JP2014202639A - Test device for radial rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure capable of sufficiently enhancing the rigidity of a fixed housing 1a and performing a highly reliable test.SOLUTION: The whole of a fixed housing 1a is integrally formed by applying forging processing and cutting processing to a carbon steel-made material. A lubrication oil reservoir 6a is provided inside the housing 1a, and the bottom of the lubrication oil reservoir 6a is made to be a partially cylindrical concave surface that is concentric with the central axis of a revolving shaft 2a.

Description

  The present invention relates to an improvement in a radial rolling bearing test apparatus for evaluating the durability of a radial rolling bearing incorporated in a rotation support portion of an automobile, various machine tools, various industrial machines, and the like.

  The life of a rolling bearing changes due to complicated intertwining of various factors such as the material, shape, size, lubrication state, and load of the bearing rings and rolling elements constituting the rolling bearing. Therefore, in order to obtain a rolling bearing having appropriate durability according to the application, it is necessary to perform a test for knowing the influence of the various factors on the life of the rolling bearing. FIG. 7 shows the radial rolling bearing test apparatus described in Patent Document 1. This radial rolling bearing test device is a housing described in claims, and includes a distal end portion (left end portion in FIG. 7) and a proximal end portion of the rotating shaft 2 on the inner side of the fixed housing 1. It is rotatably supported by a pair of radial rolling bearings 3 and 3 that are test bearings. A movable housing 4 is disposed concentrically with the rotary shaft 2 around an intermediate portion of the rotary shaft 2 located between the radial rolling bearings 3 and 3. The movable housing 4 is provided in the fixed housing 1 in a state in which radial displacement is possible and rotational displacement is prevented. A support bearing 5 is provided between the inner peripheral surface of the movable housing 4 and the outer peripheral surface of the intermediate portion of the rotary shaft 2. The support bearing 5 and the lower half portions of the radial rolling bearings 3 and 3 are immersed in the lubricating oil stored in the lubricating oil reservoir 6 provided inside the fixed housing 1. In this lubricating oil, foreign substances 7 and 7 such as metal powder and ceramic powder are mixed as necessary. Further, a radial load F having a desired value directed in the vertical direction (vertical direction in FIG. 7) can be applied to the movable housing 4 by a pressurizing device such as a hydraulic cylinder.

  When performing a life test of the radial rolling bearings 3, 3, the movable housing 4 is pressed by the pressurizing device, so that the both bearings 5, the support bearings 5, and the rotary shaft 2 are used. The radial rolling bearings 3 and 3 are pressed in the vertical direction, and the rotary shaft 2 is driven to rotate. As a result, a life test for evaluating the durability of the radial rolling bearings 3 and 3 can be performed while being rotated at a desired rotational speed while applying a desired radial load F.

  By the way, in the case of the radial rolling bearing test apparatus as described above, it is important to sufficiently increase the rigidity of the fixed housing 1 in order to perform highly reliable evaluation. That is, when the rigidity of the fixed housing 1 is not sufficient, a portion of the fixed housing 1 that supports the radial load F may be deformed (elastically deformed) by the radial load F. Thereby, the radial load F cannot be normally applied to the radial rolling bearings 3 and 3 which are test bearings, and there is a possibility that the variation of the test results becomes large.

Japanese Patent Laid-Open No. 2007-3196

  In view of the circumstances as described above, the present invention has been invented to realize a radial rolling bearing test apparatus capable of sufficiently increasing the rigidity of a housing and suppressing variations in test results.

The radial rolling bearing test apparatus of the present invention is for performing durability evaluation (life test) of the radial rolling bearing, similarly to the conventionally known radial rolling bearing test apparatus.
The radial rolling bearing to be subjected to the life test includes an outer ring, an inner ring, and a plurality of rolling elements.
Of these, the outer ring has an outer ring raceway on the inner peripheral surface.
The inner ring has an inner ring raceway on the outer peripheral surface.
Each rolling element is provided between the outer ring raceway and the inner ring raceway so as to be freely rollable.

The radial rolling bearing test apparatus of the present invention includes a housing, a rotating shaft, a rotation driving unit, and a load applying unit.
Among these, the rotating shaft is rotatably supported inside the housing, and is for externally fitting the inner ring of the radial rolling bearing.
The rotation driving means rotationally drives the rotation shaft.
Further, the load applying means applies a radial load to the radial rolling bearing.

In particular, in the radial rolling bearing test apparatus of the present invention, the housing is not formed by connecting (fixing) a plurality of members, but is formed integrally as a whole.
When the radial rolling bearing test apparatus of the present invention as described above is implemented, the housing is preferably made of carbon steel as in the invention described in claim 2. That is, the housing is manufactured by forging a material made of carbon steel and further performing cutting as necessary.

Preferably, as in the invention described in claim 3, a lubricating oil reservoir for storing lubricating oil for immersing a part of the radial rolling bearing is provided inside the housing. The load applying means applies a radial load in the horizontal direction.
When the invention described in claim 3 is implemented, preferably, as in the invention described in claim 4, the bottom surface of the lubricating oil reservoir is formed in a partially cylindrical shape concentric with the central axis of the rotating shaft. A concave curved surface. In this case, preferably, as in the invention described in claim 5, the radius of curvature of the bottom surface of the lubricating oil reservoir is not less than 0.6 times and not more than 2 times the outer diameter of the radial rolling bearing (preferably 1 Times).
Preferably, as in the invention described in claim 6, foreign substances such as metal powder and ceramic powder are mixed in the lubricating oil.

  According to the radial rolling bearing test apparatus of the present invention configured as described above, since the housing is integrally formed as a whole, the rigidity of the housing can be sufficiently increased and the radial load is a test bearing. Can be normally applied to radial rolling bearings. As a result, variation in test results can be suppressed, and it is possible to perform highly reliable evaluation on the life of the radial rolling bearing.

Sectional drawing of the testing apparatus for radial rolling bearings which shows one example of embodiment of this invention. The schematic diagram equivalent to the XX cross section of FIG. A plan view (A) showing the fixed housing taken out, and an end view (B) showing a state seen from below (A) The figure shown as a comparative example for demonstrating the effect by forming a fixed housing integrally. Sectional drawing for demonstrating the problem of giving a radial load to a perpendicular direction. Sectional drawing for demonstrating the effect by restrict | limiting the rotation direction of a rotating shaft. Sectional drawing of the testing apparatus for radial rolling bearings which shows an example of the conventional structure.

1 to 3 show an example of an embodiment of the present invention. In the case of this example, the distal end portion (left end portion in FIG. 1) and the proximal end portion of the rotating shaft 2a are rotated with respect to the fixed housing 1a by a pair of radial rolling bearings 3a and 3b, each being a test bearing. Supports freely. That is, the inner rings 8 and 8 of these radial rolling bearings 3a and 3b are externally fitted to the distal end portion and the proximal end portion of the rotating shaft 2a. The inner side surfaces of these inner rings 8 and 8 are in contact with stepped portions 9 and 9 provided at the intermediate portion of the rotating shaft 2a through washers 10 and 10, respectively. Further, a pair of axial side walls standing upright in the vertical direction with the outer rings 11, 11 of the radial rolling bearings 3a, 3b being separated from each other in the axial direction of the rotary shaft 2a of the fixed housing 1a. 12 and 12 are supported. For this purpose, substantially cylindrical support sleeves 14a and 14b are attached to the inner sides of the circular holes 13 and 13 provided in the two axial side wall portions 12 and 12, respectively. The outer rings 11 and 11 are fitted into cylindrical support portions 15a and 15b provided on the inner peripheral surfaces of the distal ends of the support sleeves 14a and 14b. The outer surface of the outer ring 11 constituting the radial rolling bearing 3a of one of the radial rolling bearings 3a and 3b (the right side in FIG. 1) is supported by one of the supporting sleeves 14a and 14b. It abuts against a step surface provided at the back end of the portion 15a. Thus, the one radial rolling bearing 3a is strongly held in the axial direction between the outer surface of the washer 10 and the stepped surface of the support portion 15a of the one support sleeve 14a. On the other hand, the outer surface of the outer ring 11 constituting the other radial rolling bearing 3b of the radial rolling bearings 3a and 3b (the left side in FIG. 1) is supported by the other of the supporting sleeves 14a and 14b. It abuts against the distal end surface of the piston portion 16 that is inserted (inserted) into the sleeve 14b so as to be axially displaceable. As a result, the other radial rolling bearing 3 b is strongly held in the axial direction between the outer surface of the washer 10 and the tip surface of the piston portion 16. In this example, the proximal face of the piston portion 16, not shown, by pressing by the pressure device such as a hydraulic cylinder, the two radial rolling bearing 3a, as capable of imparting axial load F _a desired value 3b I have to.

In addition, a substantially cylindrical movable housing 4a is disposed around the intermediate portion of the rotary shaft 2a so as to be concentric with the rotary shaft 2a. A pair of support bearings 5a and 5a are provided between the inner peripheral surface of the movable housing 4a and the intermediate outer peripheral surface of the rotary shaft 2a. The movable housing 4a is provided inside the fixed housing 1a in a state that allows radial displacement and prevents rotational displacement. In the case of this embodiment, the movable housing 4a, and the manner may impart radial load F _r of the desired value in the horizontal direction. That is, one of the pair of width direction side wall portions 17a and 17b in which the ends of the both axial side wall portions 12 and 12 constituting the fixed housing 1a are connected to each other (right side in FIG. 2). The distal end portion of a substantially cylindrical pressing jig 19 is inserted into a through hole 18 provided in a state of penetrating the portion 17a in the horizontal direction, and the base end surface (right end surface in FIG. 2) of the pressing jig 19 A front end surface (left end surface in FIG. 2) of a pressure device such as a hydraulic cylinder installed outside the fixed housing 1a (width direction side wall portion 17a) is pushed through a steel ball 21 and a pressure plate 22. Thus, a radial load applying means is configured. Further, a vibration sensor 23 is provided on the outer surface of the pressing plate 22, and the vibration sensor 23 detects the vibration of the pressing plate 22, whereby the radial rolling bearings are provided via the members 2 a, 5 a, 4 a, and 19. The vibrations 3a and 3b can be detected freely.
Further, the rotary shaft 2a is connected to an output shaft of a drive source such as an electric motor directly or via a pulley and a coupling spanned by an endless belt, and the rotary shaft 2a is driven to rotate at a desired rotational speed. Rotation drive means for this purpose is configured.

  Further, in the case of this example, the fixed housing 1a is formed in a substantially rectangular box shape with an upper opening, as shown in FIG. 3, and is formed by subjecting a carbon steel material to forging and cutting. It is integrally formed. A lubricating oil reservoir 6a is provided inside the fixed housing 1a. The bottom surface of the lubricating oil reservoir 6a is a partially cylindrical concave curved surface concentric with the rotating shaft 2a. The radius of curvature r of the bottom surface of the lubricating oil reservoir 6a is 0.6 times or more and preferably 2 times or less (preferably 1 time or less) of the outer diameter D of the radial rolling bearings 3a and 3b (0.6D ≦ r ≦ 2D). Further, between the bottom surface of the lubricating oil reservoir 6a and the outer peripheral surfaces of the movable housing 4a and the support sleeves 14a and 14b, plate-shaped heaters 24, both upper and lower side surfaces of the heater 24, and the lubricating oil reservoir 6a, and a gap is provided between the movable housing 4a and the outer peripheral surfaces of the support sleeves 14a and 14b. The heater 24 is curved along the bottom surface of the lubricating oil reservoir 6a. That is, the upper and lower side surfaces of the heater 24 are partially cylindrical curved surfaces concentric with the central axis of the rotating shaft 2a. The lubricating oil reservoir 6a stores lubricating oil mixed with foreign substances 7, 7 such as metal powder and ceramic powder at a desired ratio. For this reason, the mixing rate of the foreign substances 7 and 7 in the lubricating oil does not change during the period from the start of the experiment to the end of the experiment. The lubricating oil is agitated with the rotation of the rotary shaft 2a, and hence the radial rolling bearings 3a, 3b and the support bearings 5a, 5a, and the foreign matters 7, 7 are contained in the lubricating oil. Disperse uniformly. A rectifying means for making the flow of the lubricating oil in the lubricating oil reservoir 6a appropriate can be provided in the lubricating oil reservoir 6a.

When performing the durability test (life test) of the radial rolling bearings 3a and 3b, which are the test bearings, using the radial rolling bearing test apparatus of the present example configured as described above, the rotating shaft 2a is used. In consideration of the agitation effect and the lubricity of the load zone, the range from the lower end portion to the upper end portion of the rotating shaft 2a in the state before the rotating shaft 2a is rotationally driven with lubricating oil in the lubricating oil reservoir 6a It is preferable to regulate to. Therefore, in this example, the lubricating oil is stored so that the oil surface (upper surface) is positioned on the central axis of the rotating shaft 2a. Then, in a state before the rotary shaft 2a is rotationally driven, only the lower half portions of the radial rolling bearings 3a and 3b are immersed in the lubricating oil. Thus, during the life test, at least the lower end portion of the outer peripheral surface of the rotating shaft 2a is immersed in the lubricating oil, and the radial rolling bearings 3a and 3b are at least 1/3 from the lower end in the radial direction. It is designed to be immersed in the lubricating oil. The heater 24 holds the lubricating oil at a desired temperature (for example, 100 ° C.). In the case of this example, the oil surface of the lubricating oil is positioned on the central axis of the rotating shaft 2a before the rotating shaft 2a is driven to rotate. 2a and the radial rolling bearings 3a and 3b can be easily held within a predetermined temperature range. Also, pressing the rotary shaft 2a in the axial direction by pressing the proximal end face of the piston portion 16 adds a desired axial load F _a the two radial rolling bearing 3a, the 3b. Further, the by the pressing rod 20 presses the rotary shaft 2a in the horizontal direction that presses the outer peripheral surface of the movable housing 4a, adds the desired radial load F _r wherein both radial rolling bearing 3a, the 3b. In this state, the rotation (revolution) direction of the balls 25, 25 constituting the both radial rolling bearings 3a, 3b of the rotating shaft 2a is such that the radial load of the radial rolling bearings 3a, 3b is the radial load. The load zone (the portion indicated by a thick line in FIG. 2) located in front of the action direction is rotationally driven at a desired rotational speed in a direction (clockwise in FIG. 2) passing from below to above. As a result, the two radial rolling bearing 3a, 3b is rotated at a desired rotational speed while being added the desired radial load F _r and axial load F _a. In this state, the vibration value (amplitude) of the radial rolling bearings 3a and 3b detected by the vibration sensor 23 is 1.5 times or more and less than 3 times (for example, 2 times) the initial vibration value at the start of the test. The point of time when the set threshold value is exceeded is regarded as the life of these radial rolling bearings 3a and 3b, and the test is terminated. If this threshold value is less than 1.5 times the initial vibration value, the test may be terminated by vibration based on damage other than these radial rolling bearings 3a and 3b. Further, when the threshold is 3 times or more, the damage progresses greatly, and there is a possibility that the site where the damage starts can not be specified. When exchanging the radial rolling bearings 3a and 3b, the radial rolling bearings from both sides in the axial direction of the rotary shaft 2a with the support sleeves 14a and 14b displaced outward in the axial direction. Exchange 3a and 3b.

According to a radial rolling bearing testing apparatus such the example above, the stationary housing 1a, since forming a whole together, sufficiently high rigidity against the radial load F _r and the axial load F _a it can. This effect will be described with reference to FIG. 4 showing a structure according to a comparative example in addition to FIG. The fixed housing 1b has a rectangular box shape with an open top, and a flat bottom plate portion 26 is connected to a pair of side plate portions 27, 27 parallel to each other and ends of both side plate portions 27, 27. It is constructed by supporting and fixing the pair of end plate portions by welding, bonding or the like. That is, the fixed housing 1b is manufactured by connecting five plate members. For this reason, when the radial radial load F _r applied to the rotary shaft 2a is increased, the both side plate portions 27, 27 are located in front of the radial load F _{r in} the acting direction, and the radial load F _r. side plate portions 27 for supporting the (left side in FIG. 4) may be deformed (elastically deformed) in a tilting direction towards the direction of action of the radial load F _r. As a result, the radial load F _r, wherein both radial rolling bearing 3a is a test bearing, it becomes impossible to impart normally 3b, there is a possibility that variations in the test results increases. On the other hand, in the case of this example, the fixed housing 1a is integrally formed as a whole, and the bottom surface of the lubricating oil reservoir 6b is formed as a concave curved surface so that the plate thickness of the both side walls 17a and 17b in the width direction is larger than the upper end. because it has larger at the lower end side it can be sufficiently high rigidity against the radial load F _r. Therefore, the radial load F _r the two radial rolling bearing 3a, and applied successfully 3b, it is possible to prevent the test result varies. Further, since there is no seam formed by combining a plurality of plates on the inner surface of the lubricating oil reservoir 6a, the heat transfer property of the fixed housing 1a can be improved. Further, when the inside of the lubricating oil reservoir 6a is washed, the foreign substances 7 and 7 mixed in the lubricating oil do not adhere (hang) to the seam and remain. Thereby, since the property of this lubricating oil can be easily maintained, variation in test results can be suppressed.

  In the case of this example, since the bottom surface of the lubricating oil reservoir 6a is a partially cylindrical concave curved surface concentric with the central axis of the rotating shaft 2a, the lubricating oil and various sizes mixed in the lubricating oil can be used. The foreign substances 7 and 7 are prevented from staying (depositing) in the lubricating oil reservoir 6a, and the properties of the lubricating oil can be made uniform in the lubricating oil reservoir 6a. That is, in the case of the structure according to the comparative example shown in FIG. 4 described above, the upper surface of the bottom plate portion 26 and the inner surfaces of the side plate portions 27 and 27 in the lubricating oil reservoir 6b provided inside the fixed housing 1b are continuous. The lubricating oil and the foreign substances 7 and 7 mixed in this lubricating oil are likely to stay in the corners (portions surrounded by the chain line α in FIG. 4). On the other hand, in the case of the present example, the bottom surface of the lubricating oil reservoir 6a is formed as a partially cylindrical concave curved surface, thereby preventing the lubricating oil and foreign substances 7 and 7 from staying. Further, in this example, the heater 24 is disposed between the bottom surface of the lubricating oil reservoir 6a and the outer peripheral surfaces of the movable housing 4a and the support sleeves 14a and 14b. Each is provided with a gap between each surface. For this reason, the flow rate of the lubricating oil can be increased at the upper and lower side portions of the heater 24 based on the restriction of the flow path, and the lubricating oil and the foreign matters 7 and 7 can be more difficult to stay. In addition, heat exchange with the lubricating oil can be performed efficiently. In particular, in the case of this example, the radius of curvature r of the bottom surface of the lubricating oil reservoir 6a is set to be not less than 0.6 times and not more than 2 times the outer diameter D of the radial rolling bearings 3a, 3b (0.6D ≦ r ≦ 2D) Therefore, the circulation performance of the lubricating oil can be improved without increasing the required amount of lubricating oil. Furthermore, if the curvature radius r is set to be equal to or less than one time (r ≦ D) of the outer diameter D, the amount of the lubricating oil can be further reduced. That is, when the curvature radius r is larger than twice the outer diameter D (r> 2D), the required amount of lubricating oil increases. On the other hand, when the radius of curvature r is less than 0.6 times the outer diameter D (r <0.6D), the clearance between the upper and lower sides of the heater 24 becomes too narrow, and the circulation property of the lubricating oil is reduced. Decreases. Further, by providing gaps in the upper and lower side portions of the heater 24, the contact area between the upper and lower side surfaces of the heater 24 and the lubricating oil can be increased, and the oil temperature of the lubricating oil can be adjusted efficiently. In addition, since the bottom surface of the lubricating oil reservoir 6a is a concave curved surface and the surface of the lubricating oil reservoir 6a is smoothly continuous, the surface of the lubricating oil reservoir 6a can uniformly absorb or dissipate heat. It is possible to prevent the oil temperature from varying. Specifically, the oil temperature of the lubricating oil stored in the lubricating oil reservoir 6a can be adjusted within a desired temperature range of ± 3 ° C.

And in this embodiment, the two radial rolling bearing 3a, only the lower half of 3b were immersed in the lubricating oil, these two radial rolling bearing 3a, is imparted a radial load F _r in the horizontal direction with respect 3b . Further, the rotational direction of the rotary shaft 2a is restricted so that the balls 25, 25 constituting the radial rolling bearings 3a, 3b rotate (revolve) in a direction passing through the load zone from the bottom to the top. ing. Therefore, the lubrication state of the load area located acts forward of the radial load F _r can be in a proper state, so it tends to be insufficient or exhausted lubricating oil in this loaded zone, variations in test results It is possible to prevent the test time from increasing excessively as a result of an increase in the size or the excessive lubrication. Further, since the revolving direction of the balls 25 and 25 is regulated, the foreign matters 7 and 7 mixed in the lubricating oil stored in the lubricating oil reservoir 6a can be appropriately fed into the load zone. From this aspect, the test result can be stabilized (variation can be suppressed).

  This reason will be described in more detail with reference to FIGS. 5 to 6 in addition to FIG. FIG. 5 shows a structure in which a radial load F is applied in the vertical direction to the radial rolling bearing 3c, which is a test bearing, as in the case of the conventional structure described above. First, when the inner ring 8a of the radial rolling bearing 3c is pressed downward in the vertical direction via the rotating shaft 2b, as shown in FIG. 5A, the lower end portion of the radial rolling bearing 3c {(A of FIG. ) Is a load zone (a radial load F is applied to the lower end). Since the radial rolling bearing 3c has its lower half immersed in lubricating oil, the lubrication state in the load zone becomes excessive (becomes too good), and the test time increases. On the other hand, the support bearing 5 (see FIG. 7) has a load zone at the upper end, and the lubricating oil in this load zone tends to be insufficient or exhausted. As a result, the life of the support bearing 5 is shortened, and the support bearing 5 needs to be frequently replaced. In addition, the life of the support bearing 5 may be shorter than that of the radial rolling bearing 3c, and the life test of the radial rolling bearing 3c may not be performed normally. On the other hand, when the inner ring 8a of the radial rolling bearing 3c is pressed upward in the vertical direction via the rotary shaft 2b, as shown in FIG. 5B, the upper end portion of the radial rolling bearing 3c {the same figure The portion indicated by the thick line in (B) of FIG. 4 becomes the load zone (the radial load F is added to the upper end portion). Since the lubricating oil tends to be deficient or exhausted at the upper end of the load zone, whether or not the lubricating oil splashes on the upper end of the radial rolling bearing 3c for some reason when a life test is performed. Depending on the test results, the test results may vary widely. Such a variation becomes prominent when the foreign matters 7 and 7 are mixed in the lubricating oil.

In contrast, in the present example, the two radial rolling bearing 3a, together with imparting radial load F _r in the horizontal direction to 3b, the revolution direction of each ball 25, 25, upwardly said loading zone from below Since it is set as the direction to which it passes, as shown to (A) of FIG. 6, the flow which goes to the said load zone from the bottom part of the said lubricating oil reservoir 6a can be induced in the said lubricating oil. As a result, a part of the lubricating oil can be splashed on the portion of the load zone that is not immersed in the lubricating oil, so that the lubricating oil can be distributed well and stable. Can be performed. Moreover, the foreign substances 7 and 7 mixed in the lubricating oil can be appropriately fed into the load zone. On the other hand, when the revolving direction of each of the balls 25 and 25 is a direction that passes through the load zone from the top to the bottom, as shown in FIG. 6B, the radial rolling bearing 3a ( A flow directed toward the opposite side of the load zone is induced in the circumferential direction of 3b). For this reason, the lubricating oil is insufficient in a portion of the load zone that is not immersed in the lubricating oil. Therefore, in the portion (range) where the lubricating oil is insufficient, the lubrication state changes due to the influence of slight splashes, which causes the test results to vary. In addition, an appropriate amount of foreign substances 7 and 7 cannot be sent to the load zone (the foreign substances 7 and 7 collect on the non-load zone side due to the flow of lubricating oil). Further, since the oil surface of the lubricating oil is positioned on the central axis of the rotating shaft 2a before the rotating shaft 2a is rotationally driven, the outer peripheral surface of the movable housing 4a and the pressing jig are arranged. It is possible to prevent fretting from occurring between the two surfaces by lubricating the abutting portion with the tip surface of 19. Furthermore, since at least the lower end portion of the outer peripheral surface of the rotating shaft 2a is immersed in lubricating oil, it is disposed inside the fixed housing 1a such as the radial rolling bearings 3a and 3b and the rotating shaft 2a. It is possible to suppress temperature changes of the members.

Further, in the case of this example, the vibration sensor 23 is provided between the proximal end surface of the pressing jig 19 whose front end surface is in contact with the movable housing 4 a and the steel ball 21 pressed by the pressing rod 20. It is installed on the pressing plate 22. That is, the vibration sensor 23, the order is provided so as to detect the vibration of the pressing plate 22 which is provided in series with respect to the direction of action of the radial load F _r, wherein both radial rolling bearing 3a, 3b detection accuracy of vibration Will improve. Further, the proximal end surface of the pressing jig 19 and the pressing plate 22 are brought into surface contact. From this aspect as well, the vibration detection accuracy can be improved. Further, since the vibration sensor 23 is provided outside the fixed housing 1 a, it is possible to prevent the vibration sensor 23 from being splashed with lubricating oil or being heated to high temperature by the heat generated by the heater 24.

Next, an experiment conducted for confirming the effect of the present invention will be described. In this experiment, a life test for an endurance evaluation test was performed 10 times for each of the test apparatus and the one with a different rotation direction of the rotation shaft, and the variation of the test result was verified. For Example and Comparative Example 1, the test apparatus according to one example of the embodiment of the present invention was used, and for Comparative Example 2, the test apparatus shown in FIG. 4 was used. The conditions for the life test are as follows. The rotation direction of the rotating shaft is the direction in which each rolling element constituting the test bearing passes from the lower part to the upper part in the example and the comparative example 2, and in the comparative example 1. In the same manner, the direction was passed from the top to the bottom.
Test bearing: Identification number 6208 (outer diameter = 80 mm, inner diameter = 40 mm, width = 18 mm)
Test load: 7300 N {P / C (load load / rated load) = 0.25}
Rotational speed: 4500 min ^-1
Test temperature: 100 ° C
Lubricating oil: Transmission oil Foreign matter: A predetermined amount of ferrous metal powder is mixed. Under such conditions, when the vibration value of the test bearing detected by the vibration sensor becomes twice the initial vibration value, this test bearing With a lifetime of. At that time, the test was terminated, and the presence or absence of peeling of the inner ring raceway and the outer ring raceway and the rolling surface of each rolling element was visually confirmed. The longest test time was 500 hours (Hr), and for the test bearings whose vibration value did not reach twice the initial vibration value after 500 hours, the subsequent tests were aborted. The results of the life test conducted in this way are shown in Table 1 below.

  As can be seen from Table 1 as described above, in the examples, the variation in test results is suppressed as compared with Comparative Examples 1 and 2. That is, in the case of Comparative Example 1, since the lubricating oil is insufficient in the portion of the load zone that is not immersed in the lubricating oil and the foreign matter cannot be sufficiently supplied to the test bearing, the difference between the maximum value and the minimum value of the life Is 5 times or more, and the value of the Weibull slope is as low as 1.8. Further, for each test bearing, all of the inner ring, the outer ring, and the ball were damaged, and the damaged part was also varied. Further, in the case of Comparative Example 2, the rigidity of the fixed housing with respect to the radial load applied in the horizontal direction is insufficient, and elastic deformation occurs in the side plate portion constituting the fixed jing, so that the radial load is normally applied to the test bearing. Cannot be granted. In addition, because the foreign matter could not be sufficiently supplied to the test bearings, the censoring time was exceeded in 40% of the test bearings. On the other hand, in the example, the difference between the maximum value and the minimum value of the lifetime is as small as 1.6 times, and the value of the Weibull slope is as high as 6.3. Further, the damaged part is either an inner ring or an inner and outer ring.

DESCRIPTION OF SYMBOLS 1, 1a, 1b Fixed housing 2, 2a, 2b Rotating shaft 3, 3a-3c Radial rolling bearing 4, 4a Movable housing 5, 5a Support bearing 6, 6a, 6b Lubricating oil reservoir 7 Foreign material 8, 8a Inner ring 9 Step part 10 Washer 11 Outer ring 12 Axial side wall portion 13 Circular holes 14a, 14b Support sleeve 15a, 15b Support portion 16 Piston portion 17a, 17b Width side wall portion 18 Through hole 19 Press jig 20 Press rod 21 Steel ball 22 Press plate 23 Vibration sensor 24 heater 25 ball 26 bottom plate part 27 side plate part

Claims (6)

A radial rolling bearing provided with an outer ring having an outer ring raceway on an inner peripheral surface, an inner ring having an inner ring raceway on an outer peripheral surface, and a plurality of rolling elements provided between the outer ring raceway and the inner ring raceway so as to roll freely. In order to test the bearing life of
A housing, a rotary shaft that is rotatably supported inside the housing and that externally fits the inner ring of the radial rolling bearing, a rotational driving means that rotationally drives the rotational shaft, and a radial load applied to the radial rolling bearing A test device for a radial rolling bearing comprising a load applying means for
A testing apparatus for a radial rolling bearing, wherein the housing is integrally formed as a whole.   The radial rolling bearing test device according to claim 1, wherein the housing is made of carbon steel.   A lubricating oil reservoir for storing lubricating oil for immersing a part of the radial rolling bearing is provided inside the housing, and the load applying means applies a radial load in a horizontal direction. Item 3. A radial rolling bearing test apparatus according to any one of Items 1 and 2.   The radial rolling bearing test device according to claim 3, wherein a bottom surface of the lubricating oil reservoir is a partially cylindrical concave curved surface concentric with a central axis of the rotating shaft.   The radial rolling bearing test device according to claim 4, wherein a radius of curvature of a bottom surface of the lubricating oil reservoir is 0.6 times or more and 2 times or less of an outer diameter of the radial rolling bearing.   The test apparatus for radial rolling bearings according to claim 3, wherein foreign matters are mixed in the lubricating oil.

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