EP0048673A1 - Vane-stator wall combination for rotary hydraulic devices - Google Patents

Abstract

This invention relates to rotary hydraulic devices of the volumetric or displacement pump type, having a stator and a rotor and vanes axially sliding in the rotor, the stator comprising at least one bottom surface presenting a variable number of recesses therein with ramps and rectilinear zones suited to the operation, said vanes following said bottom surface. In accordance with the invention, the vanes are equipped with an integral or inset base, with end lobes of cylindric shape having a radius of curvature corresponding to that of the milling cutter used for machining the stator. Access to the recesses occurs by means of two ramps corresponding to the lobes of cylindric shape of the vane bases.

Description

The invention relates to rotary hydraulic devices, of the positive displacement pump type, with stator and rotor and axially sliding vanes in the rotor.

In European Patent Application 81400818-1 filed May 22, 1981, the Applicant has described a rotary hydraulic device of the positive displacement pump type with coaxial stator and rotor and with vanes sliding axially in the rotor, the stator comprising at least one bottom surface having, in a variable number, deformations with rectilinear zones suitable for operation, or recesses, said pallets coming to follow said bottom surface, characterized in that said recesses are made on mobile elements of the stator, so that the depth of said recesses can be made variable, hence a variable flow for the device.

According to an advantageous embodiment, the stator S comprises, on the one hand, ramps R and, on the other hand, mobile stator elements M with recess E, ramps and recesses successively making the relay for constant contact with all or part of the front spout of each sliding pallet (Figure 1).

The movable elements M can move in housings L made in the fixed stator part, under the action when stopped and / or during operation, by an external mechanical, hydraulic or magnetic control.

In European patent application 81401018-7, filed on June 24, 1981, the Applicant described a hydrostatic paddle motor with axial sliding in rotor housings and against a continuous surface of a stator base with recess, and comprising an intercommunication circuit between pallets, behind these. The pallets are each housed in a housing formed in a rotor opposite a stator bottom S comprising recesses, one of which E has, relative to an interstitial plane between rotor and stator and relative to a rotor displacement, a ramp R1 deviating geometrically from said plane, a range P parallel to said plane and a ramp R2 geometrically approaching said plane. Each recess E has a fluid inlet clearance LE and a fluid outlet clearance LS (FIG. 2).

The hydraulic motor with axial vanes leads to the production of trapezoidal vanes P, this for a necessity of linear contact between the base of the vanes and the face of the stator in the access ramps to the recesses. The contact generators G are oriented towards the center of rotation, and parallel to one another (Figure 3).

The machining of such a stator is not possible with a cylindrical milling cutter in circumferential movement. The rational process leads to geometric defects and the contact generators are no longer parallel to each other.

The object of the present invention is to alleviate this problem and to facilitate manufacture (pallets, rotor, stator) and, moreover, to improve the resistance of the pallets to wear and impact.

According to the invention, the pallets are equipped with a monobloc or attached base, with end lobes of cylindrical shape with a radius of curvature corresponding to that of the cutter used for machining the stator. Access to the recesses is via two ramps corresponding to the cylindrical lobes of the pallet bases.

In its movement, the pallet is perfectly in contact with the stator, its movement corresponds to that of the cylindrical milling cutter.

The cylindrical lobes of the bases also have the object of absorbing the end-of-travel thrust due to the acceleration of the pallet caused by its descent or its rise in the recess of the stator.

The part of the base, located between the two cylindrical lobes consists of two opposite lips, a flat contact part of these lips and a generatrix of the cylindrical lobes being in the same plane. The purpose of the lips is to cause the sealing and the veneering of the pallet in the flat and active areas of the stator.

The base of the pallet corresponding to the geometry of the stator, it is no longer necessary to produce a trapezoidal pallet body. The parallelepiped shape facilitates the production of pallets and housings in the rotor.

• la figure 1 est une vue en perspective d'un élément de stator conforme à la demande de brevet 81400818-1 ;
• la figure 2 est une vue développée d'un moteur hydrostatique selon un évidement de fond statorique et une phase de fonctionnement conforme à la demande de brevet 81401018-7 ;
• la figure 3 est un schéma représentatif d'une palette trapézoïdale pour moteur hydraulique à palette à coulissement axial ;
• la figure 4 est une vue en perspective montrant une palette selon l'invention en concordance avec des rampes et une plage de fond statorique ;
• la figure 5 est une vue en coupe d'une lèvre de palette selon l'invention ;
• la figure 6 est une vue en coupe partielle représentant le montage de deux lèvres longitudinales de palette selon l'invention ; et
• la figure 7 est une vue en coupe d'une variante de lèvre de palette selon l'invention.

Other characteristics and advantages of the present invention will emerge from the description which follows, given with reference to the appended drawings, in which:

• Figure 1 is a perspective view of a stator element according to patent application 81400818-1;
• Figure 2 is a developed view of a hydrostatic motor according to a stator bottom recess and an operating phase in accordance with patent application 81401018-7;
• FIG. 3 is a diagram representing a trapezoidal pallet for a hydraulic motor with an axial sliding pallet;
• Figure 4 is a perspective view showing a pallet according to the invention in accordance with ramps and a stator bottom range;
• Figure 5 is a sectional view of a pallet lip according to the invention;
• Figure 6 is a partial sectional view showing the mounting of two longitudinal lips of the pallet according to the invention; and
• Figure 7 is a sectional view of a variant pallet lip according to the invention.

In the embodiment shown in FIGS. 4 to 6, a pallet 1 according to the invention, of generally parallelepipedal shape, comprises a base made of material or attached, offering the particularity of presenting, on the one hand, two end lobes 2 cylindrical in shape whose radius of curvature corresponds to that of the milling cutter F used for machining the stator base surface with ramps R and ranges P and, on the other hand, lips lon gitudinal 3 whose sole 3A is capable of bearing on said areas in order to obtain sealing and plating of the pallet. It should be noted that a generator 4 of the cylindrical end lobes 2 is in the plane corresponding to that of the soles 3A.

The lips 3 of the pallet are moreover capable, during the rotor movement, of passing, in whole or in part, in clearances L provided between pairs of ramps R1 or R2.

The lips 3 are preferably made of a material having its own elasticity which is used to improve their contact against the active areas of the bottom stator surface. This material can, of course, be natural or synthetic.

Each lip has a compensating portion 3B exposed to the pressure of the fluid so that this pressure is exerted substantially perpendicular to the stator surface, thus improving the application of the pallet against the stator surface.

In the embodiment shown more particularly in Figures 5 and 6, each lip is hollowed out with a groove 5 allowing it to be mounted on a corresponding rib 6 of the pallet and has a flange 7 allowing it to be immobilized against the pallet using a plate 8 (Figure 6) and threaded studs 9 of which only one. is shown schematically in Figure 6.

In the variant of Figure 7, each lip 3 has a dovetail rib 10 slid into a corresponding groove 11 provided in the pallet. This mounting dispenses with the fixing plate 8 with threaded stud 9.

It is understood that the present invention has only been described and shown as a preferred example and that it is possible to provide equivalences in its constituent elements without, however, departing from the scope of said invention which is defined. in the claims which follow.

Claims (8)

1. - Pallet-stator bottom assembly for rotary hydraulic devices of the positive displacement pump type with coaxial stator and rotor and with vanes sliding axially in the rotor, the stator comprising at least one bottom surface having, in a variable number, recesses with ramps and rectilinear zones suitable for operation, said pallets following said bottom surface, characterized in that the pallet (1) comprises a base (2) of cylindrical contact with the ramps (R1, R2) of the stator bottom, according to a radius of curvature corresponding to that of the cutter used for machining the stator bottom, and lips (3) for sealing and plating against the straight areas of the stator bottom. 2. - Pallet-stator bottom assembly according to claim 1, characterized in that the pallet (1) is parallelepiped. 3. - pallet-stator base assembly according to any one of claims 1 and 2, characterized in that the pallet comprises two opposite lips for sealing and plating (3), a flat part (3A) for contact of these lips and a generator (4) of cylindrical contact of the base being in the same plane. 4. - pallet-stator bottom assembly according to any one of claims 1 to 3, characterized in that each ramp shows a central clearance (L) to thus form a part of two similar ramps, said sealing lips and cladding (3) of the pallet finding a passage in said central clearance during the rotor movement, the cylindrical contact of the base with the ramps then being ensured by two end lobes of the base (2) which improve the resistance of the wear and shock pallets. 5. - pallet-stator bottom assembly according to any one of claims 1 to 4, characterized in that each lip (3) has a compensating portion (3B) exposed to the pressure of the fluid so that this pressure can be exerted substantially perpendicular to the stator surface. 6. - Pallet-stator bottom assembly according to any one of claims 1 to 5, characterized in that the lips (3) are made of a material having its own elasticity. 7. - pallet-stator bottom assembly according to any one of claims 1 to 6, characterized in that each lip is hollowed out by a groove (5) allowing its mounting on a rib (6) corresponding to the pallet and has a rim (7) allowing it to be immobilized against the pallet using clamping means (8, 9). 8. - Pallet-stator bottom assembly according to any one of claims 1 to 6, characterized in that each lip comprises a dovetail rib (10) slid into a corresponding groove (11) provided in the pallet.

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