# US 2013/0153082 A1 · Variable friction tires > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0153082 A1 - Document ID: US20130153082A1 - Status: Published application - Kind: A1 - Application number: 13/325,465 - Filed: 2011-12-14 - Published: 2013-06-20 - Earliest claimed: 2011-12-14 - Assignees: International Business Machines Corporation - Inventors: TIMOTHY M. LYNAR; KENT C. STEER - Web page: https://patentgrep.com/patent/US20130153082A1 ## CPC - B60C 5/22: the chambers being annular - B60C 5/02: having separate inflatable inserts, e.g. with inner tubes; Means for lubricating, venting, preventing relative movement between tyre and inner tube (B60C5/20 takes precedence) - B60C 23/00354: {Details of valves} - B60C 23/004: {the control being done on the wheel, e.g. using a wheel-mounted reservoir} - B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES ## Abstract A variable friction tire is provided. The variable friction tire includes a tire wall portion, a tread portion, a primary inflatable tube, and a secondary inflatable tube. The tread portion is for contacting the ground. The primary inflatable tube is at least partially encapsulated by the tire wall portion. The secondary inflatable tube is disposed between at least a portion of the tread portion and at least a portion of the primary inflatable tube. The secondary inflatable tube is selectively inflatable or deflatable in order to vary an amount of the tread portion in contact with the ground. ## Claims ### Claim 1 A variable friction tire, comprising: a tire wall portion; a tread portion for contacting the ground; a primary inflatable tube at least partially encapsulated by the tire wall portion; and a secondary inflatable tube disposed between at least a portion of the tread portion and at least a portion of the primary inflatable tube, wherein the secondary inflatable tube is selectively inflatable or deflatable in order to vary an amount of the tread portion in contact with the ground. ### Claim 2 (depends on 1) The variable friction tire of claim 1, wherein varying the amount of the tread portion in contact with the ground correspondingly varies an overall friction of the tire with respect to the ground. ### Claim 3 (depends on 1) The variable friction tire of claim 1, wherein a center portion of the tread portion is constructed to be harder and more durable than remaining portions of the tread portion. ### Claim 4 (depends on 1) The variable friction tire of claim 1, wherein an intended location of the secondary inflatable tube is maintained by any one of molding the primary inflatable tube and the secondary inflatable tube together, creating the primary inflatable tube and the secondary inflatable tube separately and gluing the primary inflatable tube and the secondary inflatable tube together, and forming the secondary inflatable tube within a channel in one or more of the tread portion and the primary inflatable tube. ### Claim 5 (depends on 1) The variable friction tire of claim 1, wherein the primary inflatable tube comprises an air supply passing aperture for allowing an air supply line to pass there through, and wherein the secondary inflatable tube comprises a connection for connecting to the air supply line. ### Claim 6 (depends on 1) The variable friction tire of claim 1, wherein the secondary inflatable tube comprises a valve for venting the secondary inflatable tube to atmospheric pressure. ### Claim 7 A method, comprising: providing a variable friction tire having a tire wall portion, a tread portion for contacting the ground, a primary inflatable tube at least partially encapsulated by the tire wall portion, and a secondary inflatable tube disposed between at least a portion of the tread portion and at least a portion of the primary inflatable tube; and selectively inflating or deflating the secondary inflatable tube in order to vary an amount of the tread portion in contact with the ground. ### Claim 8 (depends on 7) The method of claim 7, wherein varying the amount of the tread portion in contact with the ground correspondingly varies an overall friction of the tire with respect to the ground. ### Claim 9 (depends on 7) The method of claim 7, wherein the secondary inflatable tube is selectively inflated or deflated responsive to current vehicle status information. ### Claim 10 (depends on 9) The method of claim 9, wherein the current vehicle status information comprises one or more of velocity, steering, braking, and wheel slip. ### Claim 11 (depends on 7) The method of claim 7, wherein the secondary inflatable tube is selectively inflated or deflated while a corresponding vehicle on which the variable friction tire is mounted is in motion. ### Claim 12 (depends on 7) The method of claim 7, wherein the secondary inflatable tube is selectively inflated when a corresponding vehicle on which the variable friction tire is mounted is moving above a given threshold velocity so as to decrease the amount of the tread portion in contact with the ground. ### Claim 13 (depends on 7) The method of claim 7, wherein the secondary inflatable tube is selectively inflated when a corresponding vehicle on which the variable friction tire is mounted is moving above a given threshold velocity and within a threshold direction variation range so as to decrease the amount of the tread portion in contact with the ground. ### Claim 14 (depends on 7) The method of claim 7, wherein the secondary inflatable tube is selectively deflated when a corresponding vehicle on which the variable friction tire is mounted is moving in an unintended direction so as to increase the amount of the tread portion in contact with the ground. ### Claim 15 A variable friction tire system, comprising: at least one variable friction tire, having a tire wall portion, a tread portion for contacting the ground, a primary inflatable tube at least partially encapsulated by the tire wall portion, and a secondary inflatable tube disposed between at least a portion of the tread portion and at least a portion of the primary inflatable tube, the secondary inflatable tube being selectively inflatable or deflatable in order to vary an amount of the tread portion in contact with the ground; a secondary inflatable tube pressure control valve for connecting to an air source; an air supply line having a first end and a second end, the first end connected to the secondary inflatable tube and the second end connected to the secondary inflatable tube pressure control valve; and a control unit, connected to the secondary inflatable tube pressure control valve, for receiving current vehicle status information and controlling a pressure supplied to the secondary inflatable tube through the secondary inflatable tube pressure control valve based on the current vehicle status information. ### Claim 16 (depends on 15) The variable friction tire system of claim 15, wherein varying the amount of the tread portion in contact with the ground correspondingly varies an overall friction of the tire with respect to the ground. ### Claim 17 (depends on 15) The variable friction tire system of claim 15, wherein a center portion of the tread portion is constructed to be harder and more durable than remaining portions of the tread portion. ### Claim 18 (depends on 15) The variable friction tire system of claim 15, wherein an intended location of the secondary inflatable tube is maintained by one of the following: molding the primary inflatable tube and the secondary inflatable tube together, creating the primary inflatable tube and the secondary inflatable tube separately and gluing the primary inflatable tube and the secondary inflatable tube together, and forming the secondary inflatable tube within a channel in one or more of the tread portion and the primary inflatable tube. ### Claim 19 (depends on 15) The variable friction tire system of claim 15, wherein the primary inflatable tube comprises an air supply passing aperture for allowing the air supply line to pass there through, and wherein the secondary inflatable tube comprises a connection for connecting to the air supply line. ### Claim 20 (depends on 15) The variable friction tire system of claim 15, wherein the secondary inflatable tube comprises a valve for venting the secondary inflatable tube to atmospheric pressure. ### Claim 21 (depends on 15) The variable friction tire system of claim 15, wherein the current vehicle status information comprises one or more of velocity, steering, braking, and wheel slip. ### Claim 22 (depends on 15) The variable friction tire system of claim 15, wherein the secondary inflatable tube is selectively inflated or deflated while a corresponding vehicle on which the variable friction tire is mounted is in motion. ### Claim 23 (depends on 15) The variable friction tire system of claim 15, wherein the air source is an air tank. ### Claim 24 (depends on 23) The variable friction tire system of claim 23, wherein the control unit is configured to hold the secondary inflatable tube pressure control valve open and allow a pressure in the secondary inflatable tube to reach that of the air source when a vehicle velocity is above a certain threshold, a vehicle braking system is not being applied, and there is an absence of tire slip. ### Claim 25 (depends on 15) The variable friction tire system of claim 15, wherein the control unit varies the pressure supplied to the secondary inflatable tube based on vehicle velocity to enable a smooth transition between low friction and high friction driving modes.