Rotating shaft assembly, motor and robot

Abstract

The invention provides a rotating shaft assembly, a motor and a robot, the rotating shaft assembly comprises a rotating shaft and a brake used for braking the rotating shaft, the brake comprises a fixedly arranged electromagnetic part and an armature capable of moving in the axial direction of the rotating shaft, the electromagnetic part can drive the armature to move in the axial direction of the rotating shaft, and the rotating shaft comprises a magnetism isolating section; the magnetic isolation section is provided with a magnetic isolation piece, in the axial direction of the rotating shaft, the armature always covers part of the magnetic isolation piece, the electromagnetic part covers part of the magnetic isolation piece, and therefore the technical problem that in the prior art, a brake leaks magnetism along the rotating shaft can be solved.

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 are 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, thereby opening the brake and allowing the motor to rotate normally. When the joints need to be stopped, the brake armature is released, causing the armature to press the friction plate and "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 part 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 leakage along the rotating shaft when the brake is energized is a technical problem that urgently needs to be solved. 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 leakage of the brake along the rotating shaft in the prior art.

[0006] In a 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 fixedly arranged 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 part of the magnetic isolation part, and the electromagnetic part covers a part of the magnetic isolation part.

[0007] In some embodiments, the magnetic isolation section is provided with a accommodating position, and the magnetic isolation component is arranged in the accommodating 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 interval between the electromagnetic portion and the armature is h, and g≥3h.

[0010] In some embodiments, there are n accommodating positions and magnetic shielding members, and they correspond one to one. The magnetic shielding members uniformly surround the rotating shaft. In the circumferential direction of the rotating shaft, the distance between two adjacent magnetic shielding members is k. n is a natural number greater than 1, and D is the diameter of the 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 above-mentioned shaft assembly, wherein the shaft is the shaft of the motor.

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

[0016] The present application sets the above-mentioned magnetic isolation member, which makes the magnetic field generated by the electromagnetic part unable or rarely forms magnetic flux along the axial direction of the rotating shaft, thereby greatly reducing the magnetic leakage of the rotating shaft, reducing the voltage required to drive the armature to move, and improving the power density and reliability of the brake. When the rotating shaft assembly is applied to the motor, it also increases the life of the motor. By making the inner surface of the magnetic isolation member an arc surface with the middle part protruding toward the rotating shaft, the structural strength of the rotating shaft is increased without reducing the magnetic isolation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. The drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0018] Figure 1 is a schematic diagram of the motor structure of 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 components of an embodiment of the present invention when assembled together;

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

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

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

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

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

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

[0028] Fig.11 The embodiment of the present invention is Fig.10 An axial cross-sectional view of the septum magnetic component;

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

[0030] Fig.13 The embodiment of the present invention is Fig.12 An axial cross-sectional view of the septum magnetic component;

[0031] Fig.14 is a schematic diagram of a rotating shaft when the magnetic isolation member of an embodiment of the present invention is a triangular-shaped member;

[0032] Fig.15 The embodiment of the present invention is Fig.14 An axial cross-sectional view of the septum magnetic component;

[0033] Fig.16 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] Fig.17 The embodiment of the present invention Figure 4 Schematic diagram of the magnetic flux density of the magnetic isolation segment when g=3h;

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

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

[0037] Fig. 20 is a curve diagram showing the relationship between the magnetic leakage rate M and g / h in an embodiment of the present invention;

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

[0039] Fig. 22 It is a schematic diagram of the magnetic density size of the 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] Fig.23 It 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] Fig.24 It is a magnetic flux distribution diagram on the rotating shaft when the electromagnetic part of the prior art is energized;

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

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

[0044] Fig. 27 It is the prior art Fig. 20 First-person exploded view;

[0045] Fig.28 It is the prior art Fig. 20 The second perspective explosion diagram;

[0046] The accompanying drawings are marked as follows:

[0047] 1. Rotating shaft; 2. Electromagnetic part; 201. Iron core; 202. Winding; 3. Armature; 4. Magnetic isolation member; 5. Hub; 501. Friction plate; 601. Guide column; 602. Spring; 603. Connecting key; 604. Bearing; 605. End cover; 606. Casing; 607. Encoder; 7. Accommodation position; DETAILED DESCRIPTION

[0048] The following will be combined with the 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 described embodiments 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 by no means 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 creative work are within the scope of protection of the present invention.

[0049] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the 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 devices or elements 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 contours 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 here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. 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 figure. For example, if the device in the accompanying 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. If not 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] Combination Figure 1-21The present invention provides a rotating shaft assembly, including a rotating shaft 1 and a brake for braking the rotating shaft 1, wherein the brake includes 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 can drive the armature 3 to move along the axial direction of the rotating shaft 1, and the rotating shaft 1 includes a magnetic isolation section, wherein the magnetic isolation section is provided with a magnetic isolation part 4, and 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, and the magnetic field generated by the stator coil can form a magnetic flux along the shaft, resulting in magnetic leakage. Due to magnetic leakage, a larger voltage is required to provide a certain electromagnetic force to drive the armature to move. 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 of brake. Please refer to the attached Figure 1-3 and Fig.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. Fig.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 improved.

[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, the hub 5 is fixed on 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 arranged on the hub 5, a guide column 601 is arranged 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, and a spring 602 is also arranged 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 a receiving position 7, and the magnetic isolation component 4 is arranged in the receiving 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 circumferential 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 component 4 will not interfere with the armature 3, and the magnetic isolation component 4 will not have an adverse effect on the gas flow between the outer circumference of the rotating shaft 1 and the inner circumference of the brake, which is beneficial to the gas flow, improves the 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, and the magnetic flux generated by the electromagnetic part 2 in the rotating shaft 1 is effectively isolated.

[0059] Preferably, Figure 4 As shown, 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.

[0060] Fig. 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 of blocking the magnetic flux. Figure 17-Figure 19 , Fig. 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 a plurality of 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; Fig.21 As shown, when When the magnetic field is not covered by the magnetic shielding member 4, the area is small, which can effectively block 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, which 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 moment resistance of the shaft 1, reducing the bearing capacity of the shaft 1, and not 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 magnetic isolation member 4 can have many shapes, such as Figure 10-11 The inferior arc shape in Figure 12-13 The class rectangle in Figure 14-15 The triangle-like shape in . Preferably, Figure 5 , Figure 8 and Fig. 9 As shown, the magnetic isolation member 4 is in a ring shape.

[0067] 0.01D≤L≤0.15D, which can prevent the magnetic isolation performance from being reduced due to the magnetic isolation member 4 being too thin in the radial direction of the shaft 1 , and can also prevent the structural strength of the shaft 1 from being insufficient due to the magnetic isolation member 4 being too thick.

[0068] The diameter d of the bottom wall of the annular groove is D-2L. In order to make the diameter of the outer circumferential surface of the ring-shaped magnetic isolation component 4 D after the magnetic isolation component 4 is installed, considering the possible gap between the inner circumferential surface of the magnetic isolation component 4 and the bottom wall of the annular groove after assembly, the diameter of the inner circumferential 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 installed in the annular groove with interference fit and glue bonding can be set at the same time.

[0069] Preferably, Fig. 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, 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 component 4. The inner surface of the magnetic isolation component 4 is a raised arc surface in the middle, and the accommodation position is a groove adapted to the raised arc surface. Under the premise of ensuring the isolation of magnetic flux and reducing leakage magnetic flux, sharp corners are avoided on the inner surface of the accommodation position, 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 shaft assembly, wherein the shaft 1 is the 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, and the like.

[0073] Since the brake generates radial electromagnetic force on the rotating shaft 1, the life of the bearing 604 supporting the rotating shaft 1 will also be reduced. The motor provided with the above-mentioned rotating shaft assembly significantly reduces the leakage flux of the brake, improves the power density of the brake, and improves the reliability of the brake and the life of the motor using it while ensuring the output torque of the brake and the reliability of the connection.

[0074] The magnetic field generated by the brake has little effect on the bearing 604, which is beneficial to improving the life of the motor. When the motor is a servo motor, the brake requires a smaller voltage, generates a lower magnetic field strength, and has less effect on the encoder 607.

[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, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0077] The above description is only 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 principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A rotating shaft assembly, comprising a rotating shaft (1) and a brake for braking the rotating shaft (1), the brake comprising a fixedly arranged electromagnetic part (2) and an armature (3) capable of moving along the axial direction of the rotating shaft (1), the electromagnetic part (2) being capable of driving the armature (3) to move along the axial direction of the rotating shaft (1), characterized in that: The rotating shaft (1) comprises a magnetic isolation section, the magnetic isolation section is provided with a magnetic isolation member (4), and 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, characterized in that: The magnetic isolation section is provided with a receiving position (7), the magnetic isolation member (4) is arranged at the receiving 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 circumferential diameter of the rotating shaft (1) is D, and 0.98D≤L≤D.

3. The shaft assembly according to claim 2, characterized in that: 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 shielding member (4) covered by the electromagnetic part (2) is e, and the length of the magnetic shielding member (4) covered by the armature (3) is c; c≥a / 2, e≥b / 2.

4. The shaft assembly according to claim 3, characterized in that: 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, characterized in that: There are n accommodating positions (7) and magnetic shielding members (4) in one-to-one correspondence, and the plurality of magnetic shielding members (4) uniformly surround the rotating shaft (1); in the circumferential direction of the rotating shaft (1), the distance between two adjacent magnetic shielding 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 accommodation 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, characterized in that: 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: It 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: A motor comprising the motor described in claim 9.

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