US3350985A

US3350985A - High speed rotary hydraulic motor

Info

Publication number: US3350985A
Application number: US435471A
Authority: US
Inventors: Edward L Ackley
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-02-26
Filing date: 1965-02-26
Publication date: 1967-11-07
Anticipated expiration: 1984-11-07

Description

Nov. 7, 1967 E. 1.. ACKLEY 3,350,935

HIGH SPEED ROTARY HYDRAULIC MOTOR Filed Feb. 26, 1965 Edward Lackl INVENTOR.

3 BY 'y United States Patent ()fl" 3,350,985 Patented Nov. 7, 1967 3,350,985 HIGH SPEED ROTARY HYDRAULIC MOTOR Edward L. Ackley, 1916 SE. 50th, Portland, Greg. 97215 Filed Feb. 26, 1965, Ser. No. 435,471 2 Claims. (Cl. Ell-87) ABSTRACT OF THE DISCLOSURE A cylindrical case houses recessed front, rear and central core segments supporting a drive shaft. One of a pair of gears in the central segment is secured to the drive shaft, and hydraulic fluid under pressure is conveyed to and from the gears through passageways in the front seg ment and conduits in a handle connected to the case. Bearings and seals are associated with the segments and drive shaft, and the outer end of the latter supports a rotary tool.

This invention relates to high speed rotary hydraulic motors.

Although various types of rotary hydraulic motors are we1l-known, need exists for an improved motor of this classwhich may be applied satisfactorily to heavy duty uses such as the operation of high speed rotary pruning saws.

.It accordingly is the general purpose of the present invention to provide a heavy duty, high speed, hydraulic motor:

( 1) which operates at exceptionally high speed, for example, at speeds of in exces of 15,000 r.p.m.;

(2) which does not heat excessively, even when operated In the drawings:

FIG. 1 is a longitudinal sectional view of the rotary hydraulic motor of my invention;

FIGS. 2 .and 3 are front and back elevations of the motor, respectively, FIG. 2 being partly in section;

FIG. 4 is a fragmentary, detail sectional view taken along line 4-4 of FIG. 3 and illustrating the manner of assembling the motor;

FIG. 5 is a fragmentary, sectional view taken along line 55 of FIG. 1 and illustrating a novel gear drive which may be employed in the motor; and

FIG. 6 is an enlarged fragmentary view illustrating seal means employed in the motors of my invention to seal the motor against leakage of high pressure hydraulic fluid.

The motor of my invention is illustrated in the drawings in its application to a rotary pruning saw although it is applicable also to Inanyother uses. As shown particularly in FIGS. 1, 2, and 3, the saw .ishoused in a case 10 comprising a short, hollow cylinder open on both ends and made of stout metal.

The case is provided with a connector 12 comprising a short pipe which extends at right angles to the case communicating with the interior thereof. It telescopes over a hollow handle 14 which in a pruning saw application may be twelve or fifteen feet long.

The handle, in turn, houses hydraulic fluid conduits 16, 18, the one being for the transmission of input fluid under pressure and the other for the transmission of exhaust fluid. These may be included in an hydraulic circuit designed to provide hydraulic fluid under pressure to the motor as required for its operation.

Case 10 houses a transversely segmental core which in the illustrated form of the invention includes three longitudinally recessed segments: a rear segment 20, a central segment 22, and a front segment 24.

Front segment 24 is formed with first connecting passageways 26, 28 and second connecting passageways 30,.

32 which communicate, respectively, with input and

exhaust conduits

16, 18 by means of which hydraulic fluid is supplied to and exhausted from the driving elements of the motor.

A seal ring 34 and a seal ring 36 are associated, respectively, with passageways 26 and 30 to prevent the escape of fluid.

Securing means are provided for securing the core segments to each other and for securing the assembled core.

in the case. It is a particular feature of the invention that the securing means used permit easy disassembly and assembly of the motor as required for its servicing and repair.

To achieve this purpose, there are provided a plurality.

of cap screws 40 which penetrate

segments

20 and 22 and which are threaded into front segment 24, being arranged 44 which are insertable in registering apertures in thesegments when the segments are arranged in proper relation for coupling them by. means of

screws

40, 42.

The recess in central core segment 22 provides a chamber 48, FIG. 5. Thischamber is sealed off by means of

seal rings

50, 52.

Meshing

hydraulic gears

54, 56 work in chamber 48. As will be noted from FIG. 5, the teeth of these gears are unique in that they extend radially from the gear base and are tapered uniformly toward an outer terminal apex.

At no place in their contour are the gear teeth undercut.

As result, they mesh smoothly without trapping oil during any phase of their operation. This in turn assists in keeping the heat generated by operation of the motor at a minimum. It also assists in reducing the operating vibration.

Hydraulic gear 54 is keyed to a shaft 58, the ends of which are journaled in needle bearings 59.

Hydraulic gear 56 is keyed or otherwise fixed to the drive shaft of the motor, indicated generally at 60. Shaft 60 is free to move longitudinally within limits thereby avoiding applying a thrust force against the gear, with consequent development of heat.

Shaft 60 is elongated, extending completely through case in an axial direction. It is stepped in its longitudinal configuration being provided with an inner section 62 of relatively restricted diameter and an outer section 64 of relatively substantially enlarged diameter, the two sections being separated by an annular shoulder 66.

Inner section 62 of shaft 60 mounts gear 56. It is journaled in suitable bearings such as needle bearings 68 positioned one on each side of the gear.

As is apparent in FIG. 1, the outer end of outer enlarged section 64 of drive shaft 60 extends completely beyond the plane of case 10 and mounts the appliance to be driven by the motor. Thus the outer end of the shaft may be threaded and may mount a saw blade 70 between clamps 72. Nut 74 threaded on the end of the shaft supplies the clamping pressure required releasably to mount the saw blade.

It is a particular feature of the invention that shaft 64) is supported in bearing means which braces the shaft against thrust in both directions, as Well as against radial stresses, thereby relieving wearing strain which otherwise would be exerted on the motor gears and also reducing the tendency of the motor to develop heat at high operating speeds. To this end there is provided a husky bearing 80 which may comprise an assembly of one or more ball or roller bearings arranged end to end with the inner end of the bearing abutting against shoulder 66 of the shaft.

Retaining means are provided for retaining bearing 80 in place while at the same time resisting shaft thrust in both directions.

The retaining means include a first snap ring 82 seated in the recess in front core segment 24 and bearing against the outer margin of bearing 80. This ring takes the thrust of the drive shaft when the thrust is exerted outwardly, or to the right as viewed in FIG. 1.

Seated on the outer end of enlarged section 64 of shaft 60 is a second retaining ring 84. This also is adjacent the outer end of bearing 80. It takes the thrust of the drive shaft when the thrust is exerted inwardly, i.e. toward the left as viewed in FIG. 1.

It thus will be noted that bearing 80, which journals the enlarged section of the drive shaft, takes the major portion of the working stresses occurring during operation of the motor, whether the stresses occur radially or endwise. This in turn saves stress and wear on the relatively sensitive gears of the motor.

Another particular feature of the invention is the provision of novel seal means along the drive shaft for preventing the escape of high pressure hydraulic fluid from the gear chamber. The construction of the seal means is shown in FIGS. 1 and 6.

A seal retainer 90 is seated in the longitudinal recess in core segment 24, being. arranged coaxially with the inner restricted section 62 of the drive shaft 60. It is located inside of shoulder 66 and is retained in place by means of a snap ring 92 seated in core segment 24. The outer peripheral surface of seal retainer 90 is recessed to accommodate a static seal O-ring 94.

Retainer 90 houses a seal member 96 which likewise is coaxial with section 62 of shaft 60 against which it bears. Its outer peripheral surface is recessed to accommodate a static seal O-ring 98. Its inner peripheral surface is recessed to accommodate a quad-ring 100.

The materials of which the sealing elements are composed is of importance in determining the efficiency and service life of the seal. It is one of the objects of my invention to fabricate shaft section 62, seal 96 and quadring 100 of relative materials having friction characteristics such that the friction coefficient of quad-ring 100 with reference to shaft section 62 will be greater than the friction coefficient of the quad-ring with reference to seal 96.

For example, where shaft section 62 is of metal, quadring 100 of rubber and seal 96 of molybdenum sulfidelubricated nylon, the frictional coefiicient of the rubber quad-ring with reference to the metal shaft section will be greater than its frictional coefficient with respect to the lubricated nylon seal ring.

As a consequence, during high speed operation of the motor, quad-ring 160 will rotate within the recess in which it is housed to an extent sufficient to relieve the stress and prevent slippage of O-ring 98, thus preserving the static seal afforded by the latter ring. This feature not only improves the seal but also lengthens the service life of the sealing member substantially.

It thus will be seen that the construction of the motor herein described is such as to achieve the various objects of the invention.

The motor may be assembled and disassembled rapidly and easily simply by inserting or removing

screws

40 and 32. During high speed operation of the motor the pointed teeth of

gears

54, 56 mesh cleanly without trapping oil, thereby reducing friction and heat generation.

Large bearing on the enlarged portion of stepped shaft 60 takes the major portion of the developed stress during heavy duty service, including both the radial stress and the thrust stress in both directions. Wear on

gears

54, 56 as well as on bearings 59, 68 thus is minimized.

In addition, the efficiency of the hydraulic fluid seal is greatly improved first, by locating it on section 62 of the drive shaft which has a peripheral speed substantially less than that of enlarged section 64, and secondly by providing the special inner seal arrangement illustrated in FIG. 6 above described which prevents wear of the sealing elements.

The motor accordingly is characterized by a long and efficient service life even when applied to the operation of high speed, heavy duty equipment such as rotary pruning saws.

It is to be understood that the form of my invention herein shown and described is to be taken as preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. A high speed rotary hydraulic motor comprising (a) a cylindrical case open at both ends,

(b) a handle mounting the case,

(0) hydraulic fluid input and exhaust conduits mounted on the handle,

(d) in the case a transversely segmental core comprising recessed front, back and central segments, the front segment having hydraulic fluid input and exhaust passageways communicating the input and exhaust conduits with the recessed central segment,

(e) securing means securing the core segments together and securing the core in the case,

(f) a pair of meshing hydraulic motor gears journaled in the core and arranged in the recessed central'segment to be driven by hydraulic fluid under pressure circulating in the input and exhaust conduits and passageways,

(g) a motor drive shaft extending in the axial direction of the case and having an outer end portion extending outward from the front core segment and having tool mounting means thereon and an inner end por- 2. The motor of claim 1 wherein the teeth of the hy-. draulic motor gears are arranged radially at spaced intervals about the periphery of the gear, each tooth beingi 5 6 uniformly tapered in a radial direction to a point at its 2,938,438 5/1960 Hamilton 91-87 X apex. 3,076,684 2/1963 Todtenhaupt 30836.3 X

References Cited UNITED STATES PATENTS FOREIGN PATENTS 1,769,030 7/1930 Lassen 308-363 5 572,631 3/1933 Germany- 2,391,577 12/1945 Larson 103--126 X 2,466,972 4/1949 solmer 91 87 X MARTIN P. SCHWADRON, Pnmary Exammer.

2,632,424 3/1953 Solmer 91-87 X G. N. BAUM, Assistant Examiner.

Claims

1. A HIGH SPEED ROTARY HYDRAULIC MOTOR COMPRISING (A) A CYLINDRICAL CASE OPEN AT BOTH ENDS, (B) A HANDLE MOUNTING THE CASE, (C) HYDRAULIC FLUID INPUT AND EXHAUST CONDUITS MOUNTED ON THE HANDLE, (D) IN THE CASE A TRANSVERSELY SEGMENTAL CORE COMPRISING RECESSED FRONT, BACK AND CENTRAL SEGMENTS, THE FRONT SEGMENT HAVING HYDRAULIC FLUID INPUT AND EXHAUST PASSAGEWAYS COMMUNICATING THE INPUT AND EXHAUST CONDUITS WITH THE RECESSED CENTRAL SEGMENT (E) SECURING MEANS SECURING THE CORE SEGMENTS TOGETHER AND SECURING THE CORE IN THE CASE, (F) A PAIR OF MESHING HYDRAULIC MOTOR GEARS JOURNALED IN THE CORE AND ARRANGED IN THE RECESSED CENTRAL SEGMENT TO BE DRIVEN BY HYDRAULIC FLUID UNDER PRESSURE CIRCULATING IN THE INPUT AND EXHAUST CONDUITS AND PASSAGEWAYS, (G) A MOTOR DRIVE SHAFT EXTENDING IN THE AXIAL DIRECTION OF THE CASE AND HAVING AN OUTER END PORTION EXTENDING OUTWARD FROM THE FRONT CORE SEGMENT AND HAVING TOOL MOUNTING MEANS THEREON AND AN INNER END PORTION SECURED TO ONE OF THE GEARS,