JPH0197809A - Detector of surface defect - Google Patents

Abstract

PURPOSE:To dispense with the rotation of a work piece and thereby to enable the execution of accurate and rapid inspection, by constructing an inspecting element of a fixed part connected to a signal line and a rotatable detecting part separate from the fixed part and by effecting the transmission of information between them by means of rays of light. CONSTITUTION:An inspecting element is constructed of a fixed part connected to a signal line and formed of a case 17, and of a rotatable detecting part formed of a case 18 of a movable part, and the transmission of information between them is effected by means of rays of light. A ray of light of a laser diode 10 is projected onto the wall surface of a tubular hole of a work piece 1 through a collimate lens 11, a beam splitter 12, a prism 13 and an objective lens 14, and a reflected ray of light goes back along the same route, passes through the condenser lens 14 and is sensed by a photodiode 16, in which a change in the quantity of light is analyzed and the state of the surface is measured. Accordingly, it is not necessary to rotate the work piece 1, and the measurement can be executed accurately and rapidly without restriction by the number of rotations.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a surface defect detector, and in particular detects holes, scratches, etc. on the inner wall surface of a hole such as a cylindrical hole in an engine cylinder block. The present invention relates to a detector suitable for inspecting surface defects or roughness on an inner wall surface.

(Prior Art) The present invention, for example, emits light of a certain intensity from a projector, receives the light reflected from the object to be measured, and analyzes changes in the amount of received light to determine the surface barb state. Targeting vessels.

Such a detector generally has a detection section including a light emitter, a light receiver, etc., and a signal line connected to the detection section.

(Problems to be Solved by the Invention) When detecting cavities, scratches, etc. on the inner wall surface of the cylinder using this detector, the method shown in FIGS. 2 and 3 has conventionally been used.

In the case of Fig. 2, the detection unit 3 is placed in the cylinder chamber 2 of the workpiece 1 to be measured, and after facing the wall surface of the cylinder chamber, the workpiece 1
The entire wall surface is explored by rotating the wall about its central axis and sliding it up and down at the same time. In this method, it is necessary to rotate the workpiece, but it is surprisingly difficult to rotate a large non-circular workpiece with high precision and at a relatively high speed.

On the other hand, in the case of Fig. 3, the workpiece 1 is kept stationary and the detection part 3 is rotated and slid upward or downward, and the problem as in the case of Fig. 2 does not occur. On the other hand, since the detection section 3 is rotated, the signal line 4 is twisted, which inevitably limits the number of rotations of the detection section 3 and limits the measurement target.

An object of the present invention is to provide a detector that requires rotating a workpiece and is not limited by the number of rotations of the detection section.

(Means for Solving the Problems) The present invention configures the detection unit by dividing it into a fixed part connected to the signal line and a probe part rotatable with respect to the fixed part,
The above purpose is achieved by transmitting information between the two using light beams.

(Embodiment) In the embodiment of the present invention shown in FIG. 1, lO in the figure indicates a laser diode (semiconductor laser) that emits a laser beam, and the laser beam emitted from this diode is passed through an optical system, that is, a collimating lens. 11, Beam splitter 1
2. Workpiece 1 via prism 13 and objective lens 14
The light is projected onto the wall 2 of the cylinder chamber, and the light reflected from the wall is received by the objective lens 14, and then the prism! 3. Beam splitter 12 and condensing lens! 5 and enters the photodiode I6. This change in the amount of received light is analyzed by a rear analysis device, and the presence or absence of cavities, scratches, etc. on the wall of the cylinder chamber is determined.

The above laser diode 10 and photodiode 1B
is connected to a signal line (not shown) in a known manner. Both of these diodes to and is, together with the collimating lens 111, the beam splitter 12, and the condensing lens 15, are attached to the fixed part case I7 or a member (not shown) integrated with the case.

On the other hand, the prism 13 and objective lens 14 are movable parts! It is installed in 8. Case 18 is a prism! 3 and a lens barrel 18a holding the objective lens 14; The support part 18b consists of a support part 18b.
b is rotatably supported by the fixed part case 17 by a bearing I9.

A motor 20 is provided to rotate the case 18 about the axis of the support part 18b, and this motor is connected to a rotor coil 20b attached to the inner circumferential surface of the edge of the rotor 20a in a horizontal position, and a rotor coil 20b attached to the fixed part case 17. The rotor 20a is mounted on the support portion tab of the case 18 by a suitable mounting member 21.

As is clear from the above, among the members constituting the detection section,
Laser diode 10, collimating lens 11, beam splitter 12, condensing lens 15, photodiode 1
6 forms a fixed part and is also a prism! 3. The objective lens I4 forms a rotatable exploration part with respect to the fixed part, and information is transmitted between the two by light rays.

During operation, after the rotational axis of the probe section is placed on the same line as the axis of the cylinder chamber 2 of the workpiece 1, the probe section is rotated by the motor 20, and at the same time, the entire detection section is rotated downward or downward by appropriate means. It is slid upward. Of course, during this operation, a laser beam is emitted from the laser diode 10, so that the wall surface of the cylinder chamber 2 is thoroughly explored.

In addition, the objective lens of the above-mentioned lens barrel 18a! If the holding part 4 is bent downward at a right angle and a prism is placed at the bent part, it is possible to inspect flaws on a flat surface such as the bottom of the cylinder chamber 2 using the processing procedure of a milling machine.

(Effects) As described above, according to the present invention, there is no need to rotate the workpiece, and the exploration part can be rotated by the required number of rotations at a desired speed without being restricted by the signal line. It is possible to accurately and quickly perform an external appearance inspection of the cylinder chamber side wall of a difficult and large workpiece over a desired range, regardless of the depth of the cylinder chamber.

[Brief explanation of the drawing]

FIG. 1 is a schematic central longitudinal sectional view of a detector according to the present invention, FIG. 2 is a schematic diagram showing a conventional detection method, and FIG. 3 is a schematic diagram showing another conventional detection method. IO...Laser diode (semiconductor laser), 11.
...Collimating lens! 2...beam splitter,
13... Prism, +4... Objective lens, 15...
・Condenser lens, +6...Photodiode, 17...
・Fixed part case, 18...Movable part case, 20...
motor. Representative Patent Attorney 1) Osamu Umi Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] In a surface defect detector that irradiates a workpiece surface with a light beam and determines surface defects based on changes in the amount of reflected light, a detection unit that is connected to other parts by a signal line detects a member that is connected to the signal line. It consists of a fixed part that has a fixed part, and a probe part that has only members that are not related to the signal line and is rotatable with respect to the fixed part, so that information transmission between the fixed part and the probe part is A surface defect detector characterized in that it is performed using a light beam.