Electric motor axial stator winding temperature sensor

Abstract

An apparatus, a temperature sensor and a method for assembling an electric motor axial stator winding temperature sensor are disclosed. In a particular embodiment, the temperature sensor includes a housing configured to be fixed relative to the motor. The temperature sensor also includes a plunger disposed in the housing and a thermal sensor disposed in the plunger. In this embodiment, the plunger is movable relative to the housing to position the thermal sensor relative to the electric motor.

Description

Technical Field

[0001] The present disclosure relates to a temperature sensor for use with an electric motor. Background Art

[0002] Different systems like automobiles are increasingly using motors (electric motors). However, electric motors may overheat during use, resulting in motor and / or system failures. Some conventional electric motor designs incorporate negative temperature coefficient (NTC) thermistors to monitor the temperature of the stator windings of the motor. NTCs may be preferred due to their relatively low component cost. However, NTCs are not repairable and may have relatively low accuracy. In addition, it may be desirable for NTCs to monitor the temperature of welded hairpins associated with the stator. However, the tolerances associated with welded hairpins tend to be quite large, making it difficult to ensure accurate temperature measurements. Therefore, there is a need in the art for improved sensing systems to prevent electric motor overheating and failures. Summary of the invention

[0003] An apparatus, a temperature sensor, and a method for assembling an electric motor axial stator winding temperature sensor are disclosed. In a specific embodiment, the temperature sensor includes a housing configured to be fixed relative to the electric motor. The temperature sensor also includes a plunger disposed in the housing and a thermal sensor disposed in the plunger. In this embodiment, the plunger can be moved relative to the housing to position the thermal sensor relative to the electric motor.

[0004] In another embodiment, a method of assembling a temperature sensor is disclosed, the temperature sensor having a housing, a plunger, and a thermal sensor. The method includes axially inserting the plunger into an opening defined by a neck portion of the housing. In this embodiment, the housing is configured to be coupled to an electric motor, and the plunger is movable relative to the housing to position the thermal sensor relative to the electric motor. The method also includes coupling one or more electrical connectors within the temperature sensor so that the thermal sensor is electrically coupled to a connector configured for connection to an external system.

[0005] The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular description of exemplary embodiments of the invention as illustrated in the accompanying drawings wherein like reference numerals generally represent like parts of exemplary embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] So that those skilled in the art to which the disclosed systems and techniques pertain will more readily understand how to make and use them, reference may be made to the following drawings.

[0007] Figure 1A is a diagram illustrating a perspective view of a temperature sensor used with an electric motor according to an embodiment of the present disclosure.

[0008] Figure 1B It's a picture. Figure 1A Schematic diagram of different views of a temperature sensor.

[0009] Figure 1C It's a picture. Figure 1A FIG. 1 is an illustration of a cross-sectional view of a temperature sensor.

[0010] Figure 1D It's a picture. Figure 1A FIG. 1 is an exploded cross-sectional view of a temperature sensor.

[0011] Figure 2 is a flow chart illustrating an implementation of a method for assembling a temperature sensor according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0012] For the purpose of describing a particular example, the terms used herein are not intended to limit other examples. Whenever a singular form such as "a", "an" and "the" is used and only a single element is neither explicitly nor implicitly defined as mandatory, other examples may also use plural elements to implement the same function. Similarly, when a function is subsequently described as being implemented using multiple elements, further examples may use a single element or processing entity to implement the same function. It will be further understood that the terms "comprises", "comprising", "includes" and / or "including" specify the presence of the features, wholes, steps, operations, processes, actions, elements and / or parts when used, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, processes, actions, elements, parts and / or any groups thereof.

[0013] It will be understood that when an element is referred to as being "connected" or "coupled" to another element, the elements may be directly connected or coupled or via one or more intermediate elements. If two elements A and B are combined using "or", this should be understood to disclose all possible combinations, i.e., only A, only B, and A and B. An alternative wording for the same combination is "at least one of A and B". The same applies to combinations of more than two elements.

[0014] Therefore, although further examples are capable of various modifications and alternative forms, some specific examples thereof are shown in the accompanying drawings and will be described in detail later. However, this detailed description does not limit other examples to the specific forms described. Other examples may encompass all modifications, equivalents, and alternatives that fall within the scope of the present invention. Throughout the description of the accompanying drawings, the same reference numerals represent the same or similar elements, which, when compared to each other, may be implemented identically or in a modified form while providing the same or similar functions.

[0015] The subject technology overcomes prior art problems associated with conventional temperature sensors used with electric motors. For example, the systems and techniques described herein provide a temperature sensor that facilitates measuring the temperature of a motor stator in an electric motor. In some examples, an electric motor may have a stator with one or more welded hairpins. The temperature of the hairpins may be a good indicator that the electric motor is operating properly (e.g., a higher temperature may indicate poor motor health).

[0016] To protect the stator windings of electric motors from overheating, current designs utilize glued / welded NTCs, which may be inexpensive in terms of components, but have several limitations that make it more expensive at the system level, i.e., non-repairable and with low accuracy. The sensor system described herein can provide improved and repeatable response time, high accuracy, a movable plunger in the axial direction, and a tight environmental seal. According to an embodiment of the present disclosure, the movable spring-preloaded plunger of the temperature sensor improves the appropriate response time measurement and compensation of the relative displacement of the stator windings of the motor housing. In addition, the thermal decoupling of the sensing element from the cooling medium also improves the accuracy measurement. In addition, rubber environmental seals and plastic welds / adhesives can provide sealing.

[0017] The systems and techniques disclosed herein may also facilitate the preparation and installation of temperature sensors on electric motors. The systems and techniques disclosed herein may also improve the operating range of vehicles using electric motors (e.g., by ensuring that the motors are functioning properly), improve safety outcomes associated with electric motors (e.g., by reliably sensing motor anomalies), and / or reduce assembly time.

[0018] To explain further, Figure 1A A diagram is presented illustrating a perspective view of a temperature sensor 30 for use with an electric motor according to an embodiment of the present disclosure. Figure 1B It's a picture. Figure 1A Schematic diagram of different views of a temperature sensor. Figure 1C It's a picture. Figure 1A FIG. 1 is an illustration of a cross-sectional view of a temperature sensor. Figure 1D It's a picture. Figure 1A FIG. 1 is an exploded cross-sectional view of a temperature sensor.

[0019] like Figures 1A to 1D As shown, the temperature sensor 30 includes a housing 1, a plunger 2, a cover 3, a movable electrical connector 4, a connector 5, an environmental seal 6, a spring 7, and a plunger cover 8 having a thermal sensor 70 having a thermal interface material (TIM). Figure 1A-Figure 1D In the example of , the housing 1 is generally cylindrical, having a top surface, a bottom surface, and a generally cylindrical side wall extending between the top surface and the bottom surface. In the exemplary temperature sensor 30, the mounting tabs 14 extend outwardly from the side wall of the housing. The mounting tabs 14 are shown as including a through hole formed therein. For example, the through hole can accommodate the shaft of a fastener (e.g., a bolt, etc.) to secure the temperature sensor 30 to a motor housing or other mounting structure. The housing 1 also includes a neck portion 16 extending from the bottom surface. The neck portion 16 of the housing 1 defines an opening 15 into the interior volume of the housing 1. The shape and arrangement of the housing 1 are merely examples. In other examples, the housing 1 may not be cylindrical, may have mounting tabs other than the two mounting tabs 14, may omit mounting tabs, the neck portion 16 may be longer or shorter (or omitted), etc.

[0020] In this exemplary embodiment, the plunger 2 is at least partially disposed in the housing 1 and extends through the neck portion 16 to a terminal end spaced apart from the bottom surface of the housing 1. As further detailed herein, the plunger 2 can be moved relative to the housing 1 to achieve contact of the thermal sensor 70 with the hairpin of the stator winding of the electric motor, thereby sensing the temperature of the hairpin regardless of the position of the hairpin. The spring 7 provides an axial force to maintain the thermal sensor 70 in contact with the monitored hairpin. Moving the position of the thermal sensor 70 provides reliable temperature sensing despite relatively large tolerances associated with the hairpin stator windings, as further detailed herein. In a specific embodiment, the plunger 2 and spring 7 can slide axially within the housing 1 and be secured by a bayonet lock.

[0021] The connector 5 can facilitate connection, such as electrical connection, of the temperature sensor 30 to one or more external systems (not shown). For example, but not limited to, the connector 5 can have one or more pins and / or one or more sockets (e.g., for receiving pins) to facilitate connection with the external system. The connector 5 is electrically coupled to the lead 40 disposed in the volume of the housing 1 via the connection device 11. More specifically, in Figure 1D In the example, a portion of the housing 1 is removed to expose the volume. In the example, the housing 1 may include a cover 3 or Figure 1D The top portion of the example is removed.

[0022] like Figure 1DAs best shown in , the temperature sensor 30 includes a thermal sensor 70. One or more leads 60 are electrically connected to the thermal sensor 70. One or more leads 60 are electrically coupled to a connector 10, which is coupled to a lead 40 in the housing 1. The thermal sensor is disposed in an axial opening extending through the plunger 2. The thermal sensor 70 can be arranged adjacent to the bottom of the plunger 2. In some examples, the thermal sensor 70 can be secured in the plunger 2 via a clip. The clip can be a spring clip or other mounting device that is at least partially resilient, deformable and / or deflectable. In examples, the clip can facilitate reliable and accurate contact of a stator winding hairpin or other feature to be monitored by the thermal sensor 70. In other embodiments, a clip is not used and the spring 7 provides sufficient axial force on the plunger 2 to achieve contact between the thermal sensor 70 and the monitored hairpin.

[0023] For assembly, the spring 7 and plunger 2 are axially inserted into the opening 15 defined by the neck portion 16, as described above. Once inserted, the spring 7 contacts the end spaced from the bottom surface of the housing 1 and provides an axial force against the plunger 2. The assembly also includes coupling one or more electrical connectors (10, 4, 40, 60) within the temperature sensor 30, such that the thermal sensor 70 is electrically coupled to the connector 5, which is configured for connection to an external system.

[0024] The thermal sensor 70 can be positioned within the plunger cover 8 and overmolded with a thermal interface material (TIM). In this example, a preload spring 7 ensures proper contact between the plunger cover 8 and the electric motor stator windings to achieve fast response time and accurate readings. Continuing with this example, the plunger cover 8 is inserted into the housing 1 for thermal decoupling from the stator cooling medium. The signal is transmitted through the removable electrical connector 4 and the sensor seal is ensured by the environmental seal 6. The design also allows high accuracy through air gap decoupling of the environment of the thermal sensor and thermal decoupling via the thermal sensor and the electric motor cooling oil. In a particular embodiment, the temperature sensor 30 may also include redundant sensing elements. For example, the redundant sensing elements may be a negative temperature coefficient (NTC) thermistor and a positive temperature coefficient (PTC) or two NTC thermistors.

[0025] To explain further, Figure 2 is a flow chart illustrating an implementation of a method for assembling a temperature sensor device according to an embodiment of the present disclosure. Figure 2 The method includes axially inserting 202 a plunger into an opening defined by a neck portion of a housing. For example, Figure 1A-Figure 1D The plunger 2 in the housing 1 can be inserted into the opening 15 of the housing 1. Figure 2In an example of the present invention, the housing is configured for coupling to an electric motor, and the plunger is movable relative to the housing to position the thermal sensor relative to the electric motor.

[0026] Figure 2 The method also includes coupling 204 one or more electrical connectors within the temperature sensor such that the thermal sensor is electrically coupled to a connector configured for connection to an external system. Figures 1A to 1D In the exemplary temperature sensor 30 of , the thermal sensor 70 is coupled to the connector 5 via the electrical connectors (electrical connector 10 , electrical connector 4 , lead 60 , lead 40 ).

[0027] As will be appreciated from the foregoing, aspects of the present disclosure provide a temperature sensing mechanism that allows accurate temperature sensing in electric motors, even in the presence of relatively large tolerances associated with features to be measured, such as hairpins, etc. In an example, the present disclosure achieves consistent and reliable temperature readings between the sensing element and the stator winding hairpins, which simplifies the motor control scheme and achieves a significant reduction in system-level cost (durability, ease of assembly, and reliability of the motor).

[0028] All orientations and arrangements of the components shown herein are used only by way of example. Further, it will be appreciated by those of ordinary skill in the relevant art that in alternative embodiments, the functions of several elements may be performed by fewer elements or a single element. Similarly, in some embodiments, any functional element may perform fewer or different operations than those described with respect to the illustrated embodiments. Moreover, functional elements that are illustrated as different for the purpose of illustration may be incorporated into other functional elements in a particular embodiment.

[0029] Although the subject technology has been described with respect to embodiments, it will be readily appreciated by those skilled in the art that various changes and / or modifications may be made to the subject technology without departing from the spirit or scope of the subject technology. For example, each claim may be dependent from any or all claims in a multi-dependency manner, even if such claims were not originally claimed for protection.

[0030] The advantages and features of the present disclosure can be further described by the following statements:

[0031] 1. A temperature sensor comprising: a housing configured to be fixed relative to an electric motor; a plunger disposed in the housing; and a thermal sensor disposed in the plunger, wherein the plunger is movable relative to the housing to position the thermal sensor relative to the electric motor.

[0032] 2. The temperature sensor of statement 1 further comprising a spring coupled to the plunger to provide an axial force on the plunger that causes the plunger to move translationally to effect contact of the thermal sensor with a stator winding hairpin of the electric motor.

[0033] 3. The temperature sensor of statement 1 or 2, further comprising a static sensor environmental seal coupled to the housing.

[0034] 4. A temperature sensor according to any of statements 1-3, wherein the static sensor environmental seal comprises at least one of one or more rubber seals and a plastic weld / adhesive.

[0035] 5. A temperature sensor according to any one of statements 1 to 4, wherein the thermal sensor is positioned within the plunger cap.

[0036] 6. Temperature sensor according to any of statements 1 to 5, wherein the plunger cap is inserted into the housing for thermal decoupling from the stator medium of the electric motor.

[0037] 7. A temperature sensor according to any one of statements 1-6, wherein the thermal sensor is overmolded by a thermal interface material.

[0038] 8. A temperature sensor according to any one of statements 1-7, further comprising redundant sensing elements.

[0039] 9. A temperature sensor according to any of statements 1-8, wherein the redundant sensing element comprises a negative temperature coefficient (NTC) thermistor and a positive temperature coefficient (PTC) or two thermistors.

[0040] 10. A temperature sensor according to any of statements 1-9, wherein the redundant sensing element comprises two negative temperature coefficient (NTC) thermistors.

[0041] 11. A temperature sensor according to any of statements 1-10, further comprising a connector configured for coupling to an external system, the connector being coupled to the thermal sensor via an electrical connector.

[0042] 12. A method for assembling a temperature sensor having a housing, a plunger, and a thermal sensor, the method comprising: axially inserting the plunger into an opening defined by a neck portion of the housing, wherein the housing is configured for connection to an electric motor, and the plunger is movable relative to the housing to position the thermal sensor relative to the electric motor; and connecting one or more electrical connectors within the temperature sensor so that the thermal sensor is electrically connected to a connector configured for connection to an external system.

[0043] 13. The method of statement 12 wherein the temperature sensor further comprises a spring coupled to the plunger to provide an axial force on the plunger, the axial force causing the plunger to move translationally to effect contact of the thermal sensor with a stator winding hairpin of the electric motor.

[0044] 14. The method of statement 12 or 13, wherein the temperature sensor further comprises a static sensor environmental seal coupled to the housing.

[0045] 15. The method of any of statements 12-14, wherein the static sensor environmental seal comprises at least one of one or more rubber seals and a plastic weld / adhesive.

[0046] 16. A method according to any of statements 12-15, wherein the thermal sensor is positioned within the plunger cap.

[0047] 17. A method according to any of statements 12-16, wherein the plunger cap is inserted into the housing for thermal decoupling from the stator medium of the electric motor.

[0048] 18. The method of any of statements 12-17, wherein the thermal sensor is overmolded with a thermal interface material.

[0049] 19. A method according to any of statements 12-18, wherein the temperature sensor further comprises redundant sensing elements.

[0050] 20. The method of any of statements 12-19, wherein the temperature sensor further comprises a connector configured for coupling to an external system, the connector being coupled to the thermal sensor via an electrical connector.

[0051] One or more embodiments may be described herein by means of method steps for illustrating the execution of specific functions and their relationships. For ease of description, the boundaries and order of these functional building blocks and method steps have been arbitrarily defined herein. As long as the specific functions and relationships are properly performed, alternative boundaries and orders can be defined. Therefore, any such alternative boundaries or orders are within the scope and spirit of the claims. In addition, for ease of description, the boundaries of these functional building blocks are arbitrarily defined. As long as certain important functions are properly performed, alternative boundaries can be defined. Similarly, flow chart blocks can also be arbitrarily defined herein to illustrate certain important functions.

[0052] To the extent used, the flow diagram block boundaries and sequence could have been otherwise defined and still perform the certain significant functionality. Such alternate definitions of functional building blocks and flow diagram blocks and sequences are thus within the scope and spirit of the claims.

[0053] It can be understood from the foregoing description that modifications and changes can be made in various embodiments of the present invention without departing from the true spirit of the present invention. The description in this specification is for illustrative purposes only and should not be interpreted as limiting. The scope of the present invention is limited only by the language of the appended claims.

Claims

1. A temperature sensor, comprising: a housing configured to be fixed relative to the electric motor; a plunger disposed in the housing; as well as A thermal sensor is disposed in the plunger, wherein the plunger is movable relative to the housing to position the thermal sensor relative to the electric motor.

2. The temperature sensor of claim 1 , further comprising a spring coupled to the plunger to provide an axial force on the plunger, the axial force causing the plunger to move translationally to effect contact of the thermal sensor with a stator winding hairpin of the electric motor. 3 . The temperature sensor of claim 1 , further comprising a static sensor environmental seal coupled to the housing.

4. The temperature sensor according to claim 3, wherein: The static sensor environmental seal includes at least one of one or more rubber seals and a plastic weld / adhesive.

5. The temperature sensor according to claim 1, wherein: The thermal sensor is positioned within the plunger cap.

6. The temperature sensor according to claim 5, wherein: The plunger cap is inserted into the housing to be thermally decoupled from a stator medium of the electric motor.

7. The temperature sensor according to claim 1, wherein: The thermal sensor is overmolded with a thermal interface material.

8. The temperature sensor of claim 1, further comprising redundant sensing elements.

9. The temperature sensor according to claim 8, wherein: The redundant sensing element includes a negative temperature coefficient (NTC) thermistor and a positive temperature coefficient (PTC) or two NTC thermistors.

10. The temperature sensor according to claim 8, wherein: The redundant sensing element includes two negative temperature coefficient (NTC) thermistors.

11. The temperature sensor of claim 1, further comprising a connector configured for coupling to an external system, the connector coupled to the thermal sensor via an electrical connector.

12. A method of assembling a temperature sensor, the temperature sensor having a housing, a plunger, and a thermal sensor, the method comprising: axially inserting the plunger into an opening defined by a neck portion of the housing, wherein the housing is configured to be coupled to an electric motor and the plunger is movable relative to the housing to position the thermal sensor relative to the electric motor; and One or more electrical connectors are coupled within the temperature sensor such that the thermal sensor is electrically coupled to a connector configured for connection to an external system.

13. The method according to claim 12, wherein: The temperature sensor further includes a spring coupled to the plunger to provide an axial force on the plunger that causes the plunger to move translationally to effect contact of the thermal sensor with a stator winding hairpin of the electric motor.

14. The method according to claim 12, wherein: The temperature sensor further includes a static sensor environmental seal coupled to the housing.

15. The method according to claim 14, wherein: The static sensor environmental seal includes at least one of one or more rubber seals and a plastic weld / adhesive.

16. The method according to claim 12, wherein: The thermal sensor is positioned within the plunger cap.

17. The method according to claim 16, wherein: The plunger cap is inserted into the housing to be thermally decoupled from a stator medium of the electric motor.

18. The method according to claim 12, wherein: The thermal sensor is overmolded with a thermal interface material.

19. The method according to claim 12, wherein: The temperature sensor further includes a redundant sensing element.

20. The method according to claim 12, wherein: The temperature sensor further includes a connector configured for coupling to an external system, the connector being coupled to the thermal sensor via an electrical connector.

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