Differential planetary gear speed reducer

Abstract

The utility model relates to the technical field of speed reducer equipment, in particular to a differential type planetary gear speed reducer. A differential gear shaft used for synchronously driving a first-stage planetary gear speed reducing mechanism and a second-stage planetary gear speed reducing mechanism is arranged in a box body of the differential type planetary gear speed reducer. The differential gear shaft is provided with a first meshing part and a second meshing part. And a differential gear sleeve is arranged between the first-stage planetary gear speed reducing mechanism and the second-stage planetary gear speed reducing mechanism. An output end used for being connected with an output shaft is arranged on a planetary gear support of the second-stage planetary gear speed reducing mechanism. The differential gear sleeve is provided with a first inner gear ring and a second inner gear ring. And the first inner gear ring is meshed with a first planetary gear of the first-stage planetary gear speed reducing mechanism. And the second inner gear ring is meshed with a second planetary gear in the second-stage planetary gear reducing mechanism. According to the differential type planetary gear speed reducer, the structure of an existing speed reducer is optimized, the cost is reduced, the reduction ratio use range of a speed reducer is greatly widened, and the design difficulty is reduced.

Description

Technical Field

[0001] This utility model relates to the field of speed reducer equipment technology, specifically to a differential planetary gear reducer. Background Technology

[0002] A speed reduction device is a mechanical transmission device used to convert high-speed rotation of an input shaft into low-speed rotation of an output shaft, while simultaneously increasing the torque of the output shaft. Common types of speed reduction devices include gear reducers, planetary reducers, worm gear reducers, and harmonic reducers. The appropriate type of speed reduction device can be selected based on the operating conditions.

[0003] Different types of speed reducers have their own limitations on transmission ratio range in their design. For example, harmonic reducers are generally suitable for high transmission ratio applications, while planetary reducers are suitable for medium to low transmission ratio applications. As a result, designers need to combine multiple types of speed reducers in the system design, which increases the design complexity.

[0004] A search revealed a speed reducer in Chinese patent document CN114688219A. This speed reducer features a fork switch on its housing for adjusting the circumferential motion of a speed-regulating gear ring, allowing the gear ring to be in either a fixed or rotatable state. When the gear ring is rotatable, it meshes with the synchronous gear, and the gear ring and planetary reduction mechanism are relatively stationary. When the gear ring is fixed, it cannot rotate circumferentially, disengages from the synchronous gear, and the coupling directly drives the output shaft to rotate via the planetary reduction mechanism, thus achieving speed reduction.

[0005] Although the aforementioned gearbox achieves speed reduction through a multi-stage planetary gear structure and allows for adjustment of both power transmission and deceleration by switching the state of the gear ring, the range of reduction ratios achievable through this multi-stage planetary gear structure is limited, making it difficult to meet the needs of various operating conditions. Especially in robot joint applications, simply increasing the number of stages in the planetary gear structure to improve the adjustment range of the reduction ratio would continuously increase the size and weight of the gearbox, thus affecting the flexibility of the robot joints. Summary of the Invention

[0006] The purpose of this invention is to provide a speed reduction device for power transmission of a motor, which optimizes the structure of existing speed reducers, reduces costs, significantly increases the range of applicable speed reduction ratios, and reduces design difficulty.

[0007] To achieve the above objectives, the present invention adopts the following solution:

[0008] A differential planetary gear reducer includes a housing, a first-stage planetary gear reduction mechanism, and a second-stage planetary gear reduction mechanism;

[0009] The housing is provided with a differential gear shaft for synchronously driving the first-stage planetary gear reduction mechanism and the second-stage planetary gear reduction mechanism. The differential gear shaft is mounted in the housing via bearings and is provided with a first meshing part and a second meshing part.

[0010] A differential gear sleeve is provided between the first-stage planetary gear reduction mechanism and the second-stage planetary gear reduction mechanism. The planetary gear support of the second-stage planetary gear reduction mechanism is provided with an output end for connecting the output shaft. The differential gear sleeve is provided with a first internal gear ring and a second internal gear ring. The first internal gear ring meshes with the first planetary gear of the first-stage planetary gear reduction mechanism, and the second internal gear ring meshes with the second planetary gear in the second-stage planetary gear reduction mechanism.

[0011] Preferably, the first-stage planetary gear reduction mechanism includes a first planetary gear and a first planetary gear support. The first planetary gear support is mounted on the first end of the differential gear shaft via a bearing. The first planetary gear support is provided with a first rotating shaft for supporting the first planetary gear. The first planetary gear is mounted on the first rotating shaft and meshes with the first meshing part of the differential gear shaft.

[0012] Preferably, the two-stage planetary gear reduction mechanism includes a second planetary gear and a second planetary gear support. The second planetary gear support is mounted on the second end of the differential gear shaft via a bearing. A second rotating shaft for supporting the second planetary gear is provided on the second planetary gear support. The second planetary gear is mounted on the second rotating shaft and meshes with the second meshing part of the differential gear shaft.

[0013] Preferably, both the first and second rotating shafts are pins. The first planetary gear is mounted on the first planetary gear support via the pin, and the second planetary gear is mounted on the second planetary gear support via the pin. A retaining ring is provided at the end of the pin.

[0014] Preferably, the output shaft is connected to the output end of the second planetary gear carrier via fasteners.

[0015] Preferably, the end of the differential gear shaft is provided with a connecting flange for mounting a power motor.

[0016] Preferably, the reduction ratio range of the differential planetary gear reducer is 3000:1-5000:1.

[0017] Compared with existing technologies, the differential planetary gear reducer provided by this utility model has the following substantial features and advancements: This differential planetary gear reducer uses a series combination of two-stage planetary gear reduction mechanisms. The second planetary gear meshes with the differential gear sleeve, and a speed difference exists between them, creating relative motion. Utilizing this speed difference, the speed of the planetary gear support in the second-stage planetary gear reduction mechanism is significantly reduced. This not only meets different reduction requirements but also significantly reduces the output shaft speed while maintaining high-speed rotation of the input shaft, adapting to more application scenarios. The design of the differential gear shaft and differential gear sleeve effectively reduces losses during transmission. Compared with traditional multi-stage planetary gear transmission methods, it reduces energy loss and improves overall transmission efficiency. Through the design of the two-stage planetary gear reduction mechanism, this differential planetary gear reducer can maintain high load-bearing capacity while providing a high reduction ratio. The differential gear shaft is mounted in the housing through bearings, ensuring its smooth operation, significantly improving the range of reduction ratios that the reduction device can handle, and reducing design complexity. Attached Figure Description

[0018] Figure 1 This is a structural schematic diagram of a differential planetary gear reducer according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the assembly structure of a differential planetary gear reducer according to an embodiment of this utility model.

[0020] Reference numerals: 1. Housing; 2. First-stage planetary gear reduction mechanism; 3. Second-stage planetary gear reduction mechanism; 4. Differential gear shaft; 5. Differential gear sleeve; 6. Output shaft; 7. Shaft retaining ring; 21. First planetary gear; 22. First planetary gear support; 23. First rotating shaft; 31. Second planetary gear; 32. Second planetary gear support; 33. Second rotating shaft; 41. First meshing part; 42. Second meshing part; 51. First internal gear ring; 52. Second internal gear ring. Detailed Implementation

[0021] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0022] like Figures 1-2 As shown in the present invention, a differential planetary gear reducer is proposed in this embodiment, which aims to optimize the structure of existing reducers, reduce costs, significantly improve the range of reduction ratios of the reduction device, and reduce design difficulty.

[0023] This utility model proposes a differential planetary gear reducer that reduces the speed of a power motor by arranging a first-stage planetary gear reduction mechanism 2 and a second-stage planetary gear reduction mechanism 3 in a housing 1. The structural design of the differential gear shaft 4 and differential gear sleeve 5 makes the entire reduction device more compact, saving space and facilitating efficient speed reduction within limited installation space, thus reducing costs and design complexity. This differential planetary gear reducer uses a series combination of two planetary gear reduction mechanisms. The second planetary gear 31 meshes with the differential gear sleeve 5, and a speed difference exists between them, creating relative motion. Utilizing this speed difference, the rotational speed of the planetary gear support in the second-stage planetary gear reduction mechanism 3 is significantly reduced. This not only meets different speed reduction requirements but also significantly reduces the rotational speed of the output shaft 6 while maintaining high-speed rotation of the input shaft, adapting to a wider range of application scenarios.

[0024] like Figure 1 As shown, a differential planetary gear reducer includes a housing 1, a first-stage planetary gear reduction mechanism 2, and a second-stage planetary gear reduction mechanism 3. (As shown...) Figure 1 Combination Figure 2 As shown, a differential gear shaft 4 is provided inside the housing 1. The differential gear shaft 4 is installed inside the housing 1 through bearings. A first meshing part 41 and a second meshing part 42 are provided on the differential gear shaft 4.

[0025] like Figure 2 As shown, a differential gear sleeve 5 is provided between the first-stage planetary gear reduction mechanism 2 and the second-stage planetary gear reduction mechanism 3. The planetary gear support of the second-stage planetary gear reduction mechanism 3 is provided with an output end for connecting the output shaft 6. The differential gear sleeve 5 is provided with a first internal gear ring 51 and a second internal gear ring 52. The first internal gear ring 51 meshes with the first planetary gear 21 of the first-stage planetary gear reduction mechanism 2. The second internal gear ring 52 meshes with the second planetary gear 31 of the second-stage planetary gear reduction mechanism 3.

[0026] In this design, the number of teeth on the first internal gear ring 51 of the differential gear sleeve 5 is defined as Z1, the number of teeth on the second internal gear ring 52 is defined as Z1', the number of teeth on the first meshing part 41 of the differential gear shaft 4 is defined as Z3, the number of teeth on the second meshing part 42 is defined as Z5, and the actual reduction ratio that the planetary gear reducer can achieve is i. 实际 ;

[0027]

[0028] The design of differential gear shaft and differential gear sleeve effectively reduces the loss in the transmission process. Compared with the traditional multi-stage planetary gear transmission method, it reduces energy loss and improves the overall transmission efficiency. Through the design of the two-stage planetary gear reduction mechanism, the reduction device can maintain a high load-bearing capacity while providing a high reduction ratio.

[0029] Traditional planetary gear reducers typically offer a reduction ratio of 100:1. For example, the reduction ratio of a single-stage planetary gear reducer is usually between 3:1 and 10:1; the reduction ratio of a two-stage planetary gear reducer can usually reach around 30:1; and the reduction ratio of a three-stage or more planetary gear reducer can usually reach 100:1 or even higher.

[0030] Compared to traditional planetary gear reducers, the differential planetary gear reducer proposed in this embodiment utilizes a series combination of two-stage planetary gear reduction mechanisms. The second planetary gear meshes with the differential gear sleeve, creating a speed difference between them and resulting in relative motion. This speed difference significantly reduces the speed of the planetary gear support in the second-stage planetary gear reduction mechanism. Furthermore, through the rational design of the number of teeth on the differential gear shaft and differential gear sleeve, a large reduction ratio is achieved. For example, the reduction ratio range of the reduction device is 3000:1-5000:1. This not only meets different reduction requirements but also significantly reduces the speed of the output shaft while maintaining high-speed rotation of the input shaft, adapting to a wider range of application scenarios.

[0031] The differential planetary gear reducer proposed in this embodiment differs from the traditional planetary gear reducer in its reduction principle. Therefore, the calculation method for the reduction ratio of this reducer also differs from that of the traditional planetary gear reducer. The following is a derivation of the reduction ratio calculation and the design of the number of teeth for the differential gear shaft and differential gear sleeve.

[0032] by Figure 2 Taking the reduction gear shown as an example, the number of teeth of the first internal gear ring of the differential gear sleeve is defined as Z1, the number of teeth of the second internal gear ring is defined as Z1', the number of teeth of the differential gear shaft in the first meshing part is Z3, and the number of teeth in the second meshing part is Z5.

[0033] Based on the deceleration principle of the reduction device, the first planetary gear rotates under the drive of the differential gear shaft, causing the differential gear sleeve to rotate around the axis of the differential gear shaft. The second planetary gear rotates under the drive of the differential gear shaft and revolves around the axis of the differential gear shaft. During this process, the second planetary gear meshes with the differential gear sleeve, and there is a speed difference between the two, forming relative motion. By utilizing this speed difference, the speed of the planetary gear support of the two-stage planetary gear reduction mechanism is greatly reduced.

[0034] From the deceleration principle of the above-mentioned deceleration device, we can see that:

[0035]

[0036] Where i is the reduction ratio of the reduction gear, and n 输入 N is the input speed of the motor. 输出 This refers to the output speed of the speed reduction device.

[0037] Since the second planetary gear meshes with the differential sleeve, there is a speed difference between them, resulting in relative motion. Therefore, the output speed is the speed difference between the revolution speed of the second planetary gear and the speed of the differential sleeve, that is:

[0038]

[0039] Where i1 is the reduction ratio of the first-stage planetary gear reduction mechanism, and i2 is the reduction ratio of the second-stage planetary gear reduction mechanism.

[0040] From the above, we can see that:

[0041]

[0042] The reduction ratio i of the deceleration device derived above is the theoretically calculated reduction ratio. In actual design, the actual reduction ratio of the deceleration device will be smaller than the theoretically calculated result. Therefore, in the design, the reduction ratio i will be compensated, that is:

[0043] i 实际 =ia

[0044] Among them, i 实际 Let be the actual reduction ratio that the reduction device can achieve, i be the reduction ratio of the reduction device in the above derivation process, and a be the fitting compensation value of the reduction ratio based on the actual test data.

[0045]

[0046] Therefore, the actual reduction ratio that the reduction device can achieve is:

[0047]

[0048] Further substitutions are made for the reduction ratio i1 of the first-stage planetary gear reducer and the reduction ratio i2 of the second-stage planetary gear reducer in the above formula.

[0049] Both i1 and i2 can be approximated as follows:

[0050]

[0051] Substitute the expressions for i1 and i2 above into

[0052]

[0053] therefore,

[0054]

[0055] As shown in the table below:

[0056] <![CDATA[Z1]]> <![CDATA[Z3]]> <![CDATA[Z1]]> <![CDATA[Z5]]> <![CDATA[i 实际 ]]> 300 12 299 12 7775 32 8 32 9 41 200 5 199 5 8160 300 17 299 17 5576.471

[0057] like Figure 2 As shown, the first-stage planetary gear reduction mechanism 2 includes a first planetary gear 21 and a first planetary gear carrier 22. The first planetary gear carrier 22 is mounted on the first end of the differential gear shaft 4 via bearings. A first rotating shaft 23 for supporting the first planetary gear 21 is provided on the first planetary gear carrier 22. The first planetary gear 21 is mounted on the first rotating shaft 23. The first planetary gear 21 meshes with the first meshing part 41 of the differential gear shaft 4.

[0058] In this way, by directly mounting the first planetary gear 21 onto the first rotating shaft 23 and meshing it with the first meshing part 41 of the differential gear shaft 4, intermediate transmission links are reduced, energy loss is minimized, and transmission efficiency is improved. The first planetary gear support 22 is mounted on the first end of the differential gear shaft 4 via bearings, providing stable support and ensuring the stability and precision of each component during high-speed operation, reducing vibration and noise, and improving the overall stability of the device. The first planetary gear support 22, mounted on the differential gear shaft 4 via bearings, can evenly distribute the load, reduce the pressure on individual gears and bearings, and improve load-bearing capacity and service life.

[0059] The first planetary gear 21 meshes precisely with the first meshing part 41 of the differential gear shaft 4, ensuring the accuracy and consistency of the transmission ratio, thereby achieving a more precise reduction effect. Furthermore, the use of bearings and a reasonable support design reduce wear and mechanical fatigue, improving the operational reliability and lifespan of the device, reducing downtime due to mechanical failures, and increasing production efficiency. The compact design allows the single-stage planetary gear reduction mechanism 2 to occupy less space, making it suitable for use in space-constrained environments and improving the adaptability and flexibility of the device.

[0060] Compared to the first-stage planetary gear reduction mechanism 2, the second-stage planetary gear reduction mechanism 3 has a similar structure. For example... Figure 2 As shown, the two-stage planetary gear reduction mechanism 3 includes a second planetary gear 31 and a second planetary gear support 32. The second planetary gear support 32 is mounted on the second end of the differential gear shaft 4 via a bearing. A second rotating shaft 33 is provided on the second planetary gear support 32 to support the second planetary gear 31. The second planetary gear 31 is mounted on the second rotating shaft 33 and meshes with the second meshing part 42 of the differential gear shaft 4.

[0061] Similarly, the similar structural layout of the two-stage planetary gear reducer 3 and the one-stage planetary gear reducer 2 brings corresponding benefits. The modular design makes the two-stage planetary gear system easier to replace and maintain, simplifying the maintenance process, reducing maintenance cycles and costs, and improving equipment maintainability. The compact two-stage planetary gear design allows the entire reduction device to provide more efficient reduction while occupying less space, making it suitable for space-constrained industrial applications and improving the adaptability and flexibility of the device. By improving transmission efficiency, increasing load-bearing capacity, and reducing maintenance requirements, the overall operating cost of the equipment is reduced, making the two-stage planetary gear reducer more cost-effective in long-term use.

[0062] For example, both the first rotating shaft 23 and the second rotating shaft 33 are pins. The first planetary gear 21 is mounted on the first planetary gear carrier 22 via a pin. The second planetary gear 31 is mounted on the second planetary gear carrier 32 via a pin, and a retaining ring 7 is provided at the end of the pin. This arrangement simplifies the installation and disassembly process of the planetary gears by using pins as the rotating shafts, reduces the complexity of assembly and maintenance, and saves time and labor costs. The pin design provides a firm axial fixation, reduces displacement and wobble during gear operation, and ensures structural stability and smooth operation. Furthermore, the mating design of the pin and the retaining ring 7 reduces friction between the gear and the carrier, reduces wear, and improves the durability and service life of the entire device.

[0063] In addition, the precise fit between the pin and the retaining ring 7 ensures accurate gear positioning and stable rotation, improving the precision and consistency of the transmission system, making it suitable for applications requiring high precision. The pin structure can distribute the load more evenly, reduce local stress concentration, enhance the load-bearing capacity of the entire planetary gear reduction mechanism, and adapt to higher load working conditions.

[0064] To further reduce the assembly difficulty of the reduction gear, the output shaft 6 is connected to the output end of the second planetary gear support 32 via fasteners. This not only simplifies the installation and maintenance process but also enhances the reliability and strength of the connection, improves transmission accuracy, reduces vibration and noise, and enhances the overall safety and cost-effectiveness of the equipment.

[0065] According to some preferred embodiments of this utility model, the end of the differential gear shaft 4 is provided with a connecting flange for mounting a power motor. The connecting flange provides a standardized interface, making the installation process of the power motor simpler and faster, reducing installation time and labor. Furthermore, the connecting flange provides strong mechanical fixation, ensuring a stable and reliable connection between the differential gear shaft 4 and the power motor, capable of withstanding large torques and loads. The flange design can evenly distribute mechanical stress, reducing stress concentration at the connection between the differential gear shaft 4 and the motor, and extending the service life of the components. Through precise flange alignment, the transmission efficiency between the differential gear shaft 4 and the power motor is improved, transmission losses are reduced, and the overall system performance is enhanced.

[0066] The differential planetary gear reducer proposed in this embodiment has wide applications and can be widely used in various industries, including but not limited to food processing equipment, crane equipment, robot joints, etc.

[0067] When using the differential planetary gear reducer proposed in this embodiment of the invention, the following steps are included:

[0068] The main shaft of the power motor transmits power to the housing 1 through the differential gear shaft 4. The first meshing part 41 and the second meshing part 42 on the differential gear shaft 4 drive the first-stage planetary gear reduction mechanism 2 and the second-stage planetary gear reduction mechanism 3 to rotate synchronously.

[0069] The first planetary gear 21 rotates under the drive of the differential gear shaft 4, causing the differential gear sleeve 5 to rotate around the axis of the differential gear shaft 4. The second planetary gear 31 rotates under the drive of the differential gear shaft 4 and revolves around the axis of the differential gear shaft 4. During this process, the second planetary gear 31 meshes with the differential gear sleeve 5, and there is a speed difference between the two, forming relative motion. By utilizing this speed difference, the speed of the planetary gear support of the second-stage planetary gear reduction mechanism 3 is greatly reduced.

[0070] The planetary gear support of the secondary planetary gear reduction mechanism 3 transmits the reduced rotational motion to the output end, which is connected to the output shaft 6, thereby completing the reduction of the power motor.

[0071] This utility model is not limited to the specific technical solutions described in the above embodiments. Besides the above embodiments, this utility model may have other implementation methods. For those skilled in the art, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A differential planetary gear reducer, characterized in that, It includes a housing, a first-stage planetary gear reduction mechanism, and a second-stage planetary gear reduction mechanism; The housing is provided with a differential gear shaft for synchronously driving the first-stage planetary gear reduction mechanism and the second-stage planetary gear reduction mechanism. The differential gear shaft is mounted in the housing via bearings and is provided with a first meshing part and a second meshing part. A differential gear sleeve is provided between the first-stage planetary gear reduction mechanism and the second-stage planetary gear reduction mechanism. The planetary gear support of the second-stage planetary gear reduction mechanism is provided with an output end for connecting the output shaft. The differential gear sleeve is provided with a first internal gear ring and a second internal gear ring. The first internal gear ring meshes with the first planetary gear of the first-stage planetary gear reduction mechanism, and the second internal gear ring meshes with the second planetary gear in the second-stage planetary gear reduction mechanism.

2. The differential planetary gear reducer according to claim 1, characterized in that, The first-stage planetary gear reduction mechanism includes a first planetary gear and a first planetary gear support. The first planetary gear support is mounted on the first end of the differential gear shaft via a bearing. The first planetary gear support is provided with a first rotating shaft for supporting the first planetary gear. The first planetary gear is mounted on the first rotating shaft and meshes with the first meshing part of the differential gear shaft.

3. The differential planetary gear reducer according to claim 2, characterized in that, The two-stage planetary gear reduction mechanism includes a second planetary gear and a second planetary gear support. The second planetary gear support is mounted on the second end of the differential gear shaft via a bearing. A second rotating shaft for supporting the second planetary gear is provided on the second planetary gear support. The second planetary gear is mounted on the second rotating shaft and meshes with the second meshing part of the differential gear shaft.

4. The differential planetary gear reducer according to claim 3, characterized in that, Both the first and second rotating shafts are pins. The first planetary gear is mounted on the first planetary gear support via the pin, and the second planetary gear is mounted on the second planetary gear support via the pin. A retaining ring is provided at the end of each pin.

5. The differential planetary gear reducer according to claim 3, characterized in that, The output shaft is connected to the output end of the second planetary gear carrier via fasteners.

6. The differential planetary gear reducer according to claim 1, characterized in that, The end of the differential gear shaft is provided with a connecting flange for mounting a power motor.

7. The differential planetary gear reducer according to claim 1, characterized in that, The reduction ratio range of the differential planetary gear reducer is 3000:1-5000:1.

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