JP2905114B2 - Rotary joint structure and wheel set for variable gauge bogie - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary shaft for attaching a rotatable member to an outer periphery of the rotary shaft so as to be slidable in the axial direction, and for transmitting a rotational force of the rotary shaft to the rotatable member. The present invention relates to a rotary joint structure. In addition, in a vehicle running on a track having a different gauge (also referred to as a gauge) which is a distance between a pair of rails, a variable gauge bogie in which a gauge (a right and left wheel distance) of a bogie on which the vehicle body is mounted can be changed according to a rail interval. The present invention relates to a wheel set for a variable gauge bogie using the rotary joint structure.

[0002]

2. Description of the Related Art A variable axle bogie of the above type is described in Japanese Patent Application Laid-Open No. Hei 7-52795, which was filed by the present applicant as a patent application. This wheel set 21
5, a drive gear 24 is provided so as to be integrally rotatable, and a fixed wheel 23 is attached to one end of an axle 22 that rotates via the drive gear 24 by rotation of a motor (not shown).
A wheel (driven wheel) 26 is provided on the other end side so as to be slidable in the axial direction, and a bearing box 27 for rotatably supporting the driven wheel 26 is provided on a support frame (see FIG. (Not shown) to support the driven wheel 26 so as to position the driven wheel 26 on a narrow gauge or a wide gauge. Note that the inner peripheral surface of the axle 22 that supports the driven wheel 26 is constituted by a plain bearing 28 and the driven wheel 26 is freely rotatable, and a spline mechanism 29 is used in place of the plain bearing 28 to drive the driven wheel 26. There is a type in which the rotation of the axle 22 is transmitted to 26. Reference numeral 25 in FIG.
It is a bearing box on the third side.

Another prior art is disclosed in Japanese Patent Application Laid-Open No. 6-27.
There is a wheelset structure described in JP 0811-A1. Although not shown, in this structure, a pair of independent wheel shafts each provided with one wheel are provided on the same axis, a driving device is interposed between the left and right axles, and between the driving device and each axle. Are connected via a gear-type interior joint that allows axial displacement, and the gear-type interior joint has an internal gear having a number of teeth extending in parallel with the axial direction, meshes with the internal gear, and It consists of an external gear that can slide in the direction.

[0004]

However, the conventional variable gauge bogie axle described above has the following problems.

In the case of Japanese Patent Application Laid-Open No. 7-52795: In the former type, sufficient acceleration cannot be obtained because the rotational force of the motor is transmitted to only one wheel. In addition, the wheels on the driving side wear faster than the wheels on the driven side. Furthermore, in the curved part of the track, the turning force normally caused by the left and right driven wheels (due to the difference in wheel diameter) cannot be used. On the other hand, in the latter type, there is a possibility that fretting corrosion (small vibration wear) may occur at a spline portion between the driven wheel and the axle.

[0006] In the case of JP-A-6-270811: a central drive shaft and two left and right axles are connected by a tripod, and the rotational force is transmitted to the left and right wheels. In this method, the rotational force can be transmitted, but it cannot be transmitted in the yaw direction and the roll direction moment of the left and right wheels since it bends freely at the portion corresponding to the node of the tripod. A general axle requires only two bearings, but in this method, it is necessary to provide four bearings at both ends of the left and right two axles.
The structure is complicated and it is difficult to construct a bogie frame.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and enables the relative smooth rotation of a rotating shaft and a member to be rotated in the axial direction, and also ensures that the rotating force of the rotating shaft is applied to the member to be rotated. And a rotary joint structure that can transmit the moment due to the load on the left and right wheels, prevent fretting corrosion, improve the acceleration of the bogie, and reliably change the gauge of the wheels. It is an object of the present invention to provide a variable gauge bogie axle having the rotary joint structure, which can be stably performed and can generate a turning force between both wheels at a curved portion of a track.

[0008]

In order to achieve the above-mentioned object, a rotary joint structure according to the present invention comprises: a) a rotatable member mounted on the outer periphery of one rotary shaft so as to be slidable in the axial direction; A rotating joint structure for transmitting the rotating force of the rotating shaft to the rotated member, b) forming at least one arc-shaped long groove in the axial direction at the rotating member mounting position of the rotating shaft. And c) a plain bearing is provided on the inner peripheral surface of the rotated member, and d) an engaging portion that can be inserted into each of the long grooves and that can contact the long groove surface has a radius from the inner peripheral surface of the rotated member. And is provided rotatably about the radial axis .

According to a second aspect of the present invention, in the variable axle bogie wheel axle, the variable axle bogie axle is formed by the rotating shaft, and one or both wheels of the bogie are controlled by the rotatable member. Make up. When the wheel constituted by the rotated member is on one side, the other wheel is fixed to the axle.

It is preferable that the engaging portion is constituted by a rotor having a spherical surface having a radius shorter than a radius of the long groove that draws an arc at a portion in contact with the long groove.

According to a fourth aspect of the present invention, the three arc-shaped long grooves are formed on the rotating shaft at equal intervals in a circumferential direction.
The rotor is rotatably mounted via a bearing to the tip of a spindle that penetrates the member to be rotated inward in the radial direction, and the tip of the spindle is formed slightly larger by expanding the tip of the spindle. It is preferable that a seat surface of the bulging portion that comes into contact with the inner peripheral surface of the rotated member is formed in a spherical shape.

According to a fifth aspect of the present invention, one wheel is fixed to one end of the axle, and the other wheel is configured to be slidable in the axial direction along the long groove of the axle. May be fixed.

According to a sixth aspect of the present invention, both wheels may be configured to be slidable in the axial direction along the long groove of the axle, and the drive gear may be provided so as to be integrally rotatable with one of the wheels.

[0014]

According to the rotary joint structure of the present invention having the above structure (claim 1), a force is applied to one of the rotary members on the rotary shaft in one of the axial directions of the rotary shaft to thereby control the rotary member. The rotating member is guided by the long groove through an engagement portion inserted into a long groove of a circular cross section of the rotating shaft that protrudes in the radial direction from the inner peripheral surface of the rotating member, and slides in the axial direction. Then, when the member to be rotated slides along the rotation axis, a part of each engaging portion comes into contact with the arc surface of the long groove and the engaging portion supports this in the radial direction.
Since rotating about the axis, the movement of the engaging portion in the long groove can be smoothly performed. On the other hand, by rotating the rotating shaft in one direction by applying a rotating force to the rotating shaft, the rotating force is transmitted to the member to be rotated by the engagement relationship between the long groove arc surface and the engaging portion, and the member to be rotated is rotated. And rotate together. Also,
When a load acts on the rotated member in the radial direction with respect to the rotation shaft, the plain bearing on the inner peripheral surface of the rotated member comes into contact with the outer peripheral surface of the rotation shaft and is supported by the rotation shaft.
Therefore, even when a load is applied to the rotating shaft or the rotated member, the sliding of the rotated member with respect to the rotating shaft in the axial direction is performed smoothly.

[0015] According to the variable gauge bogie wheel set according to claim 2 having the above configuration, it corresponds to the gauge conversion track equipment, and when the distance between the wheels of the bogie is changed according to the change in the track distance. Then, one or both wheels slide axially along the arc-shaped long groove of the axle. At this time, a part of each engaging portion comes into contact with the arc surface of the long groove, and the engaging portion moves in the long groove while rotating, so that the wheel moves smoothly in the axial direction of the axle. In the case of a bogie, the load of the body normally acts on the axle, but the outer peripheral surface of the axle (excluding the portion of the arc-shaped long groove)
Is supported by a plain bearing on the inner peripheral surface of the wheel, and the load is shared, so that the movement of the wheel along the axle is not hindered. Needless to say, when the rotational force of the driving device is transmitted to the axle to rotate the axle, the rotational force of the axle is transmitted to the wheels by the engagement between the engagement portion and the arc-shaped long groove.

According to the third aspect of the present invention, as shown in FIG. 6, when a rotational force acts on the axle and the rotor as an engagement portion with the long groove comes into contact with the circular arc surface of the long groove, the rotor rotates. The spherical part makes point contact. For this reason, when the wheel slides in the axial direction with respect to the axle, the rotor moves while rotating in the long groove, and since the contact resistance is small due to point contact, the wheel slides smoothly. Done in

According to the fourth aspect, when the rotor is attached to the rotated member, the spherical seating surface of the tip bulging portion of each support shaft comes into contact with the inner peripheral surface of the rotated member, A centering action occurs. This allows the three rotors to rotate 12 circumferentially.
The rotors are arranged at regular intervals at an angle of 0 ° to prevent the rotor from hitting the arc surface of the corresponding long groove.

According to the wheel set for a variable gauge bogie described in claim 5, when the interval between the wheels of the bogie is changed in accordance with the change in the interval between the tracks, the one end of the axle slides on the opposite side to the fixed wheel. As the possible wheels move closer or further along the axle, the wheel spacing is changed. Further, usually, the rotation of the driving device arranged on the bogie frame is transmitted to the axle via the driving gear, and the fixed wheels and the slidable wheels rotate, so that the bogie is accelerated.

According to the wheel set for a variable gauge bogie, when the distance between the wheels of the bogie is changed in accordance with the change in the track interval, the slidable wheels at both ends of the axle face each other. By approaching or moving along the axle in the direction
Wheel spacing is changed. In addition, the rotation of the drive device usually arranged on the bogie frame is transmitted to one of the wheels via a drive gear, transmitted to the axle by the engagement between the engagement portion (rotor) and the long groove, and further transmitted from the axle. Long groove and engaging part (rotor)
Is transmitted to the other wheel by the engaging action with the axle, the wheels on both sides rotate integrally with the axle, and the bogie is accelerated.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the wheel set for a variable gauge truck according to the present invention will be described below with reference to the drawings.

FIG. 1 is a drawing showing a first embodiment of a variable gauge bogie wheel set. The upper half is a sectional view and the lower half is a front view. FIG. 2 is an enlarged view showing a main part of FIG.
2A is a sectional view of a portion A in FIG. 1, FIG. 2B is a sectional view taken along a line BB of FIG. 2A, and FIG. 2C is a line CC of FIG. 2A. It is sectional drawing.

As shown in FIG. 1, the variable bogie axle 1 of this embodiment has a boss 3 of a wheel 3 at one end (left side in the figure) of an axle 2.
a is press-fitted and fixed. Further, a boss 4a of the drive gear 4 is press-fitted into the axle 2 and fixed on the inner side of the fixed wheel (hereinafter, referred to as a fixed wheel) 3;
A bearing 5 supported by a bogie frame (not shown) is rotatably supported at an end of the axle 2 outside the fixed wheel 3.

On the other hand, a wheel 6 is disposed at an end of the axle 2 opposite to the fixed wheel 3 so as to be slidable in the axial direction. The wheels (hereinafter, also referred to as moving wheels) 6 are configured to be able to move a distance corresponding to the gauge gap difference between the wide gauge and the narrow gauge, and to be positioned on the wide gauge and the narrow gauge. That is, as shown in detail in FIG. 2 (b), three long grooves 7 having an arc-shaped cross section are provided at equal intervals of 120 ° in the circumferential direction of the axle 2 in the axle 2, and FIGS. ) Are formed in the axial direction of the axle 2 respectively.

The boss 6a of the moving wheel 6 is
As shown in FIG. 2A, a ring-shaped plain bearing 8 is attached to the annular grooves 6c provided at both ends of the inner peripheral surface of the boss portion 6a via the retaining ring 8a. Have been. The gap between the inner peripheral surface of the plain bearing 8 and the outer peripheral surface of the axle 2 is provided with a clearance (several microns to several tens microns). The boss 6a
Three rotors 9 as engaging portions corresponding to the elongated grooves 7 are arranged at intervals of 120 ° in the circumferential direction at a substantially intermediate portion in the axial direction of the rotor. Each rotor 9 is rotatably mounted around the central axis of the support shaft 10 via a bearing (not shown) at the tip end of the support shaft 10, and is penetrated through the boss portion 6a in the radial direction. The support shaft 10 is loosely inserted from the inside to the outside in the mounting hole 6d, and a nut 11 is screwed into a screw portion 10b formed at the base end of the support shaft 10, and is fixed by being tightened. In addition,
The nut 11 is housed in the recess 6e of the boss 6a.

Further, as shown in FIG. 1, stoppers 12 and 13 with which the boss 6a of the moving wheel 6 abuts are fixed to both sides of the long groove 7 of the axle 2. On the outer peripheral surface of the right end of the boss 6a, a bearing 14 is rotatably supported by a bogie frame (not shown) corresponding to the bearing 5 and similarly supported.

FIGS. 3A to 3C are enlarged sectional views showing different embodiments of the rotor 9 and the centering structure thereof. In the case of this example, as shown in FIG. 3A, the distal end portion 10c of the support shaft 10 is bulged to form an outer diameter larger than that of the main body portion 10a, and the seating surface 10 of the distal end portion 10c is formed.
c 'is formed in a spherical shape, the support shaft 10 is loosely inserted into the mounting hole 6d of the boss 6a, and the nut 11 is tightened, whereby the mounting hole 6d and each central axis of the support shaft 10 are aligned, and centering is performed. Like that.

In the structure shown in FIG. 3 (b), the outer diameter of the main body 10a of the support shaft 10 is considerably smaller than the inner diameter of the mounting hole 6d, and the distal end is positioned from a substantially intermediate position in the longitudinal direction of the support shaft 10. The outer diameter is gradually increased toward the conical portion 10d, and the distal end side of the mounting hole 6d is formed in a conical hole 6d 'corresponding to the conical portion 10d, and the conical portion 10d
And the conical hole 6d 'produces a centering action.

In the structure shown in FIG. 3C, the seating surface of the tip 10c of the support shaft 10 having the structure shown in FIG. A part 6a 'of the inner peripheral surface of the portion 6a is formed on a corresponding flat surface, and the centering is achieved by fitting the mounting hole 6d and the support shaft 10.

As shown in FIG. 2 (b), the rotor 9 has a main body 9a which is a part of a sphere large enough to be inserted into the arc-shaped long groove 7, and horizontally cuts the upper end thereof. It has a top surface 9b and a bottom 9c of the main body 9a formed in a disk shape. The radius of the sphere of the main body 9a is smaller than the radius of the arc surface of the long groove 7.

FIG. 6 shows the dimensional relationship between the rotor 9 and the opening of the long groove 7 in detail. FIG.
6B is an example in which the gap δ between the rotor 9 and the opening of the long groove 7 is reduced. First, in FIG. 6 (a), the center of rotation O ₂ of arcuate surface of the elongated groove 7 provided from the axial center O of the axle 2 on the circumference of a radius R _2, connecting the rotational center O ₂ and the axial center O center the position of the radius R ₁ from the center O on the line S, is provided with a rotation center O ₁ of the spherical surface of the body 9a of the rotor 9. In this positional relationship,
The radius of the arc surface of the long groove 7 is r ₂ , the radius of the spherical surface of the main body 9a of the rotor 9 is r ₁ , and R ₂ > R ₁ and r ₂ > r ₁ . Further, as shown in FIG. 6 (b), the long groove 7 across the center line S of the arcuate surface arcuate surface of the right side from the rotation center O ₂ to the left, also arcuate surface of the left side respectively from the rotation center O ₂ to the right by drawing an arc with radius r ₂ around a position by a predetermined dimension eccentric, it is possible to reduce the gap δ between the rotor 9 (position on the center line S) and the long groove 7 arcuate surface of the. However, these are examples for bringing the spherical main body 9a of the rotor 9 into point contact with the arc surface of the long groove 7, and are not limiting.

Next, the variable bogie wheel axle 1 of the embodiment described above.
The operation of the wheels of the variable bogie provided with the wheel set 1 (especially the gauge changing operation) will be described.

In the wheel set 1 shown in FIG.
14 is supported on the lower surface of a pair of left and right bogie frames (not shown) provided oppositely to the variable gauge bogie (not shown). The movable bearing 14 on the right side of the figure is supported by predetermined positioning portions (for narrow gauge and wide gauge) of a bogie frame (not shown) according to the change of the gauge. For example, when the position of the moving wheel 6 is changed from narrow gauge to wide gauge, the moving wheel 6
Together with the stopper 13 at the outer end of the axle 2. At this time, the load of the bogie supported by the moving wheels 6 is removed, and the rotor 9 inserted into the long groove 7 of the axle 2 makes point contact with the arc surface of the long groove 7, and the shaft of the axle 2 rotates while rotating. The moving wheel 6 is guided along the direction. Then, when it moves to the wide gauge position, it is positioned and supported again by a support frame (not shown). In this state, the load of the bogie (not shown) is applied to the moving wheel 6 and the axle 2 by the bearing 1.
4 will work. Normally, as shown in FIG. 2C, a portion (lower portion) other than the long groove 7 of the axle 2 contacts the plain bearing 8 of the boss 6a of the moving wheel 6, and a load is applied to the fixed wheel 3 side portion of the axle 2. It is shared and supported.

Incidentally, the above-mentioned gauge conversion work is usually performed while transmitting the torque of a drive motor (not shown) to the axle 2 via the drive gear 4 and rotating it in one direction. Axle 2
Is transmitted directly to the fixed wheel 3, but is transmitted to the moving wheel 6 by point contact between the arc surfaces of the three long grooves 7 and the (spherical) main bodies 9 a of the rotors 9.

FIG. 4 shows a second embodiment of the variable bogie wheel set. The upper half is a sectional view and the lower half is a front view. The difference between the wheel set 1 ′ of the present embodiment and the above-described embodiment is that the left and right wheels are configured as moving wheels 6, 6 ′, respectively, and can be moved in the axial direction along the long grooves 7, 7 ′ of the axle 2, respectively. The wheel body 6b of the moving wheel 6 ',
The inside and outside of the boss 6a are respectively extended, the bearing 5 'is rotatably mounted on the outside, and the boss 4a of the drive gear 4' is press-fitted on the inside so as to be integrally rotatable. .

Therefore, in the wheel axle 1 'of this embodiment, when the gauge is changed, the moving wheels 6, 6' on both sides move along the long grooves 7, 7 'in the directions facing each other, and are changed. When the moving wheels 6, 6 'move to the respective gauge positions, they are positioned and supported on a support frame (not shown) via the bearings 5', 14. The drive gear 4 'moves together with the moving wheel 6'. When the gauge is changed, the drive motor (not shown) attached to the support frame (not shown) is also displaced. It is. In the case of this example, the rotation of the drive motor (not shown) is transmitted to the moving wheel 6 ′ via the drive gear 4 ′, and the axle 2 is brought into contact (engagement) with the rotor 9 and the arc surface of the long groove 7. Is transmitted from the axle 2 to the other moving wheel 6 simultaneously by the contact (engagement) of the arc surface of the long groove 7 with the rotor 9 so that the wheels 6 and 6 ′ on both sides are integrally formed with the axle 2. Rotate.
Other operations and configurations are the same as those of the wheel set 1 of the first embodiment, and thus description thereof is omitted. In addition, common constituent members are shown in the drawings using common reference numerals.

Although the two embodiments of the variable bogie wheel axle according to the present invention have been described above, the present invention is not limited to these two embodiments and can be carried out as follows.

The main body 9 a of the rotor 9 is formed into a spherical surface corresponding to the arc surface of the long groove 7, and the rotor 9 is brought into line contact with the arc surface of the long groove 7 to transmit a rotational force, or to the arc surface of the long groove 7. The rotor 9 can be guided in the axial direction while rotating the rotor 9 in a line contact state.

The axle 2 of the wheel set 1 is a rotating shaft that is rotated by a drive motor or the like, and a rotatable member instead of the moving wheel 6 is slidably mounted in the axial direction on the outer periphery thereof. It can be configured as a rotary joint structure for transmitting force. Such a rotary joint structure can be used, for example, in a joint in which a large moment is applied in the direction in which the shaft is broken and sliding in the axial direction is required.

[0039]

As is apparent from the above description,
The rotary joint structure and the variable gauge bogie wheel set of the present invention have the following effects.

(1) In the rotary joint structure according to the first aspect, it is possible to smoothly move in the axial direction of the rotary shaft relative to the member to be rotated on the rotary shaft, and to apply a rotational force to the rotary shaft. The rotated member can be rotated integrally with the rotating shaft, and the rotating member can be moved in the axial direction of the rotating shaft while rotating.

(2) In the wheel set for a variable gauge bogie according to the second aspect, by disposing the wheel set on the variable gauge bogie,
When the distance between the wheels of the bogie is changed according to the change in the distance between the tracks according to the gauge conversion track equipment, it is possible to smoothly move in the axial direction of the axle while rotating one or both wheels.

(3) In the rotary joint structure or the variable gauge bogie wheel set according to claim 3, since the spherical portion of the rotor makes point contact with the arc surface of the long groove, when the wheel slides in the axial direction with respect to the axle, At the same time as the rotor moves while rotating in the long groove,
The moving resistance of the rotor is small.

(4) In the rotary joint structure or the variable gauge bogie wheel set according to the fourth aspect, since the centering action occurs, the three rotors are arranged at equal intervals of 120 ° in the circumferential direction. It is possible to prevent the rotor from hitting against the arc surface of the long groove.

(5) In the variable gauge bogie wheel set according to claim 5, when the gauge is changed, the other slidable wheel approaches or separates from the fixed wheel along the axle to reduce the distance between the wheels. At the same time, the rotation of the driving device is transmitted to the axle via the driving gear, and the fixed wheel and the slidable wheel rotate to accelerate the bogie.

(6) In the variable gauge bogie wheel set according to claim 6, when the gauge is changed, the movable wheel on both sides approaches or separates along the axle in opposite directions so as to change the distance between the wheels. At the same time, the rotation of the driving device causes the wheels on both sides to rotate integrally with the axle through the engagement of the driving gear and the engaging portion (rotor) with the long groove, thereby accelerating the bogie.

[Brief description of the drawings]

FIG. 1 is a view showing a first embodiment of a variable gauge bogie wheel axle according to the present invention, wherein an upper half is a sectional view and a lower half is a front view.

FIG. 2 is an enlarged view showing a main part of a wheel set for a variable gauge bogie shown in FIG. 1; FIG. 2 (a) is a sectional view of a part A in FIG. 1;
2B is a sectional view taken along line BB of FIG. 2A, and FIG. 2C is a sectional view of FIG.
It is CC sectional view taken on the line of FIG.

FIGS. 3A to 3C are enlarged sectional views showing different embodiments of the rotor 9 and the centering structure thereof.

FIG. 4 is a view showing a second embodiment of the variable bogie wheel axle according to the present invention, wherein an upper half is a sectional view and a lower half is a front view.

FIG. 5 is a front sectional view showing a variable gauge bogie wheel set according to the prior application.

6 is a rotor 9 in the variable gauge bogie wheel set of FIG. 1;
FIG. 4 is an explanatory diagram showing in detail a dimensional relationship between a groove and an opening of a long groove 7;
FIG. 6A is an example of a method of increasing the gap δ between the rotor 9 and the opening of the long groove 7, and FIG. 6B is a method of reducing the gap δ between the rotor 9 and the opening of the long groove 7. This is an example. [Brief description of drawings]

[Explanation of symbols]

 1.1 1 ′ Variable gauge bogie wheel axle 2 Axle 3 Fixed wheel 4 ・ 4 ′ Driving gear 5.5 ・ 5 ′ 14 Bearing 6 ・ 6 ′ Moving wheel 6a Boss section 7 ・ 7 ′ Long groove 8 Plain bearing 9 Rotor (engagement Part) 10 Support shaft 12.13 Stopper

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-52795 (JP, A) JP-A-6-298090 (JP, A) JP-A-5-75522 (JP, U) (58) Survey Field (Int.Cl. ⁶ , DB name) B61F 7/00 F16D 1/06

Claims (6)

(57) [Claims] A rotary joint structure for attaching a rotatable member to an outer periphery of one rotary shaft so as to be slidable in an axial direction, and transmitting a rotational force of the rotary shaft to the rotatable member. At least one arc-shaped long groove having an arc-shaped cross section is formed in the rotating shaft at the mounting position of the rotatable member, and a plain bearing is provided on an inner peripheral surface of the rotatable member, and can be inserted into each of the long grooves. and an engaging portion capable of contacting the long groove surface, the is projected radially from the inner circumferential surface of said rotary member
A rotary joint structure provided rotatably about a radial axis . 2. The variable gauge having a rotary joint structure according to claim 1, wherein an axle of the variable gauge bogie is constituted by the rotating shaft, and one or both wheels of the bogie are constituted by the rotated member. Wheelset for bogie. 3. The rotary joint structure according to claim 1, wherein the engaging portion is constituted by a rotor provided with a spherical surface having a radius shorter than a radius of the long groove in a portion in contact with the long groove. Item 2. The variable axle bogie wheel set according to item 2. 4. An end of a supporting shaft for forming the three arc-shaped long grooves on the rotating shaft at equal intervals in a circumferential direction, wherein the rotating shaft penetrates the rotor radially inward through the member to be rotated. The support shaft is rotatably mounted via a bearing, and the tip end of the support shaft is bulged to form a slightly larger portion. The seat surface of the bulge that comes into contact with the inner peripheral surface of the rotated member is spherical. The rotary joint structure or variable gauge bogie wheel set according to claim 3, wherein the rotary joint structure is formed in a shape. 5. A wheel is fixed to one end of the axle, and the other wheel is configured to be slidable in the axial direction along a long groove of the axle, and a drive gear is fixed to the axle. A variable axle bogie wheel axle according to any one of claims 1 to 4. 6. The vehicle according to claim 2, wherein each of the wheels is configured to be slidable in the axial direction along the long groove of the axle, and a drive gear is provided so as to be integrally rotatable with one of the wheels. Wheelset for variable gauge bogies.