WO2011128732A2

WO2011128732A2 - Method of arranging temperature-sensing element, and motor

Info

Publication number: WO2011128732A2
Application number: PCT/IB2011/000519
Authority: WO
Inventors: Tomonori Furukawa; Kazutaka Aoki
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 2010-04-12
Filing date: 2011-03-11
Publication date: 2011-10-20
Also published as: JP2011223768A; WO2011128732A3

Abstract

A coil (22) is composed of windings (70) each including a conductor (62) having electric conductivity, a first insulator layer (66) that covers the conductor (62), and a second insulator layer (68) that covers the first insulator layer (66). The second insulator layer (68) is removed from each of the windings (70) to expose the first insulator layer (66). A temperature-sensing element (80) detects the temperature of the coil (22), and is arranged on the exposed first insulator layer (66). The invention allows changes in temperature caused by the energization of the coil to be detected accurately, even in a motor that utilizes windings covered with a plurality of insulating materials in the stator core.

Description

METHOD OF ARRANGING TEMPERATURE-SENSING ELEMENT, AND MOTOR

I

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The invention relates to a method of arranging a temperature-sensing element, and a motor equipped with the temperature-sensing element.

2. Description of the Related Art

[0002] An example of a generally employed motor will be described. A motor 10 shown in FIG. 4 includes a stator 12, which serves as a stationary part that forms a hollow region in an inner region thereof, and a rotor 14, which serves as a rotating part that faces the inner region of the stator 12 and rotates with a shaft 16.

[0003] The stator 12 includes a stator core 13 and a coil 22 that is wound around the stator core 13. Further, coil ends 22a and 22b protrude from both ends of the stator core 13 respectively. The coil 22 is formed of a plurality of windings constituting a multiple-phase coil, for example, a three-phase coil composed of a U-phase coil, a V-phase coil, and a W-phase coil or the like.

[0004] In a system that includes the motor 10, an increase in the temperature of the motor 10 resulting from the energization of the coil 22 is detected by a temperature sensing element such as a thermistor or the like, and is utilized for failsafe control (see, e.g., Japanese Patent Application Publication No. 2008-131775 (JP-A-2008-131775)).

[0005] As shown in FIGS. 5 A and 5B, a winding 170 (see FIG. 5 A) according to the related art is formed by covering a conductive wire 162 having good electric conductivity, which is made of copper or the like, with an insulator layer 164 formed from a thin film made of, for example, enamel resin. If the winding 170 is utilized as the coil 22 shown in FIG. 4, a temperature-sensing element 80, such as a thermistor, is usually directly arranged and fixed on a surface of the single winding 170 or over the surfaces of a plurality of windings 170 (see FIG. 5B). The temperature of the surfaces of the windings 170 detected by the temperature-sensing element 80is transmitted to a control portion (not shown), and utilized for system control. In general, enamel resin conducts sufficient heat. Accordingly, the discrepancy between the external temperature of the coil 22 detected by the temperature-sensing element 80 arranged according to this simple method and the internal temperature of the coil 22 introduces only a negligible error in the measurement.

[0006] FIG. 1 A shows, a conventional winding 70 having a cross-sectional shape as shown in where the conductor 62 has a generally rectangular cross-section, and the insulator layer 64 covers the outer periphery of the conductor 62 to insulate the conductor 62. The insulator layer 64 is formed of a first insulator layer 66 and a second insulator layer 68, which are arranged in the stated order over the conductor 62. The first insulator layer 66 is formed of, for example, enamel resin, and has the same composition as the insulator layer 164 constituting the winding 170 shown in FIG. 5 A. However, the second insulator layer 68 is made of an insulating material that is more rigid and has a lower heat conductivity than the first insulator layer 66, for example, polyphenylene sulfide (PPS) resin or the like.

[0007] Accordingly, in the winding 70 shown in FIG. 1A, the insulator layer 64 covering the conductor 62 generally has a lower heat conductivity than the insulator layer 164 covering the conductor 162 in the conventional winding 170 shown in FIG. 5 A. Thus, by arranging the temperature- sensing element on the surface of the winding in accordance with the conventional method shown in FIG. 5B, it may not be possible to accurately measure the internal temperature of the winding 70.

SUMMARY OF THE INVENTION

[0008] The invention provides a method of appropriately arranging a

temperature-sensing element to accurately detect temperature changes resulting from the energization of a stator coil even in a motor utilizing the stator coil constructed of windings that is improved in insulating properties by being covered with a plurality of insulating materials. The invention also provides a motor provided with the

temperature-sensing element. [0009] The invention is constructed as will be described below.

[0010] A first aspect of the invention relates to a method of arranging a temperature-sensing element for a motor equipped with a stator forming a hollow region in an inner periphery side thereof and a rotor that is arranged in the hollow region and can rotate facing the stator, the stator including a stator core, and a coil wound around the stator core. The coil is composed of windings each including a conductor having electric conductivity, a first insulator layer covering the conductor, and a second insulator layer covering the first insulator layer. In this method, the second insulator layer is removed from each of the windings to expose at least part of the first insulator layer, and the temperature-sensing element, which serves to detect a temperature of the coil, is arranged on the exposed first insulator layer.

[0011] Further, the temperature-sensing element may be arranged in the vicinity of a joint portion obtained by joining conductors of two windings exposed by removing the first insulator layer and the second insulator layer therefrom.

[0012] Further, the first insulator layer may be made of enamel resin, and the second insulator layer may be made of polyphenylene sulfide resin.

[0013] A second aspect of the invention relates to a motor equipped with a stator that includes a stator core and a coil wound around the stator core and forms a hollow region on an inner periphery side thereof, a rotor that is arranged in the hollow region and can rotate facing the stator, and a temperature-sensing element for detecting a

temperature of the coil. In this motor, the coil is composed of windings each including a conductor having electric conductivity, a first insulator layer covering the conductor, and a second insulator layer covering the first insulator layer, and the temperature-sensing element is arranged on a surface of the first insulator layer, which is partially exposed by removing the second insulator layer from each of the windings.

[0014] Further, the temperature-sensing element may be arranged in the vicinity of a joint portion obtained by joining conductors of two windings exposed by removing the first insulator layer and the second insulator layer therefrom.

[0015] Further, the temperature- sensing element may be so arranged as to be sandwiched between the two windings.

[0016] Even in a motor utilizing windings improved in insulating properties by being covered with a plurality of insulating materials, the invention allows changes in temperature resulting from the energization of a coil to be detected accurately.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The foregoing and further features and advantages of the invention will become apparent from the following description of example embodiments of the invention with reference to the accompanying drawings, wherein like numerals are used to represent like elements, and wherein:

FIGS. 1 A and IB show the arrangement of a temperature-sensing element on a coil employing a winding 70;

FIG. 2 shows the arrangement of the temperature- sensing element in the vicinity of a joint portion between windings;

FIG. 3 is a partial cross-sectional view of a stator to show a practical use of an embodiment of the invention as exemplified in FIG. 2;

FIG. 4 shows the overall construction of a motor 10; and

FIGS. 5 A and 5B show the arrangement of a temperature-sensing element on a coil employing windings 170 according to the related art.

DETAILED DESCRIPTION OF EMBODIMENTS

[0018] Embodiments of the invention will be described hereinafter using the drawings. [0019] FIG. IB shows an example arrangement of a temperature-sensing element according to one embodiment of the invention. First, part of a second insulator layer 68 is removed from a winding 70 having a cross-sectional shape as shown in FIG. 1 A by using an appropriate method, such as peeling, to expose the first insulator layer 66. A temperature-sensing element 80 is then placed on the surface of the exposed first insulator layer 66. According to this construction, even in a motor utilizing the winding 70 covered with an insulator layer 64 made.of a plurality of insulating materials, changes in the temperature inside a coil 22 can be accurately measured by the temperature-sensing element 80.

[0020] In the embodiment of the invention, the winding 70 shown in FIGS. 1A and IB may have a non-rectangular cross-sectional shape, such as, for example, a circular or elliptical cross-sectional shape. Further, the insulator layer 64 that covers the outer periphery of the conductor 62 is not limited in particular as long as it has a multi-layer structure, for example, a triple-layer structure or the like. In other words, the insulator layer 64 is not restricted to a double-layer structure as shown in FIGS. 1A and IB.

[0021] In the embodiment of the invention, the method of fixing the

temperature-sensing element 80 laid over the first insulator layer 66 is not limited in particular. For example, the temperature-sensing element 80 may be fixed using an adhesive material such as varnish or the like, or a part or whole including the

temperature-sensing element 80 may be molded from thermoplastic resin. Further, although FIG. IB shows the removal of the second insulator layer 68 from the winding 70 over the entire outer periphery of the first insulator layer 66, this is not an absolute requirement. For example, part of the first insulator layer 66, such as the region of the first insulator layer 66 on an upper side or an upper region of the winding 70, may be exposed so that the temperature-sensing element 80 may be laid and fixed thereon.

[0022] FIG. 2 shows an example of the arrangement of a temperature-sensing element according to another embodiment of the invention. As shown in FIG. 2, near a joint portion 92 for electrically connecting the conductor 62 exposed at an end of the winding 70 and a conductor 82 exposed at an end extended from another winding 90 to each other through a known treatment such as welding, caulking or the like, the second insulator layer 68 and a second insulator layer 88 are generally removed, and exposed regions of the first insulator layer 66 and a first insulator layer 86 exist. Because the temperature-sensing element 80 is installed on the regions of the first insulator layers 66 and 86 that are already exposed, no additional step for installing the temperature-sensing element 80 is required. Therefore, the arrangement of the temperature-sensing element 80 according to this embodiment of -the invention is preferable. It should be noted that although the temperature-sensing element 80 is arranged on the winding 70 side in FIG. 2, it may also be arranged on the winding 90 side, and that the temperature-sensing element 80 may also be so arranged as to be sandwiched between the winding 70 and the winding 90 as still another embodiment of the invention.

[0023] FIG. 3 is shows an example of practical use of the embodiment of the invention as exemplified in FIG. 2. FIG. 3 is a partial cross-sectional view of the stator core 13 and the coil 22 wound around the stator core 13 in the motor 10 depicted in FIG. 4. I

[0024] In FIG. 3, the temperature-sensing element 80 is arranged at a joint region 100 between a lead wire 75 (equivalent to the winding 70 shown in FIG. 2) drawn out from the terminal region of a spiral winding 22 and a connecting wire 95 (equivalent to the winding 90 shown in FIG. 2) that extends from another spiral winding (not shown), at a region where the first insulator layer is exposed by removal of the second insulator layer. In the embodiment of the invention, the joint region 100 may be covered with insulative fine resin particles and heated, if necessary, to be subjected to a melting treatment. This configuration makes it possible not only to reliably insulate an exposed conductor (see FIG. 2) region but also to appropriately detect the internal temperature of the coil to which heat is transferred via the lead wire 75 and the connecting wire 95.

[0025] In the embodiments of the invention, any type of temperature-sensing element, such as a known thermistor with high measuring accuracy or the like, may be used as the temperature-sensing element 80. For example, a thermocouple or the like that has been made compact enough to be installed on the winding 70 is applicable.

[0026] The invention may be utilized in any type of motor that executes controls based on the temperature of a coil detected by a temperature-sensing element.

[0027] Although the invention has been described with reference to the example embodiments thereof, it is to be understood that the invention is not limited to the particulars of the disclosed embodiments. To the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the example embodiments of the invention are shown in various combinations and configurations, other combinations and configurations, including more, less or only a single element, are also within the scope of the invention. I

Claims

CLAIMS: I

1. A method of arranging a temperature-sensing element in a motor equipped with a stator that includes a stator core and a coil wound around the stator core and forms a hollow region on an inner periphery side thereof, and with a rotor that is arranged in the hollow region and rotates facing the stator, wherein the coil is composed of windings each including a conductor having electric conductivity, a first insulator layer that covers the conductor, and a second insulator layer that covers the first insulator layer, the method comprising:

removing the second insulator layer from each of the windings to expose at least a portion of the first insulator layer; and

arranging the temperature sensing element, which detects a temperature of the coil, on the exposed first insulator layer.

2. The method according to claim 1, wherein the temperature-sensing element is arranged in a vicinity of a joint portion obtained by joining conductors of two windings exposed by removing the first insulator layer and the second insulator layer therefrom.

3. The method according to claim 1 or 2, wherein the first insulator layer is made of enamel resin, and ;

the second insulator layer is made of polyphenylene sulfide resin.

4. A motor comprising:

a stator that includes a stator core and a coil wound around the stator core and forms a hollow region on an inner periphery side thereof;

a rotor that is arranged in the hollow region and rotates facing the stator; and a temperature-sensing element that detects a temperature of the coil,

wherein the coil is composed of windings, each of which includes a conductor having electric conductivity, a first insulator layer covering the conductor, and a second ;.^■·- insulator layer covering the first insulator layer, and

the temperature-sensing element is arranged on a surface of the first insulator layer, which is partially exposed by removing the second insulator layer from each of the windings.

5. The motor according to claim 4, wherein the temperature-sensing element is arranged in a vicinity of a joint portion obtained by joining conductors of two windings exposed by removing the first insulator layer and the second insulator layer therefrom.

6. The motor according to claim 5, wherein the temperature-sensing element is sandwiched between the two windings.