US3869962A

US3869962A - Air motor

Info

Publication number: US3869962A
Application number: US298124A
Authority: US
Inventors: George E Austin; Jagdish C Kalyan
Original assignee: Compressed Air Products Inc
Current assignee: Compressed Air Products Inc
Priority date: 1972-10-16
Filing date: 1972-10-16
Publication date: 1975-03-11
Anticipated expiration: 1992-03-11

Abstract

An air motor is provided with passages for conducting high pressure air to the cylinders and passages for delivering lubricating oil to certain bearings of the motor. A conduit disposed internally of the motor receives air from one of the pressurized air passages and delivers it to a venturi located near the surface of oil in the sump of the motor. The venturi is effective to draw oil out of the sump and deliver it through the lubricating oil passages to bearings which mount a rotary valve of the motor.

Description

States Patent [1 1 Austin et a1.

[ AIR MOTOR [75] Inventors: George E. A'ustin, Mercer Island;

Jagdish C. Kalyan, Seattle, both of [21] App]. No.: 298,124

[52] U.S. Cl 91/46, 92/153, 184/6.5, 184/55 R, 91/180 [51] Int. Cl. F0lb 31/10 [58] Field of Search.... 184/55 R, 55 A, 56 R, 56 A, 184/6.l6, 6.5, 6.6, 6.26, 7 D; 91/46, 180; 92/73, 153, 154; 417/237 [56] References Cited UNITED STATES PATENTS 1,945,338 l/l934 Terry 92/153 2,663,339 12/1953 Verderber 91/46 X 69 i G5 64 620 '5 s 63 Mar. 11, 1975 Primary Examiner-Manuel A. Antonakas [57] ABSTRACT An air motor is provided with passages for conducting high pressure air to the cylinders and passages for de livering lubricating oil to certain bearings of the motor. A conduit disposed internally of the motor re ceives air from one of the pressurized air passages and delivers it to a venturi located near the surface of oil in the sump of the motor. The venturi is effective to draw oil out of the sump and deliver it through the lubricating oil passages to bearings which mount a rotary valve of the motor.

4 Claims, 5 Drawing Figures AIR MOTOR BACKGROUND OF THE INVENTION Aspirating devices have been used for circulating lubrication oil through a mechanism. Each of the patents to Tuttle U.S. Pat. No. 1,750,070 and Heftler et al. U.S. Pat. No. 2,205,559 discloses a venturi through which air passes to draw oil from a reservoir and circulate it to adjacent bearing surfaces. Delling et al. U.S. Pat. No. 2,047,672 discloses the use of steam passing through a venturi for drawing oil from a sump. Davis et al. U.S. Pat. No. 3,175,643 and U.S. Pat. No. 3,244,375 disclose aspirating devices in the suction of an air compressor for drawing oil into the system. The present invention provides an improved air motor lubricating arrangement.

SUMMARY OF THE INVENTION The present invention comprises an air motor having means for receiving pressurized air, directing it sequentially through passages to the five cylinders of the mtor, and receiving exhaust air from the cylinders and exhausting it to atmosphere. A rotary valve is mounted at the upper end of the air motor and the motor base is provided with internal passages that are adapted to deliver oil to bearings in which the rotary valve is mounted. A tubular conduit is arranged to receive pressurized air from one of the air passages and deliver it to a venturi nozzle that is located in the lower end of one of the internal oil passages adjacent the oil sump of the motor. The nozzle is effective to draw oil through from the sump and direct it into the internal passages for delivery to the bearings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of an air motor adapted to utilize the lubricating system of the present invention.

FIG. 2 is an enlarged vertical section taken along lines 22 of FIG. 1.

FIG. 3 is an enlarged vertical section taken along lines 3-3 of FIG. 1.

FIG. 4 is a fragmentary horizontal section taken along lines 4-4 of FIG. 3, with parts broken away.

FIG. 5 is an enlarged view of a portion of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the top view of FIG. I, the reference numeral indicates an air motor having a generally cylindrical vertical body 12. At five equally-spaced-locations around its periphery, the body is provided with radiallyoutwardly projecting sections 14, each of which receives a cylinder assembly (FIG. 2). Each cylinder assembly is bolted in sealing relation on the flat outer face of the associated mounting section 14, and includes a passage 17 that communicates at one end with a passage 19 in the body 12 and, at the other end, with a cylindrical opening 21 in a cylinder 22 that projects radially inwardly toward the axis of the air motor.

Each cylinder 22 receives a piston 23 whose connecting rod 24 is rotatably mounted at its inner end on a pin 25 carried in a throw of-a crankshaft 26. The crankshaft is journaled at its lower end in a ball bearing unit 27 carried by a closure plate 28 that is secured in sealing relation across the lower opening of the body 12. At its upper end, the crankshaft is journaled in a bearing unit 30 carried by the body 12.

A valve housing 35, which is secured in sealing relation on theupper surface of the body 12, has an inner depending cylindrical sleeve 36 that fits in a cylindrical opening in the body and provides five passages 37 (one only being shown) each of which is in communication with one of the five passages 19 in the body. The housing 35 has a cylindrical inner opening 38 that receives a cylindrical sleeve valve 40 which has reduced cylindrical portions 40a and 40b at its upper and lower ends that are rotatably journaled in ball bearing units 42 and 43, respectively. At its extreme lower end the valve 40 is provided with a depending, generally rectangular tang 44 that extends into a transverse slot 45 provided in the upper end of the crankshaft. The valve housing 35 has two

internal chambers

48 and 49, chamber 48 being in communication at the exterior of the housing with a source of pressurized air, and chamber 49 communicating with the atmosphere to provide an exhaust outlet. These chambers communicate by means of passages (not shown) and through a plurality of side

ports including ports

50 and 51 with the interior of the sleeve valve 40. Other ports, such as port 52, communicate with the passages 19 in the air motor body 12. Also, the valve has vertically extending walls (not shown) which divide the interior of the valve into longitudinal passages that communicate with certain of the ports. A cover plate 53 is bolted to the housing 35 to retain the valve in the housing. The valve housing 35 and the sleeve valve 40 are disclosed in detail in the copending application of Dickinson, Ser. No. 149,310, which was filed on June 2, 1971 and is assigned to the assignee of the present application and which has issued as U.S. Pat. No. 3,730,054. Reference may be had to the Dickinson application for a description of the structure and operation of the valve and valve housing. It will be understood that, when the crankshaft rotates, it rotates the sleeve valve, thereby causing pressurized air to be forced down each passage 19 into the associated cylinder 21 to actuate the piston. Subsequently, the passage is connected to exhaust chamber 49.

The present invention is particularly concerned with an improved lubricating system for delivering lubricating oil to the bearing units 42 and 43 and, for this purpose, one of the passages 19 is provided with a fitting 55 (FIG. 2) that is connected to a conduit 56 (FIG. 3) for subjecting the conduit 56 to the pressurized air in the passage 19. At its lower end, the conduit 56 is connected to a right angle fitting 58 that carries a nipple 59 which is also threaded into a tapped opening 60 in the lower end of the wall 61 of the body 12 of the motor. The opening 60 communicates with a tapped opening 62 formed in the wall which receives a plug 63 at one end and the base 64 of a nozzle 65 at the other end. As seen in FIG. 5, the nozzle section opens into a vertical passage 67 formed in the wall of the body. A passage 69 is formed in the wall 61 at a point between the discharge end of the nozzle and the base 64 of the nozzle. The lower end of the motor body and the closure plate 28 form a sump in which lubricating oil is disposed, with the upper level of the oil above the level of the passage 69. Accordingly, when pressurized air is directed upwardly out of the nozzle, it produces an aspirating action that draws oil out of the sump and directs it upwardly in the vertical passage 67.

Referring to FIG. 3, it will be noted that the passage 67 communicates with a horizontal passage 71 in the body. The passage 71 extends radially inwardly toward the axis of the motor and, at its inner end, it communicates with a port 72 in the depending sleeve portion 36 of the valve housing 35. Since the bearing unit 43 is disposed immediately adjacent the port 72 and at a slightly lower elevation, lubricating oil will be directed onto the bearing. An annular recess 74 is formed in the body at the inner end of passage 71 and this recess provides an annular reservoir from which oil is received by other ports (not shown) that are identical to port 72 and are arranged to direct oil onto the bearing 43 at a plurality of spaced points around the upper surface of the bearing.

A vertical passage 75 extends upwardly from a point adjacent the inner end of horizontal passage 71. This passage 75 includes a tapped portion 76 that is in alignment with

passages

77 and 78 in the valve housing 35 and in the retainer plate 53 respectively. The lower end of vertical passage 75 is provided with a reduced diameter section 79 that opens into the horizontal passage 71. A capscrew 80 extends down through the aligned

passages

77 and 78 and is threaded into the tapped opening 76. The threaded portion of capscrew 80 has four elongated slots 81 cut therein, and these slots are effective to permit passage of oil upwardly to an annular zone 82 between the inner wall of the passage 77 and the outer surface of the capscrew 80. An upwardly extending passage 83 communicates at its lower end with the annular zone 82 and at its upper end with an annular space 84 at the underside of the bearing 42.

In operation, each time a blast of pressurized air is directed through the passage 19 (FIG. 2) toward the cylinder, it is also directed through conduit 56 and nozzle 65 into the passage 67. Oil is drawn from the sump and impelled through the

passages

67, 72 and 75 to the openings adjacent the bearings 42 and 43 and then into the bearings through the adjacent ports and passages. Excess oil from bearing 43 flows down onto bearing 30 and other parts associated with the crankshaft 26.

In a typical installation section 85 (FIG. at the upper end of the nozzle 65 was 0.0312 inches in diameter, section 86 was 0.0935 inches in diameter, and passage 69 leading into the sump was 0.125 inches in diameter.

From the foregoing discussion it will be evident that the present invention provides an effective lubricating system which requires no moving parts and is selfcleaning in that the high pressure air keeps the passages clean for good oil flow. Further, it regulates the amount of oil used since there is one pulse of high pressure air for each revolution of the crankshaft. Thus, the amount of oil circulated is a direct function of the speed of the crankshaft-if the speed increases, the oil circulation increases; if the speed decreases, the amount of oil circulated decreases. Also, the system is self-relieving. It does not require any pressure-relieving device when the air motor is shut down.

While the invention has been illustrated as an integral part of an air motor, it will be understood that the system could be used as an accessory to lubricate moving parts in equipment that uses air motors as the prime mover, in which case the apparatus forming the system l 4 will use an air bleed from an air pressure conduit or chamber of the motor.

In the appended claims the term housing will be used to indicate not only the body 12 but also the valve housing 35 and portions of the cylinder assemblies.

Having thus described the invention, what weclaim as new and desire to protect by letters patent is:

1. An air motor comprising a housing, a crankshaft in said housing, a plurality of power cylinders for effecting turning of said crankshaft, at least one bearing in said housing, means defining air passages for delivering pressurized air to said cylinders, and lubricating means responsive to the pressure of air in one of said air delivery passages for directing oil through said system to said bearing, said lubricating means comprising lubrication passages formed in said housing leading to said bearing, means defining a lubricating oil reservoir in the lower portion near the lower end thereof having a connecting passage communicating said reservoir with the lower section of said lubrication passages, a conduit communicating said one air delivery passage with said lubrication passage section and including a venturi nozzle in said lower lubrication passage section, the discharge end of said nozzle being slightly above the level of said connecting passage, whereby pressurized air discharged from said nozzle will draw oil through said connecting passage and entrain it for delivery to said bearing.

2. An airmotor comprising a housing having a lubricating oil reservoir, a cylinder in said housing, a piston in said cylinder, a crankshaft connected to said piston, means associated with said housing for defining an air passage arranged to direct pressurized air to said cylinder for turning said crankshaft, at least one bearing in said housing, means defining passages leading from said reservoir to said bearing, a nozzle having its discharge end adjacent the oil in said reservoir, and means for bleeding air from said air passage and directing it through said nozzle and into the passage leading to said bearing, passage of air through said nozzle being effective to draw oil from said reservoir and entrain it in an airstream for delivery to said bearing.

3. In an airmotor having a lubricating oil reservoir, at least one piston and cylinder unit for turning a crankshaft, at least one bearing, and means including an air passage for directing a blast of air under pressure to said cylinder to actuate said piston to turn said crankshaft, the improvement which comprises lubricating oil passages communicating said reservoir with said bearing, and lubricating means for directing a portion of said blast of air into said oil passages in a direction toward said bearing for moving oil to said bearing.

4. The airmotor of claim 3 wherein said lubricating means comprises a venturi nozzle in said oil passages, a conduit communicating with said air passage for receiving pressurized air therefrom and delivering it to said venturi nozzle, passage of pressurized air through said nozzle being effective to draw oil from said reservoir and entrain it in air currents moving to said bearing.