JP2013234686A - Motion guide device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motion guide device which includes parts having high strength and is highly durable and highly reliable.SOLUTION: A motion guide device includes: a raceway member on which rolling element rolling sections are formed; a movement member on which loaded rolling element rolling sections facing the rolling element rolling sections are formed and which have rolling element return passages extending substantially parallel to the loaded rolling element rolling sections; a pair of lid members 6, 6 in which direction change paths 16 for connecting the loaded rolling element rolling sections and the rolling element return passages are formed; and a plurality of rolling elements arranged in a rollable manner within rolling element circulation routes configured from the loaded rolling element rolling sections, the rolling element return passages and the direction change paths 16. The movement member and the lid members are provided with a plurality of fixing means. Any one fixing means is disposed in the vicinity A of a scooping section 16a at which the direction change path 16 formed in the lid member 6 scoops the rolling element rolling from the loaded rolling element rolling section; and any other fixing means 21, 22 are disposed at positions close to a side opposite to the side on which the raceway rail is installed.

Description

  The present invention relates to a motion guide device such as a linear guide for guiding a moving body such as a table to move linearly or in a curved line.

  As a mechanical element for guiding the linear motion and curved motion of a moving body such as a table, a motion guide device in which rolling elements such as balls and rollers are interposed in the guide portion can provide light movement, so that the robot, It is used in various fields such as machinery, semiconductor / liquid crystal manufacturing equipment, and medical equipment.

  A linear guide, which is a kind of motion guide device, includes a track rail attached to a base and a moving block attached to the track rail so as to be capable of relative motion and to which a moving body is attached. The rolling rail rolling part extending along the longitudinal direction is formed on the track rail. On the other hand, the rolling block is provided with a rolling element circulation path that circulates the rolling elements while forming a load rolling element rolling part that faces the rolling element rolling part. Moreover, between the rolling-element rolling part of a track rail and the load rolling-element rolling part of a moving block, the rolling element is arranged so that rolling is possible. When the moving block moves linearly relative to the track rail, the rolling elements arranged between the track rail and the moving block roll, and circulate infinitely in the rolling element circulation path. And since such a linear guide is a machine element component which requires high reliability, the design and member selection supposing that it can be used stably for a long period of time are required.

  In addition, the following patent document 1 etc. exist as what discloses this kind of motion guidance apparatus.

JP 2011-153669 A

  By the way, in the conventional linear guide, a load rolling element rolling part that faces the rolling element rolling part of the track rail is formed, and a movement having a rolling element return passage that extends substantially parallel to the loaded rolling element rolling part. Block body (moving member) and a pair of end plates (lid members) provided at both front and rear ends in the moving direction of the moving block body to form a direction changing path connecting the load rolling element rolling section and the rolling element return passage. In combination, the moving block is configured. The moving block main body and the pair of end plates are only positioned on the outer side such as the upper side or the side where a fixing means such as a bolt can be installed due to the presence of the direction change path formed on the end plate. The connection was fixed by.

  However, since the conventional fixing structure described above is to connect and fix only a portion away from the position where the direction change path craws over the rolling element, for example, the impact load when the rolling element is scooped or the rolling element has poor circulation. The end plate is in a cantilevered state against the load (internal pressure) that pushes the end plate from the inner side to the outer side of the direction change path when it occurs. For this reason, if a bending stress exceeding the design value is generated on the end plate, there is a possibility that problems such as cracking of the end plate may occur. In particular, in the case of linear guides for applications where the relative movement of the moving block with respect to the track rail is performed at an ultra-high speed, or linear guides used in adverse environments where foreign matter enters the rolling element circulation path, end There is an increased possibility that the load applied to the plate will increase and that the rolling elements will not circulate properly. In view of this, there has been a demand for realizing a motion guide device having high component strength and durability, which can suitably realize a guide operation even in such a case.

  The present invention has been made in view of the problems existing in the above-described prior art, and an object thereof is to firmly connect and fix a moving block main body (moving member) and a pair of end plates (lid members). Thus, an object of the present invention is to provide a motion guide device having high component strength, durability and reliability.

  The motion guide device according to the present invention includes a raceway member in which a rolling element rolling part is formed, a load rolling element rolling part that faces the rolling element rolling part, and the load rolling element rolling part. A moving member having a rolling element return passage extending substantially in parallel with the moving member, and a direction changing path that is provided at both front and rear ends in the moving direction of the moving member and connects the load rolling element rolling portion and the rolling element return passage. A plurality of rolling elements arranged in a freely rolling manner in a rolling element circulation path composed of the load rolling element rolling portion, the rolling element return passage, and the direction changing path. The movement guide device includes a plurality of fixing means for fixing the moving member and the lid member to the moving member and the lid member, and any one fixing means is the lid The direction change path formed in the member is the load rolling element rolling Together provided in the vicinity of the rolling elements scoop scooping portion coming to rolling from one in which any other fixing means, characterized in that it is provided at a position closer to the counter-track rail installation side.

  According to the present invention, since the moving member and the pair of lid members can be firmly connected and fixed, it is possible to provide a motion guide device with high component strength and high durability and reliability.

It is a partial longitudinal cross-section perspective external view of the exercise | movement guide apparatus which concerns on this embodiment. It is a longitudinal cross-sectional view for demonstrating the internal structure of the exercise | movement guide apparatus which concerns on this embodiment. It is a figure which shows the cross section of the ball | bowl circulation path | route of the movement guide apparatus which concerns on this embodiment. It is a figure for demonstrating the design concept of the end plate which concerns on this embodiment. It is a conceptual diagram for demonstrating the difference of the fixed state of the moving block main body (moving member) in this embodiment and a prior art, and an end plate (lid member), and the fractional drawing (a) shows the case of this embodiment. The partial diagram (b) shows the case of the prior art. It is a figure which shows about the correlation of the position of the area | region A in which the fixing means of this embodiment is provided, and the position in which the conventional fixing means is provided. It is a figure which shows the structural example at the time of employ | adopting bolt fastening as the fixing means of this embodiment. It is a figure which shows the structural example at the time of employ | adopting welding fixation for the fixing means of this embodiment. It is a figure which shows the example of a structure different from FIG. 8 at the time of employ | adopting welding fixation for the fixing means of this embodiment. It is a figure which illustrates the end plate of the various forms which can apply this embodiment. It is a figure which illustrates the end plate of the various forms which can apply this embodiment. It is a figure which illustrates the end plate of the various forms which can apply this embodiment. It is a figure which illustrates the fixing means of various forms which can apply this embodiment. It is a figure which illustrates the fixing means of various forms which can apply this embodiment. It is a figure which illustrates the fixing means of various forms which can apply this embodiment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the drawings. The following embodiments do not limit the invention according to each claim, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. .

  First, the overall configuration of the motion guide apparatus according to the present embodiment will be described. Here, FIG. 1 is a partial vertical cross-sectional perspective external view of the motion guide device according to the present embodiment, and FIG. 2 is a vertical cross-sectional view for explaining the internal configuration of the motion guide device according to the present embodiment. FIG. 3 is a view showing a cross section of the ball circulation path of the motion guide apparatus according to the present embodiment. The motion guide device according to this embodiment is called a linear guide, and is a device that guides a moving body such as a table to reciprocate linearly with respect to a base.

  A track rail 1 as a track member is installed on a base (not shown). Mounting holes 2 are formed at equal intervals in the longitudinal direction from the upper surface to the lower surface of the track rail 1. By using coupling means such as bolts using the mounting holes 2, the lower surface of the track rail 1 is used as a base. Can be fixed against.

  Further, the track rail 1 is formed to be elongated in a straight line with a substantially square cross section. Ball rolling grooves 1 a extending along the longitudinal direction are formed on the left and right side surfaces of the track rail 1 as rolling element rolling portions. In this embodiment, the case where the ball rolling groove | channel 1a is formed in a total of four strips by two each on the right and left side surfaces is illustrated. As the cross-sectional shape of the ball rolling groove 1a, either a circular arc groove shape made of a single arc or a Gothic arch groove shape made of two arcs can be adopted. In addition, the number of strips of the ball rolling groove 1a, the contact angle between the ball rolling groove 1a and the ball 3, and the like can be variously set according to the load of the motion guide device. Further, in this type of motion guide device, since the ball 3 rolls, the ball rolling groove 1a is processed so as to reduce the surface roughness and is heat-treated so as to increase the hardness.

  As shown in FIG. 2, a moving block 4 as a moving member is assembled to the track rail 1 through a plurality of balls 3 so as to be capable of relative movement. The moving block 4 includes a metal moving block body 5 and a pair of resin end plates 6 as lid members provided at both ends of the moving block 4 in the moving direction. The moving block main body 5 is formed in a bowl shape as a whole, and hangs downward from the center portion 5a facing the upper surface of the track rail 1 and both ends in the width direction of the center portion 5a. And opposing side wall portions 5b. On the inner surfaces of the left and right side wall portions 5b of the moving block main body 5, there are two rolling ball rolling grooves 5c in total, four on the top and bottom as load rolling element rolling grooves facing the ball rolling grooves 1a of the track rail 1. Is formed. Since the plurality of balls 3 also roll in the load ball rolling groove 5c, the load ball rolling groove 5c is processed so as to reduce the surface roughness and heat-treated so as to increase the hardness. .

  Further, as shown in FIG. 1, the plurality of balls 3 are connected in series by a retainer band 8 as a ball holder for each ball circulation path. A plurality of cylindrical spacers 8 a are interposed between the plurality of balls 3. The side surfaces of the plurality of spacers 8a are coupled by a pair of strip-shaped coupling portions 8b. A pocket portion for holding the ball 3 is formed in the retainer band 8 by the strip-shaped connecting portion 8b and the plurality of spacers 8a. As shown in FIG. 2, the connecting portion 8 b is configured to protrude outward from the ball 3 when viewed from the traveling direction of the ball 3. On both sides of the load ball rolling groove 5c of the moving block main body 5, guide grooves 10 for guiding the connecting portion 8b protruding beyond the outer diameter of the ball 3 are processed. The guide groove 10 is formed by being processed into a resin molded body 11 that is integrally molded with the moving block body 5. The guide groove 10 has a ball holding function for preventing the ball 3 from dropping from the loaded ball rolling groove 5 c of the moving block 4 when the moving block 4 is removed from the track rail 1.

  As shown in FIG. 2, the left and right side wall portions 5b of the moving block body 5 are provided with ball return passages 5d extending in parallel with the load ball rolling grooves 5c as rolling element return passages. The same number of ball return passages 5d as the loaded ball rolling grooves 5c are provided. Further, since the diameter of the ball return passage 5d is larger than the diameter of the ball 3, the ball 3 is prevented from receiving a load in the ball return passage 5d. The ball 3 moves in the ball return path 5d while being pushed by the succeeding ball 3 or being pulled by the front ball 3 through the retainer band 8. The ball return passage 5d is formed by integrally molding the resin molding 13 in the through hole 12 opened in the moving block main body 5. Further, a guide groove 14 for guiding the connecting portion 8b of the retainer band 8 is also machined in the ball return passage 5d.

  End plates 6 as lid members are attached to both ends of the moving block body 5 in the moving direction. As shown in FIG. 3, the end plate 6 is formed with a U-shaped direction change path 16 that connects the loaded ball rolling groove 5c and the ball return path 5d. The end plate 6 is formed with the outer peripheral side of the direction change path 16. On the other hand, a return piece portion 17 constituting the inner peripheral side of the direction changing path 16 is integrally injection-molded on the end surface of the moving block body 5. Therefore, the direction change path 16 is formed by combining the end plate 6 and the return piece portion 17.

  A linearly extending load ball rolling groove 5c, a ball return passage 5d extending parallel to the load ball rolling groove 5c, and a U-shaped direction change path 16 connecting the load ball rolling groove 5c and the ball return passage 5d. Thus, a circuit-like ball circulation path is formed. A plurality of balls 3 held by the retainer band 8 are arranged and accommodated in this ball circulation path. When the moving block 4 is moved relative to the track rail 1, a plurality of balls 3 are loaded between the ball rolling groove 1 a of the track rail 1 and the load ball rolling groove 5 c of the moving block 4. It will be rolling on the ball rolling path. Further, the ball 3 rolled to one end of the load ball rolling groove 5c of the moving block 4 is scooped up by a scooping portion 16a provided on the end plate 6, and after passing through the U-shaped direction change path 16, Enter the ball return path 5d. Furthermore, the ball 3 that has passed through the ball return path 5d passes through the opposite direction changing path 16 and then enters the loaded ball rolling path again.

  Next, a description will be given of a fixed configuration between the moving block main body 5 and the end plate 6 in the present embodiment. Here, FIG. 4 is a figure for demonstrating the design concept of the end plate which concerns on this embodiment. FIG. 5 is a conceptual diagram for explaining the difference in the fixed state between the moving block main body (moving member) and the end plate (lid member) in the present embodiment and the prior art. In the case of the embodiment, the partial drawing (b) shows the case of the prior art. The end plate 6 shown in FIG. 4 is the same type as that used for the linear guide described above.

  In the conventional linear guide, bolt fastening is performed as a means for fixing the movable block main body 5 and the end plate 6, but as shown in FIG. 4, this type of end plate 6 has an outer periphery of the direction change path 16. Since the side is formed, the bolt holes are generally provided on the upper side of the end plate 6 having a relatively large space, such as a bolt hole denoted by reference numeral 21. . Further, even if a bolt hole is provided in the vicinity of the direction change path 16, a place away from the lifting portion 16 a included in the direction change path 16, such as a bolt hole indicated by reference numeral 22, that is, the anti-track rail installation side The bolt hole 22 could be provided only at a position close to.

  However, the installation positions of such conventional bolt holes 21 and 22 are such that the fixed ends of the bolt holes 21 and 22 are offset from one end of the end plate 6 as shown in the partial diagram (b) of FIG. For this reason, the end plate 6 is in a cantilever state. In this case, particularly, the side of the raised portion 16a to which the impact from the rolling element is applied is a free end, and therefore the end plate 6 is configured to receive the impact force from the rolling element on the free end side having low strength. It was. Moreover, the direction change path 16 formed in the end plate 6 has the thinnest center portion (indicated by the symbol α) of the bottom of the turn groove when the rolling element is turned. When a load from the rolling element is applied to 16a, the end plate 6 may be destroyed by applying stress to the central portion α of the lowest strength turn groove bottom.

  Therefore, in the present embodiment, the shaded area indicated by the symbol A in FIG. 4, that is, the direction change path 16 formed in the end plate 6 receives the ball 3 rolling from the loaded ball rolling groove 5 c. A fixing means for fixing the movable block main body 5 and the end plate 6 is provided in a region in the vicinity of the raised portion 16a. By providing the fixing means of the present embodiment in the vicinity of the lifting portion 16a of the direction changing path 16, the end plate 6 can be supported at both ends with respect to the movable block body 5 as shown in a partial diagram (a) in FIG. Since the connection is fixed in a beam state, the fixed state between the movable block main body 5 and the end plate 6 becomes very strong. By adopting such a configuration, it is possible to provide a motion guide device having high component strength, durability and reliability.

  In addition, about the area | region A in which the fixing means of this embodiment is provided, as shown in FIG. 4, when the fixed surface with the moving block main body 5 in the end plate 6 is seen from the front, the direction change path 16 in the fixed surface is concerned. It can be defined as a region closer to the track rail installation side than the center portion α of the bottom of the turn groove.

  Further, in the present embodiment, it has been found that a suitable positional relationship can be set for the mutual relationship between the position of the region A where the fixing means of the present embodiment is provided and the position where the conventional fixing means is provided. ing. That is, as shown in FIG. 6, the direction change path 16 formed in the end plate 6 is viewed from the fixed surface side with respect to the moving block main body 5 from the front, and the center portion α of the turn groove bottom when turning the rolling element, If the center line β passing through the route center of the direction change path 16 is grasped, the direction change path 16 can be divided into four regions corresponding to the first quadrant to the fourth quadrant by these virtual lines α and β. And it is suitable to set the area A in which the fixing means of this embodiment is provided in the second quadrant and / or the third quadrant and to set the conventional fixing means in the first quadrant and / or the fourth quadrant. is there. Thus, by arranging the fixing means of the present embodiment and the conventional fixing means, the end plate 6 can be fixedly connected at a position sandwiching the center portion α of the turn groove bottom. As for the positional relationship for such a fixed connection, assuming a virtual line connecting the fixing means of the present embodiment and the conventional fixing means, the virtual line is the center of the turn groove bottom in the direction change path 16. It can be defined as being configured to cross the part α.

  The setting conditions for the position of the region A where the fixing unit of the present embodiment is provided have been described above with reference to FIGS. Next, a specific configuration example of the fixing unit of the present embodiment will be described with reference to FIGS. FIG. 7 is a diagram showing a configuration example when bolt fastening is adopted as the fixing means of the present embodiment, and FIGS. 8 and 9 are configurations when welding fixing is adopted as the fixing means of the present embodiment. It is a figure which shows an example.

  As illustrated in FIG. 7, fastening means using bolts can be adopted as the fixing means of the present embodiment. As shown in FIG. 7, bolt holes 21 and 22 that are conventional fastening means are arranged in the first and fourth quadrants defined in FIG. On the other hand, the bolt hole 71 which is the fixing means of the present embodiment is disposed at the position of the third quadrant of the direction change path 16 located on the upper side and at the position of the second quadrant of the direction change path 16 located on the lower side. Yes. Assuming an imaginary line γ connecting the bolt holes 21 and 22 and the bolt hole 71, the imaginary line γ is configured to cross the central part α of the turn groove bottom in the direction change path 16. Therefore, according to the configuration example shown in FIG. 7, the end plate 6 can be firmly connected to the movable block main body 5 in the state of both-end support beams. Therefore, it is possible to provide a motion guide device having high component strength and high durability and reliability.

  Note that the region in which the bolt hole 71 that is the fixing means of the present embodiment can be installed must be narrower than the installation region of the bolt holes 21 and 22 that are the conventional fastening means. As for the size of, it must be smaller than the conventional bolt holes 21 and 22. Therefore, instead of the fastening means using bolts, it is possible to employ fixing means by welding and fixing as the fixing means of the present embodiment. 8 and 9 exemplify setting areas of the fixing means 81 and 91 by welding and fixing according to the present embodiment according to the positions where the bolt holes 21 and 22 as conventional fastening means are formed. The fixing means 81 and 91 by welding and fixing illustrated in FIGS. 8 and 9 are provided with ribs on the end plate 6 in advance, and this rib is used when fixing the end plate 6 and the moving block body 5. In this method, the end plate 6 and the movable block main body 5 are integrated with each other by melting them with a high frequency heat source or the like.

  Even when the fixing means based on welding and fixing as shown in FIGS. 8 and 9 is adopted, when the virtual line γ connecting the bolt holes 21 and 22 and the fixing means 81 and 91 is assumed, the virtual It is preferable that the line γ is configured to cross the central part α of the turn groove bottom in the direction change path 16. By adopting such a configuration, the end plate 6 can be firmly fixedly connected to the moving block main body 5 in the form of a doubly supported beam, and it is possible to provide a motion guide device with high component strength, durability and reliability. It becomes.

  As mentioned above, although preferred embodiment of this invention was described, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the embodiment.

  For example, in the above-described embodiment, the ball 3 is used as the rolling element, and the case where the present invention is applied to a case where the direction change path 16 formed in the end plate 6 is inclined is illustrated. It was. However, the present invention can be applied to various types of motion guide devices. For example, as illustrated in FIG. 10, the present invention can be applied to a case in which the direction change path 16 formed in the end plate 6 is set to face the horizontal direction or the vertical direction. Specifically, when the fixed surface of the end plate 6 with the movable block main body 5 is viewed from the front, the region A where the fixing means of the present invention is provided is the center of the turn groove bottom of the direction change path 16 on the fixed surface. It is preferable to set the region closer to the track rail installation side than α.

  Further, the relationship between the region A exemplified in FIG. 10 and the center part α of the turn groove bottom can be suitably applied to the end plate 6 in the case where a roller is used as the rolling element as shown in FIG. It is.

  Further, the present invention can be used for a relatively small shape in which, for example, as illustrated in FIG. 12, two direction change paths 16 that face in the horizontal direction are formed in the end plate 6. it can. Also in this case, when the fixed surface of the end plate 6 with the movable block main body 5 is viewed from the front, a place where the fixing means of the present invention is provided (welding means 121) is the turn of the direction change path 16 on the fixed surface. It is preferable to set the region closer to the track rail installation side than the center portion α of the groove bottom. In the case of FIG. 12, since the end plate 6 has a relatively compact shape, it is preferable that the fixing means is provided with a welding means 121 that can be installed even in a narrow area.

  Furthermore, as a fixing means that can be applied even in a narrow region as illustrated in FIG. 12, a band fixing device may be employed. FIG. 13 and FIG. 14 are shown as examples of band fixing as the fixing means of the present invention. Here, in FIG. 13, two bands 131 are arranged so as to sandwich the upper and lower sides of the load ball rolling groove 5c formed in the moving block body 5, and these two bands 131 are paired by bolts. It is fixed to the end plates 6 and 6. Further, FIG. 14 shows that a single band 141 is arranged so as to overlap above the load ball rolling groove 5c formed in the moving block main body 5, and this single band 141 is also paired with a bolt. It is fixed to the end plates 6 and 6.

  Furthermore, the fixing means of the present invention may be a mechanism that only presses the vicinity of the lifting portion 16a of the direction changing path 16 like a pressing portion 151 as the fixing means shown in FIG. Even in such a configuration, the same effect as the fixing means of the present embodiment described above can be exhibited. That is, as illustrated in FIG. 13 to FIG. 15, the fixing means of the present invention includes a fixing means by the bolt hole 71 and fixing means 81 and 91 by welding and fixing, as long as the same effects can be exhibited. Any form can be adopted. For example, as the fixing means according to the present invention, at least one of bolt fastening, rivet fixing, adhesive fixing, welding fixing, snap fitting, band fixing, or wire fixing, or a combination thereof can be employed.

  It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  1 track rail, 1a ball rolling groove, 2 mounting hole, 3 ball, 4 moving block, 5 moving block body, 5a central part, 5b side wall part, 5c load ball rolling groove, 5d ball return path, 6 end plate, 6b Side wall part, 8 Retainer band, 8a Spacer, 8b Connecting part, 10 Guide groove, 11 Resin molded body, 12 Through hole, 13 Resin molded body, 14 Guide groove, 16 Direction change path, 16a Raised part, 17 Return piece , 21, 22 (conventional) bolt hole, 71 bolt hole (which is a fixing means of the present embodiment), 81, 91 fixing means by welding fixation, 121 welding means, 131 double band, 141 single band, 151 Presser part, A region where the fixing means of this embodiment is provided, α center part of the turn groove bottom, β (through the path center of the direction change path 16 Center line, γ (imaginary line γ (connecting the conventional fixing means and the fixing means of this embodiment)).

Claims (4)

A raceway member on which rolling element rolling parts are formed;
A moving member having a rolling element return passage extending substantially parallel to the loaded rolling element rolling part, and a load rolling element rolling part facing the rolling element rolling part,
A pair of lid members which are provided at both front and rear ends in the moving direction of the moving member, and in which a direction changing path connecting the load rolling element rolling portion and the rolling element return path is formed;
A plurality of rolling elements arranged to roll freely in a rolling element circulation path constituted by the load rolling element rolling part, the rolling element return passage, and the direction change path;
In an exercise guidance device comprising:
The moving member and the lid member are provided with a plurality of fixing means for fixing the moving member and the lid member,
An arbitrary one fixing means is provided in the vicinity of the lifting part that crawls the rolling element rolling the direction change path formed in the lid member from the load rolling element rolling part,
Any other fixing means is provided at a position close to the anti-track rail installation side. The motion guide device according to claim 1,
When the fixing surface of the lid member with the moving member is viewed from the front, the fixing means is located on a region closer to the track member installation side than the center portion of the turn groove bottom of the direction change path on the fixing surface. A motion guide device provided. The motion guide apparatus according to claim 1 or 2,
When the virtual surface connecting the arbitrary one fixing means and the arbitrary other fixing means is assumed when the fixing surface of the lid member with the moving member is viewed from the front, the virtual line changes the direction. A motion guide device configured to cross a road. In the exercise | movement guide apparatus of any one of Claims 1-3,
The motion guide device is characterized in that the fixing means is at least one of bolt fastening, rivet fixing, adhesive fixing, welding fixing, snap fitting, band fixing, or wire fixing, or a combination thereof.

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