Lubrication – Slide-bearing lubrication
Reexamination Certificate
1999-04-09
2002-06-11
Bucci, David A. (Department: 3682)
Lubrication
Slide-bearing lubrication
C384S013000, C184S100000
Reexamination Certificate
active
06401867
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a lubricant supplying unit for coating the surface of the track shaft with lubricant in a linear motion apparatus, for example, a linear guide unit and ball screw, in which a track shaft engages a slide member such that they are movable relative to each other through rolling bodies such as balls and rollers, and more specifically, to a linear motion apparatus using the same.
2. Description of the Related Art
Conventionally, this kind of the linear motion apparatus has been used in a linear guide section of a machine tool, transfer unit and the like, and includes a linear guide unit which is mounted on a fixing unit such as a bed and a saddle for guiding a movable unit such as a table and a ball screw which is used together with this linear motion unit for providing the above mentioned movable unit with the linear motion stroke depending on a rotation speed of a motor.
The former linear guide unit comprises a track rail (track shaft) which is disposed on the aforementioned fixing unit and in which rolling grooves for balls are formed in the length direction thereof, and a sliding base (sliding member) which has a load rolling groove opposing the rolling groove in the track rail through a plurality of balls and in which an infinite circulation path for the balls rolling in the load rolling groove is formed. This linear guide unit is so constructed that the sliding base supporting the aforementioned movable body carries out linear motion continuously along the track rail with an infinite circulation of the balls. On the contrary, in some cases, the track rail is so constructed to move relative to the fixed sliding base.
On the other hand, the latter ball screw comprises a screw shaft (track shaft) in which a spiral ball rolling groove is formed at a predetermined lead and a nut member (slide member) which has a load rolling groove opposing the ball rolling groove through a plurality of balls and in which an infinite circulation path for the balls rolling in this load rolling groove is formed. This ball screw is so constructed that the balls circulate in the aforementioned infinite circulation path with a relative rotation between the screw shaft and nut member and the nut member and screw shaft move relative to each other in the axial direction.
Upon use of these linear motion apparatuses, the balls, rolling grooves and the like need to be appropriately lubricated depending on a use condition in order to suppress wear of the balls themselves, rolling grooves of a track rail or screw shaft in which the balls roll and load rolling groove of a sliding base or nut member, and further maintain a high precision motion of the slide member for a long time.
Unexamined Published Japanese Patent Application No. 307442/1994 has disclosed a lubricant supplying system for supplying lubricant to balls, rolling grooves and the like. As shown in
FIG. 22
, in this lubricant supplying system, a pad
127
soaked in lubricant is accommodated within a cover frame
128
and the cover frame
128
is engaged with a track rail
129
so that the pad
127
inside comes into contact with the track rail
129
. The cover frame
128
is mounted backward and forward with respect to the traveling direction of the cover frame
128
such that as the sliding base
130
moves, the aforementioned pad
127
comes into contact with the track rail
129
. Therefore, if the sliding base
130
moves back and forth along the track rail
129
, lubricant leaking from the aforementioned pad
127
is coated on the surface of the track rail
129
so that lubricant is supplied to the rolling grooves and balls.
However, because in the conventional lubricant supplying system, lubricant is applied to all the rolling grooves for balls provided in the track rail with a substantially single pad, there is a problem that lubricant cannot be applied equally to all the rolling grooves depending on a mounting posture of the track rail relative to the fixing unit such as a bed.
That is, lubricant is likely to flow vertically downward within the pad by its own gravity, for example, as shown in FIG.
23
, if the track rail is mounted on the fixing portion
130
in a laterally fallen condition more lubricant is contained in the lower half portion of the pad. Therefore, although a sufficient amount of lubricant can be applied to the side face of the track rail positioned down, the sufficient amount of lubricant cannot be applied to the side face of the track rail positioned up, so that lubricant cannot be applied equally to all the rolling grooves.
OBJECT AND SUMMARY OF THE INVENTION
Accordingly, the present invention has been made in viewpoints of these problems, and it is an object of the invention to provide a lubricant supplying unit preferable for a linear motion apparatus such as a linear guide unit, a ball screw unit and the like, always capable of coating all rolling body rolling grooves formed on a track shaft with an equal amount of lubricant regardless of a difference in the mounting posture of the track shaft with respect to a fixing unit, and more to provide a linear motion apparatus using the same.
That is, to achieve the above object, the present invention provides a lubricant supplying system mounted on a slide member engaging a track shaft through rolling bodies for applying lubricant to the track shaft with a relative motion between the slide member and track shaft, the lubricant supplying system comprising: a casing fixed to the slide member; a plurality of coating pieces which are protruded from plural positions of the casing so that they are in contact with the track shaft for coating the track shaft with lubricant; and lubricant accommodating chambers provided in the casing for supplying lubricant to the coating piece, wherein the plurality of the coating pieces are divided into groups comprising one or two or more adjacent coating pieces, and each group has a lubricant accommodating chambers.
The linear motion apparatus of the present invention comprises a track shaft in which rolling faces for rolling bodies are formed, a sliding member which engages the track shaft through the rolling bodies and slides relative to said track shaft, and a lubricant supplying member which is mounted on the sliding member for coating the surface of the track shaft with lubricant with such a relative motion, wherein the lubricant supplying member comprising a casing fixed to the sliding member, coating pieces which are protruded from plural positions of this casing such that they are in contact with the track shaft for coating the track shaft with lubricant, and lubricant accommodating chambers provided in the casing for supplying lubricant to the coating pieces, the plurality of the coating pieces being divided to groups consisting of one or two or more adjacent coating pieces while lubricant accommodating chamber formed dividedly for each group.
According to such a technological method, the plurality of the coating pieces for coating the track shaft with lubricant are protruded from the plural positions of the casing such that they are in contact with the track shaft and lubricant is supplied from the lubricant accommodating chamber in the casing to the coating pieces. As a result, if the sliding member moves relative to the track shaft, lubricant is coated to the surface of the track shaft by each coating piece.
According to the present invention, as the plurality of the coating pieces are divided to groups consisting of one or two or more adjacent coating pieces and the lubricant accommodating chamber is formed dividedly for each group, lubricant is only allowed to flow in the lubricant accommodating chamber of each group, thus it will not be concentrated on a particular position in the casing.
Thus, the amount of lubricant to be supplied to each coating piece can be substantially equalized, so that it is possible to coat the track shaft with constantly equal amount of lubricant unconcentratedly from these coating pieces.
Further, because in such linear moti
Honma Mitsuaki
Michioka Hidekazu
Arent Fox Kintner & Plotkin & Kahn, PLLC
Bucci David A.
Kim Chong H.
THK Co. Ltd.
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