Electric motor-integrated rocket engine pump

1 . An electric motor-integrated rocket engine pump comprising:

a housing;

a rotating body provided in a first direction inside the housing;

an electric motor provided inside the housing and integrally shaft-coupled to the rotating body; and

a plurality of fluid bearings mounted on the rotating body to support rotation of the rotating body,

wherein the rotating body includes:

a center shaft extending in the first direction;

a permanent magnet provided in a circumferential direction on an outer circumferential surface of the center shaft;

a journal for encasing the center shaft in a longitudinal direction; and

an impeller connected to a front end of the journal in the longitudinal direction, and provided on a portion of the outer circumferential surface of the center shaft protruding from the front end of the journal in the longitudinal direction,

wherein the rotating body further includes:

a first side cap and a second side cap for capping longitudinally both ends of the permanent magnet respectively;

an inducer connected to a front end of the impeller and provided on a portion of the outer circumferential surface of the center shaft that is protruding from the front end of the impeller; and

a nut fastened to the portion of the outer circumferential surface of a front end of the center shaft in the longitudinal direction at a front of the inducer, and

wherein the center shaft, the permanent magnet, the journal, the impeller, the first side cap, the second side cap, and the inducer, which are temporarily coupled to each other, are integrally assembled by the nut.

2 . The electric motor-integrated rocket engine pump of claim 1 , wherein the housing includes a first housing, a second housing, and a third housing sequentially coupled in a longitudinal direction of the rotating body.

3 . The electric motor-integrated rocket engine pump of claim 2 , wherein the first housing encases the impeller and one fluid bearing provided on an outer circumferential surface of the journal in the longitudinal direction among the plurality of fluid bearings,

wherein the first housing has a first flow path for supplying lubricating fluid to the one fluid bearing, and

wherein the one fluid bearing includes a fluid journal bearing.

4 . The electric motor-integrated rocket engine pump of claim 3 , further comprising a first seal member,

wherein the first seal member is disposed on a front side and a rear side of the impeller that is inside the first housing, and

wherein the first seal member is disposed on a front side and a rear side of the one fluid bearing.

5 . The electric motor-integrated rocket engine pump of claim 2 , wherein the second housing is coupled to a rear end of the first housing so as to encase the electric motor and one fluid bearing provided to face a front side of a thrust disc provided outward in a radial direction from a rear end of the journal in the longitudinal direction among the plurality of fluid bearings,

wherein the second housing has a cooling flow path for cooling the electric motor and a second flow path for supplying lubricating fluid to the one fluid bearing, and

wherein the one fluid bearing includes a fluid thrust bearing.

6 . The electric motor-integrated rocket engine pump of claim 5 , further comprising a second seal member,

wherein the second seal member is disposed on the front side of the one fluid bearing.

7 . The electric motor-integrated rocket engine pump of claim 2 , wherein the third housing is coupled to a rear end of the second housing so as to encase, among the plurality of fluid bearings,

one fluid bearing provided to face a rear side of a thrust disc provided outward in the radial direction from a rear end of the journal in the longitudinal direction; and

another fluid bearing provided on the outer circumferential surface of the rear end of the journal in the longitudinal direction at a rear of the one fluid bearing,

wherein the third housing has a third flow path for supplying lubricating fluid to the one fluid bearing and the another fluid bearing, and

wherein the another fluid bearing includes a fluid journal bearing.

8 . The electric motor-integrated rocket engine pump of claim 7 , further comprising a third seal member,

wherein the third seal member is disposed on a rear side of the one fluid bearing and is disposed on a front side and a rear side of the another fluid bearing.

9 . The electric motor-integrated rocket engine pump of claim 1 , wherein the plurality of fluid bearings includes two fluid journal bearings and two fluid thrust bearings,

wherein a first fluid journal bearing of the two fluid journal bearings is provided on an outer circumferential surface of a front end in a longitudinal direction of the rotating body,

wherein a second fluid journal bearing of the two fluid journal bearings is provided on the outer circumferential surface of a rear end in the longitudinal direction of the rotating body, and

wherein the two fluid thrust bearings are provided to face both side surfaces of a thrust disc provided outward in a radial direction from a longitudinal rear end of the rotating body.

10 . The electric motor-integrated rocket engine pump of claim 1 , wherein a blocking disc for blocking a movement of the second side cap in the longitudinal direction protrudes outward in a radial direction on one side of the outer circumferential surface in the longitudinal direction of the center shaft.

11 . The electric motor-integrated rocket engine pump of claim 1 , wherein the center shaft has a step in the circumferential direction on one side in the longitudinal direction, the step blocks a movement of the first side cap coupled to the outer circumferential surface of the center shaft in the longitudinal direction, and a gap is generated between the first side cap and the step due to an accumulation tolerance when the center shaft, the permanent magnet, the journal, the impeller, the first side cap, the second side cap, and the inducer are finally assembled by the nut.

12 . The electric motor-integrated rocket engine pump of claim 1 , wherein the center shaft has a diameter smaller than a diameter of the journal, and

wherein a rear end of the center shaft in the longitudinal direction has an outer diameter coming into close contact with an inner diameter of the journal.

13 . The electric motor-integrated rocket engine pump of claim 1 , wherein the center shaft has an outer diameter smaller than an inner diameter of the journal, and an empty space is provided between the journal and a portion other than one side portion of the center shaft to which the permanent magnet, the first side cap and the second side cap are fastened.