JPS5959344A - Constant bead height grinding finishing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the surface finishing of weld beads and the like, and particularly to a grinding device and method suitable for finishing the beads of butt welds of pipes.

Conventionally, finishing of weld beads and the like has been carried out by controlling the pressure applied during grinding using a manual grinder or even in automatic grinding using a torque motor. FIG. 1 shows the configuration of an automatic grinding device using a torque motor.

In this device, the drive motor 3 transmits rotation to the grinding unit 2 using a pulley mechanism or the like to grind the object 1 to be ground, but the rotation speed of the drive motor 3 is transmitted to the rotation speed detector 7 by a gear 5.6. , the voltage v2 that resonates with the output voltage 4 of the rotation speed detector and the predetermined rotation speed set by the rotation speed indicator 12 is 'amplifier C.
19, and the torque motor 8 automatically increases or decreases the pressing force applied by the grinding section 2 to the workpiece l by the difference voltage 7521, and controls the grinding rotation speed to always be constant. be done.

However, the pressing force control to keep the grinding rotation speed constant is to follow the unevenness of the grinding surface.9 If the ground surface before grinding has unevenness, the finished surface will also be uneven. Therefore, it has been impossible to perform uniform finish grinding without any unevenness, regardless of the unevenness before grinding.

In order to solve the above problem, the present invention provides a method and apparatus for uniformly grinding a pipe base material by following the surface shape of the pipe base material, regardless of the irregularities of the weld bead.

Focusing on the fact that the load during grinding is determined by the pressing force (vertical direction) on the workpiece and the feed speed of the workpiece in the grinding direction, we can calculate load fluctuations due to changes in the shape of the workpiece in the grinding direction. This is absorbed by controlling the feed rate of the workpiece, making it possible to uniformly machine the workpiece to a constant height from the surface of the base material with a constant grinding load regardless of changes in the surface shape of the workpiece. It is something.

In addition, in order to finish the weld bead at a constant height from the surface of the base material of the workpiece, the base metal surface position and bead height position are detected by a seven-wheel sensor, and the feed system of the workpiece is adjusted so that the load on the grinding surface is constant. This makes it possible to control the same level of It gold in the upper and lower directions of the grinding object while controlling the speed.

FIG. 2 is an overall view of a bead finishing device devised for finishing a butt weld of a pipe 22.

This device has a fixed leg 24 that is directly attached to a pipe, a guide ring 23 that is attached to the guide ring in a manner that it is guided by the guide portion of the guide ring, and connected so that a rotary drive unit 27 and a grinding unit 26 can be attached. It consists of a connecting carriage 25.

The rotation drive unit 27 is configured to mesh with the teeth of the guide ring 23 and rotate in the circumferential direction integrally with the connecting carriage 25 and the grinding unit 26. FIG. 3 shows the control mechanism of the finishing device.

The grinding part is a grinding motor 37. Drive pulley 35. Contact wheel 33. When the σf grinding belt 34 is formed, the entire grinding group is raised and lowered by engaging with the trapezoidal screw 45 and the vertical lifting part 41, and the vertical lifting motor 42 drives the trapezoidal screw 45 through the gears 43 and 44. It is done. The position of the grinding surface of the abrasive belt is detected by the potentiometer 46 attached to the detector holder attached to the seat 52 of the connecting carriage to which the rotary drive unit 27 is attached, and the base metal surface position and weld bead position are detected. Then, the difference 57 between the two output voltages is compared with the output voltage 56 set by the height position setting unit 53, and the amplified output voltage 58 of the difference is used to control the grinding unit vertical lift motor 4.
This is done by driving 2. To correct the difference in the circumferential position of the bead height detection part and the grinding part, the bead height detection data is input into a microcomputer and the data at each circumferential position is made to match the data at the grinding part position. Circumferential position correction is being performed.

If there is a mismatch between the guide ring core and the pipe core due to irregularities on the bead surface or welding deformation of the pipe, load fluctuations will occur during rotary grinding in the circumferential direction of the pipe, and if the grinding motor is an air-driven motor, the load will be As a countermeasure to this problem, in the present invention, the rotation speed of the drive motor 37 is transmitted to the rotation speed detector via the gears 38 and 39, and the output voltage 59 and the grinding rotation speed setting section are 54
The output voltage 60 set in
The rotational speed of the motor 57 is controlled by the difference voltage 63 from the output voltage 62 set in step 5 so that the grinding motor reaches the number of rotations set in step 54, and as a result, the load is controlled and the This makes it possible to grind to a constant bead height.

According to this embodiment, the weld bead can be finished by automatic grinding to a constant height from the surface of the base material.

According to the present invention, the grinding load is controlled by controlling the head rotation speed in the circumferential direction, and the weld bead is fully automatically finished at a uniform height from the base metal surface while keeping the bead grinding amount constant per unit time. I can do that.

[Brief explanation of drawings]

FIG. 1 shows a method of controlling the rotational speed of a grinding motor to a constant value using a torque motor. FIG. 2 shows a situation in which the grinding head of the present invention is attached to the nob surface of the object to be ground. FIG. 3 shows the control method of the present invention. 22...Pipe, 23...Guide ring, 27...
・Rotary drive unit, 26...Grinding unit, 54・
...Grinding 7 no Figure r2 Figure

Claims (1)

[Claims] 1. A constant beet height grinding finishing method characterized by controlling the feed speed in the grinding direction to maintain a constant grinding load according to load fluctuations, and grinding while always keeping the grinding rotation speed constant.