JP2009103200A - Nut rotation type ball screw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To equalize axial load born by a bearing outer ring and a nut and axial load born by the nut and a screw. <P>SOLUTION: A second rotor (a roller or a roller cone) 4 is used as a transmission media between the bearing outer ring 3 and the nut 2, and load capacity born by line contact thereof is made higher than characteristics of point contact. Consequently, the axial load capacity born by the bearing outer ring 3 and the nut 2 can reach predetermined load capacity of the ball screw and working life can be improved by combining with the axial load capacity born by the nut 2 and the screw 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a nut rotating ball screw, and more particularly to a nut rotating ball screw in which a roller (roll cone) is used as a transmission medium between a bearing outer ring and a nut.

  The nut rotation type ball screw is formed by integrally forming a nut and a bearing outer ring, and the bearing outer ring is fixed to a work table. The power motor transmits the power to the nut with a belt, so that the nut rotates relative to the screw. Rotational torque can be linked to the work table instead of axial movement. It is possible to select a motor that can be supplied at high speed and can be driven at a low speed even if it is used as a ball screw that is fixed to a screw and has no inertial force when the screw rotates and has a large slenderness ratio. Since the present invention is widely applied mainly to semiconductor machines, woodworking machines, conveyors, etc., it is needless to say that the present invention is actually important as an industrial application machine.

  Until now, as shown in FIG. 1, the conventional nut rotary ball screw mainly comprises a screw 1, a nut 2 and a bearing outer ring 3, and a plurality of rotors 5 are provided between the screw 1 and the nut 2. A plurality of balls 4 are provided between the nut 2 and the bearing outer ring 3.

  As described above, the conventional nut-rotating ball screw has a structure in which the effective number of balls of the rotor 5 (indicating the number of rotors that can be loaded) is increased between the screw 1 and the nut 2. The load capacity received with the nut 2 can also be increased relatively. However, the number of balls 4 provided between the nut 2 and the bearing outer ring 3 cannot be increased. By increasing only the outer diameter of the ball 4, the axial direction in which the space between the bearing outer ring 3 and the nut 2 can be received. And an axial load capacity that can be received between the nut 2 and the screw 1 can be blended. However, in such a solution system, the outer diameter of the bearing outer ring 3 is large, and the ball screw does not meet the specifications of the machine base. In addition, since the increase in the outer diameter of the ball 4 is limited to a certain level, the load capacity in the axial direction is also limited. Therefore, unless the above problems are solved, the nut rotating ball screw cannot reach the intended load capacity. In severe cases, the service life is reduced.

  In view of the circumstances described above, the present inventor has continually devised and researched based on his many years of professional experience and knowledge, and the present invention for improving the above problems of the prior art has been researched and developed.

  Based on the problems of the conventional nut-rotating ball screw, the present inventors have been able to achieve the following objects of the present invention through research and improvement.

  That is, an object of the present invention is to be able to mix an axial load capacity that can be received mainly between the bearing outer ring and the nut and an axial load capacity that can be received between the nut and the screw.

  In order to achieve the above-mentioned object, the present invention provides a nut rotary ball screw having a first rotary groove on an outer peripheral surface thereof, a screw on the screw, and an inner edge portion of the first rotary groove. A first rotating tub is provided for one rotating groove, a nut having a plurality of second rotating tubs provided on the outer edge, and a nut mounted on the nut, with respect to the second rotating tub on the inner edge. A plurality of first rotors mounted between a bearing outer ring provided with a second rotation groove and between the first rotation groove and the first rotation tank, wherein the screw and the nut can be relatively spirally moved. And a reflux element mounted on the nut and provided with a reflux path for providing an infinite circulation of the first rotor, and mounted between the second rotating tank and the second rotating groove, The nut and the outer ring of the bearing can rotate relative to each other; Contact between the rolling tank and the second rotary groove surface includes a plurality of second rotor becomes linear contact state, the. The first rotor is preferably a ball. Further, the first rotor may be a roller. On the other hand, the second rotor is preferably a roller. Further, the second rotor may be a roll cone.

  Since the contact between the surface of the second rotor and the surfaces of the second rotating tank and the second rotating groove is in a line contact state, the load capacity received by the line contact is a point contact. (Because the conventional technology uses a ball, the ball and the rotating surface are in a point contact state) Due to the greater characteristics, the axial load capacity received between the bearing outer ring and the nut and the space between the nut and the screw are received. The axial load capacity can be combined with each other to improve the service life. In other words, the present invention is a nut rotation type ball screw, and conventionally, the ball is used as a transmission medium between the nut and the outer ring of the bearing, and as the number of rotors between the screw and the nut increases, In the case where the ball screw also has an increased ability to receive an axial load, it is to improve that the ball screw cannot receive the load only by the ball between the outer ring and the nut of the bearing. Therefore, the present invention uses a roller or a roll cone as a transmission medium between the bearing outer ring and the nut, and the load capacity received by the line contact is larger than the characteristic of the point contact, so that the bearing outer ring and the nut The axial load capacity that can be received between the nut and screw can achieve the desired load capacity of the ball screw by combining the axial load capacity that can be received between the nut and screw, and the service life of the ball screw Can be improved. That is, it is possible to increase the load capacity received between the bearing outer ring and the nut without increasing the outer diameter of the bearing outer ring, thereby increasing the load capacity between the bearing outer ring and the nut between the nut and the screw. By making it equivalent to the load capacity, the load capacity of the nut rotary ball screw can be improved as a whole, and therefore the service life can be improved.

  In order to more clearly describe the implementation features of the present invention, the present invention has an inventive step over the prior art and describes its practical form.

  The nut rotation type ball screw of the present invention has a load capacity in the axial direction that can be received from the conventional point contact state because the contact between the outer ring of the bearing and the second rotor between the nut is in a line contact state. large. In addition, it is not necessary to increase the outer diameter of the second rotor, and the axial load capacity that can be received between the screw and the nut can be blended, and there is no problem due to an increase in the outer diameter of the bearing outer ring.

  For a better understanding of the features and technical contents of the present invention, refer to the embodiments and drawings of the present invention. However, this embodiment or drawing is for explanation or reference, and is not a limitation on the present invention.

(Embodiment)
As shown in FIGS. 2 and 3, the embodiment of the present invention is a nut rotation type ball screw, and includes a screw 1 provided with a first rotation groove 11 on an outer peripheral surface, and a screw 1 on the screw 1. A nut 2 in which a first rotating tub 21 is provided with respect to the first rotating groove 11 at an inner edge thereof and a plurality of second rotating tubs 22 are provided at an outer edge thereof; A bearing outer ring 3 that is provided (fitted) on the inner edge and provided with a second rotation groove 31 with respect to the second rotation tank 22 at the inner edge thereof, and the first rotation groove 11 and the first rotation tank 21. The screw 1 and the nut 2 are mounted on the plurality of first rotors 5 that can move relatively in parallel, and the nut 2 is mounted on the first rotor 5, and the infinite circulation of the first rotor is performed on the first rotor 5. The reflux element 6 provided with the reflux path 61 for providing, the second rotating tank 22 and the second A plurality of second rotors 4 that are attached between the rotary grooves 31 and that allow the nut 2 and the bearing outer ring 3 to move relatively in a linear manner (or simply rotational motion). Use a roller (shown in FIG. 2) or a roll cone (shown in FIG. 3) as media.

  The surface of the second rotor 4 and the surfaces of the second rotary tank 22 and the second rotary groove 31 are in a line contact state, and the load capacity received by the line contact is a point contact (conventional technology). Since the ball is used, the contact between the ball and the rotating surface is a point contact state), the load capacity in the axial direction received between the nut 2 and the bearing outer ring 3, and the screw 1 And the nut 2 can be combined with the axial load capacity received (that is, by making both loads equal), the service life can be improved.

  In conclusion, according to the present invention, the load capacity received by the line contact is larger than that of the point contact, so that the axial load capacity received between the bearing outer ring 3 and the nut 2 is the same as the outer diameter of the bearing outer ring 3. It is improved without increasing, and the improved load capacity and the axial load capacity received between the nut and the screw are blended with each other (so that they are equivalent), and the predetermined load capacity of the ball screw And at the same time improving its life. Accordingly, the present invention has no doubt that it already has “industrial applicability”, and the technical features disclosed in the present embodiment are not disclosed in the publications before the application. In addition, the present invention is not 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. Are all in accordance with the requirements of patents, so it is expected that they will be filed by law and granted early through examination.

  Further, the disclosure of the embodiment described above is for explaining the present invention, and does not limit the present invention. Therefore, any of numerical changes, replacement of equivalent elements, and the like are included in the scope of the present invention. Belonging to.

A sketch of the prior art of a nut rotating ball screw. 1 is a sketch of a nut rotary ball screw shown as an embodiment of the present invention, and shows an example in which a roller is provided as a transmission medium between a bearing outer ring and a nut. FIG. 10 is a sketch of a nut rotating ball screw shown as another example of an embodiment of the present invention, and a sketch showing an example in which a roll cone is provided as a transmission medium between a bearing outer ring and a nut.

Explanation of symbols

(Conventional technology)
1 screw 2 nut
3 Bearing outer ring 4 Ball,
5 Rotor (present invention)
DESCRIPTION OF SYMBOLS 1 Screw 11 1st rotation groove 2 Nut 21 1st rotation tank 22 2nd rotation tank 3 Bearing outer ring 31 2nd rotation groove 4 2nd rotor 5 1st rotor 6 Returning element 61 Return path 51 Fitting part 511 Lead angle

Claims (5)

A screw provided with a first rotation groove on its outer peripheral surface;
A nut provided on the screw, provided with a first rotating tub with respect to the first rotating groove at an inner edge, and provided with a plurality of second rotating tubs at an outer edge;
A bearing outer ring provided on the nut and provided with a second rotation groove on the inner edge with respect to the second rotation tank;
A plurality of first rotors mounted between the first rotating groove and the first rotating tank, wherein the screw and the nut can be relatively spirally moved;
A return element mounted on the nut and provided with a return path for providing infinite circulation of the first rotor;
The nut is mounted between the second rotating tub and the second rotating groove, the nut and the bearing outer ring can be relatively rotated, and the surface thereof, the second rotating tub and the The contact with the surface of the second rotary groove includes a plurality of second rotors that are in a line contact state, and the nut rotary ball screw characterized by the above.   The nut rotary ball screw according to claim 1, wherein the first rotor is a ball.   The nut rotary ball screw according to claim 1, wherein the first rotor is a roller.   The nut rotary ball screw according to claim 1, wherein the second rotor is a roller.   The nut rotary ball screw according to claim 1, wherein the second rotor is a roll cone.

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