KR100590602B1 - A fabrication method of Nut for Ball screw - Google Patents

Abstract

The present invention relates to a method for manufacturing a nut for a ball screw, which processes two steps of processing a shape by cutting and turning a material, and then injecting a casting into a cylindrical mold.

In the method for manufacturing a ball screw nut according to the present invention, a cast formed by melting carbon steel, which is an alloy of iron (Fe) and carbon (C), into a cylindrical mold is injected into a first step (S100). )Wow; A second step S200 of processing a screw thread on an inner circumferential surface of the nut 100 manufactured in the first step S100; A third step S300 of heat-treating the nut 100 through the second step S200; And a fourth step (S400) of grinding the outer and inner diameters of the nut (100) which has passed through the third step (S300); In the nut 100 in the first step S100, the tube fastening part 120 to which the tube 140 is fastened, the tube assembly hole 150 to which the tube 140 is coupled, and the tube holder 160 are fastened to the nut 100 are fastened. Holder fixing hole 170 is characterized in that it is formed. According to the present invention having such a configuration, there is an advantage that the manufacturing cost of the nut can be reduced by shortening the labor time and working time.

Ball screw, nut, shaft, ball, tube, tube connection part, casting, heat treatment, polishing

Description

A fabrication method of Nut for Ball screw}

1 is a cross-sectional view of a ball screw according to the prior art.

Figure 2 is a schematic process flow diagram of the nut manufacturing process of the ball screw according to the prior art.

Figure 3 is a perspective view of the ball screw with the nut manufactured in accordance with a preferred embodiment of the present invention coupled to the shaft.

Figure 4 is a block diagram showing a manufacturing process according to the nut screw manufacturing method according to the present invention.

5 is a perspective view of a nut manufactured according to the method for manufacturing a nut for a ball screw according to the present invention.

Explanation of symbols on the main parts of the drawings

100. ..... Nut 120. ..... Tube Connection

140. ..... Tube 150. ..... Tube Assembler

160. ..... Tube Holder 170. ..... Holder Fixing Hole

180. ..... wiper fixing hole 200. ..... shaft

S. ..... Screw S100. ..... Step 1

S200. ..... The second step S300. ..... Step 3

S400. ..... Fourth Step

The present invention relates to a manufacturing method, and more particularly, to a method for manufacturing a nut for a ball screw to process a two-step processing of the shape by cutting and turning the material in a single step by injecting a casting into a cylindrical mold. will be.

In general, the ball screw is a mechanical component that operates with the shaft and nut of the screw shaft in between, and serves to convert the rotational movement into linear movement. It is widely used as a feeding mechanism for machinery, aircraft mechanical control devices, or other machinery and devices that require precision.

The ball screw is formed by opposing grooves of semi-circular cross sections on the inner circumferential surface of the nut and the outer circumferential surface of the shaft, respectively, and the grooves of the semi-circular cross-sections are coupled to each other to form a spiral passage. The ball is inserted into the spiral passage formed by the combination of the nut and the shaft, and the shaft is smoothly rotated inside the nut to move forward or backward by performing the predetermined transfer operation. Mechanical parts.

In addition, the nut is equipped with a tube for guiding the ball provided in the helical passage to be returned to the helical passage to be continuously supplied, so that the shaft can be rotated even more smoothly.

1 is a cross-sectional view of a ball screw according to the prior art.

According to this, the ball screw (Ball screw) 1 has a nut (Nut, 10) having a substantially cylindrical shape, the thread is formed on the inner circumferential surface, and a thread corresponding to the inner circumferential surface of the nut 10 is formed on the outer circumferential surface and the A shaft having a round rod shape coupled to the inside of the nut 10 and rotating, and a ball provided between the nut 10 and the shaft 20 to smoothly rotate the shaft 20. Ball, 30) is configured to include.

The nut 10 is formed in a cylindrical shape having a predetermined length, and a flat portion (not shown) is processed on the upper and lower surfaces of the outer circumference. The flat part is provided with a tube (Tube, 14) for guiding the ball (30) to be continuously supplied to the spiral passage (12) formed by coupling the threads of the nut (10) and the shaft (20).

The tube 14 is formed of a metal material and is formed in an approximately 'c' shape. Therefore, both ends are inserted into the tube assembly hole 16 to be described below, and the center portion is coupled so as not to flow in close contact with the flat portion.

In addition, one or two pairs of tube assembly holes 16 to which the tube 14 is inserted and coupled are formed in the planar part to correspond to each other in an oblique direction, and are not shown between the tube assembly holes 16 corresponding to each other. A plurality of holder fixing holes to which the tube holder for fixing the tube 14 is fastened are formed.

In addition, a wiper fixing to which a screw is fastened to fix a circular wiper (not shown) provided to prevent foreign matter from penetrating into the nut 10 on the upper surface of both ends of the flat part. Holes (not shown) are further formed.

Inside the nut 10, a long shaft 20 having a long rod is inserted into and coupled to the nut 10. On the outer circumferential surface of the shaft 20 is formed a screw thread corresponding to the thread formed on the inner circumferential surface of the nut 10 is coupled to each other to form a spiral passage (12).

A metal ball 30 is inserted into the spiral passage 12 so that the shaft 20 can smoothly rotate inside the nut 10. Therefore, the shaft 20 reciprocates the linear movement of forward or backward within the nut 10 by the rolling motion of the ball 30 to perform the transfer operation in the machine tool, etc. to which the ball screw 1 is fastened. Will be executed.

Figure 2 shows a schematic process flow diagram of the nut manufacturing process of the ball screw according to the prior art. According to this, the manufacturing process of the nut 10 begins with a material cutting step (S10) of cutting the round bar-shaped metal material.

The cutting material step (S10) is a step of cutting the metal material to a predetermined length by a sawing machine (Sawing Machine (not shown)), the surface structure of the metal material is formed with a non-uniform or fine cracks, etc. In many cases, it is cut with a margin of about 5 mm of the product outer diameter and length manufactured to remove such a surface.

After the material cutting step (S10), a plurality of tube assembly holes 16, such as to penetrate the inside of the cut round bar to make a cylindrical shape and the flat portion of the outer circumferential upper and lower surfaces and the tube 14 are assembled. The shape processing step (S20) for processing the hole (Hall) is to proceed.

The shape processing step (S20) is performed in a lathe and a milling machine (Machine, not shown), the tube assembly 16 and the tube 14 to which the tube 14 is inserted and coupled. And a step of forming a holder fixing hole to which the tube holder is fixed, and a wiper fixing hole for fixing the wiper provided at both end surfaces to prevent the infiltration of foreign matter in the nut 10.

Then, the thread processing step (S30) for processing the thread on the inner peripheral surface of the nut 10 is to proceed. The screw processing step (S30) is carried out by a bite (Bite) in a CNC lathe (Computer Numerical Control lathe), about 0.3 mm considering the deformation and grinding in the heat treatment step (S40) to be described below It will be processed with a margin of time.

The screw processing step (S30) includes a tapping process of processing a thread in a tapping machine (not shown) in the holder fixing hole and the wiper fixing hole.

In order to protect the threads formed during the tapping process, a heat treatment step S40 is performed in which a heat treatment bulletproof liquid having a gel state is inserted into the holder fixing hole and the wiper fixing hole and then subjected to heat treatment. The heat treatment step (S40) is a process for abrasion resistance and fatigue resistance is subjected to carburization (浸 炭) heat treatment to strengthen the hardness of the surface.

Carburizing heat treatment is a method used to make a carburizing surface of a certain thickness on the entire surface of the part, it is a method to obtain a high hardness on the surface by performing quenching and tempering.

After the heat treatment step (S40), the heat treatment bulletproof solution inserted into the holder fixing hole and the wiper fixing hole is removed, and the tapping process performed in the screw processing step (S30) is performed once more, and then the inner diameter as the finishing step. The polishing step (S50) for polishing the outer diameter and the outside is in progress.

The polishing step (S50) is carried out by dividing the process of grinding the outer diameter and the side and the process of grinding the inner diameter, by being polished according to the shaft 20 dimensions in the grinding machine suitable for the size of the outer diameter and the inner diameter Production of the nut 10 is completed.

On the other hand, although the manufacturing process of the said shaft 20 is not shown, it progresses in the same manner as the manufacturing process of the said nut 10. In other words, the material cutting step of cutting the metal material, the screw processing step for processing the thread on the outer diameter of the round bar, the heat treatment step for heat treatment the round bar and the polishing step to refine the thread.

Here, the heat treatment step of the manufacturing process of the shaft 20, unlike the manufacturing process of the nut 10 is subjected to a high frequency heat treatment. The high frequency heat treatment is a method used to heat only a specific surface portion, and is a method of quenching fine carbon steel on the surface through a high frequency current and spraying cooling water.

In addition, the nut 10 manufacturing process and the shaft 20 manufacturing process are performed in a procedure corresponding to the process at the same time in other equipment to produce the nut 10 and the shaft 20, and the nut 10 manufactured as described above. The ball screw 1 is completed by combining the shaft 20 and inserting the ball 30.

However, the prior art as described above has the following problems.

In the prior art as described above takes a long time in the manufacturing process of the nut (10). That is, the material cutting step (S10) and the shape processing step (S20) are separately performed in the nut 10 manufacturing process of the ball screw 1, so that the number of work maneuvers in the manufacturing process of the nut 10 is increased. It takes a lot of time, and the labor cost and manufacturing cost increases as the labor and time required for such a lot increases, there is a problem that the unit cost of the ball screw (1) increases.

An object of the present invention for solving the above problems is a process for manufacturing a nut for a ball screw to process the two steps of cutting the material and turning to process the shape by injecting a casting into a cylindrical mold. To provide.

In the nut manufacturing method of the ball screw according to the present invention for achieving the above object, a nut formed by injecting a casting formed by melting carbon steel, which is an alloy of iron (Fe) and carbon (C), into a cylindrical mold to produce a nut. A first step of doing; A second step of machining a thread on an inner circumferential surface of the nut manufactured in the first step; A third step of heat-treating the nut passed through the second step; And a fourth step of grinding the outer diameter and the inner diameter of the nut that has passed through the third step.

The nut in the first step is characterized in that a plurality of tube assembly holes for continuously supplying the ball so that the tube is coupled to rotate in the interior.

One side of the outer peripheral surface of the nut is characterized in that the tube fastening portion is formed so that the tube coupled to the tube assembly hole is mounted.

The tube fastening portion is characterized in that a plurality of holder fixing holes to which the tube holder is coupled to secure the tube is formed.

And, one side of the tube fastening portion is characterized in that the wiper fixing hole is further formed to fasten the screw to secure the wiper to prevent foreign matter from penetrating into the inside of the nut.

According to the present invention having such a configuration, there is an advantage that the manufacturing cost of the nut can be reduced by shortening the labor time and working time.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of the method for manufacturing a ball screw nut according to the present invention will be described in detail.

Figure 3 shows a perspective view of the ball screw with the nut manufactured in accordance with a preferred embodiment of the present invention coupled to the shaft.

According to this, the ball screw (Ball screw) is a nut (Nut, 100) of a substantially cylindrical shape, the thread is formed on the inner peripheral surface, the thread corresponding to the inner peripheral surface of the nut 100 is formed on the outer peripheral surface and the nut ( A shaft having a round rod shape coupled to the inside of the rotating shaft 100 and a nut provided between the nut 100 and the shaft 200 to smoothly rotate the shaft 200. Not shown).

The nut 100 is formed of carbon steel, which is an alloy of iron (Fe) and carbon (C), which are frequently used in mechanical parts such as bolts, and structural materials, and more precisely, chromium molybdenum steel (SCM420) or hardening structure guaranteeing structural steels ( SCM420H) is applied.
Then, the nut 100 is formed in a cylindrical shape having a predetermined length, the tube fastening portion 120 is processed on the upper surface of the outer circumference. The tube fastening portion 120 is formed in a plane, and the tube (Tube, 140) for guiding the ball is continuously supplied to the spiral passage formed by coupling the threads of the nut 100 and the shaft 200 is provided. do.

The tube 140 is formed of a metal material and is formed in an approximately 'c' shape. Therefore, both ends of the tube 140 are inserted into the tube assembly hole 150 to be described below, and the central portion is coupled to the tube fastening portion 120 so as not to flow.

In addition, one or two pairs of tube assembly holes 150 to which the tube 140 is inserted and coupled are formed in the tube coupling part 120 to correspond to each other in an oblique direction, and between the tube assembly holes 150 corresponding to each other. There are a plurality of holder fixing holes 170 are fastened to the tube holder 160 for fixing the tube 140, the tube holder 160 is the holder fixing holes (Screw, S) 170 is fastened and coupled.

In addition, the screw (S) is fixed to the upper surface of both ends of the tube fastening portion 120 to fix a circular wiper (not shown) provided to prevent foreign matter from penetrating into the nut 100. The wiper fixing hole 180 to be fastened is further formed.

Inside the nut 100, a long shaft 200 having a round rod is inserted therein. On the outer circumferential surface of the shaft 200 is formed a screw thread corresponding to the thread formed on the inner circumferential surface of the nut 100 is coupled to each other to form a spiral passage.

The spiral passage is inserted into the metal ball so that the shaft 200 can be rotated smoothly in the nut (100). Therefore, the shaft 200 is to reciprocate the linear movement of the forward or backward in the nut 100 by the rolling motion of the ball is to perform the transfer operation in the machine tool, such as the ball screw is fastened.

Figure 4 is a block diagram showing a manufacturing process according to the ball screw nut manufacturing method according to the present invention, Figure 5 is a perspective view of a nut manufactured according to the ball screw nut manufacturing method according to the present invention. .

As shown in these drawings, the manufacturing method of the nut 100 injects a casting formed by melting carbon steel, which is an alloy of iron (Fe) and carbon (C), into a cylindrical mold to manufacture the nut 100. The first step (S100), the second step (S200) for processing the thread on the inner peripheral surface of the nut 100 produced in the first step (S100), and the nut 100 through the second step (S200) And a fourth step (S400) of grinding the outer diameter and the inner diameter of the nut 100 passed through the third step (S300).

The first step (S100) is a cylindrical shape having a predetermined length and penetrates the inside of the cylindrical shape, that is, by coupling the upper and lower ends made by injecting a casting into a mold divided into a top and a bottom, the cylindrical nut 100 In the manufacturing step, the conventional material cutting step and the shape processing step are performed at the same time, the outer shape of the nut 100 and a plurality of holes (Hall) are integrally formed.

Therefore, in the first step (S100), the tube fastening portion 120 is formed on the outer circumferential surface of the nut 100 so that the tube 140 is coupled, the tube fastening portion 120 is Tube 140 is coupled to the tube assembly hole 150 for continuously supplying the ball to be rotated in the nut 100 and the tube holder for fixing the tube 140 is coupled to the tube assembly hole 150 Holder fixing hole 170 is fastened to form 160, and at both ends of the tube fastening part 120, wiper fixing holes 180 fastened with screws S to fix the wipers are processed in molds, respectively. It is formed integrally by injecting castings.

After the outer shape of the nut 100 is formed in the first step S100, a second step S200 of processing a screw thread is performed on an inner circumferential surface through which the nut 100 penetrates.

The second step (S200) is carried out by a bite (Bite) in a CNC lathe (Computer Numerical Control lathe), and the deformation and grinding during the heat treatment in the third step (S300) described below In consideration of this, it is processed with a margin of about 0.3 mm. The second step (S200) includes a tapping process of processing a thread into a tapping machine (not shown) in the holder fixing hole 170 and the wiper fixing hole 180.

Thereafter, in order to protect the threads formed in the tapping process, a third step (S300) of performing a heat treatment after inserting a heat-treated bulletproof liquid in a gel state into the holder fixing hole 170 and the wiper fixing hole 180 is performed. ) Proceeds. The third step (S300) is a process for abrasion resistance and fatigue resistance is subjected to carburization heat treatment to strengthen the surface hardness.

The carburizing heat treatment is a method used to make a carburizing surface having a certain thickness on the entire surface of a part, and is a method of obtaining high hardness on the surface by performing quenching and tempering.

After passing through the third step S300, the heat-treatment bulletproof liquid inserted into the holder fixing hole 170 and the wiper fixing hole 180 is removed and the tapping process performed in the second step S200 is performed once more. Next, as a finishing step, a fourth step S400 of grinding the inner and outer diameters of the nut 100 is performed.

The fourth step (S400) proceeds by dividing the process of grinding the outer diameter and side of the nut 100 and the process of grinding the inner diameter, the shaft 200 in the grinding machine suitable for the size of the outer diameter and the inner diameter By the grinding according to the dimensions of the nut 100 is completed.

On the other hand, the manufacturing method of the shaft 200 coupled with the nut 100 is not shown, but is substantially the same as the manufacturing method of the nut 100 (大同小異). That is, the first step (S100) of the nut 100 is separated as in the prior art is carried out in the material cutting step of cutting the metal material and the screw processing step of processing the thread on the outer diameter of the round bar, and then heat-treating the round bar It proceeds including the heat treatment step and the polishing step to polish the thread.

Here, the heat treatment step of the manufacturing method of the shaft 200, unlike the manufacturing method of the nut 100 is subjected to a high frequency heat treatment. The high frequency heat treatment is a method used to heat only a specific surface portion, and is a method of quenching fine carbon steel on the surface through a high frequency current and spraying cooling water.

In addition, the nut 100 and the shaft 200 manufacturing method are processed in the same process at the same time in other equipment, the nut 100 and the shaft 200 is produced, the nut 100 is produced When combined with the shaft 200 and inserting the ball is the ball screw is completed.

The scope of the present invention is not limited to the above-exemplified embodiments, and many modifications based on the present invention will be possible to those skilled in the art within the above technical scope.

As described in detail above, in the method for manufacturing a ball screw nut according to the present invention, two steps of processing a shape by cutting and turning a material are configured to process casting in a single step by injecting a casting into a cylindrical mold.

Therefore, in manufacturing the ball screw nut, it is expected to reduce the labor and reduce the working time.

In addition, labor cost and manufacturing cost are reduced due to the reduction of labor time and working time, and the manufacturing cost of the ball screw is expected to be reduced.

Claims (5)

A first step of manufacturing a nut by injecting a casting formed by melting carbon steel, which is an alloy of iron (Fe) and carbon (C), into a cylindrical mold; A second step of machining a thread on an inner circumferential surface of the nut manufactured in the first step; A third step of heat-treating the nut passed through the second step; Ball screw nut manufacturing method comprising a fourth step of grinding the outer diameter and the inner diameter of the nut passed through the third step. According to claim 1, wherein the nut in the first step, Ball screw nut manufacturing method characterized in that a plurality of tube assembly holes for continuously supplying the ball to be coupled to the tube is rotatable inside. According to claim 2, On the outer peripheral surface side of the nut, Ball screw nut manufacturing method characterized in that the tube coupling portion is formed so that the tube is coupled to the tube assembly hole is mounted. 4. The method of claim 3, wherein the tube fastening portion has a plurality of holder fixing holes to which the tube holders are coupled to fix the tube. According to claim 4, One side of the tube fastening portion, Ball screw nut manufacturing method characterized in that the wiper fixing hole is further formed to fasten the screw to secure the wiper to prevent foreign matter from penetrating into the nut.

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