JPH06278020A - Method of grinding - Google Patents

Abstract

PURPOSE:To grind a corner portion to size a while ensuring the dimensional accuracy of a cylindrical portion by first grinding a position of the cylindrical portion which is measured by a measuring instrument, then resetting and correcting a coordinate system in the direction perpendicular to the axis of a grinding wheel, and then grinding the cylindrical portion and the corner portion. CONSTITUTION:A grinding machine 10, having a measuring instrument 16 for measuring the diameter of the cylindrical portion (a) of workpiece W and a grinding wheel G movable relative thereto in the direction Z parallel to the axis of the workpiece and in the direction (x) perpendicular to the axis, is used to grind the cylindrical portion (a) and that portion (b) of workpiece W which adjoins to the cylindrical portion. In that case, part of the portion (b) is measured using the measuring instrument 16 and is then plunge cut, and when the measuring instrument 16 outputs a signal indicating that the diameter of the cylindrical portion (a) has reached a desired value, a coordinate system in the direction (z) perpendicular to the axis of workpiece is reset according to the signal output from the measuring instrument 16, and the cylindrical portion (a) and corner portion (b) of workpiece W are continuously ground according to the coordinate system reset.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention grinds a cylindrical portion of a workpiece and a corner portion adjacent to the cylindrical portion by using a grinder capable of relative movement in a direction parallel to a workpiece axis and a direction intersecting the axis. The present invention relates to a grinding method for processing.

[0002]

2. Description of the Related Art Conventionally, as a method for grinding a cylindrical work W at a high speed, there is one shown in FIG. This uses a grindstone G provided with a straight portion Gs parallel to the rotation axis of the workpiece W and a tapered portion Gt inclined with respect to the rotation axis of the workpiece W. First, the grindstone G is positioned at one end of the workpiece W. Then, while rotating the workpiece W and the grindstone G respectively,
The grindstone G is moved closer to the workpiece W. That is, the workpiece W is moved in a direction orthogonal to the rotation axis, and rough grinding,
Fine grinding and fine grinding are sequentially performed (hereinafter, a method of performing grinding by relatively moving the workpiece W and the grindstone G in a direction orthogonal to the rotation axis of the workpiece W is referred to as plunge grinding). , Only one end of the workpiece W is machined to a desired finishing dimension. Thereafter, the entire workpiece W is ground while moving the workpiece W along the rotation axis direction of the workpiece W to the other end of the workpiece W (hereinafter, in the rotation axis direction of the workpiece W as described above). A method of performing a grinding process by relatively moving the workpiece W and the grindstone G along this is called traverse grinding). In such a grinding method, during the traverse grinding, rough grinding is performed by the taper portion Gt of the grindstone G, and then the straight portion Gs.
Since the finish grinding can be performed by, the entire workpiece W can be ground by one traverse grinding.

Then, as shown in FIG. 5, when the cylindrical portion a of the workpiece W is machined by the above-mentioned high-speed grinding and the arc-shaped corner b and the end face c adjacent to the cylindrical portion a are ground. The end face c, the corner b, and the cylindrical portion a were ground in this order. Among these, for the grinding of the end face c and the corner b, the cutting amount in the X-axis direction and the feed amount in the Z-axis direction are controlled by the coordinates of the grindstone G on the grinder (hereinafter referred to as machine coordinates),
In order to attach importance to the dimensional accuracy of the cylindrical portion a in grinding the cylindrical portion a, the grindstone G is controlled by the coordinates of the workpiece when the workpiece W is actually machined (hereinafter referred to as the workpiece coordinates). It was That is, when the sizing device 16 detects that the diameter of the left end of the cylindrical portion a has reached the target dimension, and the detection signal is output, as in the plunge grinding in the above-described high speed grinding,
The cutting in the X-axis direction is stopped, and the traverse grinding is performed only by feeding in the Z-axis direction to grind the cylindrical portion.

[0004]

In the grinding process, the machine coordinate of the grinder and the work coordinate are caused by the reduction of the diameter of the grindstone due to the abrasion of the grindstone G, the eccentricity due to the workpiece support and the deflection due to the rotation of the workpiece W. There is a gap between and. Therefore, when the grinding process is performed by the above-mentioned conventional technique, the following states occur. That is, as shown in FIG. 6 [A], the cutting in the X-axis direction of the grindstone G is cut by α larger than the actual size, and as a result, the sizing device is not completely formed in the arc shape of the corner b. A state in which 16 detection signals are output and traverse grinding of the cylindrical portion a is started.
On the contrary, as shown in FIG. 6B, after the X-axis cut on the grinding machine is cut smaller than the actual size by β, as a result, the arcuate shape of the corner b is completely formed. Still, the state in which the step portion e is formed due to the traverse grinding of the cylindrical portion a after the cutting in the X-axis direction by the plunge grinding occurs. Due to the two grinding states described above, there is a problem that the corner portion b having the target size cannot be formed.

Therefore, it is an object of the present invention to provide a grinding method capable of processing a corner portion a having an accurate shape according to a target dimension in order to solve the above-mentioned problems.

[0006]

Plunge grinding is performed while measuring a part of a cylindrical portion with a measuring device, and when the measuring device outputs a signal indicating that the diameter of the cylindrical portion has reached a target value. , The coordinate system in the direction intersecting the workpiece axis of the grindstone is reset based on the output signal of the measuring device, and the cylindrical portion and the corner of the workpiece are continuously arranged based on the reset coordinate system. It consisted of grinding.

[0007]

First, while a part of the cylindrical portion of the workpiece is measured by the measuring device, plunge grinding is performed to a target value in a direction intersecting the axis of the workpiece. When it is detected that the workpiece cylindrical portion has reached the target value by the measuring device, the coordinate system in the direction intersecting the workpiece axis of the grindstone is reset based on the output signal of the measuring device, and the grindstone and the measuring device are set. fall back.

Then, the end surface, the corner portion and the cylindrical portion of the workpiece are ground by one continuous grinding by the reset coordinate system.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of a grinder that grinds a workpiece having arc-shaped corners by using the grinding method of the present invention. 10 is a grinder main body, and a bed 12 is provided with a table 12 and a grindstone base 13. The table 12 is driven by a table-driving servomotor 27 provided on the bed 11 to move the Z-axis by a feed screw mechanism (not shown).
The wheel head 13 can be moved in the axial direction (left and right direction in the drawing), and the wheel head 13 is driven by a wheel head driving device 26 provided on the bed 11, and an X axis orthogonal to the Z axis by a feed screw mechanism (not shown). It can be moved in any direction (up and down in the drawing).

A headstock 14 and a tailstock 15 are provided on the table 12, and both ends of the work W are supported by the center. A spindle driving servomotor 28 is fixed to the spindle stock 14, and the workpiece W is rotated by driving the spindle driving servomotor 28. The grindstone base 13 is provided with a grindstone G rotated by a motor for rotating a grindstone (not shown). The grindstone G is a disk-shaped grindstone core provided with a grindstone layer on the outer periphery thereof, and this grindstone layer is formed by bonding CBN abrasive grains with vitrified bonds.
A straight portion Gs parallel to the rotation axis of the workpiece W and a taper portion Gt inclined with respect to the rotation axis of the workpiece W are provided on the outer periphery of the grindstone G. As shown in FIG. 7, the taper portion Gt has a length H in the radial direction of the grindstone G of the taper portion Gt.
Is set to be longer than the distance h from the outer diameter at the start of machining of the workpiece W to the finished diameter of the workpiece.

Numeral 16 is a sizing device, which is a table 1
The measuring head 18 is mounted on the bracket 17 attached to the
Is supported so that it can move forward and backward, and the diameter of the cylindrical portion of the workpiece W is measured. A pair of contacts 19 is displaceably supported on the measurement head 18, and a signal corresponding to the displacement amount of the contacts 19 is output by a displacement detector provided in the measurement head 18 and input to an amplifier 20. . Amplifier 20
Compares the preset setting value with the input signal, and outputs a sizing signal to the numerical control device 21 described later at the coincidence point,
The feed forward end position of the grindstone base 13 is controlled.

A grinding wheel head drive circuit 36, a table driving circuit 37, and a spindle drive circuit 38 are connected to the numerical control device 21.
6. The drive of the table driving servo motor 27 and the spindle driving servo motor 28 is controlled. Next, a grinding process for processing an arc-shaped corner portion by using the grinding method according to the present invention will be described with reference to FIGS. 2 and 3. FIG. 2 is a diagram showing a first grinding process in which the cylindrical portion a of the work W is plunge-ground while performing a constant measurement, and FIG. 3 is a second grinding process in which the work is actually ground to a target size.
It is the figure which showed grinding processing.

First, as shown in FIG. 2, the measurement position of the sizing device 16 in the cylindrical portion a of the workpiece W is first ground by plunge grinding. The sizing device 16 performs in-process measurement that constantly measures during plunge machining.
When grinding is performed up to a set value described later, a sizing signal is output to stop the cutting of the grindstone G. Here, the set value is set to a value larger than the actual finished dimension D (the two-dot chain line in the drawing) by a minute amount Δd.

When the sizing signal is output and the cutting of the grindstone G is stopped, the coordinate system in the X-axis direction of the grindstone G at this position is reset and the grindstone G is retracted. Then, since the machine coordinate system of the grindstone G and the workpiece coordinate system which is the coordinate system of the shape of the workpiece match, as shown in FIG. 3, the section P1- of the end face c along the machining shape of the workpiece W is obtained. Plunge grinding P2,
A second grinding process is performed in which a section P2-P3 of the corner portion b is arc-ground and a section P3 and subsequent portions of the cylindrical portion a are traverse ground.

Next, FIG. 4 will be described in detail with reference to the flow chart showing the flow of the grinding process of this embodiment. In step 100, the amplifier 20 is operated by the numerical controller 21.
Set the diameter value (setting value) of the workpiece W when outputting the sizing signal. This value is set so that the finishing dimension D of the cylindrical portion a of the workpiece W is set to a large value by a small amount Δd so as not to affect the machined surface during the main grinding.

In step 101, the sizing device 16 is moved forward, and while the in-situ measurement is performed by the sizing device 16, the grindstone G is cut until the diameter of the cylindrical portion a of the workpiece W becomes D + Δd. The cutting of the grindstone G is actually given a value of D + Δd−Δv obtained by subtracting the overcount value Δv in consideration of the deviation between the machine coordinate and the workpiece coordinate, and the grindstone G always reaches the set value. It is like this.

At step 102, the coordinate system of the grindstone G is reset. The resetting of the coordinate system here means that the machine coordinate is corrected by obtaining the amount of deviation between the machine coordinate and the workpiece coordinate, and the value of a counter (not shown) that counts the current position of the wheel head 13 And the value of the sizing device 16 are matched (actually, the machine coordinate is newly set by the G code (G92) of the NC program to match the machine coordinate and the workpiece coordinate).

In step 103, the grindstone G (specifically, the grindstone base 13) is retracted, and in step 104, the sizing device 16 (specifically, the measuring head 18) is retracted. In step 105, as shown in FIG. 3, a second grinding process for actually grinding the workpiece W to a target dimension is performed. The end face c is plunge-ground at 105a, and then the corner b is arc-ground at 105b. Finally, the cylindrical portion a is traversed to finish the grinding process. In this case, since the machine coordinates are reset in step 102, the position of the grindstone G in the machine coordinates and the size of the workpiece match, and the arc grinding of the corner b is started from the grinding end point P2 of the end surface c. , The end point P3 for grinding the corner b
The traverse grinding of the cylindrical portion a is started further, and the corner portion b having the target dimension is formed.

As described above, when the end face c, the corner b and the cylindrical part a of the workpiece W are machined, the end face c and the corner b are ground as in the conventional method, and then the sizing device 16 is used to form a cylinder. Instead of starting the grinding of the part a, first, the measuring position of the cylindrical part a by the sizing device 16 is ground by an appropriate amount, and the coordinates of the wheel head are corrected correctly, and then the end face c, the corner b and the cylindrical part a are corrected. Since the machining is performed, there is an effect that the accuracy of the cylindrical portion a can be secured and the corner portion b can be ground according to the target dimension.

In this embodiment, after the machine coordinates of the wheel head are reset, the end face c, the corner b, and the cylindrical part a are ground in this order, but the cylindrical part a and the corner b are processed. The same effect can be obtained by performing processing in the order of the end face c. Further, in the present embodiment, the formation of the arcuate corner portion has been described, but the taper-shaped corner portion can be similarly ground.

[0021]

As described above, in the processing of the cylindrical portion and the corner portion of the workpiece according to the present invention, the grinding of the cylindrical portion is started using the measuring device after the corner portion is ground as in the conventional case. Instead, first grind the measurement position of the cylindrical part with the measuring device by an appropriate amount, reset the coordinate system in the direction intersecting the grindstone axis and correct it correctly, and then grind the cylindrical part and the corner Therefore, there is an effect that the accuracy of the cylindrical portion can be ensured and the corner portion can be ground according to the target dimension.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a grinding machine showing an embodiment of the present invention.

FIG. 2 is a diagram showing a first grinding process.

FIG. 3 is a diagram showing a second grinding process.

FIG. 4 is a flowchart showing a grinding process.

FIG. 5 is a diagram showing a conventional grinding process.

FIG. 6 is a diagram showing a conventional grinding result.

FIG. 7 is a diagram illustrating a conventional grinding process.

[Explanation of symbols]

 10 Grinder 12 Table 13 Tailstock 16 Sizing Device 20 Amplifier 21 Numerical Control Device G Grindstone L Work Axis W Work

Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location B24B 49/10 9135-3C G05B 19/403 F 9064-3H (72) Inventor Toshihiro Tsutsui Asahi-cho, Kariya city, Aichi prefecture 1-1 chome Toyota Koki Co., Ltd.

Claims (1)

[Claims] 1. A grinding machine having a measuring device for measuring a diameter of a cylindrical portion of a workpiece and having a grindstone capable of relative movement in a direction parallel to the workpiece axis and a direction intersecting the axis.
In a grinding method for grinding a cylindrical portion of a workpiece and a corner adjacent to the cylindrical portion, plunge grinding is performed while measuring a part of the cylindrical portion with the measuring device, and the diameter of the cylindrical portion is measured by the measuring device. When the signal indicating that the target value has been reached is output, the coordinate system in the direction intersecting the workpiece axis of the grindstone is reset based on the output signal of the measuring device, and the reset coordinate system is set. The grinding method is characterized in that the cylindrical portion and the corner portion of the workpiece are continuously ground based on the above.