JP2020102983A - Motor cooling structure - Google Patents

Abstract

To provide a cooling structure that easily cools a coil and the like for a motor in which a tip end side of a coil end of a stator is covered with a resin member.SOLUTION: A motor cooling structure 10 includes a rotor arranged with a substantially horizontal rotation axis, and a stator core 22 arranged coaxially around the rotor. A coil 24 is attached to a stator core 22. The vicinity of the tip of the coil end 24b of the coil 24 is covered with an insulating resin 26. A supply port 44a for supplying cooling oil is provided above the outer peripheral surface of the insulating resin 26, and a guideway 30 that guides the cooling oil flowing from the upper part to the coil end 24b is provided below the supply port 44a on the outer peripheral surface of the insulating resin 26.SELECTED DRAWING: Figure 1

Description

The present invention relates to a motor cooling structure having a stator in which the vicinity of the tip of a coil end is covered with an insulating resin.

The stator and the like in the motor may be cooled using a liquid refrigerant such as oil. For example, in order to cool a coil in a stator that is heated to a high temperature by Joule heat of an electric current, a liquid refrigerant is supplied to a protruding portion (called a coil end) from an axial end of a stator core in the coil for cooling.

The following Patent Document 1 describes a configuration in which a coolant passage having a closed cross-sectional shape is provided at each of the outer circumference, the inner circumference, and the coil end axial end of the stator.

In Patent Document 2 below, a refrigerant formed inside a coil end by covering the coil end with a three-sided annular member that covers the outer circumference, the inner circumference, and the axial end of the coil end is formed. The flow path is described. Protrusions are provided on the inside of the member to block the flow of the liquid refrigerant flowing in the coil end in the circumferential direction and create a flow in the axial direction along the coil.

Patent Document 3 below describes a configuration in which an annular guide plate that comes into contact with the coil end is provided at the axial end of the coil end. The liquid refrigerant supplied to the coil ends is caused to flow in the circumferential direction along the guide plates at the coil end ends.

JP, 2017-139872, A International Publication No. 2015/181889 International Publication No. 2010/041673

In the configuration of Patent Document 1 described above, by providing the coolant flow path for cooling the coil end, the motor becomes large and heavy. In addition, the techniques of Patent Documents 1 to 3 are considered to be inefficient when the tip end side of the coil end is covered with an insulating resin because the insulating resin has low thermal conductivity.

An object of the present invention is to realize a cooling structure for easily cooling a coil or the like for a motor in which a tip end side of a coil end of a stator is covered with a resin member.

A cooling structure for a motor according to the present invention includes a rotor arranged with its rotation axis substantially horizontal, a stator core coaxially arranged on the outer periphery of the rotor, a coil attached to the stator core, and an axial direction of the coil. An insulating resin that covers the vicinity of the tip of the coil end, which is an end, a supply port that supplies the liquid refrigerant to the upper part of the outer peripheral surface of the insulating resin, and a supply port that is provided below the supply port on the outer peripheral surface of the insulating resin. And a guide path for guiding the liquid refrigerant flowing from the upper part to the coil end.

According to the present invention, the flow of the liquid refrigerant is controlled with a simple configuration, and it becomes possible to enhance the cooling efficiency of the coil including the coil end, and further the stator and the motor.

FIG. 3 is a simplified front view of the motor cooling structure according to the embodiment. FIG. 3 is a simplified side view of the motor cooling structure according to the embodiment. It is a perspective view of a protrusion. It is a figure explaining the flow of cooling oil.

Embodiments will be described below with reference to the drawings. In the description, specific modes are shown to facilitate understanding, but these are examples of the embodiment, and various other embodiments are possible.

FIG. 1 is a schematic front view (a view seen from a rotation axis direction) of a motor (electric motor) cooling structure 10 according to the embodiment, and FIG. 2 is a side view. The motor is provided with a rotor whose rotation axis is substantially horizontal (for example, the angle formed by the rotation axis and the horizontal line is within ±10 degrees), but the rotor is not shown in the figure. Then, only the stator 20 arranged around the rotor and the supply passage 40 of the liquid refrigerant are shown. In the coordinate system in the figure, the z axis indicates the rotation axis direction, the r axis indicates the radial direction orthogonal to the rotation axis, and the θ axis indicates the rotation direction. Further, the g-axis indicates the vertically downward direction (the same applies to FIGS. 3 and 4).

The stator 20 is formed with a cylindrical stator core 22 as a skeleton. The stator core 22 is formed, for example, by stacking a large number of electromagnetic steel plates punched into a predetermined shape in the axial direction. The inner circumference of the stator core 22 is provided with a plurality of slots (grooves). The coil 24 is attached by winding a conductive wire in this groove. In the embodiment, a large number of U-shaped segment coils, which are U-shaped conducting wires, are inserted into the slots from one end side in the axial direction, and the other end side is welded and connected to form a coil. I'm assuming. Therefore, the coil has a portion called a coil end that protrudes outward in the axial direction from the axial end surface of the stator core 22 on both axial ends of the stator core 22. In FIG. 2, the coil end 24a is formed on the side into which the U-shaped segment coil is inserted, and the coil end 24b is formed by welding.

In the welded coil end 24b, the insulating coating on the surface of the segment coil is peeled off, so that the insulating property is temporarily not ensured. Therefore, after welding, an insulation process is performed in which the tip end side of the coil end 24b is dipped in a resin material (referred to as an insulating resin) having an insulating property such as varnish and hardened. The insulating resin 26 in FIGS. 1 and 2 is a substantially cylindrical member formed in this way, and covers the tip end side of the coil end 24b like a lid to ensure insulation from the outside and to protect the inside. The insulation between each segment coil is also secured.

A protrusion 28 is provided on the outer peripheral surface of the insulating resin 26. In FIG. 1, the protrusion 28 is provided at a position of about 1:30 when the insulating resin 26 is likened to a timepiece (a position rotated about 45 degrees clockwise from the top in the circumferential direction).

Here, the shape of the protrusion 28 will be described with reference to FIG. FIG. 3 is a perspective view of the protrusion 28. The protrusion 28 is formed in a shape in which a part of a triangular prism having a surface perpendicular to the rotation axis (a surface stretched by the r axis and the θ axis) as a triangle is cut off by the inclined surface 28a. By providing the inclined surface 28a, the guide path 30 is formed between the protrusion 28 and the insulating resin 26 so as to be inclined vertically downward toward the coil end 24b. As will be described later, the guide passage 30 can guide the cooling oil flowing from the upper portion of the insulating resin 26 to the coil end 24b side. In addition, in the embodiment, it is assumed that the protrusion 28 is integrally formed at the same time as the insulating resin 26, but may be attached later.

The description will be continued with reference to FIGS. 1 and 2 again. A cooling oil supply passage 40 is installed above the stator 20. The cooling oil is an example of a liquid refrigerant, and for example, ATF (Automatic transmission fluid) is used. Although not shown, the motor according to the embodiment is assumed to be entirely surrounded by a housing (motor case). The cooling oil is made to flow into the supply passage 40 by pumping up what has accumulated at the bottom of the housing with a pump.

The supply path 40 includes a main supply path 42 along the rotation axis direction, a sub supply path 44 for supplying the upper part of the outer peripheral surface of the insulating resin 26 and a sub supply path 46 for supplying the upper part of the outer peripheral surface of the coil end 24b. , 48 are included. Of these, as shown in FIG. 1, the sub supply path 44 is provided only on the right side of FIG. 1 with respect to the top of the insulating resin 26, and is not provided on the left side of FIG. This is because the auxiliary supply passage 44 is provided for the purpose of allowing the cooling oil supplied from the supply port 44a at the tip end to flow toward the protrusion 28 (the guide passage 30). Since the insulating resin 26 generally has poor thermal conductivity, the cooling effect of the cooling oil flowing on the surface of the insulating resin 26 has almost no cooling effect on the coil end 24b. On the other hand, for the coil end 24b, as shown in FIG. 1, a sub supply passage 46 is provided on the right side of FIG. 1 with respect to the top portion, and a sub supply passage 48 is provided on the left side of FIG. Cooling oil flows from the supply ports 46a and 48a at these tips to the outer surface of the coil end 24b. When the cooling oil directly contacts the coil end 24b, a great cooling effect can be expected.

Subsequently, the flow of the cooling oil will be described with reference to FIG. FIG. 4 is a view showing the motor cooling structure 10 from the same direction as in FIG. 1, but the outline of the insulating resin 26 in FIG. 1 is shown by a dotted line, and the cross section of the coil end 24b is schematically illustrated. Showing. As described above, the coil end 24b is formed by sequentially welding a large number of U-shaped segment coils according to the circuit design. Although the circuit design and the formation of the coil end 24b can be performed in various ways, in the present embodiment, each conductor wire of the coil end 24b is oblique along the diagonal line drawn in the region of the coil end 24b in FIG. It is supposed to be placed. Various arrangements of the conductors on the coil end 24b are known, and in addition to the arrangement shown in FIG. 4, for example, the conductors are arranged along the circumferential direction, and have appropriate expansion in the circumferential direction. It is possible to adopt various things such as an arrangement mode in which the direction is different for each block.

The cooling oil tends to flow vertically downward due to gravity, and tends to flow along the conductor wire due to surface tension. Here, first, the trace lines 50a, 50b, 50c of the cooling oil discharged from the supply port 48a of the auxiliary supply passage 48 will be viewed. The trace line 50a flows long along the conductor on the outer peripheral surface of the coil end 24b. The trajectory 50b shows the flow that enters the inside of the coil end 24b at an early stage, but then moves along the conducting wire. The trace line 50c shows the flow along the conducting wire after entering the inside of the coil end 24b immediately after being discharged from the supply port 48a.

In this way, the trace lines 50a, 50b, 50c are directed toward the outer peripheral side of the coil end 24b along the conducting wire in the process of falling vertically downward due to gravity. As a result, the cooling oil discharged from the supply port 48a of the auxiliary supply passage 48 flows to the upper part of the coil end 24b on the left side in FIG. 4 (range from 9 o'clock to 12 o'clock when viewed as a clock) to cool the same. Is going.

Next, trace lines 52a, 52b, 52c of the cooling oil discharged from the supply port 46a of the auxiliary supply passage 46 will be viewed. At the trace line 52a, the cooling oil initially flows on the outer peripheral surface of the coil end 24b, but after once entering the inside of the coil end 24b, the cooling oil moves toward the inner peripheral side of the coil end 24b along the conducting wire. There is. The same applies to the trajectory 52b. The trace line 52c enters the inside of the coil end 24b immediately after being discharged from the supply port 46a, and then heads toward the inner peripheral side of the coil end 24b along the conducting wire.

In this way, the trace lines 52a, 52b, 52c are directed toward the inner peripheral side of the coil end 24b along the conducting wire while falling vertically downward due to gravity. As a result, the cooling oil discharged from the supply port 46a of the sub supply path 46 flows to the upper part of the coil end 24b and slightly to the right thereof (range from 12:00 to 1:00 when compared to a clock) to be cooled. I'm just doing. That is, it can be seen that the cooling oil does not flow much in the vicinity of the right side of the upper part of the coil end 24b (around 2 o'clock to 3 o'clock when it is regarded as a clock), and the cooling does not proceed.

Therefore, in the embodiment, the cooling oil supplied from the supply port 44a of the auxiliary supply passage 44 is used to cool the vicinity of the upper right side of the coil end 24b. The trace lines 54a and 54b show the flow of the cooling oil from the supply port 44a. The cooling oil first flows down on the outer surface of the insulating resin 26 and reaches the protrusion 28. As shown in FIG. 2, the guide path 30 (the lowermost portion) formed by the inclined surface 28a of the protrusion 28 and the insulating resin 26 is vertically lower toward the coil end 24b. Therefore, most of the cooling oil flows in the guide passage 30 toward the coil end 24b side, and further flows down along the wall surface of the insulating resin 26 on the coil end 24b side. Then, after reaching the outer peripheral surface of the coil end 24b, a part thereof flows downward along the outer peripheral surface for a while like the trajectory 54a, then flows into the inside of the coil end 24b, and the inner peripheral side of the coil end 24b. Head to. In addition, a part thereof quickly enters the inside of the coil end 24b like the trajectory line 54b and goes toward the inner peripheral side of the coil end 24b.

In this way, the cooling oil discharged from the supply port 44a of the auxiliary supply passage 44 flows to the right side of the upper part of the coil end 24b (range from 2 o'clock to 3 o'clock when it is likened to a clock) for cooling. .. As a result, the cooling oil supplied by the three auxiliary supply paths 44, 46, and 48 flows over the entire upper part of the coil end 24b (a range from 9 o'clock to 3 o'clock when it is likened to a clock), and cools this range. It will be. Further, the lower part of the coil end 24b is cooled by the cooling oil which is widely dispersed and flows down from the upper part.

In the above description, the protrusion 28 is provided on the outer surface of the insulating resin 26 at around 1:30 to form the guide path 30. However, the position where the protrusion 28 is provided should be appropriately adjusted depending on the direction of the conductor wire at the coil end 24b. For example, the protrusions 28 may be provided on the left side of the top of the insulating resin 26, or may be provided on the left and right sides. Moreover, if the flow is controlled so that a part of the cooling oil that reaches the protrusions 28 will go over the protrusions 28 (or form a gap in the protrusions 28) and flow toward the lower part, there will be two or more protrusions 28 on one side. The provided mode can also be implemented.

Further, in the above description, the guide path 30 is formed of the insulating resin 26 and the protrusion 28 having the inclined surface 28a. However, for example, the guide path 30 may be formed by forming a recess in the insulating resin 26. Although the insulating resin 26 is provided only on one coil end 24b, the above-described embodiment can be similarly applied to the case where it is provided on both coil ends 24a and 24b. ..

10 Motor Cooling Structure, 20 Stator, 22 Stator Core, 24 Coil, 24a, 24b Coil End, 26 Insulating Resin, 28 Projection, 28a Inclined Surface, 30 Induction Path, 40 Supply Path, 42 Main Supply Path, 44, 46, 48 Sub-supply path, 44a, 46a, 48a Supply port, 50a, 50b, 50c, 52a, 52b, 52c, 54a, 54b Trace line.

Claims (1)

A rotor arranged with its axis of rotation substantially horizontal,
A stator core coaxially arranged on the outer periphery of the rotor,
A coil attached to the stator core;
An insulating resin that covers the vicinity of the tip of the coil end, which is the axial end of the coil,
A supply port for supplying a liquid refrigerant to the upper part of the outer peripheral surface of the insulating resin,
A guide path that is provided below the supply port on the outer peripheral surface of the insulating resin, and that guides the liquid refrigerant flowing from above to the coil end,
A cooling structure for a motor, comprising: