US2678031A - Radiator fan and coolant impeller speed control mechanism - Google Patents

Description

y 11, 1954 c. B. sPAsE ETAL 2,678,031

RADIATOR FAN AND COOLANT IMPELLER SPEED CONTROL MECHANISM Filed Feb. 6, 1952 5 SheetsSheet 1 I N VEN TOR.

UM h/7W May 11, 1954 c. B. SPASE ETAL 2,673,031

RADIATOR FAN AND COOLANT IMPELLER SPEED CONTROL MECHANISM Filed Feb. 6, 1952 3 Sheets-Sheet 2 INVEN 0R.

May 11, 1954 c. B. SPASE ETAL 2,678,031

RADIATOR FAN AND COOLANT IMPELLER SPEED CONTROL MECHANISM Filed Feb. 6, 1952 3 Sheets-Sheet 3 NVENTOR. char/e5 5. p i Edv/HL-Waare Patented May 11, 1954 oFFic RADIATOR. FAN COOLANT IMPELLER SPEED CQNTROL MECHANISM Charles B. Spase, Nedrow, and David L. Moore,

Syracuse, N. Y., assignors to Lipe-Itollway Corporation, Syracuse, N. Y., a corporation of New York Application February 6, 1952, Serial No. 270,186

4 Claims. (01. 123-4111) This invention relates to cooling systems for liquid cooled internal combustion engines, which systems comprise a pump for circulating the liquid coolant through the jacket of the engine block from the radiator, and a fan for drawing outside air through the radiator. The fan and the pump are driven from the crank shaft of the engine at a fixed ratio, or ratios, of speed between the engine crank shaft and the fan and the pump, the ratio being such that the pump and the fan work most efficiently at relatively low vehicle speeds when the greatest heat is usually developed in the engine. At higher speeds, oftentimes the pump runs too fast and causes cavitation. That is, causes the formation of pockets on the inlet side of the pump impeller. The pockets may have a partial vacuum therein, or may contain vapors or gases which are under pressure formed from the coolant liquid so that the density of the coolant is reduced and bubbles formed therein, with the result that the engine is not adequately cooled and becomes overheated. The pump impeller at high R. P. M. above a predetermined R. P. M. thus causes cavitation and acts somewhat as a check valve retarding the flow of the liquid coolant. Also, the fan rotating at a predetermined R. P. M. moves the air through the radiator at a speed and volume to effect maximum eiiicient cooling. At higher speeds above the predetermined R. P. M., the fan may slip through the air and do something like merely cutting a hole in the air Without pumping the air through the radiator. Also the air, through the radiator, may be moved at higher speed so fast that it does not absorb much heat from the radiator but, on the contrary by the friction of the air passing through the radiator, may generate heat in the radiator.

This invention has for its object a radiator fan and coolant impeller speed control mechanism for liquid cooled internal combustion engines by which the speed of the fan and also the speed of th coolant impeller are regulated to maintain a comparatively constant predetermined rotary speed under high R. P. M. of the engine so that at higher engine speeds, the fan and the cool ant impeller rotate at predetermined lower speeds to pump a volume of air for efficient radiator cooling and to pump the coolant without cavitation.

The mechanism comprises a fan element, a casing having an intake and outlet connected in a coolant liquid circulating system, a pump or impeller element in the casing, an engine actuated drive wheel rotatable relatively to both elements, and a releasable friction clutch means ineluding friction clutch shoes carried by and rotatable with at least one of said elements, and a clutch surface on the drive wheel with which the shoes frictionally engage, the clutch shoes being spring pressed and movable centrifugally outward to reduce the friction pressure on the friction surface, or surfaces, of the wheel as the speed of the elements carrying the friction shoes increases above a predetermined R. P. M., whereby both the speed of the fan element and the speed of the impeller element remain at predetermined maximums at all engine R. P. M. above a predetermined R. P. M. of the engine.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawings in which like characters designate corresponding parts in all the views.

Figure 1 is a longitudinal sectional view of a mechanism embodying this invention.

Figure 2 is a View, similar to Figure 1, of a slightly modified form of the invention.

Figure 3 is a sectional View on line 3-3, Figure 1.

l designates the fan element, 2 the impeller or pump element, and 3 the casing in which the pump element is located, the casing having an inlet ti leading from the radiator 5, and an outlet 6 leading to the jacket, or other parts to be cooled of the engine.

I designates a drive wheel, as a pulley, usually actuated as by a V belt from the engine crank shaft, the pulley being shown as mounted to rotate about a shaft 8 to which at least one of the elements before referred to is keyed, the pulley '5 being here shown as mounted on an antifriction bearing 9, the inner raceway of which is a sleeve is rotatable with the shaft 8.

In Figure 1, the rotation of the pulley l is transferred to both the fan I and the impeller 2 through centrifugally releasable clutches which act independently of each other to release at the same, or at differential rotative speeds of the fan and the impeller to hold the rotation of the fan I and impeller 2 to predetermined maximum R. P. M.s to move the maximum volume of air for efficient cooling without fan slippage and to pump a maximum volume of coolant to effect efiicient cooling without cavitation.

As here shown, the centrifugally releasable clutch means are similar in construction and each includes a series of friction shoes 5 i or HA frictionally engaging with a peripheral friction surface 52 or I2A on each side of the drive wheel 'I', and springs I3 or I 3A acting to press the shoes H or HA radially inward and permit them to move radially outward under the centrifugal force, the springs thrusting against the rim of a cup-shaped holder member I4 or MA, the cupshaped member or holder I4 being secured at I5 to the fan, and the cup-shaped member MA being connected to the pump element 2 by being secured to a collar I5 keyed at I? to the shaft 8. The fan I itself is carried by a collar I8 which carries the outer race of an antifriction bearing I9, the inner race of which rotates with the sleeve I so that the fan is capable of rotating about the shaft 8, or the shaft 8 capable of rotating relatively to the fan I. The springs I3 and [3A may be the same, or of different weights. They are selected for the situation in which the mechanism is to be installed in preference to being made adjustable. Thus in the operation of the form shown in Figure 1, the rotation of the drive wheel 1 is transferred to the fan I and to the impeller 2 in accordance with the speed requirements incidental to the efficient operations of the fan I and of the impeller 2.

In the operation of the form shown in Figure 1, the drive wheel I is rotated at the speed of the engine shaft and when the speed of the wheel '5 reaches an R. P. M. above the most efficient speed of the fan I to move the maximum volume of air, the clutch embodying the shoes I I will begin to slip and release the fan at higher speeds and finally fully release the clutch. The same operation will take place with regard to the shoes II A when the speed of the impeller 2 is rotating at the highest point of its maximum efficiency without creating cavitation, although the shoes ii and the shoes IIA may release at different speeds because of the different loading of the springs I3 and I3A. Thus, the rotation of the drive wheel is metered to the fan I and to the impeller 22 to hold the fan and the impeller in their speed ranges of highest efficiency.

in the form shown in Figure 2, the rotation of the drive wheel I is metered only to the fan element I, or to the impeller element 2 or, in othe words, there is no differential rotation between the fan element I and the impeller element 2, as in Figure 1. Therefore, in Figure 2 there is but a single centrifugal clutch between the drive wheel and one of said elements, as the fan element I, and both the fan and its hub and the impeller element 2 are keyed at IA and 2A respectively to a common motion transmitting means to which both the fan and the impeller are keyed, as to the shaft 8. In the form of the invention shown in Figure 2, the speed of the shaft 8, as controlled by the clutch embodying the friction shoes I I may he the same insofar as efficient cooling is concerned of the radiator by the volume of air pumped by the fan I and the speed of the impeller 2 is concerned to prevent cavitation.

Figure 3 illustrates the construction of either of the fiction clutches. The annular wall of the cup-shaped holder I4 is formed with recesses 2! in which the friction shoes shift radially. The springs iii are located in recesses in the shoes and thrust against abutments 22 at the outer ends of the recesses, which abutments have heads against which the outer ends of the springs thrust. These heads may be screws in order to adjust the loading of the springs but it is preferable that the springs be selected of the right loading for the particular situation in which they are to be used.

The specific construction of the centrifugally releasable clutch means forms no part of this invention.

It is old to limit the speed of the fan by centrifugal clutch means as the speed is limited to a predetermined high to prevent overheating of the engine at which the fan works most efficiently. The fan works inefiiciently above the predetermined limited high R. P. However, it is not recognized, or realized, that inefficient cooling is due to two causes, one being the speed of rotation of the fan, and the other the speed of rotation of the pump impeller causing cavitation above a certain given R. M., and both forms of this invention illustrated in Figures 1 and 2 are intended to automatically correct both of these disadvantages, or causes, of overheating. Therefore, the maximum speed o the fan and of the impell r 2 for efiicient coo g operation of both is set at a higher ratio than in conventional constructions, the an being set to rotate at a ratio of 1.2 R. P. M. to 1 with respect to the rotation of the engine shaft until a predetermined R. P. M. of the fan and the peller is reached and the centrifugal clutch, or clutches, release.

What we claim is:

1. A radiator fan and cooantdnit-ellcr speed control for liquid cooled intecombustion engines comprising a fan e1e1nen-., a casing h ving an inlet and an outlet for connection in the liquid cooling circulating system of an engine, a pump element in the casin an engine actuated drive wheel mounted to ro ate relatively to both of said elements at an R. N. above predetermined P. M., normally engaged centrifugally releasable friction clutch means be tween the drive wheel and said elements comprising friction shoes mounted in holder means rotatable with said elements and spring pressed radially inward into engagement with annular friction face means on he drive wheel.

2. The mechanism of cl im 1 in which the clutch means corn lees two indivicl" I normally engaged centrifugally r asable clutches, clutch for each of said eler ents, two sets of tion shoes, two holder means for each set of shoes, the holder means being rotatable with. fan and said pump element respectively.

3. A radiator and coolant-impeller speed control for liquid cooled internal combustion engines comprising a fan element, a having an inlet and an outlet for connection in the liquid cooling system of an engine, a pump element in the casing, a shaft arranged coaxial with said elements, the pump element being keyed to the shaft and the fan element beinr rotatable about the shaft, an engine actuated drive wheel mounted concentric with the shaft between. said elements and mounted to rotate about the shaft and normally engaged clutches between opposite sides of the drive wheel e gines comprising a fan element, a casing having an inlet and an outlet for connection in the liquid circulating system of an engine, a pump element in the casing, a shaft coaxial with said element, said elements being spaced apart along the shaft and keyed to the shaft, an engine actuated drive wheel mounted between said elements concentric with the shaft and also mounted to rotate about the shaft, and a normally engaged clutch between one side of the drive Wheel and one of said elements comprising a set of friction shoes, and a holder for the shoes mounted to rotate with said one of the elements, and loaded springs for pressing the shoes radially inward against an annular friction face on the drive wheel.

References Cited in the file of this patent Number Number UNITED STATES PATENTS Name .Date Trotter Oct. 20, 1914 R005 Nov. 25, 1930 Wilson June 18, 1935 Spase May 2, 1950 Lee Aug. 19, 1952 FOREIGN PATENTS Country Date Great Britain Dec. 6, 1938

Images