JP4496879B2 - Method and apparatus for measuring diameter of member having circular peripheral surface - Google Patents

Description

  The present invention is a member having a circular peripheral surface, for example, used when measuring the outer diameter of the inner ring constituting the deep groove type ball bearing at the deepest part of the inner ring raceway or the inner diameter of the outer ring at the deepest part of the outer ring raceway. The present invention relates to an improved diameter measuring method and measuring apparatus. Specifically, the outer diameter of the inner ring or the inner diameter of the outer ring can be accurately measured by reliably positioning the contact element in the deepest portion without applying a large force to the contact element. is there.

  For example, in order to obtain data for use in designing high-performance deep groove ball bearings, the inner diameter of the outer ring raceway formed on the inner peripheral surface of the outer ring constituting the ball bearing or the inner ring formed on the outer peripheral surface of the inner ring It is necessary to measure the outer diameter of the track. Conventionally, those described in Patent Documents 1 and 2 are known as measuring apparatuses used in such a case. 10-11 has shown the measuring apparatus described in patent document 1 among these. In the case of the conventional structure described in FIGS. 10 to 11, the inner diameter of the outer ring 1 constituting the single-row deep groove type ball bearing in which the central axis is arranged in the vertical direction is formed on the inner peripheral surface of the outer ring 1. The outer ring raceway 2 is configured to measure at the groove bottom portion (the portion with the largest inner diameter).

  For this reason, in the case of the conventional structure, three balls 3a, 3b, 3c are abutted against the outer ring raceway 2. Of these balls 3 a, 3 b, 3 c, two balls 3 a, 3 b are supported at the tip of the fixed arm 4, and the remaining one ball 3 c is supported at the tip of the movable arm 5. Then, the movable arm 5 is oscillated and displaced to bring the balls 3a, 3b, and 3c into contact with the groove bottom portion of the outer ring raceway 2, and the amount of displacement of the movable arm 5 in the contacted state is measured. The diameter of the groove bottom portion is calculated from the amount of displacement obtained by the device 6.

  In the case of the conventional structure as described above, no particular consideration is given to bringing the balls 3a, 3b, 3c into contact with the deepest part of the outer ring raceway 2. On the other hand, sliding friction acts on contact portions between the outer ring raceway 2 and the surfaces of the balls 3a, 3b, and 3c. For this reason, in the case of the conventional structure described in Patent Document 1, unless the balls 3a, 3b, 3c are strongly pressed against the outer ring raceway 2, the balls 3a, 3b, 3c There is a possibility that the diameter of the groove bottom portion may be measured in a state where the track 2 is in contact with a portion slightly deviated from the deepest portion. As a result, the measured value is slightly smaller than the actual value.

  If the balls 3a, 3b, 3c are pressed strongly toward the outer ring raceway 2, the contact position of the balls 3a, 3b, 3c can be brought closer to the deepest part of the outer ring raceway 2, but in this case The outer ring 1 is elastically deformed, and the measured value becomes larger than the actual value. Since the required accuracy regarding the measurement of the diameter is extremely high, it is not preferable that an error occurs in the measured value for any cause. In consideration of such a point, it is desired to realize a technique for moving the contact to the deepest portion of the surface to be measured in a state where the contact is lightly brought into contact with the surface to be measured. Patent Document 3 discloses an apparatus for measuring the radial clearance of the cylindrical roller bearing by displacing the outer ring in the radial direction while fixing the inner ring of the cylindrical roller bearing and measuring the radial displacement of the outer ring. Is described. It is conceivable that the invention described in Patent Document 3 is applied to a radial ball bearing and the internal clearance of the radial ball bearing is measured. Since it is not always in contact with the deepest part, it is difficult to accurately measure the internal gap.

Japanese Utility Model Publication No. 5-79412 Japanese Utility Model Publication No. 6-51807 Japanese Examined Patent Publication No. 62-7964

  In the present invention, in view of the circumstances as described above, the contact is moved to the deepest portion of the concave groove having an arc-shaped cross section existing on the surface to be measured in a state where the contact is lightly brought into contact with the surface to be measured. Thus, the present invention has been invented to realize a diameter measuring method and measuring device for a member having a circular peripheral surface, which can accurately measure the diameter of the deepest part of the concave groove.

The method and apparatus for measuring the diameter of a member having a circular peripheral surface according to the present invention includes a member having a circular peripheral surface in which a concave groove having a circular arc cross section is formed on the entire periphery. This is a method and apparatus for measuring a diameter-related dimension at the deepest part of the groove.
In particular, in the method for measuring the diameter of a member having a circular peripheral surface according to claim 1, in a state where a plurality of contacts existing in a single vertical surface are pressed against the bottom surface of the groove, High frequency vibration is applied to the contact portion between each contact and the member having the circular peripheral surface. And the dimension regarding the said diameter is measured after moving the contact part of each of these contacts and the member which has the said circular surrounding surface to the deepest part of the said ditch | groove.

According to a second aspect of the present invention, there is provided a diameter measuring device for a member having a circular peripheral surface, comprising a plurality of contacts, a pressing means, a measuring means, a computing means, and a vibrating means.
A plurality of contacts among them exist in a single vertical plane, and at least one of the contacts can be displaced in the diameter direction of the member having the circular peripheral surface. It is supported.
Further, the pressing means presses the contact member supported so as to be displaceable in the diameter direction of the member having the circular peripheral surface toward the bottom surface of the concave groove.
The measuring means measures a displacement amount of the contact member supported so as to be displaceable in the diameter direction of the member having the circular peripheral surface in the diameter direction.
The arithmetic means obtains the diameter of the member having the circular peripheral surface at the deepest part based on the displacement amount measured by the measuring means.
Further, the excitation means applies an appropriate vibration such as a high-frequency vibration to at least one of the member having the circular peripheral surface and each contactor.

  According to the diameter measuring method and measuring device for a member having a circular peripheral surface of the present invention configured as described above, in a state where a plurality of contacts are in light contact with the surface to be measured, It can be moved to the deepest part of the groove having a circular arc cross section existing on the surface to be measured. That is, if high frequency vibration is applied to the contact portion between each contactor and the member having the circular peripheral surface while pressing each contactor toward the concave groove, the frictional restriction of each contact portion is caused. It will be solved. Then, the contact portion between each contact and the member having the circular peripheral surface moves toward the most mechanically stable position, that is, toward the deepest portion of the concave groove. In this case, since the force for pressing each contact toward the concave groove is small, the member having the circular peripheral surface does not elastically deform. Even if this force is small, the contact The position of the child is stabilized in a state where it reaches the deepest part of the concave groove. Therefore, if the diameter of the bottom of the groove is calculated based on the position of each contact in the stable state, the diameter of the deepest part of the groove can be accurately obtained.

Preferably, when carrying out the diameter measuring device for a member having a circular peripheral surface according to claim 2, a member having a circular peripheral surface is formed as a deep groove on the inner peripheral surface as described in claims 3 and 4. An outer ring or an inner ring constituting a radial ball bearing in which a mold outer ring raceway is formed or a deep groove type inner ring raceway is formed on the outer peripheral surface. Each contact is made up of three balls each having a diameter smaller than twice the radius of curvature of the cross-sectional shape of the outer ring raceway or inner ring raceway.
These three balls have their centers arranged on a single vertical plane, and of these three balls, two upper or lower balls are fixed at the same height position. On the other hand, the remaining one ball is supported below or above the two balls so as to be movable on a vertical bisector with respect to a line segment connecting the centers of the two balls. Then, the measuring means measures the displacement amount of the one ball on the perpendicular bisector.
With this configuration, the diameter of the outer ring raceway or the inner ring raceway provided on the inner peripheral surface of the outer ring or the outer peripheral surface of the inner ring constituting the radial ball bearing can be accurately measured at the deepest portion. That is, even if each of the balls, each of which is a contact, is pressed to the outer ring raceway or the inner ring raceway, the balls are efficiently moved toward the deepest part of the outer ring raceway or the inner ring raceway, The diameter of the deepest part can be measured efficiently and accurately.

Further, when the diameter measuring device for a member having a circular peripheral surface described in claim 2 is implemented, preferably, the frequency of vibration such as high-frequency vibration generated by the vibrating means is set as described in claim 5. And the resonance frequency of a member having a circular peripheral surface or the resonance frequency of the measuring device.
According to this configuration, even if the amplitude of the vibration is kept small, the contact portion between each contact and the concave groove such as the outer ring raceway or the inner ring raceway is directed efficiently toward the deepest portion of the concave groove. You can make it.
Further, when the diameter measuring device for a member having a circular peripheral surface described in claim 2 is implemented, preferably, as described in claim 6, the vibration means is a piezo element.
Since the piezoelectric element can easily obtain vibrations of various frequencies, the contact portions between the contact elements and the concave grooves of the outer ring raceway or the inner ring raceway are effectively vibrated, and the contact portions are formed. It can be moved efficiently toward the deepest part of the groove.

  1 and 2 show a first embodiment of the present invention corresponding to claims 1, 2, 3, 5, and 6. FIG. The present embodiment shows the case where the present invention is applied to measure the inner diameter of the outer ring 1 constituting the single row deep groove type ball bearing at the deepest part of the deep groove type outer ring raceway 2. First, the configuration of the inner diameter measuring device for the outer ring for this measurement will be described. The outer ring raceway 2 is formed at the axial center of the inner peripheral surface of the outer ring 1. In addition, the center of curvature of the outer ring raceway 2 exists in the central portion of the outer ring 1 in the axial direction. Therefore, the deepest part of the outer ring raceway 2 exists in the axially central part of the outer ring 1, and the outer ring 1 has an axially symmetric shape with respect to the deepest part.

  The inner diameter measuring device of this embodiment for measuring the inner diameter of the outer ring raceway 2 formed on the inner peripheral surface of the outer ring 1 at its deepest portion includes three balls 7a and 7b, each of which is a contact. The diameter (outer diameter) of these three balls 7a and 7b is sufficiently smaller than twice the radius of curvature of the cross-sectional shape of the outer ring raceway 2 whose inner diameter is to be measured (for example, 1 to 1.5 times the radius of curvature). Value). When the diameter of each of the balls 7a and 7b is too large, the contact area between the surface of each of the balls 7a and 7b and the outer ring raceway 2 is too large (the contact ellipse is large). It becomes difficult to measure the inner diameter at the deepest part. On the other hand, when the diameter of each of the balls 7a and 7b is too small, the contact area between the surface of each of the balls 7a and 7b and the outer ring raceway 2 is too narrow (the contact ellipse is too small), The partial elastic deformation of the outer ring raceway 2 (the dent generated at the contact portion with the surface of each of the balls 7a and 7b) cannot be ignored. In either case, it is difficult to accurately measure the inner diameter at the deepest portion of the outer ring raceway 2. Further, the diameters of the three balls 7a and 7b are strictly matched (with an accuracy of 10 times the accuracy required for the inner diameter of the outer ring raceway 2 or more).

  Among such three balls 7a and 7b, the two balls 7a and 7a existing on the upper side are installed at the same height position. In other words, the line segment connecting the centers of these balls 7a, 7a is arranged in the horizontal direction. For this reason, in the case of the present embodiment, the fixing arm 4a protrudes from the upper part of the front surface (left surface in FIG. 1) of the measuring apparatus main body 8, and the supporting recesses 9 and 9 provided on both sides of the upper surface of the fixing arm 4a. The balls 7a and 7a are supported and fixed by adhesion or the like.

  On the other hand, the remaining one ball 7b can move on the vertical bisector of the line segment connecting the centers of the balls 7a and 7a below the balls 7a and 7a. It is provided in a state where it can be displaced. For this reason, in the case of the present embodiment, the movable arm 5 a is arranged inside the mounting hole 10 provided in the lower part of the measuring apparatus main body 8. The movable arm 5a supports the base end of the movable arm 5a so as to be swingable about a horizontal axis (not shown). The single ball 7b is supported and fixed to the support recess 9a provided on the lower surface of the tip of the movable arm 5a by bonding or the like. The distance from the horizontal axis to the single ball 7b is made as large as possible so that the ball 7b is displaced in the vertical direction along with the swinging motion around the horizontal axis. Yes. In other words, the axial displacement of the outer ring 1 due to the arc motion is suppressed to a negligible level.

  The vertical displacement of the single ball 7b is measured by the measuring device 6a. Therefore, in the case of the present embodiment, the terminal 11 of the measuring device 6a is brought into contact with the upper surface of the intermediate portion of the movable arm 5a. The vertical displacement of the single ball 7b is the measured value of the measuring instrument 6a, the distance from the horizontal axis pivotally supporting the proximal end of the movable arm 5a to the ball 7b, and the terminal 11 as well. And the distance to the contact position. The movable arm 5a tends to displace its tip portion downward due to its own weight, and the one ball 7b tends to be displaced downward due to its own mass and its own weight. Therefore, in the case of the present embodiment, the mass of the one ball 7b itself and the weight of the movable arm 5a constitute a pressing means for pressing the ball 7b toward the outer ring raceway 2. Note that when the force for pressing the balls 7b toward the outer ring raceway 2 is insufficient with these masses and dead weights, an elastic member such as a spring is provided between the measuring device body 8 and the movable arm 5a. The ball 7b may be elastically pressed toward the outer ring raceway 2. In any case, the force that presses the balls 7b toward the outer ring raceway 2 is suppressed to a small value that does not cause the outer ring 1 to be elastically deformed.

  Further, a piezo element 12 as a vibration means is attached to a part of the measuring apparatus main body 8, and a desired voltage is applied to the piezo element 12 by a drive circuit 13 at a desired cycle. . As is well known, the piezo element 12 expands and contracts when a voltage is applied. Therefore, if a voltage that changes at an appropriate frequency such as a high frequency is applied to the piezo element 12 by the drive circuit 13, the piezo element 12. Vibrates at the same frequency as this voltage change, and vibrates the measuring apparatus body 8. In addition, it is preferable to use the piezo element 12 as the above-mentioned vibration means because it is easy to obtain a desired vibration such as a high-frequency vibration with a simple configuration. However, it is possible to obtain a desired vibration based on an electric signal. For example, a device other than a piezo element such as a solenoid can be used.

The operation of measuring the inner diameter of the outer ring raceway 2 at the deepest part where the inner diameter is the largest with the outer ring inner diameter measuring device configured as described above is performed as follows.
First, the outer ring 1 is hooked on the two balls 7a, 7a existing on the upper side in a state where a part of the surfaces of the balls 7a, 7a and the outer ring raceway 2 are in contact with each other. In other words, the outer ring 1 is suspended from the balls 7a and 7a. At this time, the diameter of the circumscribed circle of the three balls 7a and 7b obtained by raising the tip of the movable arm 5a and adding both the balls 7a and 7a and the remaining one ball 7b is set to Keep smaller than the minimum inner diameter. The distal end of the movable arm 5a is lowered after the outer ring 1 is suspended from the balls 7a and 7a, and a part of the surface of the remaining one ball 7b is brought into contact with the outer ring raceway 2 as well. . In this state, the partial surface of the single ball 7b and the outer ring raceway 2 are commensurate with the weight of the movable arm 5a and the elasticity for pressing the terminal 11 of the measuring instrument 6a against the movable arm 5a. Abut with pressure. The partial surfaces of the balls 7a and 7a and the outer ring raceway 2 abut against each other with a pressure commensurate with the force obtained by adding the weight of the outer ring 1 to the pressing force of the one ball 7b.

  Next, the piezo element 12 is driven by the drive circuit 13 to vibrate the measurement apparatus main body 8. This vibration is transmitted from the fixed arm 4a to the two balls 7a, 7a existing on the upper side, and further transmitted to the outer ring 1 suspended by these balls 7a, 7a. As a result, a contact portion between the outer ring raceway 2 and a part of the surface of each of the balls 7a and 7b, each of which is a contact for measuring the inner diameter of the outer ring raceway 2, vibrates. Since these balls 7a and 7b are in light contact with the outer ring raceway 2, the contact portions between the balls 7a and 7b and the outer ring raceway 2 come into contact with the outer ring raceway 2 at the deepest part of the outer ring raceway 2. Move towards.

  That is, if the balls 7a and 7b are pressed toward the outer ring raceway 2 and vibration is applied to the contact portions between the balls 7a and 7b and the outer ring raceway 2, the frictional restraints of these contact portions are released. It is burned. Then, the contact portions between the balls 7 a and 7 b and the outer ring raceway 2 move toward the most mechanically stable position, that is, toward the deepest part of the outer ring raceway 2. In this case, since the force for pressing the balls 7a and 7b toward the outer ring raceway 2 is small, the outer ring 1 is not elastically deformed. Even if the force is small, the balls 7a, The position 7b is stable in a state where it reaches the deepest part of the outer ring raceway 2. Therefore, after driving the piezo element 12 for a time obtained by adding the margin time (added safety factor) to the time required to stabilize, which was obtained experimentally, after stopping the piezo element 12, Based on the positions of the balls 7a and 7b, the diameter (inner diameter) of the bottom of the outer ring raceway 2 is calculated. In this state, the balls 7a and 7b are moved to the deepest part of the outer ring raceway 2, and the positions of the balls 7a and 7b are not slightly displaced by vibration. The inner diameter of the deepest part can be obtained accurately.

In order to calculate the inner diameter R of the bottom of the outer ring raceway 2 based on the positions of the balls 7a and 7b, the diameter of the circumscribed circle of the balls 7a and 7b may be obtained by a mathematical method. In the case of this embodiment, the line segment connecting the centers of the two balls 7a, 7a existing on the upper side is arranged in the horizontal direction, and the remaining one ball 7b is on the vertical bisector of this line segment. Displace at. Therefore, the inner diameter R is obtained as the sum (D + d) of the diameter D of the circumscribed circle of the isosceles triangle connecting the centers of the three balls 7a and 7b and the outer diameter d of each ball. The diameter D of the circumscribed circle of the isosceles triangle is obtained from the length L of the base of the isosceles triangle (the length of the line segment) L and the height H by D = H + L ² / 4H. Among these, the length L of the base is known, and the height H is obtained from the measured value of the measuring device 6a. Therefore, the diameter R of the bottom of the outer ring raceway 2 is obtained by R = H + L ² / 4H + d. Note that the length L of the line segment and the outer diameter d of each of the balls 7a and 7b, which are known values other than the height H in the right side of this expression, are strictly (the inner diameter R of the outer ring raceway 2). With a precision of 10 times or more of the required measurement accuracy).

  The number and arrangement of the piezoelectric elements 12 for applying vibration to the contact portions between the balls 7a, 7b and the outer ring raceway 2, and the waveform and period of the drive signal applied to the piezoelectric elements 12 are as follows. It is determined experimentally or design from the surface that effectively vibrates each contact portion. In this case, it is possible to match the vibration frequency of the piezo element 12 with the resonance frequency of the measuring device including the measuring device main body 8 or the resonance frequency of the outer ring 1 as the object to be measured. This is preferable from the viewpoint of reliably releasing the restraint caused by the friction of the contact portion between the outer ring raceway 2 and the outer ring raceway 2 and moving each contact portion toward the deepest portion of the outer ring raceway 2.

  For this purpose, in order to obtain the resonance frequency, for example, a digitally changing square wave (impulse waveform) drive signal as shown in FIG. 3 or an analog signal as shown in FIG. It is conceivable to change (sweep) the frequency of the sinusoidal drive signal that changes into an equation. If the frequency of the drive signal is changed, the measuring device or the outer ring 1 resonates in the process of the change, so that the frequency of the drive signal is fixed at that time, and each contact portion is the deepest part of the outer ring track 2. Move to. If the frequency variation of the drive signal is performed slowly, it is not always necessary to fix the frequency of the drive signal when the measuring device or the outer ring 1 resonates. In this case, in the process of passing through the resonance frequency, each of the contact portions has completely moved to the deepest portion of the outer ring raceway 2. After the contact portions move to the deepest portion, the contact portions do not move from the deepest portion even if the frequency of the drive signal deviates from the resonance frequency.

  However, when the amplitude of the excitation by the piezo element 12 is increased in order to move the contact parts to the deepest part of the outer ring raceway 2 in a short time, attention should be paid when stopping the vibration of the piezo element 12. is required. That is, in the case where the driving signal is suddenly stopped while the amplitude is increased and the contact portions are vibrated greatly, depending on the vibration direction at the moment of stopping, There is a possibility that each contact portion moves. Depending on the direction and magnitude of this displacement movement (when any contact portion is displaced so as not to be ignored from the deepest part of the outer ring raceway 2), the measured inner diameter of the outer ring raceway 2 cannot be ignored. Some errors may occur. In order to eliminate the possibility of a measurement error due to such a cause, it is preferable to reduce the drive signal sent to the piezo element 12 in a stepwise manner as shown in FIG. Although FIG. 5 shows a square-wave drive signal, the same applies to a sine-wave drive signal.

  In addition, although the above-mentioned description is a case where the resonant frequency of the said measuring apparatus or the said outer ring 1 is unknown, the resonant frequency of these measuring apparatuses or the outer ring 1 is often known beforehand. In this case, the drive signal is matched with this resonance frequency from the beginning (the frequency of the drive signal is fixed). On the other hand, when the inner diameter of the outer ring raceway 2 is measured with respect to the outer ring 1 having a different specification from that of the former, the measurement device or the condition where the outer ring 1 is caused to resonate is unknown. In order to set the amplitude or vibration frequency of the sensor to a value that can resonate the measuring device or the outer ring 1, the intensity or frequency of the drive signal sent to the piezo element 12 is set as shown in FIG. 6 or FIG. Changing it is also effective. Of these, the drive signal shown in FIG. 6 has a constant sweeping time {the time from when the voltage drops until it rises again (the time when the voltage is 0)}, and the voltage is changed to keep the piezoelectric element 12 constant. The amplitude of the vibration is changed while vibrating at the frequency. Further, the drive signal shown in FIG. 7 is obtained by changing the sweep time or the duty ratio (ratio of voltage rise time and non-rise time in one cycle). Which drive signal is used or which drive signal is used in combination is appropriately selected according to the size and shape of the outer ring 1 as the object to be measured. When the drive signal is a sine wave signal, the same can be basically considered.

  8 to 9 show Example 2 of the present invention. This embodiment shows a case where the present invention is applied to measure the outer diameter of the inner ring 14 constituting the single row deep groove type ball bearing at the deepest part of the deep groove type inner ring raceway 15. The inner ring raceway 15 is formed at the axially central portion of the outer peripheral surface of the inner ring 14. Further, the center of curvature of the inner ring raceway 15 exists in the central portion of the inner ring 14 in the axial direction. Therefore, the deepest part of the inner ring raceway 15 exists in the center part of the inner ring 14 in the axial direction, and the inner ring 14 has an axially symmetrical shape with respect to the deepest part.

  The outer diameter measuring device according to the present embodiment, which measures the outer diameter of the inner ring raceway 15 formed on the outer peripheral surface of the inner ring 14 at the deepest portion thereof, includes three balls 7c and 7d, each of which is a contact. . Of these three balls 7c and 7d, the two balls 7c and 7c existing on the lower side are installed at the same height position. In other words, the line segment connecting the centers of these balls 7c, 7c is arranged in the horizontal direction. For this reason, in the case of the present embodiment, the fixed arm 4b protrudes from the lower part of the front surface (left surface in FIG. 8) of the measuring apparatus main body 8a, and the support concave portions 9b and 9b provided on both sides of the upper surface of the fixed arm 4b In addition, the balls 7c and 7c are supported and fixed by adhesion or the like.

  On the other hand, the remaining one ball 7d is movable in the vertical direction above the balls 7c and 7c so as to be movable on a vertical bisector relating to a line connecting the centers of the balls 7c and 7c. It is provided in a state where it can be displaced. For this reason, in the case of the present embodiment, the movable arm 5b is arranged inside the mounting hole 10a provided in the upper part of the measuring apparatus main body 8a. The movable arm 5b supports the base end of the movable arm 5b so that it can swing around a horizontal axis (not shown). The single ball 7d is supported and fixed by bonding or the like to the supporting recess 9c provided on the lower surface of the distal end of the movable arm 5b.

Further, the vertical displacement of the single ball 7d is measured by the measuring device 6b. Therefore, in the case of the present embodiment, the terminal 11a of the measuring device 6b is brought into contact with the upper surface of the intermediate portion of the movable arm 5b.
Further, a piezo element 12 as a vibration means is attached to a base end portion of the fixed arm 4b in a part of the measuring apparatus main body 8a, and a desired frequency is provided to the piezo element 12 by a drive circuit 13. The voltage is applied.

The operation of measuring the outer diameter of the inner ring raceway 15 at the deepest part where the outer diameter is the smallest with the inner ring outer diameter measuring device configured as described above is performed as follows.
First, the inner ring 14 is placed on the two balls 7c, 7c existing on the lower side in a state where a part of the surfaces of the balls 7c, 7c and the inner ring raceway 15 are in contact with each other. At this time, the tip of the movable arm 5b is raised, and the diameter of the inscribed circle of the three balls 7c, 7d obtained by adding both the balls 7c, 7c and the remaining one ball 7d is set to the inner ring 14 It should be larger than the maximum outer diameter. The tip of the movable arm 5b is lowered after the inner ring 14 is placed on the balls 7c, 7c so that the partial surface of the remaining one ball 7d also contacts the inner ring track 15. .

  Next, the driving circuit 13 drives the piezo element 12 to vibrate the measuring device main body 8 at high frequency, so that the contact portions between the balls 7 c and 7 d and the inner ring raceway 15 are the deepest of the inner ring raceway 15. Move towards the department. Based on the positions of the balls 7c and 7d, the diameter (outer diameter) of the bottom of the inner ring raceway 15 is calculated. In the case of the present embodiment, the center of the two balls 7c, 7c existing on the lower side is arranged in the horizontal direction, and the remaining one ball 7d is on the vertical bisector of this line segment. Displace at. Therefore, the diameter is obtained as a difference (D−d) between the diameter D of the circumscribed circle of the isosceles triangle connecting the centers of the three balls 7c and 7d and the outer diameter d of each ball. Other configurations and operations are the same as those of the first embodiment described above, and thus redundant description is omitted.

In the present invention, the diameter measuring method for a member having a circular peripheral surface described in claim 1 measures the diameter of the concave groove formed on the peripheral surface of the member having a circular peripheral surface at the deepest portion. However, the dimensions that change in response to the change in diameter can be measured. For example, the invention described in Patent Document 3 described above can be applied to a radial ball bearing, and the internal clearance of the radial ball bearing can be measured to accurately measure the internal clearance. In this case, the radial ball bearing is fixed with one of the inner ring and the outer ring constituting the radial ball bearing in a state where the central axis thereof is disposed in the horizontal direction, and the other is lifted and lowered. Measure the amount (radial displacement). If the radial ball bearing is vibrated at a high frequency prior to measurement, the rolling surfaces of a plurality of balls constituting the radial ball bearing come into contact with the deepest part of the outer ring raceway and the inner ring raceway, and the internal gap Is required accurately.
Further, the diameter measuring method of the member having a circular peripheral surface described in claim 1 is not limited to the inner diameter of the outer ring and the outer diameter of the inner ring constituting the ball bearing, but the peripheral surface such as a ball screw or a linear guide. The present invention can also be applied to the case where the radial dimension of a member having a groove having an arc cross section is measured at the deepest portion of the groove.

1 is a partially longitudinal side view showing Embodiment 1 of the present invention. The figure seen from the left side of FIG. The diagram which shows the 1st example of the drive signal sent into a piezo element. The diagram which shows the 2nd example. The diagram which shows the 3rd example. The diagram which shows the 4th example. The diagram which shows the 5th example. The partial longitudinal section side view showing Example 2 of the present invention. The figure seen from the left of FIG. The vertical side view which shows an example of the conventional structure. FIG. 11 is a cross-sectional view taken along the line AA in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Outer ring raceway 3a, 3b, 3c Ball 4, 4a, 4b Fixed arm 5, 5a, 5b Movable arm 6, 6a, 6b Measuring instrument 7a, 7b, 7c, 7d Ball 8, 8a Measuring device main body 9, 9a, 9b, 9c Support recess 10, 10a Mounting hole 11, 11a Terminal 12 Piezo element 13 Drive circuit 14 Inner ring 15 Inner ring track

Claims (6)

  A method of measuring a diameter of a member having a circular peripheral surface, in which a concave groove having a circular arc cross section is formed on any peripheral surface at the deepest portion of the concave groove. In a state where a plurality of contacts existing in a single vertical plane are pressed against the bottom surface of the concave groove, high-frequency vibration is applied to the contact portion between each contact and the member having the circular peripheral surface. By moving the contact portion between each of the contacts and the member having the circular peripheral surface to the deepest portion of the concave groove, and then measuring the dimension related to the diameter, the circular peripheral surface is provided. Method for measuring the diameter of a member. An apparatus for measuring a dimension related to the diameter of a member having a circular peripheral surface formed with a concave groove having a circular arc cross section over the entire circumference on any peripheral surface at the deepest portion of the concave groove, A plurality of contacts, pressing means, measuring means, computing means, and vibration means,
A plurality of contacts among them exist in a single vertical plane, and at least one of the contacts can be displaced in the diameter direction of the member having the circular peripheral surface. Supported,
The pressing means presses the contact supported so as to be displaceable in the diameter direction of the member having the circular peripheral surface toward the bottom surface of the concave groove,
The measuring means measures a displacement amount in the diameter direction of a contact supported so as to be displaceable in the diameter direction of the member having the circular peripheral surface,
The calculation means obtains the diameter of the member having the circular peripheral surface at the deepest part based on the displacement amount measured by the measurement means,
The vibrating means applies vibration to at least one of the member having the circular peripheral surface and each contactor. Diameter measuring apparatus for a member having a circular peripheral surface.   A member having a circular peripheral surface is an outer ring constituting a radial ball bearing in which a deep groove type outer ring raceway is formed on the inner peripheral surface, and each contactor has a radius of curvature of 2 in the cross-sectional shape of the outer ring raceway. Three balls having a diameter smaller than double, the centers of these three balls are arranged on a single vertical plane, and the upper two balls of these three balls are the same It is fixed at the height position, and the remaining one ball is supported below the two balls so that it can move on the vertical bisector of the line connecting the centers of these two balls. The diameter measuring device for a member having a circular peripheral surface according to claim 2, wherein the measuring means measures the amount of displacement of the one ball on the perpendicular bisector.   A member having a circular peripheral surface is an inner ring constituting a radial ball bearing in which a deep groove type inner ring raceway is formed on the outer peripheral surface, and each contactor is twice the radius of curvature of the cross-sectional shape of the inner ring raceway. Three balls having a smaller diameter, the center of these three balls being arranged on a single vertical plane, and the lower two balls of these three balls being the same It is fixed at the height position, and the remaining one ball is supported above these two balls so that it can move on the vertical bisector of the line connecting the centers of these two balls. The diameter measuring device for a member having a circular peripheral surface according to claim 2, wherein the measuring means measures the amount of displacement of the one ball on the perpendicular bisector.   The member having a circular peripheral surface according to any one of claims 2 to 4, wherein the frequency of the high-frequency vibration generated by the vibration means coincides with a resonance frequency of a member having a circular peripheral surface or a resonance frequency of a measuring device. Diameter measuring device. The diameter measuring apparatus for a member having a circular peripheral surface according to any one of claims 2 to 5, wherein the excitation means is a piezo element.

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