New energy automobile transmission mechanism

Abstract

The invention relates to the field of new energy automobile transmission, in particular to a new energy automobile transmission mechanism. The new energy automobile transmission mechanism comprises a motor and a speed reducer body. The speed reducer body is composed of a shell part and a transmission part, the motor is fixed to the shell part, and the output end of the motor is connected with the transmission part and located in the shell part. According to the new energy automobile transmission mechanism, the input end is connected with the motor rotor shaft through the spline, the two sets of planet gears share the planet carrier, and the large planet gear and the small planet gear are connected together through the spline and the like and are meshed with the output sun gear and the fixed sun gear through the planet carrier. And the output frame is connected with the output sun gear to realize power output. The characteristics of high overlapping coefficient, high transmission efficiency and large transmission torque of the spiral bevel gear are utilized, high efficiency can be achieved in a very small space, large-reduction-ratio speed reduction can be achieved, the sun gear and the planet gear are both provided with outer teeth, no inner gear ring exists, and the manufacturing cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of new energy vehicle transmission, and in particular to a new energy vehicle transmission mechanism. Background Art

[0002] In recent years, with the rapid development of new energy vehicle technology and the increasing maturity of three-electric (Electric, Motor, and Electronics) technologies, higher requirements have been placed on NEV transmissions in terms of NVH performance, lightweighting, and transmission efficiency. In the NEV sector, since the size, weight, and cost of motors are directly proportional to their torque, the current trend is to increase the speed ratio by adding a reducer or transmission, reduce motor torque, and increase motor speed. This approach aims to reduce motor size, weight, and cost while maintaining power by increasing motor speed. NEV motor speeds have generally increased from 12,000 to 16,000 rpm to 20,000 to 30,000 rpm. Planetary reduction gears are increasingly being used in NEV reduction gearing due to their high precision, high rigidity, compactness, and high efficiency. Currently, NEV planetary reduction gears mostly employ single-stage NW or two-stage NWG structures. In both these structures, the precision and cost control of the internal gear ring have always been a major challenge for planetary reduction gearing. The cost of a high-precision internal gear ring often accounts for over 50% of the cost of the modified planetary reduction gear. This essentially requires the development of planetary reduction gears without an internal gear ring for higher transmission efficiency.

[0003] The traditional planetary reduction mechanism has the following problems: 1. The cost of the internal gear ring is high and the accuracy is difficult to guarantee. Due to the structural characteristics of the internal gear ring, its gear manufacturing process cannot adopt the more efficient hobbing and worm grinding processes commonly used for external cylindrical gears. The production cycle is long and its cost is much higher than that of ordinary external gears. 2. The meshing gears have a large tooth ratio, a large tooth surface slip coefficient, and low transmission efficiency. At the same time, there is relative motion between the planetary gears and the planetary carrier in both the axial and radial directions, which further reduces the transmission efficiency due to friction.

[0004] 3. High heat dissipation requirements. When the planetary carrier or the internal gear rotates, the gear oil tends to form an oil ring in the circumferential direction due to the centrifugal force, which reduces the lubricating oil of the central sun gear and affects the lubrication of the sun gear.

[0005] Therefore, it is necessary to provide a new new energy vehicle transmission mechanism to solve the above technical problems. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a new energy vehicle transmission mechanism.

[0007] Includes: motor, input shaft, bearing, input stage sun gear, small planet gear, large planet gear, planet carrier, housing fixed sun gear, output end sun gear, output carrier; The input shaft and the motor shaft are integrated and supported and positioned by a pair of bearings. The input shaft is connected to the input stage sun gear via a spline. The input stage sun gear is meshed with the asteroid gear for transmission. The asteroid gear is mounted on the planet carrier through a bearing and meshes with the fixed sun gear fixed to the housing to drive the planet carrier to rotate. The planet carrier is supported and positioned on the input shaft through bearings to drive the large planet gears to rotate around the fixed sun gear; The large planetary gear is connected to the small planetary gear via a spline and meshes with the output end sun gear for transmission; The output end sun gear is supported and positioned on the housing through bearings, and is connected to the output frame through bolts to achieve power output.

[0008] Preferably, the input shaft and the input stage sun gear are connected by a key connection, an interference fit connection, or are combined into one gear shaft part.

[0009] Preferably, the connection method between the fixed sun gear and the housing includes a key connection and an interference connection.

[0010] Preferably, the planet carrier is supported and positioned on the input shaft via bearings.

[0011] Preferably, the large planetary gear is connected to the small planetary gear via a spline by a key connection, an interference connection, a bolt connection, or a welding connection.

[0012] Preferably, the output end sun gear is supported and positioned on the housing through a bearing, and is connected to the output frame in a manner including key connection, interference connection, bolt connection, and welding connection.

[0013] Compared with the prior art, the new energy vehicle transmission mechanism provided by the present invention has the following beneficial effects: The present invention adopts spiral bevel gears for transmission, the gears are all external teeth, the processing technology is mature, the precision is easy to ensure, and the processing difficulty is small.

[0014] The present invention utilizes the characteristic of the spiral bevel gear in changing the power direction to make the planetary gear rotate in two perpendicular directions to the planetary carrier, thereby reducing the rotation diameter of the planetary carrier and saving space.

[0015] The present invention uses gears with similar numbers of teeth to reduce the tooth surface slip coefficient. In addition, the planetary gears rotate in two perpendicular directions to the planetary carrier, and the planetary gear end faces and the planetary carrier do not move relative to each other, thereby improving transmission efficiency.

[0016] The sun gear of the present invention is located at the bottom of the reduction box and can be fully lubricated, and the rotation of the planetary gear is perpendicular to the planetary carrier, so that the oil splashes evenly, thereby fully dissipating the heat of the modified reduction mechanism.

[0017] Compared with the current planetary reduction gears of new energy vehicles, the space is reduced by 20% to 30%, the weight is reduced by 30%-40%, the transmission efficiency is increased by 1%-2%, and the manufacturing cost is reduced by 30-50%. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic structural diagram of a preferred embodiment of the new energy vehicle transmission mechanism provided by the present invention; Figure 2 This is a structural diagram of the transmission principle of the reducer shown in the present invention.

[0019] 1. Motor; 2. Input shaft; 3. Bearing; 4. Input stage sun gear; 5. Small planet gear; 6. Large planet gear; 7. Planet carrier; 8. Housing; 9. Fixed sun gear; 10. Output end sun gear; 11. Output carrier. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0021] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0022] The input shaft 2 and the output shaft of the motor 2 are integrally connected and supported and positioned by a pair of bearings 3. The input shaft 2 is connected to the input stage sun gear 4 via a spline. The input stage sun gear 4 meshes with the asteroid gear 5 for transmission. The asteroid gear 5 is mounted on the planet carrier 7 through a bearing and meshes with the fixed sun gear 9 fixed to the housing 8 to drive the planet carrier 7 to rotate. The planet carrier 7 is supported and positioned on the input shaft 2 through bearings, driving the large planet gears 8 to rotate around the fixed sun gear 9; The large planetary gear 8 is connected to the small planetary gear 5 through a spline and meshes with the output end sun gear 10 for transmission; The output end sun gear 10 is supported and positioned on the housing 8 by bearings and connected to the output frame 11 by bolts to achieve power output; The gear structures used in this planetary reduction mechanism are all spiral bevel gears, which are processed with external teeth and are easy to process. See also Figure 2 According to the design of the traditional structure in this case, we can know that: The input stage sun gear 4 is connected to the rotor shaft of the motor 2 through a spline. The torque and speed are transmitted to the left sun gear through two sets of planetary gears sharing the planetary carrier 7 (where the large planetary gear 6 and the small planetary gear 5 are connected by splines). Then, the output carrier is connected to the output end sun gear 10 to realize power transmission. Since gear 3 is fixed, the small planetary gear 5 and the large planetary gear 6 have the same speed, so: ω2 / ω3=Z2 / Z1 (1) ω1=ω2+ω3*Z2 / Z1 (2) Substitute (1) into (2) ω1=2ω3*Z2 / Z1 (3) Substitute (1) into (3) ω1=2ω2 (4) For the large planet deceleration, the planet carrier 7 and the large planet gear 6 are inputs, then: ω4=ω2-ω3*Z4 / Z3 (5) Substitute (3) and (4) into (5): ω4=1 / 2*ω1 (1-Z1*Z4 / Z2 / Z3) If Z1=28, Z2=27, Z3=28, and Z4=25, a reduction ratio of 27 is achieved.

[0023] The above are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A new energy vehicle transmission mechanism, comprising a motor (1), an input shaft (2), a bearing (3), an input stage sun gear (4), a small planetary gear (5), a large planetary gear (6), a planetary carrier (7), a housing (8) fixing the sun gear (9), an output end sun gear (10), and an output carrier (11); The input shaft (2) and the motor shaft are integrally connected and supported and positioned by a pair of bearings (3). The input shaft (2) and the input stage sun gear (4) are connected via a spline. The input stage sun gear (4) is meshed with the asteroid gear (5) for transmission. The asteroid gear (5) is mounted on the planetary carrier (7) via a bearing and meshes with the fixed sun gear (9) fixed to the housing (8) to drive the planetary carrier (7) to rotate. The planet carrier (7) is supported and positioned on the input shaft (2) through bearings to drive the large planet gear (8) to rotate around the fixed sun gear (9); The large planetary gear (8) is connected to the small planetary gear (5) via a spline and meshes with the output end sun gear (10) for transmission; The output end sun gear (10) is supported and positioned on the housing (8) via bearings, and is connected to the output frame (11) via bolts to achieve power output.

2. The new energy vehicle transmission mechanism according to claim 1, characterized in that: The connection between the input shaft (2) and the input stage sun gear (4) includes a key connection, an interference connection, or being combined into a gear shaft part.

3. The new energy vehicle transmission mechanism according to claim 1, characterized in that: The connection method between the fixed sun gear (9) and the housing (8) includes a key connection and an interference connection.

4. The new energy vehicle transmission mechanism according to claim 1, characterized in that: The planet carrier (7) is supported and positioned on the input shaft (2) via bearings.

5. The new energy vehicle transmission mechanism according to claim 1, characterized in that: The large planetary wheel (8) is connected to the small planetary wheel (5) via a spline in a manner including key connection, interference connection, bolt connection, and welding connection.

6. The new energy vehicle transmission mechanism according to claim 1, characterized in that: The output end sun gear (10) is supported and positioned on the housing (8) via a bearing, and is connected to the output frame (11) in a manner including a key connection, an interference connection, a bolt connection, and a welding connection.

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