High-transmission-ratio sine tooth RV speed reducer

Abstract

The invention discloses a high-transmission-ratio sine gear RV reducer, which belongs to the technical field of reducers and comprises a left planet carrier, a right planet carrier, an inner gear ring, planet gears, eccentric shafts, chord gears, an input shaft and an output end cover. A chord line tooth profile is arranged at the shaft end on one side of the input shaft; the input shaft penetrates through inner holes of the right planet carrier and the left planet carrier to be meshed with the first-stage transmission chord line wheel. The chord line wheel drives the eccentric shaft to rotate, and then the eccentric shaft drives the planet wheel to rotate; the planet wheel revolves around the center of the inner gear ring and simultaneously rotates to realize transmission; second-stage transmission is small-tooth-difference planetary gear transmission, and inner teeth of the gear ring and outer teeth of the planetary gear are both sine tooth profiles; the first-stage transmission is chord line fixed-axis cylindrical gear transmission, and the first-stage transmission sun gear and the first-stage transmission planet gear are both sine tooth profiles. Compared with a traditional RV speed reducer, the transmission ratio adjusting limitation of an involute tooth profile and a cycloidal pin wheel is exceeded, the transmission ratio is further increased to 1.5-4 times, and the bearing capacity is improved.

Description

Technical Field

[0001] This invention relates to the field of speed reducer technology, and in particular to a high transmission ratio sinusoidal gear RV speed reducer. Background Technology

[0002] As a core transmission component of high-end equipment, the performance of the RV reducer directly determines the equipment's motion accuracy, load-bearing capacity, and service life. Existing RV reducers generally adopt a combined configuration of "involute fixed-axis cylindrical gear transmission + cycloidal pinwheel transmission," with the transmission ratio primarily determined by the difference between the number of teeth on the cycloidal pinwheel and the number of teeth on the pinwheel, as well as the transmission ratio of the first-stage involute gear.

[0003] However, this traditional configuration has significant limitations: on the one hand, the number of pin teeth in a cycloidal pinwheel drive is limited by the structural dimensions and material strength of the internal gear ring, making it impossible to further increase the transmission ratio by increasing the number of pin teeth; on the other hand, the meshing characteristics of the involute tooth profile result in a narrow transmission ratio adjustment range for the first stage, and the involute tooth profile is prone to impact vibration during meshing, affecting transmission smoothness. Simultaneously, the abrupt change in local curvature of the cycloidal tooth profile leads to uneven distribution of contact stress in the gear pair, limiting the improvement of load-bearing capacity.

[0004] With the development of industrial robots towards heavier loads and higher precision, and the demand for compact transmission systems in aerospace equipment, the problems of traditional RV reducers, such as insufficient transmission ratio (usually the maximum transmission ratio does not exceed 220), limited load-bearing capacity, and large operating vibration, are becoming increasingly prominent and can no longer meet the requirements of high-end equipment. Therefore, there is an urgent need to develop an RV reducer that can break through the constraints of traditional tooth profile design and has a high transmission ratio, high load-bearing capacity, and high operational stability. Summary of the Invention

[0005] To address the problems of existing RV reducers, this invention provides a high-ratio sinusoidal gear RV reducer. The first-stage transmission is a chordal fixed-axis cylindrical gear transmission, and the second-stage transmission is a planetary gear transmission with a small tooth difference. The external teeth of the planetary gears, the internal teeth of the internal gear ring, the sun gear (on one side of the input shaft), and the planetary gears (chordal gears) of the first-stage transmission are designed with sinusoidal tooth profiles, expanding the design space for the RV reducer's transmission ratio. The transmission ratio in the second-stage transmission can be increased to [a higher value]. The transmission ratio in a single-stage transmission can be increased by times. The RV reducer gear based on continuous sinusoidal teeth proposed in this invention provides smooth and continuous transmission, stable operation, low impact vibration, and improved load-bearing capacity during meshing and disengagement; the transmission ratio can be increased. It is twice as fast as other applications, making it particularly suitable for high-speed, heavy-duty, and size-constrained applications.

[0006] The technical solution adopted by the present invention for a high transmission ratio sinusoidal gear RV reducer is as follows:

[0007] A high transmission ratio sinusoidal gear RV reducer includes a planetary carrier assembly, an internal gear ring, planetary gears, an eccentric shaft, a chord wheel, an input shaft, and an output end cover. The planetary carrier assembly rotatably engages with the internal gear ring, and the output end cover is fixedly connected to the planetary carrier assembly, forming the power output end. The internal gear ring is a fixed end. The input shaft passes through the planetary carrier assembly and meshes with the chord wheel for transmission. The chord wheel is driven by the eccentric shaft, which rotatably engages with the planetary gears, causing the planetary gears to revolve around the center of the internal gear ring and rotate on their own axis. The meshing parts of the input shaft and the chord wheel, and the meshing parts of the planetary gears and the internal gear ring, both employ continuous sinusoidal tooth profiles, forming a two-stage composite transmission configuration. The geometric characteristics of the sinusoidal tooth profile expand the design space for the transmission ratio.

[0008] A further improvement of the technical solution of the present invention is that: in the two-stage composite transmission configuration, the first stage transmission is a chordal fixed-axis cylindrical gear transmission, the meshing part of the input shaft constitutes the first stage transmission sun gear, and the chordal gear constitutes the first stage transmission planet gear, and the teeth of both are sinusoidal tooth profiles.

[0009] A further improvement of the technical solution of the present invention is that: in the two-stage composite transmission configuration, the second stage transmission is a chordal tooth planetary gear transmission with small tooth difference, and the outer teeth of the planetary gear and the inner teeth of the inner gear ring are both sinusoidal tooth profiles, with multiple tooth surfaces meshing smoothly at the same time.

[0010] A further improvement of the technical solution of the present invention lies in the parametric equation of the curve corresponding to the continuous sinusoidal tooth profile in the Cartesian coordinate system. for:

[0011]

[0012] in, The number of teeth is the sine tooth profile. The radius of the pitch circle of the sinusoidal tooth profile; The coordinates of the sinusoidal tooth profile angle; This is the tooth height coefficient.

[0013] A further improvement of the technical solution of the present invention is that: the planetary carrier assembly includes a left planetary carrier and a right planetary carrier, the left planetary carrier and the right planetary carrier are fixedly connected by screws evenly distributed in the circumference, and the two are symmetrically arranged at both ends of the internal gear ring; the shoulder parts of the left planetary carrier and the right planetary carrier are engaged with the inner hole of the internal gear ring by a first deep groove ball bearing, so as to realize the radial positioning and rotational support of the planetary carrier assembly relative to the internal gear ring.

[0014] A further improvement of the technical solution of the present invention is that: the input shaft is provided with a first input shaft segment, a second input shaft segment, and a third input shaft segment in sequence along the axial direction; the first input shaft segment is provided with a keyway structure for connecting with the output shaft of the motor; the third input shaft segment is provided with a sinusoidal tooth profile forming the teeth of the first-stage transmission sun gear; the eccentric shaft is provided with an eccentric first shaft segment, an eccentric second shaft segment, and an eccentric third shaft segment in sequence along the axial direction; the eccentric first shaft segment is provided with a keyway structure; the eccentric second shaft segment is provided with an eccentric distance relative to the eccentric first shaft segment and the eccentric third shaft segment.

[0015] The technological advancements achieved by this invention due to the adoption of the above technical solutions are as follows:

[0016] This invention overcomes the constraints of traditional involute and cycloidal tooth profiles on tooth number matching by unifying the tooth profiles of the first and second stage transmissions into a continuous sinusoidal tooth profile, thereby increasing the first stage transmission ratio to that of traditional transmissions. The second-stage transmission ratio is increased to that of traditional transmissions. The overall transmission ratio can be increased by times, reaching that of a traditional RV reducer. The sine tooth profile has a higher transmission efficiency, which can significantly reduce the overall size of the reducer under the same transmission ratio requirements, thereby reducing the volume of the RV reducer and making it more suitable for applications with limited installation space.

[0017] The sinusoidal tooth profile of this invention is continuous and smooth, which enables multiple tooth surfaces to contact simultaneously during the meshing process of the gear pair, increases the contact area, makes the contact stress distribution more uniform, reduces local stress concentration, and improves the load-bearing capacity of the RV reducer.

[0018] The present invention features a sinusoidal tooth profile with continuous curvature change without abrupt changes, and the gear achieves a gradual transition during the meshing and disengagement stages. This avoids the tooth tip impact of traditional involute tooth profiles and the local curvature abrupt changes of cycloidal tooth profiles, significantly reducing impact vibration during operation, reducing noise, and improving motion accuracy. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view of an RV reducer based on continuous sinusoidal teeth according to the present invention.

[0020] Figure 2 This is a simplified diagram of the transmission motion of an RV reducer based on continuous sinusoidal teeth according to the present invention;

[0021] Figure 3 This is a schematic diagram of the internal gear ring structure of an RV reducer based on continuous sinusoidal teeth according to the present invention;

[0022] Figure 4 This is a schematic diagram of a chord wheel structure for an RV reducer based on continuous sinusoidal teeth according to the present invention;

[0023] Figure 5This is a schematic diagram of the output end cover structure of an RV reducer based on continuous sinusoidal teeth according to the present invention;

[0024] Figure 6 This is a schematic diagram of the left planetary carrier structure of an RV reducer based on continuous sinusoidal teeth according to the present invention;

[0025] Figure 7 This is a schematic diagram of a planetary gear structure for an RV reducer based on continuous sinusoidal teeth according to the present invention;

[0026] Figure 8 This is a schematic diagram of the right planetary carrier structure of an RV reducer based on continuous sinusoidal teeth according to the present invention;

[0027] Figure 9 This is a schematic diagram of the input shaft structure of an RV reducer based on continuous sinusoidal teeth according to the present invention;

[0028] Figure 10 This is a schematic diagram of the eccentric shaft structure of an RV reducer based on continuous sinusoidal teeth according to the present invention.

[0029] In the attached diagram: 1. Internal gear ring; 101. First inner hole; 102. Internal gear; 103. Second inner hole;

[0030] 2. First deep groove ball bearing;

[0031] 3. String wheel; 301. First gear tooth;

[0032] 4. Output end cover; 401. First shaft shoulder;

[0033] 5. Left planetary carrier; 501. Third inner bore; 502. Second shoulder; 503. Third shoulder;

[0034] 6. Planetary gear; 601. First external tooth; 602. Fourth internal hole;

[0035] 7. Right planetary carrier; 701. Fifth inner bore; 702. Fourth shoulder;

[0036] 8. Input axis; 801. Input third axis segment; 802. Input second axis segment; 803. Input first axis segment;

[0037] 9. Eccentric shaft; 901. First eccentric shaft segment; 902. Second eccentric shaft segment; 903. Third eccentric shaft segment;

[0038] 10. Second deep groove ball bearing; 11. Needle roller bearing. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings. In the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concept of this invention.

[0040] like Figure 1 As shown, this embodiment discloses a high transmission ratio sinusoidal gear RV reducer, including a left planet carrier 5, a right planet carrier 7 (the left planet carrier 5 and the right planet carrier 7 together constitute a planet carrier assembly), an internal gear ring 1, planet gears 6, an eccentric shaft 9, a chord wheel 3, an input shaft 8, and an output end cover 4.

[0041] The internal gear ring 1 has a ring structure with internal teeth 102 (sine tooth profile) on its inner wall and three circumferentially evenly distributed mounting lugs integrally formed on its outer peripheral wall. Each mounting lug has an oblong adjustment hole. The internal gear ring 1 is fixed to the motor housing by bolts passing through the oblong adjustment holes, thereby achieving the positioning of the fixed end of the reducer. The two ends of the internal gear ring 1 are respectively provided with a first inner hole 101 and a second inner hole 103 for mounting the first deep groove ball bearing 2.

[0042] Both the left planetary carrier 5 and the right planetary carrier 7 are disc-shaped structures. The left planetary carrier 5 has a third shoulder 503 on one side, and the right planetary carrier 7 has a fourth shoulder 702 on one side. The third shoulder 503 and the fourth shoulder 702 respectively engage with the first inner hole 101 and the second inner hole 103 of the internal gear ring 1 via deep groove ball bearings 2, achieving radial positioning and rotational support of the planetary carrier assembly relative to the internal gear ring 1. The left planetary carrier 5 and the right planetary carrier 7 are fixedly connected by six circumferentially evenly distributed Phillips head countersunk screws to ensure synchronous rotation. The left planetary carrier 5 has three evenly distributed third inner holes 501, and the right planetary carrier 7 has three corresponding fifth inner holes 701 for mounting the second deep groove ball bearing 10.

[0043] The input shaft 8 is provided with a first input shaft section 803, a second input shaft section 802, and a third input shaft section 801 along the axial direction. The first input shaft section 803 has a keyway with a width of 2mm for connecting to the motor output shaft via a flat key. The second input shaft section 802 is a transition section. The outer periphery of the third input shaft section 801 has a sinusoidal tooth profile (the teeth of the first-stage transmission sun gear). The input shaft 8 passes through the center hole of the right planetary carrier 7 and the center hole of the left planetary carrier 5 in sequence. The third input shaft section 801 meshes with the internal teeth of the chord wheel 3.

[0044] The chord wheel 3 is a ring gear with a sinusoidal tooth profile on its first tooth 301. A keyway is provided on one side of the chord wheel 3, which is connected to one end of the eccentric shaft 9 via a flat key. There are two eccentric shafts 9, evenly distributed circumferentially. The eccentric shafts 9 are sequentially provided with an eccentric first shaft section 901, an eccentric second shaft section 902, and an eccentric third shaft section 903 along the axial direction. The eccentric first shaft section 901 and the eccentric third shaft section 903 are respectively installed in the third inner hole 501 of the left planetary carrier 5 and the fifth inner hole 701 of the right planetary carrier 7 via second deep groove ball bearings 10. The eccentric second shaft section 902 is an eccentric section with an eccentricity of 0.4 mm relative to the eccentric first shaft section 901 and the eccentric third shaft section 903, and is engaged with the fourth inner hole 602 of the planetary gear 6 via a needle roller bearing 11.

[0045] The planetary gear 6 has a ring structure, and its first external tooth 601 has a sinusoidal tooth profile. The first external tooth 601 of the planetary gear 6 meshes with the internal tooth 102 of the internal gear ring 1 to realize planetary transmission with small tooth difference.

[0046] The output end cover 4 has a disc-shaped structure with a first shoulder 401 on one side. An annular groove is provided on the first shoulder 401 for installing a nitrile rubber seal to achieve axial sealing. The output end cover 4 is fixedly connected to the left planetary carrier 5 by six circumferentially evenly distributed hexagonal screws. The center of the output end cover 4 has an output shaft hole for connecting with the actuator to transmit torque.

[0047] In this embodiment, the parametric equation of the curve corresponding to the sinusoidal tooth profile in a Cartesian coordinate system for:

[0048]

[0049] in, The number of teeth is the sine tooth profile. The radius of the pitch circle of the sinusoidal tooth profile; The coordinates of the sinusoidal tooth profile angle; This is the tooth height coefficient.

[0050] This embodiment presents an RV reducer based on continuous sinusoidal teeth, with overall dimensions of 58mm outer diameter and 50mm total length. It features two eccentric shafts (9), and its load-bearing capacity is 1.5 times higher than that of traditional RV reducers. The overall transmission ratio range is... The internal gear 102, external gear 601, the teeth of the first-stage transmission sun gear, and the teeth of the first-stage transmission planet gear all have sinusoidal tooth profiles.

[0051] The theoretical parameters of the reducer transmission are shown in Tables 1 and 2 below:

[0052] Table 1 Theoretical parameters of the first-stage transmission structure

[0053] An RV reducer based on continuous sinusoidal teeth has the following overall dimensions: outer diameter 58mm, total length 50mm, two eccentric shafts, and a load-bearing capacity 1.5 times higher than traditional RV reducers. The overall transmission ratio range is... The internal tooth 102, the first external tooth 601, the teeth of the first-stage transmission sun gear, and the teeth of the first-stage transmission planet gear all have sinusoidal tooth profiles.

[0054] The theoretical parameters of the reducer transmission are shown in Tables 1 and 2 below:

[0055] Table 1 Theoretical parameters of the first-stage transmission structure

[0056]

[0057] Table 2 Theoretical parameters of the two-stage transmission structure

[0058]

[0059] The working principle of this embodiment is as follows: the motor drives the input shaft 8 to rotate through the key, and the eccentric third shaft segment 903 meshes with the first-stage transmission chord wheel 3 to realize the first-stage reduction transmission; the chord wheel 3 drives the eccentric shaft 9 to rotate through the keyway, and the eccentric shaft 9 drives the planetary gear 6 to rotate. The planetary gear 6 meshes with the internal gear ring 1. At the same time, the planetary gear 6 drives the left planetary carrier 5 and the right planetary carrier 7 to rotate. The left planetary carrier 5 and the right planetary carrier 7 are fixed by multiple screws. The left planetary carrier 5 is fixed to the output end cover 4 by multiple screws, so that the output end cover 4 outputs torque.

[0060] In the above embodiments, a high transmission ratio sinusoidal tooth RV reducer is provided. This invention overcomes the constraints of traditional involute and cycloidal tooth profiles on tooth number matching by uniformly designing the tooth profiles of the first and second stages of transmission as continuous sinusoidal tooth profiles. The first-stage transmission ratio is increased to that of traditional… The second-stage transmission ratio is increased to that of traditional transmissions. The overall transmission ratio can be increased by times, reaching that of a traditional RV reducer. The sine tooth profile of this invention offers higher transmission efficiency under the same transmission ratio requirements, significantly reducing the overall size of the reducer and thus decreasing the volume of the RV reducer, making it more suitable for applications with limited installation space. The continuous and smooth curve of the sine tooth profile allows for simultaneous contact of multiple tooth surfaces during gear meshing, increasing the contact area, resulting in a more uniform distribution of contact stress, reducing local stress concentration, and enhancing the load-bearing capacity of the RV reducer. Furthermore, the continuous and abrupt curvature change of the sine tooth profile allows for a gradual transition during gear engagement and disengagement, avoiding the impact of tooth tip insertion and the abrupt curvature changes of traditional involute tooth profiles. This significantly reduces impact vibration during operation, lowers noise, and improves motion accuracy.

[0061] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the concept and scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the inventive concept should fall within the protection scope of the present invention. All technical contents for which protection is sought in this invention are fully described in the claims.

Claims

1. A high transmission ratio sinusoidal gear RV reducer, characterized in that: The system includes a planetary carrier assembly, an internal gear ring (1), planetary gears (6), an eccentric shaft (9), a chord wheel (3), an input shaft (8), and an output end cover (4). The planetary carrier assembly rotates with the internal gear ring (1), and the output end cover (4) is fixedly connected to the planetary carrier assembly to form a power output end. The internal gear ring (1) is a fixed end. The input shaft (8) passes through the planetary carrier assembly and meshes with the chord wheel (3) for transmission. The chord wheel (3) is driven by the eccentric shaft (9). The eccentric shaft (9) rotates with the planetary gears (6) and drives the planetary gears (6) to revolve around the center of the internal gear ring (1) and rotate on their own axis. The meshing parts of the input shaft (8) and the chord wheel (3) and the meshing parts of the planetary gears (6) and the internal gear ring (1) all adopt continuous sinusoidal tooth profiles to form a two-stage composite transmission configuration. The transmission ratio design space is expanded by the geometric characteristics of the sinusoidal tooth profile.

2. The high transmission ratio sinusoidal gear RV reducer according to claim 1, characterized in that: In the two-stage composite transmission configuration, the first stage transmission is a chordal fixed-axis cylindrical gear transmission. The input shaft (8) and the corresponding meshing part constitute the first stage transmission sun gear, and the chordal gear (3) constitutes the first stage transmission planet gear (6). The teeth of both gears have a sinusoidal tooth profile.

3. The high transmission ratio sinusoidal gear RV reducer according to claim 1, characterized in that: In the two-stage composite transmission configuration, the second stage transmission is a chordal tooth planetary gear transmission with small tooth difference. The external teeth of the planetary gear (6) and the internal teeth (102) of the internal gear ring (1) are both sinusoidal tooth profiles, and multiple tooth surfaces mesh smoothly at the same time.

4. A high transmission ratio sinusoidal gear RV reducer according to claim 1, characterized in that, The parametric equation of the curve corresponding to the continuous sinusoidal tooth profile in a Cartesian coordinate system for: ； in, The number of teeth is the sine tooth profile. The radius of the pitch circle of the sinusoidal tooth profile; The coordinates of the sinusoidal tooth profile angle; This is the tooth height coefficient.

5. A high transmission ratio sinusoidal gear RV reducer according to claim 1, characterized in that: The planetary carrier assembly includes a left planetary carrier (5) and a right planetary carrier (7). The left planetary carrier (5) and the right planetary carrier (7) are fixedly connected by screws evenly distributed in the circumference. They are symmetrically arranged at both ends of the internal gear ring (1). The shoulder parts of the left planetary carrier (5) and the right planetary carrier (7) are engaged with the inner hole of the internal gear ring (1) through a first deep groove ball bearing (2) to achieve radial positioning and rotational support of the planetary carrier assembly relative to the internal gear ring (1).

6. A high transmission ratio sinusoidal gear RV reducer according to claim 1, characterized in that: The input shaft (8) is provided with an input first shaft segment (803), an input second shaft segment (802) and an input third shaft segment (801) in sequence along the axial direction. The input first shaft segment (803) is provided with a keyway structure for connecting with the motor output shaft, and the input third shaft segment (801) is provided with a sine tooth profile to form the teeth of the first-stage transmission sun gear. The eccentric shaft (9) is provided with an eccentric first shaft segment (901), an eccentric second shaft segment (902) and an eccentric third shaft segment (903) in sequence along the axial direction. The eccentric first shaft segment (901) is provided with a keyway structure, and the eccentric second shaft segment (902) is provided with an eccentric distance relative to the eccentric first shaft segment (901) and the eccentric third shaft segment (903).

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