JP4899307B2 - Bearing preload measurement method - Google Patents

Description

The present invention relates to a preload measuring method of a bearing that is performed in the step of producing a combined bearing.

  As an example of a conventional bearing preload measurement method, when producing a combined bearing, in order to obtain a preload generally suited to the application, the difference width of several bearing units is measured, and the combination of the measured values of the difference width There is known a preload measurement method in which the preload obtained from the above is theoretically calculated to determine the combination of bearings.

  In the above preload measurement method, when the preload is not satisfied and a combined bearing is not possible, the end faces of the inner and outer rings of these bearings are processed by grinding and lapping, and the preload is obtained by adjusting the differential width of the bearings. It was.

  As another example of a conventional bearing preload measurement method, the first load and the second load are set by the load setting means, and the first load and the second load set by the pressurizing means are applied to at least one of the inner ring and the outer ring. In addition, the negative clearance is increased / decreased, the amount of axial displacement of the outer ring is detected in a state where the first load and the second load are applied by the outer ring displacement detecting means, and the first load and the second load are detected by the inner ring displacement detecting means. In the applied state, the axial displacement amount of the inner ring is detected, the difference between the axial displacement amounts of the inner ring and the outer ring detected by the displacement difference calculating means is calculated, and the displacement amount calculated by the rigidity value calculating means is calculated. A preload measurement method for calculating the bearing stiffness value based on the difference is known (see, for example, Patent Document 1).

  In Patent Document 1 described above, the rigidity value is calculated from the change in the relative position of the inner ring and the outer ring, so that a high rigidity is required without including a spring element other than the contact spring between the rolling element and the outer ring. The rigidity value was measured accurately.

  As yet another example of the conventional bearing preload measurement method, the difference width value set in advance while applying a load to the bearing is compared with the difference width value obtained from the measuring device to match the set value. A preload measurement method is known in which the magnitude of the load when they coincide with each other is extracted as an electrical signal by a load detector (see, for example, Patent Document 2).

In Patent Document 2, pressure is applied to the extent that the bearing does not move in the axial direction using an air cylinder, the inner ring is rotated by a jig, the lead screw is rotated via a motor, and the load position changing member is moved. The preload was measured by changing the pressure on the bearing.
Japanese Patent Laid-Open No. 10-096672 (pages 2 to 4, FIG. 1) Japanese Patent Laid-Open No. 55-043405 (pages 1 and 2, FIG. 1)

  However, in the preload measurement method that determines the combination of bearings by theoretically calculating the preload obtained from the combination of the above measured values of the difference width, the measurement of the difference width affects the accuracy of the measuring instrument and the end face accuracy of the inner ring and outer ring. When the receiver and the bearing are combined, there may be a difference between the preload actually applied and the calculated value. As a result, it is difficult to produce and provide a combined bearing by measuring accurate preload when a small preload is required or when the preload standard is narrow. In addition, a difference in measured values is likely to occur due to the skill level and sense of the operator, and a bearing with high rotational accuracy and stable torque cannot be obtained when an accurate preload cannot be set.

  Further, in the above-mentioned Patent Document 1, in addition to having the same problem as described above, since the structure is complicated, the preload cannot be set with a simple structure.

  Moreover, in the said patent document 2, since an air cylinder is easy to receive to the influence of a frictional force, an exact preload cannot be measured.

The present invention has been made in view of the above-described circumstances, and its purpose is to produce and provide a combination bearing by measuring an accurate preload with a simple structure without being affected by the skill level and sense of the operator. Another object of the present invention is to provide a bearing preload measuring method that can be used.

1) A bearing preload measuring method according to the present invention includes a supporting means for supporting a combined bearing formed by superimposing first and second bearings in the axial direction, and the combined bearing supported by the supporting means. A pressurizing means for applying a predetermined load in the axial direction, a load measuring means for measuring a load applied by the pressurizing means, and a differential width of the combination bearing when the load is applied by the pressurizing means. And a displacement measuring means for measuring displacement , wherein the first and second bearings are overlapped in the axial direction so as to be in the state of the combined bearing and the preload of the combined bearing is measured. The first and second bearings have one outer ring, the first and second bearings have one inner ring, and the differential width is the combined bearing. Said first and second axes of state An axial clearance distance between the end faces facing phases, from the state of the distance L1 is L1> 0 of the difference width, will apply a load to the combined bearing in the pressurizing unit, the first and second Since the opposite end surfaces of the bearings contact each other and the distance L1 becomes 0, the first load when the displacement measured by the displacement measuring means is not changed and the distance L1 of the difference width is 0. From this state, the load by the pressurizing means is removed, and the opposite end faces of the first and second bearings are separated from each other, and the distance L1 becomes L1> 0. A second load when the displacement starts to fluctuate, and a load when the displacement disappears and a load when the displacement begins to fluctuate according to the measured displacement value measured by the displacement measuring means. pre of the duplex bearing using the values of the first and second load It is characterized by measuring the.

According to preload measuring method of a bearing according to the above 1), it is possible to accurately measure the preload a simple structure without being influenced by the experience and feeling of the operator.

According to the bearing preload measuring method of the present invention, it is difficult to produce and provide a combined bearing by measuring an accurate preload when a minute preload is required or when a preload standard is narrow. It is possible to solve the problem that the measured value is likely to be affected by the influence and the preload cannot be set with a simple structure, which makes it possible to achieve a simple structure without being affected by the skill level and sense of the operator. It is possible to produce and provide a combined bearing by measuring an accurate preload.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.
FIG. 1 is a front view of a bearing preload measuring apparatus as an embodiment of a bearing preload measuring method and apparatus according to the present invention, FIG. 2 is a side view of the bearing preload measuring apparatus shown in FIG. 1, and FIG. 4 is a sectional view of a preload unit in the bearing preload measuring apparatus shown in FIG. 4, FIG. 4 is a sectional view around the housing in the bearing preload measuring apparatus shown in FIG. 1, and FIGS. 5, 6, and 7 are preload measurements of the bearing shown in FIG. FIG. 8, FIG. 9, FIG. 10 are sectional views around the bearing for explaining the difference width in the bearing preload measuring device shown in FIG. 1, and FIG. 11 is a measurement using the bearing preload measuring device shown in FIG. It is a graph of the load value and displacement amount to perform.

  As shown in FIG. 1 and FIG. 2, a bearing preload measuring device 10 using a bearing preload measuring method according to an embodiment of the present invention includes a base 11, a vertical plate member 12, a horizontal plate member 13, and the like. A motor 14, a linear head 15, a preload unit 16 having a spring mechanism 17, a base plate 18, a housing 19, a load cell 20, a load cell base 21, a displacement detection plate (shown in FIG. 4) 22, A contact-type displacement measuring device (shown in FIG. 4) 23, and a combination bearing (shown in FIG. 4) 50 is disposed on the inner peripheral portion of the housing 19.

  The base 11 is formed in a box shape. A vertical plate member 12 is erected on the base 11, and a base plate 18 is disposed on a reference surface in front of the vertical plate member 12. .

  A horizontal plate member 13 is coupled to an upper end portion of the vertical plate member 12, and a motor 14 is fixed. The motor 14 is coupled to the linear head 15. The linear head 15 converts the rotational force generated by the motor 14 into a linear motion, that is, a vertical motion of the preload unit 16. The combination of the motor 14 and the linear head 15 allows a load to be applied slowly and smoothly in a stepless manner of about several μm / sec, so that the preload can be accurately measured.

  The preload unit 17 includes a rod 24 and a spring mechanism 17. The rod 24 has an upper end connected to the linear head 15 and a lower end screwed to a first plate member 25 provided in the spring mechanism 17. In the spring mechanism 17, a second plate member 27 is assembled to the first plate member 25 via a plurality of pairs of pivot shafts 26, and a plurality of pairs of springs 28 are assembled around the pivot shaft 26. . The spring 28 has an upper end locked to the first plate member 25 and a lower end locked to the second plate member 27.

  The housing 19 is formed in a cylindrical shape and is disposed on the base plate 18. The load cell base 21 is disposed on the combination bearing 50 incorporated in the inner peripheral portion of the housing 19, and the load cell 20 is disposed on the load cell base 21. The displacement detection plate 22 is arranged on the combination bearing 50 and is pressed by the load cell base 21.

  As shown in FIG. 3, the rod 24 is inserted into the first screw member 29 after the screw shaft 29 formed at the lower end is inserted into the screw hole 30 formed at the center of the first plate member 25, and then the nut 31 is screwed. A single plate member 25 is fixed.

  The pivot 26 is inserted into a pivot hole 32 formed in the first plate member 25 so as to be movable in the axial direction, and an upper end portion protruding above the first plate member 25 is larger than the inner diameter of the pivot hole 32. It is supported by screwing a nut 34 through a washer 33 having an outer diameter. The lower end portion of the pivot 26 is fixed to the second plate member 27 by screwing the screw shaft 35 into the screw hole 36 formed in the second plate member 27.

  The spring 28 is a torsion coil spring and has a predetermined elastic repulsion force. The spring 28 is disposed on the outer periphery of the pivot 26, and since the upper end is locked to the first plate member 25 and the lower end is locked to the second plate member 27, the second plate member A top portion 37 provided at the central portion of the lower surface of 27 is disposed opposite to a top portion (shown in FIG. 5) 38 provided at the central portion of the upper surface of the load cell 20. Since the spring 28 has better followability than a pressing means such as an air cylinder, it can measure even a slight preload. Since the spring 28 can easily change the natural length and the spring constant, the range of the load applied to the combination bearing 50 can be easily changed.

  As shown in FIG. 4, the combination bearing 50 includes a pair of angular ball bearings 51 and 52, and the outer rings 53 and 54 of the angular ball bearings 51 and 52 are inserted into the inner peripheral portion of the housing 19. Yes. At this time, since the hole 39 of the base plate 18 is larger than the outer diameter of each of the inner rings 55 and 56 of the angular ball bearings 51 and 52, the outer ring of the other angular ball bearing 52 disposed on the lower side. 54 abuts against the end face. Angular contact ball bearings 51 and 52 have outer ring raceway surfaces (not shown) formed on inner peripheral portions of outer rings 53 and 54 and inner ring raceway surfaces (not shown) formed on outer peripheral surfaces of inner rings 55 and 56. ), And a plurality of balls 57, 57, and retainers 58, 58 for holding the balls 57, 57 rotatably in the circumferential direction. The angular ball bearings 51 and 52 employed here are bearings to which a slight preload is applied.

  The displacement detection plate 22 is movably inserted into the inner peripheral portion of the housing 19, and the end portion of the outer ring 53 of one angular ball bearing 51 in which the cylindrical portion 40 formed at the lower end portion is disposed on the upper side. Abut. A displacement measuring unit 41 is provided at the center of the upper surface of the displacement detection plate 22, and the contact 41 in the contact-type displacement measuring instrument 23 is brought into contact with the displacement measuring unit 41. On the upper surface of the displacement detection plate 22, a column portion 43 provided on the load cell base 21 is brought into contact.

Next, a bearing preload measuring method using the bearing preload measuring apparatus 10 will be described with reference to FIGS.
As shown in FIG. 5, the preload unit 16 is arranged above the load cell 20 in a state before measuring the preload. Then, a pair of angular ball bearings 51 and 52 for measuring are inserted into the housing 19, and the outer ring 54 of the other angular ball bearing 52 disposed below is brought into contact with the base plate 18 and disposed above. The displacement detection plate 22 is brought into contact with the upper end surface of the outer ring 53 of one angular ball bearing 51, the column portion 43 of the load cell base 21 is brought into contact with the upper surface of the displacement detection plate 22, and the load cell 20 is placed on the upper surface of the load cell base 21. Is placed.

  At this time, a T-shaped main shaft member 44 is inserted into the inner rings 55 and 56 of the angular ball bearings 51 and 52. In the main shaft member 44, the upper surface of the head is in contact with the displacement detection plate 22, and the lower surface of the head is in contact with the inner ring 55 of one angular ball bearing 51.

  The load cell base 21 has a base portion 45 on which the load cell 20 is placed on the upper surface, and has a plurality of pillar portions 43 that protrude downward from the base portion 45. The load cell base 21 can uniformly apply the load applied to the load cell 20 to the displacement detection plate 22 via the column portion 43.

  The contact-type displacement measuring device 23 is a contact-type displacement sensor, and measures an amount of displacement that the displacement detection plate 22 has moved through the load cell 20 when a load is applied, and generates an electric signal. The electrical signal generated by the contact-type displacement measuring device 23 is given to the displacement measuring device amplifier 46 and then given to the recording device 47. At this time, the electric signal generated by the load cell 20 is supplied to the load cell amplifier 48 and then to the recording device 47. The electric signal given to the displacement measuring instrument amplifier 46 is amplified and then the displacement amount of the displacement detecting plate 22 is displayed. The electric signal given to the load cell amplifier 48 displays the load value applied to the load cell 20. The recording device 47 measures the preload by recording the load data and the displacement data and performing arithmetic processing.

  As shown in FIG. 6, when the motor 14 is driven and the preload unit 15 is lowered together with the rod 24 by the linear head 15, the top portion 37 of the second plate member 27 contacts the top portion 38 of the load cell 20.

  As shown in FIG. 7, when the top portion 37 of the second plate member 27 starts to press the top portion 38 of the load cell 20 as the preload unit 16 descends gradually, the spring 28 of the spring mechanism 17 is elastically deformed to the contraction side. Therefore, the first plate member 25 is displaced in a direction approaching the second plate member 27, and the load cell 20 is pressed with a load corresponding to the elastic repulsion force accumulated in the spring 28. When a load via the spring 28 is applied to the load cell 20, the electrical signal generated by the contact displacement measuring device 23 is applied to the displacement measuring device amplifier 46 and then to the recording device 47, and the load cell 20 is generated. The electric signal is supplied to the load cell amplifier 48 and then to the recording device 47.

  Next, with reference to FIG. 8, FIG. 9, FIG. 10 and FIG. 11, the fluctuation of the difference width in the preload measuring device 10 will be described.

  As shown in FIG. 8, in the no-load state where the preload unit 16 is arranged above the load cell 20, the difference width between the outer rings 53 and 54 of the angular ball bearings 51 and 52 is a distance L1> 0. It is.

  As shown in FIG. 9, when the load is gradually applied, the difference width at the time of no load gradually decreases, and finally, the upper and lower end surfaces of the outer rings 53 and 54 of the angular ball bearings 51 and 52 are changed. In order to make contact, the difference width between the outer rings 53 and 54 of the angular ball bearings 51 and 52 is a distance L1 = 0.

  As shown in FIG. 10, when the load is gradually removed after the upper and lower end surfaces of the outer rings 53 and 54 come into contact with each other, the upper and lower end surfaces of the outer rings 53 and 54 are separated and the difference width starts to be displaced. The difference width between the outer rings 53 and 54 is the distance L1> 0.

  As shown in FIG. 11, when the load values and displacement amounts in FIGS. 8, 9, and 10 are represented in the graph, the load is gradually applied, and the upper and lower sides of the outer rings 53 and 54 of the angular ball bearings 51 and 52 are respectively An inflection point appears at a position A where the difference width becomes the distance L1 = 0 (see FIG. 9) due to the contact of the end faces. Here, even if a load is further applied, the displacement is not changed because the difference width is 0, and the displacement amount and the load at the position A are recorded in the recording device 47.

  On the other hand, when the load is gradually removed after the upper and lower end surfaces of the outer rings 53 and 54 come into contact with each other, the upper and lower end surfaces of the outer rings 53 and 54 are separated and the difference width starts to be displaced (see FIG. 10). ). Then, an inflection point appears at position B. When the load is set to 0, the difference width at the time of no load is restored. That is, the preload can be measured based on the load appearing at the position A and the load appearing at the position B.

  According to the bearing preload measuring method and the bearing preload measuring apparatus 10 described above, the use of the preload unit 16 with the built-in spring mechanism 17 provides better followability compared to pressurizing means such as an air cylinder. Even when the required preload is very small or the standard is narrow, an accurate preload can be measured. In addition, since it is easy to handle and can be configured with a simple structure, man-hours in management can be reduced. Thereby, it is possible to produce a combined bearing by measuring an accurate preload with a simple structure without being affected by the skill level and feeling of the operator. Further, since the minute preload and the preload of the narrow combination bearing 50 can be measured, the combination bearing 50 can be provided to a field that requires high rotational accuracy and low torque.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. For example, the spring constituting the spring mechanism is not limited to the torsion coil spring shown in the figure, and may be an elastic member that can expand and contract in the axial direction.

  Also, other components excluding the spring mechanism, base, vertical plate member, horizontal plate member, motor, linear head, base plate, housing, load cell, load cell base, displacement detection plate, contact type displacement measuring instrument, Such structures are not limited to those shown in the drawings, but may be changed as appropriate.

  As the combination bearing, a tapered roller bearing may be applied instead of the angular ball bearing shown in the figure.

1 is a front view of a preload measuring device which is an embodiment of a bearing preload measuring method and device according to the present invention. FIG. 2 is a side view of the bearing preload measuring device shown in FIG. 1. It is sectional drawing of the preload unit in the bearing preload measuring apparatus shown in FIG. FIG. 2 is a sectional view around a housing in the bearing preload measuring device shown in FIG. 1. It is operation | movement explanatory drawing of the bearing preload measuring method using the bearing preload measuring apparatus shown in FIG. It is operation | movement explanatory drawing of the bearing preload measuring method using the bearing preload measuring apparatus shown in FIG. It is operation | movement explanatory drawing of the bearing preload measuring method using the bearing preload measuring apparatus shown in FIG. It is sectional drawing of the periphery of a bearing explaining the difference width in the preload measuring apparatus of the bearing shown in FIG. It is sectional drawing of the periphery of a bearing explaining the difference width in the preload measuring apparatus of the bearing shown in FIG. It is sectional drawing of the periphery of a bearing explaining the difference width in the preload measuring apparatus of the bearing shown in FIG. It is a graph of the load value and displacement amount which are measured by the preload measuring apparatus for bearings shown in FIG.

Explanation of symbols

10 Bearing preload measuring device 14 Motor (pressurizing means)
15 Linear head (pressurizing means)
16 Preload unit (pressurizing means)
17 Spring mechanism 18 Base plate (supporting means)
19 Housing (supporting means)
20 load cell (load measuring means)
23 Contact-type displacement measuring instrument (load measuring means)
50 Combination bearings

Claims (1)

Support means for supporting a combined bearing formed by superimposing first and second bearings in the axial direction ;
Pressurizing means for applying a predetermined load in the axial direction to the combination bearing supported by the support means;
Load measuring means for measuring a load applied by the pressurizing means;
Using a displacement measuring means for measuring the displacement of the differential width of the combination bearing when a load is applied by the pressurizing means ,
A bearing preload measurement method for measuring the preload of the combined bearing by superimposing the first and second bearings in an axial direction to form a state of the combined bearing,
Each of the first and second bearings has one outer ring, and each of the first and second bearings has one inner ring,
The difference width is an axial gap distance between the opposing end surfaces of the first and second bearings in the combined bearing state,
From the state where the distance L1 of the difference width is L1> 0, a load is applied to the combination bearing by the pressurizing means, and the opposing end surfaces of the first and second bearings come into contact with each other to contact the distance L1. The first load when the displacement measured by the displacement measuring means is not changed because the value becomes 0;
When the distance L1 of the difference width is 0, the load by the pressurizing means is removed, the opposing end surfaces of the first and second bearings are separated from each other, and the distance L1 becomes L1> 0. Therefore, the second load when the displacement measured by the displacement measuring means starts to fluctuate is obtained,
The preload of the combination bearing is measured by using the first and second load values, which are loads at the time when the displacement has disappeared and when the displacement starts to fluctuate according to the displacement measured by the displacement measuring means. A method for measuring a preload of a bearing.

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