JP2003021572A - Impact test equipment for rolling bearings - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide an impact test apparatus capable of accurately evaluating impact resistance as a rolling bearing unit. The impact test apparatus has a fixed base for mounting an outer ring of a rolling bearing and an impact receiving member for mounting an inner ring. As an impact applying member for applying an impact to the impact receiving member 2, a head 3 disposed above the impact receiving member 2, an arm 4 to which the head 3 is fixed at one end, and a longitudinal direction of the arm 4 It has a support member 5 that supports the center.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact test device for a rolling bearing. [0002] Conventionally, the evaluation of the impact resistance of a rolling bearing has been carried out.
It is performed not in the bearing alone but in the product. For example, a spindle motor M for a hard disk drive as shown in FIG.
1 and J2 are incorporated, but the spindle motor M is attached to a commercially available impact resistance tester to perform an impact test. The sound of the spindle motor is measured before and after the impact is applied, the acoustic value increased by the application of the impact is measured, and the impact resistance of the rolling bearing is evaluated based on the increased acoustic value. However, in this method, the results obtained vary depending on the state of the bearing being incorporated into the product or the state of fixing the product to the testing machine. However, there is a problem that it is difficult to accurately evaluate the impact resistance. The present invention has been made in view of such problems of the conventional technology, and has as its object to provide an impact test apparatus capable of accurately evaluating the impact resistance of a rolling bearing alone. [0004] In order to solve the above-mentioned problems, the present invention is directed to a fixing stand for mounting one of the bearing rings of a rolling bearing, and the other bearing ring (the bearing ring to which an impact is directly applied). ), An impact applying member for applying an impact to the impact receiving member, an impact force setting means for setting the magnitude of the impact applied by the impact applying member, and detecting an impact force generated on the fixed base. An impact test device for a rolling bearing, comprising: According to this device, one of the inner and outer rings is fixed and an impact is applied to the other, thereby directly applying an impact to the rolling bearing alone and directly detecting the impact force applied to the rolling bearing alone. The impact resistance of the bearing alone can be accurately evaluated. Hereinafter, embodiments of the present invention will be described. FIG. 1 is a schematic configuration diagram showing one embodiment of the impact test apparatus of the present invention. FIG. 2 is an enlarged view of the portion A in FIG. As shown in these figures, this device
The rolling bearing J includes a fixed base 1 on which an outer ring (one race) G of the rolling bearing J is mounted, and an impact receiving member 2 on which an inner race (other race) N is mounted. As an impact applying member for applying an impact to the impact receiving member 2, a head 3 disposed above the impact receiving member 2, an arm 4 to which the head 3 is fixed at one end, and a longitudinal direction of the arm 4 A support member 5 that supports the center is provided. At the end of the arm 4 opposite to the head 3, a balance weight (impact force setting means) 6 is attached slidably in the length direction of the arm 4. The magnitude (impact force) G of the impact applied to the impact receiving member 2 by the head 3 is set by the position of the weight 6 in the length direction of the arm 4. The fixed base 1 is a block body having a columnar concave portion 11 in the center,
A peripheral groove into which the outer ring G is fitted is formed. Further, a sensor (impact force detecting means) 17 for detecting an impact force g1 generated on the fixed base 1 is attached to a portion of the fixed base 1 below the concave portion 11. The impact receiving member 2 has a shape having a circumferential groove for fitting the inner ring N at a lower portion of the shaft body, and has an upper surface serving as an impact receiving surface. A response monitor 71 for detecting acceleration, speed, and displacement generated in the shock receiving member 2 is attached to a lower surface of the shock receiving member 2. A sensor (impact force detecting means) 7 for detecting an impact force g2 generated in the impact receiving member 2 is mounted above the circumferential groove of the impact receiving member 2 in which the inner ring N is fitted. These sensors 7 and 17 are connected to an amplifier 8 for amplifying a signal from each sensor. The response monitor 71 is connected to another amplifier 81. Both amplifiers 8 and 81 are connected to the analyzer 9. Then, the analysis device 9 displays a time-series change of the impact as shown in FIG. 3 based on the impact force detection result by the sensors 7 and 17 and the detection result of the acceleration and the like by the response monitor 71. . The analyzing device 9 is configured to detect the impact force detection value g2 by the sensor 7 of the impact receiving member 2 and the sensor 17 of the fixed base 1.
Is calculated, the difference from the impact force detection value g1 is calculated, and if the difference is within a predetermined value, "the impact force applied to the impact receiving member 2 does not attenuate in the middle or change due to friction or the like. And transmitted to the fixed base (ie, a correct test result was obtained). ", And an analysis was performed using the impact force detection value g1 obtained by the sensor 17 of the fixed base 1, and the difference was larger than a predetermined value. If it does, it is configured to judge that a correct test result was not obtained, and display that fact. The head 3 is composed of a vertically divided cylindrical body 3
1, 32, a disk-shaped elastic body 33 sandwiched between the two cylindrical bodies 31, 32, an adjusting screw 34 for integrating these members to adjust the tightening force of the elastic body 33, and a lower cylindrical body A contact portion 35 fixed to the bottom surface of the body 32 and brought into contact with the impact receiving member 2. The contact surface of the contact portion 35 is formed as a spherical surface. The time T during which the impact is applied to the impact receiving member 2 is determined by the radius of curvature of the spherical surface and the tightening force of the elastic body 33 by the adjusting screw 34. Impact time T
Is shorter as the tightening force of the adjusting screw 34 is larger,
The shorter the radius of curvature of the spherical surface forming the contact portion 35, the shorter the radius. This device is used as follows. First, the radius of curvature of the spherical surface forming the contact portion 35 and the tightening force of the adjusting screw 34 are adjusted in accordance with the set impact application time T, and the length of the arm 4 of the weight 6 is adjusted in accordance with the applied impact force G. Adjust position in direction. Further, the outer ring G is attached to the fixed base 1, and the inner ring N is attached to the impact receiving member 2, respectively. Next, by rotating the arm 4 about the shaft 51 and raising the head 3 side of the arm 4,
After raising the head 3 to a predetermined height, the head 3 of the arm 4
Lower the side. Thereby, the contact portion 35 of the head 3
Contact the impact receiving member 2 with the set impact force, and as a result, an impact is directly applied to the inner ring N. Accompanying this, after the detection of the impact force by the sensors 7 and 17 and the detection of the acceleration and the like by the response monitor 71, the time series change of the impact as shown in FIG. Therefore, by applying an impact to the rolling bearing J by using this device, rotating the rolling bearing J before and after that, measuring the sound, and calculating the difference (sound rise value) between the two, the rolling bearing J is obtained. The impact resistance as a single unit can be accurately evaluated. In the apparatus shown in FIG. 1, since a test for directly applying an impact to the inner ring N is performed, the fixing table 1 and the impact receiving member 2 shown in FIG.
, An inner ring N is attached to the impact receiving member 2, respectively. When a test for directly applying an impact to the outer ring G is performed, the fixing base 10 and the impact receiving member 20 shown in FIG. 4 are used. The fixed base 10 has a shape in which a shaft 12 protrudes upward, and the shaft 12 has a circumferential groove into which the inner ring N is fitted. A sensor (impact force detecting means) 17 for detecting an impact force g1 generated on the fixed base 10 is attached to a portion of the fixed base 10 below the shaft portion 12. The impact receiving member 20 has a concave portion 21 on the fixed base 10 side (lower side),
It has a convex part 22 on the upper surface, and is arranged so as to cover the upper surface and the upper peripheral surface of the shaft part 12 of the fixed base 10. Impact receiving member 2
The upper surface of the 0 convex portion 22 is a surface with which the contact portion 35 of the head 3 contacts. A response monitor 71 for detecting acceleration, velocity, and displacement generated in the impact receiving member 20 is attached to a position directly below the convex portion 22 of the concave portion 21.
Above the response monitor 71 of the impact receiving member 20, a sensor (impact force detecting means) 7 for detecting an impact force g2 generated in the impact receiving member 20 is attached. Using the apparatus shown in FIG. 1, the inner diameter is 4 mm and the outer diameter is 10 mm.
The impact resistance of a ball bearing having a width of 2.5 mm and a width of 2.5 mm was evaluated. This ball bearing corresponds to the ball bearings J1 and J2 incorporated in the spindle motor M for a hard disk drive shown in FIG. That is, an impact force was applied to the ball bearings of various sizes using the apparatus of FIG. The radius of curvature of the spherical surface forming the contact portion 35, the shape of the impact receiving member 2, the material of the contact portion 35 and the impact receiving member 2, the tightening force of the adjusting screw 34, and the like were adjusted to change the applied impact force. The sound was measured by rotating the ball bearing before and after the impact was applied, and the sound rise value increased by the application of the impact was measured. The results are summarized in a graph in which the vertical axis represents the sound rise value and the horizontal axis represents the magnitude of the impact. The graph is shown in FIG. As a comparative example, two same ball bearings were mounted on a spindle motor M shown in FIG.
In the state assembled as No. 2, it was attached to a commercially available impact resistance tester shown in FIG. 7 to evaluate impact resistance. That is, an impact force was applied to the spindle motor M in various sizes, the spindle motor M was rotated before and after the impact was applied, the sound was measured, and the sound rise value increased by the application of the impact was measured. The results are summarized in a graph in which the vertical axis represents the sound rise value and the horizontal axis represents the magnitude of the impact given. The graph is shown in FIG. The testing machine of FIG.
A guide plate 42, which is guided by a guide shaft 41 and is vertically movable, a contact portion 43 fixed to the lower surface of the guide plate 42, and an impact receiving member 44 which receives an impact due to the lowering of the contact portion 43. Have. With the product mounted on the guide plate 42, the guide plate 42 is lowered and the contact portion 43
Is made to collide with the impact receiving member 44 to apply an impact to the product. Here, the spindle motor M is mounted on the guide plate 42 by mounting and fixing the base D of the housing of the ball bearings J1 and J2 shown in FIG. Therefore, as shown by “B” in FIG. 5, an upward impact force is applied to the spindle motor M. Accordingly, the impact force applied to the ball bearings J1 and J2 is due to the inertial force of members on the shaft S indicated by reference numerals 53, 54 and 55. This inertial force is determined by the ball bearings J1, J2
Of the spindle motor M or the fixed state of the spindle motor M to the test machine. Comparing the graph of FIG. 6 with the graph of FIG. 8, the graph of FIG. 6 shows a small variation in the data and shows a certain relationship between the sound rise value and the magnitude of the applied impact. It can be seen from the graph of FIG. 8 that the variation in data is large. This variation is caused by the ball bearings J1, J
2 depends on the state of assembly into the spindle motor M and the state of fixing the spindle motor M to the testing machine.
It is considered that this occurs due to a change in the impact force applied to J1 and J2. As described above, according to the impact test apparatus of the present invention, it is possible to accurately evaluate the impact resistance of a single rolling bearing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram showing one embodiment of an impact resistance evaluation device of the present invention. FIG. 2 is an enlarged view of a portion A in FIG. FIG. 3 is a graph showing a time-series change of an impact. FIG. 4 is a view showing a fixing base and an impact receiving member used when performing a test for directly applying an impact to an outer ring. FIG. 5 is a sectional view showing an example of a spindle motor. 6 is a diagram plotting the results of an impact resistance test of a rolling bearing performed using the apparatus of FIG. 1 on a graph in which the vertical axis represents the sound rise value and the horizontal axis represents the magnitude of the impact. FIG. 7 is a schematic configuration diagram showing a conventional impact resistance tester. 8 is a diagram plotting the results of an impact resistance test of a spindle motor performed using the apparatus of FIG. 7 on a graph in which the vertical axis represents the sound rise value and the horizontal axis represents the magnitude of the impact. [Description of Signs] 1 Fixed base 2 Impact receiving member 3 Head (impact applying member) 4 Arm 5 Support member 6 Weight (impact force setting means) 7 Sensor (impact force detecting means) 8 Amplifier 9 Analysis device 10 Fixed base 11 Recess 12 Shaft portion 20 Shock receiving member 21 Depression 22 Convex portion 31 Upper cylinder 32 Lower cylinder 33 Elastic body 34 Adjusting screw 35 Contact part 41 Guide shaft 42 Guide plate 43 Contact part 44 Shock receiving member 51 Rotation shaft 53 to 55 Shaft side Member 71 Response monitor 81 Amplifier D Base G Outer ring (one raceway) J1, J2 Ball bearing J Rolling bearing N Inner race (other raceway) M Spindle motor S Shaft

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Shinichiro Asae             Kanagawa Prefecture Fujisawa City Kugenuma Shinmei 1-chome 5-50             Nippon Seiko Co., Ltd. (72) Inventor Yoshihiro Sato             Kanagawa Prefecture Fujisawa City Kugenuma Shinmei 1-chome 5-50             Nippon Seiko Co., Ltd. (72) Inventor Hironari Sakota             Kanagawa Prefecture Fujisawa City Kugenuma Shinmei 1-chome 5-50             Nippon Seiko Co., Ltd. F-term (reference) 2G024 AC01 BA12 CA13 DA12 EA06                       FA03                 2G061 AA13 AB04 CB13 DA01 DA16                       EA02 EA03 EA08 EA09

Claims (1)

Claims: 1. A fixed base for mounting one race of a rolling bearing, an impact receiving member for mounting the other race, and
An impact applying member for applying an impact to the impact receiving member, impact force setting means for setting the magnitude of the impact applied by the impact applying member, and impact force detecting means for detecting an impact force generated on the fixed base are provided. An impact test device for rolling bearings.