JP2020050260A - Railway vehicle center pin, railway vehicle truck, and method of manufacturing railway vehicle center pin - Google Patents

Abstract

To provide a railway vehicle center pin, a railway vehicle truck, and a method of manufacturing the railway vehicle center pin that can facilitate manufacturing process and secure sufficient mechanical strength.SOLUTION: A center pin 10 connects a vehicle body A of a railway vehicle and a truck frame 2 arranged below the vehicle body A. The center pin 10 includes a cylindrical main body part 30, a flange part 31 protruding more than an outer surface 30e of the main body part 30 at a lower end part 30c of the main body part 30, a stopper receiving part 32 connected to the outer surface 30e of the main body part 30 and receiving a stopper 18 for regulating the displacement of the main body part 30, and a damper receiving part 33 connected to the outer surface 30e of the main body part 30 and receiving a damper 19 for relaxing the vibration of the main body part 30. The main body part 30 and the flange part 31 form an integrally forged object. The stopper receiving part 32 and the damper receiving part 33 respectively form a forged object and the stopper receiving part 32 is welded to the outer surface 30e of the main body part 30.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a center pin for a railway vehicle, a bogie for a railway vehicle, and a method for manufacturing a center pin for a railway vehicle.

  For example, Patent Documents 1 and 2 disclose a bogie for a railway vehicle. The bogie for a railway vehicle includes a bogie frame on which wheels are mounted, and a traction device that connects a vehicle body of the railway vehicle and the bogie frame and transmits a longitudinal force applied to the bogie frame to the vehicle body. The traction device has a traction link connecting a lower end of a center pin hanging from a bottom of the vehicle body and a bogie frame. The center pin is, for example, a cylindrical main body extending downward from the bottom of the vehicle body, a flange protruding from an upper end of the main body, and being fastened to the bottom of the vehicle body by a fastening member, and a main body and a flange. It is configured to include a plurality of ribs and the like provided on the outer surface of the main body so as to be connected.

JP 2010-285071 A Japanese Patent No. 6034254

  In a conventional bogie for railway vehicles, the components of the center pin such as the main body and the flange are connected to each other by welding. However, when the components are joined by welding, the number of welding points increases and the welding position becomes complicated depending on the number and shape of the components, and the manufacturing process may be complicated. In addition, when welding distortion occurs, it is necessary to correct the displacement of each component due to the welding distortion. Furthermore, since stress tends to concentrate on the welded portion at the connecting position of each component, it is necessary to ensure the mechanical strength of the center pin.

  As a method of forming each component of the center pin, casting may be used in addition to welding. However, when forming each component by casting, a bubble mark called a so-called burrow may be formed on the surface of these components. When a bubble mark is generated, a removal operation is required. However, it is difficult to specify in advance whether or not the bubble mark is generated and the position where the bubble mark is generated.

  The present invention has been made in order to solve the above-mentioned problems, and is a railway vehicle center pin, a railway vehicle bogie, and a railway vehicle center pin capable of simplifying a manufacturing process and achieving sufficient mechanical strength. It is an object of the present invention to provide a method for producing the same.

  The center pin for a railway vehicle according to one aspect of the present invention is a center pin for a railway vehicle that connects a vehicle body of a railway vehicle and a bogie frame disposed below the vehicle body, and includes a cylindrical main body, and a main body. A flange portion that protrudes from the outer surface of the main body at one end thereof, a stopper receiving portion that is coupled to the outer surface of the main body and receives a stopper that restricts displacement of the main body, and an outer surface of the main body. And a damper receiving portion for receiving a damper for alleviating vibration of the main body portion, wherein the main body portion and the flange portion are integrally forged, and both the stopper receiving portion and the damper receiving portion are forged bodies. The stopper receiving portion is welded to the outer surface of the main body.

  In this railcar center pin, the main body and the flange are formed as an integral forged body, and the stopper receiving part and the damper receiving part, which are also forged, are welded to the main body. This makes it possible to simplify the shapes of the main body and the flange. By welding the stopper receiving portion to the simplified main body, it is possible to avoid an increase in welding locations and a complicated welding position. it can. Therefore, the manufacturing process is simplified. In addition, the concentration of stress on the welding portion can be reduced, and the mechanical strength of the center pin can be secured. Further, in this center pin for a railway vehicle, since the main body, the flange, the stopper receiving portion, and the damper receiving portion are all forged bodies, unlike the case where these are formed by casting, there is also a problem of bubble marks. Absent. Therefore, there is no need to remove the bubble traces, and simplification of the manufacturing process is ensured.

  In the above-described center pin for a railway vehicle, the stopper receiving portion and the damper receiving portion are an integral forged body, and the damper receiving portion may be coupled to the outer surface of the main body via the stopper receiving portion. . In this case, by welding the stopper receiving portion and the damper receiving portion, which are integral forgings, to the main body, it is possible to more reliably avoid an increase in welding locations and a complicated welding position.

  In the railcar center pin described above, the flange portion is provided with a plurality of insertion holes through which a fastening member used for coupling to the vehicle body is inserted, and the peripheral portion of the flange portion is located at a position between the respective insertion holes. A concave portion that is depressed toward the center of the flange portion may be provided. Thus, the area of the flange portion can be suppressed while securing a region required for fastening the fastening member in the flange portion. Therefore, the weight of the railcar center pin can be reduced.

  A railway vehicle bogie according to one aspect of the present invention is configured such that a railway vehicle center pin, a traction device having a traction link connecting a bogie frame and the other end of a main body, and a stopper receiving portion are provided. A stopper is provided, and a damper is provided so as to face the damper receiving portion.

  The railcar bogie simplifies the manufacturing process and ensures sufficient mechanical strength by the above-described railcar center pin. Therefore, the reliability of the bogie for railway vehicles can be improved.

  A method of manufacturing a center pin for a railway vehicle according to one aspect of the present invention is a method of manufacturing a center pin for a railway vehicle that connects a vehicle body of a railway vehicle and a bogie frame arranged below the vehicle body, and includes a cylindrical shape. A main body and a flange portion that protrudes from the outer surface of the main body at one end of the main body are integrally formed by forging, and a stopper receiving portion that receives a stopper that restricts displacement of the main body, and a vibration of the main body. A damper receiving portion for receiving the damper to be relaxed is formed by forging, and the stopper receiving portion is welded to the outer surface of the main body by welding.

  In this method of manufacturing a center pin for a railway vehicle, in the center pin for a railway vehicle, a main body portion and a flange portion are integrally formed by forging, and then a stopper receiving portion and a damper receiving portion also formed by forging are attached to the main body portion. Welded. This makes it possible to simplify the shapes of the main body and the flange, and by welding the stopper receiving portion to the simplified main body, it is possible to avoid an increase in welding locations and a complicated welding position. it can. Therefore, the manufacturing process is simplified. In addition, the concentration of stress on the welding portion can be reduced, and the mechanical strength of the center pin can be secured. Furthermore, in this railcar center pin, since the main body, the flange, the stopper receiving part, and the damper receiving part are all formed by forging, unlike the case where these are formed by casting, there is also a problem of bubble marks. Absent. Therefore, there is no need to remove the bubble traces, and simplification of the manufacturing process is ensured.

  In the above-described method of manufacturing the center pin for a railway vehicle, the stopper receiving portion and the damper receiving portion are integrally formed by forging, and the damper receiving portion is connected to the outer surface of the main body via the stopper receiving portion. In this case, by welding the stopper receiving portion and the damper receiving portion integrally formed by forging to the main body portion, it is possible to more reliably avoid an increase in welding locations and a complicated welding position.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the center pin for rail vehicles, the bogie for rail vehicles, and the center pin for rail vehicles which can implement | achieve simplification of a manufacturing process and sufficient guarantee of mechanical strength is provided.

FIG. 1 is a side view of a bogie for a railway vehicle according to one embodiment of the present invention. FIG. 2 is a side view showing a part of the bogie for a railway vehicle shown in FIG. 1 in an enlarged manner. FIG. 3 is a perspective view of a center pin for a railway vehicle according to one embodiment of the present invention. FIG. 4 is a flowchart illustrating an example of a method of manufacturing a center pin for a railway vehicle. FIG. 5A is a perspective view of a center pin for a railway vehicle according to a comparative example. FIG. 5B is a perspective view of the railcar center pin shown in FIG. 5A viewed from another angle. FIG. 6 is a diagram showing a stress distribution of the center pin for a railway vehicle. FIG. 7 is a diagram showing a stress distribution of the center pin for a railway vehicle. FIG. 8 is a diagram showing a stress distribution of the center pin for a railway vehicle. FIG. 9 is a stress limit diagram showing a result of stress analysis of a center pin for a railway vehicle. FIG. 10 is a stress limit diagram showing a stress analysis result of the center pin for a railway vehicle according to the comparative example.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same or corresponding elements have the same reference characters allotted, and redundant description will not be repeated.

  FIG. 1 is a side view of a railway vehicle bogie 1 (hereinafter, simply referred to as “bogie 1”) according to an embodiment of the present invention. FIG. 2 is a side view showing a part of the cart 1 shown in FIG. 1 in an enlarged manner. FIG. 2 shows a part of the cart 1 as a cross-sectional view. Each drawing shows an XYZ coordinate system for easy understanding. In the following description, the direction in which the vehicle body A (see FIG. 2) travels is referred to as a traveling direction (front-rear direction) X, the direction intersecting with the traveling direction X and indicating the left and right of the vehicle body A is referred to as a left-right direction Y, and the traveling direction X And a direction intersecting the left-right direction Y and indicating the vertical direction (height) of the vehicle body A is defined as a vertical direction Z. In FIG. 2, a part of the bottom of the vehicle body is shown as a vehicle body A.

  The trolley 1 is, for example, a bolsterless trolley, and is disposed below the vehicle body A of the railway vehicle in the vertical direction Z. The bogie 1 includes a bogie frame 2, a wheel axle 5 having wheels 3 attached to an axle 4, an axle box 7 containing a bearing 6 for rotatably supporting the axle 4 of the axle 5, an axle box 7 and a bogie frame 2 , An air spring 9 disposed above the bogie frame 2, and a railcar center pin 10 mounted below the body A (hereinafter simply referred to as "center pin 10"). ), A pair of stoppers 18 provided on both sides of the center pin 10 in the left-right direction Y, and a pair of stoppers 18 provided on both sides of the center pin 10 in the left-right direction Y. And a damper 19 to be provided.

  The bogie frame 2 has a substantially H shape when viewed from the vertical direction Z of the vehicle body A. The bogie frame 2 includes a pair of side beams 11 extending in the traveling direction X, a pair of horizontal beams 12 extending in the left-right direction Y and connecting central portions of the pair of side beams 11 in the traveling direction X, and a traveling direction. It comprises a pair of auxiliary beams (not shown) extending in X and connecting central portions of the pair of horizontal beams 12 in the left-right direction Y. Before and after the bogie frame 2 in the traveling direction X, wheel sets 5 supporting the bogie frame 2 are integrally disposed via bearings 6.

  The air spring 9 is a device that improves the ride comfort of the railway vehicle by reducing the vibration of the vehicle body A in the vertical direction Z. The air spring 9 is provided between the bogie frame 2 and the vehicle body A in the vertical direction Z, and supports the vehicle body A. The center pin 10 is attached to a lower part of the vehicle body A in the up-down direction Z, and hangs from the lower part of the vehicle body A so as to pass between a pair of cross beams 12 of the bogie frame 2. The center pin 10 is made of a metal material such as carbon steel or an aluminum alloy. The detailed configuration of the center pin 10 will be described later.

  The traction device 13 is a device that transmits the longitudinal force applied to the bogie frame 2 in the traveling direction X to the vehicle body A through the wheel set 5. The traction device 13 has a traction link 14 that connects the bogie frame 2 and the lower end 10 a of the center pin 10. The towing link 14 is a connecting member extending along the traveling direction X, and includes a main body 15 extending along the traveling direction X, a tip 16 located at one end of the main body 15 in the traveling direction X, And a base end 17 located at the other end in the traveling direction X. The tip 16 is provided so as to project toward one of the cross beams 12. The base end portion 17 is pivotally supported by the bogie frame 2 on the other cross beam 12 side so that the front end portion 16 can swing. The traction link 14 having such a configuration is also called a single link.

  The pair of stoppers 18 are members that regulate the displacement of the center pin 10 attached to the lower part of the vehicle body A in the left-right direction Y so as not to exceed a certain amount, and are made of, for example, an elastic body such as rubber. For example, the pair of stoppers 18 protrude from inner side surfaces located inside the left-right direction Y in the above-described pair of auxiliary beams, and face each other at a predetermined interval in the left-right direction Y. As shown in FIG. 2, each stopper 18 has, for example, a rectangular shape when viewed from the left-right direction Y.

  The damper 19 is a device that improves the riding comfort of a railway vehicle by reducing vibration in the left-right direction Y of the center pin 10 attached to the vehicle body A. The damper 19 generates a damping force in accordance with the relative vibration of the center pin 10 with respect to the bogie frame 2 in the left-right direction Y. The damper 19 is provided between one auxiliary beam of the bogie frame 2 and the vehicle body A in the vertical direction Z, for example. The damper 19 is disposed above one stopper 18 in the vertical direction Z. That is, the damper 19 is arranged at a position overlapping with one of the stoppers 18 when viewed from the vertical direction Z. The damper 19 has a cylindrical main body 19a extending in the left-right direction Y, and a cylindrical mandrel 19b provided at the tip of the main body 19a and extending in the traveling direction X.

  Subsequently, the configuration of the center pin 10 will be described in more detail with reference to FIGS. The center pin 10 includes a cylindrical main body 30 extending in the vertical direction Z, a flange 31 provided at an upper end 30 d (one end) of the main body 30 on the vehicle body A side in the vertical direction Z, and a main body 30. A pair of stopper receiving portions 32 provided on both sides in the left-right direction Y of the main body 30 and a damper receiving portion 33 provided on one side in the left-right direction Y of the main body 30.

  The main body 30 is a forged body integral with the flange 31. The main body 30 includes a constant diameter portion 30a having a substantially constant diameter, and a diameter increasing portion 30b gradually increasing in diameter from the constant diameter portion 30a toward the flange portion 31 side. The constant diameter portion 30a is located on the lower end 30c (the other end) side of the main body 30 in the vertical direction Z, and the enlarged diameter portion 30b is located on the upper end 30d side of the main body 30. Neither the constant diameter portion 30a nor the enlarged diameter portion 30b is provided with a reinforcing member such as a rib, and the peripheral surfaces of the constant diameter portion 30a and the enlarged diameter portion 30b have a smoothly continuous shape.

  The flange portion 31 has a rectangular plate shape extending in the traveling direction X and the left-right direction Y. The flange portion 31 is formed to protrude from the outer surface 30e of the main body 30 in the traveling direction X and the left-right direction Y at the upper end portion 30d, and is provided continuously along the circumferential direction of the outer surface 30e. The four corner portions of the flange portion 31 are thicker than the other portions, and each of these corner portions is inserted with a fastening bolt 40 (fastening member) used for coupling with the vehicle body A. A hole 31a is provided. The insertion hole 31a penetrates each corner of the flange portion 31 in the up-down direction Z, and the center pin 10 is fastened to the vehicle body A by each fastening bolt 40 passing through the insertion hole 31a.

  A plurality of (four in the present embodiment) concave portions 31c that are recessed toward the center of the flange portion 31 are formed in the peripheral portion 31b of the flange portion 31. The concave portion 31c is provided at a position between the insertion holes 31a provided at the four corners of the flange portion 31, respectively. Specifically, the concave portion 31c is provided at the center of each of four sides forming four corners in the peripheral portion 31b of the flange portion 31. The shape of the concave portion 31c is not particularly limited, but the concave portion 31c of the present embodiment has a gentle curved shape toward the center side of the flange portion 31 in a plan view of the flange portion 31.

    The pair of stopper receiving portions 32 face the pair of stoppers 18 in the left-right direction Y, respectively, and receive the pair of stoppers 18 in the left-right direction Y, respectively. Each stopper receiving portion 32 is a rectangular plate-shaped forging extending in the traveling direction X and the vertical direction Z, and is joined to the outer surface 30 e of the constant diameter portion 30 a of the main body 30 by welding. In the present embodiment, a finish (polishing) using a grinder or the like may be applied to the welded portion W, which is a connection portion between each stopper receiving portion 32 and the outer surface 30e. In this case, it is possible to make the welded portion W inconspicuous with respect to other portions.

  The damper receiving portion 33 is opposed to the damper 19 in the left-right direction Y, and receives the damper 19 in the left-right direction Y. The damper receiving portion 33 is a forged body integrated with one of the pair of stopper receiving portions 32. That is, the damper receiving portion 33 is connected to the outer surface 30e of the constant diameter portion 30a of the main body 30 by welding via the one stopper receiving portion 32. Therefore, the damper receiving portion 33 is provided between the vehicle body A and one of the auxiliary beams in the vertical direction Z in a state where the damper receiving portion 33 is coupled to the main body portion 30. The damper receiving portion 33 is provided at an upper end portion 32 a of the one stopper receiving portion 32 in the vertical direction Z. The damper receiving portion 33 has a pair of convex portions 33a projecting from both ends along the traveling direction X at the upper end portion 32a of the one stopper receiving portion 32. The convex portions 33a are arranged at predetermined intervals in the traveling direction X. A receiving surface 33b for receiving the mandrel 19b of the damper 19 is provided at the upper end of each projection 33a. The receiving surface 33b is a surface extending along the traveling direction X and the vertical direction Z, and faces the side surface of the mandrel 19b in the left-right direction Y.

  A method of manufacturing the center pin 10 having the above configuration will be described with reference to FIG. FIG. 4 is a flowchart illustrating an example of a method for manufacturing the center pin 10. As shown in FIG. 4, the method for manufacturing the center pin 10 according to the present embodiment includes a first forming step S1, a second forming step S2, and a welding step S3. In the first forming step S1, the main body 30 and the flange 31 are integrally formed by forging. In the second forming step S2, one stopper receiving portion 32 and the damper receiving portion 33 are integrally formed by forging, and the other stopper receiving portion 32 is formed by forging. The order of the first forming step S1 and the second forming step S2 does not matter.

  In the welding step S3 following these forming steps S1 and S2, the other stopper receiving part 32 formed by forging, the one stopper receiving part 32 and the damper receiving part 33 formed integrally by forging are also integrated by forging. The main body 30 and the flange 31 are formed by welding. In the welding step S3, one stopper receiving portion 32 and the damper receiving portion 33 formed integrally are welded to the outer surface 30e of the constant diameter portion 30a of the main body 30 from one side in the left-right direction Y, and the other stopper is formed. The receiving portion 32 is welded to the outer surface 30e of the constant diameter portion 30a of the main body 30 from the other side in the left-right direction Y. Although there is no particular limitation on the welding method, for example, arc welding or laser welding can be used.

  The effects obtained by the method of manufacturing the center pin 10, the trolley 1, and the center pin 10 according to the present embodiment described above will be described. In the present embodiment, the main body 30 and the flange 31 are formed as an integral forged body, and the pair of stopper receiving portions 32 and the damper receiving portions 33, which are also forged bodies, are welded to the main body 30. Accordingly, the shapes of the main body 30 and the flange 31 can be simplified, and the stopper receiving portion 32 is welded to the simplified main body 30 to increase the number of welding locations and the welding position. Complexity can be avoided. Therefore, the manufacturing process is simplified. In addition, the concentration of stress on the welded portion can be reduced, and the mechanical strength of the center pin 10 can be secured. Further, in the center pin 10, the main body portion 30, the flange portion 31, the stopper receiving portion 32, and the damper receiving portion 33 are all forged, so that unlike the case where these are formed by casting, there is also a problem of bubble marks. Does not occur. Therefore, there is no need to remove the bubble traces, and simplification of the manufacturing process is ensured.

  In the present embodiment, the one stopper receiving portion 32 and the damper receiving portion 33 are an integral forged body, and the damper receiving portion 33 is connected to the outside of the fixed diameter portion 30a of the main body 30 via the one stopper receiving portion 32. It is connected to the side surface 30e. In this case, by welding one of the stopper receiving portion 32 and the damper receiving portion 33, which are integral forgings, to the main body 30, an increase in the number of welding locations and a complicated welding position can be more reliably avoided.

  In the present embodiment, the flange portion 31 is provided with a plurality of insertion holes 31a through which the fastening bolts 40 used for coupling with the vehicle body A are inserted, and the peripheral portion 31b of the flange portion 31 is provided between the respective insertion holes 31a. A concave portion 31c that is depressed toward the center of the flange portion 31 is provided at a predetermined position. Thereby, the area of the flange portion 31 can be suppressed while securing a region required for fastening the fastening bolt 40 in the flange portion 31. Therefore, the weight of the center pin 10 can be reduced.

  As described above, the truck 1 according to the present embodiment includes the center pin 10, the towing device 13 having the towing link 14 connecting the bogie frame 2 and the lower end 30 c of the main body 30, and the stopper receiving portion 32. And a damper 19 arranged so as to face the damper receiving portion 33. The bogie 1 has the center pins 10 to simplify the manufacturing process and ensure sufficient mechanical strength. Therefore, the reliability of the cart 1 can be improved.

  Subsequently, the effect confirmation test of the present invention will be described.

  The effect confirmation test is an analysis of the stress distribution of the center pin when a constant load is applied to the center pin for the example and the comparative example. The center pin 10 according to the embodiment is a model in which the main body 30 and the flange 31 are integrally formed by forging (see FIGS. 2 and 3). This is a model in which the flange portion 131 is joined by welding (see FIGS. 5A and 5B).

  In the center pin 100, the main body 130 does not have the enlarged diameter portion 30b, unlike the main body 30 according to the embodiment, and has a substantially constant diameter. Unlike the flange portion 31 according to the embodiment, the flange portion 131 does not have the concave portion 31c. In the center pin 100, a plurality of ribs 140 for reinforcing the main body 130 and the flange 131 are connected to the main body 130 and the flange 131 by welding. Each rib 140 is arranged along the circumferential direction of the main body 130.

  In the center pin 100, unlike the center pin 10 according to the embodiment, the damper receiving portion 133 is separated from one stopper receiving portion 132. The damper receiving portion 133 is directly connected to the main body portion 130 by welding above the one stopper receiving portion 132. 5A and 5B show a welded portion W of each component constituting the center pin 100. FIG.

  In this test, stress analysis was performed by FEM (finite element method) for each of the center pin 10 according to the example and the center pin 100 according to the comparative example. The test method conformed to the load test method specified in “JIS E4207”. Specifically, a traction force, a left-right movement damper force, and a left-right movement stopper force are applied to the center pins 10 and 100 in a state where the flange portions 31 and 131 are constrained in the vertical direction Z. The traction force is a load applied to the lower end 10 a of the center pins 10 and 100 by the bogie frame 2 and the traction device 13. Regarding the load direction of the traction force, a traction direction along the traveling direction X is called a pulling direction, and a direction opposite to the pulling direction is called a pushing direction.

  The left and right dynamic damper force is a load applied by the damper 19 to the receiving surfaces 33b of the damper receiving portions 33 and 133. Regarding the left and right dynamic damper force, a load direction from one side in the left and right direction Y to the other side is called a pushing direction, and a direction opposite to the pushing direction is called a pulling direction. The lateral movement stopper force is a load applied to each of the pair of stopper receiving portions 32 and 132 by the pair of stoppers 18. Regarding the lateral movement stopper force applied to one of the stopper receiving portions 32, 132, the load direction from one side in the left-right direction Y to the other side is referred to as a left pushing direction, and the stopper is applied to the other stopper receiving portions 32, 132. Regarding the force, the load direction from the other side in the left-right direction Y to the one side is referred to as a right pushing direction.

  In this test, the absolute value of the pulling force in the pulling direction or the pushing direction, the absolute value of the damper force in the pulling direction or the pushing direction, and the absolute value of the stopper force in the left pushing direction or the right pushing direction are set to predetermined values, respectively. did. 6 to 8 are diagrams showing the results of analyzing the distribution of Von-Mises stress generated in the center pin 10 according to the embodiment under the above conditions.

  FIG. 6 shows the stress distribution of the center pin 10 when the pulling force F1 in the pulling direction is applied to the lower end 10a of the center pin 10. FIG. 7 shows the stress distribution of the center pin 10 when the left-right motion damper force F2 in the pushing direction is applied to the damper receiving portion 33. FIG. 8 shows the stress distribution of the center pin 10 when the right and left movement stopper force F3 is applied to the other stopper receiving portion 32. In each figure, the absolute value of the stress generated at each position of the center pin 10 is represented by a gray scale. The darker the gray scale color, the larger the absolute value of the stress, and the darker the gray scale color, the greater the stress. This indicates that the absolute value is small. 6 to 8, each of the portions P1 to P8 of the center pin 10 is a portion where the absolute value of the stress is calculated to be relatively large. As shown in FIGS. 6 to 8, it can be confirmed that the stress applied to each of the portions P1 to P8 of the center pin 10 is not extremely higher than the stress applied to the other portions.

  FIG. 9 is a stress limit diagram showing the analysis results of this test. FIG. 9 shows a relationship between the average stress and the fluctuating stress applied to each of the portions P1 to P8 of the center pin 10 and the fatigue limit in each of the portions P1 to P8. In FIG. 9, the horizontal axis represents the average stress (MPa), and the vertical axis represents the fluctuating stress (MPa). Each of the average stress and the fluctuating stress is obtained by synthesizing the stress due to each load of the traction force, the left / right motion damper force, and the left / right motion stopper force. In FIG. 9, each plot D1 to D8 corresponds to each of the portions P1 to P8, and the graph G11 indicates the yield limit (allowable stress) of the material of the center pin 10. In FIG. 9, each plot D1 to D8 is located in a triangular area connecting three intersections of the intersection between the vertical axis and the graph G11 and the two intersections of the horizontal axis and the graph G11. This indicates that the material does not yield in each of the portions P1 to P8 of the center pin 10.

  Graphs G12 to G14 show the fatigue limit of the material of the center pin 10. If each of the plots D1 to D8 is at a position equal to or less than the fatigue limit, it can be determined that the center pin 10 does not cause fatigue failure. This fatigue limit varies depending on the difference in the finishing section for the center pin 10. The graph G12 shows the fatigue limit of the portion of the center pin 10 where the finishing section is “base metal”. The part whose finishing section is the “base material” indicates a part other than the welded part W in the center pin 10 and has not been subjected to finish processing, and the part P1 of the center pin 10 according to the present embodiment. P2, P7, and P8. The graph G14 shows the fatigue limit of the portion of the center pin 10 where the finishing section is “non-welding”. The part whose finishing section is “non-finished” indicates a part which is the welded part W of the center pin 10 and is not finished, and the parts P3, P4 and P4 of the center pin 10 according to the present embodiment. It corresponds to P5 and P6.

  Therefore, in FIG. 9, the graph G12 corresponds to each plot D1, D2, D7, D8 indicated by a circle, and the graph G14 corresponds to each plot D3, D4, D5, D6 indicated by a square. In addition, the graph G13 shows the fatigue limit of the portion of the center pin 10 where the finishing category is “welding G finishing”. The part whose finish section is “weld G finish” is a part which is the welded part W of the center pin 10 and has been finished by the grinder. However, since there is no portion corresponding to “welding G finish” in each of the portions P1 to P8 of the center pin 10 according to the present embodiment, a plot corresponding to “welding non-finishing” is not shown.

  In FIG. 9, the ratio of the distance from the plot to the origin with respect to the distance from the intersection of the straight line connecting the origin and any plot to the fatigue limit line corresponding to the plot (any of graphs G12 to G14). Is shown as a ratio of the average stress and the fluctuating stress to the fatigue limit. That is, the farther the plot is from the fatigue limit line corresponding to the plot, the smaller the ratio of the average stress and the fluctuating stress to the fatigue limit. A small ratio means that the average stress and the fluctuating stress have a margin with respect to the fatigue limit line.

  As shown in FIG. 9, it can be seen that the plots D1, D2, D7, and D8 are lower than the graph G12 and are far away from the graph G12. Similarly, it can be seen that each of the plots D3, D4, D5, and D6 is lower than the graph G14 and is far away from the graph G14. Each plot D1, D2, D7, D8 is located near the center of the distance from the origin to the graph G12, and the ratio of the average stress and the fluctuating stress to the fatigue limit is about half. Thus, according to the center pin 10 according to the example, it can be confirmed that the average stress and the fluctuating stress have a sufficient margin with respect to the fatigue limit.

  On the other hand, FIG. 10 is a stress limit diagram showing an analysis result of the center pin 100 according to the comparative example, and corresponds to the stress limit diagram shown in FIG. Each of the portions PP1 to PP8 of the center pin 100 is a portion where the absolute value of the stress at the center pin 100 is calculated to be relatively large in FIGS. 5A and 5B described above. In FIG. 10, each plot DD1 to DD8 corresponds to each part PP1 to PP8. Each part PP1 to PP4 of the center pin 100 corresponds to a part whose finishing section is “welding G finish”, and each part PP5 to PP8 corresponds to a part whose finishing section is “non-welding”. In FIG. 10, plots DD1 to DD4 indicated by squares correspond to graph G13, and plots DD5 to DD8 indicated by triangles correspond to graph G14.

  As shown in FIG. 10, all plots DD1 to DD4 are located very close to the graph G13, and it can be seen that the ratio of the average stress and the fluctuating stress to the fatigue limit is extremely large. This means that, for each of the plots DD1 to DD4, the ratio of the average stress and the fluctuating stress to the fatigue limit is close to 100%, and there is almost no margin up to the fatigue limit. The plots DD5 to DD8 are located closer to the graph G14 than the plots D3, D4, D5, and D6 shown in FIG. 9, and the ratios of the average stress and the fluctuating stress to the fatigue limit are large. I understand. In the center pin 100 according to the comparative example, the ratio in the portion PP3 (plot DD3) takes the maximum value, and this maximum value is close to 100%. On the other hand, in the center pin 10 according to the example, the ratio in the portion P4 (plot D4) has the maximum value, and this maximum value is equal to the maximum value of the ratio in the portion PP3 of the center pin 100 in the comparative example. In comparison, the value was about 15% lower.

  As described above, in the center pin 100 according to the comparative example, the average stress and the fluctuating stress in each of the portions PP1 to PP8 hardly have a margin up to the fatigue limit, whereas in the center pin 10 according to the present embodiment, each portion P1 It has been found that the average stress and the fluctuating stress of P8 have sufficient margin to the fatigue limit. Therefore, from the analysis results of this test, it was confirmed that according to the center pin 10 according to the present embodiment, the average stress and the fluctuating stress applied to the center pin 10 can be reduced, and a more robust structure can be obtained.

  The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the stopper receiving portions 32 are provided on both sides of the main body portion 30 in the left-right direction Y. However, the stopper receiving portion 32 may be provided on only one side of the main body 30 in the left-right direction Y. In the embodiment described above, the damper receiving portion 33 is formed integrally with one stopper receiving portion 32. However, the damper receiving portion 33 may be configured separately from the one stopper receiving portion 32. Further, in the above-described embodiment, the main body 30 may not have the enlarged diameter portion 30b, and the flange 31 may not be provided with the concave portion 31c.

  DESCRIPTION OF SYMBOLS 1 ... Bogie for railway vehicles, 2 ... Bogie frame, 3 ... Wheel, 4 ... Axle, 5 ... Wheel axle, 6 ... Bearing, 7 ... Shaft box, 8 ... Shaft spring, 9 ... Air spring, 10 ... Center pin, 10a ... Lower end, 11 side beams, 12 cross beams, 13 traction device, 14 traction link, 18 stopper, 19 damper, 30 body portion, 30a constant diameter portion, 30b enlarged diameter portion, 30c lower end , 30d: upper end, 30e: outer surface, 31: flange, 31a: insertion hole, 31b: peripheral, 31c: concave, 32: stopper receiving part, 32a: upper end, 33: damper receiving part, 40: Fastening bolt.

Claims (6)

A railway vehicle center pin that connects a vehicle body of a railway vehicle and a bogie frame disposed below the vehicle body,
A cylindrical main body,
A flange portion protruding from an outer surface of the main body at one end of the main body,
A stopper receiving portion coupled to the outer side surface of the main body portion and receiving a stopper for restricting displacement of the main body portion;
A damper receiving portion coupled to the outer side surface of the main body portion and receiving a damper for reducing vibration of the main body portion,
The main body and the flange are an integral forged body,
Both the stopper receiving portion and the damper receiving portion are forged bodies,
The center pin for a railway vehicle, wherein the stopper receiving portion is welded to the outer surface of the main body. The stopper receiving portion and the damper receiving portion are an integral forged body,
The center pin for a railway vehicle according to claim 1, wherein the damper receiving portion is coupled to the outer side surface of the main body portion via the stopper receiving portion. The flange portion is provided with a plurality of insertion holes for inserting a fastening member used for coupling with the vehicle body,
The center pin for a railway vehicle according to claim 1, wherein a concave portion that is depressed toward a center side of the flange portion is provided at a position between the insertion holes at a peripheral portion of the flange portion. . A center pin for a railway vehicle according to any one of claims 1 to 3,
A traction device having a traction link connecting the bogie frame and the other end of the main body,
The stopper arranged so as to face the stopper receiving portion,
The damper arranged to face the damper receiving portion;
A bogie for a railway vehicle, comprising: A method of manufacturing a center pin for a railway vehicle that connects a vehicle body of a railway vehicle and a bogie frame disposed below the vehicle body,
A cylindrical main body, and a flange portion protruding from an outer surface of the main body at one end of the main body are integrally formed by forging,
A stopper receiving portion that receives a stopper that regulates the displacement of the main body portion and a damper receiving portion that receives a damper that reduces vibration of the main body portion are formed by forging, respectively.
A method for manufacturing a center pin for a railway vehicle, wherein the stopper receiving portion is welded to the outer surface of the main body by welding. The stopper receiving portion and the damper receiving portion are integrally formed by forging,
The method according to claim 5, wherein the damper receiving portion is coupled to the outer surface of the main body via the stopper receiving portion.