JPH07100257B2 - Gear processing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a finish machining machine such as gear shaving or grinding, in which the gear-shaped tool and the workpiece gear are engaged while controlling the rotational speed and phase angle. The present invention relates to a gear processing machine that processes by.

(Prior Art) In a gear machining method in which the tooth flanks of a workpiece gear are ground by contacting the tooth flanks of both the workpiece gear and the tool, either A method of applying a driving force to one of them has been generally used.
Since this method does not need to consider the phase synchronization of the engagement between the tool and the work gear, the gear processing machine can be constructed with a simple mechanism. However, in this method, for example, when the driving force is applied to the work gear, the tool is in a rotating state, and in this state, one tooth surface of both the tool being machined and the work gear is always Since they do not come into contact with each other at a constant phase and a constant pressure, there is a problem in that the accuracy of the gear surface and the pitch accuracy of the workpiece gear after processing are low. Therefore, in order to improve the accuracy of the gear surface and the pitch accuracy, for example,
As a first method, the contact pressure between the two is controlled to be constant as described in JP-B-58-54935, and as a second method, as described in JP-A-59-156613. In addition, the method of keeping the phase of the work gear and the tool mechanically constant by the guide gear pair has been adopted. However, in the first method, there is a drawback that the machining accuracy follows the pre-machining so that the ability to improve the pitch error is small, and in the second method, it is difficult to maintain the accuracy due to wear of the guide gear pair. There is a drawback in that the gear with a shaft cannot be machined, and eventually, with these methods in which a driving force is applied to either the workpiece gear or the tool, there is a limit in improving the machining accuracy.

Therefore, in order to further improve the machining accuracy, drive force is applied to both the tool and the workpiece gear, and a servo motor is used as the drive force. A third method is conceivable in which the phase synchronization of meshing during processing is taken. Compared with the first and second methods, this third method requires a large driving force for both the tool and the workpiece gear, and requires NC control of these driving forces, resulting in a large-scale device. However, since the tool that contacts during machining and the one tooth surface of the workpiece gear can be kept in contact with each other at a constant phase and with a constant pressure, the precision and pitch accuracy of the gear surface of the workpiece gear after machining can be dramatically improved. There is a great advantage of improving.

(Problems to be Solved by the Invention) However, there are the following problems in performing the phase control for machining by the third method.

FIG. 6 is a view showing the meshing state of a normal gear. When the distance between the gear axes is such that the respective pitch circles overlap at one point, the teeth make contact at two points. I)
However, in the meshing of both the gear-shaped tool (1) and the workpiece gear (2) shown in FIG. 5 which are used in the machining machine according to the present invention, the tool (1) and the workpiece gear (2) are meshed. ) Tool for the purpose of always contacting only one tooth surface (1)
Has a small tooth thickness, and the tooth thickness changes further due to wear of the tool. Therefore, there is a problem that the initial phase of meshing must be shifted and controlled as shown in FIG. B) On the other hand, in actual machining, the opposite tooth surface must also be machined, so the phase must be shifted in the opposite direction by the same amount during machining. C) In addition, in order to automatically load the work gear (2) and set the phase without the intervention of the staff, the inter-axis distance and the rotation angle of the work gear (2) and the tool (1) are controlled. In addition, a mechanism for contacting both tooth surfaces with a constant pressure is required.

It is an object of the present invention to provide both tool and workpiece gears for phase synchronization of the meshing engagement during tool and workpiece gear machining.
In a gear processing machine that is driven by NC control, the initial phase when the gears of the workpiece gear and the tool are engaged before the start of machining, without adding a reference pin or a mechanical dividing device. The object is to provide a gear processing machine that can be set in a desired manner and can process a predetermined gear.

(Means for Solving the Problems) Therefore, the present invention is a machine for grinding or shaving a straight tooth gear or a helical gear with a gear-shaped tool, and the tool is a workpiece having only one tooth surface. A gear machining machine for machining by contacting with a gear and rotating by engaging and rotating, a tool shaft (1 ') for gripping the tool (1) and a work gear shaft (20) for gripping the work gear (2). Are driven by the first and second servomotors, respectively, and the tool (1) and the workpiece gear (2) are rotated at a rotational speed inversely proportional to the number of teeth so that the momentary meshing phase of both is constant. Has a pulse distributor (9) for pulse distribution, and outputs a speed command signal to a speed control circuit unit for controlling one of the servo motors when initial phase alignment of the tool (1) and the machining gear (2) is performed. Degree command circuit (14), a torque control device for outputting a torque control value to the speed control circuit section during the initial phase adjustment (17)
During the initial phase alignment, the speed control circuit section rotates the servomotor controlled by the speed control circuit section based on the speed command, and at this time, the pulse distributor (9) restrains the other of the servomotors. The output is stopped so that the tool (1) and the workpiece gear (2) are brought into contact with each other on one tooth surface, and the tool (1) and the workpiece gear (2) make the torque. When a pressure is applied to each other by the torque specified by the control value and the balance is stopped, a command is issued to set the rotation angle of the tool shaft (1 ') and the workpiece gear shaft (20) at this position to the initial phase "zero". Distributor (9)
The above-mentioned problems are solved by providing a gear machining machine characterized by including an initialization device (13) for outputting to.

(Operation) At the time of initial phase alignment between the tool (1) and the workpiece gear (2), the speed control circuit portion of the servo motor that drives either the tool (1) or the workpiece gear (2) is driven. Since the speed command signal that specifies the rotational speed when the tool (1) or the work gear (2) is engaged and the torque control value that specifies the upper limit of the torque are input, for example, the work When the gear (2) is driven, one tooth surface of the workpiece gear (2) rotated at the rotation speed designated by the speed command signal is in a state of being restrained and stopped. When the torque value applied to the second servomotor that drives the workpiece gear (2) after coming into contact with the one tooth surface of the tool (1) reaches the specified torque control value, the tool (1) and the machining are processed. The counter gears (2) are stopped by the mutual crimping of one tooth surface. The initializing device (13) sends a command to the pulse distributor (9) to set the rotation angle of the tool shaft (1 ') and the workpiece gear shaft (20) at this position to the initial phase "zero". Is output.

(Example) The present invention is based on the concept of the above-mentioned phase control, and when starting the rotation control, is for automatically setting the initial phase angle so that the finishing dimension is achieved with high accuracy, A specific example will be described below.

FIG. 2 is a schematic elevational structure diagram for explaining the mechanism of the gear machining mechanism according to the present invention. Gear-shaped tool (1) and workpiece gear (2) directly connected to servomotors (3) and (4)
Are engaged by the swivel base (21) with a certain crossing angle, and the inter-axis distance is determined by the slide drive servomotor (22) via the ball screw and the cutter holding base (21) integrated with the swivel base (21). It can be changed by moving ′). FIGS. 3 (a), (b), (c) and (d) show how the tool (1) processed by the gear processing machine of the present invention and the workpiece gear (2) are meshed with each other. FIG. 1 is a block diagram showing the configuration of a control system that enables such processing.

The tool shaft (1 ') for gripping the gear-shaped tool (1) is the first
It is rotated by a servo motor (3), and the rotation is respectively fed to a first speed control circuit section (5) and a first servo motor position control circuit (7) which control the first servo motor (3) by a pulse encoder (11). The workpiece gear shaft (20) which is returned and grips the workpiece gear (2) capable of meshing with the tool (1) is rotated by the second servomotor (4), and the rotation thereof is a pulse encoder (12). Are fed back to the second speed control circuit section (6) for controlling the second servo motor (4) and the second servo motor position control circuit (8), respectively, and the phases of the tool (1) and the workpiece gear (2) are returned. The phase angle controller is formed in cooperation with a pulse distributor (9) which controls the angle to be kept constant at all times. The torque control value from the torque control device (17) can be input to the second speed control circuit section (6) via the switch (16). The speed command signal output from the speed command circuit (14) to the second speed control circuit section (6) via another switch (15) is used as the input signal of the second servo motor position control circuit (8). On the other hand, it is possible to selectively input by passing. Further, when the torque control value and the speed command signal are input to the second speed control circuit (6), the tool (1)
The first servomotor (3) for controlling the motor is designed not to rotate. Therefore, when setting the initial phase when the tool (1) and the workpiece gear (2) are engaged,
Activate the speed command circuit (1
4) output speed command signal and torque control device (1
By inputting the torque control value output by 7) into the second speed control circuit section (6), the second servomotor (4) for controlling the workpiece gear (2) is operated. As a result, the workpiece gear (2) is rotated at the rotation speed designated by the speed command signal, and the rotation of the workpiece gear (2) causes the tool (1) whose one tooth surface of the workpiece gear (2) is stopped. ), The tool (1) and the workpiece gear (2) are crimped at the torque specified by the torque control value and stopped at that position, and the initialization device (13) makes this balance. A command for setting the rotation angle of the tool shaft (1 ') and the workpiece gear shaft (20) at the stopped position to the initial phase "zero" is output to the pulse distributor (9). The pulse distributor (9) offsets the rotation angle of the tool shaft (1 ') and the workpiece gear shaft (20) to the initial phase "zero" in response to a command from the initializing device (13). Thereafter, the pulse distributor (9) adjusts the tool (1) and the work gear (2) so that the momentary meshing phase of the tool (1) and the work gear (2) during processing becomes constant. The number of revolutions inversely proportional to the number of teeth is set to the first and second servo motor position control circuits (7).
It operates so as to output to (8).

In operation, first, the tool (1) and the workpiece gear (2) are engaged with each other with a slight axial distance (see FIG. 3 (a)), and then one of the slide drive servomotors (22) is used. The tool shaft (1 ') and the workpiece gear shaft (20) are brought close to each other so that the pitch circles are overlapped by moving (FIG. 3 (b)). Here, the control loop in FIG. 1 forms a position control loop in which one is commanded from the first servo motor position control circuit (7) to the first speed control circuit section (5), while the other is a switch ( The second servo motor position control circuit (8) is disconnected by 15), and the speed command signal commanded by the speed command circuit (14) is directly input to the second speed control circuit section (6) to form a speed control loop. . At this time, at the same time, a preset torque control value is commanded from the torque control device (17) via the switch (16) to the current control input of the second speed control circuit section (6). Of course, at this time, there is no output from the pulse distributor (9) which is the position command distribution control unit, and therefore the first servo motor (3) is in the servo lock state, that is, the rotational force is applied to the tool shaft (1 ') from the outside. However, the servo motor (3) is locked (locked) and stopped. As a result, the second servomotor (4) rotates and one tooth surface of the tool (1) and the workpiece gear (2) is crimped to the torque specified by the torque control value and the balance is stopped. Here, the rotation angle of the second servo motor (4) is constantly counted because the pulse train generated by the encoder (12) is input to the second servo motor position control circuit (8) and counted. And the rotation angle of the work gear shaft (20) can be read.
Therefore, in this state, the tool shaft (1 ') and the work gear shaft (2
The initialization device (1
Offset the command by 3) and then switch (15)
(16) is switched, the second speed control circuit section (6) and the second servomotor position control circuit (8) are connected to form a position control loop, and the preprogrammed tool (1) and workpiece gear ( Position and speed commands corresponding to the number of teeth in 2) are given from the pulse distributor (9) and rotated (Fig. 3 (c)). In this state, the meshing phase of the tool (1) and the work gear (2) is always constant, and the slide drive servomotor (22) is moved to make the inter-axis distance close to each other, and the feed is performed to make the predetermined size. Can be obtained (Fig. 3 (d)). FIG. 4 shows a machining cycle diagram of the gear machining machine according to the embodiment of the present invention.

(Effect of the Invention) According to the present invention, both the tool and the compound gear are provided in order to achieve the phase synchronization of the meshing engagement between the tool and the workpiece gear during machining.
In the gear machining machine driven by NC control, the initial phase when the gears of the tool and the workpiece gear mesh with each other can be set automatically, so the tool tooth thickness is small due to tool wear. Even if it changes
It is possible to always set the phase synchronization between the tool being machined and the workpiece gear to an optimum state, and thereby it is possible to suppress variations in machining accuracy to a small level. In addition, even if one tooth surface of one of the workpiece gears is machined and then the other tooth surface of the opposite side is machined, the initial phase for meshing should be set again before machining the other tooth surface of the opposite side. By doing so, it is not necessary to shift the phase in the opposite direction by the same amount during the machining as in the conventional case.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control system of an embodiment gear machining machine according to the present invention, and FIG. 2 is a schematic elevational structure view of an embodiment gear machining machine according to the present invention, FIG. 3 (a).
5 (b), (c), (d) and FIG. 5 are explanatory views showing a meshing state of a tool and a workpiece gear machined by the gear machining machine, and FIG. 4 is a machining cycle diagram of the gear machining machine. , FIG. 6 is an explanatory view similar to FIG. 5 in normal gear machining. (1) …… Tool (1 ′) …… Tool axis (2) …… Workpiece gear (3) (4) …… Servo motor (5) (6) …… Speed control circuit section (7) (8) Servo motor position control circuit (9) Pulse distributor (phase angle control device) (13) Initializing device (14) Speed command circuit (15) (16) Switch (switching device) ( 17) …… Torque control device (20) …… Workpiece gear shaft

Claims (1)

[Claims] 1. A machine for grinding or shaving a straight-toothed gear or a helical gear with a gear-shaped tool, wherein the tool is brought into contact with a workpiece gear only on one tooth surface to engage and rotate. In a gear machining machine for machining, a tool shaft (1 ') for gripping the tool (1) and a workpiece gear shaft (20) for gripping the workpiece gear (2) are driven by first and second servomotors, respectively. And a pulse distributor (9) for rotating the tool (1) and the workpiece gear (2) at a rotational speed that is inversely proportional to the number of teeth so that the momentary meshing phase of both is constant. A speed command circuit (14) for outputting a speed command signal to a speed control circuit unit for controlling one of the servo motors at the time of initial phase alignment of the tool (1) and the machining gear (2).
And a torque control device (17) that outputs a torque control value to the speed control circuit unit during the initial phase matching, and the speed control circuit unit controls the speed control circuit unit based on the speed command during the initial phase matching. The servomotor to rotate and at this time the pulse distributor (9) stops the output to stop the other of the servomotors in a restrained state, whereby the tool (1) and the work gear (2) are stopped.
When the tool (1) and the workpiece gear (2) are pressed against each other at a torque specified by the torque control value and stopped in equilibrium, the tool shaft ( 1 ') and an initialization device (13) for outputting a command for setting the rotation angle of the workpiece gear shaft (20) to the initial phase "zero" to the pulse distributor (9). Processing machine.