JPH07110447B2 - Gear finishing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear finishing device, and more particularly to a gear finishing device having a gear pitch error correction function.

2. Description of the Related Art For the purpose of improving the surface roughness of tooth surfaces of spur gears and helical gears and improving the accuracy of tooth profile, finishing of gears is performed by grinding. In such a finishing machine by grinding, for example, a gear to be machined is supported on both sides by a headstock and a tailstock, and the gear to be machined is meshed with an internal gear-shaped grindstone, while the gear to be machined is rotated by a spindle motor. Accordingly, by basically rotating the grindstones synchronously by the grindstone driving motors, grinding is performed by utilizing the sliding contact between the tooth surfaces of the gear to be processed and the grindstone.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the conventional finishing device as described above, the gear to be processed and the grindstone are processed as if they are in the relationship of a gear pair for the purpose of improving the surface roughness and the tooth profile accuracy of the gear to be processed. It does not have a gear pitch measurement function or a pitch error correction function.

Therefore, the pitch accuracy of the gear to be machined depends on the machining before the finishing work, and the improvement of the pitch accuracy of the gear cannot be expected even though the finishing work is aimed at improving the surface roughness and the tooth profile accuracy.

Further, particularly in the case of a gear to be processed in which pitch accuracy is a problem, finishing processing for the purpose of pitch error correction must be performed separately, which increases the number of processing steps.

The present invention has been made in view of the above problems,
An object of the present invention is to provide a finishing device capable of improving the gear pitch accuracy by correcting the gear pitch error at the same time in finishing for the purpose of improving the surface roughness and tooth profile accuracy of the gear to be processed. .

MEANS FOR SOLVING THE PROBLEMS The present invention bites a gear to be processed which is supported on both sides by a head stock and a tail stock and is rotationally driven by a spindle motor, and a gear-shaped grindstone which is rotationally driven by a grindstone drive motor. In addition, in a finishing device for gears that finishes the work gear by rotating both gears synchronously, a gear pitch correction device that corrects the gear pitch after measuring the total number of pitches of the work gear Is equipped with.

In addition, this gear pitch correction device meshes the master gear with the master gear that moves forward and backward with respect to the gear that is supported on both sides by the headstock and tailstock and meshes with the gear to be machined. The gear pitch detection means for measuring the total number of pitches of the gear to be processed for each tooth rotation from the rotational displacement of the master gear when the gears are rotated one by one in the state where the gear pitch is detected. Obtain the pitch error correction amount necessary to average the pitch of all teeth of the processed gear based on the measured value of the total number of pitches, and determine the pitch error correction amount between the processed gear and the grindstone. It is composed of arithmetic and control means for giving to the control system of the spindle motor and the grindstone drive motor as a rotational phase difference generating signal for giving a phase difference.

Action In this structure, the processed gear has been subjected to the finishing process once with the headstock and the tailstock being supported by both ends, or the finishing process is still performed while the headstock and the tailstock are supported by both ends. After the unprocessed gear and the master gear mesh with each other, the gear is indexed and rotated by the main shaft motor one by one.
Then, the gear pitch when the gear to be processed is indexed and rotated is detected by the gear pitch detecting means each time, and the measured values of all the pitches are sequentially stored.

After that, the calculation control means performs a predetermined calculation to correct the pitch error correction amount necessary for averaging the measured values of all the pitches (for example, the difference between the maximum value and the minimum value of the measured pitch values is within the allowable range). Find the amount of pitch error correction needed to pay. At this time, at the same time, the direction required for the correction, that is, the positive direction or the negative direction in the rotation direction of the processed gear is specified.

Then, instead of the master gear, a grindstone is meshed with the gear to be processed, and the above-mentioned pitch error correction amount is given to the control system of the spindle motor and the grindstone drive motor as a rotational phase difference generation signal.

This rotation phase difference generation signal causes a predetermined amount of meshing phase deviation in the positive or negative direction in the meshing state of the gear to be processed and the grindstone, and either in the positive or negative direction of the gear to be processed. The grindstone is strongly pressed against one of the tooth surfaces. As a result, in the portion where the measured pitch value is relatively small, one of the positive and negative directions of the tooth surface is scraped off so as to widen the pitch, and as a result, the gear pitch is corrected and the total number of pitches is corrected. Are averaged.

Embodiment FIG. 1 to FIG. 4 are configuration explanatory views showing an embodiment of the present invention.

As shown in FIGS. 1 and 2, a gear to be processed having a shaft portion S (in this embodiment, an example of a helical gear is shown,
Hereinafter, the work W is supported by the chuck 2 and the head center 3 on the headstock 1 side and the other end by the tail center 5 on the tailstock 4 side, and then rotated by the spindle motor 6. Driven. Reference numeral 7 denotes a table on which the head stock 1 and the tail stock 4 are mounted, and the table 7 is movable in the axial direction of the shaft portion S.

On the outer periphery of the work W, an internal gear-shaped grindstone 8 that meshes with the work W is provided so as to be supported by a grindstone holder 11, and the grindstone holder 11 is rotatably supported by a grindstone base 9 via a bearing 10. Has been done. A chain sprocket 12 is fixed to the outer periphery of the grindstone holder 11, while a chain 15 is wound between the chain sprocket 12 on the grindstone holder 11 side and the chain sprocket 14 on the grindstone drive motor 13 side. 8 is rotationally driven by a grindstone drive motor 13.

Therefore, after engaging the work W and the grindstone 8,
By rotating the work W by the spindle motor 6 and the grindstone 8 by the grindstone driving motor 13, respectively, the work W and the grindstone 8 rotate like a pair of gears,
Due to the sliding contact between the two tooth surfaces, the tooth surface on the work W side is subjected to grinding finishing.

The spindle motor 6 and the grindstone drive motor 13 each have a pulse generator 16 or 17 as a position detector, and form a position feedback loop with the positioning control device 18.

A gear pitch measuring unit 19 is arranged so as to be adjacent to the table 7. This gear pitch measuring unit 19 has a slider 21 mounted on a base 20 as shown in FIG. 3. The slider 21 includes a feed motor 22 and a ball screw.
By the action of 23, the work W is moved forward and backward in a direction orthogonal to the axis of the work W. The forward / backward movement of the slider 21 is controlled by the positioning control device 18.
24 is a pulse generator.

A master gear 25 having a reference tooth profile is provided at the tip of the slider 21.
Is rotatably mounted, and the master gear 25 is directly connected to an input shaft of a rotary encoder 26 as gear pitch detecting means.

Therefore, as described later, when measuring the gear pitch of the work W, the slider 21 is moved forward to engage the master gear 25 with the work W, and then the work W is indexed and rotated by the spindle motor 6 one by one. The master gear 25 also rotates synchronously, whereby the total number of pitches of the work W is sequentially detected by the rotary encoder 26.

The output of the rotary encoder 26 is input to the arithmetic control unit 28 that constitutes the gear pitch measuring device 27 together with the gear pitch measuring unit 19. The arithmetic control unit 28 temporarily stores the actual pitch measurement values of all the pitches of the workpiece W obtained by the rotary encoder 26, and then calculates and obtains the pitch error correction amount necessary for averaging the pitches. The pitch error correction amount is output to the control system of the spindle motor 6 and the grindstone drive motor 13 as grinding allowance data necessary for pitch error correction.

In the finishing apparatus configured as described above, as shown in FIG. 1, the work W supported by both the head stock 1 and the tail stock 4 and the grindstone 8 are engaged with each other, and then the spindle motor 6 and the grindstone are engaged. The drive motor 13 is driven to synchronously rotate the work W and the grindstone 8. As a result, the work W and the grindstone 8 rotate in a gear pair relationship, and the tooth surface on the work W side is ground due to the sliding contact between the tooth surfaces of the two. At this time, the slider 21 of the gear pitch measuring unit 19 is retracted to a position where it does not interfere with the grindstone base 9.

When the processing of the work W is completed, the grindstone base 9 is temporarily retracted, and instead, as shown in FIG.
The slider 21 of 19 is advanced to move the work W and the master gear 25.
Mesh with.

Then, the spindle motor 6 is driven according to an instruction from the positioning control device 18, and the work W is indexed and rotated by one tooth (each reference pitch). When the work W is indexed and rotated, the master gear 25 meshing with the work W is synchronously rotated, and the actual pitches of all the pitches of the work W are sequentially detected by the rotary encoder 26, and the measured values are stored in the arithmetic control unit 28. To be done.

When the measurement of the total number of pitches of the work W is completed, the slider 21 of the gear pitch measuring unit 19 moves backward while the arithmetic control unit
At 28, a predetermined calculation is performed based on the measured values of all the pitches.

That is, in the arithmetic control unit 28, for example, it is determined whether or not the value of the difference between the maximum value and the minimum value of the measured values of all pitches is within the allowable range, and the difference value is within the allowable range. For example, a machining end command is given to the positioning control device 18.

On the other hand, if the difference value is not within the allowable range, the pitch error correction amount necessary for keeping the difference value within the allowable range is calculated. At the same time, in correcting the pitch error, is it necessary to scrape the tooth surface in the positive direction of each tooth surface?
Alternatively, it is specified whether the tooth surface in the negative direction should be cut.
Then, the arithmetic and control unit 28 applies the pitch error correction amount to the control system of the spindle motor 6 and the grindstone drive motor 13,
It is given as a rotational phase difference generation signal for creating a rotational phase difference between the work W and the grindstone 8.

The rotation phase difference referred to here is, as shown in FIG. 4, a meshing position at the time of first machining and a meshing position at the time of machining in the meshing state of the teeth on the work W side and the teeth on the grindstone 8 side. The offset amount a between them corresponds to the grinding allowance when the pitch error is corrected.

After this, when the work W and the grindstone 8 are re-engaged and the machining is started, the work W and the grindstone 8 are rotated by the offset amount a in the positive direction or the negative direction as compared with the initial machining as described above. In order to rotate synchronously while being strongly pressed with a phase difference, in the part where the pitch was relatively small in the previous pitch measurement step, either the positive or negative face of the tooth surface is offset. It is scraped off in the width of the amount a.

As a result, the gear pitch error of the work W is corrected and the pitches of all the pitches are averaged.

EFFECTS OF THE INVENTION As described above, according to the present invention, since it has a function of correcting the pitch error after measuring the pitch of the gear to be processed, it is possible to improve the surface roughness and the tooth profile accuracy of the gear. It is possible to correct the pitch error at the same time as the desired finishing process, thereby improving the accuracy of the gear and reducing the processing man-hour.

Also, the pitch of the gear to be machined set on the machining device is measured on the machining device, and the pitch error correction amount is directly fed back to the drive system of the machining device to correct the pitch error. The pitch accuracy itself is also greatly improved.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing an embodiment of the present invention, FIG. 2 is an explanatory view showing a meshing state of a gear to be processed and a master gear, and FIG. 3 is a sectional explanatory view of a gear pitch measuring unit. FIG. 4 is an enlarged view of an essential part showing a meshing state between the work and the grindstone. 1 ... Headstock, 3 ... Head center, 4 ... Tailstock, 5 ... Tail center, 6 ... Spindle motor, 8 ... Grindstone, 9 ... Grindstone base, 13 ... Grindstone drive motor, 19 ... … Gear pitch measuring unit, 21 …… Slider,
25 …… master gear, 26 …… rotary encoder (gear pitch detecting means), 27 …… gear pitch measuring device, 28…
... Computational control unit, W ... Gear to be processed.

Claims (1)

[Claims] 1. A gear to be machined, which is supported by a headstock and a tailstock and is rotatably driven by a spindle motor, and a gear-shaped grindstone which is rotatably driven by a grindstone drive motor. In a finishing device for a gear, which is adapted to finish the processed gear by rotating the gear synchronously, a gear pitch correction device for correcting the gear pitch after measuring the total number of pitches of the processed gear is provided. The gear pitch correction device operates in a state in which the master gear that moves forward and backward with respect to the gear to be supported, supported by the headstock and tailstock, meshes with the gear to be machined, and the gear to be machined and the master gear mesh with each other. A tooth that measures the total number of pitches of the gear to be processed for each tooth rotation from the rotational displacement of the master gear when the gear is rotated one by one. Based on the measured values of the total number of pitches obtained by the vehicle pitch detection means and the gear pitch detection means, find the pitch error correction amount necessary to average the pitches of all teeth of the gear to be processed, and correct this pitch error correction. And an arithmetic control means for giving the amount to the control system of the spindle motor and the grindstone drive motor as a rotational phase difference generation signal for providing a rotational phase difference between the gear to be processed and the grindstone. Finishing device for gears.