the Invention] As described above, according to the present invention, a valve assembly is constituted by a movable iron core, a valve, an elastic body, and a holder, and this is biased by a return spring and slidably supported by a cylindrical member. By overlapping the end of the valve and the end of the opposing cylindrical member in the direction of the sliding axis, it is possible to eliminate leakage when fully opened and ensure sealing performance. When the flow rate is controlled by dither control or dither control, it is possible to absorb the repulsive force caused by the collision during unseating or seating, which is caused by these controls, and eliminates hammering noise and abnormal phenomena in flow characteristics. In air volume control, etc., blow-by gas from upstream of the intake passage and blowback gas from the engine from downstream are prevented from flowing directly to the sliding part between the valve and the movable iron core, and carbon, oil, etc. contained in these gases are prevented. It is possible to prevent deposits from adhering to the sliding portion and maintain good slidability of the parts of the valve assembly. Therefore, it is possible to obtain a highly reliable proportional flow rate control valve with a fully closing function, which does not cause tapping sounds or abnormal phenomena caused by poor sliding, and can eliminate over-rotation and runaway caused by it.

[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. FIG. 5 is a longitudinal sectional view of the control valve, FIG. 5 is a flow rate characteristic diagram thereof, and FIG. 6 is a typical steam flow characteristic diagram of a conventional poppet type valve. In the figure, ■ is a solenoid device, 2 is a defined iron core, 3 is a case, 4 is a movable iron core, 4C is a reduced diameter part, 5 is a return spring, 6 is an electromagnetic coil, 7 is a vibrator (cylindrical member),
11 is a proportional flow rate control valve body, lla is a fluid introduction passage, ], 1c 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 toward the valve seat is fixed to the movable core, and the movable core, the valve, the elastic body, and the holder are urged by the return spring and slid by the cylindrical member. 1. A proportional flow rate control valve comprising a dynamically supported valve assembly, wherein an end of the valve and an end of the cylindrical member opposing the valve are overlapped with each other in a sliding axis direction.