Rotating shaft assembly, motor and robot

Abstract

The present invention provides a rotating shaft assembly, a motor and a robot, comprising a rotating shaft and a brake for braking the rotating shaft, wherein the brake comprises a fixed electromagnetic part and an armature capable of moving along the axial direction of the rotating shaft, wherein the electromagnetic part can drive the armature to move along the axial direction of the rotating shaft, and the rotating shaft comprises a magnetic isolation section, wherein the magnetic isolation section is provided with a magnetic isolation part, and in the axial direction of the rotating shaft, the armature always covers a portion of the magnetic isolation part, and the electromagnetic part covers a portion of the magnetic isolation part, so as to solve the technical problem of magnetic leakage of the brake along the rotating shaft in the prior art.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and in particular relates to a rotating shaft assembly, a motor and a robot. Background Art

[0002] With the continuous development of industrial automation, the application fields of robots are becoming more and more extensive. Servo motors serve as the power source of robots. Robot joints are driven by servo motors to operate and stop. When the joints need to be in operation, the brake stator and armature of the servo motor are attracted to disengage the friction plate from the armature, realizing the brake opening action and allowing the motor to rotate normally; when the joints need to be in a stopped state, the brake armature is released, causing the armature to press the friction plate and thus "hold" the motor shaft, allowing the joints to maintain their current position.

[0003] The brake generates magnetic flux through the stator coil to control the armature attraction. However, when the stator coil of the brake is energized, a portion of the magnetic flux will close along the rotating shaft, which is called "magnetic leakage", resulting in an increase in the attraction voltage, reducing the reliability and life of the brake.

[0004] How to reduce the magnetic flux leakage along the rotating shaft when the brake is energized is a technical problem that needs to be solved urgently. Summary of the Invention

[0005] Therefore, the present invention provides a rotating shaft assembly, a motor and a robot, which can solve the technical problem of magnetic flux leakage along the rotating shaft of the brake in the prior art.

[0006] In the first aspect, the present invention provides a rotating shaft assembly, comprising a rotating shaft and a brake for braking the rotating shaft, the brake comprising a fixed electromagnetic part and an armature capable of moving along the axial direction of the rotating shaft, the electromagnetic part can drive the armature to move along the axial direction of the rotating shaft, the rotating shaft comprises a magnetic isolation section, the magnetic isolation section is provided with a magnetic isolation part, in the axial direction of the rotating shaft, the armature always covers a portion of the magnetic isolation part, and the electromagnetic part covers a portion of the magnetic isolation part.

[0007] In some embodiments, the magnetic isolation section is provided with an accommodation position, and the magnetic isolation component is provided in the accommodation position. In the projection in the axial direction of the rotating shaft, the maximum radial dimension of the outer surface of the magnetic isolation component in the rotating shaft is L, and the outer cylindrical diameter of the rotating shaft is D, 0.98D≤L≤D.

[0008] In some embodiments, the axial direction of the rotating shaft is the length direction, the length of the electromagnetic part is b, the length of the armature is a, when the electromagnetic part is energized, the length of the magnetic isolation part covered by the electromagnetic part is e, and the length of the magnetic isolation part covered by the armature is c; c≥a / 2, e≥b / 2.

[0009] In some embodiments, the length of the magnetic isolation member is g, the distance between the electromagnetic portion and the armature is h, and g≥3h.

[0010] In some embodiments, there are n accommodating positions and magnetic isolation members in one-to-one correspondence, and the plurality of magnetic isolation members uniformly surround the rotating shaft; in the circumferential direction of the rotating shaft, the distance between two adjacent magnetic isolation members is k. n is a natural number greater than 1, and D is the diameter of the rotating shaft.

[0011] In some embodiments,

[0012] In some embodiments, the magnetic isolation member is an annular block, the accommodation position is an annular groove matching the annular block, the depth of the annular groove is L, and 0.01D≤L≤0.15D.

[0013] In some embodiments, on a cross section passing through the axis of the magnetic isolation member, the inner surface of the magnetic isolation member is an arc surface with a middle portion convex toward the rotating shaft.

[0014] In a second aspect, the present invention provides a motor, comprising the aforementioned rotating shaft assembly, wherein the rotating shaft is the rotating shaft of the motor.

[0015] In a third aspect, the present invention further provides a robot comprising the motor.

[0016] By providing the aforementioned magnetic shielding member, the present application prevents or minimizes the magnetic flux generated by the electromagnetic unit from forming along the axial direction of the rotating shaft. This significantly reduces magnetic flux leakage from the rotating shaft, lowers the voltage required to drive the armature, improves the power density and reliability of the brake, and, when the rotating shaft assembly is used in a motor, also increases the life of the motor. By designing the inner surface of the magnetic shielding member as an arc with a central portion convex toward the rotating shaft, the structural strength of the rotating shaft is increased without compromising magnetic shielding performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. The drawings described below are merely exemplary. Those skilled in the art can, without inventive effort, derive other implementation drawings based on the provided drawings.

[0018] Figure 1 1 is a schematic diagram of the motor structure according to an embodiment of the present invention;

[0019] Figure 2 is an exploded schematic diagram of a shaft assembly according to an embodiment of the present invention;

[0020] Figure 3is a schematic diagram of the rotating shaft assembly of an embodiment of the present invention when assembled together;

[0021] Figure 4 This is a schematic diagram showing the size markings of various structures of the rotating shaft assembly when the winding is energized according to an embodiment of the present invention;

[0022] Figure 5 1. It is an exploded view of the rotating shaft and the magnetic isolation member when the magnetic isolation member is in a ring shape according to an embodiment of the present invention;

[0023] Figure 6 is a schematic diagram of a rotating shaft from a first perspective when the ring-shaped magnetic isolation member according to an embodiment of the present invention is set in an accommodating position;

[0024] Figure 7 is a schematic diagram of the rotating shaft from a second perspective when the ring-shaped magnetic isolation member according to an embodiment of the present invention is set in the accommodation position;

[0025] Figure 8 1 is an axial schematic diagram of a ring-shaped magnetic isolation member according to an embodiment of the present invention;

[0026] Figure 9 is a radial cross-sectional view of a ring-shaped magnetic isolation member according to an embodiment of the present invention;

[0027] Figure 10 2. Schematic diagram of the rotating shaft when the magnetic isolation member of the embodiment of the present invention is in a minor arc shape;

[0028] Figure 11 This is the process of the embodiment of the present invention Figure 10 Axial cross-sectional view of the intermediate magnetic component;

[0029] Figure 12 2. A schematic diagram of a rotating shaft when the magnetic isolation member is rectangular in an embodiment of the present invention;

[0030] Figure 13 This is the process of the embodiment of the present invention Figure 12 Axial cross-sectional view of the intermediate magnetic component;

[0031] Figure 14 2 is a schematic diagram of a rotating shaft when the magnetic isolation member is in a triangular shape according to an embodiment of the present invention;

[0032] Figure 15 This is the process of the embodiment of the present invention Figure 14 Axial cross-sectional view of the intermediate magnetic component;

[0033] Figure 16 1 is a schematic diagram of magnetic flux distribution in a rotating shaft assembly provided with a magnetic isolation member according to an embodiment of the present invention;

[0034] Figure 17 This is an embodiment of the present invention Figure 4 Schematic diagram of the magnetic flux density of the magnetic isolation segment when g=3h;

[0035] Figure 18 This is an embodiment of the present invention Figure 4 Schematic diagram of the magnetic flux density of the magnetic isolation segment when g=2h;

[0036] Figure 19 This is an embodiment of the present invention Figure 4 Schematic diagram of the magnetic flux density of the magnetic isolation segment when g=1h;

[0037] Figure 20 is a graph showing the relationship between the magnetic leakage rate M and g / h according to an embodiment of the present invention;

[0038] Figure 21 The magnetic flux leakage rate M of the embodiment of the present invention is The relationship curve diagram between ;

[0039] Figure 22 This is a schematic diagram of the magnetic density at a position on the rotating shaft corresponding to the magnetic isolation end of the present application when no magnetic isolation member is provided in the prior art;

[0040] Figure 23 This is a schematic diagram of the magnetic flux path when the shaft assembly of the prior art is not provided with a magnetic isolation member;

[0041] Figure 24 This is a diagram of the magnetic flux distribution on the rotating shaft when the electromagnetic part of the prior art is energized;

[0042] Figure 25 This is a schematic diagram of the motor structure without a magnetic isolation member in the prior art;

[0043] Figure 26 This is a schematic diagram of a rotating shaft assembly without a magnetic isolation member in the prior art;

[0044] Figure 27 It is the existing technology Figure 20 First-person exploded view;

[0045] Figure 28 It is the existing technology Figure 20 The second perspective exploded view;

[0046] The accompanying drawings are:

[0047] 1. Rotating shaft; 2. Electromagnetic unit; 201. Iron core; 202. Winding; 3. Armature; 4. Magnetic shield; 5. Hub; 501. Friction plate; 601. Guide post; 602. Spring; 603. Connecting key; 604. Bearing; 605. End cover; 606. Housing; 607. Encoder; 7. Receiving position; DETAILED DESCRIPTION

[0048] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0050] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0051] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0052] Combine Figure 1-21The present invention provides a rotating shaft assembly, including a rotating shaft 1 and a brake for braking the rotating shaft 1, the brake including a fixed electromagnetic part 2 and an armature 3 capable of moving along the axial direction of the rotating shaft 1, the electromagnetic part 2 can drive the armature 3 to move along the axial direction of the rotating shaft 1, the rotating shaft 1 includes a magnetic isolation section, and the magnetic isolation section is provided with a magnetic isolation part 4. In the axial direction of the rotating shaft 1, the armature 3 always covers a portion of the magnetic isolation part 4, and the electromagnetic part 2 covers a portion of the magnetic isolation part 4.

[0053] Existing technologies such as Figure 22-28 As shown in the figure, there is no magnetic shielding member on the shaft. The magnetic field generated by the stator coil can form a magnetic flux along the shaft, resulting in magnetic leakage. Due to magnetic leakage, the voltage required to provide a certain electromagnetic force to drive the armature to move is higher. Correspondingly, if the magnetic leakage is reduced, the voltage required to provide the same electromagnetic force can be reduced. In other words, due to magnetic leakage, the power density of the brake is lower under the same size. Please refer to the attached Figure 1-3 and Figure 16 The present application sets the magnetic isolation member 4, which makes the magnetic field generated by the electromagnetic part 2 (the electromagnetic part 2 includes the winding 202 and the iron core 201) unable to or rarely form a magnetic flux along the axial direction of the rotating shaft 1. Figure 16 As shown, the magnetic leakage of the shaft 1 is greatly reduced, the voltage required to drive the armature 3 to move is reduced, the power density and reliability of the brake are improved, and when the shaft assembly is applied to the motor, the life of the motor is also increased.

[0054] The magnetic isolation member 4 is made of non-magnetic material. Figure 1-3 As shown, in addition to the electromagnetic part 2 including the winding 202 and the iron core 201, it also includes: a hub 5 fixed on the rotating shaft 1, and the hub 5 is fixed to the rotating shaft 1 via a connecting key 603. The size of the connecting key 603 can meet the structural strength requirements, especially the length of the connecting key 603; a friction plate 501 is fixedly provided on the hub 5, and a guide column 601 is provided between the armature 3 and the iron core 201. The armature 3 slides along the guide column 601 and is restricted from circumferential rotation by the guide column 601. A spring 602 is also provided between the armature 3 and the iron core 201. When the winding 202 is energized, the armature 3 is separated from the friction plate 501 and moves away from the friction plate 501 under the action of the electromagnetic part 2, and the spring 602 is squeezed in the process of the armature 3 moving away from the friction plate 501; after the winding 202 is de-energized, the armature 3 moves toward the friction plate 501 under the action of the spring 602 and squeezes the friction plate 501, thereby braking the rotating shaft 1.

[0055] Preferably, Figure 1-3As shown, the magnetic isolation section is provided with an accommodation position 7, and the magnetic isolation component 4 is arranged in the accommodation position. In the projection in the axial direction of the rotating shaft 1, the maximum radial dimension of the outer surface of the magnetic isolation component 4 in the rotating shaft 1 is L, and the outer cylindrical surface diameter of the rotating shaft 1 is D, 0.98D≤L≤D.

[0056] In the projection of the axial direction of the rotating shaft 1, 0.98D≤L≤D, that is, in this way, the magnetic isolation member 4 will not interfere with the armature 3, and the magnetic isolation member 4 will not have an adverse effect on the gas flow between the outer peripheral surface of the rotating shaft 1 and the inner peripheral surface of the brake, which is conducive to gas flow, improves heat dissipation efficiency, and avoids excessively high brake temperature and reduced braking performance.

[0057] Preferably, Figure 4 As shown, the axial direction of the rotating shaft 1 is the length direction, the length of the electromagnetic part 2 is b, the length of the armature 3 is a, and when the electromagnetic part 2 is energized, the length of the magnetic isolation part 4 covered by the electromagnetic part 2 is e, and the length of the magnetic isolation part 4 covered by the armature 3 is c; c≥a / 2, e≥b / 2.

[0058] like Figure 4 As shown, c and e are too small, and the effect of isolating the magnetic flux generated by the electromagnetic part 2 in the rotating shaft 1 is poor. Through experiments, c≥a / 2, e≥b / 2 are made, which effectively isolates the magnetic flux generated by the electromagnetic part 2 in the rotating shaft 1.

[0059] Preferably, Figure 4 As shown, the length of the magnetic isolation member 4 is g, the distance between the electromagnetic part 2 and the armature 3 is h, and g≥3h.

[0060] Figure 22 The magnetic flux distribution diagram on the rotating shaft when there is no magnetic isolation member; the present application is provided with a magnetic isolation member 4. When g is too small, the magnetic isolation member 4 has a poor effect on the magnetic flux isolation. Figure 17-Figure 19 , Figure 20 It can be clearly seen that when g≥3h, the magnetic flux in the shaft 1 can be well reduced.

[0061] Preferably, Figure 4 As shown, there are n accommodating positions and magnetic isolation members 4 in one-to-one correspondence, and multiple magnetic isolation members 4 evenly surround the rotating shaft 1; in the circumferential direction of the rotating shaft 1, the distance between two adjacent magnetic isolation members 4 is k, n is a natural number greater than 1, and D is the diameter of the rotating shaft 1 .

[0062] like Figure 7 As shown, πD is the circumference of the shaft 1, and nk is the length of the area not covered by the magnetic shielding member 4 along the circumferential direction of the shaft 1; Figure 21 As shown, when When the magnetic field is not covered by the magnetic isolation member 4, the area is small, which can effectively isolate the magnetic field generated by the electromagnetic part 2 and reduce magnetic leakage.

[0063] Preferably,

[0064] Due to the provision of the accommodation position 7, if k=0, multiple accommodation positions will be interconnected along the circumferential direction of the shaft 1 to form an annular groove. The annular groove will cause the cross-sectional area of ​​the magnetic isolation section to be greatly reduced, and the maximum radial dimension passing through the axis of the shaft 1 will be reduced, resulting in a decrease in the bending moment resistance of the shaft 1, reducing the bearing capacity of the shaft 1 and not being conducive to the smooth rotation of the shaft 1. It can not only effectively reduce magnetic flux leakage, but also ensure the structural strength of the rotating shaft 1.

[0065] Preferably, Figure 5-8 As shown, the magnetic isolation member 4 is an annular block, the accommodation position is an annular groove matching the annular block, the depth of the annular groove is L, 0.01D≤L≤0.15D.

[0066] The shape of the magnetic isolation member 4 can be various, such as Figure 10-11 The inferior arc of Figure 12-13 The class rectangle in Figure 14-15 The triangle-like shape in . Preferably, Figure 5 、 Figure 8 and Figure 9 As shown, the magnetic isolation member 4 is in a ring shape.

[0067] 0.01D≤L≤0.15D, which not only prevents the magnetic isolation member 4 from being too thin in the radial direction of the rotating shaft 1 and causing a decrease in magnetic isolation performance, but also prevents the magnetic isolation member 4 from being too thick and causing insufficient structural strength of the rotating shaft 1.

[0068] The diameter d of the bottom wall of the annular groove is D-2L. In order to make the diameter of the outer circular surface of the ring-shaped magnetic isolation component 4 be D after the magnetic isolation component 4 is installed, considering the possible gap between the inner circular surface of the magnetic isolation component 4 and the bottom wall of the annular groove after assembly, the diameter of the inner circular surface is greater than d, that is, the thickness of the annular magnetic isolation component 4 is less than L. When installing the magnetic isolation component 4, the magnetic isolation component 4 can be interference installed in the annular groove and glued at the same time.

[0069] Preferably, Figure 9 As shown, on the cross section passing through the axis of the magnetic isolation member 4 , the inner surface of the magnetic isolation member 4 is an arc surface with the middle portion convex toward the rotating shaft 1 .

[0070] Furthermore, when considering magnetic flux leakage, if Figure 17-18As shown, the magnetic flux path of the magnetic field in the rotating shaft 1 is a cross-section along the axis of the ring-shaped magnetic isolation member 4. The inner surface of the magnetic isolation member 4 is a raised arc surface in the middle, and the accommodating position is a groove adapted to the raised arc surface. Under the premise of ensuring the isolation of magnetic flux and reducing magnetic leakage, the inner surface of the accommodating position is avoided from having sharp corners, thereby avoiding sharp corner stress and improving the structural strength of the rotating shaft 1.

[0071] In a second aspect, the present invention provides a motor, comprising the aforementioned rotating shaft assembly, wherein the rotating shaft 1 is the rotating shaft 1 of the motor.

[0072] like Figure 1 As shown, the motor further includes a bearing 604, an end cover 605, a housing 606, an encoder 607, etc.

[0073] Because the brake generates radial electromagnetic force on the rotating shaft 1, it also reduces the life of the bearing 604 supporting the rotating shaft 1. A motor equipped with the above-described rotating shaft assembly significantly reduces brake leakage, improves brake power density, and enhances brake reliability and the life of the motor using it, while ensuring brake output torque and connection reliability.

[0074] The magnetic field generated by the brake has little effect on the bearing 604, which is beneficial to improving the overall life of the motor; when the motor is a servo motor, the voltage required by the brake is small, the magnetic field strength generated is low, and the impact on the encoder 607 is also low.

[0075] In a third aspect, the present invention further provides a robot comprising the motor.

[0076] It is easy for those skilled in the art to understand that, under the premise of no conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0077] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and variations without departing from the technical principles of the present invention, and such improvements and variations shall also be considered within the scope of protection of the present invention.

Claims

1. A rotating shaft assembly, comprising a rotating shaft (1) and a brake for braking the rotating shaft (1), wherein the brake comprises a fixed electromagnetic part (2) and an armature (3) capable of moving along the axial direction of the rotating shaft (1), wherein the electromagnetic part (2) is capable of driving the armature (3) to move along the axial direction of the rotating shaft (1), and wherein: The rotating shaft (1) comprises a magnetic isolation section, wherein the magnetic isolation section is provided with a magnetic isolation member (4); in the axial direction of the rotating shaft (1), the armature (3) always covers a portion of the magnetic isolation member (4), and the electromagnetic part (2) covers a portion of the magnetic isolation member (4).

2. The shaft assembly according to claim 1, wherein: The magnetic isolation section is provided with an accommodation position (7), the magnetic isolation member (4) is arranged in the accommodation position (7), and in the projection in the axial direction of the rotating shaft (1), the maximum radial dimension of the outer surface of the magnetic isolation member (4) in the rotating shaft (1) is L, the outer diameter of the rotating shaft (1) is D, and 0.98D≤L≤D.

3. The shaft assembly according to claim 2, wherein: The axial direction of the rotating shaft (1) is the length direction, the length of the electromagnetic part (2) is b, the length of the armature (3) is a, and when the electromagnetic part (2) is energized, the length of the magnetic isolation part (4) covered by the electromagnetic part (2) is e, and the length of the magnetic isolation part (4) covered by the armature (3) is c; c≥a / 2, e≥b / 2.

4. The shaft assembly according to claim 3, wherein: The length of the magnetic isolation member (4) is g, the interval between the electromagnetic part (2) and the armature (3) is h, and g≥3h.

5. The shaft assembly according to claim 2, wherein: There are n accommodating positions (7) and magnetic isolation members (4) in one-to-one correspondence, and the plurality of magnetic isolation members (4) uniformly surround the rotating shaft (1); in the circumferential direction of the rotating shaft (1), the distance between two adjacent magnetic isolation members (4) is k, and nk / πD≤0.4; n is a natural number greater than 1, and D is the diameter of the rotating shaft (1).

6. The shaft assembly according to claim 5, characterized in that: 0.1≤nk / πD.

7. The shaft assembly according to any one of claims 2 to 6, characterized in that: The magnetic isolation member (4) is an annular block, and the accommodating position (7) is an annular groove matching the annular block. The depth of the annular groove is L, and 0.01D≤L≤0.15D.

8. The shaft assembly according to claim 1, wherein: On a cross section passing through the axis of the magnetic isolation member (4), the inner surface of the magnetic isolation member (4) is an arc surface with the middle portion convex toward the rotating shaft (1).

9. A motor, characterized in that: The invention comprises the rotating shaft assembly according to any one of claims 1 to 8, wherein the rotating shaft is a rotating shaft (1) of a motor.

10. A robot, characterized in that: Including the motor according to claim 9.

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