CN105605192A - Optimization method of two-stage straight tooth planet gear - Google Patents

Abstract

The optimization method of the two-stage spur planetary gear provided by the present invention includes a. establishing a static transmission error model, b. obtaining the load value of the gear modification of the spur planetary gear transmission box, and c. obtaining the best The amount of gear modification; the optimization method of the two-stage spur planetary gear provided by the present invention can effectively reduce the vibration and noise of the planetary transmission without improving the machining accuracy of the gear and saving materials as much as possible. It reduces the eccentric load phenomenon of planetary gear meshing, thereby improving the transmission stability of the gears, increasing the load-carrying capacity of the gears, and prolonging the service life of the gears. s damage.

Description

Optimization method of two-stage spur planetary gear

technical field

The invention relates to the mechanical field, in particular to an optimization method for a two-stage spur planetary gear.

Background technique

A planetary gearbox is a mechanism in which multiple planetary gears rotate around a sun gear. It is also a mechanism that reduces the transmission speed ratio and increases the torque of the motor proportionally. Compared with the same kind of ordinary gear box, it has the advantages of stable transmission, large bearing capacity, large transmission ratio in a small space, especially the service life, and it is small in size and beautiful in appearance.

The planetary gearbox is an important part widely used in mechanical transmission. When a pair of gears mesh, due to the unavoidable errors such as tooth pitch and tooth shape, meshing impacts will occur during operation and corresponding to the meshing frequency of the gears. Noise, friction noise also occurs between the tooth surfaces due to relative sliding. Since the gear is the basic part in the transmission of the gearbox, it is necessary to reduce the noise of the gear to control the noise of the gearbox. Generally speaking, the main causes of gear system noise are as follows:

1. Gear design. Improper parameter selection, too small overlap, improper or no modification of the tooth profile, unreasonable gearbox structure, etc. In terms of gear processing, the base joint error and tooth profile error are too large, the tooth side clearance is too large, and the surface roughness is too large.

2. Gear train and gearbox. Assembly eccentricity, low contact accuracy, poor parallelism of the shaft, insufficient rigidity of the shaft, bearing, and support, low rotation accuracy of the bearing, and improper clearance, etc.

3. Other input torque. Fluctuation of load torque, torsional vibration of shafting, balance of motor and other transmission pairs, etc.

The design idea of traditional planetary gearboxes is generally based on the calculation method of combining simplified theory and experience. The gear tooth surface is designed as a standard involute tooth surface, which can theoretically make the gear mesh better, but due to processing and assembly The existence of errors, coupled with the elastic deformation of the gear body and the supporting parts of the gear under the action of the load, makes the meshing surface deviate from the theoretical involute and also causes a certain unbalanced load phenomenon in the meshing area of the gear along the tooth width direction. The gear box produces large vibration and noise; on the other hand, the force on the tooth surface is uneven and the fatigue damage of the gear is accelerated. In order to change the above deficiencies, the traditional method is to improve the manufacturing accuracy level of the entire gearbox and increase the support rigidity of the gears. However, on the one hand, this increases manufacturing difficulty and processing cost, and reduces the working efficiency of the gear box at the same time.

Contents of the invention

In view of this, the present invention provides an optimization method for two-stage spur planetary gears to solve the above problems.

The optimization method of the two-stage spur planetary gear provided by the present invention includes

a. Establish static transfer error model,

b. Obtain the load value of the gear modification of the spur planetary gearbox,

c. Obtain the optimal gear modification amount according to the static transmission error model.

Further, the static transmission error model is:

TE＝θ ₂ r _b2 -θ ₁ r _b1

Among them, TE is the static transmission error, θ ₁ is the actual rotation angle of the driving gear, θ ₂ is the actual rotation angle of the driven gear, r _b1 is the base circle radius of the drive gear, and r _b2 is the base circle radius of the driven gear.

Further, the static transmission error is a motion error generated by gear deformation and gear error under static conditions.

Further, the load value in step b is the rated load of the two-stage spur planetary gearbox.

Further, the amount of gear modification in step c includes tooth profile modification and tooth direction modification.

Furthermore, the minimum value of the static transmission error function is selected as the optimal gear modification amount.

Beneficial effects of the present invention: The optimization method of the two-stage spur planetary gear provided by the present invention can effectively reduce the vibration and noise of the planetary transmission without improving the machining accuracy of the gear and saving materials as much as possible. It reduces the eccentric load phenomenon of planetary gear meshing, thereby improving the transmission stability of the gears, increasing the load-carrying capacity of the gears, and prolonging the service life of the gears. s damage.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and embodiment:

Fig. 1 is a schematic diagram of the principle of the present invention.

Fig. 2 is a schematic diagram of tooth profile modification parameters in the present invention.

Fig. 3 is a schematic diagram of the transmission error peak-to-peak value in the present invention.

Fig. 4 is a schematic diagram of tooth profile modification parameters in the present invention.

Fig. 5 is a schematic diagram of the peak value of the normal load per unit length when the tooth surfaces of the present invention are in contact.

detailed description

The present invention will be further described below in conjunction with accompanying drawing and embodiment: Fig. 1 is the schematic diagram of principle of the present invention, Fig. 2 is the tooth profile modification parameter schematic diagram of the present invention, Fig. 3 is the transmission error peak-to-peak schematic diagram of the present invention, Fig. 4 is The schematic diagram of tooth profile modification parameters in the present invention, and FIG. 5 is a schematic diagram of the normal load peak value per unit length when the tooth surface is in contact with the present invention.

As shown in Figures 1, 2, 3, 4, and 5, the optimization method of the two-stage spur planetary gear of the present invention includes

a. Establish static transfer error model,

b. Obtain the load value of the gear modification of the spur planetary gearbox,

c. Obtain the optimal gear modification amount according to the static transmission error model.

In this embodiment, as shown in Figure 2, the tooth profile modification curves of the two tooth surfaces of the planetary gear include: the starting point of tooth top modification (the right contact surface is point 3, the left contact surface is point 1) and the tooth Root modification starting point (point 4 on the right contact surface, point 2 on the left contact surface), tooth tip modification amount (Δ ₃ on the right contact surface, Δ ₁ on the left contact surface) and tooth root modification amount (right contact surface The surface is Δ ₄ , and the left contact surface is Δ ₂ ). Since the meshing conditions of the tooth top and tooth root are basically the same when the two gears mesh, the principle that the tooth top modification amount is equal to the tooth root modification amount is adopted, that is, Δ ₁ = Δ ₂ and Δ ₃ = Δ ₄ , Taking the modification amount as the design variable, and the peak value of the transmission error as the function value, a series of values are obtained through multiple calculations. For the displacement type excitation, the deformation of the gear teeth under the load and the gear error are combined to represent the static transmission error, that is, the motion error generated by the gear deformation and the gear error under static conditions, defined as the driving gear When rotating a certain angle, the deviation between the actual position (rotation angle) of the driven gear and the theoretical position,

$\mathrm{TE}={\mathrm{\θ}}_2-\frac{{\mathrm{\θ}}_1}{i}$ Formula 1)

The formula along the meshing line direction is expressed as

TE＝θ ₂ r _b2 -θ ₁ r _b1 formula (2)

Among them, TE is the static transmission error, θ ₁ and θ ₂ are the actual rotation angles of the main and passive gears respectively, i is the transmission ratio of the gears, and r _b1 and r _b2 are the base circle radii of the main and passive gears respectively.

In this embodiment, as shown in a and b in FIG. 3 , finding the modification amount corresponding to the minimum function value is the optimal tooth profile modification amount. The tooth profile modification of the second-stage planetary transmission is also determined by the same method as that of the first-stage planetary transmission, and the transmission error functions are shown in c and d in Figure 3.

In this embodiment, the method of drum shape modification is adopted, and two different contact surfaces are respectively subjected to drum shape modification. As shown in Figure 4, two different tooth surface crown modification curves include: crown center and crown amount (h for the right contact surface and g for the left contact surface). The drum center is chosen in the middle of the tooth width. The determination of the crowning quantity is to use the crowning quantity as the design variable, and the peak value of the normal load per unit length of the tooth surface is the function value. A series of values are obtained through multiple calculations, as shown in a and b in Figure 5. Find Some values of the function value are smaller, and the load should be distributed in the middle of the tooth surface as much as possible to find the best crowning amount. As shown in c and d in Figure 5, the second-stage planetary transmission tooth modification is also determined by the same method as the first-stage planetary transmission, and its load peak function per unit length.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements without departing from the spirit and scope of the technical solution of the present invention shall be covered by the claims of the present invention.

Claims (6)

1. an optimization method for two-stage straight-tooth planetary gear, is characterized in that: comprise

A. set up quiet transmission error model,

B. obtain the load value of the gear modification of straight-tooth planet gear transmission box,

C. obtain best gear modification amount according to quiet transmission error model.

2. the optimization method of two-stage straight-tooth planetary gear according to claim 1, is characterized in that: described inQuiet transmission error model is:

TE＝θ₂r_b2-θ₁r_b1

Wherein, TE is quiet transmission error, θ₁For driving gear actual rotational angle, θ₂For driven gear actual rotational angle,r_b1For driving gear base radius, r_b2For driven gear base radius.

3. the optimization method of two-stage straight-tooth planetary gear according to claim 2, is characterized in that: described inThe kinematic error of quiet transmission error for being produced by gear shifting quadrant texturing and gear error under static conditions.

4. the optimization method of two-stage straight-tooth planetary gear according to claim 1, is characterized in that: stepLoad value described in b is the rated load of two-stage straight-tooth planet gear transmission box.

5. the optimization method of two-stage straight-tooth planetary gear according to claim 1, is characterized in that: stepThe amount of gear modification described in c comprises profile modification and axial modification.

6. the optimization method of two-stage straight-tooth planetary gear according to claim 5, is characterized in that: chooseThe minimum of a value of quiet transmission error functional value is optimum gear speed profiling quantity.