JP2862097B2 - Method and apparatus for passing a pipe to be polished - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention prevents the occurrence of sagging at the front end and the rear end when polishing the outer peripheral surface of a material to be polished such as a steel pipe. The present invention relates to a pipe passing method and apparatus for making the surface condition of the pipe substantially uniform in the longitudinal direction.

[Prior Art] When a steel pipe is used for an application utilizing the metallic surface properties, the surface is polished and shipped. In particular, stainless steel pipes are often used for decorative purposes where polishing is essential.

Conventionally, when polishing the outer peripheral surface of the steel pipe, for example, as shown in FIG. 2, for increasing the efficiency of polishing work, along the moving direction of the steel pipe P are arranged a plurality of abrasive wheel a ₁ ~a ₃ in series Uses polishing equipment. Grinding wheel a ₁ ~a ₃ is rotated at a high speed while pressed against them main top surface to the steel pipe P. Also, as the roller r ₁ ~r ₃ sends to the opposite side of the grinding wheel a ₁ ~a ₃ disposed, sandwiching the steel pipe P in each set of grinding wheel a ₁ ~a ₃ and the feed roller r ₁ ~r ₃ It is configured.

The steel pipe P to be polished rotates with the arrow D while rotating about the axis.
Conveyed in the direction. At this time, the peripheral portion of the grinding wheel a ₁ ~a ₃ is pressed against the outer peripheral surface of the steel pipe P by friction and sliding, the steel pipe P
Is polished.

In FIG. 2, polishing in which the rotating surfaces of the polishing wheels a _{1 to} a ₃ are set parallel to the transport direction D of the steel pipe P, that is, vertical polishing is performed. Alternatively, the polishing wheel a _{1 in the} transport direction D
Holding the rotating surface of the ~a ₃ at right angles, there is also a case where the horizontal polishing attaching a polishing marks in the circumferential direction of the steel pipe P.

In this type of polishing operation, various proposals have been made in order to finish the surface properties after polishing uniformly.
For example, Japanese Utility Model Publication No. Sho 61-31805 discloses a method in which a grinding wheel follows a shape change of a steel pipe by incorporating a copying mechanism. In addition, 63-2291
Patent Document 3 discloses a pipe grinding apparatus that incorporates a holding mechanism that regulates the amount of pressing of a holding roller in accordance with a grinding allowance.

[Problems to be Solved by the Invention] In a conventional polishing apparatus, steel pipes, which are materials to be polished, are fed one by one to positions where they come into contact with a polishing wheel. That is, as shown in Figure 3, in a state where there is a gap G between the tip portion of the steel pipe P ₂ and a subsequent trailing end of the steel pipe P ₁ of the preceding, the steel pipe P ₁ by the rotation of the feed roller r, P ₂ is carried out.

For this reason, the contact state of the grinding wheel a with the longitudinal center and both ends of the steel pipes P ₁ and P ₂ is different, and the polished surface becomes uneven. In particular, since the outer peripheral edge of the polishing wheel a suddenly collides with the tip of the steel pipe, the tip of the steel pipe is easily polished excessively. In addition, since the polishing is performed in a state where the polishing wheel a is in contact with the end face of the steel pipe, a rounded corner is generated. Similarly, excessive polishing and dripping are inevitable at the rear end of the steel pipe.

In addition, since the outer peripheral edge of the grinding wheel a suddenly comes into contact with the end surface on the tip side of the steel pipe, the load applied to the grinding wheel a increases.
As a result, when a polishing wheel is used in which emery paper or the like cut into strips is mounted in the circumferential direction, the impact force causes the emery paper to be torn off. Also, in the case of a polishing wheel coated with abrasive grains, the abrasive grains fall off. This tendency is particularly strong when longitudinal polishing is performed by setting the rotating surface of the polishing wheel to be parallel to the transport direction of the steel pipe. For this reason, the deterioration of the grinding wheel progresses, and it is required to frequently replace the grinding wheel.

The present invention has been devised in order to solve such a problem, and it has been found that the polishing wheel is kept in constant contact with the tube to be polished over its entire length including the front end and the rear end of the tube to be polished. An object of the present invention is to improve the durability of a wheel and to perform uniform polishing on the outer peripheral surface of a pipe to be polished.

[Means for Solving the Problems] The pipe passing method of the present invention, in order to achieve the object, when polishing the outer peripheral surface of the pipe to be polished while feeding a plurality of pipes to be polished along a transport line, With the tip of the succeeding tube being polished pressed against the rear end of the preceding tube to be polished, the polishing wheel is relatively moved from the rear end outer peripheral surface of the preceding tube to be polished to the distal end outer surface of the subsequent tube to be polished. It is characterized by the following.

Further, a pipe passing apparatus for carrying out this method includes an upstream motor that drives an upstream feed roll disposed upstream of the polishing wheel along the transport direction of the pipe to be polished, and a rotation of the upstream feed roller. A number control signal and an upstream control circuit input to the upstream motor; a downstream motor driving a downstream feed roll disposed downstream of the polishing wheel; and controlling a rotation speed of the downstream feed roller. A downstream control circuit for inputting a signal to the downstream motor, wherein when the butting portion of the preceding pipe to be polished and the subsequent pipe to be polished passes through the polishing wheel, the number of rotations of the upstream feed roller is adjusted. A comparison arithmetic unit for outputting a control signal for maintaining the rotation speed of the downstream-side feed roller higher than that of the downstream-side feed roller is provided between the upstream-side control circuit and the downstream-side control circuit.

[Operation] In the present invention, as shown in FIG.
P ₁ and subsequent steel pipe P ₂ is fed into a polishing apparatus abutted the rear end portion and a distal end with each other, in contact with the grinding wheel a. Therefore, the contact state of the grinding wheel a to the steel pipe P _1, P _2, different from the case of FIG. 3, without the outer peripheral edge of the grinding wheel a on the distal end surface and rear end surface of the steel pipe P _1, P ₂ are in contact , Steel pipe
Under substantially the same conditions as the central part in the longitudinal direction of P ₁ and P ₂ , the steel pipes P ₁ and P ₂
Coming into contact with the edge outer peripheral surface of the P _2. Therefore, the polishing of the ends of the steel pipes P ₁ and P ₂ is performed in the same manner as the polishing of the central part in the longitudinal direction, thereby preventing excessive polishing and dripping that tend to occur at the ends of the steel pipes.

[Examples] Hereinafter, the present invention will be specifically described with reference to examples.

In the present embodiment, the steel pipes P ₁ and P ₂ were laterally polished using a pipe passing apparatus whose main parts are shown in FIG. As the polishing apparatus, along the conveying direction D of the steel pipe P as shown in FIG. 2 conventional polishing apparatus in which a plurality of grinding wheel a ₁ ~a ₃ in series, or developers present inventors separately Any of the polishing apparatuses in which a plurality or a single polishing wheel is arranged in a circumferential direction at a part of the steel pipe in the longitudinal direction can be used.

Prior steel is brought into contact with the distal end surface of the succeeding steel pipe P ₂ on the rear end surface of the P ₁ and for transporting the steel pipe P _1, P _2, upstream of the grinding wheel a along the conveying direction D of the steel pipe P _1, P ₂ In addition, transport mechanisms C ₁ and C ₂ that are independently driven and controlled are provided on the downstream side.

The transport mechanisms C ₁ and C ₂ include feed rollers R ₁ and R ₂ , respectively. The feed rollers R ₁ , R ₂ are driven by motors M ₁ , M ₂ , and feed the steel pipes P ₁ , P ₂ in the transport direction D by their rotational force. Motors M ₁ and M ₂ receive control signals s ₁ and S ₂ from control circuits S ₁ and S ₂ , respectively.
s ₂ is input, the control signal s _1, s ₂ rollers R ₁ sends a rotational speed corresponding to, tell R _2.

Between the upstream control circuits S ₁ and the downstream-side control circuit S ₂ is connected to the comparison computing unit CPU. Comparison operation unit CPU transmits control signals s _1, s ₂ are compared, and so alter the contents of the control signal s _1, s ₂ depending on the longitudinal position relationship of the steel pipe P _1, P ₂ with respect to the polishing wheel a I have.

Prior polishing of the steel pipe P ₁ is almost finished, the rear end portion approaches the grinding wheel a, a rear end portion thereof is detected by the position detector T. The detection signal is input from the detector T to the comparison operation unit CPU. Then, lowering relative rotational speed of the downstream side feed roller R _2, increasing relative rotational speed of the upstream side feed roller R _1.
Subsequent steel Thereby, than the feed velocity V ₁ of the preceding steel pipe P ₁
Increased feeding speed V ₂ of the P ₂ is pressed against the distal end of the succeeding steel pipe P ₂ to the rear end of the preceding steel pipe P _1.

In this case, if too large a difference between the speed V ₂ and the feed feedrate V _1, a force to press the trailing steel pipe P ₂ the prior steel pipe P ₁ during polishing is increased, there is a possibility that an adverse effect on polishing. Therefore, it is assumed that there is no slip between the feed rollers R ₁ and R ₂ and the steel pipes P ₁ and P _2, and the difference between the feed speed V ₁ and the feed speed V ₂ is represented by V ₂ −
Preferably, V ₁ ≦ 1 m / min.

After the leading end of the succeeding steel pipe P ₂ to the rear end of the preceding steel pipe P ₁ is in contact with subsequent steel pipe P ₂ is sent toward the grinding wheel a while slip between the feed roller R _1. It acts on the succeeding steel pipe P ₂ sliding friction as a reaction force generated at this time, maintains the butted state between the preceding steel pipe P ₁ and the succeeding steel pipe P _2.

The rear end of the preceding steel pipe P ₁ in this butting condition and the subsequent steel pipe P ₂
Is polished by the polishing wheel a. Therefore, both the rear end portion and the front end portion are polished in the same manner as the central portions in the longitudinal direction of the steel pipes P ₁ and P ₂ . Moreover, the prior order rear end side and the outer peripheral edge of the grinding wheel a on the tip side of the succeeding steel pipe P ₂ of the steel pipe P ₁ is not able to friction and sliding, excessive polishing and sagging on the end of the steel pipe P _1, P ₂ Does not occur. Moreover, since it is no hit suddenly outer peripheral edge of the grinding wheel a the distal end of the succeeding steel pipe P _2, also reduced damage grinding wheel a.

After the rear end of the preceding steel pipe P ₁ has passed through the grinding wheel a, relatively increased rotational speed of the downstream side feed roller R _2, relatively reduce the rotational speed of the upstream-side feed roller R _1. As a result, the leading steel pipe
And feeding speed V ₁ of the P ₁ becomes higher than the feed speed V ₂ of the succeeding steel pipe P _2, leading steel pipe P ₁ is sent to the above, the steel pipe P _1, P ₂ mutually abutting state is released.

Subsequent steel pipe P ₂ is polished in contact with the grinding wheel a in this state. Subsequent steel pipe Consequently, the prior steel pipe P ₁ without rotation of the succeeding steel pipe P ₂ is restricted, under the conditions desired set
It can be polished P _2.

Thereafter, the plurality of sequentially fed steel pipes are polished while sequentially changing the feed speeds V ₁ and V ₂ in this manner.

Next, operating conditions when a stainless steel pipe having an outer diameter of 114.3 mm, a thickness of 2 mm, and a length of 4,000 mm is laterally polished are shown.

As the grinding wheel, as introduced by the present inventors in Japanese Utility Model Publication No. 59-24462, a plurality of strip-shaped emery papers radially mounted on a shaft were used. The polishing wheel was pressed against the outer peripheral surface of the stainless steel tube with a pressing force of 40 kgf / cm ² while rotating at a peripheral speed of 40 m / sec.

Stainless steel tube to be polished while rotating at a rate of 183 rotation, was fed to the polishing apparatus at an average feed rate V ₁ 2.3 m / min. When the trailing end of the preceding steel pipe P ₁ has been detected by the position detector T, lowering the feed speed V ₁ in 2.0 m / min. On the other hand, the feed rate V ₂ of the succeeding steel pipe P ₂ remains at the initial value.
Maintained at 2.3 m / min. As a result, subsequent steel pipe P in the prior steel pipe P _1
2 was pressed, and the steel pipes P ₁ and P ₂ passed through the grinding wheel a with no gap between the rear end face of the preceding steel pipe P _{1 and} the front end face of the subsequent steel pipe P ₂ .

When the rear end face of the preceding steel pipe P ₁ has passed through the grinding wheel a, it increases the feed rate V ₁ in 2.3 m / min, downstream the leading steel pipe P ₁ is released from the butt state between the distal end surface of the succeeding steel pipe P ₂ Sent out to the side. Then, while maintaining the feed rate V ₂ to 2.3 m / min, polishing was carried out for a subsequent steel pipe P _2.

Polishing was performed while passing through the polishing wheel a with the end faces of the steel pipes P ₁ and P ₂ abutted in this way. The polished steel pipes P ₁ and P ₂ were finished to have a substantially uniform surface over their entire length. Was done. Also, no sagging of the steel pipe end rounded due to polishing did not occur. On the other hand, the polishing wheel could be sufficiently used continuously even after being used for polishing 20 steel pipes.

For comparison, as shown in FIG. 3, individual steel pipes P ₁ ,
The P ₂ in contact with a polishing wheel with independent state through tube, the other was subjected to grinding in the same condition. At this time, in the range of about 30 mm from the end of the polished steel pipe, excessive polishing was observed at both the front end and the rear end. In addition, sagging that caused polishing failure occurred at a rate of one out of four. At this time, even if the same grinding wheel was used, after embossing the 20 steel pipes, several pieces of emery paper were cut off at several places, making it unusable for use.

In the above in the embodiment has been described a case of changing the feeding speed V ₁ of the preceding steel pipe P _1. However, the present invention is not restricted to this, and when the end of the steel pipe passes through the grinding wheel, the speed difference V is maintained so that the rear end face of the preceding steel pipe and the front end face of the subsequent steel pipe are kept in abutting condition. ₂ −V ₁
It is also possible to change the feeding speed V ₂ of the succeeding steel pipe P _2.
Alternatively, the rotational speed of the upstream feed roll R ₁ may be steadily set to be higher than the rotational speed of the downstream feed roll R ₂ , and a plurality of steel pipes may be continuously conveyed in a state where the end faces abut each other. good.

[Effects of the Invention] As described above, in the present invention, in a state where the rear end surface of the preceding polished tube and the front end surface of the subsequent polished tube are abutted, the preceding polished tube and the subsequent polished tube are combined. It is conveyed and polished in contact with the polishing wheel. Therefore, the state of contact of the polishing wheel with the end of the pipe to be polished does not substantially change from the central part in the longitudinal direction, and a uniform polished surface can be obtained over the entire length of the pipe to be polished. In addition, the life of the polishing wheel becomes longer.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a main part of a pipe passing apparatus used in an embodiment of the present invention, and FIG. 2 shows a case where a steel pipe is polished by a plurality of polishing wheels arranged in series along a conveying direction. FIG. 3 is a view for explaining a conventional pipe passing method. a: grinding wheel, P _1, P _2: steel tube C _1, C _2: transport mechanism, M _1, M _2: Motor S _1, S _2: the control circuit, R _1, R _2: Feed roller T: position detector , CPU: comparison operation unit s ₁ , s ₂ : control signal

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B24B 5/36 B24B 5/38

Claims (2)

(57) [Claims] When polishing the outer peripheral surface of a pipe to be polished while feeding a plurality of pipes to be polished along a transport line, the tip of the pipe to be polished is pressed against the rear end of the pipe to be polished. A polishing wheel is relatively moved from a rear end outer peripheral surface of the preceding polishing target tube to a front end outer peripheral surface of the subsequent polishing target tube. 2. An upstream motor for driving an upstream feed roll disposed upstream of a polishing wheel along a transport direction of a pipe to be polished, and a signal for controlling a rotation speed of the upstream feed roller is transmitted to the upstream side. An upstream control circuit for inputting to the motor, a downstream motor for driving a downstream feed roll disposed downstream of the polishing wheel, and a signal for controlling the rotation speed of the downstream feed roller are input to the downstream motor. An upstream control circuit is provided, and when the abutting portion of the preceding pipe to be polished and the subsequent pipe to be polished passes through the polishing wheel, the rotational speed of the upstream feed roller is made larger than the rotational speed of the downstream feed roller. And a comparison arithmetic unit for outputting a control signal for maintaining a large value between the upstream control circuit and the downstream control circuit.