ENTRAINEMENT A ROUES D'ENGRENAGE CONIQUES

BEVEL GEAR DRIVE

Abrégé anglais

ASSEMBLY WITH IMPROVED BEVEL GEAR ALIGNMENT
Abstract of the Disclosure
A bevel gear drive includes a housing having at least a
first and second opening. An end cap is fixably mounted in each
of the respective openings, sealing between the end caps and the
housing being provided by O-rings. A first shaft is rotatably
mounted in one of said end caps in a fixed longitudinal
position. A driving bevel gear is drivenly mounted around the
first shaft in specific location relative to the centerline of
the second opening, the location of the driving bevel gear being
specifically located by the thickness of a shim adjacent to the
base of the bevel gear. A second shaft is rotatably mounted at
one location in a bearing seated in the housing. A driven bevel
gear is drivenly mounted to the second shaft and is axially
located by a second shim between the bearing and base of the
driven gear. The specific location of the driven gear relative
to the first opening is determined by a shim thickness. The
second shaft is also rotatably supported at a second location
and the support includes means of maintaining the longitudinal
placement of the driven gear.

Revendications

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:
1. In a bevel gear assembly having an enclosure housing
with at least a first and second opening, first and second end
caps fixably mounted to said housing over respective ones of
said openings, a first shaft having a first bevel gear drivingly
mounted therearound, said first shaft being rotatably mounted in
said housing such that said first bevel gear is located therein
and having a portion of said first shaft extending through and
rotatably supported in said first end cap, and a second shaft
having a second bevel gear drivingly mounted therearound, said
second shaft being rotatably mounted in said second end cap and
having said second bevel gear drivingly mounted therearound
located in said housing in constant mesh with said first bevel
gear, wherein the improvement comprises;
first means for restraining longitudinal motion of said
first bevel gear and positively locating said bevel gear
relative to said housing including,
said housing having a formed first bearing seat,
a first bearing seatably received in said first bearing
seat, a portion of said first shaft journalled in said first
bearing, a first shim placed around said first shaft and
abutting to said first bearing, said first bevel gear being
drivingly mounted to said first shaft longitudinally locating
said shim between said first bearing and said first bevel gear,
and a snap ring fixably mounted around said first shaft abutting
to a portion of said first bevel gear:
said first end cap including a hole therethrough, a second
bearing seat formed central to a portion of said hole, a second
bearing mounted in said second bearing seat, a load ring
sandwiched in said second bearing seat abutting to said second
bearing such that said load ring is placed in compression by
said second bearing and a second snap ring fixably mounted to
said first shaft abutting to said second bearing to restrain
independent longitudinal motion of said second bearing whereby
said reaction loading of said load ring on said second bearing
acting through said second snap ring causes said first bevel
gear to maintain a fixed longitudinal location relative to said
housing predicated on the thickness of said first shim.
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2. In a bevel gear assembly as claimed in claim 1 further
comprising means of selectively setting the compression load of
said load ring including a second shim sandwiched between said
housing and said first end cap, said second shim thickness to be
within the deflection range of said load ring.
3. In a bevel assembly as claimed in claim 1 or 2, wherein
said second end cap is fixably and detachably mounted to said
housing in said second opening and having an elongated
cylindrical opening extending through said second end cap, a
third bearing assembly seated in said opening of said second end
cap; said second shaft having said second bevel gear drivingly
mounted thereto at one end internal to said housing, a torque
nut, a washer, said torque nut being fixably and adjustably
mounted to one end of said second shaft having said washer
abutting a base portion of said second bevel gear, said bevel
gear base portion being received in and abuts a portion of said
third bearing assembly, and a third shim longitudinally
sandwiched between said second bevel gear and said third
bearing, whereby the thickness of said third shim effects the
longitudinal location of said second bearing and whereby
selecting appropriate thickness of said first and third shim
allows optimum cooperative positioning of said first and second
bevel gears relative to said housing.
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Description

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1ASSEMBLY WITH IMPROVED BEVEL GEAR ALIGNMENT
Background of the Invention
This invention relates to bevel gear drive assemblies. In a
bevel gear drive assembly, it is customary in some applica-tions
for a housing to contain a plurality of bevel gears in
cooperative communication partially submerged in a lubrication
oil. End caps are provided to enable access to the interior of
the housing to facilitate assembly and repair of the bevel gear
drive assembly.
lOA bevel gear drive assembly is susceptible to wear
necessitating repair of the drive assembly. And, since the
drive assembly is generally employed as an integral part of an
overall power train, repair of the drive assembly can represent
a not insubstantial amount of system downtime. Therefore,
decreasing the frequency of needed repair or replacement of the
drive assembly inevitably represents a decrease in system
downtime representing economic benefit.
The wear characteristic of the housed bevel gears is
influenced substantially by the relative alignment of the meshed
bevel gears. It is customary to fixably mount the bevel gears
on a respective shaft, the shafts being rotatably supported
within the housing. The shafts are generally rotatably
supported at one of the support locations by a respective end
cap. It is customary to provide compressible gaskets a~
critical locations such that the bevel gear loca~ion can be
indexed by torquing down the respective end caps to the
housingO The compressible gaskets also function as seals.
Over time, the gasket recedes allowing the respective shafts
to develop end play. As a result of shaft end play, the
re~ulting bevel gear play decreases the gear lift. Further
receding and weathering of the gaskets promotes leakage of
lubricating fluid from the housingl requiring frequent
replenishment.
Summary of the ~Invention
It is therefore an objective of the present invention to
present a bevel gear drive assembly which has improved bevel
gear alignment characteristics. It is a further objective of
the present invention to present a bevel gear drive assembly
which does not employ compressible gaskets.
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1 The bevel gear drive assembly includes a housing rotatably
supporting a first shaft transverse~y therein. The first shaft
is rotatably supported at one end in the housing by a
conventional bearing. A first bevel gear is keyed or splined to
the first shaft in fixed location relative to the housingO The
mounting arrangement of the first shaft and first bevel gear
within the housing fixab]y locatQs the f;,rst bevel gear position
relative ~o the housing. A first end cap is bolted to the
housing and rotatably supports another portion of s~id first
shaft within a bearing assembly. A load ring is positioned
within the first end cap bearing seflt such that the shaft wi~1
experience zero end play. An O-ring seal and metallic shim are
placed between a respective portion of the end cap and housing
for sealing.
A second shaft is rotatably supported in a second end cap
fixably mounted to the housing such that the second shaft is
oriented generally perpendicular to the first shaft. Sealing
between the second end cap and the housing employs a sealing O-
ring sea~. ~ second bevel gear is keyed or splined to the
second shaft at one end in fixed location. The second bevel
gear is in constant mesh with the first beve] gear.
Brief Description of the Drawing
FIG. 1 is a sectioned elevated view of a bevel gear assembly
in accordance with the present inventionO
Description o the_Preferred Embodiment
Referring t,o the FIG. 1, a bevel gear assembly, generally
indicated as 11, includes a housing 13 having a plurality of
channeled openings 17, 19 and 21. Openings 17 and 19 are
concentric along centerline ~ in opposite walls of housing 13.
'30 Opening 21, is located in the housing wall to have a centerline
extension generally perpendicular to the concentric centerline
of openings l7 and 19.
Within opening 17, a bearing seat 23 is formed in housing
13. Pressed within bearing seat 23 is a conventional bearing
assembly 25. A first shaft 27 journeys through the opening 19
having a portion received in bearing assembly 25. The shaft 27
may journey beyon~ bearing assembly 25 as indicated in figure 1
in phantomO Further, opening 17 need not extend entirely
through the housing 13 when the shaft ~7 is not required to
journey beyond the housing 13.
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1 A shim 29 is placed around the shaft 27 abutting to the
bearing assembly 25 within housing 13. ~ first bevel gear 31 is
mounted within the ho~sing 13 abutting to shim 29 around and
keyed to shaft 27 at ~3. The shim 29 effects the location oF
bevel gear ~, ire., the location of bevel gear 31 relative to
the housing may be adjusted by the selection of the shim 29
thickness. A snap ring ~ is received in an annular reces.s ~6
around shaft 27 to restrain longitudinal motion of bevel gear ~]
in a conventional manner. The mounting o~ shaft 27 and bevel
gear 31 fixably locates or posi'cions the bevel gear 3~ relative
to the housing 13.
An end cap, generally indicated as ~7, is received within
opening 19 around another portion of shaft 27. The end C3p 37
has a hole 39 therein through which the shaft 27 journeys.
Within the hole 39 is formed a bearing seat 41. A conventional
bearing assembly 43 is pressed into bearinq seat dl following a
load ring 72 to rotatably support shaft 27. A snap ring 45 is
received by the sha~t 27 in a conventional manner abutting to
bearing assembly 43. The end cap 37 has a flanged portion 48
which is fixably mounted to the housing 1~ by a plurali~y of
bolts 51 in a conventional manner. An O-ring seal 47 is seated
within an annular recess 46 in end cap 37 and abuts the housin~
portion defining opening 19. A metal shim 49 is sandwiched
between the housing 13 and the end cap ~ange 48. A sealing
cover 53 i5 placed in openins 17 and a sealing cover 55 is
placed in hole 39. ~t is noted that the thickness of shim 49 is
set by the deflection specification of the load ring 72. The
load ring 72 is thereby able to compensate for al~ manufacturing
tolerances and achieve zero end play of shaft 27. ~s a result,
the bevel gear 31 is in a fixed location relative to the housing
13.
Within opening 21 is located an end cap 57. A sealing ring
59 is seated within an annular recess 60 between the end cap 57
and housing portion deining the opening 21. The end cap 57 has
a channeled opening 63 with a first bearing seat 65 formed
within opening 63. A shaf'c 67 journeys into the opening 63
having a threaded end port;on 68 located inward to the housing.
I'he shaft 67 carries a second bevel gear 69 keyed to one end of
the shaft 67 at 71. A torque nut 7~ preceded by a washer
abutting to one end of bevel gear 69 is threadably mounted to
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l shaft portion on 68. The base 74 of bevel gear 69 is pressed
mounted into a bearing assembly 75 residing in bearing seat 65.
A shim 76 is placed between the bearing assembly 75 and bevel
gear 69 around the base 74 locating the bevel gear 69. The
bevel gear 69 is in constant mesh with the first bevel gear 31.
A second conventional bearing assembly 77 rotatably supports the
shaft 67 at a location along shaft 67 within the end cap opening
63. The bearing assembly 77 i5 restrained within opening 63
from longitudinal motion to the 1eft by snap ring 79 set ln end
cap 57 within openin~ 63 in an annular recess 80 and to the
right by snap ring 81 set within an annular recess 80 and to the
right by snap ring 81 set within an annular recess 82 formed in
shaft 67 in a conventional manner. ~ sealing cover 83 is press
mounted in the mouth of opening 63 around shaft 67.
Lt is by now appreciated by one reasonably skilled in the
art, that the present invention allows for the achievement of
zero end play of the shaft 27. That is, the cross-sectional
length of the load ring 72 exceeds the space requirements such
that torquing of the end cap screws 51 places the load ring 72
2~ in compression, thereby compensating for manufacturing tolerance
buildup. The shim 4~ allows the space reguirements of the load
rinq to ~e adjusted within the compression range of the load
ring 72. It is further appreciated that by the selection of the
shim thickness for shims 29 and 76, the optimum position
relationship between bevel gears 31 and 69 can be achieved. It
is noted the absence of any compressible gasket allows the
position relationship between bevel gears 31 and 69 to be
enduring, And, further, the absence of compressible gaskets
removes a lubrication leakage median from the bevel gear
assembly ll~ sea1ing between the end caps and housing being
facilitated by seated O-rings.
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