JPH04289020A - Automatic setting device for gear grinding machine - Google Patents

Abstract

PURPOSE:To automate a setting work before grinding by oscillatingly driving a gear to be worked by small torque in the stop condition of a grinding wheel, detecting the stop position at contacting the gear with the grinding wheel, and computing the angular position of gear at perfectly engaging with the grinding wheel. CONSTITUTION:An oscillating rotation control means is constituted out of a first encoder 7, an oscillation range target setting means 12, and a positioning control circuit 13, and a torque control means is constituted out of a current control circuit 15, a power amplifier 16, a torque setting means 17, and a torque value converting circuit 22. Further, a grinding wheel advanced position detecting means is out of an encoder 8 of a second motor 6 and a position detecting means 24, a stop detecting means of a gear to be worked is out of an encoder 7 of a first motor 2 and a speed control circuit 14, and a stop position detecting means is out of the encoder 7 and the positioning control circuit 13 respectively constituted. The gear 1 to be ground is oscillatingly rotated, and the grinding wheel 3 is controlled to position in the servolock condition so as to position the bottom center of the wheel 3 on the center line to the gear 1.

Description

Detailed Description of the Invention [0001] [Industrial Application Field] The present invention relates to a gear grinding machine that manufactures gears. ), and relates to an automatic setting device for a gear grinding machine that automatically sets the forward position where the grinding wheel enters the tooth valley of the gear to be machined. [0002] Initial settings for conventional grinding processes have all relied on the hands of skilled workers. In addition, the present inventor has developed an invention in which the shaft of the grinding wheel and the shaft of the gear to be processed are not engaged by a gear mechanism, but both shafts are driven by separate motors, and both motors are controlled by an electronic control device. (unpublished). [0003]According to the prior art, the shaft of the grinding wheel and the shaft of the gear to be machined rotate synchronously to perform adjustment work by a skilled worker at the time of initial setting before the grinding process is performed. Full automation of the process was impossible because of the In addition, gear cutters and grinders are covered with covers such as plastic because the cutting oil is scattered, and since the covers are dirty with the scattered oil, optical recognition methods using video cameras etc. Automatic configuration control is not possible. An object of the present invention is to overcome these difficulties and enable automatic setting work. Means for Solving the Problems The automatic setting device for a gear grinding machine of the present invention includes a first motor that drives the shaft of a gear to be machined in both directions, and a drive torque of the first motor that is set at a predetermined value. a torque control means for controlling the torque to be equal to or less than the above-mentioned value; an oscillating rotation control means for driving the first motor to rotate alternately in both forward and reverse directions within a predetermined range; a means for fixedly holding the grinding wheel; The second gear is displaced in the front-rear direction with respect to the gear to be machined.
a motor, a grinding wheel forward position detection means for detecting the longitudinal position of the grinding wheel, and a torque control means that detects when the shaft of the to-be-processed gear has stopped rotating while the shaft of the to-be-processed gear is oscillatingly rotating. A stop detecting means for detecting, a stop position detecting means for detecting rotational position information of the gear to be machined when the shaft rotation is stopped, first detection information of the stop position detecting means and the forward position of the grinding wheel at that time. The present invention is characterized by having a calculation means for determining the position of the gear to be processed and the forward position of the grinding wheel at the initial stage of the grinding process from the second detection information of the detection means. [Operation] The shaft of the gear to be ground is usually directly connected to the output shaft of the first motor. The shaft of the grinding wheel is also usually directly connected to the output shaft of a separate motor. The first motor and the separate motors are each controlled by independent rotational speed control circuits. The first motor is controlled to a weak rotational torque by the torque control means, and the oscillating rotation control means is controlled so that it vibrates in both forward and reverse directions within a predetermined range of about half the center angle of one of the teeth. Rotate the machining gears alternately. The grinding wheel is rotated by a motor during cutting, but
During the setting work, it is held fixed and is displaced in the front-rear direction by the second motor. When this grinding wheel enters the gear to be ground shallowly and comes into contact with the tooth surface of the rotating gear as shown in Fig. 3, the torque of the first motor is controlled to a weak value. The gear that was oscillating and rotating stops its oscillation. This stop is detected by stop detection means, for example, a rotary encoder, and stop position detection means detects position information at that time. When the rotational direction of the first motor is reversed, the grinding wheel eventually comes into contact with the other opposing tooth surface, the gear stops rocking again, and position information at that time is detected. The center of the tooth valley is calculated from the information on the two stop positions, and the accuracy of calculating the center of the tooth valley is improved by further advancing the grinding wheel and repeating the swinging and stopping. Finally, when both surfaces of the grinding wheel are in contact with the tooth surfaces, and the grinding wheel penetrates the deepest, the automatic setting operation according to the present invention ends, and the grinding operation starts. [Example] FIG. 1 shows an external view of a gear grinding machine. The gear to be ground 1 is directly driven by a first motor 2 , and the grinding wheel 3 is directly driven by a third motor 4 . Further, the holding base 5 of the grinding wheel 3 can be moved forward and backward relative to the gear to be ground 1 by the second motor 6 and the feed screw. The first motor 2 is driven both clockwise and counterclockwise, thereby making it possible to swing the gear to be processed within a predetermined angular range. first and second motors 2, 6
Both are driven by an inverter AC power supply,
By controlling the conversion frequency of the inverter, its rotation speed can be varied continuously over a wide range.
In addition, it is possible to control the motor into a so-called servo lock state, in which the rotating magnetic field is stopped and the motor output shaft is stopped with a large torque. DD motors (dilate drive motors) for factory automation that have recently been put into practical use, especially low-speed DD motors that perform rotary feed drive,
Since low speed rotation control is possible, pulsating torque is low, and high resolution positioning control is possible, it is suitable for the first and second motors of the present invention. When using a motor with a built-in encoder (seconds or less), there is no need to add an encoder as a position sensor (Nikkei Mechanical November 26, 1990 issue, P. 108 to P. 114). FIG. 2 shows a block diagram of an embodiment of the control system of the present invention. The first motor drive control circuit section 11 generates a positioning command signal from a swing signal generating means 12 that generates, for example, a sine wave signal serving as a target value for the swing rotation, and the swing signal and a feedback signal S1 of the rotary encoder 7. A positioning control circuit 13 that outputs a positioning command signal, a speed control circuit 14 that obtains a speed signal by differentiating the positioning command signal and lowers the speed when the deviation of the position feedback value from the target value is small, and a torque value setting means 17. The current control circuit 15 detects the deviation of the driving torque TM fed back from the next-stage power amplifier 16 via the torque value conversion circuit 22 with respect to the weak torque value TR, and controls the torque to a predetermined weak torque. It is composed of a power amplifier 16 that rotationally drives the first motor in the rotational direction, speed, and torque value commanded by each control circuit. The drive control circuit section of the second motor 6 that drives the grinding wheel holder 5 in the longitudinal direction is controlled by a positioning control circuit 18 and a speed control circuit 19, and its feedback signal S2 is sent by a rotary encoder 8. The calculated value of this pulse signal becomes the forward position signal of the grinding wheel. The third motor 4 that rotates or servo-locks the grinding wheel 3 is controlled by a positioning control circuit 20 and a speed control circuit 21, and its feedback signal S3
is inputted to the positioning control circuit 20 to control the servo lock state, and is also inputted to the drive control circuit section 11 of the first motor described above to control the rotational speed of the first motor during the grinding process. This is used to control the rotational speed of the motor to a predetermined ratio of 1/N. This is essential when grinding the gear to be machined after automatic setting according to the invention. This rotation ratio control means and the like can be implemented by software of the central numerical controller CNC 23, and the CNC 23 can also serve as the functions of other control circuits. [0010] The first encoder 7 in this embodiment,
Oscillation range target setting means 12 and positioning control circuit 1
3 constitutes the swing rotation control means of the present invention, which includes a current control circuit 15, a power amplifier 16, and a torque value setting means 17.
and the torque value conversion circuit 22 constitute the torque control means of the present invention. Also, the encoder 8 of the second motor 6
, the position detection means 24 constitutes a grinding wheel forward position detection means, the encoder 7 of the first motor 2 and the speed control circuit 14 constitute stop detection means for the gear to be machined, and the encoder 7 and the positioning control circuit 13 constitute a stop detection means. It constitutes a position detection means. The operation of the embodiment of the present invention will be explained with reference to FIG. The gear to be ground 1 swings and rotates clockwise and counterclockwise, and the grinding wheel 3 is positioned in a servo-locked state so that the center of the valley of the grinding wheel is located on the center line C between the gears to be ground 1. It can be displaced in the front-back direction along the center line C while being moved. If the stop position detection signal when the gear 1 rotates counterclockwise (positive direction) is θCCW, and the stop position detection signal when the gear 1 rotates clockwise (negative direction) is θCW, then the teeth of the gear 1 The positioning command signal θO for setting the center of the mountain on the center line C is as follows: θ0 = (θCW-θCCW)/2 By repeating the operation several times, θ0, θCW
, θCCW become substantially 0, and the grinding wheel 3 and gear 1 come into close contact. In this state, the automatic setting process according to the present invention ends. When the gear to be machined is a helical gear, the present invention can be similarly applied by simply tilting the axis of the gear to be machined by the helical angle α. Note that the work of attaching and detaching the gear to be machined can be easily carried out using conventionally known techniques as they are. [0013]According to the present invention, it is possible to automate the positioning work of the gear to be ground and the grinding wheel before the start of grinding, which has been considered extremely difficult in the past. In addition, there is no gear mechanism that engages the shaft of the gear to be ground and the shaft of the grinding wheel as in the past.
Since both shafts are directly driven by their respective motors, there are no production errors due to play in the gear mechanism, and extremely high precision grinding can be performed.

[Brief explanation of the drawing]

FIG. 1 is a front view of a mechanical part of an embodiment of the present invention.

FIG. 2 is a block diagram of a control system according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of the operation of the present invention.

[Explanation of symbols]

1...Gear to be ground 2...First motor 3. Grinding wheel 5. Grinding wheel holding stand 6...Second motor

Claims (1)

[Claims] 1. A first motor that drives the shaft of a gear to be machined in both directions; a torque control means that controls the driving torque of the first motor to a predetermined value or less; an oscillating rotation control means for rotating the grinding wheel alternately in both forward and reverse directions; a means for fixing and holding the grinding wheel; a second motor for displacing the grinding wheel in the front-rear direction with respect to the to-be-processed gear; a grinding wheel forward position detection means for detecting the longitudinal position of the wheel; and a stop detection means for detecting that the shaft rotation of the workpiece gear is stopped by the torque control means while the shaft of the workpiece gear is oscillatingly rotating. , a stop position detection means for detecting rotational position information of the gear to be machined when the rotation of the shaft is stopped, first detection information of the stop position detection means and second detection information of the grinding wheel forward position detection means at that time. An automatic setting device for a gear grinding machine, which has a calculation means for determining the initial position of the processed gear and the forward position of the grinding wheel from the detected information.