Leading screw shifting fork anti-rotation guide mechanism capable of resisting lateral load

Abstract

A lead screw shifting fork anti-rotation guide mechanism capable of resisting lateral load comprises a shell, a shifting fork shaft, a lead screw, a lead screw nut, a roller pin and a bearing. The shifting fork shaft is installed in the shell, the lead screw and the lead screw nut form a lead screw pair, the lead screw pair is also installed in the shell through a bearing, and the axis of the lead screw is perpendicular to the axis of the plugging shaft; two pin shafts on the lead screw nut are arranged in two U-shaped grooves in the side face of the shifting fork shaft, and a plurality of roller pins are evenly distributed on the side face of the lead screw nut in parallel. The axis direction of the roller pin is parallel to the axis of the shifting fork shaft, the lead screw is arranged between the roller pin and the shifting fork shaft, and the roller pin is in contact fit with the side face of the lead screw nut and the inner plane of the shell at the same time. During working, lateral force generated by transmission of the lead screw shifting fork can be transmitted to the shell, so that the lead screw pair only bears axial force, and the transmission efficiency is improved. In addition, the lead screw pair does not bear lateral force any more, so that a large-specification lead screw does not need to be selected to cope with the lateral force during design, and miniaturization and lightweight design is facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to a screw yoke anti-rotation guide mechanism, in particular to a screw yoke anti-rotation guide mechanism with anti-lateral load, belonging to the field of aerospace equipment. BACKGROUND

[0002] The screw yoke transmission mechanism is widely used in small rudders due to its compact structure and large reduction ratio. When the screw of the screw yoke transmission mechanism is extended or retracted to the limit position, the load on the yoke shaft will be transmitted to the screw pair through the yoke, so that the screw nut bears a lateral load perpendicular to the direction of motion. When the deflection angle of the yoke shaft increases, the load it bears will also increase, thereby increasing the lateral load on the screw nut. The lateral load is a harmful force for the normal operation of the screw pair, affecting the transmission efficiency and service life of the screw pair. When the lateral load is too large, it may also cause the screw pair to jam.

[0003] Most of the prior art uses guide blocks, guide grooves, and yoke rods to ensure that the screw yoke transmission mechanism can work normally under heavy load. However, these settings do not enable the transmission mechanism to have the ability to resist lateral loads, and do not solve the problem that the lateral force on the screw pair under heavy load may cause the transmission mechanism to jam. In actual engineering, although a larger screw can be used to bear the lateral force, this is not conducive to the miniaturization and lightweight design of the screw yoke transmission mechanism.

[0004] For example: a new large power level electromechanical actuator guide device is disclosed in patent CN106015487A. The actuator is provided with guide blocks and guide grooves to overcome the screw rotation torque and achieve the guiding function under heavy load, but it does not have the function of resisting lateral loads.

[0005] A high-rigidity anti-rotation guide device for a ball screw is disclosed in patent CN107061657A. A yoke rod is provided on the screw nut, and the yoke rod slides in the guide groove to achieve the guiding function. However, it also does not have the function of resisting lateral loads.

[0006] An execution mechanism of a large-load anti-jamming electric rudder is disclosed in patent CN110953313B. A transmission pin is provided on the screw nut, and a bushing is provided on the transmission pin to increase the force bearing area of the yoke and the transmission pin, thereby increasing the carrying capacity of the transmission pin and solving the problem of jamming caused by wear of the transmission pin. However, it does not solve the problem of jamming caused by the lateral force on the screw pair under heavy load. SUMMARY

[0007] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a screw yoke anti-rotation guide mechanism with anti-lateral load. The mechanism eliminates the lateral load on the screw pair, improves the transmission efficiency, and is convenient for miniaturization design.

[0008] The technical solution of the present application is:

[0009] A kind of anti-lateral load's lead screw yoke anti-rotation guide mechanism, including shell, yoke shaft, lead screw, lead screw nut, needle and bearing;

[0010] Yoke shaft is installed in the inside of shell, lead screw and lead screw nut form lead screw pair, also be installed in the inside of shell by bearing, and the axis of lead screw is perpendicular to the axis of yoke shaft;The section shape of lead screw nut is D type, arc surface faces yoke shaft, plane is away from yoke shaft, towards shell;Two pin shafts are further provided on lead screw nut, are placed in the two U-shaped grooves of yoke shaft side;Multiple needle is parallel and evenly distributed on the plane of lead screw nut, the axis of needle is parallel to the axis of yoke shaft, is spatially perpendicular to the axis of lead screw, needle is simultaneously contacted with the plane of lead screw nut and the inner plane of shell.

[0011] When working, lead screw rotates, drives lead screw nut linear motion, two pin shafts on lead screw nut drive yoke shaft to rotate, needle rolls between the plane side of lead screw nut and the inner plane of shell, to realize the anti-rotation guide function of lead screw nut, simultaneously, the lateral force generated by yoke shaft to lead screw nut is directly transmitted to shell.

[0012] Further, the plane side of lead screw nut is rectangular needle installation groove, for installing needle.

[0013] Further, the inner wall of needle installation groove is evenly arranged with needle limiting grid at both ends, each needle is separated by limiting grid, to ensure that needle does not affect each other in the movement process.

[0014] Further, the depth of needle installation groove provided by lead screw nut is 3 / 4-4 / 5 of the diameter of needle.

[0015] Further, the position of two pin shafts provided by lead screw nut is close to the end of lead screw nut plane, to increase the eccentric amount of pin shaft relative to the axis position of lead screw nut and the transmission arm length of yoke shaft in limited space, to further increase the reduction ratio of transmission, and facilitate the torque load generated by increasing eccentric amount to be directly transmitted to shell by needle.

[0016] Further, the plane of shell cooperating with needle is parallel to the plane of lead screw nut.

[0017] Further, the plane of shell cooperating with needle is hardened.

[0018] Further, a flat plate with surface hardness not less than 50HRC is embedded between shell and needle.

[0019] Further, the needle and the shell need to be lubricated during the contact fitting process, including: evenly applying lubricating grease to the surface of the needle, spraying molybdenum disulfide, or embedding solid lubricating particles on the fitting plane of the needle and the shell.

[0020] The beneficial effects of the present application compared with the prior art are:

[0021] (1) The present application sets a needle between the screw nut and the shell, so that the lateral force generated by the screw yoke transmission is transmitted to the shell, so that the screw pair no longer bears the lateral force, increases the transmission efficiency, improves the transmission reliability, and prolongs the service life of the mechanism.

[0022] (2) The present application can make the screw rod of the screw pair no longer bear the lateral force, and only need to consider the axial force when designing, without selecting a thicker screw to cope with the lateral force, which is convenient for miniaturization and lightweight design.

[0023] (3) The present application sets the two pin shafts of the screw nut on one side close to the plane of the screw nut, which can increase the eccentricity of the pin shaft of the screw nut, and is more conducive to directly transmitting the lateral force to the shell. The mechanism can increase the reduction ratio by 10% to 20% without changing the occupied space.

[0024] (4) The present application reduces the friction between the needle and the needle installation groove during the movement of the needle by digging the entire rectangular needle installation groove and setting the needle limiting grid, and further reduces the mass of the mechanism. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a cross-sectional view of the anti-lateral load screw yoke anti-rotation guide mechanism of the present application.

[0026] Figure 2 It is a schematic view of part of the anti-rotation guide mechanism of the screw yoke of the present application.

[0027] Figure 3 It is a schematic view of the needle structure of the screw nut of the anti-rotation guide mechanism of the screw yoke of the present application. DETAILED DESCRIPTION

[0028] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0029] As shown in Figure 1 , 2 and 3, the present application proposes an anti-lateral load screw yoke anti-rotation guide mechanism, which comprises a shell 1, a yoke shaft 2, a screw 3, a screw nut 4, a needle 5, and a bearing 6.

[0030] The fork shaft 2 is installed inside the housing 1, the lead screw 3 and the lead screw nut 4 form a lead screw pair, the bearing 6 is also installed inside the housing 1, and the axis of the lead screw 3 is perpendicular to the axis of the fork shaft 2; the cross section of the lead screw nut 4 is D-shaped, the circular arc surface faces the fork shaft 2, and the plane faces away from the fork shaft 2 and faces the housing 1; the lead screw nut 4 is also provided with two pin shafts arranged in the two U-shaped grooves on the side of the fork shaft 2; a plurality of needle rollers 5 are parallel and uniformly distributed on the plane of the lead screw nut 4, the axis of the needle roller 5 is parallel to the axis of the fork shaft 2, and the axis of the lead screw 3 is perpendicular to the axis of the lead screw 3, and the needle roller 5 is in contact with the plane of the lead screw nut 4 and the inner plane of the housing 1.

[0031] The whole mechanism is the internal transmission part of the steering engine, reducer and other equipment. When working, the steering engine, reducer and other equipment will drive the lead screw 3 to rotate, so that the lead screw nut 4 moves linearly; the two pin shafts on the lead screw nut 4 further drive the fork shaft 2 to rotate, and the needle roller 5 rolls between the plane side of the lead screw nut 4 and the inner plane of the housing 1, so as to realize the anti-rotation guiding function of the lead screw nut 4, and the lateral force generated by the fork shaft 2 on the lead screw nut 4 is directly transmitted to the housing. The above design makes the lead screw pair not bear the lateral force, increases the transmission efficiency, improves the transmission reliability, prolongs the service life of the mechanism. In addition, when designing the whole mechanism, it is not necessary to select a thicker lead screw to cope with the lateral force, which is convenient for miniaturization and lightweight design.

[0032] As shown in Figure 3 The plane side of the lead screw nut 4 has the following two design schemes:

[0033] Scheme one: the plane side of the lead screw nut 4 is provided with a plurality of parallel and uniformly distributed needle roller mounting grooves, and each needle roller mounting groove is arranged with a needle roller 5;

[0034] Scheme two: the plane side of the lead screw nut 4 is provided with a large rectangular needle roller mounting groove, and the inner wall of the needle roller mounting groove is uniformly arranged with needle roller limiting grids, the needle rollers 5 are separated by the limiting grids, and the movement of the needle rollers 5 is not affected.

[0035] The present application selects scheme two, which reduces the friction between the needle roller and the needle roller mounting groove during the movement of the needle roller, and further reduces the quality of the mechanism, which is convenient for lightweight design.

[0036] The specific number, material properties and specifications of the needle roller are selected according to the actual load.

[0037] Further, the depth of the needle roller mounting groove is 3 / 4-4 / 5 of the diameter of the needle roller 5.

[0038] The two pin shafts of the screw nut 4 are arranged near the end of the screw nut 4, so as to increase the eccentricity of the pin shafts of the screw nut 4 relative to the axis and the length of the transmission arm of the shift lever shaft in the limited space, and further increase the transmission reduction ratio, and facilitate the transmission of the torque load generated by the increased eccentricity to the housing 1 through the needle 5. The above design can increase the transmission reduction ratio by 10%-20% without changing the space occupied by the mechanism.

[0039] The inner plane of the housing 1 matched with the needle 5 is parallel to the plane of the screw nut 4, so as to ensure smooth operation of the needle 5 and stable load bearing.

[0040] The inner plane of the housing 1 matched with the needle 5 needs to be hardened, and the inner plane is arranged as a flat plate with high surface hardness, and the hardness is not less than 50HRC.

[0041] The surface of the needle 5 needs to be uniformly smeared with lubricating grease or sprayed with molybdenum disulfide for lubrication, and the housing 1 matched plane can also be inlaid with solid lubricating particles such as molybdenum disulfide.

[0042] The part not described in detail in the present application is common knowledge for those skilled in the art.

Claims

1. A lead screw fork anti-rotation guide mechanism for resisting lateral loads, characterized in that... include: Housing (1), shift fork shaft (2), lead screw (3), lead screw nut (4), needle roller (5), and bearing (6); The shift fork shaft (2) is installed inside the housing (1). The lead screw (3) and the lead screw nut (4) form a lead screw pair, which is also installed inside the housing (1) through the bearing (6). The axis of the lead screw (3) is perpendicular to the axis of the shift fork shaft (2). The cross-sectional shape of the lead screw nut (4) is D-shaped, with the arc surface facing the shift fork shaft (2) and the plane facing away from the shift fork shaft (2) and towards the housing (1). The lead screw nut (4) is also provided with two pins, which are placed in two U-shaped grooves on the side of the shift fork shaft (2). Multiple needle rollers (5) are parallel and evenly distributed on the plane of the lead screw nut (4). The axis of the needle rollers (5) is parallel to the axis of the shift fork shaft (2) and spatially perpendicular to the axis of the lead screw (3). The needle rollers (5) simultaneously contact and cooperate with the plane of the lead screw nut (4) and the inner plane of the housing (1).

2. The anti-rotation guide mechanism for a lead screw fork against lateral loads according to claim 1, characterized in that: When working, the lead screw (3) rotates, which drives the lead screw nut (4) to move linearly. The two pins on the lead screw nut (4) drive the shift fork shaft (2) to rotate. The needle roller (5) rolls between the side raceway of the lead screw nut (4) and the inner plane of the housing (1), thereby realizing the anti-rotation guiding function of the lead screw nut (4). At the same time, the lateral force generated by the shift fork shaft (2) on the lead screw nut (4) is directly transmitted to the housing.

3. The anti-rotation guide mechanism for a lead screw fork resisting lateral load according to claim 2, characterized in that: The ball screw nut (4) has a rectangular needle roller mounting groove on its planar side for mounting needle rollers (5).

4. The anti-rotation guide mechanism for a lead screw fork against lateral loads according to claim 3, characterized in that: Needle roller limit blocks are evenly arranged at both ends of the inner wall of the needle roller mounting groove. The limit blocks are used to separate each needle roller (5) to ensure that the needle rollers (5) do not affect each other during the movement.

5. A lateral load-resistant lead screw fork anti-rotation guide mechanism according to claim 3 or 4, characterized in that: The depth of the needle roller mounting groove on the lead screw nut (4) is 3 / 4 to 4 / 5 of the diameter of the needle roller (5).

6. A lateral load-resistant lead screw fork anti-rotation guide mechanism according to any one of claims 1-4, characterized in that: The two pins of the lead screw nut (4) are located close to one end of the plane of the lead screw nut (4), thereby increasing the eccentricity of the pins of the lead screw nut (4) relative to the axis and the length of the transmission arm of the shift fork shaft (2) in the limited space, thereby increasing the reduction ratio of the transmission. At the same time, it is convenient to transmit the torque load generated by the increased eccentricity directly to the housing (1) through the needle roller (5).

7. A lateral load-resistant lead screw fork anti-rotation guide mechanism according to any one of claims 1-4, characterized in that: The plane of the housing (1) that mates with the needle roller (5) is parallel to the plane of the lead screw nut (4).

8. A lateral load-resistant lead screw fork anti-rotation guide mechanism according to any one of claims 1-4, characterized in that: The plane where the housing (1) mates with the needle roller (5) is hardened.

9. A lateral load-resistant lead screw fork anti-rotation guide mechanism according to any one of claims 1-4, characterized in that: A flat plate with a surface hardness of not less than 50HRC is embedded between the housing (1) and the needle roller (5).

10. A lateral load-resistant lead screw fork anti-rotation guide mechanism according to any one of claims 1-4, characterized in that: The needle roller (5) and the housing (1) need to be lubricated during the contact and mating process, including: uniformly applying grease to the surface of the needle roller (5), spraying molybdenum disulfide, or embedding solid lubricating particles on the mating plane between the needle roller (5) and the housing (1).

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