JPS587923B2 - Hagurumakensahouhoutosouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for measuring and inspecting the performance of a gear, that is, the rotation transmission accuracy and the size and shape of tooth contact when the gear meshes with a master gear.

Conventionally, gear accuracy has been measured by measuring individual gear errors such as gear pitch, tooth profile, and tooth lead.

According to this method, for example, a pitch measuring instrument only needs to measure the pitch, but it is extremely difficult to evaluate the performance of gears based on the measured values obtained. However, it is difficult to determine the relationship between them.

For example, it is not clear at what point on the measured gear curve the pitch was measured, and generally only the tooth profile is measured at four locations at 90° intervals, so it is impossible to determine the rotational transmission error of the gear. It is extremely difficult.

Furthermore, since the relative relationship between adjacent tooth profiles is not determined, it is difficult to examine, for example, whether or not the two pairs of teeth are participating in the meshing correctly, that is, the contact between the teeth, in a two-pair meshing range.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to propose a new method for inspecting gears in which the performance of gears is directly determined, and to provide a gear inspection apparatus for carrying out such inspections.

Moreover, in the gear inspection device according to the present invention, even in the case of a hopped gear, only one tooth may have a particularly large error, so all teeth of the gear to be measured are fully automatically measured. This makes it possible to shorten measurement time and avoid errors caused by operator intervention.

Hereinafter, the present invention will be explained in detail based on the accompanying drawings.

First, considering the gear error in the cross section perpendicular to the axis of a cylindrical gear with an involute tooth profile curve, if we consider the standard involute curve tooth profile at the correct pitch from the base circle Dg as shown in Figure 1, the error of gear G is equal to this standard tooth profile. This appears as the black part in Figure 1.

Therefore, by measuring this black part of all teeth, the error of the gear can be determined.

Now, if we shift a point on the tooth profile where there is a tooth profile error to Q, this point is the length ρ of the tangent drawn from Q to the base circle Dg, and the original line oX
It can be expressed by the angle ξ from to the contact point R of this tangent.

Let Qo be the intersection between QR and the reference involute tooth profile.

R=ρ. Then, the error f of the Nth tooth can be obtained by the following equation.

However, rg is the base circle radius, te is the difference line pitch, and ξ is the central angle from the original line oX to oR.

Furthermore, as shown in the lower part of FIG. 1, if the error f is shown on a vertical line at a distance of ξ or ξ·rg from the starting point S, then
Errors of all teeth are expressed as deviations from the standard involute tooth profile. According to this representation method, the tooth profile errors of all teeth can be displayed on a straight line, and therefore the most The line that connects the protruding lines represents the meshing error of this gear.

Further, as shown in the left part of FIG. 1, two values of tl and d' can be obtained for one ξ' in the range of two pairs of gears.

If ρ′−ρ”>te, only teeth of ρ′ will mesh ρ′
If −ρ′=te, two pairs of teeth mesh simultaneously, ρ′−
When d''<te, the teeth ρ' engage and the teeth ρ' do not.

In this way, using this expression method, it is also possible to examine the state of tooth contact.

A gear inspection apparatus and system according to the present invention for obtaining gear inspection results using the above expression method will be described below.

In the gear inspection apparatus according to the present invention shown in FIGS. 2 to 4, the gear G to be measured is supported by both centers 11 and 13. As shown in FIGS.

The rotating main shaft 15 having the lower center 13 is rotatably held by precision slide bearings 17 and 19, and its runout is kept to a minute amount within 1 [μm].

A worm wheel 21 is attached to the lower part of the rotating main shaft 15, and this worm wheel 21 is precisely ground with a grinding machine and meshes with the involute worm 23 to maintain its rotation transmission accuracy at a high precision of several seconds.

Furthermore, the worm shaft 23a has a pair of screw gears 25, 27 (
Since it is rotated by the pulse motor 29 while being decelerated by the tooth ratio (Z1/Z2), when one pulse is input to the pulse motor 29, the rotating main shaft 15 rotates by a small constant angle of several seconds.

In addition, a precision magnetic disk 31 (accuracy 2", for example) on which a magnetic scale is engraved is attached to the rotating main shaft 15, and since there is a magnetic scale corresponding to, for example, 2160 pulses in one rotation, the rotating main shaft 15
5, the magnetic head 32 reads the magnetic scale and emits one pulse of electrical signal every 10 minutes of rotation angle.

An arm 33 protrudes from this magnetic disk 31, and this arm 33 is attached to a dog 35 attached to a mandrel 37 of the gear G to be measured.
The gear G to be measured can rotate forward and backward integrally with the rotating main shaft 15 and the magnetic disk 31.

That is, the gear G to be measured rotates in the forward or reverse direction together with the rotating main shaft 15 in accordance with the drive in the forward or reverse direction by the pulse motor 29 .

Now, when the gear to be measured G rotates, the measuring stylus 39, which comes into contact with the rotating gear and is advanced by this, moves onto the measuring table 4.
It rests slidably on 1.

A linear magnetic scale 43 is attached to this probe 39, and the magnetic scale 43 has a pitch of, for example, 0.2 (m).
m) is engraved with a magnetic scale, which is detected by a magnetic head 45.

As shown in the figure, the measuring pedestal 39a to which the measuring stylus 39 is attached moves linearly smoothly and accurately with the V-groove and the bearing ball, and the measurement pressure is applied so that the measuring stylus 39 and the gear of the gear to be measured G come into contact with each other. is given by the weight of a light weight (not shown) hanging on the probe 39.

Therefore, during measurement, when the measurement of one tooth is completed from the tooth root to the tooth tip, the measuring stylus automatically falls into the groove of the next tooth.

In addition, in order to find the position of the measurement pedestal 39a when the measuring stylus 39 contacts the pitch point of the teeth, the measurement pedestal 39a has a magnetic material 4.
7 is fixed, and a magnetic sensor 4 is also mounted on the measuring table 41.
9 has been installed.

This magnetic sensor 49 is movable on the measuring table 41.

Note that 50 is a speed detector for the worm shaft 23a.

Next, the entire system of the gear inspection device according to the present invention having the above-mentioned structure will be explained based on FIG.

When inspecting the gear G to be measured, pulses generated from the magnetic disk 31 and the magnetic scale 43 due to the rotation of the rotating main shaft 150 and the movement of the probe 39 are guided to the tooth profile error calculation section 57 via detectors 51 and 52, respectively.

This tooth profile error calculation unit 57 counts the distance actually moved by the measuring stylus 39 each time the gear to be measured G, that is, the main shaft 15 rotates by a certain angle (10 minutes), and presets the preset dial (not shown). Find the tooth profile error by calculating the deviation from the theoretical value for the correct involute tooth profile set to (none).

Therefore, this tooth profile error calculation section 57 can be formed using a known calculation circuit or the like.

In order to automatically measure such tooth profile errors sequentially for all teeth of the gear G to be measured, the main shaft rotation control section 67 connected to the pulse oscillator 65 rotates the rotating main shaft in a predetermined normal direction (during tooth profile measurement). The number of pulses necessary to repeat the reversal (returning the adjacent tooth surface to be measured next to the measurement starting position) is generated and supplied to the pulse motor drive circuit 69.

Spindle rotation angle required to measure one tooth profile (normal rotation)
θp varies depending on the gear G to be measured, and is expressed by the following equation.

θp=cos-1 (Zcosα0/Z+2) where Z, α
.

are the number of teeth and pressure angle of the gear G to be measured.

However, as mentioned above, after the measurement of one tooth is completed, the measuring stylus 39
To automatically enter the next tooth groove, the actual rotating spindle 15
The normal rotation angle ψp must be set slightly larger than the above-mentioned θp.

Further, considering the simplicity of the control circuit of the main shaft rotation control section 67, it is practical to use the following modern formula as the setting value of the normal rotation angle ψp.

ψp=20°+{360°/(Z+S)) On the other hand, the measurement start position φN of the tooth on the N tooth surface of the gear G to be measured is ψN=
(360°/Z)xN, so the rotational movement of the rotating main shaft 150 is as shown in FIG.

What should be especially considered here is that the stop position of the spindle (when moving from forward to reverse or from reverse to forward) must be at a certain angle (64 seconds) from the position where the pulse of the magnetic disk 31 is generated.
This is to prevent unstable magnetic scale pulses from occurring at the start and stop of spindle rotation.

Therefore, although the actual rotation of the main shaft 15 will slightly overrun the value in the above equation, this value is small and there is no problem.

The rotation control described above is performed by a mixed method of closed loop control in which pulses from the magnetic disk 31 are fed back to the spindle rotation control section 67 and closed loop control using only the pulse motor.

Furthermore, this inspection device measures the pitch error of the gear G to be measured at the same time as measuring the tooth profile as described above.

First, in the indexing pulse generator 61, a reversible counter (not shown) counts forward and reverse rotation pulses generated from the magnetic disk 31 of the rotating main shaft 15, and
When measuring the tooth profile of the O-th tooth, HN=(3
A pulse is generated at the position 60°/Z)・N.

The relative deviation between this indexing pulse and the pitch point pulse produced by the magnetic sensor 49 is due to the pitch error.

FIG. 7 shows these relationships. In order to express the relative deviation amount as a displacement on the tangent to the basic circle, the output Hals (1μ/1 pulse) from the detector 53 of the magnetic scale 43 is calculated by the pitch error calculation unit 59. I am counting.

Now, in order to obtain an error curve based on the gear accuracy expression method described above based on FIG.
will be processed.

FIG. 8 is a block diagram of this continuous error curve synthesis section 63.

Now, when the Nth tooth profile measurement is started, the tooth profile error data (7 binary bits + sign bit) is sequentially stored in one of the two memories, for example, RAM-1.

The memory address is specified by counting the pulses of the magnetic disk 31 with the address counter 73, and the address p at the time when the pitch point pulse is generated from the magnetic sensor 49 is specified by the latch 74a.
to be memorized.

During the reversal after the tooth profile error is completed, data X at address p in memory RAM-1 is read out, used as input A of 8-bit Jn calculation a76, pitch error εN is input into input B of adder 76, and the result is calculated. Σ-xpN-εN is stored in the latch 74b.

Further, when the measurement of the (N+1)th tooth of the gear G to be measured is started, the data is stored in the memory RAM-2.

At the same time, the data in the memory RAM-1 is sequentially read out and becomes the data at the input A of the adder 76.

On the other hand, since the input B is connected to the latch 74B, the calculation output becomes ΣBxiN-(xpN~εN).

However, i indicates a memory address.

In this manner, the result of data processing of the Nth tooth is outputted in synchronization with the rotation of the rotating main shaft 15 during the measurement of the N+1th tooth surface.

The error curve group for which these results were obtained for all teeth is N
= expressed as the deviation from the reference involute tooth profile passing through the pitch point of the 0th tooth.

The output can be printed out as a digital quantity using a 7lb printer, or it can be sent to the main shaft 150 via a D-A converter 77.
The pen is written on the chart 71a that moves in synchronization with the rotation.

Next, examples of measurement results obtained using the gear inspection apparatus according to the present invention are shown in FIGS. 9A to 9J.

Figures 9A and 9B show the errors of two gears to be measured that were machined by a hop machine, and when both figures are compared, it can be seen that they show almost the same tendency.

FIG. 9C is a curve showing the rotation transmission error of the gear, which is obtained by connecting the highest points of the error curves shown in FIGS. 9A and 9B.

Figures 9D and 9E are examples of measured gears cut with another hobbing machine, and Figures 9F and 9G are measurement examples of gears cut with another hobbing machine. be.

FIG. 9H shows a measurement example of a gear cut with a gear shaper, and FIGS. 91 and 9J show measurement examples of a gear cut with a gear grinder.

Referring to these figures, measurement results No. 9A and No. 9B show a typical tooth profile for hobbing, with a rotational variation equal to the number of teeth per revolution.

The gear shown in FIG. 9D has a pressure angle error (+4') and shows a variation of 15 times the number of teeth.

The gear shown in Figure 9F has a large pressure angle variation (-14').
, and the unevenness of the hop cut is superimposed.

The gear shown in FIG. 9H has a large pitch error, with fluctuations equal to the number of teeth per revolution.

The gear shown in FIG. 91 was produced by a gear shaping machine with a rack-shaped tool, but only a very small pressure angle error (+3') was observed, the tooth profile was good, and the rotational variation was small.

The gear in Figure 9J is a helical gear made by another gear grinder, and has a good tooth profile with only a slight pressure angle error.

However, there is an error in amplitude of 20 μm. FIG. 10 shows an example of measurement of the tooth profile error of two adjacent teeth measured by the gear inspection device according to the present invention.

Referring to Figure 10, it can be expected that the A, B, F, and G gears will have almost full tooth contact, but the C gear will have some play on the tooth end surface, and the D and E gears will have some tooth contact on the tooth end surface. The hit is strong,
It can be seen that the two pairs of meshing cannot be achieved in either case.

As can be understood from the above measurement examples, according to the present invention, when inspecting gears, it is possible to easily consider the rotational transmission error and tooth contact of the gear G to be measured from the measurement result graph or data. performance can be easily evaluated.

Further, according to the present invention, it is possible to fully automate gear inspection by processing pulse signals emitted from magnetic discs and magnetic scales.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the accuracy expression method of gears according to the present invention,
Fig. 2 is a front view of the gear inspection device according to the present invention, Fig. 3 is a plan view taken along the line ■-■ in Fig. 2;
Figure B is a front view and side view of the device shown in Figures 2 and 3, showing the parts related to the operation of the probe, and Figure 5.
Figure 6 is a block diagram showing the system of the gear inspection device according to the present invention. Figure 6 is a diagram explaining the rotation control of the rotating main shaft.
The figure is a time chart of pitch error detection, Figure 8 is a block diagram showing a configuration example of the continuous error curve synthesis section in the system of Figure 5, and Figures 9A to 9J are measurements taken by the gear inspection device according to the present invention. FIG. 10 is a graph showing an example of a measurement in which the tooth profile error of two adjacent teeth was measured using the gear inspection device according to the present invention. In the figure, G...gear to be measured, 15...rotating main shaft, 21...
... Worm wheel, 23 ... Worm, 29 ... Pulse motor, 31 ... Magnetic disk, 33 ... Magnetic head, 3
9... Measuring head, 43... Linear magnetic scale, 45... Magnetic head, 47... Magnetic body, 49... Magnetic head, 57...
...Tooth profile error calculation unit, 59...Pitch error calculation unit, 61...
... Indexing pulse generation section, 63 ... Continuous error curve synthesis section,
67...Main shaft rotation control unit, 69...Pulse motor drive circuit.

Claims (1)

[Claims] 1. In a gear inspection method, the tooth profile error between the tooth profile of each tooth of the gear to be measured and the reference tooth profile is measured, the pitch error of the gear to be measured is simultaneously measured at the pitch point, and then the tooth profile error of each tooth of the gear to be measured is measured at the pitch point. By adding the pitch error value to the deviation between the tooth profile error value at each point on the tooth profile surface of the measured tooth and the tooth profile error at the pitch point on the tooth profile surface, the above-mentioned for the reference tooth profile that passes through the pitch point of the predetermined tooth to be measured. A gear inspection method characterized in that the tooth profile error of each tooth to be measured is calculated, the calculation results are continuously recorded on recording paper, and the gear transmission error is read. 2. By mounting a gear to be measured on a rotating main shaft to which a magnetic disc on which a precision magnetic scale is engraved is fixed so as to rotate together with this rotating main shaft, the rotation angle of the gear to be measured can be determined by pulses from the magnetic disc. A measuring element that is brought into contact with the tooth profile of the gear to be measured and moves linearly on the measuring table in accordance with the rotation of the gear to be measured; A linear scale with graduations engraved thereon is provided, and the linear momentum of the probe is extracted by the number of pulses from the linear scale, and at the same time when the probe contacts the pitch point on the tooth profile of the gear to be measured, the A pitch point detection device is provided that detects the passing position of the measuring head on the measuring table and generates a pulse, so that the tooth profile error of each tooth of the gear to be measured and the pitch error at the pitch point are calculated simultaneously. A gear inspection device characterized in that it is configured as follows. 3. A gear inspection device according to claim 2, characterized in that forward and reverse rotation of the rotational main shaft is pulse-controlled by driving the rotational main shaft using a reversible pulse motor device.