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Title:
ENCLOSED GEAR DRIVE MECHANISM FOR EXCAVATORS
United States Patent 3811577
Abstract:
An excavator comprises an upper unit rotatably mounted on a tracked undercarriage. The upper unit is rotated on the undercarriage by selectively driving a swing pinion against a reaction ring gear secured to the undercarriage. An enclosure forms an annular chamber containing the swing pinion and ring gear, including radially disposed and separated compartments for assuring uniform distribution of a lubricating oil therearound when the excavator is tilted.


Inventors:
YANCEY J
Application Number:
05/238311
Publication Date:
05/21/1974
Filing Date:
03/27/1972
Assignee:
Caterpillar Tractor Co. (Peoria, IL)
Primary Class:
Other Classes:
74/467
International Classes:
B62D55/06; B66C23/84; E02F9/12; F16H57/04; (IPC1-7): B66C23/84
Field of Search:
212/67,68,69,66 74
View Patent Images:
US Patent References:
Primary Examiner:
Aegerter, Richard E.
Assistant Examiner:
Lane, Hadd
Attorney, Agent or Firm:
Phillips, Moore, Weissenberger, Lempio & Strabala
Claims:
1. A construction machine comprising

2. The invention of claim 1 wherein the teeth of said ring gear face radially inwardly towards said central axis to define portions of said

3. The invention of claim 2 wherein said wall means includes vertically spaced and horizontally disposed annular upper and lower walls extending radially inwardly towards said central axis from said ring gear and a generally vertical and annular inner sidewall spaced radially inwardly from said ring gear and disposed generally vertically between said upper

4. The invention of claim 3 wherein said upper wall is secured to said support and said lower wall is secured to said ring gear, and further including annular sealing means for effecting a fluid tight seal between

5. The invention of claim 3 further including a substantially annular U-shaped tray disposed in said annular chamber comprising contiguous

6. The invention of claim 5 wherein said tray further comprises a plurality of circumferentially spaced plates disposed in said tray to extend radially inwardly towards said central axis, between the sidewalls of said tray, to divide the tray into a plurality of individual compartments

7. The invention of claim 6 further comprising means forming at least one port through a sidewall of said tray, adjacent to said ring gear, for

8. Inner and outer annular members,

9. The invention of claim 8 wherein

10. The invention of claim 9 wherein said wall means includes vertically spaced and horizontally disposed annular upper and lower walls extending radially inwardly towards said central axis from said ring gear and a generally vertical and annular inner sidewall disposed therebetween and

11. The invention of claim 10 wherein said upper wall is secured to said outer member, said lower wall is secured to said inner member and said sidewall is integrally formed with said lower wall, and further including annular sealing means for effecting a fluid seal between said inner

12. The invention of claim 8 wherein said port is formed through a generally vertically disposed sidewall of said tray positioned closely

13. The invention of claim 8 wherein a bottom wall of said tray is disposed below said ring gear and further comprising lubricating oil retained in said chamber and compartments to at least cover lower portions of said

14. The invention of claim 8 wherein said tray is interrupted circumferentially to define an opening, said pinion gear disposed in said

15. A horizontally disposed, annular enclosure completely enclosing a gear drive mechanism and lubricating means comprising a plurality of circumferentially spaced baffle plates disposed in said enclosure to form a plurality of individual compartments therein and means communicating at least some of said compartments with said gear drive mechanism through a radially outer side of said enclosure for maintaining a substantially uniform distribution of lubricating fluid circumferentially around said enclosure when said enclosure is tilted relative to its normal horizontal

16. The invention of claim 15 wherein said gear drive mechanism comprises

Description:
BACKGROUND OF THE INVENTION

The present invention relates to an enclosed and continuously lubricated gear drive mechanism, particularly adapted for use in a hydraulic excavator. Conventional power transmissions employed in excavators include a motor-driven swing pinion which rotates against a stationary ring gear to selectively rotate an upper unit relative to a mobile undercarriage.

Such a swing pinion and associated ring gear are generally not enclosed to thus expose them to dust and other foreign matter associated with the operation of the excavator. The swing pinion is usually lubricated by applying a heavy grease thereto manually. The grease tends to entrap such dust and foreign matter to abrasively wear the gears unduly.

Prior attempts to enclose and continuously lubricate the swing pinion and associated ring gear have usually failed due to the large quantity of lubricating oil required to be carried on the excavator. Also, the excavator normally employs a swivel connection for hoses which communicate hydraulic operating fluid from the upper unit to the undercarriage. Since the swivel connection is usually mounted on the center line of the ring gear, it tends to interfere with placement of a standard housing over the gears. Furthermore, excavators frequently operate on slide slopes which would function to induce leakage of the lubricating oil at the low side of the housing.

OBJECTS OF THE INVENTION

Accordingly, an object of this invention is to provide an improved enclosure for a ring and pinion gear drive mechanism.

Another object of this invention is to provide an enclosure for a gear drive mechanism which affords a substantially dust-free operating environment for the gears.

Another object of this invention is to provide an enclosure for a gear drive mechanism which affords a substantially fluid-tight lubricant compartment around the ring and pinion gears.

Another object of this invention is to provide an enclosure for a gear drive mechanism which continuously maintains a substantially uniform distribution of the lubricant therearound when the enclosure is tilted relative to ground level.

Another object of this invention is to provide an enclosure for a gear drive mechanism which is substantially concentric with the ring gear and which utilizes the ring gear as one of its sidewalls.

Other objects and advantages of the present invention will become apparent with reference to the accompanying drawings and following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a hydraulic excavator having the enclosed gear drive mechanism of this invention employed therein.

FIG. 2 is an enlarged top plan view of the enclosed gear drive mechanism, taken on line II--II in FIG. 1, with portions broken-away for illustrative convenience.

FIGS. 3 and 4 are sections respectively taken on lines III--III and IV--IV in FIG. 2.

FIG. 5 is a fragmentary section taken on line V--V in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, an earthworking machine, such as a hydraulic excavator 10, has an upper unit 11 rotatably mounted on a mobile undercarriage 12 by a swing bearing 13. The upper unit includes a mounting ring 14 secured under a frame 15 whereas the undercarriage has a support ring 16 secured thereon. The undercarriage may be mounted on standard, laterally spaced endless tracks.

Referring to FIG. 3, swing bearing 13 includes an inner ring member 17 secured to underlying support ring 16 by bolts 18. The inner ring member is concentrically disposed about a vertically disposed central axis X thereof (FIG. 2) and within an outer ring member 19, attached to mounting ring 14 by bolts 20. The inner and outer ring members are formed with complementary raceways 21 and 22, respectively, which mount bearings means therein comprising a series of circumferentially disposed ball bearings 23 to enable relative rotary movement to occur between the ring members about common axis X (FIG. 2).

The inner ring member forms a reaction-type ring gear comprising a plurality of gear teeth 24 positioned to face radially inwardly towards such axis. Annular lip seals 25 and 26 are secured to the inner and outer ring members, respectively, and are maintained in sliding and sealing contact with the other ring member. The seals cooperate to prevent the entrance of dust and other foreign matter into the raceways and bearings.

Referring again to FIG. 1, a power transmission 27, powered by a hydraulic motor 28, is mounted on the upper unit to selectively rotate the upper unit on the undercarriage. The transmission terminates at a vertically disposed swing or output shaft 29 having a swing pinion 30 attached thereto (FIG. 4). The swing pinion is selectively driven against relatively stationary inner ring member or reaction ring gear 17 to effect such rotation.

Referring to FIGS. 2-5, an enclosure 31 of the present invention includes a horizontally disposed annular upper wall 32 which extends radially inwardly from swing bearing 13. The upper wall has a flat outer flange 33 sealingly secured between outer ring member 19 of the swing bearing and mounting ring 14 of upper unit 11. A horizontally disposed annular lower wall 34 is spaced vertically below the upper wall and has an outer flange 35 sealingly secured between inner ring member 17 of the bearing and support ring 16.

The lower wall extends radially inwardly from the swing bearing and has an outwardly extending inner sidewall 36 which is disposed generally vertically between the upper and lower walls and is concentric with respect to the swing bearing. A standard liquid gasket compound, not shown, may be pre-applied to both sides of flanges 33 and 35 prior to the assembly of the upper and lower walls to provide a leakproof seal thereat. An annular sealing means, such as lip seal 37, is secured to the upper edge of sidewall 36 to sealingly engage the upper wall. Seal 37, along with seal 26, fully seals an annular chamber 38 defined by wall means comprising walls 32, 34 and 36 and the toothed side of ring gear 17.

As shown in FIGS. 2 and 4, an aperture 39 is formed through upper wall 32 to permit swing pinion 30 to extend therethrough and into chamber 38. An annular seal 40 is positioned between the lower end of a tubular housing, rotatably mounting swing shaft 29 therein, and the upper wall to form a fluid tight joint therebetween.

A substantially annular U-shaped tray 41, disposed in chamber 38 and spaced apart from the wall means forming same, includes a pair of radially spaced sidewalls 42 and 43 extending vertically upwardly from a horizontally disposed, contiguous bottom wall 14, positioned vertically below ring gear 17. The upper ends of the sidewalls terminate at flanges 45 and 46, secured by welds or the like to upper wall 32. The tray is interrupted circumferentially to define an opening 47 (FIG. 2) aligned with aperture 39 formed in the upper wall, to accommodate pinion 30 therein.

A plurality of circumferentially spaced baffle plates 48 are secured within the tray to extend radially between sidewalls 42 and 43 to divide the tray into a plurality of individual compartments 49. The tray is concentrically arranged between the ring gear and sidewall 36. Sidewall 42 has a plurality of circumferentially spaced ports 50 formed therethrough (FIGS. 3 and 5), adjacent to ring gear 17, to communicate each compartment 49 with annular chamber 38.

A filler tube 51 (FIG. 3) is secured at its lower end to the upper wall and has a cap removably attached thereon for partially filling chamber 38 and compartments 49 with a lubricating oil. A dip stick assembly 52 is also secured to the upper wall and has a dip stick 53 removably attached thereto and positioned to have its lower end extend into one of the compartments 49. A standard drain plug 54 (FIG. 3) is removably attached to the lower wall to facilitate an oil change.

OPERATION

When vehicle 10 is substantially level, chamber 38 and compartments 49 are charged with lubricating oil through fillter tube 51. The lubricating oil will seek a common level due to the disposition of communicating ports 50. The chamber and compartments are preferably filled to at least cover the lower portions of ring gear 17. When swing pinion 30 is rotated to cause it to walk around the ring gear, lubricating oil will splash onto the meshing gear teeth to fully and continuously lubricate the teeth during usage.

Should the vehicle be tilted from a level position, such as when operating on a side slope, compartments 49 will function to maintain a fairly uniform distribution of the lubricating oil around chamber 38. The compartments maintained on the high side will trap and retain substantially all of the lubricating oil, originally contained therein when the machine was level, primarily due to the disposition of ports 50 on the outboard side of the compartments. Thus, only the limited amount of oil contained in the high side of chamber 38, between teeth 24 and sidewall 42, will run to the low side thereof.

Also, the compartments maintained on the low side will provide sufficient volume to receive such running oil. Such co-action between the high and low compartments will assure that a low oil level will be maintained at the low side of the chamber to inhibit oil leakage through lip seals 25 and 26 when the vehicle is operating on a side slope. However, a slight leakage of oil past lip seal 26 is acceptable for purposes of lubricating ball bearings 23.

In view of the foregoing, it is readily apparent that the present invention provides an improved enclosure and lubricating system for a gear drive mechanism. The enclosure prevents the entrance of dust and grit into the enclosure to greatly minimize wear normally occasioned in conventional mechanisms of this type. Furthermore, the enclosure contains a lubricant which may be maintained at a minimum level while yet continuously assuring adequate lubrication of all portions of the mechanism even during adverse operating conditions, such as side hill operations.