JP2006015785A - Driving device for electric automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a driving device for an electric automobile, to reduce the production cost, and at the same time, to increase durability of a driving motor. <P>SOLUTION: A housing 12 which is fixed to a car body is arranged in a wheel, and in the housing 12, a rotary case 18 is freely rotatably fitted. The housing 12 is partitioned into a motor housing chamber 24 on the external side and a retarding mechanism chamber 23 on the internal side by the rotary case 18. To the outside of the rotary case 18, a rotor 25 is fixed, and on the inside of the housing 12, a stator 26 which constitutes an electric motor 13 together with the rotor 25 is fixed while facing the rotor 25. In the rotary case 18, a planetary gearing mechanism 14 equipped with a sun gear 31, an orbit gear 32 and a carrier 33 is incorporated. An inputting element of the planetary gearing mechanism 14 is connected with the rotary case 18, an outputting element is connected with an output shaft 15 which is fixed to the wheel, and a fixing element is fixed to the housing 12. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a drive device for an electric vehicle in which a wheel is driven by an electric motor incorporated in a wheel on which a tire is mounted.

  As described in Patent Documents 1 and 2, a differential case provided between left and right drive shafts respectively connected to left and right drive wheels as a drive device for an electric vehicle in which wheels are driven by an electric motor. In this case, the electric motor is mounted to transmit the motor power to the left and right drive wheels via the differential mechanism. In this case, the electric motor is disposed between the left and right drive wheels. As described above, as a method of arranging the electric motor between the left and right drive wheels, there is one in which the left and right drive wheels can be driven by separate electric motors, as described in Patent Document 3.

In addition, as described in Patent Document 4, as a drive device for an electric vehicle, there is one in which an electric motor is incorporated in a wheel on which a tire is mounted. A speed reduction mechanism for amplifying the motor torque is incorporated. In the drive device described in this document, a gear reduction mechanism formed by constant meshing of external gears and an electric motor are arranged in series in the output shaft direction inside the wheel, and the rotational output of the electric motor is It is transmitted to the wheel via a gear reduction mechanism.
JP-A-6-339248 JP-A-7-156673 JP-A-5-169991 JP-A-8-99538

  As described above, when an electric motor is disposed between the left and right drive wheels in addition to the differential mechanism, a motor space must be secured outside the drive shaft, and the mounting ability of the drive device to the vehicle is improved. I can't. On the other hand, when the electric motor is incorporated in the wheel, it is not necessary to mount a differential mechanism. However, as disclosed in Patent Document 4, the electric motor and the speed reduction mechanism are arranged side by side in the axial direction. As a result, the axial length of the drive device increases, and the drive device protrudes outside from the wheel. Further, when an external gear is used for the speed reduction mechanism, 5 to 6 bearings including a motor support are required, and a gear meshing reaction force is generated, so a bearing with a large capacity (size) is required. End up. In addition, lubricating oil for lubricating the external gear that meshes with the motor rotor enters the motor side, making it difficult to ensure insulation, and the durability of the motor is lower than when used in air. End up.

  An object of the present invention is to reduce the size and production cost of a drive device for an electric vehicle.

  Another object of the present invention is to improve the durability of an electric motor that drives an electric vehicle.

  An electric vehicle drive device according to the present invention includes a housing that is disposed in a wheel on which a tire is mounted and is fixed to a vehicle body, and that is rotatably mounted in the housing, and a cylindrical portion and both ends of the cylindrical portion. An electric motor comprising a rotating case having an end plate portion provided therein and defining a speed reduction mechanism chamber inside; a stator attached to the inside of the housing; and a rotor attached to the outside of the cylindrical portion; a sun gear and a ring gear And a planetary gear mechanism that includes an input element connected to the rotating case, an output element connected to the wheel, and a fixed element connected to the housing, and is incorporated in the reduction mechanism chamber. It is characterized by having.

  An electric vehicle drive device of the present invention includes a first sun gear, a first ring gear, and a first carrier, which are connected to the rotating case, an input element, an output element, and a fixed element connected to the housing. And a second sun gear, a second ring gear, and a second carrier, which are connected to the output element of the first stage planetary gear train. The planetary gear mechanism is constituted by an element, an output element coupled to the wheel, and a second stage planetary gear train constituting a fixed element coupled to the housing.

  The drive device for an electric vehicle according to the present invention is characterized in that a hollow shaft portion that supports a bearing between the end plate portion of the rotating case and the housing is provided.

  According to the present invention, the housing fixed to the vehicle body is disposed in the wheel, the planetary gear mechanism as the speed reduction mechanism is accommodated in the rotating case rotatably mounted in the housing, the outer side of the rotating case, the housing, By attaching the electric motor between the two, the electric motor and the speed reduction mechanism are arranged in the radial direction, so that the dimension in the axial direction of the drive device can be reduced, and the mountability to the vehicle can be improved. .

  According to the present invention, the planetary gear mechanism in which the meshing reaction force in the radial direction is suppressed as compared with the external gear is used as the speed reduction mechanism. The rotating body can be supported, the capacity of the bearing itself can be reduced, and the production cost can be reduced.

  According to the present invention, the lubricating oil does not leak from the speed reduction mechanism chamber that is formed inside the rotating case and into which the lubricating oil is injected, into the motor housing chamber that is provided outside the rotating case. It is possible to prevent the lubricating oil from adhering to the motor and to improve the durability of the motor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each of the illustrated embodiments, common members are denoted by the same reference numerals.

  FIG. 1 is a skeleton diagram showing an electric vehicle drive apparatus according to a first embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing a main part of the electric vehicle drive apparatus shown in FIG. A housing 12 fixed to the vehicle body is disposed inside a wheel 11 on which the tire 10 is mounted, and an electric motor 13 as a drive source is incorporated in the housing 12. A planetary gear mechanism 14 for amplifying the rotational torque is arranged inside the motor 13, and the amplified rotational torque is transmitted to the wheel 11 via an output shaft 15 connected to the planetary gear mechanism 14. Thus, the tire 10 is driven to rotate.

  The housing 12 has a cylindrical portion 12a and end plate portions 12b and 12c provided at both ends thereof. The housing 12 is divided into, for example, two parts, and can be assembled by combining the two parts. The output shaft 15 protrudes outside from one end plate portion 12c and is connected to the radial portion of the wheel 11. The other end plate portion 12b has a support shaft 16 coaxially with the output shaft 15. It is fixed. The support shaft 16 protrudes toward the output shaft 15, and the small-diameter end portion 15 a of the output shaft 15 enters the recess formed in the end portion of the support shaft 16 as shown in FIG. 2. An oil seal 17 is mounted between the one end plate portion 12c and the output shaft 15.

  A rotating case 18 is rotatably mounted in the housing 12, and the rotating case 18 is assembled to a cylindrical portion 18a, an end plate portion 18b integrated with one end thereof, and the other end portion of the cylindrical portion 18a. And an end plate portion 18c to be fixed. The hollow shaft portion 19 is integrally provided on one end plate portion 18b, and the hollow shaft portion 20 is integrally provided on the other end plate portion 18c. A bearing 21 is mounted between the cylindrical portion provided on one end plate portion 12 b of the housing 12 and the hollow shaft portion 19, and the cylindrical portion provided on the other end plate portion 12 c of the housing 12 is hollow. A bearing 22 is mounted between the shaft portion 20. The rotating case 18 is rotatably supported in the housing 12 through these bearings 21 and 22.

  The housing 12 is partitioned into a speed reduction mechanism chamber 23 inside the rotation case 18 and an external motor housing chamber 24 by a rotation case 18 that is rotatably incorporated in the housing 12. A rotor 25 is attached to the outer side of the cylindrical portion 18 a of the rotating case 18, and a stator 26 that constitutes the electric motor 13 by the rotor 25 is attached to the inner side of the housing 12 so as to face the rotor 25. A coil 27 is wound around the iron core of the stator 26, and a magnet is incorporated in the rotor 25.

  The planetary gear mechanism 14 incorporated in the speed reduction mechanism chamber 23 is a single pinion type, and a sun gear 31, a ring gear 32 coaxial with the sun gear 31, and a pinion gear 34 that always meshes with the sun gear 31 and the ring gear 32 are rotatably mounted. And a carrier 33. In the case shown in FIGS. 1 and 2, the sun gear 31 is connected to the rotary case 18 by spline coupling to serve as an input element, and the ring gear 32 is provided with a boss portion that is spline coupled to the output shaft 15. The output element is fixed to the outer periphery of the connecting plate 35 and connected to the output shaft 15 via the connecting plate 35. A carrier body 36 is integrally provided at the end of the support shaft 16, and the carrier 33 is constituted by the carrier body 36 and an annular plate 37 disposed to face the carrier body 36, and is fixedly coupled to the housing 12. It is an element. The carrier 33 is provided with a pinion support shaft 38 whose both ends are fixed to the carrier body 36 and the annular plate 37, and the pinion gear 34 is rotatably supported on the pinion support shaft 38.

  As described above, in the planetary gear mechanism 14 shown in FIGS. 1 and 2, the carrier 33 is a fixed element, the sun gear 31 is an input element, the ring gear 32 is an output element, and the carrier 33 is By fixing, the pinion gear 34 that always meshes with the sun gear 31 and the ring gear 32 rotates around the pinion support shaft 38 without revolving around the sun gear 31.

  A rotating case 18 is rotatably mounted inside the housing 12 fixed to the vehicle body, and the electric motor 13 including a rotor 25 and a stator 26 is interposed between the cylindrical portion 18a of the rotating case 18 and the cylindrical portion 12a of the housing 12. And the planetary gear mechanism 14 is incorporated in the rotary case 18, and the electric motor 13 and the planetary gear mechanism 14 are shifted in the radial direction and are arranged on the same plane in the radial direction. Therefore, it is possible to suppress an increase in the axial direction of the drive device for a vehicle, and it is possible to improve the mounting property on the vehicle.

  Lubricating oil for lubricating the meshing and sliding portions of the members constituting the planetary gear mechanism 14 is injected into the speed reduction mechanism chamber 23. As shown in FIG. The rotating case 18 to be formed serves as a partition wall so that the lubricating oil does not enter the motor housing chamber 24. As a result, the lubricating oil does not enter the motor 13 side and the insulation is not lowered, and the motor 13 can be used in the air by flowing the cooling air into the motor housing chamber 24. Can be improved.

  Next, the power transmission path of the electric vehicle drive device shown in FIGS. 1 and 2 will be described. When the rotor 25 is rotationally driven by energization control to the stator 26, the rotating case 18 to which the rotor 25 is attached and the sun gear 31 connected to the rotating case 18 start to rotate in conjunction with each other. Since the carrier 33 is fixed to the housing 12, the pinion gear 34 that always meshes with the sun gear 31 does not revolve around the sun gear 31 but rotates to amplify the rotational torque of the sun gear 31 and transmit it to the ring gear 32. The ring gear 32 is rotated by the rotation of the pinion gear 34, and the amplified rotational torque is transmitted to the output shaft 15 via the connecting plate 35. The output shaft 15 is connected to the wheel 11 and can directly rotate the tire 10. In FIG. 1, members to which rotational torque is transmitted are indicated by thick lines.

  If the planetary gear mechanism 14 is used as a speed reduction mechanism for amplifying the rotational torque in this way, the meshing reaction force in the radial direction is suppressed as compared with the case where an external gear is used for the speed reduction mechanism. As shown in FIG. 2, the rotor 25 and the rotating case 18 can be supported by the two bearings 21 and 22. By suppressing the meshing reaction force, the capacity (size) of the bearings 21 and 22 themselves can be reduced, the number of the bearings 21 and 22 incorporated can be reduced, and the production cost can be reduced. When a thrust reaction force is generated, a thrust bearing may be appropriately incorporated.

  FIG. 3 is a skeleton diagram showing an electric vehicle drive device according to a second embodiment of the present invention, and FIG. 4 is a skeleton diagram showing an electric vehicle drive device according to a third embodiment of the present invention. is there. In FIGS. 3 and 4, members to which rotational torque is transmitted are indicated by thick lines.

  Which of the sun gear 31, the ring gear 32, and the carrier 33 constituting the planetary gear mechanism 14 incorporated in the speed reduction mechanism chamber 23 is a fixed element, an input element, and an output element is determined by amplifying the input rotational torque and outputting the output shaft 15 Can be freely selected as long as they are transmitted to, and the combination of these elements can be a plurality of patterns. In the case shown in FIG. 3, the ring gear 32 is a fixed element, the sun gear 31 is an input element, and the carrier 33 is an output element. In the case shown in FIG. 4, the sun gear 31 is a fixed element, the ring gear 32 is an input element, and the carrier 33 is an output element. In any of the first to third embodiments, the member constituting the fixing element is fixed to the housing 12 by the support shaft 16, and the member as the input element is connected to the rotating case 18 and serves as the output element. The member is connected to the output shaft 15. In the case shown in FIG. 3, the support shaft 16 is a hollow shaft, and the hollow support shaft 16 is loosely inserted outside the output shaft 15.

  FIG. 5 is a skeleton diagram showing a drive device for an electric vehicle according to a fourth embodiment of the present invention, and FIG. 6 is a longitudinal sectional view showing a main part of the drive device for an electric vehicle shown in FIG. In FIG. 5, members to which rotational torque is transmitted are indicated by thick lines. In the embodiment shown in FIGS. 1 to 4, the planetary gear mechanism 14 incorporated in the speed reduction mechanism chamber 23 is one stage, but in the case shown in FIG. 5, the planetary gear mechanism 14 is the first stage. The second planetary gear train is composed of a stage planetary gear train 14a and a second planetary gear train 14b.

  The first-stage planetary gear train 14a includes a sun gear 31a, a ring gear 32a coaxial with the sun gear 31a, and a carrier 33a on which a pinion gear 34a that always meshes with the sun gear 31a and the ring gear 32a is rotatably mounted. The second stage planetary gear train 14b includes a sun gear 31b, a ring gear 32b coaxial with the sun gear 31b, and a carrier 33b on which a pinion gear 34b that always meshes with the sun gear 31b and the ring gear 32b is rotatably mounted. Both planetary gear trains 14a and 14b are each a single pinion type.

  In the case shown in FIG. 5, in the first stage planetary gear train 14 a, the carrier 33 a is a fixed element that is fixed to the housing 12, and the sun gear 31 a is an input element that is connected to the rotating case 18. Yes. On the other hand, in the second stage planetary gear train 14b, the carrier 33b is a fixed element fixed to the housing 12 together with the carrier 33a, and the sun gear 31b is connected to the ring gear 32a that is an output element of the planetary gear train 14a. The ring gear 32b is an output element connected to the output shaft 15.

  As shown in FIG. 6, the second-stage carrier 33b is formed integrally with the support shaft 16 as in the case shown in FIG. 2, whereas the first-stage carrier body 36a has a support shaft. 16, both carriers 33a and 33b are fixed elements. In order to input rotational torque to the first stage sun gear 31a, the hollow shaft portion 19 of the rotating case 18 is splined to the sun gear 31a. In order to transmit the rotational torque to the output shaft 15, the second-stage ring gear 32 b is fixed to a connecting plate 35 b that is splined to the output shaft 15. Further, in order to connect the first-stage output element and the second-stage input element, the first-stage ring gear 32a and the second-stage sun gear 31b are coupled by a coupling plate 35a. The first stage carrier 33a is formed by a carrier body 36a and an annular plate 37a, and a pinion support shaft 38a is fixed to the carrier 33a. Similarly, the second stage carrier 33b is formed by a carrier body 36b and an annular plate 37b, and a pinion support shaft 38b is fixed to the carrier 33b.

  As described above, by incorporating the planetary gear mechanism 14 as the speed reduction mechanism in two stages, the reduction ratio of the rotational torque can be increased as compared with the case where the planetary gear mechanism 14 is one stage. In addition, a wide range of gear ratios can be realized depending on which of the sun gear, the ring gear, and the carrier is a fixed element, an input element, and an output element.

  FIGS. 7 to 14 are skeleton diagrams showing electric vehicle driving apparatuses according to fifth to twelfth embodiments of the present invention. 7 to 14, members to which rotational torque is transmitted are indicated by thick lines. As the power transmission path for amplifying the rotational torque when the single pinion type planetary gear mechanism 14 has one stage, there are three power transmission paths indicated by bold lines in FIGS. 1, 3, and 4, respectively. . Each of the fourth to twelfth embodiments shown in FIGS. 5 to 14 is configured by combining two stages of planetary gear trains having three power transmission paths in one stage. A street power transmission path is realized.

  5 to 8, the carrier 33a is a fixed element and the sun gear 31a is an input element among the three elements constituting the first stage planetary gear train 14a. The ring gear 32a is an output element of the planetary gear train 14a. In the case shown in FIG. 7, among the three elements constituting the second stage planetary gear train 14b, the ring gear 32b is a fixed element, and the sun gear 31b is an input element. The carrier 33b is an output element. On the other hand, in the case shown in FIG. 8, among the three elements constituting the second stage planetary gear train 14b, the sun gear 31b is a fixed element and the ring gear 32b is an input element. The carrier 33b is an output element.

  9 to 11, among the three elements constituting the first stage planetary gear train 14a, the ring gear 32a is a fixed element, and the sun gear 31a is an input element. The carrier 33a is an output element. In the case shown in FIG. 9, among the three elements constituting the second stage planetary gear train 14b, the carrier 33b is a fixed element and the sun gear 31b is an input element. The ring gear 32b is an output element. On the other hand, in the case shown in FIG. 10, among the three elements constituting the second stage planetary gear train 14b, the ring gear 32b is a fixed element and the sun gear 31b is an input element. The carrier 33b is an output element. On the other hand, in the case shown in FIG. 11, among the three elements constituting the second stage planetary gear train 14b, the sun gear 31b is a fixed element and the ring gear 32b is an input element. The carrier 33b is an output element.

  In the case shown in FIGS. 12 to 14, the sun gear 31a is a fixed element and the ring gear 32a is an input element among the three elements constituting the first stage planetary gear train 14a. The carrier 33a is an output element. In order to use the ring gear 32 a as an input element, the ring gear 32 a is connected to the cylindrical portion 18 a of the rotating case 18. In the case shown in FIG. 12, among the three elements constituting the second stage planetary gear train 14b, the carrier 33b is a fixed element and the sun gear 31b is an input element. The ring gear 32b is an output element. On the other hand, in the case shown in FIG. 13, among the three elements constituting the second stage planetary gear train 14b, the ring gear 32b is a fixed element and the sun gear 31b is an input element. The carrier 33b is an output element. On the other hand, in the case shown in FIG. 14, among the three elements constituting the second stage planetary gear train 14 b, the sun gear 31 b is a fixed element, and the ring gear 32 b is an input element. The carrier 33b is an output element.

  FIG. 15 is a skeleton diagram showing an automobile drive device which is a modification of the fourth embodiment shown in FIG. In the case shown in FIG. 15, the first and second stage carriers 33a and 33b in FIG. 5 are both fixed to the support shaft 16, whereas the second stage carrier 33b is the first stage. It is fixed to the support shaft 16 via an eye carrier 33a. The embodiment shown in FIGS. 5 to 14 shows nine power transmission paths mainly constituted by combining planetary gear trains in two stages, and fixing means for the fixing elements are shown in FIGS. However, the fixing elements may be directly connected to each other as shown in FIG.

  FIG. 16 is a skeleton diagram showing an automobile drive device which is a modification of the eighth embodiment shown in FIG. In the case shown in FIG. 16, the first and second stage ring gears 32 a and 32 b in FIG. 10 are connected to the support shaft 16 fixed to the housing 12 so as to face the output shaft 15. Both ring gears 32 a and 32 b are loosely inserted outside the output shaft 15 and connected to a hollow support shaft 16 fixed to the housing 12. Further, in the case shown in FIG. 16, the carrier 33a as the first stage output element and the sun gear 31b as the second stage input element are connected by the shaft member, but in the case shown in FIG. The carrier 33a and the sun gear 31b are connected by a cylindrical member that covers the ring gears 32a and 32b. Thus, the connecting means for the output element of the first stage planetary gear train 14a and the input element of the second stage planetary gear train 14b is not limited to the embodiment shown in FIGS. Absent.

FIG. 17 is a table showing the relationship between the connection relationship between the components of the planetary gear mechanism and the gear ratio in the first to twelfth embodiments shown in FIGS. As shown in FIG. 17, a wide range of gear ratios can be realized depending on which element is a fixed element, an input element, and an output element. Where λ ₁ is the first gear ratio, λ ₂ is the second gear ratio, Z _S is the number of teeth of the sun gear, Z _R is the number of teeth of the ring gear, and the gear ratio λ is This is a value obtained by dividing Z _S by Z _R. A gear ratio with a negative value indicates that the rotation of the motor 13 is reversed and transmitted to the output shaft 15.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the speed reduction mechanism chamber 23 may incorporate a planetary gear train having more than two stages. A so-called double pinion type planetary gear mechanism can also be used as the speed reduction mechanism.

1 is a skeleton diagram showing a drive device for an electric vehicle according to a first embodiment of the present invention. It is a longitudinal cross-sectional view which shows the principal part of the drive device for electric vehicles shown in FIG. It is a skeleton figure which shows the drive device for electric vehicles which is the 2nd Embodiment in this invention. It is a skeleton figure which shows the drive device for electric vehicles which is the 3rd Embodiment of this invention. It is a skeleton figure which shows the drive device for electric vehicles which is the 4th Embodiment of this invention. It is a longitudinal cross-sectional view which shows the principal part of the drive device for electric vehicles shown in FIG. It is a skeleton figure which shows the drive device for electric vehicles which is the 5th Embodiment of this invention. It is a skeleton figure which shows the drive device for electric vehicles which is the 6th Embodiment of this invention. It is a skeleton figure which shows the drive device for electric vehicles which is the 7th Embodiment of this invention. It is a skeleton figure which shows the drive device for electric vehicles which is the 8th Embodiment of this invention. It is a skeleton figure which shows the drive device for electric vehicles which is the 9th Embodiment of this invention. It is a skeleton figure which shows the drive device for electric vehicles which is the 10th Embodiment of this invention. It is a skeleton figure which shows the drive device for electric vehicles which is the 11th Embodiment of this invention. It is a skeleton figure which shows the drive device for electric vehicles which is the 12th Embodiment of this invention. It is a skeleton figure which shows the drive device for motor vehicles which is a modification of 4th Embodiment shown by FIG. It is a skeleton figure which shows the drive device for motor vehicles which is a modification of 8th Embodiment shown by FIG. It is a table | surface which shows the relationship between the connection relation of the component of the planetary gear mechanism in 1st-12th embodiment shown by FIGS. 1-14, and a gear ratio.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Tire 11 Wheel 12 Housing 13 Electric motor 14 Planetary gear mechanism 14a, 14b Planetary gear train 15 Output shaft 16 Support shaft 18 Rotating case 21, 22 Bearing 23 Deceleration mechanism chamber 24 Motor accommodation chamber 25 Rotor 26 Stator 31, 31a, 31b Sun gear 32, 32a, 32b Ring gear 33, 33a, 33b Carrier

Claims (3)

A housing disposed in a wheel on which a tire is mounted and fixed to the vehicle body;
A rotating case that is rotatably mounted in the housing, has a cylindrical portion and end plate portions provided at both ends of the cylindrical portion, and forms a speed reduction mechanism chamber inside;
An electric motor comprising a stator attached to the inside of the housing and a rotor attached to the outside of the cylindrical portion;
A planetary gear including a sun gear, a ring gear, and a carrier, which constitutes an input element connected to the rotating case, an output element connected to the wheel, and a fixed element connected to the housing, and is incorporated in the speed reduction mechanism chamber And a mechanism for driving the electric vehicle.   2. The electric vehicle drive device according to claim 1, comprising a first sun gear, a first ring gear, and a first carrier, which are connected to the input element, the output element, and the housing connected to the rotating case. A first stage planetary gear train constituting a fixed element; a second sun gear; a second ring gear; and a second carrier, which are coupled to the output element of the first stage planetary gear train. The planetary gear mechanism is constituted by an input element that is connected to the wheel, an output element that is connected to the wheel, and a second-stage planetary gear train that forms a fixed element that is connected to the housing. apparatus. 3. The electric vehicle driving device according to claim 1, wherein a hollow shaft portion that supports a bearing between the end plate portion of the rotating case and the housing is provided on the end plate portion of the rotating case.

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