Double-layer ball screw pair and aircraft

Abstract

The invention discloses a double-layer ball screw pair and an aircraft. The double-layer ball screw pair comprises a first-stage nut, a first-stage ball screw, a second-stage nut, a second-stage ball screw, a limiting buffer device, a first-stage safety rod and a second-stage safety rod. When the first-stage nut rotates, the first-stage ball screw can be driven to do linear motion. And when the first-stage ball screw linearly moves to the limiting position and further moves, the first-stage ball screw is locked with the first-stage nut through the limiting buffer device, so that the first-stage nut drives the first-stage ball screw to synchronously rotate when rotating. When the first-stage ball screw rotates, the second-stage nut rotates synchronously to drive the second-stage ball screw to do linear motion. When any stage of ball screw pair fails, the other stage of ball screw pair can work normally, and the practicability of the ball screw pair is improved under double-layer guarantee.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of precision transmission, and particularly relates to a double-layer ball screw pair and an aircraft. BACKGROUND

[0002] Ball screw pairs are widely used in aircraft and are one of the core important components for the aircraft wings to complete tilting and tilting actions. At present, with the development of miniaturization and light weight of aircraft, more stringent requirements are put forward for the weight and volume of ball screw pairs.

[0003] In order to reduce the volume and weight of the ball screw pair while taking into account the stroke, multiple ball screw pairs are often used in aircraft, but once any stage fails, the entire ball screw pair will completely fail, greatly affecting the practicability of the ball screw pair. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a double-layer ball screw pair to solve the above problems in the prior art.

[0005] The first nut is connected with the first ball screw to form a first ball screw pair, the first ball screw has an axial hollow channel inside, the second nut is arranged in the hollow channel and is integrally connected with the first ball screw, the second ball screw is connected with the second nut to form a second ball screw pair which is sleeved inside the first ball screw pair, and two sets of outer limiting and buffering devices are arranged at the axial two ends of the first ball screw, and two sets of inner limiting and buffering devices are arranged at the axial two ends of the second ball screw. The first safety rod is connected with the first ball screw through a bearing, and is used to replace the first ball screw to operate when the first ball screw fails.

[0006] The second safety rod is connected with the second ball screw through a bearing, and is used to replace the second ball screw to operate when the second ball screw fails.

[0007] When the first nut rotates, it drives the first ball screw to move linearly.

[0008] When the first ball screw moves linearly to the limit position and further moves, the first ball screw is locked with the first nut through a set of outer limiting and buffering devices, so that the first nut drives the first ball screw to rotate synchronously when the first nut rotates. When the first ball screw rotates, the second nut rotates synchronously and drives the second ball screw to move linearly in the same direction until it is locked under the action of a set of inner limiting and buffering devices.

[0009] In a possible implementation, each set of outer layer limiting and buffering device is clamped between the outer threaded end of one end of the primary ball screw and the primary safety rod, and each set of inner layer limiting and buffering device is clamped between the outer threaded end of one end of the secondary ball screw and the primary safety rod; each set of outer layer limiting and buffering device at least includes a first annular spring, a first pressing plate and a first thrust bearing, each set of inner layer limiting and buffering device at least includes a second annular spring, a second pressing plate and a second thrust bearing, the first annular spring is clamped between one first pressing plate and the first thrust bearing, and the second annular spring is clamped between one second pressing plate and the second thrust bearing; when the primary ball screw moves linearly to the limit position and further moves, the axial force generated by the movement of the primary nut is transmitted to the first annular spring by extruding the first pressing plate, the first annular spring generates a friction force by conical surface friction to realize buffering, when the friction force and the axial force are balanced, the primary ball screw is locked with the primary nut through the outer layer limiting and buffering device, so that the primary nut drives the primary ball screw to rotate synchronously when the primary nut rotates; when the primary ball screw rotates, the secondary nut rotates synchronously, driving the secondary ball screw to move linearly in the same direction, the axial force generated by the movement of the secondary ball screw is transmitted to the second annular spring by extruding the second pressing plate, the second annular spring generates a friction force by conical surface friction to realize buffering, when the friction force and the axial force are balanced, the secondary ball screw is locked with the secondary nut through the inner layer limiting and buffering device.

[0010] In a possible implementation, each set of outer layer limiting and buffering device further includes an annular pressing sleeve, and the annular pressing sleeve is buckled on the outside of the first annular spring.

[0011] In a possible implementation, the two ends of the primary ball screw pair and the two ends of the secondary ball screw pair are provided with dustproof rings.

[0012] In a possible implementation, the two ends of the primary ball screw pair and the two ends of the secondary ball screw pair are provided with ice removing rings.

[0013] The application further provides an aircraft, which comprises any of the double-layer ball screw pairs described above.

[0014] In a possible implementation, the double-layer ball screw pair further has a circulating oiling structure, the circulating oiling structure penetrates the primary nut and the secondary nut vertically along the axial direction of the double-layer ball screw pair, and the lubricating grease can be circulated and discharged along the nut raceways of the primary nut and the secondary nut. In the oiling process, the aged lubricating grease and the debris generated by metal wear are completely excluded, the reliability and the service life of the double-layer ball screw pair can be effectively improved, the disassembly and maintenance capability is provided, the frequency of off-machine maintenance is reduced, and the maintenance cost is reduced.

[0015] The double-layer ball screw assembly disclosed in this invention includes: a primary nut, a primary ball screw, a secondary nut, a secondary ball screw, a limiting buffer device, a primary safety rod, and a secondary safety rod. The primary nut and the primary ball screw are connected to form a primary ball screw assembly. The primary ball screw has an axial hollow channel inside. The secondary nut is disposed within the hollow channel and integrally connected to the primary ball screw. The secondary ball screw and the secondary nut are connected to form a secondary ball screw assembly sleeved inside the primary ball screw assembly. The buffer device is disposed at the axial end of the primary ball screw. The primary safety rod is connected to the primary ball screw via a first self-made bearing, and the secondary safety rod is connected to the secondary ball screw via a second self-made bearing. When the primary nut rotates, it can drive the primary ball screw to perform linear motion. When the primary ball screw reaches its limit position and moves further, the primary ball screw is locked to the primary nut by the limiting buffer device, so that the primary nut drives the primary ball screw to rotate synchronously when rotating. When the primary ball screw rotates, the secondary nut rotates synchronously, driving the secondary ball screw to perform linear motion. In this invention, under the action of the primary and secondary safety rods, if either primary ball screw pair fails, the other primary ball screw pair can still function normally. That is, if either primary fails, at least 50% of the stroke can be guaranteed, thus improving the practicality of the ball screw pair through this double-layer protection.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a double-layer ball screw assembly according to the present invention; Figure 2 This is one of the cross-sectional schematic diagrams of a double-layer ball screw pair according to the present invention; Figure 3 This is a second schematic cross-sectional view of a double-layer ball screw pair according to the present invention.

[0018] Explanation of reference numerals in the attached figures: Detailed Implementation

[0019] like Figure 1 , Figure 2 As shown, the double-layer ball screw assembly may include: a primary nut 01, a primary ball screw 02, a secondary nut 03, a secondary ball screw 04, two sets of outer limiting buffer devices 05, two sets of inner limiting buffer devices 06, a primary safety bar 07, and a secondary safety bar 08.

[0020] The primary nut 01 is connected with the primary ball screw 02 to form a primary ball screw pair, the primary ball screw has an axial hollow channel inside, the secondary nut 03 is arranged in the hollow channel and is integrally connected with the primary ball screw 02, the secondary ball screw 04 is connected with the secondary nut 03 to form a secondary ball screw pair which is sleeved in the primary ball screw pair, and two sets of outer layer limiting and buffering devices 05 are respectively arranged at the axial two ends of the primary ball screw 02, and two sets of inner layer limiting and buffering devices 06 are respectively arranged at the axial two ends of the secondary ball screw 04.

[0021] The primary safety rod 07 is connected with the primary ball screw 02 through a bearing, and the primary safety rod 07 is used to replace the primary ball screw 02 to operate when the primary ball screw 02 fails. The secondary safety rod 08 is connected with the secondary ball screw 04 through a bearing, and the secondary safety rod 08 is used to replace the secondary ball screw 04 to operate when the secondary ball screw 04 fails.

[0022] When the double-layer ball screw pair is stretched outwards, the primary nut 01 rotates to drive the primary ball screw 02 to move linearly and stretch outwards, when the primary ball screw 02 moves linearly to the limit position and further moves, the primary ball screw 02 is locked with the primary nut 01 through one set of outer layer limiting and buffering devices 05, so that the primary nut 01 can drive the primary ball screw 02 to rotate synchronously when rotating, the secondary nut 03 rotates synchronously when the primary ball screw 02 rotates, drives the secondary ball screw 04 to move linearly in the same direction and continue to stretch outwards, and is locked under the action of one set of inner layer limiting and buffering devices 06.

[0023] Further, when the double-layer ball screw pair is retracted inwards, the primary nut 01 reversely rotates to drive the primary ball screw 02 to move linearly in the reverse direction and retract inwards, when the primary ball screw 02 moves linearly to the limit position and further moves, the primary ball screw 02 is locked with the primary nut 01 through the other set of outer layer limiting and buffering devices 05, so that the primary nut 01 can drive the primary ball screw 02 to reversely rotate synchronously when rotating, the secondary nut 03 reversely rotates synchronously when the primary ball screw 02 reversely rotates, drives the secondary ball screw 04 to move linearly in the reverse direction and continue to retract inwards, and is locked under the action of the other set of inner layer limiting and buffering devices 06.

[0024] When any primary ball screw pair appears to be stuck, the ball screw pair cannot move linearly, but only rotates, the stuck ball screw pair drives the other nut to rotate, and the other ball screw normally moves linearly, so that at least 50% of the effective stroke can be ensured when any primary ball screw pair fails.

[0025] In this embodiment, under the action of the primary safety rod 07 and the secondary safety rod 08, when one of the primary ball screw pairs fails, the other primary ball screw pair can work normally, that is, at least 50% of the stroke can be ensured when one of the primary ball screw pairs fails, and the practicability of the ball screw pair is improved under the double-layer protection.

[0026] Optionally, as shown in Figure 2 Each set of outer layer limiting and buffering device 05 is clamped between the outer thread end of one end of the primary ball screw 02 and the primary safety rod 07, and each set of inner layer limiting and buffering device 06 is clamped between the outer thread end of one end of the secondary ball screw 04 and the primary safety rod 07.

[0027] Each set of outer layer limiting and buffering device 05 at least includes a first annular spring 51, a first pressing plate 52 and a first thrust bearing 53, and each set of inner layer limiting and buffering device 06 at least includes a second annular spring 61, a second pressing plate 62 and a second thrust bearing 63. The first annular spring 51 is clamped between one first pressing plate 52 and the first thrust bearing 53, and the second annular spring 61 is clamped between one second pressing plate 62 and the second thrust bearing 63.

[0028] When the double-layer ball screw pair extends outward, the primary ball screw 02 moves linearly to extend to the limit position and further moves, the axial force generated by the movement of the primary nut 01 is transmitted to the first annular spring 51 by extruding the first pressing plate 52, the first annular spring 51 realizes buffering through the friction force generated by the conical friction, and when the friction force and the axial force are balanced, the primary ball screw 02 is locked with the primary nut 01 through the outer layer limiting and buffering device 05, so that the primary nut 01 rotates to drive the primary ball screw 02 to rotate synchronously.

[0029] Further, when the primary ball screw 02 rotates, the secondary nut 03 rotates synchronously to drive the secondary ball screw 04 to move linearly in the same direction, the axial force generated by the movement of the secondary ball screw 04 is transmitted to the second annular spring 61 by extruding the second pressing plate 62, the second annular spring 61 realizes buffering through the friction force generated by the conical friction, and when the friction force and the axial force are balanced, the secondary ball screw 04 is locked with the secondary nut 03 through the inner layer limiting and buffering device 06.

[0030] It can be understood that in addition to the elastic structure design, the outer layer limiting and buffering device 05 and the inner layer limiting and buffering device 06 can also be a hard locking and stopping structure.

[0031] Specifically, taking the hard locking stop structure of the outer layer limiting and buffering device 05 as an example, one end of the locking stop structure is abutted against the outer thread end of the first ball screw 02, and the other end is abutted against the end of the first safety rod 07. When the first ball screw 02 linearly moves outward to the limit position and further moves, the first nut 01 is locked by cooperating with the locking stop structure, so that the first nut 01 drives the first ball screw 02 to rotate synchronously when rotating. The working principle of the inner layer limiting and buffering device 05 is the same as above, and will not be repeated here.

[0032] In the embodiment, the outer layer limiting and buffering device 05 and the inner layer limiting and buffering device 06 are both elastic structures, and the taper friction of the annular spring is used to realize buffering, so that the impact resistance and durability of the double-layer ball screw pair are effectively improved.

[0033] Optionally, as shown in Figure 2 , each set of outer layer limiting and buffering device can further include an annular pressing sleeve 54, and the annular pressing sleeve 54 is buckled on the outside of the first annular spring 51 to play a limiting and protecting role.

[0034] Optionally, as shown in Figure 2 , the two ends of the first ball screw pair and the two ends of the second ball screw pair are both provided with dustproof rings 09. In the movement process, the dustproof rings 09 can prevent dust from entering the exposed screw rod surface raceway, eliminate the influence of dust on the transmission efficiency and capacity, and effectively improve the working efficiency and reliability of the screw rod.

[0035] Optionally, as shown in Figure 2 , the two ends of the first ball screw pair and the two ends of the second ball screw pair are both provided with ice removing rings 10. In the movement process, the ice removing rings 10 can quickly remove ice from the exposed screw rod surface raceway by rotating, eliminate the influence of ice on the transmission efficiency and capacity of the screw rod, and effectively improve the low-temperature working efficiency and reliability of the screw rod.

[0036] Optionally, as shown in Figure 3 , the double-layer ball screw pair further has a circulating oiling structure 11, and the circulating oiling structure 11 penetrates the first nut and the second nut from the outside in the axial direction of the double-layer ball screw pair. The lubricating grease can be discharged from the circulating oiling structure 11 along the nut raceway of the first nut and the second nut. In the oiling process, the aged lubricating grease and the debris generated by metal wear are completely removed, the reliability and service life of the double-layer ball screw pair are effectively improved, the disassembly and maintenance capacity is provided, the frequency of off-machine maintenance is reduced, and the maintenance cost is reduced.

[0037] The application also provides a flying vehicle, and the flying vehicle includes the double-layer ball screw pair in any of the above embodiments.

[0038] The above is only the preferred embodiment of the present application, and does not limit the present application, and any simple modification, change and equivalent structure change of the above embodiment according to the technical essence of the present application are still within the protection scope of the technical scheme of the present application.

Claims

1. A double-layer ball screw assembly, characterized in that, include: Primary nut, primary ball screw, secondary nut, secondary ball screw, two sets of outer limiting buffer devices, two sets of inner limiting buffer devices, primary safety bar and secondary safety bar; The primary nut is connected to the primary ball screw to form a primary ball screw pair. The primary ball screw has an axial hollow channel inside. The secondary nut is disposed in the hollow channel and is integrally connected to the primary ball screw. The secondary ball screw and the secondary nut are connected to form a secondary ball screw pair sleeved inside the primary ball screw pair. Two sets of outer limiting buffer devices are respectively disposed at both ends of the axial direction of the primary ball screw, and two sets of inner limiting buffer devices are respectively disposed at both ends of the axial direction of the secondary ball screw. The first-stage safety lever is connected to the first-stage ball screw via a bearing. The first-stage safety lever is used to replace the first-stage ball screw in the event of failure. The secondary safety lever is connected to the secondary ball screw via a bearing. The secondary safety lever is used to replace the operation of the secondary ball screw when the secondary ball screw fails. When the primary nut rotates, it drives the primary ball screw to perform linear motion; When the first-stage ball screw moves linearly to its limit position and moves further, the first-stage ball screw is locked to the first-stage nut by a set of outer limiting buffer devices, so that when the first-stage nut rotates, it drives the first-stage ball screw to rotate synchronously. When the primary ball screw rotates, the secondary nut rotates synchronously, driving the secondary ball screw to move in the same direction until it is locked by an inner limiting and buffering device.

2. The double-layer ball screw assembly according to claim 1, characterized in that, Each set of the outer limiting buffer device is clamped between the external thread end of one end of the first-stage ball screw and the first-stage safety rod, and each set of the inner limiting buffer device is clamped between the external thread end of one end of the second-stage ball screw and the first-stage safety rod. Each set of the outer limiting buffer device includes at least a first ring spring, a first pressure plate and a first thrust bearing, and each set of the inner limiting buffer device includes at least a second ring spring, a second pressure plate and a second thrust bearing. The first ring spring is sandwiched between a first pressure plate and a first thrust bearing, and the second ring spring is sandwiched between a second pressure plate and a second thrust bearing. When the first-stage ball screw moves linearly to its limit position and moves further, the axial force generated by the movement of the first-stage nut is transmitted to the first annular spring by squeezing the first pressure plate. The first annular spring is buffered by the friction generated by the conical surface friction. When the friction force is balanced with the axial force, the first-stage ball screw is locked to the first-stage nut by the outer limiting buffer device, so that when the first-stage nut rotates, it drives the first-stage ball screw to rotate synchronously. When the primary ball screw rotates, the secondary nut rotates synchronously, driving the secondary ball screw to make linear motion in the same direction. The axial force generated by the movement of the secondary ball screw is transmitted to the second annular spring by pressing the second pressure plate. The second annular spring achieves buffering through the friction force generated by the conical surface friction. When the friction force is balanced with the axial force, the secondary ball screw is locked to the secondary nut by the inner limiting buffer device.

3. The double-layer ball screw assembly according to claim 2, characterized in that, Each set of the outer limiting buffer device also includes an annular pressure sleeve, which is pressed against the outside of the first annular spring.

4. The double-layer ball screw assembly according to any one of claims 1-3, characterized in that, Dustproof rings are provided at both ends of the primary ball screw assembly and at both ends of the secondary ball screw assembly.

5. The double-layer ball screw assembly according to any one of claims 1-3, characterized in that, De-icing rings are provided at both ends of the primary ball screw pair and both ends of the secondary ball screw pair.

6. An aircraft, characterized in that, The aircraft includes a double-layer ball screw pair as described in any one of claims 1-5.

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