JP2007083849A - Low-floor-type motorcycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-floor-type motorcycle capable of significantly reducing secondary vibrations of an engine, and restraining a width of the engine. <P>SOLUTION: In this low-floor-type motorcycle 10, step floors 25 for an occupant to locating legs are provided on right and left sides of a vehicle body frame 11, and an engine 14 is provided between the step floors 25. Exhaust pipes 51-53 extend from each cylinder of the engine 14, and the exhaust pipes 51-53 are collected at a collection part. The engine 14 is a straight three engine with a cylinder part 45 inclined forward. The engine 14 is provided with the forward inclined cylinders 45, and the exhaust pipes 51-53 extend downward from the cylinders 45 every cylinder. Thereafter, the exhaust pipes 51-53 are bundled so as to extend rightward of the engine 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a low-floor type motorcycle that includes a cover member that covers a vehicle body frame and that has an engine below the cover member.

There is known a low-floor type motorcycle including a cover member that covers a vehicle body frame and an engine below the cover member (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2002-79982 (FIG. 2)

In FIG. 2 of Patent Document 1, a motorcycle 1 includes a body frame 2, and an engine unit 41 (hereinafter simply referred to as an engine 41) is suspended from the body frame 2.
The engine 41 is a two-cylinder engine provided with a balancer shaft 67 (hereinafter referred to as a balance shaft 67) above the crankshaft 61 at the mating surface of the cylinder block 47 and the crankcase 48.

  The balance shaft 67 provided in such a two-cylinder engine is generally a primary balance shaft that reduces primary vibration. By providing the balance shaft 67 in the two-cylinder engine, the primary vibration of the engine 41 can be reduced.

  However, in this engine form, even if the primary vibration can be canceled by the balance shaft, the secondary vibration remains. As a result, in a low floor type motorcycle having a resin exterior part, secondary vibration generated by the engine 41 is transmitted to, for example, a cover member constituting a part of the exterior part, and the sound of the cover member or the like is transmitted. May be a factor in the occurrence of

  As a countermeasure against vibration of exterior parts, there is a method of blocking engine vibration by using a rubber mount in the engine support structure. However, in order to enable high-speed running, a member that supplements the rigidity of the vehicle is required separately. The number of parts increases.

  By the way, in order to reduce the secondary vibration, it is effective to increase the number of cylinders of the engine. When a four-cylinder engine is applied to a low floor type motorcycle, the secondary vibration can be reduced. However, if a 4-cylinder or 6-cylinder engine is applied, the width of the engine (the dimension in the vehicle width direction of the engine; the same applies hereinafter) becomes too wide, so that a low-floor type motorcycle as a scooter type vehicle can be maintained. It becomes difficult.

  A technique that can significantly reduce the secondary vibration of the engine and reduce the width of the engine is desired.

  An object of the present invention is to provide a low-floor type motorcycle that can significantly reduce the secondary vibration of the engine and can suppress the width of the engine.

  The invention according to claim 1 includes a step floor on which the occupant puts his / her feet on the left and right sides of the body frame, a cover member that covers the body frame between these step floors, and an engine below the cover member, In a low floor type motorcycle in which an exhaust pipe is extended from each cylinder of the engine and these exhaust pipes are gathered at a gathering portion, the engine is an inline three-cylinder engine in which the cylinder portion is tilted forward.

  The invention according to claim 2 is characterized in that the engine includes a balance shaft that reduces primary couple vibration.

  In the invention according to claim 3, the vehicle body frame and the step floor on which the occupant puts his / her foot on the left and right sides of the vehicle body frame are provided, and the cover member that covers the vehicle body frame is provided between the step floors. In a low-floor type motorcycle equipped with an engine, extending an exhaust pipe from each cylinder of the engine, and collecting these exhaust pipes at a collecting portion, the body frame includes an upper member extending from the head pipe to the upper side of the engine, a head And a down member extending to the side of the cylinder portion of the engine from the pipe, and the engine is supported by the lower end portion of the down member.

  The invention according to claim 4 is characterized in that the engine is directly fixed to the vehicle body frame without an elastic member.

  In the invention according to claim 1, since the engine is an in-line three-cylinder engine, for example, the displacement of each cylinder is smaller than in an in-line two-cylinder engine, and the vertical movement parts such as connecting rods and pistons of each cylinder are lightweight. In addition, by adjusting the balance weight of the crank, it is possible to reduce the primary vibration of the engine caused by the vertical movement of the piston or the like. In addition, it is possible to reduce the secondary vibration of the engine due to the left-right motion of the connecting rod, piston pin, and the like. Since secondary vibration is reduced, comfort during running can be improved.

  In addition, since secondary vibration can be reduced, for example, in a low-floor type motorcycle that frequently uses exterior parts such as a resin body cover, it is possible to reduce vibration at a frequency at which sound is likely to be generated in the exterior parts. .

By the way, even in a low-floor motorcycle as a scooter type vehicle, if a 4-cylinder or 6-cylinder engine can be applied, secondary vibration can be reduced. However, when a 4-cylinder or 6-cylinder engine is applied to a low-floor type motorcycle, it becomes difficult to maintain the form of the scooter type vehicle in order to secure the width of the engine.
In this regard, in the present invention, since the engine is an in-line three-cylinder engine, the form of the scooter type vehicle can be maintained without the engine being too wide.

Therefore, by using an in-line three-cylinder engine, secondary vibration can be greatly reduced, and a low-floor type motorcycle can be established without causing the engine to become too wide.
Furthermore, since the engine has tilted the cylinder part forward, it is possible to reduce the center of gravity of the vehicle. By reducing the center of gravity, the maneuverability can be improved.

In the invention which concerns on Claim 2, since the balance shaft for couple vibration reduction is provided, the primary couple vibration produced by the vibration phase difference of right and left can be reduced.
Since the primary couple vibration can be reduced, the amount of the primary couple vibration generated from the engine is transmitted to the vehicle body frame, and the comfort during running can be further improved.

In the invention according to claim 3, the vehicle body frame includes an upper member extending upward of the engine and a down member extending to the side of the cylinder portion, so that the rigidity of the vehicle body frame of the low floor vehicle and the engine is secured. However, the engine can be arranged at a low position.
Further, since the engine is supported by the lower end portion of the down member, the engine can be easily attached and detached.

In the invention according to claim 4, since the engine is directly fixed to the vehicle body frame, a predetermined vehicle body rigidity can be ensured as a so-called diamond type frame that uses the engine as a part of the vehicle body frame. In addition, the vibration of the engine can be made difficult to be transmitted to the body frame.
Since the joint rigidity between the engine and the body frame can be increased and the position of the engine can be lowered to optimize the position of the center of gravity, it is possible to further improve the running performance of the low floor type vehicle.
As a result, it is possible to greatly improve the comfort during traveling, particularly in high speed traveling.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. Note that “front”, “rear”, “left”, “right”, “upper”, and “lower” indicate directions viewed from the driver. The drawings are to be viewed in the direction of the reference numerals.
FIG. 1 is a right side sectional view of a low-floor type motorcycle according to the present invention. The motorcycle 10 includes a body frame 11, a head pipe 13 provided at the front end of the vehicle 12, and a body pipe 11. Upper members 16 and 16 (only reference numeral 16 on the front side) provided above the engine 14 and extending rearward from the head pipe 13 and seat rails 18 and 18 extending rearward and obliquely upward from the upper members 16 and 16 ( Only the front side reference numeral 18 is shown), the support frames 19 and 19 (only the front side reference numeral 19 are shown) for supporting these seat rails 18 and 18 from below, and the upper members 16 and 16 are branched. Same as down members 17 and 17 (only reference numeral 17 on the front side is shown) provided on the side of the cylinder block 23 of the engine 14 and extending downward. (Only the near side of the code 25.) From the top of the upper members 16 and 16 step floors 25, 25 extend rearwardly (only the front side reference numeral 26.) Floor brackets 26, 26 for placing a as a vehicle constructed out.

  A pivot shaft 28 is attached to the upper members 16, 16, a rear swing arm 31 is attached so as to be swingable up and down around the pivot shaft 28, and a rear cushion unit 32 is attached between the rear swing arm 31 and the vehicle body frame 11. .

  In the motorcycle 10, a front fork 35 is attached to the head pipe 13 so as to be steerable, a front wheel 36 is rotatably attached to a lower end of the front fork 35, a steering handle 37 is attached to an upper portion of the front fork 35, and the upper member 16 The engine 14 is disposed in a space between the rear member 17 and the down member 17, and a rear wheel 39 is rotatably attached to the rear end of the rear swing arm 31, and the engine 14 and the rear wheel 39 are driven to drive the rear wheel 39. The vehicle has a power transmission mechanism 42 including a drive shaft 41 interposed therebetween.

  That is, the motorcycle 10 includes a vehicle body frame 11, a rear swing arm 31 that is swingably attached to the vehicle body frame 11 via a pivot shaft 28, an engine 14 that is fixed to the vehicle body frame 11, and a drive shaft 41 from the engine 14. And a power transmission mechanism 42 that transmits a driving force to the rear wheel 39 via the rear wheel 39.

The main body of the engine 33 includes a crankcase 43 and a cylinder block 23 attached to the crankcase 43 so as to be tilted forward. The engine 14 is a water-cooled in-line three-cylinder engine 15 and includes a radiator portion 44 below the cylinder block 23 and behind the front wheel 36.
The cylinder block 23 includes a cylinder portion 45 having a cylindrical inner surface. The number of cylinder portions 45 is three.

The air cleaner unit 46 constituting a part of the intake system will be described.
The air cleaner unit 46 includes an air intake duct 47 provided in front of the head pipe 13, a first chamber 48 provided below the air intake duct 47, and a connection duct 50 disposed behind the first chamber 48. And a second chamber 49 provided. First, the air taken in by the air intake duct 47 is cleaned by an element (not shown) provided in the first chamber 48, then passed through the connection duct 50 and put into the second chamber 49, and finally, the second Cleaned air from the second chamber 49 is supplied to the engine 14.

  Thus, by arranging the air cleaner unit 46 in front of and behind the head pipe 13, a sufficient capacity can be secured and it can be arranged in the vicinity of the engine 14.

  Explaining the exhaust system, a first exhaust pipe 51, a second exhaust pipe 52, and a third exhaust pipe 53 are connected to a cylinder block 23 provided in the in-line three-cylinder engine 15, and these first to third exhaust pipes 51 to 53 are connected. The first to third exhaust pipes 51 to 53 are gathered at the gathering portion 54 provided behind the exhaust pipes 51, 52, 53, and the silencer 55 is connected to the rear of the gathering portion 54. .

  The cover member 61 is a member that covers a part of the vehicle 12 and also serves as a cowl member. The cover member 61 includes a front cover member 62 that covers the front portion of the vehicle body frame 11 such as the head pipe 13, an intermediate cover member 63 that is provided behind the front cover member 62, and a rear portion of the intermediate cover member 63. And a rear cover member 64 covering the rear of the vehicle 12.

  Here, the intermediate cover member 63 is a member that includes a foot passage space 65 that allows an occupant to pass his / her foot when moving up and down and includes the engine 14 below. Therefore, the engine 14 is provided below the foot passage space 65 through which the occupant passes his / her foot when moving up and down.

  Here, the step floors 25, 25 (only the reference numeral 25 on the front side is shown) are members attached to floor brackets 26, 26 that are a part of the vehicle body frame 11, and a footrest portion on which a rider puts his / her foot when traveling. It is.

That is, the plurality of exhaust pipes 51 to 53 are bundled and arranged below the step floor 25, and the gathering portion 54 that bundles the exhaust pipes 51 to 53 is arranged below the step floor 25. To do.
An exhaust valve 67 capable of restricting the flow rate of exhaust gas is provided in the vicinity of the collecting portion 54. The exhaust valve 67 is one of the constituent members of the exhaust gas control device 70.

  The exhaust gas control device 70 includes an exhaust valve 67 that adjusts an opening area according to an operation state, operating wires 71 and 72 that open and close the exhaust valve 67, a servo motor 73 that drives these operating wires 71 and 72, The control unit 74 is configured to adjust the flow rate of the exhaust gas by controlling the servo motor 73.

  76 is a link mechanism interposed between the rear cushion unit 32 and the rear swing arm 31, 77 is a fuel tank, 78 is a fuel pump, 79 is a reservoir tank of the rear cushion unit 32, 81 is a front brake unit, and 82 is a universal joint. 83 is an occupant seat, 86 is a main stand, and 87 is a helmet stored in a storage space.

  FIG. 2 is a front view for explaining the element arrangement around the engine of the low-floor motorcycle according to the present invention. The floor bracket 26 includes front sub-pipes 121 and 121 extending left and right and obliquely downward from the upper member 16. The main pipes 122, 122 extending obliquely downward and rearward from the front sub pipes 121, 121, and the rear sub pipes 123, 123 connecting the rear ends of the main pipes 122, 122 and the rear parts of the upper members 16, 16 It consists of. Then, the floors 124 and 124 are covered with the main pipes 122 and 122 to form step floors 25 and 25.

  As shown in FIG. 1, the engine 14 is an in-line three-cylinder engine 15 in which cylinder portions 45... (... indicates a plurality. The same applies hereinafter) are inclined forward. And this engine 14 is provided with cylinder part 45 ..., and after extending the exhaust pipes 51-53 downward for every cylinder from these cylinder parts 45 ..., these exhaust pipes 51-53 are attached. They are bundled and extended to the right side of the engine 14.

Since the engine 14 includes the cylinder portions 45... And the exhaust pipes 51 to 53 are extended downward from the cylinder portions 45... For each cylinder, the center of gravity of the vehicle 12 can be lowered. .
Since the center of gravity of the vehicle 12 can be lowered, maneuverability can be improved.
Further, since the engine 14 bundles the exhaust pipes 51 to 53 and extends to the left or right side of the engine 14, the exhaust pipes 51 to 53 can be easily arranged on the side of the engine 14.

Returning to FIG. 1, the engine 14 includes the cylinder portion 45 that is inclined forward, so that the engine 14 can be disposed low. Since the engine 14 can be disposed low, the cover member 61 can be disposed low, and a wide leg space 65 positioned above the cover member 61 can be secured.
In the present embodiment, the exhaust pipes 51 to 53 are bundled and extended to the right side of the engine 14. However, the exhaust pipes 51 to 53 may be bundled and extended to the left side of the engine 14.

  FIG. 3 is a cross-sectional view of the main part of the low floor type motorcycle according to the present invention. The engine 14 includes a crankcase 43 and a cylinder block 23 extending obliquely forward from the crankcase 43. The head 111 is attached, and the oil pan 112 is attached from below the crankcase 43.

A crankshaft 114 and a balance shaft 115 are provided on the mating surface 113 of the cylinder block 23 and the crankcase 43, a cam drive shaft 116 is provided in front of the balance shaft 115, and a camshaft is provided on the mating surface 118 of the cylinder block 23 and the cylinder head 111. 117 and 117 are provided. Then, gears 121 and 122 are interposed between the crankshaft 114 and the balance shaft 115, gears 123 and 124 are interposed between the balance shaft 115 and the cam drive shaft 116, and the cam drive shaft 116 and the cam shaft 117, The cam chain 125 is wound around the camshaft 117 to transmit the driving force of the crankshaft 114 to the camshaft 117.
That is, the engine 14 includes a balance shaft 115 that reduces primary couple vibration. Details of the balance shaft 115 will be described later.

A support structure of the engine 14 will be described.
The engine 14 is supported by a plurality of support portions 131a to 131c provided on the upper member 16 and a support portion 132 provided on the lower end portion 17b of the down member 17, and the support portions 131a to 131c are not interposed through an elastic member. , 132 directly.

  That is, the vehicle body frame 11 includes an upper member 16 extending from the head pipe 13 (see FIG. 1) to the upper side of the engine 14, and a down member 17 extending from the head pipe 13 to the side of the cylinder portion 45 of the engine 14. The engine 14 is supported by the support portions 131 a to 131 c and 132 including the lower end portion 17 b of the down member 17.

  Since the vehicle body frame 11 includes the upper member 16 extending above the engine 14 and the down member 17 extending to the side of the cylinder portion 45, the vehicle body frame 11 of the low-floor type vehicle and the engine 14 are secured with sufficient rigidity. The engine 14 can be arranged at a low position. By arranging the engine 14 at a low position, it is possible to improve the stability of traveling.

Further, the crankshaft 114, which is heavy in weight, is disposed above the step floor 25, the center of which is the footrest portion of the occupant.
Since the center of the crankshaft 114 is arranged above the step floor 25, the maneuverability can be improved by raising the position of the center of gravity of the engine 14 itself to some extent.
That is, by arranging the engine 14 at a low position and optimizing the position of the center of gravity of the engine 14, the running performance can be further improved.

  Further, since the engine 14 is supported by the lower end portion 17b of the down member 17, the engine 14 can be easily attached and detached.

Since the engine 14 is directly fixed to the vehicle body frame 11 without using an elastic member, a predetermined vehicle body rigidity can be ensured as a so-called diamond-type frame that uses the engine 14 as a part of the vehicle body frame 11.
By increasing the coupling rigidity between the engine 14 and the vehicle body frame 11 and lowering the arrangement of the engine 14 and optimizing the position of the center of gravity, it is possible to further improve the running performance of the low-floor type vehicle.
As a result, it is possible to greatly improve the comfort during traveling, particularly in high speed traveling.

  Note that the engine 14 may be fixed to the vehicle body frame 11 via an elastic member (rubber mount). In this case, it is possible to remove higher-order vibrations by fixing the engine 14 to the vehicle body frame 11 through an elastic member having high hardness, for example, rubber or urethane resin having a hardness of 80% or more.

4 is a sectional view taken along line 4-4 of FIG. 3. The crankshaft 114 is provided with a gear 121 that drives the balance shaft 115, and the gear 122 that meshes with and follows the gear 121 is provided on the balance shaft 115. Is provided with a gear 123 that drives the cam drive shaft 116, and a gear 124 that meshes with the gear 123 and follows the balance shaft 115 is provided on the cam drive shaft 116, and the driving force is transmitted to the cam drive shaft 116 to the cam shafts 117, 117. Cam sprocket 126 is provided.
Reference numeral 135 denotes a starter motor, which is configured such that a gear 137 created on the output shaft 136 of the starter motor 135 and a gear 138 provided on the cam drive shaft 116 mesh with each other.

  The balance shaft 115 is a member that reduces couple vibration generated in the engine (reference numeral 14 in FIG. 1).

Since the couple vibration is a moment intervening, a balance shaft 115 having a pair of eccentric loads is provided at a position separated by a predetermined amount from the center of the shaft, and the balance shaft 115 is rotated in the reverse direction with respect to the crankshaft. Counteract force vibration.
Details of the balance shaft 115 will be described in the following figures.

FIG. 5 is a view taken in the direction of arrow 5 in FIG. 4 and shows the first weight portion 141 provided in the balance shaft 115.
The first weight portion 141 forms a semi-circular portion on the shaft portion 143 to be a balance weight. That is, the first weight part 141 is attached with a first holder part 144 which is a semicircular part, and the first holder part 144 is formed with five balance weight insertion holes 145... Having a circular cross section. .. Are formed by inserting the balance weights 146... Into the balance weight insertion holes 145.
Furthermore, if the balance weights 146... Are made of a high-density material and fitted into the holder portion 144, the necessary balance can be ensured without enlarging the semicircular portion.

6 is a cross-sectional view taken along line 6-6 of FIG. 4 and shows a second weight portion 151 provided in the balance shaft 115. FIG.
The second weight portion 151 forms a balance weight by forming a semicircular portion in the shaft portion 143. That is, the second weight portion 151 is attached with a second holder portion 154 that is a semicircular portion, and five balance weight insertion holes 155... Having a circular cross section are formed in the second holder portion 154. It is formed by fitting balance weights 156... Into balance weight insertion holes 155.
Furthermore, if the balance weights 156... Are made of a high-density material and fitted into the holder portion 154, the necessary balance can be ensured without enlarging the semicircular portion.
The first weight portion 141 and the second weight portion 151 are arranged around the shaft portion 143 so as to be in opposite phases.

  Returning to FIG. 1, since the in-line three-cylinder engine 15 includes the balance shaft for couple vibration reduction, the primary couple vibration caused by the left and right vibration phase difference can be reduced. Since the primary couple vibration can be reduced, the amount of transmission of the primary couple vibration generated from the engine 14 to the vehicle body frame 11 is reduced.

Since the amount of primary couple vibration generated from the engine 14 is transmitted to the vehicle body frame 11, even if the engine 14 is directly fixed to the vehicle body frame 11, the vibration of the engine 14 is hardly transmitted to the vehicle body frame 11.
Since the vibration of the engine 14 is difficult to be transmitted to the vehicle body frame 11, the comfort during traveling can be greatly enhanced, particularly at high speeds.

The operation of the motorcycle described above will be described next.
Since the engine 14 is an in-line three-cylinder engine, for example, the displacement of each cylinder is smaller than that of an in-line two-cylinder engine, and the vertical moving parts such as connecting rods and pistons of each cylinder become lighter. By adjusting the balance weights 146 and 156 provided around the engine, the primary vibration of the engine 14 caused by the vertical movement of the piston or the like can be reduced. In addition, it is possible to reduce the secondary vibration of the engine due to the left-right motion of the connecting rod, piston pin, and the like. Since secondary vibration can be reduced, comfort during travel can be enhanced.

  In addition, since secondary vibration can be reduced, for example, in the low-floor type motorcycle 10 that frequently uses exterior parts such as the resin cover member 61, vibration at a frequency at which sound is likely to be generated in the exterior parts is reduced. Can do.

By the way, also in the low floor type motorcycle 10 as a scooter type vehicle, if a 4-cylinder or 6-cylinder engine can be applied, the secondary vibration can be reduced. However, when a 4-cylinder or 6-cylinder engine is applied to a low-floor type motorcycle, it becomes difficult to maintain the form of the scooter type vehicle in order to secure the width of the engine.
In this regard, in the present invention, since the engine 14 is an in-line three-cylinder engine, the form of the scooter type vehicle can be maintained without the engine 14 being too wide.

Therefore, by using an in-line three-cylinder engine, secondary vibration can be greatly reduced, and a low-floor type motorcycle with a reduced engine width can be established.
Furthermore, since the engine 14 tilts the cylinder portion 45 forward, the vehicle 12 can be lowered in the center of gravity. By reducing the center of gravity, the maneuverability can be improved.

  Although the balance shaft of the engine according to the present invention is applied to a motorcycle in the embodiment, it can also be applied to a four-wheeled vehicle and can be applied to a general vehicle.

  The present invention is suitable for motorcycles.

1 is a right side cross-sectional view of a low floor type motorcycle according to the present invention. FIG. 2 is a front view for explaining the element arrangement around the engine of the low floor type motorcycle according to the present invention. 1 is a cross-sectional view of a main part of a low floor type motorcycle according to the present invention. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. FIG. 5 is a view taken in the direction of arrow 5 in FIG. 4. FIG. 6 is a sectional view taken along line 6-6 of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Motorcycle, 11 ... Body frame, 13 ... Head pipe, 14 ... Engine, 15 ... Inline 3-cylinder engine, 16 ... Upper member, 17 ... Down member, 17b ... Lower end part of a down member, 25 ... Step floor, 45 ... Cylinder part 51 ... 1st exhaust pipe 52 ... 2nd exhaust pipe 53 ... 3rd exhaust pipe 54 ... Collecting part 61 ... Cover member 115 ... Balance shaft.

Claims (4)

There are step floors on which the occupants put their feet on the left and right sides of the body frame, a cover member that covers the body frame is provided between these step floors, an engine is provided below the cover member, and exhaust pipes from each cylinder of the engine In a low-floor type motorcycle in which these exhaust pipes are gathered at the gathering part,
The low-floor type motorcycle according to claim 1, wherein the engine is an in-line three-cylinder engine having a cylinder portion inclined forward.   The low-floor motorcycle according to claim 1, wherein the engine includes a balance shaft that reduces primary couple vibration.   The vehicle body frame includes an upper member extending from the head pipe to the upper side of the engine, and a down member extending from the head pipe to the side of the cylinder portion of the engine, and the lower end of the down member supports the engine. The low floor type motorcycle according to claim 1 or 2, wherein the motorcycle is a low floor type motorcycle. 4. The low floor type motorcycle according to claim 1, wherein the engine is directly fixed to a vehicle body frame without using an elastic member.

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