Brake mechanism and brake method for a vane shaft

Abstract

The application discloses a kind of brake mechanism and braking method of vane shaft, it is related to vane shaft brake field, including the sleeve for being connected with vane shaft, and brake part, the end face of sleeve is provided with butt joint, brake part has butt joint slot, butt joint can be inserted into butt joint slot;Brake part has sliding cylinder, sliding cylinder can be close to sleeve or away from sleeve;Sliding cylinder has annular cavity and center hole, center hole is rotatably equipped with rotating shaft, butt joint slot is set on rotating shaft;Annular cavity is provided with friction cylinder, and the sliding friction between the cylinder wall of friction cylinder and the cavity wall of annular cavity can be generated;Friction cylinder and rotating shaft are provided with elastic belt between it.The vane shaft of the present application is not abruptly subjected to braking force when connected with brake mechanism, avoid the situation that the speed of vane shaft appears cliff-like drop, avoid vane shaft damage, and reduce the speed deviation between vane shaft and vane, so as to reduce the situation that the connection position of vane and vane shaft appears fracture occurs.

Description

Technical Field

[0001] This invention relates to the field of blade shaft braking, and in particular to a braking mechanism and method for a blade shaft. Background Technology

[0002] To ensure the long-term normal operation of wind turbines, it is necessary to shut them down for maintenance; or to shut them down before high wind speeds to prevent the blades from rotating at high speeds. High-speed blades, accompanied by large centrifugal forces, can easily damage the blades and the connection between the blades and the shaft. Therefore, in either of these situations, it is necessary to brake the blades or the blade shaft.

[0003] Currently, most small wind turbines do not have braking mechanisms to brake the blades or blade shafts. Large wind turbines, however, do have braking mechanisms, which currently fall into two categories. The first type involves a clutch between the braking mechanism and the blade shaft. When the blade shaft rotates normally, the clutch disengages, and the braking mechanism is not connected to the blade shaft. During braking, the clutch connects the braking mechanism to the blade shaft, and the braking mechanism brakes the blade shaft through friction or other means. The second type maintains a connection between the braking mechanism and the blade shaft. When the blade shaft rotates normally, the braking mechanism does not apply resistance to the blade shaft. During braking, the braking mechanism applies resistance to the blade shaft in the opposite direction to the blade torque, such as by applying reverse current or electrical short-circuit braking, to achieve braking of the blade shaft.

[0004] In the above-mentioned method, at the moment the braking mechanism brakes the blade shaft, the blade shaft is subjected to a large braking force, which will cause a large fluctuation in speed. This will not only cause the blade shaft to vibrate and be damaged, but also cause a speed deviation between the blade and the blade shaft due to the inertia of the blade, which will lead to breakage at the connection between the blade and the blade shaft.

[0005] In summary, when a braking mechanism brakes the blade shaft, there is a need in the art for a braking mechanism that can reduce damage to the blade shaft and blades. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned problems by providing a braking mechanism and method for a blade shaft, which prevents the blade shaft from being abruptly subjected to braking force when connected to the braking mechanism, avoids a sudden drop in the speed of the blade shaft, prevents damage to the blade shaft, and reduces the speed deviation between the blade shaft and the blade, thereby reducing the occurrence of breakage at the connection point between the blade and the blade shaft.

[0007] The technical solution adopted in this invention is as follows: A braking mechanism for a blade shaft includes a bushing for connecting to the blade shaft and a braking part. A butt joint is provided at the end face of the bushing, and the braking part has a mating groove. The butt joint can be inserted into the mating groove to connect the bushing and the braking part. The braking part has a sliding cylinder, which is slidably mounted on a wind turbine or tower. The sliding cylinder can be close to or away from the bushing. The sliding cylinder has a coaxial annular cavity and a central hole. A rotating shaft is rotatably mounted coaxially within the central hole, and the mating groove is provided on the end face of the rotating shaft. A friction cylinder is provided within the annular cavity, and the cylinder wall of the friction cylinder can generate sliding friction with the cavity wall of the annular cavity. The annular cavity surrounds the rotating shaft, and several elastic bands are provided between the friction cylinder and the rotating shaft. One end of each elastic band is fixedly connected to the rotating shaft, and the other end of each elastic band is fixedly connected to the friction cylinder.

[0008] Furthermore, an annular notch is provided between the annular cavity and the central hole, and all elastic bands are located within the annular notch.

[0009] Furthermore, the positions where the elastic band connects to the rotating shaft are evenly distributed along the circumference of the rotating shaft; the positions where the elastic band connects to the friction cylinder are evenly distributed along the circumference of the friction cylinder.

[0010] Furthermore, a bearing is provided between the rotating shaft and the central hole.

[0011] Furthermore, the braking unit also includes a mounting cylinder for mounting on a wind turbine or tower, wherein the sliding cylinder is assembled inside the mounting cylinder and the sliding cylinder and the mounting cylinder are connected in an axial sliding manner.

[0012] Furthermore, a sliding groove is provided inside the mounting cylinder, and a sliding body is provided on the outer wall of the sliding cylinder. The sliding body is slidably connected to the sliding groove, and the length direction of the sliding groove is parallel to the axial direction of the mounting cylinder.

[0013] Furthermore, a linear actuator is provided inside the mounting cylinder, and the linear actuator is connected to the end of the sliding cylinder.

[0014] Furthermore, the cross-sectional shape of the connector is non-circular, and the geometry of the mating groove matches the geometry of the mating groove.

[0015] Furthermore, the cross-section of the connector is star-shaped.

[0016] A method for braking a blade shaft, using the aforementioned braking mechanism, includes the following steps:

[0017] S1: The linear actuator pushes the sliding cylinder toward the bushing;

[0018] S2: Insert the connector into the mating groove to complete the mating of the bushing and the brake unit;

[0019] S3: The blade shaft rotates with the bushing, the bushing rotates with the rotating shaft, and the rotating shaft rotates relative to the sliding cylinder on the same axis.

[0020] S4: The rotation of the rotating shaft will cause the elastic band to gradually deform, and the elastic band will begin to have an elastic force F0 and gradually increase; the elastic force F0 of the elastic band acts on the rotating shaft and the friction cylinder in a non-radial direction.

[0021] S5: When the elastic force F0 of the elastic band is insufficient to overcome the static friction between the friction cylinder and the annular cavity, the elastic force F0 of the elastic band inhibits the rotation of the rotating shaft and initially decelerates the blade shaft.

[0022] S6: When the elastic force F0 of the elastic band is sufficient to overcome the static friction between the friction cylinder and the annular cavity, the friction cylinder rotates in the annular cavity under the action of the elastic force F0 of the elastic band, generating dynamic friction between itself and the inner wall of the annular cavity; the dynamic friction between the friction cylinder and the annular cavity consumes the elastic potential energy of the elastic band, and the blade shaft converts kinetic energy into the elastic potential energy of the elastic band through the rotating shaft, continuously consuming the kinetic energy from the blade shaft on the rotating shaft;

[0023] S7: Braking of the blade shaft is completed when the friction cylinder stops rotating and the kinetic energy provided by the blade shaft to the rotating shaft is insufficient to cause the elastic band to continue to deform.

[0024] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0025] 1. The present invention uses the buffer of the elastic band to prevent the blade shaft from being abruptly subjected to braking force when it begins to be braked, thus avoiding a sudden drop in the speed of the blade shaft, preventing damage to the blade shaft, and reducing the speed deviation between the blade shaft and the blade, thereby reducing the occurrence of breakage at the connection between the blade and the blade shaft.

[0026] 2. This invention consumes the kinetic energy from the blade shaft through friction between the friction cylinder and the annular cavity, effectively braking the blade shaft. Attached Figure Description

[0027] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0028] Figure 1 This is a schematic diagram of the braking mechanism disclosed in this invention;

[0029] Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure along the AA direction;

[0030] Figure 3 This is a schematic diagram of the force analysis of the friction cylinder disclosed in this invention;

[0031] Figure 4 This is a geometric shape diagram of the connector disclosed in this invention;

[0032] The markings in the diagram are: 1-shaft sleeve; 11-joint; 2-rotating shaft; 21-connecting groove; 3-bearing; 4-elastic band; 41-annular notch; 5-friction cylinder; 6-sliding cylinder; 61-slider; 7-mounting cylinder; 71-slide groove; 8-linear actuator. Detailed Implementation

[0033] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0034] Any feature disclosed in this specification, unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is merely one example of a series of equivalent or similar features.

[0035] Example 1

[0036] like Figure 1 - Figure 4 As shown, a braking mechanism for a blade shaft includes a bushing 1 for connecting to the blade shaft and a braking part. The braking part and the bushing 1 are separate. A mating joint 11 is provided at the end face of the bushing 1. The braking part has a mating groove 21, and the mating joint 11 can be inserted into the mating groove 21 to connect the bushing 1 and the braking part. The braking part has a sliding cylinder 6, which is slidably mounted on a wind turbine or tower. The sliding cylinder 6 can move closer to or away from the bushing 1. The sliding cylinder 6 has a coaxial annular cavity and a central hole. A rotating shaft 2 is rotatably mounted coaxially in the central hole. The mating groove 21 is provided on the end face of the rotating shaft 2. The sliding cylinder 6 moves the rotating shaft 2 closer to the bushing 1, realizing the mating groove 21 and the mating joint 11. The blade shaft can rotate relative to the sliding cylinder 6 with the rotating shaft 2. The sliding cylinder 6 moves the rotating shaft 2 away from the bushing 1, realizing the separation of the mating groove 21 and the mating joint 11, and the motion transmission between the blade shaft and the rotating shaft 2 is disconnected.

[0037] In this embodiment, a friction cylinder 5 is provided inside the annular cavity, and the cylinder wall of the friction cylinder 5 can generate sliding friction with the cavity wall of the annular cavity; the annular cavity surrounds the rotating shaft 2, and an elastic band 4 is provided between the friction cylinder 5 and the rotating shaft 2, one end of the elastic band 4 is fixedly connected to the rotating shaft 2, and the other end of the elastic band 4 is fixedly connected to the friction cylinder 5.

[0038] In this embodiment, when braking the blade shaft, the elastic band 4 provides buffering, so that the blade shaft is abruptly subjected to braking force when the braking effect begins, avoiding a sudden drop in the speed of the blade shaft, preventing damage to the blade shaft, and reducing the speed deviation between the blade shaft and the blade, thereby reducing the possibility of breakage at the connection between the blade and the blade shaft; the friction between the friction cylinder 5 and the annular cavity consumes the kinetic energy from the blade shaft, effectively achieving braking of the blade shaft.

[0039] Specifically, after the connector 11 is connected to the docking groove 21, the blade shaft rotates the rotating shaft 2 through the bushing 1. The rotation of the rotating shaft 2 causes the other end of the elastic band 4 to move, thereby causing the elastic band 4 to gradually deform and begin to have elastic potential energy. As the rotating shaft 2 rotates, the elastic force F0 of the elastic band 4 gradually increases. At this time, the elastic force F0 of the elastic band 4 will act on the rotating shaft 2 and the friction cylinder 5. The elastic force F0 acting on the rotating shaft 2 will inhibit the rotation of the rotating shaft 2, thereby initially decelerating the blade shaft. The braking force gradually increases from zero, effectively avoiding the blade shaft from being suddenly subjected to braking force when it begins to be braked, thus avoiding a precipitous drop in the speed of the blade shaft.

[0040] It should be noted that since the deformation of the elastic band 4 is caused by the rotation of one end following the rotation of the rotating shaft 2, the elastic force F0 of the elastic band 4 must act on the rotating shaft 2 and the friction cylinder 5 in a non-radial direction. Therefore, the elastic force F0 has two components: one is the radial component F1 of the rotating shaft 2 and the friction cylinder 5, F1 = F0 * cosα, where α is the angle between the tangent of the connection point of the elastic band 4 and the friction cylinder 5 to the tangent direction on the surface of the rotating shaft 2 and the radial direction; the other is the tangential component F2 of the rotating shaft 2 and the friction cylinder 5 in the circumferential direction, F2 = F0 * sinα. The radial component F1 provides pressure between the friction cylinder 5 and the annular cavity to increase the dynamic friction between the friction cylinder 5 and the annular cavity. The tangential component F2 inhibits the rotation of the rotating shaft 2 and provides power for the rotation of the friction cylinder 5 to overcome the dynamic friction between the friction cylinder 5 and the annular cavity.

[0041] It should be noted that, in order to avoid the real-time frictional force f1 between the friction cylinder 5 and the annular cavity always being greater than the tangential component F2, and to ensure that the friction cylinder 5 can be effectively tractioned to rotate as the elastic force F0 increases, it is necessary to ensure that f1 = f0 + μF1 < F2, where f0 is the frictional force between the friction cylinder 5 and the annular cavity when the friction cylinder 5 is not subjected to the elastic force; and μ is the coefficient of kinetic friction. Specifically, this can be achieved by selecting the roughness of the inner wall of the friction cylinder 5, the roughness of the inner wall of the annular cavity (actually selecting the coefficient of kinetic friction μ), and / or selecting the distance between the inner wall of the friction cylinder 5 and the outer wall of the rotating shaft 2 (actually selecting the angle α), and / or selecting the material of the elastic band 4 (actually selecting the elastic coefficient of the elastic band 4). The specific parameters are determined according to the actual working conditions and will not be elaborated further in this specification. Priority should be given to the design of the distance between the inner wall of the friction cylinder 5 and the outer wall of the rotating shaft 2, because this factor is the easiest to adjust during manufacturing and assembly.

[0042] In this embodiment, during the initial braking of the blade shaft, the tangential force F2 is insufficient to overcome the static friction between the friction cylinder 5 and the annular cavity. The elastic force F0 of the elastic band 4 inhibits the rotation of the rotating shaft 2, thus initially decelerating and braking the blade shaft. As the rotating shaft 2 continues to rotate, the elastic force F0 of the elastic band 4 gradually increases, and its degree of inhibition on the rotating shaft 2 gradually increases. Until f1 = f0 + μF1 < F2, that is, when the tangential force is sufficient to overcome the friction between the friction cylinder 5 and the annular cavity, sliding friction is generated between the friction cylinder 5 and the inner wall of the annular cavity, thereby consuming the elastic potential energy of the elastic band 4. The kinetic energy obtained by the rotating shaft 2 from the blade shaft provides elastic potential energy to the elastic band 4, thereby achieving deceleration and braking of the blade shaft through the sliding friction between the friction cylinder 5 and the inner wall of the annular cavity. Until the kinetic energy provided by the blade shaft to the rotating shaft 2 can no longer cause the elastic band 4 to continue to deform, and the friction cylinder 5 is in a stopped rotating state, the braking of the blade shaft is completed.

[0043] Example 2

[0044] Based on Example 1, further feasible implementation methods are proposed.

[0045] In one feasible implementation, an annular notch 41 is provided between the annular cavity and the central hole, and all elastic bands 4 are located within the annular notch 41. The rotation of the rotating shaft 2 causes the elastic bands 4 to deform and move, and the annular belt causes the friction cylinder 5 to rotate, both of which require the elastic bands 4 to deform and move in the circumferential direction. The design of the annular notch 41 provides space for the deformation and movement of the elastic bands 4.

[0046] In one feasible implementation, the positions where several elastic bands 4 are connected to the rotating shaft 2 are evenly distributed around the circumference of the rotating shaft 2; the positions where the elastic bands 4 are connected to the friction cylinder 5 are evenly distributed around the circumference of the friction cylinder 5, ensuring uniform force distribution and uniform force points.

[0047] In one feasible implementation, a bearing 3 is provided between the rotating shaft 2 and the central hole. The bearing 3 can improve the rotational stability of the rotating shaft 2 on the one hand, and reduce the friction between the outer wall of the rotating shaft 2 and the inner wall of the central hole on the other hand. This can minimize the braking effect of the friction on the blade shaft when the joint 11 and the docking groove 21 are docked, and effectively reduce the sudden drop in speed of the blade shaft at the start of braking.

[0048] In one feasible implementation, the braking part further includes a mounting cylinder 7, which is used to install on a wind turbine or tower. The sliding cylinder 6 is assembled inside the mounting cylinder 7 and is connected to the mounting cylinder 7 in an axial direction. The sliding cylinder 6 is slidably assembled on the wind turbine or tower through the mounting cylinder 7, avoiding the need to re-machine an assembly position for the sliding cylinder 6 to slide on the wind turbine or tower.

[0049] Specifically, the mounting cylinder 7 is provided with a sliding groove 71, and the outer wall of the sliding cylinder 6 is provided with a sliding body 61. The sliding body 61 is slidably connected to the sliding groove 71, and the length direction of the sliding groove 71 is parallel to the axial direction of the mounting cylinder 7. The sliding body 61 slides in the sliding groove 71, so that the sliding cylinder 6 slides in the mounting cylinder 7, thereby allowing the sliding cylinder 6 to move closer to or away from the bushing 1. On the other hand, the sliding groove 71 constrains the sliding body 61 to make circumferential movements, effectively constraining the sliding cylinder 6 to make circumferential movements, providing a basis for the friction cylinder 5 and the annular cavity to make relative circumferential sliding.

[0050] In one feasible implementation, a linear actuator 8 is provided inside the mounting cylinder 7. The linear actuator 8 is connected to the end of the sliding cylinder 6. The linear actuator 8 pushes the sliding cylinder 6 to slide relative to the mounting cylinder 7, so that the sliding cylinder 6 moves closer to or away from the bushing 1.

[0051] Furthermore, the linear actuator 8 is a hydraulic cylinder or a linear motor, the specific structure of which is known to those skilled in the art and will not be described in detail in this specification.

[0052] Example 3

[0053] Based on any one of the implementation methods in Examples 1-2, further feasible specific implementation methods are proposed.

[0054] In one feasible implementation, the cross-sectional shape of the connector 11 is non-circular, and the geometry of the mating groove 21 is matched with the geometry of the mating groove 21 to ensure that the torque of the blade shaft can be transmitted to the rotating shaft 2.

[0055] In one feasible implementation, the cross-section of the connector 11 is star-shaped, which increases the probability of the connector 11 being inserted into the docking groove 21, thereby achieving the purpose of rapid docking.

[0056] Example 4

[0057] A method for braking a blade shaft, using the aforementioned braking mechanism, includes the following steps when braking the blade shaft:

[0058] S1: Linear driver 8 pushes sliding cylinder 6 toward bushing 1.

[0059] S2: Insert the connector 11 into the mating groove 21 to complete the mating of the bushing 1 and the brake unit.

[0060] S3: The blade shaft rotates with the bushing 1, and the bushing 1 rotates with the rotating shaft 2. The rotating shaft 2 rotates relative to the sliding cylinder 6 on the same axis.

[0061] S4: As the rotating shaft 2 rotates, the elastic band 4 gradually deforms, and the elastic band 4 begins to have an elastic force F0, which gradually increases. The elastic force F0 of the elastic band 4 acts on the rotating shaft 2 and the friction cylinder 5 in a non-radial direction. Specifically, the elastic force F0 of the elastic band 4 has two directional components: one is the radial component F1 in the radial direction of the rotating shaft 2 and the friction cylinder 5, F1 = F0 * cosα; the other is the tangential component F2 in the circumferential direction of the rotating shaft 2 and the friction cylinder 5, F2 = F0 * sinα. The radial component F1 provides pressure between the friction cylinder 5 and the annular cavity to increase the dynamic friction between the friction cylinder 5 and the annular cavity. The tangential component F2 inhibits the rotation of the rotating shaft 2 and provides power for the rotation of the friction cylinder 5, overcoming the dynamic friction between the friction cylinder 5 and the annular cavity.

[0062] S5: When the elastic force F0 of the elastic band 4 is insufficient to overcome the static friction between the friction cylinder 5 and the annular cavity, that is, in the initial stage of braking the blade shaft, the tangential component force F2 is insufficient to overcome the friction between the friction cylinder 5 and the annular cavity, and f1=f0+μF1>F2; the elastic force F0 of the elastic band 4 inhibits the rotation of the rotating shaft 2 and initially decelerates the blade shaft.

[0063] S6: As the blade shaft is braked, the blade shaft continues to rotate with the rotating shaft 2. The rotation of the rotating shaft 2 causes the elastic force of the elastic band 4 to continuously increase. When the elastic force F0 of the elastic band 4 is sufficient to overcome the static friction between the friction cylinder 5 and the annular cavity, that is, when the tangential component F2 is sufficient to overcome the frictional force between the friction cylinder 5 and the annular cavity, and f1=f0+μF1<F2, under the action of the tangential component F2 of the friction cylinder 5, the friction cylinder 5 rotates in the annular cavity and generates dynamic friction with the inner wall of the annular cavity. The dynamic friction between the friction cylinder 5 and the annular cavity consumes the elastic potential energy of the elastic band 4, and the elastic band 4 recovers part of its deformation. The blade shaft converts kinetic energy into the elastic potential energy of the elastic band 4 through the rotating shaft 2, and the elastic band 4 increases its deformation. Thus, the blade shaft is indirectly braked by the dynamic friction between the friction cylinder 5 and the annular cavity. In this process, there are three situations as described in steps S61-S63; the specific steps are as follows: steps S61-S64.

[0064] S61: If the increased deformation of the elastic band 4 is greater than the restored deformation of the elastic band 4, that is, the linear velocity of the rotating shaft 2 is greater than the linear velocity of the friction cylinder 5, the deformation of the elastic band 4 will continue to increase, and the elastic force F0 of the elastic band 4 will increase. Since the direction of the elastic force F0 is not the tangential direction of the friction cylinder 5, the radial component force F1 between the friction cylinder 5 and the annular cavity will increase, that is, the radial pressure between the friction cylinder 5 and the annular cavity will increase, the friction force between the friction cylinder 5 and the annular cavity will increase, and the tangential component force F2 on the friction cylinder 5 will increase, the rotation speed of the friction cylinder 5 will increase, and more elastic potential energy of the elastic band 4 will be consumed to overcome friction and do work, thereby improving the braking efficiency of the blade shaft.

[0065] Furthermore, the elastic band 4 will stop deforming until the increased deformation equals the restored deformation, or until the deformation reaches its maximum value. The friction between the friction cylinder 5 and the annular cavity will then reach its maximum value, allowing the friction cylinder 5 to dissipate the kinetic energy from the blade shaft with maximum energy consumption. After the deformation reaches its maximum value, the elastic band 4 will transmit tension, meaning the friction cylinder 5 will experience both elastic force F0 and tension from the elastic band 4, causing its speed to increase rapidly. This achieves synchronous rotation between the friction cylinder 5 and the rotating shaft 2 through the traction of the elastic band 4. This state ends when the increased deformation of the elastic band 4 is less than its restored deformation.

[0066] S62: If the increased deformation of the elastic band 4 is equal to the restored deformation of the elastic band 4, that is, the linear velocity of the rotating shaft 2 is the same as the linear velocity of the friction cylinder 5, the elastic potential energy converted from the kinetic energy of the elastic band 4 from the blade shaft is just consumed by the friction between the friction cylinder 5 and the annular cavity; this state ends when the increased deformation of the elastic band 4 is less than the restored deformation of the elastic band 4.

[0067] S63: Since the deformation recovery of the elastic band 4 is delayed, which is a common characteristic of all elastic elements, and the speed change of the friction cylinder 5 is also delayed, during the entire process of braking the blade shaft, the linear velocity of the friction cylinder 5 is greater than the linear velocity of the rotating shaft 2, that is, the increase in deformation of the elastic band 4 is less than the recovery of deformation of the elastic band 4. If this state occurs, the deformation of the elastic band 4 gradually recovers, and the elastic force F0 of the elastic band 4 gradually decreases until the elastic force F0 of the elastic band 4 is insufficient to overcome the static friction between the friction cylinder 5 and the annular cavity, at which point the speed of the friction cylinder 5 decreases; until step S62 or step S63 occurs or the friction cylinder 5 stops rotating.

[0068] S64: If the blade shaft is still rotating, repeat steps S61-S63 to consume the rotational kinetic energy of the blade shaft.

[0069] S7: Braking of the blade shaft is completed when the friction cylinder 5 stops rotating and the kinetic energy provided by the blade shaft to the rotating shaft 2 is insufficient to cause the elastic band 4 to continue to deform.

[0070] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A braking mechanism for a blade shaft, comprising a bushing (1) for connection with the blade shaft, and a braking part; characterized in that: The bushing (1) has a butt joint (11) at its end face, and the braking part has a mating groove (21). The butt joint (11) can be inserted into the mating groove (21) to connect the bushing (1) and the braking part. The braking part has a sliding cylinder (6), which is slidably mounted on the wind turbine or tower. The sliding cylinder (6) can be close to or away from the bushing (1). The sliding cylinder (6) has a coaxial annular cavity and a central hole, and the central hole is coaxial. The linear rotating assembly is equipped with a rotating shaft (2), and a mating groove (21) is provided on the end face of the rotating shaft (2); a friction cylinder (5) is provided inside the annular cavity, and the cylinder wall of the friction cylinder (5) can generate sliding friction with the cavity wall of the annular cavity; the annular cavity surrounds the rotating shaft (2), and several elastic bands (4) are provided between the friction cylinder (5) and the rotating shaft (2), one end of the elastic band (4) is fixedly connected to the rotating shaft (2), and the other end of the elastic band (4) is fixedly connected to the friction cylinder (5).

2. The braking mechanism according to claim 1, characterized in that: An annular notch (41) is provided between the annular cavity and the central hole, and all elastic bands (4) are located within the annular notch (41).

3. The braking mechanism according to claim 1, characterized in that: The positions where several elastic bands (4) are connected to the rotating shaft (2) are evenly distributed around the circumference of the rotating shaft (2); the positions where the elastic bands (4) are connected to the friction cylinder (5) are evenly distributed around the circumference of the friction cylinder (5).

4. The braking mechanism according to claim 1, characterized in that: A bearing (3) is provided between the rotating shaft (2) and the central hole.

5. The braking mechanism according to claim 1, characterized in that: The braking part also includes a mounting cylinder (7), which is used to install on a wind turbine or tower. The sliding cylinder (6) is assembled inside the mounting cylinder (7) and is connected to the mounting cylinder (7) in a sliding manner along the axial direction.

6. The braking mechanism according to claim 5, characterized in that: The mounting cylinder (7) is provided with a sliding groove (71), and the outer wall of the sliding cylinder (6) is provided with a sliding body (61). The sliding body (61) is slidably connected to the sliding groove (71), and the length direction of the sliding groove (71) is parallel to the axial direction of the mounting cylinder (7).

7. The braking mechanism according to claim 5, characterized in that: A linear actuator (8) is provided inside the mounting cylinder (7), and the linear actuator (8) is connected to the end of the sliding cylinder (6).

8. The braking mechanism according to any one of claims 1-7, characterized in that: The cross-sectional shape of the connector (11) is non-circular, and the geometry of the mating groove (21) matches the geometry of the mating groove (21).

9. The braking mechanism according to claim 8, characterized in that: The cross-section of the connector (11) is star-shaped.

10. A method for braking a blade shaft, using the braking mechanism for the blade shaft according to any one of claims 1-9, characterized in that: Includes the following steps: S1: The linear actuator (8) pushes the sliding cylinder (6) toward the bushing (1); S2: Insert the connector (11) into the mating groove (21) to complete the mating of the bushing (1) with the brake part; S3: The blade shaft rotates with the bushing (1), the bushing (1) rotates with the rotating shaft (2), and the rotating shaft (2) rotates relative to the sliding cylinder (6) on the same axis; S4: The rotation of the rotating shaft (2) will cause the elastic band (4) to gradually deform. The elastic band (4) will start to have an elastic force F0 and gradually increase. The elastic force F0 of the elastic band (4) acts on the rotating shaft (2) and the friction cylinder (5) in a non-radial direction. S5: When the elastic force F0 of the elastic band (4) is insufficient to overcome the static friction between the friction cylinder (5) and the annular cavity, the elastic force F0 of the elastic band (4) inhibits the rotation of the rotating shaft (2) and initially decelerates the blade shaft. S6: When the elastic force F0 of the elastic band (4) is sufficient to overcome the static friction between the friction cylinder (5) and the annular cavity, the friction cylinder (5) rotates in the annular cavity under the action of the elastic force F0 of the elastic band (4), and dynamic friction is generated between it and the inner wall of the annular cavity; the dynamic friction between the friction cylinder (5) and the annular cavity consumes the elastic potential energy of the elastic band (4), and the blade shaft converts the kinetic energy into the elastic potential energy of the elastic band (4) through the rotating shaft (2), continuously consuming the kinetic energy from the blade shaft on the rotating shaft (2); S7: The braking of the blade shaft is completed when the kinetic energy provided by the blade shaft to the rotating shaft (2) is no longer sufficient to cause the elastic band (4) to continue to deform, and the friction cylinder (5) is in a stopped rotating state.

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