FR3042574A1 - HYDRAULIC FLUID DISPENSER UNDER CONTROLLED PRESSURE - Google Patents

Abstract

Dispenser, in particular hydraulic manipulator having a pressure regulator (150) with a bore (121) receiving a pusher (160) subjected to the action of the control member (110) and to return forces (172), a drawer (180) subject to pushing the pusher (160) against the force of a setting spring (188) and a cavity (123) separating the bore (121) from the pusher and that (126) from the drawer (160) , housing the setting spring (188) and communicating with the outlet to the tank (101). The bore (121) delimits a damping chamber (190), filled with liquid whose volume of the chamber is reduced as a function of the return movement of the pusher (160).

Description

Field of the invention

The subject of the present invention is a hydraulic fluid distributor, in particular a hydraulic manipulator having a pressure regulator receiving hydraulic fluid under a high pressure to supply it in a controlled manner to a downstream device at a pressure fixed by the actuation of an organ. for controlling the regulator having a bore receiving a pusher subjected to the action of the control member and to return forces, a drawer subjected to the thrust of the pusher against the force of a setting spring defining the outlet pressure by controlling the communication between the high-pressure liquid inlet and the liquid outlet at the set pressure, an axial cavity separating the bore of the pusher and that of the spool, housing the setting spring and communicating with the outlet to the reservoir .

State of the art

Such pressurized hydraulic fluid distributors are known from document EP 1 556 618 as well as FR 2 009 201, FR 2 376 978, FR 2 507 732 and FR 2 781 846.

Such liquid distributors, used in particular as a hydraulic manipulator controlled either with a lever in the hand or with a pedal for foot control, have the disadvantage in certain operating states, to oscillate the control member when returning the dispenser from its active position to its neutral position.

Such oscillations of the device are not only troublesome for the operator, but tire the device or operate unintentionally one or more pressure regulators, particularly in the case of distributors equipped with locking electromagnetic coils.

These vibrations are all the more troublesome that they can be maintained or amplified by external causes, such as the dynamic movements of the machine equipped with actuators controlled or powered by such a distributor.

Purpose of the invention

The present invention aims to develop a distributor for damping the oscillations or vibrations of the evenings, that is to say the control lever or the foot control to prevent the distributor vibrates or oscillates around its neutral position when released from its active position.

DESCRIPTION AND ADVANTAGES OF THE INVENTION For this purpose, the subject of the present invention is a distributor of the type defined above, characterized in that the pusher delimits with its bore a variable-volume damping chamber filled with hydraulic fluid. , the volume of the chamber being reduced as a function of the return movement of the pusher from its setting position and the damping chamber communicating with the return of hydraulic fluid to the reservoir by at least one throat of the liquid outlet so to slow down the return movement of the regulator.

The dispenser according to the invention has the advantage of damping the movement between the pusher and the body of the dispenser when the pressure reducer is returned to the neutral position. The operation of the dispenser is thus more regular and more comfortable for the operator. It is also quieter since it does not generate vibrations which in addition does not tire the material in and around the dispenser. The vibration-free operation also avoids unnecessarily fatiguing the operator who, by his maneuvers, is obliged to spend innumerable times in the neutral position. The damping device of a pressure regulator in the dispenser also has a safety advantage in preventing the unintentional release of one or more pressure regulators integrated in the same dispenser.

According to another advantageous characteristic, the dispenser has a body housing at least one pressure regulator controlled by the actuating member and having along the axis, the pusher bore continuing through the cavity forming a shoulder and this cavity continuing itself through the drawer bore traversed by the channel coming from the high-pressure source and communicating with the set pressure liquid outlet, the drawer bore receiving the drawer regulating the communication between the inlet channel of high pressure liquid and the outlet to regulate the liquid pressure supplied to the downstream device and the low pressure outlet to the reservoir, the user, the drawer pushed into the neutral position by a setting spring being provided with a control rod through the cavity to come into contact with the pusher.

The dispenser according to the invention with the damped regulator is a particularly simple embodiment since the damping means are integrated in the pusher and use the hydraulic fluid of the dispenser. This embodiment does not complicate the manufacture of the dispenser since it integrates into the shape of the pusher.

According to another advantageous characteristic, the pusher is formed of a lower part of diameter equal to the diameter of the bore and of an upper part of diameter smaller than that of the bore, this upper part being received in a plug housed in the opening of the bore and the damping chamber is delimited by the bore, the upper part of the pusher and the plug. This embodiment of the pusher with a lower portion and an upper portion and the resulting embodiment of the damping chamber allows a particularly simple manufacture and assembly of the dispenser through the plug which defines the damping chamber when the regulator with its pusher are installed in the various bores of the regulator.

According to another advantageous characteristic, the pusher comprises a blind hole opening into its bottom and reaching the upper part as well as at least one transverse opening opening into the free surface of the pusher and provided with a throat.

This embodiment allows a particularly simple communication between the damping chamber and the hydraulic fluid outlet to the reservoir.

According to another advantageous characteristic, the upper portion of the pusher has on its surface not covered by the plug in the slide adjustment position, a filling bore opening into the axial bore to ensure the filling of the damping chamber with hydraulic fluid. . This avoids both cavitation phenomena and also the inclusion of air bubbles in the damping chamber, which would hinder its operation and reduce efficiency.

The uncovered surface of the upper part of the pusher is the one that emerges when the pusher is pressed to its active position and also in its active position. The filling bore which ensures the communication between the damping chamber and the cavity itself connected to the liquid reservoir ensures the filling of this chamber for the damping of the movements of the control member when it is returned to its neutral position.

According to another advantageous characteristic, in the case of a distributor provided with an electromagnetic coil for blocking the position of the control member by blocking the pusher against the electromagnet, the pusher is formed of a lower portion of a diameter equal to the diameter of the bore which receives it and of an upper part of diameter smaller than that of the bore, the pusher being received in the support of the electromagnetic coil of the position lock of the regulator, forming a bore for this upper part and a bore for the lower part, the damping chamber then being delimited by the lower bore in the support and parts of the pusher.

In this embodiment, the support of the attraction and locking electromagnet thus constitutes, from the functional point of view, a part of the distributor body which forms the bores receiving the upper part and the lower part of the pusher of different diameters and thus realizing the depreciation volume.

According to another advantageous characteristic, in the case of such a distributor with electromagnetic blocking, the pusher comprises in its lower part, at least one notch open in the wall of the lower part and opening into the shoulder between the two diameter parts. different from the pusher for communicating the chamber with the cavity when the pusher is in the lower position.

Finally, according to another advantageous characteristic, the orifices of the pusher open into a groove of the upper part of the pusher. These grooves have the advantage of distributing the liquid more easily to the orifices with throttles to regulate as much as possible the arrival of liquid in the orifice or openings and ensuring the damping function eliminating the vibration of the pusher.

In conclusion, the hydraulic fluid dispenser under a controlled or controlled pressure has the advantage of being of particularly simple manufacture, not calling into question the usual manufacture of such dispensers or their installation and simplifying its use for the operator or operator of work while making this distributor more efficient and more comfortable for the operator who controls it.

drawings

The present invention will be described hereinafter in more detail with the aid of exemplary embodiments of dispensers shown in the accompanying drawings in which: FIG. 1 is an axial sectional view of a first embodiment of a dispenser showing on one side a pressure regulator in the active position and on the other side the body of the dispenser without the pusher and the pressure regulator, Figure 2 is a sectional view similar to that of Figure 1 for a second embodiment of a distributor with electromagnetic locking of position, FIG. 3 is a front view of the pusher of the distributor according to the second embodiment, FIGS. 4A and 4B show in partial sectional view the pusher of FIG. its bore according to two pusher driving positions, FIG. 5 shows in its parts 5A, 5B the first embodiment of the distributor in axial section of two regulators of 5A shows the operating position of a pressure regulator, FIG. 5B shows the neutral position of the two pressure regulators, FIG. 6 shows in its parts 6A, 6B an axial sectional view. of the second embodiment with two paired pressure regulators; FIG. 6A shows the active position of the regulators; FIG. 6B shows the neutral position of the regulators. Description of Embodiments of the Invention

By convention, the orientation used in the description for the location of the elements is the orientation of the figures. According to this orientation convention, the terms: high, low, upper, lower, rising, descending and others have meaning only in relation to the orientation of the figures to facilitate and simplify the description.

FIG. 1 shows in its two parts a partial sectional view of a first embodiment of a hydraulic liquid distributor 100 such as a manipulator actuated by a control member 110 in the form of a lever 111 carried by the body of distributor 120, via a hinge 112 and in particular a cardan joint. The control member 110 comprises a spider 113 with fingers for actuating the dispenser by enabling two groups of pressure regulators to be controlled to output regulated pressures to a setting value imposed by the control member 110.

The drawing is limited to the sectional view of a single regulator activated by the thrust exerted by the control member 110 in the direction of the axis XX of the device; the other regulator is shown without the pusher and the drawer to show the structure of the dispenser body 120.

In general, the control member 110 acts by an axial thrust XX either by pivoting a spider pin 113 as in the present example, or by a translation action in the axis XX, for example, by a pedal .

The regulator 150 as shown is in alignment with the axis XX, a pusher 160 housed in a bore 121 continuing with a cavity 123, of reduced section forming a shoulder-ment 122 with the bore 121 and joining another bore 126 of smaller section housing a slide 180, and traversed by a channel 127. The end of the slide 180, cavity side 123 is provided with an axial rod 183, 185 terminated by a head 187 into a housing 165 in the bottom 164 of the pusher; the other end of the slide 180 has an axial bore 182 opening into the drawer bore 126 and the outlet 128. The drawer bore 126 is traversed by a channel 127 connected to the source of high pressure liquid SHP and opening into the axial drilling 182 of the slide 180 connected to the downstream device receiving the hydraulic fluid at the pressure set by the pressure regulator 150. The liquid outlet 128 at the set pressure comprises a connection 129 for the connection of the downstream device (U) not shown.

Thus, as shown in the right-hand part in FIG. 1, the distributor body 120 comprises, in the axis XX of the regulator 150, starting from the side of the control member 110, the bore 121 housing the pusher 160 and communicating with the cavity 123 of reduced section forming the shoulder 122 with the bore 121, this cavity being connected by the bore 124 to the reservoir 101, the drawer bore 126 of reduced section relative to that of the cavity 123 forming a shoulder 125 and receiving the spool, 180 being cut through the channel 127 of high pressure liquid from the source of high pressure liquid (SHP), and the drawer bore 126 continuing through the outlet or a branch 128, 129 of the user (U) of hydraulic fluid at the pressure set by the control member 110.

The pusher 160 has an upper portion 161 of reduced section joining, by a shoulder 162, a lower portion 163 which is at the section of the bore. The upper portion 161 is guided in the bore 135 of a plug 130 closing the top of the bore 121. The upper portion 161 of the pusher protrudes from the plug 130 to receive in abutment, the end of the associated finger of the spider 113 of the control member 110. The bore 121 also receives a cup 170 between the bottom 164 of the pusher and the shoulder 122; this cup 170 is pushed by a return spring 172 housed in the cavity 123 and supported by its other end against the shoulder 125 of the drawer bore 126.

The cup 170 is independent in translation (axis XX) of the bottom 164 of the pusher but when the cup 170 rests against the bottom 164 it is secured in the transverse direction by a connection by the form with the bottom 164 which has a central portion in relief on which engages the hollow 171 of complementary shape of the cup 170.

The spool 180 is formed of a hollow portion with an axial bore 182 opening on the side of the controlled pressure liquid outlet and a rod (183, 185) continuing the top of the spool forming a first shoulder 184 by a first rod segment 183 then a second shoulder 186 with a second rod segment 185, and ending with a head 187 coming into the housing 165 opening from the bottom 164 of the drawer 160.

The rod 183, 185 passes freely through the cup 170 retained on the second segment 185 by a retaining washer 173, between the head 187 and the second shoulder 186.

The rod 183, 185 is surrounded by a setting spring 188 whose upper end rests against the cup (or washer) 170 and the lower end against a washer 189 retained by the first shoulder 184 forming a support. The geometry of the slide 180 and its transverse bore 181 and the travel of the slide are such that in the neutral position, the transverse bore 181 opens into the cavity 123 thus communicating the outlet with the cavity 123 which is at the pressure of the liquid in the tank 101.

In the active position (that is to say in a position different from the neutral position) the slide 180 is depressed more or less so that its transverse bore 181 gradually opens into the channel 127 and thus regulates the passage of the liquid to the fixed pressure, to the output 128 connected to the downstream device. This active position is shown in Figure 1. The detail of the setting of the output pressure is as known and described in the documents of the state of the art.

According to the invention, the pusher 160 forms, in the bore 121, a damping chamber 190 delimited at the top by the plug 130. The difference in diameter between the bore 121 and the upper portion 161 of the pusher leaves a sufficient interval for the sleeve-shaped plug 130 to incorporate an outer annular seal 131 in contact with the bore 121 and an inner seal 132 in contact with the upper portion 161 of the pusher.

The plug 130 is itself blocked by a plate 134 covering the top of the body 120 of the dispenser. In its upper portion 161, the pusher 160 has one or more transverse orifices 191, preferably oriented radially and opening out of the free surface of the pusher and into the axial bore 193 open in the bottom 164 in the housing 165 of the pusher receiving the head 187 of the spool rod 180. This piercing 193 communicates with the cavity 123 through and around the cup 170 centered, by its connection by the shape with the bottom 164 in relief of the pusher so as not to rub against the wall of the bore 121.

The hole or holes 191 have a constriction for braking the passage of liquid from the damping chamber 190 back to the tank 101. There is also an orifice 192 without throttling. The orifices thus form decompression or filling orifices of the chamber.

The hole or holes 191, 192 are distributed over the upper portion 161 of the pusher 160 to be in communication with the damping chamber 190 on the portion of the pusher which defines this chamber, of variable height, between the maximum driving position of the pusher according to Figure 1 and the maximum position of raising the pusher, when the axial height of the chamber 190 is reduced to a minimum.

The surface of the upper part 161 is uncovered under the plug 130 when the pusher 160 is depressed, to put the slide 180 in a setting position of the liquid outlet pressure. The adjustment positions of the slide 180 are those which put the transverse bore 181 more or less in communication with the channel 127 through which the high-pressure liquid arrives.

The maximum driving position is that for which the upper portion 161 is the clearest of the plug.

Conversely, when the pusher 160 is raised to the maximum, its shoulder 162 is close to the plug 130, or even in contact therewith.

To allow the liquid to exit the damping chamber 190 and prevent a blockage by a liquid retainer in the bottom of the chamber, there is provided at least one bore 191 with a constriction 192 at the shoulder 162.

Although the orifices 191 with the constriction are not unidirectional and allow the return of the liquid if the chamber 190 is depressurized by the movement of the pusher, there is provided at the top of the upper portion 161, a bore 192 without throttling to facilitate and possibly accelerate the filling of the chamber 190 when the pusher 160 is depressed to the maximum, that is to say when the drawer (and the pusher) are in the adjustment position and that during the upward movement of the pusher 160, this orifice 192 will be quickly covered in the bore 135 of the plug 130 so that the orifices 191 with their throat 192 play the role of damping by braking the liquid outlet.

Thus, at the raising of the pusher 160, when the regulator is controlled to return to the neutral position, the damping chamber 190, filled with hydraulic fluid gradually discharges this liquid whose output is braked by the constrictions of the orifices 191. The movement of the pusher 160 is thus damped and it does not vibrate when it arrives in neutral position.

Figure 2 is a sectional view of the same type as that of Figure 1, but an alternative hydraulic distributor 200 electromagnetic lock.

The parts of this second embodiment, which are identical or similar to those of the first embodiment, have the same references increased by 100. But all the analogous or identical parts bearing these references will not necessarily be redescribed.

The body 220 of the distributor has a housing 221a receiving in the upper part an electromagnetic coil whose support 240 forms the guide of the pusher 260 leaving on top the place 236 for the plate 266 carried by the pusher and which will be retained by the electromagnet .

In the upper part, the support 240 has an upper bore 241 with a groove for receiving a seal and under this bore, there is a lower bore 242 of larger diameter. In the axis XX, under the housing 221a, the body 220 has a bore 221 in which the flange 243 is engaged at the lower end of the support 240. The bore 221 receives a sliding sleeve 245 supported by a helical spring 246 and constituting an elastic stopper signaling to the control member 210 the end of stroke stroke of the pusher 260.

Under this bore 221 is the cavity 223 connected by the bore 224 to the tank 201 and under the cavity, the drawer bore 226. The drawer 280 has a rod 283, 285 rising in the axis with its head 287 in the housing 265 of the bottom of the pusher 260. The rod passes through, as in the previous example, the cup 270 which rests against the bottom of the pusher 260. This cup 270 also serves as a high support for the calibration spring 288 of which lower end is supported by a washer 289 on the shoulder 284 of the rod.

In this example dispenser 200, the pusher 260 is as before, formed of a lower portion 263 guided in the lower bore 242 of the support 240 and an upper portion 261 of reduced diameter, guided in the upper bore 241 of the support 240.

The support 240 of the electromagnet assimilated here to the body of the distributor, forms with the pusher 260 a damping chamber 290 receiving hydraulic fluid from the cavity 223.

As before, the pusher 260 has one or more orifices 291, in particular radially oriented, and provided with constrictions. These orifices 291 open into the axial bore 293 of the pusher, open towards the cavity 223 connected to the reservoir 201.

The damping chamber 290 functions as that of the previous embodiment. Starting from the active position, when the pusher 260 is returned to the neutral position, the hydraulic liquid arrived in the damping chamber 290 is gradually pushed towards the reservoir 201 through the orifices 291 provided with the constrictions. This passage of the liquid reduces the return speed of the pusher 260 and dampens its movement to the neutral position, avoiding oscillations around the neutral position.

Figure 3 is a front view of the pusher 260 of the second embodiment. This pusher 260 has a peripheral groove 294 at the orifices 291 provided with constrictions. Under the constrictions, in the part which, at the end of the maximum stroke of the pusher 260 is in an active position, there is one or more notches 295 allow the communication between the damping chamber 290 and the cavity 223 filled with hydraulic fluid of so as to ensure that the damping chamber 290 is thus filled with hydraulic fluid which, during the rise of the pusher 260, will ensure the damping of this movement by braking as described above.

FIGS. 4A and 4B show two positions of the pusher 260 in its bores 241, 242 represented here as made in the support 240 but which could also be the body and the plug according to the example of FIG. 1. FIG. 4A represents the position maximum sink. In this position, the two lateral notches 295 below the abutment surface formed by the shoulder 262 between the lower portion 263 of the pusher and its upper portion 261 communicate the cavity 223 with the damping chamber 290 to ensure its filling with hydraulic fluid. FIG. 4B shows the high position of the pusher 260. In this position, the last damping orifice 291 remains in communication with the peripheral groove 294 of this orifice with the damping chamber 290, the height of which is then reduced to the maximum.

Due to the position of the sectional plane of FIGS. 4A, 4B and with reference to FIG. 3, as the lateral notches 295 correspond geometrically to the intersection of a circular section half-cylinder according to the section of the notch 295 and the cylindrical surface of the lower portion 263 of the pusher 260, in a square section, the outline appearing on both sides of Figure 3 and in the section of Figure 4A gives the impression that the pusher 260 n is not in contact with the bore. Now, it is in contact by the segments of its surface which remain between the notches 295, whether they are two or four in number.

FIG. 5A shows in its parts 5A and 5B two characteristic positions of the distributor 100. In FIG. 5A, the control member 110 is actuated to put the left-hand pressure regulator 150G in its extreme position corresponding to the most open large of the through orifice of the slide thus regulating the pressure of the hydraulic fluid supplied to the outlet at the maximum regulating pressure of the regulator.

FIG. 5B shows the neutral position of the distributor 100. In this position, the two drawers 180 of the regulators 150G, 150D are raised. They cut the supply channel 127 to the outlet of the downstream device U so that it no longer receives hydraulic fluid under pressure. The through orifice of the two drawers 180 is then at least partially above the shoulder 125 between the cavity 123 and the drawer bore 126 so that the assembly is placed in communication with the reservoir 101, that is, the pressure of the liquid in the tank 101.

Figure 6 in its parts 6A and 6B shows the two characteristic positions of the blocking electromagnet distributor 200. In Figure 6A the left-hand regulator 250G is in the active position (the drawing is not exact).

FIG. 6B shows the two regulators 250G, 250D in the neutral position, the supply of the downstream device being then cut off, in the neutral the outputs to the downstream device U being placed in communication with the tank 201.

The pairs of regulators 150G, 150D or 250G and 250D operating in opposition make it possible to control for example double-acting cylinders whose supply of the active phase chamber is done with hydraulic fluid under pressure regulated by a regulator while the evacuation of the other chamber of the cylinder is through the other regulator of the same pair, open towards the return to the tank.

NOMENCLATURE OF MAIN ELEMENTS 100 200 Hydraulic fluid distributor 101 201 Tank 110 210 Actuator 111 Lever 112 Articulation 113 Spider 120 220 Valve body 221a Clamp 121 221 Bore 122 222 Shoulder 123 223 Cavity 124 224 Drilling to tank 125 225 Shoulder 126 226 Drawer bore 127 227 Channel 128 228 Outlet 129 229 Fitting 130 Cap 131 Outer seal 132 Inner seal 134 234 Plate 135 Bore 236 Plate location 240 Coil holder 241 Top bore 242 Bottom bore 243 Collet 245 Sliding bushing 246 Spring 150 250 Regulator 160 260 Tappet 161 261 Upper part 162 262 Shoulder 163 263 Lower part 164 264 Bottom 165 265 Axial housing 266 Plate 170 270 Cup 171 271 Hollow 172 272 Return spring 173 273 Retaining washer 180 280 Drawer 181 281 Cross drilling 182 282 Axial drilling 183 283 First stem segment 184,284 First shoulder 185,285 D second stem segment 186 286 Second Shoulder 187 287 Head 188 288 Set spring 189 289 Washer 190 290 Damping chamber 191 291 Orifice with throttle 192 292 Orifice 193 293 Axial bore 294 Perimeter groove 295 Notch

Claims (8)

1 °) hydraulic fluid dispenser, in particular a hydraulic manipulator having a pressure regulator (150) receiving hydraulic fluid under a high pressure to supply it in a controlled manner to a downstream device (U) at a pressure set by the actuation d a control member (110), the regulator having a bore receiving a pusher subjected to the action of the control member and to return forces, a drawer subjected to the thrust of the pusher against the force of a spring setting the output pressure by controlling the communication between the high-pressure liquid inlet, the liquid outlet at the set pressure, and the outlet to the reservoir, an axial cavity separating the bore of the pusher and that of the spool , housing the setting spring and communicating with the outlet to the reservoir, characterized in that the pusher (160, 260) delimits with its bore, a chamber of am damping (190, 290) of variable volume, filled with hydraulic fluid, the volume of the chamber (190, 290) being reduced as a function of the return movement of the pusher (160, 260) from its adjustment position, and the damping chamber (190, 290) communicating with the return of hydraulic fluid to the tank (101) by at least one throat (191) of the liquid outlet so as to slow down the return movement of the regulator. 2) Hydraulic liquid distributor according to claim 1, characterized in that it has a distributor body (120, 220) housing at least one pressure regulator (150, 250) controlled by the actuating member (110). , 210) and having along the axis (XX), a pusher bore (121, 242) continuing through a cavity (123, 223) forming a shoulder (122, 222) and this cavity continuing itself by a spool bore (126, 226) traversed by the channel (127, 227) from the high pressure source (SHP) and communicating with the controlled pressure liquid outlet (128, 228), the spool bore ( 126, 226) receiving the spool (180, 280) controlling the communication between the high-pressure liquid inlet channel (127, 227), the outlet for adjusting the liquid pressure supplied to the downstream device and the low-pressure cavity ( 123, 223) communicating with the reservoir (101, 201) via the channel (124, 224), the spool (180, 280) pushed into position n by a setting spring (188, 288) being provided with a control rod (183, 185, 283, 285) passing through the cavity (123, 223) to contact the pusher (160, 260). 3 °) dispenser according to claim 1, characterized in that the pusher (160) is formed of a lower portion (162) of diameter equal to the diameter of the bore (121) and an upper portion (161) of diameter smaller than that of the bore, this upper portion (161) being received in a plug (130) housed in the opening of the bore (121) and the damping chamber (190) is delimited by the bore (121), the upper portion (161) of the pusher and the plug (130). 4) A dispenser according to claim 1, characterized in that the pusher (160, 260) comprises a blind hole (193, 293) opening into its bottom (164, 264) and reaching the upper part and at least a transverse orifice (191, 291) opening into the free surface and provided with a constriction. 5 °) Dispenser according to claims 1 and 4, characterized in that the upper portion (161) of the pusher (160) has in its surface not covered by the plug (130) in the adjustment position of the slide (180), a drilling filler (192) opening into the axial bore (193) to ensure the filling of the damping chamber (190). 6 °) dispenser according to claim 1, characterized in that the pusher (260) is formed of a lower portion (263) of diameter equal to the diameter of the bore (242) receiving the pusher and an upper portion (242) 261) of smaller diameter than that of the bore (242), - the pusher (260) being received in an electromagnetic position-locking coil holder (240) of the regulator (250), forming a bore (241) for the upper portion (262) and a bore (242) for the lower portion (263), the damping chamber (290) being delimited by the lower bore (242) and the portions (261, 263) of the pusher (260). . 7 °) Dispenser according to claim 6, characterized in that the pusher (260) has in its lower part (263), at least one notch (295) open in the wall of the lower part (263) and opening into the shoulder (262) between the portions (261, 263) for communicating the chamber (290) with the cavity (223) when the pusher (260) is in the down position. 8 °) Dispenser according to claim 1, characterized in that the orifices (291) of the pusher (260) open into a groove (294) of the upper part (261) of the pusher (260).