JPH0392267A - Automatic cylindrical grinding attachment - Google Patents

Abstract

PURPOSE:To improve the grinding workability by constituting the system in such a manner that automatic corrective grinding is conducted so that the grinding cylindricity of a cylindrical work comes within the allowance. CONSTITUTION:At the completion of the first grinding operation, the diameters of a cylindrical work W are measured at various positions in the axial direction of the work W, using a diameter measuring means 30. Next, the feed per revolution of a wheel spindle stock sending means 23 is computed by a controlling device 60 so that the diametral errors at respective positions come within the allowance, and, based on the feed per revolution thus computed, the second grinding operation is applied to a wheel spindle stock 18. With this contrivance, the corrective grinding of the cylindrical work W can be conducted at respective positions in the axial direction of the work W, thereby ensuring highly accurate cylindricity over the entire range of the axial direction of the cylindrical work W.

Description

DETAILED DESCRIPTION OF THE INVENTION [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 that can accurately grind a long and narrow cylindrical workpiece.

(Prior art) In order to process a long and slender cylindrical workpiece with high precision, the axis connecting the headstock and tailstock, which rotatably support both ends of the cylindrical workpiece, and the axis of movement of the grindstone or the cylindrical workpiece must be aligned. Parallelism needs to be adjusted. In addition, a steady rest device with a claw that comes into contact with the cylindrical workpiece is placed in a position facing the grindstone head to prevent the middle part of the cylindrical workpiece from bending and causing chatter vibrations during grinding. .

Conventionally, such parallelism adjustment and the adjustment of the claw portion of the steady rest device were manually performed, but in recent years, automation of work rests has been promoted due to the demand for automation of grinding devices. For example, a grinding machine equipped with a sizing device that measures the machining diameter of a cylindrical workpiece and a rest device that can detect when the claws of the steady rest device have come into contact with the cylindrical workpiece (Special Publications No. 6)
2-5751) has been proposed.

In the above-mentioned conventional grinding machine with a rest device, the sizing device detects when the claw of the steady rest device comes into contact with the cylindrical workpiece, prevents the rest device from engaging poorly, and also prevents the rest device from pushing in as required. quantity can be secured.

(Problems to be Solved by the Invention) When a cylindrical workpiece is long and thin, the vicinity of the center part may be greatly bent due to the pressing of the claw part, or the center hole of the cylindrical workpiece may not be properly engaged with the center of the headstock or tailstock. For example, the axis of the cylindrical workpiece may not be parallel to the axis of movement 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, resulting in the grinding cylindricity (cylindrical It is not possible to solve the problem that the maximum difference in the diameter of the workpiece in the axial direction is not within the allowable value and the machining accuracy decreases.

Further, when the cylindrical workpiece is long and narrow, if the claw portion of the steady rest device does not reliably contact the cylindrical workpiece, grinding chatter vibration may occur during grinding, which may adversely affect the ground surface.

On the other hand, when the pressing force of the claws increases, the cylindrical workpiece easily bends, resulting in a problem of reduced machining accuracy.

The present invention has been made in consideration of these points,
To automatically adjust the feed amount of the grinding wheel head even if the cylindrical workpiece is bent or the axis connecting the centers of the headstock and the center head is not parallel to the axis of movement of the grinding wheel or the cylindrical workpiece. The present invention aims to provide an automatic cylindrical grinding device that can ensure precise cylindricity.

Another object of the present invention is to provide an automatic cylindrical grinding device that allows the claws of the steady rest device to contact the cylindrical workpiece in an optimal state, thereby preventing grinding chatter vibrations and ensuring precise cylindricity.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a grindstone head that rotatably supports a grinding wheel for grinding a cylindrical workpiece, and a grindstone head that moves in a direction perpendicular to the axial direction of the cylindrical workpiece. An automatic cylindrical grinding device comprising: a grindstone head feeding means for moving a cylindrical workpiece and a grindstone relative to each other in an axial direction;
A means for automatically measuring the diameter of the cylindrical workpiece, connected to the relative moving means, the grindstone feeding means, and the diameter measuring means, the axial position signal of the cylindrical workpiece from the relative moving means and the diameter signal from the diameter measuring means. and control means for calculating the respective diameters at each position in the axial direction of the cylindrical workpiece, and controlling the feed amount of the grinding wheel head feeding means so that the diameter error at each position is within a tolerance value. It is characterized by

The present invention also provides a grindstone head that rotatably supports a whetstone for grinding a cylindrical workpiece, a grindstone feeder that moves the whetstone head in a direction orthogonal to the axial direction of the cylindrical workpiece, and a grindstone head that moves the cylindrical workpiece and the grindstone in the axial direction. An automatic cylindrical grinding device comprising: means for moving the grinding device relative to the grinding device; an automatic steady rest device equipped with contact means;
A touch sensor device equipped with a touch sensor that is placed on the grindstone side and contacts the cylindrical workpiece from the grindstone side, an automatic steady rest device, and an automatic steady rest device that is connected to the touch sensor device and uses a detection signal from the touch sensor. and control means for controlling the operation of the contact means.

(Function) According to the present invention, after the first grinding operation is completed, the diameter at each position in the axial direction of the cylindrical workpiece is measured by the diameter measuring means, and the diameter error at each position is kept within the allowable value. The feed amount of the grindstone feeding means is calculated, and the ffi secondary grinding operation is performed on the grindstone head based on the calculated feed amount. As a result, correction grinding is performed at each position in the axial direction of the cylindrical workpiece, and highly accurate cylindricity is ensured 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 comes into contact with the cylindrical workpiece and the cylindrical workpiece is deflected, the deflection is detected by the touch sensor, and the contact means is moved to the optimum position to move the cylindrical workpiece. The control means controls the operation of the abutment means of the automatic steady rest device so that the automatic steady rest device abuts the automatic steady rest device.

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

1 to 3 are diagrams showing an embodiment of an automatic cylindrical grinding apparatus according to the present invention. In FIG. This is a processing table on which a stand 13 is mounted. The processing table 11 is mounted on the bed 14 and is capable of sliding on the bed 14 in the same direction as a line connecting the main shaft 12a of the headstock 12 and the tailstock shaft 13a of the tailstock 13. The sliding movement of the machining table 11 is achieved by a ball screw 15 disposed on the bed 14, a servo motor for moving the machining table (hereinafter referred to as "machining table motor") 16 that rotates the ball screw 15, and a servo motor fixed to the machining table 11. This is carried out by a processing table moving means consisting of a ball screw 15 and a nut member 17 screwed together.

Reference numeral 18 denotes a grindstone stand that rotatably supports one grinding wheel, and the grindstone stand 18 is mounted on a bed 21 so as to be able to move one grindstone in a direction orthogonal to the axis of the cylindrical workpiece W. There is. As with the processing table 11, the movement of the grindstone head 18 is also carried out by a ball screw 22 and a grindstone feed servo motor (hereinafter referred to as "grindstone motor J") 2 that rotationally drives the ball screw 22.
3 and a nut member 24.

An automatic diameter measuring device 30 that automatically measures the diameter of the cylindrical workpiece W is disposed adjacent to the grindstone head 18. As shown in FIG.
a and a lower sensor 31b that abuts the lower outer peripheral end thereof, and a sensor drive unit that moves the lower sensor 3lb up and down in accordance with the diameter of the cylindrical workpiece W to be measured. The sensor drive section is, for example, the lower sensor 31b.
The piston 32 is connected to a piston 32, and an actuator 33 that drives the piston 32 up and down.

The measuring section and the sensor driving section are supported by a support frame 34, and this support frame 34 slides on a support stand 35 disposed adjacent to the grindstone head 18 in a direction perpendicular to the axis of the cylindrical workpiece W. Possibly installed. Reference numeral 36 is a hydraulic cylinder that reciprocates the support frame 34.

On the side facing the grindstone head 18 with the cylindrical workpiece W in between, an automatic steady rest device 40 having a claw portion that comes into contact with the outer periphery of the cylindrical workpiece W is disposed. As shown in FIG. 3, the automatic steady rest device 40 has a horizontal claw portion 41a that abuts the outer circumference of the cylindrical workpiece W in the horizontal direction toward the grindstone 19.
and a vertical claw portion 4lb that abuts upward from the bottom. The horizontal claw portion 41a is attached to a sliding block 42 having a screw hole (not shown) formed therein. The sliding block 42 is supported by a support bracket 43 so as to be slidable in the horizontal direction, and a screw shaft 44 is screwed into the screw hole. This screw shaft 44 is connected to a horizontal torque motor 45.
It is connected to and can be rotationally driven. Further, the vertical claw portion 4lb is attached to one end portion of a swing lever 46 that is attached to the support bracket 43 so as to be swingable within a vertical plane. The tip of a screw shaft 47 abuts the other end of the swing lever 46 from the vertical direction, so that the swing lever 46 can swing vertically due to the vertical movement of the screw shaft 47. The screw shaft 47 is connected at its upper end to a rotating block 49 having a screw hole 48 formed therein by being screwed into the screw hole 48 . This rotating block 4
9 is rotatably supported by a support bracket 43 and connected to a vertical torque motor 51 .

A plurality of automatic steady rest devices 40 having such a configuration are arranged at appropriate intervals depending on the axial length of the cylindrical workpiece W.

The processing table motor 16, the grindstone motor 23, the actuator 33 of the automatic diameter measuring device 30, the horizontal torque motor 45 of the automatic steady rest device 40, and the vertical torque motor 5
1 is a control device that controls these operations, such as a CNC
It is connected to the device 60 by a signal line.

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

The control device ri 160 has a measurement value input section 61 into which diameter measurement values at each position in the axial direction of the cylindrical workpiece W, which is the object to be measured, are input. This measurement value input section 61 is connected to the automatic diameter measuring device 30 and the control section 6 of the processing table motor 16.
2, the diameter measurement value from the automatic diameter measuring device 30 is transmitted from the processing table motor control unit 62 to the processing table 11.
The position of the cylindrical workpiece W, that is, the position signal of the cylindrical workpiece W, is manually input.

The diameter measurement values at each position in the axial direction of the cylindrical workpiece W input to the measurement value input section 61 are stored in the memory 63.

The control device 60 uses a central processing unit (CPU) 64 that compares the measured diameter values at each axial position stored in the memory 63 and determines whether the difference between the maximum and minimum diameters is within a tolerance value.
have. The control device 60 also includes a Katsura positive value calculation unit 65.
, and when the diameter difference is not within an allowable value, it is possible to calculate the corrected grinding amount at each position in the axial direction of the cylindrical workpiece W.

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

The control device 60 further controls the claw portion 4 of the automatic steady rest device 40.
1a. It has a control section 67 that controls a contact force of 4 lb, and this control section 67 is connected to the CPU 64.

Next, regarding the operation of this embodiment having such a configuration,
This will be explained using the flowchart shown in FIG. When the operation switch of the automatic cylindrical grinding device is turned on, the horizontal torque motor 45 and vertical torque motor 51 of the automatic steady rest device 40 are activated, and the horizontal claw portion 41a and the vertical claw portion 41 are activated.
b is pressed against the cylindrical workpiece W with a constant contact force (step Sl).

While resting the cylindrical workpiece W in this way, the grindstone 19 is driven to rotate and a predetermined grinding operation is started (step S2). During the grinding operation, the diameter of the cylindrical workpiece W decreases, so the claws 41a and 41b of the automatic steady rest device 40
is moved and adjusted to maintain a constant contact force (step S3
). To adjust the claws 41a and 4lb, the horizontal and vertical torque motors 45 and 51 are operated and controlled until the torque of the torque motor 45 and 51 reaches the set torque.
There is a method of pressing 1a, 41b against the cylindrical workpiece W to keep the contact force constant. Further, when a plurality of claw portions 41a and 41b are arranged in the axial direction of the cylindrical workpiece W, the grinding wheel 19
The pressing torque of each claw portion 41a, 41b is sequentially adjusted in accordance with the axial movement position of , and the contact force is maintained constant.

Grinding is performed in the order of rough grinding to finish grinding, and the grinding work is completed (step S4). When the grinding is finished, the grinding wheel 19 is moved back (step S5), and then the hydraulic cylinder 36 of the automatic diameter measuring device 30 is activated, and the support frame 3
4 in the direction of the cylindrical workpiece W, and the upper and lower sensors 31a and 31b support the cylindrical workpiece W in the vertical direction. The cylindrical workpiece W is moved by the amount of operation of the actuator 33 required to move the upper and lower sensors 31a and 3lb 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 diameter of is measured (step S6). This diameter measurement is performed at each axial position of the cylindrical workpiece W by relatively moving the processing table 11 and the automatic diameter measuring device 30 in the axial direction, and the diameter measurement value at each position is stored in the memory 63. Ru.

In the CPU 64, the stored measurement results are compared,
It is determined whether the difference between the maximum diameter and the minimum diameter is within a tolerance value (step S7).

If the diameter difference is not within the allowable value, it means that the required grinding cylindricity has not been obtained, and it is determined that grinding correction is necessary.

Therefore, in this case, first, each measurement result is compared to recognize the minimum diameter value DIIin (step S8).

Subsequently, the grinding correction value at each position in the axial direction is calculated by the correction value calculating section 65 (step S9). This correction value is calculated using, for example, the following calculation formula.

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

After the corrective grinding, the diameter is measured again, and when the diameter difference falls within the tolerance, the grinding cycle ends.

As described above, according to the present embodiment, the automatic diameter measuring device 30 is provided to measure the diameter after grinding at each position in the axial direction of the cylindrical workpiece W, and corrective grinding is performed so that the diameter difference is within the tolerance value. Therefore, if the axis of the cylindrical workpiece W is not parallel to the axis of movement of the grindstone or the cylindrical workpiece W due to poor engagement between the center hole of the cylindrical workpiece W and the centers of the headstock and tailstock, etc. Even with this, a given grinding cylindricity can be obtained.

Furthermore, since the movement of the claw portions 41a4lb of the automatic steady rest device 40 can be automatically adjusted in accordance with the feed amount of the grindstone 19 during grinding, a constant contact force is always maintained against the cylindrical workpiece W. The claw portions 41a and 41b can be pressed,
It is possible to prevent chatter vibrations during grinding.

In this embodiment, an example was shown in which the grindstone head 18 is fixedly arranged with respect to the axial direction of the cylindrical workpiece W, and the cylindrical workpiece W is moved in the axial direction by movement of the processing table 11. It can also be applied to a system in which the axial movement of the workpiece W is stopped and the grindstone head 18 is moved in the axial direction.

In this case, the processing table l1 and the processing table motor 16 become unnecessary, and a means for moving the grindstone head 18 in parallel to the axial direction of the cylindrical workpiece W is required.

In addition, although the example shown in Fig. 2 was shown as a 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 other embodiments of the invention. In these figures, the same components as those in the above-described embodiments are denoted by the same reference numerals, and their explanations will be omitted.

In this embodiment, a touch sensor device 70 for detecting that the horizontal claw portion 41a of the automatic steady rest device 40 has come into contact with the cylindrical workpiece W is provided. That is,
As shown in FIG. 7, the touch sensor device 70 includes a touch sensor 71 that comes into contact with the outer peripheral end of the cylindrical workpiece W from the side opposite to the horizontal claw portion 41a. The touch sensor 71 is attached and held at the tip of a rod-shaped support frame 72, and a servo motor 73 for moving the touch sensor is connected to the rear end of the support frame 72. This servo motor 73 moves the support frame 72 in the front and back direction, and is tilted and supported by a support stand 74 fixed at an upper position of the grindstone head 18.

In this embodiment, the automatic steady rest device 40 is disposed at the center of the axial length of the cylindrical workpiece W.

Processing table motor 16, grindstone motor 23, touch sensor 71 of touch sensor device 70, servo motor 73
and servo motor 45.51 of automatic steady rest device 40
is connected by a signal line to a control device that controls these operations, such as a CNC device 80.

As shown in FIG. 8, the control device rit80 includes a touch sensor device control section 81 that controls the servo motor 73 of the touch sensor device 70, and a claw section 41 of the automatic steady rest device 40.
a. Automatic steady rest device control unit 8 that controls the feed of 41b
It has 2. These control units 81 and 82 are controlled by the CPU 8.
3, and the CPU 83 is further connected to a processing table motor control section 85 and a grindstone head motor control section 86, as in the above embodiment. Further, the control device 80
It has a memory 84 connected to the PU 83.

Next, regarding the operation of this embodiment having such a configuration,
This will be explained using the flowchart shown in FIG.

When the operation switch of the automatic cylindrical grinding device is turned on, first, the processing table motor 16 is driven to move the processing table 11 so that the touch sensor device 70 comes to the front position of the automatic steady rest device 40 (step Pi). The sensor drive servo motor 73 of the touch sensor device 270 is driven to project the support frame 72 so that the touch sensor 71 is at a position perpendicular to the axis of the cylindrical workpiece W (step P2).

The grindstone motor 23 is driven to advance the grindstone 18 until the touch sensor 71 contacts the cylindrical workpiece W, and immediately stops after the contact (step P3). Subsequently, the grindstone head motor 23 is driven to move the grindstone head 18 backward until the touch sensor 71 is in a non-contact state with the cylindrical workpiece W.
Immediately after becoming non-contact, the grindstone head motor 23 is stopped (step P4). The horizontal torque motor 45 of the automatic steady rest device 40 is activated to move the horizontal claw portion 41a forward (step P5). Claw portion 41a. 4lb comes into contact with the cylindrical workpiece W, and when the cylindrical workpiece W is deflected, this deflection is detected by the touch sensor 71. That is, it is determined whether the touch sensor 71 arranged in a non-contact state has contacted the cylindrical workpiece W (step P6). When the cylindrical workpiece W bends and contacts the touch sensor 71, the horizontal claw portions 41a. Stop the movement of (Step P7)
. Subsequently, the servo motor 73 of the touch sensor device 70 is driven to retract the touch sensor 71 and separate it from the cylindrical workpiece W (step P8).

In this way, the horizontal claw portion 41a is brought into contact with the outer peripheral end of the cylindrical workpiece W in an optimal state, and the grinding wheel 19 is rotationally driven to start grinding (step P9).

As described above, according to this embodiment, the contact force of the claw portion 41a can be brought close to zero, and the horizontal claw portion 41a of the automatic steady rest device can be moved in an optimal state without deflecting the cylindrical workpiece. It is possible to make it contact with the outer peripheral end of the cylindrical workpiece W. Thereby, chatter vibration during the grinding operation of the cylindrical workpiece W can be reliably prevented.

This embodiment provides particularly excellent effects when grinding an elongated cylindrical workpiece W that undergoes large deflection deformation when the pressing force of the claw portion is kept constant.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to automatically perform correction grinding so that the grinding cylindricity of a cylindrical workpiece is within the allowable value, so that it is possible to improve grinding workability and achieve high precision. Grinding can be done.

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 reliably prevent chatter vibrations from occurring during the grinding operation.

In addition, especially when grinding a long and slender cylindrical workpiece, the contact force of the claws of the automatic steady rest device can be brought close to zero, allowing highly accurate grinding to be performed without causing the cylindrical workpiece to deflect. .

The automatic cylindrical grinding device according to the present invention exhibits particularly excellent effects when applied to the grinding work of elongated cylindrical workpieces.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the 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, and FIG. 3 is a side sectional view showing an example of an automatic steady rest device.
FIG. 4 is a block diagram showing the configuration of the control device, and FIG. 5 is a flow chart showing the grinding process of the 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 how the automatic steady rest device and the touch sensor device are used, and FIG. 8 is a block diagram showing the configuration of the control device. FIG. 9 is a flowchart showing the grinding process according to the second embodiment. 11... Processing table, 12... Headstock, 13...
・Tailstock, 16... Processing table motor, 18...
Grinding wheel head, 19... Grinding wheel, 23... Grinding wheel head motor, 3
0... Automatic diameter measuring device, 31a, 3lb... Upper sensor, lower sensor, 33... Actuator, 40
... automatic steady rest device, 41a, 4lb... claw part,
45...Horizontal torque motor, 51...Vertical torque motor, 60.80...Control device, 70...Touch sensor device, 71...Touch sensor

Claims (1)

[Scope of Claims] 1. A grindstone head that rotatably supports a whetstone for grinding a cylindrical workpiece, a grindstone head feeding means that moves the whetstone head in a direction perpendicular to the axial direction of the cylindrical workpiece, and a cylindrical workpiece and a whetstone. In an automatic cylindrical grinding apparatus, the grinding apparatus further includes: means for automatically measuring the diameter of the cylindrical workpiece; and the relative movement means, the grindstone feeding means, and the diameter. the cylindrical workpiece by an axial position signal from the relative moving means and a diameter signal from the diameter measuring means;
It is characterized by comprising a control means for calculating the respective diameters at each position in the axial direction of the cylindrical workpiece and controlling the feed amount of the grinding wheel head feeding means so that the diameter error at each position is within a tolerance value. Automatic cylindrical grinding equipment. 2. an automatic steady rest device disposed on a side facing the grindstone head and provided with abutting means for contacting the cylindrical workpiece from the side facing the grindstone; The automatic cylindrical grinding apparatus according to claim 1, further comprising a control means for adjusting the contact force of the means. 3. A grinding wheel head that rotatably supports a grinding wheel for grinding a cylindrical workpiece, a grinding wheel head feeding means that moves the grinding wheel head in a direction orthogonal to the axial direction of the cylindrical workpiece, and a relative movement of the cylindrical workpiece and the grinding wheel in the axial direction. In the automatic cylindrical grinding device, the grinding device further includes abutting means disposed on a side facing the grindstone head and abutting the cylindrical workpiece from the side facing the grindstone. an automatic steady rest device; a touch sensor device provided on the grinding wheel head side and equipped with a touch sensor that contacts the cylindrical workpiece from the grinding wheel side; a touch sensor device connected to the automatic steady rest device and the touch sensor device; An automatic cylindrical grinding device comprising: a control means for controlling the operation of the contact means of the automatic steady rest device based on a detection signal from the automatic steady rest device.