A decoupling mechanism for a reducer intermediate shaft assembly

Abstract

The utility model discloses a kind of intermediate shaft assembly disengaging mechanisms in reducer, its core is in first driven wheel adopts 7-shaped web design, form built-in cavity integrated one-way clutch assembly.One-way clutch is composed of inner ring, 8-shaped metal wedge, retainer and leaf spring, inner ring is connected with first driven wheel with interference, outer ring is with intermediate shaft spline cooperation.When positive drive, wedge self-locking realizes torque transmission: input shaft→first driven wheel→one-way clutch→intermediate shaft→output shaft;Under sliding condition, wheel end counter drag power makes the rotation speed of outer ring exceed inner ring, wedge removes self-locking, interrupts torque transmission, significantly reduces drag loss.The mechanism realizes the automatic switching of power transmission and disengaging through the directional locking / surpassing function of one-way clutch, combined with impact-resistant structure, directional lubrication and compact layout, solve the problem that traditional reducer counter drag loss is big, wear fast, significantly improve system efficiency and reliability.

Description

Technical Field

[0001] This utility model relates to the field of electric drive reducers for new energy vehicles, and specifically to a mechanism for disengaging the intermediate shaft assembly of a reducer. Background Technology

[0002] As competition intensifies among new energy vehicle manufacturers regarding driving range, optimizing the energy consumption of electric drive systems has become a key industry focus. Currently, for four-wheel drive models, new energy vehicle OEMs primarily implement this by equipping the front and rear axles with two powertrains respectively. The vehicle's VCU (Vehicle Control Unit) manages the distribution and control of these two electric drive systems, enabling switching between two-wheel drive and four-wheel drive modes. In four-wheel drive mode, both the front and rear axles generate power; in two-wheel drive mode, only one powertrain generates power. Therefore, of the two drivetrains, one is always the primary drive and the other is always the secondary drive.

[0003] Throughout the vehicle's lifecycle, two-wheel drive is sufficient for most operating conditions. The main drive unit is a single drive unit, while the auxiliary drive unit remains dormant and does not generate power. However, the auxiliary drive unit rotates along with the main drive unit, resulting in power loss. In particular, the auxiliary drive motor, typically a permanent magnet synchronous motor, generates cogging torque, leading to drag losses due to back electromotive force (approximately 8%–12% of total energy consumption). Therefore, a disengagement mechanism is currently added to the auxiliary drive unit to disconnect the drive motor and reducer within the drive unit, preventing back electromotive force generation and reducing energy consumption.

[0004] Currently, the mainstream and mature solutions mainly involve integrating a disengagement mechanical structure and an electromagnetic coil drive mechanism into the differential, or integrating a half-shaft disengagement mechanism into one side of the half-shaft. These disengagement structures all have a drive motor or electromagnetic coil unit for driving disconnection, as well as engagement components such as a dog-tooth clutch. They all have drawbacks such as large engagement impact, easy gear breakage, and high energy consumption of the electromagnetic actuator. Utility Model Content

[0005] The purpose of this utility model is to provide a disengagement mechanism for the intermediate shaft assembly of a reducer, which aims to overcome the defects of the prior art and solve the problems of large engagement impact, easy gear damage, and high energy consumption of the electromagnetic actuator in the existing disengagement mechanism.

[0006] Therefore, this utility model proposes a disengagement mechanism for the intermediate shaft assembly of a reducer, comprising: a primary driven wheel, an intermediate shaft, a support bearing, a needle roller bearing bushing, a needle roller bearing, a one-way clutch, and a support outer ring.

[0007] The spokes of the first-stage driven wheel have a "7"-shaped structure, forming an annular cavity to accommodate the one-way clutch.

[0008] The primary driven wheel and the intermediate shaft are assembled via a needle roller bearing bushing and a needle roller bearing to achieve relative rotation;

[0009] The one-way clutch includes an inner ring, a cage, several wedges, and several springs. The inner ring is interference-fitted with the first-stage driven wheel and supports the outer ring which is splinedly connected to the intermediate shaft. The cage constrains the wedges through a radial window, and the springs keep the wedges tilted and in contact with the inner and outer rings. This allows the first-stage driven wheel to rotate freely in the forward direction and locks the transmission of torque in the reverse direction.

[0010] As a preferred technical solution of this application, the wedge block adopts an asymmetrical figure-eight structure design, with a thinner end near the inner ring and a thicker end near the supporting outer ring, which respectively contacts the inner ring and the outer ring raceway.

[0011] As a preferred technical solution of this application, the ratio of the vertical height H of the cross section where the wedge block is located to the horizontal projected length W is 1:3.

[0012] As a preferred technical solution of this application, the spring is a leaf spring design, with one end of the spring fixed on the cage and the other end of the spring gently abutting against the wedge, so that the wedge is kept in contact with the inner and outer rings and the initial tilt angle is 7° to 15°.

[0013] As a preferred technical solution of this application, the thickness of the spokes of the first-stage driven wheel is 1 / 4 to 1 / 3 of the gear thickness.

[0014] As a preferred technical solution of this application, the primary driven wheel and the intermediate shaft are axially limited by a bearing bushing.

[0015] As a preferred technical solution of this application, a buffer is provided between the primary driven wheel and the outer ring of the support to buffer the impact force.

[0016] As a preferred technical solution of this application, the surfaces of the bearing bushing, needle roller bearing bushing and buffer are hardened by heat treatment or coating process.

[0017] As a preferred technical solution of this application, the intermediate shaft is provided with an axial oil passage and a radial oil collection groove. The lubrication path includes: one path lubricates the spline joint between the intermediate shaft and the outer ring of the support; the other path lubricates the needle roller bearing through the oil hole of the needle roller bearing bushing, and then splashes to the one-way clutch through the radial oil groove of the buffer.

[0018] As a preferred technical solution of this application, the contact area on the outer ring of the support that mates with the wedge is provided with circumferentially distributed oil collection holes.

[0019] The gearbox intermediate shaft assembly disengagement mechanism provided by this utility model has the following beneficial effects:

[0020] 1) Mounted on the intermediate shaft of the parallel shaft reducer, this is a purely mechanical mechanism that relies on mechanical structures such as wedges to disengage. During coasting, the one-way clutch automatically disengages, interrupting the transmission of reverse torque, reducing motor idling resistance, and improving energy efficiency. It requires no complex control system, has a low failure rate and long service life, and is also relatively inexpensive. Compared to electromagnetic disengagement mechanisms, the disengagement time is also shorter, resulting in no energy loss for the entire vehicle.

[0021] 2) A buffer is used to absorb the impact of disengagement, preventing direct collision between the primary driven wheel and the outer ring of the support; the disengagement and engagement process is smooth and the impact force is small, which greatly reduces noise and cost;

[0022] 3) The directional oil circuit design ensures sufficient lubrication of the spline, needle roller bearing and one-way clutch, avoiding fretting wear and overheating; the evenly distributed oil collection holes on the outer ring improve the lubrication uniformity of the wedge block, extend the clutch operating life and increase reliability.

[0023] 4) The “7” shaped spoke design integrates a one-way clutch within a limited space, avoiding additional axial dimension occupation; the “8” shaped structure of the wedge and the precision cage ensure sensitive and reliable locking / unlocking response.

[0024] In addition to the purposes, features, and advantages described above, this application has other purposes, features, and advantages. A further detailed description of this application will be provided below with reference to the figures. Attached Figure Description

[0025] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0026] Figure 1 This is a schematic diagram of the disengagement mechanism of the intermediate shaft assembly of the reducer according to this utility model;

[0027] Figure 2 This is a schematic diagram of the structure of the intermediate shaft in the disengagement mechanism of the intermediate shaft assembly of the reducer of this utility model;

[0028] Figure 3 This is a schematic diagram of the one-way clutch in the disengagement mechanism of the reducer intermediate shaft assembly of this utility model;

[0029] Figure 4 This is a schematic diagram of the buffer component in the disengagement mechanism of the intermediate shaft assembly of the reducer of this utility model;

[0030] Figure 5 This is a schematic diagram of the supporting outer ring in the disengagement mechanism of the reducer intermediate shaft assembly of this utility model;

[0031] Figure 6This is a schematic diagram of the inner ring and the outer ring of the support in the disengagement mechanism of the intermediate shaft assembly of the reducer of this utility model.

[0032] Figure 7 This is a side view of the wedge block in the disengagement mechanism of the intermediate shaft assembly of the reducer of this utility model;

[0033] Explanation of reference numerals in the attached drawings: 1. Input shaft assembly; 2. Intermediate shaft assembly; 3. Output shaft assembly; 4. Short half-shaft; 5. Long half-shaft; 21. First-stage driven wheel; 22. Intermediate shaft; 23. Right support bearing; 24. Left support bearing; 25. Bearing bushing; 26. Needle roller bearing bushing; 27. Needle roller bearing; 28. Buffer; 29. ​​One-way clutch; 210. Support outer ring; 211. Radial oil groove; 212. Oil collection hole; 213. Axial oil groove; 214. Oil collection groove; 291. Inner ring; 292. Cage; 293. Wedge; 294. Spring. Detailed Implementation

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] according to Figure 1 , Figure 2 As shown, the reducer transmission system of this utility model consists of an input shaft assembly 1, an intermediate shaft assembly 2, an output shaft assembly 3, a short half-shaft 4, and a long half-shaft 5. When the vehicle moves forward and the drive system operates, the power flow transmitted by the motor input torque is as follows: Figure 1 As shown, the input shaft is connected to the motor shaft. The motor torque is transmitted from the input shaft assembly 1 through the first-stage gear pair to the intermediate shaft, then through the second-stage gear to the output shaft, and finally through the differential to the two end half-shafts, which are connected to the wheel ends.

[0036] like Figure 2 As shown, the disengagement mechanism of the intermediate shaft assembly of the reducer of this utility model includes: a primary driven wheel 21, an intermediate shaft 22, a right support bearing 23, a left support bearing 24, a bearing bushing 25, a needle roller bearing bushing 26, a needle roller bearing 27, a buffer 28, a one-way clutch 29, and a support outer ring 210, etc.

[0037] When power flows through the intermediate shaft assembly 2, the power is first transmitted from the first-stage driven wheel 21 to the one-way clutch 29. The inner ring 291 is interference-fitted with the first-stage driven wheel 21. The torque transmitted by the first-stage driven wheel 21 passes through the inner ring 291 and rotates at a certain angle. The wedge block 293 is squeezed and interference-fitted with the inner ring 291 and the supporting outer ring 210, transmitting the torque to the supporting outer ring 210. The supporting outer ring 210 is splined with the intermediate shaft 22, so the torque is then transmitted to the intermediate shaft 22.

[0038] Specifically, the spokes of the first-stage driven wheel 21 differ from those of conventional gears, resembling the shape of a "7". They mate with the inner ring to form an annular cavity for assembling the one-way clutch 29. The thickness of the spokes is typically 1 / 4 to 1 / 3 of the gear thickness. The first-stage driven wheel 21 and the intermediate shaft 22 are supported and assembled via needle roller bearing bushings 26 and needle roller bearings 27, allowing relative rotation between them. The needle roller bearing bushings 26 require heat treatment or coating processes to increase surface hardness, thereby improving wear resistance, extending bearing life, and preventing wear on the intermediate shaft.

[0039] The primary driven wheel 21 and the intermediate shaft 22 are axially limited by the bearing bushing 25 and the left support bearing 24. By controlling the circumferential dimensional tolerance of the intermediate shaft step, the primary driven wheel is made to have a clearance fit in the axial dimension. The bearing bushing 25 and the spokes of the primary driven wheel 21 have relative rotational motion. The bearing bushing 25 also needs to undergo some heat treatment processes to improve the surface hardness of the parts, increase wear resistance, and reduce wear.

[0040] The driven wheel 21 and the supporting outer ring 210 rotate relative to each other, and there is a certain impact force during the disengagement process. Therefore, a ring-shaped buffer 28 is designed between the driven wheel 21 and the supporting outer ring 210 in the axial direction. The buffer 28 is heat treated to improve the surface hardness of the parts and enhance the wear resistance of the surfaces during the mutual operation of the two parts. During the disengagement process, it also prevents the driven wheel 21 from directly impacting the supporting outer ring 210, thus playing a buffering role.

[0041] like Figure 3 As shown, the one-way clutch 29 consists of an inner ring 291, a cage 292, several wedges 293 and several springs 294. The precision requirements of the inner ring 291 are similar to those of the inner ring of a deep groove ball bearing. Its structure is a single inner ring with a retaining ring, which facilitates positioning and assembly.

[0042] The wedge 293 adopts an "8" shaped structural design. The number of wedges 293 is determined by the torque and can be designed as 20 to 40, distributed in a ring array on the cage 292. The wedge has a special shape with an asymmetrical design in the upper and lower parts. It is usually thicker at the end near the outer ring 210 and thinner at the end near the inner ring 291, roughly wedge-shaped in cross-section. The dimensions of the arc surfaces at both ends and the middle support point of the wedge are special. The two arc-shaped end faces contact the inner and outer ring raceways respectively, forming relatively inclined working surfaces. When locking is required in the transmission direction, the thin end of the wedge is squeezed into the narrowing gap between the inner and outer rings, and the self-locking effect of the friction generated by the inclined surface achieves a rigid connection.

[0043] Among them, such as Figure 7As shown, the width ratio of one side of wedge 293 is 1:3, that is, in the trapezoidal cross section of the wedge, the ratio of the vertical height H from the top of the inclined plane to the bottom edge to the horizontal projection length W of the inclined plane on the same side is 1:3.

[0044] The retainer 292 is designed as a ring, and the position of the wedge 293 is constrained by a radial window with a spacing error of ≤0.2mm. The spring 294 is a leaf spring design, with one end of the spring 294 fixed to the retainer 292 and the other end of the spring 294 gently abutting against the wedge 293 to ensure that the wedge is always in contact with the inner and outer rings and remains in the initial position, and keeps the wedge at an inclination angle of 7° to 15° to ensure sensitive and reliable locking / unlocking response.

[0045] When the driven wheel 21 attempts to rotate in the direction permitted by the wedge's tilt (assuming clockwise), friction will push the wedge along the gap between the inner and outer rings in the direction where the gap widens (towards the thicker end of the wedge). The wedge can easily roll or slide in this direction without jamming the inner and outer rings. At this time, the clutch is in an "overrunning" state, and the inner and outer rings can rotate relatively freely (or rotate in the same direction but without rigid connection), without transmitting torque.

[0046] When the first-stage driven wheel 21 attempts to rotate in the opposite direction (assuming counterclockwise), friction pushes the wedge along the gap between the inner and outer rings towards the narrowing direction (the thinner end of the wedge). The wedge is quickly squeezed into the increasingly narrow wedge-shaped space formed between the inner and outer rings, and the two inclined surfaces (or curved surfaces) of the wedge simultaneously generate strong friction with the inner and outer rings and are pressed tightly together. The greater the force of the counter-rotation, the tighter the wedge is squeezed, the greater the friction, and the more secure the lock. At this time, the one-way clutch is in the "locked" state, the inner and outer rings are rigidly locked together, torque is transmitted, and the first-stage driven wheel 21 and the supporting outer ring 210 can drive the intermediate shaft to rotate together.

[0047] like Figure 6 As shown, the eccentric design of the inner ring 291 and the supporting outer ring 210 will cause changes in the gap between the wedge and the inner and outer wheels. Therefore, the inner ring 291 and the supporting outer ring 210 need to have a high degree of concentricity. The concentricity error value needs to be controlled within a certain range, Jmax-Jmin≤0.1mm; to avoid the wedge from getting stuck due to uneven gap.

[0048] When the electric drive is used as an auxiliary drive and the motor is not working, the power flow of its transmission system is as follows: Figure 1 As shown by the dotted line, the auxiliary drive rotates with the entire vehicle, transmitting power from the half-shaft to the output shaft assembly 3 and then to the intermediate shaft 22. Its supporting outer ring 210 rotates at a high speed along with the intermediate shaft 22. Meanwhile, the primary driven wheel 21 and the one-way clutch 29 are connected to the motor and do not rotate, resulting in a certain speed difference between them.

[0049] like Figure 2 , Figure 4 , Figure 5 As shown, the disengagement mechanism of this utility model is designed with a lubrication flow scheme to reduce problems such as temperature rise caused by mutual friction. Specifically, an oil pipe is connected to one end of the inner cavity of the intermediate shaft, and there is a radial oil collection groove 214 in the inner hole of the intermediate shaft. During the operation of the intermediate shaft, one path of oil flows into the spline mating area between the intermediate shaft 22 and the outer ring 210 of the support, preventing spline fretting wear. Another path of oil flows from the oil hole on the intermediate shaft and the oil hole of the needle roller bearing bushing 26 into the needle roller bearing 27. Under the action of centrifugal force, it flows through the radial oil groove 211 on the buffer 28 and into the axial oil groove 213 of the outer ring 210 of the support, and is splashed to lubricate the one-way clutch. In addition, an oil collection hole 212 is designed in the contact area between the outer ring 210 of the support and the wedge block 293. The oil collection holes are evenly distributed in a circle, which helps to improve the service life of the one-way clutch.

[0050] The working principle and process of the disengagement mechanism of the reducer intermediate shaft assembly of this utility model are briefly described below.

[0051] Forward drive mode (lock-up torque transmission):

[0052] The motor torque is transmitted from the input shaft assembly 1 to the first-stage driven wheel 21 and then to the inner ring 291. The wedge block 293 moves towards the thin end under the action of friction and squeezes into the narrowing gap between the inner and outer rings to form a self-locking rigid connection. The torque is transmitted to the wheel end via the supporting outer ring 210, the intermediate shaft 22, the output shaft assembly 3, the long half-shaft 5, and the short half-shaft 4.

[0053] Glide disengagement state (beyond free spin):

[0054] When the auxiliary drive motor stops, the reverse drag force at the wheel end passes through the long half-shaft 5, the short half-shaft 4, the output shaft assembly 3, the intermediate shaft 22, and the support outer ring 210. The speed of the support outer ring 210 is higher than that of the first-stage driven wheel 21, and the wedge block 293 moves towards the thick end, releasing the self-locking. The one-way clutch enters the overrunning state, interrupting the torque transmission between the first-stage driven wheel 21 and the intermediate shaft 22.

[0055] The disengagement function of this invention is mainly assembled between the intermediate shaft and the primary driven gear of a two-stage three-axis parallel reducer. The parallel shaft reducer mainly includes an input shaft assembly, an intermediate shaft assembly, and an output shaft assembly. During vehicle operation, the drive motor transmits torque to the input shaft, which then transmits it to the primary driven gear via a primary gear pair. The primary driven gear then transmits the torque to the intermediate shaft via a one-way clutch. The intermediate shaft and the primary driven gear form the intermediate shaft assembly. The intermediate shaft transmits torque to the output shaft assembly via a secondary gear pair, and then transmits it to the two end half-shafts via the differential in the output shaft assembly, ultimately outputting to the two wheels of the vehicle.

[0056] The disengagement mechanism is mounted on the intermediate shaft assembly. The primary driven wheel, through a “7”-shaped spoke design, has an inner ring-type wedge-shaped one-way clutch inside the gear cavity. By changing the inclination angle of the wedge and the contact area with the outer ring of the support, the intermediate shaft assembly can transmit torque clockwise or counterclockwise, but not in the opposite direction.

[0057] To enhance reliability, a buffer is incorporated to absorb the impact of disengagement, and key moving parts undergo hardening treatment to improve wear resistance. The lubrication system provides two-way lubrication to the splines, needle roller bearings, and one-way clutch via an intermediate shaft oil passage, while evenly distributed oil collection holes on the outer ring optimize wedge lubrication. This mechanism combines the advantages of compact layout, efficient disengagement, and long service life.

[0058] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A disengagement mechanism for a reducer intermediate shaft assembly, applied to the intermediate shaft of a two-stage three-axis parallel reducer, characterized in that, include: The components include a primary driven wheel (21), an intermediate shaft (22), a support bearing, a needle roller bearing bushing (26), a needle roller bearing (27), a one-way clutch (29), and a support outer ring (210). The spokes of the first-stage driven wheel (21) have a “7” shaped structure, forming an annular cavity to accommodate the one-way clutch (29). The primary driven wheel (21) and the intermediate shaft (22) are assembled through a needle roller bearing bushing (26) and a needle roller bearing (27) to achieve relative rotation; The one-way clutch (29) includes an inner ring (291), a cage (292), several wedges (293), and several springs (294). The inner ring (291) is interference-fitted with the first-stage driven wheel (21) and supports the outer ring (210) to be splinedly connected to the intermediate shaft (22). The cage (292) constrains the wedges (293) through a radial window, and the springs (294) keep the wedges (293) tilted and in contact with the inner and outer rings. This allows the first-stage driven wheel (21) to rotate freely in the forward direction and locks the transmission of torque in the reverse direction.

2. The disengagement mechanism for the intermediate shaft assembly of the reducer according to claim 1, characterized in that, The wedge (293) adopts an asymmetrical figure-eight structure design, with the end near the inner ring (291) being thinner and the end near the supporting outer ring (210) being thicker, and it contacts the inner ring and outer ring raceways respectively.

3. The disengagement mechanism for the intermediate shaft assembly of the reducer according to claim 1, characterized in that, The ratio of the vertical height H of the section where the wedge (293) is located to the horizontal projection length W is 1:

3.

4. The disengagement mechanism for the intermediate shaft assembly of the reducer according to claim 1, characterized in that, The spring (294) is a leaf spring design. One end of the spring (294) is fixed on the cage (292), and the other end of the spring (294) gently abuts against the wedge (293) so that the wedge (293) remains in contact with the inner and outer rings and the initial tilt angle is 7° to 15°.

5. The disengagement mechanism for the intermediate shaft assembly of the reducer according to claim 1, characterized in that, The thickness of the spokes of the first-stage driven wheel (21) is 1 / 4 to 1 / 3 of the gear thickness.

6. The disengagement mechanism for the intermediate shaft assembly of the reducer according to claim 1, characterized in that, The primary driven wheel (21) and the intermediate shaft (22) are axially limited by the bearing bushing (25).

7. The disengagement mechanism for the intermediate shaft assembly of the reducer according to claim 1, characterized in that, A buffer (28) is provided between the primary driven wheel (21) and the supporting outer ring (210) to buffer the impact force.

8. The disengagement mechanism for the intermediate shaft assembly of the reducer according to claim 7, characterized in that, The surfaces of the bearing bushing (25), needle roller bearing bushing (26) and buffer (28) are hardened by heat treatment or coating process.

9. The disengagement mechanism for the intermediate shaft assembly of the reducer according to claim 7, characterized in that, The intermediate shaft (22) is provided with an axial oil passage and a radial oil collection groove (214). The lubrication path includes: one path lubricates the spline joint between the intermediate shaft (22) and the outer ring (210) of the support; the other path lubricates the needle roller bearing (27) through the oil hole of the needle roller bearing bushing (26), and then splashes to the one-way clutch (29) through the radial oil groove (211) of the buffer (28).

10. The disengagement mechanism for the intermediate shaft assembly of the reducer according to claim 1, characterized in that, The outer ring (210) of the support has oil collection holes (212) evenly distributed around its circumference in the contact area with the wedge (293).

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