JP2010096207A - Rolling bearing unit for rail vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a rolling bearing for a rail vehicle from causing electrolytic corrosion without using a ground brush and also without changing the components of the bearing. <P>SOLUTION: A rolling bearing unit for the rail vehicle is adjacently disposed with a bearing 10 for a vehicle and an electrifying rolling bearing 30 in a shaft direction, and makes the electrification property of the lubricant of the electrifying rolling bearing 30 higher than that of the lubricant of the bearing for the vehicle 10. Thus, a current only flows through the electrifying rolling bearing 30, thereby avoiding a current which is intended to flow through the bearing for the vehicle 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rolling bearing unit for a railway vehicle, and more particularly to a structure for avoiding an electric current that tends to flow through the rolling bearing for a railway vehicle.

  In railway vehicles, in addition to axle bearings for supporting axles, main motor bearings, drive device bearings, and the like are used. In the axle bearing, the inner ring is fixed to the end of the axle, and the outer ring is fixed to the inside of the axle box installed on the carriage via the shaft spring. In the case of an electric railway vehicle using a traveling rail as a return line, a current is passed from the grounding device provided on the carriage to the traveling rail via the axle and wheels via the axle bearing. Patent Document 1 describes a technique in which a grounding brush is used so that there is no risk of electrolytic corrosion of the bearing even when a large-capacity current is passed, and the maintainability is improved.

  That is, referring to FIG. 2, the axle bearing 40 is fixed to the axle box 46 in order to rotatably support the axle 42. A front lid 44 is attached to the end surface of the axle 42, and a slip ring 48 is further attached to the front lid 44. The slip ring 48 is electrically connected to the axle 42 by a pin 50. A grounding brush 54 is attached to a bracket 52 fixed to the axle box 46, and the grounding brush 54 is brought into sliding contact with a slip ring 48. The current is intended to flow from the axle box 46 to the axle 42 via the bracket 52, the grounding brush 54, the slip ring 48, and the pin 50, or vice versa, but not to the axle bearing 40. .

Patent Document 2 describes an insulating bearing used for a main motor of a railway vehicle. The insulating bearing includes an outer ring, an inner ring, a rolling element, a cage, and a resin seal, and has a volume resistivity of 2 × 10 ¹⁰ Ω · cm or more.

Patent Document 3 describes an electric corrosion prevention type rolling bearing for a motor that has been subjected to sealing treatment by spraying ceramic. The sealing agent used for sealing treatment includes an epoxy group-containing component and a curing agent, does not contain a polymerizable vinyl group-containing solvent, and the epoxy group-containing component is an epoxy group contained in one molecule. A mixture containing, as an essential component, a polyglycidyl ether compound having a number of 3 or more, and containing at least one selected from an alkylene diglycidyl ether compound and a cycloaliphatic diepoxy compound having two epoxy groups in one molecule By using a sealing agent containing 10 to 80% by weight of a polyglycidyl ether compound with respect to the entire epoxy group-containing component excluding the curing agent, the pores (gap) of the thermal spray coating can be reduced. It can be packed closely.
Japanese Patent Laid-Open No. 11-245811 JP 2007-205556 A JP 2008-069923 A

  When a current is passed through the axle bearing, electrolytic corrosion occurs between the rolling surface of the rolling elements and the raceway surface. If the current is continued to be used as it is, it may cause problems such as abnormal noise and wear. Therefore, it is necessary to interrupt or avoid the current that flows through the axle bearing.

  The grounding technology of Patent Document 1 bypasses the current through the grounding brush. However, since the grounding brush is slid on the rotating member, the trouble due to wear of the grounding brush, that is, the wear powder from the grounding brush lubricates. There is a concern that it may be mixed with the agent and, as a result, poor lubrication due to it. On the other hand, the techniques described in Patent Document 2 and Patent Document 3 both take some measures against the components of the bearing.

  An object of the present invention is to prevent electric corrosion of a rolling bearing for a railway vehicle without using a grounding brush and without changing the components of the bearing.

  In this invention, a rolling bearing for a railway vehicle and a rolling bearing for energization are arranged adjacent to each other in the axial direction, and the lubricity of the rolling bearing for energization is made higher than that of the rolling bearing for a railway vehicle. This solves the problem.

  Since no grounding brush is used, electric corrosion of rolling bearings for railway vehicles can be prevented without causing problems in the prior art using grounding brushes. Specifically, instead of sliding the installed brush, rolling using an energizing rolling bearing suppresses problems due to brush wear, that is, deterioration of lubricant due to brush wear powder. In addition, it is possible to ensure stable electrical conductivity over the long term.

  When the rolling bearing for a railway vehicle is an axle bearing, a pair of inner rings having a raceway surface on the outer periphery, a double-row outer ring having a raceway surface on the inner periphery, and a raceway surface of the inner ring and a raceway surface of the outer ring A plurality of rows of rolling elements and a cage for holding each row of rolling elements at a predetermined interval in the circumferential direction, and a bearing for an axle in which grease is sealed. The current-carrying rolling bearing is placed between the cut and the rear lid, and the current-carrying rolling bearing is disposed between the oiler and the oil-cutter via an adapter. Current flow is avoided (claim 2).

  As a means to increase the conductivity of the rolling contact bearing lubricant compared to the rolling stock rolling bearing lubricant, a metallic solid lubricant coating is applied to the rolling and raceway surfaces of the rolling contact bearing. It may be provided (Claim 3), or energized grease is used as a lubricant for the energizing rolling bearing (Claim 4), or both of them are employed.

  A contact type or non-contact type using an oil seal can be adopted as a sealing device for the energizing rolling bearing. By adopting a highly hermetic seal using an oil seal, it is possible to increase the retention of grease and to prevent foreign matters such as muddy water and dust from entering the rolling bearing for energization. Moreover, when the energizing rolling bearing is located on the shaft end side of the rolling bearing for the railway vehicle, the high sealing performance of the energizing rolling bearing contributes to the prevention of foreign matter from entering the rolling bearing for the railway vehicle at the same time. The dust prevention effect of rolling bearings for vehicles is also improved.

  The inner ring of the current-carrying rolling bearing is fixed with the shaft-side holding lid attached to the axle, and the outer ring of the current-carrying rolling bearing is held with the holding lid attached to the axle box. A labyrinth seal may be formed (claim 6). By adopting such a configuration, it is possible to improve the sealing performance, thereby improving the grease holding power, preventing dust from entering the inside of the bearing unit, and preventing dust from rolling rolling bearings for railway vehicles.

  The cage of the energizing rolling bearing is preferably made of copper alloy or resin (claims 7 and 8). By adopting such a configuration, the impact resistance and vibration resistance of the cage can be improved.

  By making the radial clearance and axial clearance of the rolling bearing for energization larger than that of the rolling bearing for railway vehicles (Claim 9), the load is supported by the rolling bearing for railway vehicles, and the energizing rolling bearing receives the load. The power supply function is assumed exclusively. By sharing the function in this way, electric corrosion specific to the railway vehicle can be effectively suppressed.

  You may make it load the light load by an elastic body from the load side of the rolling bearing for electricity supply (Claim 10). By adopting such a configuration, it is possible to suppress the sliding of the rolling elements and maintain a reliable energization action.

  According to this invention, it is possible to prevent electrolytic corrosion without using a grounding brush. In other words, a current-carrying rolling bearing is attached to the side of the rolling bearing for a railway vehicle, and the lubricity of the rolling bearing for electrification is made higher than that of the rolling bearing for a railway vehicle, thereby improving the electrical conductivity. A current selectively flows through the rolling bearing, and electric corrosion can be prevented by avoiding energization of the rolling bearing for rolling stock.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the case where it applies to a railway vehicle axle bearing is demonstrated as an example as a rolling bearing for railway vehicles.

  Referring to FIG. 1, an axle bearing is indicated generally by the numeral 10. This axle bearing 10 is a type using a double-row tapered roller bearing, and has an inner ring 12, an outer ring 14, a tapered roller 16, a cage 18, and a spacer 13. The inner ring 12 is used as a pair in the axial direction with a spacer 13 interposed therebetween, and has a raceway surface on the outer periphery. The outer ring 14 is a so-called double-row outer ring having two rows of raceways on the inner periphery. The rolling element, that is, the tapered roller 16 here, is disposed between the raceway surface of the inner ring 12 and the raceway surface of the outer ring 14 so as to be freely rollable. The tapered rollers 16 in each row are held at predetermined intervals in the circumferential direction by a cage 18.

  Sealing devices 20 are attached to openings at both ends of the outer ring 14. Various types of sealing devices 20 are known, and can be selected and adopted as appropriate. For example, a type including a stationary side member fixed to the outer ring 14 and a rotating side member fixed to the rear lid 4 and the oil drainer 6 and a seal lip extending from the stationary side member being in contact with the rotating side member. Can do.

  The pair of inner rings 12 are fitted to the end of the axle 2. The rear lid 4 and the oil drainer 6 are arranged on both sides of the pair of inner rings 12 in the axial direction. The rear lid 4 has a step for abutting and positioning the shoulder 2a of the axle 2 on the inner periphery, and a cylindrical surface for attaching the rotation side member of the seal device 20 is formed on the outer periphery. A cylindrical surface for attaching the rotation side member of the sealing device 20 is formed on the outer periphery of the oil drainer 6 in the same manner as the rear lid 4.

  The outer ring 14 is fixed to the axle box 8. In the same axle box 8, an energizing rolling bearing 30 is installed closer to the shaft end than the outer ring 14. The energizing rolling bearing 30 includes an inner ring 32, an outer ring 34, a rolling element 36, a cage 38, and a seal device 39. Although it is advantageous in terms of cost to use a standard ball bearing as the energizing rolling bearing 30, the cage 38 is made of copper alloy or resin in order to improve impact resistance and vibration resistance. Is preferred. An example of a resin that can be used in this case is a high-temperature polyamide resin (PA46).

  An adapter 22 is interposed between the inner ring 32 and the axle 2. The adapter 22 is used to prevent the peripheral parts such as the axle 2 and the oil drainer 6 from being changed when a standard ball bearing is used as the energizing rolling bearing 30. Therefore, it is not always necessary to use a separate oil drain 6 and adapter 22 as shown in the figure, and it is possible to integrate both. Further, since the axle 2 is supported exclusively by the axle bearing 10, the fit between the adapter 22 and the axle 2 and the inner ring 32 can be a light interference fit. Since the function of the adapter 22 is as described above, the material of the adapter 22 is not particularly limited as long as the material is also conductive. For example, mechanical structural carbon steel can be used.

  A spacer 24 is interposed between the outer ring 34 and the outer ring 12 of the axle bearing 10. Then, the presser lids 26 and 28 are fixed with bolts to fix the rolling bearing unit for the railway vehicle including the axle bearing 10 and the energizing rolling bearing 30 on the axle 2 in a state where the rolling bearing unit is positioned in the axial direction. More specifically, the presser lid is divided into an inner diameter side presser lid 26 and an outer diameter side presser lid 28, and the inner diameter side presser lid 26 is an end face of the inner ring 32 of the adapter 22 and the energizing rolling bearing 30. The bolt 2 is fixed to the end surface of the axle 2 with a bolt. The holding lid 28 on the outer diameter side is fixed to the axle box 8 with bolts while being in contact with the end face of the outer ring 34 of the energizing rolling bearing 30. Then, a labyrinth is formed by the outer peripheral edge of the inner diameter side presser lid 26 and the inner peripheral edge of the outer diameter side presser cover 28 to exert the action of a non-contact seal. Accordingly, the sealing performance of the energizing rolling bearing 30 is improved, the grease holding power is increased, and as a result, rain water and dust can be prevented from entering the bearing unit, and the dust bearing effect of the axle bearing 10 can be expected.

  For lubrication of the rolling bearing 30 for energization, energized grease is enclosed, or a coating of a metallic solid lubricant is formed on the raceway surfaces of the rolling elements and the race rings 32 and 34, or both of them are employed. In this way, the lubricant for the energizing rolling bearing 30 is made more conductive than the lubricant for the axle bearing 10 and is installed on the axle 20 so as to be energized, thereby avoiding energization of the axle bearing 10. Thus, the current flows exclusively through the rolling bearing 30 for energization. Specific examples of the energizing grease include KS660 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd. and Multemp L540 (“Multemp” is a registered trademark) manufactured by Kyodo Yushi Co., Ltd. Specific examples of metallic solid lubricants include lead and silver coating treatments. An electrical resistance value is used as an index of electrical conductivity. The electric resistance value is measured in a state where the bearing is rotated. For example, if it is 20 kΩ or less, it is determined that the electric conductivity is provided.

  In the conventional technique using the energizing brush, the energizing brush contacts the rotating member, so that the functional deterioration due to wear is quick. On the other hand, the energizing rolling bearing 30 is rolling, and thus stable energization for a long time. Sex can be secured.

  As the sealing device 40 of the rolling bearing 30 for energization, for example, a type using an oil seal is preferable. Adopting a highly sealable seal, such as an oil seal, increases the grease retention and prevents the entry of foreign matter such as rainwater and dust into the energizing rolling bearing 30 and, in turn, for axles. Since foreign matter intrusion to the bearing 10 side can be prevented, an improvement in the dust prevention effect of the axle bearing 10 can be expected.

  Increase the radial clearance and axial clearance of the rolling bearings for current application to be larger than that of the axle bearings. As a result, the load is supported by the axle bearing 10, and the energizing rolling bearing 30 is solely responsible for the energizing function. By sharing the function in this way, electric corrosion specific to the railway vehicle can be effectively suppressed.

  As described above, since the energizing rolling bearing 30 is exclusively responsible for the energizing function, as described above, the fit between the axle 2 and the adapter 22 and the adapter and the inner ring 32 is a light interference fit. However, if slip occurs between the inner ring 32 and the rolling element 36 and between the outer ring 34 and the rolling element 36, there is a risk of promoting wear inside the bearing or generating heat. Therefore, in order to prevent the rolling element 36 of the energizing rolling bearing 30 from slipping and to ensure that a current flows, between the outer peripheral surface of the outer ring 34 and the axle box 8 on the load side of the energizing rolling bearing 30. The elastic body 35 is interposed, and a light load is applied to the energizing rolling bearing 30. In the embodiment shown in FIG. 1, the upper side of the figure is the load side. That is, a slight radial load is applied from the axle box 8 to the outer ring 34.

  Specific examples of the elastic body 35 include a resin material having electrical conductivity and a metal spring. FIG. 1 shows an example in which the elastic body 35 is a plate-shaped resin material metal coil spring. The elastic body 35 does not have to be a ring-shaped member that exists around the entire circumference of the outer ring 34, and it is sufficient if it exists at least on the load side, that is, in a constant angle region centered around 12 o'clock in this case. Therefore, in addition to arranging a single elastic body around 12:00, a plurality of elastic bodies may be distributed over the angular region. Further, a prismatic disc spring or a cylindrical resin material leaf spring may be employed instead of the plate coil spring. In the case of a prismatic or columnar resin material, the axis may be arranged in the radial direction of the energizing rolling bearing 30. Similarly, in the case of a compression coil spring or a leaf spring, the axis is arranged in the radial direction of the energizing rolling bearing 30.

  In addition, although the rolling bearing for railway vehicles was demonstrated taking the case of the axle bearing as an example, it can be applied also to other rolling bearings for railway vehicles. For example, by providing a rolling bearing for energization on the gear case and the axle side of the driving device, it is possible to take measures against electrolytic corrosion of the rolling bearing for the driving device.

It is a longitudinal cross-sectional view of the axle bearing unit which shows an Example. It is a longitudinal cross-sectional view of the bearing for railway vehicle axles which shows the prior art.

Explanation of symbols

2 Axle 2a Shoulder 4 Rear lid 6 Oil drain 8 Shaft box 10 Axle bearing 12 Inner ring 13 Spacer 14 Outer ring 16 Tapered roller (rolling element)
18 Cage 20 Sealing device 22 Adapter 24 Spacer 26 Pressing lid (inner diameter side)
28 Pressing lid (outer diameter side)
30 Rolling bearing for energization 32 Inner ring 34 Outer ring 35 Elastic body 36 Ball (rolling element)
38 Cage 39 Sealing device

Claims (10)

  Rolling bearings for railway vehicles and rolling bearings for electrification are arranged adjacent to each other in the axial direction, and rolling stocks for rolling stock that have higher electrical conductivity than lubricants for rolling stock bearings for rolling stock. Bearing unit.   The rolling bearing for a railway vehicle includes a pair of inner rings having a raceway surface on the outer periphery, a double-row outer ring having a raceway surface on the inner periphery, and a double row disposed between the raceway surface of the inner ring and the raceway surface of the outer ring. And rolling bearings that hold the rolling elements of each row at a predetermined interval in the circumferential direction, and are bearings for axles in which grease is enclosed, and the pair of inner rings are oil drained and a rear lid. The rolling bearing unit for a railway vehicle according to claim 1, wherein the rolling bearing for energization is disposed between the oil drainer and an oil supply via an adapter.   The energizing rolling bearing includes an inner ring fixed to the axle, an outer ring fixed to the axle box, a plurality of rolling elements disposed between the inner ring and the outer ring, a cage for holding the rolling elements at a predetermined interval, and a seal. The rolling bearing unit for a railway vehicle according to claim 1 or 2, further comprising a device, wherein a coating of a metallic solid lubricant is formed on the raceway surfaces of the inner and outer rings and the rolling elements.   The rolling bearing unit for a railway vehicle according to any one of claims 1 to 3, wherein an energizing grease is used as a lubricant for the energizing rolling bearing.   The rolling bearing unit for a railway vehicle according to claim 3 or 4, wherein the energizing rolling bearing seal device uses an oil seal.   The inner ring of the current-carrying rolling bearing is fixed with a shaft-side holding lid attached to the axle, and the outer ring of the current-carrying rolling bearing is held with a holding lid attached to the axle box. The rolling bearing unit for a railway vehicle according to any one of claims 3 to 5, wherein a labyrinth seal is formed therebetween.   The rolling bearing unit for a railway vehicle according to any one of claims 3 to 6, wherein a cage of the rolling bearing for energization is made of a copper alloy.   The rolling bearing unit for a railway vehicle according to any one of claims 3 to 6, wherein a cage of the rolling bearing for energization is made of resin.   The rolling bearing unit for a railway vehicle axle according to any one of claims 1 to 8, wherein a radial clearance and an axial clearance of the energizing rolling bearing are larger than that of the rolling bearing for the railway vehicle. The rolling bearing unit for railway vehicles according to any one of claims 1 to 9, wherein a light load by an elastic body is applied to the energizing rolling bearing from a load side.

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