JP5195124B2 - Trigger machine mounting structure in tire pressure detector - Google Patents

Description

  In the present invention, a trigger signal output from a trigger machine is received by a transmitter / receiver attached to each wheel, and in synchronization with this, tire pressure detection is performed by sending information on tire pressure from the transmitter / receiver to a receiver on the vehicle body side. The present invention relates to a trigger machine mounting structure in a tire pressure detecting device.

  Conventionally, there is a direct type as one of tire pressure detecting devices. In this type of tire air pressure detection device, a transmitter / receiver equipped with a sensor such as a pressure sensor is directly attached to a wheel side to which a tire is attached. Also, an antenna and a receiver are provided on the vehicle body side, and when a detection signal from the sensor is transmitted from the transceiver, the detection signal is received by the receiver via the antenna, and tire pressure is detected. To be done.

  In such a direct type tire pressure detecting device, a trigger machine (antenna) for outputting a trigger signal is provided on the vehicle body side, and by outputting the trigger signal from the trigger machine, information on the tire pressure is transmitted from the transceiver. It is output. In addition, the trigger signal output from the trigger device is detected by the transmitter / receiver, and the trigger signal received by each transmitter / receiver is attenuated as the signal strength of the trigger signal decreases as the distance from the trigger device increases. Based on the received intensity, wheel position detection is performed to determine which wheel each transceiver is attached to (see, for example, Patent Document 1).

  The trigger machine used in this way is conventionally fixed to a surface parallel to the vehicle width direction on the inner wall surface of the tire house. And a trigger machine is arrange | positioned so as to oppose the surface parallel to a vehicle width direction among the inner wall surfaces of a tire house so that a trigger signal may be transmitted with respect to the transmitter / receiver which wants to receive a trigger signal.

As the trigger machine, one that can control the directivity of the trigger signal so that the target signal is received by the target machine among the transceivers of the own vehicle and is not received by the non-target machine or the transceiver of the other vehicle is used. It is preferred that As an antenna shape capable of controlling such directivity, for example, a structure shown in Patent Document 2 has been proposed. Specifically, in the magnetic sensor type antenna wound around the magnetic core made of a magnetic material, the end of the magnetic core collecting the magnetic flux is bent in a direction in which a desired directivity can be obtained.
JP 2007-15491 A JP 2006-50552 A

  However, when the mounting structure is such that the trigger machine is fixed to a surface parallel to the vehicle width direction of the inner wall surface of the tire house as in the prior art, the trigger machine is arranged to protrude from the inner wall surface of the tire house. Will be. For this reason, the tire house must have a structure that allows for the dimensions of the trigger machine, such as a dimension that takes into account the mounting space of the trigger machine. In particular, as shown in Patent Document 2, if the magnetic core is bent in a direction in which directivity can be obtained, the height of the trigger machine in the radial direction of the magnetic axis increases, so the dimensions of the trigger machine are larger. Become.

  In view of the above, the present invention has as its first object to provide a trigger mounting structure that does not require consideration of the trigger mounting space in the structure of the tire house.

  It is also a second object of the present invention to provide a mounting structure for a trigger machine that does not require consideration of the mounting space for the trigger machine in the structure of the tire house and that can obtain a desired directivity without bending the magnetic core. The purpose.

  In order to achieve the above object, according to the first aspect of the present invention, when the trigger machine (5) configured by the magnetic field antenna is installed in the tire house (10) where the plurality of wheels (6a to 6d) are arranged. The tire house (10) is provided with a storage window (10b) in which a part of the wall surface (10a) of the tire house (10) is opened, and the interior of the storage window (10b) A housing (11) made of a magnetic material that constitutes a space and has an opening on one side is provided, and in the internal space formed by the housing (11), the axial direction of the core (8) is the vehicle width direction. A trigger machine (5) is arrange | positioned so that it may become parallel. Further, the dimension (L1) from the center of the core (8) to the inner wall surface of the housing (11) in the axial direction of the core (8) is 1.1 times the axial dimension (Lw) of the core (8). (1.1Lw) or more, and in the radial direction centered on the axis of the core (8), on the line connected to the inner wall surface of the casing (11) passing through the central axis of the core (8) at the shortest distance The dimensions (L2, L3) from the side surface of the core (8) to the inner wall surface of the housing (11) are 1.5 times (1.5Lh, 1.5Ld) the dimensions (Lh, Ld) of the core (8). As described above, the trigger machine (5) is arranged.

  As described above, the storage window (10b) is provided in the tire house (10), the housing (11) is disposed in the storage window (10b), and the trigger machine (5) is provided in the housing (11). I am trying to install. For this reason, it is not necessary to make the inside of a tire house (10) into the dimension which considered the mounting space of a trigger machine (5). Accordingly, the structure inside the tire house (10) can be a trigger machine (5) mounting structure that does not require consideration of the mounting space of the trigger machine (5). And since each dimension (L1-L3) from a trigger machine (5) to the inner wall face of a housing | casing (11) becomes the said dimension, it is the trigger signal of the influence by the influence of the inner wall surface of a housing | casing (11). It can prevent that magnetic intensity falls.

  In the second aspect of the present invention, a part of the opening of the housing (11) is covered with the lid (12) made of a magnetic material, and the directivity of the trigger signal output from the trigger machine (5). Is shifted with respect to directivity when in free space.

  Thus, the directivity of the trigger signal of the trigger machine (5) can be controlled by forming a structure in which a part of the housing (11) is covered with the lid (12) made of a magnetic material. . For this reason, it becomes possible to obtain desired directivity without bending the core (8). Accordingly, the height in the radial direction with respect to the axis of the core (8) can be reduced as compared with the case where the core (8) is bent, and the size of the trigger machine (5) does not have to be increased. Thereby, it is not necessary to consider the mounting space of the trigger machine (5) in the structure in the tire house (10), and the trigger can obtain desired directivity without bending the core (8). It becomes possible to make the mounting structure of the machine (5).

  For example, as described in claim 3, the internal space of the housing (11) is a rectangular parallelepiped composed of sides parallel to the vehicle width direction, the vehicle height direction, and the vehicle front-rear direction, and the lid body. (12) can be a triangle that covers a region including the lower corner of the opening outside the vehicle (1).

  In this way, the cover (12) covers the region including the lower corner on the outside of the vehicle in the opening of the housing (11), so that the position where the magnetic strength on the outside of the vehicle is weakened on the upper side. Moved to. Thereby, it can suppress that a trigger signal is received with the transmitter / receiver of an adjacent vehicle, and it becomes possible to suppress malfunctioning of the transmitter / receiver by the trigger signal of another vehicle.

  In the invention according to claim 4, the ratio (S ′) of the area (S ′) of the region not covered with the lid (12) of the opening to the area (S) of the opening of the housing (11). '/ S) is 25% or more.

  Thus, the ratio (S ′ / S) of the area (S ′) of the region not covered with the lid (12) of the opening to the area (S) of the opening of the housing (11) is obtained. If it is 25% or more, the ratio (S ′ / S) is 100%, that is, the maximum magnetic field strength is reduced by 6 dB or less compared to when the opening of the housing (11) is not covered at all by the lid (12). It becomes. For this reason, sufficient magnetic field strength can be obtained.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an overall configuration of a tire air pressure detection device that also functions as a wheel position detection device to which an embodiment of the present invention is applied. The upper direction in the drawing of FIG. 1 corresponds to the front of the vehicle 1, and the lower direction of the drawing corresponds to the rear of the vehicle 1. With reference to this figure, the tire pressure detecting device in the present embodiment will be described.

  As shown in FIG. 1, the tire air pressure detection device is attached to a vehicle 1 and includes a transceiver 2, a receiver 3, a display device 4, and a trigger device 5.

  The transceiver 2 is attached to each of the four wheels 6a to 6d in the vehicle 1. The transceiver 2 measures the reception intensity of the trigger signal output from the trigger machine 5, and the tire pressures attached to the wheels 6a to 6d. After detecting and storing the received intensity data indicating the detection result and the data related to the tire pressure in the same frame or in another frame together with its own ID information, it is transmitted as, for example, an RF band signal.

  The receiver 3 is attached to the vehicle body 7 side of the vehicle 1 and receives a frame transmitted from the transceiver 2 to perform wheel position detection and tire air pressure detection processing. That is, the receiver 3 includes a control unit, and in accordance with a program stored in advance in the control unit, sends a trigger command signal that instructs the trigger device 5 to transmit a trigger signal, or responds to the trigger signal. The reception intensity data of the trigger signal is read out from the frame sent from each transceiver 2 and the transceiver 2 that has transmitted each frame is attached to any of the wheels 6a to 6d based on the magnitude of the reception intensity. The wheel position is detected to determine whether the vehicle is

  Further, the control unit of the receiver 3 identifies the wheels 6a to 6d to which the transceiver 2 is attached by detecting the wheel position, and then stores the ID information of each transceiver 2 stored in the frame transmitted from the transceiver 2. The tire pressures of the wheels 6a to 6d are obtained by performing various processes and calculations based on the tire pressure data stored in the frame while identifying the wheels. And the electric signal according to the calculated | required tire pressure is output to the indicator 4. FIG. For example, the control unit compares the obtained tire air pressure with a predetermined threshold value Th, and outputs a signal to that effect to the display 4 when it is detected that the tire air pressure has decreased. Thereby, the indicator 4 is informed that the tire pressure of any of the four wheels 6a to 6d has decreased.

  As shown in FIG. 1, the display 4 is arranged at a place where the driver can visually recognize, and is configured by an alarm lamp installed in an instrument panel in the vehicle 1, for example. For example, when a signal indicating that the tire air pressure has decreased is sent from the control unit of the receiver 3, the display 4 notifies the driver of the decrease in the tire air pressure by displaying that effect.

  When the trigger command signal sent from the control unit of the receiver 3 is input, the trigger machine 5 outputs a trigger signal having a predetermined signal strength, for example, in the LF band of 125 to 135 kHz. FIG. 2 is a schematic enlarged view showing the structure of the trigger machine 5. As shown in this figure, the trigger device 5 is an antenna for an LF band communication device configured by a coil-shaped magnetic field antenna in which a coil 9 is wound around a core (magnetic core) 8, for example. A magnetic field serving as a trigger signal is generated by passing a current through 9, and the trigger signal is transmitted to the receiver 3 by propagating this magnetic field. As such a magnetic field type antenna, for example, Toko Co., Ltd., core size: 10 mm × 10 mm × 50 mm, core material: ML24D, and coil winding number 18 turns can be used. The trigger machine 5 is attached to the vehicle body 7 so that the central axes of the core 8 and the coil 9 are parallel to the vehicle width direction (the vehicle left-right direction).

  The trigger machine 5 includes two units: a first trigger machine 5a arranged on the front wheel side and a second trigger machine 5b arranged on the rear wheel side. Each trigger machine 5a, 5b is arranged offset with respect to a center line that divides the vehicle 1 symmetrically so as to be at a different distance from the transmitter / receiver 2 attached to each wheel that is to receive the trigger signal. . In the case of the present embodiment, the first trigger machine 5a transmits a trigger signal using the transceiver 2 attached to the left and right front wheels 6a and 6b as a target machine, and the two trigger machine 5b is a transceiver attached to the left and right rear wheels 6c and 6d. The trigger signal is transmitted with 2 as the target machine.

  Specifically, in the present embodiment, the first trigger machine 5a is arranged in the vicinity of the left front wheel 6b, and the second trigger machine 5b is arranged in the vicinity of the left rear wheel 6d. Located on the left side. Therefore, the distance from the first trigger machine 5a to the right front wheel 6a is longer than the distance from the first trigger machine 5a to the left front wheel 6b, and the distance from the second trigger machine 5b to the right rear wheel 6c. However, it is longer than the distance from the second trigger machine 5b to the left rear wheel 6d.

  The first and second trigger machines 5a and 5b are mounted at predetermined locations in the tire house (in the liner). The first and second trigger machines 5a and 5b can be fixed in the tire house by various methods, for example, through a stay.

  Hereinafter, the details of the mounting structure of each trigger machine 5a, 5b will be described with reference to FIG. 3 and FIG. 3A and 3B are views showing the relationship between the shape of the tire house and the location of the first trigger machine 5a, in which FIG. 3A is a side view and FIG. 3B is a top layout view. FIG. 4 is a perspective view of an installation location of the first trigger machine 5a. FIG. 5 is a layout diagram when the installation location of the first trigger machine 5a is viewed from the front (left) and the side (right) of the vehicle.

  As shown in FIGS. 3A and 3B, the wall surface 10a of the tire house 10 has a shape corresponding to the left front wheel 6b (wheel). The surface corresponding to the side surface of the running surface of the tire when the tire faces straight forward in the tire house 10 is substantially parallel to both the vehicle width direction and the vehicle height direction, and is shown in FIGS. As described above, the storage window portion 10b having a part of the surface opened in the surface is formed. A housing 11 made of a magnetic material such as a metal constituting a rectangular internal space is provided in the storage window 10b. The housing 11 is provided with a first via a stay or the like. A trigger machine 5a is attached.

  The casing 11 is arranged so that each side of the rectangular parallelepiped constituting the internal space is parallel to the vehicle width direction, the vehicle height direction, and the vehicle front-rear direction. For example, as shown in FIG. 4, the internal space dimension of the housing 11 is 10 cm in the vehicle width direction La, 10 cm in the vehicle height direction Lb, and 2 in the vehicle longitudinal direction (vehicle length direction) Lc. The first trigger device 5a is arranged at a substantially central position of the casing 11. As described above, the first trigger machine 5a has a core size of 10 mm × 10 mm × 50 mm, and is attached so that the central axes of the core 8 and the coil 9 are parallel to the vehicle width direction. The dimension L1 from the center of the core 8 to the inner wall surface of the casing 11 in the vehicle width direction is 50 mm (25 mm from the tip of the core 8), and the dimension L2 from the core 8 to the inner wall surface of the casing 11 in the vehicle height direction is It is 45 mm. The dimension L3 from one surface of the core 8 in the vehicle front-rear direction to the inner wall surface of the housing 11 (the bottom surface of the housing 11, that is, a surface parallel to both the vehicle width direction and the vehicle height direction) is, for example, 5 mm or more. ing.

Further, at least a part of the opening of the housing 11, that is, the storage window 10b, specifically, the region including the lower corner on the outside of the vehicle is magnetically covered with the lid 12 made of a magnetic material. It is supposed to be in a state. In the present embodiment, the lid body 12 is constituted by a right-angled isosceles triangle, and the dimensions of each side are 10 cm × 10 cm × 10 · 2 ^1/2 cm.

  Thus, the 1st trigger machine 5a is attached in the tire house 10 in the vehicle body 7. FIG. In addition, although the mounting structure of the 1st trigger machine 5a was demonstrated here, the mounting structure similar to the 1st trigger machine 5a is employ | adopted also about the 2nd trigger machine 5b. However, in the case of the present embodiment, since the second trigger machine 5b is disposed in front of the left rear wheel 6d, the storage window portion 10b is formed at the vehicle front position in the tire house 10, and the storage window portion 10b. Inside, the housing 11 is arranged such that the bottom surface of the housing 11 is positioned in front of the vehicle.

  Moreover, since it is set as such a structure, it becomes possible to acquire the effect demonstrated below.

  First, the effect based on the dimensional relationship between the first trigger machine 5a and each inner wall surface of the housing 11 will be described. In the present embodiment, as described above, the dimensions L1 to L3 from the core 8 of the first trigger machine 5a to the inner wall surfaces of the casing 11 are the above dimensions, and the interior of the casing 11 so as to satisfy the dimensions. The spatial dimensions La to Lc are the above dimensions. This is because, when the first trigger device 5a is arranged in the housing 11, the strength of the trigger signal output from the first trigger device 5a varies due to the influence of the magnetic member constituting the housing 11, and a desired strength is obtained. It is because it becomes impossible.

  6 (a) and 6 (b) respectively show a predetermined distance from the first trigger machine 5a when the dimensions L1 and L2 are changed, with the vehicle width direction dimension of the core 8 being Lw and the vehicle height direction dimension being Lh. It is the graph which measured the magnetic field intensity in the position away (for example, 60 cm) by experiment.

  As shown in FIG. 6 (a), when the dimension L1 is reduced, it is affected by the inner wall surface of the housing 11, so that the magnetic field strength is smaller than when a trigger signal is output from the first trigger device 5a in free space. Get smaller. This effect becomes smaller as the dimension L1 becomes larger, and when the dimension L1 = 1.1 Lw or more, a desired magnetic field strength (within -1 dB with respect to the magnetic field strength when the trigger signal is output in free space) can be obtained. It becomes.

  On the other hand, as shown in FIG. 6 (b), even when the dimension L2 is small, it is affected by the inner wall surface of the housing 11, and therefore compared with the case where the trigger signal is output from the first trigger device 5a in free space. The magnetic field strength is reduced. This effect becomes smaller as the dimension L2 becomes larger. When the dimension L2 is 1.5 Lh or more, a desired magnetic field strength (within -1 dB with respect to the magnetic field strength when the trigger signal is output in free space) can be obtained. It becomes.

  In addition, although the experimental result about the dimension L3 is not shown here, it can be said that the dimension L3 is the same as the dimension L2, and the dimension L3 = 1.5 Ld when the dimension in the vehicle longitudinal direction of the core 8 is Ld. If it becomes above, it will become possible to obtain desired magnetic field intensity. That is, in the radial direction about the axis of the core 8, the dimension from the side surface of the core 8 to the inner wall surface of the housing 11 on the line connected with the shortest distance to the inner wall surface of the housing 11 passing through the central axis of the core 8. (The dimensions L2 and L3 of this embodiment are applicable) as long as it is 1.5 times (1.5Lh, 1.5Ld) or more of the dimensions of the core 8 (the dimensions Lh and Ld of this embodiment are applicable). .

  As described above, when the first and second trigger machines 5a and 5b are accommodated in the housing 11, the dimensions of the trigger signal so that the magnetic field strength of the trigger signal does not decrease due to the influence of the magnetic material constituting the housing 11. L1 is 1.1 Lw or more, dimension L2 is 1.5 Lh or more, and dimension L3 is 1.5 Ld or more. As a result, a decrease in the magnetic field strength of the trigger signal can be suppressed, and the trigger signal can be received by the transceiver 2 that wants to reliably receive the trigger signal.

  Next, the effect of covering a part of the opening of the housing 11 with the lid body 12 made of a magnetic material will be described. As described above, the region including the lower corner on the outside of the vehicle in the opening of the housing 11 is magnetically covered with the lid 12 made of a magnetic material. For this reason, the trigger signal output from the 1st trigger machine 5a is influenced by the wall surface of the cover body 12, and it becomes possible to change the directivity of a trigger signal. This will be described with reference to FIG. 7 and FIG.

  7 and 8 respectively show a state in which the opening of the housing 11 is not covered with the cover 12 as shown in the center of the figure, and the lower side of the opening of the housing 11 outside the vehicle. It is the figure which showed the result of having analyzed the magnetic intensity distribution which shows the directivity of a trigger signal about the state which covered the half area | region with the cover body. 7 and 8, the left-right direction on the paper surface coincides with the vehicle width direction (the axial direction of the core 8), and the up-down direction on the paper surface coincides with the vehicle height direction.

  As shown in FIG. 7, when the opening of the housing 11 is not covered with the lid body 12, the magnetic intensity distribution is centered on a straight line parallel to the vehicle height direction passing through the axis of the core 8 and the center of the core 8. Becomes line symmetric. In the case of such a magnetic intensity distribution, when a line parallel to the vehicle width direction and a line parallel to the vehicle height direction passing through the center of the trigger machine 5 are drawn, the trigger machine 5 is centered on these lines. The position where the angle is inclined becomes the place where the magnetic strength is weakened. For this reason, when the magnetic strength is weakened at a lower position near the pole of the vehicle 1 and an adjacent vehicle is positioned near the pole of the vehicle 1, the trigger signal output by the trigger machine 5 provided in the vehicle 1 is adjacent. Although it can be prevented from being received by the transmitter / receiver of the vehicle, the trigger signal may be received by the transmitter / receiver with respect to an adjacent vehicle slightly apart.

  On the other hand, as shown in FIG. 8, if the lower half region outside the vehicle in the opening of the housing 11 is covered with the lid 12, the shaft of the core 8 and the core 8 The magnetic intensity distribution is not line-symmetric about a straight line parallel to the vehicle height direction passing through the center. Specifically, when a line parallel to the vehicle width direction and a line parallel to the vehicle height direction passing through the center of the trigger machine 5 are drawn, the magnetic field outside the vehicle is centered on the trigger machine 5 with respect to each line. The magnetic field strength distribution rotates as a whole so that the strength distribution is directed upward as compared with the case of FIG. That is, the directivity of the trigger signal changes due to the influence of the wall surface of the lid 12 by the amount covered with the lid 12 compared to the case of FIG. For this reason, compared with the case shown in FIG. 7, the place where magnetic intensity weakens also moves upwards. Accordingly, the magnetic strength at the lower position is weakened over a certain distance from the pole vicinity of the vehicle 1, and not only when the adjacent vehicle is located in the pole vicinity of the vehicle 1 but also with respect to an adjacent vehicle that is slightly apart. The signal can be prevented from being received by the transceiver.

  Thus, by covering a part of the opening of the housing 11 with the lid 12 made of a magnetic material, the directivity of the trigger signal can be controlled. Then, the lid 12 covers the region including the lower corner on the outside of the vehicle in the opening of the housing 11, thereby moving the position where the magnetic strength on the outside of the vehicle is weak to the upper side. Thereby, it can suppress that a trigger signal is received with the transmitter / receiver of an adjacent vehicle, and it becomes possible to suppress malfunctioning of the transmitter / receiver by the trigger signal of another vehicle.

  Thus, in order to control the directivity of the trigger signal output from the trigger machine 5 by the lid body 12, the distance from the lid body 12 to the trigger machine 5 needs to be 50 mm or less. For this reason, the arrangement relationship between the lid 12 and the trigger device 5 is set so that the relationship of dimension L4 = 1.5 Ld from the side surface of the core 8 to the wall surface of the lid 12 located inside the housing 11 is established. ing.

  In the present embodiment, since a part of the opening of the housing 11 is covered with the lid 12, the magnetic field strength of the trigger signal is reduced as compared with a case where the opening is not covered with the lid 12. However, even if half of the opening of the housing 11 is covered with the lid 12, sufficient magnetic field strength can be obtained. FIG. 9 is a diagram showing the results of measuring the maximum magnetic field strength when the ratio S ′ / S of the area S ′ of the portion not covered by the lid 12 to the area S of the opening of the housing 11 is changed. is there. As shown in this figure, when the ratio S ′ / S is 25% or more, the ratio S ′ / S is 100%, that is, when the opening of the housing 11 is not covered at all by the lid 12. The reduction in the maximum magnetic field strength is 6 dB or less. For this reason, the ratio S ′ / S should be 25% or more, and sufficient magnetic field strength can be obtained if the ratio S ′ / S is 50% or more as in this embodiment.

  Although the second trigger machine 5b has been described as an example here, the same can be said for the first trigger machine 5a as well as the second trigger machine 5b.

  As described above, in the present embodiment, in the tire air pressure detection device that performs wheel position detection and tire air pressure detection processing based on the trigger signal output from the trigger machine 5, the storage window 10b is provided in the tire house 10, The housing 11 is disposed in the storage window 10b, and the trigger machine 5 is attached in the housing 11. For this reason, it is not necessary to make the inside of the tire house 10 into the dimension which considered the mounting space of the trigger machine 5. FIG. Therefore, the structure inside the tire house 10 can be a mounting structure of the trigger machine 5 that does not require considering the mounting space of the trigger machine 5. And since each dimension L1-L3 from the trigger machine 5 to the inner wall surface of the housing | casing 11 becomes the said dimension, it prevents that the magnetic strength of a trigger signal falls by the influence of the inner wall surface of the housing | casing 11. it can.

  Moreover, in this embodiment, the directivity of the trigger signal of the trigger machine 5 is controlled by having a structure in which a part of the housing 11 is covered with a lid body 12 made of a magnetic material. For this reason, it is possible to obtain desired directivity without bending the core 8. Therefore, the height in the radial direction with respect to the axis of the core 8 can be reduced compared to the case where the core 8 is bent, and the size of the trigger machine 5 does not have to be increased. Thereby, the structure in the tire house 10 does not need to consider the mounting space of the trigger machine 5, and the mounting structure of the trigger machine 5 can obtain desired directivity without bending the core 8. It becomes possible to do.

(Other embodiments)
In the above embodiment, the case where the lid 12 covering the opening of the housing 11 is entirely made of a magnetic material has been described. However, it is only necessary that the opening of the housing 11 can be magnetically covered. Of the opening, only the portion that is desired to be magnetically covered may be made of a magnetic material, and the other portion may be made of a non-magnetic material plate such as a resin plate. In the case of such a structure, it is possible to physically cover all the openings of the housing 11 with the lid body 12, and thus it is possible to prevent foreign matter from entering the housing 11.

  Moreover, in the said embodiment, although an example of the position of the cover body 12 which covers the opening part of the cover body 11 was shown, a place can also be changed suitably according to the directivity requested | required.

  Moreover, although the said embodiment demonstrated the case where the 1st, 2nd trigger machine 5a, 5b was arrange | positioned in the vicinity of the left front-rear wheel 6b, 6d, these are arrange | positioned in the vicinity of the right front-rear wheel 6a, 6c. Alternatively, the trigger machine 5 may be arranged near the right wheel for one of the front wheels and the rear wheel, and the trigger machine 5 may be arranged near the left wheel for the other.

  Moreover, in the said embodiment, although the 1st trigger machine 5a was arrange | positioned in the back of the left front wheel 6b, and the 2nd trigger machine 5b was arrange | positioned in front of the left rear wheel 6d, these arrangement | positioning was only an example. Instead, the first trigger device 5a may be disposed in front of the left front wheel 6b, or the second trigger device 5b may be disposed behind the left rear wheel 6d.

1 is a block diagram illustrating an overall configuration of a tire air pressure detection device to which a first embodiment of the present invention is applied. It is the typical enlarged view which showed the structure of the trigger machine. It is the figure which showed the relationship between the shape of a tire house, and the arrangement place of the 1st trigger machine 5a, (a) is a side view, (b) is an upper surface layout figure. It is a perspective view of the attachment place of the 1st trigger machine 5a. It is a layout figure when the attachment place of the 1st trigger machine 5a is seen from the vehicle front and side. (A), (b) is the graph which showed the magnetic field intensity when changing dimension L1, L2 by making the vehicle width direction dimension of the core 8 into Lw, and a vehicle height direction dimension to Lh. It is the figure which showed the result of having analyzed the magnetic intensity distribution which shows the directivity of a trigger signal about the state which does not cover the opening part of the housing | casing 11 with the cover body at all. It is the figure which showed the result of having analyzed the magnetic intensity distribution which shows the directivity of a trigger signal about the state which covered the lower half area | region in the opening part of the housing | casing 11 with the cover body 12 outside. FIG. 6 is a diagram showing the result of measuring the maximum magnetic field strength when the ratio S ′ / S of the area S ′ of the portion not covered by the lid body 12 with respect to the area S of the opening of the housing 11 is changed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Transceiver 3 Receiver 4 Indicator 5 Trigger machine 6a-6d Wheel 7 Car body 8 Core 9 Coil 10 Tire house 10a Wall surface 10b Storage window part 11 Case 12 Lid

Claims (4)

A trigger signal is output from the trigger machine (5) toward the transceiver (2) provided to each of the plurality of wheels (6a to 6d), the trigger signal is received by the transceiver (2), The tire pressure for a vehicle that detects the wheel position or the tire pressure by outputting the data of the reception intensity of the trigger signal and the data about the tire pressure of the plurality of wheels (6a to 6d) from the transceiver (2). A trigger machine mounting structure in the detection device,
The trigger machine (5) is a magnetic field antenna that generates a magnetic field that constitutes the trigger signal by winding a core (8) with a coil (9) and causing a current to flow through the coil (9). And is installed in a tire house (10) where the plurality of wheels (6a to 6d) are arranged,
The tire house (10) is formed with a storage window (10b) in which a part of the wall surface (10a) of the tire house (10) is opened, and inside the storage window (10b). A housing (11) made of a magnetic material that constitutes a space and has an opening on one side is provided,
In the internal space formed by the casing (11), the axial direction of the core (8) is parallel to the vehicle width direction, and the casing in the axial direction of the core (8) from the center of the core (8). The dimension (L1) to the inner wall surface of the body (11) is 1.1 times (1.1Lw) or more of the axial dimension (Lw) of the core (8), and the axis of the core (8) In a radial direction centered on the core (8) from the side surface of the core (8) to the inner wall surface of the housing (11) passing through the central axis of the core (8) from the side surface of the core (8). The trigger machine (5) so that the dimension (L2, L3) to the inner wall surface of the core is 1.5 times (1.5Lh, 1.5Ld) or more than the dimension (Lh, Ld) of the core (8). A trigger machine mounting structure in a tire air pressure detecting device, wherein:   When a part of the opening of the casing (11) is covered with a lid (12) made of a magnetic material, the trigger signal output from the trigger machine (5) is in free space. The trigger machine mounting structure in the tire air pressure detecting device according to claim 1, wherein the structure is shifted with respect to the directivity of the tire air pressure. The internal space of the housing (11) is a rectangular parallelepiped composed of sides that are parallel to the vehicle width direction, the vehicle height direction, and the vehicle front-rear direction,
The tire pressure detection according to claim 2, wherein the lid (12) is a triangle that covers a region including a lower corner of the opening (1) outside the vehicle (1). Trigger device mounting structure in the device.   A ratio (S ′ / S) of an area (S ′) of a region of the opening (11) not covered with the lid (12) to the area (S) of the opening is 25. The trigger machine mounting structure in the tire air pressure detecting device according to claim 2 or 3, wherein the structure is set to be equal to or more than%.

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