Cover element for an end shield of an electric motor and electric motor

Abstract

The invention relates to a cover element (14) for an end shield (12) of an electric motor (10), wherein when the cover element (14) is installed on the end shield (12), an outer side (24) of the cover element (14) faces surroundings of the end shield (12), and wherein an inner side (22) of the cover element (14) faces a transmitter circuit board (20) for a transmitter (18) of the electric motor (10), wherein the inner side (22) has a geometric cooling structure (26) for cooling the transmitter circuit board (20). The invention further relates to an electric motor (10).

Description

[0001] Description

[0002] Cover element for a bearing plate of an electric motor and electric motor

[0003] The invention relates to a cover element for a bearing plate of an electric motor, wherein an outer side of the cover element, when the cover element is installed on the bearing plate, faces an environment of the electric motor / bearing plate, and wherein an inner side of the cover element faces a sensor board for a sensor of the electric motor. Furthermore, the invention relates to an electric motor having at least one housing with a cover element.

[0004] In electric motors, particularly permanent magnet electric motors or servo motors, circuit boards with sensors and electronics for optical encoders are mounted on a side opposite the customer mounting side, which can also be referred to as NDE (non-drive ending). There are various designs for different motor sizes. The components on this circuit board generate heat themselves due to electrical losses and can only be operated up to certain limit temperatures that are significantly below the permissible winding temperatures of the motors. In addition to the heating from the motor winding, the losses in the integrated encoders lead to an increase in temperature on the circuit boards. The utilization of the motors is therefore limited by reaching the temperature limit of the circuit board components and not by the permissible thermal utilization of the insulation system of the motor winding.

[0005] It is already known from the prior art that in order to keep the thermal load on the circuit boards below the respective permissible temperature limit, an insulating disk, preferably made of thermosetting plastic, is installed between a bearing shield of the electric motor and a cover in order to prevent the heat flow from the motor winding via the housing and bearing shield to the sensor components as much as possible. In addition, the so-called DQ-Con circuit board is connected to the inside of the die-cast aluminum cover by means of a gap filler, which in particular corresponds to a thermally conductive paste, in order to transport the heat loss generated on the circuit boards and in the sensor's own bearings from the circuit board to the cover and then dissipate it to the environment via the outer surface of the cover.For this purpose, the cover must be cooler than the circuit board or thermally decoupled in order to achieve a sufficient temperature gradient for the required heat transfer.

[0006] The object of the present invention is to provide a cover element and an electric motor by means of which improved cooling of a sensor board of the electric motor can be achieved.

[0007] This object is achieved by a cover element and an electric motor according to the independent patent claims. Advantageous embodiments are specified in the subclaims.

[0008] One aspect of the invention relates to a cover element for a bearing plate of an electric motor, wherein an outer side of the cover element, in the installed state of the cover element on the bearing plate, faces an environment of the bearing plate, and wherein an inner side of the cover element faces a sensor board for a sensor of the electric motor.

[0009] It is intended that the inside has a geometric cooling structure for cooling the encoder board.

[0010] In particular, the cover element is designed in such a way that additional geometric elements are formed on the inside, which lead to a significant enlargement of the heat-absorbing surface, for example up to a factor of five compared to the original inner surface. This means, for example, that a so-called gap filler for heat transfer to the cover element is no longer necessary. Improved heat flow and homogeneous heat distribution in the cover element can be achieved, for example, by different wall thicknesses in the cover element. Achieving the most homogeneous heat distribution possible in the cover is important in order to maximize the transfer of heat to the ambient air.

[0011] Thus, the cover element can provide a geometric cooling structure, which enables improved heat dissipation from the encoder board to the environment. This leads to improved cooling of the electric motor and thus enables an increase in the electric motor's performance.

[0012] In particular, passive cooling is provided via the geometric cooling structure. By increasing the heat surface area per unit area of ​​the cover element, more thermal energy can be absorbed by the cover element and then dissipated to the environment, particularly the external environment of the bearing plate or the electric motor.

[0013] The electric motor is preferably designed as a servo motor.

[0014] According to an advantageous embodiment, at least one elevation is formed on the inside as a geometric cooling structure. In particular, the elevation serves to enlarge the corresponding surface area. The elevation can have different geometric structures. For example, the elevation can be substantially cylindrical or triangular. In this way, a geometric cooling structure with an enlarged surface area can be produced in a simple manner. Furthermore, it has proven advantageous if a large number of elevations is formed on the inside. In particular, the large number can have at least two or more elevations. In particular, the elevations can be formed substantially uniformly on the inside. The large number of elevations can increase the surface area of ​​the cover element, as a result of which improved heat dissipation can be achieved.

[0015] A further advantageous embodiment provides that the at least one elevation is substantially cylindrical. In particular, the elevation thus protrudes cylindrically from the inside toward the encoder board, in particular substantially in a longitudinal direction of the electric motor, wherein the longitudinal direction runs substantially parallel to a rotational axis of the electric motor. This structure makes it possible to increase the surface area, thereby enabling improved heat dissipation from the encoder board.

[0016] Furthermore, it has proven advantageous if the geometric cooling structure is designed as at least one cooling ring. In particular, the cooling structure thus runs in a ring-shaped manner along the cover element. For this purpose, it can further be provided that, for example, the cylindrical elevations are additionally formed in at least some regions of the cooling ring. This makes it possible to increase the surface area accordingly, thereby achieving improved heat dissipation.

[0017] It is also advantageous if the geometric cooling structure has a large number of cooling rings. This allows the surface area to be increased and improved heat dissipation to be achieved.

[0018] A further advantageous embodiment provides that the plurality of cooling rings is designed as nested cooling rings. In particular, the cooling rings are essentially designed as concentric rings. For example, the cooling rings can then be designed to engage one another and thus, in particular, have different radii. A center point of the rings can, for example, essentially coincide with an axis of rotation of the electric motor relative to the arranged cover element. This makes it possible to create a geometric cooling structure in a simple manner, which enables improved heat dissipation.

[0019] A further advantageous embodiment provides for the cover element and the geometric cooling structure to be formed as a single piece. For example, the cover element can be made of aluminum. The geometric cooling structure can then also be made of aluminum. Thus, the cover element with the geometric cooling structure can be created in a single manufacturing process. This allows for a simpler manufacturing process for the cover element. Furthermore, improved heat dissipation can be achieved based on the aluminum.

[0020] According to a further advantageous embodiment, a heat-conducting coating can additionally be formed on the geometric cooling structure. The heat-conducting coating can serve, in particular, to increase the surface area and also to better absorb the heat from the sensor board. This allows for improved heat transfer to the geometric cooling structure, which in turn improves heat dissipation from the electric motor.

[0021] It is also advantageous if the heat-conducting coating is a copper coating or a paint finish. For example, the paint finish can be in the form of a black paint finish. This makes it possible to coat the cover element, in particular the geometric cooling structure, in a simple manner and to achieve improved heat dissipation. It has also proven advantageous if the geometric cooling structure is designed as a three-dimensionally printed structure on the inside. In particular, the three-dimensionally printed structure can therefore be designed with the largest possible surface area on the inside. This means that a lot of radiant heat can be transferred from the circuit board to the inner surface of the cover element on the inside.

[0022] A further advantageous embodiment provides that the geometric cooling structure has a receiving area for the sensor board. In particular, the sensor board is essentially semicircular. In the area where the semicircular sensor board is arranged essentially in the direction of the cover element, the geometric structure has a corresponding receiving area which serves to accommodate the sensor board. Thus, the geometric cooling structure can be arranged very close to the sensor board, whereby the geometric cooling structure can absorb the heat more effectively.

[0023] It has also proven advantageous if the geometric cooling structure has a reduced longitudinal extension in the region of the receiving area. In particular, the longitudinal extension can be considered in the direction of the shaft / axis of the encoder or the electric motor, for example. The longitudinal extension is then reduced in the region of the receiving area. In other words, the receiving area has a shorter longitudinal extension than the non-receiving area.

[0024] A further aspect of the invention relates to a bearing plate with a cover element according to the preceding aspect.

[0025] Furthermore, the invention also relates to an electric motor having at least one bearing plate with a cover element according to the preceding aspect, a sensor, and a sensor board. Advantageous embodiments of the cover element are to be regarded as advantageous embodiments of the bearing plate and the electric motor.

[0026] In an advantageous embodiment of the electric motor, the sensor shaft of the sensor has a swirl structure. In particular, a contour can be formed on the motor shaft or sensor shaft, which leads to swirling of the internal air and thus to forced convection. This significantly increases the heat transfer coefficients at the surfaces, allowing a significantly larger amount of heat to be transferred from the circuit board to the inner surface of the cover element.

[0027] In particular, the last aspect of the invention can also be considered an independent aspect of the invention. In other words, it can be provided that, independently of the cover element with the geometric cooling structure, the electric motor has the encoder shaft / motor shaft with the swirl structure. This serves, in particular, to ensure that swirl can be generated within the electric motor even without a geometric cooling structure, thereby enabling improved heat dissipation based on convection.

[0028] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identity are included.

[0029] Further features of the invention emerge from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown in the figures can be encompassed by the invention not only in the respectively specified combination, but also in other combinations. In particular, the invention can also encompass embodiments and combinations of features which do not have all the features of an originally formulated claim. Furthermore, the invention can encompass embodiments and combinations of features which go beyond the combinations of features set out in the references to the claims or deviate from them.

[0030] Showing:

[0031] FIG 1 is a schematic partial view of an embodiment of an electric motor;

[0032] FIG 2 shows a further schematic perspective view of an electric motor;

[0033] FIG 3 is a schematic sectional view of a further embodiment of an electric motor;

[0034] FIG 4 is a schematic plan view of an embodiment of a cover element of an electric motor;

[0035] FIG 5 is a schematic perspective view of the cover element according to FIG 4;

[0036] FIG 6 shows a further schematic plan view of a further embodiment of a cover element;

[0037] FIG 7 is a schematic perspective view according to an embodiment of the cover element according to FIG 6;

[0038] FIG 8 is a schematic perspective view of a swirl structure for an electric motor; and

[0039] FIG 9 is a schematic sectional view of a further embodiment of an electric motor.

[0040] The invention is explained in more detail below with reference to specific exemplary embodiments and associated schematic drawings. In the figures, identical or functionally equivalent elements may be provided with the same reference numerals. The description of identical or functionally equivalent elements may not necessarily be repeated for different figures.

[0041] FIG. 1 shows a schematic perspective view of an embodiment of an electric motor 10. The electric motor 10 has a bearing plate 12. The bearing plate 12 in turn has a cover element 14. The motor itself, a sensor shaft 16 or motor shaft 38 (FIG. 3), a sensor 18 (FIG. 2) and a sensor board 20 (FIG. 2) are formed in an interior space of a housing (not shown) and adjacent to the bearing plate 12. Furthermore, an outer side 24 of the cover element 14 is shown.

[0042] An electric motor 10 can in particular be referred to as a special electric motor which allows the control of the angular position of its motor shaft as well as the rotational speed and acceleration. In particular, the electric motor 12 is designed as a servomotor. This has in particular an electric motor which is additionally equipped with a sensor / encoder 18 for position determination. The rotational position of the motor shaft 38 determined by the sensor is continuously transmitted to control electronics which are usually installed outside the actual motor and which, in a control loop, regulates the movement of the motor according to one or more adjustable setpoints - such as the setpoint angular position of the shaft or the setpoint speed.

[0043] FIG. 2 shows a schematic perspective view of the electric motor 10 without the cover element 14, thus showing the interior of the electric motor 10. In particular, the encoder shaft 16, the encoder 18, and the encoder board 20 are shown. FIG. 2 shows, in particular, an encoder mounting for the encoder 18 with its own bearing and coupling.

[0044] FIG. 3 shows a schematic sectional view of an embodiment of an electric motor 10. FIG. 3 shows, in particular, a sensor attachment for a sensor 18 with direct attachment to the motor shaft 38 of the electric motor 10. Furthermore, an insulating disk 40 is shown.

[0045] FIG 4 shows a schematic plan view of an embodiment of the cover element 14.

[0046] The cover element 14 is designed in particular for the bearing plate 12. In the present exemplary embodiment, the cover element 14 has an inner side 22. The inner side 22, in turn, faces the encoder board 20 in the installed state.

[0047] FIG. 4 shows, in particular, that the inner side 22 has a geometric cooling structure 26 for cooling the encoder board 20. In the following exemplary embodiment, it is shown, in particular, that at least one elevation 28, in particular a plurality of elevations 28, is provided. In the present exemplary embodiment, the elevations 28 are essentially cylindrical. It is understood that the elevations 28 may also have other shapes, for example, pyramid-shaped or the like.

[0048] In particular, it is thus shown that the cover element 14 is designed such that it has the additional geometric cooling structure 26 on the inner side 22, which leads to a significant enlargement of the heat-absorbing surface. This makes it possible, for example, to dispense with a so-called gap filler for heat transfer to the cover element 14. An improved heat flow and homogeneous heat distribution in the cover element 14 are achieved by different wall thicknesses in the cover element 14. Achieving the most homogeneous heat distribution possible in the cover element 14 is important in order to maximize the transfer of the amount of heat to the ambient air, in particular on the outer side 24.

[0049] FIG 5 shows a schematic perspective view according to an embodiment of the cover element 14 from FIG 4 . In particular, the elevations 28 are shown in perspective here. In a further exemplary embodiment, it can be provided that a heat-conducting coating 30 can be provided on the geometric cooling structure 26. The heat-conducting coating 30 can be, for example, a copper coating or a paint, in particular a black paint. In particular, it can thus be provided that the geometric cooling structure 26 is provided and, in addition, a very highly conductive copper coating or a black paint with a very high degree of absorption is applied to the inner side 22 in order to optimize heat absorption even further.

[0050] Furthermore, it can be provided in particular that the geometric cooling structure 26 and the cover element 14 are formed in one piece, for example in one piece from aluminum.

[0051] FIG. 6 shows a further schematic plan view of an embodiment of the cover element 14. In the present case, it is shown in particular that the geometric cooling structure 26 can have at least one cooling ring 32. In particular, it can be provided that a plurality of cooling rings 32 is provided, wherein in particular the cooling rings can be designed to lie one inside the other. Furthermore, FIG. 6 shows that the elevations 28, in the present case in particular the cylindrical elevations 28, can also be formed on the cooling rings 32.

[0052] The cooling rings 32, and in the present embodiment also the elevations 28, can be formed as a three-dimensional printed structure on the inner side 22. This allows a large amount of radiant heat to be transferred from the circuit board 20 to the inner surface of the cover element 14 on the inner side 22.

[0053] FIG. 7 shows a schematic perspective view of the cover element 14 according to FIG. 6. In the following exemplary embodiment, it is shown in particular that the geometric cooling structure 26 has a receiving area 34 for the sensor board 20. In particular, the receiving area 34 is designed as an area with a reduced longitudinal extent L.

[0054] In other words, it can be seen that the receiving area 34 is formed in an area facing the observer, which has a reduced longitudinal extent L than the area behind it. In particular, the encoder board 20 can be arranged in this receiving area 34, then in the assembled state of the electric motor 10.

[0055] FIG. 8 shows a schematic perspective view of a swirl structure 36. The swirl structure 36 serves, in particular, for additional cooling. FIG. 9, in turn, shows the swirl structure 36 in an installed state in the electric motor 10.

[0056] A further addition can thus be provided for a corresponding contour as a swirl structure 36 to be attached to the rotating motor or encoder shaft, which leads to swirling of the internal air and thus to forced convection. This significantly increases the heat transfer coefficients at the surfaces and allows a significantly larger amount of heat to be transferred from the encoder board 20 to the inner surface of the cover element 14. In particular, this aspect can be considered both in conjunction with the geometric cooling structure 26 and independently of the geometric cooling structure 26.

[0057] In particular, the cover element 14 is designed such that additional geometric elements are formed on the inside, which lead to a significant enlargement of the heat-absorbing surface, for example up to a factor of five compared to the original inner surface. This means, for example, that a so-called gap filler for heat transfer to the cover element is no longer necessary. An improved heat flow and homogeneous heat distribution in the cover element can be achieved, for example, by different wall thicknesses in the cover element. Achieving the most homogeneous heat distribution possible in the cover is important in order to maximize the transfer of heat to the ambient air.

[0058] In particular, Figs. 1 to 9 show that the geometric cooling structure 26 can be provided via the cover element 14, which enables improved heat dissipation from the encoder board 20 to the environment. This leads to improved cooling of the electric motor 10 and thus to an increase in the performance of the electric motor 10.

[0059] In particular, passive cooling is thus provided via the geometric cooling structure 26. By increasing the heat surface area per unit area of ​​the cover element 14, more thermal energy can be absorbed by the cover element 14 and then dissipated to the environment, in particular to an external environment of the housing 12 or the electric motor 10.

Claims

Patent claims 1. Cover element (14) for a bearing plate (12) of an electric motor (10), wherein an outer side (24) of the cover element (14) in the installed state of the cover element (14) on the bearing plate (12) faces an environment of the bearing plate (12), and wherein an inner side (22) of the cover element (14) faces a sensor board (20) for a sensor (18) of the electric motor (10), characterized in that the inner side (22) has a geometric cooling structure (26) for cooling the sensor board (20).

2. Cover element (14) according to claim 1, characterized in that on the inner side (22) at least one elevation (28) is formed as a geometric cooling structure (26).

3. Cover element (14) according to claim 2, characterized in that a plurality of elevations (28) are formed on the inner side (22).

4. Cover element (14) according to one of claims 2 or 3, characterized in that the at least one elevation (28) is substantially cylindrical.

5. Cover element (14) according to one of the preceding claims, characterized in that the geometric cooling structure (26) is designed as at least one cooling ring (32).

6. Cover element (14) according to claim 5, characterized in that the geometric cooling structure (26) has a plurality of cooling rings (32).

7. Cover element (14) according to claim 6, characterized in that the plurality of cooling rings (32) are designed as nested cooling rings (32).

8. Cover element (14) according to one of the preceding claims, characterized in that the cover element (14) and the geometric cooling structure (26) are formed in one piece.

9. Cover element (14) according to one of the preceding claims, characterized in that a heat-conducting coating (30) is additionally formed on the geometric cooling structure (26).

10. Cover element (14) according to claim 9, characterized in that the heat-conducting coating (30) is a copper coating or a paint coating.

11. Cover element (14) according to one of the preceding claims, characterized in that the geometric cooling structure (32) is formed as a three-dimensionally printed structure on the inner side (22).

12. Cover element (14) according to one of the preceding claims, characterized in that the geometric cooling structure (26) has a receiving area (34) for the sensor board (20).

13. Cover element (14) according to claim 12, characterized in that in the region of the receiving area (34) the geometric cooling structure (26) has a reduced longitudinal extent (L).

14. Electric motor (10) with at least one bearing plate (12) with a cover element (14) according to one of claims 1 to 13, a sensor (16) and a sensor board (20).

15. Electric motor (10) according to claim 14, characterized in that a swirling structure (36) is formed on a sensor shaft (18) of the sensor (16).

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