Electric motor and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-2016336831-A1
Application number	US-201615152235-A
Country	US
Kind code	A1
Filing date	May 11, 2016
Priority date	May 13, 2015
Publication date	Nov 17, 2016
Grant date	—

Abstract

A terminal insertion hole is formed in a rear end frame. A grommet has a main body portion and a flanged portion. A terminal holding hole is formed in the main body portion of the grommet. The grommet is inserted into the terminal insertion hole of the rear end frame and the flanged portion is in contact with a rear-side axial-end surface of the rear end frame, that is, a peripheral portion of a rear-side open end of the terminal insertion hole. The grommet is assembled to the rear end frame by inserting the grommet into the terminal insertion hole from the rear-side open end.

First claim

What is claimed is:

1 . An electric motor comprising;
a rotor fixed to a rotating shaft; a first end frame for rotatably supporting a first shaft portion of the rotating shaft; a second end frame for rotatably supporting a second shaft portion of the rotating shaft; a stator core interposed between the first end frame and the second end frame in an axial direction of the electric motor and arranged at an outer periphery side of the rotor; a stator winding wound on the stator core; a terminal insertion hole formed in the second end frame and extending in the axial direction, the terminal insertion hole having a front-side open end formed at a front-side axial-end surface of the second end frame and opposing to the stator core and a rear-side open end formed at a rear-side axial-end surface of the second end frame opposite to the front-side axial-end surface; a coil terminal extending from the stator winding in a direction to the second end frame and inserted through the terminal insertion hole; and a grommet inserted into the terminal insertion hole so that the coil terminal is inserted through the grommet for holding the coil terminal by the second end frame, wherein the grommet has a main body portion, a terminal holding hole formed in the main body portion and a flanged portion formed at an outer periphery of the main body portion, wherein the coil terminal is inserted through the terminal holding hole, wherein the flanged portion is in contact with the rear-side axial-end surface surrounding the rear-side open end of the terminal insertion hole and thereby the grommet is attached to the second end frame.

2 . The electric motor according to claim 1 , further comprising;
a control circuit board provided on a side of the rear-side axial-end surface of the second end frame and controlling electric power supply to the stator winding, so that the control circuit board has a front-side surface opposing to the second end frame in the axial direction, wherein the control circuit board is located at a position opposing to the terminal insertion hole, wherein the coil terminal is connected to the control circuit board so as to electrically connect the control circuit board to the stator winding, wherein the flanged portion is formed at the outer periphery of the main body portion at its middle portion in the axial direction, a front-side part of the main body portion extending from the flanged portion to the terminal insertion hole is inserted into the terminal insertion hole, and a rear-side part of the main body portion extending from the flanged portion to the control circuit board is outwardly extending from the terminal insertion hole, wherein a first distance is made to be larger than a second distance, wherein the first distance corresponds to a length of the front-side part of the main body portion between the flanged portion and an inside contacting point at which the front-side part is in contact with an inner peripheral surface of the terminal insertion hole and which is located at a position most separated from the flanged portion among inside contacting points, and wherein the second distance corresponds to a distance in the axial direction between a forward end of the rear-side part of the main body portion and the front-side surface of the control circuit board.

3 . The electric motor according to claim 2 , further comprising;
a heat generating part mounted to the control circuit board, wherein the heat generating part generates heat when electric power is supplied to the heat generating part, wherein the second end frame has a heat sink portion between the rear-side axial-end surface and the control circuit board in the axial direction, and the heat sink portion radiates the heat generated at the heat generating part to an outside of the second end frame.

4 . The electric motor according to claim 2 , wherein
the grommet has a small-diameter portion in the rear-side part of the main body portion, a cross sectional area of the small-diameter portion is smaller than a cross sectional area of the coil terminal, in a condition that the grommet is not assembled to the second end frame, the grommet has a large-diameter portion in the front-side part of the main body portion, a cross sectional area of the large-diameter portion is larger than the cross sectional area of the small-diameter portion, in the condition that the grommet is not assembled to the second end frame, the forward end of the rear-side part of the main body portion is separated from the front-side surface of the control circuit board in the axial direction in the condition that the flanged portion is in contact with the rear-side axial-end surface surrounding the rear-side open end of the terminal insertion hole.

5 . The electric motor according to claim 1 , wherein
the grommet has a hook portion formed at a front-side end of the main body portion, so that the hook portion outwardly extends in the axial direction from the front-side open end of the terminal insertion hole and the hook portion is hooked to the front-side axial-end surface adjacent to the front-side open end.

6 . The electric motor according to claim 1 , further comprising;
a control circuit board provided on a side of the rear-side axial-end surface of the second end frame and controlling electric power supply to the stator winding; and a cover member connected to a part of an outer peripheral surface of the second end frame so as to cover the control circuit board, wherein the coil terminal electrically connects the control circuit board to the stator winding, wherein an outer peripheral surface of the stator core is not covered by the cover member so that the outer peripheral surface of the stator core is exposed to an outside of the electric motor, wherein the second end frame has a rear-end peripheral wall portion extending in the axial direction to the stator core and its front-side end is in contact with an outer periphery of the stator core, wherein a space is formed and surrounded by the rear-end peripheral wall portion between the stator core and the second end frame, and wherein the terminal insertion hole is formed in the second end frame at a position, which is inside of the rear-end peripheral wall portion in a radial direction of the electric motor toward the rotating shaft.

7 . The electric motor according to claim 1 , wherein
a front-side end of the main body portion of the grommet, which is located on a side to the stator core, is so arranged at a position that the front-side end of the main bod portion is not in contact with the stator winding, in the condition that the flanged portion is in contact with the rear-side axial-end surface of the rear end frame.

8 . A method for manufacturing the electric motor according to claim 1 comprising;
a step for inserting the coil terminal through the terminal insertion hole formed in the second end frame; and
a step for inserting the coil terminal through the terminal holding hole of the grommet and inserting the grommet into the terminal insertion hole from the rear-side open end, in a condition that the coil terminal is inserted through the terminal insertion hole, to thereby assemble the grommet to the second end frame.

9 . A method for manufacturing the electric motor according to claim 1 comprising;
a step for inserting the grommet into the terminal insertion hole of the second end frame from the rear-side open end, to thereby attach the grommet to the second end frame; and
a step for inserting the coil terminal through the terminal holding hole of the grommet, in a condition that the grommet is attached to the second end frame.

Assignees

• Denso Corp
• C/O Asmo Co Ltd

Inventors

• Horizumi Rintaro

Classifications

• H02K5/225

  Terminal boxes or connection arrangements (specially adapted for submersible motors H02K5/132) · CPC title

• H02K11/33

  Drive circuits, e.g. power electronics (H02K11/38 takes precedence) · CPC title

• H02K5/10 Primary

  with arrangements for protection from ingress, e.g. water or fingers · CPC title

• H02K11/30

  Structural association with control circuits or drive circuits · CPC title

• H02K9/22

  by solid heat conducting material embedded in, or arranged in contact with, the stator or rotor, e.g. heat bridges · CPC title