JPS6218368Y2 - - Google Patents

Description

[Detailed description of the invention] When making a cut from the surface of a workpiece using a grindstone, the present invention allows the size of the cut from the surface of the workpiece to be set at a predetermined value, regardless of variations in the machining size in the previous step of machining the surface of the workpiece. The present invention provides an apparatus for controlling and processing the dimensions.

Some types of valves for the purpose of controlling the amount of fluid supplied have a cylinder with a cylindrical inner wall and a stepped shaft-shaped valve body inserted into the cylinder, and a part of the valve body has a cylinder with a cylindrical inner wall. There is a method in which a surface perpendicular to the diametrical direction of the cylinder is formed by cutting and grinding, and the flow rate is controlled by the distance between the inner wall of the cylinder and the surface in the diametrical direction. When machining this type of valve, it is necessary to accurately ensure the distance between the inner wall surface of the cylinder and the above-mentioned surface. Therefore, it is necessary to ensure that the distance between the inner wall surface of the cylinder and the above-mentioned surface is accurately ensured. This creates a need to accurately control the depth of cut from the surface of the surface. In such a case, dimensions cannot be controlled using a normal sizing device that controls the position of the grindstone head based on the distance from the axis of the valve body supported by the workpiece support device.

Based on the above facts, this invention provides a measurement reference surface near the grinding part of the workpiece, in which the position of the grindstone is controlled by the workpiece support device, and the grinding of the workpiece and the grinding wheel on the grindstone is carried out. The distance to the grinding surface is measured by a sizing device and the feeding device of the grinding wheel head is controlled. , a pair of inspection wheels having a circumferential surface having a smaller diameter than the outer diameter of the grinding wheel are provided in parallel with the grinding wheel, each having a stylus at its tip in association with a workpiece support device provided on a table above the bed; A measuring head is provided, and the measuring head brings the stylus of one measuring stylus into contact with the circumferential surface of the measuring wheel, and the stylus of the other measuring stylus is brought into contact with the stylus of the other measuring stylus on the table. While bringing the workpiece located on the workpiece support device into contact with a predetermined reference surface,
A measuring device is provided that includes a control circuit that generates an output signal corresponding to the relative movement amount of the pair of gauge heads, and the measuring device controls the grindstone drive device based on the output signal of the control circuit. , which controls the feed amount of the grindstone.

According to the present invention, the inspection device including the inspection wheel, the measurement head, and the control circuit outputs an output signal corresponding to the distance between the circumferential surface of the inspection wheel and the reference surface of the workpiece. The distance between the reference surface of the workpiece and the grinding surface of the grinding wheel can be measured, and when the output signal of the measuring device indicates the set value, the feeding of the grindstone head is stopped, and the distance between the reference surface of the workpiece and the grinding surface of the grinding wheel can be measured. The depth of cut can be controlled with high precision, and the influence of variations in the machining dimensions of the reference surface in the previous process can be eliminated.

FIG. 1 of the accompanying drawings shows an example of a workpiece W to be subjected to sizing cutting and grinding using the apparatus of the present invention. In the previous stage, the workpiece W has a flange portion 101,
The piston portion 102 and the base portion 103 are formed into a stepped shaft shape with a cylindrical surface having a larger diameter than the remaining portion.

Then, the piston portion 102 is attached to the workpiece W.
A flat portion 10 having a depth of l in the diametrical direction from the surface thereof.
6 is ground with a grindstone G, and the dimensional accuracy of the depth of the flat portion 106 requires extremely strict control. However, considering the variation in the diameter dimension of the piston portion 102 due to processing in the previous stage processing, it is not possible to control the cutting depth of the flat portion 106 with the central axis of the workpiece W as a reference. Therefore, it is necessary to take into account the variation in the diameter of the piston portion 102 and to strictly control the size of the cut from the circumferential surface of the piston portion 102.

FIG. 3 shows a top view of an embodiment of the present invention, in which the workpiece W is mounted on a tailstock 3 and a center holder 4, respectively, which are provided on a table 2 placed on a bed 1. It is rotatably supported by supported centers 5 and 6. A disc-shaped grindstone G is fixed to a rotary shaft 8 rotatably supported on a whetstone head 7, and a disc-shaped inspection wheel 9 with a slightly smaller diameter than the whetstone G is attached to the rotary shaft 8.
The grindstone 9 and the inspection wheel 9 are fixed concentrically and in parallel in the axial direction, and when the rotary shaft 8 is rotationally driven by the motor 10 via the pulley and belt, the grindstone 9 and the inspection wheel 9 are rotated integrally. .

The grindstone head 7 is made to move forward and backward toward the table 2 on the bed 1 by a well-known drive device (not shown), and is moved forward toward the table 2 while rotating the grindstone G by a motor 10. ,
When the grinding surface of the grinding wheel G has cut into the workpiece W to a predetermined size, the progress of the grinding wheel G is stopped by a signal from the measuring device consisting of the measuring wheel 9, the measuring head 22, and the control circuit. is being used.

A clamping device 11 is fixed to the table 2 on the opposite side of the grinding wheel head 7 with respect to the support centerline of the workpiece W by the centers 5 and 6, and locks the rotation of the workpiece W. The clamping device 11 includes a base 12 fixed on the table 2, a piston rod 15 having a piston 14 that is slidable within a cylinder 13 formed inside the base 12, and fixed to the top of the piston rod 15. A clamp arm 16 and a clamp arm 16 provided on a protrusion of the base body 12.
When pressure hydraulic fluid is introduced into one of the cylinder chambers partitioned by the piston 14 of the cylinder 13, one of the protrusions 105 on the base 103 of the workpiece W is The clamp arm 16 is gripped between the protrusion at the free end of the clamp arm 16 and the stopper 17, and the workpiece W supported by the centers 5 and 6 is prevented from rotating around the support center line;
When pressure hydraulic oil is introduced into the other cylinder chamber, the gripping state of the workpiece W is released.

A measuring head 22 is fixed to the table 2 via a support bracket 21 on the wheel head 7 side of the support center line of the workpiece W by the centers 5 and 6 of the table 2. The measuring head 22 is provided with a pair of probes 24, 24 each having a stylus 23, 23 formed at the tip thereof, as shown in FIG.
The control circuit shown in FIG. 5 incorporates a differential transformer whose core is moved in proportion to the amount of relative movement of the probes 24, 24, and the primary coil of the differential transformer is excited by an oscillator 25. An AC signal proportional to the displacement of the core is output from the secondary coil of the differential transformer to the positive input terminal of a differential amplifier 26.

The differential amplifier 26 has the oscillation signal of the oscillator 25, which is made low level by the resistance of the variable resistor 27, applied to its negative terminal, and divides the signal input applied to its positive terminal by the amount of the input signal of the negative terminal. The signal is output to the synchronous rectifier circuit 28. The synchronous rectifier circuit 28 is coupled to the oscillator 25;
The input signal from the differential amplifier 26 is converted into a DC signal and output to two voltage comparison circuits 29 and 30, and the output is displayed on a meter 31.

The voltage comparator circuit 29 compares the reference voltage with the voltage of the input signal, and when the difference reaches a predetermined value, generates a first-stage signal _S1 that commands the forward and slow movement of the grinding wheel head, and the voltage comparator circuit 30 compares the reference voltage and the voltage of the input signal, and when the difference becomes zero or a difference indicating a fixed size cut, a fixed size signal _S2 for stopping or retracting the grinding wheel head 7 is generated to control the grinding wheel head driving device.

In the figure, reference numeral 35 is a center ram that advances and retreats the center 5 of the tailstock 3, 36 is a cylinder that controls the advance and retreat of the center ram, 37 is a truing device that grinds the circumferential grinding surface of the grinding wheel G, and 38 is a drive thereof. 39 indicates a truing tool.

In the apparatus according to the embodiment of the present invention configured as described above, the workpiece W is placed on the table 2 and the psychological table 3
The table 2 is supported between the centers 5 and 6 of the center holding table 4, and its rotation is locked by the clamp device 11, and the grinding surface of the grinding wheel G is placed in contact with the piston portion 102 of the workpiece W. fix the position.

At this time, one of the measuring heads 2 of the measuring head 21
4 is the piston portion 1 which is the surface to be ground of the workpiece W.
02 and said piston portion 1
A reference surface is set at a place that has been subjected to a pre-stage process similar to that of 02, for example, on the circumferential surface of the base 103, and the stylus 23 of the measuring element 24 is brought into contact with the other measuring element 2.
The stylus 23 of No. 4 is brought into contact with the circumferential surface of the inspection wheel 9 fixed concentrically with the grindstone G. The peripheral surface of the base 103 of the workpiece W has been ground together with the piston portion 102 in the previous stage of machining.
Since the diameter variations of the base portion 103 and the piston portion 102 are approximately the same, it can be assumed that the diameter variations of the base portion 103 are the same as those of the piston portion 102. Further, if the circumferential surface of the flange portion 101 is subjected to a grinding process when the piston portion 102 is ground, the circumferential surface of the flange portion 101 can also be used as the reference surface. Furthermore, if the circumferential surface of the base 103 is ground simultaneously with the circumferential surface of the piston portion 102 by the same grindstone, the diameter of the base 103 can be considered to be the same as the diameter of the piston portion 102. When the diameters of the piston portion 102 and the reference surface are different, the difference in diameter can be controlled by adjusting the resistance value of the variable resistor 25 in the same way as when the diameters are the same.

In this way, the grinding wheel head 7 is advanced with the pair of measuring elements 24, 24 in contact with the reference surface of the workpiece W and the measuring surface of the circumferential surface of the measuring wheel 9, and the grinding surface of the circumferential surface of the grinding wheel G is When the distance between the piston surface 102 of the workpiece W and the piston surface 102 of the workpiece W reaches a predetermined distance, the control circuit generates a first-stage signal _S1 from the voltage comparison circuit 29 to control the drive device of the grindstone head to slow feed, and When the incision grinding process of the piston surface 102 by the G is started, and the signal generated by the relative movement of the pair of probes 24 and 24 becomes a signal indicating a cut of a predetermined size from the surface, the control circuit uses the voltage comparison circuit 30 to A sizing signal _S2 is generated to control the grindstone drive device to stop or move the grindstone head 7 backward.

When the grindstone G becomes worn due to repeated machining, the table 2 is moved to bring the truing device 37 to the rotation position of the grindstone G, and while rotating the grindstone G and the truing tool 39, the table 2 is adjusted to the width of the grinding surface of the grindstone G. When the grindstone G is reciprocated by a corresponding length, the grinding surface of the grindstone G is regenerated. In this case, since the diameter of the grinding wheel G is reduced by the result of truing, the resistance value of the variable resistor 27 is adjusted to send an oscillation signal at a lower level than before the grinding wheel G is regenerated to the negative input terminal of the differential amplifier 26. In addition, by making the positive input signal of the differential amplifier 26 into an output signal that is lowered by that amount, it is possible to absorb the measurement difference of the measuring device due to the decrease in the diameter of the grindstone G.

However, severe wear of the grinding wheel G may cause errors in the sizing device, so in the case of the present invention, the grinding wheel G
A grinding wheel (trade name: CBN) made of hard abrasive grains such as cubic boron nitride, which is less abrasive, is preferable as the material.
When using this seed grindstone, the truing tool is preferably a tool using diamond grains.

In the present invention, a workpiece support device is provided on a table above a bed to support a workpiece;
A grindstone head that is slidable on the bed toward the workpiece support device, a grindstone supported so as to be rotationally driven by the grindstone head, and a grindstone head for grinding the workpiece with the grindstone. In a grinding device comprising a grinding wheel head driving device that sends a grinding wheel head toward a workpiece, and an inspection device controlling the grinding wheel head driving device, the inspection device is arranged parallel to the grinding wheel in a concentric position on the grinding wheel head. A measuring wheel is provided and has a circumferential surface having a smaller diameter than the outer diameter of the grinding wheel, and one of a pair of probes each having a stylus at the tip is placed on the table to touch the circumferential surface of the measuring wheel. A measuring head disposed with a stylus in contact and the other stylus in contact with a predetermined reference surface of a workpiece supported by the workpiece support device, and an output signal corresponding to the relative movement amount of the measuring head. The inspection device is characterized in that it controls the grindstone drive device based on the output signal of the control circuit to control the feed amount of the grindstone. is supported by a workpiece support device on a table, and the stylus of one probe provided on the measuring head of the inspection device is brought into contact with a predetermined reference surface of the workpiece.
When the grinding wheel head is slid toward the workpiece while the stylus of the other probe is in contact with the front surface of the measuring wheel of the measuring device, which is installed parallel to and concentrically with the grinding wheel. , the pair of gauge heads move relative to each other in accordance with the movement of the grindstone head, so that the control circuit generates an output signal corresponding to the amount of relative movement of the gauge heads. The output signal of this inspection device is generated when the probes of a pair of probes installed in the measurement head come into contact with the front surface of the inspection wheel and the reference surface of the workpiece supported by the workpiece support device. This signal corresponds to the distance between the tips of the needles and indicates the distance between the front surface of the inspection wheel and the reference surface of the workpiece, but the inspection wheel is installed coaxially with the grinding wheel. Since the radius difference between the two is known, and the workpiece surface and reference surface are known in terms of the dimensions of the workpiece, the signal is transmitted between the grinding surface of the grindstone and the surface of the workpiece portion. Since it can be converted into a distance, it can be used as a sizing signal to measure the amount of cut into the workpiece by the grindstone, and the control device can be controlled based on the signal from the measurement device to feed the grindstone by the drive device. The amount can be precisely controlled.
Therefore, even if there are dimensional variations in the machining of the part of the workpiece that requires sizing cutting and grinding in the previous stage of machining, the previous stage of machining can be performed at the same time as the part that requires sizing cutting and grinding. If the circumferential surface of the part is used as a reference surface and processed according to the present invention, almost no variation will occur.

In addition, in the present invention, if the diameter of the workpiece part and the diameter of the reference surface are different, or if the diameter of the grinding wheel decreases as a result of true ringing of the grinding wheel, based on the signal generated by the inspection device, By providing a control device that controls the drive device with a correction means that adds a correction corresponding to the diameter difference to the signal, cutting accuracy can be maintained.

[Brief explanation of the drawing]

FIG. 1 is a front view of an example of a workpiece to be cut by the apparatus of the present invention, and FIG. 2 is a sectional view taken along the line shown in FIG. 1. 3 to 5 show an embodiment of the device of the present invention, and FIG. 3 is a top view thereof;
Figure 4 is a partial sectional view taken along the line of Figure 3;
The figure is a circuit diagram of the main parts of the inspection and control device. In the figure, W is the workpiece, G is the grindstone, 1 is the bed,
2 is a table, 7 is a grindstone head, 9 is an inspection wheel,
11 is a clamp device, 22 is a measurement head, 23 is a stylus, 24 is a measurement head, 25 is an oscillator, 26 is a differential amplifier, 27 is a variable resistor, 28 is a synchronous rectifier circuit, 29 and 30 are voltage comparison circuits, S ₁ indicates a first stage signal, and S ₂ indicates a synchronization signal.

Claims (1)

[Claims for Utility Model Registration] A workpiece support device provided on a table on a bed to support a workpiece; a grindstone head slidable on the bed toward the workpiece support device; A grindstone supported so as to be rotationally driven by a grindstone, a grindstone drive device that sends the grindstone toward the workpiece in order to grind the workpiece with the grindstone, and an inspection that controls the grindstone drive device. and a grinding device, the inspection device comprising: an inspection wheel that is provided on the grindstone table in parallel and concentrically with the grindstone, and has a circumferential surface with a smaller diameter than the outer diameter of the grindstone; and the table. One of a pair of probes provided on the top and each having a stylus at the tip is brought into contact with the circumferential surface of the inspection wheel, and the other is placed on the workpiece surface of the workpiece supported by the workpiece support device. a measuring head disposed with its stylus in contact with a predetermined reference surface of a workpiece whose dimensions in relation to the stylus are known; and a control circuit that generates an output signal corresponding to the relative movement of the stylus. A sizing cutting grinding device, characterized in that the measuring device controls the grindstone drive device based on the output signal of the control circuit to control the amount of feed of the grindstone.