EP0618366B1 - Volumetric machine with planetary movement - Google Patents

Description

The present invention relates to a volumetric machine with planetary movement.

Machines of this type are in fact known, for example the document DE 42 09 607 describes a volumetric machine comprising a rotor having roughly the shape of a figure eight, that is to say the shape of a Roots pump rotor, which describes a planetary movement inside a stator: the axis of the rotor describes a circle, while it also rotates in opposite directions around its axis. The stator has a profile having three lobes forming three chambers each equipped with an inlet and outlet valve.

However, such machines require a planetary movement drive mechanism with eccentric, bearings .... and therefore lubricated mechanisms.

The object of the present invention is to provide a drive device for machines with planetary movement, without mechanical bearings, and therefore perfectly suitable for dry machines.

est égal au rapport , $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{c}}}}$

et en ce que les N_B bobines électriques de ladite couronne sont alimentées successivement.The subject of the invention is therefore a volumetric machine with planetary movement comprising a cylindrical piston of axis Δ _p , rotary and situated in a cylindrical capsule of axis Δ _c , said piston having, in a plane perpendicular to its axis Δ _p , a section having S _p axes of symmetry, said capsule defining a hollow volume, the section of which, by a plane perpendicular to its axis Δ _c , has S _c axes of symmetry, S _p and S _c differing by one, the axes Δ _p and Δ _c parallel, being separated by a distance E, the piston and the capsule delimiting between them at least three chambers, and the capsule comprising at least one suction inlet and one discharge outlet, characterized in that it further comprises a ferromagnetic pinion of axis Δ _p secured to the piston and comprising N _p teeth, disposed inside a ferromagnetic crown of axis Δ _c and secured to the capsule, said crown being equipped with N _B electric coils arranged radially, in that the ratio $\frac{{\mathit{\text{NOT}}}_{\mathit{\text{p}}}}{{\mathit{\text{NOT}}}_{\mathit{\text{B}}}}$

is equal to the ratio, $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{vs}}}}$

and in that the N _B electric coils of said ring are supplied successively.

According to a preferred embodiment, ensuring operation without any friction, the machine further comprises a wheel with axis Δ _p secured to the piston and with radius R ₁ = S _p E, said wheel being arranged and rolling without sliding in a circular bore d axis Δ _c carried out in a solid surface of said crown, the bore having a radius R ₂ = S _c E.

According to another embodiment, in the case where the eccentricity E is large, corresponding to large dimensions of the piston and of the capsule, the ferromagnetic pinion is surrounded by two rolling rings of radius R ₁ = S _p E and the ferromagnetic crown two raceways with radius R ₂ = S _c E, the radii of the pinion and the crown being such that there is a slight clearance between the pinion and the crown at the level of the generator corresponding at all times to contact with bearing without sliding of said bearing rings on said raceways.

étant différent du rapport , $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{c}}}}$

un léger jeu existant entre les génératrices respectives de l'anneau et de la couronne, les plus proches l'une de l'autre, situées dans le plan contenant les axes Δ_p et Δ_c, et en ce qu'elle comporte en outre une roue d'axe Δ_p solidaire du piston et de rayon R₁ = S_pE, ladite roue étant disposée et roulant sans glissement dans un alésage circulaire d'axe Δ_c effectué dans une portée solidaire de ladite couronne, l'alésage ayant un rayon R₂ = S_cE.The subject of the invention is also a volumetric machine with planetary movement comprising a cylindrical piston of axis Δ _p , rotary and located in a cylindrical capsule of axis Δ _c , said piston having, in a plane perpendicular to its axis Δ _p , a section having S _p axes of symmetry, said capsule defining a hollow volume, the section of which, by a plane perpendicular to its axis Δ _c , has S _c axes of symmetry, S _p and S _c differing by one, the axes Δ _p and Δ _c , parallel, being separated by a distance E, the piston and the capsule delimiting between them at least three chambers, and the capsule comprising at least one suction inlet and one discharge outlet, characterized in that '' it further comprises a ferromagnetic ring of axis Δ _p , of external diameter D ₁ , integral with the piston, disposed at the interior of a ferromagnetic crown of axis Δ _c , of internal diameter D ₂ , and integral with the capsule, said crown being equipped with a plurality N _B of electric coils arranged radially and successively supplied, the ratio $\frac{{\mathit{\text{D}}}_{\text{1}}}{{\mathit{\text{<figure-callout id="2" label="D" filenames="imgf0001.png" state="{{state}}">D</figure-callout>}}}_{\text{2}}}$

being different from the report, $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{vs}}}}$

a slight clearance existing between the respective generatrices of the ring and of the crown, closest to each other, situated in the plane containing the axes Δ _p and Δ _c , and in that it also comprises a wheel of axis Δ _p secured to the piston and of radius R ₁ = S _p E, said wheel being disposed and rolling without sliding in a circular bore of axis Δ _c made in a bearing surface secured to said crown, the bore having a radius R ₂ = S _c E.

According to another characteristic, the machine comprises a magnetic axial stop composed of at least one pair of magnetized rings, linked, one to the fixed part and the other to the mobile part.

The invention will now be described with reference to the accompanying drawing in which:

Figures 1, 2 and 3 show three profiles among the many possible profiles of piston and capsule according to the invention.

Figure 4 shows schematically in section through a plane containing the two axes Δ _p and Δ _c , a machine according to the invention.

FIG. 5 is a section on V-V in FIG. 4.

Figure 6 is a section on VI-VI of Figure 4.

Figure 7 is a variant, according to a view according to that of Figure 6, in which the pinion is replaced by a simple ferromagnetic ring.

FIG. 8 is a variant in a view corresponding to FIG. 4.

FIG. 9 is a section along IX-IX of FIG. 8.

Figure 10 is a section along X-X of Figure 8.

Figures 11, 12 and 13 show three variants of part of Figure 4.

Before describing these figures, in general, the machine comprises a cylindrical piston with axis Δ _p and a cylindrical capsule with axis Δ _c . The axes Δ _p and Δ _c are parallel and distant by a value E.

In this machine, the cylinder defining the shape of the piston has an order of symmetry with respect to its axis Δ _p equal to S _p , that of the capsule an order of symmetry equal to S _c ; S _p and S _c are chosen so that these values differ by one. In addition, the geometry of the piston and of the capsule is chosen so that there is direct correspondence between these elements.

One of the organs, capsule or piston has a profile P ₁ which identifies with a curve uniformly distant from a closed hypertrochoid, having neither double point nor cusp, excluding hypertrochoids degenerated into hypotrochoids, epitrochoids or peritrochoids . The P ₁ profile can also be at zero distance from such a hypertrochoid and therefore identify with it. The definition of hypertrochoids is specified in French patent 2 203 421. The other organ has a profile P ₂ which is the envelope of P ₁ in a relative planetary movement defined by two circles C ₁ and C ₂ of centers and rays respective (0 ₁ , R ₁ ) and (0 ₂ , R ₂ ), these circles C ₁ and C ₂ being respectively integral with the profiles P ₁ and P ₂ and rolling over one another without sliding by internal contact. The centers 0 ₁ and 0 ₂ of the two circles C ₁ and C ₂ are located on the axes Δ _p and Δ _C and the eccentricity of these circles is E = | 0 ₁ 0 ₂ | corresponding to the spacing of the two axes Δ _p and Δ _c .

• Les machines pour lesquelles P₁ est le profil du piston et P₂ est le profil de la capsule, celui-ci s'identifiant à l'enveloppe extérieure de P₁ dans le mouvement planétaire de P₁ relativement à P₂ pour lequel R₁ = S_pE et R₂ = S_cE = (S_p+1)E (famille I).
• Les machines pour lesquelles P₁ est le profil du piston et P₂ est le profil de la capsule, celui-ci s'identifiant à l'enveloppe extérieure de P₁ dans le mouvement planétaire de P₁ relativement à P₂ pour lequel R₁ = S_pE et R₂ = S_cE = (S_p-1)E avec S_p>1 (famille II).
• Les machines pour lesquelles P₁ est le profil de la capsule et P₂ est le profil du piston, celui-ci s'identifiant à l'enveloppe intérieure de P₁ dans le mouvement planétaire de P₁ relativement à P₂ pour lequel R₂ = S_pE et R₁ = S_cE = (S_p-1)E avec S_p>1 (famille III).
• Les machines pour lesquelles P₁ est le profil de la capsule et P₂ est le profil du piston, celui-ci s'identifiant à l'enveloppe intérieure de P₁ dans le mouvement planétaire de P₁ relativement à P₂ pour lequel R₂ = S_pE et R₁ = S_cE = (S_p+1)E (famille IV).

The machines meeting these characteristics can be grouped into four families according to the nature of the member whose shape is defined by P ₁ and according to the comparative values of the radii R ₁ and R ₂ . A distinction should be made:

• The machines for which P ₁ is the profile of the piston and P ₂ is the profile of the capsule, this one identifying with the outer envelope of P ₁ in the planetary movement of P ₁ relative to P ₂ for which R ₁ = S _p E and R ₂ = S _c E = (S _p +1) E (family I).
• The machines for which P ₁ is the profile of the piston and P ₂ is the profile of the capsule, the latter being identified with the outer envelope of P ₁ in the planetary movement of P ₁ relative to P ₂ for which R ₁ = S _p E and R ₂ = S _c E = (S _p -1) E with S _p > 1 (family II).
• The machines for which P ₁ is the profile of the capsule and P ₂ is the profile of the piston, the latter being identified with the inner envelope of P ₁ in the planetary movement of P ₁ relative to P ₂ for which R ₂ = S _p E and R ₁ = S _c E = (S _p -1) E with S _p > 1 (family III).
• The machines for which P ₁ is the profile of the capsule and P ₂ is the profile of the piston, the latter being identified with the inner envelope of P ₁ in the planetary movement of P ₁ relative to P ₂ for which R ₂ = S _p E and R ₁ = S _c E = (S _p +1) E (family IV).

Other machines can be derived from machines belonging to one of the four preceding families. Indeed, one can use a profile P _{2 of} which at least part is identified with the envelope of P ₁ in its movement relative to P ₂ and of which at least a part is external to this envelope in the case of families I or II and is inside this envelope in the case of families III or IV, the different parts connecting to define a closed curve.

The profiles of the piston and of the capsule of these machines have the advantage of being able to be machined by very large series production machines (turning type), which reduces their cost price.

   dans laquelle Z₁ désigne l'affixe du point générateur du profil P₁, chaque point étant précisé par une valeur particulière du paramètre cinématique k dont le domaine de variation est compris entre O et 2Sπ pour parcourir une seule fois la courbe, S est un nombre entier qui désigne l'ordre de symétrie de P₁ par rapport à l'origine du plan complexe et est choisi arbitrairement, E et R_m sont deux longueurs choisies librement à condition que la courbe correspondante ne présente ni point double, ni point de rebroussement, ce qui limite indirectement la valeur du rapport E/R_m.More precisely, the description which follows with reference to the figures listed above, relates to a group of particularly interesting machine profiles, belonging to the family I defined above and whose P ₁ profile of the piston meets the following equation in the complex plane: $${\text{Z}}_{\text{1}}\text{=}\frac{\text{1 + <figure-callout id="2" label="S" filenames="imgf0001.png" state="{{state}}">S</figure-callout>}}{\text{2}}\text{Ee}{}^{\text{i}\frac{\text{k}}{\text{S}}\text{(1-S)}}{\text{+ R}}_{\text{m}}\text{e}{}^{\text{i}\frac{\text{k}}{\text{S}}}\text{+}\frac{\text{1-<figure-callout id="2" label="S" filenames="imgf0001.png" state="{{state}}">S</figure-callout>}}{\text{2}}\text{Ee}{}^{\text{i}\frac{\text{k}}{\text{S}}\text{(1 + S)}}$$

in which Z ₁ designates the affix of the generating point of the profile P ₁ , each point being specified by a particular value of the kinematic parameter k whose range of variation is between O and 2Sπ to traverse the curve once, S is a integer which designates the order of symmetry of P ₁ with respect to the origin of the complex plane and is chosen arbitrarily, E and R _m are two lengths chosen freely provided that the corresponding curve has neither double point nor point of cusp, which indirectly limits the value of the E / R ratio _m .

One of the advantages of these machines is that when the profile P ₁ of the piston corresponds to the above equation, the profile P ₂ of the capsule which is the envelope of P ₁ in the relative planetary movement, also responds to an equation of the same type.

Thus, Figure 1 shows, in section, by a plane perpendicular to the axes Δ _p and Δ _c , parallel, of the piston 1 and the capsule 2, the profile of a piston and a capsule.

These profiles P ₁ for the piston 1 and P ₂ for the capsule 2 correspond to the above equation with a piston 1 of order of symmetry S _p = 2 and a capsule 2 of order of symmetry S _c = 3. E is the distance between the axes Δ _p and Δ _c .

FIG. 2 is a view similar to that of FIG. 1, but in the case where the piston 1 has an order of symmetry S _p = 3 and the capsule 2 an order of symmetry S _c = 4.

FIG. 3 shows another example in which the piston 1 has an order of symmetry S _p = 4 and the capsule 2 an order of symmetry S _c = 3.

It should be noted that the number of axes of symmetry is equal to the order of symmetry.

These three figures correspond to piston and capsule profiles corresponding to the above equation.

In the machines of the following figures, given in nonlimiting examples of the invention, a piston with two axes of symmetry S _p = 2 and a capsule with three axes of symmetry was chosen: S _c = 3.

Referring now to Figures 4, 5 and 6, we will describe a machine according to the invention.

The machine shown comprises a rotor part with axis Δ _p comprising a cylindrical piston 1, a ferromagnetic pinion 2 and a wheel 3, and a stator part with axis Δ _c comprising a pumping cell constituting a hollow volume 4 inside of a capsule 5, a ferromagnetic ring 6 and a bearing surface 7 comprising a bore 8.

In a plane perpendicular to its axis Δ _p , the piston 1 has a hypertrochoidal geometry whose profile P ₁ corresponds to the equation given above and having two axes of symmetry: S _p = 2. It is located in the capsule 5 of axis Δ _c which encloses the hollow cylindrical volume 4 whose section also has a hypertrochoidal geometry of profile P ₂ also corresponding to the above equation and having three axes of symmetry S _c = 3. The axes Δ _p and Δ _c are parallel and distant by a value E.

The piston 1 and the capsule 2 delimit between them three chambers A, B and C which each comprise an inlet equipped with a valve, respectively 9, 10 and 11, located in a lateral flange 12 linked to the stator part, and an exhaust equipped with a valve, respectively 13, 14 and 15. A body 16 in the shape of a crown surrounds the capsule 5 and it has a circular recess 17 which channels the three exhausts towards a single delivery orifice 18.

During operation, the piston 1 performs a planetary movement inside the capsule 5: the axis Δ _p of the piston describes a circle of radius E around the axis fixes Δ _c of the capsule while the piston turns itself around its axis Δ _p .

During this movement, the volume of each chamber A, B and C alternately increases and decreases according to a pulsating movement.

est égal au rapport $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{c}}}}$

. Les bobines 20 sont alimentées successivement. Ainsi, les dents successives 19 du pignon 2 vont être successivement attirées par les bobines successives 20 successivement alimentées, provoquant le roulement avec glissement du pignon 2 dans la couronne 6. On entend, par le fait que les bobines sont alimentées successivement, que les bobines peuvent être alimentées successivement une à une, ou bien que plusieurs bobines successives peuvent être simultanément alimentées et que successivement on alimente la suivante tout en désalimentant la première du groupe alimenté simultanément. Le roulement se fait avec glissement car le rapport du rayon du pignon 2 au rayon de la couronne 6 (à l'extrémité des dents 19 du pignon 2 et des pôles 21 portant les bobines 20) est différent du rapport du nombre N_p de dents 19 du pignon 2 au nombre N_B de bobines 20 de la couronne 6. En revanche, ce rapport $\frac{{\mathit{\text{N}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{c}}}}$

est égal au rapport $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{c}}}}$

, c'est-à-dire au rapport des rayons des cercles C₁ et C₂ définis ci-dessus ayant pour valeur respective : R₁ = S_pE et R₂ = S_cE, le cercle C₁ roulant sans glisser dans le cercle C₂ dans le mouvement du piston 1 de profil P₁ à l'intérieur de la capsule 5 dont le volume creux est le profil P₂ correspondant à l'enveloppe de P₁ dans le mouvement planétaire de C₁ dans C₂.This planetary movement is produced by the pinion 2 and the crown 6. For this purpose, the ferromagnetic pinion 2 of axis Δ _p , which is integral with the piston 1 has N _p teeth 19 and it is located inside the crown. ferromagnetic 6 of axis Δ _c which is integral with the capsule 5 and which is equipped with N _B electric coils 20. The ratio $\frac{{\mathit{\text{NOT}}}_{\mathit{\text{p}}}}{{\mathit{\text{NOT}}}_{\mathit{\text{B}}}}$

is equal to the ratio $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{vs}}}}$

. The coils 20 are supplied successively. Thus, the successive teeth 19 of the pinion 2 will be successively attracted by the successive coils 20 successively supplied, causing the rolling with sliding of the pinion 2 in the crown 6. It is meant, by the fact that the coils are successively supplied, that the coils can be supplied successively one by one, or else several successive coils can be simultaneously supplied and successively the next is supplied while de-energizing the first of the group supplied simultaneously. The rolling is done with sliding because the ratio of the radius of the pinion 2 to the radius of the crown 6 (at the end of the teeth 19 of the pinion 2 and of the poles 21 carrying the coils 20) is different from the ratio of the number N _p of teeth 19 of the pinion 2 to the number N _B of coils 20 of the crown 6. On the other hand, this ratio $\frac{{\mathit{\text{NOT}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{vs}}}}$

is equal to the ratio $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{vs}}}}$

, that is to say the ratio of the radii of the circles C ₁ and C ₂ defined above having the respective value: R ₁ = S _p E and R ₂ = S _c E, the circle C ₁ rolling without sliding in the circle C ₂ in the movement of the piston 1 of profile P ₁ inside the capsule 5, the hollow volume of which is the profile P ₂ corresponding to the envelope of P ₁ in the planetary movement of C ₁ in C ₂ .

, on obtient le mouvement requis du piston 1 dans sa capsule 5. Cependant, afin d'obtenir un mouvement sans frottement et d'éviter ainsi toute nécessité de lubrification, les cercles C₁ et C₂ sont matérialisés par ladite roue 3 et l'alésage 8 de la portée 7 liée à la partie statorique. Ainsi, la roue 3 a un rayon R₁ = S_pE et l'alésage 8 a un rayon R₂ = S_cE. Le roulement de la roue 3 dans l'alésage 8 se fait par l'intermédiaire de bagues de roulement 22, 23 portées par la roue et 24, 25 sur la portée 7.Thus, by this bearing with sliding of the pinion 2 in the crown 6 equipped respectively with teeth and electric coils in the report $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{vs}}}}$

, the required movement of the piston 1 is obtained in its capsule 5. However, in order to obtain a movement without friction and thus to avoid any need for lubrication, the circles C ₁ and C ₂ are materialized by said wheel 3 and the bore 8 of the bearing surface 7 linked to the stator part. Thus, the wheel 3 has a radius R ₁ = S _p E and the bore 8 has a radius R ₂ = S _c E. The rolling of the wheel 3 in the bore 8 is done by means of bearing rings 22, 23 carried by the wheel and 24, 25 on the bearing 7.

The bearing rings 22, 23 on the wheel 3 and 24, 25 on the bearing surface 7 frame an axial magnetic stop consisting of two magnetic rings, 26 carried by the wheel 3, and 27 carried by the bearing surface 7. These rings are axially magnetized and in reverse so as to attract. The rings are slightly set back from the level of the bearing rings.

= $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{c}}}}$

= $\frac{\text{2}}{\text{3}}$

.In the example described, we have: S _p = 2 and S _c = 3; N _p = 20 and N _B = 30 and we have $\frac{{\mathit{\text{NOT}}}_{\mathit{\text{p}}}}{{\mathit{\text{NOT}}}_{\mathit{\text{B}}}}$

= $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{vs}}}}$

= $\frac{\text{2}}{\text{3}}$

.

For operation without friction, there is a very slight clearance between the pinion 2 and the crown 6. Similarly there is a very slight clearance between the piston 1 and the capsule 5, this clearance being able to result from running in.

est différent de $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{c}}}}$

, un léger jeu existant également entre la couronne et l'anneau. Ici, le roulement sans glissement n'est pas produit, comme dans le cas précédent, par l'attirance successive de dents vers les bobines successivement alimentées du fait que le rapport du nombre de dents du pignon au nombre de bobines de la couronne était différent du rapport des rayons du pignon et de la couronne, mais ce mouvement de roulement de l'anneau 28, avec glissement, dans la couronne 6 est ici provoqué simplement par le contact de la roue 3 dans l'alésage 8 et au contraire l'absence de contact entre l'anneau 28 et la couronne 6. Il y a donc roulement sans glissement des pièces en contact : la roue 3 dans l'alésage 8 et l'anneau 28 est ainsi libre de "rouler" avec glissement puisqu'il n'y a pas contact. Comme dans le cas précédent, les bobines électriques 20 sont alimentées successivement.Figure 7 shows a variant of the invention. This FIG. 7 is the equivalent of FIG. 6 and differs from it only by the fact that the pinion 2 is replaced by a simple ferromagnetic ring 28 without teeth. The diameters D ₁ and D ₂ of the ring 28 and of the crown 6 are such that $\frac{{\mathit{\text{D}}}_{\text{1}}}{{\mathit{\text{<figure-callout id="2" label="D" filenames="imgf0001.png" state="{{state}}">D</figure-callout>}}}_{\text{2}}}$

is different from $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{vs}}}}$

, a slight clearance also existing between the crown and the ring. Here, the non-slip bearing is not produced, as in the previous case, by the successive attraction of teeth to the successively supplied coils because the ratio of the number of teeth of the pinion to the number of coils of the crown was different the ratio of the rays of the pinion and the crown, but this rolling movement of the ring 28, with sliding, in the crown 6 is here simply caused by the contact of the wheel 3 in the bore 8 and on the contrary the absence of contact between the ring 28 and the crown 6. There is therefore rolling without sliding of the parts in contact: the wheel 3 in the bore 8 and the ring 28 is thus free to "roll" with sliding since there is no contact. As in the previous case, the electric coils 20 are supplied successively.

Figures 8, 9 and 10 show an alternative embodiment.

In the previous figures, the circles C ₁ and C ₂ of rolling without sliding, linked respectively to the piston and to the capsule and defining the movement of the piston in its capsule, the profile P ₂ of the capsule also being the envelope of the piston in its movement, produced during rolling without sliding of the circle C ₁ linked to the piston, in the circle C ₂ , these circles C ₁ and C ₂ therefore, whose radii are respectively R ₁ = S _p E and R ₂ = S _c E materialized by the wheel 3 and the bore 8, were too small and did not allow electrical coils to be accommodated on the bearing 7 comprising the bore 8. It was therefore necessary, to cause the movement, to produce a crown 6 of large diameter so as to accommodate drive coils 20, associated with a pinion 2 (or a ring 28). The pinion 2 (or the ring 28) was reamed with a hole 29 of sufficient diameter not to come, during its movement, touching the outer periphery of the bearing 7 comprising the bore 8. In fact, the crown 6 and the pinion 2 (or the ring 28) on the one hand and the wheel 3 and the bearing surface 7 were coplanar as seen in FIG. 4.

However, if the radii of the circles C ₁ and C ₂ , which have the value, let us recall it, R ₁ = S _p E and R ₂ = S _c E, are sufficiently large, then the construction can be a little different: the part drive: crown / pinion (ring) can then correspond to the rolling circles C ₁ and C ₂ without sliding. In practice, rings and raceways are used, the dimensions of which correspond exactly to these radii R ₁ and R ₂ while there is a very slight clearance between the driving crown and the pinion.

Figures 8 to 10 thus represent such a construction for a large machine where the eccentricity E between the axes Δ _p and Δ _c is large.

= $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{c}}}}$

.In these figures, we see the piston 1 which comprises at the end a ferromagnetic pinion 30 comprising N _p teeth 31 while the stator part is equipped with a ferromagnetic crown 32 equipped with N _B coils 33. We have $\frac{{\mathit{\text{NOT}}}_{\mathit{\text{p}}}}{{\mathit{\text{NOT}}}_{\mathit{\text{B}}}}$

= $\frac{{\mathit{\text{S}}}_{\mathit{\text{p}}}}{{\mathit{\text{S}}}_{\mathit{\text{vs}}}}$

.

On each side of the pinion 30 is mounted a rolling ring 34 of radius R ₁ = S _p E and on each side of the crown 32 is mounted a raceway 35 of radius R ₂ = S _c E. The radius of the pinion 30 and the radius of the crown 32 are such that there is a very slight clearance at the level of the generator corresponding, at all times, to the contact with rolling without sliding of the rings 34 on the tracks 35. The machine further carries an axial stop constituted by two magnetized rings 36 and 37 carried one, 36, by the rotor assembly and the other, 37, by the stator assembly.

Figures 11, 12 and 13 show three variants of the embodiment of the rolling members of the wheel 3 in the bore 8 and the axial stop carried by the same elements.

In Figure 4, there are rolling members 22, 23, 24, 25 reported framing the magnetic rings 26, 27 of the axial stop.

In FIG. 11, there are no added bearing rings. The magnetic ring 26 is mounted on the wheel which is clamped between a shoulder and a cap 38. Likewise, the magnetic ring 27 is mounted in the bearing 7 between a shoulder and a cover 39.

In FIG. 12, as in FIG. 11, there are also no added bearing rings, the bearing is made directly on the rectified surfaces of the wheel 3 and of the seat 7. Here, the magnetic rings are framed by ferromagnetic rings: 40 and 41 for the wheel 3 and 42 and 43 for the seat 7. These rings are slightly recessed in relation to the rolling surfaces. The set of magnetic rings and ferromagnetic rings constitutes a passive magnetic reluctance stop.

Finally, in FIG. 13, there are, as in FIG. 4, bearing rings 22, 23, 24 and 25 and also, as in FIG. 12, ferromagnetic rings 40, 41, 42 and 43.

Claims (6)

1. A positive-displacement machine having orbital motion and including a piston (1) which is cylindrical in the mathematical sense, which has an axis Δ_p, which is rotary, and which is situated in a cylindrical casing (5) that has an axis Δ_c. said piston (1) having a cross-section that has S_p axes of symmetry in a plane perpendicular to its axis Δ_p, said casing (5) delimiting a hollow volume (4) whose cross-section in a plane perpendicular to its axis Δ_c has S_c axes of symmetry, S_p and S_c differing from each other by unity, the axes Δ_p and Δ_c being parallel and separated by a distance E, the piston (1) and the casing (5) delimiting at least three chambers (A, B, C) between them, and the casing including at least one suction inlet (9, 10, 11) and one delivery outlet (13, 14, 15), said positive-displacement machine being characterized in that it further includes a ferromagnetic sprocket (2, 30) which has an axis Δ_p, which is secured to the piston (1), which has N_p teeth, and which is disposed inside a ferromagnetic toothed ring (6, 32) which has an axis Δ_c and which is secured to the casing (5), said toothed ring being provided with N_B electrical windings (20, 33) disposed radially, in that the ratio N_p/N_B is equal to the ratio S_p/S_c, and in that the N_B electrical windings (20, 33) of said toothed ring (6, 32) are powered successively.
2. A positive-displacement machine according to claim 1, characterized in that it further includes a wheel (3) which has an axis Δ_p, which is secured to the piston (1), and which has a radius R₁ = S_pE, said wheel being disposed inside and rolling without slip inside a circular bore (8) which has an axis Δ_c and is provided in a support (7) that is secured to said toothed ring (6), the bore (8) having a radius R₂ = S_cE.
3. A positive-displacement machine according to claim 1, characterized in that a rolling ring (34) of radius R₁ = S_pE is situated on each side of said ferromagnetic sprocket (30), and a rolling path (35) of radius R₂ = S_cE is situated on each side of said ferromagnetic toothed ring (32), the radii of said sprocket (30) and of said toothed ring (32) being such that there is a small amount of clearance between the sprocket and the toothed ring on the generator line corresponding at all times to rolling contact without slip between said rolling ring (34) and said rolling path (35).
4. A positive-displacement machine having orbital motion and including a piston (1) which is cylindrical in the mathematical sense, which has an axis Δ_p, which is rotary, and which is situated in a cylindrical casing (5) that has an axis Δ_c, said piston (1) having a cross-section that has S_p axes of symmetry in a plane perpendicular to its axis Δ_p, said casing (5) delimiting a hollow volume (4) whose cross-section in a plane perpendicular to its axis Δ_c has S_c axes of symmetry, S_p and S_c differing from each other by unity, the axes Δ_p and Δ_c being parallel and separated by a distance E, the piston (1) and the casing (5) delimiting at least three chambers (A, B, C) between them, and the casing (5) including at least one suction inlet (9, 10, 11) and one delivery outlet (13, 14, 15), said positive-displacement machine being characterized in that the machine further includes a ferromagnetic collar (28) which has an axis Δ_p, which has an outside diameter D1, which is secured to the piston (1), and which is disposed inside a ferromagnetic toothed ring (6) which has an axis Δ_c, which has an inside diameter D2, and which is secured to the casing (5). said toothed ring (6) being provided with a plurality of electrical windings (20) disposed radially and powered successively, the ratio D₁/D₂ being different from the ratio S_p/S_c, a small amount of clearance existing between those respective generator lines of the collar (28) and of the toothed ring (6) which are closest together and which are situated in the plane containing the axes Δ_p and Δ_c, and in that the machine further includes a wheel (3) which has an axis Δ_p, which is secured to the piston (1), and which has a radius R₁ = S_pE, said wheel (3) being disposed and rolling without slip inside a circular bore (8) which has an axis Δ_c, and which is provided in a support (7) that is secured to said toothed ring, the bore having a radius R₂ = S_cE.
5. A positive-displacement machine according to any one of claims 1 to 4, characterized in that it includes an axial magnetic abutment composed of at least one pair of magnetized rings (26, 27), one of which (27) is secured to the fixed portion (5, 6, 7), and the other of which (26) is secured to the moving portion (1, 2, 3).
6. A positive-displacement machine according to any preceding claim, characterized in that, in a plane perpendicular to its axis Δ_p, said piston has a cross-section that is hypertrochoidal in geometrical shape, and in that said casing delimits a hollow volume (4) whose cross-section in a plane perpendicular to its axis Δ_c is hypertrochoidal in geometrical shape.

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