JP2008304032A - Transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission device to be suitably mounted on a bicycle or the like. <P>SOLUTION: The transmission device comprises rotor cams 7, 8 to be rotated at the same speed in linkage with a main shaft 2, a rocking lever 5 having an end 5B thrust in alternately opposite directions by the rotor cams 7, 8 and the other end 5C reciprocative between a first position P1 and a second position P2 around a supporting portion 5A provided between the end 5B and itself, and a crank mechanism 6 for converting the rocking motion thereof into the rotating motion of an output shaft 3. The crank mechanism 6 consists of a crank arm 61 fixed to the output shaft 3, and an articulation lever 62 articulating the front end of the crank arm and the end 5C of the rocking lever. The rotor cams 7, 8 have a plurality of arm portions 7A, 8A for thrusting the end 5B of the rocking lever in sequence. Between the main shaft 2 and the output shaft 3, a dead center releasing means 20 is provided for intermittently feeding the output shaft 3 in a predetermined rotating direction while receiving the rotation driving force of the main shaft 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a transmission device suitable for being mounted on a bicycle.

  Conventionally, as a power transmission system, a winding transmission system is well known in addition to a direct transmission system by meshing of gears. For example, as a winding transmission system, in a bicycle, a chain is wound around front and rear sprockets, and power is transmitted from the front sprocket to the rear sprocket through the chain. The front sprocket is fixed to a crankshaft supported by a frame, and a pair of left and right pedal arms are connected to the crankshaft with a phase difference of 180 degrees, and a pedal is attached to each tip. The rear sprocket is attached to the rear wheel axle via a one-way clutch. Therefore, when the left and right pedals are alternately depressed with both feet, a rotational torque represented by the product of the pedal depression force and the pedal arm length is generated on the crankshaft, and the front sprocket is rotated by the torque.

  Here, the rotational speed (number of rotations) of the rear sprocket can be changed by the diameter ratio (tooth ratio) with the front sprocket. For example, the speed increases if the diameter of the front sprocket is made larger than that of the rear sprocket.

  However, if the diameter of the front sprocket is increased, a large starting torque is required and it is difficult to start uphill, and if the diameter of the front sprocket is reduced to prevent this, high speed traveling on a flat ground becomes impossible. For this reason, bicycles with a transmission in which the rear sprocket has multiple stages with different diameters so that the chain can be changed are widely used.However, the number of sprocket stages is limited in relation to the increase in overall width. There are many cases where the chain comes off when shifting.

  On the other hand, even if the diameter of the front sprocket is increased, if the length of the pedal arm is increased, the rotational torque generated on the crankshaft also increases. Therefore, it is possible to rotate the front sprocket fixed thereto with high torque. Although it is possible, even if the length of the pedal arm is increased, it is limited to a range where the pedal does not contact the ground.

  Therefore, the sprocket is fixed to the outer periphery of the internal gear, and the length of the pedal arm connected to the crankshaft is increased through the crankshaft at an eccentric position above the axis of the sprocket, while being input to the crankshaft. There has been proposed a bicycle drive device in which the generated rotational torque is transmitted to the sprocket through a gear train interposed between the internal gear and the internal gear (for example, Patent Document 1).

JP-A-8-72778

  However, as disclosed in Patent Document 1, when the position of the crankshaft is increased to increase the length of the pedal arm, a high torque is applied to the sprocket connected to the load with a chain while preventing the pedal from interfering with the ground. However, if the pedal arm is lengthened, the vertical stroke of the foot for depressing the pedal becomes large, which makes it difficult to operate the pedal.

  Further, in Patent Document 1, power is transmitted to a sprocket from a crankshaft passed through the sprocket via a gear train including internal gears, so that it is difficult to rotate the sprocket at high speed.

  The present invention has been made in view of the circumstances as described above, and an object thereof is to provide a novel transmission device that enables high torque conduction, and when applied to a bicycle, the pedal arm is not lengthened. Thus, a large rotational torque can be generated in the front sprocket.

In order to achieve the above object, the present invention
A transmission device that includes an input rotator and an output rotator that are rotatably supported, and that transmits a rotational driving force from the input rotator to the output rotator,
A first rotor cam and a second rotor cam that rotate at the same speed in conjunction with the input rotating body;
The first rotor cam and the second rotor cam alternately press the first end in the opposite direction, and the other second end is centered on a fulcrum provided between the first end and the first position. A swing lever that is reciprocally movable between a second position;
A crank mechanism for converting the swinging motion of the swing lever into the rotational motion of the output rotating body,
The crank mechanism is
A crank arm fixed to the output rotating body;
When the second end of the swing lever reciprocates between the first position and the second position, the distal end of the crank arm and the second end of the swing lever so that the output rotator rotates once. Consisting of a chain connecting the parts,
Between the input rotator and the output rotator, a node between the crank arm and the linkage is located on a straight line passing through the second end of the swing lever and the rotation center of the output rotator. In order to prevent the rotational direction of the output rotator from becoming uncertain, dead center releasing means is provided for receiving the rotational driving force of the input rotator and intermittently feeding the output rotator in a predetermined rotational direction. Features.

  In addition, each of the first rotor cam and the second rotor cam has a plurality of arm portions that sequentially press the first end portion of the swing lever, and each of the arm portions corresponds to the first rotor cam and the second rotor cam. It is provided at equal pitches in the rotation direction.

  The dead center releasing means includes a third rotor cam that rotates in conjunction with the input rotator, a link mechanism that operates by pressing one end of the third rotor cam, and a ratchet wheel that is fixed to the output rotator. A hooking claw that engages with the ratchet wheel is attached to the link mechanism.

  According to the transmission device of the present invention, the first end of the swing lever is alternately pressed in the opposite direction by the first rotor cam and the second rotor cam that rotate at the same speed in conjunction with the input rotor, and the swing lever From the input rotator to the output rotator through the crank mechanism connected to the second end of the oscillating lever. If a pedal arm is connected to the input rotator for a bicycle, the front sprocket can be used while reducing the starting torque of the rear wheels using a small-diameter front sprocket for the output rotator. The swing lever can be rotated at a speed corresponding to the number of swings.

  In addition, there is a dead center releasing means that receives the rotational driving force of the input rotator and intermittently feeds the output rotator in a predetermined rotation direction between the input rotator and the output rotator. It can prevent body reversal.

  Further, since the first rotor cam and the second rotor cam have a plurality of arm portions provided at equal pitches in the rotation direction, the output rotation is performed by increasing the number of swings of the swing lever relative to the number of rotations of the input rotating body. The body can be rotated at high speed.

  Hereinafter, application examples of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic front view showing a configuration example of such a transmission device. In FIG. 1, reference numeral 1 denotes a fixed base plate made of a metal plate or the like, and a main shaft 2 is passed through the base plate 1 as an input rotating body, and the main shaft 2 is rotatably supported by a bearing (not shown) attached to the base plate 1. Has been.

  An output shaft 3 is rotatably attached to the base plate 1 at a position parallel to the main shaft 2 and away from the main shaft, and a sprocket 4 is fixed to the output shaft 3. The output shaft 3 and the sprocket 4 constitute an output rotating body for transmitting the rotational driving force of the main shaft 2. A swing lever 5 is provided between the output shaft 3 and the main shaft 2 as shown in FIG. The swing lever 5 is a band-like rigid material that can swing in a plane (base plate 1) orthogonal to the main shaft 2, and a central portion in the length direction is pivotally attached to the base plate 1. In FIG. 1, reference numeral 5A denotes a fulcrum portion that forms the swing center of the swing lever 5, and both end portions (the first end portion 5B and the second end portion 5C) of the swing lever 5 are centered on each other. It is designed to move in the opposite direction.

  The first end portion 5B of the swing lever 5 includes a pressure receiving pin 51 as a force point to which an external force is applied, and an arcuate guide groove 1A is formed in the base plate 1 along the movement path of the pressure receiving pin 51. Yes. And the pressure receiving pin 51 is penetrated by the guide groove 1A, and the movement guide of the pressure receiving pin 51 is performed along the guide groove 1A.

  On the other hand, the second end portion 5C of the swing lever 5 can reciprocate between a first position P1 indicated by a solid line in FIG. 1 and a second position P2 indicated by an alternate long and short dash line around the fulcrum portion 5A. The The first position P1 and the second position P2 of the second end portion 5C correspond to the movement restriction positions of the pressure receiving pins 51 at both ends of the guide groove 1A.

  Further, the second end portion 5C of the swing lever 5 is connected to the output rotating body (the output shaft 3 in this example) via the crank mechanism 6. The crank mechanism 6 includes a crank arm 61 fixed to the output shaft 3, and a linkage 62 that connects the distal end portion of the crank arm 61 and the second end portion 5 </ b> C of the swing lever 5. The crank mechanism 6 causes the output shaft 3 and the sprocket 4 to rotate once when the second end portion 5C of the swing lever 5 reciprocates between the first position P1 and the second position P2. is there.

  Therefore, if the first end 5B (pressure receiving pin 51) of the swing lever 5 is alternately pressed forward and backward to give swing motion to the swing lever 5, the second end 5C is moved to the first position P1. And the second position P2, and the sprocket 4 can be rotated by the number of reciprocations.

  1 and 2, reference numerals 7 and 8 denote a pair of rotor cams (a first rotor cam and a second rotor cam) that alternately press the pressure receiving pins 51 in opposite directions, and both the rotor cams 7 and 8 are moving paths of the pressure receiving pins 51. The two are provided so as to be rotatable with respect to each other, and both of them are rotated at the same speed in conjunction with the main shaft 2. A mechanism for rotating the pair of rotor cams 7 and 8 at the same speed in conjunction with the main shaft 2 will be described later.

  In this example, each of the pair of rotor cams 7 and 8 is a blade type having two arm portions 7A and 8A provided at a pitch of 180 degrees in the rotation direction, and one rotor cam 7 is centered on the back side of the base plate 1. Is fixed to the main shaft 2 and rotates in the same direction as the main shaft 2, and the other rotor cam 8 is attached to the base plate 1 by a pivot 8B on the front side of the base plate 1 and rotates in the direction opposite to the main shaft 2. It is.

  The rotor cams 7 and 8 cause the rocking lever 5 to rock by alternately pressing the pressure receiving pins 51 in opposite directions. While one rotor cam 7 rotates clockwise in FIG. 1, the two arm portions 7A and 7A push down the pressure receiving pin 51 one after another, while the other rotor cam 8 rotates counterclockwise in FIG. The arm 8A, 8A pushes up the pressure receiving pin 51 one after another. In this example, each of the rotor cams 7, 8 has two arms 7A, 8A and rotates at the same speed as the main shaft 2. During one rotation, the rocking lever 5 presses the pressure receiving pin 51 twice by the two rotor cams 7 and 8 and performs four rocking motions. That is, since the second end portion 5C of the swing lever 5 reciprocates between the first position P1 and the second position P2, the output shaft 3 and the sprocket 4 rotate twice, and they are moved to the main shaft 2. In contrast, the speed will be doubled.

  Here, in FIG. 1, the second end portion 5C of the swing lever 5 is at the first position P1 and the second position P2, and the node (crank pin 63) between the crank arm 61 and the linkage 62 is The pin is positioned on a straight line passing through the second end portion 5C of the swing lever 5 (the node 52 between the swing lever 5 and the linkage 62) and the center of rotation of the sprocket 4. Since it hits a dead center, unless the sprocket 4 rotates with a large inertia force, the direction of rotation cannot be determined. For this reason, the transmission apparatus includes a reverse rotation prevention mechanism that can rotate the sprocket 4 in a predetermined rotation direction (clockwise in FIG. 1) regardless of the position of the crank pin 63, which will be described later.

  Next, FIG. 3 is a schematic rear view showing the transmission. In FIG. 3, 9 is an interlocking mechanism that interlocks and rotates the pair of rotor cams 7 and 8 with the main shaft 2. The interlocking mechanism 9 sequentially meshes a plurality of (four in this example) gears 9A, 9B, 9C, and 9D. Consists of a combined gear train. Among these, the gear 9A is fixed on the same axis (main shaft 2) as the rotor cam 7, and the gear 9D is fixed on the same axis as the rotor cam 8 (a pivot 8B rotatable relative to the base plate 1). The other two gears 9B and 9C are idlers interposed between the gears 9A and 9D. However, the speed ratio between the gears 9A and 9D is set to “1”, so that the main shaft 2 and the pivot 8B rotate at the same speed, and the rotor cams 7 and 8 fixed thereto rotate at the same speed. It has become. Reference numeral 10 denotes a cover plate fixed to the base plate 1 at a predetermined interval. The rotor cam 7 is arranged between the cover plate 10 and the base plate 1, and the interlocking mechanism 9 is arranged on the cover plate 10. Yes.

  In FIG. 3, reference numeral 20 denotes dead point releasing means constituting the reverse rotation preventing mechanism. The means 20 receives the rotational driving force of the main shaft 2 and intermittently feeds the output rotating body (the output shaft 3 and the sprocket 4) in a predetermined rotational direction, which is a rotor cam 21 that rotates in conjunction with the main shaft 2. (Third rotor cam), a link mechanism 22 that is operated by pressing the one end by the rotor cam 21, and a ratchet wheel 23 that is fixed to the output shaft 3.

  The rotor cam 21 has a cross shape in which four arm portions 21 </ b> A are provided at a pitch of 90 degrees in the rotation direction, and the center portion thereof is fixed to the main shaft 2. Accordingly, the rotor cam 21 rotates at the same speed in the same direction as the main shaft 2 in conjunction with the main shaft 2.

  On the other hand, the link mechanism 22 is composed of three nodes, a bell crank 22A, an intermediate link 22B, and a swing link 22C. The center portion of the bell crank 22A is pivotally attached to the base plate 1 at the shaft portion 24, and can swing around the shaft portion 24. In particular, the bell crank 22A is urged by a spring 25 that is hung between the bell plate 22A and the cover plate 10 so that one end thereof is positioned in the track range of each arm 21A of the rotor cam 21, and the other end is connected to the intermediate link 22B. And is connected to the central portion of the swing link 22C. A stopper pin 26 regulates the return position of the bell crank 22A by the spring 25.

  Further, one end of the swing link 22 </ b> C is pivotally attached to the base plate 1 by a shaft portion 27, and can swing about the shaft portion 27. In particular, a hooking claw 28 is attached to the movable end of the swing link 22 </ b> C, and the hooking claw 28 is always in contact with the outer periphery of the ratchet wheel 23 by a biasing force of a spring 29.

  The ratchet wheel 23 is a disk whose center is fixed to the output shaft 3, and a pair of tooth portions 23 </ b> A projecting on the outer periphery of the ratchet wheel 23. It is said that.

  According to the dead center releasing means 20 as described above, when the main shaft 2 rotates in a predetermined direction (counterclockwise in FIG. 2), the rotor cam 21 rotates in the same direction while the bells are moved by the respective arm portions 21A. One end of the crank 22A is sequentially pressed. The bell crank 22A whose one end is pressed by the arm portion 21A of the rotor cam 21 is returned to the initial position by the spring 25 and then repeatedly pressed by the next arm portion 21A. The swinging motion is performed around the portion 24, and the swinging motion is transmitted to the swinging link 22C via the intermediate link 22B.

  Thus, the swing link 22C swings about the shaft portion 27. When this swings to the left in FIG. 3, the hooking claw 28 provided at the movable end engages with the tooth portion 23A of the ratchet wheel 23. Then, the output shaft 3 is intermittently fed through the ratchet wheel 23 in a predetermined rotation direction (counterclockwise in FIG. 3). Even when the swing link 22C returns to the initial position shown by the solid line in FIG. 3, the output shaft 3 is rotated counterclockwise in FIG. When the swing link 22C returns to the initial position, the hooking claw 28 gets over the next tooth portion 23A and engages with the tooth portion 23A.

  Here, the operation timing of the dead point release means 20 will be described. FIG. 4 is a graph showing the swing operation of the swing lever 5, and the hatched portion in FIG. ing. FIG. 5 shows a state where the second end portion 5C of the swing lever 5 is at the first position P1 and the crank pin 63 is at the dead center position (top dead center). As described above, the swinging motion of the swinging lever 5 is converted into the rotational motion of the output shaft 3 by the crank mechanism 6, but the crank pin 63 passes through the two dead center positions while the output shaft 3 makes one rotation. However, the intermittent feed of the output rotating body by the dead point release means 20 is performed within a period from immediately before the crank pin 63 reaches the dead point position to when it passes the dead point position.

  Specifically, as shown in FIG. 5, when the crank angle (−θ) immediately before the crankpin 63 reaches the dead center position becomes 5 to 15 degrees with reference to the dead center position of the crankpin 63, the ratchet wheel 23. The output shaft 3 begins to rotate in a predetermined rotation direction. Torque is transmitted from the ratchet wheel 23 to the output shaft 3 until the crank pin 63 passes through the dead center position. When the crank angle (θ) reaches 5 to 15 degrees, the torque is transmitted from the ratchet wheel 23 to the output shaft 3. Torque transmission is cut off. That is, when the crank angle (θ) reaches 5 to 15 degrees, the swing link 22C starts to return to the initial position. At this time, the rotation of the output shaft 3 due to the swing of the swing lever 5 The ratchet wheel 23 is rotated on the output shaft 3.

By the way, the length from the fulcrum part 5A of the swing lever 5 to the first end part 5B and the second end part 5C is L ₁ and L ₂ , respectively, and the pressing force acting on the first end part 5B is F ₁ . The force F ₂ generated at the two end portions 5C is expressed by (L ₁ × F ₁ ) / L _{2. When} L ₁ > L ₂ and F ₁ is increased, the F ₂ value is increased accordingly. Although L ₁ and L ₂ are constant, the force F ₂ generated at the second end 5C varies depending on the pressing force F ₁ at the first end 5B. In particular, as shown in FIG. 6, the pressing of the first end portion 5B of the swing lever 5 by Rotakamu 8 (pressure receiving pin 51) has a short radius r ₁ of the arm portion 8A against the pressure receiving pin 51 in the initial stage, the final stage since the radius r ₂ of the arm portions 8A is long relative to the pressure receiving pin 51 in the pressing force of the pressure receiving pin 51 by the arm portions 8A of Rotakamu 8 gradually decreases over the pressing ends from the start of pressing. The same applies to the other rotor cam 7.

Ultimately, the force F ₂ generated in the second end 5C of the swing lever 5, when the second end portion 5C has reached the first position P1 to the second position P2, i.e. the crank pin 63 in the dead center position The minimum is reached. In this regard, according to the dead point release means 20 as described above, the rotational torque is applied to the output shaft 3 through the ratchet wheel 23 before the crankpin 63 reaches the dead point position. While preventing this, a decrease in torque transmitted from the swing lever 5 to the output shaft 3 can be compensated, and torque fluctuation of the output shaft 3 can be prevented.

  Next, FIG. 7 shows an example in which the transmission apparatus is applied to a bicycle. In FIG. 7, 30 is a bicycle frame, 31 is a rear wheel, and 32 is a rear sprocket attached to the axle of the rear wheel. The transmission according to the present invention is attached to the lower part of the frame 30 in the vicinity of the rear wheel 31, and a chain 33 is wound between the sprocket 4 and the rear sprocket 32. A pair of left and right pedal arms 34 are connected to both ends of the main shaft 2 with a phase difference of 180 degrees, and a pedal 35 is attached to each end thereof.

  Here, when the pair of left and right pedals 35 are alternately depressed with both feet, the main shaft 2 generates a rotational torque having a magnitude obtained by multiplying the depression force of the pedal 35 by the length of the pedal arm 34. Thereby, when the main shaft 2 is rotated, the rotational motion is converted into the swing motion of the swing lever 5 by the pair of rotor cams 7 and 8 (only one rotor cam 8 is shown in FIG. 7) as described above. Further, the swinging motion is converted into the rotational motion of the sprocket 4 via the crank mechanism 6.

  As described above, according to the transmission apparatus, the rotational torque input to the main shaft 2 is transmitted to the output shaft 3 and the sprocket 4 through the swing lever 5 and the crank mechanism 6, so that high torque conduction is possible. The sprocket 4 can be rotated at high speed while the diameter of the sprocket 4 is reduced without changing the length of the pedal arm 34 and the starting torque of the rear wheel 31 (required torque required for starting the bicycle) is reduced.

  Although the present invention has been described above, such a transmission device is not limited to a bicycle, and can be suitably used for a transmission system of a generator or other equipment. In the above example, the first rotor cam 7 and the second rotor cam 8 are each provided with two arm portions 7A and 8A. However, the arm portions 7A and 8A may be one or three to four. When the number of the arm portions 7A and 8A is three, the output shaft 3 can be tripled with respect to the main shaft 2, and when the number is four, the output shaft 3 can be quadrupled. However, the arm portion 21A of the third rotor cam 21 is twice the number of the arm portions 7A, 8A of the first and second rotor cams 7, 8.

  Further, in the above example, the first rotor cam 7 is fixed to the main shaft 2, but this is fixed to a shaft different from the main shaft 2 like the second rotor cam 8, and gears etc. from the main shaft 2 are attached to both of the rotor cams 7, 8. The rotational driving force may be transmitted through the rotor cams 7 and 8, and the rotational speeds of the rotor cams 7 and 8 may be increased or decreased with respect to the main shaft 2. However, when the speed of the rotor cams 7 and 8 with respect to the main shaft 2 is increased, the transmission torque decreases even if the rotational speed of the output shaft 3 can be increased, and the rotor cams 7 and 8 are decelerated with respect to the main shaft 2. In this case, the rotational speed of the output shaft 3 decreases, but the transmission torque increases.

  Furthermore, in the above example, the input rotator is the main shaft 2, but the main shaft 2 may be changed to a fixed shaft, and a wheel or the like may be rotatably attached thereto as the input rotator. Further, the output rotator may be only the output shaft 3 so that an external device is connected thereto, or the output shaft 3 is changed to a fixed shaft, and a sprocket 4 or a gear or a pulley is rotatably attached to the output rotator as an output rotator. You may make it do.

Schematic front view showing a transmission device according to the present invention Explanatory drawing which shows a 1st rotor cam and a 2nd rotor cam Schematic rear view showing a transmission device according to the present invention Graph showing the swinging motion of the swing lever Explanatory drawing which shows the connection aspect of a rocking lever and an output rotary body Explanatory drawing which shows the press state of the 1st end part of a rocking lever Explanatory drawing which shows the use aspect of the transmission which concerns on this invention

Explanation of symbols

1 Base plate 2 Spindle (input rotating body)
3 Output shaft (output rotating body)
4 Sprocket (output rotating body)
5 swing lever 5A fulcrum 5B first end 5C second end 51 pressure receiving pin 6 crank mechanism 61 crank arm 62 linkage 63 crank pin 7 first rotor cam 7A arm portion 8 second rotor cam 8A arm portion 9 interlocking mechanism 20 Dead center releasing means 21 Third rotor cam 22 Link mechanism 23 Ratchet wheel 28 Hook

Claims (3)

A transmission device that includes an input rotator and an output rotator that are rotatably supported, and that transmits a rotational driving force from the input rotator to the output rotator,
A first rotor cam and a second rotor cam that rotate at the same speed in conjunction with the input rotating body;
The first rotor cam and the second rotor cam alternately press the first end in the opposite direction, and the other second end is centered on a fulcrum provided between the first end and the first position. A swing lever that is reciprocally movable between a second position;
A crank mechanism for converting the swinging motion of the swing lever into the rotational motion of the output rotating body,
The crank mechanism is
A crank arm fixed to the output rotating body;
When the second end of the swing lever reciprocates between the first position and the second position, the distal end of the crank arm and the second end of the swing lever so that the output rotator rotates once. Consisting of a chain connecting the parts,
Between the input rotator and the output rotator, a node between the crank arm and the linkage is located on a straight line passing through the second end of the swing lever and the rotation center of the output rotator. In order to prevent the rotational direction of the output rotator from becoming uncertain, dead center releasing means is provided for receiving the rotational driving force of the input rotator and intermittently feeding the output rotator in a predetermined rotational direction. Characteristic transmission device.   Each of the first rotor cam and the second rotor cam has a plurality of arm portions that sequentially press the first end portion of the swing lever, and each of the arm portions is in a rotational direction of the first rotor cam and the second rotor cam. The transmission device according to claim 1, wherein the transmission device is provided at an equal pitch.   The dead center releasing means includes a third rotor cam that rotates in conjunction with the input rotator, a link mechanism that operates by pressing one end of the third rotor cam, and a ratchet wheel that is fixed to the output rotator. The transmission device according to claim 1, wherein a hooking claw that engages with the ratchet wheel is attached to the link mechanism.

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