Oil storing ball recirculation block of leadscrew

Disclosed herein is a leadscrew ball recirculation block with oil storing means wherein an cavity in the ball recirculation block which being not effectively used for circulating balls is utilized for storing lubrication oil. An oil exuding hole is provided to communicate with the oil stored cavity and a turning passage for balls so as to lubricate the moving balls. In order to prevent the lubrication oil remained at a standstill in a certain region in the cavity by its own gravity from failing to lubricate the balls, there is provided an oil containing element with a plurality of oil absorbing and distribution branches to lubricate the balls just passing by the turning passage. Furthermore, the ball recirculation block is formed of two pieces of plastic members bonded by supersonic wave bonding technique so as to achieve reduction of manufacturing cost and ensure perfect oil sealing effect of the ball recirculation block. With the result of such a construction, the usable lifetime of the ball recirculation block is prolonged and repeated replenishing of new oil is evaded. (FIG. 2)

BACKGROUND OF THE INVENTION
 1. Field of the invention
 The present invention relates to a ball recirculation block of leadscrew,
 and more particularly, to a leadscrew ball recirculation block having oil
 storing means.
 2. Brief description of the prior art
 A leadscrew assembly is conventionally constituted of a screw shaft, and a
 ball nut unit combined thereof together with a plurality of balls
 recirculating therebetween, wherein the outer surface of the screw shaft
 is formed into a spiral groove having semi-circular-liked cross section.
 The ball nut unit further includes a nut body and other components which
 carry balls to recirculate. The nut body is hollow with its inner surface
 formed into a spiral groove of semi-circular-liked cross section
 corresponding to the spiral groove formed on the outer surface of the
 screw shaft thereof. By recirculation of the balls, screw shaft and the
 nut unit are able to rotate relatively.
 Usually, the ball recirculation block for a conventional leadscrew assembly
 has no oil storing means because it is believed that too big investment is
 required to add extra oil storing means to a leadscrew assembly.
 SUMMARY OF THE INVENTION
 The present invention has thus been made in view of such conventional
 problem. Accordingly, it is an object of the present invention to provide
 oil storing means in unutilized space of leadscrew ball recirculation
 block.
 It is another object of the present invention to provide oil storing means
 for a leadscrew assembly without aggravatively increasing the
 manufacturing cost.
 It is still another object of the present invention to provide oil storing
 means for a leadscrew assembly with improved oil storing effect to prolong
 the usable duration of oil stored in the leadscrew assembly without
 replenishing new oil repeatedly at short intervals.
 To achieve the objects mentioned above, in the oil storing ball
 recirculation block of the present invention, an cavity in the ball
 recirculation block which being not used effectively is utilized for
 storing oil, an oil exuding hole is provided to communicate with the oil
 stored cavity and a turning passage for balls so as to lubricate the
 moving balls. In order to prevent the oil remained at a standstill in a
 certain region of the cavity by its own gravity from failing to lubricate
 the balls, the present invention provides an oil containing element with a
 plurality of oil absorbing and distributing branches to absorb oil
 remained anywhere and transport oil to lubricate the balls just passing
 along the turning passage. Furthermore, the ball recirculation block is
 formed of two pieces of plastic members bonded by supersonic wave bonding
 technique so as to achieve reduction of manufacturing cost and ensure
 perfect oil sealing effect of the ball recirculation block. With the
 result of such a construction, the usable lifetime of the ball leadscrew
 is prolonged and repeated replenishing of new oil is evaded. Incidentally,
 blanket, flannel and cotton cloth thread can be used to form the oil
 containing element.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
 Hereinafter, the bast mode for carrying out the present invention will be
 described more fully below with reference to attached drawings:
 Referring to FIG. 1 through FIG. 3, wherein FIG. 1 is a three dimensional
 view showing an example of assembled leadscrew and its ball recirculation
 block of the present invention, FIG. 2 is a three dimensional view of a
 leadscrew ball recirculation block of the present invention, and FIG. 3 is
 a cross sectional view of FIG. 1 As shown in these drawings, the leadscrew
 consists of a screw shaft A with a nut body B combined threrearound, the
 leadscrew ball recirculation blocks of the present invention are attached
 to both ends of nut body B. The ball recirculation block is constituted by
 a base 1 and a cover 2 of the ball recirculation block. The cover 2 and
 the base 1 are engaged together up and down with an oil containing element
 3 accommodated therein. The base 1 are provided with several fixing bolt
 holes 13 for engaging the ball recirculation block to the nut body B.
 Further, there are formed several sinks 131 for fixing bolt on the base 1,
 and corresponding breaches 21 for fixing bolt hole formed on the cover 2
 so as to bury the heads of the fixing bolts into the ball recirculation
 block thereby minimizing the occupied space. An oil nipple thread hole 24
 is formed on the cover 2 for connecting an oil nipple to replenish new
 oil. Several ball guide members 14 are provided in the base 1. The lower
 end of the ball guide member 14 is formed into a guide lip 141 for guiding
 the ball moving around the spiral groove of the nut body into a turning
 passage 17, while the upper end of the ball guide member 14 is formed into
 a scraper lip 142 to clean up dregs accumulating in the spiral groove
 formed on the screw shaft of the leadscrew.
 FIGS. 4 and 5 are three dimensional drawings of the cover of the leadscrew
 ball recirculation block of the present invention. As shown in FIGS. 5,
 several positioning studs 22 stand on the cover 2 for exactly positioning
 the relative position when the cover 2 is fitted on the base 1. A guide
 surface 221 are formed on the side wall of the positioning stud 22 for
 guiding an oil distribution branch 33 of the oil containing element 3 to
 an accurate position. In order to facilitate and ensure hermetical effect
 of the supersonic wave bonding to be performed to mutually bond the cover
 2 and the base 1, a flange 23 is formed along the edge of the cover 2.
 FIG. 6 is a three dimensional view of the base of the leadscrew ball
 recirculation block of the present invention. As shown in FIG. 6, an
 cavity 18 is formed in a vertical direction above the bottom plate 10 of
 base 1, and in a horizontal direction between outer rim 11 and inner rim
 12 of the base 1, this cavity 18 is utilized to store the lubrication oil.
 An enhancing stand 15 is formed in the vicinity of each ball turning
 passage 17 for intensifying the turning passage 17. A hole 16 for
 positioning stud 22 is also bored in the vicinity of the turning passage
 17 for accepting the positioning stud 22 to fit the cover 2 and base 1 at
 a right position before they are to be bonded each other by the supersonic
 wave bonding.
 FIG. 7 is a three dimensional drawing of the base described in FIG. 6 being
 viewed from an inverse direction. In order to align the ball turning
 passage 17 accurately with respect to the ball recirculation hole of the
 nut body B, when the base 1 of the ball recirculation block is engaged to
 the nut body B, a guiding lip 171 is formed at the terminal of the turning
 passage 17. Besides, in order to enhance stability of engagement between
 the base 1 and the nut body B, a positioning ring 111 is provide around
 the circumference of the base 1 which is used to fit along the outer
 diameter of the nut body B.
 FIG. 8 is a fractional cross section view in the vicinity of two oil
 distribution branch guide slots 162, 163 formed on the base of the
 leadscrew ball recirculation block of the present invention. As shown in
 FIG. 8, oil distribution branch guide slots 162, 163 are formed at each
 side of the positioning hole 16 respectively. The guide slot 162 crosses
 through the turning passage 17, and an oil exuding hole 161 which being
 able to draw the lubrication oil from the oil storing cavity 18 and
 instill it into the turning passage 17 is thereby formed between the
 turning passage 17 and the positioning hole 16.
 FIG. 9 is a fractional cross section view in the vicinity of the oil
 distribution branch guide slots (162, 163) after three components of base
 1, cover 2, and oil containing element 3 of the leadscrew ball
 recirculation block are assembled. As shown in FIG. 9, when the three
 above mentioned components have been assembled in the position thereof,
 the oil distribution branch 33 is guided to its right position and in
 addition, is squeezed by the positioning stud 22 thereby alleviating the
 oozing rate of oil out of the oil distribution branch 33. The oil
 distribution branch 33 is slightly protruding out of the exit of the oil
 exuding hole 161 so as to directly contact and lubricate the balls passing
 by the turning passage 17.
 FIG. 10 is a contour drawing of the pre-assembling oil containing element 3
 in the leadscrew ball recirculation block of the present invention. As
 shown in FIG. 10, the oil containing element 3 includes an oil absorbing
 ring 31, several oil absorbing branches 32 and corresponding amount of oil
 distribution branches 33. As the leadscrew assembly is set at random
 without in a specified direction when in operation, the lubrication oil
 stored in the cavity 18 is likely to remain at a standstill in a certain
 region in the cavity 18 by its own gravity and fail to lubricate the
 balls. To eliminate the shortcoming like this, in the present invention
 the oil absorbing branches 32 are disposed radially and in connection with
 the oil absorbing ring 31 and the oil distribution branches 33 so that
 each individual oil distribution branch 33 located at any position is able
 to keep oil thereof and lubricate the balls passing by the adjacent
 turning passage 17.
 FIG. 11 is a contour drawing of the assembled oil containing element 3, and
 FIG. 12 is a three dimensional view of the leadscrew ball recirculation
 block of the present invention wherein the cover 2 and the base 1 are
 fitted together with the assembled oil containing element 3 installed
 therein. As shown in FIGS. 11 and 12, the oil absorbing branches 32 are
 disposed radially, while the oil distribution branches 33 enter the oil
 exuding holes 161 via their respective oil distribution guide slots 162 to
 lubricate the balls passing by the adjacent turning passages 17.
 Incidentally, blanket, flannel and cotton cloth threadcan be used to form
 the oil containing element 3.
 Many changes and modifications in the above described embodiment of the
 invention can, of course be carried out without departing from the scope
 thereof. Accordingly, to promote the progress in science and the useful
 arts, the invention is disclosed and is intended to be limited only by the
 scope of the appended claims.