Insulation Arrangement

Abstract

To provide an insulation arrangement that meets the requirements for use in voltage ranges up to 1000 volts and achieve sufficient creepage and air paths to comply with international standards and specifications.SOLUTION: An isolation device for a stator (1) of an electric motor having a plurality of stator coils (2), and each coil separation portion (3) is arranged between adjacent stator coils (2), and a connection between a coil separation portion connector (4) and an annular upper coil separation portion connector (5) in which the ends of the coil separation portions (3) are respectively connected via annular lower coils is implemented as a positive latching connection in combination with an electrically insulating material connection.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an insulation arrangement for a stator of an electric motor, the motor having a number of stator coils which are electrically insulated from one another. Depending on the voltage range for which the motor is designed, different requirements are placed on the electrical insulation of the individual coils with respect to one another. [Background technology]

[0002] A field of application for the insulating arrangement according to the invention is, for example, electric motors for driving refrigerant compressors of closed refrigerant systems, such electric motors being used in motor vehicles, in particular in refrigerant compressors of motor vehicle air conditioning systems. Due to the high voltages up to 1000V, the requirements for electric refrigerant compressors are very high. The creepage paths and the air paths between the two phases and between the non-voltage metallic parts are implemented according to many international standards. Due to the small installation space required to realize the motor / stator, special measures are required to realize the corresponding insulation material system with regard to the required insulation adjustments.

[0003] An air path is the direct distance through the air between two conductive parts, such as two coils. The air path is further defined as the distance from a conductive part to a metal part that does not have voltage, for example a stator core. In contrast, a creepage path is the current conduction path across a surface that accumulates over operating time. It specifies the shortest path on a surface between conductive parts or to the next non-voltage metal part. Electric motors operating in the voltage range of about 400 volts have significantly shorter air and creepage paths. Meeting the requirements of electric motors in the voltage range up to 1000 volts therefore means doubling or even significantly increasing these typical distances. Meanwhile, especially in mobility applications such as automotive air conditioning systems, a compact design of components is essential.

[0004] In the prior art, the stator coils of electric motors of refrigerant compressors are already electrically insulated by axially mounted coil separators. However, disk-shaped axially arranged coil separators do not solve the problems of increased creepage distances and air paths in extra-high voltage applications up to 1000 volts. An insulating arrangement for an electric motor of an electric compressor is known from DE 10 200 63 33 56. This insulating arrangement is provided for an electric motor with a stator core of the type described at the beginning. According to this construction of the stator core, the electric wires are wound on coil carriers extending radially inward from the inner circumference of a stator ring with an inner flange formed at the head end to form coils, and between adjacent coils there are intermediate spaces, which experts call stator grooves. In these intermediate spaces of the coils arranged radially on the inner circumference of the stator, respective coil separators in the form of plate-shaped parts are arranged, which extend radially inward from the inner circumference of the stator and axially between the axial end faces of the stator.

[0005] A special feature of these coil separators is that in cross section perpendicular to their longitudinal direction they have an inwardly directed Y-shape, with each fork end of the Y defining an intermediate space between adjacent coils on the axially longitudinal sides of the opposing inner flanges of the coil carrier. In the stator groove, the coil separator is held in a pressed position by elastic deformation. The axially longitudinal sides of the leg ends of the Y press against the inner surface of the stator ring, and the head ends press against the axially longitudinal sides of the opposing inner flanges of the coil carrier of the stator core.

[0006] Also, the known coil separators are relatively complicated to manufacture and install due to their Y-shaped cross-sectional shape. Moreover, it has been shown that simply pressing the coil separator against the stator core components is insufficient to eliminate potential current paths for leakage currents. Thus, gaps remain between aligned adjacent components of the stator arrangement, with the corresponding risk of creepage paths and undesired current flows. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] German Patent Application Publication No. 102019112534 Summary of the Invention [Problem to be solved by the invention]

[0008] It is an object of the present invention to provide an insulating arrangement which meets the requirements for use in the voltage range up to 1000 volts whilst providing sufficient creepage distances and air paths to comply with international standards and specifications. This object is achieved by the subject matter and methods according to the independent claims. Further developments are given in the dependent claims. [Means for solving the problem]

[0009] The object of the invention is in particular achieved by an insulating arrangement for a stator of an electric motor having a plurality of stator coils, in which respective coil separators are arranged between adjacent stator coils and are connected at their ends via an annular lower coil separator connector and an annular upper coil separator connector, the connections of the coil separators to the coil separator connectors being embodied as positive latch connections in combination with electrical insulating material connections.

[0010] The concept of the present invention is that an improvement in the insulation effect in extra-high voltage applications cannot be achieved by simply pressing two parts together to eliminate possible paths for leakage currents. The nature of a mechanical connection means that a gap remains between the two connected parts as a rule. In order to eliminate possible paths for leakage currents, a material connection must be established between the mechanically connected parts. That is, for example, insulating parts placed next to each other are glued, soldered, welded or vulcanized to each other in order to eliminate the creepage current paths and establish the corresponding air paths according to international standards.

[0011] The design solution to this problem is to close the potential path, also known as the creepage path, by bonding the connections of adjacent components, resulting in a structure that meets international standards for creepage current flow. Material connection in critical areas by pouring or gluing is an additional measure to avoid poor creepage paths. By using coil separators in combination with coil separator part connectors, the air path between the two coils is selected to be correspondingly larger than the direct distance between the coil wires or the distance from the coil to the non-voltage metal part in accordance with the requirements of internationally valid standards, so that the requirements of international standards can be met.

[0012] The material connection is made with a suitable casting material or adhesive, such as epoxy resin. Due to the crown-shaped coil separator connector, the creepage path length meets the required ISO alignment and in some cases is higher than the required international standard. Structurally, the concept of the present invention is realized in that the coil separators are designed to be connected at their ends to the upper coil separator connector and the lower coil separator connector, respectively, in a positive and materially mating manner.

[0013] The upper and lower coil separator connectors are advantageously formed in the axial direction in a crown-shaped, cylindrical section having a sawtooth extension. The coil isolation connector, also called a crown, is designed to ensure sufficient air and creepage passages to the rotating assembly of the rotor and shaft. To ensure a proper press fit at the slot opening, the slot separator is constructed with a certain oversize, and once the coil separator, also called a slot separator, is placed in place during installation, the press fit ensures that the coil separator does not move substantially during installation and handling during operation. After the coil separation parts are attached, the upper and lower coil separation part connectors are placed on the stator and connected to the coil separation parts.

[0014] After assembly of other components necessary for the insulation system, but not essential to the invention, the stator is vacuum pressure impregnated to establish material connections at all contact areas between the stator seals, coil isolation, and coil isolation connectors. The insulation arrangement design of the three basic parts, the coil separator, the upper coil separator connector, and the lower coil separator connector, and their material connections enlarge the air paths and creepage paths. Through the material connections, the critical air paths and creepage paths are completely eliminated, and the other paths are enlarged to meet the requirements of the voltage level at which the motor operates in the corresponding application cases.

[0015] According to the present invention, the teeth front of the stator seal is designed by adding an upper coil separation connector and a lower coil separation connector so as to ensure a structurally ideal winding condition. After the stator is released from the winding machine, the adhesive connection between the contact areas is established in a proper manner, and then the upper and lower coil separator connectors are placed on top to increase the air and creepage paths. Particularly preferably, the coils are electrically insulated from each other over their entire axial length by using a suitable material to establish a material connection to the coil separator, such that no current flows from one coil to the other or from one coil to the stator core inside between the upper coil separator connector and the lower coil separator connector.

[0016] Therefore, the only path remaining for potential creepage and corona is through the top of the coil separator connector, which is carried out at its respective length according to international requirements. The coil separator connector is advantageously formed cylindrically with a sawtooth axially extending guide for the coil separator. It is particularly advantageous if the coil separator is provided with a guide receiving area in the end area facing the coil separator connector. The coil separator preferably has a latch portion receptacle and the coil separator connector has a corresponding latch portion, the latch connection being formed by radial action.

[0017] Advantageously, the latching connection is formed by a latching part receptacle on the coil separator and a latching lug as the latching part on the coil separator connector, and furthermore, the coil separator connector is formed with a guide groove for axial guidance. Advantageously, the latching lugs are formed as webs and the latching portion receivers are formed as corresponding grooves in the adjacent components. The adhesive connections for establishing the material connections between the parts of the thermal insulation arrangement are preferably realised with epoxy resin. The embodiment of a press fit between the guide part of the coil separator connection and the guide part receiving area of ​​the coil separator is particularly preferred. Preferably, an increased contact area is formed between the guide parts for a larger adhesive area.

[0018] The object of the present invention is further achieved by a method for mounting an insulating arrangement on a stator of an electric motor, in particular an electric motor of an electric compressor, in which plate-shaped coil separators are axially positioned at their ends between a lower coil separator connector and an upper coil separator connector, respectively, thereby entering into a latched connection, characterized in that an electrically insulating material is introduced into the contact areas between the plate-shaped coil separators and the lower coil separator connector and the upper coil separator connector, which material forms a material connection between the plate-shaped coil separators and the lower coil separator connector and the upper coil separator connector.

[0019] According to this concept, a material connection is formed from an electrically insulating material, so that the material connection according to the invention is always embodied as being electrically insulating. The electrical insulating material is preferably introduced by a vacuum pressure process method for producing the material connection. Further details, features and advantages of the inventive design will become apparent from the following description of exemplary embodiments which refer to the accompanying drawings. [Brief description of the drawings]

[0020] [Figure 1] FIG. [Diagram 2] FIG. [Diagram 3] A stator coil having adjacent coil separators. [Figure 4] 1 is a vertical cross-sectional view of a coil separation portion. [Diagram 5] FIG. [Figure 6] 1 is an insulation arrangement in exploded view representation. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] FIG. 1 is a perspective view of an insulation arrangement with two coil separators. [Figure 10] FIG. 13 is a diagram showing the insulation layout when the device is installed. [Figure 11] The stator is arranged in an insulated manner. [Figure 12] FIG. 2 is a perspective view of the insulation arrangement with three main parts. [Figure 13] This is the upper coil separation connector. [Figure 14] This is the lower coil separation connector. [Figure 15] This is the coil separation section. [Figure 16] 13 is a detail view of the coil separation section and the coil separation section connector. [Figure 17] 13 is a detail of the coil separation section connector and the coil separation section.

[0021] 1-5 show one embodiment of a prior art insulation arrangement typically designed for electric motors in the voltage range up to about 400 volts. The stator 1 is provided with various stator coils 2 on its circumferential side, and the stator coils 2 are electrically insulated from one another by coil separators 3. The coil separators 3 are arranged axially in the longitudinal direction on the circumferential side and prevent the individual coils and non-current-carrying metal parts from contacting each other. In the illustrated example, twelve stator coils 2 are arranged at equal distances on the circumference of the substantially cylindrical stator 1 and are electrically insulated from one another by the twelve coil separators 3.

[0022] Figures 3, 4 and 5 show details of the prior art design: in Figure 3, the stator coil 2 is represented with adjacent coil separators 3 on either side, in Figure 4 the coil separators 3 are shown in a longitudinal section of the stator 1, and in Figure 5 the coil separators 3 are shown in a plan view, with the T-shaped cross section of the coil separators 3 visible according to the prior art.

[0023] Figures 6, 9, 10 and 12 each show an insulating arrangement according to the invention, consisting of a number of coil separators 3 and a lower coil separator connector 4 and an upper coil separator connector 5 bundling the two ends of the coil separators. These figures are shown in perspective views, partly exploded, or partly or completely assembled.

[0024] 9, the upper and lower coil separation portion connectors 4, 5 are further characterized as each having a guide portion 6 that imparts a respective crown-like appearance to the cylindrical design of the coil separation portion connectors 4, 5 through the sawtooth design of the guide portion 6. As shown in FIG. 15, the guide portion 6 is formed to correspond to the guide portion receiving area 7 of the coil separation portion 3 such that in the installed position, the guide portions 6 of the coil separation portion connectors 4, 5 face each other.

[0025] 7, 8 and 11 show the stator 1 in a perspective view seen obliquely from below and above, respectively. It should be mentioned that the coil separator connectors 4, 5, also called crowns, are not fixed in specific dimensions and change from application to application when the design of the stator is changed. The function of the coil separator 3 is similar to that of the prior art. However, it is specially structurally adapted for connection to the coil separator connectors 4, 5. After the stator 1 leaves the winding machine station during installation, the components of the insulating arrangement are installed on the stator 1, the installation order being unimportant. As an example, the coil separator 3 is placed on the stator 1 first, after which the lower coil separator connector 4 and the upper coil separator connector 5 are installed.

[0026] The individual elements of the insulating arrangement are provided with a suitable adhesive which bonds the contact surfaces between the three components and the stator 1 so that the contact surfaces are bonded to each other and to the stator 1 over their entire surface, thereby fulfilling the insulation requirements.

[0027] In FIG. 13, the upper coil separation connector 5 is shown in a perspective view. The basic shape of the upper coil separation connector 5 is a cylindrical ring embodied as a dodecagon with 12 corners. At the corners, guide parts 6 are arranged as sawtooth-shaped axial expansions of the crown. Guide grooves 10 for the coil separation part 3, which form a press fit with the coil separation part 3, are formed at the corners. Between the guide parts 6, contact surface widening areas 11 for a large-area bonding area are formed, which increases the robustness of the structure. The guide parts 6 with the guide grooves 10 of the upper coil separation connector 5 have latch lugs as latch parts 9 in their upper regions corresponding to the latch part receivers 8 of the coil separation part 3 shown in FIG. 15.

[0028] In Fig. 14, the lower coil separator connector 4 is shown in a perspective view. Here, the sawtooth guide portion 6 faces upwards. Meanwhile, the guide groove 10 for receiving and guiding the coil separator 3 creates a press fit and facilitates the installation of the insulating arrangement. A latch lug is arranged as a latch portion 9 in the lower region of the guide portion 6, corresponding to the lower latch portion receiver 8 of the coil separator 3 in Fig. 15.

[0029] 15 shows the coil separation part 3, with latch part receivers 8 at the top and bottom of both ends. These correspond to the latch parts 9 of the lower coil separation part connector 4 and the upper coil separation part connector 5. In addition, guide part receiver regions 7 that receive the sawtooth guide parts 6 of the lower coil separation part connector and the upper coil separation part connector are shown.

[0030] In Fig. 16 the connection of the coil separator 3 to the upper coil separator connector 5 is shown in detail and enlarged. The upper coil separator connector 5 is shown as a sawtooth extension of the guide 6, which shows that a guide receiving area 7 is formed on the coil separator 3 corresponding to the guide 6. The guide receiving area 7 receives the guide 6. In the case of a radially inwardly directed movement for mounting, the coil separator 3 engages at its end in a guide groove 10 of the upper coil separator connector 5 which is provided with a latching portion receiving portion 8. This results in a latching connection between the latching lug 9 of the upper coil separator connector 5 and the correspondingly formed latching portion receptacle 8 on the coil separator 3.

[0031] 17 shows the connection situation after the coil separator 3 is initially connected to the lower coil separator connector 4 and the upper coil separator connector 5. The guide portions 6 on the upper and lower coil separator connectors 4, 5 are oriented towards each other and are attached to and connected to the coil separator 3 by their respective guide portion receiving areas 7. The guide grooves 10 on the upper and lower coil separator connectors 4, 5 combine with corresponding areas on the coil separator 3 to form a moderately loaded press-fit connection already during installation, prior to the actual latch connection. [Explanation of symbols]

[0032] 1 Stator 2 Stator coil 3 Coil separation section 4 Lower coil separation connector 5 Upper coil separation connector 6 Guide section 7 Guide receiving area 8 Latch receptacle 9 Latch section 10 Guide groove 11 Contact surface widening area

Claims

1. An insulation device for a stator (1) of an electric motor having a plurality of stator coils (2), comprising: An isolation device characterized in that each coil separation portion (3) is arranged between adjacent stator coils (2), the ends of the coil separation portions (3) are connected via an annular lower coil separation portion connector (4) and an annular upper coil separation portion connector (5), and the connection between the coil separation portion (3) and the coil separation portion connectors (4, 5) is realized as a latch connection in combination with a connection using an adhesive that is an electrically insulating material.

2. 2. The device according to claim 1, characterized in that the coil separator connector (4, 5) is formed cylindrically with a sawtooth-shaped axially extending guide portion (6) for the coil separator (3).

3. 3. An isolation device according to claim 1, wherein the coil separator (3) has a guide receiving area (7) in an end area facing the coil separator connectors (4, 5).

4. The coil separation portion (3) has a latch portion receptacle (8), The coil separation connector (4, 5) has a latch portion (9) corresponding to the latch portion receptacle (8), 3. An isolation device according to claim 1, characterized in that the latching connection is made with radial action.

5. The latch connection includes a latch receptacle (8) on the coil separator (3); and a latching portion (9) embodied as a latching lug on said coil separator connector (4, 5), 3. An isolation device according to claim 1 or 2, characterized in that a guide groove (10) for axial guidance of the coil separator (3) is additionally formed on the coil separator connector (4, 5).

6. The latch portion (9) is formed as a web, 5. The isolation device according to claim 4, wherein the latch portion receptacle (8) is formed as a groove to correspond to the latch portion (9).

7. An insulating device as described in claim 1 or 2, characterized in that the adhesive connection between the coil separation portion (3) and the coil separation portion connectors (4, 5) is realized with epoxy resin.

8. 3. The isolation device according to claim 2, wherein the guides (6) of the coil separator connectors (4, 5) and the guide receiving areas (7) of the coil separator (3) are press-fitted together.

9. 3. An isolation device according to claim 2, characterized in that a contact surface widening region (11) for a larger adhesive area is formed between the guide parts (6).

10. A method for assembling an insulating device as described in claim 1 or 2 in a stator of an electric motor, in particular an electric motor of an electric compressor, characterized in that each plate-shaped coil separator is axially positioned so as to enter into a latch connection at its end between a lower coil separator connector and an upper coil separator connector, and an electrically insulating material is introduced into the contact areas between the coil separator and the lower coil separator connector and the upper coil separator connector, and the electrically insulating material forms a physical connection between the coil separator and the lower coil separator connector and the upper coil separator connector.

11. The method of claim 10, wherein the electrically insulating material is introduced by a vacuum pressure processing method.

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