EP1138569A2

EP1138569A2 - Variable-wheel-gage bogie for rolling stock

Info

Publication number: EP1138569A2
Application number: EP01107692A
Authority: EP
Inventors: Isao Railway Tech. Research Institute Okamoto; Noriaki Railway Tech. Research Institute Tokuda; Tomohiro Railway Tech. Res. Institute Toyooka; Kensaku Matsuoka; Kunimasa Okimatsu; Tomohiro Ito; Yukio Minowa
Original assignee: Nippon Sharyo Ltd; Railway Technical Research Institute; Fuji Jukogyo KK; Fuji Heavy Industries Ltd; Japan Railway Construction
Current assignee: Nippon Sharyo Ltd; Railway Technical Research Institute; Subaru Corp; Japan Railway Construction
Priority date: 2000-03-28
Filing date: 2001-03-28
Publication date: 2001-10-04
Also published as: JP2001270439A; AU781868B2; AU3132901A; JP3652577B2; EP1138569A3

Abstract

A variable-wheel-gage bogie has axles (24), journal box beams (29) bearing the body weight of a wheeled vehicle, journal boxes (50) axially slidably fitted in the journal box beams (29), respectively, axle sleeves (30) put on each axle (24) and supported in journal bearings (51) on the journal boxes (50), respectively, wheels (36) fixedly joined to the axle sleeves (30), respectively, and locking mechanisms (60) for locking the wheels (36) so as to be axially immovable. The locking mechanisms (60) are disengaged by unlocking rails (73) extended along body support rails (70) that bear the body weight of a wheeled vehicle and are engaged by locking rails (74) extended along the body support rails (70). The locking mechanisms (60) can be operated in a state here the journal box beams (29) are supported on the body support rails (70) and the axle (24) is not loaded. Thus, the locking mechanisms (60) can be surely engaged to lock the wheels (36) so as to be axially immovable and can be surely disengaged to permit the axial movement of the wheels (36) for wheel-back-gage change.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a variable-wheel-gage bogie capable of continuously varying its wheel-back-gage to run continuously on railroad tracks respectively of different railroad gages, such as the railroad tracks of the Shinkansen railroad and the railroad tracks of the conventional Japanese railroads. More specifically, the present invention relates to an improved variable-wheel-gage bogie for rolling stock, having a locking mechanism for locking a wheel supporting mechanism in place so that a wheel supported thereon cannot be axially moved for wheel-back-gage change, capable of being surely engaged and disengaged.

Japanese railroad tracks include a standard-gage track of a railroad gage of 1435 mm, which is used for the Shinkansen railroads, and a narrow-gage track of a railroad gage of 1067 mm, which is used for the conventional railroads. Development of rolling stock capable of continuously running on the railroad tracks respectively having the different railroad gages will provide very important advantageous effects on the convenience of passengers, and the reduction of time necessary for traveling to destinations and railroad construction costs. The applicant of the present invention patent application developed various variable-wheel-gage bogies for rolling stock and filed applications for patent previously.

Known variable-wheel-gage bogies will be described by way of example. A variable-wheel-gage bogie shown in Fig. 16 has a plurality of wheels 4 and associated mechanisms. Only one of the wheels 4 and the associated mechanism will be described because all the wheels 4 and the associated mechanisms are the same. An axle 2 is supported for vertical movement relative to a journal box beam 1 and a axle sleeve 3 is put on the axle 2 so as to be axially slidable. The wheel 4 is supported for rotation on bearings, not shown, put on the axle sleeve 3. A locking block 5 is fixed to one end part of the axle sleeve 3. The locking block 5 is provided on its upper surface with a pair of locking projections 6 and 7 spaced a predetermined distance apart from each other in the direction of the axis of the axle 2. The journal box beam 1 is provided with a locking opening 8 in which the locking projection 6 or 7 engages and an escape opening 9.

When the outer locking projection 6, i.e., the locking projection on the left side as viewed in Fig. 16, is engaged in the locking opening 8, the locking block 5 and the axle sleeve 3 supporting the wheel 4 and fixed to the locking block 5 are locked at a position for the narrow-gage track.

When the inner locking projection 7, i.e., the locking projection on the right side as viewed in Fig. 16, is engaged in the locking opening 8, the axle sleeve 3 supporting the wheel 4 is locked at a position for the standard-gage track.

When moving each of the wheels 4 of the variable-wheel-gage bogie thus formed from the position for the narrow-gage track to the position for the standard-gage track, a sled 10 supported on a lower end part of the journal box beam 1 is set on support rollers 12 supported on a body support rail 11 horizontally extended on the ground G to support the journal box beam 1 supporting a car body.

Then, a wheel 4 included in a railroad vehicle supported on the variable-wheel-gage bogie rolls on a downward slope section of a rail 13. Consequently, the wheel 4 moves gradually downward relative to the horizontal body support rail 11, the axle 2 descends relative to the journal box beam 1 and the locking projection 6 is disengaged from the locking opening 8, so that the axle sleeve 3 is able to move along the axle 2. Then, the axle sleeve 3 is moved outward, i.e., to the left as viewed in Fig. 16, to set the wheel 4 at the position for the standard-gage track.

Then, the wheel 4 rolls on an upward slope section of the rail 13. Consequently, the axle 2 rises gradually relative to the journal box beam 1 and the inner locking projection 7 engages in the locking opening 8. Thus, axle sleeve 3 supporting the wheel 4 is locked at the position for the standard-gage track.

The axle 2 must move vertically relative to the journal box beam 1 when changing the positions of the wheels 4 of this variable-wheel-gage bogie and hence the journal box beam 1 inevitably has a big vertical dimension.

The wheel-back-gage of a variable-wheel-gage bogie shown in Fig. 17 can be changed without vertically moving an axle 2 relative to a journal box beam 1

Referring to Fig. 17, an axle sleeve 3 is axially slidably put on the axle 2. A locking block 5 is put on the axle sleeve 3 for movement together with the axle sleeve 3. The locking block 5 is fitted axially slidably in a cylindrical bore la formed in the journal box beam 1. A locking lever 15 is supported for turning by a shaft 14 on the journal box beam 1 and is biased counterclockwise by a compression coil spring 16. Normally, the locking lever 15 is in engagement with a locking projection 5a projecting from a lower end part of a locking block 5. Thus the locking block 5 is connected to the journal box beam 1 by the locking lever 15, the axle sleeve 3 is unable to move axially on the axle 2 and hence the wheel 4 is locked to inhibit the change of the wheel-back-gage.

When a sled 10 rides support rollers 12 supported on a body support rail to change the wheel-back-gage, the sled 10 is turned to a horizontal position as shown in Fig. 17 and, at the same time, a link 17 turns the locking lever 15 clockwise on the shaft 14 to disengage the locking lever 15 from the locking projection 5a. Consequently, the axle sleeve 3 can move axially on the axle 2 for wheel-back-gage change.

In the variable-wheel-gage bogie shown in Fig. 17, the locking lever 15 starts turning in an unlocking direction, i.e., a clockwise direction as viewed in Fig. 17, simultaneously with the start of turning of the sled 10 toward the horizontal position upon the engagement of the sled 10 with the first one of the support rollers 12 supported on the body support rail. Similarly, the locking lever 15 starts turning in a locking direction, i.e., a counterclockwise direction as viewed in Fig. 17, simultaneously with the start of the sled 10 leaving the last one of the support rollers 12. However, it is possible that an unlocking operation for unlocking the axle sleeve 3 supporting the wheel 4 cannot be smoothly performed because the axle 2 is loaded with the body weight of a wheeled vehicle and the locking block 5 is unable to slide axially on the axle 2, and the locking lever 15 must turn in the unlocking direction even when the locking projection 5a of the locking block 5 is pressed firmly and axially against the locking lever 15. Similarly, it is possible that a locking operation for locking the axle sleeve 3 supporting the wheel 4 at a desired position cannot be smoothly performed because the axle 2 is loaded with the body weight and the locking block 5 is unable to slide axially on the axle 2, and the locking lever 15 must turn in the locking direction even when the locking projection 5a of the locking block 5 is dislocated relative to the locking lever 15 with respect to an axial direction.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide an improved variable-wheel-gage bogie provided with a journal box having a small vertical dimension and capable of surely locking and unlocking a locking mechanism for locking a support device supporting a wheel so that wheel-back-gage will not change.

According to one aspect of the present invention, a variable-wheel-gage bogie for rolling stock comprises: axles; a drive motor mounted on a truck frame; a reduction gear for transmitting output rotative driving force of the drive motor to the axle and reducing an input speed to a lower output speed; right and left journal box beams connected to the truck frame and to right and left axle end beams supported on thrust bearings mounted on opposite ends of the axle, respectively; right and left journal boxes fitted in the right and the left journal box beam, respectively, so as to be slidable along an axis of the axle relative to the journal box beams, respectively; right and left axle sleeves supported in axle bearings on the pair of journal boxes, respectively, and put on the axle; right and left wheels mounted on the right and the left axle sleeve for rotation together with the right and the left axle sleeve, respectively; a rotative driving force transmitting means interlocking each axle sleeve and the axle to transmit rotative driving force from the axle to the axle sleeve; and locking mechanisms each having a locking member that can move between a locking position to lock the journal box at either of a position where the wheel is set at a position for a standard-track and a position where the wheel is set at a position for a narrow-track so that the journal box is axially immovable relative to the journal box beam, and an unlocking position to unlock the journal box so that the journal box is axially movable relative to the journal box beam; wherein the locking member is operated by a first operating means disposed along a body support rail on which the journal box beam rides when changing wheel-back-gage so as to be moved to the unlocking position.

In this variable-wheel-gage bogie for rolling stock, the axle does not move vertically in the journal box beam when locking the journal boxes so that the wheel-back-gage cannot be changed. Therefore, the journal box beam has a small vertical dimension.

The locking mechanism that locks the journal box so that the wheel cannot move axially for wheel-back-gage change is not operated by the body weight-bearing rail that engages the journal box beam but the same is disengaged by the first operating means independent of the body support rail. Thus the locking mechanism can be disengaged for an unlocking operation after the journal box has been supported on the body support rail and the body weight has been removed from the axle and therefore the locking mechanism that restrains the wheel from axial movement to inhibit wheel-back-gage change can be surely disengaged.

In the variable-wheel-gage bogie according to the present invention, it is preferable that the locking member is returned to the locking position by a second operating means disposed beside the body support rail when the locking member does not return to the locking position after a wheel-back-gage changing operation has been completed. Since the locking mechanism is operated while the journal box is supported on the body weight-bearing rail and the axle is not loaded with the body weight, the locking mechanism can be surely and smoothly engaged so that the wheel-back-gage cannot be changed.

In the variable-wheel-gage bogie according to the present invention, it is preferable that the rotative driving force transmitting means is a roller spline mechanism comprising the axle sleeve provided with longitudinal grooves in its inner circumference, the axle provided with longitudinal grooves in its circumference, and a plurality of rollers slidably placed in the grooves to transmit rotative driving force from the axle to the axle sleeve. Thus, the rolling spline mechanism is loaded with only the rotative driving force and any external radial force is not exerted thereon. Therefore, the function of the roller spline mechanism is not deteriorated by abrasion.

In the variable-wheel-gage bogie according to the present invention, it is preferable that the axle is covered for protection with cylindrical dust covers and an outer end part of each dust cover on the side of the wheel is supported on an annular support member supported by a bearing on the wheel. Thus, a part of the axle close to the wheel can be surely covered for protection and the outer end part of the dust cover on the side of the wheel can be supported with reliability.

In the variable-wheel-gage bogie according to the present invention, it is preferable that an inner end part of each dust cover on the side of the drive motor is supported on a cylindrical support member through which the axle is extended and fastened to the drive motor. Thus, a part of the axle close to the drive motor can be surely covered for protection and the inner end part of the dust cover on the side of the drive motor can be supported with reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the following description taken in connection with the accompanying drawings, in which:

Fig. 1 is a horizontal, longitudinal sectional view of an essential part of a variable-wheel-gage bogie in a preferred embodiment according to the present invention for rolling stock, in a state for a standard-track;

Fig. 2 is a horizontal, longitudinal sectional view of an essential part of the variable-wheel-gage bogie shown in Fig. 1 in a state for a narrow-track;

Fig. 3 is an enlarged, horizontal, longitudinal sectional view of a journal box beam and associated parts included in the variable-wheel-gage bogie shown in Fig. 1;

Fig. 4 is an enlarged, horizontal, longitudinal sectional view of the journal box beam and the associated parts in the variable-wheel-gage bogie shown in Fig. 2;

Fig. 5 is a sectional view of a roller spline mechanism;

Fig. 6 is an enlarged sectional view of an essential part of the roller spline mechanism shown in Fig. 5;

Fig. 7 is an enlarged half sectional view of a dust cover shown in Fig. 1;

Fig. 8 an enlarged longitudinal sectional view of a journal box beam included in the variable-wheel-gage bogie shown in Fig. 1;

Fig. 9 is a side elevation of the journal box beam shown in Fig. 8;

Fig. 10 is a partly cutaway front elevation of the journal box beam shown in Fig. 9;

Fig. 11 is a perspective view of a locking mechanism;

Fig. 12 is a perspective view of the locking mechanism shown in Fig. 11;

Figs. 13(a) and 13(b) are sectional views of assistance in explaining the operation of the locking mechanism;

Figs. 14(a) and 14(b) are sectional views of assistance in explaining the operation of the locking mechanism;

Fig. 15 is a typical view of assistance in explaining the functions of an unlocking rail and a locking rail;

Fig. 16 is a sectional view of a conventional variable-wheel-gage bogie for rolling stock; and

Fig. 17 is a sectional view of another conventional variable-wheel-gage bogie for rolling stock.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A variable-wheel-gage bogie in a preferred embodiment according to the present invention for rolling stock will be described with reference to Figs. 1 to 15, in which directions perpendicular to the ground are referred to as vertical directions, directions parallel to a direction in which a wheeled vehicle moves are referred to as forward and backward directions, and directions parallel to the axis of an axle are referred to as axial directions.

Referring to Figs. 1 to 4, the output rotative driving force of a drive motor 21 mounted on a truck frame is transmitted through flexible coupling 22 and a reduction gear 23 suspended from the truck frame to an axle 24 to drive the axle 24 for rotation. A pair of axle end beams 27 is mounted on thrust bearings 26 held in place on opposite end parts of the axle 24 by nuts 25, respectively.

Support arms

29a and 29b of a pair of journal box beams 29 are connected to the pair of axle end beams 27 by pins, respectively. Thus, the pair of journal box beams 29 are spaced a predetermined axial distance apart and the axle 24 is able to rotate relative to the pair of journal box beams 29.

Stepped axle sleeves 30 are put on the axle 24 so as to be axially slidable on the axle 24. A tubular slide bearing 31 of a material having antifriction characteristics and having a small wall thickness is fitted in each axle sleeve 30, so that the axle sleeve 30 is able to slide smoothly on a large-diameter part 24a of the axle 24.

An inner splined tube 33 included in a roller spline mechanism 32 is put on a small-diameter part 24b of the axle 24 on the side of the end of the axle 24. The outer circumference 33a (Fig. 5) of the inner splined tube 33 is flush with the circumference of the large-diameter part 24a of the axle 24. Thus the axle sleeve 30 internally provided with the slide bearing 31 is able to slide axially also along the outer circumference 33a of the inner splined tube 33.

An external radial force exerted on the axle sleeve 30 is transmitted directly to the large-diameter part 24a of the axle 24 and is transmitted indirectly through the inner splined tube 33 to the small-diameter part 24b of the same.

Referring to Figs. 5 and 6, the outer circumference 33a of the inner splined tube 33 is provided with a plurality of axial grooves 33b formed in the entire length of the inner splined tube 33 at equal angular intervals. An outer end part of the inner circumference of the axle sleeve 30 is provided with axial grooves 30a so as to correspond to the grooves 33a of the inner splined tube 33, respectively.

A plurality of rollers 34 are fitted in spaces defined by the

corresponding grooves

30a and 33a, respectively. The rollers 34 are retained by retainers 35 attached to the axle sleeve 30 and slides in the grooves 33a of the inner splined tube 33 together with the axle sleeve 30 only when the axle sleeve 30 is moved for wheel-back-gage change. Since a very low rotative driving force is exerted on the axle 24 during wheel-back-gage change, an operation for wheel-back-gage change is not affected by the resistance of the rollers 34 against axial sliding.

The diameter of the rollers 34 is slightly smaller than the size corresponding to the diameter of the rollers 34 of the spaces defined by the

grooves

30a and 33a. When a rotative driving force is applied to the axle 24, the rollers 34 touches only contact

points

30b and 33b of the

grooves

30a and 33a to transmit the rotative driving force from the axle 24 to the axle sleeve 30. Radial force exerted on the axle sleeve 30 is not transmitted to the axle 24 by the rollers 34.

A wheel 36 is put on an inner end part, i.e., an end part on the side of the middle of the axle 24, of the axle sleeve 30. The wheel 36 rotates together with the axle sleeve 30 and the axle 24 and moves axially together with the axle sleeve 30 on the axle 24 for wheel-back-gage change.

As shown in Figs. 1 and 2, the pair of large-diameter parts 24a of the axle 24 are covered with a pair of

dust covers

40R and 40L having the shape of a cylindrical bellows, respectively. Outer end parts of the

dust covers

40R and 40L on the side of the wheels 36 are supported on ball bearings 43 put on dust cover support bosses 36a projecting from inner side surfaces of the wheels 36, respectively. Thus the

dust covers

40R and 40L are supported securely on the wheels 36.

As shown in Fig. 7, an inner end part of the left dust cover 40L on the side of the drive motor 21 is supported on a cover 41. The cover 41 has a cylindrical body 41a, a left flange 41c formed at the left end of the body 41a, a right flange 41d formed at the right end of the body 41a, and a bracket 41b fastened to the drive motor 21 with bolts 42. The inside diameter of the body 41a of the cover 41 is determined so that the displacement of the drive motor 21 and the axle 24 relative to each other can be absorbed by the gap between the axle 24 and the body 41a of the cover 41. Therefore the axle 24 does not come into contact with the body 41a of the cover 41 when the axle 24 is displaced relative to the drive motor 21.

The variable-wheel-gage bogie in this embodiment changes the wheel-back-gage without greatly raising or lowering the axle 24 relative to the journal box beams 29. Therefore, the displacement of the axle 24 relative to the drive motor 21 is small and hence the outside diameter of the body 41a of the cover 41 may be small.

The inner end of the dust cover 40L is fastened to the left flange 41c of the cover 41. An inner end part of the right dust cover 40R on the side of the reduction gear 23 is fastened directly to the case of the reduction gear 23. Thus, the

dust covers

40R and 40L are extended when the wheels 36 are set at positions for the standard-track as shown in Fig. 1, and are contracted when the wheels 36 are set at positions for the narrow-track as shown in Fig. 2.

As shown in Fig. 7, a part of the axle 24 between the drive motor 21 and the reduction gear 23 is covered with a middle dust cover 45 having the shape of a cylindrical bellows. The middle dust cover has a left end fastened to the right flange 41d of the cover 41, and a right end fastened to a ring 46 formed on the reduction gear 23. The middle dust cover 45 covers and protects the part of the axle 24 between the drive motor 21 and the reduction gear 23 and is able to flex according to the displacement of the reduction gear 23 relative to the drive motor 21.

Referring to Figs. 3 and 4, a journal box 50 is fitted in the journal box beam 29 so as to be axially slidable at least between a standard-track position and a narrow-track position. A journal bearing 51 is interposed between the journal box 50 and the axle sleeve 30 to enable the axle sleeve 30 to rotate relative to the journal box 50. The axial position of the journal bearing 51 relative to the journal box 50 and the axle sleeve 30 is determined by

spacers

52, 53 and 54. Thus the journal box 50 moves axially together with the axle sleeve 30. A dust cover 56 having the shape of a cylindrical bellows is extended between a cover 55 closing an open end of the journal box 50 and the axle end beam 27 to cover an end part of the axle 24.

Referring to Figs. 8 and 9, a sled 10 is supported on a lower end part 29c of the journal box beam 29. The sled 10 slides on a plurality of support rollers 12 placed on a body support rail 70 to support the journal box beam 29 bearing up the body weight of a wheeled vehicle, not shown, so that the axle 24 is unloaded during wheel-back-gage change.

As shown in Fig. 4, a locking block 57 substantially resembling a rectangular parallelepiped is fastened to one end of the journal box 50 with bolts 57a. As shown in Fig. 10, the locking block 57 is fitted in an axial groove 29e formed in and end part 29d of the journal box beam 29. The locking block 57 slides axially in the journal box 29 together with the journal box 50. The locking block 57 is provided with a pair of

vertical grooves

57b and 57c. The center distance between the

grooves

57b and 57c is equal to a distance for which the wheel 36 is moved for wheel-back-gage change.

Referring to Figs. 9 and 10, a locking mechanism 60 for locking the locking block 57 so that the locking block 57 is unable to move axially relative to the journal box beam 29 is mounted on the end part 29d of the journal box beam 29. As shown in Figs. 9 to 12, the locking mechanism 60 has a locking member 61 that can be slidably inserted in a vertical through hole 29f of an elliptic cross section formed in the end part 29d of the journal box beam 29. The locking member 61 has an upper head part 61a of an elliptic cross section and a round stem part 61b extending downward from the head part 61a.

As shown in Figs. 9 and 10, a compression coil spring 62 is extended between the lower end of the round stem part 61b of the locking member 61 and the lower surface of the end part 29d to bias the locking member 61 downward.

A support shaft 63 is extended in parallel to the axis of the axle 24 and is supported for turning on the lower end part 29c of the journal box beam 29. A support arm 64 has a base end part fixed to a middle part of the support shaft 63 and a free end part joined to the lower end of the round stem part 61b of the locking member 61. The locking member 61 can be vertically moved by turning the support shaft 63.

As shown in Fig. 13(a), the base end part of the support arm 64 is provided with a projection 64a that comes into contact with a lower side surface 29g of the journal box beam 29 to limit the downward movement of the locking member 61 beyond a predetermined locking position.

Referring to Figs. 10 and 11, an unlocking arm 65 has a base end part fixed to an outer end part of the support shaft 63 so that the unlocking arm 65 extends in a direction in which the locking arm 64 extends and a free end part supporting an unlocking roller 66. When the unlocking roller is raised, the unlocking arm 65 turns the support shaft 63, so that the locking member 61 is moved upward by the support arm 64.

Referring to Figs. 10 and 12, a locking arm 67 has a base end part fixed to an inner end part of the support shaft 63 on the side of the wheel 36 so that the locking arm 67 extends in a direction opposite that in which the support arm 64 extends and a free end part supporting a locking roller 68. When the locking roller 68 is raised, the locking arm 67 turns the support shaft 63, so that the locking member 61 is moved downward by the support arm 64.

As shown in Figs. 8 and 9, the plurality of support rollers 12 are supported for ration on the body weight-bearing rail 70. When changing the wheel-back-gage, the sled 10 supported on the lower end part of the journal box beam 29 rides the support rollers 12 to bear up the body weight of the wheeled vehicle.

As shown in Fig. 8, an outer guide part 71 is formed in an outer side part of the body support rail 70 to guide the journal box beam 29 during wheel-back-gage change. The guide part 71 is provided with a plurality of guide rollers 72 supported for rotation about a vertical axis. The guide rollers 72 come into contact with the side surface of the journal box beam 29 to guide the journal box beam 29.

As shown in Figs. 8 and 9, an unlocking rail 73 (first operating means) having

cam surfaces

73a and 73b is extended on the upper end of the guide part 71. The unlocking roller 66 rolls along the cam surfaces 73a and 73b. Similarly, a locking rail 74 (second operating means) having a cam surface 74a is extended on the upper end of an inner guide part formed in an inner side part of the body weight-bearing rail 70. The locking roller 68 rolls along the cam surface 74a.

An operation of the locking mechanism 60 to be carried out when changing the wheel-back-gage for the standard-track to that for the narrow-track will be described with reference to Figs. 10 to 15. The arrows shown in Figs. 13 to 15 indicate the direction of forward travel of the wheeled vehicle.

Referring to Figs. 9 to 2, the locking member 61 is biased and held at the predetermined locking position by the compression coil spring 62 in the normal state as shown in Fig. 13(a), in which the head part 61a of the locking member 61 extends in both the through hole 29f of the journal box beam 29 and the inner groove 57b of the locking block 57. Thus, the journal box 50 united with the locking block 57 is locked so that the journal box 50 is unable to move axially relative to the journal box beam 29.

In this state, the predetermined distance between the right and the left journal box beams 29 is maintained by the axle 24. Consequently, the right and the left wheel 36 mounted on the axle sleeves 30 supported on the journal boxes 50 are held axially immovable at a predetermined wheel-back-gage.

When the railroad gage changes from the standard railroad gage to the narrow railroad gage, the locking member 61 must be raised against the resilience of the compression coil spring 62 to move the head part 61a upward out of the groove 57b of the locking block 57 as shown in Fig. 13(b). The unlocking rail 73 extended along the body weight-bearing rail 70 is used to raise the locking member 61. As shown in Figs. 9 and 15, the unlocking rail 73 has the pair of inclined cam surfaces 73a formed symmetrically in the opposite end parts of the unlocking rail 73, and the horizontal cam surface 73b extending between the pair of inclined cam surfaces 73a.

As the wheeled vehicle running on the track rails 13 approaches a railroad gage changing section, the track rails 13 slope down forward gradually. Then, the sled 10 supported on the lower end parts of the right and the left journal box beam 29 start sliding on the support rollers 12. Consequently, the body weight of the wheeled vehicle is born by the body support rails 70.

In this state, the body weight is removed from the axle 24 and hence the right and the left journal box 50 are able to slide easily in the right and the left journal box beams 29, respectively. Meanwhile, the unlocking roller 66 of each locking mechanism 60 advances from a position shown in Fig. 15(a) and engages the inclined cam surface 73a sloping up forward.

As the wheeled vehicle advances further in the direction of the arrow shown in Fig. 15, the unlocking roller 66 is moved gradually upward by the inclined cam surface 73a as shown in Fig. 15(b). Consequently, the unlocking arm 65 is turned to turn the support shaft 63 counterclockwise as viewed in Fig. 15 and thereby the support arm 64 is turned to raise the locking member 61 against the resilience of the compression coil spring 62.

As the wheeled vehicle advances further, the unlocking roller 66 rolls along the horizontal cam surface 73b of the unlocking rail 73 as shown in Fig. 15(c). Then, as shown in Fig. 13(b), the head part 61a of the locking member 61 is held at a position above and outside the groove 57b f the locking block 57. Consequently, the journal boxes 50 united with the locking blocks 57 are released from the corresponding journal box beams 29 to set a wheel-back-gage changing condition.

After the wheel-back-gage changing condition has been set, the space between the track rail 13 and the associated body support rail 70 changes. When changing the wheel-back-gage from that for the standard railroad gage to that for the narrow railroad gage, the track rails 13 deviate gradually from the associated body support rails 70 so that the distance between the track rails 13 decreases gradually and wheel guide rails 18 extended along the track rails 13 come into contact with the wheels 36 to push the wheels 36 toward each other.

Consequently, the wheels 36, the axle sleeves 30 and the journal boxes 51 are moved axially inward. At the same time, the locking blocks 57 slides in the grooves 29e of the journal box beams 29, respectively. Upon the arrival of the wheels 36 at the positions for the narrow railroad gage, the outer grooves 57c of the locking blocks 57 are aligned with the through holes 29f of the journal box beams 29, respectively.

As the wheeled vehicle advances further, the unlocking rollers 66 start rolling down along the inclined cam surfaces 73a sloping down forward of the unlocking rails 73. Then, the locking members 61 are lowered gradually by the resilience of the compression coil springs 62 and, finally, the head parts 61 of the locking members 61 engages in the grooves 57c of the locking blocks 57. Thus, the journal boxes 50 united with the locking-blocks 57 are locked in place on the journal box beams 29, so that the wheels 36 are held axially immovable at the positions for the narrow railroad gage.

If the locking member 61 is unable to move smoothly relative to the journal box beam 29 or the locking block 57, the locking member 61 cannot be lowered by the resilience of the compression coil spring 62 as shown in Fig. 14(a) and the wheels 36 cannot be locked so as to be axially immovable. To avoid such a trouble, the locking member 61 is lowered forcibly by the locking rail 74 extended along the body weight-bearing rail 70. As shown in Fig. 15, the locking rail 74 is disposed near a part of the unlocking rail 73 provided with the inclined cam surface 73a. The locking rail 74 has an inclined cam surface 74a gradually sloping up forward, i.e., in the direction of forward travel of the wheeled vehicle indicated by the arrow in Fig. 15.

The locking roller 68 of the locking mechanism 60 remain at its low position as shown in Figs. 14(a) and 15(d) when the locking member 61 cannot be lowered by the resilience of the compression coil spring 62 after the completion of wheel-back-gage change. As the wheeled vehicle advances further with the locking roller 68 remaining at its low position, the locking roller 68 engages and is raised forcibly by the inclined cam surface 74a of the locking rail 74.

Consequently, the locking arm 67 turns the support shaft 63 counterclockwise as viewed in Fig. 14(b) together with the support arm 64 and thereby the locking member 61 is lowered forcibly. Finally, the head part 61a of the locking member 61 engages in the groove 57c of the locking block 57, the journal box 50 united with the locking block 57 is locked in place on the journal box beam 29, so that the wheels 36 are held axially immovable.

Although the variable-wheel-gage bogie in the preferred embodiment has been described, the present invention is not limited thereto in its practical application and various changes may be made in the embodiment specifically described herein.

For example, the support arm 64, the unlocking arm 65 and the locking arm 67 may be connected by cushioning mechanisms each including, for example, a torsion spring to the support shaft 63 instead of directly fastening the same to the support shaft 63 to prevent the breakage of the support shaft 63 due to overloading.

The edges of the lower end of the head part 61a of the locking member 61 and the edges of the surfaces defining the

grooves

57b and 57 of each locking block 57 may be chamfered for the further smooth engagement of the locking member 61 with and disengagement of the same from the locking block 57.

When a slight gap is formed between the wheel guide rail 18 and the wheel 36 to permit the free axial movement of the locking block 57 in a narrow range, the locking member 61 can be further smoothly engaged with and disengaged from the locking block 57.

As apparent from the foregoing description, according to the present invention, the variable-wheel-gage bogie does not move the axle vertically in the journal box beams when locking the wheels so as to be axially immovable and when unlocking the wheels and hence the journal box beam can be formed in a small vertical dimension.

The locking mechanism that locks the wheel so as to be axially immovable is disengaged by the first operating means separate from the body weight-bearing rail and is not operated by the journal box that comes into contact with the body weight-bearing rail. Since the journal box can be unlocked after the journal box beam has been supported on the body support rail and the body weight has been removed from the axle, the locking mechanism can be surely disengaged.

If the locking member cannot be returned to its locking position by the resilience of the compression coil spring after the completion of wheel-back-gage change, the locking member is shifted forcibly to its locking position by the second operating means disposed in parallel to the body support rail. Since the locking mechanism can be operated after the journal box beam has been supported on the body support rail and the body weight has been removed from the axle, the wheels can be smoothly and surely locked so as to be axially immovable.

Claims

A variable-wheel-gage bogie for rolling stock, comprising:

axles (24);

a drive motor (21) mounted on a truck frame;

a reduction gear (23) for transmitting output rotative driving force from the drive motor (21) to the axle (24) and reducing an input speed to a lower output speed;

right and left journal box beams (29) connected to the truck frame and to right and left axle end beams (27) supported on thrust bearings (26) mounted on opposite ends of the axle (24), respectively;

right and left journal boxes (50) fitted in the right and the left journal box beam (29), respectively, so as to be slidable along an axis of the axle (24) relative to the journal box beams (29), respectively;

right and left axle sleeves (30) supported in axle bearings (31) on the pair of journal boxes (50), respectively, and put on the axle (24);

right and left wheels (36) mounted on the right and the left axle sleeve (30) for rotation together with the right and the left axle sleeve (30), respectively;

a rotative drive force transmitting means (32, 33) interlocking each axle sleeve (30) and the axle (24) to transmit rotative driving force from the axle (24) to the axle sleeve (30); and

locking mechanisms (60) each having a locking member (61) that can be moved between a locking position adapted to lock the journal box (50) at either of a position where the wheel (36) is set at a position for a standard-track and a position where the wheel (36) is set at a position for a narrow-track so that the journal box (50) is axially immovable relative to the journal box beam (29), and an unlocking position adapted to unlock the journal box (50) so that the journal box (50) is axially movable relative to the journal box beam (29);

wherein the locking member (61) is operated by first operating means (73) disposed along a body support rail (70) on which the journal box beam (29) rides when changing wheel-back-gage so as to be moved to the unlocking position.
The bogie according to claim 1,
wherein the locking member (61) is adapted to be returned to the locking position by second operating means (74) disposed along the body support rail (70) when the locking member (61) does not return to the locking position after a wheel-back-gage changing operation has been completed.
The bogie according to claim 1 or 2,
wherein the rotative driving force transmitting means (32, 33) comprise a roller spline mechanism (32) comprising the axial sleeve (30) provided with longitudinal grooves (30a) in its inner circumference, the axle (24) provided with longitudinal grooves (33a) in its circumference, and a plurality of rollers (34) slidably placed in the grooves (30a, 33a) to transmit a rotative driving force from the axle (24) to the axle sleeve (30).
The bogie according to anyone of claims 1 to 3,
wherein the axle (24) is covered for protection with cylindrical dust covers (40L, 40R) and an outer end part of each dust cover (40L, 40R) on the side of the wheel (36) is supported on an annular support member (44) supported by a bearing (43) on the wheel (36).
The bogie according to anyone of claims 1 to 4,
wherein an inner end part of each dust cover (40L, 40R) on the side of the drive motor (21) is supported on a cylindrical support member (41) through which the axle (24) is extended and fastened to the drive motor (21).