JP2009097532A - Externally circulating ball screw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an externally circulating ball screw easy in being manufactured and capable of easily installing the ball screw, maintaining a favorable degree of rotor circulation, and reducing a relative angle of both guides (inlet and outlet) of a circulating device. <P>SOLUTION: The externally circulating ball screw includes a screw, a nut, a rotor and the circulating device. The nut has a hollow structure, is and externally attached to the screw. The rotor is stored in a rotational groove of the screw and a rotary tub of the nut. The circulating device is composed of a cover and a base. A drawing part and a first half-flow passage are formed at the cover. When installing the circulating device, when covering the base with an installation cover in an installation hole for arranging a leg on the nut, the installation of the circulating device can be completed, and since the circulating device can also be manufactured by metal mold injection, the problem of difficulty in manufacturing or installing a conventional circulating device can be improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

The conventional transmission elements are being widely applied in the industrial field. In addition to having a high precision effect as linear feed transmission, the frictional wear rate is small, the energy conversion rate is high, and the noise is small. Needless to say, the ball screw is a machine tool that is applied to various industries because it has the advantage of being highly rigid and difficult to damage.

  As described above, in order to reciprocate the nut on the screw without limitation, it is necessary to install a circulation device so that the rotor is infinitely circulated in the rotation groove. Therefore, for example, US Pat. No. 3,661,030 has been proposed as a conventional circulation device design. However, since any of the return paths of the circulation device has a bent portion, when the rotor rotates at a high speed, the rotor continues to collide with the claw portion or the bent portion (impact portion) of the return path. As a result, the strength of the part is weakened, and as a result, the debris of the reflux element peeled off by the collision is sandwiched between the rotors, so that the circulation smoothness of the rotor is affected and the circulation device is destroyed. However, it is one of the factors of the revocation situation often seen in ball screws.

  Therefore, in order to solve the above-described problems, the industry submits a design for inserting a curved pipe into a screw rail from a tangential direction as a solution. For example, the design method of the circulation device in US Pat. No. 3,971,264 is a combination of multistage curved pipes, and the curved pipes are a combination system, so that the structure is unstable. Also, since the tube hole direction of the nut is the direction of the lead angle, when processing the tube hole, if the position of the nut is not rotated using a multi-axis processing machine, it will be processed to the required hole part. Therefore, the degree of processing difficulty is further increased.

  Further, in the circulation device of US Pat. No. 4,953,419, since the bent pipe is provided with both bent return passages, it is difficult to control the manufacturing size of the bent portion. Problems relating to the processing method have the same problems as the above-mentioned application. Further, the fixing method of the circulating device is also fixed by a fixing piece on the outer diameter of the nut. The fixing method is unstable and the outer diameter of the nut is increasing.

Further, the circulation device of USP2003 / 0213323 is composed of a plurality of members in a combined manner, and requires many molds according to the necessity of the members. The mounting time for the combination must also increase. In addition, when the number of members necessary for the circulation device increases, the rotor inside the circulation device is likely to vibrate between the members during high-speed rotation, and an unknown noise is likely to be generated.

Furthermore, the above three tangential type external circulation devices have a common problem. When the circulating device is mounted on the nut, it is difficult to align, and when installing the curved pipe, the curved pipe is inserted into a mounting hole larger than the curved pipe. Since there is always a gap, foreign matter or dust can easily enter the inside of the nut from this gap, affecting the smoothness of the ball screw circulation, and in a severe case, damaging the ball screw.

  In order to solve the above problems and to make the structure of the circulation device simpler, the industry further developed a circulation device of US Pat. No. 7,040,189 to change the conventional metal conduit to a plastic molding method, The same accessories are used as the structure, but the following problems exist when the application is evaluated.

The structure of the circulation device is a combination of two pieces on the left and right sides, and the plastic accessory is widely opened on both the left and right sides due to a collision with the bent part of the ball, which may result in insufficient strength. In addition, foreign matter is likely to enter the ball screw through the gap between the two members. In relation to the tangential type external circulation device, the inlet / outlet of the circulation device is relatively 180 degrees (shown in FIG. 2 (A) of the application), so that the outer diameter of the nut is required to be large. Furthermore, the depth of the nut mounting hole (for mounting both feet of the circulation device) is relatively deep and the machining depth is deeper, so the cutter or machine base is insufficiently rigid. This is likely to cause a machining error with respect to the mounting hole, and the number of rotors located at the portion where the load is applied is relatively reduced.
US Pat. No. 3,661,030 US Pat. No. 3,971,264 US Pat. No. 4,953,419 U.S. Pat. No. 7,040,189

  In view of the above-mentioned problems of the conventional circulation device, the present inventor has been able to produce an invention that can achieve the following objects after study and improvement.

  An object of the present invention is to shorten the mounting time of a ball screw that is easy to manufacture and easy to mount a circulation device.

  Next, an object of the present invention is to maintain the smoothness of the rotor circulation by securely fixing the circulation device on the nut.

  Furthermore, it aims at making the relative angle of both guide parts (entrance / exit) of a circulation device small.

  In order to achieve the above object, an external circulation type ball screw according to the present invention includes a screw, a nut, a rotor, and a circulation device. A rotating groove is installed on the outer edge of the screw, the nut has a hollow structure, and is placed on the screw, and a rotating tub is installed on the inner edge of the hollow structure, and the inner edge of the nut is provided with a flat surface. A plurality of mounting holes and a plurality of fixing holes are installed on the top, and the rotor is accommodated between the rotation groove of the screw and the nut rotation tank.

  The circulation device includes a cover and a base, and the cover covers the base.

  Extending portions are installed at both ends of the cover, and a first half channel and two first contact surfaces are installed on one side of the base. A first mating surface is installed so as to be adjacent to both sides of the first half channel, and a first combination surface is installed so as to be adjacent to the inner side of the first contact surface. The first combination surface and the first mating surface are perpendicular to each other, and a recess is provided at a position opposite to the first contact surface, and a through-hole penetrating the first contact surface is provided on the recess. To do.

  The base portion is provided with a foot portion with respect to the extending portion and a second half passage with respect to the first half passage. The foot part is provided with a claw part for guiding the rotor, the claw part protrudes into the rotation groove of the screw and is positioned and fixed, and the second combination surface is installed on both sides of the base part with respect to the first combination surface. And the plane with respect to the nut of a base installs the 2nd contact surface.

  Furthermore, when the cover covers up to the base part, the circulation device can be combined independently without the need for a fixing member in accordance with the interference between the first combination surface and the second combination surface. And the extending portion form a guide portion, and the first half-flow path and the second half-flow path form a reflux path, and at the same time, a first contact surface and a second contact surface are formed. To do. In addition, the first mating surface and the second mating surface can be bonded together to prevent foreign matter from entering the reflux path.

  As described above, the circulating device after combining the guide parts is attached to the mounting holes of the nuts and aligned with each other by the geometric outer shape, and at the same time, the pawl part of the guide part by the planar contact between the bearing surface and the nut. Will be inserted into the rotation groove of the nut. Further, the stator passes through the cover through hole and is fixed together with the nut fixing hole. The head of the stator is housed in the recess and the circulation device can be tightly tightened on the nut.

  The point to be explained here is that the relative angle of both guide portions (rotor entrance / exit) of the circulation device in the present invention is smaller than 180 degrees, so that the depth of the mounting hole of the nut is that of the conventional mounting hole. It is shallower than the depth, the mounting hole can reduce errors when machining, the outer diameter of the nut is smaller than the conventional one, and most importantly, the number of rotors located in the part where the load is applied is increased . The circulation device is manufactured by an injection molding method and can be produced quickly.

Finally, in order to clearly describe the implementation features of the present invention, as described below, the present invention will be described in terms of the inventive step or practical method.
1. The nut is easy to process and can be processed using conventional processing machines.
2. The circulation device is based on mold injection molding and can be mass-produced.
3. The relative angle of both guides is less than 180 degrees.
4). The number of rotors located at the load site is increased, and the rigidity of the ball screw can be improved.
5). The depth of the nut mounting hole is shallow, and there is no error during processing of the mounting hole due to insufficient rigidity of the tool or machine base during processing.
6). The outer diameter of the nut can be reduced to meet client requirements.
7). The circulation device according to the present invention is a system formed by combining the upper and lower sides, and is further tightened firmly on the nut by a stator, so that there is no fear of insufficient strength due to the impact of the rotor.
8). By matching the geometrical outline of the guide portion of the circulation device and the mounting hole of the nut, there is no gap between them, and no foreign matter enters the nut.

  For a better understanding of the features and technical contents of the present invention, refer to the implementation method and the drawings according to the present invention. However, the implementation method or drawings are merely used for explaining or referring to the present invention, and there is no limitation on the present invention.

  In the first embodiment of the present invention, as shown in FIGS. 1 to 6, the present invention is an external circulation type ball screw.

  A screw 1 with a rotating groove 11 on the top, a hollow structure, a rotating tub 22 with respect to the rotating groove 11 on the inner edge, and a reciprocating motion on the screw 1; A flat surface 21 is installed on the outer edge, a plurality of mounting holes 211 and a plurality of fixing holes 212 are opened on the flat surface 21, and the mounting holes are formed from the nut 2 penetrating the flat surface 22, the rotating tub 22 and the rotating groove 11. A plurality of rotors X accommodated in the rotation path, and a circulation device 3 that includes a cover 3A and a base 3B, and the cover 3A covers the base 3B.

  At both ends of the cover 3A, an extending portion 31A is installed, and a first half channel 32A and two first contact surfaces 36A are installed on one side with respect to the base 3B. The first mating surface 33A is installed so as to be adjacent to both sides of the first half channel 32A, and the first combination surface 35A is installed so as to be adjacent to the inside of the first contact surface 36A. The first combination surface 35A and the first mating surface 33A are perpendicular to each other, and a recess 34A is installed at a position opposite to the first bearing surface 36A, and the first bearing surface 36A is disposed on the recess 34A. Through-holes 341A are opened.

  The base portion 3B is provided with a foot portion 31B for the extending portion 31A and a second half channel 32B for the first half channel 32A. The foot portion 31B is provided with a claw portion 311B that guides the rotor X, the claw portion 311B projects into the rotation groove 11 of the screw 1 and is positioned and is fixed to both sides of the base portion 3B with respect to the first combination surface 35A. The second combination surface 35B is installed, and the flat surface 21 of the base portion 3B with respect to the nut 2 installs the second contact surface 34B.

  Furthermore, when the cover 3A covers the base 3B, the circulating device 3 can be combined alone without using a fixing member in accordance with the interference between the first combination surface 35 and the second combination surface 35B. After the combination, the guide portion is formed by the foot portion 31B and the extending portion 31A, and the relative angle R of both guide portions is smaller than 180 degrees (as shown in FIG. 6), and the bottom surface 30 of both guide portions. Are positioned on the same plane, and the outer contour of the guide portion is the same as the inner contour of the mounting hole 211 of the nut 2. The first half flow path 32A and the second half flow path 32B form a reflux path, and the cross section of the reflux path is a circular cross section, and at the same time, the normal of the circular cross section of the outer contour of the circular cross section The thickness is not uniform with respect to the direction. A first contact surface 36A and a second contact surface 34B form a contact surface. The first mating surface 33A and the second mating surface 33B can be bonded together to prevent foreign matter from entering the reflux path. The return path of the guide part is parallel to the angle of the spiral angle of the rotation path and is installed in the tangential direction of the spiral of the rotation path, and the return path of both guide parts is not installed in parallel.

  The above description is the detailed description of each member and the mutual relationship. Hereinafter, an implementation method of the present embodiment will be described.

  As described above, in the circulation device 3 after the combination, the guide portion is mounted in the mounting hole 211 of the nut 2 and is aligned with each other by the geometrical shape of the guide portion and the mounting hole. By contact with the two flat surfaces 21, the claw portion 311 </ b> B of the guide portion is also fitted into the rotating groove 11 of the screw 1. Further, the stator G passes through the through hole 341 </ b> A of the cover 3 </ b> A and is fixed together with the fixing hole 212 of the nut 2. The head of the stator G is accommodated in the recess 34A, and the circulation device 3 can be firmly tightened on the nut. Then, the return path of the circulation device 3 is connected to the rotation path, and the rotor X enters the return path by the guidance of the claw portion 311B of the guide portion, and further enters the rotation path from the other end of the return path. Infinite circulation between the nut 2 and the screw 1 is possible.

  Further, as shown in FIGS. 7 and 8, the second embodiment of the present invention is different from the first embodiment except that the cover 3A is mainly provided with receiving grooves 38A at both ends thereof. . A cover plate 37A is provided on the accommodation groove 38A, and a through hole 381A is opened at a relative position between the inside of the cover plate 37A and the first half channel 32A. The storage tank 38A accommodates the lubricating body 4, and a part of the lubricating body 4 penetrates the through hole 381A and protrudes outside the first half channel. Since the lubrication effect of the rotor X can be achieved by contacting with the lubricating body 4 when the rotor X is in operation, the original size of the ball screw can be obtained without adding an extra lubrication device to the ball screw. Is preserved.

  As described above, the external circulation type ball screw of the present invention has a circulating device that overcomes the problems of the prior art due to its precise design, and the ball screw is manufactured more quickly and is expected to be used. The effect is achieved and the rigidity of the ball screw can be improved. Therefore, it is clear that the present invention already has “industrial applicability”, and the technical features disclosed in the examples are not disclosed in the publications before the application, and Since it cannot be used for the public and has not only the fact that the effect is enhanced, but also the enhancement of the additional effect cannot be overlooked, the present invention can be applied to any of “novelty” and “inventive step”. Since it meets the requirements for patents, it is expected that it will be granted early through examination by filing an application by law.

  Further, the disclosure of the embodiments described above is for explaining the present invention, and does not limit the present invention. Therefore, any of numerical changes, replacement of equivalent elements, etc. are all within the scope of the present invention. Belonging to.

The three-dimensional view of the external circulation type ball screw of this invention. The exploded view of the external circulation type ball screw of the present invention. Sectional drawing of the external circulation type ball screw of this invention. The exploded view of the circulation device of the present invention. The exploded view of the circulation device of the present invention. The side view of the screw and circulation device of the present invention. The three-dimensional figure of the cover of the circulation apparatus of the 2nd Example of this invention. The fitting sketch of the cover and rotor of the circulation apparatus of 2nd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screw 11 Rotating groove 2 Nut 21 Plane 211 Mounting hole 212 Fixing hole 22 Rotating tank 3 Circulating device 30 Bottom surface 3A Cover 31A Extending part 32A First half flow path 33A First mating surface 34A Concave 341A Through hole 35A First Combined surface 36A First contact surface 37A Cover plate 38A Receiving groove 381A Through hole 3B Base portion 31B Foot portion 311B Claw portion 32B Second half flow path 33B Second mating surface 34B Second contact surface 35B Second combined surface 4 Lubricant X Rotor G Stator R Relative angle of both guides

Claims (5)

A screw having a rotation groove on its outer peripheral surface;
It has a hollow structure and is provided with a rotating tank corresponding to the rotating groove on the inner edge, and is provided so as to reciprocate on the screw, and a plurality of mounting holes are opened on a plane provided on the outer edge A nut through which the mounting hole penetrates the plane;
A plurality of rotors accommodated in a rotation path formed from the rotation tank and the rotation groove;
A circulation device attached to the nut, comprising a cover and a base, the cover covering the base;
Both ends of the cover are each provided with an extending portion, and the first half channel and the first combined surface are installed on one side with respect to the base portion,
The base is provided with a foot for the extending portion, a second semi-flow channel for the first semi-flow channel, and a second combination surface for the first combination surface, respectively. The claw part that guides the rotor is installed, and the claw part protrudes into the rotation groove of the screw and is inserted and positioned, and after combining the circulation device, the extension part and the foot part form a guide part and guide The part is attached to the mounting hole of the nut, and the reflux paths of both guide parts are not installed in parallel, and the reflux path is formed by the first half channel and the second half channel. External circulation type ball screw.   The bottom surfaces of the guide portions are located at the same plane in the rotor entrance and exit, and the angle of the rotor entrance and exit of both guide portions with respect to the screw axis direction is smaller than 180 degrees. The external circulation ball screw described.   2. The external circulation type ball screw according to claim 1, wherein the return path of the guide unit is installed along a tangential direction of a spiral line of the rotation path in parallel with a spiral angle of the rotation path.   The cross section of the reflux path is a circular cross section, and the thickness thereof is not uniform with respect to the normal direction of the circular cross section of the outer periphery of the circular cross section. External circulation type ball screw.   The cover is provided with a lubrication body, and a part of the lubrication body protrudes from the return path, and when the rotor has been operated, the lubrication effect of the rotor can be achieved by contacting the lubrication body. The external circulation type ball screw according to claim 1.

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