JP2005324708A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily adjust the tension of the belt wounded on a drive pulley and a driven pulley composing a power transmission mechanism of an electric motor with simple constitution in an electric power steering device. <P>SOLUTION: In the electric power steering device 10, the drive pulley 22 is supported by a gear housing 11 through an adjustment collar 50. The adjustment collar 50 is equipped with a outer peripheral support part 51 supported gear housing and the inner peripheral support part 52 supporting the drive pulley 22. The support center of the inner peripheral support part 52 is eccentrically disposed relative to the support center of the outer peripheral support part 51. The mounting angle position around the support center of the outer peripheral support part 51 of the adjustment collar 50 relative to the gear housing 11 is adjustably supported, and a plurality of bolt mounting holes 55A to 55C corresponding to every plurality of mounting angle positions are provided on either the adjustment collar 50 or the gear housing 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electric power steering apparatus.

The electric power steering device described in Patent Document 1 supports a rack shaft on a gear housing so as to be linearly movable, and an electric motor is attached to the gear housing, and the rotational force of a driving pulley coupled to the rotating shaft of the electric motor is The power is transmitted to the rack shaft through a power transmission mechanism including a driven pulley connected to the driving pulley via a belt. An electric motor assists the steering force that the driver steers the steering wheel and moves the rack shaft with which the pinion connected to the steering shaft engages.
62-145777

In Patent Document 1, there is a possibility that the belt wound around the drive pulley and the driven pulley may loosen and eventually come off, making it difficult to properly assist the steering force by the electric motor.
An object of the present invention is to make it possible to easily adjust the tension of a belt wound around a drive pulley and a driven pulley constituting a power transmission mechanism of an electric motor with a simple configuration in an electric power steering device.

  Another object of the present invention is to make it possible to easily adjust the backlash between the tooth surfaces of the drive gear and the driven gear constituting the power transmission mechanism of the electric motor with a simple configuration in the electric power steering apparatus. is there.

  According to the first aspect of the present invention, the rack shaft is supported on the gear housing so as to be linearly movable, an electric motor is attached to the gear housing, and the rotational force of the driving pulley coupled to the rotating shaft of the electric motor is applied to the belt on the driving pulley. In an electric power steering apparatus for transmitting to a rack shaft via a power transmission mechanism including a driven pulley connected via a drive pulley is supported by a gear housing via an adjustment collar, and the adjustment collar is supported by the gear housing. And an inner peripheral support portion that supports the drive pulley, the support center of the inner peripheral support portion is eccentrically arranged with respect to the support center of the outer peripheral support portion, and the support center of the outer peripheral support portion of the adjustment collar with respect to the gear housing Supports adjustable mounting angle positions around and provides an adjustment collar that can be mounted at one of multiple mounting angle positions. Upon bolt fastening to the housing, it is provided with a plurality of bolt mounting holes corresponding to the respective mounting angle position on one of the adjusting collar and the gear housing.

  According to the second aspect of the present invention, the rack shaft is supported on the gear housing so as to be linearly movable, and an electric motor is attached to the gear housing, and the rotational force of the driving gear coupled to the rotating shaft of the electric motor meshes with the driving gear. In an electric power steering apparatus for transmitting to a rack shaft through a power transmission mechanism including a driven gear, a drive gear is supported by a gear housing via an adjustment collar, the adjustment collar is supported by an outer peripheral support portion supported by the gear housing, and a drive gear An inner peripheral support portion that supports the outer peripheral support portion, the support center of the inner peripheral support portion is eccentrically arranged with respect to the support center of the outer peripheral support portion, and the mounting angle position of the adjustment collar relative to the gear housing around the support center of the outer peripheral support portion The adjustment collar that can be mounted at any of a plurality of mounting angle positions is bolted to the gear housing. Runisaishi, in which a plurality of bolt mounting holes corresponding to the respective mounting angle position provided on one of the adjusting collar and the gear housing.

(Claim 1)
(a) The support center O1 of the outer periphery support portion supported by the gear housing of the adjustment collar and the support center O2 of the inner periphery support portion supporting the drive pulley of the adjustment collar are eccentrically arranged with an eccentricity e. . Accordingly, when the mounting angle position of the adjusting collar with respect to the gear housing is adjusted, the center axis position of the drive pulley with respect to the gear housing is displaced due to the presence of the eccentricity e. As a result, the distance between the axes of the drive pulley relative to the driven pulley on which the support shaft O3 with respect to the gear housing is fixed is changed. Thereby, the tension of the belt wound around the driving pulley and the driven pulley can be set appropriately, the belt can be prevented from loosening and eventually coming off, and the steering assist by the electric motor can be stabilized.

  (b) The adjustment collar attached to any one of the plurality of attachment angle positions is fastened to the gear housing by a bolt using a bolt attachment hole (bolt insertion hole or screw hole) corresponding to the attachment angle position. Since bolt mounting holes are prepared for each mounting angle position, the bolt insertion holes can be rounded without using the long bolt insertion holes, and the adjustment collar mounting angle positions can be inserted through the long hole bolts. It can prevent shifting along the hole.

(Claim 2)
(c) The support center O1 of the outer periphery support portion supported by the gear housing of the adjustment collar and the support center O2 of the inner periphery support portion supporting the drive gear of the adjustment collar are arranged eccentrically with an eccentricity e. . Therefore, when the mounting angle position of the adjusting collar with respect to the gear housing is adjusted, the center axis position of the drive gear with respect to the gear housing is displaced due to the presence of the eccentricity e. As a result, the distance between the shafts of the drive gear with respect to the driven gear to which the support shaft O3 with respect to the gear housing is fixed is changed. As a result, it is possible to easily adjust the backlash between the drive gear and the driven gear, set the engagement between the drive gear and the driven gear appropriately, and stabilize the steering assist by the electric motor.

  (d) The adjustment collar attached to any one of the plurality of attachment angle positions is fastened to the gear housing by a bolt using a bolt attachment hole (bolt insertion hole or screw hole) corresponding to the attachment angle position. Since bolt mounting holes are prepared for each mounting angle position, the bolt insertion holes can be rounded without using the long bolt insertion holes, and the adjustment collar mounting angle positions can be inserted through the long hole bolts. It can prevent shifting along the hole.

  1 is an overall side view showing an electric power steering apparatus according to a first embodiment, FIG. 2 is an enlarged view of main parts of FIG. 1, FIG. 3 is a cross-sectional view of main parts of FIG. 1, and FIG. FIG. 5 is an end view showing the adjustment collar, FIG. 6 is a cross-sectional view of the main part showing the electric power steering apparatus of the second embodiment, and FIG. 7 is a schematic arrow view taken along line VII-VII in FIG.

Example 1 (FIGS. 1 to 5)
As shown in FIG. 1, the electric power steering apparatus 10 according to the first embodiment includes a gear housing 11 (first gear housing 11A and second gear housing 11B), and the gear housing 11 (first gear housing 11A) is steered. An input shaft 12 is supported, an output shaft (not shown) is connected to the input shaft 12 via a torsion bar 13, a pinion (not shown) is provided on the output shaft, and a rack shaft 14 meshing with the pinion is connected to a gear housing. 11 is supported so as to be linearly movable in the left-right direction. A steering torque sensor (not shown) is provided between the input shaft 12 and the output shaft. The steering torque sensor detects the steering torque based on the relative rotational displacement generated between the input shaft 12 and the output shaft due to elastic torsional deformation of the torsion bar caused by the steering torque applied to the steering wheel.

  The electric power steering apparatus 10 has both end portions of the rack shaft 14 projecting from both sides of the gear housing 11 (first gear housing 11A, second gear housing 11B), and tie rods 15A, 15B are connected to the end portions of the rack shaft 14, The left and right wheels can be steered via tie rods 15A and 15B that are linked to the 14 linear movements.

  As shown in FIG. 2, the electric power steering apparatus 10 has the electric motor 20 attached to the gear housing 11 (second gear housing 11B) with a mounting bolt 21. As shown in FIG. 3, the serration hole of the rotary shaft 20A of the electric motor 20 is provided. The serration of the central shaft 23 of the drive pulley 22 is coaxially coupled. The center shaft 23 of the drive pulley 22 is supported by the gear housing 11 (the first gear housing 11A and the second gear housing 11B) as described later.

  The electric power steering apparatus 10 is provided with a ball screw 30 on the rack shaft 14, a ball nut 32 that meshes with the ball screw 30 via a ball 31, and a bearing 33 supported by the gear housing 11 (first gear housing 11 </ b> A). Thus, the ball nut 32 is rotatably supported. Reference numeral 33 </ b> A denotes an outer ring nut of the bearing 33.

  A spline hole provided in a boss portion of the driven pulley 36 is fixed to the spline portion on the outer periphery of the ball nut 32 by spline connection. The boss portion of the driven pulley 36 protrudes from the end face of the ball nut 32 and is rotatably supported by a bearing 34 supported by the gear housing 11 (second gear housing 11B). Reference numeral 34 </ b> A is an outer ring nut of the bearing 34. The first gear housing 11A and the second housing 11B are fastened by bolts 16.

  The electric power steering apparatus 10 wraps a belt 37 around a drive pulley 22 on the electric motor 20 side and a driven pulley 36 on the ball nut 32 side, and rotates the rotational force of the drive pulley 22 from the belt 37 via the driven pulley 36. This is transmitted to the nut 32, and consequently to the rack shaft 14, and the rack shaft 14 is linearly moved.

Hereinafter, the operation of the electric power steering apparatus 10 will be described.
(1) When the steering torque detected by the steering torque sensor is lower than a predetermined value, the steering assist force is unnecessary and the electric motor 20 is not driven.

  (2) Since the steering assist force is required when the steering torque detected by the steering torque sensor exceeds a predetermined value, the electric motor 20 is driven. The rotational force of the drive pulley 22 based on the torque generated by the electric motor 20 is transmitted from the belt 37 to the ball nut 32 via the driven pulley 36, and becomes a steering assist force that linearly moves the rack shaft 14 via the ball screw 30.

  The electric power steering apparatus 10 has a tension adjustment structure of a belt 37 wound around the drive pulley 22 and the driven pulley 36 as follows (FIGS. 2 to 5).

  The drive pulley 22 is supported by the gear housing 11 (the first gear housing 11A and the second gear housing 11B) via the adjustment collar 50. That is, a central shaft 23 that is press-fitted into the central hole and fixed to the drive pulley 22 is coaxially and integrally coupled. The central shaft 23 is pivotally supported in a both-end supported state through bearings 41 and 42 such as ball bearings fitted and supported in the small diameter hole 52A and the large diameter hole 52B of the circular inner periphery support portion 52 of the adjustment collar 50. The bearing 42 is fixed to the adjustment collar 50 by an outer ring nut 43 screwed to the adjustment collar 50. The adjustment collar 50 includes a small-diameter support hole 17A provided in the first gear housing 11A and a large-diameter support hole 17B provided in the second gear housing 11B, respectively. Is supported by fitting.

  The adjustment collar 50 has an outer periphery on a small-diameter support hole 17A that is open on a mounting surface for the second gear housing 11B in the first gear housing 11A and a large-diameter support hole 17B that is formed through the second gear housing 11B. As will be described later, a second portion 51A and a large-diameter portion 51B of the support portion 51 are fitted to each other and a mounting flange 53 is abutted against the mounting surface for the adjustment collar 50 in the second gear housing 11B. It is screwed and attached to the gear housing 11B.

  The electric motor 20 is attached to the attachment flange 53 of the adjustment collar 50 by the attachment bolt 21 and is attached to the second gear housing 11B via the adjustment collar 50. However, the mounting bolt 21 of the electric motor 20 may be directly screwed and attached to the second gear housing 11B through a bolt insertion hole provided in the mounting flange 53 of the adjustment collar 50.

  As described above, the adjustment collar 50 includes the outer peripheral support portions 51 (51A, 51B) supported by the gear housing 11 and the inner peripheral support portions 52 (52A, 52B) that support the drive pulley 22. FIG. As shown in FIG. 5, the support center O2 of the inner peripheral support portion 52 is eccentrically arranged by the eccentric amount e with respect to the support center O1 of the outer peripheral support portion 51. The adjustment collar 50 can adjust the mounting angle position of the adjustment collar 50 around the support center O1 of the outer peripheral support portion 51 of the adjustment collar 50 with respect to the gear housing 11 by a rotational operation force applied to the flange 53. When the mounting angle position of the adjustment collar 50 is adjusted, the center axis position of the drive pulley 22 with respect to the gear housing 11 is displaced due to the presence of the eccentricity e, and the distance between the axes of the drive pulley 22 with respect to the driven pulley 36 is changed. .

  However, in the electric power steering apparatus 10, the mounting angle position of the adjustment collar 50 with respect to the gear housing 11 can be fixed in a state where there is no possibility of shifting at a plurality of positions, in this embodiment, three positions. For this reason, the adjustment collar 50 is provided with two round hole bolt mounting holes 55A, 55B, and 55C on three diameters passing through the support center O1 of the outer peripheral support portion 51 on the flange 53. The bolt mounting holes 55 </ b> A to 55 </ b> C are provided so as to correspond to each of the three mounting angle positions of the adjustment collar 50, and serve as bolt insertion holes for the bolts 54. Accordingly, when the bolt 54 is inserted into one of the mounting holes selected from the bolt mounting holes 55A to 55C of the flange 53 and is fastened to only one screw hole 56 provided in the second gear housing 11B, the adjustment is performed. The collar 50 is set to one of three attachment angle positions.

  The distance between the axes of the driving pulley 22 and the driven pulley 36 when the mounting angle position of the adjustment collar 50 is set by the bolt mounting hole 55A is increased by, for example, 1 mm from the reference distance, and the driving pulley when the adjusting collar 50 is set by the bolt mounting hole 55B. The distance between the axes of the pulley 22 and the driven pulley 36 is increased by, for example, 2 mm with respect to the reference distance, and the distance between the axes of the drive pulley 22 and the driven pulley 36 when set by the bolt mounting hole 55C is increased by, for example, 3 mm with respect to the reference distance. The

According to the present embodiment, the following operational effects can be obtained.
(a) An eccentricity e between the support center O1 of the outer peripheral support portion 51 supported by the gear housing 11 of the adjustment collar 50 and the support center O2 of the inner peripheral support portion 52 supporting the drive pulley 22 of the adjustment collar 50. It is arranged eccentrically. Therefore, when the mounting angle position of the adjustment collar 50 with respect to the gear housing 11 is adjusted, the center axis position of the drive pulley 22 with respect to the gear housing 11 is displaced due to the presence of the eccentricity e. As a result, the distance between the axes of the drive pulley 22 with respect to the driven pulley 36 on which the support shaft O3 with respect to the gear housing 11 is fixed is changed. As a result, the tension of the belt 37 wound around the drive pulley 22 and the driven pulley 36 can be set appropriately, the belt 37 can be prevented from loosening and eventually coming off, and the steering assist by the electric motor 20 can be stabilized.

  (b) The adjustment collar 50 attached to any one of a plurality of attachment angle positions is provided with a gear housing by bolts 54 using bolt attachment holes 55A, 55B, 55C (bolt insertion holes or screw holes) corresponding to the attachment angle positions. 11. Since the bolt mounting holes 55A, 55B, and 55C are prepared for each mounting angle position, the bolt insertion hole can be formed into a round hole without using the long hole-shaped bolt insertion hole, and the mounting angle position of the adjustment collar 50 can be adjusted. It can prevent shifting | deviating along a long hole-shaped bolt insertion hole.

Example 2 (FIGS. 6 and 7)
The electric power steering device 10 of the second embodiment is different from the electric power steering device 10 of the first embodiment in that the drive gear 61 is provided in the serration hole of the rotating shaft 20A of the electric motor 20 as shown in FIGS. The serrations of the central shaft 62 are coaxially coupled, and the driven gear 63 is spline-coupled with the outer periphery of the ball nut 32 so that the drive gear 61 and the driven gear 63 are engaged. The rotational force of the drive gear 61 is transmitted to the ball nut 32 via the driven gear 63 and eventually transmitted to the rack shaft 14 to linearly move the rack shaft 14.

  The electric power steering apparatus 10 has a backlash adjustment structure between the tooth surfaces of the drive gear 61 and the driven gear 63 as follows (FIGS. 6 and 7).

  The drive gear 61 is supported by the gear housing 11 (the first gear housing 11A and the second gear housing 11B) via the adjustment collar 50. That is, a central shaft 62 that is press-fitted into the center hole and fixed to the drive gear 61 is coaxially and integrally coupled. The center shaft 62 is pivotally supported in a both-end supported state through bearings 41 and 42 such as ball bearings fitted and supported in the small diameter hole 52A and the large diameter hole 52B of the circular inner periphery support portion 52 of the adjustment collar 50. The bearing 42 is fixed to the adjustment collar 50 by an outer ring nut 43 screwed to the adjustment collar 50. The adjustment collar 50 includes a small-diameter support hole 17A provided in the first gear housing 11A and a large-diameter support hole 17B provided in the second gear housing 11B, respectively. Is supported by fitting.

  The adjustment collar 50 has an outer periphery on a small-diameter support hole 17A that is open on a mounting surface for the second gear housing 11B in the first gear housing 11A and a large-diameter support hole 17B that is formed through the second gear housing 11B. As will be described later, a second portion 51A and a large-diameter portion 51B of the support portion 51 are fitted to each other and a mounting flange 53 is abutted against the mounting surface for the adjustment collar 50 in the second gear housing 11B. It is screwed and attached to the gear housing 11B.

  The electric motor 20 is attached to the attachment flange 53 of the adjustment collar 50 by the attachment bolt 21 and is attached to the second gear housing 11B via the adjustment collar 50. However, the mounting bolt 21 of the electric motor 20 may be directly screwed and attached to the second gear housing 11B through a bolt insertion hole provided in the mounting flange 53 of the adjustment collar 50.

  As described above, the adjustment collar 50 includes the outer peripheral support portions 51 (51A and 51B) supported by the gear housing 11 and the inner peripheral support portions 52 (52A and 52B) that support the drive gear 61. FIG. As shown in FIG. 5, the support center O2 of the inner peripheral support portion 52 is eccentrically arranged by the eccentric amount e with respect to the support center O1 of the outer peripheral support portion 51. The adjustment collar 50 can adjust the mounting angle position of the adjustment collar 50 around the support center O1 of the outer peripheral support portion 51 of the adjustment collar 50 with respect to the gear housing 11 by a rotational operation force applied to the flange 53. When the mounting angle position of the adjustment collar 50 is adjusted, the center axis position of the drive gear 61 relative to the gear housing 11 is displaced due to the presence of the eccentricity e, and the distance between the axes of the drive gear 61 relative to the driven gear 63 is changed. .

  However, in the electric power steering apparatus 10, the mounting angle position of the adjustment collar 50 with respect to the gear housing 11 can be fixed in a state where there is no possibility of shifting at a plurality of positions, in this embodiment, three positions. For this reason, the adjustment collar 50 is provided with two round hole bolt mounting holes 55A, 55B, and 55C on three diameters passing through the support center O1 of the outer peripheral support portion 51 on the flange 53. The bolt mounting holes 55 </ b> A to 55 </ b> C are provided so as to correspond to each of the three mounting angle positions of the adjustment collar 50, and serve as bolt insertion holes for the bolts 54. Accordingly, when the bolt 54 is inserted into one of the mounting holes selected from the bolt mounting holes 55A to 55C of the flange 53 and is fastened to only one screw hole 56 provided in the second gear housing 11B, the adjustment is performed. The collar 50 is set to one of three attachment angle positions.

  The distance between the shafts of the drive gear 61 and the driven gear 63 when the mounting angle position of the adjustment collar 50 is set by the bolt mounting hole 55A is increased by, for example, 1 mm from the reference distance, and the driving gear when the adjustment collar 50 is set by the bolt mounting hole 55B. The distance between the shaft 61 and the driven gear 63 is increased by, for example, 2 mm from the reference distance, and the distance between the drive gear 61 and the driven gear 63 when set by the bolt mounting hole 55C is increased by, for example, 3 mm from the reference distance. The

According to the present embodiment, the following operational effects can be obtained.
(a) An eccentricity e between the support center O1 of the outer peripheral support portion 51 supported by the gear housing 11 of the adjustment collar 50 and the support center O2 of the inner peripheral support portion 52 supporting the drive gear 61 of the adjustment collar 50. It is arranged eccentrically. Therefore, when the mounting angle position of the adjustment collar 50 with respect to the gear housing 11 is adjusted, the center axis position of the drive gear 61 with respect to the gear housing 11 is displaced due to the presence of the eccentricity e. As a result, the distance between the axes of the drive gear 61 with respect to the driven gear 63 to which the support shaft O3 with respect to the gear housing 11 is fixed is changed. As a result, the backlash between the drive gear 61 and the driven gear 63 can be easily adjusted, the meshing between the drive gear 61 and the driven gear 63 can be set appropriately, and the steering assist by the electric motor 20 can be stabilized. .

  (b) The adjustment collar 50 attached to any one of the plurality of attachment angle positions has a gear housing 11 formed by bolts using bolt attachment holes 55A, 55B, 55C (bolt insertion holes or screw holes) corresponding to the attachment angle positions. To be concluded. Since the bolt mounting holes 55A, 55B, and 55C are prepared for each mounting angle position, the bolt insertion hole can be formed into a round hole without using the long hole-shaped bolt insertion hole, and the mounting angle position of the adjustment collar 50 can be adjusted. It can prevent shifting | deviating along a long hole-shaped bolt insertion hole.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention. For example, the plurality of bolt mounting holes may be provided in at least one of the adjustment collar and the gear housing. The plurality of bolt mounting holes are not limited to bolt insertion holes, and may be screw holes. In this case, screw holes as a plurality of bolt mounting holes are provided on one of the adjustment collar and the gear housing. At least one round hole bolt insertion hole is provided on the other side.

FIG. 1 is an overall side view showing an electric power steering apparatus according to a first embodiment. FIG. 2 is an enlarged view of a main part of FIG. 3 is a cross-sectional view of the main part of FIG. FIG. 4 is a schematic arrow view of FIG. FIG. 5 is an end view showing the adjustment collar. FIG. 6 is a cross-sectional view of an essential part showing the electric power steering apparatus of the second embodiment. FIG. 7 is a schematic arrow view taken along line VII-VII in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electric power steering apparatus 11 Gear housing 14 Rack shaft 20 Electric motor 20A Rotating shaft 22 Drive pulley 36 Driven pulley 37 Belt 50 Adjustment collar 51 Outer periphery support part 52 Inner periphery support part 53 Flange 54 Bolt 55A, 55B, 55C Bolt attachment hole 61 Drive gear 63 Driven gear

Claims (2)

A rack shaft is supported on the gear housing so as to be linearly movable, and an electric motor is attached to the gear housing, and the driving pulley coupled to the rotating shaft of the electric motor is connected to the driving pulley via a belt. In an electric power steering device that transmits to a rack shaft via a power transmission mechanism including
The drive pulley is supported on the gear housing via the adjustment collar,
The adjustment collar includes an outer periphery support portion supported by the gear housing and an inner periphery support portion that supports the drive pulley, and the support center of the inner periphery support portion is eccentrically arranged with respect to the support center of the outer periphery support portion. The mounting angle position around the support center of the outer peripheral support portion of the adjustment collar with respect to the support is adjustable,
When bolting an adjustment collar that can be mounted at any of a plurality of mounting angle positions to the gear housing, a plurality of bolt mounting holes corresponding to each mounting angle position are provided in one of the adjustment collar and the gear housing. Electric power steering device. A power transmission mechanism including a driven gear that supports a rack shaft so as to be linearly movable on the gear housing, an electric motor is mounted on the gear housing, and the rotational force of the driving gear coupled to the rotating shaft of the electric motor meshes with the driving gear. In the electric power steering device that transmits to the rack shaft via
The drive gear is supported on the gear housing via the adjustment collar,
The adjustment collar includes an outer periphery support portion supported by the gear housing and an inner periphery support portion that supports the drive gear, and the support center of the inner periphery support portion is eccentrically arranged with respect to the support center of the outer periphery support portion, and the gear housing The mounting angle position around the support center of the outer peripheral support portion of the adjustment collar with respect to the support is adjustable,
When bolting an adjustment collar that can be mounted at any of a plurality of mounting angle positions to the gear housing, a plurality of bolt mounting holes corresponding to each mounting angle position are provided in one of the adjustment collar and the gear housing. Electric power steering device.

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