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EP-4394208-B1 - POWER SHAFT STRUCTURE OF ELECTRIC DRIVE ASSEMBLY

EP4394208B1EP 4394208 B1EP4394208 B1EP 4394208B1EP-4394208-B1

Inventors

  • LI, JIANWEN
  • YU, PING
  • YANG, XUDONG
  • WANG, Ruikun

Dates

Publication Date
20260506
Application Date
20220516

Claims (10)

  1. A power shaft structure of an electric drive assembly, the power shaft structure comprises a main shaft (1), a motor (2) and a reducer (4), wherein a right end of the main shaft (1) is located inside the motor (2) and fixedly connected to a rotor (3) of the motor (2), and a left end of the main shaft (1) is located inside the reducer (4) and fixedly connected to a driving gear (5) and a parking gear (6) of the reducer (4); wherein at least one side of the driving gear (5) is provided with an axially extending first flange (7), and at least one side of the parking gear (6) is provided with an axially extending third flange (22); and a bushing (8) is provided between an inner hole of the first flange (7) at one side of the driving gear (5) and the main shaft (1) characterized in that , the bushing (8) is provided in addition between an inner hole of the third flange (22) at one side of the parking gear (6) and the main shaft (1) for radial positioning of the driving gear (5) and the parking gear (6).
  2. The power shaft structure according to claim 1, characterized in that : the driving gear (5) is provided between the parking gear (6) and the motor (2), the left side of the driving gear (5) is provided with the first flange (7) that extends axially, the right side of the driving gear (5) is provided with a second flange (21) that extends axially, and the right side of the parking gear (6) is provided with the third flange (22) that extends axially; and an inner hole of the second flange (21) matches up with a diameter of the main shaft (1) for radially positioning, and the bushing (8) is provided between an inner hole of the first flange (7) and the main shaft (1) and extends into an inner hole of the third flange (22).
  3. The power shaft structure according to claim 2, characterized in that : a transition fit or an interference fit is formed between the inner hole of the second flange (21) and the main shaft (1); and a transition fit or an interference fit is formed between the inner hole of the first flange (7), the bushing (8) and the main shaft (1), as well as between the inner hole of the third flange (22) and the bushing (8).
  4. The power shaft structure according to claim 2, characterized in that : a left end bearing (9) is provided between a housing of the reducer (4) and the main shaft (1), a right end bearing (11) is provided between a housing of the motor (2) and the main shaft (1), an intermediate housing (12) is provided between the motor (2) and the reducer (4), and a middle bearing (10) is provided between the intermediate housing (12) and the main shaft (1).
  5. The power shaft structure according to claim 4, characterized in that : the second flange (21) presses tightly and fixes a left end face of an inner ring of a middle bearing (10); or a first shaft sleeve (13) is provided on the main shaft (1) on a left side of the middle bearing (10), and is used to press tightly and fix the left end face of the inner ring of the middle bearing (10).
  6. The power shaft structure according to claim 4, characterized in that : the parking gear (6) presses tightly and fixes a right end face of an inner ring of the left end bearing (9); or a second shaft sleeve (14) is provided on the main shaft (1) on a right side of the left end bearing (9), and is used to press tightly and fix the right end face of the inner ring of the left end bearing (9).
  7. The power shaft structure according to claim 4, characterized in that : a pressing ring (15) is provided on a right end face of an outer ring of the left end bearing (9) on the housing of the reducer (4), and the pressing ring (15) presses tightly and fixes the outer ring of the left end bearing (9).
  8. The power shaft structure according to claim 4, characterized in that : a locking nut (16) is provided on the main shaft (1) at a left side of the left end bearing (9), and is used to press tightly and fix the left end face of the inner ring of the left end bearing (9).
  9. The power shaft structure according to any one of claims 1-8, characterized in that : the main shaft (1) is provided with a first external spline (17) and a second external spline (18), the parking gear (6) is provided with a first internal spline (19) engaging with the first external spline (17), and the driving gear (5) is provided with a second internal spline (20) engaging with the second external spline (18).
  10. The power shaft structure according to any one of claims 1-8, characterized in that : the parking gear (6) is connected to the main shaft (1) using a flat key, and the driving gear (5) is connected to the main shaft (1) using a flat key, respectively; or the inner hole of the parking gear (6) and the inner hole of the driving gear (5) are both smooth holes, and are respectively connected to the main shaft (1) with an interference fit.

Description

TECHNICAL FIELD The present invention belongs to the technical field of motor transmission structure, and particularly relates to a power shaft structure of an electric drive assembly. BACKGROUND At present, in order to facilitate the production of motor and reducer of the electric vehicle, the motor shaft and the input shaft of the reducer are usually independently designed, and then connected together through splines or couplings so as to achieve torque transmission between the motor and the reducer. However, this transmission structure is not only complicated, but also increases the axial size between the reducer and the motor, which is not conducive to the overall layout of the vehicle. In addition, due to the poor precision of machining and manufacturing of the parking gear, when the parking gear and the input shaft of the reducer are assembled with a clearance fit, it is difficult to ensure the concentricity between them, which leads to poor dynamic balance and stability of the input shaft of the reducer during rotation, and results in poor NVH (Noise, Vibration, Harshness) performance of the entire electric drive assembly. If the concentricity when the parking gear and the input shaft of the reducer are assembled is improved by improving the machining precision of the parking gear, the manufacturing cost of the parking gear will be greatly increased. Document CN 108 674 179 A, according to its abstract, discloses an integrated electric driving power assembly. The integrated electric driving power assembly comprises a motor and a gearbox; an output shaft of the motor and an input shaft of the gearbox are integrally made to form a spindle of the power assembly; a parking gear is arranged in the gearbox; and the parking gear is fixedly mounted on the spindle. SUMMARY With respect to the above problems, the present invention discloses a power shaft structure of an electric drive assembly to overcome or at least partially solve the above problems. To achieve the above object, the present invention adopts the following technical solutions. The present invention provides a power shaft structure as defined in the independent claim 1. Preferably, the driving gear is provided between the parking gear and the motor, the left side of the driving gear is provided with the first flange that extends axially, the right side of the driving gear is provided with a second flange that extends axially, and the right side of the parking gear is provided with the third flange that extends axially; an inner hole of the second flange matches up with a diameter of the main shaft for radially positioning, and the bushing is provided between an inner hole of the first flange and the main shaft and extends into an inner hole of the third flange. Preferably, a transition fit or an interference fit is formed between the inner hole of the second flange and the main shaft; a transition fit or an interference fit is formed between the inner hole of the first flange, the bushing and the main shaft, as well as between the inner hole of the third flange and the bushing. Preferably, a left end bearing is provided between the housing of the reducer and the main shaft, a right end bearing is provided between the housing of the motor and the main shaft, a intermediate housing is provided between the motor and the reducer, and a middle bearing is provided between the intermediate housing and the main shaft. Preferably, the second flange presses tightly and fixes a left end face of an inner ring of the middle bearing; or a first shaft sleeve is provided on the main shaft on a left side of the middle bearing, and is used to press tightly and fix the left end face of the inner ring of the middle bearing. Preferably, the parking gear presses tightly and fixes a right end face of an inner ring of the left end bearing; or a second shaft sleeve is provided on the main shaft on a right side of the left end bearing, and is used to press tightly and fix the right end face of the inner ring of the left end bearing. Preferably, a pressing ring is provided on a right end face of an outer ring of the left end bearing on the housing of the reducer, and the pressing ring presses tightly and fixes the outer ring of the left end bearing. Preferably, a locking nut is provided on the main shaft at a left side of the left end bearing, and is used to press tightly and fix the left end face of the inner ring of the left end bearing. Preferably, the main shaft is provided with a first external spline and a second external spline, the parking gear is provided with a first internal spline engaging with the first external spline, and the driving gear is provided with a second internal spline engaging with the second external spline. Preferably, the parking gear is connected to the main shaft using a flat key, and the driving gear is connected to the main shaft using a flat key, respectively; or the inner hole of the parking gear and the inner hole of the driving gear