US3474733A

US3474733A - Water pump and method of assembly

Info

Publication number: US3474733A
Application number: US672934A
Authority: US
Inventors: Jacob S Saletzki; Marvin C Keys
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1967-10-04
Filing date: 1967-10-04
Publication date: 1969-10-28
Anticipated expiration: 1986-10-28

Description

J. s. SALETZKI ETAL 3,47 ,7

IATER FUN? AND METHOD OF ASSEMBLY Filed Oct. 4, 1967 MARVIN c. xeYs.

' JACOB s. SALETZKI INVENTOR.

6511 124 2 M We 2,,

United States Patent U.S. Cl. 103103 1 Claim ABSTRACT OF THE DISCLOSURE A water pump having an impeller and drive gear axially displaced on a shaft which is journalled on bearings which are preloaded as a result of force exerted on the impeller by a spring which surrounds the shaft. The method of completely assembling the water pump and then inserting it intoits associated drive housing so that the pump can be installed in or removed from the drive housing as a unit.

This invention relates to a water pump and method of assembling same. In the past, the assembly of water pumps has been expensive, time-consuming, and not amenable to easy repair. Generally when a water pump is assembled or disassembled from its associated drive housing, the elements of the pump must be removed individually this results in a. time consuming efiiort and moreover, the elements of the pump are subject to being lost.

The present invention therefore has for one of its objects the new and improved method of assembling a water pump so that the pump can be entirely assembled prior to installation in the drive housing.

Another object of the present invention is the method of assembling a water pump so that it can be readily installed and removed from its drive housing while all of its parts remain in assembled relation.

Still another object of the present invention is the meth- 0d of assembling a water pump so that the bearings in which the impeller shaft rotates are preloaded prior to installation of the pump in its associated drive housing.

It is yet another object of the present invention to provide a method of asembling a water pump so that the entire pump including its drive gear are completely assembled and then located in the drive housing by means of a pilot extension of the water pump with all parts of the water pump remaining in proper position during the mating or demating of the water pump and the drive housing.

Yet another object of the present invention is to provide a method of assembling a water pump which will not structurally fail as a result of torsional vibration.

A further object of the present invention is a water pump which can be completely assembled prior to insertion in its drive housing.

A still further object of the present invention is a water pump which has bearings located intermediate the shaft and the water pump casing which are preloaded prior to assembly of the water pump and its drive housing.

Other objects and advantages of the present invention will be made obvious to those skilled in the art by the following description when considered in relation to the accompanying drawing of which;

A longitudinal sectional view of water pump of the present invention is shown in the single figure.

Referring now to the drawing the main casing of the water pump is shown gerenally at 10. Secured to one end of casing via means of seal 44 and suitable bolts is a cylindrical casing 46. Fastened t0 the end of casing 46 is an end plate 47. Mounted within the casing is an impeller 12, which is secured to shaft by furnace brazing. Previous designs have been limited in the amount of stress which the assembly could withstand. In the past, impellers have been secured to the shaft by means of tapers, shrink-fitting, etc. These prior art devices are more subject to failure than the instant invention, however, due to torsional vibration. Hence, the new and improved means of securing the impeller to the shaft has improved the durability of the pump. Impeller 12 has blades 16 which direct the water through outlet port 14. A low pressure area is shown generally at 18. Before the impeller 12 and shaft 20 are placed into casing 10, a seal 24 comprised of ceramic ring 22 and rubber carrier 26 is secured thereto. This design will place ceramic ring 22 in compression. The rubber carrier 26 could also be placed on the inner diameter of the ceramic ring 22, however, this has a tendency to cause the ceramic to crack when it expands. By placing the rubber on the outside, the ceramic seal 22 is in compression rather than tension, hence the ceramic will not crack. Another marked advantage of this seal arrangement is that carrier 26 and ring 22 can be easily serviced by removing the shft and impeller assembly and installing new parts. Because the ceramic seal is not distorted at assembly, no lapping after installation is required.

Main casing 10 has a flange 36 in which cup-like element 28 is press fitted with an inwardly projecting shoulder 38. Mounted within element 28 is a complementary ring shaped block 32 of carbon which has a highly polished surface engaging ceramic ring 22. Helical spring member 42 is mounted within molding 40 and forces carbon block 32 into sealing engagement with ceramic ring 22. Moulding 40 may be manufactured from a polymer, leather or other similar synthetic material. This entire sealing arrangement prevents water directed by the impeller from reaching shaft 20.

Main casing 10 has a pilot extension 50 into which casing 56 is press-fitted. Lip seal is secured in casing 56 and rides on shaft 20 in sealing engagement. Lip seal 80 prevents oil which is used to lubricate bearings 54 from passing into the impeller portion of the pump. Bearings 54 are also secured Within pilot extension 50 by means of retaining plate 58 and bolts 60 pressing on outer race 84 and longitudinal extension 86 of gear 62 pressing on the inner race 82. Driving gear 62 is secured to shaft 20 via means of key 64 and has teeth 66 which are driven by any suitable power source such as a power-take-olf of a driving engine.

Shaft 20 is also journalled in bearings 68 which are secured within drive housing 74. Bearings 68 are secured against gear 62 by means of lock washer 72 and lock nut 70. Main casing 10 is secured to drive housing 74 by means of bolts 91. Seal 52 is provided to provide adequate sealing of casing 10 and pilot extension 50. Drive housing 74 is provided with a face plate 88 which is secured to the engine block, power source, or other suitable power-take-off means by means of bolts 76. A cutout 78 in pilot extension 50 is also provided as an oil or water drainback. In the event oil passes by seal 80 or water passes by

seals

24, 22 and 32, the liquids will drain through the port 78 rather than intermix the oil and water.

The present invention permits ease of assembly. Moreover, this construction permits complete assembly of the water pump including preloading of bearing 54 prior to inserting it into drive housing 74. To assemble the pump, cup-like element 28 would be press-fitted into flange 36. Moulding 40 with spring 42 therein and carbon ring 32 would be inserted in cup-like element 28. Carbon ring 32 would then be inserted in cup-like element 28. A composite member comprising impeller 12, seal 24, and shaft 20 is then placed through spring 42 with ceramic ring 22 mated in sealing engagement with carbon ring 32. This arrangement allows the seal to be replaced without removing impeller 12 from the shaft. Casing 56 carrying seal 80is then press-fitted into sealing engagement" with shaft 20 and pilot extension 50. Bearing 54 is then secured against shoulder 90 of the shaft by means of retainer plate 58 and longitudinal extension 86 of gear 62. Gear 62 is keyed to the shaft and secured by lock nut 70 which holds the inner race of bearing 68 against gear 62. This entire completed assembly can then be installed in drive housing 70 and easily secured by means of bolts 91.

This method of assembly also facilitates pro-loading of bearing 54. This can be understood by reference to the drawing. Spring member 42 will tend to force carbon ring 32 against ceramic ring 22 which is a part of the impeller. Since impeller 12 is brazed to shaft 20, shaft 20 and gear 62 will tend to shift to the right as a result of the compression spring 42 tending to force impeller 12 to the right as shown in the drawings. The longitudinal extension 86 of gear 62 only exerts force against inner race 82 of bearing 54. Since outer .race 84 remains stationary and inner race 82 tends to move with the shaft, the bearing is in a preloaded condition. The bearing 68 is not preloaded and the outer race of bearing 68 slips freely into drive housing 74 with a slight exertion of force. With the drive housing and main casing united, the entire pump may then be mounted on a power source such as a power-take-otf of an engine by means of bolts 76 wherein teeth 66 would mesh with the teeth of the powertake-otf gearing. This would cause shaft 20 and hence impeller 12 to turn and pump Water from inlet port 48 through outlet port 14 as desired. Hence, a water pump and method of assembling same has been provided whereby the pump can be mounted on or removed from the drive housing as a unit while maintaining its bearings in a preloaded condition.

Since it is obvious that many changes and modifications can be made in the above described details without departing from the nature and spirit of the invention, it is to be understood that the invention is not limited to said details except as set forth in the appended claim.

We claim:

1. A water pump which can be completely assembled and integrally mounted as a unit in a drive housing comprising a main casing having a pilot extension extending radially therefrom, a cup-shaped element secured within said pilot extension, a first bearing mounted in said pilot extension, a shaft journalled in said first bearing, an impeller mounted on one end of said shaft having a ring seal integrally attached thereto, a first seal comprising a ring block of material mounted within said cup-shaped element, a spring surrounding said shaft and in compressive engagement with said ring block of material such that said ring block of material is placed in sealing engagement with said ring seal mounted on said impeller, a second seal mounted intermediate said first bearing and said cup-shaped element and in sealing engagement with said shaft, :1 gear secured to said shaft having a portion in contact with the inner race of said first bearing, a retainer plate secured to said pilot extension and in contact with the outer race of said first bearing, a second bearing axially displaced from said first bearing and in which said shaft is journalled, and locking means holding said second bearing in contact with said gear, said spring exerting force on said impeller, said shaft and said gear whereby said first bearing is preloaded prior to assembly of the water pump as a unit in a drive housing.

References Cited UNITED STATES PATENTS 1,47 6,781 12/ 1923 Vincent. 3,001,517 9/ 1961 Baker et a1. 3,071,075 1/1963 Spring. 3,272,129 9/1966 Leopold.

HENRY F. RADUAZO, Primary Examiner Us. or. X.R. 103-111; 230-133