US2641194A - Power transmission - Google Patents

Description

June 9, 1953 G. M. JONES EIAL POWER TRANSMISSION Filed Oct. 20, 1950 28 INVENTORS GLEN HARVE N M. JONES BY Y H. DUVALL TTORNEY Patented June 9, 1953 UNITED STATES PATENT OFFICE Duvall, Detroit, Mich, assignors to Vickers 'I-neorporated, Detroit, Mich, a corporation of Michigan Application October 20, 1950, Serial No. 191,114

Claims.

This invention relates to power transmissions, and is particularly applicable to those of the type comprising two or more fluid pressure energy translating devices, one of which may function as a pump and another as a fluid motor.

The invention is more particularly concerned with a vane pump or motor construction adapted for use in hydraulic power transmission systems.

A form or pump in common use in the hydrau lic power transmission field utilizes a rotor hav ing a plurality of substantially radial vanes rotat able therewith and slidable relative thereto. The rotor is mounted within a chamber, the contour of which forms a vane track against which the outer ends of the vanes are adapted to be maintained in contact. The chamber forming the vane track may comprise the inner portion of a vane track ring. The vane track is adapted to control the movement of the vanes and cooperates with the rotor in forming working chambers through which the vanes pass as the rotor turns. The external connection ports lead by passage means to the working chambers so as to form separate fluid inlet and outlet zones.

Some means in addition to centrifugal force is utilized to maintain the outer ends of the vanes in contact with the vane track, which is essential for efficient operation. One method has been to connect the high pressure side of the device to the inner ends of the vanes. However, a problem arises in maintaining the contact when there is no pressure available. When the device is utilized as a motor it is particularly important at starting operation that some slight force be employed for urging the vanes outward in contact with the track, otherwise leakage would occur around the outer ends of the vanes and cause free wheeling of the device. It is also important that contact be maintained as the vanes pass over the sections forming the separation between the inlet and outlet fluid zones. In addition, as the vanes pass through the high pressure zone of the device, there is a tendency for the vanes to separate from the track because of the outer ends being exposed to said high pressure.

Attempts have been made to solve this problem by the use of individual coil springs for each vane and which have failed to meet commercial requirements. Ihe space available in the rotor for mounting the springs is very limited. Due to the fact that the spring is subjected to severe operating conditions, such as the numerous flexings of each spring and the speed at which they must contract and expand, they fatigue rapidly. In order to meet commercial operating requiremerits, the rotor size would have to be greatl increased to provide proper mounting area for the larger types of springs demanded. Ihis is impractical when size, weight and cost are to be considered.

Where the individual coil spring type of construction is utilized the spring is continuously subjected to the full travel of the vane. Where the device is of the double throw type, i. e., each vane havingtwo complete strokes per rotor revolution, and the rotor speed is in excess of 1000' R. P. M. it can be clearly seen that each spring is subjected to over 2000 full travel strokes of the vane each minute. The fatigue life of the coil spring is thus certain to be short.

In order to overcome the shortcomings of the individual coil spring type of construction, it has been heretofore proposed to utilize resilient bell crank members for 'preloading the vanes in contact with the vane track and which by lever action transfer the inward motion of one vane to outward motion of a complementary vane. In this latter type of construction the bell crank member is pivotally connected at its central portion to the rotor and the arms of the member which engage the under portions of a pair of complementary vanes resiliently preload the vanes in contact with the vane track. The motion of one vane is transferred to another comlementar vane without substantial flex'ure of the arms. However, a problem arises in roviding bell crank members constructed so that free pivotal movement of the adjacent arms of adjoinin'g members is permitted. A staggered relationship of the immediately adjacent arms of the member is desirable and the problem of cost including labor costs during assembly of the device must be considered.

It is therefore an object of this invention to provide an improved type of resilient bell crank member for preloadlng the vanes in contact with the vane track and for transferring by lever action the inward motion of one vane to the outward motion-of a complementary vane.

It is a further object of this invention to provide bell crank members for the purposes stated above, the arms of which engage the inner ends of the vanes being on the same plane and which may be economically mounted in a staggered relationship on the rotor to provide free pivotal movement of adjacent members.

It is also an object of this invention to provide bell crank members of an improved construction for the purposes aforementioned which are economical and eflicient over a long useful life.

It is another object of this invention to provide members of the type and for the purpose mentioned which are resilient so as to produce the preloading effect of the vanes desired but arranged to produce the lever action required without significant bending action as the vanes travel throughout their full strokes.

It is another object to provide a novel, economical, improved means for selectively preloading the vanes in contact with the vane track which is efficient over a long useful life.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred form of the present invention is clearly shown.

In the drawing:

Figure 1 is a sectional view of a rotary vane pump or motor.

Figure 2 is a sectional view taken on line 2-2 of Figure 1 embodying a preferred form of the present invention.

Figure 3 is an enlarged partial sectional view of the rotor illustrated in Figure 2.

Figure 4 is a partial sectional view illustrating the staggered relationship of the bell crank members on opposite sides of the rotor.

Referring to Figure 1, there is shown a rotary vane type of pump or motor indicated generally by the numeral ID, the body of which comprises a right end housing member l2 and left end housing member I4 sandwiched between and suitably bolted to which is a central housing member or cam ring IS. The right end housing member I2 is provided with an external connection port I8 and the left end housing member with an external connection port 20.

The inner-contour of the cam ring I6 indicated by the numeral 22 is substantially elliptical in shape. Mounted within the cam ring i6 is a rotor 24 provided with a plurality of substantially radial slots 26 within which vanes 28 of rectangular shape are slidably mounted. The outer ends of the vanes are adapted to be urged in contact with the contour of the cam ring, which will hereinafter be referred to as the vane track, by pressure fluid directed to the inner enlarged ends of the slots and indicated by the numeral 30.

Pressure fluid is adapted to be conducted to the enlarged portions 30 from a pressure chamber 32 connected to the external port 20. The pressure chamber 32 is connected to the enlarged portions of the vane slots by means of a plurality of ports 34 in a side plate 36 mounted in the pressure chamber 32. The side plate 36 is initially urged against a portion of the cam ring l6 and in fluid sealing engagement with the rotor 24 by a spring 38. During operation of the device pressure fluid in the pressure chamber which is equivalent to the pressure in port 20 will maintain the side plate in fluid sealing engagement with the rotor 24.

The rotor is provided with a shaft 40 spline connected thereto at 42 and which is rotatably mounted on bearings 44 and 46 within the right end housing member [2. The port I8 is connected by branch passages 48 and 50 which open to diametrically opposed working chambers 52 and 54 of the device. A pair of diametrically opposed fluid openings in the side plate, not shown, are adapted to connect other remaining portions of the working chamber to the pressure chamber 32 which is connected to the port vanes.

The contour of the cam ring cooperates with rotor and vanes to produce two complete inward and outward strokes of each vane during a rotor revolution. For each vane on an inward stroke there is a complementary vane which is on a corresponding outward stroke. The complementary vanes in the double throw unit shown are degrees apart but it should be understood that in a single throw unit the spacing will be degrees, in a triple throw unit 60 degrees, etc. For the purpose of preloading the vanes in contact with the vane track 22, such as for maintaining the outer edges in contact therewith at starting and when there is no pressure, there is provided a plurality of bell crank members 56. Each member is provided with two arms 58 and 60 which are in the same plane and the member is partially coiled or looped at its central portion indicated by the numeral 62. The bell crank members 56 are mounted in circular recesses 64 formed in opposite faces of the rotor 24 and on extending portions 61 of pins 68 rotatably mounted in bores 10 opening at opposite ends to the recesses. Each pin 68 is provided with a groove 12 near each end portion thereof and the central portion 62 of the member 56 may be snapped into the groove so as to be pivotally connected to the rotor. The bell crank members lie between the planes containing the axially spaced edges of the The arms of each member underlie the inner ends of all intermediate vanes within the span between complementary vanes and are bent to avoid interference with intermediate vanes and at their ends to engage the inner ends of complementary vanes in a manner to resiliently load said vanes in engagement with the track.

Due to the fact that the arms of the members 56 are on the same plane, free pivotal movement of the members so as to produce a lever action by the arms thereof, is provided by staggering these members on opposite sides of the rotor. Washers T2 are provided for alternate members on each side of the rotor. They are placed on the ends of the pins between the rotor and the bell crank member, and the looped portion of the member retains the washer on the pin. In this manner, each member is staggered in position with respect to the adjoining members on each side of the rotor.

In operation as one vane begins an inward stroke, its complementary vane will begin an outward stroke. As the vane track causes the inward stroke of each vane the inward motion thereof will be transferred by lever action by one arm of the member to produce an outward or upward motion of the other arm and its complementary vane. The arms of the members, being resilient, preload the vanes in contact with the vane track 22. This is an important advantage at starting when operating the device as a motor. In addition when operating the device as a motor it is advantageous to provide an additional force to maintain the vanes in contact with the rings when they pass through the inlet fluid zones of the working chambers. At this time there is a tendency for the vanes to separate from the vane track which would cause leakage and free wheeling. The arms are of sufficient strength to produce by lever action the outward motion of one vane by transferring thereto the inward motion of its complementary vane without substantial flexure of the arms of the member.

The construction therefore avoids the disadvantages of prior constructions wherein individual coil springs were provided for each vane which were repeatedly subject "to compression leading to short fatigue life. The arrangement whereby a washer is placed behind alternate members at the central portion thereof provides an economical means of providing a, staggered relationship of alternate members on opposite sides of the rotor. This simplifies the construction of the bell crank members and its associ ated mounting parts and provides free pivotal movement of the adjoining members.

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

What is claimed is as follows:

1. In a fluid pressure energy translating device of the rotary vane type comprising a "housing having a vane track and a rotor mounted within the track having a plurality of generally radial slots, each slot having a vane slidably mounted therein the outer end of which is adapted to be constantly urged against the track, said track causing complete inward strokes of the vanes during a rotor revolution and each vane on an inward stroke having a complementary vane adapted to be on an outward stroke, that improvement comprising a plurality of bell crank members each of which is pivotally mounted at its central portion on the rotor between a pair of complementary vanes, the arms of each member underlying the inner ends of all intermediate vanes within the span between complementary vanes and the outer ends of the arms engaging the inner ends of complementary vanes, said arms of each member being flexible to resiliently load the vanes in engagement with the track and being of suiiicient strength to transfer by lever action without substantial flexure the inward motion of one vane to its complementary vane to cause the outward stroke of said vane, the arms of each member being on the same plane, and means staggering the members in two planes on the rotor to avoid interference between the arms of adjacent members.

2. In a fluid pressure energy translating device of the rotary vane type comprising a housing having a vane track and a rotor mounted within the track having a plurality of generally rad1al slots, each slot having a vane slidably mounted therein the outer end of which is adapted to be constantly urged against the track, said track causing complete inward strokes of the vanes during a rotor revolution and each vane on an inward stroke having a complementary vane adapted to be on an outward stroke, that 1mprovement comprising a plurality of opposing pairs of bell crank members on the rotor, each of which is pivotally mounted at its central portion on the rotor between a pair of complementary vanes, the arms of each member being bent to avoid interference with all intermediate vanes within the span between complementary vanes and at their outer ends to engage the inner ends of complementary vanes, said arms of each member being flexible to resiliently load the vanes in engagement with the track and being of sufficient strength to transfer by lever action without substantial flexure the inward motion of one vane to its complementary vane to cause the outward stroke of said vane, the arms of each member being on the same plane, and means for staggering alternat members in two planes on opposite sides of the rotor to avoid interference be tween the arms of adjacent members.

3. In a fluid pressure energy translating device of the rotary vane type comprising a housing having a vane track and a rotor mounted within the track having a plurality of generally radial slots, each slot having a vane slidably mounted therein the outer end of which is adapted to be constantly urged against the track, said track causing complete inward strokes of the vanes during a "rotor revolution and each vane on an inward stroke having a complementary vane adapted to be on an outward stroke, that improvement comprising a plurality of bell crank members each ogfwhich comprises a single strand of wire having a loop at its central portion and the'arms of which are in the same plane, a plurality of pivot pins mounted'in the rotor the ends of which extend from thearo'tor. one between each pair of complementary vanes, and a bell crank member pivotally mounted on each end of each pin, the members being mounted by their loop portion on the ends of said pins, the arms of each member being bent to avoid interference with all intermediate vanes within the span between complementary vanes and at their ends to engage the inner ends of a pair of complementary vanes, said arms of the members being flexible to resiliently load the vanes in contact with the track and of sufilcient strength to transfer the inward motion of one vane to its complementary vane to cause the outward stroke of said vane, and means for staggering the members in two planes on the pins to avoid interference between the arms of adjacent members.

4. In a fluid pressure energy translating device of the rotary vane type comprising a housing having a vane track and a rotor mounted within the track having a plurality of generally radial slots, each slot havin a vane slidably mounted therein the outer end of which is adapted to be constantly urged against the track, said track causing complete inward strokes of the vanes during a rotor revolution and each vane on an inward stroke having a complementary vane adapted to be on an outward stroke, that improvement comprising means forming recesses on opposite faces of the rotor, a plurality of pivot pins mounted in the rotor the opposite ends of which extend into the recesses, one between each pair of complementary vanes, a plurality of bell crank members each of which comprises a single strand of wire having a loop at its central portion and its arms on the same plane, said bell crank members being pivotally mounted by their loops on the pins, there being one bell crank member on each end of each pin, the arms of each member being bent to underlie the inner ends of all intermediate vanes within the span between complementary vanes and at their outer ends to engage a pair of complementary vanes, said arms being flexible to resiliently load the vanes in engagement with the track and of suificient strength to transfer by lever action without substantial flexure the inward motion of one vane to its complementary vane to cause the outward stroke of said vane, and means for staggering alternate members in two planes on the pins on opposite sides of the rotor to avoid interference between the arms of adjacent members.

5. In a fluid pressure energy translating device of the rotary vane type comprising a housing having a vane track and a rotor mounted within the track having a plurality of generally radial slots, each slot having a vane slidably mounted therein the outer end of which is adapted to be constantly urged against the track, said track causing complete inward strokes of the vanes during a rotor revolution and each vane on an inward stroke having a complementary vane adapted to be on an outward stroke, that improvement comprising a plurality of bell crank members each of which is pivotally mounted at its central portion on the rotor between a pair of complementary vanes, said bell crank members lying between the planes containing the axially spaced edges of the vanes and the arms being bent to avoid interference with all intermediate vanes within the span between complementary vanes and at their outer ends to engage the inner ends of complementary vanes, said arms being onthe same plane and being flexible to resiliently load the vanes in engagement with the track, and said arms being of sufli'cient strength to transfer by lever action without substantialflexure the inward motion of one vane to its com-' plementary vane to cause the outward stroke thereof, and means for staggering the members 5 in two planes on the rotor to avoid interference between the arms of adjacent members.

GLENN M. JONES. HARVEY H. DUVALL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,284,083 Flinn Nov. 5, 1918 15 1,303,745 Vogan May 13, 1919 FOREIGN PATENTS Number Country Date 499,923 France 1919

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