BACKGROUND ART Generally, a linear motion guide is called as a linear bearing, a straight line bearing, a linear movement guide apparatus, etc. and is directed to guiding and supporting a linear movement (including a reciprocating movement). Recently, a rail member is bent for thereby implementing a curve movement (rotational movement).

As an example of a conventional linear motion guide, there is a linear motion guide having the Korean Patent No. 246985. An apparatus for fabricating a linear motion guide is disclosed in the Korean Patent No. 246986. According to the above patents, a fixing method of a rail member is implementing using a plastic deformation. In a state that a rail rod member is inserted in a groove, a groove is formed in a portion near the rod member and is plastically deformed. In this case, the rod member is not escaped by an engaging shoulder for thereby fixing the rod member.

DISCLOSURE OF THE INVENTION Accordingly, it is an object of the present invention to provide a linear motion guide which overcomes the problems encountered in the conventional art.

It is another object of the present invention to provide a linear motion guide

which is capable of preventing a transformation of a rod member or a frame when assembling a rod member.

In order to achieve the above object, there is provided a linear motion guide according to a first embodiment of the present invention which includes a track rail which includes a rail groove in which a rod member is positioned and a track rail having an engaging shoulder portion for preventing the rod member from being escaped from the rain groove, and a carrier moved along the track rail in a linear motion guide for guiding a linear movement, wherein said track rail includes a rod member, a frame member, a support engaged with the frame member and a rail groove in which the rod member is engaged as the frame member and the support are engaged.

In order to achieve the above object, there is provided a linear motion guide according to a second embodiment of the present invention which includes a bottom surface contacting with a flat upper surface of the support, a lateral surface having a certain angle with respect to the bottom surface, a channel extended at a corner potion between the bottom surface and the lateral surface in a longitudinal direction, the rod member being inserted into the channel, and an engaging shoulder portion extended from the lateral surface and covering a part of the channel in a lateral direction in a linear motion guide which includes a rail groove for setting a rod member therein, a track rail in which the rod member is engaged, and a carrier moving along the track rail.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become better understood with reference to the accompanying drawings which are given only by way of illustration and thus are not

limitative of the present invention, wherein : Figure 1 is a perspective view illustrating a linear motion guide according to an embodiment of the present invention; Figure 2 is a cross sectional view illustrating a linear motion guide taken along line A-A of Figure 1; Figure 3 is a side view illustrating each element of a track rail of a linear motion guide of Figure 1 by disassembling each element; Figure 4 is a perspective view illustrating a linear motion guide according to another embodiment of the present invention; Figures 5A and 5B are views illustrating a track rail of a linear motion guide according to another embodiment, of which: Figure 5A is a perspective view of the same; and Figure 5B is a cross sectional view taken along line B-B; and Figure 6 is a perspective view illustrating a track rail of a linear motion guide according to still another embodiment of the present invention; Figures 7A and 7B are views illustrating a track rail of a linear motion guide according to still another embodiment, of which: Figure 5A is a perspective view of the same; and Figure 5B is a cross sectional view of the same; and Figure 8 is a perspective view illustrating a track rail of a linear motion guide according to further still another embodiment of the present invention; Figure 9 is a cross sectional view illustrating a track rail of a linear motion guide according to further still another embodiment of the present invention; and Figures 10A and 10B are views illustrating a track rail of a linear motion guide according to another embodiment, of which:

Figure 10A is a cross sectional view of the same; and Figure 10B is a perspective view of the same.

MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS The embodiments of the present invention will be explained with reference to the accompanying drawings.

Figure 1 is a perspective view illustrating a linear motion guide 10 according to the present invention. As shown therein, a track rail of the linear motion guide 10 is extended at a certain depth. Figure 2 is a cross sectional view of the linear motion guide 10. Figure 3 is a side view illustrating members which form the track rail 20.

As shown in Figures 1 through 3, the linear motion guide 10 according to the present invention includes a track rail 20 and a carrier 40. The track rail 20 includes a frame member 22, a support member 24, and a rail rod member 30. The frame member 22 and the support member 24 are formed in a longitudinal rod shape. A rail groove 28 is formed in a length direction based on an engagement of the frame member 22 and the support member 24. A part of the cross section of the rail groove 28 forms a part of a circle. A rod member 30 is engaged to the rail groove 28.

The frame member 22 and the support member 24 are formed based on an injection using a metallic material such as a common aluminum or a structural aluminum alloy, etc. In order to implement a linear structure, the frame member 22 and the support member 24 may be fabricated based on a plastic working and hot drawing. The frame may have various profiles based on the application of the same including the shape of Figure 1.

A cylindrical rod member (referred to as a shaft) 30 is engaged into the rail

groove 28. As shown in Figure 2, the region of more than half of the rod member 30 is inserted into the rail groove 28 and a part of the circular portion is exposed (protruded). The rod member 30 is not easily escaped from the rail groove 28 due to an engaging shoulder portion of the rail groove 28 or an entrance narrowed due to the engaging shoulder portion (smaller than the radius of the rod member 30). The rod member 30 is formed of a metallic material such as bearing steel, stainless steel, structural carbon steel, etc. and is fabricated based on a heat treatment and precision grinding.

In order to prevent the rod member 30 from being escaped, the engaging shoulder portion 29 is formed at the entrance. in order to assembly the rod member 30, the rod member 30 may be pressed and inserted. In this case, the rod member 30 may be deformed, and a shape precision may be degraded due to the deformation of the rod member 30. Therefore, in the present invention, the frame is divided into the frame member 22 and the support member 24, and the rail groove 28 is formed based on an engagement of the frame member 22 and the support member 24.

In the embodiments of Figures 1 through 3, a groove is not formed in the support member 24, and the rod member 30 contacts with an upper surface. The frame member 22 includes a channel 32 formed in a longitudinal direction. As shown in Figure 3, the channel 32 includes a straight line portion 32a which is extended in the vertical direction and has the same length as the radius of the rod member, a first circular portion 32b corresponding to 1/4 of the circle (90°) and a second circular potion 32c which forms the engaging shoulder portion 29. The radius of the circular portion is the same as the radius of the rod member or is larger than the same. In the above described construction, the rod member 30 may be

inserted from the bottom of the frame member 22. When the upper surface of the support member 24 is covered, the rod member 30 is not escaped in the lateral direction. As a result, the channel 32 and a part of the upper surface of the channel forms a rail groove.

The carrier 40 includes a carrier block 42, a track roller bearing 44, and an engaging member 46. The carrier block 42 includes a screw hole 42b formed at both edge portions and used for engaging a linear transfer element (not shown). As shown in Figure 1, three engaging portions 42a are formed in the carrier block 42 at both sides. In the present invention, the above described construction is not limited.

More than four engaging portions 42a may be formed.

The track roller bearing 44 includes an outer wheel. The outer surface of the outer wheel (contacting with the rod member) is V-grooved. Therefore, the rod member 30 and the outer surface 44a contact each other at two points. A groove 44b is formed in an inner side of the V-shaped outer surface 44a in a ring shape and surrounds the outer wheel. A lubricant may be provided through the groove 44b.

If the width of the groove 44b and the slanted angle of the V-shaped outer portion 44a are different, the position contacting with the rod member 30 may changed.

Therefore, a vertical direction load capacity of the bearing may be increased based on the slanted angle with respect to the rod member.

Figure 4 is a perspective view illustrating a linear motion guide 110 according to another embodiment of the present invention. The construction of the linear motion guide 110 is the same as the construction of the linear motion guide 10 of Figure 1, except for the construction that the track rails 120 contact each other. In this construction, a compact sized linear motion guide may be implemented by decreasing the entire size. Namely, the guide of the linear motion guide 110 is the

same as the construction of figure 1, except for the back sides of the track rails 120 contact each other.

Figures 5A and 5B are views illustrating the construction of the track rail 220 according to another embodiment of the present invention. The track rail 220 is extended over the ends of the width direction of the frame member 222. A bolt head potion 224b and a hole 224c are formed in the extended portion 224a for a connection with the base 260. The bolt 238b is engaged through the bolt head portion 224b and the hole 224c for thereby fixing the support member 224 and the base 260. The remaining construction is the same as the construction of the track rail 20 of Figure 1.

Figure 6 is a view illustrating the construction of the track rail 320 according to another embodiment of the present invention. The frame member 322 of the track rail 320 includes a channel 332 for positioning the rod member 330 at both sides. A pair of the rod members 330 are positioned in the channel formed at both sides of the frame member 322 and are engaged using the support member 324 and the bolt 338a for thereby finishing the track rail 320. The construction of the channel formed in the frame member 324 may be the same as the track rail 20 of Figure 1.

The remaining constructions of the same may be the same as the constructions of the track rail 20 of Figure 1.

Figures 7A and 7B are views illustrating the construction of the track rail 420 according to another embodiment of the present invention. A T-shaped groove 436 is formed in a lower portion of the support member 424 of the track rail 420 and is extended in a longitudinal direction. As shown in Figures 7A and 7B, the bolt 438b is inserted thereinto for fixing the base 460 and the track rail 20. The head of the bolt is inserted into the portion 436a having a wider width in a horizontal direction,

and a threaded portion is inserted into the portion having a narrow width. As shown in Figure 7B, the nut 439 is tightened in the lower portion of the base 460 for thereby fixing the track rail 420. The constructions of other elements may be the same as the constructions o the track rail 20 of Figure 1.

In the above described embodiments, the channel is formed in the frame member, and an engaging shoulder portion is formed in order to prevent the rod member from being escaped. In another embodiment of the present invention, a channel (which may be a channel forming a part of the rail groove) or an engaging shoulder portion may be formed in the support member.

The technical concepts of the present invention which may be helpful to understand the above-described embodiments of the present invention will be described. First, the frame member and support member are prepared in two parts for forming the rail groove having an engaging shoulder. The rod member is positioned in the inner side of the engaging shoulder portion before assembling two parts of the frame member or when assembling the same. When engaging two parts of the frame member, the rod member is positioned in the inner side of the engaging shoulder portion of the rail groove. Therefore, when the frame member and the support member are engaged, the rail groove is formed for engaging the rod member thereto. The above construction of the track rail may be understandable by a person skilled in the art.

Figure 8 is a view illustrating the construction according to another embodiment of the present invention. As shown therein, the track rail 520 includes a frame member 522 and a rod member 530. The construction of the frame member 522 is the same as the construction of the frame member of Figure 1. The lower portion of the channel 532 formed in the frame member 522 is covered by the base

560. Therefore, the rail groove 528 to which the rod member 530 is engaged is formed by a part of the upper surface of the base 560 and the channel 532 of the frame member 522. The base 560 which forms a part of the apparatus for engaging a linear motion guide operates as the same element as the support member. In this embodiment of the present invention, the base or the support member may be called as a support in broad meaning.

Figure 9A is a cross sectional view illustrating the construction according to another embodiment of the present invention. As shown in Figure 6, the channel 632 is formed at both sides of the frame member 622 in the same manner as the embodiment of Figure 6. The frame member 622 includes a groove 622a formed in the upper portion of the same and a groove 622b formed in a lower portion of the same. The construction of the channel 632 is the same as the construction of the earlier embodiment of the present invention. The frame member 622 and the rod member 630 are set on the profile base 660. The profile of the profile base 660 may be determined based on the strength, weight, etc. In the present invention, the profile base 660 is not limited to the construction of Figure 9. The profile base 660 includes an upper surface which has a flat portion in part. A part of the upper surface portion 660a forms a rail groove together with the channel 632 of the frame member 622. The profile base 660 and the frame member 622 are engaged in a certain portion using an engaging member such as a bolt, nut, etc.

As shown in Figure 9B, two frame members 622 are arranged in parallel based on the profile base 660a having a large size, and the rod member 630 exposed to both sides is engaged. A linear motion bearing having a large size may be used.

As shown in Figure 9, the profile base which is commercial may be directly

used. In the embodiments of Figure 8 and Figure 9, the rod member is supported in the lower portion for thereby forming a frame member having a channel and a rail groove. A narrower entrance is formed in the axial direction, so that the rod member is not escaped. A certain base may be used for the same purpose.

Figures 10A and 10B are views illustrating the construction according to another embodiment of the present invention. As shown in Figure 10A, the construction is the same the construction of the support member 724. In addition, the frame member 722 is the same the construction of the frame member of Figure 9, except for the support member 724A which is different from the construction of Figure 10A. The support member 724a includes a groove 725 extended in a longitudinal direction. A tooth portion 727 is formed at both lateral walls of the groove 725 for thereby performing a screw function. The tooth portion is extended in the longitudinal direction.

In the above construction, the bolt may be inserted into the base (not shown) and is rotated for thereby being fixed. The tooth portion 727 which operates as a screw of the support member 724a may be fabricated based on an extruding and drawing process.

As described above, in the present invention, when assembling the track rail, the rod member and the frame are not deformed. Therefore, it is possible to fabricate a more precious linear motion guide.

As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.