A vortex pump

Abstract

A scroll pump and a scroll vacuum pump are disclosed. The scroll vacuum pump comprises an orbiting scroll portion, a fixed scroll portion, and a pump housing surrounding a pump chamber of the scroll vacuum pump. The pump also includes an axially extending drive shaft having an eccentric shaft portion, the orbiting vortex portion being mounted on the eccentric shaft portion so that rotation of the drive shaft imparts an orbiting motion to the orbiting vortex portion relative to the fixed vortex portion; an axial adjustment mechanism for adjusting the axial position of the orbiting vortex portion and thereby adjusting the distance between the fixed vortex portion and the orbiting vortex portion, the axial adjustment mechanism including a plurality of adjustment members angularly spaced about the drive shaft and extending through the pump housing toward the orbiting vortex portion, the plurality of adjustment members each being configured to provide an independently adjustable axial position of the orbiting vortex portion; and a plurality of sealing devices for isolating the plurality of adjustment members from the pump chamber, the plurality of sealing devices extending around each of the plurality of adjustment members and including at least one flexible portion so that one end of the sealing device can orbit relative to another fixed end of the sealing device.

Description

Technical Field

[0001] The field of the present invention relates to scroll pumps, and a specific example relates to vacuum scroll pumps. Background Art

[0002] A scroll pump is formed of two staggered scrolls mounted so that rotation of the drive shaft imparts orbital motion to one of the scrolls relative to the other, thereby trapping and pumping or compressing pockets of fluid between the scrolls. In some cases, one of the scrolls is fixed and the other is mounted on a drive shaft with an eccentric cam so that it orbits eccentrically without rotating.

[0003] Conventional scroll pumps have been provided with tip seals mounted on the ends of the spiral scroll walls and configured to contact the opposing scroll plates to provide a seal between the scrolls, thereby allowing the fluid pockets to be effectively pushed from the inlet to the outlet. Although tip seals provide an effective seal, they degrade over time, requiring replacement and generating dust that can contaminate a clean environment.

[0004] WO 2017 / 220961 describes a vacuum scroll pump in which the problem of the end seal is solved by using an axial thrust bearing having an axial adjustment mechanism that allows the axial clearance to be adjusted and reduced to a low level. In this way, a sufficiently small axial clearance is provided to provide effective pumping without the need for an end seal.

[0005] While such axial thrust bearings solve many of the problems created by tip seals, they present their own challenges as the bearings require lubricant and this can leak into the pumping area and itself cause contamination.

[0006] It would be desirable to provide a scroll pump having effective sealing and pumping capabilities as well as low contamination. Summary of the invention

[0007] A first aspect provides a vortex vacuum pump, comprising: an orbiting vortex portion; and a fixed vortex portion; a pump housing, the pump housing surrounding a pump chamber of the vortex vacuum pump; an axially extending drive shaft, the drive shaft having an eccentric shaft portion, the orbiting vortex portion being mounted on the eccentric shaft portion so that rotation of the drive shaft imparts an orbiting motion relative to the fixed vortex portion to the orbiting vortex portion; an axial adjustment mechanism for adjusting the axial position of the orbiting vortex portion, and thereby adjusting the distance between the fixed vortex portion and the orbiting vortex portion, the axial adjustment mechanism comprising a plurality of adjustment members, the plurality of adjustment members being angularly spaced around the drive shaft and extending through the pump housing toward the orbiting vortex portion, the plurality of adjustment members each being configured to provide an independently adjustable axial position of the orbiting vortex portion; and a plurality of sealing devices for isolating the plurality of adjustment members from the pump chamber, the plurality of sealing devices extending around each of the plurality of adjustment members and comprising at least one flexible portion so that one end of the sealing device can orbit relative to the other fixed end of the sealing device.

[0008] The inventors of the present invention have recognized that a plurality of adjustment members extending through the pump housing and controlling the axial position of the orbiting vortex at a plurality of different points not only allow for adjustment of the gap between the vortexes, but also solve the tilt and swash problems associated with the orbiting vortex, at least to some extent. However, such members extend into the pump housing at interfaces that allow axial movement of the members. In addition, axial positioning of the orbiting vortex by these components requires some contact between one or more orbiting surfaces and non-orbiting surfaces. These two problems can lead to leakage into the pump chamber within the pump housing and / or contamination of the pump chamber within the pump housing. The inventors of the present invention have recognized that these two problems can be solved by isolating each adjustment member from the pump chamber with a plurality of sealing devices, which extend around each of the plurality of adjustment members. These sealing devices are formed by at least one flexible portion that allows one end of the sealing device to orbit relative to a fixed portion at the other end. In this way, an effective seal can be provided between the orbiting surface and the fixed surface. Furthermore, by providing a plurality of sealing means around each individual regulating member, rather than providing one sealing means around them all, the width of such sealing means is allowed to be reduced, thereby reducing the amount of material required and providing a more compact sealing means. Such a reduction in width may allow the length of the sealing means to be correspondingly reduced, which in turn allows the length of the pump to be reduced. This results not only in a more compact pump, but also in a pump that is less susceptible to the differential thermal expansion of different components. Lower thermal expansion differences help to maintain precise control of the position of the orbiting scroll portion, thereby allowing the end seal to be omitted while providing an effective sealing means.

[0009] In some embodiments, the plurality of sealing devices each comprises a bellows.

[0010] Although the sealing means may be formed in different ways, as long as at least a portion of the sealing means is flexible, a bellows is an effective sealing means that also serves to inhibit rotation of the orbiting scroll portion. For a bellows, the flexibility to allow orbiting motion increases with the length of the bellows and increases inversely with the width. Thus, providing a separate narrower bellows corresponding to each regulating member allows them to be shorter while still providing similar flexibility and similar fatigue life to wider, longer bellows. Thus, the bellows that surround the individual regulating members with their reduced diameter can have a correspondingly reduced length.

[0011] The bellows can be formed from a variety of materials including metals and polymers. The polymer can include a heat-resistant polymer such as PTFE (polytetrafluoroethylene).

[0012] In some embodiments, the plurality of seals are each attached at one end to the pump housing and at another end to at least one surface that orbits with the orbiting scroll.

[0013] The seal may be configured to seal between the pump housing and a surface that orbits with the orbiting scroll. In this way, the seal member is fixed to the surface so that there is no relative movement between the seal and the surface, all relative movement is within the flexible portion of the seal. This reduces wear at the connecting surfaces, increases seal life, and provides a hermetic seal without contamination of the sliding surfaces.

[0014] In some embodiments, the axial adjustment mechanism comprises an axial thrust bearing device, and the axial thrust bearing device comprises:

[0015] a plurality of ball bearings mounted between the orbiting scroll portion and at least one thrust surface; and

[0016] The plurality of adjustment members are each configured to independently adjust an axial position of the at least one thrust surface.

[0017] Although the axial adjustment mechanism may have a variety of forms, for example, it may include three miniature cranks for mounting the orbiting scroll, in some cases it includes an axial thrust bearing, the arrangement of which is particularly effective in providing precise axial positioning of different positions of the orbiting scroll controlled by the adjustment member. The axial thrust bearing has a ball bearing mounted between the thrust surface and the orbiting scroll, which is the interface for relative motion between the surfaces and is lubricated to reduce friction and wear. The sealing arrangement provides an effective way to isolate the lubricant from the pump chamber defined by the pump housing.

[0018] In some embodiments, the at least one thrust surface is mounted on ends of the plurality of adjustment members.

[0019] The axial adjustment mechanism may include an axial thrust bearing having a thrust surface located on the end of the axial adjustment member and abutting against a ball bearing, which in turn abuts against the orbiting scroll portion. In this regard, the ball bearing may abut against the thrust surface on the orbiting scroll portion. Adjustment of the axial position of the axial member adjusts the position of the thrust surface and thus adjusts the axial position of the orbiting scroll portion via the ball bearing.

[0020] In some embodiments, the at least one thrust surface is mounted on ends of the plurality of adjustment members.

[0021] In some cases, the axial thrust bearing may be a single axial thrust bearing having a single thrust surface mounted on each of the plurality of adjustment members.

[0022] In some embodiments, the at least one thrust surface comprises an annular surface facing the orbiting scroll and extending around a central axis of the orbiting scroll.

[0023] Where the thrust surface is a single thrust surface mounted on multiple adjustable members, then in some embodiments it may be an annular surface facing the orbiting scroll and extending around the central axis of the orbiting scroll. The ball bearings themselves are arranged in an annular arrangement and are pushed against the orbiting scroll by the annular thrust surface. The width of the annular surface is sufficient to allow the ball bearings to move in a circular motion as the orbiting scroll orbits while still remaining within the annular thrust surface.

[0024] In some embodiments, the at least one thrust surface is mounted such that a radial center point of the at least one thrust surface is between 30% and 80% of a radius of the orbiting scroll portion.

[0025] Although the thrust surface may be mounted in a number of different locations, in some cases it may be mounted between 30% and 80% of the radius of the orbiting scroll. In this regard, it may be advantageous to have it towards the outer edge, perhaps between 60% and 80% of the radius, where independent adjustment has an increased effect on the pitch and wobble of the orbiting scroll and thereby provides additional axial support, resulting in reduced warping of the orbiting scroll.

[0026] In some embodiments, the scroll vacuum pump also includes at least one receiving member mounted on the orbiting scroll portion, the at least one receiving member surrounds the ball bearing and includes the at least one surface, the multiple adjustment members each extend through a corresponding hole in the at least one surface, and the other ends of the multiple sealing members are sealed to the at least one surface around the multiple holes.

[0027] As previously mentioned, the seal may be attached between the surface that orbits with the scroll and the surface of the pump housing, and this attachment is such that there is no sliding surface that allows the seal to be airtight and flexibility that allows movement within the flexible portion of the seal. One way of doing this may be to provide a receiver that surrounds the ball bearing and thrust surface and has a hole through which the adjustment member extends.

[0028] In some embodiments, the receiver has an annular form and is constructed and mounted to surround the annular thrust surface, the at least one surface comprises a single annular surface and includes a plurality of holes at locations corresponding to the plurality of adjustment members.

[0029] In the case of a single thrust bearing of annular form, the receiver may also have annular form and be configured to surround the annular thrust surface. In this case, a plurality of holes are present in the surface of the annular receiver facing away from the orbiting scroll portion.

[0030] In some embodiments, the axial thrust bearing arrangement includes a retainer including an inner race and an outer race extending vertically around a central axis of the orbiting scroll portion and configured to retain the ball bearing between the races.

[0031] Where the axial thrust bearing is a single annular bearing, then there may be retaining means for retaining the ball bearing within the annular structure. The retaining means may be mounted on the orbiting scroll and orbit with the orbiting scroll.

[0032] In other embodiments, the axial thrust bearing arrangement includes a plurality of thrust surfaces corresponding to the plurality of adjustment members.

[0033] In some cases, instead of having a single axial thrust bearing arrangement, there may be multiple thrust surfaces corresponding to multiple regulating members. This may have the advantage of a smaller thrust surface, which reduces the cost and weight of the pump. Thrust surfaces may be expensive, with stringent requirements. Furthermore, where the portion of the bearing mounted to orbit with the orbiting scroll has reduced size and weight, this has a beneficial effect on the orbiting mass and the vibrations it generates.

[0034] In some embodiments, the plurality of thrust surfaces are substantially circular surfaces.

[0035] In some embodiments, the plurality of thrust surfaces are pivotally mounted on a member that contacts a central portion of each substantially circular surface.

[0036] Where there are separate thrust surfaces corresponding to each adjustment member, then their form may be circular, allowing the ball bearings to move in a circular motion as the orbiting scroll rotates. In some embodiments, the thrust surfaces may be mounted on a central member such as a central adjustment pin that allows pivoting, making the surfaces self-levelling and providing good ball contact and potentially longer bearing life.

[0037] In some embodiments, the axial thrust bearing device includes a plurality of modules corresponding to the plurality of adjustment members, each of the plurality of modules including a plurality of ball bearings mounted within a restriction member, the restriction member being configured to retain the ball bearings within the module while allowing each of the ball bearings to move along a circular path corresponding to the orbiting motion of the orbiting scroll portion.

[0038] In case the axial thrust bearing arrangement comprises a plurality of separate axial thrust surfaces mounted on axial adjustment members, the ball bearings may be mounted in a plurality of separate modules corresponding to each adjustment member, thereby reducing the size, weight and possibly the cost of the bearing arrangement.

[0039] In some embodiments, the restraint comprises at least one retainer comprising a plurality of circular recesses for retaining the plurality of ball bearings, the circular recesses having a larger diameter than the ball bearings such that the ball bearings can move along the circular path.

[0040] The ball bearings can be held in place by a restraint, which in some cases includes one or more retaining frames, and in some embodiments, each of the two retaining frames includes a plurality of circular recesses that retain the ball bearings within the module while allowing the ball bearings to move along the circular path required for relative orbital motion.

[0041] In some embodiments, the scroll vacuum pump includes a plurality of the receivers corresponding to the plurality of regulating members, each of the plurality of receivers includes the at least one surface and an orifice in the at least one surface.

[0042] Where there are a plurality of axial thrust bearings, there may be a receiver mounted around each axial thrust bearing and having a hole in a surface through which the adjustment member extends.

[0043] This arrangement also reduces the size and mass of the receiver that orbits with the scroll, thereby reducing bearing loads and generated vibrations.

[0044] In some embodiments, the plurality of adjustment members includes three adjustment members.

[0045] In order to provide accurate axial adjustment of the axial distance between the orbiting scroll and the fixed scroll, and also provide some control of the tilt and swing of the orbiting scroll, more than one axial adjustment member is required, and in many cases there are three adjustment members. The three adjustment members provide the required degrees of freedom to provide good and effective tilt and swing control without excessively increasing the number of required components. Therefore, in some embodiments, there are exactly three adjustment members. It is appropriate that they are spaced substantially equiangularly around the central axis, and in some embodiments, they are spaced between 100° and 140°, and in some cases substantially spaced 120°.

[0046] In some embodiments, the fixed scroll portion provides a central bore through which the drive shaft extends.

[0047] Embodiments are particularly suitable for scroll pumps in which the inlet vacuum space is on the orbiting scroll side of the pump. The inlet of the vacuum pump is connected to a chamber that is evacuated, and here it is particularly important to reduce contamination. Therefore, where there is contact between moving and stationary surfaces, being able to isolate these contact surfaces from the vacuum inlet space surrounded by the pump housing allows contamination from relative movement or from lubricants associated with the relatively moving surfaces to be suppressed, and a low contamination scroll pump is provided.

[0048] A second aspect provides a vortex pump, comprising:

[0049] an orbiting scroll portion; and

[0050] A fixed scroll portion;

[0051] a pump housing enclosing a pump chamber;

[0052] an axially extending drive shaft having an eccentric shaft portion on which the orbiting scroll portion is mounted so that rotation of the drive shaft imparts an orbiting motion to the orbiting scroll portion relative to the fixed scroll portion;

[0053] Axial thrust bearing device, comprising:

[0054] a plurality of ball bearing modules, each ball bearing module comprising a plurality of ball bearings, the plurality of ball bearing modules being mounted between the orbiting scroll portion and a plurality of thrust surfaces;

[0055] An adjusting mechanism, for adjusting the axial position of the plurality of thrust surfaces, and thereby adjusting the distance between the fixed scroll portion and the orbiting scroll portion, the adjusting mechanism comprising:

[0056] A plurality of adjustment members are angularly spaced about the drive shaft and each adjustment member is configured to independently adjust an axial position of a corresponding one of the plurality of thrust surfaces.

[0057] Embodiments can use multiple axial adjustment members to provide effective axial adjustment of the orbiting scroll portion so that the distance between the orbiting scroll portion and the fixed scroll portion can be accurately controlled. An axial thrust bearing device having a separate bearing module and a thrust surface associated with the bearing module and corresponding to the multiple axial adjustment members allows for reduced orbiting mass, facilitates sealing of the bearing cover, and provides a bearing, cover, and thrust surface of reduced size and therefore reduced cost.

[0058] In some embodiments, the plurality of thrust surfaces are substantially circular, and each thrust surface is mounted on a respective end of the plurality of adjustment members.

[0059] In some embodiments, the plurality of thrust surfaces are pivotally mounted on a member that contacts a central portion of the substantially circular surface.

[0060] In some embodiments, the plurality of ball bearings within each of the modules are mounted within a restraint configured to retain the ball bearings within the module while allowing each of the ball bearings to move along a circular path corresponding to the orbiting motion of the orbiting scroll portion.

[0061] In some embodiments, the restraint comprises at least one retainer comprising a plurality of circular recesses for retaining the plurality of ball bearings, the circular recesses having a larger diameter than the ball bearings such that the ball bearings can move along the circular path.

[0062] In some embodiments, the limiter comprises two cages, each of the two cages having a thickness between 60% and 99.9% of the radius of the ball bearing.

[0063] Where two cages are present, their thickness should be slightly less than the radius of the ball bearing. In some cases, between 60% and 99.9% of the radius of the ball bearing, allowing the ball bearing to extend beyond the cage and contact the surface while still remaining in place.

[0064] Further particular and preferred aspects are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with features of the independent claims as appropriate, and in combinations other than those explicitly set out in the claims.

[0065] Where an equipment feature is described as being operable to provide a function, it will be understood that this includes equipment features that provide that function or that are adapted or configured to provide that function. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Embodiments of the present invention will now be further described with reference to the accompanying drawings, in which:

[0067] Figure 1 A vortex pump according to one embodiment is shown;

[0068] Figure 2 An end view of a sealing and regulating member of an embodiment is shown;

[0069] Figure 3 shows a bearing module according to an embodiment; and

[0070] Figure 4 Shows Figure 3 Side view of the bearing module. DETAILED DESCRIPTION

[0071] Before discussing the embodiments in any greater detail, an overview will first be provided.

[0072] Embodiments provide a scroll pump, and in some cases, a scroll vacuum pump, having a precisely controlled axial thrust bearing to set the end clearance and thereby eliminating the need for end seals. The thrust bearing is located in the inlet vacuum space, and there may be a small bellows seal around each axial thrust bearing arrangement to isolate the lubricant from the inlet vacuum space.

[0073] An embodiment provides a set of three metal or polymer bellows to seal and isolate the axial thrust bearing and its adjustment system from the inlet space of the vacuum pump.

[0074] In an embodiment, a thrust bearing is mounted on the back of the orbiting scroll. A sealing cap or receiver is arranged on this bearing. The location where the adjusting member or screw passes through the cap and connects to the bearing is then sealed with a bellows that allows the cap to move in an orbiting motion with the scroll, while the part of the bearing held by the adjusting screw remains stationary.

[0075] In an embodiment, there are three adjustment screws and three bellows.The axial thrust bearing may be divided into three separate thrust bearings, each thrust bearing being individually sealed, or may be a single ring with three adjustment members or screws.

[0076] Using three bellows instead of a single large diameter bellows means that the bellows length can be shorter, which makes the pump shorter and, more importantly, less susceptible to differential thermal expansion of components and therefore maintains improved precise control of the thrust bearing and scroll-to-scroll axial clearance.

[0077] Where the thrust bearings are separate modules, separate non-orbiting thrust plates mounted on the adjustment member can be supported on a central adjustment pin, allowing pivoting and making them self-leveling, ensuring good ball contact and potentially better life.

[0078] This arrangement provides reduced orbiting mass, thereby reducing pump vibrations. In addition, with this modular arrangement, sealing the bearing caps may be easier and the bearing components and caps are smaller, which reduces costs.

[0079] Figure 1 A scroll pump 10 is shown according to one embodiment. The scroll pump 10 includes an orbiting scroll 30 mounted on an eccentric cam portion 44 of a rotatable drive shaft 42. The drive shaft 42 is driven by a motor 60, and during use, rotation of the drive shaft 42 imparts an orbiting motion to the orbiting scroll 30 relative to the fixed scroll 32. This orbiting motion pumps fluid along a fluid flow path between a pump inlet located near the edge of the scroll toward a pump outlet near the center.

[0080] In this arrangement, the fixed scroll 32 includes an opening through which the drive shaft 42 extends. The motor 60 that drives the drive shaft is located on the fixed scroll side of the pump. The inlet vacuum region is located on the right hand side of the figure away from the motor and bearings. A lower vacuum or atmospheric pressure region is located on the outlet side of the pump toward the motor.

[0081] The drive shaft 42 is sealed from the inlet vacuum space defined by the pump housing 40 by a cover 50. Because the drive shaft 42, drive motor 60 and associated bearings for mounting the drive shaft 42 are located on the discharge side of the scroll pump, contaminants from any lubricant associated with these components are isolated to some extent from the fluid being pumped solely in the direction of flow of that fluid.

[0082] However, in this embodiment there are axial thrust bearings 15 which themselves contain lubricant within the inlet vacuum region. These provide control of the axial position of the orbiting scroll and therefore control of the clearance between the scrolls. If contamination by lubricant is to be inhibited, these axial thrust bearings 15 themselves should be isolated to some extent from the inlet vacuum region.

[0083] The axial thrust bearing 15 comprises axial adjustment members 12 which extend outwardly through the wall of the pump housing 40, thereby allowing access to the adjustment members so that their axial length and therefore the gap between the vortex portions can be adjusted. These axial adjustment members 12 abut against a thrust surface 16 which, in this embodiment, has an annular shape extending around the central axis of the orbiting vortex portion 30. The thrust surface 16 is pushed by the adjustment members against the ball bearings 14 of the axial thrust bearing 15, which in turn push against the orbiting vortex portion 30. Thus, by adjusting the length of the adjustment members 12, the gap distance between the vortex portion plates can be controlled.

[0084] In this embodiment, there are three adjustment members 12, which can each be adjusted independently, thereby allowing not only the gap distance to be changed, but also any wobble or tilt associated with the orbiting scroll to be reduced. The ball bearings 14 are held in place by retaining rings 18 extending on either side of the ball bearings 14, which follow a circular path as the orbiting scroll orbits. A further thrust surface is mounted on the orbiting scroll plate against which the ball bearings abut. In this way, any wear on the orbiting scroll plate from the movement of the ball bearings is reduced.

[0085] In order to suppress any leakage of lubricant from the axial thrust bearing to the chamber defined by the pump housing 40 and the fixed scroll portion 32, the axial thrust bearing 15 and the regulating member 12 are enclosed in sealing devices 20, 22. These sealing devices include an annular receiving member or cover 20 having holes corresponding to a plurality of regulating members 12. These receiving members are fixedly mounted on the rear of the orbiting scroll plate. The sealing device also includes a bellows 22, which is configured to extend from the receiving member 20 and seal to the receiving member surface around the hole. The bellows 22 extends from the surface of the receiving member to the end wall of the pump housing 40 surrounding the regulating member 12. The bellows is sealed to the inner surface of the end wall 40 around the hole through which the regulating member passes. In this way, the sealing devices 20, 22 are sealed to the surface in a fixed manner, and the relative movement between the orbiting scroll portion and the end wall of the pump housing is absorbed by the flexibility of the wall of the bellows 22.

[0086] Although in this embodiment the flexible portion of the sealing means comprises a bellows 22, in other embodiments other flexible means may be used to provide the flexible portion of the sealing means. An advantage of a bellows means is that it dampens the rotational movement of the orbiting scroll.

[0087] By providing a separate sealing device to surround each of the separate adjustment members of the axial thrust bearing arrangement, the diameter of the sealing device and the length associated with the diameter can be significantly smaller than if the entire axial thrust bearing arrangement were enclosed in a single sealing device. This allows the production of a smaller pump and thereby reduces thermal differences within the pump, allowing greater precision in the axial control of the scroll position.

[0088] Figure 2 Shows Figure 1 End view of a vortex pump without a housing 40. In this embodiment, there is a single axial thrust bearing having an annular shape and a corresponding annular receiver 20. There are three adjusting members 12, which extend through holes in the surface of the receiver 20, which face away from the orbiting vortex portion. Each adjusting member 12 is surrounded by a sealing device 22 in the form of a bellows, which is sealed to the surface of the receiver 20 around the hole, and the adjusting member 12 extends through the hole and extends upward to the housing 40 of the pump (not shown), and is sealed to the housing. In this way, the thrust bearing in the adjusting member 12 and the receiver 20 is isolated from the vacuum inlet space in the pump housing. The sealing member 22 is flexible, and this allows the portion that contacts the receiver 20 to orbit with the receiver, while the other end of the sealing device 22 is attached to the housing 40 and does not move. In some embodiments, the orbiting motion causes the ball bearing to follow a circular path with a diameter between 1 mm and 9 mm, while the diameter of each bellows is between 30 mm and 150 mm, and the length is between 30 mm and 160 mm.

[0089] Figure 3 An alternative embodiment bearing module 80 is shown in which, instead of having a single annular axial thrust bearing, there are a plurality of individual axial thrust bearings corresponding to a plurality of adjustment members. Each adjustment member has a thrust surface on an end face which contacts a ball bearing 14 within a separate bearing module 80 which in turn contacts a thrust surface on the orbiting scroll.

[0090] In this embodiment, there are seven ball bearings 14 located within the cage 70, but there may be a different number, such as if there is no central ball bearing, then there are six ball bearings located within the cage 70. The cage 70 has a recess 72 in which the balls can move. The recess 72 is configured to be large enough to accommodate the balls moving along a circular path that allows the balls to follow the orbiting motion of the scroll.

[0091] Figure 4A side view of a bearing module 80 is shown together with a thrust plate 82 mounted on an adjusting member. The thrust plate 82 is supported on a center pin (not shown) that allows the plate to pivot so that the thrust plate 82 is self-leveling and ensures good ball contact and potentially longer bearing life. There is another thrust plate 84 that is connected to the orbiting scroll and is configured to orbit with the scroll. The bearing module 80 includes two retainers 70, one mounted on the thrust plate 82 on the adjusting member and the other mounted on the thrust plate 84 on the orbiting scroll. Between the two retainers 70 are the ball bearings 14. The retainers 70 are configured so that their thickness is less than the radius of the ball so that the ball 14 contacts the thrust plate. The thickness can be only slightly less, and in some embodiments, they are between 70% and 99.9% of the radius of the ball 14. For example, the ball bearing may have a diameter of 8 mm, a radius of 4 mm, and the cage may have a thickness of 3.99 mm, resulting in a cage to radius ratio of 99.75%.

[0092] Providing a separate bearing module 80 rather than an annular bearing allows the thrust plate to be smaller and therefore have lower orbiting mass, which reduces pump mass and vibration. This also potentially allows easier sealing of the bearing caps. Furthermore, all bearing components, caps and thrust surfaces will be smaller, which reduces cost.

[0093] Although illustrative embodiments of the present invention have been disclosed in detail herein with reference to the accompanying drawings, it should be understood that the invention is not limited to the precise embodiments and that various changes and modifications may be implemented therein by those skilled in the art without departing from the scope of the invention as defined by the appended claims and their equivalents.

[0094] Reference numerals

[0095] 10 Vortex Pump

[0096] 12 Adjustment components

[0097] 14 Ball bearings

[0098] 15 Axial thrust bearing

[0099] 16, 80, 84 thrust plate

[0100] 18 Retaining ring

[0101] 20 Acceptance

[0102] 22 Sealing device

[0103] 30 Orbiting scroll

[0104] 32 Fixed scroll

[0105] 42 Drive shaft

[0106] 44 Cam

[0107] 50 caps

[0108] 60 Motor

[0109] 70 Cage

[0110] 72 recess

[0111] 80 Bearing modules.

Claims

1. A scroll vacuum pump, comprising: orbiting scroll portion; as well as A fixed scroll portion; a pump housing enclosing a pump chamber of the scroll vacuum pump; an axially extending drive shaft having an eccentric shaft portion on which the orbiting scroll portion is mounted so that rotation of the drive shaft imparts an orbiting motion to the orbiting scroll portion relative to the fixed scroll portion; an axial adjustment mechanism for adjusting the axial position of the orbiting scroll portion and thereby adjusting the distance between the fixed scroll portion and the orbiting scroll portion, the axial adjustment mechanism comprising a plurality of adjustment members angularly spaced about the drive shaft and extending through the pump housing toward the orbiting scroll portion, the plurality of adjustment members each being configured to provide an independently adjustable axial position of the orbiting scroll portion; as well as A plurality of sealing devices are used to isolate the plurality of regulating members from the pump chamber, the plurality of sealing devices extending around each of the plurality of regulating members and including at least one flexible portion so that one end of the sealing device can orbit relative to another fixed end of the sealing device.

2. The scroll vacuum pump according to claim 1, wherein: The plurality of sealing devices each include a bellows.

3. The scroll vacuum pump according to claim 1 or 2, wherein The plurality of seals are each attached at one end to the pump housing and at another end to at least one surface that orbits with the orbiting scroll.

4. The scroll vacuum pump according to claim 3, wherein The axial adjustment mechanism comprises an axial thrust bearing device, and the axial thrust bearing device comprises: a plurality of ball bearings mounted between the orbiting scroll portion and at least one thrust surface; as well as The plurality of adjustment members are each configured to independently adjust an axial position of the at least one thrust surface.

5. The scroll vacuum pump according to claim 4, wherein: The at least one thrust surface is mounted such that a radial center point of the at least one thrust surface is between 30% and 80% of a radius of the orbiting scroll portion.

6. The scroll vacuum pump according to claim 4, wherein: The at least one thrust surface includes an annular thrust surface facing the orbiting scroll and extending around a central axis of the orbiting scroll.

7. A vortex vacuum pump according to any one of claims 4 to 6, further comprising at least one receiving member mounted on the orbiting vortex portion, the at least one receiving member surrounding the ball bearing and including the at least one surface, the plurality of adjusting members each extending through corresponding holes in the at least one surface, the other ends of the plurality of sealing members being sealed to the at least one surface around the plurality of holes.

8. The scroll vacuum pump according to claim 6, further comprising at least one receiving member mounted on the orbiting scroll portion, the at least one receiving member surrounding the ball bearing and including the at least one surface, the plurality of adjustment members each extending through a corresponding hole in the at least one surface, the other ends of the plurality of sealing members being sealed to the at least one surface around the plurality of holes, wherein The receiver has an annular shape and is configured and installed to surround the annular thrust surface, and the at least one surface includes a single annular surface and includes a plurality of holes at positions corresponding to the plurality of adjustment members.

9. The scroll vacuum pump according to claim 7, wherein: The axial thrust bearing device includes a plurality of thrust surfaces corresponding to the plurality of adjustment members.

10. The scroll vacuum pump according to claim 9, wherein: The axial thrust bearing device includes a plurality of modules corresponding to the plurality of adjustment members, each of the plurality of modules including a plurality of ball bearings mounted in a restriction member, the restriction member being configured to retain the ball bearings within the module while allowing each of the ball bearings to move along a circular path corresponding to the orbiting motion of the orbiting scroll portion.

11. The scroll vacuum pump according to claim 9, comprising a plurality of the receivers corresponding to the plurality of regulating members, each of the plurality of receivers comprising the at least one surface and a hole in the at least one surface.

12. The scroll vacuum pump according to claim 1 or 2, wherein: The plurality of adjustment members includes three adjustment members.

13. The scroll vacuum pump according to claim 1 or 2, wherein the fixed scroll portion includes a central hole, and the drive shaft extends through the central hole.

14. The scroll vacuum pump according to claim 2, wherein: The bellows is formed from at least one of a metal and a polymer.

15. The scroll vacuum pump according to claim 4, wherein: The at least one thrust surface is mounted on ends of the plurality of adjustment members.

16. The scroll vacuum pump according to claim 9, wherein: The plurality of thrust surfaces are circular surfaces.

17. The scroll vacuum pump according to claim 10, wherein: The restrictor includes at least one retainer including a plurality of circular recesses for retaining the plurality of ball bearings, the circular recesses having a larger diameter than the ball bearings so that the ball bearings can move along the circular path.

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