JP2007138977A - End cover mounting structure for telescopic shaft - Google Patents

Abstract

An inner hole of a hollow shaft 21 of a telescopic shaft 1 formed by spline fitting or serration fitting to an inner hole of a hollow shaft 21 to close the inner shaft 3 at the back in the insertion direction of the inner shaft 3. In the structure in which the end cover 5 is attached, the inner shaft 3 can be allowed to have a large diameter while securing a sufficient attachment strength and sealing performance while being relatively inexpensive.
A cylindrical surface 21b having a diameter larger than that of a female spline portion 21a of the hollow shaft 21 is provided on the inner side of the hollow shaft 21 in the insertion direction of the inner shaft 3. Further, the end cover 5 has a bottomed cylindrical shape, and its peripheral wall portion is single, and this peripheral wall portion is press-fitted to the large-diameter cylindrical surface 21 b of the hollow shaft 21 via the belt-like elastic ring 9.
[Selection] Figure 2

Description

  The present invention relates to an end cover mounting structure used for telescopic shafts such as a propeller shaft, a drive shaft, and an axle shaft provided in a vehicle such as an automobile.

  Conventionally, for example, the propeller shaft as described above has a configuration in which the inner shaft is spline-fitted or serrated-fitted into the inner hole of the hollow shaft, and the inner shaft is inserted into the inner hole of the hollow shaft at the back in the insertion direction of the inner shaft. An end cover for closing is attached.

  This end cover is used to prevent external leakage of lubricant such as grease applied to the spline fitting part or serration fitting part, and entry of external foreign matter (moisture, dust, etc.) to the fitting part. It is used.

  This end cover is usually manufactured into a bottomed cylindrical shape by drawing a metal plate, but when the peripheral wall portion of this end cover is directly press-fitted into the inner hole of the metal hollow shaft, From the relationship that the fitting length becomes long and the fitting between metals becomes fitting, it is not preferable in the following points.

  First, due to the metal fitting itself, the fitting surface is not sufficiently sealed. In addition, the tightness of the pressure fitting may cause the roundness of the end cover to be plastically deformed into a shape that undulates in the circumferential direction, even though the end cover has a small size. Is insufficient.

  Further, when the end cover is press-fitted and fitted, the outer peripheral edge of the open end of the end cover is rubbed against the inner peripheral surface of the inner hole of the hollow shaft, and there is a possibility of generating shavings. If this shaving powder enters the spline fitting portion or the serration fitting portion, it causes a problem in the sliding operation of both shafts.

  In this case, after mounting the end cover, clean the hollow shaft and inner shaft to remove the shavings, or deburr or chamfer the outer edge of the open end of the end cover to make it difficult to scrape the other party or itself Such measures are required, and the manufacturing cost is inevitably increased.

On the other hand, it is considered that a double cylinder structure is formed by concentrically folding the open end side of the end cover to the outer diameter side of the peripheral wall portion (see, for example, Patent Documents 1 and 2). In the case of such a double cylinder structure, it is difficult to manufacture the outer cylinder part and the inner cylinder part so that the outer cylinder part and the inner cylinder part are brought into close contact with each other. The thickness dimension from an inner peripheral surface to an outer cylinder part outer peripheral surface becomes large.
JP 2004-359100 A JP 20043606076 A

  In the above conventional example, just as in the case of a simple bottomed cylindrical end cover, it is only pointed out that the sealing performance of the fitting surface is insufficient from the relationship in which the metal is still fitted. In addition, processing the end cover into a double-cylinder structure itself is time-consuming and requires a reduction in productivity and an increase in manufacturing cost.

  Furthermore, in the case of an end cover having a double cylinder structure, it is difficult to reduce the thickness dimension from the inner peripheral surface of the inner cylinder part to the outer peripheral surface of the outer cylinder part. Will cause problems.

  In other words, if it is designed so that the inner end portion of the inner shaft enters the inside of the end cover in a state where the hollow shaft and the inner shaft of the telescopic shaft as described above are contracted to the minimum, the inner diameter dimension of the end cover is set to It is necessary to set the diameter equal to or larger than the circle diameter connecting each tooth tip of the female spline part. To that end, the circle connecting the inner peripheral surface of the end cover mounting part and each tooth tip of the female spline part in the hollow shaft The step with the diameter needs to be larger than the thickness dimension in the end cover of the double cylinder structure.

  For this reason, it is necessary to increase the thickness of the hollow shaft, which increases the weight and cost of the hollow shaft more than necessary. Moreover, when the outer diameter dimension of the hollow shaft is restricted, the circular diameter connecting each tooth tip of the female spline portion of the hollow shaft, that is, the outer diameter dimension of the inner shaft has to be reduced. Since the inner end portion of the inner shaft cannot be inserted inside the end cover when the hollow shaft and the inner shaft are contracted to the minimum, it is necessary to lengthen the entire length of the telescopic shaft and the bending rigidity of the telescopic shaft. There is concern that it may lead to a decline.

  An object of the present invention is to permit an increase in the diameter of an inner shaft while ensuring sufficient mounting strength and sealing performance in an end cover mounting structure for a telescopic shaft while being relatively inexpensive.

  The present invention provides an end for closing the inner shaft of the telescopic shaft formed by spline fitting or serration fitting to the inner shaft of the hollow shaft at the back side in the insertion direction of the inner shaft. A cover is attached, and a large-diameter cylindrical surface for mounting an end cover having a diameter larger than that of the female spline portion of the hollow shaft inner hole is provided in the inner hole of the hollow shaft on the inner side in the insertion direction of the inner shaft. The end cover has a cylindrical shape with a bottom, the peripheral wall portion is single, and the peripheral wall portion is press-fitted and fitted to the large-diameter cylindrical surface of the hollow shaft through a belt-like elastic ring. Yes.

  According to this configuration, since the belt-like elastic ring is interposed between the large-diameter cylindrical surface of the hollow shaft and the peripheral wall portion of the end cover in a state of being compressed and deformed by press-fitting, the end cover is attached to the hollow shaft. It is firmly positioned and fixed to the large-diameter cylindrical surface, and the band-shaped elastic ring makes close contact with the large-diameter cylindrical surface of the hollow shaft and the peripheral wall of the end cover, improving the sealing performance of each contact surface. To come.

  In addition, since the peripheral wall portion of the end cover is single, the manufacturing becomes easier than in the case of a double cylinder as in the conventional example, and the large-diameter cylindrical surface of the hollow shaft and the tooth splines of the female spline portion are respectively attached. Since the step with the connecting circle diameter can be made as small as possible, the thickness of the hollow shaft can be reduced, which can contribute to weight reduction and cost reduction. As the hollow shaft can be made thinner, the inner diameter of the end cover can be increased as much as possible without increasing the outer diameter of the hollow shaft. It becomes possible to respond.

  Further, the end cover is not directly press-fitted into the large-diameter cylindrical surface of the hollow shaft, and the belt-like elastic ring is press-fitted into the large-diameter cylindrical surface of the hollow shaft. As in the conventional example, which is press-fitted directly into the diameter cylindrical surface, it is not necessary to generate shaving powder. As a result, the edge processing of the end cover and the cleaning processing of the hollow shaft, the inner shaft, and the like as in the conventional example become unnecessary, and waste can be saved.

  Preferably, the inner diameter dimension of the peripheral wall portion of the end cover is equal to or larger than the circular diameter dimension connecting each tooth tip of the female spline portion of the hollow shaft.

  According to this configuration, it is possible to allow the inner end portion of the inner shaft to enter the inside of the end cover in a state where the hollow shaft and the inner shaft are contracted to the minimum. This makes it possible to shorten the overall length of the telescopic shaft and ensure sufficient bending rigidity of the telescopic shaft. Even if the maximum outer diameter dimension of the hollow shaft is restricted, it is not necessary to reduce the circular diameter connecting the tooth tips of the female spline portion of the hollow shaft, that is, the outer diameter dimension of the inner shaft.

  Preferably, the end cover is manufactured by drawing a metal plate, and an opening end thereof has a bent portion that protrudes radially outward and abuts the end surface of the belt-like elastic ring. Provided.

  According to this configuration, when the belt-shaped elastic ring attached to the outer periphery of the end cover is pressed in the mounting direction when the end cover is mounted, the pressing force is transmitted to the bent portion, so that the entire end cover is hollow. It will be pushed into the back of the large-diameter cylindrical surface of the shaft. Thereby, even if it is an end cover with a strip | belt-shaped elastic ring, the attachment can be performed now comparatively easily.

  In addition, since the bent portion is small enough to be caught by the belt-like elastic ring, the bending work can be easily dealt with at the time of drawing, and it is easier to manufacture than the conventional double-cylinder end cover. It becomes.

  According to the present invention, in the end cover mounting structure for the telescopic shaft, it is possible to allow an increase in the diameter of the inner shaft while ensuring sufficient mounting strength and sealing performance while being relatively inexpensive.

  Accordingly, the lubrication condition of the spline fitting portion or the serration fitting portion of the telescopic shaft can be kept good for a long period of time, which can greatly contribute to the improvement of reliability such as the operational smoothness and durability of the telescopic shaft.

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show an embodiment of the present invention. A propeller shaft provided in a vehicle such as an automobile is taken as an example of the telescopic shaft to which the end cover mounting structure according to the present invention is applied.

  Therefore, prior to the description of the end cover mounting structure according to the present invention, the basic configuration of the propeller shaft as the telescopic shaft will be described.

  As shown in FIG. 1, the propeller shaft 1 is basically the same as a generally known configuration. In short, the propeller shaft 1 is spline-fitted in the center hole (inner hole) of the outer shaft 2 so that the inner shaft 3 can be displaced in the axial direction. The universal joints 4 and 4 are respectively attached to the outer end of the outer shaft 2 and the outer end of the inner shaft 3.

  The outer shaft 2 has a two-piece structure in which a small-diameter hollow shaft 21 and a large-diameter hollow shaft 21b are connected in the axial direction. The small-diameter hollow shaft 21 corresponds to the hollow shaft described in the claims. However, the outer shaft 2 may have a one-piece structure, and in this case, the one-piece outer shaft 2 itself corresponds to the hollow shaft described in the claims.

  Both the outer shaft 2 and the inner shaft 3 are formed hollow, and spline (or serration) portions 21 a and 31 are provided on the inner peripheral surface of the small-diameter hollow shaft 21 and the outer peripheral surface of the inner shaft 3, respectively. Is provided.

  Since the spline portion 21a of the small-diameter hollow shaft 21 is formed on the inner peripheral surface, hereinafter, it will be referred to as a female spline portion, and the spline portion 31 of the inner shaft 3 is formed on the outer peripheral surface. Hereinafter, it will be referred to as a male spline part.

  The universal joint 4 is generally a known cruciform joint, and includes a cruciform shaft 41 and two yokes 42 and 43.

  The first yokes 42, 42 are integrally attached to the outer end of the large-diameter hollow shaft 22 and the outer end of the inner shaft 3 in the outer shaft 2, and the second yokes 43, 43 are connected to the propeller shaft. 1 is connected to a shaft member or the like (not shown) to be connected.

  Both yokes 42 and 43 have a shape in which projecting pieces are provided at positions facing each other by 180 degrees on the circumference on one end side of the cylindrical body.

  In the yokes 42 and 43 having such a shape, if the inner holes of the outer shaft 2 and the inner shaft 3 are not closed while passing through in the axial direction, the spline fitting portions of both the shafts 2 and 3 enter there. There is a possibility that a lubricant such as grease to be applied leaks to the outside, or foreign matter (moisture, dust, etc.) enters the spline fitting portion of both shafts 2 and 3 from the outside.

  In order to prevent such external leakage of lubricant and entry of foreign matter, the inner open end of the spline fitting portion is the end cover 5 and the end plate 6, and the outer open end of the spline fitting portion is the protective cover 7. Each is sealed.

  The end cover 5 is attached to the inner hole of the outer shaft 2 on the back side in the insertion direction of the inner shaft 3 (the inner end side of the small-diameter hollow shaft 21) so as to close the end cover 5, but the mounting structure will be described in detail later. Explained.

  The end plate 6 is attached to the inner end side opening of the hollow inner shaft 3 so as to close the end plate 6. The end plate 6 has a disc shape and is provided with a ring-shaped portion on the outer periphery thereof. The ring-shaped portion is press-fitted to the large-diameter inner peripheral surface of the inner end side opening of the inner shaft 3. ing.

  In this embodiment, since the inner shaft 3 is made hollow for weight reduction, the end plate 6 is attached to the inner end side of the inner plate 3 in a lid shape so that the inner end side of the inner hole of the inner shaft 3 is attached. The opening is closed. However, the inner shaft 3 can be solid, and in this case, the end plate 6 is not necessary.

  The protective cover 7 has a cylindrical shape whose one end is fixed to the enlarged diameter portion 32 on the outer end side of the inner shaft 3 by an appropriate method so as to surround the outer peripheral surface of the small-diameter hollow shaft 21 in the outer shaft 2 in a non-contact manner. A seal ring 8 made of a pipe and in contact with the outer peripheral surface of the small-diameter hollow shaft 21 in the outer shaft 2 to form a sealing portion is mounted on the free end side.

  The seal ring 8 is made of a material appropriately selected from generally known various seal rings.

  Such a protective cover 7 covers the inner peripheral surface of the protective cover 7 with a seal ring 8 attached to its free end in a state where the spline fitting portion between the small-diameter hollow shaft 21 and the inner shaft 3 in the outer shaft 2 is covered. And the opening of the opposed annular space between the outer shaft 2 and the outer peripheral surface of the small-diameter hollow shaft 21 is closed.

  Next, the attachment structure of the end cover 5 as a characteristic part of the present invention will be described.

  First, the end cover 5 is manufactured into a bottomed cylindrical shape by, for example, drawing a metal plate, the peripheral wall portion is single, and the opening end is bent slightly outward in the radial direction. A bent portion 51 is provided.

  Before the end cover 5 is attached to the small-diameter hollow shaft 21 in the outer shaft 2, a belt-like elastic ring 9 is fitted on the opening end side of the peripheral wall portion of the end cover 5.

  As shown in the drawing, the belt-like elastic ring 9 is flat in the radial direction and has a cylindrical shape, and a material that can be appropriately expanded and contracted in the radial direction and the axial direction is selected.

  As for the material of the belt-like elastic ring 9, for example, an appropriate rubber (nitrile rubber, fluorine rubber, chloroprene rubber generally used for a known seal ring) or an appropriate resin (thermoplastic polyester elastomer, etc.) can do.

  On the other hand, on the inner end side of the small-diameter hollow shaft 21 in the outer shaft 2 (the inner side of the inner shaft 3 in the insertion direction of the inner shaft 3 in the inner hole of the outer shaft 2) is a circle connecting the tooth tips of the female spline portion 21a of the small-diameter hollow shaft 21. A large-diameter cylindrical surface 21b having an inner diameter R2 larger than the diameter R1 is provided. The end cover 5 is attached to the large-diameter cylindrical surface 21b via the belt-like elastic ring 9.

  The outer diameter R3 of the end cover 5 is set smaller than the inner diameter R2 of the large-diameter cylindrical surface 21b so that a predetermined annular gap is formed between the end cover 5 and the large-diameter cylindrical surface 21b. Further, the inner diameter R4 of the end cover 5 is set to be the same as or slightly larger than the circular diameter R1 connecting the tooth tips of the female spline portion 21a.

  And the attachment procedure of the end cover 5 is demonstrated with reference to FIG. 5 and FIG.

  First, as shown by the arrows in FIG. 5, the belt-like elastic ring 9 is fitted on the outer periphery of the peripheral wall portion of the end cover 5 by press fitting. At this time, by pressing the front end surface in the press-fitting direction of the band-shaped elastic ring 9, the end surface in the press-fitting direction of the band-shaped elastic ring 9 is brought into contact with the radially rising wall surface in the bent portion 51 on the opening end side of the end cover 5. Press fit until you let it go.

  As a result, the belt-like elastic ring 9 is fitted to a predetermined position on the end cover 5 in a state where the diameter is slightly elastically expanded, so that the belt-like elastic ring 9 is fastened to the peripheral wall portion of the end cover 5 by the elastic restoring force. At the same time, the belt-like elastic ring 9 cannot be easily detached while being positioned in the axial direction on the radially rising wall surface in the bent portion 51.

  Thus, the end cover 5 to which the belt-like elastic ring 9 is attached is fitted into the large-diameter cylindrical surface 21b of the small-diameter hollow shaft 21 in the outer shaft 2 by press-fitting as shown by the arrows in FIG. At this time, the front end surface in the press-fitting direction of the belt-shaped elastic ring 9 is pressed with an appropriate jig, but this pressing force is transmitted to the bent portion 51 of the end cover 5 through the band-shaped elastic ring 9, so that the end The entire cover 5 is pushed into the back.

  Thereby, the belt-like elastic ring 9 is elastically compressed and deformed between the outer peripheral surface of the peripheral wall portion of the end cover 5 and the inner peripheral surface of the large-diameter cylindrical surface 21b of the small-diameter hollow shaft 21, as shown in FIG. Intervened in state. Therefore, the outer peripheral surface of the belt-shaped elastic ring 9 is in close contact with the large-diameter cylindrical surface 21b of the small-diameter hollow shaft 21, and the inner peripheral surface of the belt-shaped elastic ring 9 is in close contact with the outer peripheral surface of the peripheral wall portion of the end cover 5. Therefore, both the fitting surfaces are sealed, and the end cover 5 is firmly attached so as not to come out.

  Thus, after attaching the end cover 5 to the small-diameter hollow shaft 21 in the outer shaft 2, the inner end of the small-diameter hollow shaft 21 and the inner end of the large-diameter hollow shaft 22 are connected.

  This connection can be performed by an appropriate method, but in this embodiment, for example, a friction welding method is used. However, it is not limited to the friction welding method, it is a welding that applies heat from the outside, such as electric welding or gas welding, or a form in which one end is crimped to the other end and fixed, Or a flange connection.

  Here, since the friction welding method is generally known, a detailed description of the method is omitted, but in short, the inner end surface of the small-diameter hollow shaft 21 and the inner end surface of the large-diameter hollow shaft 22 are set to a predetermined pressure. Rotate at a relatively high speed in the pressed state.

  The butt portion is melted by the frictional heat generated thereby, and welded by solid phase diffusion.

  In this welding process, the butted portion is melted, and as shown in FIG. 2, it protrudes inward and outward in the radial direction and the ring-shaped protrusions 11 and 12 are formed.

  At this time, by controlling the protrusion allowance of the inner ring-shaped protrusion 11 as much as possible, the inner diameter dimension R5 of the ring-shaped protrusion 11 is managed to be smaller than the outer diameter dimension R3 of the end cover 5. . As a result, the inner ring-shaped protrusion 11 functions as a stopper for preventing the end cover 5 from slipping out of the small diameter hollow shaft 21 outward in the axial direction.

  As described above, since the belt-like elastic ring 9 is interposed between the large-diameter cylindrical surface 21b of the small-diameter hollow shaft 21 and the peripheral wall portion of the end cover 5 in a state of being compressed and deformed by press-fit tightening, The cover 5 is firmly positioned and fixed to the large-diameter cylindrical surface 21b of the small-diameter hollow shaft 21, and the belt-like elastic rings 9 are respectively attached to the large-diameter cylindrical surface 21b of the small-diameter hollow shaft 21 and the peripheral wall portion of the end cover 5. Since it contacts closely, the sealing performance of each contact surface comes to improve.

  In addition, since the peripheral wall portion of the end cover 5 is single, the manufacturing is easier than in the case of a double cylinder as in the conventional example, and the large-diameter cylindrical surface 21b and the female spline portion in the small-diameter hollow shaft 21 are provided. It is possible to make the step difference from the circle diameter connecting each tooth tip of 21a as small as possible.

  This makes it possible to reduce the thickness of the small-diameter hollow shaft 21 and contribute to weight reduction and acquisition cost reduction. Since the small-diameter hollow shaft 21 can be made thin as described above, the inner diameter of the end cover 5 can be increased as much as possible without greatly increasing the outer diameter of the small-diameter hollow shaft 21. 3 can be made to have a larger diameter.

  Further, since the inner diameter R4 of the end cover 5 is set to be equal to or slightly larger than the circular diameter R1 connecting the teeth of the female spline portion 21a, the small-diameter hollow shaft 21 and the inner shaft 3 are reduced to the minimum. In this state, the inner end portion of the inner shaft 3 can be inserted inside the end cover 5, the overall length of the drive shaft 1 can be shortened, and sufficient bending rigidity of the drive shaft 1 can be obtained. It becomes possible to secure. Even if the maximum outer diameter of the small-diameter hollow shaft 21 in the outer shaft 2 is restricted, the diameter of the circle connecting the tooth tips of the female spline portion 21a of the small-diameter hollow shaft 21, that is, the outer diameter of the inner shaft 3 is reduced. You do n’t have to.

  Further, since the end cover 5 is not directly press-fitted into the large-diameter cylindrical surface 21b of the small-diameter hollow shaft 21, the belt-like elastic ring 9 is press-fitted into the large-diameter cylindrical surface 21b of the small-diameter hollow shaft 21. As in the conventional example in which the end cover 5 is directly press-fitted into the large-diameter cylindrical surface 21 b of the small-diameter hollow shaft 21, it is not necessary to generate shaving powder. As a result, it is possible to eliminate waste, such as eliminating the edge processing of the end cover 5 and the cleaning processing of the small-diameter hollow shaft 21 and the inner shaft 3 as in the conventional example.

  In addition, since the belt-like elastic ring 9 has a belt-like shape, the press-fitting allowance is reduced after the radial thickness is reduced as compared with the case where an O-ring or the like is simply interposed between the fitting surfaces of the end cover 5 and the small-diameter hollow shaft 21. Can be secured for a relatively long time, and the attachment strength of the end cover 5 and the sealing performance of the fitting surface are improved.

  Hereinafter, other embodiments of the present invention will be described.

  (1) In the above embodiment, the telescopic shaft is the propeller shaft 1 used between the transmission of the rear-wheel drive vehicle and the rear differential. For example, the rear shaft used between the transfer of the four-wheel drive vehicle and the rear differential is used. The present invention can also be applied to a propeller shaft, a front propeller shaft used between a transfer and a front differential gear, or various drive shafts and axle shafts of a vehicle, and other telescopic shafts used in the field of machine tools. It is.

  (2) In the above-described embodiment, the small-diameter hollow shaft 21, the large-diameter hollow shaft 22, the inner shaft 3, and the end cover 5 in the outer shaft 2 are not limited to being made of metal but may be made of resin.

However, in the case of using resin, it is preferable to set the tightening margin so as not to cause a crack or the like when the small-diameter hollow shaft 21 and the end cover 5 are press-fitted in the outer shaft 2.

It is a side view including the partial cross section of the propeller shaft to which one Embodiment of the end cover attachment structure of this invention is applied. It is a figure which expands and shows the end cover periphery of FIG. FIG. 3 is a cross-sectional view taken along line (3)-(3) in FIG. 2. It is a perspective view which shows the state which removed the end cover of FIG. It is explanatory drawing which shows the mode of the preparations at the time of attaching the end cover of FIG. 1 to a small diameter hollow shaft. It is a figure which shows a mode at the time of attaching the end cover of FIG. 5 to a small diameter hollow shaft.

Explanation of symbols

1 Propeller shaft
2 Outer shaft
21 Small-diameter hollow shaft constituting the outer shaft
21a Female spline part of small diameter hollow shaft
21b Large diameter cylindrical surface of small diameter hollow shaft
22 Large-diameter hollow shaft constituting the outer shaft
3 Inner shaft
31 Male spline part of inner shaft
4 Universal joint
5 End cover
51 End cover bend
9 Strip elastic ring

Claims (3)

At the inner hole of the hollow shaft of the telescopic shaft formed by spline fitting or serration fitting the inner shaft to the inner hole of the hollow shaft, an end cover for closing the inner shaft was attached to the inner side of the inner shaft in the insertion direction. Structure,
A large-diameter cylindrical surface for attaching an end cover having a larger diameter than the female spline portion of the hollow shaft inner hole is provided on the inner shaft insertion hole side in the hollow shaft inner hole.
The end cover has a bottomed cylindrical shape, its peripheral wall portion is single, and this peripheral wall portion is press-fitted to the large-diameter cylindrical surface of the hollow shaft through a belt-like elastic ring. Mounting structure for shaft end cover.   2. The structure for attaching an end cover for a telescopic shaft according to claim 1, wherein an inner diameter of the peripheral wall portion of the end cover is equal to or greater than a circular diameter connecting each tooth tip of the female spline portion of the hollow shaft.   3. The end cover according to claim 1, wherein the end cover is manufactured by drawing a metal plate, and an end of the belt-shaped elastic ring projects radially outward at an opening end thereof. A structure for attaching an end cover for a telescopic shaft, wherein a bent portion is provided.

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