Torque motor

Abstract

The invention relates to a torque motor (10) comprising a stator (16), a rotor (12), exciter coils arranged on the stator, and permanent magnets (14) arranged on the rotor (12). The exciter coils and the permanent magnets (14) are radially opposite one another, separated by an air gap (24), such that the rotor (12) is able to be set in rotation about a horizontal axis of rotation (26). According to the invention, the rotor (12) is annular and the stator (16) has at least one arc-shaped stator segment (20) in which multiple exciter coils are combined. The at least one stator segment (20) spans an angular range of at most 160 degrees, in particular of at most 135 degrees.

Description

[0001]April 14, 2025 DESCRIPTION Torque Motor TECHNICAL FIELD 5 The invention relates to a torque motor. A torque motor is a multi-pole, electric direct drive. Torque motors have very high torques at relatively low speeds. Torque motors can be used, for example, as direct drives in rotary tables. They can also be used in devices for computer and magnetic resonance tomography. 10 STATE OF THE ART Torque motors can be implemented as external rotors or internal rotors. With an external rotor, the stator is arranged inside and the rotor outside, whereas with an internal rotor, the rotor is arranged inside and the stator outside. 15 External rotors are generally more common, as they provide a higher torque for the same size. Torque motors operate according to the same principle as normal synchronous motors.The permanent magnets are usually glued to the inside of a tubular socket (hollow shaft) forming the rotor. The stator consists of a large number of coils embedded in an iron matrix. These coils are connected in a star configuration and supplied with three-phase current. The respective speed depends on the frequency. Due to the relatively high number of poles, high torque can be achieved at low speeds. 25 In particular, when the torque motor is arranged with a horizontal axis of rotation, as is required, for example, in applications in computer and magnetic resonance imaging, special requirements can arise for the bearings. This can lead to a certain degree of bearing wear, especially when the drive motor is heavy, including any attachments.5 EP 3057209 B1 discloses a corresponding torque motor with a stator and a rotor. Excitation coils are arranged on the stator, while permanent magnets are arranged on the rotor, which are radially opposite the excitation coils across an air gap. By electrically controlling the excitation coils, the rotor can be set in rotation relative to the stator, with the axis of rotation in this case running horizontally. In an internal rotor, the vertically upper half of the stator in the direction of the gravitational force is completely equipped with excitation coils, while the vertically lower half of the stator has no excitation coils. In an internal stator, on the other hand, the vertically lower half of the stator is completely equipped with 15 excitation coils, while the vertically upper half of the stator has no excitation coils.Through this arrangement of the excitation coils, the gravitational force acting on the rotor can be at least partially compensated, so that the bearing load is reduced. DESCRIPTION OF THE INVENTION 20 Starting from this previously known prior art, the object of the invention is to provide an improved torque motor in which the bearing load relief can be adjusted as variably as possible. The torque motor according to the invention is defined by the features of main claim 1. Useful developments of the invention are the subject matter of further claims following this claim. The torque motor according to the invention has a stator with excitation coils and a rotor with permanent magnets. The excitation coils of the stator and the permanent magnets of the rotor are radially opposite each other across an air gap, so that the rotor can be set in rotation about a horizontal axis of rotation. Page 2 of 10 April 14, 2025According to the invention, the rotor is ring-shaped. The stator has at least one circular-arc-shaped stator segment in which several excitation coils are combined. The at least one stator segment spans an angular range of a maximum of 160 degrees, in particular a maximum of 135 degrees. The stator is therefore no longer ring-shaped; rather, the stator comprises at least one circular-arc-shaped stator segment. An arc-shaped segment is easier to assemble, transport, and store, allowing for overall cost-effective production. Furthermore, handling is significantly simplified. The at least one circular-arc-shaped stator segment allows the required motor power to be precisely calculated and adjusted. In principle, even the design of a single stator segment is advantageous.In the case of an internal rotor, the individual stator segment can be arranged in the vertically upper half of the stator in the direction of the gravitational force, so that the weight force (process load) acting on the bearing can be at least partially compensated by the individual stator segment. In the case of an external rotor, the individual stator segment can correspondingly be arranged in the vertically lower half of the stator in the direction 20 of the gravitational force. The stator can preferably comprise several circular arc-shaped stator segments. The individual stator segments can therefore be made smaller, so that assembly and storage can be further simplified. In addition, the individual stator segments can be distributed around the stator 25 in such a way that the weight force acting on the bearing (process load) can be compensated as optimally as possible. The angular range of the at least one stator segment can in principle be freely selected.The individual stator segments each span a multiple of the base motor, allowing individual adaptation to the respective requirements. In particular, the circular-arc-shaped stator segments can each span approximately 45 degrees or 60 degrees. In a first embodiment, with a torque motor designed as an internal rotor, all circular-arc-shaped stator segments can be arranged in the vertically upper half of the stator in the direction of the gravitational force. With a torque motor designed as an external rotor, the stator segments can correspondingly be arranged in the vertically lower half of the torque motor in the direction of the gravitational force. In this way, all stator segments can contribute to balancing the weight force (process load) acting on the bearing, so that maximum balancing of the weight force (process load) is possible.Alternatively, two of the circular-arc-shaped stator segments can be arranged opposite one another. In this case, the stator segments can, for example, be combined into two groups, with the two groups being arranged on either side of the stator. In this case, the weight force acting on the bearing (process load) is not compensated for by the stator segments. However, such compensation is not necessary in all applications. In a particularly advantageous embodiment, the stator has at least one circular-arc-shaped sheet metal segment. Although this sheet metal segment cannot contribute to driving the rotor, it can be used to individually adjust the weight force acting on the bearings (process load). The design of a stator with a circular-arc-shaped sheet metal segment is therefore of independent inventive significance.If the stator is designed with at least one stator segment, the at least one lamination segment and the at least one stator segment can have identical radii. Preferably, the at least one lamination segment can be arranged in the center of the upper half of the stator in the direction of the gravitational force in the case of a torque motor designed as an internal rotor. In the case of a torque motor designed as an external rotor, the at least one lamination segment can be arranged in the vertically lower half of the stator in the direction of the gravitational force. In this way, the lamination segment can optimally contribute to compensating the weight force (process load) acting on the bearing. Alternatively or additionally, the at least one lamination segment can be arranged in the center of the vertically lower half of the stator in the direction of the gravitational force in the case of a torque motor designed as an internal rotor.In a torque motor designed as an external rotor, the at least one lamination segment 10 can be arranged in the vertically upper half of the stator in the direction of the gravitational force. The lamination segment can thus amplify the weight force (process load) acting on the bearing. Such a design can be particularly advantageous if the weight force (process load) is already overcompensated by the rest of the stator. 15 The at least one lamination segment can be arranged between two stator segments. In this case, the at least one lamination segment can border a stator segment on both sides. Alternatively, there can be a certain mutual distance between the at least one lamination segment and at least one of the two adjacent stator segments. 20 Since solid steel would lead to excessive heating of the lamination segment, the at least one lamination segment can consist, in particular, of a layered electrical steel sheet.In order to enable further fine adjustment of the weight force (process load) acting on the bearing, the air gap between the permanent magnets of the rotor and the at least one sheet metal segment can be individually adjustable. As a result, the height of the air gap between the permanent magnets of the rotor and the at least one sheet metal segment can be different from the height of the air gap between the permanent magnets of the rotor and the stator segments. Page 5 of 10 April 14, 2025 Further advantages and features of the invention can be found in the features further specified in the claims and the following exemplary embodiments. BRIEF DESCRIPTION OF THE DRAWINGS The invention is described and explained in more detail below with reference to the exemplary embodiments illustrated in the drawings. They show: Fig. 1 a schematic view of a first embodiment of the torque motor according to the invention, Fig.2 shows a schematic view of a second embodiment of the torque motor according to the invention, FIG. 3 shows a schematic view of a third embodiment of the torque motor according to the invention, FIG. 4 shows a schematic view of a fourth embodiment of the torque motor according to the invention, and FIG. 5 shows a schematic view of a fifth embodiment of the torque motor according to the invention. WAYS OF IMPLEMENTING THE INVENTION A first embodiment of the torque motor 10 according to the invention is shown schematically in FIG. 1. The torque motor 10 has an annular rotor 12 which is provided with permanent magnets 14 in the usual way. The rotor 12 is rotatably mounted relative to the stator 16 in the usual way. This can be done by means of a conventional bearing system, in particular by means of rolling bearings. In the present example, the stator 16 has a single stator segment 20.In the present example, the stator segment 20 spans an angular range of approximately 120 degrees. Several excitation coils (not shown here) are combined in the stator segment 20. The excitation coils are radially opposite the permanent magnets 14 arranged on the rotor 12 across an air gap 24. With suitable electrical control of the excitation coils of the stator segment 20, the rotor 12 can be set in rotation relative to the stator 16 about the axis of rotation 26 running in the horizontal direction via the magnetic fields extending across the air gap 24. In the present example, the torque motor 10 is designed as an internal rotor. The rotor 12 is thus arranged internally.In order to compensate as completely as possible for the weight force (process load) acting on the bearings (not shown here), the stator segment 20 is arranged in the vertically upper half of the stator 16 in the direction of the gravitational force. The stator segment 20 therefore contributes to compensating for the weight force (process load) acting on the bearings. In contrast to the embodiment shown in the drawing, the torque motor according to Fig. 1 could also be designed as an external rotor and thus with the rotor 12 located on the outside. In this case, the stator segment 20 would be arranged in the lower half of the stator 16 in the direction of the gravitational force. A second embodiment of the torque motor 10.2 according to the invention is shown schematically in Fig. 2. The torque motor 10.2 has an annular rotor 12, which is provided with permanent magnets 14 in the usual way. The rotor 12 is rotatably mounted relative to the stator 16.2 in the usual way. The stator 16.2 has, in the present example, a stator segment 20 that spans an angular range of approximately 120 degrees. Since the torque motor 10.2 in the present example is designed as an internal rotor, the individual stator segment 20 is arranged in the center of the vertically upper half of the stator 16.2 in the direction of the gravitational force. This results in overcompensation of the weight force (process load) acting on the bearings in the present example. To counteract this overcompensation, a circular sheet metal segment 30 is arranged as a force relief segment in the center of the vertically lower half of the stator 16.2 in the direction of the gravitational force. The length of the sheet metal segment 30 can be adapted to the required compensating force. A third embodiment of the torque motor 10.3 according to the invention is shown schematically in Fig. 3. The torque motor 10.3 has an annular 5 rotor 12, which is provided with permanent magnets 14 in the usual way. The rotor 12 is rotatably mounted relative to the stator 16.3 in the usual way. In the present example, the stator 16.3 has a total of four identically constructed stator segments 20.3. The four stator segments 20.3 are each identically constructed and in the present example each span an angular range of approximately 10 45 degrees. The stator segments 20.3 are divided into two groups, each with two stator segments 20.3. The two groups are each arranged at the level of the equator 28 of the stator 16.3. As a result, the stator segments 20.3 do not balance the forces acting on the bearings. 15 In the present example, the torque motor 16.3 is designed as an internal rotor.In order to compensate for the weight force (process load) acting on the bearings as completely as possible, a circular arc-shaped sheet metal segment 30.3 is arranged in the center of the vertically upper half of the stator 16.3 in the direction of the gravitational force in this example. The sheet metal segment 30.3 serves as a force relief segment, so that the weight force (process load) acting on the bearings can be compensated for as completely as possible by the sheet metal segment 30.3. The length of the sheet metal segment 30.3 can be adapted to the required balancing force. In this example, the sheet metal segment 30.3 borders on both sides of the adjacent stator segments 20.3. In contrast, a certain distance to the adjacent stator segment 20 could also be present on both sides or one side of the sheet metal segment 30.3 (see also Fig. 4 or 5). In contrast to the embodiment shown in the drawing, the torque motor 10.3 according to Fig.3 can also be designed as an external rotor and thus with an external rotor 12. In this case, the sheet metal segment 30.3 would be arranged in the lower half of the stator 16.3, in the direction of the gravitational force. A fourth embodiment of the torque motor 10.4 according to the invention is shown schematically in Fig. 4. The torque motor 10.4 has an annular rotor 12, which is provided with permanent magnets 14 in the usual way. The rotor 12 is rotatably mounted relative to the stator 16.4 in the usual way. In the present example, the stator 16.4 has a total of two identically constructed stator segments 20.4. The two stator segments 20.4 each span an angular range of approximately 60 degrees and are thus somewhat larger than the stator segments 20.3. The stator segments 20.4 are arranged opposite each other, with both stator segments 20.4 each adjacent to the equator 28 of the stator 16.4.As a result, the two stator segments 20.4 do not balance the forces acting on the bearings.15 In the present example, the torque motor 10.4 is designed as an internal rotor. In order to compensate for the weight force (process load) acting on the bearings as completely as possible, a circular sheet metal segment 30.4 is arranged as a force relief segment in the center of the vertically upper half of the stator 16.4 in the direction of the gravitational force in the present example. The20 length of the sheet metal segment 30.4 can be adapted to the required balancing force. In the present example, the sheet metal segment 30.4 borders on the stator segment 20.4 shown on the left in Fig. 4. However, there is a certain mutual distance between the stator segment 20.4 shown on the right and the sheet metal segment 30.4. 25 In contrast to the embodiment shown in the drawing, the torque motor 10.4 according to Fig.4 can also be designed as an external rotor and thus with an external rotor 12. In this case, the sheet metal segment 30.4 would be arranged in the lower half of the stator 16.4, in the direction of the gravitational force. Page 9 of 10 April 14, 2025 A fifth embodiment of the torque motor 10.5 according to the invention is shown schematically in Fig. 5. The torque motor 10.5 has an annular rotor 12, which is provided with permanent magnets 14 in the usual way. The rotor 12 is rotatably mounted relative to the stator 16.5 in the usual way. 5 In the present example, the stator 16.5 has two identically constructed stator segments 20.4. The stator segments 20.4 are arranged mostly in the vertically upper half of the stator 16.5 in the direction of the gravitational force, but extend somewhat into the vertically lower half of the stator 16.5. Through the stator segments 20.5, this already results in a partial 10 compensation of the weight force acting on the bearings (process load). In the present example, a sheet metal segment 30.4 is arranged as a force relief segment in the center of the vertically upper half of the stator 16.5 in the direction of the gravitational force. In the present example, the sheet metal segment 30.4 has a significantly greater distance from the permanent magnets 14 than the 15 stator segments 20.4. The height 32 of the air gap 24 is thus increased in the area of ​​the sheet metal segment 30.4. Thus, the sheet metal segment 30.4 contributes less to compensating the weight force acting on the bearings (process load) than would be the case with a smaller air gap 24. To counteract overcompensation, a sheet metal segment 30 is arranged as a force relief segment in the center of the vertically lower half of the stator 16.5 in the direction of the 20 gravitational force.The length of the sheet metal segment 30 can be adapted to the required compensating force. In contrast to the embodiment shown in the drawing, the torque motor 10.5 according to Fig. 5 could also be designed as an external rotor and thus with an external rotor 12. In this case, the sheet metal segment 30 would be arranged in the upper half of the stator 16.5, in the direction of the gravitational force, while the stator segment 30.4 and the sheet metal segment 30.4 would be arranged in the lower half of the stator 16.5, in the direction of the gravitational force. Page 10 of 10.

Claims

April 14, 2025 CLAIMS 01. Torque motor (10, 10.2, 10.3, 10.4, 10.5) - with a stator (16, 16.2, 16.3, 16.4, 16.5), 5 - with a rotor (12), - with excitation coils arranged on the stator, - with permanent magnets (14) arranged on the rotor (12), - wherein the excitation coils and the permanent magnets (14) are radially opposite one another via an air gap (24), so that the rotor (12) can be rotated about a horizontal axis of rotation (26), - characterized in that - the rotor (12) is annular, - the stator (16, 16.2, 16.3, 16.4, 16.5) has at least one circular arc-shaped stator segment (20, 20.3, 20.4), in which several excitation coils (15) are combined, - the at least one stator segment (20, 20.3, 20.4) spans an angular range of a maximum of 160 degrees, in particular a maximum of 135 degrees.

02. Torque motor according to claim 1, - characterized in that 20 - the stator (16.3, 16.4, 16.5) comprises a plurality of circular-arc-shaped stator segments (20, 20.3).

03. Torque motor according to claim 1 or 2, characterized in that the circular-arc-shaped stator segments (20.3) each span 45 degrees. Page 1 of 4. April 14, 2025 04. Torque motor according to claim 1 or 2, - characterized in that - the circular-arc-shaped stator segments (20.4) each span 60 degrees. 5 05. Torque motor according to one of the preceding claims, - characterized in that - all circular-arc-shaped stator segments (20) are arranged in the vertically upper half of the stator (16, 16.2) in the direction of the gravitational force in a torque motor designed as an internal rotor, and in the vertically lower half of the stator in the direction of the gravitational force in a torque motor designed as an external rotor.

06. Torque motor according to one of claims 2 to 4, - characterized in that - two of the circular-arc-shaped stator segments (20.3, 20.4) are arranged opposite one another.

07. Torque motor according to the preamble of claim 1 or according to one of the preceding claims, - characterized in that - the stator (16.2, 16.3, 16.4, 16.5) has at least one circular arc-shaped 20 sheet metal segment (30, 30.3, 30.4).

08. Torque motor according to claim 7, characterized in that - the at least one sheet metal segment (30.3, 30.4) is arranged centrally in the vertically upper half of the stator (16.3, 16.4, 16.5) in the case of a torque motor designed as an internal rotor, and in the vertically lower half of the stator in the direction of the gravitational force in the case of a torque motor designed as an external rotor. Page 2 of 4. April 14, 2025 09. Torque motor according to claim 7 or 8, - characterized in that - the at least one sheet metal segment (30) is arranged centrally in the vertically lower half of the stator (16.2, 16.5) in the case of a torque motor designed as an internal rotor, and in the vertically upper half of the stator in the direction of the gravitational force in the case of a torque motor designed as an external rotor.

10. Torque motor according to one of claims 7 to 9, - characterized in that - the at least one sheet metal segment (30, 30.3, 30.4) is arranged between two stator segments (20.3, 20.4).

11. Torque motor according to claim 10, - characterized in that - the at least one sheet metal segment (30.3) borders a stator segment 15 (20, 20.3, 20.4) on both sides.

12. Torque motor according to claim 10, - characterized in that - between the at least one sheet metal segment (30.4) and at least one of the two adjacent stator segments (20.4) a certain mutual distance of 20 is maintained.

13. Torque motor according to one of claims 7 to 12, characterized in that - the at least one sheet metal segment (30, 30.3, 30.4) consists of a layered electrical sheet. Page 3 of 4. April 14, 2025 14. Torque motor according to one of claims 7 to 13, characterized in that - the air gap (24) between the permanent magnets (14) of the rotor (12) and the at least one sheet metal segment (30, 30.3, 30.4) is individually adjustable.

15. Torque motor according to claim 14, characterized in that - the height (24) of the air gap (24) between the permanent magnets (14) of the rotor (12) and the at least one sheet metal segment (30.4) is different from the height (24) of the air gap (24) between the permanent magnets (14) of the rotor (12) and the stator segments (20, 20.3, 20.4). Page 4 of 4

Images