US2910008A

US2910008A - Pump

Info

Publication number: US2910008A
Application number: US477288A
Authority: US
Inventors: Charles O Weisenbach
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1954-12-23
Filing date: 1954-12-23
Publication date: 1959-10-27
Anticipated expiration: 1976-10-27
Also published as: FR1143303A

Description

Oct. 27, 1959 v c. o. WEISENBACH 0,

I PUMP I Filed Dec. 25, 1954 I 3 Sheets-Sheet l IN VEN TOR.

M m we Oct. 27, 1959 C. O. WEISENBACH PUMP 3 Sheets-Sheet 2 Filed Dec. 23, 1954 0 INVENTOR. (944K155 .Wf/ ffi a M/r 959 c. o. WEISENBACH 2,910,008

PUMP

Filed Dec. 23, 1954 3 Sheets-Sheet 5 CI... V

' IN VEN TOR. 7 0mm; 4 wm'mmr/l 2 1477??5) United States Patent PUMP , Application December 23, 1954, Serial No. 477,288

' V 1 Claim. (Cl. 103- 162) This invention relates generally to fluid pumps of the piston type and more particularly to an improved combination of such pumps embodying servo control means for adjusting the stroke'of a portion of said pistons.

It is an object of this invention to provide a unitary pumping device embodying two opposed piston pumps having a stroke adjusting control incorporated therein, and capable of a wide range of operation from substantially no flow to the discharge of large quantities of fluid at high pressure.

Another object of the invention is to provide a reversible Wobbler-type mechanism with a servo control means for adjusting the stroke of the pistons of one pump and the Wobbler therefor on'both sides of neutral as well as to its neutral or no stroke position.

Another object of the invention is to provide a variable delivery, unitary pumping deviceembodying two pumps having control means incorporated therein for operating one of said pumps as a motor during a portion of the operating range of said device.

Another object of the invention is to provide a high capacity, variable delivery pumping device that is of extremely small size, light weight and having high sensitivity of control.

Other objects and advantages of the invention will become readily apparent from the following description taken in connection with the accompanying drawings, in

which:

Figure 1 is atop view of my-invention;

Figure 2 is a longitudinal section taken along line 2--2 of Figure 1;- Figure 3 is a cross sectional View of Figure 1;

Figure 4 is a cross sectional view taken along line 4--4 of Figure 1; and

Figure 5 is a schematic view showing inlet and outlet connections of the pumping unit.

With reference to the accompanying drawings, numeral designates a pump housing or hollow body closed at either end by plates 12 and 14, the latter of which may form a portion of the housing 16 of a centrifugal pump 18 which is provided with an end plate 20. An inlet 22 and an outlet 24 are provided in a wall 26 which separates the interior of the housing into two chambers 28 and 30. Located in said chambers 28 and 30 are plunger housings or rotors 32 and 34, respectively, mounted in opposed relation on a common drive shaft 36 which is journalled in end plates 12 and 14 and at one a pumping device embodying taken "along line 3'-3 end is provided with a drive spline 38 which is adapted for connection with an engine (not shown).

Rotor 32 is constructed and arranged in operative position with one end parallel and in close proximity to a'port insert member 40 which is secured to the wall 26 by suitable pins 42. Port insert member 40 is provided with kidney shaped ports 44 and 46, best shown in Figure 5, which are in communication with inlet 22 and outlet 24 respectively through conduits 48 and 50.

2,910,008 Patented Oct. 27, 1959 Rotor 32 is formed with a plurality of cylinders 52 which are disposed at an angle to the axis of rotation of said rotor. As rotor 32 is rotated about its axis, cylinders 52 are arranged to successively register with ports 44 and 46. Sleeves 54 are located in the side wall of each of the cylinders 52 to provide a bearing surface for plungers 56 which are reciprocably disposed in said cylinders. Plungers 56 are urged inwardly, in a pumping or fuel displacing direction, by a wobble plate 58 which is fixed against rotation but which may be angularly varied about shaft 36 by suitable means to be described later. Plungers 56 may be moved outwardly in a fuel connection between rotor 32 and shaft 36 so that in event of casualty to said rotor the connection mayshear to permit the free rotation of shaft 36 and the continued operation of the remainder of the unit.

Rotor 34 is similar in construction to rotor 32 and is arranged in operative position in chamber 30 with one end parallel and in close proximity to a port insert member '70 which is secured to wall 26 by suitable pin 71. Port insert member is provided with kidney shaped ports 72 and 74 which are connected to the inlet 22 and outlet 24 through conduits 7 6 and 78 respectively. Rotor 34 is formed with a series of elongated bores or cylinders 80 which are adapted to sucecssively register with ports '72 and 74 as the rotor is rotated about its axis. In each of said cylinders 80 there is mounted a plunger or piston 82 positively urged in a fuel-displacing or pumping stroke direction by means of a non-rotating, fixed angle cam or wobble plate 84. Piston 82 may be returned during the intake stroke by centrifugal force, or by springs 86, each acting alone or in combination. A plunger return ring 88 secured to wobble plate 84 may be provided to assist in the return of plungers 82. Rotor 34 is driven by shaft 36 through a shear sectioned spline 90 to provide for free rotation of the shaft and continued rotation of the remainder of the unit in event of a casualty to said rotor.

Wobble plate 58 is mounted in the housing 10 on a trunnion 92 for rotation on either side of the neutral or no stroke position in response to regulation by a. servo mechanism designated generally at 100. With wobble plate 58 in the maximum pumping stroke position, at shown in Figure 2, the discharge from rotor 32 is maximum and is combined with the discharge from rotor 34 to give maximum flow from the variable delivery pumping unit. As the wobble plate or cam 58 is rotated clockwise from the maximum pumping stroke position to the neutral or no stroke position, the flow from the variable delivery unit is reduced to one half the maximum flow. Further rotation of the wobble plate 58 past the neutral position causes rotor 32 to be operated as a motor absorbing the discharge from rotor 34. With the wobble plate in the limit clockwise position, rotor 32 absorbs all or nearly all of the discharge from rotor 34 resulting in a substantially zero flow from the variable delivery pumping unit. In actual practice, however, it is usually desirable to maintain a minimum flow through the unit for cooling purposes. Tests have shown that rotor 32 can absorb about 96 percent of the output of rotor 34 without serious temperature rise.

A stop or limit member 102 is threadably secured in the housing 10 and is adapted to butt against wobble wobbleplate 58 to thereby insure a minimum flow I through the unit for cooling purposes.

The servo mechanism 100 consists of a piston 104 adapted to reciprocate in a cylinder 106 and has secured thereto a hollow rod 108 which projects through asuitable guide bore 110 formed in housing and connects by means of a link 112 with Wobble plate 58. Cylinder 106 is divided into two chambers114 and 116 by'piston 104. Chamber 114 is'incommunication with outlet 24' through passage 118. A bleed passage 120 formed inpiston 104 connects chambers 1 14 and 116. Chamber 116 is adapted to be connected to a suitable control means (not shown) by a conduit 122; A bleed passage 1-24 in piston 104 connects chamber 116 through conduit 126 and port 128 with chamber'28 which contains fuel at inlet pressure. A spring 130 is located in chamber 116 to urge piston 104 in a direction to produce maximum pumping stroke of plungers 56 in rotor 32.

The inlet 132 of centrifugal pump 18'may be connected to a source of fluid (not shown) to discharge fluid from outlet 134 through conduit 136 (dot-dash line) 'to th inlet 22 of the variable delivery pumping unit.

In the operation of my variable delivery pump unit, fluid is delivered from a source not shown to inlet 132 of centrifugal pump 18 where it is placed under pressure and discharged from outlet 134 through conduit 136 to inlet 22 of the variable delivery pumping unit. With both wobble plates 58 and 84 in the pumping position as shown in Figure 2, fluid passes from the inlet 22 through passages 48 and 76 to the kidney shaped ports 44 and 72 which are in registration with one or more cylinders 52 and 80 of rotors 32 and 34 respectively. Rotation of the common drive shaft 36 brings cylinders 52 and 80 into registration with ports 46 and 74 at which time wobble plates 58 and 84 force the plungers 56 and 82 inwardly to discharge fuel into

conduits

50 and 78 to be expelled through a common outlet 24. The inlet ports 44 and 72 are located in the plane passing through diametrically opposed cylinders 52 and 80 formed respectively in rotors 32 and 34. Outlet ports 46 and 74 are located in a plane passing through diametrically opposed cylinders 52 and 80 in rotors 32 and 34 respectively. The planes passing through the inlet and outlet ports intersect at a mid-point between two rotors.

Discharge pressure is conveyed to chamber 114 of the servo unit 106 through passage 118 to urge piston 104 to the right toward neutral or motor stroke position. Spring 130 in chamber 116 opposes the pressure in chamber 114 and urges piston 104 to the left toward maximum pumping stroke position. The pressure in chamber 114 is controlled by regulating the bleed through 120 by suit- 4 able means (not shown) connected to conduit 122 whereby piston 104 may be moved to any desired position between maximum pumping and maximum motor stroke position.

It is to be noted that rod 108 is connected to wobble plate 58 on the inlet side of the rotor 32 and is arranged so that the force of discharge pressure acting on the plungers 56 forms a couple with the force acting on servo piston 104 to provide substantially instantaneous reaction of the wobble plate in response to changes of the control means.

While only one embodiment of the invention has been shown and described in detail it will be understood that this is illustrative only and is not to be taken as a definition of the scope of the invention, reference being bad for this purpose to the appended claim.

I claim:

A fluid pressure apparatus comprising a housing a shaft in said housing; a pair of rotors mounted in opposed relation on said shaft; a plurality of cylinders in each of said rotors angularly disposed to said shaft, the cylinders in one of said rotors'being diametrically opposed to corresponding cylinders in the other of said rotors; a plunger in each of said cylinder; an inlet for each of said rotors, said inlets being located in theplane passing through diametrically opposed cylinders; means connecting said inlets; an outlet for each of said rotors, said outlets being located in a plane passing through diametrically opposed cylinders; means connecting said outlets; a fixed wobble plate in said housing adapted to engage the plungers in' one of said rotors; a movable wobble plate mounted in said housing for rotation on either side of a neutral position, said movable wobble plate being adapted for engagement with the plungers in the other of said rotors; and a servo mechanism responsive to outlet pressure and operatively connected to said movable wobble plate for controlling the position thereof.

Great Britain Oct. 29, 1952 A 4A1:- k.