JP3186976B2 - Gear eccentricity measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an eccentricity measuring method for measuring the eccentricity of a gear.

[0002]

2. Description of the Related Art A conventional method for measuring the amount of eccentricity of a hypoid gear (ring gear and pinion) used in a drive shaft of an automobile is performed by a dedicated manual measuring machine.

For example, as shown in FIG. 3, there is a manual measuring device called a spacing tester. In the measuring method using the spacing tester, a tooth 1b existing at a position of about 180 ° with respect to a tooth 1a to be measured across a rotation center O of the hypoid gear 1 is brought into contact with a stopper 2 for positioning.

At this time, the tooth surfaces of the tooth 1a to be measured and the tooth 1b corresponding to the stopper 2 are in the same rotation direction.

In the measurement, the dial gauge 3 is applied to the tooth surface at the position of the first tooth 1a to be measured, the reading of the dial gauge at that time is reset to 0, and the tooth to be measured and the tooth to be applied to the stopper 2 are sequentially placed. The tooth position at that time is read by the dial gauge 3 while shifting one tooth at a time.

[0006] The difference between the maximum value and the minimum value of the tooth position reading when the gear 1 is rotated once is the tooth deflection, that is, the amount of eccentricity.

For example, if the machining center O 'is eccentric with respect to the rotation center O of the hypoid gear by e, when the dial gauge 3 is applied to the tooth 1a at the diagonal position with respect to the tooth 1b applied to the stopper 2, The value of 2e can be read by the dial gauge 3.

Next, when the gear is rotated by half, the read value of the dial gauge 3 becomes 4e, and the eccentricity e is obtained from this read value.

[0009] Such measurement, performed every time one cog, determine the eccentricity e _n of each tooth, X by the maximum or minimum square method
The amount of eccentricity in the direction and the Y direction is calculated.

On the other hand, a computer numerically controlled gear measuring machine (hereinafter referred to as CNC
Gear measuring machine). This CNC gear measuring machine
It has a function of measuring a pitch error for each tooth for all teeth.

In the measurement of the pitch error, the position error of the gear teeth is determined as the index error of each tooth with respect to the rotation center of the gear. From this result, although the calculated cumulative pitch error is related to the amount of eccentricity of the gear, it also includes other errors and cannot be used as it is as the value of the tooth runout.

Therefore, since the measurement of the tooth runout and the measurement of the pitch error must be measured by separate measuring machines, there is a problem that the center of rotation of the gear differs between the two due to an attachment error to the measuring machine.

[0013]

The conventional manual measuring machine is:
Since the tooth facing the position of about 180 ° was applied to the stopper, the variation of the pressing force was the variation of the measured tooth. In particular, when measuring manually using a measuring device called a spacing tester, the pressing force relied on the hand feeling, and this was a factor that caused the measured values to vary greatly.

For this reason, the spacing tester, which is a manual measuring device, requires skill in setting and measuring a work, has poor repeatability of the measurement, and takes a long time for the measurement.

Further, as described above, the measurement of the tooth runout and the measurement of the pitch error are measured by separate measuring machines, and the number of measuring machines and the measuring operation are useless.

As described above, conventionally, a dedicated measuring device for measuring the tooth runout is required, and since the measurement is performed for each tooth, it takes a long measurement time, and the number of teeth is odd. There are also problems that cannot be measured with teeth.

The present invention has been made in view of the above-described circumstances, and makes it possible to effectively use one computer numerically controlled gear measuring machine to perform highly accurate tooth runout measurement in a short time. It is intended for.

[0018]

According to a first aspect of the present invention, there is provided a method for measuring the amount of eccentricity of a gear with respect to the center of rotation of the gear, the method for automatically measuring the eccentricity of a gear. This is a method for measuring the eccentricity of a gear, which measures the pitch of each tooth by a numerically controlled gear measuring machine to determine the pitch error with respect to the theoretical value, and calculates the tooth runout from the pitch error at diagonal positions. .

According to a second aspect of the present invention, in the gear eccentricity measuring method according to the first aspect, a cumulative pitch error at a diagonal position is determined, and the cumulative pitch error is calculated in a direction perpendicular to the torsion angle of the known tooth. In this method, a value corresponding to the amount of eccentricity in the hypoid gear is obtained by calculation.

According to a third aspect of the present invention, in the method for measuring the eccentricity of a gear according to the first or second aspect, when a predetermined pressure is detected by a detector of the computer numerically controlled gear measuring machine, This is a method of measuring the tooth pitch by reading the rotation angle of the gear with an encoder.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

According to the present invention, a pitch error and tooth runout can be measured simultaneously by a computer numerically controlled gear measuring machine (hereinafter referred to as a CNC gear measuring machine).
It should be noted that the CNC gear measuring machine is not a machine dedicated to pitch measurement, but can also measure the tooth profile and tooth trace of spur gears and helical gears.

The tooth runout is calculated based on the pitch error measurement data by a software program incorporating the following logic.

FIG. 1 shows a functional configuration diagram of the equipment. Reference numeral 1 denotes a gear such as a hypoid gear to be measured, and the gear 1 is fixed by a main shaft 11 and a dog 12.

First, the probe 14 of the detector 13 is inserted into the tooth space of the gear 1.
And set the tip of the tracing stylus 14 on the pitch circle.

Then, when the gear 1 is rotated by the main shaft 11 and the set predetermined pressure is detected by the differential transformer 15, the rotation of the gear 1 is stopped and the rotation angle at that time is read by the rotary encoder 16.

Next, the tracing stylus 14 of the detector 13 is retracted from the tooth space of the gear 1, and the gear 1 is rotated by a predetermined angle to be set at the same position of the tooth space of the next tooth. Read the rotation angle. Such a procedure is sequentially repeated to measure all tooth spaces.

As described above, the rotation angles of the measuring gear 1 read by the rotary encoder 16 are respectively changed by the CNC.
The data is taken into the personal computer of the gear measuring machine and is processed as follows.

FIG. 2 is a conceptual diagram for determining the tooth runout from the above measurement results. In this figure, 2a is a virtual stopper corresponding to the stopper 2 used in the conventional tooth runout measurement.

In FIG. 2, the pitch error of each tooth is obtained from the rotation angle measured by the above-mentioned method and the ideal pitch known in advance from the design data of the gear, with the number of teeth n.

[0031] For convenience of explanation, ₁ each pitch error of from 1 tooth th to n / 2 teeth φ, and _{··· φ n, (n / 2} ) +1
₁ each pitch error from tooth to n teeth theta, When · · · theta _n, deflection [Delta] [phi _i of each tooth on the mutually diagonal positions is calculated by the following formula.

Δφ ₁ = φ ₁ −θ ₁ ... Δφ _i = φ _i −θ _i・ Δφ _n = φ _n −θ _n Therefore, the tooth run-out f to be obtained is the maximum run-out MaxΔ
From φ _i and the minimum shake MinΔφ _i , the following equation can be used.

[0033] f = MaxΔφ _i -MinΔφ _i Here, when n is an even number _{φ i = θ (n / 2} ) + i (i = 1,2, ··· n / 2) or φ _i = θ _{- (n / 2) + i} (i = (n / 2) +1,... n) Further, when n is an odd number, φ _i = θ _{(n-1) / 2 + i} (i = 1, 2, ... ^{(n + 1)}
/ ₂₎ or _{φ i = θ - (n +} 1) / 2 + i (i = (n + 1) / 2 +1, ··
-N) The tooth runout f obtained by this algorithm theoretically matches the tooth runout value obtained by the conventional measuring machine. Correction is made to eliminate the deviation of the rotation center of the gear based on the tooth runout f.

Next, in the case of a hypoid gear, the pitch of each tooth is determined by a CNC gear measuring machine, and the value of each pitch is converted into a value on the circumference and accumulated, thereby obtaining the cumulative pitch at the diagonal position. The error is obtained, and the torsion angle of the tooth of the hypoid gear is a known value. By calculating the above-described cumulative pitch error in the direction perpendicular to the torsion angle of the tooth, the conventional example is shown in FIG. A value corresponding to the amount of eccentricity is obtained.

This measuring method is particularly suitable for measuring the amount of eccentricity of a hypoid gear.
The overall tendency can be determined from the stored pitch error, which can be used to eliminate the deviation of the rotation center of the gear.

In addition, even in the case of the runout of the tooth of a ground or processed product for each tooth surface, such as the grinding of a shaving cutter, measurement is performed before grinding or processing of both tooth surfaces is completed, and the pitch is measured. The error can be grasped.

[0037]

According to the first aspect of the present invention, the function of measuring the pitch of each tooth provided in the computer numerically controlled gear measuring machine is effectively used, and the measured pitch is arithmetically processed. Since the amount of eccentricity can be determined with high accuracy, there is no need to install a conventional measuring machine for eccentricity measurement and a computer numerically controlled gear measuring machine for tooth profile and tooth trace measurement. An accurate amount of eccentricity can be measured only by adding software, and this can be used to eliminate deviation of the rotation center of the gear. In short, it is possible to reduce the number of measuring machines, the number of times of measurement, and the measurement time. Further, since obtained by calculating the deflection from pitch error of the teeth, it is possible to determine the amount of eccentricity number of teeth even in the case of an odd number of teeth.

According to the second aspect of the present invention, the value corresponding to the amount of eccentricity of the hypoid gear can be obtained by calculating the cumulative pitch error in the direction perpendicular to the torsion angle of the known tooth.

According to the third aspect of the present invention, when a predetermined pressure is detected by the detector of the computer numerically controlled gear measuring machine, the rotation angle of the gear is read by the rotary encoder, thereby enabling the conventional manual measurement. Variations in measured values due to variations in pressing force when using a machine can be prevented, and run-out measurement of a gear with high repeatability can be performed in a short time.

[Brief description of the drawings]

FIG. 1A is a plan view showing an embodiment of a gear eccentricity measuring method according to the present invention, and FIG. 1B is a front view thereof.

FIG. 2 is a conceptual diagram for determining tooth runout from a measurement result of a rotation angle of a measurement gear.

FIG. 3 is a principle diagram showing a measuring method using a conventional spacing tester.

[Explanation of symbols]

 1 gear 13 detector 16 rotary encoder

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-135301 (JP, A) JP-A-56-10202 (JP, A) JP-A-5-296760 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G01B 5/00-5/30 G01B 21/00-21/32 G01M 13/02

Claims (3)

(57) [Claims] An eccentricity measuring method of a gear for measuring an eccentricity of a machining center with respect to a rotation center of a gear, wherein a pitch of each tooth is measured by a computer numerically controlled gear measuring machine to determine a pitch error with respect to a theoretical value. A method for measuring the amount of eccentricity of a gear, wherein a tooth runout is calculated from a pitch error at a diagonal position. 2. The method according to claim 1, wherein a value corresponding to the amount of eccentricity of the hypoid gear is obtained by calculating a cumulative pitch error at a diagonal position and calculating the cumulative pitch error in a direction perpendicular to a torsion angle of a known tooth. The method for measuring the amount of eccentricity of a gear according to claim 1. 3. A tooth pitch is measured by reading a rotation angle of a gear by a rotary encoder when a predetermined pressure is detected by a detector of the computer numerically controlled gear measuring machine. Item 3. The method for measuring eccentricity of a gear according to Item 1 or 2.