Electrically-driven two-gear speed reducer and control method thereof

Abstract

The invention relates to an electrically-driven two-gear speed reducer and a control method thereof. The two-gear speed reducer comprises an input shaft, a first-stage speed reduction gear set, a sun gear control shaft, a clutch, a brake, an NGW type planetary gear set, a third-stage speed reduction gear set and an output shaft. Wherein the primary reduction gear set comprises an input driving gear and an input driven gear; the NGW type planetary gear set comprises a sun gear, a planet gear, a gear ring and a planet carrier; the three-stage reduction gear set comprises an output driving gear and an output driven gear. A speed reducer formed by combining a parallel shaft speed reduction gear set and an NGW type planetary gear set has two driving gears, is free of power interruption in the gear shifting process and has a neutral gear and a parking gear; and meanwhile, the axial size is more compact. The adopted NGW type planetary gear set is the optimal choice in numerous planetary gear mechanisms, and is high in efficiency, small in size, simple in structure, convenient to manufacture and wide in application.

Description

Technical Field

[0001] The present invention relates to the technical field of speed reducers, and in particular to an electrically driven two-speed speed reducer and a control method thereof. Background Art

[0002] In the field of electric vehicles, most electric drive systems on the market currently consist of a drive motor + a single-speed reducer. However, with the increasing demand for vehicle performance, the demand for two-speed reducers is also gradually increasing. For example, for ordinary electric vehicles, it is necessary to reduce medium and high-speed energy consumption to increase the cruising range; for pure electric sports cars, higher acceleration and maximum speed are required; for large pure electric SUVs or pickups, greater low-speed wheel torque is required. A single-speed reducer with a fixed transmission ratio can no longer meet the needs of all the above working conditions. The two-speed reducer can effectively improve the power and economy of the entire vehicle through two speed ratios.

[0003] For ordinary electric vehicles, reducing medium and high speed energy consumption is the key to improving driving range. Due to its fixed transmission ratio, it is difficult for a single-speed reducer to achieve the best energy consumption performance in all speed ranges. Especially in the medium and high speed range, energy consumption may increase due to the inability to adapt to a wider range of working conditions. For high-performance models such as pure electric sports cars, they have extremely high requirements for acceleration and maximum speed. Single-speed reducers are limited by their transmission ratio range and may not provide sufficient torque amplification effect, thus affecting the acceleration performance of the vehicle. At the same time, when pursuing the highest speed, single-speed reducers may also be limited because they cannot match the high-speed characteristics of the motor. For large pure electric SUVs or pickup trucks, they usually require greater low-speed wheel torque to cope with complex road conditions and heavy load requirements. The torque amplification effect of a single-speed reducer at low speed is limited, and it may not meet the needs of these models under low-speed and high-torque working conditions. The emergence of two-speed reducers has become an effective solution. By introducing two speed ratios, the two-speed reducer can switch the speed ratio according to different working conditions and needs, thereby achieving a dual improvement in the power and economy of the whole vehicle.

[0004] In terms of power, a two-speed reducer can provide a larger torque amplification effect at low speeds to meet the needs of large or high-performance models under low-speed and high-torque conditions; at high speeds, it can switch to a smaller speed ratio to match the high-speed characteristics of the motor to achieve higher acceleration and maximum speed. In terms of economy, a two-speed reducer can reduce the energy consumption of the entire vehicle by optimizing the speed ratio matching. Especially in the medium and high speed sections, by selecting a suitable speed ratio to reduce the energy loss of the motor, the cruising range can be effectively improved. The application of two-speed reducers in the field of electric vehicles has significant advantages and necessity. It can not only improve the power and economy of the entire vehicle, but also better meet the needs of different models and working conditions. With the continuous advancement of electric vehicle technology and the increasing requirements of consumers for vehicle performance, two-speed reducers are expected to be more widely used and promoted in the field of electric vehicles.

[0005] With the development of reducer technology, there are two main schemes for two-speed reducers at present. One is parallel shaft two-stage reduction, using synchronizers to achieve the switching of two gears, such as the structure described in patent CN117404443A. This scheme has a relatively simple structure and high transmission efficiency, but there is power interruption in its shifting process; the other scheme is a combination of a parallel shaft reduction gear set and a planetary gear set, using the characteristics of the planetary gear set, through the control of the sun gear, planetary gear or ring gear by the clutch and brake to form two speed ratios. There is no power interruption in the shifting process of this scheme, but the existing schemes mostly use planetary gear sets with NW type, WW type and other structures, which are not compact enough, especially in the axial size, there is still room for optimization.

[0006] In the traditional technology, for example, the structure described in patent CN117404443A is relatively simple in structure and has high transmission efficiency, but there is power interruption in its shifting process; another solution is a combination of a parallel shaft reduction gear set and a planetary gear set, which utilizes the characteristics of the planetary gear set and controls the sun gear, planetary gear or ring gear through a clutch and a brake to form two speed ratios.

[0007] However, the current reducer structure mostly adopts planetary gear sets of NW type, WW type and other structures, which are not compact enough, especially in terms of axial dimension, and there is still room for optimization. Summary of the invention

[0008] Based on this, an electrically driven two-speed reducer and a control method thereof are provided.

[0009] The present invention provides an electrically driven two-speed reducer, the two-speed reducer comprising:

[0010] Input shaft, primary reduction gear set, sun gear control shaft, clutch, brake, NGW type planetary gear set, 3rd stage reduction gear set and output shaft;

[0011] Among them, the first-stage reduction gear set includes an input driving gear and an input driven gear; the NGW-type planetary gear set includes a sun gear, a planetary gear, a ring gear and a planet carrier; and the third-stage reduction gear set includes an output driving gear and an output driven gear.

[0012] The first-stage reduction gear set and the third-stage reduction gear set are both configured as helical cylindrical gears.

[0013] The NGW type planetary gear set realizes the speed ratio i2. Assuming the characteristic coefficient of the planetary gear set is α, when the sun gear and the ring gear have no relative rotation connection, the transmission ratio i2 of the planetary gear set is 1; when the sun gear is braked, the transmission ratio i2 of the planetary gear set is (1+α) / α.

[0014] The clutch includes a clutch active end and a clutch driven end, and the brake includes a brake active end and a brake driven end.

[0015] The input shaft is coaxially fixedly connected with the input driving gear; the input driven gear is coaxially fixedly connected with the ring gear; the output shaft is coaxially fixedly connected with the output driving gear and the planet carrier.

[0016] The input shaft driving gear meshes with the input shaft driven gear to form a first-stage reduction gear set to achieve a transmission ratio of i1.

[0017] The output driving gear meshes with the output driven gear to form a three-stage reduction gear set to achieve a transmission ratio of i3.

[0018] The sun gear control shaft is coaxially fixedly connected with the sun gear, the clutch driven end and the brake driven end; the gear ring is coaxially fixedly connected with the clutch active end; and the brake active end is fixedly connected with the housing.

[0019] The present invention also provides a vehicle, which uses the above-mentioned two-speed reducer and also includes a driving device, a differential device, a left half-shaft and a right half-shaft. The power of the driving device is transmitted to the wheels connected to the left half-shaft and the right half-shaft respectively through the two-speed reducer and the differential device.

[0020] The present invention also provides a control method for an electrically driven two-speed reducer, comprising the following steps:

[0021] The input shaft driving gear meshes with the input shaft driven gear to form a first-stage reduction gear set to achieve a transmission ratio of i1;

[0022] The sun gear, planetary gear, ring gear and planet carrier together form an NGW type planetary gear set; the power is input from the ring gear through the first-stage reduction gear set and output from the planet carrier, forming a secondary transmission ratio i2;

[0023] The clutch driving end is engaged with the clutch driven end, which can connect the sun gear and the ring gear without relative rotation. In this state, the transmission ratio of the planetary gear set is i2=1;

[0024] The active end of the brake is engaged with the driven end of the brake, which can stop the sun gear from rotating, that is, the speed is 0. In this state, the transmission ratio of the planetary gear set i2 = (1 + α) / α;

[0025] The output driving gear meshes with the output driven gear to form a three-stage reduction gear set to achieve a transmission ratio of i3;

[0026] Control the active end of the brake to engage with the driven end of the brake, and at the same time control the active end of the clutch to separate from the driven end of the clutch, so that the two-speed reducer can achieve a first-speed ratio of I 1st =i1×i2×i3=i1×(1+α) / α×i3;

[0027] The clutch active end is controlled to engage with the clutch driven end, and the brake active end is controlled to separate with the brake driven end. The two-speed reducer realizes the second-speed ratio I 2nd =i1×i2×i3=i1×i3;

[0028] Control the clutch active end and the clutch driven end to separate, and control the brake active end and the brake driven end to separate, so that the two-speed reducer can achieve neutral gear;

[0029] The clutch active end is controlled to engage with the clutch driven end, and the brake active end is controlled to engage with the brake driven end, and the two-speed reducer realizes the parking gear.

[0030] The above-mentioned electric drive two-speed reducer and control method thereof utilizes the combination of parallel shaft reduction gear set and NGW type planetary gear set to form a reducer with two driving gears and no power interruption during the gear shifting process, with one neutral gear and one parking gear; and at the same time, it has a more compact axial size. The NGW type planetary gear set used is the best choice among many planetary gear mechanisms, with high efficiency, small size, simple structure, easy manufacturing, and wide application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a schematic diagram of the relevant structure of a vehicle driving device of the present invention;

[0032] FIG. 2 is a schematic diagram of the structure of a two-speed reducer according to the present invention.

[0033] Among them, a, drive device; b, two-speed reducer; c, differential device; d, left half shaft; e, right half shaft; 1, input shaft; 2, first-stage reduction gear set; 3, sun gear control shaft; 4, clutch; 5, brake; 6, NGW type planetary gear set; 7, third-stage reduction gear set; 8, output shaft; 21, input driving gear; 22, input driven gear; 41, clutch active end; 42, clutch driven end; 51, brake active end; 52, brake driven end; 61, sun gear; 62, planetary gear; 63, ring gear; 64, planet carrier; 71, output driving gear; 72, output driven gear. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0037] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0039] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0040] As shown in Figure 1, the present invention discloses a vehicle, comprising a driving device a, a two-speed reducer b, a differential device c, a left half-shaft d, and a right half-shaft e. The power of the driving device a is transmitted to the wheels connected to the left half-shaft d and the right half-shaft e respectively through the two-speed reducer b and the differential device c.

[0041] Among them, any power source suitable for driving a vehicle can be used as the driving device a without special limitation.

[0042] Among them, an open differential and a dual clutch can both be used as the differential device c without special limitations.

[0043] Among them, the two-speed reducer b includes two sets of parallel shaft reduction gear sets and NGW type planetary gear sets; a shifting mechanism including a clutch and a brake. It has two driving gears and no power interruption during the shifting process, and has a neutral gear and a parking gear.

[0044] As shown in FIG2 , the present invention also discloses an electrically driven two-speed reducer, comprising an input shaft 1, a first-stage reduction gear set 2, a sun gear control shaft 3, a clutch 4, a brake 5, an NGW-type planetary gear set 6, a third-stage reduction gear set 7 and an output shaft 8;

[0045] Among them, the first-stage reduction gear set 2 and the third-stage reduction gear set 7 are usually configured as helical cylindrical gears, the first-stage reduction gear set 2 realizes a speed ratio i1, and the third-stage reduction gear set 7 realizes a speed ratio i3.

[0046] Wherein, the NGW type planetary gear set 6 realizes a speed ratio i2, and the characteristic coefficient of the planetary gear set is α, that is, the gear ratio of the ring gear 63 to the sun gear 61 is α, when the sun gear 61 and the ring gear 63 are not connected in relative rotation, that is, the speed difference between the sun gear 61 and the ring gear 63 is 0, the transmission ratio i2 of the planetary gear set 6 is 1; when the sun gear 61 is braked, that is, the speed of the sun gear 61 is 0, the transmission ratio i2 of the planetary gear set 6 is (1+α) / α;

[0047] The clutch 4 controls the separation or engagement of the sun gear 61 and the ring gear 63; the brake 5 controls the separation or engagement of the sun gear 61 and the housing;

[0048] When the clutch 4 and the brake 5 are released at the same time, the reducer is in neutral;

[0049] When the clutch 4 and the brake 5 are engaged at the same time, the speed reducer is in the parking gear;

[0050] When the clutch 4 is disengaged and the brake 5 is engaged, the speed reducer is in first gear;

[0051] When the clutch 4 is engaged and the brake 5 is disengaged, the speed reducer is in the second gear;

[0052] In addition, the clutch 4 and the brake 5 can be arranged in a coaxial nested structure to make the axial size more compact;

[0053] The two-speed reducer of the present invention adopts a parallel shaft reduction gear set and an NGW type planetary gear set, and has a compact structure and low cost.

[0054] In a specific embodiment, the two-speed reducer includes an input shaft 1, a first-stage reduction gear set 2, a sun gear control shaft 3, a clutch 4, a brake 5, an NGW-type planetary gear set 6, a third-stage reduction gear set 7, and an output shaft 8. The first-stage reduction gear set 2 includes an input driving gear 21 and an input driven gear 22; the clutch 4 includes a clutch driving end 41 and a clutch driven end 42; the brake 5 includes a brake driving end 51 and a brake driven end 52; the NGW-type planetary gear set 6 includes a sun gear 61, a planetary gear 62, a gear ring 63, and a planet carrier 64; the third-stage reduction gear set 7 includes an output driving gear 71 and an output driven gear 72.

[0055] In one embodiment, the input shaft 1 is coaxially fixedly connected to the input driving gear 21;

[0056] In one embodiment, the input shaft 1 and the input driving gear 21 are manufactured integrally;

[0057] In one embodiment, the input driven gear 22 is coaxially fixedly connected to the ring gear 63;

[0058] In one embodiment, the input driven gear 22 and the ring gear 63 are manufactured integrally;

[0059] In one embodiment, the input shaft driving gear 21 meshes with the input shaft driven gear 22 to form a first-stage reduction gear set 2 to achieve a transmission ratio i1;

[0060] In one embodiment, the sun gear 61, the planetary gear 62, the ring gear 63, and the planet carrier 64 together form an NGW type planetary gear set 6. The power is input from the ring gear 63 through the primary reduction gear set 2 and output from the planet carrier 64, forming a secondary transmission ratio i2. The sun gear control shaft 3 is coaxially fixedly connected with the sun gear 61, the clutch driven end 42 of the clutch 4, and the brake driven end 52 of the brake 5; the ring gear 63 is coaxially fixedly connected with the clutch active end 41 of the clutch 4;

[0061] The brake active end 51 of the brake 5 is fixedly connected to the housing;

[0062] In one embodiment, the clutch active end 41 of the clutch 4 is engaged with the clutch driven end 42, so that the sun gear 61 and the ring gear 63 are connected without relative rotation. In this state, the transmission ratio i2 of the planetary gear set 6 is 1;

[0063] In one embodiment, the brake active end 51 of the brake 5 is engaged with the brake driven end 52, which can stop the sun gear 61 from rotating, that is, the speed is 0. In this state, the transmission ratio i2 of the planetary gear set 6 is (1+α) / α;

[0064] In one embodiment, the output shaft 8 is coaxially fixedly connected with the output driving gear 71 and the planet carrier 64;

[0065] In one embodiment, the output shaft 8 is coaxially manufactured with the output driving gear 71 and the planet carrier 64;

[0066] In one embodiment, the output driving gear 71 meshes with the output driven gear 72 to form a three-stage reduction gear set 7 to achieve a transmission ratio i3;

[0067] In one embodiment, the brake active end 51 of the brake 5 is controlled to engage with the brake driven end 52, and the clutch active end 41 of the clutch 4 is controlled to disengage with the clutch driven end 42, so that the two-speed reducer realizes a first-speed ratio I 1st =i1×i2×i3=i1×(1+α) / α×i3;

[0068] In one embodiment, the clutch active end 41 of the clutch 4 is controlled to engage with the clutch driven end 42, and the brake active end 51 of the brake 5 is controlled to disengage with the brake driven end 52, so that the two-speed reducer realizes the second gear ratio I 2nd =i1×i2×i3=i1×i3;

[0069] In one embodiment, the clutch active end 41 of the clutch 4 is controlled to be separated from the clutch driven end 42, and the brake active end 51 of the brake 5 is controlled to be separated from the brake driven end 52, and the two-speed reducer realizes neutral gear;

[0070] Further, the clutch active end 41 of the clutch 4 is controlled to engage with the clutch driven end 42, and the brake active end 51 of the brake 5 is controlled to engage with the brake driven end 52, and the two-speed reducer realizes the parking gear;

[0071] The clutch and brake control states and gear positions are shown in the following table:

[0072] First gear Second gear Neutral Park Clutch status × √ × √ Brake status √ × × √

[0073] Among them, √-joining; ×-separation.

[0074] The invention utilizes a combination of a parallel shaft reduction gear set and an NGW type planetary gear set to form a reducer with two driving gears and no power interruption during the gear shifting process, a neutral gear and a parking gear; and a more compact axial dimension. The NGW type planetary gear set used is the best choice among many planetary gear mechanisms, with high efficiency, small size, simple structure, easy manufacturing, and wide application.

[0075] In one embodiment, the present invention further discloses a control method for an electrically driven two-speed reducer, comprising the following steps:

[0076] The input shaft driving gear 21 meshes with the input shaft driven gear 22 to form a first-stage reduction gear set 2 to achieve a transmission ratio i1;

[0077] The sun gear 61, the planetary gear 62, the ring gear 63, and the planet carrier 64 together form an NGW type planetary gear set 6; the power is input from the ring gear 63 through the primary reduction gear set 2 and output from the planet carrier 64, forming a secondary transmission ratio i2;

[0078] The clutch active end 41 of the clutch 4 is engaged with the clutch driven end 42, so that the sun gear 61 and the ring gear 63 are connected without relative rotation. In this state, the transmission ratio i2 of the planetary gear set 6 is 1;

[0079] The active end 51 of the brake 5 is engaged with the driven end 52 of the brake, which can stop the rotation of the sun gear 61, that is, the speed is 0. In this state, the transmission ratio i2 of the planetary gear set 6 is (1+α) / α;

[0080] The output driving gear 71 meshes with the output driven gear 72 to form a three-stage reduction gear set 7 to achieve a transmission ratio i3;

[0081] The brake active end 51 of the brake 5 is controlled to engage with the brake driven end 52, and the clutch active end 41 of the clutch 4 is controlled to disengage with the clutch driven end 42, so that the two-speed reducer realizes the first gear ratio I 1st =i1×i2×i3=i1×(1+α) / α×i3;

[0082] The clutch active end 41 of the clutch 4 is controlled to engage with the clutch driven end 42, and the brake active end 51 of the brake 5 is controlled to disengage with the brake driven end 52, so that the two-speed reducer realizes the second-speed ratio I 2nd =i1×i2×i3=i1×i3;

[0083] The clutch active end 41 of the clutch 4 is controlled to be separated from the clutch driven end 42, and the brake active end 51 of the brake 5 is controlled to be separated from the brake driven end 52, so that the two-speed reducer realizes neutral gear;

[0084] The clutch active end 41 of the clutch 4 is controlled to engage with the clutch driven end 42, and the brake active end 51 of the brake 5 is controlled to engage with the brake driven end 52, so that the two-speed reducer realizes the parking gear.

[0085] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0086] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An electrically driven two-speed reducer, characterized in that: The two-speed reducer comprises: An input shaft (1), a first-stage reduction gear set (2), a sun gear control shaft (3), a clutch (4), a brake (5), an NGW-type planetary gear set (6), a third-stage reduction gear set (7), and an output shaft (8); The first-stage reduction gear set (2) comprises an input driving gear (21) and an input driven gear (22); the NGW-type planetary gear set (6) comprises a sun gear (61), planetary gears (62), a ring gear (63) and a planet carrier (64); and the third-stage reduction gear set (7) comprises an output driving gear (71) and an output driven gear (72).

2. The two-speed reducer according to claim 1, characterized in that: The first-stage reduction gear set (2) and the third-stage reduction gear set (7) are both configured as helical cylindrical gears.

3. The two-speed reducer according to claim 2, characterized in that: The NGW type planetary gear set (6) realizes a speed ratio i2. Assuming that the characteristic coefficient of the planetary gear set is α, when the sun gear (61) and the ring gear (63) are not connected in relative rotation, the transmission ratio i2 of the planetary gear set (6) is 1; when the sun gear (61) is braked, the transmission ratio i2 of the planetary gear set (6) is (1+α) / α.

4. The two-speed reducer according to claim 3, characterized in that: The clutch (4) comprises a clutch active end (41) and a clutch driven end (42), and the brake (5) comprises a brake active end (51) and a brake driven end (52).

5. The two-speed reducer according to claim 1, characterized in that: The input shaft (1) is coaxially fixedly connected to the input driving gear (21); the input driven gear (22) is coaxially fixedly connected to the ring gear (63); and the output shaft (8) is coaxially fixedly connected to the output driving gear (71) and the planet carrier (64).

6. The two-speed reducer according to claim 1, characterized in that: The input shaft driving gear (21) meshes with the input shaft driven gear (22) to form a first-stage reduction gear set (2) to achieve a transmission ratio i1.

7. The two-speed reducer according to any one of claims 1 to 5, characterized in that: The output driving gear (71) meshes with the output driven gear (72) to form a three-stage reduction gear set (7) to achieve a transmission ratio i3.

8. The two-speed reducer according to claim 4, characterized in that: The sun gear control shaft (3) is coaxially fixedly connected to the sun gear (61), the clutch driven end (42), and the brake driven end (52); the ring gear (63) is coaxially fixedly connected to the clutch active end (41); and the brake active end (51) is fixedly connected to the housing.

9. A vehicle using the two-speed reducer according to any one of claims 1 to 8, characterized in that: It also includes a driving device (a), a differential device (c), a left half-shaft (d) and a right half-shaft (e). The power of the driving device (a) is transmitted to the wheels connected to the left half-shaft (d) and the right half-shaft (e) respectively through a two-speed reducer (b) and the differential device (c).

10. A control method for an electrically driven two-speed reducer, used for controlling the two-speed reducer according to any one of claims 1 to 8, characterized in that: The steps include: The input shaft driving gear (21) meshes with the input shaft driven gear (22) to form a first-stage reduction gear set (2) to achieve a transmission ratio i1; The sun gear (61), the planetary gear (62), the ring gear (63), and the planet carrier (64) together form an NGW type planetary gear set (6); power is input from the ring gear (63) through the primary reduction gear set (2) and output from the planet carrier (64), forming a secondary transmission ratio i2; The clutch active end (41) is engaged with the clutch driven end (42), so that the sun gear (61) and the ring gear (63) are connected without relative rotation. In this state, the transmission ratio i2 of the planetary gear set (6) is 1; The active end (51) of the brake is engaged with the driven end (52) of the brake, which can stop the rotation of the sun gear (61), that is, the rotation speed is 0. In this state, the transmission ratio i2 of the planetary gear set (6) is (1+α) / α; The output driving gear (71) meshes with the output driven gear (72) to form a three-stage reduction gear set (7) to achieve a transmission ratio i3; The brake active end (51) is controlled to engage with the brake driven end (52), and the clutch active end (41) is controlled to disengage with the clutch driven end (42), so that the two-speed reducer realizes the first gear ratio I 1st =i1×i2×i3=i1×(1+α) / α×i3; The clutch active end (41) is controlled to engage with the clutch driven end (42), and the brake active end (51) is controlled to disengage with the brake driven end (52), so that the two-speed reducer realizes the second-speed ratio I 2nd =i1×i2×i3=i1×i3; Controlling the clutch active end (41) and the clutch driven end (42) to separate, and controlling the brake active end (51) and the brake driven end (52) to separate, so that the two-speed reducer achieves neutral gear; The clutch active end (41) is controlled to engage with the clutch driven end (42), and the brake active end (51) is controlled to engage with the brake driven end (52), so that the two-speed reducer realizes the parking gear.

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