JP4224682B2 - Rolling bearing fixed structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rolling bearing fixing structure applied to a sealed rolling bearing (axle bearing) that supports an axle of a railway vehicle.
[0002]
[Prior art]
Currently, as a rolling bearing fixing structure for an axle of a railway vehicle, there are a fixing structure using a bolt shown in FIG. 8 and a fixing structure using a nut shown in FIG.
[0003]
In the bolt fixing structure shown in FIG. 8, a bolt hole 152 is provided in the axial end portion 151 of the axle 150 along the axial direction. A bolt 153 is screwed into the bolt hole 152 from the outside of the front lid 154 through the through hole 155 of the front lid 154. The rolling bearing 156 is fastened and fixed to the shaft end 151 of the axle 150 by screwing a bolt 153.
[0004]
In the fixing structure with nuts shown in FIG. 9, a screw portion 162 is provided on the outer diameter surface of the shaft end portion 161 of the axle 160. A nut 163 is screwed onto the screw portion 162. The rolling bearing 164 is fastened and fixed to the shaft end portion 161 of the axle 160 by screwing a nut 163.
[0005]
In the fixed structure of the rolling bearings 156 and 164 shown in FIGS. 8 and 9, it is necessary to process the bolt holes on the axle 150 and the threaded portion 162 on the axle 160, which hinders the ultrasonic flaw inspection of the axle 150 or 160. There was a possibility. Further, in the fixing structure of the bearing 164 of FIG. 9, in order to protect the screw portion 162, it is necessary to consider the processing surface such as the material of the shaft end portion 161 and heat treatment.
[0006]
Therefore, conventionally, a fixing device for an axle bearing shown in FIG. 10 has been proposed as a fixing structure that solves the above problem (see, for example, Patent Document 1).
FIG. 10 is a cross-sectional view of an essential part showing a fixing device for a rolling bearing for an axle.
[0007]
[Patent Document 1]
JP-A-60-236802 (pages 3-4, Fig. 1)
[0008]
As shown in FIG. 10, the axle bearing fixing device includes an inner ring 171 of an axle roller bearing 170 of a railway vehicle, and a presser member 173 provided on the shaft end side (left side in FIG. 10) of the axle 172. This is a structure that is fixed with a fastening bolt 175 between the positioning member 174 provided on the side opposite to the shaft end of the axle shaft 172 (right side in FIG. 10).
A first fixing member 178 is fitted on the shaft end side outer diameter surface of the axle. The first fixing member 178 is formed with a screw hole 179 that is screwed in the axial direction. The tightening bolt 175 is screwed into the screw hole 179 of the first fixing member 178 via the through hole 177 provided in the front lid 176.
[0009]
[Problems to be solved by the invention]
However, in the conventional fixing device for the axle bearing 170 described above, when an axial load is generated, the fastening bolt 175 may be directly loaded. The configuration of the fixing device for the axle bearing 170 shown in FIG. 10 has room for improvement in terms of strength because the size of the tightening bolt 175 cannot be increased.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a rolling bearing fixing structure capable of preventing an axial load from being directly applied to a fixing member such as a bolt.
[0010]
[Means for Solving the Problems]
The above object of the present invention is a rolling bearing fixing structure that includes a shaft and a rolling bearing that rotatably supports the shaft, and that fixes the inner ring of the rolling bearing to the shaft, and covers the end surface of the shaft end of the shaft. A front lid having a through-hole penetrating in the axial direction, a step formed on the shaft, a rear lid provided between an axial end surface of the inner ring of the rolling bearing, and a shaft shaft A taper ring fitted to the outer diameter surface of the end and divided in the axial cross section, and a guide ring attached to the outer diameter surface of the taper ring, the outer diameter surface of the shaft end of the shaft being the front The taper shape is formed such that the diameter increases toward the lid, the inner diameter surface of the taper ring is formed such that the diameter increases toward the front lid, and the bolt is a through hole in the front lid. Tapered by being tightened into a screw hole formed in the tapered ring through The guide ring moves to the outer diameter side and expands to the outer diameter side, the inner diameter surface of the guide ring and the outer diameter surface of the taper ring are fastened together, and one axial end of the guide ring abuts the front lid. The other axial end is in contact with the inner ring. This is achieved by a rolling bearing fixing structure.
[0011]
In this way, when an axial load is applied to the shaft from the shaft end side, this axial load is caused by the frictional force generated between the inner diameter surface of the tapering and the outer diameter surface of the shaft end, and The bolt load is reduced by the frictional force generated between the outer diameter surface of the taper ring and the inner diameter surface of the guide ring. For this reason, it can suppress that an axial load is directly applied to a volt | bolt.
[0012]
In the rolling bearing fixing structure, it is preferable that a cylindrical case fixed to the outer ring of the rolling bearing is provided, and a sealing means is provided between the outer diameter surface of the guide ring and the case.
In this way, the rolling bearing can be sealed in the case by the sealing means. This prevents dust from entering the inside of the rolling bearing from the outside, and prevents the lubricant inside the rolling bearing from flowing out to the outside.
Further, since a sealing function is added to the outer diameter surface of the guide ring, it is not necessary to separately provide a component having a sealing function, and therefore, an increase in the number of components can be suppressed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view of a principal part showing a first embodiment of a rolling bearing fixing structure according to the present invention.
[0014]
As shown in FIG. 1, the rolling bearing fixing structure of this embodiment includes an axle (shaft) 1 such as a railway vehicle and an axle rolling bearing 10 that rotatably supports the shaft 1.
A shaft end portion (left end portion in FIG. 1) 2 of the shaft 1 is formed with an outer diameter surface 2a formed in a tapered shape whose outer diameter gradually increases toward the shaft end side (left side in FIG. 1). ing. Further, a step portion 3 is formed on the shaft 1.
[0015]
The rolling bearing 10 includes a pair of inner rings 11 and an outer ring 15, and is fixed to the shaft 1 by fitting the inner diameter surface of each inner ring 11 to the outer diameter surface of the shaft 1. The pair of inner rings 11 are arranged in the axial direction (left and right in FIG. 1) with the inner ring spacer 14 interposed therebetween. Further, the rolling bearing 10 holds a plurality of cylindrical rollers 17 inserted between the pair of inner rings 11 and the outer ring 15 and a plurality of cylindrical rollers 17 in a circumferential direction so as to be freely rollable. And a device 16.
[0016]
A front lid 20 is provided on one axial end face side (shaft end portion 2 side) of the inner ring 11 in the rolling bearing 10. A rear lid 21 is provided on the inner ring 11 on the other axial end face side (the side opposite to the shaft end 2).
[0017]
The front lid 20 is provided so as to cover the end surface (left end surface in FIG. 1) of the shaft end portion 2 of the axle 1. A through hole 23 is formed in the front lid 20 so as to penetrate in the axial direction.
[0018]
The rear lid 21 is provided between an end surface of the pair of inner rings 11 opposite to the shaft end portion 2 (right side in FIG. 1) and the step portion 3 of the axle 1.
[0019]
A taper ring 24 is fitted to the outer diameter surface 2 a of the shaft end 2. The inner diameter surface 24 a of the taper ring 24 is formed in a tapered shape in which the inner diameter surface gradually expands toward the shaft end portion 2 side in accordance with the outer diameter surface 2 a of the shaft end portion 2. The taper ring 24 is formed by being divided into two by a sectional view in the axial direction. Specifically, the taper ring 24 is divided into two parts so that the minimum diameter of the inner peripheral surface 24 a is smaller than the maximum diameter of the outer diameter surface 2 a of the shaft end 2.
Further, screw holes 25 are provided in the inner peripheral surface 24a of the taper ring 24 along the axial direction. Here, the screw hole 25 is formed so as to communicate with the through hole 23 of the front lid 20 in the axial direction.
[0020]
A guide ring 22 is attached to the outer diameter surface of the taper ring 24. The guide ring 22 has one other axial end (left end surface in FIG. 1) abuts on the inner end surface (right end surface in FIG. 1) of the front lid 20, and the other axial end (right end surface in FIG. 1). Is arranged so as to abut on one axial end surface (left end surface in FIG. 1) of the inner ring 11 on the left side in FIG.
[0021]
One end of a cylindrical case 13 is fixed to both ends of the inner surface of the outer ring of the rolling bearing 10 by fitting.
A sealing seal 12 functioning as a sealing means is provided between the inner surface of one of the cases 13 (left side in FIG. 1) and the outer diameter surface 22a of the guide ring 22.
A sealing seal 12 that functions as a sealing means is also interposed between the inner surface of the other side of the case 13 (the right side in FIG. 1) and the outer peripheral surface 21a of the rear lid 21.
[0022]
Thus, by providing the sealing seals 12 inside the case 13, dust intrusion into the axle bearing 10 from the outside can be prevented. Further, the lubricant sealed inside the rolling bearing 10 is prevented from flowing out. Furthermore, since the sealing function is added to the outer diameter surface of the guide ring, an increase in the number of parts can be suppressed.
The case 13 may be fixed by being fitted to both end portions of the outer diameter surface of the outer ring 15.
[0023]
In the fixing structure of the rolling bearing 10 of the present embodiment, a fixing bolt (bolt) 26 is inserted from the outside of the front lid 20 (left side in FIG. 1) into the through hole 23 of the front lid 20, and the detent washer 27 is attached. Via the screw hole 25 of the taper ring 24. By tightening the fixing bolt 26, the taper ring 24 moves along the outer diameter surface 2a of the shaft end 2 to the shaft end 2 side (left side in FIG. 1). Here, since the taper ring 24 is divided, the taper ring 24 expands toward the outer diameter side as the diameter of the shaft end portion 2 moves toward the larger side. That is, by tightening the fixing bolt 26, the taper ring 24 is fitted to the outer diameter surface of the shaft end portion 2 in a state where the taper ring 24 is expanded to the outer diameter side.
[0024]
At this time, the inner diameter surface 24a of the taper ring 24 and the outer diameter surface 2a of the shaft end portion 2 are tapered and in surface contact with each other. A frictional force is generated between the outer surface 2a and the outer surface 2a.
[0025]
Further, since the taper ring 24 extends to the outer diameter side, the outer diameter surface 24b of the taper ring 24 and the inner diameter surface 22b of the guide ring 22 are fastened together. For this reason, a frictional force is also generated between the outer diameter surface 24 b of the taper ring 24 and the inner diameter surface 22 b of the guide ring 22.
For this reason, the position of the taper ring 24 in the axial direction is more firmly fixed by the frictional force on the inner diameter surface 24a and the outer diameter surface 24b.
[0026]
In this embodiment, when an axial load is applied from the shaft end 2 side of the axle 1, the axial direction directly applied to the fixing bolt 26 by the frictional force generated on the inner diameter surface 24 a and the outer diameter surface 24 b of the taper ring 24. There is an effect to reduce the load.
[0027]
In order to confirm the effect of the above embodiment, when an axial load is generated on the shaft end 2 side of the axle 1 using the fixing structure of the above embodiment, a tensile force (bolt tension) applied to the fixing bolt 26 is applied. The measurement was performed using the experimental apparatus 30 shown in FIG.
FIG. 2 is a schematic cross-sectional view showing an experimental apparatus for measuring the bolt tension applied to the fixing bolt, and FIG. 3 shows the bolt tension (N) with respect to the axial load (kN) measured by the experimental apparatus of FIG. ), And FIG. 4 is a graph showing changes in the tensile strength of the fixing bolts measured using the experimental apparatus of FIG. In FIG. 4, the vertical axis represents stress (N / mm ² ), and the horizontal axis represents t (time).
[0028]
Referring to FIG. 2, in the experimental apparatus 30, an inner ring 32 that is relatively free to move in the axial direction with respect to the dummy shaft 31 is fitted into the dummy shaft 31, and has a taper ring 33 and a guide ring. 34 and the lid 35 are attached in the same state as in the above embodiment, and are fastened with fixing bolts 36. An axial load in the direction of arrow W in the figure is applied to the dummy shaft 31 in a state where the inner ring 32 is supported by the support base 37 from the outside. The fixing bolt 36 has a structure in which the taper ring 33 is tightened by being inserted into the through-holes 23 of the front lid 20 arranged at four places on the circumference, and the bolts A, B, C and D are Using. And the change of the bolt tension with respect to the axial load in each bolt was measured. The results are shown in FIG.
[0029]
As shown in FIG. 3, even when the inner ring 32 does not have a tightening allowance, there was hardly any change in the tensile force (bolt tension) of the fixing bolt 36 with an increase in the axial load. For this reason, it was found that the axial load was not directly applied to the fixing bolt 36.
[0030]
Moreover, the strength and looseness of the fixing bolt were examined from the above experimental results. Specifically, JIS B 1180 M10-6g was used as the fixing bolt, and the strength classification was equivalent to 8.8 (JIS B 1051). As the mechanical properties of the fixing bolt, the tensile strength is 830 N / mm ² , the yield strength of permanent elongation 0.2% is 660 N / mm ² , and the guaranteed load stress without permanent elongation is 600 N / mm ^2. It is.
[0031]
A case was assumed in which an axial load of 39 kN was applied to the four fixing bolts in a state where the inner ring and the shaft were tightly fitted and the four fixing bolts were tightened with a torque of 58.8 N × m. When tightened with a torque of 58.8 N × m, the fixing bolt had an average tightening force (axial force) of about 21600 N and a stress of about 380 N / mm ² .
[0032]
When an axial load was applied, there was almost no change in the tightening force (axial force). On the other hand, when the load of the axial load is removed, about 735 N as the axial force and about 13 N / mm ² as the stress act on the fixing bolt as the variation. In addition, if the temperature is repeatedly applied to the outer peripheral surface of the guide ring in a cycle of 48 ° C. → 120 ° C. → 48 ° C., the maximum tightening force (axial force) is about 880 N and the stress is about 16 N / mm ² is fixed as the fluctuation. Acts on the bolt. The result is shown in FIG.
As shown in FIG. 4, it was confirmed that there was no problem in strength of the fixing bolt.
[0033]
Next, the looseness of the fixing bolt was measured using an experimental apparatus 40 shown in FIG.
That is, FIG. 5 is a schematic sectional view showing an experimental apparatus for measuring the looseness of the fixing bolt, and FIG. 6 is a graph showing a change in bolt tension in the temperature cycle measured by the experimental apparatus of FIG.
[0034]
Referring to FIG. 5, in the experimental apparatus 40, an inner ring 42 is fitted on the shaft 41, and a taper ring 43, a guide ring 44, and a lid 45 are attached in the same state as in the above embodiment, and a strain gauge Fastened with a fixing bolt 47 with 46. A band heater 48 is attached to the outer peripheral surface 44 a of the guide ring 44. Further, a thermocouple 49 for temperature measurement is inserted into the shaft 41, the taper ring 43 and the guide ring 44.
[0035]
As the tightening torque of the fixing bolt 47, measurement was performed with three types of 19.6 N × m, 39.2 N × m, and 58.8 N × m. Further, as a temperature change condition, the band heater 48 was used to repeatedly act on the outer peripheral surface 44a of the guide ring 44 at a temperature cycle of 48 ° C → 120 ° C → 48 ° C. A decrease in tightening force (axial force) of the fixing bolt 47 at that time was measured by the strain gauge 46 of the fixing bolt 47.
As a result, as shown in FIG. 6, the fastening force (axial force) of the fixing bolt 47 after the experiment is maintained at about 95% of the axial force at the time of fastening, and the fixing bolt caused by the temperature change. It was found that there was almost no 47 slack.
[0036]
As described above, according to the rolling bearing fixing structure of the above-described embodiment, the fixing bolt 26 is connected to the taper ring 24 from the outside of the front lid 20 (left side in FIG. 1) through the through hole 23 of the front lid 20. By being screwed into the screw hole 25, the outer diameter surface 24 b of the taper ring 24 and the guide ring are formed between the tapered outer diameter surface 2 a of the shaft end 2 of the axle 1 and the inner diameter surface 24 a of the taper ring 24. A frictional force is generated between the inner diameter surface 22 b of 22. Further, both end surfaces of the guide ring 22 in the axial direction are in contact with the front lid 20 and the inner ring 11 of the rolling bearing 10, respectively.
[0037]
Therefore, even when an axial load is applied from the shaft end 2 or when an axial load is generated due to a frictional force generated by the screwing of the fixing bolt 26, the axial load is guided to the tapering 24 and the guide. It can be carried on the ring 22, and it can be suppressed that an axial load is directly applied to the fixing bolt 26. Further, loosening of the fixing bolt 26 due to temperature change can be prevented.
Furthermore, by providing the sealing seal 12 on the outer diameter side of the guide ring 22, an increase in the number of parts can be suppressed.
[0038]
FIG. 7 shows a second embodiment according to the present invention. In the embodiments described below, members having the same configuration / action as those already described are denoted by the same or corresponding reference numerals in the drawings, and description thereof is simplified or omitted.
The fixed structure of the rolling bearing of this embodiment has the same configuration as that of the first embodiment except that it is applied to the sealed cylindrical rolling bearing 50. With this configuration, the same effect as described above can be obtained.
[0039]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a rolling bearing fixing structure capable of preventing an axial load from being directly applied to a fixing member such as a bolt.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part showing a rolling bearing fixing structure according to a first embodiment of the present invention.
FIG. 2 is a schematic sectional view showing an experimental apparatus for measuring a tensile force (bolt tension) applied to a fixing bolt.
FIG. 3 is a graph showing changes in bolt tension measured by the experimental apparatus of FIG. 2;
4 is a graph showing changes in tensile strength of fixing bolts measured using the experimental apparatus of FIG. 2. FIG.
FIG. 5 is a schematic cross-sectional view showing an experimental apparatus for measuring the looseness of fixing bolts.
6 is a graph showing a change in bolt tension in a temperature cycle measured by the experimental apparatus shown in FIG. 5. FIG.
FIG. 7 is a cross-sectional view of a main part showing a rolling bearing fixing structure according to a second embodiment of the present invention.
FIG. 8 is a cross-sectional view of an essential part showing an example of a conventional structure for fixing an axle bearing of a railway vehicle.
FIG. 9 is a cross-sectional view of a main part showing another example of a conventional structure for fixing an axle bearing of a railway vehicle.
10 is a cross-sectional view of a principal part showing a rolling bearing fixing device disclosed in Patent Document 1. FIG.
[Explanation of symbols]
1 axle (axle)
2 Shaft end 2a Tapered outer surface 10 Axle bearing 11 Inner ring 12 Sealing means (sealing seal)
13 Case 14 Inner ring spacer 15 Outer ring 16 Cage 17 Cylindrical roller 20 Front cover 21 Rear cover 21a Outer surface 22 Guide ring 22a Outer surface 22b Inner surface 23 Through hole 24 Taper ring 24a Inner surface 24b Outer surface 25 Screw hole 26 Fixing bolt 27 Non-turn washer

Claims (2)

A rolling bearing fixing structure comprising a shaft and a rolling bearing that rotatably supports the shaft, and fixing an inner ring of the rolling bearing to the shaft,
A front lid provided so as to cover the end face of the shaft end portion of the shaft, and having a through hole penetrating in the axial direction;
A rear lid provided between the step formed on the shaft and the axial end surface of the inner ring of the rolling bearing;
A taper ring that is fitted to the outer diameter surface of the shaft end portion of the shaft and divided in an axial view section;
A guide ring attached to the outer diameter surface of the taper ring,
The outer diameter surface of the shaft end portion of the shaft has a tapered shape formed so that the diameter increases toward the front lid, and the inner diameter surface of the taper ring increases in diameter toward the front lid. An outer diameter side while the taper ring is moved to the front lid side by being tightened to a screw hole formed in the taper ring through the through hole of the front lid. The inner diameter surface of the guide ring and the outer diameter surface of the tapered ring are fastened together, and one axial end of the guide ring abuts the front lid, and the other axial end. A structure for fixing a rolling bearing, wherein a portion is in contact with the inner ring. 2. The rolling bearing according to claim 1, wherein a cylindrical case fixed to the outer ring of the rolling bearing is provided, and a sealing means is provided between the outer diameter surface of the guide ring and the case. Fixed structure.

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