EP0357026B1

EP0357026B1 - Axle box suspension

Info

Publication number: EP0357026B1
Application number: EP19890115995
Authority: EP
Inventors: Akira Iwamura; Shuji Akashi
Original assignee: Kawasaki Heavy Industries Ltd; Kawasaki Jukogyo KK
Current assignee: Kawasaki Heavy Industries Ltd; Kawasaki Motors Ltd
Priority date: 1988-09-01
Filing date: 1989-08-30
Publication date: 1993-11-03
Anticipated expiration: 2009-08-30
Also published as: EP0542722A1; DE68910440D1; EP0357026A3; DE68922410D1; DE68922410T2; EP0357026A2; DE68910440T2; EP0542722B1

Description

The invention relates to an axle box suspension for mounting axles of a railway vehicle to a truck frame thereof according to the introductory portion of claim 1.
Such an axle box suspension is disclosed in GB-A-2 193 941. However, there is no disclosure nor a hint of an adaption of a sectional shape of said anchor rod in order to equalize the twisting rigidity thereof to that of said resilient member to substantially the same degree, and with this preknown construction the relevant portion of the rail bogie wheels sets absorps the radial force alone.
An axle anchor rod type axle box suspension for mounting the axle of a railway vehicle to a truck frame is already disclosed, for example, in Japanese Patent Laid-Open No. 58-63568 and No. 58-118447. Figs. 6 and 7 show its conventional example. In the drawings, numeral 13 denotes a wheel, which is mounted on the same axle 1 as that of a wheel (not shown) provided at the opposite side of the vehicle. Such two axles are mounted in the vicinities of both the ends of a truck frame 12, thereby constructing one truck. Numeral 3 denotes an axle box which contains a bearing 2 and so on of the axle 1. At the right side of the drawing of the axle box 3 is provided an axle anchor rod 3' formed integrally with the axle box, and rotatably slidably supported by a pin 8' wound with a resilient element 7a to the truck frame 12. At the left of the drawing of the axle box 3 is connected one end of a link 11 by a pin 10, and the other end of the link 11 is coupled to the truck frame 12 through the resilient element 7b. Numeral 6 denotes an axle spring, which buffers relative upward and downward movements between the truck frame 12 and the axle 1.
In this axle box suspension, the upward and downward vibrations occurred between the truck frame 12 and the wheel 13 are allowed by rotatably sliding the pins 8' and 10.
An axle anchor rod type axle box suspension shown in Figs. 8 and 9 eliminates a sliding section, in which an axle anchor rod 3' is coupled to a truck frame 12 by a pin 8' wound with a resilient element 7a. Since the axle anchor rod 3' is of a cantilever beam, two sets of resilient elements 7a and pins 8' must be provided as shown in Fig. 9 so as to resist against an external force applied in an axle direction.
Further, in order to prevent the reduction of a wheel load (or a derailment caused at its final stage of the reduction) due to an external force in an axle direction and an irregularity of tracks of rails, a bearing supporting resilient element 7c is wound between a bearing 2, the axle box 3 and a bearing retainer 5.
The performance required for a recent railway vehicle includes high speed running performance, easiness of maintenance and a reduction in a vehicle weight to reduce a damage imposed on the rails, and so on.
However, as designated by the conventional example in Figs. 6 and 7 in the prior art, when the vehicle is coasting, the performance of absorbing a vibration in an axle direction of the vehicle is deteriorated due to slides and gaps between the pin 8' and the resilient element 7a, between the pin 8' and the truck frame 12, and between the pin 10 and the link 11, so that the running stability of the vehicle is reduced, and that running ability at high speed is also greatly reduced. Further there arise more problems such as deterioration in the running performance of the vehicle due to the aging wears of the slide sections and the gap sections and complication in its maintenance due to lubrication and replacement of the components thereof.
On the other hand, in the conventional example shown in Figs. 8 and 9, there are not slides and gaps in the axle box suspension, but its axle anchor rod is increased in size and in weight, and a space for mounting the same is broadened. Further, as shown in a sectional view of the axle anchor rod 3' in Fig. 10, since the axle anchor rod 3' has a large twisting rigidity in a rotating direction I, (i.e., in a running direction) and a wide interval in the axle direction of the resilient elements 7a, the twisting rigidity between the axle anchor rod 3' and the truck frame 12 is large. Accordingly, it is necessary to also provide the resilient element 7c at the bearing 2 so as to prevent the reduction of the wheel load (or the derailment) which is possibly caused when the track is twisted due to the irregularity in the track or a reduction in the cant (the difference of the heights between an inside rail and an outside rail at a curve), thereby problems such as a complicated construction and an increase in the weight of the axle box 3 are caused.

SUMMARY OF THE INVENTION

This invention is made to solve the above-described problems of the prior art, and an object of the invention is to provide a light-weight axle box suspension which has high running stability at a high speed and a reduction in its maintenance work.
In order to achieve the above-described object, there is provided an axle box suspension according to claim 1, and further embodiments are claimed in subclaims 2-4. Advantageously, said axle box suspension has an axle anchor rod of selected sectional shape which is integrally coupled to the truck frame through a shaft and a resilient element. As a result, twisting rigidity of the vehicle in the running direction of the vehicle is imposed on both the axle anchor rod and the resilient element.
The operation of this invention will be described with reference to Figs. 1 and 2.
The axle box body 4 is formed integrally with the axle box 3 and the axle anchor rod 3', and is mounted at the truck frame 12 through the resilient element 7 in such a manner that there is no slide and gap.
The relative vertical movements between the axle 1 and the truck frame 12, which is equivalent to a swivel movement of the axle box body 4 around the shaft 8, is allowed by the deformation of the resilient element 7 provided between the axle anchor rod 3' and the truck frame 12.
Since the axle anchor rod 3' allows a twist in the running direction of the vehicle, and is coupled in series with the twisting rigidity of the resilient element 7, then the composite twisting rigidity between the axle box body 4 and the truck frame 12 is reduced, whereby the relative displacement of rolling between the axle 1 and the truck frame 12 can be easily allowed, so that the axle box and the axle can follow the longitudinal, lateral and vertical vibrations between the axle and the truck frame as a whole without rattling phenomenon.
Other objects and features of the invention will be more fully understood from the following detailed description and appended claims when taken with accompanying drawings.

Brief Description of the Drawings

Fig. 1 is a front view of an axle box suspension according to a first embodiment of this invention;
Fig. 2 is a sectional view taken along the line A-A of Fig. 1;
Fig. 3 is a sectional view taken along the line B-B of Fig. 1 or 6;
Fig. 4 is a front view of a second embodiment of this invention;
Figs. 5A and 5B are sectional views showing a modified example of the sectional shape of an axle anchor rod;
Figs. 6 and 7 are views of a conventional example of an axle box suspension, wherein Fig. 10A is a front view, and Fig. 7 is a sectional view taken along the line J-J of Fig. 6;
Figs. 8 and 9 are view of other conventional example, wherein Fig. 8 is a front view, and Fig. 9 is a top view; and
Fig. 10 is a sectional view taken along the line H-H of Fig. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

There will now be described preferred embodiments of the present invention with reference to the drawings.
Referring to Figs. 1 to 3. An axle anchor rod 3' extending in the same direction as the running direction C of a truck is integrally provided at an axle box 3, which is supporting the axle 1 with a wheel 13, forming an axle box body 4. The axle box body 4 is mounted to a truck frame 12 through an axle spring 6, but the axle anchor rod 3' is shaft-coupled by a resilient element 7 and a shaft 8 at the axle anchor rod support of the truck frame 12.
The resilient element 7 is adhered to the shaft 8 and is force-fitted into the axle anchor rod 3', so that there is no slipping part in this structure. The shaft 8 and the truck frame 12 are coupled by a tapered shaft fitting or a bolt clamping which also makes the structure with no slipping parts. Accordingly, the axle box body 4 is allowed to swivel in a direction E around the shaft 8 as a center by means of the deformation of the resilient element 7. Thus, the axle 1 is allowed in vertical relative movements in a direction F to the truck frame 12 through the axle box body 4.
The resilient element 7 transmits a propulsion force and a brake force in a direction C (same as the running direction) and lateral force in a direction D (same as the axle direction) from the axle 1 to the truck frame 12 through the axle box 3 and the axle anchor rod 3'.
As described above, a displacement between the axle box body 4 and the truck frame 12 is allowed by means of the deformation of the resilient element 7. Since there is no slip and particularly no gap in a direction C (same as the running direction of the vehicle), the axle box suspension does not rattle, so that running stability is enhanced and the vehicle is enabled to run at high speed. Furthermore, since there is no sliding or slipping parts, the gap is not increased due to aging wear as the conventional one, the deterioration of the running performance can be prevented, so that the replacement of worn components is eliminated, and maintenance can be easily done. As compared with the conventional example, the link and the pins are eliminated, whereby weight of the axle box suspension can be reduced. Further, it is made easy to assemble because of its simple structure.
In the present invention, since the twisting rigidity of the resilient element 7 can be coupled in series with that of the axle anchor rod 3' in the present invention, the twisting rigidity between the axle box body 4 and the truck frame 12 can be reduced.
Fig. 3 is a sectional view of the axle anchor rod 3'. When the twisting rigidity of the axle anchor rod in a direction G (same as the running direction) in the drawing is designated by K1 as shown in Fig. 2 and the twisting rigidity of the resilient element 7 in the direction G is designated by K2, the composite twisting rigidity K of the axle anchor rod 3' and the resilient element 7 is obtained from the formula $1/K = 1/K1 + 1/K2$

, and thus the combined twisting rigidity is smaller than K1 or K2.
Further, the K1 and the K2 are equalized substantially to the same degree thereby to reduce the composite twisting rigidity K of the K1 and the K2 with good balance without decrease of the strengths of the axle anchor rod 3' and the resilient element 7. As a result, the relative displacement is allowed in the rolling direction between the axle 1 and the truck frame 12. Therefore, the vehicle can follow the twist of the track due to an irregularity in the track or a reduction in the cant of the rails, thereby preventing the reduction of the wheel load generated by the twist of the rails (if the reduction of the wheel load is increased, derailment will finally be caused).
Fig. 4 shows a second embodiment of the invention. An axle spring 6 is engaged between a truck frame 12 and an axle box 3. The other construction is the same as that of the previous embodiment.
The twisting rigidity of the axle anchor rod 3' is suitably selected by setting its sectional shape in combination with the twisting rigidity of the resilient element 7.
Figs. 5A and 5B show other examples of the sectional views of an axle anchor rod 3'. Thus, the twisting rigidity of the axle anchor rod 3' in a direction G in Fig. 3 can be selected by suitably setting the sectional shape of the axle anchor rod 3' as described above.

Claims

An axle box suspension for mounting axles of a railway vehicle to a truck frame (12) thereof comprising:
an axle box body (4) including an axle box (3) and an axle anchor rod (3'), said axle box (3) supporting said axle (1) with a bearing (2) provided therearound, and said axle anchor rod (3') being integrally formed with said axle box (3) and extending to one side therefrom;
an axle spring (6) engaged between said axle box body (4) and said truck frame (12);
said axle anchor rod (3') being coupled to said truck frame (12) through a shaft (8) and a resilient element (7), thereby sharing a twisting rigidity of said vehicle as taken axially in the running direction thereof between said axle anchor rod (3') and said resilient element (7),
characterized in that
the twisting rigidity of said anchor rod (3') being selected by setting its sectional shape and being equalized to the twisting rigidity of said resilient element (7) to substantially the same degree,
said resilient element (7) including a bush section and a pair of flange sections at both ends of said bush section, said resilient element (7) and said shaft (8) being engaged with each other in complementary relationship.
The axle box suspension according to claim 1,
wherein said shaft (8) is provided in such a manner that there occurs no slipping phenomenon among said shaft (8), said truck frame (12) and said resilient element (7).
The axle box suspension according to claim 1 or 2,
wherein the twisting rigidities of said axle anchor rod (3') and said resilient element (7) are equalized to substantially the same degree.
The axle box suspension according to a preceding claim, wherein said axle anchor rod (3') allows the displacement of said truck frame (12) in the running direction of said vehicle, the displacement thereof in a swiveling direction around said shaft (8) as a central position and the displacement thereof in an axle direction.