JP3175866B2 - Optical fiber wheel speed sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel speed sensor device for detecting a wheel speed, and more particularly, to a light capable of performing electrical processing at a position distant from a wheel by using an optical fiber. It relates to a fiber type. Therefore, the present invention, in addition to ordinary vehicles such as automobiles,
It can also be used for magnetic levitation vehicles and aircraft.

[0002]

2. Description of the Related Art Generally, an optical wheel speed sensor device includes an encoder plate for detecting rotation information about a wheel, a light source for projecting light on the encoder plate, and a light source for emitting light to the encoder plate. Light receiving means for receiving light through the encoder plate. In addition, the optical fiber type further includes an optical fiber for transmitting optical information between the light source-encoder plate and the light receiving means-encoder plate. The optical fiber type has an advantage that the light transmission function of the optical fiber allows the light source and the light receiving means to be arranged in an environment where electric noise is likely to occur. Such an optical fiber type device is disclosed in Japanese Patent Application Laid-Open No. 62-174661 or
It is already known in the publications of 152969.

Here, there are two types of encoder plates, a transmission type and a reflection type. In each case, a large number of radial light supply lines (in the transmission type) which emit light signals in response to light projection from a light source. A disc-shaped plate having a transmission slit line and a reflection metal line in a reflection type.
In order to perform accurate and effective measurement, the encoder plate must be mounted on the shaft of the wheel without rotation and insulated from the external environment. Therefore, it is preferable that the encoder plate and the optical fiber be accommodated in a hollow axle. From this point, it is more likely that the light emitted and received by the encoder in the direction perpendicular to the axial direction of the axle will be used, as in the technology disclosed in Japanese Unexamined Patent Publication No. Sho 62-174661. In addition, it is better to transmit and receive light in a direction parallel to the axial direction. In the technique disclosed in Japanese Patent Application Laid-Open No. Sho 62-174661, a dedicated rotor for an encoder plate and a bearing for rotatably supporting the rotor are assembled in a housing. However, a structure that is more advantageous in terms of space is desired as a structure for supporting such an encoder plate and an optical fiber for transmitting light therethrough. This is because there are not only devices for detecting the wheel speed but also other detecting devices near the wheels, such as those for detecting the tire pressure of the wheels, the wear of the brake pads, and the temperature or pressure around the brakes. This is because it may be provided, and it is desirable that those parts are also arranged in the internal space of the axle.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a wheel speed sensor technology which is advantageous in coexistence with a device for detecting information other than wheel speed and which is advantageous in terms of space.

[0005]

According to the present invention, not only the wheel speed but also other information such as tire pressure is detected by using an optical fiber, and at least another information detecting optical fiber is used. One is configured to include a rotating portion that rotates with the wheel along the axis of the wheel and the axle. Then, the rotating portion of the other information detecting optical fiber is disposed in the axle, and the encoder plate is attached to and supported by the rotating portion with the center of rotation of each other being one. When detecting other information around the wheel, for example, tire pressure,
It is necessary to convert air pressure information obtained from a rotating tire portion into light information by a pressure-light conversion element (for example, a rubber optical fiber) and transmit the light information to a non-rotating side such as a chassis of a vehicle. In that respect, the rotating portion of the optical fiber can effectively transmit the optical information received from the pressure-light converting element to the non-rotating side, and furthermore, from the characteristics of light,
Even if there is a gap or space between the rotating optical fiber side and another information detecting light source or light receiving means located on the non-rotating side, nothing is transmitted to the optical transmission between the rotating side and the non-rotating side. No obstacles. In addition, since the rotating part of another optical fiber for information detection is supported so that there is no rotation blur at the center of the axle, the rotation of the encoder plate supported there is not likely to occur, and the space is limited. Can also effectively save labor.

[0006]

FIG. 1 is a sectional view showing a wheel portion of a magnetic levitation vehicle including a fiber optic wheel speed sensor device according to the present invention and a device for detecting tire pressure which is another information. First, the position of the wheel speed sensor device will be clarified with reference to FIG.

The main components of the wheels are an annular tire (pneumatic rubber tire) 10 which is in contact with the road surface during running and a wheel 12 which integrally supports the tire 10 on its outer periphery. The wheel 12 is rotatably supported around a hollow axle 14 via a bearing 16. Therefore, the tire 10
The wheel 12 belongs to the rotating side, and the axle 14 belongs to the non-rotating side. In the wheel 12 that opens in one direction,
A brake device for wheels is arranged on the outer periphery of the axle 14 close to the opening. A portion facing the opening of the wheel 12 has a piston housing 20. The piston housing 20 is a member that accommodates a brake piston 21 that can move in parallel with the axis of the axle 14, and is itself supported by the axle 14 and does not rotate like the axle 14.
A plurality of rotors 22R and stators 22S are alternately arranged in the internal space of the wheel 12 facing the brake piston 21. The disc-shaped rotor 22R is supported by a key 23 attached to the wheel 12, and
And it rotates according to the rotation of the wheel 12. On the other hand, the stator 22S adjacent to the rotor 22R is supported by the spline portion 25a of the torque tube 25 attached to the axle 14 via the piston housing 20, and holds the position without rotating. At the time of braking, when hydraulic pressure is supplied to the brake piston 21, the brake piston 21 pushes the rotor 22R via the stator 22S, and a braking force is generated by friction between the stator 22S and the rotor 22R. At this time, since a large amount of heat is generated, the space between the key 23 and the wheel 12 is
Heat shield plates 26a and 26b are provided between the torque tube 25 and the wheel 12, respectively. Also,
A temperature fuse 27 is provided in a portion of the wheel 12 facing the inside of the tire 10. This thermal fuse 2
Numeral 7 is for discharging the air pressure of the tire 10 in order to avoid an abnormal situation of the tire 10 when the wheel 12 is overheated by running and braking.

A tire pressure detecting device 50 for detecting the air pressure inside the tire 10 is for detecting an abnormality such as a puncture, and is for detecting a pressure for converting a change in the air pressure of the tire 10 into a change in the amount of light. A portion P, transmission means L for transmitting optical information to the portion P, and light source and sensor means for handling the optical information are provided. An optical fiber which is elastically deformed by receiving the pressure inside the tire is used as a part P for pressure detection, and another transmission means L which can be optically connected to the optical fiber of the P part by bonding. An optical fiber is used. As the optical fiber that is elastically deformed, a rubber optical fiber whose core and cladding are made of a rubber material such as silicone can be used. Rubber optical fiber
When the tire 10 is deformed by receiving the air pressure, the total reflection condition fluctuates, so that the amount of transmitted light is reduced, that is, the tire 10 functions as a pressure-light conversion element. The end of the latter optical fiber that transmits light to the rubber optical fiber is rotatably supported for signal transmission between the rotating side and the non-rotating side. In this regard, in the tire pressure detecting device 50, the end of the optical fiber to be rotatably supported is connected to the axle 14
And is supported by a bearing in a housing 70 inside the hollow axle 14.

On the inner periphery near the opening end of the cylindrical axle 14, there is a short inward flange 141, and a screw 142 is cut into the inner periphery of the axle 14 from the flange 141 to the opening. ing. A screw ring 60, a cap member 61, and a support member 62 are sequentially screwed to the screw portion 142. The screw ring 60 sandwiches the flange portion 71 of the housing 70 between the screw ring 60 and the inward flange 141, and fixes the housing 70 inside the axle 14.
At this time, the cap member 61 functions as a stopper for the screw ring 60. In addition, the support member 62, which is partially outside the axle 14, supports the hub cap 63 from the inside and functions to position the hub cap 63. Hub cap 63
Is located at the center of the wheel 12 and is fixed to the wheel 12 by a stopper 64 so as to cover the opening of the axle 14.

FIGS. 2 to 4 illustrate the structure of the housing 70 inside the axle 14. Housing 70
Has a plate-shaped first member 701 on the side of the cap member 61 and a second member 70 having a flange 71.
And a third member 703 farthest from the opening side.
The first member 701 and the second member 702 are
The second member 702 and the third member 703 are integrated with each other by a stop member 706 while being fitted and connected with each other by a stop member 705 with the support member 04 interposed therebetween. Such a housing 70 has a center hole 73 at a center portion along the axis of the axle 14, which has a different diameter but penetrates from one end to the other end. This center hole 73
, A rotating portion 110 of the first optical fiber 100 for tire pressure detection is rotatably supported by bearings 74a and 74b. The bearings 74a and 74b themselves are arranged at predetermined positions in the housing 70 by the C-shaped retaining ring 75a and the step of the second member 702, and by the spacer 76 and another C-shaped retaining ring 75b. In the center hole 73 of the housing 70, seal rings 77a, 77b are arranged so as to sandwich the bearings 74a, 74b on the axis of the axle 14. These seal rings 77a, 77b are
4a, 74b for dust prevention.

First optical fiber 10 for detecting tire pressure
As shown in FIG. 5, the rotation part 110 of the center 0 has a center-optical fiber 101 along the axis of the axle 14,
The eccentric-optical fiber 102 shifted from the axis of the axle 14 is integrated into the cable covering member 103. Each of the optical fibers 101 and 102 is a clad type having a core with a high refractive index inside and a clad with a low refractive index on the outer periphery. The rotating portion 11 of the first optical fiber 100
0 is connected to the third member 70 of the housing 70.
3 and faces the end face of the second optical fiber 200 for transmission for tire pressure detection with a gap of, for example, about 1 to 2 mm. Second optical fiber 200
Is disposed at the center of the third member 703 of the housing 70 by an optical connector 210 having a built-in condenser lens and a screw ring 220 holding the optical connector 210. Here, the second optical fiber 200 has a structure in which a large number of pixel fibers 201 are melted and integrated with each other and protected by a cable coating 202, as shown in the sectional structure of FIG. The second optical fiber 200 is the first optical fiber 200.
Unlike the optical fiber 100, which belongs to the non-rotating side,
The inside of the axle 14 can be drawn out to a location free from the influence of the strong magnetic field. Then, a light-emitting element as a light source and a light-receiving element (optical-electrical conversion element) as sensor means can be arranged at the drawn-out end.

On the other hand, the other end 110b of the rotating portion 110 of the first optical fiber 100 for detecting tire pressure is
It is located inside the cylindrical holder 65 at the center of the hub cap 63 and is butt-connected to the end face of another optical connector 120 supported concentrically with the axis of the axle 14 by the holder 65 (FIG. 1). And FIG. 4). Optical connector 1
20 is the center of the rotating part 110-an optical fiber 131 for transmission or lead extending from the optical fiber 101 and the hub cap 63, and the eccentric of the rotating part 110-another transmission or lead extending from the optical fiber 102 and the hub cap 63. The optical fibers 132 are connected to each other. These two optical fibers 131 and 132 as the transmission means L have one fiber inside, and one of them transmits the light from the light emitting element to the portion P for pressure detection, The other sends the light detected at the portion P back to the light receiving element side. These two optical fibers 131, 1
32 extends to the portion P while being supported on the surface of the wheel 12 by the clamp member 140 in the middle.

In the wheel speed sensor device 300 of the present invention, the rotating portion 1 of the optical fiber 100 for detecting tire pressure is used.
Focusing on the support structure of No. 10, it is used for supporting the encoder plate 400. In addition, the housing 70 itself that supports the rotating portion 110 of the optical fiber 100 is also used as a housing of the wheel speed sensor device 300. for that reason,
Second member 702 and third member 703 of housing 70
A gap 3 for accommodating the encoder plate 400
01 is provided. The transmission type encoder plate 400 having a large number of slits is rotatable in the gap 301 with the rotation of the rotating part 110 while being integrally supported by the support mechanism 310 around the rotating part 110 of the optical fiber 100. .

FIG. 7 shows a support mechanism 3 for the encoder plate 400.
10 is revealed. The support mechanism 310 includes a hub 312 that fits into the rotating part 110 and a screw ring 314 that is screwed to the hub 312 as main components.
In this structure, the encoder plate 400 is inserted between the screw ring 12 and the screw ring 314 and supported. Further, the hub 312 includes a screw portion 312 to which the screw ring 314 is coupled.
a, a large-diameter portion 312b having the same diameter as the screw ring 314, and a small-diameter portion 312 adjacent to the large-diameter portion 312b.
c. On the large diameter portion 312b of such a hub 312, there are two positioning pins 316, whereby
The slit of the encoder plate 400 is positioned.
Further, a set screw 3 is attached to the small diameter portion 312c of the hub 312.
18 are screwed together to secure the hub 312 to the rotating portion 110 of the optical fiber 100. According to the support mechanism 310,
The position of the encoder plate 400 can be accurately set on the rotating part 110 and can be fixed securely.

The wheel speed sensor device 300 includes an optical system including a transmission type encoder plate 400, a light source that projects light onto the encoder plate 400, and a light receiving unit that receives light passing through a slit of the encoder plate 400. It has. A light emitting element as a light source and a light receiving element for performing light-to-electric conversion (both not shown) are arranged on the same side with respect to the encoder plate 400 in terms of arrangement of electric circuits involved in light emission and light reception. In addition, in order to avoid the generation of electrical noise, the light emitting and receiving elements and the electric circuits related to them are located away from the housing 70. Light from the light source (light emitting element) is optically transmitted by light projecting optical fiber 360, a SELFOC lens
After being collimated by the lens 350, the SELFOC lens
The direction is changed by 180 ° by a right-angle prism 340 closely attached to 350 . The light whose direction has been changed is supplied to the encoder plate 400.
Is focused by the spherical lens 330 behind the
After passing through the slit of the damper plate 400 , the light receiving optical fiber 3
20 to the light receiving element.

The components of the optical system are collectively housed in a housing 70. The end of each of the optical fibers 360 and 320 for projecting and receiving light is connected to the third member 7.
The spherical lens 330, the right-angle prism 340, and the SELFOC lens 350 are installed so as to be able to be inserted into and removed from the holes provided in the second member 702. Optical fiber for tire pressure detection 1
Since the encoder plate 400 is supported with respect to the rotating part 110 of No. 00, the housing 70 for supporting the rotating part 110 can be used as a housing for optical components for transmitting and receiving light to and from the encoder plate 400. In order to reduce the loss of light, the slit of the encoder plate 400 is set on the focal point of the spherical lens 330, and the end of the selfoc lens 350 and the light emitting optical fiber 360 adjacent thereto are connected. It is placed in a cylindrical case cover 370, and the end face of the selfoc lens 350 is made to adhere to the surface of the right-angle prism 340.

The present invention relates to a transmission type encoder plate 400.
It is needless to say that the present invention can be applied not only to the transmission type using the device, but also to the reflection type.

[0018]

According to the present invention, the rotating portion 110 of the optical fiber 100 for detecting other information such as tire pressure is used.
In addition, since the encoder plate 400 for detecting the rotation information about the wheels is attached and supported, the encoder plate 400 is supported without rotation blur, and moreover, the space can be effectively saved. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a wheel portion to which a wheel speed sensor device according to the present invention is applied.

FIG. 2 is a side view showing a housing portion in the axle.

FIG. 3 is a sectional view taken along line 3-3 'of FIG.

FIG. 4 is a sectional view taken along the line 4-4 'in FIG.

FIG. 5 is a sectional view taken along the line 5-5 'in FIG.

FIG. 6 is a cross-sectional view taken along line 6-6 ′ of FIG.

FIG. 7 is a sectional structural view showing a support mechanism of the encoder plate.

[Explanation of symbols]

Reference Signs List 10 tire 12 wheel 14 axle 50 tire pressure detecting device 60 screw ring 70 housing 100 tire pressure detecting optical fiber (different information detecting optical fiber) 110 rotating part 300 wheel speed sensor device 340 right angle prism (reflecting means) 400 encoder plate

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01P 3/486-3/488 B60C 23/02

Claims (4)

(57) [Claims] 1. An encoder plate disposed in an axle located at the center of a wheel, for detecting rotation information about the wheel, a light source for projecting light on the encoder plate, and an encoder plate according to the light projection Fiber-optic wheel speed sensor device comprising a light receiving means for receiving light through the light source, and a wheel speed detecting optical fiber for transmitting optical information between the light source-encoder plate and the light receiving means-encoder plate, wherein the wheel or the vehicle to which the wheel belongs Another information detecting optical fiber is provided in the axle for detecting information other than the wheel speed, and includes a rotating portion along the axis of the axle and including a rotating portion that rotates with the wheel. An optical fiber, wherein the encoder plate is attached to and supported by a rotating portion of another optical fiber for information detection, with the centers of rotation of the two being the same. Iva-type wheel speed sensor device. 2. The optical fiber wheel speed sensor device according to claim 1, wherein said light source and said light receiving means are located on the same side with respect to said encoder plate. 3. A reflecting means for converting the light emitted from the light source by 180 ° and directing the light toward the light receiving means on the side opposite to the side on which the light source and the light receiving means are located with respect to the encoder plate. Optical fiber wheel speed sensor device. 4. The another information is a tire pressure of the wheel, and the another information detecting optical fiber transmits optical information from a rubber optical fiber that performs pressure-light conversion by elastic deformation. An optical fiber wheel speed sensor device according to claim 2 or 3.