FR2517760A1 - ELECTROVALVE FOR PNEUMATIC INSTALLATIONS, IN PARTICULAR ON VEHICLES - Google Patents

Abstract

ELECTROVALVE FOR PNEUMATIC SYSTEMS. THE MOBILE CORE 14 OF THE SOLENOID HAS COOPERATED WITH A FIRST SET OF SWITCHABLE VALVES 28, 36 WHICH CONTROLS THE COMMUNICATION BETWEEN A CHAMBER DA THE UPPER PART OF A SLEEVE 22 FORMING PISTON AND A PASSAGE 35 COMMUNICATING WITH THE EXTERIOR, AND ANOTHER CHAMBER F PERMANENTLY CONNECTED TO THE SOURCE OF COMPRESSED AIR 30, FORMED IN THE SLEEVE 22 AND WHICH COMMUNICATES WITH A THIRD CHAMBER C PERMANENTLY CONNECTED TO THE USER 46 BY A SECOND SWITCHABLE VALVE 40 CONTROLLING THE COMMUNICATION BETWEEN THE USER AND EITHER THE SOURCE OF COMPRESSED AIR 30, OR THE ATMOSPHERE 44. THE FIRST VALVE 28, 36 CONTROLS THE MOVEMENT OF THE SLEEVE 22 AGAINST THE ACTION OF AN ANTAGONIST SPRING 38 TO ACTUATE THE SECOND SWITCHABLE VALVE 40. APPLICATION TO APPLIANCE CONTROLS AND ACCESSORIES, ESPECIALLY ON VEHICLES, FOR EXAMPLE WINDSCREEN WIPERS, DOORS, GEAR CHANGE SERVOS, DIFFERENTIAL LOCKING, AND THE LIKE.

Description

The present invention relates to a solenoid valve for

  installations or pneumatic equipment of vehicles for the control of

  user devices and devices of different kinds, such as

  windscreen wipers, devices for opening and closing doors,

  , servo-control for shifting or for blocking dif-

  etc. Such solenoid valves normally include a solenol

  or electromagnet which, when powered, controls the opening

  a valve for the admission of compressed air into the organs used

  tors. More particularly, when the user closes the electrical circuit

  of solenoid winding, a magnetic flux is created

  that which attracts the movable core, against the force of a spring, this

  which determines the opening of the intake valve.

  The solenoid is mounted on a body provided with respective connectors

  feed member and for the user device of the compressed air, which are connected to each other via the intake valve which is sealed by sliding and applied against its seat by the

force of the aforementioned spring.

  The known solenoid valves have the disadvantage that it is impossible to

  Several devices and devices with different power requirements, for example, require high airflows for their correct operation for very short periods of time, a condition that small solenoid valves do not have.

  because of the narrow dimensions of the feed passages

  It follows that in vehicles equipped with pneumatic

  It is essential to install solenoid valves of different

  to control user organs with different requirements

  Thus, when an electromagnet with a small battery is used,

  the winding of copper wire is small but the

  magnetic force available for actuation of the core is also

  pick; therefore, the action of the return spring on the core

  must be small in relation to the magnetic force, in order to ensure the opening

  valve during operation Under these conditions, with

  windings of reduced dimensions, the section of the passages for feeding

  The compressed air supply must be reduced to accommodate the air pressure to overcome the opposition of the spring and, thereby, to open the

  valve when it is at rest or inactive.

  With reduced section feed passages it is however impossible to feed users who require large air flows; -2 -

  under these conditions, for this type of users it is necessary to provide for

  for air with a larger section Such passages e-

  on the other hand, the adoption of more powerful springs and consequently

  windings of larger dimensions.

  The object of the present invention is to provide a solenoid valve which

  has feed passages corresponding to the amount of air re-

  for the feeding of relative users, and which uses

  electric winding of reduced dimensions, with the advantage of using only one solenoid valve to control the users who

  part of the pneumatic system. It is therefore obvious that by using

  In the case of a small coil, an appreciable saving is achieved.

  in copper and the cost price of electricity is reduced accordingly.

valve.

  Finally, the solenoid valve according to the present invention, equally

  solenoid winding, allows to control users who e-

  within specified limits different amounts of supply air. The solenoid valve according to the present invention, whose armature actuates the pressurized air intake valve intended for the user, is characterized in that it comprises a switchable valve actuated by the electromagnet and which controls 8 the communication of the pneumatic interception means with the source of compressed air or with the exhaust,

  to provide power to the user.

  According to a preferred embodiment of the solenoid valve according to the present invention, the pneumatic interception means comprise a piston-shaped sleeve subjected to the bias of a spring, which

  maintains a switchable double damper that can be actuated against ac-

  opposing elastic means and whose sealed seats are

  formed partly on said sleeve and for the rest on the body of the elec-

  trovalve, so as to delimit between these parts of the opposite chambers connected to the user and the atmosphere, and the other to the pressure source and the atmosphere through the corresponding switchable valves. Other features of the invention will emerge during the

  reading of the description which follows and refers to the attached drawing of which

  Figure shows an illustration, not a limitation, in terms of

  axial way, a preferred embodiment of the solenoid valve according to the invention.

vention.

  In this figure, the solenoid in A has been designated, which can be

  The solenoid A comprises a winding 10 whose ends terminate at terminals with an electromagnet connected in service (and in the manner to be described hereinafter) to the interception group B. More precisely lamellae 12 connected to the electrical installation so as to generate a sufficient magnetic flux to move the mobile core 14 in translation and from the bottom up towards the

  fixed core 16 against the counter-resistance of a spring 18 -

  The interception group B consists of a metal body

  20 which slidably holds a sleeve 22 forming a piston and provided with a peripheral groove 24, which delimits in this body opposite pneumatic chambers C and D. The sleeve 22 integrally surrounds a pierced disc 25 which ends

  by an appendix also pierced 26 whose upper end bears

  be a valve 28 subjected to the solicitation of a spring and which slides

  in a housing formed coaxially in the lower part of the core 14.

  The sleeve 22 defines together with the disc 25 a receiving chamber F permanently connected by the groove 24 to a threaded connection 30 which terminates a source of compressed air (not shown) The receiving chamber F is connected to the upper chamber D by the intermediate of the hermetic valve

  28 housed in the lower part of the movable core or armature 14 of the

No. I of A.

  This core 14 has one or more longitudinal holes 32 which re-

  Between them, the chamber D and another chamber G, which in turn can be connected by a longitudinal hole 34 pierced in the fixed core 16, to the surrounding atmosphere via an upper connector 35.

  34 ends at its lower end by an annular protrusion of

  with another valve 36 also subjected to the request

  tion of a spring housed in a cavity of the movable core 14.

  Thanks to this arrangement, the valves 28 and 36 constitute a sou-

  switchable poppet which controls the communication from the chamber D, on the one hand with the receiving chamber F and on the other hand, through the through holes 32, with the chamber G, which is connected in turn by

  the hole 34 and the connection 35 to the outside atmosphere.

  The sleeve 22 slides tightly in the bore of the body 20.

  the resilient resistance of a spring 38 which holds the disk pierced against the valve 28 and receives below the aforementioned disk 25 another switchable valve 40 biased by a spring 42 against a seat formed by the sleeve in order to intercept the communication between rooms F and C.

  When the sleeve 22 moves downwards, the valve 40 carries airtight

  -4- against the edge of the internal cylindrical part of a tubular end

  44 concentric to this sleeve 22 and screwed into the body 20 so as to re-

  connect the outside atmosphere to room C This room C is connected to

  permanently, via a connector 46, to the user device or device (not shown) that must be actuated pneumatically. From what precedes, it is clear that if the solenoid valve

  is at rest, that is to say when his organs occupy the position which

  the drawing, rooms C, D and G are connected to the atmosphere, the first

  first C through the tubular end 44 and the other two D and G through the

  through passages 32, 34 and fitting 35 It follows that the supply

  of the user (via the connector 46) is cut by the switchable valve 40.

  The group formed by the sleeve 22, the disc 25 and the check valve

  40 is a piston on the two opposite sides of which acts the compressed air passing through the connector 30 and whose pressure maintains the piston substantially in balance, this piston remaining in practice subjected to the action

  springs 18 and 38, the latter being preponderant compared to the first

mier.

  When the winding 10 of the electromagnet A is fed with the

  As a result of the excitation excitation, the movable core 14 of the electromagnet is attracted upwards, that is to say towards the fixed core 16, against the counterforce of the spring 18. This movement actuates the valves 28 and 36, the first of which establishes the communication between chambers F and D, while the second

  intercepts the communication between this room D and the outside atmosphere

  The compressed air present in chamber F thus reaches the chamber

  D and exerts a pneumatic thrust on the piston 22.

  overcoming the resistance of the spring 38, is moved downwards by the pressure

  sion and causes in its movement the switchable valve 40 which on the one hand closes the communication with the atmosphere and on the other hand connects the

  chamber F to chamber C to introduce compressed air into the

  cord 46, that is to say in the apparatus or user organ -

  When the solenoid A is de-energized, the force of the spring 18 returns the movable core 14 to its initial position, which cuts off the power supply.

  compressed air and restores the communication between chamber D and the atmosphere.

  phère through the passages 32 and 34 Simultaneously, the piston 22 is -

  returned to its initial position by the expansion of the spring 38 which is no longer thwarted by the pressure of the air that was previously present in

  the chamber D Consequently, the piston 22, dragging with it the key

  switchable pet 40, interrupts the communication between the connectors 30 and

  46 and connects the chamber C and the organs or devices users to the

251 7760

  phere. This thus confirms the goals that the present invention has set itself to control a relatively large section of passage for

  compressed air, when a solenoid A having

  limited electric currents that correspond to those of a conventional solenoid valve whose section of the passage of light is substantially reduced

  and corresponds substantially to that controlled by the valve 28 of the drawing.

  Such a passage light could not allow fast feeding

  number of users because of its reduced, improper

  pre-fast flow of high air flow as required by some organs or devices users -On the other hand, the increase of this light passage requires the use of high power electromagnets to prevent pressure air that acts on the check valve can

  either open or close this valve incompletely, even when the elec-

  trovalve is at rest In contrast, the solenoid valve following the present in-

  vention achieves the desired purpose since a light is

  reduced for the command, and passages of sufficient section for the

  feeding of any user.

  However, it is understood that various modifications and variations may be made to the solenoid valve described and shown here, depending on the use for which it is intended, and without departing from the

basic principles of the invention.

6 -

Claims (4)

R E V E N D I C A T I 0 N S CLAIMS   1 Solenoid valve for pneumatic installations or equipment, no.   particularly for equipment installed in vehicles, in which   a solenoid or control electromagnet actuates a valve or a key   f inlet of the compressed air into the device or user device, this solenoid valve being characterized in that it comprises a set of switchable valves (28, -36) actuated by the electromagnet (A) and which control the communication between pneumatic interception means   (22, 40) and either with the source of compressed air (30) or with the exhaust   (35) to provide power to the user (46).   2 Solenoid valve according to Claim 1, characterized in that the   switchable valves (28, 36) are subjected to the biasing of springs and   incorporated in the armature (14) of the solenoid or the like (A) of   to control the communication between a chamber (D) in which a piston (22) subjected to the loading of a spring   (38) and on the other hand either the atmosphere (35) or the source of compressed air   me (30), this piston containing in turn a switchable valve (40)   by a spring and which controls the communication between the use   the user (46) and on the other hand is the atmosphere (44) or the source of air tablet (30).   3 Solenoid valve according to any one of Claims 1 and 2,   characterized in that it comprises a sleeve-shaped piston (22) slidably mounted in a bore of the perforated body (20) of the solenoid valve and provided at its ends with sealed seats for the switchable valves (28, 40) carried by the armature (14) of the solenoid and by said sleeve (22), while the spring (38) urges this sleeve towards its position o the aforementioned seat tightly against the switchable valve (28) worn   by the armature (14) of the solenoid.   4 Solenoid valve according to any one of Claims 1 to 3,   characterized in that it comprises a tubular nozzle (44) housed in the perforated body (20) of the solenoid valve and provided at one of its ends with one of the sealed seats provided for the switchable valve (40) carried by the   sleeve (22) which slides in the bore of said body, the latter comprising   in addition to fittings (30) for compressed air and for the user (46).   Solenoid valve according to one of Claims 1 to 4,   characterized in that the movable core (14) has at its ends respective interception valves (28, 36) subjected to the biasing of springs and which control the communication between the chamber (D) containing the sliding sleeve (22) and the compressed air source (30), on one side, and the user (46) on the other side, while the ends of said core are interconnected by at least one hole (32) which connects said chamber (D) to the atmosphere (35).