CN115366672A - Bidirectional mechanical overrunning type permanent magnet two-gear transmission and gear shifting method thereof - Google Patents

Abstract

The invention relates to a bidirectional mechanical overrunning type permanent magnet two-gear transmission and a gear shifting method thereof.A clutch comprises a transmission shell, a driving mechanism, a magnetic field modulation gear speed change mechanism, a speed change mechanism connecting piece, a gear shifting synchronizer and a clutch; the single-stage coaxial magnetic field modulation gear is used as a speed change mechanism, so that the friction energy loss of the speed changer is reduced, and the running vibration and noise are reduced; the clutch selectively connects the high-speed shaft of the speed change mechanism with the power output shaft, the shifting synchronizer with the bidirectional mechanical overrunning function is connected with the low-speed shaft of the speed change mechanism and the output shaft, and after the clutch is engaged, the shifting synchronizer automatically overruns, so that unpowered interrupted shifting is realized, and the shifting process is stable and has no impact; by adopting a coaxial arrangement method, the structure compactness is improved, the modularization degree of the gear shifting mechanism is high, and the gear shifting operation is simple and convenient.

Description

Bidirectional mechanical overrunning type permanent magnet two-gear transmission and gear shifting method thereof

Technical Field

The invention relates to the technical field of electric automobile transmissions, in particular to a bidirectional mechanical overrunning type permanent magnet two-gear transmission and a gear shifting method thereof.

Background

With the development of human science and technology and the continuous improvement of industrial level, environmental problems caused by the emission of a large amount of greenhouse gases are increasingly prominent. In order to reduce the carbon emission, achieve the carbon neutralization goal and alleviate the ecological problems caused by the massive use of fossil energy, countries in the world begin to vigorously develop electric vehicles. The electric automobile mainly comprises a power battery system, a driving system and a whole automobile control system. Because the electric automobile motor has larger starting torque and wider speed regulation range, the driving system of the electric automobile at the present stage adopts a structural form that a single-stage speed reducer is matched with a motor. However, in the case of a single-stage reduction gear, in order to achieve a higher vehicle speed, the reduction ratio of the single-stage reduction gear is designed to be smaller, which results in a larger working torque of the motor, a higher output current, less optimal working efficiency and faster power consumption. Therefore, in order to enable the motor to provide high starting, climbing and accelerating torques in a constant torque interval and provide high running speed in a constant power interval, a two-gear transmission which gives consideration to both economy and dynamic performance of the electric vehicle needs to be designed and researched.

With the emergence of more and more pure electric vehicles, the requirements of people on electric vehicles are not only satisfied with driving comfort and economy, but also hope that the electric vehicles have dynamic property comparable to that of the traditional fuel vehicles. This presents challenges to the performance of two speed transmissions for electric vehicles. It is known from a search of the prior art that chinese patent CN209262227 discloses a two-speed transmission shifting system. Comprises a transmission front shell, a transmission rear shell, a shifting fork shaft and a shifting fork. In this scheme, need break off the power supply when adopting the shift fork to shift gears, lead to the driving in-process to produce and shift and pause to hinder, influence the driving and experience. Chinese patent CN112343981 discloses a pure electric vehicle two-gear transmission without power interruption. The driving gear, the second gear driving gear, the auxiliary gear driving gear and the clutch are sequentially arranged on the input shaft, the main reducer driving gear, the first gear driven gear, the synchronizer, the second gear driven gear and the auxiliary gear driven gear are sequentially arranged on the intermediate shaft, and the main reducer driven gear and the differential mechanism are sequentially arranged on the output shaft. In the scheme, the auxiliary gear and the synchronizer are adopted to realize unpowered interrupted gear shifting. However, according to the scheme, the arrangement of the parallel shafts and the arrangement of the auxiliary gears cause the reducer to be overlarge in size and complex in structure, and meanwhile, due to the fact that the synchronizer is adopted for gear shifting, the problem of gear shifting impact is obvious. Chinese patent CN110748615 discloses a two-gear transmission gear shifting device and a gear shifting method thereof. The automatic transmission comprises a gear seat, a high-speed driving gear, a high-speed driven gear, a low-speed driving gear, a low-speed driven gear, an input shaft, an output shaft, a clutch gear-shifting mechanism and a reverse gear mechanism. According to the scheme, the gear shifting without power interruption during advancing is realized, but the reverse gear is realized by adopting the toothed sliding sleeve, the mechanism complexity is increased, and the noise problem of gear reversing and gear beating exists. Chinese patent CN107763153 discloses a planetary gear type two speed transmission for electric vehicles. Comprises a planetary gear train, a first clutch device and a second clutch device. This scheme cooperates planetary gear mechanism through separately arranging two clutch mechanism and carries out the fender position switching, but because planetary gear mechanism structure is complicated, two clutches control degree of difficulty that mutually cooperate is high, and the ride comfort of shifting is poor, influences the driving comfort. Chinese patent CN105526318 discloses an electric drive system based on a two-gear transmission, which comprises a driving mechanism, a planetary gear train, a brake, a clutch, a one-way overrunning clutch, and an output shaft. This scheme adopts the one-way freewheel clutch of clutch cooperation to keep off the position and switches, has realized that power does not have the interrupt and has switched over, and the ride comfort of shifting is good, nevertheless because the operating characteristic of one-way freewheel clutch leads to needing to use the stopper to realize reversing gear, also needs the clutch break-make cooperation to realize braking energy recovery when the low-order fender, and the control degree of difficulty is high, and the clutch is easy wearing and tearing, influences gearbox life. Chinese patent CN106763619 discloses a two-gear transmission for an electric vehicle, which includes an input shaft assembly, a middle shaft assembly, an output shaft assembly and a box assembly. In the scheme, an arrangement scheme that two groups of gears are placed on parallel shafts is adopted, and gear shifting is realized by adopting two clutches, so that the problem of power interruption can be solved, but the mass of the gearbox is large due to more gears. And friction drag exists in the switching of the other two clutches, so that the gear shifting viscous feeling and the energy loss are increased, and the driving comfort of the vehicle is influenced.

In conclusion, the problems of gear shifting power interruption, noise, gear shifting viscosity, impact and complicated braking energy recovery control generally exist in the existing two-gear gearbox. In addition, in order to overcome various problems, the structural complexity is increased, and the economical efficiency and the reliability of the two-gear transmission are reduced. Therefore, the realization of unpowered smooth gear shifting, quick response braking energy recovery and reduction of vehicle noise caused by the transmission by a relatively simple and reliable structure and a control method are the urgent problems to be solved by a high-performance two-gear transmission.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a bidirectional mechanical overrunning permanent magnet two-speed transmission and a gear shifting method thereof, which overcome the problems of power interruption, impact, noise, etc. during gear shifting of the conventional two-speed transmission based on a magnetic field modulation principle, and make the overall structure more compact and the gear shifting control simpler.

The technical scheme adopted by the invention is as follows:

the invention provides a bidirectional mechanical overrunning type permanent magnet two-gear transmission which comprises a transmission shell, a driving mechanism, a magnetic field modulation gear speed change mechanism, a speed change mechanism connecting piece, a gear shifting synchronizer and a clutch, wherein the driving mechanism is arranged on the transmission shell; the driving mechanism, the magnetic field modulation gear speed change mechanism, the speed change mechanism connecting piece, the gear shifting synchronizer and the clutch are all arranged in the transmission shell;

the driving mechanism comprises a driving motor, an input shaft, an intermediate shaft and an output shaft; the input shaft, the intermediate shaft and the output shaft are connected with the transmission shell through bearings in sequence; the output shaft is fixedly connected with a main speed reducer of the electric automobile; the main shaft of the driving motor is fixedly connected with the input shaft; the driving motor is fixedly connected with the transmission shell;

the gear shifting synchronizer comprises a second connecting member, a common spline shaft section, a first end face ratchet plate, a second end face ratchet plate, an inner ratchet wheel, an inner helical gear, a helical spline shaft section, an outer helical gear, a first reset spring, a pawl mounting section, an axial moving member and a second reset spring; the second connecting member is coaxially and fixedly connected with the common spline shaft section; the first end face ratchet disc is in axial sliding connection with the common spline shaft section through an inner straight spline on the ratchet disc; the first end face ratchet disc can slide rightwards along the common spline shaft section to form one-way contact connection with the second end face ratchet disc; the second end face ratchet plate is coaxially and fixedly connected with the inner ratchet; the second end surface ratchet disc is coaxially and fixedly connected with the inner helical gear; the spiral spline shaft section is coaxially and fixedly connected with the common spline shaft section; the spiral spline shaft section is in axial rotation sliding connection with the outer helical gear through a spiral spline; the pawl mounting section is in axial rotary sliding connection with the shaft section of the spiral spline through the spiral spline; the first return spring is coaxially arranged with the helical spline shaft section, the left side of the first return spring is in contact with the right end face of the outer helical gear, and the right side of the first return spring is in contact with the left end face of the right shaft shoulder of the helical spline shaft section; the lower end of the axial moving component is in sliding connection with the first end face ratchet disc, and the upper end of the axial moving component is in sliding connection with the transmission shell; the second return spring is coaxially arranged with the common spline section, the left side of the second return spring is in contact with the right side of the second connecting member, and the right side of the second return spring is in contact with the end face of the left side of the first end face ratchet disc;

the pawl mounting section comprises an annular mounting frame, a pawl, an inertia actuating member and a tension spring; the annular mounting frame and the inner ratchet wheel are coaxially arranged and can rotate relatively; the right side of the annular mounting frame is fixedly connected with the left side of the inner bevel gear; the pawl is hinged with a hinge column arranged on the annular mounting frame through a middle hinge hole, and the rotation range of the pawl is limited through a limiting column arranged on the annular mounting frame; the inertia actuating member is hinged with the other hinge column arranged on the annular mounting frame through a middle hinge hole; a limiting column fixed on the annular mounting frame is also arranged on the right side of the inertia braking component; the front end of the tension spring is fixedly connected to the tail end of the inertia braking component, and the rear end of the tension spring is hinged to a third hinge column arranged on the annular mounting frame; the tail end of the pawl is in contact connection with the head of the inertia actuating member;

the clutch is fixedly connected with the output shaft and selectively and fixedly connected or disconnected with the intermediate shaft; the clutch is fixedly connected with an inner helical gear of the gear shifting synchronizer;

the magnetic field modulation gear speed change mechanism is coaxially arranged between the input shaft and the intermediate shaft;

and the common spline shaft section of the gear shifting synchronizer is connected with the magnetic field modulation gear speed change mechanism through a speed change mechanism connecting piece.

Further, the magnetic field modulation gear speed change mechanism comprises an inner magnetic wheel with M pairs of magnetic poles, an outer magnetic wheel with N pairs of magnetic poles and a magnetic regulation ring; the magnetic adjusting ring is arranged between the inner magnetic wheel and the outer magnetic wheel; the number of the magnetic pole pairs satisfies that M is less than N; the outer magnetic wheel or the inner magnetic wheel is fixedly connected with the transmission shell; the input shaft is coaxially and fixedly connected with the inner magnetic wheel or the outer magnetic wheel; the intermediate shaft is coaxially and fixedly connected with a rotating component which is fixedly connected with the input shaft in the magnetic field modulation gear speed change mechanism; the magnetic adjusting ring is connected with a common spline shaft section of the gear shifting synchronizer.

Further, the magnetic field modulation gear speed change mechanism adopts axial magnetization or radial magnetization.

Further, the magnetic field modulation gear speed change mechanism adopts radial magnetization; the input shaft is fixedly connected with the outer magnetic wheel; the inner magnetic wheel is fixedly connected with the transmission shell.

Further, the magnetic field modulation gear speed change mechanism adopts axial magnetization; the input shaft is fixedly connected with the inner magnetic wheel; the outer magnetic wheel is fixedly connected with the transmission shell.

A gear shifting method of a bidirectional mechanical overrunning type permanent magnet two-gear transmission is used for switching the forward speed and backing a vehicle and realizing the recovery of braking energy in the braking process; the method comprises the following steps:

s1: the clutch is disconnected with the intermediate shaft, the axial moving component moves leftwards to disconnect the first end face ratchet disc from the second end face ratchet disc, the motor rotates forwards, when the speed reaches a certain value, the tail end of the inertia actuating component in the gear shifting synchronizer is thrown out under the action of inertia force to be contacted with the limiting column, so that the pawl is not limited any more, and the pawl is thrown out under the action of inertia force to be contacted with the inner ratchet wheel; at the moment, the outer helical gear is meshed with the inner helical gear under the pushing of the helical spline, the vehicle starts to advance, at the moment, the axial moving component is in an unloading free state, and the first end face ratchet disc is meshed with the second end face ratchet disc under the action of the spring; at the moment, the vehicle is in a forward 1 gear, and the reduction ratio of the transmission is M + N/M or M + N/N; if the vehicle is braked in the state, the motor stops torque output and serves as a generator to receive torque transmitted from the output end through the second end surface ratchet, the first end surface ratchet and the transmission, and braking energy recovery is achieved;

s2: in the 1-gear driving process of the electric automobile, if the speed meets the gear-up requirement, firstly, an axial moving component moves leftwards to disconnect a first end face ratchet disc and a second end face ratchet disc, a clutch starts to be connected with an intermediate shaft, an inner helical gear of a gear-shifting synchronizer pushes an outer helical gear to perform separation motion along a helical spline, finally, the clutch is fixedly connected with the intermediate shaft, the inner helical gear is disconnected with the outer helical gear, the vehicle is in 2-gear-up, and the speed ratio of a transmission is 1; at this time, if the vehicle is braked, the motor stops torque output, and the generator receives torque transmitted from the output end through the clutch, so that braking energy recovery is realized;

s3: in the normal running process of the 2-gear of the electric automobile, when the running speed of the automobile is reduced to the speed threshold of the 1-gear, the clutch is disconnected from the intermediate shaft, the rotating speed of the motor is gradually increased to the state that the speeds of the inner ratchet pawl and the pawl mounting section of the gear shifting synchronizer are equal to the speed of the inner ratchet wheel, so that the outer helical teeth are meshed with the inner helical teeth under the pushing of the helical splines, the axial moving component is in an unloading free state, the first end face ratchet disc is meshed with the second end face ratchet disc under the action of the spring, and the gear position of the automobile is reduced to the 1-gear;

s4: after the parking and stopping of the electric automobile are finished, the axial moving component moves leftwards, the first end face ratchet disc is disconnected with the second end face ratchet disc, the clutch is always disconnected with the intermediate shaft, the inner ratchet pawl of the gear shifting synchronizer is in an unbooked state, at the moment, no matter how the automobile is pushed by the outside, the torque cannot be transferred to the motor, and the electric automobile is in a neutral state;

s5: the clutch is disconnected with the intermediate shaft, the axial moving component is in a free state, and the first end face ratchet disc is meshed with the second end face ratchet disc under the action of the spring; the motor rotates reversely, the vehicle is in a reverse gear state, and the speed ratio of the transmission is M + N/M or M + N/N.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention utilizes the magnetic field modulation gear as the speed change transmission mechanism of the speed changer, reduces the gear shift impact, reduces the noise of the speed changing box and improves the comfort level of drivers by non-contact transmission torque.

2. The automatic gear shifting synchronizer is matched with the clutch to serve as a gear shifting executing mechanism, so that uninterrupted gear shifting of power is realized, and the running stability of the vehicle is improved.

3. The invention can realize braking power recovery when the vehicle runs at a low gear by switching the working modes of the gear shifting synchronizer, has simple control, reduces the dragging torque of the low-speed magnetic wheel when the vehicle runs at a high gear, and has less energy loss.

4. The invention realizes the reverse gear function by adopting the engagement of the end surface ratchets, simplifies the structure of the transmission and improves the compactness of the transmission.

5. The non-contact magnetic field modulation gear is adopted, so that the influence of the vibration of the power output end on a transmission system can be reduced; the running process does not need lubrication, the running stability of the two-gear transmission under severe conditions is improved, and the maintenance expense of the transmission is saved.

Drawings

Fig. 1 is a schematic structural view of a two speed transmission in embodiment 1 of the invention;

FIG. 2 is a schematic construction diagram showing the forward 1 speed operation state of the two speed transmission of the embodiment 1 of the present invention;

FIG. 3 is a schematic construction diagram showing the forward 2 speed operating state of the two speed transmission of the embodiment 1 of the present invention;

FIG. 4 is a structural schematic view of a reverse operating state of the two speed transmission in the embodiment 1 of the invention;

FIG. 5 is a structural schematic diagram of a neutral operating state of the two speed transmission in embodiment 1 of the present invention;

FIG. 6 is a schematic structural view of a two speed transmission in embodiment 2 of the invention;

FIG. 7 is a schematic structural diagram illustrating the forward 1 operating condition of the two speed transmission of the embodiment 2 of the present invention;

FIG. 8 is a schematic structural diagram illustrating the forward 2 operating condition of the two speed transmission of embodiment 2 of the present invention;

FIG. 9 is a structural schematic diagram of a reverse operating state of the two speed transmission of the embodiment 2 of the present invention;

FIG. 10 is a schematic structural view of a neutral operating state of the two speed transmission in embodiment 2 of the present invention;

FIG. 11 is a schematic structural view of a radial magnetic field modulated gear change mechanism according to the present invention;

FIG. 12 is a schematic diagram of the axial magnetic field modulated gear change mechanism of the present invention;

FIG. 13 is an enlarged schematic view of the interior of the shift synchronizer of the present invention;

fig. 14 is a schematic view of the structure of the pawl mounting section of fig. 13.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

It should be noted that in the description of the present invention, the terms "upper", "lower", "top", "bottom", "one side", "the other side", "left", "right", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are merely for convenience of description and simplification of description, and do not mean that a device or an element must have a specific orientation, be configured and operated in a specific orientation.

The invention provides a bidirectional mechanical overrunning type permanent magnet two-gear transmission, which comprises a gear shifting synchronizer 7, a clutch 9, a transmission shell 12, a driving mechanism, a magnetic field modulation gear speed change mechanism and a speed change mechanism connecting piece, wherein the gear shifting synchronizer is connected with the driving mechanism through a transmission shaft; the drive mechanism, the magnetic field modulation gear change mechanism, the change mechanism connection, the shift synchronizer 7 and the clutch 9 are all arranged inside the transmission housing 12.

The driving mechanism comprises a driving motor 1, an input shaft 2, an intermediate shaft 8 and an output shaft 10; the input shaft 2, the intermediate shaft 8 and the output shaft 10 are connected with a transmission shell 12 sequentially through bearings; the output shaft 10 is fixedly connected with a main speed reducer 11 of the electric automobile; the main shaft of the driving motor 1 is fixedly connected with the input shaft 2; the drive motor 1 is fixedly connected to the transmission housing 12.

As shown in fig. 13 and 14, the shifting synchronizer 7 includes a second connecting member 701, a generally splined shaft section 702, a first end-face ratchet plate 703, a second end-face ratchet plate 704, an inner ratchet 705, an inner helical gear 706, a helical splined shaft section 707, an outer helical gear 708, a first return spring 709, a pawl mounting section 710, an axial moving member 711, and a second return spring 712; the second connecting member 701 is coaxially and fixedly connected with the common spline shaft section 702; the first end face ratchet plate 703 is axially connected with the common spline shaft section 702 in a sliding manner through an inner straight spline on the ratchet plate; the first end surface ratchet disc 703 can slide rightwards along the common spline shaft section 702 to form one-way contact connection with the second end surface ratchet disc 704; the second end face ratchet plate 704 is coaxially and fixedly connected with the inner ratchet 705; the second end-face ratchet plate 704 is coaxially and fixedly connected with the inner helical gear 706; the helical spline shaft section 707 is coaxially and fixedly connected with the common spline shaft section 702; the helical spline shaft section 707 is in axial rotation sliding connection with the external helical gear 708 through a helical spline; the pawl mounting section 710 is in axial rotating sliding connection with the helical spline shaft section 707 through a helical spline; the first reset spring 709 is coaxially arranged with the helical spline shaft section 707, the left side of the first reset spring is in contact with the right end face of the external helical gear 708, and the right side of the first reset spring is in contact with the left end face of the right shoulder of the helical spline shaft section 707; the lower end of the axial moving member 711 is in sliding connection with the first end surface ratchet plate 703, and the upper end of the axial moving member 711 is in sliding connection with the transmission housing; the second return spring 712 is coaxially arranged with the ordinary spline section 702, and the left side thereof is in contact with the right side of the second connecting member 701, and the right side thereof is in contact with the left end face of the first end face ratchet plate 703.

Wherein the pawl mounting section 710 includes an annular mounting bracket 7101, a pawl 7102, an inertia actuating member 7103, and a tension spring 7104; the annular mounting rack 7101 and the inner ratchet 705 are coaxially arranged and can rotate relatively; the right side of the annular mounting rack 7101 is fixedly connected with the left side of the inner bevel gear 706; the pawl 7102 is hinged with a hinge column arranged on one side of the annular mounting frame 7101 through a middle hinge hole, and the rotation range of the pawl 7102 is limited through a limit column arranged on the annular mounting frame 7101; the inertial actuating member 7103 is hinged with a hinge post arranged on the other side of the annular mounting frame through a middle hinge hole; a limiting column fixed on the annular mounting frame 7101 is also arranged on the right side of the inertia braking component 7103; the front end of the tension spring 7104 is fixedly connected to the tail end of the inertia brake component 7103, and the rear end of the tension spring 7104 is hinged to a third hinge column on the annular mounting frame 7101; the tail end of the pawl 7102 is in contact connection with the head of the inertia actuating member 7103.

One side of the clutch 9 is fixedly connected with the output shaft and selectively and fixedly connected or disconnected with the intermediate shaft 8, and the other side of the clutch 9 is fixedly connected with the inner helical gear 706 of the gear shifting synchronizer 7; the magnetic field modulation gear change mechanism is coaxially arranged between the input shaft 2 and the intermediate shaft 8.

As shown in fig. 11 and 12, the magnetic field modulation gear speed change mechanism comprises an inner magnetic wheel 3 with M pairs of magnetic poles, an outer magnetic wheel 5 with N pairs of magnetic poles and a magnetic field adjusting ring 4; the magnetic adjusting ring 4 is coaxially arranged between the inner magnetic wheel 3 and the outer magnetic wheel 5; the number of the magnetic pole pairs satisfies that M is less than N; the outer magnetic wheel 5 or the inner magnetic wheel 3 is fixedly connected with the transmission shell 12; the input shaft 2 is coaxially and fixedly connected with the inner magnetic wheel 3 or the outer magnetic wheel 5; the intermediate shaft 8 is coaxially and fixedly connected with a rotating component which is fixedly connected with the input shaft 2 in the magnetic field modulation gear speed change mechanism; the magnetic regulating ring 4 is connected with a common spline shaft section 702 of the gear shifting synchronizer 7.

The magnetic field modulation gear speed change mechanism is an axial magnetizing magnetic field modulation gear or a radial magnetizing magnetic field modulation gear.

When the magnetic field modulation gear speed change mechanism adopts a radial magnetizing magnetic field modulation gear, the input shaft 2 is fixedly connected with the outer magnetic wheel 5, and the inner magnetic wheel 3 is fixedly connected with the transmission shell 12.

When the magnetic field modulation gear speed change mechanism adopts an axial magnetizing magnetic field modulation gear, the input shaft 2 is fixedly connected with the inner magnetic wheel 3; the outer magnetic wheel 5 is fixedly connected with the transmission housing 12.

A gear shifting method of a bidirectional mechanical overrunning type permanent magnet two-gear transmission is used for switching the forward speed and backing a vehicle and realizing the recovery of braking energy in the braking process; the method comprises the following steps:

s1: the clutch 9 is disconnected from the intermediate shaft 8, the axial moving member 711 moves leftwards to disconnect the first end face ratchet disc 703 from the second end face ratchet disc 704, the driving motor 1 rotates forwards, when the speed reaches a certain value, the tail end of the inertia actuating member 7103 in the shifting synchronizer is thrown out under the action of inertia force to be contacted with the limiting column, so that the pawl 7102 is not limited any more, and the pawl 7102 is thrown out under the action of inertia force to be contacted with the inner ratchet 705; at this time, the outer helical gear 708 is meshed with the inner helical gear 706 under the pushing of the helical spline, the vehicle starts to advance, at this time, the axial moving member 711 is in an unloading free state, and the first end-face ratchet plate 703 is meshed with the second end-face ratchet plate 704 under the action of the spring; at the moment, the vehicle is in a forward 1 gear, and the reduction ratio of the transmission is M + N/M or M + N/N; if the vehicle is braked in the state, the driving motor 1 stops torque output and serves as a generator to receive torque transmitted from the output end through the second end surface ratchet plate, the first end surface ratchet plate and the transmission, so that braking energy recovery is realized;

s2: in the process of 1-gear driving of the electric automobile, if the speed reaches the upshift requirement, firstly, the axial moving member 711 moves leftwards to disconnect the first end face ratchet disc from the second end face ratchet disc, the clutch 9 starts to be connected with the intermediate shaft 8, the inner helical gear 706 of the shifting synchronizer pushes the outer helical gear 708 to perform separation motion along the helical spline, and finally, the clutch 9 is fixedly connected with the intermediate shaft 8, the inner helical gear 706 is disconnected with the outer helical gear 708, the vehicle is in 2-gear upshift, and the speed ratio of the transmission is 1; at this time, if the vehicle is braked, the driving motor 1 stops torque output, and the generator receives torque transmitted from the output end through the clutch 9, so that braking energy recovery is realized;

s3: in the normal running process of the 2-gear of the electric automobile, when the running speed of the automobile is reduced to the speed threshold of the 1-gear, the clutch 9 is disconnected from the intermediate shaft 8, the rotating speed of the driving motor 1 is gradually increased to the state that the speed of the inner pawl 7102 of the shifting synchronizer is equal to that of the inner ratchet wheel 705, so that the outer helical gear 708 is meshed with the inner helical gear 706 under the pushing of the helical spline, the axial moving member 711 is in an unloading free state, the first end face ratchet wheel 703 is meshed with the second end face ratchet wheel 704 under the action of the spring, and the gear position of the automobile is reduced to the 1-gear;

s4: after the parking and stopping of the electric automobile are completed, the axial moving member 711 moves leftwards, the first end face ratchet disc 703 and the second end face ratchet disc 704 are disconnected, the clutch 9 and the intermediate shaft 8 are always disconnected, the inner ratchet 7102 of the shifting synchronizer is in an unbooked state, at this time, no matter how the automobile is pushed by the outside, the torque cannot be transferred to the driving motor 1, and the electric automobile is in a neutral state;

s5: the clutch 9 is disconnected from the intermediate shaft 8, the axial moving member 711 is in a free state, and the first end face ratchet disc is engaged with the second end face ratchet disc under the action of the spring; the driving motor 1 rotates reversely, the vehicle is in a reverse gear state, and the speed ratio of the transmission is M + N/M or M + N/N.

The invention is further illustrated by the following specific examples:

example 1:

as shown in the attached figure 1, the bidirectional mechanical overrunning type permanent magnet two-gear transmission comprises a transmission shell 12, a driving mechanism, a magnetic field modulation gear speed change mechanism, a gear shifting synchronizer 7, a speed change mechanism connecting piece 6 and a clutch 9; the drive mechanism, the magnetic field modulation gear change mechanism, the shifting synchronizer 7 and the clutch 9 are all arranged in a transmission shell 12.

The driving mechanism comprises a driving motor 1, an input shaft 2, an intermediate shaft 8 and an output shaft 10; the input shaft 2, the intermediate shaft 8 and the output shaft 10 are sequentially connected with a transmission shell through bearings, the output shaft 10 is fixedly connected with a main reducer 11 of the electric automobile, the driving motor 1 is fixedly connected with the input shaft 2, and the driving motor 1 is fixedly connected with the transmission shell 12.

The magnetic field modulation gear speed change mechanism comprises an inner magnetic wheel 3 with M pairs of magnetic poles, an outer magnetic wheel 5 with N pairs of magnetic poles and a magnetic regulation ring 4; the number of the magnetic pole pairs meets the condition that M is smaller than N, and the outer magnetic wheel 5 is fixedly connected with the transmission shell 12; the input shaft 2 is fixedly connected with the inner magnetic wheel 3, and the intermediate shaft 8 is fixedly connected with the inner magnetic wheel 3; the gear shifting synchronizer 7 is fixedly connected with the magnetic adjusting ring 4 through a second connecting component 701 and a speed change mechanism connecting piece 6; in this embodiment, the magnetic field modulation gear speed change mechanism is an axial magnetizing magnetic field modulation gear.

The shifting synchronizer 7 includes a second connecting member 701, a generally splined shaft section 702, a first end-faced ratchet plate 703, a second end-faced ratchet plate 704, an inner ratchet 705, an inner helical gear 706, a helically splined shaft section 707, an outer helical gear 708, a first return spring 709, a pawl mounting section 710, an axial moving member 711 and a second return spring 712.

The second connecting member 701 is coaxially and fixedly connected with the common spline shaft section 702, the first end face ratchet disc 703 is in axial sliding connection with the common spline shaft section 702 through an inner straight spline on the ratchet disc, the first ratchet disc can slide rightwards along the common spline shaft section 702 to form one-way contact connection with the second end face ratchet disc 704, the second end face ratchet disc 704 is coaxially and fixedly connected with the inner ratchet wheel 705, the second end face ratchet disc 704 is coaxially and fixedly connected with the inner helical gear 706, the helical spline shaft section 707 is coaxially and fixedly connected with the common spline shaft section 702, the helical spline shaft section 707 is in axial rotating sliding connection with the outer helical gear 708 through a helical spline, the pawl mounting section 710 is in axial rotating sliding connection with the helical spline shaft section 707 through a helical spline, the first return spring 709 is coaxially arranged with the helical spline shaft section 707, the left side is in contact with the right end face of the outer helical spline shaft 708, the right side is in contact with the left end face of the right shaft shoulder of the helical spline shaft, the lower end of the axial moving member 711 is in sliding connection with the upper groove of the first end face ratchet disc 703, and the upper end of the horizontal upper hole of the transmission housing are in sliding connection. The second return spring 712 is coaxially arranged with the ordinary spline section, the left side of the second return spring 712 is in contact with the right side of the connecting member, and the right side of the second return spring 712 is in contact with the right end face of the first end face ratchet plate 703.

The pawl mounting section 710 includes an annular mounting bracket 7101, a pawl 7102, an inertia actuating member 7103, and a tension spring 7104; the annular mounting rack 7101 and the inner ratchet 705 are coaxially arranged and can relatively rotate; the right side of the annular mounting rack 7101 is fixedly connected with the left side of the inner bevel gear 706; the pawl 7102 is hinged with a first hinge column arranged on the annular mounting frame 7101 through a middle hinge hole, and the rotation range of the pawl 7102 is limited through a limit column arranged on the annular mounting frame 7101; the inertial actuation member 7103 is hinged to a second hinge post mounted on the annular mounting bracket 7101 through a middle hinge hole; a limiting column fixed on the annular mounting frame 7101 is arranged on the right side of the inertia braking component 7103; the front end of the tension spring 7104 is fixedly connected to the tail end of the inertia brake component 7103, and the rear end of the tension spring 7104 is hinged to a third hinge column arranged on the annular mounting rack 7101; the tail end of the pawl 7102 is in contact with the head of 7103.

The clutch 9 is fixedly connected with the output shaft 10, the clutch 9 can be selectively and fixedly connected or disconnected with the intermediate shaft 8, and the left end face of the clutch 9 is fixedly connected with the right end face of the inner helical gear 706 of the shifting synchronizer 7.

Looking from right to left, the spindle rotates clockwise into the forward direction.

As shown in fig. 2 to 5, the shift operation method and the braking energy recovery strategy of embodiment 1:

s1: the clutch 9 is disconnected from the intermediate shaft 8, the axial moving member 711 moves leftwards to disconnect the first end face ratchet disc 703 from the second end face ratchet disc 704, the motor 1 rotates forwards, when the speed reaches a certain value, the inertia braking member 7103 in the shifting synchronizer 7 contacts with the limiting column at the throwing position under the action of inertia force, so that the pawl 7102 is not limited any more, and the pawl 7102 is thrown out under the action of inertia force and contacts with the inner ratchet 705. At this time, the outer helical gear 708 is engaged with the inner helical gear 706 by being pushed by the helical spline 707, and the vehicle starts to advance, at this time, the axially moving member 711 is in an unloaded free state, and the first end-face ratchet plate 703 is engaged with the second end-face ratchet plate 704 by the second return spring 712. To this end, the vehicle is engaged in forward 1 gear with a transmission reduction ratio of M + N/M.

If the vehicle is braked in this state, the motor 1 stops torque output and receives feedback torque from the output end through the output shaft 10, the clutch 9, the shifting synchronizer 7, the speed change mechanism connecting piece 6, the magnetic adjusting ring 4, the inner magnetic wheel 3 and the input shaft 2 as the generator 1, thereby realizing braking energy recovery.

S2: in the process of 1-gear driving of the electric automobile, if the speed meets the upshift requirement, the axial moving member 711 moves leftward to disconnect the first end-face ratchet plate 703 from the second end-face ratchet plate 704, the clutch 9 starts to be engaged with the intermediate shaft 8, the inner helical teeth 706 in the shifting synchronizer 7 push the outer helical gear 708 to perform separation motion along the helical spline 707, and finally, the clutch 9 is fixedly connected with the intermediate shaft 8, the inner helical teeth 706 are disconnected with the outer helical gear 708, the vehicle is in the upshift position of 2, and the transmission ratio is 1. At this time, when the vehicle is braked, the motor stops torque output, and the generator 1 receives the feedback torque from the output terminal via the output shaft 10, the clutch 9, the intermediate shaft 8, the inner magnetic wheel 3, and the input shaft 2, thereby recovering braking energy.

S3: in the normal running process of the 2-gear of the electric automobile, when the running speed of the automobile is reduced to the speed threshold of the 1-gear, the clutch 9 is disconnected from the intermediate shaft 8, the rotating speed of the motor 1 is gradually increased to the state that the speed of the pawl installation section of the inner pawl overrunning clutch of the gear shifting synchronizer 7 is equal to that of the inner ratchet wheel, so that the outer helical gear 708 is meshed with the inner helical gear 706 under the pushing of the helical spline shaft section 707, the axial moving member 711 is in the unloading free state, and the first end face ratchet disc 703 is meshed with the second end face ratchet disc 704 under the action of the second return spring 712. The vehicle gear is reduced to 1 gear.

S4: after the parking and stopping of the electric automobile are completed, the axial moving member 711 moves leftwards, the first end face ratchet disc 703 is disconnected from the second end face ratchet disc 704, the clutch 9 is always disconnected from the intermediate shaft 8, the inner ratchet 705 in the shifting synchronizer 7 and the ratchet on the pawl mounting section 710 are in an unbooked state, at this time, no matter the automobile is pushed forwards or backwards by the outside, the torque cannot be transferred to the motor, and the electric automobile is in a neutral state.

S5: the clutch 9 is disconnected from the intermediate shaft 8, the axial moving member 711 is in a free state, and the first end-face ratchet plate 703 is engaged with the second end-face ratchet plate 704 under the action of the second return spring 712; the motor 1 rotates reversely, the vehicle is in a reverse gear state, and the speed ratio of the transmission is M + N/M.

Example 2:

as shown in fig. 6, the bidirectional mechanical overrunning permanent magnet two-gear transmission comprises a transmission housing 12, a driving mechanism, a magnetic field modulation gear speed change mechanism, a gear shifting synchronizer 7, a connecting piece 6 and a clutch 9. The drive mechanism, the magnetic field modulation gear change mechanism, the shift synchronizer 7 and the clutch 9 are all arranged in a transmission shell 12.

The driving mechanism comprises a driving motor 1, an input shaft 2, an intermediate shaft 8 and an output shaft 10; the input shaft 2, the intermediate shaft 8 and the output shaft 10 are connected with a transmission shell through bearings, the output shaft 10 is fixedly connected with a main reducer 11 of the electric automobile, the driving motor 1 is fixedly connected with the input shaft 2, and the driving motor 1 is fixedly connected with a transmission shell 12.

The magnetic field modulation gear speed change mechanism comprises an inner magnetic wheel 3 with M pairs of magnetic poles, an outer magnetic wheel 5 with N pairs of magnetic poles and a magnetic regulation ring 4; the number of magnetic pole pairs meets the condition that M is smaller than N, and the inner magnetic wheel 3 is fixedly connected with the transmission shell 12; the input shaft 2 is fixedly connected with the outer magnetic wheel 5, and the intermediate shaft 8 is fixedly connected with the outer magnetic wheel 5; the shifting synchronizer 7 is fixedly connected with the magnetic adjusting ring 4 through a second connecting component 701 and a speed change mechanism connecting piece 6. In this embodiment, the magnetic field modulation gear speed change mechanism is a radial magnetizing magnetic field modulation gear.

The shifting synchronizer 7 includes a second connecting member 701, a generally splined shaft section 702, a first end-face ratchet plate 703, a second end-face ratchet plate 704, an internal ratchet 705, an internal helical gear 706, a helically splined shaft section 707, an external helical gear 708, a first return spring 709, a pawl mounting section 710, an axial moving member 711, and a second return spring 712.

The second connecting member 701 is coaxially and fixedly connected with the common spline shaft section 702. The first end surface ratchet plate 703 is axially connected with the ordinary spline shaft section 702 in a sliding manner through an inner straight spline on the ratchet plate, and the first ratchet plate can slide rightwards along the ordinary spline shaft section 702 to form a one-way contact connection with the second end surface ratchet plate 704. The second end face ratchet disc 704 is coaxially and fixedly connected with the inner ratchet 705, the second end face ratchet disc 704 is coaxially and fixedly connected with the inner helical gear 706, the helical spline shaft section 707 is coaxially and fixedly connected with the ordinary spline shaft section 702, the helical spline shaft section 707 forms axial rotation sliding connection with the outer helical gear 708 through a helical spline, the pawl mounting section 710 forms axial rotation sliding connection with the helical spline shaft section 707 through a helical spline, the first return spring 709 is coaxially arranged with the helical spline shaft section 707, the left side is in contact with the right end face of the outer helical gear 708, the right side is in contact with the left end face of the right shaft shoulder of the helical spline shaft end, the lower end of the axial moving member 711 forms sliding connection with the groove on the first end face ratchet disc 703, and the upper end of the axial moving member 711 forms sliding connection with the horizontal upper hole on the transmission housing. The second return spring 712 is coaxially arranged with the ordinary spline section, the left side of the second return spring 712 is in contact with the right side of the connecting member, and the right side of the second return spring 712 is in contact with the right end face of the first end face ratchet plate 703.

The pawl mounting section 710 includes an annular mounting bracket 7101, a pawl 7102, an inertia actuating member 7103, and a tension spring 7104; the annular mounting 7101 is coaxially arranged with the inner ratchet 705 and can rotate relatively. The right side of the annular mounting bracket 7101 is fixedly connected with the left side of the inner helical gear 706. The pawl 7102 is hinged with a first hinge column on the annular mounting frame 7101 through a middle hinge hole, and the rotation range of the pawl 7102 is limited through a limiting column on the annular mounting frame 7101. 7103 is hinged to a second hinge post on the annular mounting bracket 7101 through a central hinge hole. And a limiting column fixed on the annular mounting frame 7101 is arranged on the right side of the inertia braking component. The front end of the tension spring 7104 is fixedly connected to the tail end of the inertia braking component, and the rear end of the tension spring 7104 is hinged to the third hinge column of the annular mounting frame 7101. The tail end of the pawl 7102 is in contact with the head of 7103.

The clutch 9 is fixedly connected with the output shaft 10, and the clutch 9 can be selectively and fixedly connected or disconnected with the intermediate shaft 8; the clutch 9 is connected to the outer ring of the shifting synchronizer 7.

As shown in fig. 7 to 10, the shift operation method and the braking energy recovery strategy of embodiment 2:

s1: the clutch 9 is disconnected from the intermediate shaft 8, the axial moving member 711 moves leftwards to disconnect the first end face ratchet disc 703 from the second end face ratchet disc 704, the driving motor 1 rotates forwards, when the speed reaches a certain value, the inertia braking member 7103 in the shifting synchronizer 7 contacts with the limiting column at the thrown position under the action of inertia force, so that the pawl 7102 is not limited any more, and the pawl 7102 is thrown out under the action of inertia force and contacts with the inner ratchet 705. At this time, the outer helical gear 708 is engaged with the inner helical gear 706 under the pushing of the helical spline 707, and the vehicle starts to advance, at this time, the axial moving member 711 is in an unloaded free state, and the first end-face ratchet plate 703 is engaged with the second end-face ratchet plate 704 under the action of the second return spring 712; to this end, the vehicle is engaged in forward 1 gear with a transmission reduction ratio of M + N/N. If the vehicle is braked in this state, the driving motor 1 stops torque output, and receives feedback torque from the output end through the output shaft 10, the clutch 9, the shifting synchronizer 7, the speed change mechanism connecting piece 6, the magnetic adjusting ring 4, the inner magnetic wheel 3 and the input shaft 2 as the generator 1, thereby realizing braking energy recovery.

S2: in the process of 1-gear driving of the electric automobile, if the speed meets the upshift requirement, the axial moving member 711 moves leftward to disconnect the first end-face ratchet plate 703 from the second end-face ratchet plate 704, the clutch 9 starts to be engaged with the intermediate shaft 8, the inner helical teeth 706 in the shifting synchronizer 7 push the outer helical gear 708 to perform separation motion along the helical spline 707, and finally, the clutch 9 is fixedly connected with the intermediate shaft 8, the inner helical teeth 706 are disconnected with the outer helical gear 708, the vehicle is in the upshift position of 2, and the transmission ratio is 1. At this time, when the vehicle is braked, the motor stops torque output, and the drive motor 1 receives the feedback torque from the output end to the output shaft 10, the clutch 9, the intermediate shaft 8, the inner magnetic wheel 3, and the input shaft 2, thereby recovering the braking energy.

S3: in the normal running process of the 2-gear of the electric automobile, when the running speed of the automobile is reduced to the speed threshold of the 1-gear, the clutch 9 is disconnected from the intermediate shaft 8, the rotating speed of the driving motor 1 is gradually increased to the state that the speed of the pawl mounting section of the inner pawl overrunning clutch of the gear shifting synchronizer 7 is equal to that of the inner ratchet wheel, so that the outer helical gear 708 is meshed with the inner helical gear 706 under the pushing of the helical spline 707, the axial moving member 711 is in an unloading free state, and the first end face ratchet disc 703 is meshed with the second end face ratchet disc 704 under the action of the second return spring 712. The vehicle gear is reduced to 1 gear.

S4: after the parking and stopping of the electric automobile are completed, the axial moving member 711 moves leftwards to disconnect the first end face ratchet disc 703 from the second end face ratchet disc 704, the clutch 9 is always disconnected from the intermediate shaft 8, the inner ratchet 705 in the shifting synchronizer 7 and the ratchet on the pawl mounting section 710 are in an unbuckled state, and at this time, no matter the vehicle is pushed forwards or backwards by the outside, torque cannot be transferred to the motor, and the electric automobile is in a neutral gear state.

S5: the clutch 9 is disconnected from the intermediate shaft 8, the axial moving member 711 is in a free state, and the first end-face ratchet plate 703 is engaged with the second end-face ratchet plate 704 under the action of the second return spring 712; the driving motor 1 rotates reversely, the vehicle is in a reverse gear state, and the speed ratio of the transmission is M + N/N.

The invention is not well known in the art.

The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solution of the present invention by those skilled in the art should fall within the protection scope defined by the claims of the present invention without departing from the spirit of the present invention.

Claims (6)

1. A two-way mechanical overrunning type permanent magnet two-gear transmission is characterized in that: the transmission comprises a transmission shell, a driving mechanism, a magnetic field modulation gear speed change mechanism, a speed change mechanism connecting piece, a gear shifting synchronizer and a clutch; the driving mechanism, the magnetic field modulation gear speed change mechanism, the speed change mechanism connecting piece, the gear shifting synchronizer and the clutch are all arranged in the transmission shell;

the driving mechanism comprises a driving motor, an input shaft, an intermediate shaft and an output shaft; the input shaft, the intermediate shaft and the output shaft are connected with the transmission shell through bearings in sequence; the output shaft is fixedly connected with a main speed reducer of the electric automobile; the main shaft of the driving motor is fixedly connected with the input shaft; the driving motor is fixedly connected with the transmission shell;

the gear shifting synchronizer comprises a second connecting member, a common spline shaft section, a first end face ratchet plate, a second end face ratchet plate, an inner ratchet wheel, an inner helical gear, a helical spline shaft section, an outer helical gear, a first reset spring, a pawl mounting section, an axial moving member and a second reset spring; the second connecting member is coaxially and fixedly connected with the common spline shaft section; the first end face ratchet disc is in axial sliding connection with the common spline shaft section through an inner straight spline on the ratchet disc; the first end face ratchet disc can slide rightwards along the common spline shaft section to form one-way contact connection with the second end face ratchet disc; the second end surface ratchet disc is coaxially and fixedly connected with the inner ratchet; the second end surface ratchet disc is coaxially and fixedly connected with the inner helical gear; the spiral spline shaft section is coaxially and fixedly connected with the common spline shaft section; the helical spline shaft section is in axial rotation sliding connection with the outer helical gear through a helical spline; the pawl mounting section is in axial rotary sliding connection with the shaft section of the spiral spline through the spiral spline; the first reset spring is coaxially arranged with the helical spline shaft section, the left side of the first reset spring is in contact with the right end face of the outer helical gear, and the right side of the first reset spring is in contact with the left end face of the right shaft shoulder of the helical spline shaft section; the lower end of the axial moving component is in sliding connection with the first end face ratchet disc, and the upper end of the axial moving component is in sliding connection with the transmission shell; the second return spring is coaxially arranged with the common spline section, the left side of the second return spring is in contact with the right side of the second connecting member, and the right side of the second return spring is in contact with the end face of the left side of the first end face ratchet disc;

the pawl mounting section comprises an annular mounting frame, a pawl, an inertia actuating member and a tension spring; the annular mounting frame and the inner ratchet wheel are coaxially arranged and can rotate relatively; the right side of the annular mounting frame is fixedly connected with the left side of the inner helical gear; the pawl is hinged with a hinge column arranged on the annular mounting frame through a middle hinge hole, and the rotation range of the pawl is limited through a limiting column arranged on the annular mounting frame; the inertia actuating member is hinged with another hinge column arranged on the annular mounting frame through a middle hinge hole; a limiting column fixed on the annular mounting rack is also arranged on the right side of the inertia braking component; the front end of the tension spring is fixedly connected to the tail end of the inertia braking member, and the rear end of the tension spring is hinged to a third hinge column arranged on the annular mounting frame; the tail end of the pawl is in contact connection with the head of the inertia actuating member;

the clutch is fixedly connected with the output shaft and selectively and fixedly connected or disconnected with the intermediate shaft; the clutch is fixedly connected with an inner helical gear of the gear shifting synchronizer;

the magnetic field modulation gear speed change mechanism is coaxially arranged between the input shaft and the intermediate shaft;

and the common spline shaft section of the gear shifting synchronizer is connected with the magnetic field modulation gear speed change mechanism through a speed change mechanism connecting piece.

2. The bidirectional mechanical overrunning type permanent magnet two-speed transmission according to claim 1, wherein: the magnetic field modulation gear speed change mechanism comprises an inner magnetic wheel with M pairs of magnetic poles, an outer magnetic wheel with N pairs of magnetic poles and a magnetic regulation ring; the magnetic adjusting ring is arranged between the inner magnetic wheel and the outer magnetic wheel; the number of the magnetic pole pairs satisfies that M is smaller than N; the outer magnetic wheel or the inner magnetic wheel is fixedly connected with the transmission shell; the input shaft is coaxially and fixedly connected with the inner magnetic wheel or the outer magnetic wheel; the intermediate shaft is coaxially and fixedly connected with a rotating component which is fixedly connected with the input shaft in the magnetic field modulation gear speed change mechanism; the magnetic adjusting ring is connected with a common spline shaft section of the gear shifting synchronizer.

3. The bidirectional mechanical overrunning type permanent magnet two-speed transmission according to claim 2, wherein: the magnetic field modulation gear speed change mechanism adopts axial magnetization or radial magnetization.

4. A bi-directional mechanical overrunning permanent magnet two speed transmission of claim 3, wherein: the magnetic field modulation gear speed change mechanism adopts radial magnetization; the input shaft is fixedly connected with the outer magnetic wheel; the inner magnetic wheel is fixedly connected with the transmission shell.

5. A bi-directional mechanical overrunning permanent magnet two speed transmission as claimed in claim 3 wherein: the magnetic field modulation gear speed change mechanism adopts axial magnetization; the input shaft is fixedly connected with the inner magnetic wheel; the outer magnetic wheel is fixedly connected with the transmission shell.

6. A gear shifting method of the bidirectional mechanical overrunning type permanent magnet two-gear transmission according to claim 1 is used for switching the forward speed and backing a vehicle and realizing the recovery of braking energy in the braking process; the method is characterized by comprising the following steps:

s1: the clutch is disconnected with the intermediate shaft, the axial moving component moves leftwards to disconnect the first end face ratchet disc from the second end face ratchet disc, the motor rotates forwards, when the speed reaches a certain value, the tail end of the inertia actuating component in the gear shifting synchronizer is thrown out under the action of inertia force to be contacted with the limiting column, so that the pawl is not limited any more, and the pawl is thrown out under the action of inertia force to be contacted with the inner ratchet wheel; at the moment, the outer helical gear is meshed with the inner helical gear under the pushing of the helical spline, the vehicle starts to advance, at the moment, the axial moving component is in an unloading free state, and the first end face ratchet disc is meshed with the second end face ratchet disc under the action of the spring; at the moment, the vehicle is in a forward 1 gear, and the reduction ratio of the transmission is M + N/M or M + N/N; if the vehicle is braked in the state, the motor stops torque output and serves as a generator to receive torque transmitted from the output end through the second end surface ratchet, the first end surface ratchet and the transmission, and braking energy recovery is achieved;

s2: in the 1-gear driving process of the electric automobile, if the speed meets the gear-up requirement, firstly, an axial moving component moves leftwards to disconnect a first end face ratchet disc and a second end face ratchet disc, a clutch starts to be connected with an intermediate shaft, an inner helical gear of a gear-shifting synchronizer pushes an outer helical gear to perform separation motion along a helical spline, finally, the clutch is fixedly connected with the intermediate shaft, the inner helical gear is disconnected with the outer helical gear, the vehicle is in 2-gear-up, and the speed ratio of a transmission is 1; at this time, if the vehicle is braked, the motor stops torque output, and the generator receives torque transmitted from the output end through the clutch, so that braking energy recovery is realized;

s3: in the normal running process of the 2-gear of the electric automobile, when the running speed of the automobile is reduced to the speed threshold of the 1-gear, the clutch is disconnected with the intermediate shaft, the rotating speed of the motor is gradually increased to the state that the speeds of the inner pawl and the pawl mounting section of the gear shifting synchronizer are equal to the speed of the inner ratchet wheel, so that the outer helical teeth are meshed with the inner helical teeth under the pushing of the helical splines, the axial moving member is in an unloading free state, the first end face ratchet disc is meshed with the second end face ratchet disc under the action of the spring, and the gear position of the automobile is reduced to the 1-gear;

s4: after the parking and stopping of the electric automobile are finished, the axial moving component moves leftwards, the first end face ratchet disc is disconnected with the second end face ratchet disc, the clutch is always disconnected with the intermediate shaft, the inner ratchet pawl of the gear shifting synchronizer is in an unbooked state, at the moment, no matter how the automobile is pushed by the outside, the torque cannot be transferred to the motor, and the electric automobile is in a neutral state;

s5: the clutch is disconnected with the intermediate shaft, the axial moving component is in a free state, and the first end face ratchet disc is meshed with the second end face ratchet disc under the action of the spring; the motor rotates reversely, the vehicle is in a reverse gear state, and the speed ratio of the transmission is M + N/M or M + N/N.

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