Electric motor and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-10411547-B2
Application number	US-201615152235-A
Country	US
Kind code	B2
Filing date	May 11, 2016
Priority date	May 13, 2015
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

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, the second end frame comprising a rotor-facing axial-end surface and a rotor-opposing axial-end surface, wherein the rotor-facing axial-end surface faces toward the rotor and the rotor-opposing axial-end surface faces away from and opposes the rotor;
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 and being composed of multiple stator coils, each of which has multiple coil terminals;
a pair of terminal insertion holes, each of which is formed in the second end frame and extending in the axial direction, and each of which has a rotor-facing open end formed at a rotor-facing axial-end surface of the second end frame and a rotor-opposing open end formed at a rotor-opposing axial-end surface of the second end frame;
each of the coil terminals of each stator coil extending from the stator winding in a direction to the second end frame and inserted through the terminal insertion holes; and
a pair of grommets, each of which is inserted into each of the terminal insertion holes so that the coil terminals of each stator coil is inserted through the grommets for holding the multiple coil terminals by the second end frame,
wherein each of the grommets has a main body portion having a cross section of a non-circular shape, multiple terminal holding holes formed in the main body portion, a flanged portion formed at an outer periphery of the main body portion, and a hook portion,
wherein each of the coil terminals is inserted through each of the terminal holding holes,
wherein the flanged portion is in contact with the rotor-opposing axial-end surface of the second end frame surrounding the rotor-opposing open end of the terminal insertion holes and thereby the grommets are attached to the second end frame, and
wherein the hook portion is formed at a rotor-facing end of the main body portion and extends in a radial-inward direction, so that the hook portion is hooked to the rotor-facing axial-end surface of the second end frame adjacent to the rotor-facing open end of the terminal insertion holes.

2. The electric motor according to claim 1 , further comprising:
a control circuit board provided on a side of the rotor-opposing 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 rotor-facing surface that opposes the second end frame in the axial direction,
wherein the control circuit board is located at a position that opposes the terminal insertion holes in the axial direction,
wherein the coil terminals are 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 rotor-facing part of the main body portion extending from the flanged portion to each respective terminal insertion hole is inserted into the respective terminal insertion hole, and a rotor-opposing part of the main body portion extending from the flanged portion to the control circuit board is outwardly extending from each 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 rotor-facing part of the main body portion between the flanged portion and an inside contacting point at which the rotor-facing part is in contact with an inner peripheral surface of the terminal insertion holes 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 rotor-opposing part of the main body portion and the rotor-facing 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 rotor-opposing 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
each of the terminal holding holes of the grommets has a small-diameter portion in the rotor-opposing 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 terminals, in a condition that the grommets are not assembled to the second end frame,
each of the terminal holding holes of the grommets has a large-diameter portion in the rotor-facing 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 grommets are not assembled to the second end frame,
the forward end of the rotor-opposing part of the main body portion is separated from the rotor-facing surface of the control circuit board in the axial direction in the condition that the flanged portion is in contact with the rotor-opposing axial-end surface surrounding the rotor-opposing open end of the terminal insertion holes.

5. The electric motor according to claim 1 , further comprising:
a control circuit board provided on a side of the rotor-opposing 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 terminals electrically connect 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 rotor-facing 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 holes are 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.

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

7. A method for manufacturing the electric motor according to claim 1 comprising:
a step for inserting the coil terminals through the terminal insertion holes formed in the second end frame; and
a step for inserting the coil terminals through the terminal holding holes of the grommets and inserting the grommets into the terminal insertion holes from the rotor-opposing open end, in a

Assignees

• Denso Corp
• C/O Asmo Co Ltd

Inventors

• Horizumi Rintaro

Classifications

• H02K11/30

  Structural association with control circuits or drive circuits · CPC title

• H02K5/10 Primary

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

• 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

• H02K15/33

  Connecting winding sections; Forming leads; Connecting leads to terminals · CPC title