JP2602965B2 - Automatic cylindrical grinding machine - Google Patents

Description

Description: Object of the Invention (Industrial application field) The present invention relates to an automatic cylindrical grinding device, and more particularly to an automatic cylindrical grinding device capable of precisely grinding an elongated cylindrical workpiece.

(Prior art) In order to machine an elongated cylindrical workpiece with high precision, an axis connecting a headstock and a tailstock that rotatably supports both ends of the cylindrical workpiece, and a moving axis of a grindstone or a cylindrical workpiece. It is necessary to adjust the parallelism. In addition, in order to prevent bending in the middle part of the cylindrical workpiece and prevent chatter vibration and the like, a steady rest device having a pawl touching the cylindrical workpiece is disposed at a position facing the grindstone table. .

Conventionally, such adjustment of the degree of parallelism and adjustment of the pawl contact of the steady rest device have been performed manually, but in recent years, automation of the work rest has been promoted due to a demand for automation of the grinding device. For example, a grinder equipped with a sizing device that measures the processing diameter of a cylindrical workpiece and a rest device that can detect that the claw of the steady rest device comes into contact with the cylindrical workpiece (Japanese
No. 62-5575) has been proposed.

In the above-described conventional grinding machine with a rest device, the sizing device detects that the claw portion of the steady rest device has come into contact with the cylindrical workpiece, thereby preventing a poor engagement of the rest device and a necessary pushing of the rest device. Quantity can be secured.

(Problems to be Solved by the Invention) When the cylindrical workpiece is elongated, the vicinity of the central portion is largely bent due to the pressing of the claw portion, or the center hole of the cylindrical workpiece is poorly engaged with the centers of the headstock and the tailstock. For example, the axis of the cylindrical workpiece may not be parallel to the moving axis of the grindstone or the cylindrical workpiece. In such a case, according to the above-mentioned conventional grinding machine, the diameter near the center of the cylindrical workpiece after grinding becomes small, or the difference in diameter between both ends becomes large. The problem that the maximum difference in the diameter of the workpiece in the axial direction) does not fall within the allowable value and the machining accuracy is reduced cannot be solved.

Further, when the cylindrical workpiece is elongated, if the claw portion of the steady rest device is not securely in contact with the cylindrical workpiece, grinding chatter vibration occurs during grinding, which may adversely affect the ground surface. On the other hand, when the pressing force of the claw portion is increased, the cylindrical workpiece is easily bent, which causes a problem that machining accuracy is reduced.

The present invention has been made in view of such a point, and a cylindrical workpiece is bent or an axis connecting between each center of a headstock and a tailstock, and a moving axis of a grindstone or a cylindrical workpiece. It is an object of the present invention to provide an automatic cylindrical grinding device capable of ensuring a precise cylindricity by automatically adjusting the feed amount of a grinding wheel base even when the grinding wheels are not parallel.

It is another object of the present invention to provide an automatic cylindrical grinding device capable of preventing a grinding chatter vibration and ensuring a precise cylindricity by bringing a claw portion of a steadying device into contact with a cylindrical workpiece in an optimum state.

[Configuration of the invention]

(Means for Solving the Problems) In order to solve the above-mentioned gantry, the present invention provides a grindstone table for rotatably supporting a grindstone for grinding a cylindrical workpiece, and moving the grindstone table in a direction perpendicular to the axial direction of the cylindrical workpiece. An automatic cylindrical grinding device comprising: a wheel head feeding means for moving; and a means for relatively moving the cylindrical workpiece and the grinding wheel in the axial direction. The grinding apparatus further automatically measures the diameter of the cylindrical workpiece. Means, connected to the relative moving means, the grinding wheel head feeding means and the diameter measuring means, by the axial position signal of the cylindrical workpiece from the relative moving means and the diameter signal from the diameter measuring means, the cylindrical workpiece Determining means for calculating each diameter at each position in the axial direction and determining whether or not the difference between the calculated maximum diameter and minimum diameter is within an allowable value; A correction value calculating means for calculating a correction amount of grinding that error is within the tolerance,
A control device having a grindstone head feed means control means for controlling a feed amount of the grindstone head feed means in accordance with a correction signal from the correction value calculating means; and a grindstone arranged on a side opposite to the grindstone head and provided on a cylindrical workpiece. An automatic steadying device having an abutting means contacting from a side opposite to the automatic steadying device; and a control means connected to the automatic steadying device and adjusting a contact force of the abutting means. Is connected to a feed screw mechanism.

The present invention also provides a grinding wheel base for rotatingly supporting a grinding wheel for grinding a cylindrical workpiece, a grinding wheel table feeding means for moving the grinding wheel table in a direction orthogonal to the axial direction of the cylindrical workpiece, and an axial hole between the cylindrical workpiece and the grinding wheel. Means for relatively moving the grinding wheel, wherein the grinding device is further disposed on a side facing the grinding wheel table, and abuts against the cylindrical workpiece from a side facing the grinding wheel. An automatic steady rest device comprising means for detecting whether or not the contact means of the automatic steady rest device, which is disposed on the grinding wheel base side and abuts on the cylindrical workpiece from the grinding wheel side, has come into contact with the cylindrical workpiece; A touch sensor device provided with a touch sensor for performing the operation, and a contact force of the contact means of the automatic steady rest device which is connected to the automatic steady rest device and the touch sensor device and which is close to zero by a detection signal from the touch sensor. It is characterized by comprising control means for controlling the movement of the abutment means so that the.

(Operation) According to the present invention, after the primary grinding operation is completed, the diameter of the cylindrical workpiece is measured at each position in the axial direction by the diameter measuring means, and the diameter error at each position is within an allowable value. Then, the feed amount of the wheel head feed means is calculated, and a second grinding operation is performed on the wheel head based on the calculated feed amount.
Thereby, correction grinding is performed at each position in the axial direction of the cylindrical workpiece, and high-density cylindricity is secured over the entire axial direction of the cylindrical workpiece.

Further, according to the present invention, when the contact means of the automatic steady rest device abuts on the cylindrical workpiece and the cylindrical workpiece bends, the deflection is detected by the touch sensor, and the cylindrical workpiece is positioned at the optimum position. The operation of the contact means of the automatic steady rest device is controlled by the control means so that the contact is made.

(Example) Hereinafter, an example of the present invention is described with reference to drawings.

1 to 3 show an embodiment of an automatic cylindrical grinding apparatus according to the present invention. In FIG. 1, reference numeral 11 denotes a headstock 12 for rotatably supporting both ends of a cylindrical workpiece W and a center. This is a processing table on which the press table 13 is mounted. The processing table 11 is mounted on a bed 14 and is slidable on the bed 14 in the same direction as a line connecting the spindle 12a of the headstock 12 and the tailstock 13a of the tailstock 13. The sliding operation of the processing table 11 is fixed to a ball screw 15 disposed on the bed 14, a processing table moving servo mote (hereinafter referred to as a "processing table motor") 16 for rotating and driving the ball screw 15, and the processing table 11. Nut member 17 screwed with ball screw 15
This is performed by a processing table moving means consisting of

Reference numeral 18 denotes a grindstone table which rotatably supports a grindstone 19 for grinding. The grindstone table 18 is mounted on a bed 21 so as to move the grindstone 19 in a direction perpendicular to the axis of the cylindrical workpiece W. The movement of the grinding wheel head 18 is also performed by a grinding wheel head feeding means including a ball screw 22, a grinding wheel head feeding servomotor (hereinafter referred to as a “wheel head motor”) 23 and a nut member 24, similarly to the processing table 11. Done.

An automatic diameter measuring device 30 for automatically measuring the diameter of the cylindrical workpiece W is provided at a position adjacent to the grindstone table 18. As shown in FIG. 2, the automatic diameter measuring device 30
A measuring part comprising an upper sensor 31a abutting on the upper outer peripheral end of the cylindrical workpiece W and a lower sensor 31b abutting on the lower outer peripheral end, and the lower sensor 31b is made to correspond to the diameter of the cylindrical workpiece W to be measured. And a sensor drive unit that moves up and down. The sensor drive unit is composed of, for example, a piston 32 connected to the lower sensor 31b, and an actuator 33 for driving the piston 32 up and down.

The measurement unit and the sensor drive unit are supported by a support frame 34, which slides on a support table 35 disposed adjacent to the grindstone table 18 in a direction perpendicular to the axis of the cylindrical workpiece W. It is mounted as possible. 36 is a support frame
This is a hydraulic cylinder that reciprocates 34.

On the side opposite to the grindstone table 18 with the cylindrical workpiece W interposed therebetween, an automatic steady rest device 40 having a claw contacting the outer peripheral portion of the cylindrical workpiece W is provided. Automatic steady rest device 40
As shown in FIG. 3, the outer peripheral portion of the cylindrical workpiece W is provided with a horizontal claw portion 41a that abuts in the horizontal direction toward the grindstone 19, and a vertical claw portion 41b that abuts upward from the lowermost portion. ing.
The horizontal claw 41a is attached to a slide block 42 having a screw hole (not shown) formed therein. The sliding block 42 is supported slidably in the horizontal direction with respect to the support bracket 43, and the screw shaft 44 is separated from the screw hole. The screw shaft 44 is connected to a horizontal torque motor 45 and can be driven to rotate. The vertical claw 41b is attached to one end of a swing lever 46 that is swingably attached to the support bracket 43 in a vertical plane. Swing lever 46
The tip end of a screw shaft 47 abuts the other end of the screw shaft 47 from the vertical direction, so that the swing lever 46 can swing vertically by the vertical movement of the screw shaft 47. The screw shaft 47 has its upper end screwed to and connected to a rotary block 49 having a screw hole 48 formed therein. The rotating block 49 is rotatably supported by the support bracket 43 and is connected to the vertical torque motor 51.

A plurality of the automatic steady rests 40 having such a configuration are arranged at appropriate intervals according to the axial length of the cylindrical workpiece W.

Machining table motor 16, wheel head motor 23, actuator 33 of automatic diameter measuring device 30, and automatic steady rest device 40
The horizontal torque motor 45 and the vertical torque motor 51 are connected to a control device for controlling their operations, for example, a CNC device 60 by a signal line.

FIG. 4 is a block diagram showing the configuration of the control device 60.

The control device 60 includes a measurement value input unit 61 to which a diameter measurement value at each axial position of the cylindrical workpiece W as the workpiece is input.
have. This measured value input unit 61 is an automatic diameter measuring device
30 and connected to the control unit 62 of the machining table motor 16,
A diameter measurement value is input from the automatic diameter measuring device 30, and a position signal of the processing table 11, that is, a position signal of the cylindrical workpiece W is input from the processing table motor control unit 62.

The diameter measurement value at each axial position of the cylindrical workpiece W input to the measurement value input unit 61 is stored in the memory 63.

The control device 60 has a central processing unit (CPU) 64 that compares the measured diameter values at each position in the axial direction stored in the memory 63 and determines whether the difference between the maximum diameter and the minimum diameter is within an allowable value. . Further, the control device 60 has a correction value calculation unit 65, and can calculate the correction grinding amount at each axial position of the cylindrical workpiece W when the diameter difference is not within the allowable value.

The correction value calculation unit 65 is connected to the control unit 66 of the wheel head motor 23, and issues a control signal to cause the wheel head motor 23 to perform a predetermined correction grinding operation.

The control device 60 further includes the claw portions 42a,
The control unit 67 includes a control unit 67 that controls the contact force of the contact point 41b, and the control unit 67 is connected to the CPU 64.

Next, the operation of this embodiment having such a configuration will be described with reference to the flowchart of FIG. When the operation switch of the automatic cylindrical grinding device is turned on, first, the horizontal torque motor 45 and the vertical torque motor 51 of the automatic steady rest device 40 are operated, and the horizontal pawl portion 41a and the vertical pawl portion 41b are brought into contact with the cylindrical workpiece with a constant contact force. Press it against W (step S1). In this way, the wobble of the cylindrical workpiece W
Start the specified grinding work by rotating the 19 (step
S2). During the grinding operation, since the diameter of the cylindrical workpiece W decreases, the claw portions 41a and 41b of the automatic steady rest device 40 are moved and adjusted,
The contact force is kept constant (step S3). These claws 41a,
The adjusting method of 41b includes horizontal and vertical torque motors 45, 51
Is operated, and the pawl portions 41a, 41b are pressed against the cylindrical workpiece W until the torque of the torque motors 45, 51 reaches the set torque, thereby making the contact force constant. When a plurality of the pawls 41a and 41b are provided in the axial direction of the cylindrical workpiece W, the pressing torque of each of the pawls 41a and 41b is sequentially adjusted in accordance with the axial movement position of the grindstone 19. And maintain the contact force constant.

Grinding is performed in the order of rough grinding to finish grinding, and the grinding operation is completed (step S4). When the grinding is completed, the grindstone 19 is temporarily retracted (step S5), and then the automatic diameter measuring device 30
Of the upper and lower sensors 31a, 31b by moving the supporting frame 34 in the direction of the cylindrical workpiece W.
Holds the cylindrical workpiece W in the vertical direction. Until the upper and lower sensors 31a and 31b come into contact with the upper and lower outer peripheral ends of the cylindrical workpiece W, the cylindrical workpiece W depends on the operation amount of the actuator 33 necessary to move the upper and lower sensors 31a and 31b. Step S6) is to measure the diameter of The diameter measurement is performed at each position in the axial direction of the cylindrical workpiece W by relatively moving the machining table 11 and the automatic diameter measuring device 30 in the axial direction, and the measured value at each position is stored in the memory 63. .

CPU 64 compares the stored measurement results and determines whether the difference between the maximum diameter and the minimum diameter is within an allowable value (step S7). If the diameter difference is not within the tolerance, the required grinding cylindricity has not been obtained,
It is determined that grinding correction is necessary.

Therefore, in this case, first compare the measurement results to determine the minimum diameter.
Dmin is recognized (step S8). Subsequently, the grinding correction value at each position in the axial direction is calculated by the correction value calculating unit 65 (step S9). The calculation of the correction value is performed, for example, using the following calculation formula.

an: Grinding correction value Dn: Diameter at n position in the axial direction The calculated correction value is sent to the wheel head motor control unit 66,
Correction grinding is performed while moving the grindstone motor 23 by a predetermined amount (step S10).

After the correction grinding, the diameter is measured again, and when the diameter difference falls within the allowable value, the grinding cycle ends.

As described above, according to the present embodiment, the automatic diameter measuring device 30 is provided, the diameter of the cylindrical workpiece W after the grinding at the axial position is measured, and the correction grinding is performed so that the diameter difference is within the allowable value. Therefore, the axis of the cylindrical workpiece W is not parallel to the moving axis direction of the grindstone or the cylindrical workpiece W due to poor engagement between the center hole of the cylindrical workpiece W and the headstock and tailstock center. Also, a predetermined grinding cylindricity can be obtained.

In addition, since the movement of the claw portions 41a and 41b of the automatic steadying device 40 can be automatically adjusted according to the feed amount of the grindstone 19 during the grinding, the constant constant contact with the cylindrical workpiece W can be achieved. The pawl portions 41a and 41b can be pressed by the contact force, and chatter vibration and the like during grinding can be prevented.

In this embodiment, an example is shown in which the grindstone table 18 is fixedly arranged in the axial direction of the cylindrical workpiece W, and the cylindrical workpiece W is moved in the axial direction by moving the processing table 11, but conversely, the cylindrical The present invention can also be applied to a system in which the movement of the workpiece W in the axial direction is stopped and the grindstone table 18 is moved in the axial direction. In this case, the machining table 11 and the machining table motor 16 become unnecessary, and a means for moving the grindstone table 18 in the axial direction of the cylindrical workpiece W is required.

Although the example shown in FIG. 2 is shown as the diameter measuring device, the structure is not limited as long as the diameter of the cylindrical workpiece W can be automatically measured at each axial position.

6 to 8 show another embodiment of the present invention. In these drawings, the same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted.

In the present embodiment, the horizontal claw portion of the automatic
A touch sensor device 70 for detecting that 41a has come into contact with the cylindrical workpiece W is provided. That is, as shown in FIG. 7, the touch sensor device 70 has a touch sensor 71 that comes into contact with the outer peripheral end of the cylindrical workpiece W from the side facing the horizontal claw portion 41a. The touch sensor 71 is attached and held at the tip of a rod-shaped support frame 72,
The touch sensor moving servomotor 73 is connected to the rear end of the support frame 72. This servo motor 73
Is to move the support frame 72 in the front-rear direction, and by the support table 74 fixed at the upper position of the grindstone table 18,
It is supported at an angle.

In the present embodiment, the automatic steady rest device 40 is disposed at a central position in the axial length of the cylindrical workpiece W.

The machining table motor 16, the grinding wheel motor 23, the touch sensor 71 of the touch sensor device 70, the servo motor 73, and the servo motors 45 and 51 of the automatic steady rest device 40 are controlled by a control device that controls these operations, such as a CNC device 80. Connected by wires.

As shown in FIG. 8, the control device 80 includes a touch sensor device control unit 81 that controls the servo motor 73 of the touch sensor device 70, and an automatic steady rest that controls the feed of the claw portions 41a and 41b of the automatic steady rest device 40. A device control unit 82 is provided. These control units 81 and 82 are connected to the CPU 83.
As in the above-described embodiment, the machining table motor control unit 8
5. Connected to the wheel head motor control unit 86. Further, the control device 80 has a memory 84 connected to the CPU 83.

Next, the operation of this embodiment having such a configuration will be described with reference to the flowchart shown in FIG.

When the operation switch of the automatic cylindrical grinding device is turned on, first, the machining table motor 16 is driven to move the machining table 1 so that the touch sensor device 70 comes to the front position of the automatic steady rest device 40 (step P1). Touch sensor device
By driving the sensor driving servomotor 73, the support frame 72 is protruded so that the touch sensor 71 comes to a position orthogonal to the axis of the cylindrical workpiece W (step P2).

The grindstone motor 23 is driven until the touch sensor 71 comes into contact with the cylindrical workpiece W to advance the grindstone head 18 and stop immediately after the contact (step P3). Then touch sensor 71
Grindstone motor until it comes into non-contact with cylindrical workpiece W
23, the grindstone head 18 is moved backward, and after the non-contact, the grindstone motor 23 is stopped immediately (step P
Four). The horizontal torque motor 45 of the automatic steady rest device 40 is operated to move the horizontal claw portion 41a forward (step P5).
When the claw portions 41a and 41b come into contact with the cylindrical workpiece W and the cylindrical workpiece W is bent, the bending is detected by the tap sensor 71.
That is, the touch sensor arranged in a non-contact state
It is determined whether 71 has contacted the cylindrical workpiece W (step P6). As soon as the cylindrical workpiece W warps and comes into contact with the touch sensor 71, the movement of the horizontal claw portion 41a is stopped (step P7). Next, the servo motor of the touch sensor device 70
Drive the 73 and retract the touch sensor 71 to move the cylindrical workpiece W
(Step P8).

In this way, the grinding is started by bringing the horizontal claw portion 41a into optimal contact with the outer peripheral end of the cylindrical workpiece W and rotating the grindstone 19 (step P9).

As described above, according to the present embodiment, the contact force of the claw portion 41a can be made nearly zero, and the horizontal claw portion of the automatic anti-sway device can be optimally bent without bending the cylindrical workpiece.
41a can be brought into contact with the outer peripheral end of the cylindrical workpiece W. Thereby, chatter vibration during grinding work of the cylindrical workpiece W can be reliably prevented.

This embodiment has a particularly excellent effect when grinding an elongated cylindrical workpiece W which undergoes large bending deformation when the pressing force of the claw portion is constant.

〔The invention's effect〕

As described above, according to the present invention, the correction grinding can be automatically performed so that the grinding cylindricity of the cylindrical workpiece is within the allowable value. Grinding can be performed.

Further, since the claw portion of the automatic steady rest device can always be pressed against the cylindrical workpiece with the same contact force, it is possible to surely prevent chatter vibration or the like during the grinding operation.

In particular, when grinding an elongated cylindrical workpiece, the contact force of the claw portion of the automatic steadying device can be made almost zero, and highly accurate grinding can be performed without causing the bending of the cylindrical workpiece. .

The automatic cylindrical grinding device according to the present invention has a particularly excellent effect when applied to the grinding operation of an elongated cylindrical workpiece.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an automatic cylindrical grinding device according to the present invention, FIG. 2 is a side view showing an example of an automatic diameter measuring device, FIG.
FIG. 4 is a block diagram showing a configuration of a control device, FIG. 5 is a flowchart showing a grinding process of a grinding device according to the present invention,
FIG. 6 is a block diagram showing another embodiment of the present invention, FIG. 7 is a partial sectional view showing a use state of the automatic steady rest device and the touch sensor device, FIG. 8 is a block diagram showing a configuration of the control device, FIG. 9 is a flowchart showing a grinding process according to the second embodiment. 11 ... machining table, 12 ... headstock, 13 ... tailstock, 16
…… Processing table motor, 18… Whetstone table, 19 …… Whetstone,
23 …… Wheel head motor, 30 …… Automatic diameter measuring device, 31a, 31
b: Upper sensor, lower sensor, 33: Actuator, 40: Automatic anti-sway device, 41a, 41b: Claw, 45 ...
… Horizontal torque motor, 51 …… Vertical torque motor, 60,80
… Control device, 70… Touch sensor device, 71… Touch sensor.

Claims (3)

(57) [Claims] 1. A grindstone table for rotatably supporting a grindstone for grinding a cylindrical workpiece, a grindstone table feed means for moving the grindstone table in a direction orthogonal to the axial direction of the cylindrical workpiece, and an axial direction between the cylindrical workpiece and the grindstone. An automatic cylindrical grinding apparatus comprising: a means for automatically measuring a diameter of a cylindrical workpiece; and a relative moving means, a wheel head feeding means and a diameter measuring means. Connected to the axial position signal of the cylindrical workpiece from the relative moving means and the diameter signal from the diameter measuring means,
Calculating the diameter at each position in the axial direction of the cylindrical workpiece, determining means for determining whether or not the difference between the calculated maximum diameter and the minimum diameter is within an allowable value; and A correction value calculating means for calculating a correction grinding amount such that the diameter error is within an allowable value, and a grinding wheel head feeding means controlling means for controlling a feeding amount of the wheel head feeding means by a correction signal from the correction value calculating means. A control device having an abutment means disposed on a side facing the grindstone table and having contact means for abutting the cylindrical workpiece from the side facing the grindstone; and A control means for adjusting a contact force of the contact means, wherein the contact means of the automatic steady rest device is connected to a feed screw mechanism. 2. The abutment means of the automatic steady rest device comprises, on the outer peripheral portion of the cylindrical workpiece, a horizontal claw portion abutting horizontally toward the grindstone and a vertical claw portion abutting upward from below. The feed screw mechanism includes a horizontal feed screw mechanism and a vertical feed screw mechanism each including a combination of a relatively rotating screw shaft and a screw screw block of the screw shaft connected to the horizontal claw portion and the vertical claw portion, respectively, The automatic cylindrical grinding device according to claim 1, wherein the horizontal feed screw mechanism and the vertical feed screw mechanism are driven independently of each other. 3. A grindstone table for rotatably supporting a grindstone for cylindrical workpiece grinding, a grindstone table feed means for moving the grindstone table in a direction orthogonal to the axial direction of the cylindrical workpiece, and an axial direction of the cylindrical workpiece and the grindstone. Means for relatively moving the grinding wheel, wherein the grinding device is further disposed on a side facing the grinding wheel table, and abuts against the cylindrical workpiece from a side facing the grinding wheel. An automatic steady rest device comprising means for detecting whether or not the contact means of the automatic steady rest device, which is disposed on the grinding wheel base side and abuts on the cylindrical workpiece from the grinding wheel side, has come into contact with the cylindrical workpiece; A touch sensor device provided with a touch sensor for performing the operation, and a contact force of the contact means of the automatic steady rest device which is connected to the automatic steady rest device and the touch sensor device and which is close to zero by a detection signal from the touch sensor. Automatic cylindrical grinding apparatus characterized by comprising control means for controlling the movement of the abutment means so that the.