JPS6069380A - Exchange valve device - Google Patents

Abstract

PURPOSE:To integrate a solenoid valve and a temperature-sensitive exchange valve by providing a shaft having a projection contactable with the valve body upon sucking into an inner core and a shape-memory alloy spring for energizing the valve body in open direction. CONSTITUTION:When power is not supplied to a solenoid coil 44 and the temperature in carburetor float chamber is low, the load is set higher than the energizing force of a shape-memory alloy second spring 39 to hold the valve body 36 at closed position by means of first spring 37. Upon temperature rise, the second spring 39 will extend to the stored shape and when the load exceeds over the energizing force of spring 37, the valve body 36 is opened by the spring 39 to communicate between the inlet and outlet ports 32, 33. When power is fed to the solenoid coil 44, the projection 48 will contact through the inner core 42 of shaft 47 against the valve body 36 to close the valve.

Description

[Detailed Description of the Invention] [Object of the Invention] The present invention relates to a switching valve device, and more particularly to a switching valve device that controls opening and closing of a fluid passage in response to an input current signal and an ambient temperature signal. It is.

[Field of application of the present invention]

INDUSTRIAL APPLICABILITY The present invention is applied to a carburetor auxiliary vent control device and the like for preventing fuel evaporative gas generated in a carburetor float chamber of an automobile engine from being released into the atmosphere.

[Prior art]

An example of a conventional device for preventing the release of fuel evaporative gas into the atmosphere in an automobile engine, that is, a carburetor outer vent control, is shown in FIG. In the device 10 shown in the drawings, the illustrated state is when the engine is stopped, but when the engine ignition switch 11 is turned on for engine operation, the solenoid 13 is energized from the battery power source, and the solenoid valve 14 is closed to the fuel evaporative gas passage. 15 will be closed. This solenoid valve is of a normally open type that opens when the switch 11 is turned off, so that the fuel vapor generated in the carburetor float chamber 16 is not adsorbed by the canister 17 during engine operation. In this case, the fuel vapor is supplied to the engine from the inner vent tube 18 through the intake passage 19 of the capretor and is combusted.

Next, when the engine is stopped, the current in the solenoid 13 is stopped and the solenoid valve 14 is opened. However, since the engine atmosphere is still hot at this time, the fuel in the float chamber 16 evaporates, and this evaporated fuel gas , fuel evaporative gas passage 15
The canister 1 is connected to the canister 1 via the solenoid valve 14 inside, and via the temperature-sensitive switching valve 20 that opens at high temperatures (approximately 50°C or higher) and closes at low temperatures.
7 and prevents the fuel gas from being released into the atmosphere.

Now, after a certain period of time has passed after the engine is stopped, the temperature of the engine and engine cooling water decreases, and when this temperature falls below a predetermined value, the switching valve 20 closes and the fuel evaporation gas in the float chamber 16 is adsorbed to the canister 17. However, since the fuel temperature in the float chamber 16 has decreased and fuel evaporation is extremely low, there is no problem even if the adsorption by the canister 17 is interrupted. Note that the reference numeral 21 in the figure is a Caprec throttle valve.

[Problems in the Prior Art and Technical Analysis thereof] However, the conventional device shown in FIG. The temperature-sensitive switching valve 20 that controls the opening and closing of the passage 15 in response to changes in the temperature is configured separately, and as a result, the number of parts constituting the control device 10 increases, making the entire device 10 larger. There has been a problem in that the ease of attachment to the engine is significantly reduced. Furthermore, this temperature-sensitive switching valve 20 operates by sensing the ambient temperature near the carburetor, but this temperature is not the same as the temperature inside the float chamber 16 of the carburetor.
As a result, the outer vent control device 10 has poor operational accuracy with respect to temperature changes, which is a major obstacle to improving operational reliability.

[Technical issues]

Therefore, in view of the above-mentioned problems of the prior art, the technical object of the present invention is to integrate a solenoid valve and a temperature-sensitive switching valve.

[Technical issues]

In order to achieve this technical problem, the present invention forms a fluid passage communicating between the two ports in a body having an inlet port and an outlet port, and a valve body for controlling opening and closing of the passage is disposed in the passage. A first spring biasing the valve body in the closing direction is provided so that the plunger, which is attracted to the inner core when the solenoid coil forming the magnetic circuit is energized by the input current, is positioned in the magnetic circuit. A shaft that is disposed opposite to one end surface of the inner core and has one end fixed to the plunger is passed through the inner core, and the other end of the shaft is made to protrude from the other end surface of the inner core, and the protruding portion of the shaft is connected to the solenoid coil. a second spring that moves together with the plunger to abut the valve body and hold it in the closed position when energized, and biases the valve body in the opening direction against the bias of the first spring; The second spring is made of a shape memory alloy and expands to a memorized shape at high temperatures, and the solenoid coil.

A technical means is provided for arranging the first spring and the second spring in this order in the axial direction within the body.

[Effect of technical means]

When the solenoid coil is not energized, that is, when the electromagnetic mechanism is not activated, the valve body is activated by balancing the biasing forces of the first spring and the second spring. When the temperature of the carburetor float chamber is low, the valve body is held in the closed position by the biasing force of the first spring whose load is set larger than that of the second spring, and the valve body is communicated with the inlet boat and the canister which communicate with the carburetor float chamber. Communication with the exit port is closed. Additionally, in this case, when the temperature of the carburetor float chamber rises and becomes high temperature, the second spring expands to the memorized shape, and the valve body opens due to the biasing force of the second spring, whose load is greater than that of the first spring, and both valve bodies are opened. Since there is communication between the boats, there is communication between the caplet float and the canister.

Next, when the solenoid coil is energized, that is, when the electromagnetic mechanism is activated, the shaft fixed to the plunger moves together with the plunger, and the protruding part of the shaft from the inner core comes into contact with the valve body, causing the valve body to move. Because it is held in the closed position,
When energized, the valve body can be held in the closed position regardless of temperature changes, and communication between both boats is closed, and communication between the capacitor float chamber and the canister is cut off.

In this way, the present invention integrally assembles the shaft, which is interlocked with the operation of the electromagnetic mechanism via the plunger, and the second spring made of a shape memory alloy, which is memorized to expand at high temperatures, to form a valve body. Since it has a configuration that controls opening and closing, it is easy to install in the carburetor float chamber, and the number of component parts can be reduced compared to conventional equipment, making the equipment lighter and more compact, as well as reducing costs. and has achieved its intended purpose.

[Special effects produced by the present invention]

The second spring made of a shape memory alloy employed in the configuration of the present invention can be set to have a relatively large amount of elongation to elongate into a memorized shape at high temperatures. Therefore, compared to the technical means of using a bimetallic disk as a temperature sensing function, since the bimetallic disk has a small amount of reverse displacement, the present invention makes it possible to set a large stroke amount for opening and closing the valve body. can. the result,
This has the effect of reducing the flow resistance when the valve body is opened, improving the flow performance, and making it possible to apply it to a system for controlling a large flow rate of fluid.

Furthermore, when integrating a solenoid valve and a temperature-sensitive switching valve, which is a problem of the present invention, special care must be taken to prevent the influence of heat generated by the solenoid coil of the solenoid valve from reaching the temperature-sensitive switching valve. However, according to the configuration of the present invention, the solenoid coil, the first spring, and the second spring are arranged in this order in the axial direction within the body,
The second spring is located apart from the solenoid coil. Therefore, the second spring made of a shape memory alloy is not affected by the heat generated by the solenoid coil, so that malfunction of the valve body is prevented and operational reliability can be improved.

〔Example〕

An embodiment embodying the present invention will be described below with reference to FIG.

The switching valve device 30 according to the present invention corresponds to a portion 10' surrounded by a dashed line in the outer control device shown in FIG. The switching valve device 30 includes a resin body 31,
The body 31 is a carburetor float chamber 16 (Fig. 1)
an inlet port 32 communicating with the canister 17 (first
(Figure). Both ports 32,33 are fluid passageways 34 formed within the body 31.
．． 35, and a valve body 36 is connected between the passages 34 and 35.
is provided, and the valve body 36 controls opening and closing between both boats 32 and 33. The valve body 36 is always urged by a first spring 37 in a direction in which it comes into contact with a seat surface 38 formed on the body 31, that is, in a valve closing direction. Further, the valve body 36 is always urged in the open direction by the other end of the second spring 39, one end of which is locked to the body 31. Second spring 39
is made of shape memory metal, and when the temperature is low, the first spring 3
7 is set larger than the second spring 39, and the valve body is held in the closing device as shown. At high temperature (approximately 50℃
(above), since the configuration is such that it expands to a previously memorized shape, at this time the load on the second subring 39 is equal to the first subring 39.
Since it is larger than the spring 37, the valve body seat surface 38
The valve is held away from the valve opening device.

An outer peripheral yoke 40 made of a magnetic material is fixed to the right end of the body 31 in the figure via a rubber seal member 41, and an inner core 42 is disposed on the central axis within the yoke 40. A bobbin 43 made of a non-magnetic material is inserted into the outer periphery of the inner core 42, and a solenoid coil 44 is wound on the hobbin 43. Both ends of the coil 44 are connected to an appropriate power source via a terminal 45. Therefore, when a current is applied to the coil 44, a magnetic circuit is formed by the excitation action of the coil 44, and the plunger 46 is located in the magnetic circuit. At the same time, the plunger 46
It is disposed coaxially with the inner core 42 and opposite the right end surface of the core 42 in the figure, so as to be movable in the axial direction. shaft 47
is fixed to the plunger 46 at one end, and protrudes from the left end surface of the inner core 42 in the figure from the other end. A retainer 49 is fixed to the protrusion 48, and the retainer 4
9 locks one end of the first spring 37.

Now, the above-mentioned solenoid coil 44. First spring 37. Valve body 36. The second springs 39 are arranged in the axial direction within the body 31 in this order, and the second springs 39 are located apart from the solenoid coil 44 . Therefore,
The second spring 39 made of shape memory alloy is no longer affected by the heat generated by the solenoid coil 44. Furthermore, by forming the ring shape to be fitted into the inner core 42, the solenoid coil 44 and the second spring 39 are thermally isolated by the member 50, and the influence of the heat generated by the coil 44 is not exerted on the second spring 39. is prevented.

A rubber cap 51 is fitted around the outer periphery of the yoke 40, and the cap 51 is filled with epoxy resin 52, thereby preventing water from entering the solenoid coil 44 section.

Next, the operation of the above configuration will be explained. First, when the ignition switch 11 (FIG. 1) is off and no current is supplied to the solenoid coil 44, the valve body 36 is moved by the balance of the urging forces of the first spring 37 and the second spring 39. Capleta float chamber 1
When the temperature of spring 6 is low, the load is applied to the second spring 39.
Due to the larger biasing force of the first spring 37, the valve body 36 is brought into contact with the seat surface 38 and held in the closing device. Therefore, since the ports 32 and 33 are cut off, communication between the carburetor float chamber 16 and the canister 17 is closed. Also, in this case, the temperature of the carburetor float chamber 16 rises and becomes high? L<approximately 50°C), the second spring 39 expands to the memorized shape, and the second spring 39 has a larger load than the first spring 37. Due to the biasing force on the right side in the figure, the valve body 36 is seated. Side 3
8 and held in the open position, resulting in both bows 1-32.3
The three spaces are connected.

Next, when the ignition switch 11 is turned on and current is supplied to the solenoid coil 44, a magnetic circuit is formed between the inner core 42 and the magnetic yoke 40 due to the excitation action of the coil 44, and the plunger located in the magnetic circuit 46 is sucked into the inner core 42. Therefore, the shaft 47 fixed to the plunger 46
The protrusion 48 moves to the left in the figure together with the valve body 3.
6 and holds the valve body 36 in a closed device. Like this,
When the coil 44 is energized, the valve body 36 is held in the closed position regardless of temperature changes within the caplet float chamber 16, and communication between the bows 1-32 and 33 is cut off.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing a conventional device for preventing the release of fuel evaporative gas into the atmosphere, and Fig. 2 is a cross section showing an embodiment of the switching valve device according to the present invention applied to the system diagram in Fig. 1. It is a diagram. 30... Switching valve device, 31... Body, 32...
Inlet port, 33... Outlet boat, 34.35...
Fluid passage, 36... Valve body, 37... First spring, 39... Second spring, 42... Inner core,
44...Solenoid coil, 46...Plunger,
47...Shaft, 48...Protruding portion Patent applicant: Reio Nakai, Representative of Lubei Trading Co., Ltd.

Claims (1)

[Claims] A body including an inlet port and an outlet port, a fluid passage formed in the body and communicating between the two boats, a valve body that controls opening and closing of the fluid passage, and a first valve body that biases the valve body in a closing direction.
a spring, a solenoid coil that forms a magnetic circuit by input current, a plunger located in the magnetic circuit and attracted to the inner core when the solenoid coil is energized and placed opposite to one end surface of the inner core, one end of which is fixed to the plunger. a shaft whose other end protrudes from the other end surface of the inner core, and whose protrusion abuts the valve element to hold it in the closed position when the plunger is drawn into the inner core; and a shaft which resists the biasing force of the first spring. and a second spring that biases the valve body in the opening direction, the second spring is made of a shape memory alloy and expands to the memorized shape at high temperatures, and further includes the solenoid coil and the first spring. and a switching valve device in which the second springs are arranged in this order in the axial direction within the body.