JP6649993B2 - External circulation ball screw - Google Patents

Description

  The present invention relates to a ball screw, particularly to an external circulation type ball screw.

  General ball screws are classified into internal circulation type and external circulation type. When the load is large, an external circulation type ball screw is often used. The external circulation type ball screw disclosed in Patent Literature 1 smoothly maintains the operation of the ball screw by connecting the return paths of the two return members disposed in the concave grooves to circulate the balls.

  However, the above-mentioned external circulation type ball screw has the following two problems.

  1. In order to connect the return path of the return member in the nut, it is necessary to design return members having different dimensions in accordance with nuts having different lengths (the number of threads), thereby increasing production costs. .

  2. Since the reflux member is manufactured by injection molding, deformation tends to occur as the length increases. When performing the assembling work, if the time required for adjusting the reflux member increases, the time required for the assembling work increases. If the recirculation member deforms, the recirculation path of the recirculation member cannot be accurately connected, and the ball cannot circulate smoothly.

Taiwan Patent No. I509169

  SUMMARY OF THE INVENTION It is a main object of the present invention to provide an external circulation type ball screw in which nuts having different lengths have the same size as a recirculating member, and the manufacturing cost of a mold can be reduced.

  An external circulation type ball screw for solving the above-mentioned problem includes a screw shaft, a nut, a lid, two reflux members, and a plurality of rolling members. The screw shaft has a thread groove on the outside. The nut is mounted on the screw shaft so as to be movable in the axial direction of the screw shaft, and has a thread groove inside. The thread groove of the nut and the thread groove of the screw shaft constitute a load path. The nut further has a concave groove on the surface, two return holes and a first level formed in the concave groove, and a first half return path formed on the first level. The two return holes communicate the load path and the concave groove. The first level is located between the two reflux holes. The lid is arranged on the nut so as to cover the concave groove of the nut, and has a second half and a second half return path formed in the second hierarchy inside. The second half return path and the first half return path constitute a return path. The two return members have a passage formed therein, with one end of the passage being a first end and the other end of the passage being a second end. Each of the two return members has a first end inserted into the return hole of the nut to connect the passage and the load path, and a second end located on both sides of the return passage. The passages of the two reflux members are respectively connected to the reflux passages. The load path, the return path and the two paths constitute a return path. The plurality of rolling members are arranged so as to be movable in the return path.

As described above, the external circulation type ball screw according to the present invention combines a return member having the same size with a return member having a different length by the first half return path formed on the nut and the second half return path formed on the lid. Therefore, not only can nuts having different lengths be accommodated, but also the manufacturing cost of the mold for the reflux member can be reduced.
In addition, by arranging the return path, the length required for the return member can be reduced, deformation of the return member in the manufacturing operation can be suppressed, and the efficiency of the ball screw assembly operation can be improved.

  If relatively preferred, the second ends of the two return members abut the first or second level. If the two recirculation members are brought into contact with the first or second level, the stability of the arrangement of the recirculation members on the nut can be increased.

  Each of the two reflux members has a convex fixing portion formed at the second end. The lid has an abutment wall formed on opposite sides of the second level, and a fixing groove formed between the abutment wall and the second level. The convex fixing portion is limited within the fixing groove. As described above, the two return members can be mounted and stabilized in the nut.

  The lid further has a lubrication hole. The lubrication hole is connected to the return path. Lubricating oil is injected into the inside of the lid from the lubrication hole, and can directly moisten the plurality of rolling members.

  In order to solve the above-mentioned problem, the external circulation type ball screw includes a screw shaft, a nut, a lid, two return members, and a plurality of rolling members. The screw shaft has a thread groove on the outside. The nut is mounted on the screw shaft so as to be movable in the axial direction of the screw shaft, and has a thread groove inside. The thread groove of the nut and the thread groove of the screw shaft constitute a load path. The nut further has a concave groove on the surface and two return holes formed in the concave groove. The two return holes communicate the load path and the concave groove. The lid is disposed on the nut so as to cover the concave groove of the nut. The external circulation ball screw further has a third level formed inside the lid or in the concave groove of the nut, and a return path formed in the third level. The third level is located between the two return holes of the nut. The two return members have a passage formed therein, with one end of the passage being the first end and the other end of the passage being the second end. Each of the two return members has a first end inserted into the return hole of the nut to connect the passage and the load path, and has second ends located on both sides of the return passage. The passages of the two reflux members are respectively connected to the reflux passages. The load path, the return path and the two paths constitute a return path. The plurality of rolling members are arranged so as to be movable in the return path.

  If relatively preferred, the second ends of the two return members abut the third level. If the two return members abut on the third level, the stability of the arrangement of the return members on the nut can be increased.

  Each of the two reflux members has a convex fixing portion formed at the second end. The lid has an abutment wall formed on opposite sides of the third level and a fixing groove formed between the abutment wall and the third level. The convex fixing portion is limited within the fixing groove. As described above, the two return members can be mounted and stabilized in the nut.

  The lid further has a lubrication hole. The lubrication hole is connected to the return path. Lubricating oil is injected into the inside of the lid from the lubrication hole, and can directly moisten the plurality of rolling members.

It is a perspective view showing an external circulation type ball screw by a 1st embodiment of the present invention. It is an exploded perspective view showing a part of external circulation type ball screw by a 1st embodiment of the present invention. 1 is an exploded perspective view illustrating an external circulation type ball screw according to a first embodiment of the present invention. FIG. 4 is a sectional view taken along line 4-4 in FIG. 1. FIG. 5 is a sectional view taken along line 5-5 in FIG. 1. FIG. 9 is an exploded perspective view showing a state where a third layer is formed in a concave groove of a nut in an external circulation type ball screw according to a second embodiment of the present invention. It is an exploded perspective view showing the state where the third rank was formed inside the lid in the external circulation type ball screw according to the second embodiment of the present invention.

  Hereinafter, an external circulation type ball screw according to the present invention will be described with reference to the drawings.

(1st Embodiment)
As shown in FIGS. 1 to 5, the external circulation type ball screw 10 according to the first embodiment of the present invention includes a screw shaft 11, a nut 12, a lid 13, two recirculation members 14, and a plurality of rolling members 15.

  The screw shaft 11 has a screw groove 111 on the outside.

The nut 12 is mounted on the screw shaft 11 so as to be movable in the axial direction of the screw shaft 11, and has a screw groove 121 inside. The screw groove 121 of the nut 12 and the screw groove 111 of the screw shaft 11 constitute a load path P1.
The nut 12 further has a concave groove 122 on its surface, two return holes 123 and a first level 124 formed in the concave groove 122, and a first half return path 125 formed on the first level 124. The two return holes 123 communicate the load path P <b> 1 with the concave groove 122. The first level 124 is located between the two return holes 123.

  The lid 13 is disposed on the nut 12 so as to cover the concave groove 122 of the nut 12, and has a second level 131 and a second half return path 132 formed in the second level 131 inside. The second half return path 132 and the first half return path 125 constitute a return path P2.

The two recirculation members 14 have a passage 141 formed therein. One end of the passage 141 becomes a first end 142, and the other end of the passage 141 becomes a second end 143. The two return members 14 each have a first end 142 inserted into the return hole 123 of the nut 12 to connect the passage 141 with the load path P1, and have second ends 143 located on both sides of the return path P2.
The passages 141 of the two reflux members 14 are respectively connected to the reflux passages P2. The load path P1, the return path P2, and the two paths 141 constitute a return path P3.

  The plurality of rolling members 15 are arranged so as to be able to move into the return path P3.

Due to the above-mentioned structural features, the external circulation type ball screw 10 according to the present invention can use the recirculating member 14 having the same size even if the nut 12 has a different length. In addition, the effect of circulating the rolling member 15 can be obtained by combining the recirculating member 14 having the same size with the recirculating path P2 having a different length.
Further, if there is only a mold of the reflux member 14 having the same size, it is not necessary to separately take a mold having a different size, so that the cost of manufacturing the mold can be reduced. Furthermore, by arranging the return path P2, the length of the return member 14 can be reduced, deformation of the return member 14 during manufacturing operation can be suppressed, and the efficiency of the ball screw assembly operation can be improved.

  In the present embodiment, since the second ends 143 of the two return members 14 abut on the first layer 124 or the second layer 131, the stability of the arrangement of the return members 14 on the nut 12 can be increased. Each of the two reflux members 14 has a convex fixing portion 144 formed at the second end 143. The lid 13 has a contact wall 133 formed on both sides of the second layer 131 opposite to each other, and a fixing groove 134 formed between the contact wall 133 and the second layer 131. The convex fixing portion 144 is limited in the fixing groove 134. As described above, the two return members 14 are mounted in the nut 12 and can be stabilized.

The above is a description of the technical features of the present embodiment. However, the present embodiment is not limited to the above, that is, the same size of the recirculating member 14 is used for the nuts 12 having different lengths without employing the above-described technology. In addition, the manufacturing cost of the mold can be reduced.
For example, the second end 143 of each reflux member 14 may be brought into contact with the first level 124 or the second level 131, a fixing groove 134 and a convex fixing portion 144 may be disposed, or the second end 143 may be connected to the first level. A method may be adopted in which the level 124 or the first level 131 is separated, or a method in which the fixing groove 134 and the convex fixing portion 144 are not disposed. That is, if the rolling member 15 is prevented from deviating from the recirculating path P3 between the passage 141 and the recirculating path P2, the circulation of the rolling member 15 can be maintained.

  In the present embodiment, the lid 13 further has an oil hole 135. The lubrication hole 135 is connected to the return path P2. The lubricating oil is injected into the inside of the lid 13 from the lubrication hole 135 and can directly wet the plurality of rolling members 15.

(2nd Embodiment)
FIGS. 6 and 7 show an external circulation type ball screw 10 according to a second embodiment of the present invention.
The difference from the first embodiment is that the third level 161 is formed inside the lid 13 or in the concave groove 122 of the nut 12, and the third level 161 is located between the two return holes 123. To form a return path P2.

In the present embodiment, since the second ends 143 of the two recirculation members 14 abut on the third story 161, the stability of the arrangement of the recirculation members 14 on the nut 12 can be increased. Each of the two reflux members 14 has a convex fixing portion 144 formed at the second end 143.
The lid 13 has contact walls 133 formed on opposite sides of the third story 161, and a fixing groove 134 formed between the contact wall 133 and the third story 161. The convex fixing portion 144 is limited in the fixing groove 134. As described above, the two return members 14 are mounted in the nut 12 and can be stabilized.

  The above is the description of the technical features of the present embodiment. However, the present embodiment is not limited to the above description. That is, even if the above-described technique is not used, the same size of the recirculating member 14 is used for the nuts 12 having different lengths. Therefore, the manufacturing cost of the mold can be reduced.

  In the present embodiment, the lid 13 further has an oil hole 135. The lubrication hole 135 is connected to the return path P2. The lubricating oil is injected into the inside of the lid 13 from the lubrication hole 135, and can directly moisten the plurality of rolling members 15.

Reference Signs List 10 external circulation ball screw 11 screw shaft 111 screw groove 12 nut 121 screw groove 122 concave groove 123 return hole 124 first level 125 first half return path 13 lid 131 second level 132 second half return path 133 contact wall 134 Fixed groove 135 Lubrication hole 14 Reflux member 141 Passage 142 First end 143 Second end 144 Convex fixing portion 15 Rolling member 161 Third level P1 Load path P2 Reflux path P3 Reflux path

Claims (3)

With a screw shaft, nut, lid, two independent reflux members and a plurality of rolling members,
The screw shaft has a screw groove on the outside,
The nut is mounted on the screw shaft so as to be able to move along the axial direction of the screw shaft, and has a screw groove inside, and the screw groove of the nut and the screw groove of the screw shaft serve as a load path. Make up,
The nut further has a concave groove on the surface, two return holes and a first level formed in the concave groove, and a first half return path formed on the first level. A return hole communicates the load path with the concave groove, the first level is located between the two return holes,
The lid is disposed on the nut so as to cover the concave groove of the nut, and has a second half return path formed on a second level and the second level on the inside, and the second half return path. The first half return path constitutes a return path,
The two return members have a passage formed therein, one end of the passage is a first end, the other end of the passage is a second end, and the first end is the return of the nut. The passage is connected to the load path by being inserted into a hole, the second end is located on both sides of the return path, the path is connected to the return path, the load path, the return path and the path are Constitute a return path,
The plurality of rolling members are arranged so as to be able to move into the return path ,
The reflux member has a convex fixing portion formed at the second end,
The lid has contact walls formed on opposite sides of the second story, and a fixing groove formed between the contact wall and the second story,
The return member is characterized Rukoto convex fixing part is positioned fitted into the fixing groove of the lid,
External circulation ball screw.   The external circulation type ball screw according to claim 1, wherein the lid further has an oil hole, and the oil hole is connected to the return path. With a screw shaft, nut, lid, two independent reflux members and a plurality of rolling members,
The screw shaft has a screw groove on the outside,
The nut is mounted on the screw shaft so as to be able to move along the axial direction of the screw shaft, and has a screw groove inside, and the screw groove of the nut and the screw groove of the screw shaft serve as a load path. Make up,
The nut further has a concave groove on its surface and two return holes formed in the concave groove, and the two return holes communicate the load path and the concave groove,
The lid is disposed on the nut so as to cover the concave groove of the nut,
Inside the lid or in the concave groove of the nut, a third level and a return path formed in the third level, wherein the third level is between the two return holes of the nut. Located in
The two return members have a passage formed therein, one end of the passage is a first end, the other end of the passage is a second end, and the first end is the return of the nut. The passage is connected to the load path by being inserted into a hole, the second end is located on both sides of the return path, the path is connected to the return path, the load path, the return path and the path are Constitute a return path,
The plurality of rolling members are arranged so as to be able to move into the return path ,
The reflux member has a convex fixing portion formed at the second end,
The lid has contact walls formed on opposite sides of the third story, and a fixing groove formed between the contact wall and the third story,
The return member is characterized Rukoto convex fixing part is positioned fitted into the fixing groove of the lid,
External circulation ball screw.

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