EMB driving, speed regulation and self-locking mechanism and method

Abstract

The invention discloses an EMB mechanism with driving, speed regulation and self-locking functions and a speed regulation method. Comprising two sets of worm and gear assemblies, an input shaft, an input side bevel gear, an output side bevel gear, an output shaft, a differential mechanism shell and a plurality of sun gears. The two worm and gear assemblies are connected to the differential mechanism shell and the input shaft respectively, the input shaft is coaxially and fixedly connected with the input side bevel gear, the output side bevel gear is coaxially and fixedly connected with the output shaft, and the input side bevel gear and the output side bevel gear are in meshing transmission connection through a plurality of sun gears. A sun gear is rotatably mounted on the differential housing. According to the mechanism, the driving, speed regulation and self-locking functions of the EMB can be effectively achieved, the independent driving function can be achieved through two sets of power, the coupling driving and locking functions can also be achieved, the function redundancy purpose is achieved, and the reliability of the EMB is fully guaranteed.

Description

Technical Field

[0001] The invention relates to a brake actuator for an automobile, in particular to an EMB mechanism and method with driving, speed regulating and self-locking functions. Technical Background

[0002] Traditional brake calipers are liquid-driven, with the brake master cylinder transferring the oil to the brake caliper through pipes. The entire process requires high-pressure sealing, but as the rubber seals age and wear, there will be risks of oil leakage and reduced braking force. In addition, the hydraulic transmission efficiency is only about 80%, and the pressure response rate is relatively low. The parking brake needs to be equipped with a separate braking mechanism and cannot be used in daily braking conditions. Summary of the invention

[0003] In order to solve the problems existing in the background technology, the present invention proposes an EMB mechanism and a speed regulation method with driving, speed regulation and self-locking functions, which are suitable for automobile electronic brake actuators.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] 1. An EMB mechanism with driving, speed regulation and self-locking functions:

[0006] It includes two sets of worm gear assemblies, an input shaft, an input side bevel gear, an output side bevel gear, an output shaft, a differential housing and a plurality of sun gears; the two sets of worm gear assemblies are respectively connected to the differential housing and the input shaft, the input shaft and the input side bevel gear are coaxially fixedly connected, the output side bevel gear and the output shaft are coaxially fixedly connected, the input side bevel gear and the output side bevel gear are meshingly connected through a plurality of sun gears, and the sun gears are rotatably mounted on the differential housing.

[0007] The input side bevel gear, the output side bevel gear and a plurality of sun gears are all installed in the differential housing.

[0008] One end of the differential housing is fixedly and sealedly connected to the wheel end face of a driven worm wheel of a worm gear assembly, and the other end is rotatably sleeved on the output shaft through a bearing.

[0009] Each worm gear assembly includes a worm and a driven worm wheel. The worm is connected to a power source. The worm and the driven worm wheel mesh with each other to form a worm gear pair. The driven worm wheel is coaxially rotatable / coaxially fixedly mounted on the input shaft.

[0010] The driven worm wheel of one set of worm gear assemblies is coaxially fixedly connected to the input shaft, and the driven worm wheel of the other set of worm gear assemblies is rotatably coaxially sleeved on the input shaft and is fixedly connected to the differential housing.

[0011] The plurality of sun gears are arranged between the input side bevel gear and the output side bevel gear and are arranged along the circumferential direction. One side of each sun gear is meshed with the input side bevel gear, and the other side is meshed with the output side bevel gear.

[0012] The plurality of sun gears are evenly spaced along the circumferential direction and rotatably mounted on the inner wall of the differential housing, and each sun gear is hingedly mounted on the inner wall of the differential housing.

[0013] The present invention is driven by two sets of worm gear transmission mechanisms with independent self-locking functions, and can cooperate with each other to achieve speed reduction and torque increase. The torque and speed are coupled through the sun gear in the transmission housing, and the rotational torque is transmitted to the ball screw inside the caliper through the output shaft, thereby driving the piston movement in the caliper to realize EMB brake clamping, holding and brake release actions.

[0014] The transmission mechanisms corresponding to the two sets of worm gear assemblies have independent driving and self-locking functions. Each set of worm gear transmission mechanisms can amplify the rotational torque input by the worm and transmit it to the output shaft; when there is no power input to the two sets of worm gears, the self-locking function of the worm gear will keep the EMB in a released, non-braking or clamping locked state.

[0015] The rotational torque and speed transmitted by the two sets of worm gears are coupled to each other through the sun gear in the transmission housing, and work together to achieve the speed and torque regulation function, expanding the output shaft rotation speed range, reducing the difficulty and requirements of motor control, and the power connection is linear and smooth.

[0016] 2. A speed regulation method, wherein the two sets of worm gear assemblies in the EMB mechanism are divided into a first set of worm gear assemblies and a second set of worm gear assemblies;

[0017] The first set of worm gear assembly includes a first worm and a first driven worm wheel, and the first driven worm wheel is coaxially sleeved and connected with the input shaft; the second set of worm gear assembly includes a second worm and a second driven worm wheel, and the second driven worm wheel is coaxially fixedly connected with the differential housing to form a whole, and the second driven worm wheel is coaxially sleeved and movably sleeved with the input shaft;

[0018] The speed regulation method uses four speed regulation modes to adjust the operation under different conditions:

[0019] A. When it is necessary to control the output shaft to output power at a lower speed and a larger torque, the first set of worm gear assembly is driven by external power, and the second set of worm gear assembly is not driven by external power:

[0020] The first worm of the first worm gear assembly rotates forwardly under external power, driving the first driven worm gear, the input shaft and the input side bevel gear to rotate as a whole, and the output side bevel gear and the output shaft to rotate through the transmission of the sun gear;

[0021] B. When it is necessary to control the output shaft to output power at a higher speed and a smaller torque, the second set of worm gear assembly is driven by external power, and the first set of worm gear assembly is not driven by external power:

[0022] The second worm of the second worm gear assembly rotates forwardly under the external power, driving the second driven worm gear and the differential housing to rotate as a whole, while the first driven worm gear, the input shaft and the input side bevel gear of the first worm gear assembly do not rotate as a whole, and the multiple sun gears rotate around the axis of the output shaft to drive the output side bevel gear and the output shaft to rotate;

[0023] C. When it is necessary to control the output shaft to output power at a higher speed, both the first set of worm gear assemblies and the second set of worm gear assemblies are driven by external power:

[0024] The first worm of the first worm gear assembly and the second worm of the second worm gear assembly are both rotated forward by external power, and are transmitted to the sun gear for power superposition, and then the output side bevel gear and the output shaft are driven to rotate at a higher speed through the transmission of the sun gear;

[0025] D. When it is necessary to output power at zero speed or quickly switch the output shaft to forward / reverse rotation, the first set of worm gear assembly and the second set of worm gear assembly are driven by external power:

[0026] The first worm of the first worm gear assembly and the second worm of the second worm gear assembly are respectively rotated forward / reversely by external power, and both are transmitted to the sun gear for power speed subtraction. The subtracted power drives the output side bevel gear and the output shaft to rotate forward / reverse at zero speed or quickly switch the output shaft through the transmission of the sun gear.

[0027] The speed regulation method also includes: when a quick response is required to reach the required output speed, the second set of worm gear components is first controlled to be driven by external power and the first set of worm gear components is not driven by external power, so that the power speed output by the output shaft is quickly adjusted to the required output speed, and then the first set of worm gear components and the second set of worm gear components are switched to be driven by external power together, and the speed of the first set of worm gear components acting on the output shaft is gradually increased, while the speed of the second set of worm gear components acting on the output shaft is reduced and increased, so that the torque output of the output shaft is increased while the power speed output of the output shaft remains unchanged, thereby achieving torque increase at the same speed.

[0028] The technical problems and economic benefits to be solved by the present invention are:

[0029] (1) The double worm gear and sun gear structure can independently transmit rotational torque and also perform coupled speed regulation;

[0030] (2) The self-locking functions of the double worm gear structure are independent of each other.

[0031] The mechanism of the present invention can effectively realize the driving, speed regulation and self-locking functions of the EMB, and the two sets of power can realize independent driving functions, and can also perform coupled driving and locking functions to achieve the purpose of functional redundancy and fully ensure the reliability of the EMB. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The innovative structure is further described below in conjunction with the accompanying drawings and specific implementations:

[0033] Figure 1 It is a schematic diagram of the structure of the present invention.

[0034] Figure 2 This is the first set of worm gear assembly independently driven to transmit power diagram of the present invention.

[0035] Figure 3 This is a diagram of the second set of worm gear assemblies independently driving and transmitting power in the present invention.

[0036] Figure 4 The present invention is a diagram of two sets of worm gear assemblies coupled to drive and transmit power.

[0037] Figure 5 It is a schematic diagram of the structure of the present invention.

[0038] Figure 6 It is an overall cross-sectional view of the present invention.

[0039] Figure 7 It is a structural diagram of the first set of worm gear assembly of the present invention.

[0040] Figure 8 It is the structural diagram of the input shaft of the present invention.

[0041] Fig. 9 It is a structural diagram of the second set of worm gear assembly of the present invention.

[0042] Fig.10 It is the structural diagram of the output shaft of the present invention.

[0043] In the figure: a first worm 1, a first driven worm wheel 2, a second worm 3, a second driven worm wheel 4, an input shaft 5, an input-side bevel gear 6, an output-side bevel gear 7, an output shaft 8, a differential housing 9, and a sun gear 10. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0045] like Figure 1As shown, it includes two sets of worm gear assemblies, an input shaft 5, an input side bevel gear 6, an output side bevel gear 7, an output shaft 8, a differential housing 9 and a plurality of sun gears 10; the two sets of worm gear assemblies are respectively connected to the differential housing 9 and the input shaft 5, the input shaft 5 and the input side bevel gear 6 are coaxially fixedly connected, the output side bevel gear 7 and the output shaft 8 are coaxially fixedly connected, the input side bevel gear 6 and the output side bevel gear 7 are coaxially spaced, the input side bevel gear 6 and the output side bevel gear 7 are meshingly connected through a plurality of sun gears 10, and the sun gears 10 are rotatably hingedly mounted on the differential housing 9.

[0046] In the whole mechanism, the motor drives the worms in the two worm gear assemblies to rotate, and then the output shaft 8 outputs power.

[0047] The input-side bevel gear 6 , the output-side bevel gear 7 and a plurality of sun gears 10 are all installed in the differential housing 9 .

[0048] like Figure 6 As shown, one end of the differential housing 9 is fixedly sealed and connected to the wheel end face of a driven worm wheel of a worm gear assembly to form an integral structure; and the other end is rotatably mounted on the output shaft 8 through a bearing.

[0049] Each worm gear assembly includes a worm and a driven worm wheel. The worm is connected to the power source, and the worm and the driven worm wheel are meshed to form a worm gear pair. Figure 8 As shown, the driven worm gear is coaxially rotatable / coaxially fixedly mounted on the input shaft 5 .

[0050] The power source is, for example, a motor.

[0051] The worm gear pairs of the two sets of worm gear assemblies are arranged in parallel and in parallel with each other.

[0052] The driven worm wheel of one set of worm gear assemblies is coaxially fixedly connected to the input shaft 5 , and the driven worm wheel of the other set of worm gear assemblies is rotatably coaxially sleeved on the input shaft 5 and fixedly connected to the differential housing 9 .

[0053] A plurality of sun gears 10 are arranged between the input bevel gear 6 and the output bevel gear 7 and arranged in the circumferential direction. One side of each sun gear 10 meshes with the input bevel gear 6 and the other side meshes with the output bevel gear 7 .

[0054] A plurality of sun gears 10 are evenly spaced along the circumferential direction and rotatably mounted on the inner wall of the differential housing 9. Each sun gear 10 is hingedly mounted on an axle fixed to the inner wall of the differential housing 9, that is, each sun gear 10 is movably mounted on a radially arranged axle fixed to the inner wall of the differential housing 9.

[0055] like Figure 8As shown, one end of the input shaft is connected to the bearing on the caliper housing and can rotate axially. There is also a spline on the input shaft near this end. The first driven worm gear 2 is connected to the input shaft through the spline to transmit power. The other end of the input shaft is provided with bevel teeth and fully extends into the differential housing, meshing with the three sun gears inside the differential housing.

[0056] One end of the first worm 1 is connected to the external motor, and the other end is connected to the bearing on the caliper housing, and can rotate axially. The middle part of the first worm 1 is provided with thread teeth, which is used to engage with the first driven worm wheel 2. When the external motor transmits the torque speed to the first worm 1, the first worm 1 drives the first driven worm wheel 2 to reduce speed and increase torque, and transmits the power to the input shaft through the spline. The input shaft then passes through the bevel gear and the sun gear in the differential housing, and finally transmits the power to the output shaft.

[0057] One end of the second worm 3 is connected to the external motor, and the other end is connected to the bearing on the caliper housing, and can rotate axially. The middle part of the second worm 3 is provided with thread teeth for meshing with the second driven worm wheel 4. When the torque speed of the external motor is transmitted to the second worm 3, the second worm 3 drives the second driven worm wheel 4 to reduce speed and increase torque, and transmits power to the output shaft through the sun gear in the differential housing.

[0058] The worm teeth of the first driven worm wheel 2 mesh with the thread teeth of the first worm 1, which can transmit power and self-lock; the socket teeth of the second driven worm wheel 4 mesh with the thread teeth of the second worm 3, which can transmit power and self-lock. The second driven worm wheel 4 is rigidly connected to the transmission housing (or an integrated structure), and three sun gears are evenly distributed on the circumference of the transmission housing, which mesh with the bevel gears on the input and output shafts for torque and speed coupling and power transmission.

[0059] like Fig. 9 As shown, a spline is provided at the other end of the output shaft 8, and the output shaft 8 is connected to the ball screw in the brake caliper through the spline to transmit power.

[0060] In specific implementation, Figure 5 and Figure 6 As shown, the worm gear assembly includes two independent sets and three sun gears 10, namely a first worm 1 and a first driven worm wheel 2, a second worm 3 and a second driven worm wheel 4.

[0061] Specifically, Figure 7 As shown, the first worm gear assembly includes a first worm 1 and a first driven worm wheel 2. The first driven worm wheel 2 and the input shaft 5 are coaxially connected to form a whole. There is no connection between the first driven worm wheel 2 and the differential housing 9. Fig. 9As shown, the second worm gear assembly includes a second worm 3 and a second driven worm wheel 4. The second driven worm wheel 4 and the differential housing 9 are coaxially fixedly connected to form a whole. At the same time, the second driven worm wheel 4 and the input shaft 5 are coaxially movably mounted.

[0062] The first driven worm gear 2 is sleeved on the spline at one end of the input shaft 5, and the other end of the input shaft 5 is provided with bevel teeth as the input side bevel gear 6. The input side bevel gear 6 at this end is sleeved in the differential case 9 and meshes with the three sun gears 10 in the differential case 9. The second driven worm gear 4 is rigidly connected to the differential case 9 to form an integrated structure. One end of the output shaft 8 is provided with bevel teeth as the output side bevel gear 7. The output side bevel gear 7 at this end is also sleeved in the differential case 9 and meshes with the three sun gears in the differential case 9. The other end of the output shaft 8 is provided with a spline, which can be connected to the ball screw inside the brake caliper of the brake for power transmission.

[0063] When the brake caliper needs to be clamped or released to drive the piston to move, the power transmission is specifically divided into:

[0064] When the external power only drives the first worm 1 to rotate and the second worm 3 does not rotate, the power will be transmitted through the first driven worm gear 2 to reduce the speed and increase the torque, and the speed and the amplified torque will be transmitted to the ball screw through the input shaft 5, the sun gear 9 and the output shaft 8 to drive the piston to move;

[0065] When the external power only drives the second worm 3 to rotate and the first worm 1 does not rotate, the power will be transmitted through the second driven worm gear 4 to reduce the speed and increase the torque, and the speed and the amplified torque will be transmitted to the ball screw through the differential housing 9, the sun gear 10, and the output shaft 8 to drive the piston to move;

[0066] When external power drives the first worm 1 and the second worm 3 to rotate at the same time, the power will be transmitted through the first driven worm gear 2 and the second driven worm gear 4 to reduce the speed and increase the torque. The speed and the amplified torque are respectively transmitted through the input shaft 5 and the differential case 9, and torque coupling is performed at the sun gear 10. The torque is then transmitted to the ball screw through the output shaft 8 to drive the piston to move.

[0067] When the brake caliper needs to be clamped and locked or kept released without braking, when the external power stops driving the worm to rotate, the first worm 1 and the second worm 3 will be locked with the first driven worm gear 2 and the second driven worm gear 4, which will prevent the output shaft 8 from rotating and further prevent the piston from moving, thereby achieving the caliper clamping and locking or releasing without braking function.

[0068] The two sets of worm gear assemblies in the EMB mechanism are divided into a first set of worm gear assemblies and a second set of worm gear assemblies;

[0069] The first set of worm gear assembly includes a first worm 1 and a first driven worm wheel 2, and the first driven worm wheel 2 is coaxially sleeved with the input shaft 5; the second set of worm gear assembly includes a second worm 3 and a second driven worm wheel 4, and the second driven worm wheel 4 is coaxially fixedly connected with the differential housing 9 to form a whole, and the second driven worm wheel 4 is coaxially sleeved with the input shaft 5;

[0070] The speed regulation method uses four speed regulation modes to adjust the operation under different conditions:

[0071] A. When it is necessary to control the output shaft 8 to output power at a lower speed and a larger torque, such as Figure 2 As shown, the first set of worm gear assembly is driven by external power, and the second set of worm gear assembly is not driven by external power:

[0072] The first worm 1 of the first worm gear assembly rotates forwardly under the external power, driving the first driven worm gear 2, the input shaft 5 and the input side bevel gear 6 to rotate as a whole, and the output side bevel gear 7 and the output shaft 8 are driven to rotate at the transmission ratio of the first worm gear assembly through the transmission of the sun gear 10; the second driven worm gear 4 of the second worm gear assembly and the differential case 9 do not rotate as a whole.

[0073] In this case, since the transmission of the first set of worm gear components driven by the input shaft 5, sun gear 10, and output shaft 8 is relatively small, under the same external power input speed, the output shaft 8 has a larger torque and a smaller speed, which can be used to achieve torque increase and speed reduction for high-intensity braking.

[0074] B. When it is necessary to control the output shaft 8 to output power at a higher speed and smaller torque, such as Figure 3 As shown, the second set of worm gear assembly is driven by external power, and the first set of worm gear assembly is not driven by external power:

[0075] The second worm 3 of the second worm gear assembly rotates forwardly under the external power, driving the second driven worm gear 4 and the differential housing 9 to rotate as a whole, and the first driven worm gear 2, the input shaft 5 and the input side bevel gear 6 of the first worm gear assembly do not rotate as a whole, and the multiple sun gears 10 rotate around the axis of the output shaft 8 to drive the output side bevel gear 7 and the output shaft 8 to rotate at the transmission ratio of the second worm gear assembly to the differential housing 9 and the sun gear 10;

[0076] In this case, since the transmission of the second worm gear assembly driven by the differential housing 9 and the sun gear 10 is relatively small, under the same external power input speed, the torque is small and the speed is large, which can be used to achieve speed increase and torque reduction for rapid braking response.

[0077] C. When it is necessary to control the output shaft 8 to output power at a higher speed, such as Figure 4 As shown, the first set of worm gear assemblies and the second set of worm gear assemblies are both driven by external power:

[0078] The first worm 1 of the first worm gear assembly and the second worm 3 of the second worm gear assembly are both rotated forward by external power, and are transmitted to the sun gear 10 for power speed superposition. The transmission ratios of the two sets of worm gear assemblies are superimposed, and then the output side bevel gear 7 and the output shaft 8 are driven by the transmission of the sun gear 10 to rotate at a higher speed than the sum of the transmission ratios of the two sets of worm gear assemblies;

[0079] In this case, due to the combined effect of the two worm gear assemblies to superimpose the transmission ratio, under the same external power input speed, the speed is maximum and the torque also increases, which can be used to achieve speed increase and torque increase.

[0080] When it is necessary to output power at zero speed or to quickly switch the output shaft 8 to forward / reverse rotation, both the first set of worm gear assembly and the second set of worm gear assembly are driven by external power to work:

[0081] The second worm 3 of the second worm gear assembly and the first worm 1 of the first worm gear assembly are respectively rotated forward and reversely by external power, and both are transmitted to the sun gear 10 for power speed subtraction. The transmission ratios of the two sets of worm gear assemblies are subtracted, and the output side bevel gear 7 and the output shaft 8 are driven by the transmission of the sun gear 10 to rotate forward / reverse at zero speed or quickly switch the output shaft 8 at a transmission ratio difference between the two sets of worm gear assemblies.

[0082] In this case, since the transmission ratios of the two worm gear assemblies are subtracted through the joint action of the input shaft 5, the differential housing 9, and the sun gear 10, under the same external power input speed, the speed is in the middle and the torque is also in the middle, which can be used to achieve speed and torque adjustment, improve the control accuracy of the brake, achieve more precise adjustment, and prevent the brake from locking.

[0083] For example, the speed control method also includes:

[0084] When the brake is started and a quick response is required to reach the required output speed, the second set of worm gear assemblies is first controlled to be driven by external power and the first set of worm gear assemblies are not driven by external power, so that the power speed output by the output shaft 8 is quickly adjusted to the required output speed, and then the first set of worm gear assemblies and the second set of worm gear assemblies are switched to be driven by external power together, and the speed of the first set of worm gear assemblies acting on the output shaft 8 is gradually increased, while the speed of the second set of worm gear assemblies acting on the output shaft 8 is reduced and increased, so that the torque output by the output shaft 8 is increased while the power speed output by the output shaft 8 remains unchanged, thereby achieving torque increase at the same speed.

Claims

1. An EMB mechanism with driving, speed regulation and self-locking functions, characterized in that: The invention comprises two sets of worm gear assemblies, an input shaft (5), an input side bevel gear (6), an output side bevel gear (7), an output shaft (8), a differential housing (9) and a plurality of sun gears (10); the two sets of worm gear assemblies are respectively connected to the differential housing (9) and the input shaft (5); the input shaft (5) and the input side bevel gear (6) are coaxially fixedly connected; the output side bevel gear (7) and the output shaft (8) are coaxially fixedly connected; the input side bevel gear (6) and the output side bevel gear (7) are meshingly connected through a plurality of sun gears (10); and the sun gears (10) are rotatably mounted on the differential housing (9).

2. The EMB mechanism with driving, speed regulation and self-locking functions according to claim 1, characterized in that: The input side bevel gear (6), the output side bevel gear (7) and a plurality of sun gears (10) are all installed in a differential housing (9).

3. The EMB mechanism with driving, speed regulation and self-locking functions according to claim 1, characterized in that: One end of the differential housing (9) is fixedly sealedly connected to the wheel end face of a driven worm wheel of a worm gear assembly, and the other end is rotatably sleeved on the output shaft (8) via a bearing.

4. The EMB mechanism with driving, speed regulation and self-locking functions according to claim 1, characterized in that: Each worm gear assembly comprises a worm and a driven worm wheel. The worm is connected to a power source. The worm and the driven worm wheel mesh with each other to form a worm gear pair. The driven worm wheel is coaxially rotatable / coaxially fixedly sleeved on the input shaft (5).

5. The EMB mechanism with driving, speed regulation and self-locking functions according to claim 1, characterized in that: The driven worm wheel of one set of worm gear assemblies is coaxially fixedly connected to the input shaft (5), and the driven worm wheel of the other set of worm gear assemblies is rotatably coaxially sleeved on the input shaft (5) and is fixedly connected to the differential housing (9).

6. The EMB mechanism with driving, speed regulation and self-locking functions according to claim 1, characterized in that: The plurality of sun gears (10) are arranged between the input side bevel gear (6) and the output side bevel gear (7) and are arranged in the circumferential direction; one side of each sun gear (10) is meshed with the input side bevel gear (6) and the other side is meshed with the output side bevel gear (7).

7. The EMB mechanism with driving, speed regulation and self-locking functions according to claim 1, characterized in that: The plurality of sun gears (10) are evenly spaced along the circumferential direction and rotatably mounted on the inner wall of the differential housing (9), and each sun gear (10) is hingedly mounted on the inner wall of the differential housing (9).

8. A speed regulation method applied to the EMB mechanism according to any one of claims 1 to 7, characterized in that: The two sets of worm gear assemblies in the EMB mechanism are divided into a first set of worm gear assemblies and a second set of worm gear assemblies; The first set of worm gear assembly comprises a first worm (1) and a first driven worm wheel (2), and the first driven worm wheel (2) and the input shaft (5) are coaxially sleeved and connected; the second set of worm gear assembly comprises a second worm (3) and a second driven worm wheel (4), and the second driven worm wheel (4) and the differential housing (9) are coaxially fixedly connected to form a whole, and the second driven worm wheel (4) and the input shaft (5) are coaxially sleeved and movable; The speed regulation method uses four speed regulation modes to adjust the operation under different conditions: A. When it is necessary to control the output shaft (8) to output power at a lower speed and a larger torque, the first set of worm gear assembly is driven by external power, and the second set of worm gear assembly is not driven by external power: The first worm (1) of the first worm gear assembly rotates in the positive direction under the influence of external power, driving the first driven worm gear (2), the input shaft (5) and the input side bevel gear (6) to rotate as a whole, and driving the output side bevel gear (7) and the output shaft (8) to rotate through the transmission of the sun gear (10); B. When it is necessary to control the output shaft (8) to output power at a higher speed and a smaller torque, the second set of worm gear assembly is driven by external power, and the first set of worm gear assembly is not driven by external power: The second worm (3) of the second worm gear assembly rotates in the positive direction under the influence of external power, driving the second driven worm gear (4) and the differential housing (9) to rotate as a whole, while the first driven worm gear (2), the input shaft (5) and the input side bevel gear (6) of the first worm gear assembly do not rotate as a whole, and the plurality of sun gears (10) rotate around the axis of the output shaft (8) to thereby drive the output side bevel gear (7) and the output shaft (8) to rotate; C. When it is necessary to control the output shaft (8) to output power at a higher speed, both the first set of worm gear assembly and the second set of worm gear assembly are driven by external power to work: The first worm (1) of the first worm gear assembly and the second worm (3) of the second worm gear assembly are both rotated in the positive direction by external power, and are both transmitted to the sun gear (10) for power superposition, and then the output side bevel gear (7) and the output shaft (8) are driven to rotate at a higher speed through the transmission of the sun gear (10); D. When it is necessary to output power at zero speed or switch the output shaft (8) to forward / reverse rotation, both the first set of worm gear assembly and the second set of worm gear assembly are driven by external power to work: The first worm (1) of the first worm gear assembly and the second worm (3) of the second worm gear assembly are respectively rotated forward / reversely by external power, and both are transmitted to the sun gear (10) for power speed subtraction. The subtracted power is transmitted through the sun gear (10) to drive the output side bevel gear (7) and the output shaft (8) to rotate at zero speed or switch the output shaft (8) forward / reverse.

9. The speed regulation method according to claim 8, characterized in that: The speed regulation method further comprises: when a quick response is required to reach a desired output speed, the second set of worm gear components is first controlled to be driven by external power and the first set of worm gear components is not driven by external power, so that the speed of the power output by the output shaft (8) is quickly adjusted to the desired output speed, and then the first set of worm gear components and the second set of worm gear components are switched to be driven by external power together, and the speed of the first set of worm gear components acting on the output shaft (8) is gradually increased, while the speed of the second set of worm gear components acting on the output shaft (8) is reduced and increased, so that the torque output by the output shaft (8) is increased while the speed of the power output by the output shaft (8) remains unchanged, thereby achieving torque increase at the same speed.

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