JPH07127639A - Direct-acting rolling guide unit - Google Patents

Abstract

PURPOSE:To provide a direct-acting rolling guide unit which can deal with both for an upper fitting type or a lower fitting type in order to fix a track rail to a base. CONSTITUTION:In this direct-acting rolling guide unit, a threaded part 28 is formed on the inner face of the small diameter part 25 of a hole part for a shank of the fitting hole 15 of a fitting 2, a bolt inserted from the base 20 side is threadedly engaged with the threaded part 28 so as to fix the track rail 2 to the base 20, and hence it corresponds with a lower fitting type. A hole part 27 for a embedded plug is formed on the upper end part of the hole part 26 for the head of the fitting hole 15, and the embedded plug 13 is press- fitted in the hole part 27, so as to prevent invasion of dust and water content in the fitting hole 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motion rolling guide unit which is applied to various devices such as machine tools, precision machining devices, and test devices, and in which a slider reciprocates on a track rail.

[0002]

2. Description of the Related Art Conventionally, there is a linear motion rolling guide unit disclosed in Japanese Patent Laid-Open No. 5-138428. The linear motion rolling guide unit will be described with reference to FIGS. 3 and 4. FIG. 3 is a partially broken perspective view showing an example of a conventional linear motion rolling guide unit, and FIG. 4 is a front view of an end cap incorporated in the linear motion rolling guide unit of FIG.

In a conventional linear motion rolling guide unit, track grooves 5 are formed on both side wall surfaces 22 of the track rail 2 in the longitudinal direction, and a slider 1 is straddled on the track rail 2 so that the slider 1 can reciprocate. As will be described later, a plurality of mounting holes 15 are formed in the track rail 2 at intervals in the longitudinal direction. Bolts are inserted through these mounting holes 15, and the track rails 2 are fixed to the base 20 such as a bed, a machine stand, and a work table by the bolts. In addition, a plug 13 is fitted in the upper part of the mounting hole 15 so that dust, water, etc., do not enter after the bolt is inserted.

The slider 1 is movable relative to the track rail 2 and each track groove 5 of the track rail 2.
A casing 3 having a raceway groove 9 formed at a position facing each other, rolling elements 7 such as a large number of balls rolling between the opposite raceway grooves 5, 9 and end caps 6 attached to both ends of the casing 3, respectively. is doing. A plurality of screw holes 34 for attaching the slide table 4 are formed in the upper portion of the casing 3. Rail insertion recesses 10 are formed on the lower surfaces of the casing 3 and the end cap 6 so that the casing 3 and the end cap 6 move across the track rail 2. In addition, in order to prevent the rolling elements 7 from falling out of the casing 3, the holding band 18 surrounds the many rolling elements 7 so that the casing 3
Mounted on the underside of the slider 1 to achieve a seal between the track rail 2 and the lower end of the casing 3.

As shown in FIG. 4, the end cap 6 has a raceway groove 39 which forms a sliding surface between the rolling element 7 and the track rail 2 and a direction of the rolling element 7 for circulation of the rolling element 7. A turning path 11 for turning is formed on both sides. Further, as shown in FIG. 3, a side surface seal 17 for achieving a seal between the track rail 2 and both ends of the slider 1 in the longitudinal direction is attached to the end cap 6, and a space between the track rail 2 and the slider 1 is attached. A grease nipple 30 for supplying a lubricant is attached to the sliding surface of the. The end cap 6 has a plurality of mounting holes 31.
It is attached to both end surfaces of the casing 3 by screws 32 penetrating the casing.

This linear motion rolling guide unit is constructed as described above, and mounts the slider 1 in a state of straddling the track rail 2 and circulates along the track groove 5 of the track rail 2 into a plurality of rolling members. The moving body 7 slides freely. The rolling elements 7 in the load region running in the track groove 5 of the track rail 2 are guided to the direction change path 11 formed in the end cap 6 shown in FIG. 4, and then parallel to the track groove 9 in the upper part of the casing 3. Return passage hole 12 formed by
, And a large number of rolling elements 7 endlessly circulate in the infinite circulation path. Thus, the rolling of the loaded rolling element 7 located between the raceway groove 9 formed in the slider 1 and the raceway groove 5 formed in the track rail 2 causes the track rail 2 and the slider 1 to move relative to each other. You can exercise.

FIG. 5 is a perspective view showing an example of use of a conventional linear motion rolling guide unit. In FIG. 5, parts having the same purpose as parts of FIGS. 3 and 4 are given the same reference numerals. As shown in FIG. 5, the linear motion rolling guide unit includes the base 2
0, track rails 2 are fixed in parallel in two rows, a plurality of slide units, that is, sliders 1 are straddled on each track rail 2, a slide table 4 is fixed on the sliders 1, and the slide table 4 is mounted on the slide table 4. The relatively heavy devices described above are moved forward and backward with high accuracy over a relatively long distance.

In the linear motion rolling guide unit shown in FIG. 5, the orbits and the rolling elements are moved vertically through the slider 1 and
Since it is necessary to support a radial load and a moment load in each of the left and right directions, they are engaged in a state where the internal clearance is zero or a preload is applied. Since this linear motion rolling guide unit has the above-mentioned configuration, if there is an error in the parallelism of the track rail 2, the sliding load of the slider 1 increases, the service life of the guide unit decreases, and the sliding resistance increases. Change occurs, resulting in a serious influence on accuracy and performance. For this reason, not only the number of assembling steps for improving the accuracy of the parallelism of the track rail 2 is significantly increased, but also with a high accuracy of several tens of μm or less over the entire length of the track rail 2 having a length of several meters. Fixing the track rails 2 in parallel is a difficult task that is almost impossible.

The track rail 2 shown in FIG. 3 is provided with a mounting hole 15 penetrating from the upper surface 19 to the lower surface used for fixing to the base 20. As shown in FIG. 6, the mounting hole 15 includes a head hole portion 26 into which a head 36 of a bolt 16 formed on the track rail 2 is fitted,
A bolt 1 formed concentrically at the bottom of the head hole 26.
6 and a small diameter hole portion 25 through which the shank 35 is inserted. First, the mounting hole 15 is used when the track rail 2 is polished. That is, as shown in FIG. 8, the track rail 2 has a mounting hole 1 for the track rail 2.
The bolt 16 inserted in the screw 5 is screwed into the screw hole 33 formed in the processing table 37 and fixed to the processing table 37. The track rail 2 fixed to the processing table 37 has a grindstone 38 arranged on the upper side of the track rail 2 and on both sides in the longitudinal direction.
Thus, the upper surface 19 of the track rail 2 and the longitudinal side wall surfaces 22, 22 are totally polished at one time.

When fixing the track rail 2 to the bed 20, as shown in FIG.
Is a screw hole 21 in which the mounting hole 15 is formed in the base 20.
Then, the bolt 16 is inserted into the mounting hole 15 from above and is screwed into the screw hole 21 to be fixed to the base 20. In this case, the bolts 16 inserted into the mounting holes 15 formed in the track rail 2 are used to fix the track rail 2
Is fixed to the upper surface of the head of the bolt 16,
Since the remaining concave portion of the mounting hole 15 is formed, the embedding plugs 13 and 23 are embedded in the concave portion as shown in FIGS. 3 and 7.

Mounting hole 15 formed in the track rail 2
As a means for burying the plug 13 in the recess, conventionally, a filler such as a resin material, a copper material, or an aluminum alloy material is filled in the recess, or as disclosed in JP-A-5-138428. The molded plug 23 with the air vent hole 29 is fitted in the recess formed above the mounting hole 15 (see FIG. 7). Furthermore, the plug 23 provided as described above
When the upper surface of the plug 23 projects from the upper surface 19 of the track rail 2, the protruding portion of the plug 23 is ground so that the upper surface of the plug 23 is flush with the upper surface 19 of the track rail 2.

[0012]

However, recently, as described above, from the upper surface 19 of the track rail 2 to the bolt 16
Not only the mounting method for fixing the track rail 2 to the base 20 (hereinafter referred to as an upper mounting type), but also the mounting method for fixing the track rail 2 to the base 20 by inserting a bolt from the base 20 side (hereinafter, There is a lot of requests for "mounting under." As a countermeasure to meet the demand, there is a method of forming a female screw into which a bolt is screwed on the lower side of the track rail 2 and screwing the bolt 16 into the female screw from the base 20 side to fix the track rail 2 to the base 20. Conceivable. However, in such a structure, it is necessary to separately provide a means for fixing the track rail 2 to the base such as the processing table 37 when the track groove, the upper surface and the like of the track rail 2 described above are totally polished. The problem arises.

Therefore, an object of the present invention is to solve the above problems, and is used for fixing the track rail to the base when polishing the track groove, the upper surface, etc. of the track rail, and the upper surface of the track rail. It is possible to use it for the lower mounting type by simply forming the plugging hole and mounting screw in the upper mounting type mounting hole used to fix the track rail to the base by inserting the bolt from An object of the present invention is to provide a linear motion rolling guide unit capable of ensuring strength and reducing costs.

[0014]

In order to achieve the above object, the present invention is configured as follows. That is,
According to the present invention, a track rail provided with a plurality of mounting holes formed vertically on both sides in the longitudinal direction and a plurality of mounting holes penetrating in the vertical direction so as to be fixed to a base, and facing the track groove. Having a casing having a raceway groove and end caps attached to both end faces of the casing, and having a slider reciprocating over the track rail, and a rolling element rolling between the raceway grooves. In the linear motion rolling guide unit, the mounting hole has a shank hole portion into which a shank of a bolt is inserted, a head hole portion in which the head of the bolt is arranged, and an embedding plug formed at an upper end portion of the head hole portion. Is formed in the shank hole, a mounting screw is formed in the shank hole, and the diameter of the shank hole is larger than the diameter of the head hole. To form a support surface for the embedding plug, and the upper surface of the embedding plug is formed flush with the upper surface of the track rail in a state of being disposed in the embedding hole portion. Regarding the rolling guide unit.

Further, in this linear motion rolling guide unit, the plug is made of an aluminum alloy.

Further, in this linear motion rolling guide unit, the embedding hole portion in the mounting hole is formed to be shallower than the head hole portion.

In this linear motion rolling guide unit, when the bolt is inserted into the mounting hole from the upper surface of the track rail to mount the track rail on the base, the screw diameter of the bolt is the shank. It is smaller than the diameter of the mounting screw of the working hole.

In this linear motion rolling guide unit, when the bolt is inserted from the base side to attach the track rail to the base, the screw of the bolt is the attachment screw of the shank hole portion. Is screwed to.

[0019]

The linear motion rolling guide unit according to the present invention is constructed as described above and has the following actions. That is, in this linear motion rolling guide unit, a mounting hole for mounting a track rail on a base has a shank hole into which a shank of a bolt is inserted, a head hole in which a head of the bolt is arranged, and a hole for the head. Since it is composed of an embedding hole portion in which an embedding plug formed at the upper end of the section is arranged and a mounting screw is formed in the shank hole portion, for processing the track groove, the upper surface, etc. of the track rail. When the track rail is mounted on a base such as a processing table, a bolt smaller than the diameter of the mounting screw can be inserted into the mounting hole from the upper surface side of the track rail to fix the track rail to the base. With the track rail fixed to the base, the upper surface of the track rail and the both side wall surfaces in the longitudinal direction can be subjected to a total polishing process at one time by the grindstones arranged above the track rail and on both sides in the longitudinal direction.

In addition, after the track rail is completely polished, the bolts are inserted into the mounting holes from the upper surface of the track rail to mount the track rail on the base such as a bed or machine base. The track rail can be fixed to the base by screwing the bolt into a screw formed in the base.
Alternatively, when the track rail is attached to the base by inserting the bolt from the base side, the screw of the bolt is screwed into the attachment screw of the shank hole portion to attach the track rail. It can be fixed to the base. That is, this linear motion rolling guide unit can be adapted to either a lower mounting type or an upper mounting type when the track rail is mounted on the base.

Further, the diameter of the embedding hole is made larger than the diameter of the head hole to form a support surface of the embedding, and the embedding is arranged in the embedding hole. Therefore, even if the track rail is fixed to the base by the upper mounting type or the lower mounting type, the embedding plug can be reliably and stably arranged in the embedding hole portion of the track rail. In addition, the track rail can embed the embedding plug in the embedding hole portion, and can grind the upper surfaces of the track rail and the embedding plug as necessary, and the upper surface of the embedding plug can be an upper surface of the track rail. Since it can be ground on the same surface, foreign matter such as dust and dust does not accumulate in the mounting hole, and when the slider is mounted on the track rail, the sealing performance between the track rail and the side seal is improved. Can be made.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a linear motion rolling guide unit according to the present invention will be described below with reference to FIG. FIG. 1 is a sectional view showing an embodiment of a linear motion rolling guide unit according to the present invention. This linear motion rolling guide unit is shown in FIGS.
Also, since it has basically the same configuration as the conventional linear motion rolling guide unit shown in FIG. 5, parts having the same operation as parts shown in FIGS. is doing.

In this linear motion rolling guide unit, a shank hole portion 25 of a mounting hole 15 through which a bolt (not shown) for fixing the track rail 2 to the base 20 is inserted, and a head hole of the mounting hole 15. Plug 1 formed on the upper part of the portion 26
It is characterized by the embedding hole 27 and the embedding plug 13 into which 3 is press-fitted. This linear motion rolling guide unit is, similar to that shown in FIG. 3, a track rail 2 provided with track grooves 5 on both side wall surfaces 22 in the longitudinal direction, and a track rail 2 which extends over the track rail 2 and faces the track rail 2. The slider 1 is slidable. Similar to that shown in FIG. 3, the slider 1 in this linear motion rolling guide unit has a casing 3 having a raceway groove 9 formed at a position facing the raceway groove 5 of the track rail 2, and a space between the opposing raceway grooves 5 and 9. It has rolling elements 7 such as balls that can roll and move relative to each other, and end caps 6 attached to both ends of the casing 3 in the sliding direction, that is, the longitudinal direction.
It has a side seal 17 and a bottom seal 8 to achieve a seal between the casing and the casing 3.

The linear motion rolling guide unit is provided with a mounting hole 15 penetrating from the upper surface 19 to the lower surface of the track rail 2. As shown in FIG. 1, the mounting hole 15 has three holes.
The holes having the inner diameters of different types are formed so as to be concentric with each other, and the lower holes have smaller diameters. That is, the shank hole portion 25 having the smallest diameter is formed on the lowermost side of the mounting hole 15, and the inner surface of the shank hole portion 25 is a base for fixing the track rail 2 to the base 20 by a bottom mounting method. A female screw, that is, a mounting screw 28, into which the bolt 16 inserted from the 20 side is screwed, is formed. A head hole 26 is formed above the shank hole 25, and the track rail 2 is fixed to the working table 37 (FIG. 8) when the track rail 2 is totally polished. Therefore, the head 36 of the bolt 16 inserted from above the track rail 2 is fitted.

An embedding hole portion 27 is formed at the upper end of the head hole portion 26, and the hole diameter of the embedding hole portion 27 is larger than that of the head hole portion 26. In addition, a step portion formed at the boundary between the plug hole 27 and the head hole 26 is formed on the support surface 40 of the plug 13. Further, a step portion formed at the boundary between the head hole portion 26 and the shank hole portion 25 is formed on the support surface 42 of the head of the bolt. The plug 13 is press-fitted into the plug hole 27 to close it. As shown in FIG. 1, the shank hole portion 25, the head hole portion 26, and the embedding hole portion 27 in the mounting hole 15 are formed such that the depth of each hole is larger as the diameter is smaller. .

In this linear motion rolling guide unit, when the bolt is inserted from the upper surface 19 of the track rail 2 into the mounting hole 15 to fix the track rail 2 to the base 20, the screw of the bolt is By using a screw having a diameter smaller than that of the mounting screw 28 of the shank hole 25, the bolt can be inserted into the shank hole 25 and the bolt is screwed into the screw formed in the base 20. Thus, the track rail 2 can be fixed to the base 20. Further, in the case of the lower mounting type in which the bolt is inserted from the base 20 side to fix the track rail 2 to the base 20, the screw of the bolt can be screwed into the mounting screw 28 of the shank hole 25. By using the bolt, the track rail 2 can be fixed to the base 20 by inserting the bolt from the side of the base 20 and screwing the bolt into the mounting screw 28 of the shank hole 25.

The embedding plug 13 shown in FIG. 1 is a plate-like member having a slightly larger inner diameter than the embedding hole portion 27 to be press-fitted and having a tightening margin. It has the same thickness or a slightly thicker shape. The material of the plug 13 may be the same material as the casing, aluminum alloy, brass, copper, resin, rubber or the like, but it is superior in terms of cost and durability to manufacture the plug 13 from the aluminum alloy. Is the most preferable one. After press-fitting the plug 13 into the plug hole 27, the top surface 19 of the track rail 2 and the top surface 41 of the plug 13 are arranged such that the top surface of the plug 13 is flush with the top surface 19 of the track rail 2. Is ground and polished.

Another embodiment of the linear motion rolling guide unit according to the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a track rail having a mounting hole for fixing the track rail 2 to the base 20. The track rail shown in FIG. 2 has the same configuration as the track rail shown in the embodiment of FIG. 1 except that the depth of the embedding hole 27 and the shape of the embedding 23 are different. Are given the same reference numerals. In this embodiment, the plugging hole 2 shown in FIG.
7 is formed deeper than the embedding hole portion 27 shown in FIG. 1, and the embedding plug 23 has an annular leg portion 24 formed around the plate-shaped body. Since the embedding hole 27 is formed deep and the annular leg 24 is provided around the embedding 23, the contact area between the embedding 23 and the inner surface of the embedding hole 27 increases, so that the vibration is reduced. The plug 2 that is press-fitted into the plug hole 27 due to the above reasons
There is no possibility that 3 will project above the track rail 2 from the embedding hole 27.

Although not shown, the plugs 13 and 23 are also provided.
The wall surfaces of the embedding plugs 13 and 23 may be formed in a tapered surface so that they can be easily press-fitted, and the wall surface of the embedding plug hole portion 27 may be formed in a tapered shape that is expanded upward correspondingly. Alternatively, the peripheral edge of the embedding plug 13 on the side where the embedding plug hole portion 27 is press-fitted may be rounded or tapered to facilitate press-fitting the embedding plug 13 into the embedding hole portion 27.

In the linear motion rolling guide unit according to the present invention, the method for fixing the track rail 2 to the base 20 by the above-mentioned mounting method using the mounting screw 28 formed in the shank hole portion 25 of the track rail 2 is the track. Similar to the case where the rail 2 is attached to the processing table 37, after fixing the bolts to the base 20, the embedding hole portions 13 and 23 are press-fitted into the embedding hole portion 27 so as to be pressed above the head of the bolt. , The upper surfaces 41 of the plugs 13 and 23 on the track rail 2
It may be ground so as to be flush with the upper surface 19 of.

Further, the track rail 2 in this linear motion rolling guide unit can be fixed to the base 20 by a bottom mounting method. At this time, the plugs 13 and 23 are embedded in the plug hole 27 in advance at a factory or the like,
The upper surface 41 of 23 can be ground so as to be flush with the upper surface 19 of the track rail 2. The track rail 2 in this state is arranged on the base 20, the bolt is inserted from the base 20 side using the screw 28 formed in the shank hole 25, and the screw of the bolt is attached to the mounting screw 28.
It can be attached by screwing into. Alternatively, the track rail 2 can be fixed to the base 20 by a bottom mounting method without using the mounting screw 28 formed in the shank hole portion 25. For example, although not shown, the head hole 26 is formed in a non-circular shape, the nut mounted in the head hole 26 is prevented from rotating, and the bolt inserted into the shank hole 25 from the base 20 side is a nut. It is also possible to fix the track rail 2 to the base 20 in a bottom-mounted manner by screwing the track rail 2 into the base rail 20.

[0032]

The linear motion rolling guide unit according to the present invention is constructed as described above and has the following effects. That is, in this linear motion rolling guide unit, a mounting screw is formed on the inner surface of the shank hole portion of the mounting hole formed in the track rail, and a plugging hole portion is formed at the upper end of the head hole portion of the mounting hole. Therefore, the track rail can be fixed to the base by any of the upper mounting type and the lower mounting type, and moreover, the track groove of the track rail,
Even when the upper surface or the like is ground, the track rail can be fixed to the work table by using the mounting screw formed in the mounting hole.

That is, in the case of the top mounting type, by using the bolt having a screw diameter smaller than that of the mounting screw of the shank hole, the track rail is mounted on the track rail with respect to the base. The track rail can be fixed by screwing the track rail into the screw of the base by inserting the bolt from the upper surface into the mounting hole. Further, in the case of the bottom mounting type, by using the bolt having a screw to be screwed into the mounting screw of the shank hole portion, the bolt is inserted from the base side to use the bolt for the shank. It can be screwed and fixed to the mounting screw of the hole.

Further, in the rail of this linear motion rolling guide unit, the upper surfaces of the track rail and the plug can be ground / polished as necessary after the plug is press-fitted into the press-fitting portion. The upper surface of the plug can be made flush with the upper surface of the track rail, and a good sealing state can be ensured between the upper surface of the track rail and the side surface seal provided on the slider, and Since there is no step on the upper surface of the track rail, foreign matter such as chips falling on the upper surface of the track rail does not enter the slider. Also, when the plug is made of an aluminum alloy, there is no step on the upper surface of the track rail,
The sliding property of the side seal of the slider with the rubber seal member is good, the wear resistance of the side seal can be improved, and the life can be extended.

Conventionally, the depth of the recess was not constant because a plug was embedded in the remaining recess of the mounting hole formed above the head upper surface of the bolt inserted into the mounting hole of the track rail. In the rolling guide unit, the embedding hole portion is formed at the upper end of the head hole portion of the mounting hole,
Since the embedding plug is configured to be press-fitted into the embedding hole, it is easy to dimension the embedding hole and the embedding plug, and the embedding plug can be securely inserted into the embedding hole. Can be firmly set.

Further, in this linear motion rolling guide unit,
A female screw is formed on the inner surface of the shank hole portion of the mounting hole of the existing track rail, and a plugging hole portion is formed at the upper end of the head hole portion of the mounting hole and is embedded in the plugging hole portion. Since the above effect can be achieved by press-fitting the plug, the conventional linear motion rolling guide unit can be configured with the track rail being attached downward with a simple modification.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a track rail in a linear motion rolling guide unit according to the present invention.

FIG. 2 is a sectional view showing another embodiment of the track rail in the linear motion rolling guide unit according to the present invention.

FIG. 3 is a partially cutaway perspective view showing a conventional linear motion rolling guide unit.

FIG. 4 is a front view showing an end cap of the linear motion rolling guide unit of FIG.

FIG. 5 is a perspective view showing an example of a conventional linear motion rolling guide unit.

FIG. 6 is a sectional view showing an example of a track rail in a conventional linear motion rolling guide unit.

FIG. 7 is a cross-sectional view showing an example of a plug in a conventional linear motion rolling guide unit.

FIG. 8 is a cross-sectional view showing an example of a polishing method for polishing a rail of a conventional linear motion rolling guide unit.

[Explanation of symbols]

 1 Slider 2 Track rail 3 Casing 5, 9 Raceway groove 6 End cap 7 Rolling element 13, 23 Plug 15 Mounting hole 19 Track rail upper surface 20 Base 22 Longitudinal side wall surface 24 Plug's annular leg 25 Shank hole 26 head hole 27 plug hole 28 screw 38 grindstone

Claims (5)

[Claims] 1. A track rail having a plurality of mounting holes formed vertically on both sides in the longitudinal direction and a plurality of mounting holes penetrating in the vertical direction for fixing to the base and spaced apart in the longitudinal direction. A slider having a casing having opposing raceway grooves and end caps attached to both end faces of the casing and reciprocating over the track rail; and a rolling element rolling between the raceway grooves. In the linear motion rolling guide unit, the mounting hole has a shank hole portion into which a shank of the bolt is inserted, a head hole portion in which the head of the bolt is arranged, and a buried portion formed at an upper end portion of the head hole portion. The shank hole is provided with a mounting screw, and the diameter of the embedding hole is larger than the diameter of the head hole. form And a support surface for the embedding plug is formed, and an upper surface of the embedding plug is formed on the same surface as an upper surface of the track rail in a state of being disposed in the embedding plug hole portion. Rolling guide unit. 2. The linear motion rolling guide unit according to claim 1, wherein the plug is made of an aluminum alloy. 3. The linear motion rolling guide unit according to claim 1, wherein the embedding hole portion in the mounting hole is formed to be shallower than the head hole portion. 4. When the bolt is inserted into the mounting hole from the upper surface of the track rail to mount the track rail to the base, the diameter of the screw of the bolt is the mounting screw of the shank hole portion. The linear motion rolling guide unit according to claim 1, wherein the linear motion rolling guide unit has a diameter smaller than the diameter. 5. When the bolt is inserted from the side of the base to attach the track rail to the base, the screw of the bolt is screwed into the attaching screw of the shank hole. The linear motion rolling guide unit according to claim 1.