JP2008175324A - Ball connection body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball connection body downsizing an endless circulating path for balls to contribute to downsizing a linear guide or a ball screw device having the endless circulating path for the balls by setting a ball turning radius at the curved portion of the endless circulating path to be smaller. <P>SOLUTION: The ball connection body 11 is incorporated in the endless circulating path for the balls consisting of a load path and a non-load path in use for rollingly holding a number of balls in one line. It comprises: a pair of belt parts 12 arranged on both sides across the balls 1 in one line; a number of ball holding members 13 formed integrally with the belt parts 12 and having spherical seats 15 which embrace the ball spherical faces; and bridge parts 14 for connecting the pair of belt parts 12 to each other and keeping a space between the ball holding members 13 opposed to each other across the balls 1 constant. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a ball connection in which a large number of balls are arranged in a row and these balls are connected to each other and incorporated in an infinite circulation path of the balls provided in a linear guide device, a ball screw device or the like. In particular, the present invention relates to a ball coupling body that can circulate while securely holding a ball even when the curvature of a curved portion in an infinite circulation path is small.

  Conventionally, as a linear guide device that guides a movable body such as a table along a fixed portion such as a bed, a track rail having a ball rolling groove and a load rolling roller that constitutes a load passage facing the ball rolling groove. A moving block that has a running groove and a no-load passage that circulates the ball from one end of the load passage to the other end, moves along the track rail, and loads between the moving block and the track rail. It is known that it is composed of a large number of balls that circulate while being loaded and circulate through an infinite circuit constituted by a load passage and a no-load passage of the moving block.

  In the conventional linear guide device configured as described above, since the infinite circulation path of the moving block is filled with balls, when the moving block moves along the track rail, adjacent balls collide with each other or There is a problem in that the balls circulate in the infinite circulation path while rubbing each other, so that the balls are worn early and the life of the apparatus is shortened.

  In order to solve such problems, there has been proposed a linear guide device in which a ball coupling body in which a large number of balls are aligned and held is incorporated in the infinite circulation path (Japanese Patent Laid-Open No. 5-52217). As shown in FIGS. 8 and 9, the ball connector 100 includes spacers 102 interposed between adjacent balls 101, and each spacer 102 is formed by a pair of belt members 103 along the ball arrangement direction. The balls 101 are connected in a rosary shape, and are manufactured by injection molding of a flexible resin in which the balls 101 are arranged as cores in a mold. Each spacer 102 is provided with a concave spherical seat that holds the spherical surface of the ball 101, and the ball is rotatably held by spacers positioned in front of and behind the ball.

As shown in FIG. 10, the conventional ball coupling body 100 configured as described above is incorporated in the endless circulation path 105 of the moving block 104, and the endless circulation path together with the ball 101 as the movement block 104 moves with respect to the track rail 106. Circulate in 105. Since the ball coupling body 100 is formed from a flexible resin and can be freely bent with a certain degree of freedom, when moving in the endless circulation path 105, the linear portion of the endless circulation path 105 and It is possible to freely deform following the curved portion. Since the spacers 102 are interposed between the adjacent balls 101, mutual friction and collision between the balls 101 can be prevented, and wear of the balls 101 can be prevented as much as possible. It was.
JP-A-5-52217

  In such a conventional ball connector 100, spacers are disposed between adjacent balls, and the belt members interconnect the spacers. Since the belt member is formed integrally with the spacer, and the spacer has a thickness, the belt member is difficult to bend at the coupling portion with the spacer, and is bent at the intermediate portion connecting the spacers. It had the characteristic of being easy.

  For this reason, when the ball coupling body is bent at the curved portion of the infinite circulation path, the belt member does not bend uniformly, but bends in several stages like a polygon, with the portion overlapping the center of the ball as the apex. Was so curved. When the belt member is bent in such a manner that it bends in stages, the spacer is positioned on the inner side of the original ball trajectory in the curved portion of the infinite circuit, and outside the curved portion of the infinite circuit. Since the space between the adjacent spacers is greatly increased, there is a concern that the ball may slip out from between the spacers in such a curved portion.

  Setting the size of the spacer larger than the ball diameter ensures that the ball is held by the spacer, and the ball can be reliably held on the ball coupling body even at the curved portion of the infinite circulation path. However, if the size of the spacer becomes too large with respect to the ball diameter, the inner wall of the infinite circulation path and the spacer interfere with each other at the curved portion of the infinite circulation path, so that the size of the spacer is naturally limited.

  That is, in the conventional ball coupled body, a spacer is provided between adjacent balls, and the ball is rotatably held by the spacer. Therefore, when designing the curved portion of the infinite circuit, the ball in the curved portion is designed. The minimum value of the turning radius is limited due to the spacer of the ball coupling body, which is an obstacle to the compact construction of the infinite circulation path of the ball.

  The present invention has been made in view of such problems, and the object of the present invention is to make it possible to set a small turning radius of the ball in the curved portion of the infinite circulation path, thereby making the infinite circulation of the ball. An object of the present invention is to provide a ball coupling body that can contribute to the miniaturization of a linear guide device and a ball screw device that have a path that is downsized and thus has an infinite circulation path for balls.

  That is, the present invention is a ball coupling body which is used by being incorporated in an infinite circulation path of balls composed of a load passage and a no-load passage, and which holds a plurality of balls in a row so as to freely roll. A pair of belt portions disposed on both sides thereof, a plurality of ball holding members formed integrally with each belt portion and having a spherical seat that encloses the ball spherical surface, and the pair of belt portions connected to each other And a bridging portion that maintains a constant interval between the ball holding members facing each other across the ball.

  According to the ball coupling body of the present invention configured as described above, the ball holding member having the spherical seat for holding the ball does not exist between the adjacent balls, and is provided integrally with each belt member. And located on both sides of the ball connecting body in the width direction. That is, each ball holding member provided on each belt member is opposed to another ball holding member located on the opposite side across the ball, thereby holding the ball so as to be sandwiched between the pair of ball holding members. ing. Therefore, even if the ball coupling body configured in this way is incorporated in the infinite circulation path of the ball and the ball coupling body is curved in the curved portion of the infinite circulation path, the positional relationship between the ball holding member and the ball is infinite. There is no change between the straight portion and the curved portion, and the ball can always be held stably.

  In addition, since the position of the ball holding member in the infinite circuit is always determined with reference to the ball, the ball holding member does not interfere with the inner wall of the infinite circuit if the diameter is smaller than the ball diameter. It becomes possible to set a small turning radius of the ball in the curved portion of the infinite circulation path. As a result, the infinite circulation path of the ball can be configured in a compact manner, and it is possible to reduce the size of the linear guide device and the ball screw device having such an infinite circulation path.

  Further, since the ball holding member does not exist in the rolling direction of each ball and is positioned on both sides of the ball with respect to the rolling direction, the friction between the ball and the ball holding member can be reduced. It becomes possible to roll the ball lighter than before.

  Here, if the distance between the pair of ball holding members facing each other with the ball interposed therebetween increases, the ball falls out from between the ball holding members. The bridging portion functions to connect a pair of belt members arranged with the ball between them and maintain a constant distance between the pair of ball holding members facing each other. Therefore, as long as such a function is ensured, it is not necessary to provide the bridging portion for each ball. For example, the bridging portion may be provided at a ratio of one place for a plurality of balls.

  In addition, the infinite circulation path of the ball in the linear guide device and the ball screw device is composed of a load passage where the ball rolls while applying a load and a no-load passage where the ball released from the load state rolls, When a ball coupling body is incorporated and used in such an infinite circulation path, the ball coupling body is locally compressed or stretched while circulating. Therefore, from the viewpoint of preventing the adjacent balls from interfering with each other when locally compressed or preventing the ball and other members from interfering with each other, the adjacent balls and the balls are not in contact with each other. It is preferable to provide a space between these balls. This makes it possible to prevent a large resistance from acting on the rotation of the ball even when the ball coupled body is locally compressed in the endless circulation path. Further, since the space provided between the balls also functions as a lubricant holding space, the balls can be more effectively lubricated.

  Further, the bridging portion is located between the balls and couples the pair of belt members to each other, but the ball is preferably not in contact with the bridging portion.

  Hereinafter, the ball coupling body of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing an example of a linear guide device using the ball coupling body of the present invention. The linear guide device is fixed to a movable body such as a table rail 2 on which a rolling surface of the ball 1 is formed along the longitudinal direction, and is assembled to the track rail 2 via a large number of balls 1. The moving block 3 is connected to a plurality of balls 1 connected in a strip shape and circulated in an infinite circulation path provided in the moving block 3.

  First, the track rail 2 extends linearly in a direction perpendicular to the paper surface of FIG. 1, and its length is arbitrarily set according to the application of the linear guide device. A cross section perpendicular to the longitudinal direction of the track rail 2 is formed in a substantially rectangular shape. The track rail 2 is formed with rolling surfaces 20 of the balls 1 along the longitudinal direction. The balls 1 roll on the rolling surfaces 20 while applying a load acting on the moving block 3. To do. In the linear guide apparatus shown in FIG. 1, the rolling surface 20 is formed in a total of four strips by two so as to sandwich the upper corner portion of the track rail 2. The number and arrangement of the rolling surfaces 20 are as follows. The design can be appropriately changed according to the use of the linear guide device and the magnitude of the load. In addition, bolt mounting holes 21 are formed in the track rail 2 at appropriate intervals in the longitudinal direction, and the track rail 2 is fixed to various mechanical devices by fixing bolts inserted into the bolt mounting holes 21.

  On the other hand, the moving block 3 has a substantially saddle section in cross section and is assembled to the track rail 2 so as to straddle it. The upper surface of the moving block 3 is a mounting surface 30 for a movable body such as a table, and a tap hole 31 for connecting the movable body with a fixing bolt is formed. A load rolling surface 32 constituting a load path of the ball 1 is formed on the inner surface facing the track rail 2 so as to face the rolling surface 20 of the track rail 2. It exists in the passage and rolls while applying a load between the load rolling surface 32 of the moving block 3 and the rolling surface 20 of the track rail 2.

  Ball holding portions 34 are formed on both sides of each load rolling surface 32 so as to cover the load rolling surface 32, and when the moving block 3 is removed from the track rail 2, This prevents the ball 1 located in the position from rolling off the moving block 3.

  Further, in the moving block 3, a no-load passage is formed corresponding to each load passage, and an infinite circulation path of the ball is formed from the load passage and the no-load passage. That is, the ball 1 rolls in the load passage while applying a load, then rolls in the no-load passage in a state of being released from the load, and is returned to the load passage again. Thereby, the moving block 3 can move along the track rail 2 without limitation. The no-load passage includes a ball return hole 33 formed in parallel with the load passage (load rolling surface 32), and a pair of direction change passages that connect and connect the end of the load passage and the end of the ball return hole 33. It consists of and.

  FIG. 2 is an exploded perspective view showing the moving block 3. The moving block 3 includes a block main body 4 in which the load rolling surface 32 and the ball return hole 33 are formed, and a pair of end caps 5 fixed to both front and rear end surfaces of the block main body 4. In FIG. 1, one end cap 5 is omitted. Each end cap 5 is made of a synthetic resin, and a direction changing path 50 constituting a part of the infinite circulation path of the ball 1 is formed on the inner side surface in contact with the block body 4. The direction change path 50 is formed in a substantially U shape so as to change the traveling direction of the ball 1 by 180 °. By fixing the end cap 5 to the block body 4, a load rolling surface of the block body 4 is obtained. The ball 1 that has finished rolling 32 can be guided to the ball return hole 33, or the ball 1 that has rolled from the ball return hole 33 can be guided to the load rolling surface 32.

  Furthermore, semicircular ball guide portions 35 are projected on both front and rear end faces of the block body 4, and enter and exit the ball return hole 33 of the block body 4 in combination with the direction changing path 50 of the end cap 5. The ball 1 to be guided is guided.

  The block body 4 is formed by injecting synthetic resin onto a metal block core by injection molding, and has mechanical strength such as the mounting surface 30 of the movable body and the load rolling surface 32 of the ball 1 described above. The required part is formed in the block core. On the other hand, portions where the mechanical strength is not important, such as the ball return hole 33, the ball holding portion 34, and the ball guide portion 35, are formed of synthetic resin, and the block body 4 is reduced in weight as much as possible.

  3, 4, and 5 show the ball coupling body 10 incorporated in the endless circulation path of the ball 1 provided in the moving block 3. The ball connection body 10 is composed of a connection body belt 11 molded from a synthetic resin and having flexibility, and a large number of balls 1 arranged in a row on the connection body belt 11. Is rotatably held by the connecting belt 11. That is, as long as no external force is exerted, each ball 1 does not fall out of the connecting belt 11, and a large number of balls 1 arranged on the connecting belt 11 can be handled as a group.

  The connecting belt 11 includes a pair of belt portions 12 disposed on both sides of the balls arranged in a row, and a plurality of ball holding members 13 provided on the belt portion 12 corresponding to the balls 1. And a plurality of bridging portions 14 for mutually connecting a pair of belt portions 12 arranged with the ball 1 interposed therebetween. The belt portion 12, the ball holding member 13, and the bridging portion 14 are integrally formed of synthetic resin. Each ball holding member 13 includes a spherical seat 15 that holds a part of the spherical surface of the ball 1, and the ball holding member 13 provided on one belt portion 12 has the other belt portion 12 sandwiching the ball 1. The ball 1 is opposed to the ball holding member 13, and the ball 1 is sandwiched between the spherical seats 15 facing each other, so that the ball 1 is rotatably held by the connecting belt 11.

  The balls 1 are arranged on the connecting belt 11 at an interval so as not to contact the adjacent balls 1, and the bridging portion 14 is located between the adjacent balls 1 and the balls 1. . In addition, a gap is also formed between the ball 1 and the bridging portion 14, and each ball 1 and the bridging portion 14 are kept in non-contact. That is, between the balls 1 adjacent to each other, the ball 1 is kept at a distance equal to or greater than the thickness of the bridging portion 14, and a buffer space 16 is formed to absorb the distance variation between the balls.

  The ball connector 10 thus configured is used by being incorporated in an infinite circulation path of the ball 1 in the moving block 3. When the moving block 3 moves along the track rail 2, the balls 1 arranged in the ball coupling body 10 apply a load between the rolling surface 20 of the track rail 2 and the load rolling surface 32 of the moving block 3. The ball coupled body 10 circulates in the infinite circulation path of the moving block 3 as the balls 1 roll.

  When incorporating the ball coupling body 10 into the endless circulation path of the moving block 3, the ball coupling body 10 may be formed endlessly within the endless circulation path by joining ends together, and the ends may be coupled. Instead, the inside of the endless circuit may be circulated with an arbitrary gap formed between the end portions. However, as described above, the infinite circulation path is composed of a load path and a no-load path, and the ball coupling body 10 receives a compressive force or a pulling force along the circulation direction when moving between the load path and the no-load path. In order to avoid the trouble that the connecting belt 11 breaks unintentionally, the end portions of the ball connecting body 10 are not joined in the endless circulation path, and an arbitrary amount of them is interposed between these end portions. It is preferable to form a gap.

  Further, while the ball coupling body 10 circulates in the infinite circulation path, the compression force or the pulling force acts on the ball coupling body 10 as described above, and the balls 1 are evenly arranged on the coupling belt 11. Even if it does, the space | interval of the ball | bowl 1 which mutually adjoins will fluctuate | deviate by expansion-contraction of the coupling body belt 11 made from a synthetic resin. For this reason, if the buffer space 16 is formed between the balls 1 and 1, even if the distance between the balls 1 slightly fluctuates due to the influence of the compressive force or the pulling force, the balls 1 are mutually connected. There is no buffering, and the ball 1 can always rotate smoothly. Further, in a state before the ball coupling body 10 is incorporated into the infinite circulation path, a space is also formed between the bridging portion 14 and the ball 1 and both are maintained in a non-contact state. Even when the ball fluctuates slightly due to the influence of the compressive force or the pulling force, it is possible to avoid the ball 1 being strongly pressed against the bridging portion 14, and also in this respect, the ball 1 rolls in the infinite circuit. Can be done smoothly.

  FIG. 6 illustrates the curved state of the ball coupling body 10 inside the direction change path 50 provided in the moving block 3. On the other hand, FIG. 7 depicts the state of bending inside the direction change path 50 of the conventional ball connector 100 shown in FIGS. 8 and 9.

  In the conventional ball coupling body 100 shown in FIG. 7, a spacer 102 is disposed between the balls 101, and the ball 101 is encapsulated in a spherical surface by a pair of spacers 102 positioned in the front and rear in the circulation direction. . In addition, since the belt member 103 that couples the spacers 102 is formed integrally with the spacer 102, the belt member 103 is hard at a portion where the spacers 102 are coupled, and the spacer 102 is between the spacers 102 and 102. That is, it was soft at the portion overlapping the spherical surface of the ball 101. For this reason, when the conventional ball coupling body 100 is curved in the direction change path, the ball coupling body 100 is not curved with a uniform curvature, but is bent stepwise between the spacers 102 to form a polygonal shape. Draw a shape similar to. At this time, paying attention to the pair of spacers 102 positioned in front of and behind the ball 101, the spacers 102 expand at an angle θ, and when this angle increases, the ball 101 moves to the outside of the curved ball coupling body 100. It will fall off.

  Further, when the conventional ball coupling body 100 is curved in the direction change path 50, the spacer 102 is positioned inside the arc-shaped locus followed by the ball 101 in the direction change path 50. Is likely to interfere with the inner peripheral wall of the direction change path 50, that is, the ball guide portion 35.

  For this reason, in the conventional ball connector 100, the curvature of the direction change path 50 cannot be set large, and the interval between the load rolling surface 32 and the ball return hole 33 provided in parallel can be set large. I had to.

  On the other hand, when the ball coupling body 10 of the present invention shown in FIGS. 3 to 5 is curved inside the direction change path 50, as shown in FIG. The ball holding member 13 travels in the direction change path 50 while drawing a trajectory that substantially matches the trajectory of the ball 1 in the direction change path 50. become. For this reason, even if the ball coupling body 10 is greatly curved, the holding state of the ball 1 by the ball holding member 13 does not change, and the ball 1 can be held on the coupling belt 11 in a stable state at all times. It has become.

  Further, in this way, in the ball coupling body 10 of the present invention, the ball holding member 13 travels in the direction changing path 50 while drawing a locus that substantially coincides with the ball 1, and there is a spacer between the ball 1 and the ball 1. Therefore, even when the ball coupling body 10 is greatly curved, a part of the coupling belt 11 does not interfere with the inner peripheral wall of the direction change path 50, that is, the ball guide portion 35.

  Therefore, if the ball coupling body 10 of the present invention is used, the ball coupling body 10 can be greatly curved in the endless circulation path of the ball 1. For example, in the linear guide apparatus described above, The distance between the load rolling surface 32 and the ball return hole 33 can be reduced, and the moving block 3 can be reduced in size.

  In the above description, the example in which the ball coupling body 10 of the present invention is incorporated in the infinite circulation path of the ball 1 in the linear guide device has been described. However, other than this, for example, the ball spline and the ball screw device in the ball screw device are described. It is also possible to incorporate the ball coupling body of the present invention into an infinite circuit. Even in such a case, it is possible to greatly reduce the size of the spline nut or the screw nut because the ball coupling body 10 can be greatly curved in the endless circulation path.

It is sectional drawing which shows an example of the linear guide apparatus using the ball | bowl coupling body of this invention. It is a disassembled perspective view of the moving block of the linear guide apparatus shown in FIG. It is a front view which shows an example of the ball | bowl coupling body to which this invention is applied. It is a top view of the ball | bowl coupling body shown in FIG. It is the VV sectional view taken on the line of FIG. It is sectional drawing which shows the curved state of the ball | bowl coupling body of this invention in the direction change path of a linear guide apparatus. It is sectional drawing which shows the curved state of the conventional ball coupling body in the direction change path of a linear guide apparatus. It is a top view which shows the conventional ball | bowl coupling body. It is a side view of the ball | bowl coupling body shown in FIG. It is sectional drawing which shows the state which integrated the conventional ball coupling body shown in the figure in the ball | bowl infinite circuit of a linear guide device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Ball, 2 ... Track rail, 3 ... Moving block, 10 ... Ball connection body, 11 ... Connection body belt, 12 ... Belt part, 13 ... Ball holding member, 14 ... Bridge part

Claims (3)

A ball coupling body that is used by being incorporated in an infinite circulation path of a ball comprising a load path and a no-load path, holding a large number of balls in a row so as to freely roll.
A pair of belt portions disposed on both sides of a row of balls, a plurality of ball holding members having a spherical seat formed integrally with each belt portion and holding the ball spherical surface, and the pair of belts And a bridging portion that connects the portions to each other and maintains a constant distance between the opposing ball holding members across the ball. 2. The ball coupling body according to claim 1, wherein the balls adjacent to each other are not in contact with each other, and a space is provided between these balls. 3. The ball coupling body according to claim 2, wherein the bridging portion is located between adjacent balls, and the spherical surface of the ball and the bridging portion are not in contact with each other.

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