JPH04115860A - Method and device for passing the pipe to be polished - Google Patents

Abstract

PURPOSE:To improve the durability of a polishing wheel and perform a uniform polishing finish for the outer peripheral face of the pipe to be polished, by relatively translating the polishing wheel to the tip outer peripheral face of a succeeding pipe to be polished from the rear end outer peripheral face of a preceding pipe to be polished. CONSTITUTION:A succeeding steel pipe P2 is fed toward a polishing wheel (a) while causing slide in the space with a feeding roller R1, after the tip of a succeeding steel pipe P2 abutting onto the rear end of a preceding steel pipe P1. The slide friction generated at this time acts on the succeeding steel pipe P2 as the reaction force, and the abutted state of the preceding steel pipe P1 and succeeding steel pipe P2, is maintained. In this abutted state the rear end of the preceding pipe P1 and the tip of the succeeding pipe P2 are polished by the polishing wheel (a). After the rear end of the preceding pipe P1 passing through the polishing wheel (a), the rotation number of a downstream side feeding roller R is relatively increased, and that of the upperstream side feeding roller R1 is relatively decreased. The succeeding pipe P2 is polished with its contact with the polishing wheel (a) in this state.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for polishing the outer peripheral surface of a material to be polished such as a steel pipe.
The present invention relates to a tube passing method and device that prevents wobbling from occurring at the tip and rear ends and makes the surface condition after polishing substantially uniform in the longitudinal direction.

[Prior Art] When steel pipes are used for applications that take advantage of their metallic surface properties, their surfaces are polished before being shipped. In particular, stainless steel pipes are often used for decorative purposes, etc., which require polishing work.

Conventionally, when polishing the outer peripheral surface of a steel pipe, for example, a second
As shown in the figure, in order to increase the efficiency of polishing work, steel pipe P
A polishing device is used in which a plurality of polishing wheels a + -ax are arranged in series along the moving direction of the polishing wheels. Polishing wheels a1-a
, rotate at high speed with their main upper surfaces pressed against the steel pipe P. Further, feed rollers r1 to r3 are arranged on the opposite side of the polishing wheels a1 to a3, and the steel pipe P is sandwiched between each set of the polishing wheels a1 to a3 and the feed rollers r1 to r3.

The steel pipe P to be polished is conveyed in the direction of the arrow while rotating around its axis. At this time, the peripheral portions of the polishing wheels a1 to a are pressed against the outer circumferential surface of the steel pipe P to rub and slide, and the outer circumferential surface of the steel pipe P is polished.

In FIG. 2, polishing is performed in which the rotating surfaces of the polishing wheels 81 to a3 are set parallel to the transport direction of the steel pipe P, that is, vertical polishing. Alternatively, horizontal polishing may be performed in which the rotating surfaces of the polishing wheels a, to a3 are held perpendicular to the transport direction and polishing marks are left in the circumferential direction of the steel pipe P.

In this type of polishing work, various proposals have been made to achieve a uniform surface quality after polishing. For example, Japanese Utility Model Publication No. 61-31805 introduces a method in which a polishing wheel follows changes in the shape of a steel pipe by incorporating a copying mechanism. Also, Jikko 63
Japanese Patent No. 12913 discloses a vibrator grinding device incorporating a presser mechanism that regulates the amount by which the presser roller is pressed down in accordance with the grinding allowance.

[Problem to be solved by the invention] In conventional polishing equipment, the steel pipe that is the material to be polished is
- Books are fed one by one into a position where they come into contact with the polishing wheel. That is, as shown in FIG. 3, with a gap G between the rear end of the preceding steel pipe P1 and the distal end of the following steel pipe P2, the steel pipes P, P2 are conveyed by the rotation of the feed roller r. will be held.

Therefore, the state of contact of the polishing wheel a with the longitudinal center and both ends of the steel pipes p, , p is different, and the polished surface becomes non-uniform. 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 likely to be excessively polished. Furthermore, since polishing is performed with the polishing wheel a in contact with the end face of the steel pipe, rounded corners occur. Similarly, excessive polishing and sagging are unavoidable at the rear end of the steel pipe.

Moreover, since the outer circumferential edge of the polishing wheel a suddenly comes into contact with the end surface on the distal end side of the steel pipe, the load that the polishing wheel a receives increases. As a result, when using a polishing wheel to which strips of emery paper or the like are attached in the circumferential direction, the emery paper is torn off by the impact force. Furthermore, in the case of a polishing wheel coated with abrasive grains, the abrasive grains may fall off. especially,
This tendency becomes stronger when vertical polishing is performed with the rotating surface of the polishing wheel set parallel to the conveying direction of the steel pipe. Therefore, the deterioration of the polishing wheel progresses, and it is required to frequently replace the polishing wheel.

The present invention was devised in order to solve these problems, and it makes the contact state of the polishing wheel with respect to the tube to be polished constant over the entire length of the tube, including the tip and rear ends, and polishes the tube. The purpose is to improve the durability of the ring and to achieve a uniform polishing finish on the outer peripheral surface of the tube to be polished.

[Means for Solving the Problems] In order to achieve the object, the tube selection method of the present invention polishes the outer circumferential surface of the tubes to be polished while feeding them along a conveyance line. Relatively moving a polishing ring from the rear end outer circumferential surface of the preceding polished tube to the distal end outer circumferential surface of the subsequent polished tube while pressing the tip of the subsequent polished tube against the rear end of the polished tube. It is characterized by

Further, the tube selection device 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 tube to be polished, and a rotation speed of the upstream feed roller. an upstream control circuit that inputs a control signal to the upstream motor, a downstream motor that drives a downstream feed roll disposed downstream of the polishing wheel, and a signal that controls the rotation speed of the downstream feed roller. and an upstream control circuit that inputs the rotation speed of the upstream feed roller to the downstream motor when the abutting portion of the preceding polished tube and the subsequent polished tube passes through the polishing wheel. The present invention is characterized in that a comparator is provided between the upstream control circuit and the downstream control circuit for outputting a control signal that maintains the rotation speed higher than the rotation speed of the downstream feed roller.

[Function] In the present invention, as shown in FIG.
, and the following steel pipe P2 are fed into the polishing device with their rear ends and front ends butted against each other, and come into contact with the polishing wheel a. Therefore, the polishing wheel a for the steel pipes p, , p
The contact state of the steel pipes p, , p, is different from that in Fig. 3.
The outer circumferential edge of the polishing wheel a does not come into contact with the front end surface or the rear end surface of the polishing wheel a, but contacts the outer circumferential surfaces of the end portions of the steel pipes PI and P2 under substantially the same conditions as the longitudinal center portions of the steel pipes P+ and Pg. Therefore, polishing of the ends of the steel pipes p, , p is performed in the same manner as polishing of the central part in the longitudinal direction, and excessive polishing and sagging that tend to occur at the ends of the steel pipes are prevented.

[Example] Hereinafter, the present invention will be specifically explained with reference to Examples.

In this example, the steel pipes P+ and R2 were laterally polished using a pipe passing device whose main parts are shown in FIG. The polishing device may be a conventional polishing device in which a plurality of polishing wheels a1 to a3 are arranged in series along the transport direction of the steel pipe P, as shown in FIG. 2, or a steel pipe separately developed by the inventors. It is possible to use any polishing device in which a plurality of polishing wheels or a single polishing wheel are disposed circumferentially in a part of the longitudinal direction of the polishing device.

In order to transport the steel pipes p+, pa by bringing the tip end face of the following steel pipe P2 into contact with the rear end face of the preceding steel pipe P1, the steel pipes PI, P,
on the upstream and downstream sides of the polishing wheel a along the conveyance direction of
Transport mechanisms C, , C, each of which is driven and controlled independently, are provided.

The conveyance mechanisms C, , C, each have feed rollers R1 and R2.
It is equipped with The feed rollers R,,R, are driven by motors M,...
It is driven by M, and its rotational force sends the steel pipes p,,p, in the transport direction. Motors M, M2 have control circuits S,
, S, to the control signal S1. S2 is input, and the control signal S
The rotation speed corresponding to ++S2 is transmitted to the feed rollers R,,R,.

The upstream control circuit Sl and the downstream control circuit S2 are connected through a comparator CPU. The comparator CPU compares the control signals S I+ S z and changes the content of the control signal S ++ S z according to the longitudinal positional relationship of the steel pipes P+ and P- with respect to the polishing wheel a.

When the polishing of the preceding steel pipe P1 is almost completed and the rear end approaches the polishing wheel a, the position detector T detects the rear end. The detection signal is input from the detector T to the comparator CPU. Then, the rotation speed of the downstream feed roller R2 is relatively lowered, and the rotation speed of the upstream feed roller R1 is relatively increased. As a result, the feed rate (2) of the succeeding steel pipe P2 becomes thicker than the feed rate (1) of the preceding steel pipe P1, and the tip of the succeeding steel pipe P is pressed against the rear end of the preceding steel pipe P1.

At this time, if the difference between the feed rate vl and the feed rate V2 is too large, the force pressing the succeeding steel pipe P against the preceding steel pipe P1 being polished increases, which may adversely affect the polishing. Therefore, feed rollers Rl, Rt and steel pipes p, , p,
Assuming that there is no slippage between the two, it is preferable that the difference between the feed speed V and the feed speed V is set to V, -V, 51 m7 minutes.

After the tip of the succeeding steel pipe P2 comes into contact with the rear end of the leading steel pipe P, the succeeding steel pipe P2 is sent toward the polishing wheel a while slipping between it and the feed roller R1. The sliding friction generated at this time acts as a reaction force on the succeeding steel pipe P2, and maintains the abutting state between the preceding steel pipe P and the succeeding steel pipe P2.

In this butt state, the rear end of the preceding steel pipe P1 and the following steel pipe P
2 is polished by a polishing wheel a. Therefore,
Both the rear end portion and the front end portion are polished in the same manner as the longitudinal center portion of the steel pipe P1°R2.

In addition, because the outer periphery of the polishing wheel a does not rub or slide against the rear end side surface of the preceding steel pipe P1 or the front end side surface of the succeeding steel pipe P2, excessive polishing or sagging occurs at the ends of the steel pipes p, , p. I have nothing to do. Moreover, a polishing ring a is attached to the tip of the succeeding steel pipe P2.
Since the outer peripheral edge of the polishing wheel a does not suddenly hit the polishing wheel a, damage to the polishing wheel a is also reduced.

After the rear end of the preceding steel pipe PI passes the polishing wheel a, the rotation speed of the downstream feed roller R2 is relatively increased, and the rotation speed of the upstream feed roller R1 is relatively lowered. As a result, the feed rate V1 of the preceding steel pipe P1 is changed to the feed rate ■2 of the succeeding steel pipe P2.
becomes larger, the preceding steel pipe P is sent first, and the steel pipe p
,,p, the mutual matching state is canceled.

In this state, the succeeding steel pipe P2 contacts the polishing wheel a and is polished. Therefore, the rotation of the succeeding steel pipe P2 is not restricted by the preceding steel pipe P1, and the succeeding steel pipe P2 can be polished under predetermined conditions.

Thereafter, while sequentially changing the feed speeds V, , V, in this manner, a plurality of steel pipes that are sent one after another are polished.

Next, the outer diameter is 114.3 mm, the wall thickness is 2 mm, and the length is 4.0 mm.
The operating conditions when horizontally polishing a 00 mm stainless steel pipe are shown below.

As for the polishing wheel, the present inventors proposed the
As introduced in the publication, we used a plurality of strips of emery paper arranged in a radial pattern and attached to a shaft. While rotating this polishing wheel at a circumferential speed of 40 m/sec, a pressing force of 40 kg f/cm was applied to the outer peripheral surface of the stainless steel pipe.
” and pressed it.

The stainless steel tube to be polished was fed into the polishing apparatus at an average feed rate of V12.3 m/min while rotating at a speed of 183 revolutions per minute. Then, when the rear end of the preceding steel pipe P1 is detected by the position detector T, the feed rate ■1 is increased to 2.0.
m/min. On the other hand, the feed rate v2 of the subsequent steel pipe P2 was maintained at the initial value of 2.3 m/min. the result,
The following steel pipe P2 was pressed against the preceding steel pipe P, and the steel pipes P+ and P2 passed through the polishing wheel a with no gap between the rear end surface of the preceding steel pipe P1 and the front end surface of the following steel pipe P2.

When the rear end surface of the leading steel pipe P passes the polishing wheel a, the feed rate ■1 is increased to 2.3 m/min, the state of contact with the leading end face of the trailing steel pipe P2 is released, and the leading steel pipe P is moved downstream. I sent him to the side. Then, the subsequent steel pipe P2 was polished while maintaining the feed rate (2) at 2.3 m/min.

In this way, steel pipe P1. When polishing was performed while passing the polishing wheel a with the end faces of the pipes abutted against each other, the polished steel pipes p, , p were finished with a substantially -like surface over their entire length. Furthermore, no sagging caused by rounding of the ends of the steel pipes due to polishing occurred. On the other hand, the polishing wheel is 2
Even after using it for polishing 0 steel pipes, it was possible to use it continuously.

For comparison, as shown in FIG. 3, individual steel pipes P1.
Pt was passed through the tube in contact with a polishing wheel in an independent state, and polishing was performed under the same conditions. At this time, excessive polishing was observed in both the tip and rear ends within a range of about 30 mm from the polished end of the steel pipe. In addition, sagging, which caused poor polishing, occurred in one out of four pieces. At this time, even with the same polishing wheel, after polishing 20 steel pipes, the emery paper was torn in multiple places, making it unusable.

In addition, in the above embodiment, the case where the feed rate (2) of the preceding steel pipe P was changed was explained. However, the present invention is not limited to this, and the speed difference V , -V, it is also possible to change the feed rate ■2 of the succeeding steel pipe P2. Alternatively, the rotation speed of the upstream feed roll R1 is constantly made larger than the rotation speed of the downstream feed roll R2,
A plurality of steel pipes may be continuously conveyed with their end faces abutted against each other.

[Effects of the Invention] As explained above, in the present invention, the preceding tube to be polished and the subsequent tube to be polished are polished in a state where the rear end surface of the preceding tube to be polished and the front end surface of the subsequent tube to be polished are butted against each other. It is transported and brought into contact with a polishing wheel to be polished. Therefore, the contact state of the polishing wheel with the end portion of the tube to be polished is not substantially different from the center portion in the longitudinal direction, and a uniform polished surface can be obtained over the entire length of the tube to be polished. Moreover, the life of the polishing wheel is also extended.

[Brief explanation of the drawing]

Figure 1 shows the main parts of the pipe passing device used in the embodiments of the present invention, and Figure 2 shows a steel pipe being polished by a plurality of polishing wheels arranged in series along the transport direction. This is a diagram for explaining the conventional pipe passage method. a: Polishing wheel C,, C,: Transport mechanism S,, s,: Control circuit T: Position detector S l+ S z: Control signal p,, p2: Steel pipe M,, M,・Motor R,, R, :Feed roller cpv: Comparison calculator

Claims (2)

[Claims] (1) When polishing the outer circumferential surface of a plurality of tubes to be polished while feeding them along a conveyance line, with the tip of the subsequent tube to be polished pressed against the rear end of the preceding tube to be polished, A method for passing a tube to be polished, characterized by relatively moving a polishing ring from the outer peripheral surface of the rear end of the preceding tube to be polished to the outer peripheral surface of the distal end of the subsequent tube to be polished. (2) An upstream motor that drives an upstream feed roll placed upstream of the polishing wheel along the transport direction of the tube to be polished, and a signal that controls the rotation speed of the upstream feed roller to the upstream motor. an upstream side control circuit that inputs an input, a downstream side motor that drives a downstream side feed roll arranged downstream of the polishing wheel, and an upstream side that inputs a signal that controls the rotation speed of the downstream side feed roller to the downstream side motor. and a control circuit, when the abutting portion of the preceding pipe to be polished and the subsequent pipe to be polished passes through the polishing wheel, the rotation speed of the upstream side feed roller is set to be higher than the rotation speed of the downstream side feed roller. A pipe passing device for a pipe to be polished, characterized in that a comparator for outputting a control signal to be maintained is provided between the upstream side control circuit and the downstream side control circuit.