Scroll vacuum pump and method of operating scroll vacuum pump

Abstract

To improve a scroll vacuum pump so that an accurate axial gap size is given.SOLUTION: A scroll vacuum pump that comprises a pump system which has a fixed spiral component 11 and a movable spiral component 13 interacting with the fixed spiral component to perform pumping operation, a drive shaft 17 which is for driving the movable spiral component, and has an eccentric part 19 and rotates on an axis 15 of rotation in operation, and electric drive motors 21, 23 for the drive shaft is provided with adjustment means configured to adjust an axial gap size present between both spiral components.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] SUMMARY The present disclosure relates to improvements in scroll vacuum pumps and methods of operating scroll vacuum pumps.

[0002] In this case, the scroll vacuum pump comprises a pump system having a fixed spiral element and a movable spiral element which interacts with the fixed spiral element to provide a pumping action, a drive shaft which has an eccentric portion and rotates about a rotation axis during operation for driving the movable spiral element, and an electric drive motor for the drive shaft. [Background technology]

[0003] Scroll vacuum pumps are known in principle, for example from EP-A-3153708, EP-A-3617511, EP-A-3647599, EP-A-4174285 and EP-A-4253720.

[0004] A scroll pump is a positive displacement pump that compresses against atmospheric pressure and can be used, among other things, as a compressor. A scroll vacuum pump can be used to create a vacuum in a recipient connected to the inlet of the scroll vacuum pump.

[0005] Scroll vacuum pumps are also called spiral vacuum pumps or spiral pumping devices.The pumping principle on which scroll vacuum pumps are based is basically known from the prior art and will therefore only be briefly described below.

[0006] Typically, the pumping system of a scroll vacuum pump has spiral cylinders, also referred to simply as spirals, for example, Archimedes' spirals, which engage or nest with one another. In this case, each spiral cylinder has at least one spiral wall, which has a support, particularly in the form of a plate, provided on its end face. In this case, the outer turns of the spiral cylinder, for example, two or three outer turns of the spiral cylinder, can be formed by wall sections each having a fixed circumferential distance from the center point of the spiral. Even if these wall sections do not strictly speaking form spiral sections but circular arcs, the wall sections are still added to the spiral and are referred to as spiral turns in the context of the present disclosure.

[0007] In this case, the spiral cylinders are nested within one another so that the two spiral cylinders partially enclose a half-moon or crescent-shaped volume (pumping space). One of the two spirals is stationary or fixedly arranged in the pump housing, while the other spiral, together with its support, can move on a circular path via an eccentric part of the drive shaft. This spiral, together with its support, is therefore also called an orbital. The moving spiral part thus performs a so-called centrosymmetric oscillation, also called an "orbital movement" or "oscillation." The half-moon-shaped volume (pumping space) formed between the spiral cylinders gradually shifts inward during the orbital movement of the moving spiral part within the spiral. Due to this change in volume, the process gas to be pumped is pumped from the inlet port of the pump system, located radially outward, to the outlet port of the pump system, located, in particular, at the spiral center, radially inward.

[0008] The eccentric drive, i.e., the drive shaft with an eccentric portion, is located in the housing of the scroll vacuum pump on the side of the support facing away from the orbital spiral. In practice, it is often surrounded by a deformable sleeve, e.g., a corrugated bellows, which serves, on the one hand, to seal the drive from the suction area and, on the other hand, to prevent rotation of the orbital, since the orbital would otherwise rotate without the anti-rotation device. To ensure this prevention, for example, the deformable sleeve can be connected at its first end to the support, while its second end, opposite the first end, can be screwed to the housing base within the housing by multiple fastening means. The deformable sleeve (e.g., a corrugated bellows) has a permanent sealing effect and thus seals against the pump housing and the moving spiral part.

[0009] The structural group comprising the orbital and the deformable sleeve (e.g., a corrugated bellows) can be preassembled during pump assembly, so that the structural group can then be inserted into the pump housing as a unit, and the aforementioned second end of the deformable sleeve can be screwed to the housing base using a fastening means. Typically, the spiral wall of the movable spiral element and the spiral wall of the fixed spiral element are each provided with a separate sealing element on their end faces facing away from the support; these separate sealing elements are also called tip seals in the field of scroll vacuum pumps. The tip seal, usually made of plastic, serves to seal the volume enclosed by the aforementioned spiral wall and is therefore particularly important for the vacuum capacity of the scroll vacuum pump.

[0010] However, there are drawbacks associated with tip seals. Tip seals have a limited lifespan and therefore must be replaced periodically, which increases the maintenance effort of the scroll vacuum pump. Furthermore, tip seals are subject to wear. Furthermore, tip seals are sensitive to certain external influences, such as radiation, to which the scroll vacuum pump may be exposed in certain applications.

[0011] Scroll vacuum pumps without tip seals in the spiral wall are known, but require extremely precise relative orientation between the fixed and movable spiral components to maintain a precisely defined axial gap dimension relative to the rotation axis between the end face of the spiral wall of one spiral component and the so-called groove bottom or spiral bottom (hereinafter simply referred to as the spiral bottom) of the other spiral component, i.e., the side of the support facing it. To achieve this dimensioning, an axial gap dimension in the range of 10 μm to 30 μm is required for an acceptable vacuum capacity, and it should be clearly stated here that even a slight axial gap dimension, i.e., a few micrometers larger, can result in a significant deterioration of the vacuum capacity. Furthermore, it should be noted that both axial gap dimensions can be the same or different, i.e., the axial gap dimension between the spiral wall end face of the orbital and the groove bottom of the spiral housing, on the one hand, and the axial gap dimension between the spiral wall end face of the spiral housing and the groove bottom of the orbital, on the other hand, can be the same or different from each other.

[0012] In scroll vacuum pumps with tip seals, the exact axial clearance dimension plays a less important role, since the tolerances regarding the relative orientation between both spiral parts can be compensated for, at least to some extent, by the tip seal.

[0013] In view of a unified definition, within the scope of the present disclosure, even if a sealing element (tip seal) is provided on the spiral wall, the axial gap dimension is understood to be the gap dimension between the end face of the respective spiral wall of one spiral part and the groove bottom of the other spiral part, i.e. in this case the axial gap dimension is not understood to be the gap dimension with respect to the end face of the sealing element, but equally the gap dimension with respect to the end face of the spiral wall on which the sealing element is provided.

[0014] A scroll vacuum pump without tip seals but at the same time having a sufficiently high vacuum capacity is not only advantageous in that it requires less maintenance, there is no longer any wear, and it is not sensitive to certain external influences, but also leads to a constant vacuum capacity over time for the scroll vacuum pump, since in the absence of tip seals there are no longer any components that, on the one hand, contribute significantly to the vacuum capacity, but at the same time, are subject to wear on the other hand.

[0015] Scroll vacuum pumps without tip seals can therefore also be used in such applications, which is particularly advantageous in practice where a vacuum capacity that is as constant as possible over time is important rather than a high vacuum capacity.

[0016] Against this background, it has become clear that scroll vacuum pumps without tip seals and with precisely defined axial clearance dimensions could develop new markets. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] European Patent Application Publication No. 3153708 [Patent Document 2] European Patent Application Publication No. 3617511 [Patent Document 3] European Patent Application Publication No. 3647599 [Patent Document 4] European Patent Application Publication No. 4174285 [Patent Document 5] European Patent Application Publication No. 4253720 Summary of the Invention [Problem to be solved by the invention]

[0018] The object of the present invention is to improve a scroll vacuum pump of the type mentioned at the beginning in such a way that precise axial clearance dimensions are provided. [Means for solving the problem]

[0019] This problem is solved by various aspects of the present invention. The aspects of the present invention disclosed below may be combined with one another in any manner, provided they are not mutually inconsistent. These aspects are further developments of the aspects defined in the claims and described in the following description (including the description of the drawings), and these developments are also referred to as embodiments or examples. In this case, each development of one aspect may be combined with other aspects and developments of other aspects in any manner, provided they are not mutually inconsistent.

[0020] Unless expressly stated otherwise, in each disclosed embodiment, the scroll vacuum pump may include a controller configured to perform the functions required for each concept of adjusting the axial clearance size, and may be integrated with or separate from the controller that controls the actual pumping operation of the scroll vacuum pump, but in this case configured to communicate with the controller that controls the pumping operation.

[0021] According to a first aspect of the invention, an axial gap dimension exists between both spiral parts, and adjustment means are provided that are configured to adjust the axial gap dimension.

[0022] The adjusting means makes it possible to accurately define the axial spacing dimension, i.e., the axial spacing between the end face of the spiral wall and each spiral bottom relative to the rotation axis of the drive shaft that rotates during operation.

[0023] As already mentioned at the beginning, the fixed spiral part is also called the spiral housing, and the moving spiral part is also called the orbital.

[0024] "Adjusting" the axial clearance dimension also includes "holding" the axial clearance dimension at a target value. The target value can be set for the respective application, for example, by the scroll vacuum pump manufacturer, or can be set, i.e., individually selected, by the scroll vacuum pump user. Such "holding" of the axial clearance dimension can involve a change in the axial clearance dimension when deviations from the respective target value occur during pump operation, for example, due to thermal effects or other reasons, resulting in a required change.

[0025] "Adjusting" the axial clearance dimension also includes "changing" the axial clearance dimension in terms of changing the target value. Such a change may be required, for example, when a different amount of axial clearance is needed for various operating conditions or applications.

[0026] "Adjustment" of the axial gap dimension also includes means that allow one or both spiral parts to adjust itself, e.g., in terms of "alignment," especially after the run-in period of the scroll vacuum pump, and thus to adjust the relative position between both spiral parts. Within the scope of this disclosure, when run-in is mentioned, e.g., in terms of grinding fit, this should be understood to include the running-in of sealing elements (tip seals) present on the end faces of the spiral walls, even if the presence of sealing elements is not explicitly mentioned in the respective connection.

[0027] The term "adjustment means" should be interpreted broadly and may include "passive" means, such as a particular combination of materials, a particular coefficient of thermal expansion, a particular rate of heat release in a component or part of a component of the scroll vacuum pump, or a combination of different coefficients of thermal expansion or particular rates of heat release.

[0028] An "active" adjusting means may, for example, comprise a unit having at least one component or structure and an assigned control device, the component or structure being appropriately actuated and controlled to achieve the desired adjusting action.

[0029] In some embodiments, it may be contemplated that the adjustment means may be configured to adjust the axial clearance dimension when the pump is not in operation. The axial clearance dimension may be adjusted once, for example, during assembly of the scroll vacuum pump. This is also referred to as initial axial clearance adjustment. Alternatively or additionally, the adjustment means may be configured to allow the axial clearance dimension to be adjusted in specific situations, for example, during maintenance of the scroll vacuum pump or in preparation for a new application. Adjustment of the axial clearance dimension may be performed, for example, manually.

[0030] In some embodiments, it may be contemplated that the adjustment means is configured to adjust the axial clearance dimension during pump operation.

[0031] The adjustment can be done manually, for example.

[0032] In another embodiment, the adjustment can be performed within the scope of control. In particular, in such a control, the axial gap dimension is the controlled variable, whose actual value is continuously measured and compared with a target value, possibly depending on one or more variables. The adjustment value that influences the axial gap dimension can be various. For example, the rotation speed of the fan can be used as an adjustment value, since the fan speed influences the heat transport in the pump, and more or less heat reaches certain components or parts of components, the thermal expansion of which must be influenced by the fan, thereby applying a corresponding mechanical load to the moving spiral part, and thus influencing the axial gap to be appropriately adjusted.

[0033] The above control examples are intended only to provide an exemplary and illustrative illustration of how the axial clearance dimension can be adjusted within a range of control during pump operation.

[0034] If the adjustment means is suitably configured, manual adjustments can also be made while the pump is running, where "manual" includes any kind of actuator actuation or displacement, both manually without tools and with tools.

[0035] According to some embodiments, the adjusting means may provide for applying a load to one of the two spiral parts, in particular to the movable spiral part or to both spiral parts. In this case, the load is applied in particular mechanically. The mechanical load may be applied directly or indirectly, where indirect mechanical load is understood to mean that the corresponding spiral part is loaded via another part.

[0036] In other words, the application of a load is an active means of adjusting the axial gap size, which should be understood as distinct from passive means such as selecting materials with different thermal expansion coefficients.

[0037] The application of a load, in particular a mechanical load, to one of the two spiral parts, in this case in particular the moving spiral part, can be achieved by taking advantage of the situation where the support of the moving spiral part on the eccentric part of the drive shaft allows for a certain degree of axial mobility. The support of the moving spiral part can be achieved, for example, by means of a rolling bearing. In particular, so-called flange bearings are used to support the moving spiral part on the eccentric part of the drive shaft. Alternatively, the support can be achieved by means of a separate ball bearing.

[0038] According to some embodiments, it can be provided that the adjustment means is configured to apply a load to one spiral part or to both spiral parts, in particular at one point located on the axis of rotation and / or at multiple points, in particular distributed around the axis of rotation.

[0039] According to a further embodiment, the adjusting means may be configured to influence the relative axial orientation between both spiral parts with respect to the axis of rotation.

[0040] Furthermore, according to some embodiments, the adjustment means may be configured to move one of both spiral parts, in particular the movable spiral part, or both spiral parts axially or tilt them relative to the axis of rotation.

[0041] According to some embodiments, a measuring device may be provided that is configured to measure the axial clearance dimension at one or more locations, particularly continuously during pump operation.

[0042] For example, the axial gap dimension can be measured directly by determining the size of the respective axial gap between the end face of the spiral wall of one spiral part and the bottom, i.e., spiral bottom, of the other spiral part. Alternatively, the axial gap dimension can be measured directly by determining the value of another quantity that can be used as the axial gap dimension, for example the value of the axial distance between the pump housing and a part of the movable spiral part, for example the bottom, i.e., the groove bottom or the back surface of the support of the movable spiral part.

[0043] Since the measurement of the axial gap dimension does not only involve the determination of a single value, but also allows for the determination of several values ​​at different locations, the tilted orientation of one or both of the two spiral parts itself can also be recognized or quantitatively determined. In other words, the measurement of the axial gap dimension also involves the measurement of the tilted orientation of one or both spiral parts. In this case, a tilted orientation is understood to be an orientation of the respective spiral part in which the central axis of the respective spiral part and therefore its spiral wall does not extend exactly parallel to the rotational axis of the drive shaft.

[0044] The measuring device may comprise at least one contactless distance sensor, for example an eddy current sensor, which may be a component of an adjustment device, for example an active magnetic bearing.

[0045] As mentioned at the beginning, the present invention is particularly advantageous for scroll vacuum pumps that do not have tip seals. Therefore, according to some embodiments, it is provided that the spiral wall of the movable spiral part and the spiral wall of the fixed spiral part each do not have a separate sealing element, i.e., a tip seal, on their end faces facing away from the spiral base.

[0046] In principle, the ability to adjust the axial gap between two spiral components can be advantageous even when a tip seal is present. Therefore, in some embodiments, it may be contemplated that the spiral wall of the movable spiral component and the spiral wall of the fixed spiral component are each provided with a separate sealing element at the end face facing away from the spiral base. The ability to adjust the axial gap size in a scroll vacuum pump with a tip seal can be advantageous, for example, to result in less or more uniform wear of the tip seal. The adjustment of the axial gap size may be or may include alignment of the spiral components, for example, to compensate for tilt or runout. This is also advantageous for less or more uniform wear of the tip seal.

[0047] In some embodiments of the invention, a hybrid configuration is also conceivable, i.e., the spiral wall of one spiral part does not have a separate sealing element on its end face facing away from the spiral groove, and the spiral wall of the other spiral part has a separate sealing element on its end face facing away from the spiral groove. In this case, both configurations are conceivable, i.e., the fixed spiral part may have a tip seal, whereas the movable spiral part may not have a tip seal, or vice versa.

[0048] A second aspect of the present invention relates to a method of operating a scroll vacuum pump comprising a pump system having a fixed spiral element and a movable spiral element interacting with the fixed spiral element to provide a pumping action therewith; a drive shaft having an eccentric portion for driving the movable spiral element, the drive shaft rotating about a rotational axis in operation; and an electric drive motor for the drive shaft, the method including adjusting an axial gap dimension between both spiral elements.

[0049] As previously mentioned, adjustment of the axial clearance dimension, including "holding" and "varying," can be made during pump operation, particularly within the range of control, for example, as previously described.

[0050] Operation of a scroll vacuum pump also includes start-up of the scroll vacuum pump or of a vacuum system including the scroll vacuum pump, e.g., a pump stand; i.e., operation of the pump also includes adjustment of the axial clearance dimension outside of pump operation, e.g., once upon assembly of the pump and / or in preparation for a specific situation or new application, such as within the scope of maintenance.

[0051] According to some embodiments of the first and second aspects, it may be envisaged that there is an axial displacement between the motor rotor and the motor stator of the drive motor, whereby an axial force acting on the motor rotor is generated during operation of the drive motor, in which case a drive shaft is connected to the motor rotor, whereby the axial force is transmitted to the drive shaft, and in which case a control device is provided for the drive motor, and by the control device the drive motor can be operated and controlled to vary the magnitude of the axial force.

[0052] This unit having an axial displacement between the motor rotor and the motor stator of the drive motor and having a control configured to vary the axial force is a development of the first aspect (scroll vacuum pump), while this method of controlling the drive motor to vary the axial force is a development of the second aspect (method).

[0053] By appropriate control of the drive motor, including in particular appropriate energization, the force acting axially on the drive shaft and thus the force that the drive shaft exerts on the moving spiral part can be precisely adjusted, and thus the axial gap dimension can be adjusted as desired in each case.

[0054] This concept for generating axial forces is known per se in connection with drive motors for scroll vacuum pumps (EP 3153708 A1), but its use for adjusting the axial clearance dimension is not known.

[0055] According to a third aspect of the invention, in a scroll vacuum pump of the type mentioned at the beginning, adjustment means are provided, which are configured to adjust the axial gap between the two spiral parts, and the adjustment means comprises at least one active magnetic bearing for the moving spiral part.

[0056] By active magnetic bearings we understand magnetic bearings which are able to generate a variable bearing force by means of controlled electromagnets.

[0057] The magnetic bearing may be arranged, for example, on the rear surface of the moving spiral part, where rear surface is understood to mean the surface facing away from the fixed spiral part.

[0058] The magnetic bearing may comprise a sensor, in particular an eddy current sensor, by means of which the axial gap dimension can be measured, which may be constructed or arranged so that the axial gap dimension can be measured directly or indirectly by determining the value of another quantity that can be used as the axial gap dimension, for example the value of the axial spacing between the pump housing and part of the moving spiral part.

[0059] According to a fourth aspect of the invention, in a scroll vacuum pump of the type mentioned at the beginning, adjusting means are provided, which are configured to adjust the axial gap between the two spiral parts, and in which a corrugated bellows is provided between the movable spiral part and the pump housing, and the adjusting means are configured to vary the pressure in the corrugated bellows.

[0060] As mentioned above, corrugated bellows are essentially known as components of scroll vacuum pumps. In this aspect of the invention, the corrugated bellows form part of the regulating means.

[0061] By varying the pressure in the corrugated bellows, a mechanical load of varying magnitude is applied to the moving spiral element, which, as already mentioned elsewhere, makes use of the fact that the bearing of the moving spiral element, for example by a flange bearing configured as a rolling bearing, allows for a small movement of the moving spiral element in the axial direction.

[0062] The adjusting means may comprise at least one pressure sensor and a valve unit in the corrugated bellows. The pressure sensor can be used to measure the pressure in the corrugated bellows and / or in the pump housing. In particular, the pressure measurement using the pressure sensor is performed in the suction region of the scroll vacuum pump. The valve unit may comprise, for example, a solenoid valve. The pressure in the corrugated bellows can be varied, for example, by a valve unit located at the connection between the suction region of the scroll vacuum pump and the corrugated bellows or at the connection between the pumping structure, in particular a point between the spiral walls of the spiral part, and the corrugated bellows.

[0063] If the pressure measurement by means of a pressure sensor takes place in the suction region of a scroll vacuum pump, this takes place in particular in the region of the pump housing outside the corrugated bellows, in the suction region of the pump housing or in the suction region of the fixed spiral part.

[0064] According to a fifth aspect of the invention, a scroll vacuum pump of the type mentioned at the outset has adjusting means adapted to adjust the axial gap dimension existing between both spiral parts, the adjusting means being adapted to vary the preload of the drive shaft, the rotary bearing of the drive shaft or the bearing sleeve of the drive shaft.

[0065] Each of the means for creating a preload forms a component of the adjustment means.

[0066] According to some embodiments, the adjustment means comprises a length-variable device supported on a receiving part, in particular on the rotor of the drive motor, and adapted to apply a mechanical load to the drive shaft directly or indirectly in the axial direction relative to the axis of rotation, for example via a rotation bearing of the drive shaft.

[0067] In these embodiments it is therefore possible to vary the axial extent of the length-variable device relative to the axis of rotation. The length-variable device may for example be a spring unit, such as a wave spring, a fluid-loadable elastic element or an element made at least in part from a bimetal.

[0068] According to a sixth aspect of the present invention, in a scroll vacuum pump of the type mentioned at the beginning, adjustment means are provided, which are configured to adjust the axial gap between both spiral parts, and the adjustment means comprises at least one actuator, preferably a piezo actuator, which is configured to apply a load axially relative to the axis of rotation to the fixed spiral part or to the movable spiral part, directly or indirectly.

[0069] In this case, it may be envisaged in particular that the actuator is arranged between both spiral parts, between the fixed spiral part and the pump housing, between the movable spiral part and the pump housing, or between the receiving part and the drive shaft or a part connected to the drive shaft.

[0070] Such an actuator allows a mechanical load to be applied to the fixed or movable spiral element, thereby making it possible to use a certain degree of slight axial mobility of the movable spiral element to adjust the axial gap dimension as desired in each case.

[0071] According to some embodiments, it may be provided that the adjustment means comprises a plurality of actuators distributed around the axis of rotation. In this case, the plurality of actuators may be uniformly distributed around the axis of rotation. For example, three actuators may be provided, each with an angular interval of 120°.

[0072] By controlling the actuator differently, the movable spiral element can be tilted relative to the axis of rotation, if the bearing of the movable spiral element and the point at which the actuator acts directly or indirectly on the movable spiral element allow such tilting in principle, thereby compensating for, for example, a tilted position due to tolerances or an axial runout of the spiral element due to tolerances.

[0073] The control device of the scroll vacuum pump can control these actuators together or independently of one another, thereby changing the axial distance between the pump housing and the spiral housing and thus adjusting the axial clearance between the spiral housing and the orbital. The inclination of the spiral housing relative to the pump housing can also be corrected by appropriately controlling the circumferentially distributed actuators differently.

[0074] According to a seventh aspect of the present invention, in a scroll vacuum pump of the type mentioned at the beginning, adjusting means are provided, which are configured to adjust the axial gap dimension existing between both spiral parts, and wherein the adjusting means are configured to actively or passively influence the thermal expansion of at least one part occurring during pump operation and / or the adjusting means are configured to influence the heat transport within the pump.

[0075] Within the scope of this disclosure, heat transport is also understood as heat radiation, ie the absorption of heat or the dissipation of heat by heat radiation.

[0076] When the thermal expansion of a part is influenced, this part forms part of the adjusting means. When the heat transport is influenced, the influencing means or means form part of the adjusting means.

[0077] Components that can be affected by thermal expansion are, for example, components that directly or indirectly influence the axial orientation of the moving spiral element. These components may be, for example, a pump housing, a drive shaft, a rolling bearing, an inner ring of a rolling bearing, an outer ring of a rolling bearing, a bearing sleeve, or an adapter sleeve. Within the scope of the present disclosure, an adapter sleeve is a sleeve-like part in the pump housing or in or on the drive shaft, for example, in which one or more bearings are located or on the drive shaft.

[0078] According to some embodiments, it may be provided that the adjusting means is provided and at least one part of the component is made of a material having a thermal conductivity of more than 100 W / mK. In particular, materials other than steel may be used. Alternatively or additionally, it may be provided that the component has at least one first part and at least one second part, in which case the adjusting means is provided and both parts are made of materials having different thermal conductivities. The mentioned material or a material with a higher thermal conductivity may be, for example, aluminum bronze.

[0079] According to some embodiments, it may be provided that the component has at least a first part and at least one second part, in which case the adjustment means are provided, both parts having different thermal expansion coefficients, in particular one of these parts having a negative thermal expansion coefficient.

[0080] Due to the fact that some of the components differ from one another in terms of their thermal expansion coefficients, the thermal expansion of the components that occurs during pump operation can be at least partially compensated for. Since all of the properties of the scroll vacuum pump components are essentially known, the thermal properties of the components during pump operation are also essentially known, i.e., predictable, so that the thermal expansion of the components can be predicted and therefore at least partially compensated for by appropriate material combinations.

[0081] According to some embodiments, it may be provided that the adjusting means comprises a heating device and / or a cooling device, the heating device and / or the cooling device being configured to apply a thermal load directly or indirectly to at least one region of the component.

[0082] For example, one or more so-called "heat pipes" (also called heat collectors) may be provided as heating or cooling devices, which allow heat to be supplied to or removed from specific points in a precise manner. Such "heat pipes" are basically known to experts in many technical fields.

[0083] According to some embodiments, the adjusting means may comprise a motor control device of the drive motor, the motor control device being configured to influence the efficiency of the drive motor by varying the energization, thereby imposing a thermal load on the drive shaft, in particular in that it may be provided that the energization to the drive motor is varied by deviating from a sinusoidal curve, thereby increasing losses and therefore heat generation.

[0084] According to some embodiments, it can be provided that the regulating means may comprise one or more temperature sensors, which can be used to control the heating and / or cooling devices within the range of control.

[0085] According to some embodiments, the adjusting means may be configured to control the operation of the drive motor and the motor fan so that the drive motor is operated in a loss mode that generates excessive waste heat and the waste heat to the component by the motor fan is appropriately influenced.

[0086] In this concept, the drive motor is operated in a manner that is somewhat ``energy unfavorable,'' generating waste heat that would not occur during normal, i.e., energy favorable, operation; in this case, by appropriately controlling the operation of the motor fan, the transport of this heat within the pump can be appropriately influenced, and particularly large or small thermal loads can be appropriately applied to the components.

[0087] According to some embodiments, it may be provided that the component has at least one first part and at least one second part, and in this case, the adjusting means is provided so that one or all of the parts have a surface with a thermal emissivity ε of at least 0.25 at 50°C, preferably at least 0.3. Alternatively or additionally, the adjusting means is provided so that the surface of the component is at least partially provided with a coating having a thermal emissivity ε higher than that of the uncoated component. Alternatively or additionally, the adjusting means is provided so that the surface of the component is at least partially treated by oxidation, the component comprising a metallic material containing at least one metallic element, and the treated part of the surface comprises an outer layer containing a compound of the metallic element produced by the oxidation treatment. In this case, it may be provided in particular that the treated part of the surface has a coloration, in which the compound of the metallic element is colored, and / or the outer layer contains a pigment, in which case the coloration is preferably blackened.

[0088] Each of these embodiments achieves improved heat dissipation from the respective component by thermal radiation.

[0089] According to some embodiments, it can be provided that adjustment means are provided, such that the volume defined by the part is at least partially filled with a medium.

[0090] The choice of medium allows the heat transfer between the component and the surroundings to be precisely influenced. The component may be, for example, a corrugated bellows arranged between the moving spiral component and the pump housing. As already mentioned elsewhere, corrugated bellows are basically known as components of scroll vacuum pumps. Alternatively, the component may be rigid and have one or more hollow chambers filled with a medium. Different hollow chambers may be filled with different media. The component may be, for example, a drive shaft.

[0091] The medium may be, for example, a gas or liquid with a relatively high thermal conductivity. The gas is particularly a gas with long chain molecules and / or a relatively high number of thermodynamic degrees of freedom. Tetrafluoromethane may be used as the gas. The liquid may be, for example, water or oil, particularly an oil with a relatively low viscosity.

[0092] According to some embodiments, the adjusting means may comprise a fan device attached to or formed on a part that rotates during operation of the pump, in particular the rotating part being the drive shaft.

[0093] The rotating part thereby forms a fan that can precisely influence the heat transport within the pump.

[0094] According to some embodiments, the adjusting means may include an adjusting device and one or more air guide mechanisms (e.g., flaps) displaceable by the adjusting device. Such air guide mechanisms may be arranged in a hood attached to the pump housing, surrounding a stationary spiral element also attached to the pump housing, and accommodating a fan within the hood. Such mechanisms can influence, for example, the strength and direction of a cold air flow generated by the fan, thereby specifically influencing the temperature balance of the scroll vacuum pump. Such mechanisms can influence heat transport within the pump and / or actively or passively influence the thermal expansion of at least one component during pump operation.

[0095] An eighth aspect of the present invention relates to a method of operating a scroll vacuum pump comprising a pump system having a fixed spiral element and a movable spiral element interacting with the fixed spiral element to provide a pumping action therewith; a drive shaft having an eccentric portion and rotating about an axis of rotation in operation for driving the movable spiral element; and an electric drive motor for the drive shaft, the method comprising adjusting an axial gap dimension between both spiral elements, thereby at least partially directly or indirectly applying a thermal load to the elements and / or influencing heat transport within the pump.

[0096] Also in the context of this aspect of the invention, heat transport is also understood as heat radiation, ie heat absorption or heat dissipation by thermal radiation.

[0097] As mentioned above in connection with the seventh aspect of the invention, the part affected by thermal expansion may be a part that directly or indirectly influences the axial orientation of the movable spiral part, and thus may be, for example, a pump housing, a drive shaft, a rolling bearing, an inner or outer ring of a rolling bearing, a bearing sleeve or an adapter sleeve.

[0098] By thermal loading or by influencing heat transport, the thermal expansion of the components that occurs during pump operation can be actively influenced, thereby directly or indirectly changing the force with which they apply load to the moving spiral components, thereby appropriately adjusting the axial clearance dimensions.

[0099] According to some embodiments, a thermal load can be applied to the drive shaft, and the efficiency of the drive motor can be influenced by varying the current supplied to the drive motor. As mentioned in connection with the seventh aspect of the invention, the variation in the current supplied to the drive motor can be achieved by deviating from a sinusoidal curve, which increases losses and therefore heat generation. Therefore, in this concept, the motor control device of the drive motor can be used to adjust the axial gap dimension. Alternatively or additionally, further eddy current losses can be induced, especially by additional harmonic components.

[0100] For the above-mentioned aspects of the invention, i.e. both the scroll vacuum pump according to the invention and the method according to the invention, it can be provided according to some embodiments that the adjusting means comprises at least one pressure sensor and is configured to adjust the axial gap dimension in dependence on at least one pressure measured by the pressure sensor. This can be done in particular within the range of control. The measured pressure can be, for example, the pressure in the suction region of the scroll vacuum pump.

[0101] According to a ninth aspect of the present invention, in a scroll vacuum pump of the type mentioned at the beginning, adjustment means are provided, which are configured to adjust the axial gap dimension existing between both spiral parts, and wherein the adjustment means are configured to manually adjust the axial gap dimension.

[0102] Manual adjustment of the axial clearance dimension can be made within the range of the initial axial clearance adjustment when the pump is not running. Alternatively or additionally, the adjustment means can be configured to allow manual adjustment of the axial clearance dimension while the pump is running.

[0103] According to some embodiments, the adjustment means may comprise at least one adjustment element actuatable by means of a tool, the adjustment element being arranged between both spiral parts and / or between the fixed spiral part and the pump housing and / or between the movable spiral part and the pump housing.

[0104] The actuatable adjustment element may be, for example, a threaded pin, which is arranged between the spiral housing and the pump housing. A plurality of threaded pins may be provided, which are distributed circumferentially.

[0105] Such threaded pins may be actuated while the pump is running.

[0106] The adjustment means may have a clamping system that can be manually displaced between a relaxed state and a tightened state, in which case, in the relaxed state of the clamping system, the fixed spiral part can be brought into a set or settable target position relative to the movable spiral part by displacing it relative to the clamping system, in which case, by displacing the clamping system into the tightened state, the target position of the fixed spiral part can be fixed.

[0107] A support for the fixed spiral part may be provided additionally or as a component of the clamping system, in which case, in the relaxed state of the clamping system, the fixed spiral part can be brought into the target position by displacing it relative to the support.

[0108] The clamping system can function, for example, based on the principle of a tool holder collet chuck. Accordingly, a plurality of flexible or resiliently displaceable annular segments can be provided, distributed in the circumferential direction. For example, annular clamping elements with conical clamping surfaces can move the annular segments so that the fixed spiral parts are clamped together by the annular segments and are thus fixed in the desired position.

[0109] Together the annular segments may provide support for the stationary spiral component as previously described.

[0110] Such a clamping system also makes it possible to compensate for tilting, i.e. to correct the tilting of the fixed spiral part relative to the pump housing.

[0111] According to some embodiments, the adjustment means may comprise an adjustment screw extending through a passage formed in the drive shaft, the adjustment screw being operable at its rear end portion by a tool and applying a load, directly or indirectly, to the movable spiral element at its front end portion, for example via an elastically deformable element, which may be, for example, a spring-elastic washer.

[0112] In this concept too, it is possible to take advantage of the fact that the support of the movable spiral element, which is effected, for example, via a flange bearing configured as a rolling bearing, allows a certain degree of slight axial movement.

[0113] Advantageously, in this case and in other designs, a certain degree of slight axial mobility of the support of the movable spiral element is utilized when this support has a sufficiently zero backlash. To ensure this zero backlash, it can be provided, in particular, that the support is elastically supported, for example by means of a spring element, on another element, which can be, for example, the drive shaft or the pump housing.

[0114] According to some embodiments, a gas bearing, in particular an axial gas bearing, may be provided, which may in particular be an air bearing. The gas bearing may be arranged, for example, on the rear side of the movable spiral part. The gas bearing may be realized by a narrow gap between the associated parts in combination with a gaseous medium, for example air, under pressure. By varying the gas pressure in the gas bearing, the positioning of at least one of the associated parts, and thus at least indirectly the movable spiral part, can be effected, and thus the axial gap dimension can be adjusted.

[0115] The gas bearing can be configured to be connected to a region of the scroll vacuum pump that is at a pressure level that is desired for the gas bearing. Therefore, various pressure levels are generally available within the scroll vacuum pump and can be used, for example, for the gas bearing. It is possible to design the gas bearing to be precisely associated with the respective pressure range and thus be able to provide a pressure level within this pressure range. Depending on the desired characteristics of the gas bearing, a suitable control device can be used to switch between the various pressure ranges and thus the pressure levels for the gas bearing.

[0116] Such utilization of the various pressure levels present in the scroll vacuum pump may be carried out in further aspects and developments of the invention.

[0117] According to a tenth aspect of the present invention, in a scroll vacuum pump of the type mentioned at the beginning, adjustment means are provided, which are configured to adjust the axial gap between both spiral parts, and wherein the adjustment means are configured to enable one or both spiral parts to achieve self-adjustment, in particular after a running-in period.

[0118] Each spiral part that is self-adjusting forms a component of the adjustment means.

[0119] By means of such an adjusting means, it is possible to achieve an automatic self-adjustment of the respective relative position between the two spiral parts after a running-in period that depends on the respective circumstances.

[0120] According to some embodiments, it may be provided that the spiral wall of the movable spiral part and / or the spiral wall of the fixed spiral part are each provided with a plastically deformable mass at their end faces facing away from the spiral base, which mass may be, for example, a paste or a grease.

[0121] In these embodiments, it is preferably provided that the spiral walls each do not have a tip seal, although in principle it is also possible to combine this concept of a plastically deformable mass with a tip seal.

[0122] This allows the end faces of the spiral walls to be "ground to fit" during the break-in period. During this "ground to fit," the relative movement between each end face and each opposing moving surface, i.e., the spiral base of each other spiral component, causes wear on the end faces, which initially only smooths out any irregularities and tips. As the scroll vacuum pump continues to operate, the wear further increases, at least locally. This allows for a uniform axial clearance dimension around the circumference.

[0123] In connection with this concept, it may be contemplated that the relative position between the movable spiral part and the fixed spiral part is post-adjusted after a predetermined time has elapsed, although such post-adjustment is not required.

[0124] According to some embodiments, it can be provided that the spiral wall of the movable spiral part and / or the spiral wall of the fixed spiral part are each provided with a separate sealing element (tip seal) on the end face facing away from the spiral base, the sealing element being movably arranged, in particular in a groove-like recess, and being preloaded axially towards the respective other spiral part by at least one clamping means.

[0125] According to some embodiments, the sealing element and the recess may have a cross section different from a rectangle. On at least one side, the inner wall of the recess and the side wall of the sealing element facing this inner wall may extend obliquely to the respective spiral wall and thus obliquely to the rotation axis of the drive shaft. The cross-sectional shapes may be, for example, trapezoidal, tapering away from the spiral base of the spiral part with the corresponding spiral wall. However, a trapezoidal shape is not mandatory. Other cross-sectional shapes with an oblique inner wall or side wall on at least one side are also conceivable.

[0126] According to some embodiments, the spiral wall of the movable spiral part and / or the spiral wall of the fixed spiral part may each be provided with a separate sealing element at the end face facing away from the spiral base, the separate sealing element comprising a different material on the side facing the other spiral part than on the side facing away from the other spiral part. The materials may differ, for example, in terms of hardness. In this case, the material facing the other spiral part is preferably softer than the other material. The term "hardness" here refers to the same definition for both materials.

[0127] The present invention will now be described by way of example with reference to the drawings. [Brief explanation of the drawings]

[0128] [Figure 1] An example of such a scroll vacuum pump is shown to explain the basic structure of a conventional scroll vacuum pump. [Figure 2]1 shows an embodiment of a scroll vacuum pump according to the present invention having the basic structure shown in FIG. [Figure 3] 1 shows an embodiment of a scroll vacuum pump according to the present invention having the basic structure shown in FIG. [Figure 4] 1 shows an embodiment of a scroll vacuum pump according to the present invention having the basic structure shown in FIG. [Figure 5] 1 shows an embodiment of a scroll vacuum pump according to the present invention having the basic structure shown in FIG. [Figure 6] 1 shows an embodiment of a scroll vacuum pump according to the present invention having the basic structure shown in FIG. [Figure 7] 1 shows an embodiment of a scroll vacuum pump according to the present invention having the basic structure shown in FIG. [Figure 8] 1 shows an embodiment of a scroll vacuum pump according to the present invention having the basic structure shown in FIG. [Figure 9] 1 shows an embodiment of a scroll vacuum pump according to the present invention having the basic structure shown in FIG. [Figure 10] 1 shows an embodiment of a scroll vacuum pump according to the present invention having the basic structure shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0129] Figure 1 shows a conventional scroll vacuum pump having the basic structure described below. The construction and functioning of such scroll vacuum pumps are known to experts. This conventional scroll vacuum pump can be developed in various ways according to the present invention. Subsequently, various embodiments according to the present invention will be described with reference to Figures 2 to 10.

[0130] The scroll vacuum pump shown in Figure 1 comprises a pump system having a fixed spiral element 11 and a moving spiral element 13 which interact to provide a pumping action during operation. The scroll vacuum pump further comprises a drive shaft 17 which rotates about a rotation axis 15 during operation and has an eccentric portion 19 for driving the moving spiral element 13. Additionally, the scroll vacuum pump is provided with electric drive motors 21, 23 which are used to rotate the drive shaft 17 about the rotation axis 15. The electric drive motor comprises a radially inner motor rotor 21, also referred to as an armature, and a radially outer motor stator 23.

[0131] The drive shaft 17 is rotatably supported in the pump housing 41 at two axially spaced bearing locations 25, 27. The front bearing location 25 is formed by a front rolling bearing configured as a fixed bearing, while the rear bearing location 27 is formed by a rear rolling bearing configured as a free bearing. To support the drive shaft 17, the pump housing 41 is provided with a sleeve-like portion, hereinafter also referred to as a bearing sleeve 115. Thus, both rolling bearings 25, 27 are located radially between the drive shaft 17 and the bearing sleeve 115.

[0132] Both bearing locations 25, 27 are located on the side of the drive motors 21, 23 that is closer to the eccentric portion 19 of the drive shaft 17. Therefore, all bearing locations 25, 27 are located in front of the drive motors 21, 23 within the pump housing 41. In this case, the bearing locations 25, 27 are located in the atmospheric region of the pump, i.e., not in the region where a vacuum acts during pump operation. The eccentric portion 19 is integrally connected to the front end of the drive shaft 17, and the drive motors 21, 23 are seated on the rear end of the drive shaft 17. This structure allows the drive motors 21, 23 to be fitted over the rear end of the drive shaft 17. This facilitates assembly and replacement of the drive motors 21, 23 or parts of the drive motors 21, 23.

[0133] The balancing concept for balancing the rotating system, including inter alia the drive shaft 17 and the moving spiral element 13, includes a front balance weight 29 and a rear balance weight 31 attached to the drive shaft 17. In this case, the front balance weight 29 is arranged in the region of the front end and eccentric part 19 of the drive shaft 17. The rear balance weight 31 is located in front of the rear bearing point 27 and thus in front of the drive motor.

[0134] In variants of this basic design, other balancing concepts are also conceivable: for example, a rear balance weight or an additional balance weight may be arranged in the area of ​​the drive motor at the rear end of the drive shaft.

[0135] Furthermore, a pressure element 87 is provided at the rear end of the drive shaft 17, seated on its end face. The pressure element 87 is rotationally symmetrical and is not used as a balance weight.

[0136] The pressure element 87 is connected to the drive shaft 17 by a central screw 83. To adapt the outer diameter of the rear part of the drive shaft 17 to the inner diameter of the motor rotor 21, a sleeve element 33 is provided on the rear part of the drive shaft 17. The sleeve element 33 is fastened to the motor rotor 21 by the pressure element 87 and the central screw 83. The sleeve element 33 is fixed on the drive shaft 17 by a locating pin 33a. Furthermore, an annular intermediate element 34 is arranged axially between a shoulder 17a formed on the drive shaft 17 and the motor rotor 21. The motor rotor 21 is fastened via the intermediate element 34 between the pressure element 87 and the shoulder 17a of the drive shaft 17, which serves as a support for the intermediate element 34. In the region of the shoulder 17a, a wave spring 99 is arranged between the intermediate element 34 and the free bearing 27 forming the rear bearing part 27.

[0137] The drive motors 21, 23 are arranged completely within the pump housing 41, i.e., they are circumferentially surrounded by the pump housing 41 over their entire axial length and do not protrude rearward. At their rear end, the pump housing 41 is closed by a separate motor lid 103.

[0138] At the front end of the pump housing 41 is located a pump system comprising a fixed spiral element 11 and a moving spiral element 13. The fixed spiral element 11, also called the spiral housing, is screwed to the front end of the pump housing 41 and is surrounded by a hood 105, which is also attached to the pump housing 41 and which further houses a fan 95.

[0139] The movable spiral part 13 is journalled on the eccentric part 19 via a flange bearing 91 configured as a rolling bearing. A washer 93 is located between the axially movable spiral part 13 and the eccentric part 19. An adjusting disk 94 is located between the flange bearing 91 and a circumferential shoulder of the drive shaft 17 at the transition to the eccentric part 19. Accurate circumferential alignment between the fixed spiral part 11 and the pump housing 41 is ensured by a locating pin 97. In variants of this basic design, several locating pins 79 may be provided.

[0140] The fixed spiral element 11 has a spiral unit with a spiral wall 49 and a spiral bottom 51, and a support 53 for the spiral unit, which forms the spiral bottom 51 on the side closer to the movable spiral element 13. For example, two radially outer spiral walls 49 may be provided, which are arranged concentrically and interrupted in the circumferential direction. This results in a parallel pump structure consisting of parallel pumping channels formed by corresponding spiral grooves between the spiral walls 49. The channels merge into pump channels extending spirally radially inward, which are formed by spirally extending spiral grooves and are defined by spirally extending spiral walls 49.

[0141] The movable spiral element 13 likewise has a spiral unit with a spiral wall 69 and a spiral groove 71, and a plate-like support 73 for the spiral unit, which forms the spiral bottom 71 on the side closer to the fixed spiral element 11. Corresponding to the spiral unit of the fixed spiral element 11, two radially outer spiral walls 69 may be provided, which are arranged concentrically and are interrupted in the circumferential direction in the region of the air inlet (not shown). The radially inner spiral wall 69 extends spirally.

[0142] Both the spiral wall 49 of the fixed spiral part 11 and the spiral wall 69 of the movable spiral part 13 are provided with elongated sealing elements 75 (tip seals) at their ends facing away from the respective spiral bottoms 51 or 71.

[0143] The aforementioned spiral units of both spiral parts 11, 13 may also be configured in other ways.

[0144] The gas to be pumped reaches the pump system including both spiral parts 11, 13 via an inlet flange 77 and is discharged via an outlet flange, not shown.

[0145] The pump housing 41 is supported on a base formed by the electronics housing 43. The pump housing 41 is screwed to the electronics housing 43. The electronics housing 43, not shown in full, is provided on its underside with legs, not shown. The electronics housing 43 houses the electronic equipment, including, inter alia, the electronic, electrical and electromechanical components used to power and control the scroll vacuum pump.

[0146] Furthermore, the scroll vacuum pump includes a gas ballast valve, not shown. In a variation of this basic design, instead of a gas ballast valve, a multi-stage gas ballast system may be provided.

[0147] The eccentric drive formed by the drive shaft 17 with the eccentric portion 19 is located inside the pump housing 41 and is surrounded by a deformable sleeve in the form of a corrugated bellows 89. The corrugated bellows 89 serves, on the one hand, to seal the eccentric drive from the suction area of ​​the scroll vacuum pump and, on the other hand, to act as a twist protection for the moving spiral part 13. For this purpose, the corrugated bellows 89 is fixed to the side of the moving spiral part 13 that is closer to the drive. The rear end of the corrugated bellows 89 is attached to the housing base within the pump housing 41 by means of screws.

[0148] As explained at the beginning, an axial gap, generally referred to within the scope of this disclosure as the axial gap size, is provided between the end face of the spiral wall 49 or 69 of one spiral part 11 or 13 and the spiral bottom 71 or 51 of the other spiral part 13 or 11. The axial gap size has an effect on the vacuum capacity of the scroll vacuum pump and thus in particular on the pumping speed of the scroll vacuum pump and the minimum final pressure achievable with the scroll vacuum pump.

[0149] The present invention specifically provides the possibility of adjusting the axial clearance during or outside of pumping operation, depending on the embodiment. One embodiment allows for selectively adjusting the axial clearance during or outside of pumping operation. Various options for adjusting the axial clearance are explained below in conjunction with the drawings, whereby these individual aspects of the invention are illustrated on the example of a conventional scroll vacuum pump having the basic structure as described above with reference to FIG. 1. In this case, in the drawings described below, the aspects of the invention are for the most part only shown diagrammatically in order to explain the respective concepts according to the invention.

[0150] In the embodiment of Fig. 2, the means for adjusting the axial gap size includes an active magnetic bearing 113. The magnetic bearing 113 is arranged on the rear side of the moving spiral part 13 (orbital), i.e., on the side facing away from the fixed spiral part 11 (spiral housing).

[0151] 2 shows a first coil 113a and a second coil 113b of the magnetic bearing, which are arranged axially offset from one another. The axial gap dimension present in each case can be measured by a sensor 113c of the magnetic bearing 113. The sensor 113c may be configured as an eddy current sensor. Alternatively, one or more Hall sensors may be used as the sensor 113c.

[0152] A control device (not shown) of the scroll vacuum pump is configured to control the active magnetic bearing 113, i.e., to adjust the desired axial clearance in each case by varying the bearing force depending on the axial clearance dimension measured by the sensor 113c.

[0153] The scroll vacuum pump may further be provided with one or more pressure sensors. The pressure sensors may be provided, for example, to measure the pressure in the suction region of the scroll vacuum pump. The desired size of the axial gap dimension in each case may depend on the measured suction pressure. Therefore, in the inventive concept of adjusting the axial gap dimension shown in FIG. 2, it may be envisaged that the axial gap dimension varies depending on the measured suction pressure.

[0154] 3 illustrates another option according to the invention for adjusting the axial gap between the spiral housing 11 and the orbital 13. As explained in connection with FIG. 1, a corrugated bellows 89 is arranged between the orbital 13 and the pump housing 41. In this case, the corrugated bellows 89 is fixed at the front to the rear side of the orbital 13 and is supported at the rear by the pump housing 41. The orbital 13 is therefore subjected to an axial force by the corrugated bellows 89 that depends, inter alia, on the pressure acting in the corrugated bellows 89.

[0155] The concept of this embodiment of the invention is to use a corrugated bellows 89, which applies an axial mechanical load to the orbital 13 and thereby adjusts the axial clearance dimension as desired in each case. As already mentioned elsewhere, this is achieved by using the flange bearing 91 which supports the orbital 13 on the eccentric part 19 of the drive shaft 17, which allows for a small axial movement of the orbital 13.

[0156] The pressure p2 in the corrugated bellows 89 can be varied by the valve unit 121, which is shown diagrammatically, together with a control device 123 for the valve unit 121. The interior of the corrugated bellows 89 is connected to the suction region of the scroll vacuum pump via a line 127, the valve unit 121, and another line 125. The line 127 may contain, among other things, a filter device with one or more filter elements and a non-return device with one or more non-return elements. The pressure p1 in the suction region of the scroll vacuum pump varies during operation and can be measured by the pressure sensor 119, which is only diagrammatically indicated. However, such a pressure sensor located in the suction region is not essential. The measurement of the pressure value required for this concept can also be performed via other pressure sensors. The other pressure sensors can be located, for example, in a so-called custom chamber, i.e., in the recipient where the scroll vacuum pump generates vacuum during operation, or at another point in the pump system. Alternatively, the magnitude of the pressure can be inferred via other pump variables, such as the power consumption of the scroll vacuum pump.

[0157] By appropriately operating and controlling the valve unit 121 using a control device 123, which may be provided separately or may be integrated into the scroll vacuum pump's control device (not shown), the pressure in the corrugated bellows 89, which is typically in the range of 1 bar, can be varied, thereby appropriately varying the axial force that the corrugated bellows 89 exerts on the back side of the orbital 13, and thus adjusting the axial gap size.

[0158] The valve unit 21 may be configured as, for example, a solenoid valve, which may be arranged in a hole formed in the corrugated bellows 89, for example.

[0159] 4 illustrates two different options for adjusting the axial clearance. Both options may be provided together in each scroll vacuum pump, but this is not required. That is, each of these two options may be implemented in each scroll vacuum pump alone or in combination with one of the other disclosed inventive aspects.

[0160] As described in connection with Figure 1, a wave spring 99 is disposed between the free bearing 27, which forms the rear bearing point for the drive shaft 17, and the intermediate element 34. In the conventional scroll vacuum pump shown in Figure 1, the wave spring 99 exerts a fixed, unchangeable preload. The magnitude of the preload depends on the characteristics of the wave spring 99.

[0161] One aspect of the invention is to actively influence the preload at the axial location of the wave spring 99. To this end, according to this aspect of the invention, the conventional wave spring 99 is replaced by a modified wave spring 99 or another length-variable device that can be loaded using a device not shown, where the application of the load can be controlled, for example, by the control device of the scroll vacuum pump.

[0162] For example, a wave spring 99 made of bimetal may be provided, which is modified from a conventional wave spring, and in this case the temperature can be precisely varied in areas of this wave spring 99, thereby precisely varying the stiffness of the wave spring 99. For this purpose, the wave spring 99 or areas of the wave spring 99 can be precisely heated or cooled. For this purpose, so-called "heat pipes" (explained in more detail later) can be used, for example.

[0163] Instead of the wave spring 99, a length-variable device 129 may be provided between the free bearing 27 and the intermediate element 34. For example, the length-variable device 129 may be an elastic element, the interior of which can be appropriately loaded with a fluid. In this case, the existence of various zones inside the scroll vacuum pump at different pressure levels, i.e., where different pressures act, may be utilized. For example, it has already been mentioned that a pressure in the range of 1 bar typically acts inside the wave bellows 89. During operation, the suction zone of the scroll vacuum pump is subjected to a very low pressure (vacuum). These examples demonstrate that different pressure zones, i.e., zones where different pressures act, are provided in the scroll vacuum pump in order to apply a load to an elastic element, which is used as the length-variable element 129 and can be loaded, for example, with a gas. This may be utilized by appropriately connecting the elastic element 129 to the respective pressure zone and thereby bringing it to the pressure level of this pressure zone. Depending on the respective desired preload to be generated by the elastic element 129, a changeover between different pressure ranges and thus pressure levels can be effected by means of a suitable control device.

[0164] Another embodiment according to the invention, specifically shown in Figure 4, is that the adjusting means comprises at least one actuator, for example a piezo-actuator, for adjusting the axial gap. The actuator is used to apply an axial mechanical load directly or indirectly to the spiral housing 11 or the orbital 13.

[0165] Figure 4 specifically shows an example in which an actuator 117 is arranged between the spiral housing 11 and the pump housing 41. Only one piezo actuator 117 is shown schematically in Figure 4. In one possible embodiment, a plurality of actuators 117 are preferably arranged symmetrically around the rotation axis 15 and distributed circumferentially. For example, three piezo actuators 117 may be provided, each spaced apart by an angle of 120°.

[0166] By means of a control device (not shown) of the scroll vacuum pump, these piezo actuators can be activated collectively or independently of one another, and can also be activated so as to vary the axial distance between the pump housing 41 and the spiral housing 11, thereby adjusting the axial gap between the spiral housing 11 and the orbital 13. Correction of the tilted position of the spiral housing 11 relative to the housing 41 is also possible, for example, by appropriately differently activating the circumferentially distributed actuators 117.

[0167] The location of such an actuator between the spiral housing 11 and the pump housing 41 is shown in FIG. 4 as one possible example of the positioning of such an actuator 117. The actuator 117 may also be located elsewhere between two components of the scroll vacuum pump, specifically at a location where it is possible to apply a direct or indirect mechanical load axially to one of the two spiral components 11, 13. For example, one or more actuators 117 may be located between the two spiral components 11, 13 or between the movable spiral component 13 and the pump housing 41. Since the drive shaft 17 is coupled at its front end to the orbital component 13, it is also possible to apply a mechanical load to the drive shaft 17, thereby changing the axial orientation of the orbital component 13 relative to the spiral housing 11. Thus, for example, one or more actuators 117 may be located between the drive shaft 17 and a receiving portion, such as provided by the pump housing 41, or between a component coupled to the drive shaft 17.

[0168] 4, when one or more actuators 117 are arranged between the spiral housing 11 and the pump housing 41, an initial axial clearance adjustment can be performed by first adjusting the axial gap dimension to the desired value using one or more actuators 117 and then fixing the adjusted state by screwing the spiral housing 11 to the pump housing 41. Even when the spiral housing 11 and the pump housing 41 are not rigidly screwed together but are connected to each other in a different way, such that the adjusted axial gap dimension is sufficiently fixed but can nevertheless be changed by the actuators 117, axial clearance adjustment during pump operation using one or more such actuators 117 is possible. This can be achieved, for example, by a sufficiently rigid support of the spiral housing 11 on the pump housing 41, so that the adjusted axial gap dimension cannot itself be changed during operation, but this rigidity can be overcome by the actuators 117 to change the axial gap dimension. For this purpose, for example, the spiral housing 11 may be supported on a pin so that it can slide axially and be preloaded axially towards the pump housing 41 by a spring, with a suitable sealing device providing the required sealing between the spiral housing 11 and the pump housing 41 in each case.

[0169] 5, 6 and 7 illustrate various options for realizing further embodiments according to the invention, in which the axial gap dimension between two spiral parts 11, 13 is adjusted, in order to at least partially apply a direct or indirect thermal load to at least one part or another, thereby actively or passively influencing the thermal expansion of at least one part occurring during pump operation or influencing the heat transport within the pump.

[0170] The means, hereinafter also referred to as thermal means or thermal concepts, may be combined with one another. In some embodiments, this proves to be essential. For example, a thermal load may be applied to a component by influencing the heat transport in the pump, which also means an active influence on the thermal expansion of this component.

[0171] However, the combination of the described measures is not required. Thus, for example, the thermal expansion of a component can be passively influenced without affecting the heat transport within the pump and without actively applying a thermal load to the component. The component can be made of materials with different thermal expansion coefficients, for example. During pump operation, a temperature rise occurs within the pump, causing different parts of the component to expand to different degrees. When the temperature rise occurring during pump operation is also known and therefore predictable, the effect of the thermal properties of the component on, for example, a moving spiral component can be predicted, since the thermal properties of the material and thus the component in question are known and therefore predictable.

[0172] Therefore, the selection of materials with different thermal expansion coefficients provides a passive means for adjusting the axial gap dimension. As mentioned elsewhere, the term "adjust" also includes "maintaining" the axial gap dimension at a predetermined target value. By virtue of the material selection and predictable thermal expansion characteristics of the relevant components, the axial gap may be maintained at least substantially at the respective desired target value, despite the heating of the interior of the scroll vacuum pump during pump operation. Materials with negative thermal expansion coefficients may also be used, which opens up additional possibilities for actively or passively influencing the thermal expansion of the relevant components.

[0173] The disclosed thermal concept of adjusting the axial gap size does not require different thermal expansion coefficients for the individual components. Thermal measures can include targeted heating or cooling of one or more components, thereby influencing their thermal expansion and thus the axial gap size. As already mentioned elsewhere, thermal measures can utilize the existing fan of a scroll vacuum pump, for example. Alternatively or additionally, it is conceivable to provide the vacuum pump with one or more so-called "heat pipes" (also called heat tubes). Such heat pipes, which are generally known to experts in themselves, allow heat to be supplied to or removed from specific locations in a targeted manner.

[0174] FIG. 5 illustrates two different means for passively influencing the thermal expansion of several parts of a scroll vacuum pump, namely the drive shaft 17 on the one hand and the bearing sleeve 115 on the other hand (which in the basic design described with reference to FIG. 1 forms an integral component of the pump housing 41).

[0175] According to one approach, portion 17b of drive shaft 17 may be made of a material with a negative coefficient of thermal expansion. As the temperature inside the scroll vacuum pump increases, the axial length of this portion 17b decreases, while the rest of drive shaft 17 expands axially. Overall, based on the predictability of thermal effects, it is possible to achieve that the axial length of drive shaft 17 remains at least essentially constant, regardless of the temperature actually occurring inside the scroll vacuum pump. Thus, the axial position of orbital 13, coupled to the front end of drive shaft 17, remains unchanged during pump operation. Alternatively, by selecting the material of portion 17b and its axial length, the thermal expansion characteristics of drive shaft 17 can be tailored so that, for a particular temperature, e.g., the rated operating temperature inside the scroll vacuum pump, a particular axial orientation of orbital 13 occurs that differs from the axial orientation of orbital 13 at temperatures inside the scroll vacuum pump below the rated operating temperature. By additional measures, namely the thermal loading of one or more portions of the drive shaft 17, for example by appropriate heating of the portion 17b of the drive shaft 17 or by appropriate cooling of one or more other portions of the drive shaft 17, the axial clearance dimension can be adjusted precisely during pump operation.

[0176] Alternatively or additionally to providing the described portion 17b of the drive shaft 17, the bearing sleeve 115 can be made of a material whose thermal expansion coefficient differs from that of the material of the rest of the pump housing 41. In this case, the bearing sleeve 115 is no longer an integral part of the pump housing 41, but is instead connected to the pump housing 41 in such a way that good heat transfer is achieved by thermal conduction between the bearing sleeve 115 and the pump housing. A thermally induced change in the axial length of the bearing sleeve 115 changes the axial position of the drive shaft 17 relative to the pump housing 41 and thus the attitude of the orbital 13 relative to the pump housing 41 and therefore also relative to the fixed spiral part 11. Therefore, in this way, the axial clearance dimension can also be adjusted here.

[0177] FIG. 6 illustrates two thermal measures which may be provided either alone or in combination.

[0178] One method is to utilize the rotation of the drive shaft 17. In this case, rotor blades 131 are attached to the outside of the drive shaft 17 in the axial region between the flange bearing 91 and the front bearing point formed by the fixed-side bearing 25. A plurality of rotor blades 131 may be provided, spaced apart from one another in the circumferential direction. A fan device is thereby realized in this axial region by the rotating drive shaft 17 and one or more rotor blades 131. The fan device can influence the heat transport within the scroll vacuum pump. This fan action can, in particular, cool the orbital 13.

[0179] At the mentioned axial locations, the full circumference of the drive shaft is not provided because the forward balance weight 29 requires space. Nevertheless, the fan action of the drive shaft 17 can be obtained by one or more rotor blades 31. When designing the forward balance weight 29 and attaching it to the drive shaft 17, the additional mass of the rotor blade(s) 131 can be taken into account so that balance is maintained despite the rotor blade(s) 131.

[0180] In this case, heat dissipation can be further improved by providing a heat dissipation structure, such as ribs or fins, on the back side of the support 73 of the orbital 13 so that heat can be dissipated to the gaseous medium within the corrugated bellows 89.

[0181] 6 consists in generating an air flow through the scroll vacuum pump. For this purpose, an air supply line passes from the outside of the pump housing 41 through the pump housing 41 to an interior region of the scroll vacuum pump located within the corrugated bellows 89, and from there to the outside via an exhaust line 135 which also passes through the pump housing 41. For this purpose, as shown diagrammatically in the example of the exhaust line 135, a recess 133 may be provided in the bearing sleeve 115 of the pump housing 41, from which the exhaust line 135 starts.

[0182] The air flow through the scroll vacuum pump can be controlled using a valve unit 139 that is assigned a control device 141. The control device 141 may be provided separately to the valve unit 139 or may be integrated into the control device, not shown, of the scroll vacuum pump.

[0183] This controllable air flow through the interior of the scroll vacuum pump allows for targeted cooling of the interior of the scroll vacuum pump and in that way influences the heat transport within the scroll vacuum pump. Additionally, this cooling air flow can be used to provide cooling in the area of ​​the drive motors 21, 23.

[0184] In fact, it is found that during pump operation, the temperature of the orbital 13 is typically about 20 to 30 K higher than the temperature of the fixed spiral housing 11. Therefore, heat dissipation from the orbital 13 affects the thermal expansion of the orbital 13, and thus provides a particularly effective means for adjusting the axial gap size between the orbital 13 and the fixed spiral housing 11.

[0185] According to the embodiment specifically shown in Figure 7, heat dissipation from the orbital 13 can be achieved by active control of the scroll vacuum pump fan 95. The speed of the fan 95, and therefore its cooling effect, can be varied, for example, by a controller (not shown) of the scroll vacuum pump. The fan 95 may have its own controller that can communicate with the scroll vacuum pump controller.

[0186] The arrows W in Figure 7 illustrate how heat is transferred from the orbital 13 through the flange bearing 91, the front fixed bearing 25, the rear free bearing 27, and the drive shaft 17 itself to the pump housing 41. Through the pump housing 41, the heat can then be pumped out to the surroundings.

[0187] The embodiments described above in connection with Figures 2 to 7 are used to adjust the axial clearance dimension during pump operation. As explained at the beginning, the present invention also includes adjustment means configured to adjust the axial clearance dimension outside of pump operation. For example, an initial axial clearance adjustment may be performed during assembly of the scroll vacuum pump. Alternatively or additionally, the axial clearance dimension may be adjusted during maintenance or when preparing the scroll vacuum pump for new use. The adjustment may be performed, in particular, manually or with the aid of a tool.

[0188] An example of the manual adjustment of the axial clearance dimension is shown in Figure 8. Instead of the central screw 83 provided at the rear end of the drive shaft 17 in the conventional basic design (see Figure 1), an adjustment screw 143 is provided here, guided through a through-hole formed in the drive shaft 17. The front free end region of the body 143a of the adjustment screw 143 is externally threaded, which interacts with an internal thread in a hole formed in a washer 93, as in a type of spindle drive, with the front free end region of the body 143a forming a threaded spindle and the washer forming a spindle nut. Since the washer 93 is arranged between the front end of the drive shaft 17 and the rear face of the orbital 13 so that it cannot rotate relative to the front end of the drive shaft 17, the axial position of the washer 93 and therefore the axial position of the orbital 13 can be changed and therefore adjusted by rotating the adjustment screw 143. With the motor cover 103 removed, the head of the adjustment screw 143 is accessible from the outside and can be operated using conventional tools, such as a screwdriver or an Allen wrench (Inbus).

[0189] The zero backlash of the flange bearing 91, which is necessary for this adjustment capability, is ensured by a spring unit 145 arranged between the drive shaft 17 and the inner ring of the flange bearing 91. The spring unit 145 may be formed, for example, from a wave spring.

[0190] 9 shows a further embodiment of the concept in which the means for adjusting the axial gap dimension are configured for manual adjustment of the axial gap dimension. The scroll vacuum pump is only shown very diagrammatically here and may again have the basic structure as described with reference to FIG.

[0191] In the embodiment shown in Fig. 9, the adjustment means comprise a clamping system 151 for the spiral housing 11, which is shown only diagrammatically. This clamping system 151 functions in principle according to the principle of a collet chuck, which is known to those skilled in the art. The support for the spiral housing 11, which here forms a component of the clamping system 151, comprises a plurality of circumferentially distributed annular segments 153 arranged on the pump housing 41, which is also shown diagrammatically here, and which act as clamping jaws. The annular segments 153 may be separate elements suitably connected to the pump housing 41. Furthermore, the annular segments 153 may also be formed integrally with the pump housing 41.

[0192] The annular segment 153 is elastically displaceable, in particular by means of an annular clamping element 155 belonging to the clamping system 151. In the example shown, this clamping ring 155 has on its inside a conical surface, via which it interacts with a corresponding opposing surface of the annular segment 153. The clamping ring 155 can be screwed axially onto the pump housing 41.

[0193] In the relaxed state, as specifically shown in FIG. 9, the spiral housing 11 can be displaced relative to the annular segment 153, thereby bringing it into the respective desired target position relative to an orbital (not shown in FIG. 9), i.e., relative to the moving spiral part of the pump system of the scroll vacuum pump. On its outer periphery, the spiral housing 11 is provided with a convex outer contour 157, e.g., a ball-shaped annular section or individual dome-shaped projections, via which the spiral housing 11 can be held securely against the annular segment 153 in the relaxed state with only slight tightening, but can be displaced relative to the annular segment 153. Once the spiral housing 11 is in the respective target position, a clamping ring 155 is threaded onto the pump housing 41 and is thereby inserted onto the annular segment 153. The annular segment 153 is thereby deformed radially inward, thereby clamping the spiral housing 11. In this clamped state of the clamping system 151, the relative position between the spiral housing 11 and the pump housing 41, and therefore the relative position between the two spiral parts, is fixed.

[0194] 10 shows a schematic illustration of an embodiment of the concept according to the invention, in which the means for adjusting the axial gap dimension are configured to allow self-adjustment of at least one of the spiral parts. The scroll vacuum pump in question may again have the basic structure as described with reference to FIG.

[0195] 10 shows an example of an orbital spiral wall 69 with a sealing element 75 (tip seal) arranged on an end face 165 of the spiral wall 69. The seal 75 faces with its surface 160 the spiral bottom 51 of the spiral housing support 53. Between this surface 160 and the spiral bottom 51 there is an axial gap.

[0196] The geometry of the seal 75 and the recess 171 in the end face 165 of the spiral wall 69, which accommodates the seal 75, is known per se from EP 4174285. Regarding the geometry shown in Fig. 10 in a cross section perpendicular to the longitudinal extension of the spiral wall 69 and the seal 75 and thus perpendicular to the axis of rotation of the drive shaft (see Fig. 1), as well as possible deviations from the illustrated geometry, and the advantages of this design, reference is made to the aforementioned EP 4174285. As explained there, the advantage of this design is that during operation of the scroll vacuum pump, a pressure difference between adjacent pumping chambers (see the introduction regarding the functioning of the pumping system of the scroll vacuum pump) generates a force that essentially presses the movable seal 75 in the recess 171, upward in Fig. 10, against the spiral base 51 of the support 53. Depending on the pressure difference, the respective oblique inner wall 173 of the recess 171 interacts with the respective oblique side wall 161 of the seal 75 to the right or left in FIG. 10 . On the one hand, this geometry ensures that as friction increases on the surface 160 of the seal 75 due to wear of the seal 75, the seal 75 can further exit the recess 171, thereby providing a certain degree of automatic wear compensation. On the other hand, the seal 75 is secured in the recess 171 due to this geometry.

[0197] 10 further includes a resilient biasing means 167 having a plurality of springs 168 between the bottom 175 of the recess 171 and the underside 162 of the seal 75. The biasing means 167 allows for a quick grinding fit process of the seal 75.

[0198] In the illustrated embodiment, both the seal 75 and the recess 171 are trapezoidal in cross section, in which case the trapezoid of the seal 75 is smaller than the trapezoid of the recess 171, i.e., the width of the opening 163 of the recess 171 is greater than the width of the seal 75 in the upper region including the upper surface 160.

[0199] The grinding fit of the seal 75 is synonymous with self-adjustment of the corresponding spiral component, here orbital 13 including the illustrated spiral wall 69, thereby adjusting the axial clearance dimension.

[0200] This measure, alone or in combination with other measures disclosed herein, makes it possible to eliminate the relative tilting position between both spiral parts.

[0201] The configuration shown in FIG. 10 may be provided in addition to other embodiments or combinations of embodiments, particularly those disclosed herein. [Explanation of symbols]

[0202] 11 Fixed spiral parts, spiral housing 13 Moving spiral parts, orbital 15 Rotation axis 17 Drive shaft 17a Shoulder 17b part 19 Eccentric part 21 Motor rotor 23 Motor stator 25 Front bearing location (fixed side bearing) 27 Rear bearing location (free side bearing) 29 Front balance weight 31 Rear balance weight 33 Sleeve Elements 33a Locating pin 34 Intermediate Elements 41 Pump housing 43 Electronics Housing 49 Spiral wall of fixed spiral part 51 Spiral bottom 53 Support 69 Spiral wall of moving spiral part 71 Spiral bottom 73 Support 75 sealing elements 77 Air intake flange 83 Central screw 87 Pressure element 89 Corrugated Bellows 91 Flange bearing 93 Washer 94 Adjustment disc 95 fans 97 Locating pin 99 Wave Spring 103 Motor cover 105 Food 113 Active Magnetic Bearings 113a First coil 113b Second coil 113c Eddy current sensor 115 Bearing sleeve 117 Actuator 119 Pressure Sensor 121 Valve unit 123 Control Device 125 lines 127 lines 129 Variable length device 131 Rotor blades, fan devices 133 Recess 135 Exhaust line 137 Air supply line 139 Valve Unit 141 Control device 143 Adjustment screw 143a shaft 145 Spring unit 151 Fastening System 153 Annular Segments 155 Annular fastening element 157 Outer contour 160 Top 161 Side wall 162 Bottom surface 163 Opening 165 End face 167 Actuation means 168 Spring 171 recess 173 Inner wall 175 bottom W heat

Claims

1. In scroll vacuum pumps, a pump system (11, 13) having a fixed spiral element (11) and a movable spiral element (13) that interacts with the fixed spiral element (11) to provide a pumping action; a drive shaft (17) having an eccentric portion (19) for driving the moving spiral element (13), the drive shaft rotating in operation about a rotation axis (15); an electric drive motor (21, 23) for the drive shaft (17); A scroll vacuum pump, wherein an axial gap dimension exists between both spiral parts (11, 13), and an adjusting means is provided configured to adjust the axial gap dimension.

2. the adjusting means are configured to apply a load, in particular a mechanical load, to one of the spiral parts (11, 13), in particular to the movable spiral part (13), or to both spiral parts (11, 13); and / or the adjusting means are configured to influence the relative axial position between both spiral parts (11, 13) with respect to the axis of rotation (15); 2. The scroll vacuum pump of claim 1.

3. a measuring device (113c) is provided, the measuring device (113c) being configured to measure the axial clearance dimension at one or more points, in particular continuously during pump operation; and / or 3. The scroll vacuum pump according to claim 1, wherein the spiral wall (69) of the movable spiral part (13) and the spiral wall (49) of the fixed spiral part (11) do not have separate sealing elements on their end faces facing away from the spiral bottom (71, 51).

4. A method of operating a scroll vacuum pump, the scroll vacuum pump comprising: a pump system (11, 13) having a fixed spiral element (11) and a movable spiral element (13) that interacts with the fixed spiral element (11) to provide a pumping action; a drive shaft (17) having an eccentric portion (19) for driving the moving spiral element (13), the drive shaft rotating in operation about a rotation axis (15); an electric drive motor (21, 23) for the drive shaft (17); In the method, The method for operating a scroll vacuum pump comprises adjusting the axial gap dimension present between both spiral parts (11, 13).

5. In scroll vacuum pumps, a pump system (11, 13) having a fixed spiral element (11) and a movable spiral element (13) that interacts with the fixed spiral element (11) to provide a pumping action; a drive shaft (17) having an eccentric portion (19) for driving the moving spiral element (13), the drive shaft rotating in operation about a rotation axis (15); an electric drive motor (21, 23) for the drive shaft (17); and adjusting means adapted to adjust the axial gap dimension present between both spiral parts (11, 13), A scroll vacuum pump, wherein the adjusting means comprises at least one active magnetic bearing (113) for the moving spiral part (13).

6. In scroll vacuum pumps, a pump system (11, 13) having a fixed spiral element (11) and a movable spiral element (13) that interacts with the fixed spiral element (11) to provide a pumping action; a drive shaft (17) having an eccentric portion (19) for driving the moving spiral element (13), the drive shaft rotating in operation about a rotation axis (15); an electric drive motor (21, 23) for the drive shaft (17); and adjusting means adapted to adjust the axial gap dimension present between both spiral parts (11, 13), A scroll vacuum pump comprising a corrugated bellows (89) disposed between a movable spiral element (13) and a pump housing (41), and the adjusting means is configured to vary the pressure in the corrugated bellows (89).

7. In scroll vacuum pumps, a pump system (11, 13) having a fixed spiral element (11) and a movable spiral element (13) that interacts with the fixed spiral element (11) to provide a pumping action; a drive shaft (17) having an eccentric portion (19) for driving the moving spiral element (13), the drive shaft rotating in operation about a rotation axis (15); an electric drive motor (21, 23) for the drive shaft (17); and adjusting means adapted to adjust the axial gap dimension present between both spiral parts (11, 13), The adjusting means is configured to vary the preload of the drive shaft (17), the rotary bearings (25, 27) of the drive shaft (17), or the bearing sleeve (115) of the drive shaft (17).

8. In scroll vacuum pumps, a pump system (11, 13) having a fixed spiral element (11) and a movable spiral element (13) that interacts with the fixed spiral element (11) to provide a pumping action; a drive shaft (17) having an eccentric portion (19) for driving the moving spiral element (13), the drive shaft rotating in operation about a rotation axis (15); an electric drive motor (21, 23) for the drive shaft (17); and adjusting means adapted to adjust the axial gap dimension present between both spiral parts (11, 13), the adjusting means comprises at least one actuator (117), preferably a piezo-actuator, configured to apply a mechanical load to the fixed spiral part (11) or the moving spiral part (13), directly or indirectly, in an axial direction relative to the axis of rotation (15); In particular, the actuator (117) is arranged between the fixed spiral part (11) and the pump housing (41), between both spiral parts (11, 13), between the moving spiral part (13) and the pump housing (41), or between the rolling bearing and the drive shaft (17) or a part connected to the drive shaft (17).

9. In scroll vacuum pumps, a pump system (11, 13) having a fixed spiral element (11) and a movable spiral element (13) that interacts with the fixed spiral element (11) to provide a pumping action; a drive shaft (17) having an eccentric portion (19) for driving the moving spiral element (13), the drive shaft rotating in operation about a rotation axis (15); an electric drive motor (21, 23) for the drive shaft (17); and adjustment means adapted to adjust the axial gap dimension existing between both spiral parts (11, 13), in particular to compensate for the tilted attitude of the fixed spiral part (11) relative to the pump housing (41), The adjusting means comprises a plurality of actuators (117), in particular piezo actuators, distributed in particular uniformly around the axis of rotation (15), each configured to apply a mechanical load, directly or indirectly, to the fixed spiral part (11) or the moving spiral part (13) in the axial direction relative to the axis of rotation (15), and the actuators (117) are controllable by a control device to operate together or independently of each other so that the axial gap dimension between the fixed spiral part (11) and the moving spiral part (13) is adjusted.

10. In scroll vacuum pumps, a pump system (11, 13) having a fixed spiral element (11) and a movable spiral element (13) that interacts with the fixed spiral element (11) to provide a pumping action; a drive shaft (17) having an eccentric portion (19) for driving the moving spiral element (13), the drive shaft rotating in operation about a rotation axis (15); an electric drive motor (21, 23) for the drive shaft (17); and adjusting means adapted to adjust the axial gap dimension present between both spiral parts (11, 13), the adjusting means are configured to actively or passively influence the thermal expansion of at least one component (17, 115) that occurs during pump operation; and / or A scroll vacuum pump, wherein the regulating means is configured to affect heat transport within the pump.

11. A method of operating a scroll vacuum pump, the scroll vacuum pump comprising: a pump system (11, 13) having a fixed spiral element (11) and a movable spiral element (13) that interacts with the fixed spiral element (11) to provide a pumping action; a drive shaft (17) having an eccentric portion (19) for driving the moving spiral element (13), the drive shaft rotating in operation about a rotation axis (15); an electric drive motor (21, 23) for the drive shaft (17); In the method, The method for operating a scroll vacuum pump comprises adjusting the axial gap dimension present between both spiral components (11, 13) by at least partially directly or indirectly applying a thermal load to the components (17, 115) and / or by influencing the heat transport within the pump.

12. 10. A scroll vacuum pump or method according to any one of the preceding claims, wherein the adjusting means comprises at least one pressure sensor (119), the adjusting means being configured to adjust, in particular within a control range, the axial gap dimension in dependence on at least one pressure measured by the pressure sensor (119).

13. In scroll vacuum pumps, a pump system (11, 13) having a fixed spiral element (11) and a movable spiral element (13) that interacts with the fixed spiral element (11) to provide a pumping action; a drive shaft (17) having an eccentric portion (19) for driving the moving spiral element (13), the drive shaft rotating in operation about a rotation axis (15); an electric drive motor (21, 23) for the drive shaft (17); and adjusting means adapted to adjust the axial gap dimension present between both spiral parts (11, 13), A scroll vacuum pump, wherein the adjustment means is configured to manually adjust the axial clearance dimension, particularly within the range of the initial axial clearance adjustment outside of pump operation, and / or during pump operation.

14. In scroll vacuum pumps, a pump system (11, 13) having a fixed spiral element (11) and a movable spiral element (13) that interacts with the fixed spiral element (11) to provide a pumping action; a drive shaft (17) having an eccentric portion (19) for driving the moving spiral element (13), the drive shaft rotating in operation about a rotation axis (15); an electric drive motor (21, 23) for the drive shaft (17); and adjustment means adapted to adjust the axial gap dimension existing between both spiral parts (11, 13), in particular to compensate for the tilted attitude of the fixed spiral part (11) relative to the pump housing (41), The adjusting means has a clamping system (151) that can be manually displaced between a relaxed state and a tightened state, and in the relaxed state of the clamping system (151), the fixed spiral part (11) can be brought to a set or settable target position relative to the movable spiral part (13) by displacing it relative to the clamping system (151), and the target position of the fixed spiral part (11) can be fixed by displacing the clamping system (151) to the tightened state.

15. In scroll vacuum pumps, a pump system (11, 13) having a fixed spiral element (11) and a movable spiral element (13) that interacts with the fixed spiral element (11) to provide a pumping action; a drive shaft (17) having an eccentric portion (19) for driving the moving spiral element (13), the drive shaft rotating in operation about a rotation axis (15); an electric drive motor (21, 23) for the drive shaft (17); and adjusting means adapted to adjust the axial gap dimension present between both spiral parts (11, 13), A scroll vacuum pump, wherein the adjustment means is configured so that one or both of the scroll parts (11, 13) are self-adjusting, particularly after a break-in period.

Images