Apex seal arrangement for rotary internal combustion engine

Patent metadata

Field	Value
Publication number	US-2020325777-A1
Application number	US-201916382776-A
Country	US
Kind code	A1
Filing date	Apr 12, 2019
Priority date	Apr 12, 2019
Publication date	Oct 15, 2020
Grant date	—

Abstract

A rotor assembly for a rotary internal combustion engine is provided. The rotor assembly includes a rotor having a radial groove defined radially in a peripheral surface of the rotor. The groove has a depth and an intermediate shoulder at an intermediate depth. The groove has a first width therealong that is narrower than an intermediate width at the shoulder. An apex seal is received in the groove and protrudes from the peripheral face of the rotor. The apex seal is configured to move radially between a first position and a second position outward of the first position. A biasing member biases the apex seal toward the second position. A platform is disposed in the groove between the apex seal and the biasing member and has a width greater than the first width.

First claim

1 . A rotor assembly for a rotary internal combustion engine, the rotor assembly comprising:
a rotor having a radial groove defined radially in a peripheral surface of the rotor, the groove having a depth and an intermediate shoulder at an intermediate depth, the groove having a first width therealong that is narrower than an intermediate width at the shoulder; and an apex seal received in the groove and protruding from the peripheral face of the rotor, the apex seal configured to move radially between a first position and a second position outward of the first position, a biasing member biasing the apex seal toward the second position, and a platform disposed in the groove between the apex seal and the biasing member, the platform having a width greater than the first width.

2 . The rotor assembly as defined in claim 1 , wherein the platform has a first and a second surface defined on opposed sides thereof, the first surface interfacing with the biasing member and the second surface interfacing with an underside surface of the apex seal.

3 . The rotor assembly as defined in claim 2 , wherein the second surface of the platform and the underside surface of the apex seal have a corresponding relief.

4 . The rotor assembly as defined in claim 2 , wherein the second surface of the platform is flat underneath the underside surface of the apex seal.

5 . The rotor assembly as defined in claim 2 , wherein the first surface of the platform and the shoulder of the groove defines a flat interface.

6 . The rotor assembly as defined in claim 2 , wherein the shoulder of the groove is a first shoulder, the groove defining a second shoulder radially outward relative to the first shoulder, the second surface of the platform member engaging the second shoulder when the apex seal reaches the second radial position.

7 . The rotor assembly as defined in claim 2 , wherein the biasing member includes a leaf spring, the first surface of the platform defining a pair of longitudinally spaced apart notches to receive opposite longitudinal ends of the leaf spring.

8 . The rotor assembly as defined in claim 2 , wherein the biasing member includes a number of leaf springs disposed on one another, the first surface of the platform defining a corresponding number of pairs of longitudinally spaced apart notches to receive opposite longitudinal ends of respective leaf springs.

9 . The rotor assembly as defined in claim 1 , wherein the platform has opposite lateral edges extending along a length of the platform and spaced apart by a width of the platform, the width of the platform at at least one portion thereof is greater than a width of the apex seal.

10 . The rotor assembly as defined in claim 2 , wherein the platform has opposite lateral edges extending along a length of the platform, the lateral edges engaging respective opposite lateral walls of the groove, at least one of the lateral edges defining an indentation extending from the first surface to the second surface of the platform, the indentation defining a gas passage within the groove, the gas passage being between the lateral edge of the platform and the opposite lateral wall of the groove.

11 . The rotor assembly as defined in claim 1 , wherein the apex seal arrangement has a unitary apex seal extending along a majority of a distance between the end faces of the body.

12 . A rotary internal combustion engine comprising:
a stator body having a cavity defined by two axially spaced apart end walls and a peripheral wall extending between the end walls; a rotor having two axially spaced apart end faces each extending in proximity of a respective one of the end walls of the stator body, and a peripheral face extending between the end faces and defining an apex portion, the rotor body being engaged to an eccentric shaft to rotate within the cavity with the apex portion remaining adjacent the peripheral wall; at the apex portion the rotor having a groove extending radially inwardly into the rotor, the groove defining a shoulder at a radial distance from a radial end of the groove; an apex seal received in the groove and protruding radially from the peripheral face of the rotor, the apex seal configured to move along the groove between a first radial position set by the shoulder and a second radial position radially outward relative to the first radial position; a biasing member received in the groove, the biasing member biasing the apex seal radially outwardly toward the second radial position; and a platform received in the groove between the apex seal and the biasing member, the platform engaging the shoulder of the groove when the apex seal reaches the first radial position.

13 . The rotary internal combustion engine as defined in claim 12 , wherein the platform has a first and a second surface defined on opposed sides thereof, the first surface interfacing with the biasing member and the second surface interfacing with an underside surface of the apex seal.

14 . The rotary internal combustion engine as defined in claim 13 , wherein the shoulder of the groove is a first shoulder, the groove defining a second shoulder radially outward relative to the first shoulder, the second surface of the platform member engaging the second shoulder when the apex seal reaches the second radial position.

15 . The rotary internal combustion engine as defined in claim 13 , wherein the platform has opposite lateral edges extending along a length of the platform, the lateral edges engaging respective opposite lateral walls of the groove, at least one of the lateral edges defining an indentation extending from the first surface to the second surface of the platform, the indentation defining a gas passage between the lateral edge of the platform and the opposite lateral wall of the groove, the gas passage fluidly connecting opposed sides of the platform across the platform.

16 . A method of operating an apex seal engaged in a radial groove at an apex portion of a rotor of a rotary internal combustion engine, the method comprising:
allowing a radial travel of the apex seal along the groove over a distance defined between a first radial position and a second radial position, biasing the apex seal radially outward toward the second radial position via a biasing member, and interfacing a platform with a shoulder defined in the groove at a radial distance from an end of the groove when the apex seal reaches the first radial position, the platform located between the apex seal and the biasing member.

17 . The method as defined in claim 16 , wherein the shoulder is a first shoulder and the platform has a first and a second surface defined on opposed sides thereof, the first surface interfacing with the first shoulder when the apex seal reaches the first radial position and the second surface interfacing with a second shoulder defined in the groove radially outward relative to the first shoulder when the apex seal reaches the second radial position.

18 . The method as defined in claim 16 , further comprising balancing a gas pressure on opposed sides of the platform via a gas passage fluidly connecting the opposed sides of the platform, the platform having a lateral edge in proximity with an opposite lateral wall of the groove, the gas passage defined by an indentation in the lateral edge of the platform and the opposite lateral wall of the groove.

19 . The method as defined in claim 16 , further comprising allowing a pressurized gas from a working chamber of the rotary engine to flow radially inward along the groove and thro

Assignees

• Pratt & Whitney Canada

Inventors

• Vinski Johnny
• Gagnon-Martin David
• Gauvreau Jean-Gabriel
• Huppe Roger

Classifications

• Y02T10/12

  Improving ICE efficiencies · CPC title

• F01C21/08

  Rotary pistons (reciprocating pistons in general F16J) · CPC title

• F01C19/005

  Structure and composition of sealing elements such as sealing strips, sealing rings and the like; Coating of these elements (vane construction F01C21/0809; piston rings and ring sealings of similar construction in general F16J9/00) · CPC title

• F01C19/02

  Radially-movable sealings for working fluids · CPC title

• F01C1/22

  of internal-axis type with equidirectional movement of co-operating members at the points of engagement, or with one of the co-operating members being stationary, the inner member having more teeth or tooth- equivalents than the outer member · CPC title