CN212022887U - Central shaft torsion detection sensing device - Google Patents

Abstract

The utility model discloses a middle shaft torsion detection sensing device, which comprises a middle shaft with one end fixed with a chain wheel; the device is characterized by also comprising a sensor sleeve for mounting the middle shaft, wherein one end of the sensor sleeve, which is close to the fixed chain wheel of the middle shaft, is provided with a diameter-expanded detection bearing seat, a bearing sleeved on the middle shaft is arranged in the detection bearing seat, a torsion deformation sleeve with a back surface attached with a strain gauge is clamped between the outer ring of the bearing and the inner peripheral wall of the detection bearing seat, the back surface is the surface opposite to the riding direction of the electric bicycle, the torsion deformation sleeve is divided into two arc-shaped sleeves from the axial section, the gap of the section is separated, and the strain gauge is attached to one of the arc-; the sensor sleeve is characterized by further comprising a PCB plate frame fixed on the inner wall of the sensor sleeve and a PCB fixed on the PCB plate frame and used for being electrically connected with the strain gauge, and an outgoing line is arranged on the PCB plate and led out through a hole formed in the sensor sleeve. This device simple structure, the assembly is convenient, can be more accurate acquire axis torsion, reach the purpose that promotes to ride and ride quality and ride safety to simplify production raise the efficiency.

Description

Central shaft torsion detection sensing device

Technical Field

The utility model relates to a axis torsion detects sensing device.

Background

For an electric bicycle, pedal force sensing is an important technology, and a sensing device detects the force of a person stepping on the electric bicycle in real time, generates a pedal force signal, and a controller judges the riding state (light pedaling or heavy pedaling) of a rider according to the pedal force signal, so that the power output of a driving motor is adjusted to play a role in assisting riding.

As is known, in the middle shaft transmission system of an electric bicycle, pedals are mounted on a crank, the crank is connected with a middle shaft, the middle shaft is fixedly connected with an outer chain wheel, and the chain wheel is connected with a rear wheel through a chain. Therefore, when a person steps on the pedal, the chain is tightened and applies torque force which rotates backwards to the middle shaft through the chain wheel, so that the middle shaft generates torque, and the most direct method for measuring the stepping force is to measure the middle shaft torque force. For this purpose, a number of sensors for detecting the torque of the bottom bracket axle have been provided in the prior art.

For example, a middle shaft torsion detection device adopting a hall assembly is originally designed in the industry, the core components of the middle shaft torsion detection device adopt a magnetic ring, an isolating ring, an induction coil and an elastic torsion body, and a plurality of magnetic poles which are alternately arranged in S, N poles are uniformly arranged on the magnetic ring at intervals along the circumference; the elastic twisting body is fixedly connected with the middle shaft and the isolating ring and is driven by the middle shaft to rotate, the isolating ring is sleeved on the magnetic ring, and a plurality of windows for magnetic conduction are uniformly arranged on the isolating ring at intervals along the circumference. The induction coil is fixed in the five-way pipe and is positioned at the periphery of the isolating ring for inducing the change of magnetic flux. The detection device obtains the middle shaft torsion by detecting the magnetic flux variation, and has higher sensitivity and precision even at low rotating speed. However, the middle shaft torsion detection device has the obvious defects of complex structure, more parts and complex assembly. Particularly, the isolating ring, the magnetic ring and the elastic twisting body need to be specially produced aiming at middle shaft products with different specifications, the universality is avoided, the production cost is high, and the replacement is very inconvenient once the isolating ring, the magnetic ring and the elastic twisting body are damaged.

Therefore, more detection devices in the industry at present adopt a strain gauge attached to the middle shaft to detect the torsion of the middle shaft. However, in long-term practice we have found that the following problems exist with such a sensing device using strain gauges:

1) the middle shaft is a rigid member, and the deformation effect is limited after the middle shaft is stressed, so that the strain gauge cannot well detect the deformation, and the detection sensitivity is greatly reduced. Of course, the current practice is to use strain gauges with very high sensitivity, but the price of such strain gauges is very high, which results in a great increase in the production cost of the detection device.

2) The strain gauge is attached to the middle shaft and needs to rotate along with the middle shaft, so that the circuit output of the strain gauge is connected with the PCB in an internal and external induction coil mode and then led out of the PCB, the strain gauge is complex to assemble in the five-way pipe, and the production efficiency is greatly reduced.

3) Even if an internal and external induction coil is adopted, the five-way tube still needs to be processed, for example, a hole is formed in the middle of the five-way tube to lead out a circuit, so that the detection device cannot be made into an integrated product, the production and the processing are inconvenient, and the universality is poor.

Disclosure of Invention

The utility model discloses the purpose is: the utility model provides a detection precision and higher axis torsion detection sensing device of sensitivity to simple structure, the assembly is convenient, can be more accurate acquire axis torsion, reach and promote to ride and ride quality and ensure the purpose of riding safety, simplify production raise the efficiency simultaneously.

The technical scheme of the utility model is that: a middle shaft torsion detection sensing device comprises a middle shaft which is arranged at two ends in a five-way pipe of an electric bicycle and used for mounting a crank, wherein a chain wheel is further fixed at one end of the middle shaft; the device is characterized by also comprising a sensor sleeve which is used for being arranged in the five-way pipe, wherein the middle shaft is arranged in the sensor sleeve by adopting a plurality of bearings, one end of the sensor sleeve, which is close to a fixed chain wheel of the middle shaft, is integrally provided with a diameter-expanded detection bearing seat, a set of bearings which are arranged on the middle shaft are arranged in the detection bearing seat, a torsion deformation sleeve is clamped between the outer ring of each bearing and the inner peripheral wall of the detection bearing seat, the back surface of the torsion deformation sleeve is attached with a strain gauge, the back surface is the surface opposite to the riding direction of the electric bicycle, the torsion deformation sleeve is broken into two arc sub-sleeves from the axial section, the gap at the section is separated, one arc sub-sleeve is a strain sensing application arc sub-sleeve, the strain gauge is attached to the arc sub-sleeve, and; the strain gauge is electrically connected with the PCB, and the PCB is provided with a lead-out wire which is led out through an opening arranged on the sensor sleeve.

Further, in the utility model discloses in the position that has radial attenuate is sheathe in to the branch arc with the strain response, the foil gage is attached at this position.

Furthermore, in the present invention, the strain gauge is attached to the cutting plane, which is a longitudinal plane parallel to the central axis (i.e. perpendicular to the ground), and the outer surface of the arc-shaped strain gauge is provided with an axial cutting plane.

Preferably, in the utility model discloses in the strain response is equipped with the straight plane parallel with the plane of cutting with dividing the position that the plane was cut to the corresponding surface in arc cover inner surface for with the contact of the bearing inner race that detects in the bearing frame. Because the contact between the arc surface of the bearing outer ring and the straight plane is point-surface contact, the force applied by the contact part is concentrated to increase the deformation of the strain sensing sub-arc sleeve, and the sensing precision of the strain gauge on the strain sensing sub-arc sleeve is greatly improved.

Furthermore, in the present invention, the included angle between the center axes corresponding to the arc-dividing sleeves for supporting is a, and the included angle between the center axes corresponding to the arc-dividing sleeves for strain sensing is b, wherein a is greater than or equal to b.

Further, the utility model discloses the outer end wall of detecting bearing frame supports tightly with the tip of five-way pipe, still includes lock nut, the non-one end periphery shaping that sets up the detection bearing frame of sensor sleeve is threaded for another tip of spiro union lock nut and five-way pipe supports tightly, and this lock nut is fixed extremely with the sensor sleeve with detecting the cooperation of bearing frame together on the five-way pipe.

Furthermore, in the utility model discloses in the outer end wall of detection bearing frame with fill up between the five-way pipe tip and be equipped with five-way adjusting shim, the trompil is located this outer end wall of detecting bearing frame.

Further, in the utility model discloses in the PCB grillage is telescopic support, overlaps in epaxial, and the shaping has a plurality of connecting keys in its periphery, and be equipped with on the telescopic inner wall of sensor with corresponding connecting key complex spread groove, each connecting key offsets with the wall of the spread groove after inserting the spread groove along the sensor sleeve axial, simultaneously the outer end of PCB grillage with detect in the bearing frame the bearing offsets.

Further, the utility model discloses in the axis adopts two bearings to install in the sensor sleeve, is first bearing and second bearing respectively, the non-one end that sets up the detection bearing frame of sensor sleeve is equipped with interior rank, and the epaxial shaping that corresponds has the shaft shoulder, and first bearing supports locates between this interior rank and the shaft shoulder, the second bearing is located detect in the bearing frame to it presss from both sides tightly to be equipped with the interior wall of detecting the bearing frame torsion deformation cover.

Further, in the utility model discloses in epaxial cover has from the outside and torsional deformation cover the axial retaining ring that offsets, and be equipped with the caulking groove that supplies this axial retaining ring embedding on the internal perisporium of detection bearing frame.

The principle of the utility model is that: when a person rides the bicycle, when the person treads pedals arranged on cranks at two ends of a middle shaft, chains on a chain wheel are tightened, and the chain wheel is applied to a torsion force which is axially and backwards rotated in the middle shaft, so that the middle shaft generates the torsion force and forms weak deformation bent backwards (in the direction opposite to the riding direction), the torsion force is transmitted to a strain application sub-arc sleeve of a torsion force deformation sleeve through a bearing in a detection bearing seat, and a strain foil on the torsion force sub-arc sleeve senses the torsion force and generates a torsion force sensing signal through a PCB board and then outputs the torsion force sensing signal to a controller of the electric bicycle.

The utility model provides a torsion deformation cover effect bears the application of force of bearing side and produces deformation and arouse the response of foil gage, and its itself needs certain hardness, during the manufacturing usually select the known steel, alloy steel or other metal material that satisfy certain hardness and foil gage response demand can, for example 40Cr, these materials of Cr12 all can be used for making torsion deformation cover.

The utility model has the advantages that:

generally speaking, the utility model provides a this kind of axis torsion detects sensing device's detection precision and sensitivity are higher to simple structure, the assembly is convenient, can more accurate acquire axis torsion, reach and promote to ride and ride quality and ensure the purpose of riding safety, simplify production simultaneously and improve efficiency; the specific advantages are as follows:

1) the utility model discloses the independent torsion deformation cover part that has designed specially and is close to the disc side to attaching the foil gage on it, comparing original attached in epaxial mode, the deformation effect of torsion deformation cover is better, makes the torsion deformation cover on it also more sensitive to the response of deformation, and it is also higher to detect the precision.

2) The utility model discloses an in the scheme, torsion warp the cover and is divided the arc cover for two from axial cross section department disconnection, one of them is that the strain response of attached foil gage is used and is divided the arc cover, and another then supports and uses branch arc cover, and both clearances separate mutually noninterfere, and the design objective is avoided riding the in-process to support and transmit the torsion that comes on the chain of chain wheel at the back with the pressure interference who divides bearing itself that bears on the arc cover to influence the response precision of foil gage. Therefore, after the strain inductor is applied and is independently separated from the arc-shaped sleeve, the sensitivity of the strain foil to deformation can be further improved, the detection precision is improved, and the working reliability is enhanced.

3) The utility model provides an among this kind of axis torsion detection sensing device, sensor sleeve and torsion deformation cover all are relative axis static, consequently attached in the circuit of the foil gage on torsion deformation cover need not to adopt on the mode output of interior outer coil is to the PCB board, the substitute is a simple and easy PCB grillage, has consequently simplified circuit mounting structure greatly, and has saved the cost of this part spare part of interior outer coil.

4) The utility model discloses in as the torsion deformation cover that detects the core design can all detect the torsion that the power formed of stepping on of axis both ends (the crank is pedal), and detection effect and precision are the same, need not to design two sets of sensing element and detect the torsion that the power formed is stepped on to both sides respectively like conventional technique, the structure is simple more reliable.

5) The utility model relates to a device of integration completely, through the telescopic production specification of adjustment sensor, it can be directly assembled with the five-way pipe of prevailing arbitrary standard spare, need not to do processing again and reform transform electric bicycle's frame, and it is more convenient to use, more is favorable to popularizing and applying.

Drawings

The invention will be further described with reference to the following drawings and examples:

fig. 1 is a top view structural section of the present invention;

FIG. 2 is a view of the view from A-A of FIG. 1 after 90 degrees counter-clockwise rotation;

fig. 3 is a view of the sensor sleeve of fig. 2 in isolation in combination with a torsional deformation sleeve.

Wherein: 1. a five-way pipe; 2. a crank; 3. a middle shaft; 3a, a shaft shoulder; 4. a chain wheel; 5. a sensor sleeve; 6. a bearing; 6a, a first bearing; 6b, a second bearing; 7. detecting a bearing seat; 7a, caulking grooves; 8. a torsion deformation sleeve; 8a, applying a strain induction sub-arc sleeve; 8b, arc-dividing sleeves for supporting; 9. a strain gauge; 10. a PCB board frame; 11. a PCB board; 12. an outgoing line; 13. opening a hole; 14. cutting a plane; 15. locking the nut; 16. a five-way adjusting shim; 17. an inner step; 18. an axial retainer ring; 19. a chain; 20. a straight plane.

Detailed Description

Example (b): referring to fig. 1 to 3, the specific embodiment of the present invention is described in detail as follows:

the central shaft torsion detection sensing device is an integrated device which can be directly assembled with a five-way pipe of an electric bicycle and forms a part with a conventional structure, namely a central shaft 3 for fixing cranks 2 at two ends and a chain wheel 4, and the chain wheel 4 can be fixed with the central shaft 3 by being fixed with the crank 2 at one end during actual installation as shown in figure 1. And as in the prior art, the cranks 2 at both ends are used for mounting pedals (omitted in the figure) for riding, and the chain 19 (shown in figure 2) is sleeved on the chain wheel 4 to be connected with a driving chain wheel of a rear wheel of the electric bicycle.

Remove above-mentioned structure, the utility model discloses a core improves the structure as follows:

the sensor sleeve 5 is designed to be arranged in the five-way pipe 1, the middle shaft 3 is arranged in the sensor sleeve 5 by adopting two bearings 6, and the two bearings 6 are named as a first bearing 6a and a second bearing 6b respectively. One end (the left end in the figure 1) of the sensor sleeve 5 extends out of the five-way pipe 1 during assembly, and threads are formed on the periphery of the sensor sleeve and used for being screwed with a locking nut 15 to be tightly propped against the end part of the five-way pipe 1 on the same side. Meanwhile, the end of the sensor sleeve 5 is provided with an inner step 17, a shaft shoulder 3a is correspondingly formed on the middle shaft 3, and the first bearing 6a is abutted between the inner step 17 and the shaft shoulder 3 a.

Meanwhile, as shown in fig. 1, the other end (right end in fig. 1) of the sensor sleeve 5 is the end close to the fixed chain wheel 4 of the middle shaft 3, a detection bearing seat 7 with an expanded diameter is integrally arranged on the other end, and the outer end wall of the detection bearing seat 7 is tightly abutted to the end part of the five-way pipe 1. The fixing of the sensor sleeve 5 to the five-way tube 1 is ensured by the aforementioned locking nut 15 cooperating with the detection bearing seat 7.

The second bearing 6b sleeved on the bottom bracket 3 is arranged in the detection bearing seat 7, a torsion deformation sleeve 8 is clamped between the outer ring of the second bearing 6b and the inner peripheral wall of the detection bearing seat 7, and a strain gauge 9 is attached to the back surface of the torsion deformation sleeve 8, wherein the back surface is the surface opposite to the riding direction of the electric bicycle, as shown in fig. 1. Meanwhile, the inner wall of the sensor sleeve 5 is further fixed with a PCB plate frame 10 and a PCB 11 fixed on the PCB plate frame 10, the strain gauge 9 is connected with the PCB 11 through an electric wire (not shown in the figure), and the PCB 11 is provided with a lead-out wire 12 led out through an opening 13 formed in the sensor sleeve 5.

Referring to fig. 2 and 3, the torsion deformation sleeve 8 of the present invention is divided into two arc-shaped sleeves from the axial cross section, and the gap at the cross section is separated. That is, in practice, the torsion deformation sleeve 8 in the present invention is composed of two arc-dividing sleeves, one of which is the arc-dividing sleeve 8a for strain sensing, the strain gauge 9 is attached thereto, and the other is the arc-dividing sleeve 8b for supporting;

as shown in fig. 2 and 3, the outer surface of the strain-sensing partial arc sleeve 8a is provided with an axial truncated plane 14, the truncated plane 14 is a longitudinal plane parallel to the central axis 3, and is also a radially thinned part of the strain-sensing partial arc sleeve 8a, and the strain gauge 9 is attached to the truncated plane 14. Meanwhile, the position of the inner surface of the strain sensing sub-arc-shaped sleeve 8a corresponding to the outer surface cutting plane 14 is provided with a straight plane 20 which is parallel to the cutting plane 14 and is used for contacting with the outer ring of the second bearing 6b in the detection bearing seat 7 so as to enhance the sensing. This is because the contact between the arc surface of the outer ring of the second bearing 6b and the straight plane 20 is point-surface contact, and the force applied to the contact portion concentrates to increase the deformation of the strain-sensing sub-arc sleeve 8a, thereby greatly improving the sensing accuracy of the strain gauge 9 thereon.

In addition, as shown in fig. 3, in this embodiment, the included angle between the axes of the central shafts 3 corresponding to the supporting arc-dividing sleeves 8b is a, and the included angle between the axes of the central shafts corresponding to the strain sensing arc-dividing sleeves 8a is b, where a is greater than b.

In this embodiment, a five-way adjusting shim 16 is padded between the outer end wall of the detection bearing seat 7 and the end of the five-way tube 1 so as to adjust the assembly gap, and the opening 13 for leading out the lead wire is located on the outer end wall of the detection bearing seat 7, as shown in fig. 1.

In this embodiment, the PCB panel support 10 is a sleeve-type support, and is sleeved on the middle shaft 3, three connection keys (not visible in the drawing) are distributed on the outer periphery at equal angular intervals, and connection slots (not visible in the drawing) matched with the corresponding connection keys are arranged on the inner wall of the sensor sleeve 5, each connection key is inserted into the connection slot along the axial direction of the sensor sleeve 5 and then abuts against the end wall of the connection slot, and meanwhile, the outer end of the PCB panel support 10 abuts against the bearing 6 in the detection bearing seat 7, so as to fix the PCB panel support 10, as shown in fig. 1.

As shown in fig. 1, an axial retainer ring 18 that abuts against the torsion deformation sleeve 8 from the outside is fitted around the bottom bracket 3, and a recessed groove 7a into which the axial retainer ring 18 is fitted is provided in the inner peripheral wall of the detection bearing housing 7.

The principle of the utility model is that: when a person rides the bicycle, when the person pedals the pedals arranged on the cranks 2 at the two ends of the middle shaft 3, the chains 19 on the chain wheel 4 are tightened, and the torque which is applied to the middle shaft 3 by the chain wheel 4 and rotates backwards is applied to the middle shaft 3, so that the middle shaft 3 generates torque and forms weak deformation which bends backwards (back to the riding direction), and then the torque is transmitted to the strain induction application arc-dividing sleeve 8a of the strain deformation sleeve 8 by the second bearing 6b in the detection bearing seat 7, and the strain foil 9 on the strain foil senses the strain foil and generates a torque sensing signal by the PCB 11 and then outputs the torque sensing signal to the controller of the electric bicycle.

The above-mentioned embodiments are only for illustrating the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention, which should not be construed as limiting the scope of the present invention. All modifications made according to the spirit of the main technical scheme of the present invention shall be covered within the protection scope of the present invention.

Claims (10)

1. A middle shaft torsion detection sensing device comprises a middle shaft (3) which is arranged at two ends in a five-way pipe (1) of an electric bicycle and is used for mounting a crank (2), and a chain wheel (4) is further fixed at one end of the middle shaft (3); the device is characterized by further comprising a sensor sleeve (5) which is used for being arranged in the five-way pipe (1), the middle shaft (3) is arranged in the sensor sleeve (5) by adopting a plurality of bearings (6), one end, close to the fixed chain wheel (4) of the middle shaft (3), of the sensor sleeve (5) is integrally provided with a detection bearing seat (7) with an expanded diameter, the detection bearing seat (7) is internally provided with a set of bearings (6) which are arranged on the middle shaft (3), a torsion deformation sleeve (8) is clamped between the outer ring of each bearing (6) and the inner peripheral wall of the detection bearing seat (7), the back surface of the torsion deformation sleeve (8) is attached with a strain gage (9), the back surface is the surface opposite to the riding direction of the electric bicycle, the torsion deformation sleeve (8) is divided into two arc-shaped sleeves towards the section, the gap at the section is separated from the shaft, one of the arc-shaped sleeves is a strain, the strain gauge (9) is attached to the arc-shaped sleeve, and the other arc-shaped sleeve is an arc-shaped sleeve (8 b) for supporting; the sensor comprises a sensor sleeve (5), and is characterized by further comprising a PCB plate frame (10) fixed on the inner wall of the sensor sleeve (5) and a PCB (11) fixed on the PCB plate frame (10), wherein the strain gauge (9) is electrically connected with the PCB (11), and the PCB (11) is provided with an outgoing line (12) which is led out through a hole (13) formed in the sensor sleeve (5).

2. The bottom bracket shaft torsion detecting and sensing device according to claim 1, wherein the strain sensing sub-arc sleeve (8 a) has a radially thinned portion to which the strain gauge (9) is attached.

3. The bottom bracket shaft torsion detecting and sensing device according to claim 2, wherein the strain sensing sub-arc sleeve (8 a) is provided with an axial cut plane (14) on the outer surface, the cut plane (14) is a longitudinal plane parallel to the bottom bracket shaft (3), and the strain gauge (9) is attached to the cut plane (14).

4. The bottom bracket torsion detecting and sensing device according to claim 3, characterized in that the position of the inner surface of the strain sensing sub-arc sleeve (8 a) corresponding to the outer surface cutting plane (14) is provided with a straight plane (20) parallel to the cutting plane (14) for contacting with the outer ring of the bearing (6) in the detecting bearing seat (7) to enhance the sensing.

5. The center shaft torsion detecting and sensing device according to claim 1, 2, 3 or 4, characterized in that the included angle degree of the center shaft (3) axis corresponding to the supporting arc-dividing sleeve (8 b) is a, and the included angle degree of the center shaft axis corresponding to the strain sensing arc-dividing sleeve (8 a) is b, a is larger than or equal to b.

6. The bottom bracket shaft torsion detection sensing device according to claim 1, wherein the outer end wall of the detection bearing seat (7) abuts against the end of the five-way pipe (1), the bottom bracket shaft torsion detection sensing device further comprises a locking nut (15), a thread is formed on the periphery of one end, which is not provided with the detection bearing seat (7), of the sensor sleeve (5) and used for screwing the locking nut (15) to abut against the other end of the five-way pipe (1), and the locking nut (15) and the detection bearing seat (7) are matched together to fix the sensor sleeve (5) to the five-way pipe (1).

7. The bottom bracket torsion detection sensing device according to claim 6, wherein a five-way adjusting gasket (16) is padded between the outer end wall of the detection bearing seat (7) and the end of the five-way pipe (1), and the opening (13) is located on the outer end wall of the detection bearing seat (7).

8. The central axle torsion detection sensing device according to claim 1, characterized in that the PCB panel support (10) is a sleeve type support, which is sleeved on the central axle (3), and a plurality of connection keys are formed on the outer periphery thereof, and the inner wall of the sensor sleeve (5) is provided with connection slots matched with the corresponding connection keys, each connection key is inserted into the connection slot along the axial direction of the sensor sleeve (5) and then abuts against the end wall of the connection slot, and simultaneously, the outer end of the PCB panel support (10) abuts against the bearing (6) in the detection bearing seat (7).

9. The center shaft torsion detection sensing device according to claim 1 or 8, wherein the center shaft (3) is installed in the sensor sleeve (5) by using two bearings (6), which are respectively a first bearing (6 a) and a second bearing (6 b), an inner step (17) is provided at one end of the sensor sleeve (5) not provided with the detection bearing seat (7), a shaft shoulder (3 a) is correspondingly formed on the center shaft (3), the first bearing (6 a) is abutted between the inner step (17) and the shaft shoulder (3 a), the second bearing (6 b) is located in the detection bearing seat (7), and the torsion deformation sleeve (8) is clamped between the second bearing and the inner peripheral wall of the detection bearing seat (7).

10. The bottom bracket torsion detection sensing device according to claim 1, characterized in that the bottom bracket (3) is sleeved with an axial retaining ring (18) which is abutted against the torsion deformation sleeve (8) from the outside, and the inner peripheral wall of the detection bearing seat (7) is provided with a caulking groove (7 a) for the axial retaining ring (18) to be embedded in.

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