# US 10,370,047 B2 · Seal structure of crawler-driving apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,370,047 B2 - Document ID: US10370047B2 - Status: Granted - Kind: B2 - Application number: 15/422,430 - Filed: 2017-02-01 - Published: 2017-06-15 - Granted: 2019-08-06 - Earliest claimed: 2012-03-30 - Assignees: KYB Corporation - Applicants: KYB Corporation - Inventors: Yoshikazu Hirota; Chikashi Imoto; Kazumi Ito; Junichiro Sugimoto; Eishin Noguchi; Kaori Kawabata - Web page: https://patentgrep.com/patent/US10370047B2 ## CPC - B62D 55/088: with means to exclude or remove foreign matter, e.g. sealing means, self-cleaning track links or sprockets, deflector plates or scrapers - F16J 15/002: {comprising at least two sealings in succession (F16J15/162, F16J15/40 take precedence)} - F16J 15/008: {with provision to put out of action at least one sealing; One sealing sealing only on standstill; Emergency or servicing sealings (F16J15/164 takes precedence)} - F16J 15/3204: with at least one lip - F16J 15/344: {the pressing force being applied by means of an elastic ring supporting the slip-ring} - F16J 15/3464: {Mounting of the seal} - B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M) - F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS ## Abstract A seal structure is provided to block a clearance between a rotational casing and a fixed housing for driving a crawler of a crawler vehicle. A seal ring is held in a first annular holding groove provided in the fixed housing together with a first O-ring that biases the seal ring toward the outside of the first holding groove. A second holding groove having an opening facing the first holding groove is provided in the rotational casing to hold a slide ring having a higher rigidity than that of the seal ring together with a second O-ring that biases the slide ring toward the seal ring. A foreign object such as mud is thereby prevented from invading a gear chamber without increasing a frictional loss. ## Claims ### Claim 1 A seal structure of a crawler-driving apparatus, arranged between a rotational casing that drives a crawler of a crawler vehicle and a fixed housing fixed to a vehicle body of the crawler vehicle, comprising: a first holding groove in an annular shape, the first holding groove being formed in one of the rotational casing and the fixed housing; a second holding groove in an annular shape, the second holding groove being formed in another one of the rotational casing and the fixed housing to face the first holding groove; a seal ring held in the first holding groove; a slide ring that is held in the second holding groove and has a higher rigidity than that of the seal ring; a first elastic member held in the first holding groove to bias the seal ring towards the slide ring; and a second elastic member held in the second holding groove to bias the slide ring towards the seal ring, wherein, one of the seal ring and the slide ring has an annular guide protrusion protruding to another one of the seal ring and the slide ring, an annular guide trench that makes sliding contact with the guide protrusion is formed in the other one of the seal ring and the slide ring, the first holding groove has a first outer circumferential groove side surface and a first inner circumferential groove side surface extending in a direction of the rotation axis of the rotational casing, the second holding groove has a second outer circumferential groove side surface and a second inner circumferential groove side surface extending in the direction of the rotation axis of the rotational casing, the slide ring contacts both the first outer circumferential groove side surface and the first inner circumferential groove side surface of the first holding groove, and the slide ring contacts both the second outer circumferential groove side surface and the second inner circumferential groove side surface of the second holding groove. ### Claim 2 (depends on 1) The seal structure according to claim 1, wherein the guide trench is formed in the slide ring, the guide protrusion is formed in the seal ring, and the slide ring is engaged with the first and second holding grooves. ### Claim 3 (depends on 1) The seal structure according to claim 1, wherein the guide trench has a pair of conical surfaces, and the guide protrusion has a pair of conical sliding contact portions that make sliding contact with the pair of conical surfaces. ### Claim 4 (depends on 1) The seal structure according to claim 1, wherein both the first and second elastic members are rings having an X-shaped cross section. ### Claim 5 (depends on 1) The seal structure according to claim 1, wherein the seal ring has the guide protrusion protruding toward the slide ring, and the slide ring has the guide trench that receives and has a shape matching a shape of the guide protrusion of the seal ring. ### Claim 6 (depends on 5) The seal structure according to claim 5, wherein the guide protrusion of the seal ring has an isosceles-triangular cross section, and the guide trench of the slide ring has an isosceles-triangular cross section. ### Claim 7 (depends on 1) The seal structure according to claim 1, wherein the guide protrusion has a first conical surface and a second conical surface, and the guide trench has a first sliding contact portion having a first conical shape matching the first conical surface, and a second sliding contact portion having a second conical shape matching the second conical surface. ### Claim 8 (depends on 7) The seal structure according to claim 7, wherein the first conical surface of the guide protrusion is contactable with the first sliding contact portion of the guide trench, and the second conical surface of the guide protrusion is contactable with the second sliding contact portion of the guide trench. ### Claim 9 (depends on 1) The seal structure according to claim 1, wherein the seal ring contacts both the first outer circumferential groove side surface and the first inner circumferential groove side surface of the first holding groove. ### Claim 10 (depends on 1) The seal structure according to claim 1, wherein the seal ring includes a resin ring, and the slide ring includes a metal ring. ### Claim 11 (depends on 1) The seal structure according to claim 1, wherein the seal ring includes a resin ring, and the slide ring includes a resin ring with a lower frictional coefficient than a frictional coefficient of the seal ring. ### Claim 12 (depends on 1) The seal structure according to claim 1, wherein one of the rotational casing and the fixed housing has an annular convex portion that protrudes into another one of the rotational casing and the fixed housing, has an end face, and is formed concentrically with a rotation axis of the rotational casing, the other one of the rotational casing and the fixed housing has an annular concave portion having a bottom surface to receive the annular convex portion, the first holding groove has an opening in the bottom surface of the annular concave portion, the second holding groove has an opening in the end face of the annular convex portion, a gap between the bottom surface of the annular concave portion and the end face of the annular convex portion located outward from the first and second holding grooves is communicated with an outside of the rotational casing and the fixed housing through a radial gap formed between the rotational casing and the fixed housing in an outer circumference of the annular convex portion, and an axial gap formed between the rotational casing and the fixed housing at an end of the radial gap, a gap between the end face of the annular convex portion and the bottom surface of the annular concave portion located inward from the first and second holding grooves is communicated with a gear chamber through a radial gap formed between the rotational casing and fixed housing in an inner circumference of the annular convex portion, and the gear chamber is filled with lubricant and formed in the rotational casing. ### Claim 13 (depends on 1) The seal structure according to claim 1, wherein a radial opening width of the second holding groove is equal to a radial opening width of the first holding groove.