MXPA99002277A - Bearing isolator with air purge - Google Patents

Abstract

This invention discloses an improved seal utilizing an air purge to remove contaminants. The seal (1) is most useful on spindles (10) and utilizes a combination locking ring and diffuser ring (18) to diffuse the air within the seal (1) member itself. The pressurized air is passed from the diffuser (18) into at least one cavity or chamber (31) which is within the rotor of the seal (1) and which, because of its rotation as the rotor, provides a centrifuging effect to efficiently and completely remove contaminants, including the liquid or air, and thus preventing the contaminants from reaching the bearings which the seal or bearing isolator is protecting. The bearing isolator or seal element will operate efficiently with or without air pressure, but operates more efficiently with a very small air pressure applied to the diffuser (18) and locking element.

Description

BEARING INSULATION WITH AIR PURGE BACKGROUND OF THE INVENTION 1) Field of the invention The field of this invention is the sealing of the bearings especially in high speed peripheral applications where contaminants are present, and these must be isolated from the bearings. 2) Related Technique Machine tool spindles, due to their high-speed rotation, create requirements for maximum reduction or total elimination of contaminants that interact with the bearings and consequently are a continuing problem for joint and spindle manufacturers. It has long been the belief among joint manufacturers that the addition of air purge could improve the protection of the bearings, for example by using a sealing mechanism in conjunction with an air purge. In the prior art lip seals and labyrinth patterns have been REF. 29680 combined with an air purge. The air purge pressure has typically been between 0.35 and 0.49 kg / cm2 (5 and 7 psi) and has been inserted either from the inside or outside or in the middle part of the labyrinth pattern of the lip seal. These labyrinth patterns in the lip seals in combination with seals or seals are not and have not been very satisfactory. This is especially true where the seal or seal is subject to a large amount of flooding and shock with the refrigerant, in which case a substantial amount of the refrigerant may be collected in the area between the labyrinth pattern and the lip seal. The lip seal is then substantially the only sealing member between the bearings and the collected contaminants and the refrigerant. The lip seal, due to pressure and friction, is subject to a substantial amount of wear and the sooner or later entry of contaminants or coolant beyond the lip seal, has always occurred. The speed of rotation is a factor that affects all sealing devices, and lip seals will operate better at lower peripheral speeds and with a shorter period of time than seals or joints of another type. The air purge has been operated with bearing insulators, similar to those shown and described in US Patent No. 5,378,000 but with limited success. Previous air purges have directed external air to the bearing insulators and the bearing insulator has now merely replaced the lip seal. This arrangement has at least two disadvantages and has not been completely successful because directing the air purge in front of the thermal insulator causes the air, including the refrigerant and the waste, due to the pressure, to pass through the insulator and towards the bearing housing. Any pieces or thin metal particles will be trapped by the air pressure around the bearing insulator and will cause increased wear and reduce the efficiency of the bearing. Another system to use air, to theoretically improve the sealing mechanism of the bearing insulators, has been to pressurize the housing. The pressure is normally between 0.07 and 0.14 kg / cm2 (5/10 and 2 psi) and is generally introduced at the midpoint of the housing between the bearings. This configuration, when air is properly applied, is compatible with a bearing insulator. However, in that air is being introduced directly into the bearings, air cleaning is extremely important. It is also extremely important to restrict the maximum internal pressure to prevent the lubricant from coming out or exiting and the temperature increases in the bearing insulator. It has now been shown that this addition of pressure to the bearing housing improves the operation of the bearing insulator, particularly with slow peripheral or static axes. Another example of air combined with the use of bearing insulation, has been to introduce the air from inside the bearing insulator, and try to seal the air from the housing by a normal lip seal or other restriction devices. A gate could allow the escape of water or other contaminants contained in the air purge. In this design, the lip seal or other restriction device is still the critical member and limits the life and quality of the sealing effect. This configuration is also mainly satisfactory with the slower peripheral speed of the spindles or axes. Thus, it is important to have a sealing system without using a lip seal and simultaneously being able to use an air supply which is not necessarily pure, for example, may contain contaminants including fluids. The contaminants will migrate beyond any lip seal, especially at high peripheral speeds.

BRIEF DESCRIPTION OF THE INVENTION This invention is designed to keep contaminants away from the bearings with a bearing insulator, and a novel air purge mechanism. The ability to use air pressure to improve sealing, while insulating bearings from air pressure and any contaminants contained therein, is the basic improvement of this invention. This invention provides an improved sealing mechanism, whereby, with the positive expulsion of the contaminant, the seal will have a long service life even at high speeds. This invention also provides positive expulsion of the contaminant when the axis is at rest. The housings containing bearings are sometimes operated at slightly lower pressure, for example, below atmospheric, than the external pressure on the housing. In this invention, the faces of the rotor and the stator limit one with the other and are axially secured together. This invention provides a peripheral high speed sealing mechanism even if the basic seal ring of the seal is raised, the air pressure reinforces the seal or seal and provides a positive seal mechanism at all times. The air purge system is designed to come out of the sealing mechanism, to expel contaminants and vent the seal or gasket. The seal or seal mechanism of this invention can be without air pressure in a static or dynamic condition but will continue to prevent the influx of contaminants into the bearings. If the air flow is suspended, interrupted, or not used, the seal insulator or bearing seal will operate in a normal manner to prevent the entry of contaminants into the bearing area.

DESCRIPTION OF THE DRAWINGS Figure 1 is a sectional view showing in detail the seal or seal assembly within the housing, including the air system to assist in sealing.

DETAILED DESCRIPTION OF THE INVENTION The novel seal or gasket 1 of this invention is shown with a stator 13 fixed to the housing 9. The rotor 14 is fixed to the shaft 10 and driven by the ring members 17. The novel seal or gasket mechanism of this invention may or may not include the seal 16 sealing between the housing 9 and the stator 13. The shaft 10 extends through the housing 9 and is surrounded by the seal 1 including the stator 13 and the rotor 14. The rotor 14 is fixed to the shaft 10 and is rotated with the shaft 10 by the drive members or ring 17. The sealing ring 22, including the cavities 21 and 25 and the corresponding labyrinths formed in the rotor 14 and the stator 13, act to effectively seal the entry or the discharge of the materials including the contaminants, into the cavity 31 of the housing 9. Those elements of this novel seal were present in the prior art. The improvements provided by this novel seal include the use of air pressure from an air pressure source 15 which is connected to the air cap 12. The cover 12 may be capped or allow air pressure to enter. through the space 12 of the cover towards the channel or the air passage 19. The air under pressure, whose pressure could normally be between 0 and 0.7 kg / cm2 (0 and 10 psi), is then directed towards the diffuser ring 18 to ensure that the air pressure is uniformly distributed around the periphery of the seal 1 and inside the first air chamber or cavity 21. The diffuser ring 18 also secures the rotor 14 and the stator 13 together to limit axial movement between the rotor 14 and the stator 13. The face 32 between the stator 13 and the rotor 14 is held in place by the ring 18. The diffuser ring 18 has passages 18a connecting the passage 19 to the cavity 21. The securing force between the rotor 14 and The stator 13 is provided by the diffuser 18. The diffuser 18 borders the stator 13 and the rotor 14, and is also retained against the stator 13. A first air chamber 21 is also provided and the air coming from the diffuser 18 moves towards the air chamber 21 and then moves by a centrifugal action including the blade 24 within the second air chamber or cavity 25, and is centrifuged again by the action of the cavity 25 and the second blade 23, to move the contaminants and / or any liquids towards the outside of the cavities or chambers 21 and 25, and may be drained through a drain or drain 41 which can be placed anywhere on the insulator, but preferably at the bottom or at the 6 o'clock position of the bearing insulator. The waste can also be expelled through the outlet 35 formed by the passage 35 between the rotor 14 and the stator 13. The air flow between the static conditions will flow out of the outlet by gravity and the air without centrifuging. If the shaft 10 is not rotating or is static, then gravity and drainage by air flow will evacuate the air chambers 21 and 23 from any and all contaminants, and thus, prevent them from entering the bearing housing. When no air is applied to the seal or seal 1 through the air passage 19 from the air pressure source 15 and / or the cover 12 is inserted into the air passage 19, then the seal 22 will continue to act as a way of restriction to ensure that any air or contaminants in the air chambers 21 and 25 come out to the outside. The sealing ring 22 presents a restriction path for any air or contaminant in the chambers 21 and 25. The air or contaminants will still be expelled out through the outlet 35 or out of the drain 41 by gravity. In operation, as the drive rings 17 drive the motor 14 and the air pressure from the source 15 is provided through the cover 12 and the air inlet 19, the diffuser 18 will project this air into the air chamber 21. which provides an area of little resistance for the movement of the contaminants towards the chamber 21 and outwards through the centrifugal movement. Meanwhile, the sealing ring 22, together with the obstruction and / or the labyrinths formed by the cavities 21 and 23 between the stator 13 and the rotor 14, will always act to inhibit the movement of any contaminants towards the bearing housing 31. The air pressure and the amount of air required is significantly less than the pressure in any of the known air purge systems. Also, due to the ability to centrifuge out any contaminants included with the air supply, a less expensive lower quality air source can be used, which was not possible with the prior art air and ventilated systems. If the air system has been operational and some failure of the air system occurs, the bearing insulator of this invention will continue to operate satisfactorily as a seal or gasket. The addition of air does not provide improved protection and sealing of contamination using only a slight difference in pressure and / or temperature through the bearing insulator. The outlet 35 and / or the drain 41, which offer little resistance to the flow of the liquid, improved by the centrifugal action, forces the contaminants and the liquid out of the less restrictive outlet and / or the drain 41. This seal or Bearing gasket will operate more reliably under all conditions. This requires a lower pressure and a smaller amount of air applied to the diffuser ring 18 to obtain the improved seal. Having described the preferred embodiment, other features of the present invention will undoubtedly be apparent to those skilled in the art, as will numerous modifications and alterations in the embodiments of the illustrated invention, all of which can be achieved without departing from spirit and scope. of the invention as defined in the appended claims.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Claims (18)

CLAIMS Having described the invention as above, the following content is claimed as property:

1. A seal or seal for an axle exiting a housing, characterized in that it includes: a) a housing: b) an axle extending through said housing; c) a seal or seal fixed to the housing and surrounding the shaft; and d) the seal comprising: 1) a stator fixed to the housing 2) a rotor rotating with the shaft; 3) the stator that includes a passage between the housing and the rotor; 4) A locking mechanism to prevent axial movement of the rotor with respect to the stator; 5) A plurality of cavities that act as a centrifuge for the liquid that includes contaminants, with the passage of the liquid centrifuged to the outside or to the seal or joint to eliminate contaminants; and 6) A passage from the cavities so that the flow of the centrifuged liquid and contaminants leaves said seal or joint.

2. The seal or seal according to claim 1, characterized in that the securing mechanism includes a plurality of passages connecting the passage towards the housing towards the plurality of cavities.

3. The seal according to claim 1, characterized in that the plurality of cavities includes at least one first cavity formed in the rotor.

4. The seal according to claim 1, characterized in that the plurality of cavities includes at least a second cavity formed between the stator and the rotor.

5. The seal according to claim 2, characterized in that the securing mechanism includes a central passage connected to each of the plurality of passages in the securing mechanism.

6. The seal according to claim 1, characterized in that the passage for the centrifuged liquid includes the passage between the rotor and the stator.

7. The seal according to claim 1, characterized in that there is a drain for removing the centrifuged liquid from the second cavity towards the exterior of the seal or seal.

8. The seal according to claim 1, characterized in that the first cavity has a blade to help centrifuge the liquid.

9. The seal according to claim 1, characterized in that the second cavity has a blade to help centrifuge the liquid.

10. A seal or seal for an axis that leaves a housing, characterized in that it includes: a) a housing; b) an axis extending through the housing; c) a seal or seal fixed to the housing and surrounding the shaft; and d) the seal comprises: 1) a stator fixed to the housing; 10 2) a rotor that rotates with the shaft; 3) the stator that includes a passage between the housing and the rotor; 4) an assurance mechanism to prevent axial movement of the rotor 15 with respect to the stator; 5) the securing mechanism that includes a central passage and a plurality of passages connected to the central passage; 6) a plurality of cavities for centrifuging the liquid; and 7) at least one passage for the centrifuged liquid to leave the seal. or board; e) a source of pressurized liquid; f) the passageway in the housing is connected to the source and the central passageway of the securing mechanism; g) the securing mechanism has its plurality of passages connected to the cavities, with which the pressurized liquid is centrifuged, after the passage leaves the seal or joint, and removes the contaminants.

11. The seal according to claim 10, characterized in that the central passage is connected to the plurality of passages.

12. The seal according to claim 10, characterized in that the plurality of cavities includes at least a first cavity formed in the rotor.

13. The seal according to claim 10, characterized in that the plurality of cavities includes at least a second cavity formed between the stator and the rotor.

14. The seal according to claim 10, characterized in that the passage to the outside of the seal is a passage between the rotor and the stator.

15. The seal according to claim 10, characterized in that the drain connects the second cavity towards the exterior of the seal.

16. The seal according to claim 10, characterized in that the first cavity has a blade to help centrifuge the liquid and eliminate contaminants.

17. The seal according to claim 10, characterized in that the second cavity has a blade to help centrifuge the liquid and eliminate contaminants.

18. The seal according to claim 10, characterized in that the passageway in the housing that connects the source of the pressurized liquid to the central passageway is closed.