JP2008286321A - Linear motion guide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear motion guide which enables a guide rail to be easily and strongly fixed to a base by a fixation member, and which can securely prevent displacement of a cage from a slider. <P>SOLUTION: The linear motion guide of limited stroke type is provided with the guide rail 2, the slider 4, a plurality of rolling bodies 6, and a cage 8. An attachment hole 2h is formed in the guide rail and connected to a fixation hole which is formed on the base, and the fixation member is inserted in it. Then a rack gear 2g extended along the guide rail is provided in the part 2a opposite to the slider. A rack gear 4g which is extended in the movement direction of the slider is provided in the part 4a opposite to the guide rail by making the rack gear on the guide rail side and each of the profiles 2j, 4j, reverse to each other. On the other hand, a pinion gear 8g is attached to the cage with possible spinning and placed between the rack gears is mutually engaged with the rack gears. The rack gear on the guide rail side is positioned by avoiding the attachment hole of the guide rail. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a linear motion guide device that moves various products, for example, in manufacturing, inspection, and the like, and more particularly, to an improvement of a linear motion guide device having a finite rolling element trajectory (stroke).

  2. Description of the Related Art Conventionally, for example, machine tools (table devices and the like) that move various parts and products for manufacturing and inspection are known. For example, such a table device includes a base, a linear motion guide device disposed on the base, a moving table guided by the linear motion guide device to reciprocate, and a reciprocating movement of the movable table. A positioning mechanism for stopping at a predetermined position is provided.

  In this case, the linear motion guide device includes a guide rail that extends linearly in a predetermined direction (for example, the longitudinal direction of the base), a slider that can reciprocate along the guide rail, and the guide rail. A plurality of rolling elements that are interposed between the sliders and roll along the guide rail are provided. According to the table device configured in this way, the moving table can be reciprocated by a positioning mechanism (for example, a ball screw mechanism, a belt mechanism, a linear motor mechanism, etc.) while being guided by the linear motion guide device. At the same time, it can be stopped at a predetermined position. That is, in such a table device, the moving table is configured to be able to reciprocate along the guide rail via the slider and to stop at a predetermined position.

  Further, in the linear motion guide device using the rolling elements in this way, a structure that can receive loads from various directions by arranging a plurality of (generally, even number) rolling element rows symmetrically. Yes. Furthermore, the preload is applied to the rolling elements to eliminate backlash and to obtain high support rigidity.

  By the way, such linear motion guide devices are roughly classified into a type in which the rolling element trajectory (stroke) is infinite (hereinafter referred to as infinite stroke type) and a type in which the stroke is limited (hereinafter referred to as finite stroke type). Can do. A configuration example of an infinite stroke type is disclosed in Patent Document 1, and a configuration example of a finite stroke type is disclosed in Patent Document 2.

  In the infinite stroke type, when the slider is moved along the guide rail, the rolling element moves along a rolling path formed between the slider and the guide rail at a predetermined speed (relative to the slider and the guide rail). Rolls in the moving direction of the slider at about half the speed). Therefore, each rolling element that has rolled on the rolling path eventually rolls out from the end of the rolling path, and then passes through the switching path of the end cap into the rolling element passage that penetrates the slider in the moving direction. . Then, after traveling in the moving direction of the slider through the rolling element passage, the rolling element passage is again transferred to the rolling path via the end cap conversion path, and rolls there. Note that the end caps are members fixed to both ends in the moving direction of the slider, and formed therein with a conversion path that allows the rolling path and the rolling element path to communicate with each other.

  In this way, the infinite stroke type allows the slider to reciprocate by approximately the same distance as the extension length of the guide rail because the rolling element is circulated by the conversion path and the rolling element passage, and the moving distance of the moving table is compared. It has a feature that it can be set as long as possible.

  By the way, in the infinite stroke type, the rolling element moves in and out of the load zone (the portion of the rolling path formed between the guide rail and the slider where the rolling element receives a load). Therefore, the position and size of the force that the rolling element pushes the slider changes as the rolling element moves. If the rolling elements of a plurality of rolling element rows have the same timing for entering and exiting between the load zone and the non-load zone (where the rolling element is not loaded, the part of the conversion path and the rolling element passage), this The “force that the rolling element pushes the slider” cancels each other between the rolling element rows.

  However, in the infinite stroke type, the rolling elements of each rolling element row are not in a restrained state in which the timing of entering and exiting between the load zone and the non-load zone matches, and the positions of the rolling elements in each rolling row are different. It is. Therefore, the “force that the rolling element pushes the slider” slightly changes for each rolling element row, and the balance of these forces is slightly lost, resulting in a slight motion accuracy error in the slider. This motion accuracy error is called “rolling body passing vibration” or the like.

As described above, the deviation of the rolling element entry / exit timing between the rolling element rows between the load zone (rolling path) and the non-load zone (turning path) of the rolling element track affects the motion accuracy of the slider. give. For example, a decrease in the slider handling accuracy may cause a decrease in the positioning accuracy and running accuracy of the moving table.
Therefore, in a machine tool (for example, a table device) that requires the slider to be moved with extremely high accuracy, an infinite stroke type may not be adopted as the linear motion guide device depending on the degree of the required accuracy.

  On the other hand, in the finite stroke type, as shown in FIGS. 3A to 3C, a cage (cage) that rotatably holds rolling elements (cylindrical rollers) 50 one by one in the pocket 48p. 48 is interposed between the guide rail 40 and the slider 42, and rolls on a rolling path formed between the guide rail 40 and the slider 42 with the rolling element 50 held by the cage 48. In this case, each rolling element 50 is not circulated as in the infinite stroke type described above, and in a load zone where the rolling element 50 receives a load between the guide rail 40 and the slider 42, the guide rail The rolling path is moved while rotating in the pocket 48 p of the cage 48 in a state where the load is always received from the cage 40, and the slider 42 is moved along the guide rail 40 via the cage 48. The cage 48 has a structure in which a plurality of pockets 48p for holding the rolling element 50 rotatably is formed side by side along the longitudinal direction, and the cage 48 extends in the same direction as the moving direction of the slider 42. Although it is moved together with the slider 42, the moving distance at that time is substantially half of the moving distance of the slider 42.

In such a finite stroke type, the positions of the rolling elements 50 in each row can always be aligned by the cage 48, so that the timing at which the rolling elements 50 enter and exit the load zone can be aligned in each row. Therefore, even if the force with which the rolling element 50 pushes the slider 42 fluctuates in each row, the timing of the fluctuation can be made uniform. It can be kept small.
Moreover, since each rolling element 50 is rotatably held one by one in the pocket 48p of the cage 48, it does not contact each other and can always roll on the rolling path stably.

  Therefore, the finite stroke type can suppress the rolling element passing vibration and increase the motion accuracy of the slider 42, and thus can position the moving table (not shown) with high accuracy.

  However, in such a finite stroke type, when the slider repeats reciprocating movement along the guide rail, the rolling element rolls on the rolling path of the guide rail when the moving speed fluctuates or the moving direction changes. At this time, a slight slip may occur between the rolling element, the guide rail, and the slider. When the slider further repeats reciprocating motion, the relative position of the cage with respect to the guide rail and the slider may be gradually shifted from the original position due to the superposition of such minute slips.

Therefore, various measures have been conventionally taken in order to prevent such a shift of the cage in the finite stroke type.
For example, Patent Document 2 discloses, as an example, a configuration of a linear motion guide device (finite stroke type) provided with a pair of rack members (rack gears) arranged opposite to each other and pinion gears that can mesh with these rack members. Yes.

  In this linear motion guide device, as shown in FIGS. 4A to 4C, a bed (corresponding to the above-mentioned guide rail) 60 and a table (corresponding to the above-mentioned slider) 62 are arranged facing each other. A rolling element (ball) 70 held in a pocket of the cage 68 is interposed between the bed 60 and the table 62 together with the cage 68. The bed 60, the table 62, and the cage 68 are all substantially U-shaped in cross section, and the cage 68 is positioned on the bed 60 so as to cover the bed 60. The table 62 is positioned on the retainer 68 so as to cover the retainer 68. Further, raceway grooves 60a and 62a for rolling the rolling elements (balls) 70 are formed to face each other on the outer side surface of the bed 60 and the inner side surface of the table 62, and a cage is provided between the raceway grooves 60a and 62a. The table 62 is moved along the bed 60 when the rolling element (ball) 70 rolls while being held by 68.

  The bed 60 and the table 62 are provided with one rack member 64a and 64b, respectively, facing each other, and the retainer 68 can be engaged with these rack members 64a and 64b. A pinion gear 66 is rotatably attached. In this case, the rack members 64a and 64b are fixed at a substantially intermediate position in the width direction of the bed 60 and the table 62 (the left-right direction in FIG. 4A), whereas the pinion gear 66 is connected to the cage 68. It is positioned in a long hole formed through the central portion in the width direction (the same direction in the figure) and the longitudinal direction (movement direction).

Accordingly, when the table 62 is moved along the bed 60, the linear motion is transmitted to the holder 68 through the rolling elements (balls) 70, and the holder 68 moves along the bed 60 in the same direction. Is done. At that time, the pinion gear 66 attached to the retainer 68 moves along the bed 60 together with the retainer 68 while being engaged with the rack members 64a and 64b.
Therefore, even when the table 62 repeats reciprocating motion and a slight slip occurs between the rolling element (ball) 70 and the bed 60 and the table 62 when the moving speed fluctuates or when the moving direction is changed, The retainer 68 moves along the bed 60 because the pinion gear 66 meshes with the rack members 64a and 64b and rotates. For this reason, the retainer 68 can always be moved together with the rolling elements (balls) 70, and the relative position of the retainer 68 with respect to the table 62 can be prevented from shifting.
JP 2005-180656 A Japanese Patent No. 2667516

  In the linear motion guide device having such a structure, the bed 60 is fastened and fixed to a base (not shown) with bolts. 4 (b) and 4 (c), the bed 60 is inserted with a bolt at an intermediate position in the width direction (vertical direction in FIG. Through holes (bed mounting holes) 60h for fastening are formed at predetermined intervals along the longitudinal direction, and the table 62 is also at an intermediate position in the width direction (vertical direction in FIG. Bolt insertion through-holes (table through-holes) 62h that can communicate with the bed through-holes 60h are formed (one as an example before and after in the movement direction). The long hole (not shown) of the cage 68 described above is formed so as to be able to communicate with both the bed mounting hole 60h and the table through hole 62h.

  As a result, the retainer 68 holding the table 62 and the rolling elements (balls) 70 is assembled, and the bed 60 (hereinafter referred to as the bed assembly 60) integrated therewith is set to the base stand in this state. It can be fastened and fixed with a bolt (not shown). That is, even if the table 62, the rolling elements (balls) 70 and the retainer 68 and the bed 60 are integrated, the bed mounting hole 60h, the table through hole 62h, and the long holes (not shown) of the retainer 68 are provided. The bed assembly 60 can be fastened and fixed to the base (not shown) by connecting the bolts through the holes and fastening the bolts to the fixing holes of the base (not shown).

  However, as shown in FIGS. 4B and 4C, the bed mounting hole 60h, the table through hole 62h, and the long holes (not shown) of the retainer 68 are formed in the width direction of the bed 60, the table 62, and the retainer 68, respectively. The rack members 64a and 64b are disposed so as to block the bed mounting hole 60h and the table through hole 62h. For this reason, the rack members 64a and 64b need to be disposed with respect to the fixed bed assembly 60 after the bed assembly 60 is fixed to the base (not shown).

  At that time, if the linear motion guide device is small and light, the arrangement work of the rack members 64a and 64b does not take much time, but the linear motion guide device is a large one with a long guide distance. The work of arranging the rack members 64a and 64b after fixing the bed assembly 60 to the base (not shown) is very troublesome, and it is easy to assemble the linear motion guide device to a machine tool (table device or the like). is not. Further, even after the linear motion guide device is assembled, that is, after the rack members 64a and 64b are disposed, for example, when the bed mounting hole 60h formed in the bed 60 or the counterbore is large, the bed mounting hole of the rack member 64a. There is also a possibility that the part covering 60h or the counterbore is bent and easily deformed.

  The present invention has been made in order to solve such a problem, and its purpose is to assemble the slider, the rolling element and the cage without removing them even when the guide distance is long and the apparatus itself is enlarged. Provided is a linear motion guide device in which the guide rail can be firmly fixed to the base easily by a fixing member in the state, and the cage structure can be surely prevented by the gear structure. There is to do.

  In order to achieve such an object, the linear motion guide device of the present invention extends in a predetermined direction and is fixed to the base, and straddles the guide rail and extends along the extending direction. A reciprocating slider, a plurality of rolling elements incorporated between the guide rail and the slider and rolling in accordance with the movement of the slider, the rolling elements being held rotatably one by one, the rolling element And a cage that reciprocates along the guide rail as it rolls. In such a linear motion guide device, the guide rail is formed with a plurality of mounting holes that penetrate the guide rail and communicate with a fixing hole formed in the base and through which the fixing member is inserted. A rack gear extending along the rail is provided at a portion facing the slider, and the slider has a rack gear extending along the moving direction of the slider at the portion facing the guide rail, and the guide rail side rack gear. The cage is provided with the tooth profile portions opposed to each other, whereas the cage has a pinion gear that is interposed between the rack gear on the guide rail side and the rack gear on the slider side and meshes with each other. The rack gear on the guide rail side is positioned so as to avoid the mounting hole of the guide rail.

  In this case, the rack gear on the guide rail side may be provided along the guide rail on both sides of the mounting hole of the guide rail in a pair. Or while providing along the said guide rail to the both sides of the attachment hole of the said guide rail, it may be made to extend integrally avoiding the said attachment hole.

  Further, the rack gear on the guide rail side and the rack gear on the slider side may have a separate structure from the guide rail and the slider, and may be integrated with these by being attached to the guide rail and the slider.

The pinion gears form a pair and mesh with the guide rail side rack gear and the slider side rack gear provided along the guide rail on both sides of the guide rail mounting hole, and the pair of pinion gears. The rotation shafts of the gears are respectively interposed between the guide rail side rack gear and the slider side rack gear so that the rotation axes of the gears are positioned on the same axis.
At that time, the pair of pinion gears may be connected by a single shaft and rotated about the shaft.

  According to the linear motion guide device of the present invention, even when the guide distance is long and the device itself is enlarged, the guide rail can be easily fixed without removing the slider, rolling element and cage. The member can be firmly fixed to the base and the shift of the cage with respect to the slider can be reliably prevented by the gear structure.

Hereinafter, a linear guide apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings. The linear motion guide device of the present invention is assumed to be a finite stroke type in which the rolling element trajectory (stroke) is finite.
FIGS. 1A and 1B and FIGS. 2A and 2B show the configuration of the linear motion guide device according to the present embodiment. Such a linear motion guide device includes a guide rail 2 extending in a predetermined direction and fixed to a base (not shown), and a slider 4 straddling the guide rail 2 and reciprocating along the extending direction. And a plurality of rolling elements 6 incorporated between the guide rail 2 and the slider 4 and rolling as the slider 4 moves, and the rolling elements 6 are held rotatably one by one. And a cage 8 that reciprocates along the guide rail 2 as it rolls.

  The rolling element 6 can be used by arbitrarily selecting a ball or a roller (cylindrical roller, tapered roller, spherical roller, etc.) according to the purpose and condition of use of the linear motion guide device. Here, the case where the cylindrical roller is used as an example is assumed. Further, the size (diameter), shape and number of the rolling elements 6 can be arbitrarily determined according to the size and shape of the linear motion guide device (guide rail 2, slider 4 and cage 8), or the purpose and conditions of use thereof. Since it may be set, there is no particular limitation here.

  The guide rail 2 is formed with a flat upper guide surface 2a facing the slider 4 at the upper portion thereof, and both sides of the upper guide surface 2a are tapered and inwardly inclined. The direction guide surface 2b and the outward guide surface 2c inclined outward are formed so as to be thicker than the inward guide surface 2b. A transition surface 2d extending in a direction substantially perpendicular to the upper guide surface 2a is formed between the inward guide surface 2b and the outward guide surface 2c continuously from both guide surfaces 2b and 2c. Has been.

  Further, the guide rail 2 is communicated with a fixing hole formed in a base (not shown) through the guide rail 2 in the vertical direction (vertical direction in FIGS. 1 (a) and 1 (b)) to fix the guide rail 2 (not shown). A plurality of mounting holes 2h through which members (bolts as an example) are inserted are formed. In this case, a fixed number of fixing holes are formed in the base on a straight line along the longitudinal direction of the base at a predetermined interval (for example, an equal interval) and communicate with these fixing holes, respectively. As described above, the same number of mounting holes 2 h as the fixing holes are formed in the guide rail 2. In addition, a spiral groove (female screw portion) that is screwed with a spiral groove (male screw portion) of the bolt is cut in the inner peripheral portion of each fixing hole.

In the configuration shown in FIGS. 1A and 1B and FIGS. 2A and 2B, as an example, the mounting hole 2h extends in the extending direction of the guide rail 2 (the left-right direction in FIG. 2B). The guide rails 2 are arranged at predetermined intervals (as an example, at equal intervals) along the width direction of the guide rail 2 (the left-right direction in FIGS. 1A and 1B). Each mounting hole 2h is provided with a counterbore 2i for embedding a bolt head (not shown).
Then, bolts (not shown) are respectively inserted into the fixing holes (not shown) through these mounting holes 2h, and the male screw portions of the respective bolts are screwed with the female screw portions of the respective fixing holes, so that the guide rail 2 is fixed. It is fastened and fixed to a table (not shown).

  Here, the size and shape of the fixing hole (not shown) and the mounting hole 2h are not particularly limited because they may be arbitrarily set according to the size and shape of the fixing member (bolt), for example. In addition, the number of the fixing holes and the mounting holes 2h may be arbitrarily set according to the size of the linear guide device (for example, the length, width, and height of the guide rail 2). There is no particular limitation. In addition, as long as it forms so that a fixed hole and the attachment hole 2h can communicate, the fixed hole and the attachment hole 2h may not be the same number. Moreover, as a fixing member, as long as it is a member that can fix the guide rail 2 to a base (not shown), for example, a screw or a rivet may be applied in addition to a bolt.

  The guide rail 2 is provided with a rack gear (hereinafter referred to as a lower rack gear) 2g extending along the guide rail 2 on the upper guide surface 2a. The lower rack gear 2g is a fixing member (not shown). It is positioned so as to avoid the mounting hole 2h through which (as an example, a bolt) is inserted (so as not to cover the mounting hole 2h). At that time, the lower rack gear 2g has its tooth profile portion 2j facing upward, and faces the downward tooth profile portion 4j of a rack gear (upper rack gear) 4g provided on the downward slider surface 4a of the slider 4 described later.

  As an example, in FIGS. 1 (a) and 1 (b), a pair of lower rack gears 2g forms a pair, and the pair of lower rack gears 2g extends along the extending direction of the guide rail 2 to both sides of the mounting hole 2h. A configuration in which one is provided is shown. That is, the guide rail 2 has a pair (two) of the lower rack gears 2g with the upper guide surface 2a in a state where the mounting holes 2h are sandwiched from both sides in the width direction (left and right directions in FIGS. 1A and 1B). It becomes a structure arranged in.

According to such a structure, the lower rack gear 2g provided on the guide rail 2 does not block the mounting hole 2h, and even after the lower rack gear 2g is disposed on the guide rail, the guide rail 2 Bolts (not shown) can be respectively inserted into fixing holes (not shown) through the mounting holes 2h, and the guide rail 2 can be fastened and fixed to a base (not shown).
Further, since the lower rack gear 2g is positioned so as to avoid the mounting hole 2h (so as not to be applied to the mounting hole 2h), the lower rack gear 2g is bent and deformed after being disposed with respect to the guide rail 2. Can be avoided.

  In this case, as shown in FIG. 2 (b), the lower rack gear 2g is provided over the entire length (extending length) of the guide rail 2. That is, the total length (extension length) of the lower rack gear 2g is set to be the same as the total length (extension length) of the guide rail 2, but it is at least longer than the moving distance (stroke) of the slider 4. If there is, the total length (extension length) can be arbitrarily set.

  In the present embodiment, as an example, a pair of lower rack gears 2g are provided on both sides of the mounting hole 2h, but the mounting holes 2h of the guide rail 2 are avoided (the mounting holes 2h). As long as it is positioned, the lower rack gear 2g does not have a pair configuration as shown in FIGS. 1 (a) and 1 (b), but extends along the guide rail 2 to both sides of the mounting hole 2h. It is good also as a structure extended while being provided and avoiding the said attachment hole 2h integrally.

  For example, both ends of the guide rail 2 (upper guide surface 2a) in the width direction extend along the guide rail 2 and are connected to each other between adjacent mounting holes 2h to form a ladder shape. You may comprise a side rack gear. Alternatively, the lower rack gear may have a size that covers the entire upper guide surface 2a, and may have a perforated shape in which through holes are formed with the same size, shape, number, and spacing as the mounting holes 2h. In this case, only one through hole having a size covering all the mounting holes 2h may be formed.

  By adopting such an integrally extended configuration, the number of parts can be reduced, and not only can the cost of the linear motion guide device be reduced, but also the guide rail 2 (upper guide surface 2a). The lower rack gear can be easily arranged with respect to the guide rail 2 (upper guide surface 2a) without causing a shift in the tooth profile of the lower rack gear at both ends in the width direction.

  The lower rack gear 2g may have a separate structure from the guide rail 2, and may be configured to be attached to the guide rail 2 after the lower rack gear 2g is configured as a single separate part. On the other hand, a structure (integrated structure) integrated with the guide rail 2 may be obtained by performing processing (cutting, grinding, etc.) for forming the tooth profile portion 2j.

For example, in the case of a separate structure, if the lower rack gear 2g is formed of various resins, the manufacturing cost can be reduced, and the tooth profile portion 2j and the tooth profile portion 8j of the pinion gear 8g described later are provided. It is also possible to reduce the meshing sound that occurs when the meshes with each other. In this case, the lower rack gear 2g may be attached to the guide rail 2 by an arbitrary method such as fastening and fixing with various fastening members (bolts or the like), and joining and fixing by adhesion or welding.
On the other hand, in the case of an integral structure, since processing (cutting, grinding, etc.) for forming the tooth profile portion 2j can be performed directly on the guide rail 2, the guide rail 2 (lower rack gear 2g) The height can be suppressed, and the linear motion guide device can be made compact.

  The cage 8 has a cross-sectional shape that conforms to the outer shape of the guide rail 2 and extends along the extending direction of the guide rail 2. An inward holding portion 8b disposed opposite to the surface 2b and an outward holding portion 8c disposed opposite to the outward guide surface 2c are provided. Note that the inward holding portion 8b and the outward holding portion 8c are integrally connected to each other via a connecting portion 8d disposed to face along the transition surface 2d of the guide rail 2.

  The inward holding portion 8b and the outward holding portion 8c are integrally formed with a plurality of pockets 8p for holding a plurality of rolling elements (cylindrical rollers) 6 one by one, respectively. In this case, the pockets 8p are parallel to each other along the extending direction of the guide rail 2 (along the inward guide surface 2b and the outward guide surface 2c), and four rows are in phase with each other at equal intervals. Are arranged as follows. Further, the both inward holding portions 8b are connected to each other via a connecting portion 8a positioned along the upper guide surface 2a of the guide rail 2. According to such a configuration, the cage 8 becomes a structure that is integrally continuous over the entire region where the plurality of pockets 8p are arranged and along the extending direction of the guide rail 2.

  In this embodiment, as shown in FIGS. 1 (a) and 1 (b), a total of four rows (both sides) are provided on the cage 8 on both sides in the width direction (the left-right direction in the figure). The pockets 8p in the inward holding portion 8b and the outward holding portion 8c are each formed in a total of four rows), but the pocket configuration of the cage 8 is not limited to this. For example, the cage 8 may have a configuration in which two rows of pockets 8p are formed, one on each side in the width direction, or three or more pockets 8p on both sides. At this time, the pockets 8p may be arranged in parallel with each other along the extending direction of the guide rail 2 so that the columns are in phase with each other at equal intervals. Moreover, what is necessary is just to set arbitrarily the magnitude | size and shape of each pocket 8p according to the magnitude | size and shape of the rolling element 6. FIG.

  On the other hand, the slider 4 has a shorter length than the cage 8 and extends along the extending direction of the guide rail 2, and the inside thereof forms a shape along the outer shape of the cage 8. Specifically, on the inner side of the slider 4, a downward slider surface 4 a disposed to face the upper guide surface 2 a of the guide rail 2 and an inward surface disposed to face the inward holding portion 8 b of the cage 8. A slider surface 4b and an outward slider surface 4c arranged to face each other along the outward holding portion 8c are formed.

  The slider 4 is provided with a rack gear (hereinafter referred to as an upper rack gear) 4g extending along the moving direction of the slider 4 on the downward slider surface 4a, and the upper rack gear 4g has a tooth profile portion 4j. The lower rack gear 2g provided on the guide rail 2 is positioned so as to face the upward tooth profile portion 2j.

  As an example, in FIGS. 1A and 1B, a pair of upper rack gears 4g form a pair, and the pair of upper rack gears 4g are opposed to a pair of lower rack gears 2g provided on the guide rail 2. 1 shows a configuration in which one is provided. As a result, the rack gear structure in which each of the pair of lower rack gear 2g and upper rack gear 4g opposes each of the tooth profile portions 2j and 4j is extended to both sides of the mounting hole 2h of the guide rail 2 in the extending direction of the guide rail 2 In total, two sets are positioned along each line.

In this case, the upper rack gear 4g may be provided over the entire length (extension length) of the slider 4. That is, the total length (extension length) of the upper rack gear 4g may be set to the same length as the total length (extension length) of the slider 4.
Further, the ratio between the total length (extension length) of the slider 4 and the total length (extension length) of the cage 8 may be set according to the distance (slider stroke) by which the slider 4 is moved along the guide rail 2. Since it is good, it does not specifically limit here. However, since the moving distance of the cage 8 is half of the moving distance (slider stroke) of the slider 4, the length obtained by adding the distance of more than half of the slider stroke to the total length (extended length) of the slider 4 is 8 must be set.

  Furthermore, in the present embodiment, as an example, a pair of upper rack gears 4g is provided to be opposed to a pair of lower rack gears 2g provided on the guide rail 2 (two sets of rack gear structures). As long as the tooth profile portion 4j is positioned so as to face the tooth profile portion 2j of the lower rack gear 2g, the upper rack gear 4g may not have a pair configuration as shown in FIGS. 1 (a) and 1 (b).

  For example, only one upper rack gear may be disposed on the slider 4 (downward slider surface 4a) with a size covering the entire downward slider surface 4a of the slider 4. At this time, through holes may be formed in the upper rack gear with the same size, shape, number and interval as the mounting holes 2h, or one through hole having a size covering all the mounting holes 2h. You may form only.

  By adopting such an integrally extended configuration, the number of parts can be reduced, and not only can the cost of the linear motion guide device be reduced, but also the slider 4 (downward slider surface 4a) can be reduced. There is no deviation in the tooth profile of the upper rack gear at both ends in the width direction, and the upper rack gear can be easily disposed with respect to the slider 4 (downward slider surface 4a).

  The upper rack gear 4g may have a separate structure from the slider 4, the upper rack gear 4g may be configured as a separate component, and then attached to the slider 4, or the tooth profile portion 4j with respect to the slider 4 after molding. A structure (integrated structure) integrated with the slider 4 may be obtained by performing processing (such as cutting or grinding) for forming the.

For example, in the case of a separate structure, if the upper rack gear 4g is molded from various resins, the manufacturing cost can be reduced, and the tooth profile portion 4j and the tooth profile portion 8j of the pinion gear 8g described later It is also possible to reduce the meshing sound that occurs when the meshing. In this case, the upper rack gear 4g may be attached to the slider 4 by an arbitrary method such as fastening and fixing by various fastening members (bolts or the like), and joining and fixing by adhesion or welding.
On the other hand, in the case of an integral structure, the slider 4 (upper rack gear 4g) can be increased in height because the processing (cutting, grinding, etc.) for forming the tooth profile 4j can be performed directly on the slider 4. Therefore, the linear motion guide device can be made compact.

  Further, a pinion gear 8g that is interposed between the lower rack gear 2g provided on the guide rail 2 and the upper rack gear 4g provided on the slider 4 and meshes with each other is rotatably attached to the cage 8. Yes.

As an example, in FIGS. 1A and 1B and FIGS. 2A and 2B, a pair of pinion gears 8g forms a pair, and each of the pair of pinion gears 8g is a pair of lower rack gears. 2g and the upper rack gear 4g (two sets of rack gear structures), one pinion gear 8g so that the rotation shaft of each pinion gear 8g is positioned on the same axis line. A gear configuration (rack and pinion gear configuration) is shown in which the tooth profile portion 2j of the side rack gear 2g and the tooth profile portion 4j of the upper rack gear 4g are engaged with each other.
As a result, the pinion gear 8g is moved along the rack gears 2g and 4g, that is, on the guide rail 2 with the tooth profile portion 8j meshing with the tooth profile portions 2j and 4j of the lower rack gear 2g and the upper rack gear 4g. A structure that moves while rotating along.

  In this case, the pair of pinion gears 8g are connected by a single shaft 8s that is rotatably supported by the connecting portion 8a of the cage 8, and rotates about the shaft 8s as a rotation axis. Accordingly, since the two pinion gears 8g are connected to each other by the shaft 8s, handling when the pinion gear 8g is attached to the connecting portion 8a of the cage 8 is facilitated. The shaft 8s is rotatable by forming a support hole that penetrates the connecting portion 8a in the width direction (left and right direction in FIGS. 1A and 1B), for example, and inserting the shaft 8s through the support hole. Or may be rotatably supported by a bearing provided in the connecting portion 8a.

  Further, the shaft 8s may be fixed to the connecting portion 8a, and the two pinion gears 8g may be rotatably supported with respect to the shaft 8s, and each may be rotated independently, as described above. The shaft 8 may be freely rotatable, and the two pinion gears 8g may be fixed to the shaft 8s so as to be rotated simultaneously.

  Further, a cylindrical spacer 8t is interposed between the pair of pinion gears 8g, and these pinion gears 8g are configured to be rotatable while always maintaining a predetermined interval. At that time, the width of the spacer 8t (the distance in the left-right direction in FIG. 1A) is set to be substantially the same as the interval between the lower rack gear 2g and the upper rack gear 4g, and the inner diameter thereof is the radial dimension of the shaft 8s. It is set to be slightly larger than that and is inserted into the shaft 8s.

In addition, when it is set as the structure which rotates a pair of pinion gear 8g each independently, for example, even if the cage 8 is instantaneously distorted and the shaft 8s is inclined during operation of the linear motion guide device, the pinion gear 8g Since the pair of lower rack gears 2g and the upper rack gear 4g (two sets of rack gear structures) mesh independently, an increase in sliding resistance due to poor meshing can be effectively prevented.
On the other hand, when it is set as the structure rotated simultaneously, it is set as one structure (structure put together in one pinion gear) which set a pair of pinion gear 8g to the width | variety which can mesh simultaneously with two sets of rack gear structures. It becomes possible. As a result, the number of parts can be reduced, and the cost of the linear motion guide device can be reduced.

  In either case, the pair of pinion gears 8g are combined with one shaft 8s having higher rigidity than the cage 8 body (for example, the cage 8 body is made of a synthetic resin having excellent moldability and relatively high rigidity, and the shaft 8s is Further, the inclination of the pinion gears 8g can be suppressed by using a metal such as steel having high rigidity.

  In the configuration described above, the spacer 8t is interposed between the pair of pinion gears 8g as an independent component as shown in FIG. 1A, but the spacer 8t is integrated with the shaft 8s and the pinion gear 8g. It is good also as a structure. For example, the intermediate position of the shaft 8s may be increased in diameter by the size (outer diameter and width) of the spacer 8t.

Furthermore, in the present embodiment, as an example, a pair of pinion gears 8g is interposed between the pair of lower rack gears 2g and the upper rack gear 4g (two sets of rack gear structures). As long as the tooth profile portion 8j of the pinion gear 8g can mesh with the tooth profile portions 2j and 4j of both racks 2g and 4g, the number of pinion gears 8g to be interposed may not be one.
For example, two or more rack gear structures may be interposed. Further, the number of pinion gears 8g interposed in the rack gear structure (between rack gears 2g and 4g) positioned on one end side in the width direction and the pinion interposed in the rack gear structure (between rack gears 2g and 4g) positioned on the other end side The number of gears 8g may be different.

  In the present embodiment, as an example, the pinion gear 8g is attached at a substantially intermediate position in the extending direction of the cage 8. However, the attaching position is not necessarily the intermediate position, and any one of the extending directions. A pinion gear 8g may be attached to one side. Or you may make it provide the unit body which consists of a pair of pinion gear 8g, the shaft 8s, and the spacer 8t in two or more places spaced apart in the extension direction of the cage 8. FIG. When a plurality of pinion gears 8g are interposed in each rack gear structure (between each rack gear 2g and 4g), these pinion gears 8g may be attached to the cage 8 at predetermined intervals (for example, equal intervals).

  The material of the pinion gear 8g is not particularly limited. For example, the pinion gear 8g may be made of various resins (such as plastic) or metal depending on the materials of the lower rack gear 2g and the upper rack gear 4g that mesh with each other. (So-called drawing materials such as brass) may be used.

  Here, the size and shape of the rack and pinion gear structure (hereinafter referred to as the gear structure) constituted by the lower rack gear 2g and the upper rack gear 4g as described above and the pinion gear 8g meshing with each other are as follows. As long as the lower rack gear 2g is positioned so as not to engage with the mounting hole 2h of the guide rail 2, the rack gears 2g, 4g and the pinion gear 8g are mutually connected according to the size of the linear motion guide device. What is necessary is just to set relatively so that it can mesh | engage. At that time, the shape and height of the peaks, the shape and depth of the valleys, and the number and pitch of the peaks and valleys constituting the tooth profile portions 2j and 4j of the rack gears 2g and 4g and the tooth profile portion 8j of the pinion gear 8g, respectively. These may be set relatively so that they can be engaged with each other.

  Further, the number of such gear structures does not have to be a pair configuration in which one is disposed at each end in the width direction (left and right direction in the figure) as shown in FIGS. 1 (a) and 1 (b). The gear structure may be disposed only on one end side in the width direction.

  According to the configuration as described above, in the state in which the plurality of rolling elements (cylindrical rollers) 6 held in the cage 8 (each pocket 8p) are incorporated between the guide rail 2 and the slider 4, each rolling element. The (cylindrical roller) 6 moves while its rolling surface rotates between the inward guide surface 2b and the inward slider surface 4b and between the outward guide surface 2c and the outward slider surface 4c. In this case, when the slider 4 is moved along the guide rail 2, the linear motion is transmitted to the cage 8 via each rolling element (cylindrical roller) 6, and the cage 8 is transmitted along the guide rail 2 in the same direction. Move to. Accordingly, the slider 4 can be guided in a predetermined direction (the extending direction of the guide rail 2) and moved by a predetermined distance. The moving distance of the slider 4 at that time is twice the moving distance of the cage 8.

  On the other hand, when the cage 8 moves along the guide rail 2, the pinion gear 8g attached to the connecting portion 8a of the cage 8 is engaged with the lower rack gear 2g and the upper rack gear 4g, specifically, the tooth profile. It moves together with the cage 8 with the portion 8j meshing with the tooth profile portions 2j and 4j.

  Therefore, the slider 4 repeats reciprocating motion, and a minute slip occurs between the rolling element (cylindrical roller) 6 and the guide rail 2 and the slider 4 when the moving speed fluctuates or when the moving direction is changed. However, the cage 8 moves along the guide rail 2 because the pinion gear 8g meshes with the rack gears 2g and 4g and rotates. For this reason, the cage 8 can always be moved together with the rolling elements (cylindrical rollers) 6, and the relative position of the cage 8 with respect to the guide rail 2 and the slider 4 can be prevented from shifting. That is, the cage 8 can always be moved together with the guide rail 2 and the slider 4 while maintaining the position where it should be.

In addition, according to the present embodiment, even after the lower rack gear 2g is disposed with respect to the guide rail 2, the lower rack gear 2g provided on the guide rail 2 does not block the mounting hole 2h.
Therefore, the cage 8 holding the slider 4 and the rolling elements (cylindrical rollers) 6 is assembled, and the pinion gear 8g is interposed between the pair of lower rack gear 2g and upper rack gear 4g (two sets of rack gear structures). The tooth profile portions 2j, 4j, and 8j are meshed with each other, and the guide rail 2 integrated therewith (hereinafter, the guide rail 2 is referred to as a rail assembly) in this state with respect to a base (not shown) It can be fastened and fixed with bolts.

  That is, in such a rail assembly, the slider 4 and the cage 8 are appropriately moved along the guide rail 2 to expose the mounting hole 2h, and the bolt is inserted into the fixing hole of the base (not shown) from the mounting hole 2h and fastened. Can be made. And by performing the said fastening operation | work with respect to all the fixing holes, a rail assembly, ie, a linear motion guide apparatus, can be firmly fixed with respect to a base (not shown) with a volt | bolt.

  As described above, according to the linear motion guide device according to the present embodiment, the slider 4, the rolling element 6, and the cage 8 are assembled without being removed even when the guide distance is long and the device itself is enlarged. The guide rail 2 can be easily firmly fixed to a base (not shown) with bolts, and the shift of the cage 8 with respect to the slider 4 can be reliably prevented by the gear structure.

It is a figure which shows the structure of the linear guide apparatus which concerns on one Embodiment of this invention, Comprising: (a) is sectional drawing in the attachment position of a pinion gear (cross section along XX shown in FIG.2 (b)) (B) is a cross-sectional view of the pinion gear other than the mounting position (a cross-sectional view taken along line YY shown in the figure). BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structure of the linear motion guide apparatus which concerns on one Embodiment of this invention, Comprising: (a) is sectional drawing which shows the state which the rack gear and the pinion gear meshed, (b) is a linear motion guide apparatus. The partial cross section mechanism figure which shows the whole structure. It is a figure which shows the structural example of the conventional linear guide apparatus, (a) is a top view, (b) is a top view, (c) is a side view. It is a figure which shows the structural example of the conventional linear motion guide apparatus, Comprising: (a) is a half sectional view in the attachment position of a pinion gear, (b) is a bottom view of the whole apparatus, (c) is the whole apparatus. Top view.

Explanation of symbols

2 Guide rail 2a Upper guide surface 2g Lower rack gear 2h Mounting hole 2j Lower rack gear tooth profile 4 Slider 4a Down slider surface 4g Upper rack gear 4j Upper rack gear tooth profile 8 Cage 8g Pinion gear 8j Pinion gear tooth profile

Claims (6)

A guide rail that extends in a predetermined direction and is fixed to the base; a slider that straddles the guide rail and reciprocates along the extending direction; and is incorporated between the guide rail and the slider; A plurality of rolling elements that roll as the slider moves, and a cage that holds the rolling elements rotatably one by one and reciprocates along the guide rail as the rolling elements roll. A linear motion guide device,
The guide rail penetrates the guide rail and communicates with a fixing hole formed in the base, and has a plurality of mounting holes through which the fixing member is inserted, and extends along the guide rail. A rack gear is provided at a portion facing the slider, and a rack gear extending along a moving direction of the slider is opposed to the portion facing the guide rail, and the rack gear facing the guide rail side rack gear and the tooth profile portion of each other. On the other hand, the cage is rotatably mounted with a pinion gear that is interposed between the rack gear on the guide rail side and the rack gear on the slider side and meshes with each other. The linear guide device characterized in that the rack gear on the guide rail side is positioned so as to avoid the mounting hole of the guide rail.   The linear guide apparatus according to claim 1, wherein the rack gear on the guide rail side is provided along the guide rail on both sides of a mounting hole of the guide rail in a pair.   The rack gear on the guide rail side is provided along the guide rail on both sides of the mounting hole of the guide rail, and extends integrally so as to avoid the mounting hole. The linear motion guide apparatus according to 1.   The guide rail-side rack gear and the slider-side rack gear form a separate structure from the guide rail and the slider, and are integrated with the guide rail and the slider by being attached thereto. The linear motion guide device according to any one of claims 1 to 3.   The pinion gears form a pair and mesh with the guide rail side rack gear and the slider side rack gear provided along the guide rail on both sides of the mounting holes of the guide rail, and the pair of pinion gears The linear motion guide according to any one of claims 2 to 4, wherein the rotary shafts are respectively interposed between the guide rail side rack gear and the slider side rack gear so that the rotary shafts are positioned on the same axis. apparatus.   The linear motion guide device according to claim 5, wherein the pair of pinion gears are connected by a single shaft and are rotated around the shaft.

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