JP7529607B2 - Gear phase gear inspection device and phase difference measuring method - Google Patents

Description

The present invention relates to a phase gear inspection device and a phase difference measurement method for measuring the phase difference between at least two gears attached to the same shaft, and in particular to a phase gear inspection device and a phase difference measurement method suitable for when the attached gears are helical gears.

Gear shafts with at least two gears, for example two, of the same or different diameters attached to the same shaft are used in various gear mechanisms such as transmissions and differential gear devices. Among these, in gear devices with phase gears in which two gears attached to the same shaft mesh simultaneously, the circumferential positions of the teeth of each gear, i.e., the phases, must be aligned to a specified phase so that the gears can mesh without any problems.

In gear devices, in order to reduce vibrations, noise, and gear wear that occur when the teeth of two meshing gears mesh, helical gears are sometimes used, in which the tooth trace direction of each gear is a line that is inclined relative to the axis rather than a straight line parallel to the axis. When helical gears are used, the tooth trace is not parallel to the axis, so the phase changes depending on the position of each gear in the tooth width direction. For this reason, an efficient method of detecting and adjusting the phase that shortens the preparation time for measurement is required.

In Patent Document 1, in order to realize a gear measuring instrument that can measure in a short time during processing in a phase gear consisting of large and small straight gears attached to the same axis, a dial gauge is placed on the teeth of the large gear and a probe with a spherical tip is placed on the pinion. The probe and dial gauge are movably held by an integrated member, thereby detecting the phase difference between the large gear and the pinion.

Patent Document 2 discloses a configuration in which a pair of spheres with spherical tips are inserted into the tooth grooves at a distance in the tooth width direction in order to evaluate the strength of a gear. A temperature sensor is embedded inside the sphere, and the diameter of the sphere is set to an outer diameter that passes between the tips of adjacent teeth but contacts the tooth surface before reaching the tooth base. This defines the position of the sphere between the teeth, and the center of the sphere coincides with the center of the tooth base.

Patent document 3 discloses a method of synchronizing the movement of a sensor that measures the pitch and/or concentricity of a gear with the rotation of the gear. In this publication, a pair of sensors are inserted between the teeth of a rotating gear to perform measurements, and the sensors are retracted from between the teeth before the next gap between the teeth rotates. In addition, patent document 4 discloses that in the case of a helical gear, in order to accurately determine the start point of the rolling process relative to the machine center, a correction counter that is activated by the machine center is activated when a count value based on the probe radius and helix angle reaches a predetermined value.

Utility Model Publication No. 60-158102 JP 2009-236762 A U.S. Patent No. 4,457,074 Japanese Unexamined Patent Publication No. 57-132016

In the phase gear measuring device described in Patent Document 1, a spherical probe that can move in the tooth trace direction is placed between the teeth of a pinion attached to the same shaft, and an indicator with a dial gauge arranged on the same line as the probe is placed on the tooth surface of the gear. When detecting the phase difference between the gear and pinion, the positions of the indicator and probe are adjusted for a master gear and pinion set that have been created with high precision in advance, and set so that they are placed in contact with the tooth surfaces of the gear and pinion to be tested in the adjusted state. The phase difference is then found from the difference between the indicator reading on the master and the indicator reading on the test gear.

In the measuring device described in this publication, both the gear and the pinion are straight teeth, so the phase difference between the gear and the pinion is almost the same no matter where the measurement is performed in the tooth width direction. Therefore, when setting the measurement state of the master to the gear to be tested, there is no complexity in terms of phase in terms of reproducibility. In contrast, in the helical gears that are the subject of this invention, the phase changes in the tooth width direction, so if the tooth width direction position is not accurately reproduced, the influence of the helical tooth's twist angle will occur. Even though such complicated settings are not required, the measuring device in Patent Document 1 takes time to measure, and it is required to be able to measure even helical gears in a short time. Furthermore, since the indicator is a dial gauge type and measurements are performed manually, the measurement results tend to include personal differences between the measurers. In addition, the minimum unit of measurement is about 1/100 mm, so the measurement accuracy is not sufficient.

Patent Document 2 describes inserting a spherical probe between two adjacent teeth of a gear and abutting the probe against the tooth surfaces of both teeth. This device places two probes at an interval in the tooth trace direction of the same straight gear, making it possible to evaluate the strength of the gear, but it is not possible to measure two different gears simultaneously. When measuring the phase difference of a phase gear in which multiple gears are attached to the same shaft, it is necessary to measure multiple gears at the same time.

In Patent Document 3, two probes are brought into contact with different tooth surfaces of the same gear in synchronization with the rotation of the gear to detect the gear pitch error. In this device, each spherical probe is brought into contact with only one tooth surface of a different tooth of the same gear, i.e., only two different locations, to automatically measure the pitch error. However, this is measurement at two different locations on the same gear, and does not take into consideration the possibility of measuring the phase difference between gears by measuring different gears simultaneously.

Patent Document 4 also describes digital measurement of helical gears. Specifically, a spherical probe is moved along the tooth trace, and the amount of movement of the probe is digitized relative to the angle that is the circumferential movement of the helical gear to determine the helical angle of the helical teeth with high precision. The measuring device described in this publication measures the phase of a helical gear, but in order to simultaneously measure the phases of two helical gears, two devices are required and the relationship between the devices must be determined in advance.

The present invention was developed in consideration of the above-mentioned problems of the conventional technology, and aims to make it possible to measure the phase shift between two helical gears attached to the same shaft with high accuracy and in a short time. In addition to the above-mentioned objectives, another object of the present invention is to make it possible to continuously and automatically measure the phase difference between two helical gears attached to the same shaft in assembly line production, batch production, etc.

The feature of the present invention for achieving the above object is that in a phase gear inspection device for measuring the phase difference between two gears on a gear shaft having at least two gears attached to the same shaft, the device comprises a first probe having a spherical first contact at its tip that can move in and out between the teeth of one of the two gears to be measured, a second probe having a spherical second contact at its tip that can move in and out together with the first probe between the teeth of the other of the gears to be measured, first to fourth links that convert the movement of the contacts of the first and second probes into displacement amounts in two different directions, and first to fourth detection means connected to the first to fourth links, respectively, and a calculation and control device that calculates the phase difference between the one gear and the other gear based on the output of the first to fourth detection means.

In this feature, it is preferable that the one and the other gears are helical gears, and the first to fourth detection means are all electric micrometers. It is also preferable that an air vibrator is provided to drive the first and second probes, the air vibrator is connected to the first and second probes via a drive link, and the calculation and control device abuts the first contactor against both adjacent tooth surfaces of the one helical gear and the second contactor against both adjacent tooth surfaces of the other helical gear via the drive link.

In the above features, it is preferable that the two different directions are two perpendicular directions in a plane perpendicular to the axial direction of the gear shaft, and it is further preferable that the diameters of the first and second contacts are greater than the circumferential gap between the teeth at the tooth base of the one or the other helical gear with which the respective contacts abut, and are equal to or smaller than the circumferential gap between the teeth at the tooth tip.

Another feature of the present invention that achieves the above object is that in a phase difference measurement method for measuring the phase difference between two gears attached to the same shaft, a position where the phases of the two gears coincide is determined in advance, and at the determined position, a first probe having a spherical first contact is moved in and out between the teeth of one of the two gears via a link mechanism so as to abut against both adjacent tooth surfaces, and a second probe having a spherical second contact is moved in and out between the teeth of the other of the two gears so as to abut against both adjacent tooth surfaces, and the displacement amounts in two different directions of the first and second contacts converted into the movement of the link mechanism are detected by first to fourth electric micrometers connected to the link mechanism, and a calculation and control device calculates the phase difference between the one gear and the other gear based on the outputs of the first to fourth electric micrometers.

In this feature, it is preferable that the first and second probes are inserted and removed between the gears of a master gear having two gears manufactured almost identically to the one and the other gears to be inspected, the contacts are brought into contact with both adjacent tooth surfaces of each gear, the displacement amounts of the first to fourth electric micrometers when the contacts with the master are stored, the difference between the displacement amounts detected by the first to fourth electric micrometers for the two gears to be inspected and the stored displacement amount of the master is calculated, and the calculation and control device calculates the phase difference between the one and the other gears to be tested from the difference between the detected amounts of the first to fourth electric micrometers, and it is preferable that both the one and the other gears are helical gears.

According to the present invention, the mounting phase between two helical gears attached to the same shaft is detected by moving a spherical contactor attached to the tip of a link mechanism in and out between the teeth of each gear and abutting against the tooth surface of each adjacent tooth, making it possible to measure the phase shift between two helical gears attached to the same shaft with high precision. In addition, because the movement of the contactor is controlled by a control device via the link mechanism, the phase difference between two helical gears attached to the same shaft can be measured automatically and continuously, even in assembly line or batch production.

1 is a schematic diagram of an embodiment of a phase gear inspection device according to the present invention. FIG. 2 is a schematic diagram illustrating the operation of the phase gear inspection device shown in FIG. 1 . FIG. FIG. 2 is a block diagram of a main part of the phase gear inspection device shown in FIG. 1 . 11A and 11B are diagrams illustrating the contact of a probe with a helical gear. FIG. 13 is a diagram illustrating a phase difference. 4 is a flowchart of a phase gear inspection method according to the present invention.

Hereinafter, an embodiment of the phase gear inspection device according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of the phase gear inspection device 100. The phase gear inspection device is roughly divided into an inspection section on which the workpiece W is mounted and an inspection section that is arranged near the inspection section and includes a plurality of electric micrometers 260 (described later). The workpiece W is a gear shaft having two helical gears, one large and one small, fixedly attached to the same shaft, which is a vertical shaft in this embodiment, with the pinion gear 20 on the upper side and the large gear 30 on the lower side. The large and small gears 30 and 20 are both helical gears with teeth inclined from the axial direction, and the shaft 12 (see FIG. 2A (b)) extending below the large gear 30 is fitted and held by a holding base 42 having a hole formed in the center. The holding base 42 is placed on a base 44, and a jig 52 is erected on one side of the base 44. A centering rod 50 is arranged on the jig 52 to position and hold the tooth tip of the large gear 30. These constitute the part to be inspected.

On the other hand, the inspection unit is provided with first and second probes 310, 310 that can move between the teeth of the large and small gears 30, 20. The first and second probes 310, 310 have spherical first and second contacts (contact balls) 312, 314 at their tips, with the contact 312 coming into contact with the teeth of the small gear 20 and the contact 314 coming into contact with the teeth of the large gear 30, and the diameters (outer diameters) _φd1 , _φd2 of the respective contacts are determined according to the module m of the teeth that constitute the small gear and the large gear. However, since the contacts 312, 314 need to come into contact with both tooth surfaces of the left and right adjacent teeth at the same time, it is geometrically required that φd1, φd2 are larger than the tooth groove width (circumferential groove width) at the tooth bottom of each gear 20, 30 and smaller than the tooth groove width (circumferential groove width) at the tooth tip.

The number of teeth and module vary depending on the design of the phase gear, but for example, the number of teeth of the pinion gear 20 and the large gear 30 are set to be a common divisor. When the number of teeth of the pinion gear 20 and the large gear 30 have a common divisor, the phases of the large and small gears 30 and 20 are the same at multiple points in the circumferential direction. This phase gear inspection device 100 utilizes this property to set the reference position for measuring the phase difference.

First and second links 322, 324, each including a plurality of link members, are connected to the opposite contact side of the first probe 310, which detects the phase of the pinion 20. Similarly, third and fourth links 326, 328 are connected to the opposite contact side of the second probe 310, which detects the phase of the gear 30. These first to fourth links 322-328 are formed with complex spatial bends so as not to interfere with each other. However, the pinion contact 312 and the gear contact 314 are initially positioned so as to be included in a plane including the axis 10 of the workpiece W. In other words, in the initial state, the axis of the workpiece W and the centers of the contacts 312, 314 are substantially in the same plane.

The displacement of the first to fourth links 322 to 328 that make up the link mechanism is converted into electrical signals by an electric micrometer 260 (see Figures 2A and 2B) in the measuring unit 200, which will be described later, into two different directional components for each probe 310, 310, specifically into a displacement component in the x direction in which the first and second probes 310, 310 move in and out or forward and backward, and a y direction perpendicular thereto, and transmitted to a control and calculation unit (not shown). The control and calculation unit calculates the phase difference between the large and small gears 30, 20 from the displacement signal of the electric micrometer 260 transmitted.

In order to insert the first and second probes 310, 310 between the teeth of the large and small gears 30, 20, the first and second probes 310, 310 are connected to the links 332, 334 of the drive link 330, and these links 332, 334 are connected to an air vibrator 336. The air vibrator 336 abuts the first and second probes 310, 310 against the tooth surfaces of the large and small gears 30, 20 with a force of a number (N: Newtons).

Next, the details of the operation of the first to fourth links 322 to 328 will be explained using the schematic diagram in Figure 2. Figure 2A (a) is a schematic top view of the main parts of the phase gear inspection device 100, showing the part that detects y displacement. Figure 2A (b) is a schematic front view of the main parts of the phase gear inspection device 100, showing the part that detects x displacement. Figure 2B is a block diagram showing the interrelationships between the links 322 to 328.

First, detection of x-displacement will be described mainly with reference to FIG. 2A(b). In FIG. 2A(b), the left-right direction of the figure is generally the radial direction (r direction), but in the example described below, it is the x direction. The x direction is the direction in which the first and second probes 310, 310 enter and exit the small gears 20, 30 or advance and retreat, and is indicated by the double-headed arrow in the figure. The direction perpendicular to the x direction is the y direction (see FIG. 2A(a)). As described above, a hard spherical contactor 312 with a diameter φd ₁ (φ2 in this embodiment) is attached to the tip of the first probe 310. Similarly, a hard spherical contactor 312 with a diameter φd ₂ (φ2 in this embodiment) is attached to the tip of the second probe 310. A detection means including a link mechanism is stored in the case 202 of the measurement unit 200 shown in FIG. 1.

One end of a first link 322 for detecting x displacement is connected to a side surface of the upper first probe 310. The first link 322 is partially omitted from the illustration because it overlaps with the third link 326, but is configured by connecting a plurality of link members 242, 272, 274, etc. in a manner that bends at a right angle. The link member 272 is common to the link member 244 of the second link 324 for detecting y displacement. Similarly, one end of a third link 326 for detecting x displacement is connected to a side surface of the second probe 310. The third link 326 is configured by connecting a plurality of link members 222, 282, 284, etc. in a manner that bends at a right angle. The link member 282 is common to the link member 224 of the fourth link 328 for detecting y displacement. In the following description, the second probe 310 for a large gear will be described. The first probe 310 has a similar configuration and operates in a similar manner.

The middle part of the vertically extending link member 284 is configured so that it can rotate around the fulcrum 292. That is, for example, when the second probe 310 enters between the teeth of the gear wheel 30, the part of the link member 284 above the fulcrum 292 moves to the left in the figure along with the movement. On the other hand, the part of the link member 284 below the fulcrum 292, to which the counter probe 286 that acts as a counterweight is attached at its tip, moves to the right in the figure.

A counter contact 288 is provided at the tip of the counter probe 286. The counter contact 288 abuts against a rod-shaped moving member (slide piece) 258 that can move in the left-right direction in the figure with almost no friction. The moving member 258 also moves in the x direction in response to the movement of the counter probe 286 in the x direction. The abutting portion 262 of the electric micrometer 260 abuts against the side of the moving member 258 opposite to the side on which the counter contact 288 abuts. Therefore, the movement of the counter probe 286 in the x direction is detected by the electric micrometer 260 as the displacement of the abutting portion 262 of the electric micrometer 260 via the movement of the moving member 258. Here, the relationship between the displacement of the contact 314 of the second probe 310 and the displacement (output voltage) of the abutting portion 262 of the electric micrometer 260 is calibrated in advance using a known means, so only the x-direction displacement of the contact 314 is detected by the electric micrometer 260 separately from the y-direction displacement.

Next, the detection of displacement in the y direction perpendicular to the x direction will be described with reference to Figures 2A (a) and (b). One end of a second link 324 for detecting y displacement is connected to the side of the first probe 310. The second link 324 is configured by connecting a plurality of link members 242, 244, 284, 246, 248, 250, etc. in a manner that bends at a right angle. In this embodiment, the link members 242, 244, 284 are common to the link members 242, 272, 284 of the first link 322 for detecting x displacement, but may be provided separately. Similarly, one end of a fourth link 328 for detecting y displacement is connected to the side of the second probe 310. The fourth link 328 is configured by connecting a plurality of link members 222, 224, 226, 228 and a link member (y-direction finger) 230, etc. in a manner that bends at a right angle. In this embodiment, the link members 222 and 224 are common to the link members 222 and 282 of the third link 326 for detecting x-displacement, but they may be provided separately.

Next, the y-displacement detection mechanism of the second probe 310 that moves in and out between the teeth of the gear wheel 30 will be described in detail. In FIG. 2A(a), the y-direction displacement, which is the movement of the second probe 310 in the vertical direction on the paper, moves the link member 226 arranged in the left-right direction on the paper (x direction) up and down via the movement of the link member 284 arranged vertically, which is possessed by the fourth link 328, in the vertical direction on the paper (y direction).

The end of link member 226 opposite to the end where it is connected to link member 284 is connected to a longitudinal middle portion of link member 228 extending in the vertical direction (y direction) of the paper. One end of link member 228 is connected to a longitudinal middle portion of link member 230 extending vertically, and an abutment plate 232 is attached to the other end.

The abutment plate 232 is abutted by the abutment portion 262 of the electric micrometer 260, and the y-direction displacement of the second probe 310 is converted into the amount of rotation of the electric micrometer 260 about the fulcrum 264 and detected as the y-direction displacement of the abutment plate 232 via the y-direction displacement of the fourth link 328. Here, the relationship between the y-direction displacement of the second probe 310 and the amount of rotation of the abutment plate 232 of the electric micrometer 260 is calibrated in advance by a known method.

The y-direction displacement of the first probe 310 moving in and out between the teeth of the pinion 20 moves the link member 246 up and down through the y-direction movement of the link member 274 of the second link 324. The longitudinal middle part of the link member 248 is connected to the end opposite to the side where the link member 246 is connected to the link member 274. One end of the link member 248 is connected to the longitudinal middle part of the link member (y-direction finger) 250 extending vertically, and the other end is attached to the abutment plate 252. The y-direction displacement of the first probe 310 is detected by the electric micrometer 260 as the y-direction displacement of the abutment plate 252 through the y-direction displacement of the second link 324. Here, the relationship between the y-direction displacement of the first probe 310 and the amount of rotation of the abutment part 262 of the electric micrometer 260 is calibrated in advance by a known method. This calibration is similar to the case of the second probe 310.

The fourth link 328 used to detect the y-direction displacement of the second probe 310 is capable of detecting the y-direction displacement separately from the x-direction displacement. Therefore, as shown in FIG. 2A(b), each member for detecting the x-direction displacement is capable of moving in the y direction. That is, the moving member (slide piece) 258 for detecting the x-direction displacement is provided so as to be movable in the x direction with a leaf spring 294 interposed between the vertically arranged supports 296 and 290. At the same time, it is capable of moving so as to slide between the leaf springs 294 in the front-to-back direction (y direction) in the figure. Therefore, the fulcrum (base) 270 for detecting the y-displacement is connected to the lower support 290, and the third link 326 for detecting the x-direction displacement is displaced in the y direction as a whole with the base 270 as the fulcrum. In order to ensure this movement, the link member (y-direction finger) 230 extending vertically and the support 296 are connected by a y-direction finger folder 298. In this figure, the mechanism for detecting the displacement of the large gear 30 is omitted because it overlaps with the mechanism, but this configuration and relationship is the same for the second link 324 that detects the displacement of the small gear 20 in the y direction and the first link 322 that detects the displacement in the x direction.

The above relationship is shown in a block diagram in FIG. 2B. The contact 312 of the first probe 310 is inserted between the teeth of the pinion 20, and the amount of displacement of the contact 312 from the reference position is measured when the contact 312 is brought into contact with the tooth surfaces of the adjacent teeth. An electric micrometer 260 is connected to the first link 322, which is a link for detecting x-displacement, and the second link 324, which is a link for detecting y-displacement, and the output of each is converted into a displacement by the control/calculation unit 110 of the phase gear inspection device 100. Similarly, the contact 314 of the second probe 310 is inserted between the teeth of the gear 30, and the amount of displacement of the contact 314 from the reference position is measured when the contact 314 is brought into contact with the tooth surfaces of the adjacent teeth. An electric micrometer 260 is connected to the third link 326, which is a link for detecting x-displacement, and the fourth link 328, which is a link for detecting y-displacement, and the output of each is converted to displacement by the control/calculation unit 110.

The control and calculation unit uses the x- and y-directional displacements of each contactor 312, 314 to determine whether the phase difference between the pinion 20 and the gear 30 is within a specified range, based on the relational equation described below. If it is outside the specified range, it is deemed a failure and is either corrected or discarded. If it is within the specified range, it is deemed an acceptable product and proceeds to the next process.

An air vibrator 336 is provided as a drive source for inserting the first and second probes synchronously or individually into the small and large gears 20 and 30, and drives the first and second probes 310 and 310 via the drive links 332 and 334. The air vibrator 336 is also connected to the control and calculation unit 110, and causes the first and second probes 310 and 310 to enter between the teeth of the small and large gears 20 and 30 in response to a command from the control and calculation unit 110.

A method for determining the phase shift from the reference position will be explained using Figures 3 and 4. Figure 3 shows the state in which a contact 312 (314) is inserted between adjacent teeth of the pinion 20 or the gear 30 and abuts against both tooth surfaces, with the solid line showing the reference state and the dashed line showing the actual installation state of the gear 20 (30).

In Fig. 3, in the reference state, which is the position for inspection by the master, the contact 312 with a diameter of _φd1 is in contact with two adjacent teeth of the pinion 20 at contact points _34a1 and _34b1 on the tooth surface. The center of the contact 312 at this time is _O1 . However, the actual center position of the contact 312 moves to _O2 , which is shifted by dx in the x direction and dy in the y direction from the reference center _O1 position, and the contact points with the tooth surface of the pinion 20 also change to _24a2 and _24b2 . The same is true for the gear 30, where the contact points of the contact ₃₁₄ with a diameter of φd2 change from _34a1 and _34b1 to _34a2 and _34b2 . The difference in phase angle at this time is the angle dθ formed by the lines connecting the center of the gear 20 (30) and the centers _O1 and _O2 of the contacts.

The phase relationship when the large gear 30 and the pinion 20 are actually combined is shown in Fig. 4. Fig. 4 is a top view of the set of the pinion 20 and the large gear 30, and shows the deviation from the reference state. In this figure, the positions of the master small and large gears 20 and 30, which indicate the reference state, are omitted, but the line including the center O of the small and large gears 20 and 30 and connecting the center position _OG1 of the contact 312 and the center position _OH1 of the contact 314 indicates the x direction in the reference state.

In Fig. 4, the contact 312 is inserted between two adjacent teeth _20a , _20b of the pinion gear 20, and comes into contact with the teeth _20a , _20b at contact points _24a , _24b on the tooth flanks. At this time, the center of the contact 312 moves along a locus 22 from a position _OG1 in the reference state to _OG2 . The change in phase angle at this time is represented by a deviation angle _ΔθG formed by lines connecting the center positions _OG1 , _OG2 of the contact 312 with the center O of the pinion gear 20. Similarly, in the gear 30, the contact 314 is inserted between two adjacent teeth _30a , _30b of the gear 30, and comes into contact with the teeth _34a , _34b on the tooth flanks. The center of the contact 314 moves on a locus 32 from the position O _H1 in the reference state to O _H2 , and the phase angle changes by a deviation angle Δθ _H of a line connecting the center positions O _H1 and O _H2 of the contact 312 and the center O of the gear 30.

The coordinates of O _G1 are (xg, yg) and the coordinates of O _G2 are (xg+dxg, yg+dyg). Similarly, the coordinates of O _H1 are (xh, yh) and the coordinates of O _H2 are (xh+dxh, yh+dyh). In this case, Δθ _G and Δθ _H are respectively expressed by the following equations.
Δθ _G = tan ^-1 {(yg+dyg)/(xg+dxg)}
Δθ _H =tan ⁻¹ {(yh+dyh)/(xh+dxh)}
Therefore, the phase deviation (angle) Δθ of the large and small gears 30 and 20 from the master is given by:
Δθ=|Δθ _G −Δθ _H |.
If the deviation angle Δθ is larger than a predetermined angle, the combination of the small and large gears 20, 30 is not suitable and must be corrected or discarded. In this embodiment, the threshold value of the deviation angle Δθ is set to 0.2°.

The above inspection method is summarized in a flowchart in Figure 5. Although not shown in Figure 5, first a master with the same specifications as the large and small gears 30, 20 to be inspected is manufactured and attached to the master gear shaft. In this set of master gears, if the combination of the number of teeth of the large and small gears is not mutually prime, there will be a greatest common divisor other than 1, and based on this, the point where the phase matches is determined as the inspection position. Alternatively, the circumferential positions of each contact 312, 314 are determined at positions where the contacts 312, 314 can be inserted between adjacent teeth without resistance. This position remains unchanged in subsequent inspections.

Since the gear to be inspected is a helical gear, if the gears 20, 30 are set as shown in Figure 1, differences in the height direction positions of the contacts 312, 314 will cause errors in the inspection results. For this reason, the height of the inspection target is set to be constant at all times. This can be achieved, for example, by fixing the inspection part in a fixed position in Figure 1 and moving the part to be inspected together with the base 44. The phase gear shaft to be inspected fits into a predetermined position relative to the holding base 42 that holds the base 44 and the phase gear shaft, so the phase gear shaft to be inspected can always be inspected at a constant height position.

In the master gear thus set, the central coordinates O _G1 (xg, yg) of the contact 312 relating to the pinion and the central coordinates O _H1 (xh, yh) of the contact 314 relating to the large gear are measured and stored in a memory means provided in the control/calculation unit 110. After such preparation work, the phase gear shaft including the large and small gears 30, 20, which is the workpiece W, is transported, for example, by a robot hand and held by fitting the shaft portion into a hole in the holding base 42. In this state, it is moved together with the base 44 to the inspection position. The workpiece W is now set at the inspection position (step S510).

To reproduce the positions inspected by the master, the circumferential positions of the upper and lower gears 20, 30 are aligned to the time of the master inspection. This sets the inspection position (step S520). Next, the control and calculation unit 110 controls the air vibrator 336 to insert the upper and lower contacts 312, 314 at the tips of the probes 310, 310 between the adjacent teeth of the small and large gears 20, 30 and bring them into contact with the respective tooth surfaces (step S530).

As the contacts 312, 314 of both probes 310 come into contact with the tooth surfaces of the small and large gears 20, 30, the circumferential displacement of the contacts 312, 314, which is the circumferential positional deviation (displacement) of the small and large gears 20, 30, is separated into two orthogonal components (x, y) and detected by the electric micrometer 260 (step S540).

The phase deviation angles Δθ _G and Δθ _H of the contacts 312, 314 are calculated from the detected displacements of the contacts 312, 314 in the x and y directions using the above formula. The control and calculation unit 110 calculates the deviation angle Δθ (=|ΔθG-ΔθH) between the upper and lower gears 20, 30 from the calculated deviation angles Δθ _G and Δθ _H (step S550).

In step S560, it is determined whether the deviation angle Δθ is equal to or less than a predetermined angle. In this embodiment, the predetermined angle is 0.2°. If the deviation angle is equal to or less than 0.2°, it has been practically achieved that wear and noise generation is suppressed even when the upper and lower gears 20, 30 mesh simultaneously. If the deviation angle Δθ is equal to or less than 0.2°, it is deemed to have passed (step S570) and is transported to the next process using a robot hand or the like. If the deviation angle Δθ exceeds 0.2°, there is a risk of wear and noise generation when the upper and lower gears 20, 30 mesh simultaneously, so it is deemed to have failed (step S580) and is either advanced to a correction process or discarded.

After the deviation angle Δθ has been determined, step S590 determines whether there is a next workpiece W to be inspected. If there is a next workpiece W to be inspected, the process proceeds to step S510, and steps S510 to S590 are repeated. If there is no next workpiece W to be inspected, the process ends.

In this embodiment, which is configured as described above, it is possible to automatically measure the phase difference between phase gear shafts, which have two helical gears attached to the same shaft, reducing measurement errors caused by the person making the measurement. In addition, since an electric micrometer is used, high-precision inspections up to the μm level are possible.

10, 12...shaft, 20...(small) gear (upper gear), _20a , _20b ...(gear) teeth, 22...path, 24, _24a , _24b , _24a1 to _24b2 ...contact point, 30...(large) gear (lower gear), _30a , _30b ...teeth, 32...path, 34, _34a , _34b , _34a1 to _34b2 ...contact point, 42...holding base, 44...base, 50...centering rod, 52...jig, 100...phase gear inspection device, 110...control/calculation unit, 200...measurement unit, 202...case, 222-228...link member, 230...link member (y-direction finger), 232...contact plate, 242-248...link member, 250...link member (y-direction finger), 252...contact plate, 260...electric micrometer, 258...moving member (slide piece), 262...contact portion, 264...fulcrum, 270...base (fulcrum), 272-284...link member, 286...counter probe, 288...case counter contact, 290...support, 292...fulcrum, 294...leaf spring, 296...support, 298...y-direction finger holder, 310...probe, 312...(first) contact (contact ball), 314...(second) contact (contact ball), 322...(first) link (x-displacement link), 324...(second) link (y-displacement link), 326...(third) link (x-displacement link), 328...(fourth) link (y-displacement link), 330...(driving) link, 332...link (for pinion), 334...link (for large gear), 336...air vibrator, d ₁ , _d2 ...(contact) diameter, O...gear center, O1, _O2 ...contact center _{, OG1 , OG2} , _OH1 , _OH2 ...contact center, W...workpiece, Δθ, _ΔθG , _ΔθH ...deviation (angle)

Claims (8)

A phase gear inspection device for measuring a phase difference between two gears of a gear shaft having at least two gears attached to the same shaft,
a first probe having a spherical first contact at its tip and capable of moving in and out between the teeth of one of the two gears to be measured; a second probe having a spherical second contact at its tip and capable of moving in and out together with the first probe between the teeth of the other of the gears to be measured; first through fourth links that convert the movements of the contactors of the first and second probes into displacement amounts in two different directions; and first through fourth detection means connected to the first through fourth links, respectively, and a calculation and control device that calculates a phase difference between the one gear and the other gear based on outputs of the first through fourth detection means. The phase gear inspection device according to claim 1, characterized in that the one and the other gears are helical gears, and the first to fourth detection means are all electric micrometers. The phase gear inspection device according to claim 2, characterized in that an air vibrator is provided to drive the first and second probes, the air vibrator is connected to the first and second probes via a drive link, and the calculation and control device abuts the first contact against both adjacent tooth surfaces of the one helical gear and the second contact against both adjacent tooth surfaces of the other helical gear via the drive link. The phase gear inspection device according to claim 2 or 3, characterized in that the two different directions are two perpendicular directions in a plane perpendicular to the axial direction of the gear shaft. The phase gear inspection device according to any one of claims 2 to 4, characterized in that the diameter of the first and second contacts is greater than the circumferential gap between the teeth at the tooth bottom of the one or the other helical gear with which the respective contacts abut, and is equal to or smaller than the circumferential gap between the teeth at the tooth tip. A phase difference measuring method for measuring the phase difference between two gears attached to the same shaft, comprising the steps of:
a first probe having a spherical first contactor is moved in and out between the teeth of one of the two gears at the determined position via a link mechanism so as to come into contact with both adjacent tooth flanks, and a second probe having a spherical second contactor is moved in and out between the teeth of the other of the two gears so as to come into contact with both adjacent tooth flanks, first to fourth electric micrometers connected to the link mechanism detect amounts of displacement in two different directions of the first and second contactors converted into movements of the link mechanism, and a calculation/control device calculates a phase difference between the one gear and the other gear based on outputs of the first to fourth electric micrometers. The phase difference measuring method according to claim 6, characterized in that in a master gear having two gears manufactured almost identically to the one and the other gears to be inspected, the first and second probes are inserted and removed between the gears to bring the contacts into contact with both adjacent tooth surfaces of each gear, the displacement amounts of the first to fourth electric micrometers when they come into contact with the master are stored, the difference between the displacement amounts detected by the first to fourth electric micrometers for the two gears to be inspected and the stored displacement amount of the master is calculated, and the calculation and control device calculates the phase difference between the one gear and the other gear to be tested from the difference between the detected amounts of the first to fourth electric micrometers. The phase difference measurement method according to claim 6 or 7, characterized in that both the one and the other gears are helical gears.