Claims:We Claim:

1. A supercharger (100), comprising at least:

a housing defining (102) a pumping chamber (103) and an oil chamber (104) attached to said pumping chamber (103), said pumping chamber (103) and said oil chamber (104) being isolated from each other in a manner such that oil from said oil chamber does not enter the pumping chamber (103);

a shaft (106) extending across said pumping chamber (103) and said oil chamber(104), said shaft (106) adapted to isolate said pumping chamber (103) from said oil chamber (104);

at least one sealing element (108) located at the interface of the pumping chamber (103) and said shaft (106) extending into said pumping chamber;
and

at least one sealing element (109) located at the interface of the oil chamber (104) and said shaft (106) extending into said oil chamber (104).

2. The supercharger of claim 1, wherein said shaft has varying diameter.

3. The supercharger of claim 1, wherein part of said shaft with smaller diameter extends across said pumping chamber.

4. The supercharger of claim 1, wherein part of said shaft with larger diameter extends across said oil chamber.

5. A supercharger (100), comprising at least:

a housing (102) defining a pumping chamber (103);

an oil chamber (104) attached to said pumping chamber 103;

a shaft (106), at least a part of said shaft (106) extends across said pumping chamber 103 and said oil chamber (104);

at least one sealing element (108) located at the interface of the pumping chamber (103) and said shaft (106) extending into said pumping chamber;

at least one sealing element (109) located at the interface of the oil chamber (104) and said shaft (106) extending into said oil chamber (104);

a first wheel (110) mounted on said shaft (106), and located in said oil chamber (104), said first wheel (110) in engagement with a transmission element (113); and

said transmission element (113) engages with and drives a first end of a link element (114) in a manner such that a second end of link element (114) maintains predefined gap with respect to a second wheel (116) located in said pumping chamber (103).

6. The supercharger (100) of claim 5, wherein said first wheel (110) is eccentrically mounted on said shaft (106).

7. The supercharger (100) of claim 5, wherein said second wheel (116) is eccentrically mounted on said shaft 106.

8. The supercharger (100) of claim 5, wherein the eccentricity of first wheel (110) with respect to said shaft (106) is equal to eccentricity of said second wheel (116) with respect to said shaft (106).

9. The supercharger (100) of claim 5, wherein said transmission element (113) comprises a roller element (111) and a piston (112). , Description:Field of the invention
[0001] This invention relates to the field of superchargers.

Background of the invention
[0002] The use of rotary piston compressors in superchargers are well known in the art. These compressors make use of a reciprocating action of the piston to drive a ring member within the housing of the compressor. The rotating piston compressor, comprises a wheel rotating within the housing, with the help of a shaft and a reciprocating piston. Two sets of valves take care of the air intake and exhaust. The intake valve receives air into the rotating piston compressor, while the exhaust valve delivers compressed air to the inlet of the engine. The movement of the piston, ensures that the wheel compresses and delivers the air to the outlet. The piston may be oil lubricated, and the air that is compressed needs to be free from oil. The movement of the wheel within the housing with respect to the piston, creates an area within the housing for sucking and compressing the air. At higher speeds of movement of the ring member, the contact between the ring member and the piston will be critical. The contact may require lubrication. However, the oil that is used for lubrication will mix with the air that needs to be compressed resulting in contamination. Hence, there is a need to prevent mixing of oil and air, and also ensure a contact free operation between the wheel and the piston.

[0003] Prior art patent application JP2012062781 discloses a supercharger used for compressing air for internal combustion engine of vehicle. The supercharger has a seal portion which is press-contacted so that sliding of a seal ring provided in a shaft to which a turbine impeller is connected. The shaft is surrounded by a turbine housing. A lubricate oil supply space is arranged opposite to the turbine impeller that is adjacent to the seal portion. An annular flange portion shields the lubricate oil ejected toward the seal portion, while arranging to the lubricate oil supply space. The annular flange portion is attached to the surrounding surface of the shaft. Since the lubricating oil ejected toward the seal portion is shielded by the annular flange, the spraying of the lubricating oil directly with respect to seal part can be prevented. Thus the leaking of the lubricating oil out of the seal portion can be avoided.

Brief description of the accompanying drawing
[0004] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:

[0005] FIG. 1 illustrates a supercharger.

Detailed description of the embodiments
[0006] FIG. 1 illustrates a supercharger. The supercharger 100 comprises at least a housing 102 defining a pumping chamber 103 and an oil chamber 104 is attached to the pumping chamber 103. The pumping chamber 103 and the oil chamber 104 being isolated from each other in a manner such that oil from the oil chamber 104 does not enter the pumping chamber 103. A shaft 106 extends across the pumping chamber 103 and the oil chamber 104, the shaft 106 is adapted to isolate the pumping chamber 103 from the oil chamber 104. The shaft 106 has varying diameter. The part of the shaft 106 with smaller diameter extends across the pumping chamber 103. The part of the shaft 106 with larger diameter extends across the oil chamber 104. At least one sealing element 108 is located at the interface of the pumping chamber 103 and the shaft 106 extending into the pumping chamber 103, and at least one sealing element 109 is located at the interface of the oil chamber 104 and the shaft 106 extending into the oil chamber 104. The varying diameter of the shaft and the sealing element (108 and 109) present in the pumping chamber and the oil chamber respectively, together ensure that the oil form the oil chamber 104 does not flow and get mixed with air present in the pumping chamber 103. In addition to the above mentioned function of preventing mixing of oil and air, the proposed supercharger also enables a contact free operation between a piston and a wheel present in the pumping chamber 103 of the supercharger 100. The same will be explained in further detail.

[0007] As mentioned above, the supercharger 100 comprises at least a housing 102 defining a pumping chamber 103. An oil chamber 104 is attached to the pumping chamber 103. A shaft 106 extends across the pumping chamber 103 and the oil chamber 104. At least one sealing element 108 is located at the interface of the pumping chamber 103 and the shaft 106 extending into the pumping chamber, and at least one sealing element 109 is located at the interface of the oil chamber (104) and the shaft 106 extending into the oil chamber 104. A first wheel 110 is mounted on the shaft 106, and located in the oil chamber 104, the first wheel 110 is in engagement with a transmission element 113. The first wheel (110) is eccentrically mounted on the shaft (106).The transmission element 113 comprises a roller element 111 and a piston 112. The piston 112 may be spring loaded. The transmission element 113 engages with and drives a first end of a link element 114 in a manner such that a second end of link element 114 maintains predefined gap with respect to a second wheel 116 located in the pumping chamber 103. The second wheel 116 is eccentrically mounted on said shaft 106. The eccentricity of first wheel 110 with respect to the shaft 106 is equal to eccentricity of the second wheel 116 with respect to the shaft 106.

[0008] The shaft 106 is inserted in the pumping chamber 103 and the oil chamber 104 through a bore in the pumping chamber 103 and a bore in the oil chamber104. The shaft 106 is held with the help of bearings in both the pumping chamber 103 and the oil chamber 104. The first wheel 110 and the second wheel 116 are mounted on to the shaft 106. The eccentricity of the first wheel 110 and the second wheel 116 is equal so that the gap is always maintained between the link element 114 and the second wheel 116. The first wheel is in engagement with a transmission element 113. The transmission element comprises a roller element 111 and the piston 112. The roller element 111 is capable of receiving the rotational movement of the first wheel 110 and transfer the rotational movement into a reciprocating motion of the piston 112. The movement of the piston is perpendicular to the axis of the shaft 106. The link element 114 is connected to the piston 112 through the first end, the axis of the link element 114 being perpendicular to the axis of the piston 112. Alternately, the link element 114 and the piston 112 can be made integrated. At least a part of the second end of the link element 114 is located in the pumping chamber 103. As the piston 112 reciprocates, the link element 114 moves towards and away from the housing 102 and the oil chamber 104. The second end of link element 114 maintains predefined gap with respect to a second wheel 116 located in said pumping chamber 103. The working of the supercharger 100 will now be explained. The supercharger 100 is driven by the engine crankshaft. As the shaft 106 rotates, the first wheel 110 and the second wheel 116 that is mounted on the shaft 106 also rotates. The first wheel 110 rotates within the oil chamber 104 and the second wheel 116 rotates within the pumping chamber 103. The first wheel 110 drives a transmission element 113.The transmission element 113 comprises a roller element 111 and a piston 112. The link element 114 that is connected to the piston 112 (through the first end), follows the movement of the piston 112. That is, as the piston 112 moves away from the housing 102, the link element 116 also moves away from the housing 102. Also, as the piston 112 moves towards the housing 102, by the action of the spring, the link element 114 also moves towards the housing 102. At least a part of the second end of the link element 114 is located in the pumping chamber 103, and maintains a predefined gap with respect to a second wheel 116. Throughout the operation of the second wheel 116 in the pumping chamber 103, the gap between the second end of the link element 114 and second wheel 116 is maintained. The geometry of the link element 114, the length of traverse of piston 112 and the eccentricity of the first wheel 110 and the second wheel 116, ensures that the second end of the link element 114 does not come into contact with the second wheel 116 located in the pumping chamber 103. Moreover, the profile of the link element 114 ensures that only the axial component of force received from the first wheel 110 through the transmission element 113 reaches the second end of the link element 114. This ensures that the effect any imbalance or eccentric force is nullified and does not cause instability in the link element 114.

[0009] The above mentioned supercharger 100 can also use a shaft 106 that is of uniform diameter. In such a case, a groove is formed on the shaft, a ring and/ or a collar element is then fitted in the groove. The assembly of shaft with ring and/ or collar is then inserted at the interface where the shaft opens into the gap in between the pumping chamber 103 and the oil chamber 104. The ring and or the collar that is fitted onto the groove, enables a shaft of uniform diameter to function like a stepped shaft. In general a shaft 106 of having a geometry different from a stepped shaft, but can be converted into a steeped shaft 106 by using accessories can be used in the proposed supercharger 100.

[00010] With the use of the above mentioned supercharger 100, the pumping chamber 103 and the oil chamber 104 can be separated, and mixing of oil with air in the pumping chamber 103 can be avoided with the use of sealing element 108 and sealing element 109 that prevents the oil from moving from the oil chamber 103 towards the pumping chamber 103. Also, by maintaining a gap between the link element 114 and the second wheel, a contact free operation can be achieved, thereby preventing wear and tear of the second wheel 116.

[00011] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention in terms of the type of supercharger, type of actuation mechanism used in the piston, and the profile of the shaft. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.