FR2832768A1 - Hydrostatic volumetric multi-stroke engine comprises stator receiving rotor and several radially located contact parts supported against circulation path - Google Patents

Abstract

The multi-stroke engine comprises a stator (1) receiving a rotor (2) and has several contact parts (3) radially located between the stator and rotor which are supported against a circulation path (5). There are several delivery chambers (6) which, during relative rotation of the stator and rotor, change volume by the forced movement of the contact parts. The circulation path has a periodic function in the peripheral direction. The contact parts each comprises two contact zones (3a,3b) separated from each other in the peripheral direction and between which a delivery chamber is formed. The distance taken on a straight line segment between the contact zones corresponds to the half period of the periodic function of the circulation path.

Description

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Field of the invention
The present invention relates to a hydrostatic multi-stroke volumetric machine, in particular a motor, comprising a stator receiving a rotor, and having several contact members disposed radially between the stator and the rotor to bear against a circulation path, as well as several chambers discharge which, during the relative rotation of the rotor and the stator, change volume by the forced movement of the contact members, the flow path having a form of periodic function in the peripheral direction.

Description of the Prior Art
Volumetric machines of the type defined above are known, for example in the form of slowly rotating radial piston engines, in the field of hydraulics. Depending on whether the piston-shaped contact member is movably mounted in the stator and bears against a circulation path on the outer peripheral surface of the rotor or is held in the rotor and rests on a circulation path of the inner peripheral surface of the stator, there will be an internal support or an external support (radial support) of the contact members against the circulation path.

 The peripheral direction of the circulation path, produced in the printed form of a periodic function, results in cavities and bosses in the form of a cam and gives a volumetric machine with several strokes. The contact members of radial piston motors generally consist of star-shaped pistons which, in the case of known motors, are supported externally by means of a cylindrical roller, indirectly on the path traffic. The torque is generated by the linear contact between the cylindrical rollers and the circulation path. The surface pressure thus produced limits the operation to high pressures and high temperatures and a low viscosity of the hydraulic fluid. To guarantee the permanent support of the contact members against the circulation path, mechanical driving members are required, for example springs and hydraulic pressures supplied by hydraulic control circuits.

Aim, object and advantage of the invention
The present invention aims to develop a volumetric machine of the type defined above offering a higher power density and having a simpler construction.

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This problem is solved according to the invention in that the contact members each have two contact zones, spaced from one another in the peripheral direction of the circulation path to bear against this circulation path, zones between which a discharge chamber is formed each time, and the distance taken on a straight line segment between the contact zones of one another corresponds essentially to the half period of the periodic function of the path of circulation, the contact members being pivoting.

The essential characteristic of the invention consists in carrying out the variation in volume of the delivery chambers not as in volumetric machines known according to the state of the art by radial strokes but by a tilting or pivoting movement, saving space. , for the contact members in the peripheral direction. The volumetric machine according to the invention thus has a compact construction. The ratio of congestion to transmitted torque is low. The necessary means in parts are reduced and the insertion or particular holding members of the contact members become unnecessary.

The volumetric machine according to the invention can be used as a slowly rotating motor, for example as a direct wheel drive motor or a motor of a rotation mechanism. The volumetric machine has only very low hydrodynamic friction losses and is practically free of play for changes in load direction. The manufacturing cost is reduced and the operational safety high.

According to an advantageous development of the invention, the contact members are each pivotally or tiltably housed in a concave housing in particular in the form of a cylinder part. This type of assembly is very simple to manufacture.

The contact members are advantageously balanced from the hydrostatic point of view in their mounting in the housing. Thus, the forces resulting from the hydrostatic pressure in the discharge chambers act directly between the circulation path and the housings of the contact members and the torque is thus essentially created by the thrusts. The contact members do not practically participate in this case in the development of the couple. They only serve to seal the delivery chambers. By creating the couple,

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 from hydrostatic pressure there will be only little friction and the mechanical losses will be reduced.

 Advantageously, the balancing or hydrostatic compensation force is dimensioned to be less than the application force. There is thus a force in the direction of the housing used for sealing.

 Hydrostatic balancing of the contact members can be carried out in a simple manner in that each time, radially between the contact member and the corresponding housing, there is a pressure chamber connected to the corresponding delivery chamber by at least one machined channel. in the contact organ.

 According to an embodiment of the invention in which the housings are provided in the rotor, the contact members are pivotally mounted each around an instantaneous pole moving on a circular path concentric with the axis of rotation of the rotor so that the volumetric machine has an external support for the support members.

 An advantageous development of the volumetric machine from the point of view of the simplicity of the security of the control is characterized in that it comprises hydraulic liquid supply and delivery channels capable of being periodically connected to the delivery chambers, the orifices of the channels being located in an area swept by the pressure chambers during the relative rotation of the rotor and the stator.

 The pressure chambers thus serve not only for hydrostatic balancing of the contact members but also for supplying the discharge chambers.

 Another advantageous development of the invention is characterized in that the housings are made in the stator and the contact members can tilt around a pole lying on a circular path concentric with the axis of rotation of the rotor. This is a volumetric machine with internal support of the support members, the circulation path being provided on the rotor.

 Such an arrangement is particularly suitable for a development of the invention according to which axially between on the one hand a housing cover and on the other hand the rotor and the contact members, there is provided a device for the compensation of the axial interval.

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 In such a volumetric machine with internal support of the support members against the circulation path, in the event of wear of the lateral sealing surfaces, an adjustment is made. The device may also include a plate for compensating for the axial gap, this plate being pushed by the force of a spring and / or by hydrostatic forces in the direction of the moving parts.

 Advantageously, for controlling the machine, there are hydraulic fluid supply and discharge channels connected periodically to the discharge chambers and the orifice of which is located in an area in which there are the discharge chambers and during the relative movement. between the rotor and the stator, this area is traversed by the cams for the circulation path by turning with the rotor.

 To minimize leakage at the delivery chamber in all variants of the volumetric machine according to the invention, it is advantageous for the contact members to include, at the contact areas, sealing bars housed in grooves.

 The sealing bars can have a convex contour, in particular partially cylindrical. Another development of the invention provides for producing sealing bars in the form of rollers.

 Optimal operation of the sealing bars is obtained if they are stressed in the direction of the circulation path by a spring force and / or by the pressure resulting from the delivery chamber.

Drawing
The present invention will be described below in more detail with the aid of exemplary embodiments represented in the appended drawings in which: FIG. 1 is a block diagram of a volumetric machine according to the invention, - Figure 2 shows the development of the periodic function printed on the circulation path of the volumetric machine, - Figure 3 is a longitudinal section of a volumetric machine with external support, - Figure 4 is a section of the volumetric machine according to line IV-
IV of Figure 3,

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- la figure 7 montre un organe de contact équipé de barrettes d'étanchéité chargées par une force de ressort, - la figure 8 montre un organe de contact avec des barrettes d'étanchéité sollicitées par une force de ressort ou une pression hydrostatique, - la figure 9 montre un organe de contact avec des barrettes d'étanchéité sollicitées par une force de ressort. FIG. 5 is a longitudinal section of a volumetric machine with internal support, FIG. 6 is a section of the volumetric machine cut along line VI-VI of FIG. 5,

- Figure 7 shows a contact member fitted with sealing bars loaded by a spring force, - Figure 8 shows a contact member with sealing bars loaded by a spring force or hydrostatic pressure, - the Figure 9 shows a contact member with sealing bars biased by a spring force.

Description of embodiments
The volumetric machine according to the invention comprises a stator 1 concentrically housing a rotor 2 receiving several contact members 3 in housings 4 having a partial cylinder shape. The inner peripheral surface of the stator 1 is provided with a circulation path 5 in which is printed a periodic function of periods T. This periodic function appears in the form of cavities and bosses repeating regularly in the circulation path or trajectory 5 As the contact members 3 rotate with the rotor and thus come to bear against the peripheral circulation path 5, this machine is called machine with external support. In principle, in this type of machine, it is also possible to immobilize the rotor 2 and to rotate the stator 1. A machine provided with an internal support will be described below in more detail.

 Each contact member 3 has two contact zones 3a, 3b intended to come into abutment against the circulation path 5; between these contact zones a delivery volume is formed each time 6. The contact members 3 are pivotable about an axis, each in a housing 4. During the relative movement of the rotor 2 and the stator 1 by an angle a, there will not only be the displacement of each contact member 3 in the peripheral direction of the circulation path 5 but, due to the support of the contact zones 3a, 3b against the circulation path 5, this will also be reflected by tilting in the housing 4.

The axis around which each contact member 3 rocks constitutes an instantaneous pole M displaced by the rotation of the rotor 2 on a circular path K around the axis of rotation R of the rotor 2.

 The circular trajectory K can correspond to the center of the curve of the periodic function of the circulation path 5 like this

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 appears in the present exemplary embodiment. But it is also possible to have an offset of the circular path K relative to the center of the functional curve.

 In the case of the combined movement described, of the contact member 3, the delivery volume 6 changes: for a complete period this volume changes from a minimum value to a maximum value and then returns to a minimum value. At each rotation of the rotor 2, there is for a number n of periods of the function represented by the circulation path 5 and a number m of contact members, a pumped volume (in the case of a pump) or a volume drawn (in the case of an engine) corresponding to the product n * m. In the present embodiment, this corresponds to 7 periods (corresponding to the 7 bosses or cavities) and 9 contact members giving a volume equal to 63 times the unit volume.

 Advantageously, radially between the contact members 3 and the circulation path 5 of the stator 2, there is a gap S made sealed by means which will be described later. The interval S compensates for manufacturing tolerances and deformations of the parts.

 FIG. 2 shows the curve F of the periodic function formed by the circulation path 5 and having a period T. The line segment represented and not the ends is located on the functional curve F and the length of which corresponds substantially to half of the length of the period T / 2, each corresponds to the distance A between the contact zones 3a, 3b of the contact member 3. The center of the segments is located (independently of the position of the linear segment on the curve F) always on the zero line or is offset a small distance (e) from this zero line.

 Applied to the contact members 3, this means that during the movement of the contact members 3 caused by the shape of the circulation path 5 and by the relative rotation of the rotor 2 relative to the stator 1, there is no stroke but a rocking movement around the instantaneous pole M.

 In the volumetric machine according to FIG. 3 constructed according to the principle of the machine represented in FIG. 1, and constituting, in the present embodiment, a hydrostatic rotary motor rotating slowly, the stator 1 is installed between two bearing covers 7, 8, and forms therewith the body or housing of the machine. The delivery volumes 6 are each surrounded by a contact member 3, the

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 trajectory or traffic path 5 and the side landing caps or caps 7.8. The bearing covers 7,8 receive a drive shaft 9 on which a toothed wheel 9a is formed and which is coupled by a groove 9n to the rotor 2. The right bearing cover or cap 8 according to the figure comprises the channels d hydraulic fluid supply and delivery 1.

 As results from the view in FIG. 4, radially between each volume 4 and the corresponding contact member 3, a pressure chamber 11 has been formed each time at which the orifices D of the supply channels are located. and hydraulic fluid delivery 10. The pressure chambers 11 are connected by channels 12 machined in the contact members 3 to be connected to the delivery volume 6. Thus, on the one hand, the supply channels are connected and hydraulic fluid discharge 10, during the rotation of the rotor 2, periodically at the discharge volume 6, and, on the other hand, the effect of the hydrostatic pressure in the pressure chambers 11 ensures the hydrostatic discharge of the organs of contact 3.

 In this construction, the hydrostatic pressure acts in principle directly between the circulation path 5 of the stator 1 and the housing 4 of the rotor 2. The contact member 3, discharged or balanced from the hydrostatic point of view, has only the function of a screw with respect to the outside, the delivery volume 6 and sealing it as well as that of the pressure chamber 11, that is to say ensuring in a way the imprisonment of the hydraulic liquid.

 The torque is provided mainly directly by hydrostatic forces. Unlike machines with force transmission by jacks and rollers circulating on a circulation path and indirect creation of torque, to transmit a force in the present case no part is necessary. It suffices to push the parts against each other to ensure sealing, namely the sealing bars which will be described in connection with FIGS. 7, 8 and 9 applied against the circulation path 5 and the contact members 3 in the housings 4. This is why the friction is reduced which minimizes the mechanical losses.

 Only half of the orifices D concentrically distributed in the hydraulic fluid supply and delivery channels 10, that is to say each second orifice is permanently subjected to a high pressure Du during operation and the other half DN is

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 permanently at low pressure. For the discharge chambers 6 connected to the high pressure DH orifices, FIG. 4 shows the direction of the resulting hydrostatic force, applied to the contact members 3 (force arrow Fp). The hydrostatic forces which are applied with a lever arm h with respect to the axis R of the rotor 2 and thus create a torque, cause the rotor 2 to rotate. As there are several such forces distributed at the periphery tending to rotate the rotor will have a very high degree of regularity.

 The variant represented in FIGS. 5 and 6 of the volumetric machine according to the invention comprises housings 4 for the contact members 3 in the stator 1. Conversely, the circulation path 5 is located on the outer peripheral surface of the rotor 2. It it is thus a machine with internal support for the contact members 3. The delivery chambers 6 of this variant of the volumetric machine according to the invention are thus included radially between the contact members 3 and the rotor 2.

 For the same size as that of the variant described above, there will be here a larger number of contact members 3 (in the present embodiment there will be 10 contact members 3). While in the variant with external support, the instantaneous poles M of the contact members 3 rotate in synchronism with the rotation of the rotor 2 on the circular path K, in the variant with internal support, the contact members perform only one rotational movement around the fixed poles P.

 The number of orifices D of hydraulic fluid supply and delivery channels (here these are directly channels arriving in the delivery chamber 6) corresponds to the number of contact members 3. The orifices D are distributed in a zone swept during the relative movement of the rotor 2 and the stator 1 by the cams 2a of the circulation path 5 rotating with the rotor 2. The orifices D alternately supply high pressure and low pressure by an appropriate control, not shown in the figures. The pressure chambers 11 and the channels 12 between the discharge chambers 6 and the pressure chambers 11 can be of smaller size than in the variant of FIGS. 3 and 4 because they serve only for hydrostatic discharge and not for supplying in hydraulic fluid from the discharge chambers 6.

 Axially between the bearing cover 8 and the rotor 2 of the contact members 3 there is provided a device for compensating for

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 the axial gap which includes a plate 13; this plate can be urged by the spring force and in the present embodiment also by hydrostatic forces in the direction of the rotor 2 and the contact members 3. When the front faces are closed, this part undergoes automatic adjustment.

 FIGS. 7-9 (detailed view of the variant embodiments of FIGS. 3 and 4) show several possibilities for sealing the delivery chambers 6. For this, grooves 14, 15 are provided at the contact zones 3a, 3b with sealing bars 16,17 occupying the entire width of the contact members 3. The sealing bars 16,17 are biased towards the circulation path 5 by the force developed by springs.

 In the embodiments of FIGS. 7 and 8, the sealing bars have a convex contour. In the case of the sealing bars 16, 17 of FIG. 7, this result is obtained by a segment having partly the shape of a cylinder. A groove N produced in the sealing bars 16,17 each time connects the rear chamber to the delivery chamber 6 so that the sealing bars 16,17 are stressed by hydraulic pressure in the direction of the circulation path 5.

 The sealing bars 16, 17 of FIG. 8 are produced in the form of rollers and receive the hydraulic pressure by the channels 18, 19 connecting the grooves 14, 15 to the discharge chamber 6 and to the pressure which prevails in this bedroom. The sealing bars 16, 17 shown in FIG. 9 each have a contour with a sharp edge relative to the circulation path 5.

Claims (13)

 CLAIMS 1) Hydrostatic multi-stroke volumetric machine, in particular motor, comprising a stator (1) receiving a rotor (2), and having several contact members (3) arranged radially between the stator (1) and the rotor (2) for come to bear against a circulation path (5), as well as several delivery chambers (6) which, during the relative rotation of the rotor (2) and the stator (1), change in volume by the forced movement of the organs of contact (3), the circulation path (5) having a form of periodic function in the peripheral direction, characterized in that the contact members (3) each comprise two contact zones (3a, 3b), spaced apart one from the other in the peripheral direction of the circulation path (5) to bear against this circulation path (5), zones between which a discharge chamber (6) is formed each time, and the distance A taken on a straight line segment between the contact areas ( 3a, 3b) one from the other corresponds essentially to the half period T / 2 of the periodic function of the circulation path (5), the contact members (3) being pivoting.  2) hydrostatic volumetric machine with several strokes according to claim 1, characterized in that the contact members (3) are pivotally mounted in each case in a concave housing (4) in particular a housing in the form of a cylinder part.  3) Hydrostatic volumetric machine with several strokes according to claim 2, characterized in that the contact members (3) are mounted in their housing (4) while being in hydrostatic equilibrium.  4) Hydrostatic volumetric machine with several strokes according to claim 3, characterized in that radially between the contact member (3) and the corresponding housing (4) there is a pressure chamber (11) connected by at least one channel ( 12) machined <Desc / Clms Page number 11>  in the contact member (3) to the corresponding delivery chamber (6).  5) hydrostatic volumetric machine with several strokes according to claim 2, characterized in that the housings (4) are produced in the rotor (2) and the contact members (3) are pivotable respectively around an instantaneous pole M movable on along a circular path K concentric with the axis of rotation R of the rotor (2).  6) Hydrostatic volumetric machine with several strokes according to claim 5, characterized in that it comprises channels (10) for supplying and discharging hydraulic fluid capable of being periodically connected to the discharge chambers (6), the orifices (D) channels being located in an area swept by the pressure chambers (11) during the relative rotation of the rotor (2) and the stator (1).  7) hydrostatic volumetric machine with several strokes according to claim 2, characterized in that the housings (4) are made in the stator (1) and the contact members (3) can tilt around a pole (P) being on a circular path (K) concentric with the axis of rotation (R) of the rotor (2).  8) hydrostatic volumetric machine with several strokes according to claim 7, characterized in that axially between on the one hand a housing cover (8) and on the other hand the rotor (2) and the contact members (3) it an axial gap compensation device is provided (plate 13).  9) Hydrostatic volumetric machine with several strokes according to claim 7, characterized by <Desc / Clms Page number 12>  hydraulic fluid supply and discharge channels which can be periodically connected to the discharge chambers (6), and the orifices of which are in an area in which the discharge chambers (6) are located and during the relative rotation rotor (2) and stator (1) this area is swept by cams (2a) of the circulation path (5) rotating with the rotor (2). 10) hydrostatic volumetric machine with several strokes according to claim l, characterized in that the contact members (3) are provided with sealing bars (16,17) provided in grooves (14,15) at each contact zone (3a, 3b).  11) Hydrostatic volumetric machine with several strokes according to claim 10, characterized in that the sealing bars (16,17) each have a convex outline in particular in the form of a cylinder part.  12) Hydrostatic volumetric machine with several strokes according to claim 11, characterized in that the sealing bars (16,17) are rollers. 13) Hydrostatic volumetric machine with several strokes according to claim 10, characterized in that the sealing bars (16,17) are biased towards the circulation path (5) by a spring force and / or by the thrust of the discharge chamber (6).