FR3069289A1 - MULTI-DOSAGE HYDRAULIC PUMP - Google Patents

Abstract

The invention relates to a multi-metering hydraulic pump comprising: - a motor, - at least one eccentric (108) intended to be rotated by the motor, - at least two pistons (101, 102) each connected to the eccentric . According to the invention, the pump comprises at least two half-links (114, 115) whose closed ends (114a, 115a) are articulated on one of the pistons respectively and whose open ends (114b, 115b) are each connected to the eccentric.

Description

TECHNOLOGICAL BACKGROUND OF THE INVENTION

A hydraulic metering pump allows precise injection of small quantities of fluids.

Such a pump usually comprises a motor driving, via- a mechanical transmission system, a piston in translation · the reciprocating movement of the piston in the pump body allows, either directly or via a membrane , pumping the fluid.

The transmission system thus fulfills two functions. main: the first is to allow the transmission of the mechanical torque from the engine to the piston and the second is to adjust the stroke of the piston in order to control the amount of fluid injected by the pump.

Such a pump therefore proves to be relatively complex in structure.

In order to optimize the cost and size of the hydraulic dosing pumps used, the manufacturers have developed hydraulic dosing pumps making it possible to actuate several pistons by means of a single motor.

So-called "duplex" pumps are thus known in associated with each connected, which the motor is transmitted in mechanical fashion, thus a double metering pump.

Likewise, two to one piston systems are known.

We have

From the "triplex" the pumps in which the engine is associated with so-called three mechanical transmission systems each connected to an associated piston. There is thus a triple dosing pump.

However, with this type of pump, it proves obligatory to associate with each doser of the pump a particular mechanical transmission system.

It has therefore been developed pumps in which at least a part of the mechanical transmission system was common to the different pistons, Thus, common parts allow to participate in the adjustable stroke of the pistons and their actuation by the engine.

These pumps sometimes feel called “boxer” or “fiat twin” in the case of a pump with two membranes.

An operating principle of this type of “fiat twin” pump is visible in FIG. 1 and in FIG. 2. The motor rotates, for example via a reduction gear, a circular eccentric 1 so that the center of rotation R of the eccentric 1 is different from the geometric center G of the eccentric 1. This eccentric 1 is linked to a frame · 2 guided in translation whose opposite ends are respectively associated with one of the pistons 3, 4 of the pump : the off-center rotational movement of the eccentric 1 causes an alternating rectilinear movement of the frame 2 and thus rectilinear movements, alternating if s of the two pistons 3, 4. Thus, when one of the pistons 3 (respectively 4) is in retracted position, the other of the pistons 4 (respectively 3) 20 is in the extended position.

In this way with the same engine and a single transmission system, it is possible to operate two pistons and therefore two metering units in the same pump.

This type of pump can of course be multiplexed so that one can thus find pumps with a duplex configuration (one motor, two transmission mechanisms and four dosers) or a triplex configuration (one motor, three transmission mechanisms and six dispensers').

A major drawback of this type of pump is the risk of seizure and / or significant wear of the pistons and of the frame, in particular due to repeated contacts: with significant efforts between the pistons and the frame.

In order to limit this drawback, the pistons should therefore be as aligned as possible in order to

3 · make sure that the contacts between the frame and the pistons are made correctly.

Pistons; must therefore be manufactured with precision.

In addition, the frame must be able to pull as well as push the pistons during the different successive phases of suction and delivery of the metering units.

This therefore involves contact of the end of the SUE piston with two opposite sides of the frame and therefore again as perfect a parallelism as possible between the two corresponding faces of each end of the piston.

This type of pump therefore proves to be delicate and costly to build.

OBJECT OF THE INVENTION

One aim of the invention is therefore to propose a multi-metering pump of simplified construction.

BRIEF DESCRIPTION OF THE INVENTION

In order to achieve this goal, a multi-metering hydraulic pump is proposed comprising:

- a motor; at least; an eccentric intended to be driven in rotation by the motor, at least two pistons each connected to the eccentric.

According to the invention, the pump comprises at least two half-links; with closed ends; are articulated respectively on one of the pistons and whose open ends are each connected to the eccentric.

Thus, to drive themselves into service, the eccentric allows the two half connecting rods *, which go straight alternately, to cause two pistons directly in motion.

movements

The invention provides; therefore; a simplified multi-dosing pump.

In particular, the invention makes it possible to dispense with a dedicated eccentric frame requiring great precision in particular - in the alignment of the pistons, the invention - using half-connecting rods for the translation drive of the two pistons either articulated parts and simplified construction.

By "multi-metering" pump is meant in the sense of the present application that the pump is shaped to allow adjustment of the piston stroke. This makes it possible to regulate a quantity of fluid injected: by the pistons of the pump (either directly or by means of a membrane).

In particular, the pump includes an insert associated with each second end, each half-rod being mounted on the eccentric at its second end by the intermediary of said insert.

In particular, each insert has a greater height than that of the second associated end.

In particular, the height of each insert is identical to that of the eccentric.

Particularly identical length to that associated.

Particularly self-lubricating material.

each insert has one of the second end the inserts are- in a

In particular, each second end is shaped so as to draw between a quarter of a circle and a semicircle.

In particular, the connecting rods are made of cast iron or steel.

In particular, the motor rotates an output shaft on which the eccentric is mounted, a portion of the output shaft on which the eccentric is mounted being rectangular and the eccentric correspondingly comprising a hole re and an gui a ire form :.

In particular, the pump includes at least one flange for retaining the eccentric half-rods.

Other characteristics and advantages of the invention will emerge on reading the following description of a particular non-limiting embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The: Figures 1 and 2 have already been described and relate to a pump of the prior art.

Furthermore, the invention will be better understood in the light of the description which follows with reference to: figures: attached drawings of which:

FIG. 3 is a perspective view of a part of the pump according to a particular embodiment of the invention, partially exploded,

- the figure 4 is a view sectional front of the part of the pump illustrated: at the figure 3, not exploded, - the. figure 5 is a view: in axial section of the part illustrated pump in the figure 4 - the figure 6 is a view enlarged by one portion of the figure 5 - the figure 7 is a view sectional On top of the pump according to fashion of accomplishment particular of

'invention,

- Figure 8 is a sectional view: partial side of the pump according to the particular embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to Figures 3 to 8, the hydraulic pump 100 according to the particular embodiment described is a double-metering pump.

The pump: 100 thus comprises here a motor 200 connected

pistons' 101, 102 associated respectively

of the pump 100. The pump 100 here comprises two dosers and two membranes (not visible here). The downstream parts of a metered pump, following the pistons, being well known, they will not be further detailed here.

We will now focus on the connection between the engine 200 and the pistons 101, 102.

The motor 200 drives the rotation of an output shaft 103 here through at least one reduction stage.

In particular, the reduction stage is a worm / wheel assembly. Typically the motor 200 rotates a worm · worm 201, itself associated · with a wheel 202, the motor 200 and the worm screw 201 being arranged so that the worm screw 201 extends ortbogonally to the 'output shaft 103. On the other hand, the wheel 202 is arranged so; to be concentric with an end part · -107 of the output shaft 103.

The wheel 202 is integral in rotation with a cylindrical guide 204, for example by means of a flange 203, cylindrical guide 204 which is arranged concentrically with the end part 107 of the output shaft · 103 ..

The cylindrical guide 204 is itself integral in rotation with said end part 107, typically by means of at least one key 205 arranged between the cylindrical guide 204 and the end part 107.

In this way, the rotary torque of the motor 200 is transmitted to the worm 201 which itself rotates the wheel 202. The wheel 202 in turn rotates the output shaft 103 via the guide cylindrical 204.

With the rubber more visible in FIG. 3, the output shaft 103 comprises the first end part · 107, which is therefore the driven part,, a second end part 104 and a driving part which comprises a first portion 105 and a second portion 106.

The second end portion 104 extends axially along an axis A and is rotatably mounted on a frame of the pump 100.

The driving part is in turn the part of the output shaft: 103 driving in rotation an eccentric 108 of the pump. The driving part comprises a first portion 105 and a second: portion 10 6.

The second ion port 106 'extends longitudinally along an axis B which is parallel but not confused with the axis A.

The first portion 105 extends transversely to the second end portion 104 and to: the second portion 15 106 in order to ensure a radial offset between the second end portion 104 and the second portion 106. The first portion 105 thus extends axially along an axis G which is neither parallel nor perpendicular to the axis A and to the axis B.

2® As for the first end part 107, it extends in the extension of the second portion 106 and is shaped to extend axially along the axis A. Eraser already indicated, the wheel 202 and the cylindrical guide 204 are therefore coaxial with said axis A.

The output shaft 103 · comprises two 'rectilinear grooves 109 formed on the leading part. The two grooves 109 thus extend parallel to the axis C on the first portion 105 and the second portion 106. The two grooves 109 are formed symmetrically on the output shaft 103.

The eccentric 108: is here linked in rotation to the driving part by the intermediary of two · shelves or fingers 110 each arranged respectively in one of the grooves 109 of the driving part on the one hand and in a housing 111 eccentric 108 on the other hand.

In order to facilitate the securing in rotation, of the eccentric 108 and the output shaft 103, the first portion 105 and the second portion. 106 are substantially shaped as a rectangular parallelepiped (extending respectively along the axis C and the axis A) and the eccentric 108- has an orifice 112 also shaped as a rectangular parallelepiped for mounting the eccentric 10 108 on the output shaft 103 and the interposition of the fingers

110 between the driving part and the eccentric 108.

The eccentric 108 has a substantially c y 1 i n d r ique shape.

The eccentric 108 is for example made of steel.

Thus, the center of rotation of the eccentric 108 is offset · from the geometric center of the eccentric 108. This makes it possible to ensure the alternative movements of translation of the pistons 101, 102 as we will see below.

Furthermore, the pump 100 is shaped so as to provide adjustment of the stroke of the pistons 101, 102 in order to adapt the dosage of each of the metering devices. To this end, the pump 100 includes a regulator of the relative position between the eccentric 108 and the output shaft 103.

Typically, the adjuster comprises a screw 210 extending, along the axis A partly inside the output shaft 103 at at least the second part d. ' end 104, as well as a nut 211 mounted on the screw upstream of the output shaft 103.

A flywheel 212 of the adjuster arranged outside the pump 100 allows an operator to rotate the wash 210, for example by means of pinions 213 of the adjuster, the screw 210 in turn causing a translation of the nut 211 along the axis A. The nut 211 at 35 resting on the output shaft 103 consequently causes the output shaft 103 to translate along the axis A.

In this way, the relative position of the driving part of the output shaft 103 with respect to the eccentric 108 5 can be modified.

Consequently, due to the cooperation of the fingers 110 ′ and the grooves 109 extending transversely, the sliding of the output shaft 103 in the eccentric 108 · causes a change in the distance between the center of rotation of the ′ eccentric 108 and the geometric center of- the eccentric 108 which makes it possible to modify the displacement of the eccentric 108 and therefore the stroke of the pistons 101, 102. It is noted that the cylindrical guide · -204 makes it easier to slide the 'output shaft 15 103 relative to the eccentric 108.

In particular, the pump 100 is arranged so that:

the flow rate of the pump 100 is maximum when the area of the output shaft 103 in contact with the eccentric: 20 108 is the area of the second portion 106 adjoining the first end portion 107, the flow rate of the pump 100 or zero when the area of the output shaft 103 in contact with the eccentric 108 is a substantially central area of the first portion 25 105 ·.

your pump 100 · thus makes it possible to ensure by the same common elements (in particular the output shaft 103 and the eccentric 108 :) just as well 'a transmission of the driving torque between the engine and the pistons 101, 10'2 an adjustment of the stroke of the two pistons 101, 102, adjustment common to the two pistons 101, 102.

In order to connect the two pistons 101, 102 to the eccentric 108, the pump 100 comprises two half-rods 114, 115.

It will be recalled that a connecting rod usually comprises a straight bar extended by two circular closed ends for the articulation of the connecting rod at its two ends.

A half connecting rod therefore comprises an extended rectilinear bar · on the one hand pat a first end 114a, 115a closed 'circular with a corresponding circular orifice and on the other hand by a second end 114b, 115b open. The second open end 114b, 115b is thus shaped in an arc.

In the particular embodiment illustrated, the second end 114b, 115b is shaped so as to draw between a quarter of a circle and a semicircle.

The first end 114a, 115a of each half-link is respectively articulated on one of the two pistons · 101, 102 of the pump 100 and the second end 114b, 115b of each half-link is connected to the eccentric 108.

The half-rods 114, 115 are typically made of cast iron or of steel.

Preferably, each half-rod 114, 115 is mounted articulated on the eccentric 108 at its second end 114b, 115b by means of an insert 116, 117.

This makes it possible to limit the wear of the half-connecting rods 114, 115 by friction with the eccentric 108.

Each insert '116, 117 is' therefore shaped so as to match the shape · in an arc of a circle of the second end 114b, 115b of the associated half-rod ·.

Each insert 116, 117 thus has a length identical to that of the second end · 114b, 115b associated and therefore extends from one edge to the other of the second end 114b, 115b (in the circumferential direction · of the second end). On the other hand, the height of each insert 116, 117 is greater than that of the associated second end 114b, 115b (in the axial direction of the second end). The height of each insert 116, 117 is here substantially identical to that of the eccentric 108.

In this way the surfaces in contact between the inserts 116, 117 and the half-rods 114, 115 on the one hand, and between the inserts 116, 117 and the eccentric 108 on the other hand are relatively large.

This creates a good mechanical transmission between the eccentric 108 and the pistons 101, 102.

It is further noted that the inserted contacts 116, 117 / eccentric 108 · are of the cylindrical type.

This also promotes the creation of a good mechanical transmission between the eccentric 108 and the pistons 101, 102. In particular, this makes it possible to compensate for potential misalignments of the pistons 101, 102.

In order to secure the insert 116, 117 and half connecting rod

114, 115 associated, the insert and the associated deflator-connecting rod, one has a circumferential groove 118 and the other a corresponding circumferential tongue 119. Here, each half-connecting rod has the groove 118 and each associated insert the corresponding tongue 119.

This allows the insert to be properly pressed around the entire circumference of the second associated end.

In particular, fixings 120 (only one of which is referenced here) reinforce the attachment of each insert 116, 117 to the corresponding half-rod 114,

115. Fasteners 120 are for example screws, glue, nails ...

The inserts 116, 117 are typically of a self-lubricating material. The inserts 116, 117 are for example made of bronze.

Furthermore, in order to ensure that the eccentric 108 can just as well push on the half-rods, during the extension phase of the associated piston, as pull on the half-rods during the retraction phase of the piston associated, the pump 100 · comprises at least one · flange 121 for retaining the half-rods 114, '115 at the eccentric 108'.

The pump 100 'thus comprises a first · retaining flange 121 · which is secured to a first main face 5 of the eccentric 108 (normal to axis B).

The first flange 121 has a cover 122 provided with an annular rim · '123'.

The first flange 121 is thus arranged on the eccentric 108 so that the cover 122 extends 10 over the first main face of the eccentric 108 (the cover 122 therefore being drilled to allow passage of the driving part) and that its rim 123 surrounds circularly and externally the cylindrical face of the eccentric 108 as well as the two inserts 116, 117 attached to the eccentric 108.

The first flange 121 thus secures the half-rod 114, 115 (via the inserts 116, 117) and eccentric 108.

Typically, the flange 123 extends over the entire height of the portions of the inserts 116, 117 projecting from the second ends 114 b, 115 b of the half-links 114, 115.

Preferably, the pump 100 comprises a second flange '124 for retaining the half-links 114, 115 at the eccentric 108.

The second flange 124 is thus secured to the second main face of the eccentric 108 · (normal to the axis B).

The second flange 124 also has a cover · 125 provided with an annular rim 126.

The second flange · 124 is thus arranged on

The eccentric 108 so that the cover 125 extends over the second main face of the eccentric 108 (the cover 125 therefore being drilled · to allow the passage of the driving part) and that its flange 126 surrounds circularly and externally the cylindrical face of the eccentric 108 as well as the two inserts 116, 117 attached to the eccentric 108.

The second flange- 124 thus secures half connecting rods

114, 115 (via the inserts 116, 117) and eccentric 108.

Typically, the rim 12 6 ′ extends over the entire height of the portions of the inserts 116, 117 protruding from the second ends 114b, 115b.

The flanges 121, 124 are typically made of steel.

Thus, the eccentric 108, the inserts 116, 117 and the second ends 114b, 115b are capped on either side (in the axial direction) by the two flanges 121, 124- thus vis-à-vis .

This therefore promotes the creation of a good mechanical transmission between the eccentric 108 and the pistons 101, 102.

In particular, the presence of the two flanges 121, 124 vis-à-vis ensures a resumption of pulling force in a substantially symmetrical manner on the two opposite parallel faces of each second end 114 b, 115 b, during a phase of retraction of the corresponding piston. This limits the risk of biasing one of the half-links 114, 115.

In service, the motor rotates the output shaft 103 around the axis A. The eccentric 108 then pivots according to a center of rotation offset · from its center · of geometry causing alternative movements of translation of the two pistons 101, 102 · by means of the connecting rods 114., 115.

It will be noted that the half-connecting rods 114, 115 are articulated on the eccentric 108 ^ via the inserts 116, 117 and not directly.

The pistons 101, 102 are thus successively pulled and pushed and alternately by the eccentric 108 via the inserts 116, 117, the flanges 121,

124 and half connecting rods 114, 115. The two pistons 101, 102 therefore translate along the same axis but alternatively (when one of the pistons retracts along said axis, the other of the pistons extends along the same ' axis and 5 conversely) allowing the operation of the two associated dosers and the activation of the two respective membranes.

The pump 100 which has just been described makes it possible to ensure a constant relative speed between the two half-connecting rods

114, 115 and eccentric 108: a film of fluid can then form between · these different parts. It was even found that a hydrodynamic regime could thus be reached between the eccentric 108 and the two half-connecting rods

114, 115. This ensures good lubrication of said parts · thus limiting the risk of seizure and / or wear of said · parts.

In addition, the pump 100 which has just been described makes it possible to ensure transmission of the movement between the engine and the pistons 101, 102 by contact zones of the cylinder / eccentric cylinder / insert type, The contact contact

1'intermediate many (such as the first flange / insert, the 'contact: first flange / half connecting rod, the second flange / insert contact, the second contact

25:

flange / half-rod ...). This makes it easier to be able to 'accept defects in parallelism of the pistons 101, 102. Furthermore, this also promotes the creation of a good mechanical transmission between the eccentric 108 and the pistons 101, 102'. Indeed, the surfaces in contact, in particular between the inserts 116, 117 and the eccentric 108, prove to be relatively large.

Of course, the invention is not limited to the embodiment described and variants can be made without departing from the scope of the invention as defined by the claims.

Claims (7)

In particular, although here the pump is a pump 35 double metering, the pump can of course be multiplexed so as to have a quadruple metering pump (one motor, two eccentrics and four pistons) or else a six-fold metering pump (one motor, three eccentrics and six pistons). Furthermore, although here the pistons allow the pumping of a fluid by means of membranes, the pistons may, directly allow the pumping of the fluid. Furthermore, although here the two half-connecting rods are connected to the eccentric by means of the two inserts, the two half-connecting rods can be directly mounted on the eccentric. We could have a different number: flanges than what was indicated. For example, only one flange can be used. We can also get rid of flanges by shaping the inserts and / or the second ends appropriately so that the eccentric can pull as well as push each half connecting rod. the shape of the eccentric and that of the output shaft may be different from what has been indicated. In particular, oh could have a cylindrical eccentric orifice and the part of the output shaft, on which the eccentric is mounted, correspondingly shaped. REVENDIGATIQNS 1. Multi-dosing hydraulic pump including: a motor, at least one eccentric (108) intended to be driven in rotation by the motor ·, at least two pistons (101, 102) each connected to one eccentric, the pump being characterized in that it comprises at least two half connecting rods (114, 115), the closed ends (114a, 11: 5 a) of which are articulated on one of the pistons, respectively - the open ends of which (114b, 115b) are each connected to the eccentric. 2. Pump; according to claim 1, wherein the pump comprises an insert (116, 117) associated with each second end (114b, 115b), each half-rod being mounted on the eccentric (108) at its second end by the intermediate of said insert. 3. Pump according to claim 2 :, in which: each: insert (116, 117) has a height greater than that of the second end (114b, 115b) associated. 4. Pump according to claim 3, wherein the height of each insert (116, 117) is identical to that of the eccentric (108). 5. Pump according to one of claims 2 to 4, wherein: each irisert (116 :, 117) has a length identical to that of the second end (114b, 115b) associated. 6. Pump according to one of claims 2 to 5, in which · the inserts (116, 117) are made of a · self-lubricating material. 7. Pump according to one of the preceding claims, in which · each second end (114b, 115b) is 17 'shaped so as to draw between a quarter of a circle and a semicircle.