Scroll Pump

Abstract

The non-contact scroll pump (100) includes an orbiting scroll (130), a fixed scroll (120), and a drive shaft (140) coupled to the orbiting scroll, the drive shaft being axially movable relative to the fixed scroll. The non-contact scroll pump further includes an annular bearing (160b) extending around the drive shaft to support and facilitate rotation of the drive shaft, and a diaphragm (180) mounted to the annular bearing for supporting the annular bearing, the diaphragm being axially flexible to allow the annular bearing to move axially, thereby facilitating axial mobility of the drive shaft relative to the fixed scroll.

Description

[Technical field]

[0001] The present invention relates to a scroll pump. [Background technology]

[0002] Scroll pumps are a known type of pump used in a variety of different industries to pump fluids. Scroll pumps work by utilizing the relative motion of two intermeshing scrolls, known as a fixed scroll and an orbiting scroll, to pump a fluid. Each of the fixed scroll and the orbiting scroll includes a spiral wall extending from a base.

[0003] One type of scroll pump is a non-contact scroll pump. In a non-contact scroll pump, the tips (i.e., the ends of the spiral walls) of the fixed scroll and the orbiting scroll do not come into contact with the other scroll. Furthermore, in a non-contact scroll pump, there are no tip seals between the tips of the fixed scroll and the orbiting scroll and the other scroll. Thus, in a non-contact scroll pump, there is a small gap (or clearance), for example 10-20 microns, between the tips of the fixed scroll and the orbiting scroll and the other scroll. Summary of the Invention [Means for solving the problem]

[0004] In one aspect of the invention, a non-contact scroll pump is provided that includes an orbiting scroll, a fixed scroll, and a drive shaft coupled to the orbiting scroll, the drive shaft being axially movable relative to the fixed scroll. The non-contact scroll pump further includes an annular bearing extending around the drive shaft to support and facilitate rotation of the drive shaft, and a diaphragm mounted on the annular bearing to support the annular bearing, the diaphragm being axially flexible to allow the annular bearing to move axially, thereby facilitating axial movement of the drive shaft relative to the fixed scroll.

[0005] The diaphragm is radially stiff and capable of resisting radial movement of the annular bearing.

[0006] The diaphragm may mechanically couple the annular bearing to the fixed scroll.

[0007] The diaphragm may mechanically couple the annular bearing to a housing portion of the non-contact scroll pump.

[0008] The non-contact scroll pump includes a first annular bearing and a second annular bearing, both of which extend around the drive shaft to support and assist in rotation of the drive shaft.

[0009] The diaphragm can mechanically couple the first annular bearing to the fixed scroll and the second annular bearing can be mechanically coupled to a housing portion of the non-contact scroll pump, the second annular bearing being capable of sliding axially relative to the housing portion, thereby facilitating axial movement of the drive shaft relative to the fixed scroll.

[0010] The diaphragm can mechanically couple the first annular bearing to the fixed scroll, and the second annular bearing can be mechanically coupled to a housing portion of the non-contact scroll pump by an additional diaphragm attached to the second annular bearing to support the second annular bearing, the additional diaphragm being axially flexible to allow the second annular bearing to move axially, thereby facilitating axial movement of the drive shaft relative to the fixed scroll.

[0011] The additional diaphragm is radially stiff and is capable of impeding radial movement of the second annular bearing.

[0012] The diaphragm may be made of steel or aluminum.

[0013] The non-contact scroll pump may further include a preload spring arranged to provide a preload force on the drive shaft acting to bias the orbiting scroll away from the fixed scroll.

[0014] In another aspect of the present invention, a non-contact scroll pump is provided that includes a fixed scroll, an orbiting scroll in mesh with the fixed scroll, an annular bearing coupled to the orbiting scroll, a crank sleeve coupled to the annular bearing, and a drive shaft coupled to the crank sleeve. The drive shaft is arranged to cause the orbiting scroll to orbit via the crank sleeve and the annular bearing. The crank sleeve is axially movable relative to the drive shaft, thereby permitting axial movement of the orbiting scroll relative to the fixed scroll.

[0015] The non-contact scroll pump may further include a biasing mechanism arranged to provide an axial biasing force to the crank sleeve acting through the crank sleeve and the annular bearing to urge the orbiting scroll away from the fixed scroll.

[0016] The biasing mechanism may be a preload spring.

[0017] In another aspect of the present invention, a vacuum pump system is provided that includes a plurality of vacuum pumps, one of which is the non-contact scroll pump of the above aspect.

[0018] In yet another aspect of the present invention, there is provided a use of the non-contact scroll pump of any of the above aspects for pumping a fluid. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram (not to scale) showing a cross section of a non-contact scroll pump. [Diagram 2] FIG. 2 is a schematic diagram (not to scale) showing an enlarged cross-sectional view of a thrust bearing assembly of a non-contact scroll pump. [Diagram 3]FIG. 1 is a schematic diagram (not to scale) showing a perspective view of multiple thrust bearing assemblies of a non-contact scroll pump. [Figure 4] FIG. 1 is a schematic diagram (not to scale) showing an enlarged perspective view of a portion of a thrust bearing assembly of a non-contact scroll pump. [Diagram 5] FIG. 1 is a schematic diagram (not to scale) showing an enlarged perspective view of a portion of a main bearing assembly of a non-contact scroll pump. [Figure 6] FIG. 2 is a schematic diagram (not to scale) showing an enlarged cross-sectional view of a portion of a non-contact scroll pump according to an alternative construction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] FIG. 1 is a schematic diagram (not to scale) showing a cross-section of a non-contact scroll pump 100.

[0021] Scroll pump 100 includes a housing portion 110 , a fixed scroll 120 , an orbiting scroll 130 , a drive shaft 140 , an actuator 150 , a main bearing assembly 160 , and a number of thrust bearing assemblies 170 .

[0022] In this embodiment, the housing portion 110 and the fixed scroll 120 together define an overall housing for the scroll pump 100 within which the other components of the scroll pump 100 are disposed. However, it should be understood that in other embodiments, the fixed scroll 120 does not define a portion of the overall housing for the scroll pump 100, but instead can be entirely disposed within the overall housing. In this embodiment, the orbiting scroll 130 is disposed within the overall housing for the scroll pump 100.

[0023] The orbiting scroll 130 is intermeshed with the fixed scroll 120 to define a space (or flow path) through which the scroll pump 100 pumps a fluid (e.g., gas) during operation. The orbiting scroll 130 is configured to orbit relative to the fixed scroll 120 to pump a fluid from an inlet (not shown) of the scroll pump 100 to an outlet (not shown) of the scroll pump 100. The exact physical mechanisms by which fluid is pumped by the orbiting scroll 130 relative to the fixed scroll 120 are well understood and will not be described herein for the sake of brevity.

[0024] The fixed scroll 120 includes a first base 122 and a first spiral wall 124. The orbiting scroll 130 includes a second base 132 and a second spiral wall 134. The first spiral wall 124 and the second spiral wall 134 are interdigitated with each other. Furthermore, the first spiral wall 124 extends vertically from the first base 122 to the second base 132, and an end face (also called a tip) of the first spiral wall 124 is close to but does not contact (e.g., 10-20 microns away) the opposing surface of the second base 132. The second spiral wall 134 extends vertically from the second base 132 to the first base 122, and an end face (or tip) of the second spiral wall 134 is close to but does not contact (e.g., 10-20 microns away) the opposing surface of the first base 122. Thus, a gap or clearance exists (e.g., 10-20 microns) between the end faces of the first and second spiral walls 124, 134 and the opposing faces of the first and second bases 122, 132, respectively. The distance between the end face of the first spiral wall 124 and the opposing face of the second base 132 is the same as the distance between the second spiral wall 134 and the opposing face of the first base 122. The gap is empty in the sense that no object or other scroll pump component is disposed within the gap. For example, no tip seal is present within the gap. Thus, the end faces of the first and second spiral walls 124, 134 are not in contact with any object or other scroll pump component.

[0025] In this embodiment, the first base 122 and the first helical wall 124 are integrally formed with one another, and the second base 132 and the second helical wall 134 are integrally formed with one another. However, in other embodiments, one or both of the helical walls 124, 134 are not integrally formed with their respective bases 122, 132.

[0026] A drive shaft 140 is coupled to the orbiting scroll 130 and is configured to rotate to cause the orbiting scroll 130 to orbit. The drive shaft 140 is disposed within the overall housing of the scroll pump 100 and is mounted via a main bearing assembly 160 which aids in the rotation of the drive shaft 140. In this embodiment, the drive shaft 140 extends through both the fixed scroll 120 and the orbiting scroll 130, with the orbiting scroll 130 attached to the end of the drive shaft 140.

[0027] An actuator 150 (e.g., an electric motor) is coupled to the drive shaft 140 and configured to actuate the drive shaft 140 to rotate the drive shaft 140 and cause the orbiting scroll 130 to orbit. The actuator 150 is disposed within the overall housing of the scroll pump 100 and is mounted about the drive shaft 140.

[0028] A main bearing assembly 160 mechanically couples the drive shaft 140 to the orbiting scroll 130 and the overall housing of the scroll pump 100 such that the drive shaft 140 can rotate within the scroll pump 100 and drive the orbiting scroll 130 .

[0029] Each of the plurality of thrust bearing assemblies 170 is disposed between the orbiting scroll 130 and the housing portion 110 that is axially spaced from the orbiting scroll 130. Each thrust bearing assembly 170 is coupled (and engaged) to the orbiting scroll 130 to constrain and / or control the axial position of the orbiting scroll 130 relative to the fixed scroll 120. In this embodiment, the three thrust bearing assemblies 170 are evenly angularly distributed in a triangular configuration about the central axis of rotation of the orbiting scroll 130 (this is further shown in FIG. 3) to provide a steady axial force to the orbiting scroll 130. The exact configuration of each thrust bearing assembly is described in more detail below with reference to FIG. 2.

[0030] FIG. 2 is a schematic diagram (not to scale) showing an enlarged cross-sectional view of thrust bearing assembly 170 of non-contact scroll pump 100.

[0031] Thrust bearing assembly 170 includes a first plate 171, a second plate 172, a first ball bearing cage 173a, a second ball bearing cage 173b, a plurality of ball bearings 174, an adjustment pin 175, and a casing 176. Through these structures, thrust bearing assembly 170 provides axial support for orbiting scroll 130 while also assisting orbiting scroll 130 during operation, as described in more detail below.

[0032] Each of the first and second plates 171, 172 has a first side facing the orbiting scroll 130 and a second side opposite the first side facing away from the orbiting scroll 130. Each of the first and second ball bearing cages 173a, 173b has a first side facing the orbiting scroll 130 and a second side opposite the first side facing away from the orbiting scroll 130. The first side of the first plate 171 is fixed to the back surface of the orbiting scroll 130, and the second side of the first plate 171 is fixed to the first side of the first ball bearing cage 173a. The second side of the first ball bearing cage 173a is spaced from the first side of the second ball bearing cage 173b by a ball bearing 174, thereby allowing relative movement between the first and second ball bearing cages 173a, 173b. A second side of the second ball bearing cage 173b is fixed to a first side of the second plate 172. A second side of the second plate 172 engages an end of an adjustment pin 175.

[0033] Each of the first and second ball bearing cages 173a, 173b includes a plurality of holes within which a plurality of ball bearings 174 are disposed. Each hole in the first ball bearing cage 173a overlaps with a corresponding hole in the second ball bearing cage 173b to form a plurality of hole pairs. Each hole pair accommodates a single ball bearing 174. The hole overlap allows the first and second bearing cages 173a, 173b to accommodate the orbiting motion of the orbiting scroll 130 during operation while constraining the movement of the ball bearings 174. This is further shown in FIG.

[0034] The plurality of ball bearings 174 are sandwiched between the first and second plates 171, 172 such that each of the first and second plates 171, 172 contacts a ball bearing 174. Each of the plurality of ball bearings 174 is received within a respective pair of holes in the first and second ball bearing cages 173a, 173b. The plurality of ball bearings 174 may be formed from steel or ceramic.

[0035] During operation, the plurality of ball bearings 174 roll against the first and second plates 171, 172 in pairs of holes in the first and second ball bearing cages 173a, 173b to assist in the orbiting scroll 130 orbiting. During operation of the scroll pump 100, the first plate 171 and the first ball bearing cage 173a, which are fixed to each other and to the orbiting scroll 130, move together with the orbiting scroll 130. Thus, during operation, the first plate 171, the first ball bearing cage 173a, and the orbiting scroll 130 all move together against the second plate 172 and the second ball bearing cage 173b on the plurality of ball bearings 174.

[0036] The adjustment pin 175 extends axially between the housing portion 110 and the second plate 172 of the scroll pump 100. A first end 175a of the adjustment pin 175 is attached to the housing portion 110, and a second end 175b opposite the first end 175a of the adjustment pin 175 engages a second side of the second plate 172. The first end 175a of the adjustment pin 175 is threadedly coupled to the housing portion 110 with a corresponding threaded nut 175c. The threaded nut 175c is on the first end 175a of the adjustment pin 175 and is rotatable on the threads of the first end 175a to adjust the axial position of the adjustment pin 175, thereby facilitating control of the axial position of the orbiting scroll 130 with the remainder of the thrust bearing assembly 170.

[0037] The second end 175b of the adjustment pin 175 seats in a tapered recess 172a in the second side of the second plate 172. The tapered recess 172a has a generally conical shape. More specifically, the second end 175b of the adjustment pin 175 includes a rounded surface that engages with a surface of the second side of the second plate 172 that defines the tapered recess 172a. In this manner, the rounded surface of the second end 175b of the adjustment pin 175 and the surface that defines the tapered recess 172a together form a ball and socket joint, which allows the second plate 172 and the second ball bearing cage 173b to articulate / rotate on the first end 175b of the adjustment pin 175.

[0038] The casing 176 surrounds the adjustment pin 175 and acts as a barrier to prevent escape of the lubricant (e.g., oil or grease) used in the ball bearing 174, the first and second bearing cages 173a, 173b, and the first and second plates 171, 172. In this embodiment, the casing 176 has a bellows shape.

[0039] 3 is a schematic diagram (not to scale) illustrating a perspective view of multiple thrust bearing assemblies 170 of a non-contact scroll pump 100. As shown, in this embodiment, the scroll pump 100 includes three thrust bearing assemblies 170 that are evenly angularly distributed in a triangular configuration about the central axis of rotation of the orbiting scroll 130 to provide a steady axial force to the orbiting scroll.

[0040] FIG. 4 is a schematic diagram (not to scale) illustrating an enlarged perspective view of a portion of the thrust bearing assembly 170 of the non-contact scroll pump 100. Specifically, FIG. 4 illustrates an enlarged view of the first and second bearing cages 173a, 173b of the thrust bearing assembly 170. As shown, each hole in the first ball bearing cage 173a overlaps with a corresponding hole in the second ball bearing cage 173b to form a plurality of hole pairs. Each of the ball bearings 174 is disposed within a respective hole pair (only one ball bearing 174 is depicted in FIG. 4).

[0041] FIG. 5 is a schematic diagram (not to scale) illustrating an enlarged cross-sectional view of a portion of main bearing assembly 160 of non-contact scroll pump 100.

[0042] To permit axial movement of the orbiting scroll 130, a mechanism is required which cooperates with a main bearing assembly 160 which supports a drive shaft 140 which drives the orbiting scroll 130. This is described below with reference to FIG.

[0043] In this embodiment, the main bearing assembly 160 includes a first bearing 160a, a second bearing 160b, and a third bearing 160c. The first bearing 160a, the second bearing 160b, and the third bearing 160c are annular bearings that extend around the drive shaft 140. The first bearing 160a is disposed (mechanically coupled) between the orbiting scroll 130 and the first end of the drive shaft 140. The second bearing 160b is disposed (mechanically coupled) between the fixed scroll 120 and the drive shaft 140. The second bearing 160b is supported by the fixed scroll 120 via a diaphragm 180. The third bearing 160c is disposed (mechanically coupled) between the second end of the drive shaft 140 and the entire housing of the scroll pump 100. The second bearing 160b is disposed between the first bearing 160a and the third bearing 160c in the axial direction.

[0044] The scroll pump 100 includes a diaphragm 180 disposed between the second bearing 160b and the fixed scroll 120. The diaphragm 180 is attached to the second bearing 160b, surrounds the second bearing 160b, and mechanically couples the second bearing 160b to the fixed scroll 120. The diaphragm 180 is attached to the fixed scroll 120 at the radial outer periphery of the diaphragm 180. The diaphragm 180 extends circumferentially around the second bearing 160b and supports the second bearing 160b in its proper position. In other words, the diaphragm 180 includes a hole, and the second bearing 160b is disposed in the hole while being attached to the diaphragm 180 via the edge of the diaphragm 180 that defines the hole. The diaphragm 180 supports the second bearing 160b while being axially flexible to allow the second bearing 160b to move axially relative to the fixed scroll 120. The diaphragm 180 also has high radial stiffness to impede and / or prevent the second bearing 160b from moving radially. The diaphragm 180 may be formed from, for example, steel or aluminum.

[0045] In this embodiment, the third bearing 160c is mounted in the housing portion 200 within a bore of the housing portion 200 such that the third bearing 160c is axially slidable relative to the housing portion 200. This allows the third bearing 160c to move axially within the bore relative to the housing portion 200 and the fixed scroll 120. An O-ring is disposed within the bore around the third bearing 160c between the third bearing 160c and the housing portion 200 to center the third bearing 160c within the bore and reduce noise due to movement of the third bearing 160c. Both the second bearing 160b and the third bearing 160c are movable, allowing the drive shaft 140 to move axially, which in turn allows the orbiting scroll 130 to move axially.

[0046] In this embodiment, the scroll pump 100 further includes a preload spring 190 that applies a preload force to the third bearing 160c. In this embodiment, the preload spring 190 is disposed axially between the third bearing 160c and the rear portion 210 of the housing. This preload force acts through the third bearing 160c and the drive shaft 140 to preload the orbiting scroll 130 in the axial direction away from the fixed scroll 120 and toward the thrust bearing assembly described above. This preload force, combined with the axial mobility of the drive shaft 140 and the thrust bearing assembly, allows the desired axial clearance between the orbiting scroll 130 and the fixed scroll 120 to be consistently and accurately maintained.

[0047] Advantageously, the use of the diaphragm 180 described above helps to avoid fretting problems that occur with other mechanisms for allowing bearings to move axially, such as the sliding mechanism described with respect to the third bearing 160c.

[0048] Advantageously, the use of diaphragm 180 as described above helps to enable the radial position of orbiting scroll 130 to be maintained very accurately due to the high radial stiffness of diaphragm 180. Diaphragm 180 eliminates radial movement of drive shaft 140 in the plane of second bearing 160b, thereby reducing radial clearance variations between the scrolls and allowing smaller radial clearances to be used.

[0049] Advantageously, the flexibility of diaphragm 180 allows second bearing 160b to tilt into perfect alignment with drive shaft 140. Thus, third bearing 160c and housing portion 200 can be repositioned by radially moving them without stressing second bearing 160b.

[0050] In a further embodiment (not shown), the third bearing 160c is supported by a diaphragm similar to the second bearing 160b, instead of being supported using the slide mechanism described above. In other words, in this embodiment, the scroll pump 100 includes an additional diaphragm disposed between the third bearing 160c and the housing part 200. The additional diaphragm is attached to the third bearing 160c, surrounds the third bearing 160c, and mechanically couples the third bearing 160c to the housing part 200. The additional diaphragm supports the third bearing 160c while being axially flexible to allow the third bearing 160c to move axially relative to the housing part 200. The additional diaphragm also has high radial stiffness to impede and / or prevent the third bearing 160c from moving radially.

[0051] FIG. 6 is a schematic diagram (not to scale) illustrating an enlarged cross-sectional view of a portion of a non-contact scroll pump 100 in accordance with another embodiment.

[0052] The embodiment of Figure 6 is the same as the embodiment of Figure 5 (like reference numerals refer to like elements), except that instead of having a diaphragm 180, scroll pump 100 includes an axially movable crank sleeve 185 and a biasing mechanism 186 for controlling the axial position of orbiting scroll 130. In the embodiment of Figure 6, second bearing 160b is fixed and first bearing 160a is movable.

[0053] The crank sleeve 185 is an element present in the scroll pump that provides a crank offset to impart an orbiting path to the orbiting scroll 130 of the scroll pump 100. The crank sleeve 185 extends around the drive shaft 140 and is coupled to the orbiting scroll 130 via the first bearing 160a. The crank sleeve 185 is an eccentric member having a center of rotation that is parallel to, but radially offset from, the axis of rotation of the drive shaft 140 to provide a crank offset for the orbiting of the orbiting scroll 130.

[0054] In this embodiment, the crank sleeve 185 is axially movable (or slidable) relative to the drive shaft 140 to permit axial movement of the orbiting scroll 130 relative to the fixed scroll 120. Specifically, the crank sleeve 185 is attached to the first bearing 160a, which is attached to the orbiting scroll 130. Thus, axial movement of the crank sleeve 185 causes axial movement of the orbiting scroll 130 due to the attachment of the orbiting scroll 130 to the first bearing 160a and the attachment of the first bearing 160a to the crank sleeve 185.

[0055] The biasing mechanism 186 is arranged to provide an axial biasing force to the crank sleeve 185, which acts through the crank sleeve 185 and the first bearing 160a to bias the orbiting scroll 130 away from the fixed scroll 120. In this embodiment, the biasing mechanism 186 is a preload spring that extends axially between a shoulder of the drive shaft 140 and the crank sleeve 185. Because the crank sleeve 185 is axially movable relative to the drive shaft 140, the particular biasing force provided by the biasing mechanism 186 can be selected to maintain stability of the orbiting scroll 130 by maintaining a required axial load through each of the multiple thrust bearing assemblies 170. Thus, a desired axial clearance between the orbiting scroll 130 and the fixed scroll 120 can be maintained.

[0056] The non-contact scroll pump 100 described above can be used as part of a vacuum pumping system that may include multiple pumps and / or other components.

[0057] It will be appreciated that various modifications / variations can be made to the above-described embodiments without departing from the scope of the present invention.

[0058] In the embodiment described above, the scroll pump includes three separate thrust bearing assemblies, however, in other embodiments, the scroll pump includes a different number of thrust bearing assemblies, for example, only one, only two, or four or more thrust bearing assemblies.

[0059] In the above described embodiment, the thrust bearing assembly comprises multiple ball bearings, however, in other embodiments, the thrust bearing assembly comprises only one ball bearing.

[0060] In the embodiment described above, the thrust bearing assembly includes a ball bearing cage that constrains the movement of the ball bearings, however, in other embodiments the ball bearing cage is omitted.

[0061] In the embodiment described above, elongated alignment pins are used to couple the housing to the second plate, however, in other embodiments, different types of coupling structures, for example, different types of elongated members, can be used. [Explanation of symbols]

[0062] 100 Non-contact scroll pump 110 Housing 120 Fixed Scroll 122 Base of fixed scroll 124: Fixed scroll spiral wall 130 Swivel Scroll 132 Rotating scroll base 134 Spiral Wall of the Rotating Scroll 140 Drive shaft 150 Actuator 160 Main bearing assembly 160a first bearing 160b Second bearing 160c 3rd bearing 170 Thrust bearing assembly 171 First Plate 172 Second Plate 172a Recess 173a first ball bearing cage 173b Second ball bearing cage 174 Ball Bearings 175 Adjustment pin 175a first end of adjustment pin 175b second end of adjustment pin 175c nut 176 Casing 180 Diaphragm 185 Crank Sleeve 186 Biasing mechanism 190 Preload spring 200 Housing part 210 Rear of housing

Claims

1. Rotating scroll, Fixed scrolling and a drive shaft coupled to the orbiting scroll and axially movable relative to the fixed scroll; an annular bearing extending around the drive shaft for supporting the drive shaft and assisting in rotation of the drive shaft; a diaphragm attached to the annular bearing for supporting the annular bearing; A non-contact scroll pump comprising: A non-contact scroll pump, wherein the diaphragm is axially flexible to allow axial movement of the annular bearing, thereby facilitating axial movement of the drive shaft relative to the fixed scroll.

2. 2. The non-contact scroll pump of claim 1, wherein said diaphragm is radially stiff to resist radial movement of said annular bearing.

3. 3. The non-contact scroll pump of claim 1, wherein the diaphragm mechanically couples the annular bearing to the fixed scroll.

4. 4. The non-contact scroll pump of claim 1, wherein the diaphragm mechanically couples the annular bearing to a housing portion of the non-contact scroll pump.

5. 5. The non-contact scroll pump of claim 1, further comprising a first annular bearing and a second annular bearing, both of which extend around the drive shaft to support the drive shaft and aid in the rotation of the drive shaft.

6. the diaphragm mechanically couples the first annular bearing to the fixed scroll; the second annular bearing is mechanically coupled to the housing portion of the non-contact scroll pump; 6. The non-contact scroll pump of claim 5, wherein the second annular bearing is axially slidable relative to the housing portion, thereby facilitating axial movement of the drive shaft relative to the fixed scroll.

7. the diaphragm mechanically couples the first annular bearing to the fixed scroll; the second annular bearing is mechanically coupled to the housing portion of the non-contact scroll pump by an additional diaphragm attached to the second annular bearing for supporting the second annular bearing; 6. The non-contact scroll pump of claim 5, wherein the additional diaphragm is axially flexible to allow the second annular bearing to move axially, thereby facilitating axial mobility of the drive shaft relative to the fixed scroll.

8. 8. The non-contact scroll pump of claim 7, wherein the additional diaphragm is radially stiff to impede radial movement of the second annular bearing.

9. 9. The non-contact scroll pump according to claim 1, wherein the diaphragm is made of steel or aluminum.

10. 10. The non-contact scroll pump of claim 1, further comprising a preload spring arranged to provide a preload force on the drive shaft acting to bias the orbiting scroll away from the fixed scroll.

11. Fixed scrolling and an orbiting scroll that meshes with the fixed scroll; an annular bearing coupled to the orbiting scroll; a crank sleeve coupled to the annular bearing; a drive shaft coupled to the crank sleeve and disposed to cause the orbiting scroll to orbit via the crank sleeve and the annular bearing; A non-contact scroll pump comprising: The crank sleeve is axially movable relative to the drive shaft, thereby permitting axial movement of the orbiting scroll relative to the fixed scroll.

12. 12. The non-contact scroll pump of claim 11, further comprising a biasing mechanism positioned to provide an axial biasing force to said crank sleeve acting through said crank sleeve and said annular bearing to urge said orbiting scroll away from said fixed scroll.

13. 13. The non-contact scroll pump of claim 12, wherein the biasing mechanism is a preload spring.

14. A vacuum pump system comprising a plurality of vacuum pumps, one of which is a non-contact scroll pump according to any one of claims 1 to 13.

15. Use of a non-contact scroll pump according to any one of claims 1 to 13 for pumping a fluid.

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