US 2957459 A
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Description (OCR text may contain errors)
Oct. 25, 1960 M. J. TAUSCHEK 2,957,459
HYDRAULIC FAN DRIVE Filed Dec. 12, 1958 2 Sheets-Sheet 1 Oct. 25, 1960 Filed Dec. 12, 1958 Fig.4
M. J. TAUSCHEK HYDRAULIC FAN DRIVE 2 Sheets-Sheet 2 ouurw 517K775 atent r 2,957,459 Patented Oct. 25, 1960 HYDRAULIC FAN DRIVE .vlax J. Tauschek, Lyndhnrst, Ohio, assignor to Thompson Ramo Wooldridge Inc., Cleveland, Ohio, at corporation of Ohio Filed Dec. 12, 1958, Ser. No. 779,883
8 Claims. (Cl. 123-4112) This invention relates to an improvement in fan drives and more particularly to a fan which is directly operated by kinetic energy from a pump in the coolant circulation system of an automotive engine or the like.
Heretofore various types of fan drive systems have been provided for controlling the actuation of the fan in accordance with temperature conditions in the engine. However, these fans have generally been of a type in which a clutch has either engaged or disengaged the fan from drive means therefor in accordance with a predetermined temperature condition. Consequently, there has been a loss of cooling action except when the predetermined temperature condition has obtained, and further there has been no temperature control of the action of the fan after it has been engaged. Although some types of fans have provided for control in accordance with the temperature condition of the water in the circulating system, these fans have been ineffective for the reason that the pumping system has been widely separated from the fan and has led to a loss in efliciency and to inaccurate control.
The present invention provides a fan drive system wherein a thermostatic coolant control flow valve of the conventional type is positioned in the circulation system of the engine and is adapted to control the temperature in the engine as well as the action of the fan. In accordance with this invention, the fan is driven by a turbine wheel which is disposed in a housing for the pump of the cooling system. The turbine wheel is driven by kinetic energy developed in the coolant as it passes from the pump and before entering the volute of the pump. The remaining energy in the coolant is utilized in transmitting the coolant through the coolant circulating systern of the engine. This kinetic energy imparted to the coolant by the pump impeller is directly used to drive the fan and the remaining energy in the coolant is then converted to a pressure head in the pump volute for flowing the coolant through the engine and radiator. Under some circumstances, the pressure head derived from the pump impeller is also used to drive the turbine. In a typical centrifugal pump, approximately half the pressure rise occurs in the volute surrounding the pump by conversion of the kinetic energy of the fluid leaving the pump into pressure head. In the present fan drive, substantially all the kinetic energy at the impeller exit is available to drive the turbine directly. In addition, part of the pressure head can be used if the turbine passages are proportioned so that a partial reaction turbine rather than a simple impulse turbine is formed (i.e., by making the exit area of the turbine vanes less than the entrance area thereof.)
An important feature of the invention is the dual use of a single thermosensitive valve for controlling fan drive as well as coolant flow. An additional important feature is the provision of a hydro-kinetic fan drive in which the water pump and impeller perform the dual function of pumping coolant and providing a power source for the hydro-kinetic drive.
In one embodiment of the invention, by-pass means are provided so that the fan drive may be moderated when the thermostatic valve is quickly opened or closed.
Accordingly, it is an object of the present invention to provide a fan drive for automatic vehicles or the like in which the pump for the cooling system of the engine drives a fan directly with kinetic energy imparted to the coolant before the energy is converted to a pressure head for circulating the coolant through the cooling system.
Another object of the invention is to provide a fan drive system wherein a single temperature responsive valve is used as heretofore provided in the cooling system for the engine and also to control the operation of the fan.
Another object of the invention is to provide an embodiment of a fan drive system in which a by-pass is adapted to moderate sharp changes in the fan drive rate when the thermostatic control valve is opened.
Other objects and features of the invention will become apparent as the description proceeds in accordance with the drawings in which:
Figure 1 is a schematic representation of a fan drive unit in association with an engine for an automotive vehicle or the like;
Figure 2 is a schematic representation of another embodiment of the invention;
Figure 3 is a back or rear view of a coolant pump and fan drive unit according to the invention; and
Figure 4 is a vertical sectional view of the coolant pump and fan drive unit according to the invention.
Referring now to the drawings, the invention comprises a combination pump and fan drive 10 positioned on the engine block of a liquid cooled internal combustion engine 12 and communicating with the fluid circulation system for the engine by means of a passage 14 leading from the top of the engine to a radiator 16, and a passage 13 leading from the radiator to the unit 10. A further conduit 20 leads from the unit 10 to the coolant intake of the engine 12. It will be understood that the unit 10 could also be constructed so that coolant would be pumped from the engine to the radiator.
As seen in Figure 4, the unit 10 comprises a fan 24 connected to a turbine wheel 26 by a shaft 28, a centrifugal impeller 39 connected to a pulley 32 by a hollow shaft 34 in which the shaft 28 is journaled and a housing 36 enclosing the turbine wheel 26 and the impeller 30 so that the kinetic energy 'of the coolant from the impeller drives the turbine wheel prior to entry of the fluid into the annular volute or collecting chamber 38 defined by the housing.
A flange bearing 40' is secured in the inner end of the shaft 34 so as to bear against the hub 42 of the turbine wheel 26 and a flange bearing 44 is secured in the outer end of the shaft 34 and may afford a bearing surface for a fan mounting hub 45 to which blades 46 are aflixed by bolts 47. Thus, the turbine wheel 26 is maintained in proper axial alignment relative to the hollow shaft 34 by the hubs 42 and 45 and their relation to the flanges on the bearings 40 and 44 which serve as axial thrust bearings. The shaft 34 is journaled in a combined radial and thrust ball bearing assembly 48 provided with a split retainer ring 49 retained in the hub 50 of the housing so as to fix the outer race of the bearing in position. The halls of the bearing 48 ride in grooves around the shaft 34. and this shaft is thus mounted for free rotation but is held against axial shifting relative to the housing 36.
The housing 36 provides a header portion or inlet eye 52 having a recess with an annular shoulder 54 receiving thereagainst a sealing means 56 for preventing the passage of fluid through the bearing assembly 48 and comprising an annular cup-shaped retaining bracket 58, a sealing element 60 having a shoulder 62, a helical spring 64 hearing against the shoulder 62 and a sealing element 66 riding on the hub 68 of the impeller 30.
A second sealing means 70 is sealed in a recess 72 in the back face of the impeller 30 around the hub 42 of the turbine wheel 26. The seal 70 includes cup 74 coacting with an O-ring 78 to stop leakage from the pump to the bearing 40.
The housing 36 as a back plate 80 secured thereto by bolts 82 and an annular gasket 84 is disposed between the wall plate and the housing. The housing 36 may be secured to the engine block of the engine 12 or to support structure on the engine block (not shown) in accordance with the understanding of those skilled in the art, it being understood that Figures 1 and 2 are schematic showings of the relationship between the fan drive unit and the engine and radiator. In the embodiment of the housing shown in Figures 3 and 4, an inlet conduit 86 joined with the eye 52 and an outlet conduit 88 joined with the volute 38 are formed integrally with the housing structure and may be secured to suitable support structure and related portions of the cooling system such as passages 18 and respectively, by means of bolts (not shown) received in apertures 90 and 92 defined in the flared ends of the conduits 86 and 88.
The vanes 96 of the turbine wheel 26 immediately surround vanes 98 of the centrifugal impeller and in turn are surrounded by the collecting chamber 38. By this arrangement kinetic energy of fluid discharged centrifugally from the impeller is used directly for driving the turbine wheel 26, as stated, and there is no energy loss such as is produced when the kinetic energy from the pump is first coverted to a pressure head and then reconverted to mechanical energy. However, where fan powder requirements are large, the kinetic energy plus part of the pressure head may be used to drive the turbine, as hereinbefore described. In order to control both the fan drive and the engine temperature simultaneously, a conventional thermostatic control valve 100 is disposed in the passage 14 leading from the engine 12 to the radiator 16.
The pump impeller 30 may be driven from the pulley 32 by a suitable belt means such as indicated at 102 in Figure l, which in turn is entrained on a pulley 104 on the crankshaft 106. The pump to crankshaft speed ratio may be, for example, 1.4 to 1, although it will be appreciated that the pulley 32 may be driven by other means within the scope of the invention. The pump to crankshaft speed ratio is determined by the energy required to drive the fan and is raised sufficiently over that ordinarily used so that suflicient kinetic energy is available in the coolant. However, because the fan drive is from the coolant and not from the crankshaft, no additional energy is taken from the crankshaft.
At relatively low engine temperatures, circulation of fluid through the cooling system will be prevented by the thermostatic control valve 100 and the fan 24 will be in inoperative condition. However, in response to a predetermined temperature increase, the valve 100 will open and the fan 24 will be driven at a controlled rate relative to engine speed rate as determined by the coolant flow which is regulated by the valve.
In order to moderate sharp increases in fan speed at such time, a by-pass system may be provided such as is shown schematically in Figure 2 wherein similar reference numerals designate similar parts. In this embodi ment, a bypass conduit 108 joins the passage 14 upstream from the valve 100 with the pump inlet of the unit 10. Preferably an orifice restriction 110 limits the flow through the by-pass 108 to between 10% to 25% of total flow in the coolant system, and 20% of total flow has been found to be a suitable ratio. Therefore, the turbine wheel 26 is responsive both to fluid from the radiator 16 as controlled by the valve 100, and also to flow from the by-pass 108. Thus the fan 24 can be driven even when the valve is closed, thereby elimi-,
nating abrupt changes in fan speed when the valve is opened and also assuring a suitable low rate of fan operation when the valve is closed and temperatures in the system are relatively low.
A further advantage is afforded by a by-pass arrangement in that a certain amount of air circulation around the motor will be produced during warm up of the engine without driving the fan at high speeds to pull in outside air. The amount of by-pass fluid can be calibrated in relationship to the pump to crankshaft ratio and the characteristics of the control valve 100 to afford the highest efliciency of fan operation while avoiding unnecessary loads on the engine.
It will be understood that the by-pass operation may be effected in yet other ways within the scope of the invention, and that the construction of the housing for the fan drive unit may be varied accordingly. However, in each instance the turbine wheel will be interposed between the centrifugal impeller and the collecting chamber 38 so as to afford the desired direct conversion of kinetic energy from the pump to mechanical energy in the turbine wheel. A by-pass is ordinarily used in an automotive cooling system in order that part of the coolant may be continuously recirculated through the engine block, thereby avoiding stagnation when the thermostat is closed and there is no flow through the external cooling system. A by-pass can also be made to function as described if it is wished to have by-pass flow through the engine block and not have this fiow affect the operation of the fan drive by taking the bypass flow from between the impeller and the turbine. Consequently the by-pass can be used in three ways: to moderate fan drive operation without recirculating coolant; to recirculate coolant without effecting fan drive operation; and to perform the first two functions simultaneously.
Although I have herein set forth and described my invention with respect to certain specific principles and details thereof, these may be varied without departing from the spirit and scope of the invention, as set forth in the hereunto appended claims.
I claim as my invention:
1. A fluid drive comprising a pump having a fluid inlet, a centrifugal impeller receiving fluid from the inlet, a turbine wheel having vanes receiving fluid directly from the impeller to drive the wheel by kinetic energy imparted thereto by the impeller, a collecting chamber surrounding the turbine vanes receiving the fluid therefrom for converting the kinetic energy thereof into a pressure head, means driven by said turbine wheel, and thermosensitive means controlling fiow of fluid to control rate of flow of said pump and drive input to said turbine driven means.
2. In combination with a fluid flow circuit, thermosensitive means at one point in said circuit controlling flow of fluid through said circuit, a pump at a second point in said circuit having a fluid inlet, a centrifugal impeller receiving fluid from the inlet, a turbine wheel having vanes receiving fluid directly from the impeller to drive the wheel by kinetic energy imparted thereto by the impeller, a collecting chamber surrounding the turbine vanes receiving the fluid therefrom for converting the kinetic energy thereof into a pressure head, and means driven by said turbine wheel, the rate of flow through said pump and the mechanical energy of said turbine wheel being determined by said thermosensitive means.
3. In combination with a water cooled engine, a radiator and a passage connecting said engine and said radiator, a fan drive unit comprising a pump housing defining a collecting chamber and inlet and outlet means, a centrifugal impeller journalled in said housing, a turbine wheel journalled in said housing between said impeller and said collecting chamber for receiving kinetic energy directly from said impeller, a passage connecting said radiator with the inlet of said housing, said outlet of said housing communicating with the cooling system in said engine, a fan fixedly connected with said turbine wheel and thermosensitive control means in the cooling system of said engine opening in response to temperature increases to admit fluid through said passage connecting said engine and said radiator and said passage connecting said radiator and said inlet of said housing to energize said fan and control the temperature of said engine.
4. In combination with a radiator, an engine and a coolant flow circuit connecting the radiator and the engine, a fan drive assembly comprising a fan, a turbine wheel supporting said fan, a housing on said engine rotatably receiving said turbine wheel and defining a collecting chamber and inlet and outlet means connected in said circuit, a pump impeller journalled in said housing in position to drive said turbine wheel directly by kinetic energy therefrom prior to said collecting chamber, a thermostatic control valve in said circuit opening in response to temperature increases to admit fluid to said pump impeller and by pass means in said circuit cornmunicating with said housing and moderating torque on said turbine when said control valve is initially opened in response to temperature increases in said engine.
5. A fan drive unit comprising a housing defining a collecting ring chamber, an inlet and an outlet, a hollow shaft journalled in said housing, a centrifugal impeller in said housing fixedly secured to said hollow shaft, a pulley outside said housing fixedly secured to said hollow shaft, a turbine wheel in said housing fixedly secured to an inner end of said fan shaft and a fan fixedly secured to an outer end of said fan shaft, said turbine wheel having vanes surrounding said impeller, said collecting ring chamber surrounding said turbine wheel whereby kinetic energy from said impeller is utilized directly in driving said turbine.
6. In combination with a radiator, an engine and a coolant flow circuit connecting the radiator and the engine, a drive assembly comprising a turbine wheel, a housing on said engine rotatably receiving said turbine wheel and defining a collecting chamber and inlet and outlet means connected in said circuit, a centrifugal impeller journalled in said housing in position to drive said turbine wheel prior to said collecting chamber by kinetic energy from said impeller, a thermostatic control valve in said circuit for controlling the flow of fluid to said impeller and means driven by said turbine wheel at a rate controlled by said thermostatic control valve.
7. In combination with a radiator, an engine and a coolant flow circuit connecting the radiator and the engine, a fan drive assembly comprising a fan, a turbine wheel connected to said fan in driving relationship thereto, a housing on said engine rotatably receiving said turbine wheel and defining a collecting chamber inlet and outlet means connected in said circuit, a pump impeller journalled in said housing in position to drive said turbine wheel by kinetic energy therefrom prior to said collecting chamber, a thermostatic control valve in said circuit for controlling the flow of fluid through said circuit to said pump and bypass means in said circuit communicating with said pump and moderating torque on said turbine wheel, said control valve being initially opened in response to temperature increases in said engine.
8. In combination with a water cooled engine, a radiator and a passage connecting said engine and said radiator, a fan drive unit comprising a pump housing defining a collecting chamber and inlet and outlet means, said pump housing being secured to said engine in position for said outlet to communicate with the engine block cooling system for said engine, a pump impeller journalled in said housing, a turbine wheel journalled in said housing between said pump impeller and said collecting chamber, a passage connecting said radiator with the inlet of said housing, a fan fixedly connected with said turbine wheel, a bypass passage leading from said pas sage connecting said engine and said radiator to said pump housing and a thermostatic control in the cooling system of said engine for simultaneously controlling the rate of operation of said fan and the temperature of said engine, said by pass being disposed between said thermostatic control and said engine.
References Cited in the file of this patent UNITED STATES PATENTS 1,256,709 Ludeman Feb. 19, 1918 2,349,731 Hornschuch May 23, 1944 FOREIGN PATENTS 195,284 Great Britain Mar. 29, 1923 883,378 Germany July 16, 1953 922,394 Germany Jan. 13, 1955