DIFFERENTIAL PINION BEARING LUBE PUMP

• US 3,618,712 A
• Filed: 02/24/1970
• Issued: 11/09/1971
• Est. Priority Date: 02/24/1970
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Robert Casey
• Inventors: Casey, Robert
• Primary Examiner(s): Antonakas, Manual A.
• Application Number:
  US05/013,595
• Time in Patent Office: 623 Days
• Field of Search: 184/6,6TT,6Y,11R,11A,27R 308/27A
• US Class Current: 184/6.28
• CPC Class Codes: F16C 19/548 in O-arrangement
• CPC Class Codes: F16C 2361/61 Toothed gear systems, e.g. support of pinion shafts in general F16H57/02
• CPC Class Codes: F16H 2048/423 characterised by bearing arrangement
• CPC Class Codes: F16H 57/0434 relating to lubrication supply, e.g. pumps arrangement of pumps F16H57/0441; Pressure control grooves with pumping effect for supplying lubricant F16H57/0428; generation and variation of line pressure for transmission control F16H61/0021
• CPC Class Codes: F16H 57/0483 Axle or inter-axle differentials
• CPC Class Codes: F16N 13/10 with mechanical drive F16N13/18 takes precedence

Abstract

Lubricating and cooling oil is supplied to the pinion bearings of a differential by means of a pump located within the differential housing. The pump is of the plunger operated variety and is driven from the differential case to pump the oil contained within the differential housing to the bearings.

Claims

1. A lubrication system for a differential that includes a housing, a ring gear and differential case rotatably mounted in the housing and being at least partially immersed in oil pooled in the bottom portion of said housing, a pinion gear meshing with the ring gear, said pinion gear having a shaft secured thereto rotatably supported by bearings spaced coaxially of the shaft and carried by the housing;

said lubrication system comprising a positive-displacement pump disposed within the bottom portion of said housing and having an inlet port in direct communication with the oil contained within said housing, and an outlet port, eccentric means mounted directly on the ring gear mechanism and differential case for driving said pump from said ring gear mechanism in response to rotation thereof to pump said oil into said inlet port and out of said outlet port, and means defining a flow path between said outlet port and said bearings to deliver oil pumped out of said outlet port to said bearings and thereby positively lubricate same.

2. A lubrication system according to claim 1, further defined by said pump being a plunger operated pump including an operating plunger projecting from a pump casing, said eccentric means for driving the pump comprising a cam carried by said differential case of said ring gear and engaging said plunger.

3. A lubrication system according to claim 2, further defined by said plunger operated pump comprising a piston coaxially secured to said plunger and mounted for reciprocation coaxially of a cylinder bore formed in said casing, resilient means disposed within said bore and acting between a base of said casing and said piston to normally resiliently maintain said piston and plunger in an extended position, said cam thereby alternately depressing said plunger and piston and permitting extension thereof under the loading of said resilient means, said piston and base of said casing axially defining a pump chamber within said bore, means including said inlet port defining a valved inlet passage to said pump chamber, and means including said outlet port defining a valved outlet passage from said pump chamber, said valved inlet and outlet passages being operable to permit flow to said pump chamber through said inlet passage during an extension stroke of said piston and flow from said pump chamber through said outlet passage during a depression stroke of said piston.

4. A lubrication system according to claim 3, further defined by said means defining a valved inlet passage comprising a guide bushing extending through said base of said casing and projecting coaxially into said cylinder bore, said bushing slidably coaxially receiving a depending guide head of said plunger, said bushing inwardly flared at its exterior end to define a valve seat circumscribing an opening defining said inlet port, said bushing having an opening communicating the interior of said bushing with said pump chamber, and a check valve supported upon said valve seat, and said means defining a valved outlet passage comprising means defining an outlet cavity within said casing and a communicating duct extending from said pump chamber to said cavity, the juncture between said duct and said cavity formed with a second valve seat, means defining an opening extending exteriorly of said cavity to define said outlet port, and a second check valve supported upon said second valve seat.

5. A lubRication system according to claim 10, further defined by said means defining a flow path comprising an annular bearing cage, an annular carrier secured to said housing and concentrically mounting said cage, said carrier and cage defining an annular cavity therebetween, means mounting said bearings coaxially within the bore of said cage with the portion of said shaft between said bearings spaced radially inward from the wall of said cage bore to thereby define therewith an annular cavity coaxially between said bearings, said inboard bearing disposed to face the interior of said housing, said cage having at least one duct communicating said cavity between said cage and casing with said cavity coaxially between said bearings, and conduit means connecting said pump outlet port to said cavity between said cage and carrier.

6. A lubrication system according to claim 5, further defined by said duct terminating in said cavity coaxially between said bearings at a location adjacent the furthest outboard bearing.

7. A lubrication system according to claim 5, further defined by said pump being a plunger operated pump including an operating plunger projecting from a pump casing, said means for driving the pump comprising a cam carried by said differential case and engaging said plunger.

8. A lubrication system according to claim 7, further defined by said plunger operated pump comprising a piston coaxially secured to said plunger and mounted for reciprocation coaxially of a cylinder bore formed in said casing, resilient means disposed within said bore and acting between a base of said casing and said piston to normally resiliently maintain said piston and plunger in an extended position, said cam thereby alternately depressing said plunger and piston and permitting extension thereof under the loading of said resilient means, said piston and base of said casing axially defining a pump chamber within said bore, means including said inlet port defining a valved inlet passage to said pump chamber, and means including said outlet port defining a valved outlet passage from said pump chamber, said valved inlet and outlet passages being operable to permit flow to said pump chamber through said inlet passage during an extension stroke of said piston and flow from said pump chamber through said outlet passage during a depression stroke of said piston.

9. A lubrication system according to claim 8, further defined by said means defining a valved inlet passage comprising a guide bushing extending through said base of said casing and projecting coaxially into said cylinder bore, said bushing slidably coaxially receiving a depending guide head of said plunger, said bushing inwardly flared at its exterior end to define a valve seat circumscribing an opening defining said inlet port, said bushing having an opening communicating the interior of said bushing with said pump chamber, and a check valve supported upon said valve seat, and said means defining a valved outlet passage comprising means defining an outlet cavity within said casing and a communicating duct extending from said pump chamber to said cavity, the juncture between said duct and said cavity formed with a second valve seat, means defining an opening extending exteriorly of said cavity to define said outlet port, and a second check valve supported upon said second valve seat.

10. The lubrication system of claim 1, wherein said eccentric means operates said pump regardless of the direction in which said ring gear mechanism and differential case rotate.