44results about How to "Extended gliding distance" patented technology

The invention relates to a method for controlling take-off pull-up of an unmanned aerial vehicle based on robust servo. A control structure adopting robust servo is adopted, and the control structure comprises an inner loop and an outer loop; the inner loop is a pitch rate control loop, which adopts a pitch rate deviation integral and pitch rate damping control structure; and the outer loop is a pitch control loop, which adopts a pitch deviation proportion control structure. By adopting pitch proportion control for the outer loop and pitch rate integral control for the inner loop, the pitch rate control loop is added over the classical attitude pull-up control, thereby effectively solving the problems of hasty pull-up, excessive pitch adjustment and the like of the unmanned aerial vehicle in the take-off pull-up process, improving the response characteristics of longitudinal indicators such as pitch, angle of attack and the like of the unmanned aerial vehicle in the take-off pull-up process, and guaranteeing secure take-off of the unmanned aerial vehicle.

The invention provides an aircraft pathway running takeoff and landing assisting device, belongs to the field of machinery, and relates to the techniques of carrier aircraft takeoff and landing. An existing carrier aircraft landing assisting device in foreign military adopts the hydraulic arresting landing techniques, and an MK7 hydraulic arresting device is most typical especially. However, defects exist in the design of the MK7 hydraulic arresting device, and accident rate is high; it is as difficult as dancing on a blade for pilots to learn the technique, as they said. Finding another way, according to the aircraft pathway running takeoff and landing assisting device, the process of a carrier aircraft landing is divided into six steps, namely landing, hooking, binding, taxiing, decelerated taxiing and stopping; landing, hooking and binding are performed simultaneously, the left three steps are performed on the pathway in a limited manner, once hooking is successful, successful landing is guaranteed, the aircraft is prevented from deviating the pathway in the taxiing process to trigger an accident, and landing success rate is higher than that of the MK7 hydraulic arresting device. The aircraft pathway running takeoff and landing assisting device can also assist the carrier aircraft in taking off.

Disclosed in the invention is a planetary gear deceleration integrated motor comprising a housing part, a motor part, and a planetary gear deceleration part. The housing part consists of a motor shell, a main beam plate, and a reduction gearbox shell. The motor part installed in a cavity encircled by the motor shell and the main beam plate by a bearing contains a rotor shaft, a motor rotor, and a motor stator. The planetary gear deceleration installed in a cavity encircled by the reduction gearbox shell and the main beam plate by a bearing includes a sun wheel, a planet wheel, a planet carrier, an overturning clutch, and a power output shaft; the rotator shaft extends into the reduction gearbox shell to drive the sun wheel to make rotation; the sun wheel drives the planet wheel to rotate; the planet wheel drive the planet carrier to make rotation; the overturning clutch sleeves the power output shaft; the planet carrier drives the power output shaft to make rotation by the overturning clutch; and an annular gear arranged in the reduction gearbox shell is engaged with the planet wheel. The motor has advantages of small size, light weight, simple structure, high transmission efficiency, and low manufacturing cost.

The invention discloses a joint rotation structure which is used for achieving follow-up motions of an abdominal cavity anastomat. The structure comprises a trigger unit used for achieving first-angle rotation, a first transmission unit used for converting first-angle rotation generated by the triggering unit into first translation, a second transmission unit used for converting first translation into second-angle rotation, and an execution unit used for converting second-angle rotation of the second transmission unit into third-angle rotation corresponding to the first-angle rotation. Thus, the execution unit of the anastomat can be bent and steered by means of the joint rotation structure, the intermittent angle adjusting mode of the joint rotation structure is changed into a continuous angle stepless rotation mode, precision and application range of operating instruments are greatly improved, and requirements of required angles are met on the occasions where the operation environment is strict, operation difficulty is high and operation precision requirements are high.

The invention provides an engine control method and system and a vehicle. An engine comprises air inlet doors and air exhaust doors, the air inlet doors and the air exhaust doors correspond to cylinders and can be opened and closed independently. The engine control method comprises the steps of detecting the running mode of the vehicle, specifically, the running mode comprises a sliding mode and abraking mode; if the vehicle is in the sliding mode, controlling an oil atomizer to stop jetting oil and controlling the air inlet doors, the air exhaust doors and a throttle valve to be closed; andif the vehicle is in the braking mode, controlling the oil atomizer to stop jetting the oil, controlling the air inlet doors to be opened and controlling the air exhaust doors and the throttle valve to be closed. According to the method, when the vehicle is braked, the braking performance of the vehicle is improved, then running safety is ensured, the sliding distance of the vehicle is increased when the vehicle slides, and thus energy consumption is saved.

The invention discloses a locking ring type synchronizer with dissymmetric spline meshing teeth. The locking ring type synchronizer comprises a gear hub sleeving a transmission spindle, a slide bushing sleeves the gear hub, and combination tooth rings are arranged on two sides of the slide bushings respectively; a synchronization ring is arranged between each combination tooth ring and the slide bushing; the spline meshing teeth on the slide bushing, the combination tooth rings and the synchronization rings are all in dissymmetric structures. Since the spline meshing teeth on the slide bushing, the combination tooth rings and the synchronization rings are designed in the dissymmetric structures, the synchronizer is better in locking reliability, locking faces of the slide bushing and the synchronization rings are long in meshing time and large in combination area, and a favorable locking structure foundation is provided for a synchronization process; owing to the spline meshing teeth in the dissymmetric structures, sliding distance of the slide bushing on locking faces of the synchronization rings is increased, shifting speed difference caused by idle stroke generated when the slide bushing moves close to the combination tooth rings is reduced, large shifting speed difference results in impact of shifting, and accordingly secondary shifting impact after synchronization is alleviated.

The invention relates to a vehicle control method, a vehicle control device and a vehicle, and aims to increase a coasting distance of the automatic transmission vehicle and reduce a sense of abruptness generated when a driver presses an accelerator to accelerate during deceleration and downshifting. The vehicle control method comprises the steps of controlling a lock-up clutch of the vehicle to be in an open state during coasting of the vehicle so as to disconnect an engine of the vehicle from a transmission system, judging whether an accelerator pedal signal of the vehicle is detected, determining a gear position which matches a current vehicle speed when the accelerator pedal signal is detected, and controlling a state of the lock-up clutch and a torque response time of the engine according to the gear position so as to enable the vehicle to shift to the gear position and travel in the gear position.

An efficient energy-saving sliding controller of car is arranged between engine drive system and wheel drive system. It is composed of connecting axle, sliding external sleeve matched with connecting axle, internal gear for reverse running, monodirectional torsion driven clutch controller with sliding internal sleeve, several sliding block set between sliding internal and external sleeves, and transition cylinders (one between adjacent sliding block sets).

The invention relates to a novel drive axle capable of disconnecting half axles and a control method thereof. The novel drive axle is mainly composed of an upstream half axle, a downstream half axle,a bearing, a permanent magnet, a winding coil and an axle housing. One end of the upstream half axle is connected with a differential mechanism by virtue of a spline, and the other end of the upstreamhalf axle is opposite to one end of the downstream half axle and is fixed on the axle housing by virtue of the bearing; the one end of the downstream half axle is also fixed on the axle housing by virtue of a bearing, and the other end of the downstream half axle is connected with a hub; twisting force is transferred by electromagnetic force between the upstream half axle and the corresponding downstream half axle; and input current of the winding coil is controlled by a controller. Controllable disconnection of the half axles of the drive axle is realized, and separation and combination andconnection strength of the half axles can be automatically adjusted according to complete vehicle conditions. Meanwhile, since a manner of electromagnetic interaction force is adopted, the novel driveaxle does not have contact wear, is stable in performance, long in life, safe and reliable and does not need age-based maintenance.

The invention relates to a drive axle capable of disconnecting semi-axle and a control method thereof. The drive axle is mainly formed by an upstream semi-axle, a downstream semi-axle, a bearing, a permanent magnet and a winding coil. One end of the upstream semi-axle is connected with a differential mechanism by a spline, the other end is connected with one end of the downstream semi-axle by thebearing, the other end of the downstream semi-axle is connected with a hub, and torsion is transferred between the upstream semi-axle and the corresponding downstream semi-axle by electromagnetic force. Input current of the winding coil is controlled by a controller. The drive axle realizes controllable disconnection of the semi-axles of the drive axle, and can automatically adjust the disconnecting and connecting power of the semi-axles according to the working condition of the whole automobile, and meanwhile, by adopting a manner of electromagnetic acting force, contact abrasion is avoided,the performance is steady, the service life is long, aged-based maintenance is not needed, and the drive axle is safe and reliable.

The invention discloses an energy-saving combination power system of an engine of an automobile. The system is characterized in that an auxiliary clutch is arranged between a main clutch of the automobile and a speed changer; the main clutch is separated and the auxiliary clutch is combined when the automobile decelerates and slides; a primary air compressor, a driving wheel of a high-speed one-way gear and a driven wheel of the high-speed one-way gear are driven to a main air compressor, an air conditioning compressor and a power generator which are connected with an accessory transmission shaft by sliding inertia energy of the automobile to allow the main air compressor, the air conditioning compressor and the power generator to operate at a high speed for converting energy of the engine; power of the engine is transmitted to a sliding sleeve gear, a speed reducing gear, a driving wheel of a crankshaft one-way gear and a driven wheel of the crankshaft one-way gear which are connected with the accessory transmission shaft to drive an engine crankshaft to operate at a low speed, so that dragging resistance when the engine operates passively is reduced. When the engine accelerates to operate to drive the automobile, the auxiliary clutch is separated, the power of the engine is reduced by a crankshaft gear, a driving wheel of a speed reducing one-way gear, and a driven wheel of the speed reducing one-way gear, and then drives related accessories connected with the accessory transmission shaft to operate at a low speed, so that power consumption of the engine is reduced.

Provided is a power transmission mechanism of an energy-saving racing car. The energy-saving racing car comprises a car frame and a rear axle fixed on the car frame, and the power transmission mechanism comprises a drive part, a hub part, an electromagnetic control part and an end face jaw clutch. The drive part is axially and slidably sleeved at the left portion of the periphery of the rear axle, the hub part is axially positioned and rotatably installed at the right portion of the periphery of the rear axle, and the end face jaw clutch comprises a clutch driving jaw and a clutch driven jaw. The clutch driving jaw is sleeved on the right side of the drive part and is driven by the drive part to rotate, the clutch driven jaw is fixed on the left side of the hub part and is opposite to the clutch driving jaw, the electromagnetic control part is fixedly installed on the car frame, is fixedly connected with the drive part and drives the drive part to slide on the rear axle. The power transmission mechanism has the advantages of being long in sliding distance and good in energy-saving effect and can be applied to the energy-saving racing car.

The invention provides a centrifugal clutch comprising a clutch shell and a plurality of centrifugal shoe blocks arranged on the inner side of the clutch shell; each centrifugal shoe block comprises one outer circular arc surface and two end surfaces; moving blocks are embedded in or sleeve the outer circular arc surfaces of the centrifugal shoe blocks; the moving blocks can perform limited movement in the length directions of the centrifugal shoe blocks; return springs are installed between the moving blocks and the centrifugal shoe blocks; friction plates are pasted to the outer sides of the moving blocks; the end, facing the rotating direction, of each centrifugal shoe block is provided with a driving lever which is installed on the centrifugal shoe block via a hinge pin and a torsionsal spring; the upper end of each driving lever is provided with a rolling wheel or a bearing. When the moving blocks move in the rotating direction on the outer circular arc surfaces of the centrifugal shoe blocks, the moving blocks can push the driving levers to rotate around the hinge pins, so that the rolling wheels or the bearings on the driving levers protrude outward. The centrifugal shoe blocks and the clutch shell of the clutch can be separated timely after an engine is throttled down. The invention also provides a speed control system and a motorcycle employing the centrifugal clutch.

The invention discloses a multi-mode dual-motor two-gear gearbox for an electric automobile, relates to the technical field of electric automobiles, and aims to solve the technical problem that a common three-in-one electric drive assembly of an existing electric automobile cannot meet the requirements of dynamic property and economical efficiency of the automobile. In a multi-mode dual-motor two-gear gearbox of an electric automobile, a dual-motor structure in which motor rotor shafts are connected in series and integrated is adopted, a main drive motor is connected with a first-gear gear pair, and a second-gear gear pair transmits power to wheels through a differential mechanism. The auxiliary drive motor drives the direct gear pair through the one-way clutch and then transmits power to the wheels through the differential mechanism, the main drive motor and the auxiliary drive motor can independently drive the vehicle and can also transmit power to drive the wheels through power coupling, and the vehicle can have multiple working modes in the running process. Through switching of different working modes, the motor can operate in an efficient area as much as possible, the utilization rate of the motor is improved, power redundancy in matching is avoided, and the two-gear gearbox is free of power interruption during gear shifting.

The invention relates to a trigger signal control engine decompression device. The device comprises a control chip, a relay, a throttle position switch and a motor, wherein when an engine works, a signal of a trigger and a signal of the throttle position switch are input into the control chip in a balance mode, or when the throttle position switch is turned off, namely in a normal acceleration state, the control chip determines that the engine normally works and does not send any instruction, and the motor stops working; and under the condition that the engine is decelerated, namely when the signal of the trigger is higher than 1,200rpm and the throttle position switch is turned on, the control chip sends a signal to the relay, the relay is operated, the motor pushes a gas inlet valve to move downwards, compressed gas of the engine is completely discharged from the gas inlet valve, and the engine loses compression pressure and stops working, so that the sliding distance of a vehicle is increased, the suction of fuel oil is stopped, a carburetor engine can save oil by over 10 percent, and an obvious effect is achieved.

The present disclosure relates to a vehicle control method, device and vehicle to increase the gliding distance of an automatic transmission vehicle and reduce the frustration of the vehicle when the driver steps on the accelerator to accelerate during deceleration and downshifting. The vehicle control method of the present disclosure includes: during the coasting process of the vehicle, controlling the lock-up clutch of the vehicle to be in an open state, so that the engine and the transmission system of the vehicle are disconnected; Accelerator pedal signal; when the accelerator pedal signal is detected, determine the gear that matches the current vehicle speed; according to the gear, control the state of the lock-up clutch and the torque response time of the engine so that the The vehicle is switched to the gear for driving.

The invention provides a fuel economizer with sliding and automatic sliding forbidding functions. The fuel economizer comprises an automatic sliding forbidding mechanism and an overrun clutch; the automatic sliding forbidding mechanism comprises a clutch bearing seat, a clutch shell, a meshing wheel, a compression spring, a shifting fork, an air cylinder, an ejector rod, a return spring, a push rod and a meshing pin roller; the clutch bearing seat, the clutch shell, the meshing wheel and the shifting fork are installed on a spindle, the inclined surface of the ejector rod is in contact connection with the push rod, and the return spring and the meshing pin roller are installed on the push rod; the overrun clutch comprises a meshing pin roller, a large drum wheel and three sets of star wheels, the star wheels are installed in the large drum wheel and are fixed to the spindle, a sliding pin roller is installed on the star wheels, and the surface, combined with the meshing pin roller and the sliding pin roller, of the large drum wheel is provided with a regular concave surface. In the sliding process of a vehicle, connection between the vehicle and a driving system is automatically cut off, so that the sliding distance is increased, energy is saved, the function of automatically prohibiting sliding according to working conditions is achieved, and the original vehicle braking performance is improved.

The aircraft rail roll takeoff and landing auxiliary device of the invention belongs to the mechanical field and relates to carrier-based aircraft takeoff and landing technology. The landing aids of carrier-based aircraft in active service in foreign militaries mostly use hydraulic arresting landing technology, especially the MK7 hydraulic arresting device is the most typical. However, due to the shortcomings in the design of the MK7 hydraulic arresting device, the accident rate is relatively high, and it is difficult for pilots to master this technology. According to the pilots, it is like dancing on the tip of a knife. The present invention finds another way to divide the landing process of carrier-borne aircraft into six stages: landing, hooking, binding, taxiing, decelerating taxiing, and stopping. Landing, hooking, and binding occur simultaneously, and the latter three stages are all in the It is carried out on the track and is restricted. As long as the hook is successful, the successful landing will be guaranteed, and there will be no accidents caused by deviation from the runway during taxiing. The successful landing rate is higher than that of the MK7 hydraulic arresting device. The device of the invention can also help carrier-based aircraft to take off.

According to the motor and the electric vehicle provided with the motor, a sun gear (12) is fixedly assembled with an inner rotor (11) of the motor, an outer gear ring (10) is fixedly assembled with the inner wall of an outer rotor (2) of the motor, a planetary gear (13) is assembled on a planetary gear carrier (9), and a transmission sleeve (6) is arranged on the planetary gear carrier (9) and extends out of the outer rotor (2). The transmission sleeve (6) and the planetary gear carrier (9) are integrated or fixedly connected, a planetary gear carrier brake disc (4) is fixed at one end of thetransmission sleeve (6), extending out of the motor outer rotor (2), of the planetary gear carrier (9), and an end cover of the motor outer rotor (2) is assembled on the transmission sleeve (6) of the planetary gear carrier (9) through a bearing (8). One end cover is assembled with a motor central shaft (5) through a bearing.

The invention discloses a manual clutch and energy-saving coasting mechanism comprising a transmission shaft and a clutch mechanism, the clutch mechanism comprises a clutch push rod and a clutch block; a power output end of the transmission shaft is axially hollow, the transmission shaft is provided with a radial through groove, the axially hollow part is perforated with the radial through groove,the clutch block is embedded in the radial through groove, and the clutch push rod can penetrate the axially hollow part by the radial movement mode to be axially and fixedly connected with the clutch block; when in manual backing of a vehicle, the manual clutch and energy-saving coasting mechanism can easily realize the manual clutch, avoid the dead lock of a transmission mechanism, further facilitate the completion of the vehicle backing action, and facilitate the parking, the storing and the taking of the vehicle; when in coasting of the vehicle, the manual clutch and energy-saving coasting mechanism can fully utilize the power which is generated during the driving process of wheels, the coasting distance is long under the situation of the same power, thereby saving energy; furthermore, the invention has the advantages simple structure, small size and light weight, and is applicable to electric motorcycles and electric bicycles for use.

The invention discloses a tool for removing a tripmine quickly. The tool for removing the tripmine quickly comprises an anchor rod, wherein at least three anchor hooks bending backwards are arranged at the front end of the anchor rod; a digging rope is arranged at the rear end of the anchor rod; a barb for hooking a tripwire of the tripmine is arranged on one side of the middle part, corresponding to the rear end of the anchor rod, of each anchor hook; and a smooth structure for preventing the anchor hooks from being inserted into soil or hooking stones, weeds and shrubs is arranged at the tail end of each anchor hook. The tool for removing the tripmine quickly has a simple structure and is convenient to use; the tool is provided with the smooth structure, so that the anchor hooks can be prevented from being inserted into soil or hooking weeds or small shrubs in the process of retrieving the tool and the retrieving difficulty is reduced; the anchor rod is shot out by a crossbow or a spear gun, so the sliding distance of the anchor rod can be increased to 100 to 120 meters, namely, the mine-removing distance is increased, the mine-removing efficiency is improved and the safety of mine-removing operators is guaranteed.

The invention belongs to the technical field of drive equipment, and relates to a clutch. The clutch comprises an inner ring and an outer ring, wherein the inner ring is arranged in the outer ring; anannular cavity is formed between the inner ring and the outer ring; a wedge block mechanism is arranged in the annular cavity; the wedge block mechanism comprises a wedge block support seat and wedgeblock assemblies; a plurality of installation grooves are uniformly distributed in the wedge block support seat; the wedge block assemblies are arranged in the plurality of installation grooves whichare uniformly distributed at intervals separately; an elastic pressure ring is arranged at the outer side of each wedge block assembly; and the wedge block assemblies are tightly clamped onto the inner ring under the action of the elastic pressure rings. According to the clutch, through the design of an inclined arc surface at one end making contact with the inner ring, of each wedge block assembly, and the design of the elastic pressure ring at one end away from the corresponding inclined arc surface, of each wedge block assembly, the problems of torque decline, clamping stagnation and the like caused due to the eccentricity of an existing clutch on an inner ring and an outer ring, are solved; and the clutch has the advantages of being simple in manufacturing process, reliable in working, large in bearing torque, high in eccentric adaptability, long in service life and the like.

An efficient energy-saving sliding controller of car is arranged between engine drive system and wheel drive system. It is composed of connecting axle, sliding external sleeve matched with connecting axle, internal gear for reverse running, monodirectional torsion driven clutch controller with sliding internal sleeve, several sliding block set between sliding internal and external sleeves, and transition cylinders (one between adjacent sliding block sets).

The invention relates to the field of vehicle control, in particular to a method and device for reducing oil consumption in the vehicle sliding process. The method for reducing the fuel consumption in the vehicle sliding process comprises the following sequential steps that whether the whole vehicle condition of a vehicle meets a neutral gear sliding condition or not is judged; when it is determined that the whole vehicle condition meets the neutral gear sliding condition, a neutral gear sliding permission signal is sent to a transmission; and after the transmission receives the neutral sliding permission signal, whether neutral sliding is permitted or not is determined on the basis of the conditions of the transmission. The device for reducing the fuel consumption in the vehicle sliding process is used for executing the method for reducing the fuel consumption in the vehicle sliding process. According to the method and device for reducing the fuel consumption in the vehicle sliding process, the problem that in the related technology, the fuel cut-off time of an engine in the whole sliding process is short, and the fuel-saving effect generated by means of fuel cut-off in the related technology is limited can be solved.

The invention discloses an energy storage flywheel balance driving type scooter. A flywheel of the energy storage flywheel balance driving type scooter is installed on a front fork of the scooter. A large inner gear ring is arranged on the rim. A pinion is fixed on the flywheel and is meshed with the two front wheel rims. When the scooter slides, the rim drives the flywheel to rotate at a high speed to store energy so as to prolong the running distance of the scooter, and the running distance is about 20-50m which is several times that of a traditional scooter. The inertia of high-speed rotation of the flywheel generates a gyroscopic effect, so that the direction of the scooter is stable. The flywheel is replaced by a rotor of the disc type permanent magnet coreless motor, and the armature stator is only provided with a coil, so that the flywheel has the characteristic of no resistance in rotation and is absolutely matched with the scooter. Due to the application of the disc type permanent magnet coreless motor, resistance-free sliding is achieved, power-assisted sliding is also achieved, the continuous sliding function of the scooter is achieved under the condition that a battery and a power source are not used, and short-distance riding instead of walking is achieved.

The invention discloses a tool for removing a tripmine quickly. The tool for removing the tripmine quickly comprises an anchor rod, wherein at least three anchor hooks bending backwards are arranged at the front end of the anchor rod; a digging rope is arranged at the rear end of the anchor rod; a barb for hooking a tripwire of the tripmine is arranged on one side of the middle part, corresponding to the rear end of the anchor rod, of each anchor hook; and a smooth structure for preventing the anchor hooks from being inserted into soil or hooking stones, weeds and shrubs is arranged at the tail end of each anchor hook. The tool for removing the tripmine quickly has a simple structure and is convenient to use; the tool is provided with the smooth structure, so that the anchor hooks can be prevented from being inserted into soil or hooking weeds or small shrubs in the process of retrieving the tool and the retrieving difficulty is reduced; the anchor rod is shot out by a crossbow or a spear gun, so the sliding distance of the anchor rod can be increased to 100 to 120 meters, namely, the mine-removing distance is increased, the mine-removing efficiency is improved and the safety of mine-removing operators is guaranteed.

The invention relates to an energy-saving system for an engine valve of an automobile and tractor, comprising a valve plug, a valve cylinder, an engine cylinder, an air storage tank and a control circuit. The valve cylinder with the valve plug inside is fixed on the intake valve of the engine cylinder, and an electromagnetic The high-pressure and low-pressure air inlets of the valve, the high-pressure air inlets are connected to the brake pump and the air storage tank through pipelines, a solenoid valve is installed in the pipelines, the low-pressure air inlets are connected to filters through pipelines, and the valve plugs are provided with through-valve plugs in the middle The upper end of the valve plug is also connected to the bending connecting rod with a solenoid valve, and the plug piece connected to the solenoid valve is also set between the exhaust valve push rod and the rocker arm, and the solenoid valves are connected to The control circuit, the automobile tractor engine valve energy-saving system increases the sliding distance of the automobile with gear and the characteristics of inertial energy storage, saves fuel consumption, reduces mechanical loss, and makes the vehicle unnecessary to install an air pump or starter device, saving costs.

The invention discloses an energy-saving automatic speed control system of a light motorcycle. The energy-saving automatic speed control system comprises a centrifugal fly-block type clutch, a primary reduction gear, a secondary reduction gear, an automatic variable speed control device and a rear shaft assembly. The centrifugal fly-block type clutch is mounted on an output shaft of an engine; the rear shaft assembly and the primary reduction gear are mounted on a frame; and the primary reduction gear is connected with the centrifugal fly-block type clutch. The secondary reduction gear comprises a secondary chain, a variable speed chain wheel set, a chain wheel hub and an intermediate chain wheel, wherein the variable speed chain wheel set is mounted on the right end of a rear shaft in the rear shaft assembly through the chain wheel hub; the intermediate chain wheel is mounted on the left end of an intermediate shaft of the primary reduction gear; and the secondary chain connects the variable speed chain wheel set and the intermediate chain wheel. The automatic variable speed control device comprises an electronic control unit, an accelerator switch sensor, an electric push rod, an electric push rod displacement sensor, a variable speed steel wire and a derailleur. The electronic control unit is respectively connected with a speed measuring device, the accelerator switch sensor, the electric push rod and the electric push rod displacement sensor by using wires.