US2899941A

US2899941A - Fluid motor

Info

Publication number: US2899941A
Authority: US
Publication date: 1959-08-18
Anticipated expiration: 1976-08-18

Description

18, 1959 c. E. ADAMS 2,899,941

FLUID MOTOR Original Filed Dec. 17', 1954 2 Sheets-Sheet 1 M J I 47 A w mvHmn m N @W H n: 2 W m MW 5. 8 H mQ 9 J N n nm L I CECIL E. ADAMS 1959 c. E. ADAMS 2,899,941

. FLUID MOTOR Original Filed Dec. 17; 1954 2 Sheets-Sheet 2 FIG. 2.

INVENTOR. CECIL E. ADAMS QM/W FIG. 3.

FLUID MOTOR Cecil E. Adams, Columbus, Ohio, assignor to American Brake Shoe Company, New York, N.Y., a corporation 'of Delaware Original application December 17, 1954, Serial No. 475,994. Divided and this application September 2,

I 1958, Serial No. 758,461

5 Claims. (Cl. 121- 86) This application isra division of my application Serial No.' 475,994, filed December 17, 1954, for a Hydraulic Transmission and Control Mechanism.

The present invention relates to fluid motors of the type which may be employed, for example, in a hydraulic transmission system of the type which is employed in automotive vehicles to drive an air conditioning apparatus thereof.

1 An object of this invention is to provide an improved fluid motor which may be employed in a hydraulic system of the typeset forth which motor has a novel valve means incorporated therein that is responsive to the volume of fluid supplied thereto by a pump to render the motor operative or inoperative and which is also effective as a safety device to by-pass fluid around the motor a'ndto exhaust in the event the motor is loaded unduly, whereby the motor as well as system in which it is em- 1 ployed are protected against injury in the event certain troubles develop therein.

Another object of the invention is to provide a fluid motor having an inlet, a rotor chamber and an outlet and a by-pass passage directly connecting the inlet and.

close the valve and direct all the fluid through the rotor chamber, the valve biasing means being operative again to move the valve to the by-pass passage opening position in the event excessive opposition is offered to the operation of the fluid motor. i A still further object of the invention is to provide a fluid motor having inlet, rotor and outlet chambers and a .'.movable partition dividing the inlet chamber into sec- :tions, one thereof being connected directly with the outlet --chamber by a by-pass passage, the partition carrying a valve element for opening and closing the by-pass passage :in response to movement of the partition, the latter being moved in response to pressure differentials caused by fluid .flow through an orifice establishing restricted communi- -:cation between the sections of the inlet chamber formed by the partition, means being provided to cause differentials in areas on opposite sides of the partition so that, in the event fluid pressures at opposite sides thereof are 'equal, forces on opposite sides will be unequal and the partition will be urged in a direction to cause the valve elementto open the, by-pass passage and direct fluid to exhaust without operating the motor. I

Further objects and advantages of the present invention .will be apparent from the following description, reference being had to the accompanying drawings where- :in-a preferred form of embodiment of the invention is Patented Aug. 18,

of the apparatus being shown diagrammatically and other parts being shown in longitudinal section;

Fig. 2 is a vertical sectional view taken through the fluid motor seen in Fig. 1, the plane of the section being indicated by the line 22 of Fig. 1, and

Fig. 3 is a fragmentary longitudinal sectional view taken through the motor and showing parts thereof in positions different from that shown in Fig. 1.

Referring more particularly to the drawings and especially Fig. 1, the numeral 20 designates one form of a combined hydraulic system and electrical circuit of which a hydraulic motor which includes the features of the invention forms a part Apparatus 20 includes a refrigerating system 21 which is shown diagrammatically and includesa compressor 22, a condenser 23, an expansion valve 24, an expansion coil or evaporator 25, and a fluid line 26 leading from the latter to the inlet of the 1 compressor 22.

35 extending from the outlet of the fluid motor to the cooler and backto the reservoir 32.

The pump 28 is of the type shown in the co-pending application of Cecil E. Adams et al., Serial No. 416,768,

filed March 17, 1954, to which reference may be had for a detailed description, Since this pump forms no part of the present invention, it need only be pointed out here that it is a pump the output volume of which may be adjusted to deliver an infinite number of constant output volumes and a pump which is self-adjusting to maintain the output volume for which it is adjusted even though the speeds at which its shaft are driven may vary. Pump 28 is to be driven by the engine, not shown, of the vehicle to which the air conditioning system is to be applied.

The operation of the pump has been fully explained in copending application Serial No. 416,768, above-identified, and for the purposes of this application, it is suflicient to state that, as it is driven by the engine of the vehicle fluid is drawn from the conduit 33 into the pump and is expelled therefrom into the conduit 34. The volume of fluid flowing from the pump discharge port into line 34 will be maintained as determined by the setting of an adjustable lever or knob 91.

' Motor 28 includes a pair of easing sections and 96, a pair of cheek plates 97 and 98 and a cam ring 100 disposed and clamped between the cheek plates. The casing sections, cheek plates and cam ring cooperate to provide the casing with inlet, rotor and outlet chambers 101, 102

'and 103, respectively. The rotor chamber receives a rotor 104 which is mounted on a shaft 105 supported for rotation in bearings carried by cheek plates 97 and 98. The rotor has radially extending slots formed therein to receive vane elements 106 which are spring urged outwardly for engagement with the internal surface of the cam ring 100. This surface is generally of elliptical form, the ends of the ellipse being spaced a greater distance from the outer surface of the rotor 104 than the sides to form-l working chambers 107, as shown in Fig. 2. Inlet and

outlet ports

108 and 109 are formed at the opposite ends of the working chambers, the inlet ports communicating with' the inlet chamber 101 and the outlet ports communicating with the outlet chamber 103. Fluid supplied to the motor through line 34 will flow through the inlet chamber 101, through the inlet ports 108 to the rotor chamber and will apply force to one side of the .vanes 106 in the working chambers and tend to urge element.

As shown in Fig. l, cheek plate 98 and the shaft 105 of the motor 30 are provided with openings and passages 111 and 112 which directly establish communication between the inlet chamber 101 and the outlet chamber 103. The opening 111 in cheek plate 98 forms a seat for a valve element 113 which, in the present instance, is carried by a partition 114, this partition being arranged in the inlet chamber 101 for limited longitudinal movement. The partition divides the chamber 101 into a pair of sections 115 and 116, the latter of which communicates directly with the passage 34 while the other communicates with the rotor chamber. The opening 111 in cheek plate 98 and the passages 112 in shaft 105 communicate with the section 115 of the inlet chamber. Partition 114 and the valve element 113 carried thereby are urged in a direction away from the cheek plate 98 by a coil spring 117 so that, normally, when fluid is not flowing through the .motor 30 or only a relatively small amount of fluid is flowing therethrough, the inlet chamber 101 will be directly connected with the outlet chamber by the opening 111 and passages 112 in cheek plate 98 and shaft 105. Fluid may then flow from the inlet chamber to the outlet chamber without flowing through the rotor chamber and -the motor will then be idle.

Sections 115 and 116 of the inlet chamber communicate with one another through an orifice 118 formed in the partition. This orifice will create a pressure differential on fluid flowing through the orifice and, when a predetermined volume of fluid is supplied to the motor, the: higher pressure of the differential will be great enough to cause the partition to move toward cheek plate 98 and seat the valve element 113 against the perimeter of the port 111 formed in the cheek plate 98. The by-pass passage forrned by the port 111 and passages 112 will then be closed and fluid will be directed through the rotor chamber. Rotary movement will then be imparted to the shaft 105. As long as a suflicient amount of fluid flows through the motor to create the necessary pressure differential, the valve element will remain seated. When the volume of fluid supplied to the motor is reduced to a predetermined quantity, however, the pressure differential will not be maintained suflicient to overcome the force of the spring 117 and the valve element will be moved away from a by-pass passage closing position, the fluid supplied to the motor then being directed to the outlet port without passing through the rotor'chamber. motor will again be idle.

The partition 114 and valve 113 carried thereby have also been designed to serve as a relief valve or safety This object is accomplished by forming the casing section 96 with a boss-like projection 120 having a recess 121 formed therein to receive a hub 122 formed on the partition 114. This hub is received for sliding movement in the recess, the construction serving to create a differential in areas exposed to fluid'pressure in the sections of the inlet chamber 101.

As shown in Fig. 1, hub 122 is drilled as at 122A to provide restricted communication :between the inlet chamber section 116 and the recess 121. This communication will permit fluid to escape from the recess to the chamber section 116 when the partition is moved under the influence of spring 117 to space valved-113 from its seat. The valve element 113 is formed with a central passage 123 to establish communication between the recess 121 and the port 111, a spring pressed check valve 124 being provided in the valve element 113' to normally close this passage :and interrupt flow therethrough. When the pressure'in The the recess increases sufficiently, however, the check valve 124 will open to permit fluid to flow from the recess to the by-pass passage and forces on opposite sides of the partition will be unbalanced. These unbalanced forces will cause the partition to move and withdraw the valve element 113 from the seat in cheek plate 98 to open the by-pass passage. This operation will occur in the event an excessive load is applied to the'shaft of the fluid motor 30. When this excessive load is applied, the pressure in the sections and 116 of the inlet chamber 101 will be equalized through the orifice 118 but, since there is a differential of areas on opposite sides of the partition 114 exposed to this pressure and the greater-area is exposed to section 115 which communicates with the rotor chamber, the partition will be moved causing fluid to be expelled from the recess 121 and the valve element 113 to be moved to a bypass passage opening position. Fluid then flowing to the pump will pass from the inlet chamber directly to the outlet chamber while the motor, is permitted to stand idle. The partition and valve elements are shown in the position just described in Fig. 3. Arrows are employed to show the application of the greater force to the partition to move the valve away from the valve seat.

One of the features of the apparatus shown in Fig 1 is that it includes a novel control mechanism whereby the rate of operation of the compressor 22 may be controlled simultaneously with the rate of operation of an electrically operated fan 125 employed to circulate over the evaporator. This control mechanism is shown diagrammatically in Fig. l. The control mechanism includes an actuating lever 126 which is mounted for pivotal movement in a location convenient for actuation by the operator of the vehicle. The lever has a pair of arms 127 and 128, the former of which is connected by a motion transmitting device 130, in this instance a push-pull wire, with the lever or knob 91 used to vary the output volume of the pump 28. When the control lever is moved in one direction, the wire wil-l transmit .such motion to the knob 91 to change its position and thereby change the volume of fluiddelivered by the pump and consequently the rate of operation of the ,motor 30. Since motor 30 is connected with the compressor, the rate of operation of the latter will also be changed. It should be obvious that, if the control lever 126 is moved to decrease the output of pump 28 sufficiently, the operation of motor 30 and the compressor may be interrupted. If the control lever is moved in the opposite direction, the volume of fluid discharged by the pump will be increased and the rate of operation of the motor 30 and the compressor will be increased. When the compressor operating rate is increased, the evaporator Will cause an increased cooling effect and consequently it is desirable to increase the volume of air flowing over the evaporator. The control lever 126 has, therefore, been provided with the second arm 128 which has a contact element 129 for cooperation with a variable resistance 131 connected in the circuit for the electric motor coupled with the fan 125. This arrangement permits the fan to be operated at various rates depending upon the position of the control lever. If the control is moved to increase the volume of fluid supplied to the fluid motor, the supply of current to the electric motor for the fan will also be .increasedto cause the fan to operate at a faster rate.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow:

I claim: a

1. In a fluid motor, a casing forming a rotor chamber, inlet and exhaust chambers at opposite sides of said rotor chamber and inlet and outlet ports communicating with said inlet and exhaust chambers, respectively; a

shaft in said casing; a rotor in said rotor chamber driving said shaft, fluid flow through said rotor chamber imparting rotary motion to said rotor and shaft; means forming a passage establishing communication directly between said inlet and exhaust chambers and by-passing said rotor chamber; a valve element supported for move ment between positions opening and closing said passage; a first means urging said valve toward the position opening said passage; a second means in said inlet chamber responsive to fluid pressure to urge said valve toward the position closing said passage; and means forming a restricted orifice through which fluid flows to said rotor chamber, said restricted orifice creating a back pressure which is applied to said second means to cause said valve to close said passage.

2. In a fluid motor, a casing forming a rotor chamber, inlet and exhaust chambers at opposite sides of said rotor chamber and inlet and outlet ports communicating with said inlet and exhaust chambers, respectively; a shaft in said casing; a rotor in said rotor chamber driving said shaft, fluid flow through said rotor chamber imparting rotary motion to said rotor and shaft; means forming a passage establishing communication directly between said inlet and exhaust chambers and by-passing said rotor chamber; a partition supported in said inlet chamber for limited movement; a valve element carried by said partition for movement toward and away from a position closing said passage; means urging said par tition and valve away from a passage closing position; and means forming a restricted orifice establishing communication between spaces in said inlet chamber at opposite sides of said partition, said orifice creating a back pressure which tends to urge said partition and valve toward a passage closing position.

3. In a fluid motor, a casing forming a rotor chamber, inlet and exhaust chambers at opposite sides of said rotor chamber and inlet and outlet ports communicating with said inlet and exhaust chambers, respectively; a shaft in said casing; rotor means in said rotor chamber driving said shaft, fluid flow through said rotor chamber imparting rotary motion to said rotor means and shaft; a partition supported in said inlet chamber for limited movement and dividing said inlet chamber into high and low pressure sections and having surface areas exposed to each of said sections; means forming a passage establishing communication between said low pressure section and said exhaust chamber and by-passing said rotor chamber; a valve element carried by said partition for movement toward and away from a position closing said passage means; means urging said partition and valve away from said passage closing position; said partition forming an orifice establishing restricted communication between said high and low pressure sections in said inlet chamber through which fluid flows to create different pressures in said high and low pressure sections the diflerence between which urges said partition and valve to said passage closing position upon a predetermined flow of fluid through said orifice.

4. In a fluid motor, a casing forming a rotor chamber, inlet and exhaust chambers at opposite sides of said rotor chamber and inlet and outlet ports communicating with said inlet and exhaust chambers, respectively; a shaft in said casing; rotor means in said rotor chamber driving said shaft, fluid flow through said rotor chamber imparting rotary motion to said rotor means and shaft; a partition supported in said inlet chamber for limited movement and dividing said inlet chamber into high and low pressure sections and having surface areas exposed to each of said sections; means forming a passage establishing communication between said low pressure section and said exhaust chamber and by-passing said rotor chamber; a valve element carried by said partition for movement toward and away from a position closing said passage means; means urging said partition and valve away from said passage closing position; means establishing restricted communication between said high and low pressure sections in said inlet chamber through which fluid flows to create different pressures in said high and low pressure sections the diflerence between which urges said partition and valve to said passage closing position upon a predetermined flow of fluid through said orifice.

5. In a fluid motor, a casing forming a rotor chamber, inlet and exhaust chambers at opposite sides of said rotor chamber and inlet and outlet ports communicating with said inlet and exhaust chambers, respectively; a shaft in said casing; rotor means in said rotor chamber driving said shaft, fluid flow through said rotor chamber imparting rotary motion to said rotor means and shaft; a partition supported in said inlet chamber for limited movement and dividing said inlet chamber into high and low pressure sections and having surface areas exposed to each of said sections; means forming an exhaust passage for said low pressure section; a valve element carried by said partition for movement toward and away from a position closing said passage means; means urging said partition and valve away from said passage closing position; means establishing restricted communication between said high and low pressure sections in said inlet chamber through which fluid flows to create difierent pressures in said high and low pressure sections the difference between which urges said partition and valve to said passage closing position upon a predetermined flow of fluid through said orifice.

References Cited in the file of this patent UNITED STATES PATENTS