Bearings – Linear bearing – Recirculating
Reexamination Certificate
2001-07-18
2003-02-25
Footland, Lenard A. (Department: 3682)
Bearings
Linear bearing
Recirculating
C384S013000
Reexamination Certificate
active
06524003
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a linear motion guiding apparatus in which a passage forming member formed of resin is built into a body of movable member.
2. Description of the Related Art
The applicant has already proposed a technical idea that, in a movable block of a linear motion guiding apparatus, a pair of ball passage forming portions extending along the opposite longitudinal sides of a loaded-ball running groove, a ball returning passage forming portion and a pair of direction changing passage-inner guide forming portions were integrally formed of resin with a body of the movable block (refer to Japanese Patent Provisional Publication No. H7-317,762).
More specifically, when a resin forming is carried out, the body of the movable block is inserted in a die, and the ball passage forming portions, the direction changing passage-inner guide forming portions or the ball returning passage forming portion is integrally formed with the block body.
In the conventional movable block obtained by the integral forming, the block body is inserted in the die, as mentioned above. When the block body has a large size, a large-scaled die is required to be used. It is not easy to prepare such a large-scaled die, and there is actual restriction in size. The ball passage forming portions located at the opposite longitudinal sides of the ball running groove extending along the longitudinal direction of the block body are thin and long, with the result that molten resin may not reach every part of the space for forming the ball passage forming portions during the resin forming treatment.
Increase in number of gates formed on the die may solve the above-mentioned problem of misrun of the molten resin. However, when the block body is inserted in the die, the block body may deteriorate the run of the molten resin.
When the movable block has a pair of wing portions, which face right and left-hand side portions of the guide rail so that the guide rail is held between the wing portions, and there are four trains of balls between the right and left-hand side portions of the guide rail and the right and left-hand wing portions of the moving block, and more specifically, the upper and lower trains of balls are arranged at each of a gap between the right-hand side portion of the guide rail and the corresponding right-hand wing portion of the moving block and another gap between the left-hand side portion of the guide rail and the corresponding left-hand wing portion of the moving block, the block body inserted in the die may deteriorate the run of the molten resin in the width direction of the moving block.
SUMMARY OF THE INVENTION
An object of the present invention is therefore to provide a linear motion guiding apparatus in which a resin-formed body for forming a rolling member circulation passage is formed separately from a body of a movable member so as to permit easy formation of the resin-formed body, and such a resin-formed body is able to be built in the body of the movable member, ensuring integral formability of the maximum number of unit parts for defining the rolling member circulation passage.
In order to attain the aforementioned object, a linear motion guiding apparatus comprises:
a guide member provided with a rolling member running track, and
a movable member arranged so as to be movable along the guide member through a large number of rolling members, said movable member being provided with (i) a rolling member running counter-track corresponding to the rolling member running track of said guide member, (ii) a rolling member returning passage arranged away from said rolling member running counter-track by a prescribed distance and in parallel therewith and (iii) a pair of direction changing passages for connecting the rolling member running counter-track and the rolling member returning passage to permit circulation of the rolling members,
characterized in that:
a resin-formed body for forming a rolling member circulation passage comprises a pair of rolling member passage forming portions extending along both longitudinal sides of said rolling member running counter-track, a returning passage forming portion for forming the rolling member returning passage and a pair of direction changing passage-inner guide forming portions for forming inner peripheral guide portions of said direction changing passages, said resin-formed body being separately formed from a body of said movable member; and
at least two portions of (a) said pair of rolling member passage forming portions, (b) said returning passage forming portion, (c) one of said pair of direction changing passage-inner guide forming portions and (d) another of said pair of direction changing passage-inner guide forming portions are connected with each other through integral forming so that said resin-formed body can be built in the body of said movable member.
Embodiments of the combination of these portions (a) to (d) for the resin-formed body for forming the rolling member circulation passage may include the following three examples:
the first example in which the resin-formed body comprises (i) an integral body of the pair of rolling member passage forming portions and the pair of direction changing passage-inner guide forming portions, and (ii) the returning passage forming portion separately formed from the integral body
the second example in which the resin-formed body comprises (i) an integral body of the pair of rolling member passage forming portions, the returning passage forming portion and one of the pair of direction changing passage-inner guide forming portions, and (ii) another of the pair of direction changing passage-inner guide forming portions separately formed from the integral body; and
the third example in which the resin-formed body is manufactured by preparing an integral body of the pair of rolling member passage forming portions, the returning passage forming portion and the pair of direction changing passage-inner guide forming portions, and then dividing the pair of rolling member passage forming portions and the returning passage forming portion in longitudinal intermediate portions thereof into respective two parts.
According to the present invention, the resin-formed body for forming the rolling member circulation passage is separately formed from the body of the movable member. Even if the movable member has a large size, the flow of molten resin is not therefore restricted by the body of the movable member unlike the conventional prior art in which the body of the movable member and the resin-formed body are integrally formed with each other, and it is possible to ensure proper run of molten resin through increase in a number of gates in the die, thus leading to an excellent formability. In general, it is hard to achieve proper run of molten resin especially at the rolling member passage forming portions extending along the longitudinal sides of the rolling member running counter-track, and it is therefore effective to separately form the resin-formed body from the body of the movable member in the same manner as the present invention.
The rolling member circulation passage is formed by the resin-formed body. Therefore, the direct positioning can be achieved in the relative positional relationship between the direction changing passage-inner guide forming portions and the rolling member passage forming portion, as well as the relative positional relationship between the direction changing passage-inner guide forming portions and the returning passage forming portion, and the continuity of the rolling member circulation passage is properly ensured, thus leading to smooth run of the rolling members.
Since the rolling member passage forming portions are located along the both longitudinal sides of the rolling member running counter-track, the direction changing passage-inner guide forming portions having a proper relative positional relationship with the rolling member passage forming portions are accurately set on the both ends of the rolling me
Hirokawa Tadashi
Iida Katsuya
Michioka Hidekazu
Mochizuki Hiroaki
Yoshihashi Masahiro
Footland Lenard A.
THK Co. Ltd.
Young & Thompson
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