A center motor for measuring pedal force and vehicle

Abstract

The application discloses a kind of measure pedal force middle motor and vehicle, measure pedal force middle motor includes first shell, second shell and third shell, the outside of first shell has force chain wheel, tooth disc and power chain wheel;Swing arm shaft is through first shell, swing arm shaft is connected with inside swing arm, outside swing arm in first shell inside, outside;Outside swing arm, swing arm shaft and inside swing arm form the lever mechanism with swing arm shaft as fulcrum, convert the rotation angle of swing arm shaft into external force that force chain wheel is received;Power chain wheel is on power chain wheel shaft, there is speed reduction gear between first shell and second shell, speed reduction gear is on power chain wheel shaft;There is motor between second shell and third shell, motor shaft of motor is engaged with speed reduction gear, torque of motor is sequentially transmitted to power chain wheel shaft and power chain wheel through motor shaft, speed reduction gear, one-way bearing.The application can capture pedal force in real time by lever mechanical conversion mechanism, timely and accurately control motor to provide power.

Description

Technical Field

[0001] This utility model relates to a centrally located motor and vehicle for measuring pedal force, belonging to the field of vehicle power assist technology. Background Technology

[0002] In recent years, electric-assist bicycles have rapidly gained popularity in the global market due to their environmental friendliness and convenience. As the core drive unit, the accuracy of the mid-drive motor's pedal force detection directly determines the smoothness of the assist system's response and its energy efficiency.

[0003] Existing technologies mostly use strain gauges or torque sensors to detect bottom bracket torque. These methods are susceptible to temperature drift and mechanical vibration, and are prone to zero-point drift after long-term use, leading to inaccurate power assist, delayed response, or overshoot. Especially under low cadence conditions, the signal-to-noise ratio is significantly reduced, affecting the riding experience.

[0004] Measurement errors can trigger a chain of malfunctions in the control system. For example, with over-compensation during light pedaling, a user's actual pedaling force of 10 Nm torque might be misinterpreted as 15 Nm, causing the motor to output excessive current, resulting in gear impact and wear. Furthermore, some regions prohibit the ratio of motor assist to pedaling force from exceeding a certain value. Conversely, with under-compensation during heavy pedaling, a user's actual pedaling force of 80 Nm might only be detected as 60 Nm. Insufficient motor assist forces the rider to exert excessive force, causing abnormal impact loads on the bottom bracket bearing.

[0005] Some existing technologies use the method of bottom bracket speed compensation to estimate pedaling force, but speed compensation cannot capture static pedaling force, resulting in power assist delay; or when the vehicle is going downhill, the motor still outputs inappropriate power assist. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a mid-mounted motor and vehicle for measuring pedal force. This motor can capture pedal force in real time through a lever-type force conversion mechanism, and control the motor to provide assistance in a timely and precise manner. This invention achieves the above objective using the following technical solution:

[0007] In a first aspect, this utility model provides a mid-mounted motor for measuring pedal force, comprising a first housing, a second housing, and a third housing, wherein the first housing is connected to one side of the second housing, and the third housing is connected to the other side of the second housing;

[0008] The outer side of the first housing is provided with a force-measuring sprocket, a toothed sprocket, and an assist sprocket;

[0009] The swing arm shaft passes through the first housing via a bearing, and the swing arm shaft is connected to an inner swing arm and an outer swing arm on the inner and outer sides of the first housing, respectively.

[0010] The force-measuring sprocket is connected to the outer swing arm via a bearing. A force-measuring spring is provided on the inner side of the first housing. One end of the force-measuring spring is connected to the boss on the inner side of the first housing, and the other end is connected to the inner swing arm.

[0011] The outer swing arm, the swing arm shaft, and the inner swing arm form a lever mechanism with the swing arm shaft as the fulcrum; the lever mechanism is used to convert the external force on the force measuring sprocket into the rotation angle of the swing arm shaft under the reaction force of the force measuring spring.

[0012] The crankshaft is mounted on the central shaft that runs through the first housing and the second housing via a one-way clutch. When the rotation direction of the central shaft is the direction that causes the vehicle to move forward, the one-way clutch is locked, and the rotational torque on the central shaft is transmitted to the crankshaft.

[0013] The power assist sprocket is mounted on the power assist sprocket shaft that passes through the first housing. A reduction gear is provided in the cavity between the first housing and the second housing. The reduction gear is mounted on the power assist sprocket shaft via a one-way bearing. A power assist motor is provided in the cavity between the second housing and the third housing. The motor shaft of the power assist motor meshes with the reduction gear. When the power assist motor is driving the vehicle forward, the one-way bearing is locked, and the torque of the power assist motor is transmitted sequentially through the motor shaft, the reduction gear, and the one-way bearing to the power assist sprocket shaft and the power assist sprocket.

[0014] In conjunction with the first aspect, optionally, the end of the swing arm shaft is connected to a permanent magnet spacer via a spacer bolt, and one end face of the permanent magnet spacer abuts against the inner swing arm to mechanically limit the axial displacement of the inner swing arm.

[0015] The other end face of the permanent magnet spacer is provided with a radially magnetized encoder magnet;

[0016] A first circuit board is provided in the cavity between the first housing and the second housing, and a swing arm shaft magnetic encoder is provided on the first circuit board;

[0017] The sensing center of the swing arm shaft magnetic encoder is axially aligned with the geometric center of the encoder magnet. The swing arm shaft magnetic encoder obtains the rotation angle of the swing arm shaft by sensing the rotation angle of the encoder magnet. The rotation angle of the swing arm shaft is calculated and processed by the controller of the first circuit board to obtain the magnitude of the output current of the assist motor.

[0018] In conjunction with the first aspect, optionally, a central axis magnetic ring is provided on the central axis; a first circuit board is provided in the cavity between the first housing and the second housing, and a central axis Hall effect sensor is provided on the first circuit board;

[0019] The central axis Hall effect sensors are distributed around the central axis magnetic ring;

[0020] When the central axis rotates, it drives the central axis magnetic ring to rotate. The magnetic field of the central axis magnetic ring sweeps across the central axis Hall, triggering a change in the electrical signal output by the central axis Hall. The electrical signal output by the central axis Hall is used to obtain the rotation speed of the central axis.

[0021] In conjunction with the first aspect, optionally, there are two central axis Hall sensors, including a first central axis Hall sensor and a second central axis Hall sensor;

[0022] The first and second central axis Hall effect sensors are arranged in a ring around the central axis magnetic ring, and the relative magnetic field angle between the first and second central axis Hall effect sensors is 90 degrees.

[0023] When the central axis rotates, it drives the central axis magnetic ring to rotate. The magnetic field of the central axis magnetic ring sweeps through the first central axis Hall and the second central axis Hall in sequence. The rotation speed and direction of the central axis are obtained based on the time and sequence of the rising and / or falling edges of the electrical signals output by the first and second central axis Halls.

[0024] In conjunction with the first aspect, optionally, a chip-attracting permanent magnet is provided at the bottom of the cavity between the first housing and the second housing. The chip-attracting permanent magnet is located at the bottom of the outer end face of the reduction gear and is used to attract iron filings generated by the reduction gear during meshing transmission, so as to reduce the wear of the reduction gear.

[0025] In conjunction with the first aspect, optionally, the power assist motor includes a stator fixed in the inner cavity of the third housing, a rotor coaxially disposed with the stator, and a motor shaft rigidly connected to the rotor;

[0026] The motor shaft is provided with a helical gear at one end facing the second housing, and the helical gear meshes with a reduction gear to drive the power sprocket shaft;

[0027] The direction of rotation of the helical gear satisfies the following: when the motor shaft drives the reduction gear, the axial force generated by the meshing inhibits the relative displacement between the reduction gear and the motor shaft in the axial direction.

[0028] In conjunction with the first aspect, optionally, a Hall plate is provided in the cavity between the third housing and the second housing. The Hall plate is disposed on the second housing, and the sensing center point of the Hall chip on the Hall plate is aligned with the center axis of the permanent magnet end face on the rotor for measuring the angle of the magnetic poles on the rotor.

[0029] In conjunction with the first aspect, optionally, the end face of the motor shaft facing the first housing is provided with a radially magnetized motor shaft magnet;

[0030] A second circuit board is provided in the cavity between the first housing and the second housing, and a motor rotor magnetic encoder is provided on the second circuit board;

[0031] The sensing center of the motor rotor magnetic encoder is aligned with the center of the motor shaft magnet. The motor rotor magnetic encoder obtains the angle of the magnetic poles on the motor rotor by sensing the rotation angle of the motor shaft magnet.

[0032] In conjunction with the first aspect, optionally, an auxiliary sprocket is provided on the outer side of the first housing. The auxiliary sprocket is connected to an auxiliary sprocket shaft via a bearing, and the auxiliary sprocket shaft is fixedly connected to the first housing. The auxiliary sprocket is used to increase the wrap angle of the chain with respect to the assist sprocket.

[0033] Secondly, this utility model provides a vehicle, including the centrally located motor and chain for measuring pedal force as described in the first aspect. The chain starts from the flywheel of the drive wheel, passes in sequence around the auxiliary sprocket, the assist sprocket, the force measuring sprocket and the chainring, and returns to the flywheel of the drive wheel to form a closed loop.

[0034] Compared with the prior art, the beneficial effects achieved by the mid-drive motor and vehicle for measuring pedal force provided by this utility model embodiment include:

[0035] This invention relates to a swing arm shaft that passes through a first housing via bearings. An inner swing arm and an outer swing arm are connected to the swing arm shaft on the inner and outer sides of the first housing, respectively. A force-measuring sprocket is connected to the outer swing arm via bearings. A force-measuring spring is provided on the inner side of the first housing, with one end connected to a boss on the inner side of the first housing and the other end connected to the inner swing arm. The outer swing arm, swing arm shaft, and inner swing arm form a lever mechanism with the swing arm shaft as the fulcrum. The lever mechanism is used to convert the external force on the force-measuring sprocket into the rotation angle of the swing arm shaft under the reaction force of the force-measuring spring. This invention utilizes the linear reaction force of the force-measuring spring to convert the external force into the rotation angle of the swing arm shaft. Using the lever mechanism of the outer swing arm, swing arm shaft, and inner swing arm, the pedal force on the force-measuring sprocket is accurately and in real-time converted into an easily detectable physical quantity, improving the accuracy of pedal force measurement and solving the problem of distortion in low-frequency pedal force measurement.

[0036] This invention relates to a crankset with a one-way clutch mounted on a central shaft that runs through the first and second housings. When the central shaft rotates in the direction that propels the vehicle forward, the one-way clutch locks, transmitting the rotational torque from the central shaft to the crankset. The one-way clutch provides both a forward locking mechanism and a reverse disengagement mechanism. When the rider pedals forward, the torque is transmitted to the crankset to drive the vehicle. When pedaling stops or the pedals are reversed, the crankset is mechanically decoupled from the central shaft. This invention reduces idle speed loss and enables pure electric riding without the need for pedals.

[0037] This invention can achieve real-time and accurate matching between the output torque of the power assist motor and the pedaling force of the rider through a high-precision lever-type mechanical conversion mechanism and non-contact magnetic coding detection. It solves the problem of insufficient or excessive power assist motor output caused by measurement errors in traditional systems, significantly improves riding comfort, reduces system energy consumption, extends component life, and complies with the electric power assist regulations of various regions. Attached Figure Description

[0038] Figure 1 A schematic diagram of a mid-mounted motor for measuring foot pedal force is provided in Embodiment 1 of this utility model;

[0039] Figure 2 A schematic diagram of the outer side of the first housing of a mid-mounted motor for measuring foot pedal force, provided in Embodiment 1 of this utility model;

[0040] Figure 3 A schematic diagram of the inner side of the first housing of a mid-mounted motor for measuring foot pedal force, provided in Embodiment 1 of this utility model;

[0041] Figure 4 An axial cross-sectional view of the swing arm shaft of a mid-mounted motor for measuring pedal force, provided in Embodiment 1 of this utility model;

[0042] Figure 5 An axial cross-sectional view of the central shaft of a mid-mounted motor for measuring pedal force, provided in Embodiment 1 of this utility model;

[0043] Figure 6 This is a schematic diagram of the inner side of the second housing of a mid-mounted motor for measuring foot pedal force, provided in Embodiment 1 of this utility model.

[0044] Figure 7 A schematic diagram of the outer side of the second housing of a mid-mounted motor for measuring foot pedal force, provided in Embodiment 1 of this utility model;

[0045] Figure 8 An axial sectional view of the drive shaft of a mid-drive motor for measuring pedal force, provided in Embodiment 1 of this utility model;

[0046] Figure 9 An axial cross-sectional view of a motor rotor magnetic encoder for measuring foot pedal force provided in Embodiment 1 of this utility model;

[0047] Figure 10 An axial cross-sectional view of the auxiliary sprocket of a mid-mounted motor for measuring pedal force, provided in Embodiment 1 of this utility model;

[0048] Figure 11 A schematic diagram of the assist principle of a mid-mounted motor for measuring pedal force, provided in Embodiment 1 of this utility model;

[0049] Figure 12 This is a structural schematic diagram of a vehicle provided in Embodiment 2 of the present invention.

[0050] In the picture:

[0051] 101. First housing; 1011. Boss; 1012. Swing arm limiter; 102. Second housing; 1021. Central shaft hole reinforcing rib; 1022. Sealing groove; 103. Third housing; 104. Assembly hole; 105. Pin hole; 1051. Pin; 106. Hanger hole; 107. Wave-shaped elastic washer; 108. Oil seal; 109. Oil reservoir;

[0052] 201. Force measuring sprocket; 2011. Force measuring sprocket shaft; 202. Outer swing arm; 203. Inner swing arm; 204. Swing arm shaft; 2041. Permanent magnet spacer; 2042. Spacer bolt; 205. Force measuring spring;

[0053] 301. Crankset; 302. Bottom shaft; 303. One-way clutch;

[0054] 401. Power sprocket; 402. Power sprocket shaft; 403. Reduction gear; 4031. Chip-collecting permanent magnet; 404. One-way bearing;

[0055] 501, stator; 502, rotor; 503, motor shaft; 5031, helical gear;

[0056] 601. Encoder magnet; 602. Swing arm shaft magnetic encoder; 603. Central shaft magnetic ring; 604. Central shaft Hall effect sensor; 605. Hall effect board; 6051. Hall effect chip; 606. Motor shaft magnet; 607. Motor rotor magnetic encoder;

[0057] 701, Auxiliary sprocket; 7012, Auxiliary sprocket shaft;

[0058] 801. Chain; 802. Drive wheel; 8021. Flywheel; 803. Crank; 804. Pedal; 805. Cable;

[0059] 9. The central motor for measuring foot pedal force. Detailed Implementation

[0060] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0061] In the description of this utility model, it should be noted that the terms "upper / lower end," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0062] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "set / sleeved," "sleeve," "connection," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0063] Example 1:

[0064] In this embodiment, the following is provided: Figure 1 The illustrated mid-drive motor for measuring pedal force includes a first housing 101, a second housing 102, and a third housing 103. The first housing 101 is connected to one side of the second housing 102, and the third housing 103 is connected to the other side of the second housing 102.

[0065] like Figure 1 and Figure 2 As shown, the outer side of the first housing 101 is provided with a force-measuring sprocket 201, a toothed sprocket 301, a booster sprocket 401, and an auxiliary sprocket 701. Figure 1 and Figure 6 As shown, a first circuit board and a reduction gear 403 are disposed in the cavity between the first housing 101 and the second housing 102. Figure 1 and Figure 8 As shown, an assist motor is provided in the cavity between the third housing 103 and the second housing 102.

[0066] In this embodiment, for ease of description, the side where the second housing 102 is connected to the first housing 101 is referred to as the inner side of the second housing 102, and the side where the second housing 102 is connected to the third housing 103 is referred to as the outer side of the second housing 102.

[0067] like Figure 1As shown, the first housing 101 and the second housing 102 are symmetrically provided with a plurality of assembly holes 104 and a plurality of pin holes 105 on their periphery. The assembly holes 104 are used to connect the first housing 101 and the second housing 102 together with bolts. The pin holes 105 are used to connect the first housing 101 and the second housing 102 together radially with pins 1051. The pins 1051, while connecting the first housing 101 and the second housing 102, can prevent the bolts from being damaged by large shear forces. The outer center of the second housing 102 and the periphery of the third housing 103 are provided with a plurality of assembly holes 104 and a plurality of pin holes 105. The assembly holes 104 are used to connect the second housing 102 and the third housing 103 together with bolts. The pin holes 105 are used to connect the second housing 102 and the third housing 103 together radially with pins 1051. The pins 1051, while connecting the second housing 102 and the third housing 103, can prevent the bolts from being damaged by large shear forces.

[0068] In this embodiment, there are at least three assembly holes 104 and at least two pin holes 105 for connecting the first housing 101 and the second housing 102. There are at least three assembly holes 104 and at least two pin holes 105 for connecting the second housing 102 and the third housing 103.

[0069] A sealing groove 1022 is provided on the contact surface of the first housing 101 and the second housing 102. The sealing groove 1022 is used to install a sealing rubber ring or to accommodate sealant. Figure 8 As shown, in this embodiment, the sealing groove 1022 is disposed on the second housing 102.

[0070] like Figure 1 and Figure 2 As shown, the outer side of the first housing 101 is provided with a force measuring sprocket 201, a toothed sprocket 301, a booster sprocket 401, and an auxiliary sprocket 701.

[0071] Preferably, the auxiliary sprocket 701, the power sprocket 401, the force measuring sprocket 201, and the sprocket 301 are in the same plane in the axial direction, and the axial error does not exceed 2 mm.

[0072] In this embodiment, the outer surfaces of the first housing 101 and the second housing 102 are provided with outer reinforcing ribs, and the inner surfaces are provided with inner reinforcing ribs, which are used to improve the overall rigidity and deformation resistance of the housing, while optimizing heat dissipation performance. The outer side of the first housing 101 is provided with vent holes to balance the pressure difference between the inside and outside and prevent moisture accumulation, while meeting the IP54 protection level requirements.

[0073] like Figure 4 As shown, the swing arm shaft 204 passes through the first housing 101 via a bearing.

[0074] In this embodiment, a retaining ring is provided between the bearing and the first housing 101 to achieve axial fixation of the bearing, the rocker arm shaft 204 and the first housing 101.

[0075] like Figure 2 As shown, the swing arm shaft 204 is connected to an outer swing arm 202 on the outside of the first housing 101. In this embodiment, to reduce assembly costs, such as Figure 4 The outer swing arm 202 and the swing arm shaft 204 shown are integrated into one design.

[0076] like Figure 4 As shown, the force measuring sprocket 201 is connected to the outer swing arm 202 through a bearing.

[0077] Specifically, the force measuring sprocket 201 has a force measuring sprocket shaft 2011 in the middle, the force measuring sprocket shaft 2011 is fixed on the outer swing arm 202, and a bearing is provided on the force measuring sprocket shaft 2011 to realize the connection between the force measuring sprocket 201 and the force measuring sprocket shaft 2011.

[0078] In this embodiment, the force measuring sprocket shaft 2011 is axially fixed to the outer swing arm 202 by a snap ring.

[0079] like Figure 3 As shown, the swing arm shaft 204 is connected to the inner swing arm 203 inside the first housing 101. A force-measuring spring 205 is provided inside the first housing 101. One end of the force-measuring spring 205 is connected to the boss 1011 inside the first housing 101, and the other end is connected to the inner swing arm 203.

[0080] Multiple hanging points are provided on the inner swing arm 203 to adjust the initial length and initial tension of the force measuring spring 205.

[0081] like Figure 3 As shown, a protruding swing arm limiter 1012 is provided on the inner side of the first housing 101. When the force measuring sprocket 201 is not subjected to external force, the inner swing arm 203, under the action of the force measuring spring 205, contacts the swing arm limiter 1012 on its side to limit the initial angle of the swing arm shaft 204.

[0082] like Figure 4 As shown, the outer swing arm 202, the swing arm shaft 204, and the inner swing arm 203 form a lever mechanism with the swing arm shaft 204 as the fulcrum. The lever mechanism is used to convert the external force on the force-measuring sprocket 201 into the rotation angle of the swing arm shaft 204 under the reaction force of the force-measuring spring 205.

[0083] like Figure 11 As shown, in the initial state, the chain segment 801 located between the assist sprocket 401 and the chainring 301 is subjected to pressure from the force-measuring sprocket 201. Figure 11(From the center to the lower right) forming a bent state, the contact points of chain 801 with the assist sprocket 401, chain 801 with the force measuring sprocket 201, and chain 801 with the chain chain 301 are distributed in a triangular pattern (e.g., Figure 11 (As shown by the dashed line). When the chainring 301 rotates forward and the drive wheel 802 experiences driving resistance, the originally triangularly distributed chain segment 801 tends to tighten, forming a resultant force on both sides of the connection point between the force-measuring sprocket 201 and the chain 801 (as shown by the dashed line). Figure 11 (in the upper left direction), this resultant force causes the outer swing arm 202 connected to the force measuring sprocket 201 to tend to rotate around the swing arm axis 204 (e.g.) Figure 11 (The middle direction is clockwise).

[0084] Compared to directly measuring the pedal force or the external force on the force-measuring sprocket 201, measuring the rotation angle of the swing arm shaft 204 is easier and more accurate. Furthermore, once the chain 801 is taut, no matter how much force is applied to the pedal 804, the rotation angle of the swing arm shaft 204 will no longer change, effectively preventing the entire force-measuring system from being damaged by a huge external impact.

[0085] like Figure 4 As shown, the end of the swing arm shaft 204 is connected to a permanent magnet spacer 2041 via a spacer bolt 2042. One end face of the permanent magnet spacer 2041 abuts against the inner swing arm 203 and is used to mechanically limit the axial displacement of the inner swing arm 203; the other end face of the permanent magnet spacer 2041 is provided with a radially magnetized encoder magnet 601.

[0086] In this embodiment, the permanent magnet spacer 2041 is made of a non-magnetic material, such as aluminum alloy, which helps to reduce the interference of the magnetic field on the encoder magnet 601.

[0087] The first circuit board is equipped with a swing arm shaft magnetic encoder 602, the sensing center of which is axially aligned with the geometric center of the encoder magnet 601. The swing arm shaft magnetic encoder 602 obtains the rotation angle of the swing arm shaft 204 by sensing the rotation angle of the encoder magnet 601. The rotation angle of the swing arm shaft 204 is then calculated and processed by the controller on the first circuit board to obtain the magnitude of the motor output current.

[0088] In this embodiment, the axial distance between the encoder magnet 601 and the swing arm shaft magnetic encoder 602 is no greater than 5 mm.

[0089] This embodiment utilizes the linear reaction force of the force-measuring spring 205 to convert the external force into the rotation angle of the swing arm shaft 204. The lever mechanism of the outer swing arm 202, swing arm shaft 204, and inner swing arm 203 amplifies the minute pedal force displacement experienced by the force-measuring sprocket 201 to a range easily detectable. Furthermore, the swing arm shaft magnetic encoder 602 senses the rotation angle of the encoder magnet 601 to obtain the rotation angle of the swing arm shaft 204, thereby improving the accuracy of pedal force measurement and solving the problem of distortion in low-frequency pedal force measurement.

[0090] like Figure 1 and Figure 5 As shown, the chainring 301 is mounted on the central shaft 302 that passes through the first housing 101 and the second housing 102 via a one-way clutch 303. When the rotation direction of the central shaft 302 is the rotation direction that causes the vehicle to move forward, the one-way clutch 303 is locked, and the rotational torque on the central shaft 302 is transmitted to the chainring 301.

[0091] Specifically, the two ends of the central shaft 302 are connected to the first housing 101 and the second housing 102 via bearings. An oil seal 108 is also provided between the bearing and the housing to prevent liquid and dust from entering the cavity between the first housing 101 and the second housing 102. A wave-shaped elastic washer 107 is provided on the outer ring of the bearing between the central shaft 302 and the second housing 102.

[0092] Furthermore, an oil reservoir 109 is provided between the bearing and the oil seal 108 to store lubricating oil and thus continuously provide lubrication to the bearing and the oil seal 108.

[0093] like Figure 7 As shown, the second housing 102 has an outwardly protruding cylindrical groove, and the central shaft 302 is connected to the inner side of the cylindrical groove. The outer side of the cylindrical groove is provided with a central shaft hole reinforcing rib 1021 to enhance the overall rigidity and deformation resistance of the cylindrical groove.

[0094] like Figure 5 As shown, a central magnetic ring 603 is disposed on the central shaft 302, and a central Hall effect sensor 604 is disposed on the first circuit board. The central Hall effect sensors 604 are distributed around the central magnetic ring 603. When the central shaft 302 rotates, it drives the central magnetic ring 603 to rotate. The magnetic field of the central magnetic ring 603 sweeps across the central Hall effect sensors 604, triggering a change in the electrical signal output by the central Hall effect sensors 604. The electrical signal output by the central Hall effect sensors 604 is used to obtain the rotational speed of the central shaft 302.

[0095] As a further improvement, the rotational speed of the central shaft 302 and the rotational angle of the swing arm shaft 204 are calculated and processed by the controller on the first circuit board to obtain the magnitude of the motor output current.

[0096] In this embodiment, the central magnetic ring 603 is axially fixed to the central shaft 302 by a snap ring.

[0097] In this embodiment, the one-way clutch 303 adopts a one-way ratchet. For details of the one-way ratchet mechanism, please refer to the application number 2024226502770 filed by the applicant on October 31, 2024, regarding a crankcase one-way ratchet structure and a transport tool.

[0098] Specifically, when the rotation direction of the central shaft 302 is the same as the preset rotation direction of the one-way clutch 303, the central shaft 302 drives the transmission chain to rotate through the one-way crank assembly, and the central shaft 302 outputs driving force; when the rotation direction of the central shaft 302 is different from the preset rotation direction of the one-way clutch 303, the central shaft 302 idles; when the one-way clutch 303 is in use, the rotation direction of the central shaft 302 is the same as the rotation direction of the transmission chain, and when the crank 803 does not provide driving force or the driving force provided is opposite to the rotation direction of the central shaft 302, the transmission chain does not rotate.

[0099] This embodiment provides a forward locking mechanism and a reverse free disengagement mechanism through a one-way clutch 303. When the rider pedals forward, the human torque is transmitted to the chainring 301 to drive the vehicle. When the pedaling stops or the pedal is reversed, the chainring 301 is mechanically decoupled from the bottom bracket 302, which can reduce idle loss and accidental contact loss.

[0100] like Figure 6 As shown, in this embodiment, there are two central axis Hall effect sensors 604, including a first central axis Hall effect sensor and a second central axis Hall effect sensor. The first and second central axis Hall effect sensors are arranged in a ring around the central axis magnetic ring 603, and the relative magnetic field angle between the first and second central axis Hall effect sensors is 90 degrees.

[0101] When the central shaft 302 rotates, it drives the central shaft magnetic ring 603 to rotate. The magnetic field of the central shaft magnetic ring 603 sweeps through the first central shaft Hall and the second central shaft Hall in sequence. Based on the time and sequence of the rising edge and / or falling edge of the electrical signal output by the first central shaft Hall and the second central shaft Hall, the rotation speed and rotation direction of the central shaft 302 are obtained.

[0102] In some embodiments, there is one central Hall 604.

[0103] It should be noted that one central axis Hall 604 can only obtain the rotational speed of the central axis 302, while two central axis Hall 604s can provide higher precision rotational speed measurement and can simultaneously obtain the rotational speed and rotational direction of the central axis 302.

[0104] The central axis Hall sensor 604 can be installed as either a through-hole Hall sensor or a surface-mount Hall sensor. When the central axis Hall sensor 604 is a through-hole Hall sensor, the central axis magnetic ring 603 is magnetized radially. When the central axis Hall sensor 604 is a surface-mount Hall sensor, the central axis magnetic ring 603 is magnetized axially.

[0105] like Figure 6 As shown, in this embodiment, the two central axis Hall 604s are through-hole Hall types.

[0106] As a further limitation, the number of pole pairs of the central magnetic ring 603 shall be no less than 2 pairs and no more than 20 pairs.

[0107] Furthermore, such as Figure 6 As shown, the first circuit board is disposed within the cavity inside the first housing 101 and the second housing 102. The side of the first circuit board facing the first housing 101 includes a magnetic encoder, an MCU computing unit, a MOSFET driver chip, an external communication chip, and terminal blocks. The other side of the first circuit board is in close contact with the inner wall of the second housing 102 via thermally conductive silicone grease or a thermally conductive insulating pad, so that heat from the first circuit board can be transferred to the second housing 102 through the thermally conductive silicone grease or thermally conductive insulating pad.

[0108] like Figure 8 As shown, the power assist sprocket 401 is mounted on the power assist sprocket shaft 402 that passes through the first housing 101. The reduction gear 403 is mounted on the power assist sprocket shaft 402 via a one-way bearing 404. The motor shaft 503 of the power assist motor meshes with the reduction gear 403. When the power assist motor is driving the vehicle forward, the one-way bearing 404 is locked, and the torque of the power assist motor is transmitted sequentially through the motor shaft 503, the reduction gear 403, and the one-way bearing 404 to the power assist sprocket shaft 402 and the power assist sprocket 401. In this embodiment, a single-stage parallel shaft reduction system composed of the motor shaft 503 and the reduction gear 403 is used. A planetary reduction system can also be used. If a planetary reduction system is used, preferably, the motor shaft 503 is a sun gear and the reduction gear 403 is a planet carrier.

[0109] One end of the sprocket shaft 402 passes through the first housing 101 via a bearing, and the other end is mounted on the inner wall of the second housing 102 via a bearing.

[0110] Specifically, a wave-shaped elastic washer 107 is provided on the outer ring of the bearing between the sprocket shaft 402 and the second housing 102.

[0111] In this embodiment, the booster sprocket shaft 402 is connected to the booster sprocket 401 using a spline, and the booster sprocket 401 is axially fixed using a snap ring. The use of a spline in this embodiment aims to transmit a larger torque.

[0112] The power assist motor includes a stator 501 fixed in the inner cavity of the third housing 103, a rotor 502 coaxially arranged with the stator 501, and a motor shaft 503 rigidly connected to the rotor 502.

[0113] In this embodiment, the stator 501 is fixed in the inner cavity of the third housing 103 by a tight fit. Bearings are provided at both ends of the motor shaft 503, and the bearings at both ends are respectively mounted on the third housing 103 and the second housing 102.

[0114] Specifically, the bearing between the motor shaft 503 and the third housing 103 is disposed on the inner wall of the third housing 103, and the outer ring of the bearing is provided with a wave-shaped elastic washer 107.

[0115] like Figure 8 As shown, a helical gear 5031 is provided at one end of the motor shaft 503 facing the second housing 102. The helical gear 5031 meshes with the reduction gear 403 to drive the power sprocket shaft 402.

[0116] The direction of rotation of the helical gear 5031 satisfies the following: when the motor shaft 503 drives the reduction gear 403, the axial force generated by the meshing inhibits the relative displacement between the reduction gear 403 and the motor shaft 503 in the axial direction.

[0117] In fact, the helical gear 5031 of the motor shaft 503 can be either left-handed or right-handed. However, considering the positioning design of the motor shaft 503, the helical gear 5031 in this embodiment is set to the left-handed direction, which can avoid the relative movement of the reduction gear 403 and the motor shaft 503 in the axial direction caused by axial force.

[0118] In this embodiment, the mechanism of the one-way bearing 404 is detailed in the application number 2024226276534 filed by the applicant on October 30, 2024, which describes a one-way clutch structure for a mid-drive motor, a mid-drive motor, and a vehicle.

[0119] Specifically, when the power assist motor is driving the vehicle forward, the rotation direction of the helical gear 5031 of the power assist motor is the same as the preset rotation direction of the one-way bearing 404. The one-way bearing 404 is locked, and the torque of the power assist motor is transmitted sequentially through the motor shaft 503, the reduction gear 403, and the one-way bearing 404 to the power assist sprocket shaft 402 and the power assist sprocket 401. When the rotation direction of the helical gear 5031 of the power assist motor is different from the preset rotation direction of the one-way bearing 404, the one-way bearing 404 disengages, and the helical gear 5031 rotates independently.

[0120] As a further improvement, an oil reservoir 109 for a one-way bearing 404 is provided on the sprocket shaft 402 to store lubricating oil and continuously provide lubrication for the one-way bearing 404.

[0121] A chip-attracting permanent magnet 4031 is provided at the bottom of the cavity between the first housing 101 and the second housing 102. The chip-attracting permanent magnet 4031 is located at the bottom of the outer end face of the reduction gear 403 and is used to attract iron chips generated by the reduction gear 403 during meshing transmission, so as to reduce the wear of the reduction gear 403.

[0122] like Figure 7 As shown, a Hall plate 605 is provided in the cavity between the third housing 103 and the second housing 102. The Hall plate 605 is disposed on the second housing 102. The sensing center point of the Hall chip 6051 on the Hall plate 605 is aligned with the center axis of the permanent magnet end face on the rotor 502, and is used to measure the angle of the magnetic pole on the rotor 502.

[0123] In this embodiment, the axial distance between the sensing center point of the Hall chip 6051 and the end face of the permanent magnet on the rotor 502 is no greater than 5 mm.

[0124] Because the accuracy of measuring the angle of the magnetic poles on rotor 502 using Hall chip 6051 is low, this embodiment also provides, for example... Figure 9 The motor rotor magnetic encoder 607 is shown.

[0125] In some embodiments, a Hall effect chip 6051 and a motor rotor magnetic encoder 607 are used simultaneously to measure the angle of the magnetic poles on the rotor 502 to improve system redundancy. Failure of either one will not affect the measurement of the magnetic pole angle on the rotor 502.

[0126] A radially magnetized motor shaft magnet 606 is provided on the end face of the motor shaft 503 facing the first housing 101. A second circuit board is provided in the cavity between the first housing 101 and the second housing 102, and a motor rotor magnetic encoder 607 is provided on the second circuit board. The sensing center of the motor rotor magnetic encoder 607 is aligned with the center of the motor shaft magnet 606, and the motor rotor magnetic encoder 607 obtains the angle of the magnetic poles on the motor rotor 502 by sensing the rotation angle of the motor shaft magnet 606.

[0127] Specifically, the motor shaft magnet 606 is radially magnetized. The second circuit board is directly or indirectly mounted on the second housing 102. The axial distance between the center of the motor rotor magnetic encoder 607 and the end face of the motor shaft magnet 606 is no greater than 5 mm.

[0128] It should be noted that the second circuit board is connected to the first circuit board via cable 805 to receive instructions and transmit the angle information of the magnetic poles of rotor 502.

[0129] like Figure 10As shown, the auxiliary sprocket 701 is connected to the auxiliary sprocket shaft 7012 via a bearing, and the auxiliary sprocket shaft 7012 is fixedly connected to the first housing 101. The auxiliary sprocket 701 is used to increase the wrap angle of the chain 801 with respect to the assist sprocket 401, thereby improving the stability of power transmission.

[0130] In this embodiment, as Figure 10 As shown, the auxiliary sprocket shaft 7012 passes through the first housing 101, and its end is connected to the second housing 102. Axial positioning is achieved by a snap ring.

[0131] This embodiment also includes a temperature protection module connected to the first circuit board, comprising a circuit board temperature sensor and a motor temperature sensor. The temperature protection module limits the current output of the assist motor according to a set temperature curve, thereby achieving the function of temperature protection.

[0132] This embodiment can achieve real-time dynamic matching between the output power of the assist motor and the pedaling force of the rider, solving the problem of over-output of the assist motor caused by measurement errors in traditional systems, significantly reducing energy consumption and extending the life of components.

[0133] Example 2:

[0134] This embodiment provides a vehicle, including the centrally mounted motor 9 and chain 801 for measuring pedal force as described in Embodiment 1.

[0135] The housing of the mid-drive motor has no fewer than two mounting holes 106, and the mid-drive motor is connected to the vehicle by bolts passing through the mounting holes 106.

[0136] like Figure 12 As shown, the vehicle includes a battery, which is connected to the mid-drive motor via cable 805 to supply power to the mid-drive motor.

[0137] like Figure 12 As shown, the vehicle includes a drive wheel 802, and a flywheel 8021 is provided on the central axle 302 of the drive wheel 802. The chain 801 starts from the flywheel 8021 of the drive wheel 802, passes through the auxiliary sprocket 701, the power assist sprocket 401, the force measuring sprocket 201 and the chainring 301 in sequence, and returns to the flywheel 8021 of the drive wheel 802 to form a closed loop.

[0138] As a further improvement, a wheel speed sensor is installed on the axle of the non-drive wheel, and the wheel speed sensor is connected to the first circuit board.

[0139] like Figure 12 As shown, the vehicle also includes a pedal 804 and a crank 803. One end of the crank 803 is connected to the central shaft of the mid-mounted motor, and the other end is connected to the pedal 804.

[0140] In the riding of a conventional vehicle, the rider's pedal force is applied to the pedals, which is converted into torque on the bottom bracket 302 through the crank. The one-way clutch 303 locks, and the chainring 301 drives the chain 801 to output power.

[0141] In this embodiment, the rider's pedaling force acts on the pedal 804, which is converted into torque on the bottom bracket 302 via the crank 803. The tension of the chain 801 acts on the force-measuring sprocket 201, the outer swing arm 202 rotates around the swing arm shaft 204, and the inner swing arm 203 compresses the force-measuring spring 205 to generate a reaction force. Through a high-precision lever-type mechanical conversion mechanism and non-contact magnetic coding detection, the rotation angle of the swing arm shaft 204 is accurately obtained. Based on a preset relationship, the pedaling torque applied by the rider to the bottom bracket 302 via the pedal 804 and crank 803 is calculated. Then, based on the pedaling torque, the current output of the power assist motor is controlled to set the assist torque. This assist torque is amplified by the reduction gear 403 and applied to the chain 801 via the power assist sprocket 401, thereby achieving the effect of assisting riding.

[0142] In the description of this utility model, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In addition, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0143] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0144] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A mid-mounted motor for measuring foot pedal force, characterized in that, It includes a first housing, a second housing, and a third housing, wherein the first housing is connected to one side of the second housing, and the third housing is connected to the other side of the second housing; The outer side of the first housing is provided with a force-measuring sprocket, a toothed sprocket, and an assist sprocket; The swing arm shaft passes through the first housing via a bearing, and the swing arm shaft is connected to an inner swing arm and an outer swing arm on the inner and outer sides of the first housing, respectively. The force-measuring sprocket is connected to the outer swing arm via a bearing. A force-measuring spring is provided on the inner side of the first housing. One end of the force-measuring spring is connected to the boss on the inner side of the first housing, and the other end is connected to the inner swing arm. The outer swing arm, the swing arm shaft, and the inner swing arm form a lever mechanism with the swing arm shaft as the fulcrum; the lever mechanism is used to convert the external force on the force measuring sprocket into the rotation angle of the swing arm shaft under the reaction force of the force measuring spring. The crankshaft is mounted on the central shaft that runs through the first housing and the second housing via a one-way clutch. When the rotation direction of the central shaft is the direction that causes the vehicle to move forward, the one-way clutch is locked, and the rotational torque on the central shaft is transmitted to the crankshaft. The power assist sprocket is mounted on the power assist sprocket shaft that passes through the first housing. A reduction gear is provided in the cavity between the first housing and the second housing. The reduction gear is mounted on the power assist sprocket shaft via a one-way bearing. A power assist motor is provided in the cavity between the second housing and the third housing. The motor shaft of the power assist motor meshes with the reduction gear. When the power assist motor is driving the vehicle forward, the one-way bearing is locked, and the torque of the power assist motor is transmitted sequentially through the motor shaft, the reduction gear, and the one-way bearing to the power assist sprocket shaft and the power assist sprocket.

2. The centrally located motor for measuring foot pedal force according to claim 1, characterized in that, The end of the swing arm shaft is connected to a permanent magnet spacer via a spacer bolt. One end face of the permanent magnet spacer abuts against the inner swing arm and is used to mechanically limit the axial displacement of the inner swing arm. The other end face of the permanent magnet spacer is provided with a radially magnetized encoder magnet; A first circuit board is provided in the cavity between the first housing and the second housing, and a swing arm shaft magnetic encoder is provided on the first circuit board; The sensing center of the swing arm shaft magnetic encoder is axially aligned with the geometric center of the encoder magnet. The swing arm shaft magnetic encoder obtains the rotation angle of the swing arm shaft by sensing the rotation angle of the encoder magnet. The rotation angle of the swing arm shaft is calculated and processed by the controller of the first circuit board to obtain the magnitude of the output current of the assist motor.

3. The centrally located motor for measuring foot pedal force according to claim 1, characterized in that, A central magnetic ring is provided on the central axis; a first circuit board is provided in the cavity between the first housing and the second housing, and a central Hall effect sensor is provided on the first circuit board; The central axis Hall effect sensors are distributed around the central axis magnetic ring; When the central axis rotates, it drives the central axis magnetic ring to rotate. The magnetic field of the central axis magnetic ring sweeps across the central axis Hall, triggering a change in the electrical signal output by the central axis Hall. The electrical signal output by the central axis Hall is used to obtain the rotation speed of the central axis.

4. The centrally located motor for measuring foot pedal force according to claim 3, characterized in that, There are two central axis Hall sensors, including a first central axis Hall sensor and a second central axis Hall sensor; The first and second central axis Hall effect sensors are arranged in a ring around the central axis magnetic ring, and the relative magnetic field angle between the first and second central axis Hall effect sensors is 90 degrees. When the central axis rotates, it drives the central axis magnetic ring to rotate. The magnetic field of the central axis magnetic ring sweeps through the first central axis Hall and the second central axis Hall in sequence. The rotation speed and direction of the central axis are obtained based on the time and sequence of the rising and / or falling edges of the electrical signals output by the first and second central axis Halls.

5. The centrally located motor for measuring foot pedal force according to claim 1, characterized in that, A chip-attracting permanent magnet is provided at the bottom of the cavity between the first housing and the second housing. The chip-attracting permanent magnet is located at the bottom of the outer end face of the reduction gear and is used to attract iron chips generated by the reduction gear during meshing transmission, so as to reduce the wear of the reduction gear.

6. The centrally located motor for measuring foot pedal force according to claim 1, characterized in that, The power assist motor includes a stator fixed in the inner cavity of the third housing, a rotor coaxially arranged with the stator, and a motor shaft rigidly connected to the rotor. The motor shaft is provided with a helical gear at one end facing the second housing, and the helical gear meshes with a reduction gear to drive the power sprocket shaft. The direction of rotation of the helical gear satisfies the following: when the motor shaft drives the reduction gear, the axial force generated by the meshing inhibits the relative displacement between the reduction gear and the motor shaft in the axial direction.

7. The centrally located motor for measuring pedal force according to claim 6, characterized in that, A Hall plate is provided in the cavity between the second housing and the third housing. The Hall plate is set on the second housing. The sensing center point of the Hall chip on the Hall plate is aligned with the center axis of the permanent magnet end face on the rotor, and is used to measure the angle of the magnetic poles on the rotor.

8. The centrally located motor for measuring pedal force according to claim 6 or 7, characterized in that, The end face of the motor shaft facing the first housing is provided with a radially magnetized motor shaft magnet; A second circuit board is provided in the cavity between the first housing and the second housing, and a motor rotor magnetic encoder is provided on the second circuit board; The sensing center of the motor rotor magnetic encoder is aligned with the center of the motor shaft magnet. The motor rotor magnetic encoder obtains the angle of the magnetic poles on the motor rotor by sensing the rotation angle of the motor shaft magnet.

9. The centrally located motor for measuring foot pedal force according to claim 1, characterized in that, An auxiliary sprocket is provided on the outer side of the first housing. The auxiliary sprocket is connected to the auxiliary sprocket shaft through a bearing. The auxiliary sprocket shaft is fixedly connected to the first housing. The auxiliary sprocket is used to increase the wrap angle of the chain with respect to the assist sprocket.

10. A vehicle, characterized in that, It includes the central motor and chain for measuring pedal force as described in claim 9. The chain starts from the flywheel of the drive wheel, passes in sequence around the auxiliary sprocket, the assist sprocket, the force measuring sprocket and the chainring, and returns to the flywheel of the drive wheel to form a closed loop.

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