JP5186407B2 - In-wheel type electric vehicle - Google Patents

Description

  The present invention relates to an in-wheel type electric vehicle in which a rotating electrical machine as a drive source is accommodated in a drive wheel.

  An in-wheel type electric vehicle includes a motor (rotary electric machine) and a speed reducer in a drive wheel, and the rotation of the motor is torque-amplified by the speed reducer and transmitted to the drive wheel. In such a vehicle, it is necessary to cool the motor and lubricate gears, bearings, etc., but using an oil pump or the like is contrary to the demand for downsizing and simplification required for the in-wheel type. End up. For this reason, the rotation of a rotating member provided in the motor is used to scoop up the oil and supply the oil to a necessary location.

  As this type of driving device, for example, there is one described in Patent Document 1. In the driving device described in Patent Document 1, the oil scraped up by the rotating member is applied to the rib on the side of the case and dropped on the guide rib, and the lubricating oil is put into the rotating shaft via the oil reservoir formed by the boss. Is supplied efficiently.

JP 2001-032914 A

However, in the driving device described in Patent Document 1 described above, the oil is guided to guide the oil into the rotating shaft so that the required amount of oil can be supplied into the rotating shaft during high-speed rotation. Since the guide rib is provided, at the time of low-speed rotation, more oil than necessary is supplied into the rotary shaft by the guide rib. When more oil than necessary is supplied into the rotating shaft, there is a problem that the rotational resistance of the rotating shaft increases.
Further, even during low-speed rotation, the oil is guided by the guide ribs and guided into the rotation shaft, so that there is a problem that a stirring loss is not a little.

  Accordingly, the present invention has been made to solve the above-described problems, and an optimum amount of oil is supplied into the rotating shaft during low-speed rotation and high (medium) -speed rotation, and rotation during low-speed rotation is achieved. An object of the present invention is to provide an in-wheel type electric vehicle capable of reducing shaft rotation resistance and oil stirring loss.

The present invention, which has been made to solve the above-described problems, transmits the driving force of a rotating electrical machine including a stator wound with a coil and a rotor rotatably disposed on the inner periphery of the stator to driving wheels. At least two modes can be switched manually or automatically: an in-wheel type drive device, a first mode in which the rotating electrical machine is driven at a low speed, and a second mode in which the rotating electrical machine is driven to a high speed. and a switching device, a rotating device for rotating the driving device with the mode switching according to prior Symbol sWITCHING device, in an electric vehicle comprising the driving device is configured to rotate in conjunction with the rotary electric machine, A rotating shaft having a lubrication-necessary member that needs to be lubricated with oil disposed on an outer periphery; and a drive device case that houses the rotating electrical machine, the rotating shaft being subjected to centrifugal force to cause the lubrication-needed member An oil passage in the shaft for supplying oil; and the driving device case includes an oil reservoir for storing oil scraped up by rotation of the rotor, a boss portion supporting the rotating shaft on a side surface, and the boss And a reservoir for storing oil scraped up from the oil reservoir, and a radially extending from the boss portion to change the flow of oil scraped up from the oil reservoir. The guide rib has a guide angle, which is an angle formed by the guide rib and a horizontal plane in accordance with the rotation of the driving device by mode switching of the switching device, than in the second mode. in so as to together with the provided small, arranged in the normal rotation direction front side of the rotation shaft of the opening of the reservoir, the water in the first mode In the first mode, more than half of the oil scraped up from the oil reservoir and dropped onto the guide rib is returned to the oil reservoir without being guided to the opening of the reservoir. The flow of oil is changed, and in the second mode, the flow of oil is changed so that most of the oil scraped up from the oil reservoir and dropped onto the guide rib is guided to the opening of the reservoir . The guide angle is an angle (elevation angle) between the guide rib and the horizontal plane.

In this in-wheel type electric vehicle, in the first mode in which the rotating electrical machine is driven at a low speed, the guide angle of the guide rib provided on the side surface of the drive device case is made relatively small. As a result, the oil scraped up from the oil reservoir by the guide rib is hardly guided to the reservoir, so that more oil than necessary is not supplied to the oil passage in the rotating shaft, and the rotational resistance of the rotating shaft can be reduced. it can. Further, since the guide angle of the guide rib is relatively small, in other words, because the guide rib is laid down, oil agitation loss can be reduced.
On the other hand, in the second mode in which the rotating electrical machine is driven to high-speed rotation, the guide angle of the guide rib is made relatively large. As a result, the oil scooped up from the oil reservoir by the guide rib is guided to the reservoir, so that a sufficient amount of oil is supplied to the oil passage in the rotating shaft at the time of high (medium) speed rotation where the required amount of oil increases. Can do.

In this way, the optimum amount of oil can be supplied to the oil passage in the rotating shaft during low speed rotation and high (medium) speed rotation, and the rotational resistance and oil stirring loss of the rotating shaft during low speed rotation can be reduced. can do.
And since the angle change of a guide rib utilizes the rotation of the drive device accompanying the mode change of an electric vehicle, it can be implement | achieved by a simple structure, without adding a special apparatus newly.

Then, the guide rib, the disposed in the normal rotation direction front side of the rotation axis of the reservoir opening, that provided so as to be horizontal in the first mode.

  By arranging the guide ribs in this way, in the first mode, the guide angle of the guide ribs is 0 degree and the guide ribs are in a state of being laid down. In the second mode, since the guide angle of the guide rib can be increased as much as possible, oil can be collected efficiently, so that a sufficient amount of oil can be reliably supplied through the oil passage in the rotating shaft during high-speed rotation. it can. Thereby, efficient lubrication according to the running state can be performed.

Further , in the first mode, the guide rib causes the oil flow so that more than half of the oil scraped up from the oil reservoir and dropped onto the guide rib is returned to the oil reservoir without being guided to the opening of the reservoir. the change, in the second mode, most of the scooped up oil is added dropwise to the guide rib from said oil reservoir is Ru alter the flow of oil to be guided to the opening of the reservoir.

  By changing the oil flow with the guide ribs in this way, an efficient oil flow according to the running state can be formed. In other words, the optimum amount of oil can be supplied to the oil passage in the rotating shaft at the time of low speed rotation and high (medium) speed rotation, and the rotation resistance and oil stirring loss of the rotation shaft at the time of low speed rotation can be reduced. Can do.

  And, in the in-wheel type electric vehicle according to the present invention, in the case of automatically switching the mode, when the speed or acceleration of the vehicle becomes a predetermined value or more in the first mode, The first mode is switched to the second mode, and when the speed or acceleration of the vehicle becomes less than the predetermined value in the second mode, the second mode may be automatically switched to the first mode. .

  According to the in-wheel type electric vehicle of the present invention, as described above, the optimum amount of oil is supplied into the rotating shaft at the time of low speed rotation and high (medium) speed rotation, and the rotation shaft at the time of low speed rotation is supplied. Rotational resistance and oil stirring loss can be reduced.

It is a schematic diagram of the electric vehicle which concerns on embodiment, and has shown the low speed mode state. It is a schematic diagram of the electric vehicle which concerns on embodiment, and has shown the high-speed mode state. It is sectional drawing which shows schematic structure of a drive unit. It is a side view which shows schematic structure of an outer side case. It is a side view which shows schematic structure of an inner side case. It is a figure which shows the state of the inner side case in low speed mode. It is a figure which shows the state of the inner side case in high speed mode.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment in which an in-wheel type electric vehicle of the invention is embodied will be described in detail with reference to the drawings. In the following embodiments, an electric vehicle capable of switching between a low speed mode (first mode) and a high speed mode (second mode) will be described as an example.

Therefore, the electric vehicle according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic diagram of an electric vehicle according to an embodiment, showing a low-speed mode state. FIG. 2 is a schematic diagram of the electric vehicle according to the embodiment, and shows a high-speed mode state.
As shown in FIGS. 1 and 2, the electric vehicle 1 according to the present embodiment is a three-wheeled vehicle having two front wheels and one rear wheel. The front wheels 2 are drive wheels, and in-wheel type drive units 10 are accommodated on the left and right sides of the front wheels 2, respectively. The vehicle 1 can be switched in a traveling posture (traveling mode) between a low speed mode shown in FIG. 1 and a high speed mode shown in FIG.

  Switching of the running mode is performed by driving the turning device 6 and moving the rear wheel 3 based on a command from the mode switching device 5. Specifically, the normal mode (when stopped) is the low-speed mode, and switching from the low-speed mode to the high-speed mode is performed by moving the rear wheel 3 rearward to lengthen the wheel base. Thus, in the high speed mode, as shown in FIG. 2, the vehicle 1 is inclined slightly rearward, so that the front wheel 2 moves forward and the drive unit 10 accommodated in the front wheel 2 rotates. It has become. On the other hand, switching from the high speed mode to the low speed mode is performed by moving the rear wheel 3 forward to return the wheel base to its original length. As a result, as shown in FIG. 1, the vehicle 1 returns to the original posture, so that the front wheel 2 moves rearward and the drive unit 10 accommodated in the front wheel 2 rotates.

  The mode switching is automatically performed by the mode switching device 5. Specifically, when the vehicle speed of the vehicle 1 becomes a predetermined value (for example, about 20 to 30 km / h) or more, the low-speed mode is switched to the high-speed mode, and when the vehicle speed of the vehicle 1 falls below the predetermined value, the high-speed mode is switched to the low-speed mode. Switch to The vehicle speed is detected by a vehicle speed sensor (not shown) provided in the vehicle 1, and an output from the vehicle speed sensor is input to the mode switching device 5. Further, the above-described mode switching can also be performed by operating a mode switching switch 7 provided in the driver's seat. Note that mode switching may be performed based on acceleration (which may be detected by a G sensor or the like) instead of the vehicle speed.

  Here, the in-wheel type drive unit 10 accommodated in the front wheel 2 will be described with reference to FIGS. FIG. 3 is a sectional view showing a schematic configuration of the drive unit. FIG. 4 is a side view showing a schematic configuration of the outer case. FIG. 5 is a side view showing a schematic configuration of the inner case. FIG. 4 shows a state in which the stator and the bearing are incorporated.

  As shown in FIG. 3, the drive unit 10 is housed in a wheel rim 2 a of a front wheel (drive wheel) 2. The drive unit 10 includes a motor (rotary electric machine) 20, a planetary gear 40, and a brake device 60. The motor 20 and the planetary gear 40 are housed in an integrated case 12 made up of two split cases 12a and 12b. The integrated case 12 is provided with a vehicle attachment portion 11, and the integrated case 12 is suspended from the vehicle 1 via a suspension device assembled to the attachment portion 11.

  Here, as shown in FIG. 4, a boss 13 a for a bearing 16 that supports the output shaft 15 is formed in the center of the outer case 12 a. A first side wall 14 a for holding and fixing the stator 21 of the motor 20 is formed on the outer peripheral portion of the outer case 12 a. Furthermore, the 2nd side wall 14b is formed in the outer peripheral side of this 1st side wall 14a. The second side wall 14b is not formed on the entire circumference of the outer case 12a, but is formed only on the lower left portion (about ¼ circumference) in FIG. A space formed by the first side wall 14 a, the second side wall 14 b, and the inner case 12 b is an oil reservoir 19. An electrical wiring (connection) 21a in which power lines and neutral lines of the motor 20 are collected is accommodated in the upper part of the oil reservoir 19, and is drawn out of the outer case 12a. For this reason, even if the 2nd side wall 14b is formed in the outer peripheral side of the 1st side wall 14a, the outer diameter dimension of the drive unit 10 does not enlarge.

  As shown in FIG. 3, an output shaft 15 is rotatably supported by a boss portion 13a of the outer case 12a via a bearing 16 and protrudes outside the case. A hub 17 for fixing the wheel rim 2 a is spline-engaged with the output shaft 15 and is secured and fixed by a nut 18.

  The motor 20 is a brushless DC motor, and includes a stator 21 fixed to the outer case 12a, and a rotor 25 that is rotatably supported with a small gap (air gap) from the stator 21. . The stator 21 is composed of a large number of laminated steel plates, and includes a stator core 22 in which a large number of teeth are radially formed from an annular portion disposed on the inner diameter side, and a three-phase coil 23 wound around the teeth. Have. The stator 21 is fixed to the case 12.

  On the other hand, the rotor 25 is composed of a large number of laminated steel plates, and a rotor core 26 having permanent magnets such as rare earth magnets embedded therein at predetermined intervals in the circumferential direction and extending in the axial direction, and the rotor core 26 fixed to the outer circumferential surface. A rotor hub 27 to be supported and a rotor shaft (rotating shaft) 28 fixed to the center of the rotor hub 27 are provided. The rotor hub 27 has a flange portion 27 a extending in the inner diameter direction at the inner end thereof, and the flange portion 27 a is fixed to the rotor shaft 28. The rotor shaft 28 is supported by the output shaft 15 via a bearing 29 at one end and is supported by the inner case 12b via a bearing 30 at the other end. The rotor shaft 28 is a hollow shaft and is provided with an oil passage 28a. Oil in the oil passage 28a is supplied to the planetary gear 40, which is a member requiring lubrication, by centrifugal force generated by the rotation of the rotor shaft 28. It has come to be.

  Here, on the inner surface side of the inner case 12b, as shown in FIG. 5, a boss 13b for the bearing 30 that supports the rotor shaft 28 is formed at the center thereof, and this boss 13b is partially cut away. An opening 71 for oil introduction is formed. In the boss 13b, a reservoir 72 for storing oil introduced from the opening 71 is formed. The reservoir 72 communicates with the oil passage 28a in the rotor shaft 28.

  An oil guide rib 73 is formed so as to extend radially from the opening 71. The oil guide rib 73 is disposed on the front side of the opening 71 in the forward rotation direction of the rotor 20 and is provided to be parallel to a horizontal line A passing through the rotor shaft center O when the vehicle 1 is in the low speed mode. That is, when the vehicle 1 is in the low speed mode, a guide angle θ of an oil guide rib 73 described later is θ = 0 °. The guide angle θ is an angle (elevation angle) between the oil guide rib 73 and a horizontal plane (see FIG. 7).

  Further, ribs 74 are radially formed in an upper portion on a straight line B connecting the rotor shaft center O and the center of the opening 71 at the outer diameter portion of the inner case 12b. This rib 74 is applied to the oil guided to the rotor 25 and dropped onto the oil guide rib 73. In addition, an arcuate groove 75 for attaching the resolver 31 for detecting the rotational position (rotation angle) of the rotor 25 is formed in the inner case 12b.

  As shown in FIG. 3, the resolver 31 is attached to the side end portion of the inner case 12 b of the rotor 25. The resolver 31 includes a rotor (excitation coil) 31a and a stator (detection coil) 31b. The rotor 31a is attached to the outer periphery of a sleeve portion 27b formed in the flange portion 27a, and the stator 31b is a case cover. 13 is attached. In the present embodiment, the inner case 12b is assembled to the outer case 12a to form the integrated case 12, so that the stator 31b is disposed on the outer periphery of the rotor 31a and the resolver 31 is configured.

  Such a motor 20 is electrically connected to a controller and a battery in the vehicle body, and outputs a rotational force as a motor and also functions as a regenerative brake. The motor 20 is not limited to a brushless DC motor, and may be another synchronous or induction AC motor, or a DC motor.

  In the planetary gear 40, the sun gear S serves as an input element, the carrier CR serves as an output element, and the ring gear R serves as a fixed (reaction) element, thereby constituting a reduction gear. That is, the sun gear S is integrally formed with the rotor shaft 28, the carrier CR is integrally formed with the output shaft 15, and the ring gear R is fixed to the outer case 12a.

  Specifically, the carrier CR includes a carrier body 41 that is bulged and integrally formed at one end of the output shaft 15, and a carrier cover 42 that is integrally fixed to the carrier body 41. Two pinion shafts 43 are disposed over the main body 41 and the cover 42, and the pinions P are rotatably supported by the pinion shafts 43 via needle bearings. A ring-shaped member 46 having spline teeth 45 on the outer peripheral surface is fixed to the inner side surface of the outer case 12a by bolts 47. The ring gear R is fixed integrally with the outer case 12a by engaging the spline teeth 45 of the ring-shaped member 46 with the stepped portions of the teeth and by the snap ring 48.

  The brake device 60 includes a brake rotor 61 fixed to the hub 17 and a brake caliper 62 attached to the outer case 12a so that the outer peripheral end of the brake rotor 61 passes inside. The brake caliper 62 is disposed on the outer periphery of the outer case 12 a and includes a brake piston 63 and brake pads 64 and 65. And the brake piston 63 is accommodated in the piston case 66 comprised including a part of outer side case 12a. That is, the piston case 66 is integrated with the outer case 12a.

  In such a brake device 60, the brake piston 63 moves forward (moves to the left in FIG. 1) in the piston case 66 by rotating the brake piston 63. In the present embodiment, the brake piston 63 is rotated by a motor. When the brake piston 63 moves forward, the brake pad 64 is pushed toward the brake rotor 61 by the brake piston 63. In response to this, the brake pad 65 moves to the brake rotor 61 side. As a result, the brake rotor 61 is sandwiched between the brake pads 64 and 65 so that the front wheel 2 is braked.

  Subsequently, the operation of the electric vehicle 1 having the drive unit 10 having the above-described configuration will be described with reference to FIGS. 1, 2, 6, and 7. FIG. 6 is a diagram illustrating a state of the inner case in the low speed mode. FIG. 7 is a diagram illustrating a state of the inner case in the high speed mode.

  The vehicle 1 is in a low speed mode as shown in FIG. 1 in a stopped state (zero vehicle speed). When a current is passed through the coil 23 of the stator 21, the rotor 25 rotates and the motor 20 outputs a predetermined torque. The output torque of the motor 20 is transmitted to the planetary gear 40 via the rotor shaft 28. The planetary gear 40 receives the output torque received from the rotor shaft 28 via the sun gear S, and switches the output torque stepwise by the pinion gear P to output it to the carrier CR. As a result, the carrier CR and the hub 17 rotate at a predetermined rotational speed, and the front wheel 2 is driven. At this time, the oil is scraped up by the rotation of the rotor 25, and the motor 20 is cooled and the lubricated parts such as the planetary gear 40 are lubricated.

  As long as the driver does not operate the mode switch 7, the vehicle 1 travels in the low speed mode until the vehicle speed reaches a predetermined value. In this low speed mode, since the motor 20 is driven at a low speed, the amount of oil supplied to the members requiring lubrication such as the planetary gear 40 may be relatively small, so that it is not necessary to actively introduce oil into the reservoir 72. . Conversely, if oil is positively introduced into the reservoir 72, the rotational resistance of the rotor shaft 28 is increased and the power performance of the drive unit 10 is reduced.

  Therefore, in the drive unit 10, the inner case 12b is in the state shown in FIG. 6 in the low speed mode, and the oil guide rib 73 is substantially horizontal. For this reason, as shown by the white arrow in FIG. 6, most of the oil scraped up by the rotor 25 and hitting the rib 74 and dropped onto the oil guide rib 73 is returned to the oil reservoir 19 without being guided to the reservoir 72. . A part of the oil that falls downward by hitting the rib 74 is introduced into the reservoir 72. As a result, more oil than necessary is not supplied to the oil passage 28a, so that the rotational resistance of the rotor shaft 28 can be reduced. Further, since the guide angle θ (see FIG. 7) of the oil guide rib 73 is small (θ = 0 °), the oil stirring loss by the rotor 25 can be reduced. Accordingly, it is possible to prevent a decrease in power performance in the low speed mode.

  When the vehicle speed of the vehicle 1 reaches a predetermined value, the low speed mode is switched to the high speed mode. Specifically, based on a command from the mode switching device 5, the rotation device 6 is driven to move the rear wheel 3 rearward and the wheel base becomes longer. As a result, in the high speed mode, as shown in FIG. 2, the vehicle 1 is inclined slightly rearward, so that the front wheel 2 moves forward and the drive unit 10 accommodated in the front wheel 2 rotates. In this high speed mode, since the motor 20 is driven to high speed rotation, the amount of oil supplied to the lubrication-necessary members such as the planetary gear 40 increases, so it is necessary to actively introduce oil into the reservoir 72.

  Therefore, in the drive unit 10, the inner case 12b is in the state shown in FIG. 7 in the high speed mode, and the oil guide rib 73 rises. That is, the guide angle θ of the oil guide rib 73 is increased (θ = about 30 °). For this reason, as indicated by white arrows in FIG. 7, most of the oil that has been scraped up by the rotor 25 and dropped onto the oil guide rib 73 while being hit by the rib 74 is guided to the reservoir 72. As a result, oil can be effectively collected, introduced into the reservoir 72, and supplied to the oil passage 28 a in the rotor shaft 28. As a result, a sufficient amount of oil can be supplied to the oil passage 28a at the time of high (medium) speed rotation in which the required amount of oil increases, and the required amount of oil is supplied to the lubrication-needed members without excess or deficiency. can do.

As described above in detail, according to the electric vehicle 1 according to the present embodiment, the guide angle θ of the oil guide rib 73 is switched between the low speed mode and the high speed mode. Therefore, during low speed rotation and high (medium) speed rotation. In this case, the optimum amount of oil can be supplied to the oil passage 28a in the rotor shaft 28, and the rotational resistance of the rotor shaft 28 at the time of low speed rotation and the oil stirring loss by the rotor 25 can be surely reduced. And since the switching of the guide angle θ of the oil guide rib 73 uses the rotation of the drive unit 10 accompanying the mode switching of the electric vehicle 1, it is realized with a simple configuration without adding a special device. be able to.

  It should be noted that the above-described embodiment is merely an example and does not limit the present invention in any way, and various improvements and modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the case where the drive unit is mounted on the front wheels of the two front wheels and one rear wheel is illustrated, but the present invention is also applied to the case where the drive unit is mounted on the rear wheels. The present invention can also be applied to a vehicle having two front wheels and two rear wheels. In the above-described embodiment, there are two switchable travel modes. However, the present invention can be applied to a vehicle that can switch between three or more travel modes.

1 Electric vehicle 2 Front wheel (drive wheel)
3 Rear wheel 5 Mode switching device 6 Rotating device 7 Mode switching switch 10 Drive unit 12 Integrated case 12a Outer case 12b Inner case 13b Boss portion 15 Output shaft 19 Oil reservoir 20 Motor 21 Stator 25 Rotor 28 Rotor shaft (Rotating shaft)
28a Oil passage 29 Bearing 30 Bearing 40 Planetary gear 60 Brake device 71 Opening 72 Reservoir 73 Oil guide rib 74 Rib

Claims (2)

An in-wheel type driving device that transmits a driving force of a rotating electrical machine including a stator wound with a coil and a rotor disposed rotatably on the inner periphery of the stator to driving wheels;
A switching device capable of switching manually or automatically at least two modes of a first mode in which the rotating electrical machine is driven at a low speed rotation and a second mode in which the rotating electrical machine is driven up to a high speed rotation;
In the electric vehicle and a rotating device for rotating the driving device with the mode switching according to prior Symbol SWITCHING device,
The driving device includes:
A rotating shaft that rotates in conjunction with the rotating electrical machine and has a lubrication-necessary member that requires lubrication with oil disposed on the outer periphery;
A drive device case that houses the rotating electrical machine,
The rotating shaft has an in-shaft oil passage that supplies oil to the lubrication-required member by centrifugal force,
The drive case is
An oil reservoir for storing oil that is scraped by rotation of the rotor downward;
A boss portion that supports the rotating shaft on a side surface, a reservoir that is formed by the boss portion, communicates with the oil passage in the shaft, and accumulates oil scooped up from the oil reservoir, and extends radially from the boss portion. And a guide rib for changing the flow of oil scraped up from the oil reservoir,
The guide rib is
Along with the rotation of the driving device by mode switching of the switching device , a guide angle, which is an angle formed by a guide rib with a horizontal plane, is provided to be smaller in the first mode than in the second mode , and Arranged in front of the rotating shaft in the positive rotation direction of the opening of the reservoir, and provided to be horizontal in the first mode,
In the first mode, the oil flow is changed so that more than half of the oil scraped up from the oil reservoir and dropped on the guide rib is returned to the oil reservoir without being guided to the opening of the reservoir,
In the second mode, the flow of oil is changed so that most of the oil that has been scraped up from the oil reservoir and dropped onto the guide rib is guided to the opening of the reservoir . Electric vehicle. In the in-wheel type electric vehicle according to claim 1 ,
The switching device switches from the first mode to the second mode when the vehicle speed or acceleration exceeds a predetermined value, and from the second mode to the first mode when the vehicle speed or acceleration falls below a predetermined value. An in-wheel type electric vehicle characterized by being automatically switched to.

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