JPS62162416A - Nc hobbing machine - Google Patents

Abstract

PURPOSE:To prevent an accident of damage of a hobbing cutter upon power failure, by providing an electromagnetic clutch in a workpiece power transmission system and a flywheel in a hobbing cutter power transmission system so that the workpiece power transmission system is isolated upon cut-off of system power source. CONSTITUTION:A worktable 5 may separate a wheel therefrom by means of an electromagnetic clutch 21 disposed between the worktable 5 and the wheel 8. Further, a flywheel 22 aligned coaxially with a hobbing cutter 1 increases the rotational inertia force of the hobbing cutter 1. Meanwhile a power source cut-off detecting circuit 23 monitors a power source E for an NC device 9 to detect a power cut-off condition due to power failure, power cut-off manipulation or the like, and delivers a detection signal S for releasing a clutch 21. Accordingly, if the cut-off of power source occurs, a workpiece follows freely to the rotation of the hobbing cutter 1 so that they are both moderately decelerated in rotation at a rate which is substantially equal to that before the cut-off of power source, and are finally stopped at the same time.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an NC hobbing machine for machining various gears, and particularly relates to an improvement in means for preventing damage to the hob cutter when the power is cut off due to a power outage or a power off operation. .

[Conventional technology]

FIG. 2 is a block diagram showing a conventional NC hobbing machine of this type. In the figure, 1 is a hob cutter, 2 is a hob cutter driving motor, and the driving force of this hob cutter driving motor 2 is transmitted to the hob cutter 1 via a gear 3. On the other hand, 4
5 is a workpiece (hereinafter abbreviated as work), 5 is a work table that supports 9-94, and 6 is a work drive motor, and the drive force of the work drive motor 6 is unidirectional power transmission. It is transmitted to the work table 5 via the worm 7 and wheel 8 of the formula.

Further, the hob cutter driving motor 2 and the workpiece driving motor 6 are connected to a rotational speed signal S generated by a speed control signal given from the NC device 9 to each power amplifier 10.11.
Various gears are machined by setting the rotation ratio of the motor to a desired value according to the specifications of the workpiece, machining conditions, etc.

[Problem that the invention seeks to solve]

In conventional NC hobbing machines, if a power outage occurs during processing of a workpiece and the power is cut off by accidentally turning off the power, there is a high possibility that the hob cutter 1 will be damaged.

In other words, the hob cutter power transmission system and the workpiece power transmission system each have their own inertia force, frictional force, etc. during machining, and if the power goes out and the power goes out of control, both transmission systems will have different rotational descent curves over time. Slow down. Therefore, indexing ratio fluctuation occurs between both transmission systems, and rotation at a constant ratio is not possible until it comes to a stop.

In the initial stage where the index ratio fluctuation occurs, the workpiece 4, which is partially machined, plays the role of a gear, and one power transmission system applies a force to the other transmission system to maintain the rotation ratio. However, when the hob cutter power transmission system attempts to apply rotational force to the workpiece power transmission system, the workpiece 4 is a unidirectional power transmission mechanism due to the action of the worm 7 and wheel 8, but then the hob cutter 1 side It could not be rotated with the force of

For this reason, the hob cutter 1 bites into the teeth of the workpiece 4 during processing, causing damage. On the other hand, if the workpiece power transmission system applies rotational force to the hob cutter power transmission system, the structure of the hob cutter 1 will cause the worst case where the workpiece 4 collides with the hob cutter 1, so damage to the hob cutter 1 will still occur. I was invited.

The hob cutter is very expensive, and damage accidents such as those described above must be avoided as much as possible, and a method that can also prevent damage to the workpiece 4 has been desired.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an NC hobbing machine that can highly reliably prevent damage to the hob cutter even if the power source is cut off due to a power outage or a power-off operation.

[Means for solving problems]

The present invention is characterized by taking the following measures in order to solve the above-mentioned problems and achieve the object. Namely, a clutch mechanism is arranged in the power transmission system of the workpiece, and a 7-line system is installed in the power transmission system of the hob cutter. The system is characterized by a wheel that actively opens the work table's power transmission system when the system's power is turned off.

[For production]

By taking such measures, in the event of a power outage due to a power outage or a power off operation, the workpiece will freely follow the rotation of the hob cutter, and both will gradually decelerate at approximately the same rate as before the power outage. It rotates and then stops at the same time.

〔Example〕

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. Note that the same parts as in FIG. 2 are given the same reference numerals and detailed explanations will be omitted. In FIG. 1, reference numeral 21 denotes an electromagnetic clutch interposed between the work table 5 and the wheel 8, which allows the work table 5 to be disconnected from the wheel 8. Further, 22 is a flywheel disposed coaxially with the hob cutter 1, thereby increasing the rotational inertia of the hob cutter 1. On the other hand, 2
3 is a power-off detection circuit that monitors the power supply E to the NC device 9 and detects a power-off state due to a power outage or a power-off operation, etc. When a power-off state is detected, the electromagnetic clutch is activated by a detection signal S. 21, etc., will be actively released.

Next, the operation of this embodiment will be explained. When processing the workpiece 4 into a desired gear, the specifications and processing conditions of the workpiece 4 are input to the NC device 9.

Then, from the NC device 9 to the valley power amplifier 10.1
1 is given a suitable speed control signal, thereby generating a rotational speed signal SL.

S2 rotates the hob cutter drive motor 2 and the workpiece drive motor 6 at a predetermined number of rotations. Then, the rotational force of the hob cutter drive motor 2 is transmitted to the hob cutter 1 via the gear 3, and the rotational force of the workpiece drive motor 6 is transmitted to the work table 5 via the worm 7, the wheel 8, and the electromagnetic clutch 21. . As a result, the hob cutter 1 and the workpiece 4 rotate at an appropriate rotation ratio, and the hob cutter 1 processes the workpiece 4 to create a desired gear.

In this state, if a power outage occurs or the power is turned off by mistake and the power is cut off, the power cut-off state is first detected by the power cut-off detection circuit 23, and the detection signal S is sent to the electromagnetic clutch 21. , and the work table 5 becomes free. On the other hand, the hob cutter driving motor 2 at the initial stage of the power cut is rotated at the same rotation speed as before the power cut due to the electric power stored in the NC device 9, the power amplifier 10, and the like.

Therefore, the hob cutter 1t/'i applies a force to the contact surface of the free workpiece 4 to continue the 240 rotations of the tool before the power was cut off. This force is not sudden, and since the work table 5 is released by the electromagnetic clutch 21, it is smoothly transmitted to the work table 4, and as a result, the work 4 and the hob cutter 1 rotate at approximately the previous ratio.
A change in the indexing ratio between the two is almost impossible.

When the electric power stored in the ANC device 9, the power amplifier 10 of the hob cutter drive motor 2, etc. disappears, the rotational force of the hob cutter drive motor 2 disappears, and the rotation of the hob cutter 1 also decreases.However, in this case, The rotational speed of the hob cutter 1 is gradually reduced by the energy stored in the flywheel 22, and the rotational speed of the hob cutter 1 does not become slower than the rotational speed of the workpiece 4 until the hob cutter 1 stops operating. 1 gradually stops the work 4 with a light load, and the work 4 never collides with the hob cutter 1.

Thus, according to this embodiment, when the power supply is cut off due to a power outage or a power-off operation, the rotation of the hob cutter 1 decreases slower than the rotation of the workpiece 4, and the rotation of the hob cutter 1 decreases by 240 rotations. Following this, the hob cutter 1 and the workpiece 4 rotate at approximately the same ratio as before the power was cut off, so there is no risk of indexing ratio fluctuations that could damage the hob cutter 1. Therefore, even if the power supply is cut off, there is no risk of damage to the hob cutter 1, and damage to the workpiece 4 can be minimized, resulting in an extremely large effect not only in terms of safety but also in terms of economy.

〔Effect of the invention〕

As described in detail above, the present invention provides an electromagnetic clutch in the workpiece power transmission system, and a flywheel in the hob cutter power transmission system, so that when the system power is cut off, the workpiece power transmission system is actively operated. It was designed to be cut out. Therefore, according to the present invention, when the power is cut off due to a power outage, power off operation, etc., the rotational force of the hob cutter is transmitted to the workpiece, and both of them gradually decelerate and stop at approximately the same ratio as before the power cut. , NC that can highly reliably prevent damage to the hob cutter even if the power is cut off.
We can provide hobbing machines.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a conventional NC hobbing machine. In the drawing, 1... Hob cutter, 2... Hob cutter's driving motor, 3... Gear, 4... Workpiece (workpiece), 5...
・Work table, 6...Work drive motor, 10
．． 11... Power amplifier, 21... Electromagnetic clutch, 2
2... flywheel, 23... power failure detection circuit,
9...NC device.

Claims (1)

[Claims] In an NC hobbing machine that processes gears by rotating a workpiece and a hob cutter that processes the workpiece at a desired rotation ratio through respective power transmission systems, a clutch mechanism is disposed in the power transmission system of the workpiece. In addition, a flywheel is provided in the hob cutter power transmission system, and means is provided for actively opening the power transmission system of the work table to which the workpiece is attached by disengaging the clutch mechanism when the system is powered off. This is an NC hobbing machine that is characterized by the following.