JP5169803B2 - Linear motion guide device - Google Patents

Description

  The present invention relates to a rolling element non-circulating linear motion guide device.

An example of the configuration of a conventional rolling element circulation type linear motion guide device will be described. The linear motion guide device includes a guide rail having a substantially square cross section extending in the axial direction, and a slider having a substantially U-shaped cross section attached to the guide rail. Two or four rolling element raceway surfaces are formed in the axial direction.
The slider includes a slider body and end caps attached to both end portions in the axial direction. This slider body has a rolling element raceway surface facing the rolling element raceway surface of the guide rail on the inner side surface of both sleeve parts, and has a straight path that penetrates the thick part of the sleeve part in the axial direction. . And the rolling element rolling path is formed by the both rolling element raceway surfaces which oppose.

The end cap has a curved path that allows the rolling element rolling path to communicate with a straight path parallel to the rolling element rolling path. The straight road and the curved roads at both ends constitute a rolling element return path for sending the rolling elements from the end point of the rolling element rolling path to the starting point. The rolling element circulation path is composed of the rolling element return path and the rolling element rolling path. A road is formed. A large number of rolling elements made of steel balls or the like are loaded in the rolling element circulation path.
The slider attached to the guide rail moves smoothly along the guide rail through the rolling of the rolling element in the rolling element rolling path. During the movement, the rolling element moves in the rolling element circulation path in the slider. Roll infinitely while rolling.

  In the linear motion guide device in which the rolling element moves and circulates inside the slider, that is, in the linear motion guide device of the rolling element circulation type, the rolling element enters or exits the load zone. In such a case, minute fluctuations (hereinafter, also referred to as rolling element passing vibration) occur due to imbalance of the load acting on the rolling elements. Although this minute variation is a very minute variation, there is a case where it becomes a problem in a linear motion guide device for a die processing machine and the like that requires high accuracy.

  On the other hand, there is a linear motion guide device that does not include the rolling element return path as described above and does not circulate as described above (hereinafter referred to as a rolling element non-circulating linear motion guide device). . For example, an EPF series linear motion guide device manufactured by THK Corporation may be mentioned. In the conventional rolling element non-circulating linear motion guide device, since the rolling element does not come out of the load zone, it is considered that the rolling element passing vibration basically does not occur. However, in this type of linear motion guide device, the length of the slider in the axial direction needs to be the total length of the range that receives the load from the rolling element and 1/2 of the stroke. There was a problem that it was difficult to realize long strokes.

Therefore, the rolling element non-circulating linear motion guide device disclosed in Patent Document 1 has a structure that can receive the load from the rolling element over the entire length of the slider in the axial direction. As with the guide device, it is easy to increase the stroke. Further, the rolling element passing vibration is not generated by aligning the axial positions of the respective rolling elements of the plurality of rolling element rows by using the rolling element holder.
JP 2008-115921 A

In general, when a linear motion table such as an XY table is configured using a linear motion guide device, a linear motion guide device having a plurality of sliders may be employed depending on the size and mass of the table. For example, a linear motion table may be configured using two guide rails including two sliders.
Considering the rolling element passing vibration, it is advantageous to make the number of sliders one and increase the axial length. However, if the slider is long, it becomes difficult to process or the shape accuracy of the rolling element raceway surface of the slider (for example, It is difficult to make the accuracy (straightness) highly accurate over the entire length of the slider, so this is not always a good solution if the table is large.

  In such a rolling element non-circulating linear motion guide device having a plurality of sliders, there may be a problem when the stroke is long with respect to the span (axial distance) between the sliders. For example, in a linear motion guide device having two sliders, when a rolling element cage is used for each slider, the axial ends of both rolling element cages are positioned between the two sliders. However, when the amount of movement of the slider increases, one slider reaches the axial ends of the two rolling element cages facing each other. And if the axial direction edge part of a rolling element holder enters into a load zone, since a rolling element does not exist after an axial direction edge part, it becomes impossible to receive a load. When the slider further moves, the rolling element holder comes off from the slider, and there is no longer any rolling element that receives the load, and the rolling element holder can move to a position far away from the slider.

In order to prevent such a problem from occurring, it is necessary to set the length of each rolling element cage so as to cover the stroke range of each slider. Even if the length of the moving body holder is extended, the axial distance between the two sliders needs to be large.
Accordingly, the present invention solves the above-described problems of the prior art, and in a rolling element non-circulating linear motion guide device having a plurality of sliders, the stroke is long with respect to the axial distance between the sliders. Even so, an object of the present invention is to provide a linear motion guide device in which the rolling element cage is not likely to be detached from the slider and receive a load.

  In order to solve the above-described problems, the present invention has the following configuration. That is, the linear motion guide device according to claim 1 of the present invention has a guide rail having a rolling element raceway surface extending in the axial direction on the outer surface and a rolling element raceway surface facing the rolling element raceway surface of the guide rail. The slider is attached to the guide rail so as to be relatively movable in the axial direction, and a plurality of rolling elements are arranged along the axial direction on the rolling element raceway surface of the guide rail, and a part of the rolling element raceways. A rolling element row arranged between the surfaces, and a rolling element row that holds the rolling element row freely on the rolling element raceway surface of the guide rail and moves in the same direction as the slider with relative movement of the slider. A linear motion guide device comprising a moving body holder, comprising a plurality of the sliders and a single rolling body holder, the rolling body holder being disposed between the plurality of sliders and the guide rail. Are arranged in And wherein the door.

  In this way, if a configuration using one rolling element holder for a plurality of sliders is adopted, the rolling element through which one slider has passed can be passed through by another slider. Even when the stroke is long with respect to the directional distance, there is no possibility that the rolling element retainer will be detached from the slider and cannot receive a load. Therefore, it is easy to shorten the axial distance between the sliders and to ensure a long stroke.

A linear motion guide device according to a second aspect of the present invention is the linear motion guide device according to the first aspect, wherein the moving amount of the rolling element cage is set to ½ of the moving amount of the slider. One or more of the plurality of sliders and less than all of the plurality of sliders are provided with movement error preventing means for preventing an error in the moving amount of the moving body holder.
In a rolling element non-circulating linear motion guide device provided with a rolling element holder, the rolling element holder moves in the same direction as the slider with the relative movement of the slider, and the amount of movement of the rolling element holder is in principle Is half of the slider travel, but in reality, slippage between the rolling element raceway surfaces and the rolling element, or error in the distance from the center of rotation of the rolling elements to the contact point with the rolling element raceway surface, As a result, the amount of movement of the rolling element cage does not become exactly ½ of the amount of movement of the slider, and an error occurs. As a result, the axial position of the rolling element cage with respect to the slider and the guide rail gradually shifts from the normal position as the slider moves (hereinafter referred to as the positional deviation of the rolling element cage). There is also.)

  Accordingly, in the rolling element non-circulating linear motion guide device provided with the rolling element holder, a movement error that suppresses the positional deviation of the rolling element holder by setting the movement amount of the rolling element holder to exactly ½ of the movement amount of the slider. Prevention means are provided. However, if the movement error prevention means is provided for each of the plurality of sliders, the number of parts increases and the assembly of the linear motion guide device takes time and effort, which increases the manufacturing cost of the linear motion guide device. There was a problem that.

  When a linear motion table such as an XY table is configured using a linear motion guide device, a plurality of sliders attached to one guide rail are fixed to one table constituting the linear motion table, Since the axial distance between the sliders does not change with movement, the movement error prevention means does not need to be provided in the total number of the plurality of sliders, and may be provided in at least one. If it does so, position shift of a rolling element holder will not arise in all sliders. Since it is not necessary to provide movement error prevention means for all sliders, the number of parts can be reduced and the time and effort for assembling the linear motion guide device can be reduced. Can be reduced.

  Furthermore, the linear motion guide device according to claim 3 of the present invention is the linear motion guide device according to claim 2, wherein the first rack is attached to the slider so as to be along the axial direction, and is along the axial direction. The movement error prevention means is configured by a rack and pinion comprising a second rack attached to the guide rail and a pinion rotatably attached to the rolling element holder and meshing with both racks. It is characterized by being.

With the rack and pinion having such a configuration, the movement error preventing means can be easily configured.
Furthermore, the linear motion guide device according to claim 4 of the present invention is the linear motion guide device according to claim 3, wherein a plurality of the pinions are attached to the rolling element holder along the axial direction. The axial distance between the pinions is shorter than the axial length of the first rack.

With such a configuration, even if the slider and the rolling element cage are moved, there is no fear that the pinion comes off from the first rack attached to the slider and does not mesh, and the pinion that meshes with the first rack It will always exist.
Furthermore, the linear motion guide device according to claim 5 of the present invention is the linear motion guide device according to claim 2, wherein a first rack attached to the rolling element holder along the axial direction, and a shaft The movement error preventing means is constituted by a rack and pinion comprising a second rack attached to the guide rail so as to be along the direction and a pinion rotatably attached to the slider and meshing with both racks. The pinion is a two-stage gear in which a first gear meshing with the first rack and a second gear meshing with the second rack are fixed to a concentric shaft, and the second gear The pitch circle diameter of the first gear is twice the pitch circle diameter of the first gear, and the first rack is attached to the axial end of the rolling element cage.

With such a configuration, the pinion can always mesh with the first rack and the second rack, and therefore, it is sufficient to provide one pinion .

  In the linear motion guide device of the present invention, even when the stroke is long with respect to the axial distance between the sliders, there is no possibility that the rolling element retainer is detached from the slider and cannot receive a load.

An embodiment of a linear motion guide device according to the present invention will be described in detail with reference to the drawings.
[First embodiment]
FIG. 1 is a side view showing an embodiment of a linear guide device according to the present invention. FIG. 2 is a front view of the linear motion guide device of FIG. 1 viewed from the axial direction.
First, the configuration of the linear motion guide device of the present embodiment will be described. A plurality (two in FIG. 1) of sliders 2A and 2B are assembled on a guide rail 1 having a substantially square cross section extending in the axial direction so as to be relatively movable in the axial direction. The cross-sectional shape of the sliders 2A and 2B is substantially U-shaped, and the cross-sectional shape of the inner surface thereof is a shape along the cross-sectional shape of the outer surface of the guide rail 1. Two rolling element raceway surfaces 10, 10 extending in the axial direction are formed on both side surfaces 1a, 1a of the guide rail 1, respectively.

  Further, two rolling element raceway surfaces 11 and 11 facing the rolling element raceway surfaces 10 and 10 of the guide rail 1 are formed on the inner side surfaces of both sleeve portions 6 and 6 of the sliders 2A and 2B, respectively. Four rolling element rolling paths are formed by the rolling element raceway surfaces 10, 10, 10, 10 of the guide rail 1 and the rolling element raceway surfaces 11, 11, 11, 11 of both sleeve portions 6, 6. These rolling element rolling paths extend in the axial direction. The number of rolling element raceway surfaces 10 and 11 provided in the guide rail 1 and the sliders 2A and 2B is not limited to two on one side, but may be one or more on one side, for example.

Further, a plurality of rolling elements 3 arranged along the axial direction are arranged on each rolling element raceway surface 10 of the guide rail 1 so as to be freely rotatable, and a rolling element row is formed by these rolling elements 3. ing. In FIGS. 1 and 2, the rolling element 3 is a roller, but a ball may be used.
Further, between the inner surfaces of the sliders 2 </ b> A and 2 </ b> B and the outer surface of the guide rail 1, a single rolling element holder 4 is disposed on the rolling element raceway surface 10 to hold the rolling element 3 in a freely rolling manner. . The cross-sectional shape of the rolling element cage 4 is substantially U-shaped along the cross-sectional shape of the inner surfaces of the sliders 2A and 2B and the cross-sectional shape of the outer surface of the guide rail 1, and both sides thereof (the side surface 1a of the guide rail 1). And a portion sandwiched between the sleeve 2 of the slider 2A and 2B) and a plurality of pockets 4a for accommodating the rolling element 3 and holding the rolling element 3 so as to be freely rollable are formed side by side along the axial direction. Has been. And the pocket 4a is formed so that the axial direction position of the rolling element 3 arranged on the rolling element raceway surface 10 is aligned with the axial position of the rolling element 3 arranged on the rolling element raceway surface 10 of the other strip. Has been.

Since the axial length of the rolling element cage 4 is sufficiently longer than the total axial length of the sliders 2A and 2B, a part of the rolling element row is located between the rolling element raceway surfaces 10 and 11 (that is, the rolling element). However, the remaining part of the rolling element row is not arranged between the rolling element raceway surfaces 10 and 11, and is exposed as shown in FIG.
In such a linear motion guide device, the sliders 2A and 2B assembled to the guide rail 1 are moved in the axial direction along the guide rail 1 through the rolling of the rolling element 3 in the rolling element rolling path. It can move smoothly. At this time, the rolling element holder 4 moves in the same direction as the sliders 2A and 2B as the sliders 2A and 2B move. Even if the sliders 2A and 2B move, the rolling element 3 held by the rolling element holder 4 is present at the moved position, so that the movement can be continued through the rolling of the rolling element 3. Therefore, in the linear motion guide device of the present embodiment, the rolling element passing vibration is suppressed, and a long stroke of the sliders 2A and 2B is secured.

  In addition, if a configuration using one rolling element holder 4 for a plurality of sliders 2A and 2B is adopted, the rolling element 3 through which one slider 2A has passed can pass through the other slider 2B. Even when the stroke is long with respect to the axial distance between the sliders 2A and 2B, there is no possibility that the rolling element retainer 4 can be detached from the sliders 2A and 2B and cannot receive a load. Therefore, it is easy to shorten the axial distance between the sliders 2A and 2B and to secure a long stroke.

  In such a linear motion guide device, a movement error prevention means for preventing an error from occurring in the movement amount of the rolling element holder 4 is provided in one or more of the plurality of sliders 2A and 2B. preferable. For example, when the number of sliders is two as shown in FIGS. When the number of sliders is 3 or more, one of them may be provided with a movement error preventing means, or 2 or more and less than the total number.

  In a conventional rolling element non-circulating linear motion guide device, the rolling element holder moves in the same direction as the slider with the relative movement of the slider, and the amount of movement of the rolling element holder is in principle the movement of the slider. Although the amount is half of the amount, in reality, the error as described above occurs, and the displacement of the rolling element holder often occurs. Therefore, the linear motion guide device is provided with a movement error preventing means for suppressing the positional deviation of the rolling element holder by setting the moving amount of the rolling element holder to exactly ½ of the movement amount of the slider. When the movement error preventing means is provided in all, there is a problem that the manufacturing cost of the linear motion guide device is increased due to an increase in the number of parts.

  The linear motion guide device of the present embodiment is mainly used as a component constituting a linear motion table such as an XY table. In this case, a plurality of sliders 2A and 2B attached to one guide rail 1 are Since it is fixed and connected to one table (not shown) constituting the linear motion table, all sliders 2A can be provided if the movement error preventing means is provided in one or more of the plurality of sliders 2A, 2B. , 2B, no displacement of the rolling element holder 4 occurs. Since it is not necessary to provide the movement error preventing means in all the sliders 2A and 2B, the number of parts can be reduced and the time and effort for assembling the linear motion guide device can be reduced. The manufacturing cost can be reduced.

  The configuration of the movement error preventing means is such that the amount of movement of the rolling element holder 4 is set to ½ of the amount of movement of the slider 2A, and an error in the amount of movement of the rolling element holder 4 can be prevented. There is no particular limitation. However, the first rack 21 attached to the slider 2A along the axial direction, the second rack 22 attached to the guide rail 1 along the axial direction, and the rolling element holder 4 are rotatable. The rack and pinion 5 including the pinion 23 attached and meshed with both racks 21 and 22 preferably constitutes a movement error preventing means. The axial length of the first rack 21 may be the same as the axial length of the slider 2 </ b> A, and the axial length of the second rack 22 may be the same as the axial length of the guide rail 1.

  In FIG. 2, the first rack 21 is attached to the lower surface of the sleeve 6 of the slider 2 </ b> A, and the second rack 22 is attached to the side surface 1 a of the guide rail 1. If the movement error preventing means comprising the rack and pinion 5 is provided on the side of the guide rail 1 in this way, the pinion 23 is moved to the side after the assembly of the guide rail 1, the rolling element holder 4, and the sliders 2A and 2B. Assembling is easy. However, the movement error prevention means composed of the rack and pinion 5 is not limited to the side portion of the guide rail 1 and may be provided at the upper portion. That is, as shown in FIG. 3, the first rack 21 may be attached to the inner lower surface of the slider 2 </ b> A, and the second rack 22 may be attached to the upper surface of the guide rail 1.

  In addition, when the pinion 23 is attached to the rolling element holder 4, when the slider 2A and the rolling element holder 4 are moved, the pinion 23 is detached from the first rack 21 attached to the slider 2A and is not engaged. There is a risk that. Therefore, a plurality of pinions 23 may be arranged along the axial direction and attached to the rolling element holder 4 so that the axial distance between the pinions 23 is shorter than the axial length of the first rack 21. Then, even if the slider 2A and the rolling element holder 4 move, the pinion 23 that meshes with the first rack 21 always exists.

  In addition, this embodiment shows an example of this invention and this invention is not limited to this embodiment. For example, the rolling element holder 4 may be composed of an integrally formed member, but a single rolling element holder 4 is configured by connecting a plurality of small cages having a short axial length in the axial direction. May be. By connecting the small cage, for example, the following advantages can be obtained. Small cages are manufactured at low cost by resin injection molding, and the optimum axial length is achieved by connecting the required number of small cages according to the stroke, span between sliders, slider axial length, etc. The rolling element holder 4 can be manufactured at low cost. The small cage may be directly connected or may be connected via a connecting member such as a rod or plate.

  In addition, a single rolling element holder 4 may be formed by connecting a plurality of rolling element holders 4 together. In that case, you may connect, for example using connection members, such as rod shape and plate shape. Depending on the configuration of the table, the part of the rolling element cage located between the two sliders may not always enter the inside of the slider. In such a case, the part that does not enter the inside of the slider is connected. They can be joined together with members.

[Second Embodiment]
FIG. 4 is a front view illustrating the second embodiment of the linear motion guide device according to the present invention as seen from the axial direction. In addition, since the structure and effect | action of the linear guide apparatus of 2nd embodiment are substantially the same as 1st embodiment, only a different part is demonstrated and description of the same part is abbreviate | omitted. Further, in FIG. 4, the same reference numerals as those in FIGS.

  The movement error preventing means in the linear motion guide device of FIG. 4 is configured by the rack and pinion 5 as in the first embodiment, but the first is attached to the rolling element holder 4 along the axial direction. A rack and pinion 5 comprising a rack 21, a second rack 22 attached to the guide rail 1 along the axial direction, and a pinion 23 rotatably attached to the slider 2A and meshing with both racks 21 and 22. It is configured. The axial length of the second rack 22 may be the same as the axial length of the guide rail 1. In FIG. 4, a second rack 22 is attached to the side surface 1a of the guide rail 1, and a pinion 23 is attached to the lower surface of the sleeve 6 of the slider 2A.

  The pinion 23 is a two-stage gear in which a first gear 23 a that meshes with the first rack 21 and a second gear 23 b that meshes with the second rack 22 are fixed to a concentric shaft. The pitch circle diameter (PCD) of the second gear 23b is twice the pitch circle diameter (PCD) of the first gear 23a. Furthermore, the first rack 21 is attached to the axial end of the rolling element holder 4.

With such a configuration, the pinion 23 can always mesh with the first rack 21 and the second rack 22, and therefore the number of pinions 23 to be provided is sufficient.
Incidentally, a linear motion guide device provided with a movement error preventing means using a two-stage gear as described above is disclosed in Japanese Patent Publication No. 7-98295. In the linear motion guide device of the publication, a pinion is attached to the guide rail, and a long hole is provided in the rolling element holder in order to engage the pinion with the rack attached to the rolling element holder and the slider, respectively. ing. The linear motion guide device of the publication is thin and has a small stroke, but there is no problem. However, in the linear motion guide device for realizing a long stroke as in the present invention, it is necessary to provide an extremely long slot. Therefore, there is a possibility that a problem occurs in the strength of the rolling element cage. In the present embodiment, since the first rack 21 is attached to the side portion of the rolling element holder 4 and the pinion 23 is engaged from the outside, it is not necessary to provide a long hole in the rolling element holder 4.

  In addition, when a plurality of sliders and one rolling element holder are assembled to one guide rail, there is a problem that it is difficult to adjust the axial distance between the sliders. If there is one rolling element holder for one slider, each slider can be moved separately. Therefore, after the slider is assembled to the guide rail, the axial distance between the sliders may be adjusted. Even when one rolling element retainer is used for a plurality of sliders, each slider can move separately if no preload is applied. However, when one rolling element retainer is used for a plurality of sliders and preload is applied, if one slider is moved, another slider will also move. It is difficult to adjust the axial distance between the sliders in the state.

  In such a case, the axial distance between the sliders can be set as follows. First, when connecting a plurality of rolling element cages with the above-mentioned connecting members, do not connect the rolling element holders with connecting members at the time of assembly. It is preferable to adjust the axial distance between the sliders in accordance with the table, and to connect the rolling element holders together with a connecting member.

  On the other hand, when the connecting members are not connected, it is necessary to set the axial distance between the sliders when the plurality of sliders and one rolling element holder are assembled to the guide rail. For example, a method of attaching a plurality of sliders to the table in advance with a predetermined axial distance and assembling the guide rails is preferable. If it is inconvenient to use a table, a dummy table having a slider mounting portion similar to a real table is prepared, and a plurality of sliders are attached in advance to the dummy table and assembled to the guide rail. is there.

  Furthermore, if it is inconvenient to use a dummy table, a method using a gap jig 30 as shown in FIG. 5 is preferable. That is, this is a method in which a plurality of sliders 2 </ b> A and 2 </ b> B are attached to the gap jig 30 in advance and assembled to the guide rail 1. The gap jig 30 includes a plurality of attachment members 31 each having a slider attachment portion, and the interval between the attachment members 31 can be adjusted to a desired value and fixed. Therefore, if the sliders 2A and 2B are attached to the respective attachment members 31 set at a desired interval and are assembled to the guide rail 1, the axial distance between the sliders 2A and 2B can be easily set.

It is a side view which shows one Embodiment of the linear guide apparatus which concerns on this invention. It is the front view which looked at the linear motion guide apparatus of FIG. 1 from the axial direction. It is the side view which fractured and showed a part of slider which explains the modification of a first embodiment. It is the front view seen from the axial direction which shows 2nd embodiment of the linear guide apparatus which concerns on this invention. It is a side view of the linear guide apparatus explaining the method using a clearance jig .

Explanation of symbols

First guide rail 2, 2A, 2B the slider 3 rolling element 4 rolling body cage 4a pocket <br/> 5 rack and pinion 10 rolling element raceway surface 11 rolling element raceway surface 21 first rack 22 second rack 23 pinion 23a first gear 23b second tooth wheel

Claims (5)

  A guide rail having an outer raceway raceway surface extending in the axial direction; a slider having a racer raceway surface facing the rolling body raceway surface of the guide rail and attached to the guide rail so as to be relatively movable in the axial direction; A plurality of rolling elements arranged along the axial direction on the rolling element raceway surface of the guide rail, a part of which is arranged between the rolling element raceway surfaces, and the rolling of the guide rail. In a linear motion guide device comprising: a rolling element holder that rotatably holds the rolling element row on a moving body raceway surface and moves in the same direction as the slider with relative movement of the slider. A linear motion guide device comprising: the slider and one rolling element holder, wherein the rolling element holder is disposed between the plurality of sliders and the guide rail.   The movement error prevention means for preventing the error in the movement amount of the rolling element holder, wherein the movement amount of the rolling element holder is ½ of the movement amount of the slider, is one of the plurality of sliders. The linear motion guide device according to claim 1, wherein the linear motion guide device is provided in a number not less than a total number.   A first rack attached to the slider along the axial direction, a second rack attached to the guide rail along the axial direction, and the both racks rotatably attached to the rolling element holder. The linear motion guide device according to claim 2, wherein the movement error preventing means is configured by a rack and pinion comprising a pinion meshing with a rack.   A plurality of the pinions are arranged along the axial direction and attached to the rolling element holder, and the axial distance between the pinions is shorter than the axial length of the first rack, respectively. The linear guide apparatus according to claim 3. A first rack attached to the rolling element holder along the axial direction; a second rack attached to the guide rail along the axial direction; and the both racks rotatably attached to the slider. The movement error prevention means is constituted by a rack and pinion comprising a pinion meshing with a rack,
The pinion is a two-stage gear in which a first gear meshing with the first rack and a second gear meshing with the second rack are fixed to a concentric shaft, and the pitch of the second gear The circle diameter is twice the pitch circle diameter of the first gear,
Furthermore, said 1st rack is attached to the axial direction edge part of the said rolling element holder | retainer, The linear guide apparatus of Claim 2 characterized by the above-mentioned .

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