Dual-motor drive redundant ball screw pair

Abstract

The utility model discloses a double motor drive redundancy ball screw pair, including casing, thrust needle bearing, primary nut, screw, secondary nut, four point contact ball bearing and locking nut, the casing is connected with main drive motor through external spline, and the inner wall of casing is provided with internal spline and is matched with the transmission of external spline of primary nut, the thrust needle bearing is set up in the end of casing, and the screw is coaxially arranged in the inside of primary nut and secondary nut, and the steel ball is arranged between primary nut, secondary nut and screw, and the reverser constitutes ball screw pair, the secondary nut is connected with auxiliary drive motor through internal spline, and the locking nut is in screw thread cooperation with secondary nut, and the four point contact ball bearing is sleeved on the outside of secondary nut and is axially limited by locking nut, the utility model discloses two stage independent drive nut and realizes the drive redundancy, and when main drive fails, the auxiliary drive can take over the operation, avoids the system failure caused by screw jam, improves the operation safety, and the overall structure is compact, and is suitable for a variety of application scenarios.

Description

Technical Field

[0001] This utility model relates to the field of ball screw transmission technology, and in particular to a dual-motor driven redundant ball screw pair. Background Technology

[0002] With the development of automation and wire control technology, ball screw assemblies, as components for converting rotary motion into linear motion, are widely used in various transmission systems. Existing ball screw assemblies mostly employ a single drive source and a single set of nut and screw structures. If the drive motor fails during operation, or if jamming occurs between the nut and screw, the screw will immediately stop axial movement, directly causing the entire transmission system to fail. This makes it difficult to meet the high safety requirements of applications. Furthermore, the long-term wear and tear of the single raceway will directly shorten the overall service life of the product. Utility Model Content

[0003] To address the shortcomings of existing technologies, the purpose of this invention is to propose a dual-motor driven redundant ball screw pair. Through a two-stage independent drive nut structure arranged coaxially, it achieves drive redundancy backup and solves the problem of failure due to a single drive screw malfunction.

[0004] A dual-motor driven redundant ball screw assembly includes a housing, a thrust needle roller bearing, a primary nut, a screw, a secondary nut, a four-point contact ball bearing, and a lock nut. The outer circumferential surface of the housing is provided with external splines for transmission with the main drive motor. The inner wall of the housing is provided with internal splines, and the outer circumferential surface of the primary nut is provided with external splines; the internal splines of the housing and the external splines of the primary nut engage for transmission. The thrust needle roller bearing is located at the end of the housing to withstand axial force. The screw coaxially passes through the primary and secondary nuts, with a steel ball and a reversing mechanism forming a first ball screw assembly between the primary nut and the screw. A steel ball and a reversing mechanism form a second ball screw assembly between the secondary nut and the screw. One end of the inner hole of the secondary nut has an internal spline section for connection with the secondary drive motor. The inner ring of the four-point contact ball bearing is fitted onto the outer circumferential surface of the secondary nut, and the outer ring mates with the inner wall of the housing. The lock nut engages with the external thread of the secondary nut and axially abuts against the inner ring side face of the four-point contact ball bearing.

[0005] As a further improvement of this utility model, a pin is fixedly connected to the body of the lead screw, and the pin extends outward along the radial direction of the lead screw.

[0006] As a further improvement of this utility model, a sealing element is provided between the housing and the lead screw.

[0007] As a further improvement of this utility model, a slot is provided on the inner wall of the housing, and a retaining spring is installed in the slot, which abuts against the side end face of the four-point contact ball bearing.

[0008] By adopting the above technical solution, the following technical effects are achieved: Through a coaxial nested two-stage nut structure, two independent main and auxiliary drive sources are respectively connected, forming two independent ball screw transmission pairs on a single lead screw. During normal operation, the main drive side completes the axial drive of the lead screw. When the main drive motor fails or the first-stage nut jams with the lead screw, the auxiliary drive side can immediately take over to drive the lead screw to complete the axial movement, effectively avoiding direct failure of the transmission system due to a single point of failure, and significantly improving operational safety and reliability. The overall structure is coaxially integrated, compact in size, and adaptable to various application scenarios. Simultaneously, the two-stage transmission pairs can alternately bear loads, extending the product's service life to a certain extent. Seals prevent external impurities from entering the lead screw, avoiding grease leakage and ensuring the operational stability of the internal transmission structure. Pins restrict the lead screw's rotation, ensuring reliable conversion of rotary motion into linear motion. Snap rings combined with locking nuts provide bidirectional limit on the bearings, improving the stability of the support structure. Reversers form a steel ball circulation loop, ensuring smooth operation of the ball screw pair. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the overall assembly cross-sectional structure of this utility model; Figure 2 This is a schematic diagram of the overall structure of this utility model; Figure 3 This is a partial structural diagram of the present invention; Figure 4 for Figure 1 Enlarged view of point a in the middle.

[0010] 1. Housing; 2. Thrust needle roller bearing; 3. Primary nut; 4. Seal; 5. Lead screw; 6. Pin; 7. Secondary nut; 8. Snap ring; 9. Four-point contact ball bearing; 10. Locking nut. Detailed Implementation

[0011] Reference Figures 1 to 4 The embodiments of this utility model will be further described below.

[0012] This embodiment of the dual-motor driven redundant ball screw pair includes a housing 1, a thrust needle roller bearing 2, a primary nut 3, a screw 5, a secondary nut 7, a four-point contact ball bearing 9, and a locking nut 10. The housing 1 is connected to the main drive motor via an external spline, and an internal spline is provided on the inner wall of the housing 1 to engage with the external spline of the primary nut 3 for transmission. The thrust needle roller bearing 2 is located at the end of the housing 1 to bear axial force. The screw 5 is coaxially inserted inside the primary nut 3 and the secondary nut 7, and a steel ball and a reversing device are provided between the primary nut 3 and the screw 5 to form a first ball screw pair. The secondary nut 7 is connected to the secondary drive motor via an internal spline, and a steel ball and a reversing device are provided between the secondary nut 7 and the screw 5 to form a second ball screw pair. The inner ring of the four-point contact ball bearing 9 is fitted onto the outer circumferential surface of the secondary nut 7, and the outer ring engages with the inner wall of the housing 1. The locking nut 10 engages with the external thread of the secondary nut 7 and axially abuts against the inner ring side face of the four-point contact ball bearing 9.

[0013] Under normal operating conditions, the main drive motor outputs torque to rotate the housing 1. The housing 1, through a spline connection, drives the primary nut 3 to rotate synchronously. The primary nut 3, in conjunction with the lead screw 5, converts the rotational motion into the axial linear motion of the lead screw 5, completing the transmission action. At this time, the auxiliary drive motor drives the secondary nut 7 to rotate synchronously, without outputting drive torque. The leads of the two sets of helical pairs are consistent, and the secondary nut 7 has no axial displacement relative to the lead screw 5. When the main drive motor fails, or when there is jamming between the primary nut 3 and the lead screw 5, the main drive side stops operating. The auxiliary drive motor then outputs torque, driving the secondary nut 7 to rotate. The secondary nut 7 then drives the lead screw 5 to continue completing the axial displacement. This avoids the transmission system stopping directly due to a single point of failure, solving the problem of failure upon failure of the traditional single-drive lead screw, ensuring continuous transmission action, and improving the safety and reliability of the system.

[0014] Furthermore, a pin 6 is fixedly connected to the body of the lead screw 5, and the pin 6 extends radially outward along the lead screw 5. The pin 6 can cooperate with an external frame or a limiting structure to restrict the circumferential rotation of the lead screw 5 itself, ensuring that the rotational motion of the nut can be stably converted into the axial linear motion of the lead screw 5, preventing the lead screw 5 from spinning freely with the nut, ensuring transmission efficiency and accuracy, and helping to improve the operational stability during the switching process of redundant drives.

[0015] Furthermore, a seal 4 is provided between the housing 1 and the lead screw 5. The seal 4 can fill the assembly gap between the housing and the lead screw 5, prevent external dust and impurities from entering the raceway area inside the lead screw, and at the same time prevent internal grease from leaking outward, maintain the lubrication state of the internal transmission structure, reduce the risk of jamming, and extend the maintenance cycle and service life of the product.

[0016] Furthermore, a retaining groove is provided on the inner wall of the housing 1, and a retaining spring 8 is installed in the retaining groove. The retaining spring 8 abuts against the side end face of the four-point contact ball bearing 9. The retaining spring 8, together with the locking nut 10, forms an axial limit on the four-point contact ball bearing 9 from both sides, preventing the bearing from moving under axial load, improving the stability of the support structure, ensuring the rotational accuracy of the secondary nut 7, and at the same time assisting in bearing the axial load, preventing the axial force from being transmitted to the auxiliary drive motor.

[0017] Both the primary nut 3 and the secondary nut 7 are equipped with a reverser. The reverser, in conjunction with the raceway of the corresponding nut, forms a circulation loop for the steel balls. The reverser is a known component in the prior art. It guides the steel balls to continuously circulate within the raceway, ensuring smooth transmission of the ball screw pair, reducing frictional resistance, improving transmission efficiency, and simultaneously reducing abnormal wear between the steel balls and the raceway, thus helping to extend the service life of the lead screw.

[0018] In summary, this solution adopts a coaxial nested double-nut structure, which is connected to independent main and auxiliary drive motors respectively. Two independent ball screw transmission systems are built on a single lead screw. By operating in a mode where the main drive is running normally and the auxiliary drive is redundantly backed up, the problem of direct failure of traditional single-drive ball screws due to motor failure or nut jamming is solved, thus improving the safety and reliability of the transmission system. At the same time, the overall structure is compact and highly integrated, adaptable to various application scenarios, and has a longer service life.

[0019] The above description is merely a preferred embodiment of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are protected. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within the protection scope of this utility model.

Claims

1. A dual-motor drive redundant ball screw pair, characterized by: The system includes a housing, a thrust needle roller bearing, a primary nut, a lead screw, a secondary nut, a four-point contact ball bearing, and a lock nut. The outer circumferential surface of the housing has external splines for transmission with the main drive motor. The inner wall of the housing has internal splines, and the outer circumferential surface of the primary nut has external splines; the internal splines of the housing and the external splines of the primary nut engage for transmission. The thrust needle roller bearing is located at the end of the housing to withstand axial force. The lead screw coaxially passes through the primary and secondary nuts, with a steel ball and a reversing mechanism forming a first ball screw pair between the primary nut and the lead screw. A steel ball and a reversing mechanism form a second ball screw pair between the secondary nut and the lead screw. One end of the inner hole of the secondary nut has an internal spline section for connection with the secondary drive motor. The inner ring of the four-point contact ball bearing is fitted onto the outer circumferential surface of the secondary nut, and the outer ring mates with the inner wall of the housing. The lock nut engages with the external thread of the secondary nut and axially abuts against the inner ring side face of the four-point contact ball bearing.

2. Dual-motor drive redundant ball screw pair according to claim 1, characterized in that: A pin is fixedly connected to the body of the lead screw, and the pin extends outward along the radial direction of the lead screw.

3. The dual-motor drive redundant ball screw pair of claim 1, wherein: A seal is provided between the housing and the lead screw.

4. The dual-motor drive redundant ball screw pair of claim 1, wherein: The inner wall of the housing is provided with a retaining groove, and a retaining spring is installed in the retaining groove. The retaining spring abuts against the side end face of the four-point contact ball bearing.

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