Ball screw pair anti-rotation mechanism based on involute guide rail pre-embedding

Abstract

The utility model discloses a ball screw pair anti-rotation mechanism based on involute guide rail pre-embedding, which comprises a valve block, the valve block is connected with one end of an anti-rotation sleeve through a fastener, a nut is sleeved in the anti-rotation sleeve, the outer cylindrical surface of the nut is uniformly provided with at least two sections of grooves, the lower end of an involute guide rail is provided with a square key, and the involute guide rail is embedded in the square key. The square key is in transition fit with the groove, involute grooves matched with the involute guide rails in number are formed in the cylindrical surface of the inner side of the anti-rotation sleeve, the involute grooves are in clearance fit with the upper ends of the involute guide rails, the involute guide rails are used for preventing the nut from rotating, and the nut is connected with the lead screw through threads. The anti-rotation mechanism is stable in dynamic characteristic, low in noise and high in reliability, and the problems of response delay, thermal deformation, cylinder collision and the like of a traditional anti-rotation mechanism are successfully solved through the collaborative design that the involute guide rail is embedded, the petal type flange is adopted and the blind blocking limiting structure is arranged.

Description

Technical Field

[0001] This utility model relates to an anti-rotation mechanism for a ball screw pair based on an involute guide rail, and particularly to the field of automotive brake-by-wire technology. Background Technology

[0002] In automotive brake-by-wire systems, the ball screw, as a core transmission component, directly affects braking response speed, accuracy, and reliability. However, the anti-rotation mechanism of the ball screw used in traditional brake-by-wire systems suffers from several industry pain points that urgently need to be addressed:

[0003] Response delay: Traditional anti-rotation structures have tiny gaps, which cause a delay in the initial braking phase (about 15-20ms). This delay seriously affects the triggering time of the AEB (Automatic Emergency Braking) system and poses a potential threat to driving safety.

[0004] Poor thermal stability: During frequent braking, when the system temperature rises above 120℃, traditional plastic guides are prone to deformation. Taking nylon guides as an example, the measured deformation can reach 0.3mm, which will lead to a decrease in guiding accuracy and thus affect braking performance.

[0005] Space constraints: The installation space of the car chassis is demanding, and the traditional anti-rotation structure occupies a large axial space, usually ≥25mm, which exceeds the design boundary of the EMA module and brings great difficulties to the system integration and layout.

[0006] Durability issues: Under urban driving conditions, the average number of braking cycles exceeds 500,000 per year, and the existing anti-rotation structure suffers from severe wear. Actual measurement data shows that the wear depth of the guide groove exceeds the tolerance of 50μm, which not only reduces the service life of the mechanism but also affects the stability of the braking system. Utility Model Content

[0007] This invention provides an anti-rotation mechanism for a ball screw pair based on an involute guide rail, which overcomes the defects of anti-rotation mechanisms in existing linear control braking systems, such as response delay, thermal deformation, and cylinder collision.

[0008] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0009] This utility model discloses an anti-rotation mechanism for a ball screw pair based on an involute guide rail pre-embedded in an involute guide rail. The mechanism includes a valve block, one end of which is connected to an anti-rotation sleeve via fasteners. A nut is fitted into the anti-rotation sleeve. The nut has at least two grooves evenly spaced on its outer cylindrical surface. A square key is provided at the lower end of the involute guide rail, and the square key and the grooves are fitted together. The anti-rotation sleeve has involute grooves on its inner cylindrical surface, the number of which matches the number of involute guide rails. The involute grooves are fitted with the upper end of the involute guide rails with a clearance fit. The involute guide rails are used to prevent the rotation of the nut. A lead screw is threaded into the nut.

[0010] Furthermore, the two ends of the groove are equipped with blind plug structures to prevent the involute guide rail from moving bidirectionally along the axial direction of the groove, thus serving as a limiting function.

[0011] Furthermore, a tangential step surface is provided on the outer side of the groove, and the tangential step surface has a protruding part, which is used to fix the involute guide rail in the groove to complete the rigid connection.

[0012] Furthermore, the inner wall of the nut is provided with an internal thread, which is tightly connected to the spiral raceway of the lead screw. The balls roll on the internal thread of the nut and the outer spiral raceway of the lead screw, so that the lead screw drives the nut to rotate through rolling friction, thereby realizing the transmission of power.

[0013] Furthermore, the groove of the anti-rotation sleeve is configured as a blind plug structure on the outside to limit the movement and prevent the nut from hitting the bottom of the cylinder.

[0014] Furthermore, one end of the anti-rotation sleeve is equipped with evenly distributed petal-shaped flanges, which engage with the petal-shaped flange notches on the side of the valve block.

[0015] Furthermore, the fastener is a rivet, and the outer diameter of the rivet is equipped with a rubber sleeve, with the two being clearance-fitted.

[0016] Furthermore, the rivets pass through the mounting through holes of the anti-rotation sleeve and are then pressed into the blind holes of the valve block, so that the anti-rotation sleeve is fixedly connected to the valve block.

[0017] Furthermore, the involute guide rail and the groove of the anti-rotation sleeve are in involute-shaped surface contact, which is used to convert the rotational motion of the lead screw into the linear motion of the lead nut.

[0018] The beneficial effects achieved by this utility model are as follows: Three convex involute guide rails are pre-embedded on the outer cylindrical surface of the lead screw nut, and these guide rails cooperate with three grooves on the inner wall of the anti-rotation sleeve, efficiently converting the rotational motion of the lead screw into the linear motion of the lead screw nut. Integrating the anti-rotation mechanism with the nut significantly improves the rigidity and transmission accuracy of the system. Simultaneously, the involute guide rails and the grooves on the anti-rotation sleeve use an involute surface contact, which features low contact stress, high guiding accuracy, and good rigidity, effectively improving the transmission performance of the mechanism. Furthermore, the grooves on the inner wall of the anti-rotation sleeve are configured as a blind-blocking structure, which provides precise limiting when the lead screw nut returns to the motor's zero position at a uniform speed. Especially in the event of an unexpected power failure, this effectively prevents the lead screw nut from directly impacting the cylinder bottom, avoiding functional failures in the motor and braking system, completely solving the industry pain point of impacting the cylinder bottom, and significantly improving the reliability and safety of the braking system. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is an exploded view of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of this utility model;

[0022] Figure 3 This is a schematic diagram of the anti-rotation sleeve of this utility model;

[0023] Figure 4 This is a schematic diagram of the installation of the involute guide rail and the groove of this utility model;

[0024] Figure 5 This is a schematic diagram of the installation of the valve block and anti-rotation sleeve of this utility model.

[0025] In the diagram: 1. Valve block; 2. Rubber sleeve; 3. Rivet; 4. Lead screw; 5. Nut; 6. Involute guide rail; 7. Anti-rotation sleeve. Detailed Implementation

[0026] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0027] Example 1

[0028] like Figure 1-5As shown, a ball screw anti-rotation mechanism based on an involute guide rail pre-embedded in the ball screw pair includes a valve block 1. The valve block 1 is connected to one end of the anti-rotation sleeve 7 by a fastener. The nut 5 is fitted into the anti-rotation sleeve 7. The two are in contact through the involute guide rail 6. The involute guide rail 6 is used to prevent the rotation of the nut 5. The nut 5 is threadedly connected to a screw rod 4.

[0029] The nut 5 has three evenly spaced grooves on its outer cylindrical surface, which transition into the square key at the lower end of the involute guide rail 6, with a tolerance zone of H7 / k6 (GB / T 1800.2). A professional riveting tool is used to precisely press the involute guide rail 6 into the grooves of the nut, achieving initial guiding and fixing connection and ensuring the accurate positioning of the involute guide rail 6 on the nut 5.

[0030] The groove is equipped with blind plugs at both ends to provide precise positioning. The positioning tolerance is configured to have a zero-position error of ≤ ±0.05mm, which effectively prevents the involute guide rail 6 from moving bidirectionally along the axial direction of the groove, ensuring the stability and reliability of the mechanism.

[0031] The nut 5 has tangential stepped surfaces on the outer sides of the three grooves. These stepped surfaces are plastically deformed by a wedge-shaped riveting head, forming protrusions. These protrusions firmly fix the involute guide rail 6 within the grooves, completing the final rigid connection. This connection method features both high guiding accuracy and good rigidity, effectively improving the overall performance of the mechanism.

[0032] The inner wall of the nut 5 is provided with an internal thread, and balls are arranged in the internal thread, which are tightly connected to the outer helical raceway of the lead screw 4. When the motor rotor drives the lead screw 4 to rotate in both directions, the balls will roll simultaneously on the internal thread of the nut 5 and the outer helical raceway of the lead screw 4. The lead screw 4 drives the nut 5 to rotate through rolling friction, realizing the effective transmission of power.

[0033] The anti-rotation sleeve 7 has three involute grooves on its inner cylindrical surface, which are respectively fitted with the involute guide rail 6 with clearance. This fit effectively prevents the screw nut 5 from rotating, and the axial component of the rolling friction causes the screw nut 5 to reciprocate linearly along the screw, thus achieving a perfect conversion from rotational motion to linear motion. Since the tangential component of the anti-rotation force uses involute surface contact, it has the characteristics of low contact stress, high guiding accuracy, and good rigidity, which can significantly improve the transmission performance of the mechanism.

[0034] The lower end of the anti-rotation sleeve 7 is equipped with evenly distributed petal-shaped flanges, which engage with the petal-shaped flange notches of the valve block 1. During assembly, the petal-shaped flanges of the anti-rotation sleeve 7 are accurately aligned with the petal-shaped flange notches of the valve block 1, and the anti-rotation sleeve 9 is inserted before clockwise rotation is performed until the mounting holes of the anti-rotation sleeve 7 and the mounting holes of the valve block 1 are precisely aligned. The petal-shaped flange engagement provides high connection rigidity. When the nut 5 directly impacts the bottom of the cylinder, it can effectively prevent the anti-rotation sleeve 7 from being dislodged or broken by the instantaneous impact of the involute guide rail, ensuring the safety and reliability of the mechanism.

[0035] When the anti-rotation sleeve 7 is connected to the valve block 1, the three rivets 3 pass through the mounting through holes of the anti-rotation sleeve 7 and are precisely pressed into the blind holes of the valve block 1 to achieve a firm fixed connection and ensure that the connection between the anti-rotation sleeve 7 and the valve block 1 is tight and reliable.

[0036] The fastener is a rivet 3, and the outer diameter of the rivet 3 is fitted with a rubber sleeve 2, with the two in a clearance fit. When the anti-rotation sleeve 7 changes direction instantaneously, it will generate an impact force on the valve block 1. At this time, the rubber sleeve 2 can play a good buffering role, reducing the impact force damage to the valve block 1 and extending the service life of the mechanism.

[0037] Three outwardly convex involute guide rails 6 are evenly embedded on the outer cylindrical surface of the lead screw nut 5, so that they precisely fit with the three grooves on the inner wall of the anti-rotation sleeve 7. This converts the rotational motion of the lead screw 4 into the linear motion of the lead screw nut 5, and integrates the anti-rotation mechanism with the nut, significantly improving the rigidity and transmission accuracy of the system.

[0038] The grooves of the involute guide rail 6 and the anti-rotation sleeve 7 are involute-shaped surface contacts with an involute radius of curvature R = 3mm ± 0.01mm. This contact method has significant advantages such as low contact stress and high guiding accuracy, which can effectively improve the transmission stiffness. According to the test, the transmission stiffness is increased by 40% compared with the traditional structure.

[0039] The inner wall groove of the anti-rotation sleeve 7 is configured as a blind-blocking structure, which plays an important role in limiting movement. When the nut 5 retracts to the motor zero position at a constant speed, the blind-blocking structure can accurately limit the movement, with the limit tolerance configured to a zero position error ≤ ±0.1mm. Especially in the event of an unexpected power failure of the motor, the electric cylinder will rapidly depressurize, and the nut 5 will accelerate back to the motor zero position. At this time, the blind-blocking of the inner wall groove of the anti-rotation sleeve 7 can effectively prevent the nut 5 from directly hitting the bottom of the cylinder, avoiding functional failure of the motor and braking system, and completely solving the industry pain point of hitting the bottom of the cylinder.

[0040] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The terminology used in the description of this application is only for describing specific embodiments and is not intended to limit the exemplary embodiments according to this application. For ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings indicate similar items, and therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0041] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and are not limited in number; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0042] It should be noted that in the description of this application, the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

Claims

1. A ball screw anti-rotation mechanism based on involute guide rail pre-embedded in an involute guide, characterized in that, The device includes a valve block, which is connected to one end of an anti-rotation sleeve via fasteners. A nut is fitted into the anti-rotation sleeve. The nut has at least two grooves evenly spaced on its outer cylindrical surface. A square key is provided at the lower end of the involute guide rail, and the square key and the grooves are fitted together. The anti-rotation sleeve has involute grooves on its inner cylindrical surface, the number of which matches the number of involute guide rails. The involute grooves are fitted with the upper end of the involute guide rails with a clearance fit. The involute guide rails are used to prevent the nut from rotating. The nut and the lead screw are connected by threads.

2. The anti-rotation mechanism for a ball screw pair based on an involute guide rail pre-embedded according to claim 1, characterized in that, The groove is equipped with blind plug structures at both ends to prevent the involute guide rail from moving bidirectionally along the axial direction of the groove, thus serving as a limiting function.

3. The anti-rotation mechanism for a ball screw pair based on an involute guide rail pre-embedded according to claim 1, characterized in that, A tangential stepped surface is provided on the outer side of the groove, and the tangential stepped surface has a protruding part, which is used to fix the involute guide rail in the groove to complete the rigid connection.

4. The anti-rotation mechanism for a ball screw pair based on an involute guide rail pre-embedded according to claim 1, characterized in that, The inner wall of the nut is provided with an internal thread, which is tightly connected to the spiral raceway of the lead screw. The balls roll between the internal thread of the nut and the outer spiral raceway of the lead screw, so that the lead screw drives the nut to rotate through rolling friction, thereby realizing the transmission of power.

5. The anti-rotation mechanism for a ball screw pair based on an involute guide rail pre-embedded according to claim 1, characterized in that, The groove of the anti-rotation sleeve is set as a blind plug structure on the outside to limit the movement and prevent the nut from hitting the bottom of the cylinder.

6. The anti-rotation mechanism for a ball screw pair based on an involute guide rail pre-embedded according to claim 1, characterized in that, One end of the anti-rotation sleeve is equipped with evenly distributed petal-shaped flanges, which engage with the petal-shaped flange notches on the side of the valve block.

7. The anti-rotation mechanism for a ball screw pair based on an involute guide rail pre-embedded according to claim 1, characterized in that, The fastener is a rivet, and the outer diameter of the rivet is equipped with a rubber sleeve, and the two are fitted with a clearance fit.

8. The anti-rotation mechanism for a ball screw pair based on an involute guide rail pre-embedded according to claim 7, characterized in that, The rivets pass through the mounting holes of the anti-rotation sleeve and are then pressed into the blind holes of the valve block, thereby fixing the anti-rotation sleeve to the valve block.

9. The anti-rotation mechanism for a ball screw pair based on an involute guide rail pre-embedded according to claim 1, characterized in that, The involute guide rail and the groove of the anti-rotation sleeve are in involute-shaped surface contact, which is used to convert the rotational motion of the lead screw into the linear motion of the lead nut.

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