FR3081607A1 - ELECTROMAGNETIC DEVICE - Google Patents

Abstract

The invention relates to an electromechanical device (1), comprising: - a coil (20), - a fixed part formed by a discharge duct (81) - an element (40) movable in the direction of the fixed part (81) for closing the evacuation conduit (81) under the effect of the return force of the spring, characterized in that it includes a noise attenuation system (90).

Description

ELECTROMAGNETIC DEVICE

The present invention relates to electromechanical devices comprising a coil and a movable element under the effect of the magnetic field of the coil, and more particularly but not exclusively the so-called canister bleed solenoid valves used in the automotive field.

The tank of vehicles with internal combustion engines is equipped with an activated carbon filter called a canister which absorbs and retains the fuel vapors coming from the tank.

The canister is connected to the engine intake via a purge solenoid valve which is closed when the engine is stopped and which opens so that the filter can be purged when the engine is running.

EP 1 181442 discloses an example of a purge solenoid valve. Conventionally, the solenoid valve comprises a hollow fixed core made of a ferromagnetic material extending along an axis, a coil mounted around the fixed core and a closure element, movable along the axis of the fixed core under the effect of magnetic field generated by the coil. The shutter member moves to a fixed part of the solenoid valve to close it.

A disadvantage of this type of solenoid valve is that when the shutter member moves to close the solenoid valve, contact between the shutter member and the fixed part causes vibration waves. These vibration waves being due to the shock of the closure element against the fixed part. These vibration waves are a source of noise.

The present invention therefore aims to overcome one or more of the drawbacks of the devices of the prior art by proposing an electromechanical device whose noise is limited.

For this, the present invention provides an electromechanical device comprising:

a coil, a fixed part formed by an evacuation duct an element movable in the direction of the fixed part for closing the evacuation duct under the effect of the return force of the spring, and comprising a noise reduction system .

According to one embodiment of the invention, the noise attenuation system is formed by a permanent magnet disposed at the junction between the fixed part forming the conduit and the movable element, so as to absorb the vibration shocks during closing the duct.

The damping makes it possible to limit the shock during contact between the fixed part and the mobile part when the device is closed, and thus eliminate parasitic acoustic waves.

According to one embodiment of the invention, the noise attenuation system comprises at least two permanent magnets arranged on the one hand, for the first magnet, at the end of the movable element and on the other hand, for the second magnet, at the end of the conduit, opposite one another in order to ensure a magnetic force of contactless braking.

The magnets will repel each other and will thus create a magnetic braking force which makes it possible to manage the docking, that is to say the bringing together of the two parts, mobile and fixed, without shock .

According to one embodiment of the invention, the magnets have a dimension adapted to counter the return force of the spring, of the device, while allowing the closure of the device.

According to one embodiment of the invention, the magnets are circular.

According to one embodiment of the invention, the first magnet has a central opening suitable for the passage of the conduit and the second magnet, has a central opening suitable for the passage of a valve seal.

According to one embodiment of the invention, the magnets are rectangular or square.

According to one embodiment of the invention, the magnets are fixed by any means compatible with the operation of the device.

According to one embodiment of the invention, the device is a canister purge valve.

The invention also relates to the use of the device according to the invention, in a motor vehicle.

Other objects, characteristics and advantages of the invention will be better understood and will appear more clearly on reading the description given below, with reference to the appended figures, given by way of example and in which:

FIG. 1 is a schematic representation of a view in longitudinal section of an electromechanical device according to the invention,

FIG. 2 is a schematic representation of a view in longitudinal section of part of an electromechanical device according to the invention,

- Figure 3 is a representation of the speed of movement of the elements of the electromechanical device, curve a) without noise reduction system, curve b) with noise reduction system according to the invention.

The invention relates to a linear actuator with plunger core or any other actuator magnetically coupling a fixed part with a movable part and involving docking when closing a system requiring sealing in order to ensure in the open position the passage of a fluid and in the closed position blocking this same fluid.

The electromechanical device shown in the form of a solenoid valve 1 shown in Figure 1 is intended to be mounted within a circuit for discharging fuel vapors from a motor vehicle, but the invention is not limited to this application, nor to a solenoid valve.

In the context of the invention, the electromechanical device comprises a noise attenuation system.

According to one embodiment of the invention, the solenoid valve is connected to inlet and outlet conduits, not shown, by means of respective ends 81 and 82. The end piece 82 can be molded with the body 84 of the solenoid valve. , made of plastic, and the end piece 81 with a part 83 which is attached to the body 84 and closes it.

According to one embodiment of the invention, the solenoid valve 1 comprises a connector for its electrical connection, the fixing support 85 of which can be seen in FIG. 1. The solenoid valve 1 is, in the example considered, closed at rest , and opens when powered electrically, for example at a DC voltage between 10 and 15V. The materials of the solenoid valve are chosen to resist hydrocarbon vapors, especially gasoline.

According to one embodiment of the invention, the body 84 of the solenoid valve 1 internally comprises an electromagnetic system. This electromagnetic system comprises a fixed core 10, tubular with axis X, carried at one end by a plate 12 extending perpendicular to the axis X, the core 10 and the plate 12 being made of a soft ferromagnetic material such as by example of iron or ferromagnetic steel. The core 10 and the plate 12 can be made in one piece in a monolithic manner, in particular by machining.

According to one embodiment of the invention, the solenoid valve 1 comprises a coil 20 mounted on a support 21, for example of plastic material, of axis X, this coil 20 extending around the fixed core 10 to generate sound within a magnetic field when electrically powered. The coil 20 is for example made of insulated copper wire, in particular enameled.

According to one embodiment of the invention, an external yoke 30 made of a ferromagnetic material ensures re-looping of the magnetic flux between the end 11 of the fixed core 10 opposite the plate 12 and the latter.

The solenoid valve 1 also comprises an element movable along the axis X under the effect of the magnetic field generated by the coil 20, this mobile element being in the form of a plunger core 40, made of a ferromagnetic material, mobile in translation along the X axis inside the fixed core 10.

The plunger core 40 is inside the fixed core, in the example considered, and the flow controlled by the solenoid valve, which is preferably gaseous, such as for example the fuel vapors takes place in contact with it when the solenoid valve is open .

According to one embodiment of the invention, the plunger core 40 is made of a soft magnetic material, which loses its magnetization when the magnetic field of the coil ceases, as does the fixed core 10.

According to an embodiment of the invention, illustrated in FIG. 2, the plunger core 40 comprises a tubular part 41 and a head 42 formed by an annular return towards the inside. The head 42 is crossed in its center by an orifice for mounting a valve seal 50. The latter has an annular groove in which the return 42 engages and bears against a seat 80 of the conduit 81, which is fixed, visible in FIG. 2, when the solenoid valve is at rest, in order to close the associated duct 81. In the open configuration, the seal 50 is detached from its seat 80.

According to one embodiment of the invention, a non-visible return spring ensures the return of the plunger core 40 to its rest position, of closing the above-mentioned evacuation duct 81, in the absence of electrical supply to the valve.

According to one embodiment of the invention, the fixed core 10 has a thinned zone 70 which makes it possible to concentrate the magnetic induction therein to the point of almost saturating the magnetic material which constitutes this fixed core.

In the context of the invention, the electromechanical device comprises a noise attenuation system 90.

This noise attenuation system 90, illustrated in FIGS. 1 and 2, is formed of a magnet 91, 92, more specifically of a permanent magnet disposed at the junction between the fixed part forming the conduit 81 and the movable element 40 so as to dampen the vibration shock when the duct 81 is closed.

According to one embodiment of the invention, the device comprises at least two permanent magnets 91, 92 arranged on the one hand, for the first magnet 91, at the end of the movable element 40 and on the other hand, for the second magnet 92, at the end of the duct 81, facing one another in order to ensure a magnetic braking force without contact.

In fact, the two magnets will repel each other and will thus create a magnetic braking force which makes it possible to manage docking, that is to say the bringing together of the two parts, mobile and fixed, without shock.

This braking effect makes it possible to limit the shock during contact with the fixed part and the mobile part when the device is closed, and thus suppress parasitic acoustic waves.

According to one embodiment of the invention, the magnets have a dimension adapted to counter the return force of the spring, of the device, while allowing the closure of the device.

According to one embodiment of the invention, the magnets are circular.

According to one embodiment of the invention, the first magnet 91 has a central opening adapted for the passage of the conduit 81.

According to one embodiment of the invention, the second magnet 92 has a central opening adapted for the passage of the valve seal 50.

According to one embodiment of the invention, the magnets are rectangular or square.

According to one embodiment of the invention, the magnets are fixed by any means compatible with the operation of the device.

FIG. 3 illustrates the results obtained with, curve b and without, curve a, noise attenuation system 90. The curve makes it possible to observe better damping with the noise attenuation system 90, which indicates a weaker impact between the fixed part 81 and the mobile part 40, and therefore less noise.

The scope of the present invention is not limited to the details given above and allows embodiments in many other specific forms without departing from the scope of the invention. Therefore, the present embodiments should be considered by way of illustration, and may be modified without however departing from the scope defined by the claims.

Claims (9)

1. Electromechanical device (1) comprising: a coil (20), a fixed part formed by a discharge pipe (81) an element (40) movable in the direction of the fixed part (81) for closing the discharge pipe (81) under the effect of a return force of a spring, characterized in that it comprises a noise attenuation system (90). 2. Electromechanical device according to claim 1, in which the noise attenuation system (90) is formed by at least one permanent magnet (91, 92) disposed at the junction between the fixed part forming the conduit (81 ) and the movable element (40), so as to absorb the vibration shocks when the duct (81) is closed. 3. Device according to one of claims 1 or 2, wherein the noise attenuation system (90) comprises at least two permanent magnets (91, 92) arranged on the one hand, for the first magnet (91), the end of the movable element (40) and on the other hand, for the second magnet (92), at the end of the duct (81), facing each other in order to provide a contactless magnetic braking force. 4. Device according to one of claims 2 or 3, the magnets (91, 92) have a dimension adapted to counter the return force of the spring, of the device, while allowing the closure of the device. 5. Device according to one of claims 2 to 4, wherein the magnets (91, 92) are circular. 6. Device according to claim 5 when it depends on claim 3, wherein the first magnet (91) has a central opening adapted for the passage of the conduit (81) and the second magnet (92) has a central opening adapted for the passage of a valve seal (50). 7. Device according to one of claims 2 to 4, wherein the magnets (91, 92) are rectangular or square. 8. Device according to one of claims 1 to 7, the device being a canister purge valve. 9. Use of the device according to one of claims 1 to 7, in a motor vehicle.