US2206488A - Water pump - Google Patents

Description

J. PAvLEcKA ET AL I July 2,. 1940.

WATER run Filed latch 13. 19:56

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3 3 mg NcZ r R war 0 v ig rd MA fi .vmM M p Patented July 2, 1940 UNITED STATES WATER PUMP John Pavlecka and Dana K. Badcrtscher, Dc-

troit, Mich, as'signors to Hudson Motor Car Company, Detroit, Michigan Mich, a corporation of Application March 13, 1938, Serial No. 68,654

Claims. (Cl. 103111) This invention relates to pumps, and particularly although not exclusively, to centrifugal water pumps employed for circulating the coolant of internal combustion engines. The invention 5 is especially applicable to water pumps of the type which is mounted on the same shaft asthe fan employed for drawing air through the radiator to remove heat from the coolant. One-of the principal objects of the invention is to provide new and improved means'for sealing the pump against leakage of the coolant and at the same time for absorbing and taking up end thrusts of the pump and fan assembly.

. Another object of this invention is to provide a novel thrust hearing within the pump, the bearing and associated parts being so arranged and constructed that any dirt from the coolant which might interfere with the hearing or the I sealing means is automatically thrown out by centrifugal force and washed away by the coolant.

Another object of this invention is to provide an improved thrust bearing and sealing means for a pump of the foregoing type which are relatively simple in construction, efiicient in operation to prevent leakage of the cooling liquid, and adapted to permit economies in the manufacture of the pump.-

Other objects of this invention will appear in the following description and appended claims,

reference being had to the accompanying drawing forming a. part of this specification wherein like reference characters designate corresponding parts in the several views.

Fig. 1 is a sectional view taken through the axis of the pump showing the parts in the positions taken by them when the pump and fan are turning fast enough for the fan to pull the pump shaft forwards. r

g Fig. 2 is a perspective view, with parts broken away, of the rear bearing, the rear bearing supporting boss, the rear end of the shaft, the pump impeller and the sealing means.

Fig. 3 is an enlargement ofthe portion of Fig.

'45 l enclosed in the small dotted square.

Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation, and it is not intended to limit the invention claimed herein beyond the requirements of the prior 5 art.

In the preferred form of the invention, shown in the drawing, there is provided a pump comprising a pump body I, a pump shaft 2 journalled in the body, a fan 3 and pulley l on the-front 10 end of the shaft, an impeller 5 on the rear end of the shaft, an impeller housing 6 enclosing the impeller, and an annular stationary shroud I having its rim held between the pump body and the impeller housing. The impeller 5 may be of 15 any suitable construction provided with impeller blades 55 for circulating the water or other coolant for the engine as indicated by the arrows in Fig. 1. r

The pump body I is a hollow casting arranged 20 to support a front bearing bushing I and a rear bearing bushing 9 in alinement with each other, one at each side of a grease chamber la in the casting. The rear bearing bushing 9 is mounted in a boss lb surrounded by an annular water 25 passage communicating with the inlet passage and having an annular outlet surrounding and parallel to the rear portion of the shaft.

The front end of the shaft is pressed into a. hub In which carries the fan .3 and pulley 4, 30 the back of the hub I 0 being flat and bearing against the front end of the front bearing bushing 8 to keep the shaft 2 from moving back. The rear end of the shaft'is pressed into the impeller 5, which carries a thrust washer ll bearing 35 against the rear end of the rear bearing bushing 9 to keep the shaft from moving forward.

The thrust washer II forms part of the sealing means, and an important feature of the invention resides in the arrangement of this 40 washer and the parts associated therewith. The front end 5a of the hub of the impeller 5 contains a deep counterbore concentric with and considerably larger ,in diameter than the shaft 2. The counterbore is composed of a short outer Y or forward cylindrical portion 5b separated from a deeper cylindrical inner or rear portion of smaller diameter by a circumferential groove or channel 5d. The inner or rear wall of the groove 51 lies in a plane perpendicular to the 50 shaft 2 so that it forms a flat annular shoulder is facingiforward towards the mouth of the counter-bore. The thrust washer H, which is small enough to pass into the large forward por tion 5b of the counterbore but too large to fit 55 into the smaller rear portion 5c of the counterbore, fits up against the shoulder 5e formed by the rear wall of the groove. Thus a force tending to move the shaft forward is transmitted through the shoulder 5e on the impeller to the rear face of the thrust washer II and from the front face of the thrust washer to the back end of the rear bearing bushing 9.

To insure that relative rotational movement occurs between the thrust washer II and the bearing bushing 9 instead of between the thrust washer and the impeller 5 which is not made of bearing metal and which is in contact with the washer over but a small annular area, the thrust washer is provided with a pair of radial lugs or cars Ila which fit loosely intoslots 5! cut in the walls of the counterbore in the front end of the impeller hub. These slots I! extend past the circumferential groove 5d against whose rear side the thrust washer rests so that the lugs I la on the thrust washer cannot bear on the ends of the slots 5f before the thrust washer II bears on the back wall 5e of the groove 5.

The rest of the sealing, means of which the thrust washer forms a part lies in back of the thrust washer l I in the inner part 50 of the counterbore in the impeller hub. It comprises a cork ring I2 which fits around the shaft 2 up against the back of the thrust washer I I, an annular coil spring I3 fitting in a groove around the cork ring I2 and which squeezes the ring onto the shaft 2,

a spiral spring I4 around the shaft between the f cork ring I! and the bottom of the counterbore which pushes or presses the cork ring I2 tightly against the thrust washer II,-and a thin metal washer I5 interposed between'the spiral spring I4 and the cork ring II which evenly distributes the pressure of the spiral spring over the back face of the cork ring. A snap ring II in the forward part 5b of the impeller hub recess extends across the slots 5) and holds the sealing means in the impeller hub counterbore during assembly of the pump.

When the pump is at rest, the spiral spring I4 within therecess inthe hub la of the impeller bearing bushing 9 by the spiral spring I4 so that the slight end play allowed the pump shaft assembly appears as clearance between the back of the thrust washer II and the rear face 5c of the annular groove in the. impeller hub counterbore, as shown in Figure 4. when. the pump is in operation, there is a certain speed at which the forward pull of the fan will equal the pressure of the spiral spring I4 within the impeller hub recess. Below that speed the parts will have the same axial position as when the pump is not operating. Above that speed the pump shaft assembly will move forward until the shoulder 5e,

formed by the rear wall of the annular groove in the impeller hub counterbore, bears against the thrust washer I I as shown in Figure 3 and the end play of the pump shaft assembly appears as clearance between the hub II of the fan and pulley and the front face of the front bearing bushingi,asshownin1"ig11re 1.

The slight end play of the pump shaft assembly mentioned above is necessary in order to allow for the different rates of thermal expansion of the pump shaft andthe pump body and the differences in expansion resulting from one heating up faster than the other after the engine is started. In pumps of this general type but without the groove 5d, the provision of the necessary l end play might occasionally cause trouble as follows: In a pump without the annular groove 5:! within the impeller hub counterbore, the thrust washer would rest against a shoulder joining the cylindrical walls of the two parts of the recess. When the pump and fan were at rest or operating slowly, dirt in the cooling water would get into the clearance between the thrust washerand the shoulder. When the pump and fan would be speeded up and the pull of the fan would move the pump shaft assembly forward the dirt would prevent the washer from seating squarely on the shoulder. A particle of dirt at one side would tip the washer so that one side of it would not a touch the end of the bearing bushing and water 'could easily leak out through the bearing. This I the bearing bushing requiring frequent replacements.

In accordance with the present invention, however, any dirt or particle of foreign matter lodging between the thrust washer II and the shoulder ie on the impeller hub is thrown out into the groove 5d and away from the shoulder 56 by centrifugal force as soon as the pump starts, as shown in Figure 4, and eventually escapes through one of the impeller hub slots Sj'into the main stream of coolant.

Thus,considered from one of its broader aspects, our invention contemplates providing improved sealing means for a paekless shaft subjected in operation to axial thrust, said means adapted both to seal such shaft against fluid leakage and to receive the axial thrust to which said shaft may be subjected. More particularly our invention contemplates providing improved sealing means for the shaft for a motor vehicle pump,

which, sealing means are adapted both to seal the shaft in the pump housing against leakage of the coolant and, in addition, to take up the end thrust or pull to which said shaft may be subject in operation, such as is the case when the fan is mounted on the pump shaft or when the pump impeller is of such a character that it exerts both radial and axial loads on the pump shaft. In addition, means are provided to collect and to dispose of the dirt and rust which the coolant may contain, thus eliminatngthe troubles which are caused by the presence of such impurities.

We claim:

1. In combination, a driven shaft having means exerting axial thrust thereon ir 1=.one direction at predetermined times, a fluid impeller having a hub secured to said shaft, said hub having a bore concentric with said shaft, a fixed bearing within which the shaft is journalled and having an end vertical abutment wall between the impeller and said means, a thrust washer received within the bore of the" hub movable axially on said shaft aaoasse ment wall in sealing engagement when the effort of said spring means exceeds said axial thrust, or

when such thrust is absent, thereby effecting axial movement of said annular abutment away from said washer, said hub having an annular trough of greater diameter than the bore of the hub and of greater width than the thickness of the thrustwasher facing the edge of said washer, said trough having an outlet into the-fluid stream for the discharge by centrifugal action of particles collecting in said trough.

2. In combination, a driven shaft having means exerting am'al thrust thereon in one direction at predetermined times, a fluid impeller having a hub secured to said shaft, a fixed bearing within which the shaft is journalled and having an end vertical abutment wall between the impeller and said means, a thrust member on said shaft received within the impeller hub and movable axially of the shaft relatively thereto; said hub having an abutment movable axially into engagement with one face of said thrust member, when said means exerts axial thrust on the shaft, to force said thrust member into sealing engagement with said abutment wall; and spring means for maintaining said thrust member in sealing engagement with said abutment wall when said axial thrust is removed or relieved to a predetermined extent, said hub having an annular trough with inward radial side walls facing the edge of said thrust member and an outlet into the fluid stream for the discharge by centrifugal action of particles collecting in said trough.

3. In combination, a driven shaft having means exerting axial thrust thereon in one direction at predetermined times, a fiuid impeller having a hub secured to said shaft, a fixed bearing within which the shaft is journalled and having an end vertical abutment wall between the impeller and said means, a thrust member on said shaft movable axially of the shaft relatively thereto; said hub having an abutment movable axially into engagement with one face of said thrust member,

when said means exerts axial thrust on the shaft, to force said thrust member into sealing engagement with said abutment wall; and spring means for maintaining said thrust member in sealing engagement with said abutment wall when said axial thrust is removed or relieved to a predetermined extent, said hub having an annular trough with inward radial side walls facing the 5 edge of said thrust member and an outlet into the fluid stream for the discharge by centrifugal action of particles collecting in said trough, said abutment of the hub forming one upright side wall of the trough. 30

4. In combination, a driven shaft movable axially at predetermined times by reason of end thrust, a fixed bearing for said shaft having a sealing wall, a fiuid impeller having a hub secured to the shaft, a sealing washer rotatably connected to the hub but movable axially relative thereto into sealing engagement with said sealing wall, said hub having a trough with inward radial side walls facing the edge of the washer and an outlet into the fluid stream for the discharge by $0 centrifugal action of particles collecting in said trough, one side wall of the trough forming an annular abutment movable axially into and out of engagement with the washer when end thrust in opposite directions is applied to the shaft.

5. In a water pump for an engine having a driven fan shaft subjected in operation to axial thrust, an impeller provided with a hub secured to the shaft, a fixed hearing within which-said shaft is journalled, a thrust member on said shaft 80 received within said impeller hub and rotatable therewith, said hub having axial movement relavtive to said member and a portion adapted to JOHN PAVLECKA. DANA K. BADERTSCHER.

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