JP2010084893A - Connection structure and steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connection structure capable of preventing a pinion shaft 31 and a joint yoke 21 from being positionally displaced in an axial direction when connecting them. <P>SOLUTION: A serration groove 12 is formed in the outer peripheral surface of a pinion shaft 31. A positioning member 1 for positioning a relative position in a rotating direction and axial direction of a joint yoke 21 with respect to the pinion shaft 31 contains a ring part 2 in which a serration protrusion 6 externally suitable for the serration groove 12 is formed in the inner peripheral surface and on which the joint yoke 21 abuts from the axial direction. The serration protrusion 6 of the ring part 2 abuts on the groove end surface 13 of the serration groove 12 so as to be taken as a stopper part for positionally controlling the ring part 2 in the axial direction with respect to the pinion shaft 31. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a connection structure between a shaft and a joint member, and a steering device mounted on an automobile and using the connection structure.

  For example, an automobile steering device includes a rack and pinion type steering gear unit for steering a wheel, a steering shaft connected to a steering wheel, and a pinion shaft included in the steering shaft and the steering gear unit. An intermediate shaft (intermediate shaft) is provided, and the intermediate shaft 40 and the pinion shaft 41 are connected via a universal joint 42 as shown in FIG. The universal joint 42 has a cross shaft 43 and a pair of joint yokes (joint members) 44, 45. One joint yoke 44 is connected to the lower end portion of the intermediate shaft 40, and the other joint yoke 45 is a pinion shaft 41. And serrations 46 (see, for example, Patent Document 1).

  In assembling such a steering device, the pinion shaft 41 of the steering gear unit and the joint yoke 45 are rotated in the rotational direction so that the straight traveling state of the wheel by the steering gear unit matches the neutral state of the shaft on the steering wheel side. Need to be positioned (aligned) and serrated. For this purpose, a positioning member (positioning clip) 47 attached to the pinion shaft 41 is used.

Japanese Patent Laying-Open No. 2005-280564 (see FIG. 11)

  The conventional positioning member 47 includes a ring portion 48 engaged with the serration 46 of the pinion shaft 41, a protruding piece (arm portion) 49 that protrudes radially outward from the pinion shaft 41, and the pinion shaft 41. And an engaging portion 50 engaged with the distal end portion. The projecting piece 49 engages with an axial slit 51 formed in the joint yoke 45, whereby the pinion shaft 41 and the joint yoke 45 are positioned in the rotational direction. Then, the axial position of the joint yoke 45 is aligned with the pinion shaft 41 by the lower end of the joint yoke 45 coming into contact with the ring portion 48 from the axial direction.

  However, since the positioning member 47 is only restricted in movement in the axial direction with respect to the pinion shaft 41 by the engaging portion 50 engaged with the tip end portion of the pinion shaft 41, the positioning member 47 is connected to the pinion shaft 41 with a universal joint. When the intermediate shaft 40 and the steering shaft (not shown) are attached via 42, if an axial load acts on the ring portion 48 of the positioning member 47 by the weights of the universal joint 42, the intermediate shaft 40 and the steering shaft, the ring portion The positioning member 47 is deformed so that 48 is separated from the engaging portion 50 in the axial direction, and the joint yoke 45 may be displaced in the axial direction (in the arrow Y direction) with respect to the pinion shaft 41. In this case, the axial positions of the bolt insertion holes 45 a formed in the joint yoke 45 and the bolt insertion grooves 45 b of the pinion shaft 41 do not match, and the joint yoke 45 and the pinion shaft 41 are connected by the bolts 52. There is a possibility that the work for securing the stopper may be difficult, or the bolt 52 may not be completely attached, resulting in poor connection.

  Accordingly, the present invention provides a connection structure capable of preventing the shaft and the joint member from being displaced in the axial direction when connecting the shaft and the joint member, and a steering device using the connection structure. With the goal.

  The connection structure of the present invention includes a shaft, a joint member that is serration-coupled coaxially with the shaft, and a relative position in the rotational direction and the axial direction of the joint member with respect to the shaft. A connecting structure including a positioning member attached in advance, and located on the outer peripheral surface of the shaft, on a groove bottom located on the radially inner side of the outer peripheral surface of the shaft, and in an axially intermediate portion of the shaft A serration groove having a groove end surface is formed, and the positioning member has a serration protrusion that is fitted on the serration groove on an inner peripheral surface, and a ring portion on which the joint member abuts in the axial direction. In addition, the serration protrusion of the ring portion comes into contact with the groove end surface so that the ring portion is axially moved with respect to the shaft. Characterized in that it has become the stopper portion to location regulations.

  According to the present invention, when the joint member is serrated and connected to the shaft coaxially, the joint member is in contact with the ring portion from the axial direction, and the pressing force when the contact is made is large. Even so, the stopper portion (first stopper portion) formed on the inner peripheral surface of the ring portion abuts against the groove end surface of the serration groove of the shaft, so that the ring portion is axially moved with respect to the shaft. The position is restricted. For this reason, it can prevent that a joint member moves to an axial direction with respect to a shaft by the said pushing force. As a result, the joint member is positioned in the axial direction with respect to the shaft, and the work of securing and fixing the shaft and the joint member with a fastening member such as a bolt and nut becomes easy.

Further, a peripheral protrusion is formed on the outer peripheral surface of the shaft, and a second stopper portion that contacts the peripheral protrusion at the same time that the serration protrusion contacts the groove end surface is formed on the ring portion of the positioning member. Preferably it is formed.
In this case, the positioning function in the axial direction with respect to the shaft can be strengthened by the second stopper portion coming into contact with the peripheral protrusion on the outer peripheral surface of the shaft at the same time that the serration protrusion comes into contact with the groove end surface.

In addition, the positioning member has a protruding piece that protrudes in an outer radial direction and an axial direction of the ring portion, and the serrated protruding portion contacts the groove end surface at the same time as the protruding piece abuts on the end surface of the shaft. It is preferable that the 3rd stopper part which touches is connected.
In this case, the positioning function in the axial direction with respect to the shaft can be enhanced by the third stopper portion being in contact with the end surface of the shaft at the same time as the serration protrusion is in contact with the groove end surface.

  The steering device of the present invention includes a steering gear unit having a pinion shaft for steering the wheel, a transmission shaft for transmitting rotation of the steering wheel to the pinion shaft, the pinion shaft and the transmission shaft. And the pinion shaft and the joint member are serration-coupled coaxially by the connection structure. Thus, since the connection structure is used, the assembly of the steering device is facilitated.

  According to the present invention, since the stopper portion of the ring portion of the positioning member abuts the groove end surface of the serration groove of the shaft, the joint member is positioned in the axial direction with respect to the shaft. For example, the operation of securing the joint member and the joint member with a fastening member such as a bolt and nut can be facilitated, and the shaft and the joint member can be quickly and accurately connected.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall schematic view showing an embodiment of a steering apparatus of the present invention. The steering device includes a steering gear unit 32 having a pinion shaft 31 for steering a wheel (not shown), and a transmission shaft for transmitting rotation of the steering wheel 33 to the pinion shaft 31. . The transmission shaft has a steering shaft 34 and an intermediate shaft 35 interposed between the steering shaft 34 and the pinion shaft 31. The steering shaft 34 and the intermediate shaft 35 are connected via a first universal joint 36, and the intermediate shaft 35 and the pinion shaft 31 are connected via a second universal joint 37.

FIG. 2 is a perspective view of a main part of the steering device, and FIG. 3 is a perspective view of the main part showing an exploded state thereof. The pinion shaft 31 protrudes upward from the gear box 32a of the steering gear unit 32, and serrations 11a and 11b are formed vertically on the input shaft portion, which is a tip portion, with an annular groove 11c having a circular arc cross section. (See FIG. 3).
More specifically, on the outer peripheral surface of the pinion shaft 31 (see FIG. 6B), the groove bottom 14 positioned on the inner side of the outer peripheral finish surface 31b of the pinion shaft 31 and the axially intermediate portion of the pinion shaft 31 A serration groove 12 having a groove end face 13 located at the position is formed.

  2 and 3, the second universal joint 37 has a cross shaft 38 and a pair of joint yokes 21 and 22, and one joint yoke 22 is connected to the lower end of the intermediate shaft 35, and the other The joint yoke 21 is connected to the pinion shaft 31 by the serrations 11a and 11b so that torque can be transmitted.

  The connection structure of the present invention used in this steering device is a structure between the pinion shaft 31 and the first joint yoke 21. That is, this connection structure includes a pinion shaft (shaft) 31 in which the serrations 11a and 11b are formed on the outer periphery, and a joint yoke 21 that is serrated and connected to the pinion shaft 31 coaxially so as to transmit torque. (Joint member) and a positioning member 1 for positioning the relative position in the rotational direction and the axial direction of the joint yoke 21 with respect to the pinion shaft 31. The positioning member 1 is a member attached in advance to the pinion shaft 31 before connecting the joint yoke 21.

  The joint yoke 21 has a base portion 23 having an axial slit 28 and a pair of arm portions 24a and 24b branched from the base portion 23 and extending in the axial direction. A serration hole 25 that engages with the serrations 11 a and 11 b is formed inside the base portion 23. A through hole 26 is formed in the base 23 so as to cross the slit 28. The base 23 can be fastened and fixed to the pinion shaft 31 by inserting a bolt 27 through the through hole 26 and tightening a portion where a slit 28 is formed by a nut (not shown). Further, a part of the bolt 27 is engaged with the annular groove 11 c (see FIG. 3) of the pinion shaft 31, and the joint yoke 21 is prevented from coming off in the axial direction with respect to the pinion shaft 31.

  FIG. 4 is a perspective view of the positioning member 1, and FIG. 5 is a cross-sectional view showing a state where the positioning member 1 is attached to the input shaft portion of the pinion shaft 31. In FIG. 5, the tip surface of the pinion shaft 31 is provided with a protruding portion 31 a that protrudes in the axial direction. In addition, this protrusion part 31a consists of the front-end | tip part of the torsion bar which has penetrated the inside of the pinion shaft 31. FIG.

  The positioning member 1 has an annular ring portion 2 and a plate-like protruding piece 3. In this embodiment, the positioning member 1 further includes an annular engaging portion 4. The ring portion 2 is formed with serrations 5 that engage with the serrations 11b on a part of the inner peripheral surface (almost half of the engagement portion 4 side). That is, the serration protrusion 6 that fits into the serration groove 12 is formed on the inner peripheral surface of the ring portion 2. The remaining portion of the inner peripheral surface of the ring portion 2 is a smooth circumferential surface 18. Further, the lower surface of the joint yoke 21 abuts on the upper surface of the ring portion 2 from the axial direction.

  4 and 5, the protruding piece 3 is formed so as to protrude from a part of the ring portion 2 in the axial direction and the radially outward direction, and has a linear plate shape. One end portion (lower end portion) of the protruding piece 3 and a part of the ring portion 2 are connected. Moreover, the engaging part 4 is connected with the other end part (upper end part) of the protrusion piece 3, and the ring part 2, the protrusion piece 3, and the engaging part 4 are comprised integrally.

In a state where the positioning member 1 is attached to the pinion shaft 31, the protruding piece 3 is in a state of protruding from the pinion shaft 31 in the radially outward direction. As shown in FIG. 2, the protruding piece 3 engages with the axial slit 28 of the joint yoke 21. In addition, a notch recess 3 a for inserting the bolt 27 for tightening is formed in the inner central portion of the protruding piece 3.
The engaging portion 4 is fitted on the protrusion 31a at the tip of the pinion shaft 31 (see FIG. 5). The engaging portion 4 has a function as a third stopper portion 9 described later.

  In the above connection structure, a connection method for connecting the joint yoke 21 to the pinion shaft 31 will be described. As shown in FIG. 3, the positioning member 1 is attached to the tip of the pinion shaft 31, the ring portion 2 of the positioning member 1 is engaged with the serration 11b, and the engaging portion 4 is engaged with the protrusion 31a. State.

  The positioning member 1 is attached to the pinion shaft 31 by positioning (positioning) the positioning member 1 in the rotational direction with respect to the distal end portion of the pinion shaft 31. That is, the positioning member 1 is mounted in a state where the steering gear unit 32 of FIG. 1 is set so that the wheel (not shown) is in a straight traveling state, and in this state, the protruding piece 3 is defined in the rotational direction. The ring portion 2 is coupled to the serration 11b of the pinion shaft 31 by performing alignment so as to face the direction.

  Then, the joint yoke 21 is assembled to the pinion shaft 31 on which the positioning member 1 is mounted. This assembly is performed in a state where the steering wheel 33, the steering shaft 34, and the intermediate shaft 35 are set so as to be in a neutral state (straight forward state). In this state, the slit 28 of the joint yoke 21 is formed in the base 23 so that the position of the protruding piece 3 facing the specified direction and the rotational direction coincide.

  Therefore, by pushing the joint yoke 21 axially into the pinion shaft 31, as shown in FIG. 2, the projecting piece 3 is guided in the slit 28, and the serration hole 25 of the joint yoke 21 As the serrations 11a and 11b of the pinion shaft 31 are coupled, the pinion shaft 31 and the joint yoke 21 are coupled in a state of being positioned in the rotational direction. That is, the pinion shaft 31 and the joint yoke 21 are positioned in the rotational direction by the engagement between the protruding piece 3 of the positioning member 1 and the slit 28 of the joint yoke 21.

  Further, the front end surface of the joint yoke 21 (the lower surface of the base portion 23) abuts on the annular one end surface 2 a (upper surface) of the ring portion 2 of the positioning member 1, and the joint yoke 21 is placed on the one end surface 2 a of the ring portion 2. It will be on the state. That is, the joint yoke 21 is in a state of pushing the ring portion 2 downward in the axial direction by its own weight. In this state, in FIG. 3, the annular groove 11 c formed in the pinion shaft 31, the through hole 26 formed in the joint yoke 21, and the notch recess 3 a of the protruding piece 3 of the positioning member 1 are It is necessary to match the same straight line. For this purpose, the positioning member 1 has a stopper portion for restricting the position of the ring portion 2 on which the joint yoke 21 is placed with respect to the pinion shaft 31 in the axial direction.

The stopper portion will be described. 6A shows an enlarged cross-section of a part of the ring portion 2 of the positioning member 1, and FIG. 6B shows an enlarged view showing a portion (attachment portion) of the pinion shaft 31 to which the ring portion 2 is attached. It is. FIG. 7 is an explanatory view showing a state in which the ring portion 2 is attached to the attachment portion.
As shown in FIG. 6B, a groove end face 13 is formed at the base end in the groove longitudinal direction of the serration groove 12 of the serration 11b on the base side of the pinion shaft 31. The groove end surface 13 has a shape that expands from the groove bottom 14 of the serration groove 12 to the outer peripheral finished surface 31 b of the pinion shaft 31. The cross-sectional shape of the groove end surface 13 is a smooth arc shape from the groove bottom 14 toward the outer peripheral finished surface 31 b of the pinion shaft 31.

  And the ring part 2 of the positioning member 1 has the 1st stopper part 7 contact | abutted to the said groove end surface 13 from an axial direction. In FIG. 6A, the serration projection 6 (the end surface in the axial direction of the serration projection 6) formed on the inner peripheral surface of the ring portion 2 abuts on the groove end surface 13, so that the pinion shaft 31 On the other hand, it is a first stopper portion 7 that restricts the position of the ring portion 2 in the axial direction.

  In order to form the first stopper portion 7 on the inner peripheral surface of the ring portion 2, the serration protrusion 6 is not formed over the entire length in the axial direction on the inner peripheral surface of the ring portion 2. It is formed between the axial end portion 15 and the midway portion 16 (upper side in FIG. 6A). And from the middle part 16 to the axial direction other end part 17 is a smooth circumferential surface 18 parallel to the center line of the ring part 2. The shape of the end face in the axial direction of the serration protrusion 6 is the same shape as the groove end face 13 and has a smooth arc shape.

  As described above, as shown in FIG. 7, the first stopper portion 7 provided on the inner peripheral surface of the ring portion 2 comes into contact with the groove end surface 13 of the serration groove 12 of the pinion shaft 31 from the axial direction. Thus, the position of the ring portion 2 can be restricted with respect to the pinion shaft 31 in the axially lower side (the pushing direction of the joint yoke 21). Therefore, when the joint yoke 21 is serrated to the pinion shaft 31, the joint yoke 21 pushes the ring portion 2 of the positioning member 1 downward in the axial direction, and even if the pushing force increases, the ring portion 2 is regulated in the axial direction with respect to the pinion shaft 31, it is possible to prevent the joint yoke 21 from moving in the axial direction with respect to the pinion shaft 31 by the pressing force.

  Therefore, the joint yoke 21 is positioned in the axial direction with respect to the pinion shaft 31 (see FIG. 3), the annular groove 11c of the pinion shaft 31, the through hole 26 of the joint yoke 21, and the protruding piece. The three notch recesses 3a can be made to coincide with each other. For this reason, the bolts 27 can be easily inserted into the through holes 26 and the like, and the pinion shaft 31 and the joint yoke 21 are secured to the bolts 27 by tightening nuts (not shown). Work becomes easy. As a result, the pinion shaft 31 and the joint yoke 21 can be connected quickly and accurately.

  Further, in FIG. 6B, a circumferential protrusion 39 is formed on the outer peripheral surface of the pinion shaft 31. More specifically, on the base side (lower side) in the axial direction from the serration 11b, a circumferential ridge 39 that protrudes radially outward from the serration 11b and is formed in the rotational direction is formed. The circumferential protrusion 39 is formed continuously in the rotational direction and has an annular shape, and is formed away from the groove end surface 13 in the axial direction. A taper surface 39a having a diameter increasing toward the base side is formed on the distal end side of the pinion shaft 31 in the circumferential protrusion 39.

  In FIG. 6A, the positioning member 1 has a second stopper portion 8 that restricts the position of the ring portion 2 relative to the pinion shaft 31 in the axial direction. The second stopper portion 8 is formed at the lower end portion in the axial direction of the ring portion 2, and at the axial position where the serration projection 6 abuts on the groove end surface 13 and at the same time abuts on the circumferential protrusion 39. Is provided.

  The second stopper portion 8 is formed of a tapered surface formed by expanding the diameter from the other axial end portion 17 of the inner peripheral surface of the ring portion 2 to the other end surface (lower surface) 2b of the ring portion 2. The second stopper portion (tapered surface) 8 has the same shape as the tapered surface 39a of the circumferential ridge 39 (FIG. 6B), and as shown in FIG. It contacts to the taper surface 39a from the axial direction.

  Thus, even if the joint yoke 21 strongly pushes the ring part 2 downward in the axial direction by restricting the position of the ring part 2 in the axial direction with respect to the pinion shaft 31 by the second stopper part 8, the first The joint yoke 21 can be prevented from moving axially downward with respect to the pinion shaft 31 in cooperation with the stopper portion 7. That is, the second stopper portion 8 can reinforce the axial positioning function of the joint yoke 21 with respect to the pinion shaft 31.

  Further, in FIG. 5, the positioning member 1 has a third stopper portion 9 for restricting the position of the ring portion 2 relative to the pinion shaft 31 in the axial direction. The third stopper portion 9 includes the engagement portion 4, and the serration projection 6 abuts against the groove end surface 13, and at the same time, the engagement portion 4 is provided at the tip of the pinion shaft 31. And the engaging portion 4 comes into contact with the tip surface of the pinion shaft 31. By engaging the third stopper portion 9 with the tip of the pinion shaft 31, the joint yoke 21 is axially moved relative to the pinion shaft 31 in cooperation with the first stopper portion 7 and the second stopper 8. It can be prevented from moving downward. That is, the third stopper portion 9 can strengthen the axial positioning function of the joint yoke 21 with respect to the pinion shaft 31.

  The conventional positioning member 47 shown in FIG. 8 also has an engaging portion 50 engaged with the tip of the pinion shaft 41. However, when the joint yoke 45 is serrated and connected to the pinion shaft 41, the conventional positioning member 47 shown in FIG. When the joint yoke 45 pushes the ring portion 48 of the positioning member 47 downward in the axial direction due to its own weight or the like, and the pushing force increases, the positioning member 47 is deformed so that the ring portion 48 is separated from the engaging portion 50 in the axial direction. The joint yoke 45 may be displaced in the axial direction (in the arrow Y direction) with respect to the pinion shaft 41. That is, in order to restrict the position of the ring portion 48 of the positioning member 47 to the pinion shaft 31 in the axial direction, the engagement portion 50 alone is not sufficient.

Therefore, although not shown in the conventional configuration, a concave groove is formed on the base side of the pinion shaft relative to the serration, an annular protrusion is formed in the ring portion of the positioning member, and the protrusion is fitted into the concave groove. A configuration that allows the However, in this case, since the concave circumferential groove is formed on the pinion shaft, the portion becomes thin, which may be a weak point of the pinion shaft that transmits torque.
However, according to the form shown in FIG. 7, the base portion side of the pinion shaft 31 that is the portion that transmits torque is the same outer diameter as the outer diameter of the serration 11 b or the outer diameter of the serration 11 b. Since the diameter is larger than the above, it does not have the above-mentioned weak points. That is, according to the form of FIG. 7, the pinion shaft 31 is not thin and has an advantageous structure in terms of strength.

  Further, the connection structure and the steering device of the present invention are not limited to the illustrated forms, and may be other forms within the scope of the present invention. In the illustrated embodiment, the case where the coupling structure is used in the steering device has been described. However, the present invention can be applied to a device other than the steering device. Moreover, although the joint member connected with a shaft was demonstrated as the joint yoke 21 of the universal joint 37 (refer FIG. 3), a joint member may be another shape. For example, the pinion shaft 31 may be connected to the joint portion (joint member) formed at the lower end portion of the intermediate shaft 35 without using the universal joint 37 by serration coupling. Moreover, as shown in FIG. 7, although the cross-sectional shape of the 1st stopper part 7 and the groove end surface 13 was demonstrated as smooth arc shape, a cross section may be a linear shape other than this, for example.

1 is an overall schematic view showing an embodiment of a steering device of the present invention. It is a principal part perspective view of the steering apparatus of this invention. It is a principal part perspective view which shows the decomposition | disassembly state of the steering apparatus of this invention. It is a perspective view of a positioning member. It is sectional drawing which shows the state in which the positioning member was attached to the front-end | tip part of a pinion shaft. (A) is a partial cross section of the ring portion of the positioning member, and (b) is an enlarged view showing a portion to which the ring portion of the pinion shaft is attached. It is explanatory drawing which shows the state in which the ring part was attached to the pinion shaft. It is explanatory drawing of the conventional connection structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positioning member 2 Ring part 3 Projection piece 4 Engagement part 6 Serration protrusion 7 First stopper part 8 Second stopper part 9 Third stopper part 12 Serration groove 13 Groove end surface 14 Groove bottoms 21, 22 Joint yoke ( Joint member)
31 Pinion shaft (shaft)
32 Steering gear unit 33 Steering wheel 34 Steering shaft 35 Intermediate shaft 39 Circumferential protrusion

Claims (4)

A shaft, a joint member that is serrated and connected coaxially with the shaft, and a positioning member that is pre-attached to the shaft in order to position relative positions in the rotational direction and the axial direction of the joint member with respect to the shaft A connecting structure comprising:
On the outer peripheral surface of the shaft, a serration groove having a groove bottom located on the radially inner side of the outer peripheral surface of the shaft and a groove end surface located in an axially intermediate portion of the shaft is formed,
The positioning member has a ring portion in which a serration protrusion that fits into the serration groove is formed on an inner peripheral surface, and the joint member abuts from an axial direction,
The connection structure, wherein the serration protrusion of the ring portion serves as a stopper portion for restricting the position of the ring portion in the axial direction with respect to the shaft by contacting the groove end surface. A circumferential protrusion is formed on the outer peripheral surface of the shaft,
2. The connection structure according to claim 1, wherein the ring portion of the positioning member is formed with a second stopper portion that contacts the circumferential protrusion at the same time that the serration protrusion contacts the groove end surface. The positioning member has a protruding piece that protrudes in a radially outward direction and an axial direction of the ring portion,
The connection structure according to claim 1, wherein a third stopper portion that is in contact with the end surface of the shaft at the same time as the serration protrusion is in contact with the groove end surface is connected to the protruding piece. A steering gear unit having a pinion shaft for steering the wheels, a transmission shaft for transmitting rotation of the steering wheel to the pinion shaft, and a joint member for connecting the pinion shaft and the transmission shaft; With
The steering device according to claim 1, wherein the pinion shaft and the joint member are serration-coupled coaxially by the connection structure according to any one of claims 1 to 3.

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