JPS5817175Y2 - Three-port type voice coil type flow rate proportional control valve - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a three-boat type voice coil type flow rate proportional control valve that operates accurately without being affected by the dynamic pressure of fluid.

A three-boat type voice coil type flow rate proportional control valve, which uses an electromagnetically operated linear motor to open and close a slide valve to control the flow rate, can feed a flow rate that is approximately proportional to the applied current value, so for example, , used in automobile engine exhaust gas purification systems, etc.

When using this type of control valve in this exhaust gas purification system, the input port of the voice coil type flow rate proportional control valve is connected to the air pump, and the output port is connected to the upstream side of the three-way catalyst in the exhaust system. The current applied to the voice coil type flow rate proportional control valve is changed by signals according to pressure, rotation speed, etc., and the voice coil type flow rate proportional control valve distributes the air necessary to achieve the best exhaust gas concentration for the catalyst. This allows air to be supplied to the purification system.

As a three-boat type voice coil type flow rate proportional control valve that requires such an operation, there is an invention in Japanese Patent Application No. 53-58108 related to the applicant's earlier application, which is shown in Fig. 4. As shown in FIG. 5, the total passage cross-sectional area of the second communication hole 29 and the passage cross-sectional area of the earth passage 100' formed by the two permanent magnets 24 and 25 second end faces and the magnetic yoke 26 are as follows. Almost equal.

With this conventional control valve, there is no problem when the amount of fluid flowing in from the input port 11 is small, but when the flow rate is large, the relationship between the flow rate of the first output port 12 and the current is indicated by the dotted line 1' in FIG. [Also, when the pressure of the fluid from the input port 11 is small, the relationship between the flow rate and the current is as shown by the dotted line 2'
1, and there is a large deviation (symbol x) in the characteristics between 1' and 2', and there is a problem that accurate proportional control cannot be performed.

This is because when the flow rate of the fluid flowing in from the input port 11 increases, the flow rate of the fluid flowing through the air passage 100' increases [one dotted line in Fig. 3, the bobbin 22 is connected to the spring holding portion 22a of the air passage 100'. It receives a strong force in the valve opening direction due to the influence of the dynamic pressure of the fluid.

When this force increases, the slide valve 27 is moved by the spring 31.
32 and moves in the valve opening direction.

To explain this based on FIG. 3, it has been experimentally confirmed that a flow rate as shown by symbol Q occurs when the current is zero.

This means that a flow rate that is not proportional to the signal sent to the voice coil flows out from the first and second output ports 12 and 14, and the flow rate of the fluid flowing in from the input port 11 is large, and This means that when the flow rate of 100' is high, accurate control valve operation cannot be obtained.

Therefore, the technical object of the present invention is to prevent the flow velocity of the fluid in the air passage from increasing even if the amount of fluid flowing in from the input port increases.

The technical means of the present invention taken for this purpose is to create a space between the input port and the outer periphery of the second communication hole (hereinafter referred to as the second This is because a bypass passage is provided that directly communicates with the inlet chamber (referred to as the inlet chamber).

This means works as follows.

That is, when fluid is supplied from the input port, the fluid first divides into the air passage and the bypass passage, then joins in the second inflow chamber, and further, after the flow rate is controlled by the slide valve, the fluid flows into the air passage and the bypass passage. is sent from the communication hole to the second output port.

Therefore, the flow rate of fluid flowing through the air passage is significantly smaller than that of the conventional system, so even if the flow rate of fluid from the input port increases, the flow rate of fluid within the air passage does not increase.

In the three-port type voice coil proportional flow rate control valve according to the present invention, when the flow rate of fluid from the input port is large, the relationship between the flow rate and the current is as shown by solid line 1 in Figure 3, and the flow rate of fluid from the input port is When the flow rate is small, the relationship between the flow rate and the current is as shown by the solid line 2 in FIG.

As is clear from FIG. 3, the difference in characteristics (symbol Y) between the solid lines 1 and 2 is small.

The present invention produces the following unique effects.

That is, since the air passage in the conventional magnet is small, the above-mentioned technical problem of the present invention can also be solved by cutting out a part of the pair of permanent magnets in the circumferential direction to enlarge the air passage. However, this conversely reduces the width of the working surfaces of the pair of permanent magnets, weakening the magnetic force.

In contrast, in the present invention, since the bypass passage is provided between the magnetic yoke on the outer periphery of the moving coil type linear motor and the inner surface of the case, the bypass passage can be formed by reducing the size of the magnetic yoke support part of the case. can be made as large as necessary, without sacrificing the width of the working surface of the permanent magnet.

Also, by reducing the fluid flow velocity in this way,
Even if iron powder generated in the air pump is mixed into the inflowing fluid, the flow velocity in the air passage and bypass passage is reduced, so the iron powder is easily attracted to the magnetic yoke, and the surface of the permanent magnet is・It is possible to reduce the possibility of the iron powder adhering to the outer periphery of the hollow iron core and obstructing the smooth movement of the slide valve in the left and right direction, and to prevent the iron powder from flowing into the equipment connected to the second output port. can.

An embodiment of the present invention will be described.

A three-port type voice coil type proportional flow rate control valve 1 shown in FIG. 1 has a case 4 having an input port 2 and a first output port 3, and a moving coil type linear motor 5 is accommodated in the case 4. be done.

A cover 7 having a second output port is integrally connected to the side opening of the case 4 with bolts 8 .

A slide valve 9 housed in the case 4 is actuated and displaced by a linear motor 5 to direct fluid from the manual port 2.
selectively controlling the flow to the first output port 3 and the second output port 3;

The moving coil type linear motor 5 has a hollow core 10 arranged concentrically with the axes of the first and second output ports 3 and 6. It is divided into a first output chamber 12 and a second output chamber 13.

The first output chamber 12 communicates with the first output port 3 and
The cylindrical wall of the hollow core 10 forming the output chamber 12 has a first
A communication hole 14 is provided.

The second output chamber 13 communicates with the second output port, and a second communication hole 15 is provided in the cylindrical wall of the hollow core 10 forming the second output chamber 13 .

A hollow iron core 10 is provided with an electromagnetic coil 16 made of a non-magnetic material.
A bobbin 17 wound with is slidably disposed.

A pair of permanent magnets 23 are arranged so that magnetic flux passes in a direction perpendicular to the windings of the electromagnetic coil 16.

A magnetic yoke 18 that forms the magnetic circuit of the permanent magnet 23 together with the iron core 10 is arranged along the inner wall of the case 4.

The bobbin 17 receives the urging force of the coil springs 19 and 20, and when no current is applied to the electromagnetic coil 16, the bobbin 17 is located on the left side as shown in FIG.
A slide valve 9 located between and fixed to the bobbin 17 closes the first communication hole 14 that communicates the first output chamber 12 and the input port 2.

In this state, the second communication hole 15 in the cylindrical wall of the iron core forming the second output chamber 13 is open, and the input port 2 is open.
The fluid from the bypass passage 22 and the inflow chamber 20, which will be described later,
0, is discharged from the second output port through the second communication hole 15 and the second output chamber 13.

An input port 2 and a second
A bypass passage 22 is provided that directly communicates the space around the outer periphery of the communication hole 15, that is, the inflow chamber 200.

As shown in FIG. 2, three bypass passages 22 are arranged so as to communicate with each other.

Furthermore, it has been confirmed through experiments that the total passage cross-sectional area of the bypass passage 22 is preferably at least twice as large as the total passage cross-sectional area of the first or second communication holes 14 and 15. .

The fluid flowing in from the input port 2 flows through this bypass passage 2.
Entering 2, pressure adjustment is required.

For this reason, for example, the pressure at input port 2 increases,
Even if the fluid flow rate increases, the flow rate decreases in this bypass passage 22, so the influence of dynamic pressure on the bobbin 17 is reduced.

Therefore, there is no unexpected operational displacement of the bobbin 17, and the slide valve 9 can operate according to the signal given, so that the valve can operate accurately.

When the current is not energized as shown in FIG.
However, when a current is applied to the electromagnetic coil 16, a force proportional to the current value is generated in the right direction as seen in FIG. 1 according to Fleming's left hand rule, and the bobbin 17 is The slide valve 9 is actuated and displaced to the right against the biasing force, and the first communication hole 14 is opened by an amount corresponding to the applied current value, and the bypass passage 2 is opened from the input port 2.
2. Allows fluid to flow to the first output port 3 via the air passage 100, the first communication hole 14, and the first output chamber 12.

The actuation displacement of the slide valve 9 that is proportional to the current applied to the electromagnetic coil 16, ie, the opening degree of the first communication hole 14, allows a controlled predetermined flow rate to flow into the first output port 3.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of a control valve according to an embodiment of the present invention, Fig. 2 is a sectional view taken from arrow II-II in Fig. 1, and Fig. 3 is a diagram showing the current relationship between the control valve of the present invention and the conventional control valve. A graph showing the relationship between fluid flow rates, FIG. 4 is a side sectional view of a conventional control valve, and FIG. 5 is a sectional view taken from arrow AA in FIG. 4. In the diagram: 1... Control valve, 2... Input port, 3, 6... Output port, 4... Case, 5...・Moving coil type linear motor, 9・
...Slide valve, 10...Hollow iron core, 14...First communication hole, 15...Second communication hole, 17...・Bobbin, 18...
・Magnetic material yoke, 22...Bypass passage, 10
0...Air passage, 200...Inflow chamber.

Claims (1)

[Scope of utility model registration request] A movable coil type linear monitor housed in a case having an input port and two output ports serves as a slide valve for opening and closing the first and second communication holes of the hollow core that constitutes the movable coil type linear motor. and a bobbin fixed to the slide valve to control communication between the input port and the two output ports, the outer periphery of the moving coil linear motor. A three-boat type voice coil type proportional flow rate control valve, which is provided with a bypass passage that directly communicates the input port and the second inflow chamber between the magnetic yoke of the part and the inner surface of the case.