Double-nut ball screw pair with bidirectional load and its operation control method and preload adjustment method, nut ball screw pair with unidirectional load

Abstract

The present invention discloses a bidirectionally loaded double-nut ball screw pair and an operation control method and a preload adjustment method thereof, a unidirectionally loaded nut ball screw pair, and a bidirectionally loaded double-nut ball screw pair, comprising: a screw, a nut, a preload mechanism, a preload mechanism, a nut, and a nut seat; the nut and the nut are sleeved and mounted on the screw, the nut seat supports the outer sides of the nut and the nut, and the nut seat limits the nut and the nut in the axial direction; the two ends of the nut seat are respectively mounted with a locking mechanism and a locking mechanism; the locking mechanism is used to control the degree of freedom of the rotation direction of the nut; the locking mechanism is used to control the degree of freedom of the rotation direction of the nut; the preload mechanism is used to support the nut in the preload rotation direction; the preload mechanism is used to support the nut in the preload rotation direction. The present invention can effectively improve the smoothness of the operation of the screw pair.

Description

Technical Field

[0001] The present invention belongs to the technical field of transmission devices, and in particular relates to a bidirectionally loaded double-nut ball screw pair and an operation control method and a preload adjustment method thereof, and a unidirectionally loaded nut ball screw pair. Background Art

[0002] Due to errors in the machining accuracy and assembly errors of the ball screw and nut, it is often necessary to apply a pre-tightening force to the nut to eliminate axial clearance, increase system rigidity, and improve positioning accuracy.

[0003] At present, a double-nut structure is used to achieve preload adjustment, which mainly includes gasket type, positioning pin type, differential tooth type, spring type, etc. The first three types mainly generate preload by causing one set of raceways and steel balls to undergo axial relative displacement relative to another set of raceways and steel balls to ensure transmission accuracy.

[0004] However, all three types are rigid connections, that is, after the screw pair leaves the factory, the relative displacement between the two sets of raceways of the double nut has been adjusted. When the middle diameter of the screw raceway increases and the lead accuracy changes, the preload force will fluctuate. An increase in the preload force will reduce the life of the screw pair, while a decrease will reduce the transmission accuracy. Secondly, this fluctuation in the preload force will also affect the smoothness of the screw pair's operation.

[0005] The spring type adds an elastic preload between the double nuts through elastic connection. Although the elastic preload can offset part of the changes in the mean diameter and lead of the screw raceway, this type of structure can only bear load in one direction at present. Because the load-bearing direction of the double nut group in the double nut structure is different, the load-bearing nuts in the double nut group are also different. That is, when the double nut group is loaded in a certain direction, one nut bears the load and the other nut mainly provides preload. When the load direction changes, the load-bearing force will be transferred to the spring preload, causing the nut ball on one side to fail. The nut that previously provided preload will also become a load-bearing nut. Because of this characteristic, the elastic connection method can only bear load in one direction.

[0006] There is an urgent need for a double-nut ball screw pair that can carry loads in one or both directions and has small fluctuations in preload force when the middle diameter of the screw raceway increases and the lead accuracy changes. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to address the deficiencies in the above-mentioned prior art and provide a bidirectionally loaded double-nut ball screw pair and its operation control method and preload adjustment method, and a unidirectionally loaded nut ball screw pair, which can reduce the fluctuation of preload changes when the middle diameter of the screw raceway increases and the lead accuracy changes, and can effectively improve the smoothness of the screw pair's operation.

[0008] A first aspect of the present invention discloses a bidirectional load-bearing double-nut ball screw pair, comprising: a screw, a first nut, a first pre-tightening mechanism, a second pre-tightening mechanism, a second nut, and a nut seat;

[0009] Nut 1 and nut 2 are sleeved and mounted on the lead screw, and the nut seat supports the outer sides of nut 1 and nut 2, and the nut seat limits nut 1 and nut 2 in the axial direction;

[0010] The two ends of the nut seat are respectively equipped with a locking mechanism 1 and a locking mechanism 2;

[0011] The locking mechanism 1 is used to control the degree of freedom of the rotation direction of the nut 1;

[0012] The second locking mechanism is used to control the degree of freedom of the rotation direction of the second nut;

[0013] The pre-tightening mechanism includes a stop ring and an elastic member. The stop ring is coaxially mounted with the nut. The elastic member is mounted on the nut seat. The elastic member's expansion and contraction direction is perpendicular to the axis of the stop ring. The stop ring has a protruding structure, and one end of the elastic member rests on the protruding structure.

[0014] The second pre-tightening mechanism includes a second stop ring and a second elastic part. The second stop ring is coaxially installed with the second nut. The second elastic part is installed on the nut seat. The extension and contraction direction of the second elastic part is perpendicular to the axis of the second stop ring. The second stop ring has a protruding structure, and the second elastic part is supported on the protruding structure.

[0015] The above-mentioned bidirectionally loaded double-nut ball screw pair, the locking mechanism 1 is electromagnetic brake 1, and the locking mechanism 2 is electromagnetic brake 2; the front end of nut 1 is equipped with a connecting plate 1 fixed to the brake disc of electromagnetic brake 1, and the rear end of nut 2 is equipped with a connecting plate 2 fixed to the brake disc of electromagnetic brake 1.

[0016] The above-mentioned bidirectionally loaded double-nut ball screw pair, the elastic part 1 includes a guide cylinder, an adjusting nut, a disc spring group, a slider and a steel ball; the root of the guide cylinder is installed on the adjusting nut, the adjusting nut is threadedly connected to the stud, and the stud is detachably connected to the nut seat; the disc spring group and the slider are installed in the guide cylinder, the root of the disc spring group is connected to the root of the guide cylinder, the slider is connected to the front end of the disc spring group, the front end of the slider has a conical slot, the steel ball is located in the conical slot, the front side of the steel ball or the partial front side of the slider is outside the guide cylinder, and the steel ball is supported on the raised structure of the stop ring 1.

[0017] In the above-mentioned bidirectionally loaded double-nut ball screw pair, the elastic member 1 and the elastic member 2 have the same structure.

[0018] In the above-mentioned bidirectionally loaded double-nut ball screw pair, the first nut has a shoulder structure, thrust cylindrical roller bearings are arranged on both sides of the shoulder structure, and needle roller bearings are arranged on the circumferential side of the shoulder structure.

[0019] In the above-mentioned bidirectionally loaded double-nut ball screw pair, the second nut has a shoulder structure, thrust cylindrical roller bearings are arranged on both sides of the shoulder structure, and needle roller bearings are arranged on the circumferential side of the shoulder structure.

[0020] A second aspect of the present invention discloses an operation control method for the bidirectionally loaded double-nut ball screw pair as described in the first aspect, comprising the following steps:

[0021] Before the screw starts to run, the locking mechanism 1 is controlled to lock the nut 1 so that the nut 1 cannot rotate, and the locking mechanism 2 is controlled to lock the nut 2 so that the nut 2 cannot rotate;

[0022] Before the screw is switched from uniform speed to deceleration, the locking mechanism 1 is controlled to lock the nut 1 so that the nut 1 cannot rotate, and the locking mechanism 2 is controlled to lock the nut 2 so that the nut 2 cannot rotate.

[0023] The above operation control method includes the following steps:

[0024] After the screw starts running, if the nut 1 is the working nut, the locking mechanism 2 is controlled to open, so that the nut 2 can rotate;

[0025] After the lead screw starts to run, if the second nut is the working nut, the locking mechanism 1 is controlled to open, so that the first nut can rotate.

[0026] A third aspect of the present invention discloses a method for adjusting the preload force of the bidirectionally loaded double-nut ball screw pair described in the first aspect, comprising the following steps:

[0027] In the initial state, rotate nut 1 and nut 2 to make nut 1 and nut 2 reach the initial pre-tightened state;

[0028] Then, install the elastic member 1 and the elastic member 2, adjust the supporting force of the elastic member 1 and the elastic member 2, and rotate the nut 1 and the nut 2 in opposite directions by a certain angle to achieve preload adjustment.

[0029] In the above-mentioned preload adjustment method, after installing the elastic member 1 and the elastic member 2, only the supporting force of the elastic member 1 or the elastic member 2 is adjusted to rotate the nut 1 and the nut 2 in opposite directions by a certain angle to achieve preload adjustment.

[0030] A fourth aspect of the present invention discloses a unidirectional load-bearing nut ball screw pair, comprising: a screw, a nut, a pre-tightening mechanism, and a nut seat;

[0031] A nut set is installed on the screw, the nut seat supports the outer side of the nut, and the nut seat limits the nut in the axial direction;

[0032] One end of the nut seat is equipped with a locking mechanism 1;

[0033] The locking mechanism 1 is used to control the degree of freedom of the rotation direction of the nut 1;

[0034] The pre-tightening mechanism includes a stop ring and an elastic part. The stop ring is installed coaxially with the nut. The elastic part is installed on the nut seat. The expansion and contraction direction of the elastic part is perpendicular to the axis of the stop ring. The stop ring has a protruding structure, and one branch of the elastic part is pressed against the protruding structure.

[0035] Compared with the prior art, the present invention has the following advantages: there is no need to apply thrust to the nut in the axial direction to generate pre-tightening force as in the traditional pre-tightening method, but the pre-tightening force is generated by allowing the nut to rotate a certain angle in advance, and the pre-tightening force is maintained by keeping the nut in a pre-rotated state through the elastic member. When the middle diameter of the screw raceway increases and the lead accuracy changes, the elastic force of the elastic member is released to allow the nut to rotate a certain angle, thereby continuously maintaining the pre-tightening, and the pre-tightening force changes with small fluctuations, which can effectively improve the smoothness of the operation of the screw pair.

[0036] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a structural diagram of Example 1 of the present invention.

[0038] Figure 2 It is a structural schematic diagram of the pre-tightening mechanism of the present invention.

[0039] Figure 3 This is a schematic diagram of the principle of the nut 1 and the nut 2 in the pre-tightened state of the present invention.

[0040] Figure 4 This is a structural diagram of Example 4 of the present invention.

[0041] Description of the accompanying drawings:

[0042] 1—screw; 2—Nut 1; 3—Pre-tightening mechanism 1; 4—Pre-tightening mechanism 2; 5—Nut 2; 6—Nut seat; 7—Locking mechanism 1; 8—locking mechanism 2; 9—stop ring 1; 10—elastic member 1; 11—stop ring 2; 12—elastic member 2; 13—Connecting piece 1; 14—connecting piece 2; 15—Thrust cylindrical roller bearing; 16—needle roller bearing; 10-1—guide tube; 10-2—Adjusting nut; 10-3—disc spring set; 10-4—Slider; 10-5—Steel ball. DETAILED DESCRIPTION

[0043] Example 1:

[0044] like Figure 1As shown, a bidirectional load-bearing double-nut ball screw pair includes: a screw 1, a nut 2, a pre-tightening mechanism 3, a pre-tightening mechanism 4, a nut 5 and a nut seat 6; the nut 2 and the nut 5 are sleeved and installed on the screw 1, the nut seat 6 supports the outer sides of the nut 2 and the nut 5, and the nut seat 6 limits the nut 2 and the nut 5 in the axial direction; the two ends of the nut seat 6 are respectively installed with a locking mechanism 7 and a locking mechanism 8; the locking mechanism 7 is used to control the degree of freedom of the rotation direction of the nut 2; the locking mechanism 8 is used to control the degree of freedom of the rotation direction of the nut 5; the pre-tightening mechanism 3 includes a stop Ring 19 and elastic member 10, the stop ring 19 is coaxially installed with the nut 12, the elastic member 10 is installed on the nut seat 6, the expansion and contraction direction of the elastic member 10 is perpendicular to the axis of the stop ring 19, the stop ring 9 has a protruding structure, and the elastic member 10 is supported on the protruding structure; the pre-tightening mechanism 2 4 includes a stop ring 2 11 and elastic member 2 12, the stop ring 2 11 is coaxially installed with the nut 2 5, the elastic member 2 12 is installed on the nut seat 6, the expansion and contraction direction of the elastic member 2 12 is perpendicular to the axis of the stop ring 2 11, the stop ring 2 11 has a protruding structure, and the elastic member 2 12 is supported on the protruding structure.

[0045] In this embodiment, the locking mechanism 1 7 is the electromagnetic brake 1, and the locking mechanism 2 8 is the electromagnetic brake 2; the front end of the nut 1 2 is installed with a connecting piece 13 fixed to the brake disc of the electromagnetic brake 1, and the rear end of the nut 2 5 is installed with a connecting piece 2 14 fixed to the brake disc of the electromagnetic brake 1.

[0046] It should be noted that the advantage of using an electromagnetic brake in the locking mechanism is that it can achieve high-precision control and facilitate rapid switching between the locked and open states.

[0047] It should be clear to those skilled in the art that the locking mechanism may also be a structure similar to the clutch principle.

[0048] like Figure 2As shown, in this embodiment, the elastic member 10 includes a guide cylinder 10-1, an adjusting nut 10-2, a disc spring group 10-3, a slider 10-4 and a steel ball 10-5; the root of the guide cylinder 10-1 is installed on the adjusting nut 10-2, the adjusting nut 10-2 is threadedly connected to the stud, and the stud is detachably connected to the nut seat 6; the disc spring group 10-3 and the slider 10-4 are installed in the guide cylinder 10-1, the root of the disc spring group 10-3 is connected to the root of the guide cylinder 10-1, the slider 10-4 is connected to the front end of the disc spring group 10-3, the front end of the slider 10-4 has a conical slot, the steel ball 10-5 is located in the conical slot, the front side of the steel ball 10-5 or the partial front side of the slider 10-4 is outside the guide cylinder 10-1, and the steel ball 10-5 is supported on the raised structure of the stop ring 9.

[0049] In this embodiment, the elastic member 10 and the elastic member 2 12 have the same structure.

[0050] In actual use, the size of the supporting force is adjusted by adjusting the distance between the nut 10-2 and the raised structure of the stop ring, thereby indirectly adjusting the size of the preload force.

[0051] It should be noted that the guide cylinder can be a separate component, or the guide cylinder structure can be provided on the nut seat 6 by increasing the wall thickness of the nut seat.

[0052] In this embodiment, the nut 1 2 has a shoulder structure, thrust cylindrical roller bearings 15 are arranged on both sides of the shoulder structure, and needle roller bearings 16 are arranged on the circumferential side of the shoulder structure.

[0053] In this embodiment, the nut 2 5 has a shoulder structure, thrust cylindrical roller bearings 15 are arranged on both sides of the shoulder structure, and needle roller bearings 16 are arranged on the circumferential side of the shoulder structure.

[0054] It should be noted that, because both nut 1 2 and nut 2 5 may rotate with the screw 1, the nut has a shoulder structure, and thrust cylindrical roller bearings 15 are set on both sides of the shoulder structure to adapt to rotation and axial thrust, and needle roller bearings 16 are set on the circumferential side of the shoulder structure to adapt to rotation.

[0055] Example 2:

[0056] A method for controlling the operation of a bidirectionally loaded double-nut ball screw pair comprises the following steps:

[0057] Before the screw 1 starts to run, the locking mechanism 1 7 is controlled to lock the nut 1 2 so that the nut 1 2 cannot rotate, and the locking mechanism 2 8 is controlled to lock the nut 2 5 so that the nut 2 5 cannot rotate;

[0058] After the screw 1 starts to run, if the nut 2 is the working nut, the locking mechanism 8 is controlled to open, so that the nut 5 can rotate;

[0059] After the screw 1 starts to run, if the nut 2 5 is the working nut, the locking mechanism 1 7 is controlled to open, so that the nut 1 2 can rotate;

[0060] Before the screw 1 switches from a uniform speed to a decelerated speed, the locking mechanism 1 7 is controlled to lock the nut 1 2 so that the nut 1 2 cannot rotate, and the locking mechanism 2 8 is controlled to lock the nut 2 5 so that the nut 2 5 cannot rotate.

[0061] It should be noted that, considering the moment when the screw 1 starts running and the moment when it switches from uniform speed to deceleration, the nut seat 6 will have an inertial effect. Therefore, before and after the speed switch, the locking mechanism 1 7 and the locking mechanism 2 8 are both locked, so that the nut 1 2 and the nut 2 5 are rigidly connected to the nut seat 6 and cannot rotate, so that the pre-tightened position remains unchanged, thereby fully improving the operation accuracy of the nut seat 6.

[0062] Example 3:

[0063] like Figure 3 As shown, a method for adjusting the preload force of a bidirectionally loaded double-nut ball screw pair includes the following steps:

[0064] In the initial state, rotate nut 1 2 and nut 2 5 to make nut 1 2 and nut 2 5 reach the initial pre-tightened state;

[0065] Then, install the elastic member 10 and the elastic member 2 12, adjust the supporting force of the elastic member 10 and the elastic member 2 12, and rotate the nut 1 2 and the nut 2 5 in opposite directions by a certain angle to achieve preload adjustment.

[0066] It should be noted that in the initial state, the screw 1 is kept stationary and the nut 2 is rotated. During the rotation of the nut 2, it moves axially along the screw 1. Assuming that the nut 2 moves to the left, the balls of the nut 2 will be squeezed to the left side of the raceway and tightened, forming a pre-tightening; similarly, the nut 2 5 moves to the right, and the balls of the nut 2 5 will be squeezed to the right side of the raceway and tightened, forming a pre-tightening; in practice, because of the nut seat 6, when the nut 1 and the nut 2 5 are rotated in opposite directions at the same time, the nut 1 and the nut 2 5 can only rotate a small angle and cannot really move axially along the screw 1. They will only drive the balls to stick to one side of the raceway to form a pre-tightening. At this time, the elastic part 10 and the elastic part 2 12 are installed to keep the nut 1 and the nut 2 5 in the pre-tightening state to complete the pre-tightening. If the pre-tightening force needs to be adjusted, the supporting force of the elastic part 10 and the elastic part 2 12 can be adjusted to make the nut 2 and the nut 2 5 rotate in opposite directions by a certain angle to achieve pre-tightening force adjustment.

[0067] In this embodiment, after installing the elastic member 10 and the elastic member 2 12, only the supporting force of the elastic member 10 or the elastic member 2 12 is adjusted to rotate the nut 1 2 and the nut 2 5 in opposite directions by a certain angle to achieve preload adjustment.

[0068] It should be noted that the stop ring 1 9 and the stop ring 2 11 are located side by side between the nut 1 2 and the nut 2 5 , and the stop ring 1 9 is supported by the elastic member 10 to rotate in a direction opposite to the direction in which the stop ring 2 11 is supported by the elastic member 2 12 . As shown in the figure, when the stop ring 1 9 is supported by the elastic member 10 to rotate, the nut 1 2 will move to the left, and when the stop ring 2 11 is supported by the elastic member 2 12 to rotate, the nut 2 5 will move to the right.

[0069] After installing the elastic member 10 and the elastic member 2 12, only the elastic member 10 is adjusted. If the elastic member 10 is adjusted to increase the supporting force, the nut 1 2 is supported and rotated counterclockwise, with a tendency to move to the left. Under the connection of the nut seat 6, the nut 2 5 also has a tendency to move to the left. At this time, the nut 2 5 will rotate counterclockwise, and the stop ring 2 11 will rotate counterclockwise synchronously to compress the elastic member 2 12, indirectly adjusting the supporting force of the elastic member 2 12 on the stop ring; therefore, in practice, to adjust the preload force, only the supporting force of the elastic member 10 or the elastic member 2 12 can be adjusted.

[0070] Example 4:

[0071] like Figure 4 As shown, a unidirectionally loaded nut ball screw pair comprises: a screw 1, a nut 2, a pre-tightening mechanism 3 and a nut seat 6; the nut 2 is sleeved and mounted on the screw 1, the nut seat 6 supports the outer side of the nut 2, and the nut seat 6 limits the nut 2 in the axial direction; a locking mechanism 7 is mounted at one end of the nut seat 6; the locking mechanism 7 is used to control the degree of freedom of rotation direction of the nut 2; the pre-tightening mechanism 3 comprises a stop ring 9 and an elastic member 10, the stop ring 9 is coaxially mounted with the nut 2, the elastic member 10 is mounted on the nut seat 6, the extension and contraction direction of the elastic member 10 is perpendicular to the axis of the stop ring 9, the stop ring 9 has a protruding structure, and the elastic member 10 is supported on the protruding structure.

[0072] In this embodiment, the locking mechanism 7 is an electromagnetic brake; the front end of the nut 2 is equipped with a connecting piece 13 fixed to the brake disc of the electromagnetic brake.

[0073] In this embodiment, the elastic member 10 includes a guide cylinder 10-1, an adjusting nut 10-2, a disc spring group 10-3, a slider 10-4 and a steel ball 10-5; the root of the guide cylinder 10-1 is installed on the adjusting nut 10-2, the adjusting nut 10-2 is threadedly connected to the stud, and the stud is detachably connected to the nut seat 6; the disc spring group 10-3 and the slider 10-4 are installed in the guide cylinder 10-1, the root of the disc spring group 10-3 is connected to the root of the guide cylinder 10-1, the slider 10-4 is connected to the front end of the disc spring group 10-3, the front end of the slider 10-4 has a conical slot, the steel ball 10-5 is located in the conical slot, the front side of the steel ball 10-5 or the partial front side of the slider 10-4 is outside the guide cylinder 10-1, and the steel ball 10-5 is supported on the raised structure of the stop ring 9.

[0074] It should be noted that, when installing a unidirectionally loaded nut ball screw pair, assuming that the load-bearing running direction of the nut seat 6 is to move to the right, when the nut seat 6 and the nut 2 are installed on the leftmost end of the screw 1, the nut seat 6 is limited to the left side by an external device or the shoulder structure on the screw 1, and then the stop ring 9 is rotated to pre-tighten the nut 2, and then the elastic member 10 is installed to keep the nut 2 in a pre-tightened state.

[0075] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A double-nut ball screw pair with bidirectional load, characterized in that: include: Lead screw, nut 1, preload mechanism 1, preload mechanism 2, nut 2 and nut seat; Nut 1 and nut 2 are sleeved and mounted on the lead screw, and the nut seat supports the outer sides of nut 1 and nut 2, and the nut seat limits nut 1 and nut 2 in the axial direction; The two ends of the nut seat are respectively equipped with a locking mechanism 1 and a locking mechanism 2; The locking mechanism 1 is used to control the degree of freedom of the rotation direction of the nut 1; The second locking mechanism is used to control the degree of freedom of the rotation direction of the second nut; The pre-tightening mechanism 1 is used to support the nut 1 in the pre-tightening rotation direction; The second pre-tightening mechanism is used to support the second nut in the pre-tightening rotation direction; the first pre-tightening mechanism includes a first stop ring and a first elastic member, the first stop ring is coaxially installed with the nut, the first elastic member is installed on the nut seat, the expansion and contraction direction of the first elastic member is perpendicular to the axis of the first stop ring, the first stop ring has a protrusion structure, and the first elastic member is supported on the protrusion structure; The second pre-tightening mechanism includes a second stop ring and a second elastic member. The second stop ring is coaxially mounted with the second nut. The second elastic member is mounted on the nut seat. The expansion and contraction direction of the second elastic member is perpendicular to the axis of the second stop ring. The second stop ring has a protruding structure, and the second elastic member is supported on the protruding structure. The elastic part 1 includes a guide cylinder, an adjusting nut, a disc spring group, a slider and a steel ball; the root of the guide cylinder is installed on the adjusting nut, the adjusting nut is threadedly connected to the stud, and the stud is detachably connected to the nut seat; the disc spring group and the slider are installed in the guide cylinder, the root of the disc spring group is connected to the root of the guide cylinder, and the slider is connected to the front end of the disc spring group. The front end of the slider has a conical slot, and the steel ball is located in the conical slot. The front side of the steel ball or the partial front side of the slider is outside the guide cylinder, and the steel ball is supported on the protruding structure of the stop ring 1.

2. A bidirectionally loaded double-nut ball screw pair according to claim 1, characterized in that: The locking mechanism 1 is electromagnetic brake 1, and the locking mechanism 2 is electromagnetic brake 2; the front end of nut 1 is equipped with a connecting piece 1 fixed to the brake disc of electromagnetic brake 1, and the rear end of nut 2 is equipped with a connecting piece 2 fixed to the brake disc of electromagnetic brake 1.

3. A bidirectionally loaded double-nut ball screw pair according to claim 1, characterized in that: The nut 1 has a shoulder structure, thrust cylindrical roller bearings are arranged on both sides of the shoulder structure, and needle roller bearings are arranged on the circumferential side of the shoulder structure.

4. The operation control method of a bidirectionally loaded double-nut ball screw pair according to any one of claims 1 to 3, characterized in that: The following steps are involved: Before the screw starts to run, the locking mechanism 1 is controlled to lock the nut 1 so that the nut 1 cannot rotate, and the locking mechanism 2 is controlled to lock the nut 2 so that the nut 2 cannot rotate; Before the screw is switched from uniform speed to deceleration, the locking mechanism 1 is controlled to lock the nut 1 so that the nut 1 cannot rotate, and the locking mechanism 2 is controlled to lock the nut 2 so that the nut 2 cannot rotate.

5. The operation control method according to claim 4, characterized in that: The following steps are involved: After the screw starts running, if the nut 1 is the working nut, the locking mechanism 2 is controlled to open, so that the nut 2 can rotate; After the lead screw starts to run, if the second nut is the working nut, the locking mechanism 1 is controlled to open, so that the first nut can rotate.

6. A method for adjusting the preload force of a bidirectionally loaded double-nut ball screw pair according to any one of claims 1 to 3, characterized in that: The following steps are involved: In the initial state, rotate nut 1 and nut 2 to make nut 1 and nut 2 reach the initial pre-tightened state; Then, install the elastic member 1 and the elastic member 2, adjust the supporting force of the elastic member 1 and the elastic member 2, and rotate the nut 1 and the nut 2 in opposite directions by a certain angle to achieve preload adjustment.

7. The preload force adjustment method according to claim 6, characterized in that: After installing the elastic member 1 and the elastic member 2, only the supporting force of the elastic member 1 or the elastic member 2 is adjusted to rotate the nut 1 and the nut 2 in opposite directions by a certain angle to achieve preload adjustment.

8. A one-way loaded nut ball screw pair, characterized in that: include: Lead screw, nut one, preload mechanism one and nut seat; A nut set is installed on the screw, the nut seat supports the outer side of the nut, and the nut seat limits the nut in the axial direction; One end of the nut seat is equipped with a locking mechanism 1; The locking mechanism 1 is used to control the degree of freedom of the rotation direction of the nut 1; The pre-tightening mechanism 1 is used to support the nut 1 in the pre-tightening rotation direction; The pre-tightening mechanism includes a stop ring and an elastic member. The stop ring is coaxially mounted with the nut. The elastic member is mounted on the nut seat. The elastic member's expansion and contraction direction is perpendicular to the axis of the stop ring. The stop ring has a protruding structure, and one end of the elastic member rests on the protruding structure. The elastic part 1 includes a guide cylinder, an adjusting nut, a disc spring group, a slider and a steel ball; the root of the guide cylinder is installed on the adjusting nut, the adjusting nut is threadedly connected to the stud, and the stud is detachably connected to the nut seat; the disc spring group and the slider are installed in the guide cylinder, the root of the disc spring group is connected to the root of the guide cylinder, and the slider is connected to the front end of the disc spring group. The front end of the slider has a conical slot, and the steel ball is located in the conical slot. The front side of the steel ball or the partial front side of the slider is outside the guide cylinder, and the steel ball is supported on the protruding structure of the stop ring 1.

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