JP5842672B2 - Dressing gear - Google Patents

Description

  The present invention relates to a dressing gear for dressing an internal gear type grindstone used for gear honing of an external gear that is a work gear.

  Such a dressing gear generally has a gear-type gear body (base metal) having substantially the same size and shape as an external gear (workpiece) that is a work gear, and a plurality of dressing gears formed on the outer periphery thereof. The surface of the tooth is formed with an abrasive layer that is electrodeposited with, for example, diamond abrasive grains, and is engaged with an internal gear-type grindstone used for gear honing of the gear to be cut. Is given and traversed to dress this internal gear type grindstone.

  Here, in such a dressing gear, the load tends to concentrate particularly on the tooth tip portion at both end portions in the tooth trace direction of the plurality of teeth formed on the outer periphery of the gear body. Progressing from both ends is pointed out, for example, in Patent Document 1. Therefore, in this Patent Document 1, a tooth tip central outer peripheral surface formed so as to form a part of a cylindrical surface is provided substantially at the center of the tooth tip surface, and the tooth tip circle diameters on both sides of this tooth tip central outer peripheral surface are set. A dressing gear has been proposed in which the load concentrated at both ends of the tooth tip is distributed or equalized by gradually decreasing toward the tooth trace direction.

  Further, in Patent Document 2, a dressing gear axial direction (tooth trace direction) at both ends of the dressing gear where damage to the dressing gear starts in this way is more than a base metal made of a diamond sintered body, single stone diamond, or the like. There has been proposed a dressing gear capable of suppressing progress of wear, peeling of a plating layer, and damage to a base metal by attaching a hard member having high hardness by brazing or electrodeposition.

JP-A-9-011129 Japanese Patent No. 4588058

  By the way, in the dressing gear described in the said patent document 1, the tooth tip circle diameter gradually decreased toward the tooth trace direction from both sides of the tooth tip center outer peripheral surface as described above is at both ends of the tooth tip part. It is larger than the tooth tip circle diameter of the workpiece, and it is inevitable that abrasive grains fall off due to the load on both sides of the tooth tip center outer peripheral surface while dressing is repeated.

  However, when such abrasive grains fall off, the dressing gear is usually replaced to perform dressing, while the replaced dressing gear peels off the abrasive layer once and then re-electrodeposits the diamond abrasive grains. Although it is reused, if dressing is continued without noticing such omission of abrasive grains, the base metal part of the gear body on which diamond abrasive grains are electrodeposited will be damaged, Even if it is re-electrodeposited, it cannot be reused, and the dressing gear must be discarded. The same applies to a normal dressing gear in which the diameter of the tip circle is constant over the tooth trace direction.

  In addition, in a dressing gear in which a hard member made of a diamond sintered body or single stone diamond is attached to both ends of a tooth tip portion as described in Patent Document 2, the cost of the dressing gear is high due to such a hard member. It is inevitable to become. Furthermore, in the dressing gears described in Patent Documents 1 and 2, it is impossible to prevent the abrasive grains from dropping off or the base metal from being damaged at the tooth surfaces at both ends of the tooth trace direction.

  The present invention has been made under such a background, and without increasing the cost, it is possible to extend the life by preventing the falling off of the abrasive grains and the damage of the base metal at both ends of the tooth trace direction. The aim is to provide a possible dressing gear.

In order to solve the above-mentioned problems and achieve such an object, the present invention comprises a gear-type gear body having a plurality of teeth formed on the outer periphery, and abrasive grains are fixed to the surfaces of the teeth. A dressing gear in which an abrasive grain layer is formed, wherein the abrasive grain layer at both ends of the plurality of teeth in the tooth trace direction is more average than the abrasive grains fixed to the small abrasive grain fixing part at the central part in the tooth trace direction. It is a large abrasive fixed part to which abrasive grains having a large particle size are fixed , and these large and small abrasive fixed parts are also formed on the tooth bottom part from the tooth tip part to the tooth surface. To do.

  Therefore, in the dressing gear configured in this way, in the above-described abrasive layer, large abrasive grains fixed with abrasive grains having an average particle size larger than the abrasive grains in the central portion of the tooth trace direction at both ends of the tooth trace direction. Since the portion is formed, the fixing strength of the abrasive grains in the abrasive layer of this large abrasive grain fixing portion can be strengthened from the tooth tip portion to the tooth surface to prevent the abrasive grains from falling off. This eliminates the need for expensive hard members and prevents peeling of the plating layer and damage to the base metal of the gear body not only at the tooth tips at both ends of the tooth trace direction but also at the tooth surface. Thus, the life of the dressing gear can be extended.

  Here, it is desirable that the average grain size of the abrasive grains fixed to the large abrasive grain fixing portion is 1.2 times or more the average particle diameter of the abrasive grains fixed to the central portion in the tooth trace direction. When the average grain size of the abrasive grains of the large abrasive grains fixing portion is less than 1.2 times the average grain size of the abrasive grains in the central portion of the tooth trace direction, the above-described abrasive by strengthening the fixing strength of the abrasive grains There is a possibility that the effect of preventing the drop-off of the grains is not sufficiently achieved.

  Further, the width of the large abrasive grain fixing part in the center line direction of the gear body is not less than 1.1 times the average grain size of the abrasive grains fixed to the large abrasive grain fixing part, and the teeth in the center line direction are It is desirable that the width be 25% or less. When the width of the large abrasive grain fixing portion is less than 1.1 times the average grain size of the large abrasive grains fixed to the large abrasive grain fixing portion, the large abrasive grains reliably adhere to the large abrasive grain fixing portion. On the other hand, when the width of the large abrasive grain fixing part exceeds 25% of the width of the tooth, the large abrasive grain fixing part is a part where the abrasive grains having a smaller average grain size in the central portion of the tooth trace direction are fixed. Therefore, the internal gear type grindstone is dressed exclusively by abrasive grains having a large average particle diameter, resulting in deterioration of surface accuracy.

  In addition, in order to fix the abrasive grains having a larger average particle diameter than the central portion at both ends in the tooth trace direction of the teeth in this way, for example, when the fixation is by electrodeposition, both ends and the central portion in the tooth trace direction of the teeth And then alternately masking and electrodepositing abrasive grains having different average particle diameters. Further, the gear main body may be divided into both end portions in the tooth trace direction and the central portion in the tooth trace direction, and may be combined after fixing abrasive grains having different grain sizes to these.

  As described above, according to the present invention, it is possible to prevent the abrasive grains from dropping off at both ends in the tooth trace direction without incurring high costs due to expensive hard members. It is possible to provide a long-life dressing gear while preventing damage.

1 is a perspective view showing a first embodiment of the present invention. It is sectional drawing along the tooth trace of the tooth tip part in embodiment shown in FIG. It is sectional drawing which shows the 2nd Embodiment of this invention. It is sectional drawing along the tooth trace of the tooth tip part in embodiment shown in FIG.

  1 and 2 show a first embodiment of the present invention. In the present embodiment, the gear body 1 is made of a metal material such as steel, and a base metal 2 is formed integrally with an external gear mold as shown in FIG. 1, and the surfaces of a plurality of teeth 3 formed on the outer periphery of the base metal 2. In addition, an abrasive grain layer 5 in which hard abrasive grains 4 such as diamond superabrasive grains are fixed to a single layer by electrodeposition or the like is formed. Further, an attachment hole 6 penetrating the base metal 2 along the center line O of the base metal 2 is opened at the center of both end faces of the base metal 2.

  Here, in the dressing gear of the present embodiment, the gear body 1 has a helical gear shape as shown in FIG. 1, and the teeth 3 of the base metal 2 are arranged on the outer peripheral side with respect to the center line O. The tooth tip portion that faces and the tooth surface that faces the circumferential direction are formed so as to form a continuous twisted surface without any step. Further, in the present embodiment, the tooth bottom portions of the teeth 3 are also continuously formed on the cylindrical surface centering on the center line O, and both end surfaces facing the center line O direction of the base metal 2 are attached to the mounting surface. A flat surface perpendicular to the center line O extends from the opening of the hole 6 to the tooth tip of the tooth 3. However, as shown in FIG. 2, chamfering with a small width is applied to the tooth tip portion of the tooth 3 of the base metal 2 and the intersecting ridge line portion between the tooth surface and the end surface.

  The abrasive layer 5 has both ends of the teeth 3 in the direction of the streak as large abrasive fixed portions 5A to which abrasive grains 4A having a large average particle size are fixed, and these large abrasive fixed portions 5A. The central portion of the tooth 3 in the direction of the tooth trace is a small abrasive fixed part 5B to which abrasive grains 4B having an average particle size smaller than the abrasive grains 4A of the large abrasive fixed part 5A are fixed. In addition, these large and small abrasive grain fixing | fixed part 5A, 5B is formed over the tooth surface from the tooth tip part of the tooth | gear 3, and is formed also in the tooth bottom part in this embodiment. Further, at both end portions in the tooth trace direction, the abrasive grains 4A are fixed to the outer peripheral portion of the end face of the base metal 2 to a position deeper than the depth of the bottom of the teeth to form large abrasive fixed portions 5A.

  Further, in the present embodiment, the average particle diameter of the abrasive grains 4A fixed to the large abrasive grain fixing part 5A is the average particle diameter of the abrasive grains 4B fixed to the small abrasive grain fixing part 5B at the central portion in the tooth trace direction. The average particle size is 1.2 times or more. However, it is desirable that the average grain size of the abrasive grains 4A of the large abrasive grain fixing portion 5A is about four times the average grain size of the abrasive grains 4B of the small abrasive grain fixing portion 5B. Further, the width of the large abrasive grain fixing portion 5A in the direction of the center line O of the gear body 1 is at least 1.1 times the abrasive grain 4A fixed to the large abrasive grain fixing portion 5A, for example, 1 mm. In addition to the above, the range is 25% or less of the width of the tooth 3 in the direction of the center line O.

  In addition, the abrasive grains 4A and 4B having different average particle diameters are fixed to the both ends and the central portion of the teeth 3 of the base metal 2 integrally formed as described above to fix the large abrasive fixed part 5A and the small abrasive. In order to form the abrasive layer 5 composed of the grain fixing portion 5B, when fixing is performed by electrodeposition as in this embodiment, the large abrasive grain fixing portion 5A and the teeth 3 of the base metal 2 before electrodeposition Masking is applied to one of the portions where the small abrasive fixed portion 5B is formed, electrodepositing abrasive grains 4 having an average particle size corresponding to the other, and then masking is applied to the other electrodeposited abrasive grains 4 together. One masking may be removed and the corresponding abrasive grains 4 having an average particle diameter may be electrodeposited.

  In the dressing gear configured as described above, the abrasive grains 4A having an average grain size larger than the abrasive grains 4B of the small abrasive grain fixing portion 5B at the center are fixed to the both ends of the teeth 3 in the tooth trace direction in the abrasive layer 5. A large abrasive grain fixing portion 5A is formed, and the abrasive grains 4A fixed to the large abrasive grain fixing portion 5A have a large contact area with a fixing layer such as a plating layer, so that the fixing strength is high. Therefore, without using an expensive hard member such as a diamond sintered body or single stone diamond, it is possible to prevent the abrasive grains 4A from falling off from the tip portion of the tooth 3 to the tooth surface at both ends in the tooth trace direction. In addition, it is possible to prevent the peeling of the fixing layer and the damage to the base metal 2 due to the falling off of the abrasive grains 4A, thereby extending the life of the dressing gear.

  In the present embodiment, the average particle size of the abrasive grains 4A fixed to the large abrasive particle fixing portion 5A is 1.2 times or more than the average particle size of the abrasive particles 4B fixed to the small abrasive particle fixing portion 5B. The average particle size is set to increase the contact area of the abrasive grains 4A to the fixing layer in the large abrasive grain fixing portion 5A, thereby strengthening the fixing strength and reliably preventing the abrasive grains 4A from dropping off. it can. However, when the magnification of the average grain size becomes too large, when the abrasive grains 4 are fixed as a single layer as described above to form the abrasive grain layer 5, the fixed layer of the abrasive grains 4A having a large average grain diameter. Since the amount of burying becomes small, the contact area cannot be secured, and conversely, the amount of burying of the abrasive grains 4B having a small average particle size becomes large and the abrasive grains 4B may be buried in the fixing layer. As described above, it is desirable that the average grain size of the abrasive grains 4A of the large abrasive grain fixing part 5A is about four times the average grain size of the abrasive grains 4B of the small abrasive grain fixing part 5B.

  Furthermore, in the present embodiment, the width of the large abrasive grain fixing portion 5A in the direction of the center line O of the gear body 1 is 1.1 times or more the average particle size of the abrasive grains 4A fixed to the large abrasive grain fixing portion 5A. This also ensures that the abrasive grains 4A having a large average grain size are firmly fixed to form the large abrasive grain fixing portions 5A having a necessary width, and the abrasive grains 4A drop off at both ends of the teeth 3 in the tooth trace direction. Can be reliably prevented. That is, when the width of the large abrasive grain fixing portion 5A is so small that it is less than 1.1 times the average particle size of the abrasive grains 4A fixed to the large abrasive grain fixing portion 5A, it is ensured that at least 1 One or more abrasive grains 4 (large abrasive grains 4A) cannot be fixed, and accordingly, there is a possibility that peeling of the fixing layer and damage to the base metal cannot be surely prevented.

  However, conversely, if the width of the large abrasive grain fixing portion 5A is too wide and the ratio of the teeth 3 to the width in the direction of the center line O is larger than that of the small abrasive grain fixing portion 5B, the large abrasive grain fixing portion 5A Since the internal gear-type grindstone is dressed exclusively by the fixed large abrasive grains 4A having a large average particle diameter, the surface accuracy of the internal gear-type grindstone is degraded, and the surface accuracy of the work gear is also degraded. There is a risk of it. For this reason, it is desirable that the width of the large abrasive grain fixing portion 5A in the center line O direction is 25% or less of the width of the teeth 3 in the direction of the center line O at both ends in the tooth trace direction.

  Next, FIGS. 3 and 4 show a second embodiment of the present invention, and the same reference numerals are assigned to the same parts as those in the first embodiment shown in FIGS. Is omitted. 3 shows a cross section along the tooth trace of the tooth bottom portion of the tooth 3, and the base metal 2 part inside this shows a cross section along the center line O of the base metal 2. Show.

  In the present embodiment, the base metal 2 of the gear body 1 is composed of a pair of end plate members 2A and 2B both made of a metal material such as steel, and a sandwiching member 2C sandwiched between these end plate members 2A and 2B. The end plate members 2A, 2B and the sandwiching member 2C are integrated to form a base metal 2, and a plurality of teeth 3 are provided on the outer periphery thereof. Each is formed continuously. And the part formed in end plate member 2A, 2B among the abrasive grain layers 5 formed in the surface of this tooth | gear 3 was made into the large abrasive grain adhering part 5A, and it was formed in the clamping member 2C between them The portion is a small abrasive fixed portion 5B.

  Here, the pair of end plate members 2A and 2B are formed in an annular plate shape having the same shape and the same size except for the tooth 3 portion, and one of the end plate members (the left end plate member in FIG. 3). A plurality of screw holes 21 penetrating in the center line O direction are formed in 2A at equal intervals in the circumferential direction, and the other end plate member (right end plate member in FIG. 3) 2B is sandwiched as described above. A stepped hole in which the end plate member 2A side is a small diameter portion 22A and the opposite side is a large diameter portion 22B at a position coaxial with these screw holes 21 with the member 2C sandwiched and the teeth 3 continuous. A plurality of 22 are formed so as to penetrate in the direction of the center line O.

  Further, the sandwiching member 2C is also formed in an annular plate shape except for the tooth 3 portion, and the inner peripheral portion thereof serves as the mounting hole 6, and the opening of both ends of the mounting hole 6 in the center line O direction is also provided. The circumference has an outer diameter large enough to fit the inner peripheral portions of the pair of end plate members 2A, 2B in the shape of an annular plate, and is equal to the thickness of the end plate members 2A, 2B in the direction of the center line O. It is an annular boss portion 23 centering on a center line O protruding on both sides in thickness. Further, in a state in which the teeth 3 are sandwiched between the pair of end plate members 2A and 2B and the teeth 3 are continuous, the end plate members 2A and 2B are stepped at positions coaxial with the screw holes 21 and the stepped holes 22. A through hole 24 having the same diameter as the small diameter portion 22A of the hole 22 is formed.

  The end plate members 2A and 2B and the sandwiching member 2C have the screw holes 21, the stepped holes 22 and the through holes 24 coaxially, and the inner peripheral portions of the end plate members 2A and 2B are connected to the sandwiching members 2C. After the teeth 3 are made continuous by being fitted to the boss portion 23, the mounting screw 25 inserted from the stepped hole 22 side is screwed into the screw hole 21, so that it is sandwiched between the pair of end plate members 2A and 2B. The mounting member 2C is sandwiched and integrated.

  Here, the mounting screw 25 has a male screw portion 25A that is screwed into the screw hole 21 at the front end portion, and a large diameter portion 22B that has a larger diameter than the small diameter portion 22A of the stepped hole 22 at the rear end portion. A head portion 25B having a smaller diameter is formed, and a cylindrical shaft portion 25C having an outer diameter that can be fitted to the small diameter portion 22A of the stepped hole 22 and the through hole 24 is formed between the male screw portion 25A and the head portion 25B. The cylindrical shaft portion 25C is fitted to the small diameter portion 22A and the through hole 24 and the male screw portion 25A is screwed into the screw hole 21, whereby the end plate members 2A and 2B and the sandwiching member 2C are As described above, the screw hole 21, the stepped hole 22, and the through hole 24 are aligned so as to be coaxial, and a continuous tooth 3 is formed.

  Therefore, even in the dressing gear of the second embodiment of the present invention configured as described above, the abrasive layer 5 at both end portions in the tooth trace direction of the plurality of teeth 3 is a small abrasive fixed portion at the center portion in the tooth trace direction. Since the abrasive grains 4A having a larger average particle size than the abrasive grains 4B of 5B are fixed, the large abrasive grains fixing portion 5A is used, so that the fixing strength of the abrasive grains 4A is strengthened to prevent dropping, and the fixing is performed accordingly. It is possible to extend the life of the dressing gear by preventing layer peeling and damage to the base metal 2 (end plate members 2A, 2B).

  In the present embodiment, both end portions in the center line O direction of the base metal 2 on which the large abrasive grain fixing portion 5A is formed are the end plate members 2A and 2B that can be divided from the sandwiching member 2C. Thus, even if the fixing strength of the abrasive grains 4A is increased, even if the abrasive grains 4A drop off or the fixing layer peels off, the abrasive grains 4A are removed after removing the end plate members 2A and 2B where the dropping or peeling has occurred. The end plate members 2A and 2B can be reused by once removing the fixing layer and refixing new abrasive grains 4A (re-electrodeposition in the case of electrodeposition). Further, even if the end plate members 2A and 2B are damaged by noticing the falling off of the abrasive grains 4A and the end plate members 2A and 2B are damaged, in the present embodiment, the damaged end plate members 2A and 2B are replaced. The sandwiching member 2C of the base metal 2 and the end plate members 2A and 2B having no damage can be used as they are.

  In order to fix the abrasive grains 4A and 4B having different average particle diameters to the teeth 3 of the end plate members 2A and 2B and the sandwiching member 2C that can be divided in this way, for example, the fixing is performed while fixing them together. In the case of the electrodeposition, the masks may be alternately masked in the same manner as in the first embodiment to electrodeposit the abrasive grains 4A and 4B, but the end plate members 2A and 2B and the sandwiching member 2C are divided. It is efficient to electrodeposit the abrasive grains 4A and 4B separately after masking the portion where the abrasive grain layer 5 is not formed. Further, when the teeth 3 are formed on the base metal 2, the end plate members 2A, 2B on which the teeth 3 are not formed and the sandwiching member 2C are integrated with the mounting screw 25, and then the teeth 3 are formed on the outer periphery thereof. Then, the continuous tooth 3 can be formed with high accuracy.

  Examples of the present invention will be given below to demonstrate the effects of the present invention. In this example, in the dressing gear based on the first embodiment, the average grain size of the abrasive grains 4A fixed (electrodeposited) to the large abrasive fixed portion 5A and fixed to the small abrasive fixed portion 5B (electrodeposition) 5) A total of five types of dressing gears of the same size and the same size are manufactured by changing the average grain size of the abrasive grains 4B, and the same dressing is used for those having the same average grain diameter of the abrasive grains 4B of the small abrasive grain fixing portion 5B. A number of internal gear-type grindstones were dressed, and the presence or absence of removal of abrasive grains and peeling of the abrasive grain layer 5 in the large abrasive grain fixing part 5A after dressing was visually confirmed. Let these be Examples 1-6.

  For comparison, an abrasive layer in which only abrasive grains having the same shape and size as those of Examples 1 to 6 and having the same average particle diameter as the abrasive grains 4B of the small abrasive grain fixing portions 5B of Examples 1 and 3 are fixed. Two kinds of dressing gears were manufactured, and dressing was performed under the same conditions to confirm that the abrasive grains dropped off and the abrasive layer peeled off at both ends of the tooth trace direction. These are referred to as Comparative Examples 1 and 2, respectively. And the result by these Examples 1-6 and Comparative Examples 1 and 2 is what the average particle diameter of the abrasive grain 4B of the small abrasive grain fixed part 5B is common, and the average particle diameter of the abrasive grains 4A and 4B (comparison) Examples 1 and 2 show only the abrasive grains 4B), the magnification of the abrasive grains 4A with respect to the abrasive grains 4B (comparative examples 1 and 2 are 1 times), and the number of dresses are shown in Tables 1 and 2 below.

  The specifications of the dressing gear are all the number of teeth 30, the twist angle 30 ° RH, the outer diameter 73.7 mm, the width 3 of the teeth 3 in the direction of the center line O, and the large abrasive grain fixing portion 5A of Examples 1-6. The width of each of the both ends was 4 mm, and the width of the small abrasive grain fixing portion 5B was 16 mm. Moreover, the internal gear type grindstone to be dressed has 121 teeth, a twist angle of 18 °, an outer diameter of 300 mm, a grindstone width of 26 mm, and the abrasive grains are WA abrasive grains having a grain size of 100, a bonding degree of Z, and a structure of 8, module 2, pressure It was for grinding a work gear with an angle of 14.5 °, the number of teeth of 30, a twist angle of 30 ° RH, an outer diameter of 73.3 mm, and a tooth width of 20 mm. Furthermore, the dressing conditions were a grinding wheel rotational speed of 55 rpm, a feed rate of 200 mm / min, a traverse end cut amount of 0.003 mm, and a cut amount per dress of 0.06 mm.

  From the results of Tables 1 and 2, in the dressing gears of Comparative Examples 1 and 2 in which the abrasive grains having the same average particle diameter were electrodeposited over the entire tooth trace direction, both of the dressings after the predetermined number of dressings were completed. In the dressing gears of Examples 1 to 6 according to the present invention, the abrasive grains dropped off and the fixing layer (plating layer) was peeled off at both ends of the teeth in the tooth trace direction. It can be seen that, in the large abrasive grain adhering portions 5A at both ends in the direction of the muscle, not only the adhesion layer was peeled but also the abrasive grains did not fall off at the tooth tip.

DESCRIPTION OF SYMBOLS 1 Gear main body 2 Base metal 2A, 2B End plate member 2C Clamping member 3 Tooth 4 Abrasive grain 4A Abrasive grain with large average grain diameter 4B Abrasive grain with small average grain diameter 5 Abrasive grain layer 5A Large abrasive grain fixed part 5B Small abrasive Grain fixing part 21 Screw hole 22 Stepped hole 23 Boss part 24 Through hole 25 Mounting screw O Center line of gear body 1

Claims (4)

A dressing gear comprising a gear-type gear body having a plurality of teeth formed on the outer periphery and having an abrasive layer formed by adhering abrasive grains to the surface of the teeth, wherein the tooth trace direction of the plurality of teeth the abrasive grain layer at both ends is large abrasive grains secured portion large abrasive grains are fixed with an average particle diameter than the abrasive grains secured to the small abrasive anchor portion in the tooth trace direction center portion, these large and small abrasive A dressing gear characterized in that the grain fixing part is also formed on the tooth bottom part from the tooth tip part to the tooth surface .   The average grain size of the abrasive grains fixed to the large abrasive grain fixing portion is 1.2 times or more than the average particle diameter of the abrasive grains fixed to the central portion in the tooth trace direction. Item 12. The dressing gear according to Item 1.   The width of the large abrasive grain fixing portion in the center line direction of the gear body is 1.1 times or more the average grain size of the abrasive grains fixed to the large abrasive grain fixing portion, and the width of the teeth in the center line direction. The dressing gear according to claim 1 or 2, wherein the dressing gear is 25% or less.   The dressing gear according to claim 1, wherein the gear main body is capable of dividing the both ends of the tooth trace direction and the center part of the tooth trace direction.

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