A pump assembly is provided which comprises a pump housing, an electric motor attached to the pump housing and having a casing and an output shaft that protrudes into the pump housing to drive a pump within the pump housing, the output shaft having at least two supported portions by way of which the output shaft is rotatably supporting on the casing and the housing, respectively, and an elastic device interposed between one of the supported portions and one of the casing and the pump housing for damping radial vibrations of the output shaft.
1. A pump assembly comprising:
a pump housing;
an electric motor attached to the pump housing and having a casing and an output shaft that protrudes into the pump housing to drive a pump within the pump housing;
the output shaft having at least two supported portions by way of which the output shaft is rotatably supported on the casing and the pump housing, respectively; and
a damping device interposed between one of the supported portions and one of the casing and the pump housing for damping radial vibrations of the output shaft,
wherein the damping device includes a cylindrical spring that is deformable radially elastically.
2. A pump assembly according to claim 1 , wherein the pump housing comprises a shaft receiving hole in which the output shaft is partially disposed, the shaft receiving hole has a support hole section, the supported portions include a bearing installed in the support hole section and rotatably supporting an end portion of the output shaft, and the damping device is disposed between the bearing and the support hole section of the pump housing.
3. A pump assembly according to claim 1 , wherein the casing has an axial end formed with a support portion, the supported portions include a bearing installed in the support portion of the casing and rotatably supporting an end portion of the output shaft, and the damping device is disposed between the bearing and the support portion of the casing.
4. A pump assembly according to claim 1 , wherein the supported portions comprise a first bearing for rotatably supporting an end portion of the output shaft on the pump housing and a second bearing for rotatably supporting another end portion of the output shaft on the casing.
5. A pump assembly according to claim 4 , wherein the output shaft further comprises a supported portion that is constituted by a third bearing for rotatably supporting an intermediate portion of the output shaft on the casing.
6. A pump assembly according to claim 5 , wherein the cylindrical spring is interposed between the first bearing and the pump housing.
7. A pump assembly according to claim 5 , wherein the cylindrical spring is interposed between the second bearing and the casing.
8. A pump assembly according to claim 5 , wherein the output shaft comprises an eccentric cam at a position between the first bearing and the third bearing, and the pump comprises a plunger pump driven by the eccentric cam.
9. A pump assembly comprising:
a pump housing;
an electric motor attached to the pump housing and having a casing and an output shaft that protrudes into the pump housing to drive a pump within the pump housing;
the output shaft having at least two supported portions by way of which the output shaft is rotatably supported on the casing and the pump housing, respectively; and
a damping device interposed between one of the supported portions and one of the casing and the pump housing for damping radial vibrations of the output shaft,
wherein the damping device comprises a cylindrical spring in the form of a split ring and having a plurality of radially inward projections.
10. A pump assembly comprising:
a pump housing;
a pump disposed within the pump housing;
an electric motor attached to the pump housing and having a casing and an output shaft that protrudes into the pump housing to drive the pump;
a bearing unit for rotatably supporting at least two support portions of the output shaft on the pump housing and the casing, respectively; and
an elastic device interposed between the bearing unit and one of the pump housing and the casing for damping radial vibrations of the output shaft,
wherein the elastic device comprises a cylindrical spring in the form of a split ring and having a plurality of radially inward projections.
11. A pump assembly according to claim 10 , wherein the pump housing comprises a shaft receiving hole in which the output shaft is partially disposed, the shaft receiving hole has a support hole section, the support portions of the output shaft are constituted by a base end portion and a protruded end portion, respectively, the bearing unit includes a bearing installed in the support hole section and rotatably supporting the protruded end portion of the output shaft, and the elastic device is disposed between the bearing and the support hole section of the pump housing.
12. A pump assembly according to claim 10 , wherein the casing has a closed axial end formed with a support portion, the support portions of the output shaft are constituted by a base end portion and a protruded end portion, the bearing unit includes a bearing installed in the support portion of the casing and rotatably supporting the base end portion of the output shaft, and the elastic device is disposed between the bearing and the support portion of the casing.
13. A pump assembly according to claim 10 , wherein the support portions of the output shaft are constituted by a base end portion and a protruded end portion, the bearing unit comprises a rear bearing for rotatably supporting the base end portion of the output shaft on the casing and a terminal bearing for rotatably supporting the protruded end portion of the output shaft on the pump housing.
14. A pump assembly according to claim 13 , wherein the bearing unit further comprises a front bearing for rotatably supporting an intermediate portion of the output shaft on the casing.
15. A pump assembly according to claim 14 , wherein the cylindrical spring is interposed between the front bearing and the pump housing.
16. A pump assembly according to claim 14 , wherein the cylindrical spring is interposed between the rear bearing and the casing.
17. A pump assembly according to claim 14 , wherein the output shaft comprises an eccentric cam at a position between the front bearing and the terminal bearing, and the pump comprises a plunger pump driven by the eccentric cam.