Patent Application
20090071272
1. Field of the Invention
The present invention relates to a ball screw device, and more particularly to a ball screw device having a molded circulating device for effectively and smoothly receiving and guiding the balls or the rollers or the bearing members to move relative to the ball nut and the screw shaft, and for facilitating the rotational movement of the ball nut and the screw shaft relative to each other in great rotational speeds.
2. Description of the Prior Art
Typical ball screw devices comprise a ball nut rotatably and/or moveably engaged onto a screw shaft, and normally arranged to allow the ball nut to be rotated and/or moved relative to the screw shaft in great rotational speeds. For allowing the ball nut to be smoothly rotated and moved relative to the screw shaft, a suitable bearing device or lubricating structure is further required to be provided and engaged between the ball nut and the screw shaft, for facilitating the rotational movement between the ball nut and the screw shaft.
For example, U.S. Pat. No. 3,971,2648 to Detraz et al. discloses one of the typical screw-and-nut mechanism with ball or roller recirculation including a ball recirculation channel comprising bent, tubular inlet and outlet elements connected to each other by a connecting means, the tubular elements being engaged in a bore of the nut member in such a way as to emerge at the bottom of the thread.
However, the tubular elements are required to be bent from a longitudinal tubular member, and the corner areas or the bent portions of the tubular elements may be distorted such that the balls or the rollers or the bearing members may not suitably move through the tubular elements.
U.S. Pat. No. 4,953,419 to Schlenker, and U.S. Pat. No. 5,063,809 to Schlenker disclose two further typical ball screw and nut assemblies each including a ball return tube having one or more bent portions or elbows for guiding the balls or the rollers or the bearing members.
However, similarly, the return tubes are also required to be bent from a longitudinal tubular member, and the corner areas or the bent portions of the return tubes may be distorted such that the balls or the rollers or the bearing members may not suitably move through the return tubes.
U.S. Pat. No. 5,014,568 to Schlenker discloses a still further typical ball screw and nut assembly including a deflector having a curved and elongate body, and a threaded stem rigidly affixed to the body and integral with the body, and one or more transfer tubes for guiding the balls or the rollers or the bearing members.
However, similarly, the transfer tubes are also required to be bent from a longitudinal tubular member, and the corner areas or the bent portions of the transfer tubes may be distorted such that the balls or the rollers or the bearing members may not suitably move through the transfer tubes.
U.S. Pat. No. 6,023,991 to Tabe et al. discloses a still further typical ball screw device also including one or more circulation tubes for guiding the balls or the rollers or the bearing members.
However, similarly, the circulation tubes are also required to be bent from a longitudinal tubular member, and the corner areas or the bent portions of the circulation tubes may be distorted such that the balls or the rollers or the bearing members may not suitably move through the circulation tubes.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional ball screw devices for such as machine tools or the like.
The primary objective of the present invention is to provide a ball screw device including a molded circulating device for effectively and smoothly receiving and guiding the balls or the bearing members to move relative to the ball nut and the screw shaft, and for facilitating the rotational movement of the ball nut and the screw shaft relative to each other in great rotational speeds.
The other objective of the present invention is to provide a ball screw device including a molded circulating device having a structure for allowing the circulating device to be easily and quickly and precisely formed or made with the molding or mold-injection procedures and to be easily and quickly and readily removed or disengaged from the mold devices.
In accordance with one aspect of the invention, there is provided a ball screw device comprising a screw shaft including an outer thread formed thereon, a ball nut including a bore formed therein for receiving the screw shaft, and including an inner thread formed therein for forming a helical raceway between the ball nut and the screw shaft, the ball nut including two openings formed therein and communicating with the bore of the ball nut, a plurality of bearing members received in the helical raceway between the ball nut and the screw shaft for facilitating a rotating movement between the ball nut and the screw shaft, and a circulating device including a tubular member having two end blocks for engaging into the openings of the ball nut, the tubular member including a passage formed therein and directed toward the inner thread of the ball nut and the outer thread of the screw shaft for receiving the bearing members, the circulating device includes an anti-symmetric structure formed by two identical half members, and each half member is formed by two half segments each having a portion of the passage of the half member for allowing the half segments of the half member to be precisely formed with molding procedures and to be easily and quickly and readily removed or disengaged from the mold devices.
The end blocks of the circulating device each include a compartment formed therein for receiving a lubricating oil therein. The end blocks of the circulating device each include a cap for closing the compartment of the end block and for retaining the lubricating oil in the compartment of the end block.
The end blocks of the circulating device each include a groove formed therein and communicating with the compartment of the block and communicating with the passage of the tubular member for allowing the lubricating oil in the compartment of the block to flow into the passage of the tubular member and then to flow into the inner thread of the ball nut and the outer thread of the screw shaft.
The end blocks of the circulating device each include an oil retaining member engaged into the groove of each of the end blocks of the circulating device.
The end blocks of the circulating device each include a deflecting tongue provided therein for forming a portion of the passage of the tubular member and for directing the passage of the tubular member toward the inner thread of the ball nut and the outer thread of the screw shaft.
The circulating device includes at least one ear extended from the tubular member and having an orifice formed therein for engaging with a fastener which detachably secure the circulating device to the ball nut. The two half members each include one half of the ear provided thereon.
Further objectives and advantages of the present invention will become apparent from a careful reading of the detailed description provided hereinbelow, with appropriate reference to the accompanying drawings.
Referring to the drawings, and initially to
A multiple turn, helical raceway 22 will be formed between the ball nut 10 and the screw shaft 20 for rotatably and/or movably receiving one or more groups of balls or rollers or rolling or ball bearing members 80 (
The ball nut 10 includes a cut off portion or a recess 14 formed in the outer peripheral portion thereof, and formed or defined by a flat surface 15, and includes two openings 16, 17 formed therein and communicating with the bore 11 of the ball nut 10 (
The circulating device 30 includes a bent or curved or tubular member 31, one or more (such as two) ears 32 extended from the tubular member 31 and each having an orifice 33 formed therein for engaging with the fasteners 19 (
As shown in FIGS. 2 and 5-6, the tubular member 31 includes a passage 36 formed therein and directed toward the inner thread 12 of the ball nut 10 and the outer thread 21 of the screw shaft 20 for rotatably and/or movably receiving one or more groups of balls or rollers or rolling or ball bearing members 80 therein and for allowing the ball bearing members 80 to form an endless ball train. The blocks 34 each include a pathway or compartment 37 formed therein (
As shown in
The two half members 40 each may include one half of the tubular member 31 and one half of the ears 32 and one of the blocks 34, and each may further be made or formed by two half segments 50, 51 (
As shown in
Accordingly, the ball screw device in accordance with the present invention includes a radially inserted circulating device for separating and for effectively and smoothly receiving and guiding the balls or bearing members to move relative to the ball nut and the screw shaft, and having a structure for allowing the circulating device to be easily and quickly and precisely formed or made with the molding or mold-injection procedures or methods and to be easily and quickly and readily removed or disengaged from the mold devices.
Although this invention has been described with a certain degree of particularity, it is to be understood that the present disclosure has been made by way of example only and that numerous changes in the detailed construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.
