JPS6121775B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a helical gear processing device.

In order to machine a workpiece gear (hereinafter simply referred to as a workpiece) over its entire face width, the workpiece must be moved in the axial direction, or traversed, but if the workpiece is a helical gear, Since the thread is twisted, the synchronous operation state, which is performed depending on the tooth number ratio of the grinding wheel and the workpiece, must be changed by an appropriate amount depending on the traverse amount. Additionally, the grinding resistance received from the workpiece's grinding wheel differs in magnitude and direction between the center and both ends of the workpiece in the face width direction, which tends to result in poor tooth trace accuracy, and there are also errors in tooth trace accuracy due to the characteristics of the machine. , To fix this, we need to change the synchronous operation accordingly as before.

Therefore, in conventional devices, the workpiece is rotated by a workpiece spindle drive motor via a differential gear and a reduction gear train, and the gear ratio of the differential gear is changed depending on the direction and amount of traverse of the workpiece.
However, when machining helical gears with different helix angles, the gears must be replaced to change the tooth ratio of the differential gear, which requires a lot of effort and time, and requires a high precision gear. When using this method, there were disadvantages such as being expensive and making it difficult to obtain a highly accurate product.

Another conventional device has a separate circuit for synchronously rotating the workpiece spindle and the grinding wheel spindle, and a circuit for generating additional pulses for the helical gear. However, since the pulse interval of the workpiece changes rapidly due to this adjustment, there are disadvantages such as having an adverse effect on the servo system (for example, the gain cannot be increased, machining accuracy decreases, etc.). It was hot.

The present invention aims to eliminate the above-mentioned disadvantages of conventional devices, and includes a first pulse generator that outputs pulses at a frequency corresponding to the rotation of a tool;
It is equipped with a second pulse generator that outputs pulses with a frequency corresponding to the rotation of the workpiece, and compares the output pulses of the first pulse generator with the output pulses of the second pulse generator, and adjusts the workpiece spindle according to the result. In a gear processing device that controls the speed of the workpiece and synchronizes the rotation of the workpiece with the rotation of the tool, a rotary shaft is connected to the workpiece spindle, the outer cylinder part is rotatable, and a pulse is output at a frequency corresponding to the rotation of the rotary shaft. a second pulse generator, a third pulse generator that generates pulses in response to the relative movement amount between the workpiece and the grinding wheel, and an external pulse generator that generates pulses according to the output pulses of the third pulse generator. The invention is characterized by providing means for rotating the cylindrical portion and increasing or decreasing the frequency of the output pulse of the second pulse generator from the frequency corresponding to the rotation of the workpiece in accordance with the movement of the workpiece or the grindstone in the axial direction. .

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view of the apparatus of the present invention, and FIG. 2 is a plan view of the work drive section thereof. In the drawings, reference numeral 1 denotes a bed, on which a column 2 and a cutting table 3 driven by a cutting motor 4 are provided. Cutting table 3
A traverse table 5 that slides in a direction perpendicular to the table 5 to move the position of the workpiece to be processed and a traverse motor 6 that drives the traverse motor 6 are disposed above the table 5, and a work spindle unit 7 is disposed on the table 5. The work spindle unit 7 includes a work spindle motor 8, a gear 10 provided on its drive shaft 9 by the motor 8, a work spindle 13 driven by the gear 11 meshing with the gear 11, and a clutch 12, and a work 14. a pulse generator 15 connected to the drive shaft 9;
A gear 1 integrated with the rotation support shaft is attached to the outer cylindrical portion 15A of the
6 and a differential motor 18 connected via a gear 17 that meshes with the differential motor 18, and a pulse generator 19 connected to the motor shaft. On the other hand, on the column 2 is a turning table 20 which is located in a vertical plane perpendicular to the cutting direction and whose center of rotation is at the same height as the axis of the work spindle 13. There is a shift table 21 that moves the grindstone 24 minute by little in the direction of the grindstone spindle 23, and above it there is a grindstone spindle motor 22, a grindstone spindle 23 driven by this (Fig. 3), and a grindstone 2.
4 and a grindstone spindle unit 26 including a pulse generator 25 were arranged in each case.

FIG. 3 is a block diagram showing the circuit of the device;
Reference numeral 27 denotes a pulse selection output device, which includes a memory 27-1 for storing pulses to be selected and output from among the output pulses of the pulse generator 25;
It consists of a shift register 27-2 driven by the output pulses of the pulse generator 25, and a computer having a CPU 27-3 for storing the pulses to be selected and output in the memory 27-1.
When the output pulse is input to the shift register 27-2, the pulses stored in the memory 27-2 to be selected and output are read out via an AND gate (not shown) in synchronization with the output pulse. Reference numeral 28 denotes a frequency-voltage converter, which is interposed between the pulse selection output device 27 and the adder 29 and connected in parallel with the comparator 30 and the DA converter 31. 32
is an amplifier, and has an amplification factor that amplifies the output of the adder 29 to a size that allows the work spindle motor 8 to rotate under the conditions described later. A pulse generator 33 is driven by the traverse motor 6 and outputs pulses in accordance with its rotation, and its output is connected to the pulse selection output device 34. This has the same configuration as the pulse selection output device 27, and the memory 34
-1, shift register 34-2, CPU34-3
It consists of a computer with The output of this device was connected via a comparison detector 35, a DA converter 36, a polarity converter 37 and an amplifier 38 to a differential motor 18, for example a DC motor.

Next, its operation will be explained.

The grindstone 24 and the pulse generator 25 are rotated by the grindstone spindle motor 22, and the pulse generator 2
5 outputs _n25 pulses per second.

n ₂₅ = N ₂₄ · P ₂₅ ... [1] However, N ₂₅ is the number of revolutions per second of the grinding wheel 24, and P ₂₅ is the number of output pulses per revolution of the pulse generator 25.

On the other hand, the workpiece 14 and the pulse generator 15 are rotated by the workpiece spindle motor 8, and the pulse generator 15 outputs _n25 pulses per second.

n ₁₅ = N ₁₄ · P ₁₅ · Z ₁₁ /Z ₁₀ ... [2] However, N ₁₄ is the number of revolutions per second of the workpiece 14, P ₁₅ is the number of output pulses per revolution of the pulse generator 15,
Z ₁₀ and Z ₁₁ are the numbers of teeth of gears 10 and 11.

When the rotation of the workpiece 14 is synchronized with the rotation of the grindstone 24 (Z ₂₄ · N ₂₄ = Z ₁₄ · N ₁₄ ... [3], however, Z ₁₄
is the number of teeth of the workpiece 14, and _Z24 is the number of threads of the grindstone 24. ),
What is the number of output pulses per second n ₂₅ of the pulse generator 25 and the number of output pulses per second n ₁₅ of the pulse generator 15? n ₁₅ = (P ₁₅ /P ₂₅・Z ₁₁ /Z ₁₀・Z ₂₄ /
Z ₁₄ )・n ₂₅ ...[4] The relationship is as follows.

As is clear from this formula [3], the number of output pulses per second n ₁₅ of the pulse generator 15 is changed to the number of output pulses per second n ₂₅ of the pulse generator 25 by a coefficient K=(P ₁₅ /P ₂₅・Z ₁₁ /Z ₁₀・Z ₂₄ /Z
₁₄ ) If the rotational speed of the workpiece 14 is controlled to be equal to the value multiplied by . In other words, work 14
can be operated synchronously with respect to frequency 4.

Until the rotation of the workpiece 14 is synchronized with the rotation of the grindstone 24, the workpiece 14 is moved to a predetermined position close to the grindstone 24 by the cutting table 3 and moved to the traverse start position by the traverse table 5. The rotation of the workpiece 14 is the grindstone 24
When synchronized with the rotation of the workpiece 14 and the grinding wheel 2
After confirming by some means that the teeth of No. 4 are in phase, advance the cutting table 3 and mesh them together.
Next, the traverse motor 6 is driven to start traversing the workpiece 14 using the traverse table 5. When the above-mentioned means is not used, the workpiece 14 and the grindstone 24 are engaged with each other in a stopped state, and then rotated to a synchronous speed to start traversing.

If the workpiece gear is a spur gear, workpiece 1
4, the workpiece 14 may be rotated at the above synchronous speed, but in the case of a helical gear, the rotation of the workpiece 14 should be adjusted to ensure proper traversal as described above. is changed from the synchronous operation state by an appropriate amount depending on the traverse.

That is, when traversing the workpiece 14 from one direction to the other, the rotational speed of the spindle 13 is made faster or slower than the rotational speed during the synchronous operation,
When traversing in one direction from another direction, the rotation speed is slowed down or fast in the opposite direction.

In FIG. 3, pulses with a frequency corresponding to the rotational speed of the grinding wheel 24 outputted from the pulse generator 25 are sent to a shift register 27 of a pulse selection output device 27.
-2. Each address of the memory 27-1 corresponds to each output pulse of the pulse generator 25, and each address corresponding to a value obtained by converting 1/K ₁ ·n (n=1, 2, 3,...) into an integer is assigned a level ". 1" and "0" to other addresses by operating the keys on the computer and installing that CPU2.
7-3, in response to the shift operation of the shift register 27-1, the stored content "1" at the address 1/ _K1.n (integer value) is changed to the other address by the output of the shift register 27-1. The stored content "0" of is successively outputted via the AND gate at the time of the output pulse corresponding to that number. Thus, the pulse selection output device 27
, one pulse for every 1/K ₁ ·n (integer value) output pulse of the pulse generator 25, therefore 1
Pulses of K ₁・n ₂₅ are output per second.

This pulse is converted by a frequency-voltage converter 28 into an analog voltage having a magnitude corresponding to the pulse frequency, and this voltage passes through an adder 29, is amplified by an amplifier 32, and is applied to the work spindle motor 8 to drive it. Since the amplification factor of the amplifier 32 is set to a predetermined value, the number of rotations N ₁₄ of the workpiece 14 driven by the motor 8 is expressed by the formula [3], and the number of output pulses per second n ₁₅ of the pulse generator 15 is expressed by the formula [3]. 4] The value follows the formula.

When the load on the work spindle motor 8 increases and its rotational speed decreases by, for example, one pulse of the output pulse of the pulse generator 15, the pulse equivalent to that one pulse is output from the comparator 30 and is converted The signal is converted into an analog quantity by the converter 31, and added to the output of the frequency-voltage converter 28 by the adder 29. Therefore, this added voltage is applied to the work spindle motor 8, raising the motor 8 to a value that satisfies equation [3].

On the other hand, the traverse motor 6 drives the traverse table 5 to traverse the workpiece 14, and also drives the pulse generator 33, which outputs the number of pulses corresponding to the amount of traverse. This pulse is input to the pulse selection output device 34, and by the shift operation of the shift register 34-2, the pulse to be selected and output from the memory 34-1 is
It is output in synchronization with the output pulse of the pulse generator 33 via an AND gate. Thus, this pulse passes through the comparator 35, the DA converter 36, the polarity converter 37, and the amplifier 38, and is applied as an analog voltage to the differential motor 18 to drive it, and is input to the comparator 35. In other words, the outer cylindrical portion 15A of the pulse generator 15 is rotated by a predetermined angle corresponding to the amount of traverse of the workpiece 14 until the number of output pulses of the pulse generator 19 matches the number of output pulses of the pulse selection output device 34. This is the pulse generator 15
This is equivalent to rotating the drive shaft 9 by a predetermined angle in the direction opposite to the rotation direction of the outer cylinder part 15A, so the output pulse frequency of the pulse generator 15 increases or decreases depending on the rotation direction of the outer cylinder part 15A. However, the workpiece 14 apparently changes from a state of synchronous operation to a state of constant advance or lag. This lead or lag state is determined by the output pulses of the pulse generator 15 being input to the comparator 30 and compared with the output pulses of the pulse sorting device 27. Before long, the workpiece 14 will be in an apparently synchronous operation state. That is, the workpiece 14 actually moves slower or faster than in the synchronous operation state.

When the traverse of the workpiece 14 is reversed, the polarity converter 37 applies a voltage of opposite polarity in synchronization with the power supply voltage of the traverse motor 6.
Since an analog voltage of opposite polarity is applied to 8, the differential motor 18 is reversed and, contrary to the previous traverse, the workpiece 14 becomes faster or slower than in the synchronous operating condition. Now, the number of pulses per 1 mm of traverse amount is P ₃₃ ,
The rotation angle δ degrees per pulse of the differential motor 18, the number of teeth of the gears 16 and 17 are respectively Z ₁₆ , Z ₁₇ , and the gear 1.
If the PCD of 4 is d ₁₄ mm and the torsion angle is β ₁₄ angle,
The center angle of the amount of twist for a workpiece width of 1 mm is 360·tanβ ₁₄ /πd ₁₄ (degrees), and the corresponding rotation angle of the pulse generator 15 is 360·tanβ ₁₄ /πd ₁₄ ·Z _1
1 /Z ₁₀ (degrees), therefore the rotation angle θ ₁₈ of the differential motor 18 is θ ₁₈ =360・tanβ ₁₄ /πd ₁₄・Z ₁₁ /Z
₁₀・Z ₁₆ /Z ₁₇ (degrees), and the number of pulses P ₁₈ to rotate the differential motor 18 by θ ₁₈ degrees is P ₁₈ = θ ₁₈ /δ In other words, the number of frequency pulses P ₃₃ of the pulse generator 33
The coefficient K ₂ to obtain the necessary pulse P ₁₈ is K ₂ =P ₁₈ /P ₃₃ =360・tanβ ₁₄ Z ₁₁・
Z ₁₆ /π·δ·d ₁₄ Z ₁₀ ·Z ₁₇ P ₃₃ This coefficient K ₂ is set to K ₂ 1 and is defined by the pulse selection output device 34. This coefficient K ₂ is set in the same manner as in the case of the pulse selection output device 27. The capacity of the memory 34-1 of the pulse selection output device 34 must be determined in consideration of the allowable tooth trace error.

Incidentally, the differential motor 18 may be a pulse motor, and in this case, the comparison calculation section 35, the DA converter 36, and the pulse generator 19 can be omitted.

As described above, the present invention includes the first and second pulse generators that output frequencies corresponding to the rotations of the tool and the workpiece, respectively, and compares the output pulses of the first and second pulse generators. In a gear processing device that controls the speed of the work spindle according to the results and synchronizes the rotation of the workpiece with the rotation of the tool, the rotary shaft is connected to the work spindle and the outer cylinder is rotatable to correspond to the rotation of the rotary shaft. a second pulse generator that outputs pulses at a frequency that corresponds to the relative movement of the workpiece and the grindstone; Means is provided for rotating the outer cylindrical portion of the second pulse generator to increase or decrease the frequency of the output pulse of the second pulse generator from the frequency corresponding to the rotation of the workpiece in accordance with the movement of the workpiece in the axial direction. Therefore, when machining multiple types of helical gears with different helical angles, unlike conventional methods, it does not take much time and effort, there is no need to prepare expensive replacement gears, and the synchronous pulse train is smooth. Because of this, unlike other conventional devices, there is no adverse effect on the servo system, and there are advantages such as the ability to process helical gears with high precision.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the mechanism of the helical gear processing device of the present invention, Fig. 2 is a plan view of the work drive section, and Fig. 3
The figure is an example of the block diagram. 6... Traverse motor, 8... Work spindle motor, 14... Work, 15, 19, 2
5, 33...Pulse generator, 15A...Outer cylinder part,
22... Grinding wheel spindle motor, 24... Grinding wheel,
27, 34...Pulse selection output device.

Claims (1)

[Claims] 1 Equipped with a first pulse generator that outputs pulses with a frequency corresponding to the rotation of the tool, and a second pulse generator that outputs pulses with a frequency that corresponds to the rotation of the workpiece, the output pulse of the first pulse generator and second
In a gear processing device that compares the output pulses of a pulse generator and controls the speed of the work spindle according to the result to synchronize the rotation of the work with the rotation of the tool, the rotary shaft is connected to the work spindle and the outer cylinder part is a second pulse generator that is rotatable and outputs pulses at a frequency corresponding to the rotation of the rotating shaft; a third pulse generator that generates pulses in response to the relative movement amount of the workpiece and the grindstone; The outer cylindrical part of the second pulse generator is rotated in accordance with the output pulses of the pulse generator, and the frequency of the output pulses of the second pulse generator is adjusted according to the movement of the workpiece or the grindstone in the axial direction. 1. A helical gear processing device, comprising means for increasing or decreasing a frequency corresponding to rotation.