JPS6332473Y2 - - 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. It has a valve body and a solenoid that controls the position of the valve body, and _the amount of energization of the solenoid 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. There are some devices that control the flow of air and thereby control the amount of air flowing.

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 extremely difficult to set the flow rate characteristics of the valve relative to the solenoid 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. There is a problem 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. The load caused by the pressure difference between the back and front of the valve body is removed, and the opening between the valve body and the valve seat, that is, the amount of air flowing, is controlled by the solenoid current value and the return spring of the valve body. It is conceivable to make it possible to control the temperature accurately.

The bellows in the air control valve mentioned above is designed to minimize the influence on the flow rate characteristics determined by the solenoid and return spring by making the spring constant in the axial direction of the bellows as small as possible. Must not be deformed due to differential pressure between the suction port and the air discharge port, be able to withstand sudden pressure changes due to backfire, etc., be able to follow the rapid movement of the valve body and have long-term durability and reliability, and be able to withstand high temperatures. The creep that occurs after a certain period of time under strain in an atmosphere of characteristics are required.

In particular, the valve body only needs to have one vent hole of an appropriate diameter, but dust in the air, carbon particles in the exhaust gas, etc. may pass through the valve body during use. There is a risk that the pores may become clogged, resulting in decreased response of the valve due to pressure adjustment of the bellows and compression of air within the bellows. As a countermeasure to this problem, it may be possible to enlarge the diameter of the ventilation hole.

However, the valve body is made of fluororesin such as Teflon (trademark) and is formed integrally with the bellows.
This is preferable in terms of the above-mentioned properties and heat resistance and oil resistance. Therefore, if the diameter of the vent hole is increased, there is a risk that the surface that contacts the valve seat will be distorted.

This invention was developed in view of the above problems, and it is equipped with a valve body that prevents bellows pressure adjustment and valve response from decreasing due to clogging of the vent hole, and does not cause distortion of the valve seat contact surface. The purpose of this invention is to provide an air control valve.

This invention consists of an air suction port, an air discharge port, a valve seat provided between the air suction port and the air discharge port, a valve body that is in contact with and separate from this valve seat and measures the circulating air, and An air control valve having a solenoid that controls the position of the valve body includes a bellows that forms a sealed space at the rear of the valve body, and a passage formed in the valve body that communicates the sealed space with a space on the front side of the valve body. pores, and the ventilation holes,
The above objective is achieved by setting the diameter to 0.7 mm or more without distorting the valve body seat surface, and by providing two or more valves.

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

This embodiment includes an air suction port 1, an air discharge port 2, a valve seat 3 provided at a position between these air suction port 1 and air discharge port 2, and a valve seat 3 that is in contact with and separate from this valve seat 3 and that allows air to flow through the valve seat 3. In an air control valve V having a valve body 4 for metering and a solenoid 5 for controlling the position of the valve body 4, a solenoid 5 is formed integrally with the valve body 4 on the opposite side of the valve body 4 to the valve seat 3. , and a bellows 7 forming a sealed space 6 at the rear of the valve body 4.
A vent hole 9 is formed in the valve body 4 and communicates the sealed space 6 with the space 8 on the front side of the valve body, and the diameter of the vent hole is set within a range that does not distort the valve body seat surface.
The diameter should be 0.7 mm or more, and two pieces should be provided.

The valve seat 3 is press-fitted into the housing 10, and a valve lip 11 made of an elastic material such as rubber is baked into the inner corner of the valve seat 3 facing the valve body 4 (see Fig. 2). reference).

The valve body 4 is integrally formed of the same material as the bellows 7, and is connected to the flange 12A by a bellows holder 13 that is press-fitted into the tip of a shaft 12 that passes through the center of the bellows 7 in the axial direction. is fixed between.

The shaft 12 extends into the stator core 15 through the rear end opening 14 of the bellows 7, and contacts the outer periphery of a moving core 16 press-fitted into the shaft 12 at a position adjacent to the rear side of the bellows rear end opening 14. The stator core 15 is supported by a bearing bush 17 and a bearing bush 18 disposed inside near the rear end of the stator core 15 so as to be movable in the axial direction within a certain range.

A rear end portion of the stator core 15 is provided with a yoke 20 that encloses and supports the bobbin 19 of the solenoid 5.
It is provided with a screw hole 22 that protrudes rearward from the rear end, is coaxial with the shaft hole 21 in which the shaft 12 is disposed, and opens at the rear end. An adjusting screw 2 is inserted into this screw hole 22 from the rear end.
3 are screwed together, and the tip projection 24 of the adjusting screw 23 and the shaft 12
The set length of a return spring 26 interposed between the rear end projection 25 and the return spring 26 is adjusted, thereby adjusting the urging force in the direction in which the tip of the shaft 12 protrudes. A sealing material is applied to the outer periphery of the adjusting screw 23 to prevent it from loosening and to maintain airtightness.

A bearing bush 17 that contacts the outer periphery of the moving core 16 is supported on the inner periphery of a magnetic plate 27. The magnetic plate 27 is fastened to the end surface of the housing 10 on the solenoid 5 side at a flange 27B together with the flange 20A of the yoke 20 by bolts 28. Reference numeral 27A indicates a communication hole formed in the magnetic plate 27 and communicating the front and rear spaces thereof.

In other words, the yoke 20 includes the bobbin 1
9 and the magnetic plate 27 with the bolt 28.
It is tightened and fixed in the direction of pressing against the end surface of the housing 10. Reference numeral 29 in the figure indicates an O-ring disposed between the rear end of the bobbin 19 and the yoke 20, and 30 indicates an O-ring disposed at the contact portion between the outer periphery of the tip of the bobbin 19, the inner circumferential surface of the yoke 20, and the magnetic plate 27. , 31 is yoke 2
0 flange 20A and magnetic plate 27
O-rings arranged on the contact surfaces of the solenoid 5 are shown, thereby preventing water from leaking into the solenoid 5 portion.

The front end 27C of the magnetic plate 27 protrudes into the bellows arrangement space 32 in the housing 10, and the bellows 7 is inserted between the magnetic plate 27 and a stepped portion 32A formed in the bellows arrangement space 32 via a packing 33. The thick rear end portion 7A is sandwiched therebetween. Therefore, the bellows 7 isolates the sealed space 6 inside the bellows 7 from the bellows arrangement space 32 (air discharge port 2). Number 3 in the diagram
Reference numeral 4 indicates a ring-shaped rubber cover attached to the outer periphery of the rear end of the yoke 20, and a thermosetting resin is filled in the space between the inner periphery of the rubber cover 34, the rear end of the stator core 15, and the outer periphery of the rear end of the yoke 20. The terminal 36 is
A portion of the lead wire 37 is molded in an insulated state. In addition to the waterproof function, the O-rings 29 and 30 have a waterproof function.
It has a function of preventing the liquid from entering the yoke 20 and flowing into the stator core 15 side. In addition, the reference numeral 38 in the figure is a varnish tube, 39 is an air control valve mounting bracket, 40 is a bolt, 4
1 indicates a spring washer.

In the above air control valve, when a current is applied to the solenoid 5 via the lead wire 37, the magnetic field generated thereby passes through the stator core 15, the yoke 20, the magnetic plate 27, and the moving core 16. A loop is formed between the stator core 15 and the moving core 16, and suction force is generated between the stator core 15 and the moving core 16.

Therefore, the shaft 12 and bellows 7 together with the moving core 16 are connected to the return spring 26.
It resists and is attracted depending on the strength of the magnetic field. Therefore, the valve body 4, which is the tip of the bellows 7, and the valve lip 11 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 6 in the bellows 7 is communicated with the space 8 on the front side of the valve body 4 through the vent hole 9 formed in the valve body 4, so the pressure between the two is the same, and therefore the suction No load is applied to the valve body 4 in the axial direction due to the pressure difference between the side and the discharge side, and the opening degree of the valve body 4 and the valve seat 3, that is, the amount of air flowing through it, is determined by the current value to the solenoid 5 and the return spring 26. It will be determined only by the relationship with The air flow rate can thus be made proportional to the current to the solenoid 5.

The hole diameter of the ventilation hole 9 is 0.7 mm or more, which was experimentally determined to prevent dust and carbon particles from clogging the air, and two holes were provided in case the hole becomes clogged. .

Therefore, even if the shaft 12 and the valve body 4 reciprocate due to the application or extinction of current to the solenoid 12, and air enters and exits the closed space inside the bellows 7 from the ventilation hole 9, the ventilation hole 9 The bellows 7 will not become clogged and the function of the bellows 7 will not deteriorate.

Since the present invention is configured as described above, it has the excellent effect of preventing the function of the bellows from deteriorating due to clogging of the vent hole of the valve body and maintaining the responsiveness of the valve.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of an air control valve according to the present invention, and FIG. 2 is a cross-sectional view showing an enlarged main part of the same embodiment. V... Air intake port, 2... Air discharge port, 3... Valve seat, 4... Valve body, 5... Solenoid, 6... Sealed space, 7... Bellows, 8
...Valve body front side space, 9...Vent hole.

Claims (1)

[Scope of utility model registration request] An air intake port, an air discharge port, a valve seat provided at a position between these air intake ports and air discharge ports, a valve body that is in contact with and separate from this valve seat to measure circulating air, and the position of this valve body An air control valve having a solenoid for control, comprising: a bellows forming a sealed space at the rear of the valve body; and a vent hole formed in the valve body and communicating the sealed space with a space on the front side of the valve body. An air control valve characterized in that the air control valve is provided with two or more vent holes, and has a diameter of 0.7 mm or more within a range that does not distort the valve body seat surface.