New energy planetary gear reducer

Abstract

The application discloses a new energy planetary gear reducer, which comprises a first planetary row, a second planetary row, a shared ring gear and a shell. The shared ring gear is slidably arranged in the shell in an axial direction, and an inner circumferential surface of the shared ring gear is divided into a first helical tooth area and a second helical tooth area with opposite rotation directions, and the first helical tooth area and the second helical tooth area are respectively engaged with a first planetary gear of the first planetary row and a second planetary gear of the second planetary row to realize self-balancing of an axial force in a steady state. An annular sealing cavity filled with a magneto-rheological fluid is arranged between the shared ring gear and the shell, and an electromagnetic coil is integrated on the shell and used for dynamically adjusting a shear strength of the magneto-rheological fluid. The application cooperates the intelligent damping of the magneto-rheological fluid and the rotation direction design of the shared ring gear, and simultaneously considers load balance, impact resistance and transmission stability, so that the reliability and durability of the reducer under complex working conditions are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of planetary gear reducer technology, and specifically relates to a new energy planetary gear reducer. Background Technology

[0002] In the electric drive system of pure electric vehicles, in order to balance high reduction ratio and compact layout, a double-row planetary gear reducer is often used. The planetary gears are mostly helical gears. However, helical gear meshing will generate significant axial force. Traditional solutions need to rely on thrust bearings or housing structures to bear this load, which leads to an increase in the axial dimension of the system and an increase in friction loss.

[0003] To reduce net axial load, existing technologies have attempted to use a shared ring gear with oppositely helical tooth zones at the front and rear, allowing the two planetary gear sets to apply opposite axial forces to the ring gear under steady-state conditions, achieving internal self-balancing. While this method effectively reduces steady-state axial load, it still faces significant challenges in actual vehicle operation: when the output end encounters transient load disturbances such as road impacts, rapid acceleration, or emergency braking, the difference in rotational inertia between the first and second planetary carriers causes a temporary imbalance in the axial forces exerted by the two planetary gear sets on the shared ring gear, leading to uncontrolled micro-displacement or high-frequency oscillations of the ring gear. Without an effective damping mechanism, such dynamic responses can easily cause meshing impacts, increased noise, and even localized tooth surface fatigue.

[0004] Currently, floating gear rings mostly rely on passive components such as springs and rubber pads to provide the restoring force. Their damping characteristics are fixed and cannot be dynamically adjusted according to the working conditions. This makes it difficult to suppress overshoot in low-damping conditions, while high-damping conditions limit the necessary micro-movements of the gear ring in steady state to accommodate manufacturing errors or thermal deformation.

[0005] Therefore, there is an urgent need for an intelligent control mechanism that allows adaptive micro-motion in steady state and actively suppresses overshoot in transient state, so as to give full play to the advantages of the axial force self-balancing structure and improve the load balancing capability, impact resistance and transmission smoothness of the reducer under complex working conditions. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution.

[0007] A new energy planetary gear reducer includes a housing, a first planetary gear set, and a second planetary gear set. The first planetary gear set includes a first sun gear, first planetary gears, and a first planetary carrier. The second planetary gear set includes a second sun gear, second planetary gears, and a second planetary carrier. Furthermore, the reducer includes a common gear ring slidably mounted axially within the housing. The internal teeth of the common gear ring are divided axially into a first helical tooth region and a second helical tooth region with opposite directions of rotation, respectively meshing with the first planetary gear and the second planetary gear.

[0008] At least one annular sealing cavity is provided between the outer peripheral surface of the common gear ring and the inner wall of the housing, and the annular sealing cavity is filled with magnetorheological fluid. An electromagnetic coil is integrated on the housing, and the electromagnetic coil is configured to generate a controllable magnetic field in the annular sealing cavity when energized, so as to adjust the shear strength of the magnetorheological fluid, thereby dynamically controlling the axial floating damping of the common gear ring.

[0009] Furthermore, when the electromagnetic coil is de-energized, the magnetorheological fluid is in a low-viscosity state, and the common gear ring floats freely axially under the torque difference between the front and rear planetary gear sets, achieving passive load balancing; when the electromagnetic coil is energized, the viscosity of the magnetorheological fluid increases, suppressing the overshoot displacement of the common gear ring and achieving active damping control.

[0010] Furthermore, the common gear ring is provided with elastic reset elements at both ends of its axial direction. The elastic reset elements are one of disc springs, wave springs, or rubber elastic pads, and are used to provide a center positioning force.

[0011] Furthermore, the elastic reset element is a rubber elastic pad, and an oil-retaining sponge is fitted on the side facing the common gear ring. An oil-retaining groove for accommodating the oil-retaining sponge is provided on the end face of the common gear ring. A through groove that radially extends to the first oblique tooth area or the second oblique tooth area is provided on the side of the oil-retaining groove near the center of the common gear ring.

[0012] When the shared gear ring moves axially, the oil reservoir sponge at one end is squeezed by the corresponding rubber elastic pad, and the squeezed-out lubricating oil flows through the through groove into the meshing gap between the corresponding planetary gear and the helical gear area; the oil reservoir sponge at the other end absorbs lubricating oil due to the reduced pressure.

[0013] Furthermore, the annular sealing cavity is formed by the outer circle of the common toothed ring, the inner wall of the housing, and the sealing rings on both sides, and the sealing rings are made of fluororubber.

[0014] Furthermore, a limiting pin is provided on the inner wall of the housing, and an axially extending limiting groove is provided on the outer circumferential surface of the common gear ring. The length of the limiting groove is 0.2 mm to 1.5 mm and does not exceed 10% of the tooth width of any planetary gear.

[0015] Furthermore, the magnetorheological fluid is a silicone oil-based magnetorheological fluid with an operating temperature range of -40℃ to +150℃, a zero-field viscosity of 0.1 to 0.5 Pa·s, and a continuously adjustable saturated shear yield strength of 0 to 80 kPa.

[0016] Compared with existing technologies, this application has the following beneficial technical effects: It adopts a shared gear ring with opposite internal tooth rotation directions, and integrates a magnetorheological fluid damping cavity and an electromagnetic coil between the shared gear ring and the housing, achieving intelligent floating control. Specifically, during steady-state operation, the axial force on the shared gear ring is self-balanced, the magnetorheological fluid maintains low damping, and slight floating is allowed to accommodate manufacturing errors. When the output end encounters an impact or a sudden load change, the inertial difference causes an instantaneous axial force imbalance, the shared gear ring generates a slight displacement to redistribute the meshing load, and at the same time, the electromagnetic coil is energized to increase the damping of the magnetorheological fluid, effectively suppressing overshoot oscillations, and balancing load balance, impact resistance, and transmission smoothness. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of a novel planetary gear reducer.

[0018] Figure 2 This is a half-sectional view of a new type of planetary gear reducer.

[0019] Figure 3 for Figure 2 A magnified view of a portion of point A in the middle.

[0020] The following is an explanation of the reference numerals in the attached figures:

[0021] 10. Housing; 11. Electromagnetic coil; 12. Elastic reset element; 12a. Rubber elastic pad; 13. Oil reservoir sponge; 14. Guide pin;

[0022] 20. Shared toothed ring; 21. Annular sealing cavity; 22. First helical tooth area; 23. Second helical tooth area; 24. Sealing ring; 25. Limiting groove; 26. Through groove;

[0023] 30. First planetary gear set; 31. Input shaft; 32. First sun gear; 33. First planetary gear set; 34. First planet carrier;

[0024] 40. Second planetary gear set; 41. Output shaft; 42. Second sun gear; 43. Second planetary gear set; 44. Second planetary carrier. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0026] In the following embodiments, the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0027] In the description of this invention, it should be understood that terms such as center, longitudinal, transverse, length, width, thickness, upper, lower, front, rear, left, right, vertical, horizontal, top, bottom, inner, outer, clockwise, counterclockwise, etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the description of this invention; therefore, they should not be construed as limiting this invention. Furthermore, terms such as first, second, etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features shown. In the description of this invention, unless otherwise expressly specified and limited, terms such as installation, connection, linking, etc., should be interpreted broadly, and those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0028] Reference Figures 1 to 3 This embodiment provides a novel planetary gear reducer for use in a new energy vehicle drive system. The reducer mainly includes a housing 10, a first planetary gear set 30, and a second planetary gear set 40. The housing 10 is cast from a high-strength, lightweight alloy and has an internal mounting chamber. The first planetary gear set 30 and the second planetary gear set 40 are arranged side-by-side along the axial direction within the housing 10. The first planetary gear set 30 includes a first sun gear 32 connected to an input shaft 31, a plurality of circumferentially distributed first planetary gears 33, and a first planet carrier 34 supporting the first planetary gears 33. The second planetary gear set 40 includes a second sun gear 42 connected to the first planet carrier 34, a plurality of circumferentially distributed second planetary gears 43, and a second planet carrier 44 supporting the second planetary gears 43. An output shaft 41 for outputting power is mounted on the second planet carrier 44.

[0029] Crucially, the reducer also includes a common gear ring 20, which is axially slidably mounted within the housing 10. The common gear ring 20 is a one-piece structure, with its inner circumferential surface divided axially into a first helical gear section 22 and a second helical gear section 23, with opposite helical directions. The first helical gear section 22 meshes with the first planetary gear 33, and the second helical gear section 23 meshes with the second planetary gear 43. Due to the helical gear design and opposite helical directions, during steady-state operation, the first planetary gear set 30 and the second planetary gear set 40 apply opposite axial forces to the common gear ring 20, achieving internal self-balancing and significantly reducing the net axial load of the system.

[0030] An annular sealing cavity 21 is provided between the outer cylindrical surface of the common toothed ring 20 and the inner wall of the housing 10. This annular sealing cavity 21 is formed by the groove on the outer circumference of the common toothed ring 20, the inner wall of the housing 10, and fluororubber sealing rings 24 installed on both sides of the groove, creating a closed space. The annular sealing cavity 21 is filled with magnetorheological fluid. In this embodiment, a silicone oil-based magnetorheological fluid is used, which has a wide operating temperature range, low viscosity at zero magnetic field, and its shear yield strength can be quickly and continuously adjusted under a magnetic field. Corresponding to the location of the sealing cavity, an electromagnetic coil 11 is integrated and embedded inside the wall of the housing 10. The number of turns in the coil is 150–300 (e.g., 200 turns), the operating voltage is 12V or 48V, and the response frequency is not less than 100 Hz (e.g., 200 Hz).

[0031] To provide a restoring force to the common gear ring 20 towards a central equilibrium position, elastic reset elements 12 are provided at both ends of its axial direction. These elastic reset elements 12 can be disc springs, wave springs, or rubber elastic pads 12a, etc. As a further optimization, when using rubber elastic pads 12a, an adaptive lubrication system can be incorporated: an annular oil reservoir is machined on each end face of the common gear ring 20, and an oil-saturated sponge 13 (such as an open-cell polyurethane material) is placed within the reservoir. The rubber elastic pads 12a press precisely against the oil-saturated sponge 13 during assembly. A radial through-slot is formed on the side of the oil reservoir near the center of the gear ring, extending to the meshing area of ​​the first helical tooth region 22 or the second helical tooth region 23. When the common gear ring 20 moves to the left, the left-side oil-saturated sponge 13 is compressed by the rubber elastic pad 12a, and lubricating oil flows into the left-side meshing area through the through-slot; the right-side oil-saturated sponge 13 absorbs lubricating oil due to pressure release, achieving on-demand lubrication and recycling.

[0032] In addition, to monitor the position of the common gear ring 20 in real time, a non-contact displacement sensor (such as a Hall effect non-contact displacement sensor) is installed on the housing 10, with its probe aligned with a sensing target set on the end face of the common gear ring 20. To prevent the common gear ring 20 from rotating accidentally or displacing excessively, a guide pin 14 is provided on the inner wall of the housing 10, and an axially extending limiting groove 25 is provided on the outer circumferential surface of the common gear ring 20 to cooperate with it. The sliding stroke of the limiting pin in the limiting groove 25 is set to 0.2~1.5mm to ensure that it does not exceed 10% of the tooth width of any planetary gear. This size design can ensure the necessary floating amount and provide mechanical safety limits.

[0033] The working principle of the reducer described in this application is as follows: During normal constant speed driving, the electromagnetic coil 11 is de-energized, the magnetorheological fluid is in a low viscosity state, and the common gear ring 20 can move freely to accommodate manufacturing errors and thermal deformation. When the vehicle passes over a speed bump, brakes suddenly, or encounters a sudden change in road surface, the output shaft 41 is subjected to a reverse impact. Due to inertia, the second planetary carrier 44 lags behind the first planetary carrier 34, resulting in inconsistent instantaneous torques between the two planetary carriers. Under the action of net axial force, the common gear ring 20 generates a slight displacement, realizing the transfer of load to the side with less force. At this time, the vehicle controller activates the electromagnetic coil 11 according to the displacement sensor signal, increases the damping of the magnetorheological fluid, suppresses overshoot of the gear ring, and avoids secondary impact.

[0034] The scope of protection of this invention includes, but is not limited to, the above embodiments. The scope of protection of this invention is defined by the claims. Any substitutions, modifications, or improvements to this technology that are easily conceived by those skilled in the art fall within the scope of protection of this invention.

Claims

1. A new energy planetary gear reducer, comprising a housing (10), a first planetary gear set (30), and a second planetary gear set (40), wherein the first planetary gear set (30) comprises a first sun gear (32), a first planetary gear set (33), and a first planetary carrier set (34), and the second planetary gear set (40) comprises a second sun gear set (42), a second planetary gear set (43), and a second planetary carrier set (44), characterized in that: It also includes a common gear ring (20) slidably mounted in the housing (10) along the axial direction. The internal teeth of the common gear ring (20) are divided into a first helical tooth area (22) and a second helical tooth area (23) with opposite directions of rotation along the axial direction, which mesh with the first planetary gear (33) and the second planetary gear (43) respectively. At least one annular sealing cavity (21) is provided between the outer peripheral surface of the common toothed ring (20) and the inner wall of the housing (10), and the annular sealing cavity (21) is filled with magnetorheological fluid; an electromagnetic coil (11) is integrated on the housing (10), and the electromagnetic coil (11) is configured to generate a controllable magnetic field in the annular sealing cavity (21) when energized, so as to adjust the shear strength of the magnetorheological fluid, thereby dynamically controlling the axial floating damping of the common toothed ring (20).

2. The new energy planetary gear reducer according to claim 1, characterized in that: When the electromagnetic coil (11) is de-energized, the magnetorheological fluid is in a low viscosity state, and the common gear ring (20) floats freely in the axial direction under the torque difference of the front and rear planetary gear sets, thereby achieving passive load balance; when the electromagnetic coil (11) is energized, the viscosity of the magnetorheological fluid increases, suppressing the overshoot displacement of the common gear ring (20), thereby achieving active damping control.

3. The new energy planetary gear reducer according to claim 1, characterized in that: The common toothed ring (20) is provided with elastic reset elements (12) at both ends of the axial direction. The elastic reset element (12) is one of a disc spring, a wave spring or a rubber elastic pad (12a) and is used to provide a center positioning force.

4. The new energy planetary gear reducer according to claim 3, characterized in that: The elastic reset element (12) is a rubber elastic pad (12a), and an oil storage sponge (13) is fitted on the side facing the common tooth ring (20). An oil storage groove for accommodating the oil storage sponge (13) is provided on the end face of the common tooth ring (20). A through groove is provided on the side of the oil storage groove near the center of the common tooth ring (20) that radially penetrates to the first oblique tooth area (22) or the second oblique tooth area (23). When the common gear ring (20) moves axially, the oil storage sponge (13) at one end is squeezed by the corresponding rubber elastic pad (12a), and the squeezed-out lubricating oil flows into the meshing gap of the corresponding planetary gear and helical gear area through the through groove; the oil storage sponge (13) at the other end absorbs lubricating oil due to the reduced pressure.

5. The new energy planetary gear reducer according to claim 1, characterized in that: The annular sealing cavity (21) is formed by the outer circle of the common toothed ring (20), the inner wall of the shell (10) and the sealing rings (24) on both sides, and the sealing rings (24) are made of fluororubber.

6. The new energy planetary gear reducer according to claim 1, characterized in that: The inner wall of the housing (10) is provided with a limiting pin, and the outer circumferential surface of the common gear ring (20) is provided with an axially extending limiting groove (25). The sliding stroke of the limiting pin in the limiting groove (25) does not exceed 10% of the tooth width of any planetary gear.

7. The new energy planetary gear reducer according to claim 1, characterized in that: The magnetorheological fluid is a silicone oil-based magnetorheological fluid.

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