Gear structure, speed reducer and robot

Abstract

The invention provides a gear structure, a speed reducer and a robot, the gear structure comprises a main body, the main body is provided with a plurality of gear teeth, and the tooth thicknesses of every two adjacent gear teeth are different. According to the industrial robot, the technical problem that in the prior art, mechanical noise generated by a gear in an industrial robot is large, and the use experience is affected can be solved.

Description

Technical Field

[0001] This invention belongs to the field of robotics technology, specifically relating to a gear structure, a speed reducer, and a robot. Background Technology

[0002] With the rapid development of the intelligent manufacturing equipment industry, robotics technology is receiving increasing attention from various enterprises. However, the increase in the number of automated intelligent devices in workshops has also led to a significant rise in noise levels, and noise pollution has become a major factor affecting the physical and mental health of production workshop workers. Currently, most designers focus on improving the work efficiency and control precision of robotic arms during the research and development of industrial robots, often neglecting the potential harm of mechanical noise to user experience and operator health.

[0003] Due to the high mechanical noise generated by gears in existing industrial robots, which affects the user experience, this invention studies and designs a gear structure, a reducer, and a robot. Summary of the Invention

[0004] Therefore, the present invention provides a gear structure, a reducer, and a robot that can solve the technical problem of high mechanical noise generated by gears in existing industrial robots, which affects the user experience.

[0005] To address the aforementioned problems, the present invention provides a gear structure comprising: a main body having a plurality of teeth, wherein the tooth thickness of adjacent teeth is different.

[0006] In some embodiments, the tooth thicknesses of the plurality of said teeth are arranged sequentially according to a sine function curve.

[0007] In some embodiments, the tooth thickness of the plurality of said teeth satisfies,

[0008]

[0009] Where S0 is the nominal tooth thickness, Sn is the tooth thickness of the nth tooth along the tooth arrangement order, with S0 as the first tooth; a' is the tooth thickness difference fluctuation threshold; z is the number of gear teeth; and n is the tooth sequence number.

[0010] In some embodiments, any one tooth on the main body is taken as the first tooth, and the tooth thickness of the plurality of teeth is arranged in a sine function curve in a counterclockwise direction starting from the first tooth.

[0011] The present invention also provides a speed reducer, including the gear structure described above.

[0012] In some embodiments, the driving gear or driven gear in the reducer adopts the gear structure described above.

[0013] The present invention also provides a robot including the aforementioned reducer.

[0014] The gear structure, reducer, and robot provided by this invention have the following beneficial effects:

[0015] By varying the tooth thickness of adjacent teeth, the transmission error is periodically disrupted due to the slight deviation in the meshing of each tooth. This induces the diffusion of the main peak energy of the excitation spectrum, dispersing the noise energy to the sidebands, thereby reducing the noise peak and vibration response during gear pair transmission. Attached Figure Description

[0016] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the tooth thickness in the gear structure of the present invention;

[0018] Figure 2 This is a diagram illustrating the variation of tooth thickness in the gear structure of this invention;

[0019] Figure 3 This is a comparative analysis diagram of the angular acceleration of the gear pair in the gear structure of the present invention under the working conditions of a rotational speed of 1000 r / min and a load of 50 N·m.

[0020] Figure 4 This is a comparative analysis diagram of the angular acceleration of the gear pair in the gear structure of the present invention under the working conditions of a rotational speed of 1000 r / min and a load of 400 N·m;

[0021] Figure 5 This is a comparative analysis diagram of the angular acceleration of the gear pair in the gear structure of the present invention under the working conditions of a rotational speed of 5000 r / min and a load of 50 N·m.

[0022] Figure 6 This is a comparative analysis diagram of the angular acceleration of the gear pair in the gear structure of the present invention under the working conditions of a rotational speed of 5000 r / min and a load of 400 N·m.

[0023] Figure 7 This is a comparative analysis diagram of the meshing force of the gear pair in the gear structure of the present invention under the working conditions of a rotational speed of 1000 r / min and a load of 50 N·m.

[0024] Figure 8This is a comparative analysis diagram of the meshing force of the gear pair in the gear structure of the present invention under the working conditions of a rotational speed of 1000 r / min and a load of 400 N·m.

[0025] Figure 9 This is a comparative analysis diagram of the meshing force of the gear pair in the gear structure of the present invention under the working conditions of a rotational speed of 5000 r / min and a load of 50 N·m.

[0026] Figure 10 This is a comparative analysis diagram of the meshing force of the gear pair in the gear structure of the present invention under the working conditions of a rotational speed of 5000 r / min and a load of 400 N·m. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0029] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0030] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0031] See also Figure 1-10 As shown, according to an embodiment of the present invention, a gear structure is provided, comprising: a body having a plurality of teeth, wherein the tooth thickness of two adjacent teeth is different.

[0032] In this technical solution, by using the different tooth thicknesses of two adjacent gear teeth, the transmission error is periodically disrupted due to the slight deviation in the meshing of each gear tooth, which induces the diffusion of the main peak energy of the excitation spectrum, causing the noise energy to be dispersed to the sideband, thereby reducing the noise peak and vibration response during gear pair transmission.

[0033] See also Figure 1 As shown, the gear structure of the present invention can achieve the purpose of reducing gear vibration and noise. The tooth thickness of each tooth of the driving gear or driven gear is set inconsistently. (See also...) Figure 8 As shown, it can be observed that the main peaks of Examples 2 and 3 have different degrees of thickening on both sides, while the main peaks of Example 1 are very clean on both sides. This means that the energy of the main peak is dispersed by the side bands.

[0034] In some embodiments, the tooth thicknesses of the plurality of said teeth are arranged sequentially according to a sine function curve.

[0035] In this technical solution, the tooth thickness values ​​of the gear teeth follow a sine function curve, thereby breaking the rules of transmission error excitation and reducing the vibration noise of gear meshing.

[0036] In some implementations, see reference Figure 2As shown, the tooth thickness of the plurality of said gear teeth satisfies,

[0037]

[0038] Where S0 is the nominal tooth thickness, Sn is the tooth thickness of the nth tooth along the tooth arrangement order, with S0 as the first tooth; a' is the tooth thickness difference fluctuation threshold; z is the number of gear teeth; and n is the tooth sequence number.

[0039] It should be noted that the nominal tooth thickness is a national standard value, which is used in the formula. Other tooth thicknesses are calculated by adding or subtracting from this standard value. The tooth thickness variation threshold can be determined through... Figure 2 The threshold value refers to the difference between the highest and lowest points of the sine function, which is analogous to the difference between the thickest and thinnest teeth of a gear. It's important to note that this threshold value cannot be set too high, as this can cause the gear to jam at a certain meshing position. In Tables 1 and 2, values ​​of 0.02 and 0.04 are used to analyze various different threshold values ​​to verify the effectiveness of the vibration reduction and noise reduction scheme, making the results more convincing.

[0040] The tooth thickness of each tooth on a normal gear is varied to obtain a gear model with differentiated tooth thickness. In specific cases, the original gear structure data used in the gear design follows national standards. Taking a spur gear with a module of 2.5 and 32 and 48 teeth as an example, its pressure angle is 20°, face width is 30mm, inner hole radius is 38mm, and tooth thickness is 3.875473mm and 3.876316mm respectively. The tooth thickness difference on each tooth follows a sinusoidal distribution. The specific tooth thickness differences are shown in Tables 1 and 2.

[0041]

[0042]

[0043] It should be noted that in the above formula, n does not correspond to the tooth number in Tables 1 and 2. The n in the formula is calculated by subtracting 1 from the tooth number in Tables 1 and 2. For example, the first tooth should be calculated with n=0, so that the standard value is not added or subtracted.

[0044] In some embodiments, any one tooth on the main body is taken as the first tooth, and the tooth thickness of the plurality of teeth is arranged in a sine function curve in a counterclockwise direction starting from the first tooth.

[0045] It should be noted that the tooth thickness difference between adjacent gear teeth is arranged sequentially from tooth number 1 in the counterclockwise direction under the influence of the sine function curve. In order to better reflect the influence of tooth thickness difference under the sine function arrangement on vibration and noise, as many teeth as possible are designed for investigation, so that the pattern of tooth thickness difference between adjacent gear teeth can be closer to the pattern of the sine function.

[0046] It should be noted that, due to the properties of sine and cosine functions, which are symmetrical about the origin or the Y-axis, the meshing teeth of the two gears will have a phase difference after rotating several revolutions. The phase will change continuously during the rotation, and the setting of the positive and negative phases will not affect the simulation results.

[0047] The gear structure of this invention has been proven feasible through simulation experiments. It employs a driving gear (small gear) assembled with a conventionally designed driven gear (large gear). While ensuring rapid convergence of computational efficiency and without affecting computational accuracy, minor features have been simplified by removing structural elements such as bolt holes, threads, and fillets that have little impact on the calculation results.

[0048] To make the experimental results more convincing, a gear pair consisting of a small gear with 32 teeth (driving gear) and a large gear with normal tooth thickness (driven gear) was set up for simulation verification and analysis. In addition, a repeatable experiment was designed to consist of a small gear with normal tooth thickness (driving gear) and a large gear with 48 teeth (driven gear). The specific gear pair setups are shown in Table 3. Among them, Examples 2 and 3 are the gear pairs of the present invention. The gear pair in Example 1 is compared and analyzed with the gear pairs in Examples 2 and 3, respectively.

[0049]

[0050] The assembled 3D solid model was imported into the multibody dynamics software Adams. The materials of the components were defined, and a rotational kinematic pair of gear shafts was added along the axes of the large and small gears. Using the Step function, a ramp function was applied to the driving gear within 0-0.1s to define the driving force to the corresponding speed, and the driven gear was subjected to a corresponding load, which remained constant within 0.1-1.0s. The final transmission model of the cylindrical spur gear was obtained as follows: Figure 2 As shown.

[0051] Simulations were used to determine the angular acceleration and the resultant force of the meshing forces along the x and y axes for each gear pair under different speeds and loads. The frequency domain plot of the resultant force of the angular acceleration and the meshing forces along the x and y axes for each gear pair as a function of frequency, obtained through Fourier transform, is shown below. Figures 3-10 As shown.

[0052] The following conclusions were drawn from the analysis of the simulation results:

[0053] By observing the position of the harmonics on the horizontal axis of the frequency domain plot for each group at different speeds, the actual meshing frequency perfectly matches the theoretical meshing frequency (obtained using the gear meshing frequency formula fz=N·z / 60). For example, at a speed of 5000 r / min, the theoretical meshing frequency for each gear group is fz=5000·32 / 60=2666.66, and its actual meshing frequency is as follows: Figure 6 As shown, the position of the first harmonic frequency on the horizontal axis perfectly matches the theoretical meshing frequency, verifying the correctness of all transmission models.

[0054] A comparative analysis of the frequency domain diagrams of each gear pair revealed that the low-frequency sideband amplitudes in the angular acceleration and meshing force frequency domain diagrams obtained by the present invention are increased, effectively dispersing peak energy. This results in the first-order frequency amplitudes of the gear pairs obtained by the present invention being lower than those of gear pairs without tooth thickness optimization. Furthermore, the second and third-order frequency amplitudes of the gear pairs obtained by the present invention are also generally lower than those of gear pairs without tooth thickness optimization. The magnitudes of the angular acceleration and meshing force amplitudes, especially the first-order frequency amplitudes, in the frequency domain diagrams reflect the vibration and noise during gear meshing, proving that the invention is feasible in reducing vibration and noise during gear meshing, and that the present invention achieves better vibration and noise reduction than normal profile modification.

[0055] Analysis of Tables 4-9, through comparison of experimental results for gear pairs under different speeds, loads, and tooth counts, shows that the method of this invention is effective under various conditions. Under different operating conditions, the maximum reduction in angular acceleration amplitude reaches 36% for the first harmonic, 66% for the second harmonic, and 67.2% for the third harmonic. Under different operating conditions, the maximum reduction in meshing force amplitude reaches 35.3% for the first harmonic, 67.3% for the second harmonic, and 75.7% for the third harmonic. All data analysis directly indicates that the gear dynamics characteristics of this invention are superior, and indirectly indicates that the gear pairs exhibit less vibration and noise during meshing.

[0056]

[0057] The present invention also provides a speed reducer, including the gear structure described above.

[0058] In some embodiments, the driving gear or driven gear in the reducer adopts the gear structure described above.

[0059] In the speed reducer of this invention, the tooth thickness of each tooth, whether acting as the driving or driven gear, is set inconsistently, with the specific tooth thickness values ​​following a sine function curve. This speed reducer proposes two pairs of gears with differentiated tooth thickness designs, employing the gear tooth thickness structure described above. Due to the slight deviation in the meshing of each tooth, the rule for transmission error excitation is broken, thereby achieving vibration and noise reduction. The speed reducer of this invention controls the tooth thickness parameters of each tooth of the driving gear, ensuring that the tooth thickness of each adjacent pair of teeth is inconsistent, and that the tooth thickness is distributed according to a sine function curve. Because of the slight deviation in the meshing of each tooth, the rule for transmission error excitation is broken, achieving vibration and noise reduction.

[0060] The present invention also provides a robot including the aforementioned reducer.

[0061] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A gear structure, characterized in that: include: The main body has multiple gear teeth, and the tooth thickness of two adjacent gear teeth is different.

2. The gear structure according to claim 1, characterized in that: The tooth thicknesses of the multiple gear teeth are arranged sequentially according to a sine function curve.

3. The gear structure according to claim 1, characterized in that: The tooth thickness of multiple gear teeth satisfies the following conditions: Where S0 is the nominal tooth thickness, Sn is the tooth thickness of the nth tooth along the tooth arrangement order, with S0 as the first tooth; a' is the tooth thickness difference fluctuation threshold; z is the number of gear teeth; and n is the tooth sequence number.

4. The gear structure according to claim 1, characterized in that: Taking any one tooth on the main body as the first tooth, the tooth thicknesses of the multiple teeth are arranged in a counterclockwise direction according to a sine function curve, starting from the first tooth.

5. A speed reducer, characterized in that: The gear structure includes any one of claims 1-4.

6. The gear structure according to claim 5, characterized in that: The driving gear or driven gear in the reducer adopts the gear structure of any one of claims 1-4.

7. A robot, characterized in that: The speed reducer included in any one of claims 5-6.

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