WO2015162237A1

WO2015162237A1 - Hydraulic machine with radial pistons comprising a casing not exhibiting symmetry of revolution

Info

Publication number: WO2015162237A1
Application number: PCT/EP2015/058875
Authority: WO
Inventors: Philippe Lucienne; Gilles Lemaire
Original assignee: Poclain Hydraulics Industrie
Priority date: 2014-04-25
Filing date: 2015-04-24
Publication date: 2015-10-29
Also published as: FR3020415A1; FR3020415B1; CN106536925B; CN106536925A

Abstract

The present invention relates to a hydraulic machine comprising a casing (100), a multi-lobed cam (200), a cylinder block (300) comprising a plurality of cylinders (310), pistons (500) translationally mobile in the cylinders (310) and resting against the lobes of the cam (200), and a fluid-distribution assembly connected to the cylinders, the cam (200) and the cylinder block (310) being capable of relative rotation about an axis of rotation (O-O), and is characterized in that the outer envelope of the casing (100) does not exhibit symmetry of revolution about the axis of rotation (O-O) and has a smaller dimension opposite a cam sector (110) that has no function lobe.

Description

Hydraulic radial piston machine comprising a non-symmetrical case of revolution

The present invention relates to the field of hydraulic motors and pumps.

More specifically, the present invention relates to the field of hydraulic motors and pumps with radial pistons.

The Applicant has already proposed numerous models of hydraulic motors and pumps with radial pistons.

As shown in longitudinal section in FIG. 1 and in cross-section in FIG. 2, the radial piston hydraulic motors generally comprise, in the chamber of a housing 10, a hydraulic / mechanical transducer composed of:

a multilobe cam 20, formed for example on the internal surface of an element 22 of the casing,

- a cylinder block 30 mounted relative rotation in the housing 10,

a shaft 40 connected to rotation with the cylinder block 30,

- Pistons 50 guided in radial sliding in respective cylinders 52 of the cylinder block and bearing on the lobes of the cam 20, the number of pistons 50 being different from the number of lobes formed on the cam 20, and

a distributor 60 adapted to apply successively and in a controlled manner to the pistons 50 a fluid coming from a source under pressure, so that the successive support of the pistons 50 on the lobes of the cam 20 causes the relative rotation of the cylinder block 30 and elements connected to it relative to the housing 10.

Such a system is reversible. That is, if the shaft 40 or a member mechanically connected thereto is rotated by an external mechanical member, the engagement of the pistons 50 and the multilobe cam 20 generates successive pressures in the cylinders 52. , so that the hydraulic / mechanical transducer shown in Figures 1 and 2 is then not a motor but a hydraulic pump. An exemplary embodiment of such a hydraulic machine comprising an outer multilobe cam associated with a cylinder block and internal radial pistons, is described in the document FR 2872227.

It has been found that in certain machine configurations, congestion constraints in a preferred direction can prevent and / or make difficult the use of aforementioned axisymmetric radial piston machines.

In this context the invention aims to improve the state of the art.

This object is achieved according to the present invention by means of a hydraulic machine comprising:

a housing,

a cam having a plurality of lobes,

a cylinder block having a plurality of cylinders,

pistons movable in translation in the cylinders and resting on the lobes of the cam, and

a fluid distribution assembly in connection with the cylinders, the cam and the cylinder block being capable of relative rotation about an axis of rotation,

characterized in that

the outer casing of the casing is not symmetrical of revolution about the axis of rotation and has a smaller dimension facing a sector of the cam devoid of functional lobes.

Other features, objects and advantages of the present invention will appear on reading the detailed description which follows, made with reference to the accompanying drawings, given by way of non-limiting example and in which:

Figures 1 and 2 previously described respectively represent a longitudinal sectional view of a hydraulic motor known from the state of the art, according to the sectional planes referenced II in Figure 2 and a cross-sectional view of the same motor according to the sectional plane referenced II-II in Figure 1, FIG. 3 represents a cross-sectional view of a hydraulic machine according to the present invention and

Figures 4 and 5 show similar cross-sectional views of hydraulic machines according to variants of the present invention.

FIG. 3 appended hereto shows a hydraulic machine comprising a housing 100, an external cam 200 centered on an axis of rotation 0-0 and comprising a plurality of lobes distributed on its radially inner surface, directed towards the axis 0-0, a cylinder block 300 housed in the center of the cam 200 and having a plurality of cylinders 310 oriented radially with respect to the 0-0 axis of rotation and opening radially on the outside of the cylinder block 300 and pistons 500 mobile translation in the cylinders 310 and resting on the lobes of the cam 200.

Each lobe 210 of the cam 200 includes a concave belly

212 larger radius relative to the 0-0 axis flanked by two vertices 214 leading to adjacent lobes.

The hydraulic machine illustrated in FIG. 3 also comprises a fluid distribution assembly in connection with the cylinders 310. However, this fluid distribution assembly which may be in accordance with the known provisions of the state of the art, for example such as illustrated in Figure 1, will not be described in more detail later.

As indicated above, according to the present invention, the outer casing of the casing 100 is not symmetrical about the rotation axis 0-0 and has a smaller dimension facing a sector 110 of the cam without Functional lobe.

The term "functional lobe" is understood to mean a zone of the cam which induces a radial displacement of the facing piston during the relative rotational movement of the cylinder block 300. Thus, the term "sector of the cam without a functional lobe" means a sector 110 of the cam 200 whose profile does not induce radial displacement of the piston facing during the relative rotational movement of the cylinder block 300. As indicated above, the main object of the present invention is to propose a hydraulic machine adapted to be placed closer to an object, for example as close as possible to a thermal block of a vehicle or even closer to a floor of a vehicle. vehicle.

The invention is of course not limited to these two particular cases and extends to all applications in which one may wish to bring a hydraulic machine an object.

In Figure 3 attached this object is shown schematically under the reference O and will not be described in more detail later.

More precisely, as can be seen in FIG. 3, preferably appended according to the invention, the outer casing of the casing 100 comprises, at the level of the aforementioned sector 110, a flat portion 112 which extends perpendicularly to a radius drawn up from the axis rotation 0-0.

It will be observed that preferably the machine has a plane of symmetry passing through the axis 0-0 and the aforementioned transverse radius to the flat portion 112.

Those skilled in the art will understand that the invention thus creates a zone 110 of inactive cam, without stroke, and of minimum crankcase thickness in the angular zone 110 where it is desired to reduce the bulk.

The minimum radial dimension in the direction of the non-stroke cam region is directly related to the diameter of the cylinder block 300.

At the neutralized zone 110, the cam 200 has a hollow profile, that is to say concave in the direction of the 0-0 axis of rotation.

More precisely still, preferably at the sector 110 the profile of the cam 200 ensures a transition between two vertices 212 and at the sector 110 the internal profile of the cam 200 is cylindrical of revolution centered on the axis of rotation 0- 0. This cam profile at the sector 110 corresponds to a retracted position of the pistons 500, that is to say the diameter of a peak 214 of the cam lobe.

The outer dimension of cam 200 and housing 100 can be adjusted accordingly. It suffices to maintain the minimum thickness necessary for holding the cam 200 knowing that the pistons exert little thrust on the neutralized zone 110 without a lobe.

If necessary, it is possible to provide a non-regular distribution of the cam lobes, mixed with the application of a homokinetic motor principle by lobe as described in FR 2 872 227.

The neutralized sector 110 does not include an active cam.

According to the particular example shown in FIG. 3 and not limiting, the external cam 200 has five active lobes distributed over an angular sector of 300 °, the neutralized sector 110 has an angular opening of the order of 60 ° (its angular aperture is therefore equal to the angular opening of a lobe and corresponds to the deletion or erasure of a lobe relative to a conventional cam), and the cylinder block 300 comprises eight cylinders 310 housing a respective piston 500.

On the neutralized cam portion 110 which does not comprise an active cam portion, that is to say no functional lobe, the cam shape places the pistons 500 which successively face each other, in the retracted position in the cylinder block 300. There is no motor action on this neutralized portion 110. Nevertheless, the motor lobes can be adapted without difficulty by the designer, in particular arranged in a non-regular distribution, to regularize the cycle and obtain a homokinetic motor. One condition is that there are other driving actions on other lobes of the cam while the pistons pass over the neutralized sector 110 so that the engine can make a complete turn.

Preferably the pistons placed opposite the neutralized zone 110 are maintained in low pressure supply to minimize friction and losses.

Specifically for this the supply ports provided on the distributor 60 at the neutralized sector 110 are placed in low pressure supply to maintain the pistons 500 in retracted position at this level. In FIG. 3, these orifices are referenced 62 and More specifically, to avoid biasing the pistons 500 radially outwardly at the neutralized sector 110, the aforementioned orifices 62 and 64 provided at the neutralized sector 110 may be:

. either not powered,

.be connected to the low pressure inside the crankcase,

. connected to a pressure of feeding, low pressure,

. either connected to a selected low specific pressure.

Advantageously, the thickness of the metal on the neutralized sector 110 can be reduced because the pistons 500 opposite are always supplied with low pressure which allows to gain even more diameter.

FIG. 4 shows an alternative embodiment according to the present invention which differs from the embodiment illustrated in FIG. 3 and previously described in that the central shaft 40 connected to rotation with the cylinder block 30 is hollow, that is to say tubular, to allow the passage of an auxiliary shaft, for example a shaft coupled to a differential and rotatably connected with a cardan driving a wheel. In Figure 4 the central channel formed in the shaft 40 to allow the passage of the auxiliary shaft, is referenced 42.

According to a particular and nonlimiting embodiment, to be able to integrate the machine according to the present invention under a vehicle body, without reducing the ground clearance, the maximum external diameter Dl of the machine (excluding neutralized sector 110) is less than 130mm and the diameter D2 of the channel 42 is of the order of 30mm. As a result the radius RI of the machine, outside the neutralized sector 110, to integrate the power transformation function is of the order of 50mm. By adopting a 30% distribution for the cam, 60% for the piston function and 10% for the inner shaft 40, the radial dimensions for the cam 100 are R2 (at a belly 212 of the cam) of the cam. order of 15mm, for the piston function, cylinder block included, R3 of the order of 30mm and for the inner shaft 40 R4 of the order of 5mm. According to another optional feature of the invention, to geometrically balance the machine, it may comprise several sectors 110 lacking functional lobe, equidistributed around the axis 0-0, for example three sectors 110 equidistributed around the axis 0-0.

According to an advantageous embodiment, as illustrated in FIG. 5, two diametrically opposed sectors 110 can be provided with respect to the 0-0 axis. The machine then comprises two flats 112 diametrically opposite with respect to the 0-0 axis. This arrangement makes it possible to further reduce the transverse dimension of the machine in the direction perpendicular to the flats 112.

Naturally, the present invention is not limited to the particular embodiments that have just been written, but extends to any variant that conforms to its spirit.

If necessary, it is possible to produce a hydraulic machine, whether it be a motor version or a pump version, by coaxial stacking of several subassemblies of the type illustrated in FIG. 3, by angularly shifting the pistons of the different subsets. Stacking of several subassemblies makes it possible to increase the cubic capacity and hence the overall machine torque thus formed.

Those skilled in the art will appreciate that preferably the machine according to the present invention has a symmetry with respect to a plane P orthogonal to the flat part 112.

Claims

claims

1. Hydraulic machine comprising:

a housing (100),

a cam (200) comprising a plurality of lobes,

a cylinder block (300) comprising a plurality of cylinders (310),

pistons (500) movable in translation in the cylinders (310) and resting on the lobes of the cam (200), and

- A fluid distribution assembly in connection with the cylinders, the cam (200) and the cylinder block (310) being capable of relative rotation about an axis of rotation (O-O), characterized in that:

- The outer casing of the housing (100) is not symmetrical of revolution about the axis of rotation (O-O) and has a smaller dimension with respect to a sector (110) of the cam without functional lobe.

2. Machine according to claim 1 characterized in that the cam (200) is defined by a cylinder of revolution centered on the axis of rotation (O-O) at its sector (110) devoid of functional lobe.

3. Hydraulic machine according to one of claims 1 to 2 characterized in that the profile of the cam (200) extends the peaks (214) of adjacent cam lobes at the sector (110) devoid of functional lobe.

4. Machine according to one of claims 1 to 3 characterized in that the outer casing of the casing (100) has a flat (112) facing the sector (110) of the cam (200) devoid of functional lobe.

5. Machine according to claim 4 characterized in that the housing (100) has a minimum thickness at the sector (110) of the cam placed opposite the flat (112).

6. Machine according to one of claims 1 to 5 characterized in that the angular aperture of the cam sector (110) devoid of functional lobe covers an angular aperture of lobe.

7. Machine according to one of claims 1 to 6 characterized in that it comprises means which place the cylinders (310) in low pressure supply when they are at the sector (110) cam without lobe functional.

8. Machine according to one of claims 1 to 7 characterized in that the orifices (62, 64) of the cylinders (310) housing the pistons (500) provided at the neutralized sector (110) are:

. either not powered,

.be connected to a low pressure inside the crankcase,

. connected to a pressure of feeding, low pressure,

. connected to a selected low specific pressure,

to avoid biasing the pistons (500) radially outwardly at the neutralized sector (110).

9. Machine according to one of claims 1 to 8 characterized in that it has a plane of symmetry orthogonal to an outer flat (112) of the housing.

10. Machine according to one of claims 1 to 9 characterized in that it comprises a non-regular distribution of the lobes to define a homokinetic motor.

11. Machine according to one of claims 1 to 10 characterized in that it comprises several sectors (110) devoid of functional lobe, equidistributed around the axis 0-0.

12. Machine according to one of claims 1 to 11 characterized in that it comprises two sectors (110) devoid of functional lobe diametrically opposed to the axis 0-0.

13. Machine according to one of claims 1 to 12 characterized in that it comprises two flats (112) diametrically opposite to the axis 0-0.

14. Machine according to one of claims 1 to 13 characterized in that it comprises a central shaft (40) rotatably connected with the cylinder block (30), hollow, to allow the passage of an auxiliary shaft, by example a shaft coupled to a differential and rotatably connected with a gimbal driving a wheel.