US3273508A

US3273508A - Pumps

Info

Publication number: US3273508A
Application number: US426161A
Authority: US
Inventors: Kenneth R Lung
Original assignee: Tait Manufacturing Co
Current assignee: Tait Manufacturing Co
Priority date: 1965-01-18
Filing date: 1965-01-18
Publication date: 1966-09-20
Anticipated expiration: 1983-09-20

Description

Sept. 20, 1966 R. LUNG 3,273,508

PUMPS Filed Jan. 18, 1965 FIG-l FIG-3 so 4 m /2 f 4 A5 6 70 K 47 J ./a

x I m 84 lwmi 65' 64 W ea INVENTOR.

Y KENNETH R. LUNG ATTORNIEYS United States Patent 3,273,508 PUMPS Kenneth R. Lung, Morehead City, N.C., assignor to The Tait Manufacturing Company, Dayton, @hio, a corporation of Uhio Filed Jan. 18, 1965, Ser. No. 426,161 6 Claims. (Cl. 103-87) This invention relates to pumps, and more particularly, to an improved coupling assembly for connecting the shaft of the pump to the drive shaft extending from a motor which is coupled to the pump to form a combination unit.

The invention has special relation to a combination multi-stage centrifugal pump having a series of stacked pump housings which are connected rigidly to an elongated electric motor depending below. These motorpump combination units are adapted to be lowered into a well casing and submerged under the water level so that the water may flow into the inlet which is spaced at the lower end of the pump adjacent the top end of the motor. When servicing is required, however, the unit must be pulled from the casing so that the pump or motor can be worked upon. A problem of disassembling the unit may result from hardened mineral deposits such as lime forming on the pump components. Particularly, a deposit on the set screws which are commonly used to secure the coupling to the shafts of the pump and .motor renders it difficult to remove the screws for separating the shafts.

When the shaft extending from the motor is provided with an external spline formed along the upper end portion for uniformly distributing the drive torque, it is desirable to provide the lower end portion of the pump shaft with .a corresponding external spline so that the pump shaft and the motor shaft can be simply connected by a tubular coupling having a corresponding internal spline. However, it has been found that under certain operating conditions, the centrifugal impellers employed in the pump housings produce an upward axial thrust on the pump shaft, and in some installations, it has been found desirable to transfer this thrust to the motor shaft so that the thrust bearings provided within the motor can serve to carry the upward thrust as well as the normal downward thrust produced by the pump. For this reason, it is necessary to provide the spline coupling with some means to transfer the upward thrust, otherwise the pump shaft would be free to move axially within the spline coupling. In addition, it is desirable that this means be inexpensive and simple to assemble and disassemble even after an extended period of use, and furthermore, that it does not require rotational orientation between the shafts prior to assembly.

The present invention, therefore, is directed to an improved coupling assembly which employs a splined motor and pump shaft and which serves to transfer the axial thrust on the pump shaft to the motor shaft. In addition, the coupling of the invention provides for more convenient and simplified assembly and disassembly and is especially desirable when it is necessary to service the unit after an extended period of use.

Accordingly, it is a primary object of the present invention to provide an improved coupling assembly for a motor-pump combination unit which is adapted to use a motor shaft having an external spline formed on the end portion thereof, and in addition, serves to transfer axial thrust in either direction from the pump shaft to the motor shaft.

A further object of the present invention is to provide a submersible pump with an improved coupling assembly as outlined above, which is ideally suited for easy and quick assembly and disassembly and is especially adapted for convenient disconnection even after the unit ice has been used for several years and mineral deposits have formed around the coupling and shafts.

It is also an important object of the invention to provide a motor-pump unit with an improved coupling assembly which enables the pump shaft to be connected to the axially aligned motor shaft substantially independently of the rotational orientation between the shafts.

Still another object of the invention is to provide a submersible pump unit as outlined above with an improved coupling assembly wherein the torque produced by the motor is uniformly transferred to the pump shaft by a coupling having an internal spline portion which is in full circumferential engagement between end portions of the motor and pump shafts.

As a more specific object, the invention provides a motor-pump unit with an improved coupling assembly wherein the coupling can be retained on either the pump shaft or the motor shaft and conveniently disengaged from the other shaft depending on whether the motor or pump is to be serviced.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawing and the appended claims.

In the drawing FIG. 1 is an elevational view illustrating a submersible motor-pump unit incorporating an improved coupling assembly formed in accordance with the invention;

FIG. 2 is an enlarged fragmentary view in axial section through the motor portion of the submersible motorpump unit;

FIG. 3 is an enlarged fragmentary view in axial section through the pump portion of the unit shown in FIG. 1;

FIG. 4 is an enlarged radial section as viewed along the line 4-4 of FIG. 3;

FIG. 5 is an enlarged radial section as viewed along the line 5-5 of FIG. 3; and

FIG. 6 is an exploded elevational view of the coupling assembly shown in FIG. 3.

Referring to the drawing, which illustrates a typical application and a preferred embodiment of the present invention, the submersible motor-pump combination unit shown in FIG. 1 and generally referred to as 10 includes a multi-stage centrifugal pump 12, a motor 14 having leads 15 extending therefrom, and an intake housing 16 which serves to connect the pump 12 rigidly to the motor 14. A cylindrical screen 18 is mounted around the intake housing 16 and serves to filter the water flowing into the bottom of the pump 12. A shield 19 is mounted on the side of the pump 12 and serves to protect the motor leads 15.

Referring to the detailed view of FIG. 2, the motor 14 generally includes a motor shaft 20 and rotor 22 which are rotatably mounted within the sleeve bearings 24 pressed Within the end brackets 26 and '27. The motor casing 30 serves to support the

end brackets

26 and 27 and also the stator 31 which is mounted within a cylindrical yoke 33. A thrust bearing 35 is mounted on the motor shaft 20 at each end of the rotor 22 and is adapted to rotate with the motor shaft against the ends of the sleeve bearings 24 for opposing axial thrust in either direction, which is transferred to the motor shaft 21 from the pump 12.

Referring to FIG. 3, the intake housing includes an annular bottom rn'oun-ting flange 40 which is rigidly secured to the top end bracket 27 of the motor 14 by a series of screws '42. The upper end of the intake housing 16 includes a threaded portion 43 which connects with an outer pump shell 45 enclosing a plastic pump casing 46. A series of open sections 4 7 are provided in the lower portion of the intake housing 16 to allow water to fiow through the screen 18 and enter the inlet portion 48 of the lowermost centrifugal impeller 50 which is rigidly mounted on a pump shaft 52 by a suitable fastening means (not shown). Included as part of the intake housing 16 is a cylindrical bearing retaining hub 55 which is centrally spaced by a series of three ribs 57. The spaces between the ribs 57 connect with the open sections 47 to direct the flow of water upwardly past the hub 55 to the impeller 50. Mounted within the hub 55 is a sleeve-type bearing 59 for rotatably supporting the pump shaft 52.

The upper end portion of the motor shaft 20 is provided with an external spline 62 ('FIG. 6) and a cylindrical groove 64 spaced from the end of the motor shaft 20 to provide a spline portion 65 spaced above the groove 64. A'butting the top end of the mot-or shaft 20 (FIG. 3) is the lower end of the pump shaft 52, which is also provided with an external spline 68 corresponding in configuration and in size to the spline 62 formed on the motor shaft 20. Preferably, the spline 68 on the pump shaft 52 extends upwardly on the shaft 52 by a distance slightly greater than the axial length of the cylindrical tubular coupling 7 0.

The coupling 70 is provided with an internal spline 72 (FIG. 4) which conforms or corresponds to the

splines

62 and 68 and thereby provides a positive drive connection between the motor shaft 20 and the pump shaft 52. As a result of the extended spline 68, it can be seen that the coupling 70 can be moved upwardly on the pump shaft 52 until it disengages the spline portion 65 of the motor shaft 20. The extended spline 68 is desirable to permit convenient uncoupling of the pump shaft 52 from the motor shaft 20 without separating the pump 12 from the motor 14. This feature is desirable for simplifying servicing, as for example, when it is desirable to operate or test the motor 20 without operating the pump 12.

The lower end portion of the pump shaft 52 is provided with a circumferential groove 75 which preferably is spaced from the bottom end of the pump shaft 52 to provide a spline portion 77 having an axial length substantially the same as the spline portion 65 on the motor shaft 20.

Formed within the wall of the tubular coupling '70, as shown in FIG. 5, are a pair of radially extending slots 80 which are spaced apart axially a distance equal to or slightly greater than the combined axial distance between the

grooves

64 and 75 and the ends of their respective shafts so that the slots 80 are radially aligned with the

grooves

64 and 75 when the coupling and shafts are assembled in abutting relationship (FIG. 3). As shown in FIG. 5, the slots 80 formed in the coupling 70 result in diametrically opposed coupling segments 82 which serve to connect the end portions 84 of the coupling 70 with the central portion 85. As mentioned above, the intermediate or central portion 85 of the coupling provides full circumferential engagement with the

spline portions

65 and 77. Thus the torque transferred from the motor shaft 20 to the pump shaft 52 is uniformly distributed around the entire periphery of the

spline portions

65 and 77. This eliminates the necessity for the coupling segments 82 to carry the full torque, which is especially desirable when the coupling is formed from a plastic material.

Inserted within each of the slots 80 is a hat U-shaped spring type retaining clip 90 which is adapted to extend past the coupling segments 82 and includes a gripping head portion 92 extending radially outwardly from the exterior surface of the coupling 70. As shown in FIG. 5, the curved legs 95 of the retaining clips 90 are each provided with a curved inner edge 96 which conforms to the inner diameter of the grooves 64 and '75 so that the legs 95 snap into a firm seating engagement within the grooves. Thus, in effect, each of the

grooves

64 and 75 provides corresponding diametrically opposed slots for receiving the legs 95 of the retaining clips 90.

As can be seen from FIG. 3, the retaining clips 90, which have a thickness slightly less than the axial length of the slots, serve to prevent the coupling 70 from moving axially on either the pump shaft 52 or the motor shaft 20.

In addition, the retaining clips 90 serve to transfer the upward axial thrust produced, under some flow and pressure operating conditions, on the pump shaft 52 to the motor shaft 20 so that the thrust can be opposed by the motor thrust bearings 35. In normal operation, however, the impellers 50 produce a downward thrust on the pump shaft 52. which is transferred to the motor shaft 20 as a result of the abutting ends of the shafts.

As shown in FIG. 5, the gripping head portion 92 of each of the clips 90 is provided with a hole 97 which facilitates easy removal of the clips 90 by the use of a tool, as for example, a wire having a hook formed on one end. Also, the extending portion 92 may be easily gripped by suitable pliers to simplify the assembly or removal of the clips 90. This easy removal of the clips 90 has been found to be especially desirable after the pump has been in use for an extended period of time and mineral deposits have formed on the coupling 70.

One primary advantage of the improved coupling assembly according to the invention is that it does not require precise orientation of the pump shaft 52 with the motor shaft 20. This results from the fact that the coupling 70 can engage the pump shaft 52 and motor shaft 20 at any point where the spline portions are aligned. Furthermore, since the grooves '64 and are circumferential, the retaining clips can be inserted independently of the angular position or orientation of the shafts.

While the two retaining clips 90 could be formed as one integral part, it is preferred that they be formed separately so that either clip may be removed whereby the coupling 70 will remain on either the pump or motor shaft. For example, when it is necessary to remove the motor 14- for servicing, the bottom clip 90 is withdrawn so that the coupling will remain with the pump shaft 52.

From the drawing and the above description, it can be seen that the improved coupling assembly according to the invention provides several distinct advantages and features. Specifically, the trust transferring coupling enables the use of a motor having a splined shaft which has been found desirable for uniformly transferring the torque from the motor shaft to the pump shaft. As another feature, the coupling is easy to disassemble and reassemble during servicing even after an extended period of use where lime or other deposits have formed on the coupling and shafts. Also, the motor and pump shafts can be quickly connected substantially independently of the relative rotational orientation of the shafts, and in addition, the coupling 70 is provided with a center section which circumferentially engages the end portions of each shaft so that the torque is transferred uniformly through the splined engagement.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A pump unit comprising a motor including a projecting motor shaft having spline means formed externally on the end portion thereof, a pump housing rigidly connected to the end of said motor, a pump shaft rotatably supported within said housing, spline means formed externally on the end portion of said pump shaft, a tubular coupling having corresponding internal spline means engaging the end portion of said motor shaft and the adjacent end portion of said pump shaft to provide a positive drive connection therebetween, means defining diametrically opposed grooves in said end portion of each said shaft spaced a predetermined distance from the end thereof, means defining diametrically opposed slots in said coupling opposite each said groove and spaced apart axially to provide full circumferential driving engagement between the central portion of said coupling and the end portions of said shafts, and retaining clip means removably inserted in said slots for engaging said corresponding grooves to limit relative axial movement between said coupling and said shafts.

2. A pump unit comprising a motor including a projecting motor shaft having spline means formed externally on the end portion thereof, a pump housing rigidly connected to the end of said motor, a pump shaft rotatably supported within said housing, spline means formed externally on the end portion of said pump shaft, a tubular coupling having corresponding internal spline means engaging the end portion of said motor shaft and the adjacent end portion of said pump shaft to provide a positive drive connection therebetween, means defining a circumferential groove in said end portion of each said shaft spaced a predetermined distance from the end thereof, means defining a radially extending slot in said coupling opposite each said groove and spaced apart axially to provide full circumferential driving engagement between the central portion of said coupling and the end portions of said shafts, and spring type retaining clip means removably inserted in each of said slots for engaging said corresponding groove independently of the rotational orientation of said shafts to limit axial movement of said coupling on said shafts.

3. A pump unit comprising a motor including a projecting motor shaft having a spline formed externally on the end portion thereof, thrust bearing means mounted within said motors, a pump housing rigidly connected to the end of said motor, at least one impeller mounted on a pump shaft rotatably supported within said housing, a spline formed externally on the end portion of said pump shaft, a tubular coupling having a corresponding internal spline engaging the end portion of said motor shaft and the adjacent end portion of said pump shaft to provide a positive drive connection therebetween, means defining a circumferential groove formed in said end portion of each said shaft and spaced a predetermined distance from the end thereof, means defining a pair of diametrically opposed slots in said coupling opposite each said groove and spaced apart axially to provide full circumferential driving engagement between the central portion of said coupling and the end portions of said shafts, and a generally fiat U-shaped retaining clip removably inserted in each of said slots for engaging said corresponding grooves independently of the rotational orientation of said shafts to limit axial movement of said coupling on said shafts and to provide for the transfer of axial thrust from said pump shaft to said thrust bearing means within said motor.

4. A submersible multistage pump unit comprising a motor having a casing adapted to be installed in a vertical position within a well casing and including an upwardly projecting motor shaft having spline means formed externally on the upper end portion thereof, a multistage pump housing rigidly connected to the top end of said motor casing, at least one centrifugal impeller mounted on a pump shaft rotatably supported within said housing, spline means formed externally on the lower end portion of said pump shaft, a coupling having internal spline means and engaging the upper end portion of said motor shaft and the lower end portion of said pump shaft to provide a positive drive connection therebetween, means defining circumferential groove means formed in said end portions of each said shaft and spaced at predetermined distance from the end thereof, means defining a radially extending slot in said coupling opposite each said groove means and spaced apart axially to provide a full circumferential driving engagement between the central portion of said coupling and the end portions of said shafts, and retaining clip means removably inserted in each of said slot means for engaging said groove means to limit axial movement of said coupling on said shafts and to transfer axial thrust from said pump shaft to said motor shaft.

5. A submersible multistage pump unit comprising a motor having a casing adapted to be installed in a vertical position within a well casing and including an upwardly projecting motor shaft having spline means formed externally on the upper end portion thereof, a multistage pump housing rigidly connected to the top end of said motor casing, at least one centrifugal impeller mounted on a pump shaft rotatably supported within said housing, spline means formed externally on the lower end portion of said pump shaft, a tubular coupling having corresponding internal spline means for engaging the upper end portion of said motor shaft and the lower end portion of said pump shaft to provide a positive drive connection therebetween, means defining a circumferential groove formed in said end portion of each said shafts and spaced a predetermined distance from the end thereof, means defining a radially extending slot in said coupling opposite each said groove and spaced apart axially to provide full circumferential driving engagement between the central portion of said coupling and the end portions of said shafts, and a generally U-shaped retaining clip removably inserted in each of said slots for engaging said corresponding groove independently of the rotational orientation of said shafts to limit axial movement of said coupling on said shafts and to transfer axial thrust from said pump shaft to said motor shaft.

6. A submersible multistage pump unit comprising a motor having a casing adapted to be installed in a vertical position within a well casing and including an upwardly projecting motor shaft having a spline formed externally on the upper end portion thereof, thrust bearing means within said motor, a multistage pump housing rigidly connected to the top end of said motor casing, a pump shaft rotatably supported within said housing, a spline formed externally on the lower end portion of said pump shaft, a cylindrical coupling having a corresponding internal spline and engaging the upper end portion of said motor shaft and the lower end portion of said pump shaft to provide a positive drive connection therebetween, circumferential groove means in said end portion of each said shafts and spaced a predetermined distance from the end thereof, means defining a pair of diametrically opposed slots in said coupling opposite each said groove and spaced apart axially to provide full circumferential driving engagement between the central portion of said coupling and the end portions of said shafts, and a generally flat spring type retaining clip removably inserted in each said pair of slots for engaging each said groove independently of the rotational orientation of said shafts to limit axial movement of said coupling on said shafts and to transfer axial thrust from said pump shaft to said thrust bearing means within said motor.

References Cited by the Examiner UNITED STATES PATENTS 502,686 8/1893 Tilton 287-108 2,851,956 9/1958 Lung -a 103--108 X FOREIGN PATENTS 668,607 3/1952 Great Britain.

ROBERT M. WALKER, Primary Examiner.

Claims

1. A PUMP UNIT COMPRISING A MOTOR INCLUDING A PROJECTING MOTOR SHAFT HAVING SPLINE MEANS FORMED EXTERNALLY ON THE END PORTION THEREOF, A PUMP HOUSING RIGIDLY CONNECTED TO THE END OF SAID MOTOR, A PUMP SHAFT ROTATABLY SUPPORTED WITHIN SAID HOUSING, SPLINE MEANS FORMED EXTERNALLY ON THE END PORTION OF SAID PUMP, SHAFT, A TUBULAR COUPLING HAVING A CORRESPONDING INTERNAL SPLINE MEANS ENGAGING THE END PORTION OF SAID MOTOR SHAFT AND THE ADJACENT END PORTION OF SAID PUMP SHAFT TO PROVIDE A POSITIVE DRIVE CONNECTION THEREBETWEEN, MEANS DEFINING DIAMETRICALLY OPPOSED GROOVES IN SAID END PORTION OF EACH SAID SHAFT SPACED A PREDETERMINED DISTANCE FROM THE END THEREOF, MEANS DEFINING DIAMETRICALLY OPPOSED SLOTS IN SAID COUPLING OPPOSITE EACH SAID GROOVE AND SPACED APART AXIALLY TO PROVIDE FULL CIRCUMFERENTIALLY DRIVING ENGAGEMENT BETWEEN THE CENTRAL PORTION OF SAID COUPLING AND THE END PORTIONS OF SAID SHAFTS, AND RETAINING CLIP MEANS REMOVABLY INSERTED IN SAID SLOTS FOR ENGAGING SAID CORRESPONDING COUPLING AND SAID SHAFTS.