Arm for turbomachine casing comprising a body and a removable part

A turbomachine for an aircraft, comprising:

• a main shaft connecting a compressor rotor to a turbine rotor,
• a primary flow channel which passes through the compressor rotor and the turbine rotor,
• a casing comprising a casing hub arranged radially outwards from the primary flow channel, and a casing outer shell ring arranged radially outwards from the casing hub, the casing hub and the casing outer shell ring defining a secondary flow channel, and
• a transmission shaft formed of a primary transmission shaft and a secondary transmission shaft arranged end-to-end and extending along an orthogonal or tilted direction with respect to the main shaft,
• wherein:
• the casing outer shell ring comprises an orifice,
• the casing comprises an arm, the arm extending along a longitudinal direction and having:
• a first longitudinal end provided with first attachment means configured for being attached to the casing outer shell ring,
• a second longitudinal end provided with second attachment means configured for being attached to the casing hub, and
• two aerodynamic outer surfaces connected to one another at a leading edge of the arm,
• the arm further comprising:
• a shaft housing having a central axis which extends in the longitudinal direction of the arm, and
• a body forming a first part of each of the two aerodynamic outer surfaces, and comprising at least a part of the first attachment means, and at least a part of the second attachment means,
• wherein:
• the body comprises a recess arranged between a first part of the body situated on a leading edge side and a second part of the body situated on an opposite side, the recess leading to each of the two aerodynamic outer surfaces,
• the recess has a first opening and a second opening which open respectively at the first longitudinal end of the arm and at the second longitudinal end of the arm,
• the arm comprises a removable part housed in the recess so as to form a second part of each of the two aerodynamic outer surfaces,
• the removable part is configured to be inserted in the recess through the first opening by sliding movement of the removable part parallel to the longitudinal direction of the central axis, and
• the removable part delimits at least a part of the shaft housing extending from the first longitudinal end of the arm up to the second longitudinal end of the arm
• of which the first attachment means are attached to the casing outer shell ring and the second attachment means are attached to the casing hub, such that the orifice of the casing outer shell ring faces the shaft housing,
• the primary transmission shaft has a radially internal end coupled to the main shaft, and a radially external end,
• the secondary transmission shaft has a radially internal end coupled to the radially external end of the primary transmission shaft,
• the secondary transmission shaft is housed at least partially in the shaft housing of the arm, and
• the removable part is shaped to be able to be inserted through the orifice of the casing outer shell ring.

A method for disassembling a transmission shaft of a turbomachine, the turbomachine comprising:

• a main shaft connecting a compressor rotor to a turbine rotor,
• a primary flow channel which passes through the compressor rotor and the turbine rotor,
• a casing comprising a casing hub arranged radially outwards from the primary flow channel, and a casing outer shell ring arranged radially outwards from the casing hub, the casing hub and the casing outer shell ring defining a secondary flow channel, and
• the transmission shaft formed of a primary transmission shaft and a secondary transmission shaft arranged end-to-end and extending along an orthogonal or tilted direction with respect to the main shaft,
• wherein:
• the casing outer shell ring comprises an orifice,
• the casing comprises an arm, the arm extending along a longitudinal direction and having:
• a first longitudinal end provided with first attachment means configured for being attached to the casing outer shell ring,
• a second longitudinal end provided with second attachment means configured for being attached to the casing hub, and
• two aerodynamic outer surfaces connected to one another at a leading edge of the arm,
• the arm further comprising:
• a shaft housing having a central axis which extends in the longitudinal direction of the arm, and
• a body forming a first part of each of the two aerodynamic outer surfaces, and comprising at least a part of the first attachment means, and at least a part of the second attachment means,
• wherein:
• the body comprises a recess arranged between a first part of the body situated on a leading edge side and a second part of the body situated on an opposite side, the recess leading to each of the two aerodynamic outer surfaces,
• the recess has a first opening and a second opening which open respectively at the first longitudinal end of the arm and at the second longitudinal end of the arm,
• the arm comprises a removable part housed in the recess so as to form a second part of each of the two aerodynamic outer surfaces,
• the removable part is configured to be inserted in the recess through the first opening by sliding movement of the removable part parallel to the longitudinal direction of the central axis, and
• the removable part delimits at least a part of the shaft housing extending from the first longitudinal end of the arm up to the second longitudinal end of the arm
• of which the first attachment means are attached to the casing outer shell ring and the second attachment means are attached to the casing hub, such that the orifice of the casing outer shell ring faces the shaft housing,
• the primary transmission shaft has a radially internal end coupled to the main shaft, and a radially external end,
• the secondary transmission shaft has a radially internal end coupled to the radially external end of the primary transmission shaft,
• the secondary transmission shaft is housed at least partially in the shaft housing of the arm, and
• the removable part is shaped to be able to be inserted through the orifice of the casing outer shell ring,
• the method comprising steps of:
• removing the secondary transmission shaft through the orifice of the casing outer shell ring, then
• removing the removable part through the orifice of the casing outer shell ring, while the body of the arm remains attached to the casing outer shell ring and to the casing hub, then
• removing the primary transmission shaft through the recess of the body of the arm, then through the orifice of the casing outer shell ring.