Electric gear shifting system based on direct-current brush gear motor

Abstract

The invention discloses an electric gear shifting system based on a direct-current brush gear motor, and relates to the technical field of racing cars, the electric gear shifting system based on the direct-current brush gear motor comprises a power control device, a power output device and a power transmission device; the power control device is used for receiving a gear shifting instruction, generating a motor control signal and cooperating with a whole vehicle ECU (an electronic control unit and a general controller of a vehicle), and comprises a signal input module used for receiving gear signals sent by a driver, and the gear signals comprise a neutral gear signal, an upshift signal and a downshift signal; compared with the prior art, the system has the beneficial effects that the power control device receives a gear instruction and transmits the gear instruction to the power output device, the power output device is mechanically connected with an engine gear shifting fork shaft through the power transmission device, gear shifting execution is achieved, and the system is integrally used for achieving clutch-free electric gear shifting and supports the one-key neutral gear function; and gear shifting is convenient.

Description

Technical Field

[0001] This invention relates to the field of racing technology, specifically an electric shifting system based on a DC brushed geared motor. Background Technology

[0002] Since its inception in 1981, the FSAE Formula Student competition has been held in more than 20 countries, including China, Germany, and the United States. The first Formula Student China competition was held at the Shanghai International Circuit in 2010, and as of 2022, more than 100 teams from China have participated in the competition.

[0003] According to the rules of the Formula Student China competition, the only requirement for the gear shifting device on a race car is that it be fixed to the chassis. However, due to the engine displacement limit of 710cc, almost all teams use motorcycle engines as their power source. Therefore, there are no mature and stable commercial gear shifting devices that can be directly adopted.

[0004] Currently, almost all Formula Student teams use pneumatic shifting systems, which use a cylinder filled with high-pressure gas to drive the engine shift fork. While this system is simple to install and has low barriers to entry, the gas cylinder needs frequent disassembly and refilling. The relatively uncontrollable gas thrust leads to poor shift success rate and low stability. When the motorcycle engine is in neutral between first and second gear, the pneumatic shifting system cannot accurately engage neutral, and its high weight does not align with the trend towards lightweighting in Formula Student racing. A small number of teams use purely mechanical shifting systems, which connect the engine shift fork to the shift lever in the cockpit via a cable. This method requires the rider to take one hand off the steering wheel and use considerable force to push the shift lever, making it difficult to time shifts accurately, resulting in relatively slow shifting speeds, and frequent shifting can easily lead to rider fatigue.

[0005] In conclusion, the shifting systems used by existing Formula Student teams all suffer from inconvenient shifting and need improvement. Summary of the Invention

[0006] The purpose of this invention is to provide an electric shifting system based on a DC brushed geared motor to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] An electric shifting system based on a DC brushed geared motor includes a power control device, a power output device, and a power transmission device.

[0009] The powertrain control unit, used to receive shift commands, generate motor control signals, and coordinate with the vehicle's ECU (electronic control unit, the central controller of the vehicle), includes:

[0010] The signal input module (including a neutral signal input device and a shift signal input device from the driver) is used to receive gear signals from the driver, including neutral signal, upshift signal, and downshift signal.

[0011] The delay control module (4 YYC-2S delay relays) is used to receive the gear position signal and output a control signal with a set timing based on the gear position signal.

[0012] The signal conversion module (a voltage divider circuit composed of adjustable resistors) is used to convert control signals with a set timing into corresponding motor control voltage signals.

[0013] The signal output module (specifically, the gear shift signal output device sent to the ECU) is used to send gear position signals to the ECU;

[0014] A power take-off device, used to drive gear shifting action according to a motor control voltage signal, includes:

[0015] The motor controller (specifically the APO-B3 motor controller) is used to receive motor control voltage signals and output motor drive current.

[0016] A geared motor (specifically a 775 motor and its matching gearbox) is used for the rotary motion required for gear shifting based on the output of the motor drive current.

[0017] The voltage conversion module (specifically a 12V to 24V inverter) is used to boost the vehicle power supply (12V) to the voltage required for the motor controller to operate (24V).

[0018] A power transmission device for transmitting rotary motion to the engine shift fork includes:

[0019] The motor end connector (specifically the first flange, made of aluminum) is used to fix the motor to the output shaft of the geared motor.

[0020] The engine end connector (specifically the second flange, made of aluminum) is used to fix the engine shift fork shaft;

[0021] Mechanical connectors (specifically bolts) are used to rigidly connect the motor end connectors and the engine end connectors;

[0022] The output of the signal input module is connected to the input of the delay control module and the input of the signal output module, respectively. The output of the delay control module is connected to the input of the signal conversion module. The output of the signal conversion module is connected to the input of the motor controller. The output of the motor controller is connected to the input of the geared motor. The output of the signal output module is connected to the ECU. The output of the voltage conversion module is connected to the power supply of the motor controller.

[0023] As a further embodiment of the present invention: the engine end connector is a second flange, which is fixedly connected to the engine shift fork shaft. Before fixing, the spline part of the shift fork shaft is cut off (specifically, it can be ground into a D-shaped shaft) to ensure space utilization and centering.

[0024] As a further aspect of the present invention: the voltage conversion module is a 12V to 24V inverter, and the output current of the 12V to 24V inverter is not less than 45A, so as to meet the working current requirements of the motor controller.

[0025] As a further aspect of the present invention: the reduction ratio of the geared motor is 400, its output torque is not less than 30 NM, and its no-load speed is not less than 95 r / min.

[0026] As a further aspect of the present invention: the delay control module includes four YYC-2S delay relays, and the YYC-2S delay relays adopt the P-35 working mode.

[0027] As a further aspect of the present invention: the signal conversion module is a voltage divider circuit composed of adjustable resistors, using adjustable resistors with a resistance value of not less than 5KΩ.

[0028] As a further embodiment of the present invention, the geared motor is fixed to the vehicle frame body by a rigid structure.

[0029] Compared with existing technologies, the advantages of this invention are as follows: The power control device of this invention receives gear position commands and transmits them to the power output device. The power output device is mechanically connected to the engine shift fork shaft through the power transmission device to realize gear shifting. The entire system is used to realize clutchless electric shifting and supports one-button neutral function, making shifting convenient. This invention eliminates the need for frequent disassembly and refilling of gas cylinders, and the range is no longer limited by the gas in the cylinder, making shifting more stable, convenient, and safe during competition. The reduction motor can continuously exert force during shifting, resulting in a higher success rate and stability. The output shaft of the reduction motor and the engine shift fork rotate coaxially, reducing damage to the engine during clutchless shifting. Upshifting and downshifting have independent time-delay relays, which work more perfectly with the ECU's upshifting cut-off and downshifting rev-matching functions, improving the success rate of shifting and protecting the engine. A separate neutral button is used to realize one-button neutral, avoiding the need to manually shift into neutral every time the car stops. The entire shifting system is significantly lighter and occupies less rear compartment space compared to pneumatic shifting, meeting the requirements for lightweighting and expanding space for other components in the rear compartment. Attached Figure Description

[0030] Figure 1 This is a circuit diagram of the power control device and the power output device.

[0031] Figure 2This is a schematic diagram of the power transmission device.

[0032] In the diagram: 1-gear motor, 2-first flange, 3-set screw, 4-engine shift fork, 5-second flange. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] Please see Figure 1 and Figure 2 An electric gear shifting system for Formula One racing cars based on a DC brushed geared motor 1, comprising a power control device, a power output device, and a power transmission device.

[0035] The powertrain control unit, used to receive shift commands, generate motor control signals, and coordinate with the vehicle's ECU (electronic control unit, the central controller of the vehicle), includes:

[0036] The signal input module (including a neutral signal input device and a shift signal input device from the driver) is used to receive gear signals from the driver, including neutral signal, upshift signal, and downshift signal.

[0037] The delay control module (4 YYC-2S delay relays) is used to receive the gear position signal and output a control signal with a set timing based on the gear position signal.

[0038] The signal conversion module (a voltage divider circuit composed of adjustable resistors) is used to convert control signals with a set timing into corresponding motor control voltage signals.

[0039] The signal output module (specifically, the gear shift signal output device sent to the ECU) is used to send gear position signals to the ECU;

[0040] A power take-off device, used to drive gear shifting action according to a motor control voltage signal, includes:

[0041] The motor controller (specifically the APO-B3 motor controller) is used to receive motor control voltage signals and output motor drive current.

[0042] Gear motor 1 (specifically a 775 motor and its matching gearbox) is used for the rotary motion required for gear shifting based on the output of the motor drive current.

[0043] The voltage conversion module (specifically a 12V to 24V inverter) is used to boost the vehicle power supply (12V) to the voltage required for the motor controller to operate (24V).

[0044] A power transmission device for transmitting rotary motion to the engine shift fork 4, comprising:

[0045] The motor end connector (specifically the first flange 2, made of aluminum) is used to fix the motor to the output shaft of the geared motor 1.

[0046] The engine end connector (specifically the second flange 5, made of aluminum) is used to fix the engine shift fork 4 shaft;

[0047] Mechanical connectors (specifically bolts) are used to rigidly connect the motor end connectors and the engine end connectors;

[0048] The output terminals of the signal input module are connected to the input terminals of the delay control module and the signal output module, respectively. The output terminal of the delay control module is connected to the input terminal of the signal conversion module. The output terminal of the signal conversion module is connected to the input terminal of the motor controller. The output terminal of the motor controller is connected to the input terminal of the geared motor 1. The output terminal of the signal output module is connected to the ECU. The output terminal of the voltage conversion module is connected to the power supply terminal of the motor controller.

[0049] The power transmission device connects the geared motor 1 to the engine; the power control device links the driver, engine and ECU to achieve human-vehicle integration.

[0050] The APO-B3 motor controller uses POT mode, i.e., analog voltage control mode. The motor controller has 5V, GND, and AIN inputs. Different voltages (0-5V) input to AIN correspond to different operating currents of the motor. The 12V to 24V inverter converts the race car's 12V battery to 24V to power the geared motor 1.

[0051] In this embodiment: Please refer to Figure 2 The engine end connector is the second flange 5, which is fixedly connected to the engine shift fork 4 shaft. Before fixing, the spline part of the shift fork shaft is cut off (specifically, it can be ground into a D-shaped shaft) to ensure space utilization and centering.

[0052] In this embodiment: Please refer to Figure 1 The voltage conversion module is a 12V to 24V inverter, and the output current of the 12V to 24V inverter is not less than 45A to meet the working current requirements of the motor controller.

[0053] In this embodiment: Please refer to Figure 1The reduction ratio of the geared motor 1 is 400, its output torque is not less than 30 NM, and its no-load speed is not less than 95 r / min.

[0054] In this embodiment: Please refer to Figure 1 The delay control module includes four YYC-2S delay relays, which operate in P-35 mode.

[0055] In P-35 mode, which means "send a signal, delay A time, the relay engages, and after B time, the relay disengages," the delay relays responsible for shifting gears and neutral need to have time A set to 0. The shifting gear swing time, delay ignition cut-off time, ignition cut-off time, neutral control voltage, and neutral swing time set in the delay control module can all be adjusted according to the actual working conditions.

[0056] The YYC-2S time delay relay has 12V and 0V power supply ports (DC+, DC-) and signal ports (IN+, IN-). The relay terminals have normally closed (NC), normally open (NO), and common (COM).

[0057] In this embodiment: Please refer to Figure 1 The signal conversion module is a voltage divider circuit composed of adjustable resistors, using adjustable resistors with a resistance of not less than 5KΩ.

[0058] It consists of several potentiometers (adjustable resistors). Through the coordination of the resistors, the voltage is divided to convert 5V into a usable voltage between 0-5V, which is then input to the motor controller to instruct the geared motor 1 to complete the upshift, downshift, and neutral actions.

[0059] In this embodiment: Please refer to Figure 2 The geared motor 1 is fixed to the vehicle frame body by a rigid structure.

[0060] In the power transmission device, the geared motor 1 is directly connected to the engine to ensure coaxiality and protect the engine shift fork 4. The flanges are bolted together for easy disassembly of the geared motor 1. The original splined shaft of the engine is replaced with a D-type shaft, which facilitates the machining of the flanges, improves concentricity, and reduces costs and saves space. The geared motor 1 and the signal transceiver are controlled by the opening and closing of a relay, without interference, to prevent the motor from being damaged by high voltage. The 12V platform of the signal transceiver facilitates cooperation with the vehicle power supply system and the engine control system (upshift cut-off and downshift rev-matching). The voltage divider input controller, through the cooperation of a potentiometer (variable resistor) and a fixed resistor, allows the motor to run at a lower speed. At the same time, the working time is controlled by a delay module to achieve precise control of the motor to shift the shift fork into neutral. The APO-B3 motor controller can achieve continuous flow during stall throttling, protecting the geared motor 1 and the engine from continuous power output. The inverter supplies 24V voltage to the geared motor 1 to ensure the torque of the geared motor 1 and improve the shift success rate.

[0061] Motor selection and reduction ratio determination: Based on the working conditions of racing cars and experience with traditional pneumatic shifting systems, the output speed of geared motor 1 under load is at least 40 r / min. The rotation angle of the Triumph 675 engine's upshifting and downshifting action is approximately 30°, so the time for the shift lever to swing to the desired position is approximately 0.125 s. The tension required to rotate the shift lever normally with a lever arm of 50 mm is 378.6 N, so the output shaft torque is at least 18.93 NM. To ensure shifting speed, 30 NM is selected as the target torque. Due to the advantages of brushed motors, especially the 775 motor, such as long life, high torque, and convenient control, after comparative calculations, a 24V 200W 775 motor is selected with a reduction gearbox with a reduction ratio of 400. At this time, the peak torque can reach 35 NM, and the peak output shaft speed (without load) can reach 95 r / min, which is sufficient to handle upshifting and downshifting conditions.

[0062] Connection method between geared motor 1 and engine shift fork 4: The original connection method of the engine is a super-dense spline connection, but the shift fork shaft is too long, so the spline part is cut off and ground into a D-shaped shaft. At the same time, an aluminum flange (first flange 2) that matches the size of the shaft is placed on the shaft, and a set screw 3 is screwed into the D-shaped surface for fixation. Similarly, the output shaft of geared motor 1 is also a D-shaped shaft. A flange (second flange 5) is installed in the same way, and the two flanges are then connected with bolts.

[0063] Motor controller selection: In the operation of an electric shift system, forward and reverse rotation control, speed control, and stall current limiting without interruption of current are paramount. Simultaneously, to ensure instantaneous torque output, the controller must have the ability to instantly deliver large currents. Therefore, the APO-B3 motor controller is selected, with a peak current capacity of up to 20A. It adopts POT mode and has 5V, GND, and AIN inputs. Different voltages (0-5V) are applied to AIN, corresponding to different operating currents and speeds (or torques) of the motor.

[0064] Upshift ignition cutoff control logic: For motorcycle engines, the shift lever has a period of free travel before rotating to the angle where shifting can be achieved. To minimize the power interruption time during upshifting, this free travel ignition cutoff must be eliminated. Therefore, after receiving the upshift signal, the shift system first executes the upshift action, and then cuts off the engine ignition after a certain period of time. This delay ignition cutoff time and the actual cutoff time need to be tested through specific experiments. We use the P-35 mode of a delay relay: "Send a signal, delay A time, the relay engages, engages B time, and then the relay disengages" to precisely control these two times.

[0065] Upshifting, downshifting, and neutral control circuit: For motorcycle engines, the longer the motor's power delivery time during upshifting and downshifting, the higher the shift success rate. However, excessively long delivery times can cause the gear lever to be under continuous stress, potentially leading to torsional deformation and other problems. Therefore, it's crucial to minimize the power delivery time while ensuring a high shift success rate. To precisely control this timing, we employ the P-35 mode, using three delay relays to control upshifting, downshifting, and neutral shifting respectively. However, in this case, time A needs to be adjusted to zero.

[0066] The APO-B3 motor controller uses POT mode. Different voltages between 0-5V input to the AIN port correspond to different motor operating currents. An input of 2.45-2.55V keeps the motor stationary. To ensure shifting speed, 5V and 0V voltages (corresponding to two different rotation directions) are supplied to the AIN port to complete the shifting action. Since neutral is between first and second gear and the angle is small, simply operating the motor at maximum current while controlling the time would only result in approximately 20ms, making precise control difficult. Therefore, when shifting into neutral, the motor should operate at a low current, slowing the rotation speed and lengthening the operating time, allowing for more precise angle control. For Formula Student racing and the race car itself, starting in second gear is almost never used in first gear. Therefore, only the case of shifting from second gear to neutral is considered, i.e., inputting a suitable voltage between 0-2.45V to the AIN port while using a delay module to control the time. The determination of this voltage and time will be clarified in subsequent specific tests.

[0067] At this point, the input voltage to the AIN port is 2.5V (static voltage between 2.45-2.55V), 0V, 5V, and a 0-2.45V neutral voltage. The APO-B3 motor controller has 5V and 0V output voltages. Using this power supply and three adjustable resistors, a voltage divider circuit is used to obtain the required voltage. To ensure the safety of the control board, the current in the voltage divider circuit cannot be too large. We selected a 10K resistance value for the adjustable resistors (any value greater than 10K is acceptable). The specific logic is as follows:

[0068] Adjustable resistors can be categorized by function into fixed resistors, shift resistors, and neutral resistors. The fixed resistor and shift resistor work together as a voltage divider (with their resistance values ​​adjusted to be equal) to provide the controller with the quiescent voltage and the shift voltage. These two resistors are connected through the common and normally closed terminals of the neutral delay module. Simultaneously, the common and normally closed terminals of the shift delay module are connected in series, instantly disconnecting the quiescent voltage and connecting the shift voltage during shift actions. Although the shift resistor and fixed resistor have the same resistance value, fixed-value resistors cannot be used because even fixed-value resistors of the same model can have slight differences in resistance, which may cause the quiescent voltage to deviate from 2.45-2.55V. The neutral resistor works together as a voltage divider with the fixed resistor. During neutral action, the neutral delay module disconnects the connection between the fixed resistor and the shift resistor, connecting the fixed resistor and the neutral resistor, instantly changing the quiescent voltage to the neutral voltage. The specific schematic diagram is shown below. Figure 1 As shown.

[0069] The testing of shifting time, delay ignition cut-off time, and ignition cut-off time: This section has been mentioned above. Firstly, regarding the shifting success rate, the longer the shift fork swing time and the shorter the delay ignition cut-off time, the higher the shifting success rate. However, if the shift lever continues to exert force for a long time after a successful shift, the shift fork may twist and deform, and the motor will be in a stalled state, which is extremely dangerous. Therefore, the swing time should be as short as possible while ensuring the success rate. As for the delay ignition cut-off time, there is a period of idle travel before the shift lever rotates to the angle where the shift can be achieved. In order to minimize the power interruption time during upshifting, this idle travel ignition cut-off should be eliminated. However, if the time is too short, it will still cause the power interruption time to be too long. If this time is too long, the shifting success rate will be greatly reduced. As for the ignition cut-off time, too short will greatly reduce the shifting success rate, and too long will cause the power interruption time to be too long. These times must be obtained through specific experiments, the specific experimental method is as follows: The test condition for upshifting is full throttle at 8000 RPM from second to third gear, and the time is adjusted in 10ms increments. Since the driver cannot guarantee that the upshift will be exactly 8000 RPM every time, each set of data is tested 30 times. First, the ignition cut-off time test is conducted (the upshift / downshift swing time is as long as possible, but not too long, so we take 500ms, and the delayed ignition cut-off time is 0) to obtain the optimal ignition cut-off time 'a'. Then, the delayed ignition cut-off time test is conducted using this optimal ignition cut-off time to obtain the optimal delayed ignition cut-off time 'b'. The true optimal ignition cut-off time is then c=ab. Based on the obtained times b and c, the upshift / downshift swing time test is conducted (the downshift test condition is 40km / h from third to second gear (this is the most commonly used condition)). The specific experimental data is as follows (only meaningful data is shown in the table):

[0070] Flameout time test (oscillation time 500ms, delayed flameout time 0, success rate calculated after removing unreliable data), Table 1, Flameout time test table:

[0071]

[0072] As shown in Table 1, when the ignition cut-off time is greater than 160ms, the shift success rate has basically stabilized at around 95%, which meets the usage requirements. In order to ensure fast shifting, time a is taken as 160ms at this time.

[0073] Delayed flameout time test (oscillation time 500ms, flameout time 150ms, success rate calculated after removing unreliable data), Table 2, Delayed Flameout Time Test Table:

[0074]

[0075] As shown in Table 2, when the delay ignition time exceeds 70ms, the success rate begins to drop significantly. To ensure the shortest power interruption time, the delay ignition time b is set to 70ms. Therefore, the optimal ignition time is 160-70=90ms. When these two data are written into the vehicle for testing, the success rate remains stable at around 95%, indicating that the test results are reliable.

[0076] Upshift / downshift swing time test (ignition cut-off time 90ms, delayed ignition cut-off time 70ms, success rate calculated after removing unreliable data), Table 3, Upshift / downshift swing time test table:

[0077]

[0078] As shown in Table 3, when the upshift swing time is 330ms and the downshift swing time is more than 400ms, the shift success rate can be stabilized at around 95%. Therefore, the swing time is set to 330ms and 400ms respectively.

[0079] Neutral control voltage and swing time adjustment: In order to facilitate precise control of the swing angle, the neutral output current is required to be much smaller than the up and down gear current. However, if the current is too small, the motor torque will be insufficient and the shift fork will not be able to turn. Actual test was conducted on the vehicle.

[0080] Through actual measurement, the critical control voltage that can make the shift fork rotate stably is about 1.85V, which is rounded to 1.8V here; then the working time of the neutral delay relay is gradually adjusted. When the engine can be shifted from second gear to neutral, the time is 210ms, that is, the neutral swing time is 210ms.

[0081] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and not restrictive.

[0082] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An electric gear shifting system based on a DC brushed geared motor, characterized in that, The electric shifting system based on a DC brushed geared motor includes a power control device, a power output device, and a power transmission device. The power control unit, used to receive shift commands, generate motor control signals, and coordinate with the vehicle ECU, includes: The signal input module is used to receive gear signals from the driver, including neutral, upshift, and downshift signals. The delay control module is used to receive the gear position signal and output a control signal with a set timing based on the gear position signal; The signal conversion module is used to convert control signals with a set timing sequence into corresponding motor control voltage signals; The signal output module is used to send gear position signals to the ECU; A power take-off device, used to drive gear shifting action according to a motor control voltage signal, includes: The motor controller is used to receive motor control voltage signals and output motor drive current; A geared motor is used for the rotary motion required for gear shifting based on the output of the motor drive current. The voltage conversion module is used to boost the vehicle's power supply to the voltage required for the motor controller's operation. A power transmission device for transmitting rotary motion to the engine shift fork includes: Motor end connector, used to fix to the output shaft of the geared motor; Engine end connector, used to fix to the engine shift fork shaft; Mechanical connectors are used to rigidly connect the motor end connectors and the engine end connectors. The output terminals of the signal input module are connected to the input terminals of the delay control module and the signal output module, respectively. The output terminal of the delay control module is connected to the input terminal of the signal conversion module. The output terminal of the signal conversion module is connected to the input terminal of the motor controller. The output terminal of the motor controller is connected to the input terminal of the geared motor. The output terminal of the signal output module is connected to the ECU. The output terminal of the voltage conversion module is connected to the power supply terminal of the motor controller.

2. The electric shifting system based on a DC brushed geared motor according to claim 1, characterized in that, The engine end connector is a second flange, which is fixedly connected to the engine shift fork shaft. Before fixing, the spline part of the shift fork shaft is cut off to ensure space utilization and centering.

3. The electric shifting system based on a DC brushed geared motor according to claim 1, characterized in that, The voltage conversion module is a 12V to 24V inverter, and the output current of the 12V to 24V inverter is not less than 45A to meet the working current requirements of the motor controller.

4. The electric shifting system based on a DC brushed geared motor according to claim 1, characterized in that, The reduction ratio of the geared motor is 400, its output torque is not less than 30 NM, and its no-load speed is not less than 95 r / min.

5. The electric shifting system based on a DC brushed geared motor according to claim 1, characterized in that, The delay control module includes four YYC-2S delay relays, which operate in P-35 mode.

6. The electric shifting system based on a DC brushed geared motor according to claim 1, characterized in that, The signal conversion module is a voltage divider circuit composed of adjustable resistors, using adjustable resistors with a resistance of not less than 5KΩ.

7. The electric shifting system based on a DC brushed geared motor according to claim 4, characterized in that, The geared motor is fixed to the vehicle frame body by a rigid structure.

Images