WO2020042811A1 - Center-shaft type torque sensor of electrically power-assisted bicycle - Google Patents

Abstract

A center-shaft type torque sensor of an electrically power-assisted bicycle, the sensor comprising: a center shaft (15); a chain sprocket (16) disposed at one end of the center shaft (15); a force-measuring sleeve (12) sleeved on the center shaft (15); a stress and strain sensing element (11) disposed on the force-measuring sleeve (12); a hollow shaft sleeve (24) sleeved on the other end of the center shaft (15); a center-shaft signal processing unit (25) disposed on the hollow shaft sleeve (24); a sensor cover (27) sleeved on the other end of the center shaft (15); and a processing unit (28) disposed on the sensor cover (27).

Description

Bottom shaft torque sensor of electric power-assisted bicycle Technical field

The invention relates to the technical field of electric vehicles, in particular to a central axis torque sensor of an electric power-assisted bicycle.

Background technique

Electric power-assisted bicycle is a hybrid electric vehicle driven by human and electric power. It is characterized in that the motor and the human provide driving torque at a certain ratio at the same time. This ratio is controlled by a computer program. As the speed of the bicycle changes, as the speed increases, The torque ratio provided by the electric drive system will gradually decrease to the maximum vehicle speed limited by the system. The significant difference from other electric vehicle drive systems is that the reference input of the electric power-assisted bicycle control system is the real-time tracking signals such as the torque, cadence, and speed of the cyclist acting on the pedal. The intelligent control program determines the motor The output power can achieve the riding effect of man-machine integration, which is more environmentally friendly and healthy.

The electric power-assisted bicycle adopts a hybrid mode of "manpower + electricity", which not only has the lightness and convenience of the bicycle, but also can effectively make up for the burden of uphill, upwind, and carrying the bicycle. The power provided by the power not only solves the laborious effort of cycling. At the same time, with the driving of manpower, the cruising range is large, and long-distance cycling is achieved, which has revolutionized the traditional bicycle technology.

From the composition structure, the electric power-assisted bicycle is based on a traditional bicycle, equipped with a torque sensor and a controller as its core power system. The torque sensor is used to sense the strength of the rider's pedaling, and the cadence and speed signals are used to judge. The control power system provides corresponding boosting support for the rider. Therefore, the electric power-assisted bicycle has a complicated structure and high technical content, and the torque sensor is the core of the electric power-assisted bicycle.

The prior art torque sensors for electric power-assisted bicycles include a rear axle hook claw pressure sensor, a crank disk torsion spring sensor, a pressure chain sensor, and a bottom shaft torque sensor. Among them, the rear axle claw pressure sensor has the effect of elastic hysteresis, the precision of the torsion spring sensor is poor, and the pressure chain sensor will generate an error signal due to the chain's jitter, so the riding experience of all three is relatively poor. At present, the comprehensive performance is relatively good, which is a bottom shaft torque sensor. By directly measuring the torque that the rider acts on the bottom shaft through the pedal, the signal error is small and the response is sensitive.

For the bottom shaft torque sensor, cranks and pedals are installed on both sides of the bottom shaft of the electric power-assisted bicycle. During the riding process, two feet of a person alternately pedal, and the torque is transmitted to the sprocket on the right side of the bottom shaft through the bottom shaft. In the above, the bicycle is driven forward, and the torque on the bottom axle is alternated bilaterally. The bottom shaft torque sensor is installed at the position of the five-way shaft and is mechanically coupled with the bottom shaft. Since the size space that the bottom shaft torque sensor can occupy is very small, it is very difficult to structure the electronic and mechanical components inside the bottom shaft torque sensor.

The axle torque sensors of the prior art electric power assisted bicycles are all integrated structures. The bilateral torque is measured by using a long sleeve on the axle, and the signal line is led out from the fixed casing. The integral axle torque sensor makes the force measurement system The large radial size is not conducive to the layout of components inside the force measurement system.

Summary of the Invention

The purpose of the present invention is to provide a bottom shaft torque sensor of an electric power-assisted bicycle, so as to solve the problem that the size of the bottom shaft torque sensor in the radial direction is large due to the layout of components in the bottom shaft torque sensor in the prior art.

The technical solution of the present invention is:

The invention provides a bottom shaft torque sensor of an electric power-assisted bicycle, including: a bottom shaft;

A sprocket wheel, which is mounted on one end of the bottom bracket through a first bearing;

A force-measuring sleeve is sleeved on the central shaft, the force-measuring sleeve rotates integrally with the central shaft, and the force-measuring sleeve and the sprocket disc are connected through a first clutch;

A stress-strain sensing element mounted on the force-measuring sleeve;

A hollow shaft sleeve is sleeved at the other end of the middle shaft, the hollow shaft sleeve rotates integrally with the middle shaft, and the force measuring sleeve is located between the hollow shaft sleeve and the sprocket disc;

A bottom-axis signal processing unit is mounted on the hollow shaft sleeve, the stress-strain sensing element and the bottom-axis signal processing unit are communicated through a bottom-axis wire, and the bottom-axis wire is along the bottom of the bottom shaft. The axis direction is attached to the central axis;

A sensor cover, which is sleeved on the other end of the middle shaft, and the hollow shaft sleeve is located between the sensor cover and the force measuring sleeve;

A main processing unit mounted on the sensor housing, the main processing unit and the bottom axis signal processing unit being electromagnetically connected through a pair of induction coils, and the bottom axis signal processing unit may be opposite to the The main processing unit rotates.

Preferably, a first mounting groove is provided on an end surface of the force-measuring sleeve at a side remote from the central axis, and the stress-strain sensing element is placed in the first mounting groove;

A second mounting groove is formed on an end surface of the hollow shaft sleeve facing the sensor housing, and the central shaft signal processing unit and a second induction coil of a pair of induction coils are placed in the second mounting groove. And the bottom axis signal processing unit and the second induction coil are connected by a wire;

A third mounting groove is formed on an end surface of the sensor cover facing one side of the hollow shaft sleeve, the main processing unit and a first induction coil of a pair of induction coils are placed in the third mounting groove, and The main processing unit and the first induction coil are connected by a wire;

The second induction coil is rotatable relative to the first induction coil, and when the second induction coil is rotated to a position opposite to the first induction coil, the first induction coil and the second induction coil There is a predetermined distance between the coils.

Preferably, the force-measuring sleeve and the bottom bracket are fitted with a clearance, and the force-measuring sleeve and the bottom bracket are connected by a key.

Preferably, the hollow shaft sleeve is screwed with the hollow shaft through a first screw, and the first screw passes through the hollow shaft sleeve and is screwed into the hollow shaft.

Preferably, the bottom bracket wire is attached on the outer surface of the bottom bracket; or,

The bottom bracket wire is clamped in a fourth mounting slot opened on the outer surface of the bottom bracket; or,

The bottom bracket wire is penetrated in a mounting hole provided along the axial direction of the bottom bracket, and two ends of the mounting hole communicate with the outer surface of the bottom bracket, respectively.

Preferably, it further comprises: a motor input shaft and a motor output shaft, wherein the motor input shaft drives the motor output shaft to rotate through a gear transmission device;

The motor input shaft sleeve is arranged on the bottom shaft, the motor input shaft and the bottom shaft are fitted with a clearance, and the motor input shaft is located between the hollow shaft sleeve and the force measuring sleeve;

The motor output shaft is supported on the motor input shaft through a second bearing, and the motor output shaft is sleeved on the force measuring sleeve and fits with the force measuring sleeve; the motor output shaft Connected to the sprocket disc by a second clutch.

Preferably, it further comprises: a sensor cover, a motor end cover, a housing and a bearing cover,

One end of the sensor cover and the sensor cover are connected by a second screw, and the other end of the sensor cover, one end of the motor end cover and one end of the housing are screwed by a third screw; the motor The other end of the end cover is sleeved on the motor input shaft through a third bearing, and is mounted on the hollow shaft sleeve through a fourth bearing sleeve; the other end of the housing and one end of the bearing cover pass through the first Four screws are screwed, and the housing is supported on the motor input shaft through a fifth bearing; the other end of the bearing cover is supported on the sprocket disk through a sixth bearing.

Preferably, a first spring retaining ring and a second spring retaining ring are sleeved on the center shaft to form an interference fit with the center shaft, and the first spring retaining ring fits the first bearing away from One side of the force-measuring sleeve, and the second spring retaining ring is attached to a side of the hollow shaft sleeve far from the force-measuring sleeve;

The sprocket plate is sleeved with a bearing circlip which forms an interference fit with the sprocket plate, and the bearing circlip is disposed in abutment with the sixth bearing.

The beneficial effects of the present invention are:

The torque sensor of the central axis of the electric power assisted bicycle provided by the present invention uses a force measuring sleeve installed on the central axis to measure the torque signal, so that the structure of the torque measurement system is compact, and the bilateral pedaling of the electric power assisted bicycle can be accurately measured. Moment. The entire torque measuring system adopts a split structure, so that the radial size of the middle part in the torque measuring system is small, and it meets the structural requirements of the gear transmission. At the same time, the electrical components in the torque measurement system are connected by wired and wireless sensing methods, which has flexible layout and convenient installation and maintenance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structural diagram of the present invention;

FIG. 2 is a three-dimensional structure diagram of a center axis; FIG.

Figure 3 is the three-dimensional structure diagram of the force-measuring sleeve; 1—sensor cover; 2—third screw; 3—motor end cover; 4—third bearing; 5—center shaft wire; 6—shell; 7—motor output Shaft; 8- fifth bearing; 9- bearing spring; 10- sixth bearing; 11- stress-strain sensing element; 12- force measuring sleeve; 121- first mounting groove; 13- first bearing; 14- A spring retaining ring; 15-center shaft; 151-fourth mounting groove; 16-sprocket disc; 17-bearing cover; 181-first clutch; 182-second clutch; 19-fourth screw; 20-key; 21—the second bearing; 22—the motor input shaft; 23—the fourth left bearing; 24—the hollow shaft sleeve; 25—the central shaft signal processing unit; 26—the sensor cable; 27—the sensor cover; 28—the main processing unit 29- second spring retaining ring; 30- first screw; 31- first induction coil; 32- second induction coil; 33- second screw.

detailed description

Referring to FIGS. 1 to 3, the present invention provides a bottom shaft torque sensor of an electric power-assisted bicycle, which includes: a bottom shaft 15; a sprocket wheel 16 which is mounted on one end of the bottom shaft 15 through a first bearing 13; and a force measuring sleeve. 12, which is sleeved on the central shaft 15, the force measuring sleeve 12 and the central shaft 15 rotate integrally, and the force measuring sleeve 12 and the sprocket disc 16 are connected through a first clutch 181; the stress and strain sensing element 11, which is installed on On the force-measuring sleeve 12; a hollow shaft sleeve 24 is sleeved on the other end of the shaft 15; the hollow shaft sleeve 24 rotates integrally with the shaft 15; the force-measuring sleeve 12 is located between the hollow shaft sleeve 24 and the sprocket wheel 16 The center axis signal processing unit 25 is installed on the hollow shaft sleeve 24. The stress and strain sensing element 11 and the center axis signal processing unit 25 are communicated through the center axis wire 5 and the center axis wire 5 is along the axis of the center axis 15. The direction is attached to the center shaft 15; the sensor cover 27 is sleeved on the other end of the center shaft 15; the hollow shaft sleeve 24 is located between the sensor cover 27 and the force measuring sleeve 12; the main processing unit 28 is installed On the sensor cover 27, the main processing unit 28 and the bottom shaft signal processing unit 25 are electrically connected by a pair of induction coils. Connection, the signal processing unit 25 and the central axis relative to the main processing unit 28 is rotated.

Since the stress-strain sensing element 11 that collects the torque generated by the rotation of the bottom shaft 15 and the bottom shaft signal processing unit 25 and the main processing unit 28 that process the collected torque signals are separately provided, the three are no longer integrated. On the same component, in this way, the radial space occupied by the components for torque collection and processing in the center axis torque force measurement system can be reduced, and the size of the force measurement system in the radial direction can be reduced. The radial space occupied in the system is reduced, which facilitates the layout of other components inside the force measurement system.

Both ends of the bottom bracket 15 are provided with inclined surfaces and screw holes for fixing the bottom bracket. The bottom bracket is fixed to the bottom bracket 15 by screwing. When the user steps on the pedal, the bottom shaft 15 rotates with the rotation of the pedal, and the force measuring sleeve 12 that rotates integrally with the bottom shaft 15 drives the sprocket disc 16 to rotate through the first clutch 181. The rotation drives the chain and the rear wheel to rotate, thereby realizing the movement of the bicycle. In order to realize the integral rotation between the bottom bracket 15 and the force-measuring sleeve 12, in this application, the bottom bracket 15 and the force-measuring sleeve 12 are clearance-fitted, and the two are connected by a key 20 to realize transmission.

The stress-strain sensing element 11 installed on the force-measuring sleeve 12 is specifically a stress-strain sensor. When the bottom shaft 15 is rotated by the foot pedal, a torque is generated on the bottom shaft 15 and is mounted on the force-measuring sleeve 12. The stress-strain sensing element 11 on the top generates a torque signal through the deformation of the material. The generated torque signal is transmitted to the bottom shaft signal processing unit 25 through the bottom shaft wire 5. The bottom shaft signal processing unit 25 processes the received torque signal to obtain The torque value is transmitted to the main processing unit 28 through the electromagnetic induction between a pair of induction coils. The main processing unit 28 transmits it to the electric booster through the sensor cable 26 passing through the sensor cover 27 The control system of the bicycle. The control system compares the measured torque value with the pre-stored torque value to determine whether the motor is required to drive. If the motor drive is required, input the corresponding target output torque value to the motor so that the motor outputs the target torque. Value for output.

In order to achieve the fixing of the hollow shaft sleeve 24 on the bottom shaft 15, the hollow shaft sleeve 24 and the bottom shaft 15 are screwed together by a first screw 30. The first screw 30 passes through the hollow shaft sleeve 24 and is screwed into the bottom shaft 15.

In order to achieve the fixation of the stress-strain sensing element 11, in the present application, referring to FIG. 3, a first mounting groove 121 is provided on an end surface of the force-measuring sleeve 12 on a side away from the center shaft 15, and the stress-strain sensing element 11 is disposed at In a mounting groove 121, the stress-strain sensing element 11 is clamped in the first mounting groove 121. One end of the central axis wire 5 is connected to the stress-strain sensing element 11 and is attached to the force measuring sleeve 12 and the center. The shaft 15 is routed to the bottom shaft signal processing unit 25 mounted on the hollow shaft sleeve 24. In order to fix the bottom shaft signal processing unit 25 and the main processing unit 28, referring to FIG. 1, a second mounting groove is provided on an end surface of the hollow shaft sleeve 24 facing the sensor cover 27. The bottom shaft signal processing unit 25 and a The second induction coil 32 of the induction coil is placed in the second installation slot, and the central axis signal processing unit 25 and the second induction coil 32 are connected by a wire; the end surface of the sensor cover 27 facing the hollow shaft sleeve 24 is opened There is a third mounting slot, the main processing unit 28 and the first induction coil 31 of the pair of induction coils are placed in the third mounting slot, and the main processing unit 28 and the first induction coil 32 are connected by a wire; the second induction coil 32 The first induction coil 31 is rotatable relative to the first induction coil 31. When the second induction coil 32 is rotated to a position opposite to the first induction coil 31, there is a predetermined distance between the first induction coil 31 and the second induction coil 32. The signal communication between the central axis signal processing unit 25 and the main processing unit 28 adopts a wireless signal transmission method by electromagnetic induction between a pair of induction coils, reducing the wiring harness setting in the force measurement system.

For the bottom bracket wire 5, since it needs to be routed from one end of the bottom bracket 15 to the other end of the bottom bracket 15, there are various wiring methods on the bottom bracket 15. For example, the bottom bracket wire 5 is attached to the bottom bracket. On the outer surface of the shaft 15, a limiting groove for limiting the bottom bracket wire 5 is provided on the outer surface of the force measuring sleeve 12, so that the bottom bracket wire 5 can be prevented from moving on the bottom bracket 15; or, The bottom bracket wire 5 is clamped in the fourth mounting groove 151 formed on the outer surface of the bottom bracket 15 to limit the position of the bottom bracket wire 5 on the bottom bracket 15 and at the same time, it is not set on the bottom bracket. The arrangement position of other components on 15 causes interference; or, the bottom bracket wire 5 is passed through the mounting hole provided on the bottom bracket 15 in the axial direction, and the two ends of the mounting hole are communicated to the outer surface of the bottom bracket 15, respectively. Limitation of the bottom bracket wire 15 can be achieved, and interference with other components mounted on the bottom bracket 15 can be avoided.

Preferably, referring to FIG. 1, for the center-shaft torque sensor of the electric power-assisted bicycle in the present application, it further includes: a motor input shaft 22 and a motor output shaft 7. The motor input shaft 22 drives the motor output shaft 7 to rotate through a gear transmission device. ; The motor input shaft 22 is sleeved on the bottom shaft 15, the motor input shaft 22 and the bottom shaft 15 are clearance-fitted, the motor input shaft 22 is located between the hollow shaft sleeve 24 and the force measuring sleeve 12; the motor output shaft 7 passes through the second bearing 21 is supported on the motor input shaft 22, and the motor output shaft 7 is sleeved on the force measuring sleeve 12 and clearance fits with the force measuring sleeve 12; the motor output shaft 7 is connected to the sprocket disc 16 through the second clutch 182.

Among them, it is determined in the control system of the electric power-assisted bicycle that a motor drive is required, and it sends a signal to the motor to cause the motor to output a driving torque. In this way, the motor input shaft 22 rotates and the speed is converted by the gear transmission, so that the motor output shaft 7 Rotating, the motor output shaft 7 drives the sprocket wheel 16 to rotate through the second clutch 182, which in turn drives the chain and wheels to rotate, thereby realizing the movement of the bicycle.

Preferably, referring to FIG. 1, the central axis torque sensor of the electric power-assisted bicycle further includes: a sensor cover 1, a motor end cover 3, a housing 6, and a bearing cover 17. One end of the sensor cover 1 and the sensor cover 27 pass through a second screw 33. Connection, the other end of the sensor cover 2, one end of the motor end cover 3 and one end of the housing 6 are screwed by a third screw 2; the other end of the motor end cover 3 is sleeved on the motor input shaft 22 through a third bearing 4, And the fourth bearing 23 is sleeved on the hollow shaft sleeve 24; the other end of the housing 6 and one end of the bearing cover 17 are screwed by a fourth screw 19, and the housing 6 is supported on the motor input shaft 22 through a fifth bearing 8. ; The other end of the bearing cover 17 is supported on the sprocket disc 16 through a sixth bearing 10.

Referring to FIG. 1, a first spring retaining ring 14 and a second spring retaining ring 29 are sleeved on the bottom bracket 15 to form an interference fit with the bottom bracket 15. The first spring retaining ring 14 fits on the first bearing 13 away from the measuring force. On one side of the sleeve 12, the second spring retaining ring 29 fits on the side of the hollow shaft sleeve 24 away from the force measuring sleeve 12; the sprocket disk 16 is sleeved with a bearing card which forms an interference fit with the sprocket disk 16. The spring 9, the bearing retaining spring 9 and the sixth bearing 10 are disposed in close contact with each other.

The purpose of setting the first spring retaining ring 14, the second spring retaining ring 29, and the bearing retaining spring 9 described above is to limit the positions of the bearings that are attached to each other to prevent the bearings from moving.

In addition, in the present invention, for the gear transmission device between the motor input shaft 22 and the motor output shaft 7, a planetary gear transmission method may be adopted to realize the transmission between the motor input shaft 22 and the motor output shaft 7.

The torque sensor of the central axis of the electric power-assisted bicycle provided by the present invention measures the torque signal by using the force measuring sleeve 12 installed on the central shaft 15, so that the structure of the torque measuring system is compact, and the bilateral pedaling during the riding of the electric-powered bicycle can be accurately measured Stepping torque. The entire torque measurement system adopts a split structure, which makes the radial dimension of the middle part of the torque measurement system small, which meets the structural requirements of the gear transmission. At the same time, the electrical components in the torque measurement system are connected by wired and wireless sensing methods, which has flexible layout and convenient installation and maintenance.

Claims (8)

A mid-axis torque sensor for an electric power-assisted bicycle, comprising: a mid-axis (15); A sprocket wheel (16), which is mounted on one end of the bottom bracket (15) through a first bearing (13); The force measuring sleeve (12) is sleeved on the central shaft (15), the force measuring sleeve (12) and the central shaft (15) rotate integrally, and the force measuring sleeve (12) ) Is connected with the sprocket disc (16) through a first clutch (181); A stress-strain sensing element (11), which is mounted on the force-measuring sleeve (12); A hollow shaft sleeve (24) is sleeved on the other end of the middle shaft (15), the hollow shaft sleeve (24) and the middle shaft (15) rotate integrally, and the force measuring sleeve (12) Located between the hollow shaft sleeve (24) and the sprocket disc (16); a middle shaft signal processing unit (25), which is mounted on the hollow shaft sleeve (24), and the stress-strain sensing element ( 11) The center axis signal processing unit (25) communicates with the center axis wire (5), and the center axis wire (5) is attached to the center axis of the center axis (15). On shaft (15); A sensor cover (27) is sleeved on the other end of the middle shaft (15), and the hollow shaft sleeve (24) is located between the sensor cover (27) and the force measuring sleeve (12) between; A main processing unit (28) mounted on the sensor cover (27), the main processing unit (28) and the bottom-axis signal processing unit (25) being electromagnetically connected through a pair of induction coils, and The bottom axis signal processing unit (25) is rotatable relative to the main processing unit (28). The bottom shaft torque sensor of the electric power-assisted bicycle according to claim 1, characterized in that a first mounting groove (12) is provided on an end surface of the force measuring sleeve (12) on a side away from the bottom shaft (15). 121), the stress-strain sensing element (11) is placed in the first mounting groove (121); A second mounting groove is provided on an end surface of the hollow shaft sleeve (24) facing the sensor cover (27), the middle shaft signal processing unit (25) and a second induction coil of a pair of induction coils (32) placed in the second mounting slot, and the bottom shaft signal processing unit (25) and the second induction coil (32) are connected by a wire; A third mounting groove is formed on an end surface of the sensor cover (27) facing the hollow shaft sleeve (24), the main processing unit (28) and a first induction coil (31) of a pair of induction coils ) Is placed in the third mounting slot, and the main processing unit (28) and the first induction coil (32) are connected by a wire; The second induction coil (32) is rotatable relative to the first induction coil (31). When the second induction coil (32) is rotated to a position where the first induction coil (31) is opposite, There is a predetermined distance between the first induction coil (31) and the second induction coil (32). The bottom shaft torque sensor of an electric power-assisted bicycle according to claim 1, characterized in that a clearance fit is provided between the force measuring sleeve (12) and the bottom shaft (15), and the force measuring sleeve (12) ) And the bottom bracket (15) are connected by a key (20). The bottom shaft torque sensor of the electric power-assisted bicycle according to claim 1, wherein the hollow shaft sleeve (24) and the bottom shaft (15) are screwed together by a first screw (30), and the first A screw (30) passes through the hollow shaft sleeve (24) and is screwed into the middle shaft (15). The bottom shaft torque sensor of the electric power-assisted bicycle according to claim 1, wherein the bottom shaft wire (5) is attached to the outer surface of the bottom shaft (15); or, The bottom bracket wire (5) is clamped in a fourth mounting slot (151) formed on the outer surface of the bottom bracket (15); or, The bottom bracket wire (5) passes through a mounting hole provided in the bottom bracket (15) along the axial direction, and two ends of the mounting hole communicate with the outer surface of the bottom bracket (15), respectively. The bottom shaft torque sensor of an electric power-assisted bicycle according to any one of claims 1 to 5, further comprising: a motor input shaft (22) and a motor output shaft (7), wherein the motor input shaft (22) passes A gear transmission device drives the motor output shaft (7) to rotate; The motor input shaft (22) is sleeved on the middle shaft (15), the motor input shaft (22) and the middle shaft (15) are fitted with a clearance, and the motor input shaft (22) is located in the Between the hollow shaft sleeve (24) and the force measuring sleeve (12); The motor output shaft (7) is supported on the motor input shaft (22) through a second bearing (21), and the motor output shaft (7) is sleeved on the force measuring sleeve (12), and The clearance is matched with the force measuring sleeve (12); the motor output shaft (7) is connected with the sprocket disc (16) through a second clutch (182). The center axle torque sensor of an electric power-assisted bicycle according to claim 6, further comprising: a sensor cover (1), a motor end cover (3), a housing (6), and a bearing cover (17), One end of the sensor cover (1) and the sensor cover (27) are connected by a second screw (33), the other end of the sensor cover (2), one end of the motor end cover (3), and One end of the housing (6) is screwed by a third screw (2); the other end of the motor end cover (3) is sleeved on the motor input shaft (22) through a third bearing (4), and A fourth bearing (23) is sleeved on the hollow shaft sleeve (24); the other end of the housing (6) and one end of the bearing cover (17) are screwed together by a fourth screw (19), The housing (6) is supported on the motor input shaft (22) through a fifth bearing (8); the other end of the bearing cover (17) is supported on the sprocket disc through a sixth bearing (10) (16) on. The bottom shaft torque sensor of an electric power-assisted bicycle according to claim 7, characterized in that the bottom shaft (15) is sleeved with a first spring retaining ring (14) which forms an interference fit with the bottom shaft (15). ) And a second spring retaining ring (29), the first spring retaining ring (14) is attached to a side of the first bearing (13) away from the force measuring sleeve (12), and the second A spring retaining ring (29) fits on a side of the hollow shaft sleeve (24) away from the force measuring sleeve (12); The sprocket plate (16) is sleeved with a bearing circlip (9) which forms an interference fit with the sprocket plate (16), the bearing circlip (9) and the sixth bearing (10) Fitting settings.

Images