Flexible supporting structure for wave generator of harmonic reducer of steering engine

Abstract

The invention discloses a wave generator flexible supporting structure of a harmonic reducer of a steering engine, which comprises a flexible gear output assembly and a wave generator assembly sleeved on the flexible gear output assembly, and the diameter d of an output shaft at the supporting position of the wave generator assembly on the flexible gear output assembly is equal to D-(2-4) * delta; when the diameter of an output shaft at the supporting position of the wave generator assembly on the flexible gear output assembly is larger than or equal to 10 mm, an annular groove is formed in the center of the supporting position, and a rubber O-shaped sealing ring is arranged in the annular groove. A gap is kept between the output shaft and the wave generator, and the O-shaped sealing ring is in flexible contact, so that even if the output shaft is bent and deformed, the output shaft and the wave generator are not in rigid contact, bending deformation has no additional acting force on the wave generator, and flexible operation of the wave generator and normal work of the steering engine are guaranteed. The annular groove is formed, the rigidity of the output shaft is weakened, the stress condition of the small bearing is greatly reduced, and the radial load of the small bearing can be reduced by 50%-70%. And under the same volume, weight and motor power, the bending moment bearing capacity is improved by 2-3 times.

Description

Technical Field

[0001] The invention relates to a wave generator flexible support structure of a steering gear harmonic reducer, belonging to the technical field of steering gear harmonic reducers. Background Art

[0002] Servo actuators are the terminal actuators of guidance systems for aircraft such as missiles, rockets, and drones. They receive instructions from the flight control system or the host computer, accurately and quickly drive the deflection of the control surface, and change the aerodynamic torque acting on the control surface, so as to achieve the purpose of stabilizing themselves and correcting the trajectory to hit the target. Today, with the rapid development of modern warfare, the way of warfare is changing rapidly. Equipment not only has supersonic cruise, super stealth, and super maneuverability, but also has the ability of autonomous trajectory planning. Higher requirements are placed on the dynamic response and load-bearing capacity of servo actuators, especially for ultra-high speed and large-angle turns. The actuators not only need to maintain a large output torque, but also need to resist extremely large shear bending moment loads.

[0003] The servo steering gear is composed of a motor, a reducer, a sensor, a controller, etc. The reducer is usually a harmonic reducer, and the structure is that the high-speed stage uses a bevel gear transmission input to achieve a 90° turn, and the low-speed stage uses a harmonic gear transmission to achieve a high-precision output. The output shaft of the harmonic reducer undergoes a large bending deformation under the action of a huge shear bending moment load, and the wave generator will bear additional radial extrusion loads. The operating resistance of the wave generator (large bevel gear) increases, causing the motor to be unable to drive the reducer to work normally, and ultimately leading to mechanism failure and even mission failure.

[0004] In order to improve the anti-bending moment capability of the servo actuator, the supporting rigidity of the output shaft is usually enhanced, and multiple bearings are installed outside the reducer to resist the bending moment. For example, CN102765475A discloses an aircraft and an anti-high-bending-moment electric actuator thereof. This solution increases the overall size and weight of the servo actuator, and does not meet the target requirements of lightweight and miniaturization. Summary of the invention

[0005] The purpose of the present invention is to provide a flexible support structure for a wave generator of a harmonic reducer of a steering gear. The present invention eliminates the additional radial extrusion load on the wave generator caused by the bending deformation of the output shaft under the action of the shear bending moment, thereby ensuring the flexible operation of the wave generator and the normal operation of the reducer. Under the same volume, weight and motor power, the moment bearing capacity is increased by 2-3 times, which greatly improves the bearing capacity and reliability of the servo steering gear.

[0006] The technical solution of the present invention is as follows: a wave generator flexible support structure of a steering gear harmonic reducer comprises a flexible wheel output assembly and a wave generator assembly sleeved thereon, wherein the output shaft diameter d=D-(2-4)*δ of the wave generator assembly support position on the flexible wheel output assembly, wherein D is the inner ring diameter of the center bearing of the wave generator assembly, and δ is the maximum bending deformation of the output shaft of the flexible wheel output assembly under the action of bending moment; The servo wave reducer includes a shell, a front end cover is connected to the front end of the shell, and an installation chamber is formed inside the two. A flexible wheel output assembly is installed in the installation chamber, and a wave generator assembly, a spacer sleeve and a small bearing are sequentially sleeved on the output shaft of the flexible wheel output assembly from right to left. A small bevel gear motor assembly is installed on the shell, and the small bevel gear of the small bevel gear motor assembly extends into the installation chamber and meshes with the large bevel gear on the wave generator assembly.

[0007] The wave generator assembly includes a central bearing, a large bevel gear is sleeved on the central bearing, the outer circle contour of the boss on the back cone side of the large bevel gear is an elliptical cam, a flexible bearing is sleeved on the elliptical cam, a baffle is arranged on the outer side of the central bearing, and the baffle is fixed to the large bevel gear by screws.

[0008] In the aforementioned wave generator flexible support structure of a servo harmonic reducer, when the output shaft diameter of the wave generator component support position on the flexible wheel output assembly is ≥10mm, an annular groove is provided at the center of the support position, and a rubber O-ring is provided in the annular groove.

[0009] In the aforementioned flexible support structure of the wave generator of the steering gear harmonic reducer, the width of the annular groove is a=(1.2~1.5)*d0, and the radial compression of the rubber O-ring after assembly is k=d0-h=(0.1~0.2)*d0, where d0 is the wire diameter of the rubber O-ring and h is the groove depth of the annular groove.

[0010] In the aforementioned wave generator flexible support structure of a servo harmonic reducer, the width b of the wave generator assembly support position on the flexspline output assembly = (1.1-1.2) * B, where B is the inner ring width of the center bearing of the wave generator assembly.

[0011] Beneficial effects of the present invention: Compared with the prior art, the benefits of using the wave generator flexible support structure are shown in the following aspects: 1) There is a gap between the output shaft and the wave generator, and the elastic element (O-ring) is in flexible contact. Even if the output shaft is bent, there is no rigid contact between the output shaft and the wave generator. The bending deformation has no additional force on the wave generator, ensuring the flexible operation of the wave generator and the normal operation of the servo.

[0012] 2) The annular groove is set to weaken the rigidity of the output shaft and greatly reduce the stress condition of the small bearing. The radial load of the small bearing can be reduced by 50%-70%.

[0013] 3) With the same volume, weight and motor power, the bending moment bearing capacity is increased by 2-3 times.

[0014] In summary, the present invention adopts the above scheme. After theoretical calculation and engineering verification, under the same volume, weight and motor power, the bending moment bearing capacity is increased by 2-3 times, and the radial load of small bearings can be reduced by 50%-70%. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the structure of the invention; Figure 2 This is a schematic diagram of the transmission mechanism of the servo harmonic reducer; Figure 3 It is an exploded view of the steering gear harmonic reducer of the present invention; Figure 4 It is an assembly diagram of the steering gear harmonic reducer of the present invention; Figure 5 It is a schematic diagram of the output shaft of the flexible wheel output assembly; Figure 6 Assembly diagram for the wave generator assembly.

[0016] Figure markings: 1. fastener, 2. front end cover, 3. flexible wheel output assembly, 4. rubber O-ring, 5. wave generator assembly, 5-1. flexible bearing, 5-2. baffle, 5-3. center bearing, 5-4. screw, 5-5. large bevel gear, 5-5.1. elliptical cam, 6. spacer, 7. small bearing, 8. housing, 9. small bevel gear motor assembly, 10. annular groove. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0018] An embodiment of the present invention: A wave generator flexible support structure of a steering gear harmonic reducer comprises a flexible wheel output assembly 3 and a wave generator assembly 5 sleeved on the output shaft of the flexible wheel output assembly 3, wherein the output shaft diameter d=D-(2-4)*δ at the supporting position of the wave generator assembly 5 on the output shaft of the flexible wheel output assembly 3, wherein D is the inner ring diameter of the center bearing 5-3 of the wave generator assembly 5, the output shaft of the flexible wheel output assembly 3 passes through the center bearing 5-3, and δ is the maximum bending deformation of the output shaft of the flexible wheel output assembly 3 under the action of bending moment.

[0019] Depend on Figure 2It can be seen that the output shaft of the harmonic reducer for the steering gear is generally supported by two front and rear ball bearings. Under the action of the external shear moment load M, the output shaft bends and deforms with the two bearings as fulcrums.

[0020] The bending radial deformation δ of the flexwheel output component 3 at the support position of the wave generator component 5 is obtained by simulation or theoretical calculation, and the output shaft diameter d at the support position of the wave generator component 5 on the output shaft of the flexwheel output component 3 is reduced by (2 to 4) times the bending radial deformation δ.

[0021] During operation, the wave generator assembly 5 is kept rotating around the center of the flexible wheel by relying on the cooperation between the flexible wheel and the flexible bearing 3-1 on the flexible wheel output assembly 3. When the output shaft of the flexible wheel output assembly 3 is bent and deformed by the shear bending moment, since the radial clearance between the wave generator assembly 5 and the output shaft support position is greater than the output shaft bending radial deformation, the bending deformation has no additional effect on the wave generator assembly 5, ensuring that the output shaft bending deformation has no effect on the support of the wave generator assembly 5.

[0022] For the output shaft diameter of the wave generator component 5 supporting position on the flexible wheel output component 3 that is greater than or equal to 10 mm, an annular groove 10 is set at the center of the support position of the wave generator component 5 on the output shaft, and a rubber O-ring 4 is set in the annular groove 10. Since the annular groove 10 is set on the output shaft of the flexible wheel output component 3, the rigidity of the output shaft is weakened, and the stress condition of the output shaft end support bearing, the small bearing 7, is effectively reduced.

[0023] The width of the annular groove 10 is a=(1.2~1.5)*d0, and the radial compression amount of the rubber O-ring 4 after assembly is k=d0-h=(0.1~0.2)*d0, d0 is the wire diameter of the rubber O-ring 4, and h is the groove depth of the annular groove 10. The wave generator assembly 5 is flexibly supported by the elastic deformation of the rubber O-ring 4.

[0024] Taking the cup-type flexible wheel structure as an example, the applicability of servo harmonic reducers with other structural forms is not excluded.

[0025] The servo harmonic reducer is mainly composed of fasteners 1, front cover 2, flexible wheel output shaft assembly 3, rubber O-ring 4, wave generator 5, spacer 6, small bearing 7, housing 8, and small bevel gear motor assembly 9. The front cover 2 is fixed to the front end face of the housing 8 by fasteners 1, and an installation chamber is formed inside the two. The flexible wheel output assembly 3 is installed in the installation chamber. The wave generator assembly 5, spacer 6 and small bearing 7 are sequentially sleeved on the output shaft of the flexible wheel output assembly 3 from right to left. A small bevel gear motor assembly 9 is installed on the housing 8. The small bevel gear of the small bevel gear motor assembly 9 extends into the installation chamber and meshes with the large bevel gear 5-5 on the wave generator assembly 5. The rubber O-ring 4 is installed in the annular groove 10 of the flexible wheel output shaft assembly 3. The flexible wheel output shaft assembly 3 consists of a flexible wheel and an output shaft, such as Figure 3 As shown, the flexible wheel is fixed to the output shaft by screws, and two bearings are sleeved side by side on the left end of the output shaft.

[0026] The wave generator assembly 5 is composed of a baffle 5-2, a large bevel gear 5-5, a flexible bearing 5-1, a center bearing 5-3, and screws 5-4. The large bevel gear 5-5 is sleeved on the center bearing 5-3. The outer profile of the boss on the back cone side of the bevel gear 5-5 is an elliptical cam 5-5.1. The flexible bearing 5-1 is sleeved on the elliptical cam 5-5.1. A baffle 5-2 is arranged on the outside of the center bearing 5-3. The baffle 5-2 is fixed to the large bevel gear 5-5 by screws 5-4. Figure 1 and Figure 4 It can be seen that the wave generator assembly 5 is sleeved on the output shaft of the flexspline output shaft assembly 3 , specifically, the center bearing 5 - 3 is sleeved on the output shaft, and the outer ring of the flexible bearing 5 - 1 cooperates with the annular inner wall of the flexspline of the flexspline output shaft assembly 3 .

[0027] The structure of the servo harmonic reducer and the structure of the wave generator assembly 5 are both prior arts, and their specific structures will not be described in detail here.

[0028] The inner ring diameter of the center bearing 5-3 of the wave generator assembly 5 is D and the width is B. The diameter corresponding to the installation position of the wave generator assembly 5 on the output shaft is d and the width is b, and an annular groove 10 is provided, and the groove width a and the groove depth h of the annular groove 10 are selected. The wire diameter of the rubber O-ring 4 is selected as d0. The maximum bending deformation of the output shaft of the flexible wheel output shaft assembly 3 under the action of the bending moment is δ. The compression amount of the rubber O-ring 4 is K. The dimension parameters of the flexible support structure are designed as follows: d = D - (2~4) * δ; b=(1.1~1.2)*B; K=d0-h=(0.1~0.2)*d0; a=(1.2~1.5)*d0.

[0029] In addition, the output shaft of the flexible output shaft assembly 3 is supported by two front and rear bearings (such as Figure 4 As shown, the left end of the output shaft is supported in the front end cover 2 by two bearings arranged side by side, while the right end of the output shaft is supported in the housing 8 by a small bearing 7). Under the action of the bending moment, the small bearing 7 resists deformation and bears a large radial force. After the annular groove 10 is provided, the rigidity of the output shaft is weakened, and the stress condition of the small bearing 7 is greatly reduced.

[0030] By adopting the above scheme, after theoretical calculation and engineering verification, under the same volume, weight and motor power, the bending moment bearing capacity can be increased by 2-3 times, and the radial load of small bearings can be reduced by 50%-70%.

Claims

1. A wave generator flexible support structure of a steering gear harmonic reducer, comprising a flexible wheel output assembly (3) and a wave generator assembly (5) sleeved thereon, characterized in that: The output shaft diameter d of the wave generator assembly (5) supporting position on the flexible wheel output assembly (3) is D-(2-4)*δ, wherein D is the inner ring diameter of the center bearing (5-3) of the wave generator assembly (5), and δ is the maximum bending deformation of the output shaft of the flexible wheel output assembly (3) under the action of bending moment; The steering gear wave reducer comprises a housing (8), the front end of the housing (8) is connected to a front end cover (2), the two form an installation chamber inside, a flexible wheel output assembly (3) is installed in the installation chamber, a wave generator assembly (5), a spacer sleeve (6) and a small bearing (7) are sleeved on the output shaft of the flexible wheel output assembly (3) from right to left in sequence, a small bevel gear motor assembly (9) is installed on the housing (8), and the small bevel gear of the small bevel gear motor assembly (9) extends into the installation chamber and meshes with the large bevel gear (5-5) on the wave generator assembly (5); The wave generator assembly (5) comprises a central bearing (5-3), a large bevel gear (5-5) is sleeved on the central bearing (5-3), the outer contour of the boss on the back cone side of the large bevel gear (5-5) is an elliptical cam (5-5.1), a flexible bearing (5-1) is sleeved on the elliptical cam (5-5.1), a baffle (5-2) is arranged on the outside of the central bearing (5-3), and the baffle (5-2) is fixed to the large bevel gear (5-5) via screws (5-4).

2. The wave generator flexible support structure of the steering gear harmonic reducer according to claim 1, characterized in that: When the output shaft diameter of the wave generator assembly (5) supporting position on the flexible wheel output assembly (3) is ≥10 mm, an annular groove (10) is provided at the center of the supporting position, and a rubber O-shaped sealing ring (4) is provided in the annular groove (10).

3. The wave generator flexible support structure of the steering gear harmonic reducer according to claim 2, characterized in that: The width of the annular groove (10) is a=(1.2-1.5)*d0, and the radial compression amount of the rubber O-ring (4) after assembly is k=d0-h=(0.1-0.2)*d0, where d0 is the wire diameter of the rubber O-ring (4) and h is the groove depth of the annular groove (10).

4. The wave generator flexible support structure of the steering gear harmonic reducer according to claim 1, characterized in that: The width b of the support position of the wave generator assembly (5) on the flexible wheel output assembly (3) is (1.1-1.2)*B, where B is the inner ring width of the central bearing (5-3) of the wave generator assembly (5).

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