WO1995000780A1

WO1995000780A1 - Self-aligning shaft support

Info

Publication number: WO1995000780A1
Application number: PCT/AU1994/000129
Authority: WO
Inventors: Dmitry Cherny; Nicolai Cherny; Dimitry Cherny
Original assignee: Cherny Holdings Ltd
Current assignee: Cherny Holdings Ltd
Priority date: 1993-06-23
Filing date: 1994-03-17
Publication date: 1995-01-05
Anticipated expiration: 1995-12-23

Abstract

An apparatus for controlling the movement between a shaft (12) and a housing (10). A guide (22) controls the rotation and reciprocation of the shaft (12) relative to the housing (10). A flange (32) is connected to the guide (12), a bearing (34) rests between the flange (32) and an axial surface (38) of the housing (10), and a spring (44) urges the flange (32) against the bearing (34) for contact with the axial surface (38) of the housing (10). The operation of these components cooperate to furnish an apparatus that permits rotational and reciprocal movement of the shaft (12), and further permits transverse and angular movement of the shaft (12) relative to the housing (10).

Description

SELF-ALIGNINGSHAFTSUPPORT

The present invention relates to an apparatus for controlling a shaft as it moves relative to a housing. More particularly, the invention relates to a shaft support arrangement that simultaneously permits rotation, reciprocation, transverse movement, and angular movement of the shaft relative to the housing.

Many tools incorporate a shaft that moves relative to a housing. In these tools, the housing typically guides and supports the shaft in a rotational or reciprocating motion. In oil wells, a beam pump reciprocates a pull rod connected to a downhole pump for lifting the hydrocarbon fluids to the surface. The upper section of the pull rod is guided by a housing that incorporates a seal such as a stuffing box to seal the annulus between the housing and the pull rod. The movement of the beam pump causes the pull rod to reciprocate relative to the housing. In addition to this reciprocal motion, misalignment of the pull rod can urge the pull rod in directions transversely and angularly relative to the center axis of the housing.

Any shaft movement in a direction other than a reciprocal or rotational direction urges the shaft against one side of the seal and accelerates seal wear. If the shaft is urged transversely relative to the shaft axis, the seal will wear excessively on one side. If the shaft moves in an angular direction relative to the shaft axis, the seal will simultaneously experience excessive

wear on opposing ends of the seal on opposite sides of the shaft.

Similar problems exist in other applications combining a shaft and a housing, such as in the pull rods used in windmill driven water wells. In these wells, the rotational movement of the windmill blades can rotate a shaft driven water pump, or can be converted into a reciprocal movement for operating a pull rod. In either application, the shaft can become misaligned with the housing and induce excessinve wear on the shaft, housing, and any seals.

In other applications combining a shaft and a housing, the rotational movement of a shaft within a housing can become unbalanced if the shaft clamps loosen or if the shaft is accidentally bent. This misalignment can create vibrational forces destructive to the housing and engaged machinery. Additionally, many industrial processes utilize a rotating shaft that reciprocates within a housing to perform a desired motion, such as in the positioning of components in manufacturing processes. In these applications, bearings can control the rotation of the shaft, and seals can control the retention of lubricating fluids adjacent the shaft. If forces move the shaft transversely or angularly relative to the shaft axis, the corresponding forces translated to the bearings or the seals may cause bearing failure or excessive seal wear.

Accordingly, a need exists for an improved apparatus for permitting motion of a shaft relative to a housing. The invention should permit rotational and reciprocating movement of

the shaft, and should simultaneously compensate for transverse and angular movement of the shaft relative to the shaft axis.

SUMMARY OF THE INVENTION

The present invention provides a unique apparatus for controlling the movement of a shaft. The invention comprises a housing having an axis and having an axial face within the interior space of said housing. A guide is located within the housing and has an axial passage for controlling the shaft in a direction substantially parallel to the axis of the housing. A flange is connected to the guide in a plane substantially perpendicular to the axial passage through the guide, and ?. bearing is in contact between the flange and the axial face of the housing. A spring engaged between the housing and the flange urges the flange against the bearing.

In other embodiments of the invention, the spring can comprise a hydraulic ram or a coiled spring. The axial face of the housing can be beveled to prevent migration of the bearing, and the axial face of the housing can be spherical to permit angular movement of the guide relative to the housing. A seal can be^•located between the moving components, and the force exerted by the spring can be adjustable to modify the force urging the flange in contact with the bearing and housing. BRIEF DESCRIPTION OF THE DRAWING

Figure 1 illustrates a sectional view of one embodiment of the invention. Figure 1 illustrates a coiled spring to urge a flange into contact with a bearing and a housing. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention furnishes an improved apparatus for controlling the movement between a shaft and a housing. Figure 1 illustrates an apparatus useful in reciprocating or rotating pump units such as those used in water wells. As illustrated, housing 10 is located around pull rod or shaft 12 and has an axis "A" as shown. In one embodiment of the invention, housing 10 is substantially tubular in shape and includes chamber 14. As illustrated, housing 10 is generally constructed with housing base 16 and housing cap 18. Threads 20 adjustably connect cap 18 and base 16 for the purpose described below.

Shaft guide 22 is substantially located within chamber 14 and includes axial passage 24 generally parallel to the axis of housing 10. Shaft 12 is positioned through axial passage 24 so that guide 22 controls the rotational and reciprocating movement of shaft 12 relative to axial passage 24. Seal 26, such as a stuffing box used in oilfield operations, is located between axial passage 24 and shaft 12 to prevent fluids within housing chamber 14 from being released into the environment. Bushing 28 and bushing 30 are located in the" annulus between axial passage 24 and shaft 12 to center shaft 12 within axial passage 24 and to prevent excesssive contact between shaft 12 and one part of seal 26.

Flange 32 is connected to guide 22, and bearing 34 is located between flange 32 and housing cap 18. As illustrated, bearing 34 has a spherical face 36 in contact with axial surface

38 of housing cap 18. Bearing 34 also has a substantially flat surface 40 in contact with the substantially flat surface 42 of flange 32.

Spring 44 is located within chamber 14 between housing 10 and flange 32 for urging flange 32 against bearing 34 so that bearing 34 is simultaneously urged against housing cap 18. As illustrated, one end of spring 44 is retained in recess 46 of housing base 16. The other end of spring 44 can directly contact flange surface 48, or bearing washer 50 can be positioned between spring 44 and flange surface 48. In operation, spring 44 is held in tension so that a positive force is urged against flange 32, and this force is simultaneously transmitted to bearing 30 and to housing cap 18.

Since the force exerted by spring 44 depends on variables such as the spring length, the spring constant, and the amount of compression initially loaded on spring 44, this force can be adjusted by rotating housing cap 18 relative to housing base 16 with threads 20. If housing cap 18 is rotated in a counterclockwise direction relative to housing base 16, and assuming standard cut threads, the force exerted by spring 44 will be reduced. If housing cap 18 is rotated in a clockwise direction relative to housing base 16, the force exerted by spring 44 will be increased. It will be apparent to those skilled in the art that other techniques can be used to adjust the force exerted by spring 44 against flange 32.

To retain a fluid within chamber 14, seal 52 can be located

5 bet een housing cap 18 and housing base IS, seal 54 can fee. located between housing axial surface 38 and bearing spherical surface 36, and seal 56 can be located between bearing flat surface 40 and flange flat surface 42. Other seals and seal arrangements can be configured to accomplish the desired sealing function. In one embodiment, fluid could be permitted into chamber 14 to facilitate lubrication of the elements or to provide pressure balancing capabilities.

As illustrated in Figure 1, axial surface 38 of housing cap 18 is preferably shaped to define a spherical surface having the same radius of spherical surface 36 of bearing 34. This shape would permit angular movement of shaft 12 and guide 22 about axis A by permitting bearing spherical surface 36 to move relative to housing axial surface 38 while maintaining contact therebetween. During this movement, spring 44 would slightly compress on one side, in the direction of the movement of shaft 12, and spring 44 would simultaneously elongate on the opposite side of spring 44. In this manner, spring 44 facilitates this angular movement of shaft 12 relative to housing 10 while maintaining a positive force against flange 32, bearing 34, and housing cap 18.

If the axial center of shaft 12 becomes misaligned with axis A, guide 22 and flange 32 will move transversely relative to axis A. During this transverse movement, bearing flat surface 40 can slide relative to flange surface 42, and flange surface 48 can slide relative to bearing washer 50. To facilitate

transverse and angular moveme-nt of shaft 12 relative to axis A, aperture 58 in housing cap 18 has a diameter larger than the diameter of guide 22.

Although spring 44 is drawn as a coil spring, it will be appreciated by those skilled in the art that different structures can be substituted without departing from the scope of the invention. For example, spring 44 could be designed as a hydraulic ram having a pressurized hydraulic fluid, or as a pneumatic device, or as another mechanism, to provide the force necessary to urge flange 32 against bearing 34 and housing cap 18. In addition, the coil spring illustrated as spring 44 could be constructed from different materials sufficient to provide strength, flexure, and dampening capability for the attenuation of vibrations. As used throughout this application, including the claims, the term "spring" is defined as any device, tool, or configuration that provides the functional capability described.

Other modifications and improvements can be made without departing from the scope of the invention. For example, housing axial surface 38 can be inclined at an angle other that an angle perpendicular to axis A. This embodiment would tend to retain bearing 34 in the same relative transverse position as guide 22 moves transversely in chamber 14. In addition, the orientation of the components, or order of the components, can be modified without departing from the scope of the invention. For example, axial surface 38 could be located on housing base 16 instead of housing cap 18, with a corresponding reorientation of the other elements, without affecting the operability of the invention. This embodiment of the invention would permit the bearing to support the weight of a heavy shaft, while the spring would operate from the opposite side to positively urge the flange toward the bearing. This embodiment is particularly useful in applications where there is a positive fluid pressure within the housing, and the spring force is designed to handle this fluid pressure without creating excessive frictional forces that might encumber the movement of the guide and flange relative to the housing.

In another embodiment, the connection between guide 22 and flange 32 could be flexible instead of rigid to permit angular movement of shaft 12 about axis A. Moreover, additional bearings could be included within the apparatus. For example, a bearing (not shown) could be engaged between spring 44 and housing base 16 to permit spring 44 to rotate angularly about axis A. This embodiment of the invention would be particularly suited for a Belleville spring. Alternatively, flange 32 could be located at a position away from guide 22 while still accomplishing the functional result disclosed by the invention.

It will be apparent to those skilled in the art that numerous modifications and improvements can be made to the embodiments illustrated and discussed herein without departing from the scope of the inventive concepts. The embodiments disclosed should be interpreted as illustrative examples of the invention and should not be construed to narrow the scope of the inventive concepts. 8

Claims

WHAT IS CLAIMED TS:

1. An apparatus for controlling the movement of a shaft, comprising: a housing having an axis through the interior space of said housing and having an axial face within the interior space of said housing; a guide located within said housing and having an axial passage for controlling the shaft in a direction substantially parallel to the axis of said housing, and wherein said guide permits reciprocation and rotation of the shaft within the axial passage through said guide; a flange connected to said guide in a plane substantially perpendicular to the axial passage through said guide; a bearing in contact between said flange and the axial face of said housing, wherein said bearing permits said flange to move within said housing in a direction substantially transverse to the axis of said housing, and wherein said bearing further permits said guide to move within said housing in an angular direction relative to the axis of said housing; and a spring engaged between said housing and said flange for urging said flange against said bearing and for permitting transverse and angular movement of said guide relative to the axis of said housing.

2. An apparatus as recited in Claim 1, wherein said spring is engaged between said housing and said guide for urging said flange against said bearing.

3. An apparatus as recited in Claim 1, further comprising a bearing washer between said spring and said flange.

4. An apparatus as recited in Claim 1, wherein said spring comprises a hydraulic ram for urging said flange against said bearing.

5. An apparatus as recited in Claim 1, wherein said spring comprises a coiled spring.

6. An apparatus as recited in Claim 1, further comprising a seal between the shaft and the axial passage of said guide.

7. An apparatus as recited in Claim 6, wherein the shaft comprises a pull rod and said seal comprises a stuffing box.

8. An apparatus as recited in Claim 1, wherein the axial face of said housing is beveled at an angle relative to the axis of said housing.

9. An apparatus as recited in Claim 1 wherein the axial face of said housing is spherical to permit angular movement of said guide relative to the axis of said housing.

10. An apparatus as recited in Claim 1, further comprising a seal between said bearing and the axial face of said housing.

11. An apparatus as recited in Claim 10, further comprising a seal between said flange and said bearing.

12. An apparatus as recited in Claim 1, wherein the force exerted by said spring against said flange is adjustable.

13. An apparatus as recited in Claim 1, wherein the surface of said flange in contact with said bearing is substantially perpendicular to the axis of said housing.

14. An apparatus as recited in Claim 1, wherein said flange is positioned away from said guide in an orientation substantially perpendicular to the axis through the interior space of said housing, and wherein said flange cooperates with said guide to permit movement of said guide transverse to the axis through said housing.