JPS597661Y2 - Stroke error absorption valve - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a valve that alternately opens and closes, for example, an air vent passage and a canister passage of a carburetor, and can absorb stroke errors during opening and closing.

In general, this type of valve normally uses the valve seat surface on the canister side as a stopper to maintain airtightness when switching in the canister passage blocking direction. For valves whose stopper is the limit point of movement, even though the limit point of movement has been reached, there is a gap between the valve seat and the valve seat surface due to variations due to errors in machining, assembly, etc. There was a concern that as a result, it would be impossible to maintain airtightness in the valve closed state.

Therefore, in order to absorb the stroke error in which airtightness cannot be maintained between the valve and the valve seat surface even when the valve reaches its travel limit, the valve itself is made of a flexible material, which reduces the closing force of the valve. In order to compensate for this, and to give the valve seat stroke a wider width, a flexible cylindrical rib with a gradually larger diameter on the valve seat surface side on the canister side is integrated. If the valve is shaped like an umbrella, when negative pressure is applied to the valve from the outside, the cylindrical rib will be sucked out in the expansion direction, resulting in a loss of airtightness with the seat surface.

This idea was made to solve the above problems all at once.The purpose is to fully absorb the stroke error and close the valve even if there is some variation in the seat stroke in the direction of shutting off the fluid passage. With a simple structure, the stroke error absorbing valve has a shape that ensures airtightness with the seat surface at all times, and in that state, the seat force increases even more when negative pressure is applied from the outside. It is about providing.

Hereinafter, an embodiment in which this invention is applied to a carburetor will be described with reference to the drawings. 1 is a carburetor, 2 is an intake passage, 3 is a float chamber, and 4 is a throttle provided in the intake passage 2. A main nozzle 6 which communicates with the float chamber 3 and opens on the upstream side of the throttle valve 4 in the intake passage 2;
is a choke valve provided on the upstream side of the main nozzle 5, 7
is an air vent passage, and this air vent passage 7 communicates the intake passage 2 and the float chamber 3 via a valve chamber 8 and a passage 9.

10 is a canister (evaporated fuel adsorption device); 11 is a canister passage; this canister passage 11 communicates with the valve chamber 8 via a diaphragm chamber 12, a passage 13, and a valve hole 14.

15 is a diaphragm, which has a diaphragm chamber 12 and a pressure chamber 1.
6, and the base end of a valve shaft 17 is connected to the center of the diaphragm 15.

This valve shaft 17 loosely passes through the inside of the valve hole 14, and its tip end is connected to the valve chamber 8.
The valve shaft 17 extends inward, and a flow path switching valve 18 is attached to the tip of the valve shaft 17.

As shown in detail in FIG. 2, this valve 18 has a valve seat surface 1 of the valve hole 14 on the periphery of a valve body 20, which is formed by covering a metal reinforcing plate 19 with a rubber-like elastic material.
4. A tapered or inverted umbrella-shaped sleeve valve portion 21 that protrudes toward the a side and gradually becomes smaller in diameter on the protruding end side is integrally formed with the same elastic material as the outer jacket of the valve body 20,
In addition, an inner annular rib 22 is integrally formed on the peripheral edge of the opening end of the sleeve valve portion 21, and an outer annular rib 2 is also formed on the end surface of the valve body 20 on the opposite side from the sleeve valve portion 21.
3 is integrally protruded.

The valve 18 having such a shape and structure has a spring 2.
4 constantly biases the air vent passage 7 in the direction of closing.

25 is a solenoid housed in the pressure chamber 16, 26 is a solenoid adsorption surface, 27 and 28 are negative pressure introduction pipes, 29
is a key switch.

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

First, when the engine is started, the negative pressure introduction pipes 27 and 28
An intake negative pressure is generated in the pressure chamber 16 through the diaphragm 15, thereby pulling the diaphragm 15.

In this case, the solenoid 25 is naturally excited, and a magnetic force is generated on the solenoid attraction surface 26.

Therefore, when the diaphragm 15 is pulled as described above, the suction target plate 15a is attached to the solenoid suction surface 26.
Thereafter, the diaphragm 15 remains attracted to the solenoid attraction surface 26 via the attraction plate 15a until the current supply to the solenoid 25 is cut off.

In such a state, the valve 18 moves to follow the diaphragm 15 against the spring 24, and the sleeve valve portion 2
The inner annular rib 22 at one tip is pressed against the valve seat surface 14a to maintain airtightness with the valve seat surface 14a.

Therefore, in this state, the air vent passage 7 is in communication with the inside of the float chamber 3.

On the other hand, when the energization to the solenoid 25 and the supply of negative pressure to the pressure chamber 16 are cut off, the valve 18 moves away from the seat surface 14a and closes the air vent passage 7 due to the biasing force of the spring 24. Float chamber 3 communicates with canister 10.

As explained above, this design has a tapered or inverted umbrella shape in which the valve body protrudes in the opposite direction to the direction in which it is sucked in the opening direction due to the pressure difference on both sides in the closed state, and the diameter of the protruding end gradually becomes smaller. A sleeve valve part made of an elastic material is provided, and an inner annular rib shaped at the periphery of the opening end of the sleeve valve part is pressed against the seat surface. Therefore, even if there is a slight variation in the seat stroke, the error in the seat stroke can be reliably absorbed by the sleeve valve portion, and furthermore,
This sleeve valve part has a tapered or inverted umbrella shape in which the diameter of the opening end gradually decreases as described above.
When a negative pressure is generated from the outside while the sleeve valve portion is pressed against the valve seat surface, the sleeve valve portion expands, and the seating force becomes stronger, thereby reliably maintaining airtightness with the seat surface.

In addition, by integrally forming an inner annular rib on the opening periphery of the sleeve valve portion, the rigidity of the opening end periphery is improved, and even when the valve stroke becomes large, the protruding end does not bend in a wave-like manner. It is possible to eliminate the formation of a gap between the contact surface and the contact surface, and maintain the crimped state between the protruding end and the valve seat.

Further, by using a combination of a diaphragm and a solenoid as the operating mechanism for press-fitting the sleeve valve portion to the valve seat surface, fluctuations during valve operation can be eliminated and the valve can always be closed stably.

[Brief explanation of drawings]

The drawings show an embodiment of this invention, and FIG. 1 is a cross-sectional explanatory diagram of the carburetor, and FIG. 2 is an enlarged sectional view of the essential parts thereof. 14a...Seat surface, 18...Valve, 20...Valve body, 21...Sleeve valve portion, 22...Inner annular rib .

Claims (1)

[Scope of utility model registration request] In a valve that is sucked in the opening direction due to the pressure difference on both sides of the closed position when the fluid passage is closed, the valve body has a tapered shape that protrudes in the opposite direction to the suction direction and that the protruding end side gradually becomes smaller in diameter. Alternatively, a stroke error absorbing valve characterized in that a sleeve valve portion made of an elastic material in the shape of an umbrella is integrally provided, and an inner annular rib is integrally formed on the peripheral edge of the opening end of the sleeve valve portion.