JP2995258B2 - Gear measuring method and gear grinding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear grinding machine equipped with an NC, and more particularly, to a gear grinding and shaping process of a gear by a grinding wheel, and a gear measuring / gearing gear with an NC capable of measuring a gear without removing the gear from a position at the time of grinding. Related to grinding machines.

[0002]

2. Description of the Related Art Normally, at least one of a high-precision gear that is ground by a gear grinder is inspected for at least one tooth in a machining lot, a tooth trace, and the like, and it is determined whether machining setting conditions are correct. Make sure that you are correct before processing the rest of the lot. Conventionally, the measurement of gear accuracy in this type of gear grinder has been performed on a dedicated gear measuring machine.However, in order to improve workability, it is possible to measure the gear directly on the gear grinder after grinding. Is being developed. For example, real
As shown in Japanese Unexamined Patent Publication No. Hei 1-92322, a measuring element of a detector fixed to a grindstone head is brought into contact with a tooth surface of the gear while a grounded work gear is attached to a work spindle of a gear generating machine. And the base gear performs a basic rolling motion of the gear to be machined by spindle rotation and lateral feed of the headstock, and outputs an output signal of the detector to a measurement control device provided separately to perform data processing to detect tooth profile accuracy. Has already been proposed.

[0003]

The method of checking the accuracy of a gear using a dedicated gear measuring machine after processing the gear requires time for changing the work and setting up the setting.
On the other hand, the gear processing machine having the gear measuring function described above is limited in the types of gears that can be applied, and includes a mechanism for rolling the gear to be measured, a measurement control device for processing data of an output signal of the detector, and an arithmetic device. Must be added separately,
There is a problem that the cost is high.

The present invention utilizes a function inherent in a gear grinding machine with an NC, and allows a precision measurement of a gear after machining on a gear grinding machine with an NC without adding a new control function for measurement. It is an object of the present invention to provide a measuring method and a gear measuring and gear grinding machine.

[0005]

According to the gear measuring method of the present invention, a measuring element is mounted on a grindstone holder of a gear grinding machine with NC, and the control function of each part provided in the gear grinding machine with NC is controlled as required. The gear tooth profile, tooth traces, gear pitch and the like are measured on the NC gear grinding machine.

In the gear measuring and grinding machine according to the present invention, a measuring element is provided on a grindstone holder of an NC gear grinding machine so as to contact a tooth surface of a gear mounted on a gear holding portion of the gear grinding machine. Attach, and the tracing stylus can be retracted to a position that does not interfere with the gear and the grinding wheel during gear grinding ,
The tracing stylus is pivotally attached to the whetstone holder and the gear
Stylus holding arm that can be tilted rearward from the position facing
At the position where the tracing stylus faces the gear.
Stopper means for positioning the probe holding arm
It is provided on a stone holder .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view of an NC gear grinding machine according to an embodiment of the present invention, and FIG. 2 is a side sectional view taken along line AA of FIG. An X-axis table 20 is placed on a T-shaped main body bed 21, and an indexing table 13 and a tailstock 14 are further axially centered on the X-axis table 20 (A axis).
And the gear to be machined (see FIGS. 1 and 2)
(Not shown) is loaded. The X-axis table 20 is moved in the left-right direction (X) by the X-axis servomotor 16 on one side of the bed via the ball screw shaft 18 and the ball screw nut 17.
(The axis direction), and the gear holding portion of the indexing table 13 is indexed and rotated around the axis by an A-axis servomotor 15. At the rear center of the T-shaped bed 21, a column 1 that can move back and forth in the front-rear direction (Y-axis direction) by a Y-axis servo motor 12 via a ball screw shaft 10 and a ball screw nut 11 is mounted. Similarly, a Z-axis table 5 which is movable in the vertical direction (Z-axis direction) by a Z-axis servo motor 4 at the upper part of the column via a ball screw shaft 3 and a ball screw nut 2 is mounted. Further, a whetstone holder 7 is provided on the front surface of the Z-axis table 5.
Is mounted, and a grinding wheel 9 formed into the shape of the tooth groove of the gear to be machined is supported on the grinding wheel holding table 7. 8 is a grinding wheel 9
Is a grindstone spindle motor that rotationally drives the wheel. The grinding wheel holding table 7 is turned on the Z axis table 5 around a horizontal axis (B axis) passing through the center of the grinding wheel axis perpendicular to the axis of the A axis by the B axis servo motor 6 held on the Z axis table 5. It is possible. Therefore, when the grinding gear is a helical gear, the grinding wheel holding table 7 (grinding wheel 9) can be tilted by an amount corresponding to the torsion angle of the gear. When the B-axis servo motor 6 is not used, the grindstone holder 7 may be manually tilted around the B-axis.

When grinding the gears, the gear to be machined is indexed by the indexing table 13.
And the tail stock 14, mesh with the grinding wheel 9 and grind the X-axis servo motor 16 while moving the gear to be cut in the face width direction. When the grinding of one tooth groove is completed, the grinding gear is rotated by one pitch by the servo motor 15 connected to the indexing table 13 to grind the next tooth groove.
When a cut is made during grinding or a crown is added to a gear to be machined, the movement of the grinding wheel 9 is also controlled by the Y-axis servo motor 12 and the Z-axis servo motor 4 in the Y-axis direction and the Z-axis direction. When the grinding wheel is formed or corrected, a dresser is mounted between the index table 13 and the tail stock 14 instead of the work gear, and the axes can be simultaneously controlled on the main grinding machine. This is disclosed in Japanese Patent Application No. 2-214154.

A gear measuring and grinding machine according to an embodiment of the present invention is configured by attaching a measuring element such as an electric micrometer to the above-described gear grinding machine with NC capable of simultaneously controlling at least three axes. FIG. 3 is a side view of the grindstone holder 7 to which the measuring element according to one embodiment of the present invention is attached. Whetstone holder 7
1 and 2 except that a base end of a substantially L-shaped measuring element holding arm 22 is pivotally mounted at a position on the side of the grinding wheel holding table adjacent to the grinding wheel 9. A probe 23 such as an electric micrometer is attached to the tip of the arm 22. The tracing stylus holding arm 22 is rotatable from a state at the time of measurement in which the tracing stylus 23 indicated by a solid line position in the drawing extends toward the cut gear, to a storage position (shown by a broken line) which is flipped upward. In order to position the arm 22 at the time of measurement, a stopper 24 is provided on the side of the grindstone holding table 7 to be in contact with the back of the arm 22. Similarly, a stopper 25 is also provided on the upper surface of the grindstone holder 7 to determine the storage position of the tracing stylus holder arm 22. For example, when the measurement of one tooth surface is completed and the gear is indexed and rotated by the stopper 24 at the time of measurement, the tracing stylus holding arm 22 is raised to the storage position so that the repetition accuracy falls within about 0.5 μm. Becomes easier.

As shown in FIG. 4, a tip 30 of the tracing stylus 23 with respect to the gear shaft center (A-axis) is provided by mounting a cylindrical body 30 (work arbor, center spindle, etc.) having a known radius between the tail stock 14 and the indexing table 13. Position. This may be directly applied to the reference grinding portion of the gear. When the repeatability due to the rotation of the tracing stylus holding arm 22 is not good, the tracing stylus 23 is positioned each time as shown in FIG.

FIG. 5 is a view showing the principle of measurement of the tooth profile of an involute gear according to an example of the present invention. The movement of the Y-axis table and the Z-axis table and the A
The tip 23a of the tracing stylus 23 is moved from the point A to the point B in FIG. The deflection of the tip 23a of the tracing stylus 23 at that time is output as data. The stylus 23 during measurement always has a constant measurement.
Contact movement on the tooth surface with constant pressure. But production of tooth profile
The error is remarkable, and the tip 23a of the tracing stylus 23
In extreme cases where gaps occur, errors beyond the measurement range
Judge as the difference. A control program for each axis required for measurement can be used for grinding a work gear. When the movement of each part is correct and the gears are made according to the theory, contact point 2
The swing of 3 becomes zero. Here, αA is the pressure angle at point A, α
B is the pressure angle at point B, and E and F are the base points of the tooth surface.
(The intersection of the base circle and the tooth surface). Angle AOP = αA, Angle B
OP = αB. Length from the nature of the involute curve
PA = arc PE, length PB = arc PF, and triangle A
TanαA = PA / rg in OP, triangle BOP
Where tanαB = PB / rg. Rg is basic
Is the radius of the circle. Therefore, tan αA is an arc on the base circle C
Similarly, the central angle of PE, tanαB, is the arc PF on the base circle C.
Is the central angle of Drawing Y-Z coordinates of the point A on the coordinate (YA, ZA) and the point B when the coordinates (YB, ZB) is _{YB = YA + Lsinθ 1, ZB} = ZA + L cosθ 1
If the central angle of the arc EF on the base circle C is θ, then θ
= TanαB-tanαA. Also apparent from FIG.
Θ ₁ = θ ₂ + αA. Here, L is the moving distance of the tip 23a of the tracing stylus from point A to point B. The tip 23a of the tracing stylus moves in the Y-axis direction and the Z-axis direction from the point A to the point B while being in contact with the one-side tooth surface 31a of one tooth due to the rotation of the gear 31 in the A-axis direction. The tooth profile of the surface 31a is measured. When the tooth profile measurement is completed for one tooth, the gear 31 is indexed and rotated by one pitch, and the tip 23a of the tracing stylus is returned to the original position again to start the next measurement.

In the measurement principle shown in FIG. 5, θ ₁ = θ ₂
If the initial setting is made so that + αA = 0, it is not necessary to move the tracing stylus in the Y-axis direction, and measurement can be performed by two-axis control of the A-axis and the Z-axis. If θ ₁ = θ ₂ + αA = 90 °, then
Measurement can be performed by two-axis control of the A axis and the Y axis without moving in the Z direction.

In addition to the tooth shape measurement example based on the principle of FIG. 5, the present invention may employ a method of following the coordinates of the tip of the tracing stylus by NC control while making the stylus contact the tooth surface. In this case, the tooth profile can be measured without necessarily using the involute gear. In the case of an involute gear, the arc correction program of the NC unit is used to approximate the involute tooth profile curve with an arc, divide one tooth surface into several arcs, and move the stylus to follow the arc. Let it. In this method, since the contact position of the tip of the tracing stylus changes, tool diameter correction is similarly performed using the attached NC device.

FIG. 6 is a view showing the principle of measurement according to still another example of tooth profile measurement according to the present invention. This embodiment is a method in which a tracing stylus is applied to the tooth surface 31a of the gear 31 by NC control to read the coordinate value of that point. Specifically, a point on the tooth profile curve S of any one tooth is subdivided into fine points. (For example, 50 divisions), the theoretical tooth profile at each point is represented by YZ coordinates, and the tip 23a of the tracing stylus 23 is actually brought into contact with that point to obtain the actual Y shape.
-Measure the Z coordinate value and measure the tooth profile by comparing the theoretical YZ coordinate value and the actual coordinate value at each point. The difference between the theoretical value and the actual coordinate value is the tooth profile error. Also in this case, tip 2
Since the contact position 3a changes, it is necessary to perform tool diameter correction using a program of the NC device. This embodiment can be applied to any of a cycloid gear, a trochoid gear, and an involute gear.

Next, measurement of gears other than the tooth profile will be described. FIG. 7 is a schematic view showing the principle of measuring the gear pitch.
Measuring elements 26 and 27 such as a pair of electric micrometers are attached to the front or side of the grindstone holder 7, and the grindstone is held at a portion that is immovable in the Y-axis direction, specifically, at a side of the X-axis table 20. A detector 28 such as an electric micrometer for detecting the forward position of the table 7 is pivotally mounted. In this embodiment, the pair of tracing styluses 26 and 27 is a pitch circle 29 of the gear 31.
The interval between them is determined so as to come into contact with the tooth surfaces 31a and 31b. The pitch of the gears is measured by both measuring elements 26 and 27.
Obtained from readings. The measurement procedure is as follows. First, the grindstone holding table 7 is advanced to set both the tracing styluses 26 and 27 on the tooth surfaces 31a and 31b on or near the pitch circle of the gear 31 on the indexing table (Y− Let the Z coordinate be Y ₀ , Z ₀ ), and move the grindstone holder 7 in the Y-axis direction (direction away from the gear)
Retreat to Then the A-axis by one pitch rotation, the grinding wheel holder 7 is again advanced in the Y-axis direction to position the position of the Y _0. In this case the position of the wheel holder 7 with detector 28 in the X-axis table 20 to check whether the returned to position correctly Y _0. By displaying the difference between the readings of both the tracing styluses 26 and 27 at this time, a single pitch error is obtained. This operation is repeated N times or 360 °. According to this method, since the difference between the pair of tracing styluses is obtained, the A-axis indexing error does not enter into the measuring error. The accumulated pitch error and the adjacent pitch error can be obtained by taking in the data of each tracing stylus and performing data processing.

In the case of tooth trace inspection, one of the tooth surfaces of an arbitrary tooth
A probe may be applied to the point to move in the tooth width direction (X-axis direction), and at the same time, the A-axis may be rotated by the lead angle (in the case of a helical gear). In this case as well, if the accuracy of the grinding machine is good and the gears are ground according to the theory, the runout of the tracing stylus becomes zero. As described above, the helical gear is controlled by the simultaneous control of the two axes of the X axis and the A axis. However, in the case of the spur gear, the movement may be performed only in the X axis direction.

In the various measurements described above, data can all be obtained by electric signals using an electric micrometer or the like. Therefore, these data can be taken into a computer, and the result can be used to automatically determine the accuracy of the gear accuracy. Further, the data of the measurement results of the tooth profile and the tooth line are processed, and Y
The deviation between the current position of the grinding wheel in the axial direction and the X-axis direction and the normal position is calculated, and a command is issued from the computer to correct (offset) the deviation, so that a correct gear can be automatically finished. FIG. 8 shows a gear measuring and NC according to the present invention.
FIG. 5 is a chart showing an automated manufacturing process for determining the positional relationship between a grinding wheel and a gear to be machined using a gear grinder with a gear, and finally finishing the gear to be machined. In the present invention, it is possible to correct the current grinding machine from the gear measurement data, for example, to correct the displacement of the position of the grinding wheel shaft and the work shaft due to temperature rise, and to operate the gear grinding machine in a correct state at all times. .

[0018]

As described above, according to the present invention, the gears are ground on the gear grinding machine immediately after the ground gears are left as they are, that is, with the grinding wheel and the work gear mounted on the gear grinding machine. The measurement can be started, and the control of each axis for the measurement can be controlled by using the function originally provided as the gear grinding machine with NC. Since it is not necessary to add a new control function or change the mechanical part of the grinding machine for measurement, it is possible to obtain an inexpensive, highly versatile and compact gear grinding machine with a gear measuring function. After rough grinding of the gears, the gears are measured, and the grinding operation is corrected again based on the results, so that the finish grinding can be performed. Therefore, the automation and efficiency of high-precision gear manufacturing can be improved. In particular, it is difficult to correct the temperature displacement of a conventional high-precision gear grinder, and it requires a considerably long running-in operation, requires a high-temperature chamber, or uses a material such as a casting with a small coefficient of thermal expansion. Although the method has to be dealt with, a gear with extremely high precision can be easily obtained by relatively rough temperature control. Further, applicable gears are not limited to involute gears, and many other effects can be obtained such as application to measurement of a curved plate of a cyclo reducer (registered trademark).

[Brief description of the drawings]

FIG. 1 is a front view of an NC gear grinding machine to which the present invention is applied.

FIG. 2 is a side sectional view taken along the line AA of FIG. 1;

FIG. 3 is a side view of a grindstone holder to which a probe according to one embodiment of the present invention is attached.

FIG. 4 is a side view showing an example of a method for positioning the tip of the tracing stylus according to the present invention.

FIG. 5 is a diagram showing a measurement principle of tooth profile measurement of an involute gear according to an example of the present invention.

FIG. 6 is a diagram illustrating a measurement principle of tooth profile measurement according to another example of the present invention.

FIG. 7 is a schematic view showing a principle of measuring a gear pitch according to an example of the present invention.

FIG. 8 is a chart showing a gear automatic manufacturing process when a gear is finally finished by the gear grinding machine with gear measuring and NC according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 column 4 Z-axis servo motor 5 Z-axis table 6 B-axis servo motor 7 Grinding wheel holder 8 Grinding wheel spindle motor 9 Grinding wheel 12 Y-axis servo motor 13 Indexing stand 14 Tailstock 15 A-axis servo motor 16 X-axis servo motor 20 X Axis table 21 Body bed 22 Probe holding arm 23,26,27 Probe 24,25 Stopper 28 Detector

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B23Q 17/00-23/00 B23F 23/12 G01B 5/16

Claims (5)

(57) [Claims] 1. A stylus is attached to a grindstone holder of a gear grinding machine with NC, and the stylus direction is set along a tangent to a base circle while contacting the measuring stylus with a tooth surface of a gear mounted on the gear grinding machine.
Wherein simultaneously controlling the rotation about the axis of the wheel holder of movement and the gear, the gear measurement method and performing tooth profile measurement of the gear from the shake in between the measuring element to move. 2. A tracing stylus is attached to a grindstone holder of a gear grinding machine with NC, and theoretical Y and Z coordinate values are obtained for a plurality of points on a theoretical tooth profile curve of a gear mounted on the gear grinding machine. , And the gear fixed to the gear grinding machine
Then, the contact point is brought into contact with the tooth surface of the gear to measure the actual Y and Z coordinate values of each point, and the difference between the theoretical Y and Z coordinate values and the actual Y and Z coordinate values is used to calculate the gear of the gear. A gear measuring method characterized by measuring tooth profile accuracy. 3. A stylus is mounted on a grindstone holder of an NC gear grinding machine, and the stylus contacts the tooth surface of a gear mounted on the gear grinding machine while corresponding to a torsion angle of a tooth trace of the gear. gear measurement method is characterized in that the rotation and movement of the gear axis of the gear at the lead by made to the gear to measure the tooth trace. 4. A stylus is attached to a grindstone holder of an NC gear grinding machine so as to contact a tooth surface of a gear mounted on a gear holding portion of the gear grinding machine, and the stylus is mounted on a gear grinding machine. Sometimes it is possible to retreat to a position that does not interfere with the gear and the grinding wheel, and the tracing stylus is pivotally attached to the grinding wheel holder and
Measuring element capable of tilting backward from the position facing the gear
Held by a holding arm, the probe confronted the gear
Stopper hand for positioning the tracing stylus holding arm in position
A gear measuring and gear grinding machine, wherein a step is provided on the whetstone holder . 5. A pair of measuring elements are attached to a grindstone holder of an NC gear grinding machine so as to contact a tooth surface of a gear mounted on a gear holding portion of the gear grinding machine.
It is possible to retreat to a position that does not interfere with the gear and the grinding wheel during gear grinding, and furthermore, the forward position of the grinding wheel holder during gear pitch measurement is brought into mechanical contact with the grinding wheel holder.
A gear measuring / combining gear grinding machine, wherein a detector for detecting the temperature is provided on the gear grinding machine.