# US 12,180,857 B2 · Turbine airfoil attachment with serration profile

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- Number: US 12,180,857 B2
- Document ID: US12180857B2
- Status: Granted
- Kind: B2
- Application number: 18/304,922
- Filed: 2023-04-21
- Published: 2024-10-24
- Granted: 2024-12-31
- Earliest claimed: 2023-04-21
- Assignees: Rtx Corporation
- Applicants: Raytheon Technologies Corporation
- Inventors: Emma J. Place; Bryan P. Dube; Pedro D. Laureano; Bernard Joseph Reilly, III; Mohamed Hassan; Edwin Otero; Andrew Correia; William R. Hackbarth, II; Jeffrey M. Jacques
- Web page: https://patentgrep.com/patent/US12180857B2

## CPC

- F01D 5/3007: {of axial insertion type}
- F01D 5/02: Blade-carrying members, e.g. rotors (rotors of non-bladed type F01D1/34; stators F01D9/00 {; selecting particular materials F01D5/28})
- F05D 2250/38: angled, e.g. sweep angle
- F05D 2250/72: symmetric
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

An attachment root for a blade includes a symmetric serration profile with multiple lobes. Contact surfaces of each lobe form equal contact angles with a line normal to a symmetry plane of the serration profile. Non-contact surfaces of lobes form angles greater than three degrees relative to the line that increase in a radially inward direction.

## Claims

### Claim 1

An attachment root of an airfoil comprising:
a serration profile that is symmetric about a plane bisecting the serration profile; and
a first lobe of the serration profile spaced from the plane and described relative to a line intersecting the serration profile that is normal to the plane, the first lobe comprising:
a first contact surface defining a first acute angle between the first contact surface and the line, wherein the first acute angle equals forty-five degrees; and
a first non-contact surface defining a second acute angle between the first non-contact surface and the line, wherein the second acute angle is greater than three degrees; and
a second lobe of the serration profile spaced from the symmetry plane, the second lobe comprising:
a second contact surface defining a third acute angle between the second contact surface and the line, wherein the third acute angle equals forty-five degrees; and
a second non-contact surface defining a fourth acute angle between the second non-contact surface and the line, wherein the fourth acute angle is greater than the second acute angle.

### Claim 2 (depends on 1)

The attachment root of claim 1, further comprising:
a third lobe of the serration profile spaced from the plane, the third lobe comprising:
a third contact surface defining a fifth acute angle between the third contact surface and the line, wherein the fifth acute angle equals forty-five degrees; and
a second non-contact surface defining a sixth acute angle between the third non-contact surface and the line, wherein the sixth acute angle is greater than forty-five degrees.

### Claim 3 (depends on 2)

The attachment root of claim 2, wherein the second acute angle is at least seven degrees and the fourth acute angle is at least twelve degrees.

### Claim 4 (depends on 3)

The attachment root of claim 3, wherein the second acute angle is less than twelve degrees and the fourth acute angle is less than seventeen degrees.

### Claim 5 (depends on 1)

The attachment root of claim 1, further comprising:
a first end face; and
a second end face parallel to the first end face, wherein the serration profile extends from the first end face to the second end face, and wherein the plane defines a plane angle with the first end face greater than or equal to eighty degrees and less than ninety degrees.

### Claim 6 (depends on 5)

The attachment root of claim 5, further comprising:
a first bevel at the intersection of the serration profile and the first end face; and
a second bevel at the intersection of the serration profile and the second end face that is parallel to the first bevel, wherein the first bevel defines a bevel angle with the first end face greater than or equal to seventy degrees and less than or equal to seventy-five degrees.

### Claim 7

A rotor blade comprising:
a platform;
an airfoil extending from the platform in a spanwise direction to a tip and in a chordwise direction from a leading edge to a trailing edge; and
an attachment root extending from the platform opposite the airfoil, the attachment root comprising:
a serration profile that is symmetric about a plane bisecting the serration profile; and
a first lobe of the serration profile spaced from the plane and described relative to a line intersecting the serration profile that is normal to the plane, the first lobe comprising:
a first contact surface defining a first acute angle between the first contact surface and the line, wherein the first acute angle equals forty-five degrees; and
a first non-contact surface defining a second acute angle between the first non-contact surface and the line, wherein the second acute angle is greater than three degrees; and
a second lobe of the serration profile spaced from the plane, the second lobe comprising:
a second contact surface defining a third acute angle between the second contact surface and the line, wherein the third acute angle equals forty-five degrees; and
a second non-contact surface defining a fourth acute angle between the second non-contact surface and the line, wherein the fourth acute angle is greater than the second acute angle.

### Claim 8 (depends on 7)

The rotor blade of claim 7, further comprising:
a third lobe of the serration profile spaced from the plane, the third lobe comprising:
a third contact surface defining a fifth acute angle between the third contact surface and the line, wherein the fifth acute angle equals forty-five degrees; and
a third non-contact surface defining a sixth acute angle between the third non-contact surface and the line, wherein the sixth acute angle is greater than forty-five degrees.

### Claim 9 (depends on 8)

The rotor blade of claim 8, wherein the second acute angle is at least seven degrees and the fourth acute angle is at least twelve degrees.

### Claim 10 (depends on 9)

The rotor blade of claim 9, wherein the second acute angle is less than twelve degrees and the fourth acute angle is less than seventeen degrees.

### Claim 11 (depends on 7)

The rotor blade of claim 7, further comprising:
a first end face; and
a second end face parallel to the first end face, wherein the serration profile extends from the first end face to the second end face, and wherein the plane defines a plane angle with the first end face greater than or equal to eighty degrees and less than ninety degrees.

### Claim 12 (depends on 11)

The rotor blade of claim 11, further comprising:
a first bevel at the intersection of the serration profile and the first end face; and
a second bevel at the intersection of the serration profile and the second end face parallel to the first bevel, wherein the first bevel defines a bevel angle with the first end face greater than or equal to seventy degrees and less than or equal to seventy-five degrees.

### Claim 13

A high-pressure turbine comprising:
a rotor;
an airfoil;
an attachment root coupling the airfoil to the rotor, the attachment root comprising:
a serration profile that is symmetric about a plane bisecting the serration profile; and
a first lobe of the serration profile spaced from the plane and described relative to a line intersecting the serration profile that is normal to the plane, the first lobe comprising:
a first contact surface defining a first acute angle between the first contact surface and the line, wherein the first acute angle equals forty-five degrees; and
a first non-contact surface defining a second acute angle between the first non-contact surface and the line, wherein the second acute angle is greater than three degrees; and
a second lobe of the serration profile spaced from the plane, the second lobe comprising:
a second contact surface defining a third acute angle between the second contact surface and the line, wherein the third acute angle equals forty-five degrees; and
a second non-contact surface defining a fourth acute angle between the second non-contact surface and the line, wherein the fourth acute angle is greater than the second acute angle.

### Claim 14 (depends on 13)

The high-pressure turbine of claim 13, further comprising:
a third lobe of the serration profile spaced from the plane, the third lobe comprising:
a third contact surface defining a fifth acute angle between the third contact surface and the line, wherein the fifth acute angle equals forty-five degrees; and
a third non-contact surface defining a sixth acute angle between the third non-contact surface and the line, wherein the sixth acute angle is greater than forty-five degrees.

### Claim 15 (depends on 14)

The high-pressure turbine of claim 14, wherein the second acute angle is at least seven degrees and the fourth acute angle is at least twelve degrees, and wherein the second acute angle is less than twelve degrees and the fourth acute angle is less than seventeen degrees.

### Claim 16 (depends on 13)

The high-pressure turbine of claim 13, further comprising:
a first end face; and
a second end face parallel to the first end face, wherein the serration profile extends from the first end face to the second end face, and wherein the plane defines a plane angle with the first end face greater than or equal to eighty degrees and less than ninety degrees.

### Claim 17 (depends on 16)

The high-pressure turbine of claim 16, further comprising:
a first bevel at the intersection of the serration profile and the first end face; and
a second bevel at the intersection of the serration profile and the second end face parallel to the first bevel, wherein the first bevel defines a bevel angle with the first end face greater than or equal to seventy degrees and less than or equal to seventy-five degrees.