TW201938916A - Vacuum pump and vacuum pump rotor - Google Patents

Abstract

A rotor and vacuum pump are disclosed for a vacuum pump. The rotor comprises: an outer profile and a hollow inner portion; at least one body within the hollow inner portion; and body constraining means for constraining the body. The at least one body being is such that movement in a direction parallel to a direction of rotation is constrained by the constraining means; and in response to a deceleration of the rotor that is greater than a predetermined critical value a predetermined force is exerted on the body that is sufficient to overcome the constraint exerted by the constraining means and the body moves within the hollow inner portion.

Description

Vacuum pump and vacuum pump rotor

The field of the invention relates to vacuum pumps and rotors for vacuum pumps.

The vacuum pump has a rotor that rotates at a high speed. If the rotors of this pump stop abruptly due to a failure or a sudden increase in pressure at the inlet, the force transmitted to the top plate through the short shaft and bearings can be large enough to break the screws holding the top plate to the stator, resulting in A permanent vacuum integrity loss. It is desirable to maintain vacuum integrity after this event and preferably during this event.

This problem has been previously solved using a lightweight rotor design to reduce the energy stored in the rotating block. This reduces the power given to other components of the pump during sudden deceleration and reduces the chances of the component breaking. However, lightweight rotors do have the disadvantage of greater deceleration during pumping (and possibly the next best pumping performance).

One further technique to solve this problem is the design of the deformable rotor profile, which can be used to extend the deceleration time. However, this may have one of the side effects of low inertia and may provide a profile that deforms under centrifugal loads, making it difficult to obtain good performance in a frequency range. One further technique that allows the fastener or top plate component to deform without breaking may help protect the pump to some extent, however, as the fastener or top plate component slides against each other, vacuum integrity may still be temporarily lost and may be permanent The same is true.

The present invention seeks to provide an alternative method that addresses at least some of the disadvantages listed above.

A first aspect provides a rotor for a vacuum pump, the rotor including: an outer profile and a hollow inner portion; at least one body within the hollow inner portion; and a body restraint member for restraining The main body; the at least one main body is mounted such that movement in a direction parallel to a direction of rotation is constrained by the constraining member; and in response to a deceleration of the rotor greater than a predetermined critical value, a predetermined is applied to the main body A force sufficient to overcome the constraint imposed by the constraint member and the body moving within the hollow interior portion.

The inventors of the present invention have realized that an elegant solution to the problem of a rotor's sudden deceleration transmitting force to other components of the pump and causing damage can be provided by providing a body in the rotor. The restraining or restricting member is held in place, but when the deceleration of the rotor exceeds a certain value, its structural design allows the restraining or restricting force to be overcome. This causes the main body to move inside the rotor, which moves the center of the block of the rotor and absorbs some kinetic energy, allowing the outer contour to decelerate rapidly, while the inner main body decelerates more slowly, resulting in a reduction in the overall transmission force. This absorption of some kinetic energy in the rotor helps protect the outer contour of the rotor and other components of the pump from damage.

The blocks of the restraining member and the body can be selected to have appropriate values so that only when one of the decelerations considered to be critical to the mechanical strength of the pump is reached, the force of the restraining member will be overcome and the body allowed to move.

The restraint member may be structurally designed in a variety of ways, but in some embodiments, the restraint member includes a deformable material that is structurally designed to deform under the predetermined force.

In addition to the movement of the main body to change the center of the block of the rotor, the deformation of the deformable material will also absorb some of the energy of the rotor.

In some embodiments, the deformable material is structurally designed to deform by one of bending, compression, and stretching.

In some embodiments, the restraining member includes a post extending in a radial direction, the main body is mounted on the post, and the post is structurally designed to deform in response to the deceleration above the predetermined threshold.

One way of restraining the main body may be to install it on a pillar which is structurally designed such that when a certain force is applied to the post it will deform and the main body will move within the hollow portion of the rotor, and the main body's movement will be extended Deceleration time and the bending of the column absorbs some energy.

In some embodiments, the post is attached to the rotor at a point towards a center of the rotor and extends towards the outer contour.

One way to allow the guide to bend is to attach a guide that can be a post to the center of the rotor and free the outer end. If the guide or column is properly structurally designed, a force on the body due to a sudden deceleration will cause the column to bend and the deceleration of the block inside the rotor will be slower than the deceleration of the outer contour.

In some embodiments, the body is mounted on the post at a position facing the outer contour.

Mounting the main body towards the outer edge of the rotor may be advantageous because in this position, the movement of the main body has a greater effect on the moment of inertia of the rotor and therefore can absorb more energy. In addition, many rotors are shaped so that their cross-sections can be larger towards external locations, allowing the body to move further within the rotor.

In some embodiments, the column is structurally designed to have at least one predetermined portion weaker than other portions of the column such that, in response to the critical velocity change rate, the guide preferentially deforms at the at least one predetermined portion.

It would be desirable to provide further control of the deceleration of the body, and this may be provided by designing the guide structure to have a weaker part than other parts of the guide. This makes it possible to control the deformation or bending of the guide in response to deceleration, and the movement of the block within the rotor follows a predetermined path. This protects the outer contour of the rotor from excessive damage in response to at least some deceleration.

In some embodiments, the body is mounted to slide between an internal position and an external position on the post in response to a change in a rotational speed of the rotor.

When the main body is mounted on a post, in addition to providing some protection against sudden deceleration by allowing the post to deform, the post can also be used as a guide along which the main body can slide and thereby change the moment of inertia of the rotor. . In this regard, the nature of a rotor changes with the operation of the pump. Therefore, during startup, for example, in the case of a pump to be accelerated, a low inertia rotor will accelerate faster. However, when operating at full speed, a rotor with a high moment of inertia will be more resistant to interruptions due to pressure changes, and will slow down more slowly in response to such changes. A body that is mounted so that it slides in response to the speed of rotation within the rotor can be used to provide a rotor with a lower moment of inertia at a lower rotation speed in which the body faces the center of the rotor, and an outer portion in which the body faces the rotor One of the higher speeds has a higher moment of inertia. In this regard, a biasing member may be used to bias the body toward an internal position, thereby allowing the body to move to an external position when a speed above a certain level is reached. In the case where the main body is in the outer position, the force attributable to deceleration will be higher on the column and more likely to deform. When the rotor is rotating at or towards full speed, the protection of the rotor due to a sudden deceleration event is particularly important.

Alternatively and / or additionally, the restraint member includes a compressible material mounted within the hollow interior portion.

If the restraining member holds the main body in place until a predetermined force is exerted on the main body triggered by a sudden deceleration, the main body can be restrained in various ways, and this force is sufficient to overcome the restraining force. In some cases, the constraining member may be a compressible material such that the body is mounted in a hollow rotor, in some cases toward the trailing edge of the outer contour, where the compressible material is located between the body and the leading edge of the outer contour. The compressible material is structurally designed such that it compresses in response to a predetermined force and the body moves from the trailing edge toward the leading edge of the outer contour of the rotor.

In other embodiments, the restraining member includes a biasing device that attaches the body to the outer contour and is structurally designed to move by tensile deformation in response to a force greater than or equal to the predetermined force.

An alternative and / or additional member to restrain the body may use a biasing member (such as a spring) that holds the body near the trailing edge of the outer contour and is structurally designed to stretch or compress the body in response to a predetermined force Move towards the leading edge of the outer contour. In some embodiments, the body may be mounted in or on some guide members to guide its path within the rotor from the trailing edge to the leading edge.

In some embodiments, the outer profile of the rotor is substantially lighter than the at least one body.

The embodiment may be particularly effective if the main body has a substantial block with respect to the block with the outer contour. In this case, due to the inner body moving from a position near the trailing edge of the rotor towards a position near the leading edge within the outer contour, the slower deceleration of the inner body has a greater effect on the absorption of kinetic energy and therefore results in One of the forces transmitted to the other components of the pump is reduced.

In some embodiments, the outer contour is more resistant to deformation than the restraining member.

Although it may be advantageous to have a relatively light outer profile compared to the main body, it would be desirable for the main body to be mechanically stable and due to deceleration forces to be more resistant to deformation than restraining members within the profile, so that it responds to sudden deceleration , It is a deformation restraint member rather than the outer contour. Where the outer contour is mechanically stable, it may not be damaged by deceleration and may be reused, although in some embodiments the entire rotor needs to be replaced after this event.

In some embodiments, the rotor includes a fluid flow path between a front side and a tail side of the rotor, the body is mounted to obstruct the fluid flow path in a closed position, and is responsive to one of the rotors. The deceleration exceeds a first value and moves to an open position without hindering the fluid flow path.

In some embodiments, a movable body within the rotor may also be used as a valve member for obstructing or opening a flow path through the rotor. In this regard, the body forms part of a pressure relief valve within the rotor itself to allow fluid to flow from the leading edge to the trailing edge of the rotor in response to a sudden high pressure event. Within the rotor is a movable body that is structurally designed to move in response to a sudden deceleration, providing the opportunity to use the body not only to reduce the speed of deceleration of the entire rotor, but also to open a valve in the rotor and release some pressure increase. Sudden deceleration is usually caused by an increase in pressure, and therefore it may be advantageous to provide some pressure relief.

In some embodiments, the restraint member is an elastic restraint member, and the body can open the valve in response to a first predetermined deceleration and return to its closed position when the deceleration ends. In this way, the protection of the rotor can be improved. In some embodiments, in response to a higher deceleration, the elastic member may be further deformed, in some cases exceeding its elastic limit and the body will move further, thereby providing deceleration or absorption of kinetic energy, which provides at least some Protected against damage to the pump and rotor. In some embodiments, the first value and the critical value are the same value.

In some embodiments, the rotor includes at least two restraint members, a first restraint member is structurally designed to allow the body to move a short distance in response to the deceleration exceeding the first value, and a second restraint member passes The structure is designed to allow the subject to move a further distance in response to the deceleration exceeding the critical predetermined value.

In the case where the rotor has a movable body that functions both as a valve body and as a protective member to prevent sudden deceleration, it may be advantageous to use two different restraining members. This configuration can be structured to allow the body to move a short distance under a first small force to open the valve and move a further distance under a larger critical force to absorb more deceleration energy.

The two different constraint members can be several things, as long as their equal constraints are overcome by forces of different magnitudes, allowing a first movement in response to a smaller force and a further movement in response to a higher force. In some embodiments, the first restraint member includes a shape of an internal space of the rotor in which the main body is mounted, such that the main body is restrained by a centrifugal force applied to the main body to hinder the main body from rotating when the rotor rotates The fluid flow channel.

The first restraining member can simply be the shape of the space in which the main body is installed, and its shape is such that when the rotor rotates, the main body is thrown into a position where the fluid flow path is blocked by centrifugal force. Deceleration of the rotor moves the body away from this position and opens the path. Further movement beyond this initial open position is constrained by a second restraint member, which requires a further force to allow the body to move further.

In other embodiments, the first restraint member and the second restraint member include a deformable material, and the deformable material of the first restraint member is structurally designed to deform under a first force and the second restraint member The deformable material is structurally designed to deform under a second higher force.

In some embodiments, the deformable materials of the first restraint member and the second restraint member are each structurally designed to deform by one of bending, compression, and stretching.

A second aspect provides a vacuum pump including a rotor according to a first aspect.

In some embodiments, the rotor includes a two-bladed rotor, one of the blades includes one of the at least one body.

In some embodiments, the vacuum pump includes a mechanical boost pump.

In some embodiments, the vacuum pump includes a twin-rotor Roots pump.

Further special and preferred aspects are described in the accompanying independent and subsidiary technical solutions. The features of the subsidiary technical solution and the features of the independent technical solution may be combined as appropriate and in combination with these features except those explicitly stated in the technical solution.

Where a device feature is described as operable to provide a function, it will be understood that this includes providing a device feature that is adapted or configured to provide a function.

Before discussing the embodiments in more detail, an overview will first be provided.

A rotor for a mechanical supercharger is disclosed, which has an energy absorbing core to reduce the load transmitted to the shaft and the top plate during a sudden deceleration (timing slip) without excessively reducing the rotor inertia.

The rotor profile is structurally designed to be relatively light, but still strong enough to maintain its shape under centrifugal loads encountered during normal operation. In some embodiments, a separate "lollipop" built into the chamber is used to maintain inertia, which is often referred to as a relief hole. In a sudden deceleration event, the outer contour stops quickly, but due to its low inertia, it does not transmit very large loads to the stubs, bearings or roof. A lollipop including a block installed at the end of a column extending from a central portion of the rotor initially continues to rotate and decelerates over a period of time longer than the outer contour by bending its stick. Energy is absorbed by the rod, and extended deceleration reduces the force transmitted to the top plate.

In some embodiments, the outer contour is structurally designed to be mechanically stable so that it will not deform under the force of a lollipop column deformation and the damage is limited to the lollipop, so that the contour can be reused after replacing the damaged part.

Almost all existing solutions to this problem involve reducing the weight of the rotor, and do not take into account the associated loss of pumping efficiency that this will cause.

The lollipop stick or column can be weakened in an advantageous position, so that the head of the lollipop has a large range of movement without colliding with the inner edge of the outer contour.

FIG. 1 shows a rotor 5 including an outer contour 10 and a main body 20 mounted on a post 30 according to an embodiment. The post 30 and the main body 20 are structurally designed such that in response to a deceleration exceeding one of a predetermined threshold value, the post 30 will bend and the main body 20 will move from its center position toward the leading edge of the rotor. In this way, compared to the case where some internal movement of the block does not exist in the rotor, the time for the deceleration to occur and the force transmitted to the other components of the pump will be reduced.

In some embodiments, the body 20 is also structurally designed to slide along the column 30, allowing the inertia of the rotor to change depending on the speed of rotation of the rotor. Therefore, depending on the speed of rotation, a centrifugal force applied to the body will change and at some point it will be sufficient for the body 20 to move from an internal position to the external position shown. In this regard, the body may be held in an internal position by a biasing member, such as a spring not shown. The biasing member is structurally designed to stretch such that the body moves to an external position in response to a force applied when the rotor is operating at or near full speed.

Therefore, when operating at full speed, the subject will be in the position shown in FIG. 1. Due to increased pressure or failure in the pump, the pump at full speed is at the greatest risk of being suddenly decelerated and damaged. Therefore, in the case where the body can slide along the column 30, they will be in the position shown in FIG. 1 at a higher rotation speed. In other embodiments, the body 20 will be mounted without moving in a radial direction. In either case, a sudden deceleration from full speed beyond a critical value will cause the pillar 30 to bend and will cause the pillar 30 to bend and the body 20 to move in response to the deceleration force.

In some embodiments, the post 30 is structurally designed to better deform at a certain point. This allows the movement of the subject in response to a sudden deceleration to be more predictable and controlled. Controlling it so that the body 20 does not contact the outer contour 10 in response to a deceleration at or near one of the critical post-curvature values may be advantageous, and therefore, the rotor outer contour may be reused.

FIG. 2 shows an alternative embodiment in which the restraining member is in the form of a compressible material 32. In this case, the deceleration force due to the rotor acting on the main body 20 will cause the main body 20 to press the compressible material 32. The compressible material may be structurally designed such that a specific force on the body 20 is sufficient to compress the material 32 and allow the body 20 to move.

FIG. 3 shows an alternative embodiment in the form of a restraint member in the form of a spring 34. In this embodiment, when decelerating, the spring will extend and the main body 20 will move within the internal space of the rotor. In this embodiment, there is a guide 36 for restraining the movement of the main body 20 in response to the deceleration force. In some cases, there may be openings in the outer contours 37a and 37b, which are blocked by the body 20 when in the restrained position. When not in the restrained position, the opening 37a is no longer obstructed and fluid can flow from one of the openings 37b in the leading edge of the rotor to one of the openings 37a in the trailing edge. In this embodiment, the flow path passes through the guide 36, which may be larger than the moving body 20, and in other embodiments, there may be an adjacent channel traveling between the openings. The flow path and the opening serve as a pressure release path and help to further reduce the deceleration force. In some embodiments, the spring is structurally designed to extend to the open opening 37a within its elastic limit in response to a first deceleration force. If the deceleration force is greater than a second critical value, the spring can extend beyond its elastic limit and the body will move further and the movement will absorb some kinetic energy.

In some embodiments, the restraint member may be a combination of one or more of the restraint members disclosed in FIGS. 1 to 3. For example, in the embodiment of FIG. 3, a compressible material may be present in the guide toward the leading edge, which can cushion the body and slow its movement when the spring moves a certain distance (in some cases exceeding its elastic limit). . Similarly, compressible material may be present in the hollow interior space of the rotor of FIG. 1 or the body in the embodiment of FIG. 2 may be attached to the trailing side of the outer contour of the rotor by a spring member. Using different elastic members to prevent movement of the main body 20 may allow different critical rotational speeds to trigger the movement in different amounts. This can be used to provide limited motion sufficient to open the pressure relief valve at a first deceleration and provide further movement of the subject with a higher deceleration. Further movement may cause permanent deformation of the elastic member and in some embodiments may cause damage to the rotor.

FIG. 4 shows this embodiment in which a rotor has two restraining members for the main body 20, and a first restraining member 34 includes a spring that is structurally designed to deform a short distance in response to a first force, thereby Port 37a is open and provides a passage through rotor 5 to inlet 37b. In response to a large deceleration force, the restraint member 34 deforms beyond its elastic limit and the main body 20 moves to contact the compressible material 32, which acts as a collision pad to receive the main body 20 and compress to allow the main body 20 to move toward the leading edge of the rotor and Absorb some slowing energy.

In an alternative embodiment of the embodiment shown in FIG. 4, the spring 34 may be absent and the body 20 may simply be constrained by the internal shape of the rotor to block the port 37a when the rotor is rotating and centrifugal force is applied to the body. In this case, the deceleration will cause the main body 20 to move away from the port 37a and the fluid flow path through the rotor will be opened. Further movement of the body will be restricted by the compressible material 32. A higher deceleration force may be sufficient to compress the material and the body will move further into the material to absorb some kinetic energy.

In summary, Figure 1 shows a device designed to absorb energy by bending, and Figure 2 shows a device that absorbs energy by compression. Figure 3 shows a device that absorbs by a tensile deformation. Figure 4 shows an embodiment with two restraining members, where in one example one is deformed by stretching and the other is deformed by compression.

The skilled person will recognize that the restraint members may be formed in different ways. In the case where the main body in the rotor also serves as a valve body, the restraint member can be structurally designed so that an initial movement occurs at a lower force, allowing the valve to open, while further movement can occur at a higher force and is energy absorption. The restraining member used in the embodiment may be formed of a deformable material that can deform and absorb energy under any one of bending, compression, and tensile deformation.

Although the illustrated embodiments of the present invention have been disclosed in detail herein with reference to the accompanying drawings, it should be understood that: the present invention is not limited to the precise embodiments; and those skilled in the art may Various changes and modifications are realized herein without departing from the scope of the invention as defined by the equivalents.

5‧‧‧ rotor

10‧‧‧ outer contour

20‧‧‧ Subject

30‧‧‧columns

32‧‧‧ Compressible material

34‧‧‧Spring

36‧‧‧Guide

37a, 37b ‧‧‧ opening

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

Figure 1 shows a rotor according to a first embodiment;

Figure 2 shows a rotor according to a further embodiment;

FIG. 3 shows a rotor according to a still further embodiment; and

Fig. 4 shows a rotor according to yet another further embodiment.

Claims (21)

A rotor for a vacuum pump. The rotor includes: An outer contour and a hollow inner part; At least one body within the hollow interior portion; and A restraint member for restraining the subject; The at least one body is installed such that movement in a direction parallel to a rotation direction is restricted by the restraining member; wherein, In response to the deceleration of the rotor being greater than a predetermined critical value, a predetermined force is applied to the body, the force being sufficient to overcome the constraint imposed by the restraint member, and the body moves within the hollow interior portion. The rotor of claim 1, wherein the restraining member includes a deformable material that is structurally designed to deform under the predetermined force. The rotor of claim 2, wherein the deformable material is structurally designed to be deformed by one of bending, compression, and stretching. The rotor of claim 1, wherein the restraining member includes a column extending in a radial direction, the main system is mounted on the column, and the column is structurally designed in response to the deceleration being higher than the predetermined threshold value, Deformation. The rotor of claim 4, wherein the post is attached to the rotor at a point toward a center of the rotor and extends toward the outer contour. The rotor of claim 4, wherein the main system is mounted on the post at a position facing the outer contour. As in the rotor of claim 4, wherein the column is structurally designed to have at least one predetermined portion weaker than other portions of the column such that, in response to the critical velocity change rate, the guide is preferentially deformed at the at least one predetermined portion. The rotor of claim 4, wherein the body is mounted to slide between an internal position and an external position on the post in response to a change in one of the rotational speeds of the rotor. The rotor of claim 1, wherein the restraining member comprises a compressible material which is installed in the hollow inner portion and is structurally designed to be compressed in response to a force greater than or equal to the predetermined force. The rotor of claim 1, wherein the restraining member includes a biasing member that attaches the main body to the outer contour and is structurally designed to respond to a force greater than or equal to the predetermined force by stretching Transform to distort. The rotor of claim 1, wherein the outer profile of the rotor is substantially lighter than the at least one body. The rotor as claimed in claim 1, wherein the outer contour is more resistant to deformation than the restraining member. As in the rotor of claim 1, the rotor includes a fluid flow path between a front side and a tail side of the rotor, the body is mounted to obstruct the fluid flow path in a closed position, and responds to the rotor A deceleration exceeding a first value moves to an open position without obstructing the fluid flow path. As the rotor of claim 13, the rotor includes at least two restraint members, a first restraint member is structurally designed to allow the subject to move a short distance in response to the deceleration exceeding the first value, and a second restraint member The structure is designed to allow the subject to move a further distance in response to the deceleration exceeding the critical predetermined value. The rotor of claim 14, wherein the first restraining member includes a shape of an internal space of the rotor in which the main body is installed, the shape such that the main body is subjected to a centrifugal force applied to the main body when the rotor is rotated. Constrained to obstruct the fluid flow channel. The rotor of claim 14, wherein the first restraint member and the second restraint member include a deformable material, the deformable material of the first restraint member is structurally designed to deform under a first force, and the second The deformable material of the restraint member is structurally designed to deform under a second higher force. The rotor of claim 16, wherein the deformable material of the first restraint member and the second restraint member are each structurally designed to be deformed by one of bending, compression, and stretching. The rotor of claim 1, wherein the rotor comprises a double-blade rotor, each of the blades comprising one of the at least one body. A vacuum pump comprising a rotor as claimed in claim 1. The vacuum pump of claim 19, wherein the vacuum pump comprises a mechanical boost pump. The vacuum pump of claim 19, wherein the vacuum pump includes a twin-rotor Roots pump.