JPS605488Y2 - tire pressure sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tire air pressure sensor that is attached to an air valve of a tire in order to detect when the air pressure of the tire exceeds a predetermined allowable range value.

The tire pressure sensor according to the present invention is suitable for forming a tire pressure warning device together with a dry battery and a buzzer arranged in the center of a road wheel of a tire, and is used to notify when the tire pressure has decreased below a predetermined value. It is installed to detect an abnormal drop in tire air pressure and automatically activate a buzzer to alert you of an abnormal drop in tire air pressure.

However, in the conventional tire pressure sensor of this type, the structure of the sensor section that operates as a switch when there is an abnormal change in the tire pressure has been complicated.

That is, in the sensor section of a conventional tire pressure sensor that has a normally open switch mechanism that is turned on when the tire air pressure abnormally decreases, the fixed contact of the normally open switch mechanism is constructed from a bent contact plate. Therefore, disposing the contact plate in a relatively small tire air pressure sensor results in a complicated configuration of the sensor section.

Furthermore, when a plurality of fixed contacts are provided, the respective contact plates must be placed slightly apart from each other, and it is troublesome to solder lead wires to the respective distributed contact plates.

The complicated structure of the sensor section as described above has been an obstacle in reducing the size of the tire air pressure sensor.

In addition, with conventional tire pressure sensors, when the sensor section is switched on due to an abnormal change in tire pressure,
The switch state is maintained until the tire air pressure is corrected, and as a result, the buzzer in the tire air pressure warning device is activated more than necessary, and for example, when parking, the buzzer sound causes noise pollution to the surrounding environment. There was fear.

The present invention has been devised to eliminate the various drawbacks of the above-mentioned conventional technology, and provides a compact tire pressure sensor with a simple configuration by printing and molding the fixed contacts in the sensor section on a printed circuit board. With the goal.

In addition, the present invention has the fixed contacts in the sensor part and the fixed contacts related to operation check printed on the same surface of the printed circuit board, so that the switch of the sensor part that is activated due to an abnormal change in tire air pressure can be released at will. Another object of the present invention is to provide a tire air pressure sensor having a simple configuration and an operation check function.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Reference numeral 1 denotes a main body, and a ring nut 3 is rotatably provided on one circumference via a wire ring 2. By screwing the ring nut 3 into an outer cylinder 4a of an air valve 4 of a tire, the main body 1 can be rotated. It is attached to the air valve 4.

During this installation, the center protrusion 1a of the main body 1 presses the tip of the valve body 4C penetrated by the valve core 4b of the air valve 4 to keep the air valve 4 open, so that the main body 1 The tire air pressure is introduced through the notch 1b provided at the tip of the tire and the center opening IC.

Reference numeral 5 denotes a rubber seal, which is interposed at the abutting portion between the main body 1 and the outer cylinder 4a to prevent tire air pressure from leaking.

The rubber seal 5 has its dimensions so that the center protrusion 1a comes into contact with the outer cylinder 4a before the air valve 4 is opened when the ring nut 3 is screwed, and the tire air pressure does not leak when the main body 1 is installed. Set.

Further, the insulating cylinder 6 is fixed to the main body 1 by bending the peripheral edge 1e from which the cord insertion portion 1d has been removed, and crimping the flange 6a at one end with the peripheral edge 1e.

Further, a rubber tire flam 7 and a printed circuit board 8 are sandwiched between the main body 1 and the cylinder 6.

The rubber diaphragm 7 is compression-fitted into the stepped opening 1f of the main body 1 and airtightly isolates the interior of the main body 1 and the cylindrical body 6 by a packing action.
is fitted into the stepped opening 1g of the main body 1 and held within the container of the cylindrical body 6.

Reference numeral 9 denotes a conductive hollow shaft, which can freely move forward and backward into the cylinder body 6.
It is arranged so as to be rotatable within a range of 0°, and a knob 11 is fixed thereto via a bushing nut 10 press-fitted into one end thereof.

The forward and backward movement of the hollow shaft 9 is regulated by the shoulder 9a and the shoulder 6b of the cylinder 6, and the rotation of the hollow shaft 9 is restricted by the shoulder 9a of the hollow shaft 9 and the shoulder 6b of the cylinder 6. The rotation range is restricted to 90° by stoppers 9b and 6c arranged opposite to 6b.

Reference numeral 12 denotes an adjustment screw screwed onto the cylindrical body 6, which presses the movable element 13, which engages with the hollow shaft 9 in the rotational direction, against the printed circuit board 8 via a spring 14. The height is set by adjusting the screw position of the adjustment screw 12.

The movable element 13 is fitted into the other groove 9c of the hollow shaft 9 so as to move forward and backward.
is engaged in.

The contact portions 13a and 13b of the movable element 13 are brought into pressure contact with the upper surface of the printed circuit board 8 by the elastic force of the spring 14, and the protruding portion 13c at the center penetrates the through hole 8a of the printed circuit board 8 and It is in pressure contact with the diaphragm 7.

Further, the shoulder 9a of the hollow shaft 9 is pressed against the shoulder 6b of the cylinder 6 due to the repulsive force of the spring 14, and the groove 9c of the hollow shaft 9 is pressed against the shoulder 6b of the cylinder 6.
The bottom surface portion 9d of the movable member 13 is elastically separated by a gap A.

Reference numeral 15 denotes a check contact plate, which is fitted into the cut groove 9e at the other end of the hollow shaft 9 and then fixed with solder.

In the checking contact plate 15, the gap A is eliminated by pushing the knob 11 in the direction of the arrow B in FIG.
The bottom surface 9d of the groove 9c of the hollow shaft 9 is formed so as to come into pressure contact with the upper surface of the printed circuit board 8 when it comes into contact with the movable element 13.

The contact portion 13 of the movable element 13 is located on the upper surface of the printed circuit board 8.
Fixed contacts 8b and 8c corresponding to a and 13b and a fixed contact 8d corresponding to the check contact plate 15 are printed, and the fixed contacts 8b, 8c and 8 are printed.
The wiring portion d is located in the cord insertion portion 1d of the main body 1, and lead wires 16, 17, and 18 are soldered to each wiring portion.

The fixed contacts 8b and 8c are printed to face the contact portions 13a and 13b when the mover 13 is at the limit position for clockwise rotation, and the fixed contact 8d is printed when the mover 13 is at the limit position for right rotation. It is printed and molded to face the check contact plate 15 when it is at the limit position for clockwise rotation as shown in FIG.

Reference numeral 19 denotes a rubber ring with an X-shaped cross section, which is fitted into the outer peripheral groove 6d of the cylinder 6 so as to be compressed between the outer periphery of the cylinder 6 and the opposing portion of the knob 11, and prevents water from entering from the outside. It is preferable to fill the knob 11 with grease or the like to ensure smooth rotation of the knob 11.

Reference numeral 20 denotes a sleeve-shaped rubber cover, one end of which is tied tightly to the outer periphery of the main body 1 by a band 21, and an inner peripheral protrusion 20a of the other end slidably fits into the groove 11a of the knob 11. , is fitted between the main body 1 and the knob 11.

The fitting portion of the groove 11a of the knob 11 is preferably filled with grease or the like in order to prevent water from entering from the outside and to smoothen the rotation of the knob 11.

Also, as shown in FIG. 4, a rubber cover 2 near the knob 11 is
For example, a triangular mark 20b is attached to the end of the knob 11.
A mark 11b for ON indication and a mark 20b for OFF indication are arranged on the outer end surface of , being offset by 90' in the circumferential direction.

The mark 11b for the ON display is opposite the triangular mark 20b when the knob 11 is at the limit position for clockwise rotation, and the mark 11c for the OFF display is a triangle when the knob 11 is at the limit position for counterclockwise rotation. It is located opposite the object 20b.

The tire air pressure sensor according to the present invention is connected to a tire air pressure alarm device via the lead wires 16, 17, and 18, for example, as shown in FIG.

22 is a dry battery, 23 is a rotation detection switch provided on a road wheel, etc., 24 is an alarm buzzer, 25 is a transistor,
26 is an oscillation circuit such as an astable multivibrator, 27 and 28 are resistors, and 29 is a capacitor.

In the above configuration, the tire air pressure sensor according to the present invention has the following features:
The tire pressure warning device operates as follows.

Normally, the knob 11 is set to the limit position for clockwise rotation, and the ON display mark 11b is placed on the rubber cover 20 as shown in FIG.
20b facing the triangular mark 20b.

At this time, the contact portions 13a and 13b of the movable element 13 are provided opposite to the fixed contacts 8b and 8c, and the check contact plate 15
is arranged opposite to the fixed contact 8d.

As mentioned above, when the tire pressure sensor is in the normal use state, when normal tire pressure is introduced into the chamber 1h of the main body 1, the center portion of the rubber tire flamm 7 is moved by the spring 14.
The mover 13 is pushed and displaced toward the right in FIG.
The contact portions 13a and 13b are separated from the fixed contacts 8b and 8c, and the check contact plate 15 is also separated from the fixed contact 8d.

Therefore, the tire pressure warning device shown in FIG. 5 is not activated, and the vehicle driver knows that the tire pressure is normal.

Next, when the tire pressure sensor is in normal use,
When the tire air pressure decreases below the specified value, the center portion of the rubber tire flamm 7 is reversed by the spring 14 and becomes the state shown in FIG.
3b is in pressure contact with the fixed contacts 8b and 8c, and the fixed contacts 8b
and the fixed contact 8c are electrically connected.

At this time, if the vehicle is running, the tire pressure warning device shown in FIG. 5 issues a warning with a buzzer sound, and if the vehicle is stopped, it does not issue the above-mentioned warning.

That is, when the vehicle is running as in the former case, the rotation detection switch 23 is closed, and the positive terminal of the oscillation circuit 26 is connected via the resistor 27, the rotation detection switch 23, the fixed contact 8c, the movable element 13, and the fixed contact 8b. The positive terminal of the buzzer 24 is connected to the positive terminal of the dry battery 22 via the fixed contact 8c, the movable element 13, and the fixed contact 8b. The oscillation output is outputted to the base of the transistor 25, and the transistor 25 is turned on and off to cause the buzzer 24 to sound intermittently.

Therefore, the operation of the buzzer 24 allows the vehicle driver to know that there is an abnormality in the tire air pressure.

Further, when the vehicle is stopped as in the latter case, the rotation detection switch 23 is open, and the positive terminals of the oscillation circuit 26 and the buzzer 24 are not connected to the positive terminal of the dry cell battery 22, and the buzzer 24 is not connected to the positive terminal of the dry battery 22.
is not activated.

Therefore, the dry battery 22 is prevented from being completely exhausted due to the buzzer 24 continuing to sound due to a decrease in tire air pressure during parking.

Next, after the driver becomes aware of the decrease in tire pressure due to the activation of the buzzer 24, the rotation detection switch 23 remains on while the driver stops the vehicle, gets out of the vehicle, and confirms which wheel's tire pressure has decreased. When turned off, resistor 28 and capacitor 29
The delay circuit consisting of
Since the oscillation circuit 26 continues to operate and the buzzer 24 sounds, the above confirmation can be performed during this time.

After that, if the driver is unable to immediately replenish the tire pressure for the specified wheel, the driver should turn knob 11 to the left 9
By rotating 0', the contact portion 13a of the movable element 13
and 13b can be separated from the fixed contacts 8C and 8d to stop the operation of the tire pressure warning device.

That is, by moving the knob 11 from the limit position for clockwise rotation to the limit position for counterclockwise rotation, the contact portion 8 of the movable element 8
This is because the upper surface of the printed circuit board 8 is moved to a position where C and 8d cannot come into contact with the sliding waist fixed contacts 8C and 8d, and at this time, the OFF display mark 11c on the knob 11
faces the triangular mark 20b.

Next, when checking whether the circuit and various elements of the tire pressure alarm device are normal or not, when the tire pressure sensor is in normal use, turn knob 11 to spring 1.
4 in the direction of the arrow B in FIG. Regardless of whether the rotation detection switch 23 is open or closed, the tire pressure alarm circuit is arbitrarily closed, and if there is an abnormality, the buzzer 24 does not sound, so that the vehicle driver can be informed of the abnormality.

Note that the present invention is not limited to the structure of the above-described embodiment, and can be modified in various ways. For example, instead of the check contact plate 15, a protrusion may be integrally formed from the hollow shaft 9 on the movable member 13.
The protrusion may be formed at a position facing the fixed contact 8d at the limit position for clockwise rotation, and this protrusion may be used as a contact point.

The tire air pressure sensor according to the present invention has the above-mentioned configuration and operation, and has the following effects.

By printing and molding the fixed contacts on the printed circuit board, the contact mechanism can be simplified, and the assembly process of the tire air pressure sensor can be simplified.

Furthermore, by print-molding the fixed contacts on a single printed circuit board, the contact mechanism can be configured in a compact size, and as a result, a compact tire air pressure sensor can be provided.

In addition, by intensively printing the lead wire connection parts of multiple printed fixed contacts,
The lead wires can be uniformly connected to each fixed contact, and the assembly productivity of the tire air pressure sensor is improved.

In addition, in order to make the movable element rotatable at a position on the printed circuit board that cannot contact the printed fixed contact, a knob that engages the movable element in the rotational direction is provided. The switch of the activated sensor section can be released at will, and the tire pressure warning device will stop unnecessary warnings of abnormal tire pressure by buzzer sounds, etc., and avoid causing noise pollution to the surrounding environment. be able to.

Further, by stopping the tire pressure warning device from continuing to issue unnecessary warnings, it is possible to prevent the power supply from being exhausted.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a tire air pressure sensor according to the present invention;
Fig. 2 is an exploded perspective view of the tire air pressure sensor according to the present invention, Fig. 3 is a cross-sectional view taken along arrow C-C in Fig. 1, Fig. 4 is a view taken along arrow D in Fig. 1, and Fig. 5 is a main view. FIG. 2 is an electrical circuit diagram of a tire pressure warning device using the tire pressure sensor according to the invention. 1...Body, 7...Rubber diaphragm, 8...Printed circuit board, 8bt 8ct a
a...Fixed contact, 13...Movable element, 1
1...Pick.

Claims (1)

[Scope of utility model registration request] A main body attached to a tire air valve via a ring nut on one side, an insulating cylinder fixed to the other side of the main body, a diaphragm and a print sandwiched between the cylinder and the main body. a hollow shaft inserted into the cylindrical body so as to be movable forward and backward and rotatable within a predetermined angle, and having a knob fixed to one end and a check contact fixed to the other end; It has a protruding part that penetrates the through hole and presses the diaphragm, and a contact part that presses against the upper surface of the printed circuit board, and is rotated by the hollow shaft so that the contact part can be rotated to the switch operating position. A movable element is elastically disposed in a groove bored at the other end of the hollow shaft via a spring, and the movable element is moved by displacement of the diaphragm due to tire air pressure or by pressing or rotating the knob. A tire air pressure sensor comprising a contact portion of a movable element and a fixed contact disposed on the same surface of the printed circuit board that comes into contact with and separates from the check contact.