TWI606197B - External circulation ball screw - Google Patents

Description

External circulation ball screw

The invention is a linear transmission element, in particular an outer circulation type ball screw.

For example, the circulation device of US Pat. No. 7,040,189 changes the conventional metal conduit to plastic molding, and the structure is two identical pieces on the left and right sides. However, the patent has the following problems after evaluation: (1) The structure of the circulation device For the combination of the left and right, it is easy to open the plastic parts to the left and right sides due to impact and other factors at the corners of the ball, so the strength will be insufficient. Moreover, the foreign matter easily invades the inside of the ball screw from the gap between the two components. (2) The circulation device is a tangentially-circulating structure, and therefore, the inlet and outlet of the circulation device are relatively 180 degrees (as shown in Figure 2(A) of the patent), so the nut needs a larger outer diameter, and the screw The mounting hole of the cap (which is installed for the two foot portions of the circulation device) has a relatively deep depth. Due to the deep processing depth, the rigidity of the tool or the machine table is easily insufficient, so that the mounting hole is processed with errors, and the load can be located at the load. The rolling elements (between the screw and the nut) are relatively reduced. Especially for small-sized ball screws (small-size ball screws refer to the diameter of the rolling elements is not more than 1mm), the structural design is not applicable, so the prior art is necessary for improvement.

In view of the above problems, the main object of the present invention is to develop a circulation structure suitable for a small-sized ball screw, in particular, an outer circulation type ball screw.

In order to achieve the above object, the present invention is an outer circulation type ball screw, comprising: a long shaft having a spiral rolling groove on the outer edge surface thereof; and a nut provided for the long shaft to be worn a hole, a surface of the inner edge of the perforation is provided with a rolling groove opposite to the rolling groove, the rolling groove and the rolling groove form a load path, and the nut is provided with two through holes arranged at intervals on the outer edge surface and communicating with the hole And a groove communicating with the two through holes; a plurality of rolling members disposed on the load path, the rolling member having a diameter of 0.3 to 1 mm; and a circulating member having a shape of a groove and a through hole, the circulation member is provided with a return path connected to the load path, the return path and the load path form a circulation path; wherein the center of the long axis and the end point of the return channel are connected to a virtual line segment The angle formed by the line segment and the axis passing through the center of the circle is defined as an advancing angle, and the angle of the advancing angle is between 70 degrees and 80 degrees.

Preferably, the angle of advancement angle is preferably 75 degrees.

Therefore, according to the definition of the advancing angle, the small-sized ball screw can reduce the outer diameter of the nut and maintain its rigidity, and the outer diameter of the nut is larger as the current advance angle is smaller. Therefore, the design of the present invention can improve the current problems faced by the small-sized ball screw and maintain the original performance, but can reduce the overall volume of the nut by 30% compared with the original before the improvement.

1‧‧‧ long axis

11‧‧‧ rolling groove

2‧‧‧ nuts

21‧‧‧Perforation

211‧‧‧ rolling groove

22‧‧‧through hole

23‧‧‧ Groove

3‧‧‧Rolling parts

4‧‧‧Recycling parts

41‧‧‧ Return Road

A‧‧‧Advance angle

P‧‧‧ return path endpoint

X‧‧‧ axis

D‧‧‧ Center

The first figure is a system diagram of the outer circulation type ball screw of the present invention.

The second figure is a combination diagram of the outer circulation type ball screw of the present invention.

The third figure is a cross-sectional view 1 of the outer circulation type ball screw of the present invention.

The fourth figure is a cross-sectional view 2 of the outer circulation type ball screw of the present invention.

The fifth figure is a schematic diagram of the impact force caused by the rolling elements at different positions of the circulation path when the advancing angle of the outer-circulating ball screw is 75 degrees.

The sixth figure is a schematic diagram of the impact force caused by the rolling elements at different positions of the circulation path when the advancing angle of the outer-circulating ball screw is 80 degrees.

Referring to the first to fourth figures, the present invention is an external circulation type ball screw comprising: a long axis (1) having a spiral rolling groove (11) on the outer edge surface thereof; a cap (2) provided with a through hole (21) through which the long axis (1) is pierced, and an inner edge surface of the through hole (21) is provided with a rolling groove (211) opposite to the rolling groove (11), the rolling The groove (11) and the rolling groove (211) form a load path, and the nut (2) is provided with two through holes (22) spaced apart from each other and communicating with the through hole (21) on the outer edge surface, and one and two a through hole (22) communicating with the groove (23); a plurality of rolling members (3) disposed on the load path, the rolling member (3) having a diameter of 0.3 to 1 mm; a circulation member (4), The utility model is disposed in the shape of a groove (23) and a through hole (22). The two ends of the shape of the crucible are inserted into the through hole (22), and the circulation member (4) is provided with a connection to the load path. a return path (41), the return path (41) and the load path form a circulation path; wherein the center of the long axis (1) (D) and the end point (P) of the return channel (41) Connecting a virtual line segment, the angle between the line segment and the axis (X) passing through the center of the circle (D) is defined as The advance angle (A), the angle of advancement angle (A) is between 70 degrees and 80 degrees, and the angle of advancement angle (A) is preferably 75 degrees, which defines 75 degrees as the best angle because of its snail Both the outer diameter of the cap and the rigidity of the nut are optimal, and the impact force caused by the rolling member (3) entering the circulating member (4) is much smaller than the case where the advancing angle (A) is 80 degrees, such as the fifth As shown in the figure and the sixth figure, when the advancing angle (A) is 75 degrees, the maximum impact force caused by the rolling member (3) is 0.35 N, and when the advancing angle (A) is 80 degrees, the rolling The maximum impact force caused by piece (3) is 16N.

In view of the above, the "industrial availability" of the present invention should be unquestionable. In addition, the feature technology disclosed in the embodiment of the present invention has not been seen in publications before the application, nor has it been disclosed. The use of not only has the fact that the effect is improved as described above, but also has an additional effect that cannot be neglected. Therefore, the "novelty" and "progressiveness" of the present invention have been met. Li laws and regulations, 提出 legally filed an application for invention patents, prayed for review and early grant of patents, and it was really sensible.

The above description of the embodiments is intended to be illustrative of the invention and is not intended to limit the scope of the invention.

1‧‧‧ long axis

2‧‧‧ nuts

22‧‧‧through hole

23‧‧‧ Groove

3‧‧‧Rolling parts

4‧‧‧Recycling parts

41‧‧‧ Return Road

A‧‧‧Advance angle

P‧‧‧ return path endpoint

X‧‧‧ axis

D‧‧‧ Center

Claims (2)

The utility model relates to an outer circulation type ball screw, which comprises: a long shaft, the outer edge surface is provided with a spiral rolling groove; a nut is provided with a perforation for the long shaft, and the inner edge surface of the perforation is provided The rolling groove and the rolling groove form a load path with respect to the rolling groove of the rolling groove, and the nut is provided with two through holes arranged at intervals on the outer edge surface and communicating with the through hole, and a concave communicating with the two through holes a plurality of rolling elements disposed on the load path, the rolling member having a diameter of 0.3 to 1 mm; a circulating member having a shape formed in the groove and the through hole, the circulating member being disposed a return path connected to the load path, the return path and the load path forming a circulation path; wherein the center of the long axis and the end point of the return channel are connected to a virtual line segment, and the line segment passes through the center of the circle The angle formed by the axis is defined as the advancing angle, and the angle of the advancing angle is between 70 degrees and 80 degrees. The recirculating ball screw of claim 1, wherein the angle of advancement angle is optimally 75 degrees.