Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
  • F01C17/00—Arrangements for drive of co-operating members, e.g. for rotary piston and casing
  • F01C17/06—Arrangements for drive of co-operating members, e.g. for rotary piston and casing using cranks, universal joints or similar elements
  • F01C17/066—Arrangements for drive of co-operating members, e.g. for rotary piston and casing using cranks, universal joints or similar elements with an intermediate piece sliding along perpendicular axes, e.g. Oldham coupling
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
  • F04C18/02—Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents
  • F04C18/0207—Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents both members having co-operating elements in spiral form
  • F04C18/0215—Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents both members having co-operating elements in spiral form where only one member is moving

Definitions

• a scroll compressor is a certain type of compressor that is used to compress refrigerant for such applications as refrigeration, air conditioning, industrial cooling and freezer applications, and/or other applications where compressed fluid may be used.
• Such prior scroll compressors are known, for example, as exemplified in U.S. Patent Nos. 6,398,530 to Hasemann; 6,814,551, to Kammhoff et al.; 6,960,070 to Kammhoff et al.; and 7,112,046 to Kammhoff et al., all of which are assigned to a Bitzer entity closely related to the present assignee.
• the present disclosure pertains to improvements that can be implemented in these or other scroll compressor designs, the entire disclosures of U.S. Patent Nos. 6,398,530; 7,112,046; 6,814,551; and 6,960,070 are hereby incorporated by reference in their entireties.
• the orbiting scroll compressor body will commonly employ two slots spaced 180° apart in separate quadrants defined by the mutually perpendicular axes as for example is illustrated in FIG. 10.
• Such slots receive the two keys of the Oldham coupling guiding linear translational movement along one lateral axis.
• the slots are typically provided for through the provision of outwardly projecting ears.
• the movable scroll compressor body slots are positioned in substantial spaced relation from the respective axes so as to provide for carrying moment loads necessary to prevent relative angular movement between the movable and fixed scroll compressor bodies.
• the present invention is directed towards improvements over prior Oldham coupling configurations and scroll compressors incorporating the same.
• FIG. 1 is a cross section of a scroll compressor assembly in accordance with an embodiment of the present invention
• FIG. 2 is a partial cross section and cut-away view of an isometric drawing of an upper portion of the scroll compressor embodiment shown in FIG. 1;
• FIG. 6 is an exploded view of the movable scroll member and the Oldham key coupling used in previous embodiments;
• FIG. 7 is a top view of the movable scroll member shown with running clearances (in which the running clearances are greatly exaggerated for demonstrative purposes) and Oldham key contacts shown in accordance with an embodiment of the present invention;
• FIGS. 8 and 9 are illustrations similar to FIG. 7 except showing a symmetrical Oldham key placement (again with exaggerated running clearances shown) to illustrate that some unwanted rotation of the scroll and edge loading of key surfaces could otherwise occur without the non-symmetrical key contact surfaces of FIG. 7;
• FIG. 10 is a top view of a movable scroll member using a more conventional two slot arrangement for receiving two keys of an Oldham coupling.
• FIG. 10 An embodiment of the present invention is illustrated in the figures as a scroll compressor assembly 10 generally including an outer housing 12 in which a scroll compressor 14 can be driven by a drive unit 16.
• the scroll compressor assembly may be arranged in a refrigerant circuit for refrigeration, industrial cooling, freezing, air conditioning or other appropriate applications where compressed fluid is desired.
• Appropriate connection ports provide for connection to a refrigeration circuit and include a refrigerant inlet port 18 and a refrigerant outlet port 20 extending through the outer housing 12.
• the scroll compressor assembly 10 is operable through operation of the drive unit 16 to operate the scroll compressor 14 and thereby compress an appropriate refrigerant or other fluid that enters the refrigerant inlet port 18 and exits the refrigerant outlet port 20 in a compressed high pressure state.
• the outer housing 12 may take many forms.
• the outer housing includes multiple shell sections and preferably three shell sections to include a central cylindrical housing section 24, a top end housing section 26 and a bottom end housing section 28.
• the housing sections 24, 26, 28 are formed of appropriate sheet steel and welded together to make a permanent outer housing 12 enclosure.
• other housing provisions can be made that can include metal castings or machined components.
• bottom side wall region 34 of the bottom end housing section 28 telescopically interf ⁇ ts with the central housing section 24 (but is shown as being installed into the interior rather than the exterior of the central housing section 24) and is exteriorly welded by a circular weld region.
• the lower bearing member 44 in turn supports the cylindrical motor housing 48 by virtue of a circular seat 66 formed on a plate-like ledge region 68 of the lower bearing member 44 that projects outward along the top of the central hub 58.
• the support arms 62 also preferably are closely toleranced relative to the inner diameter of the central housing section. The arms 62 may engage with the inner diameter surface of the central housing section 24 to centrally locate the lower bearing member 44 and thereby maintain position of the central axis 54. This can be by way of an interference and press-fit support arrangement between the lower bearing member 44 and the outer housing 12 (See e.g. FIG. 4).
• the drive shaft 46 is formed with a plurality of progressively smaller diameter sections 46a - 46d which are aligned concentric with the central axis 54.
• the smallest diameter section 46d is journaled for rotation within the lower bearing member 44 with the next smallest section 46c providing a step 72 for axial support of the drive shaft 46 upon the lower bearing member 44.
• the largest section 46a is journaled for rotation within the upper bearing member 42.
• the upper bearing member 42 includes a central bearing hub 84 into which the largest section 46a of the drive shaft 46 is journaled for rotation. Extending outward from the bearing hub 84 is a support web 86 that merges into an outer peripheral support rim 88. Provided along the support web 86 is an annular stepped seating surface 90 which may have an interference and press-fit with the top end of the cylindrical motor housing 48 to thereby provide for axial and radial location. The motor housing 48 may also be fastened with screws to the upper bearing member 42.
• the outer peripheral support rim 88 also may include an outer annular stepped seating surface 92 which may have an interference and press-fit with the outer housing 12.
• the outer peripheral rim 88 can engage the seating surface 92 axially, that is it engages on a lateral plane perpendicular to axis 54 and not through a diameter.
• a diametric fit just below the surface 92 between the central housing section 24 and the support rim 88.
• internal circular step 94 is located axially and radially with the outer annular step 92 of the upper bearing member 42.
• the upper bearing member 42 also provides axial thrust support to the movable scroll member through a bearing support via an axial thrust surface 96. While this may be integrally provided by a single unitary component, it is shown as being provided by a separate collar member 98 that is interfit with the upper portion of the upper bearing member 42 along stepped annular interface 100.
• the collar member 98 defines a central opening 102 that is a size large enough to provide for receipt of the eccentric offset drive section 74 and allow for orbital eccentric movement thereof that is provided within a receiving portion of the movable scroll compressor member 112.
• first and second scroll compressor bodies which preferably include a stationary fixed scroll compressor body 110 and a movable scroll compressor body 112.
• the moveable scroll compressor body 112 is arranged for orbital movement relative to the fixed scroll compressor body 110 for the purpose of compressing refrigerant.
• the fixed scroll compressor body includes a first rib 114 projecting axially from a plate-like base 116 and is designed in the form of a spiral.
• the second movable scroll compressor body 112 includes a second scroll rib 118 projecting axially from a plate-like base 120 and is in the design form of a similar spiral.
• the guiding movement of the scroll compressor can be seen.
• an appropriate key coupling 140 may be provided. Keyed couplings are often referred to in the scroll compressor art as an "Oldham Coupling.”
• the key coupling 140 includes an outer ring body 142 and includes two first keys 144 that are linearly spaced along a first lateral axis 146 and that slide closely and linearly within two respective keyway tracks 148 that are linearly spaced and aligned along the first axis 146 as well.
• the key way tracks 148 are defined by the stationary fixed scroll compressor body 110 such that the linear movement of the key coupling 140 along the first lateral axis 146 is a linear movement relative to the outer housing 12 and perpendicular to the central axis 54.
• the keys can comprise slots, grooves or, as shown, projections which project from the ring body 142 of the key coupling 140. This control of movement over the first lateral axis 146 guides part of the overall orbital path of the moveable scroll compressor body 112.
• the key coupling includes four second keys 152 in which opposed pairs of the second keys 152 are linearly aligned substantially parallel relative to a second traverse lateral axis 154 that is perpendicular to the first lateral axis 146.
• the guide portions 156 linearly engage and are guided for linear movement along the second traverse lateral axis by virtue of sliding linear guiding movement of the guide portions 156 along sets of the second keys 152.
• the moveable scroll compressor body 112 has movement restrained relative to the fixed scroll compressor body 110 along the first lateral axis 146 and second traverse lateral axis 154. This results in the prevention of any relative rotation of the moveable scroll body as it allows only translational motion. More particularly, the fixed scroll compressor body 110 limits motion of the key coupling 140 to linear movement along the first lateral axis 146; and in turn, the key coupling 140 when moving along the first lateral axis 146 carries the moveable scroll 112 along the first lateral axis 146 therewith.
• the fixed scroll compressor body 110 is fixed to the upper bearing member 42 by an extension extending axially and vertically therebetween and around the outside of the moveable scroll compressor body 112.
• the fixed scroll compressor body 110 includes a plurality of axially projecting legs 158 (see FIG. 2) projecting on the same side as the scroll rib from the base 116. These legs 158 engage and are seated against the top side of the upper bearing member 42.
• bolts 160 (FIG. 2) are provided to fasten the fixed scroll compressor body 110 to the upper bearing member 42.
• the outer periphery of the fixed scroll compressor body includes a cylindrical surface 162 that is closely received against the inner cylindrical surface of the outer housing 10 and more particularly the top end housing section 26.
• a clearance gap between surface 162 and side wall 32 serves to permit assembly of upper housing 26 over the compressor assembly and subsequently to contain the o-ring seal 164.
• An O-ring seal 164 seals the region between the cylindrical locating surface 162 and the outer housing 112 to prevent a leak path from compressed high pressure fluid to the uncompressed section/sump region inside of the outer housing 12.
• the seal 164 can be retained in a radially outward facing annular groove 166.
• the upper side (e.g. the side opposite the scroll rib) of the fixed scroll 110 supports a floatable baffle member 170.
• the upper side of the fixed scroll compressor body 110 includes an annular and more specifically cylindrical inner hub region 172 and an outwardly spaced peripheral rim 174 which are connected by radially extending disc region 176 of the base 116. Between the hub 172 and the rim 174 is provided an annular piston-like chamber 178 into which the baffle member 170 is received.
• the combination of the baffle member 170 and the fixed scroll compressor body 110 serve to separate a high pressure chamber 180 from lower pressure regions within the housing 10. While the baffle member 170 is shown as engaging and constrained radially within the outer peripheral rim 174 of the fixed scroll compressor body 110, the baffle member 170 could alternatively be cylindrically located against the inner surface of the outer housing 12 directly.
• the baffle member 170 includes an inner hub region 184, a disc region 186 and an outer peripheral rim region 188.
• a plurality of radially extending ribs 190 extending along the top side of the disc region 186 between the hub region 184 and the peripheral rim region 188 may be integrally provided and are preferably equally angularly spaced relative to the central axis 54.
• the baffle member 170 in addition to tending to separate the high pressure chamber 180 from the remainder of the outer housing 12 also serves to transfer pressure loads generated by high pressure chamber 180 away from the inner region of the fixed scroll compressor body 110 and toward the outer peripheral region of the fixed scroll compressor body 110.
• the baffle member 170 is floatable relative to the fixed scroll compressor body 110 along the inner peripheral region. This can be accomplished, for example, as shown in the illustrated embodiment by a sliding cylindrical interface 192 between mutually cylindrical sliding surfaces of the fixed scroll compressor body and the baffle member along the respective hub regions thereof. As compressed high pressure refrigerant in the high pressure chamber 180 acts upon the baffle member 170, substantially no load may be transferred along the inner region, other than as may be due to frictional engagement.
• an axial contact interface ring 194 is provided at the radial outer periphery where the respective rim regions are located for the fixed scroll compressor body 110 and the baffle member 170.
• an annular axial gap 196 is provided between the innermost diameter of the baffle member 170 and the upper side of the fixed scroll compressor body 110.
• the annular axial gap 196 is defined between the radially innermost portion of the baffle member and the scroll member and is adapted to decrease in size in response to a pressure load caused by high pressure refrigerant compressed within the high pressure chamber 180. The gap 196 is allowed to expand to its relaxed size upon relief of the pressure and load.
• inner and outer seals 204, 206 may be provided, both of which may be resilient, elastomeric O-ring seal members.
• the inner seal 204 is preferably a radial seal and disposed in a radially inwardly facing inner groove 208 defined along the inner diameter of the baffle member 170.
• the outer seal 206 can be disposed in a radially outwardly facing outer groove 210 defined along the outer diameter of the baffle member 170 in the peripheral rim region 188. While a radial seal is shown at the outer region, alternatively or in addition an axial seal may be provided along the axial contact interface ring 194.
• the baffle member 170 could be a stamped steel component, preferably and as illustrated, the baffle member 170 comprises a cast and/or machined member (and may be aluminum) to provide for the expanded ability to have several structural features as discussed above. By virtue of making the baffle member in this manner, heavy stamping of such baffles can be avoided.
• the baffle member 170 can be retained to the fixed scroll compressor body 110. Specifically, as can be seen in the figures, a radially inward projecting annular flange 214 of the inner hub region 184 of the baffle member 170 is trapped axially between the stop plate 212 and the fixed scroll compressor body 110.
• the stop plate 212 is mounted with bolts 216 to a fixed scroll compressor body 210.
• the stop plate 212 includes an outer ledge 218 that projects radially over the inner hub 172 of the fixed scroll compressor body 110.
• the stop plate ledge 218 serves as a stop and retainer for the baffle member 170. In this manner, the stop plate 212 serves to retain the baffle member 170 to the fixed scroll compressor body 110 such that the baffle member 170 is carried thereby.
• Openings 232 are provided in the stop plate 212 to facilitate passage of compressed gas from the scroll compressor into the high pressure chamber 180.
• the check valve is operable to allow for one way directional flow such that when the scroll compressor is operating, compressed refrigerant is allowed to leave the scroll compressor bodies through the compression outlet 126 by virtue of the valve plate element 222 being driven off of its valve seat 230. However, once the drive unit shuts down and the scroll compressor is no longer operating, high pressure contained within the high pressure chamber 180 forces the movable valve plate element 222 back upon the valve seat 230. This closes off check valve 220 and thereby prevents backflow of compressed refrigerant back through the scroll compressor.
• the scroll compressor assembly 10 is operable to receive low pressure refrigerant at the housing inlet port 18 and compress the refrigerant for delivery to the high pressure chamber 180 where it can be output through the housing outlet port 20.
• an internal conduit 234 can be connected internally of the housing 12 to guide the lower pressure refrigerant from the inlet port 18 into the motor housing via a motor housing inlet 238. This allows the low pressure refrigerant to flow across the motor and thereby cool and carry heat away from the motor which can be caused by operation of the motor. Low pressure refrigerant can then pass longitudinally through the motor housing and around through void spaces therein toward the top end where it can exit through a plurality of motor housing outlets 240 (see FIG.
• the motor housing outlets 240 may be defined either in the motor housing 48, the upper bearing member 42 or by a combination of the motor housing and upper bearing member (e.g. by gaps formed therebetween as shown in FIG. 2).
• the low pressure refrigerant Upon exiting the motor housing outlet 240, the low pressure refrigerant enters an annular chamber 242 formed between the motor housing and the outer housing. From there, the low pressure refrigerant can pass through the upper bearing member through a pair of opposed outer peripheral through ports 244 that are defined by recesses on opposed sides of the upper bearing member 42 to create gaps between the bearing member 42 and housing 12 as shown in FIG. 3 (or alternatively holes in bearing member 42).
• the through ports 244 may be angularly spaced relative to the motor housing outlets 240.
• the low pressure refrigerant Upon passing through the upper bearing member 42, the low pressure refrigerant finally enters the intake area 124 of the scroll compressor bodies 110, 112. From the intake area 124, the lower pressure refrigerant finally enters the scroll ribs 114, 118 on opposite sides (one intake on each side of the fixed scroll compressor body) and is progressively compressed through chambers 122 to where it reaches it maximum compressed state at the compression outlet 126 where it subsequently passes through the check valve 220 and into the high pressure chamber 180. From there, high pressure compressed refrigerant may then pass from the scroll compressor assembly 10 through the refrigerant housing outlet port 20.
• the illustrated embodiment includes improvements in relation to the key coupling, which will additionally be focused upon below.
• each of the sliding contacts 250 is contained in its own separate quadrant 252 (the quadrants 252 being defined by the mutually perpendicular lateral axes 146, 154).
• Each sliding contact 250 can be provided by a sliding face 254 (e.g. such as an edge) defined by the movable scroll compressor body and another sliding face 256 defined by one of the keys 152 of the key coupling 140.
• cooperating pairs 258 of sliding contacts 250 are provided on each side of the first lateral axis 146.
• keys 152 are provided by the key coupling 140 and project from the ring body 142 to provide for the sliding faces 256, with the keys 152 projecting axially from the ring body 142 toward the movable scroll compressor body 112.
• the reverse may be true in that all or some of the keys may project from the base 120 of the movable scroll compressor body 112 instead.
• guide portions 156 of the movable scroll compressor body base 120 are provided by laterally extending flange portion 262 projecting in opposite directions along the second lateral axis 154 in an outward direction away from the movable compressor body scroll rib 118.
• the flange portions 262 can provide edges for the sliding faces 254 which lie in a plane parallel with a plane defined by the central axis 54 and the second lateral axis 154. Additionally, it can be seen that the flange portions 262 intersect and lie generally symmetrical upon the second lateral axis 154.
• the base 120 of the movable scroll compressor body 112 is slot free and need not define a slot due to the key coupling afforded with this design as compared with, for example, a more conventional design as illustrated in FIG. 10.
• One benefit of this approach is that space need not be occupied by outwardly projecting ears from the scroll base in order to interact with the Oldham key coupling.
• the housing can have a diameter of less than 320 millimeters. The reduction in size that can be realized by eliminating the ear structures is shown in FIG.
• the center shell can be reduced in diameter to under 310 millimeters to as little as 305 millimeters while providing up to thirty- five tons of capacity or even potentially more with a suitable motor (e.g. a forty ton capacity may be possible).
• a suitable motor e.g. a forty ton capacity may be possible.
• This can all be done while also realizing a significant weight savings, including roughly between 5-10 kilograms in weight savings of the shell alone due to the decreased diameter.
• This can provide significant benefits in relation to lightening the overall weight of the scroll compressor assembly 10 and thereby make it more attractive for several reasons including easier manipulation, easier installation, and material savings.
• comparable thirty-two ton scroll compressor displacement capacities have had shell sizes of greater than 330 millimeters such as 331 or 333 millimeters for example.
• a non-symmetrical contact relationship is also provided between the key coupler and at least one of the scroll compressor bodies as illustrated in FIG. 7.
• symmetric contact placement can cause unwanted rotation and edge loading of key surfaces indicated in FIG. 9.
• FIG. 7 show exaggerated placement of running clearances 270 considering running clearances are typically on the order of between ten micron and one hundred micron from a manufacturing design standpoint (not counting tolerances).
• running clearances 270 are provided to allow for easy sliding movement of the movable scroll compressor body 112 along the second lateral axis 154 and to allow for easier assembly.
• the running clearance 270 is not equal for each pair 258 of sliding contacts 250.
• sliding contacts 250a which continuously engage during operation, are set at about or around a zero running clearance while all or most of the running clearance is provided by sliding contacts 250b. Sliding contacts 250b can engage, for example, when the scroll compressor is shut down and to prevent relative rotation in the opposite direction and thereby keep the scroll compressor restrained for linear translation along the second lateral axis 154.
• each individual pair 258 of the keys 152 are non-symmetrically placed such that one key of the pair is placed slightly farther from the second lateral axis 154 as compared to the other key of that pair.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Rotary Pumps (AREA)
• Applications Or Details Of Rotary Compressors (AREA)

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• 2008
  • 2008-01-17 US US12/015,571 patent/US20090185927A1/en not_active Abandoned
• 2009
  • 2009-01-15 EP EP09701754.5A patent/EP2250345B1/en active Active
  • 2009-01-15 CN CN200980102291.2A patent/CN101952551B/zh active Active
  • 2009-01-15 JP JP2010543220A patent/JP2011510209A/ja active Pending
  • 2009-01-15 KR KR1020107017951A patent/KR101342409B1/ko not_active IP Right Cessation
  • 2009-01-15 WO PCT/US2009/031050 patent/WO2009091858A1/en active Application Filing

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