ROTARY PISTON AND CYLINDER DEVICE

Abstract

A rotary piston and cylinder device (1) comprising: a rotor (2), comprising a rotor surface (2a), a piston (5) which extends from the rotor surface, a stator (4), a rotatable shutter (3), the rotor surface and the stator together defining an annular chamber, and the piston arranged to rotate, through the annular chamber, wherein when the chamber is viewed in axial cross-section, substantially a single surface of the stator in part defines the chamber (100).

Claims

1. A rotary piston and cylinder device comprising: a rotor, comprising a rotor surface, a piston which extends from the rotor surface, a stator, a rotatable shutter, the rotor surface and the stator together defining an annular chamber, and the piston arranged to rotate, through the annular chamber, wherein when the chamber is viewed in axial cross-section, substantially a single surface of the stator in part defines the chamber.

2. A device as claimed in claim 1 in which the chamber-defining stator surface is a major surface of the stator which defines the chamber.

3. A device as claimed in claim 1 in which the stator surface when viewed in axial cross-section is substantially linear.

4. A device as claimed in claim 1 in which the stator surface is substantially cylindrical.

5. A device as claimed in claim 1 in which the stator surface is radially outward of the chamber-defining rotor surface.

6. A device as claimed in claim 1 in which the rotor surface is of substantially diablo shape/configuration.

7. A device as claimed in claim 1 in which the rotor surface is substantially symmetrical with respect to a plane which extends through a mid-region of the rotor surface, and which plane is perpendicular to the axis of rotation of the rotor

8. A device as claimed in claim 1 in which the rotor surface is inclined, such that the orientation of the rotor surface may be viewed as being angularly offset from a plane which is perpendicular to the axis of rotation of the rotor.

9. A device as claimed in claim 1 in which the rotor surface is of generally flared profile, when viewed in axial cross-section, and the rotor surface extends between a first rotor surface end region and a second rotor surface end region, and the first rotor surface end region being spaced along the axis of rotation of the rotor with respect to the second rotor surface end region, and one of the rotor surface end regions having a greater radial extent than the other end region, or each of the end regions may have substantially the same radial extent.

10. A device as claimed in claim 1 in which the rotor surface and the rotor surface extends between a first rotor surface end region and a second rotor surface end region, and the first rotor surface end region being spaced along the axis of rotation of the rotor with respect to the second rotor surface end region, or each of the end regions may have substantially the same radial extent, and both end regions being of is of generally flared profile, when viewed in axial cross-section.

11. A device as claimed in claim 1 in which the rotor surface is provided with one or more ports to allow communication of fluid between the annular chamber and a space external of the chamber.

12. A device as claimed in claim 11 in which the port or ports comprise an opening which extends through to an opening in a rearward surface of the rotor surface which in part defines the working chamber.

13. A device as claimed in claim 12 in which the rearward surface is spaced from the rotor surface, in a direction generally along the axis of rotation.

14. A device as claimed in claim 11 in which the port is in communication with the working chamber exits a portion of face of the rotor that is axially spaced from the rotor surface.

15. A device as claimed in claim 14 in which the port is arranged to provide a working fluid porting to or from the annular chamber through the rotor surface.

16. A device as claimed in claim 1 in which the chamber is substantially defined, when viewed in cross-section by a plane including the axis of rotation, by two major surfaces, the single surface of the stator and a surface of the rotor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Various embodiments of the invention will now be described, by way of example only, with reference to the following drawings in which:

[0051] FIG. 1 is an axial cross-section of a rotary piston and cylinder device,

[0052] FIG. 2 is a perspective view of the rotary piston and cylinder device of FIG. 1,

[0053] FIG. 3 is perspective view of a rotor of the device of FIG. 1,

[0054] FIG. 3a is a perspective view of the rotor of FIG. 3,

[0055] FIG. 4 is a cross-sectional perspective view of a variant embodiment to that shown in FIG. 1, and

[0056] FIG. 5 is a further variant embodiment of a rotary piston and cylinder device.

DETAILED DESCRIPTION

[0057] Reference is made to the Figures which show a rotary piston and cylinder device 1 which comprises a rotor 2, a stator 4, and a shutter disc 3. The stator comprises a formation, such as a housing or casing, which is maintained relative to the rotor, and an internal surface of the stator facing a surface 2a of the rotor, together define an annular space or working chamber, shown generally at 100. The stator 4 may comprise two or more parts, which together substantially enclose the rotor and shutter therebetween.

[0058] Integral with the rotor and extending from the surface 2a there is provided a piston 5. A slot or opening 3a provided in the shutter disc 3 is sized and shaped to allow passage of the piston therethrough. Rotation of the shutter disc 3 is arranged to ensure that the timing of the shutter remains in synchrony with the rotor by a suitable transmission.

[0059] A transmission assembly, not illustrated, can rotationally connect and synchronise the rotation of the shutter to the rotor. The transmission assembly may include a multiple toothed gears or another transmission type. The shutter disc 3 is rotationally mounted by way of a shaft portion 7.

[0060] In use of the device, a circumferential surface 30 of the shutter disc faces the surface 2a of the rotor so as to provide a seal therebetween, and so enable the shutter disc to functionally serve as a partition within the annular cylinder space.

[0061] The geometry of the interior (i.e. facing into and in part defining the chamber) surface 2a of the rotor is governed by the part of the circumferential surface 30 of the rotating shutter disc.

[0062] The rotor and the stator are configured to provide the annular cylinder space with one or more inlet port/s and one or more outlet port/s for the working fluid, as described in further detail below.

[0063] The rotor 2 is located intermediate of distal end portions of the shaft 9. Depending on how the device 1 is used, in terms of its operational application, the shaft may be used to provide rotational input or output.

[0064] As is evident, since the piston 5 is of relatively wide dimension, the opening 3a of the shutter 3 must be accordingly proportioned, in order to allow the piston to pass through the opening. It will be appreciated, and is to some extent evident in the drawings, that the boundary of the opening 3a has to be suitably configured/profiled to take account of the relative movement between the piston and the shutter disc.

[0065] The rotor 2 is provided with multiple ports 10 which extend from the surface 2a through to the opposite, or what could be termed outward, surface of the rotor. As will be described further below, this conveniently allows for fluid to be transferred to or from the annular or working chamber of the device. This may be for example compressed fluid.

[0066] Depending from the stator 4, there is provided a formation 15, which in this example may be described as a spigot. This feature provides a port, such as an outlet port, for working fluid from the device. The formation 15 comprises a passageway 16 with an opening 16a, and the opposite end of the passageway 16 is provided with an opening 16b. The ports 10 of the rotor are arranged to periodically come into register with the opening 16b of the stator. It will be appreciated that the view in FIG. 1 shows a port 10 in alignment with the port 16b

[0067] This means that as the rotor 2 rotates and the port 10 comes into alignment with the opening 16b, and passage 16 is opened through which fluid can flow into and/or out of the annular chamber 100.

[0068] During assembly or manufacture of the device 1, the component parts of the stator, can be rigidly attached together by way of fasteners or by some other way.

[0069] The chamber 100 is also defined by an internal (i.e. facing into the chamber) surface 4a. Save for the presence of a port 14 (shown in FIG. 2), the surface 4a is substantially cylindrical shape. This means, as seen in (axial) cross-section of the chamber the surface 4a presents a single, major linear boundary to the chamber. In essence the chamber 100 (when considered in cross-section of a plane incorporating the axis of rotation of the rotor) is substantially defined by two major surfaces/sides (i.e. the rotor surface 2a and the stator surface 4a), and what may be termed a two-sided chamber.

[0070] The rotor surface 2a is of substantially concave cross-section, and when considered as a whole can be viewed as presenting the surface of a diablo.

[0071] The shaft 9 being rotatably mounted by bearings 20 is arranged to rotate about an axis A-A.

[0072] The port 14 can provide an inlet for working fluid. If the device 1 is used as a compressor, a suitable motive or drive source can be attached to the shaft 9 or to the shaft 7 of the shutter or to another part of the transmission.

[0073] The surface 2a of the rotor 2 may be described as being substantially symmetric about the axis of rotation of the rotor. This can be better understood with reference to the plane Y-Y, which extends through the midpoint 24 of the rotor surface 2a, and which is perpendicular to the axis of rotation A-A. About this plane, the rotor surface is substantially symmetrical. Put an alternative way, the general orientation/direction of the rotor surface 2a is directed substantially perpendicularly to the axis of rotation A-A.

[0074] In FIG. 4 a modified version 40 of the device 1 is shown in which an extended shaft 9 is provided with two bearings 20, in essence both being located to one side of the chamber 100. The arrangement of a passageway 16 extends along the stator 4.

[0075] Such an arrangement can allow a larger cross-section of passageway 16 than otherwise possible, since all the shaft and bearings are located towards the other side of the chamber.

[0076] Reference is made to FIG. 5 which shows a further embodiment 50 in which the rotor surface is orientated at an incline relative to the axis of rotation of the rotor 2, as schematically illustrated by the headed broken line. This results in the requirement that the single major surface 104a of the stator which defines in part the chamber is of substantially frusto-conical shape. A surface 102a of the rotor co-defines the chamber with the surface 104a of the stator 4.

[0077] Some of the geometrical characteristics of the outward, inclined orientation of the device 50 are now discussed. FIG. 5 serves to illustrate the geometric characteristic of the rotor 2 of the device 50. The rotor surface 102a may be described as being orientated an incline relative to the axis of rotation A-A.

[0078] The inclined, outward, orientation of the rotor surface 102a can be described, by extrapolating the surface 102a, which in essence extends between the distal end regions of the rotor surface 102a, towards the axis of rotation of A-A. That line can then be extended to intercept the axis A-A, at a particular angle of incline x.