JP2004066849A - Transmitter for tire state monitoring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmitter for a tire state monitoring device capable of easily securing an optimum installation state. <P>SOLUTION: A casing 10 is pivotally supported by a rotating shaft 31 penetrating a through hole formed on respective connecting arms 29 and a through hole formed on respective connecting protrusions 28 of a valve stem 11. A torsion coil spring 35 is loosely fitted on the rotating shaft 31, an end 35a of the torsion coil spring 35 abuts with an upper surface of the casing 10, and the other end 35b abuts with a plane surface 25 of the end part of the valve stem 11. The casing 10 is always energized to a drop center part 5b by elastic force of the torsion coil spring 35, and a protrusion 10a thereof is abutted with the drop center part 5b. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transmitter for a tire condition monitoring device, and more particularly to a transmitter mounted on a wheel on which a tire is mounted in order to transmit information on tire air pressure to a receiver provided in the vehicle.
[0002]
[Prior art]
In recent years, mainly from the viewpoint of ensuring safety during traveling, a wireless tire condition monitoring device is becoming widespread in order to check the condition of a tire mounted on a vehicle in a passenger compartment.
[0003]
As shown in FIG. 5, such a tire condition monitoring apparatus includes a transmitter 50 that transmits information related to tire air pressure to a receiver (not shown) provided in the vehicle interior. The transmitter 50 includes a casing 51 having a box shape and a valve stem 52 provided integrally with the casing 51. The casing 51 houses an electronic board (not shown) on which circuit elements such as a pressure detection element and each signal processing element are mounted, and a battery (not shown) for supplying driving power to these circuit elements. A ventilation hole (not shown) is formed in the casing 51.
[0004]
As shown in FIG. 6, the transmitter 50 is attached to the valve hole 63 of the tire wheel 62 so that the casing 51 is located in the internal space of the tire 61. Air injected from the valve stem 52 is discharged into the tire 61 through the vent hole.
[0005]
[Problems to be solved by the invention]
By the way, in order to reduce the weight of the transmitter, the casing 51 is formed of a resin material. However, centrifugal force acts on the transmitter 50 attached to the tire wheel 62 when the vehicle travels. This centrifugal force corresponds to the diameter of the tire wheel 62, the outer diameter of the tire 61, and the traveling speed of the vehicle, and is, for example, about 1500 G at 300 km / h. This centrifugal force acts to deform the casing 51 of the transmitter 50 in a direction away from the tire wheel 62. As a result, in the conventional transmitter 50 in which the casing 51 and the valve stem 52 are integrally formed, when the casing 51 is deformed against its own elastic force, stress is applied to the electronic board accommodated in the casing 51. This may cause problems such as poor electrical connection due to mechanical stress.
[0006]
Further, when the tire 61 is attached to and detached from the tire wheel 62, the bead portion 61 a of the tire 61 passes over the casing 51 of the transmitter 50 as shown in FIG. 6. At this time, the casing 51 of the transmitter 50 is pressed toward the tire wheel 62 by the bead portion 61 a of the tire 61. In particular, when the angle formed by the rotation axis of the tire wheel 62 and the central axis of the valve hole 63 of the tire wheel 62 (hereinafter, the formation angle of the valve hole 63) is large, the casing 51 has a drop center portion of the tire wheel 62. Separated from 62a. In this case, the bead portion 61a of the tire 61 does not easily pass over the casing 51 of the transmitter 50, and the degree of the pressing force against the casing 51 by the bead portion 61a increases, and the electrons housed in the casing 51 are increased. The probability that a defect will occur in the substrate increases.
[0007]
Conventionally, in order to prevent such a problem, the inclination angle between the casing 51 and the valve stem 52 is set to be equal to or larger than the formation angle of the valve hole 63 in advance so that the casing 51 does not always contact the drop center portion 62a of the tire wheel 62. The transmitter 50 was formed as follows.
[0008]
However, the valve hole 63 of the tire wheel 62 is formed at an angle within a predetermined range (15 to 25 degrees) with respect to the rotation axis of the tire wheel 62, and the position of the valve hole 63 also varies. Further, the inclination of the rim 62b with respect to the drop center portion 62a of the tire wheel 62 varies from product to product from the viewpoint of design. Therefore, in order to ensure an optimal mounting state with the conventional transmitter 50 in which the casing 51 and the valve stem 52 are integrally formed, the inclination angle between the casing 51 and the valve stem 52 optimized for each product. It is necessary to form the transmitter 50 having the above-mentioned, which has been a cause of increasing the manufacturing cost.
[0009]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a transmitter of a tire condition monitoring device that can easily secure an optimum mounting condition.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a casing that is disposed inside a tire mounted on a vehicle and houses various electrical components for measuring the state of the tire, and the tire are mounted. A transmitter for a tire condition monitoring device that transmits data indicating the condition of the tire, and the casing is substantially orthogonal to the outer peripheral surface of the wheel with the connecting portion as an axis An urging means is provided that is coupled to the valve stem so as to be pivotable in a direction to urge the casing toward the outer peripheral surface.
[0011]
Therefore, according to the first aspect of the present invention, the casing is rotated in the direction of the outer peripheral surface, and the casing is disposed at a position in contact with the outer peripheral surface. Therefore, the bead portion is difficult to contact even when the tire is attached / detached, and sudden impact is unlikely to be applied even at the time of contact. Furthermore, since one end abuts on the fixing means, the casing is hardly deformed by centrifugal force. Further, since the inclination angle with respect to the valve stem can be varied by the biasing means without any special work process, the attachment becomes easy.
[0012]
In the invention according to claim 2, an elastic member is provided as the urging means.
Therefore, according to the second aspect of the present invention, when the tire rotates and a centrifugal force that exceeds the elastic force of the elastic member acts on the casing, the casing rotates in a direction away from the outer peripheral surface. Move. As a result, the influence of the wheel 5 when the transmitter 3 wirelessly transmits measurement data to the receiver 4 is reduced.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the tire condition monitoring device includes four transmitters 3 provided on tire wheels (not shown) on which four tires 2 of the vehicle 1 are mounted, and 1 provided on the vehicle body of the vehicle 1. And four receivers 4. Each transmitter 3 measures the state of the corresponding tire 2, that is, the internal air pressure and the internal temperature, and wirelessly transmits data indicating the measured state to the receiver 4. The receiver 4 displays pressure information and temperature information on a display (not shown) provided in the passenger compartment based on the received data.
[0014]
As shown in FIGS. 3 and 4, each transmitter 3 includes a casing 10 disposed inside the tire 2 and a valve stem 11 attached to a valve hole 7 formed in the rim 5 a of the wheel 5.
[0015]
The casing 10 has a box shape, and is formed of a thermoplastic resin in the present embodiment. The casing 10 accommodates an electronic board 12 on which various electrical components such as a pressure sensor, a temperature sensor, a signal processing device, and a battery are mounted.
[0016]
The casing 10 is disposed on the inner side of the wheel 5 so that one surface thereof is along the drop center portion 5b which is a part of the outer peripheral surface of the wheel 5, and the surface on the drop center portion 5b side (the lower side in the figure). ) Is formed in contact with the drop center portion 5b. For the following description, the surface on the lid 13 side is the lower surface of the casing 10, and the opposite surface (the upper side in the figure) is the upper surface.
[0017]
The casing 10 has an opening on its lower surface, and the electronic substrate 12 is disposed in the casing 10 from the opening. The opening is closed by the lid 13.
[0018]
The valve stem 11 extends to the outside through the valve hole 7 formed in the wheel. A flange 21 is formed at the proximal end portion of the valve stem 11, and a grommet 22 is attached so as to be in close contact with the flange 21. In the present embodiment, rubber grommets 22 are used in order to improve adhesion.
[0019]
A valve nut 23 is detachably screwed to an intermediate portion in the axial direction of the valve stem 11. Further, a resin or metal valve cap 24 is detachably screwed to the tip of the valve stem 11. That is, with the valve cap 24 and the valve nut 23 removed, the valve stem 11 is inserted into the valve hole 7 from the inside of the wheel 5 of the rim 5a, and the valve nut 23 is screwed to the valve stem 11 from the outside of the wheel 5. By doing so, the valve stem 11 is attached to the valve hole 7 of the wheel 5.
[0020]
A flat surface 25 is formed at the inner end of the wheel 5 of the valve stem 11 on which the flange 21 is formed so as to be integrated with the flange 21. A vent hole 27 is formed at the center of the flat surface 25, and the vent hole 27 communicates with an air introduction hole 26 formed in the valve stem 11 along the axial direction. Although not particularly illustrated, a valve core is fitted in the air introduction hole 26, and air is injected into the tire 2 through the air introduction hole 26 and the air hole 27.
[0021]
The casing 10 and the valve stem 11 are connected to each other by a connecting portion 28 so that an angle between the casing 10 and the valve stem 11 is rotatable. The connecting portion 28 has a pair of connecting arms 29 formed on the upper surface of the casing 10, a connecting protrusion 30 of the pair of valve stems 11, and a rotating shaft 31.
[0022]
Each connecting arm 29 has a plate shape and is erected so as to be parallel to each other at the end of the upper surface of the casing 10 on the rim 5a side. Each connecting arm 29 extends from the end of the casing 10 on the rim 5a side so as to protrude toward the rim 5a. In addition, through holes 32 are formed near the ends of the connection arms 29 at positions facing each other.
[0023]
Each connection protrusion 30 has a plate shape and is erected at the end of the flat surface 25. Each connection protrusion 30 protrudes in the axial direction in parallel so as to face each other with the air hole 27 interposed therebetween. And the through-hole 33 is each formed in the position which opposes each other in the edge part vicinity of each connection protrusion 30. As shown in FIG.
[0024]
As shown in FIG. 2, the casing 10 has a through-hole 32 formed in the connection arm 29 and the connection protrusion 30 so that the connection protrusions 30 of the valve stem 11 are sandwiched between the pair of connection arms 29. And a pivot shaft 31 penetrating the through hole 33. That is, the casing 10 is connected to the valve stem 11 so as to be rotatable about the rotation shaft 31, and the inclination angle between the casing 10 and the valve stem 11 is such that the casing 10 rotates about the rotation shaft 31. It changes by moving.
[0025]
In the present embodiment, the distance between the connection arms 29 and the distance between the outer surfaces of the connection protrusions 30 are substantially the same, and both ends of the rotating shaft 31 are deformed into rivets by an external force. I am letting. Therefore, the casing 10 does not move in the direction parallel to the rotation shaft 31.
[0026]
The rotating shaft 31 is loosely fitted with a torsion coil spring 35 as an urging means and an elastic member. One end 35 a of the torsion coil spring 35 is in contact with the upper surface of the casing 10, and the other end 35 b is an end of the valve stem 11. It is in contact with the flat surface 25 of the part. As shown in FIGS. 3 and 4, the casing 10 is always urged toward the drop center portion 5 b by the elastic force of the torsion coil spring 35. As a result, the casing 10 is pressed by the one end 35a of the torsion coil spring 35, and the protrusion 10a is disposed at a position where it abuts against the drop center portion 5b.
[0027]
As described above, according to the present embodiment, the following operations and effects are achieved.
(1) The casing 10 is pivotally supported by a rotation shaft 31 that passes through a through hole 32 formed in each connection arm 29 and a through hole 33 formed in each connection protrusion 30 of the valve stem 11. did. As a result, the casing 10 rotates about the rotation shaft 31, and the inclination angle between the casing 10 and the valve stem 11 varies.
[0028]
As a result, even if the wheel 5 has a shape in which the drop center portion 5b and the rim 5a are substantially perpendicular to each other as shown in FIG. 3, the wheel has a shape in which the inclination of the rim 5a is large with respect to the drop center portion 5b as shown in FIG. Even in the case of 5, it is possible to easily secure an optimal mounting state.
[0029]
Specifically, as shown in FIG. 3, in the wheel 5 having the small formation angle θ <b> 1 of the valve hole 7, the casing 10 is rotated so as to reduce the inclination angle θ <b> 2 between the casing 10 and the valve stem 11. Further, as shown in FIG. 4, in the wheel 5 in which the formation angle θ <b> 3 of the valve hole 7 is large, the casing 10 is rotated so as to increase the inclination angle θ <b> 4 between the casing 10 and the valve stem 11. As described above, by varying the inclination angle between the casing 10 and the valve stem 11, it is possible to easily ensure an optimum mounting state at all times according to the shape of the wheel 5.
[0030]
(2) The torsion coil spring 35 is loosely fitted to the rotating shaft 31, one end 35 a of the torsion coil spring 35 abuts on the upper surface of the casing 10, and the other end 35 b is on the flat surface 25 at the end of the valve stem 11. It was decided to abut. The casing 10 is always urged toward the drop center portion 5b by the elastic force of the torsion coil spring 35. As a result, the casing 10 is pressed by the one end 35a of the torsion coil spring 35, and the protrusion 10a is disposed at a position where it abuts against the drop center portion 5b.
[0031]
As a result, even when the tire 2 is attached to and detached from the wheel 5, the bead portion of the tire 2 is unlikely to contact the casing 10. Further, even when the bead portion of the tire 2 comes into contact and the casing 10 is pressed toward the drop center portion 5b, the casing 10 and the drop center portion 5b are in contact with each other in advance, so that sudden impact is applied. Can be avoided. Furthermore, the casing 10 is disposed at a position where the projection 10a abuts against the drop center portion 5b without any special work process, so that an optimum mounting state can be easily secured.
[0032]
(3) Further, the casing 10 is pressed against the drop center portion 5 b by the elastic force of the torsion coil spring 35. As a result, when the tire 2 rotates and a centrifugal force exceeding the elastic force of the torsion coil spring 35 acts on the casing 10, the casing 10 moves away from the drop center portion 5 b and moves toward the rim 5 a. As a result, the influence of the wheel 5 when the transmitter 3 wirelessly transmits measurement data to the receiver 4 is reduced, and an optimal mounting state capable of ensuring a good communication state can be easily ensured. .
[0033]
In addition, you may change the said embodiment into the following aspects.
A temperature sensor may be provided in the transmitter 3 so that air pressure data and temperature data in the tire 2 are wirelessly transmitted from the transmitter 3 as data indicating the state of the tire.
[0034]
The vehicle is not limited to a four-wheeled vehicle, and the embodiment is applied to a two-wheeled bicycle or motorcycle, a multi-wheeled bus or a towed vehicle, or an industrial vehicle (for example, a forklift) equipped with tires. Also good. In addition, when applying the said embodiment to a towed vehicle, it cannot be overemphasized that the receiver 4 and a display are installed in a towed vehicle.
[0035]
In the present embodiment, both ends of the rotating shaft 31 are deformed into rivets by an external force. However, the present invention is not limited to this, and other methods such as nut fastening at both ends may be used.
[0036]
In the present embodiment, the urging force is applied by the torsion coil spring 35. However, the present invention is not limited to this, and another elastic member such as a leaf spring may be used.
Furthermore, the technical idea grasped | ascertained from the said embodiment is described below.
[0037]
(1) In the transmitter of the tire condition monitoring device according to claim 1 or 2, the casing and the valve stem include a connecting member having a through hole, and a rotating shaft that passes through the through hole. A transmitter of a tire condition monitoring device, wherein the casing is pivotally supported.
[0038]
(2) In the transmitter of the tire condition monitoring device according to (1), the elastic member is loosely fitted to the rotating shaft, and one end thereof abuts on the surface of the casing opposite to the outer peripheral surface, The transmitter of the tire condition monitoring device, wherein the other end is in contact with the valve stem.
[0039]
(3) In the transmitter of the tire condition monitoring device according to (1) or (2), the rotating shaft is deformed into rivets at both ends, and the casing is parallel to the rotating shaft. The transmitter of the tire condition monitoring device characterized by not moving.
[0040]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide a transmitter of a tire condition monitoring device that can easily ensure an optimum mounting condition.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a vehicle equipped with a tire condition monitoring device of the present embodiment.
FIG. 2 is a top view showing a structure of a transmitter. FIG. 3 is a side sectional view of the transmitter attached to a wheel.
FIG. 4 is a side sectional view showing the structure of a transmitter that is also mounted on a wheel.
FIG. 5 is a top view showing a structure of a conventional transmitter.
FIG. 6 is an explanatory diagram when a tire is mounted on a tire wheel.
[Explanation of symbols]
2 ... Tire, 3 ... Transmitter, 5 ... Wheel, 5b ... Drop center part, 10 ... Casing, 11 ... Valve stem, 28 ... Connection part, 29 ... Connection arm, 30 ... Connection protrusion, 31 ... Rotating shaft, 32, 33 ... through holes, 35 ... torsion coil springs.

Claims (2)

A casing that is disposed inside a tire mounted on a vehicle and houses various electrical components for measuring the state of the tire, and a valve stem that is attached to a wheel on which the tire is mounted, A transmitter of a tire condition monitoring device for transmitting data indicating:
The casing is connected to the valve stem so as to be rotatable in a direction substantially orthogonal to the outer peripheral surface of the wheel with the connecting portion as an axis,
Urging means for urging the casing toward the outer peripheral surface;
A transmitter for a tire condition monitoring device. In the transmitter of the tire condition monitoring device according to claim 1,
A transmitter of a tire condition monitoring device, comprising an elastic member as the biasing means.

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