JPH07164246A - Tooth shape finishing device - Google Patents

Abstract

PURPOSE:To provide a tooth shape finishing device which can prevent the mis-detection of a no-backlash position caused by the time change of the drive control system of a work. CONSTITUTION:A gain adjuster 30 is put in connection between a amplitude setter 26 and a servo-amplifier 27 and the amplitude of normal/reverse rotation of a work drive motor 13 during a no-backlash position detection action is measured and a feedback control is carried out so that a measured amplitude can be a set value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a tooth profile finishing apparatus for finishing and shaping a tooth profile previously formed on a work by means of a grindstone rotating relative to the work.

[0002]

2. Description of the Related Art There are a large number of gear parts such as transmission gears and steering gears as parts constituting automobiles.

Such gear parts for automobiles are required to be finished with high precision and to have high work efficiency in order to cope with mass production. Therefore, in general, gear parts are finished by shaving after pre-processing to form the tooth profile with a hob or pinion cutter in advance, and then final finishing shaping of the tooth profile by honing after heat treatment. There is.

As a tooth profile finishing device for finishing and shaping a tooth profile of a workpiece by honing, devices such as those shown in FIGS. 2 and 3 have been devised conventionally. This device is provided with a holding means 1 for holding the head side end of the work W.
And a holding means 2 for holding the tail side end portion, and a grindstone base unit 4 equipped with a grindstone 3, and a workpiece W having a gear G formed in advance is rotated via the holding means 1, 2. The work W is rotatably held, and the work W is relatively rotated by relatively rotating the grindstone 3 in which the tooth (hereinafter, grindstone tooth) having a shape corresponding to the tooth 5 of the gear G (hereinafter, work tooth) is shaped. Honing is performed to finish and shape the work teeth 5.

FIG. 2 is an external view of such an apparatus. As can be seen from the figure, both the holding means 1 and 2 are installed on a bed 6. Further, this apparatus is provided with a rotation axis C of the work W, a rotation axis S of the grindstone 3, a cutting axis Z of the grindstone 3, a work oscillation axis X, and a helical angle axis Y. A predetermined work is performed by appropriately driving the shaft of. In addition, "7" in the figure is an operation panel.

FIG. 3 shows a drive system for the work W and the grindstone 3. The holding means 1 on the head side incorporates therein a shaft 9 which is rotatably held via a bearing 8. A center 10 is attached to one end of the shaft 9 to support the center of rotation of the end of the work W on the head side. A work drive motor 13 is connected to the other end of the shaft 9 via an electromagnetic clutch 11 and a speed reducer 12. A servo motor is used as the work drive motor 13. The driving force of the work drive motor 13 is selectively transmitted to the work W by turning on and off the electromagnetic clutch 11, and the work W is driven around the work rotation axis C. An encoder 14 is attached to the work drive motor 13. With this encoder 14, the work drive motor 1
3 position detection is performed.

The tail side holding means 2 has a center 15 for supporting the center of rotation of the tail end of the work W. The center 15 rotates together with the work W, and the rotation position is detected by an encoder 17 connected via a belt 16. The amplitude of the work W is measured by this encoder 17. The holding means 2 also includes a mechanism (not shown) for moving the center 10 forward and backward with respect to the work W.

Work rests 18, 1 for holding both ends of the work W when the work W is carried in and out of the apparatus.
9 are attached to the holding means 1 and 2, respectively. Further, the work W supported by both the centers 10 and 15
In order to index the work tooth 5 of the above, a proximity sensor 20 for detecting the position of the tooth is attached to the work rest 18.

The grindstone base unit 4 has an internal tooth type grindstone 3 having a ring shape and rotatably mounted, and a grindstone driving motor 21 for rotating the grindstone 3 around a grindstone rotation axis S.
And have. The grindstone 3 is fixed to the inner peripheral surface of the pulley 22 via a grindstone retainer (not shown). A servo motor is used as the grindstone drive motor 21. An encoder 22 for indexing the grindstone rotation axis S is attached to the grindstone drive motor 21. Further, in order to fix the grindstone 3 to the grindstone base unit 4, a locate pin 23 for fixing the grindstone is provided in the grindstone base unit 4. Although not shown in FIG. 4, a cutting shaft for moving the grinding wheel head unit 4 forward and backward with respect to the work W in the direction of the grinding wheel cutting axis Z in order to engage and disengage the grinding wheel tooth 3a with the work tooth 5. A motor is provided. As the cutting shaft motor, a servo motor is used like the other motors 13 and 21.

FIG. 4 shows a meshing state between the gear G of the work W and the grindstone 3. When performing the honing process, the grindstone base unit 4 is ground and fed by a cutting shaft motor (not shown) while the grindstone drive motor 21 is rotated for grinding. As a result, the grindstone 3 includes the work tooth 5 and the grindstone tooth 3a.
Are to be driven to rotate about the grindstone rotation axis S at a constant speed while contacting with each other under a predetermined pressing force, and the work teeth 5 are ground by the grindstone teeth 3a as the grindstone 3 rotates and finally The finishing shaping will be performed. At this time,
The work W supported by both the centers 10 and 15 rotates while being driven by the rotation of the grindstone 3.

By the way, in order to finish the work teeth 5 with high accuracy by honing, the work teeth 5 and the grindstone teeth 3 are used.
It is important to grind while a and a are brought into contact with each other in the absence of so-called backlash. If work W
If the meshing relationship between the grindstone and the grindstone 3 is not perfect, an unground portion remains. Therefore, it is necessary to set the work tooth 5 and the grindstone tooth 3a in a positional relationship in which there is no backlash (hereinafter referred to as a no backlash position) before starting the grinding for the honing process.

Therefore, in the above-described apparatus, the no-backlash position is detected as follows, and the work tooth 5 and the grindstone tooth 3a are meshed with each other without backlash.

That is, first, the work W is supported by the holding means 1 and 2, the work teeth 5 and the grindstone teeth 3a are lightly meshed with each other, and the grindstone drive motor 21 is fixed by a brake so that the grindstone 4 does not move. To do. Then, the electromagnetic clutch 11
Is turned on, a sine wave command is given to the work drive motor 13 to reverse the work drive motor 13 in the normal direction. Then, the work W is forcibly driven to rotate around the work rotation axis C by the driving force of the work drive motor 13. FIG. 5 is a block diagram of the drive control system. Sine wave generated by the sine wave oscillator 25 (for example, 8 to 10 Hz)
Is amplified by the amplitude setter 26 and then supplied to the work drive motor 13 through the servo amplifier 27. The amplitude setter 26 is an amplifier for sufficiently rotating the work W in the forward and reverse directions with the output of the sine wave oscillator 25, and its gain is set in advance by the user to an appropriate value.

On the other hand, while the work drive motor 13 is rotated in the normal direction and the work W is vibrated in the rotation direction,
A notch shaft motor (not shown) is driven to drive the grinding wheel head unit 4
Is advanced in the direction of the grinding wheel cutting axis Z to make a cut.
Then, the rotation position of the work W is detected in real time by the encoder, and the amplitude of the normal rotation reversal motion (vibration) of the work W is obtained (amplitude = maximum value−minimum value).

FIG. 6 shows the position of the cutting axis (Z axis) and the work W.
Shows the relationship with the vibration of. In the figure, when the backlash between the work tooth 5 and the grindstone tooth 3a is large and the work W and the grindstone 3 are separated from each other, the work W vibrates with the maximum amplitude Bmax, and from this state, further cutting is performed. , The work W and the grindstone 3 start to hit, the grindstone 3
Since the backlash decreases as a approaches the work teeth 5, the vibration amplitude of the work W gradually decreases. Therefore, when the measured amplitude value of the work W becomes less than or equal to a predetermined value B0 corresponding to the amplitude at the no-backlash position L0 measured in advance, the cutting is stopped and the positioning of the work W and the grindstone 3 is completed. . As a result, the work tooth 5 and the grindstone tooth 3a come into contact with each other without backlash.

Although the case where the grindstone 3 is provided so as to be movable toward and away from the work W is shown here, the present invention is not limited to this, and the work W is provided so as to be movable toward and away from the grindstone 3. Of course, it is also good.

[0017]

However, in such a conventional tooth profile finishing device, as shown in FIG. 7, the amplitude of the work W is set to the predetermined value before the original no backlash position is reached. It becomes B0, which may cause false detection of the no-backlash position. The cause is that the drive control system shown in FIG. 5 reduces the total gain such as the gain of the servo amplifier and the gain of the command board due to the change of the environmental temperature, and therefore the amplitude of the forward / reverse movement of the work drive motor 13 decreases. Can be considered. There is a problem that such a phenomenon cannot be dealt with by the conventional drive control system based on feedforward control.

The present invention has been made in order to solve the problems associated with the above-mentioned prior art, and provides a tooth profile finishing device capable of preventing erroneous detection of the no-backlash position due to the time change of the work drive control system. The purpose is to provide.

[0019]

SUMMARY OF THE INVENTION To achieve the above object, the present invention rotatably holds a work having a tooth profile formed in advance and uses a grindstone shaped into a shape corresponding to the tooth profile of the work. Provided so that they can move toward and away from each other relatively toward the teeth, when the work and the grindstone are relatively rotated to perform honing to finish and shape the tooth profile of the work, the grindstone is fixed in advance. Make a cut while reversing the work in the normal state, measure the amplitude of the normal reversal movement of the work at that time, the measured amplitude is a state without backlash between the tooth of the work and the tooth of the grindstone In the tooth profile finishing apparatus, the tooth of the workpiece and the tooth of the grindstone are moved relatively close to each other until the amplitude becomes less than or equal to Signal creating means for creating a command signal for reversing the work driving means in the normal direction, amplitude measuring means for measuring the amplitude of the normal reversing movement of the work driving means, and amplitude comparing means for comparing the measured amplitude with a set value. And output control means for controlling the output of the signal generating means so that the amplitude of the work driving means becomes the set value based on the comparison result.

[0020]

According to the present invention having such a configuration, in order to detect the position where there is no backlash between the tooth of the work and the tooth of the grindstone, the work drive means is normally rotated by the command signal from the signal generating means. Upon reversing, the amplitude measuring means measures the amplitude of the normal / reversal movement of the work driving means, and the amplitude comparing means compares the measured amplitude with the set value. Based on the result of this comparison, the output control means controls the output of the signal generating means so that the amplitude of the work driving means becomes the set value. As a result, the amplitude of the normal rotation reversal movement of the work drive means is always maintained constant, and the amplitude of the normal rotation reversal movement of the work when the workpiece is cut while reversing the normal rotation with the grindstone fixed. Is prevented from being unduly increased or decreased, so that it is possible to prevent erroneous detection of the state without backlash.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a drive control system according to an embodiment of the present invention. In FIG. 1, the same members as those in FIG. 5 are designated by the same reference numerals.

The tooth profile finishing apparatus of the present invention is an improvement of the above-mentioned conventional corrugated finishing apparatus. In this embodiment, the basic structure of the apparatus is the same as that of the conventional apparatus shown in FIGS. Since they are the same and the principle of detecting the no-backlash position between the work tooth 5 and the grindstone tooth 3a is also the same, a description thereof will be omitted. Only the parts different from the above-mentioned conventional device will be described below.

Unlike the conventional drive control system (see FIG. 5), the drive control system of the work drive motor 13 according to the present embodiment measures the amplitude of the forward / reverse movement of the work drive motor 13 and performs feedback control. Is configured.
That is, a sine wave oscillator 25 that generates a sine wave (for example, 8 to 10 Hz), an amplitude setter 26 that amplifies the output from the sine wave oscillator 25 to the extent that the work W can be sufficiently rotated normally and inverted, and a gain. The gain adjuster 30 for changing the (gain) to set the value to obtain a good result, the servo amplifier 27, and the work drive motor (servo motor) 13
The encoder 14 attached to the work drive motor 13, the amplitude detector 31 for detecting the amplitude of the forward / reverse movement of the work drive motor 13 based on the position signal from the encoder 14, and the amplitude detector 31. And a comparator 32 for comparing the detected amplitude with a set value. The gain of the amplitude setter 26 is set to an appropriate value in advance by the user, as described above.

The gain adjuster 30 has a function of automatically adjusting the gain according to the comparison result between the measured amplitude value and the set value, and the initial value is set to 1. And
After that, if the measured value is smaller than the set value (measured value <set value), the gain is increased, while if the measured value is larger than the set value (measured value> set value), the gain is reduced. There is.

The amplitude detector 31 detects the amplitude of the forward / reverse movement of the work drive motor 13 based on the position signal from the encoder 14, the principle of which is the work W described above.
This is the same as the method of obtaining the amplitude of the normal reversal motion (vibration) of. That is, the position data from the encoder 14 is sampled for one cycle to obtain the maximum value and the minimum value,
The amplitude of the forward / reverse movement of the work drive motor 13 is obtained by substituting it into the following equation. Amplitude = maximum value−minimum value This processing is performed because there is always a minimum value and a maximum value for determining the amplitude of the forward / reverse movement of the work drive motor 13 in one cycle.

The work driving means is the work driving motor 13, and the signal generating means is the sine wave oscillator 25 and the amplitude setting device 2.
6. The amplitude measuring means includes an encoder 14 and an amplitude detector 31,
The amplitude comparison means is composed of a comparator 32, and the output control means is composed of a gain adjuster 30.

Next, the operation will be described. In the feedback control system configured as above, the sine wave oscillator 25
The sine wave command from the amplitude setter 26, the gain adjuster 3
0, and after being appropriately amplified through the servo amplifier 27, the work drive motor 13 is supplied to the work drive motor 13 and receives the signal, and the work drive motor 13 is normally rotated and inverted at a predetermined cycle.
The amplitude of the forward / reverse movement of the work drive motor 13 at this time is measured by the encoder 14 and the amplitude detector 31, and is sent to the comparator 32 as a feedback signal. Comparator 3
2 is a gain adjuster that compares the measured amplitude value with a preset setting value to generate a control signal necessary to match the amplitude of the forward / reverse movement of the work drive motor 13 with the set value. Send to 30. That is, if the measured value is smaller than the set value (measured value <set value), the gain is increased, and if the measured value is larger than the set value (measured value> set value)
A command is issued to the gain adjuster 30 to reduce the gain. According to this command, the gain adjuster 30 changes the gain to an appropriate value so that the measured amplitude value becomes the set value.
As a result, the work drive motor 13 is always rotated in the normal direction at a predetermined amplitude.

Therefore, according to the present embodiment, the drive control system of the work drive motor 13 is configured as a feedback control system, and the servo amplifier 27 is constantly comparing the amplitude of the forward / reverse movement of the work drive motor 13 with the set value. Since the command is adjusted, the amplitude of the work drive motor 13 is always maintained at the set value. Therefore, even when the drive control system changes with time when the work W is cut while reversing the work W with the grindstone 3 fixed, the amplitude of the normal reversing motion of the work W is affected by the change. Does not increase / decrease, so that the no backlash position is not erroneously detected due to the time change of the drive control system of the work drive motor 13, and the reliability of the no backlash position detection is improved. .

[0029]

As described above, according to the present invention, the amplitude of the forward / reverse movement of the work driving means during the operation for detecting the state without backlash is measured, and the measured amplitude becomes the set value. Since I tried to perform feedback control,
Since the amplitude of the forward / reverse movement of the work driving means is always maintained at the set value, it is possible to prevent erroneous detection due to the time change of the drive control system of the work driving means, and there is no backlash. The reliability of the operation of detecting the state is improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a drive control system of a work drive motor according to an embodiment of the present invention.

[Fig. 2] External view of tooth profile finishing device

FIG. 3 is a schematic diagram of a drive system for a work and a grindstone in the apparatus of FIG.

FIG. 4 is a view showing a meshing state between a work and a grindstone.

FIG. 5 is a block diagram of a drive control system of a conventional work drive motor.

FIG. 6 is a diagram for explaining a detection principle of a state without backlash.

FIG. 7 is a diagram for explaining problems of the conventional technology.

[Explanation of symbols]

 3 ... Whetstone 3a ... Whetstone tooth 4 ... Whetstone base unit 5 ... Work tooth 13 ... Work drive motor (work drive means) 14 ... Encoder (amplitude measurement means) 25 ... Sine wave oscillator (signal creation means) 26 ... Amplitude setter ( Signal creating means) 27 ... Servo amplifier 30 ... Gain adjuster (output control means) 31 ... Amplitude detector (amplitude measuring means) 32 ... Comparator (amplitude comparing means) W ... Work G ... Gear

Claims (1)

[Claims] 1. A work having a tooth profile formed therein is rotatably held, and a grindstone shaped into a shape corresponding to the tooth profile is provided so as to be relatively movable toward and away from the tooth of the work. When performing the honing process by relatively rotating the work and the grindstone to finish and shape the tooth profile of the work, in advance, while making a cut while inverting the work in the state in which the grindstone is fixed, the work is performed at that time. The amplitude of the normal rotation reversal movement of the work is measured, until the measured amplitude is equal to or less than the amplitude in a state without backlash between the tooth of the work and the tooth of the grindstone. In a tooth profile finishing device in which a tooth is relatively moved, a work driving means for rotationally driving the work and a command signal for reversing the work driving means in a normal direction are created. A signal generating means, an amplitude measuring means for measuring the amplitude of the forward / reverse movement of the work driving means, an amplitude comparing means for comparing the measured amplitude with a set value, and based on the comparison result, the work driving means A tooth profile finishing device, comprising: output control means for controlling the output of the signal generating means so that the amplitude becomes the set value.