The present invention relates to a nut for a ball screw, and more particularly, to a nut with a dual-narrowed path so as to reduce the increment of temperature, resistance and weight, and increase precise positioning and life of use.
The ball screws are used in the movable platforms of high-precision machines and are important parts for precision industry.
The conventional ball screw 90 is rotated to linearly transmit a nut 910 mounted to the ball screw 90 and heat is generated during the transmission due to friction between the nut 910 and the ball screw 90. The maximum temperature is located at the center of the nut 90 wherein the balls 952 are in contact with, the maximum temperature area is designated as the max-temp area 910A. As show in
When the temperature of the nut 910 is increased, the heat affects the length of the nut 910 so that it cannot be precisely positioned and the precision of positioning of the system fails. It is obvious that the temperature affects the precision and the positioning so that the nut 901 needs to be reduced.
The present invention intends to provide a nut for ball screws and the nut improves the shortcomings of the conventional nuts.
The present invention relates to a nut for a ball screw. It comprises:
a nut having an outer surface and a threaded path defined, through the nut, and
multiple dual-narrowed paths located between the threaded path and the outer surface of the nut, the dual-narrowed paths defined through a central axis of the nut and substantially being parallel, to the threaded path, each of the dual-narrowed paths having a high-speed area and two low-speed areas, the high-speed area located between the two low-speed areas, a diameter of each of the dual-narrowed paths being reduced from two ends toward the high-speed area:
multiple micro fans disposed in the dual-narrowed paths so as to drive air flows in the dual-narrowed paths to reduce temperature;
a control portion to control operation of the micro fans; and
multiple temperature sensing portions disposed between the threaded path and the outer surface of the nut to sense temperature, the control portion connected with the temperature sensing portions so as to individually control the micro fans.
The primary object of the present invention is to provide a nut for a ball screw to reduce the increment of temperature, resistance and weight, and increase precise positioning and life of use.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.
Referring to
About the nut 10, it comprises an outer surface 12 and a threaded path 11 which is defined through the nut 10.
With regard to the multiple dual-narrowed paths 20, they are located between the threaded path 11 and the outer surface 12 of the nut 10, and the dual-narrowed paths 20 are defined through the central axis of the nut 10 and substantially being parallel to the threaded path 11. Each of the dual-narrowed paths 20 has a high-speed area 20A and two low-speed areas 20B, wherein the high-speed area 20A is located between the two low-speed areas 20B. The diameter of each of the dual-narrowed paths 20 is gradually reduced from two ends (the low-speed areas 20B) toward the high-speed area 20A. As shown in
Concerning the multiple micro fans 30, they are disposed in the dual-narrowed paths 20 so as to drive air flows in the dual-narrowed paths 20 to reduce temperature.
About the control portion 40, it is provided to control operation of the micro fans 30.
About the multiple temperature sensing portions 60, they are disposed between the threaded path 11 and the outer surface 12 or the nut 10 to sense temperature. The control portion 40 is connected with the temperature sensing portions 60 so as to individually control the micro fans 30.
In detail, the nut 10 is threadedly mounted to the ball screw 51 by the threaded path 11 and multiple balls 52 are located between the nut 10 and the ball screw 51 By rotating the ball screw 51, the nut 10 moves linearly. The balls 52 are generally located between the nut 10 and the ball screw 51 consecutively, as shown in
As shown in
As shown in
Because the nut is used for precision transmission so that it does not bear load, the dual-narrowed paths 20 do not affect the strength of the nut and reduces the weight of the nut 10 as well. The required input energy is also reduced because of the light in weight.
When the temperature of the nut 10 increases, the heat effect affects the length of the nut 10 and affects the positioning of the system. Therefore, by the dual-narrowed paths 20, the temperature of the nut 10 is reduced when it moves so that the precision for positioning is increased and the impact of heat affect can also he reduced. The life of use is prolonged (the factors affecting the life of use includes the temperature of friction and lubricant oil, viscosity of the lubricant oil reduces when the temperature increases and the film of the lubricant oil breaks, and this may result in burn). Also, the dual-narrowed paths 20 are able to reduce the temperature of the lubricant oil.
As shown in
Furthermore, in order to increase the total contact area (to enhance the heat transfer effect each of the dual-narrowed paths 20 can further comprise multiple recesses 21 defined in the inner periphery thereof As shown in
The forms of the recesses 21 can be different instead of axially straight slots as shown in
As shown in
As shown in
The recesses 21 increase the contact area with the air when the air passes through the dual-narrowed paths 20. The larger the contact area is, the larger amount heat is brought away by the air. The contact area that the dual-narrowed paths 20 increase is the sum of the sides of each of the recesses 21.
In addition, as shown in
Referring to
As shown in
The nut 10 uses micro fans 30 to generate convection to reduce temperature that raises due to friction during the process of the linear movement of the nut 10 when the ball screw 51 is rotated. The micro fans 30 in the dual-narrowed paths 20 generate the air flows to reduce the temperature at the max-temp area 10A of the nut 10. Besides, the dual-narrowed paths 20 with the recesses 21 generate different air flows and increase the contact area between the air flows and the dual-narrowed paths 20. The efficiency for bringing heat away is increased.
Because the nut 10 is used for precision transmission so that it does not bear load, the dual-narrowed paths 20 do not affect the strength of the nut 10 and the weight of the nut 10 is reduced as well. The required input energy is also reduced because of the light in weight.
When the temperature of the nut 10 is increased, the heat affects the length of the nut 10 so that it cannot be precisely positioned and the precision of positioning of the system fails. The present invention uses micro fans 30 to generate air flows to keep the temperature of the nut 10 to reduce the errors due to high temperature and the precision of positioning and the life of use are increased.
While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.
Number | Date | Country | Kind |
---|---|---|---|
100223108 | Dec 2011 | TW | national |