JPH0757466B2 - Grinding machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a device for grinding a workpiece by adjusting a facing distance between rotating shafts facing each other.

[Prior Art] Conventionally, machining having a feed mechanism that attaches a grindstone to one of the opposing rotary shafts and a workpiece at the end of the other rotary shaft, and moves one of the rotary shafts in the direction of the opposing shaft. In the equipment, the grinding start position of the workpiece is visually confirmed, the dimensions of the workpiece measured in advance are taken into consideration, and the processing dimension is determined by calculation from the workpiece mounting surface, or the grinding stone and the workpiece are As a means for automating the detection of the front and back surfaces (front side of the work mounting board) of the feeding mechanism, a position detector such as a touch switch, a gap detection sensor or a load cell is provided in opposition to the control rod tip of the feeding mechanism. The position was set. (See, for example, Japanese Patent Application No. 63-108555.) [Problems to be Solved by the Invention] A signal sent from a linear scale reading head mounted on a moving plate, indicating the position at which processing is started in a conventional grinding apparatus of this kind. The change state of is detected and set, and
Durability in the grinding work environment by detecting the contact position between the grindstone and the workpiece mounting board, that is, the back surface position of the workpiece, and calculating and setting the desired finished dimension of the workpiece by the same means. It also aims to provide a highly accurate automatic sizing function without using a position ejector with inferior resolution.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a control rod that moves forward and backward in the left and right directions by the rotation of a feed screw shaft connected to a servo motor in a guide hole formed in a fixed base. A movable base urged toward the control rod so as to be slidable in the left-right direction so as to be opposed to the tip of the control rod, and a bearing portion on the fixed base and a bearing portion on the movable base. In addition, the respective rotary shafts linked to the motors are supported in parallel with the control rod, and a grindstone is attached to the inner end of the rotary shaft on the fixed base, and a work mounting plate is attached to the inner end of the rotary shaft on the movable base. By installing a linear scale on the moving platen facing each other and sending a signal from the linear scale reading head on the base corresponding to this to the pulse width detector to detect the change state of the signal. , The contact position between the grindstone and the workpiece and the workpiece The control means for detecting the contact position with the front surface of the mounting board is added.

[Operation] In the processing by the grinding apparatus configured as described above, first, when the moving platen is sent in the direction of the grindstone rotating shaft without driving the grindstone rotating shaft and the workpiece rotating shaft, a pulse corresponding to the rapid feed speed is generated. A signal is transmitted from the linear scale reading head, but when the front surface of the workpiece mounting board comes into contact with the front end surface of the grindstone, the signal from the reading head changes significantly from the pulse waveform in the fast-forwarding state so far. Or, since it becomes a non-transmission state, this changing point (point corresponding to a in FIG. 3 of the drawing) is detected by the pulse width detector, and this is made to correspond to the measured value of the linear scale, and the electronic control circuit ( CPU
Etc.).

Next, after moving the moving board back and fixing the work piece to the mounting board,
If the front surface of the grindstone and the workpiece are brought into contact with each other by advancing the movable plate again, the grinding start point is stored in the electronic control circuit by the same detection action as described above.

Therefore, if you set the desired finished size of the work piece whose thickness has been measured in advance to the constant size setting device connected to the electronic control circuit, the electronic control circuit calculates the scraping amount of the work piece,
Memorize the depth of cut and cope with automatic sizing.

[Embodiment] An embodiment of the present invention will be described with reference to the drawings. In FIG. Rotation axis 6 of object 5
Is equipped with a mounting board 7 for the workpiece 5 at its end, and a guide 9 and 9'engaged with a rail 8 on the base 2 allows the shaft to be mounted on a movable plate 10 which is slidable in the direction of the rotary shaft 1. It is supported.

The spring 11 connects the rear end of the movable platen 10 and a proper place on the base 2 which is spaced apart to give the movable platen 10 a movable force in the direction of the fixed base 3. The moving force can be substituted by other methods such as a hydraulic / pneumatic cylinder or a weight.

Reference numeral 12 denotes a control rod which has a rear end portion screwed into a feed screw shaft 14 connected to a servo motor 13 and which is non-rotatably fitted in a guide hole 15, and the front end portion thereof is in contact with the movable platen 10.

16 is a linear scale mounted on the moving board 10 and is a base 2
The signal from the reading head 17 engaged with the side is sent to the digital display 18, and is also input to the electronic control circuit that controls the drive of the servo motor 13 via the pulse width detector 19 that detects the change in the signal waveform. It is like that.

Reference numeral 20 is a constant size setting device for program-inputting the finished size of the workpiece 5, and this operation causes the display 21 to automatically display the machining depth of the grindstone 4.

Since the present invention is configured as described above, when the automatic start command of the apparatus is issued in a state where the grindstone 4 and the workpiece 5 shown in FIG.
And the rotary shaft 6 of the workpiece 5 start to rotate in opposite directions by a drive motor (not shown), and the servo motor 13
Driven by the high speed drive, the feed screw shaft 14 rotates and the control rod 12
Moves backward (moves to the left side of the drawing) and follows this to the moving board
10 moves forward fast by spring 11.

When the workpiece 5 moves to a position of 2 to 3 μm just before the workpiece 5 comes into contact with the grindstone 4 due to the forward movement of the movable platen 10, this position is stored in correspondence with the measured value of the linear scale 16 and the servo motor 13 from the electronic control circuit is stored. The rotation speed command to is automatically switched to the minute feed speed for grinding, which is set in advance by the material and shape of the workpiece.

Therefore, as the feed screw shaft 14 rotates, the control rod 12 retreats at a slight speed, and the moving plate 10 follows this and moves forward at an appropriate speed while being restricted by the movement of the control rod 12 by the spring 11. Grinding work adapted to is progressing.

Further, the signal from the reading head 17 of the linear scale 16 is sent to the digital display 18 so that the feed state of the workpiece 5 can be always read, so that the cutting feed rate command of the control rod 12 causes the workpiece 5 to be machined. It is possible to read whether or not it is appropriate for the conditions, and because the finished dimensions of the workpiece 5 are input in advance to the sizing setter 20, the reading head
Grinding is continued until the set value on the linear scale 16 corresponding to this designated position is detected, and normal and active grinding work that does not overload the work 5 is performed in a desired size. Continue until 5 is finished.

Further, in the precision grinding process, at the completion point of the cutting feed, the feed of the workpiece 5 is stopped and only the contact machining with the grindstone 4 is performed, so that the so-called spark out time is provided, so that the ground surface of the workpiece 5 is The roughness is dramatically improved, but this work can be easily incorporated into the grinding control.

EFFECTS OF THE INVENTION Since the present invention is configured as described above, the change in the signal from the linear scale reading head is detected by the pulse width detector so that the grindstone and the workpiece mounting board can be contacted in advance. The contact position and the contact position between the grindstone and the front surface of the workpiece are stored in the electronic control circuit as the set value on the linear scale, and the desired size of the product is program-input to the sizing setter to automatically It is possible to efficiently manufacture a product with a good finished surface by performing a basic grinding work, that is, rapid feed → grinding at an appropriate feed speed → spark out and a quick return part cycle.

Also, the conventional touch switch used to detect the set points on the grinding wheel and the front and back of the workpiece,
The gap detection sensor or load cell has a short service life and a low position setting accuracy in the working environment where the grinding liquid is splashed, but by replacing it with the linear scale mechanism, high resolution and long stable operation can be obtained. In addition to the simplification of the mechanical measuring unit, it is effective in improving the processing accuracy and reducing the processing cost, and the maintenance of the device itself is easy.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of the apparatus according to the present invention, FIG. 2 is a partially cutaway front view showing a state where a grindstone and a workpiece are in contact, and FIG. 3 is a reading of a linear scale. FIG. 4 is a block circuit diagram showing a main part of an electronic circuit which detects a signal change, and FIG. 4 is a graph showing a change part of a signal waveform transmitted from the head. 1 ... Grinding wheel rotation axis. 3 ... Fixed stand. 4 ... Grinding stone. 5: Processed product. 6 ... Workpiece rotation axis. 7 ... Workpiece mounting board. 10 ... Moving board. 12 ... Control rod. 13 ... Servo motor. 14 ... Feed screw shaft. 16 …… Linear scale. 17 ... Read head.

Claims (1)

[Claims] 1. A control rod that advances and retreats in the left-right direction by rotation of a feed screw shaft connected to a servomotor is fitted in a guide hole formed in a fixed base, and the control rod is opposed to the tip of the control rod. A movable base urged in the direction is provided slidably in the left and right directions, and the respective rotary shafts linked to the motor are parallel to the control rod in the bearing portion on the fixed base and the bearing portion on the movable base. Support, and a grindstone on the inner end of the rotary shaft on the fixed base,
At the inner end of the rotary shaft on the moving table, mounting plates for the workpieces are provided to face each other, and a linear scale is mounted on the moving plate.
Corresponding to this, the signal from the linear scale reading head on the base is sent to the pulse width detector, and by detecting the change state of the signal, the contact position between the grindstone and the workpiece and the front surface of the workpiece mounting board are detected. A grinding apparatus having a control means for detecting the contact position of the grinding machine.