Patent Description:
In particular, the invention relates to a compressor device with a bearing damper that can be used with a bearing, which is used to install an axis of a drive of, for instance, a compressor element in the drive housing.

Compressor elements are known to be driven at high rotational speeds by the drive.

This makes the device sensitive to vibration-related problems that occur at such large rotational speeds, as shaft resonances will be in the operating range. Vibrations or oscillations generated in the compressor element and/or the drive may propagate through the transmission. The excitations or resonances that cause these vibrations are mainly due to drive imbalance and due to pulsations caused by the operating forces of the compressor element.

Various dynamic problems will occur, both in the drive and in the compressor element.

One of these problems is related to axial excitation or resonance of the drive shaft and/or the compressor element, wherein the shaft will vibrate in the axial direction.

Such axial displacements of the shafts will occur mainly in the motor, but may also cause problems in the compressor element, as very strict tolerances apply in the compressor element which allow little or no axial movement of the shaft.

In <CIT> a bearing damper element, bearing and compressor element provided with such a bearing damper element and method for manufacturing such a bearing damper element is disclosed. In <CIT> a fluid dampened support having variable stiffness and damping is disclosed. So far, this problem has not been solved in a really satisfactory way.

Typically, heavier bearings will be used to achieve sufficient stiffness and/or bearings will be replaced at regular intervals.

However, use of a flexible coupling between the drive and the compressor element, which provides dynamic decoupling between the drive dynamics and the compressor element as well as damping of excitations or resonances, does have some disadvantages:.

For that reason, usually still a so-called direct coupling is preferred, wherein the flexible coupling is omitted, so eventually still the use of heavier bearings and/or regular replacement of bearings is opted for.

The current invention aims at providing at least a solution to said axial vibrations and other problems.

The current invention relates to a compressor device according to claim <NUM>. Further embodiments are defined in the appended dependent claims.

It should be noted here that said shaft, of which all bearings that carry a static axial load are provided with a bearing damper, may be a drive shaft or a compressor element shaft.

An advantage is that such a bearing damper will be able to dampen axial vibrations, which may, for instance, occur in a drive bearing.

A bearing damper according to the invention will be suitable to secure the bearing in the radial direction, but will allow some flexibility or displacement of the bearing in the axial direction.

The phrase "wherein the coupling element leaves little or no room for movement of the bearing relative to the housing in the radial direction compared to the axial direction" means that the radial bearing displacement relative to the housing is at least a factor <NUM> smaller than the axial bearing displacement relative to the housing, and preferably a factor <NUM> smaller and more preferably a factor <NUM> smaller.

When the bearing damper is installed in the drive housing and around a drive bearing, axial vibrations or bearing vibrations will cause the bearing and housing to move relative to each other in an axial direction, causing the bearing damper and in particular the coupling element to deform.

This will allow the flexible material to absorb deformations, thus dampening the resonances.

Consequently, this will prevent these axial resonances from reducing the service life of the bearing system, or from causing unacceptable dynamic axial displacements of the shaft at which the damping is provided, or from propagation of the vibrations through the machine.

Said coupling element is a ring-shaped element comprising at least one ring.

By choosing a suitable material and thickness of the ring, the necessary stiffness in the radial direction and the necessary flexibility in the axial direction can be obtained.

Preferably, the axial stiffness of the bearing damper should be chosen lower than the axial component of the stiffness of the bearing concerned:
K_Ide,ax ≤ K_I,ax
where K_Ide,ax is the axial spring constant of the bearing damper and K_I,ax is the axial spring constant of the bearing.

The radial stiffness of the bearing damper is preferably of the same magnitude or greater than the radial component of the bearing stiffness:
A * K_I,rad ≤ K_Ide,rad ≤ B * K_I,rad,.

In a practical embodiment, the rings are held together along their inner edges and/or outer edges by an inner clamping strip and/or an outer clamping strip respectively.

This has the advantage that, by broadening the clamping strips, more than two rings can be used in the bearing damper.

Such a modular system will allow the use of as many rings as necessary, depending on the desired or necessary damping and axial stiffness.

Spacers are preferably provided between the inner edges and the outer edges of two consecutive rings.

This will ensure the correct spacing between the successive rings when placed in the clamping strips.

Alternatively, it is of course also possible to provide grooves in the clamping strips in which, as it were, the rings snap into place.

It is clear that alternative embodiments are also possible instead of the use of clamping strips. For example, the inner clamping strip and the outer clamping strip together with said rings could form one assembly or be made of one piece.

In other words, the clamping strips and the rings are not separate parts in that case.

The invention also concerns a bearing of which the bearing damper and the inner or outer bearing ring form one single unit.

In a practical embodiment, the bearing and the housing or the inner clamping strip and the outer clamping strip are provided with clamping surfaces between which the damping element is located, which clamping surfaces extend in the axial or radial direction.

By providing the damping elements between such clamping surfaces, they will be subjected to compression load, for radial-oriented clamping surfaces, or under axial shear stress, for axial-oriented clamping surfaces, due to the axial deformation of the coupling element, which will dampen the axial excitations.

According to the claimed invention, the ring-shaped element is composed of at least two adjacent rings, with damping elements installed between the rings.

The rings may be fitted with spokes extending between an inner edge and an outer edge of the respective rings, wherein the spokes of the first ring are aligned with the spokes of the second ring, with damping elements attached between the aligned spokes.

The spokes may extend in a radial sense or in a non-radial sense. The spokes may also extend skewed, i.e. at an angle with the radial sense, or these may be not straight, but curved or spiral-shaped spokes.

In that case, the damping elements will be subjected to radial shear stress when the rings deform or bend under the axial excitations.

The disclosure also concerns a device with a housing and a rotating shaft with a bearing installed in it, characterized in that the bearing is fitted with a bearing damper which comprises a coupling element and at least one damping element made from a damping elastomer material, wherein the bearing damper is fitted between the bearing and the device housing, using the coupling element, wherein the coupling element allows little or no movement of the bearing relative to the housing in the radial direction and wherein the damping element is configured to dampen the axial movement of the bearing relative to the housing.

To better demonstrate the characteristics of the invention, the following describes, as an example without any restrictive character, some preferred versions of a compressor device according to the invention, with reference to the accompanying drawings, wherein:.

Compressor element <NUM> schematically shown in <FIG> comprises a housing <NUM> containing in this case one compressor element <NUM> and a drive <NUM> for compressor element <NUM>.

Housing <NUM> comprises a section 2a for the drive <NUM> and a section 2b for compressor element <NUM>.

Compressor element <NUM> comprises two rotors <NUM> installed in the housing <NUM> by means of bearings <NUM>.

In this case, drive <NUM> is an electric motor with a motor stator <NUM> and a motor rotor <NUM>, the latter rotatably installed using bearings <NUM> in the housing <NUM>.

In this case, there is one bearing <NUM> that carries a static axial load.

Of course, it is not excluded that there are several bearings <NUM> that carry static axial loads.

Said bearing <NUM> is fitted with a bearing damper <NUM>, which is shown in more detail in <FIG>.

The bearing damper element <NUM>, schematically shown in <FIG>, mainly comprises a coupling element <NUM> and at least one damping element <NUM> made from a damping elastomer material.

In this case, the coupling element <NUM> is a ring-shaped element <NUM> which includes at least one ring <NUM>.

This coupling element <NUM> is intended to install the bearing damper <NUM> between a bearing <NUM> of compressor device <NUM> and the housing <NUM> of compressor device <NUM>. In other words, it forms the link between the bearing <NUM> and the housing <NUM>.

In this case, the ring-shaped element <NUM> includes at least two rings <NUM> which are adjacent to each other. Between the rings <NUM>, said damping elements <NUM> are provided, as described in detail below.

In the example of the figures and as clearly shown in <FIG>, there are six such rings <NUM>.

In this case, but not necessary for the invention, these rings <NUM> are made of steel or spring steel.

The rings <NUM> are also thin in the axial direction X-X', preferably with a thickness of up to five millimeters and preferably not more than two millimeters. In this case, the rings <NUM> are one millimeter thick. Of course, it is not excluded that the rings <NUM> are thicker than five millimeters.

According to the invention, the rings <NUM> are fitted with spokes <NUM>, which extend between the inner edge <NUM> and the outer edge <NUM> of the respective ring <NUM>.

This means that the rings <NUM> are not solid, but fitted with holes <NUM> or passages between the spokes <NUM>.

This not only reduces the weight of the rings <NUM>, but also ensures that the rings <NUM> and particular their spokes <NUM> possess a certain flexibility in the axial direction X-X'. In the radial direction X-X', the rings <NUM> are stiff.

The rings <NUM> are also oriented to ensure that the spokes <NUM> are mutually aligned.

Consequently, said holes <NUM> or passages are also mutually aligned so that the coupling element has <NUM> passages <NUM> through its axial thickness B.

However, this is not necessary for the invention, for example the spokes <NUM> of the three left-hand rings <NUM> could be aligned as well as the spokes <NUM> of the three right-hand rings <NUM>, while the spokes <NUM> of the three left-hand rings <NUM> are not aligned with the spokes <NUM> of the three right-hand rings <NUM>.

Between the aligned spokes, said damping elements <NUM> are provided, made of damping elastomer material. This is shown in the cross-section of <FIG>. In this case, the damping elements <NUM> take the form of block-shaped elements.

In this case, a damping element <NUM> is provided between all aligned spokes <NUM>, i.e. a damping element is attached to all spokes <NUM> of a ring <NUM>.

Of course this is not necessary, also if only half of the spokes <NUM> could be fitted with a damping element <NUM>.

In addition, a damping element <NUM> is provided between each pair of consecutive rings <NUM>.

This is not necessarily the case, it might also be that damping elements <NUM> are not provided between each pair of two consecutive rings <NUM>, but for example only between every other pair of rings <NUM>.

To sum up, it could be said that quantity of damping elastomer material that is provided between the spokes <NUM> can freely be selected in accordance with the specific application and required damping.

In this case, but not necessary for the invention, damping elements <NUM> are made of rubber.

The rubber is attached to or against the spokes <NUM> by vulcanization. The rubber may also be clamped between the spokes <NUM>.

As clearly shown in <FIG>, spacers <NUM> are provided between the inner edges <NUM> and the outer edges <NUM> of two consecutive rings <NUM>.

In this case, those are the narrow ring-shaped spacers <NUM>. Of course, it is clear that these spacers <NUM> can also be designed differently, for instance in the form of small blocks which are inserted along the circumference of the inner edges <NUM> and outer edges <NUM> between two consecutive rings <NUM>.

In order to keep the rings <NUM> of coupling element <NUM> together, the bearing damper <NUM> in the example of <FIG> is provided with both an inner clamping strip <NUM> and an outer clamping strip <NUM>.

It is possible that only the inner or outer clamping strip <NUM>, <NUM> is provided. However, in most cases both clamping strips are required <NUM>, <NUM>.

The inner clamping strip <NUM> holds the rings <NUM> together along their inner edge <NUM> and the outer clamping strip <NUM> holds them together along their outer edge <NUM>.

Making the clamping strips <NUM>, <NUM> wider or narrower in the axial direction X-X', will make it possible to join more or fewer rings <NUM> into a ring-shaped element <NUM> of the coupling element <NUM>.

As shown in <FIG>, the inner clamping strip <NUM> along the outside 20a has a rib <NUM> that runs all around and the outer clamping strip <NUM> has a similar rib <NUM> along its inside 21a.

These ribs <NUM> serve as a spacer between the two center rings <NUM> and thus form another embodiment of a spacer <NUM>.

Both the inner and outer clamping strip <NUM>, <NUM> may serve as the outer ring 23a or the inner ring 23b of the bearing <NUM>.

In the example of <FIG>, the bearing <NUM> of <FIG> is shown, which is provided with a bearing damper <NUM> as in <FIG>, wherein the inner clamping strip <NUM> serves as an outer ring 23a of a bearing <NUM>.

The inner ring 23b of the bearing <NUM> is mounted on the shaft <NUM> of the rotor <NUM> of the drive <NUM>.

Obviously, it is also possible that the outer clamping strip <NUM> serves as inner ring 23b of the bearing <NUM>, i.e. the bearing <NUM> is as it were around the bearing damper <NUM>, although this situation is less common.

Of course, it is also possible that the bearing <NUM> with its outer ring 23a is pressed into the inner clamping strip <NUM>. This has the advantage that a standard bearing <NUM> can be used.

Although in the example shown the clamping strips <NUM>, <NUM> and the rings <NUM> are separate elements or components of the bearing damper <NUM>, it is not excluded of course, that said elements are either one assembly or made as one piece.

The operation of the bearing damper <NUM> is very simple and as follows.

Bearing <NUM>, with bearing damper <NUM>, of <FIG>, is integrated into the housing 2b of the compressor element <NUM>, wherein the bearing <NUM> will be supporting shaft <NUM> of rotor <NUM>.

While compressor element <NUM> is in operation, axial vibrations or oscillations will occur, while the shaft <NUM> will move in the axial direction X-X'.

As a result, the bearing <NUM> and the inner clamping strip <NUM> of the bearing damper <NUM> will move according to the arrow C in <FIG>.

The outer clamping strip <NUM> will not move because it is installed static or secured in the housing 2b of compressor element <NUM>.

This relative movement of the inner clamping strip <NUM> relative to the outer clamping strip <NUM> will deform the flexible spokes <NUM> of the rings <NUM> as shown in <FIG>.

The magnitude of the axial displacement of the inner clamping strip <NUM> and, consequently, also the deformation of the spokes <NUM>, will depend, among other things, on the thickness A of the rings <NUM>, the number of spokes <NUM>, the quantity of damping elastomer material of the damping elements <NUM>. These parameters may be freely selected in advance, which makes it possible to determine in advance what the maximum axial displacement will be under the influence of said vibrations.

It is important to note here that the spokes <NUM> will only deform in the axial sense. In the radial sense, the spokes <NUM> are sufficiently rigid or non-deformable, so these allow little or no movement of the inner clamping straight <NUM> relative to the outer clamping strip <NUM>.

The deformation in the axial sense will deform the rubber between the spokes <NUM>. This causes the rubber to be subjected to shear stress.

As a result, the axial vibrations will be damped, as the forces will be absorbed by the spokes <NUM> and the rubber.

The bearing <NUM> itself will the subjected to much lower forces and stresses, since these will for the better part be absorbed by the bearing damper <NUM>.

Moreover, it will be possible to limit the axial movement of the shaft <NUM> due to the above vibrations, by choosing the appropriate stiffness and damping properties of the bearing damper <NUM>, since vibrations will be prevented from propagating any further into the motor and the compressor device.

This avoids problems due to these axial vibrations and the axial displacement of the shaft <NUM> further downstream in the machine.

<FIG> shows a variant of <FIG>, wherein in this case the coupling element <NUM> is only provided with two rings <NUM> that are not fitted with spokes <NUM>.

However, the inner and outer clamping strips <NUM>, <NUM> are still designed as broad as in the previous embodiment, for instance to facilitate assembly.

Another embodiment is shown in <FIG>, in which case the coupling element <NUM> only includes one ring <NUM>. This ring <NUM> may or may not contain spokes <NUM>.

An inner and an outer clamping strict <NUM>, <NUM> are also provided.

Both the inner and outer clamping strip <NUM>, <NUM> have a clamping surface <NUM> which extends in the axial direction X-X', between which the damping element <NUM> is installed.

In this case, there are two clamping surfaces <NUM> per clamping strip <NUM>, <NUM>, so also two damping elements <NUM>.

In this case, the damping elements are <NUM> ring-shaped, but this is not necessarily the case.

This relative displacement of the inner clamping strip <NUM> relative to the outer clamping strip <NUM> will cause the corresponding clamping surfaces to shift <NUM> relative to each other.

This causes the damping elements to deform <NUM>. As a result, the damping elastomer material will be subjected to shear stress. While in the previous example this involves a radial shear stress, in this example it is exerted in the sense X-X'.

<FIG> finally shows a variant of <FIG>, wherein in this case said clamping surfaces <NUM> extend in the radial direction.

For this purpose, the inner and the outer clamping strips <NUM>, <NUM> are provided with radial collars <NUM> or flanges.

The damping elements <NUM> which are located between the clamping surfaces <NUM> will be under compression load when the inner clamping strip <NUM> moves relative to the outer clamping strip <NUM>.

Although the examples shown and described above always refer to a compressor device <NUM>, the bearing damper <NUM> may also be used in other devices comprising a rotating shaft <NUM> which is carried by, or mounted in, the machine by means of a bearing <NUM>.

Claim 1:
Compressor device with a housing (<NUM>) and provided with at least one compressor element (<NUM>) and a drive (<NUM>) for the compressor element (<NUM>), wherein all bearings (<NUM>) of at least one shaft in the compressor device (<NUM>) configured to carry static axial load, are provided with a bearing damper (<NUM>) which comprises a coupling element (<NUM>) and at least one damping element (<NUM>),
wherein the bearing damper (<NUM>) is installed with the aid of the coupling element (<NUM>) between a bearing (<NUM>) of the compressor device (<NUM>) and the housing (<NUM>) of the compressor device (<NUM>),
wherein the coupling element (<NUM>) allows little or no movement of the bearing (<NUM>) relative to the housing (<NUM>) in the radial direction compared to the axial direction and
wherein the damping element (<NUM>) is configured to dampen the axial movement of the bearing (<NUM>) relative to the housing (<NUM>) characterized in that the damping element (<NUM>) is made of a damping elastomer material, the coupling element (<NUM>) is a ring-shaped element (<NUM>) which comprises at least one ring (<NUM>), and in that the ring-shaped element (<NUM>) is composed of at least two rings (<NUM>) adjacent to each other, with damping elements (<NUM>) provided between the rings (<NUM>).