JPS6342220Y2 - - Google Patents

Description

[Detailed description of the invention] This invention supplies secondary air to the air control valve, especially the intake system or exhaust system of the engine, to control the air-fuel ratio of the air-fuel mixture to the engine or to control the air-fuel ratio in the exhaust gas from the engine. This invention relates to improvements in air control valves used to control the combustion of residual fuel in exhaust gas by controlling the amount of residual oxygen.

Conventionally, this type of air control valve includes an air intake port, an air discharge port, a valve seat provided between the air intake port and the air discharge port, and a valve seat that is connected to and separated from the valve seat to measure the circulating air. A valve body, a shaft that supports the valve body, a moving core coaxially attached to the outer periphery of the shaft, a magnetic plate that supports the moving core so as to be movable in the axial direction via a bearing, and the shaft. a stator core that is disposed outside at a different position in the axial direction from the moving core and supports the shaft movably in the axial direction via a bearing; Some valves have a solenoid that forms a magnetic loop that passes through the valve, and the position of the valve body is controlled depending on the strength of the magnetic loop. In this case the current to the solenoid is e.g.
It is controlled by a command signal from a control unit based on a signal from a sensor that detects the state of engine exhaust gas, such as an O ₂ sensor.

In the air control valve as described above, if the pressure applied to the air intake port and the air discharge port is large, for example, the pressure difference between atmospheric pressure and engine intake negative pressure is large, the valve body is subjected to force due to this pressure difference. It becomes very difficult to set the flow rate characteristics of the valve in response to the solenoid's current value, and especially when used for engine air-fuel ratio control, there is a delay in the response of the valve body to the energization of the solenoid. The problem is that the fuel ratio cannot be controlled.

In order to solve this problem, in the air control valve as described above, a bellows that forms a sealed space at the rear of the valve body, and a vent hole that communicates the sealed space in the bellows with the space on the front side of the valve body are provided. is installed to remove the load due to the pressure difference between the back and front of the valve body, and thereby the opening between the valve body and the valve seat, that is, the amount of air flowing, is adjusted to the current value of the solenoid and the return spring of the valve body. It is conceivable to make it possible to control the temperature.

However, even in such a control valve, the space between the front and rear surfaces of the magnetic plate and the space between the front and rear surfaces of the stator core bearing are separated by the magnetic plate or the bearing, so that the shaft and the moving core are separated from each other by the magnetic plate or bearing. When reciprocating (response frequency 1 to 4 Hz), the space is compressed or expanded by the magnetic plate or shaft, thereby creating a damping effect on the movement of the shaft,
For this reason, there is a problem in that the accurate response of the shaft and valve body to the signal current to the solenoid is impaired, and therefore, the amount of air cannot be precisely controlled. Particularly when this air control valve is used to control engine exhaust gas, it may cause an emission failure.

This idea was made in view of the above-mentioned conventional problems, and it is an air control valve that responds precisely to the signal current to the solenoid, can control the amount of air flowing, and has excellent durability. The purpose is to provide.

This invention includes an air intake port, an air discharge port, a valve seat provided at a position between the air intake port and the air discharge port, and a valve body that is in contact with and separate from the valve seat and measures the circulating air. a shaft supporting the valve body; a moving core coaxially attached to the outer periphery of the shaft; a magnetic plate supporting the moving core movably in the axial direction via a bearing; and a moving core of the shaft. a stator core disposed outside the core at a different position in the axial direction and supporting the shaft movably in the axial direction via a bearing;
The air control valve has a solenoid that forms a magnetic loop passing through the stator core and the moving core, and controls the position of the valve body according to the strength of the magnetic loop, the air control valve having a sealed space at the rear of the valve body. a vent hole formed in the valve body and communicating the sealed space with the space on the front side of the valve body; and a space formed in the magnetic plate on the rear and front sides of the magnetic plate. The above object is achieved by providing a ventilation hole that communicates with the stator core, and a ventilation hole that is formed in the bearing inside the stator core and communicates with the spaces on both axial end surfaces of the bearing.

Further, the present invention achieves the above object in the above-mentioned air control valve by forming the bearing inside the stator cos as a wound bush, and forming the ventilation hole of the bearing between both ends of the winding bush in the circumferential direction. It is something to do.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in the figure, the present invention includes an air intake port 1, an air discharge port 2, a valve seat 3 provided between the air intake port 1 and the air discharge port 2, and this valve seat. 3
A valve body 4 that moves into and out of contact with and measures circulating air, a shaft 6 that supports the valve body 4, and a moving core 7 that is coaxially attached to the outer periphery of this shaft 6.
a magnetic plate 9 that supports the moving core 7 so as to be able to move in the axial direction via a bearing bush 8; a stator core 11 that supports 6 so as to be movable in the axial direction via a bearing bush 10;
a solenoid 12 disposed outside the stator core 11 and forming a magnetic loop passing through the stator core 11 and the moving core 7;
An air control valve V that controls the position of the valve body 4 according to the strength of the magnetic loop includes a bellows 14 forming a sealed space 13 at the rear of the valve body 4, and a bellows 14 formed on the valve body 4, a ventilation hole 16 that communicates the sealed space 13 with the valve body front side space 15; a ventilation hole 17 formed in the magnetic plate 9 that communicates the rear and front side spaces of the magnetic plate 9; formed in the bearing bushing 10 inside the stator core 11;
A ventilation hole 18 is provided to communicate the spaces on both axial end surfaces of the bearing bush 10.

The bearing bushing 10 in the stator core 11 is a rolled bushing, and the bearing bushing has ventilation holes 1.
8 is formed between both ends of the winding bush in the circumferential direction. (See FIGS. 2 and 3) The valve seat 3 is press-fitted into the housing 19, and a valve lip made of an elastic material such as rubber is provided at the inner peripheral corner of the valve seat 3 facing the valve body 4. 20 is baked in, and the tip of this valve lip 20 is made to touch and separate from the valve body 4 to measure the amount of air flowing.

Further, the valve body 4 may be made of, for example, Teflon (trade name).
A bellows holder 21 is formed integrally with the bellows 14 and is press-fitted into the tip of the shaft 6 passing through the center of the bellows 14 in the axial direction. It is fixed between the shaft 6 and the flange 6A.

The shaft 6 passes through the rear end opening 14A of the bellows 14, passes through a shaft hole 22 formed at the center of the stator core 11, and projects further rearward from the bearing bush 10. The magnetic plate 9 supports the moving core 7 by a bearing 8 at a position adjacent to the rear side of the rear end opening 14A of the bellows.

The rear end of the stator core 11 is press-fitted into the rear end of a yoke 24 that encloses and supports the solenoid 12 and its bobbin 23, and is thereby supported by the yoke 24.

The rear end portion of the stator core is connected to the yoke 24
A screw hole 25 that protrudes further rearward than the rear end and coaxially communicates with the shaft hole 22 is opened at the protruding end, and an adjuster screw 26 is screwed into this screw hole 25 from the rear end opening. are combined.

The tip projection 26 of this adjustment screw 26
A return spring 27 is interposed between the shaft 6 and the rear end projection 6B of the shaft 6, and the return spring 2
The setting length of the shaft 6 is adjusted, thereby adjusting the biasing force in the direction in which the tip of the shaft 6 protrudes. A sealing material is applied to the outer periphery of the adjusting screw 26 to prevent loosening and maintain airtightness.

The magnetic plate 9 is fitted at its stepped portion 9A into a large diameter portion 19B formed on an end surface 19A of the housing 19 on the solenoid 12 side. The large diameter portion 19B is formed coaxially with the valve seat 3 and continuous with the bellows arrangement space 28 in which the bellows 14 is arranged, thereby making the center of the bearing bush 10 of the magnetic plate 9 and the valve seat The centers of 3 are aligned. Also magnetic plate 9
is sandwiched between the flange 24A of the yoke 24 at the flange 9B, and the end face 19A of the housing 19 is secured by the bolt 29.
It is tightened and fixed.

Here, the ventilation hole 1 of the magnetic plate 9 is
7 is formed at a location other than the upper position of the moving core 7, thereby preventing water or foreign matter entering from the ventilation hole 17 from falling onto the moving core 7 or the shaft 6.

Therefore, when the air control valve V is arranged upside down compared to FIG. 1, for example, the lower part in FIG. 1 is located above the moving core 7, so the lower part in FIG. A communication hole 17 is provided in addition to the above.

Further, the thick rear end portion 14B of the bellows 14 is sandwiched between the tip of the stepped portion 9A of the magnetic plate 9 and the inner end of the large diameter portion 19B of the housing 19 via a gasket 30. As a result, the bellows 14 isolates the sealed space 13 inside the bellows 14 from the bellows arrangement space 28.

The ventilation hole 18 of the bearing bush 10 in the stator core 11 is arranged at a location other than the upper position of the shaft 6, so that water, etc. that enters the rear end side of the shaft 6 through the ventilation hole 18 can be removed from the shaft 6. to prevent it from adhering to the If the mounting orientation of the air control valve V changes, the ventilation hole 18 is provided at a location that is not located above the shaft 6 depending on its up and down position.

Reference numeral 31 in the figure indicates a ring-shaped rubber cover attached to the outer periphery of the rear end of the yoke 22, and a space between the inner periphery of the rubber cover 31, the outer periphery of the rear end protrusion of the stator core 11, and the rear end surface of the yoke 22. Filler 3 such as thermosetting epoxy resin to be filled
2, the terminal 33 and a portion of the lead wire 34 are molded in an insulated state.

Further, the reference numeral 35 in the figure is an O-ring disposed between the rear end of the bobbin 23 and the yoke 24, and the reference numeral 36 is between the front end of the bobbin 23, the rear end surface of the magnetic plate 9, and the inner peripheral surface on the front end side of the yoke 24. The O-rings in place are shown. These o-rings 35
and 36 have the function of preventing water etc. from entering into the stator core 11, and also preventing the filler in a fluid state from flowing into the stator core 11 before hardening when filling the filler 32. .

In the figure, reference numeral 37 is a varnish tube, 38 is an air control valve mounting bracket, 39 is a bolt, 40 is a spring washer, and 41 is a flange 9B of the magnetic plate 9 and a yoke 24.
The O-rings disposed between the flanges 24A are shown respectively.

Next, the operation of the above embodiment will be explained.

When a current is applied to the solenoid 12 via the lead wire 34, the magnetic field generated thereby forms a loop through the stator core 11, the yoke 24, the magnetic plate 9, and the moving core 7 to the stator core 11. A suction force is generated between the stator core 11 and the moving core 7. Therefore, the shaft 6 and the bellows 14 along with the moving core 7 are attracted against the return spring 27 according to the strength of the magnetic field. Accordingly, the valve body 4, which is the tip of the bellows 14, and the valve lip 20 of the valve seat 3 are separated, allowing air to flow from the air intake port 1 to the air discharge port 2.

In this case, the sealed space 13 within the bellows 14 is communicated with the space 15 on the front side of the valve body 4 through the vent hole 16 formed in the valve body 4, so the pressure between the two is the same, and therefore the suction No axial load is applied to the valve body 4 due to the pressure difference between the side and the discharge side.

When the valve body 4 reciprocates, the space on the rear side of the magnetic plate 9 and the rear side of the bearing bush 10 is compressed or expanded by the moving core 7 and the rear end of the shaft 6.
Since the space is communicated with the space on the front side of the magnetic plate 9 by 18 and 18, almost no pressure change occurs in these spaces. Therefore, these spaces do not act as a damper, and the opening degree of the valve body 4 and the valve seat 3, that is, the amount of air flowing through them, is determined only by the current value to the solenoid 12 and the relationship with the return spring 27. It turns out. Therefore, the air flow rate can be made exactly proportional to the current applied to the solenoid 12, allowing precise control when used, for example, to control the air-fuel ratio of the air-fuel mixture to the engine.

Further, since the vent holes 17 and 18 are formed at a position other than the upper position of the moving core 7 or the upper position of the shaft 6, the valve body 4
There is an advantage that foreign matter such as water that enters from the ventilation hole 16 through the ventilation holes 17 and 18 does not adhere to the moving core 7 or the shaft 6, so that durability can be maintained.

In the above embodiment, the ventilation hole 18 of the bearing bush 10 is formed straight in the axial direction.
This may also be formed obliquely. In this case, since the sliding surfaces of the bearing bush 10 and the shaft 6 are not affected by the ventilation hole 18, there is an advantage that sliding defects of the shaft 6 are reduced compared to the case where the shaft 6 is linear.

Since the present invention is constructed as described above, it has the excellent effect of being able to control the amount of air flowing with high accuracy in response to the signal current to the solenoid. It also has the effect of minimizing sliding defects of the shaft due to the intrusion of foreign substances such as water.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the air control valve according to the present invention, Fig. 2 is an enlarged sectional view showing the main parts of the same embodiment, and Fig. 3 is a -
It is a sectional view along a line. V...Air control valve, 1...Air intake port, 2...Air discharge port, 3...Valve seat,
4... Valve body, 6... Shaft, 7... Moving core,
8... Bearing, 9... Magnetic plate, 10... Bearing bush, 11... Stator core, 12... Solenoid, 13... Sealed space, 14... Bellows, 15...
Front side space, 16-18...ventilation hole.

Claims (1)

[Claims for Utility Model Registration] (1) An air intake port, an air discharge port, a valve seat provided between the air intake port and the air discharge port, and a valve seat provided in a position between the air intake port and the air discharge port; a valve body that measures the
a shaft supporting the valve body; a moving core coaxially attached to the outer periphery of the shaft; a magnetic plate supporting the moving core movably in the axial direction via a bearing; and a moving core of the shaft. A stator core that is disposed outside the core at a different position in the axial direction and supports the shaft movably in the axial direction via a bearing, and a magnetic loop that is disposed outside the stator core and passes through the stator core and the moving core. an air control valve that controls the position of the valve body according to the strength of the magnetic loop; a vent hole formed in the magnetic plate and communicating the sealed space and the space on the front side of the valve body;
A ventilation hole that communicates between the rear and front spaces of the magnetic plate, and a ventilation hole that is formed in the bearing inside the stator core and that communicates with the spaces on both axial end surfaces of the bearing. Air control valve. (2) The bearing inside the stator core is a wound bushing, and the ventilation hole of the bearing is formed between both ends of the wound bushing in the circumferential direction. Air control valve.