JPH0672298A - Railway vehicle axle having detector for rotational speed incorporated therein - Google Patents

Abstract

PURPOSE: To provide an axle incorporated with a rotational speed detector which is compact, readily assembled and can perform precise detection in a low speed condition. CONSTITUTION: A sensor 31 is fixed to an immovable portion (second screen 20) of a labyrinth seal assembly 12 for protecting a bearing 6 which is provided between a rotational portion and a fixed portion 2 of an axle 3, while fixing an annular element 30 to a movable portion (first screen 15) of the assembly 12. The annular element 30 has substantially a uniform width in which an N pole and an S pole of a permanent magnet, for instance, are alternately arranged in a circumferential direction of the outer surface with a substantially predetermined pitch to generate periodic signals in proportion to the number of Ns and Ss that pass by the sensor 31 in a unit time, thereby detecting the rotational speed of the axle 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects the rotational speed of a wheel fixedly mounted on an axle (in the case of a bogie having independent wheels) or a plurality of wheels (in the case of a conventional rigid bridge bogie). The present invention relates to a railway axle incorporating a detector that does.

[0002]

2. Description of the Related Art A very dangerous situation occurs when wheels are locked during sudden braking. It is well known that such a problem of preventing wheel lock during sudden braking exists not only in road vehicles but also in modern high-speed trains, and therefore railroad bogies mounted on locomotives and freight cars. An anti-stick braking device, a so-called anti-lock braking system (ABS) device, has been developed that can be used for automobiles. As is well known, the bogie typically comprises a pair of axles, each supporting a pair of wheels, and in a rigid bridge bogie, two wheels are mounted on a single axle, one at each end. And the axis is
It is rotatably supported by respective supports which are connected to a bogie support structure which is connected to a freight car or a locomotive by suspension systems having shock absorbing arms. On the other hand, in the bogie of independent wheels, each wheel of each axle is supported by its own shaft, which is mounted in a protruding manner by its respective support, these supports being by suspension arms as in the previous case. Supported.

In both types of bogies, the rotational speed of the wheels is located in a fixed position in front of a toothed wheel, known as a "honic wheel" or "impulse ring" made of magnetic material and mounted on the shaft. Detected by the sensor,
The continuation of the hollow and solid parts due to the rotation of the shaft is defined by the presence of the teeth of the phonic wheel that continue to pass in front of the coil, causing the formation of a variable electrical signal across its terminals, the frequency of which Is proportional to the number of teeth passing in front of the sensor per unit time and thus to the rotational speed of the wheel or wheels mounted on the shaft with the phonic wheel. The signal generated by the sensor is then processed by an electronic central processing unit, which compares the signal with the signals generated by the other wheels of the bogie to determine the phenomenon of wheel sticking during braking. Detectable, and therefore the braking device can be controlled in a suitable manner.

[0004]

However, the above-mentioned device has drawbacks. In particular, the sensor and its associated phonic wheels are bulky and difficult to adjust, and therefore the assembly of the sensor and the phonic wheel, which is normally supported by the closing cover of the shaft bearing housing. It is troublesome in that it is essential to ensure complete centering between, otherwise the working of the device is poor, and finally the sensor has a low sensitivity at low speeds. , Therefore, the ABS device of the train is 5km / h
Does not detect velocities slower than up to 7 km / h.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a railway axle incorporating a detector in the axle without the problems of bulky rotation speed detectors and cumbersome assembly thereof. . It is also an integrated speed detector to provide an axle that can produce an effective signal even at low speeds.

The present invention secures a sensor to a stationary portion of a labyrinth seal assembly that protects a bearing between a rotating portion and a stationary portion of an axle, while securing an annular element to a movable portion of the assembly. . The annular elements have approximately the same width and are arranged at a substantially constant pitch in the circumferential direction, for example, the N pole, S of a permanent magnet.
The poles are arranged alternately, and the rotation speed of the axle can be detected by generating a periodic signal proportional to the number of N and S passing over the sensor per unit time.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

Referring to FIG. 1, the reference numeral 1 generally designates a railway axle having a generally known general construction, and therefore only the end portion of the axle for the sake of simplicity. The axle 1 comprises a fixing member, in a special case a support 2, which is connected in a known manner, not shown for the sake of simplicity, to a railway bogie which can be fastened to a known freight car or locomotive, not shown for the sake of simplicity. Only the part close to the one end 4 is shown and comprises a rotary member housed in a seat 5 formed in the support 2, a shaft 3 in a special case, the shaft 3 being in a known manner not shown for the sake of simplicity. Supporting at least one wheel to be mounted,
At least one rolling element bearing 6 is freely rotatably supported by the support 2, which bearing 6 is mounted on the shaft 3 for rotation, for example by an interference fit, on an inner ring 7
And an outer ring 8 fixedly mounted on the support 2 in the seat 5, and a plurality of rolling elements 9 interposed between the inner ring 7 and the outer ring 8. For example, the shaft 3 may be supported by a pair of opposed tapered roller bearings with a single row of rollers, or by a single tapered roller bearing with multiple rows of rollers. The seat 5 is closed in a well-known manner, not shown, by means of a cover 10 which is fixed to the support 2, for example by screws, and the well-known labyrinth type seal assembly 12 is provided with an end 4
Or rather at the end facing the exterior of the seat 5 and towards the cover 10.

In particular, the seal assembly 12 is bounded by a washer 18 which is mounted on a spacer ring 16 which is mounted concentrically on the end 4 and which is centered and fixed by means of screws 19 on the end face of the shaft 3. A first rigid screen 15 held in contact with the inner ring 7 by an axial fixing element fixedly supported by the end 4 and a second rigid screen which is firmly fixed directly to the outer ring 8 in a known manner. And a screen 20. The first screen 15 has a C in a radial cross section.
A ring shaped member, the recess of the ring member facing towards the spacer ring 16, the ring member of the bearing inner ring 7 and ring 16 being axially fixed to the shaft 3. The second screen 20 is clamped in between, while the second screen 20 is defined by a ring member having a U-shaped radial cross-section and an L-shaped ring projection 22 radially outward in cross-section, which ring member is, for example, an outer ring. Seat 2 of 8
Fastened in 3 and joined to the outer ring 8, thus the second screen 20 is axially fixed with respect to the outer ring 8 and is arranged with its recess facing the screen 15, Furthermore, the screens 15 and 20 protect the rolling elements 9 from external contaminants such as water and dust that can enter the seat 5, and at the same time, any lubricating grease that comes into contact with the rolling elements 9 is removed from the inner ring 7 and the outer ring 8. And a labyrinth seal 12 configured to be retained between and partially interfit with each other in a manner that limits the space therebetween. In a particular example, the ring portion 2 radially outside the screen 15
5 is inserted with a gap in the recess of the screen 20, while the ring portion 26 on the radially inner side of the screen 20 is the recess of the screen 15 in the annular space lying between the portion 25 and the spacer ring 16. Fit in with a gap and extend partially into the recess of the screen 15 and thus are generally facing the part 25. In this way, the substantially sealed chamber 28 with the recess of the screen 20 facing towards it is provided with the inner ring 7 and outer ring 8 and the screen 1
The seat 5 is formed between the seats 5 and 20.

Referring also to FIGS. 2-4, the seal assembly 12 further comprises an annular element 30 fixed for rotation therewith on the shaft 3, or rather on the rotating member of the axle 1. The element has a plurality of regions which are discontinuous in the case of permanent magnetized regions which have a substantially uniform width and are arranged circumferentially at a substantially constant pitch, and which are fixed members of the axle 1, ie supports 2. Well-known sensor 31 fixedly attached to
Is located in the seat 5 close to the annular element 30 and the magnetized region passes through the sensor to generate a periodic signal having a frequency proportional to the number of magnetized regions passing through the sensor per unit time. Is configured to be activated by. In the particular example shown, the annular element 30 is supported by the ring portion 25 of the screen 15 on the side facing towards the portion 22 of the screen 20, while the sensor 31 corresponds to the axial position of the element 30. The screen 20 is axially displaced from the position in the radial direction.
It is housed in the recess of and is supported by the screen 20. Finally, both the element 30 and the sensor 31 are housed in a chamber 28 which is sealed in a tight facing relationship,
The element 30 is free to rotate with respect to the sensor 31, together with the screen 15, the inner ring 7, the spacer ring 16 and the shaft 3, while the sensor 31 causes the outer ring 8 and the support 2 to rotate.
Maintained stationary at.

As shown non-restrictively in FIG. 2, element 30
Comprises bipolar magnetized regions 33, 34 which alternate between the N-pole region 33 and the S-pole region 34, in which case the well known magnetoresistive or preferably Hall effect type sensor 3 is provided.
1 is used for axle 1. According to the two possible variants shown in FIGS. 3 and 4, the element 30 is not magnetized in a dipole, but only in the region 33 (FIG. 3) defining all north poles or in all south poles. It may also be provided with unipolar magnetized regions only in the limiting region 34 (FIG. 4), in which case the regions 33 (or 34) are circumferentially arranged relative to each other to achieve the desired discontinuity. Formed in such a manner that they are spaced apart and thus separated by the non-magnetized regions 35, in these variants all Hall-effect or preferably magnetoresistive sensors 31 known in the art are used. Used for.

In the preferred embodiment, the element 30 uses rubber filled with a magnetizable material, such as a metal or oxide or alloy powder of a permanent magnet material, which is processed by well known molding techniques such as injection molding or compression. By doing
It is made in any of the modes shown in FIGS. Alternatively, a resin material filled as described above may be used, or the element 30
The magnetic powder material may be completely molded by sintering. The element 30 may be molded into a ring and rigidly secured radially outward of the portion 25, for example by gluing during the vulcanization stage by known techniques. However, in a possible variant not shown for the sake of simplicity, the element 30 may be made in one piece with the screen 15 and, in this case, constituted by the part 25 itself. In any case,
Permanently magnetized regions 33, 34 are conventionally obtained using similar techniques which are well known and therefore not described here for the sake of simplicity, such techniques producing magnetization by magnetic hysteresis effects. It is only shown to include exposing the region to be magnetized in a manner to a strong local magnetic field. In all cases, the sensor 31 is mounted on the screen 20 and provided with a cable 40 extending from the screen 20 to the outside of the chamber 28 and housed in the support 2 in order to collect the signals generated thereby.

In use, the rotation of the wheels of the train causes the rotation of the axle 3 and thus of the screen 15, while the screen 20 is fixed to the support 2 and does not rotate, as described above. The screen 15, which is concentric with 20, rotates with respect to the screen 20 in the recess of the screen 20 and produces a hydraulic sealing action on the one hand and the passage of regions 33, 34 through the sensor 31 on the other hand. If a Hall effect sensor is used, it is externally powered by a suitable, well-known electronic circuit, not shown for simplicity, and opens or closes each time region 34 passes after region 33 passes. It behaves as an opposite switch. In all situations, and thus even at very low rotational speeds, the sensor is a function of the rotational speed of the shaft 3 and is therefore calculable by a suitable circuit and of a known ABS unit not shown for simplicity. It produces a pulse signal of constant amplitude and frequency which is sent to the central control unit, for example by cable 40. In the case of a magnetoresistive sensor, the end result is similar (generating a signal with a frequency proportional to the rotational speed of the screen 15 and always high and well detectable intensity), but with varying The electronic control circuit and the detection circuit are different, which are well known in both cases and may be mounted on the outside of the seat 5, or may be miniaturized and mounted directly on the screen 20 with the sensor 31. May be.

From the above, the advantages associated with the present invention are obvious and the phonic wheel and cover 10 mounted on the end 4 of the shaft 3 as in devices well known in the art.
The costs and assembly and bulk problems caused by the presence of electromagnetic sensors mounted on the chassis are completely eliminated. In effect, the detector consisting of the element 30 and the sensor 31 is incorporated in a small sized sealed unit 12 which is necessary in any case for reasons of protection of the bearing 6.

[0015]

EFFECTS OF THE INVENTION According to the invention, there are no problems associated with the processing costs required to ensure the correct positioning of the sensor with respect to phonic elements as in the prior art. In effect, the invention ensures that the positioning is achieved by means of two screens which utilize the centering provided by the outer ring 8 and the spacer ring 16. Also provided is a device capable of accurately detecting the rotational speed even at low speeds.

[Brief description of drawings]

1 is a longitudinal sectional view of a terminal portion of a railway axle according to the present invention.

FIG. 2 is a diagram showing alternating N and S poles of a magnetized region.
FIG. 7 is a partial perspective view of an annular element incorporated into the axle of the vehicle.

FIG. 3 is a partial perspective view of an annular element having alternating N-pole regions and non-magnetized regions.

FIG. 4 is a partial perspective view of an annular element having alternating south pole regions and non-magnetized regions.

[Explanation of symbols]

 1 Rail Axle 2 Support 3 Axle 4 End 5 Seat 6 Rolling Element Bearing 7 Inner Ring 8 Outer Ring 9 Rolling Element 12 Rabinrinse Seal Assembly 15 First Rigid Screen 16 Spacer Ring 19 Screw 20 Second Rigid Screen 22 Ring Protrusion 25 Ring Part 30 Annular element 31 Sensor 33 N-pole region 34 S-pole region 35 Non-magnetized region 40 Cable

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Dario Bertreli Italy 10024 Montcalieri Strada Maiore 29 (72) Inventor Mateo Genero Italy 10026 Santenavia Sambai 99

Claims (7)

[Claims] 1. A seal assembly, which is housed in a seat defined between a fixed member and a rotating member of an axle and is configured to protect the rolling elements thereof, is provided at least toward the outside of the seat. An annular element of the seal assembly in a railway axle supported by a member fixed via one associated rolling element bearing and fitted with a detector incorporated therein sensitive to the rotational speed of the rotating member of the axle. Is fixed so as to rotate together with the rotating member of the axle, is provided with a plurality of discontinuous regions having approximately the same width and arranged in the circumferential direction at a substantially constant pitch, and By means of a fixing member of the axle, which is arranged to be activated by passing the region through it to generate a periodic signal having a frequency proportional to the number of the region passing through it in a unit time Supported A railway axle, wherein a sensor is provided in the seat proximate to the annular element of the seal assembly. 2. The railway axle according to claim 1, wherein the annular element of the seal assembly comprises two pole magnetized regions alternatingly defining north and south poles, the sensor being a Hall effect sensor. Alternatively, a railroad axle that is a magnetoresistive sensor. 3. A railroad axle according to claim 1, wherein all N elements of said seal assembly are circumferentially spaced from one another in such a manner that they are separated by a non-magnetized region. A unipolar magnetized region that defines a pole or south pole,
A railway axle, wherein the sensor is a Hall effect sensor or a magnetoresistive sensor. 4. The rotating member is defined by an axis,
The securing member is defined by a support for the shaft, the seat is formed within the support, and the seal assembly is disposed toward one end of the shaft facing outwardly of the seat. The railway axle according to any one of claims 1 to 3, wherein the annular element having the discontinuous region is concentrically mounted on a spacer ring concentrically mounted on the end of the shaft, A first of the seal assembly held in contact toward an inner ring of the bearing by an axial locking element fixedly mounted by the end of the shaft.
Forming a part of a rigid screen, the first screen
A concave ring member defined by a ring member clamped between the spacer ring and an inner ring of the bearing with its recess facing the spacer ring, the seal assembly being provided radially outside the ring protrusion. A second rigid screen defined by
A railway axle, characterized in that it is fixedly fixed to the outer ring of the bearing by the ring projection with its recess facing the first screen, the second screen supporting the sensor. 5. A railroad axle according to claim 4, wherein the first and second screens are partially axially fitted within each other in a manner to define a labyrinth seal therebetween. A radially outer ring portion of the first screen is inserted into the recess of the second screen and fixedly supports the annular element having the region of discontinuity, the sensor defining the region. A railway axle, which is accommodated by the second screen in a recess of the second screen at an axial position corresponding to the axial position of the annular element, but displaced radially outward of the position. . 6. The railway axle according to claim 4, wherein the annular element of the seal assembly having the regions of discontinuity is made of rubber filled with magnetizable material and secured to the first screen. Railway axle, wherein the sensor has a device for collecting the signal emitted by the sensor, the device extending from the second screen and accommodated by the support. 7. The railway axle according to claim 4, wherein the annular element of the seal assembly having the region of discontinuity is formed by sintering magnetic powder and is fixedly fixed to the first screen, Railroad axle, characterized in that the sensor comprises a device for collecting the signal emitted by it, the device extending from the second screen and accommodated by the support.