JP2004209575A - Machining apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a machining apparatus which can improve working efficiency and machining efficiency and can always accurately machine a workpiece in a required stock removal and also can elongate the life of a machining tool. <P>SOLUTION: The machining apparatus has a workpiece holding portions 4, 5 for holding a workpiece 1 on a table 3, a head portion 6 for holding a machining tool 2 and a motor 7 for the tool, and driving means 9, 10 for moving the head portion 6. The machining apparatus machines the workpiece 1 by moving the table 3 and the head portion 6 while turning the machining tool 2 in the state that the workpiece 1 engages with the machining tool 2. The machining apparatus is provided with a detecting means 15 for detecting the electric current corresponding to the torque of the motor 7 for the tool, a storing means 17 for storing the number of times of the reference movement of the table 3 and the value of the electric current corresponding to the reference torque of the motor 7 for the tool, and a torque controlling means 16 for controlling the drive of the head portion 6 by means of the driving means 9, 10 such that the detected value of the electric current corresponding to the torque becomes equal to the value of the electric current corresponding to the reference torque. The workpiece 1 is machined by moving the table 3 by the number of times of the reference movement. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a processing apparatus for processing a tooth surface of a work such as a gear and a spline shaft by grinding, shaving, or the like.
[0002]
[Prior art]
As a conventional processing apparatus of this type, for example, a polishing apparatus as shown in FIG. 5 is known. This polishing apparatus grinds a heat-treated external gear 51, which is a workpiece, according to a numerical control processing program using an internal gear wheel 52, which is a processing tool. The head stock 54 and the tail stock 55, which are work holding parts provided on a table 53 that can be moved to the center, are sandwiched between both centers.
[0003]
The head stock 54 is provided with an assist motor and a torque transmission device (not shown), and the assist motor drives the gear 51 to rotate in the forward and reverse directions via the torque transmission device.
[0004]
On the other hand, the grindstone gear 52 is rotatably mounted on a grindstone mounting head 56, and is rotatably driven in the same direction as the gear 51 by a grindstone gear motor 57 which is a tool motor attached to the grindstone mounting head 56. Has become.
[0005]
The grindstone mounting head 56 is attached to the grindstone holding portion 58 so as to be rotatable around a Z-axis crossing the X-axis so that the axis crossing angle of the grindstone gear 52 with respect to the gear 51 can be adjusted. It is mounted movably in the Z-axis direction by a Z-axis drive motor (not shown) via a moving mechanism.
[0006]
In such a polishing apparatus, by rotating the grinding wheel gear motor 57 and the assist motor for the gear 51 at rotation speeds substantially in synchronization, the rotation of the grinding wheel gear 52 causes the tooth surface pressure of the gear 51 to become excessively large. The rotation of the gear 51 is assisted by an assist motor so as not to rotate, and the torque transmission device absorbs a rotation error between the grinding wheel gear motor 57 and the assist motor.
[0007]
When grinding the gear 51 that has been heat-treated as a workpiece, the size and shape of each tooth may vary due to the thermal effects of the heat treatment. Therefore, prior to machining, the dimensions of all the teeth of the gear 51 are measured to determine an error with respect to the reference tooth, and the error is input to a correction item of the machining program as a correction amount.
[0008]
Then, in actual processing, first, the gear 51 whose dimensions have been measured is moved between the centers of the head stock 54 and the tail stock 55 in a direction approaching each other, and is sandwiched between these centers. Thereafter, the grindstone holding portion 58 is manually moved in the Z-axis (-) direction approaching the gear 51 so that the grindstone gear 52 meshes with the reference tooth of the gear 51 in a state of zero backlash. The position of the grinding wheel holding unit 58 in the Z-axis direction is stored in the apparatus as a backlash zero position.
[0009]
Thereafter, the grindstone gear motor 57 and the assist motor are rotated at rotational speeds substantially synchronized with each other, and when the rotational speed reaches a preset rotational speed in the numerical control machining program, the table 53 is designated in the X-axis direction. The table 53 is reciprocated a number of times, and each time the table 53 makes one reciprocation, the grindstone holding unit 58 is moved by the command cutting amount in the Z-axis (-) direction by the Z-axis drive motor via the moving mechanism.
[0010]
When the reciprocating movement of the table 53 reaches the designated number of times, the rotation of the grinding wheel gear motor 57 and the assist motor is stopped, and the grinding wheel holding unit 58 is moved by the Z-axis driving motor to the position at the time of starting the machining via the moving mechanism. After the movement is completed, the center of the head stock 54 and the center of the tail stock 55 are moved in a direction away from each other, and the gear 51 is taken out of the apparatus.
[0011]
Thereafter, the dimensions and the tooth profile of each tooth of the processed gear 51 are measured, and when the measured values do not satisfy the specified values, the correction amount is input to the correction item of the processing program to perform re-processing. Thus, the grinding wheel holding unit 58 is moved in the Z-axis (-) direction in consideration of the correction amount to the cutting completion value. (See, for example, Patent Document 1).
[0012]
Further, as another conventional polishing apparatus, a gear as a work and a grinding wheel as a processing tool are axially crossed and meshed with each other, and the grinding wheel is rotated by a motor to rotate the gear, thereby rotating the gear at that time. The eccentricity and wobble are detected as a function of the rotation angle of the gear, and the cutting depth of the gear and the axis crossing angle between the gear and the grinding wheel are controlled so as to correct the eccentricity and wobbling. There is also known a device in which a braking torque for braking the rotation of a gear is controlled based on the rotation angle and a pitch error of the gear is corrected (for example, see Patent Document 2).
[0013]
[Patent Document 1]
JP-A-2000-126930 (paragraph numbers 0007 to 0009, FIG. 2)
[Patent Document 2]
JP-A-6-339813 (paragraph numbers 0006 to 0013, FIG. 2)
[0014]
[Problems to be solved by the invention]
However, in Patent Document 1 and Patent Document 2, the work of measuring the dimensions of each tooth and inputting a correction value or a correction value before and after machining the gear is extremely troublesome. It is difficult to accurately measure the dimensions before processing because of the unevenness. For this reason, there is a concern that the burden on the worker may be increased and the working efficiency and the working efficiency may be reduced, and that the working may be performed extra and the life of the working tool may be shortened.
[0015]
Such a concern also arises when a spline shaft is processed using a shaving cutter.
[0016]
Accordingly, an object of the present invention, which has been made in view of the above points, is to provide a processing apparatus that can improve work efficiency and processing efficiency, can always work a workpiece with a desired processing amount with high accuracy, and can extend the life of a processing tool. To provide.
[0017]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a processing apparatus comprising: a table capable of reciprocatingly moving in a predetermined direction; a work holding portion for detachably holding a work on the table; A machining tool that can be engaged with the work and a head unit that holds a tool motor for rotating the machining tool; and a driving unit that moves the head unit in a direction that intersects with the moving direction of the table. In a processing apparatus for processing the work by moving the table and the head while rotating the processing tool in a state where the work and the processing tool are engaged, a torque current of the tool motor is detected. Torque current detection means, storage means for storing a reference number of movements of the table with respect to the workpiece and a reference torque current value of the tool motor; Based on a comparison between the torque current detection value detected by the torque current detection means and the reference torque current value stored in the storage means, the drive is performed so that the torque current detection value becomes equal to the reference torque current value. And torque control means for controlling the driving of the head unit by means, and the table is moved by the reference number of movements stored in the storage means to process the work.
[0018]
According to the first aspect of the present invention, the driving means, that is, the cutting amount of the working tool with respect to the workpiece, is set such that the torque current detection value of the tool motor becomes a preset reference torque current value when the table is moved a predetermined number of times. By controlling the number of table movements with respect to the work and the reference torque current value appropriately, the work can always be machined with a desired machining amount with high precision without measuring the dimensions before and after machining the work. In addition, the working efficiency and machining efficiency can be improved, and the service life of the machining tool can be extended.
[0019]
According to a second aspect of the present invention, in the processing apparatus of the first aspect, the workpiece is a gear, and the processing tool is a grindstone gear.
[0020]
According to the second aspect of the invention, it is possible to perform the grinding of the gear with high working efficiency and processing efficiency.
[0021]
According to a third aspect of the present invention, in the processing apparatus of the first aspect, the workpiece is a gear and the processing tool is a shaving cutter.
[0022]
According to the invention of claim 3, it is possible to perform shaving processing of the gear with high working efficiency and processing efficiency.
[0023]
According to a fourth aspect of the present invention, in the processing apparatus of the first aspect, the workpiece is a spline shaft, and the processing tool is a shaving cutter.
[0024]
According to the fourth aspect of the present invention, it is possible to perform the shaving processing of the spline shaft with high working efficiency and processing efficiency.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a processing apparatus according to the present invention will be described with reference to FIGS. 1 to 4 taking a polishing apparatus as an example.
[0026]
FIG. 1 is an external perspective view of a main part of a polishing apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a main part of a control system of the polishing apparatus shown in FIG. 1, and FIG. FIG. 4 is a flowchart showing the outline, and FIG. 4 is a flowchart showing details of the polishing operation shown in FIG.
[0027]
As shown in FIG. 1, a polishing apparatus according to the present embodiment grinds a gear 1 after heat treatment, which is a work, using an internal gear type grindstone gear 2 which is a processing tool. The head stock 4 and the tail stock 5, which are work holding units provided on the table 3 which can be moved to the center, are detachably held between the centers.
[0028]
The grindstone gear 2 is rotatably mounted on a grindstone mounting head 6 which is a head portion, and is rotated in a forward and reverse direction by a grindstone gear motor 7 which is a tool motor mounted on the grindstone mounting head 6. It is supposed to.
[0029]
The grindstone mounting head 7 is attached to the grindstone holding unit 8 so as to be rotatable around a Z-axis intersecting with the X-axis so that the axis crossing angle of the grindstone gear 2 with respect to the gear 1 can be adjusted. It is mounted movably in the Z-axis direction via a linear scale 10 by a Z-axis servomotor 9. Here, the Z-axis servo motor 9 and the linear scale 10 constitute driving means.
[0030]
The headstock 4 is provided with an assist motor and a torque transmission device as disclosed in Patent Document 1 described above, and the assist motor drives the gear 1 to rotate in the same direction as the grindstone gear 2 via the torque transmission device. By providing a brake as described in Patent Document 2 above, the rotation of the gear 1 is braked with a desired brake torque, or the gear 1 is simply dragged by the rotation of the grindstone gear 2 without providing such a mechanism. It can be turned or arbitrarily configured.
[0031]
As shown in FIG. 2, the polishing apparatus has a controller 11 for controlling the operation of the entire apparatus. By this controller 11, numerical values stored in a memory (not shown) originally provided in the apparatus are provided. In accordance with the control processing program, the grindstone gear 2 is driven by driving the grindstone gear motor 7 via the motor drive circuit 12 while reciprocating the table 3 in the X-axis direction while the gear 1 and the grindstone gear 2 are meshed. While rotating the table 3 in the forward and reverse directions, the Z-axis servomotor 9 is driven via the motor drive circuit 13 in the forward and backward movements of the table 3 to move the grinding wheel holder 8 in the Z-axis direction via the linear scale 10. Thus, the gear 1 is polished by the grindstone gear 2.
[0032]
In the present embodiment, the control system shown in FIG. 2 includes a torque current detection circuit 15 which is a torque current detection means for detecting a torque current of the grinding wheel gear motor 7, and a torque control for controlling the driving of the Z-axis servomotor 9. A torque control circuit 16 as a means, a predetermined number of reciprocating movements of the table 3 required for polishing the gear 1 after the heat treatment with a desired polishing amount, and a grinding wheel at the time of grinding (at the time of engagement between the gear 1 and the grinding wheel gear 2). A memory 17 is provided as storage means for storing a reference torque current value of the gear motor 7.
[0033]
The detected torque current value of the grinding wheel gear motor 7 detected by the torque current detection circuit 15 is supplied to the controller 11 and the torque control circuit 16. The reference torque current value stored in the memory 17 is also supplied from the controller 11 to the torque control circuit 16, where the reference torque current value is compared with the detected torque current value, and the torque is determined based on the comparison result. The drive of the Z-axis servomotor 9 is controlled via the motor drive circuit 13 so that the detected current value becomes equal to the reference torque current value. Thereby, the inter-axis distance between the gear 1 and the grinding wheel 2 is adjusted in tooth units of the gear 1 to control the cutting amount of the gear 1 by the grinding wheel 2.
[0034]
In FIG. 2, the memory 17 may share a memory for storing a numerical control machining program originally provided in the apparatus. Further, as the predetermined number of reciprocating movements of the table 3 and the reference torque current value of the grinding wheel gear motor 7 stored in the memory 17, the respective values when the gear 1 is polished to predetermined dimensions are used. For this reason, in the present embodiment, the torque current detection value detected by the torque current detection circuit 15 is supplied to the controller 11, and the torque current detection value when the gear 1 is ground to a predetermined size is used as the reference torque current value. And stored in the memory 17.
[0035]
The processing operation of the polishing apparatus according to the present embodiment will be described below with reference to FIGS.
[0036]
FIG. 3 shows an outline of the machining operation. First, both centers of the head stock 4 and the tail stock 5 are moved in a direction approaching each other, and the gear 1 to be machined is set between these two centers. (Step S <b> 1) Then, the grinding wheel holding unit 8 is manually moved in the Z-axis (−) direction approaching the gear 1 so that the grinding wheel gear 2 meshes with the gear 1 in a state of zero backlash. The position of the whetstone holding unit 8 in the Z-axis direction at that time is stored in the apparatus as a backlash zero position (step S2).
[0037]
Thereafter, the motor 7 for the grinding wheel is rotated (step S3) to start the torque current detection by the torque current detection circuit 15 (step S4), and the number of revolutions of the motor 7 for the grinding wheel is set in advance by numerical control processing. It is detected whether or not the number of revolutions in the program has been reached (step S5).
[0038]
When the grinding wheel gear motor 7 reaches the command rotation speed, the table 3 starts reciprocating movement in the X-axis direction (step S6), and every time the table 3 moves forward and backward, the Z-axis servo motor 9 The grinding wheel holding unit 8 is moved in the Z-axis (-) direction via the linear scale 10 to give a cut to the gear 1, and the amount of movement of the grinding wheel holding unit 8, that is, the cutting amount of the gear 1, will be described with reference to FIG. As described above, the gear 1 is polished under the control based on the comparison between the torque current detection value of the torque current detection circuit 15 and the reference torque current value stored in the memory 17 (step S7).
[0039]
The polishing operation in step S7 is performed for the predetermined number of reciprocating movements of the table 3 stored in the memory 17, and when the number of reciprocating movements of the table 3 reaches the predetermined number of times (step S8), the processing is terminated.
[0040]
FIG. 4 shows the details of the polishing operation in step S7 shown in FIG. 3. First, during each forward and backward movement of the table 3, the grindstone holding unit 8 moves in the Z-axis (-) direction. Then, the Z-axis servo motor 9 is driven (step S11). During the movement of the whetstone holding unit 8 in the Z-axis (-) direction, the torque control circuit 16 detects the torque current value (I) from the torque current detection circuit 15 and the reference torque current value ( (Iref) and I <Iref (step S12). If I <Iref (YES), the torque control circuit 16 causes the grinding wheel holder 8 to move in the Z-axis (-) direction. Continue moving.
[0041]
On the other hand, in step S12, if I ≧ Iref (NO), it is detected whether I = Iref (step S13), and if I = Iref (YES), the torque control circuit The drive of the Z-axis servomotor 9 is stopped by 16 to stop the movement of the grindstone holding unit 8 (step S14), and thereafter, it is detected whether the table has completed one forward or backward movement. (Step S15) If not completed (NO), the process returns to Step S12.
[0042]
In step S13, if I ≠ Iref (NO), the torque control circuit 16 sets the Z-axis servo motor 9 so that the grinding wheel holding unit 8 moves in the Z-axis (+) direction, with I> Iref. Driving is performed in the opposite direction (step S16), and the process returns to step S12.
[0043]
As described above, during each forward and backward movement of the table 3, the torque current detection value of the grinding wheel gear motor 7 detected by the torque current detection circuit 15 is different from the reference torque current value stored in the memory 17 in advance. By controlling the driving of the Z-axis servomotor 9 by the torque control circuit 16 so as to coincide with each other, the cutting amount of the grinding wheel 2 with respect to the gear 1 is adjusted in tooth units so that the cutting amount corresponds to the reference torque current value. It can be corrected automatically.
[0044]
Therefore, even if the size and shape of each tooth of the gear 1 fluctuate due to thermal effects such as expansion due to heat treatment, the dimensions of all the teeth of the gear 1 are measured before machining, and the error from the reference tooth is reduced. The gear 1 can always be polished with a desired amount of polishing with high accuracy without inputting as a correction value or measuring the dimensions of all teeth similarly after processing and reprocessing the error, so that the working efficiency and The processing efficiency can be improved, and the life of the grinding wheel 2 can be extended.
[0045]
It should be noted that the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the spirit of the invention. For example, the present invention can be effectively applied not only to a polishing apparatus using an internal gear wheel 2 but also to a polishing apparatus using an external gear wheel. The present invention can also be effectively applied to a processing device that is a cutter or a processing device in which a workpiece is a spline shaft and a processing tool is a shaving cutter.
[0046]
【The invention's effect】
According to the present invention, the drive of the drive means for controlling the cutting amount is controlled such that the torque current detection value of the tool motor becomes a preset reference torque current value when the table is moved a predetermined number of times. Therefore, the work can always be machined with a desired machining amount with high accuracy without measuring the dimensions of the work before and after machining, and the work efficiency and machining efficiency can be improved, and the life of the machining tool can be extended. it can.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a main part of a polishing apparatus according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a main part of a control system of the polishing apparatus shown in FIG.
FIG. 3 is a flowchart schematically showing a processing operation performed by the polishing apparatus shown in FIG. 1;
FIG. 4 is a flowchart showing details of the polishing operation shown in FIG. 3;
FIG. 5 is an external perspective view of a main part of a conventional polishing apparatus.
[Explanation of symbols]
1 gear (work)
2 Wheel gear (machining tool)
3 Table 4 Headstock (work holding part)
5 Tail stock (work holding part)
6 Whetstone mounting head (head part)
7 Wheel gear motor (motor for tool)
Reference Signs List 8 Wheel holding unit 9 Z-axis servo motor 10 Linear scale 11 Controllers 12, 13 Motor drive circuit 15 Torque current detection circuit (torque current detection means)
16. Torque control circuit (torque control means)
17 memory (storage means)

Claims (4)

A table that can reciprocate in a predetermined direction, a work holding unit that detachably holds the work on the table, a working tool that can be engaged with the work held by the work holding unit, and a rotation of the working tool. A head for holding a tool motor to be driven, and driving means for moving the head in a direction intersecting with the direction of movement of the table, wherein the work tool is engaged with the work and the work tool. In the processing apparatus for processing the work by moving the table and the head portion while rotating
Torque current detecting means for detecting the torque current of the tool motor,
Storage means for storing a reference number of movements of the table with respect to the workpiece and a reference torque current value of the tool motor;
Based on a comparison between the torque current detection value detected by the torque current detection means and a reference torque current value stored in the storage means, the torque current detection value is set to be equal to the reference torque current value. Torque control means for controlling the driving of the head unit by the driving means,
A processing apparatus for processing the work by moving the table by a reference number of times of movement stored in the storage means. The processing device according to claim 1, wherein the workpiece is a gear, and the processing tool is a grindstone gear. The processing apparatus according to claim 1, wherein the work is a gear, and the processing tool is a shaving cutter. The processing apparatus according to claim 1, wherein the workpiece is a spline shaft, and the processing tool is a shaving cutter.

Images