Rotor Assembly for Rotary Compressor
A traditional compressor unit of the sealed type suffers in that a failure of either the motor or the compressor require both to be discarded Provided is a compressor (1) having a rotor assembly (3) within which a rotor (24) is rotated on an eccentric shaft (28) in a sealed chamber (23) Two or more intake ports (32, 33) are provided that open into the sealed chamber (23) and two or more exhaust ports (34, 35) are provided with one way valves (38), to permit compressed gas to exit the sealed chamber (23) The geometry of the rotor (24) and sealed chamber (23) and eccentric drive (28) are such that apices of the rotor (24) remain in contact with a peripheral wall (22) of the sealed chamber (23) as the rotor (24) rotates and apex seals (36) are provided on the apices of the rotor (24) to prevent leakage of the gas around the apices of the rotor (24) In a preferred embodiment the rotor (24) is a multi-lobed rotor orbiting within a trochoidal chamber (23).
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This invention relates to rotor assemblies for rotary compressor units especially but not exclusively units for small refrigeration units such are suitable for use in small refrigerators and automotive air conditioners. Such units must be compact, quiet, reliable and economical to manufacture and operate.
BACKGROUND OF THE INVENTIONCompressor units for domestic refrigerators are commonly of the sealed unit type in which both the compressor and a motor permanently coupled to the compressor is located within an enclosure that is completely and permanently sealed except for refrigerant connections to the remainder of the refrigeration unit. Such a unit has the disadvantages that failure of either the motor or the compressor requires both to be discarded, different sealed units are required for electrical supplies requiring different motors, even though the compressor is identical, and two devices, both of which generate unwanted heat, are thermally coupled within the same enclosure.
It is known in compressor units for automotive air conditioning systems, which are engine driven, and thus require a clutch mechanism, to utilize an electromagnetic clutch between a belt driven pulley and the compressor.
In the interests of smoother and more silent compressors, there has been some adoption of scroll type compressors in compression type refrigeration units, available for example from Lennox, Copeland and EDPAC International.
An alternative form of piston compressor which has been proposed, is the rotary piston compressor using a lobed rotor in a trochoidal chamber and having some resemblance to rotary piston engines such as the Wankel engine although the operating cycle is substantially different and the shaft is driven by an external power source rather than being driven by the rotary piston. Such compressors are exemplified in U.S. Pat. Nos. 3,656,875 (Luck); 4,018,548 (Berkowitz); and 4,487,561 (Eiermann).
U.S. Pat. No. 5,310,325 (Gulyash) discloses a rotary engine using a symmetrical lobed piston moving in a trochoidal chamber on an eccentric mounted on a rotary shaft and driven through a ring gear by a similarly eccentric planet gear rotated at the same rate as the eccentric, the gear ratio of the ring gear to the planet gear being equal to the number of lobes on the rotor, typically three. The apices of the lobes trace trochoidal paths tangent to the trochoidal chamber wall thus simplifying sealing.
U.S. Pat. No. 6,520,754 (Randolphi) discloses a compressor for a refrigeration unit having a three lobed rotor orbiting in a chamber defined within a sealed casing and using a magnetic coupling outside of the casing to rotate the rotor.
SUMMARY OF THE INVENTIONThe present invention relates to a compressor having a rotor assembly within which a rotor is rotated on an eccentric shaft in a sealed chamber. Two or more intake ports are provided that open into the sealed chamber and two or more exhaust ports are provided with one way valves, to permit compressed gas to exit the sealed chamber. The geometry of the rotor and sealed chamber and eccentric drive are such that apices of the rotor remain in contact with a peripheral wall of the sealed chamber as the rotor rotates and apex seals are provided on the apices of the rotor to prevent leakage of the gas around the apices of the rotor. In a preferred embodiment the rotor is a multi-lobed rotor orbiting within a trochoidal chamber.
The features of the present invention will be apparent from the following description of a presently preferred embodiment thereof.
Referring to the
The rotor assembly 3, in the embodiment illustrated in
In the embodiment illustrated, the rotor 24 is mounted on an eccentric shaft 28 for orbital movement along a path within chamber 23. The profile of chamber 23 is an outline of the path that the tips of the lobes A, B, C of the rotor 24 follows. The ratio of the ring gear 31 to the eccentric gear 30 (or timing pinion) is equal to the number of lobes, in this case three, of the rotor 24. In the embodiment illustrated in
In order to prevent compressed gas leaking from part D, E or F of chamber 23 into one of the other parts D, E or F of chamber 23 as the rotor 24 is rotated, apex seals 36 are provided in a slot 36A in the apex A, B and C of rotor 24. In the embodiment illustrated in
The rotor assembly 53 is similar to the rotor assembly 3 shown in
In the embodiment illustrated, the rotor 64 is mounted on an eccentric shaft 68 for orbital movement along a path within chamber 63. The profile of chamber 63 is an outline of the path that the tips of the lobes of the rotor 64 follows. The ratio of the ring gear 71 to the eccentric gear or timing pinion is equal to the number of lobes, in this case three, of the rotor 64. In the embodiment illustrated in
The operation of the rotor 64 in
In order to prevent compressed gas leaking from one part of chamber 63 into another one of the other parts of chamber 63 as the rotor 24 is rotated, apex seals 76 are provided on the apices of rotor 64 as shown in
The rotor assembly 103 is similar to the rotor assembly 3 shown in
In the embodiment illustrated, the rotor is mounted on an eccentric shaft 118 for orbital movement along a path within chamber. The profile of the chamber is an outline of the path that the tips of the lobes of the rotor follow. The ratio of the ring gear to the eccentric gear or timing pinion is equal to the number of lobes, in this case three, of the rotor. In the embodiment illustrated in
The operation of the rotor in
In order to prevent compressed gas leaking from one part of chamber into another one of the other parts of chamber as the rotor is rotated, apex seals are provided on the apices of rotor.
The rotor assembly of the present invention is particularly useful in compressors in various applications including (but not limited to) consumer household, automotive air conditioners, industrial, portable, transportable, commercial, scientific, medical, environmental and military disciplines. If required, multiple rotors or multiple rotor assemblies can be provided in a compressor in accordance with present invention. A number of the advantages of the present invention over conventional compressor designs are as follows:
(a) only two major moving parts in the compressor
(b) light weight
(c) shaft driven rotor in combination with a simplified gear reduction drive
(d) apex seals on the rotor prevent loss of compression
(e) can utilize a variable speed drive
(f) can obtain variable output
It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended to limit the broader aspects of the present invention.
Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those skilled in the art, which variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.
Claims
1. A compressor comprising a rotor assembly within which a rotor is rotated on an eccentric shaft in a sealed chamber, two or more intake ports are provided that open into the sealed chamber, two or more exhaust ports are provided with one way valves, to permit compressed gas to exit the sealed chamber, the geometry of the rotor and sealed chamber and eccentric drive are such that apices of the rotor remain in contact with a peripheral wall of the sealed chamber as the rotor rotates and apex seals are provided on the apices of the rotor to prevent leakage of the gas around the apices of the rotor.
2. The compressor of claim 1, wherein the rotor is a multi-lobed rotor orbiting within a trochoidal chamber.
3. The compressor of claim 2, wherein the rotor is a three lobed rotor journalled on a shaft and having a ring gear driven by timing pinion, the gear ratio of the ring gear to the timing pinion being three to one.
4. The compressor of claim 1, wherein the apex seals are compression seals that remain in contact with the peripheral wall of the sealed chamber as the rotor rotates.
5. The compressor of claim 4, wherein the apex seals have an apex seal spring to maintain the apex seal in contact with the peripheral wall of the sealed chamber as the rotor rotates.
6. The compressor of claim 1, wherein the rotor assembly comprises a back plate, rotor housing and front plate wherein an inner peripheral wall of the rotor housing together with inner surfaces of the back plate and front plate define the sealed chamber within which the rotor is rotated on an eccentric shaft.
7. The compressor of claim 6, comprising a pair of intake ports that open into the sealed chamber and a pair of exhaust ports provided in the rotor housing with one way valves, to permit compressed gas to exit the sealed chamber as the rotor rotates.
8. The compressor of claim 7, wherein the pair of intake ports are provided in the back plate.
9. The compressor of claim 7, wherein the pair of intake ports are provided in the front plate.
10. The compressor of claim 6, comprising one or more intake ports in the back plate and one or more intake ports in the front plate, all of said intake ports opening into the sealed chamber and a pair of exhaust ports provided in the rotor housing with one way valves, to permit compressed gas to exit the sealed chamber as the rotor rotates.
11. The compressor of claim 1, comprising a rotary drive enclosed by a sealed casing and orbiting the rotor, a driven element of a magnetic coupling in driving connection with the rotary drive and orbiting the rotor, the driven element enclosed by the sealed casing and including at least one magnet, a driving element of the magnetic coupling outside of the casing in close proximity to the driven element, and an arrangement for rotating the driving element.
12. The compressor of claim 11, wherein the arrangement for rotating the driving element includes an electric motor.
13. The compressor of claim 12, wherein the magnet includes a plurality of electromagnets.
14. The compressor of claim 13, wherein the driving element includes a plurality of electromagnets.
15. The compressor of claim 1, comprising a rear vector plate to cap the back of the rotor assembly.
16. The compressor of claim 15, comprising a seal retention plate to cap the front of the rotor assembly, and comprising an opening through which the shaft extends to permit an end of the shaft to be connected to a direct drive.
17. The compressor of claim 16, comprising a seal around that portion of the shaft passing through the opening in the seal retention plate.
Type: Application
Filed: Jul 23, 2008
Publication Date: Oct 27, 2011
Applicant: Randell Technologies Inc. (Bolton, ON)
Inventors: Darryl Fleger (Lefroy), David Robert Gibbs (Aurora)
Application Number: 12/990,115
International Classification: F01C 1/02 (20060101);