Title:
Modular Design of Swash plate type Compressors for all automotive air-conditioning applications
Field of Invention:
This invention relates to the design method and system of an innovative Modular Design of Swash plate type Compressors which have the innovative features of using standard parts across the wide range of applications with only few change parts for the cooling capacity range from 1 kW to 50 kW which can be used for all Air Conditioning applications like Car air-conditioning, Bus air-conditioning, Rail coaches Air-Conditioning and truck refrigeration units for transport of refrigerated goods.
Background of the invention: General Scenario:
Compressors are used for sucking the low pressure super heated (any type of refrigerants, HFC (Hydrofluoro Carbon) , HFO (hydrofluoro-olefin), NH3, C02 and etc.,) refrigerant gas from Evaporator (through Internal Heat Exchanger (IHX) if it is connected in the circuit), compressing to high pressure and discharging the compressed refrigerant gas at high temperature to Condenser for de-superheating, Condensing and sub-cooling the refrigerant medium in the vapour compression Refrigeration systems used in the chemical industry, Process industry, Air Conditioning applications, Power generation units and many other applications. Though our disclosed invention put forward by the current patent application may find a number of other embodiments, we are presenting the invention through an embodiment especially applicable to the automotive Air Conditioning systems having Modular Design of Swash plate type Compressors which have the innovative features of using standard parts across the wide range of applications with only few change parts for the applications like Car air-conditioning, Bus air-conditioning, Rail coaches Air-Conditioning and truck refrigeration units for transport of refrigerated goods.
Automotive sector has been growing at a fast pace and due to tighter environment norms and steep competition the quest for efficiency increment, compactness, light weight and lower cost, higher productivity and lower lead times are increasing day by day.
Refrigerant Vapor Compression Refrigeration circuit:
The prime goal of the designers of automotive air conditioning systems is to design the compressor to deliver highest cooling capacity by consuming lowest power, which in turn will have the highest COP. At the same, in order to make the design feasible for manufacturing under mass production, the designer must focus to design the series of compressor models having majority of the parts in common but minimum change parts to make the capital investment lower and productivity higher to achieve the lowest cost of complete product.
Problem Statement
There exists a need of a high efficient compressor which must be compact, light weight and low cost to provide higher COP for the rated cooling capacity. The present invention addresses such a need. More particularly, the invention relates to devices and methods employing Swash plate type Refrigeration Compressors with modular design Methodology, have the innovative features of using standard parts across the wide range of applications with only few change parts by which family of Compressors can be designed and produced, with great improvements in terms of compactness, light weight and lower cost, higher productivity and lower lead times
Prior Art
The U.S. Patent no. 1,409,057 dated Mar 7, 1922 by A.G.M. MICHELL disclosed the invention related to Mechanism for the Inter-conversion of Reciprocating and Rotary Motion in general, and specifically to double sided Piston and Swash plate of plain taper surface with Shoe having Spherical surface to mesh with Piston pocket and plain surface to mate with Swash plate.
The US Patent no. US3750848 dated Feb 11, 1975 by Nakayama et al. disclosed the invention related to an improved swash plate compressor provided with a pair of cylinder blocks comprising an aluminium block portion cast with filler provided with a plurality of sleeves connected to each other with connecting member. Modular design concept is not written.
The US Patent no. US5768974 dated Jun 23, 1998 by Ikeda et al. disclosed the invention related to Swash plate type Compressor includes an improved thrust bearing for axially supporting the swash plate, the bearing is of Composite type. Modular design concept is not written.
The US Patent no. US 5596920 dated Jan 28, 1997 by Umemura et al. disclosed the invention related to compressor includes a drive shaft supported on cylinder block, a swash plate rotates in accordance with rotation of the drive shaft. A plurality of pistons reciprocate in the associated bores in the cylinder block in accordance with the rotation of the swash plate. First an second thrust bearings are provided in the cylinder block at both sides of the swash plate, and receive the axial loads applied to the swash plate and drive shaft according to the reciprocation of the pistons. Modular design concept is not written.
The U.S. Patent application no. US20050061143 dated Mar 24 2005 by Koelzer, Germany disclosed the invention related to Modular Swash plate Compressor, which is of having housing includes a cylinder block with plurality of Piston channels, swash plate coupled to drive shaft. The housing is mounted to a mounting flange selected from a plurality of mounting flanges, each of which is designed for a different type of vehicle and all of which can be fastened to the housing. This invention is related to modular design of compressor in terms of mountability of compressor for different vehicle not related to the displacement Modularity of the compressor models.
The Indian Patent application No. 1475/DEL/2012 dated 14th May 2012, by Selvaraji Muthu et al. disclosed that Swash plate type Refrigeration Compressors with Convergent conical shape Pistons and matching Cylinder bores.
The Indian Patent application No. 1476/DEL/2012 dated 14th May 2012, by Selvaraji Muthu et al. disclosed that Swash plate type Refrigeration Compressors with Composite Pistons made up of composite materials partially using metallic materials (Aluminium, Cast-iron, Steel) etc..) by casting, forging, machining and the rest with either of Non-metallic materials like PTFE, PEEK, PPS through injection molding process.
The Indian Patent application NO.1831/DEL/2012 dated 14th June 2012, by Selvaraji Muthu et al. disclosed that Swash plate type Refrigeration Compressors with double headed Labyrinth Pistons for Automotive Air-conditioning applications.
The Indian Patent application No. 1832/DEL/2012 dated 14th June 2012, by Selvaraji Muthu et al. disclosed that Swash plate type Refrigeration Compressors with Composite housings with ease of manufacturing for Automotive Air-conditioning applications.
(Table Removed)
Disadvantages of prior art:-
1. Boundary volume of the compressor is high for the rated cooling capacity
2. Overall weight of the compressor is high for the rated cooling capacity
3. Cost is high due to bigger size and higher weight
4. Higher frictional power loss due to surface contact of Shoe, hence lower COP
5. Contributing to more global warming
SUMMARY OF THE INVENTION:
The swash plate type Refrigeration Compressor for Automotive and refrigeration applications is consists of multiple single or double headed Pistons with shoes, mating Cylinder blocks, Swash plate which is press-fitted on the drive shaft, set of radial and thrust bearings to support the shaft and Swash assembly and to transmit the radial and thrust load to the stationary housings.
The Piston is having spherical pocket for mating with hemi-spherical shoe, which slides on the swash surface to transmit the load.
The set of Reed type Suction and Discharge valves with Valve plate are assembled on the cylinder block and housed in the front head and rear head covers.
The Front head cover has provisions to assemble the radial lip seal and the stator of Electro-Magnetic Clutch. Also the radial bearing of the rotor assembly is transmitting the bending load due to belt to front head cover, hence in such a way that there is no any residual load of belt tension transmitted to the driving shaft.
The stroke, swash angle, and housing width of the base standard model are calculated using the following equations.
(Formula Removed)
The stroke, swash angle, and housing width of the nth variant of model are related using the following equations.
(Formula Removed)

The innovative modular design is made in such a way that the cylinder blocks and Pistons are same as the base standard design and the thickness of additional center spacer is calculated by using the following equation.
(Formula Removed)
For the design, which is using gasket for sealing between the cylinder blocks, Sg >0, and for the design, which is using the O-ring, δg =0
Whereas
Vo, S0, α0, Uo, are Displacement (cc), stroke (cm), swash angle and housing width (cm) of standard base model respectively.
Vn, Sn, α„, Lhn, are Displacement (cc), stroke (cm), swash angle and housing width (cm) of nth variant model respectively.
δg,δc,δr are Gasket thickness, dead clearance and thickness of suction REED respectively in cm.
D, Lp are Diameter and length of Piston respectively, cm. t is the thickness of Center Spacer, cm m is No. of Cylinders
BRIEF DESCRIPTION OF THE DRAWINGS
For a detailed description of the preferred embodiments of the invention, reference will
now be made to the accompanying drawings in which:
Figure 1 of 7 - Standard Base Model of Swash plate type Compressor
Figure 2 of 7 - Modular Design of Swash plate type Compressor upon the standard
Base Model
Figure 3 of 7 - The Swash & Shaft Assembly of standard Base Design and Modular
Design.
Figure 4 of 7 - Table 1 of 3, First Family of Modular Design of Swash plate type Compressor
Models for Car AC Application.
Figure 5 of 7 - Table 2 of 3, Second Family of Modular Design of Swash plate type
Compressor Models for Mini and Mid Bus AC Application.
Figure 6 of 7 - Table 3 of 3, Third Family of Modular Design of Swash plate type Compressor
Models for Big Bus and Airport Tarmac AC Application.
Figure 7 of 7 : Modular Design of Swash plate type Compressor Models with mountablity for
different vehicles, foot mounted, side direct mounted.
DETAILED DESCRIPTION
1. According to one aspect of the invention, swash plate type compressor with
multiple single or double headed pistons having the modular design
methodology by which family of compressor models designed with common
Cylinder blocks, covers, bearings, seals etc..., except only few change parts like
swash and shaft and additional spacer between the cylinder blocks.
2. In the case of Gasket sealing design, the center spacer is having plain ground surface on both the sides, whereas in the case of O-ring sealing design, Center spacer is having O-ring groove one side, which is same as the groove profile given in the one of the cylinder block.
3. The swash plate is interference fitted or press fitted on to the shaft, also alternatively it may be connected using spline between the Swash and shaft.
4. Reed suction and reed discharge valves are designed and sized in such a way that they are optimized to operate for the wide range of displacement of the compressors.
5. The cylinder bore is designed in such a way that the piston stroke is variable between base model to next bigger models by the concept of Modular Design.
6. The Oil pump, which is in general , can be a gear type, screw type, lobe type design, and particularly it is of Gerotor type sized to provide adequate lubricating oil quantity for the extreme operating conditions.
7. The front side cover has bore for oil seal assembly (Mechanical seal or Lip Seal type) and also has projection for assembling the Electro Magnetic Clutch parts.

Claims
What is claimed is:
1. A swash plate type Compressor for air conditioning applications in general and automotive application in particular comprising of multiple single or double headed Pistons, matching Cylindrical Bores, set of suction and discharge valves, valve plate, drive end and non-drive end covers, the Swash plate integral with the input drive shaft, set of thrust bearings and radial bearings for taking the axial and radial loads in addition to provide the axial and radial constraints to the input shaft with negligible friction, which is of modular design methodology by which family of compressor models designed with common Cylinder blocks, covers, bearings, seals etc... , except only few change parts like swash and shaft and additional spacer between the cylinder blocks.
2. The stroke, swash angle, and housing width of the base standard model are
calculated using the following equations.
(Formula Removed)
3. The stroke, swash angle, and housing width of the nth variant of model are
related using the following equations.
(Formula Removed)
4. The innovative modular design is made in such a way that the cylinder
blocks and Pistons are same as the base standard design and the thickness
of additional center spacer is calculated by using the following equation.
(Formula Removed)
5. For the design, which is using gasket for sealing between the cylinder blocks, δg>0, and for the design, which is using the O-ring, δg=0
6. In the case of Gasket sealing design, the center spacer is having plain ground surface on both the sides, whereas in the case of O-ring sealing design, Center spacer is having O-ring groove one side, which is same as the groove profile given in the one of the cylinder block.
7. The convergent conical shaped double ended Piston is disclosed in our Patent Application no. 1475/DEL/2012 dated 14Th May 2012.
8. The Composite Construction of Double ended Piston is disclosed in our Patent Application no. 1476/DEL/2012 dated 14Th May 2012.
9. The Non-metallic Material grades are disclosed in our Patent Application no. 1476/DEL/2012 dated 14™ May 2012.
10. The Double headed Labyrinth Piston is disclosed in our Patent Application no. 1831/DEL/2012 dated 14™ June 2012.
11. The Composite Construction of housings of swash plate compressor is disclosed in our Patent Application no. 1832/DEL/2012 dated 14Th June 2012.
12. The range of Piston nominal diameters covered in this embodiment are from 10 to 50mm in general and includes the specific Diameters namely 25, 28.5,29.5, 30.5, 32, 34, 36, 38.5, 40 , 42, 46, 50mm to name a few.
13. The range of ratio of length of Piston to Piston nominal diameter covered in this embodiment is from 1 to 5.
14. The cylinder bore is designed in such a way that the piston stroke is variable between base model to next bigger models by the concept of Modular Design.
15. The Oil pump, which is in general , can be a gear type, screw type, lobe type design, and particularly it is of Gerotor type, sized to provide adequate lubricating oil quantity for the extreme operating conditions for all models as per the Modular Design of Swash plate compressors.
16. The front side cover has bore for oil seal assembly (Mechanical seal or Lip Seal type) and also has projection for assembling the Electro Magnetic Clutch parts.
17. By this innovative modular design method, First family of compressor displacements is designed between 80 to 160 cc, as shown in Figure 4 of 7 (table 1 of 3) by using the equation stated in the point no.2 to no. 4.
18. By this innovative modular design method, Second family of compressor displacements is designed between 200 to 350 cc, as shown in Figure 5 of 7 (table 2 of 3) by using the equation stated in the point no.2 to no. 4.
19. By this innovative modular design method, Third family of compressor displacements is designed between 400 to 650 cc, as in Figure 6 of 7 (table 3 of 3) by using the equation stated in the point no.2 to no. 4.
20. Mounting provision is made in such a way that the compressor can be mounted as per different vehicle configuration, shown in Figure 7 of 7
21. As per this embodiment, application of modular design of Swash plate compressor includes the automotive air-conditioning (Car and Bus Segments) and refrigeration (Reefer trucks etc... ) with refrigerant types like HFC (Hydro-Fluoro Carbon) , HFO (Hydro-Fluoro-olefin), NH3, C02 and etc..) in general and specific to R134a, R404a, R407c, R410a , R1234yf, C02,Refrigerants..
Whereas
Vo, So, α0, Lh0, are Displacement (cc), stroke (cm), swash angle and housing width (cm) of standard base model respectively.
Vn, Sn, α„, Lhn, are Displacement (cc), stroke (cm), swash angle and housing width (cm) of nth variant model respectively.
δg,δc,δr are Gasket thickness, dead clearance and thickness of suction REED respectively in cm.
D, Lp are Diameter and length of Piston respectively, cm. t is the thickness of Center Spacer, cm m is No. of Cylinders