JP2003025878A - Seat slide position detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive device capable of detecting a slide position of an upper rail as an absolute position at high reliability in a seat slide device for a vehicle. SOLUTION: A tilting plate 3 is fixed to a lower rail 1. A tilting surface 3A has a linear gradient. A sensor 4 for detecting a distance spaced from the tilting surface 3A is attached to the upper rail 2. The sensor 4 comprises a primary coil 42, a secondary coil 43, and a core 41, for example, and the tip of the core 41 is butted to the tilting surface 3A by an energizing force of a coil spring 46.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat position detecting device, and more particularly to a device for detecting a sliding position of a vehicle seat.

[0002]

2. Description of the Related Art Conventionally, various types of vehicle seat slide position detecting devices have been proposed. For example, Japanese Patent Laid-Open No. 61-71233 discloses a device which detects a slide position of a seat by an optical encoder attached to a motor shaft of a power seat. When the passenger gets in and out, the seat, which is once retracted to the last end where the micro switch is located, is automatically returned to the original sliding position after the passenger is seated. Japanese Unexamined Patent Publication No. 2-189241 discloses a device in which a slide position is detected by a potentiometer that is rotated in association with a motor shaft of a power seat. The power seat is driven by comparison with a separately installed potentiometer for indicating.

Japanese Unexamined Patent Publication No. 5-213142 discloses a sheet slide sensor for detecting a sheet position by short-circuiting a plurality of fixed pairs of contacts with a contact that moves together with the sheet. The position of the occupant's head is estimated from the sliding position of the seat, and the deployment condition level of the airbag is increased or decreased according to the estimated position of the head. US Pat. No. 6,053,529 discloses that
There is disclosed a seat position sensor that detects a seat position in three stages by detecting a staircase-like flange that moves with a seat and a staircase height of the flange by a fixed magnetic sensor. The magnetic sensor detects the seat slide position without contact and tries to send a position signal to a processor that deploys the airbag.

As described above, in the past, the seat slide position detecting device was used to drive the power seat to move the seat to a suitable position, but recently, to judge the deployment condition and deployment pressure of the airbag. The sheet slide position detection information is being requested from the slide position detecting device. For this reason, high reliability and high accuracy are required for the seat slide position detecting device.

[0005]

However, the slide position detecting device disclosed in Japanese Patent Laid-Open No. 61-71233 cannot detect the slide position as an absolute position after the power is turned off when the battery is replaced. This is because the optical encoder stores the relative position from the micro switch, not the absolute position, and thus there is a problem in that it is unreliable when used for airbag control. . Although the slide position detecting device disclosed in JP-A-2-189241 can detect the slide position as an absolute position as a rotational position of the potentiometer,
Since the potentiometer itself necessarily has a sliding contact structure between the slider and the resistor, there is a problem that it lacks reliability for long-term use. The slide position detecting device disclosed in Japanese Patent Laid-Open No. 5-213142 has a problem in that a large number of pairs of contacts must be provided, resulting in a complicated structure and an increase in cost. The slide position detecting device of US Pat. No. 6,053,529 has an excellent feature that it is non-contact and has a simple structure, but it has a problem that the slide position can be detected only in three steps.

Therefore, the present invention has such a high reliability that it can be used for controlling an airbag, can detect the absolute position of the seat slide position even after the power is turned off, and has a simple structure. The purpose is to provide.

[0007]

In order to achieve the above object, the first embodiment of the present invention has a lower rail 1 fixed to a vehicle body and a seat as shown in FIGS. 1 and 2. An upper rail 2 that is fixed, a holding structure (roller 6) that holds the upper rail 2 on the lower rail 1 so as to be movable in the longitudinal direction, and a gradient in the longitudinal direction that is fixed to either the lower rail 1 or the upper rail 2. And a sensor 4 fixed to either the lower rail 1 or the upper rail 2 for detecting the distance to the inclined surface 3A of the inclined plate 3, Characterize. Here, the sensor 4 may be a contact type or a non-contact type,
It refers to all the sensors that can detect the separation distance from the sensor 4 to the inclined surface 3A of the inclined plate 3.

When formed in this way, the upper rail 2
The distance between the sensor 4 and the inclined surface 3A of the inclined plate 3 uniquely changes depending on the position in the longitudinal direction (front-back direction of the sheet). Therefore, by detecting the distance by the sensor 4, the longitudinal position of the upper rail 2, that is, the slide position of the seat in the front-rear direction can be uniquely detected, that is, the absolute position of the slide position can be detected.

Here, as illustrated in FIG. 3 as a second embodiment of the present invention, a transformer (41, 4) provided with a core 41 in which the sensor 4 changes mutual inductance.
2, 43, 44) and has a biasing means 46 for biasing the tip portion (ball 45) of the core 41 so as to contact the inclined surface 3A of the inclined plate 3.

With this structure, since the core 41 is constantly pressed against the inclined surface 3A by the biasing means 46, the position of the core 41 is uniquely determined by the longitudinal position of the upper rail 2. The mutual inductance of the transformers (41, 42, 43, 44) changes depending on the position of the core 41, and the output voltage of the transformer changes. Therefore, the absolute position of the upper rail 2 can be detected by the output voltage of the transformer. That is, even if the vehicle-mounted battery is replaced, the output voltage does not change because it is at the absolute position. Here, the core 41, which is a movable portion, only contacts the bobbin 44 of the transformer, except that the tip portion (ball 45) contacts the inclined plate 3, and the coils 42 and 43, which are the heart of the detection, do not. Since it is a semi-contact type that does not contact, it has the effect of high durability and reliability for many years. Further, since the sensor 4 is the transformer (41, 42, 43, 44) only including the core 41, the structure is simple and the reliability is high.

Here, as illustrated in FIG. 6 as the third embodiment of the present invention, the sensor 4 is a differential transformer (71 to 74), and the tip portion of the core 71 of the differential transformer is the inclined portion. It can be characterized in that it has an urging means 46 for urging the plate 3 so as to come into contact with the inclined surface 3A of the plate 3. When formed in this way, in addition to the effect of the second embodiment, the linearity of the output signal with respect to the slide position of the upper rail 2 is improved as illustrated in FIG. 7, and the slide position signal by the processor (not shown) in the subsequent stage is improved. This has the effect of facilitating processing.

Here, as illustrated in FIGS. 3 and 4 as a fourth embodiment of the present invention, the transformers (41 to 4) are used.
4) or an electronic circuit (61-63) for exciting the differential transformer (71-74) and output voltage to the core 41,
The electronic circuit (64,
65) is incorporated in the sensor 4 (printed circuit board 60) and is integrally resin-molded (50). If formed in this way, the sensor body (41 to 44, 71 to 74) and the electronic circuit component (printed circuit board) 60 can be integrally molded (with the resin mold 50), and can be easily attached to the upper rail 2 or the lower rail 1. In addition to being able to do so, it is also resistant to vibrations and has a waterproof structure, so that the reliability as an on-vehicle component is enhanced.

Here, as a fifth embodiment of the present invention,
The sensor may be a magnetic sensor, and the tilt plate 3 may be made of a magnetic material. If, for example, a combination of a Hall element and a permanent magnet is used as the magnetic sensor, it is possible to detect the distance to the inclined plate 3 made of a magnetic material in a close position without any contact. There is an effect that a product excellent in durability and durability can be provided.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. 1 is a side view showing an upper rail 2 incorporated in a lower rail 1, and FIG. 2 is a sectional view taken along line XX of FIG. The lower rail 1 is a member fixed to the floor of the vehicle body. Multiple rollers 6 on the lower rail 1
The upper rail 2 is incorporated via the so as to be movable in the longitudinal direction. The upper rail 2 is a member to which a vehicle seat (not shown) is fixed, and the longitudinal direction means the front-back direction of the seat (not shown).

An inclined plate 3 is attached and fixed to the side surface of the lower rail 1 over the entire stroke (for example, 240 mm) of the upper rail 2. The inclined plate 3 is provided on the bottom surface of the lower rail 1 so that the lower rail 1
It is welded and fixed to. The inclined plate 3 is provided with a laterally extending portion of about 10 mm in width, and the upper surface of the extending portion forms the inclined surface 3A. Inclined surface 3A
As shown in FIG. 1, has a surface inclined at a constant angle with respect to the sliding direction of the upper rail 2, and is formed so that its height increases toward the rear. The height of the inclined surface 3A is detected to detect the slide position of the upper rail 2.

On the other hand, a sensor 4 for detecting the height of the inclined surface 3A is attached to the sliding upper rail 2. Referring also to FIG. 2, the bracket 5 is fastened to the member fixed to the upper rail 2 with a screw 81 and a nut. The sensor 4 is fastened to the bracket 5 with screws 82 and 83. The appearance of the sensor 4 is mainly made of a resin-molded member.

FIG. 3 shows the inside of the sensor 4, Y- in FIG.
It is a Y line sectional view. The sensor 4 is a transformer (41, 42, 4) including a core 41 that changes mutual inductance.
3,44) is the main element. The sensor 4 includes a cylindrical bobbin 44 having a center space, a primary coil 42 and a secondary coil 43 wound around the bobbin 44, and a core made of a magnetic material inserted in the center space of the bobbin 44. 41
A coil spring 46 (which constitutes an urging means) for urging the core 41 downward, a printed circuit board 60, a terminal 47 provided on the printed circuit board 60, a signal from the printed circuit board 60 and the like to the outside. A resin mold 5 is formed by molding with a resin using the terminal 48 to be drawn out as an element.
It is integrally molded as 0. The printed circuit board 60 includes an electronic circuit for exciting the primary coil 42 and the secondary coil 4.
An electronic circuit for converting the output of 3 into an electric signal is incorporated.

The resin mold 50 has a housing portion 51 which is open on one side, and the terminals 48 are exposed in the housing portion 51. There are three terminals 48. In addition, at the lower end of the cylindrical bobbin 44, the small-diameter portion 4 in which the center space is narrowed
4A is formed, and on the other hand, an enlarged large diameter portion 41A is formed at the upper end of the core 41. The small diameter portion 44A of the bobbin 44 and the large diameter portion 41A of the core 41 are engaged with each other so that the core 41 does not fall out of the center space of the bobbin 44. A ball 45 is rotatably held at the tip of the core 41 by caulking the tip. Ball 45 is core 4
1 constitutes the tip portion.

The core 41 and the coil spring 46 are assembled in the center space of the bobbin 44 as follows. First, the bobbin 44, the primary coil 42, the secondary coil 43, the printed board 60, the terminal 47, and the three terminals 48 are integrated by the resin mold 50. Then, the core 41 and then the coil spring 46 are inserted from above the center space of the bobbin 44. With these inserted, they are fastened to the plate-shaped bracket 5 from the bottom with mounting screws 82 and 83. Therefore, the upper portion of the coil spring 46 is pressed by the bracket 5 and compressed, and the core 41 is biased downward. In this state, the ball 45 rotatably held at the tip of the core 41 contacts the inclined surface 3A of the inclined plate 3.

FIG. 4 is a block diagram of an electronic circuit for driving a transformer (41, 42, 43) whose mutual inductance changes depending on the position of the core 41 and outputting an output signal. The electronic circuit 60 uses the battery voltage Vb of, for example, 5V.
Constant voltage circuit 61 for generating a constant voltage, an oscillation circuit 62 that oscillates at a stable frequency by receiving the voltage, an amplification circuit 63 that current-amplifies the oscillation signal to excite the primary coil, and an output waveform of the secondary coil 43 And a variable resistor 65 that adjusts the output voltage to generate the slide position detection signal Vs. The sensor 4 has three terminals 48, which are a battery voltage Vb input terminal, a slide position detection signal Vs output terminal, and a ground terminal.

The operation will be described based on the above configuration. When the upper rail 2 is slid to change the slide position of the seat, the position of the sensor 4 also moves accordingly, and the position at which the ball 45, which is the tip of the core 41, contacts the inclined surface 3A of the inclined plate 3 also changes. . When the upper rail 2 is near the foremost end, the inclined surface 3A is located at a lower position, so that the core 41 is pulled out from the bobbin 44 by the biasing force of the coil spring 46, and the primary coil 42 and the secondary coil Mutual inductance with 43 is reduced. As a result, even if the primary coil 42 is excited with the same current, the voltage induced in the secondary coil 43 becomes low, and the slide position detection signal Vs becomes low. On the contrary, when the upper rail 2 is near the rear end, the inclined surface 3A comes to a higher position, and the core 41 is pushed into the bobbin 44, and the primary coil 42 and the secondary coil 43 are in mutual contact. Inductance increases. As a result, even if the primary coil 42 is excited with the same current, the voltage induced in the secondary coil 43 becomes high and the slide position detection signal Vs becomes high.

FIG. 5 is a characteristic diagram showing the relationship between the slide position of the upper rail 2 and the slide position detection signal Vs. The characteristic is not linear because the movement amount of the core 41 and the variation amount of the mutual inductance are not linear. The variable resistor 65 is for finely adjusting an error due to variations in each element, variations in assembly accuracy, etc. so that the same slide position detection signal Vs voltage is output at the same slide position. It should be noted here that once the variable resistor 65 is finely adjusted, the characteristic of FIG. 5 is fixed, and even if the power source Vb is connected again after the battery is removed and Vb is dropped, the slide position detection is performed. That is, the voltage of the signal Vs does not change. That is, not the relative position of the upper rail 2 but the absolute position is continuously detected. Therefore, the absolute slide position of the upper rail 2 can be detected from the slide position detection signal Vs.

As described above, since the absolute position of the upper rail 2 can be detected with high reliability over the entire stroke, the occupant's body shape and head position are estimated from the slide position to optimize the airbag deployment conditions. This seat slide position detecting device can be applied to a system for controlling the above. Further, since the seating position of the occupant can be estimated, it can be applied to a device for automatically adjusting the vertical position of the steering wheel and the vertical and horizontal positions of the power door mirror to the optimum positions.

In the present embodiment, since the sensor 4 has the central core 41 and the two coils 42 and 43 as main elements, it has a simple structure, is inexpensive, and is highly reliable with no failure. There is an advantage that a seat slide position detecting device can be provided.

In the above embodiment, the secondary coil 43 is set to 1
Although two windings are used, the secondary coil may be divided into two windings to form a differential transformer. FIG. 6 is a circuit diagram showing a sensor 4 using a differential transformer. A predetermined excitation voltage Vex is applied to the primary coil 72 of the differential transformer. The secondary coil is divided into two windings 73 and 74, which are connected in series with their polarities reversed. A so-called differential voltage is output as the slide position detection signal Vs. Since it is a differential voltage, the output voltage Vs becomes linear corresponding to the moving amount of the core 71, and as shown in FIG. 7, the slide position detection signal Vs having a linear characteristic with respect to the position of the upper rail 2. Is obtained. Therefore, there is an advantage that processing by a processor (not shown) in the subsequent stage becomes easy.

In the above-described two embodiments, the transformers (41, 42, 43, 44) or the differential transformers (71, 72, 73, 74) are used as the sensor 4, and the cores 41, 71 of the center core are inclined. The sliding position of the upper rail 2 was detected by contacting it with the inclined surface 3A. But,
Distance from sensor to tilt plate 3 is 10 mm
In the following cases, the distance to the inclined plate 3 made of a magnetic material such as steel can be detected without contact by using a sensor in which a Hall element and a permanent magnet are combined. Since this form is completely contactless, it has the advantage of excellent reliability and durability.

In the embodiment described above, the inclined plate 3 is fixed to the lower rail 1 and the sensor 4 is attached to the upper rail 2, but the sensor 4 is attached to the lower rail 1 and the inclined plate 3 is fixed to the upper rail 2. May be. In this case, since the sensor 4 does not move, there is an advantage that wiring can be easily handled. Further, although the inclined surface 3A of the inclined plate 3 has a linear slope, depending on the purpose of use, the inclined surface 3A does not have a linear slope but a curved line having an appropriate output characteristic, or changes at only one place or a few places. It is also possible to use it as a switch shape for applications such as a switch. Further, in the case of using a transformer or a differential transformer, the inclined plate 3 may be made of a resin instead of a steel plate, and may be fixed to the lower rail by press fitting, fitting or screwing according to the shape of the lower rail.

[0028]

As described above, since the present invention detects the slide position of the upper rail by detecting the distance from the inclined surface of the inclined plate to the sensor, the absolute position of the upper rail is inexpensive and simple. It has an excellent effect that it can be detected with various structures and can be used for controlling the deployment condition of the airbag.

[Brief description of drawings]

FIG. 1 is a side view showing an upper rail incorporated in a lower rail.

FIG. 2 is a sectional view taken along line XX of FIG.

3 is a sectional view taken along line YY of FIG. 2 showing the inside of the sensor.

FIG. 4 is a block diagram of an electronic circuit that drives a transformer whose mutual inductance changes depending on the position of a core and outputs an output signal.

FIG. 5 is a characteristic diagram showing a relationship between a slide position of an upper rail and a slide position detection signal Vs.

FIG. 6 is a circuit diagram showing a sensor using a differential transformer.

FIG. 7 is a characteristic diagram showing a relationship between a slide position of an upper rail and a slide position detection signal Vs when a differential transformer is used.

[Explanation of symbols]

1 lower rail 2 Upper rail 3 Inclined plate 3A inclined surface 4 sensors 6 roller (holding structure) 41 core (transformer) 42 Primary coil (transformer) 43 Secondary coil (transformer) 44 Bobbin (Trance) 45 balls 46 Coil spring (biasing means) 50 resin mold 60 Printed circuit board (electronic circuit)

Claims (5)

[Claims] 1. A lower rail fixed to a vehicle body, an upper rail to which a seat is fixed, a holding structure for holding the upper rail movably in a longitudinal direction on the lower rail, and one of the lower rail and the upper rail. An inclined plate that is fixed and has an inclined surface that has a slope in the longitudinal direction, and a sensor that is fixed to either the lower rail or the upper rail and that detects the distance to the inclined surface of the inclined plate. Seat slide position detection device. 2. The transformer is a transformer having a core that changes mutual inductance, and has a biasing means that biases the tip end portion of the core so as to abut the inclined surface of the inclined plate. The seat slide position detecting device according to claim 1. 3. The sensor is a differential transformer, and has a biasing means for biasing the tip end portion of the core of the differential transformer so as to abut the inclined surface of the inclined plate. The seat slide position detecting device described in the above. 4. An electronic circuit for exciting the transformer or the differential transformer and an electronic circuit for outputting an output voltage as a position signal of the core are integrally incorporated in the sensor and resin-molded. The seat slide position detecting device according to claim 2 or 3. 5. The seat slide position detecting device according to claim 1, wherein the sensor is a magnetic sensor, and the inclined plate is formed of a magnetic material.