Lead screw and lead screw braking method

Abstract

The present invention relates to the field of screws, and more specifically, to a screw and a screw braking method. The screw includes a screw unit, a nut unit, a brake block, and a ball; the screw includes a first working state and a second working state; the first working state includes: the position of the nut body moves relative to the position of the screw body, driving the brake block to move in the first brake groove; the second working state includes: the position of the nut body is fixed relative to the position of the screw body, the brake block is located in the first brake groove, and abuts against the end of the first brake groove. This solves the problem that when the ball moves at high speed, the impact force abutting against the screw is large, which is easy to damage the ball.

Description

Technical Field

[0001] The present invention relates to the field of lead screws, and in particular to a lead screw and a lead screw braking method. Background Art

[0002] A lead screw is a mechanical component that converts rotational motion into linear motion or vice versa. Common lead screw products include sliding screws, ball screws, and planetary roller screws. Among them, ball screws are suitable for precision transmission because they generate point contact rolling friction, have low friction, high transmission efficiency, and high precision, and are widely used in mechanical manufacturing.

[0003] Most existing ball screws achieve relative stillness of the nut and the screw by moving the ball to the end of the screw and braking by abutting the ball against the end of the screw. Ball braking can be applied to situations where the nut moves slowly. When the nut moves at high speed, the potential energy of the nut and the ball is large. When the ball abuts against the end of the screw, the impact force is large. Under long-term impact, the ball is easily damaged, reducing the service life of the screw. Summary of the invention

[0004] In order to solve the problem that when the ball moves at high speed, the impact force on the ball against the lead screw is large, which easily damages the ball, the present invention provides a lead screw and a lead screw braking method.

[0005] In a first aspect, this embodiment provides a lead screw, comprising:

[0006] A screw unit, the screw unit comprising a screw body, a first sliding groove and a first braking groove; the first sliding groove and the first braking groove are both arranged on the screw body, the first sliding groove is threaded, the first braking groove is threaded, the rotation direction of the first sliding groove is consistent with the rotation direction of the first braking groove, the pitch of the first sliding groove is equal to the pitch of the first braking groove, and the spiral length of the first braking groove is less than the spiral length of the first sliding groove;

[0007] A nut unit, the nut unit comprising a nut body and a second sliding groove, the second sliding groove being arranged on the inner circumferential surface of the nut body, the second sliding groove being in a threaded shape, and the second sliding groove being arranged in cooperation with the first sliding groove;

[0008] A brake block, one side of which is fixedly connected to the inner circumference of the nut body; when the nut body is sleeved on the screw rod body, the other side of the brake block is movably disposed in the first brake groove;

[0009] A ball, the ball being disposed in a cavity formed by the first sliding groove and the second sliding groove; a portion of the spherical surface of the ball abuts against the first sliding groove, and another portion of the spherical surface of the ball abuts against the second sliding groove;

[0010] The lead screw includes a first working state and a second working state; the first working state includes: the position of the nut body moves relative to the position of the lead screw body, driving the brake block to move in the first brake groove;

[0011] The second working state includes: the position of the nut body is fixed relative to the position of the screw rod body, and the brake block is located in the first brake groove and abuts against the end of the first brake groove.

[0012] In some embodiments, the lead screw also includes a second brake groove; the second brake groove is threaded, the second brake groove is arranged on the lead screw body, the second brake groove is connected to one end of the first brake groove, and the rotation direction of the second brake is consistent with that of the first brake; the pitch of the second brake groove is greater than or less than the pitch of the first brake groove; when the lead screw is in the second working state, the brake block abuts against the second brake groove.

[0013] In some embodiments, when the pitch of the second braking groove is smaller than the pitch of the first braking groove, the pitch of the second braking groove decreases uniformly from one end communicating with the first braking groove to the other end of the second braking groove.

[0014] In some embodiments, when the pitch of the second braking groove is greater than the pitch of the first braking groove, the pitch of the second braking groove increases uniformly from one end communicating with the first braking groove to the other end of the second braking groove.

[0015] In some embodiments, a groove depth of the second braking groove decreases uniformly from one end communicating with the first braking groove to the other end of the second braking groove.

[0016] In some embodiments, the brake block includes a connecting portion and a braking portion, one side of the connecting portion is fixedly connected to one side of the braking portion, and the other side of the connecting portion is fixedly connected to the inner circumferential surface of the nut body; when the screw body is in a first state, the braking portion is located in the first braking groove and moves; when the screw is in a second state, the braking portion abuts against the end of the first braking groove.

[0017] In some embodiments, the braking portion is integrally formed and fixedly connected to the connecting portion.

[0018] In some embodiments, the braking portion is spaced apart and fixedly connected to the connecting portion.

[0019] In some embodiments, the length of the first braking groove is L1, the length of the second braking groove is L2, and the ratio of L2 to L1 is 0.2-0.4.

[0020] In a second aspect, this embodiment provides a method for braking a lead screw, which is applied to the lead screw described in the first aspect and includes the following steps:

[0021] S11: Based on the fact that the ball is arranged in the chamber formed by the first sliding groove and the second sliding groove; a part of the spherical surface of the ball abuts against the first sliding groove, and another part of the spherical surface of the ball abuts against the second sliding groove, the nut body is moved toward the closed end of the first sliding groove;

[0022] S12: based on the movement of the nut body toward the closed end of the first sliding groove, the nut body drives the brake block to move in the first brake groove;

[0023] S13: Based on the brake block moving in the first brake groove, the brake block moves to the end of the first brake groove and abuts against the end of the first brake groove, and the position of the nut body is fixed relative to the position of the screw rod body.

[0024] In order to solve the problem that when the ball moves at high speed, the impact force against the screw rod is large, which easily damages the ball, the present invention has the following advantages:

[0025] By arranging a first braking groove on the screw unit, and the length of the first braking groove is smaller than the length of the first sliding groove, it is possible to achieve that when the brake block abuts against the end of the first braking groove, the position of the nut body is fixed relative to the position of the screw body, thereby avoiding contact between the ball and the end of the screw unit, and achieving the braking effect of the nut body, thereby solving the problem that when the ball moves at high speed and abuts against the screw, the impact force is large, the ball is easily damaged, and the service life of the screw is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of a lead screw;

[0027] Figure 2 It is the overall structural schematic diagram of the screw rod unit;

[0028] Figure 3 for Figure 2 A local enlarged schematic diagram of the middle A;

[0029] Figure 4 for Figure 2 A partial enlarged schematic diagram of point C in the middle;

[0030] Figure 5 It is a structural schematic diagram of the wire mother unit;

[0031] Figure 6 for Figure 5 A partial enlarged schematic diagram of point B in the middle;

[0032] Figure 7 It is a structural schematic diagram of the wire mother unit;

[0033] Figure 8 for Figure 7 A partial enlarged schematic diagram of point D in the middle;

[0034] Fig. 9 is a schematic diagram of the structure of the brake pad;

[0035] Fig.10 for Fig. 9 A partial enlarged schematic diagram of point E in the middle.

[0036] In the figure: 10, screw unit; 11, screw body; 12, first sliding groove; 13, first braking groove; 14, second braking groove; 141, first braking end; 142, second braking end; 143, third braking end; 20, nut unit; 21, nut body; 22, second sliding groove; 30, brake block; 31, connecting part; 32, braking part; 321, fourth braking end; 322, fifth braking end 323, sixth braking end. DETAILED DESCRIPTION

[0037] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, rather than implying any limitation on the scope of the present disclosure.

[0038] As used herein, the term "including" and its variants are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "based at least in part on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal" and the like is based on the orientation or position relationship shown in the accompanying drawings. These terms are mainly for better describing the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation. In addition, in addition to being used to indicate an orientation or position relationship, some of the above terms may also be used to indicate other meanings, such as the term "upper" may also be used to indicate a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to the specific circumstances. In addition, the terms "install", "set", "provided with", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be an internal connection between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0039] This embodiment discloses a screw, such as Figure 1 , Figure 2 , Figure 3 , Figure 5 As shown, including:

[0040] A screw unit 10, the screw unit 10 comprises a screw body 11, a first sliding groove 12 and a first braking groove 13; the first sliding groove 12 and the first braking groove 13 are both arranged on the screw body 11, the first sliding groove 12 is threaded, the first braking groove 13 is threaded, the rotation direction of the first sliding groove 12 is consistent with the rotation direction of the first braking groove 13, the pitch of the first sliding groove 12 is equal to the pitch of the first braking groove 13, and the spiral length of the first braking groove 13 is less than the spiral length of the first sliding groove 12;

[0041] The nut unit 20 includes a nut body 21 and a second sliding groove 22, wherein the second sliding groove 22 is disposed on the inner circumference of the nut body 21, the second sliding groove 22 is threaded, and the second sliding groove 22 is matched with the first sliding groove 12;

[0042] A brake block 30, one side of which is fixedly connected to the inner circumference of the nut body 21; when the nut body 21 is sleeved on the screw rod body 11, the other side of the brake block 30 is movably disposed in the first brake groove 13;

[0043] A ball (not shown in the figure), the ball is arranged in a cavity formed by the first sliding groove 12 and the second sliding groove 22; a part of the spherical surface of the ball abuts against the first sliding groove 12, and another part of the spherical surface of the ball abuts against the second sliding groove 22;

[0044] The lead screw includes a first working state and a second working state; the first working state includes: the position of the nut body 21 moves relative to the position of the lead screw body 11, driving the brake block 30 to move in the first brake groove 13;

[0045] The second working state includes: the position of the nut body 21 is fixed relative to the position of the screw rod body 11 , and the brake block 30 is located in the first brake groove 13 and abuts against the end of the first brake groove 13 .

[0046] In this embodiment, by setting the first brake groove 13 on the screw unit 10, and the length of the first brake groove 13 is less than the length of the first sliding groove 12, it is possible to achieve that when the brake block 30 abuts against the end of the first brake groove 13, the position of the nut body 21 is fixed relative to the position of the screw body 11, avoiding the contact between the ball and the end of the screw unit 10, and achieving the braking effect of the nut body 21, thereby solving the problem that when the ball moves at high speed, the impact force of the abutment with the screw is large, the ball is easily damaged, and the service life of the screw is reduced. In this embodiment, by setting the pitch of the first brake groove 13 to be equal to the pitch of the first sliding groove 12, it is possible to achieve that the part of the brake block 30 located in the first brake groove 13 can rotate and move synchronously with the screw nut unit 20, and when the brake block 30 does not abut against the first brake groove 13, the brake block 30 does not affect the movement of the screw nut unit 20.

[0047] In some embodiments, Figure 1 , Figure 2As shown, the lead screw also includes a second brake groove 14; the second brake groove 14 is threaded, the second brake groove 14 is arranged on the lead screw body 11, the second brake groove 14 is connected to one end of the first brake groove 13, and the rotation direction of the second brake is consistent with that of the first brake; the pitch of the second brake groove 14 is greater than or less than the pitch of the first brake groove 13; when the lead screw is in the second working state, the brake block 30 abuts against the second brake groove 14.

[0048] In this embodiment, by providing the second brake groove 14, and the second brake groove 14 is connected with the first brake groove 13, the connection point between the first brake groove 13 and the second brake groove 14 can also be set to a smooth transition, the second brake is consistent with the first brake in rotation, and the first brake groove 13 and the second brake groove 14 can be understood as two parts with different pitches on the same brake groove. The pitch of the second brake groove 14 is greater than or less than the pitch of the first brake groove 13, and the pitch of the second brake groove 14 is set to be unequal to the pitch of the first brake groove 13, so that when the brake block 30 moves from the first brake groove 13 to the second brake groove 14, it can abut against the second brake groove 14, thereby achieving braking of the nut unit 20, and avoiding the length of the first brake groove 13 being too short, so that the distance of movement of the nut unit 20 is too short. In this embodiment, the sum of the length of the first brake groove 13 and the length of the second brake groove 14 can be equal to the length of the first sliding groove 12, so as to increase the stroke of the nut unit 30 as much as possible while ensuring that the second brake groove 14 brakes the brake block 30. It can also solve the problem that when the ball moves at high speed, the impact force on the lead screw is large, the ball is easily damaged, and the service life of the lead screw is reduced.

[0049] In some embodiments, when the pitch of the second braking groove 14 is smaller than the pitch of the first braking groove 13 , the pitch of the second braking groove 14 decreases uniformly from one end communicating with the first braking groove 13 to the other end of the second braking groove 14 .

[0050] In this embodiment, the pitch of the second brake groove 14 is uniformly reduced from one end connected to the first brake groove 13 to the other end of the second brake groove 14, so that the pitch of the second brake groove 14 changes uniformly, so that when the brake block 30 moves in the second brake groove 14, the resistance change it receives will not be excessively drastic, which is conducive to preventing the brake block 30 from experiencing a sharp change in resistance due to the uneven pitch change of the second brake groove 14 during braking, causing excessive local stress and deformation of the brake block 30. In addition, by setting the pitch of the second brake groove 14 to a uniformly changing structure, the stress change on the screw body 11 will not be excessively drastic, and it can also prevent the screw body 11 from experiencing excessive stress changes due to the uneven pitch change of the second brake groove 14, thereby reducing the service life of the screw body.

[0051] In some embodiments, when the pitch of the second braking groove 14 is greater than the pitch of the first braking groove 13 , the pitch of the second braking groove 14 increases uniformly from one end communicating with the first braking groove 13 to the other end of the second braking groove 14 .

[0052] In this embodiment, the pitch of the second brake groove 14 is uniformly increased from one end connected to the first brake groove 13 to the other end of the second brake groove 14, so that the pitch of the second brake groove 14 changes uniformly, so that the resistance change of the brake block 30 when moving in the second brake groove 14 will not be excessively drastic, which is conducive to preventing the brake block 30 from experiencing a sharp change in resistance due to the uneven pitch change of the second brake groove 14 during braking, causing excessive local stress and deformation of the brake block 30. In addition, by setting the pitch of the second brake groove 14 to a uniformly changing structure, the stress change of the screw rod body 11 will not be excessively drastic, and it can also prevent the screw rod body 11 from experiencing excessive stress changes due to the uneven pitch change of the second brake groove 14, thereby reducing the service life of the screw rod body.

[0053] In some embodiments, the groove depth of the second braking groove 14 decreases uniformly from one end communicating with the first braking groove 13 to the other end of the second braking groove 14 .

[0054] In this embodiment, the groove depth of the second brake groove 14 is arranged to decrease uniformly from one end connected to the first brake groove 13 to the other end of the second brake groove 14, so that the second brake groove 14 can apply a uniformly increasing resistance to the brake block 30 when braking the brake block 30, thereby achieving an effect of uniform deceleration of the brake block 30, avoiding the groove depth of the second brake groove 14 from changing irregularly, resulting in a sharp change in the resistance applied to the brake block 30 and causing excessive changes in the local stress of the brake block 30, thereby preventing the brake block 30 from being reduced in service life.

[0055] In some embodiments, Figure 5 , Figure 6 As shown, the brake block 30 includes a connecting portion 31 and a braking portion 32, one side of the connecting portion 31 is fixedly connected to one side of the braking portion 32, and the other side of the connecting portion 31 is fixedly connected to the inner circumferential surface of the nut body 21; when the screw body is in the first state, the braking portion 32 is located in the first braking groove 13 and moves; when the screw is in the second state, the braking portion 32 abuts against the end of the first braking groove 13.

[0056] In this embodiment, the brake block 30 includes a connecting portion 31 and a braking portion 32, one side of the connecting portion 31 is fixedly connected to one side of the braking portion 32, and the other side of the connecting portion 31 is fixedly connected to the inner circumferential surface of the nut body 21; when the screw body is in the first state, the braking portion 32 is located in the first braking groove 13 and moves; when the screw is in the second state, the braking portion 32 abuts against the end of the first braking groove 13, thereby achieving braking of the brake block 30 and achieving the braking effect of the nut body 21, thereby solving the problem that when the ball moves at high speed, the impact force when abutting against the screw is large, the ball is easily damaged, and the service life of the screw is reduced.

[0057] In some embodiments, Figures 5 to 8 As shown, the braking portion 32 is integrally formed and fixedly connected to the connecting portion 31 .

[0058] In this embodiment, by setting the brake part 32 as an integrally formed structure and fixing the brake part 32 to the connecting part 31, the pressure resistance of the brake part 32 can be enhanced. When the brake part 32 abuts against the end of the first brake groove 13 or the second brake groove 14, the brake part 32 can be prevented from being damaged by collision when the nut unit 20 moves at a high speed. Figures 5 to 8 As shown, the braking portion 32 includes a fourth braking end 321, a fifth braking end 322, and a sixth braking end 323. Figure 2 , Figure 4 As shown, the second brake groove 14 includes a first brake end 141, a second brake end 142, and a third brake end 143. In this embodiment, when the pitch of the second brake groove 14 is smaller than the pitch of the first brake groove 13, the second brake end 142 abuts against the fourth brake end 321, when the pitch of the second brake groove 14 is larger than the pitch of the first brake groove 13, the third brake end 143 abuts against the sixth brake end 323, and when the groove depth of the second brake groove 14 decreases uniformly from one end connected to the first brake groove 13 to the other end of the second brake groove 14, the first brake end 141 abuts against the fifth brake end 322. In this embodiment, the brake block 32 can be set as a block-shaped protrusion with the same rotation direction and pitch as the first brake groove 13, so that the strip-shaped protrusion can rotate and move in the first brake groove 13, and when the protrusion abuts against the second brake groove 14, the contact surface between the brake portion 32 and the second brake groove 13 can be larger, thereby bringing a better braking effect.

[0059] In some embodiments, Fig. 9 , Fig.10 As shown, the braking portion 32 is fixedly connected to the connecting portion 31 at an interval.

[0060] In this embodiment, the braking portions 32 are fixedly connected to the connecting portion 31 at intervals, when the pitch of the second braking groove 14 is less than or greater than the pitch of the first braking groove 13, when the second braking end 142 abuts against the fourth braking end 321 or the third braking end 143 abuts against the sixth braking end 323, the adjacent braking portions 32 can apply friction force to the second braking groove 14 individually according to the pitch variation of the second braking groove 14, thereby enabling the brake block 30 to brake the second braking groove 14 with uniform or uneven pitch variation, and can achieve better braking effect, thereby improving the adaptability of the brake block 30.

[0061] Moreover, in the present embodiment, by setting the brake parts 32 to be fixedly connected with the connecting part 31 at intervals, when some brake parts 32 of the brake block 30 are worn out for a long time and the braking effect is reduced, the brake parts 32 with excessive wear can be cut off, and the brake parts 32 with no wear or less wear can be used for braking, thereby ensuring the braking effect. In the present embodiment, by setting the brake parts 32 to be fixedly connected with the connecting part 31 at intervals, the brake block 30 can be lightened, and the influence of the brake parts 30 on the movement of the nut body 21 when the lead screw is in the first state can be reduced, and the nut body 21 can be prevented from being subjected to a large vertical downward pulling force due to the excessive weight of the brake parts 30, and the centripetal force of the nut body 21 is increased when the nut body 21 rotates, which causes the ball to be squeezed excessively and the service life of the ball to be reduced. Moreover, by setting the brake parts 32 to be fixedly connected with the connecting part 31 at intervals, the wind resistance of the nut body 20 when it moves can be reduced, thereby saving the energy loss when the nut body moves. In this embodiment, the braking part 32 is fixedly connected to the connecting part 31 at intervals, and the connecting part is fixedly connected to the inner circumference of the nut body 21, which can not only ensure that the braking part 32 brings the above-described effect, but also ensure the stability when the connecting part 31 is connected to the braking part 32. In this embodiment, each braking part 32 can also be integrally formed with the connecting part 31.

[0062] In some embodiments, the length of the first braking groove 13 is L1, the length of the second braking groove 14 is L2, and the ratio of L2 to L1 is 0.2-0.4.

[0063] In this embodiment, by setting the ratio of the length of the second braking groove 14 to the length of the first braking groove 13 to 0.2-0.4, the length of the second braking groove 14 is smaller than that of the first braking groove 13, thereby ensuring that the moving distance of the nut body 21 is long enough and the nut body 21 can be effectively braked.

[0064] In this embodiment, preferably, the ratio of L2 to L1 is 0.3.

[0065] This embodiment discloses a screw braking method, comprising the following steps:

[0066] S11: Based on the fact that the ball is arranged in the chamber formed by the first sliding groove 12 and the second sliding groove 22; a part of the spherical surface of the ball abuts against the first sliding groove 12, and another part of the spherical surface of the ball abuts against the second sliding groove 22, the nut body 21 is moved toward the closed end of the first sliding groove 12;

[0067] S12: As the nut body 21 moves toward the closed end of the first sliding groove 12 , the nut body 21 drives the brake block 30 to move in the first brake groove 13 ;

[0068] S13: Based on the brake block 30 moving in the first brake groove 13, the brake block 30 moves to the end of the first brake groove 13 and abuts against the end of the first brake groove 13, and the position of the nut body 21 is fixed relative to the position of the screw rod body 11.

[0069] In this embodiment, by setting the first brake groove 13 on the screw unit 10, and the length of the first brake groove 13 is less than the length of the first sliding groove 12, it is possible to achieve that when the brake block 30 abuts against the end of the first brake groove 13, the position of the nut body 21 is fixed relative to the position of the screw body 11, avoiding the contact between the ball and the end of the screw unit 10, and achieving the braking effect of the nut body 21, thereby solving the problem that when the ball moves at high speed, the impact force of the abutment with the screw is large, the ball is easily damaged, and the service life of the screw is reduced. In this embodiment, by setting the pitch of the first brake groove 13 to be equal to the pitch of the first sliding groove 12, it is possible to achieve that the part of the brake block 30 located in the first brake groove 13 can rotate and move synchronously with the screw nut unit 20, and when the brake block 30 does not abut against the first brake groove 13, the brake block 30 does not affect the movement of the screw nut unit 20.

[0070] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present disclosure, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present disclosure.

Claims

1. A lead screw, characterized in that: include: A screw unit, the screw unit comprising a screw body, a first sliding groove and a first braking groove; the first sliding groove and the first braking groove are both arranged on the screw body, the first sliding groove is threaded, the first braking groove is threaded, the rotation direction of the first sliding groove is consistent with the rotation direction of the first braking groove, the pitch of the first sliding groove is equal to the pitch of the first braking groove, and the spiral length of the first braking groove is less than the spiral length of the first sliding groove; A nut unit, the nut unit comprising a nut body and a second sliding groove, the second sliding groove being arranged on the inner circumferential surface of the nut body, the second sliding groove being in a threaded shape, and the second sliding groove being arranged in cooperation with the first sliding groove; A brake block, one side of which is fixedly connected to the inner circumference of the nut body; when the nut body is sleeved on the screw rod body, the other side of the brake block is movably disposed in the first brake groove; A ball, the ball being disposed in a cavity formed by the first sliding groove and the second sliding groove; a portion of the spherical surface of the ball abuts against the first sliding groove, and another portion of the spherical surface of the ball abuts against the second sliding groove; The lead screw includes a first working state and a second working state; the first working state includes: the position of the nut body moves relative to the position of the lead screw body, driving the brake block to move in the first brake groove; The second working state includes: the position of the nut body is fixed relative to the position of the screw rod body, and the brake block is located in the first brake groove and abuts against the end of the first brake groove.

2. A lead screw according to claim 1, characterized in that: The lead screw also includes a second brake groove; the second brake groove is threaded, the second brake groove is arranged on the lead screw body, the second brake groove is connected to one end of the first brake groove, and the rotation direction of the second brake is consistent with that of the first brake; the pitch of the second brake groove is greater than or less than the pitch of the first brake groove; when the lead screw is in the second working state, the brake block abuts against the second brake groove.

3. A lead screw according to claim 2, characterized in that: When the pitch of the second braking groove is smaller than the pitch of the first braking groove, the pitch of the second braking groove decreases uniformly from one end communicating with the first braking groove to the other end of the second braking groove.

4. A lead screw according to claim 2, characterized in that: When the pitch of the second braking groove is greater than the pitch of the first braking groove, the pitch of the second braking groove increases uniformly from one end communicating with the first braking groove to the other end of the second braking groove.

5. A lead screw according to claim 2, characterized in that: The groove depth of the second braking groove decreases uniformly from one end communicating with the first braking groove to the other end of the second braking groove.

6. A lead screw according to claim 1, characterized in that: The brake block includes a connecting portion and a braking portion, one side of the connecting portion is fixedly connected to one side of the braking portion, and the other side of the connecting portion is fixedly connected to the inner circumferential surface of the nut body; when the screw body is in a first state, the braking portion is located in the first braking groove and moves; when the screw is in a second state, the braking portion abuts against the end of the first braking groove.

7. A lead screw according to any one of claim 6, characterized in that: The braking portion is integrally formed and fixedly connected to the connecting portion.

8. A lead screw according to any one of claim 6, characterized in that: The braking part is arranged at an interval and fixedly connected to the connecting part.

9. A lead screw according to claim 2, characterized in that: The length of the first braking groove is L1, the length of the second braking groove is L2, and the ratio of L2 to L1 is 0.2-0.

4.

10. A screw braking method, wherein the screw braking method is applied to the screw according to any one of claims 1 to 9, characterized in that: The following steps are involved: S11: Based on the fact that the ball is arranged in the chamber formed by the first sliding groove and the second sliding groove; a part of the spherical surface of the ball abuts against the first sliding groove, and another part of the spherical surface of the ball abuts against the second sliding groove, the nut body is moved toward the closed end of the first sliding groove; S12: based on the movement of the nut body toward the closed end of the first sliding groove, the nut body drives the brake block to move in the first brake groove; S13: Based on the brake block moving in the first brake groove, the brake block moves to the end of the first brake groove and abuts against the end of the first brake groove, and the position of the nut body is fixed relative to the position of the screw rod body.

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