Electric two-speed transmission

Abstract

The present invention discloses an electric two-speed transmission, including a shaft, an intermediate shaft, a differential assembly, a housing, a main reducer driving gear, a differential assembly, a main reducer driven gear, a first gear gear assembly, a second gear gear assembly, a first gear driving gear, a second gear driving gear, a second gear transmission mechanism, and a reverse gear transmission mechanism. The shaft, the intermediate shaft, and the differential assembly are all parallelly mounted in the housing through bearings at both ends of each shaft. An integrally formed main reducer driving gear is provided in the middle of the intermediate shaft, and the main reducer driving gear is meshed with the main reducer driven gear on the differential assembly. Through the above method, the present invention provides an electric two-speed transmission, which can reduce the motor noise of electric vehicles, can perform torque damping, put the motor in a more efficient area through gear shifting, and make the whole vehicle more powerful, etc., and can effectively reduce motor indicators and battery indicators.

Description

Technical Field

[0001] The invention relates to the field of transmissions, and in particular to an electric two-speed transmission. Background Art

[0002] At present, the two-speed gearboxes used in pure electric vehicles have the following structures.

[0003] like Figure 1 As shown, this two-speed gearbox with synchronizer shifting belongs to a mechanical automatic transmission (AMT). During use, there is a relatively obvious power interruption phenomenon and the shifting time is long, which affects the driving quality.

[0004] For example Figure 1 In the process of shifting from 1st gear to 2nd gear, the torque of motor 1 needs to drop to 0, and then the gear sleeve of synchronizer 3 is disengaged from the left position to the neutral position, and then motor 1 is adjusted, the gear sleeve of synchronizer 3 moves to the right position, motor 1 loads torque, and the shifting process is completed. It can be seen that the shifting time of the whole process is long, the motor control is relatively complicated, the driving quality is poor, and obvious power interruption can be perceived. In particular, the synchronizer will bring the impact of secondary impact and the disadvantage of low service life of the synchronizer.

[0005] like Figure 2 , 3 As shown, these two types of two-speed gearboxes (dual-clutch two-speed, planetary gearbox two-speed) and CVT two-speed gearboxes are more complex to control during the engagement process, and the planetary gearbox and wet clutch have large oil stirring losses, resulting in low gearbox transmission efficiency. There is also the disadvantage of high cost of using electro-hydraulic or liquid-liquid actuators. Figure 2 The clutch has the disadvantages of large impact and heat generation during the clutch engagement process, and low impact fatigue life of the clutch. Summary of the invention

[0006] The main technical problem solved by the present invention is to provide an electric two-speed transmission. Compared with traditional internal combustion engine vehicles, pure electric vehicles may not be equipped with a gearbox. However, pure electric vehicles equipped with a gearbox have the advantages of reducing motor noise, being able to perform torque damping, putting the motor in a more efficient area through gear shifting, and having stronger power for the entire vehicle. In addition, the motor indicators and battery indicators can be effectively reduced.

[0007] This type of electric two-speed transmission can solve the shortcomings of two-speed transmissions using synchronizer shifting, such as long power interruption time, large shifting impact, and short synchronizer life; it can solve the shortcomings of two-speed transmissions using clutch shifting, such as large impact and heat generation during clutch engagement, and short clutch impact fatigue life; it can solve the shortcomings of two-speed transmissions using CVT, planetary gearboxes or dual clutch shifting, such as complex control during engagement, large oil stirring losses in the planetary gearbox and wet clutch, resulting in low transmission efficiency of the transmission, and high cost of using electro-hydraulic or liquid-liquid actuators.

[0008] In order to solve the above technical problems, a technical solution adopted by the present invention is: to provide an electric two-speed transmission, including a shaft 3, an intermediate shaft 6, a differential assembly 13, a housing 25, a main reduction driving tooth 6a, a differential assembly 13, a main reduction driven tooth 13a, a first gear gear assembly 12, a second gear gear assembly 16, a first gear driving gear 3a, a second gear driving gear 3b, a second gear transmission mechanism, and a reverse gear transmission mechanism, wherein the shaft 3, the intermediate shaft 6 and the differential assembly 13 are all parallelly mounted in the housing 25 through bearings at both ends of each shaft, and an integrally formed main reduction driving tooth 6a is provided in the middle of the intermediate shaft 6, and the main reduction driving tooth 6a and the first gear gear assembly 12 are connected to each other. The main reduction driven teeth 13a on the differential assembly 13 are meshed for transmission, and a first-speed gear assembly 12 and a second-speed gear assembly 16 are coaxially movably sleeved on the intermediate shaft 6 located on both sides of the main reduction driving teeth 6a. An integrally formed first-speed driving gear 3a and a second-speed driving gear 3b are provided on the first shaft 3. The first-speed driving gear 3a is meshed for transmission with the first-speed gear assembly 12, and the second-speed driving gear 3b is meshed for transmission with the second-speed gear assembly 16. The intermediate shaft 6 is transmission-connected to the second-speed gear assembly 16 through a second-speed transmission mechanism, and a reverse gear transmission mechanism transmission-connected to the first-speed gear assembly 12 is matched on the first shaft 3 and the intermediate shaft 6.

[0009] In a preferred embodiment of the present invention, the inner ring of the first gear assembly 12 is provided with a first gear buffer tooth 12c, the outer ring of the first gear assembly 12 is provided with a first gear engaging tooth 12a, and a one-way overrunning clutch 11 is coaxially sleeved between the first gear assembly 12 and the intermediate shaft 6.

[0010] In a preferred embodiment of the present invention, the inner ring of the second gear assembly 16 is provided with second gear buffer teeth 16 c , and the outer ring of the second gear assembly 16 is provided with second gear engaging teeth 16 b .

[0011] In a preferred embodiment of the present invention, the second-gear transmission mechanism includes an electromagnetic driver 18, a left retaining ring 19, a left retaining spring 20, a left spring 21, a second-gear sliding engagement sleeve 17 and a push-pull plate 23. The electromagnetic driver 18 is installed on the inner wall of the housing 25 with the intermediate shaft 6 as the axis. The left retaining ring 19 is coaxially sleeved on the intermediate shaft 6 on the left side of the second-gear gear assembly 16. The left side of the left retaining ring 19 is sequentially sleeved with the left retaining ring 20, the left spring 21, the second-gear sliding engagement sleeve 17 and the push-pull plate 23, and the push-pull plate is tightly pressed against the bearing at the left end of the intermediate shaft 6.

[0012] In a preferred embodiment of the present invention, the reverse gear transmission mechanism includes a friction wheel 1, a one-way clutch 2, a right retaining ring 10, a right retaining spring 9, a right spring 8, a first-gear sliding engagement sleeve 5, and a first-gear sliding engagement tooth 5a. The friction wheel 1 is loosely sleeved on a shaft 3 through the one-way clutch 2. The intermediate shaft 6 is coaxially sleeved with a right retaining ring 10 located on the right side of the first-gear gear assembly 12. The right side of the right retaining ring 10 is coaxially sleeved with a right retaining spring 9, a right spring 8 and a first-gear sliding engagement sleeve 5 in sequence. The outer ring of the first-gear sliding engagement sleeve 5 is provided with a first-gear sliding engagement tooth 5a. The friction wheel 1 and the first-gear sliding engagement sleeve 5 are slidingly and frictionally connected to each other along the circumferential surface.

[0013] The beneficial effects of the present invention are:

[0014] 1. Solve the problems of abnormal gear shifting noise and large gear shifting impact: Use the structure described in the patented "gear shifting engagement assembly and device" to solve the problems of abnormal gear shifting noise, large gear shifting impact and long gear shifting power interruption time.

[0015] 2. Solve the problem of difficulty in shifting gears (failure in shifting gears): adopting hook teeth can prevent gear shifting; adopting a one-way clutch structure, it can be disengaged instantly when shifting gears, and can be quickly wedged to transmit torque when shifting gears.

[0016] 3. Adopt single electromagnetic drive structure to solve the shortcomings of low transmission efficiency, complex control system and high cost.

[0017] 4. The one-way clutch and friction wheel combination structure is adopted to realize the self-driven reverse gear mode, eliminating other actuators and using the power of the power drive motor to shift the reverse gear. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0019] Figures 1 to 3It is the background technology of an electric two-speed transmission of the present invention;

[0020] FIG4 is a structural diagram of a preferred embodiment of an electric two-speed transmission of the present invention;

[0021] Figure 5 It is an enlarged structural diagram of a preferred embodiment of an electric two-speed transmission of the present invention, in which a friction wheel and a first-speed sliding engagement sleeve transmit torque through contact with a friction surface;

[0022] Figure 6 It is an enlarged structural diagram of the action of engaging the first gear and the reverse gear of a preferred embodiment of an electric two-speed transmission of the present invention;

[0023] Figure 7 It is an enlarged structural diagram of the action of shifting into the second gear of a preferred embodiment of an electric two-speed transmission of the present invention;

[0024] Figure 8 It is a structural diagram of a preferred embodiment 2 of an electric two-speed transmission of the present invention;

[0025] Fig. 9 It is a structural diagram of a preferred embodiment 3 of an electric two-speed transmission of the present invention;

[0026] Fig.10 A schematic diagram showing a first gear action;

[0027] Figures 11 to 14 A schematic diagram showing the action of shifting from first gear to second gear;

[0028] Figures 15-17 Schematic diagram showing the action of shifting from second gear to first gear;

[0029] Figures 18 to 21 A schematic diagram showing the action of engaging reverse gear;

[0030] Fig. 22 Schematic diagram of the action of exiting reverse gear.

[0031] Among them, the friction wheel 1, the friction surface 1a of the friction wheel, the one-way clutch 2, the first shaft 3, the first gear driving gear 3a, the second gear driving gear 3b, the first shaft right bearing 4, the first gear sliding engagement sleeve 5, the first gear sliding engagement tooth 5a, the first gear sliding engagement tooth friction surface 5b, the intermediate shaft 6, the main reduction driving tooth 6a, the intermediate shaft right bearing 7, the right spring 8, the right retaining spring 9, the right retaining ring 10, the one-way overrunning clutch 11, the first gear gear assembly 12, the first gear engaging tooth 12a, the first gear gear driven tooth 12 b, first gear buffer tooth 12c, differential assembly 13, main reduction driven tooth 13a, differential right bearing 14, differential left bearing 15, second gear gear assembly 16, second gear gear driven tooth 16a, second gear engaging tooth 16b, second gear buffer tooth 16c, second gear sliding engaging sleeve 17, second gear sliding engaging tooth 17a, electromagnetic driver 18, left retaining ring 19, left retaining spring 20, left spring 21, intermediate shaft left bearing 22, push-pull plate 23, first shaft left bearing 24, housing 25;

[0032] Low-speed sliding coupling sleeve 26, low-speed sliding coupling sleeve friction surface 26a, low-speed sliding coupling sleeve spiral internal spline 26b, intermediate shaft 6, intermediate shaft spiral internal spline 6b, tensioner 27, tensioner spring 28, belt 29, belt internal friction surface 29a, driving pulley 30, driving pulley friction surface 30a, one-way clutch 2, and shaft 3.

[0033] Toothed sliding coupling sleeve 34, toothed sliding coupling sleeve teeth 34a, toothed sliding coupling sleeve spiral internal spline 34b, intermediate shaft 6, intermediate shaft spiral internal spline 6b, elastic clamp 33, driving wheel inner ring 32, driving wheel inner ring friction surface 32a, sliding friction body 31, sliding friction body teeth 31a, sliding friction body friction surface 31b, one-way clutch 2, and shaft 3. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The following is an embodiment of an electric two-speed transmission of the present invention:

[0036] The friction wheel 1 is loosely mounted on a shaft 3 via a one-way clutch 2. The friction wheel friction surface 1a of the friction wheel 1 contacts the first gear sliding engagement tooth friction surface 5b of the first gear sliding engagement tooth 5 as a friction pair, and the two can rotate relative to each other.

[0037] The one-way clutch 2 is installed on the inner ring of the friction wheel 1 , the outer ring of the one-way clutch 2 is in contact with the inner ring of the friction wheel 1 , and the inner ring of the one-way clutch 2 is in contact with a shaft 3 .

[0038] A first gear driving gear 3a and a second gear driving gear 3b are provided on the first shaft 3, and the first shaft 3 is supported on the housing 25 by a first shaft right bearing 4 and a first shaft left bearing 24. The first gear driving gear 3a is combined with the first gear driven gear 12b of the first gear gear assembly 12.

[0039] The inner ring of the first shaft right bearing 4 is connected to the installation position of the first shaft right bearing 3 , and the outer ring of the first shaft right bearing 4 is connected to the housing 25 .

[0040] The first-gear sliding engagement teeth 5 are provided with first-gear sliding engagement teeth 5a. The first-gear sliding engagement teeth 5 are sleeved on the intermediate shaft 6 through a spline guide and can slide axially.

[0041] The intermediate shaft 6 is provided with a main reduction driving gear 6 a. The intermediate shaft 6 is supported on the housing 25 by the intermediate shaft right bearing 7 and the intermediate right bearing 22 .

[0042] The right intermediate shaft bearing 7 is installed to the right intermediate shaft bearing installation position, and the outer ring is connected to the housing 25 .

[0043] The right spring 8 is loosely sleeved on the intermediate shaft 6, the right side is engaged with the low-speed sliding engagement tooth 5, and the left side is pressed against the right retaining spring 9 installed on the intermediate shaft 6.

[0044] The right retaining spring 9 is installed on the intermediate shaft 6.

[0045] The right retaining ring 10 is loosely sleeved on the intermediate shaft 6 , with one end contacting the right retaining spring 9 and the other end contacting the first gear gear assembly 12 .

[0046] The one-way overrunning clutch 11 is installed on the inner ring of the first gear assembly 12 , the outer ring of the one-way overrunning clutch 11 contacts the inner ring of the first gear assembly 12 , and the inner ring of the one-way overrunning clutch contacts the intermediate shaft 6 .

[0047] The first gear gear assembly 12 is provided with first gear engaging teeth 12a, first gear driven teeth 12b, and first gear buffer teeth 12c. The first gear gear assembly 12 is loosely sleeved on the intermediate shaft 6 through the one-way overrunning clutch 11, with the left side pressing against the shoulder of the intermediate shaft 6 and the right side contacting the right retaining ring 10.

[0048] The differential assembly 13 is provided with a main reduction gear 13a. The differential assembly 13 is mounted on the housing 25 via an output left bearing 15 and an output right bearing 14. The main reduction gear 13a is combined with the main reduction driving gear 6a of the intermediate shaft.

[0049] The inner ring of the output right bearing 14 is connected to the right bearing installation position of the differential assembly 13 , and the outer ring of the output right bearing 14 is connected to the housing 25 .

[0050] The inner ring of the output left bearing 15 is connected to the left bearing installation position of the differential assembly 13 , and the outer ring of the output left bearing 15 is connected to the housing 25 .

[0051] The second gear gear assembly 16 is provided with second gear driven teeth 16a, second gear engaging teeth 16b, and second gear buffer teeth 16c. The second gear gear assembly 16 is directly sleeved on the intermediate shaft 6, and the right side is limited by the right retaining ring 10 to limit axial movement. The second gear driven gear 16a is meshed with the second gear driving gear 3b of the first shaft.

[0052] The second gear sliding engagement sleeve 17 is provided with second gear sliding engagement teeth 17a. The second gear sliding engagement sleeve 17 is sleeved on the intermediate shaft 6 through a spline guide sleeve and can slide axially.

[0053] The electromagnetic driver 18 is fixed on the housing 25 .

[0054] The left retaining ring 19 is loosely sleeved on the intermediate shaft 6 , with one end contacting the left retaining spring 20 and the other end contacting the second gear assembly 16 .

[0055] The left retaining spring 20 is mounted on the intermediate shaft 6 .

[0056] The left spring 21 is loosely sleeved on the intermediate shaft 6 , with the left side pressed against the second gear sliding engagement sleeve 17 , and the right side pressed against the left retaining spring 20 on the intermediate shaft 6 .

[0057] The middle left bearing 22 is installed to the left bearing installation position of the middle shaft 6 , and the outer ring is connected to the housing 25 .

[0058] The push-pull plate 23 is sleeved on the intermediate shaft 6, with the left side pressed against the left intermediate shaft bearing 22 or the housing 25, and the right side pressed against the second gear sliding engagement sleeve 17, and radially sleeved on the inner hole of the electromagnetic driver 18.

[0059] The inner ring of the left bearing 24 of the first shaft is connected to the installation position of the left bearing of the first shaft 3 , and the outer ring of the left bearing 24 of the first shaft is connected to the housing 25 .

[0060] Based on the above technical solution, its specific implementation method can be divided into five operations according to the mechanical actions performed, including:

[0061] Action 1: Shift to 1st gear (see Fig.10 ):

[0062] When the motor power is transmitted to the first gear assembly 12 , since the speed of the first gear assembly 12 is higher than that of the intermediate shaft 6 , the one-way overrunning clutch 11 between the first gear assembly 12 and the intermediate shaft 6 is in a wedging state. At this time, the second gear assembly 16 idles on the intermediate shaft 6 .

[0063] Action 2: Shift from 1st gear to 2nd gear (see Figures 11 to 14 ):

[0064] The motor unloads torque and adjusts speed (decelerates). At this time, the first gear gear assembly 12 and the intermediate shaft 6 are in an overrunning state due to the one-way overrunning clutch 11, and the first gear is disengaged; when the motor adjusts the speed to the second gear gear assembly 16 and the second gear sliding engagement sleeve 17, the speed difference is not large, the electromagnetic driver 18 is powered on, and under the suction of the electromagnetic driver 18, the push-pull plate 23 pushes the second gear sliding engagement sleeve 17 to slide on the intermediate shaft 6, so that the second gear sliding engagement teeth 17a and the second gear buffer teeth 16c contact first, and then the second gear sliding engagement teeth 17a contact the second gear buffer teeth 16c. The second gear engagement tooth 16b, at this time, the second gear is engaged, the motor adds torque, drives the first shaft 3 to rotate, and drives the second gear assembly 16 to rotate through the meshing of the second gear driving gear 3b and the second gear driven gear 16a, and the second gear assembly 16 drives the second gear sliding engagement sleeve 17 to rotate through the meshing of the second gear engagement tooth 16b and the second gear sliding engagement tooth 17a, and the second gear sliding engagement sleeve 17 drives the intermediate shaft 6 to rotate through the spline, and the main reduction driving tooth 6a of the intermediate shaft 6 is meshed with the main reduction driven tooth 13a, and the torque is output through the differential assembly 13 to achieve the second gear. At this time, the first gear gear assembly 12 is idling on the intermediate shaft 6.

[0065] Action 3, 2nd gear to 1st gear (see Figures 15-17 ):

[0066] After the motor is unloaded, the left spring 21 pops open the second gear sliding coupling sleeve 17, the second gear gear assembly 16 idles, and the motor speed is adjusted (speed increased). When the speed of the first gear gear assembly 12 exceeds the speed of the intermediate shaft 6, the one-way overrunning clutch 11 is wedged, the motor adds torque, and the first gear is achieved.

[0067] Action 4: Shift to reverse gear (see Figures 18 to 21 ):

[0068] The motor rotates in the reverse direction, driving the shaft 3 to rotate. At this time, the one-way clutch 2 is wedged, and the one-way clutch 2 drives the friction wheel 1 to rotate along with the shaft 3. The friction wheel friction surface 1a of the friction wheel 1 contacts the first gear sliding engagement tooth friction surface 5b of the first gear sliding engagement tooth 5 as a friction pair, driving the first gear sliding engagement sleeve 5 to rotate. The first gear sliding engagement sleeve 5 is guided by the helical spline on the intermediate shaft 6, and the first gear sliding engagement sleeve 5 moves axially. The first gear sliding engagement tooth 5a engages with the first gear engaging gear 12a. When the first gear sliding engagement tooth 5a axially resists the first gear engaging gear 12a and cannot move, the friction pair between the friction wheel 1 and the first gear sliding engagement sleeve 5 begins to slip, and the motor adds torque to drive the first gear gear assembly 12 to rotate through the first gear driving gear 3a meshing with the first gear driven tooth 12b. The first gear sliding engagement tooth 5a engages with the first gear engaging gear 12a, driving the first gear sliding engagement sleeve 5 to rotate. The first gear sliding engagement sleeve 5 is connected to the intermediate shaft 6 through the spline, driving the intermediate shaft 6 to rotate, and the main reduction driving tooth 6a of the intermediate shaft 6 meshes with the main reduction driven tooth 13a, and the torque is output through the differential assembly 13 to achieve reverse gear. At this time, the second gear assembly 16 is idling on the intermediate shaft 6 .

[0069] Action 5: Exit reverse gear (see Fig. 22 ):

[0070] The motor stops, and the right spring 8 pops out the first gear sliding coupling sleeve 5, exiting the reverse gear.

[0071] Regarding the action of engaging reverse gear in the fourth gear, the second embodiment of the present invention is specifically described as follows:

[0072] The R gear action is realized by the friction of the pulley: the motor reverses to drive the shaft 3 to rotate, at which time the one-way clutch 2 is wedged, and the one-way clutch 2 drives the driving pulley 30 to rotate with the shaft 3. The driving pulley friction surface 30a of the driving pulley 30 contacts the inner friction surface 29a of the belt 29 as a friction pair, driving the belt 29 to rotate, and the inner friction surface 29a of the belt 29 contacts the low-speed sliding engagement sleeve friction surface 26a of the low-speed sliding engagement sleeve 26 as a friction pair, driving the low-speed sliding engagement sleeve 26 to rotate, and the low-speed sliding engagement sleeve spiral internal spline 26b of the low-speed sliding engagement sleeve 26 cooperates with the intermediate shaft spiral internal spline 6b on the intermediate shaft 6, and the low-speed sliding engagement sleeve 26 moves axially under the action of the spiral spline, and then the reverse gear is engaged.

[0073] Regarding the action of engaging reverse gear in the fourth gear, the embodiment 3 of the present invention is specifically described as follows:

[0074] The R gear action is realized by sliding friction: the motor reverses, driving the shaft 3 to rotate, at which time the one-way clutch 2 is wedged, and the one-way clutch 2 drives the inner ring 32 of the driving wheel to rotate with the shaft 3. The inner ring friction surface 32a of the driving wheel inner ring 32 contacts the sliding friction body friction surface 31b of the sliding friction body 31 as a friction pair, driving the sliding friction body 31 to rotate, and the sliding friction body teeth 31a of the sliding friction body 31 contact the toothed sliding engagement sleeve teeth 34a of the toothed sliding engagement sleeve 34 as a friction pair, driving the toothed sliding engagement sleeve 34 to rotate, and the toothed sliding engagement sleeve spiral internal spline 34b of the toothed sliding engagement sleeve 34 cooperates with the intermediate shaft spiral internal spline 6b on the intermediate shaft 6, and the toothed sliding engagement sleeve 34 moves axially under the action of the spiral spline, and then the reverse gear is engaged.

[0075] In summary, the present invention provides an electric two-speed transmission, which has the following beneficial effects:

[0076] 1. Solve the problems of abnormal gear shifting noise and large gear shifting impact: Use the structure described in the patented "gear shifting engagement assembly and device" to solve the problems of abnormal gear shifting noise, large gear shifting impact and long gear shifting power interruption time.

[0077] 2. Solve the problem of difficulty in shifting gears (failure in shifting gears): adopting hook teeth can prevent gear shifting; adopting a one-way clutch structure, it can be disengaged instantly when shifting gears, and can be quickly wedged to transmit torque when shifting gears.

[0078] 3. Adopt single electromagnetic drive structure to solve the shortcomings of low transmission efficiency, complex control system and high cost.

[0079] 4. The one-way clutch and friction wheel combination structure is adopted to realize the self-driven reverse gear mode, eliminating other actuators and using the power of the power drive motor to shift the reverse gear.

[0080] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An electric two-speed transmission, characterized in that: The invention comprises a first shaft, an intermediate shaft, a differential assembly, a housing, a main reducer driving tooth, a differential assembly, a main reducer driven tooth, a first gear gear assembly, a second gear gear assembly, a first gear driving gear, a second gear driving gear, a second gear transmission mechanism, and a reverse gear transmission mechanism. The first shaft, the intermediate shaft and the differential assembly are all arranged in parallel in the housing through bearings at both ends of each shaft. An integrally formed main reducer driving tooth is arranged in the middle of the intermediate shaft. The main reducer driving tooth is meshed with the main reducer driven tooth on the differential assembly for transmission. A first gear gear assembly and a second gear gear assembly are coaxially movably sleeved on the intermediate shaft located on both sides of the main reducer driving tooth. A first gear buffer tooth is arranged on the inner ring of the first gear gear assembly. A first gear engaging tooth is arranged on the outer ring of the first gear gear assembly. The gap between the assembly and the intermediate shaft is coaxially sleeved with a one-way overrunning clutch; the inner ring of the second-speed gear assembly is provided with a second-speed buffer tooth, and the outer ring of the second-speed gear assembly is provided with a second-speed gear engaging tooth; the first-speed driving gear and the second-speed driving gear formed in one piece are provided on the first shaft, the first-speed driving gear is meshed with the first-speed gear assembly for transmission, and the second-speed driving gear is meshed with the second-speed gear assembly for transmission; the second-speed transmission mechanism includes a left retaining ring, and the left retaining ring is coaxially sleeved on the intermediate shaft on the left side of the second-speed gear assembly; the first shaft and the intermediate shaft are matched with a reverse gear transmission mechanism that is transmission-connected to the first-speed gear assembly, and the reverse gear transmission mechanism includes a right retaining ring, and the right retaining ring is coaxially sleeved on the intermediate shaft on the right side of the first-speed gear assembly.

2. The electric two-speed transmission according to claim 1, characterized in that: The second-gear transmission mechanism also includes an electromagnetic driver, a left retaining spring, a left spring, a second-gear sliding engagement sleeve and a push-pull plate. The electromagnetic driver is installed on the inner wall of the shell with the intermediate shaft as the axis. The left side of the left retaining ring is sequentially sleeved with a left retaining spring, a left spring, a second-gear sliding engagement sleeve and a push-pull plate. The push-pull plate is tightly pressed against the bearing at the left end of the intermediate shaft.

3. The electric two-speed transmission according to claim 1, characterized in that: The reverse gear transmission mechanism also includes a friction wheel, a one-way clutch, a right retaining spring, a right spring, a first-gear sliding engagement sleeve, and first-gear sliding engagement teeth. The friction wheel is loosely sleeved on a shaft through a one-way clutch, and the right side of the right retaining ring is coaxially sleeved with a right retaining spring, a right spring and a first-gear sliding engagement sleeve in sequence. The outer ring of the first-gear sliding engagement sleeve is provided with first-gear sliding engagement teeth, and the friction wheel and the first-gear sliding engagement sleeve are slidingly and frictionally connected to each other along the circumferential surface.

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