A small gear train type steering gear and its design method

Abstract

The present invention relates to a small gear train type steering gear and a design method thereof. The steering gear comprises a steering gear housing, a cover plate, a motor, a potentiometer and an inductor. The motor is installed on the steering gear housing through a motor seat. The motor, the inductor and the potentiometer constitute the electrical part of the steering gear. A cavity is formed between the steering gear housing and the cover plate, and the steering gear is characterized in that: a gear assembly and a multi-core cable are also included. The gear assembly is arranged in the cavity and connected to the steering gear housing and the cover plate through a bearing. A motor gear for meshing with the gear assembly is arranged on the motor output shaft. The gear assembly comprises a primary gear assembly, an intermediate gear assembly, a secondary gear assembly, an output gear assembly and an external gear assembly. Each gear assembly meshes and transmits in sequence. The potentiometer is connected to the external gear assembly. The center line of the potentiometer coincides with the center line of the external gear assembly. The width and height of the steering gear are adjusted by the position of the gear assembly. Each signal line of the electrical part is led out to the outside of the steering gear by the multi-core cable.

Description

Technical Field

[0001] The invention relates to a gear train type steering engine and a design method thereof. Background Art

[0002] A servo is an actuator for controlling the control surfaces of an aircraft, and its structure generally includes a motor, a transmission mechanism, and a feedback sensor. Application No. CN103523207 invented an electric servo, which includes a motor, a harmonic cam, an end cover, a servo output shaft, an input steel wheel, a housing, a potentiometer, and a bevel gear assembly. It can achieve flexible connection while ensuring connection stiffness, improve the reliability of the servo and the dynamic response of the servo system, but does not provide ideas for the miniaturization and parameterized design of the servo. Application No. CN105129074 invented a dual-channel electric servo. When working, the motor rotates to drive the screw to rotate through the gear reduction. The ball screw pair converts the rotational motion into linear motion and then drives the rocker arm to rotate through the connecting rod mechanism, thereby realizing torque and speed output, but does not provide ideas for the servo design method and the miniaturization and parameterized design of the servo. Summary of the invention

[0003] The technical problem solved by the present invention is to overcome the deficiencies of the prior art and provide a small gear train type steering engine and a design method thereof.

[0004] The technical solution of the present invention is: a small gear system servo, including a servo housing, a cover plate, a motor, a potentiometer, and an inductor, wherein the motor is installed on the servo housing through a motor seat; the motor, the inductor, and the potentiometer constitute the electrical part of the servo; a cavity is formed between the servo housing and the cover plate, and also includes a gear assembly and a multi-core cable; wherein the gear assembly is arranged in the cavity and connected to the servo housing and the cover plate through a bearing; a motor gear for meshing with the gear assembly is arranged on the motor output shaft, and the gear assembly includes a primary gear assembly, an intermediate gear assembly, a secondary gear assembly, an output gear assembly and an external gear assembly, and each gear assembly meshes and transmits in sequence, the potentiometer is connected to the external gear assembly, the center line of the potentiometer coincides with the center line of the external gear assembly, and the width and height of the servo are adjusted by the position of the gear assembly; each signal line of the electrical part is led out to the outside of the servo by the multi-core cable.

[0005] Preferably, the primary gear assembly, the intermediate gear assembly, the secondary gear assembly, and the output gear assembly in the gear assembly all include a fixedly connected driving gear and a driven gear, the driven gear is driven by the previous gear, and the driving gear drives the next gear.

[0006] Preferably, in the part with bevel gear transmission, a process gap is left between the driven gear and the bearing, the gap size is 0.05mm~0.4mm, and the gap size is adjusted by adding or removing thin gaskets to offset the influence of processing errors during assembly, so that the transmission is smooth and reliable.

[0007] Preferably, the external gear assembly includes an external driven gear, a bearing, an adjusting gasket, an outer pressure plate, and an inner pressure plate, wherein the inner pressure plate constrains the bearing and the adjusting gasket to the driven gear by locking with fasteners; and the outer pressure plate constrains the driven gear, the bearing, the adjusting gasket, and the inner pressure plate to the outer shell by locking with fasteners.

[0008] A design method for a small gear train type steering gear, comprising:

[0009] Determine the height and width of the steering gear according to the size of the steering cabin and nozzle;

[0010] Select the motor;

[0011] Considering the motor no-load speed, servo frequency response speed, servo no-load speed, motor rated torque, servo rated torque and design transmission efficiency, determine the design reduction ratio; based on the design reduction ratio and in combination with the determined servo height and width, determine the transmission form of the gear assembly;

[0012] Calculate the motor operating current and perform current calibration. If the current requirement is met, perform static / dynamic overload multiple calibration. Otherwise, return to re-determine the design reduction ratio or re-select the motor.

[0013] If the static / dynamic overload multiple verification meets the overload multiple requirement, the servo speed verification is performed, otherwise, the system returns to re-determine the design reduction ratio or re-select the motor;

[0014] If the servo speed meets the requirements, the servo design is completed. Otherwise, return to re-determine the design reduction ratio or re-select the motor.

[0015] Preferably, the height and width of the steering gear are determined by:

[0016] Insert the rudder cabin, nozzle and partition tool models in the assembly environment. The rudder cabin and nozzle are used to limit the space of the servo model, and the partition tool model is used to divide the space area when multiple servos are arranged;

[0017] In the assembly environment, the outer circle of the servo housing is set to coincide with the inner circle of the rudder cabin, the servo cover is set to be tangent to the outer circle of the nozzle inside the rudder cabin, and the servo model is made not to exceed the partition tool model, thereby determining the height and width of the servo.

[0018] Preferably, the designed reduction ratio is determined by:

[0019] Calculate the motor no-load speed based on the motor speed constant and the servo rated voltage;

[0020] The maximum reduction ratio I is calculated from the motor no-load speed and the steering gear frequency response speed; the maximum reduction ratio II is calculated from the motor no-load speed and the steering gear no-load speed; the optimal reduction ratio is calculated from the motor rated torque, the steering gear rated torque and the designed transmission efficiency;

[0021] Select the design reduction ratio that meets the following conditions:

[0022] Designed reduction ratio = n × optimal reduction ratio; 0.2≤n≤2;

[0023] Designed reduction ratio < maximum reduction ratio I;

[0024] Designed reduction ratio < maximum reduction ratio II.

[0025] Preferably, a three-dimensional model of the gear in the gear assembly is established; the three-dimensional model is used to realize parametric modeling of the gear, and when the three-dimensional model of the gear is changed, the solid projection curve and its size on the two-dimensional diagram of the gear are changed accordingly; wherein the variables defined in the three-dimensional model are: module m, number of teeth z, displacement coefficient x, tooth width b; and tooth top circle diameter d a , pitch circle diameter d, tooth root circle diameter d f Equations with each of the above variables;

[0026] Use the three-dimensional model entity structure to constrain the transmission gear pair;

[0027] Establishing a servo modeling reference position, wherein the reference position includes two mutually perpendicular reference planes, which are denoted as reference plane I and reference plane II;

[0028] The center of the output stage gear assembly coincides with the intersection of the two reference planes, the axis of the external gear assembly is located on reference plane I, the primary gear assembly and the secondary gear assembly are located on both sides of reference plane I, respectively, wherein the distance between the axis of the primary gear assembly and reference plane I is V1, the distance between the axis of the primary gear assembly and reference plane II is H1, the distance between the axis of the secondary gear assembly and reference plane I is V2, the distance H1 determines the overall height H of the servo, and the distance V1+V2 determines the overall width V of the servo; then the positions of the primary gear assembly, intermediate stage gear assembly, secondary gear assembly, and output stage gear assembly are determined under the determined height and width of the servo.

[0029] Preferably, the output stage gear assembly and the external gear assembly are aligned by means of engraved lines, wherein the engraved line position of the output stage gear assembly and the engraved line position of the external gear assembly are respectively located at the center position of the tooth groove of the gear and the center position of the gear teeth of the gear.

[0030] Preferably, the static / dynamic overload multiple requirement ranges from 0.8 to 3.

[0031] The beneficial effects of the present invention compared with the prior art are:

[0032] (1) During the design of the steering gear model, the steering cabin and partition tool model are inserted in the assembly environment, and the outer circle of the steering gear housing is set to coincide with the inner wall circle of the steering cabin, the steering gear cover is set to be tangent to the outer circle of the nozzle inside the steering cabin, and the steering gear model does not exceed the partition tool model. When the size of the steering cabin and the nozzle changes, the size of the steering gear housing and the cover changes accordingly. This realizes the rapid change and optimization of the steering gear model.

[0033] (2) Parametric modeling of the gear 3D model and the associative drawing of its 2D drawing are realized, that is, when the gear 3D model is changed, the solid projection curve and its size on the gear 2D drawing will change accordingly. The gear 3D model and its 2D drawing can be quickly changed.

[0034] (3) In the design model, by defining the reference position (i.e., the output shaft axis position as the reference) and constraining the position of the primary gear assembly and the secondary gear assembly, the parametric design of the height and width dimensions of the entire servo is achieved, thereby improving the efficiency of the servo design.

[0035] (4) A design method for a small gear-type servo, mainly including motor selection, reduction ratio design, current verification, static / dynamic overload multiple verification, and servo speed verification. A servo process design scheme is proposed to improve the design efficiency of the servo scheme. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a three-dimensional view of the present invention;

[0037] Figure 2 This is a schematic diagram of the internal gear assembly of the steering gear of the present invention;

[0038] Figure 3 This is a schematic diagram of the relationship between the steering gear reference surface and the gear assembly of the present invention;

[0039] Figure 4 It is a schematic diagram of the motor gear and primary gear assembly of the present invention;

[0040] Figure 5 is a schematic diagram of an external gear assembly of the present invention;

[0041] Figure 6 This is a schematic diagram of the design of the steering gear model of the present invention;

[0042] Figure 7 This is a schematic diagram of the electrical part of the steering gear of the present invention;

[0043] Figure 8 It is a schematic diagram of the three-dimensional model of the gear of the present invention;

[0044] Fig. 9 It is a two-dimensional schematic diagram of the gear of the present invention;

[0045] Fig.10It is a schematic diagram of the master and slave gears of the gear assembly of the present invention;

[0046] Fig.11 The present invention is a flow chart of the steering gear design;

[0047] Fig.12 This is a schematic diagram of motor selection of the present invention;

[0048] Fig.13 This is a schematic diagram of the reduction ratio design of the present invention;

[0049] Fig.14 This is a schematic diagram of current calibration of the present invention;

[0050] Fig.15 This is a schematic diagram of the static / dynamic overload multiple verification of the present invention;

[0051] Fig.16 This is a schematic diagram of the steering gear speed calibration of the present invention.

[0052] Caption

[0053] 11 housing, 12 cover, 13 potentiometer, 14 motor, 15 inductor, 16 gear assembly, 161 primary gear assembly, 162 intermediate gear assembly, 163 secondary gear assembly, 164 output gear assembly, 1641 output gear assembly line, 165 external gear assembly, 1651 external driven gear, 1652 adjustment gasket, 1653 external pressure plate, 1654 internal pressure plate, 1655 external gear assembly line, 17 motor seat, 18 motor gear, 19 bearing, 20 thin gasket, 21 rudder cabin, 22 nozzle, 23 partition tool model, 24 multi-core cable, 25 reference plane I, 26 reference plane II, A1 driven gear, A11 tooth top entity, A12 tooth root entity, A13 tooth core entity, A2 driving gear, B dividing circular surface, d a Tip circle diameter, d Pitch circle diameter, d f Root diameter. DETAILED DESCRIPTION

[0054] The present invention will be further described below in conjunction with the embodiments.

[0055] like Figure 1 , 2As shown, a small gear train type servo includes a housing 11, a cover plate 12, a gear assembly 16, a motor 14, a potentiometer 13, an inductor 15, and a multi-core cable 24. The motor 14 is mounted on the servo housing 11 through a motor seat 17, and a motor gear 18 is arranged on the motor output shaft; a cavity is formed between the housing 11 and the cover plate 12, and the gear assembly is arranged in the cavity and connected to the housing 11 and the cover plate 12 through a bearing 19; the gear assembly 16 includes a primary gear assembly 161, an intermediate gear assembly 162, a secondary gear assembly 163, an output gear assembly 164, and an external gear assembly 165, and each gear assembly is meshed and transmitted in sequence, the potentiometer 13 is connected to the external gear assembly 165, and the center line of the potentiometer 13 coincides with the center line of the external gear assembly 165.

[0056] The primary gear assembly 161, the intermediate gear assembly 162, the secondary gear assembly 163, and the output gear assembly 164 in the gear assembly all include a driven gear A1 and a driving gear A2, which are fixedly connected. The driven gear A1 is driven by the previous gear, and the driving gear A2 drives the next gear. Fig.10 As shown, the figure shows a schematic diagram of a spur gear.

[0057] In places where bevel gear assemblies are used, such as Figure 4 As shown, there is a process gap between the driven gear A1 (the motor gear in this example is a bevel gear, and the driven gear here is gear 161) and the bearing 19, and the gap size is 0.05mm~0.4mm. The gap size is adjusted by adding or removing thin gaskets 20, which can offset the influence of processing errors during assembly and make the transmission smooth and reliable.

[0058] like Figure 5 As shown, the external gear assembly 165 includes an external driven gear 1651, a bearing 19, an adjusting gasket 1652, an external pressure plate 1653, and an internal pressure plate 1654, wherein the internal pressure plate 1654 constrains the bearing 19 and the adjusting gasket 1652 to the driven gear 1651 by means of screw locking; and the external pressure plate 1653 constrains the driven gear 1651, the bearing 19, the adjusting gasket 1652, and the internal pressure plate 1654 to the outer shell 11 by means of screw locking.

[0059] The electrical part of the steering gear includes a motor 14, an inductor 15, and a potentiometer 13, among which, Figure 7 As shown, the motor 14 is connected in series with the inductor 15, and each signal line is led out to the outside of the steering gear by a multi-core cable 24.

[0060] The present invention provides a design method for a small gear train type steering gear. Fig.11As shown, it mainly includes motor selection, reduction ratio design, current verification, static / dynamic overload multiple verification, servo speed verification, and servo model design. Among them, when one of the current verification, static / dynamic overload multiple verification, and servo speed verification does not meet the requirements, the motor selection or reduction ratio design is re-performed; when the current verification, static / dynamic overload multiple verification, and servo speed verification all meet the requirements, the servo design is completed. The static / dynamic overload multiple requirement range is 0.8 to 3.

[0061] During the design of the servo model, Figure 6 As shown, the steering cabin 21, the nozzle 22 and the partition tool model 23 are inserted in the assembly environment, wherein the steering cabin 21 and the nozzle 22 are used to limit the space of the steering gear model, and the partition tool model 23 is used to divide the space area when multiple steering gears are arranged. In the assembly environment, the outer circle of the steering gear housing 11 is set to coincide with the inner wall circle of the steering cabin 21, the steering gear cover plate 12 is set to be tangent to the outer circle of the nozzle 22 inside the steering cabin 21, and the steering gear model does not exceed the partition tool model 23. When the size of the steering cabin 21 and the nozzle 22 is changed, the size of the steering gear housing 11 and the cover plate 12 is changed accordingly.

[0062] Motor selection, such as Fig.12 As shown, it includes the calculation of servo power, frequency response output power, and required motor power. Among them, the servo power is calculated by the rated speed and rated torque of the servo; the servo frequency response output power is calculated by the servo frequency characteristics; the required motor power is calculated by the servo power and the design transmission efficiency. The design transmission efficiency ranges from 0.3 to 1.

[0063] P 额定 =T 额定 ·ω 额定

[0064] ω 频响 =0.707×θ·2π·f

[0065] P 频响 =T 频响 ·ω 频响

[0066] P 电机 =P 额定 / η

[0067] Among them, T 额定 is the rated torque of the servo, ω 额定 is the rated speed of the servo, θ is the dynamic amplitude characteristic of the servo, f is the dynamic frequency characteristic of the servo, ω 频响 is the dynamic speed of the servo, P 额定 is the servo power, P 频响 is the frequency response output power of the servo, η is the design transmission efficiency, P 电机 is the required motor power.

[0068] Reduction ratio design, such as Fig.13 As shown, it includes the calculation of motor no-load speed, servo frequency response speed, maximum reduction ratio I, maximum reduction ratio II, and optimal reduction ratio, as well as the determination of design reduction ratio, design transmission form, and design transmission efficiency. Among them, the motor no-load speed is calculated by the motor speed constant and the rated voltage of the servo; the maximum reduction ratio I is calculated by the motor no-load speed and the servo frequency response speed; the maximum reduction ratio II is calculated by the motor no-load speed and the servo no-load speed; the optimal reduction ratio is calculated by the motor rated torque, the servo rated torque and the design transmission efficiency; the design reduction ratio = n × optimal reduction ratio (0.2≤n≤2), the design reduction ratio < maximum reduction ratio I, the design reduction ratio < maximum reduction ratio II; the design transmission form includes straight teeth, bevel teeth, and worm gears; the design transmission efficiency is calculated by the design transmission form.

[0069] n 电机空载 =k n ·V

[0070] i 最大Ⅰ =n 电机空载 / n 频响

[0071] i 最大Ⅱ =n 电机空载 / n 空载

[0072] i 最佳 =n 电机额定 / n 额定

[0073] i=n·i 最佳 0.2≤n≤2

[0074] i 最大Ⅰ ,i 最大Ⅱ

[0075] where k n is the motor speed constant, V is the rated voltage of the servo, n 电机空载 is the no-load speed of the motor, n 频响 is the servo frequency response speed, n 空载 is the no-load speed of the servo, i 最大Ⅰ is the maximum reduction ratio Ⅰ, i 最大Ⅱ is the maximum reduction ratio II, i 最佳 is the optimal reduction ratio, and i is the designed reduction ratio.

[0076] Current calibration, such as Fig.14 As shown, including the calculation of the motor working current, the motor working current is calculated based on the servo design transmission efficiency, rated torque, design reduction ratio and motor torque constant.

[0077] I=T​​额定 / i·η·k m

[0078] Where T 额定 is the rated torque of the servo, k m is the motor torque constant. Static / dynamic overload multiple verification, such as Fig.15 As shown, it includes the calculation of the required motor static torque, required motor dynamic torque, static overload multiple, and dynamic overload multiple. Among them, the required motor static torque is calculated by the servo rated torque, design transmission efficiency, and design reduction ratio; the required motor dynamic torque is calculated by the servo frequency characteristics, moment of inertia, design reduction ratio, and design transmission efficiency; static overload multiple = required motor static torque / motor rated torque; dynamic overload multiple = required motor dynamic torque / motor rated torque.

[0079]

[0080]

[0081]

[0082]

[0083] Where T 电机静态 is the required motor static torque, T 电机动态 is the required motor dynamic torque, J is the system moment of inertia, T 电机额定 is the rated torque of the motor, N 静态 is the static overload multiple, N 动态 It is the dynamic overload multiple.

[0084] Steering gear speed calibration, such as Fig.16 As shown, it includes the calculation of motor no-load speed, motor loaded speed, servo no-load speed, and servo loaded speed. Among them, the motor no-load speed is calculated by the motor rated voltage, speed constant and servo rated voltage; the motor loaded speed is calculated by the motor rated voltage, speed constant, speed / torque slope and the servo rated voltage, rated torque, design transmission efficiency, and design reduction ratio; servo no-load speed = motor no-load speed / design reduction ratio; servo loaded speed = motor loaded speed / design reduction ratio.

[0085]

[0086] n 空载 =n 电机空载 / i

[0087] n 带载 =n 电机带载 / i

[0088]

[0089]

[0090] in is the motor speed / torque slope, n 电机带载 is the motor load speed, n 空载 is the no-load speed of the servo, n 带载 It is the servo load speed.

[0091] After determining the design reduction ratio, the present invention needs to design a specific gear assembly according to the determined steering gear width and height.

[0092] The gear 3D model consists of 3 entities, such as Figure 8 As shown: tooth top entity A11, tooth root entity A12, tooth core entity A13. The outer diameter of the tooth top entity A11 is the tooth top circle diameter d of the gear. a ; The inner diameter of the tooth top entity A11 is equal to the outer diameter of the tooth root entity A12, which is the pitch circle diameter d of the gear; the inner diameter of the tooth root entity A12 is the root circle diameter d of the gear f . The diameter of the tooth tip circle of the gear is d a , pitch circle diameter d, tooth root circle diameter d f All of them can be calculated from the gear module m, number of teeth z, and modification coefficient x. In the three-dimensional model, the variables are defined as: module m, number of teeth z, modification coefficient x, tooth width b, and tooth top circle diameter d. a , pitch circle diameter d, tooth root circle diameter d f With the equations of various variables, parametric modeling of gears can be achieved.

[0093] The three entities contained in the gear 3D model can be projected and displayed in a 2D diagram, such as Fig. 9 As shown, by dimensioning and changing the line type of the solid projection curve, the associative drawing of the gear two-dimensional drawing can be achieved, that is, when the gear three-dimensional model is changed, the solid projection curve and its size on the gear two-dimensional drawing will change accordingly.

[0094] Using the 3D structure of the gear 3D model, the transmission gear pair is constrained to fit, even if the pitch circle surfaces B of the two gear components that transmit each other are tangent, such as Fig.10 shown.

[0095] In the design model, the output stage gear assembly 164 is located at the servo modeling reference position, and the output stage gear assembly 164 coincides with the intersection of the reference plane I 25 and the reference plane II 26, as shown in FIG. Figure 3As shown, the primary gear assembly 161 is meshed with the motor gear 18. The distance between the axis of the primary gear assembly 161 and the reference plane I 25 is V1, the distance between the axis of the primary gear assembly 161 and the reference plane II 26 is H1, and the distance between the axis of the secondary gear assembly and the reference plane I 25 is V2. The distance H1 determines the height H of the entire servo, and the distance V1+V2 determines the width V of the entire servo.

[0096] The output stage gear assembly 164 and the external gear assembly 165 are aligned by means of engraved lines, wherein the position of the output stage gear assembly engraved line 1641 and the position of the external gear assembly engraved line 1655 are located at the center of the tooth groove of the gear and the center of the gear teeth of the gear respectively.

[0097] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

[0098] Parts not described in detail in the present invention belong to common knowledge of those skilled in the art.

Claims

1. A design method for a small gear train servo. Features include: The height and width of the steering gear are determined according to the size of the steering cabin and the nozzle; the steering gear comprises a steering gear housing, a cover plate, a motor, a potentiometer, and an inductor, and the motor is installed on the steering gear housing through a motor seat; The electrical part of the servo is composed of a motor, an inductor and a potentiometer; a cavity is formed between the servo housing and the cover plate, and also includes a gear assembly and a multi-core cable; wherein the gear assembly is arranged in the cavity and connected to the servo housing and the cover plate through a bearing; a motor gear for meshing with the gear assembly is arranged on the motor output shaft, and the gear assembly includes a primary gear assembly, an intermediate gear assembly, a secondary gear assembly, an output gear assembly and an external gear assembly, and each gear assembly is meshed and transmitted in sequence, and the potentiometer is connected to the external gear assembly, and the center line of the potentiometer coincides with the center line of the external gear assembly, and the width and height of the servo are adjusted by the position of the gear assembly; each signal line of the electrical part is led out to the outside of the servo by a multi-core cable; Select the motor; Considering the motor no-load speed, servo frequency response speed, servo no-load speed, motor rated torque, servo rated torque and design transmission efficiency, determine the design reduction ratio; based on the design reduction ratio and in combination with the determined servo height and width, determine the transmission form of the gear assembly; Calculate the motor operating current and perform current calibration. If the current requirement is met, perform static / dynamic overload multiple calibration. Otherwise, return to re-determine the design reduction ratio or re-select the motor. If the static / dynamic overload multiple verification meets the overload multiple requirement, the servo speed verification is performed, otherwise, the system returns to re-determine the design reduction ratio or re-select the motor; If the servo speed meets the requirements, the servo design is completed. Otherwise, return to re-determine the design reduction ratio or re-select the motor.

2. The method according to claim 1, Features Determine the height and width of the servo as follows: Insert the rudder cabin, nozzle and partition tool models in the assembly environment. The rudder cabin and nozzle are used to limit the space of the servo model, and the partition tool model is used to divide the space area when multiple servos are arranged; In the assembly environment, the outer circle of the steering gear housing is set to coincide with the inner wall circle of the steering cabin, the steering gear cover is set to be tangent to the outer circle of the nozzle inside the steering cabin, and the steering gear model is ensured not to exceed the partition tool model.

3. The method according to claim 1, Features The design reduction ratio is determined by: Calculate the motor no-load speed based on the motor speed constant and the servo rated voltage; The maximum reduction ratio I is calculated from the motor no-load speed and the steering gear frequency response speed; the maximum reduction ratio II is calculated from the motor no-load speed and the steering gear no-load speed; Calculate the best reduction ratio based on the motor rated torque, servo rated torque and designed transmission efficiency; Select the design reduction ratio that meets the following conditions: Designed reduction ratio = n × optimal reduction ratio; 0.2≤n≤2; Designed reduction ratio < maximum reduction ratio I; Designed reduction ratio < maximum reduction ratio II.

4. The method according to claim 1, Features: A three-dimensional model of a gear in a gear assembly is established; the three-dimensional model is used to realize parametric modeling of the gear. When the three-dimensional model of the gear is changed, the solid projection curve and its size on the two-dimensional diagram of the gear are changed accordingly; wherein the variables defined in the three-dimensional model are: module m, number of teeth z, displacement coefficient x, tooth width b; and tooth top circle diameter d a , pitch circle diameter d, tooth root circle diameter d f Equations with each of the above variables; Use the three-dimensional model entity structure to constrain the transmission gear pair; Establishing a servo modeling reference position, wherein the reference position includes two mutually perpendicular reference planes, which are denoted as reference plane I and reference plane II; The center of the output stage gear assembly coincides with the intersection of the two reference planes. The axis of the external gear assembly is located on reference plane I. The primary gear assembly and the secondary gear assembly are located on both sides of reference plane I. The distance between the axis of the primary gear assembly and reference plane I is V. 1 , the distance between the primary gear assembly axis and the reference plane II is H 1 , the distance between the axis of the secondary gear assembly and the reference plane I is V 2 , distance H 1 Determine the overall height H and distance V of the servo 1 +V 2 Determine the overall width V of the servo; and then determine the positions of the primary gear assembly, the intermediate gear assembly, the secondary gear assembly, and the output gear assembly based on the height and width of the servo.

5. The method according to claim 4, Features: The output stage gear assembly and the external gear assembly are aligned by means of engraved lines, wherein the engraved line position of the output stage gear assembly and the engraved line position of the external gear assembly are respectively located at the center position of the tooth groove of the gear and the center position of the gear teeth of the gear.

6. The method according to claim 4, Features: The static / dynamic overload multiples are required to range from 0.8 to 3.

7. The method according to claim 1, Features: The primary gear assembly, the intermediate gear assembly, the secondary gear assembly and the output gear assembly in the gear assembly all include a fixed driving gear and a driven gear. The driven gear is driven by the previous gear, and the driving gear drives the next gear.

8. The method according to claim 1, Features: In the parts with bevel gear transmission, a process gap is left between the driven gear and the bearing. The gap size is 0.05mm~0.4mm, and the gap size is adjusted by adding or subtracting thin shims to offset the influence of processing errors during assembly, making the transmission smooth and reliable.

9. The method according to claim 1, Features: The external gear assembly includes an external driven gear, a bearing, an adjusting gasket, an external pressure plate, and an internal pressure plate, wherein the internal pressure plate constrains the bearing and the adjusting gasket to the driven gear by locking with fasteners; and the external pressure plate constrains the driven gear, the bearing, the adjusting gasket, and the internal pressure plate to the outer shell by locking with fasteners.

Images