Ball screw pair servo mechanism with adjustable output angle and adjusting method thereof

Abstract

The present application relates to a kind of adjustable output angle ball screw pair servo mechanism and its adjusting method, belong to servo drive system technical field, solve the problem that the stroke of ball nut is difficult to limit and the volume of ball nut is large in prior art.The ball screw pair servo mechanism of the present application is cooperated with guide rail by the lug on the ball nut, and the ball nut is made to slide along the guide rail;When the trunnion on the ball nut moves, it can drive the output shaft to rotate.The displacement stroke of ball nut is limited by adjusting the position of the two limiting structures on the guide rail, and finally the maximum deflection angle of the output shaft is limited.The present application can avoid the problems of ball deformation or deviation from raceway, ball nut jamming and unable to return to zero or rudder out of control caused by the movement range of ball nut exceeding the maximum stroke.

Description

Technical Field

[0001] This invention relates to the field of servo drive system technology, and in particular to a ball screw pair servo mechanism with adjustable output angle and its adjustment method. Background Technology

[0002] As missile-mounted servo motors evolve towards miniaturization, the demand for efficient internal space utilization continues to increase. The fork-and-ball screw combination transmission system, with its compact structure and high transmission efficiency, is widely used in missile-mounted servo motors and other servo system transmission mechanisms. The ball screw combination mainly consists of a ball screw, a ball nut, and balls. Generally, the ball screw rotates, while the ball nut moves linearly under the guidance of a guide rail. The ball nut converts this linear motion into the rotational motion of the control surface via the fork. Depending on the missile's flight requirements, the control surface deflection range cannot exceed the maximum required deflection angle; therefore, the transmission mechanism needs to limit the control surface movement. This limiting method typically involves restricting the travel of the ball nut.

[0003] Currently, linear guidance and control surface limiting functions are implemented by different components, with the guide rail only used for linear guidance of the ball nut. Control surface limiting is generally achieved by increasing the outer diameter and axial length of the nut, allowing it to directly impact the ball screw's support frame or mounting bearing. This control surface limiting method increases the size and weight of the ball nut, resulting in low space utilization and hindering the miniaturization of the onboard servo mechanism. When the ball nut's stroke is close to its maximum stroke, the axial clearance of the bearing can cause the ball nut to move beyond its maximum stroke upon impact with the bearing, leading to ball deformation or deviation from the raceway. This can cause the ball nut to jam and become irreversible, ultimately resulting in servo malfunction. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide a solution to the problem that in existing ball screw nut pair servo mechanisms, when the ball nut's limit stroke is close to its maximum stroke, the ball nut's movement range exceeds the maximum stroke when it impacts the bearing. This causes the ball to deform or deviate from the raceway, resulting in the ball nut jamming and being unable to return to zero, which is an irreversible situation and ultimately leads to the servo motor losing control.

[0005] The objective of this invention is mainly achieved through the following technical solutions:

[0006] A ball screw servo mechanism with adjustable output angle includes: a screw, a ball nut, a guide rail, a connecting rod, and an output shaft; the screw, guide rail, and ball nut form a screw-nut pair; the ball nut is provided with lugs and trunnions; the lugs are capable of sliding relative to the guide rail; the guide rail is provided with a limiting structure for limiting the displacement stroke of the lugs; one end of the connecting rod is rotatably connected to the trunnion, and the other end is fixedly connected to the output shaft; the connecting rod is a telescopic connecting rod.

[0007] Furthermore, the limiting structure is a limiting sleeve.

[0008] Furthermore, the limiting sleeve is fitted onto the guide rail and can move relative to the guide rail.

[0009] Furthermore, the limiting sleeve and the guide rail are connected by threads.

[0010] Furthermore, the limiting structure is a limiting block; a groove is opened on the guide rail, and a slide rod is set in the groove; the slide rod passes through the groove, and limiting blocks are installed at both ends of the slide rod.

[0011] Furthermore, the limit block and the slide rod are connected by threads.

[0012] Furthermore, the linkage includes: a first linkage and a second linkage; the first linkage and the second linkage are nested together and are capable of relative movement.

[0013] Furthermore, the first connecting rod is connected to the trunnion via a bearing.

[0014] Furthermore, the second connecting rod is fixedly connected to the output shaft.

[0015] An adjustment method for a ball screw servo mechanism with adjustable output angle, employing the aforementioned ball screw servo mechanism, includes the following steps:

[0016] Step S1: Install the guide rail onto the guide rail bracket;

[0017] Step S2: The ball nut and the lead screw form a lead screw and nut pair; install the lead screw and nut pair into the servo mechanism, and make sure the lugs fit with the guide rail;

[0018] Step S3: Adjust the position of the upper limit structure of the guide rail to limit the displacement stroke of the ball nut.

[0019] The technical solution of this invention can achieve at least one of the following effects:

[0020] 1. This invention, by adding a limiting structure to the guide rail, can limit the maximum stroke of the ball nut to the left and / or right, thereby limiting the maximum deflection angle of the output axis to the left or right. By controlling the displacement stroke of the ball nut, it avoids the ball nut's movement range from exceeding the maximum stroke, which would cause the ball to deform or deviate from the raceway, resulting in the ball nut jamming and being unable to return to zero, ultimately leading to the loss of control of the servo motor.

[0021] The ball screw pair guide limit mechanism of the present invention limits the stroke of the ball nut by installing a limit structure on the guide rail, which requires increasing the width of the ball nut. This solves the problems of increased volume and weight of the ball nut and easy jamming, and avoids the loss of control of the servo motor due to the ball nut jamming.

[0022] 2. This invention utilizes the combination of lugs and nylon guide belts, taking advantage of the compressibility, wear resistance, and low coefficient of friction of the nylon guide belts. This eliminates the transmission gap caused by material wear between the lugs and the guide rails without affecting the transmission efficiency. This avoids problems such as low deflection accuracy, poor small signal tracking capability, and system jitter caused by transmission gaps, thus improving the stability of the system.

[0023] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0024] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0025] Figure 1 This is a schematic diagram of the servo mechanism structure for ball screw drive;

[0026] Figure 2 This invention relates to a ball screw pair servo mechanism with adjustable output angle.

[0027] Figure 3 Partial cross-sectional view of the ball screw pair servo mechanism with adjustable output angle of the present invention. Figure 1 ;

[0028] Figure 4 Partial cross-sectional view of the ball screw pair servo mechanism with adjustable output angle of the present invention. Figure 2 ;

[0029] Figure 5 This is a schematic diagram of a ball nut structure;

[0030] Figure 6 This is a schematic diagram of the guide rail structure;

[0031] Figure 7 Schematic diagram of the installation of ball nuts and nylon guide strips;

[0032] Figure 8 Exploded view of ball nut and nylon guide belt;

[0033] Figure 9 This is a schematic diagram of the locked version structure.

[0034] Figure label:

[0035] 1-Lead screw; 2-Ball nut; 3-Tube shaft; 4-Connecting rod; 5-Output shaft; 6-Guide rail; 7-Support lug; 8-Limit sleeve; 9-Guide rail bracket; 10-Locking plate; 11-Locking boss; 12-Locking groove; 13-Screw; 14-Bearing; 15-Nylon guide belt; 41-First connecting rod; 42-Second connecting rod. Detailed Implementation

[0036] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0037] Example 1

[0038] A specific embodiment of the present invention, such as Figure 1-9 As shown, a ball screw pair servo mechanism with adjustable output angle is disclosed, including: screw 1, ball nut 2, guide rail 6, connecting rod 4 and output shaft 5, wherein screw 1 and ball nut 2 form a screw-nut pair.

[0039] Furthermore, such as Figure 1 As shown, the ball nut 2 is provided with a lug 7 and a trunnion 3. The lug 7 is provided with a U-shaped groove, which engages with the guide rail 6 and allows for relative sliding. The trunnion 3 is connected to the connecting rod 4 via a bearing 14, and the connecting rod 4 is a telescopic structure. One end of the connecting rod 4 is rotatably connected to the trunnion 3, and the other end is fixedly connected to the output shaft 5. The output shaft 5 can rotate along its own axis.

[0040] The ball nut 2 is machined with lugs 7. The lugs 7 mainly have U-shaped grooves and limiting surfaces on both sides. The U-shaped grooves are used to mate with the cylindrical surface of the guide rail 6 (line contact), and the limiting surfaces are used to rigidly contact the shoulders on the guide rail 6, thereby limiting the displacement stroke of the ball nut 2.

[0041] When the lead screw 1 rotates, the ball nut 2 slides along the guide rail 6, the trunnion 3 moves synchronously with the ball nut, and the trunnion 3 drives the output shaft 5 to rotate through a certain angle through the connecting rod 4.

[0042] In one specific embodiment of the present invention, the connecting rod 4 includes: a first connecting rod 41 and a second connecting rod 42.

[0043] Furthermore, the first link 41 and the second link 42 are interlocked and can slide relative to each other. For example... Figure 1 , Figure 4 As shown, the upper part of the first connecting rod 41 is provided with a bearing mounting hole, and the lower part is a cylindrical structure; the upper part of the second connecting rod 42 is a cylindrical structure, and the lower part is connected to the output shaft 5. Furthermore, the second connecting rod 42 and the output shaft 5 are fixedly connected by welding or bolts.

[0044] Furthermore, the trunnion 3 is mounted in the bearing mounting hole of the first connecting rod 41 via a bearing. The trunnion 3 is connected to the inner ring of the bearing 14 by an interference fit; the first connecting rod 41 is fitted to the outer ring of the bearing 14 by an interference fit.

[0045] When the trunnion 3 and the ball nut 2 slide, the trunnion 3 rotates relative to the first connecting rod 41, and at the same time drives the first connecting rod 41 and the second connecting rod 42 to slide relative to each other; the connecting rod 4 extends and retracts and deflects at an angle, and the trunnion 3 drives the output shaft 5 to deflect at an angle through the connecting rod 4.

[0046] The length of the working section of the guide rail 6 of the present invention is adjustable. By adjusting the length of the working section that cooperates with the lug 7 of the ball nut 2, the displacement distance of the trunnion 3 can be adjusted, thereby realizing the adjustment of the maximum deflection angle of the output shaft 5 to the left or right.

[0047] In one specific embodiment of the present invention, two limiting structures are installed on the guide rail 6, and the support ear 7 is engaged on the guide rail 6 through a U-shaped groove and located between the two limiting structures; the limiting structures are used to block the support ear 7 from continuing to move, thereby adjusting the length of the working section, and finally realizing the adjustment of the maximum deflection angle of the output shaft 5.

[0048] In this invention, the limiting structure is: a limiting sleeve 8 or a limiting block (not shown in the figure).

[0049] 1) When the limiting structure is a limiting sleeve 8:

[0050] In one specific embodiment of the present invention, such as Figure 2 , Figure 3 As shown, the limiting sleeve 8 is fitted on the guide rail 6 and can move relative to the guide rail 6.

[0051] Furthermore, the width of the limiting sleeve 8 is greater than the width of the U-shaped groove of the lug 7. The limiting sleeve 8 can prevent the ball nut 2 from continuing to slide, thereby controlling the output angle of the output shaft 5.

[0052] Furthermore, the limiting sleeve 8 is connected to the guide rail 6 by threads. The guide rail 6 has external threads, and the limiting sleeve 8 has internal threads. The limiting sleeve 8 is installed on the guide rail 6 by threads.

[0053] By rotating the limiting sleeve 8, the position of the limiting sleeve 8 on the guide rail 6 can be adjusted, thereby limiting the sliding distance of the support lug 7 on the guide rail 6. The support lug 7, the ball nut 2, and the trunnion 3 are all integral structures, and the maximum deflection angle of the output shaft 5 can be controlled by controlling the movement distance of the trunnion 3.

[0054] 2) When the limiting structure is a limiting block:

[0055] In another specific embodiment of the present invention, a groove is formed on the guide rail 6, the groove extends vertically through the guide rail 6, and the length of the groove is equal to the distance between the inner sides of the guide rail bracket 9.

[0056] Furthermore, a sliding rod is installed in the slide groove. The sliding rod is a threaded rod, and limit blocks are installed at both ends of the sliding rod, that is, limit blocks are installed on the upper and lower sides of the guide rail 6. The limit blocks are provided with threaded holes, and the limit blocks are installed on the sliding rod through the threaded holes. Rotating the limit blocks at both ends makes them clamp onto the guide rail 6, thereby fixing the position of the limit blocks on the guide rail 6.

[0057] Furthermore, the width of the limiting block is greater than the width of the U-shaped groove of the support lug 7.

[0058] Furthermore, two sets of limit blocks are installed on the guide rail 6.

[0059] Specifically, there are two slide rods in the slide groove, and limit blocks are installed at both ends of the slide rods. There are four limit blocks in total, two in a group, installed at both ends of the slide rods. The slide rod moves the two groups of limit blocks to their installation positions, and the limit blocks are tightened. The guide rail 6 is clamped between the two limit blocks, and the displacement stroke of the support lug 7 is limited by the limit blocks. In turn, the maximum deflection angle of the output shaft 5 is limited by limiting the displacement range of the trunnion 3.

[0060] Furthermore, a scale is set on the guide rail 6 to mark the position of the limit block.

[0061] The length of the working section of the guide rail 6 is the distance between the two sets of limit blocks. By adjusting the position of the first set of limit blocks on the guide rail 6 and the position of the second set of limit blocks on the guide rail 6, the maximum displacement of the ball nut 2 to the left or right can be adjusted, thereby adjusting the maximum deflection angle of the output shaft 5 to the left or right.

[0062] The ball screw pair guide limit mechanism of the present invention limits the stroke of the ball nut by installing a limit structure on the guide rail, which requires increasing the width of the ball nut. This solves the problems of increased volume and weight of the ball nut and easy jamming, and avoids the loss of control of the servo motor due to the ball nut jamming.

[0063] In one specific embodiment of the present invention, the guide rail 6 is mounted on the guide rail bracket 9 via a locking plate 10. The locking plate 10 has two countersunk holes and a locking boss 11, which are used to fix the locking plate 10 and the guide rail 6, respectively.

[0064] Furthermore, the diameter of the mounting hole on the left side of the guide rail bracket 9 is larger than the maximum diameter of the guide rail 6, meaning that the guide rail 6 can pass entirely through the mounting hole on the left side of the guide rail bracket 9. The diameter of the mounting hole on the right side of the guide rail bracket 9 is smaller than the diameter of the working section of the guide rail 6, and the end of the guide rail 6 is engaged in the mounting hole on the right side of the guide rail bracket 9, restricting the axial displacement of the guide rail 6.

[0065] Furthermore, the locking plate 10 is fixedly mounted on the guide rail bracket 9 by screws 13.

[0066] Furthermore, the locking boss 11 is a straight boss, and correspondingly, the end of the guide rail 6 is provided with a locking groove 12. The locking boss 11 and the locking groove 12 cooperate to restrict the guide rail 6 from deflecting relative to the guide rail bracket 9. During installation, the guide rail 6 passes through the mounting hole on the left side of the guide rail bracket 9 and is inserted into the mounting hole on the right side. The locking plate 10 is fixed to the guide rail bracket 9 by screws 13, and the locking boss 11 is inserted into the locking groove 12.

[0067] With prolonged use of the servo mechanism, material wear caused by sliding friction between the lug 7 and the guide rail 6, and between the shift fork 4 and the trunnion 3, can easily lead to gaps. This can cause transmission gaps between the two, resulting in dead zones in the servo mechanism system, affecting the servo system's deflection accuracy and small signal tracking capability, and in severe cases, causing system jitter.

[0068] In one specific embodiment of the present invention, an elastic buffer is provided between the lug 7 and the guide rail 6. The elastic buffer eliminates transmission gaps and ensures the accuracy and stability of the system transmission.

[0069] Preferably, the elastic buffer is made of nylon.

[0070] Furthermore, the lug 7 is provided with a nylon guide strip, which contacts the guide rail 6. Specifically, a nylon mounting groove is formed on the lug 7; the nylon guide strip is installed in the nylon mounting groove and protrudes from the surface of the U-shaped groove of the lug 7.

[0071] The nylon guide belt is U-shaped. The width 'a' of the U-shaped groove of the nylon guide belt is smaller than the width 'b' of the U-shaped groove of the support lug 7. Generally, 0 < ba ≤ 0.8 mm. This value can be adjusted appropriately according to the load conditions of the servo system, but the nylon guide belt cannot exceed the yield strength of the nylon material after compression.

[0072] Since the width of the working section of guide rail 6 is basically the same as the width of the U-shaped groove of the support lug 7 (the clearance on one side is generally no more than 0.01mm), after the ball screw assembly is completed, the guide rail 6 compresses and deforms the nylon guide belt during transmission. Utilizing the compressibility of nylon material, when the ball nut 2 moves linearly, the nylon guide belt and guide rail 6 remain tightly fitted, with the ball nut 2 sliding relative to the guide rail 6 without clearance. Taking advantage of the wear resistance and low coefficient of friction of nylon material, the sliding friction between the nylon guide belt and the guide rail is small, and the material is not easily worn, resulting in a long service life. This achieves the goal of eliminating system dead zones without affecting transmission efficiency and working time.

[0073] This invention eliminates the gap between the lug 7 and the guide rail 6 by setting a nylon guide belt, thereby improving the deflection accuracy, small signal tracking capability and stability of the servo system.

[0074] In practice, the displacement stroke of the ball nut 2 is limited by adjusting the position of the two limiting structures (limiting sleeve 8 or limiting block) on the guide rail 6, which ultimately limits the maximum deflection angle of the output shaft 5.

[0075] In the initial position, the ball nut 2 is located in the middle position of the lead screw 1, that is, the central axis of the ball nut 2 is vertically aligned with the central axis of the output shaft 5, as shown below. Figure 1 As shown.

[0076] When the lead screw 1 rotates, the ball nut 2 is circumferentially limited by the guide rail 6 and cannot rotate. The ball nut 2 slides relative to the lead screw 1 and the guide rail 6. When the ball nut 2 slides along the guide rail 6, the trunnion 3 also slides horizontally synchronously. The trunnion 3 is connected to the first connecting rod 41 of the connecting rod 4 through the bearing 14. During the sliding process of the trunnion 3, the first connecting rod 41 deflects at an angle relative to the trunnion 3, and the first connecting rod 41 slides relative to the second connecting rod 42. The length of the connecting rod 4 changes, and the second connecting rod 42 deflects synchronously under the drive of the first connecting rod 41. The second connecting rod 42 is fixed to the output shaft 5 and can drive the output shaft to rotate.

[0077] When the ball nut 2 slides to both sides, the lug 7 above the ball nut 2 is blocked by the upper limit structure (limiting sleeve 8 or limiting block) of the guide rail 6. The displacement stroke of the ball nut 2 is limited by the limiting sleeve 8 or limiting block. The maximum deflection angle of the output shaft is adjusted by limiting the displacement stroke of the trunnion 3.

[0078] Example 2

[0079] Another specific embodiment of the present invention provides an adjustment method for a ball screw pair servo mechanism with adjustable output angle according to Embodiment 1, which limits the displacement stroke of the ball nut 2 and controls the maximum deflection angle of the output shaft 5, specifically including the following steps:

[0080] Step S1: Install the guide rail 6 onto the guide rail bracket 9;

[0081] Step S2: The ball nut 2 and the lead screw 1 form a lead screw and nut pair; the lead screw and nut pair is installed into the servo mechanism, and the lug 7 is engaged with the guide rail 6;

[0082] Step S3: Adjust the position of the upper limit structure of the guide rail 6 to limit the displacement stroke of the ball nut 2.

[0083] In step S1, the mounting hole on the left side of the guide rail bracket 9 allows the guide rail 6 to pass through, while the mounting hole on the right side only allows the small-diameter mounting part at the right end of the guide rail 6 to pass through.

[0084] During installation, the guide rail 6 first passes through the mounting hole on the left side of the guide rail bracket 9, and two sets of limiting structures are installed on the guide rail 6; the guide rail 6 is then moved to engage with the mounting hole on the right side of the guide rail bracket 9; a locking plate 10 is installed on the guide rail bracket 9 and secured with screws 13; the locking boss 11 of the locking plate 10 engages with the locking groove 12 of the guide rail 6, and the locking plate 10 prevents the guide rail 6 from deflecting on the guide rail bracket 9.

[0085] Furthermore, when the limiting structure is a limiting sleeve 8: two limiting sleeves 8 are installed in sequence, the limiting sleeve 8 is rotated and connected to the guide rail 6 by threads, and the position of the limiting sleeve 8 is adjusted.

[0086] When the limiting structure is a limiting block: pass the slide rod through the slide groove on the guide rail 6, adjust the installation position of the slide rod and tighten the limiting blocks at both ends of the slide rod. The two limiting blocks clamp the guide rail 6 to complete the installation of the limiting blocks.

[0087] In step S2, the working section between the two sets of limiting structures of the guide rail 6 is engaged in the U-shaped groove of the support lug 7.

[0088] In step S3, the position of the limiting structure on the guide rail 6 is adjusted to adjust the stroke of the ball nut 2;

[0089] Specifically, when the limiting structure is the limiting sleeve 8: rotate the limiting sleeve 8 to adjust the position of the limiting sleeve 8 on the guide rail 6.

[0090] When the limiting structure is a limiting block: rotate the limiting block to move it relative to the slide rod, loosen the limiting block, slide the slide rod in the slide groove to adjust the position of the limiting block, and tighten the limiting block to complete the fixing of the limiting block on the guide rail 6.

[0091] Furthermore, the lead screw 1 is driven to rotate by the motor. When the lead screw 1 rotates, the ball nut 2 slides along the guide rail 6, and at the same time, the trunnion 3 drives the connecting rod 4 and the output shaft 5 to deflect. The limiting sleeve 8 or the limiting block of the limiting structure can limit the displacement stroke of the ball nut 2, thereby adjusting the maximum deflection angle of the output shaft 5.

[0092] When the trunnion 3 slides along the guide rail 6, the trunnion 3 rotates relative to the first connecting rod 41. At the same time, the first connecting rod 41 and the second connecting rod 42 slide relative to each other. Through the extension and rotation of the connecting rod 4, the output shaft 5 is deflected, thereby realizing the angular displacement output of the servo mechanism.

[0093] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A ball screw pair servo mechanism with adjustable output angle, characterized in that, include: The components are: a lead screw (1), a ball nut (2), a guide rail (6), a connecting rod (4), and an output shaft (5); the lead screw (1), the guide rail (6), and the ball nut (2) form a lead screw and nut pair; the ball nut (2) is provided with a lug (7) and a trunnion (3); the lug (7) can slide relative to the guide rail (6); the guide rail (6) is provided with a limiting structure for limiting the displacement stroke of the lug (7); one end of the connecting rod (4) is rotatably connected to the trunnion (3), and the other end is fixedly connected to the output shaft (5); the connecting rod (4) is a telescopic connecting rod; the limiting structure is used to block the continued movement of the lug (7), thereby adjusting the length of the working section, and finally realizing the adjustment of the maximum deflection angle of the output shaft (5); The connecting rod (4) includes: a first connecting rod (41) and a second connecting rod (42); the first connecting rod (41) and the second connecting rod (42) are sleeved on each other and can move relative to each other; the first connecting rod (41) is connected to the trunnion (3) through a bearing (14); the second connecting rod (42) is fixedly connected to the output shaft (5); the upper part of the first connecting rod (41) is provided with a bearing mounting hole, and the lower part is a cylindrical structure; the upper part of the second connecting rod (42) is a cylindrical structure; the trunnion (3) is installed in the bearing mounting hole of the first connecting rod (41) through a bearing; when the trunnion (3) slides synchronously with the ball nut (2), the trunnion (3) rotates relative to the first connecting rod (41), and at the same time drives the first connecting rod (41) and the second connecting rod (42) to slide relative to each other; the connecting rod (4) extends and retracts and undergoes angular deflection, and the trunnion (3) drives the output shaft (5) to undergo angular deflection through the connecting rod (4); The limiting structure is a limiting sleeve (8); the limiting sleeve (8) is sleeved on the guide rail (6) and can move relative to the guide rail (6); the limiting sleeve (8) and the guide rail (6) are connected by threads; the width of the limiting sleeve (8) is greater than the width of the U-shaped groove of the lug (7); the limiting sleeve (8) can prevent the ball nut (2) from continuing to slide, thereby controlling the output angle of the output shaft (5); by rotating the limiting sleeve (8), the position of the limiting sleeve (8) on the guide rail (6) can be adjusted, thereby limiting the sliding distance of the lug (7) on the guide rail (6) by the limiting sleeve (8); Alternatively, the limiting structure is a limiting block; a groove is opened on the guide rail (6), and a sliding rod is set in the groove; the sliding rod passes through the groove, and limiting blocks are installed at both ends of the sliding rod; the limiting blocks and the sliding rod are connected by threads; the limiting blocks at both ends are rotated to clamp them on the guide rail (6), thereby fixing the position of the limiting blocks on the guide rail (6); the width of the limiting block is greater than the width of the U-shaped groove of the support lug (7); two sets of limiting blocks are installed on the guide rail (6); The support ear (7) is provided with a nylon guide strip (15) and contacts the guide rail (6) through the nylon guide strip; a nylon mounting groove is opened on the support ear (7); the nylon guide strip (15) is installed in the nylon mounting groove and protrudes from the surface of the U-shaped groove of the support ear (7).

2. A method for adjusting a ball screw servo mechanism with adjustable output angle, using the ball screw servo mechanism as described in claim 1, comprising the following steps: Step S1: Install the guide rail (6) onto the guide rail bracket (9); Step S2: The ball nut (2) and the lead screw (1) form a lead screw and nut pair; the lead screw and nut pair is installed in the servo mechanism, and the lug (7) is engaged with the guide rail (6); Step S3: Adjust the position of the upper limit structure of the guide rail (6) to limit the displacement stroke of the ball nut (2).

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