US3546505A - Vibrator motor with self-container lubricant circulator - Google Patents

Description

Dec; 8 1970 J. M. MORRIS 3,546,505

VIBRATOR MOTOR WITH SELF-CONTAINER LUBRICANT CIRCULATOR Filed May 6, 1968 3 She ts-Sheet 1 INVENTOR. JOHN M. MORRIS ATTORNEYS J. M. MORRIS VIBRATOR MOTOR WITH SELF-CONTAINER LUBRICANT CIRCULATOR Filed May 6; 1968 3 Sheets-Sheet 2 FIGS INVENTOR.

JOHN M. MORRIS BYW4M? ATTORNEYS Dec. 8, 1970 J R S 3,546,505

VIBRATOR MOTOR WITH SELF-CONTAINER LUBRICANT CIRCULATOR Filed May e; 1968 5 Sheets-Sheet 5 INVENTOR. JOH N M'. MORRIS ATTORNEYS United States Patent US. Cl. 31081 8 Claims ABSTRACT OF THE DISCLOSURE This invention relates to motors for driving vibratory apparatus and more particularly to an arrangement in which eccentric weights carried on the motor shaft serve as an impeller of a centrifugal pump for pumping lubricant contained in a housing surrounding the weights through a circuit that includes ball or roller bearings for the purpose of lubricating such bearings. The invention further employs connecting means, when eccentric weights are mounted at each end of the motor, for equalizing the quantity of lubricating fluid contained in each of the eccentric weight housings.

BACKGROUND OF THE INVENTION It is common practice to mount the eccentric weights for driving vibratory apparatus directly on the motor shaft and to mount the motor on the member to be vibrated. The size of equipment that can be built according to this design is limited by the problem of lubricating the bearings carrying the eccentric weighted shaft. Providing external oil lubrication for the bearings, as is done in large stationary apparatus, is diflicult because of the relative motion between the motor frame and any stationary housing surrounding the equipment.

SUMMARY OF THE INVENTION The principal object of this invention is to provide a self-contained lubricant circulation system for lubricating the bearings of a vibrating motor.

An ancillary object of the invention is to subject the oil or other lubricant to a centrifugal field that is large compared to the acceleration of the motor in its vibratory path to reduce or completely eliminate any frothing of the oil prior to flowing into the passages leading to the bearings.

According to the invention the vibratory motor is provided with a sealed end bell serving as a housing for an eccentric weight, as a chamber for containing a supply of lubricating fluid, and as the stationary member of a centrifugal pump. The eccentric weight serves as the impeller of the pump and one or more passages are provided in the end bell assembly leading from the pressurized region of the pump to a bearing supporting the shaft.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred form of the invention is illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a side elevation, in simple schematic form, of a vibratory screen, agitator, or similar device illustrating a work member to be vibrated by a motor constructed according to the invention.

FIG. 2 is a side elevation with parts broken away to show a preferred form of construction of a self-lubricating motor for a vibratory apparatus.

FIG. 3 is a vertical section taken substantially along the line 33 of FIG. 2.

FIG. 4 is a vertical section showing an alternative form of construction of the end bell that provides the fluid reservoir and housing of the pump.

3,546,505 Patented Dec. 8, 1970 FIG. 5 is a vertical section transverse to the motor axis showing an alternative form of eccentric weight and cooperating passage entrance to increase the output pressure of the pump.

FIG. 6 is a side elevation, with parts broken away, showing a modified arrangement of the path of flow of the lubricating fluid.

These specific figures and the accompanying description are intended merely to illustrate the invention and not to impose limitations on its scope.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A vibratory work member 1, which may be a vibratory screen, a vibratory hopper, a vibratory feeder or any vibrating body is supported by means of isolation springs 2 from an overhead support indicated by beam fragments 3. A vibratory motor 4 constructed according to the invention is rigidly attached to the work member 1 and is connected through suitable leads, not shown, to a source of electrical power. Squirrel cage induction motors are commonly employed for this purpose since they can be rigidly constructed so as to be immune from the effects of the vibratory motion to which they are subjected.

The motor 4 is shown in greater detail in FIG. 2. As there shown it comprises a stator 5 that includes an outer shell or frame 6 which may be provided with cooling fins, a field tructure 7 including the primary windings and a squirrel cage rotor s supported on a rotor shaft 9.

The motor 4 is provided with at least one end bell 10 that includes a heavy wall 11 in which a ball or roller bearing 12 journaling the shaft 9 is mounted. The end bell 10 also includes a cylindrical section or portion 13 terminating in an outwardly directed lip 14 to which an end plate 15 is attached. A first eccentric weight 16 is constructed integrally with a hub 17 mounted on and keyed to the motor shaft 9. A second eccentric weight 18 is adjustably mounted on the hub 17 so that by varying its angular relation to the first eccentric weight 16 the total effective unbalance may be readily adjusted in magnitude.

The heavy wall 11 of the end bell 10, the cylindrical section 13, and the cover plate 15 form an annular chamber that serves as a reservoir for a supply of lubricating fluid for the bearing 12. This chamber, at least in its radially outer portions, has a size and shape that corresponds to the space swept through by the eccentric weights 16 and 18 as they are revolved by rotation of the shaft 9. The inner wall or surface of the cylindrical section 13 is smooth so that lubricating fluid in the chamber may be swept around the periphery by the eccentric weights. It has been observed in this type of construction that the lubricating fluid distributes itself in a substantially uniform annular layer in the chamber, the layer being slightly thicker on the leading side of the eccentric weights.

The rotary motion of the lubricating fluid developes a pressure that corresponds to the radius of the cylindrical section 13, the angular velocity of the eccentric weights, the radial thickness of the annular layer of fluid, and the density of the lubricating fluid. Theoretically, if the cylindrical section has a radius of eighteen inches, the angular veiocity is approximately 700 revolutions per minute and the thickness of the annular body of lubricating fluid is about a half inch, the pressure corresponds to a column of the fluid approximately 8 to 10 feet in height.

Advantage is taken of this pressure developed in the lubricating fluid to cause it to flow through a duct 20 that leads from a radially outer portion of the annular chamber inwardly and terminates in a distribution groove 21 formed in the outer race of the bearing 12. Passages 22 lead the oil or other lubricating fluid from the distribution groove 21 to the space between the paths of the rollers 23 of the bearing. From this space the oil or the lubricating fluid flows axially through the bearing either directly into the eccentric weight chamber or into a small chamber 24 between the wall 11 of the end bell and an oil seal 25 surrounding the shaft 9 and sealingly attached to the wall 11. A drain 26 returns the lubricating fluid collected in the chamber 24 to the eccentric weight chamber.

Referring to FIG. 3, the distribution of the lubricating fluid in the chamber when the motor is running is indicated by the annular body of fluid 27 which may have its maximum radial depth at the leading edge 28 of the eccentric weights and its minimum radial depth at the trailing edge 29.

Conventional filler plugs 30 and drain plugs 31 are provided to facilitate adding or changing lubricating fluid.

Preferably the motors for vibratory apparatus are mounted with the shafts horizontal. It occassionally happens, however, in some types of equipment, that the motor must be mounted with the shaft at an angle to the horizontal. As an additional feature, recognizing that the oil seal 25 may leak, a drain 32, FIG. 2, is provided leading from the space within the stator shell 6 into the eccentric weight chamber at the lower end of the motor. Furthermore, a connecting passage or tube 33 is provided to connect a point near the periphery of the eccentric weight chamber at one end of the motor to the corresponding point in a chamber at the other end of the motor. A similar tube 34 is arranged to interconnect radially inner points of the eccentric weight chambers to provide an equalizing passage or vent between the chambers. In operation, assuming there is a difference in the quantity of lubricating fluid in the end bells at opposite ends of the motor a differential pressure is developed between the ends of the connecting passage or tube 33 causing a flow of lubricating fluid to equalize the quantity in the two chambers. This flow is permitted without change in air pressure in the chambers by corresponding air flow through the tube 34.

A slightly different form of construction of an improved end bell and housing is shown in FIG. 4. As shown in this figure, the end bell is formed of a heavy plate suitably attached to the end of the motor stator 41. The end bell plate 40 carries a ball or roller bearing 42 that journals a motor shaft 43. An eccentric weight 44 mounted on the shaft 43 includes a hub 45 on which a second eccentric weight 46 is suitably mounted for angular adjustment relative to the weight 44. This construction differs from that previously described in that the first eccentric Weight 44 extends radially further than the second weight 46. A pan-shaped cover 47 is shaped so that at least its marginal portion corresponds in size and shape to the path or space swept by the radially outer portions of the eccentric weight 44. This portion constitutes an annular trough 48 along which the lubricating fluid is driven by the outer portion of the eccentric weight 44.

A suitable duct 49 feeds lubricating fluid from the annular trough 48 into the stator 41. The fluid then flows from the stator through the bearing 42 and into the chamber formed within the pan-shaped cover 47. If desired, a suitable partition 50 may be used to separate the hearing 42 from the interior of the motor stator 41 and regulate the flow of fluid through the bearing. This partition surrounds the motor shaft 43 without touching it and forms with the bearing a small chamber through which oil flows to the bearings 42 and back into the cocentric weight chamber to be collected in the trough 48.

In this version as in the first an interconnecting tube 52 connects a point of the annular chamber of one ed bell 48 with a similar point in the opposite end bell to provide equalization of the quantity of lubricating fluid in the eccentric weight chambers. In this case a vent or return tube is not necessary since the pressures may equalize by flow of air and oil through the bearings and the opening in the partition 50 surrounding shaft 43.

This type of end bell may be used when the motor is mounted at an angle provided the windings of the motor are provided with an insulation that is impervious to the lubricating oil. In this case the lubricating fluid fills the otherwise unoccupied space in the interior of the stator 41 and flows from such space through the bearings and into the end bells. The pressure developed at the periphery of the lower end bell and the restriction of the partition 50 is suflicient to maintain a flow from the stator through the bearings at the upper end of an inclined motor.

As a further modification, the rotor of the motor may be provided with impeller blades and additional ducts, similar to the duct 20, may be provided from the stator space to the distribution groove 21. The seal 25 may then be omitted and the oil discharged either way from bearing.

In the modification shown in FIG. 5 an eccentric weight 60 is formed so that its leading edge 61 has greater clearance from the surrounding housing wall 62 than its trailing edge 63. This difference in clearance produces a wedge or sled runner effect to build up pressure between the weight and the housing. This pressure transmits part or all of the centrifugal force of the rotating eccentric weight 60 directly to the housing 62 thus relieving the bearings of that load.

An outlet passage 64 for the lubricant (corresponding to passage 20) opens tangentially from the periphery of the housing 62 to convert the velocity head of the rotating body of lubricating fluid into pressure in the passage 64 thus tending to increase the circulation of the fluid. The combination of the pressure developed by the centrifugal force is periodically increased by the sled runner effect each time the weight 60 passes the outlet passage 64 thus still further augmenting the flow of fluid.

Each of the foregoing circulation methods returns the oil to the eccentric weight chambers near the center of the chamber. While not shown in the drawings, it is desirable to direct the returning oil into the annular rotating pool with a minimum of agitation to minimize the entrainment of air in the oil. This may be done in any of several ways. One way is to provide a disk attached to the eccentric Weights and located between the weights and the bearing, the margin or rim of the disk being of a size to dip into the annular rotating pool of oil. The marginal area should be fitted with vanes or fins to ensure rotation of the oil in the space between the disk and the motor end plate.

Another way is to provide a small diameter annular cup around the motor shaft and end of the bearing sleeve to catch the oil returning to the eccentric weight chamber. The cup is provided with a radially directed drain leading into the rotating oil pool.

In either of these arrangements the oil returning to the eccentric weight chamber is slowly accelerated to the shaft speed before flowing into the annular pool thus avoiding any splashing that occurs if the leading side of the eccentric Weight strikes the incoming stream of oil.

A still further method of returning oil to the rotating pool is to use a stationary drain from the bearing leading tangentially, in the direction of eccentric weight movement, into the rotating oil pool. In this arrangement the incoming oil is accelerated by viscous friction with the ro tating pool without impact from the eccentric weights Which would cause splashing and foaming.

The lubricating fluid, in addition to lubricating the bearings, may also be used as a heat transfer medium to trans fer heat from the stator windings and rotor of the motor to the housing. A simplified showing of such an arrangement is shown in FIG. 6. In this arrangement eccentric weights 70 drive lubricant fluid through an outlet passage 71 directed into the space between a stator 72 of the motor and an outside shell 73 of the motor. From this space the fluid may flow through gaps 74 left between stator laminations to a rotor 75 of the motor and thence in the gap along the rotor to the spaces at each end of the rotor. From these spaces the fluid flows through rotor shaft bearings 76 and into the eccentric weight chambers. The lubricating fluid is thus in contact with the outside shell of the motor and weight assembly as long as it is in the eccentric weight chambers and during the first part of its path through the motor. This provides ample time to cool the fluid prior to its passage past the stator windings and rotor and back through the rotor bearings.

In each example the motor stator and attached end bells form a sealed assembly and lubricating fluid in the assembly is pumped through a path that includes the ball or roller bearings journaling the rotor shaft.

The foregoing specific description is intended to merely illustrate the invention and not to impose limitations on the claims.

I claim:

1. In a motor for driving vibratory apparatus, in com bination, a stator, a rotor having a shaft, an end bell that closes an end of the stator, a shaft bearing mounted in the end bell, a cylindrical extension that is concentric with the shaft mounted on the end bell to form a pump chamber, an end plate included in the extension, said extension cooperating with the end bell to constitute a centrifugal pump stator, an impeller of substantial mass mounted on the motor shaft within the cylindrical extension for driving any lubricating fluid in the cylindrical extension in a circular path along the periphery of the chamber, said impeller having its center of gravity offset from the motor shaft to constitute an eccentric weight, and a duct in the end bell connecting the periphery of the cylindrical extension to the shaft bearing, whereby lubricating fluid forced to the periphery of the cylindrical extension flows to the bearing.

2. A motor assembly according to claim 1 having sealing means mounted on a wall of the chamber and sur- 6 rounding the shaft to complete the enclosure of the bearing in the chamber.

3. A motor assembly according to claim 1, in which the duct means extends from the radially outermost portion of the chamber to the bearing.

4. A motor assembly according to claim 1 in which a duct connects a radially outer portion of the chamber of one end bell with a corresponding portion of a similar end bell on the other end of the motor.

5. A motor assembly according to claim 4 having means mounted on the exterior of said chamber in noncontacting relation to said shaft for collecting lubricating fluid from said bearing and returning it to said chamber.

6. In a motor assembly according to claim 4, a drain from the interior of the stator to an end bell chamber.

7. A motor assembly according to claim 1 in which the radial clearance between at least one of the eccentric weights and the surrounding housing varies and has a maximum at the leading edge of the weight.

8. A motor assembly according to claim 1 in which the duct means leads tangentially from the chamber in the end bell.

References Cited UNITED STATES PATENTS 2,688,102 8/1954 Jackson 310-81 2,854,594 9/1958 Philipovic 31081X 2,857,535 10/1958 Kroeckel et a1 310-81 FOREIGN PATENTS 1,100,352 2/1961 Germany 31081 MILTON O. HIRSHFIELD, Primary Examiner M. O. BUDD, Assistant Examiner U.S. Cl. X.R. 31063.90

Images