JPH05111851A - Gear measuring method and gear grinder commonly used for gear measurement - Google Patents

Abstract

PURPOSE:To enable easy and accurate measurement without adding new control function for measurement by controlling a probe attached to a stone holder so that it is moved in contact with a tooth surface of a gear for tooth shape measurement from deflection of the probe. CONSTITUTION:In a gear grinder with NC, a grinding wheel 9 formed in the shape of a tooth groove of a gear to be ground is supported by a stone holder 7, and the grinding wheel 9 is rotated and driven by a wheel spindle motor 8. Here, a probe 23 such as an electric micrometer is attached to the stone holder 7 through a holding arm 22. Also, stoppers 24 and 25 for defining the measurement position and the storage position of the holding arm 22, respectively, are provided at the stone holder 7. By this constitution, the probe 23 is moved along the contact point of a base circle in contact with a tooth surface of the gear, and the stone holder 7 and the gear are controlled at the same time. And the tooth shape of the gear is measured based on deflection of the probe 23.

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 with NC, and more particularly to a gear grinding and grinding process for a gear with a grinding wheel and a gear for measuring gears with NC capable of performing gear measurement without removing the gear from the position during grinding. Regarding grinders.

[0002]

2. Description of the Related Art Normally, at least one high-precision gear that is ground by a gear grinder is inspected for tooth profile, tooth trace, etc. in a processing lot to determine whether or not the processing setting conditions are correct. , Processing the rest of the lot after making sure it is correct. Conventionally, the measurement of gear accuracy in this type of gear grinding machine is performed on a dedicated gear measuring machine, but there is one that allows gear measurement on the gear grinding machine as it is after grinding to improve workability. It is being developed. For example, as disclosed in Japanese Patent Laid-Open No. 1-92232, a gauge head of a detector fixed to a grindstone bed with a ground work gear attached to a work spindle of a gear creation machine is attached to a tooth surface of the gear. Detect the tooth profile accuracy by bringing them into contact with each other and rotating the spindle gear and lateral feed of the spindle stock to cause the workpiece gear to make a basic circular rolling motion and input the output signal of the detector to a separately provided measurement control device for data processing. What to do has already been proposed.

[0003]

In the method of checking the accuracy of gears by using a dedicated gear measuring machine after the gears have been machined, it takes time to change the work pieces and set up the settings.
On the other hand, in the gear processing machine with the gear measurement function described above, the types of gears that can be applied are limited, as well as a mechanism for rolling the measured gear and a measurement control device and arithmetic device for processing the output signal of the detector. Need to be added separately,
There is a problem of high cost.

The present invention utilizes the original function of an NC gear grinding machine, and is capable of measuring the accuracy of a gear after machining on an NC gear grinding machine without adding a new control function for measurement. It is to provide a gear grinding machine that also serves as a measurement method and gear measurement.

[0005]

In the gear measuring method according to the present invention, a tracing stylus is attached to a grindstone holder of an NC gear grinding machine, and the control function of each part provided in the NC gear grinding machine is adjusted as necessary. The gear tooth profile, the tooth trace, the gear pitch, etc. of the gear are measured on the NC gear grinding machine.

Further, in the gear grinder for combined gear measurement according to the present invention, a stylus is mounted on a grindstone holder of a gear grinder with NC so that the contact point comes into contact with the tooth surface of the gear mounted on the gear holder of the gear grinder. In addition, the probe can be attached and retracted to a position where it does not interfere with the gear and the grinding wheel during gear grinding.

[0007]

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 a gear grinding machine with NC according to an embodiment of the present invention, and FIG. 2 is a side sectional view taken along the line AA of FIG. The X-axis table 20 is mounted on the T-shaped main body bed 21, and the indexing base 13 and the tailstock 14 are further axially centered (A-axis) on the X-axis table 20.
And the work gear (Fig. 1, Fig. 2
(Not shown) is loaded. The X-axis table 20 is moved by the X-axis servomotor 16 on one side of the bed via the ball screw shaft 18 and the ball screw nut 17 in the left-right direction (X-axis table).
It is reciprocally movable in the axial direction), and the gear holding portion of the indexing table 13 is indexed and rotated around the axis by the A-axis servomotor 15. A column 1 which can be moved forward and backward in the front-rear direction (Y-axis direction) by a Y-axis servomotor 12 is mounted at the center of the rear part of the T-shaped bed 21 via a ball screw shaft 10 and a ball screw nut 11, and in front of this column 1. Similarly, a Z-axis table 5 which is movable in the vertical direction (Z-axis direction) by a Z-axis servomotor 4 above the column via a ball screw shaft 3 and a ball screw nut 2 is mounted. Further, on the front surface of the Z-axis table 5, a grindstone holder 7 is provided.
Is mounted, and a grindstone wheel 9 formed in the shape of the tooth groove of the gear to be cut is pivotally supported on the grindstone holding base 7. 8 is a grinding wheel 9
It is a grindstone spindle motor that drives to rotate. The grindstone holding base 7 is swung on the Z-axis table 5 by a B-axis servomotor 6 held on the Z-axis table 5 about a horizontal axis (B-axis) passing through the grindstone axis center perpendicular to the axis of the A-axis. It is possible. Therefore, when the work gear is a helical gear, the grindstone holding base 7 (grinding wheel 9) can be tilted by an amount corresponding to the twist angle of the gear. When the B-axis servomotor 6 is not used, the grindstone holding base 5 may be manually tilted around the B-axis.

In the case of gear grinding, the gear to be cut is indexed by the indexing table 13
And the tail stock 14 are engaged with the grinding wheel 9, and the X-axis servomotor 16 moves the gear to be ground in the tooth width direction for grinding. When the grinding of one tooth groove is completed, the gear to be cut is rotated by one pitch by the servo motor 15 connected to the indexing table 13 to grind the next tooth groove.
In the case of cutting at the time of grinding or crowning a gear to be cut, the Y-axis servomotor 12 and the Z-axis servomotor 4 control the movement of the grinding wheel 9 in the Y-axis direction and the Z-axis direction. When forming and modifying the grinding wheel, a dresser may be mounted between the indexing table 13 and the tail stock 14 instead of the gear to be machined, and the simultaneous control of each axis can be performed on the main grinding machine. This is disclosed in Japanese Patent Application No. 2-214154.

A gear measuring and gear grinding machine according to an embodiment of the present invention is constructed by mounting a measuring element such as an electric micrometer on the above-described NC gear grinding machine capable of simultaneously controlling at least three axes. FIG. 3 is a side view of the grindstone holding base 7 to which the tracing stylus according to one embodiment of the present invention is attached. Grindstone holding stand 7
Although it is the same as that described with reference to FIGS. 1 and 2, the base end of the roughly L-shaped probe head holding arm 22 is pivotally attached to the side of the grindstone holding base adjacent to the grindstone 9. A measuring element 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 shown by the solid line position in the drawing extends toward the gear to be cut to a storage position (shown by a broken line) flipped upward, A stopper 24 that comes into contact with the back of the arm 22 is provided on the side of the grindstone holding base 7 to position the arm 22 during measurement. Similarly, a stopper 25 is also provided on the upper surface of the grindstone holding base 7 in order to determine the storage position of the tracing stylus holding 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 contact point holding arm 22 is raised to the storage position so that the repeat accuracy is set to about 0.5 μm. Will be easier.

As shown in FIG. 4, the tip end position of the tracing stylus 23 with respect to the gear shaft center (A axis) is such that a cylindrical body 30 (work arbor, center spindle, etc.) having a known radius is mounted between the tail stock 14 and the indexing base 13. Position. Note that 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 diagram showing the measurement principle of the tooth profile measurement of the involute gear according to an example of the present invention. Each movement of the Y-axis table and the Z-axis table and A of the indexing table
The tip end 23a of the tracing stylus 23 is moved along the tangent line PT of the gear basic circle C from the point A to the point B in the figure by simultaneously controlling the axial rotations of three axes. The deflection of the tip 23a of the probe 23 at that time is output as data. In this case, the control program for each axis necessary for grinding the gear to be cut can be used. When the movement of each part is correct and the gears are in accordance with the theory, the deflection of the probe 23 becomes zero. Set the coordinates of point A in the figure to (Y
A, ZA), the coordinates of point B (YB, ZB) are YB =
YA + Lsin θ ₁ , ZB = ZA + L cos θ ₂ , θ =
tan αB-tan αA. However, L is the moving distance of the probe tip 23a 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 by the rotation of the gear 31 on the A-axis.
The tooth profile of one tooth surface 31a is measured. When the tooth profile measurement for one tooth is completed, the gear 31 is indexed and rotated by one pitch, the tip 23a of the tracing stylus is returned to its original position, and the next measurement is started. rg is the radius of the basic circle.

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 biaxial control of the A-axis and the Z-axis. If θ ₁ = θ ₂ + αA = 90 °,
Measurement can be performed by biaxial control of the A axis and the Y axis without moving in the Z direction.

In addition to the tooth profile measurement example based on the principle of FIG. 5, the present invention may employ a method in which the coordinates of the tip of the probe are followed by NC control while the probe is in contact with 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, and one tooth surface is divided into several arcs and the probe is moved to follow the arc. Let In this method, since the contact position of the tip of the tracing stylus changes, the tool diameter is similarly corrected by the attached NC device.

FIG. 6 is a diagram showing a measurement principle according to still another example of the tooth profile measurement according to the present invention. In this embodiment, the measuring element is applied to the tooth surface 31a of the gear 31 by NC control to read the coordinate value of that point. Specifically, 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 and the actual Y
-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. In this case as well, the tip of the probe 2
Since the contact position of 3a changes, it is necessary to correct the tool diameter using the program of the NC device. This embodiment can be applied to any of cycloid gears, trochoid gears, and involute gears.

Next, gear measurement other than the tooth profile will be described. FIG. 7 is a schematic diagram showing the principle of measuring the gear pitch.
A pair of stylus 26, 27 such as an electric micrometer is attached to the front surface or the side portion of the grindstone holding base 7, and the grindstone is held on a portion immovable in the Y-axis direction, specifically, on the side portion of the X-axis table 20. A detector 28 such as an electric micrometer for detecting the forward position of the platform 7 is pivotally mounted. In the present embodiment, the pair of gauge heads 26 and 27 are pitch circles 29 of the gear 31.
The distance between them is set so as to contact the upper tooth surfaces 31a and 31b. The pitch of the gears is measured by both measuring elements 26, 27.
Obtained from reading. As the measurement procedure, first, the grindstone holding base 7 is moved forward 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 base (at this time, Y- Z coordinates are Y ₀ and Z ₀ ), and the grindstone holder 7 is in the Y-axis direction (direction away from the gear).
Retreat to. Next, the A-axis is rotated by one pitch, and the grindstone holding base 7 is again moved forward in the Y-axis direction to be positioned at the Y ₀ position. At this time, it is checked by the detector 28 on the X-axis table 20 whether the position of the grindstone holding base 7 has correctly returned to the Y ₀ position. A single pitch error can be obtained by displaying the difference between the readings of the two measuring elements 26 and 27 at this time. This operation is repeated N times or 360 °. According to this method, since the difference between the pair of measuring elements is taken, the indexing error of the A axis does not enter into the measuring error. The cumulative pitch error and the adjacent pitch error can be obtained by taking in the data of each probe and processing the data.

In the case of a tooth line inspection, 1 of the tooth surface of an arbitrary tooth
It is sufficient to apply a tracing stylus to a point and move it in the tooth width direction (X axis direction) and at the same time rotate the A axis by the lead angle (in the case of a helical gear). Also in this case, if the precision of the grinder is high and the gear is ground according to the theory, the runout of the probe becomes zero. In the case of a helical gear, two-axis simultaneous control of the X-axis and the A-axis is performed as described above, but in the case of a spur gear, movement only in the X-axis direction is required.

For the above-mentioned various measurements, an electric micrometer or the like can be used to obtain data as electric signals. Therefore, it is possible to automatically judge whether the gear accuracy is good or bad based on the result obtained by taking these data into the computer. Furthermore, data processing is performed on the measurement results of the tooth profile and tooth trace, and Y
It is possible to automatically calculate the correct gear by calculating the deviation between the current position of the grinding wheel in the axial direction and the X-axis direction and the normal position and issuing a command from the computer to correct (offset) the deviation. FIG. 8 is an NC for measuring gears according to the present invention.
FIG. 6 is a chart showing an automated manufacturing process in which the positional relationship between the grinding wheel and the gear to be worked is obtained by using the attached gear grinder, and the gear to be finished is finally finished. In the present invention, conversely from the measurement data of the gear, the correction of the grinding machine at the present time, for example, the displacement of the position of the grindstone shaft and the work shaft due to the temperature rise is corrected, and the gear grinding machine can always be operated in a correct state. ..

[0018]

As described above, according to the present invention, the gear after grinding is left as it is, that is, the grinding wheel and the gear to be machined are mounted on the gear grinding machine, and the gear is immediately moved 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 possessed by the NC-equipped gear grinding machine. Since it is not necessary to newly add a control function or change the mechanical part of the grinding machine for measurement, it is possible to obtain a gear grinding machine with a gear measuring function which is inexpensive, highly versatile and compact. After the rough grinding of the gears, the gears are measured, and the grinding operation is corrected again based on the result, so that the finish grinding can be performed, so that the automation and the efficiency of the high-precision gear manufacturing can be achieved. Especially, it is difficult to correct the temperature displacement of the conventional high-precision gear grinding machine, and it requires a fairly long run-in operation and a high temperature chamber, or the use of materials such as castings with a small coefficient of thermal expansion. Although it had to be dealt with by a method, the present invention makes it possible to easily obtain a highly accurate gear with relatively rough temperature control. Further, the applicable gear is not limited to the involute gear, and many effects can be obtained such as being applicable to the measurement of the curved plate of the cyclo speed reducer (registered trademark).

[Brief description of drawings]

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

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

FIG. 3 is a side view of a grindstone holding base to which a tracing stylus according to an 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 probe 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 showing a measurement principle of tooth profile measurement according to another example of the present invention.

FIG. 7 is a schematic diagram 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 production process in the case of finally finishing a gear with the gear measuring and NC gear grinder according to the present invention.

[Explanation of symbols]

 1 Column 4 Z-axis Servo Motor 5 Z-axis Table 6 B-axis Servo Motor 7 Grindstone Holding Table 8 Grindstone Spindle Motor 9 Grinding Wheel 12 Y-axis Servo Motor 13 Indexing Table 14 Tailstock 15 A-axis Servo Motor 16 X-axis Servo Motor 20 X Axis table 21 Main body bed 22 Stylus holding arm 23, 26, 27 Stylus 24, 25 Stopper 28 Detector

Claims (7)

[Claims] 1. A measuring element is attached to a grindstone holder of a gear grinding machine with NC so that the measuring element moves along a tangent line of a basic circle while contacting the tooth surface of a gear mounted on the gear grinding machine. A method for measuring gears, characterized in that the movement of the grindstone holder and the rotation of the gears about their axes are simultaneously controlled, and the tooth profile of the gears is measured from the runout of the contact point. 2. A measuring element is attached to a grindstone holder of an NC gear grinding machine, 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 at each point. The actual Y, Z coordinate value of each point is measured by bringing the measuring element into contact with the tooth surface of the gear, and the tooth profile accuracy of the gear is calculated from the difference between the theoretical Y, Z coordinate value and the actual Y, Z coordinate value. A method for measuring gears, characterized in that 3. A gauge head is attached to a grindstone holder of an NC gear grinding machine, and the gauge head is brought into contact with a tooth surface of a gear mounted on the gear grinding machine to cope with a helix angle of a tooth trace of the gear. A method for measuring a gear, wherein the lead is used to rotate the gear and move the gear in an axial direction of the gear to measure a tooth trace. 4. A grindstone holder of an NC gear grinding machine is equipped with two measuring elements, and the forward movement of the grindstone supporting table causes each of the measuring elements to be mounted on a pitch circle of a gear mounted on the gear grinding machine or its A gear measuring method, comprising contacting a tooth surface in the vicinity to measure a gear pitch, and indexing and rotating the gear shaft while the grindstone holding table is in a backward moving state. 5. A grindstone holder of an NC gear grinding machine is equipped with a measuring element so as to come into contact with a tooth surface of a gear mounted on the gear holding section of the gear grinding machine, and the measuring element is gear-ground. A gear grinder capable of both measuring gears and being capable of retracting to a position where it does not interfere with the gears and the grinding wheel. 6. A pair of measuring elements is attached to a grindstone holder of an NC gear grinding machine so as to come into contact with a tooth surface of a gear mounted on the gear holding section of the gear grinding machine, and the measuring element is
A gear that is capable of retreating to a position that does not interfere with the gear and the grinding wheel during gear grinding, and further provided with a detector on the gear grinding machine that detects the forward position of the grindstone holding base during gear pitch measurement. Gear grinding machine for both measurement and measurement. 7. The tracing stylus holding arm is pivotally mounted on the grindstone holding base and is held by a tracing stylus holding arm which is tiltable rearward from a position facing the gear. A gear grinding machine that also serves as a gear measurement according to item 6 or 6.