FR2821128A1 - Pneumatic distributor has slide valve with actuating section of greater diameter at one end - Google Patents

Abstract

The distributor (1), comprising a housing (3) with a bore (2) containing a slide valve (4) controlling a pressure fluid flow between its inlet and outlet connections (10 - 14), has one end (5) of the slide valve made with an actuating section (15) of greater diameter. One face (9) of the actuating section is designed to receive the control pressure needed to switch the distributor, while its opposite face receives the effort of a return spring (17) set in an annular cavity in the housing wall.

Description

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 The invention relates to a pneumatic distributor comprising, slidably disposed in a through bore of a body, a longitudinal slide which controls a flow of pressure fluid in the body, from an inlet fitting to fittings of use or use fittings to return fittings depending on its axial position in the body, which defines with the body and its ends respectively a pressure chamber, and which on at least one of its effective surfaces directed towards a pressure chamber, can be supplied by a control pressure to switch the dispenser against a force of a return device, acting on the longitudinal drawer.

 According to document DE 44 21 357 A1, the overall content of which we will refer here, there is known a pneumatic distributor produced in the form of a 5/2 distributor (5 orifices, 2 positions) monostable, with primary control. The dispenser comprises a dispenser body in which a through bore receives a longitudinal drawer which is sealed and slidingly guided. In the distributor bore are formed, by flares in the form of annular chambers, five chambers of which the one located in the center serves as an inlet chamber on either side of which there is a use chamber. On the side of each of the utilization chambers, distant from the arrival chamber, is connected a return chamber.

These chambers are correspondingly connected to an inlet connection, a first and respectively a second use connection as well as a first and respectively a second return connection, which all exit downward into the distributor body.

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 On a front surface of the distributor body is attached a piston housing inside which is arranged an actuating piston for the longitudinal slide. The piston housing is also closed by an intermediate plate to which is fixed a 3/2 solenoid valve used for primary control.

 The actuating piston is produced with a diameter much larger than the outside diameter of the longitudinal drawer, the longitudinal drawer being provided on its side, namely its end, remote from the actuating piston, with a return piston, the outer diameter corresponds to the outer diameter of the longitudinal drawer, so that the return piston and the actuating piston together form a differential piston with the help of which it is possible to move the longitudinal drawer.

 To actuate the distributor, the coil of the solenoid valve is excited, which reverses the primary control valve and its pressure connection is connected to a control connection. On this occasion, a connection to a drain connection is interrupted, and a pressure derived from the inlet connection is established, via a control line and the solenoid valve open, in a first pressure chamber. from the distributor where it acts on the actuating piston. The force exerted on the actuating piston, namely the pressure acting on the actuating piston, moves the longitudinal slide from a rest position to a working position, because of its larger surface subjected to pressure, relative to the force of the return piston and to a spring acting on the return piston.

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 The disadvantage of this assembly however resides in the fact that the construction configuration of the distributor with a separate actuating piston for switching the distributor, namely for the displacement of the longitudinal slide, is linked to a large construction footprint, leading to outside dimensions of the dispenser, larger than desirable.

 The object of the invention to develop a pneumatic distributor of the type mentioned in the introduction to overcome the drawbacks mentioned.

 In accordance with the invention, this object is achieved for a pneumatic distributor comprising a longitudinal drawer slidably disposed in a through bore of a body, thanks to the fact that the longitudinal drawer has, at one end, an actuation section of enlarged diameter, on the effective surface of which acts the control pressure for switching the distributor, and which is further provided for controlling the flow of pressure fluid to one of the couplings of the distributor. The advantage of this dispenser lies in the fact that it is produced without a separate actuating piston, which considerably reduces the overall length and width.

 Thanks to the enlarged diameter of the actuating section of the longitudinal drawer, there is advantageously, when the longitudinal drawer is moved into its working position, an excess of force which guarantees reliable maintenance of the longitudinal drawer in its working position, and which is already available when switching the distributor

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 for low switching control pressures.

 Furthermore, the enlarged diameter of the actuating section offers, during a return movement of the longitudinal slide from its working position to its rest position, the advantage of producing, following the establishment of the purge pressure. , the action of a force which assists the return movement of the longitudinal drawer. This advantageously makes it possible to guarantee that the longitudinal slide is moved completely into its rest position, even under unfavorable operating conditions.

 Another advantage offered by the pneumatic distributor according to the invention lies in the fact that during a movement of the longitudinal drawer, it is not necessary to exchange air with the environment, which allows to guarantee without any problem the function of the dispenser, even in an environment whose air is contaminated for example by dust particles or other substances, which by penetrating inside the dispenser could hinder its mode of operation.

 According to a preferred configuration of the invention, the return device comprises a return spring which is supported with one of its ends, on the longitudinal slide in the region of the actuating section thereof, and with its other end, on the body. The return spring is advantageously disposed in an annular space delimited by the body and the longitudinal drawer. Furthermore, the through bore has an enlarged diameter in the area of the return spring and the actuating section. In the area of the actuation section, between the longitudinal slide and the body, a seal is provided

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 sealing, which is arranged in an annular groove of the longitudinal drawer. Furthermore, between the body and the longitudinal drawer are formed, by annular protrusions of the longitudinal drawer, several separate chambers, which are provided in such a way along the axial extent of the longitudinal drawer, that the chambers can, respectively from a switching position of the longitudinal drawer, be brought at least partially into overlap with at least one of the fittings. In addition, the chambers are made watertight with respect to each other, each time by another respective seal placed in the area of the annular protrusions of the longitudinal drawer, between them and an inner wall of the body, of in such a way that it is possible to hinder an exchange of pressure fluid between two chambers arranged side by side.

 An exemplary embodiment of a pneumatic distributor according to the invention is shown in the accompanying drawing, and will be explained in more detail in the description which follows.

 The single figure of the appended drawing shows in longitudinal section, a schematic representation of a pneumatic distributor according to the invention, comprising a longitudinal drawer arranged in a sliding and sealed manner in a body.

 In the figure is shown a pneumatic distributor 1 comprising a longitudinal slide 4 mounted to slide in a through bore 2 of a body 3.

In the through bore or the drawer bore 2, open axially, distributed along the length of the drawer bore 2, an inlet connector 10 placed

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 approximately centrally, on either side of it, a use fitting 11 and respectively 12, and on the side thereof, directed outwards, a return fitting 13 and respectively 14. The drawer bore 2 is axially delimited by a pressure chamber 7 and respectively 8, the longitudinal drawer 4 being close, by its first end 5, to the pressure chamber 7, and being close, by its opposite end 6, to the pressure chamber 8 located at the opposite end of the drawer bore 2.

 For the switching of the distributor 1, the pressure chamber 7 is supplied by the control pressure, which produces the bias by force, of the longitudinal slide 4, via its effective surface 9 directed towards the pressure chamber 7 On this occasion, the longitudinal slide 4 is moved in the direction of the pressure chamber 8 in such a way that a flow of pressure fluid is conducted in the body 3, from the inlet fitting 10 to the use fittings. 11,12, or from the use fittings 11,12 to the return fittings 13,14.

 At the first end 5 of the longitudinal drawer 4, this comprises an actuating section 15 having an enlarged diameter relative to the diameter of the remaining part of the longitudinal drawer 4. The effective surface 9 directed towards the pressure chamber 7 is of a corresponding magnitude. The actuating section 15 is moreover provided for controlling the flow of pressure fluid from the use fitting 11 to the return fitting 13 of the distributor 1.

 The control pressure, which for switching the longitudinal slide 4, is applied to

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 the effective surface 9, acts against a force of a return device 16, which acts on the longitudinal slide 4, and which comprises a return spring 17 acting with one of its ends, on a recess of the actuating section 15 of the longitudinal drawer 4, and bearing with its other end, on a shoulder 18 of the body 3. The return spring 17 is thus disposed in an annular space 19 delimited by the body 3 and the longitudinal drawer 4.

 In the pressure-free state of the distributor 1, the return spring 17 produces a defined initial position of the longitudinal drawer 4, in which it rests with the effective surface 9 of the end 5, on the body wall of the pressure chamber 7. During a new supply of pressure to the distributor 1, the longitudinal slide 4 is moved in the axial direction of the distributor 1, from its rest position, namely its first extreme position in the body 3, in a working position, at most up to its second extreme position on the body wall of the pressure chamber 8, facing the effective surface 20 of the second end 6 of the longitudinal drawer 4.

 Due to the configuration of the longitudinal slide 4, with an enlarged diameter in the region of the actuating section 15, the through bore 2 has, in the region of the return spring 17 and the actuating section 15, a larger diameter. large relative to the remaining area of the longitudinal drawer 4, in order to receive the actuating section 15.

 The diameter of the actuating section 15, enlarged with respect to the diameter and the effective surface 20 of the end 6 of the longitudinal slide 4, makes it possible to

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 guarantee that, in the event of a stress on the effective surface 9 of the longitudinal drawer 4, on the longitudinal drawer 4 acts a resultant force which moves the longitudinal drawer 4 from its rest position to its working position, and overcomes the force elastic of the return spring 17 acting against this direction of movement.

 In addition, the longitudinal slide 4 can be securely held in its working position, due to the larger diameter of the actuating section 15, compared to the smaller diameter at the end 6 of the longitudinal slide 4, and of the resulting relationship between the effective surfaces and the corresponding forces.

 To seal the first pressure chamber 7 relative to the annular chamber 19, an annular seal 22 is provided in an annular groove 21 of the longitudinal slide 4, namely in the actuating section 15. , which, with its internal side, rests on the longitudinal slide 4, and with its external side, is in sealed contact with an internal wall 23 of the body 3.

 Between the body 3 and the longitudinal drawer 4, are formed, by several annular protrusions 24A, 24B, 24C, 24D of the longitudinal drawer 4, separate chambers 25A, 25B, 25C, which are arranged in such a way along the extent axial of the longitudinal drawer 4, that they can, respectively as a function of a switching position of the longitudinal drawer 4, be brought at least partially into overlap with at least one of the connections 10, 11, 12, 13,14. This establishes or hinders, in a manner known per se, in particular as described in document DE 44

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 21 357 A1, the connections described above, between the inlet connection 10 and the neighboring use connection 11, 12, or respectively the connections between the use connections 11, 12 and the return connections 13, 14 respectively neighboring .

 To prevent an undesired exchange of pressure fluid, between the fittings 10, 11, 12, 13, 14, that is to say when they are not connected via the chambers 25A or 25C depending on the position of the drawer longitudinal 4, there is provided in the area of the annular protrusions 24A, 24B, 24C, 24D and in the area of the end 6 of the longitudinal drawer 4, each time another respective seal 26A to 26E. in the case of the support of the respective seals 26A to 26E on the inner wall 23 of the body, the chambers 25A, 25B, 25C and another chamber 25D, which is formed by an annular recess on the inner wall 23 of the body between the longitudinal drawer 4 and the body 3, are reciprocally sealed with respect to each other.

 The chambers 25A, 25B, 25C are chambers relating to the longitudinal drawer and are therefore movable relative to the body 3.

 The chambers 19 and 25D are in a fixed position relative to the body 3, and associated with the fittings 13 and 14.

 Depending on the position of the longitudinal slide 4, in the rest position, the connector 13 is connected to the connector 11 via the chambers 19,25A, and the connector 10 is connected to the connector 12 via the chambers 25B, 25C . In the actuated position of the longitudinal drawer 4, the connector 11 is

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 connected to the connector 10 through the chambers 25A, 25B, and the connector 12 is connected to the connector 14 through the chambers 25C, 25D.

 The position shown in the sectional view of the figure is a central position, that the longitudinal slide 4 passes without maintenance during its movement from its rest position to its actuated position and vice versa.

Claims (8)

CLAIMS.  1. Pneumatic distributor (1) comprising, slidably disposed in a through bore (2) of a body (3), a longitudinal slide (4) which controls a flow of pressure fluid in the body (3) of an inlet fitting (10) to use fittings (11, 12) or else use fittings (11,12) to return fittings (13, 14) depending on its axial position in the body (3), which defines with the body (3) and its ends (5,6) respectively a pressure chamber (7,8), and which on at least one of its effective surfaces (9,20) directed towards a pressure chamber (7,8), can be supplied by a control pressure to switch the distributor (1) against a force of a return device (16), acting on the longitudinal slide (4 ), characterized in that the longitudinal slide (4) has, at one end (5), an actuating section (15) of enlarged diameter, on the effective surface (9) of which the pressure acts control for switching the distributor (1), and which is further provided for controlling the flow of pressure fluid to one of the connections (13) of the distributor (1).  2. Dispenser according to claim 1, characterized in that the return device (16) comprises a return spring (17) which is supported with one of its ends, on the longitudinal slide (4) in the area of actuation section (15) thereof, and with its other end, on the body (3).  3. Dispenser according to claim 2, characterized in that the return spring (17) is arranged in an annular space (19) delimited by the <Desc / Clms Page number 12>  body (3) and the longitudinal drawer (4).  4. Distributor according to claim 2 or 3, characterized in that the through bore (2) has an enlarged diameter in the region of the return spring (17) and the actuating section (15).  5. Distributor according to one of claims 1 to 4, characterized in that in the region of the actuating section (15), between the longitudinal slide (4) and the body (3), a seal is provided. (22).  6. Distributor according to claim 5, characterized in that the seal (22) is arranged in an annular groove (21) of the longitudinal drawer (4).  7. Distributor according to one of claims 1 to 6, characterized in that between the body (3) and the longitudinal drawer (4) are formed, by annular protrusions (24A, 24B, 24C, 24D) of the longitudinal drawer (4), several separate chambers (25A, 25B, 25C), which are provided in such a way along the axial extent of the longitudinal drawer (4), that the chambers (25A, 25B, 25C) can, respectively, function from a switching position of the longitudinal slide (4), be brought at least partially into overlap with at least one of the connections (10,11, 12,13, 14).  8. Distributor according to claim 7, characterized in that the chambers (25A, 25B, 25C) are sealed against each other by each time another respective seal (26A to 26D) placed in the area annular protrusions (24A, 24B, 24C, 24D) of the longitudinal drawer, between <Desc / Clms Page number 13>  these and an inner wall (23) of the body, so that it is possible to impede an exchange of pressure fluid between two chambers (19,25A, 25B, 25C, 25D) arranged side by side.