JP7355544B2 - geared motor - Google Patents

Description

The present invention relates to a geared motor.

In recent years, as electronic devices such as smartphones have become more sophisticated, the development of thinner, higher-output geared motors is progressing. For example, Patent Document 1 discloses a gearbox device for mobile electronic devices that includes a slide mechanism.

JP 2019-47589 Publication

As the output of geared motors continues to increase, there is a need to further increase the power transmission efficiency of each gear mounted on the geared motor.

In view of the above problems, one aspect of the present invention aims to provide a geared motor with improved gear transmission efficiency.

One aspect of the geared motor of the present invention includes a drive unit having a motor part extending along the motor axis, a drive shaft rotating around the motor axis on one axial side of the motor part, and a slide axis parallel to the motor axis. a slide mechanism having a lead screw that is rotatable as a center and a slide nut inserted into the lead screw; a gear train that transmits power from the drive shaft to the lead screw; the drive unit, the slide mechanism, and the gear train. A frame supporting the. The frame includes a first support portion that rotatably supports one end of the drive shaft and the lead screw in the axial direction. The gear train includes a drive gear fixed to the drive shaft that extends to one side in the axial direction with respect to the first support part, and a drive gear fixed to the lead screw that extends to one side in the axial direction with respect to the first support part. and an intermediate gear that meshes with the drive gear and the counter gear. An intermediate shaft centered on an intermediate axis parallel to the motor axis is provided on a surface of the first support part facing one side in the axial direction. The intermediate gear is rotatably supported by the intermediate shaft.

According to one aspect of the present invention, a geared motor with improved gear transmission efficiency is provided.

FIG. 1 is a partially exploded perspective view of a geared motor according to an embodiment. FIG. 2 is a cross-sectional view of a geared motor according to one embodiment. FIG. 3 is a front view of a modified geared motor.

Hereinafter, a geared motor according to an embodiment of the present invention will be described with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiments, and can be arbitrarily modified within the scope of the technical idea of the present invention.

In the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the following explanation, unless otherwise specified, the direction parallel to the motor axis J1 (Z-axis direction) is simply referred to as the "axial direction," the -Z side is simply referred to as one axial side, and the +Z side is simply referred to as the axial direction. Call it the other side.

FIG. 1 is a partially exploded perspective view of a geared motor 1. As shown in FIG. FIG. 2 is a sectional view of the geared motor 1. The geared motor 1 of this embodiment is mounted on a thin electronic device whose dimension along the Y-axis direction is suppressed.
As shown in FIG. 2, the geared motor 1 includes a drive unit 2, a slide mechanism 5, a gear train 4, a frame 10, and a lid member 19.

The gear train 4 includes a drive gear 41, an intermediate gear 42, and a counter gear 43. Drive unit 2 and drive gear 41 are arranged along motor axis J1. Intermediate gear 42 is arranged along intermediate axis J2. The slide mechanism 5 and the counter gear 43 are arranged along the slide axis J3.

The motor axis J1, the intermediate axis J2, and the slide axis J3 extend parallel to each other along the Z-axis direction. That is, the intermediate axis J2 and the slide axis J3 are parallel to the motor axis J1. The motor axis J1, the intermediate axis J2, and the slide axis J3 are lined up in a straight line in the X-axis direction when viewed from the axial direction.
Each part of the geared motor 1 will be described in detail below.

<Drive unit>
The drive unit 2 includes a motor section 20, a planetary gear mechanism 32, and a drive shaft 30.

The motor section 20 extends along the motor axis J1. The motor unit 20 includes a plurality of (two in this embodiment) motors 21 stacked in the axial direction. In this embodiment, the motor 21 is a stepping motor. The motor 21 includes a rotor 21a that rotates around a motor axis J1, and a stator 21b that surrounds the rotor 21a from the outside in the radial direction of the motor axis J1.

The rotors 21a of the plurality of motors 21 are connected in the axial direction to form a single connected rotor 21c. The connected rotor 21c has a motor shaft 21d that extends in the axial direction about the motor axis J1. On the other hand, the stators 21b of the plurality of motors 21 are stacked in the axial direction and are coupled to each other by coupling means such as welding.

According to this embodiment, since the motor section 20 includes the plurality of motors 21 stacked in the axial direction, the power of the plurality of motors 21 can be combined and output from the connected rotor 21c. Moreover, since the plurality of motors 21 are arranged in the axial direction, it is possible to increase the output of the motor section 20 while suppressing the motor section 20 from increasing in size in the radial direction of the motor axis J1, and the electronic equipment in which the geared motor 1 is mounted can be suppressed. can be made thinner.

The planetary gear mechanism 32 is connected to the motor section 20. The planetary gear mechanism 32 decelerates the power output from the motor section 20.

The planetary gear mechanism 32 includes a first sun gear 33a, three first planet gears 33b, a first carrier 33c, a second sun gear 34a, three second planet gears 34b, and a second carrier 34c. It has an internal gear 35.

The internal gear 35 has a cylindrical shape that extends in the axial direction centering on the motor axis J1. The internal gear 35 is a gear provided on the inner peripheral surface and meshes with the first planetary gear 33b and the second planetary gear 34b. Internal gear 35 is fixed to frame 10 and does not rotate.

The first sun gear 33a is fixed to the motor shaft 21d. The first sun gear 33a rotates about the motor axis J1 together with the motor shaft 21d.

The three first planetary gears 33b are arranged at equal intervals in the circumferential direction of the motor axis J1. The three first planetary gears 33b mesh with the first sun gear 33a. The three first planetary gears 33b revolve in the circumferential direction of the motor axis J1 as the first sun gear 33a rotates.

The first carrier 33c includes a disk portion, three sub-shafts that extend from the disk portion to one side in the axial direction and rotatably support the first planetary gear 33b, and a main shaft that extends from the disk portion to the other side in the axial direction. , has. The first carrier 33c rotates around the motor axis J1 as the three first planetary gears 33b revolve around the motor axis J1.

The second sun gear 34a is provided on the outer peripheral surface of the main shaft of the first carrier 33c. The second sun gear 34a rotates about the motor axis J1 together with the first carrier 33c.

The three second planetary gears 34b are arranged at equal intervals in the circumferential direction of the motor axis J1. The three second planetary gears 34b mesh with the second sun gear 34a. The three second planetary gears 34b revolve in the circumferential direction of the motor axis J1 as the second sun gear 34a rotates.

The second carrier 34c includes a disk portion, three subshafts that extend from the disk portion to one side in the axial direction and rotatably support the second planetary gear 34b, and a main shaft that extends from the disk portion to the other side in the axial direction. , has. The second carrier 34c rotates around the motor axis J1 as the three second planetary gears 34b revolve around the motor axis J1. The main shaft of the second carrier 34c is rotatably supported by a sliding bearing 35a attached to the other end of the internal gear 35 in the axial direction. A holding hole 34d is provided on the other end surface of the second carrier 34c in the axial direction.

The drive shaft 30 is inserted into the holding hole 34d. The drive shaft 30 extends from the planetary gear mechanism 32 to one side in the axial direction. The drive shaft 30 rotates around the motor axis J1 together with the second carrier 34c on one axial side of the motor section 20. Further, the end of the drive shaft 30 on one axial side is rotatably supported by the lid member 19.

The drive unit 2 of this embodiment includes a planetary gear mechanism 32 located on one side of the motor section 20 in the axial direction and rotating around the motor axis J1. Therefore, in the process of transmitting the power of the motor 21, the drive unit 2 decelerates the power and outputs it from the drive shaft 30. Furthermore, the planetary gear mechanism 32 of this embodiment has two types of sun gears and planetary gears, and is decelerated in two stages. Therefore, according to the drive unit 2 of this embodiment, a large reduction ratio can be achieved.

<Slide mechanism>
The slide mechanism 5 includes a lead screw 51 and a guide shaft 52 that extend in the axial direction, and a slide nut 53 that is inserted into the lead screw 51 and the guide shaft 52.

Lead screw 51 extends along slide axis J3. A male thread is provided on the outer peripheral surface of the lead screw 51. The lead screw 51 rotates around the slide axis J3 by the power of the drive unit 2 transmitted through the gear train 4.

Guide shaft 52 extends parallel to lead screw 51. That is, the guide shaft 52 extends in the axial direction of the slide axis J3. The guide shaft 52 is located on the -X side with respect to the lead screw 51. Both ends of the guide shaft 52 are fixed to the frame 10, respectively. That is, the guide shaft 52 is supported by the frame 10.

The slide nut 53 has a nut hole 53n into which the lead screw 51 is inserted, and a slide hole 53s into which the guide shaft 52 is inserted. A female thread into which the male thread of the lead screw 51 fits is provided on the inner peripheral surface of the nut hole 53n. The outer circumferential surface of the guide shaft 52 contacts the inner circumferential surface of the slide hole 53s.

Further, the slide nut 53 includes a base portion 53a and a sliding portion 53b embedded within the base portion 53a. The sliding portion 53b is made of a low friction material. The sliding portion 53b constitutes the inner peripheral surface of the nut hole 53n and the slide hole 53s. The slide nut 53 is guided by the guide shaft 52 and moves in the axial direction as the guide shaft 52 rotates around the slide axis J3.

<Gear train>
Gear train 4 transmits power from drive shaft 30 to lead screw 51. The gear train 4 includes a drive gear 41, an intermediate gear 42, and a counter gear 43. Drive gear 41, intermediate gear 42, and counter gear 43 are arranged in this order along the X-axis direction to transmit power. In this embodiment, the number of teeth of the drive gear 41 and the number of teeth of the counter gear 43 are the same. Therefore, the gear train 4 of this embodiment does not perform deceleration or speed increase.

Drive gear 41 is fixed to drive shaft 30. Drive gear 41 rotates around motor axis J1 together with drive shaft 30.

Counter gear 43 is fixed to lead screw 51. The drive gear 41 rotates together with the lead screw 51 around the slide axis J3.

The intermediate gear 42 is rotatably supported by an intermediate shaft 11a extending from the frame 10 to one side in the axial direction. The intermediate shaft 11a extends along the intermediate axis J2. Therefore, the intermediate gear 42 rotates around the intermediate axis J2. Intermediate gear 42 is arranged between drive gear 41 and counter gear 43. The intermediate gear 42 meshes with the drive gear 41 and the counter gear 43 and transmits power from the drive gear 41 to the counter gear 43.

<Frame>
The frame 10 is configured in a frame shape. The frame 10 is molded, for example, by metal injection molding (MIM). Frame 10 supports drive unit 2, slide mechanism 5, and gear train 4.

The frame 10 includes a plurality of first support parts 11 and second support parts 12 extending along the X-axis direction, first beam parts 15 and second beam parts 16 extending along the Z-axis direction, and 3) fixing parts 13.

The first support portion 11 supports one end of the drive unit 2 and the slide mechanism 5 in the axial direction. An internal gear 35 of a planetary gear mechanism 32 is fixed to the surface of the first support portion 11 facing the other axial side. As described above, the internal gear 35 rotatably supports the second carrier 34c via the sliding bearing 35a. Further, the drive shaft 30 is fixed to the second carrier 34c. That is, the first support portion 11 rotatably supports the drive shaft 30 via the internal gear 35, the sliding bearing 35a, and the second carrier 34c. Further, a drive gear 41 is fixed to the drive shaft 30 at a portion extending toward one side in the axial direction with respect to the first support portion 11 .

The first support portion 11 is provided with a first holding hole 11j and a second holding hole 11k that penetrate in the axial direction and are lined up in the X-axis direction.

The first holding hole 11j extends along the slide axis J3. A sliding bearing 11c is press-fitted into the first holding hole 11j. Thereby, the sliding bearing 11c is fixed to the first support portion 11. A lead screw 51 is inserted into the sliding bearing 11c. The sliding bearing 11c rotatably supports one end of the lead screw 51 in the axial direction. That is, the first support portion 11 rotatably supports one end of the lead screw 51 in the axial direction via the sliding bearing 11c. Further, a counter gear 43 is fixed to one end of the lead screw 51 in the axial direction at a portion extending toward the one axial side with respect to the first support portion 11 .

The other end of the guide shaft 52 in the axial direction is press-fitted into the second holding hole 11k. Thereby, the other end of the guide shaft 52 in the axial direction is fixed to the frame 10. Further, the first support portion 11 supports the other end of the guide shaft 52 in the axial direction.

An intermediate shaft 11a extending toward the one axial side is provided on a surface of the first support portion 11 facing one axial side. The intermediate shaft 11a extends in the axial direction centering on the intermediate axis J2. As described above, the intermediate shaft 11a rotatably supports the intermediate gear 42.

According to this embodiment, each gear (drive gear 41, intermediate gear 42, and counter gear 43) constituting the gear train 4 is connected to a shaft (drive shaft 30, intermediate shaft 11a, and lead screw) that extends to one side in the axial direction. 51). Therefore, each gear can be assembled from one direction during the assembly process, and the assembly process can be simplified. In addition, since each shaft (drive shaft 30, intermediate shaft 11a, and lead screw 51) is all positioned by the frame 10, the distance between the axes of each shaft can be maintained with high precision, and the power transmission efficiency of the gear train 4 can be improved. can be increased.

According to this embodiment, the motor axis J1, the intermediate axis J2, and the slide axis J3 are lined up in a straight line when viewed from the axial direction. That is, the gears of the gear train 4 are arranged side by side in one direction. Therefore, it is possible to provide a geared motor 1 whose size in the Y-axis direction is reduced. That is, according to the present embodiment, it is possible to provide a geared motor 1 that can be installed in a thin device such as a smartphone. In this embodiment, not only the motor axis J1, the intermediate axis J2, and the slide axis J3, but also the axis of the guide shaft 52 are arranged in a straight line when viewed from the axial direction. Therefore, according to the present embodiment, the guide shaft 52 can increase the stability of the sliding movement of the slide nut 53 while suppressing an increase in the dimension in the Y-axis direction.

A lid member 19 is arranged on one side of the first support portion 11 in the axial direction. The cover member 19 covers the gear train 4 from one side in the axial direction. The lid member 19 prevents dust and the like from adhering to the gear train 4 and suppresses deterioration of power transmission efficiency in the gear train 4.

The lid member 19 has a plate-shaped bottom portion 19a that is perpendicular to the motor axis J1, and an outer wall portion 19b that extends from the outer edge of the bottom portion 19a to the other side in the radial direction. The bottom portion 19a faces the gear train 4 in the axial direction. Holding holes 19p, 19q, and 19r are provided on the surface of the bottom portion 19a facing the other side in the axial direction. The ends of the drive shaft 30, the intermediate shaft 11a, and the lead screw 51 on one side in the axial direction are inserted into the holding holes 19p, 19q, and 19r, respectively. Thereby, the drive shaft 30, the intermediate shaft 11a, and the lead screw 51 are rotatably supported by the lid member 19 at the tips on one axial side.

According to this embodiment, the drive shaft 30, the intermediate shaft 11a, and the lead screw 51 are supported on both sides in the axial direction with respect to the gears they respectively hold. Therefore, the rotation of the drive shaft 30, the intermediate shaft 11a, and the lead screw 51 is stabilized, and the power transmission efficiency in the gear train 4 can be increased.

The second support portion 12 supports the other end of the slide mechanism 5 in the axial direction. The second support portion 12 is provided with a third holding hole 12j and a fourth holding hole 12k that penetrate in the axial direction and are lined up in the X-axis direction.

The third holding hole 12j extends along the slide axis J3. A ball bearing 12c is arranged in the third holding hole 12j. A lead screw 51 is inserted into the ball bearing 12c. The ball bearing 12c rotatably supports the other end of the lead screw 51 in the axial direction. That is, the second support portion 12 rotatably supports the other end of the lead screw 51 in the axial direction via the ball bearing 12c.

The other end of the guide shaft 52 in the axial direction is press-fitted into the fourth holding hole 12k. Thereby, the other end of the guide shaft 52 in the axial direction is fixed to the frame 10. Further, the second support portion 12 supports the other end of the guide shaft 52 in the axial direction.

The first beam portion 15 extends between the drive unit 2 and the slide mechanism 5 along the axial direction. The first beam portion 15 connects the first support portion 11 and the second support portion 12. According to this embodiment, the support parts (first support part 11 and second support part 12) that support both ends of the slide mechanism 5 are connected by the first beam part 15. That is, both ends of the slide mechanism 5 are supported by the frame 10, which is a single member. Therefore, the parallelism of the lead screw 51 and the guide shaft 52 of the slide mechanism 5 can be easily maintained, and the driving efficiency of the slide mechanism 5 can be improved.

The first beam portion 15 extends from the surface of the first support portion 11 facing the other side in the axial direction toward the other side in the axial direction. On the other hand, an intermediate shaft 11a is provided on a surface of the first support portion 11 facing one side in the axial direction. That is, the first beam portion 15 and the intermediate shaft 11a each extend from the opposite surface of the first support portion 11. Further, the intermediate shaft 11a is arranged coaxially with the first beam portion 15. Thereby, the first beam portion 15 can increase the rigidity of the intermediate shaft 11a and suppress vibrations of the intermediate shaft 11a. In addition, when the frame 10 is manufactured by molding, the intermediate shaft 11a is arranged coaxially with the first beam portion 15, which improves the flow of the raw material and increases the filling rate of the material into the intermediate shaft 11a. be able to.

The second beam portion 16 connects the first support portion 11 and the second support portion 12. Moreover, the slide mechanism 5 is arranged between the first beam part 15 and the second beam part 16. According to this embodiment, the frame 10 is provided in a frame shape so as to surround the slide mechanism 5. Thereby, the rigidity of the frame 10 can be increased, and even if an impact or the like is applied to the frame 10, deformation of the frame 10 is suppressed, and deterioration of the drive efficiency of the slide mechanism 5 can be suppressed. Moreover, since the frame 10 is frame-shaped, it is easy to improve the molding accuracy of the frame 10 when the frame 10 is manufactured by molding.

The fixing portion 13 has a plate shape extending along the XZ plane. Each fixing portion 13 is provided with a fixing hole 13p penetrating in the thickness direction. A fixing screw for fixing the geared motor 1 to an external member (not shown) is inserted into the fixing hole 13p.

Here, the three fixing parts 13 are respectively referred to as a first fixing part 13A, a second fixing part 13B, and a third fixing part 13C. The first fixing portion 13A is connected to one surface of the first support portion 11 in the axial direction. The second fixing portion 13B is connected to the surface of the second support portion 12 facing the other side in the axial direction. The third fixing portion 13C is connected to the surface of the second beam portion 16 facing the -X side.

According to this embodiment, the frame 10 has a fixing portion 13 for fixing to an external member, and supports the slide mechanism 5 that transmits power to an external device. Therefore, the positional accuracy of the output portion relative to the external member can be easily improved, and the power of the motor 21 can be efficiently transmitted to the external device.

In FIG. 2, a fourth fixing part 13V, which is a modification of the fixing part 13, is illustrated with imaginary lines. For example, it is preferable that the fourth fixing part 13V is provided on the frame 10 instead of the second fixing part 13B. The fourth fixing part 13V has a plate shape extending along the XZ plane, like the first fixing part 13A, the second fixing part 13B, and the third fixing part 13C.

The fourth fixing part 13V is arranged on the side of the other axial end of the guide shaft 52 when viewed from the plate thickness direction (Y-axis direction) of the fixing part 13. Similarly, the first fixing portion 13A is arranged on the side of one end of the guide shaft 52 in the axial direction. That is, when viewed from the thickness direction of the fixing part 13, two of the plurality of fixing parts (the first fixing part 13A and the fourth fixing part 13V) are arranged on both sides of the guide shaft 52 in the axial direction, respectively. Furthermore, when viewed from the plate thickness direction (Y-axis direction) of the fixing portion 13, each of the fixing holes 13p of the first fixing portion 13A and the fourth fixing portion 13V is located on an extension line of the guide shaft 52.

The driving force of the slide nut 53 and the external force transmitted from the member to be driven by the slide nut 53 are transmitted to the guide shaft 52 . According to this modification, since the frame 10 is fixed to the external member at both ends of the guide shaft 52, the guide shaft 52 can be stably fixed. Therefore, the guide shaft 52 is less likely to deform even when subjected to force, and can assist in the smooth sliding movement of the slide nut 53.

FIG. 3 is a plan view of a modified geared motor 101. Similar to the embodiment described above, the geared motor 101 of this modification includes a drive unit 102, a slide mechanism 105, a gear train 104, and a frame 110. Similar to the embodiments described above, the slide mechanism 105 includes a lead screw 151 and a guide shaft 152 that extend in the axial direction, and a slide nut 153 that is inserted into the lead screw 151 and the guide shaft 152. Further, the frame 110 has a plurality of fixing parts 113 for fixing to an external member.

As shown in FIG. 3, two of the plurality of fixing parts 113 are arranged on both sides of the guide shaft 152 in the axial direction when viewed from the thickness direction of the fixing part 113. Moreover, the fixing hole 113p provided in each fixing part 113 is located on the extension line of the guide shaft 152 when viewed from the thickness direction of the fixing part 113. Therefore, similarly to the above-described modification, the guide shaft 152 can be stably fixed, and the slide nut 153 can operate smoothly.

The embodiments and modifications of the present invention have been described above, but each structure and combination thereof in the embodiments are merely examples, and additions, omissions, substitutions, etc. of the structure may be made without departing from the spirit of the present invention. Other changes are possible. Moreover, the present invention is not limited by the embodiments.

DESCRIPTION OF SYMBOLS 1... Geared motor, 2... Drive unit, 4... Gear train, 5... Slide mechanism, 10... Frame, 11... First support part, 11a... Intermediate shaft, 12... Second support part, 13... Fixed part, 13p... Fixed Hole, 15... First beam part, 16... Second beam part, 19... Lid member, 19p, 19q, 19r... Holding hole, 20... Motor part, 21... Motor, 21a... Rotor, 30... Drive shaft, 32... Planetary gear mechanism, 41... Drive gear, 42... Intermediate gear, 43... Counter gear, 51... Lead screw, 52... Guide shaft, 53... Slide nut, J1... Motor axis line, J2... Intermediate axis line, J3... Slide axis line

Claims (9)

a drive unit having a motor part extending along the motor axis and a drive shaft rotating around the motor axis on one axial side of the motor part;
a slide mechanism having a lead screw rotatable around a slide axis parallel to the motor axis and a slide nut inserted into the lead screw;
a gear train that transmits power from the drive shaft to the lead screw;
A frame that supports the drive unit, the slide mechanism, and the gear train,
The frame has a first support part that rotatably supports one end of the drive shaft and the lead screw in the axial direction,
The gear train is
a drive gear fixed to the drive shaft extending to one side in the axial direction with respect to the first support part;
a counter gear fixed to the lead screw extending to one side in the axial direction with respect to the first support part;
an intermediate gear that meshes with the drive gear and the counter gear;
An intermediate shaft centered on an intermediate axis parallel to the motor axis is provided on a surface facing one side in the axial direction of the first support part,
A geared motor, wherein the intermediate gear is rotatably supported by the intermediate shaft. comprising a lid member that covers the gear train from one side in the axial direction,
The geared motor according to claim 1, wherein the surface of the lid member facing the other axial side is provided with a holding hole into which the ends of the drive shaft, the intermediate shaft, and the lead screw on one axial side are inserted. The motor section includes a plurality of motors stacked in the axial direction,
The geared motor according to claim 1 or 2, wherein the rotors of the plurality of motors are connected to each other in the axial direction to form a connected rotor. The drive unit has a planetary gear mechanism connected to the motor section,
The geared motor according to claim 1, wherein the drive shaft extends from the planetary gear mechanism to one side in the axial direction. The drive gear , the intermediate gear, and the counter gear are arranged in a straight line when viewed from the axial direction.
A geared motor according to any one of claims 1 to 4. The frame is
a second support part that rotatably supports the other end of the lead screw in the axial direction;
a first beam portion extending along the axial direction between the drive unit and the slide mechanism and connecting the first support portion and the second support portion;
A geared motor according to any one of claims 1 to 5. The geared motor according to claim 6, wherein the intermediate shaft is arranged coaxially with the first beam part. The frame has a second beam portion connecting the first support portion and the second support portion,
The geared motor according to claim 6 or 7, wherein the slide mechanism is disposed between the first beam portion and the second beam portion. The frame has a plurality of fixing parts each having a plate shape extending along the axial direction and provided with fixing holes penetrating in the thickness direction,
The slide mechanism has a guide shaft supported by the frame and extending parallel to the lead screw,
When viewed from the thickness direction of the fixing parts, two of the plurality of fixing parts are respectively arranged on both sides of the guide shaft in the axial direction, and each of the fixing holes is located on an extension line of the guide shaft.
A geared motor according to any one of claims 1 to 8.

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