JP2003020833A - Structure of key cylinder for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of a key cylinder for a vehicle, which enables an increase in communication distance without upsizing a device. SOLUTION: In the key cylinder 10, a coil antenna 4, around which an electric wire is wound more than once, is provided near an end of a cylinder body 1; a rubber base 2 is arranged between the coil antenna 4 and the cylinder body 1; and a cap 5 is pressed on the side of the cylinder body 1 in such a manner that the coil antenna 4 is sandwiched from the end side of cylinder body 1, in order to be fixed to the cylinder body 1. Consequently, a degree of close contact of the antenna coil 4 is made higher to make inductance of the antenna coil 4 larger and enable the increase of the communication distance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a key cylinder structure when a coil antenna is arranged in a key cylinder of a vehicle and the electromagnetic induction action of the coil antenna is used to perform wireless communication with the key side.

[0002]

2. Description of the Related Art In recent years, an increasing number of vehicles are equipped with an immobilizer for the purpose of preventing theft of the vehicles. The immobilizer is configured to perform wireless communication between the vehicle side and the key side, and start the ignition when the IDs of the both sides match, and when the forged key is used, the ignition starts. Since it does not, theft can be prevented.

In such an immobilizer, data is transmitted and received between a coil antenna built in a key cylinder of a vehicle and a transponder built in the key side.

FIG. 7 is an explanatory view schematically showing a key cylinder portion and a key of a vehicle equipped with a conventional immobilizer, and as shown in FIG.
A shield plate 103 made of ferrite or the like is installed at the tip of the cylinder body 102, and a coil antenna 104 is arranged on the shield plate 103. An antenna cap 105 is arranged so as to cover the tip of the cylinder body 102.

The coil antenna 104 is constructed by winding an electric wire a plurality of times. When an electric signal is fed to the coil antenna, magnetic flux is generated as shown in S101 of the figure, so that the transponder 106a is incorporated. When the key 106 approaches, communication is established between the transponder 106a and the coil antenna 104. As a result, the IDs are collated, and if it is confirmed that the IDs match, the ignition is started when the key 106 is inserted into the key cylinder 101 and rotated.

If the IDs are not confirmed to coincide with each other, the ignition is not started even if the key 106 is operated. As a result, it is possible to prevent the vehicle from being stolen using the forged key.

However, in the immobilizer, in order to reliably operate at the actual use distance in consideration of variations and deterioration of products, it is desired to communicate at a longer distance, and in order to secure the ability of long distance communication. Needs to have a large inductance in order to increase the magnetic flux of the coil antenna 104. In the conventional key cylinder structure, in order to increase the inductance, the diameter of the coil antenna 104 (the diameter when wound in a circular shape) must be increased, and the number of windings of the winding must be increased. However, there is a problem in that the cost and the cost are increased.

On the other hand, in the conventional key cylinder structure, the coil antenna 10 mounted on the tip of the cylinder is used.
4, shield plate 103, and antenna cap 105
Form an integrated structure. That is, as shown in FIG. 8, an extremely thin electric wire is wound into a coil to form a coil antenna 104, and the coil antenna 104 is set in a mold and the tip portion 107 of the cylinder is integrated by insert molding. Is molded.

Therefore, stress due to the pressure and temperature of the resin during insert molding may be applied to the coil antenna 104, which may deform the coil antenna 104. In such a case, the coil antenna 104
There is a case where the inductance of is greatly deviated from the designed value, and in such a case, it cannot be used.

Further, the coil antenna 104 may be disconnected due to the injection pressure of the resin or the like. As a result, there is a problem that the yield is lowered and the reliability is also lowered.

[0011]

As described above, in the conventional vehicle key cylinder structure, when the inductance is large, the coil antenna 104 needs to be upsized, which increases the size and cost of the device. There was a problem of inviting. Further, in the configuration in which the tip portion of the key cylinder is integrated, the coil antenna 104 may be disconnected, which has a drawback that reliability is reduced.

The present invention has been made to solve such a conventional problem, and a first object thereof is to extend the communication distance by the coil antenna without increasing the size of the device. A key cylinder structure for a vehicle is provided. A second object is to provide a vehicle key cylinder structure that can improve the accuracy of the coil antenna when generating the key cylinder.

[0013]

In order to achieve the above object, the invention according to claim 1 of the present application is provided with a coil antenna, and wireless communication with the key side is performed by using the electromagnetic induction action of the coil antenna. In the structure of the possible key cylinder, the key cylinder is provided with a coil antenna in which an electric wire is wound a plurality of times near the tip of the cylinder body, and an elastic member is arranged between the coil antenna and the cylinder body. The cap member is fixed to the cylinder body by pressing the cap member toward the cylinder body from the tip side of the cylinder body with the coil antenna interposed therebetween.

The invention according to claim 2 is characterized in that a magnetic shield member is disposed between the elastic member and the coil antenna.

According to a third aspect of the present invention, the magnetic shield member has a flat plate ring shape, and the distance between the inner periphery of the magnetic shield member and the inner periphery of the coil antenna is
It is characterized in that it is larger than the distance between the outer periphery of the magnetic shield member and the outer periphery of the coil antenna.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view showing a key cylinder structure of a vehicle according to an embodiment of the present invention, and FIG. 2 is a sectional view showing the key cylinder structure. As shown,
The key cylinder 10 is a cylinder body 1 having a cylindrical shape.
A rubber pedestal (elastic member) 2 in the shape of a flat plate ring, which is provided at the tip of the cylinder body 1, and a shield plate (magnetic shield member) 3 also in the flat ring shape.
And a coil antenna 4 wound in a circular shape, a pedestal 2,
A shield plate 3 and a cap (cap member) 5 which covers the coil antenna 4 and is fixed to the cylinder body 1 are provided.

The pedestal 2 is provided with a bracket 2a on the peripheral portion thereof, and the bracket 2a has two bus bars 6 provided therein.
Is attached. The terminal portion 4a of the coil antenna 4 is wound around and electrically connected to the upper side of the bus bar 6 (the tip side of the key cylinder 10). On the other hand, the lower side of the bus bar 6 is connected to a signal processing circuit (not shown).

The cap 5 attaches the coil antenna 4, the shield plate 3, and the pedestal 2 to the cylinder body 1 with a desired pressing force.
It is fixed to the cylinder body 1 while being pressed to the side.

FIG. 3 is an explanatory view showing the configuration of the coil antenna 4 provided on the shield plate 3. As shown in FIG. 3, the coil antenna 4 has a substantially central portion of the shield plate 3 having a flat ring shape. Is located in. That is, the distance t1 between the inner periphery of the coil antenna 4 and the inner periphery of the shield plate 3,
The distance t2 between the outer periphery of the coil antenna 4 and the outer periphery of the shield plate 3 is set to be substantially equal.

By supplying an electric signal to the coil antenna 4 via the bus bar 6, a magnetic flux is generated and an electromagnetic induction action is performed to perform wireless communication with the key side equipped with the transponder. ing.

Next, the operation of the key cylinder structure according to this embodiment having the above-described structure will be described.

As shown in FIGS. 1 and 2, in the key cylinder 10 according to this embodiment, since the cap 5 is pressed against the cylinder body 1 side with a desired pressing force, the elasticity of the rubber base 2 is reduced. Due to the force, the coil antenna 4 wound a plurality of times is always in a state where a desired pressure is applied. As a result, the electric wire forming the coil antenna 4 is compressed, and the electric wires come into close contact with each other. As a result, the inductance of the coil antenna 4 can be increased, and the communication distance with the key side equipped with the transponder can be increased.

Further, the coil antenna 4 and the shield plate 3
Since the degree of close contact with is also increased, the magnetic flux spreading to the cylinder body 1 side can be suppressed, and as a result, the magnetic flux generated on the tip side of the key cylinder 10 can be increased.

FIG. 4 is an explanatory view schematically showing the spread of the magnetic flux output from the coil antenna 4. In FIG.
As compared with FIG. 7 shown in the conventional example, the elastic force of the rubber pedestal 2 increases the inductance of the coil antenna 4,
The reaching distance S1 of the magnetic flux is increased accordingly.

Next, a specific change in inductance will be described. In order to confirm the effect of the key cylinder structure according to the present embodiment, the inventors changed the a, b, and c portions of the tip end portion of the cylinder body 1 shown in FIG. Changes and communication distances were measured. The results are shown in Table 1 below.

[0026]

[Table 1] As shown in Table 1, in the first embodiment, the coil antenna 4 is installed in the portion a of FIG. 5 and the shield plate 3 is installed in the portion b (that is, the portion c is absent and the portion b is directly connected to the cylinder body 1). In the second embodiment, the coil antenna 4 is installed in the portion a, the shield plate 3 is installed in the portion b, and the rubber seat plate 2 is installed in the portion c.

Then, as shown in the first embodiment, when the rubber pedestal 2 is not used, the inductance of the coil antenna 4 is 987 μH (microhenry), while as shown in the second embodiment. When the rubber pedestal 2 is used, the inductance of the coil antenna 4 is
It became 1088 μH. Along with this, the communication distance is 38 mm in the first embodiment, while it is 4 mm in the second embodiment.
It became 6 mm. That is, it was confirmed that the communication distance can be extended by using the key cylinder structure according to the present embodiment.

As described above, in the key cylinder structure for a vehicle according to this embodiment, since the rubber pedestal 2 having elasticity is provided between the cylinder body 1 and the coil antenna 4, the coil antenna 4 is provided. The degree of close contact of the electric wires forming the device is increased, and as a result, the communication distance can be extended.

Further, the pedestal 2, the shield plate 3, the coil antenna 4, and the cap 5 have a separate structure, and the tip end portion of the key cylinder 10 is constituted by assembling them, so that the coil antenna 4 is Trouble such as disconnection can be avoided, yield can be improved, and reliability can be improved.

FIG. 6 is an explanatory view showing the configuration of a modified example of this embodiment, and shows the configuration of the coil antenna 4 installed on the shield plate 3. As shown in the figure, in the key cylinder structure according to the modified example, by using the shield plate 3 having the small diameter of the central opening, the distance t1 between the inner periphery of the coil antenna 4 and the inner periphery of the shield plate 3 is reduced. And the distance t2 between the outer periphery of the coil antenna 4 and the outer periphery of the shield plate 3 have a relationship of t1> t2.

With this configuration, the magnetic flux output from the coil antenna 4 can be further suppressed from spreading to the cylinder body 1 side, so that the inductance of the coil antenna 4 increases and The reaching distance of the magnetic flux to the tip side of the key cylinder 10 can be further increased.

A change in coil inductance based on experiments will be described below. Table 2 shows the relationship between the inner diameter, the outer diameter, and the thickness of the shield material 3 and the inductance of the coil antenna 4.

[0033]

[Table 2] As can be understood from Table 2, in Example 1, the inner diameter of the shield plate 3 was 18 mm, the outer diameter was 26 mm, and the thickness was 1 mm. In the second embodiment, the inner diameter of the shield plate 3 is 15 mm and the outer diameter is 26 mm. , And the thickness is 1 mm. Since the outer diameter of the shield plate 3 is the same in the first and second embodiments, the distance t1 between the inner periphery of the coil antenna 4 and the inner periphery of the shield plate 3 is the same as in the second embodiment. Is larger than the distance t2 between the outer periphery of the coil antenna 4 and the outer periphery of the shield plate 3. That is, t1> t2.

In the first embodiment, the coil antenna 4
The inductance was 891 μH, and in Example 2, this inductance was 930 μH. Therefore, by satisfying the condition of t1> t2, the inductance of the coil antenna 4 can be increased and the reaching distance of the magnetic flux can be increased.

The key cylinder structure for a vehicle according to the present invention has been described above based on the illustrated embodiment, but the present invention is not limited to this, and the configuration of each part is an arbitrary configuration having the same function. Can be replaced.

For example, in this embodiment, the example in which the rubber pedestal 2 is used as the elastic member has been described, but the present invention is not limited to this, and a flexible resin material or the like may be used. It is possible.

[0037]

As described above, in the vehicle key cylinder structure according to the present invention, the elastic member is arranged between the coil antenna and the cylinder body, and the biasing force of the elastic member causes the coil antenna to constantly compress the compressive force. Since the adhesion of the coil antenna is increased, the inductance of the coil antenna can be increased, and the communication distance of the coil antenna can be increased.

Further, by installing a magnetic shield member between the coil antenna and the cylinder body, it is possible to suppress the magnetic flux spreading to the cylinder body side and to extend the communication distance.

Furthermore, by increasing the distance between the inner periphery of the magnetic shield member and the inner periphery of the coil antenna, the communication distance can be further expanded.

Further, since the elastic member, the magnetic shield member, the coil antenna, and the cap member mounted on the cylinder body are separately structured, troubles such as disconnection of the coil as in the conventional case can be avoided. Therefore, the reliability can be improved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a key cylinder structure of a vehicle according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a key cylinder structure of a vehicle according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an arrangement of coil antennas provided on a shield plate.

FIG. 4 is an explanatory diagram schematically showing a reaching distance of a magnetic flux output from a coil antenna.

FIG. 5 is an explanatory diagram showing a configuration of a tip portion of a key cylinder when measuring a change in inductance.

FIG. 6 is an explanatory diagram showing a positional relationship between a shield plate and a coil antenna according to a modified example.

FIG. 7 is an explanatory diagram schematically showing a reaching distance of a magnetic flux from a coil antenna in a conventional key cylinder structure.

FIG. 8 is an explanatory diagram showing a configuration of a key cylinder tip portion in a conventional key cylinder structure.

[Explanation of symbols]

1 cylinder body 2 Rubber base (elastic member) 3 Shield plate (shield member) 2a bracket 4 coil antenna 4a end part 5 Cap (cap member) 6 bus bars 10 key cylinder

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Claims (3)

[Claims] 1. A structure of a key cylinder in which a coil antenna is provided, and wireless communication with a key side is enabled by using an electromagnetic induction action of the coil antenna, wherein the key cylinder is in the vicinity of a tip end portion of a cylinder body. In addition to providing a coil antenna in which an electric wire is wound a plurality of times, an elastic member is arranged between the coil antenna and the cylinder body, and a cap member is sandwiched between the coil antenna from the tip side of the cylinder body, A key cylinder structure for a vehicle, characterized in that the cap member is pressed to the cylinder body side and the cap member is fixed to the cylinder body. 2. The key cylinder structure for a vehicle according to claim 1, wherein a magnetic shield member is arranged between the elastic member and the coil antenna. 3. The magnetic shield member has a flat plate ring shape, and the distance between the inner periphery of the magnetic shield member and the inner periphery of the coil antenna is between the outer periphery of the magnetic shield member and the outer periphery of the coil antenna. The key cylinder structure for a vehicle according to claim 2, wherein the key cylinder structure is larger than the interval.